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                                     EPA-600/9-76-023
                                     October 1976
               PROCEEDINGS

FOURTH UNITED STATES/JAPAN CONFERENCE ON
       SEWAGE TREATMENT TECHNOLOGY
Cincinnati, Ohio:   October 23-24, 1975
Washington, D.C.:   October 28-29, 1975
   Office of International Activities
 Office of Water and Hazardous Materials
         Washington, B.C.  20460

   Office of Research and Development
         Washington, D.C.  20460
         Cincinnati, Ohio  45268
  U.S. ENVIRONMENTAL PROTECTION AGENCY
   OFFICE OF RESEARCH AND DEVELOPMENT
         CINCINNATI, OHIO  45268

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                DISCLAIMER
These Proceedings have been reviewed by
the U.S. Environmental Protection Agency
and approved for publication.  Approval
does not signify that the contents
necessarily reflect the views and policies
of the U.S. Environmental Protection
Agency, nor does mention of trade names
or commercial products constitute en-
dorsement or recommendation for use.
                     ii

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                        FOREWORD
    The  industry and technical ability of the Japanese and
American people have brought prosperity to our two nations
but have also created grave strains on the environment.
Both nations  are conscious of the need to control pollution
and protect the environment.

    US-Japan environmental cooperation has been going on
for several years.  The fruits of our mutual labors are
becoming visible.  The United States and Japan have now
completed the fourth in a series of  Joint  Conferences on
Sewage Treatment Technology. Both countries have profited
from this exchange. These Proceedings, representing  the
most up-to-date information  in several areas of wastewater
treatment, will be welcomed for their contribution to our
knowledge in this field/"
                             Russell E. Train
                              Administrator
Washington, B.C.
July, 1976

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                     CONTENTS
FOREWORD
JAPANESE DELEGATION                           vi
U. S. - CINCINNATI DELEGATION                 vii
U. S. - WASHINGTON DELEGATION                 viii
JOINT COMMUNIQUE
JAPANESE PAPERS
    1 THROUGH 8
EPA - CINCINNATI PAPERS                     503
EPA - WASHINGTON PAPERS                     628

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                 JAPANESE DELEGATION
DR. TAKESHI KUBO
  Head of Delegation, Executive Director,  Japan Sewage
  Works Agency

TOHRU HAYASHI
  Head, Water Quality Control Division, Water Quality
  Bureau, Environmental Agency

DR. MAMORU-KASHIWAYA
  Head, Water Quality Control Division, Public Works
  Research Institute, Ministry of Construction

KEN MURAKAMI
  Chief, Water Quality Section, Water Quality Control
  Division, Public Works Research Institute, Ministry of
  Construction

DR. AKINORI SUGIKI
  Head, Research and Technology Development Division,
  Japan Sewage Works Agency

MASAYUKI SATO
  Director, Sewage Works Bureau, Yokohama City Office

SEIICHI YASUDA
  Director, Sewage Works Bureau, Kyoto City Office

SATORU TOHYAMA
  Head of Sewage Works Division, Dept. of Sewerage
  & Sewage Purification, Ministry of Construction

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                            UNITED STATES/CINCINNATI DELEGATION
FRANCIS M. MIDDLETON
  General Chairman of the Conference and
  Head of the Cincinnati U.S. Delegation;
  (Acting) Senior Science Advisor, MERL

LOUIS W. LEFKE
  (Acting) Director, MERL

EDWIN F. EARTH
  Chief, Biological Treatment Section,
  TPDB, WRD, MERL

RICHARD C. BRENNER
  Sanitary Engineer, Biological Treatment
  Process Branch, WRD, MERL

JOHN CIANCIA
  Sub-Program Chief, Industrial Treatment
  and Control, Industrial Environmental
  Research Laboratory (Edison, New Jersey)

JESSE M. COHEN
  Chief, Physical-Chemical Treatment
  Section, TPDB, WRD, MERL

JOHN J. CONVERY
  (Acting) Director, WRD, MERL

JOHN N. ENGLISH
  Sanitary Engineer, Municipal Treatment
  and Reuse Section, SEEB, WRD, MERL
DR. JOSEPH B. FARRELL
  Chief, Ultimate Disposal Section, TPDB,
  WRD, MERL

RICHARD I. FIELD
  Chief, Storm and Combined Sewer Section,
  SEEB, WRD, MERL (Edison, New Jersey)

ROBERT A. OLEXSEY
  MechanicaJ Engineer, Ultimate Disposal
  Section, TPDB, WRD, MERL

JOSEPH F. ROESLER
  Sanitary Engineer, Pilot and Field Eval-
  uation Section, Technology Development
  and Support Branch, WRD, MERL

B. VINCENT SALOTTO
  Research Chemist,  Ultimate Disposal
  Section, TPDB, WRD, MERL

DR. JAMES E. SMITH
  Sanitary Engineer, Ultimate Disposal
  Section, TPDB, WRD, MERL

JAMES  J.  WESTRICK
   Sanitary  Engineer,  Physical-Chemical
   Treatment  Section,  TPDB, WRD, MERL
MERL - Municipal Environmental Research Laboratory
WRD  - Wastewater Research Division
TPDB - Treatment Process Development Branch
SEEB - Systems and Engineering Evaluation  Branch
                                            Vll

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                           UNITED  STATES/WASHINGTON DELEGATION
FRANCIS M. MIDDLETON
  General Chairman  of  the  Conference;
  (Acting) Senior Science  Advisor,  MERL
  (Cincinnati,  Ohio)

JOHN T. RHETT
  Head of Washington U.S.  Delegation;
  Deputy Assistant  Administrator  for Water
  Program Operations,  OWHM

CHARLES H. SUTFIN
  Deputy Head  of Washington U.S.  Delegation;
  Deputy Director,  Municipal Construction
  Division,  Water Program  Operations,  OWHM

ROBERT A. CANHAM
  Executive  Secretary, Water Pollution
  Control Federation

FRANCIS J. CONDON
  Sanitary Engineer, Community Sources
  Staff, Waste Management  Division, Air,
  Land, and  Water Use, ORD

FITZHUGH GREEN
  Associate  Administrator  for International
  Activities

ERNEST P. HALL
  Deputy Director,  Effluent Guidelines
  Division,  Water Planning and Standards,
  OWHM
JOE G. MOORE, JR.
  Program Director, "National Commission
  on Water Quality

WALTER S. GROSZYK
  Deputy Director, Water Planning Division,
  Water Planning and Standards, OWHM

WILLIAM A. ROSENKRANZ
  (Acting) Director, Waste Management
  Division, Air, Land, and Water Use, ORD

ROBERT B. SCHAFFER
  Director, Permits Division, Water
  Enforcement, Office of Enforcement

DR. WILSON K. TALLEY
  Assistant Administrator for Research
  and Development

CALVIN C. TAYLOR
  Economic Analyst,  Interagency Liaison
  Office, Region IV (Atlanta, Georgia)
ADDITIONAL PARTICIPANT
KIRK MACONAUGHEY
  Japanese Coordinator,  Office of
  International Activities
OWHM - Office of Water and Hazardous Materials
ORD  - Office of Research and Development
MERL - Municipal Environmental Research Laboratory
                                           VI11

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       DR. TAKESHI KUBO,  JAPANESE  TEAM LEADER
   OPENS THE CONFERENCE AT  EPA IN  CINCINNATI, OHIO
                                      »mo sum ot
                                       NTAL MOUCTiQN  AGE
                                       OHMJKTM IIJUICU C«Tl*
:
         JAPANESE TEAM VISITS  THE NEW EPA
 ENVIRONMENTAL RESEARCH  CENTER,  CINCINNATI, OHIO
                         ix

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   JAPANESE VISIT ROCKY RIVER,  OHIO
   PHYSICAL-CHEMICAL TREATMENT  PLANT
  JAPANESE VISIT CONSTRUCTION SITE
OF PHYSICAL-CHEMICAL TREATMENT PLANT
      NIAGARA FALLS, NEW YORK

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X
H-
                            JOE G, MOORE (FAR LEFT) ADDRESSES JOINT CONFERENCE - WASHINGTON, D,C,

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                                 Joint Communique

           Fourth U.S./Japan Conference on Sewage Treatment Technology

                                Washington, D. C.

                                 October 29, 1975


     1.  The Fourth United States/Japan Conference on Sewage Treatment Technology
was held in Cincinnati, Ohio and Washington, D. C., from October 23-29, 1975.

     2.  The Japanese delegation, headed by Dr. Takeshi Kubo, Executive Director,
Japan Sewage Works Agency, was composed of six National Government officials and
two local Government officials.

     3.  Mr. Frank M. Middleton, Senior Science Advisor, U. S. Environmental
Protection Agency, Cincinnati, Ohio, was General Chairman of the Conference.
Mr. John T. Rhett, Deputy Assistant Administrator for Water Program Operations
was Head of the Washington delegation.  Mr. Charles H. Sutfin, Deputy Director,
Municipal Construction Division, was Deputy Head of the Washington delegation.
In addition to EPA officials, Conference delegates included Joe G. Moore, Jr.,
Program Director, National Commission on Water Quality, and Robert A. Canham,
Executive Secretary, Water Pollution Control Federation.

     4.  Prior to the Conference the Japanese delegates visited advanced waste
treatment facilities in Orange County, California, and Escondido, California.
Physical chemical treatment plants were seen in Rocky River, Ohio, Cleveland,
Ohio, and Niagara Falls, New York.  The pure oxygen treatment plant in Detroit,
Michigan was visited.  In Washington, D. C., the EPA Blue Plains Sewage Treatment
Pilot Plant was visited and a tour of the Piscataway tertiary treatment plant
was made.

     5.  Principal topics of the Fourth Conference in Cincinnati were status of
pure oxygen use, sludge handling and disposal by heat treatment, incineration and
land disposal, urban storm water technology, automation and instrumentation, use
of activated carbon, filtration, phosphorus removal, industrial waste treatment
progress, reuse and disinfection.  In Washington the U. S. side discussed aspects
of Public Law 92-500 including planning, urban runoff, permits, pretreatment, con-
struction grants status and the tentative conclusions of the National Commission
on Water Quality.  The Japanese side discussed environmental improvement in
Japan, comprehensive planning, combined sewer overflow technology, pretreatment
and case histories of industrial waste treatment.  Vigorous discussions followed
the conference presentations.

     6.  Recent personnel exchanges include a month-long visit to Japan by Dr.
James E. Smith and Mr. Dolloff F. Bishop of the EPA Taft Center, Cincinnati, Ohio.
Dr. K. Inaba, Japan Sewage Works Agency, is spending six months in the United
States to study storm sewer flows and urban runoff problems.

     7.  In the research area it was agreed to enter into joint projects in areas
of municipal sludge disposal technology, agricultural use of sludge, nitrogen
control technology, instrumentation and automation of wastewater treatment plants
and other interests to both countries.  Researchers on both sides will exchange
information on a regular basis.  Full reports will be given at future conferences.

      8.   It was proposed by the Japanese side that the Fifth U. S./Japan Conference
 should be held in Japan, about May 1977-

      9.   A Proceedings of the Conference will be printed in English and Japanese.

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                           Fourth US/JAPAN Conference
                                    on
                           Sewage Treatment Technology
                                 Paper No. 1
SLUDGE TREATMENT  AND  DISPOSAL
               October 24, 1975
               Cincinnati, Ohio
           Ministry of Construction
             Japanese Government

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                  SLUDGE  TREATMENT AND DISPOSAL


1.  Sludge Handling Practice in Japan	     	    4
     A. Sugiki, Japan Sewage Works Agency

2.  Studies on Performance for Sewage Sludge Dewatering Process   	   10
     A. Sugiki, Japan Sewage Works Agency

3. Sewage Sludge Treatment and Disposal as Practiced in Yokohama City —
   "Reclamation to Agricultural Land and Green Field" Program —	25
     M. Sato, Yokohama City

4. The Treatment and Disposal  of Sludge at Toba Treatment Plant	33
     5. Yasuda, Kyoto City

5. Sludge Production and Solid Loading Balance in the Nishiyama STP,
   Nagoya     .                    	        	46
      T. Annaka and M. Kashiwaya, PWRI, Ministry of Construction

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         CHAPTER  1.  SLUDGE HANDLING PRACTICE  IN JAPAN

1.1  Introduction .            	     .
1.2  Dewatering and Incineration of Sewage Sludge ...
1.3  Research and Technological Development     	     .
                                     4 -

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1.1  INTRODUCTION

     Ihe number of publicly owned sewage treatment plants in operation in Japan
amounts to  169 as of 1973. The sludge by weight produced out of those plants is
extremely massive. The volume by weight per capita of sludge produced is estimated
in Japan on the basis of Suspended Solid, SS, content in the incoming sewage.
     Since the grams per capita of SS in sewage is, at present, found to stand at 40
grams and BOD5 at 44 grams, the  sludge volume by weight produced comes up to
36 grams on condition that the removal rate of SS is 80 percent by secondary treat-
ment process.  On  the other hand, according  to  a  survey conducted by  the Japan
Sewage Works Agency, 20 liters of sludge with the solid contents having 2 percent on
an average are being produced per capita a day, indicating a value almost close to the
calculated above. It is  known, however, that at  some treatment plants  where the
activated sludge process is  adopted the sludge volume produced  exceeds the value
mentioned above approximately by 10 percent.
     As for  the sludge generated in the treatment  process, it is necessary to study
the sludge in preliminary sedimention basin, the excess sludge originating  from  acti-
vated sludge, the suspended solids existing in recycle flow that grows out of a sludge
treatment system and the material balance of sludge in a treatment system.  Recently,
the necessity of surveys of this kind has been keenly recognized  and results of  such
attempts are partly described in this report from the City of Kyoto and a report on
the Nishiyama Treatment Plant, Nagoya City  studied by the Public Works Research
Institute, Ministry of Construction, both to be referred to in this paper.
     According to  the studies carried out by the  Ministry of Construction in 1967,
systems of sludge  treatment and disposal can be summarized as  follows.  The most
prevailing system in use at 169 treatment plants which had been  then in  operation
was  that of "thickening—unaerobic digestion—mechanical dewatering", accounting
for 35  percents while 25 percents was for that of "unaerobic digestion—drying bed"
The treatment plants where sludge was incinerated were only those 10 established in
big cities.
     As for disposal systems, the land-filling was adopted at 97 treatment plants and
the  sludge  from 30 treatment plants are applied on agricultural land as fertilizer
and/or soil conditioner, thus sludge having been returned to the earth at 80 percents
of the total treatment plants.
     A  study made in  1973 shows that  the treatment  plants where the  system of
"unaerobic digestion—mechanical dewatering" was adopted numbered 77, accounting
for 29 percents of all, while at 55 treatment plants (21 percents) raw sludge was  dire-
ctly  dewatered  by  a machine. The  number of plants where drying bed was installed
was 24, indicating a decrease at the time of 1967.
     In  the case of small-scale treatment plants, an increase was noticed in the adop-
tion of aerobic digestion.  34 treatment plants were equipped with incinerator, ac-
counting for 13  percent of the total, and at 17 of them the system of "raw sludge
dewatering-incineration" was adopted while that of "digestion-dewatering-incine-
ration" was at the remaining 17.
     Types of filtering  / dewatering machine shown in the results of 1973 study are
classified as follows:
                                   -  5 -

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     -vacuum filter;  135 treatment plants  381 sets
     -filter press;      14 treatment plants   39 sets
     -centrifuge;      20 treatment plants   36 sets
         Total       169 treatment plants
     Also types of incinerating / drying apparatus are as follows:
     —vertical multiple-hearth incinerator;   32 treatment plants  39 units
     —rotary  kiln;                          6 treatment plants   6 units
     —fluidized bed incinerator;             2 treatment plants   2 units
     The reason why the system of "unaerobic digestion—mechanical dewatering
(drying bed)—land-filling" heretofore in use has gradually been switched over to that
of "raw sludge dewatering-incineration—land-filling" is because sludge became nec-
essary to be treated efficiently with the increase in sludge volume produced, as well
as because  the necessity arose to reduce as much as possible the volume of sludge to
be disposed,  as it became difficult to find available land for  sludge disposal.  Some
other reasons why the latter system became more in use are considered to be because
     —land required for digestion and drying bed turned out to be extremely diffi-
      cult;
     —the  former system requires longer sludge  detention time and more labor for
      sludge treatment;
     —the operation of the former is rather complicated and necessitates skill  labor.
     However, as the methane gas produced from unaerobic digestion has been put
to use  or sludge has been utilized for  an  agricultural soil conditioner since the oil
crisis from  the viewpoint of resources and energy saving, the need to reevaluate un-
aerobic digestion from the sanitary engineering aspect  started to be recognized in-
creasingly.

1.2  DEWATERING AND INCINERATION OF  SEWAGE SLUDGE

     As mentioned above, in respect to types of sludge dewatering machine a great
number of treatment plants were found to have adopted vacuum filters. 4 out of
16 filter  presses were in use for dewater sludge after the heat treatment. Ferric cho-
loride (Fe  Cb) and lime (Ca(OH)2) were applied for  conditioning  to  dewatering.
Moisture content was 70 to 75 percents in vacuum filter and 55  to  60 percents in
filter press. On the other hand, sludge treated the heat  treatment was able to  be de-
watered down to the moisture content  of 35  to 40%. According to a research made
by the Agency last year on the actual conditions of dewatering devices in  use at
medium- and small-scale treatment plants, the volume of chemicals dosed fairly ex-
ceeded the designed value. This seems mainly to have  aimed at surer operation of
dewater,  but its cause is now under investigation  in detail.
     Centrifuges were once  employed  for the physicochemical treatment of  night-
soil and also employed for sewage sludge dewatering at some of the sewage treatment
plants.  But this type had not been adopted so widely due to the poor solids recovery
and  the problems of vibration and noise. Nevertheless, this type of machine is suita-
ble for medium- and small-scale treatment plants on account of such merits that
     -  it can be compact in size after being kept in a small container for noise and
       odor control.
                                    - 6  -

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     - it can run automatically in continiously and its maintenance is easy;
     - it requires auxiliary facilities less.
     This may also be reasoned out from the fact that in those cities where this type
is adopted many of the treatment  plants are given the  sludge treatment capacity of
more than 4  cubic meters but less than 100 cubic meters. In this type, the moisture
content can be reduced to 80% to 85% by adding polyelectrolytes (or polymer) in
the centrifugal dewatering, and since usual lime and  ferric chloride are not applied,
the volume of ash necessarily lessens when incinerating sludge. These merits of cen-
trifuge in  the operation  and maintenance coupled with a merit in the incineration
have accordingly led big cities to consider the possible adoption of this type.
     A new series of this type of machine has begun to  be introduced, with its num-
ber of revolutions reduced to  1,200 to 1,900 revolutions per minute and vibration,
noise and durability are improved.
     As for incinerators,  the reason why many of  them  are  of vertical multiple-
hearth type is because its function has been strengthened  so  much, after years of
technological improvement,  as to be able to treat sewage sludge almost without any
difficulty. Assuming that  the moisture  content of sludge is  70%, the capacity of in-
cinerator is found to be 5 to 250 tons per day in the case of multiple-hearth type,
4 to 60 tons  per day in rotary kiln and 5  to 20  tons per day in fluidized bed type.
Rotary  kiln consumes much fuel  and  seems to  be considered inadequate  for  the
adoption from the  standpoint of energy conservation.  Fluidized bed incinerator is
suitable for medium- and  small-scale plants, since the structure is simplified and the
intermittent operation is  economically feasible due to  its high heat capacity. Such
defects, however, are pointed out that  the volume produced of NOx and  powdered
dust is considerable, and the power cost of blower is high as it requires high-pressure
air.  Yet, in order to overcome these defects such improvements have been made as
to increase thermal efficiency by providing a spiral flow inside the funance and so
on. As a result, more this type of incinerator are coming to adopt it.
     Stack effluent  treatment is a matter to be taken into account inevitably when
incineration is brought into  focus. As the restrictions on air pollution have gradually
strengther, the treatment  of waste  gas from sludge incinerators accordingly came to
require more complicated-one. Soot and dust, gases of SOx, HC1, Ch and others in
exhaust gas are  considered harmful, and to cope  with them scrubbers or washing
with alkali and so forth have been employed. Recently, however, a wet-type electric
precipitator and / or a after burning apparatus have been obliged to be added further
in some areas. In the regions where a strict standard is enforced, the cost of equip-
ment for waste gas treatment has gone so  high as to exceed 50 percents of the cost
of total incineration facilities. As a result, under study are new methods,  for exam-
ple,  of heat treatment by which  sludge is dewatered without dosing much of the
chemicals  but treatment of cooking liquors, would be required to develop in future.
     On account of the fact that considerable energy is consumed in the incineration
of sludge,  the introduction of methods based on a new  idea of incinerating-with the
least possible energy is now  under  study. For instance, the  first machine  of the so-
called CG Process in which sludge is evaporated after being mixed with oil  is selected
for sewage treatment plant  of Fukuchiyama City, and a Lucas-type incinerator in

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Maebashi  City, both  being  under construction  at present. The Agency has been
studying the performances of sludge dewatering since last fiscal year, of which result
will be partly reported to this conference, and starting this fiscal year another study
on the performances of incinerators and waste gas treatment facilities was decided to
be carried out. This program is  aimed to produce basic data for the preparing of ra-
tional design criteria, on the standpoint of systematic approach.
     As for new-type facilities for sludge treatment set up in  the cities of Fukuchi-
yama and Maebashi, it is planned by the Agency to analyse their process perform-
ance and to evaluate them, upon coming into actual operation.

1.3  RESEARCH AND TECHNOLOGICAL DEVELOPMENT

     With the increase in the volume of sludge to be disposed, the Ministry of Con-
struction, Japanese government, decided to augment to a great extent the budget for
study and research on sludge treatment and disposal starting this fiscal year.
     Sludee has been utilized for  an agricultural  fertilizer or a soil conditioner since
long time ago.  The Japan Society of Civil Engineers has been studying sewage
sludge application on agricultural land  since 1969.
     The volume of sludge to be  applied depends upon what plant to be cultured,
but in the case of paddy rice the  upper limit of application was considered to be 100
kilograms per  ha.,  and the desirable rate of an  application to vegetables and fruit
trees, etc. was  found to be more or less 250 kilograms per ha.   It is of necessity,
however,  to make clear how soils and plants will be affected  by heavy metals con-
tained in  sludge. The Japan Society of Civil Engineers studied this subject for two
years, and starting this fiscal year the Agency is supposed to carry out an ecological
study on the effect over soils and plants when sludge is applied continuously.
     Yokohama City started a study on the use of sewage sludge on agricultural land
in 1971 and constructed a drying facility based on the study results. That facility is
now in practical use and further detail will be given in the chapter III.
     Various attempts to recover  the useful ingredients in sludge have been made so
far, and the one to utilize an available gas after drying sludge up by distillation began
to be studied also in our county.
     The  supernatant originating  from sludge digestion and heat treatment used to
be sent back to a main plant and treated there. As far as the heat treatment superna-
tant is concerned, it is known that in Sapporo City and so forth a considerable por-
tion can be removed through biological treatment. However, this kind of supernatnat
contains a sizable amount of phosphorus and nitrogen aside  from organic matters,
and when the  supernatant is sent  back to a main plant those  phosphorus and nitro-
gen are to. -be discharged fairly  much into the treated water. Places where the super-
natant seems necessary to be treated separately from the standpoints of waste water
treatment and eutrophication measures are increasing in number. The Agency has
started a study and research on this problem since the beginning  of this fiscal year.
     On the other hand, the Public Works Research Institute has begun to study how
to recover organic matters from the supernatant to utilize for  carbonic resources for
biological denitrification.

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     The development of treatment and disposal method of tertiary-treatment sludge
is one of the important subjects to be studied more thoroughly in future. The Public
Works  Research Institute has already started a basic research on  the  recovery of
tertiary-treatment sludge, etc., and also  the  Agency is conducting a study and re-
search  on the  dewatering of sludge from a pilot plant at the Lake of  Biwa, Shiga
Prefecture. This paper covers hereinafter the following contents.
II.   Studies on Performance for Sewage Sludge Dewatering Processes
III.  Sewage Sludge Treatment and Disposal in Yokohama—Agricultural  Land Appli-
     cation.
IV.  Sludge Treatment and Disposal in Toba Sewage Treatment Plant, in Kyoto
V.   Material Balance of Solids in Nishiyama Sewage Treatment Plant in Nagoya City
                                      9 -

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CHAPTER 2.   STUDIES ON PERFORMANCE FOR SEWAGE SLUDGE
              DEWATERING  PROCESSES
2.1  Purpose.          	     	11
2.2  Statistics	          	11
  2.2.1   Sewage Plant and Dewatering Equipment .    	11
  2.2.2   Thickening	11
  2.2.3   Sludge Cake and Filtrate	12
  2.2.4   Conditioning..          	12
  2.2.5   Performance     	12
                                  10 -

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 2.1  PURPOSE

     At present, throughout Japanese main lands, 426 sewage plants are under opera-
 tion.  Recently a  activated sludge process becomes a standard means to cope with
 urban waste water. The process produces a large amount of sludge which requires
 another treatment. Therefore, almost all of the sewage plants have sludge dewatering
 equipments.
     Although design parameters of the dewatering machines are provided in some
 manuals, performances  of the machines are  not certain. Once machines are set up,
 not only design personnels but also regulatory agencies lost interests in them. Opera-
 tional experience and performance data are accumulated only locally. As a result,
 design technology of the machines does not improve but still remains under-develop-
 ment. A procedure to select the proper type which is most suitable for the local con-
 ditions is "the rule of a thumb". If his machine works properly, he is in bonanza.
 It is a little more than an art to determine his type.
     Through the year of 1975, sewered population will  exceed twenty  percent.
 The rest 80 percent people are scheduled to be sewered within few years. Therefore
 Japan is an attractive market for sewage equipment manufacturers. Their advertise-
'ment is like a kaleidoscope. This adds another confusion to local personnels.
     Japan Sewage Works Agency is responsible to provide municipalities with engi-
 neering consultations. We launched a research  project aiming primarily to establish
 "a standard procedure to select sludge dewatering equipment and to make a specifi-
 cation of the dewatering machines required for  satisfying the local conditions"
     The first step  approaching to  this goal is to  overview the present dewatering
 practices. Our staffs visited 170 sewage plants and collected operational data to build
 a  statistics which will show a rough  sketch of the sewage sludge dewatering practices
 in Japan.

 2.2  STATISTICS

 2.2.1   SEWAGE PLANT AND DEWATERING EQUIPMENT
     The main process  for waste water treatment and design capacity of the  170
 plants surveyed are summarized in Table 2.1.  64% of the total  170 plants are de-
 signed on the basis of the standard  activated sludge process and 28% are of the step
 aeration process.  A majority of the small plants whose capacity is less than 5,000
 m3 /day has the standard activated sludge process. A half of the middle class plants
 where capacity ranges from 20,000 to 100,000 m3/day has the standard activated
 sludge and the rest half has the step aeration.
     The  continuous rotary vacuum filter is the most commonly used  device for
 dewatering sewage sludge. This device is used  widely in the small and large sewage
 plants. 80 percents of the  170 plants are  equiped with this (Table 2.2).

 2.2.2  THICKENING
     Solids concentration in mixture of primary and secondary sludge ranges widely.
 Annual average values of the  concentration are distributed from 0.5 percents to 3.0
 percents. It is inefficient to feed the dewatering equipment. They are  too thin and
 should be concentrated.
                                    - 11  -

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     51  plants have only thickeners and 43 plants have primary thickeners, digesters,
elutriation, tanks, and secondary thickeners. The digesters are found in 101 sewage
plants. As a general  rule the small sewage plants have only the thickener as a pre-
treatment equipment. The digesters are practiced in a half of the large sewage plants
(Table 2.3).
     A number of the centrifuge that follows the digestion tanks is large. The half
number of the rotary vacuum filters is fed with digested sludge. All the filter press
and the rest half vacuum filters are  fed with mixture of raw primary and secondary
sludge (Table 2.4).
     4 percent solid concentration is a standard value for design of sludge dewatering
equipment. However, the annual  average  of this value in  102 plants exceeds this
standard value (Table 2.5).
     No  significant difference in solid concentration between digested  and undi-
gested sludge appears.
     As compared with the other sludge, thermal treated sludge has conspicuous
discrepancy in the solid concentration.

2.2.3  SLUDGE CAKE AND FILTRATE
     When rated  by  moisture concentrations included in the dewatered cake, the
filter press comes the first place. This can yield easily the cake of which moisture
content is less than 50 percent. The running up is  the centrifuge or the vacuum fil-
ter, depending on local conditions (Table 2.6).
     Suspended solid concentration in filtrate produced by the vacuum filter is gen-
erally less than that by centrifuge. The concentrations is no greater than 1000 mg/1,
except some  extra ordinal cases. Seven cases that the SS concentration in the filtrate
exceeds 3000 mg/1 are observed.

2.2.4  CONDITIONING
    , Lime and ferric chloride are the most commonly used chemicals for the purpose
of sludge conditioning in advance of either the vacuum filter or the filter press; 101
out of the 135 vacuum  filters are fed with the sludge which is conditioned by using
the lime and ferric chloride and so does 6 out of the 13 filter press.
     On the basis^of a dry solid, 25 percent and 10 percent are average feeding rates
of the lime and the ferri; chloride respectively. When lime dosage increases, propor-
tionally the ferric chloride dosage increases (Table 2.7). Even for conditioning di-
gested sludge, the same amount of these chemicals as for conditioning the undigested
sludge is widely used.
     Polymer is the only chemicals that are used to condition sludge for  the centri-
fuge. There is no plant where inorganic coagulant is dosed for centrifuge purposes.

2.2.5 ' PERFORMANCE
     Comparisons of design capacities and actual performances in  108 vacuum  filter
plants are shown on Table 2.8. The  case that an amount of sludge actually handled
is greater than the originally designed capacity is observed in 28 vacuum filter plants
and 4 filter press plants.
     One of the difficult decisions in selecting the centrifuge is how to satisfy both
                                    -  12 -

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efficiency in SS recovery and efficiency in dewatering. Usually an increase in the SS
recovery results in an decrease in the dewatering efficiency. If the fed sludge concen-
tration is more than 20,000 mg/1, more than 80 percents SS recovery rate is  ex-
pected.
     61  dewatering plants are operated between 3 and 6 hours daily, 35 are so less
than 3 hours and 36 are between 6 and 12 hours. Only  11 plants are operated  for
24 hours every day.
     An  amount  of raw sludge  produced is closely  related to  an amount  of raw
sewage to be treated. A correlation coefficient between the amounts of raw sewage
and raw sludge is 0.61  (Fig. 3.1). Every one cubic meter of the raw sewage treated,
about 20 liters of the raw sludge are produced during the course of the primary and
the secondary treatment.
     The raw sewage rate to  be treated and the power consumed by either of the
three dewatering equipments are  in a linear correlation (Fig. 3.2). A magnitude of its
tangential value is different, depending on the equipments; 0.037 KWH/m3  for the
vacuum filter, 0.0123  KWH/m3 for the centrifuge, and 0.0546 KWH/m3 for the fil-
ter  press. A energy consumption per unit solid is greatest for the filter press, middle
for the vacuum filter, and least  for the centrifuge.
                                       13

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                Table 2-1   Relationship between Design Capacity and Process
^^^-\^^ Process
Design ^^~^^^^
capacity (m3 ) ^^~^\^^
0 ~ 5,000
5,000- 10,000
10,000- 20,000
20,000- 50,000
50,000- 100,000
100,000-200,000
200,000 - 500,000
500,000 -
Total

1

14
11
6
8
10
6
8
1
64

2

0
0
0
2
0
0
2
0
4

3

1
1
4
5
1
0
0
0
12

4

0
0
0
1
1
0
0
0
2

5

2
4
* 3
19
10
5
4
2
49

6

0
0
1
1
1
0
0
0
3

7

3
4
4
7
1
0
0
0
19

8

0
0
0
0
4
3
2
0
9

9

1
0
0
0
0
0
0
0
1

10

0
0
0
2
0
0
0
0
2

11

0
0
0
1
0
0
0
0
1

1?

0
0
0
1
0
1
0
0
2

n

0
0
0
1
0
0
0
0
1

14

0
1
0
0
0
0
0
0
1

Total

21
21
18
48
28
15
16
3
170
Note:   1 : Conventional activated sludge process
        2 : Modified aeration process
        3 : High rate aeration sedimentation process
        4 : 1 &3
        5 : Step aeration process
        6 : 1&5
        7 : Trickling filter process
 8 :Hain sedimentation
 9 : Single Stage  Digestion
10 : Neutralization
11 : 3&7
12 : 5&8
13 : 1&7
14 : Others
                                        - 14 -

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Table 2-2  Relationship between Design Capacity and Type of Dewatering Machine
\Type of dewatering
NS. machine
Design ^~~--\^^
capacity (m3) ~\^^
0- 5,000
5,000- 10,000
10,000- 20,000
20,000- 50,000
50,000- 100,000
100,000 - 200,000
200,000 - 500,000
500,000 -
Total


Vacuum filter

17
17
13
42
19
11
13
3
135


Centrifuge

3
3
5
3
6
0
1
0
21


Filter press

0
1
0
3
3
4
2
0
13


Others

1
0
0
0
0
0
0
0
1


Total

21
21
18
48
28
15
16
3
170
                                   15  -

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Table 2-3  Relationship between Treatment System and Capacity
^""""^^^^ Capacity (average)
Treatme^^S^y
system ^^~~~~-^^^
1-2-3-4
1-2-3
1-2-4
1-2
1-3-4
1-3
1-4
1
2-3-4
2-3
2-4
2
3-4
3
4
Others
Total

0
~ 5,000

6
1
0
5
0
0
3
15
2
1
0
1
0
0
0
7
41

5,000
~ 10,000

2
2
0
4
0
0
1
2
2
0
0
2
0
0
0
0
15

10,000
~ 20,000

6
3
0
1
0
0
0
8
1
1
0
2
0
0
0
1
23

20,000
~ 50,000

14
5
0
2
0
0
1
14
0
2
0
1
0
0
0
0
39

50,000
~ 100,000

7
3
1
1
0
0
1
10
1
3
0
1
0
0
0
2
30

100,000
~ 200,000

4
1
1
3
0
0
1
2
0
1
0
0
0
0
0
0
13

200,000
~ 500,000

2
2
0
2
0
0
1
0
0
0
0
0
0
0
0
0
7

500,000

2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2

Total

43
17
2
18
0
0
8
51
6
8
0
7
0
0
0
10
170
   Note:   1 : Thickner
           2 : Digestion tank
           3 : Sludge elutriation tank
           4 : Sludge storage tank

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Table 2-4  Relationship between Treatment System and Type of Dewatering Machine
\Type of dewatering
^•^_ machine
system ^"~~\^
1-2-3-4
1-2-3
1-2-4
1-2
1-3-4
1-3
1-4
1
2-34
2-3
2-4
2
3-4
3
4
Others
Total
Vacuum filter

39
16
2
13
0
0
6
38
6
1
0
3
0
0
0
5
135
Centrifuge

2
0
0
5
0
0
1
4
0
1
0
4
0
0
0
4
21
Filter press

2
1
0
0
0
0
1
8
0
0
0
0
0
0
0
1
13
Others

0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
1
Total

43
17
2
18
0
0
8
51
6
8
0
7
0
0
0
10
170
        Note:   1 : Thickner
                2 : Digestion tank
                3 : Sludge elutriation tank
                4 : Sludge storage tank
                                     17

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Table 2-5 Comparison of Solid Concentration between Digested and Raw Sludge
Solid concentration
(%)
0- 1
1 ~ 2
2- 3
3- 4
4- 5
5-6
6- 7
7- 8
8- 9
9-10
10-15
15-20
20-25
25-
No data
Total
Digestion
0
1
10
17
21
17
8
6
j
1
5
0
0
0
9
98
No-digestion
0
0
9
10
13
14
3
7
0
0
2
1
1
0
12
72
Total
0
1
19
27
34
31
11
13
3
1
7
1
1
0
21
170
                               -  18  -

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Table 2-6  Cake Solid Concentration after Dewatering
\Type of dewatering
x__ machine
Cake ^~~~~~~~-~-~-__^
solid concentration^
(%) \
0-15
15-20
20-25
25-30
30-35
35-40
40-45
45-50
50-55
55 ~
No data
Total
Vacuum filter
0
10
44
39
14
8
0
1
0
1
18
135
Centrifuge
0
3
6
6
2
0
0
0
0
0
4
21
Filter press
0
1
1
0
1
3
0
3
1
2
1
13
Others
0
1
0
0
0
0
0
0
0
0
0
1
Total
0
15
51
45
17
11
0
4
1
3
23
170
                      19

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                                                        Table 2-7  Dose of Fe3+and Ca2+in Vacuum Filter
^~-\_Ca^+dose (%)
Fe3+dose (%T"^\^
0~ 5
5-10
10-15
15-20
20-25
25-30
30-40
40-50
50-
Total
0-10
19
1







20
10-20
10
13
1






24
20-30
6
11
5






22
30~40
2
10
5
2
1
2



22
40-50
2
1
5






8
50-60
2
2
2

2
1

1

10
60-70









0
70 - 80



1





1
80-90
1





1


2
90 - 100









-0
100-




1



1
2
Total
42
38
18
3
4
3
1
1
1
111
o
 :
                                No data 24

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                                             Table 2-8  Relationship between Solid Concentration and Yield of Vacuum Filter
N. Actual Yield, ^
c r>^esi§n YielrT
Solid x.
Conc.C^rN^
0- 1
1 ~ 2
2- 3
3~ 4
4- 5
5- 6
6- 7
7- 8
8~ 9
9-10
10-
Total
0-10


1


1
1




3
10-20



1
1


2



4
20-30


1
2
4


1



8
30-40


1
3

2
1



1
8
40-50


5
2
2
5
1



1
16
50-60



4
4


1



9
60-70


1
3
5
2




1
12
70-80


1
1
2
3
2




9
80-90




1
1
1
2


2
7
90 - 100



1
1
1

1



4
100-

1
1
3
4
8
2
4
2
1
2
28
Total
0
1
11
20
24
23
8
11
2
1
7
108
 I
to
                                 No data 27

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INJ
tNj
                        Sludge volume produced (m3)
                        4000
                                                50000
                                                                                 Correlation coefncienl. 0.6105
   300000
Capacity (in3)
                                                                Fig. 2-1   Relationship Between Sludge Volume and Capacity     (Vacuum  filter)

-------
 I
to
                                                                                                       »      Vacuum filter
                                                                                                              Filter press
                                                                                                              Centrifuge
                                                   Fig. 2-2  Relationship Between Capacity and Power Consumption

-------
 I

1NJ
                                                                                                                   *  Vacuum filter
                                                                                                                  4  Filter press
                                                                                                                  0   Centrifuge
                                                                 1000                                  ,000

                                             Fig. 2-3  Relationship Between Sludge Volume and Power Consumption
          3000

Sludge volume produced (m3 )

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CHAPTER 3
SEWAGE  SLUDGE  TREATMENT  AND  DISPOSAL  AS  PRACTICED   IN
YOKOHAMA  CITY
-"RECLAMATION  TO  AGRICULTURAL   LAND  AND  GREEN   FIELD"
   PROGRAM -
                              CONTENTS
1.  Present Status of Sewage Sludge Treatment/Disposal	26
2.  Problems Associated with Sewage Sludge Disposal  	28
3.  "Reclamation to Agricultural Land and Green Field" Program	28
   3.1 Size of "Reclamation to Agricultural Land and Green Field" Program  . .29
   3.2 Sludge Dryer Installation	29
   3.3 Outline of Installation   	31
   3.4 Construction and Operation/Maintenance Costs	31
   3.5 Properties of Dried Sludge	32
                                    25

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Sewage Sludge Treatment and Disposal as Practiced in Yokohama City
— "Reclamation to Agricultural Land and Green Field" Program —
1.    PRESENT STATUS OF SEWAGE SLUDGE TREATMENT/DISPOSAL
     In  the  sewerage  plan  of  Yokohama  City, constructing ten sewage treatment
plants in nine treatment districts is planned, and so far five are already in service. At
these treatment  facilities,  secondary  treatment  by  activated  sludge process  is
performed, and the sludge produced from these facilities today amount to, in terms
of concentrated sludge (moisture content 96%),  roughly 600,000  cubic  meters
annually. Treatment  and disposal  methods practised are: (1)  unaerobic  digestion
process at two plants and wet air oxidation at one plant,  followed by (2) dehydration
in both cases, and (3) disposed to, in most part, dumping  yards of the City as land fill.
     Characteristics of sludge cakes: those treated by unaerobic digestion process has
a moisture content of  70  to  75% (carbide slurry and  ferric chloride added) with
volatile matter 25 to 30%; those by wet air oxidation has a moisture content of about
40% with volatile matter 10  to 15%.
     Given in Fig. 3 — 1 is the outline of sewage sludge treatment/disposal process and
major sludge treatment facilities.
                                   - 26

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Fig. 3-1 Sewage sludge treatment and disposal process
 Concentration -
-•- Unaerobic digestion •
                      • Dosage	
                      (cabide slurry
                      ferric chloride)
                      •Wet air oxidation -
Elutriation -
-Dosage	—Vacuum dehydration -
 (cabide slurry
 ferric chloride)
                                                                                                                    Drying
                                                                         Dosage —
                                                                         (polymer)
                                                                        • Centrifugal -
                                                                         dehydration
                                                                   • Press dehydration -
Reclamation to agricultural
land and green field
                                                                                                                               • Land fill

                                                                                                                                Reclamation to agricultural
                                                                                                                                land and green field
                                                                          Land fill

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2.   PROBLEMS ASSOCIATED WITH SEWAGE SLUDGE DISPOSAL
     The volume of sewage sludge produced in Yokohama City roughly doubled in
three years  since 1970. Sludge cakes produced presently amounts to 40,000 cubic
meters annually, and it is estimated to increase by tenfold, or 400,000 m3, by 1985.
     This sludge  is now,  as  it was  described earlier, dumped over dumping yards
within the  City, however,  due  to  rapid  expansion of dwelling districts,  distant
dumping yards are being sought, and with increased traffic conditions within the City,
its  transportation is found more  and more difficult these days. Moreover, it is very
difficult  to find new inland dumping yards today. And at the present dumping yards,
disposed cakes tend to become  a  very soft  mud as they  quickly  absorb  a large
quantity of water,  posing a troublesome problem to proper land  fill operations.
Difficulties in handling, bad-smelling and leachate out of the sludge cake are among
the associated problems for which we are under the pressure to find other means of
disposal.
3.   "RECLAMATION  TO  AGRICULTURAL   LAND  AND   GREEN FIELD"
     PROGRAM
     It is the principal rule to follow, in its end, that all sewage sludge is returned to
the  ground  by accomplishing it  in  harmony with the Nature's  cyclic process of
materials. It is desirable, therefore, to dispose sewage sludge to the ground or to the
ocean, in a manner that will not disturb, or helps the ecosystem of the  Nature.
     For a coastal  city  like Yokohama, although we cannot  choose but to rely on
returning it to the  ocean and reclaiming a foreshore while concentrating our efforts
on  finding  inland  dumping yards,  we  must work to  establish  a disposal scheme
primarily based on  returning to the  ground  and reclamation to agricultural and green
field, as a more essential solution to this problem.
     Since  sewage sludge contains nitrogen  and phosphorus and is rich with organic
matter, unlike chemical fertilizers, when it is  returned  to the soil, its benefit is not
limited to serving as an enrichener, but to aid in producing an environment necessary
for the growth of bacteria in the  soil, subsequently creating an airy soil construction
desirable for vegitation with good retention of moisture.
     A three  year  study,  from  1971  to 1974, that Yokohama City conducted in
cooperation with  the  Tokyo University of  Education  reveals that  it  could  be  a
hopeful  fertilizer with about  the same dressing effectiveness as matured compost,
whereas  it  is  slow  acting to dry field rice  plant  and barley when compared with
chemical fertilizers.
     As for its dressing effectiveness  to cyclamen, a garden plant, it is found to be
much  the  same  as that  of the soil  customarily used, it is  a slow-acting  but
long-standing  fertilizer.  When sludge  is  used  to  lawn  soil, it is found  that lawn's
growth in height and in the area of  its leaves increased with the increase of its sludge
appliction.
     For acceptable application of sewage sludge to the soil, ease of handling, storage
and  transportation,  and freedom  from  discomfort are required. Pathogenic bacteria
and weed seeds must be sterilized, too.
     For these reasons, it  is desirable that, following dehydration  processing, sludge
be  dried  by dryers to reduce its moisture  content further until  granular sludge is
obtained.
     In  Yokohama  City,  operational  sludge  dryers were installed in the  Nambu
Sewage Treatment Plant in  1973 and  1974 as part of promoting "the reclamation to
agricultural land and green field" program.
                                    -  28 -

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3.1   SIZE  OF  "RECLAMATION TO  AGRICULTURAL  LAND  AND  GREEN
     FIELD" PROGRAM
     Before sludge reclamation to agricultural land and green field is carried out, such
factors as secondary public nuisance by heavy metals, or plants' absorption of heavy
metals and their accumulation  in  the  soil,  must  be  thoroughly  studied. Sludge
application therefore should be carefully selected, and for the time being, limiting its
application to greenyard of parks in the  City,  an annual desposition of 2,600 tons of
dry sludge (equivalent to roughly  24% of  the sludge cakes produced) is planned.
3.2  SLUDGE DRYER INSTALLATION
     Digested sludge is added with polymer  and then  dehydrated by a centrifuge
before it is  fed into the  sludge dryer system.
     The project size  of installation:  two sludge dryer systems to be  run  on a
six-hour-a-day basis, each with a  capacity of 1,300 tons of dried cludge output. One
system  is to  be installed initially. If the installation is operated on a full scale,  it
would have the capability of producing  some 10,000 tons of dried  sludge annually.
The drying system is schematically represented in Fig. 3-2.
                                     29

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            Fig. 3-2 Flow diagram of sludge dryer
u-i
o
                                                             Cyclone
                                                             80% dust catch
Scrubber
90% dust catch
                    Deodoreizer
                    Temp  :  700° C
                    Fuel   :  Digestergas 743Nm3/hr
                             (Kerosene 530«/hr)
Exhaust stack
Gas temp. 700°C
Height 15m
                                                         Dewatered sludge
                                                         strage tank
                                                                                                                                  Truck loader
                                                                                                       Measuring & pouring machine
                                                    Capacity  :  3,500 Kg/hr (Cake TS 25%)
                                                               1,006 Kg/hr (Dried Cake TS 13%)
                                                    Fuel     :  Digester gas 372 Nm3 /hr
                                                               (Kerosene 287 1/hr)

-------
3.3  OUTLINE OF INSTALLATION
     The drying system consists essentially of the following four elements:
a)   Sludge Feeder
     Dehydrated sludge is continuously fed to the dryer with a variable-speed screw
conveyor in a batch process.
(b)  Dryer
     While moving slowly in the axial direction, sludge is exposed to heated air of
about 900° C blown in the same direction as the drum rotates slowly. Temperatures
within the drum  are so controlled  that it is  approximately  900°C at the entrance;
about 1 20° C at the outlet.
     Sludge is scraped upward to the upper part of the drum with blades attached on
the inner  wall  of  the drum,  and is crushed by rotating  rods as it falls off from the
upper part of  the drum.  By this repeated process  of crushing,  sludge gets  greater
surface area while moving from one end to the other in the drum, and it contacts with
the hot air for  about 40 minutes. Obtained is granular sludge with a moisture content
of about 13%.
     For  the best possible utilization of energy,  primarily digestion gas is  used as
fuel-another benefit of eliminating air pollution by other fuels.
(c)  Dry Sludge Storage/Bagging Unit
     An automatic measuring/bagging machine packages dry sludge in polyethylene
bags in a 20 kg batch.
(d)  Exhaust Gas Clarifyer
     Cyclone dust catchers and  a scrubber are arranged  in series. With 98% of dust
caught by  this  arrangement,  the dust content of air released to  the  atmosphere is
0.17 g/Nm3, or 60% below the 0.4 g/Nm3 requirement specified under the Kanagawa
Prefecture Public Nuisance Prevention Act.
     Deodorization of exhaust gas is accomplished through oxidation-decomposition
by heating it  to about 700° C. The deodorization furnace temperature is controlled to
700°C. At this temperature, nitrogen oxides generation is reduced to a minimum.
     Exhaust gas  is free of sulfur oxides  when digestion  gas is used. Their discharge
with the use of kerosene is 2.245 m3/h, 50% below the 4.1 Nm3/h  requirement.
     Calories  necessary for the deodorization are: with digestion gas, 4,454,000 kCal
per hour with a fuel consumption of 743 Nm3 per hour; with kerosene, 530 liters per
hour.
3.4  CONSTRUCTION AND OPERATION/MAINTENANCE COSTS
     Listed  below is  the breakdown of construction  cost of  the sludge  dryer
installation:
     Dryer system                165,900,000 yen
     Electrical system               80,400,000 yen
     Buildings                   108,384,000 yen
     Miscellaneous                  1,390,000 yen
     Total                       356,074,000 yen
     Annual cost  for operating the dryer  installation  on a  3-personnel  operator,
6-daytime-hour run basis is estimated as follows:
     Personnel cost                 9,000,000 yen
     Electricity cost                 2,202,000 yen
     Repairs, expendables            6,900,000 yen
     Equipment lease (fork trucks)   1,200,000 yen
     Depreciation of installation     15,027,000 yen
                                     31

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     Fuel cost                             0 yen
     Total                        34,329,000 yen
     With  an annual  dried sludge  production of  1,300 tons, the dehydrated sludge
costs about 7,600 yen per ton.
3.5  PROPERTIES OF DRIED SLUDGE
     Composition of  sludge before and after drying processing as a fertilizer, is given
in Tables 3 — 1. You may notice that components  remain much the  same before and
after processing in the dryer. Dry sludge generally  has a moisture content of 5 to 16%
with granular sizes ranging between 1.0 and 3.3 millimeters in diameter.
Tables 3—1 Compositon of sludge before and after drying processing as a fertilizer
Item
Total Solids
Volatile Solids
Phosphorus (P2 O5 )
Patassium (K2 O)
Calcium (CaO)
Magnesium (MgO)
Nitrogen (Kjeldahl)
pH
Dehydrated Sludge
23.8%
39.7
3.2
0.77
2.9
1.0
3.3
7.45
Dried Sludge
90.0%
35.8
3.1
0.75
3.0
1.0
2.9
7.17
Note
Weight % of Sludge
Weight % of Solid
Weight % of Solid
Weight % of Solid
Weight % of Solid
Weight % of Solid
Weight % of Solid
Weight % of Solid
                                      32

-------
      CHAPTER 4.  THE TREATMENT AND DISPOSAL OF SLUDGE AT
                   TOBA TREATMENT PLANT

4.1  Introduction	34
4.2  Outline of Sludge Treatment Facilities	
4.3  Operation Data of Sludge Treatment Facilities	36
       Solids Balance at Each Treatment Process	36
       Thickening Tanks	38
       Digestion Tanks	39
       Dewatering Facilities	40
       Incinerators	'	41
4.4  Some Considerations on Toxic Substances and Heavy Metals in
    Disposing Sludge	42
       Toxic Substances in the Exhaust Gas from the Incinerators and the
       Countermeasures	  42
       Effluence Test of Toxic Substances and Others from Ash	42
4.5  Researches on Sludge  Ash for its Reuse	    45
       Utilization for Soil Conditioners	45
       Use as a Material for Road Construction	45
                               - 33  -

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4.1  INTRODUCTION
     Kyoto is an inland city located on the midstream of the Yodo River. On the
lower reaches of the river there is a group of cities centering around  Osaka, and
the river is the only source of water for approximately ten million people in those
cities.  The  river water,  therefore,  is  widely  used  for drinking, farming,  and
industries.
     Aiming  to  ameliorate  the  life  environment of the  citizens  and  to  prevent
water pollution  of  the Yodo  river,  the City of Kyoto has been endeavoring to
construct its  sewerage  system. As of March 1975, the city's sewer system covers
45% of the urbanized  area of the city. That is, 48% of the total citizens share in
the benefit of the system. By the year 1985 the system is to cover the whole of
the urbanized area of the city.
     At present  the sewage  is treated by three plants, namely Toba, Kisshoin, and
Fushimi Plant. (Table 4.1) Of the three, the Toba Plant is the biggest. The present
conditions of the sludge treatment at Toba Plant are described below.
                  Table 4.1  Present Conditions of the Three Plants
Name of
Plant
Toba

Kisshoin
Fushimi
Treat't
Capacity
m3/d
570,000

92,900
55,000
Qty. of
Inflow
m3/d
388,400

94,300
22,100
Treat't
Process
Activated
Sludge
Process
Activated
Sludge
Process
Activated
Sludge
Process
Sludge Treatment Process
Thickening- Anae robic Dige st ion- Vacuum
Filtration -^ Incineration-Reclamation
or Thickening-Vacuum Filtration-!
Pumping to Toba Plant
Thickening-Vacuum Filtration- Transport
to Toba Plant
    Note: The quantities listed above are the average inflow at the time of dry weather during
         the period from April 1974 to March 1975
4.2  OUTLINE OF SLUDGE TREATMENT FACILITIES
     At the Toba Plant, not only the sludge produced at  the Plant but the night
soil  brought  into  the  digestion tanks and the sludge  pumped from the Kisshoin
Plant are treated.  As shown by Figure 4.1, before the sludge becomes ash and is
used  for  landfill,  it is digested, dewatered  and  incinerated,  or  raw  sludge  is
dewatered and incinerated. The sludge cake dewatered  at the Fushimi Plant is also
transported  to  the Toba Plant,  where  it  is  incinerated.  Thus  all  the sludge
produced  at  those three plants  is in  the ultimate treated and disposed of at the
Toba Plant.
     Table 4.2 shows an outline of the sludge treatment facilities.
                                     34  -

-------
               Figure 4.1   Flow Diagram of Sludge Treatment


i Raw
Excess 	
1 Sludge
1
1
I
1
Sludge fr.
•Gsshoin P.
Night Soil
Collected

i


L
i
Digestion Elutriation


)
Methane Gas
1

Desulfurizerl — 5-!rd;>, -•*•
	 Tank
uewaieieu
Cakes fr.
Fushimi P.

i
Vacuum V |

~S Filter -Hlncinerator| {
1
1
I
1
1
Utilization for Fuel |
_l
                                                                      • Landfill
Table 4.2  Outline of the Sludge Treatment Facilities
 1. Sludge Thickening Tanks

Type
Diameter
Water Depth at Wall
Number of Tanks
Capacity, Each Tank
I
Circular Tank
20.0m
3.0m
2
966m3
n
Square Tank
17.0m x 17.0m
3.6m
2
1,160m3
ffl
IV
Circular Tank
20.0m
3.0m
4
942m3
 2.  Sludge Digestion Tanks (Two Stage Digestion)

Type
Diameter
; Water Depth at Wall
Water Depth at Center
Heating System
Agitating System
Number of Primary
Digestion Tanks
Number of Secondary
Digestion Tanks
Capacity, Each Tank
Temperature
Detention Period
I
n
ra
IV
Cylindrical. Tank with Cone Bottom and Fixed Cover
25.0m
5.2m
9.2m
25.0m
8.2m
ll.lm
Heat Exchanger
25.0m
8.2m
ll.lm
Steam Blowing
Gas Agitator
1
1
3, 600m J
3,090m3
30°C
30 days
2
2
3
1
3
1
4,400m3
30°C
30 days
22.5 days
                                  - 35  -

-------
  3.  Vacuum Filters

Type
Diameter of Drum
Length of Drum
Surface Area of Filter
Rate of Filtration
Number Installed
i n
Belt Filter
3.5m
4.2m
47m2
17.5 kg dry solid/m2
hr
8 12
  4.  Incinerators
Type
Outside Diameter
Height
Burning Temperature
Number of Stages
Capacity, Each
Number Installed
Multiple-Hearth Type
4.35m
10.04m
5.10m
1 1 .34m
6.78m
12.35m
800°C
8
60t sludge cake/day
2
1
150t sludge cake /day
3
4.3  OPERATION DATA OF SLUDGE TREATMENT FACILITIES

4.3.1  SOLIDS BALANCE AT EACH TREATMENT PROCESS
     The  average daily figures of solids balance at  each treatment process at  the
Toba Plant during the  period  from April 1974  to  March  1975 are shown by
Figures 4.2, 4.3, and 4.4. The suspended solids in the  inflowing sewage is 57 tons.
Through  the  sewage  treatment  process, 14.7  tons of excess activated sludge is
synthesized from the soluble  matter. Further the solids in the wastewater to be
returned to the sewage  treatment facilities from the sludge treatment facilities are
added to it. Thus  the  total quantity of the sludge  solids  that  are sent to  the
thickening tanks becomes 127.3  tons.
     Besides the aforementioned, 9 tons of sludge  solids is sent to the thickening
tanks from the Kisshoin Plant, 6.5  tons of solids in the night soil is thrown into
the digestion  tanks, and  2.3 tons of dewatered cakes is sent to  the incinerators
from  the  Fushimi Plant.  Thus all the  sludge  produced  at those  three plants is
treated and disposed of by the Toba Plant.
     As shown  by  Figure 4.4,  altogether  136.3  tons of solids  is  sent to  the
thickening tanks, and out of the 126 tons efflux 57.2 tons is  fed to the digestion
tanks and the  other.68.8 tons is sent to the dewatering facilities.  Of the sludge
solids fed to the digestion tanks, 12.5 tons is gasified and other 30.5 tons is sent
to the  dewatering  facilities as  digested sludge.  By  the  incinerators, altogether
360.4 tons of  dewatered cakes  is incinerated  and  48.1 tons  of ash is produced.
The 360.4 tons of cakes consist of 261.6  tons of raw sludge cakes, 88.8 tons of
digested sludge cakes, and 10 tons of cakes sent from  the Fushimi Plant.
     The  solids  in the wastewater  from the sludge treatment facilities are 10.3
tons from the thickening tanks, 20.7 tons from the digestion tanks, and 29.6 tons
from the dewatering facilities.
                                   -  36 -

-------
Figure 4.2   BOD and SS Balance at the Sewage Treatment Process

                                  Inflowing Sewage
                                  SS
                                  BOD
                                      "57.0 t/dl
                                      85.0~17dl
                                  SS
                                      117.6 t/d
                                  BOD   117.0 t/d
fr. Sludge Treatment System
          Excess Sludge
                                      I
                               Primary Sedimentation
                                      Tank
                                                             SS|  127.3 t/d|
SS
BOD
35.3 t/d
52.7 t/d
Removal
70%
55%
                                                            to Sludge Treat't System
                                   Aeration Tank
                                                    ~~|
                             - Final Sedimentation Tank I
                                           "
SS
BOD
5.0 t/d
6.0 t/d
Removal
86%
89%
Total
Removal
91%
93%
                                    Effluence
 Figure 4.3  Solids Balance at Toba Plant
                             Inflowing Sewage
                                    II
                               157.0 t/d |
    I
Wastewater
(60.6 t/d|
                          Sewage Treatment Facilities
                               Raw Sludge
                                   I
                               |127.3  t/d|


V V
Sludge Treatment Facilities


                               Incineration
                                   I
                              [72.0 t/dl
                                Landfill
                                                            Raw Sludge fr.
                                                            Kisshoin Plant
                                                              Night Soil
                                                              Collected
                                                            Digested & Gasified
                                                            J12.5  t/d|--— >

                                                            Dewatered Cakes
                                                            fr. Fushimi Plant
                                        37  -

-------
 Figure 4.4  Solids Balance at the Sludge Treatment Process
toTobaPlant
[Total wast ewater
TobaPlant
1127.3 t/d|
|60.6 t/d] 13&.J
i
Overflow



u, -1 1 n 1 t /H 1 -'
r |iu.j i/u|
1
i
'Supernatant
1
'Supernatant
1 L_
1
'Filtrate etc.
rl!7 6 t/dl- T
126.0
1
140.3 t/d]

t/d

Kisshoin Plant
19.0 t/dl

ng Tank

"t/d]



116.9 t/d|
Night Soil
Collected
16.5 t/dl

|23.4 t/d|

Digestion
Tank
(Sewage Sludge)

|20.4 t/d|
	
Gasified
i
Digestio
	 (Sewage
Night Sc
Gasified
H4/7 t/dh-
I
n Tank
Sludge & U
il)
Qai "t/dj
i 168.8 t/dl
1
i
1 i 	

30.5

t/d|

. 	 1 Elutriation Tank
i
[ -- Storage Tank |-- 	
I r-J
i



Storage Tank]


i L -j Vacuum Filter fl | ' 	 ] Vacuum Filter I| Fi
I Filtrate etc. '
112.0 t/d 	 '
Solids
Cakes

56.8 t/d Solid
261.6 t/d Cake


s 12.9 t/d So
5 88.8 t/d Ca
ishimi Plant
lids 2.3 t/d
kes 10.0 t/d
Solids
Cakes
72.0 t/d
360.4 t/d
                                  | Incinerator |
                                Ash |    48.1 t/d |
                                      T
                                    Landfill
4.3.2  THICKENING TANKS
     The thickening tanks  are divided into four groups. The operation data of the
tanks are shown by  Table 4.3.  The  average concentration of the solids  in  the
sludge coming from the primary sedimentation tanks  is 1.1 to 1.5%. The average
concentration of the solids in the thickened  sludge  is 2.1 to 2.6%. Figure  4.5
shows the relationship between the initial sludge concentration and the rate of the
concentration increase.  It  shows how poor  the thickening efficiency is.  At  the
Toba Plant the efficiency is gradually lowering in recent years.
                                      38

-------
        Figure 4.5  Relationship between the Initial Sludge Concentration and
                    the Rate of the Concentration Increase
              SJ
              a
              o
              C
              d
              o
              o
              O
              u
              •
n \ (
o XT



o


DD\p A
A

1


n


*°
*\oR
V o
oc
\
A

^










:
•
X-

x
A \
•
0


0


Group


I
• Group n
A Group m
a Group IV







\
\


















                01234
                          Initial Sludge Concentration (%)

 Table 4.3  Operation Data of Sludge Thickeners
                                                                1000
                                                                500
100
                                                                50
                                                               10
Gr.
I
n
III
IV
Total
Raw Sludge
Solids
t/d
35.6
39.7
35.4
25.6
136.3
Cone.
%
1.1
1.5
1.4
1.4

Thick Sludge
Solids
t/d
34.0
36.7
30.9
24.4
126.0
Cone.
%
2.6
2.5
2.1
2.1

Effluent
Solids
t/d
1.6
3.0
4.5
1.2
10.3
TS
mg/1
474
506
1,530
610

BOD
mg/1
185
152
579
176

Solids
Loading
kg/m2 -d
54.2
68.7
56.8
40.3

Overflow
Rate
m3/rn2-d
8.5
13.3
8.2
5.3

Detent.
Period
hrs.
8.9
7.3
9.8
15.0

4.3.3  DIGESTION TANKS
     The  digestion tanks are divided into four groups. Every one of those tanks is
equipped  with a  heating system  and a gas  agitator.  The operation data of  the
digestion  tanks are shown  by Table  4.4.  It must be  noted that the  digestion
conditions of  Group  III  tanks  are  different from  the others,  because in  these
Group III tanks night soil is mixed with sewage sludge before  digestion.
                                    - 39  -

-------
     At Group IV tanks the heating is  done in the tanks with steam  blowing,
while the tanks  of  the other Groups employ  the  heating by the duplex pipe
counter flow heat exchangers. The temperature in the tank is kept at 27  to 30°C.
The gas agitator is intermittently operated when sludge is fed in.
     The  digestion period  is  23  to  30  days.  The load of  volatile  solids  is
controlled 1.1 to  1.6 kg/m3-d.
     It is  previously  mentioned that the concentration of the sludge fed in is low.
The same of the  digested sludge is also low being only 3.0 to 3.2%. The volatile
acids in the  digested sludge at Groups I, II, and IV are 150  to 200 mg/1 and  at
Group  III it  is 400 mg/1. The alkalinity in Groups I, II, and IV is  1,600  to 1,700
mg/1, while at Group III it is 3,800 mg/1. The BOD of the supernatant is  1,200  to
2,300 mg/1. In any of those tanks scum can hardly be found.
     The  digestion rate is  low  at every tank being  approximately 30%.  At these
tanks,  altogether approximately 12.5 tons of volatile solids is decomposed, and
approximately  12,000 m3  of sludge  gas is produced per day. After desulfurized,
approximately 4,500  m3  of the  sludge gas is  utilized  for fuel for the  digestion
tank heating, and  other  7,500  m3   is  used  as  supplementary  fuel of sludge
incinerators.
 Table 4.4  Operation Data of Sludge Digestion Tanks
Gr.\
I " 1
II
III
IV
Total
Feeding Sludge
Solids
t/d
7.6
15.4
16.9
6.5
17.3
63.7
Cone.
%
2.6
2.7
2.5

Volatile
Solids
%
65.2
70.5
65.9

Digested Sludge
Solids
t/d
4.5
9.5
10.1
6.4
30.5
Cone.
%
3.0
3.2
3.0
3.0

Volatile
Solids
%
58.3
57.4
59.3
57.4

pH
7.2
7.2
7.6
7.1

Alkali.
mg/1
1,649
1,706
3,828
1,604

Volatile
Acids
mg/1
196
149
396
165

Gr\
I
II
III
IV
Total
Supernatant
Solids
t/d
1.7
3.0
8.6
7.4
20.7
PH
7.3
7.3
7.7
7.3

TS
mg/1
6,338
5,347
1 1 ,249
10,588

BOD
mg/1
1,519
1,159
2,311
2,163

Digest.
Temper.
°C
26.8
27.7
28.8
30.0

Digest.
Period.
days
27
37
23
30

Volatile
Solids
Loading
kg/m3-d
1.5
1.2
1.1
1.6

Digest.
Rate
%
29
29
29
31

Gasif.
Solids
t/d
1.4
2.9
4.7
3.5
12.5
4.3.4 DEWATERING  FACILITIES
     For sludge  dewatering, the  vacuum filters  of  the  belt  type have  been
employed.  Eight  filters of Group  I dewater digested  sludge and twelve filters of
                                 - 40 -

-------
Group II dewater raw sludge. The operation data of those dewatering facilities are
shown by Table 4.5.
     The concentration of the digested sludge to be dewatered is  approximately
3%,  while  the same  of raw sludge is  approximately 2%. The alkalinity  of the
digested sludge is 1,600  to 3,800 mg/1, while the same of the elutriated sludge is
approximately  600  mg/1. The  elutriation of the digested  sludge is done by two
stage counter flow elutriation tank. The alkalinity of raw sludge is 460 mg/1.
     As coagulants, ferric chloride (FeQ3) and slaked lime (Ca(OH)2) have  been
used. The  chemical dosages  to  the sludge are 9.8% of FeCl3  and  46.5%  of
Ca(OH)2 for Group I, and 4.9% of FeCl3 and 23.2% of Ca(OH)2 for Group II.
     The filter yield rate is 5.3 kg/m2.hr at Group I  and 12.3  kg/m2.hr at Group
II. The moisture content of the dewatered cakes is 77.1% at Group I and 72.5%
at Group II.  At Group I the filter yield rate  is low  and the  moisture content is
high. It is because the proper vacuum can not be retained  owing to the following
two  reasons.  Firstly the  concentration of sludge is  low and hair cracks are caused
in the cakes on the filter medium at the time of dewatering due to the smallness
of the quantity of fibrous materials.  Secondly the  efficiency  of the facilities has
been degraded due to superannuation.
     The filter yield rate and the  moisture content of the cakes are  closely  related
with the sludge concentration. The low concentration of the sludge has caused the
high dosage of the coagulants and the poor dewatering efficiency.

 Table 4.5  Operation Data of Sludge Dewatering Facilities
Gr.
I
II
Total
Feeding Sludge
Solids
t/d
30.5
68.8
99.3
Cone.
%
3.1
2.2

Alkali.
mg/1
2,392
....

Elutr.
Sludge
PH
6.9
6.5

Alkali.
mg/1
607
461

Dewatered
Cakes
Qty
t/d
88.8
261.6
350.4
Solids.
t/d
12.9
56.8
69.7
Moist
Cont.%
77.1
72.5

FeCl3
%
9.8
4.9

Ca(OH)2
%
46.5
23.2

Filt.
Yield
Rate
kg/m2 -hr
5.3
12.3

4.3.5  INCINERATORS
     All  the  dewatered  cakes  are  incinerated.   The  incinerators  are  the
multiple-hearth  type.  Three  of the  six incinerators incinerate 60 tons per  day
each, while the other three do 150 tons each.
     The  calorific value of dewatered  cakes  is 1,900  to  2,500 kcal/kg. As  the
supplementary  fuel,  heavy oil  and sludge gas are utilized. For prevention  of air
pollution, low  sulfureous heavy oil  (sulfur  content  less than  0.8% and in winter
the same  less than 0.5%) is used,  and 35 to 40 liters of the  oil is consumed per
ton  of  dewatered cakes.  In  case of  digestion  gas,  whose  calorific value is  5,600
kcal/m3,  50  to 70m3 of gas is consumed  per ton of dewatered cakes.
     The  moisture content of the  dewatered cakes  is 72 to 77%.  If the moisture
content is less  than 75%, the incineration efficiency is satisfactory and the con-
sumption  of supplementary fuel is  comparatively small.  If  the moisture content is
over  75%, it is  very hard to keep the incinerator at the proper temperature.
Especially the low temperature at the third and fourth stages, pre-heating stages,
causes imperfect combustion.  Hence poor incineration efficiency.
                                   -  41 -

-------
     For the  maintenance of incinerators, wear and corrosion of fans, rabble arms
and  rabble teeth  in  the  furnace  and damage of bricks at the hearth have to  be
checked from time to time.

4.4  SOME  CONSIDERATIONS  ON  TOXIC  SUBSTANCES   AND  HEAVY
     METALS IN  DISPOSING SLUDGE
     As of 1975 approximately 400 tons of dewatered cakes is incinerated  and  50
tons of ash has to be disposed of per day. As the sewerage system of the city is
to  be  expanded, a remarkable  increase in  quantity  of  sludge  and  ash  is
anticipated. Consequently  in  the sludge  incineration and  ultimate  disposal,  we
have to use every discretion for behavior of the toxic substances and heavy metals
contained in the sludge and ash.
     As shown by Table  4.6, the concentrations of toxic substances  and heavy
metal in the  inflowing sewage and the effluent  are very low.  However, they  tend
to be adsorbed and  concentrated in the sludge. Therefore,  it has to be carefully
examined whether they pollute the air or  not when incinerated and whether  they
cause pollution of ground  water or not after tne ash is used  for landfill.

4.4.1  TOXIC SUBSTANCES IN  THE EXHAUST GAS FROM INCINERATORS
      AND THE COUNTERMEASURES
     The  concentrations  of the  toxic substances  and  heavy  metals  in the
dewatered cakes are not uniform.  An example of analytical data is shown in Table
4.6.  The concentration of iron is especially high, because ferric chloride is added
for the coagulation.
     The exhaust gas from the incinerators is controlled by laws and regulations.
That  is,  the  air  pollution prevention law and  the  public nuisance prevention
regulation of Kyoto  Prefecture regulate particulate matter and sulfur oxides. The
offensive odor  prevention law restrains nasty smell,  such as ammonia, hydrogen
sulfide, and trimethylamine.
     The exhaust gas is treated by the scrubber of wet cyclone type.  The analysis
table of  the  exhaust gas  before  and after  the scrubber  is  Table  4.7.  The
concentrations of the particulate matter, hydrogen sulfide and trimethylamine  at
the outlet of the scrubber are within  the standards.
     No  laws  nor regulations  control the toxicants  and  heavy metals from the
sludge  incinerators.   However,  compared  with  the  standards  set  for other
incinerators,  some  of the  figures  of  the sludge incinerators  are  beyond the
standards.  It  means  that  the  treatment  by  the single  stage  scrubber  is not
satisfactory.
     Therefore, remodeling of the incinerators is now being considered for the
perfect treatment of exhaust gas.  According to the plan, a cooling tower with two
stage elutriation  system, a  tower  for the  elimination by  means  of sodium
haydroxide solution  and ferrous sulfate solution, and  an electric dust  collector are
to be  installed next  to  the existing scrubber so that particulate matter, sulfur
oxides,  nasty smell,  toxic substances,  and heavy metals  as well as white  smoke
may be  eliminated more effectively.

4.4.2   EFFLUENCE TEST OF TOXIC SUBSTANCES AND  OTHERS FROM ASH
     The concentrations of toxic  materials and heavy metals in the ash  are  shown
                                    42

-------
 Table 4.6  Toxic Substances and Heavy Metals in Various Samples
                                                                                     (ppm)

Mercury
Cadmium
Lead
Organic
Phosphorus
Hexavalent
Chromium
Arsenic
Cyanide
Alkylmercury
Copper
Iron
Zinc
, Manganese
j Nickel
Chromium
Inflowing Sewage
Toba
Kjsshoin
0.0020 : 0.0017
0.000 i 0.000
0.00
0.00
0.00
0.001
0.06
0.0000
0.15
0.40
0.54
0.05
0.05
0.07
0.00
0.00
0.00
0.005
0.04
0.0000
0.23
0,34
0.42
0.09
0.03
0.06
Fushimi
0.0003
0.000
0.00
0.00
0.00
0.001.
0.00
0.0000
0.03
0.24
0.09
0.05
0.00
0.00
Effluent
Toba
0.0001
0.000
0.00
0.00
0.00
0.001
0.01
0.0000
0.01
0.03
0.07
0.04
0.01
0.01
Kisshoin
0.0003
0.000
0.00
0.00
0.00
0.002
0.02
0.0000
0.06
0.12
0.13
0.06
0.01
0.02
Fushimi
0.0001
0.000
0.00
0.00
0.00
0.001
0.01
0.0000
0.01
0.03
0.05
0.00
0.00
0.00
Dewalered Cake
Toba
5.25
4.72
105
0.00

9.73
0.51

956
46,800
1,850
486
138
497
Fushimi
2.22
1.82
160
0.00

10.10
0.15

250
24,500
780
152
48
65
Ash
0.077
3.7
20.4


14.4
0.72

897
52,600
2,921
1,035
250
548
Ash Solution*
Aver.
0.0000
0.000
0.04
0.00
0.05
0.011
0.01

0.03
1.11
0.09
0.01
0.0 1
0.45
Max.
0.0000
0.000
0.22
0.00
0.42
0.053
0.02

0.14,
6.05
0.80
0.03
0.05
1.90
Min.
0.0000
0.000
0.00
0.00
0.00
0.000
0.00

0.00
0.00
0.00
0.00
0.00
0.00
Standards
(less than)
0.005
0.3
3
1
1.5
1.5
1
0.0005

• The sample is the 10% (w/v) ash solution filtered by Grade No. 5C filter paper ifter it had been constantly shaken for six hours.
 Table 4.7   Analysis of Exhaust Gas

Particulate
Matter
Sulfur Oxides
Ammonia
Hydrogen
Sulfide
Trimethylamine
Methyl-
mercaptane
Methylsulfide
Mercury
Cadmium
Lead
Arsenic
Cyanide
Copper
Zinc
Nickel
Chromic Acid
Hydrogen
Chloride
Chlorine
g/Nm3
Nm3/hr
"
"
"
"
ppm
mg/m3
"
"
"
"
"
"
"
"
ppm
"
Inlet of
Scrubber
1.00
3.94
0.004>
0.155
0.0023

0.12
0.45
0.28
2.89
0.013
13.4
1.1
12.22
1.1
0.47
9.4
7.9
Outlet of
Scrubber
0.20
1.74
0.004>
0.137
0.0015

0.24
0.27
0.13
2.70
0.01 >
29.0
0.28
3.42
0.29
0.21
17.2
8.0
Standards
(less than)
0.7
6.54
134
2.685
0.671



0.3
0.5

40
0.3

3
0.3
20
3
Remarks
Air Poll, Prev. Law
Pub. Nuis. Prev. Reg.
of Kyoto Pref.
Offensive Odor
Prevention Law
Standards set by
Public Nuisance
Prevention Regulations
of Kyoto Pref. to be
applied Incinerators of
Wastes, such as Waste Oil
and Rubber.
                                           43 -

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in Table 4.6.  When the ash is used for landfill, a caution must be  taken  against
pollution of ground water by them. If the concentrations of a toxic substances in
the solution,  which  is  made  with the  ash  in accordance  with the regulation,
exceed the standards,  the sludge is adjudged  toxic  and has to  be disposed of by
the method specially stipulated.
     For the  confirmation  of freedom from  toxicity,  the solution  of ash  is
regularly tested. The results of recent ten tests are summarized in Table 4.6.
     Only  a  few  toxic substances  have  been found  by the  tests,  but  the
concentrations are much less than the  stipulated standards.
     Thus  there is no  problem of toxic substances. However,  calcium and some
others are  found  in  the ash solution  as shown in Table 4.8 and the pH of the
solution  is alkaline.  Figure 4.6 shows the  relationship  between the pH in the
solution  and  the  dilution  ratio of the  stipulated  solution  diluted with  ground
water.
                    Table 4.8  Composition c f Ash Solution
pH
Total Solids
Total Hardness
Calcium Hardness
Magnesium Hardness
Chlorine Ion
Alkalinity
Silica
mg/1
-
„
,,
„
..
"
10.64
2,098
1,154
841
313
253.0
92.3
27.5
            10.0
             9.0
             8.0
             7.0
Figure 4.6  Changes of pH of Ash
           Solution by Dilution
                                     Note: Dilution Water:
                                           Ground Water pH6.86
                              5             10
                             —S» Dilution Ratio (times)
                         15
                                   -  44 -

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4.5  RESEARCHES ON SLUDGE ASH FOR ITS REUSE
     It  is expected that  the quantity of sludge ash will rapidly increase from now
on.  However, it  is very hard to  obtain the space for filling up. Therefore, it  is
necessary  to  develop  a  new  method  to effectively  reutilize the  ash.  Now
researches  are under way  on such matters as  how to revivify the ash in  nature,
how to  use  the  ash  as  a  material for road construction,  how to use the ash to
make a lightweight aggregate, and  others.

4.5.1  UTILIZATION FOR SOIL CONDITIONERS
     Table 4.9 shows  an example of the  fertilizer  components  in  the ash. The
slaked  lime  that  is  added as a coagulant  at the dewatering process remains as
residue in  the ash. Therefore, it can  be used as a neutralizer of acid soil. Further
it can be used as a  fertilizer because of the components shown  in the Table 4.9.
Experimentally the  ash  is effective for the growth of root-crops. The growth of
aquatiic rice is also  satisfactory if it is given appropriately. However,  more careful
researches  are required  on the  effect of the '.eavy  metals  contained  in the ash
before it is widely used as  fertilizer.

4.5.2  USE AS A MATERIAL FOR ROAD CONSTRUCTION
     Experiments  prove the  possibility  of using the  ash  as  the  material  of
subgrade and subbase  course  of  the road. In October 1973 when a road was
constructed in the Toba Plant, the ash was tentatively used as the material of the
subgrade. As for the quality the result seems satisfactory,  though it  is still being
carefully observed. To fill an excavated area in the Plant the ash was also used.
     As  shown by Table 4.10,  the particles of the ash are  very fine. Therefore,
when "it is used  as  a  construction material, a caution must be  exercised  not  to
scatter it.
Table 4.9
                  Fertilizer Com-
                  ponents of Ash
Table 4.10
Grain Size Dis-
tribution of Ash
Components
N
P20S
K20
Fe203
Si02
CaO
MgO
MnO
B202

0.10
4.00
0.35
11.39
29.91
34.22
2.55
0.14
0.05
Grain Size (mm)
4.76' 2
2 0.42
0.42 0.074
0.074 0.005
Less Than 0.005

2
18
27
48
5
                                     45  -

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CHAPTER 5.   SLUDGE PRODUCTION AND SOLID LOADING BALANCE
              IN  THE  NISHIYAMA STP, NAGOYA
Outline of the Nishiyama STP	47
Equipment and Devices Installed  .  .   .     .      	    	47
Primary Sludge Production      	   48
Sludge Production through the Actuated Sludge Process .  .     	49
Increase in  Sludge Production by Chemical Addition  ....       . .        ... 49
Summary and Future Tasks   	       	    .      .     49
                                 46  -

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5.   SLUDGE PRODUCTION AND SOLID LOADING BALANCE IN THE NISHI-
     YAMA STP, NAGOYA

     Methods for ultimate  disposal and sites for  disposal  of sludge are limited in
Japan. Therefore, to obtain correct information on sludge production and its quality
in sewage treatment plants is of vital importance to setting up future measures for
treatment and disposal of sludge.
     As people's life style, especially their dietary life, changes year by year, sludge
production is increasing in sewage treatment plants. Also, the quality of sludge is
expected to change: for example, its organic content will increase.
     The  purpose  of  the project  is to obtain information on  sludge production,
quality  changes, kinetics of sludge production,  etc.  by  means of a  long-range
measurement at a typical treatment plant of domestic sewage which introduces the
activated  sludge process.  The  Nishiyama STP  in  Nagoya has  been selected and
surveys have been carried  out  jointly  by the N:>goya City and the  Public Works
Research Institute, Ministry of Construction. All data collected during two years of
surveys will be finally analyzed by a statistic measure.
     Discussed in the following are equipment and devices installed in the Nishiyama
STP for these surveys and results of the  survey of its beginning stage.

Outline of the Nishiyama STP
     In the Nishiyama STP, sewage is  collected by separate sewers, and biological
treatment by the conventional activated sludge process is conducted after the prima-
ry treatment. Population served is 46,000  and  the average flow is 20,000 m3 /day
(5 mgd).
     Raw sewage quality is as follows (daily average of the  period from February to
June,  1975): BODs, 70 ~  125 mg// (average 100 mg//)  and SS, 60 ~ 230  mg//
(average  130mg//). Diurnal variation is large and  thus STP is a typical treatment
plant for  domestic sewage. Average loadings per capita base computed from average
influent polutant loadings, 46 g/person/day for BODs, 60 g/person/day for SS, 10.9
g/person/day for TN, and 1.52 g/person/day for T-P, all of which are average values
in Japan.
     Fig.  5.1 shows the  flow diagram of the STP. Its bays are separated into two,
to one of whose aeration tank alum is added now.
     Sludge treatment is  not carried  out in the  STP   Produced sludge is stored in
holding tanks, then pumped to  nearby sludge treatment plants periodically.  Because
supernatant is not  returned from  sludge loading facilities, the STP is convenient to
obtain exact loading balance.

Equipment and devices installed
     In this STP, withdrawal of sludge from the primary  setter has been intermit-
tently performed 4 to 5 times/day and  that of waste activated sludge, 1 to  2 times/
day, depending on  its production.
     Since it is difficult to measure manually all of the sludge, three electromagnetic
flow meters  for measuring  sludge  flow  rate and  three ultrasonic solidmeters for
                                     47

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measuring solid in the sludge have been installed. Fig.  5.1 shows their respective
locations. Of the three, one  is for measuring sludge withdrawn from the primary
setter while the other two are for measuring waste activated sludge. Values measured
are transmitted  to  the  control room  and continuously recorded there.  Fig. 5.2
shows installed meters.  During four months  until  July, 1975, major troubles have
not occurred in connection with these meters.
     Observations from the solidmeters remain stable for waste activated sludge con-
centration  and the  differences with observed values  are within  10%. This may be
because in  the case  of waste activated sludge, fluctuations of concentration is small,
its quality is stable, and its withdrawal is conducted in a comparatively longer period
(about 30 minutes)  with a pump. On the cont -ary, since sludge in the primary setter
is withdrawn in a shorter period (about 5  m  mtes) by gravity and its concentration
changes greatly, it was difficult to get accural; results.
     To  know the potentials  for sludge production, it is necessary to continuously
measure  the water quality of influent and  effluent  of each facility. To measure the
concentration of suspended solids  and organic matters continuously, turbidimeters
and TOC meters are scheduled to be install.
     Because corelation  between turbidity and SS has  been found, measured turbidi-
ty is converted into  SS values. As turbidimeters, the surface scatter type, and as TOC
meters,  the type which continuous sample dose is possible, will be introduced. Fig.
5.1 shows locations of turbidimeters and TOC meters. As for TOC, it is planned to
measure  samples from each location after dividing them into "total" and "soluble."

Primary sludge production
     Table 5.1  shows the analytical values of the  primary  sludge. The percentage
of organic  matters in sludge amounts to as high as 85%. The ratio of TKN and  T-P in
the total solids was 1.7 to 3.7% and 0.3 to 0.7%, respectively.
     Primary sludge production is the balance between solid amount in influent and
that in effluent. Until turbidimeters were installed, SS had been analyzed using com-
posite samples for 24 hours. Fig.  5.3 shows  the relations between observed  values
of solid  quantity of influent and effluent and primary sludge withdrawn obtained
from values shown by flowmeters and solidmeters. Data are those from April to mid-
June. Figures in the upper column are the observed values of withdrawn amount and
those in the lower column are quantity of influent and effluent solids, the balance of
these two being estimated values of withdrawn amount.
     As shown in the Figure, values measured by meters and those obtained from
the balances between influent and effluent quantity are not very well correspondent
with each other.
     Reasons for this disagreement are not very  clear but causes which can be con-
sidered are: (1) the composite sample used was not representative; (2) mistakes or
errors in calibrations of  meters; and (3) analysis  method of SS cannot represent the
total quantity of the primary sludge.
     Table  5.2 shows the operational condition of the primary setter,  and  Table
5.3 shows average water quality.
                                   - 48  -

-------
Sludge production through the activated sludge process
     It has been pointed out that production of waste activated sludge is influenced
by a lot of factors. At this moment only a few  data have been obtained, so discus-
sions on kinetics of production is not done here.
     Fig. 5.4 shows reletions between waste activated sludge produced in the con-
ventional activated sludge process  and  solids  in influent and effluent. The former
was  obtained  from flowmeters and solidmeters while the latter was gained from
composite samples for 24 hours, both manually. When MLSS in the aeration tank is
constant, the net sludge production is obtained by substructing influent solids from
the total of waste activated sludge and effluent solid.
     During this period,  average  daily influent  BODs  loading  was 680 kg/day,
average daily  effluent BOD5 loading,  105 kg/day,  and removed BODs  loading,
575 kg/day. Other operational conditions are shown in Table 5.2 and 5.3.
     Tranfer rates into sludge per day computed based on soluble BODs vary wide-
ly. After TOC meters  are installed,  studies on transfer rates based on TOC, in addi-
tion  to BODs, and the production kinetics will be conducted using measurement
data covering a long period.

Increase in sludge production by chemical addition
     Production of waste  activated sludge at  the  bay where alum is dosed at the
extreme end of the aeration tank has been measured.
     Alum is dosed so that Al/P may become  2 in the mole ratio. Ah (SO4 )s Hz O is
the ingredient of alum and the concentration of dose is 8 mg Al/P
     Because the bay  where alum is dosed and that where it is not dosed  have the
same influent quantity, production  of them have been  compared on the basis of data
from May to June, 1975. The results are shown in Table 5.4.
     The quantity of  sludge at  the bay with alum has increased more than that at
the bay without alum.  The increase  rate was nearly 40% for the former.
     In the Table, the  estimated values of the increase in terms of aluminum hydrox-
ide and aluminum phosphate are shown. From these values, it  is known that the
quantity of alum dosage equals the increase in production  of waste activated sludge.
     Comparison between them  are planned to  be examined by changing  the dose
rates of alum.

Summary and future tasks
     The outline of the project at  the Nishiyama  STP to make a survey on sludge
production  from sewage  treatment  plants started  in  February, 1975  has  been
described in the above. Because this project is still at its initial stage, sufficient infor-
mation has  not  been  obtained yet. It is expected, however, that the results to be
gained from this project will give data useful to  sludge treatment and disposal plans
at sewage treatment plants to be built in the future.
     Future  tasks of the survey of the project will be as follows:
1)   By observation of sludge production for  a  long period  of time, to clarify sea-
     sonal fluctuations of its quantity and quality, yearly changes, etc.
                                  - 49 -

-------
2)   To install turbidimeters and TOC meter and to clarify effects of concentration
     of suspended solids in sewage on sludge quantity and the kinetics of transfer
     into sludge in the process of biological process of organic matters.
3)   To clarify material loading balance in sewage treatment plants.
4)   To study a long-range view for methods of sludge treatment and disposal at
     sewage treatment plants, mainly on the treatment of domestic sewage.
                                   -  50

-------
Table 5.1   Primary Sludge Characteristics
^\^ Item
Sample ^\^
1
2
3
V.S content
(%)
83.4
85.7
84.7
TKN content
TS base (%)
1.2
3.1
1.4
VS base (%)
1.5
3.7
1.7
T-P content
TS base (%)
0.3
0.7
0.7
VS base (%)
0.4
0.8
0.4
                -  51

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                                                                   Table 5.2   Operational Conditions of the Plant
on
Average
daily flow
(m3/d)
21,300
Primary settler
Detention
time
Or)
1.8
Overflow
rate

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Table 5.3  Waste Water Characteristics
                                                            (mg/£)
^\Category
Item ^\^
Turbidity
S.S
BOD5
TOC
T-P
TKN
Raw sewage
Ave.
80
118
99
80
3.54
25.2
Range
56 -132
81 -162
69 -124
51 -122
2.59- 4.92
21.8 - 29.1
Primary eff.
Ave.
52
41
64
59
3.45
25.8
Range
32 -92
31 -78
47 -95
38 -87
2.01- 4.40
20.6 -39.1
Final eff.
Ave.
6.7
6
9.5
19.3
1.25
13.1
Range
4.1 -11.3
2 -11
6.5 -16.5
8.3 -14.5
0.59- 1.97
9.9 -21.0

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                       Table 5.4   Comparison of Sludge Production
Sludges
Waste activated suldge
kg/d
(rng/2)**
Solid in effluent
kg/d
(mg/£)**
Total
kg/d
(mg/2)**
Addition as A1(OH)3 *
kg/d
(mg/C)**
Addition as A1P04 *
kg/d
(mg/C)**
Control

536
(45.4)

77
( 6.5)

613
(45.4)

-
-

-
-
Alum addition

545
(46.1)

310
(26.2)

856
(72.5)

184
(15.6)

139
(11.8)
* Calculated value.        ** Based on inflow.
                                        - 54

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            ITM)
            ,X

Grit
Chamber

viuu
1
1
1 _


Preaeration
Tank



 SM )  Solid Meter
 FMI   Flow Meter
.TOCI  TOC Meter
(TM)   Turbidity Meter
V -S
                                                                                                    	»-  To the Adjacent STP
            Sewage
 	—   Sludge
                                            Fig. 5.1   Flow Diagram of Nishiyama STP

-------
   ILLUSTRATION NOT AVAILABLE
Fig. 5.2  Installed Flow Meter and Solid Meter
        (Waste Activated Sludge Pipe)
                      56

-------
Cn
--0
                                                                          Solid Withdrawn
                                              D
                                                                                                      Influent Solid
                                                                                                                             I••:•:I  Effluent Solid
                                 10
15


April
                                                                   20
                                                                                    25     20
                                                                                                             25
                                                                                                                              30     1
                                                                      Calendar Date                         May

                                                                  Fig. 5.3   Solid Loading Balance Over Primary Settler
                                                                                                   June
                                                                                                                                                                     10

-------
c_n

oo
                               700 -J
                               600 H
                               500 A
J

a 400



1
o
_J
                               300 J
                               200 -J
                               100 -\
                                                               Influent Solid





                                                               Effluent Solid





                                                               Waste Activated Sludge
                                           20   21    22   23    24    25   26    27    28    29    30    31     1     2     3    4     5     6     7



                                                                       May                       Calendar Date                         June



                                                               Fig. 5.4   Solid  Loading Balance Over Activated Sludge  Process
                                                                                                                                                          9     10

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                           Fourth US/JAPAN Conference
                                   on
                           Sewage Treatment Technology
                                Paper No. 2
AUTOMATION AND INSTRUMENTATION FOR
    WASTEWATER TREATMENT  PLANT
               October 24, 1975
                Cincinnati, Ohio
            Ministry of Construction
              Japanese Government
                    - 59

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             AUTOMATION AND  INSTRUMENTATION FOR
                  WASTEWATER TREATMENT PLANT
1.  Basic Conception of Automation and Instrumentation in Sewage
   Treatment Plant  ....            	61
     A. Sugiki, Japan Sewage Works Agency

2.  Automatic Water Quality Measurement for Wastewater Treatment	  '2
     K. Murakami, PWRI, Ministry of Construction
                                -  60

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       CHAPTER 1  BASIC CONCEPTION OF AUTOMATION AND
                   INSTRUMENTATION IN SEWAGE TREATMENT
                   PLANTS


1.1   Introduction     	           	62

1.2   Some Points to be Solved in Automatic Control  	   62

1.3   Basic Conception for Automatic Control	      	63

1.4   Profile of Automatic Control Systems	64
                                                                 /- rj
1.5   Future Research	        ....
                               - 61

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1.1   INTRODUCTION
     Several different characteristics exist in the waste water treatment process as
compared to such process at an ordinary manufacturing process. These particularities
are  necessary to be taken into consideration when the instrumentation and the auto-
mation are introduced into a sewage treatment plant. For instance:
(a)   Both quantity  and quality of sewage flow vary to a great extent regardless of
     the  optimum conditions of a  sewage  treatment processes. Accordingly,  it is of
     necessity to  forecast and preestimate it to some extent for operation as opti-
     mum.
(b)   Since a sewage  treatment plant concerns itself widely in the public interests and
     the  effluent  therefrom  has a great impact to the environment, it is needed al-
     ways to secure stable and best water quality of effluent. Minimum required con-
     ditions, of course, should be maintained even in an emergency.
(c)   Time required for through whole treatment process after arriving at a treatment
     plant ranges  from a few hours to 10 hours. In other words, the time constant is
     considerable long.
     Therefore, in order to increase the treatment efficiency the feed  forward con-
     trol is requisite.
(d)   Although mechanical and physical treatment process such as screening and sedi-
     mentation are  included in  the waste water treatment process, biological treat-
     ment plays a main role for waste water treatment in Japan.  Hence a control
     system should  be built  up  for the most suitable environment to microorganism.

     As  the sewage treatment plant becomes  larger, process has rather long time
constant and combination of complicated  many different systems, so it is very dif-
ficult to  operate it properly. To cope with this complexity it has been necessitated
to introduce  the technique of electronic instrumentation as to systematic control on
the process.
     Types of instrumentation and control devices range from a analog controller to
a large-scale digital computer, and  all are being in  wide use according to the purpose
of control and the scale of treatment plants. As to introducing a computer although
there are arguments the general trend goes to the introduction of computer. The case
of waterworks which  is rather ahead in the instrumentation and the automation of
water purification plants gives a  good example.  At the present, the use of computer
is limited to a role of an information center: such as data collection, indication, re-
cording,  supervision, data storage  and calculation. However,  with the further pro-
gress of  studies on  the mode of biological  treatment process and development of
software, various types of  feed forward  control, adaptive control or optimizing
control will be made available, and  the function of computer control may be far be
improved.

1.2   SOME POINTS TO BE SOLVED IN AUTOMATIC  CONTROL
     If the technique  of automatic control is  introduced into the operation and
maintenance  of a sewage treatment plant, it will become possible  to control more
effectively for treatment process under the characteristics of the sewage treatment

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mentioned above,  and at  the same time the reduction of personnel expenses and
further more than  cutback of treatment cost and  also the improvement of working
conditions of the staff to  be engaged in as well as the labor and skill saving are ex-
pected.  However,  the  relation  between  the effects  or  benefits of the automatic
control and the costs required for it, that is to say, the cost performance, would be
variable according  to the scale of treatment plants and/or the respective local condi-
tions such as fluctuation of water quantity and quality. There are some technical and
operational problems left to the future to need technological development as follows.
(a)   Highly dependable various automatic measuring devices and  instruments are
     required for the automatic control. Many of the quantitative measuring instru-
     ment such as a flow measuring devices and  a  water  level meter are available
     now, except some modification in needed some cases. On the contrary, the
     insufficient performance of reliability, responsibility, stability and repeatability
     etc. particularly of detectors (sensors) of the qualitative measuring instrument
     such as a suspended solid or an organic substance,  BOD, COD, TOC etc., has
     been pointed out.
(b)   Operation and maintenance of treatment plant usually depend on the experi-
     ence and intuition of skilled employees. When the automatic control is put into
     practice, it becomes necessary to select suitable operational indices for this kind
     control. We need kinetic model of treatment process, and now strongly con-
     ducted studies but unfortunatedly not yet the models are determined. Further
     development  of measuring apparatus  as well as  kinetic models of treatment
     process would be expected.
(c)   With the implementation of the automatic control, manner of operation  and
     maintenance are conducted in  different ways. Therefore, it is highly necessary
     to  establish a system of education and  training for the staffs in charge so that
     they may fully  understand the system composition and how it works and may
     perform a proper operation and they may  take necessary action promptly and
     correctly to cope with abnormal condition in  emergency.

1.3  BASIC CONCEPTION FOR AUTOMATIC CONTROL
     The basic conception for the water treatment system was formulated as follows
after having been taken into consideration the previously-mentioned characteristics
of the process at this time.
(a)   Since the studies of process kinetics and the development of respective water
     quality sensors and still incomplete at the moment, it is appropriate to lay more
     emphasis on  the  quantitative control. These points, however, seem  to be de-
     veloped step  by step with time. After evaluation on new developments, new
     techniques are introduced for the qualitative control time to time.
(b)   Although sewage  treatment plants are mostly planned to complete with in next
     20 years, a stage  construction  method is usually  applied. Therefore,  the auto-
     matic control should be so designed as to function  at every stage respectively.
     For the treatment plant, of which  designed capacity exceeds 100,000 cubic
     meter employed,  a computer should be introduced.
                                   - 63

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(c)   The quantitative control plays a main part presently, but as treatment plant
     become larger in scale, items of supervision and data to be handled increases so
     much that the operation under man power may exceed his ability.  Hence, a
     computer should be introduced to ensure the more effective and more detailed
     automatic supervision on various apparatus in plant to keep operation record
     and process control. In this case, back up  system should be prepared in order
     to secure to keep good operation in case of emergency.
(d)   Pumping stations for sanitary sewage and storm sewage need to be so designed
     that they will be operated automatically according to the scale, rather small and
     at the same time, it is necessary to ensure the remote supervision and control
     from a treatment plant or the nearest pumping station.
(e)   In future, it is required to measure rainfall precipitation, water level, amount of
     flow and water quality, etc.  at the desired points in the catchment area and to
     transmit to a central  control office through telemeter devices so as to enable
     more reliable rational operation to control stormwater.
(f)   Even though a treatment plant is planned with quantitative automatic control,
     the  necessary incidental facilities are needed at  the planning stage so that  the
     qualitative automatic control will be possible in future.

1.4  PROFILE OF AUTOMATIC CONTROL SYSTEMS
     Sewage treatment process consists of pumping station, preliminary  sedimenta-
tion tank and chlorination tank all working as one system.
     Explanation will be made below as to the forms and methods of control, while
referring to those machinery, instruments and devices that are included in the con-
trolled system by each establishment. It is briefly described on the control system in
each process.
(a)   Pumping station
     Pumping stations are  cassified into  booster pumping station and those in  the
     treatment plants, and also collecting sewage system differ  from the separate
     system to the combined one. Fundamentally for all the types control systems
     of pumping station are about same one with little alternation by the case. Ap-
     paratus such as inlet gate, screening, grit chamber, sanitary sewage pump and
     storm  sewage pump are to be controlled in a pumping station. Inlet  gates  are
     manipulated so as to  control incoming sewage to treatment plants. Operation
     of the  gate are controlled by sign  of the unusual rise of water level at an inlet
     or at a wet wall. Usually, when water level goes over the height already set  up,
     the  gate will be closed automatically with  a use of analog regulators, etc., and
     the  manipulation to open it is performed at on site or through the remote
     manual operation if possible, which needs such as reservoir pond. Of course,
     in case the incoming  flow rate is desired  to be  controlled for the better per-
     formance of treatment, it should be designed  to make possible the closing gate
     through the remote manual operation. The control in this case will be needed
     such devices that the  sequence control device coupled with the measuring ap-
     paratus are to be required.  In future, if incoming How rate of sewage  can  be
                                    -  64  -

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forecast with a use of rainfall precipitation data in a catchment area and so on,
or the forecast of the quality of incoming water will be made available with a
use of monitoring apparatus of water qualities, the feed forwared control and
adaptive  control  become applicable  with the additional introduce of the pro-
cesser control apparatus.
If there  are installed grit chamber,  the adaptive control  and the optimizing
control should be applied thereto with the  surface loading or the velocity of
flow in the chamber being constant rate. In the control with a constant rate of
surface loading, an inlet gate is manipulated after selecting the number of cham-
ber according  to  the incoming flow rate of water. The control with a constant
velocity of flow in the chamber is performed by manipulation  an inlet gate and
an outlet gate  after  selecting the number of basin according  to the incoming
flow rate and the water depth of the chamber. In this case, the sequence control
device, the measuring apparatus and the process control apparatus are necessary
and  the  control is conducted by sequential  computer control method. As for
grit chamber, the programmed and the conditional control are both used joint-
ly, and in the  former the time scheduled operation is performed with  a use of
incoming flow pattern,  while in the  latter it works only when a difference in
water  level  before and behind a screen exceed a fixed difference. A screen
scraper and  lifting machine  and a belt conveyer are naturally in combinated,
and  the  control appratus are the sequence  control device and the measuring
appratus. Further, a  control based on the forecast of the volume of screenings
produced will be  installed in future. Since  it seems possible to presume  the
volume of screenings produced  on the total  volume of incoming flow, the pro-
cesser  control appratus is necessary to be set up so that equipment of screen,
i.e. rake  scrapers may  start working when  the  total volume reaches a fixed
amount.
In respect of grit removal facility,  the control method is also  the same as that
of a screening devices. The programmed control, under which the time sched-
uled operation is performed with a use of incoming flow pattern, is applied to
start working machine at the condition which the facility  starts working when
the volume of grit deposit reaches a fixed height.
Automatically-operated  sanitary sewage and storm  sewage pumps  are to be
under  the level control (conditional control), and  thereby they start working
when the water level  at wet well (in the case of a storm sewage  pump, the water
level reaches a fixed level which pump should be started) reaches the upper
limit of a fixed point and stop when reaching the lower limit.
In the case of a sanitary sewage pump the level control depending on the water
level at a wet well for rather unusual  condition, flow control are needed so that
inflow and outflow are regulated to  maintain as  to the certain flow velocity in
grit chamber as possible. The outflow rate will be controlled through the selec-
tion of the  number  of  pump, the number of revolution  and the opening of
control valve,  and the sequence control device and the measuring apparatus for
are required for this purpose. If the optimum control of outflow rate is  planned
in future, the processer control apparatos will become essential.
                              -  65 -

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     A storm sewage pump is controlled depending on the condition based on the
     water level at wet well or at the point where effluent discharge. In future, if the
     time comes when the inflow  pattern, the detention time of sanitary sewer, etc.
     can be  forecast through the  rainfall, or when the necessary data for estimate
     incoming flow  rate of sewage can be transmitted  from a booster pumping sta-
     tion and/or the desired points along a force main just like in the case of a storm
     sewage pumping station in the treatment plant, the feed forward  control will be
     made available  by adding the processer control apparatus.
(b)   Primary sedimentation tank
     Such appratarus  as  sludge pump, a withdrawal  valve  and a scum  collecting
     device are  to be  controlled by instrumentation.  A sludge pump and a with-
     drawal  valve start working by  signal of timer and stop when  sludge density
     lowers down to desired concentration  or when the sludge volume withdrawal
     reaches are  fixed volume.  In future, it is necessary to combine the level control
     under which they start working when  the measured volume of  sludge deposit
     reaches the  upper limit  of  a certain height and stop when sludge height reaches
     the lower limit.
     A scum collecting device is switched on  and off intermittently at on site or
     through the remote manual-operation,  aside from being controlled by signal of
     timer.  In future, the feed  forward control is to  be introduced depending on
     pattern of  scum volume produced which is forecast by incoming flow  rate,
     water quality.  Accordingly, the processor control apparatus will be needed in
     future in addition to the sequence control device and the measuring apparatus.
(c)   Aeration tank
     Appratus that are the controlled system of an aeration tank include a blower, a
     suction valve for  air supply, and a return sludge pump. A blower and a suction
     valve are to supply an adequate volume of air for the microbic  reaction in an
     aeration tank.  There are two  kinds of control systems on dissolved oxygen in
     aeration tank. One is the proportional  control of incoming flow rate of sewage
     and the other is to keep constant dissolved oxygen concentration in the tank.
     The former is  the control in supplying the  air in proportion to the incoming
     flow rate of sewage, whereas  the latter is to control the air by signal from a dis-
     solved oxygen meter so as to maintain the dissolved oxygen concentration in an
     aeration tank at a fixed  concentration. The air supplied is adjusted by the num-
     ber of blower and the opening of suction valve. In future, the optimum control
     is to be employed which are  depending on the estimation  of the required vol-
     ume of air from the incoming flow rate and water qualities (BOD, COD, TOC
     etc.) as well as of signal from a dissolved oxygen meter in aeration tank. In the
     case of a return sludge pump, the  number of pump and the number of revolu-
     tion are controllable, based on the required volume of return sludge. As for the
     switchover of the number of pump, a starting order would be arranged so as to
     the same running period of respective  pumps. Its control method include the
     proportional control of the incoming flow rate and the MLSS at the  constant
     concentration based on the density of return sludge. In this cases, it is necessary
                                   -  66

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     to  equip the sludge  holding  tank for preperly return sludge.  In future,  the
     optimizing control should be performed in consideration of the  biological acti-
     vate of return sludge as well as the BOD load (f/M) after  measuring the BOD
     (COD, TOC) in the raw sewage.
(d)   Final sedimentation tank
     In  the final sedimentation tank a excess sludge withdrawal pump which starts
     working under signal  of a timer and stops when the sludge density lowers down
     to  a fixed concentration, or when the top of sludge zone reaches down to a
     fixed height. The timer is being set itself upon the programmed control utilizing
     a pattern of incoming  sewage. In future, the level control will be put to  use
     under which a excess sludge withdrawal pump  starts working when the height
     of  sludge deposit reaches the upper limit of a fixed height and  stops upon its
     down  to the lower limit. Further, it is to focus the optimizing control of sludge
     distribution of tanks  by estimation of sludge produced from the quality of raw
     sewage for example the BOD or COD, TOC.
(e)   Chlorination facility
     There is some difficult situation whether chlorination of sewage effluent is ef-
     fective means or not  especially regards to downstream water supply system. At
     present time, chlorination is required to sewage effluent if coliform counts in
     the effluent exceeds  3000/ml. Next  action not yet determined in relation to
     chlorination, but some alternation will be expected.
     Chlorination is applied in proportion to the flow rate of effluent, but its con-
     centration  of  chlorination  in  effluent would  be  determined  measuring  the
     concentration of residual chlorine and the counts of coliforms.
     In  future, as the optimum control of chlorination would be such manner as
     injected after measuring automatically the residual chlorine, then the processer
     control apparatus is to be required in addition  to the sequence  control device
     and the measuring and operational apparatus.
     A  detoxitation devices are required for emergency emission of chlorine gas in
     chlorination chamber. An aspiration blower of the escaping gas  and an injeca-
     tion pump of the dechlorination agent such as sodium thiosulfate start working
     by signal from detector for chlorine gas. The manipulation to stop of dechlori-
     nation devices should be done at the machine side for the sake of safety.

1.5  FUTURE RESEARCH
     The problems on the  development of automatic  control of treatment plant
operation were pointed out, and the best practical system  at present was proposed.
     Also  target system in future is shown, but joint efforts of government people
and manufacturers is inevitable for the application.
     Study report about automatic control development has been presented since
1960 in Japan and even simulation model study by computer is published now.
     Since  1974 development study by a manufacturer granted  from Ministry of
Construction and same study by Japan Sewage Works Agency started  from investiga-
tion of many types of sensor and process kinetics Analysis.
     The abstract of our study objects  is as follows.
                                     67  -

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(a)   We are going to do systematic investigation of durability, operational difficulty
     and accuracy of measuring equipment and make the questions clear.
(b)   We are going to design and construct treatment plant which adops best applica-
     ble full automatic controll system proposed by us. Then the cost-effectiveness
     performance will be cleared.
(c)   We are continueing the kinetics study of actual plant operation.  And using
     30 m3/day pilot plant which will be complete by 1976, simulation experiment
     is going to be done under various operation conditions to aim quality control
     application in future.
                                     68  -

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Items To Be Measured Manually at a Final Sedimentation Basin
(1)   Cadmium and its chemical compound;
(2)   Cyanide;
(3)   Organic phosphate compound;
(4)   Lead and its chemical compound;
(5)   Sexivalent chrome compound;
(6)   Arsenic and its chemical compound;
(7)   Mercury, alkyl mercury and other mercuric compound;
(8)   BOD (Biochemical Oxygen Demand);
(9)   COD (Chemical Oxygen Demand);
(10)   SS (Suspended Solid);
(11)   Transparency.
                                   69 -

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A DRAFT OF AUTOMATIC CONTROL AT SEWAGE TREATMENT PLANTS

                            AT THE PRESENT HME
\Vaier
Treatment
Facilities
Pumping
Station
Preliminary
Sedimentation
Tank
Aeration
Tank
Final
Sedimentation
Tank
Chlonnalion
Facility
Control Device
Controlled System
Inlet Gate
Screenings Facility
Sand Removing
Facility
Sanitary Sewage
and Storm
Sewage Pumps
Raw Sludge Pump
Pulling-out Valve
Scum Removing
Device
Blower
Return Sludge
Pump
Surplus Sludge
Pump
Chlortnation
Device
Neutralization
Device
Control Form
Open Loop
Control
- ditto -
- ditto -
Closed Loop
Control.
Open Loop
Control
Open Loop
Control
- ditto -
Open Loop
Control,
Closed Loop
Control
Open Loop
Control,
Closed Loop
Control
Open Loop
Control
Closed Loop
Control
Open Loop
Control
Control Method
Conditional Control
(Remote Hand-
operation)
Conditional Control
Programed Control
- ditto -
Level Control
Discharge Control
Conditional Control
Feed Forward
Control
Conditional Control
Programed Control
Conditional Control
Conditional Control
DO Uniform Control
Proportional Control
of Inflowing Volume
of Water
Conditional Control
MLSS Uniform
Control
Proportional Control
of Inflowing Volume
of Water
Conditional Control
Programed Control
Processer Control
Uniform Control
Conditional Control
Constituent Apparatus
Sequence Control
Device
Processer Control
Apparatus
Measuring Control
Apparatus
Sequence Control
Device
Measuring Control
Device
Sequence Control
Device
Sequence Control
Device
Measuring Control
Apparatus
Processer Control
Apparatus
Sequence Control
Device
Measuring Control
Apparatus
- ditto -
- ditto -
- ditto -
Sequence Control
Device
Measuring Control
Apparatus
Processer Control
Apparatus
Sequence Control
Device
Measuring Control
Apparatus
Processei Control
Apparatus
- ditto -
Back-up
Use What is
One Rank
Below the
Control Method
- ditto -
- ditto -
- ditto -
- ditto -
- ditto -
- ditto -
- ditto -
- ditto -
- ditto -
- ditto -
Items to be
Supervised
(Automatically)
Water Level at
Pump Well
Water Level at
Inflowing
conduit
Water Level
Before and
Behind Screen
(Volume of Sand
Deposit)
Water Level at
Pump Well
Inflow Rate PH
Volume of Raw
Sludge Pulled out
Density of Raw
Sludge (Volume
of Sludge
Deposit)
Volume of
Wind Sent
MLDO (MLSS)
Return Sludge
Rate
Density of
Return Sludge
Volume of
excess Sludge
Density of
excess Sludge
(Volume of
Sludge Deposit)
Volume of
Water
Discharged
Chlorine dosing
rate
Concentration of
Escaping
Chlorine
Hems for
Manual
Measurement

Volume of
Screenings
Volume of
Sand Removed



SV
Residual
chlorine
Concentration
(as per
attached sheet)
MPN

Items for
Data Process
Rainfall
Precipitation.
Water Level,
inflow rate PH
(Volume of
screenings.
Volume of
Sand Removed)
Volume of
Sand Deposit
Volume of Raw
Sludge withdrawn
Density of Raw
Sludge
Volume of
Sludge Deposit
MLDO, MLSS
(SV)
Volume of
Return Sludge
Density of
Return Sludge
Volume of
excess Sludge
Density of
excess Sludge
Volume of
excess Deposit
Volume of
Water Discharged
Chlorine
dosing rate
residual Chlorine,
MPN
Concentration of
Escaping Chlorine
Remarks
Data Processing Device:
Small-scale (Punching Recorder and
Integrating Meter)
Medium- and Large-scale
(Daily Report, Monthly
Report, Trouble and
Running Record using
an electronic computer)
Central Monitory Facility:
Monitoring, Operate
ITV (Sand Basin, Discharging
Outlet and other facilities
inside a plant to be
monitored)
Note: A storage tank for return
sludge is required.
                                                Items in the parenthesis
                                                are to be measured,
                                                but not to be used
                                                for the control
parenthesis
is to be fLUed
manually

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IN  THE  FUTURE
Water
Facilities
Pumping
Station
and Storm
Sewage Pumps
Preliminary
Sedimentation
Tank
Aeration
Tank
Final
Tank
Chlorination
Facility
Control Device
Controlled System
Inlet Gate
Screenings Facility
Sand Removing
Facility
Sanitary Sewage
and Storm
Sewage Pumps
Raw Sludge
Pump Outlet
Valve
Scum Removing
Device
Blower
Return Sludge
Purnp
Excess Sludge
Pump
Chlorination
Device
Neutralization
Device
Control Form
Open Loop
Control
- ditto -
- ditto -
Open Loop
Control,
Closed Loop
Control
Open Loop
Control
- ditto -
Open Loop
Control,
Closed Loop
Control
- ditto -
Open Loop
Control
Closed Loop
Control
Open Loop
Control
Control Method
Conditional Control
Remote Hand-
operation
Conditional Control
Programed Control
- ditlo -
Conditional Control,
Level Control
Inflowing Volume of
Water Control
Feed Forward
Control
Conditional Control
Programed Control
Conditional Control
Conditional Control
Ratio Control of
Ail Volume
Cascade Control
Optimizing Control
Conditional Control,
Optimizing Control,
Programed Control
Cascade Control
Uniform and Ratio
Control of Return
Sludge Volume
Conditional Control
Programed Control
Processes Control
Uniform Control of
Injected Volume
Ratio Control of
Injected Volume
Conditional
Control
Constituent Apparatus
Sequence Control
Device
Measuring Control
Apparatus
Processes Control
Apparatus
- ditto -
- ditlo -
- ditto -
- ditto -
- ditto -
-ditto -
- ditto -
- ditto -
-ditto -
Sequence Control
Device
Measuring Control
Apparatus
Back-up
Use What Is One
Rank Below The
Control Method
- ditto -
- ditto -
- ditto -
- ditto -
- ditto -
- ditto -
- ditto -
- ditto -
- ditto -
- ditto -
Items to be
Monitored
(Automatically)
Water Level at
Pump Well
Water Level at
inflowing
conduit
Water Level
Before and
Behind Screen
Volume of
Sand Deposit
Water Level at
Pump Well
Inflow rate
PH
Volume of Raw
Sludge Pulled
Volume of
Sludge Deposit
Density of
Sludge

airflow rate
MLDO
MLSS, SV
Volume of
Return Sludge
Density of
Return Sludge
TOC(orTOD)
Volume of
excess Sludge
Density of
excess Sludge
Volume of
Sludge Deposit
Rate of Water
Discharged
Chlorine dosing
rate
Residual Chlorine
Concentration
of Escaping
Chlorine
Items for
Manual
Measurement

Volume of
screenings
Volume of
Sand Removed





(as per
attached sheet)
MPN

Items for
Data Process
Rainfall
Precipitation,
Water Level,
inflow rate
PH
Volume of
Sand Deposit
(Volume of
screenings,
Volume of
Sand Removed)
Volume of
Raw Sladge
Pulled out
Volume of
Sludge Deposit
Density of
Sludge
air flow rate
MLDO, MLSS,
SV
Volume of
Return Sludge
Density of
Return Sludge
TOC (or TOD)
Volume of
excess Sludge
Density of
excess Sludge
Volume of -
Sludge Deposit
Volume of
Water Discharged
Chlorine dosing
rate
Residual Chlorine
of Escaping
Chlorine
Remarks
Data processing device is for daily
report, monthly report, trouble and
running record through jn electronic
computer.
Central Monitory Facility:
Monitoring, Operate
ITV (Sand Basin, Discharging
Outlet and other facilities
inside a plant to be
monitored)
Note- a storage tank of return sludge
is required.
                                                                       Items in the
                                                                       parenthesis is to be
                                                                       filled manually

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CHAPTER 2.   AUTOMATIC WATER  QUALITY  MEASUREMENT FOR
              WASTEWATER  TREATMENT
2.1  Introduction   	     .      	73
2.2  Automatic Water Quality Monitoring of Raw Sewage	    	73
  2.2.1   Development of Automatic Cyanide Monitor	73
  2.2.2   Automatic Measurement of TOC	    	75
  2.2.3   Automatic Detection of Surface Oil	' *>
2.3  Automatic Measurement of Water Quality for Process Control of the
    Secondary Treatment	       .  .  .  . 75
2.4  Automatic Measurement of Water Quality for Process Control of the
    Tertiary Treatment    	          	    .      76
  2.4.1   Measurement of Nutrients such as Ammonia Nitrogen by Automated
         Colorimetric Analysis      	      ....   76
  2.4.2   Automatic Measurement of Ammonia and Nitrate by Electrodes  ...   76
  2.4.3   Use of Turbidimeters	     	          77
  2.4.4   Others	       	77
2.5  Future Aspect of Study      	      .        78
                                   72  -

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2.    AUTOMATIC  WATER  QUALITY  MEASUREMENT FOR  WASTEWATER
     TREATMENT
2.1  INTRODUCTION
     In the field of wastewater treatment, measurement of water quality is necessary
for a variety of purposes, such as water quality monitoring of industrial wastes
discharged into the  sewerage system, water quality monitoring of influent to sewage
treatment  plants,   process  control  of  the  secondary and  tertiary  (advanced)
treatment, and  water quality monitoring of effluent from sewage treatment plants.
Virtually all of these measurements are now performed by manual sampling and
analysis.  In  many  cases, however, automatic continuous measurement is  needed.
Water quality  parameters for which continuous measurement can be now used are
very limited except  in the case of  comparatively clean treated water. Water
temperature, pH,  oxydation-reduction potential,  dissolved  oxygen  and  sludge
density,  are parameters which  can be measured without much trouble. Even in
measuring these parameters, considerable maintenance and inspection are required.
     Major points that need a special consideration in the development of automatic
continuous measurement of sewage quality are as follows:
(a)  Growth of slime
     Because sewage normally contains a lot of organic matters and is suitable for
propagation of microorganisms, biological slime tends to grow inside the piping or
other portions  of the equipment contacting sample water. Slime  not  only causes
clogging but interferes measurement.
(b)  Effects of suspended solids
     When measuring  water quality of raw sewage containing high suspended solids,
consideration much be given to minimize clogging at sampling portion or inside the
piping. The use of automated colorimetric analysis is  difficult  when  the  level  of
suspended solids is  high.
(c)  Existence of interferences
     Generally  speaking, the composition of sewage  is more complex than those of
river water or industrial wastewater and therefore masking  of interferences  is more
critical.
     Thus automatic  continuous measurement of  sewage  water  quality is  more
difficult  than that  of river water,  etc.  But  as its necessity is very  high, efforts are
made to develop and put into use devices for this purpose.

2.2  AUTOMATIC  WATER QUALITY MONITORING OF RAW SEWAGE
2.2.1   DEVELOPMENT OF AUTOMATIC CYANIDE MONITOR
     Cyanide is one of the toxic substances  which may be discharged into  the
sewerage system. By controlling its discharge, reduction of discharge of heavy metals
from industries such as plating works  can be attained. Therefore, the Ministry of
Construction gives  the  first priority   to the development of automatic  cyanide
monitoring device.
     The Ministry has been supporting studies on developing automatic free  cyanide
monitoring device  including field  tests using  model devices during the past two
                                   - 73

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years. In measuring cyanide by selective-ion electrodes, it is the most important to
prevent the  effects of interferences.  Sulphide,  iodide, bromide,  sulphite, thio-
sulphite,  thiocyanate  and  organic substances  with SH-radical  are the  major
interferences which  may  be present in  sewage.  However, in the case of normal
sewage, only  sulphide  will bequire consideration. Fig. 2.1  shows the degree of
interferences of anions other than sulphides. Sulphides were removed first from
samples by  addition of cadmium nitrate. And then, each sample was devided into
two parts. One part of the sample was  then anion exchanged. The same amounts of
cyanide were added to both parts of the sample, and the concentrations of cyanide
were measured by  an ion electrode. The  figure  shows that measurement of raw
sewage is  possible  when masking of sulphide is performed. In the  case of primary
effluent of night soil treatment plants,  interferences of anions other than sulphides
are perceived. Most of these are considered to be organic substances with SH-radical,
such as thioglycollic acid. For the masking of sulphides, cadmium, bismuth, zinc and
lead are effective. Above all, the most stable masking is possible by adding cadmium,
so cadmium mitrate has been used in  field tests.  But because adding these heavy
metals to  sewage even in a small quantity is not desirable, other methods of masking
are being  studied,  such as  one using filter paper on which  cadmium is coated by
vacuum evapolation or one utilizing other masking agants than these heavy metals.
In the  former method, cadmium can be recovered easily but the amount of sulphur
to be  removed is limited and is not suitable for sewage containing a large quantity of
sulphides. As masking agents other than heavy metals, it has been found that sodium
nitroprusside and several types of nonionic and anionic polymers (if added in a high
concentration) are effective,  but  they are also toxic.  Thus,  studies  must  be
continued to  find  more proper masking methods of sulphides.  For masking of
organic substances with SH-radical, it  has been proved that  sodium molybdate is
effective.
    Fig. 2.2 shows the block diagram of model device. In the early stage of field
tests at the  Kisshoin Sewage Treatment Plant, Kyoto, several points to be improved
were discovered. Most essential of them was the phenomenon that the surface of the
sensing element of the  cyanide electrode was  deteriarated even  if masking of
sulphides  had been carried put. To cope with this, the electrode was modified as
shown in Fig. 2.3 so that mechanical scraping can be performed continuously.
    After the above modification, test runs have been continued over one year until
today during which maintenance work  such as calibration has been done every two
weeks. Table 2.1 shows causes by which data could not be obtained during  1974 and
the ratios  of the  periods during  which data were  lost to the total period of
operation. The period during which data  could not be obtained is about 37% of the
total period. This is  not  very  small percentage  but  most  of the  causes  can be
eliminated by more frequent inspection  and maintenance work  and it is not very
difficult to reduce the percentage to less than 10%.
    Though there remain some problems with masking agents, we  could develop a
usuable equipment  for automatic free cyanide measurement.  However, as pretreat-
ment   standards provide  for  regulations  for total cyanides including  complex
cyanides in most cases, there is a need for measuring total cyanides, not only for free
                                   - 74

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cyanide. Several devices for automatic measurement of total cyanides are already on
the market, but they have not virtually been applied to the measurement of cyanides
in sewage. It is considered that a lot of troubles will be encountered in these devices
for actual measurement. Therefore, a project is now being carried out to remodel
them through field tests.
2.2.2   AUTOMATIC  MEASUREMENT OF TOC
    The Area River Basin (Left Basin) Sewerage Authority is conducting automatic
measurement of TOC  to determine organic loadings to their sewege treatment plant.
Similar measurement is carried out in Osaka Prefecture for water quality monitoring
of storm water overflow from combined sewer. Models used  are different  but both
models  suffer from clogging at  sampling portions and piping. The  former model
which sample  water is continuously injected by a peristaltic pump, was faced with
such problems as  fluctuations in  measurements caused by non-uniform entrance of
SS, fluctuations in the base line, precipitation of minerals on the  inlet port of the
furnace,  and,  during  earlier  stages, corrosion  of  the  piping  material  due to
hydrochloric  acid.  On  the  other hand, in the case of Osaka Prefecture where
intermittent measurement method  is used, though the sample line is cleaned by
water while measurement is not carried out,  cloggings of the injection valve occurred
frequently.  In any  case,  troubles  by  SS are unavoidable in  the  automatic
measurement of TOC of raw sewage. At this moment there are no alternatives but to
reduce these troubles by frequent maintenance and inspection.
2.2.3   AUTOMATIC  DETECTION OF SURFACE OIL
    Development of  automatic  devices for surface oil detection for use in sewers
and pumping stations is now being continued by studies financially supported the
Ministry of Construction. Methods under study are measuring fluorescence emitted
by the radiation of ultraviolet rays, measuring reflecting light by the radiation of
infrared rays of two wave lengths, and measuring changes of mutual  inductance.

2.3 AUTOMATIC MEASUREMENT  OF  WATER  QUALITY   FOR  PROCESS
    CONTROL OF THE  SECONDARY TREATMENT
    Parameters requiring automatic measurement to conduct process control of the
secondary treatment include dissolved oxygen,  concentration of organic  matters
expressed  by TOC, etc., MLSS,  sludge density, etc. Of these parameters, measure-
ment  of  concentration of  organic  matters  expressed  by TOC,  etc.  has many
difficulties. But other  items are basically in the stage of practice today, though there
remain problems including necessity for frequent maintenance and inspection, and
insufficient accuracy of measurement.
    There is no sewage treatment plant in Japan in which air to aeration tanks is
controlled automatically in accordance with the concentration of dissolved oxygen
in tanks. However, studies for them are being performed widely including full scale
experiments. It has been affirmed that automatic measurement of dissolved oxygen
in aeration tanks  is possible if calibration of electrodes and cleaning of electrode
surfaces are sufficiently done.
    For measurement  of sludge  density,  the  method using  ultrasonic  waves  is
extensively used.  It is said that  since the  development of devices for eliminating
                                      75

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interferences of air bubbles, measurement accuracies have been improved.

2.4  AUTOMATIC  MEASUREMENT OF  WATER  QUALITY  FOR  PROCESS
     CONTROL OF THE  TERTIARY TREATMENT
2.4.1   MEASUREMENT  OF  NUTRIENTS SUCH AS  AMMONIA  NITROGEN
       BY AUTOMATED COLORIMETRIC ANALYSIS
     Water quality measurement of secondary or tertiary effluents can be conducted
by means of automated  colorimetric analysis, because SS is low and slime growth is
less.
     In the tertiary treatment pilot plant established in the Toba Sewage Treatment
Plant in Kyoto, continuous colorimatric analysis of ammonia nitrogen is carried out,
for automatic control of the break-point chlorination process. Major points to which
special attention  was  paid in  the development of this device  are as follows: (1)
output is linear within the range between 0 and 20mg/l of ammonia nitrogen; (2)
dual  filtering  devices are installed  so  that they  can  be  cleaned  alternative; (3)
disinfection device is installed to prevent growth of slime; (4) color of sample water
is compensated; and (5) automatic calibration is performed at least once a day.
     The method used is the salycylate-dichloroisocyanurate reaction with ammonia
(1). This method  has an  advantage that the color development is stable even in high
concentration  of  ammonia nitrogen,  as compared with the Nesslerization Method
and  the  Phenate  Method.  The block diagram  of  this device is  shown  in Fig. 2.4.
Samples  are heated to approximately 85°C for  a short  period to prevent slime and
algae growth. But when  measuring treated water from the break-point chlorination
process, disinfection by  heating is not performed, because measured values become
smaller when  samples are  heated and  of  slime control  is unnecessary. To filter
sample water, ceramic filters with a mean pore size of 30/u are used. Backwash by air
and water is conducted automatically. Comparison of analytical values by this device
with those by  the manual  Nesslerization Method is  shown in Fig. 2.5. According to
the Figure, when the  concentration of ammonia  nitrogen becomes about 20mg/l,
analytical values  by  automatic measurement  tend to  be  smaller.  This is because
calibration is  performed  at  Omg/1  and   10mg/l, though  absorbance becomes
somewhat non-linear when concentration exceeds about 15mg/l. But as a whole the
results are satisfactory and automatic control of the treatment process is conducted
satisfactorily by means of feed forward control using this device.
     For  automatic  control   of coagulant dose  in  chemical  clarification  for
phosphorus removal, an  automatic measurement device of hydrolyzable phosphorus
based on similar  principle is now being developed. For this device disinfection  by
ultraviolet  rays to prevent slime growth is  also considered. Concerning filtration,
synthetic resin filters are  examined, not only ceramic ones.
2.4.2  AUTOMATIC  MEASUREMENT  OF   AMMONIA  AND  NITRATE  BY
       ELECTRODES
     In  measuring ammonia and nitrate, use of ion electrodes is one  of the best
methods.  Therefore,  in the   above-mentioned pilot  plant  for  the  break-point
chlorination  process,  surveys  on  application of  these  measuring  devices  are
conducted. Since  nitrate ion electrodes are interfered by chlorides and others, they
                                     76

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are difficult  to  be used for measuring nitrate  in  the  effluent from  break-point
chlorination process. Therefore, they are now used only for measuring nitrate in the
influent.
     Measurement of ammonia is carried out for both influent and effluent. In the
latter,  because there exists a possibility that the membrane is damaged by residual
chlorine and chloramines,  measurement  is  done  after passing  samples through
activated  carbon  columns.  The results  of  experiments so far shows that the
reliability of  the measurement by ammonia electrode is  somewhat lower compared
with that by colorimetric analysis.  Another disadvantage is the short life of the
electrode. It lasts only a few months when  used continuously.
     Experiments  of measurement of nitrate in the secondary treatment water by
means  of nitrate electrodes have just begun. The results obtained so far are not so
encouraging.  One of the reasons for this is insufficient maintenance and inspection,
so experiments are being continued with more frequent maintenance and inspection.
If continuous measurement of nitrate in the secondary effluent becomes possible by
means  of ion electrodes,  it will be utilized for automatic control of biological
denitrification process.
2.4.3   USE OF TURBIDIMETERS
     The Sewage Works Bureau of Tokyo Metropolitan Government is conducting
surveys at  its pilot  plant  for granular media filtration of the  secondary effluent
which   is  built  in the Morigasaki  Sewage  Treatment  Plant,  in  order  to  use
turbidimeters for automatic control of granular media filtration. In this pilot plant
various types of  turbidimeters are  installed. At  present,  a  falling  stream  type
turbidimeter  (scattering light of 23°) is being used for measurement of influent and
effluent turbidity, while  for measuring  turbidity  of  backwash  waste  water the
surface scattering  type  one is introduced. At though there  are some  problems of
slime growth in dealing with less treated water, there are virtually no trouble in
measurement. There are corelations between turbidity and SS as shown in Fig. 2.6
depending on the type of the water measured.
     In the pilot plant  for the tertiary treatment in the Toba Sewerage Treatment
Plant in Kyoto, the surface scattering type  turbidimeters are now used for measuring
turbidity of  influent to filters, effluent  from filters and effluent from chemical
clarifier. Also, studies are being conducted concerning control of fitter backwash by
using turbidity of backwash waste water.
2.4.4  OTHERS
     In the pilot  plant for filtration in the Morigasaki Sewage Treatment Plant,
Tokyo, in  addition  to  the abovementioned measurement of turbidity,  automatic
measurement of TOC, TOD, dissolved oxygen and  residual  chlorine is performed.
Measurement of residual chlorine is  conducted when  chlorine is  dosed to control
slime growth.
     TOC and TOD are  of types in which sample water is continuously injected by a
peristaltic pump. They  need remodeling including increase in diameter of pipes at
inlet port to the furnace, increase in gas cooling capacity, and providing of activated
carbon column to adsorb hydrochloric gas.

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     In  measuring dissolved oxygen, after flow  cells have been introduced which
allow higher contact flow velocity, the maintenance of about once a year has been
sufficient.

2.5  FUTURE ASPECT OF STUDY
     Automatic measurement  of water quality for process control of the tertiary
treatment gives few problems in the development of devices  for it, because it deals
with comparatively clean water. Thus a various kinds of devices have already been
developed and more will be devised in the future when necessary. On the  other
hand, automatic measurement  of  water quality of  row  sewage and industrial
wastewater  discharged into the sewerage system has seldom been conducted in spite
of its high necessity, and there are almost no devices available for  it. Monitoring of
heavy metals and other toxic materials is one of the most important factors for the
operation and  maintenance of a sewage treatment plant. Therefore, studies in this
field should be positively promoted  in the future. Such studies should include, in
addition to those on measuring methods  themselves, improvement in methods of
sampling and filtration, methods of slime control, and methods for dissolving heavy
metals contained in solids.

REFERENCE
1)   Searcy, R.L., Reardon, I.E. and J.A.  Foreman, "A New Photmetric Method for
Serum Urea Nitrogen Determination", American  Jour, of Medical Technology, Vol.
33, No. 1, 1967.
                                 - 78

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Table 2.1   Inventory of Data Loss During 6 Months Operation of
           Automatic Cyanide Monitor
Causes of data loss
Malfunctions of recorder chart drive
Running out of chart paper
Running out of recorder ink (pH)
Running out of recorder ink
(CN-pH)
Power failure (main source)
Fuse blow
Breakage of pH electrode
Clogging of strainer
Malfunction of vacuum pump
Running out of NaOH solution
Shortage of inner solution of refer-
ence electrode
Total
Total period of operation
Period of data loss
(hrs)
92
156
176
429
96
151
138
38
42
80
196
1,594
4,320 (hrs)
Percentage of data loss
(%)
2.1
3.6
4.1
9.9
2.2
3.5
3.2
0.9
1.0
1.9
4.5
36.9

                          79 -

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                                                     Primary Effluent of Night Soil
                                                     Treatment Plant
           5         10''       2            512            5

        Reading of Electrode in Sulphide Free and Anion Exchanged Water, CN (mg/C)


Fig.  2.1   Interferences of Anions Other Than Sulphides with Cyanide

           Measurement by Ion-Selective Electrode
                               -   80

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       Drain
Vacuum
Pump
Air Com-
pressor
                 Sampling Tank

                     Iwater Level Switch
                             i	i
                            Strainer
                                                                pH Con-
                                                                trol for
                                                                Cyanida
                                                                Measurement
                                                         n
                                                         PH
                                               0
                                                PH
                                                                     J
To Sample 	
Preserva-   	s|_
tion            ""
                                                           To Waste
                                                                            To Waste
                      Fig. 2.2  Block Diagram of Automatic Free Cyanide and pH Monitor

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Sensing Element

Scraped Face	

Stainless Steel Blade
             Fig. 2.3  Cyanide Electrode with Continuous
                      Scraping Device
                       -  82  -

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                        Drain
             Backwash
             Water
             Air for
             Backwashing
CO
Changeover Valve                    Changeover Valve

                    Sampling Cell

                                    25 cc/H
                                                           Standard    Pure Water
                                                           Solution
Mixing Coi

1
-AAAAAA ,

\
Flow-cell of
Colorimeter for
Reference ,. i 	
(D\. •— '^ • 1>
y^-^ ^H
4.2cc/H
ID 1
Heating Coil
for Color Develop-
ment (40°C)


Flow-cell of
Colorimeter
for Measure-
ment
                                                                                                                                                                      • To Waste
                                                                                   Alkaline Dichloro-
                                                                                   isocyanurate
                                                                                   Solution
                    Sample Water
                                         To Waste
                                                           Fig. 2.4   Block Diagram of Automated Ammonia Analyzer

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   20  r
00
    15
>,
a
<   10
0)
o
o
P
o
O Influent (Effluent from Filter or
   Activated Carbon Contactor)

^ Ettluent from Break-point Chlorina-
   tion Process
                      5              10              15

                   Manual Nesslerization Method, NH4-N (mg/2)
                  20
         Fig. 2.5  Comparison of Ammonia Nitrogen Concentrations obtained by
                  Manual and Automated Analyses
                                         84  -

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oo
en
              20
                     4 -
                   S3
                   "So
              10
                                                                                      5            6           7

                                                                                           Effluent Turbidity
                                                                                                                                      O [nfluent to Filter

                                                                                                                                      O Effluent from Filter

                                                                                                                                      D Efluent from Filter - While Chlorine is Dosed
                                               10
                                                                        20
                                                                                     25          30           35


                                                                                            Influent Turbidity
                                                                                                                           40
                                                                                                                                        45
                                                                                                                                                     10
                                                                                                                                                     50
11
55
             12
            _l
             60
                                   Fig. 2.6   Relationship between Turbidity Measured  by Falling-Stream Type  Turbidimeter and Suspend Solids

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                               Fourth US/JAPAN Conference
                                        on
                               Sewage Treatment Technology
                                      Paper No. 4
RECENT  PROGRESS IN  ENVIRONMENT  QUALITY
                     IN  JAPAN
                   October 29, 1975
                   Washington, D. C.
               Ministry of Construction
                 Japanese Government

                         86 -

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                       CONTENTS

i    NATIONWIDE SURVEY ON MERCURY AND PCB POLLUTION	89
 1.1  Findings About Meroury Pollution	.....89
  1.1.1  Fish and Shellfish	89
  1.1.2  Quality of Water	90
  1.1.3  Bottom Sediments	91
  1.1.4  Soil and Farm Products 	91
  1.1.5  Controls at Sources of Pollution	92
 1.2  Findings about PCB Pollution	93
  1.2.1  Fish and Shellfish	93
  1.2.2  Quality of Water	94
  1.2. 3  Bottom Sediments	94
  1.2.4  Soil and Farm Products 	95
  1.2.5  Controls at Sources of Pollution	95
 1.3  Overall Evaluation	96
II   CASE STUDIES ON MERCUBY AND PCB POLLUTION	97
 2.1  Case Studies on Meroury Pollution	97
  2.1.1  The Case in Tokuyama Bay	97
  2.1.2  The Case in Jinzu River	103
 2.2  Case Studies on PCB Pollution	  103
  2.2.1  The Case in Lake Biva 	
  2.2.2  The Case in Tsuruga Bay 	
Ill  REVISIONS OF ENVIRONMENTAL AND EFFLUENT STANDARDS ON
     MERCURY AND SETTINGS OF  ENVIRONMENTAL AND  EFFLUENT
     STANDARDS ON PCB	  105
 3.1  Meroury	  105
  3.1.1  Reasons for Amendment	  105
  3.1.2  Main Points of Revision	  107
 3.2  PCB 	108
  3.2.1  Basic Principles 	109
  3.2.2  Consideration of Relevant Factors 	  109
  3.2.3  Environmental Quality Limit on PCBs	110
  3.2.4  Waste Water Discharge Standards „..	  Ill
                              - 87 -

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  3.2.5  Provisional Standard for Removal of PCB-
         Contaminated Sediments	112
IV    PROVISIONAL STANDARDS FOR REMOVAL OP CONTAMINATED
      SEDIMENTS 	 112
 4. 1  Mercury-contaminated Sediments	112
  4.1.1  For Sea Area	112
  4.1.2  For Rivers and Lakes	113
 4. 2  PCB-oontaminated Sediments	113
                               88 -

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I   NATIONWIDE SURVEY ON MERCURY AND PCB POLLUTION

    A nationwide survey in Japan on mercury and PCBs (polychro-
linated biphenyls) pollution  was done during  the period  from
July '73 to March «74.
    Undertaken at a time when contamination  of fish, shellfish
and the environment by mercury and PCBs is becoming  worse, the
survey was aimed at obtaining factual data on the actual  state
of affairs and investigating the causes of pollution.
    The ultimate objectives were, of course, to assure the saf-
ety of fish and shellfish and establish the basic countermeas-
ures required to clear the environment of mercury and PCBs.
    Participating in the survey were  the  Environment  Agency,
the Ministry of International Trade and Industry, the  Ministry
of Transport, and the Ministry of Construction.     Prefectural
governments across the country cooperated in the survey.    The
gist of the findings and an overall evaluation are given below:

1.1  FINDINGS ABOUT MERCURY POLLUTION
1.1.1  Fish and Shellfish
    Tested for mercury were 22,403 samples of 303  species,  of
fish and 6l6 samples of plankton which were collected from  124
inland bodies of water and 144 sea zones.
    The majority of the species covered were cleared for  fish-
ing and marketing, as their mercury levels were found to be be-
low the provisional standards.     But some fish species caught
in Minamata Bay and Tokuyama Bay, where voluntary fishing rest-
rictions are already in force, exceeded the provisional limits.
So did some species caught in the sea off Naoetsu  in   Niigata
Prefecture — such as "ishimochi (Argyrosomus argentatus)","ka-
nagashira (Lepidotrigla microptera)", "magarei (Limanda   yoko-
hamae)" and "akamutsu (Upeneus bensasi)" — and  some   species
caught in the inner parts of Kagoshima Bay — such as "tachiuo",
                               89 -

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"madai", "akana",  "anago" and  "raaaji".  Voluntary fishing curbs
have been put into effect on these species following the  earli-
er discovery of high mercury presence by Niigata and Kagoshima
prefectural governments.
    Fish and shellfish in the  sea off  Naoetsu and inner   parts
of Kagoshima Bay must be kept  under continued surveilance.  The
fact that investigations of bottom sediments failed   to   reveal
the causes of pollution in these areas calls for a more intens-
ive probe into the mechanism of contamination, so  that   neces-
sary countermeasures can be formulated.
    Fish caught in nine rivers showed mercury levels well  above
the provisional standards.  The earlier surveys of these  rivers
had resulted in similar findings except for one   in   Nagasaki
Prefecture, and the inhabitants living along the rivers    have
already been given dietary guidance by the authorities.
    The contamination of these rivers may be spontaneous   since
many of them flow through regions where there has  historically
been some pollution originating from mercury mines.     A  close
inquiry, nevertheless, is required to determine the     precise
cause of river pollution and the effectiveness   of    possible
countermeasures by implementing such steps as reducing the dis-
charge of pollutants at known sources, removing  bottom    sedi-
ments that are dredged where necessary, plus conducting regular
checks on fish and shellfish in the interim.
    Surveilance of foodstuffs is also being maintained in  fish
markets to assure the safety of fish and shellfish   that   are
channeled to consumers.
1.1.2  Quality of Water
    The water aspect of the mercury survey involved 3,768  samp-
les taken from 331 rivers, 156 ports and harbours,  and 147  sea
areas.   Seventy-six samples, or two percent of the total, were
found to contain total mercury levels exceeding  0.005 ppm.
    The samples topping the environmental  quality    standards
                               90

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were from the Mukagawa River in Hokkaido, the upper  reaches of
of the Tone River near Shibukawa in Gumma Prefecture, the Shin-
gashi River in Tokyo, the Torigai River in Osaka (a   tributary
of the Kanzaki River), Minamata Bay, and a canal linked    with
Toyama Port.   The causes of pollution in these areas  need  to
be clarified so that the necessary counterraeasures  can be  in-
stituted.
1.1.3  Bottom Sediments
    A total of 5»l86 samples of bottom sediments were  examined
for mercury.   They were collected from almost the  same  areas
where the water-test samples were taken — 332 rivers,155 ports
and harbours, and 148 sea zones.   Samples from 16  rivers  and
nine ports and harbours — i.e., 120 samples, or 2.3 percent of
the total — registered mercury values in excess  of  the  pro-
visional standards for removal of polluted sediments.
    Dredging work has already been completed or is in  progress
in most of these bodies of water.   Sections that need dredging
should be designated promptly in other areas   after   detailed
investigations.
1.1.4  Soil and Farm Products
    Samples of soil were tested for mercury at 707 spots —ord-
inary tests at 469 places and close examinations at  58  places
in the vicinity of factories handling mercury.
    Values recorded in ordinary tests, in terms of  total  mer-
cury, ranged from ND (not detectable) to a maximum of 5*36 ppm,
the great majority of them being below 1.5 ppm.   It seems safe
to conclude from this that densities of total mercury contained
in common specimen of soil is less than 1.5 ppm.
    The samples were analysed for organic mercury.        But no
appreciablelevels of methyl mercury and ethyl   mercury    were
detected.
    The test produced readings ranging from a low  of  0.07 ppm
                             - 91

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to a high of 67 ppm, with the great majority of the samples be-
ing below 1.5 ppm.    Practically no methyl mercury  nor  ethyl
mercury was detected.
    Tests on farm products were conducted at 702 spots —ordin-
ary tests at 464 places and scrutiny at 238 places.
    Samples of unhulled rice involved in ordinary tests  showed
values ranging from ND to a high of 0.17 ppm.        The  great
majority of the recorded readings were below 0.01 ppm.   Methyl
mercury and ethyl mercury were practically nonexistent.
    Total mercury readings resulting  from  close  examinations
ranged from ND to 0.12 ppm, the great majority of them    below
0.01 ppm — not necessarily high compared with the results   of
ordinary tests.    Practically no methyl or ethyl  mercury  was
in evidence.
1.1.5  Controls at Sources of Pollution
    Appropriate treatment or disposal of waste water and refuse
is imperative to deter further environmental disruptions.
    The situation has remarkably improved with regard to  waste
water — with strict controls being enforced across the country
— instead of in limited bodies of water as before, under   the
discharge standards established in May,  1971> on the basis   of
the Water Pollution Control Law.
    The discharge standards were strengthened further in August
1974.    Especially noteworthy is a fact that the main  sources
of mercury pollution — factories that turn out caustic soda by
using mercury and vinyl monomer and acetoaldehyde by using ace-
tylene — have been shut down or have carried radical changes—
either in production processes or by installing self-containing
waste-water facilities.
    Factories that were built after the  establishing of custody
and disposal standards on industrial refuse in September, 1971,
in line with the Waste Disposal and Public Cleaning Law are be-
ing given guidance so that their refuse  is properly disposed of
                               92

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 in  accordance  with these  rules.
    As for  factories  that existed before  the    standards   were
 fixed, the  assumption is  that  as  a general  rule,  their   refuse
 is  being  safely  gotten rid of  or  adequate counterraeasures   are
 in  effect.     There are cases  in  which refuse  is  buried  or  in
 custody in  the factory grounds, some  of it  outside  the grounds.
 There seems to be  no  problem,  judging from  the quality of water
 in  the neighbouring body  of water.     There are also   factories
 where concrete,  clay  and  other materials  are as covers to  keep
 pollutants  from  flowing or seeping away when it rains.      But
 available information is,  admittedly,  still insufficient     in
 some oases.

 1.2 FINDINGS  ABOUT PCS POLLUTION
 1.2.1  Fish and  Shellfish
    Checks  on  fish and shellfish  were  carried  out in  20  bodies
 of  water — all  of which  had shown questionably high  levels  of
 PCBs in the  previous  surveys — with  3,369  samples  being tested.
 The estuary of the Tama River  in  Tokyo and  the Nagara Hiver  in
 Aichi Prefecture,  in  addition  to  the nine areas where    self—
 restrictions on  fishing were instituted in  1973, were found  to
 be  more polluted than allowed  under the provisional  standards.
 Similar curbs  have been enforced  in the heavily    contaminated
 Taraa and Nagara  river sections following  earlier findings     by
 the responsible  prefectural governments.
    Factories  handling PCBs have  existed  along these  rivers  in
 the past, and  their pollution  is  fully accountable    from    the
 volumes of  PCBs  consumed  in the plants and  the extent  of   con-
 tamination  of  bottom  sediments.     What needs  to be done    now,
 therefore,  is  to make  sure  that stocks of PCBs are  recalled and
kept in the  hands  of  the  authorities until  they are disposed of.
Needless to  say, the  ban  on their use,  to be detailed later,  is
 imperative.
                                93

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    Of particular importance is the installation  of   sophist-
icated equipment for material screening  and  waste—water disp-
osal in used-paper recycling plants since water  discharged  by
these plants sometimes contain minute amounts of PCBs originat-
ing from pressure-sensitive copying paper and  other  types  of
secondhand paper.    Removal of contaminated bottom deposits in
accordance with relevant standards, to  be  fixed shortly,  and
other environmental cleaning measures are promptly for,with de-
tailed surveys made mandatory when necessary.
    Appropriate levels of surveilance  are  also maintained  at
fish markets to ensure the safety  of  fish and shellfish  sold
there.
1.2.2  Quality of Water
    Assayed for PCBs as affecting  the  quality  of water  were
l,28l samples from 208 rivers, 28 ports and harbours,and 46 sea
areas where fish and shellfish contamination had posed a  prob-
lem in previous surveys or where quality of water  examinations
had produced 1 ppm or more.   Fifty-five samples,  4«3  percent
of the total, logged levels higher than 0.0005 ppm.  These were
collected from 18 rivers and four sea zones.    Inquiries  into
the causes of pollution in these cases are in order,with neces-
sary countermeasures to be taken afterward.
    Compared with the previous year's findings, the   situation
improved on the whole, with reductions recorded both  in  terms
of the number of contaminated samples and PCB densities.
1.2.3  Bottom Sediments
    Bottom sediment tests were held on 1,789 samples  from  258
rivers, 33 ports and harbours, and 58 sea areas.   Samples from
14 bodies of water showed maximum PCB readings in excess of  50
ppm.     Maximum levels were between 10 and 50 ppm in  37  other
areas and between five and lOppm in another 21.
    Sediment removal work has been completed in some  of these
                               94 -

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regions.   As  for  the  remainder,  removal  or  other     counter-
measures  are called  for  on  the  basis  of the provisional removal
standards to established shortly,  with detailed  investigations
to be  carried  out  where  necessary.
    Exceedingly high levels of  PCB pollution were recorded   in
the previous year's  survey,  topping 10,000  ppm  in  some places,
but counter-measures  have been taken in the  areas  concerned.   As
a result,  the  latest survey did not such  extraordinary  peaks.
1.2.4  Soil and Farm Products
    PCB checks on  soil were conducted on  samples  from 105  pla-
ces in the vicinity  of factories  and  other  establishments  hand-
ling PCBs in five  prefectures and  two major cities with a  gre-
ater measure of self-autonomy accorded by law.    Recorded  dens-
ities  ranged from  ND to  59  ppm, the great majority of them be-
low 0.1 ppm.
    Farm  products  were found to be  practically  free of  PCBs.
1.2.5  Controls at Sources  of Pollution
    A  total ban has  been imposed on the use  of  PCBs in  manufac-
turing such goods  as copying paper, paint and ink.   The use of
PCBs in such products  as heat exchangers, heaters,  transformers
and condensors is  also prohibited  as  a general  rule.  Owners of
these  equipment already  in  use  are  urged  to  keep  them     under
strict control, and  in the  case of  products  in  which PCBs  serve
as a heat  medium,manufacturers  are  under  orders to replace them
with substitutes.
    Directives have  been issued to  institute proper  procedures
for the recall and custody  of copying paper  containing  PCBs and
make sure  that they  are  not  used for  reclaimed  paper    product-
ion.
    Components containing PCBs  are  being  removed  from discarded
home electrical appliances with the cooperation of  local   gov-
ernments.    The Appliance PCB Disposal Association has  been set
                                95

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up to collect such components and keep  them  in   custody until
they are disposed of, pending  the establishment   of    relevant
technology.   The association plans to extend its   services   to
the disposal of transformers, condensers and the like  disjoined
from heavy-duty equipment.
    While PCB contamination of waste water has improved on  the
whole from the previous year as a result of guidance   based   on
the provisional standards, controls  will  further strengthen-
ed under the full-fledged standards to be set shortly.

1.3  OVERALL EVALUATION
    As a result of the latest survey, without an   equal   scale-
wise in foreign countries, environmental realities  in  Japan   as
regards fish and shellfish, farm products,the quality  of  water,
and soil have been brought to light,  practically   wiping away
anxiety about unknown dangers of mercury and PCB pollution.
    With voluntary fishing restrictions   introduced   in   the
bodies of water which were found to be heavily polluted,  it  can
be said that a system to avert adverse effects on  the  health of
people through the intake of contaminated  fish  and   shellfish
has been set up.
    However, as is clear from the findings of the  survey,envir-
onmental health has yet to be restored in these areas, although
there has been improvement at the sources of pollution  in   the
overall picture.
    Our target is an environment which would  enable  people  to
eat fish and shellfish without any fear of health damage.    For
this purpose, the relationship between polluting factors     and
contaminated fish and shellfish must be cleared up.
    Polluting elements are traceable through periodical checks,
except for some bodies of water where  detailed  investigations
are needed.    For the time being, therefore,  emphasis   should
be placed on prompt implementation of measures to   improve   the
                               96

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 quality of water,  bottom sediments  and reduce  the   release   of
 pollutants at  their sources,  as it  was pointed out  before.
 Parallel with  the  effort,  necessary detailed     investigations
 should  be promoted,  with countermeasures  based on their  find-
 ings  to be worked  out  quickly.

 II    CASE  STUDIES ON MERCURY AND PCB POLLUTION

 2.1   CASE  STUDIES ON MERCURY POLLUTION
 2.1.1   The  Case in Tokuyama Bay
    Tokuyama Bay is  a  good natural harbour and  is  located  at
 the western part of  Honshu-island, and fronts  on  Seto  Inland
 Sea.    Tokuyama City (population 105,000) and  Shin-nanyo  City
 (population 34»000), both are industrial cities,  are  face  at
 this bay.
    Here,  Tokuyama Soda  Company (1952) and  Toyo  Soda  Company
 (1956)  had  been produced caustic soda  and chlorine  by  mercury
 caustic process.
    The total  amount of  mercury used and the  estimated  amount
 which had  been discharged into  the bay by these two   factories
 are shown  in Table 1 t
Table 1
Names of the Co.
  Names of the
    factories
  Date  of the
 investigation
Total amount of
mercury used(-t)
Mercury dis-
charged into
waste water (t)
Tokuyama Soda Co.
    Tokuyama

            1973
          703.2

          3.69
Toyo Soda Co.    Total
    Nanyo

 June 7, 1973
       558.6    1,261.8
       2.95
6.64
                                97

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    Since it was already known  that  the  fish and   shellfish  in
this bay were highly contaminated by mercury,  from  1.0   to 1.5
ppm, a close survey was undertaken on water,   bottom  sediment
and marine products, when the nationwide  survey   was  done  in
1973 as one of the water areas  that  seriously polluted by  mer-
cury.
    As to the result of water quality survey,all  the 69  samples
were "not detectable".
    On the contrary, allthe samples  of bottom  sediments   showed
mercury existence. (Table 2)

Table 2    The result of bottom sediments  of Tokuyama Bay
               Numbers of         Total  mercury
    ° 8        survey     Nrs of  Nrs      „  _  ...   _ „
points
A Sea area g
B 44
C
D
Sub-total
Toyo Soda
Tokuyama Soda
Tokuyama Soda
Sub-total
Total
121
40
416
2
2
1
5
421
samples deteo1
131 131
80 80
44 44
121
40
416
2
2
1
5
421
121
40
416
2
2
1
5
421
, I"lf tUl
d
6.64
4.56
3.85
2.63
0.91

5.15
13.32
0.56
7.50

1'ij.ii. — e
0.07 -
0.25 -
0.45 -
0.13 -
0.04 -

4.16 -
5.83 -

0.56 -

'IcUL.
31.57
18.98
7.25
19.50
2.96

6.14
20.8
0.56
20.8

    The Department of Technology of Yamaguchi University   est-
imates according to the results of these survey and  also   the
results of survey boring which were undertaken  at  the    same
time that the amount of mercury discharged from these two fact-
ories into this bay should be 13 - 14 tons (4 centimetre    be-
neath from the surface of the sea bottom) upto 36 tons (two me-
tre ditto).
    Many fish and shellfish were caught in this bay and analys-
                                98 -

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ed as to mercury.   Figure 2 shows the rslationship     between
concentration of mercury in fish and shellfish and  concentrat-
ion of mercury of bottom sediments.
Fig. 1   Map of Tokuyama Bay
                                      the Factories
                                99  -

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   Pig. 2   Relationship between concentration  of mercury  in  fish
            and shellfish and concentration of  mercury  of   bottom
       :     sediments
          c--"	—^   Black sea bream
   0.7
     x
    . o
1  0.5
a
ft
A
m
03
§
•H
•p
<&
0)
o
C
o
   0.1
Sea perch
Sea chub
Gizzard shad
Short-necked clam
Plankton
     Sea
                                                      Black  sea bream
                                                    Short-necked clam
                                                                o
Gizzard shad
      ___ . - O
                                                           Plankton
       Concentration of Hg in the bottom sediment(total Hg dry wt)
                                 100

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    Also a survey for mercury content in the hair of the  inhab—
itants(60 men and women) living along the coast of Tokuyama Bay.
Table 3 shows mercury content in women1a long hairs.

Table 3
Sample
No
No 2
(70 yrs
of age)
No 5
(57 yrs
of age)
No 15
(23 yrs
of age)
No 16
(52 yrs
of age)
Length of
hair( cm)
0-10
10 - 15
15 - 19
19 - 22
22 - 25
25 - 27.5
27.5- 30
Mean
0-10
10 - 15
15 - 20
20 - 25
25 - 29
29 - 33
33 - 37
37 - 41
41 - 44
44 - 47
47 - 50
Mean
0-4
4 - 6.5
6.5- 9
9 - 12.5
Mean
6 - 25 "
25 - 35
35 - 45
45 - 50
50 - 55
55-60
Mean
Conc.(ppm)
7.8
8.0
8.8
9.1
9.1
9.6
9.5
8.84
10.9
8.1
7.1
7.3
6.9
6.9
8.2
10.7
13.4 I
13.4
12.9
9.62
4.61
4.61
4.71
4.90
4.71
5.30
4.90
3.73
3.24
2,75
2.35
3.71
Sample
No
No 20
(25 yrs
of age)
No 29
(21 yrs
of age)
i
No 60
(42 yrs
of age)
i
No 61 ;
(42 yrs ;
of age)
Length of
hair (cm)
0-10
10 - 17
17 - 24
24 - 32
Mean
0-10
10 - 18
18-24
24-30
Mean
0 - 26
26 - 36
36 - 46
46 - 54
54 - 60
60-65
65 - 69
69 - 72.5
72.5- 76
Mean
0-10
10 - 15
15 - 19
19 - 23
23 - 28
28 - 33
Mean

Cone. (ppm)
2.35
2.94
3.82
3.94
3.26
7.36
8.04
6.67
7.36
7.36
3.14
3.14
2.65
2.94
2.55
2.75 i
3.24 i
3.53
3.82
3,08
2.8
2.8
2.2
2.4
2.6
2.4
2.53

Conclusion
1)   Dicharged quantities of mercury from soda-producing factor-
  ies should indicate the quantities of environmental pollution,
  but the facts are not so simple because of difficulty to   get
                               101

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  continuous records of effluent conoetration,and because of  the
  differences of water areal extent or levels of maintenance  of
  factories.
2)   There are little chances to detect mercury in water quality
  survey,and there is a problem as to the quantitative  analysis
  limit in the case of sea water.
3)   Mercury contended in bottom sediments could show the  quan-
  tities of mercury discharged or the state of the waste   water
  treatment of the factory concerned.
4)   When mercury concentration in surface potion of bottom   se-
  diments doesn't exceed 2 - 2.5 ppm (dry wt), the concentration
  of mercury in fish meat will not exceed 0.4 - 0,5 ppm (in   the
  case of sea water).
5)   Fish are good index for monitoring to pollution because  of
  their bioconcentration of methyl mercury.
6)   Generally speaking,  much—eating and bottom—inhabited   fish
  indicate greater magnification.   Crustacea and plankton don't
  indicate greater magnification.
7)   Hairs of inhabitants along the oast concerned, when analys-
  ed, tell the history in the past of mercury pollution for fish
  and water area concerned.
8)   It is scheduled that the bottom sediment of Tokuyama    Bay
  will begin to be removed within this year(concentration   over
  15 ppm).  It is anticipated that we could get the answer whet-
  her vastly spreading mercury in the bottom sediments    affect
  fish pollution or high concentration of mercury in     limited
  spots affect fish pollution.
9)   Middle-sized fish have 4-5 years of life, and also   biolo-
  gical half-period of methyl mercury is relatively long for 1 -
  2 years, we should consider that there are time-lags   between
  the concentration of mercury in fish and the     environmental
  clean-up performances.
                               102

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2.1.2  The Case  in Jinzu River
l)  Around in  the time  1967,  it was  disclosed  that  dace  in  Jinzu
River (flows through Toyama prefecture) were highly polluted   by
meroury( over  3  ppm), and mercury  in dace was  in  the form      of
methyl mercury.
2)  According  to the results  of surveys, the cause  of pollution
was suspected  to be the  pollution  caused by a     pharmaceutical
company situated along  the coast of  a branch river  of Jinzu Riv-
er.
3)  The production of "thimerosal  (an organic  mercuric disinfec-
tant, sodium ethyl-mercury thiosalioylate)" was rapidly  increas-
ed in 1968 to  1969.
4)  According  to the result of the survey held by the Institute
of Hygiene of  Toyama Prefecture it is disclosed that there  were
high concentration of meroury(2,300  ppm, including  32  ppm   of
methyl-mercury)in the bottom  sediments near the discharge point
of the factory.
5)  Halting the  production of "thimerosal,merthiolate" and  re-
moval of bottom  sediment which containing high concentration of
mercury, mercury concentration in  "ayu (sweetfish)" restored
cleanliness after one year, but in the case of dace it      took
four years to  lessen the value of mercury concentration.

2.2  CASE STUDIES ON PCB POLLUTION
    Production of PCBs  in Japan began in 1954, and by 1970  out-
put reached 11,000 tons  per year.   But the advent of    concern
over possible  pollution  brought the output down to 6,800    tons
in 1971, and in  1972 production was  totally halted.    PCBs had
also been imported prior to World War II, although statistics on
the quantity are not available.   During the period  from   1954
to 1972, the total amount of  PCBs use in Japan is estimated  ap-
proximately 53,000 tons.
                               105

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As to 2.2.1 (the case in Lake Biwa) and to 2.2.2 (the case in
Tsuruga Bay) another paper is prepared.
                              104 -

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Ill   REVISIONS  OF ENVIRONMENTAL  AND EFFLUENT  STANDARDS  ON
      MERCURY  AND SETTINGS OF  ENVIRONMENTAL AND   EFFLUENT
      STANDARDS  ON PCB

3.1  MERCURY
    Revisions  in the environmental  quality  standards  and  the
waste water discharge standards relating  to mercury  and  changes
in the relevant  measuring methods were enforced  on  Sept.   30,
1974.   This action was done on a report  presented to Director-
General of Environment Agency in April, 1974,  by  the   Central
Council for Control of Environmental Pollution.
3.1.1  Reasons for Amendment
    Under the  old environmental standards on water quality,both
alkyl mercury  and total mercury were to "not detectable".   But
quantities of  alkyl mercury smaller than  0.001 ppm could not be
measured by gas  chromatography and  thin  layer  chromatograph-
dithizon extraction absorptiometry, the procedures deemed  appr-
opriate when the standards were established in 1971-  Likewise,
there was a quantitative limit of 0.02 ppm for total mercury by
dithizon extraction absorptiometry, the procedure   practicable
for administrative purposes in those days.
    The "not detectable" level for  alkyl  mercury   was  set  be-
cause of adverse effects on the health that result from  eating
heavily contaminated fish and shellfish over a long  period  of
time and the difficulty of keeping  it out of tap water.
    In the case  of total mercury, the intake  from foods   was
subtracted from  the intake level beyond which the  metal  would
begin to accumulate in the human body, to figure out the intake
from drinking  water.   The "not detectable" limit  was institut-
ed by considering the intake ascribable to drinking water,  the
difficulty of  keeping the metal out of tap water,  and a  safety
margin.
    Both standards were not considered strict enough, but there
was no choice  but to be content with them because  of the limit-
                             - 105  -

-------
ed measuring capabilities at the time.   It was also in consid-
eration of these limitations that the effluent  standards   for
mercury were set at the same level as the water  quality stand-
ards when 10 times as much values as under the    environmental
quality standards were allowed for the discharge of other harm-
ful substances.
    Prompted by the following developments and in view  of  the
urgent need to resolve the mercury pollution issue, the  envir-
onmental quality standards and the waste water  discharge stan-
dards relating to mercury were revised to update themi (l)  Ad-
vances in analysis technology and the spread of more sophistic-
ated analysing devices have made it possible to analyse     low
densities of mercury; (2) Provisional tolerance levels of  mer-
cury were fixed for fish and shellfish; (3) More data on envir-
onmentalpollution and fish and shellfish contamination have be-
come available, permitting studies on the interrelationship be-
tween them.
     Note 1:  Technological advances— The measurable limit
  on total mercury by flameless atomic  absorptiometry  and
  on alkyl mercury by gas chromatography and thin     layer
  chromatograph-flameless atomic absorptiometry  has   been
  improved to 0.0005 ppm, remarkably better than before.
     Note 2:  Provisional tolerance levels on  fish     and
  shellfish— The maximum permissible levels    established
  provisionally by the Health and Welfare Ministry are  0.4
  ppm in total mercury and 0.3 ppm in methyl mercury.
     Note 3s  Environmental pollution and  fish  and shell-
  fish contamination— While surveys indicate that the mer-
  cury pollution of fish and shellfish has much more to  do
  with bottom sediments than with water,  it seems  safe  to
  say that if mercury levels in water are kept to the range
  of 0.00§ Ppm and 0.001 ppm, fish and shellfish  living in
  the sea, lakes and marshes can stay well below  the  pro-
                               106

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  visional limits.
3.1.2  Main Points of Revision
    The revised standards relating to mercury are given below.

                Revised Standards on Mercury
^^^
Environmental
A! 1 o 1 -i + -rr
v^uaj.iTy
Standards

Waste ¥ater
Discharge
Standards
^
Total
Mercury
Alkyl
Mercury
Total
Mercury
Alkyl
Mercury
Standard
Value
0.0005
ppm
2)
Not Detectable
0.005
ppm
4)
Not Detectable
Measuring
Method
Flameless Atomic
Absorptiometry
Gas Chromatography
and Thin Layer
Chromato graph—
Flameless Atomic
Absorptiometry
Flameless Atomic
Absorptiometry
Gas Chromatography
and Thin Layer
Chromatograph-
Flameless Atomic
Absorptiometry
     Note 1:   The standard value for total mercury stands for
   the annual mean value.   It is to be eased to 0.001 ppm  or
   less for rivers when there is no doubt that their  pollut-
   ion is spontaneous.
     Note 2:   The phrase "not detectable" applies to cases
   other than when the  presence of alkyl mercury is  detected
   by gas Chromatography and thin layer  chromatograph-flame-
   less atomic absorptiometry.
     Note 3:   ¥hile the waste water discharge   standard   of
                             107

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   0.005 for total mercury is 10 times as much as the  level
   allowed under the environmental quality standards,  waste
   water released into a normal body of vater is  presumably
   diluted quickly to reach readings satisfying the environ-
   mental quality standards.   Since the discharge limit ap-
   plies to maximum levels of pollution, the average quality
   of released waste water will have to be better than 0.005
   ppm.
     Note 4«  The discharge standard for alkyl       mercury
   should be kept as strict as under the environmental qual-
   ity standards because of its tendency to accumulate heav-
   ily in fish and shellfish.

3.2  PCB
    The water quality panel of the Central Council for Con-
trol of Environmental Pollution has submitted a report   on
standards to fight PCB pollution to the Director General of
the Environment Agency at the end of the year 1974.     The
panel's recommendations involved environmental water  qual-
ity standards relating to PCBs, relevant waste water   dis-
charge standards, provisional standards for removal of PCB-
contaminated sediments, and the analytical method   to   be
employed.
    The report was drafted in response to a request    from
the Environment Agency, which took the initiative to follow
up on the earlier instituted measures to curb mercury  pol-
lution.
    The agency's battle against PCB pollution has been bas-
ed on decisions made by the PCB Pollution Countermeasures
Council set up in April, 1972, and the Mercury    Pollution
Council created in June, 1973.   The discharge of      PCB-
tainted waste water has been regulated on the basisof  pro-
visional guidelines presentedin July, 1972,  while    broad
controls havebeen enforced on the production end    use  of
                             108

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PCBs under the Chemical Substances Control Law.
    In spite of these efforts, the PCB pollution of public  bod-
ies of water— resulting from the release of contaminated waste
water from such facilities as the workshops of waste      paper
dealers— persists.   Hence the agency's request for  consider-
ation of new anti—PCB measures.
    Here are the main points of the report on PCB     standards
from the water quality panel.
3.2.1  Basic Principles
    (l)  The guiding principles in establishing the    proposed
sets of standards should be to keep down PCB levels  in   water
and sediments so that the PCB level in fish and shellfish    —
whether accumulated directly from the contaminated  environment
or through the food chain— will not exceed 3 ppm as  the  pro-
visional limit for foods. (See note)
    (2)  Allowances should be made for particular conditions of
PCB pollution in diffrent public bodies of water and   for  the
accuracy of PCB measurements.
    (3)  Waste water discharge standards on PCBs should be est-
ablished by considering the related environmental quality stan-
ards and the way PCB-contaminated waste water spreads  when  it
is released from an outlet into a public body of water.
     Note:  The 3 ppm permissible limit on PCBs applies    to
  the edible parts of fish and shellfish caught in     inland
  seas, bays and other bodies of water.  The provisional rule
  was set on the basis of recommendations made  by  the  Pood
  Sanitation Research Committee to the Health  and    Welfare
  Ministry on Aug. 14, 1972.
3.2.2  Consideration of Belevant Factors
(l)  Concentration Ratio
    The following formula should be used as the definition   of
the ratio of PCB concentration in fish and shellfish,    a   key
                               109 -

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factor in relation to the proposed sets of standards:
   PCB concentration
     PCB density in edible  parts   of
     fish and shellfish
     PCB density in environmental water

    Table 1 shows PCB concentration ratios obtained from    ex-
periments using this equation.   The figures range from   5>607
to 8,582 and average 7,360.  A proper ratio would be     around
10,000, first because "hamachi" (young yellow-tails)  and eels,
the fish used in the experiments, are species more apt  to  ac-
cumulate PCBs and, second, because concentration ratios      in
cases where PCB densities actually pose a fish  and   shellfish
contamination problem— such densities would be a little  lower
than the range of one to five ppb, the PCB level of water    in
which the fish was kept— would be slightly higher than    what
the experiments showed.   A third factor to be considered    in
this connection is the food chain.
(2)  Measuring Methods for PCBs
    Gas chromatography should be used to measure PCBs in envir-
omental water.  The quantitative measurement limit  under  this
method is 0.0005 ppm.   As for PCBs in sediments, another meas-
uring method is prescribed.
3.2.3  Environmental Quality Limit on PCBs
    "Not detectable" is the recommendation on PCBs in  environ-
mental water,  because, while the provisional PCB limit    foods
(3 ppm) and the proper PCB concetration ratio (10,000)  suggest
a ceiling of 0.0003 ppm, gas chromatography makes it possible
to measure up to 0.0005 PPm.   PCB densities in water    should
be obtained by the following formula:
                               110  -

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  PCB density(ppm)
    PCB density  in edible parts  of  fish
    and shellfish (ppm)
    PCB concentration  ratio  in  fish  and
    shellfish
    3 ppm
           = 0.0003 ppm
    10,000
    The setting of the  "not detectable"  environmental  limit   is
not to be taken to mean  that pollution up  to 0.0005  ppm will  be
permitted.   Currently clean water  quality should be  protected
from degradation as much as possible.
3.2.4  Waste Water Discharge Standards
(l) Regulation Value— 0.003 ppm  in PCBe
    Based on the provisional PCB  limit for foods and the appro-
PCB concentration ratio, PCB densities in  environmental  water,
are to be held to 0.0003 ppm or less.    Since it is  safe      to
assume that discharged waste water  is diluted 10 times or  more
in a normal body of water, the regulation  value is to  be set  at
0.003 ppm.
(2) Enforcement of Rule
  A)  The stiffened rule is not be  enforced for a month   after
its promulgation to provide time  in which  to thoroughly  inform
industrial plants and other business establishments    of    the
change.  (Guidance has been exercised to keep PCB  readings   in
discharged waste water below the  earlier quantitative  limit  of
0.01 ppm under the above-mentioned  provisional guidelines.)
  B)  Toilet paper manufacturing  companies, using waste   paper
as material, are to be granted a  one-year  grace period in  view
of the particularly serious implication of the new rule     for
them in waste water disposal,.
(3)  Measuring during Grace Period
  A)  Targets for control of the  quality of waste water,   with
0.003 ppm as the permissible limit, are to  be fixed  for applic-
                              111

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ation to toilet paper producers during the grace period.
  B)  Administrative guidance is to  be  stepped  up  on  waste
paper collectors and manufacturers using  such  paper  so  that
PCB-containing "no-carbon" copying paper will be handled separ-
ately from other kinds of junk, will not get mixed in   product-
ion materials, and will be kept in strict custody once collect-
ed.
3.2.5  Provisional Standard For Removal of PCB- Contaminated
       Sediments
    Considering statistical analysis on the relationship   bet-
ween the PCB pollution of fish and shellfish and PCB  densities
in the same areas based on national environmental surveys, sed-
iments with a reading of around 10 ppm require removal.
    The present dredging technology should make it feasible  to
bring the contamination level down to about 10 ppm. The removal
standard ia thus to be set at 10 ppm.
    The imposition of tougher standards should be    considered
for bodies of water where the 10 ppm level is deemed inadequate
 to arrest the worsening PCB pollution of fish and shellfish.

IV   PROVISIONAL STANDARDS FOR REMOVAL OF CONTAMINATED
     SEDIMENTS

4.1  MERCURY^-CONTAMINATED SEDIMENTS
4.1.1  For Sea Area
    Provisional standards for removal of mercury-contaminated
sediments should be obtained by the following formulat

  C = 0.18 x -45- x -i- (ppm)

    Here,   C t Value of mercury density of sediments
           AH: Mean value of the difference of sea levels
                between ebb and flow (m)
            j : Dissolving ratio according to "the Method of
                              112

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                Survey for Bottom Sediment"
            s  t Safety factor
                  l)  10 for sea areas in  which  no     fishing
                      activities are performed.
                  2)  50 for sea areas in which fishing  activ-
                      ities are performed, and in the  case  that
                      the ratio of the catch for fish  and shel-
                      lfish which intake sediments  and   organ-
                      isms sticking to sediments to the   total
                      catch is approximately less than ^.
                  3)  100 for sea areas in which fishing activ-
                      ities are performed, and in the  case  that
                      the ratio of the catch for fish  and shel-
                      lfish which intake sediments  and   organ-
                      isms sticking to sediments to the  total
                      catch is approximately exceeding than ^.
                      Also, it is allowed that an adoption   of
                      stricter value of safety factor  according
                      to the special conditions, e.g., habit of
                      diet.
                      Here, "fish and shellfish which     intake
                      sediments and organisms sticking to sedi-
                      ments" are sorts of lobsters, crabs etc.
4.1.2  For Eivers and Lakes
    In the case of rivers and lakes, sediments with a   reading
of over 25 ppm require removal.   However, in the case of   est-
uaries which are strongly affected by ebb and flow, it    should
be applied correspondingly in the case of sea areas,   on   the
contrary in the case of sea areas which are affected   strongly
by the coastal current, it should be applied correspondingly in
the case of rivers and lakes.
4.2  PCS-CONTAMINATED SEDIMENTS
    As stated in the paragraph 3.2.5.
                               113

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                               Fourth US/JAPAN Conference
                                        on
                               Sewage Treatment Technology
                                     Paper No. 3
STUDIES  ON  ADVANCED  WASTE  TREATMENT
                   October 24,  1975
                   Cincinnati, Ohio
               Ministry of Construction
                 Japanese Government
                        - 114 -

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               STUDIES ON ADVANCED WASTE  TREATMENT
1.  Current and Future Studies on Advanced Waste Treatment in Japan	116
      M. Kashiwaya, PWRI, Ministry of Construction

2.  Outline of Research Activities on Advanced Waste Treatment in Public
    Works Research Institute, Ministry of Construction	120
      M. Kashiwaya, PWRI, Ministry of Construction

3.  Direct Filtration of Secondary Effluent          	124
      M. Kashiwaya, PWRI, Ministry of Construction

4.  Metal Salts Precipitation	156
      S. Ando, S. Kyosai and M. Kashiwaya, PWRI, Ministry of Construction

5.  Lime Precipitation and Recovery of Calcium Carbonate	205
      5. Kyosai and K. Murakami, PWRI, Ministry of Construction

6.  Carbon Adsorption and Regeneration of Waste Carbon       	227
      S. Ando and K. Murakami, PWRI, Ministry of Construction

7.  Breakpoint Chlorination  	        	         282
      H. Watanabe and K. Murakami, PWRI, Ministry of Construction

8.  Phosphate Removal in an Activated Sludge Facility by Alum Addition	295
      T. Annaka, K. KoboriandK. Murakami, PWRI, Ministry of Construction

9.  Pilot Plant Studies of Phosphorus Removal from Secondary  Effluent
    to Protect Lake Biwa  .   .        	      .       	       316
      A. Sugiki, Japan Sewage Works Agency
                                         -  115

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CHAPTER 1.  CURRENT AND FUTURE STUDIES ON ADVANCED
           WASTE TREATMENT IN JAPAN	117
                          116

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1.    CURRENT AND FUTURE STUDIES ON ADVANCED WASTE TREATMENT
     IN JAPAN
     In recent years in Japan, so many experiments of pilot plant scales for advanced
waste treatment have come to be carried out. These are roughly classified into the
following three cases.
i)    A case sponsored by the Central Government and assisted by local government
ii)   A case  conducted by local  government independently or in cooperation with
     manufactures
iii)   A case conducted by a manufacture alone

     Advanced waste treatment  now under study in Japan can be classified as to
objectives as follows.
i)    Experiment  for  upgrading  the secondary effluent from the activated sludge
     process
     Major studies include: study of the effects of coagulant dose into aeration tank,
     study of effects of coagulant dose on biological treatment, and study on the
     selection of filter type for direct filtration of secondary effluent and selection
     of their media sizes and conponents.
ii)   Experiment  on  tertiary treatment purposes for phosphorus removal from the
     secondary effluent
     So many pilot-scale experiments on chemical-sedimentation process using lime
     or metal salts as coagulants have been carried out.
     Purposes of the studies are: improvement of settling efficiency, improvement of
     phosphorus removal efficiency, improvement of organic matter reduction ef-
     ficiency, and thickening and dewatering of the sludge.
     Experiments on  recovery of used coagulant from settled  sludge have  not yet
     been reported.
iii)   Experiments for the removal of residual organic matter from secondary effluent
     Experiments on granular activated carbon adsorption of secondary effluent or
     effluent from chemical-sedimentation have  been reported one after another.
     Also, study on the regeneration for spent carbon is also prevailing.
     Granular activated carbon adsorption process has been practiced for the treat-
     ment of organic  type industrial wastes. There are many factories with a large-
     scale waste water treatment  facility equipped with  a regenerator for spent
     carbon.
     Oxidation  of organic matter of waste water by ozonation is rarely so long as
     the pilot plants  are  concerned, because the electric costs are so expensive in
     Japan.
iv)   Experiments on  biological nitrofication and denitrofication process.
     Experiments of  three-stage biological nitrofication and denitrofication has been
     carried out with  a pilot plant annexed to a small-scale sewage treatment  facility.
                                   - 117

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     This is because  the  secondary  effluent from the small-scale sewage treatment
     facility is discharged into irrigation channel and nitrogen in the effluent ham-
     pers the growth of rice plant.
     Strong opposition has  been made by the farmers against the pollution of their
     paddy fields with nitrogen.
     High concentration  of nitrogen in  the  supernatant developed from the night
     soil digestion facility is also warned against by the farmers.
     For this reason, demonstration plants for biological nitrofication and denitrofi-
     cation were installed at several places and are now in operation.
v)   Removal of ammonia by physico-chemical process
     Experiments on ammonia stripping, ion exchange of ammonium by making use
     of natural  zeolite, and breakpoint chlorination have been conducted at several
     places each.  Also, an  experiment in which  NOx in stack gas is reacted upon
     ammonia in sewage in  order to vent ammonia into the open air in the form of
     N2 gas is going to be started on  a pilot plant scale by a private company.
     There has  not been any trial for recovering ammonia in sewage in the form of
     industrial raw material  or fertilizer.
vi)   Experiments on the removal of inorganic substance in sewage
     In Japan,  water shortage  is expected  to take  place  in future in  Kanto and
     Kansai and other developed areas.
     Also, ground depletion areas (ground subsidence) have been reported increas-
     ingly as a result of overpumping of ground water.
     Against  this backdrop, move  toward  using as industrial  water  the  tertiary
     effluent of sewage has been intensified. Reflecting  the trend, a fair number of
     pilot plants using reverse osmosis or electrodialysis process have been operated.
     Also, many are struggling for the development of membrane  to be used for such
     processes.

     The Central  Government-subsidized public works projects concerning the ter-
tiary treatment  in FY 1975 (April 1975 ~ March 1976) are only  two; Minami-Tama
Sewage Treatment Plant  under the  Tamagawa Basin-Wide Sewerage Works, Tokyo
Metropolitan Government,  and  Tone Sewage Treatment  Plant under the Jonan
Basin-Wide Sewerage Works, Ibaragi Prefecture.
     Since  the  public waters in Japan  have been seriously polluted,  the Central
Government and  many local governments alike are  strongly urged to  upgrade  the
effluent discharged from sewage treatment plants.
     Such being the circumstances, the construction of tertiary  treatment facilities
will be pushed forward at most of sewage treatment plants.
     Japan is short of the under-ground natural resources, and a narrow, overpopu-
lated country. A population of more than 114 million live on the narrow country.
The national living mainly relies on imports of natural resources which are converted
into industrial products for export.
     Some  300  sewage  treatment plants installed in the past have all counted on the
biological process  using conventional or modified (including conpact types) activated
                                     118 -

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sludge process mainly.
     Most of the sewage treatment plants to  be constructed from now on will be
adopted conventional activated  sludge process as the secondary treatment process.
     Herewith, the sewage treatment system for the future should be the design that
is based on  the  saving of resources and energy, and should also be able to recover
materials contained in the sewage as much as we can.
     The studies on the advanced waste treatment  in Japan will therefore be guided
and promoted by the Central Government, local governments and private  manufac-
tures for the development of new  technology  meeting the said requirements with
paramount importance attached to the scarcity of resources and energy.
                                - 119 -

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CHAPTER 2.  OUTLINE OF RESEARCH ACTIVITIES ON ADVANCED
           WASTE TREATMENT IN PUBLIC WORKS RESEARCH
           INSTITUTE, MINISTRY OF CONSTRUCTION 	121
                           120

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2.   OUTLINE OF RESEARCH ACTIVITIES ON ADVANCED WASTE TREAT-
     MENT IN PUBLIC WORKS RESEARCH INSTITUTE, MINISTRY OF CON-
     STRUCTION
     Public Works Research Institute, Ministry of Construction, has carried out some
experiments  of  pilot  plant  scale  at  the  Shitamachi Sewage  Treatment  Plant,
Yokosuka,  and the Toba Sewage Treatment Plant, Kyoto, and with part of the ex-
isting facilities at the Nishiyama Sewage Treatment Plant, Nagoya.
     In  these field experiments,  engineers and  chemists of the Water Pollution
Control Division, Public Works Research Institute and of the Sewerage and Sewage
Purification Bureaus of respective cities have joined efforts for engineering, construc-
tion and operation control of pilot plants or actual facility as well as for the collec-
tion of  data. In  the meantime, the Water Quality  Control Division of the Public
Works Research  Institute  has undertaken a laboratory study for the  purpose  of
designing the pilot plant and complementing the  data obtained in the field studies.
     As reported at the 3rd U.S.-Japan Conference on Sewage Treatment Technolo-
gy held  in Tokyo on February,  1974, the members of the Joint Working Group on
Advanced Waste Water Treatment Technology which is composed of the engineers
and chemists from the Ministry of Construction and eight cities have also partici-
pated in the laboratory test of the chemical sedimentation process using lime and
metal salts, and have collected the data.
     At the  pilot plant  located  in the Shitamachi Sewage  Treatment Plant  in
Yokosuka,  chemical sedimentation process has been examined in  two  trains; one
using lime as a coagulant and the other using metal salts. In the lime-using chemical
sedimentation process test, quick-lime has been put to continuous slaking to make
coagulant. In the metal salts-using chemical  sedimentation test, various aluminum
salts and iron salts have been tried as coagulants.
     The experiments with  the  pilot plant  at the Shitamachi Sewage Treatment
Plant, Yokosuka, have been made for the comparison between various coagulants as
to the efficiency of chemical sedimentation process for removal of phosphorus and
organic  matter, study on  the method  of improving settling efficiency by trying
various coagulants and settling attachment, and tests for thickening and dewatering
of sludge containing coagulants.
     Also,  the Yokosuka  Municipal Government has conducted a study for con-
verting the effluent from the sewage treatment plant into industrial water by using
the effluent of the pilot plant. Recently, this study has been continued by applying
the granular activated carbon adsorption process and reverse osmosis process.
     Of the items reported hereunder, those concerning the lime sedimentation pro-
cess and metal salts sedimentation process use the experimental data mainly obtained
from the operation of this pilot plant.
     With the pilot plant located at the Toba Sewage Treatment Plant, Kyoto, direct
filtration,  granular activated  carbon adsorption and breakpoint  chlorination have
been studied. At present, a chemical sedimentation tank using metal salts as coagu-
lants is  under construction to add to the existing facilities, and the experiment is
scheduled to be started in September this year.
                                     121

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     The Toba Sewage Treatment Plant in Kyoto is one of the most largest sewage
treatment plants in Japan, and is  featured in that its influent BOD concentration
mixed with supernatant of sludge treatment process is as high as 200 to 350 mg/lit.
     The application of the secondary effluent of the Toba sewage treatment plant
to the pilot plant for study purposes is advantageous in  that experimental data for
the case where sewage is flowing into the sewage treatment plant at a design rate can
directly be obtained. In general, BOD concentration of the raw sewage running into
the sewage treatment plants are expected to rise more and more in the future in our
country.
     In view of these facts, the tertiary pilot plant studies at the Toba Sewage Treat-
ment Plant in  Kyoto will have a great significance on the preparation of manual for
engineering,  operation and maintenance of the tertiary  facilities to be installed at
sewage treatment plants in Japan.
     The experiments with the pilot plant at the Toba Sewage Treatment Plant,
Kyoto, have embraced studies on the development and upgrading to a practical level
of instrumentations and automatic control system and  for the tertiary treatment
facilities.
     The down flow gravity type filter and the chemical sedimentation tank using
metal salts as  coagulants which is going to enter upon operation in September this
year are  designed to freely control the filtration flow rate of the filter and the in
flow of the chemical  sedimentation tank on current signals from the program trans-
mitter.
     Also, the composite  samplers of the  influent and  effluent of the filter and
chemical sedimentation tank  are designed to  operate on the signals  from  the same
program transmitter.
     Of the items reported hereunder, those concerning direct filtration of second-
ary effluent,  activated carbon  adsorption  process, and  the regeneration of spent
carbon as well as the breakpoint chlorination process are  based on the data acquired
from this pilot plant.
     Also, the  data from this pilot plant are used in "Automatic Water Quality Meas-
urement for Wastewater Treatment."
     The Nishiyama  Sewage Treatment Plant, Nagoya, is treating domestic sewage
only with a design sewage flow of 30,000 m3/d.. Raw sewage of 20,000 to 22,000
m3  per day is flowed  into the treatment at present.
     The plant is composed of two  primary  sedimentation tanks, two aeration tanks
and three final sedimentation  tanks (of which two have been used for this experi-
ment).
     As sludge treatment  is not carried out in this treatment plant, supernatants
from the sludge treatment facility are not sent into the primary or secondary treat-
ment process.
     As regards one train in the treatment plant, a  experiment of dosing aluminum
sulphate into the  aeration  tank has been made. Another train has  been used as a
control and operated under conventional activated sludge process. In the Nishiyama
Sewage Treatment Plant,  these investigations have been carried out:  purification
                                     122

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effects of aluminum sulphate dose into aeration tank, influence of aluminum sul-
phate dose on the organisms and  their biological activities in the  activated sludge
process, and measurement of sludge productions in the primary sedimentation tanks
and  final  sedimentation tanks by means of magnetic flowmeters and ultrasonic
sludge concentration meters. It is  to be added by the way that one  train of auto-
matic backwashing filter comprising 8 compartment vessels is scheduled to be put in
operation in September this year.
     Of the items reported  hereunder, those concerning "phosphate  removal in an
activated sludge  facility by alum addition" are based on the data obtained from the
Nishiyama  sewage treatment plant,  Nagoya. Also, "Study  on the treatment and
disposal of sludge" uses data acquired by the investigations at this plant.
     Since  the beginning of  FY 1975, the Public Works Research Institute has been
conducting laboratory studies for nitrofication and denitrofication  of municipal
sewage. Especially,  the  subject of nitrofication study is first stage  nitrofication by
using the primary and secondary treatment facilities only of those sewage treatment
plants which are operated on the conventional activated sludge process. If the labor-
atory study is successful, it will be amplified into field experiments at the Nishiyama
Sewage Treatment Plant.
                                   - 123

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     CHAPTER 3.  DIRECT  FILTRATION OF SECONDARY  EFFLUENT
3.1    Effects on the Filtration and Washing of the Ratio of the Depth of
      Anthracite to the Total Depth of Media  in  the  Down-Flow Type
      Gravity Dual Media Filter .      . .     	125
3.2    Effects on the Filtration and Washing of the Difference between Dual
      Media and Mixed  Media in the Down-Flow Type  Gravity Declining
      Filtration   	     	  126
3.3    Effects of the Sizes of Media in the Down-Flow Gravity Filter on the
      Filtration and Washing    	               	  127
3.4    Comparison of Filtration Effects between Constant Flow-Rate Filtra-
      tion  and Declining Flow-Rate  Filtration  in  the Down-Flow Type
      Gravity Dual Media Filtration      	128
3.5    Comparison of Filtration Effects between  the Variable Flow-Rate
      Filtration and Declining Flow-Rate Filtration in the Down-Flow Type
      Gravity Dual Media Filtration	     	12g
3.6    Merits and Demerits of Up-Flow Filter	              	  130
                                    124

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3.   DIRECT FILTRATION OF SECONDARY EFFLUENT
     The Kyoto Pilot Plant now jointly experimented with by  the Ministry of
Construction and the Kyoto Municipal City has three down-flow type gravity filters
and one up-flow type filter, each measuring 1.0 m in width, 1.2 m in depth and 3.75
m in height.
     Various field  studies concerning direct  filtration  of secondary effluent have
been carried out by using these  four pilot filters, and some of the findings were
reported at the 3rd U.S.-Japan Conference on Sewage Treatment Technology held in
Tokyo on February 1974.  Later, the pilot filters  were modified  partly. The data
appearing  in this report  are obtained from  the  experiments following the flow
chart shown in Fig. 3.1.
     What is changed  from the  system reported previously is the installation of a
various  flow-rate pattern transmitter whose output signal is used to control one of
the down-flow type gravity filter. The Roots pump connected to the effluent pipes
of this filter is feedforward controlled by the current signal from the flow pattern
transmitter, and at the same time feedback controlled by the current signal from the
automatic level gauge on the triangle weir  of the effluent measuring tank.
     At the end of August this year, two other down-flow type  gravity filters were
equipped with  a Roots pump and an electric circuit for the same control operation
as above.
     As regards the up-flow type filter, which was found as explained later having
troubles with the experiment, a  separate test has  been made independent of the
down-flow type gravity filters.

3.1   EFFECTS  ON THE  FILTRATION  AND WASHING OF  THE RATIO OF
     THE  DEPTH  OF ANTHRACITE TO THE TOTAL DEPTH OF  MEDIA IN
     THE DOWN-FLOW TYPE GRAVITY DUAL MEDIA FILTER
     Part of the results concerning this investigation  was reported at the 3rd U.S.-
Japan Conference on  Sewage  Treatment Technology held in  Tokyo on February
1974. Since  then, the investigation has progressed, and the following conclusions
are reached.
     The effective  size and coefficient of uniformity of the media used  in the test
are  as shown in Table 3.1. The  listed media were filled  up  into  the filter  No.  1
(type I) and the filter No. 2 (type II) shown in Table 3.2.
     The test was conducted on the declining filtration only; both filters got started
at the same time, and  when a  maximum  filtration head loss of 3.0 m was attained,
they were stopped. After  the other filters completed filtration, they were washed in
turn, and were restarted to resume filtration test.
a.    As shown in Table 3.3, the filtration run length at filtration flow rate of 180
     m3/m2 .d.  to 420 m3/m2 .d. was about twice as long in type II as in type I. It
     was found by means of a head loss meter set in the media that anthracite layer
     has a larger capability of holding suspended solids in the secondary  effluent
     than silica  sand layer.  It  is therefore more advantageous, in  the light of the
     filtration run length, the larger the thickness of anthracite layer is.
                                     125

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b.   Type I and type II are compared in Table 3.4 with respect to filtrate quality
     and their removals.
     There is no significant difference between the two.
c.    The initial head losses of clean media were compared. For a filtration flow rate
     of  360 m3/m2. d., for example,  the  filter arrangement of type I  caused an
     initial head  loss of 54 cm, while  the arrangement in type II recorded 36 cm.
     The difference was 1.5 in ratio.
d.   It was  confirmed that with the most suitable expanded bed ratio set at 20%
     in the back washing, the back washing rate for type II can be o.71 m3 /m2. min.
     as against 0.87 m3 /m2. min. for type I.
     The larger the expanded bed ratio becomes, the larger is the difference in back
     washing rate between the two.
e.    It takes either type 10 to  12 min. to complete back washing.
     For either type, surface washing is  indispensable.
f.    Washing volume/filtrate volume ratio reached 2.3 to 3.2% in case of type I filter
     arrangement, but was  1.1  to 2.0% in type II filter arrangement.
     It is therefore concluded that the  depth of the anthracite layer be maximized.
At any rate, the depth of the anthracite layer should be more than 60% of the total
depth if it is used in the direct filtration down-flow type gravity filter.
     The maximum ratio of anthracite  layer depth to the total media depth, above
65%, has yet to be studied.

3.2  EFFECTS ON  THE  FILTRATION AND WASHING OF THE DIFFERENCE
     BETWEEN  DUAL MEDIA AND MIXED MEDIA IN THE DOWN-FLOW TYPE
     GRAVITY DECLINING FILTRATION
     Like  item 3.1,  this was also reported  with some results at the 3rd U.S.-Japan
Conference on Sewage Treatment Technology held in Tokyo on February  1974.
     Since then,  additional experiments have been carried out, and the following
conclusions are reached.
     The  effective size and coefficient of uniformity of the media  used  in the
experiments are as given in Table 3.1. The media were filled up in filter No. 2 (type
II) and filter No. 3 (type III). Sizes of the media shown in Table 3.1 were brand new
ones. When preparing the mixed media, they were brought into the filter in several
hauls, and each  time back washing was carried to remove fine grains.  Thus, the
effective size and coefficient of uniformity were changed accordingly. In type II,
back washing was carried out after the media were filled up totally; namely, fine
grains over the surface of the anthracite  layer alone were removed.
a.    As shown in Table 3.3, the filtration  run length at  filtration flow rate of 180
     m3/rn2. d.  to  420m3/m2   d. tended to become a  little longer in  type II
     arrangement than in type III.
     The time  history of the readings of the head loss meter set inside the filter in
     order to  evaluate the capacity of obstruction  of suspended solids  in the
     secondary effluent remained almost common to both types.
                                    -  126

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b.   The filtrate quality and their removals are compared between type II and type
     III in Table 3.4. As is clear, type II was a little better in filtrate quality than
     type III.
     In type III, the lowermost layer was formed with garnet sand having an effec-
     tive size of 0.32 mm., but it was not found the effect of the garnet layer by the
     readings of the head loss meter.
c.   The  initial head  losses of  clean  media were compared. At  filtration flow
     rates of not  exceeding 240m3/m2. d., there was little or no change in the
     initial head loss. At 360 m3 /m2. d., type III showed some 3 cm larger loss than
     type II.
d.   When the  most suitable expanded bed ratio of media in  the back washing was
     set at 20%, both types revealed a back  washing flow rate of 0.71 m3/m2  min.
     For both types, 10 to 12 min. of back washing time was necessary. The surface
     washing was indispensable for both  types.
e.   In most cases, the washing volume/filtrate volume ratio was a thought smaller
     in type II than in type III,  which would reflect the fact that  type II took a
     little longer filtration run length.
     It was  found  that the filtration effect of the mixed media is a little inferior to
the dual media type using the same sizes of anthracite and silica sand. It still remains
obscure whether this is due to poor selection  of size  or ascribable to the way of
arranging the mixed media layers.
     It is conjectured that so  long as the direct filtration of secondary effluent is
concerned, there would not be developed any  remarkable difference between the
dual media and mixed media even if an improvement is achieved.

3.3  EFFECTS OF THE SIZES OF MEDIA  IN THE DOWN-FLOW TYPE GRAVI-
     TY FILTER ON THE FILTRATION AND WASHING
     After comparative study on filtration  performance of three types shown in
Table  3.2, tests were carried out on different media with filters No. 1 and No. 2.
The  effective size and coefficient of uniformity of new media are given in Table 3.5.
The  constitution of the filter bed of the filters  No. 1 and No. 2 in shown in Table
3.6.  As regards the declining filtration,  comparison study was made with respect to
the difference in the size of media  between the filter No. 3 (type III) and filter No. 2
(type IV). The results are as follows.
a.   The difference in head loss curve between the two, time variations of filtration
     flow rate, and change of filtrate  turbidity  are shown in  Figs. 3.2  and 3.3.
     The difference in filtration run length in the declining filtration was larger with
     an initial filtration flow rate of 420 m3/m2  d. than 180 m3/m2. d.  The de-
     crement of the filtration flow rate  with time was also larger with 420 m3/m2
     d. than 180m3/m2 d.
b.   Irrespective of the filtration  flow rate, type III showed  a little better filtrate
     turbidity than type IV as shown in Figs. 3.2 and  3.3. The same held true with
     suspended solids, BOD and COD,,  as given in Table 3.7 and 3.S., though the
                                     127 -

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     difference was very small.
c.   In type III, the back washing flow rate necessary for attaining a expanded bed
     ratio of 20% was 0.7] m3 /m2. min., while type IV required 1.03 m3 /m2. min.
     The time necessary for the back washing was almost the same for both.
d.   Both types showed no difference in the washing volume/filtrate volume ratio
     when operated at a filtration flow rate of 180 m3 /m2. d.
     However,  type IV  showed smaller ratio than type III, the larger the filtration
     flow rate became.    '
     It is therefore concluded that the effective size of anthracite should preferably
be more than 1.6 mm. just as with type IV. This is particularly  the case when the
operation is carried out at a high filtration flow rate.

3.4  COMPARISON OF  FILTRATION EFFECTS BETWEEN CONSTANT FLOW-
     RATE  FILTRATION AND DECLINING FLOW-RATE FILTRATION IN THE
     DOWN-FLOW TYPE GRAVITY DUAL MEDIA FILTRATION
     A comparative study was conducted on type IV (declining flow-rate filtration)
and type V (constant flow-rate filtration). The results are as follows.
a.   For the initial filtration  flow rate, 180 m3 /m2. d., shown in  Fig.  3.4, there was
     little or no diffference in the total head loss during filtration.
     In the  case of declining  flow rate filtration, however, the filtration flow-rate
     was decreased to  120 m3 /m2. d. when the total head loss reached 3.0 m.
b.   For the initial filtration  flow-rate, 420 m3 /m2. d., shown in Fig. 3.5, filtration
     run length caused  a difference of some 12 hrs. It  became longer when the
     declining flow rate  filtration was practised.  In the declining flow rate filtration,
     however, the  declining  of filtration flow-rate was noticeable; when the total
     head loss was 3.0 m in the constant flow rate filtration, the declining flow rate
     filtration had a reduced filtration flow rate of 280 m3 /m2  d.
     When the  total head loss in the declining flow rate filtration reached 3.0 m, the
     filtration flor  rate became 240 m3/m2   d. or 57% of the  initial filtration flow-
     rate.
c.   As regards the turbidity, suspended solids, BOD and CODMn listed in Table 3.7
     both types showed little or no difference in the filtrate quality.  In the case of
     direct   filtration,  the declining flow-rate filtration was  not effective in  im-
     provement of  filtrate quality any more than the constant flow-rate filtration.
d.   As regards the washing volume/filtrate volume ratio, the constant flow rate filt-
     ration was better than the declining flow-rate filtration.
     The employment of declining flow rate filtration in the direction of secondary
effluent faces  various  difficulties in the planning of the filter. Considering the fact
that  it is by  no means excellent than the constant flow rate filtration, its employment
is quite meaningless.
                                     128  -

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3.5  COMPARISON  OF FILTRATION  EFFECTS  BETWEEN THE VARIABLE
     FLOW-RATE FILTRATION AND  DECLINING FLOW-RATE FILTRATION
     IN THE DOWN-FLOW TYPE GRAVITY DUAL MEDIA FILTRATION
     A flow pattern transmitter was installed for the filter No. 1 in order to give a
typical flow pattern of secondary effluent in the sewage treatment plant upon which
to operate the filter. This was type V. A comparison study was made between type
V and type IV in declining flow rate filtration. The flow pattern curve applied to the
testing of type V was based on  the measurements taken from the Toba Sewage
Treatment Plant.  The flow pattern transmitter generated a pattern for a filtration
flow rate of 300 m3 /m2. d. When the mean filtration flow rate was to be changed
from the above value, the  flow pattern was changed in proportion to the deviation.
In the event that the filtration flow-rate was  larger than 300 m3/m2. d., the dif-
ference between the  maximum and the minimum flow rate became large, while the
difference became smaller if the rate smaller than 300 m3 /m2. d.
     The results obtained with the mean filtration flow rates of 180 m3/m2. d., 240
m3 /m2  d., 300 m3 /m2 . d., 360  m3 /m2. d., and 420 m3 /m2. d. are shown in Figs.
3.6,  3.7, 3.8, 3.9 and 3.10, respectively.
     The results are as follows.
a.   The filtration run length becomes  smaller in the variable flow-rate filtration
     than in declining flow rate filtration.
     The difference however is small in case of the mean filtration flow rate is 180
     m3 /m2. d. and  420 m3 /m2. d.  For other rates, the difference is remarkable.
     Generally, the smaller the inflow of suspended solids into  the filter, the smaller
     the difference in filtration run length between variable flow-rate filtration and
     declining flow rate filtration.
b.   The total  filtration head loss in the variable flow rate filtration changes with
     the media's capacity  to detain suspended solids,  irrespective of the value of
     mean filtration  flow  rate, the total filtration head loss increases sharply with
     increase in the filtration run  length. This tendency is more stronger the larger
     the mean filtration flow-rate becomes.
c.   The filtrate quality in the variable flow rate filtration is a little inferior to  that
     in  the  declining flow-rate  filtration, though the difference is  very small as
     shown  in Table 3.8.  This tendency also applies to those  other than turbidity
     given in Figs. 3.6 through 3.10.
d.   As regards the washing volume/filtrate volume  ratio, there is seen little or no
     difference between the variable  flow rate  filtration  and declining  flow  rate
     filtration.
     All these suggest high feasibility  of variable flow-rate filtration for the direct
filtration of the secondary effluent, signifying that the variable  flow-rate filtration is
worth further examination. Since  the influent of the sewage treatment plant varies
largely at all hours, installation of a regulating  reservoir for direct filtration of sec-
ondary  effluent would be necessary if constant  or  declining  flow-rate filtration is
practiced at a  sewage  treatment  plant.  For this reason, the practice of variable
                                    129

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flow-rate filtration within the range of not degrading the filtrate quality is quite an
economical technique for polishing the secondary effluent.
     So far this kind of filtration technique has not been taken up seriously. If the
variable flow rate filtration is found to be able to raise a required efficiency, the
polishing of the secondary effluent will be feasible at any sewage treatment plant
economically.
     With this in mind, the experiments with the down-flow type gravity filter on
the direct filtration of secondary effluent will be continued with priority given to
the experiments of variable flow-rate filtration.

3.6  MERITS AND DEMERITS OF UP-FLOW FILTER
     The up-flow filter has been developed in the Luton Sewage Treatment Plant
and the Blackbird Sewage Treatment Plant in Britain.
     This  type of filter permits the use of influent directly for the back washing.
Also, it dispenses with post aeration as dissolved oxygen concentration in the filtrate
becomes high.
     For this reason, an up-flow filter having a filter area of 1.2 m2 was installed at
the Kyoto Pilot  Plant, and has been experimented with. The media size and depth
are shown  in Table 3.9. On top of the filter,  a grid was placed for the purpose of
suppressing the expansion of bed.
     The results of experiments with this filter and considerations are as  follows.
a.   As shown  in Table 3.10, the filtration run length for the maximum filtration
     head loss to reach 3.0 m  was 20 to  30% longer  compared with the declining
     flow rate down-flow filter (type II). Whereas the up-flow filter is to  be operated
     at a  constant  flow-rate filtration, the up-flow filter under consideration got
     directly connected with a influent booster pump as shown in Fig. 3.1, whereby
     the filtration flow-rate was reduced during operation. The decrement  of the
     filtration  flow  rate  was less than  one-fifth the declining  flow  rate  down-
     flow type filter's. (See Fig. 3.11)
b.   The total filtration head loss curve of the up-flow  filter under normal operating
     conditions is shown in Fig. 3.11.
     This filter caused leakage locally in its filter bed, and the increase of the total
     head  loss was stopped accordingly. Naturally, the suspended solids concentra-
     tion in the  filtrate rose up. An example of this phenomenon is shown in Fig.
     3.12.
     This kind of leakage phenomenon happens for certain irrespective of the filtra-
     tion flow-rate. The causes are still unknown.
     Morigasaki  Sewage  Treatment Plant, Tokyo,  is  installed with two up-flow
     filters,  each  having a filter  area of 30 m2, which have been used for testing.
     These filters also have experienced leakage.  The Sewage Bureau of the Tokyo
     Metropolitan Government has been pushing forward a survey for the improve-
     ment of washing technique and for the feasibility of preventing the bed leakage
     by limiting the total filtration head loss to 2.8 m.
c.    As regards the turbidity, suspended solids,  BOD  and  CODMn listed in Table
                                    - 130

-------
     3.11. Up-flow filter showed little or no difference as compared with down-flow
     declining filter in the filtrate quality.
d.   In the up-flow filter, the bed is put to cleaning by air agitation and back wash-
     ing in combination. The experiments with the up-flow filter in the Kyoto Pilot
     Plant disclosed that the cleaning  is  not sufficient  if air agitation and back
     washing alone are  counted upon.  For this reason, the following method was
     tried.
     Draining of filter bed - Air agitation (4 min.) - Rest (2 min.) - Air agitation
     (4 min.) - Water pulsating washing (20 sec.) - Rest (1  min.) - (10 repetitions
     of water pulsating  washing and rest in combination) - Water back washing (10
     min.) - Water level depression in filter bed - Water back washing (10 min.) -
     Start of filtration
     Although the above cleaning procedure has been  tried, it still is uncertain
     whether the media arrangement is warrantable to always keep  the filter bed
     clean and to prevent leakage phenomenon.  There is a fear of causing a great
     quantity of overflow of media from the washed water trough as the entire filter
     bed comes afloat in the pressurized water unless the  filter bed is  monitored all
     the  way from the  beginning  of water pulsating washing. In  the experiments
     with the up-flow filter at the Kyoto .Pilot Plant, less importance was attached
     to the flotation of the filter bed, and there has been experienced  overflow of a
     great amount of media from the washed water trough several times.
e.   At the Morigasaki  Sewage Treatment Plant, Tokyo, investigations have been
     made as to the cleaning method of up-flow filter bed.
     As a result, the following technique is proposed as best.
     Draining of  filter bed — Air  agitation (6 min.)  and water back washing (10
     min.) in combination (the final four min. for water back washing only) — Air
     agitation (6 min.) and water back washing (12 min.) in combination (the final
     six min. for water back washing only) — Rest (5 min.) — Start-up of filtration
     It is claimed that  the rest prepared in the final stage is indispensable for the
     stabilization   of  media  and   consequently  for the  prevention of  leakage
     phenomenon.
f.    The same cleaning method as in the Morigasaki Sewage Treatment  Plant has not
     been tried in the  Kyoto Pilot Plant as the combined use of air  agitation and
     water back washing necessitates a  large scale modification of electric control
     circuit used for the up-flow filter.
     As the  past  experiments suggests,  it is evident that sudden application of'air
     agitation and water back washing" can cause a great deal of overflow of media
     from the washed water trough as the media are buoyed.
     The overflow trouble due to water pulsating washing or back washing may be
     peculiar only to small-scale filters like one in the Kyoto Pilot Plant. In a large
     scale up-flow filter, the media may not be  buoyed uniformly at the time of
     water  washing.  Once in a while,  the Morigasaki Sewage Treatment Plant,
     Tokyo, has been processing only a limited quantity of influent,  and the con-
     centration of suspended solids in the secondary effluent is less than 10 mg/lit..
                                      131

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On the other hand, the concentration  of suspended solids in  the  secondary
effluent of the Toba Sewage Treatment Plant is Kyoto is as high as 25 to 35
mg/lit. Some fear that if secondary effluent containing high ratio of suspended
solids like this is directly filtered, the media separation would become difficult
because of  adhesive  power  developed  by suspended solids between media
particles.
These doubts will be clarified by further investigations.
The up-flow filter in Kyoto Pilot Plant requires some 1 hr. for washing of filter
bed. On the other hand, the Morigasaki's is some 40 min.  Then, the down-flow
filter requires less than  20  min. even if  surface washing and back washing are
carried out in combination.
The washing water volume  for the up-flow type filter is about 2.2 to 3 times as
large as that for the down-flow type. It  is evident  that the down-flow filter is
superior  to  up-flow  filter  when viewed  from  the washing volume/filtrate
volume ratio.
As discussed in the  foregoing, the up-flow filter has various problems to solve
before  it will be put to practice. For the purpose of direct filtration of seconda-
ry effluent, further investigations are necessary.
The authors have continued experiments  with the up-flow  filter believing in the
fact that  it permits the use of influent for washing purposes, which is hardly
expected  of the down-flow  filter. The authors will continue efforts for refining
the up-flow filter until it can stand practical use.
                                132  -

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Table 3.1   Media Size Using Experiment of Down
           Flow Type Gravity Filters
Media
Anthercite coal
Silica sand
Garnnet sand
Effective size (mm)
0.95
0.64
0.32
Uniformity coefficient
1.48
1.50
2.16
                         133

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              Table 3.2   Media Depth Using Experiment of Down  Flow
                         Type Gravity Filters (Type I, II and III)
               of experiment
v-
Kinds
                                   Type I
                                   No. 1
                    Type II
                    No. 2
                   Type III
                    No. 3
   Anthercite coal
  1 50 (mm)
 625 (mm)
 625 (mm)
   Silica sand
 850
 375 (mm)
 300
   Gamnet sand
                                       75
   Total
1,000
1,000
1,000
   Type of filtration
 Declining
Declining
Declining
                                       134

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Table 3.3   Operational  Data  of Filtration Run Length of Down  Flow Pilot Filters
           (Max. Total  Head Loss 3.0 meter)
                                                                                   (hrs)
Types of
experiment
Type I
Type II
Type III
Used
filter
Filter
No. 1
Filter
No. 2
Filter
No. 3
Items
Max.
Min.
Ave.
Max.
Min.
Ave.
Max.
Min.
Ave.
Flow-rate (m3/m2-d)
180
62:00
6:33
32:93
125:25
11:25
71:55
129:00
31:00
69:23
240
54:75
9:75
28:96
101:50
7:50
53:17
94:00
22:25
58:49
300
50:30
9:75
20:92
125:25
21:75
48:07
113:50
23:25
40:00
360
36:25
4:00
21:40
65:75
4:50
38:80
57:75
7:50
33:32
420
47:67
7:00
20:33
100:00
12:50
50:00
94:00
9:15
37:70
                                        -  135

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Table 3.4  Operational  Data of Down Flow Pilot Filters (Water Quality of Influents and Effluents and Their Removals)
^\\^~~^ 	 __Typeof experiment
^\"\^_JJse^^
Items ^-^™fr^^
Turbidity
Sus. solids
BOD
CODMn
Cone.
(mg/C)
Inf.
Eff.
Removal (%)
Cone.
(mg/ej
Inf.
Eff.
Removal (%)
Cone.
(mg/e)
Inf.
Eff.
Removal (%)
Cone.
(rng/2)
Inf.
Eff.
Removal (%)
Type I
Filter No. 1
180
8.4
2.9
65.5
13.3
4.0
69.9
22.8
7.9
65.4
17.0
14.5
14.7
240
6.6
2.3
65.2
12.8
3.7
71.1
19.4
4.8
75.3
15.1
11.8
21.9
300
6.9
2.5
63.8
•11.5
3.4
70.4
21.2
4.9
76.9
14.5
12.1
16.6
360
7.8
3.1
60.0
14.6
4.5
69.2
27.2
6.8
75.0
16.1
12.5
22.4
420
7.8
5.5
29.5
15.0
5.9
60.7
20.6
7.2
65.0
15.0
12.6
16.0
Type II
Filter No. 2
180
8.0
3.7
53.8
12.9
5.2
59.7
22.9
6.9
69.9
17.3
14.5
16.2
240
6.5
2.8
56.9
12.5
3.2
74.4
17.9
5.3
70.4
15.0
12.1
19.3
300
6.9
2.9
60.0
12.0
4.4
63.3
21.8
6.0
72.5
15.7
12.1
22.9
360
8.4
3.2
64.4
14.0
3.7
73.5
25.3
7.6
70.0
16.2
13.0
19.8
420
8.1
5.3
34.6
12.7
6.0
52.8
17.1
7.4
56.7
15.3
12.9
15.7
Type III
Filter No. 3
180
7.9
4.1
48.1
13.0
4.0
69.2
22.8
7.2
68.4
16.7
15.8
5.4
240
6.6
2.8
57.6
12.5
3.6
71.2
17.6
4.6
73.9
15.1
12.8
15.2
300
6.8
3.1
54.4
12.1
4.5
62.8
23.8
7.2
69.7
15.7
12.9
17.8
360
7.9
3.2
59.5
12.8
4.3
66.4
23.0
7.9
65.7
15.9
12.9
18.9
420
7.7
5.8
24.8
13.2
5.6
57.6
16.8
6.7
60.1
13.9
13.1
5.8

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Table 3.5  Media Size Using  Experiment of Down Flow Type Filters
Media
Anthercite coal
Silica sand
Effective size (mm)
1.62
0.605
Uniformity coefficient
1.327
1.256
                           -  137

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Table 3.6  Media Depth Using Experiment of Down Flow Type Gravity Filters
          (Type IV, Type V and Type VI)
^:^\-~~^^Type of experiment
^---_ __Used fijter
Kinds of media — "^"^^-^__
Anthercite coal
Silica sand
Total
Type of filtration
Type IV
No. 2
625 (mm)
325
1,000
Declining
Type V
No. 1
625 (mm)
325
1,000
Constant
Type VI
No. 1
625 (mm)
325
1,000
Variable
                                  - 138  -

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Table 3.7  Operational Data of Down Flow Pilot Filters
           (Water Quality of Influent and Effluent and Their Removals)
xj>^^^^ Types of Experiment
\^\ Used Filter
Items \Flow-rate(rn3/m2-d)
Turbidity
Sus. Solids
BOD
CODMn
Cone.
(mg/1)
Inf.
Eff.
Removal (%)
Cone.
(mg/D
Inf.
Eff.
Removal (%)
Cone.
, (mg/1)
Inf.
Eff.
Removal (%)
Cone. Inf.
(mg/1) | Eff.
Removal (%)
Remarks
TypeV
Filter No. 1
180
3.9
2.1
46.2
6.4
2.5
60.9
14.9
6.1
59.1
15.7
14.6
7.0
240
4.3
3.0
30.2
4.5
4.0
11.1
6.0
4.4
26.7
17.9
17.4
2.8
300
2.7
2.2
18.5
3.0
3.0
0
6.0
2.8
53.3
14.0
(16.2)
360
-
_
_
_
420
2.8
2.1
25.0
3.2
2.1
34.4
20.1
12.6
37.3
17.7
16.3
7.9
Constant Flow-rate
Type IV
Filter No. 2
180
3.9
2.5
35.9
6.4
2.7
57.8
14.9
4.6
69.1
15.7
14.3
8.9
240
4.3
3.1
27.9
4.5
3.8
15.6
6.0
4.5
25.0
17.9
16.2
9.5
300
2.7
2.5
7.4
3.0
(3.1)

6.0
3.0
50.0
14.0
(16.7)
360
-

-
~
-
420
2.8
2.3
17.9
3.2
2.5
21.9
20.1
13.1
34.8
17.7
15.6
11.9
Declining Flow-rate
Type III
Filter No. 3
180
3.9
2.6
33.3
6.4
3.0
53.1
14.9
5.9
60.4
15.7
14.2
9.6
240
4.3
3.2
25.6
4.5
4.1
8.9
6.0
5.9
1.7
17.9
16.8
6.2
300
2.7
2.6
3.7
3.0
2.6
13.3
6.0
3.5
41.7
14.0
(19.7)
360
-
_
:
-
420
2.8
2.3
17.9
3.2
2.2
31.3
20.1
12.9
35.8
17.7
16.9
4.5
Declining Flow-rate

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                                                    Table 3.8  Operational Data of Down Flow Pilot Filter

                                                              (Water Quality of Influent and Effluent and Their Removals)
N^\~~^^^ Types of Experiment
x\
Used Filter
Items ^\J;l°w-rate (m3/m2-d)
Turbidity
Sus. Solids
BOD
CODMn
Cone.
(mg/1)
Inf.
Eff.
Removal (%)
Cone.
(mg/1)
Inf.
Eff.
Removal (%)
Cone.
(mg/1)
Inf.
Eff.
Removal (%)
Cone.
(mg/1)
Inf.
Eff.
Removal (%)
Remarks
Type VI
Miter No. 1
180
5.4
3.5
35.2
7.5
3.9
48.0
19.3
6.0
68.9
25.0
22.7
9.2
240
5.6
4.2
25.0
7.1
5.2
26.8
12.7
6.5
48.8
21.8
17.7
18.8
300
4.4
2.7
38.6
5.5
4.0
27.3
20.7
10.0
51.7
20.7
16.4
20.8
360
8.2
5.3
35.4
9.8
6.6
32.7
17.5
7.3
58.3
20.5
16.7
18.5
420
6.2
4.3
30.7
9.0
7.5
16.7
16.5
9.4
43.0
24.2
22.7
6.2
Variable Flow-rate
Type IV
Filter No. 2
180
5.4
3.5
35.2
7.5
3.8
49.3
19.4
5.9
69.6
24 6
21.8
11.4
240
5.6
4.2
25.0
7.1
4.8
32.4
12.7
5.8
54.3
21.8
18.5
15.1
300
4.4
3.1
29.6
5.5
4.2
23.6
20.7
9.5
54.1
20.7
18.4
11.1
360
8.2
5.1
37.8
9.9
6.0
39.4
17.6
7.6
56.8
20.3
17.2
15.3
420
6.2
4.5
27.4
9.0
6.5
27.8
16.5
8.9
46.1
24.2
(27.3)

Declining Flow-rate
- 	 ' 1
Type HI
Filter No. 3
180
5.2
3.5
32.7
7.5
3.5
53.3
20.1
5.8
71.1
24.9
20.7
16.9
240
5.6
4.0
28.6
7.1
4.1
42.3
12.7
5.7
55.1
21.8
18.2
16.5
300
4.4
2.8
36.4
5.5
3.7
32.7
20.7
9.6
53.6
20.7
17.1
17.4
360
8.2
4.9
40.2
9.7
6.3
35.1
17.5
6.7
61.7
20.4
16.5
19.1
420
6.2
4.1
33.9
9.0
6.4
28.9
16.5
9.2
44.2
24.2
23.7
2.1
Declining Flow-rate
-p.
o

-------
Table 3.9  Media Size and  Depth for Up-flow  Filter
^"^^^^ Size and depth
Items -\^^
Filter media (Silica sand)
Sand for media support
Gravel for media support
Media size
Effective size
(mm)
1.16
2.11
Uniformity
coefficient
1.33
1.31
2~ 3
10-15
20-30
Depth (mm)
1,550
300
250
100
                        -  141  -

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Table 3.10  Operational Data of Filtration Run Length of
           Both Dp-flow Filter and Down Flow Filter
                                                              (his.)

Types of
Experiment
Up-flow Filter

Down-flow Filter
(Type II)

Filter
Filter
No. 4

Filter
No. 2

Items
Max.
Min.
Ave.
Max.
Min.
Ave.
Flow-rate (m3/m2-d)
180
131.00
54.25
91.45
125.25
11.25
71.55
240
105.00
20.50
68.80
101.50
7.50
53.17
300
124.45
20.00
55.90
125.25
21.75
48.07
360
55.50
23.50
48.50
65.75
4.50
38.80
                         - 142  -

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Table 3.11  Comparison of Filtrate Quality of Both Dp-Flow Filter and Down-Flow Filter
^^JTyr^offilter^
\ \ Filter nui
Xlnitial 	 	
Turbidity
Sus. solids
BOD
CODMn
Cone.
(mg/fi)
Tiber
m'-d)
Inf.
Eff.
Removal (%)
Cone.
(mg/fi)
Inf.
Eff.
Removal (%)
Cone.
(mg/fi)
Inf.
Eff.
Removal (%)
Cone.
(mg/fi)
Enf.
Eff.
Removal (%)
Up-flow filter
No. 4
180
8.0
3.4
57.5
13.0
4.0
69.2
22.8
6.8
70.2
16.7
15.3
8.4
240
6.1
3.4
44.3
11.4
4.0
64.9
17.8
5.7
70.0
14.5
12.9
11.0
300
6.9
3.2
53.6
12.2
5.0
59.0
23.4
6.8
70.9
16.0
13.1
18.1
360
8.3
3.1
62.7
13.0
4.6
64.6
21.4
6.8
31.8
14.0
12.7
9.3
Down-flow filter (Controlled)
No. 2
180
8.0
3.7
53.8
12.9
5.2
59.7
22.9
6.9
69.9
17.3
14.5
16.2
240
6.5
2.8
56.9
12.5
3.2
74.4
17.9
5.3
70.4
15.0
12.1
19.3
300
6.9
2.9
60.0 '
12.0
4.4
63.3
21.8
6.0
72.5
15.7
12.1
22.9
360
8.4
3.2
64.4
14.0
3.7
73.5
25.3
7.6
70.0
16.2
13.0
19.8
420
8.1
5.3
34.6
12.7
6.0
52.8
17.1
7.4
56.7
15.3
12.9
15.7
                                   -  143

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                                  Coagulant Tank
Final Sedimentation Tank
     Down Flow Type Gravity Filter
                                                         Filter No.l


r
Filter N
V
h
Media .

i
I
i .

.t
                                                                                            Filter No.3
                                                                                         Media
 Filtered Water
 Line No.l
  Rutz
PJPump
                                                                  Flow Measuring
                                                                  Tank No.2
                                                                                                                Surge Tank
                                                        Upflow Filter
                                                                                                                Grid
                                                                                                                     Media
FEtered
Water
Line
No.3
                                           Flow Measuring
                                           Tank No.4
                                                                                                                                   ~rr\ Debubbler
                                                                                                                                           Washed Water
                                                                                                                                           Flow Measuring Tank
                                                                                                   Outflow line
                                                                                                      	to-
                                                     Filtered Water Storage Tank
                                                                                                                               -tx-
                                                                                                                                              Effluent
                                                            -- Effluent
                                                 Fig. 3.1   Flow Chart of Pilot Filtration Facility, Kyoto Pilot Plant

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3 -
      6-
      5-
    V 4-
                   A
                    •
                    X
Filtration Flow-rate Variation of Type IV
Filtration Flow-rate Variation of Type III
Total Head Loss Variation of Type IV
Total Head Loss Variation of Type III
Turbidity of Influent
Turbidity of Effluent (Type IV)
Turbidity of Effluent (Type III)
                 Type IV •   See Table 3.5 and 3.6
                 Type III:   See Table 3.1 and 3.2
 1 -
                                                       32   36    40    44    48     52    56
                                                                          Run Length (hrs)
                                                                     60
                                                                            64
                                                                                 68    72
                                                                                             76
                                                                                                   80    84
-i
92
              Fig. 3.2   Effect of Media Size in Down-flow Declining Dual Media Filter on Total Head Loss, Flow Rate, and
                        Turbidity Variations
                         (Initial  Filtration Flow-rate   180m3/m2  d)

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1 -
0 J
      6 -
    -34 -
                  •
                  X
Filtration Flow-rate Variation of Type IV
Filtration Flow-rate Variation of Type III
Total Head Loss Variation of Type IV
Total Head Loss Variation of Type III
Turbidity of Influent
Turbidity of Effluent (Type IV)
Turbidity of Effluent (Type III)
                                                                                             Type IV : See Table 3.5 and 3.6
                                                                                             Type III: See Table 3.1 and 3.2
                          12   16    20    24   28     32   36     40   44

                                                          Run-Length (hrs)
                                                      48
                                                            52    56
                                                                        60
                                                                              64    68
                                                                                          72
   Fig. 3.3   Effect of Media Size in Down-flow Declining Dual  Media  Filter on Total  Head  Loss,  Flow  Rate, and
             Turbidity Variations
             (Initial Filtration Flow-rate  420 m3 /m2 •  d)
                                                                                                                           -7
                                                                                                                            6
                                                                                                                           -5
                                                                                                                           - 4  .0
                                                                                                                                ^

                                                                                                                           •3

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       6-1
        5-
	Constant Filtration Flow-rate
	Declining Filtration Flow-rate Variation
	 Constant Filtration Total Head Loss Variation
•	• Declining Filtration Total Head Loss Variation
   •A   Turbidity of Influent
   •   Turbidity of Effluent (Constant Filtration)
   X   Turbidity of Effluent (Declining Filtration)
X
13
                            12
                                  16   20
                         24    28
                                                         32
                                                                36
                                                                                                          64
                                                                                                                      72
                                                      40    44   48     52    56   60
                                                       Run Length (hrs)
Fig.  3.4   Comparison  of Constant Flow-rate and Declining Flow-rate Filtrations on Total Head Loss, Flow-rate,
           and Turbidity Variations in Down-flow Dual Media  Filters
           (Initial Filtration Flow-rate   180 m3/rn2- d)
                                                                                                                            76    80    84    88    92
                                                                                                                                         •9

                                                                                                                                         •8

                                                                                                                                          7

                                                                                                                                          6

                                                                                                                                          5

                                                                                                                                         • 4  £•

                                                                                                                                                          3  H

                                                                                                                                                          2

                                                                                                                                                          1

                                                                                                                                                          0

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-pi
CO
                  3-
                        6 -
                         s  •
                        4 -
     	Constant Filtration Flow-rate
     	Declining Filtration Flow-rate Variation
     	  Constant Filtration Total Head Loss Variation
     •	•  Declining Filtration Total Head Loss Variation
       ^    Turbidity of Influent
       •    Turbidity of Effluent (Constant Filtration)
       X    Turbidity of Hffluent (Declining Filtration)
                                                                                                       ,*_ 	 	  	 	 	
                       53
                      _o
                      LL.
                         1-
                  0J
                                           —p-
                                            12
              16    20
                          24
28
32
36    40    44
Run Length (hrs)
                                                                48
                                     52
                                     56     60    64    68    72
76
                           Fig.  3.5
Comparison of Constant  Flow-rate and Declining Flow-rate  Filtrations  on Total Head Loss, Flow-rate,
and Turbidity Variations in  Down-flow Dual Media  Filters
(Initial Filtration Flow-rate   420 m3 /m2 • d)

                                                                                                                     3

                                                                                                                     2

                                                                                                                     1

                                                                                                                     0

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3-
      6-
      5 -
    E 4-
                 Flow-rate Pattern of Variable Filter
                 Flow-rate Variation of Declining Filter
                 Total Head  Loss Variation of Variable Filter
                 Total Head  Loss Variation of Declining Filter
                 Turbidity of Influent
                 Turbidity of Effluent (Variable Filter)
                 Turbidity of Effluent (Declining Filter)
                                                                                                                                                   6


                                                                                                                                                   5
                                                                                                                                                      O1
                                                                                                                                                      ~o£
                                                                                                                                                   4  £



                                                                                                                                                      H
                                                                                                                                                  L0
                         12
                               16   20    24    28    32
                                              36    40    44    48    52    56    60     64   68    72    76    80   84
                                                 Run  Length (hrs)
Fig.  3.6  Comparison of Variable Flow-rate and Declining Flow-rate on Flow-rate, Total Head  Loss and Turbidity
          Variations in Down-flow Dual Media  Filters
          Average Flow-rate of Variable Filter:  Approx. 180m3/m2- d
           Initial Flow-rate of Declining Filter:   180 m3/m2- d
                                                                                                                                        88

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en
o
                                                                                                      Flow-rate Pattern of Variable Filter
                                                                                                      Flow-rate Variation of Declining Filter
                                                                                                      Total Head Loss Variation of Variable Filter
                                                                                                      Total Head Loss Variation of Declining Filter
                                                                                                      Turbidity of Influent
                                                                                                      Turbidity of Effluent (Variable Filter)/
                                                                                                      Turbidity of Effluent (Declining  / ,-'   \
             H 1 -
                      1 .
               0J
                                              16
                                                   20    24
                                                                     32    36
                                                                                 40   44
                                                                                           —i—
                                                                                            48
                                                                                                  52
                                                                                                        56    60   64    68    72
76   80
          —i—
           84
                                                                                     Run Length (hrs)
                                Fig. 3.7   Comparison of Variable Flow-rate and Declining Flow-rate on Flow-rate, Total Head Loss and Turbidity
                                          Variations in Down-flow Dual Media Filters
                                          f Average Flow-rate of Variable Filter:  Approx. 240 m3 /m2 •  d 1
                                          [initial Flow-rate of Declining Filter:   240 m3/m2 •  d         \
92
                             12

                             11

                             10

                            -9

                            -8

                            -7

                            -6



                            -4

                            •3

                             2

                             1

                             0

-------
3H   6-1
      5 •
     E4 -
     o
     o
Plow-rate Pattern of Variable Filter
Flow-rate Variation of Declining Filter
Total Head Loss Variation of Variable Filter
Total Head Loss Variation of Declining Filter
Turbidity of Influent
Turbidity of Effluent (Variable Filter)
Turbidity of Effluent (Declining Filter)
                               16    20    24    28
                                                      —i—
                                                       32
                            36    40    44

                            Run Length (hrs)
                                             48    52
                                                          56    60
                                                                     64
                                                                                 12
Fig.  3.8  Comparison of Variable Flow-rate and Declining Flow-rate on Flow-rate, Total Head Loss and Turbidity
          Variations in Down-flow Dual Media Filters
          T Average Flow-rate of Variable Filter:   Approx. 300 m3/m2 • d
          [initial Flow-rate of Declining Filter:   300 m3/m2 • d
                                                                                                                        • 3

                                                                                                                         2

                                                                                                                         1

                                                                                                                         0

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On
INJ
                            0J
                                                       How-rate Pattern of Variable Filter
                                                       Flow-rate Variation of Declining Filter
                                                       Total Head Loss Variation of Variable Filter
                                                       Total Head Loss Variation of Declining  Filter
                                                       Turbidity of Influent
                                                       Turbidity of Effluent (Variable Filter)
                                                       Turbidity of Effluent (Declining Filter)
                                                                                  32   36    40

                                                                                     Run Length (his)
                                                                                                   44
                                                                                                         48
                                                                                                               52    56    60    64    68   72
                                                                                                                                                 76
                               Fig.  3.9  Comparison of Variable Flow-rate and Declining Flow-rate on Flow-rate, Total Head Loss and Turbidity
                                         Variations in  Down-flow Dual Media Filters
                                          [ Average Flow-rate of Variable Filter:  Approx. 360 m3/m2 -d
                                          [ Initial Flow-rate  of Declining Filter:   360 m3/m2 • d

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3-
     6 -
                                Flow-rate Pattern of Variable Filter
                                Flow-rate Variation of Declining Filter
                                Total Head Loss Variation of Variable Filter
                                Tola] Head Loss Variation of Declining Filter
                                                                                    <*    Turbidity of Influent
                                                                                    •    Turbidity of Effluent (Variable Filter)
                                                                                    x    Turbidity of Effluent (Declining Filter)
                              16
                                    20    24
                                                                      44
                                                                            48
                                                                                  52    56
                                                                                                   64   68
                                            8    32   36    40
                                                 Run Length (lirs)

Fig.  3.10   Comparison of Variable Flow-rate and Declining Flow-rate on  Flow-rate, Total Head Loss and Turbidity
            Variations in Down-flow Dual  Media  Filters

            ^Average Flow-rate of Variable Filter:  Approx. 420 m3/m2 • d
            [initial Flow-rate of Declining Filter:   420 m3/m2 • d

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Cn
               1-
              0J
                                                                           40    44   48



                                                                            Run Length (hrs)



                                                  Fig. 3.11   Examples of Normal Operations of Dp-flow Filters
84   88
           92

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3 •
      6-
      5 -
   •04
   1=
     •3-
                                                                                                                 	  Total Head  Loss
                                                                                                                 	Filtration Flow-rate
      \ -
0    Initial Flow-rate  180m3/m2-d
©    Initial Flow-rate  240m3/m2-d
(3)    Initial Flow-rate  300m3/m2-d
0    Initial Flow-rate  360m3/m2-d
                                                                                                                                              ©
                         12    16    20    24    28   32     36   40    44   48    52    56    60     64   68    72   76    80    84

                                                                           Run Length (hrs)

                        Fig. 3.12  Examples of Suspended  Solids Leakage in Sand Beds at Up-flaw Filter Test  Operations
                                                     92
                                                           96

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              CHAPTER 4.  METAL SALTS PRECIPITATION
4.1    Estimate of Concentration of Dissolved Phosphorus in Effluent and
      Removal of Dissolved Phosphorus	157
  4.1.1   Form of Phosphorus Used for Determination of Mole Ratio	157
  4.1.2   Relationship between Mole Ratio, Dissolved Phosphorus in Effluent,
         and Residual Dissolved Phosphorus	157
  4.1.3   Summary   	160
4.2    Comparison of Coagulant Constant Feed and Mole Ratio Control	161
  4.2.1   Where Influent Flow is Set Constant	     	161
  4.2.2   Where Influent Flow is Changeable	162
  4.2.3   Considerations	164
4.3    Results of Pilot Plant Examinations	166
  4.3.1   Results of Wastewater Treatment	166
  4.3.2   Results of Sludge Dewatering	     .   ...       	167
4.4    Development of High-Rate Flocculation-Sedimentation System —
      An Example of Advanced Waste Treatment Technical Development
      at a Private Company —      .   .     	169
  4.4.1   Principles and  Features of the Installation           	169
  4.4.2   Pilot Plant Experiment at the Senda Sewage Treatment
         Plant, Hiroshima City	170
  4.4.3   Pilot Plant Experiment at the Shinhama Sewage Treatment
         Plant, Fukuyama City	         .       	
                                 - 156  -

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4.   METAL SALTS PRECIPITATIQN
4.1  ESTIMATE  OF  CONCENTRATION OF  DISSOLVED  PHOSPHORUS  IN
     EFFLUENT AND REMOVAL OF DISSOLVED PHOSPHORUS
     The Joint  Working Group on Advanced Wastewater Treatment Technology
conducted jar  tests in the  winter of  1974 on the phosphorus removal  by metal
salts precipitation. The  coagulants used  were  alum  (A12(SO4)3 • 18H2O), ferric
chloride (FeCl3, 26.2% Fe solution), and  MICS  (a mixture of alum and ferric sul-
fate, solution of  A12O3 (5.42%) and  Fe2O3  (2.0%) available on market here in
Japan.
     The samples  were influent to the primary settler and the secondary effluent,
taken around 9:00 a.m. from  14 to 15 typical  sewage treatment plants  in Japan.
4.1.1  FORM  OF  PHOSPHORUS USED FOR DETERMINATION  OF  MOLE
       RATIO
     In the  test the mole ratios of metal salts to be dosed were set at 0.5,  1.0,
 1.5, 2.0, 2.5 and  3.0 with the  phosphorus  (P:  total phosphorous by persulfate
digestion) in influent  as a  basis (e.g., Al/P, Fe/P, (Al +Fe)/P). No  particular pH
control was  carried out.
     Fig. 4.1 shows the relationship between  phosphorus  in influent and residual
dissolved phosphorus  (P-D, filtered through 1.2 n millipore, persulfate digestion)
for mole ratios of  1.0, 2.0,  and 3.0  based  on phosphorus in influent. Fig. 4.2
shows  the relationship between the dissolved  phosphorus  in influent and residual
dissolved phosphorus  for mole ratios of 1.0, 2.0, and 3.0 based  on dissolved phos-
phorus in influent.  Fig. 4.2 provides better correlation than  Fig. 4.1  when com-
pard on the  same  mole ratio.
     It is hence inferred that insoluble phosphorus in influent  does not react upon
Al dosed.
     Figs 4.1 and 4.2  show only the results of alum treatment, but the results of
treatments with ferric  chloride and MICS also  showed  the same tendency.
     For this reason,  the discussions hereunder use the mole ratios based  on the
dissolved phosphorus in influent.
4.1.2   RELATIONSHIP BETWEEN MOLE RATIO, DISSOLVED PHOSPHORUS
       IN INFLUENT, AND RESIDUAL DISSOLVED PHOSPHORUS
     As shown in Fig. 4.2,  the concentration  of dissolved phosphorus in influent
and residual dissolved  phosphorus are  expressed  by a straight regression line when
the mole ratio obtained based on dissolved phosphorus concentration of influent
is fixed at a  constant value.
     It is assumed that the  relationship between the concentration of influent dis-
solved  phosphorus (P-Dj ) and the concentration of effluent dissolved phosphorus
(P—D£) is given by the following  formula.
         (P-DE) = ax(P-Dt) + b  	(1)
                Mole ratio: constant
                (P-DE), (P-Dj): inmg.P/lit.
                a, b:  constants
     Then regression  line  is  determined  for each  mole ratio, and a,  b,  and
                                     157

-------
standard deviation of (P-D£) is calculated as shown in Table 4.1.
     While the calculation for influent to the primary settler is made up to a mole
ratio of 4, the calculation for the  secondary effluent is up to  a mole ratio of 3.
This is due to the following reason.
     In this test, with the concentration of phosphorus in the influent as a basis
for determination of mole  ratio, the mole ratios were  increased up to  3 at an
interval of 0.5.  But  it  was  found that the mole ratio can better be determined
based  on  the concentration of dissolved  phosphorus  as stated in 1—2,  and the
results of the test were revised with the mole ratios determined according to the
concentration of dissolved phosphorus.
     On  the  other hand, the  ratio  of insoluble phosphorus in influent to phos-
phorus was larger in  the influent to  the primary settler; almost all results  showed
that when the mole ratio was 3.0 as calculated based on phosphorus in influent to
the primary  settler,  the mole ratio calculated on the bais of dissolved phosphorus
became more than 4.0.
     In the case of secondary effluent, the ratio of insoluble phosphorus was com-
paratively  small, so  there  was rarely the case  that  the mole ratio  based  on  dis-
solved  phosphorus was beyond  3.5. This is  also evidenced by the fact that the
secondary effluent show better correlations in Fig. 4.1.
     The  range  of the concentration of dissolved phosphorus in the inlfuent used
in the experiment was  almost the same for ferric  chloride, MICS and alum. Thus
the range  of the  concentration of dissolved phosphorus in influent in which the
computation results  shown  in Talbe 4.1  can be applied seems to be preferably 1.5
to  10  mg.P/lit.  for influent  to the primary settler and 0.5  to  3  mg.P/lit.  for the
secondary effluent.  From  Eq. (1),  the  removal of dissolved phosphorus  (Rp_D)
for the same mole ratio can be expressed as follows.

          (RP_D)(%)   =  (1  -((p  "  ffix  100

                        =  (l-a	)x  100  	(2)
                                 (P-D,)'
     Eq.  (2) suggests that  the mole ratio  calculated from dissolved phosphorus in
influent does not univocally determine the removal (RD  „  ). but that  in the same
                                                   K — U
mole ratio the  removal increases with increase in the  concentration of dissolved
phosphorus in influent as b is larger than O (see Table  1).
     By way of example, Fig. 4.3  shows the relationship between the removal of
dissolved  phosphorus and the  concentration of dissolved phosphorus with respect
to the case where the influent to the primary settler is  treated  with alum.
     In order to compare the performance of three coagulants, the concentrations
of dissolved  phosphorus in  the effluent of influent to  the  primary settler treated
with each coagulant  were determined with a, and b in Table 4.1. The values used
for the calculation are  as follows. The mole ratios  are 0.5, 1,  1.5, 2, 2.5, 3,  3.5,
and  4.0,  and the concentration of dissolved phosphorus in influent to the  primary
settler are 2, 4,  6, and 8 mg.P/lit. The results were as follows.
     The  concentrations  of  dissolved  phosphorus after  treatment  with  ferric
chloride and  MICS were respectively 1.61 times  (0.94 to  9.41) and 1.05 times
                                    - 158 -

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(0.57—3.85)  on the average as large as that after treatment with alum; namely,
ferric chloride was inferior in removal of phosphorus to the other two.
     One of  the causes conceivable is pH after addition  of coagulant. As already
touched upon, the experiment under discussion was conducted without pH adjust-
meht. As a consequence,  as against the average pH value of raw sewage  being 7.4
(6.6-8.1), the pH value after treatment with a mole ratio of 3, for example, was
6.8 on the average  for  all three coagulants — alum  6.8  (6.3~7.3), ferric chloride
6.8 (6.5-7.2) and MICS  6.8 (6.3-7.4).  It is said that the optimum pH value for
removal of phosphorus is  5.5 to 6.5 for alum and 4.5 to  5.0 for ferric chloride*.
     The deviation of the average pH value, 6.8, from the optimum pH value after
treatment at  a  mole ratio of 3  was 1.8  to 2.3 for ferric chloride and 0.3 to 1.3
for alum, and was greater in ferric chloride treatment than in alum treatment. It is
therefore  considered  that the  treatment  with alum  will lower residual  dissolved
phosphorus concentration more than with ferric  chloride. The same tendency was
observed with the secondary effluent.
     With the values in Table  4.1 taken  as a reference, the relationship between
the more ratio  and dissolved phosphorus concentration obtained  after treatment
of raw  sewage with alum is shown in Fig.  4.4. According to  Fig.  4.4  , the dif-
ference  of the  dissolved  phosphorus concentration  after treatment due to dif-
ference  in  the dissolved phosphorus concentrattion in influent decreases with  in-
crease in  mole ratio, attains zero  at a certain mole ratio (2.5 in this case), and
then turns reversely.
     The mole ratio  at which  the  dissolved phosphorus in the effluent  was held
constnat irrespective of the concentration of dissolved phosphorus in the influent
to the primary settler was 2.5 for alum,  3.4 for ferric chloride and 2.9 for MICS.
     The same tendency was observed with the secondary effluent.
     The  removability  of dissolved  phosphorus in  raw  sewage  and  secondary
effluent is  compared  in the following way. Dissolved  phosphorus concentration in
influent was  taken  as 2 and 3  mg./lit. which lie in  the  range in which Table 4.1
can be applied common to influent to the primary settler and secondary effluent,
and  as  0.5,  1, 1.5, 2,  2.5 and 3 in terms of mole ratio, and  the corresponding
residual  total dissolved  phosphorus  concentrations  were calculated.  Then the
calculation showed  that   the  ratios  of  dissolved phosphorus  in  the  secondary
effluent to that  in the raw sewage treated  with alum,  ferric chloride and MICS
were  1.25  (1.06-1.50),  1.01  (0.78-1.16) and  1.06 (0.94-1.21) on the average
respectively.  From this, it is inferred that  the secondary effluent is a little easier to
remove phosphorus as compared with raw  sewage, a little though the difference may
be.
     The relationship between  a and b  in Table 1   and mole ratios is  shown in
Fig.s 4.5 and 4.6 with respect to the treatment of raw sewage with alum.
     In  other conditions, reltionships between a and b in Table 4.1  and  mole
ratios are similar to Fig. 4.5, and 4.6.
     If a and b  can be expressed by the following formula (Eq.  3) according to

* U.S.E.P.A.  Process Design Manual for Phosphorus Removal, Oct. 1971.
                                      159

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Figs.  4.5  and  4.6,  then the  substitution of Eq.  (3) for Eqs.  (1)  and (2) will
establish functions in terms  of the mole ratio to phosphorus of dosed metal salts
obtained based  on the dissolved phosphorus concentration in influent as also of
dissolved phosphorus concentration in  influent, which can show residual dissolved
phosphorus concentration and removal of dissolved phosphorus in the metal salts
precipitation.
         a = f(MR), b - g(MR)   	(3)
              MR is mole ratio based on dissolved phosphorus in influent.
     This  time,  however, we are not yet to refine the curves in Figs. 5 and 6 into
such a function, and we will continue further study in this respect.
     Tables 4.2, and 4.3  show  the relationships between the dosages of alum, ferric
chloride, and  MICS and mole  ratios  necessary  for attaining the target dissolved
phosphorus concentrations in  effluent of 0.1, 0.2, 0.3,  0.5, and 1.0 mg.P/1, and
the target  removal of dissolved phosphorus of 98,  95, 90, 85,  and 80%, and dis-
solved phosphorus in influent.

4.1.3  SUMMARY
i)    In case wastewater  is treated with metal salts, like aluminum salts,  and iron
     salts,  to  remove  phosphorus, these metal  salts react upon dissolved  phos-
     phorus, but not upon insoluble phosphorus.
ii)   When the  mole ratio, Al/, Fe/P,  or (Al + Fe)/P, calculated  based  on dis-
     solved phosphorus  concentration  in  influent is  set  constant,  there  is a
     rectilinear  relationship  between  the dissolved phosphorus  concentration in
     influent and that in the effluent.
iii)  The  concentration  of dissolved  phosphorus  in influent  to  which the  co-
     efficient shown in Table 4.1 prepared for determing the concentration  of dis-
     solved phosphorus in  effluent and  mole ratio  based  on the concentration of
     dissolved phosphorus  in  influent  can be applied should preferably be  in the
     range  of  1.5 to  10  mg.P/lit. for influent to the primary settler and 0.5 to 3
     mg.P/lit. for secondary effluent.
iv)  Even  if the mole ratio  is set constant, the removal  of dissolved phosphorus
     increases  with increase  in the  concentration  of  dissolved  phosphorus in
     influent.
v)   The difference of the concentration of dissolved phosphorus  after treatment
     due to difference  in  the concentration  of dissolved phosphorus in influent
     decreases  with increase in mole  ratio,  is reduced  to zero at  a  certain mole
     ratio,  and  then turns up from there on.
vi)  So far as  the removability of phosphorus  is  concerned, alum and MICS lie
     almost on  the same level, while ferric  chloride  is  poorer than  them.  In the
     experiment using these three metal salts, pH control was not carried out.
vii)  Removal  of dissolved  phosphorus  is a little better in secondary  effluent than
     in raw sewage, though the difference is not  so  large.
viii)  The results obtained in the experiment concerning the relationship betweeen
     target removal  of dissolved phosphorus and  coagulant  dosage are shown in
     Tables 4.2  and 4.3.
                                     160

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4.2  COMPARISON  OF  COAGULANT CONSTANT FEED AND MOLE RATIO
     CONTROL
     It is clarified  under  item  4.1 that in the phosphorus removal by metal salts
precipitation, the dissolved phosphorus concentration in effluent is dependent on
the mole ratio of dosed metal salts to dissolved phosphorus in influent as well as
on the concentration of dissolved phosphorus in influent.
     In sewage  treatment plant, usually, the influent flow and the dissolved phos-
phorus concentration in influent  are changeable.
     In order to  minimize the loading of dissolved phosphorus in effluent mole
ratio  control method in  which the metal salts dosage  is controlled to make the
mole  ratio  constant  and  constant feed method  in  which metal  salts are fed at  a
constant rate were put to comparison study with reference to the same coagulant
and the same total dosage.
     To this purpose, experiments were carried out  in the following way.
     "A" sewage  treatment plant in the suburbs of Tokyo covering a population
of 11,300 with a separate  sewer system and  undertaking  secondary treatment in
step  aeration process with two  hours of aeration time, was picked up.
     An automatic sampler was used to take its secondary effluent every hour for
24 hours in order to  obtain influent for the experiment, and 24 influents  were
analyzed of  dissolved phosphorus.
     In the constant  feed method, alum was dosed  to make Al/P mole ratios of 1,
2 and 3 with respect to  the mean value of the concentration of dissolved  phos-
phorus in influents.  In the mole ratio control method,  alum was dosed so that
Al/P mole ratio could  be  1, 2 and 3 with respect to dissolved phosphorus in  each
influent. The samples added with alum (24 x 2 x3 = 144 test tubes) were put to
jar test, and  total dissolved phosphorus (H2 SO4  digestion) was analyzed  each.

4.2.1  WHERE INFLUENT FLOW IS SET CONSTANT
     Fig. 4.7 shows  time-dependnet  changes  of inlfuent flow rate and the con-
centration of dissolved  phosphorus in both influent  and  effluent.
     Fig.  4.8 refers to  constant feed method  and mole ratio control method, and
shows their  relationships between the concentration of  dissolved phsophorus in
influent and the removal of dissolved phosphorus.  The  concentration of dissolved
phosphorus  in  influent recorded a  maximum  value of 6.73 mg.P/lit. at  noon,
a minimum  1.73  mg.P/lit. at 7 a.m.  and  3.36 mg.P/lit. on the average. The  ratio
of the maximum  to  the  minimum was  3.9. In the constant feed method, the
maximum to minimum ratio of dissolved  phosphorus  in effluent was 7.5,  14.9
and  17.5 for the mole ratios of 1, 2, and 3, respectively, while in the  mole  ratio
control method, the  corresponding maximum to minimum ratio was 3.1, 2.8 and
4.4.  At any mole ratio,  the mole ratio  control method could  make smaller the
change in  the concentration of dissolved phosphorus in effluent  than the constant
feed  method.
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     From  Fig. 4.8, it is found that in the constant feed method, the removal of
dissolved phosphorus  decreased  with increase in the concentration of dissolved
phosphorus in influent.
     This is because as alum dosage was constant, the mole ratio (Al/P) decreased
with  increse  in  the  dissolved  phosphorus concentration  in influent. For this
reason, the lower the  dissolved  phosphorus concentration  in  influent,  the smaller
the residual total  phosphorus  concentration, sending up the maximum to mini-
mum ratio  of dissolved phosphorus in effluent. On the other  hand, the mole ratio
control  method increased  the  removal of dissolved  phosphorus with increase in
the concentration  of  total dissolved  phosphorus in influent just as the tendency
discussed under item  4.1; namely, the maximum to minimum ratio  of dissolved
phosphorus in effluent did not  become so large.
     Assuming that the influent flows were equal to the average flow rate of "A"
sewage plant at that sampling day  (87 m3 /hr),  the  dissolved phosphorus loadings
of influent and  effluent, average removal and concentration are as shown in Table
4.4.
     According to  Table  4.4, the mole ratio control can reduce dissolved phos-
phorus in the effluent irrespective of mole ratios as compared with the constant
feed method.  At mole ratios of  1, 2, and 3, the dissolved phosphorus loading in
the effluent  in  the  mole ratio  control method  was 91%,  86% and  81%  of the
corresponding values achievable by the constant  feed method.
     Fig. 4.9  shows the relationship  between the dissolved phosphorus concentra-
tion in  influent and the  difference  in dissolved  phosphorus  concentration  after
treatment  between in the constant  feed method and in  the mole  ratio control
method.  According to Fig. 4.9, it is found that a turn of tendency is seen at an
average dissolved phosphorus concentration of 3.36 mg.P/lit.
     Assuming that these  two  demarcated  ranges  can  each be replaced  with  a
straight  line,  respective regression straight lines  can be determined as shown in
Table 4.5.
     It is found from  Table 4.5 that irrespective of whether  the mole ratio is 1, 2
or 3, the  slope (a) is larger in the  case  where the average  dissolved phosphorus
concentration in influent  is larger than 3.36 mg.P/lit. as compared with the case
where the average concentration is lower.
     This difference in slopes means that the constant feed  control  increases the
solved phosphorus in the constant feed method decreases with increase in the con-
centration  of dissolved phosphorus  in  influent whereas  the mole ratio  control
increases it to the contrary.
     This  difference is slope means  that the constant feed  control increases the
dissolved phosphorus loading in the  effluent than the mole ratio control method.

4.2.2  WHERE INFLUENT FLOW IS CHANGEABLE
     The constant feed in  the  case of influent flow  change  assumed a method of
keeping the coagulant  dose per unit volume of influent at a constant value.
     In  the mole ratio control method, dosage was so made  as to be proportional
to the influent  flow rate  and the concentration of dissolved phosphorus in the
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influent in an attempt to keep the mole ratio (Al/P) always constant.
     Fig.  4.10  shows time-dependent changes of dissolved phosphorus loading in
the influent and effluent  which are determined by  multiplying the influent flow
rate  shown  in  Fig. 4.7 by the concentrations  in fluent  and  effluent of dissolved
phosphorus.
     In connection with  this, daily total laoding, removal,  average concentration
(quotient  obtained by dividing daily dissolved phosphorus loading in the effluent by
daily influent flow), and Al consumption are shown  in Table  4.6.
     According to  Table  4.6,  it  is found that dissolved phosphorus loading  is
lower in the mole ratio  control method than in constant  feed method.
     However,  the  mole ratio  control method consumes 6.7% more Al than the
constant feed  method.  This is  because the influent flow was comparatively large
when the concentration of dissolved phosphorus in influent was  higher than the
average.
     In order  to make comparison on a  same Al  consumption  basis,  the  mole
ratios for  the  mole ratio  control were taken as 1/1.067 = 0.94 and  in  the same
way,  1.87 and 2.81, and  the  corresponding loadings of dissolved phosphorus in
the effluent were determined from Fig.  4.11 and compared  with  the values listed
in Table 4.3 for the constant feed  method.
     In this case, at mole ratios of 1, 2 and 3 in the constant feed  method, the
mole ratio control  method reduced daily total loading of dissolved phosphorus in
effluent to 93%, 91% and  88%, respectively.
     Qualitatively  speaking, there  may  be the following effects of the way of
correspondence between the time  change of influent flow and  the time  change of
dissolved phosphorus in influent on the daily total loading of dissolved phosphorus
in the effluent.

i)   Where  the influent  flow  and  the  dissolved  phosphorus concentration in
     influent are proportional to each other:
     When the  constant feed method and mole ratio control  method  are practised
     on the same  mole ratio,  the  mole ratio control  method  even more reduces
     the dissolved  phosphorus loading in  the effluent, because when the con-
     centration of  dissolved phosphorus in influent is larger than the average in
     which the mole ratio  control  method  better removes  dissolved phosphorus
     than  the constant feed method, the flow rate is larger than the average.
     Al dosage, however,  becomes  larger in the mole  ratio control method  owing
     to the reason  explained above.
     Accordingly,  if the mole  ratio control is carried out on  the same Al con-
     sumption  with the constant  feed method, the mole ratio of the mole ratio
     control becomes smaller than referred to in the constant feed mehod.
     The  mole  ratio control method is agreeable in that the  dissolved phsophorus
     loading of  influent at a  point where the dissolved phosphorus removal be-
     comes larger than  in the constant feed method,  is  larger, but is disagreed in
     that  the mole ratio becomes smaller.
ii)   Where  the influent,   flow and  the  dissolved  phosphorus concentration in
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    influent are in inverse proportion to each other:
    This is quite contrary  to the tendency examined under item i) above. Name-
    ly, the mole ratio control  is disagreed in that the dissolved phosphorus load-
    ing in the influent at a point where the  removal becomes larger than the
    constant  feed mehtod becomes  smaller, but  is agreeable  in  that the  mole
    ratio becomes larger.

    To follow Case  (a),  9:00  flow  which was maximum  and 13:00 dissolved
phosphorus concentration  which  was also maximum were adjusted to have con-
curred, and calculations were made.
    To follow Case (b),  2:00 flow  which was minimum and 13:00 concentration
which  was maximum were adjusted  to  have  concurred, and  calculations were
made.  Fig.  4.12 shows the relationship between  the flow and  concentration of
dissolved phosphorus for respective cases.
    The computation results appear in Table 4.7.  Table 4.7 also shows a case of
constant flow  and another in which  flow and phosphorus concentration concurred
really.
    From Table  4.7, the comparison between the constant feed  and the mole
ratio control in which the coagulant dosages are the same in Al reveals that which
method is more advantageous than  the other is dependent on  (1)  mole ratio and
(2) way of  correspondence between  time changes of influent  flow and the dis-
solved  phosphorus concentration in influent.
    In case where the mole ratio is 1 as referred to in the constant feed, the way
of correspondence between flow and  concentration  makes  little difference, and
dissolved phosphorus  loading  after treatment  in mole ratio control is 91 to 94%
of that after  constant feed treatment. Similarly,  the mole ratio of 2  develops a
loading range of 86 to 91%.
    At the  mole ratios of 3  in the constant feed, the loading changes depending
on  the mode  of  correspondence between the flow and concentration; when the
flow tends to  become in reciprocal proportion  to  phosphorus  concentration, the
mole ratio control method becomes  more advantageous.

4.2.3   CONSIDERATIONS
    It  is  found that the  mole  ratio control method can reduce dissolved phos-
phorus  loading in  the effluent more than the  constant  feed method even when
compared  on the same basis of alum consumption. (See Table 4.7)
    It  should be noted however that this take "A" sewage treatment plant as a
model  and that the  method  presupposes  that  the  measurment  of flow and dis-
solved  phosphorus concentration in influent  is made continuously without time
delay.
    "A" sewage treatment plant is a separate sewer type sewage treatment plant
located in a Danchi (housing  complex) and is considered to  have very changeable
concentration  of dissolved phosphorus in the raw sewage, and secondary  effluent.
For example,  the Toba Sewage Treatment Plant in Kyoto (influent flow: approx.
4.20 million m3/d.) was found on a survey to have the phosphorus concentration
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in the secondary effluent changed in 24 hrs from a maximum of 2.12 mg.P/lit. to
a minimum of  1.76 mg.P/lit., with the maximum to minimum ratio at 1.20. If the
metal salts precipitation is applied to this less changeable sewage for removal of
phosphorus, the mole ratio control will  not  be  able to exhibit  the effects shown
in this experiment.
     The measurement of influent flow  will be accomplished easily in real time if
a suitable instrument is applied.
     Even with the colorimetric analysis method which is the most  promising at
present,  the  measurement of the concentration of dissolved phosphorus in the
influent will unavoidably take a time lag of 20 to 60 min.
     The  applicability of  the  mole  ratio control method  should  therefore  be
judged after  due consideration of not only  the results of jar  test, but also con-
siderations time-dependent pattern of influent dissolved phosphorus concentration
and  influent  flow, as well as response  characteristics of phosphorus analyzer avail-
able.
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4.3  RESULTS OF PILOT PLANT EXPERIMENTS
     The Yokosuka Advanced Wastewater Treatment Pilot Plant has two systems of
precipitation; one using lime and the other using metal salts. Dealt with here are the
results of experiments on the precipitation using alum as coagulant in the metal salts
system and on the  filtration. The  operating conditions  of  alum precipitation and
filtration are shown in  Table 4.8. Both flow rate of the influent, which is secondary
effluent,  and alum dosage were kept constant throughout  the experiments.

4.3.1  RESULTS OF WASTEWATER TREATMENT
     Table 4.9 shows the average results of wastewater treatment.
a.    Removal of suspended solids
     Turbidity and suspended solids were removed about 30% by precipitation and
about 90% after filtration. With a view to improving the removal of suspended solids
in the sedimentation tank, the effects of dosage of ferric chloride and anionic poly-
mer as flocculation aids and of returning sludge were examined.
     The mean values of the  results are shown in Table  4.10,  According to Table
4.10, the concentration of suspended  solids in the effluent of the sedimentation
tank is found unaffected by a dose of 0 to 5.0 mg.Fe/1  of ferric chloride, a sludge
return ratio to  influent of 0 to 30%  and a dose of 0 to 0.5 mg/1 of polymer.
     The concentration of suspended solids was relatively constant within the range
of 10 to 15 mg/1,  independent on these test conditions. This will be clarified by
further investigations scheduled, including a test in which the overflow rate is to be
changed in the range of 10 to 100 m3 /m2 d and a test of a shallow settling device.
     The Yokosuka pilot Plant is equipped with two filters, different in constitution
of media. (See Table 4.11). The  media of the No.2 filter is coarser than that of No. 1
filter.
     The quality of the filter  effluent shown in Table 4.9 was obtained by analysis
of a composite sample consisted  of effuents from No. 1 and No. 2 filters.
     The filtration run  length at a total head loss of 2 m was 15.0 hrs and 18.5 hrs
on the average for No.  1 filter  and No.2 filter, respectively.  Namely, the filtration
run length of No.2 filter was  1.32 times as long as that of No. 1  filter. On the other
hand, the average concentration of suspended solids in filter effluent  was 1.0 mg/1
and  1.6 mg/1 for No. 1 filter and No. 2 filter, respectively, demonstrating that No.  1
filter, which used fine media, excelled No.2 filter.
b.    Removal of phosphorus
     Phosphorus and orthophosphate  were removed respectively 90.3% and 91.7%
after filtration. Their average concentrations in the  filter effluent were 0.173 mg.p/1
and 0.109 mg.P/1, respectively as shown in Table  4.9. The dissolved phosphorus in
effluent treated by metal salts can  be  estimated by the method discribed in Section
4.1 if the mole ratio of the dosed metal salts to phosphorus based on the dissolved
phosphorus concentration in  influent and the  dissolved phosphorus in influent are
known.
     In the period when the data shown  in Table  4.9 were collected, the dissolved
phosphorus was not analyzed. Therefore, the comparison  of estimated  and measured
concentrations in the  effluent  from sedimentation fank will be made using data
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shown in Table 4.10 and the values of coefficients listed in Table 4.1.
     The average concentration of the dissolved
     phosphorus in influent                                   1.411 mg.P/1
     Mole ratio (Al/P)                                       3.19
     Coeffecient a at mole ratio 3.19                          0
     Coeffecient b at mole ratio 3.19                          0.25
     Concentration of dissolved phosphorus in effluent (mg.P/1) = a-(concentration
of dissolved phosphorus in influent) + b = 0 x 3.19 + 0.25 = 0.25 (mg.P/1)
     One  the  other hand, the average  concentration  of dissolved phosphorus in
effluent shown in Table 4.10 is 0.130 or roughly 50% of 0.25  mg.P/1 of estimated
value.  The  results  of experiments  by  the Joint  Working Group  on Advanced
Wastewater  Treatmnet discussed  under Section 4.1 include data obtained  from the
Shitamachi  Sewage  Treatment  Plant,  Yokosuka,  where  the pilot  plant under
discussion is installed. Here, a similar result was obtained. Namely, when secondary
effluent is treated  by alum precipitation at mole ratio of 3, dissolved phosphorus in
the effluent is  estimated to be 0.279 mg.P/1, while the actual concentration was
about half the estimate or 0.142 mg.P/1 (concentration of dissolved phosphorus in
influent: 0.686 mg.P/1).  Thus it is inferred that  the dissolved phosphorus in  the
secondary effluent of the  Shitamachi Sewage  Treatment Plant  is easy to remove by
alum addition compared with effluents of other sewage treatment plants, and the
causes are to be studied.
     In  the  experimental  period during which the  data listed in Table  4.9 were
collected,  the average concentration of dissolved phosphorus in the in fluent of the
filter was 0.124 mg.P/1. On the other hand, phosphorus concentration in  effluents
from No.l filter and No.2 filter were 0.075 mg.P/1  and 0.091 mg.P/1, respectively.
Hence in  No.l filter, at  least 0.049 mg.P/1 or 40% of dissolved phosphorus was
removed, while in No.2 filter 0.033  mg.P/1 or 27% was removed.
c.    Removal of organic matter and bacteria
     As to removal of organic motter by alum precipitation and  filtration, removal
of BOD was the highest among BOD, COD by potassium permanganate, and COD by
potassium dichromate.   Removals  of COD by potassium dichromate and COD by
potassium permanganate  were almost  on the same level. The value of  COD by
potassium permanganate was about  one third that of COD by potassium dichromate.
     The common bacteria were removed only 38.7% before filtration, but coli-form
bacteria were removed as much as  90.6%, showing  that coli-form bacteria are easier
to remove than common bacteria.

4.3.2  RESULTS  OF SLUDGE  DEWATERING
     Alum sludge from an alum sedimentation  tank was thickened and dewatered by
means of a centrifuge. The centrifuge used for  the test was the smallest one available
on market for use in sewage sludge dewatering, having a standard sludge feed rate of
1  m3 /hr., and was modified for the  test purposes.
     The characteristics of feed  sludge,  test  conditions and  dewatering results are
shown in Table 4.12. According to Table 4.12,  it is found that alum sludge is hard to
dewater with a centrifuge without chemical dosage.
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     Even with  the result  of test No. 4 which was the best among the results, the
rate of total solids captured in dewatered sludge was 48.4%, and water content of
dewatered sludge was 88.2%. At that  time, the suspended solids in the centrate was
7,000 mg/1.
     Then, alternative dewatering  methods are called for, which may include: (1)
centrifugal dewatering with desage of polymer, (2)  dewatering after being mixed
with organic sludge, (3)  dewatering after freeze conditioning, and (4) use  of filter
press or vacuum  fieter.
     Preliminary study of freeze conditioning was carried out using a home freezer
to freeze the alum sludge. The settling test for the alum sluage showed that the ratio
of the sludge volume after 30 min. settling to the intial volume was 27% for the
freeze  conditioned sludge  as  against  95% for the  non-treated, evincing that the
thickening rate can be improved sharply by the freezing and melting process.  This
held also true with the lime  sludge.
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4.4  DEVELOPMENT  OF  HIGH-RATE  FLOCCULATION-SEDIMENTATION
     SYSTEM - AN EXAMPLE OF  ADVANCED WASTE TREATMENT TECH-
     NICAL  DEVELOPMENT  AT  A PRIVATE  COMPANY -
     In Japan, several types of chemical flocculation-sedimentation installation have
been introduced at water purification plants, etc. The chemical flocculation-sedi-
mentation system described here has been developed by a private company based on
a new  concept. This system has some advantages compared with conventional ones:
for example,  it can provide larger overflow rate, and floe becomes in a pellet state in
the sedimentation installation thereby, facilitating its treatment.
     Because this new installation  can remove the residual organic substances and
ortho-Phosphate in the secondary  effluent  with  a high  efficiency within a very
small site, many sewage  works engineers in  several cities have paid attention to it
with interest.
     This is a report on pilot plant studies in Hiroshima and Fukuyama Cities.
     This system will be assessed as an actual  facility by the  Japan Sewage Works
Agency's Committee of Technology Evaluations in  1976.
4.4.1  PRINCIPLES  AND FEATURES OF THE  INSTALLATION
     This system is a flocculation-sedimentation installation  of the sludge blanket
type in which both polymers and metal salts coagulants such as aluminum sulphate
and ferric chloride,  are used. Since floes forming the sludge blanket are huge pellets,
as big as 5 to 10 mm, the installation  has a good characteristic in terms of settling,
has fewer carry-overs of floes and can be designed to allow overflow rate of 300 m/d
or more.
     The mechanism  of formation of such huge pellets has not been fully under-
stood. But several experiments have proved that this installation is very effective to
remove colloidal organic matter and phosphate.
     The pilot scale experimental facility  used for the study is shown in Fig.  4.13.
Its major portion is composed of a  1.8m x 1.8m square flocculation-sedimentation
tank, a mixing tank which mix water and coagulants and tanks to dissolve coagulants.
     An  electromagnetic  flow  meter and an  inflow  control  valve are provided.
A predetermined quantity  of inflowing water is fed to the mixing tank  and mixed
with inorganic coagulant  (aluminum sulphate).  Polymer is fed with pressure to  the
piping between  the  mixing tank and the installation (flocculation-sedimentation
tank).  The influent is sent to the installation from its bottom. Water and floes  are
separated when  they  passethrough the sludge blanket zone consisting  of granular
floes. Then water is discharged from  the overflow weir. The separated floes gradually
grow by the coagulation action given by the inside impeller anto granular floes which
consists of the sludge blanket. The level of the sludge blanket which goes up gradual-
ly is detected by the ultrasonic sludge level sensor mounted a predetermined  hight.
And by the operation of the sludge drawing valve which is connected  electrically
with the sludge level sensor, the sludge blanket zone is maintained at  a fixed level.
     Originally, the installation was  designed to use a square tank. But later it was
found  that a square tank difficulties in  maintaining the sludge blanket  zone at a
fixed state at corners. Therefore, the installation was remodeled to  use a octagonal
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tank, in which the sludge blanket zone could be kept at a fixed state. In an actual
facility, it  is considered  that  circular  type  would be the best. In that case, the
maximum diameter will be 5.5 m considering the limit for the peripheral velocity of
impeller not to destroy the floe.

4.4.2   PILOT PLANT EXPERIMENT AT THE  SENDA SEWAGE TREATMENT
       PLANT,  HIROSHIMA CITY
    Experiments as  to use of this  high-rate flocculation-sedimentation  system as
a tertiary treatment facility of waste water was conducted from Feburary to April,
1970,  using  the  secondary  effluent  from the  Senda Sewage Treatment Plant,
Hiroshima  City,  The Plant is a medium-sized treatment plant having  a planned
serving population of 100,000 and adopting conventional activated sludge system.
i)   Water quality of influent
    Water quality of the secondary effluent (that is, influent to the high-rate floc-
    culation-sedimentation system) during the period of experiments was as shown
    in Table 4.13. Fig. 4.14 shows  protted relations between suspended  solids and
    total CODMn m secondary effluent. From this figure, one can find it is known
    that even though suspended solids are completely removed, about 4  to 5 mg/1
    of soluble CODMn still remains.
ii)  Time needed for accumulation of pellet-state  sludge in the starting of operation
    Operation was started under the following conditions:
    Quantity of flow, 50m3 /hr; overflow rate, 250mm/min; dosing rate of alum,
    50mg/l  and dosing  rate of polymer, l.Omg/1. Under these  conditions,  the
    time needed for the  blanket level to reach the predetermined height (i.e., 1.5m
    above the inflow port) was about 10 hours when treating low SS  secondary
    effluent like one shown in Table 4.13.
iii) Effects of the dosing rate of alum on flocculation
    Jar tests: Laboratory tests have been conducted with the secondary effluent
    containing 15mg/l  of suspended  solids and  13.2mg/l  of CODMn  to which  a
    various quantity of  alum was added. A good flocculation was observed when
    alum dosage was 40mg/l  as A12 (SO4)318H2O and flocculation was excellent
    when  dosage was 50mg/l.
    Continuous tests:   Effects of alum dosing rate on the quality of effluent were
    examined  under  thi conditions as follows: overflow  rate, 250mm/min;
    retention time in  buffled flocculator, 80 sec.; polymer dosing rate, lmg/1;
    and dosing  rate of alum, 50 to 60mg/l. Within the range of alum dosing rate
    examined, differences in performance were not so significant. But in order to
    form  core floes in  the sludge blanket, the  alum dosing rate must be 40 to
    50mg/l. If the rate is 30mg/l, the size of core floes is too small and the quality
    of effluent tends to be slightly worse.
iv) Optimum period between dosing of alum and dosing of polymer
    In  this experiment, overflow rate was set at  250mm/min, dosing rate of alum,
    at 50mg/l,  that of polymer,  at lmg/1, and mixing intensity in the  flocculation
    tank  at 0.62 (kg.f-m/nr'  sec). Under these conditions, the  optimum period
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     between dosing of alum and that of polymer was found to be 80 seconds or so.
v)   Maximum overflow rate for stable operation
     The  effect of overflow rate on the stability of the sludge blanket was studied
     under the  condition of 50mg/l of  alum dosing rate and  lmg/1 of that  of
     polymer As a result, it was found  that  the critical up flow velocity is in the
     vicinity  of 300mm/min If the installation is designed to  obtain more uniform
     distribution of velocity throughout the sludge blanket, overflow rate may  be
     increased up to about 350mm/min.
vi)  Thickening characteristic of excess flocculated-sedimented sludge
     Thickening tests  were  carried out using samples taken from blanket slurry
     which was formed under the conditions of 250mm/min  of overflow rate, 40
     to 50mg/l  of alum dosing rate and l.Omg/1 of polymer dosing rate. A column
     of the diameter of 70mm and  the height of 120mm was  used for the tests.
     An example of the results is shown in Fig. 4.15 Sludge concentration reached
     28 to 35g/l after 24 hours. From this result, it may be said that thickening-
     characteristic is comparatively good.
vii)  Quality  of effluent
     Table 4.13 shows quality of effluent which  was  obtained  at  the optimum
     dosing rates of coagulants, and at overflow  rates less than 280mm/min. It is
     considered that effluent quality has  no relation  directly with changes in the
     quality of  influent.  Insoluble CODMn, and insoluble BOD were removed very
     effectively. Concentration of CODMn remaining in effluent is about 10% lower
     than that of soluble  CODMn in influent.  From this, it can be  considered that
     part  of soluble CODMn  in  influent was also  removed.  Orthophosphate was
     removed very effectively although the orthophosphate concentration was rela-
     tively low, 0.8~1.4mg/l.

 4.4.3   PILOT PLANT EXPERIMENT  AT THE SHINHAMA SEWAGE TREAT-
        MENT PLANT, FUKUYAMA  CITY
     Experiments at  the Shinhama Sewage Treatment Plant have been carried out
with effluent from the plant. Worse in quality than that of the Senda Sewage Treat-
ment Plant. They have been conducted with the following three types of effluents:
     Type  A:   Effluent  from modified activated sludge treatment process which
                is overloaded.
     Type  B:   Mixed effluent of three types of effluents, i.e.,  that  from the
                conventional  activated sludge treatment facility,  that  from the
                overloaded modified activated sludge treatment facility, and  that
                from  the primary setting tank.
     Type C:   Mixed effluent of two types of effluents, i.e., that from the over-
                loaded modified  activated sludge treatment facility, and that from
                the primary settling tank.
     Qualities of these  types of influents during each test period are  shown in Table
4.14. Relations between CODMn  and CODcr  of Type  A and Type  B  are shown  in
Fig. 4.16.  In  the Figure both total COD  and soluble COD are plotted and a  high
correlation is  found in both cases.
                                  - 171  -

-------
     As with experiments in Hiroshima, coagulants used in this pilot plant tests were
alum and polymer. The dosing rates of them are shown in Table 4.14. The overflow
rate was in the range of 330 to 350mm/min.
     Quality of effluent obtained in this experiment is shown in Table 4.14. Also,
Fig. 4.17 shows removal characteristics of CODMn in the experiment. Summary of
the results are as follows:
a.    Total CODMn  of effluent depends on the concentration of soluble CODMn  in
     influent.
b.    Total CODMn  in effluent is always lower than soluble CODMn in influent.
     From this, it is concluded that insoluble CODMn in influent is removed almost
     completely and a part of soluble CODMn in influent (15~20%) is also removed.
c.    Relations between soluble CODMn  in influent and that in effluent are shown in
     solid line in Fig. 4.18. Relations between soluble CODMn in influent and total
     CODMn in effluent are shown in a broken line in the same figure. From  Fig. 4.
     18, it can be considered that 35% of soluble CODMn in influent was transferred
     into insoluble  CODMn by the flocculation-sedimendation process, 30 to 35%
     of which was removed in the sludge blanket.
d.    Fig. 4.19 shows the  relation between  total CODMn  and soluble CODMn in
    effluent.  From this Figure, it can be said that 80% of total CODMn  in effluent
    is soluble.
    Insoluble CODMn carried over from the overflow weir of this installation  is
    floe with comparatively low specific gravity which is formed by conversion of
    soluble CODMn in influent  into insoluble one through the flocculation-sedi-
    mentation process.
                                     172

-------
        Table 4.1   Coefficients a and b, and Standard Deviation of Regression Line
Coagulant




A12(S04)3







FeCl3








MICS




Mole
ratio
0.5
1
1.5
2
2.5
3
3.5
4
0.5
1
1.5
2

2.5
3
3.5
4
0.5
1
1.5
2

2.5
3
3.5
4
Influent to the primary settler

a
0.743
0.472
0.223
0.074
0.000
-0.029
-0.028
-0.039
0.671
0.448
0.248
0.088

0.014
0.006
0.001
-0.010
0.703
0.457
0.239
0.115

0.027
-0.002
-0.007
-0.008

b
0.149
0.390
0.632
0.693
0.610
0.497
0.368
0.343
0.381
0.486
0.703
0.877

0.782
0.539
0.381
0.332
0.214
0.368
0.517
0.490

0.469
0.363
0.230
0.167

a
0.218
0.266
0.255
0.169
0.158
0.144
0.121
0.091
0.194
0.315
0.363
0.402

0.388
0.278
0.238
0.042
0.128
0.240
0.276
0.229

0.201
0.181
0.103
0.067
Secondary effluent

a
0.692
0.465
0.266
0.119
0.057
0.011


0.807
0.545
0.360
0.234

0.146
0.094


0.810
0.561
0.331
0.148

0.029
-0.002



b
0.156
0.272
0.316
0.357
0.318
0.271


0.030
0.207
0.306
0.282

0.270
0.240


0.024
0.163
0.279
0.358

0.373
0.328



a
0.122
0.170
0.211
0.209
0.188
0.133


0.147
0.153
0.156
0.104

0.098
0.071


0.103
0.099
0.138
0.131

0.113
0.087


The number of data is 14 or 15.
                                          - 173

-------
                       Table 4.2   Objective of Dissolved  Phosphorus Removal vs. Coagulant Dosage and Mole Ratio
                                                                                                               Influent to the primary settler
P-D in
influent
(mg/B)
2
4
6
8
10
2
4
6
8
10
2
4
6
8
10
2
4
6
8
10
2
4
6
8
10
Objective
P-D in
effluent
(mg/E)


0.1




0.2




0.3




0.5




1.0


A12 (S04)3
Mole
ratio
_
—
4.1
3.7
3.5
—
3.8
3.5
3.2
3.0
3.6
3.3
3.0
2.9
2.8
2.8
2.7
2.7
2.6
2.6
1.6
2.0
2.1
2.2
2.2
Al(mg/£)


21.4
25.8
30.5

13.2
18.3
22.3
26.1
6.3
11.5
15.7
20.2
24.4
4.9
9.4
14.1
18.1
22.6
2.9
7.0
11.0
15.3
19.2
FeCl3
Mole
ratio
	
_
—
—
-
_
—
—
—
-
(4.2)
3.9
3.9
3.8
3.7
3.1
3.2
3.2
3.3
3.3
2.3
2.4
2.4
2.5
2.5
Fe(mg/e)










(15.1)
28.1
42.1
54.7
66.6
11.1
23.0
34.6
47.5
59.4
8.3
17.3
25.9
36.0
45.0
MICS
Mole
ratio
	
—
—
(4.1)
3.7
3.6
3.5
3.5
3.4
3.3
3.3
3.2
3.2
3.2
3.1
2.5
2.6
2.7
2.7
2.8
1.5
1.9
2.1
2.3
2.3
Al + Fe
(mg/fi)



(31.8)
35.9
7.0
13.6
20.4
26.4
32.0
6.4
12.4
18.6
24.9
30.1
4.9
10.1
15.7
21.0
27.2
2.9
7.4
12.2
17.9
22.3
Objective
P-D
removal
(%)


98




95




90




85




80


A12 (S04)3
Mole
ratio
	
_
4.0
3.4
3.0
—
3.8
3.0
2.8
2.6
—
3.0
2.5
2.3
2.2
3.6
2.5
2.2
2.1
2.0
3.1
2.2
1.9
1.8
1.8
Al(mg/£)


20.9
23.6
26.1

13.2
15.7
19.5
22.6

10.4
13.1
16.0
19.2
6.3
8.7
11.5
14.6
17.4
5.4
7.7
9.9
12.5
15.7
FeCl3
Mole
ratio
	
_
—
—
-
—
—
3.8
3.5
3.3
—
3.5
2.9
2.6
2.5
(4.2)
2.9
2.5
2.2
2.1
3.5
2.6
2.2
2.0
1.9
Fe(mg/£)







41.0
50.4
59.4

25.2
31.3
37.4
45.0
(15.1)
20.9
27.0
31.7
37.8
12.6
18.7
23.8
28.8
34.2
MICS
Mole
ratio
	
_
4.0
3.5
3.3
_
3.6
3.2
2.9
2.8
3.6
2.9
2.6
2.4
2.3
3.3
2.5
2.2
2.1
2.0
2.8
2.2
2.0
1.9
1.8
Al + Fe
(mg/B)


23.3
27.2
32.0

14.0
18.6
22.5
27.2
7.0
11.3
15.1
18.6
22.3
6.4
9.7
12.8
16.3
19.4
5.4
8.5
11.7
14.8
17.5
Al/p = 27/31 =0.871     Fe/p = 55.8/31 = 1.8

-------
                                Table 4.3  Objective of Dissolved Phosphorus  Removal vs. Coagulant Dosage and Mole Ratio
                                                                                                                                   Secondary effluent
P-D in
influent
(mg/fi)
1
2
3
1
2
3
1
2
3
Objective
P-D in
effluent
(mg/£)

0.3


0.5


1.0

A12 (S04)3
Mole
ratio
2.9
3.0
3.0
1.9
2.2
2.4
0
1.3
1.6
Al(mg/£)
2.5
5.2
7.8
1.7
3.8
6.3
0
2.3
0.2
FeCl3
Mole
ratio
(33)
-
-
2.1
2.7
3.1
0
1.5
2.0
Fe(mg/£)
5.9
-
-
3.8
9.7
16.7
0
5.4
10.8
MICS
Mole
ratio
(3.3)
(3.2)
(3.1)
2.0
2.3
2.4
0
1.4
1.8
Al + Fe
(mg/fi)
(3.2)
(6.2)
(9.0)
1.9
4.5
7.0
0
2.7
5.2
Objective
P-D
removal
(%)

90


85


80

A12 (S04)3
Mole
ratio
—
(3.5)
3.0
—
3.0
2.6
(3.5)
2.6
2.3
Al(mg/£)

6.1
7.8

5.2
6.8
3.0
4.5
6.0
FeCl3
Mole
ratio
—
-
-
—
-
(3.3)
—
(3.2)
2.8
Fe(mg/£)
—
-
-
_
-
17.8
—
11.5
15.1
MICS
Mole
ratio
—
-
(3.1)
—
(3.2)
2.5
—
2.7
2.2
Al + Fe
(mg/C)


(9.0)

(6.2)
7.3

5.2
6.4
tn

-------
Table 4.4   Comparison between Constant Feed and Mole Ratio Control (Influent flow is constant.)
Mole ratio
(Al/p)
1
2
3
Dissolved phosphorus
Items
Lo*
Co**
Re***
Lo
Co
Re
Lo
Co
Re
Influent
7.01
3.36
—
7.01
3.36
—
7.01
3.36
-
Constant
feed®
4.46
2.14
36
2.38
1.14
66
0.89
0.43
87
Mole ratio
control (b)
4.07
1.95
42
2.06
0.99
71
0.73
0.35
90
©/®
0.91
-
0.86
-
0.81
-
®
-------
                   Table 4.5  Coefficients of  Regression Lines of Fig.  4.9
Dissolved phosphorus
in influent
3.36mg-P/8 max.
3.36mg-P/2 min.
Coefficient
a*
b*
r**
a
b
r
Mole ratio (Al/p)
1
0.574
-1.984
0.884
0.110
-0.504
0.311
2
0.606
-2.200
0.873
0.189
-0.738
0.754
3
0.452
-1.640
0.977
0.091
-0.430
0.553
 * [(P-D in effluent treated by constant feed) - (P-D in effluent treated by mole ratio controle)]
   = a • [P-D in influent] + b
** correlation coefficient
                                           - 177

-------
Table 4.6   Comparison between Constant Feed and Mole Ratio Control (Influent flow changes.)
Mole ratio
(Al/p)
1
2
3
Dissolved phosphorus
Items
Lo*
Co**
Re***
Lo
Co
Re
Lo
Co
Re
Influent
7.48
3.59
-
7.48
3.59
-
7.48
3.59
-
Constant
feed @
4.84
2.32
35
2.65
1.27
65
1.04
0.50
86
Mole
ratio
control
4.34
2.08
42
2.20
1.06
71
0.72
0.35
90
©1®
0.90

0.83

0.69

®-®
0.50
0.24
-7
0.45
0.21
-6
0.32
0.15
-4
Al dosage
Constant
feed ©
6.11
12.22
18.33
Mole
ratio
control
6.52
13.04
19.55
a/©
1.067
  *Lo: load (kg-P/D)
 **Co: average concentration (mg-P/C)
   ' Re:  removal (%)
                                          178

-------
          Table 4.7  Comparison between Constant Feed and Mole Ratio Control
Mode
ratio
in
cons-
tant
feed
1
2
3
Correspondence of influent
flow and dissolved
phosphorus in influent
Direct proportion****
Actual correspondence****
Influent flow is constant
****
Inverse proportion
Direct proportion
Actual correspondence
Influent flow is constant
Inverse proportion
Direct proportion
Actual correspondence
Influent flow is constant
Inverse proportion
Mole ratio
in mole
ratio control
0.83
0.94
1.00
1.17
1.66
1.87
2.00
2.34
2.48
2.81
3.00
3.50
Dissolved phosphorus
Item
Lo*
Co**
Re***
Lo
Co
Re
Lo
Co
Re
Lo
Co
Re
Lo
Co
Re
Lo
Co
Re
Lo
Co
Re
Lo
Co
Re
Lo
Co
Re
Lo
Co
Re
Lo
Co
Re
Lo
Co
Re
Influent
8.46
4.06
_
7.48
3.59
—
7.01
3.36
—
6.00
2.88
—
8.46
4.06
—
7.48
3.59
—
7.01
3.36
—
6.00
2.88
—
8.46
4.06
—
7.48
3.59
-
7.01
3.36
—
6.00
2.88
-
Constant
feed @
5.86
2.81
31
4.85
2.32
35
4.46
2.14
36
3.54
1.70
41
3.26
1.56
62
2.65
1.27
65
2.38
1.14
66
1.75
0.84
71
1.34
0.64
84
1.04
0.50
86
0.89
0.43
87
0.58
0.28
90
Mole
ratio
control
®
5.30
2.54
37
4.50
2.16
40
4.07
1.95
42
3.34
1.60
44
2.97
1.42
65
2.40
1.15
68
2.06
0.99
71
1.52
0.73
75
1.38
0.66
84
0.92
0.44
88
0.73
0.35
90
0.37
0.18
94
® / ®
0.90
—
0.93
-
0.91
—
0.94
-
0.91
—
0.91
—
0.86
—
0.87
—
1.03
—
0.88
-
0.81
—
0.64
-
®-®
0.56
0.27
-6
0.35
0.16
-5
0.39
0.19
-6
0.20
0.10
-3
0.29
0.14
-3
0.25
0.12
-3
0.32
0.15
-5
0.23
0.11
-4
-0.04
-0.02
0
0.12
0.06
-2
0.16
0.08
-3
0.21
0.10
-4
 *Lo: load (kg-P/C)
**Co: average concentration (mg-P/C)
 ***
#***
Re: removal (%)
refer to Fig. 6
                                        - 179  -

-------
Table 4.8   Operation Condition of Alum Precipitation and  Filtration
Process
Influent
Alum precipitation
Filtration
Condition
Secondary effluent
Coagulant A12(S04)3
Dosage 3.9 mg-Al/2
Influent flow 216m3/D
Overflow rate of alum sedimentation tank 50m3/m2-D
Gravity flow, constant head, dual media
Initial flow rate 218m/D
Total head loss at filtration end
                                180

-------
       Table 4.9   Results of Alum Precipitation and Filtration at Yokosuka Pilot Plant

Temp. (°C)
pH
Turbidity
SS
P
P. ortho
CODcr.
CODMn.
BOD
ABS
Common bact.
Colo-form bact.
mg/C
%*
mg/C
%
mg-P/C
%
mg-P/e
%
mg/£
%
rng/2
%
mg/C
%
mg/e
%
N/mC
%
N/mC
%
Influent
(secondary effluent)
11.7
1.22
21.1

10.5

1.782

1.309

45.8

14.3

14.6

0.192

3 1 ,000

3,600

Effluent from alum
sedimentation tank

6.96
18.2
32.7
6.9
34.2
0.691
61.2
0.472
63.9
30.6
33.1
10.4
27.3
6.5
55.7
0.180
6.3




Effluent from
filter

7.12
2.3
91.4
1.3
87.7
0.173
90.3
0.109
91.7
23.8
48.1
7.1
50.6
4.5
69.0
0.127
33.9
19,000
38.7
340
90.6
* Removal to influent
                                        -  181

-------
                 Table 4.10   Results of Alum Sedimentation Tank Operation
Alum Dosage:   3.9 mg. A2/2
Overflow Rate  of Alum Sedimentation Tank:   50 m3/m2 -D
^"^\^^ Condition
Item ^~"^-^^^
Temp, of influent (°C)
PH
SS (mg/2)
P (mg/J2)
P-D (mg/B)
© *
(T> **
©
©
©
©
©
©
Fe+++ addition (mg/2)
0
18.7
7.20
6.92
22.8
13.0
1.487
0.348
0.836
0.061
0.5
19.5
7.34
6.98
24.0
14.5
1.906
0.461
1.331
0.105
2.0
20.5
7.24
6.93
31.0
15.4
3.320
0.663
2.265
0.142
5.0
19.9
7.28
6.89
27.0
13.8
2.054
0.689
1.666
0.100
P.eturn sludge (% to influent flow)
0
22.0
7.24
7.03
9.4
12.7
2.538
0.783
1.882
0.270
10
21.3
7.29
6.96
11.6
8.1
1.709
0.695
1.226
0.044
20
21.0
7.22
6.92
16.8
13.7
2.170
0.779
1.569
0.233
30
22.2
7.42
7.09
37.0
15.1
2.020
0.590
1.297
0.076
Polymer addition (mg/C)
0
24.5
7.46
7.11
4.3
5.7
1.895
0.118
1.155
0.127
0.1
24.6
7.26
7.12
11.7
12.6
1.864
0.194
1.647
0.212
0.5
24.8
7.36
7.08
25.0
14.4
1.156
0.347
0.649
0.065
* © Influent (secondary effluent)    ** (2) Effluent from alum sedimentation tank

-------
Table 4.11  Constitution of  Filtration Media

Anthercite coal
Silica sand
Depth (cm)
Effective size (mm)
Uniformity coefficient
Depth (cm)
Effective size (mm)
Uniformity coefficient
No. 1 filter
30
0.8
1.4
30
0.45
1.2
No. 2 filter
30
1.2
1.4
30
0.55
1.2
                      183

-------
               Table 4.12   Results of Alum Sludge Dewatering by Centrifuge

                                 Character of Feed Sludge (Thickend Sluge)
                                   Water Content = 98.6%,  A£ = 131 mg/g-dry sludge
                                   P = 36.8 mg/g-dry sludge, VSS = 463 mg/g-dry sludge
ExpeA
No. \
1
2
3
4
5
6
Experiment condition*
Centirfugal
force (G)
1,000
2,000
3,000
2,000
2,000
2,000
Sludge feed
rate (m3/h)
1.26
1.38
1.40
0.46
0.81
1.79
Conveyer
revolution
(rpm)
6
6.5
8
6.5
6.5
6.5
Dewatered sludge
Rate of total
solid captured
(%)
28.7
26.2
33.8
48.4
35.1
22.5
Water content
(%)
86.9
86.7
86.0
88.2
86.6
85.4
Suspended
solids in
centrate (g/2)
10.5
9.7
9.0
7.0
8.7
10.3
'Pool depth is 1.5-2.4 mm.
                                          184

-------
Table 4.13   Influent and Effluent Quality of the Highrate
             Chemical Coagulation Clarification  System
Item
Suspended solid (mg/C)
PH
M-Alkalinity (mg/£)
Total-CODMn (mg/K)
Soluble-CODMn (mg/E)
Suspended-CODMn (mg/C)
Total-BOD5 (mg/2)
Soluble-BOD; (mg/£)
P04- (mg/fi)
Influent
Range
12 ~ 32
6.95- 7.65
102 -140
7.4 ~ 11.0
5.8 - 8.1
1.3 ~ 7.0
7.6 ~ 14.0
2.8 ~ 3.3
0.8 ~ 1.4
Mean
18
7.2
-
9.0
6.5
2.2
11.2
3.0
0.9
Effluent
range
1~10 (2-3 almost)
-
-
4.8-7.7
4.3-6.8
-
trace —3.0
trace —1.0
trace
                              -  185

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Table 4.14  Water Quality of Influent and  Effluent, and Chemical Dosing  Rate
Items
Suspended solid
pH
M-Alkalinity
Total CODMn
Soluble CODMn
Total CODcr
P04
BODS
Alum dosing rate
Polymer dosing rate
Unit
mg/S

rng/C
mg/£
mg/e
mg/e
mg/£
mg/e
mg/£
mg/£
Type A
Influent'
18 ~ 47
7.15- 7.6
140 -270
20 ~ 40
10 ~ 27
80 -166
3.3 ~ 11
18 ~ 30
Effluent
2 -14
6.4- 6.8
-
9.5-22.5
7.6-18.4
67 -96
0.5- 1.6
3-6
60-80
1-1.2
Type B
Influent
13 -145
7.15- 7.58
117 -310
21 -106
15 ~ 40
144 -197
1.8 ~ 14
20 ~ 30
Effluent
4-25
6.3- 6.7
-
10 ~ 36
10 - 25
96 -108
0.9~ 1.4
4~22
90-130
1-1.2
Type C
Influent
19 -248
7.25- 7.5
143 -270
19 ~ 74
13 - 39
-
-
106
Effluent
-15
6.3- 6.8
-
8 -30
11.1-15.5
-
-
30.5
80-140
1-1.2

-------
                                           7 -,
00
                                           4 .
                                           3 -
                                                                           D  D'
                                                           n
                                                              ±
                                                         04A
                                                                                                   • Influent to the Primary Settler, Mole Ratio 1
                                                                                                   rj Secondary Effluent, Mole Ratio 1
                                                                                                   A Influent to the Primary Settler, Mole Ratio 2
                                                                                                   A Secondary Effluent, Mole Ratio 2
                                                                                                   • Influent to the Primary Settler, Mole Ratio 3
                                                                                                   O Secondary Effluent, Mole Ratio 3
                                                                                                   Coagulant:  M2 (S04)3
                                                                                       A    A
                                                                                            A     A
                                                                                      •     *     •
                                             0      1
3     4     5     6     7     8     9     10    11     12    13     14    15
                  Phosphorus in Influent (mg-P/2)
                                           Fig. 4.1   Phosphorus in Influent vs. Dissolved Phosphorus in Effluent  (Mole ratios are based on
                                                     phosphorus in influent.)

-------
    7  ,
OO
E
 3
 O
_C
 OH
 C/O
 o
a.
•o
              •  Influent to the Primary Settler, Mole Ratio 1
              D  Secondary Effluent, Mole Ratio 1
              A  Influent to the Primary Settler, Mole Ratio 2
              A  Secondary Effluent, Mole Ratio 2
              •  Influent to the Primary Settler, Mole Ratio 3
              O  Secondary Effluent, Mole Ratio 3
              Coagulant:  A22 (S04)3
                        a        D
                         *n    • D
                 a aa
                               A    A
                       o
                    o     •  o  o
                                          •   •
             1      2345678

                    Dissolved Phosphorus in Influent (mg-P/2)

         Fig. 4.2  Dissolved Phosphorus in Influent vs. Dissolved
                  Phosphorus in Effluent (Mole ratios are based
                  on dissolved phosphorus in influent.)
                              -  188

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  100-




   90-



   80-




  ' 70-
"I 60-
o
   SO
   -''-' ~
Q 40-
g  30-


I
   20-
   10-




    0
Sample: Influent to the Primary Settler

Coagulant:  AC2 (S04)3
      0123      4567      89


                       Dissolved Phosphorus in Influent (mg-P/2)



            Fig. 4.3  Dissolved Phosphorus in Influent vs. Removal

                     of Dissolved Phosphorus
                                     10
                                 189

-------
            Sample: Influent to the
                    Primary Settler
            Coagulant:  A£2 (S04)3
          1234
             Mole Ratio
Fig. 4.4  Mole Ratio vs. Dissolved
         Phosphorus in Effluent
              190  -

-------
      Sample:  Influent to the Primary
               Settler
      Coagulant: A£2 (S04)3
Sample:  Influent to the Primary
         Settler
Coagulant: A£2  (S04)3
         Mole Ratio
Fig. 4.5  Mole Ratio vs. a
Fig. 4.6   Mole Ratio vs. b

-------
  200
oo
    6  •
    5  -
2  4
o

c.

2  3
•3  2
   1 -
   0 J
                                                                                      [Mole Ratio Control]
[Constant Feed]
                                                                                                     Mole Ratio 1    Mole Ratio 3
                                10    12    14    16    18     20    22    24       246
                                                                                                        10     12   14    16    18    20    22   24
                                Fig. 4.7   Relationship between Influent Flow, Dissolved Phosphorus Concentration, and Time

-------
O
.s
100,

 90.


 80-

 70-

 60-


 50"

 40.


 30-

 20-

 10
     0
                                  [Constant Feed]
       01      234567

          Dissolved Phosphorus in Influent (mg-P/S)
                                                          100
                                                           90 •
                                                           80'
                                                           70 -
>  60
I
V
*  50
                                                        o
                                                        a- 40
                                                           30 -
                                                        Q  20 -
                                                           10 -
          [Mole Ratio Controle]
                        O
               Mole Ratio (AB/P)
            O     3
            A     2
            D     1
             1      234567

           Dissolved Phosphorus in Influent (mg-P/£)
                         Fig. 4.8   Dissolved Phosphorus in Influent vs. Dissolved Phosphorus Removal

-------
oo
o
O
Pi
_«
 o
§
 (U
  _c
  Q

   I
  •a"
 o
U
2.4 -

2.2 -

2.0


1.8 •

1.6

1.4 •

1.2

1.0 -

0.8 •

0.6

0.4

0.2
I
w   _
 Q
 a.
          0

        0.2

        0.4

        0.6
                a Mole Ratio 1
                A Mole Ratio 2
                • Mole Ratio 3
                                                        A

                                                        D
                                                 Mole Ratio 3
Fig. 4
          01234567
                  Dissolved Phoshorus in Influent (mg-P/2)

    9   Dissolved Phosphorus  in Influent vs. Difference of
        Dissolved Phosphorus  in Effluent between two
        Coagulant Feed Methods
                       -  194  -

-------
   noo •



   1000 -




    900




    800


ST

?"  700-
OO



o  600 -

o.
o
£  500

  300 -
c
T3
03

5  200-
100 -
                                                (Constant Feed)
                                      Influent
(Mole Ratio Control)
                                                                                                            Influent
                                                                                                     10    12    14    16    18    20   22    24
                                       Fig. 4.10  Relationship between  Loading of Dissolved Phosphorus and Time

-------
 tq
  G
  o

  a.
  CO
  o
  J=l
  0,

  -a
  tu
  _>

  "o
      7 -
      6 -
     4  -
                Constant Feed
Mole Ratio Control
       0123


                         Mole Ratio (Al/P)



Fig. 4.11   Mole Ratio vs. Dissolved Phosphorus Load

           in Effluent
                       196

-------




t Flow(m3/h)
Influeni



200 -,
180 -
160 -
140 -
120 •
100 -
80 -
60 -
40 -
20 -
n
0
o
o

0
UD
0
o
o
o
o
o o
0
o
0 0
0
&°0

    200-





    180-





    160-





    140-






•?  120-





|  100-



"c
OJ

,H   80 .

C




     60






     40 -





     20 -






      0
                                                                                          10
01     234567


     Dissolved Phosphorus in Influent (mg.P/^)




 (Influent Flow is in Direct Proportion to Phosphorus)
                                                                                         13
                                                                 Hour is indicated by number.




p
0
u_
0)
i:
c:



200 '
180 -
160 -
140 '
120 -
100 -
80 -
60 -
40 -
20 -
0
0
0
o

o
o
o
o
o
0
0
°0
o
0 0
o
00° O

        01      234567


            Dissolved Phosphorus in Influent (mg-P/v.)




        (Correspondence of Influent Flow and Phosphorus

        is Actual)
01234567


    Dissolved Phosphorus in Influent (mg-P/t)




 (Influent Flow is in Inverse Proportion to


 Phosphorus)
                       Fig. 4.12   Relationship between Dissolved Phosphorus and Influent Flow  Used for Calculation

-------
OC
                                  Alum Dosing Pump
                                                                                                                                      Fresh Water
                         Electromagnetic Flow Meter
                                                                                                                  	Signal from Sludge Lebel Sensor
                                                                                                                                      Excess Sludge
                                                                                                                                      Effluent
                          Influent
                                                        Fig. 4.13   Flow Diagram of High Rate Chemical Coagulation and Clarification

-------
    30  —i
    20  —
CX



vf


•g



1
I—I

<+-(
O
(/)
T3

"o
in
T3

I   10
                         o     o
          5                             10                            15


                             Total CODMn of Influent (mg/£)


           Fig. 4.14  Corelation  between Suspended Solids and Total CODMn
                                   199

-------
o
o
               -o
               c
               3
               o
               03
GO
c*-
O


BO
                                                                              Over Flow Rate               250 mm/min
                                                                              Alum Dosing Rate             50 mg/Q
                                                                              Polymer Dosing Rate           1 mg/£
                                                                              Initial Concentration of S.S.    3.3 g/8
                                                                              Ultimate Concentration of S.S. 2.8 g/6
                                                                                        (after 24 hr)
                   40 -
                   20  -
                                                                                                   120
                                                                                         Settling Time
                                                                            Fig. 4.15  Settability of Excess Sludge
                                                                                                        150
180  min
24 Hr

-------
     250  -,
     200  -
     150  -
c*

~S2
 u
Q
O
U
100 -
      50  -
                       i

                      10
                             I

                            20
 r
40
                                30


                          CODMn (mg/<9


Fig. 4.16   Corelation between CODMn and CODCr of Influent
 I

50
                                    201

-------
                     Blend A
                        Soluble CODMn of Influent (mg/C)





Fig. 4.17   Corelation of Inf. Solube CODMn and Eff. Total COD

-------
01
                                30-,
                                25-^
                             I  20-

                             £
                             pa
                             I 15
                             u
                                 10
                              +J
                              o
                              H
    /
                                                                                              X
                                                                                                  /
                                                                                                     /
                                                                                                       /
                  /»
/
  /

/ 0/ 2/
/* X
/ / /
// y
/ X
o /
/*

-1 	 1 1
10 15 20
^0°



® 	 Total CODMn, Eff.

9 O 	 Soluble CODMnj Eff.
	 1 : l Line
1 1 r~
25 30 35
                                                5



                                                                   Soluble CODMn of Influent (mg/£)



                                 Fig. 4.18  Corelation between Total or Solube CODMn of Effluent and Solube CODMn of Influent

-------
INJ
o
                                   25  -J
                                   20  -J
                               3
D
O
o
                               O
                              CO
                                   15  -J
    10 -J
                                                               I

                                                               10
                                             I

                                             15
20
25
30
                                                                    Total CODMn of Effluent


                                                      F\g. 4.19  Corelation between Total CODMn  and Soluble

                                                                CODMn of Effluent

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CHAPTER 5.  LIME PRECIPITATION AND  RECOVERY OF CALCIUM
              CARBONATE
5.1    Results of Precipitation	206
  5.1.1   Lime Slaking	206
  5.1.2   Results of Lime Sedimentation Tank Operation  	207
  5.1.3   Phosphorus Resolubilization from Floe Containing Phosphorus
5.2    Experiment on Scale Formation of Calcium Carbonate
5.3    Recovery of Calcium Carbonate from Lime Sludge. . .,	210
  5.3.1   Results by Centrifuge  	2l°
  5.3.2   Results of Recarbonation of Lime Sludge	212
  5.3.3   Summary	213
                                  205

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5.    LIME PRECIPITATION AND  RECOVERY OF CALCIUM CARBONATE
     The results of lime precipitation at the Yokosuka Pilot Plant were reported at
the Third  U.S.-Japan Conference on Sewage Treatment Technology. This report is a
summary of experimental results after the Conference. These experiments have the
following three points which are different from former ones:
a.    Quick Lime instead of slaked lime is used for making lime slurry.
b.    Rapid  mixing  tank,  flocculation  tank  and lime  sedimentation  tank  are
     connected by open channels instead of piping. Before the modification, due to
     scaling of calcium carbonate in piping, roughness increased and cross sectional
     area  decreased,  and thus, water levels  in tanks became high,  and sometines
     causing overflow of water from tanks.
c.    Sludge thickener and centrifuge are added.

5.1  RESULTS OF PRECIPITATION
5.1.1  LIME SLAKING
     Lime slaking is performed as  follows:  powder quick lime (residue  on a 88-
micron  mesh sieve is less  than 5%) is stocked in the hopper; a fixed quantity of
quick lime is  continuously raked out with  a volumetric feeder mounted at the
bottom  of  the hopper; the  quick  lime is sent to the slaking tank by  a  screw
conveyer;  the  water  level in the slaking tank is kept constant by a hold-up  valve.
Under  the conditions of this experiment, i.e., 9m3/h of influent flow,  SOOmg;
Ca(OH)2/l  of lime  dosage and  10% of the concentration  of lime slurry,  the
retention  time in  the slaking tank is 60 minutes. Problems in slaking operations so
far are summed up as follows:
a.    Average pH value after lime is added to sewage was 10.3 during the period that
     slaked lime was used  and 10.5 during the period slaked quick lime was used
     (Ca(OH)2 dosage, SOOmg/1). From this, it is considered that use of slaked
     quick lime creates no problem in terms of pH values.
b.    Impurities contained in quick lime  (almost all of them is sand) accumulate in
     the slaking tank. Purity of quick lime is about 95%. Because of this, clogging of
     the lime slurry feed pump occurred. Therefore, the slaking  tank is drained once
     a day. Drained slurry is returned to the rapid mixing tank.
c.    The bottom  of the quick lime hopper slants 45 degrees and is connected to the
     volumetric feeder. This slanting and a vibrator were provided in an attempt to
     prevent bridge of  quick lime in the hopper but they  were not  sufficient. The
     vibrator caused quick lime to  drop in bulk at a time, thereby changing the
     apparent  specific gravity of quick lime being supplied to the volumetric feeder.
     To avoid  this, once every  two hours, a stick is used to poke the hopper from its
     upper portion to prevent bridge.
d.    Calorific  value  when  quick lime is slaked is  15.5kcal/g.mol. Under  the
     above-mentioned conditions  for slaking,  temperature  rise of 21°C is expected
     in  the slaking tank. Thus, if  water supply to the slaking tank is suspended due
     to  some reasom or other, only quick lime accumulates in the tank and tempera-
                                     206

-------
     ture in the tank goes up. To prevent this a teperature warning device is provid-
     ed in  the slaking tank, which acts to suspend supply of quick lime when the
     temperature  reaches 65°C. But thus far this device has not given a warning:
     temperature increase of lime slurry flowing out of the slaking tank has been less
     than 10°C.

5.1.2  RESULTS OF LIME SEDIMENTATION TANK OPERATION
     Table  5.1 shows average values of the results of the lime sedimentation tank
operation during the period between November,  1973 and March, 1975. Under the
operational conditions which are also indicated in the Table, the settling efficiency
of the sedimentation tank did not show significant changes. Therefore, from April,
1975, the conditions have been  changed as follows: FeCl3 = 0 to 5.0mg/l in terms
of Fe; return sludge ratio = 0 to 30%; anionic polymer  dosage = 0 to l.Omg/1; and
overflow rate =  10  to  100m3/m2.d.  Also, a shallow  setting device will be insta-
led.  Effects of these changes will be examined. Table 5.2 shows data obtaned up to
now.  From  these  data, it seems  that  additions  of Fe,  and  polymer and
relurn of sludge do not  contribute to improvement  in the removal of suspended
solids. But  it is  observed that through return of sludge the concentration  of
dissolved phosphorus in overflow from  the lime sedimentation tank decreases,
thereby reducing the phosphorus concentration.

5.1,3  PHOSPHORUS   RESOLUBILIZATION   FROM  FLOC  CONTAINING
       PHOSPHORUS
       From 9 a.m.,  August 20  to 9 a.m., August, 21, 1974,  a 24-hour survey
was  conducted at  the  Yokosuka Pilot  Plant, at  the  lime dosage  of  300mg
Ca(OH)2/l.  As a result,  the phenomenon  of  phosphorus resolubilization from
phosphorus-containing floe that is  carried over from  the sedimendation thank
was  confirmed.
     Table  5.3 shows average values of pH of  effluent from  each unit process,
phosphorus  concentration  and  dissolved phosphorus  concentration that were
obtained in  this  survey.  As  seen  in  the  Table,  while  the concentration  of
phosphorus  in the  effluent from  the  lime sedimentation tank is 0.514mg-p/l,
dissolved phosphorus  concentration is   0.044mg/l,  only  about 8%  of total
phosphorus.  But  as   sewage  flows   down  through   ammonia  stripping,
recarbonation  and   filtration,  the  percentage  of  dissolved  phosphorus  in
phosphorus  increases  sharply,  44%, 90%  and  99%,  respectively and dissolved
phosphorus,  which  is  0.044mg-p/l in  overflow  from  the lime sedimentation
tank, becomes  0.350mg-p/l  in  effluent  from filter,  about  8  times  of the
former.  It  is considered  that  this is because  decrease  in  pH  values  in the
processes after  the  sedimentation tank  causes resolubilization of  phosphorus
from  floe containing  phosphorus that is carried over from the sedimentation
tank.
     To confirm  this  phenomenon,  the  following  experiment was  conducted.
About 5mg/l of KH2PO4  as  P  was added  to distilled  water  to  make  acid
solution  of  orthophosphate;  200mg.Ca(OH)2/l  of  lime  was  added to  this
orthophosphate solution and the mixture was mixed for 10  minutes. After mixing,
                                   207

-------
pH was lowered using hypochloric acid. Imediately after pH ajustment, the solution
was again mixed and samples were taken. Samples were also taken 90 minutes and
180 minutes after pH adjustment with keeping the sotution mixed. pH and dissolved
phosphorus of these samples were analyzed  and the results are shown in Fig. 5.1.
The Figure indicates that phosphorus is resolved as pH is lowered and that  resolu-
bilization occurs in a short period of time.
     As  stated in the  above,  in  the  lime  treatment system  consisted of lime
precipitation — (ammonia stripping) — recarbonation — filtration,  phosphorus is
resolubilized as pH  decreases  from  floe  containing  phosphorus that  is  carried
over  from  the  lime  sedimentation  tank.  If two-stage  recarbonation  is applied,
non-dissolved   phosphorus   may   settle   more   in   the   calcium   carbonate
sedimentation  tank.  However,  it is  a reasonable assumption that  pH  of the
influent  to the calcium carbonate sedimentation tank is 9.5 to 10.0, in  which
range  pH  of  the effluent from the ammonia stripping  tower falls as  shown  in
Table  5.3.  The  dissolved phosphorus  concentration  in the  ammonia stripping
tower  effluent was 0.181mg-p/l,  which is about four times higher than that  in
the  effluent  from  the  lime sedimentation  tank, i.e.,  0.044mg-p/l.  Thus, not
only  when  single-stage  recarbonation  is  employed  but  also when  two-stage
recarbonation  is applied,  the  dissolved phosphorus concentration in  the filter
efflueut becomes higher than that in the effluent from the lime sedimentation tank,
it there exists floe contatining phosphorus carried over from the lime  sedimentation
tank. Therefore,  there arises the possibility  that phosphorus  removal capacity  of
lime precipitation is not displayed sufficiently.
     To prevent this, two measures are now being examined:
a.   Method  for  improving  the  removal   of  suspended   solids  in  the lime
     sedimentation tank
     See 5.1.2.
b.   System  in which  effluent  from  the  lime  sedimentation tank is directly
     filtered and floe  carried over is removed, and then water is  introduced to
     such processes as  ammonia stripping and recarbonation.

     The  latter method  might  have  a  problem: calcium  carbonate  scale  is
produced in the  media, etc. in the filter and  interferes operation of the  filter.
Taking  this problem into  consideration,  and on  the  basis of  observations as  to
forming  of calsium carbonate scale  stated in Section 5.2, the following experi-
ments  on  direct  filtration of the  effluent from the lime sedimentation tank are
schemed.
a     Study  on  receiving  methods of  influent  to  the  filter  to  prevent  scale
     forming;  contact between influent  and air is avoided as  much  as possible.
b     Study on  the constitution of filtration media.
c     Study on  filter  washing period, pH of washing water and  washing rate.
                                      208  -

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5.2  EXPERIMENT ON SCALE FORMATION OF CALCIUM CARBONATE
     The  fallowings are the  summary of observations  so far  obtained at  the
Yokosuka Pilot Plant as to scale produced in the lime precipitation process:
a.    90% of the scale is calcium carbonate.
b.    Quantity of scale  formation  in  a lower  temperature  is more than that in a
     higher temperature.
c.    Scale in the earlier stage of formation is relatively soft and can be removed by
     flashing of water.
d.   As a results of experiments with stainless steel,  steel, rubber, PVC and wood
     placed in the rapid mixing tank,  the lime  sedimentation tank and the lime sedi-
     mentation effluent holding tank, difference  in  materials has little effect on
     scale formation (Refer to Table 5.4).
e.    Quantity of scale  formation  was greater in the lime sedimentation  effluent
     holding tank  in which effluent from the lime sedimentation tank falls down
     together with air than in the lime sedimentation tank. Quantity of scale forma-
     tion in  the former was 2 to  1 times more than that in the  latter (See Tables
     5.4 and 5.5).
f.    Quantity of scale  began  to  increase sharply after  10 days (See Table 5.5).
                                    - 209

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5.3  RECOVERY OF CALCIUM CARBONATE FROM LIME SLUDGE
     At the Yokasuka  Pilot Plant, in order to recover calcium carbonate  in lime
sludge for reuse of lime, two processes were examined; one was that lime sludge is
put into a centrifuge for selective recovering of calcium carbonate contained in lime
sludge into dewatered sludge, and the other was that lime sludge is put to recarbona-
tion in order to refine the purity of calcium carbonate by dissolving away impurities.
     The raw  sewage  running  into  the  Shitamachi  Sewage Treatment Plant,  in
Yokosuka in which the pilot plant is constructed contains sea water, and accordingly
is rich in magnesium ions, seriously affecting lime treatment.
     Magnesium  ion is  precipitated  as  magnesium hydroxide, which are  highly
detrimental to  settlability, thickening rate and dewaterability of sludge.
     Therefore, of the experiments discussed here, the centrifugal dewatering was an
example  of low efficiency, and  recarbonization of lime sludge an example of so
much high efficiency as magnesium hydroxide was abundant.
5.3.1   RESULTS BY CENTRIFUGE
a)    Results of laboratory tests
     The thickened lime sludge  obtained from  the Yokosuka  Pilot Plant  was  de-
     watered in a laboratory centrifuge, and thus the dewatered sludge was separat-
     ed into three layers as shown in Fig. 5.2.
     Layers  were taken out one by  one, and dried.  After a drying, their specific
     gravity, and grain size  distribution were measured: the specific gravity and grain
     size  were recorded largest in the lower layer, followed by medium layer and
     upper layer in turn. (See Figs. 5.2 and 5.3).  The analytical  results of composi-
     tion of each layer are shown in Table 5.6.
     According to Table 5.6, about 83% of calcium carbonate in the thickened lime
     sludge is concentrated in the lower layer, and the ratio of calcium carbonate in
     the dry sludge is increased up to 75.3% in the lower layer as against  60% in feed
     sludge. On  the other hand, in  view of the  reuse of lime, the impurities of
     Mg(OH)2, Fe(OH)3, and Cas (OH)(PO4 )3  are increasing more and more, the
     higher the level becomes; in the lower layer, impurities are about 50% of those
     in the top or middle layer. Also, the lower  the layer, the smaller the water
     content in the sludge.
     Hence, the following conclusions are reached.
     1)   Lime sludge dewatered by the laboratory centrifuge is separated into three
         layers. This is because the  specific gravity and  grain size in  the bottom
         layer are larger than those in the top and middle layers.
     2)   Taking the lime  sludge as  being composed of calcium carbonate and im-
         purities, there is tendancy that calcium carbonate concentrates in the
         bottom layer, while impurities  are concentrated in the  top  and  middle
         layers.
     3)   The  water content in the bottom layer is smaller as compared  with that in
         the top and middle layers.
     In short,  calcium  carbonate in  the lime sludge is inferred  to have larger grain
                                     210

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     size and larger specific gravity than impurities and to be excellent in dewater-
     ability.
     The selective recovery of calcium carbonate by means of centrifuge is based on
     this principle;  the bottom layer shown in Fig. 5.2 is taken out as dewatered
     sludge, and impurities are conveyed into supernatant. In this way, relative pure
     calcium carbonate is concentrated as much as possible into dewatered sludge
     and at the same time the sludge is dewatered.
b)   Results of tests using the centrifuge for the pilot plant
     The centrifuge used  for the tests is the  modified one for the tests which is the
     smallest,  available in the market primarily for sewage sludge  dewatering pur-
     poses, (standard sludge feed rate: 1 m3/hr)
     Its specifications are  as follows.
         Bowl diameter:          2000 (mm)
         Bowl speed:             0 ~ 6,000 rpm
         Centrifugal force:        0 ~ 4,000 G
         Sludge feed rate:        0 ~ 1.85 m3 /hr
         Converyor revolution:    Variable (by stepless speed changer)
         Pool depth:             No. 1 (0.5 ~ 0.8 mm), No. 2 (1  -  1.6 mm),
                                No. 3 (1.5- 2.4mm)
     The lime sludge used for the tests was the thickened sludge  taken from the
     thickening tank in the pilot plant. Its characteristics, are shown in Fig. 5.4.
     For the tests, one out of the four factors—sludge feed rate, centrifugal force,
     pool depth and conveyor revolution—was taken as a  variable  while all the
     others were fixed constant. In this way,  the  effects of each factor upon the
     ratio of CaCCb captured as dewatered sludge,  ratio of CaCCh in dried sludge,
     and water content of dewatered sludge were investigated. The test results are
     shown in  Fig. 5.4.
     The following are found from Fig. 5.4.
     1)   By increasing the sludge feed rate, the absolute volume of CaCOs which is
         larger in settling rate than impurities can be  increased, improving the
         purity of CaCCh and decreasing  the water content so much. But  the
         capture of CaCOs gets lowered.
     2)   By increasing the bowl  speed, settling rate of solids in the feed  sludge
         toward bowl and the  density of sludge deposited on  the bowl  can be in-
         creased. But  the relative velocity  of CaCOs to impurities remains  un-
         changed.  Accordingly, the  capture of CaCOa increases,  and  the water
         content in  the  dewatered sludge decreases. But the purity of CaCOs re-
         mains unchanged.
     3)   Pool depth corresponds to the scraping-out depth of dewatered sludge. In
         the tests, if there are strata as shown in Fig. 5.2, it may be theoretically
         agreed that the  water content of dewatered sludge  can be decreased, and
         the ratio of CaCOs in dewatered sludge can be increased without changing
         the capture of CaCOs largely if the  pool depth is  adjusted to  the depth
         falling  just on  the  boundary surface between  the middle and bottom
                                  - 211 -

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          layers shown in Fig. 5.2. It is inferred that in the tests the pool depth was
          located above  the boundary surface between the middle  and bottom
          layers.
     4)    By increasing the conveyor speed, the detention time of sludge deposited
          on the bowl is shortened as sludge is discharged quickly one after another.
          Eventually, therefore, the pool depth is considered likely to become larger.
          Hence, it is concluded that to increase the conveyor speed is to increase
          the pool depth.
     To generalize the results within the scope of  the tests, the centrifugal force
     should preferably be set at 3,000 G and the pool depth at No. 1 (0.5 ~ 0.8
     mm) and the conveyor speed at 4.7 rpm. in order to obtain dewatered sludge of
     low water content and with high capture of calcium carbonate of high purity
     from lime sludge.
     The  sludge feed  rate, when increased, increases the purity of CaCCb in  the
     dewatered sludge, but decreases the capture of CaCCb to the contrary. Further
     investigations are needed  in  this  respect for the purpose of  finding out the
     optimum conditions.  The centrate contains a considerably large amount of
     solids (9,200 mg/lit.  to 13,500 mg/lit. in the  tests) as part  of solids in the
     thickened  sludge is  transfered into the centrate. For this reason,  the solids in
     the centrate  are required  to be dewatered  and  separated.  The results  of
     dewatering test on  the centrate  by means of the pilot plant centrifuge are
     shown in  Table 5.7. The centrate was hard to dewater; even when the cen-
     trifugal force was increased up to  3,000 G, the capture of solids was only 47.3
     % with the water content left as high as 84.8%. Thus, the centrate of centrate
     still contained no less than 6,500 mg/lit. of solids. Namely, sharp increase in
     the capture of solids is hardly expected unless chemical  dose  is practised.
     Use of dewatering aid, such as polymer, or practice of alternative method will
     be necessary.
5.3.2  RESULTS OF RECARBONATION OF  LIME SLUDGE
     Precipitation rates of CaCCb ,  Mg(OH)2, Cas (OH)(PC>4)2 , which are main com-
ponents of lime  sludge, are increased with rise in pH value, and they are solubilized
when pH  value declines.  If the solubilizing rate  of CaCCb is smaller  than that of
Mg(OH)2 and  Cas (OH)(PC>4 )3 ,  recarbonization  of lime sludge  can  improve  the
purity of CaCCb in the lime sludge, it will provide an effective way for the reuse of
lime sludge. Then,  the  recarbonation  of lime sludge was,tested at the Yokosuka
Pilot Plant, with the results shown in Fig. 5.5
     According to  Fig. 5.5, it is found  that  Yokosuka Pilot Plant's lime sludge used
for the tests has smaller solubilizing rate  of CaCCb with reduction in  pH  than
Mg(OH)2 's and Cas (OH)(PO4 )3 's, and therefore that it is feasible to recarbonate the
lime sludge. By recarbonating feed lime sludge from pH 11.29  to pH 8.11, CaCCb
was solubilized 16%, and Mg(OH)2 and Cas (OH)(PO<. )3 82% and 30%, respectively.
     In  that case,  the composition in  dried sludge  changed as shown in Fig. 5.6;
while CaCCb accounted  for 56.9%  in raw lime sludge, it increased  up  to 72% after
recarbonation. On the other hand, Mg(OH)2  changed from 22.8% to 6.1%.
                                     212

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5.3.3  SUMMARY
     In order to effectively recover lime from the lime sludge, it is necessary to re-
cover majority of calcium carbonate, the material of lime, with high purity and with
less water content in dewatered sludge, from the lime sludge in a preliminary stage.
     As ways to this end, the centrifuge  method and the recarbonation method were
examined, and the following conclusions are attained.
1)   Calcium carbonate contained in lime sludge is larger in grain size and specific
     gravity than  impurities  such  as magnesium  hydroxide  and  calcium  hydro-
     xyapatite, and is excellent in dewaterability.
     When lime  sludge is put to  centrifugal separation process, calcium carbonate is
     trapped selectively in the bottom  layer. By recovering the bottom deposit in
     the form of dewatered sludge, the above objective is achieved.
2)   There are four factors influential to the  centrifugal separation. They are sludge
     feed rate, centrifugal force, pool depth and conveyor vevolution. All these have
     effects on  the purity and capture  of calcium carbonate and water content of
     dewatered sludge.
3)   The optimum conditions in this test condition under which to operate the
     centrifuge  for dewatering lime sludge to recover lime are: centrifugal  force,
     3,000 G; pool  depth, No.  1  (0.5  ~  0.8 mm); conveyor  speed, 4.7 rpm.  As
     regards the sludge feed rate, further investigations are required.
4)   Solids in the centrate are hard to recover without chemical injection by cen-
     trifuge. It is therefore necessary to study alternative methods.
5)   As regards  the lime sludge used in the tests, recarbonization improves purity of
     calcium carbonate without degrading its capture.
                                    213 -

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Table 5.1   Results of Lime Precipitation (Average of 1973 ~ 1974)
           Experiment Conditions Lime Dosage 300 mg-Ca(OH)2/£
              Overflow Rate of Lime Sedimentation Tank:  33 ~ 50 m3/m2-day
              Polymer Dosage:  0 ~ 0.2 mg/£
              Return Sludge Rate:  0 ~ 20%

Influent (secondary effluent)
Effluent from lime sedimenta-
tion tank
Removal (%)
pH
7.24
10.53
-
Turbidity
(mg/£)
4.6
12.2
-
S S
(mg/fi)
4.1
19.5
-
P
(mg/£)
1.464
0.326
77.7
P, ortho
(mg/£)
1.265
0.262
79.3
BOD
(mg/£)
8.41
5.22
37.9
CODcr.
(mg/£)
31.9
25.4
20.3
                             214

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                             Table 5.2   Results of Lime Sedimentation Tank Operation
Lime Dosage:  300 mg-Ca(OH)2/C

Overflow Rate  of Lime Sedimentation Tank:  50m3/m2-D
^^"^^^^ Condition
Item ^^^^^
Temp, of influent (°C)
PH
SS (mg/C)
P (mg/fi)
P-D (mg/C)
© *
@**
©
©
(D
©
©
©
Fe+++ addition (mg/fi)
0
18.7
7.20
10.23
22.8
18.5
1.487
0.313
0.836
0.151
0.5
19.5
7.34
10.26
24.0
16.0
1.906
0.417
1.331
0.189
2.0
20.5
7.24
10.31
31.0
10.2
3.320
0.436
2.265
0.209
5.0
19.9
7.28
10.28
27.0
55.2
2.054
0.276
1.666
0.120
Return sludge (% to influent flow)
0
22.0
7.24
10.21
9.4
13.0
2.538
0.472
1.882
0.277
10
21.3
7.29
10.24
11.6
23.2
1.709
0.213
1.226
0.074
20
21.0
7.22
10.29
16.8
31.6
2.170
0.287
1.569
0.094
30
22.2
7.42
10.13
37.0
26.4
2.020
0.345
1.297
0.104
Polymer additon (mg/£)
0
24.5
7.46

4.3
21.6
1.895
0.452
1.155
0.287
0.1
24.6
7.26
10.35
11.7
27.0
1.864
0.403
1.647
0.163
0.5
24,8
7.36
9.31
25.0
40.5
1.116
0.182
0.649
0.104
to
h-'
          * ® Influent (Secondary effluent)    ** © Effluent from lime sedimentation tank

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Table 5.3   pH, Phosphorus (P), and Dissolved Phosphorus of Each Unit Process Effluent

Influent (secondary effluent)
Effluent from lime sedimentation
tank
Effluent from ammonia stripping
effluent
Effluent from recarbonation tank
Effluent from filter
PH
7.24
10.35
9.89
7.47
6.92
P (mg-P/£)
1.554
0.514
0.408
0.337
0.352
P-D (mg-P/J2)
1.511
0.044
0.181
0.304
0.350
P-D/P
0.972
0.081
0.444
0.902
0.994
                                     216

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        Table 5.4  Materials for Lime Precipitation Process and Scale Formation
                                                                 Water temp.: about  14°C
                                                                          pH: about  10.4
^~~"--\^^ Material
Setting place~""""~-\^^
Rapid mixing tank
Lime sedimentation
tank
Lime sedimentation
tank effluent Holding
tank
Stainless
steel
66.1*
5.2
19.6
Steel
68.4
6.1
22.2
Rubber
67.8
6.8
17.1
P.V.C.
71.7
5.9
23.7
Planed
wood
62.2
6.6
18.2
Wood
70.2
1.5
22.1
* Scale weight (mg)/area of test piece (cm2) after 30 days from test piece setting.
                                           217

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          Table 5.5   Results of Scale Formation of Calcium Carbonate Experiment



                                               (Water temp.: about 13°C pH: about 10.4)
Place putted test place
10cm lower from water surface
of lime sedimentation tank
10cm lower from water surface
of lime sedimentation tank
effluent holding tank
Days passed after test piece putted (D)
o
0.075
0.503
6
0.316
0.645
8
0.347
1.587
10
0.603
4.040
15
1.489
7.695
Scale weight (mg)/area of test piece (cm2)
                                         218

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Table 5.6   Separation Results of Lime Sludge by Centrifuge for Laboratory
                                                          3,000rpm  10 minutes

Results of
analysis
Rate of each
component in
dry sludge (%)
Rate of each
component
captured in
each layer
(%)
Ca (mg/g)
Mg (mg/g)
Fe (mg/g)
P (mg/g)
VSS (mg/g)
Specific gravity
Water content (%)
CaC03
Mg(OH)2
Fe(OH)3
Cas(OH)(P04)3
VSS
The others
Solids
CaC03
Mg(OH)2
Fe(OH)3
Cas (OH)(P04)3
VSS
The others
Feed sludge
255
69.2
3.34
14.4
181
2.250
89.5
60.0
16.6
0.6
7.8
13.0
2.0







Dewatered sludge
Upper layer
167
138
5.58
37.2
284
2.076
89.0
27.1
33.0
1.1
20.1
18.2
-
20.6
9.5
39.0
35.9
51.3
36.2

Medium layer
186
122
5.50
26.9
259
2.093
82.7
32.1
29.2
1.0
14.5
16.9
4.3
14.6
7.9
24.5
23.1
26.2
23.8

Lower layer
313
41.0
1.98
5.17
94.4
2.276
57.4
75.3
9.8
0.4
2.8
6.4
3.3
64.8
82.6
36.5
41.0
22.5
40.0

                                 219

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Table 5.7   Results of the Second Stage Dewatering
           Caracter of the First  Stage Centrate
              SS:   11,800 mg/e          Fe:   20.5 mg/g-dry sludge
              Water  Content:   98.8%     P:    19.7 mg/g-dry sludge
              Ca:   105 mg/g-dry Sludge  VSS:  330 mg/g-dry sludge
              Mg:    132 mg/g-dry Sludge

Dewatering
condition
Results of dewatering
Centrifugal force (G)
. Sludge feed rate (m3/h)
Conveyer revolution (rpm)
Pool depth
Water content (%)
Rate of each component
captured in dewatered sludge
(%)
Solids
Sludge volume
CaC03
Mg(OH)2
Fe(OH)3
Cas(OH)(P04)3
vss
The others
1
1,000
0.917
6
3
81.3
26.1
1.1
81.0
36.6
27.9
32.6
42.6
61.1
2
2,000
0.798
6.7
3
83.3
37.5
2.2
86.6
49.7
42.9
45.2
51.5
66.7
3
3,000
0.822
8.1
3
85.3
40.5
2.7
84.1
57.5
52.1
53.6
60.4
55.6
4
4,000
0.895
9.4
3
84.8
47.3
3.2
87.6
59.3
55.5
55.7
63.9
67.6
                  220

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   6-,
   5.
   4-
|2H
   1-
                   Dissolved Phosphorus in Influent
O 0 minute after pH adjustment




9 90 minutes after pH adjustment





• 180 minutes after pH adjustment




x  Lime treated water
                                                       10
                              11
                                     PH
          Fig. 5.1  pH Lowering vs. Resolublization of Phosphorus
                               -  221 -

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         Centrate
         !  I  I  I I I
         De watered
           / / /
           Sludge/
                       Centrifuge Tube
^ Upper Layer
  Specific Gravity = 2.076
  Medium Layer
  Specific Gravity = 2.093
  Lower Layer
  Specific Gravity = 2.276
Fig. 5.2  Result of Lime Sludge Centrifugal  Separation
                      222

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  100 T
   90-
55
1UU-
80-


g- 60-
^
£ ,A
.3 40-
o
>
20-

/ Upper Layer
/7l
iS
\
\
\
\
\
\
\
\
\
\
:HI










^r- Medium Layer

/• Lower Layer
if
L











j~j
K 1 IrTll,-, n |~|
20
40  ~ 60 ~ 80
(Grain Diameter
                                                                  100
            20    40    60    80   100   12Q   140    160   180  200   220
                                    (Grain Diameter (^))
                       Fig. 5.3   Grain Size Cure of  Each  Layer
                                    223

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100 ,
90
80
70
60
50 C
40
30
20
10
0
i "• — -£ -^ Rate of CaCO3 Captured in Dewatered Sludge
\ Rate of Total Solids
^ *f Captured in Dewatered Sludge
XAI^*^ ^~ Water Content of Dewatered Sludge
_ speed Sludge ^*a5;^— _ _ _^^ A 	 -o—
^°— r""0' ° *~
^ ^" ' Rate of CaCO3 in Dry Dewatcred Sludge
Experiment Condition (A series)
Centrifugal Force: IOOOG
Conveyer Revolution: 6 rpm
Pool Depth: 3
100
90
80
70
60
50
40,
30
20
10
Oi
:^
- ?—*- 	 A A
" /' ^^^^
- /'
. / . o 0
V
k
/ Experiment Condition (B series)
1 Sludge Feed Rate: 0.81 2 r
/ Conveyer Revolution: 6—8 rp
/ Pool Depth: 3
J
      0.4         0.8         1.2         1.6

                 Sludge Feed Rate(m3/n)
                                                      2.0    0         1000        2000

                                                                        Centrifugal Force (G)
                                                                                              3000
 100 -I

  90 -

  80 -

  70

  60

g50

  40
10
                                                     100
                                                     90
                                      X—
                                    Caractcr of Feed Sludge
                                      Water Content:   94.5%
                                      Rate of CaC03 in
                                      Dry Sludge:  '    53.4%
                                                     60-
                                                     40 •
              Experiment Condition (C series)
                Centrifugal Force'     IOOOG
                Sludge Feed Rate.     0.838 -0.923 m3/h 30
                Conveyer Revolution.  6 rpm
                                                     20
                                                     10 •

                                                      0
               1            2           3
         (0.5-0.8mm) (1-1.6mm) (1.5~2.4mm)
                      Pool Depth
                                                                   Experiment Condition (D series)
                                                                      Centrifugal Force:  IOOOG
                                                                      Sludge Feed Rale:  0.838 ~ 0.894 m3/h
                                                                      Pool Depth:        1
                                                        0           S           10
                                                                 Conveyer Revolution (ipm)
Fig. 5.4    Dewatering  Results of Lime Sludge  by  Centrifuge  for Pilot Plant

-------
        -   5
        0
        X
32
DO x
o •—
'' n
x O
"— O
OO co
C/3 O
                                       Cas(OH)(P04)3
                                                CaC03
             12          11          10          9           ;

                                   PH

      Fig. 5.5  pH Reduction and Each Component Change of Lime
               Sludge by Recarbonation
                              225

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0
                                     20
40
60
80
100
[;ced Sudge
(pH = 11.29,SS = 25.3g/2)
Recarbonation Sludge
(pH = 8.11,SS = 16.8g/£)
.
1 '

CaC03





Nv^OH





"ca


1 	
1 	
\=
1 The Others
(JQH)(P04)3


             Fig. 5.6   Rate of Component in Feed Sludge and Recarbonation Sludge
                                          226

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CHAPTER 6.  ADSORPTION  BY  ACTIVATED  CARBON  AND REGENERA-
              TION OF SPENT CARBON
6.1    Adsorption Studies by Granular Activated Carbon	228
  6.1.1   Outline of Experiment Facilities	228
  6.1.2   Conditions of Experiment	228
  6.1.3   Results of Adsorption Experiments	228
6.2    Regeneration of Granular Activated Carbon	     	232
  6.2.1   Introduction	232
  6.2.2   Reactivation by Multi-Hearth Furnace     	     	232
  6.2.3   Arrangement for Experiment	    	      . 232
  6.2.4   Experiments	      	    	234.
  6.2.5   Measuring Items and Methods of Measurement	234
  6.2.6   Regenerating Conditions	      	235
  6.2.7   Results of Regeneration    	    	  ^35
  6.2.8   Summary    	,237
6.3    Laboratory Regeneration Test of Granular Activated Carbon ....    .  ..239
  6.3.1   Introduction	        	239
  6.3.2   Laboratory Equipment Used.   .              ....    	239
  6.3.3   Testing Method	         	239
  6.3.4   Results of Tests	      .240
                                  227

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6.    ADSORPTION  BY  ACTIVATED CARBON  AND REGENERATION  OF
     SPENT CARBON
6.1   ADSORPTION STUDIES  BY  GRANULAR  ACTIVATED  CARBON
6.1.1   OUTLINE OF EXPERIMENT  FACILITIES
     Kyoto Pilot Plant is equipped  with six contact column using granular activat-
ed carbon. They are paired off into  three groups, permitting three tests at the same
time.
     Flow diagram of the process is as illustrated in Fig. 6.1. The dimensions and
other particulars are as follows.
Dimensions:                       surface area, 0.76 m x 0.93 m = 0.7 m2
                                  allowable maximum head loss, 5.0 m
Media support:                     Leopold block, gravel layer (25 cm)
Washing:                          back washing and surface washing in com-
                                  bination
Processing capacity:                maximum overflow rate, 600 m3/m2/d.
                                  (17.5 m3/hr/column)

     The characteristics of activated carbon charged into the column are as listed in
Table 6.1.1.
     The colum  are  so pipe harnessed as  to permit other three running  modes
single-column 6-group, 3-column 2-group, and 6-column 1-group.

6.1.2  CONDITIONS OF  EXPERIMENT
     In  the adsorption experiment, column have been operated for some 12 months
or around  35,000  m3 in terms of  the volume of wastewater passed through  per
0.7 m2  after being charged with fresh carbon and  for some 6 months or 13,000 m3
in the volume of wastewater after regeneration of carbon.
     As regards the fresh carbon, LV 10 m/hr has been taken as standard. As regards
the regenerated carbon, the contact  time has been fixed at 18 min. per column, and
LV has  been  set at around 9.4 m/hr,  a little lower than fresh carbon, to meet  the
decrease of bed depth due to regeneration loss. Wastewater flow in the column is
downward.
     For the adsorption  experiment the filtered secondary effluent obtained from
the Toba Sewage  Treatment  Plant has been used. In filtration,  A12(SO4)3  has
occasionally been dosed at a rate  of about 0.65 — 1.96 mg/1 as Al. There has been
practised no particular flocculation sedimentation  to speak of, so majority influent
for the experiment may be said to  be simply filtered secondary effluent.
     The influent flow down through the column gravitationally, and its SS gradual-
ly blocks up carbon bed, decreasing actual LV
     In  order  to avoid this, the primary column has been put to back washing about
once every  three  days. Backwash flow rate has been  set  at 0.74 to 0.9 m3/m2/min,
though  different  slightly dependent on the columns.

6.1.3  RESULTS OF ADSORPTION  EXPERIMENTS
     The results of experiments so  far conducted show that the adsorption effect
                                    228

-------
is slightly different with the kind of carbon. And the carbons have much in common
from the view point of time-dependent patterns.
     The  discussion here is therefore referred to Brand-A (8  x  30) for the secular
change and  to  the data obtained in  1975 (regenerated carbon)  for the differences
due to difference in quality of carbons.
(1)  Removal of organic matter
     Secular  changes of indices for organic matter  - BODS, CODMn and TOC -
are shown in Figs. 6.2 through 6.4. As is clear from these figures, the organic matter
removal capacity of activated carbon is not so high rather than which we expected.
BOD5 : -
     Removal of ordinary BODS  by fresh carbon is  small. Worse, it sometimes runs
by  contraries;  there  are  many such cases as BODS  becomes  the  worse  by the
adsorption treatment with activated carbon.
     In many cases,  the  effluent  of  the secondary  column has  larger BODS value
than that of the primary column. In the  case of regenerated carbon, the removal
is  about  75% at the beginning of restart. After  one month operation however, it
declines to 30%.
     As regards the  fresh carbon,  BODS  value is larger in the effluent of secondary
column than in the  effluent of the primary column, all the way  from  the beginning
of operation.
     This rise of BOD5 value in the effluent of the secondary column was suspected
to be attributable to the  promotion of nitrification in the bed of activated carbon,
and studies  were made in  this respect accordingly.
     Fig. 6.5 shows  BODS  and forms of nitrogen in  influent and contactor  column
effluents, which are  based on  the data  obtained in May 1975.
     On May 8, BOD5  in the effluent of the secondary column  was smaller than in
the effluent  of  the primary column. On  May 29,  the situation was reversed. BOD5
were  measured  at once  in ordinary method  and in  a special  method in which
nitritying bacterias  were  suppressed.  BODS  by  the former  method  is  named
T-BODS, and that by the latter C-BODS. From Fig. 6.5, the following are noticed.
(A)  The larger the change of NO3-N, the more reasonable the decrease of T-BODS.
     If the change of NO3 -N is small, T-BOD5 is inverted.
(B)  Even when T-BODS  is inverted,  C-BODS  decreases reasonably.

     In additions to these facts, decreae of DO is also noticed. Also, various bacteris
are identified in  the  activated carbon contactor column. Hence, inhabitation  of
nitrifying bacteria in the column  permits  of  no  doubt. It is therefore judged that
the increase  of T-BOD5  is due to  nitrification. In support of this, the  pilot  studies
conducted by the Bureau of Water Works. Tokyo  Metropolitan Government,  for the
production  of  industrial water from wastewater revealed lots  of nitrite-forming
bacteria and nitrate-forming bacteria present  in the effluent of activated  carbon
contactor column.
     In view  of these facts, use of T-BODS  as a characteristic to  provide a guideline
for activated carbon treatment will be disagreed. In order to remove T-BOD5 which
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has been taken up as  an index for organic matter  in the Environmental Water
Quality Standard  and the Effluent Limitations Guidelines in Japan, the treatment
using with activated carbon should be reviewed.
     Both fresh carbon and regenerated carbon show small removal of CODMn  con-
trary to our expectation. Even at the beginning of operation, fresh carbon remain-
ed at the level of 30% in removal with a contact time of 18  min. (primary column
effluent) and about 70% for a contact time of 36 min. These values were reduced
to 25% and 50% respectively  in 1  to 2 months after start-up of operation. The re-
moval thereafter decreased gradually to some 30% even with 36 min. of contact.
     This tendency remained the same after regeneration; Only for 2 to 3  months,
50% or more of removal could be  attained stably. In the experiments, there was no
dramatic drop in CODMn  removal,  and it could not be found whether break-through
was developed or not.
     No direct  measurement of CODMn  adsorption capacity was made as to fresh
carbon, but the following was inferred to be according to TOC isothermal adsorp-
tion before and after activated carbon treatment.
(i)   From  Fig.  6.6, the following equation is derived.
     TOC (mg/fi) = 0.889 x COD (mg/8)  + 1.748                         (1)
     Taking the average effluent TOC as  10 mg/1.
     as suggested by Fig.  6.4,  we obtain COD = 93 mg/1. from Eq. (1).
     Namely, at a TOC concentration of around 10 mg/1.,

     CODMn    9.3
     TOC       10
(ii)  TOC Freundrich line of fresh carbon  in Fig. 6.14 is given by the following
     formula.
     x/M = K.C1/n = 0.006.C1'45                                     (3)
     Hence, at  TOC  10 mg/1.  (This  value  is  over  the  chart-range),  x/M ft
     0.169mg/mgft 169 kg/t.
     From Eq. (2), this is converted into COD as follows.
     169 x  0.93=  157.2 kg/t
(iii)  On the other hand, the total, weight of adsorbed matter, L, can be express-
     ed  by  the flow rate, Q, and CODMn concentration difference between influent
     and effluent of carbon column (Ci — Co) as follows.
     L = 2  (Ci -  Co).Q.At
     Cumulative total volume of water, V,  is  given by the following  formula.

     Thus,  Fig. 6.7 is obtained.
(iv)  With reference to Fig.  6.6, after treating 34000 m3 of filtered secondary ef-
     fluent, fresh carbon removed only  105  kg CODMn in the primary column and
     90  kg  CODMn  in the secondary  column. On the other hand, the adsorption
     capacity per column is calculated from (ii) as follows.
     157.2  kg/t x  0.7 m2 x 3 m x 0.5 t/m3 = 165.1 kg. Namely, the removal is 65%
                                    230

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     in the primary and 55% in the secondary.
     It is therefore considered that this denies  the breakthrough of the activated
     carbon.
(v)  In addition, by backwashing the column, a  great quantity of suspended solids
     and COD is  detected in the backwash wastewater as shown in Figs. 6.8  and
     6.9, showing that the activated carbon bed  serves not only as an adsorber but
     as a  filter. For example, the four measurements conducted in the summer of
     1974 are as  shown in Table 6.2; removal of CODMn in the primary column
     by filtration was 0.034 ~  0.125 kg per  168 m3  of water (0.2 ~  0.74 g/m3)
(vi)  Taking an average CODMn  removal  of 0.43  g/m3, 34,000 m3 releases 14.6 kg
     or 14% of removal by filtration. Namely, the weight ratio of actually adsorbed
     CODMn  to the capacity is no more than 50% even in the primary column.
     For all that  the breakthrough is theoretically denied  as above, why CODMn
removal is extremely low.
     The following may be suspected to  be.
@  CODMn  lacks eligibility for organic  matter index.
<3)  Influent is anomalous in quality.
     As regards @, however, TOC removal is much of a muchness, and should be
deleted. As regards (3), the influent used for the experiments was filtered secondary
effluent of activated sludge process.
     The influent applied to the  activated carbon adsorption process which usually
raises 90% or more efficiency is always put following  to chemical  coagulation,  and
effect  of  the omission of this coagulation process may be a cause. To corroborate
this, we are going to proceed a laboratory experiment. From 1976 on, this will also
be corroborated on a pilot plant scale.
TOC: -
     Like CODMn, TOC removal is also  low and far from our expectation. In  the
case of fresh carbon, the removal is below 50% inclusive of the secondary column
from the  beginning of operation,  which is worse than CODMn  removal.
     In the case of regenerated carbon,  the removal is more than 50% at the  be-
ginning with 36 min. of contact, but is still far less on the whole.  Because we lack
satisfactory data we can not make any analysis like as Fig. 6.7. Just as with CODMn
however, the  breakthrough is unlikely.
     This  low removal will be ascribable  to the peculiarities of the influent employ-
ed.
(2)  ABS  removal
     Application of activated carbon to  water and wastewater  treatment is to re-
move organic matter, deodor, remove colouring matter and also  to remove ABS.
     The  pilot plant experiment discussed here placed emphasis to the  removal of
organic matter, but also handled ABS  removal to some extent. Fig. 6.10 shows an
example.
     In the case of fresh carbon, you can find  lower  removal at the beginning of
operation, fourth month  and eight month.  But  ABS  removal is higher and more
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stable. Comparing with the removal of organic  matter. ABS removal recorded is
around 50% with 18 min. of contact and around 80% with 36 min. of contact. In
the case of regenerated carbon, the removal is even more stable; even after 6 months
from  start, the removal remained 90% with 36  min. of contact. But, the removal
with 18 min. of contact plunges to 40 to 50% from about 5th month, and the break-
through is suspected to be.
     ABS  removal is surprisingly high  compared with other items, and this is not
limited  to this  brand (Brand A), but is  seen common to other brands like as
Fig. 6.11. The  figure shows the results of measurement made 5 and odd months after
start-up operation using regenerated carbon.
6.2  REGENERATION OF  GRANULAR  ACTIVATED  CARBON
6.2.1   INTRODUCTION
     The regeneration is carried out by heating, chemical  extraction, oxidation and
decomposition and biodegradation and  so forth, depending on the kind of activated
carbon, adsorption  conditions and matter  to  be adsorbed.  If liquid-phase adsorp-
tion,  like  as  in  sewage treatment is  practised, the surface  of activated carbon
particles are foued up inversibly and it becomes to be difficult to regenerate.
     For this reason, the thermal regeneration (baking reactivation process) is usual-
ly put to practice. Dealt with here are the findings from the experiment on reactiva-
tion of spent  activated carbon by  multi-hearth furnace.

6.2.2  REACTIVATION  BY MULTI-HEARTH  FURNACE
     The following are the conditions required for the regenerator of spent activated
carbon.
(1)  High thermal efficiency
(2)  Easy control of zone temperature  and atmosphere in drying,  baking and acti-
     vating processes
(3)  Less burning-off in baking and activating stages
(4)  Exposing the surfaces of activated carbon particles with high frequency
(5)  Easy control of detention time to meet degree of adsorbed weight of matter
(6)  Less  susceptibility to mechanical  failure  and wear loss
(7)  High capability of covering a wide range of processing rates
(8)  Easy operation and maintenance
(9)  Established and proven structure  as equipment
     The multi-hearth  furnace employed  for  the experiment  is qualified with re-
spect to the above requirement, and has widely been used.

6.2.3.  ARRANGEMENT  FOR EXPERIMENT
(1)  Specifications  of  principal equipment
     The  experiment  installation is  composed  of  a  furnace, spent carbon  feed
     system, regenerated carbon  withdrawal  system, exhaust gas treatment system
     and a steam generator.
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(i)   Furnace
     Type          :    6-hearths type
     Dimensions    :    750 0 x 1,500 H
     Shaft  drive    :    0.23  - 2.3 rpm, variable,  0.4 kW
     Main materials:    Steel + refractory
     Ancillary      :    Gas burner x  8 units
     equipment

(ii)  Steam generator (packaged boiler)
     Type          :    Low-Pressure type
     Capacity       :    0.5 kg/cm2, 75 kg/hr
     Quantity       :    1 unit
(2)  Arrangement  flow  for Experiment    as per Fig. 6.12.
(i)   Spent carbon feed system
     Spent carbon is withdrawed from the  contact colum in the form of slurry,
     put into a dewatering tank where  it is dewatered roughly, and then is charged
     by the screw conveyor onto the 1st  hearth of the furnace at a constant rate.
     Here the moisture content of the spent carbon is about 45 to 50%.
(ii)  Regeneration  method
     The spent carbon thus fed, which  has a water content of 45 to 50% is heated
     at 250 to 950°C in the  furnace, and is reactivated after passing through drying,
     baking and activating  processes.
     The furnace is equipped with six hearths and its  2nd, 4th,  5th and  6th stages
     are  each equipped with two low-pressure velocity gas burners using propane
     gas as a fuel.
     In  order  to promote the reactivation, the  4th, 5th and  6th stage are each
     equipped with two nozzles supplying steam as an oxidizing gas.
(iii)  Regenerated carbon withdrawal system
     The regenerated carbon is then discharged from the withdrawal chute equipp-
     ed  on the 6th stage  hearth into a quench  tank without being exposed to the
     open air and quenched. The quench tank is always supplied with water to keep
     its  temperature below a specified  level. Then, the regenerated carbon is with-
     drawed from the quench tank in the form of slurry and dewatered in a dewater-
     ing tank.
(iv)  Exhaust gas treatment system
     The exhaust  gas from  the furnace contains stinky gas volatilizing at a low
     temperature in  the drying process, organic  gas developed by decomposition
     in the baking process and reducing gas from the reactivating process.  Also  it
     contains carbon particulates  developed by mechanical grinding in the form of
     dust. In order to completedly burn out stinky gas, decomposed gas, reducting
     gas and sut carbon, an after-heater is located just behind the  furnace.
     The after-heater is held at a temperature of 800 to  850°C, and in it  the ex-
     haust gas  is detained  for about 0.5 to 1.0 sec.
     The exhaust gas treated in the  after-heater is then introduced into a scrubber
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     where it is cooled and moistened to remove dust and oxidizing gas, and then is
     vented to the open air.

6.2.4  EXPERIMENTS
     In  order to investigate reactivating condition for  multi-hearth furnace and
activity  recovery rate, some experiments were proceed using the spent carbon from
the Kyoto pilot plant, and pilot scale furnace in December 1974.
6.2.5  MEASURING  ITEMS AND METHODS OF  MEASUREMENT
(1)  Measuring items
     Three brands of activated carbon. A, B and C, are to  be measured as to the fol
lowing items.
(i)   General characteristics
     Apparent density, Particle size  Hardness number.  Fixed residue, Methylene
     blue  number,  Iodine number, Molasses decolorizing index, Phenol value, ABS
     value
(ii)  Adsorption capacity  for organic matter in water
     TOC Freundrich  isotherms using filtered  secondary effluent
(iii)  Micropore characteristics
     Surface area of micropore per unit carbon weight, mean micropore size, micro-
     pore volume, pore size distribution
(iv)  Weight of adsorbed matter
(2)  Outline of measuring methods especially  used in Japan
(i)   General characteristics
     Phenol value:  —
       According to JWWAK 113 (Japan Water Works Association Standard: Me-
       asuring Method of Powder Carbon for Water Works)
       100 ppb phenol solution is taken as a  control, and the amount of activated
       carbon (ppm) required to reduce it to  a concentration  of 10 ppb is measur-
       ed. This amount is called phenol value.
     ABS  value:  -
       According to JWWAK 113.
       The amount of activated carbon (ppm)  required  to reduce the concentra-
       tion of an ABS (sodium alkyl benzene sulphurnate) solution from 5 ppm to
       0.5 ppm is called ABS value.
(ii)  Adsorption capacity  for organic matter in water
     Filtered  secondary  effluent  was  used for measurement  sampling  from the
     Kyoto Pilot Plant on Dec. 23 and 25, 1974. 0.3% and  0.08% powder carbon
     suspensions were  prepared, and  1.0 ml  and 0.5 ml portions were  taken re-
     spectively and added to 20 ml of control solutions.  The mixtures were shaken
     for 2 hrs and filtered.
     The filtrate was acidified with hydrochloric acid, and dissolved carbon dioxide
     was removed  by  bubbling. Then, TC  was measured with a TOC  analyzer.
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     Change  of liquid volume due to addition of suspension was corrected, and
     Freundrich equation was applied  to  adsorbed weight  and residual TOC con-
     centration for refining the data.
(iii)  Weight ratio of adsorbed matter to fresh carbon
     Dry  sample of spent carbon was taken lOOg into an electric furnace using
     nitrogen gas as atmosphere gas and controlled at 900°C, and was heated for 1.5
     hrs. From the resultant weight reduction, the weight rate of adsorbed matter to
     fresh carbon was calculated using the following formula.
          Weight ratio of adsorbed _ Reduction at 900° C
          matter to fresh carbon        Yield at 900° C
     Components  to  be deposited and  occluded into carbon without volatilization
     during the heat treatment at 900° C for 90 min. were neglected.

6.2.6  REGENERATING CONDITIONS
     The  following are important factors for the  reactivation of spent carbon in
the furnace.
(1)  Hearth temperature and its  distribution
(2)  Detention time  of carbon in the furnace
(3)  Hearth atmosphere
(4)  Feed rate of activating steam and its position of feed
(5)  Loading rate of  carbon
     In the test, the maximum hearth temperature was set at 930°C, and the activat-
ing hearths (4th,  5th  and 6th stage) were all set at  the same temperature.
     The detention time was set  at 30 min. irrespective  of the kind and feed rate
of spent carbon.  In  order to avoid burning off  due  to air leakage, the  furnace
atmosphere was controlled at +2  to +5 mm H2 O throughout the furnace.  O2 % in
each stage was controlled below 0.1% using O2 monitoring meter under any specific
conditions. As regards the feed rate and kind of carbon, the activating stage tem-
perature was  changed  with the apparent density as  a basis which  could  provide the
fastest mean of judging the recovery rate.
     The steam feed was set at 0.6 to 0.9  kg/kg RC; the  fourth stage was supplied
some one third and the sixth stage some two thirds.  The loading rate was  set at 25 to
35 kg/m2 hr.  based on  wet weight of spent carbon. The operating conditions in
regeneration for these spent carbon and consumption rate  of fuel aid, etc. are shown
in Table 6.3.

6.2.7  RESULTS OF REGENERATION
(1)   Recovery rate
     The recovery rate of spent  carbon  can be  expressed in two ways;  one is
gravimetric and the   other volumetric. The problem  involved in  the  gravimetric
recovery  rate is  that  the reduction of  carbon size  due to mechanical and  thermal
effects cannot be taken into account in the evaluation of recovery rate.
     Another problem is the inorganic matter which is  left  after  regeneration. The
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recovery rate  should be the gravimetric  one determined by  the  measurement of
weight before and after regeneration.
     The  volumetric  recovery  rate  (A) is  shown in  Table 6.4.  The gravimetric
recovery rate is shown in Table 6.5. The gravimetric recovery rate might possibly
include errors as water content and weight ratio of adsorbed matter to fresh carbon
for calculation  were  taken at random. By way of reference, volumetric recovery rate
(B) as calculated according to another method is shown in Table 6.6. The test results
showed as high a recovery rate as from 94 to  98%.
(2)  Changes in general characteristics
     The  measurements of general characteristics  of fresh,  spent  and  regenerated
carbon are shown in  Fig. 6.13. The adsorption capacity of spent carbon was degrad-
ed seriously, particularly in the primary column. Table 6.7 shows the results of heat
treatment at 900°C in a nitrogen gas atmosphere. It  is evident from Table 6.7 that
the weight ratio of adsorbed matter to fresh carbon in the primary column is large.
     The  recovery rate given in Fig. 6.13  denotes the value showing the extent of
adsorption capacity with that of fresh carbon taken  as 100.  It is calculated accord-
ing to  the following  formula.
               „,.     adsorption capacity  of regenerated carbon
Recovery rate (%) =  	,  v  ,.	y—	j4—i:	c	x  l °°
                       adsorption capacity of tresh carbon
Here we define the term "adsorption rate" as the weight ratio of adsorbed matter to
the adsorption capacity of fresh carbon. The adsorption rate  on each items obtained
from Fig. 6.13  is shown in Table 6.8.
     As is clear from Table 6.8, ABS value is most largest, followed  by molasses
decoloring index,  and methylene  blue number.  Usually, the higher the adsorption
rate, the worse the recovery. This  is corroborated by the experiment. The apparent
density is reciprocal to the  recovery  rate. It  is therefore conjectured  that  the
increase of the recovery  rate  will reduce  the recovery rate  of apparent density.
(3)  Capacity to adsorb  organic matter in  water
     TOC adsorption capacity was measured using filtered secondary effluent. The
results were adjusted by Freundrich equation as shown in Figs, from 6.14 to 6.16.
1/n and K in Freundrich equation are shown in  Table 6.4. As regards 7 mg/C and 3
mg/e of residual TOC concentration, the recovery  of adsorption capacity was from
73 to 110%.
(4)  Micropore characteristics
     As to various brands, nitrogen gas adsorption curves were determined accord-
ing to a modified Constone-Inkley method  to calculate pore size  distribution,  and
get a relationship  between  10 ~ 300A  micropores and their accumulative volume.
Also, the  relationship between 300A ~ 15ju  micropores and accumulative volume of
micropores was determined using the mercury penetration method.
     Surface  area  of micropore per unit carbon weight, mean micropore size,  and
pore volume of brands are shown  in Table  6.10.  According to the  relationship
between accumulative micropore  volume and pore diameter, the micropore  was
graphically differentiated. Pore size distribution is shown in Figs, from 6.17 to 6.19.
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     The recovery rate  of on surface  area of micropore per unit carbon weight
was  88  ~ 92%, and mean micropore size was increased  2 ~  9% after regeneration.
The  recovery rate of total volume of micropores (0 ~ 15/u) was 96 to 103%. Volume
of micropores of 300A ~ 15/u was recovered 101  to 118%, and that for 0 ~ 300A
was  reduced. In the micropores of 0 ~ 300A, 30  ~ 60A micropore volume was
recovered 102  ~ 114%,  while  12  ~ 30A  micropore volume  and  12A  micropore
volume  were recovered 80 ~ 90%  and 87 ~ 92%,  respectively. In order to assess
the size of matter adsorbed to the activated carbon from Table 6.10 and Fig. 6.17 ~
6.19 pore size-wise volumetric adsorption rates are shown in Table 6.11. Adsorbed
matter accounted for  68.4 ~ 82%  volumetrically of micropores of not exceeding
30A.
     In  the  regeneration experiment, micropores  were reduced both relatively and
absolutely,  and transitional  pores  and macropores  were increased. It is said that
iodine  number  becomes proportional  to the surface area of micropores of larger
than 10A, methylene blue number to that of more than  15A, and molasses decolor-
ing index to that of more than 28A. With reference to Fig. 6.13, this is verified as
the recovery rate of molasses decoloring index is  higher than that of  methylene
blue number and iodine number.
(5)  Results of exhaust gas measurement (Reference)
     Measurements of dust,  SOx, NOx  and odorous index, etc.  at the outlet  of
scrubber of after-heating room are shown in Table  6.11.
     The dry gas flow rate at the outlet of scrubber was 373 Nm3/hr which might
include  a measuring error. Its design value is near actual flow rate of the effluent
gas from after-heating room. Odorous index  of gas at the outlet of scrubber is
seen increased,  which might have  been due to  stripping of  organic compounds
contained in  wastewater because   secondary  effluent was used  for  scrubbing.
Removal of hazardous materials, except NOx was high,  justifying the performance
of the equipment.

6.2.8  SUMMARY
(1)  Regeneration achievements by  characteristics
Apparatus density: —
     As a merkmal  for the regenerative recovery rate, the apparent density which
can easily be assessed  on the spot in a short time was employed, and the recovery
rate  became around 100.
Mean particle size: —
     Brand  A reduced by 3.7%.  Other  brands increased to the contrary. This might
have been attributable to  inorganic matter and deposit carbon. The increment  of
ash content was 0.9% for brand A, and  1.2 to 1.9% for brands B and C.
Harness number: —
     No  remarkable  reduction  of  hardness  number of regenerated  carbon was
noticed.
Methylene blue number, iodine number, molasses decoloring  index, phenol value
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and ABS value: —
    The adsorption rate was highest in ABS value, followed by  methylene blue
number, and molasses decolouring index. The recovery rate was lowest in methylene
blue number, followed by ABS value and iodine number. The molasses decoloring
index recorded the highest  recovery rate, showing 95 to  103%.  Iodine number
is  proportional to surface area  of micropores of 10A  and larger and methylene
blue number is proportional  to  that of 15A and larger.  Generally, the higher the
adsorption rate, the lower the recovery rate.
     But the recovery rate  of  molasses  decoloring index which  showed a high
adsorption rate is high, and the recovery of transitional pore is easy.
Micropore characteristics: —
     From  23  to  35% of the total  micropore volume  of activated  carbon  was
occupied with adsorbed  matter.  Of the total adsorbed matter, 68  to 84% went to
micropores of 30A or smaller. Like as general adsorption characteristics, adsorption
rate of micropore was high, and  the recovery rate was low, accordingly. The micro-
pores of regenerated carbon were reduced  relatively and absolutely, and transitional
pores were increased relatively and absolutely.
     As regards the macropores,  there  was  little  difference between fresh  and
regenerated carbon.
Yield  of regeneration (recovery rate): —
     Volumetric recovery rate (A) was 94 to 97%, and  gravimetric recovery rate
was more than 94%. As the apparent density was taken as a merkmal, the recovery
rate became high.
(2) Comprehensive Evaluation of the Experiment
    As discussed in the  foregoing, the capacity recovery rate of spent  carbon  was
90 to 95%, and the yield was 94 to 97%. The capacity recovery rate is reciprocal to
the yield. It is difficult to judge which we should notice as index capacity recovery
rate  or yield  in  regeneration recycle of carbon. So  long as  the experiment is
concerned, both showed satisfactory results. The regeneration temperature was very
stable. The oxygen gas concentration in the furnace was as low as less than  0.1% on
an O2 monitor, and burning off of activated carbon was not noticed. The running of
the furnace was possible for an extended period under steady state conditions.
under steady state conditions.
     Adsorbed  matter from  the secondary  effluent was  represented by  such as
adsorbed to micropores of less than 30A. Iodine number, methylene blue number
and ABS value should be taken as merkmal for regeneration; however, if their
recovery rate is set at  100% or more, there is a great possibility of getting the yield
reduced. For this reason,  adoption  of methylene blue number which is proportional
to comparatively  large pores out of macropores  and  the apparent density  which
is  proportional to the yield  will be  practically warrantable for the regeneration
purposes.
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 6.3  LABORATORY  REGENERATION  TEST OF  GRANULAR  ACTIVATED
     CARBON
 6.3.1  INTRODUCTION
     Along with the pilot plant scale regeneration experiment discussed under 6.2,
 a laboratory  regeneration  test of spent carbon obtained from Kyoto Pilot Plant
 has been conducted  using a laboratory furnace. The test is still under way, and
 submitted here are the results obtained so far.

 6.3.2  LABORATORY  EQUIPMENT USED
     The regenerating furnace used is a part of a multi-hearths type furnace. It is
 composed  of a  combustion  chamber  and  a  heating chamber  as  illustrated  in
 Fig.  6.20.  The  heating  chamber  is equipped  with an agitator which  permits
 ploughing-up  of sample. The charging  of sample  is accomplished from  the top
 cover, and  the with drawing is carried out from the outlett equipped in the hearth
 bed  while  operating  the agitator. The  performance of the furnace  is as  follows.
     Max.  operating  temperature in  the  bottom  of heating  chamber:   1,100°C
     Effective dimensions of heating chamber:  458 mm 0 x  191 mm H
 The temperature control of the heating chamber is undertaken by two  thermometric
 controllers  equipped  in the chamber and  one  thermometric controller equpped in
 outside  of  the  chamber as well  as  by  combustion burners. Temperatures in the
 furnace  are recorded  automatically.

 6.3.3  TESTING METHOD
 (1)   Sample
     In the test, spent carbon of brand A obtained from Kyoto Pilot Plant was used.
 The spent carbon was completely saturated with water, and 5 lit. were sampled and
 drained for 30 min. In this state the water content was 48 to 51%.
 (2)   Temperature setting
     Atmospheric gas temperature  in the top  zone of the heating chamber were
 set at 500,  600, 700,  800,  900, and 1,000°C.
 (3)   Atmospheric gas for regeneration test
     Character of the atmospheric gas in  the  regenerating furnace was as follows.
           C02 Content              11.6  ~  15  V/V %
           O2   Content             0-1.2
           CO  Content             0 ~  2.3
The  measurement  was  carried out  with an  Orsat gas analyzer. Steam activation
 was not carried out.
(4)   Items  measured
    The measured items are as follows.
     (i)   Apparent density
     (ii)  Iodine  number
    (iii)  Methylene blue number
     All these measurements  were in accordance with JIS K 0102.
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6.3.4   RESULTS OF  TEST
(1)  The apparent  density vs. temperature relationship is shown in Fig. 6.21. The
    apparent density  of regenerated  carbon  was almost the same level as that of
    fresh carbon when an  atmospheric gas temperature were from 500 to 800° C
    but was smaller when an atmospheric gas temperature was above 900° C.
(2)  The iodine number vs.  temperature relationship is shown in Fig. 6.22
    The spent carbon was rejuvenated  at  800°C almost to the level  of fresh
    carbon. With  increase in temperature above 900°C,  iodine number increases
    toward saturation.
(3)  The methylene blue number vs. temperature relation-ship is shown in Fig. 6.23.
    The spent carbon is rejunenate to  the level of fresh carbon at 900°C.
(4)  When  viewed  from the above three indices, the  optimum  atmospheric gas
    temperature is found to be 800° C if steam activation is not carried out.
                                    240

-------
Table 6.1   Contactor Design
Colum
Brand
Name of carbon
Particle size
Bed depth
No. 1
No. 2
A: CALGON SGL 8/30
FILTRASORB 300
8 x 30
No. 3
. No. 4
B: CALGON CAL 12/40
FILTRASORB 400
12 x 40
No. 5
C: TAKEDA
No. 6
SHIRASAGI
W 8/32
8 x 30
3,000m/m
             241

-------
   Table 6.2   CODMn Removal by Filtration Effect of Granular Activated Carbon Contactor.

Jun. 13
Jun. 27
Aug. 7
Nov. 28
Mean

Jun. 13
Jun. 27
Aug. 7
Nov. 28
Mean
No. 1
L
116.6
119.3
55.75
163

A
0.609
0.170
0.175
0.376

B
0.746
0.204
0.448
0.330
0.432
No. 2
L
116.6
119.3
62
163

A
0.154
0.144
0.160
0.256

B
0.189
0.172
0.369
0.224
0.239
No. 3
L
120.25
113.8
55.25
168.5

A
0.455
0.130
0.134
0.389

B
0.541
0.163
0.346
0.330
0.345
No. 4
L
120.25
113.8
55.4
168.5

A
0.118
0.104
0.116
0.185

B
0.140
0.131
0.299
0.157
0.241
No. 5
L
110.6
117.8
55.75
170

A
0.579
0.126
0.162
0.463

B
0.748
0.153
0.415
0.389
0.426
No. 6
L
110.6
117.8
63
170

A
0.155
0.123
0.190
0.225

B
0.200
0.149
0.431
0.189
0.302
Note:   L = Adsorption Run Length
      A = Backwashed COD^n Loading per
       B = Backwashed COD^n Loading per
One Time (kg)
Unit Volume of treated Water (mg/m3)
                                      -  242

-------
                    Table 6.3  Operational Condition of Regenerater
Contactor
Brand of Carbon
Column
Spent Carbon
Total Feed Weight kg WSC
kg DSC
Spent Carbon
kg WSC
kg DSC/Hr
Spent Carbon
Average Moisture wt %
Temperature at each Hearth
Outlet of Exhaust Gas °C
Second Hearth °C
Third Hearth °C
4th Hearth °C
5th Hearth °C
6th Hearth °C
After Heat Room °C
Inlet to Scrubber °C
Outlet of Scrubber °C
Retention Time min
LPG for Fuel Aid
4th Hearth 2/Hr
5th Heartli 2/Hr
6th Hearth £/Hr
Total 2/Hr
Steam Fed
4th Hearth kg/Hr
6th Hearth kg/Hr
Total kg/Hr
Air Supplied m3/Hr (°C)
m3/Hr (°C)
Fuel Consumption 2/Hr
Gas Content CO % (Hearth)
CO2 % (Hearth)
O2 % (Hearth)
No. 1
No. 2
Brand A
Primary
Column
1592.9
960.5
65.5
39.5
39.7
260-300
510-520
540-560
920-930
920-930
920-930
850-870
600-620
70-80
30
1383.6
818.6
959.2
3161.4
9.3
19.8
29.1
(30)
81.35
5.45
3.0(6)
12.2(6)
0.11(1-6)
Secordary
Column
1609.9
931.6
59.3
34.4
42.1
220 -270
410 -420
485 -495
900 -905
900 -90S
900-905
820-860
590-620
50-60
30
1206.0
779.4
846.1
2831.5
11.7
21.3
33.0
(29)
77.68
6.36
3.4(4)
12.0(4)
0.11(1-6)
No. 3
No. 4
Brand B
Primary
Column
1445.4
830.7
58.4
33.6
42.5
250-280
450-455
500~510
910-920
910-920
910-920
850-860
620-640
50
30
1198.6
893.0
772.7
2864.3
10.9
20.0
30.9
(32)
76.45
6.22
2.4(4)
12.1(4)
0.11(1-6)
Secordary
Column
1553.1
852.7
58.4
32.1
45.1
240
390 -400
450-460
880
880
880
830-840
620
50
30
1091.0
753.1
687.6
2531.7
9.9
20.3
30.2
(28)
71.35
7.07
2.8(6)
12.2(6)
0.11(1-6)
No. 5
No. 6
Brand C
Primary
Column
1674.4
961.4
62.0
35.6
42.6
250-265
450-460
495-510
905-915
905-915
905-915
820—840
600-620
50
30
1177.0
842.8
726.1
2745.1
10.4
20.6
31.0
(32)
76.89
6.0
2.0(2)
12.1(2)
0.11(1-6)
Secordary
Column
1657.1
947.5
59.5
34.0
42.8
220 -240
420 —430
510-520
890 -900
890 -900
890 -900
820 —860
580 -630
60-70
30
1182.1
775.5
623.4
2581.0
9.7
19.7
29.4
(30)
71.85
6.88
2.8(6)
12.1(6)
0.11(1-6)
(Note) WSC = Wet Spent Carbon  DSC = Dry Spent Carbon
                                       -  243  -

-------
Table 6.4   Volumetric Recovery Rate (A)
Column No.
Bed depth before regeneration
mm
Bed volume before regener-
ation m3
Bed depth after regeneration
mm
Bed volume after regeneration
m3
Volumetric recovery rate
%
No. 1
2,902
2.03
2,777
1.94
95.6
No. 2
2,897
2.03
2,723
1.91
94.1
No. 3
2,744
1.92
2,670
1.87
97.4
No. 4
2,897
2.03
2,732
1.91
94.1
No. 5
3,024
2.12
2,905
2.03
95.8
No. 6
2,895
2.03
2,782
1.95
96.1
              -  244

-------
Table 6.5  Gravimetric Recovery Rate
Column No.
Wet weight of spent car-
bon (A) kg
Mean moisture of spent
carbon (B) %
Weight ratio of adsorbed
matter to carbon (C) %
Dry weight of spent
carbon (D) kg
Wet weight of regenerated
carbon kg
Average moisture of regenerated
carbon %
Dry weight of regenerated
carbon kg
Gravimetric recovery rate
%
No. 1
1,592.9
39.7
0.149
836.0
1,370.6
41.3
804.1
96.2
No. 2
1,609.9
42.1
0.114
836.7
1,390.6
43.4
786.5
94.0
No. 3
1,445.4
42.5
0.193
696.7
1,271
43.9
712.7
102.3
No. 4
1,553.1
45.1
0.172
727.5
1,286.1
44.5
713.8
98.1
No. 5
1,674.4
42.6
0.188
809.0
1,422.0
43.0
811.3
100.2
No. 6
1,657.1
42.8
0.134
835.9
1,424.2
43.1
810.9
97.0
     D = A • (1 -
                 100    1 +C
                -  245 -

-------
Table 6.6   Volumetric Recovery Rate (B)
Column No.
Dry weight of spent carbon
kg
Apparent density of spent
carbon
Volume of spent carbon
m3
Dry weight of regenerated
carbon kg
Apparent density of regener-
ator carbon
Volume of regenerated carbon
m3
Gravitational recovery rate
%
No. 1
960.5
575
1.67
804.1
485
1.66
99.3
No. 2
931.6
552
1.69
786.5
485
1.62
96.1
No. 3
830.7
565
1.47
712.7
450
1.58
107.7
No. 4
852.7
528
1.61
713.8
450
1.59
98.2
No. 5
961.4
570
1.69
811.3
482
1.68
99.8
No. 6
847.5
555
1.71
810.9
482
1.68
98.5
                   246  -

-------
Table 6.7  The Result of Heat Treatment in 900°C Nitrogen Gas
•^^
Items
— — ^___^ Brand
•- ~~- —
^^~-\^^ Column
Bed density, backwashed and
drained of spent carbon
Iodine number of spent
carbon
In 900° C
Nitrogen
Gas
After heat
treatment
Recovery rate after
90 min. treatment
Weight ratio of ad-
sorbed matter to
fresh carbon
Recovery rate (%)
Apparent density
Iodine number after heat
treatment
A
No. 1
575
0.68
87.0
0.149
94
512
0.93
No. 2
552
0.73
89.7
0.114
96
500
0.95
B
No. 3
565
0.67
83.8
0.193
92
486
0.96
No. 4
528
0.74
85.3
0.172
96
467
0.99
C
No. 5
570
0.67
84.2
0.188
102
485
0.93
No. 6
555
0.73
88.2
0.134
99
500
0.95
                            247

-------
Table 6.8   Adsorption Rate to the Capacities
Column
Apparent density %
Methylene blue number %
Iodine number %
Molasses decolorizing index %
Phenol value %
ABS value %
No. 1
19.5
52.9
28.4
55.1
34.2
62.5
No. 2
14.8
29.4
23.2
44.3
-
-
No. 3
25.8
60.0
33.0
57.0
39.5
70.0
No. 4
17.6
35.0
26.0
41.8
3.7
-
No. 5
14.9
55.6
29.5
53.5
39.5
68.1
No. 6
11.9
33.3
23.2
39.8
-
-
                -  248 -

-------
Table 6.9  Constants in Freundrich Equation and Recovery Rates
Brand
Fresh carbon
Spent carbon*
Regenerated carbon
Comparison of ad-
sorption capacity at
7 ing/2 TOC level
Comparison of ad-
sorption capacity at
3 mg/2 TOC level
1/n
K
1/n
K
1/n
K
Fresh carbon
Regenerated carbon
Recovery rate
Fresh carbon
Regenerated carbon
Recovery rate
Brand A
1.45
0.006
1.75
0.0005
1.0
0.011
0.094
0.072
76
0.028
0.031
111
Brand B
1.4
0.006
1.75
0.0004
1.1
0.010
0.100
0.084
84
0.029
0.033
114
Brand C
1.4
0.007
1.7
0.0005
1.05
0.010
0.099
0.073
73
0.030
0.030
100
* The spent carbons are from Primary column
                              249

-------
Table 6.10  Micropore Characteristic of Each Carbons

Surface Area
m2/g
Mean Diameter
of Micropore A
Volume of
Micropore cc/g
0~15;U
Volume of
Micropore
30dA~15;U
Volume of
Micropore
-300&
Volume of
Micropore
30 ~ 60A
Volume of
Micropore
12-30&
Volume of
Micropore
~12A
Brand A
Fresh
Carbon
980
20.5
0.820
0.317
0.503
0.058
0.176
0.205
Spent
Carbon
No. 1
495
22.5
0.535
0.257
0.278
0.039
0.082
0.104
No. 2
610
22.5
0.629
0.285
0.344
0.044
0.111
0.119
Re gen
Car
905
22.4
0.825
0.319
0.506
0.063
0.163
0.185
erated
son
Recov-
ery
Rate
92
-
101
101
101
108
93
90
Brand B
Fresh
Carbon
1065
21.8
0.901
0.321
0.580
0.065
0.218
0.206
Spent
Carbon
No. 3
470
24.0
0.553
0.271
0.282
0.043
0.092
0.080
No. 4
590
22.0
0.610
0.282
0.328
0.043
0.109
0.111
Regen
Cart
935
22.4
0.866
0.343
0.523
0.074
0.177
0.180
srated
>on
Recov-
ery
Rate
88
-
96
107
90
114
81
87
Brand C
Fresh
Carbon
970
20.6
0.787
0.287
0.500
0.054
0.163
0.216
Spent
Carbon
No. 5
500
22.0
0.537
0.263
0.274
0.037
0.088
0.086
No. 6
580
22.1
0.594
0.274
0.320
0.040
0.107
0.126
Regen
Carl
850
22.0
0.808
0.340
0.468
0.055
0.131
0.198
srated
jon
Recov-
ery
Rate
88
-
103
118
89
102
80
92

-------
Table 6.11  Distribution of Absorbed Matter along with Pore Size
Column
Total micropores volume
0 ~ 15jU cc/g
Reduction of micropores
volume % 0 ~ 1 5ju
Reduction of micropores
Volume % 300A~15jU
Reduction of micropores
Volume % ~ 300A
Reduction of micropores
Volume % 60 ~ 300A
Reduction of micropores
volume % 30 ~ 60A
Reduction of micropores
volume % 12 -30 A
Reduction of micropores
volume % ~ 12A
No. 1
0.535
34.8
21.1
78.9
3.8
6.7
33.0
35.4
No. 2
0.629
23.3
16.8
83.2
—
7.3
34.0
45.0
No. 3
0.553
38.6
14.4
85.6
6.9
6.3
36.2
36.2
No. 4
0.610
32.3
13.4
86.6
8.9
7.6
37.5
32.6
No. 5
0.537
32.8
9.6
90.4
1.6
6.8
30.0
52.0
No. 6
0.594
24.5
6.7
93.3
10.4
7.3
29.0
46.6
                             -  251 -

-------
Table 6.12  Determination of Exhausted Gas from the Furnace
^-^^^ Position
Items ^^^~~^^^
Temperature of gas
Dry gas flow
Moisture
Soot
S02
NO
NOX
Odor PO
C02
02
°C
Nm3/H
Vol%
g/Nm3
ppm
ppm
ppm
-
Vol%
Vol%
Outlet of
furnace
240
69
42.4
1.31
3
62-74
65-76
11.9
10.9
3.3
Outlet of
after heat-
ing room
620
675
22.5
0.16
235 ~ 240
100- 110
105- 115
2-.6
11.4
4.0
Outlet
scrubber
40
373
2.4
0.05
6-9
113- 123
118- 128
5.3
8.3
8.6
Method used for
analysis
TC-Thermometer
JIS Z-8808
JIS Z-8808
JIS Z-8808
.JISK-0103
JISK-0104
Equilibrium method
with salt water
Orsat Analyzing
method
                          252

-------
Mark
CT
S

MT-1
MT-2
HF
P-l
P.2
P.3

Equipments
Carbon ConUclor
Intermediate PW Holding
Tank
FMT for PW
FMT for BWW
FW Sample Hold ing Tank
Feed Pump
Intetmediate Feed Pump
Pump for BW

Mark
P-4
SP-]

SP-2
V-l
V-2
V-3
V-4
V-5

Equipments
Pump fot SW
Sampling Pumps for FW

Sampling Pumps for PW
Valves for FW
Valves for PW
Valves for BW
Valves for SW
Valves for Headloss flage,
WS
Mark
V-6
P-5

P-6
Sol-]
Sol.2
Lsw.l
Lsw-2
Uw-3

Equipments
Valves for BWW
Pump for BWW Dram

Handing Water Pump
Solenoid Samplers
Solenoid Samplers
WLS for CT
WLS for S
WLS for FW Holding
Tank
Mark
Lsw^
Fi-1

Fi-2
Fu-1
Fu-2
Fi-3
Fu.3
Lsw-S

Equipments
WLS for PW Holding Tank
Fl for BW

FlforSW
FS for BW
FSforSW
FllbrFW
FSforFW
WLS for Drain Pil.

(Abbreviations)   FW: Feed Waler, PW: Carbon Product.   BW: Backwash Water, SW: Surface-wash Water,  BWW: Backwash Waste Water,
              FMT; Row Measuring Tank, WLS. Water Level Switch, FI: Flow Indicator, FS. Flow Meter Senser.
                      Fig.  6.1    Flow Chart of  Carbon Contactor

-------
 Start
Q
O
CQ
                          -No. 2 Eff.
                          Secondary Column
         Fig. 6.2 (a)   BOD Adsorption by Granular Activated Carbon of Column No. 1 and No. 2

-------
cn
Cn
                                                                                                                                   No. 1 Int.
                                                                                                                             —•—  No. 1 Eff
                                                                                                                            — A—  No. 2 Eff,
                                       -f	'	'	'	—i	1	r	—	  —'"i
                               APR.            MAY             JUN.            JUL.               AUG.           SEP.
                                                                                      1974
                                          Fig.  6.2 (b)   BOD Adsorption by Granular Activated Carbon of Column No. 1 and No. 2
OCT.
                NOV.

-------
to
Ln
                                       JAN.
                                                     FEB.
                                      Fig. 6.2 (c)   BOD Adsorption by Granular Activated Carbon of Column No. 1 and No. 2

-------
en
--J
                                     "SB
                                      c
                                     Q
                                     a
                                                           No.l Inf.
                                                           No.l Eff
                                                      »— No.2 Eff
                                          10
                                                   NOV.
                                                             1973
                                        Fig. 6.3 (a)  COD|\/|n Adsorption by Granular Activated Carbon of Column No. 1 and No. 2

-------
1NJ
tn
cc
Q
O
U
                                                                         No. I Inf.

                                                                         No. 1 Eff

                                                                  — A--  No. 2 Eff
              10
                        APR.
                                                                                                                   OCT.
                                                                                                                                            NOV.
                                         Fig. 6.3 (b)   CODMn Adsorption by Granular Activated Carbon of Column No. 1 and No. 2

-------
en

UD
                           o.
                           o
                                      JAN.
                                                   FEE
                                                                           1975
                                        Fig. 6.3 (c)  COD|y/|n Adsorption by Granular Activated Carbon of Column No. 1 and No. 2

-------
 Start
o
              NOV.            DEC.
                     1973
JAN.
FEB.     '      MAR.
       1974
          Fig. 6.4 (a)  TOC Adsorption by Granular Activated Carbon of Column No.1  and No. 2

-------
APR.
                                                                                    OCT.
                                                                                                 NOV.
       Fig. 6.4 (b)  TOC Adsorption by Granular Activated Carbon of Column No. 1 and No. 2

-------
                                                                                     No.l Int
                                                                                     No.l f.ff
                                                                              - + - No.2 Bff
JAN.
              FEB.
                                                            MAY
                                                                           JUN.
                             MAR.           APR.
                                       1975
Fig. 6.4 (c)   TOC Adsorption by Granular Activated Carbon of Colum No. 1 and  No. 2
                                                                                         JUL.

-------
mg/S
K
i n
5-
0



17.9
==?





MAY 8












«



T
C


BOD;
BOD5
























         Inf.  No.l  No.2
              Eff.  Eff.
 mg/S
  20
   10-
 No.3   No.4
 Eff.   Eff.

MAY 8
         Inf.  No.l  No.2
              Eff.   Eff.
No.3  No.4
 Eff.   Eff.
                                                          10-
                                                                                             MAY 19
No.5  No.6
 Eff.   Eff.
            mg/e
                                                        20
                                                         10-
                   Inf.   No.l   No.2
                        Eff.   Eff.

                        IIIIHI! 0-N
         No.3  No.4
          Eff.   Eff.
                              No.5  No.6
                              Eff.   Eff.
                                                                                              N02-N
                                                                         NH4-N
                                                                                MAY 19
No.5
Eff.
      No.6
      Eff.
                                                              Inf.
No.l
Eff.
No.2
Eff.
No.3
 Eff.
No.4
 Eff.
No.5  No.6
Eff.   Eff.
                  Fig. 6.5   Effect of Nitrification in Contactor on Effluent BOD5
                                                   -  263  -

-------
Fig. 6.6  Corelation between CODMn  and TOC
                264

-------
   100
Q
P.  50
                              5000
                                                         10000

                                            Quantity of Treated Wastewater
                                                                                   15000
                                                                                                 17500m3
                                                                 Fresh Carbon of No. 1 Column

                                                                 Fresh Carbon of No. 2 Column

                                                                 Regenerated Carbon of No. 1 Column

                                                                 Regenerated Carbon of No. 2 Column
     17500
                 20000
                                                                      30000
                                          25000

                                       Quantity of Treated Wastewater

            Fig. 6.7  Accumulative COD(\/|n Adsorption Curve of Column IMo.1 and No.2
                                                                                                35000m3
                                                265

-------
    220
    200
                                                                          Nov. 28, 1974
00
e^

§.
'o

-d
3
GO
             1     2     3
10    11    12  (Min)
                                        Backwashing Time

                         Fig. 6.8  SS Variations of Backwash Wastewater

-------
to
                                                                                                    Column
                                                                                                    Column
                                                                                                  -  Column
                                                                                                  -  Column
                                                                                                  -  Column
                                                                                                  -  Column
                                                                                        9     10    11    12 (Min)
                                                      Fig. 6.9  CODMn Variations of Backwash Wastewater

-------
                                      Start
INJ
ON
oc
                                                  NOV.     '      DEC.

                                                        1973
JAN.
               FEB.

              1974
                             MAR.
                                     Fig. 6.10 (a)  ABS Adsorption by Granular Activated Carbon of Column IMo. 1 and No. 2

-------
ON
                           0.5
                           0.2
                           0.1
                                    APR.
                                                  MAY.
                                                                JUN.
                                                                                JUL.
                                                                                             AUG.
                                                                                                             SEP.
                                                                                                                          OCT.
                                                                                                                                        NOV.
                                                                                        1974
                                         Fig. 6.10 (b)   ABS Adsorption by Granular Activated Carbon of Column No. 1 and No. 2

-------
    Re Start
0.
0.\
        JAN.
    FEB.            MAR.            APR.             MAY      '      JUN.




Fig. 6.10 (c)   ABS Adsorption by Granular Activated Carbon of Column No. 1 and No. 2
JUL.

-------
                                  APR. 1         mg/e


                                     BODS
 20-
                                                    20-
 10-
                                                    10-
      Inf.   No.l   No.2
           Eff.   Eff.
No.3  No.4
Eff.   Eff.
No.5  No.6
Eff.   Eff.
20
10-
                                   APR. 1
                                    TOC
                                                   0.5
                                                 - 0.4
                                                   0.3
                                                   0.2
                                                   0.1
     Inf.  No.l  No.2
           Eff.  Erf.
No.3  No.4
 Eff.  Eff.
No.5  No.6
Eff.   Eff.
                                                        APR.  1


                                                          CODMll
     No.l  No.2
     Eff.   Eff.
No.3  No.4
 Eff.  Eff.
No.5 No.6
 Eff.  Eff.
                                                               APR. 1
                                                               ABS
Inf.  No.l  No.2
     Eff.   Eff.
No.3  No.4
Eff.   Eff.
No.5  No.6
Eff.   Eff.
             Fig.  6.11   Comparison of Adsorption Effect with Change of Items and Brands
                                             -  271  -

-------
Ji
                                     —t
A

A
A

Meter "-
^
^
^
\fatclr
  I	.
   -P
                                         I  t
   ' i
M
 I  I I
                                                                          •t
                                                                        Water
                                                                        9
                                                                          L
                                                                                              r
                                                                                         Ml  \
                                                                                                      >-

                                                                                                       Water
                                                                     -J
                                                                                                          ICJMl
                                                                                                                      Atmosphere
       l'-l     Fuel Gas
       SC-1   Screw Conveyer
       RF-1   Regeneration Furnace
       OP-1   Oil Pump
    A-l  Exhaust Gas Furnace
    D-l  Scrubber
    S-l   Chimney
    B-l   Boiler
            T-l   Quench Tank
            T-2   Seal Tank
            T-3   Dewatering Tank
            F-l   Exhasted Gas Fan
CP-1  Recycle Pump
                                            Fig. 6.12  Flow Diagram of the Regeneration System

-------
500-
 m2/g
  109
  50-
        Back Washed Bed Density
                       A:  99%
                       B: 100%
                       C: 103%
                        •A
                        D
             i   Fresh Carbon
             ii   Spent Carbon of Primary Column
             iii  Spent Carbon of Secondary Column
             iv  Regenerated Carbon
Methylene Blue Namber
  Recovery Rate A: 94%
              B: 95%
              C:
                                                    50-
  0

mg/i!




 50 -
                                                                 Molasses Decolorizing Number
                                                                     Phenol Value
                                                                        A: 93%
                                                                        B: 96%
                                                                        C: 93%
                                                                                                I
                                                                                              iv
100 .
Iodine Number
  A: 93%
  B: 94%
  C: 94%
                                                   mg/C
                                                    100-
                    Fig. 6.13   Effect of Regeneration on Some  Evaluation Items
                                             -  273  -

-------
Fig. 6
0.1
0.08
0.06
0.04
0.03
0.02
0.01
14 TOC Freundrich Line of Brand A Carbon

















//
/







/






^
s.y
%







/
/




'

_Y

/

/•"




1



&



(


/






{









B







/
/


    \           2      3    456789 10
                  Equilibrium TOC (mg/C)
Fig. 6.15  TOC Freundrich Line of Brand B Carbon
 O.I
 0.08

 0.06


 0.04

 0.03
 0.01
4&
                                   P
     1
                       3    456789 10
                  Equilibrium TOC (mg/C)
Fig. 6.16  TOC Freundrich Line of Brand C Carbon
                       3    4   5678910
                   Equilibrium TOC (mg/C)
                                                      20

n c\%

0 06

n n4
oo
^003
n n^
0 01









/









[/





c
^







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4('






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^
^




/

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^
^j-,





y








c.
4









3

                         274

-------
0.9

0.8
                                 Fresh Carbon
      0.6
                                       Spent Carbon in Secondary Column
o
o
                                            Spent Carbon in Primary Column
      0.4
>
      0.2
          1.0
                                                                       3.0
                                                                                                      4.0
                                                                                                                                     5.0
                                                            logD  [A]
          10
                         50
102
5-102     103
 Diameter of Micropore D [A]
5-103    104
                                                                                                                            5-104    10s
                                                   Fig. 6.17 Pore Size Distribution of Brand A Carbon

-------
^    0.4  -
 Q
  DO
     0.2  -
                           Fresh Carbon
                             Regenerated Carbon
                                  Spent Carbon in Primary Column
                                    Spent Carbon in Secondary Column
         1.0
          2.0
                                                                      3.0
                                                                        4.0
                                                                                            5.0
                                                          logD[A]
                   1     1    \     1 _l — 1 — L
        10
50
102
5-102     103                  5-103
Diameter of Micropore D [A]
104
5-10'     10s
                                              Fig. 6.18  Pore Size Distribution of Brand B Carbon

-------
     0.9
     0.8
t    0.6
Q-
O
>
     0.4
     0.2
 _0
 
-------
                                                    To Chimney
oo
~-J
CO
                                                                         Fan
/V^^
                                                              Steam Inlet
                                                                / Sand Seal
                                                             n !j~'      / Gas Sampler
                                                              In	
                                                               Jl
                                                                       -t
  Heating Chamber
[T- ^      Arm and Teeth
                                                                               Combustion Chamber
                                                                                          Main Burner
                                                                                                              Blower
                                                                                                                            Fuel Pump
                                                                              [Cooling Water]
                                                                              Fig. 6.20   Flow Diagram of Laboratory Furnace
                                                                                                                                                        Fuel Tank

-------
    0.6
                                                                        Spent Carbon
    0.5
-a   0-4  -
                                 o
Spent Carbon
     0.3  -
     0.2
                    500         600          700         800          900



                                          Regenerating Temperature (°C)
         1000
                     Fig. 6.21   Regenerating Temperature and Apparent Density

-------
        (mg/g)
   lOOOh
   900
   800
   700
c
3

z
•
o
                        Fresh Carbon
Spent Carbon
   600
           500          600        700         800        900



                               Regenerating Temperature (°C)





                Fig. 6.22 Regenerating Temperature and Iodine Number
                                               1000
                                  -  280 -

-------
   200
        (m£/g)
S
3
J3

CO

o
c
   100
                     Fresh Carbon
                         Spent Carbon
                                                 J_
            500
600        700         800         900


       Regenerating Temperature (°C)
1000
                Fig. 6.23  Regenerating Temperature and Methylene Blue Number
                                    281

-------
CHAPTER 7.  AMMONIA REMOVAL BY  BREAKPOINT CHLORINATION
              PROCESS
7.1   Introduction     .        	283
7.2   Laboratory Tests	      	283
  7.2.1   Breakpoint Chlorination of Secondary Effluent	283
  7.2.2   Effect of pH on Breakpoint Chlorination	284
7.3   Pilot Plant Experiment on Breakpoint Chlorination	    	285
  7.3.1   Outline of the Pilot Plant	285
  7.3.2   Results of Operation	285
  7.3.3   Troubles over Operation and Performance . .     	286
7.4   Future Research	286
                                 - 282  -

-------
7.   AMMONIA REMOVAL BY  BREAKPOINT CHLORINATION PROCESS
7.1  INTRODUCTION
     The breakpoint chlorination process has been practised as a prechlorination
treatment at water  treatment, plants  receiving water from polluted  rivers. The
control of prechlorination process for water treatment is usually made by measuring
residual chlorine. The breakpoint chlorination process for the removal of ammonia
nitrogen in  sewage  differs  slightly  from the  prechlorination  process for  water
treatment as follows.
1)   Ammonia concentration in sewage varies greatly with time.
2)   It is desirable to minimize residual chlorine in chlorinated effluent.
3)   The effluent to be discharged into receiving waters must not contain residual
     chlorine.

     Now, a pilot plant of breakpoint chlorination  process is operated at the Toba
Sewage Treatment Plant in Kyoto. This report deals with the results of laboratory
tests to determine factors  for the pilot plant installations and an outline of the pilot
plant.

7.2  LABORATORY TESTS
7.2.1  BREAKPOINT  CHLORINATION OF SECONDARY EFFLUENT
     The experiments were  conducted in a batch system using chlorine water and
sodium hypochlorite as the chlorinating agents.
     The summary of the results is as follows.
1)   Chlorination of the effluent with chlorine water reduces pH, and it is necessary
     to use alkali for pH elevation. If sodium hydroxide is taken up for pH control,
     its dose rate should  be 1.0 to 1.5 times  of the chlorine dose rate, in weight
     ratio,  in  order to  raise pH up to  neutral.  Chlorination  with  sodium
     hypochlorite does not require pH control.
2)   Breakpoint chlorination  is  greatly affected   by  pH.  For  the purpose  of
     optimizing the chlorination, pH must be kept in the range of 7 to 8.
3)   The reaction  is considered  to  be  completed within  5 min.  after  chlorine
     injection.  In the  event that  pH after chlorine dose remains low, the  reaction
     can be promoted further by raising pH elevated near the neutral.
4)   Temperature has little effect on reaction.
5)   The breakpoint of the secondary  effluent is  around the  10:1 Wt.  ratio  of
     C1:NH3-N. C1:N ratios of the breakpoint are essentially the same for both
     chlorine water  and sodium hypochlorite. Hence, it is necessary to dose about
     10 mg/1 of available chlorine as Cl in order  to oxidize 1  mg/1 of ammonia
     nitrogen in the secondary effluent.
6)   Nitrate  is formed by Chlorination.  With the increase in Cl/N ratio, the amount
     of nitrate increases, but remains within 1 mg/1.
7)   The color sometimes  develops by chlorine dose above the breakpoint depend-
     ing upon water  quality. This  might be  ascribable to oxidation of iron or man-
     ganese contained in the secondary effluent.
                                    - 283  -

-------
7-2-2   EFFECT OF pH ON  BREAKPOINT CHLORINATION
    The mechanism of the breakpoint chlorination has not been fully understood.
Nevertheless, it is believed that the most important factor affecting the chlorination
is  pH.  Samples  used in  this  senes of experiments  were  distilled water  with
ammonium chloride  and  sodium carbonate.  Sodium carbonate was  added to the
sample to increase  buffer  capacity.  The experiments were conducted in  a batch
system using sodium hypochlorite as a chlorinating agent. Figs. 7.1 and 7.2 show the
results of chlorination with Cl/N ratio adjusted  at 8. The initial pH of the buffer
solution of ammonium chloride was controlled in the range of 5 to 10.
From these experiments, the following were disclosed.
1)  The development of breakpoint in the  sample varies with the initial value of
    pH. Judging from the formation of chloramines, it can be classified into three
    groups acconding to initial values of pH;(5,6), (7,8,9) and (10).
2)  pH  in the sample  varied before and after  chlorination. The two initial pH
    groups of (5,6) and (10) showed a rise in pH after chlorination, while the group
    (7,8,9) showed a drop.
3)  The product in the  group  (5,6) was mainly dichloramine.  The formation of
    monochloramine was not significant. The products from the group (7,8,9) were
    monochloramine and  dichloramine  in  coexistence in  nearly the  same
     concentration.  In the group (10), monochloramine alone was present.

    It was found that there was a difference in the location of breakpoint among
the three groups. Figs. 7.3  and 7.4 show the results obtained  by chlorination with
Cl/N  ratio being changed.  The initial pH value of each  sample was  set at 4.5, 7.5
and 10.2, respectively. The results are summarized below.
1)  At pH 10.2, no clear breakpoint was found.
    At initial values of 7.5 and 4.5, the breakpoints  were around 8  and 9 in terms
    of Cl/N wt. ratio, respectively. The removals of NH3-N at the breakpoint were
    97% and 93%, respectively.
2)  The main product  at  an initial  pH value of 7.5 was monochloramine,  but
     smaller amount of dichloramine was formed. At  an initial pH value of 4.5, the
     main product  changed from monochloramine to dichloramine  as Cl/N  ratio
     increased. At an initial value of pH 10.2, monochloramine alone was detected.
3)  Formation of (NO2 +  NO3)-N after chlorination was barely seen at initial pH
     of 10.2. At  pH 7.5 and 4.5, however,  the formation progressed greatly when
     chlorine  dosage  exceeded  the breakpoint.  The concentrations of (NO2 +
    NO3)-N  at initial values of pH 7.5 and 4.5 were  0.20  mg/1 and 0.42 mg/1,
    respectively at the breakpoint.
4)  At initial  value of pH 7.5, the pH after  chlorination decreased slightly around
    the breakpoint.  At the breakpoint for initial pH  4.5, a sharp decline of pH was
    noticed during chlorination.  Fig. 7.5 shows the  chlorination of a ammonium
    chloride  solution without buffer agent.  It is evident from the figure that even
    if the initial pH is  around 7,  pH reduces considerably unless buffer action is
                                  - 284

-------
given.

7.3  PILOT PLANT EXPERIMENT ON BREAKPOINT CHLORINATION
7.3.1  OUTLINE OF THE PILOT PLANT
     A pilot treatment facility for the breakpoint chlorination process was installed
in the Toba Sewage Treatment Plant, Kyoto, and is now in operation.
     Fig. 7.6 shows a  flow diagram and control system of the pilot facility. In this
facility, ammonia in the sewage is measured by an automatic ammonia analyzer.  As
a  chlorine  source, sodium  hypochlorite solution containing abrut 15% (W/V) of
available chlorine as  Cl, which is  on  market is used.  The dose rate of sodium
hypochlorite is calculated by the following formula. Dose rate (ml/min) = NH3-N
(mg/1) x inflow rate of sewage (m3/d.) x Cl/n ratio - (NaOCl concentration (W/V%)
x  1(T2) H (24 (hrs) x 60 (min)).  As  aninflow to  the  process, filtered secondary
effluent or  effluent  from  activated carbon  contactors  is used.  The maximum
capacity of the facility is designed at 250 m3 /day.
     The facility is currently being run with  the constant flow rate  regulated  by
valve control. At  the maximum  design flow rate, the  detention  time of each
chlorination tank is about 5  min. At present,  C1/NH3-N ratio is manually set. Two
automatic ammonia analyzers-colorimetric type and electrode type-are installed in
order to investigate their performances as well. Each type has a measuring range of 0
to 20 mg/1. For the control  purposes,  one of the two analyzers is employed. The
automated   colorimetric  analyzer  is  divided  into  two   portions;  filtering and
colorimetering.  The filtering portion provides disinfection by heat and filtration of
the sample. This analyzing  instrument  takes roughly 45  min.  from sampling to
measurement.  On the other  hand, the electrode type instrument requires about 20
min. for measurement.  The dosing pump for sodium hypochlorite controls flow rate
by adjusting the stroke and revolutions, and is able to control the dose rate in the
range of 30 to 600 ml/min.
     A test for treating the breakpoint chlorination effluent by a  carbon contactor
just started from September  of this year.

7.3.2  RESULTS OF  OPERATION
     Table  7.1 and 7.2 show  some  of the results of the operation of the pilot plant.
Table 7.1 shows the operating conditions and  ammonia nitrogen concentration over
a period from May  16  to 22. From this table, the followings are found.
1)   The average NH3-N concentrations of the influent and the effluent Were 8.42
     mg/1 and 1.10 mg/1, respectively. Therefore, the average removal of ammonia
     nitrogen was 86.9%.
2)   The concentration of  available  chlorine  in NaOCl solution  decreases a  little
     with time.

     Table 7.2 shows the results of water quality analysis  on May 21 and 22. From
table 7.2, the followings are found.
1)  The NH3 -N removal was nearly 100%. Considering the fact that the residual
     chlorine concentration was low, the state was close to the breakpoint.
                                   -  285  -

-------
2)   The formations of NO3-N were 0.56 mg/1 and 1.62 mg/1,  which were little
     higher than in the laboratory tests.
3)   The removal of CODMn was about 12.5%.
4)   Chloride concentration in the effluent was increased by about 100 mg/1.

7-3-3  TROUBLES OVER THE OPERATION  AND PERFORMANCE
     The following problems have been brought to the fore since the start-up of the
     pilot plant.
1)   When  the  ambient  temperature  rises,  sodium  hypochlorite decomposes,
     reducing available chlorine.  The decomposition becomes significant when the
     temperature exceeds 25°C.  It was necessary, therefore,  to install a dial on the
     controller to correct the change in NaOCl concentration. The concentration is
     checked periodically and the dial is adjusted manually.
2)   NH3-N concentration detected  by  the colorimetric type automatic ammonia
     analyzer is a little lower than by the manual Nessler's method.  This problem is
     being examined.
3)   It has been  found that ammonia  electrode has a short life.  The necessary
     frequency of  calibration is under study.

7-4.  FUTURE RESEARCH
     As far as  the removal  of  ammonia nitrogen  is  converned,  the breakpoint
     chlorination is very effective. However, addition of chlorine into liquids like
     sewage which  contains a large  amount of organic matter may cause serions
     problems. The following are left for the future study.
1)   Material balance in the reaction between chlorine and ammonia.
2)   Removal of chloramines and  chlorinated  organic compounds by activated
     carbon adsorption through laboratory and pilot scale studies.
                                     286  -

-------
                                                   Table 7.1  Results of operators performed 5/16/75 - 5/22/75
                                                                                                                        Influent of Carbon Contactor
tsj
CO

5/16
5/17
5/18
5/19
5/20
5/21
5/22
16 : 00
">0 : 00
23 : 00
4 : 00
8 : 00
11 : 00
16 : 00
20 : 00
24 : 00
3 : 00
8 : 00
12 : 00
16 : 00
20 : 00
24 : 00
4 : 00
8 : 00
16 : 00
20 : 00
24 : 00
4 : 00
8 : 00
12 : 00
16 : 00
20 : 00
24 : 00
4 : 00
7 : 00
11 : 00
16 : 00
20 : 00
Flow
rate
m3/day
260
251




255
251
248
CI/N
Wt.
ratio
10
10




10
10
10
NaOCl
Concen-
tration
W/V
Of
14.08
14.08




13.86
13.86
13.86
Injection Pump
Stroke
(%)
-
measure
65
-



59
-
VS
Motor
(rpm)
-
nent 8 : 30
350





370
~
Dose
Rate
Calc.
(ml/min)
-
104





96
-
Dose
Rate
Obs.
(ml/min)
-
100





90
-
Obs./Calc.
-
0.96





0.94
-
Colorimelric
Analyzer
Influent
NH3-N
(mg/1)
9.70
10.10
9.75
8.45
8.05
8.50
9.60
8.60
7.25
6.70
6.10
6.15
7.90
10.20
10.90
10.25
9.05
6.20
7.00
7.15
7.10
7.00
7.35
8.40
9.25
9.30
9.00
8.60
8.35
9.10
9.95
Effluent
NH3-N
(mg/1)
0
0
0
0
0
0
1.35
LOO
0.70
0.80
1.60
2.35
1.20
6.55
4.00
0
3.10
0
0
0
0
2.00
0
0.55
0
0
0
0
0
6.20
2.85
Note
Calibration 24 : 00







-------
                                                                          Table 7.2  Results of Tests
                                                                                                                  Influent of Carbon Contactor
CO
co

5/21 9 : 00
C1/N = 10
NaOCl Cone.
13.86%(W/V)
5/22 9 : 30
Cl/N = 10
NaOCl Cone.
13.86%(W/V)
Influent
Effluent
Removal
Influent
Effluent
Removal
PH
6.94
7.24
-
7.01
6.91
-
CODMn
(mg/1)
11.5
10.1
12.1
12.6
11.0
12.7
K-N
(mg/1)
7.46
0.43
94.2
10.57
1.01
90.4
NH3-N (mg/1)
Auto-
matic
7.10
0
100
8.40
0
100
Manual
6.15
0.03
99.5
7.25
0.01
99.9
NO3-N
(mg/1)
8.00
8.56
-
8.03
9.65
-
cr
(mg/l)
56.20
166.67
-
58.14
156.98
-
Cl
Residual
(mg/1)
-
1.60
-
-
2.14
-

-------
                            Cl Residual
                                  (mg/8)
                            (N02+N03)-
                            N    (mg/2)
                                              3
                                              yo
                                              VI
                                              OJ
                                   10
Fig. 7.1  Effect of pH on Chlorination


Cl/N = 8 (wt. ratio), Total alkalinity = 31.5 mg/2
              289

-------
O
                                     X	pH after chlo-
                                         rination   X
                                                 10
               Fig. 7.2  Chloramine Formation
                          290

-------
                               Total Alkalinity = 86.7 mg/6
    10-
                    -50
ex

Z
Q
Z
     6-1
     4-
Z   2-
                                                                  3
                                                                 •O
                          oi

                          o
                               Total Alkalinity = 45.0 mg/fi
    10-
     6-
     4-
         Total Alkalinity = 1  me/C
    10 -
O  3

-f
 ra
O  ,,
Z  6
 ^  4 -
	O	NHj-Nfma/a)

	C — Cl Residual.,
             (ms/C)
— • — (N02+NO%)-N
             (ma/C)
   X-pH
-50



-40



-30



•20



•10



 0





-50



•40



-30



-20



-10



 0
                      6780


                         C1/NH3-N (wt. ratio)
           Fig. 7.3  Breakpoint Chlorination and pH
                            - 291  -

-------
    20_
is


o
 (N
u
X


G

u
15-
    10-
     5-

pH=4.5
PH=7.5
NH2C1-C1
-0-
-o-
NHC12-C1
-0-
-o-
         056      78     9


                   Cl/NH3-N(wt. ratio)





           Fig. 7.4   Chloramine Formation
                     292  -

-------
   10-
"5.
O  6-
i   4
     0 "—
                                  NH3-N
                                  Cl Residual (mg/£)
                                  (N02+N03)-N(mg/e)
                                  pH
                      6789
                       C1/NH3-N (wt. ratio)
                                                     11
- 50

-40
                                                          \- 20
                                                          h 10
           Fig. 7.5  Breakpoint Chlorination and pH
                 Total Alkalinity - 5.5 mg/£
                           -  293  -

-------
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°§Ja

-------
CHAPTER 8.   PHOSPHATE REMOVAL  IN AN ACTIVATED SLUDGE
              FACILITY BY ALUM ADDITION
8.1   Outline of Nishiyama Sewage Treatment Plant	296
8.2   Installed Equipment and Devices	297
8.3   Chemical Addition Control	297
8.4   Outline of Methodology	298
8.5   Results and Discussion	298
8.6   Summary	302
8.7   Future Research Project	303
                                  295 -

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8.    PHOSPHATE  REMOVAL IN  AIM ACTIVATED  SLUDGE  FACILITY  BY
     ALUM ADDITION

     Putting newly planned sewage treatment plants aside, the existing sewage treat-
ment plants are said to permit  of almost no expansion for functional improvement
including phosphorus removal because of difficulties involved in the acquisition of
rights-of-way. To ward off this problem a method of dosing coagulants like metal
salts, into existing  facilities such as  aeration tank has been brought into limelight.
This is because the  expansion work can be limited to a minor extent - to the installa-
tion of chemical storage tank, dosing pump and additional sludge treatment facility
to overcome  excess waste sludge to be developed as a result of chemical  dosage.
     This method has been evaluated in various ways by E.P.A. of U.S.A. and some
countries in Europe, and has been put to practice. In Japan, the raw sewage is usu-
ally weak in strength, and the data concerning the treatment of this kind of sewage
in this method have been called for.
     For example,  the domestic sewage in Japan is characterized by BOD of 100 to
180 mg/1. and T-P of 4 to 6 mg/1.
     The Public Works Research Institute of the  Ministry  of Construction  and
Nagoya Municipal Government formed a joint project for a demonstration survey at
Nishiyama Sewage  Treatment Plant, which is taking in domestic sewage typical of
Japan,  of the  effects of coagulant on upgrading of the existing plants.
     The results of survey will  be used not only  for Nagoya Municipal Government
but also for those cities that are suffering from similar problems in the upgrading of
existing sewage  treatment facilities. The purposes and objective  of the survey to be
undertaken by this  project are summarized below.
i)    Study for a method of reducting the residual phosphorus concentration in ef-
     fluent below 0.5 mg T-P/lit.
ii)   Study on the  impact on the entire functions of plant including increased sludge
     production.
iii)   Study on the effects of metal salts on biological treatment.
iv)   Study for  a  method of promoting removal of phosphorus and nitrification
     simultaneously.
v)   Study for  a method of removing suspended solids  in effluent by rapid sand
     filtration, polymer addition, etc.
vi)   Study for a recovery method of dosed metal salts.
vii)  Development of instrumentation and automatic control techniques
viii)  Economic assessment

     The demonstration project was started  in  1974. Now, alum addition  into an
aeration tank is in  the progress. The  following is an  interim report of the survey for
the period from 1974 to July 1975.

8.1  OUTLINE OF NISHIYAMA SEWAGE TREATMENT  PLANT
                                     296

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     Nishiyama Sewage Treatment Plant is a comparatively small sewage treatment
plant for domestic sewage only. The sewage collection is of the separate sewer type,
and  the conventional plug flow activated  sludge system is adopted  for biological
treatment.
     Table 8.1 shows an outline of the design and Table 8.2 an outline of the facili-
ties.
     This small-scale domestic sewage treatment plant is always facing vilolent fluc-
tuation in both quality and quantity of influent, and thus has been greatly in need
of chemical dose control.
     Fig. 8.1 shows diagonal variation of T-P and Sol T-P in the influent.
     As shown in Table 8.2, this plant is separated into two bays, and a modification
was made to use one bay as a control and the other as a chemical addition train for
the purpose of comparing them while running under the same operating conditions.
     The modification includes separation of  return sludge  influent channel and
separation of channel leading from the aeration tank to final sedimentation  basin.
The  sludge had been  returned from a hopper of the final sedimentation basin via a
pump well, and a submerged pump was installed at  one bay to permit direct sludge
return and withdrawal of excess waste sludge. In this way, the basins were complete-
ly separated from each other. But later, seepage, though little, was found between
the two.
     The flow diagram of the facilities is shown in Fig. 8.2.

8.2  INSTALLED EQUIPMENT AND  DEVICES
     Installed for the purpose of  chemical addition were chemical storage tank
(15 m3), chemical pump, and chemical control equipment.
     The pump used was a plunger type  one capable of changing both speed and
stroke.
     Its injection control range was 1 : 30 or 5 to 135 lit./min.

8.3  CHEMICAL ADDITION CONTROL
     The chemicals were planned to be dosed  to be proportional to phosphorus
loadings., measuring phosphrus, by automatic colorimetric analyzer.
     At present, however, we  are in the process of developing an equipment for
automatically measuring the phosphorus concentration in the  supernatant of mixed
liquor and proportional dosing has not yet been achieved.
     For this reason,  the  delivery rate of the dosing pump was controlled to follow
the signal representing the change in influent flow.
     The dosing rate  was predetermined. Namely, the alum has been dosed to make
a constant mole ratio of A/P with respect to daily average phosphorus  concentration
of the influent.
     In this system, if the change in the influent flow takes place in the same way as
the change in  quality, proportional  control of chemical  dose can be achieved. As
illustrated in Fig. 8.2, the qualitative and quantitative changes do not always take
place in  the same way. At present, the dosing rate is determined with the daily
average phosphorus concentration taken as 4 mg T-P/lit.
                                     297

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     The dosing pump motor frequently failed for some time after start-up of the
project.
     It was then found  that a sharp decline in the influent flow into the aeration
tank due to withdrawal of sludge from the primary sedimentation basin outpaced
the dosing pump. To overcome this problem, the motor speed was reduced when the
influent flow decreased sharply. Now the dosing pump is well in service.

8.4  OUTLINE OF METHODOLOGY
Coagulant and its addition
     The coagulant used was liquid  aluminum sulfate (alum). Its chemical formula
is Ah (SO4 )3 • 18H2 O, and Ah O3  accounts for some 8%.
     Dosing rate was set at  2 in terms of mole ratio of Al/P to T-P in influent or
8 mg/lit. in Al. The dosing position of alum was at the end of the aeration tank.
     Later  it  was found that around  this position T-P in  the supernatant of mixed
liquor is in many cases about 60% of that in the influent, and the dosing rate now is
reduced half,
Sampling procedure
     Samples were taken by an automatic sampler at an interval of 2 hrs to make up
a 24-hr composite sample. The analysis was made 3 to 4 days a week.
Measuremet of sludge
     For both bays, the waste sludge was measured with an electromagnetic flow-
meter and an ultrasonic solid meter automatically.

8.5  RESULTS AND DISCUSSION
     Addition of alum into the end of the aeration tank started in  early February,
1975. The dosing rate remained the same until July, but the period was divided into
two: Phase I from the start to March 30 when water temperature was low and Phase
II from mid-April to the end of July when water temperature rose above  11°C.
     Table 8.3 shows the characteristics of the qualities of influent and effluent.
     Table 8.4 shows the summary of operating conditions.
     In Phase II, the influent flow was a little larger than in Phase I; so was MLSS.
Phosphorus removal
     Removal of phosphorus was drastically improved by the addition of alum.  As
seen in the table, both Phase I and Phase II  saw a reduction of residual phosphorus
concentration in effluent to 0.4 mgP/lit. in T-P and 0.3 mgP/lit. in Orth-P.
     In both  phases,  the phosphorus concentration in the influent  was around 3.5
mg/lit., and the removal efficiency was kept of about 90%.
     Up until  now, the operation  has been continued for about  six  consecutive
months with a Al/P mole ratio set at 2. During this entire period, T-P in the effluent
has always been kept below 0.5 mg/lit., proving that so far as this dosing rate is used,
the target residual phosphorus concentration of less than 0.5 mgP/lit. can be  at-
tained.
     In the demonstration  paint,  the  control bay also showed a comparatively high
phosphorus removal of 45  to 55% or less than 2 mgP/lit. in terms of residual phos-
                                     298

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phorus concentration.
     Now investigations are under way as to whether this is due to biological uptake
or coagulation by cations like Ca++ entrained with influent.
     In Phase I, the phosphorus  content in the activated sludge  in the control bay
was  1.7 to 1.9%.
Nitrogen removal and  nitrofication
     In Phase I when water temperature was low, neither dosed bay nor control bay
had  nitrification. But in Phase II,  the control bay alone experienced substantial nitri-
fication as water temperature rose up. In  early  July, the nitrification percentage
based on TKN reduction reached no less than about 60%. The transition is shown in
Fig.  8.3. Alum addition bay did not have nitrified effluent at all for all that it was
operated under the same conditions except for dosing. This may be due to depletion
of alkalinity or interference by aluminum.
     In the dosed bay, washout of suspended solids took place extremely in Phase II,
and  SRT was as low as about 2 days. This may also be attributable to the prevention
of nitrification. As shown  in Table 8.3, the influent alkalinity (85 mg/lit.) was con-
sumed 45 mg/lit. as CaCOs in the dosed bay by  the addition of alum, manifesting
the depletion of alkalinity necessary for nitrification.
     In the chemical bay, aluminum of some 8 mg/lit. was dosed. The accumulation
in the sludge reached about 12% in Phase II. Now laboratory test is under way as to
how this concentration of aluminum can interfere with the nitrification.
     As shown in Table 8.4, the settler has a large overlfow rate, and solids are liable
to be washed out. Accordingly,  MLSS in  tank cannot  be maintained high enough
whereby SRT cannot be maintained. To cope with this problem, a method of reduc-
ing the overflow rate is now under way.
     In winter this year, experiments will be made with consideration given to the
addition of alkalinity, intereference of Ar + + , and increase of SRT in hopes of pro-
viding something of a basis for the promotion of nitrification in the process.
Removal of organic matter
     Removal of both BODs and TOC was increased by the addition of alum. Com-
pared with the control bay, the dosed bay showed an increase of some 5% in removal
of BOD and some 10% in removal of TOC.
     In Phase II, the removal  slightly went down in the dosed bay, which might be
attributable to washout of solids.
     Soluble  BOD  in the effluent was  3.6  mg/lit. and  soluble TOC 17 mg/lit., or
55% and 82% to total, respectively.
Solid removal
     Phase I and Phase II showed a sharp contrast in the removal of suspended solids.
     In Phase I, the residual solids in the effluent was smaller in the dosed bay than
the control bay, whereas in Phase II, the control bay showed a  smaller value than
the dosed bay.
     This might have been due to  the following causes.
1)   Washout of floe produced  by aluminum dose after being transformed into
                                    299

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    particulates.
    In Phase 1, data covered comparatively earlier stage of dose though taken after
    a cell residence time, and washout of fine floe was not noticed.
    Aluminum content in the solids in the dosed bay was 7% in Phase I and more
    than 10% in Phase II.
2)  In Phase II, the overflow rate in the control bay was half as much as that in the
    dosed bay.
    Washout was observed in the morning when influent flow was large.

    As shown in Table 8.3, the turbidity also showed the same tendency as SS.
    From Oct. this year, a rapid sand filter plant will start operation  in order to
launch into a project for solid removal from the  effluent.
pH  reduction and alkalinity consumption
    pH reduction was not so serious as expected. pH reduction due to addition of
alum is about  1 unit, and pH at the end of aeration tank immediately after dose was
about 6.1.
    Alkalinity is consumed by chemical dose. Addition of 1 mg/lit. of Af++ resulted
in consumption of alkalinity by  5.5 mg/lit. max. as CaCOs.  In the dosed bay, the
consumption was 40 to 45 mg/lit. which corresponded  to 8 mg/lit. of added Al+++
considering the portion used for  coagulation of phosphorus. In Phase II, dosed bay
saw an alkalinity consumption of some 30 mg/lit. which may have been due to nitri-
fication.
    Alkalinity of influent running into Nishiyama Sewage Treatment Plant is 80 to
120 mg/lit.  For perfect nitrification or in the vent of dosing when the phosphorus
concentration is high, addition of alkalinity will  be almost indispensible.
    This may be a matter common to all the sewage treatment plant in Japan which
are processing domestic sewage.
Effects on biological activity and microfauna
    The survey of the effects of high-concentration aluminum dose to aeration tank
on microfauna in the activated sludge was one  of the greatest interests attached to
the project.  Some reports of similar surveys claim that such dose have little  effect on
the microfauna. In the project, no particular effects were found so long as  the efflu-
ent quality was concerned, though VSS decreased from 70% to 60%.
    Table  8.5 shows the results  of microscopic observation of population number
of microfauna in the activated sludge in  both bays in Phase II.
    The differences between the two bays were as follows.
1)  Alum  dose  decreases the  number of organisms in  the activated  sludge  on the
    whole.
2)  Number of species of microfauna in the activated sludge is decreased. Fig. 8.4
    shows time-dependent change of the number of individuals  of ciliata per unit
    MLVSS.

    In Phase II, the effluent of dosed bay became milk, white sometimes after rain-
fall. At first, it was considered attributable to the promotion of washout of fine floe
                                     300

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of aluminum hydroxide.  Later, it was found by a microscopic observation to be
swarms of bacteria analogous to spirochaeta plicatilis.
     The bacteria oftentimes were found even in fine weather, though they were
little in number.
     The reason why they grow so far as to turn the effluent milk white is still un-
known. Whether the bacteria is spirochaeta plicatilis or not is under study.
Sludge production
     The sludge production rate is compared in Table 8.6 between the two bays over
the 11-day period during which aluminum  concentration in the mixed liquor was
considered stable.
     As touched upon  in the foregoing, a little seepage was noticed between the
mixed liquors of both bays.
     In Table  8.6,  the  seepage is  compensated for with aluminum addition in the
control bay  as a basis. As shown  in Table 8.6, the sludge production in the alum-
dosed bay increased as compared with the control bay. The daily average sludge pro-
duction rate over the 11 day period was 613 kg/d. (45.4 mg/lit.) in the control bay
as against 856 kg/d. (72.5 mg/lit.) in the alum dosed bay. Namely, alum dose created
an increase  of some 30%. During this period, BODs  removal  was 590 kg/d.  (56
mg/lit.) in the control bay as against 640 kg/d. (61 mg/lit.) in the alum dosed bay,
with a difference of 50 kg/d. (5 mg/lit.) between the two. It is evident that produc-
tion  of aluminum phosphate and  aluminum hydroxide due to alum addition has a
direct influence over the increase of sludge production.
     Assuming that  precipitation reaction of alum follows the following  formula,
and that  3 mg/lit. of phosphorus in the influent is precipitated with Ar++, the pro-
duction of sludge due to alum addition will be 184 kg/d. (15.6 mg/lit.) in the form
of aluminum hydroxide and  139 kg/d. (11.8 mg/lit.) in the form of aluminum phos-
phate.
     A12(SO4)3 +6HCO3 ^2A1(OH)3  +3SO4-2 + 6CCh
     A12(SO4)3 + 2PO4-3 -» 2A1PO4 + 3SO4-2
     Namely, Aluminum in the sludge in this case will amount to about 110 kg/d or
some 12% of the total sludge volume of 856 kg/d. This estimate showed relatively
high  agreement with the observed value.
     It was  very interesting  to notice during the  period that the increment in the
alum dosed system washed out along with the effluent.
     As regards the sludge production, data collection will be made from a long-term
standpoint.
Dewaterability of the chemical sludge
     Dewaterability  of alum-treated sludge was  examined. For the time  being, a
filter leaf test modeling after vacuum filtration is under way.
     Interim results may be summarized as follows.
1)   For the dewatering of  waste sludge developed by alum addition, dose  of cal-
     cium hydroxide and ferric chloride in combination as conditioner is effective.
2)   For sludge with solid content of 2.5% and aluminum content of 10%, filtration
                                    301

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    velocity can be 10 kg/nr /hr when calcium hydroxide is dosed 50% and FeCb
    5%. The moisture content of cake in this case is about 85%.
3)  There is little difference in dewaterability of waste activated sludge between
    control bay and dosed bay.
4)  Dewaterability  can be improved sharply  by adjusting  the ratio of chemical
    sludge to primary sludge.

    The above refers to the dewatering of raw sludge. In Japan, the dewatering is
practised mostly after anaerobic digestion,  and  study will be  made on the dewater-
ability of sludge containing metal salts after anaerobic digestion.
Cost of chemicals
    If the sewage is to be treated with Al/P mole ratio of 2, its treatment cost is
estimated  at ¥1.78/m3 (2.32 ^/1,000 gal.)  based on the cost of liquid alum  pur-
chased by  the Nagoya City.
    The sewage considered here contains  an average phosphorus concentration of
3.5 mg/lit., and the residual phosphorus concentration in the effluent is less  than
0.4 mg/lit. If the phosphorus concentration removed is 3 mg/lit., the chemical cost
per removal concentration is estimated to be ¥0.59/m3/mgP/lit. removed  (0.774  
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     the addition of alkalinity and effect of aluminum;
4)   the microfauna in the dosed bay became different from that in the control bay,
     showing extermination or decrease of population and species;
5)   the sludge production increased some 30% to 40% from that in the control bay,
     increment being attributable to the addition of aluminum;
6)   organic matter in MLSS was reduced in alum dosed system to 60% as against
     70% of the control system.
7)   keeping MLSS at a high level was difficult,  mainly because of high overflow rate
     observed  in the  final sedimentation tank, and as a result, SS in the effluent was
     increased compared with the control;
8)   no trouble  was  developed in the treatment by the low MLSS, suggesting that
     running at a low MLSS may  be practicable where  the influent is weak as with
     the sewage in Japan;
9)   the alum dosing  cost was ¥l.78/m3 (2.32 c/1,000 gal.). An experiment with a
     decreased dosing rate is under way, and precise cost analysis will be made  soon.

8.7  FUTURE RESEARCH PROJECT
1)   Determination of minimum  alum dosing  rate necessary  to keep the residual
     phosphorus concentration in the effluent below 0.5 mgP/lit.
2)   Study on the promotion of nitrification when alum dosing is practised.
3)   Clarification of sludge production balance.
4)   Establishment of proportional chemical dosing control system.
5)   Feasibility study on the recovery of slum.
6)   Study for a method of removing solids in the effluent

     At present, a rapid  sand  filter pilot plant having an effective surface area of
1 m2 is under construction at Nishiyama Sewage Treatment Plant. Its operation is
scheduled for early Oct. this year.
     This filter is  divided into 8  basins, and when on basin is being subjected to
backwashing, the effluent of the other basins is used as backwash water.
     This is accomplished automatically according to the total head loss increased.
The  transfer of backwash  water  is undertaken by siphon effect,  dispensing with
valves otherwise required.
     This automatic backwashing, valveless rapid sand filter will be used at once for
the testing  of solid removal from the secondary effluent and for  the collection of
basic design data necessary for engineering the application of this kind of filter to
the solid removal from the secondary effluent.

7)   Examination  of merits and demerits of dosing  coagulants into primary sedi-
     mentation basin.
8)   Dosing of iron salts and the like other than alum.
9)   Economic appraisal
                                  -  303  -

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Table 8-1  Outline of Nishiyama STP
Area served
748 (ha)
1,850 (acre)
Population
served
46,000
Volume of sewage flow
Daily average
20,000 (m3/d)
5.7 (mgd)
Daily maximum
30,000 (m3/d)
7.9 (mgd)
Collection
System
Separate
Sewer
               304

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                          Table 8-2   Outline of Nishiyama Facilities
^•v. Item
Facility ^\
Grit
chamber
Preparation
tank
Primary
settler
Aerator
Final settler
Type
Rectangular
Diffused
aeration
Rectangular
Diffused
aeration
2 storied
rectangular
Dimension (m)
W L H
2.5 x 10 x 1.85
4.0 x 20 x 3.5
5.0 x 28 x 30
5.0 x 40x50x2 bay
, n 1st 22.5 0 n
5'0x 2nd 27.5 X3'°
Number
2
1
4
2
3
Total
volume
(m3)
-
245
1,680
4,000
2,250
Design
detention
time
1.2min.
1.3 min.
1.3hr.
3.2 hr.
l.Shr.
Notes: 1.  Influent coming in by gravity.
       2.  Sludge is being treated at the adjacent plant.
                                          -  305  -

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Table 8-3  Summary of Influent and  Effluent Quality (Phase I)
                                                                                   Feb. 25 ~Mar. 26, 1975
^^\^^ Item
Category ^^^^
Temp (°C)
pH
Transparancy
Turbidity
SS (mg/C)
Total Alkanility
BOD5 (mg/C)
COD (mg/C)
TOC (mg/C)
T-P (mg/C)
Orth-P (mg/C)
TKN (mg/C)
NH3-N (mg/C)
NO2+NO3-N(mg/C)
Raw sewage
Average
-
-
-
130
135
94
100
69
78
3.44
2.95
22.8
12.2
0.4
Range
11.6~13.6
6.95-7.50
2.0-4.5
67—223
60~232
79~118
96 — 104
54 — 110
77—80
2.80 — 4.40
1.5-6.56
22.5 —23.0
11.3 -13.1
0.1—0.3
Primary effluent
Average
-
-
-
83
52
92
67
48
69
3.44
2.25
23.7
13.9
0.2
Range
11.8—13.6
6.76—7.60
3.0-8.0
51 —111
34—77
69-112
51 —83
42—61
67-72
29.3-4.0
1.71-3.33
22.4 — 25.0
13.2-14.6
0.1 —0.3
Secondary effluent
(Control)
Average
-
-
-
14
12
87
8
14
40
1.95
1.42
18.8
14.1
0.3
Range
11.7—13.6
6.94 — 7.70
15.2~30<
26—65
2-36
70-103
9-16
12 — 17
38-42
1.3-2.7
0.91-1.67
18.6-19.0
14.0 — 14.2
0.28—0.32
Secondary effluent
(Alum, addition)
Average
-
-
-
7
6
52
5.3
10
17
0.27
0.13
17.4
14.4
0.3
Range
11.7 —13.6
6.35-7.30
2.4- 3.0 <
1 -25
2-H
43-65
5.0-5.5
9 — 11
11 —24
0.2-0.4
0.08—0.28
16.9 —17.8
14.0 — 14.7
0.15 —0.34
Removal efficiency
over secondary
Control
-
-
-
83.1
76.9
21.7
88.0
70.8
42.0
43.3
36.7
20.7
-
-
Alum. add.
-
-
-
91.6
88.5
43.6
92.1
79.1
75.3
92.2
94.2
26.5
-
-

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Table 8-3 Summary of Influent and Effluent Quality (Phase II)
                                                                                 April 12—June 30, 1975
^^^^ Item
Category ^^^^
Temp (°C)
pH
Transparency (cm)
Turbidity (mg/2)
SS (mg/2)
Total Alkalinity
(mg/fi, CaC03)
BODS (mg/2)
COD (mg/£)
TOC (mg/£)
T-P (mg/£)
Orth-P (mg/S)
TKN (mg/C)
NH3-N (mg/S.)
NO2+NO3-N(mg/£)
Raw Sewage
Average
-
-
-
80.3
118
80.5
98.7
56.1
80.1
3.54
2.16
25.2
14.3
0.11
Range
16.0—21.8
6.8—7.2
2.5-5.5
56.5-132
81-162
59 — 126
68.8 — 124
36.4—76.4
51.8-122
2.59—4.92
0.81 -3.20
21.8-29.1
12.1 — 16.8
0.0 — 0.28
Primary effluent
Average
-
-
-
52.02
41
85.3
64
41.4
58.8
3.45
2.24
25.8
15.7
0.04
Range
16.0 — 21.8
6.8-7.2
3.0-7.0
32.5-92
31-78
62-135
47—95
32.3-55.7
38.4—87.0
2.01-7.90
0.79—4.40
20.6 — 39.1
12.2—25.5
0-0.10
Secondary effluent
(Control)
Average
-
-
-
6.7
6
55
9.5
11.3
19.3
1.49
1.25
13.2
9.7
3.17
Range
16.4 — 21.8
6.6-7.2
1.7—30
4.1 — 11.3
2 — 11
30-95
6.5 —16.5
8.3-14.5
8.1 -36.0
0.67—3.21
0.59-1.97
9.9-21.0
6.6 — 17.4
0.20-6.7
Secondary effluent
(Alum, addition)
Average
-
-
-
15.7
21
39
6.4
12.5
14.9
0.39
0.31
17.8
14.1
0.35
Range
16.4-21.8
6.4-7.3
6.5—30
3.5-62
2.0 — 66
13.5—53.5
4.7—8.3
7.0-37.5
7.1-22.3
0.14 — 0.69
0.06—0.75
16.0-21.6
12.3-16.4
-0.07 -0.83
Removal efficiency
over secondary
Control
-
-
-
87.1
84.5
-
_ 85.1
72.7
67.1
56.8
44.2
49.1
38.3
-
Alum. add.
-
-
-
69.9
49.7
-
90.0
69.8
74.6
88.7
86.2
31.3
10.3
-

-------
                                                             Table 8-4  Summary of Plant Operation
^^ Item
Category \^
o
C^)
C3
0^
o>
CO
n3
OH
Control
Alum, addition
Control
Alum, addition
Average
daily flow
(m3/d)
10,650
10,650
11,800
11,800
Aerator
Aeration
time
(h)
4.5
4.5
4.1
4.1
Return
sludge rate
(%)
30
30
30
30
Air flow
rate
(times)
4
4
4
4
MLSS
(mg/£)
640
950
1,030
930
MLVSS
(mg/2)
460
645
717
560
SVI
117
115
105
111
Organic
load
(kg BOD/kg SS)
0.55
0.37
0.36
0.40
Final settler
Detention
time
(hr)
1.7
1.7
3.1
1.5
Overflow
rate
(m3/d/m3)
42.6
42.6
24
47.2
OJ
o
CO

-------
                                                    Table 8-5   Microfauna in Activated Sludge (Alum. Addition)
                                                                                                                                              (N/ml)
s^k^^e^a
Euglena
Unknown
flagellata
Tetrahymena
Litonotus
Unknown ciliata
Aspidisca
Vorticella
Opercularia
Carchesium
Zoothamnium
Epistylis
Rhabdostyla
Tokophrya
Rotaria
Nematoda
May 20
-
60
40
-
-
-
60
-
-
-
80

20
-
-
May 22
-
180
20
-
-
20
20
-
40
-
80

40
-
20
May 23
200
40
20
-
-
80
100
-
-
-
120

140
20
20
May 28
-
-
-
-
-
-
100
-
-
-
140

-
-
20
June 2
-
-
-
-
-
20
240
-
80
-
40

-
-
40
June 4
-
-
20
-
-
20
720
-
80
-
160
100
60
-
20
June 5
-
-
-
-
-
40
200
-
-
-
20

-
40
-
June 9
-
-
-
-
-
-
40
-
-
-
-

80
20
-
June 12
-
-
-
-
-
-
200
-
-
-
140

140
40
-
July 2
-
-
-
-
-
40
120
-
-
-
200

220
-
20
o
(£3

-------
Table 8-5   Microfauna in Activated Sludge (Control)
                                                                                         (N/ml)

Euglena
Unknown
Flagellata
Tetrahymena
Litonotus
Unknown ciliata
Aspidisca
Votticella
Opercularia
Carchesium
Zoothamium
Epistylis
Rhabdostyla
Tohophrya
Rotaria
Nematoda
May 20
40
-
260
60

620
-
-
-
-
640

-
20
-
May 22
-
80
320
-

340
80
-
-
220
80

100
20
20
May 23
420
730
2,000
380

780
160
-
-
-
160

240
-
-
May 28
-
+++
260
720

300
720
-
-
-
1,080

180
-
-
June 2
-
+++
580
-
160
760
500
-
100
-
2,160

120
60
-
June 4
-
+++
120
—

160
2,040
-
200
-
3,260

300
20
-
June 5
-
+++
-
-

-
260
-
-
-
4,050

60
20
-
June 9
-
+++
86
-

500
2,080
-
220
80
1,080

160
200
20
June 12
-
100
-
-

500
980
-
360
-
40

100
120
40
July 2
-
+++
2,340
-

640
820
20
-
40
200

20
320
40

-------
                Table 8-6  Comparison of Sludge Production
           Sludges
Control
Alum, addition
     Waste activated suldge
                  kg/d.
                  (mg/B)
     Solid in effluent
                  kg/d.
                  (mg/2)**
     Total
                  kg/d.
                  (mg/C)**
     Addition as A^OH^
                  kg/d.
                  (mg/2)**
     Addition as A1P04*)
                  kg/d.
                  (mg/£)**
  536
 (45.4)
   77
  (6.5)

  613
 (45.4)
     545
    (46.1)

     310
    (26.2)

     856
    (72.5)

     184
    (15.6)

     139
    (11.8)
*) Calculated value.   **) Based on inflow.
                                 - 311  -

-------
    7 _,
    6  -i
o
2   5
3.   4  -
s
_o
u_   3
    1  -
               —I	
                 15
                8/29
20
               1           5
                   8/30
     10

Time and Date
15
              20
—i—
 10
                                8/31
                            Fig. 8.1   Fluctuation of  Flow Rate and Phosphorus Concentration in Primary Effluent

-------
Raw Sewage
Preaeration

  Tank
Primary

  Settler
                                                   I	
                                                              Return Sludge
                                                                 Aerator
                                                                                                    - -f P )	•+*   Waste Activated Sludge
                              Alum Addition Bay
                                                                                       Final Settler
                                                                                                            Chemical Storage Tank
                                                                           Chemical Feed Pump
 cu
J_
                                                  Fig. 8.2   Flow Diagram of Nishiyama STP

-------
    30
J_
Z
O
                                                     Legend
                                            Control
                                   TKN	O	
                                   NH3-N	•	


                                   N03-N	A,	
                                                                                         Alum Addition
    20
Z
Z
    10 H
         -^     V'
               *\       \
                                                                                  /
                                                                                                    \
                                                                                                      XI
                 3/5
3/12        4/2
4/23        5/27
                                                                      6/3
                                                     6/10
                                                                                           6/19
                                                                                                      6/24
                                                                                                              1975
                                                                 Date
                                  Fig. 8.3  Weekly Change of Nitrogen in Final Effluent

-------
10"
103
102
                                           Total Ciliata (Control)
                                     	Activated Sludge Ciliata (Control)
                                           Total Ciliata (Alum Addition)
                                     	Activated Sludge Ciliata (Alum Addition)
10
       3/5    6     13    4/3    24   5/20   22    23    28    6/2    4
                                            Calendar date
5     9     12    7/2
                   Fig. 8.4   Changes  in  Microfauna in the Activated Sludge
                                              315

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CHAPTER 9.   PILOT  PLANT STUDIES OF PHOSPHORUS REMOVAL FROM
              SECONDARY EFFLUENT TO PROTECT LAKE BIWA
9.1   LakeBiwa	317
9.2   Present Situation of Water Quality at Lake Biwa	321
9.3   Eutrophication Control and Effluent Quality Standard  ....     .   .323
9.4   Removal of Phosphorus	327
  9.4.1   BackGround	327
  9.4.2   Pilot Plant for Phosphorus Removal  .       	         .327
  9.4.3   Phosphorus Removal	      ... .330
9.5   Sludge Handling  .      .            	       ...       .   .330
  9.5.1   Alum Sludge	               .                .  .  ..330
  9.5.2   Thickening.       	331
  9.5.3   Dewatering       	                 	331
9.6   Further Research Needs ...      	          	334
  9.6.1   Loading of Phosphorus and Nitrogen on Lake Biwa   	334
  9.6.2   Further Pilot Plant Study	       	335
                                  316

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9.1  LAKE  BIWA
     The Biwa is one of the largest lake in Japan; 680 km2 in area, and it occupies
one sixth portions of total Shiga Prefecture area.
     Almost all the area of Shiga Prefecture is the basin at Lake Biwa.
     Yodo-River rise from Lake Biwa is the main water resource for Kyoto, Osaka,
and Kobe. These cities are located in one of the two most densely populated and in-
dustrialized areas, Tokyo and Kansai metropolitan areas, in Japan.
               Table 9.1  Geographical and Other Statistics at Lake Biwa
     Location
     Normal water level

     Total Area
     Main basin
     Sub basin
     Total basin area
     Total coast line
     Maximum depth
     Average depth
     Volume of water
     Retention time
Shiga Prefecture
85.614 m above Osaka Bay datum, Osaka pile
low water level
680 km2
610km2  (Northern Part)
70 km2 (Southern Part)
3848 km2
240km
103.58m
41.20m
27.5 x  109 m3
5.2 year
                                  -  317 -

-------
     Lake Biwa is very important water resource for navigation, irrigation, domestic
water supply and  industrial purposes.
                  Fig. 9.1  Water Usage from Lake Biwa and Yodo-River

                         (based on water rights)      June 1972
M.W.
I.U.
A.U.
O.U.
7.85m3/sec.
0.18m3 /sec.
1.35 m3/sec.
0.49 m3/sec.
M.W.
I.U.
A.U.
41. 97m3 /sec.
15.20 m3/sec.
16. 80m3 /sec.
       Kobe city
                          Katsura-river
                                    Kyoto city
                                                                      ;iwa
                                                              Shiga prefecture


Ohtsu
city
f
\
M.W.
I.U.
A.U.
O.U.
3.41 m3/sec.
3.04 m3/sec.
30.00m3 /sec.
8. 70m3 /sec.
M.W.
I.U.
A.U.
0.82m3 /sec.
1.88 m3/sec.
3.25 m3/sec.
                             M.W.:  Municipal water supply
                             I.U. :  Industrial use
                             A.U.:  Agricultural use
                             O.U.:  Other use
                                        318

-------
 o.
 a
 WD

 C
D.


_O



O
      30
      20
      10
      10--
 6




 5-




 4




 3




 2 •









 0




15-
     10-
      5-
                                                        O  Hikone (Northern Part)



                                                        A  Yabase (Southern Part)



                                                        n  Seta River (Outflow of Lake Biwa)



                                                        X  A magase Dam (21 km downstream

                                                                        from Lake Biwa)
                          Fig. 9.2  Monthly Change in Water Quality-1
                                             319

-------
         4 --
o;
•a
o
o
(O
                 Environmental standard for Seta River
 (so
 Q
 O
 O
         2 -•
 OH
   0
0.15


0.10 --


0.05 --
      0.00
 £
 z
       1.0 --
      0.5 --
      0.0
            48
                                              Environmental standard for lake Biwa
                                                                            O Hikone
                                                                            A Yabase
                                                                            C1 Seta River
                                                                            X Amagase Dam
                              (NH,-N)+(N02-N)+(N03-N)
                                    6
                                    28
                                                                           49
                                            10
                                            4
10
26
                                                               28
—I—
 12      1
 20     23
 2
21
3
11
                        Fig. 9.2  Monthly Change in Water Quality - 2
                                                320  -

-------
9.2   PRESENT SITUATION OF WATER  QUALITY  AT  LAKE  BIWA
     Fig. 9-2 shows the results of a water quality survey at the Biwa and at its out-
flow, the Seta River. The  survey was conducted from 1973 to 1974.
     The water temperature is found to stand at as low as 5  to 6 degrees Centigrade
between January and March, then start rising gradually some time in May and reach
almost 30 degrees Centigrade in August. Then, it starts  down gradually. There ap-
pears no remarkable distinction in the temperature around the lake. pH value is at
approximately 7.0 to 7.5  at every point, but from summer to autumn it goes slightly
up  to 8 to  9. The rise of pH-value has  something  to do with the growth of algae.
     It seems probable that pH-value rose after CO2 underwater had  been reduced
due  to abundant growth  of algae. The transparency of Biwa Lake water is  low in its
southern part. It is approximately 2.0 meters or less all through the year. Although
it improves  a little from November to January,  the value does not exceed more than
2.5 to 3.0 meters.  Considering the fact that the transparency exceeds 40 meters at
Lake Mashu  in Hokkaido  Lake Baikal, in U.S.S.R, both of which are said to maintain
the highest  transparency  in the world, it can be concluded that the Biwa  has been
polluted to  a great extent. Even in the northern part where water is  said  to  be re-
latively  clean, the transparency at Lake Biwa stands at about 5 meters. This leads us
to consider  that northern Biwa is transforming from an oligotophic lake to a  meso-
trophic  lake. Chlorophyl  is a pigment which plays a main role in the photosynthetic
reaction of plants, and is classifiable into four kinds; namely, a, b, c and d. Among
these four, chlorophyl-a is contained in every kind  of algae and accordingly is used
to indicate the standing crop of algae  in a water basin.  The  content of chlorophyl—a at
Lake Biwa,  though slightly  variable according  to the data, was 1 to  3 micrograms
Og) per liter in the northern part and 5 to  13  micrograms per liter in the southern
part. The content of chlorophyl at lakes and marshes is reported by Ichimura and his
associates as follows:
                                         (concentration of Chlorophyl-a)

     oligotrophic lake               0.1   to    0.8   /zg/1
     mesotrophic lake                1   to     5   /zg/1
     eutrophic lake                10   to    60   jug/1

    Chlorophyle at Lake Suwa, the most eutrophic lake in  Japan, shows  30  to 60
micrograms  per liter between June  and September. With this in view, it  is judged
that the northern part of Lake Biwa has already turned into a mesotrophic lake and
the southern part  into a  eutrophic  lake respectively. There was a point where the
highest BOD (Biochemical Oxygen Demand) stood  at 3 milligrams per liter, but in
general each point showed such a relatively  low value as 1 to 2 milligrams per liter.
The  environmental water  quality standard for Lake  Biwa has been decided  to be less
than  1 milligrams  per liter in terms of COD (KMnO4-COD), but at any points the
COD value  in the  lake  water  exceeds  the  standard  and  especially  from August
through November it goes as high as 3 to 4  milligrams per liter. As compared  to the
result of a survey  in 1963 in  which the annual mean COD indicated 1.12 milligrams
per liter in the southern part of Lake Biwa, it is positively presumable that the pol-
                                      321

-------
                                                       Chlorella sp.
                                                                                      S. capricorrutum
A  Hikone
                   20
  2.8
  3.6
  5.9
 *6.28
  8.6
 10.4
 11.28
 12.10
  1.23
  3.22
                                     Chloiophyl-a
                            15
                                      10
                                                                              10
                                                                                        15
                                                                                                  20
                                                      &Z.
                                                    V///
tr. (CHI)
tr. (Sel)
B  Yabase
  2.8
  3.6
  5.9
  6.28
  8.6
 10.4
 10.26
 11.28
 12.20
  1.23
  2.22
                                                  IX/XXx
                                  V////////////////1
C  Seta River
  2.8
  3.6
  5.9
  6.28
  8.6
 10.4
 10.26
'11.28
 12.20
  1.23

D  Zezc
E  Amagase
      Dam
  5^
  6.28
 10.4
 10.26
 11.28
 12.20
  J.23
  2 22
                   Fig. 9.3  Comparison of The Existing Volume of Algae and AGP

                  A: Hikone    Northern Part
                  B: Yabase	 Southern Part
                  C: Seta Rivet... Outflow

                  D: Zeze	 Southern Part

                  E: Amagase Dam	 21 km downstream
                                                  322

-------
lution is in progress at Lake Biwa. The reason why COD stays low in winter and high
in summer and autumn seems to be because there appears an increase of COD owing
to the growth of algae. T-P is said to have interrelations, to a certain extent, with the
degree of eutrophication, since the valute of T-P includes phosphorus in the micro-
organism grown in the same water basin. And this is why T-P shows generally a high
value from summer through autumn when COD also stays high. In general, NH4-N is
the indication that the  water is polluted with aninal excreta or agricultural water.
However,  since NH4-N  is also oxidizable into NO2-N and NO3-N by the action of
bacteria, total inorganic nitrogen or T-N should be ingnored. Total inorgani nitrogen
stood at approximately 0.2 milligram per liter or less in the northern part of Lake
Biwa all year round, whereas in the southern part it showed as low as 0.1 milligram
per liter in autumn on the contrary to such a high value as 0.6 milligram per liter be
between February and June. This seems to have resulted from the reduction caused
by  the growth of algae, as total inorganic  nitrogen is normally consumed by algae.
While chlorophyl shows the existing volume of algae, i.e., the volume in existence of
algae appeared in the current lake water the AGP (Algal Growth Potential) indicates
a potential of the algal growth. The  sum of the two may  surely  correspond to the
"total force of eutrophication" Fig.  9.3  shows relations between the present algae
concentration and AGP. AGP at Hikone (in the northern part) during the wintertime
stands at almost 10 milligrams per liter or less. This means that for the prevention of
eutrophication, AGP should be kept at less  than 10 milligrams per liter during the
wintertime. To stop eutrophication in the southern part it seems necessary to keep
AGP down to 20 milligrams per liter or less. Further, at Lake Suwa which is said to
have been most eutrophicated in Japan, the water  quality in terms of COD is 5 to 8
milligrams per liter, 0.2 to 0.3 milligram per liter  in in T—P, about 0.20 milligram
per liter in PO4-P, 0.5 to 2.0 milligrams per liter in NH4-N and 11  to 38 milligrams
per liter in AGP (Chi.), respectively.  The southern part of Lake Biwa seems to have
already been polluted as badly as Lake Suwa.
    As  has been mentioned above, the pollution at Lake Biwa is severe. The urgent
countermeasures are in need now so  as to  prevent  the further pollution and eutro-
phication. Accordingly,  the Japan Sewage Works Agency, having  been entrusted by
the  Ministry of Construction and the Shiga Prefectural Government, started surveys
and research works to prevent the pollution  at Lake Biwa, especially its eutrophica-
tion.

9.3   EUTROPHICATION  CONTROL  AND EFFLUENT  QUALITY STANDARD
     Sewage Works Act  states that publicly  owned treatment work provide treat-
ment with effluent limitations. The effluent  standard for secondary treatments such
as activated sludge process is shown in Table  9.2
                                  -  323 -

-------
                      Fig. 9.4   Effects of Adding of Secondary  Effluent
                               (Activated Sludge) or Tertiary Effluent
                               (Alum Coagulation)
                                Algae Inoculated:  Chlorella SP.
                                Treatment Effluent Adding:  5 % (volumetric)
     80
     70
     60
     50
€   40
"So

OH
<   30
     20
     10
|    [  Control
V//\  Ferric chloride (50 mg/1)
*'/"  treatment water
§§g^  -ditto- (100 mg/1) - ditto-

•B|  Alum (50 mg/1) - ditto-

[•;.:'."•.'.•.[  -ditto- (100 mg/1) -ditto-

rillllllll  Effluent  of activated sludge
      process
        Hikone             Yabase- 1  Seta River

              Water sampled
               on 9 May, 1973
               Yabase—2

               Water collected
               on 29 No., 1973
Lct'tbank of
Seta River

   (Under the
   iron bridge
   of National
   Railuav)
Amagase Dam

   Water collected
  on 4 Oct., 1973
                                                   524

-------
           Table 9.2  Sewage Treatment Plant Effluent Quality Standard
Category
H
BODS
SS
counting
Coli group
Standard Value
5.8-8.6
less than 20 mg/1
less than 70 mg/1
less than 3,000 N/ml

BOD and SS can be removed efficiently in the activated sludge process. The process
can produce the effluent that fully satisfys the effluent quality standard established
by the Sewage Works Act if only due attention is paid to the operation and mainte-
nance. However, the effluent standard is now out of date. Recently the environ-
mental water quality standard is set up in the whole Biwa Lake.
     The actual allowable effluent quality is  a different story from the traditional
effluent  standard. The allowable effluent quality has to be  determined as a standard
necessary to satisfy the environmental water quality  standards established in full
consideration  of various factors and  their mutual relation, etc. The environmental
standards at Lake Biwa and its outflow, the Seta River are as shown in Table 9.3
     Table 9-3     Environmental Water Quality Standard at Lake ESwa and Seta River
Lake fiwa
Northern Lake
Southern Lake
Seta Kiver
(Outflow)
pH
6.5-8.5
6.5-8.5
6.5-'8.5
COD
mg/1
less than
1.0
less than
1.0
less than
1.0
SS
mg/1
less than
1.0
less than
1.0
less than
25.0
DO
mg/1
more than
7.5
more than
7.5
more than
7.5
Coli. Counts
MFN/100 ml
less than
50
less than
50
less than
1000
Target
Date
*
1977
*
                   *  Immediately satisfied after issued standard in 1972
     As mentioned in the preceding chapter, the value of COD at Lake Biwa is much
greater  than that of environmental standard, 1  milligram  per  liter, in both  the
northern and southern parts. Especially during the summer period it stands at 2 to 4
milligrams  per  liter.  In order to achieve this environmental standard  at the earliest
possible time, it is in urgent need  to reduce the pollution load. On the basis of the
data about  the self-purification, the dilution, and the diffusion the actual effluent
quality standard  should be set up. Then required waste water treatment process will
be designed. The environmental standard  and the effluent quality standard on pho-
sphorus and nitrogen are scheduled to be  established in the near future although the
present standard says nothing oth them.
     Thus,  to prevent the eutrophication,  the nutrients should be removed in nearest
future. It is said that ferric salts, vitamins and carbonate  also have relations with the
eutrophication  beside from  nitrogen and phosphorus, but as of now the requisite in-
formation is insufficient. In general, nitrogen and phosphorus are considered to be
the limiting factors of the eutrophication.
                                      325 -

-------
    The result of a study on the limiting nutrients at Lake Biwa by means of the AGP
Method is shown in Table  9.4  According to this result, since even at the same
point of Lake  Biwa nitrogen plays a role of the limiting factor in one season and
then phosphorus takes its place in another season, it is considered that there exists a
variation depending on the geographical conditions, the kinds of pollution and the
meteorological  conditions, etc. in the lake.
              Table 9.4  Restrictive Factors of the Growth of Algae

Hikone (Northern Part)
Yabase (Southern Part)
Seta River (Outflow of
Lake Biwa)
Zeze (Southern Part)

August 1973 October
October
June Augus
August
June
August
January 1974
October 1973
Phosphorus
•
•
•
0
•
0
0
•
Nitrogen
o
o
o
•
•
0
•
o
       •  Stimulate the growth of algae
       o  Does not stimulate the growth of algae
Accordingly, it will be known that the removal of both nitrogen and phosphorus is
desirable for the complete control of the eutrophication. However, due to the ex-
istence of bacteria and algae (blue-green algae) which fix it from the air, it is difficult
to control the nitrogen efficiently. Hence, studies were herein conducted before
everything on the removal of phosphorus.
     Now,  there arises a question; to what extent the concentration of phosphorus
in the effluent water  from a sewage  treatment plant should be lowered? This ques-
tion can be answered rather easily if the AGP is applied.
     By  changing alum  dosage, effluents which  contain several concentrations of
phosphorus are prepared. Then the effluents are  dilluted with the least eutrophicat-
ed  lake water at a certain ratio, say  20 times. When AGP is related with the phos-
phorus concentration in the prepared effluent, allowable maximum phosphorus con-
centration  would  be  determined.  Fig.   9.4 shows the results  of the examination.
     As is shown in the  figure, when an amount  of either alum or ferric chloride is
dosed  to reach its concentration of 100  ppm, AGP in the mixture is always kept less
than  20 mg/1.  For this circumstance,  phosphorus concentration in the  prepared
secondary effluent is 0.03 mg/1. Judging from this result,  it is considered that the
eutrophication in  the lake water may hardly be  promoted if PO4-P as the tertiary
treatment water is set at lower than 0.03 to 0.02 milligram per liter.
                                    -  326  -

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9.4   REMOVAL OF PHOSPHORUS
9.4.1   BACK  GROUND
    For the purpose of phosphorus removal from urban sanitary sewage, technical-
ly and economically feasible processes are the following
    a.  Luxury biological phosphorus uptake process
    b.  Coagulant dosing process
    c.  Lime  precipitation process
    d.  Alum precipitation process
It was reported that if the luxury uptake process was successfully operated, over 80
percent of the total  phosphorus could be removed.  However it is not easy or not
always possible to keep the process  at the  optimum condition.  Sometimes the
process may be of success in the luxury uptake but sometimes not.
    By means of dosing  coagulant to an aeration  tank, the phosphorus  removal
through the secondary treatment process improves considerably. At first we  believed
that this was  an  economical  way to grade up the present  facility. We  tried to
examine performance of this process on a pilot plant. When three times aluminum in
mol ratio to phosphorus were dosed to the aeration tank, about 60-80 percent of the
phosphorus existed in inflow sewage were precipitated. If this amount of alum was
added, its concentration in the mixed liquor would be about 150 mg/1. Even though
such the high  dosage as 150 mg/1, the secondary effluent still contained 0.2 ~ 0.5
mg/1  of phosphorus. This concentration was  not satisfactory for the  Biwa  Lake
water. Higher phosphorus removal required more alum dosage. A new problem rised;
that was retardation of biological activity. Too much alum in the biological process
resulted in poor  BOD removal. Thus, we  quitted  this process and came to the
decision that  an  independent  advanced plant should be placed  to  cope with the
phosphorus problem.
    The most popular and effective coagulant for this purpose is lime.  Sludge pro-
duced from the  lime precipitation  process  can be easily dewatered  by ordinal
devices. This  is one of the important advantage in selecting any unit processes.
Disadvantages  being associated with this process are difficulty in handling lime, and
scaling in pipes.
    The alternative is the alum precipitation process. For the phosphorus  removal
alone, alum is as effective as lime. Alum is easy to handle and is not scaling. However
on the other hands, alum sludge is hard to dewater.
    Finally we came to the conclusion that the alum process was selected for the
case of Lake Biwa's tertiary  purpose. It is not because we like the advantages of the
alum  process more, but because we like the  disadvantages of the lime process less.
There was no news of success in dewatering sole  alum sludge. Development of sludge
dewatering engineering and establishment of design parameters for the alum process
were the next  step to approach the final goal. This was a story untilthis pilot plant
was placed in Otsu sewage plant.
9.4.2   PILOT  PLANT FOR PHOSPHORUS REMOVAL
    A flow sheet of the pilot  plant is shown in Fig.  9.5 The hydraulic capacity is
500 cubic meters  per day. In this flow rate, design detention time is 15, 30,  and 150
                                      327

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                                                         Fig. 9.5  Flow Diagram of Coagulation Process
INJ
OC
                   Influent
                                                                 Flush mixer tank

                                            Measuring tank        /       \
                           Floculation
                           tank
                Settling tank
                          Receiving tank
                                    Coagulant
                                    injection
                                    pump
Poliner injection pump
Sludge return
pump
                       Coagulant storage
                       tank (Alum.)
 Polimer
 storage tank
                                                  Sludge
                                                  pump
                                                                                  Dewatering
                                                                                  process
                                                                                                 Sludge thickner tank
Effluent holding
tank

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                               Fig. 9.6  Flow Diagram of Sludge Handling Process
     Inflow
Sludge
thickner
tank
                            Coagulation dissolve tank
                                                Handling tank

                                                           Coagulant pump
                                                           O
                               Handling tank             Sludge pump
                                                                                     Centrifuge
Land disposal
                                                                               Supernatant          Dewatermg
                                                                                                   sludge hopper

-------
minutes for the rapid  mixing tank, the flocculation tank,  and precipitation tank
respectively.
     Into the center of the rapid mixing tank,  liquid alum and polymer are fed at a
certain rate through chemical feeding pumps.  A small amount of the polymer is
helpful with alum flocculation.
     In order to save the alum, some portions of the precipitated alum sludge are to
be returned from the precipitation tank to either the rapid mixing tank or the floc-
culation tank.
     In future, automatic control  system will be introduced  so that the alum can be
dosed proportionally to phosphorus concentration. Thus, we will be able to examine
several aspects on the automatic control practice.

9.4.3 PHOSPHORUS  REMOVAL
     In general, a large plant requires much more alum that of theoretical requirement
due to improper design. Our main concern is to  find the optimum process conditions
under which phosphorus can effectively be removed by a  small  amount of alum
dosage. Up to the present, it is found that when alum is dosed as much as 13.6 mg/1
(or mol ratio to phosphorus 5  to 1) about 90 percents phosphorus are removed.
     The pilot study is now under ways for the  purpose of finding:
(1)  A relation between sludge producing rate and alum dosage
(2)  a relation between SS removal rate and alum dosage
(3)  effect of return sludge on phosphorus removal and on alum saving
(4)  optimum rapid mixing and slow mixing
(5)  polymer dosing rate and dosing point.

9.5   SLUDGE  HANDLING
9.5.1  ALUM SLUDGE
     An increase in alum  dosage  results in an  increase in phosphorus  removal. We
can  cope  with any  requirement for high phosphorus removal.  Removing  the
phosphorus in  a rather easy job. One of the  big  problems included  in the alum
precipitation is that a large amount of sludge  is produced.  The amount is directly
proportional to the alum  dosage. Through the course of  the present pilot alum
process, in every 500 cubi: meters influent, 3.4 cubic meters sludge are produced.
Therefore when 1 million  cubic meters raw sewage is treated in  the  actual plant,
daily sludge production rats will be 7000 cubic  meters. A special attention should be
paid to  this large number. A success in phosphorus removal from Otsu's effluent
will be entirely dependent  on the sludge handling capability.
     The kinetics for the alum precipitation process is not yet completely clear. It
seems probable  that two  reactions may be  concerned  with this process; (1) alum
combines  directly phosphorus and forms floes of aluminum phosphate, and (2)
phosphorus is absorbed at the surface of aluminum hydroxide  which is  formed
through a reaction between the alum and alkalinity.
     Phosphorus (total-p) concentration in the secondary effluent from the present
Otsu sewage plant is as low as 1  mg per liter. Suspended solid concentration ranges
from 3 to 5 mg per liter. Volatile solid contents are about  35 percents of the total
suspended  solids. This means that  large  portion  of the   precipitated  sludge  is
                                      330

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aluminum compound.

9.5.2  THICKENING
     Underflow concentration in the precipitation tank is no greater than 5000 mg
per liter.  The sludge is very  hard  to  thicken; under the quiescent condition, by
gravity, during 24 hours,  an increase in solid concentration is about 30 or 40 per-
centration never exceeds 10000 mg per  liter by the gravity thickening method.

9.5.3  DEWATERING
     The solid particles in the sludge are very  fine and they stay as soil or gell in it.
Leaf tests do not show any  capability  for vacuum filters to dewater the sludge. It is
observed that the fine particle included in the alum sludge pass through the filter
cloth when  a Buchner funnel test is performed. Magnitude of the drainability or
filterbility can not be determined in the laboratory Buchner funnel test.
     We give up examining possibilities  of success in dewatering by using the vacuum
filter. Our interests are shifted to centrifuge dewatering. It may be the only device
which has possibility to yield satisfactorily moistured sludge cake from alum precipi-
tant.  Meanwhile,  our  laboratory research shows that if  the polymer is  properly
selected and properly dosed, a certain  centrifuge will do the job. Polymer  is a very
important factor  to affect centrifuge performance.  Our staffs moves up from  the
laboratory to the field where  the pilot plant is located. Fig- 9.6 is a flow  sheet of
the plant. The dewatering study continues with this plant now.
     The findings are summerized in Table 9.5. The tests from run # 1 to # 5 are
for selecting most suitable polymer and those from # 6 to # 9 are for optimum ope-
rational conditions of the centrifuge.
     The design specification of the pilot centrifuge are as follows;
Maximum Power                         3200 G
Maximum Revolution Speed              6000 RPM
Motor Output                           3.75  KW
Capacity                                500 liter/hr.
     The folio wings are concluded from the pilot study:
(1)  More than 96 percents of the suspended solid are recovered and moisture con-
centration in the  dewatered sludge cake is 90% at average, (85% at minimum). The
dewatered sludge can sustain own shape by itself on a flat plate. This can be handled
by hands or  a shovel easily.
(2)  An increase  in the polymer dosage rate does not improve the moisture  concent-
ration. On the basis of dry solids, 0.5 percents are the optimum dosing rate.
(3)  If the  sludge feeding rate is increased, the moisture concentration in the de-
watered sludge is  kept fairly constant value, 90%, and the SS recovery rate is decrea-
sed. The same is observed when difference of revolution speeds between the bowl
and the conveyer  is increased.

(4)  Whether cathionic or anionic is not an important factor. The effectiveness of
the polymer is not dependent of its ion  charge.
                                     331

-------
(5)   Solid concentration of the  fed  sludge is  a main factor on the centrifuge per-
formance. The thicker is the fed sludge, the less is the moisture contents of the de-
watered sludge.
(6)   With lower bowel dam height in the centrifuge than with higher, less moistured
sludge  are yielded. The pilot centrifuge is  designed  to adjust  the dam height at 4
levels.  With  the lowest level of the dam, least  moistured sludge are produced. It is
around 85 percents.
     The value of 85 percents moisture concentrations in the dewatered sludge is
not perfectly satisfactory.  Our efforts will be concentrated at reducing the number
to about 80 percents. Selection of proper polymer is a way  to approach the purpose.
Another way is to stimulate manufacturers to provide  a proper centrifuge.
     One of the important thing that we should know is how Acrylamid, main com-
ponent of the polymer, affects  the environment. When supernatant is returned  to
the secondary process, at  present moment,  we are not sure what happens with the
secondary effluent. We are going  to examine bio-degrability of the polymer returned
to the aeration tank.
     Commonly it is reported that  alum  recovery  is not  economically  feasible.
However,  from the stand point of natural resource saving, our interests are still kept
on developing the  alum recovery engineering. Sulfic acid process could be in higher
potential.
                                    -  332

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                                                   Table 9.5   Summary of Sludge Dewatering Performance
Test
No.
1
2
3
4
5
6
7
8
9
Spec, of Machine
Revolution
(r.p.m)
5000
5000
5000
5000
5000
5000
5000
5000
5000
Dam
No.
4
4
4
4
4
4
3
3
3
Revolution
Difference
(r.r.m)
6
6
6
6
6
10
6
6
15
Influent
Density
(%)"
0.6260
0.6230
0.4800
0.6970
0.6770
0.6200
0.9190
0.9740
0.8810
Sludge
loading
(1/hr)
400
400
400
400
400
400
500
500
700
Solid
loading
(kg/hr)
2,505
2,490
1,921
2,788
2,732
2,480
4,595
4,870
6,167
Filtrate
Density
(%)
0.0245
0.0220
0.0136
0.0146
0.0090
0.0450
0.0113
0.0084
0.0300
SS
Recovery
ratio
96.09
96.47
97.17
97.91
98.67
92.74
98.77
99.91
96.59
Moisture
(%)
90.07
89.95
88.79
89.21
89.36
90.79
88.14
86.82
88.54
Coagulant
Density
(%)
0.05
0.05
0.05
0.05
0.05
0.05
0.10
0.05
0.10
Volume
(1/hr)
30
55
34
31
31
30
17
80
56
FA/SS
(%)
0.600
1.105
0.916
0.556
0.568
0.6048
0.3680
1.643
0.908
Sort
A
B
C
D
E
A
B
C
B
U-l
 I
                        A:    N0-75°(nonion)
                        B:    A-101  (anion)
                        C:    N-800  (nonion)
                        D:    SS-200 (nonion)
                        E:    C-OllK(cation)

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9.6   FURTHER  RESEARCH NEEDS

9.6.1   LOADING  OF  PHOSPHORUS  AND  NITROGEN  ON  LAKE  BIWA
     Kinki Branch  Office of Ministry of Construction conducted intensive study on
nutrient loading on Lake Biwa in the last year as shown in Table 9.6 and 9.7.

                       Table 9.6  Total Phosphorus Loading*

Domestic Waste
Water
Industrial Warte
Water
Warte-water from
eivestock Yard
Discharge from
Pady Field
Discharge from
Frest etc.
Total
1970
Load (kg/d)
174.0
21.6
32.8
40.3
66.3
335
Share (%)
51.9
6.4
9.8
12.0
19.8
100
1980**
Load (kg/d)
247.5
125.6
74.3
41.9
66.3
555.6
Share (%)
44.6
22.6
13.4
7.5
11.9
100
                         Table 9.7  Total Nitrogen Loading*

Domestic Waste-
water
Industrial Waste-
water
Waste-Water
livestock yard
Paddy field
Frest
Total
1970
Load (kg/d)
1960.5
801.5
111.5
974.6
1264.9
4713
Share (%)
33.1
17.0
2.4
20.7
26.8
100
1980**
Load (kg/d)
1854.5
1974.9
244.6
1181.8
1264.9
6520.7
Share (%)
28.4
30.2
3.7
18.1
19.4
100
      *(1)   Table does not include load from well water source because of
            uncertainty of measurements.
       (2)   This figure are projected before treatment.
      **     This is estimated based on economic development plan of Shiga Pufectural Govern-
            ment.
                                      334 -

-------
The water quality of lake Biwa at present are mentioned before, it will be expected
that  nutrients loading exceed  a certain amount very much such as critical or dan-
gerous level as proposed Vollenweider.  The rate of effluent to total discharge of
Lake  Biwa to downstream is around  10%,  so it is very important  to remove the
phosphorus to protect lake water.
Unfortunately available data are very scarce on water quality, flow pattern, diffusion
characteristies and budget of nutrients in the lake, much research works are needed
in this fields.
9.6.2 FURTHER PILOT  PLANT  STUDY
     Pilot plant study for Lake Biwa is 4 Years project, then it will be completed in
 1978.  First of all, removal of phosphorus by alum precipitation are  examined, and
 dewatering of alum sludge are found   to be possible by centrifuge.  All possible
 alternatives to remove nutrients from  wastewater should be projected to examine
 including cost effectiveness study in this project.
Reference.
 1)   J.S.W.A. Survey on the Pollution in Lake Biwa in 1972, 1973.
2)   An Approach to a Relative Trophic Index  System for Classifying Lakes and
     Reservoirs, Working Paper No. 24. Pacific North West Environmental Research
     Laboratory U.S. EPA.
                                    -  335  -

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                             Fourth US/JAPAN Conference
                                       on
                             Sewage Treatment Technolgy
                                Paper Annex to No. 4
CASE  STUDIES  ON PCB POLLUTION
             October 29, 1975
             Washington, D. C.
          Ministry of Construction
           Japanese Government
                      336 -

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CASE STUDIES  ON  PCB  POLLUTION  (CONTINUED)
                    - 337

-------
2.2  CASE STUDIES ON PCB POLLUTION (continued)

    Environmental pollution  of PCBs  was  first  recognised in
Europe followed by the United States then Japan.     Results of
field investigations demonstrated that PCB pollution  in organ-
isms inhabiting the natural environment was at a^evre level.
In Japan, analytical results indicating concentrations of resi-
dues in trild animals were first reported in 1971.    In January
of 1972, a standard method for the analysis of PCBs was establ-
ished by the reseaoh group of the Ministry of  Health and  Wel-
fare, whereby the uniform analysis of PCB residues in wild ani-
mals was realised.
                        71.
    A national survey Governing environmental pollution of PCBs
was conducted from May to December, 1972.   During this period,
the water quality of 1,084 locations and bottom sediments samp-
led from 1,445 places was inspected.   Canvassing the agricult-
ural industry, PCB analysis were carried out for samples     of
soil and rice taken from 88 locations throughout the   country,
while similar analysis were conducted for 559 samples of  fish-
eries products taken from 110 aquqtic regions.     Summaries of
these results are shown in Table 4» 5 and 6.     Prom  1973  to
March, 1974, l,28l samples were collected from 282  aquatic re-
gions for water quality analysis (208 rivers; 28 harbours;   46
ocean regions), while 1,7^9 samples of bottom sediments    were
collected from 354 aquatic regions (258 rivers; 38 harbours; 58
ocean regions) as well as 3,369 samples representing    aquatic
biota.
    In Japan, the accumulation of PCBs in the human body can be
surmised and evaluated on the basis of analytical  results   of
residues detected in human milk.   Such a survey was      taken
throughout the country during the three year period from   1972
to 1974» and the results are summarised in Table 7,   A summary
of regional differences based upon the results of the 1974 sur-
vey is presented in Table 8, and indicates that the PCB content
                               338

-------
of human milk tended to be highest in those regions   described
primarily as fishing villages and lowest in farm inhabitants.

 Table 4  Results of the Survey on PCB Pollution (Water Quality
          and Sediments)
PCB
content
(ppm)
Industr-
ies
using
PCB
Sewage
treat-
ment
plants
Waters




nearby
factor-
ies
Public
Waters
Total


Water Quality
0.01 0.01
or or
less more
78 13
125 0

76 4

785 3
1,064 20



Sub-

91
125


80

788
1,084


Sediments
1 1.1 11 51 100 500
or S S S * or
0 19 10 5 11 9
------
26 24 15 7 1 4
1,216 73 20 2 3 0
1,242 116 45 14 15 13
Sub-
total
54
-
77
1,314
1,445
Grand
Total

145
125


157

2,102
2,529
 Table 5  Results of the Survey on PCB Pollution (Soil and
          Agricultural Products)
PCB Concentration

less than 0.01 ppm
0.01 0.10 ppm
0.11 1.0 ppm
1.1 10.0 ppm
10.1 100.0 ppm
more than 100.1 ppm
Total
Number of Soil
Samples
35 ( 40$
21 ( 24$
19
6
3
4
21$
7$




3$)
5$)
88 (100$)
Number of Unhuller".
Rioe Samples
26
5
1
1
79$
15$
3$
•jrg







                               339

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Table 6  Results of the Survey on PCS Pollution
         (Fisheries Products)  (1972)
PCB
Concentration
(ppm)
Sea Water
Fresh Water
Total
0.09
or
less
(34)
155
(15)
21
(30)
176
0.1
S
0.4
(38)
175
(44)
63
(40)
238
0.5
5
0.9
(12)
53
(23)
33
(14)
86

1-2

(11)
48
(13)
19
(11)
67

3

(2)
11
(1)
2
(2)
13
more
than
3
(3)
14
(4)
5
(3)
19

Total

(100)
456
(100)
143
(100)
599
Table 8  Frequency Distribution of PCB Concentration in Human
         Milk in Urban,  Agricultural and Industrial Eegions(l972)
Concent-
ration
(ppm)
0.009
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.1
0.2
Total
Mean
Median
Total
(Cumulat-
ive %)
67( 12.1)
86( 27.5)
148( 54.1)
90( 70.3)
77( 84.2)
33( 90.1)
14( 92.6)
25( 97.1)
6( 98.2)
4( 98.9)
6(100.0)
-
556
0.028
0.023
Urban
Residential
Areas
22
37
74
41
36
15
6
8
3
-
2
-
244
0.028
0.024
Farm
Villages
34
31
49
23
23
6
5
2
1
1
1
-
176
0.023
0.020
Fishing
Villages
8
13
17
22
15
7
3
11
2
3
3
-
104
0.037
0.031
Industrial
Vicinities
3
5
8
4
3
5
-
4
-
—
-
—
32
0.031
0.025
                            340

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                   PLANNING FOR URBAN RUNOFF CONTROL UNDER COMPREHENSIVE
                              WATER QUALITY MANAGEMENT SYSTEM

                                     Walter S. Groszyk
                         Deputy Director, Water Planning Division
                              Environmental Protection Agency
                               East Tower, Room 815 - WH-554
                                    401 M Street, S.W.
                                  Washington, D.C. 20460
                                         ABSTRACT
                                                                               (
     This paper summarizes the approach being developed by the U. S. Environmental
Protection Agency for the abatement of urban storm runoff.   The approach features the
development, at the local or regional level, of specific management practices to
control runoff.  These practices emphasize non-capital intensive methods of minimizing
the pollutant loading of runoff and are formulated through a comprehensive areawide
planning effort that assesses the dimensions of the runoff problem, the water quality
effects, and abatement needs.
                                           TEXT
     The United States Environmental Pro-
tection Agency through the States and
cities conducted a survey of the estimated
construction costs to abate storm sewer
pollution.  This survey of needs amounted
to nearly $250 billion in current dollars.
While the number does not generally reflect
any engineering plans or detailed surveys,
its rough magnitude is staggering and
beyond the digestive capacity of the Fed-
eral budget.  There is simply no foreseeable
way that the Federal Government would be
able to finance a construction program of
this size for this problem.  It exceeds by
tenfold the total program of landing a man
on the moon, and is nearly ten times the
total annual contract construction value in
the U.S. gross national product for 1973.
As an additional perspective, the estimated
costs, in this same Needs Survey, for con-
structing treatment plants, interceptor and
collection sewers, and controlling combined
sewers totalled approximately $100 billion,
with the total need becoming nearly $350
billion.

Areawide Planning

     Under the Federal Water Pollution Con-
trol Act,  an areawide planning program is
to be conducted in urban-industrial areas
with significant water quality problems.
This planning program has just begun, and
at the present time planning is under way in
149 areas at a cost of $163 million.  This
planning covers many of the largest cities
of the United States, including New York,
Philadelphia, Chicago, and Detroit.  These
plans will eventually cover the entire
United States.  Presently, about 45% of
the population and 11% of the land area
of the United States are covered by area-
wide, planning.

     Areawide planning is also called 208
planning, after the number of the section
of the Federal Water Pollution Control Act
which authorizes it.  Areawide planning is
quite unique for three reasons.  It is
expected to be the largest planning pro-
gram ever funded by the Federal Government;
all the financing for the program comes
from the Federal Government; and the law
requires that the plans be implemented.

     Areawide planning conducted for a local
area is a comprehensive plan.  The plan
covers both point and nonpoint sources of
pollution.  It includes:  initial facilities
planning for municipal sewage treatment
works; an identification of industrial pol-
lution control requirements; and the
                                           629

-------
identification of practicable methods and
procedures for the control of nonpoint
sources of pollution, including runoff from
agricultural, silvicultural, mining, and
construction activities.

     The planning effort is conducted at
the city and county level, and is under the
direction of the chief elected officials of
local government within the planning area.
This will assure that plan development
reflects the views of the government
officials who will operationally implement
the plan.  The initial plan is to be comp-
leted not later than three years after the
planning agency has been approved by EPA.
At the time of completion, EPA is required
to approve the designation of the manage-
ment agencies who will carry out the plan.
The planning agency continues to function
and develops revisions to the plan as they
are required.

     This stress on locally originated
planning conducted under the direction of
locally elected officials reflects an
appreciation that levels of abatement more
stringent than those required by nationally
applicable effluent guidelines for industry
or uniform secondary treatment for munici-
palities can often best be addressed by
examining the specific pollution problems
in that area which remain after national
levels of control are applied; assessing
the institutional and financial capabili-
ties that exist or can be developed to
abate the sources of this remaining pollu-
tion; and then making the tradeoff's
between alternative control methods to
develop the most effective and reasonable
way of reaching the water quality
objectives.

Best Management Practices (BMP's)

     The Environmental Protection Agency,
to assist planning agencies in making these
tradeoff's,  is developing informational
guidelines outlining different methods and
procedures that can be used to abate non-
point source pollution including urban
runoff.  These informational guidelines are
called Best  Management Practices or BMP's.
A BMP is not an "end of the pipe" techno-
logical control level, but rather is a way
of doing business.   It is directed to the
activity being conducted;  as an example,  it
may indicate that sediment runoff from a
farmer's field can be reduced by changing
the manner in which the farmer plows the
 field.  BMP's are being  developed  for all
 categories  of nonpoint source  pollution,
 including urban runoff.

     BMP's  for a particular  category
 present an  array of  alternative  practices
 with varying economic costs  and  efficiency
 rates.  The practices often  identify cli-
 matological or topographical suitability.
 From this inventory  of BMP's we  expect the
 planning agencies to select  those  practices
 which most  fit the abatement needs of their
 area.  The  planning  agency is  not  required
 to use any  of the BMP's  but  may  develop an
 equivalent  BMP on its own.   While  Best
 Management  Practices are generally con-
 cerned with non-capital  intensive  methods
 of control, they are not exclusively so.
 A planning  agency may also,  after  analysis,
 determine that the most  effective  and
 economic way to achieve  water  quality goals
 for that area is through the construction
 of facilities and structures.

 BMP's and Urban Runoff

     Our present perception  is that  it is
 neither necessary nor possible to  treat all
 storm waters.  A receiving water is  subject
 to stresses caused in part by various
 natural and uncontrollable occurrences.
 Many streams experience  difficulty during
 the low flow and high temperature  period
 of later summer.   Wet weather conditions
 represent yet another period of  stress.

     The true extent of  the  storm  water
 problem is  largely unknown and the lack of
 any extensive historical studies or  con-
 cern makes  it difficult  to characterize.

     Considering the area and route  that
 urban runoff takes, it is not surprising
 that this runoff contains substantial
 amounts of  organic material, inorganic
material, inorganic solids,  nutrients,
 heavy metals and micro-organisms.   The
 impacts from this runoff are often
 increased oxygen demand, high  turbidity,
 and increased eutrophication rates.   Addi-
 tionally, the impact of  heavy metals  on the
 aquatic environment has  to be considered.

     The total pollutant load in storm-
water, during storm runoff periods,  can be
 greater than the pollutant load  discharged
 from municipal treatment plants  during dry
weather.  This could preclude meeting  water
 quality standards regardless of  the  degrees
 or types of treatment afforded dry weather
                                           630

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wastewater flows.

     Related problems resulting from
unregulated, or poorly regulated, runoff
are accelerated erosion of land area and
stream banks, sedimentation of channels,
increased flooding, increased potential for
public health problems and deterioration of
aesthetic quality.

     Assessing the impact of stormwater run-
off is not easy.  Part of the difficulty
lies in the variability of stormwater run-
off.  The quantity and quality of storm
overflows, for example, can vary with
respect to storm characteristics, antecedent
conditions, time, location, degree of urban-
ization and other factors.  This variability,
the differing problems in new and expanding
urban areas compared with existing areas,
and the scarcity of information concerning
stormwater impact on receiving waters pose
challenges to the formulation and admin-
istration of an effective management program.

     Some of the examples of these varying
factors are that:  loading rates are lowest
in commerical areas; BOD 5 and COD concentra-
tions are lowest in residential and heavy
industrial areas, while the COD concentra-
tion is highest in commerical areas; cadmium
concentrations are relatively uniform across
all areas; chromium, nickel, and copper are
lowest in residential areas, with lead con-
centrations lowest in heavy industry areas;
and finally, and surprisingly, there is no
significant difference between land use
category and fecal coliform count.

     From the analysis of the specific prob-
lem parameters with respect to water quality
and with a correlation as to the likely land
use areas and the sources of the problem,
the planning agency can then analyze which
BMP's it might apply to control the problem.

     BMP's within an urban/suburban area
include source regulation, collection system
control, treatment, and an integrated
approach using all three.  Source control is
defined as those measures for preventing or
reducing stormwater pollution that utilize
management techniques (e.g., good house-
keeping methods) and stormwater detention
within the urban drainage basin before
runoff enters the sewerage system.
Collection system control includes all
alternatives pertaining to collection
system management, such as use of sewers as
detention facilities.  Treatment, including
storage, is another technique.  The term
storage refers to stormwater being retained
for the purpose of treatment as opposed to
storage used in source control to attenuate
the rate of runoff.  Flow attenuation is
concerned directly with runoff as it moves
over the surface of the urban area; i.e.,
the initial collection system.  Flow attenu-
ation, in an hydrologic sense, means to
increase the time of concentration and
decrease the magnitude of the peak runoff.
In terms of water quality this means that
runoff velocities are reduced and less pol-
lutants are entrained.  Also, less erosion
results because reduced runoff velocity
reduces the erosion force.  Moreover, large
volumes of water are not allowed to rapidly
accumulate at constrictions, but flow at
reduced rates over a longer period of time,
thus reducing the possibility of localized
flooding. An integrated approach might
include source control to help reduce pol-
lutant loads and runoff rates; collection
system control (sewerage) to reduce infil-
tration and to attenuate the runoff; and
treatment as a final stop where required
to meet water quality objectives.

     The management goals become:

     1.  Prevention and/or reduction of
         pollution.

     2.  Detention or retention of runoff.

     3.  Treatment of runoff.

     An additional goal that should not be
overlooked is reuse of stormwater runoff.
Reuse of stormwater places urban runoff in
the resources category.  It should be con-
sidered in those areas that can benefit from
groundwater recharge and supplemental sup-
plies for both potable and nonpotable use.

     The goal of the planning approach is
to provide sufficient pollutant reduction
to meet water quality objectives at a
minimum cost.  BMP's for urban runoff
should stress source and collection system
management, and reuse where applicable.
Treatment should be resorted to only when
all other lower cost methods have  failed  to
provide sufficient pollutant reduction.

     Urban runoff management should
initially emphasize the new urban  areas.
These new areas include land that  is  in  the
process of becoming urbanized.  These  are
areas  that allow for  the  greatest  degree  of
                                            631

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flexibility of approach in addressing the
long-term problems.  At a minimum, urban
runoff pollution must be contained to pre-
sent problems.  Once contained, then
emphasis can shift to problems associated
with existing areas.  Of course, for this
approach to be effective, complete area
coverage is required and the approach
should be implemented as appropriate
throughout the entire planning area.

     For a BMP to be considered as a best
management practice, it must meet certain
general and specific criteria.  Factors
that need to be addressed within a BMP
include, but are not limited to, the
following.

     A BMP must be compatible with the
hydrology and meteorology of the planning
area.  The frequency, intensity, duration,
and surface area extent of precipitation
must be addressed; also, infiltration
rates, depression storage, and runoff
rates.  Groundwater must be considered in
relation to recharge areas and levels, and
effect on stream channels fed from ground-
water.

     Runoff from snowmelt in some areas of
the country (for example, in parts of the
West) produces the major portion of the
annual runoff.  An important factor in
considering snowmelt is the temperature.
Other factors to be addressed are wind and
humidity.

     Topography, of course, is a factor
that must be  considered.  A BMP must be
compatible with the slope, length of basin,
and type of surface cover of the planning
areas.

     Geology  is another factor to be
addressed.  Soil types vary widely across
the country.  A BMP must consider and be
compatible with this variable.

     The specific examples of BMP's that
can be examined are to be considered as
being site-specific and are not to be con-
strued as being applicable nationwide.

     Source Control

     Some examples of source control are:

     1.  Street sweeping or control
         through housekeeping.
      2.   Sewer  flushing  to  reduce first
          flush  effects.
      3.   Detention  basins.

      4.   Rooftop  storage  and  parking
          lot  storage.

      5.   Porous paving, to  increase
          infiltration.
     Collection  System  Control

     Some examples  of collection system
control are:

     1.  Use of  existing  sewerage as
         detention  facilities.

     2.  Use of  swirl concentrators.
     Treatment

     Two examples which have been  studied
and have been found feasible for storm-
water treatment are:

     1.  Micro-straining with air
         floatation.

     2.  Contact stabilization.

     Institutionally, we expect the
planning process will work in the  follow-
ing manner.

     The planning agency staff will assess
the magnitude and extent of the urban pol-
lution problems.  These will be presented
to the public and any advisory groups to
ensure that a basic understanding  of the
problems is shared by all.

     The staff will then formulate water
quality goals based on protecting  bene-
ficial uses of water.  These will  be
discussed with the public and will be
presented to the advisory committee.  The
advisory committee overseeing the  develop-
ment of the plan will select the approach
which best meets the goals.

     Proposed criteria for controlling
urban runoff pollution will be prepared
by the staff in consultation with  the
public.  An inventory of alternative BMP's
which meet the proposed criteria will be
made.
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     The staff will evaluate and make
initial selection of those BMP's which
meet the water quality objectives, and the
public and advisory group will decide which
of the BMP's are institutionally and
economically acceptable.  Final selection
of the BMP's will be made then by the staff.

     After the urban runoff problem has
been assessed, runoff reductions to help
meet target load allocations achieved by
the use of BMP's often need to be trans-
lated into ordinances or regulations.

     Within EPA, we believe the use of the
areawide planning process together with the
systematized assessment of BMP's offers an
attractive alternative to total reliance
on capital facilities for control of urban
runoff.  The planning process has just
begun, and we would like to report at a
future conference on the results from this
effort.
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                        CONTROL  OF WATER POLLUTION THROUGH ISSUANCE OF
                       DISCHARGE PERMITS,  IMPLEMENTATION OF P.L.  92-500

                                        R.  B.  Schaffer
                                 Director,  Permits  Division
                                     Office of Enforcement
                             U.S. Environmental Protection Agency
                                   Washington,  D.  C. 20460
       OBJECTIVES OF THE NPDES PROGRAM
     On October 18, 1972, the Amendments to
the Federal Water Pollution Control Act es-
tablished the National Pollutant Discharge
Elimination System (NPDES).  With the enact-
ment of this new legislation Congress has
stated that it is the National goal that
the discharge of pollutants into navigable
waters be eliminated by 1985.  As an interim
goal it is stated that there be attained by
July 1, 1983, water quality which provides
for the production and propagation of fish,
shellfish and wildlife and provides for the
recreation in and on the water.

     Any permit issued under the National
Permit System will impose on a discharger
of pollutants from a point source certain
requirements designed to attain the goals
of the Act.  Every discharger must make
application for a permit and in so doing,
provide the permitting authority with data
on the discharge.  Each issued permit will
meet effluent limitations, wate?: quality
standards, new source performance standards
for new plants, and toxic pollutant stand-
ards.  Facilities discharging into a muni-
cipal waste treatment facility do not re-
quire a discharge permit, but the discharger
must comply with pretreatment standards
promulgated under the Act.  Permits will
require the discharger to monitor the dis-
charge, to keep records of monitoring ac-
tivities and report periodically on what is
occurring with regard to the discharge.

        THE EFFLUENT LIMITATIONS

     The new Act provides for uniform ef-
fluent limitations for industrial categories
and achievement dates.   Congress set two
interim dates of July 1,  1977 and July 1,
1983, by which different levels of treat-
ment are to be reached.   It is a timetable
based on advances in technology.
     For all discharges other than publicly
owned treatment works, not later  than  July 1,
1977, effluent limitations are to be achieved
which represent the application of the "Best
Practicable Control Technology Currently
Available."  At the same time, all publicly
owned waste treatment facilities must  uti-
lize ''secondary treatment" and, if an  indus-
trial discharger sends its waste  through a
publicly owned treatment works, certain "pre-
treatment standards" must be met.  An  addi-
tional requirement is that by the July 1977
date, effluent limitations may be imposed so
that any state law will be met.  Not later
than July 1, 1983, effluent requirements
must be met which represent the "Best  Avail-
able Technology Economically Achieveable"
and, for publicly owned waste treatment
facilities, which represent the application
of the "Best Practicable Waste Treatment
Technology.'1  Any other applicable pretreat-
ment standards must also be attained by that
date.  Special standards of toxic substances
must also be observed for both the 1977 and
1983 targets.

     The target dates are 1977 and 1983;
they are the outside limits for compliance.
The Act envisions that in meeting effluent
limitations there will be stages  of compli-
ance including attainment of levels of sub-
stantial improvement even before  these dates.
Therefore, most permits will impose a
schedule of remedial measures.  This sche-
dule will appear as a condition set out in
an NPDES permit.

     The Agency has requested authority to
extend the 1977 date on a case-by-case basis
for publicly owned treatment works.  However,
we do not feel it is necessary to extend  the
date for other dischargers nor do we expect
the National Commission on Water  Quality  to
recommend it to Congress.
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    BEST PRACTICABLE CONTROL TECHNOLOGY
       AND BEST AVAILABLE TECHNOLOGY
      The Act charges the Administrator with
 the task for publishing regulations provid-
 ing "Guidelines" for effluent limitations
 for point sources after he has consulted
 with the appropriate Federal and State
 agencies and other interested persons. These
 effluent limitations are the ones which
 shall require the application of the Best
 Practicable Technology by 1977, and Best
 Available Technology Economically Achieve-
 able for the 1983 target dates.  Two things
 will be identified in the regulations.

      First, they will give meaning to the
 terms "Best Practicable" and "Best Avail-
 able" when applied to various categories
 of industries.  In defining "Best Practic-
 able" and "Best Available" for a particular
 category, such factors as the age of the
 equipment and facilities involved, the pro-
 cess employed, the engineering aspects of
 the application of control techniques, pro-
 cess changes, and non-water quality environ-
 mental impact (including energy require-
 ments) will be taken into account.  In
 assessing "Best Practicable Control, a
 balancing test between total cost and ef-
 fluent reduction benefits is to be made.
 Cost is also a factor in determining "Best
 Available."  "Best Available" technology is
 the highest degree of technology that has
 been demonstrated as capable of being de-
 signed for plant scale operation, so that
 costs for this treatment may be much higher
 than for treatment by "Best Practicable"
 technology.  Yet economic feasibility will
 also be a factor in interpreting "Best
 Available" treatment.  Cost effectiveness
 for either standard is to be confined to
 consideration of classes or categories of
 point sources and will not be applied to
 an individual point source within a cate-
 gory or class.

     Second,  having interpreted "Best Prac-
ticable" and "Best Available" guidelines
will be published which will determine what
"Effluent Limitations" are to be imposed on
dischargers.   In these guidelines the degree
of  effluent reduction attainable through the
application of the "Best Practicable Control"
and "Best Available Technology" in terms of
amounts of constituents per unit of produc-
tion.   These guidelines can then be applied
in  setting specific effluent limitations on
dischargers.
     The Agency will promulgate these various
standards and guidelines for some 200 classes
and categories of dischargers.

   TOXIC POLLUTANT EFFLUENT STANDARDS
     The Act requires the establishment of
effluent standards or prohibitions controll-
ing toxic pollutants.  Toxic pollutants are
defined as those pollutants, or combinations
of pollutants which, after discharge and
upon exposure to any organism either directly
or indirectly, will "on the basis of infor-
mation "available" cause death, disease, or
other abnormalities in the organism or its
offspring.  The drafters of the Act had in
mine certain substances such as mercury,
beryllium, arsenic, cadmium pesticides, etc.

     A list of toxic pollutants has been
proposed.  Effluent standards for those
toxic pollutants listed will be published
later.

    NEW SOURCE PERFORMANCE STANDARDS

     Most new plants will be subject to
national standards for performance.  EPA is
to publish a list of categories of sources
which must include 27 major types of indus-
tries and then issue regulations establish-
ing Federal standards of performance for
the new sources within such categories.
These standards are to assure that new sta-
tionary sources of water pollution are de-
signed, built, equipped, and operated to
minimize the discharge of pollutants.  The
standards are to reflect the greatest degree
of effluent reduction which the Administra-
tor determines to be achievable through
application of the best available demon-
strated control technology, processes,
operating methods, or other alternatives.
"Best Available Demonstrated Technology" has
been described as those plant processes and
control technologies which, at the pilot
plant or semiworks level, have demonstrated
that both technologically and economically
they justify use in new production facili-
ties.

     At the same time EPA promulgates new
performance standards, it is to provide
pretreatment standards for newly constructed
point sources discharging into public treat-
ment facilities.
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         WATER QUALITY STANDARDS

     The new Act does not ignore the concept
of water quality standards in 19.77 and 1983
achievements.  Water quality standards which
were adopted and enforced under the old
Federal Water Pollution Control Act (FWPCA)
for interstate waters are continued in effect
and can be updated and the new ones are to
be established for intrastate water bodies
where not previously adopted by the States.
If water quality standards cannot be pro-
tected by the application of best practic-
able control technology for industries and
secondary treatment for municipal wastes
before 1977, then more stringent effluent
limitations are to be imposed which will
pro-tect water quality for public water
supplies, agricultural and industrial uses,
assure protection of a population of fish
and wildlife, and allow recreational activi-
ties.

          EFFLUENT LIMITATIONS

     The permit will contain one or more
sets of numerical limitations which must be
met by a date specified in an associated
compliance schedule.  In general,  the ef-
fluent limitations, with the exception of
pH, will be expressed in terms of  total
weight (Ibs/day or kg/day).   The effluent
limitations in the permit are described in
terms of daily average and daily maximum
values.  The limitations expressed in the
permit are based on promulgated effluent
guidelines, interim guidance or water
quality standards if more stringent limits
are necessary to protect water quality.  The
limitations or standards established by the
Agency are to be applied in a uniform manner
throughout the country.   The standards are
minimum technological requirements to be
applied even though the receiving  water may
not require that level of abatement to
achieve the desired water quality.

           COMPLIANCE SCHEDULE

     The compliance schedule will  specify
when final effluent limits must be attained
and may also contain dates for achieving
certain plateaus such as development of
engineering reports,  final plans,  beginning
of construction,  completion of construction
and the operation of facilities.   Interim
dates and requirements are to be specified
in the permit as a  means of  monitoring
progress  and minimizing slippage.   Following
each interim date,  the permitee must submit
 a written notice of compliance or non-com-
 pliance with the interim requirements. The
 reports specified in the permit are very
 important and should be submitted on time.
 Failure to report,  especially on construc-
 tion progress or compliance,  will result in
 response from the Agency.

        MONITORING AND  REPORTING

      The self-monitoring requirements  con-
 tained  in the permit will  be  developed on an
 individual basis with consideration  given for
 the  type of treatment,  the impact of the pro-
 posed treatment  facility on the  receiving
 water and the parameter to be measured.   The
 purpose  of the monitoring  program is to
 establish that a treatment facility  is  con-
 sistently meeting the  effluent limitations
 imposed  in the permit.   Data  must be recorded
 and  retained  on  file by the permittee  for at
 least three years.   The reporting frequency
 of monitoring results will be specified  in
 the  permit.   A uniform  reporting  form has
 been developed and will be provided  to the
 permittee.  The  self-monitoring may  vary
 from State  to  State  as  individual conditions
 are  developed  to  insure compliance with
 State requirements.

     The  permits  are issued for fixed terms.
 The maximum duration of  a  permit  will be
 five years.   The  majority  of  permits have
 been written  for  that period  since it will
 involve commitment to a  long  term abatement
 program.  Permits may be written  for a
 shorter period, however, e.g., the State
may require it or the facility may cease
 operation.

           STATE  CERTIFICATION

     After drafting, a permit  is  forwarded
 to the appropriate States  for  certification.
The State has the right  to  add additional
requirements  in monitoring, compliance, and
additional or more stringent  effluent limit-
ations.   The Agency, upon receipt of certi-
fication requirements, will place these in
the permit.  Any  challenge  to  any State
certification requirements must be through
State administrative procedures.
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STATUS OF THE PROGRAM AS OF JUNE 30, 1975

     EPA and 24 States which were delegated
the authority to issue NPDES permits had,
as of June 30, 1975, issued 20,091 Indus-
trial permits; 16,664 Municipal permits;
1,548 Agricultural permits; and 1,988 Fede-
ral Facility permits making a total of
40,291 permits issued.  Approximately 1600
EPA issued permits have been challenged
through Administrative Processes.  Of these,
400 have been resolved through discussions
between interested parties, e.g., govern-
ment, industry, and public interest groups.
We expect very few appeals to proceed
through this process and into our courts.

     A study to determine the total amount
of certain pollutants that will be removed
from our Nation's waters due to the imple-
mentation of P.L. 92-500 and the industrial
portion of the permit program resulted in
an estimated reduction of approximately 12
million pounds per day of BOD and 28 million
pounds per day of suspended solids.

     The continuation of our effort will
now shift into compliance monitoring to
assure that the terms and conditions of the
permits are met and the goals of the Act
achieved.
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                  THE EPA PRETREAlMENT PROGRAM FOR INDUSTRIAL WASTES
                                      Ernst p.  Hall
                                        U.S.E.P.A.
                   401  M Street,  S.W.,(WH5b2)  Washington,  DC
                                                              20460
                                        ABSTRACT
    The Federal  Water Pollution Control  Act Amendments  of 1972 (PL 92-500) directs the
promulgation of  Federal  standards  for  pretreatment of industrial  waste waters which are
introaucted into a publicly owned  treatment works.  These standards will  require pretreat-
ment to control  pollutants which would interfere  with a pass  through a treatment works.
Enforcement will be primarily at the  local  level  with a Federal  overview and presence.
    Pretreatment  of   industrial   wastes
betore   introduction   into  a   publicaly
treatment works (POTW)  has  been   discussed
by  Mr.  Sutfin  at  the second  U.S./Japan
Conference.   Since that presentation  there
have been a  number of refinements   in  our
thinking  and  approach  to  pretreatment.
This paper reflects the present  status   of
these refinements.
    The  Federal  Water  Pollution Control
Act Amendments of 1972, were  designed   by
Congress to  achieve an  important objective
-  to  "restore and maintain the chemical,
physical, and biological integrity of  the
Nation's  waters."  Primary  emphasis  for
attainment of this  goal  is  placed   upon
technology  based  regulations.    Existing
industrial point sources  which   discharge
into   navigable   waters   must   achieve
limitations   based  on   Best   Practicable
Control   Technology  Currently   Available
(BPT) by July 1, 1977 and  Best   Available
Technology  Economically  Achievable  (BAT)
by  July  1,  1983  in    accordance   with
sections  301(b)  and 304(b).  New sources
must comply  with  New  Source  Performance
Standards  (NSP)  based  on Best Available
Demonstrated  Control   Technology   (BDT)
under   section   306.     Publicly   owned
treatment   works   (POTW)     must    meet
"secondary  treatment"   by  1977  and best
practicable  waste treatment technology   by
1983  in  accordance with sections 301(b),
304(dJ and 201 (g)(2)(A).  Users of a POTW
                                               also  fall  within  the statutory  scheme  as
                                               set  out  in  section 301(b).   Such sources
                                               must  comply  with  pretreatment  standards
                                               promulgated pursuant to section 307.
                                                  Limitations   and  standards applicable
                                               to  Direct  dischargers are established  for
                                               categories   and   subcategories  of  point
                                               sources.    This   same  categorization   is
                                               applied  to  pretreatment and pretreatment
                                               standards, generaly, will
                                               for   each   category  or
                                               industrial point  source
                                               general     pretreatment
                                               existing sources  (40 CFR
  be  established
  subcategory  of
  discharge.     A
 regulation   for
128) was  adopted
                                               some  two  years ago and is now undergoing
                                               revision. I he revised regulation  (40  CFR
                                               4u3)  is  expected to provide a regulatory
                                               basis for both existing and new sources.
                                                   The  term  "pretreatment"  means   the
                                               application   of  physical,  chemical  and
                                               biological  processes to reduce the  amount
                                               of  pollutants  in  or alter the nature of
                                               the pollutant properties in a waste  water
                                               prior to discharging such waste water into
                                               a  publicly  owned  treatment  works.   I he
                                               basic  purpose  of  pretreatment  is    "to
                                               prevent  the  discharge  of  any pollutant
                                               through   treatment   works...which    are
                                               publicly owned, which pollutant interferes
                                               with,  passes  through,  or  otherwise  is
                                               incompatible with such works." The  intent
                                               is  to  require  treatment at the point of
                                               discharge complementary to  the  treatment
                                               performed  by  the  POTW.   Duplication of
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treatment  is  not the goal.  Pretreatment
of pollutants which are not susceptible to
treatment in a POTW is absolutely critical
to the attainment of the overall objective
of the Act, both by  protecting  the  POTW
from  process upset or other interference,
and by preventing discharge of  pollutants
which  would  pass through or otherwise be
incompatible with such works.
    Pretreatment  standards  should  allow
the  maximum utilization of a POTW for the
treatment of industrial  pollutants  while
preventing  the  misuse of such works as a
pass-through device.  The  standards  also
should  protect  the  aquatic  environment
from discharges of inadequately treated or
otherwise undesirable materials.
    The  primary  technical  strategy  for
establishing     pretreatment    standards
consists of the  following  provisos:  (1)
pretreatment    standards   should   allow
materials to be  discharged  into  a  POlW
when  such  materials  are similar, in all
material  respects,  to  municipal  sewage
which  a "normal type" POTW is designed to
treat; (2) pretreatment  standards  should
prevent the discharge of materials of such
nature   and   quantity,   including  slug
discharges, that they  would  mechanically
or   hydraulically   impede   the   proper
functioning of a  POlW;  (3)  pretreatment
standards  should  limit  the discharge of
materials   which,   when   released    in
substantial   concentrations  or  amounts,
reduce the biological effectiveness of the
POTW or achievement  ot  the  POTW  design
performance,  but  which  are treated wnen
released in small or  manageable  amounts;
and   (4)  pretreatment  standards  should
require  the  removal,   to   the   limits
dictated by technology, of other materials
which  would  pass through — untreated or
inadequately treated --  or  otherwise  be
incompatible with a normal type POTW.
    In  addition  to  these  provisos,  it
appears to be  administratively  necessary
and  technically  desirable to establish a
volume cutoff or limit  below  which  most
materials  may  be discharged into a POTW,
while requiring pretreatment standards for
larger flows and more hazardous materials.
This is intended  to  be  accomplished  by
defining,   for   the   purpose   of   the
regulation, a major contributing  industry
is  a discharger who either (a) has a flow
of 50,000 gallons per day, or  (b)  has  a
flow  equal  to  or greater than 5% of the
capacity  of  the  POlW.   Any  discharger
meeting either of these requirements would
be  subject  to all pretreatment standards
while a discharger  not  classified  as  a
major   contributing   industry   by  this
criteria  may  not  be  required  to  meet
specific numerical pretreatment standards.
The  specific  determination is to be made
in each subpart and  for  some  particular
subparts  it  may be desirable to alter or
change the definition of a  major  contri-
buting  industry in order more properly to
apply pretreatment standards, particularly
where use of the volume cut-off would  not
provide   adequate   protection   to   the
environment.
    The first  proviso  is  clear  in  its
application  and  materials  meeting  this
proviso should be allowed to be introduced
into a POTW without  pretreatment.   uther
applications  ot  these  provisos  will oe
discussed in the following paragraphs.
    ihe control of influent pH is  usually
adjusted   adequately,   particularly  for
mildly acid wastes, by the alkalinity  and
buffering  capacity  of  normal  municipal
waste waters.  Additionally, if necessary,
treatment   of   pH   can    readily    be
accomplished  by  chemical  addition  in a
POTW.    However,   highly   acid   wastes
characterized  by  materials  having  a pH
below  five  have   the   capability   for
destroying  the  sewer  pipes  and  sewage
treatment facility itself because of their
ability  to  attack  metal,  concrete  and
mortar  joints.   One particularly adverse
reaction from the corrosion of acid wastes
is to destroy the integrety of in concrete
sewers, thereby allowing the  infiltration
of  water during a rainy season.  For this
reason, very low pH wastes -- below  a  pH
of  5.0  --  are  included  as  prohibited
wastes  even  though   pH   is   generally
considered  to  be adequately treated in a
POTW.
    Heat  is  defined  in  the  Act  as  a
pollutant.   In most cases, heat in fairly
substantial quantities can  be  discharged
into  a municipal sewage system along with
waste water without causing  an  upset  or
other  difficulty  in  operating the POTW.
As  a   matter   of   fact,   some   heat,
particularly in cold weather, may prove to
be  beneficial,  and  may  accelerate  the
effectiveness of  the  treatment  process.
However,    the   normal   POTW   includes
biological   treatment    systems    whose
performance  can  be affected adversely if
an  excess  of  heat  is  found   in   tne
treatment  plant  itself.   This  point of
damage to biological activity is generally
                                           639

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 considered to  be  40%C  (|04%F).    Hence,
some  safeguard  is  needed  to prevent an
excess of heat  being  discharged  to  the
treatment   plant   while  still   allowing
lesser amounts of heat to be discharged to
and dissipated in a POTW.
     Slug discharges which cause  an  upset
in  the treatment process and a subsequent
loss  of   treatment   effectiveness   are
undesirable  both  for  environmental  and
treatment   plant   operational   reasons.
Defining  a  slug  discharge in quantative
terms  is  difficult.   It   is   commonly
recognized  that  the  peak  two hour flow
rate of normal municipal sewage  is  about
two  times  the ratio of the average daily
flow.  This ratio holds for both hydraulic
loading  and  for  oxygen   demand   (BOD)
loading.   In order to establish a readily
definable  discharge  level  at  which  an
industrial  user  may  become  liable  for
causing a POTW upset, a slug discharge  is
defined  based  on  the  normal maximum to
average ratio.   However,  the  prohibited
waste   section  does  not  prohibit  slug
discharges per se but only prohibits  slug
discharges which cause a POTW upset.
     Some materials are known to be treated
effectively  in  small concentrations in a
POTW  but  are  not  treated   effectively
whenever  the  amount  of  such  materials
exceeds  the  system's  tolerance   levels.
Regulation of these types of materials can
effectively  allow  the  POTW  to treat as
much of the  pollutant  as  it  reasonably
can,  while  preventing  an excess of such
material from passing through untreated or
reducing the  treatment  effectiveness  of
the  PuTW.   One  such  material currently
under review by  the  Agency  is  oi I  and
grease of a mineral origin.  The Agency is
considering    establishing    a   general
limitation  setting   forth   a   specific
concentration  as  a pretreatment standard
for  this  particular  parameter   and   a
request   for   public   comment  on  this
proposal has been published in the Federal
Register   (40FR17/62).    This    general
limitation  would  be  implemented in each
subpart  regulation  rather  than    in   a
general  regulation.  Other materials such
as  ammonia,  phenol  and  cyanide  may  be
considered  for   limitation  in  the  same
manner as oil  and  grease  of  a  mineral
origin.
     Materials  may  at  times be introduced
into a POTW in industrial waste waters for
which no  treatment effectiveness data  tor
a   normal  type   POTW are available  or for
wnich  the  known   data   indicate   that
treatment  effectiveness  in  the  POTW is
highly variable or  inadequate.   In  such
cases,  it is obvious that the POTW cannot
be  depended  upon  to   effectively   and
consistently   remove   the  pollutant  in
question.   Under  these  conditions   the
Agency expects to consider the application
of   BPT   or   NSP   limitations  as  the
pretreatment standard for  these  specific
materials.    Materials   which   may   be
included in this  category  would  include
metals  such  as copper, nickel, chromium,
zinc and  arsenic,  and  selected  organic
materials.
    Regulations under sections 301 and 306
generally  have  been established allowing
the discharge of a  quantity  or  mass  of
pollutant  related to a unit of production
or other production  vector.   This  basis
tor   limitation   has   the  considerable
advantage of reducing the discharge of the
amount of pollutants to a finite  quantity
while  encourging  conservation in the use
of  water  and  the   reduction   in   the
generation   of   waste   water  within  a
manufacturing process or  operation.   ihe
Agency believes that mass limitations Dest
fulfill  the  purposes  of  the Act.  Mass
limitations     based      on      similar
considerations appear to be the most sound
and  effective  mechanism for reducing the
amount of pollutants discharged to a  POTW
whenever   such   pollutants   would  pass
through or otherwise be incompatible  with
such  works.    I he  Agency  intends to use
this  concept  of  limiting  the  mass  of
pollutants  discharged  as  the  technical
basis    tor    the    establishment    of
pretreatment     standards     for    many
pollutants.
    The enforcement  strategy,  which  the
Agency   proposes  to  employ  to  achieve
pretreatment    of    industrial    wastes
envisions  tne application and enforcement
of these pretreatment standards  by  State
and   local   bodies  including  the  POlW
receiving  and  treating  the   industrial
waste waters.   It has been determined that
many  State  and local authorities are not
yet able to apply production related  mass
limitations.   Moreover,  the Act does not
provide for pretreatment permits analogous
to the NPDES permits of section 402.   For
this  reason,   the  Agency,  at this  time,
expects    to    promulgate     pretreatment
standards  which are based on the  discharge
of    a   specified  quantity  of   pollutant
related  to a production vector  (e.g.,   Ibs
                                            640

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of  pollutant  per  ton  of  product), but
which are stated  as  a  concentration  of
pollutant   in   the   discharge   from  a
particular  industrial  process  or   unit
operation.   It  is  anticipated  that the
rationale  for  the  derivative   of   the
pollutant  concentration standards will be
described in detail  in  the  preamble  to
each    pretreatment   standard   for   an
industrial  subcategory.    It   is   also
anticipated    that    restrictions    and
constraints against water use and dilution
may be included when appropriate for  each
subpart.    It   is   intended  that  such
pretreatment standards be applied  at  the
individual  process unit.  Additionally an
alternate   procedure   will    be    made
available,  as  is  appropriate  for  each
subpart, so that mass  limitation  may  be
applied  if  both  the industrial user and
POTW operator desire.
    The Agency believes that  the  use  of
pollutant concentrations as a pretreatment
standard  for  those  materials  which may
pass through untreated, or  are  otherwise
incompatible  with  a  POTW  is an interim
measure made necessary  by  the  practical
constraints   of   enforcement.   At  some
future  revision  of  these   pretreatment
standards, the Agency anticipates that the
concentration  numbers  will  be abandoned
and the mass limitation  will  become  the
sole pretreatment standard.
    All   of  the  pretreatment  standards
being considered are intended to apply  to
users of a "normal type" of publicly owned
treatment   works   which   is   basically
designed and intended  to  treat  domestic
waste  waters  to  achieve  the  secondary
treatment standards as established  in  40
CFR  133  and as required by the Act.  The
secondary treatment standard requires that
a sewage treatment plant, in  addition  to
controlling  pH and fecal coliform, reduce
the amount of  biochemical  oxygen  demand
(BOD5)  to  85  percent  or  less  of  the
influent  value  or  to  30  mg/1  in  the
discharge,    whichever    is   the   more
stringent.   A  similar   restriction   is
applied to suspended solids.
    There are a number of sewage treatment
systems,  which when properly designed and
operated, meet  these  requirements  on  a
consistent   basis.    These  include  the
activated   sludge    system    and    its
modifications,    trickling  filters,  and
stabilization  lagoons or oxidation  ponds.
There  are  a  number  of activated sludge
system  modifications  which   incorporate
variations   on   the   amount  of  sludge
recirculation, the amount of air or oxygen
supplied to the reaction chambers, the use
of pre- and post-chlorination, and the use
of sludge digestion, sludge combustion, or
land filling as mechanisms tor disposal of
the sludge generated.  The retention  time
of  sewage  in  such  systems generally is
short; it is nominally considered to be  6
hours  while retention times as short as 3
or 4 hours are  not  uncommon.   Trickling
filters  are  often  used  where the input
waste water  is  relatively  constant  and
where   savings   in  power  and  operator
attention   are   needed.    Stabilization
lagoons  or  oxidation  ponds  can be used
where the necessary land area is available
and where climatic and soil conditions are
such  that  the   long   retention   times
required  by  such lagoons or ponds can be
achieved.  "A normal type" POTW should not
have   regular,    substantial    chemical
additive needs for the purpose of removing
materials other than BOD and TSS.
    Existing   publicly   owned  treatment
works rarely  include  processes  such  as
physical chemical treatment (which is only
now becoming a full scale reality in a few
areas) or special variants or combinations
of  biological  treatment  units  that are
primarily intended to address the  special
needs of industrial waste water pollutants
rather   than   domestic  waste  or  water
quality requirements.
    Variations   from   the    promulgated
pretreatment standards may be necessary in
certain  circumstances  to  compensate for
factors  not  adequately   considered   in
establishing  these  standards.   This has
been recognized in  the  establishment  of
other  industrial effluent limitations and
is  equally  applicable  to   pretreatment
standards.   Two  kinds of variants appear
to  be  appropriate   depending   on   the
particular circumstance.
    In  the preparation of the development
document for each  point  source  category
all  of  the  information which the Agency
could  collect  concermnq  processes  and
procedures   related   to   the   industry
subcategory was  collected  and  analyzed.
It  is  possible,  however,  that  certain
facts did  not  become  available  to  the
Agency   and  could  not  be  employed  in
decisions related to the pollutants  which
may   be   discharged  from  a  particular
industry operation or would be related  to
the  treatability  or  impact  which   such
pollutants might have upon  a  POTW.   For
                                           641

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this reason, a variance clause is provided
which  would  allow the establishment of a
pretreatment  standard,  other  than  that
promulgated  in the applicable subpart, in
those cases where it could be  shown  that
factors  related  to the industry category
fundamentally   different    from    those
considered  in  the  development  document
exist and that these factors  require  the
establishment  of a different pretreatment
standard.
    An analogous situation may occur  with
respect to factors related to the publicly
owned  treatment works.  A variance clause
is   provided   to   allow   a   different
pretreatment  standard  to  be established
for those cases  where  a  publicly  owned
treatment   works   can  be  shown  to  be
substantially different  from  the  normal
type  of publicly owned treatment works on
which  pretreatment  standards  are  being
based.     Some    of   these   types   of
installations are known to exist or are in
the planning or design stage.  However, at
this time it is difficult to  establish  a
separate  regulation  which  would make an
allowance for different  factors  in  such
publicly owned treatment works.
    Although  both EPA and the States will
play major roles in enforcing pretreatment
requirements,  the  Agency  believes  that
local  governments  will  probably have to
play  the  most  important  role  in   any
successful   enforcement  program.   Local
governments operate the POTWs, which are a
vital part of the overall effort to  clean
up  the  nation's  waterways,  and  so are
sensitive to and directly affected by  the
pretreatment program.  They are closest to
the  problem  and  are  already frequently
involved  in   related   areas   such   as
regulation  of  sewers  and  collection of
user charges.  Moreover, a local  role  in
pretreatment   enforcement  is  consistent
with the partnership of Federal and  local
effort  found  in  the construction grants
program and other parts of the Act.
    As those with the most immediate stake
in  the  success   of   the   pretreatment
program,  both  in  terms of protection of
the proper functioning of the POTW and  in
terms   of   protection   of   the   local
environment, local governments will be the
first line of defense.  One way  they  may
exercise tneir crucial role is by means of
a local  ordinance - a preferred route, and
one specifically preserved by the Act.  It
is   expected   that  each  manager  of  a
treatment works  would  provide  for  such
standards." Local governments may also use
the  citizen  suit  provisions  of section
505.  Section  505  is  available  because
local governments are "persons" as defined
in the Act "having an interest which is or
may  be  adversely affected".  The citizen
suit provisions allow suit  to  enforce  a
Federal  or  State  pretreatment  standard
either against the industrial user of  the
POiW  or  against  the  State  or  Federal
government (for  failure  to  take  proper
action).    The  Agency  anticipates  that
pretreatment guidance  published  pursuant
to section 304(fj will be of assistance to
local  governments  in  carrying out their
responsiblities.
    The  Agency  believes  that   parallel
efforts  of all three levels of government
will   be   needed   for   a    successful
pretreatment   program.   To  the  maximum
extent possible, EPA  will  encourage  and
assist State and local enforcement action.
                                           642

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                   MUNICIPAL SEWER UTILITY FINANCING UNDER PL 92-500*

                              C. C. Taylor, Program Analyst
                             Environmental Protection Agency
                              1421 Peachtree Street, N. E.
                                 Atlanta, Georgia 30309
                                        ABSTRACT

     The Water Pollution Control Act Amendments of 1972 imposed significant financial
requirements upon grantees under the Federal Construction Grants Program administered by
the Environmental Protection Agency.  This paper discusses the legislative history and
implementation experience of these grant conditions which are commonly referred to as the
user charge and industrial cost recovery requirements.

     All recipients of Federal construction grants must demonstrate legal., financial, and
managerial capability to complete construction and provide adequate operation and main-
tenance during the life of the facility.  Grantees must also develop and implement user
charge systems whereby all users pay the costs of operation, maintenance and replacement
in proportion to their use of the treatment facility.  Such charge systems must also in-
clude provisions for reimbursement of Federal construction costs allocable to industrial
users.

     The Environmental Protection Agency's implementation of these statutory requirements
is impacting the institutional pattern of municipal sewer utility management.  More
adequate operation and maintenance is assured, and greater equitability in the distribu-
tion of costs is being attained.

     Public response to the imposition of user charges has been reasonably receptive.
Compliance with industrial cost recovery requirements continues to generate controversy,
particularly with respect to applicability, cost allocation, and accountability.
              INTRODUCTION

     During the long and somewhat torturous
legislative history of The Water Pollution
Control Act Amendments of 1972, the Honor-
able Robert E. Jones of the U. S. House of
Representatives characterized this legis-
lation for his collegues as follows:  "Mr.
Chairman, this is an enormously complex
bill, and necessarily so, because our water
environment has become enormously compli-
cated because of the urbanization and in-
dustrialization of our society.  Our legis-
lation must take into account the myriad
of the water needs issue" (1).**

     Subsequent to enactment, the act has
been called many things, ranging from the
most significant legislation of the decade
to the most comprehensive, the most com-
plex and the most confusing legislation
ever enacted at any time or place in the
history of man.  Whether or not either of
these latter characterizations are justi-
fied, PL 92-500 is, without doubt, compre-
hensive in scope.  Many of its provisions
are complex, and implementation of some of
 *Paper prepared for presentation at Fourth
  U. S,/Japan Conference on Sewage Treat-
  ment Technology, Washington, D. C.,
  October 28-29,1975.
**Numbers in parentheses designate refer-
  ences on page 6.
                                           643

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the provisions have been accompanied by some
confusion and controversy.   This includes
implementation of significant provisions
relating to cost-sharing and cost alloca-
tion.  The emphasis of this paper is fo-
cused upon these financial aspects of the
subject legislation.

         BACKGROUND OF PL 92-500

     In the spring of 1967, a joint Commit-
tee of the American Public Works Associa-
tion, the American Society of Civil
Engineers, and the Water Pollution Control
Federation reviewed the most significant
problems of the broad area of administra-
tive, legislative, and financial issues of
municipal water and sewer service.  As a
result of the initial review, the Commit-
tee decided to focus its activities upon
the most urgent area, namely wastewater
financing and charges  (2).  This was indic-
ative of the general conclusion that most
of our municipalities were not adequately
prepared, at that time, to assume and
manage the rapidly escalating financial
and  administrative responsibilities of
sewer service.

     A leading management consultant firm,
working under contract with EPA Region
VIII, found this general situation little
changed by 1972  (3).  Our nation is, of
course, geographically large and widely
diverse with respect to political structur-
ing.  Obviously, this broad generalization
did  not apply to all municipalities indivi-
dually.  However, as a general rule, munic-
ipal sewer utilities were operated largely
as a public service financed by annual
appropriations from general revenues.
Generally, cost  accounting systems, and
their attendant  legal  and financial insti-
tutions were not adequate for efficient
operation  as  financially self-sustaining
public utilities.  It was in this atmos-
phere that The Congress deliberated legis-
lation which  culminated in PL 92-500.

     During  this legislative process, many
complex and  controversial  issues were dis-
cussed and debated, after which  some were
resolved  and  some  apparently compromised.
These deliberations are reflected in the
'Committee  and conference report  (1).

     Of  the  significant issues  debated,  two
pertain  directly to our subject  of  finan-
cial management.   First,  Congress  fully
recognized that  the  costs  of attaining
the desired levels of clean water were
going to be large - we might even say
enormous.

     The most recent "Needs Survey" cost
estimate for the backlog of municipal
facilities which are normally funded under
the EPA Construction Grant Program - that
is, only treatment facilities and attendant
interceptors and outfalls - was at the
level of approximately 50 billions of
dollars (4).  We have known for some time
that attainment of the desired levels of
pollution control was going to be costly,
and Congress was fully aware of this as
they legislated this act.

     Second, the committee reports reflect
that Congress also was fully aware of the
basic necessity of getting maximum return
for each dollar of this enormous investment
and that this could be done only with im-
proved and adequate operation and mainte-
nance.  Why go to the expense of building
these facilities if they were not going to
be operated and maintained in such a way
that they would do the job for which they
were designed?

     As a result of these deliberations,
the Congress reached some basic decisions.
First, the level of Federal cost sharing
for the construction costs of the large
backlog of needed publicly-owned municipal
facilities would be raised to 75 percent.

     Second, it would be necessary to find
some way to move our municipal sewer sys-
tems to a sounder financial basis whereby
they could become more financially self-
sufficient.  This should be done by pro-
moting a shift of the sewer service
function from a public service basis to a
public utility basis whereby;

     a.  Wastewater treatment and control
         service would be paid for by the
         users of that service.

     b.  The users would pay these costs on
         the basis of the extent of their
         use of the system.  In this way,
         there would be an economic and
         financial incentive to reduce
         waste discharge or at least hold
         it to an amount for which each
         user would be willing to pay.

     Third, after extended, and apparently
heated debate about the Federal funding of'
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9.   PROPOSED  SEWERAGE SERVICE AREA  OF  EACH  MUNICIPALITIES
     FOR RESPECTIVE PHASES
(1)  Priority and its concept
     The priority for sewage works of each municipalities is determined by taking
into account the following:
     a)   Magnitude of effects on water quality
     The order of the magnitudes of cost-benefit ratio (volume of removal of
pollutant loads per unit cost) of the sewage works required to remove loads for the
purpose of attaining the environmental standards at each stations in 1975.
     b)   Magnitude of necessity of improvement of the environment
     The order of population densities (as census of 1970) reckoned as overcrowded
index showing the urban environmental aggravation.
     Based on  the above  two factors  the conditions of sewage works under ways,
conservation of water sources, aggravation of environment and other various factors
are put together to determine the priority of sewage works as follows.
         i)   Areas to launch immediately into the sewage works
     Hiroshima  City (local  sewage works, Ohta River  Service Area,  Seno River
Service Area), Koyo Town, Hiroshima City (Gion), Yasufuruichi Town.
         ii)  Areas to launch as early as possible
     Itsukaichi Town, Hiroshima City  (Kabe), Sato  Town, Fuchu Town, Funakoshi
Town, Kaita Town, Senogawa Town, Yano Town.
         iii)  Areas to launch early
     Aki Town, Hiroshima City (Numata), Saka Town.
(2)  Proposed sewerage service areas for respective phases
     The service  area  by the sewerage required  for  purpose of attaining  the
environmental water quality standards for 1975  and 1980 is shown in Table 19.
     And for 1985  and 1990, sewerage  service  area will  be  covered  to achieve
pollutant load reductions  more than specified in the guidelines for the purpose of
improving amenity.
                  Table 19  Area of Coverage for the Planned Years
Year
1975
1980
1985
1990
1990 service area
(ha)
16,596 (ha )
Service area by year
(ha)
4,256
7,931
13,665
16,596
Ratio of service area
(%)
26
48
82
100
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10.  EFFECTS OF THE  PROGRAM ON WATER QUALITY PROTECTION
     It  is insufficient that the  protection  of the quality of public waterways
presupposes at once consideration to the utilization of waters by men. We should
take account into the conservation of minimum environmental standards necessary
for fellow living creatures.
     As regards the Ohta and Seno River Basin, the water quality should be restored
to a point  of allowing swimming  as Hiroshima was  once called as "the City of
Waters".
     Based on this principle, the program will be evaluated not only to improve the
environment, consequently to prevent water pollution, to regain clean waters, and to
conserve water sources, but also to improve the water  quality to the level shown in
Table 20 which  will be  high  enough  even if the environmental water quality
standards are tightened in the future.

             Table 20 Water Qualities at Each Stations for Respective Phases
_^^^ Water qualities
Standard stations ^~~""— - — _^_^
Ohta River,
1. Intake point of Hesaka
water supply
2 Ohta canal,
' Asahi Bridge
o Temma River,
' Showa Great Bridge
4 Original Ohta River,
Funairi Bridge
j Motoyasu River,
Minami Great Bridge
g Kyobashi River,
Miyuki Bridge
7 Enko River,
Niho Bridge
o Seno River,
Hinoura Bridge
Existing water
quality
(BOD ppm)
1.6
(A)
4.5
(B)
1.3
(A)
1.2
(A)
0.6
(A)
1.7
(A)
10.1
(C)
3.2
(B)
Classification
Left alone
Improved by
implementation
Left alone
Improved by
implementation
Left alone
Improved by
implementation
Left alone
Improved by
implementation
Left alone
Improved by
implementation
Left alone
Improved by
implem entation
Left alone
Improved by
implemen tation
Left alone
Improved by
implementation
Predicted water quality (BOD ppm)
1975
2.9
2.0
5.7
3.0
1.7
1.7<
1.5
1.5<
0.6
0.6<
1.7
1.7<
12.0
8.0
4.9
4.9<
1980
4.4
2.0
7.3
3.0
2.1
2.0
1.9
1.9<
0.6
0.6<
1.7
1.7<
14.8
5.0
8.2
3.0
1985
6.0
0.6
9.0
0.6
2.7
0.6
2.4
0.6
0.8
0.8
1.8
1.6
18.2
0.6
10.3
0.8
1990
7.6
0.6
10.9
0.6
3.3
0.6
2.9
0.6
0.8
0.8
1.9
1.7
21.7
0.6
13.0
0.9
Note:  Letters parenthesized denote types of waterways according to environmental water quality standards.
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11.  FUTURE STUDIES
     In the preparation of the program, some assumptions are made for want of data
concerning water pollution.
     From now on, various data, especially those concerning water qualities should
be collected in order to provide for every-five-year previous  and the following
studies should be  pushed  forward to refine the plans  for promoting  the sewage
works reasonably.
(1)  Improvement of the existing combined sewer system
     The effects of wet weather conditions on the water quality of the combined
sewer system should  be studies in order to provide measures for sewage treatment
and modification into separate  sewer system and to determine their implementation
schedule.
(2)  Development of  water pollution mechanisms in the tidal waterways
     The tidal waterways in  the lower reaches of the Ohta River (Hiroshima City)
are experiencing some 3 m of tidal range.  As pollutant loads running into the tidal
waterways have different effects on water qualities depending on the tidal current
and the  change of water level, the pollution mechanisms should  be developed along
with analysis  of  measurements  at stations with reference  to  the water quality
standards.
(3)  Examination of pollution in sea
     Water quality  conservation in the Bay of Hiroshima should also be studied with
reference to the environmental water quality standards.

12.  IMPLEMENTATION OF  SEWAGE  WORKS
     According to  the studies, the Ohta River comprehensive  sewage works was
launched in 1972 and a part of the alignment of trunk was completed in 1974.
     From this year on, the construction of sewage  treatment plant will be started.
     Along with the Program, Hiroshima City local sewage works is also in progress.
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                               Fourth US/JAPAN Conference
                                        on
                                Sewage Treatment Technology
                                     Paper No. 6
FURTHER  DISCUSSIONS OF THE  FEDERAL  WATER
       POLLUTION  CONTROL  ACT  OF  1972
                   October 29, 1975
                   Washington, D. C.
                Ministry of Construction
                  Japanese Government

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FUTURE DISCUSSIONS ON FEDERAL WATER POLLUTION CONTROL ACT
AMENDMENTS OF 1972
  T. Kubo, Japan Sewage Works Agency

1.   INTRODUCTION	>	378
2.   THE GOALS AND POLICY OF THE ACT	378
3.   MUNICIPAL SECONDARY  TREATMENT	379
4.   FINANCING	381
5.   OCEAN OUTFALLS AND OCEAN DUMPING	381
    5.1  Ocean Outfalls	381
    5.2  Ocean Dumping	382
6.   PRETREATMENT	384
7.   USER CHARGE	386
8.   INDUSTRIAL COST RECOVERY	391
                             577

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1.   INTRODUCTION
     At  the  Second  U.S./Japan  Conference  on Sewage Treatment Technology,
December 1 ~ 6, 1972, in Washington, D.C., presentation in relation  to the Federal
Water  Pollution Control Act amendment of 1972 was made  by U.S. side to the
Japanese Delegation, when it was just beginning to implement the Act. During the
Second Conference the Japanese  Delegates recognized that the great amount of
discussions had  been made  in  the House  and  Senate  on the Act  itself and the
national  policy for environmental pollution, and the passage of the Act was really a
historical event in the field of water pollution control in the United States. And the
Japanese Delegates then paid attention on its thoroughness and comprehensiveness,
and  paid respects  to the nation's ambitious goals which  were  set against water
pollution control.
     At  the Third  Conference,  February 12 ~ 16, 1974, in Tokyo, Mr. Charles H.
Sutfin  of U.S. EPA Headquarters, Washington, D.C., described that since 1972 U.S.
EPA had worked very hard, learned much and in doing so significant progress had
been  made  toward  full implementation  of the Act.  As we can  see  it in the
Proceedings  of  the Third  Conference that the state viewpoint and municipal
viewpoint presented during the Third Conference made it clear that the various state
governments  and local municipalities had no single viewpoint on  the merits of the
1972 Act. During the Third  Conference various arguments and criticizms on the Act
were raised by both the U.S. and  Japanese side and also made some comments on it
particularly from viewpoint  of water quality standard, effluent standard, grants for
construction  of treatment works,  research and  related programs. It seems that most
of state  civil servants think  that the Act has produced serious  flaws in the field of
water pollution  control and has been wrongly  implemented, for instance, Section
101 (b) of the Act states that it is the policy of the Congress to recognize, preserve
and protect the primary responsibilities and rights of States to prevent, but actually
the federal role  is  all pervasive and conformity  to the  federal mold  is much more
mandatory  than statutory   language  would  require,   and  the  goals  indicating
recreational use water quality in all streams by 1983 and zero discharge of pollutants
by 1985 are  unrealistic, particularly the  schedules. We  realize that  there must be
difficult  problems  for full implementation  of  the Act, and nevertheless we would
like  to pay our respects to EPA's ambitious  goals in  the field of environmental
pollution control through full implementation of the Act. Today, I  would like to
discuss with you on several  points of the Act,  but particularly  to emphasize the
specific area of pretreatment, user charge system and industrial cost recovery under
the Act.

2.   THE GOALS AND POLICY OF THE ACT
     The goals and policy of the Act are declared in the Section 101 (a) of the Act,
to wit;
(1)  It is the national goal that  the discharge of pollutants into the navigable waters
     be eliminated by 1985.
(2)  It is the national goal  that  wherever  attainable,  an interium  goal of water
     quality which provides  for the protection and propagation of fish, shellfish and
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     wildlife and provides for recreation in and on the water be achieved by July 1,
     1983.
 (3)  It is the national policy that the discharge of toxic pollutants in toxic amounts
     be prohibited.
 (4)  It is  the  national  policy  that  Federal financial assistance be provided  to
     construct publicly owned waste treatment works.
 (5)  It is the national policy that areawide waste treatment management planning
     processes be developed and implemented to  assure adequate control of sources
     of pollutants in each State.
 (6)  It is the national policy that a major  research and demonstration effort be
     made to develop technology necessary to eliminate the discharge of pollutants
     into the navigable waters, waters of contiguous zone, and the oceans.
     It can  be deeply recognized for us that the public in the U.S.A. has become
 more aware  of water pollution  and the climate  of public opinion has remarkably
 changed  to  support the clean-up  effort in the activities  of Federal, State and
 municipal levels. -Of course, without the public's support, it will be impossible to do
 the job of water pollution control.  The passage of the 1972 Act is very significant
 that the  goals are indicated clearly for the nation's commitment to clear water and
 the Act is certainly a commendable effort on  the part of the Federal Government to
 upgrade  and/or preserve the chemical, physical and biological integrity of the
 nation's  waters,  and  the  public  is   encouraged by the  Federal  Government's
 recognition  of the  problems of water pollution and  its determination to deal with
 these problems.
     It is understandable  in  general  that the  concept  of setting  water quality
 standards for the nation's waters and the concept of specifying minimum treatment
 levels  regardless of stream requirements are  sound and agreeable. The  continuing
 planning process mandated by  Section  303  (e)  of the Act  is a also  sound and
 necessary to  take comprehensive countermeasure for pollution prevention. This kind
 of planning  can lead to take a more effective  view at  the overall water quality needs
 in each river basin and also  lead to keep a much more coordinated control program
 than has been the case. It seems that  State Governments and  municipalities would
 express their attitude to  keep close  coordination  with  federal government to
 implement the 1972 Act.
     Under these circumstances it seems that  the goals and policy of the Act should
 not be altered and all governments in  each level and  the public would try to attain
 the goals, even if there must be some change in the schedules to  attain  the goals.

 3.   MUNICIPAL  SECONDARY TREATMENT
     Section  301  (b) (1) (c) of the Act says in effect that by July 1,  1977 publicly
 owned treatment works shall produce either a secondary treated effluent, or an
 effluent subject  to  advanced  waste  treatment if this is required  to meet stream
standards. It seems to me  that the requirement  that all municipalities provided a
minimum of secondary  treatment  by  1977  may be  difficult in some instances
because of the time needed to plan, design, and construct facilities and also shortage
                                       379  -

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of budgetary action.
     According to the Secondary Treatment Information on secondary treatment
pursuant to Section 304 (d) (1) of the Act, secondary treatment may not be capable
of meeting the percentage removal requirements during  wet weather in treatment
works which receive flows from combined sewers. For such works decision should
be made on case by case basis as to whether  any attainable percentage removal level
should be. In  any case it will need huge amount of fund to meet requirements in
these cases. Section 202  (a) provides that  the amount  of any Federal grant  for
publicly owned waste treatment plant made under the Act shall be 75 per centum of
the  cost of construction. But actually the  level of funding as evidenced by past
experiences would fall far short of the need. On the  contrary national pollutant
discharge elimination system as provided with Section 402 of the Act will require to
apply and insure compliance with Section 301, 302, 306,  307 and 403. Moreover in
the NPDE system discharge from storm overflow on combined sewers to public on
case by case basis.
     When the permit program  is  coupled  with the grant program  for  publicly
owned treatment works as established under Title II of the Act, a real dilemma does
result. Actually it would appear to us that the federal government is telling state and
local municipality on  the one hand  through  permit system to construct rapidly the
needed publicly owned treatment works; and on the other hand telling same state
and  municipality through the  grant program that they are entitled to receive 75%
federal funding, but it will not be forthcoming in many  cases in  time to meet the
1977 deadline. These two hands make confusing.  It is extremely necessary to resolve
this  problem so that federal government can  proceed harmoniously to construct the
necessary  works and  also to maintain and  operate  the  works satisfactorily. The
congress  is always hurry to take action and  determine  the deadline in disregard of
possible  materialization, but  the  engineers  should  consider the attainable  and
reasonable  deadline. What date is it reasonable  to attain the goal of 1977? There
must be many difficulties to cope  with  the time limitation of the Act  for small
communities. Judging from my knowledge I  am  still obliged to acknowledge that it
will  be too  short to attain not only the deadline of  1977 but also the ambitious
national goals. It is easy  to propose ammendments  that will establish reasonable
compliance schedules of the Act. But in the other hand we should pay attention that
frequent ammendments might lose confidence for the national policy in the public.
     We  have   same  problems in  Japan.  In  our Japanese  practice when  the
environmental  quality  standard is fixed  in  some river basins, it will be usual to
determine the  deadline to attain the standard in each  river  basin according to the
classification of environmental quality standard,  and the deadline  itself will not be
so rigid, for instance, it will be indicated  in such a way that 'within five years or as
soon as possible within ten years' either by  industrial waste treatment or publicly
owned treatment plant. But it is still >in many cases impossible to keep the deadline
because of  various  difficulties  such as  shortage of budget available,  lack  of
well-trained  engineers  etc. In  addition to this in most of Japanese large  cities the
combined  sewer system has been taken and in many cases storm-overflows do exist
on sewers.
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     In these cases it needs huge amount of money to meet the requirements which
will be decided on the case by case basis.

4.   FINANCING
     In Japan a significant  problem related to the water program involves acute
future financing of municipal waste treatment works. It seems  to  me that the
situation on this matter in U.S. will be same as in Japan. Expanded eligibilities, more
stringent abatement requirements, and increased construction costs have combined
to raise the demand for federal grants far beyond the levels contemplated when the
1972 Act was enacted.
     EPA's  1973  needs survey conducted  under  Section 516 (b) (2) of the  Act
identified a potential demand of 45  billion dollar from the Federal Government to
fund  project estimated  to cost 60  billion dollar.  A recent needs survey of 1974
shows that the cost of construction of all needed publicly owned treatment works in
all of the States  is  115 billion dollar.  But when  the costs  for treatment and/or
control of storm waters are included, the total  costs will come to 350 billion which
will be a  huge sum of money to take  a budgetary measure.
     It seems that U.S. EPA is looking at  such alternative financing strategies as
differences in funding, in matching formulas, and in eligibility requirement to meet
the deadline. I  would like  to follow such a financing strategies in the U.S. EPA's
policy, because in Japan the Third Five-Year Plan (1971 ~ 1975) for Sewage Works
will be completed by being invested amounting 2,600 billion yen, but it is expected
to have another Fourth Five-Year Plan (1976 ~ 1980) for Sewage Works carried out.
     The Ministry of Construction has made it clear that the total cost estimates for
construction of publicly owned wastewater treatment  plants and collecting sewers
will need another 16,000 billion yen to  attain the environmental quality standard in
each  river basin in Japan. Japanese Environmental Agency is responsible  to fix
environmental quality standard, and has already completed to fix it in about 300
river basins.  We have continued arguments in relation to financing on sewage works
and how to meet with needs and requirements.
     Recently  Ministry of Construction has  requested  to  Ministry of Finance that
the Fourth Five-Year Plan for Sewage Works should be appropriated 11,000 billion
yen for the budget. Even if such program is proceeded completely the target dates
will  be  postponed  for some years, but  Ministry  of Finance has  still showed
unwillingness for such a huge budgetary request.
     Under  these  circumstances we shall have to look  for alternative  financing
strategies to  attain environmental quality standard.

5.   OCEAN OUTFALL AND OCEAN DUMPING
5.1  OCEAN OUTFALL
     The U.S.  EPA published information on secondary  treatment under Section
304  (d) (1)  of  the  1972 Act. It  described  the  minimum level of effluent  quality
attainable by secondary  treatment in terms of the  parameters BOD, SS, PH and B.
Coli.  It requires, in general, 85% removal or 30 mg/C of BOD and SS whichever is
more stringent.  All publicly owned treatment works must provide treatment at least
                                     381 -

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to this level by July 1977. We realize the  1972 Act and its legislative history clearly
shows that the regulation  is principally to be based on the capabilities of secondary
treatment technology and  not ambient water quality effects.
     In  the case  of more stringent  limitation, including those  necessary to meet
water quality standard required to implement any applicable water quality standard
established pursuant to the 1972  Act, it shall be obliged to provide more advanced
waste treatment technology. In the sense of necessity to meet water quality standard
it will be necessary to  take in account of  capabilities of various  kinds of treatment
and  decide the effluent  limitation.  Particularly  it seems  that  biological oxygen
demand is not a problem in ocean waters because there exists an abundant supply of
oxygen available for degradation of municipal wastes.
     Is  there  any  possibility  to reconsider  the  effluent limitations  and their
enforcement to take in account of water quality standard in each  case particularly in
the case of ocean outfall.  For such treatment works the decision  must be made on a
case by case basis  as  to  whether any attainable percentage removal level  can  be
defined.

5.2  OCEAN DUMPING
     We understand that it is the  policy of the U.S. EPA to regulate the dumping of
all types of materials into ocean waters  and to prevent or to regulate strictly the
dumping or other discharge into  ocean waters of any material in quantities which
would adversely affect human health, welfare, amenities, or the marine environment,
ecolo'gical potentialities, or plankton, fish, shellfish, wildlife, shorelines or beaches.
     It seems that the  Section 403 (c) of the 1972 Act requires that application for
permits for the  dumping or other  discharge of any  materials into the marine
environment be evaluated  on the  basis of the impact of the materials on the marine
environment and  marine ecosystems, on the present and potential uses of the ocean,
and on the economic and social factors involved.
     The regulation of ocean dumping may  vary according to the types of waste
materials as follows;
(1)  The dumping of some types  of  waste materials into the marine environment is
     prohibited and  will not be approved by U.S.  EPA  under any circumstances.
     Such prohibited waste materials  are identified as follows;
      i)  High-level radioactive wastes
     ii)  Materials produced for radiological, chemical or biological warfare.
     iii)  Materials  insufficiently  described in terms of their physical, chemical or
         biological  properties  to permit  evaluation  of their  impact  on marine
         ecosystems.
(2)  The disposal of some types of waste  materials  into the marine environment is
     strictly regulated  to  prevent or minimize known or adverse effects on  the
     aquatic ecosystem or human health and welfare. These materials and limiting
     concentrations and conditions upon  the disposal of these materials are given as
     follows in  the criteria;  and  these  materials will be  considered as trace
     contaminants when they are present in sewage sludge.
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      i)   Organohalogen compounds
      ii)   Mercury and its compound:      Solid state:    Less than 0.75 mg/kg
                                        Liquid state:   Less than 1.5 mg/kg
     iii)   Cadmium and its compounds;    Solid state:    Less than 0.6 mg/kg
                                        Liquid state:   Less than 3.0 mg/kg
     iv)   Total oil
          Do  not produce visible surface sheen  in  an  undistributed water sample
          when added at a rate of one part waste material to 100 parts of water.
(3)  The  disposal of some types of waste materials in subject to less strict regulation
     and  permission because of the minimal  adverse environmental effects to be
     anticipated.
      i)   Waste materials containing none of the materials mentioned above (1), (2)
          with limiting permissible concentration may be regarded  as none-toxic in
          the marine environment.
      ii)   Solid waste
          Solid waste of natural minerals or materials compatible with the marine
          environment may be generally  approved for ocean disposal.
     iii)   Disposal of dredged materials
(4)  Materials requiring special care are as follows;
     Arsenic    Lead       Copper      Zinc     Selenium
     Vanadium  Beryllium   Chromium  Nickel
     in these cases it is obliged  that the  applicant can demonstrate that the material
     proposed for disposal  meets  the  limiting permissible concentration of total
     pollutants considering both the pollutants in the waste material itself and the
     total mixing zone available for initial dilution and dispersion.
     Under these regulation for ocean dumping of waste materials I assume that in
U.S.A. suggestion must be made so that the general permit  could be used to allow
the  dumping  of municipal sludge, because  I  am told that  there were  many
experiences  for dumping of municipal sludge into marine environment without any
impact for the cited environment.
     Ocean dumping in Japan is prohibited as a rule except for some cases when
dumping is permitted by the regulation  relating to the Marine Pollution Prevention
Act  1970 and policy of Japanese Government on this  matter is going in the same
line  as in U.S.A. At the moment ocean dumping of municipal sludge in Japan is
almost impossible because of strong opposition from fishermen, but some members
of  the  scientific   community  including  fishery  science   are  contended  that
biodegradable  organic matter such as municipal sludge with some nutrients will not
adversely  effect on marine environment  or  plankton  or  fish.  It  is  extremely
necessary  to conduct large-scale research demonstration in this field, but actually we
have now in  Japan strong opposition even for such experimental research works.
     I am told that a permit for dumping of  materials into  the ocean as part of
research into the impact of materials on the marine  environment may be issued by
U.S.  EPA Administrator when  he determines  the scientific merit of the proposed
project outweighs the potential damage that may occur from the  dumping under the
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following conditions;
 i)   The  applicant provides to  the  Administrator a detailed statement of the
     proposed  project,  including  an  assessment of  the  probable environmental
     impact carrying out the project.
 ii)   There is public notice and opportunity for public hearing.
iii)   Research permit will  be issued  for  no longer than  18  months, but may be
     renewed after review by the U.S. EPA Administrator.
     The  research permits  of  ocean dumping  may  be  good idea to solve our
problems in Japan demonstrating the actual examples. We shall be much obliged if
you will show  us some examples  of research permits in which research works on
ocean dumping of municipal sludge have been carried out.

6.   PRETREATMENT
     Pursuant to Section  307  (b) of the  Federal Water Pollution Control Act
Ammendments of 1972 the pretreatment standards for introduction of pollutants
into publicly owned treatment works can be described in terms of the following
pollutants;
(1)  Pollutants which are determined not to be susceptible
(2)  Pollutants which would interfere with the operation and maintenance of such
     treatment works
This means that pretreatment standards are designed to achieve both to prevent the
discharge of pollutants which pass  through such works inadequately treated  —
incompatible — and to protect the operation of publicly owned treatment works —
prohibited  wastes —.
     I realized that the  definitions of compatible pollutant, incompatible pollutant,
joint  treatment works, and major contributing industry are very important to
understand  practical implementation of the  1972 Act.  It  should  be noticed that
compatible  pollutant will  be the pollutant identified in  the National Pollutant
Discharge Elimination System (NPDES)  permit if  the publicly owned treatment
works  does remove  such  pollutants  to a  substantial degree (about 80% removal)
including COD, TOC, P, N, Fats, Oil and Grease. It should be noticed also that under
the NPDES all  point source including publicly owned treatment works to  must
obtain a permit for the discharge of wastewater to the navigable waters of the
United States, but permits will not be required for industrial wastewater discharging
into public sewers, and  the effluent limitations for a pollutant in the discharge from
a publicly owned treatment  works will be  individually determined by the regulating
agency  being based  upon  Secondary  Treatment  Information,  Toxic Effluent
Standards, Water Quality Standard whichever the most stringent limitation.
     Under  these  circumstances  it is  very  important  to have strong and  clear
pretreatment policy  considerations.. Judging from the definition  of incompatible
pollutants it may be recognized that  incompatible  pollutants will be materials to
inhibit biological activities and to give accute or chronic effects to aquatic life. I do
agree  that generally speaking the incompatible pollutants in amounts greater than
would be permitted if the user discharged directly into navigable waters should be
confined into the in-plant  site,  and  accordingly the pretreatment  standards for
                                  -  384  -

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incompatible pollutants  are  the  same as the standards for direct  discharge into
navigable waters. Pretreatment is required for incompatible pollutants to the levels
of best practicable control technology currently available  as defined for industry
categories under Section 304 (b) of the 1972 Act.
     Incompatible pollutants including toxic effluent will not be designed to protect
sewer  systems  as  a general  principle, but to  protect aquatic life  in the navigable
waters  concerned from  both acute  and chronic  impacts,  but we have to pay
attention that such incompatible  pollutants as heavy metals may accumulate in the
sludge generated by the publicly owned treatment works.
     Recently we have been doing experimental works of sludge application on farm
land, and in doing so we have realized that farmers are so nervous to apply sewage
sludge on their farm land due to  heavy metal  accumulation in the soil.  From these
points of view it is  recognized that we  should  review pretreatment standards and
should keep such materials as heavy metals in the sludge to such a degree that sludge
may be applied safely to farm land.
     It seems that the Pretreatment Standard is deficient in that it fails to impose
specific numerical limitations on the discharge of pollutants of prohibited waste and
also incompatible pollutants. Of course it can be realized that the  necessary degree
of prohibited wastes and incompatible pollutants in each treatment works depends
on  the concentration of pollutant in the treatment works itself rather  than  the
concentration of each user's effluent. It will,  however, be quite required that a
national pretreatment standards should be workable and enforceable and for that
purpose it must be prescribe  the  permissible concentrations of particular pollutants
of the user's effluents. Otherwise the  user will not know what step he must take to
comply with the pretreatment standards.
     It is  my understanding that joint treatment  of  industrial and municipal
wastewaters in  the same  plant is generally a desired practice, because there are some
advantages which are in the terms of increased flow which can result in reduced ratio
of peak to  average flows, savings  in capital and operation and maintenance expenses
due to the  economics of large-scale treatment facilities and better use of manpower
and land etc.,  and joint  treatment of domestic sewage  and adequately pretreated
industrial  wastewaters is  encouraged where  it is the economical  choise including
social costs.
     Under  stringent pollution  control  policy  being taken in Japan, there is a
tendency that municipalities  will  be unwilling to receive  industrial  wastewaters into
public sewers  due to difficult  job  relating  to inspection  and  monitoring, but
industries will be willing to discharge their wastewaters into public sewers.
     The fact that an industry chooses  to use  a public  sewer  system rather than
discharging  his wastewater directly  into the  navigable  waters should not involve
getting away from penalty,  and the industry  concerned, of course, should provide
his   own pretreatment  plant provided  with  currently best  practicable  control
technology  and  also  should pay the  appropriate  money to  the municipality
concerned according to polluters pay principle, PPP
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7.   USER  CHARGE
     Section 204 (b) (1) of  the  1972 Act prohibits  Federal grant assistance to a
municipality unless  it has adopted a proportionate user charge  system to defray
costs associated with operating and maintaining a facility including replacement. In
the Federal guidline relating to  user  charges for  operation and maintenance  of
publicly  owned  treatment works, it  is written that Section (b) (1) of the Act
provides  that after March 1,  1973 Federal grant applicants shall be awarded grants
applicants only after the Regional Administrator has determined that the applicant
has adopted or will adopt a system of  charges to assure that each recipient of waste
treatment services will  pay its proportionate share of the cost  of  operation and
maintenance including replacement. The  intent of the  Act with respect to user
charges is to distribute  the cost  of operation and maintenance of publicly owned
treatment  works  to the  pollutant source  and  to  promote  self sufficiency  of
treatment works with respect  to operation and maintenance costs.
     It seems that  the  problem  is compounded  because of an opinion  of  the
Comptroller Genera] which prohibits U.S. EPA from funding new projects in areas
where  municipalities are utilizing ad valorem  tax  systems to finance  wastewater
treatment operation and maintenance charges.
     During the Third Conference there was a discussion  presented by Metropolitan
Sanitary  District  of  Greater  Chicago, and I quote:  "Under our present  system, we
collect revenue  from an  ad  valorem property  tax  together with  an industrial
surcharge when  the  discharge of an industry exceeds 3,650,000  gallons within a
12-month period. This method of funding has proven successful and the merits of
changing this proven method  are dubious. Another problem is presented in attempts
to measure  the discharge  of  each domestic user to achieve a fair allocation of the
cost of treatment.  The Metropolitan  District of Greater Chicago plus  116 other
municipalities.  It is  a practical impossibility to  monitor  the discharge  of every
domestic  user in the Chicago  metropolitan  area. One suggested alternative is  to
correlate water consumption  with discharge to the sewers and base the user charge
on the volume of water consumption.
     This might be feasible in  many of the 116 municipalities outside the City of
Chicago  where water  is  metered but  within Chicago  there  are about 350,000
nonmetered users. These users,  mostly  residential, are charged a flat rate for water.
Under a direct user charge, about 350,000 water meters  would have to be installed
within the City of Chicago at a cost of approximately 60,000,000 dollars. The cost
of reading these additional 350,000 meters is estimated to be somewhere around
3,000,000.00 dollars a year.
     The contemplated user charge assumes that the sole function of a district is the
collection and treatment of waste. The Metropolitan  Sanitary District, however, is
also charged by statute with  the additional duties of flood  control, maintenance of
waterways,  and  the abatement   of  the  pollution of  waters from  which any
municipality might receive  its water supply. This, of course, means the protection of
Lake Michigan. These additional responsibilities would have to be funded by the ad
valorem tax, so that even if a user charge  is invoked,  it would still be necessary to
levy the ad valorem tax.
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     There would also exist the  problem of  enforcing the user charge if a user
become  delinquent. When you consider that  the Metropolitan Sanitary District
serves 5.5 million people and 11,000 industries in the metropolitan Chicago area, it
is easy to see that we would  be forced to spend a great deal of time in collecting or
attempting to collect deliquent charges. Yet, this would be only a small part of the
total cost of administration of user charges. The major expense would be in the
routine billing and collection from literally hundreds of thousands of users. Now —
in our present tax system, we succeed in collecting 89% of the tax levy. This money
is forwarded to us by the county collector automatically and routinely without cost.
The difference here speaks for itself.
     How then the user charge benefit the taxpayer? I suppose it is possible that a
system can be devised  where  the cost for each user will be more proportionate than
it is now. Bear in mind, however,  that a proportionate share  under the user charge
will probably mean a greater  cost  to the average homeowner than he is now paying
in taxes, when you consider the administration and collection costs, and a collection
experience that cannot be expected to approach 89%.
     The  Metropolitan Sanitary District is  not  taking a  hostile position to the
Federal  requirements.  We  are simply  advocating  that  our present method  of
financing by an ad valorem property tax coupled with an industrial surcharge meets
the intent of the EPA standard for  user charge."
     It seems that the presentation by Metropolitan  sanitary District of Greater
Chicago does tell us whole story  for user charge system in the case of cities  with
proud history of sewage works operation of their  own.  And it can not  be helped to
say that  in these cases it would be reasonable to give such cities discretion utilize
modified user charge system to  pay their share of operation and maintenance costs.
     The basic principle of user  charge  system  in  Japan which is suggested by
Ministry of Construction will be described as follows;
(1)  Construction cost of facilities  for sewerage and  sewage treatment  shall  be
     covered by public expenses including grant, public loan, local tax and so on.
(2)  Operation and  maintenance  cost of facilities excluding cost  of  replacement
     shall be paid by the revenue from the user charge.
(3)  User charge should be divided into two classes.
     i)   Domestic user charge
     ii)   Industrial user charge
     Domestic  user charge  shall  cover  only operation  and maintenance  cost
     excluding replacement of facilities and be  decided  by quantity discharged into
     sewer.
     Industrial user charge shall cover not only operation and maintenance cost but
     also cost of replacement by reservation of depreciation account. That portion
     should be  recovered in accordance with so  called Polluters Pay Principle and  be
     decided by quantity and quality requirement discharged into sewer.
(4)  User charge system on a graduated scale shall be taken in order to economize
     water  consumption and so  quantity discount to large volume users will not  be
     acceptable.
                                   - 387 -

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(5)  Water consumption with discharge to the sewer should be correlated by water
     meter and water consumption by well from ground water with discharged to
     the  sewer  shall  be  estimated on  the  basis of pump capacity and its running
     hours.
     Philosophy of  these  basic principle is: pollution should be stopped  and
controlled  at  the  source.  One  of the most effective methods of reducing the
pollution load into the sewer caused by industrial effluents is to make a user charge
which is  based  on a  sliding scale in accordance with their quantity and quality. In
this  way an incentive can be given to the trader to reduce his discharge of waste
from his factory and in doing so to pay less user charge, by re-using water, by
making minor modifications in manufacturing processes, by recovering by-products
or by some means. Some remarkable results have been achieved in this way with
profit to the trader,  and with great advantage to sewage treatment  operation, and
with considerable resulting contribution to the national  economy including water
resources. Recently experiences of sewage works operation in Osaka City, Japan,
have shown the remarkable reduction of industrial effluents into the public sewer by
employing  the suggested user charge in terms of industrial effluents. With regard to
water resources investigation the Ministry of Construction published that by  1985
the  1970 output of water conservation works in  Japan will be needed to be  about
1.5  times  as  a  nation-wide. The major water  deficiency  areas  are  in  large
metropolitan areas such as Tokyo, Osaka, Nagoya, Kobe, Fukuoka, Sendai etc., and
even for the  deficiency  areas the high costs of building dam and transmission may
link  that the  transfer of water from remote dam site has no obvious advantage from
view points of costs.
     The future water demand estimated by the Ministry of Construction is shown
in the Table 7.1. Firm long-term forecast are not be available, but there seems to be
obvious limit to the  growth in demand for water from water  undertakers, both to
meet increased  domestic consumption consequent upon rising social living standards
and  to serve the growing demands of industry. It has now been realized that the fast
increasing consumption of water, both domestic and industrial, will make imperative
a  much  greater reuse of water and  also  economical  usage in both domestic and
industrial purposes in terms of consumption in nearly all over Japan.
     Under  these  circumstances  it  appears  that  the user  charge  system  on  a
graduated scale will be more  effective  in  such a way  that  the users including
domestic and industrial consumers may try to save water consumption to pay less
user  charge, and in doing so an incentive can be given to dischargers also.
     Each house is provided with its own water meter in  almost every municipality
in Japan and water  consumption  with sewage  discharge into the  sewer can be
correlated.  In this connection there is no difficulty to employ user charge system for
us. Recently  the charge system in .terms of water and sewage has been revised in
Tokyo Metropolitan  Government as shown in Table 7.2..The basic principle of this
revision is going in the same line as mentioned above.
     In  this  cases of water consumption with  discharge  of same amount, say
monthly  consumption,  10m3,  20m3, 50m3,  100m3,  1,000m3,  calculation of
water and sewage charge in each case under Tokyo Metropolitan revision is shown in
                                   -  388

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                            Table 7.1  Future Water Demand Estimation
                                                            (0.1 billion cub. m. per annum)



Hokkaido
Tohoku
Kanto
Hokuriku
Tokai
Kinki
Chugoku
Shikoku
Kyushu
Total
1970

Domestic
3.6
9.1
34.0
2.0
10.6
21.2
5.5
2.6
7.1
95.7
Industrial
9.6
16.1
33.0
10.2
38.7
28.4
16.1
9.0
13.5
174.6
Agricultural
49.7
129.5
83.3
28.4
46.4
44.5
48.8
23.1
69.9
523.6
Total
62.9
154.7
150.3
40.6
95.7
94.1
70.4
34.7
90.5
793.9
1985

Domestic
8.6
17.5
69.0
4.6
27.1
39.7
12.6
6.2
21.3
206.6
Industrial
32.4
46.5
65.8
20.6
64.2
46.3
30.8
22.8
41.4
370.8
Agricultural
56.9
143.8
87.5
28.9
52.8
42.8
52.2
26.4
94.2
585.5
Total
97.9
207.8
222.3
54.1
144.1
128.8
95.6
55.4
156.9
1,162.9
Table 7.2   List of Water Charge and Sewer User Charge in Tokyo Metropolitan Gove.nment
                             List of Water Charge (Yen)
Old
Basic charge
100
100
120
120
140
500
500
12,000
Range
(n/)
0~8
9~18
19~30
31~50
51 -100
101~200
201 ~ 1,000
1, 000 ~ over
Specific
charge due
to quantity
0
20
25
28
45
55
68 v
75
New
Basic charge
300
300
400
400

500
2,400
17,000
Range
(m3)
0~10
11 ~20
21-30
31-100

101 —200
201-1,000
1, 000 ~ over
Specific
charge due
to quantity
0
60
75
90

120
150
180
                                          389

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                       List of Water Charge (Yen)
Old
Basic charge
80







Range
(m3)
0-8
9 over






Specific
charge due
to quantity
0
10






New
Basic charge
100
100
300
1,200
2,950
7,450
23,900
56,450
Range
(m3)
0~10
11—20
21~30
51 ~ 100
101 ~200
201-500
501-1,000
1,000 over
Specific
charge due
to quantity
0
20
30
35
45
55
55
75
Table 7.3  Water and Sewage Charge as shown in Yen/cub, m. in Tokyo
Water Charge

10m3
20m3
50m3
100 m3
1,000 m3
Old
14.00
18.50
23.60
34.50
63.71
New
30.00
45.00
71.00
80.50
142.05
Sewer User Charge
Old
10.00
10.00
10.00
10.00
10.00
New
10.00
15.00
28.00
40.50
80.25
                                  390  -

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Table 7.3.
     It seems to me that the sewer user charge system can be expanded to apply to
pollution charge system in overall water pollution control. Levying charges on those
who discharge wastewater into public water body in proportion to the quantity and
the nature  of the wastewater. By and large the charge mechanism provides just such
an incentive. Instead of having water as a natural resource  of infinite capacity, we
find ourselves in a position where water is a limited resource  which urgently needs to
be  managed. The  preparedness  of industries  to reduce their waste effluents was
strongly  stimulated by  the fact  that  the annual charge levied for financing water
quality management is directly related to the volume and the nature of the effluent.
This made  it economically attractive for any industry to try and find a solution to
the problem of how to limit the amount of waste to be discharged.
     Pollution should be  reduced in the point where  the costs of doing  so  are
covered by the benefits from the reduction of pollution.  What is required, ideally, is
some incentive to polluters to reduce pollution up to the point where the costs to
them of further pollution abatement would be greater  than damage done by the
pollution. This is why the ideal means of avoiding  excessive pollution  at least in
principle, is to make the pollution pay a charge corresponding to  the damage done
by his pollution.
     This principle  is attractive and justified,  not  only  does it associate the cause
with the consequence, but it has also  become clear from practice that having to pay
a  charge makes  an industry much  more  pollution-minded. This  circumstance,
combined with a strong permit policy, may  lead to a considerable reduction  of the
pollution and may often change  a potential  pollutor  into a supporter of water
quality management.
     Management of water resources should  take into  account social,  economic,
scientific and technical aspects and  the sewer user charge system would be a key to
water management by expanding it to pollution charge system.

8.   INDUSTRIAL COST RECOVERY
     Pursuant to Section 204 (b) (3) of the  1972 Act, "The grantee  shall retain an
amount  of the revenues derived from the payment  of costs by industrial users of
waste treatment services, to the extent costs are attributable to the Federal share of
eligible   project costs  provided  pursuant  to  this  title  as  determined by  the
Administrator, equal to  (A) the amount of the non-Federal cost of such project paid
by  the grantee plus (B)  the  amount, determined in accordance with regulations
promulgated   by   the  Administrator,   necessary   for future  expansion  and
reconstruction of the project, except that  such retained amount shall not exceed
50% of  such revenues  from  such  project.  All Revenues  from such project  not
retained  by the grantee shall be deposited by  the Administrator in the treasury as
miscellaneous receipts.  That  portion of the  revenues  retained by the grantee
attributable to  clause (B)  of the first  sentence of this paragraph together with any
interest   thereon shall  be used solely for the purpose  of future expansion and
reconstruction of the project."
     It seems that a grantee must elect to compute industrial cost recovery amounts
                                   - 391

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annually on projects completed within an established accounting period. Such fund
also  must be segregated in  special accounts and accounting procedures must be
established to permit audit at any time during the recovery period.
     It will be possible to determine what percentage of the capacity of the sewage
treatment  plant is  attributable  to any industry, but  if there are many major
contributing industries  which discharge their wastewater into sewage  treatment
plant, such a determination  can be • an immense even if not an impossible task. In
these cases  cataloging  of industries for the purpose of cost proportioning would
require the sewage works authority concerned to keep record on great amount, and
the authority would have to  know when there is a change in ownership,  when one
goes out of business, or when a new one comes, when one changes its manufacturing
processes or raw materials to be  treated in its factory,  continuously revising each
business' contribution.
     I would like  to have informations on this matter and good examples in practice
which has been carried out satisfactorily with the  requirements of Section 204 (b)
(3) of 1972 Act.
                                    392

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                            Fourth US/JAPAN Conference
                                     on
                            Sewage Treatment Technology
                                  Paper No. 7
WET  WEATHER  FLOW  AND  COMBINED SEWER
     OVERFLOW  ABATEMENT TECHNOLOGY
                  October 29, 1975
                  Washington, D. C.
               Ministry of Construction
                Japanese Government

                      - 393 -

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WET WEATHER  FLOW AND  COMBINED SEWER OVERFLOW ABATEMENT
TECHNOLOGY
  K. Saito and M. Kashiwaya, PWRI, Ministry of Construction
1.  Sewer Served Area and Status Qua in the Sewer Collection System in Japan  . .395

2.  Investigation on the Storm and Combined Sewer Overflow in Japan     .    396

3.  Quality of Combined Sewage and Urban Storm Water . .    	393

4.  A Proposal of Storage Tank ,              	      .        ...-399
                                  394

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        WET WEATHER FLOW AND COMBINED SEWER OVERFLOW
                        ABATEMENT TECHNOLOGY

1.   SEWER SERVED AREA AND STATUS QUO IN THE SEWER COLLECTION
    SYSTEM IN JAPAN
     In  1974, 426 municipalities were undertaking sewage works in Japan. In 1975,
60 municipalities are launching sewage works.
     In  1974, an area of 2,080 km2 was sewered, accounting for 25.5% of the urban
area in Japan. The population served by sewers are estimated to be 38 million.
     In  1972, Ministry of Construction made a  survey on the sewer collection sys-
tems. 316 municipalities responded to our inquiries. The results of the survey are
shown in Table 1. It is found that  104 municipalities employed the combined sewer
systems, while 96 cities used the separate sewer systems. There were 81 cities where
the sewer systems were mainly of the combined type and partly of the separate type.
Most of these cities applied  the combined sewer systems to the urban area and the
separate type to the suburbs.
     In  35 cities, major  portion of their service area had separate sewers  with  the
remaining portion served by combined sewers. This type of sewer systems are classi-
fied into two; one in which separate  sewers are  used in steep areas, while combined
sewers in plane  areas, and another in which the newly developed residential zones in
the suburbs use separate  sewer systems while the most old urbanized areas are re-
maining unsewered. In the areas covered by the  combined sewer systems,  there live
26.31 million or 70% of sewer served population.
     Table 1  shows  a comparison  between Japan and the United States  as to the
combined sewer systems.
     In  Japan, the cities  employing the separate sewer systems have been increasing
as combined sewer systems was criticized for its combined sewer overflow problems.
Ministry of Construction also has been recommending the separate sewer systems for
the purpose of water pollution control.
     If  the unsewered cities will be  arranged with separate sewer systems, Japan's
sewer systems will reach almost the same level as  in the United States.
                                  -  395 -

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2.   INVESTIGATION ON THE STORM AND COMBINED SEWER OVERFLOW
     IN JAPAN
     Since  1967, Public Works Research Institute, Ministry of Construction has
made investigations on the storm and combined sewer overflows.
     The data concerning rainfalls, storm water and water quality for the 1867~69
period were collected from five cities ~ Tokyo, Nagoya, Toyohashi, Kyoto and Gifu.
The data collected were aimed at the preparation of design manual for new sewerage
plans and the evaluation of the existing combined sewer systems. The areas investi-
gated were each different in population  and land use from others.
     The survey also included the examination of applicability of the rational me-
thod, measurement of inlet time and time of concentration, investigation of runoff
coefficient, actual quality  of sewage in the wet-weather conditions, and change  in
the rainfall runoff attendant on urbanization.
     Although the surveys  were completed in 1969, from 1970 till now the observa-
tion  of rainfalls and rainfall runoff has been carried out in the catchment area  of
the Yabatagawa, Tokyo. In the guidelines for the sewerage which were established  in
1972 by Japan Sewage Works Association, it is recommended that the unsewered
areas should be served by separate sewer systems, because combined sewer system is
liable to cause storm water overflow problems leading to water pollution. But, the
guideline leaves how to improve the existing combined sewer system over for the
future study.
     For this reason, a survey on the improvement of the combined sewer system  or
its alternatives has been conducted since 1973. So far, the survey has tackled the
problems incidental to the overflow from the combined sewer, flow rate, water
quality and  characteristics  of  combined  sewage and storm water discharge, assess-
ment of alternatives proposed, and preparation of a conceptual  plan for a storm
water storage tank with the Yabatagawa catchment (Tokyo) taken as a model.
     In 1975,  engineers from  Ministry of Construction, local  governments and
Japan Sewage Works Agency  rallied to establish "Committee on Combined Sewer
Overflow Problems." The purposes of the Committee are to let its members investi-
gate  the sewer systems in their respective cities,  to have them exchange the informa-
tions obtained with each other, and thereupon to study how to improve the com-
bined sewer systems in the  respective cities. The Central Government is in a position
to appraise the  achievements of each city, while the Committee, which appripriates
the outlays for the collecting of data necessary for the Central Government to persue
the problems, is going to undertake research activities from 1975 till 1980.
     The results of  the investigation will be used not only as data for the Govern-
ment's long-term projection, but also for the planning of each city's combined sewer
improvement programs and preparation of the design manual for sewage system.
     On the other hand, the Tokyo Metropolitan Government has made various in-
vestigations  along the Yabatagawa and  the Momozonogawa. The  themes for the
investigations include the examination of infiltration loss in the urban area, applica-
bility of RRL method, development of modified RRL method, examination of the
storm water drainage system, preparation of pollutant discharge model, etc.
                                   - 396  -

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     In 1975, Tokyo Metropolitan Government relocated the observation station to
Ogu District for continued survey. The District is a plain, and storm water is drained
by pumping. The sewerage always carries a large amount of stagnant water. Hence,
the results of the survey may become different from those in the Yatabegawa and
the Momozonogawa.
     Osaka Municipal Government planned a combined  sewage (storm water) sedi-
mentation tank  on  the  occasion of the repairs of the Nakanoshima Pump Station
located at the center of the city. The tank will be composed of six basins each meas-
uring 3.5  m in width,  20.2  m in length and 5.2 m in height. Two out of  six were
completed in 1975. Osaka Municipal Government will use these tanks for the meas-
urement of the volume and quality of influent and examination of the feasibility of
the similar tanks which will be planned and constructed from now on.
     The results of survey, such as conducted by local governments will be also sub-
mitted to the Committee on Combined Sewer Overflow Problems.
     Water pollution problems due to  storm water discharge in the urbanized area is
not solely developed by combined sewer overflow.
     In the old cities, dry-weather flow has been increased with the progress of ur-
banization, which has resulted in a shortage of sewer capacity. Namely, in dry weath-
er conditions,  raw sewage is liable to be delivered to the receiving waters  without
treatment or even when the rainfalls  are not  so severe, overflows have  happened.
     Consideration to the alternatives to solve the combined sewer overflow pro-
blems in these cities should also cover the measures to make up the shortage  of sewer
capacity. Sewer separation will become one of effective measures, except  in those
heavily build-up areas which have high population density. In most of oldest cities,
the conversion  of the existing combined sewer systems into the separate one is al-
most impossible as various restrictions are present,  and alternatives may have to be
taken up. There are many alternatives proposed, and their practicability should be
examined from various aspects.
     The results of this kind of surveys conducted by U.S. EPA are very informative
to us.
     In the separate sewer systems on the other hand, urban storm water itself pre-
sents a serious pollution problem. Also, excessive infiltration into sanitary  sewer
systems is concerned about since it results in overloading to sewage treatment facili-
ties. In the existing separate sewer systems, storm water flow mainly in gutters,
natural water courses, etc. If the urbanization advances  in the future, storm water
runoff will overrun  the capacity of these facilities.  It  will be therefore necessary to
drastically reconstruct the storm drainage facilities, install a basin in the city in order
to pool storm water temporarily. In some case porous pavement and the  like which
decrease the rainfall runoff coefficient should be incorporated.
                                   - 397 -

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3.    QUALITY OF COMBINED  SEWAGE  AND URBAN STORM WATER
     Public Works Research Institute has investigated the quality of combined sew-
age in Tokyo, Nagoya and Kyoto.
     Table 2 shows  test locations. The results of surveys are shown in Table 3 ~ 5.
     According to  a  U.S. EPA  survey report*  the quality of combined  sewer
overflows are that of raw sewage or its half. In Japan, the tendency is almost the
same. It is interesting to note that the quality is nearly the same for all that the way
of living  and rainfall conditions are quite different between the two countries (Table
6).
     In the Yabatagawa District in Tokyo, the "first flush" is found noticeable at a
rainfall of 10 mm/hr to 20 mm/hr, particularly when heavy downpours are seen in
the beginning (Fig.  1).  At 3 to 5 mm/hr of rainfall, it is not found precisely (Fig. 2).
     In the case of high-intensity rainfall, dilution phenomenon is noticed (Fig. 3).
     If two consecutive rainfalls are present, "first flush" occurs in second railfall,
even when their interval is short especially the second one is heavy (Fig. 3, Fig. 4).
What is noticeable in the first flush includes BOD, SS, etc., and nutrients, total-coli.
are rarely seen.
     In 1975, surveys on combined sewage have being conducted in 11 largest cities;
Sapporo,  Tokyo,   Kawasaki,  Yokohama,  Toyohashi, Nagoya,  Kyoto,   Osaka,
Hiroshima, Kitakyushyu, Fukuoka. As regards the storm water discharge into the
separate  sewer system,  surveys were carried out in Gifu, Kobe and Yamagata for the
purpose of contrasting  them with the combined sewage. Table 7 shows the test loca-
tions and  the results in Table 8 ~ 10.
     Storm water discharges were found seriously polluted, and ocassionally these
quality were similar to raw sewage. Such Heavy metals as Zn, Pb, were also included
considerably in storm  water discharge  (Fig. 5).  The mean value was  poorer than
the secondary effluent, showing little difference from the survey results in  U.S.A.
(Table 11). In Japan, gutters and natural small water courses have been used for the
purpose of drainage where the separate sewer systems is applied. In dry weather con-
ditions, pollutants deposite in them and are scoured away with rain water. This has
been the major cause of the pollution of storm water from the separate sewer system.
     In 1975, the survey on urban  storm water has been continued in Kobe.
     The  total rainfalls  in Japan are 1,500 mm/year to 2,000 mm/year, and typhoons
visit,  bringing  about heavy downpours. But generally,  Japan's largest  cities have a
high population density and use large quantities of water.  Accordingly, the  annual
BOD and SS loading of the effluent from the sewage treatment plant are much more
than those in the combined sewer overflow which is directly discharge into  the re-
ceiving waters.
     Namely, the effluent from the sewage treatment plant is always imposing higher
loading on the receiving waters. Table 12 is the results of an estimate with a down
town in Tokyo taken as a model.
     It is clear from Table 12 that BOD  loading of the combined sewer overflow
   * F.J.  Condon  "Storm  and Combined Sewer Abatement Technology  in  the
U.S.A. - An Overview -" EPA, Feb.,  1974.
                                     398

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accounts for no more than 20%.
     Most of nutrients are contained in sew ige treatment plant effluents.

 4.   A PROPOSAL OF  STORAGE TANK
     There are a lot of proposals for overcoming the combined sewer overflow pro-
 blems.
     One such example  is a storage tank. It is believed to have the following advan-
 tages.
 1)   The structure is simple and easy to operate.
 2)   The conventional sewage treatment technology is applicable.
 3)   Stage-wise construction is possible, and takes effect soon as local modification
     of sewage treatment facilities will do for the purpose.
 4)   Capacity of the existing sewer can be increased.
 5)   Wide fluctuation of storm water flow can be controlled and equalized.

     Particular emphasis may be placed  on the last merit since Japan often is hit by
 heavy downpours.
     Pulbic  Works Research Institute estimated the effects of the combined sewage
 storage tank with the Yabatagawa District, Tokyo as a model.
     The District lies northwest  of Tokyo, and covers an area of 541 ha with the
 combined dewer systems. The result of estimation are as follows; in this district, the
 calculated BOD and SS  loadings are as shown in Fig. 6 namely, the removal rate of
 BOD and SS loadings consequent upon the discharge of storm water is only 22% and
 28%, respectively.
     By installing three  tanks, 27,000 m3, 54,000 m3 and 81,000 m3, 40% to 70%
 of the annual storm water discharge of 440 mm can be storaged. The storaged storm
 water  is sent to the sewage treatment facilities in dry weather and then discharged
 into the receiving waters after secondary treatment.  The results  of this study indi-
 cates,  the removals  of BOD and SS loadings  are from 60 to 70%  and 70 to 80%
 respectively as shown in Fig. 7 Another benefit is the reduction of annual overflow
 frequency which is reduced to 42, 16 and 11 as against the theretofore 78.
     Even if the district  were served  by separate sewer system, it will still deliver
 pollutants at  an annual rate of  118 tons in BOD and 391  tons in SS as the storm
 water discharge is polluted.
     The amount is  tantamount  to the installation of a storage tank with a capacity
 of 58,000 m3
     Unfortunately,  however, it is hardly possible to find out an open space allowing
 the construction of such a large facility.
     It is therefore concluded that the storage tank should be constructed beneath
 public facilities such as  park, parking lot, open space necessary at the time of earth-
 quake etc. In this way, precious space can be used effectively.
                                      399  -

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Table  1   Relative Use of Combined Sewers

Municipalities
Combined sewer
Combined and partialy separate
Separate and partialy combined
Separate sewer
Total
Area (km2)
Combined sewer
Separate sewer
Total
Population
Combined sewer
Separate sewer
Total
Japan

104
81
35
96
316

1,526
552
2,078

2,631
1,166
3,797
%
33
26
11
30


73
27


69
31
31
U.S.A.

1,329


12,000






36,236
89,534
125,770
%
10


90






29
71

                 400  -

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Table 2   Test Location (Combined Sewer)
City
Tokyo
Kyoto
Nagoya
Nagoya
Test location
Yabatagawa
Chubu-daiichi
Tamitsu
Chitose-nambu
Drainage area
(ha)
540.6
67.8
51.4
81.2
Population
120,000
17,000
9,900
12,300
Land use
Residential,
semi-industry
Residential
Residential
Semi-industry, harbar
commercial
              -  401  -

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                                     Table 3   Characteristics of Combined Sewage (1) (Yabatagawa, Tokyo)
                                                                                                                                     Unit: mg/C
\s
BOD
S-BOD
T-S
ss
VTS
T-N*
T-P
July 31, 1972
Sample
No.
61
30
30
61
30
16
16
Max.
353.0
63.0
886.0
686.0
274.0
17.3
2.88
Mean
94.2
29.0
569.0
340.5
142.7
11.3
1.79
Min.
38.5
15.1
305.0
94.0
51.0
7.3
1.07
September 9, 1972
Sample
No.
56
28
28
56
28
15
15
Max.
158.0
55.8
535.0
214.0
101.0
14.7
2.78
Mean
104.6
37.1
462.9
140.9
66.2
14.2
2.51
Min.
69.4
25.6
324.0
55.0
42.0
13.2
2.15
October 6, 1972
Sample
No.
44
22
22
44
22
11
11
Max.
240.0
66.1
1,076.0
716.0
262.0
33.8
5.92
Mean
102.3
33.6
531.0
251.3
136.7
14.6
2.78
Min.
30.0
18.5
353.0
92.0
42.0
10.0
1.74
July 21, 1973
Sample
No.
35
11
11
35
11
6
6
Max.
317.4
94.3
1,025.0
788.0
463.0
36.1
7.20
Mean
121.7
65.3
548.1
154.9
233.3
24.7
4.56
Min.
62.3
49.8
294.0
32.0
124.0
14.4
2.50
\
BOD
S-BOD
T-S
SS
VTS
T-N*
T-P
July 29, 1973
Sample
No.
70
34
19
70
19
10
10
Max.
147.0
448
475.0
375.0
318.0
29.4
3.10
Mean
89.0
18.3
196.9
86.6
113.3
9.8
1.17
Min.
31.3
10.2
185.0
11.0
56.0
10.1
0.80
August 1, 1973
Sample
No.
60
24
24
60
24
12
12
Max.
246.3
73.8
1,133.0
1,020.0
604.0
11.7
1.90
Mean
88.6
19.4
341.4
221.2
171.3
4.3
0.54
Min.
16.6
10.8
131.0
16.0
58.0
3.7
0.50
August 4, 1973
Sample
No.
83
28
30
83
30
-
-
Max.
177.7
63.4
680.0
475.0
318.0
-
-
Mean
70.1
8.8
142.7
113.8
64.4
_
-
Min.
19.8
10.2
134.0
14.0
59.0
-
-
August 10, 1973
Sample
No.
35
11
11
35
11
_
-
Max.
244.5
88.2
1,092.0
857.0
641.0
—
-
Mean
99.5
36.7
323.5
182.4
174.3
—
-
Min.
19.6
23.5
197.0
21.0
93.0
-
-
\
BOD
S-BOD
T-S
SS
VTS
T-N*
T-P
August 24, 1973
Sample
No.
44
13
13
44
7
-
-
Max.
613.4
238.4
1,935.0
1,768.0
984.0
-
-
Mean
93.0
21.0
192.1
152.2
419.5
-
-
Min.
25.4
8.6
139.0
39.0
104.0
-
-
August 25, 1973
Sample
No.
26
9
9
26
9
-
-
Max.
126.8
52.5
388.0
243.0
234.0
-
-
Mean
101.1
10.5
105.8
118.0
183.9
-
-
Min.
63.2
13.7
185.0
64.0
88.0
-
-
November 10, 1973
Sample
No.
121
121
121
121
121
61
61
Max.
367.5
37.9
819.0
680.0
378.0
26.7
3.14
Mean
45.5
9.3
249.4
162.9
89.7
6.8
0.54
Min.
11.6
3.9
93.0
14.0
31.0
2.4
0.18
Summary
Mean
91.8
35.3
257.5
175.0
163.2
12.2
1.97
Range
11.6~613.4
3.9-238.4
93.0 ~ 1,935.0
11.0-1,768.0
31.0-984.0
1.9-36.1
0.18-7.20
: Kjeldahl

-------
Table 4  Characteristics of Combined Sewage (2)
^\\^
\^
BOD
ss
vss
3 Aug., 67
Sample
No.
29
29
-
Max.
1,176.0
393.0
-
Mean
88.1
214.0
-
Min.
55.3
9.0
-
22 Aug., 67
Sample
No.
23
23
23
Max.
108.8
523.0
106.0
Mean
49.35
298.0
63.0
Min.
22.0
96.0
12.0
31 Aug., 67
Sample
No.
27
27
27
Max.
219.5
525.0
185.0
Mean
71.37
331.0
77.8
Min.
19.2
92.0
20.0
Summary
Mean
69.0
283.0
70.4
Range
19.2-1,176.0
9.0-525.0
12.0-185.0

-------
Table 5  Characteristics of Combined Sewage (3)
        (Tamitsu & Chitose-nambu, Nagoya)
"^^^_
^\
Tamitsu
BOD
ss
Chitose-nambu
BOD
SS
19 July., 67
Sample
No.

40
40



Max.

296.6
4,310.3



Mean

72.6
1,228.8



Min.

4.2
5.8



22 Aug., 67 (1)
Sample
No.

8
8



Max.

59.7
372.5



Mean

84.7
333.6



Min.

5.0
3.2



22 Aug., 67 (2)
Sample
No.

14
14



Max.

80.6
1,289.1



Mean

63.9
455.5



Min.

3.5
4.7



13 Sep. ,67(1)
Sample
No.
19
19
21
21
Max.
51.3
879.2
70.0
514.5
Mean
44.0
411.9
32.3
254.5
Min.
5.7
13.8
7.3
13.3
13 Sep., 67 (2)
Sample
No.
12
12


Max.
16.8
38.5


Mean
55.9
141.2


Min.
7.1
16.8


Summary
Mean
64.2
514.2
32.3
254.5
Range
3.5 ~ 296.6
3.2 ~ 4,310.3
7.3-70.0
13.3~514.5

-------
       Table 6  Comparison of Quality (Strength) of Combined Wastewater Overflows
Type of wastewater and city
Raw Sanitary Flow
Primary Effluent
Secondary Effluent
Combined Sewer Overflows
Atlanta, Ga.
Berkeley, Calif.
Brooklyn, N.Y.
Bucyrus, Ohio
Cincinnati, Ohio
Des Moines, Iowa
Detroit, Michigan
Kenosha, Wisconsin
Milwaukee, Wisconsin
Racine, Wisconsin
Sacramento, Calif.
San Francisco, Calif.
Washington, D.C.
Yabatagawa, Tokyo
Chubu-daiichi, Kyoto
Tamitsu, Nagoya
Chitose-nambu, Nagoya*
BOD5
mg/£
Ave.
200
135
25

100
60
180
120
200
115
153
129
55
119
165
49
71
92
70
64
32
COD
mg/£
Ave.
500
330
55

—
200
-
400
250
-
115
464
177
—
238
155
382
—
-
-
-
SS
mg/e
Ave.
200
80
15

—
100
1,051
470
1,200
295
274
458
244
434
125
68
622
175
283
514
255
Total
coliform
MPN/lOOme
5x 107
2xl07
1 x 103

1 x 107
-
-
1 x 107
-
-
-
2x 106
-
-
5 xlO6
3x 106
3 x 106
—
-
-
-
* 1 storm
                                       - 405

-------
Table 7   Test Location
City
Gifu
Kobe

Yamagata

Test location
Shimizugawa
Hanakuma

Midorimachi

Drainage area
(ha)
106.4
17.2

13.7

Population
24,500
2,700

1,000

Land use
Commercial
Residential,
commercial, office
Residential,
commercial, office
         406

-------
                        Table 8   Quality of  Urban Stormwater
                                    (Hanakuma, Kobe)
                                               (1)

BOD
S-BOD
SS
VSS
T-N*
T-P
Grease**
Total
MPN
3 Sep., 73
Sample
No.
24
14
24
14
14
14
14
14
Max.
980.0
57.6
2,561.0
1,360.0
65.8
1.15
538.3
250,000
Mean
99.4
13.2
756.8
196.0
15.8
0.73
31.7

Min.
13.0
8.5
24.0
13.0
2.3
0.36
1.0
3,100
27 Oct., 73
Sample
No.
51
27
51
27
27
27
27
27
Max.
136.0
43.0
196.0
83.0
10.7
2.06
28.7
77,000
Mean
31.0
11.0
76.4
35.6
3.8
0.67
6.3

Min.
9.5
2.7
6.3
10.0
1.4
0.38
0.1
80
21 Jan., 74
Sample
No.
52
27
52
27
27
27
27
27
Max.
743.0
70.0
2,130.0
959.0
71.0
2.96
138.0
500,000
Mean
104.6
11.9
475.0
179.0
12.3
0.68
22.7

Min.
15.0
5.0
13.4
1.0
1.5
0.32
1.0
2
*:Kjehldahl
Soxhlet method

BOD
S-BOD
SS
VSS
T-N*
T-P
Greass**
Total
MPN
1 Sept., 74
Sample
No.
39
20
39
20
20
20
20
20
Max.
136
6.4
417
86
11.1
1.08
12.4
61,000
Mean
17.7
3.5
97.8
22.0
1.96
0.22
3.8
-
Min.
5.2
2.2
27.2
5.6
0.9
0.12
1.6
400
1 Oct., 74
Sample
No.
70
35
70
35
35
35
35
35
Max.
85.6
13.1
381
111
7.4
0.49
9.7
35,000
Mean
7.4
2.5
78.6
17.7
1.27
0.14
2.40
-
Min.
1.83
1.46
9.4
2.8
0.62
0.05
0.2
1,300
4 Feb., 75
Sample
No.
20
10
20
10
10
10
10
10
Max.
99.7
6.26
630
190
9.12
0.65
41.8
17,000
Mean
65.9
6.1
504.0
156.3
9.33
0.64
35.6
-
Min.
10.3
4.28
24.5
12.0
3.28
0.19
4.0
250
r: Kiehldahl  **: Soxhlet method

BOD
S-BOD
SS
VSS
T-N
T-P
Grease
Total
MPN
6 Apr., 75
Sample
No.
27
14
27
14
14
14
14
14
Max.
142
17.9
863
226
18.8
0.55
57.9
40,000
Mean
57.0
10.9
423.3
92.5
7.27
0.29
16.0
-
Min.
11.3
5.9
10.4
4.0
3.75
0.05
2.1
370
Summary
Mean
54.7
8.4
344.6
99.9
7.4
0.48
16.9
-
Range
980 ~ 9.5
70-2.2
2,561-6.3
1,360-1.0
71-0.6
2.96-0.05
538-0.1
500,000-2
*: Kiehldahl  * *: Soxhlet method
                                          407

-------
                                     Table 9   Quality of Urban Stormwater (2)

                                               (Midorichyo, Yamagata)

BOD
S-BOD
SS
VSS
T-N*
T-P
Grease**
Total
MPN
19 Sep., 74
Sample
No.
48
24
48
24
24
24
24
24
Max.
20.3
8.7
103.0
47.5
3.9
0.6
13.0
64,000
Mean
6.90
3.61
37.6
19.0
0.87
0.18
8.50
-
Min.
3.1
1.8
8.3
3.6
N.D
0.09
4.3
1,100
15 Oct., 74
Sample
No.
30
15
30
15
15
15
15
15
Max.
55.4
35.6
131.0
76.5
11.2
1.67
11.8
120,000
Mean
45.7
11.4
79.6
23.4
3.42
0.77
7.75
-
Min.
24.2
12.2
59.5
39.0
1.8
0.42
5.4
600
22 No., 74
Sample
No.
48
24
48
24
24
24
24
24
Max.
70.4
50.3
175.7
116.7
0.3
0.57
15.9
9,200
Mean
35.8
10.0
93.9
33.3
0.08
0.19
8.95
-
Min.
18.3
8.9
27.7
28.2
N.D
0.06
4.1
220
14 Dec., 74
Sample
No.
18
9
18
9
9
9
9
9
Max.
60.7
52.4
279
20.7
0.3
0.29
23.7
610
Mean
39.8
15.3
246.7
8.72
0.12
0.18
19.2
-
Min.
25.0
21.0
222
11.9
N.D
0.12
15.2
210
Summary
Mean
32.0
10.1
114.5
21.1
1.12
0.33
11.1
-
Range
70.4 -3.1
52.4-1.8
279-8.3
117~11.9
11.2-N.D
1.67-0.06
23.7-4.1
120,000-210
o
OO
            *: Kjehldahl  **: Soxhlet method

-------
                                                          Table 10   Quality of Urban Stormwater (3)

                                                                    (Shimizugawa, Gifu)
^^^
^\
BOD (mg/e)
SS (mg/£)
VSS (mg/£)
^\^^_
^\
BOD (mg/2)
SS (mg/£)
VSS (mg/£)
6 July., 67
Samples
40
40
40
Max.
14.3
268.0
116.0
Mean
11.6
145.0
75.0
Min.
3.83
18.0
10.0
19 July., 67(1)
Samples
44
44
44
Max.
14.2
476.0
110.0
Mean
8.7
251.8
62.0
Min.
4.03
46.0
24.0
12 July., 67(1)
Sample
82
82
-
Max.
13.1
78.0
-
Mean
7.3
43.0
-
Min.
3.2
30.0
-
19 July. ,67(2)
Sample
34
34
-
Max.
10.7
88.0
-
Mean
6.8
45.2
-
Min.
5.04
13.4
-
12 July. ,67 (2)
Sample
65
65
-
Max.
11.3
162.0
-
Mean
7.3
71.0
-
Min.
4.11
9.0
-
22 Aug., 67
Sample
85
85
-
Max.
13.9
208.0
-
Mean
7.2
113.0
-
Min.
3.43
57.5
-
\
Summary
Mean
8.15
111.5
68.5
Range
3.2-14.3
9.0-476.0
10.0-116.0
o
to

-------
Table 11   Comparison of Quality (Strength) of Storm Water Discharges
City
Ann Arbor, Michigan
Des Moines, Iowa
Durham, N.C.
Los Angeles, Calif.
Madison, Wisconsin
New Orleans, La.
Sacramento, Calif.
Tulsa, Oklahoma
Washington, B.C.
Hanakuma, Kobe
Midoricho, Yamagata
Shimizugawa, Gifu
BOD5
Ave.
28
36
32
9.4
—
12
106
11
19
55
32
8
COD
Ave.
—
-
224
-
—
—
58
85
335
_
-
-
SS
Ave.
2,080
505
-
1,013
81
26
71
247
1,697
345
279
112
Total
MPN/100 mfi
—
—
3 x 10s
-
—
1 x 106
8.10s
1 x 10s
6xl05



                                410  -

-------
Table 12   Estimated Annual Load of Pollutants from Urban Land
Pollutant
Flow (103 m3/year)
BOD (t/year)
SS (t/year)
TKN (t/year)
Seconda
effluen
145,990
2,845
3,712
2,801
ry
t
%
92.6
73.1
67.1
95.4
Prima
efflue
2,205
267
306
58
ry
nt
%
1.4
6.9
5.5
2.0
Combinec
overfl
9,486
111
1,518
78
sewer
3W
%
6.0
20.0
27.4
2.6
                            411

-------
-pi
I—1
oo
                Q

               m3/S



                 SOH
BOD, SS

 mg/C
                    k 600
                 40-\
500
                    Uoo
                 30H
                    -300
                 20H
                    \-200
                    uoo
12:00
                                  13:00
                                                14:00
                                                                                                    '	0

                                                                                                    o—oSS

                                                                                                    A—ABOD
                                                                15:00
                                                           16:00          17:00


                                                        Time


                    Fig. 1  Relationship BOD, SS to Rainfall (1 March 73, Yabatagawa, Tokyo)
                                                                                         18:00
                                                                                                                0 mm/h




                                                                                                                10



                                                                                                                20



                                                                                                                30
19:00
                                                                                                                                           20:00

-------
-pi
I—1
01
                   m3/S
                         U700
                      50-
                         -600
                      40--500
                      30-
                      10-
BOD, SS
rng/2
                         -400
                         -200
                          -100
                            13:00
                                           14:00
                                                                                Q
                                                                               . BOD
                                                                               )SS
                                                                                                      18:00
                                 15:00          16:00           17:00
                                                       Time

                        Fig. 2   Relationship BOD, SS to Rainfall (25 Aug. 73, Yabatagawa Tokyo)
                                                                                                                     19:00
0 mm/h

10

20

30
                                                                                                                                    20:00

-------
-Pi
            20
            10 -
                   5:00
6:00         7:00
                                                            5:00
                                         9:00           10:00



                                               Time
                                                                                                     11:00         12:00
                                                                                                                                 13:00        14:00
                                                  f\Q. 3  Relationship BOD, SS to Rainfall (10 Nov. 73, Yabatagawa, Tokyo)

-------
1000-
                                         BOD load (g/sec)
                                         BOD cone. (mg/C)
                                         Flow rate (m3/sec)
            6:00
                        7:00
8:00         9:00

      Time
                                                        10:00
                                                                    11:00
                                                                              12:00
                                                                                          13:00
                                                                                                    14:00
            \9. 4   Variation of BOD Load & BOD Concentration (10 Nov.  73,  Yabatagawa, Tokyo)

-------
   10:00
                                                                                                         m3/sec)
                                                                                                         0.06
                                                                                                         0.05
                                                                                                         0.04
                                                                                                        -0.03
                                                                                                         0.02
                                                                                                         0.01
                                                                                                 13:30
                                             Time
Fig. 5   Heavy Metals Contained  in Urban Stormwater (22, Nov. 1974, Midorichyo, Yamagata)

-------
Ul
Lo
131 K
321
626
3perBOD|
werSS J
255 S
L190
371
Primary
Treat-
ment
, 161
201 *^>

Secondary
Treat-
ment
^
1 I 38
\S 47

\
BOD
SS
Re-
moval
70l
173
Effi-
ciency
22%
28

Fig. 6  Annual Load of Pollutants from Combined Sewer Overflows,
       Yabatagawa, Tokyo. .      (t/Y)
Up
Lo
K
321
626
t/y
per BOD
werSS
321
626

321
626


124 \
242 /
/
197
384 K

K

124 \
242 /
197
384

V
K

124 \
242 /
V
197
384
	 N
>


Secondary
Treatment
TT82
1 I161
Storage Tank

Secondary
Treatment
n
Storage Tank

Secondary
Treatment
f>H3
I | 280
Storage Tank

45
68 h
>
91
123 K
	 ,>
54
81

57
59 K
>
59
88 N
k>
37
31 K
>
27,000m3
"\
BOD
SS
Re-
moval
1851
435
Effi-
ciency
58%
69
54,000 m3
^\
BOD
SS
Re-
moval
2101
486
Effi-
ciency
65%
78
81,000m3
\^
BOD
SS
Re-
moval
225*
507
Effi-
ciency
70%
81
V
    Fig. 7  Estimated Effect of Storage Tank, Yabatagawa Tokyo
                             417

-------
                              Fourth'US/JAPAN Conference
                                       on
                              Sewage Treatment Technology
                                    Paper No. 8
CASE  STUDIES  OF  INDUSTRIAL WASTEWATER
                   TREATMENT
                  October 29, 1975
                  Washington, D. C.
               Ministry of Construction
                Japanese Government
                        418

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       CASE STUDIES OF INDUSTRIAL WASTEWATER TREATMENT
1.   Material Balance of Heavy Metals in Sewage Treatment Process	420
       Mr. Ken Murakami, Chief, Water Quality Section,  Water Quality Control
       Division, Public Works Research Institute, Ministry of Construction
2.   Torihama Industrial Wastewater Pretreatment Plant in Yokohama
     — Operation and Maintenance —	45]
       Mr. Masayuki Sato, Director, Sewage Works Bureau, City of Yokohama'
3.   Fukashiba Industrial Wastewater Treatment Plant in Ibaragi Prefecture . . . .466
       Mr. Satoru Tohyama, Head, Sewage Works Division, Department of
       Sewarage & Sewage Purification, Ministry of Construction
4.   Design and Operation of Dying Waste Treatment Facility in Sabae City,
     Fukui Prefecture	477
       Dr. Mamoru Kashiwaya, Head,  Water Quality Control Division, Public Works
       Research Institute, Ministry of Construction
5.   Improvement of Effluent Quality of Bisai District Sewage Treatment Plant
     in Aichi Prefecture	489
       Dr. Mamoru Kashiwaya, Head,  Water Quality Control Division, Public
       Works Research Institute, Ministry of Construction
                                       419

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CHAPTER 1.  MATERIAL  BALANCES OF  HEAVY  METALS IN SEWAGE
              TREATMENT PLANTS
1.1  Effects of Cadmium, Lead and Mercury on the Biological Treatment
    Process  .       	      	421
  1.1.1   Effects of Cadmium on the Biological Treatment	421
  1.1.2   Effects of Lead on the Biological Treatment	422
  1.1.3   Effects of Mercury on the Biological Treatment	  423
  1.1.4   Summary  	       	424
1.2  Influent Heavy Metal Concentration and Its Loading Balance in the Sewage
    Treatment Plants	425
  1.2.1   Sewage Treatment Plants Surveyed and Outline of Survey	425
  1.2.2   Results and Discussion	426
  1.2.3   Summary     	427
                                   420

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1.   MATERIAL  BALANCES  OF  HEAVY  METALS  IN  SEWAGE  TREAT-
     MENT  PLANTS
1.1  EFFECTS OF CADMIUM, LEAD, AND MERCURY ON THE BIOLOGICAL
     TREATMENT PROCESS
     The Public Works Research Institute, Ministry of Construction has, during the
past three years or so,  conducted experiments  using bench scale activated sludge
apparatus to clasify effects of cadmium, lead, and mercury, on biological treatment
process and material balance of heavy metals in the process.
     The laboratory apparatus used is shown in Fig. 1.1. The apparatus was modified
so that it can collect vaporized mercury when experimenting on mercury.
     Table 1.1 shows the design data and loading factors of the experiments. Sewage
used in the experiments is synthetic sewage and ingredients are shown in Table 1.2.
Cadmium, lead, and mercury were added to sewage in the  forms of cadmium sulfate,
lead nitrate, and mercuric chloride, respectively.
     The acclimatization period was taken about two weeks from the day the heavy
metal addition was started.
1.1.1   EFFECTS  OF  CADMIUM ON THE  BIOLOGICAL TREATMENT
i)    Experiments was made at each of three levels of cadmium in the influent feed,
     0.1, 1.0, and 10mg/l.
ii)   Average effluent quality obtained are shown in Table 1.3. In the case of influ-
     ent  with the cadmium  concentration of 1 mg/1, no influence appeared on  the
     effluent. But one containing 10 mg/1 of cadmium experienced lowering of the
     transparency of the effluent and  increase in SS and BOD. As for soluble BOD,
     no  significant differences have  been seen during  all the  experiments, but
     insoluble  BOD in the effluent increased as cadmium concentration of sewage
     become higher.
     From the relations between heavy metal content in  activated sludge and those
     in SS of the effluent, which are shown in Table 1.4,  it was conjectured that SS
     of the effluent is composed of organisms lighter than activated sludge, or their
     debris.
     In the case of influent  containing 1 mg/1 of cadmium, cadmium concentration
     of the effluent was approximately 0.3 mg/1.  Cadmium in the effluent was most-
     ly a insoluble.
iii)   Characteristics of activated sludge are shown in Table 1.5.
     Relations between cadmium concentration in sewage sludge production and
     oxydation rate of sludge are shown in Fig. 1.2.
     Transfer rate of removed  BOD into sludge was about 0.5 when cadmium con-
     centration was 1 mg/1, and about 0.7 when  the concentration  was  10 mg/1.
     These results may indicate that when heavy metals exist in sewage, excess ac-
     tivated sludge will increase.
     Existence of cadmium  in sewage has changed the  fauna  in activated sludge:
     protozoa died out and it became composed mostly of bacteria.
     When cadmium concentration  in the culture medium by batch  culture is less
                                    421  -

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    than  10 mg/1, the growth rate  of bacteria separated  from activated sludge
    showed no significant difference against the control.
iv)  Fig. 1.3 shows relations between cadmium content in activated sludge and cad-
    mium  concentration in the influent. This Figure clearly shows that cadmium
    content in activated  sludge varies depending on cadmium concentration in the
    influent.
    In  10 or so days after cadmium addition was started cadmium concentration in
    sludge became almost constant.
    "Concentration factors" were approximately 28 x 103 when influent cadmium
    concentration was 0.1  mg/1 and  1.0 mg/1, and 9 x 103 when it was 10 mg/1.
    These  results were similar to those obtained in surveys at sewage treatment
    plants.
v)  Table 1.6 shows the material loading balance of cadmium in the process. "Unac-
    counted for" in this Table is a  value subtracted cadmium in effluent and in-
    excess activated sludge from that in influent. It is considered that this "unac-
    counted for" includes  errors due to sampling of MLSS for analysis and those in
    measuring growth of  activated sludge. In experiments on sewage  containing
     10 mg/1 cadmium, pink-yellowish substance like cadmium sulfide was perceived
    on the wall  of the aeration tank. This substance is  also considered to be in-
    cluded in "unaccounted for."
    Assuming that the "unaccounted for" flowed out as excess sludge, over 80% of
    it is considered  to transfer into the sludge treatment process, when cadmium
    concentration is less than 1 mg/1.
    As influent cadmium concentration increases, percentage of cadmium existing
    in effluent as insoluble form becomes higher. In the case of 1 mg/1 of cadmium,
    about  80% of cadmium flowing out together with effluent was insoluble.
1.1.2   EFFECTS OF LEAD ON THE  BIOLOGICAL  TREATMENT
i)  Experiments was made at each of five levels of lead in the influent feed, 0.1,
    0.25, 1.2, 7.9, and 95.5 mg/1.
ii)  Average effluent quality obtained are shown in Table 1.7. When lead  concentra-
    tion in influent was 1 mg/1, no influence  appeared on the effluent. When the
    concentration was 8 mg/1,  transparency  of effluent  became lower  and the
    quantity  of SS  and insoluble BOD increased. Significant differences in the
    soluble organic constituents in effluent were hardly perceived in each run.
    From Table  1.4, it has been found that SS in effluent was due to the washout
    of activated sludge.
    Effects of lead on the  biological treatment appeared when  its concentration in
    influent exceeds 8 mg/1. Symptom is a washout of activated sludge.
iii)  Characteristics of activated sludge^are shown in Table 1.8.
    As in the  case  of cadmium, sludge production  tended  to increase  by the
    addition of lead.
    In the case of transfer rate of removed BOD into sludge, the results were similar
    to  those in experiments with cadmium. When lead concentration  in influent
                                  -  422 -

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     was less than 8 mg/1, transfer rate of removed BOD into sludge was 0.3 to 0.4.
     As  for fauna in  activated sludge, when influent  contained  8 mg/1  of lead,
     Volticella, Epistylis and Charchesium  were perceived in a small  quantity.
     Toxicity  of lead  was examined by shaking culture  using activated sludge in
     which protozoa does not exist. As a result, when the concentration of lead was
     less than 100  mg/1, the activity of activated sludge deteriorated temporarily.
     But the recovery  rate of activity of  activated sludge was at the same level of
     that of control.
iv)   Fig. 1.3 shows relations between content of lead in activated  sludge and lead
     concentration in the influent.
     In about a week after lead was added to the influent, the lead concentration in
     activated sludge became a constant thus reaching a steady state.
     The concentration factor was 8.8 to  11.1  x 103 when lead in influent was less
     than 8 mg/1.
     Because lead tends to produce insoluble compounds when mixed with influent,
     it is considered that the state of lead in sludge is different  from that of other
     elements.
v)   Table  1.6 shows the material loading balance  of lead in the  process.  "Unac-
     counted for" was  similarly treated  as with the  case of cadmium. The quantity
     of lead transferring into the sludge treatment process tended to increase as the
     lead concentration in influent increased.
     When the lead concentration in influent was less than 1 mg/1, 30 to 50% of lead
     in effluent was discharged as  insoluble form. And when the concentration was
     8 mg/1, over 90% of lead flowed out was insoluble.
1.1.3  EFFECTS OF  MERCURY ON THE BIOLOGICAL TREATMENT
i)    Experiments was made at each of three levels of mercury in the influent feed,
     4, 100 and 1,000 mg/1.
ii)   Average effluent quality obtained  are shown  in Table 1.9. When mercury in
     effluent was 4 /ug/1,  SS, COD, etc. of effluent increased and  transparency de-
     creased.
     As in the case of cadmium, SS in effluent is considered as organisms lighter than
     activated sludge or their debris (Table  1.4).
     It seems that effects  of mercury on the biological treatment are observed when
     the mercury in influent exceeds 4 jug/1.
Hi)   Table 1.10 shows  characteristics of activated sludge. Sludge  production showed
     the same tendencies as with cadmium  and lead.
     Transfer rate of removed BOD into sludge was 0.4 when mercury in influent
     was 4 jug/1  and about 0.5 when it was 1 mg/1. The same rate of control was
  .   about 0.3.
     When mercury in influent was less  than 4 jug/1,  protozoa was perceived in
     activated sludge. But when the mercury concentration was lOO^g/1, bacteria
     similar to zoogloea were dominant.
iv)   In the  biological  treatment,  when  mercury in influent was about 1 mg/1, the
                                     423

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     amount of vaporized mercury was aproximately 17 /ug/day/g.SS. In other runs
     with mercury, quantitative analysis of vaporized mercury was impossible.
     State of vaporization of mercury in aeration tanks is shown Fig. 1.4. As clearly
     shown in the Figure, it has been found that most of mercury to be vaporized in
     aeration tanks is vaporized at the first quarter of the path of the tanks.
v)   Relations between mercury content in activated sludge and mercury concentra-
     tion in influent are shown in Fig. 1.3.
     As a result of measurement by a gaschromatograph whose sensitivity is 0.01 mg
     alkyl-mercury/kg.SS alkyl-mercury was not detected in activated sludge.
     Concentration factor was 42 x 103 when mercury in influent was about 4 jug/1.
vi)   Table 1.6 shows material loading balance of mercury in the process.
     Unlike in the cases of cadmium and lead, when mercury in influent was about
     4 jug/1, the total of mercury discharged as effluent and vaporized mercury was
     some 10%. Therefore, mercury is easily accumulated in sludge.
     Around  50% of effluent mercury was insoluble.

1.1.4  SUMMARY
1)   When cadmium, lead, or mercury is contained in sewage, the minimum concen-
     tration of them which  gives effects on the biological treatment is as follows:
       Cadmium             1  to 10 mg/1
       Lead        approx.   10 mg/1
       Mercury    approx.   5 jug/1
     Actual effects of these heavy metals  on the biological treatment appeared in the
     form of decrease in transparency of effluent and increase in SS.
     Within the above-mentioned  level of heavy metal concentration, there were vir-
     tually no effect of them on removal  of organic matters.
2)   In cases of cadmium and mercury, SS in effluent showed those characters which
     no protozoa existed in activated sludge. In the case of lead, SS in effluent was
     due to the washout of activated sludge.
3)   By the addition of heavy  metals, the fauna of activated sludge was changed:
     while protozoa decreased in number, bacteria became dominant species.
     Within  ranges of concentration of heavy metals in the present experiments,
     growth rate  of bacteria separated from activated sludge was hardly affected.
4)   Heavy metals in influent tended to accelerate sludge production. This is con-
     sidered, from 3)  above, to be caused  by the difference in food  chain  of
     organism in activated sludge.
5)   Accumulation of heavy metals  on activated sludge depends upon their concen-
     tration in influent.
6)   Concentration factor of the heavy metals was around 104. Most of heavy metals
     contained in influent is transferred to the sludge treatment process.
7)   Outline  of effects of each element on the biological treatment process is shown
     in Table 1.11.
                                     424

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 1.2 INFLUENT  HEAVY  METAL  CONCENTRATION  AND  ITS  LOADING
     BALANCE  IN  THE SEWAGE  TREATMENT PLANTS

     In Japan,  the concern in the effects of heavy metals in the sewage upon the
 activated  sludge  process is veering round toward the  extent to which the heavy
 metals, though  little  in quantity, in the sewage are entrained into the sludge through
 the biological treatment process, rather than toward the interference with the biolo-
 gical treatment  itself.
     This is because as the environmental standards and pretreatment facilities ef-
 fluent standards have been established it is almost unlikely so far as municipal sew-
 age treatment plants are concerned that heavy metals will run into them at as high
 concentrations  as to interfere biological treatment.
     On the  other hand, it is noticed that even if heavy metals in the influent is a
 trace level, they  can  accumulate  to  amass their  concentrations in the sludge. This
 fact urges the collection of information about the relationship between the concen-
 trations of heavy  metals in the influent sewage and those in the sludge.
     Dealt with here are the concentrations of heavy metals contained in domestic
 sewage, concentrations of heavy metals accumulated in sludge and heavy metal bal-
 ance in the sewage treatment  plant which  are discussed  based  on the results of
 survey  on the  sewage treatment  plants treating  domestic sewage alone and those
 taking in industrial effluents combined with domestic sewage.

 1.2.1   SEWAGE TREATMENT PLANTS SURVEYED AND OUTLINE OF SUR-
        VEY
     A field survey was conducted from July 1973  to September 1974. The sewage
 treatment plants  surveyed included two domestic sewage  treatment plants located
 near residential  areas and two comparatively large municipal waste treatment plants.
     The latter  two were picked up as  typical of those treating municipal sewage and
 not as special problem solvers of industrial  wast water.
     These four sewage treatment plants are outlined in Table 2.1.
     Plant "A" is a medium-sized one which is  estimated to have  been receiving
 some 8,000 m3 /d  from industries suspected to discharge heavy metals out of its total
 daily processing rate of 50,000 m3.
     Plant "B"  comes under the catagory  of large-scale plants. It has been treating
 400,000 m3 /d of which some 200,000 m3 /d are accounted for by industrial waste-
 water, and is estimated to have been receiving at least about 2,000 m3 /d from indus-
 tries likely to discharge heavy metals.
     Plants "C" and "D" are small-scale ones in the residential areas which are not
 receiving industrial wastes at all.
     All these plants are undertaking  the conventional activated sludge process after
 primary treatment. The flow diagram is all  the same.
     Plants "A" and "D" have their sludge  treated  at nearby sludge treatment plants.
Plants "B" and  "C" are practising anaerobic digestion of sludge, and the supernatant
 to be developed in the sludge treatment process is returned to the head of the pri-
mary settler.
                                  - 425 -

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     The survey was conducted with one day as a unit. The sampling was conducted
for 24 consecutive hours; some samples were gathered into a composite one, and
some others were handled as grab samples.

1.2.2  RESULTS AND DISCUSSION
Concentrations of heavy metals in domestic sewage
     Table  2.2 shows the mean values and range of concentrations of heavy metals
in the domestic sewage obtained at plants "C" and "D".
     Copper,  chromium,  cadmium, lead, nickel, zinc and mercury were  measured.
As shown in Table 2.2, all these seven heavy metals were detected.
     The concentration of zinc was the highest with the order of 10~2 to 10"1, fol-
lowed by copper with 10~2, chromium, nickel and lead with 10"3 to 10~2, cadmium
with 10"3 and mercury with 10"4, all in terms of mg/lit.
     From  what these heavy  metals come is  still  unknown, but foods, plumbings,
kitchen utensils and the  like  are suspected. It is  also reported that cadmium and
mercury are deeply concerned with foods.
Accumulation of heavy metals in sludge
     Primary sludge and waste activated sludge sampled from each plant were meas-
ured for heavy metals.
     Figs. 2.1  and 2.2 show the relationships  between the concentrations of heavy
metals in the  influent sewage and those in the primary sludge and waste activated
sludge.
     For both, daily average values are taken.  It is evident from the figures that the
concentrations in the influent have a great bearing on the concentrations in the pri-
mary sludge and waste activated sludge. The  straight lines appearing in the  figures
show the multiples (accumulation coefficients) of the concentrations in influent and
sludge.
     The concentrations of heavy metals in the influent sewage were as small as less
than 1 mg/lit., and the laboratory test results explained in Chap. 1, and the results of
field survey and laboratory tests conducted by Taft Center, U.S.A. are annexed in
order to corroborate the above findlings. (See Figs.  2.3 and 2.4.)
     As a result, there are found the interesting facts as follows.
1)   In the case of primary sludge, when the concentrations of heavy metals in the
     influent sewage exceed 10 mg/lit., the relationship between the concentrations
     in the influent and those in the sludge loses linearity, with the result that the
     concentrations in the sludge become in a specified range (1 to 10 mg/SSg)
2)   In the case of waste activated  sludge, even when  the concentrations in  the in-
     fluent sewage go up to 100 mg/lit., it does not matter to  the linearity; namely,
     the concentrations of heavy metals  in the waste activated sludge increase on
     and on.

     Considering these  and other various factors,  the  following may be said about
the accumulation of heavy metals in the sludge in the sewage treatment plant.
1)   At sewage treatment plants operated under ordinary conditions, the concentra-
                                      426

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     tions of heavy metals in the sludge are closely related with those in the influent
     sewage, though dependent on the kinds of heavy metals.
2)   The multiples (accumulation coefficients) lie in the range of 103  to 104, and
     104 should be taken up if safety factor is considered.
3)   In  the case of primary  sludge, the linear relationship between the concentra-
     tions of heavy metals in the influent sewage and those in the sludge is lost when
     the former exceeds 10 mg/lit., and thus the  concentrations of heavy metals in
     the sludge remain within the range of 1 to 10 mg/ssg.
4)   The field surveys at sewage treatment plants could not clarify the difference in
     accumulation rate between metals.
5)   The sludge delivered from  the sewage  treatment plants processing domestic
     sewage alone also concentrate heavy metals.  According to the measurements at
     plants "C" and "D", the heavy metals are estimated to have been concentrated
     to the levels given below.
     Copper:  100 ~  1,000 mg/kg; zinc: 100 ~ 10,000 mg/kg; chronium, nickel &
     lead: 10 ~ 1,000 mg/kg; cadmium: 10 ~ 100 mg/kg; mercury: 1 ~ 10 mg/kg.
Heavy metals balance  in the sewage treatment plant
     As regards plant "B" where supernatant is sent back to the head of the primary
settler from the sludge treatment system, the results of heavy metals balance between
facilities are shown in Table 2.3.
     The figures are all based on actual observation. The run-in and run-off values of
each facility are given with the total amount of heavy metals in the influent sewage
taken as 100.
     Namely, run-in and run-off amounts of each  facility are divided by the amount
in the influent sewage. The following are found by twice surveys.
1)   Nickel and cadmium are liable to remain in  the effluent. As regards cadmium,
     this tendency is considered attributable to  its relatively low concentration in
     the influent sewage.
2)   The amount of heavy metals conveyed by recycled waste such as supernatant of
     anaerobic digester is by far the more  larger than that in the influent sewage; in
     some cases, it becomes 4 times as large.
3)   Almost all of heavy metals contained in the recycled waste are insoluble.
4)   Accordingly, they are settled easily in the primary settler, and are recycled be-
     tween the sludge treatment system and sewage treatment system. The concen-
     trations of heavy metals in the influent sewage become almost equal to those in
     the primary effluent.

1.2.3  SUMMARY
1)   Domestic sewage contains heavy metals, whose concentrations are found to be
     in certain ranges.
2)   It is disclosed that the  accumulation of heavy metals in the sludge is closely
     related to the concentrations of heavy  metals in the influent sewage.
                                    427

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3)  The accumulation coefficient is in the  order of some 104  irrespective of the
    kinds of heavy metals, and when the concentrations in the influent sewage are
    once clarified, the concentrations in the sludge can therefore be estimated.
4)  An actual example of material balance concerning heavy metals in the sewage
    treatment plant is given.
                                    428

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     Table 1.1   Design Data and Loading Factor (Bench scale activated
                 sludge apparatus)

                       Apparatus design data and loading factors
Aeration tank
     Capacity
     Aeration period
     Return sludge rate
     BOD loading
    00
    (%)
(kg/day/kg, ss)
 60
  4
 25
0.3
Final settler
     Capacity
     Detention time
     Surface overflow rate
    00
(//day/cm2)
 24
 1.6
0.87
                                      429

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Table 1.2  Composition of Synthetic Sewage  (mS/0
Substrate
Glucose
Dextrin
Meat extract
Peptone
Yeast extract
Concentration
17.6
17.6
80.0
80.0
90.0
Substrate
Urea
KC/
NaC/
MgS04
KH2 PH4
Concentration
37.0
8.1
8.1
5.4
24.5
                           BOD = 180mg//

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                               Table 1.3   Average Characteristics of Effluents for Control and Cadmium-fed Apparatus      S: Soluble matter
o-i
No.
(Cd in influent)
'A
(0 mg/fi)
B
(0.1)
c
(1.0)
D
(12.4)
Trans.
30<
13— 30<
11~30<
21
15~25
PH
5.8~6.9
5.6~6.6
5.6-7.0
6.8-7.3
SS
(mg/2)
36.3
16~104
50.7
2-140
51.0
10 — 108
82.4
34—144
B(
(mg/£)
8.68
6.96
6.94
12 A
)D
S(mg/£)
0.96
1.09
0.57
0.99
Percent removal
94.2
95.2
95.2
91.4
Cd
(mg/£)
-
0.022
0.30
6.91
S(mg/£)
-
0.013
0.049
1.04
Percent removal
-
80.0
71.1
44.2

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      Table 1.4   Metal Content in Activated Sludge and SS of Effluent
Metal
Cd
Pb
Hg
No. (Metal in influent)
A (0 mg/2)
B (0.11)
C (1.04)
D (12.4)
A (0)
B (0.1)
C (0.25)
D (1.2)
E (7.9)
F (95.5)
A (0)
B (0.004)
C (0.974)
Content of metal in sludge (mg/g. ss)
Aa
-
3.08
29.6
113
-
0.99
2.23
13.3
61.6
534
-
0.187
13.2
Ab
-
0.2
4.9
71.2
-
0.85
1.95
12.7
256
378
—
0.022
0.082
Aa/Ab
-%
6.5
16.6
62.8
-
85.9
87.4
95.6
-
70.8
-
11.8
0.6
Aa:  Metal content in activated sludge,  Ab: Metal content in SS of effluent

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Table 1.5  Effect of Cadmium on Activated Sludge
No.
(Cd in influent, mg/£)
A (0)
B (0.1)
C (1.0)
D (12.4)
MLSS
(mg/£)
3,814
2,818
2,957
2,702
MLVSS
(mg/£)
3,443
2,519
2,567
2,294
MLVSS
/MLSS
0.90
0.89
0.87
0.85
SVI
214
289
239
283
BOD 'loading
(kg/day/kg, ss)
0.23
0.31
0.30
0.32
Cd loading
(mg/day/g. ss)
-
0.17
2.1
27.5
Sludge production rate (g/day)
as SS
19.4
24.6
27.9
38.7
as VS
17.5
21.9
24.3
32.9
Content of Cd in
sludge (mg/g. ss)
-
3.08
29.6
113
Concentration
factor
-
28 x 103
28 x 103
9xl03

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Table 1.6   Balance of Metals  in Activated Sludge Process

Metal


Cd



Pb



Hg

No.

(Concentration in influent)
B (0.1 mg/0'
C (1)
D (10)
B (0.1)
C (0.25)
D (1.2)
E (7.9)
F (95.5)
B (4.4 PMg/2)
C (119)
D (974)
Material balance (%)

Effluent
20.1
28.8
55.8
55.6
27.3
32.6
81.7
10.6
5.27
1.57
0.34

Vapor
—
-
-
—
-
-
-
-
4.11
1.27
0.31

Excess activated sludge
51.3
78.3
23.1
22.2
41.5
29.1
19.8
44.7
62.3
83.6
89.0

Unaccounted for
28.6
—
21.1
22.2
31.2
38.3
—
44.7
28.3
13.6
10.4

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Table 1.7  Average Characteristics of Effeuents for Control and  Lead-fed Apparatus
No.
(Pb in influent)
A -(0 mg/fi)
B (0.1)
C (0.25)
D (1.2)
E (7.9)
F (95.5)
Trans.
29.6
30 <
30 <
30 <
26.1
20.0
PH
6.9
7.0
7.3
7.0
6.4
6.7
SS
(mg/£)
7.60
21.2
12.8
14.2
23.2
25.7
B(
(mg/£)
7.05
12.26
8.04
8.10
15.25
(5.16)
DD
S(mg/£)
2.21
1.73
1.49
1.68
1.50
(1.32)
Percent removal
95.3
91.5
94.6
94.5
88.7
(96.4)
C(
(mg/£)
9.22
11.83
7.27
7.31
9.92
7.60
DD
S(mg/£)
6.17
7.12
5.62
5.71
5.55
4.82
Percent removal
86.2
73.9
84.6
88.2
84.6
87.2
PI
(mg/£)
-
0.056
0.070
0.39
6.47
10.08
3
S (mg/fi)
-
0.038
0.045
0.21
0.54
0,36
Percent removal
-
43.6
29.7
67.5
18.3
89.4

-------
                                                         Table 1.8   Effect of  Lead on Activated Sludge
No.
(Pb in influent, mg/£)
A (0)
B (0.1)
C (0.25)
D (1.2)
E (7.9)
F (95.5)
MLSS
(mg/£)
2,419
2,263
2,280
1,474
1,751
12,860
MLVSS
(mg/£)
2,201
1,969
1,987
1,340
1,384
3,342
MLVSS
/MLSS
0.91
0.87
0.87
0.91
0.80
0.27
SVI
318
90
95
480
123
30
BOD loading
(kg/day/kg, ss)
0.64
0.40
0.40
0.59
0.56
0.08
•Pb loading
(mg/day/g. ss)
-
0.273
0.700
5.90
308
476
Sludge production rate (g/day)
as SS
9.4
14.9
21.2
14.4
17.3
22.0
as VS
8.5
13.0
18.5
13.1
13.9
6.0
Content of Pb in
sludge (mg/g. ss)
-
0.99
2.23
13.28
61.6
534
Concentration
factor
-
9.8 xlO3
8.8 x 103
11.1 xlO3
9.8 x 103
5.6 x 103
-fa.
O-l

-------
Table 1.9  Average Characteristics of Effluents for Control and Mercury-fed Apparatus
No.
(Hg in influent)
A
(0 Mg/£)
B
(4.4)
C
(974)
A'
(0)
D
(119)
Trans.
30
21.3
20.3
30
30
PH
7.0
7.3
7.3
7.0
7.0
SS
(mg/£)
3.5
25.5
20.0
-
-
B<
(mg/£)
4.42
8.13
18.40
4.55
4.57
3D
S(mg/£)
0.98
2.05
3.66
0.79
0.70
Percent removal
96.8
93.9
85.6
95.3
95.3
CC
'(mg/£)
6.43
12.30
18.50
8.68
18.33
)D
S(mg/£)
4.97
5.71
7.85
7.81
9.11
Percent removal
88.9
79.2
67.7
87.0
63.4
H
(Mg/£)
-
0.97
3.35
-
1.87
g
S(Mg/£)
-
0.41
1.72
-
1.34
Percent removal
-
78.3
99.7
-
98.4

-------
                                                      Table 1.10   Effect of Mercury on  Activated Sludge
No.
(Hg in influent, Mg/£)
A (0)
B (44)
C (974)
A' (0)
D (119)
MLSS
(mg/g)
1,351
1,676
1,065
2,077
1,437
MLVSS
(mg/£)
1,174
1,473
956
1,830
1,236
MLVSS
/MLSS
0.87
0.88
0.90
0.88
0.86
SVI
644
482
688
421
324
BOD loading
(kg/ day/kg, ss)
0.57
0.47
0.75
0.21
0.24
Mercury loading
(Mg/day/g. ss)
-
15.98
5,490
-
410
Sludge production rate (g/day)
as SS
15.9
31.4
30.8
10.3
12.5
as VS
13.8
27.6
27.7
9.1
10.8
Content of Hg in
sludge (Mg/ss. g)
3.22
187
1.34 x 104
3.05
2.87 x 103
Concentration
factor
-
42 x 103
14xl03
-
24 x 103
OO
 I

-------
                                     Table 1.11   Summary of the Result
Metal

Cd


Pb

Hg
Expected maximum
concentration in influent

0.1 rng/g


1.0

5 Mg/e
Highest dose of metal for satis-
factory biological treatment

1~10 mg/e
(5)

10

>5 Mg/£
Percent removal
BOD

95


95

94
Metal

80


70

80
Content of metal in
sludge (mg/ss. g)

3
Concentration
factor
(28 x 103)

13
(11 xlO3)

0.2
(42xl03)
Growth of
sludge
M d/day)
0.1455
Control
(0.0848)
1.72*
0.1629
(0.0644)
2.53*
0.3125
(0.1957)
1.60*
*:  Ratio against control

-------
Table 1.12  Outline of STP Surveyed
~~~ — — - — _____Name of STP
Item - — -—_ __
Area served (ha)
Population served
Daily average flow (m3/d)
Collection system
Secondary treatment system
Remarks
A
1,134
139,000
53,000
Combined sewer
Conventional
activated sludge

B
2,939
498,600
400,000
Combined
sewer
The same
as left

C
701
6,000
4,000
Separate
sewer
The same
as left
Domestic
sewage
D
748
46,000
20,000
Separate
sewer
The same
as left
Domestic
sewage
              440 -

-------
Table 1.13  Heavy Metal Concentration in Domestic Sewage
                                                            (mg/C)
\JHeavy metal
STP~"~^--^
D, Feb. '75
D, Mar. '75
D, Feb. '73
D, Nov. '73
C, Sept. '73
C, Mar. '73
Cu
0.029
0.029
0.046
0.031
0.029
0.016
Cr
0.001
0.000
0.018
0.000
0.023
0.032
Cd
0.0012
0.0029
0.0022
0.0016
0.0026
0.0031
Pb
0.0025
0.0013
0.020
0.016
0.038
0.028
Ni
0.009
0.000
0.055
0.001
0.019
0.015
Zn
0.13
0.12
0.295
0.156
0.055
0.054
Hg
-
-
0.0000
0.0001
0.0002
0.0005
Remarks
3 day
average
3 day
average
A day
composit
A day
composit
A day
composit
A day
composit
                       - 441 -

-------
                                      Table 1.14  Heavy Metal Loading Balance in Sewage Treatment Plant (Observed at B STP)
^~\^Heavy metal
Location ^^^^
1 Raw sewage
2 Superrnatant
Primary
Influent
Primary
Effluent
Final
Effluent
Concentration
in raw sewage
(mg/J2)
Cu
Total
100
100
478
16
519
129
103
90
13
17
Sol.
46
55
1
1
. 11
13
16
11
Insol.
54
45
477
15
508
90
74
2
17
0.137
0.111
Cr
Total
100
100
301
182
347
300
159
124
29
23
Sol.
85
48
1
3
41
37
46
32
29
Insol.
15
52
300
180
306
260
113
92
0
23
0.113
0.105
Cd
Total
100
100
423
175
253
233
219
144
294
67
Sol.
82
28
9
231
137
118
79

CO
           Notes: 1. Number indicates raw sewage values of 100 or proportional relationship based on it.


                 2. Above Aug. Survey, Beneath, Mar. Survey.



                ©
           Inf.
                                                                                                                                     Discharge
                        Supernatant
                                                Sludge Treatment Facilities

                                                (Thickner, Anaerobic Digester, Vacuum Filter and Incinerator)
                                                              Schematic Flow Diagram of the B STP

-------
Air
       r\
        M
                    r~\
                     M
       No.1          2
        Aeration Tank
             (7.5£x 8 tank)
                                                    I  :  Tap Water
                                                    II  :  Synthetic Sewage
                                                    III :  Solution of Metal
                                                   P)  :  Pump


V
-=•


V


                                                             Effluent
Final Settler
  (242)'
         Fig. 1.1   Bench Scale Activated Sludge Apparatus
                              -  443  -

-------
   40r
   30
   20
c
o
 3
•a
 o
£  10
 00
•a
                                                                                                X 1Q-7


                                                                                               ' -.9
         0

        ( Control )

                                                                                                      E
                                                                                                      CL,
                                                                                                      00
                                                                                                      T3
                                                                                                      J3

                                                                                                      to
              Di



              I
              'H
              T3
0.1
10
                                       Cd in Influent (mg/2)
         Fig. 1.2   Relationship Between Sludge Production and Oxidation Rate and Cd in Influent
                                                -  444  -

-------
I
 

8 o.oi
  0.001
            —°Sludge   ph
            —"Effluent n
            —o Sludge   rj
            —•Effluent ^
            —A Sludge   H
            —A Effluent Hg
      0.001      0.01       0.1         1

                  Metal in Influent (mg/fi)
                                                       100
10
                                                 10
                                                       0.1
                                                       0.01
                                                       0.001
                                                              c
                                                              
-------
>,
cd
•O

oo






3
O


&
     500
     400
     300-
     200-
     100-
       0 •
           Fig. 1.4  Vaporized Mercury in Each Aeration Tank
                           -  446  -

-------
10
so
n
?
I '
0
>-,
2
5 o.i
3
,>
3
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n nnni
























































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2. BSTP
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                0.01             0.1

                Influent Heavy Metal Concentration (mg/G)
Fig.  1.5   Relationship between Influent Heavy Metal Concentration
          and  Content in Primary Sludge
                         -  447  -

-------
"ontent in Activated Sludge (mg/SS.g)
o - 3
^ — 0 o
s.
>
I
0.01



























/



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/











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Cd
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:. B STP
3. C STP
4. D STP



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Fig. 1.6   Relationship between  Influent Heavy Metal Concentration
          and Content in Activated Sludge
                         -  448  -

-------
100
10
1
0.1
0.01

.001



1001




-



























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J Vcd
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fljT T
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ASTP
BSTP
CSTP
DSTP
Grand Rapids*
Richmond*)
Bryan*
In House (Tafl Center *)










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                              Influent Heavy Melal Concentration (nig/V)
*) After "Interaction of Heavy Metals and Biological Sewage Treatment Processes" U.S. PUS. No.999-WP-22. 1965.

          Fig.  1.7   Relationship between Influent  Heavy Metal Concentration
                     and  Content in Primary  Sludge
                                         449  -

-------
100
10
1
0.1
0.01





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2. BSTP
3. C STP
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              0.001            0.01              O.I               1                 10
                               Influent Heavy Metal Concentration (mg/P)
*)  Alter "Interaction of Heavy Metals and Biological Sewage Treatment Processes" U.S PHS, No999-WP-22. 1965.

          Fig. 1.8   Relationship  between  Influent Heavy  Metal Concentration
                     and Content  in  Activated Sludge
                                        -  450   -

-------
CHAPTER 2
OPERATION OF TORIHAMA INDUSTRIAL WASTEWATER PRETREATMENT
PLANT IN YOKOHAMA
                              CONTENTS
Introduction	 452
2.1. Outline of Industrial Wastewater Collective Pretreatment
    Facilities in Torihama District	452
    2.1.1. Features  	452
    2.1.2. Flow Sheets of Treatment Methods	452
2.2. Plant Operation  	454
    2.2.1. The Number of Advanced Enterprises and the Volume of Influent .  . . 454
    2.2.2. Results of Treatment	 456
2.3. Operation and Maintenance Cost	459
2.4. Problems and Countermeasures  	461
    2.4.1. Problems  on Management	461
    2.4.2. Technical Problems	461
    2.4.3. The Volume of Sludge Produced and Their Disposal	462
Conclusion	 465
                                    451

-------
Introduction
     The outline of the facilities  and treatment results obtained at the Torihama
Industrial Wastewater  Pretreatment  Plants  were reported  at  the  Third US/Japan
Conference on Sewage  Treatment Technology as an example of "Joint Treatment of
Industrial and Domestic Wastewater"
     Some  improvements  have been made  on the facilities and  operation at these
plants  have been generally satisfactory from  that time on. So we  would like  to
analyze the operational data  obtained  along with plant operation/maintenance cost
and technical problems  to be solved.
2.1.   OUTLINE  OF  INDUSTRIAL WASTEWATER COLLECTIVE PRETREAT-
      MENT FACILITIES IN TORIHAMA DISTRICT
     "Control  over  the sources" is the  basic rule to follow and the same holds true
with  industrial  wastewater we have  two approaches  to  choose from:  separate
treatment at individual  factories and collective treatment as a practical means to take.
Considering the  fact that,  at Torihama industrial district,  some  90 percent  of the
firms advanced into this industrial district are medium  and small  enterprises  with
employees  of  100  or  less, we have adopted,  rather than independent individual
treatment wastewater, joint pretreatment approach, to admit their wastewater into
public sewarage.
     Major  features and treatment methods are as follows:
2.1.1. FEATURES
(1)  The construction  and maintenance costs relating  to  the joint  treatment  of
industrial wastewater is a full  charge to constituent enterprises,  and the construction
and  operation/maintenance  activities are placed under the control of the City.
(2)  Industrial wastewater  is  classified into three types: miscellaneous wastewater
(from water closets, kitchens,  etc.), general process wastewater (containing organic
matter, oils, etc.), and pickling-plating process wastewater (discharged  from  pickling-
plating factories). Pickling-plating  process wastewater is further divided into  two
types,  that  containing  cyanide  and that contianing  heavy metals.  Each  type  of
wastewater  is led to the treatment plant through separate piping  and treated  properly
according to its particular physical and chemical properties.
(3)  Loans  of  comparatively low interest are being offered by  the City to medium
and small firms as a public nuisance prevention fund to help them finance their shares
of the joint wastewater pretreatment plant construction costs.
2.1.2. FLOW SHEETS OF TREATMENT METHODS
     Flow sheets of the  treatment methods are shown in Fig. 2-1.
                                     452  -

-------
                                                  Fig. 2—1 Flow-sheet showing treatment processes
                                                          at Torihama Industrial Waste Water Pretreatment Plant
                         Plant No.
                                                                                                              Plant No. 2
    (Heavy metals waste water)
    (Cyanide waste water)
                        Pump
                                       Pump
Primary oxidation
tank
                                             Storage tank
                     Secondary
                     oxidation tank
                                   Reduction tank
                                      I
                                  Mixing tank
                                                   Filtrate
                               Coagulation
                               sedimentation tank
-p*.
On
                             1
                                        Sludge
                                                   Vacuum filter
                                     Filter
                                       1
                                 pH controller
    (General process
    waste water)
                                  Relay pump
    (Miscellaneous
    waste water)
                                   Relay pump
                                                                                                      Sludge
(NOTE)
          Designed
          capacities
          Plant area
  Miscellaneous
  waste water
  General process
  waste water
 _ Cyanide
  waste water
  Heavy-metals
  waste water
r- Plant No.  1
L Plant No.  2
                                  4,333m3/day


                                  3,921 m3/day


                                     60 m3/day


                                    340m3/day

                                  1,097m2
                                  3,300m2
                                                             Sludge cake
                                                                                                                             Screen
                                                                                                                                                            Screen
                                                                                                                    Pump
                                  Pump
 Aerated grit
 chamber
                                                                                                                               J_
                                                                                                                          Oil separator
                                                                                                                               I
pH controller

     1
                                                                                                                 Mixing tank
                                                                                                                               I
                                                                                                              Coagulation
                                                                                                              sedimentation tank
                                                                                                                      I
                                                                                                                                      Aerated grit
                                                                                                                                      chamber
                                                                                                                  Thickener
                                                                                                                Sludge storage
                                                                                                                tank
                                                                                                                           Centrifuge
                                                                                                                                              ^Supernatant
                                                                                                                                                        Pressure pump
 Sludge cake
                                                                                                                                               tentrate
                                                                                                                             Nambu Sewage Treatment Plant

-------
 2.2.  PLANT OPERATION
     The Torihama Pretreatment Plant No. 2 has been in operation since April of
1972, and the Torihama Pretreatment Plant No. 1 since March of 1973. During the
two  or three  years of their operation, later changes have been incorporated in the
facilities to improve capabilities of the facilities, and their operating performance is
generally satisfactory from that time on.
     Servicing status from the beginning of plant operation until now is as follows:
2.2.1. THE NUMBER OF ADVANCED ENTERPRISES AND THE VOLUME  OF
      INFLUENT
     The year-by-year increase  in the  number of  constituent  enterprises  (firms
advanced into the industrial district) and the changes in the volume of influent during
the period from  the end of March, 1973, to the end of March, 1975, are shown in
Table 2-1.
     Although the  advance of enterpirses into the industrial district was initially
expected to end  by the  summer of  1974, the  depression by so-called "oil shock"
starting in late 1973 has been  holding back the  pace of advancement. And as of the
end of March,  1975, the advance rate (%) was approximately 76% with respect to the
object level,  while the volume of influent was only 22%  against the level  originally
planned, a fact far behind the object level.
                                    -  454  -

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        Table 2—1 The number of advanced enterprises and the volume of waste water
N. Items
Type of \.
wastewater \
Miscellaneous
General process
Pickling and
plating process
Enterprises
Planned
169
108
6
End of
March
1973
55
15
-
End of
March
1974
82
31
4
End of
March
1975
128
65
5

Advanced
rate in end
of March
1975
76 (%)
60
83
Total
Wastewater
Planned
4,333m3 /day
3,921
400
8,654
End of
March
1973
511 m3/day
317
-
828
End of
March
1974
1,064m3 /day
990
157
2,211
End of
March
1974
1,121m3 /day
709
104
1,934
Rate in
end of
March
1975
26 (%)
18
26
22
01
en

-------
     Particularly, the depression became apparent in every sector of the industry, and
enterprise operators' efforts  concentrated  on saving  water consumption  through
shorter-time operation  and  (or) improvements in processes resulted a decreased
drainage.
2.2.2. RESULTS OF TREATMENT
     The qualities of influent and clarified water by type of sewage  over the period
from January,  1975, to  the  end of May, 1975, are generally satisfactory  and are
shown in Tables 2—2 and 2—3, respectively.
                                      456

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Table 2-2  Results of Treatment at Plant No. 1 (Pickling/plating process wastewater)
Date
1975
1. 8


1.22


2. 5


2.20


3. 5


3.19


4. 2


4.30


5.14


5.28

Type of
wastewater
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Cyanide
Metals
Effuluent
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Hue
Colorless
Yellow
Colorless
Light yellow
Yellow
Light green
Colorless
Light green
Colorless
Colorless
Yellow
Light green
Colorless
Yellow
Light yellow
Colorless
Yellow
Colorless
Colorless
Green
Colorless
Colorless
Yellow
Light yellow
Colorless
Yellow
Light yellow
Colorless
Yellow
Colorless
Desired level
Odor
None
Cresol
Slightly cresol
None
None
None
Slightly phenol
Slightly phenol
Slightly phenol
None
Slightly phenol
Slightly phenol
Slightly phenol
Slightly phenol
Slightly phenol
None
Slightly phenol
Slightly phenol
None
None
None
None
Slightly phenol
Slightly phenol
None
None
None
Mineral oil
None
Slightly phenol

Water
Temp. (°C)
9
10
8
9
9
8
10
10
8
8
9
7
10
11
10
10
11
17
12
13
12
18
18
18
19
19
20
19
20
21

PH
__
2.3
6.2
11.3
2.4
8.1
12.8
1.1
7.8
12.1
1.6
6.8
12.0
3.6
8.9
12.0
2.1
7.4
11.3
1.8
8.0
11.6
1.3
8.3
10.7
2.2
9.0
12.6
2.2
7.6
5-9
CN
(mg/1)
_
10
0.04
220
10
1.4
230
10
0.03
350
2.5
0.37
460
2.0
1.0
300
3.7
Trace
140
1.0
0.15
92
0.67
-
130
0.93
0.03
250
2.6
0.04
1 or less
T-Cr
(mg/1)
_
7.7
Trace
1.4
83
1.8
2.0
4.0
Trace
_
—
-
0.17
55
0.11
_
—
-
1.2
92
Trace
Trace
92
1.0
_
—
-
1.5
69
0.67
2 or less
Cr+6
(mg/1)
Trace
54
Trace
Trace
53
0.23
Trace
Trace
Trace
Trace
80
Trace
Trace
31
Trace
Trace
120
Trace
Trace
Trace
Trace
Trace
49
0.5
Trace
320
0.26
Trace
41
Trace
0.5 or less
S-Fe
(mg/1)
	
37
0.36
9.2
21
0.46
3.7
2,200
Trace
_
-
-
4.8
26
Trace
_
—
-
1.3
1,400
Trace
1.9
46
Trace
_
—
-
3.2
16
Trace
1 0 or less
Ni
(mg/1)
_
7.2
Trace
1.2
16
0.39
0.71
0.71
0.31
_
-
-
0.42
6.7
0.54
_
-
—
0.79
7.8
0.53
20
10
0.33
_
—
-
0.60
7.3
0.32
1 or less
Cu
(mg/1)
__
9.8
3.1
12
11
5.3
11
7.2
4.7
—
-
-
6.8
4.7
8.0
—
-
—
7.4
28
7.3
8.0
16
0.90
_
—
-
3.2
7.6
2.5
3 or less
Zn
(mg/1)
_
6.7
1.1
140
76
0.66
160
180
1.2
—
-
-
330
51
1.0
_
-
—
94
210
1.1
47
160
1.1
_
—
-
250
100
2.4
5 or less
Pb
(mg/1)
—
2.9
Trace
0.49
0.56
0.24
Trace
0.43
Trace
_
-
—
Trace
0.21
Trace
—
-
—
Trace
Trace
Trace
Trace
1.3
Trace
_
—
-
Trace
0.54
Trace
1 or less
Cd
(mg/1)
—
Trace
Trace
Trace
Trace
Trace
Trace
Trace
Trace
_
-
-
Trace
Trace
Trace
—
-
—
Trace
Trace
Trace
Trace
Trace
Trace
_
—
-
Trace
Trace
Trace
0.1 or less

-------
                    Table 2—3 Results of Treatment at Plant No. 2 (General process wastewater)
t_n
00
\, Items
DateN\v
1975
1. 8
2. -5
3. 5
4. 2
5.28
Type
Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Influent
Effluent
Desired level
Hue
Turbid black
Light green
Turbid grey
Light green
Red brown
Light green
Red violet
Red violet
Black
Dark green
-
Odor
Meneral oil
Hydrogen sulfide
Mineral oil
Sewage
Sewage
Sewage
Sewage
Sewage
Sewage
Hydrogen sulfide
—
Water
Temp. (°C)
9.0
9.0
10.0
10.0
10.0
10.0
12.0
13.0
19.0
19.0
—
PH
7.0
7.1
7.6
8.5
8.8
8.3
7.2
6.8
7.5
7.4
5-9
BOD
(mg/1)
810
140
240
84
580
250
320
150
301
311
300
or less
COD
(mg/1)
370
100
250
100
220
110
130
110
210
210
—
ss
(mg/1)
580
160
110
39
140
44
240
10
100
10
300
or less
Oil
(mg/1)
210
43
46
35
32
21
120
26
38
16
35
or less

-------
     Unsatisfactory copper  treatment  is supposedly due to insufficient oxidation-
decomposition of copper cyanide, because copper in the cyanide wastewater forms
complex cyanide and as a result, copper still remains in  the effluent. You may also
notice  that hexa-valent  chromium is found in the cyanide  wastewater or cyanide is
detected in the heavy metals wastewater. This is generally attributable to, inspite of
the fact that  sewage pipings in individual factories are  so arranged as to  separate
wastewater by its type, incomplete isolation or misoperation by factory operators. To
correct  this condition which presents difficulties in proper treatment processes, we
have been keeping in touch with factory operators and providing them with necessary
information by holding guidance sessions for improved process methods and for more
strict plant management.
     Treatment of general process  wastewater at Plant No.  2 is generally satisfactory
with minimum variations in influent qualities in recent years.
2.3.   OPERATION AND MAINTENANCE COSTS
     Operation and  maintenance  costs including chemicals,  lighting  and  heating
expenses, power, personnel,  sludge (waste oil) disposal and pipe cleaning expenses are
totally charged to constituent enterprises.  Allotment of these expenses is based upon
the quantities and qualities of wastewater discharged from individual firms.
     Shown in Table 2—4 are the quantities of water treated by type of wastewater,
operation/maintenance cost, and treatment cost per one cubic meter of wastewater in
1974, as contrasted to those in 1973.
     In the 1974  operation cost, because the inflation  initiated by the late  1973
energy crises pushed up  such  expenses as power,  personnel, and chemicals 30 to
100 percent, the unit cost of pickling-plating process wastewater treatment increased
to a very high level.
                                   -  459  -

-------
         Table 2—4 The volume and operation/maintenance cost of wastewater
Type of
wastewater
Miscellaneous
General process
Pickling/plating
process
Total
1973
Processed volume
264,338m3 /year
179,224
73,096
516,658
Operation/maintenance
cost
3, 774,000 yen/year
10,956,000
15,386,000
30,116,000
Average cost
per 1 m3
14.3 yen/m3
61.0
210.5

1974
Processed volume
379, 116m3 /year
272,433
45,571
697,120
Operation/maintenance
cost
8,356,000 yen/year
14,605,000
15,113,000
38,074,000

Average cost
per 1 m3
22.0 yen/m3
53.6
331.0

CTv
O

-------
     As for pickling-plating process wastewater in particular, unusual increase in it is
responsible  for a substantial  drop in  the volume of discharged drainage, as it was
described earlier, because of the depression.
2.4.   PROBLEMS AND COUNTERMEASURES
2.4.1. PROBLEMS ON MANAGEMENT
(1)  Treatment Capacities of Collective Pretreatment Facilities
     The  Processing capacity  of  this  plant  was decided on the basis of estimates
provided  in reports  from individual enterprises as to the quantities and qualities of
wastewater  before the plant was constructed and placed into service. As a result, it is
difficult for the plant to allow constituent  enterprises to  increase their drainage
volumes or change  the qualities  of their wastewater along with development and
expansion of their business activities.
     In view of our  experiences with the plant, therefore, it  is desirable, to design a
plant  with  flexibility in  its  capabilities to  some extent to  accommodate  future
expansion,  when  a  new collective pretreatment facility construction plan, will be
made.
(2)  Official Determination of Wastewater Qualities
     As  for the  determination   of quality  of wastewater,  individual enterprise
operators are required to submit a report on it. We found however that  these stated
qualities in  many cases differ greatly from the  fact and lack reliability. Therefore, it is
desirable that measurements be made by city officials.
(3)  Expense Allotment of Operation/Maintenance Cost
     Operation and maintenance costs  are computed on a liquidation principle at this
plant, and this  system on a year-by-year expense allotment basis has experienced such
a shortcoming: highly varying unit cost of treatment in consequence  of such factors
as decreased drainage resulting from a depression and soaring management costs by
inflation,  could be quite a burden to enterprise in carrying their business activities.
     For this reason, it is  desirable that the present system should be replaced with a
new expense allotment system based on revising service fees every two or three years
service fees offered at regular rates  for two or three years.
(4)  Nonfulfillment  of Management Contract (delayed allotment payment, nonper-
formance of water quality reporting obligation, etc.)
     Because of the fact that the City takes primary responsibility for plant operation
and  maintenance,  there  appears   a  tendency  that  enterprise  operators  are  less
conscious about their  responsibility than before, and  in fact,  we have difficulty in
obtaining cooperation  from   some  of  the  operators  with nonperformance  of
management contracts, etc.
2.4.2. TECHNICAL PROBLEMS
(1)  Treatment of Wastewater Containing Oils and Fats
     At this collective pretreatment plant, waste oils and fats isolated and removed by
aeration system. However,  isolation performance is not satisfactory  because of the
fact  that  various kinds of oils and fats are  admitted to the facilities. To adopt  a
treatment method best suited  for the properties of oils in a  free or emulsified state,
therefore, we believe that an individual treatment is more efficient than  a collective
treatment.
(2)  Pickling-Plating  process Wastewater Treatment
     Pickling-plating  wastewater was divided into two types, that containing cyanides
and that containing heavy metals.  But  further seperation of the latter was impossible
for reasons  of  complexity and technical difficulties of piping, so that chromium
                                      461

-------
waste water and acid/alkaline wastewater were allowed to flow in one piping system.
As a result, we faced the following problems:
1)   Treatment of heavy metals is as follows: the hexa-valent chromium is reduced to
trivalent chromium first by lowering its pH value and then, by increasing its pH value,
it is separated  together  with  other metals, and  removed as hydroxides.  But this
process changes not only the pH value of  the chromium wastewater, but also that of
the acid/alkaline wastewater, and as a result the consumption of pH adjusting agents
such as sulfuric acid  and calcium hydroxide increased.  It also meant extra sludge
production and added operation cost.
2)   Hexa-valent chromium reduction is conducted by automatically controlling the
feed rate  of chemicals  in proportion  to the pH value  and oxidation-reduction
potential.  But  because  the oxidation-reduction potential is affected by iron ions,
contained substantially in the alkaline wastewater, to compensate for this condition a
reductant is added  slightly more than that normally required.
3)   It  is  a generally suggested rule  that concentrated wastewater produced from
plating factories be pooled temporarily within the factories and then drained in small
quantities so that  it is sufficiently diluted with usual wastewater. However, diluting
operation by individual firms isn't always performed satisfactorily.
2.4.3. THE VOLUME  OF SLUDGE PRODUCED AND THEIR DISPOSAL
(1)   Plant No. 1
     The  1974 plant  operation records show  that sludge cakes (moisture  content
80%) averaged 880 kilograms a  day in weight.
     Because pickling-plating process wastewater is treated in this plant, sludge cakes
contain such materials as heavy metals. It is necessary, therefore, that some means be
employed  so that they would not ooze out of sludge cakes upon disposal. The means
applicable we have experimented or studied so far are (1) solidification with concrete,
(2)  sintering, (3)  melting, (4) reduction sintering,  and (5)  colliery reuse (bringing
them back to refineries  as raw materials). As  a result, considering such factors as
feasibility  and prevention of further leaching, sintering method is under consideration
as the one of practical approaches today. As for this method, a flow sheet along with
part of its experimental results was summarized in  the previous report. And this time,
it  is  presented  in the  following  Table  and  Figures  together  with its  possible
application to synthetic aggregate.
                                   -  462  -

-------
            Table 2-5  Physical characteristic of sintered sludge
Sintering
additives
Clay
Clay
Clay
Clay
Clay
Clay
Clay
Clay
Refractory
material
Refractory
material
Refractory
material
Grit-stone
Blending ratio
Plating
sludge : Clay
1 : 1
1 : 2
1 : 3
1 : 4
1 : 4
1 : 4
1 : 5
1 : 6
1 : 3
1 : 3
1 : 3
-
Sintering
temperature
(°C)
1,100
1,100
1,100
1,100
1,150
1,200
1,200
1,200
1,100
1,150
1,200
-
Sintering
time
(Minute)
60
60
60
60
60
60
60
60
60
60
60
-
Granulating
method
By machine
By machine
By machine
By machine
By machine
By machine
By hand
By hand
By machine
By machine
By hand
-
The state of sintered sludge
Half fused, Black-brown
Sinter, Black-brown
Sinter, Brown
Sinter, Light red-brown
Sinter, Brown
Sinter, Brown
Sinter, Brown
Sinter, Brown
Half sinter, Black-brown
Sinter, Black-brown
Half fused, Black-brown

Strength of crushing (kg)
Average
39
52
25
25
35
59
93
105
15
45
96
57
Min.-Max.
35- 47
44- 69
20- 30
20- 32
20- 44
49- 69
86- 98
93-113
15- 15
44- 47
60-123
44- 69
Specific
gravity
-
-
-
2.1
1.7
1.6
1.8
2.1
2.1
2.2
2.3
-
Water
absorb
(%)
-
-
-
2.7
3.0
0.03
0.82
0.67
12.9
0.84
0.47
-
-pi
Os

-------
                       Fig. 2—2  Solubility test of various PH in elutriate
                                                               Fig.  2—3 Sintering temperature and solubility of chromium
            0.7
           0.6-
Concentration
of heavy metals
in elutriate 0.5-
           0.4-J
           0.3'
Plating sludge : Clay =1:4
Sintering Temperature   : 1,150°C
Sintering time           : 60 minute
           0.2-
     (mg/1)
           O.H
                     1      2
                                    PH in elutriate
U.7-
0.6-
Concentration
of chromium
in elutriateO.5-
0.4-

0.3-


0.2-
(mg/1)
0.1-


Clay (1:4)
30 minute \
\
\
\
\
•
Clay (1 : 3) \
60 minute N. •.

Clay (1 : 4) >v \
60 minute "^.^^^^^^ >v\
Refractory material TT~"77 	 .X\ _
60minute ~..:_:Y_..__7?-, 	 "" ' —
i.i'oo u'so i
	 »• Sintering temperature (°C)
                                                                                                                   1,200

-------
(2)  Plant No. 2
     The 1974 operational records show that sludge cakes (moisture content 80%)
averaged 435 kilograms a day. Because their composition is much the same as that of
domestic sewage, they are disposed as land fill, together with sludge produced from
other sewage treatment plants.
Conclusion
     The example we presented in this report is a counter measure against industrial
wastewater  which has been  planned and practiced on the premise that industrial
wastewater from medium and small enterprise districts are allowed to flow into public
sewarage. We believe that this approach is one of the most efficient ways, at least for
the time being,  and acceptable by to small and medium enterprises that can hardly
afford, technically and financially, an independent treatment.
     We  are generally satisfied with the operational results obtained, however, (1)
enterprise operators' sense  of responsibility for their fulfillment of obligations, (2)
with the plant's  capacity being inflexibly fixed, it is incapable of meeting quantitative
and  qualitative changes of wastewater resulting from variations in business activities
of constituent enterprises, (3) final  disposition of  sludge, and (4)  indiscriminately
mixed  up inflow of  various wastewaters are  among the problems we must solve
urgently.
                                    -  465  -

-------
CHAPTER 3.  FUKASHIBA INDUSTRIAL WASTEWATER TREATMENT
             PLANT IN IBARAGI PREFECTURE
3.1   General Plant Review	467
3.2   Quality and Quantity of Industry Wastewater	467
3.3   Charge	469
3.4   General Condition of Maintenance and Operation	469
3.5   The Present Sludge Disposal	469
3.6   Problems	469
                              - 466 -

-------
3.   FUKASHIBA  INDUSTRIAL  WASTEWATER  TREATMENT  PLANT  IN
     IBARAGI PREFECTURE

     The description of this plant was informed at the first U.S.-Japan Conference
Sewage Treatment Technology  in 1971 and the general survey of the  maintenance
and operation of the plant from  Sept., 1971 to June, 1975 is given below.

3.1  GENERAL PLANT REVIEW
     This treatment plant was designed to provide preliminary and secondary treat-
ment to the wastewater of the  oil refineries and the petrochemicals  existing in the
area of 1,800 ha except steel mills area in  the Kashima industrial district of 2,400 ha
and the future wastewater flow is estimated about 300,000 m3 /day.
     The preliminary treatment facilities include grit chambers, oil floatation tanks,
pH control tanks and  the chemical coagulation and settling tanks  by which B.O.D.
load for subsequent biological process is reduced and the hazardous  substances for
metabolism are removed as much as possible.
     The  secondary  treatment  facilities  include aeration tanks and  final setting
tanks, operating as a conventional activated-sludge system for purpose of the stabili-
zation of final effluents. The secondary facilities also may be operated as a two stage
activated-sludge system if necessary, in case of the striking fluctuation of influent
quality.
     In order to prevent  the transpiration of odor arising from plant  site, Oil floata-
tion tanks, pH-control tanks and sludge  thickeners are covered  with lids and the
odor is  removed by  a soil adsorption process or an activated carbon absorption
process.
     Sludge is mechanically dewatered after thickening and then to be incinerated.
(Fig. 1)

3.2  QUALITY AND QUANTITY OF  INDUSTRY WASTEWATER
     Effluent of Fukashiba Wastewater Treatment Plant is discharged  into the sea of
Kashima and the effluent standards are established by Ibaragi Prefectural Regula-
tions as shown in Table 1.
     In order to meet the regulations, it is required that the strength of influent into
the treatment plant should not exceed approximately 200 mg/fi of COD,  250 mg/C
of suspended solid and 10 mg/£  of Hexane Solubles.
     Therefore, each industry is demanded annually to report quantity and quality
of his wastewater to administrative office. The data are adjusted and effluent criteria
for each industry (agreement rules) are determined (Table 2).
     Most of industries  are required pre-treatment facilities  to meet the criteria.
The existing pre-treatment facilities are as  shown in Table 3.
     The kinds of the facilities are mostly pH control tanks, sedimentation tanks
and oil separators. Some  factories are required special treatment  equipments such
as stripping towers to remove volatile organic matters and spray incineration equip-
ments to treat high-COD wastewater.
                                    467

-------
                                   REFERENCE
       S.  Matui, Activated Sludge Degradability of Organic Substances in the Waste-
  water of the Kashima Petroleum  and Petrochemical. Industrial Complex in Japan,
  7th  International  Conference on  Water Pollution  Research, Paris, Sept.  9 ~  13,
  1974.
Influent
                                      Air
                                      _L
Air  Chem leal agents
i	L


f Return sludge
it

j
Execess s
c
o.
oq
o
CD
o.
CD
» Po
c"
p.
(TO
01






tanKs 	 — tanks
1.5 h
_J ! f
vOily scum \
/' /
. ' Exhaust gas .
i 	 »J
gulation tanks
3. Oh
Air
4



Aeration tanks
6.0 h
yelectrolytc
Sludge j
^-*-^ \
f >w ( I*1 Soil filte
1 Thickners 1 ^J
Grit chambers \ / 1
i ^~ 	 ' Activate
^upernatant «» -^

s Dewatering
facilities
Final settling tanks
3.0 h
Chlorine


Chlorination tanks
Filtrate Cake

I Incinerators
1 ,
j (Under construction)
1 	 p 	 1
t
                                                      (Ash	_    Landfill)
                        Effluent
                    Fig. 1 Process Flow of Fukashiba Wastewater Treatment Plant
                                   - 468

-------
3.3  CHARGES
     Quantity and Quality  Charge System is applied for all  industries discharging
into the sewers
     Namely,  below the agreement rules, the charge is calculated  by using the
Quantity and Quality Charge formula. If the quantity and/or quality  of wastewater
from any factory exceed the agreement, surcharge is levied to the wastewater below
the effluent standards of Sewerage law. And exceeding the effluent standards of the
Sewerage law, penalty is imposed.  (Table 4)
     Each factory is required to install flow meters, partial type or electromagnetic
type in order to measure the wastewater quantity which is the basis of the  assess-
ment of the charge. Each factory  also is required to install automatic pH recorders,
Toe meters  etc. In addition, the continuous monitoring and the occasional quality
examinations of once to four times a month are performed to secure the effect.

3.4  GENERAL CONDITION  OF MAINTENANCE  AND OPERATION
     The data of operations of this treatment plant in each month from January to
June, 1975 are as shown in Table 5.
     Most of industries keep  operating  continuously around the clock  and the
fluctuation of quantity and quality is little. However, the strength of chlorine ion is
approximately 3,500 mg/£ and seems to be higher than in influent into other treat-
ment plants.
     The removal rate  of suspended solids is high in chemical sedimentation tanks
and  80%, but those of BOD, COD  and Haxane Solubles are low and 38, 15 and 33%,
respectively.
     And the removal  rates of them are high in final settling tanks except Haxane
Solubles and B.O.D., C.O.D. and  Suspended Solids are 90, 70 and  50% removal,
respectively. But the removal rate of Haxane Solubles is 25% and it is as almost same
as in chemical sedimentation tanks. (See Table 4)
     Besides, 1  mg/C of polyelectrolytes such as polyethylene aluminium chloride is
added in final settling tanks  to promote sedimentation of sludge floes.

3.5  THE  PRESENT SLUDGE DISPOSAL
     Sludge is  drawn  from chemical  sedimentation  tanks and concentrated. De-
watering is done by Filter Press Method on a dosage of about  19 to 31% slaked lime
of dry solids. Sludge cakes  are disposed by land fill, but incinerators are now under
construction and they are to be completed in Dec., 1975.
     And these sludge cakes are planned to be utilized as soil enrichment agents and
fertilizer for plants in the sandy soil and the pot studies and the field  plot examina-
tions of 3,000 m2  farm  are provided.
     The results of analysis of heavy metals contained in the sludge cakes and the
results of elution tests are as shown in Table 6 and 7 and there are no problems.
3.6  PROBLEMS
1.   In the  annual routine  maintenance of industries BOD load and chlorine ion are
     strikingly  reduced, the operating control is difficult and the effluent quality
     sometimes grow worse.
2.   As the industrial  wastewater sometimes contains high reducing  materials, it is
     necessary that Dissolved Oxygen in the aeration tank, is kept high level.

                                     469

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               Table 1   Effluent Standards for the Sea of Kashima
Constituent
1. Cadmium (Total)
2. Cyanide
3. Organic phosphide
4. Lead (Total)
5. Chromium (Total hexavalent)
6. Arsenic (Total)
7. Mercury (Total)
8. Alkyl mercury compounds
9. pH
10. C.O.D.
11. Suspended solid
12. Fecal coliforms
13. Hexane solubles (Mineral oils)
(Fats and fatty oils)
14. Phenols
15. Copper (Total)
16. Zinc (Total)
17. Iron (Dissolved)
18. Manganese (Dissolved)
19. Chromium (Total)
20. Fluoride (Total)
Concentration (mg/£)
1971
0.1
1
1
1
0.5
0.5
ND
ND
5.0-9.0
120 (100)*
60 (50)*

7(5)*
7(5)*
5
3
5
10
10
2
15
1975
0.1
1
1
1
0.5
0.5
0.005
0.005
5.8-8.6
50 (40)*
50 (40)*
3,000
3(2)*
3(2)*
5
3
5
10
10
2
5
* Daily average values are shown in parentheses.
                                      470

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Table 2  Agreement Values (1977)
Factories
Tobu
District
1
2
3
4
5
6
7
8
9
10
11
12
13
(14)
15
16
17
18
19
20
Seibu
District
(21)
(22)
23
(24)
25
26
27
(28)
29
(30)
(31)
Discharge
m3/day
15,500
1,830
35
1,910
11,000
400
4,700
14,100
2,300
5,000
6,700
250
3,500
2,000
9,500
3,000
1,500
300
100
100
150
200
195
3,790
2,000
30
9,000
1,340
208

4,000
pH

5-9
5-9
6-9
5.5 - 8.5
5-9
5-9
5-9
5-9
5-9
5-9
5-9
5-9
5.8 - 8.6
6-8
5-9
6-8
5-9
6-9
5-9
5-9
6-8
6-8
6.5 - 8.6
5 -9
5-9
7.0
5-9
7.5
6-8

6-8
B.O.D
mg/£
80
250
150
249
470
90
150
160
27
270
60
50
100
250
200
60
30
300
15
350
150
50
220
300
200
100
300
10
100

25
C.O.D.
mg/C
80
300
150
242
300
70
300
160
41
200
150
150
220
250
300
60
30
250
100
300
150
50
160
150
80
100
300
20
100

20
Suspended
solid
mg/£
15
80
200
65
170
300
30
40
35
40
65
100
" 25
100
50
50
40
50
100
50
200
50
160
50
90
100
30
20
80

50
Haxane
solubles
mg/C
15
6
0
7
15
3
10
3
8
10
5
6
8
3
5
5
10
10
10
20
5
1
10
10
20
0
10
0.5
7

20
Factories

(32)
Hazaki
District
(33)
(34)
35
(36)
37
(38)
(39)
(40)
(41)
(42)
(43)
(44)
(45)
(46)
(47)
(48)
(49)
(50)
(51)


Total
Discharge
m3/day
1,000
600
720
5
180
200
710
520
21
126
90
272
1,400
640
221
249
270
810
54
1


112,727
pH

5-9
5-6
6-9
5.8 - 8.6
5.5 - 8.5
6-8
5-9
5.7 - 8.7
5.6 - 8.6
6.5 - 8.0
5.5 - 8.5
6.5 - 7.5
5-9
6-8
6-8
6.5 - 8.5
7
6.5 - 8.5
5-9
6-8


5-9
B.O.D
mg/£
20
300
250
22
50
60
10
100
90
300
70
100
300
300
68
60
22
20
5
30


186
C.O.D
mg/£
40
200
100
22
50
10
20
100
80
300
140
200
300
300
37
40
38
10
16
30


182
Suspended
solids
mg/£
20
50
10
10
20
50
50
200
250
40
50
20
20
150
18
90
70
15
10
30


57
Haxane
solubles
mg/C
7
7
5
5
5
1
10
6
0
5
7
5
10
10
1
4
4
5
0
5


9




Future industries are shown in parentheses.



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Table 3  Existing Pre-treatment Facilities
Factories
1
2
3
4
5
6
7
8
9
10
11
12
13
15
16
17
18
19
20
25
27
35
Total
pH control
tanks
o
o

o
o
o
o
o

o
o


o
o
o
o
o
o

o
o
17
Oil
separators
o



o







o


o
o
o

o


7
Sedimentation
tanks
o
o

o
o


o
o


o
o
o
o




o
o

12
Activated
sludge facilities




o




o
o











3
Others

Stripping tower













Stripping tower




Spray incineration equipment


               -  472

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   Table 4  Industrial Wastewater Charge System of Fukashiba Wastewater Treatment Plant
           (Effective April!, 1975)

        Charge = quantity charges + quality charges + surcharges + penalties

 1.  Quantity charges
    32 yen per m3 per a day of quantity (Qe) (10 yen in 1971)
    Where;
    Quantity (Qe) (m3 /day) = Q (below of 3,000 m3 /day)
    or
                      = 3,000 +0.9 (Q-3,000)
                       (exceed Q of 3,000 m3/day and below Q of 5,000 m3/day)
    or
                      = 4,800 + 0.8 (Q- 5,000)
                       (exceed Q of 5,000 m3/day)
    Q is a daily average flow (m3 /day) which is measured by a flow meter.
2.   Quality charges
    Quality charge per m3 per a day of "Q" is as follows:
Strength (F)

F<120
120^F<240
240 ^ F < 360
360 ^ F < 480
480 ^ F < 600
600 ^ F < 720
720 ^ F < 840
840 ^ F < 960
960 ^ F < 1080
1080 ^F< 1200
1200 ^F< 1320
Charges
1971
Yen
4
6
8
10
12
14
16
18
20
22
24
1975
Yen
20
30
40
50
60
70
80
90
100
110
120
    Where;
    in which B, C, S and N are BOD5 , COD, SS and Hexane Solubles in mg/£ which
    are determined due to analize samples, respectively.
                                   - 473

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3.   Surcharges
(1)   When quantity of "Q" exceeds 110% of the agreement values, 64 yen is payed
     for each m3 per a day of excess quantity over the agreement values.
(2)   When the strength of the wastewater exceeds 120% of the agreement values,
     the following charges are payed for each m3 /day of quantity of "Q".
Surcharge (yen/m3/day)
1971 1972
3 12
6 24
10 40

When "F" based on the determined strength is below "F"
based on the agreement values or exceeds one step over it.
When "F" based on the determined strength exceed two
steps over it.
When "F" based on the determined strength exceeds three
steps over it.
 4.   Penalties
     When the determined strengths of any constituents of wastewater exceed the
 following standards, penalties of 40 yen (10 yen in 1971) per m3 per a day of
 quantity is imposed for each item of violation.
Items
Temperature
PH
BODS
COD
Suspended solids
Hexane solubles
Others
Criteria
45°C
5 ^ pH ^ 9
600 mg/£
600 mg/C
600 mg/K
20
Those required by
the administrator.
                                   -  474 -

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Table 5  Monthly Operation Data of Fukashiba Wastewater Treatment Plant
Month
1975
Jan.
Feb.
Mar.
Apr.
May
June
Avg.
Influent
Quantity
(m3/day)

42,800
51,800
55,400
56,300
56,500
56,100
53,200
Temperature
(°C)

22
21
22
26
30
29
25
PH

7.4
7.6
7.4
7.5
7.5
7.6
7.5
BOD
(mg/0

184
84
154
103
107
106
123
COD
(mg/0

144
145
158
132
118
127
137
Suspended
solids
(mg/0

155
190
116
115
72
63
119
Hexane
solubles
(mg/0

7
6
6
5
6
5
6
Chlorine
ion
(mg/0

2,790
2,330
2,700
4,110
4,390
3,430
3,290
Aerated oil
separators and
pH control tanks
Cu.M. ail
per Cu.M.
wastewater

4.6
3.7
3.9
3.0
3.4
3.7
3.7
Chemical coagulation tanks
Detention
time
(hr)

6.2
3.5
3.0
3.0
3.0
3.7
3.7
BOD
(mg/0

82
71
101
64
66
73
76
COD
(mg/fi)

119
128
141
107
99
104
116
Suspended
solids
(mg/fi)

14
15
33
19
40
10
24
Hexane
solubles
(mg/0

3
4
4
4
4
4
4
Month
1975
Jan.
Feb.
Mar.
Apr.
May
June
Avg.
Aeration tanks
Cu.M. air
per Cu. M.
wastewater

10.6
8.5
9.0
7.0
8.1
8.7
8.7
MLSS
(mg/0

3,750
3,870
3.970
3,250
3,710
3,350
3,650
VSS/SS
(%)

86.5
86.5
82.1
79.8
76.7
78.8
81.7
SVI

51
46
46
46
47
48
47
MLDO
(mg/0

4.3
4.7
5.8
6.0
3.8
4.1
4.7
Excess
sludge
(Ton/dry
solid/day)

0.67
0.76
0.62
0.67
1.03
1.30
0.84
Return
sludge
ratio
(%)

25
23
23
23
21
22
23
Final settling tanks
BOD
(mg/0

7
6
6
3
7
10
7
COD
(mg/0

33
35
33
30
40
36
35
Suspended
solids
(mg/£)

12
8
15
17
7
12
12
Hexane
solubles
(mg/0

2
3
3
3
3
3
3
Coagu-
lant
(mg/0

2.0
1.5
0.8
0.2
0.6
1.3
1.1
Thickener
Sludge
volume
(m3/day)

115.9
188.3
213,3
185.2
161.2
181.6
174.3
Water
contents
(%)

93.1
94.2
95.2
94.2
94.9
94.1
94.2
Dewatered sludge
Dosage
CaO
(%)

21.3
30.0
23.9
19.1
22.1
31.4
23.6
Weight of
sludge cakes
(Ton/dry
solid/day)

10.5
15.4
13.2
13.1
10.6
14.7
13.1

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                      Table 6  Heavy Metals Contained in Sludge Cakes
                                                                   (mg/kg of dry solids)
Month
Cadmium
Lead
Chromium
Iron
Copper
Zinc
Manganese
Nickel
Arsenic
Mercury
1975
Jan.
4.0
220
1,048
880
1,840
195
264
208
4.0
-
Feb.
5.2
17
770
324
1,280
1,104
268
184
7.5
-
Mar.
6.4
38
920
1,100
720
1,400
198
180
1.6
-
Apr.
8.7
133
1,320
960
780
2,400
296
700
8.5
-
May
7.8
25
4,640
1,420
668
1,440
238
180
2.2
-
June
8.8
92
1,300
725
432
834
208
100
3.6
0.012
      Table 7  Strength of Heavy Metals in Supernatant in Elution Tests for Sludge Cakes
Sample*
Mercury (Total)
Alkyl Mercury
Cadmium (Total)
Lead (Total)
Organic Phosphide
Chromium (Total Hexavalent)
Arsenic (Total)
Cyanide
Dry Solid**
I
ND
ND
0.01
0.05
ND
ND
ND
ND
42.6
II
ND
ND
ND
ND
ND
ND
ND
ND
42.6
III
ND
ND
ND
ND
ND
ND
ND
ND
42.6
Criteria
0.005
0.005
0.3
3
1
1.5
1.5
1
-
 * Samples were prepared as follows:
     Sample I:    10 g of sludge cakes was added to 90 g  of water and  the range of pH was
                 adjusted 5.8 to 6.3. Sample was mixed 6 hours and filtered with filter paper.
     Sample II:   As same as Sample I except pH range of 7.8 to 8.3.
     Sample III:  3 g of sludge cakes was added to 97 g of water and the  range  of pH was
                 adjusted 7.8 to 8.3. Sample was mixed 6 hours and filtered with filter paper.
** Expressed in per cent.
                                          476

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CHAPTER  4.  DESIGN AND OPERATION OF DYING WASTE TREATMENT
             FACILITY IN SABAE CITY, FUKUI PREFECTURE
4.1  Production of Coagulant "Activated Diatom Earth" from Diatomaceous
    Rich in Clay and Its Features	478
4.2  Planning Design and Operation of Dying Wastes Treatment Facility
    in Sabae City, Fukui Prefecture	479
                                477

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4.   DESIGN AND OPERATION OF DYING  WASTE TREATMENT  FACILITY
     IN SABAE CITY, FUKUI PREFECTURE
4.1  PRODUCTION OF COAGULANT "ACTIVATED DIATOM EARTH" FROM
     DIATOMACEOUS RICH IN CLAY AND ITS FEATURES
     The Noto Peninsula, lying  in the north of Honshu, abounds in diatomaceous
earth containing clay and vocanic ash. Its estimated amount of reserves is said to be
as much as several thousands of millions of tons.  (See Gig. 4.1)
     The average composition of the diatomaceous earth produced in the Peninsula
is  Si02  average  70%, A12O3   8-11%,  Fe2O3  4-6%,  CaO  0,5-1.4%,  NgO
0.2-0.25%, and Na2O +  K2O  1.5-3%, with the  content of SiO2  considerably
lower as compared with ordinary one. For this reason, it has not  been used as
filter agents so far.
     The Ishikawa Prefectural Industrial Laboratory has investigated  the commer-
cialization of diatomaceous earth buried in the ground in the Noto Peninsula for the
purpose of promoting local industries.  Their efforts have  turned out a  coagulant
under the trade name of "Activated Diatom Earth".
     The production process  of this coagulant is shown in Fig. 4.2. Namely, turned-
up diatomaceous  earth is dried, pulvulized, added with water and sulfuric acid,
baked in a rotary kiln at a temperature of 250  to 350°C and  again pulvulized as a
final product. By baking  after being added with water and sulfuric acid, the  earth
has its aluminum  oxide changed into aluminum sulfate and ferric oxide into  ferric
sulfate, thus gaining a ability to  coagulate suspended and coloidal solids. Its ability
combined with the adsorption force of diatomaceous earth, is displayed to the full
for coagulation.
     The coagulant, "Activated Diatom Earth", finds itself in the treatment of some
kinds of dying waste and oil containing waste.
     In Japan, the guidelines  concerning the industrial  effluent limitations have not
yet specified that for colour.  Effluents from dying mills largely vary in pH and
contain a considerably large  amount of organic substance. The most problematic
among others is  their own hue  and colour  of  the waste,  which in many cases  is
serving a main  cause of trouble with neighbors and downstream inhabitants and
farmers.
     As a consequence, the methods of reducing the colour of effluents from dying
mills have long been investigated for all that  they are not specified in the guidelines.
The  coagulant, "Activated Diatom  Earth", is excellent in  colour reduction of ef-
fluents from dying mills. Table 4.1 shows colour reduction effects and KMnO4-COD
removal in chemical coagulation of various kinds  of dye solutions.
     According to laboratory  tests, the Coagulant is able to treat wastes of dispersion
dyes, acid dyes, naphtol dyes and vat dyes to discolour to  perfection. Also, it goes
a long way with the colour reduction of direct dyes, reaction dyes and base dyes.
     As  regards waste of sulfide dyes, it has little or no  efficacy; rather, ferrous
sulfate is more effective as a  coagulant. "Activated Diatom  Earth" has  the optimum
pH depending on  the kinds of dyestuffs at which its colour reduction performance
                                     478

-------
can be exhinited best.
     Fig. 4.3 shows the pH vs. colour reduction relationships for acid dyes (Suminol
Leveling  Red 3B),  base  dyes (Aizen Cathilon  Red K-GLH), and dispersion dyes
(Resoline Blue BR).
     Another feature of  the Coagulant is notable dewatering effect when applied
to sludge, and still more important is the fact that the dewatered cake can be used.
Excellent dewatering effect is attributable to diatomaceous earth in the Coagulant.
The dewatered cake has been mixed with cement and molded into artificial trees or
stones for use at parks and gardens.
     Recently, a method of manufacturing filter agents from dewatered  cakes has
been  developed and  industrialized. Since the dewatered cakes can be turned into
secondary products,  the  manufacturer of the Coagulant has been carried out busi-
ness  taking  over  dewatered cakes  free of charge at users' treatment plants while
suppling the Coagulant "Activated Diatom Earth".
     Fig. 4.4 shows  a flow sheet explaining the production process of filter agent
from  sludge cakes.

4.2  PLANNING DESIGN AND OPERATION OF DYING WASTES TREATMENT
     FACILITY IN SABAE CITY, FUKUI PREFECTURE
     Sabae City, in Fukui Pref., developed the  Eastern Industrial Estate, and has
made efforts to attract manufacturing businesses.
     Now there are some dying mills in  the  Estate, and the  water quality of the
Kurozu River which  is receiving their effluents is hideously bad. The inhabitants of
downstream  of the Kurozu River  lodged strong protests against Sabae Municipal
Office, claiming to improve water quality.
     Meanwhile, the Office planned to construct  sewarage system to cover the entire
unban areas and a sewage treatment plant.
     But, the plan was thought to take too much  time to prevent the water pollution
of the Kurozu River. Besides, it was feared that the improvement of the secondary
effluent in hue and colour at the sewage treatment plant could hardly be expected
if the wastewater of dying mills were accepted with domestic sewage by the public
sewers.
     To cope with this problem, the Sabae Municipal  Office has planned to con-
struct a joint pretreatment facility where dying wastewater are treated by a chemical
sedimentation process to remove color and a part of organic substances.
     While the effluent from the facility is planned to be discharged into the Kurozu
River for the time being,  it will be  treated again at the municipal sewage treatment
plant  in  future, mixed with domestic sewage. In preparation for this plan, the Public
Works Research Institute, Ministry  of Construction, took a part, and discussed with
engineers of both the Municipal Office and the Dying Industry Cooperative Associa-
tion several times.
                                  - 479  -

-------
     As a result,  the aforesaid  coagulant, "Activated Diatom Earth", was decided
upon as the coagulation agent for the Joint Pretreatment Facility.
The  reasons are as follows.
i)    Of the dyestuffs used in the mills in the Sabae Eastern Industrial Estate dis-
     persion dyes  occupy the majority. Others, including acid dyes, naphtol dyes
     and reaction  dyes, are  also used. From basic experiments in the past, it has
     been corroborated that the coagulant "Activated Diatom Earth" is effective in
     colour reduction of these dyes.
ii)   Although the Activated Diatom Earth was priced at ¥25 per kg  at that time,
     far more expensive  than other coagulants, and its dosing rate was as high as
     1,000 ppm,  the latter was expected to be whittled away sharply if technical
     investigation has been set  up.
iii)  The settled sludge can be  dewatered to a 70% of water content by a vacuum
     filtration without filter agent. Fortunately, the manufacturer of the coagulant
     "Activated Diatom  Earth" has commited themselves to  take over dewatered
     sludge for making filter agent.
iv)  From the above, it is expected that the total costs, including the cost for treat-
     ment  and disposal  of settled sludge, will become  cheaper than with other
     coagulants (e.g., aluminum salts, ferrous salt,  ferric salt etc.).  Still another
     advantage is  no need of preparation of the land required  for disposal of sludge.

     As the coagulant, "Activated  Diatom Earth", was picked up for the treatment
of waste from the dying mills, various experiments have been  carried out to find the
way to minimize the dose rate of the coagulant and the way to keep stabilized
operation of the pretreatment facility.  The results are  as follows.
i)    The  waste from the dying mills are very changeable in  its flow  and quality
     from  time to time. It is therefore necessary to install an equalizing pond. The
     capacity  of  the pond is estimated to be at least four-hour's worth of hourly
     maximum waste water flow in order to keep stable operation of the joint pre-
     treatment facility.
ii)   If the waste  of the mills  is treated  in  the chemical sedimentation tank after
     removal of their surface active agents in a foam separation tank, the dosing
     rate of the coagulant can be reduced by some 30% compared with the amount
     required when the waste was directly treated in a chemical sedimentation tank.
iii)  Part of the coagulant "Activated Diatom Earth"  to be dosed into the defoamed
     waste can be replaced with an inexpensive metal salt (a mixture of aluminum
     sulfate and ferric sulfate available on market at a cost of about ¥10 per kg
     under the trade mark of MICS).
     So long as the ratio of the "Activated Diatom Earth" to  MICS is 3 :  1  or less,
     there is no problem in dewatering or  in making filter agent either.
iv)  The optimal pH value at which the Activated Diatom Earth and MICS are to be
     reacted upon the waste is in the range of pH 4.0 to 4.5.
                                     480

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     For this reason, sulfuric acid is required for pH control of the waste prior to
     add these coagulants.
     In the stage of flocculation, however, dose of lime for controlling the pH value
     at 7 to  8 is better improving the floe-settling characteristics in the sedimenta-
     tion tank.
     Partial return of the  settled sludge into the flush mixing tank is  effective for
     the solid/liquid separation in the sedimentation tank.
v)   It is desirable to set the surface loading of the sedimentation tank at 40m3/m2.d.
     or below, and the detention time at more than 2 hrs. or more.
vi)   Liquid-state surface active agent separated  from the foam separation tank is
     brought  in contact with the settled sludge for a long period,  and then almost
     entirely is removed as adsorbed into diatomaceous earth.

     Fig. 4.5  shows a flow sheet of the joint pretreatment facility for the waste,
which has been  in operation since March this year.
     A part of the operation result are as shown in Table  4.2. Although the results
of the treatment  of actual wastes containing various kinds of dyestuffs are worse
than  those of the independent treatment of each dyestuff, but  the results  are still
encouraging.
                                    -  481  -

-------
Table 4.1   COD Removals and Color Reduction Effects by Dosing Coagulant
           "Activated Diatom Earth" 0.5 g/L or 1.0 g/L
~"~-\^^ Items
Dyes ^"~^--^^
(Disperse dyes) (0.1 g/C)
Resoline blue BR
Kayalon fast blue RD GGF
Kayalon polyester turg. blue
(Acid dyes) (0.1 g/C)
Lanasyn blue GL
Cidalan brill red RL
Suminol leveling red 3B
Kayanol milling red RS
(Naphtol dyes) (0.1 g/C)
TD black 10G-2S
(Direct dyes) (0.1 g/C)
Dialuminous blue GF
(Vat dyes) (0.1 g/C)
Indanthren red FBB
(Reaction dyes) (0.1 g/C)
Mikacion rubine BS
(Basic dyes) (0.1 g/G)
Aizen cathilon red GTLH
CODMn
(PPM)

80.8
46.6
54.3

77.4
75.5
41.6
24.7

65.1

25.4

54.3

39.8

65.3
0.5 g/C
CODMn
removal
(%)
67.3
63.7
70.7

91.1
69.4
73.1
88.3

84.8

76.8

82.9

51.7

40.6
Color
reduction
(%)
100
94.9
100

100
100
92.4
100

100

79.5

100

88.6

90.5
1.0 g/C
CODMn
removal
(%)
84.9
65.7
78.6

92.5
70.4
78.4
95.6

86.6

87.8

84.0

57.0

52.0
Color
reduction
(%)
100
97.2
100

100
100
97.1
100

100

100

100

88.9

95.1
                              -  482  -

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                                 Table 4.2   A Part of Operational Data of Dying Waste Treatment Facility, Sabae City, Fukui Pref.
~~"~~~~ — ~__ c Date
i«. ^ ^s**^
Temperature (°C)
pH
Transparency (cm)
CODMn (mg/fi)
BOD (mg/2)
Sus. solids (mg/C)
400 m/z absorbance
Inf.
Eff.
Inf.
Eff.
Inf.
Eff.
Inf.
Eff.
Inf.
Eff.
Inf.
Eff.
Inf.
Eff.
Mar. 8
12:00
35.0
33.5
7.50
6.40
17
>30
127
63.6
99
53
13.3
12.4
0.223
0.107
Mar. 8
14:00
34.5
33.0
7.50
6.42
17
>30
117
58.6
101
45
15.2
7.2
0.212
0.082
Mar. 8
16:00
35.0
33.0
7.45
6.52
16
>30
117
58.6
112
48
16.2
6.2
0.232
0.082
Mar. 10
13:30
35.0
33.0
7.50
6.67
17
>30
116
39.7
102
38
20.4
5.2
0.252
0.051
Mar. 10
15:30
35.0
33.0
7.80
6.80
17
>30
131
43.8
118
35
21.6
3.2
0.265
0.051
Mar. 13
13:00
32.0
33.0
7.68
6.82
17
>30
140
52.4
109
39
20.0
6.4
0.235
0.066
Mar. 14
11:30
35.0
34.5
7.6
6.75
16
>30
128
65.3
112
54
26.3
23.4
0.264
0.097
Mar. 14
13:30
36.0
34.5
7.73
6.85
15
>30
143
58.5
118
55
24.7
17.2
0.294
0.086
Mar. 14
15:30
34.0
34.0
7.65
6.90
12.5
>30
156
65.3
131
57
20.3
17.2
0.361
0.081
CO

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                           lizjj

Wakura &
Notoshima
Yamatoda
lizuka
lida
Layer
Depth (m)
20-60
10-20
100-400
10-60
Volume of Deposits
(x 106 mj)
340
100
4,800
25
                               .Kyoto
                                    Nagoya    Tokyo
                              saka
Fig. 4.1  Destribution of Diatom Earth Raw Materials in Noto Peninsula, Ishikawa Prefecture
                                          484  -

-------
00
Cn

Scrubber [- 	

'
Line
Mixing Tank
i i
Water J 	 '




Settling
Tank

                                                                                                                                                     Discharge
                                                                                           Coagulant
                                                                                          "Activated Diatom Earth"
                                                  Fig. 4.2  Manufacturing Flow Diagram of Coagulant "Activated  Diatom Earth"

-------
   100 r-
I  50
o
3
T3
O
u
                            -•—.—  Acid Dyes (Suminol Leveling Reb 3B)

                            -o —o—  Base Dyes (Aizen Cathilon Red K-GLH)

                            -x—x— Disperse Dyes (Resloine Blue BR)
Each Dve Solution Containes
0.25 g/£ of Dyestaff
                                    7

                                   PH
 10
13
       Fig. 4.3  Relationship between Color  Reduction Effects and

                pH Variation


               (Coagulant "Activated Diatom Ecarth"Dose 1  g/8 _)
                                - 486  -

-------
-PS.
00
                         Sludge Hopper
                      Sludge Preliminary
                      Drying
Sludges from
Dying Waste
Treatment Facilities
                              Oryeir
                                                    Blower
                                                     Soda Ash
                                                     or Sodium
                                                     'Chloride
                    Fig. 4.4  ManuiactuTrng iRhw QSiagrain xtf Diatom Earth Filter Aid from Sludges from Dying Waste Treatment Facilities

-------

.......... J
Sulferic
Arid


,,,_ Surface Active ™

Diatom
larth

Lime
(
ush Flocculation Sedimentation „. ,
EquJization Pumps •" ™%n]c l •" Mixing Tank ~ 'lank ~.—.B*
lanK | 	 1

Foaming
Liq uo r
Sewer Pipes (
CO li .1 i| ,
m ....
Surface Active
Agent and
Sludge Mixing
, 	 . . , , . T-i n I-
Dying Dying
Mill Mill
F

Thickener
Sludge Return

Supernatant
Sludge Vacuum To Diatom Earth Filter Aid
Filler *" Manufacturing Factory
Fig. 4.5  Flow Diagram of Dying Mills Waste Treatment Plant, Sabae City, Fukui Prefecture

-------
CHAPTER 5.   IMPROVEMENT OF EFFLUENT QUALITY OF BISAI
              DISTRICT SEWAGE TREATMENT PLANT IN AICHI
              PREFECTURE
5.1  Quality of Sewage and Present State of the Sewage Treatment Plant	490
5.2  Installation of Pilot Plant	491
5.3  Installation of Pretreatment Facilities	491
5.4  Results of Laboratory and Pilot Plant Experiments	492
5.5  The Modification of Sewage Treatment Plant	494
5.6  Experiments and Studies of the Future	494
                                  489

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5.   IMPROVEMENT OF EFFLUENT QUALITY OF BISAI  DISTRICT SEWAGE
     TREATMENT PLANT IN AICHI PREFECTURE
5.1  QUALITY OF SEWAGE AND PRESENT STATE OF THE SEWAGE TREAT-
     MENT PLANT
     Bisai City, Inchinomiya City  and Kisogawa-cho,  in Aichi Pref. are alive with
one  hundred and odd  factories processing raw wool, dying and finishing woolen
textiles,  the wastes coming  from  which have been treated  at the Bisai  District
Sewage Treatment Plant designed solely for industrial wastes treatment.
     In  the district, there are little factories which are equipped with a  through
production system handling  all the way from raw wool processing to the finishing
of woolen fabrics.
     The production system is roughly classified into four  processes: raw wool
processing, dying, weaving and finishing.
     Of them, weaving factories do not deliver industrial wastes, but all the others
vomit wastes peculiar to respective processes.
     The factories with raw wool  process deliver wastes containing a great deal of
organic  substance and  grease.  The factories with dying process discharges wastes
of residual dyes,  inorganic salts (mainly sodium sulfate, soldium sulfide, etc.) and
high temperature waste water  containing various kinds  of surface active agents.
The  factories  with  finishing process  discharge waste  water containing unrecover-
able  short fibers and various surface active agents.
     The quality  of raw sewage running  into the Bisai Sewage Treatment Plant is
shown in Table 5.1.
     The raw  sewage is almost neutral,  but is high in  temperature and contains
reducing materials and greases.
     The  concentration of suspended solids is not  so high, but most is occupied
by short fibers which are hard to settle in the sedimentation tank.
     The reducing materials are mainly composed of sulfides.
     This is because in addition  to  sodium sulfide contained in sewage, sodium
sulfate is reduced into  sulfides biochemically in the  sewer pipes. The Public Works
Research Institute of the Ministry of Construction  has once  conducted an experi-
ment on the reduction of sulfate ions of this waste  water into sulfides.
     The  results  are as shown  in  Fig. 5.1. The test temperature was  25 to 30°C.
     The  present facilities of  the  Bisai District Sewage  Treatment Plant include
three circular  primary sedimentation tanks,  three  four-path rectangular  aeration
tanks, nine  rectangular final settling  tanks, one rectangular thickener, two vacuum
filters, and a sludge incinerate A.
     This sewage treatment plant  is  located next to the Ichinomiya Seibu Sewage
Treatment Plant,  and some of the  facilities are used  common to both plants.
     A  plan view of the  Bisai District Sewage  Treatment Plant is shown in Fig.
5.2.
     When designing this plant, the effects of short wool  fibers,  greases and oils,
reducing materials  and various surface  active  agents on the process were  not
evaluated thoroughly. In addition,  sludge production rate and thickening rate were
                                     490 -

-------
misevaluated.
     Design capacity  of the existing facilities is  70,000 m3/d.  On one  occasion
when the production of woolen products increased, the influent into the sewage
plant reached  as large as 140,000 m3/d. At  present, the influent  is in the range of
80,000  to  100,000  m3/d.  as  a  result  of  strong save-water  campaign against
factories.
     Even this, however, still surpasses the planned capacity of the plant.
     While the effluent  quality standard applied to this sewage treatment plant is
20 mg/1 or less in BOD, effluent of the Plant is in the range of 60 to 80 mg/1.
     At the request of the Sewage Management Authority, the Water Quality Con-
trol  Division of the Public Works Research Institute, Ministry of Construction, is
extending technical assistance in the improvement of effluent quality and modi-
fication of the plant facilities.

5.2  INSTALLATION OF PILOT PLANT
     The  request of the Sewage Management Authority for  the improvement of
effluent  quality and modification  of  facilities presupposed  increasing the  design
capacity up to 100,000 m3/d. and reducing BOD of effluent to 20 mg/1. without
expanding the existing site area.
     In fact, the  lots adjoining to  the plant are  hard to purchase, and the expan-
sion  of  the  right-of-ways  for  the plant  from  the present  scale is still  more
difficult.
     The  open space available in the premises is very limited. For this reason, it
was  judged difficult to  add up the primary sedimentation  tanks, aeration  tanks
and  final settling tanks.
     In order  to manage a  proposed flow  of  100,000 m3/d. with the existing
facilities, the design values should be reset as follows.
     Average overflow rate of the primary sedimentation tank: 27.2 m3/m2.d.
     Average aeration time:  3.85 hrs.
     Detention time of  sewage  in  the aeration  tank  with sludge return ratio at
30%: 2.95 hrs.
     Average overflow rate of final  settling tank (with sludge return ratio  at 30%):
35.3 m3/m2.d.
     Prior to  mapping out modification plans for sewage treatment facilities, vari-
ous  investigations were  required,  but it was difficult to utilize part of the existing
facilities for testing purposes.
     Accordingly, it was decided to install a pilot plant copying  the existing plant
to a scale of 1/1,000.
     The  pliot plant,  was designed  to simulate the changes of that  in the  full-scale
plant.

5.3  INSTALLATION OF PRETREATMENT FACILITIES
     In view of the limited capacity of the sewage treatment plant and  the need
to improve  the effluent quality without expanding its facilities, it was also needed
to request the factories  to moderate their  waste  discharge into  the sewer.
                                  -  491 -

-------
    The requests were as follows:
i)    Each factory to  make  every effort to  limit its daily discharge not to exceed
     the total factory discharge of  79,000 m3/d.  set by the Sewage Management
     Authority.
ii)   Each raw wool processing factory to install a pretreatment facility to remove
     high concentration of n-hexane extracts  contained in its effluent to 30 mg/1.
     or less.
iii)   Each of those raw wool processing and dying factories which discharge  waste
     water of 40°C or higher to install a heat exchanger to recover heat in order
     to decrease wastewater temperature before discharge into the sewer to  lower
     than 40° C.
iv)   Each chromic dye-using factory to install a pretreatment facility to remove
     chromium and limit the  chromium  content  in effluent before discharge  to
     lower than 0.5 mg/1.
     If possible,  such  chromium removal facility should be used common  to  all
     chromic dye-using factories.
v)   Each finishing factory  to  install a micro  screen of 4 x  4 mm meshes in order
     to reduce the discharge of short wool fibers.
vi)   Those factories which  discharge waste water of more that 1,000  m3/d  to
     install a storage tank for the purpose of equalizing effluent.
     At present, the equalization of effluent  is undertaken by two storage tanks
     (7,000 m3 and 5,000 m3) and sewer pipes (8,000 m3) (20,000 m3 in total).
     If the factory with more  than I,000m3/d of waste water is equipped  with a
     storage tank the influent  of the sewage  treatment plant will be  kept almost
     constant all the day.

5.4  RESULTS OF LABORATORY AND PILOT PLANT EXPERIMENTS
     Both laboratory  study  and pilot plant  experiments are still in progress. The
findings obtained so far are as follows:
i)    Chemical flocculation  to  remove  reducing  materials, oils  and  greases and
     short  wool fibers  in the primary sedimentation tank  has been studied both
     on a laboratory scale and pilot plant scale.
     It is found  that the use of aluminum sulfate and lime in combination is most
     effective.
     The required dose is 200  to 300 mg/1. of A12(SO4)3  and  100 to  120 mg/1.
     of Ca(OH)2. In this  process, the oils and greases in the waste water can  be
     removed  70  to 80%  in terms  of n-hexane extracts. Also, the reducing  mate-
     rials can be removed more than 60%  in terms of  iodine demands. In addi-
     tion, short wool fibers can be removed  efficiently.  The sludge volume  devel-
     oped from the process is  170  to  220 mg/1 in terms of suspended solids, and
     the under flow concentration of the sedimentation tank is less than 0.5%
     According to the  cylinder test, the thickening of this  sludge is very  poor;
     even with a 24  hrs  thickening, the reduction  of the  sludge volume is only
                                     492

-------
     about 50%.
ii)   As against  the overflow rate of 27.2 m3/m2  -d. (max. 31.7 m3/m2 .d.), the
     plain sedimentation gave suspended solids removal of approx. 80 mg/1 or some
     47%.
     The withdrawn sludge concentration was approx. 0.5%.
     According to the sludge  thickening  test by cylinder, the sludge  volume was
     reduced to  some one-third in about 18 hrs of thickening time.
iii)   Effluent of plain sedimentation was treated by activated sludge process with an
     average aeration  time of 3.83  hrs.
     In this case, the ratio of sludge return from the final settling tank was 25%.
     The concentration of return sludge  was very high enough to maintain MLSS
     in the aeration tank at level of 3,000 to 4,000 mg/1.
     As a result, effluent BOD was 16 to 20  mg/1  with  MLSS above 3,000 mg/1,
     BOD loading lower than 0.376 kg/kg.  MLSS.d. and  with the air supply more
     than 9 times the influent.
     In this case, SVI of the activated sludge was approx. 100. DO in  the aeration
     tank was able to be kept at  2 mg/1 all the time.
     The results of molecular  graduation of influent and  effluent by  Sephadex
     G15 are shown in Fige. 5.3  and 5.4.
iv)   Sometimes,  the  influent carries wastes  with  a odor of naphtol. In such  a
     case, DO in the aeration tank is reduced almost naught, and BOD of effluent
     becomes  higher than 20 mg/1.
     It remains  uncertain  what  air flow rate can  keep DO concentration in the
     aeration tank above 0.5 mg/1.
     Molecular graducation by Sephadex G15 of influent and effluent in these cases
     is as shown in Figs. 5.5 and 5.6.
v)   The influent shown in Fig.  5.5 is richer  in low molecular materials of frac-
     tion number 28 or above than that shown in Fig. 5.3.
     High molecular weight materials are less compared with Fig. 5.3.
     On  the other hand, the influent  shown  in Fig.  5.3  is rich in high  molecular
     weight materials  of  more than 1,500  in molecular weight and  in colloidal
     materials.
vi)   Fig. 5.4 indicates that organic removal was significant in the process.
     The influent shown in Fig.  5.3 contained a great amount of high  molecular
     weight meterials and  colloidal materials,  but did not affect to the  treatment
     at all.
     The peak of the ultea-violet absorbance curve  for the effluent shown in Fig.
     5.6  was shifted toward the lower  molecualr weight side as compared with the
     effluent in  Fig.  5.4.  This  is inferred  to be ascribable to the fact that the
     dissolved oxygen  might have been in deficit in the  activated  sludge process.
vii)  Plastic diffuser were used for the pilot plant. The oxygen absorption efficiency
     of this plastic diffuser was  6.1%  when the water depth was 2.0 m  above the
     diffuser.
                                   - 493

-------
    The disc  diffuser now in operation  creates some 3% of oxygen absorption
    efficiency  when  the  water depth is  3 m.  This  low performance is further
    aggravated by  the  colgging of the pores with grease and  short  wool  fibers
    contained in the  sewage.
    It is therefore  urgently needed to replace the diffuser with one which  is not
    affected by grease  and short wool fibers and with which high oxygen absorp-
    tion efficiency  can  be attained.
viii) The oxygen consumption rate, kr.  of the  activated sludge was measured at
    four points in  the  aeration tank. The results were  37.0, 28.2, 20.9 and  15.9
    mgO2 /gr/hr.
    The selection of  diffuser and determination of air supply rate are  to be made
    according to the  above results, and in  consideration of the case where sewage
    of  low oxygen absorption efficiency  can run into the system on some occa-
    sions.
ix)  There  were lots  of scum and floating matters  on the  surface  of the final
    Settler.
    The scum increased BOD  and  suspended solids of the effluent.

5.5 THE MODIFICATION OF SEWAGE  TREATMENT PLANT
i)   The primary sedimentation tank is  to be  modified to  carry out plain sedi-
    mentation.
    The sludge collector  is to be  modified to have  an increased collecting speed
    in order to shorten the detention time of sludge in the tank.
    The primary sedimentation tank is to be equipped  with a scum  collector. In
    order  to  improve  the  sludge  withdrawal, the valves and pipeline are to be
    modified.
ii)  The diffusers are to be replaced with a more efficient ones.
    Additional air blowers are to be installed to make up air supply.
iii)  The final settling tank is to be equipped with a scum collector. Also, an  air lift
    is to be provided  for easier withdrawal of sludge.
iv)  The sludge  thickener is to be  expanded in order to allow  more  than  18 hrs
    of  thickneing time.
    It is also to be provided with  a scum collector in the thickener.

5.6 EXPERIMENTS AND STUDIES OF THE FUTURE
i)   Preaeration will  be carried out for the purpose of increasing the grease re-
    moval by promoting dewatering of emulsified greases and oils and of increas-
    ing the removal of  reducing materials.
    The detention  time of the preaeration tank  should  be within 20 min.
ii)  Experiments for  the  determination  of the diffuser  characteristics  to be
    applied in the aeration tank will be conducted. The experiments should cover
    determination  of the oxygen  transfer efficiency and the  protection of the
    diffuser from clogging by grease.
                                  -  494 -

-------
iii)  Study  will be made to provide measures to maintain the level of dissolved
     oxygen constant in the aeration tank even when sewage of low oxygen demand
iv)  Dewatering of thickened sludge will  be studied  on presupposition that the
     sludge be incinerated, and the equipment will be selected so to meet.
v)   Odor  control  at preaeration  tank and  sludge  treatment facilities  will  be
     studied.
                                    -  495  -

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Table 5.1   Influent Quality of Bisai District Sewage Treatment Plant,
           Aichi Pref.  (February to March 1975)
~~—~^__^^ Range
Items
Sewage temperature
Transparency
or average
^^^
CO
(cm)
pH
Suspended solids
CODMn
BOD
Iodine demands
n-Hexane extracts
Total chremium
(mg/C)
(mg/C)
(mg/C)
(mg/C)
(mg/C)
(mg/C)
Range
21.0 ~ 31.5
2.2 ~ 5.7
6.6 ~ 8.4
50 -202
62.9 ~110.2
89.8 -291.6
8.3 ~ 46.4
7.6 -128.0
0.21~ 1.10
Average
27.5
3.6
7.3
129.0
88.7
181.2
28.2
70.3
0.59
                              -  496 -

-------
-P"
UD
                          •a
                          >,
                          X
                          00
§
                          3
                          00
   70-



£,60-


-------
                   Chlorine Contact Tank
                    ooo
                 ) |  Sludge Incinerator
o
-X
.*!

          "^  '     \

     Sludge ! .Thickener '
           ' \        )

     ..	/  \    /
Sludge Dematering

Building
                           I      I     I     I

                               Final Settling Tank
                                                                     T3 S
                                                                     j2 2
                                                                      cd  GO


                                                                      If
                                                                      °  I
                                                                     m £,
IT


^
r

>»
^v
Ae
^

ation
J

Tank
^
f

J
•N

V


>


V
r

>»
•N

L


y
                          Fig. 5.2  Plan of the Bisai District Sewage Treatment Plant, Aichi Prefecture

-------
  2.0
                                                 	Sample Filtrated 0.45/j Membrene
Sample Concentrated 10 times of
Above Filtrated Sewage
Fig. 5.3   Molecular Graduations of Influent, Ultra-Violet Absorbance, and Carbon and
          Nitrogen Compound Variations
                                      -  499  -

-------
     < 0.5-
=  £
O  GO
-0  O
   --
<->  z
       50-
o
h- £
                                                                  Sample Filtrated 0.45/u
                                                                  Membrane

                                                                  Sample Concentrated 10 times
                                                                  of Above Filtrated Sewage
            10
                                                                                 40
                                                                                      Fraction
                                                                                      Numbers
                                                        P5XXXSI    Total Carbon
                                                   TOC   1C
                                                                  Total Nitrogen
    Fig. 5.4   Molecular Graduation of Effluent, Ultra-Violet Absorbance, and Carbon and
              Nitrogen Compound Variations
                                           -  500

-------
  1.0-
                                                                 Sample Filtrated 0.45^
                                                                 Membrane

                                                                 Sample Concentrated 10 times
                                                                 of Above Filtrated Sewage
Fig. 5.5   Molecular Graduation of Effluent, Ultra-Violet Absorbance, and Carbon and
          Nitrogen Compound Variations
                                        -  501  -

-------
                                                              Sample Filtrated 0.45^
                                                              Membrane

                                                              Sample Concentrated 10 times
                                                              of Above Filtrated Sewage
                                                                          40   Fraction
                                                                               Numbers
Fig. 5.6  Molecular Graduation of Effluent, Ultra-Violet Absorbance, and Carbon and
         Nitrogen Compound  Variations
                                      -  502  -

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                                AGENDA

                           CINCINNATI, OHIO

                      ROBERT A. TAFT LABORATORY

                        Thursday, October 23
 8:30 am     F. M. Middleton  -  Official Opening of Conference
             Dr. T. Kubo  -  Response

 8:45 am     L. W. Lefke  -  Welcome to Cincinnati

 8:55 am     F. M. Middleton  -  Agenda Approval

 9:00 am     R. C. Brenner  -  Updated Status of Oxygen-Activated
                                 Sludge Wastewater Treatment

 9:45 am     Break

10:00 am     B. V. Salotto  -  Current Research Related to Heat
                                 Conditioning of Wastewater
                                 Sludge

10:30 am     R. A. Olexsey  -  EPA's Research Program in Sewage
                                 Sludge Combustion

11:00 am     R. I. Field  -  Urban Stormwater Management and
                               Technology in the United
                               States  -  An Overview

12:00 noon   Lunch

 1:30 pm     J. J. Westrick  -  Activated Carbon for Municipal
                                  Wastewater Treatment

 2:15 pm     J. Ciancia  -  New Industrial Wastewater Separation
                              Processes Developed Under the
                              EPA Research Programs

 3:00 pm     Break

 3:15 pm     J. F. Roesler  -  Status of Instrumentation and
                                 Automation for Control of
                                 Wastewater Treatment Plants

 4:00 pm     J. N. English  -  Research Required to Establish
                                 Confidence in the Potable
                                 Reuse of Wastewater

 4:30 pm     J. J. Convery  -  Summary and Comments

 5:00 pm     F. M. Middleton  -  Closing and Announcements

                             -  503  -

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              UPDATED STATUS OF OXYGEN-ACTIVATED SLUDGE WASTEWATER TREATMENT
                                       R.  C.  Brenner
                           U.  S.  Environmental Protection Agency
                        Municipal Environmental Research Laboratory
                                  Cincinnati,  Ohio 45268
                                         ABSTRACT

     The oxygen-activated sludge wastewater treatment process continues to enjoy vigorous
growth in the United States.   Recently,  new markets for oxygenation technology have emerged
in Japan, Europe,  and the greater North  American continent.   As of June 1976, 50 oxygen-
ation installations were in operation.   An additional 66 oxygen plants were under construc-
tion and designs were in progress for another 41.  The combined design flow of these 157
known commitments  to the use of oxygen exceeds 5.8 bgd (254  cu m/sec).  Approximately
one-half of the operating installations  are industrial wastewater applications.

     The Union Carbide Corporation,  from its vantage point of first entry into the field,
has collected the  major share of the oxygen market to date with its covered reactor UNOX
system.   The only other available covered reactor oxygenation system is sold by Air
Products and Chemicals, Inc.  under the trade name OASES.   An open reactor oxygen-activated
sludge option (MAROX) employing ultra fine bubble rotating active diffusers has recently
been developed by the FMC Corporation.   A large-scale demonstration project evaluating
this MAROX system is currently underway  at Metropolitan Denver's main wastewater treatment
plant.  The project is a joint effort of the local government, FMC, and the federal
government.
               INTRODUCTION

     In the past eight years,  the use of
oxygen gas in the activated sludge process
has evolved from a level of primarily aca-
demic interest to a point of broad appli-
cation and implementation.   A large and
rapidly growing number of oxygen-activated
sludge plants are in operation in North
America and Japan.  Several plants will soon
be operational in Europe.  Included among
the operating facilities are installations
treating process wastewaters from six major
industrial categories.  By 1980,  it is pro-
jected that construction will  be  completed
on approximately 150 oxygen systems with a
combined hydraulic capacity between 5 and 6
bgd (219 to 263 cu m/sec).

     Beginning with the initial research
project conducted by Union Carbide at
Batavia, New York, in 1968 and 1969 (1),
the development and refinement of oxygen-
ation technology has been more rapid than
normally associated with wastewater treat-
ment processes.  Design engineers today can
select from several oxygen dissolution con-
cepts including both covered and open reac-
tor alternatives.  The covered reactor UNOX
and OASES systems are available with either
surface aerators or submerged turbines.
The surface aerator option has become the
standard covered reactor design except in
cases where unusually deep tanks are speci-
fied.  FMC markets two versions of its open
reactor MAROX system, one utilizing rotating
active diffusers (RAD's), the other fixed
active diffusers (FAD's).  At this time, the
second generation RAD design appears to be
a significant cost-effective improvement
compared to the original FAD design.  In the
near future, a fourth company, AIRCO
Cryoplants, is expected to start actively
competing in the oxygenation field.  AIRCO
has named its latest development the F30
system, which stands for forced free fall
                                            504

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oxygenation.  The principal components of
the F30 system are a gas-tight drop-in
concrete hood, an axial flow pump, a nozzle,
and an oxygen enriched waterfall zone.

     The purposes of this paper are three-
fold:

     1.   To provide an updated status report
on the number and type of oxygen-activated
sludge facilities in operation, under con-
struction, and being designed.

     2.   To describe in detail the latest
EPA supported oxygenation research and
demonstration project, an evaluation of the
RAD version of the open reactor MAROX system
being carried out at the Metropolitan Denver,
Colorado Sewage Treatment Plant.

     3.   To summarize design, operating,
and performance information for several
on-line oxygen wastewater treatment systems.

         STATUS REPORT   JUNE 1976

     A complete listing of the 50 oxygen-
activated plants that were in operation as
of June 1976 is presented in Appendix A.
The 66 oxygenation plants under construc-
tion on the same date are listed in Appen-
dix B.  An additional 41 oxygenation plants
were in various stages of design during
June 1976; these plants are listed in Appen-
dix C.  Besides these 157 known commitments
to oxygen use, proposals have been made to
numerous other potential municipal and
industrial customers by the several oxygen
proprietary firms.  These potential cus-
tomers are not included in Appendix C be-
cause final decisions on process selection
have not yet been made.  It should be under-
stood from the above comments that the
status of oxygen implementation is in a
state of flux and that the three lists given
in the Appendices will be out of date within
several months.

     All three appendices provide design
flow and oxygen supply data (where known)
for each plant location listed, as well as
identifying the wastewater application.
Multiple oxygen process applications, such
as carbonaceous organics removal plus nit-
rification, aerobic digestion, ozonation,
etc., are also noted where applicable.  In
addition, Appendices A and B include infor-
mation on the oxygen dissolution and oxygen
supply systems selected.  This latter
information is not given in Appendix C
because these plants have either not yet
been bid or litigation has delayed awarding
of contracts to specific oxygen system
suppliers.

     Perusal of Appendix C reveals that no
industrial wastewater applications are shown
in the "plants being designed" list.  This
omission is not intended to indicate that
no industrial plants were in the design
phase as of June 1976, but rather that the
identity of such plants is confidential
proprietary information until after equip-
ment purchase contracts are awarded.

     Data on the number of plants, design
flows, and oxygen supply capacities have
been extracted from Appendices A, B, and C
and condensed in Table 1.  The same infor-
mation is presented in Table 2 for United
States oxygen plants only.  These two tables
indicate that as of June 1976 only about 12
percent of the firm planned oxygen design
flow capacity was actually completed and
in operation.  On-line capacity is expected
to increase 7-8 times, however, in the next
4-5 years.  Approximately 25 percent of the
oxygen installations included in the Table  1
totals are treating or will treat industrial
process wastewaters.  Excluding the Japanese
plants for which oxygen supply data were
unavailable to the writer, the design oxygen
supply capacity averages 3.07 tons/mil gal
of design flow (7.4 x 10   metric ton/cu m)
for the industrial applications compared to
1.34 tons/mil gal of design flow (3.2 x 10~4
metric ton/cu m) for the municipal appli-
cations .

     A breakdown of the 157 known operating
and planned oxygen installations by country
is given in Table 3,  Eighty-five percent
of these installations are or will be lo-
cated in the United States and 11 percent
in Japan.  The remaining 4 percent are
divided among seven other countries with
one plant each.

     The detailed information provided in
Appendices A and B on oxygen dissolution
and oxygen generation systems is summarized
in Tables 4 and 5, respectively.  The
dominance of Union Carbide in the oxygen
dissolution market to date is evident:  of
the 116 oxygen installations that were
operational or under construction in June
1976, a UNOX system was selected for 87
percent.  In most but not all cases, the
vendor supplying the oxygen dissolution
equipment was also awarded the oxygen
                                            505

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                    TABLE 1.   WORLDWIDE OXYGEN PLANT STATUS   JUNE 1976
Parameter
No. of Plants
Municipal
Industrial
Total
Design Flow (mgd)*
Municipal
Industrial
Total
02 Supply Capacity^ (tons/day)*
Municipal
Industrial
Total
Operating
Plants
26
24
50
584.5
135.5
720.0
477.7
389
866.7
Plants
Under
Construction
49
17
66
2302
191.5
3126.5
462.5
3589.0
Plants
Being
Designed
41
41
2647.3
3794
3794
Total
116
41
157
5533.8
327.0
5860.8
7398.2
851.5
8249.7
*1 mgd =•= 0.044 cu m/sec
tOxygen supply figures shown do not include data for Japanese plants; these data were
 unavailable to the writer.
+1 ton/day = 0.907 metric ton/day
                       TABLE 2.   USA OXYGEN PLANT STATUS - JUNE 1976
Parameter
No. of Plants
Municipal
Industrial
Total
Design Flow (mgd)*
Municipal
Industrial
Total
02 Supply Capacity (tons/day) t
Municipal
Industrial
Total
Operating
Plants
21
14
35
570.3
94.3
664.6
467.7
389
856,7
Plants
Under
Construction
46
11
57
2172.8
166.8
2944.5
383.8
3328.3
Plants
Being
Designed
41
41
2647.3
3794
3794
Total
108
25
133
5390.4
261.1
7206.2
772.8
7979.0
*1 mgd = 0.044 cu m/sec
tl ton/day = 0.907 metric ton/day
               TABLE 3.   BREAKDOWN OF OXYGEN PLANTS BY COUNTRY - JUNE 1976
Country
1.
2.
3.
4.
5.
6.
7.
8.
9.
USA
Japan
Canada
Mexico
England
Germany
Denmark
Switzerland
Belgium

Operating
35
14
1
No. of Plants
Under
Construction
57
3
1
1
1
1
1
1

Being
Designed Total
41 133
17
1
1
1
1
1
1
1
                  Total
50
66
41
                                                                          157
                                           506

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supply system contract,  The preponderance
of surface aerators over submerged turbines
in covered reactor systems is illustrated
in Table 4 and is attributed to the lower
overall costs and maintenance requirements
of the aerator option.  Surface aerators are
being or will be used in 93 percent of the
covered reactor systems with specified
dissolution equipment, submerged turbines in
6 percent, and a combination of both in one
system.  Plants employing submerged tur-
bines have deep aeration tanks, typically
greater than 20 ft (6.1 m), and tend to be
larger than 100 mgd (4.4 cu m/sec) in size.
Conversely, the average design flow of the
103 surface aerator systems is only about
18 mgd (0.8 cu m/sec).

     Cryogenic oxygen gas generators are
sold by several firms in the United States,
whereas Union Carbide is the only known USA
manufacturer of pressure swing adsorption
(PSA) oxygen gas generators.  The break-
even range determined by Union Carbide for
these two oxygen supply systems is approx-
imately 20-25 tons/day (18-23 metric tons/
day).  Below this range, it is more cost
effective to use PSA generators; above this
range, cryogenic generators are more cost
effective.  Other manufacturers have
developed mini-cryogenic oxygen generators
to compete for the lower tonnage plants,
On-site cryogenic or PSA gas generation
was selected for 80 percent of the 99
oxygen-activated sludge plants with defined
methods of oxygen supply, as of June 1976.
The average capacities for these 79 supply
systems are 92 tons/day (83 metric tons/day)
for the cryogenic units and 16,2 tons/day
(14.8 metric tons/day) for the PSA units.

     Pipeline transport of off-site gen-
erated oxygen gas to an oxygenation waste-
water treatment plant can be an economical
choice of oxygen supply if the logistics
are reasonable and if the off-site facility
(e.g., a steel production plant) has extra
generation capacity.   This method of oxygen
supply accounts for 9 percent of the defined
supply systems and 6 percent of the June
1976 "operating" and "under construction"
capacity,  On-site storage and vaporization of
trucked-in liquid oxygen, because of its
high unit cost, is generally confined to
requirements of 5 tons/day (4,5 metric tons/
day), or less.  The oxygen consumption of
the 11 such systems documented in Table 5 is
expected to average 2.9 tons/day (2.6 metric
tons/day); this amounts to only 0.7 percent
of the defined oxygen supply capacity.
                  TABLE 4,  SUMMARY OF OXYGEN DISSOLUTION SYSTEM VENDORS,
                  	TYPES, AND DESIGN FLOWS - JUNE 1976	
                   Parameter
    Operating
     Plants
   Plants
   Under
Construction
Total
02 Dissolution System Vendor (No.)
   UNOX - Covered Reactor44
   OASES   Covered Reactor                             4
   MAROX   Open Reactor                                2
      Total                                           50

02 Dissolution System Type (No.)
   Covered - Surface Aerators44
   Covered - Submerged Turbines                        4
   Covered - Combination of Aerators and Turbines         0
   Open   Rotating Active Diffusers                    2
   Open   Fixed Active Diffusers                       0
      Total                                           50

02 Dissolution System Design Flow (mgd)*
   Covered - Surface Aerators                        286
   Covered - Submerged Turbines                      423.8
   Covered - Combination of Aerators and Turbines         0
   Open - Rotating Active Diffusers                   10.2
   Open - Fixed Active Diffusers                       0
      Total                                          720.0
                      57
                       6
                       3
                      66


                      59
                       3
                       It
                       2
                       1
                      66
                    1526
                     345
                     600f
                      21.5
                       1
                    2493.5
                  101
                   10
                 	5_
                  116
                  103
                    7
                    1
                    4
                 	1_
                  116
*1 mgd * 0.044 cu m/sec
tThe oxygen dissolution system for Detroit's second-phase construction consists of sub-
 merged turbines in the lead stages and surface aerators in the rear stages.
                                            507

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                         TABLE 5.  SUMMARY OF OXYGEN SUPPLY SYSTEM
                             TYPES AND CAPACITIES - JUNE 1976
                   Parameter
                  Operating
                   Plants
                           Plants
                            Under
                        Construction
                                                                                  Total
02 Supply System Type (No.)
   On-Site Cryogenic Generation
   On-Site PSA Generation
   On-Site Liquid Storage and Vaporization
   Off-Site Pipeline Transport
   Unknown*
      Total
                      7
                     15
                      9
                      5
                     14
                     50
                             31
                             26
                              2
                              4
                              3
                             66
                               38
                               41
                               11
                                9
                               17
                                                  116
02 Supply System Capacity (tons/day) t
On-Site Cryogenic Generation
On-Site PSA Generation
On-Site Liquid Storage and Vaporization
Off-Site Pipeline Transport
Total
407
254
27.8
178
866.8
3086.8
413.5
4.5
84.2
3589.0
3493.8
667.5
32.3
262.2
4455.8
*Data unavailable for Japanese oxygen supply systems
tl ton/day * 0.907 metric ton/day
     Oxygen plants treating or scheduled to
treat industrial wastewaters are broken down
by industrial application in Table 6.  Eight
major categories are represented in the
"operating" and "under construction" clas-
sifications.  The pulp and paper industry
leads the list:  nearly one-half of the total
plants and over three-fourths of the total
design flow.  The next most frequent users
to date have been the  petrochemical and
chemicals industries.  Inasmuch as oxygena-
tion technology is well suited to satisfying
the high oxygen demand associated with many
industrial wastewaters, continuing rapid
growth in the oxygen industrial market is
anticipated for years to come.
                  DESCRIPTION OF SECOND GENERATION FMC
                   OPEN REACTOR OXYGEN SYSTEM (MAROX)

                    The covered reactor oxygen system,
              including both the surface aerator and sub-
              merged turbine alternatives,, has been de-
              scribed previously in the Proceedings of the
              Second U.S.-Japan Conference on Sewage
              Treatment Technology (2) and elsewhere (3).
              A description of the first generation fixed
              active diffuser (FAD)  version of the open
              reactor oxygenation system was also provided
              in these documents.  It is not deemed nec-
              essary to reiterate those descriptions here;
              however, certain characteristics of the
              covered reactor systems and the FAD open
                           TABLE 6.   BREAKDOWN OF OXYGEN PLANTS
                                 BY  INDUSTRIAL APPLICATION
Operating
Plants
Industrial
Application
1. Chemicals
2. Dyestuffs
3. Food Processing
4. Petrochemical
5. Pharmaceutical
6. Pulp § Paper
7. Steel
8. Synthetic Rubber
No.
of
Plants
4
0
1
5
2
11
0
1
Design
Flow
(mgd) *
10.9
0
1
9.9
1.7
111.2
0
0.8
Plants
Under
Construction
No.
of
Plants
3
1
1
3
0
8
1
0
Design
Flow
(mgd) *
15.2
3.1
1.8
15.0
0
142.7
13.7
0
Total
No.
of
Plants
7
1
2
8
2
19
1
1
Design
Flow
(mgd) *
26.1
3.1
2.8
24.9
1.7
253.9
13.7
0.8
           Total
24
135.5
17
191.5
41
327.2
 •1 mgd = 0.044 cu m/sec
                                            508

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reactor system are compared with the second
generation open reactor FMC option, de-
scribed below.

     A section view of the key element (the
rotating active diffuser  (RAD)) of the second
generation FMC system is  shown in Figure 1.
As indicated, the basic RAD consists of a
7-ft (2.1-m) diameter submerged rotating
plate mounted to the bottom of a 6 5/8-inch
(16.8-cm) diameter hollow shaft approximate-
ly 3 ft (0.9 m) above the aeration tank
floor.   A 7 1/2-inch (19.1-cm) wide ceramic
diffusion medium is inserted into preformed
openings top and bottom around the  periphery
of the  plate, forming two circular  diffusion
bands parallel to the outer tapered edge.
Approximate 28-inch (71-cm) diameter radial
impellers mounted to the top and  bottom of
the plate provide essential mixing  of oxygen,
substrate, and biomass.  An optional sur-
face impeller can be installed to aid in
foam breakup, if desired.  The relatively
low design rotational velocity of 75-85 rpm
is achieved with a constant speed motor and
an appropriate gear reduction unit.  The
composite submerged assembly is illustrated
in a cutaway perspective view in  Figure 2.
                                      INTERFACE
                                    FMC—[-OTHERS
               STANDARD
                RAILING
                              FLEXIBLE HOSE
                 ROTATING GAS  SEAL
                     II     MOTOR
                     A	*    *
h-GAS SUPPLY LINE
  STANCHION
  GEAR REDUCER =
                                             WALKWAY AND TOP OF COPING
                                           WATER LEVEL
                                            SURFACE IMPELLER


                                           6 5/8" DIA.
                                          HOLLOW SHAFT
                                              MIXING  IMPELLERS
                                                       DIFFUSION
                                                       MEDIUM
                                  7'-0" DIA.
                                              TANK FLOOR^
                    . °      D.    D     i .    j     O  a   i

                f> . • ° •• O '. t>  .  t>   - P  '  _£.  •  -  *    .  ° .
          Figure 1.  Section view of rotating active diffuser and  drive assembly.
         (Printed, with modifications,  through the courtesy of the FMC Corporation.)
                                         509

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      MIXING
     IMPELLERS
  (TOP AND BOTTOM)
 DIFFUSION
  MEDIUM
(TOP AND BOTTOM)
      Figure  2.   Perspective view  of
    submerged rotating  active  diffuser
  showing  gas flow  and  bubble  formation.
 (Reprinted,  with modifications, through
  the  courtesy of the FMC  Corporation.)(4)
     A functional flow diagram for a typical
MAROX system employing RAD's for oxygen
transfer is presented in Figure 3.  The
primary oxygen supply (shown as a cryogenic
generator) is supplemented by a liquid
oxygen reserve supply and accompanying
vaporizer.  With a cryogenic generator,
unlike a PSA generator,  losses occurring
from the liquid oxygen backup tank, either
through usage or evaporation, can be re-
plenished directly from the primary supply
source.

     Oxygen gas from the supply system is
pressurized to 30 psig (2.1 kgf/sq cm) with
a separate compressor (not shown in Figure
3) and fed down through the hollow RAD
shafts and then radially outward through
small ducts located inside the diffuser
plate to the ceramic medium.  As oxygen gas
emerges from the upper and lower diffusion
bands, the rotational shear created by cen-
trifugal force forms ultra small bubbles in
the 50-100 micron range which do not co-
alesce as they move outward and pass over
the outside tapered edge of the diffuser
plate.  The primary function of the tapered
edge is to prevent turbulence which could
induce bubble coalescence.  The resulting
micron bubble dispersion resembles a mist
from which oxygen is rapidly and efficiently
dissolved in the mixed liquor.  The oxygen
transfer rate obtained with bubbles of this
minute size is sufficiently high to report-
edly sustain an oxygen utilization effi-
ciency greater than 90 percent in conven-
tional depth uncovered aeration tanks (4).

     A dissolved oxygen  (DO) feedback sys-
tem is used to control the oxygen feed rate
to the RAD's.  The control system, consist-
                                                                         OVERFLOW WEIR
                                                    DIFFUSERS
                                                       A
                                                    AERATION TANK FLOOR
                 Figure  3.   Functions  flow  diagram  of typical  MAROX system
                   employing rotating  active  diffusers.   (Reprinted,  with
                 modifications,  through  the courtesy of the FMC  Corporation.) (4)
                                             510

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ing of one or more DO probes, analyzers,
control valves, and electronic controllers,
automatically maintains the mixed liquor
DO concentration at a predetermined set-
point, within the tolerance range of the
equipment.  A one-module control system,
i.e., one probe, analyzer, control valve,
and controller each, is shown controlling
the oxygen feed rate to both diffusers in
Figure 3.  In a longer tank requiring 10-20
RAD's, multiple control modules would be
necessary with each module controlling the
feed rate to a bank of 3-5 diffusers.
     The  lack of necessity for a tank cover
 enables FMC to avoid the sealing problems
 with its  MAROX systems that must be con-
 sidered with the covered reactor systems.
 MAROX systems do not utilize internal
 staging baffles.  Although most covered re-
 actor systems designed to date have included
 staging baffles, they are not essential.
 Both the  open and covered reactor alterna-
 tives can be designed  compatibly with any
 of the commonly used activated sludge flow
 regimes.  Covered reactor systems are,
 however,  more naturally adapted to the con-
 ventional plug flow regime.  Where conven-
 tional activated sludge treatment is the
 flow regime of choice, the staged con-
 figuration more nearly approximates ideal
 plug flow and, other factors being equal,
 would be  expected to deliver an effluent
 with a slightly lower soluble BOD than an
 unstaged  system.

     Other features distinguishing the
 open and  covered reactor approaches from
 each other are:

          1.  The type of oxygen feed con-
 trol systems.  As mentioned previously.
 MAROX utilizes a DO based oxygen feed con-
 trol system.  The covered reactor systems
 control oxygen feed rate by maintaining
 a predetermined gas pressure in the first-
 stage head space.

          2.  Freeboard requirements.   Cov-
 ered reactors require more freeboard than
 open reactors.  The greater freeboard is
needed to provide adequate gas space for
 the umbrella throw pattern of the surface
 aerators normally employed in covered re-
actor designs.  Utilization of submerged
oxygen dissolution equipment obviates the
necessity for as large a freeboard with
the MAROX approach.
          3.  Carbon dioxide buildup.  It
is anticipated that MAROX systems will be
less subject to carbon dioxide buildup and
attendant pH depression than UNOX and OASES
systems due to the absence of a tank cover.
The degree to which cell respiration by-
products are vented from the open MAROX
reactor will depend primarily on surface
turbulence levels and the thickness of foam
buildup, if any, on the aerator surface.

          4.  Hydrocarbon buildup.  The
absence of a tank cover virtually elimin-
ates the possibility of accumulating an
explosive concentration of volatile hydro-
carbons over the aerator liquid surface.
It is assumed, therefore, that safety pre-
cautionary measures could be less extensive
with MAROX systems than with covered reactor
systems.

          5.  Oxygen feed pressure to the
oxygen dissolution systems.  The nominal
pressure of oxygen gas leaving cryogenic
and PSA generators is 3-5 psig (0.21-0.35
kgf/sq cm).  This is more than sufficient
to satisfy line and entrance losses to a
UNOX or OASES reactor and maintain a pres-
sure of 1-3 inches (2.5-7.5 cm) of water
in the first-stage vapor space.  Con-
versely, head loss through either of the
MAROX diffusers is substantial, requiring
an additional compressor to pressurize
generator output to 30 psig (2.1 kgf/sq cm).

     In comparing FMC's two open reactor
options, the several inherent advantages
of the RAD system over the FAD system are
expected to produce a pronounced preference
for the RAD alternative.  These advantages
include:

          - no requirement for prescreening
of aerator influent,

            no requirement for pumping mixed
liquor through the diffusers to create the
necessary shear to produce micron size bub-
bles,

            reduced oxygen dissolution
power requirements,

          - simplified installation, and

            less maintenance.
                                             511

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      METRO DENVER DEMONSTRATION PROJECT

     In June 1975, the U.S. Environmental
Protection Agency (EPA) awarded a $200,000
demonstration grant to Metropolitan Denver
(Colorado) Sewage Disposal District No. 1
to evaluate the MAROX system.  The remain-
der of the estimated total project cost
of $605,000 is being shared by the District
and FMC.  The EPA Grant No. is S803910.

     The evaluation is being conducted in
a segment of Metro Denver's existing air-
activated sludge plant.  The plant's sec-
ondary system consists of thirty-six 210-ft
(64-m) long, 670,000-gal (2536-cu m) aera-
tion bays and twelve 130-ft (39.6-m) dia-
meter clarifiers.  Each of the clarifiers
is mated with three aeration bays operated
in series to form 12 parallel secondary
trains.  Several of the bays have on occa-
sion been utilized for aerobic stabilization
of waste activated sludge.  Sludge is re-
cycled separately for each quadrant of the
plant, i.e., settled sludge from the three
clarifiers in any given quadrant is trans-
ferred to a common collection well from
where it is returned for distribution among
the three aeration trains in that quadrant.

     Approximately two-thirds of the aver-
age influent flow of 140 mgd (6.1 cu m/sec)
receives primary sedimentation before it
reaches the plant; the other third is pri-
mary settled on site.  A new 72-mgd (3.2
cu m/sec) UNOX facility, scheduled to
become operational in the fall of 1976,
will divert a significant fraction of the
primary effluent flow from the existing
overloaded air-activated sludge plant.

     Prior to grant award, it was mutually
decided that the large-scale MAROX system
to be evaluated by the District would
employ RAD's rather than the older FAD's
used in previous pilot-scale studies at
Metro Denver and on a previous EPA sup-
ported grant project at the Englewood,
Colorado, wastewater treatment plant (2)(3).
Thirteen RAD's were installed in the first
bay of aeration train No. 11 of the existing
Metro air plant.  The other two bays of
this train have been taken out of service
for the duration of the project.  Required
hydraulic modifications included the in-
stallation of a pipe to transfer mixed
liquor from the end of the first bay to
clarifier No. 11 and separate return and
waste sludge lines and pumps.  The latter
step was taken to isolate MAROX sludge
from the recycle sludge of the two remain-
ing operating air trains (Nos. 7 and 9)
of the plant's northeast quadrant.  A
liquid.oxygen storage tank and vaporizer
were installed adjacent to the converted
oxygen test bay.  During the first portion
of the evaluation, trucked-in liquid oxy-
gen is being used for oxygen supply.
However, the two 40-ton/day (36.3-metric
ton/day) cryogenic oxygen gas generators
that will serve the new Metro Denver UNOX
treatment plant will have excess capacity
initially.  For economic reasons, consid-
eration is being given to utilizing the
excess capacity for supplying oxygen to
the MAROX demonstration project once shake-
down of the cryogenic units is complete.
If this action is taken, a compressor will
have to be installed to raise generator
output pressure to a level compatible with
RAD operation.  A process schematic of the
Metro Denver MAROX test system is given
in Figure 4.  Dimensioned plan and section
views are shown in Figure 5.

     As indicated in Figure 5, the RAD's
are located on 21-ft (6.4-m) centers.  Six
of the 13 diffusers were installed in sets
of two in the first quarter of the tank
where oxygen demand is greatest.  The
remaining seven diffusers are located in
tandem on the longitudinal center line of
the aeration tank.  The first 11 RAD's are
driven by 10-hp (7.5-kw) motors and rotate
after gear reduction at 85 rpm.  The motors
for the last two RAD's are 7 1/2 hp-(5.6-
kw) units.  The rotational speeds of the
twelfth and thirteenth RAD's are 80 and
76 rpm, respectively.  The oxygen dis-
solution capability of the diffusers is
rated at 1500 Ib/day (680 kg/day) each in
the District's wastewater for a total
system capacity of 9.75 tons/day  (8.85
metric tons/day).  Previous proprietary
tests indicated these diffusers can be
operated up to 33 percent over their
rated capacity without significantly af-
fecting oxygen transfer efficiency.  On
this basis, assuming an average BODs re-
moval of 140 mg/1 and an oxygen require-
ment of 1.3 Ib 02/lb BODs removed  (1.3
kg/kg), the maximum sustained flow which
can be handled by this oxygen dissolution
equipment is roughly 17 mgd  (0.74 cu m/sec).

     Three DO probes and control systems are
employed to control oxygen feed to the Metro
Denver test bay.  One system controls the
feed rate to the first six diffusers, the
second to the middle four diffusers, and the
                                            512

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                                                                                                INFLUENT
                                                                                                WASTEWATER
             Figure  4.   Process  schematic of Metro  Denver MAROX  test system.
                  (Reprinted  through  the  courtesy of the  FMC  Corporation.)  (5)
                                                 >- -<
                                               ^LIQUID OXYGEN SUPPLY
                                               -CONTROL VALVE
                                                IFf^
                J-'1'!"
                                                            OXYGEN SUPPLY TO INDIVIDUAL DIFFUSERS
                                                DISSOLVED OXYGEN PROBE
                                                TOTAL THREE FURNISHED
                                                MOUNTED ON THE BASIN HAND RAIL
                                 r*A
)	(
)-  -i
^
                                                       ROTATING DIFFUSERS-
 Tl
}~ 15-0"
                              T  ^
                                                               3UAL SPACES AT2l'-0"= IB9'-0^
                                                                TOTAL 13 DIFFUSERS
                                                                  - 2IO'-O" LENGTH-
                                                                                       >-».A
                                                                                                 INFLUENT
                                                                                                 FROM PRIMARY
                                                                                                 SETTLING
                                                                                                 TANK
                                                     RETURN SLUDGE FROM SECONDARY CLARIFjER
                                                                          LIST OF EQUIPMENT FURNISHED BY FMC

                                                                          • BRIDGES, BRIOGt SUPPORTS, HAND RAILS

                                                                          • DIFFUSERS WITH DRIVE UNITS

                                                                          • LIQUID OXYGEN STORAGE TANK
                                                                          • VAPORIZER
                                                                          • OXYGEN SUPPLY
                                                                          • CONTROL PANEL (NOT SHOWN)

                                                                          • CONTROL INSTRUMENTATION [NOT SHOWN)
            SECTION A-A
Figure  5.   Dimensioned  plan and section views  of Metro Denver  MAROX test  system.
               (Reprinted  through  the  courtesy of the FMC Corporation.)  (5)
                                               513

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third to the last three diffusers.  Based
on mutual agreement, an initial DO setpoint
of 3.0 mg/1 was selected.  During the first
month following startup, the oxygen control
equipment exhibited a variance range of
±0.7 mg/1 from the desired setpoint.

     The RAD's and RAD drives are supported
from metal bridges which span the aeration
test bay, as illustrated in Figure 5.  The
bridges in turn are supported by stanchions
(not shown in Figure 5) running to the tank
floor.  The bridges were tied with minimal
defacing into the side walls of the test
bay to  prevent lateral movement.  Following
delivery of the key components of the
oxygen supply and dissolution systems to
the project site, the entire installation
including piping modifications was com-
pleted in six weeks.  Due in part to the
short period in which its system components
can be installed and the minimum structural
modifications required, the upgrading of
existing air-activated sludge plants as
exemplified by the Metro Denver demonstra-
tion project is expected to become an im-
portant MAROX application.

     From the section view of Figure 5, it
can be seen that surface impellers were not
provided with the RAD's.  The District has
experienced a float buildup of relatively
high solids concentration (2-3 percent TSS)
on the mixed liquor surface.  Under other
circumstances and with the proper removal
equipment, this float would constitute a
potentially attractive source from which
to waste excess sludge at a substantially
higher solids concentration than available
in secondary clarifier underflow.  Since
the District is not equipped to waste
sludge in this manner, the presence of
the float represents an operational and
esthetic liability.  To overcome this
problem, installation of an aeration test
bay overflow weir,  similar to the one
shown  in Figure 3,  is under consideration.
The weir would replace the present sub-
merged orifice through which the mixed
liquor now exits the aeration bay.  Utili-
zation of an overflow weir would promote
continuous transfer of floated solids to
the secondary clarifier before they could
accumulate on the  liquid surface.  Another
float  avoidance technique being evaluated
is the use of one or more down draft pro-
peller pumps to recirculate floated solids
back into the mixed liquor.  For long term
operation, the overflow weir option is be-
lieved to be a more positive and cost-
 effective method than either surface
 impellers on the RAD shifts or down draft
 propeller pumps.   For expediency on this
 finite length demonstration project, how-
 ever,  the down draft propeller pump
 technique may be selected,  even though
 it would add 6-12 percent to oxygen dis-
 solution system power requirements.   A
 decision will be made in time for imple-
 mentation during the month  of September
 1976.

     The major objective of the project
 from the District's  standpoint is to
 determine the technical  feasibility and
 attendant costs of converting its existing
 air-activated sludge plant  to a higher
 capacity (i.e.,  two  to three times  higher)
 open reactor,  oxygen-activated sludge  sys-
 tem.   If successful,  the District could
 potentially  avert another major secondary
 plant  expansion for  the  foreseeable  future,
 with the exception of the additional clar-
 ifiers which  would be needed to handle
 increases in  influent flow.   EPA's primary
 project  objectives are:   (1)  to demonstrate
 at  a representative  field scale an  altern-
 ative  oxygenation concept which has  been
 extensively and successfully evaluated at
 pilot  scale and  (2)  to define  reliable
 design criteria,  operating  conditions  and
 costs, and performance expectation for a
 system embodying  that concept  for use  by
 the  engineering community.

     Equipment  installation  and piping mod-
 ifications were completed in early May 1976.
The remainder of the month was devoted to
facility  shakedown and adjustments.  June
was utilized as a process start-up period
for training operators and refining a data
logging and retrival  system.  The evalu-
ation program was initiated  on July  1,  1976,
and will  continue for 10  months til]
April 30, 1977.  The  five planned phases
and corresponding dates of the  evaluation
program  are described below:

Phase I,  July 1976,
     Constant flow @  2 mgd  (0.39  cu m/sec);
     warm wastewater  temperatures; one
     clarifier  only  in use
 Phase  II, August-September  1976,
     Diurnally varied flow  @  7  to  14 mgd
     (0.31 to 0.61 cu m/sec);  warm waste-
     water temperatures;   second clarifier
     available, if necessary
 Phase  III, October 1976,
     Constant flow @  2 mgd  (0.34  cu  m/sec);
     cool wastewater  temperatures;  one
     clarifier  only  in use
                                             514

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 Phase  IV,  November-December  1976,
     Diurnally  varied  flow @  7  to  14 mgd
      (0.31  to 0.61  cu  m/sec); cool waste-
     water temperatures;  second clarifier
     available,  if  necessary
 Phase  V, January-April  1977,
     Constant flow  increased  in increments
     to  failure;  cool  wastewater tempera-
     tures;  two clarifiers in use

      Anticipated operating conditions  are
 not documented  here for each  planned phase
 because  of the  variability that will be
 introduced by diurnal  flow.   However,  for
 reference  purposes, baseline  operating con-
 ditions  are summarized below  for the 9-mgd
 (0.4 cu  m/sec)  constant flow  phases, as-
 suming an  average primary effluent BODs
 concentration of 140 mg/1, a  sludge return
 rate equal to 40 percent of  the influent
 flow rate, and  average mixed  liquor sus-
 pended solids  (MLSS) and mixed  liquor
 volatile suspended  solids (MLVSS)  concen-
 trations of 4000 and 3200 mg/1, respec-
 tively:

  Nominal Aeration Time (based on Q)
       =  1.79 hr
  Actual  Aeration Time  (based  on Q  + R)
       =  1.28 hr
  Food  to Microorganism (F/M)  Loading
       =  0.59 Ib BOD5 applied/day/Ib MLVSS
       under aeration (0.59 kg/day/kg)
  Volumetric Organic Loading
       =  117 Ib  BOD5 applied/day/1000 cu ft
       aerator volume (1503 kg/day/cu m)
  Secondary Clarifier Overflow Rate
       (based on total  surface area)
       =  678 gpd/sq  ft  (27.6 cu  m/day/sq m)
  Secondary Clarifier Overflow Rate
       (based on useful surface  area; ex-
       cludes effluent  launder area)
       =  746 gpd/sq  ft  (30.4  cu  m/day/sq m)
  Secondary Clarifier Mass Loading
       (based on floor  area)
       =  31.7 Ib MLSS/day/sq  ft
       (155 kg/day/sq m)

      Average operating and performance data
 for the  startup month  of June 1976 are pre-
 sented in  Tabl^7.   The average secondary
 effluent suspendecKsolids (TSS) concen-
 tration  of 30 mg/1  is^only marginally
 acceptable. Daily  log sheets reveal,  how-
 ever,  that this effluent parameter exhibited
 a steadily decreasing  concentration trend
 throughout the  30-day  period as operators
'became more familiar with system operation
 and sludge inventory management.  Effluent
TSS for the first 12 days of July averaged
20 mg/1, a 33 percent decrease from June.
The seven-day/week data collection program
depicted in Table 7 will be used, along with
several additional tests not conducted in
the startup month, throughout the planned
evaluation studies.  One of these additional
tests will be the periodic determination of
oxygen utilization efficiency.  This will
be accomplished with the aid of a 6-ft x 6-
ft (1.8-m x 1.8-m) floating dome.  Off gases
from a 36-sq ft (3.34-sq m) area of tank
surface will be collected inside the dome
and funneled through a gas flow and com-
position monitoring station.  The tent will
be moved to different sections of the
aeration test bay to arrive at a composite
or average utilization efficiency.

     Caution should be exercised in extrap-
olating the sludge production and oxygen
supply rates given in Table 7.  These values
are for one month of operation only and were
generated immediately following a period of
operator familiarization with a new process.
A better perspective of the relationship of
these important parameters to organic load-
ing will be gained from an evaluation of all
the data at the end of the project.

               CASE HISTORIES

     Operating and performance data and case
history summaries are presented below for 11
oxygen-activated sludge plants.  Ten of the
plants utilize UNOX oxygenation systems, the
other an OASES system.  All 11 plants are
documented in the listing of operating fa-
cilities provided in Appendix A.

     The case histories were selected to
illustrate a variety of process applications,
system component configurations, and plant
sizes.  Eight of the selected plants treat
municipal wastewaters; three are strictly
industrial applications.  Several of the
municipal installations receive a signifi-
cant fraction of their incoming loads from
industrial sources.  The reactor designs
for these plants represent a variety of
configurations including both rectangular-
stage systems and systems incorporating cir-
cular and arcuate stages within larger self-
contained circular tanks.

     In addition to operating and perform-
ance data, a flow diagram is presented for
each case history along with pertinent
background information, where known, lead-
ing to the selection of an oxygen system.
                                             515

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                    TABLE 7.  JUNE 1976 AVERAGE OPERATING AND PERFORMANCE
                    DATA FOR METRO DENVER OPEN REACTOR OXYGENATION PROJECT
Influent Flow	..9.5 mgd  (0.42 cu m/sec)
Return Sludge Flow.,	-3.8 mgd  (0.17 cu m/sec)
Return Sludge Flow/Influent Flow	40%
Pri.  Eff.  BODs	126 mg/1
Sec.  Eff.  BOD5	19 mg/1
BODs Removed Across Secondary	85%
Pri.  Eff.  TOG	87 mg/1
Sec.  Eff.  TOC	29 mg/1
TOG Removed Across Secondary	67%
Pri.  Eff.  TSS	88 mg/1
Sec.  Eff.  TSS	30 mg/1
TSS Removed Across Secondary	66%
MLSS	3050 mg/1
MLVSS	2610 mg/1  (volatile fraction = 85 . 6%)
Mixed Liquor DO	2.7 mg/1
Mixed Liquor Temperature	20°C
Return Sludge TSS	10,970 mg/1
Return Sludge VSS	9120 mg/1  (volatile fraction - 83.1%)
Depth to Clarifier Sludge Blanket	7.5 ft (2.3 m)
Nominal Aeration Time  (based on Q)	1.69 hr
Actual Aeration Time  (based on Q  +  R)	1.21 hr
F/M Loading	....0.68 Ib BODs applied/day/lb MLVSS under
                                                  aeration (0.68 kg/day kg)
Volumetric Organic Loading	.....Ill Ib BODs applied/day/1000 cu ft aerator
                                                  volume  (1432 kg/day/cu m)
Secondary Clarifier Overflow Rate
     (based on total  surface area)	716 gpd/sq ft (29.2 cu m/day/sq m)
Secondary Clarifier Overflow Rate
     (based on useful  surface area;
     excludes effluent launder area)	787 gpd/sq ft (32 cu m/day/sq m)
Secondary Clarifier Mass Loading
     (based on floor  area)	25.5 Ib MLSS/day/sq ft (124 kg/day/sq m)
Waste Activated Sludge Mass	5060 Ib/day (2295 kg/day)
Sludge Production Rate (based on
     waste sludge TSS  only)	0.60 Ib TSS/lb BODs removed (0.60 kg/kg)
Sludge Production Rate (based on
     waste sludge § sec.  eff. TSS)	0.88 Ib TSS/lb BODs removed (0.88 kg/kg)
Sludge Retention Time  (SRT)..	..2.3 Ib MLSS under aeration/(Ib waste  sludge
                                                  TSS + sec. eff.  TSS lost)/day  =2.3 days
RAD Power Draw	 . 109 hp (81 kw)
Oxygen Supplied	11,363 Ib 02/day (5154 kg/day)
Oxygen Supply Rate  (based on load) 	 1.14 Ib 02/lb BOD5 applied  (1.14  kg/kg)
Oxygen Supply Rate  (based on removal) 	 1.34 Ib 02/lb 6005 removed  (1.34  kg/kg)
Noteworthy  start-up, operating, and main-
tenance difficulties encountered are dis-
cussed.  Secondary system components and
any flow routing peculiarities are described
briefly.  Data available to the writer for
summarization herein varied from one month's
results at several plants to more than two
years' results at another location.

Decatur, Illinois (UNOX)

     Prior to the recent addition of a UNOX
system, the Sanitary District of Decatur's
wastewater treatment plant consisted of two
rectangular primary clarifiers, six Imhoff
tanks, 12 air aeration bays, three secon-
dary clarifiers, two trickling filters, one
primary anaerobic digester, one secondary
digester, one supernatant holding tank, and
tertiary and sludge lagoons.  Six of the
existing air aeration bays are of 1935
vintage; the other six are larger and were
installed in 1965.

     In July 1975, the liquid portion of a
comprehensive plant upgrading program was
                                            516

-------
 completed.  The heart  of  this upgrading
 effort was the conversion of three  of  the
 1965 air aeration bays to oxygen  service.
 The walls of these bays were extended  up-
 wards 4 ft (1.2 m) and the bays covered
 to provide the needed vapor space to sat-
 isfactorily control oxygen feed and inter-
 stage gas transport.  The remaining nine
 air aeration bays have been combined into
 an integrated system to operate in parallel
 with the oxygen unit in either the conven-
 tional mode or as a modified contact sta-
 bilization process.  The  nine bays are
 shown schematically in the flow diagram of
 Figure 6 as two tanks, one representing
 the six older 1935 bays,  the other the
 three newer 1965 bays.

     Coinciding with the  modifications to
 implement oxygen-activated sludge treat-
 ment, three new primary clarifiers and four
 new secondary clarifiers  were constructed.
 Two of the three new primaries have 100-ft
 (30.5-m) diameters and are in use contin-
 uously.  The third new primary has a dia-
 meter of 130 ft (39.6 m)  and is only used
 during severe storms with the overflow
 discharged directly to the receiving river
 following chlorination.   The new  secondary
 clarifiers are mated with the UNOX system,
 the old secondaries with  the revamped  air
 aeration facilities.  The diameter and
 side water depth (SWD) of the new second-
 aries are 100 ft (30.5 m) and 12.5 ft  (3.8
 m), respectively.  The old trickling fil-
 ters  (not shown in Figure 6) were abandoned
 in September 1975.  The old rectangular
 primary clarifiers (also  not shown in
 Figure 6) have been placed on standby  ser-
 vice.

     A program to upgrade the sludge han-
 dling portion of the plant is currently
 underway and is scheduled for completion in
 December 1976.  The old supernatant holding
 tank and old secondary digester are being
 converted to heated primary anaerobic  di-
 gesters to join the one existing primary
 digester.   When completed, supernatant will
 be returned directly to the plant headworks.
 Five of the existing six  Imhoff tanks
 (omitted from Figure 6) are being outfitted
 with covers to operate as non-heated sec-
 ondary digesters.   The sixth Imhoff tank
 will remain uncovered and serve as a holding
 tank for both oxygen and  air waste activated
 sludges  prior to separate thickening in a
new concentrator.   Waste  sludge is presently
returned to the primaries for thickening
before digestion.
      Each of the three oxygen trains is
divided into four stages.  The overall
dimensions of the oxygen reactor are  148
ft long x 77 ft wide x 14 ft SWD (45 m x
23.5 m x 4.3 m) with a freeboard of 4 ft
(1.2 m).   The oxygen dissolution system con-
sists of surface aerators combined with
bottom propellers for additional mixing.
The PSA oxygen generation unit has a design
output capacity of 17 tons/day (15.4 metric
tons/day).  The storage capacity of the
backup liquid oxygen supply tank is 43 tons
(39 metric tons).

      On the average, 55 to 60 percent of
the incoming organic load is from indus-
trial sources, primarily corn and soybean
processing.  Some of the industrial con-
tributors have their own treatment facil-
ities which discharge effluent into the
Decatur sewer system.  The particular mix-
ture of domestic,  industrial, and partially
treated wastes received at the Decatur
plant is conducive to the formation of a
poor settling filamentous sludge.  Fila-
mentous conditions have been a historical
problem with and continue to seriously
plague the air aerated trains.  According
to plant personnel,  filamentous infestation
is much less prevalent in the oxygen sludge,
but is present in sufficient quantities
that a substantially less dense settled
sludge is produced than predicted.   Even so,
oxygen clarifier underflow concentrations
range from 70-100 percent higher than
comparable data for settled air sludge.

      The inability to thicken oxygen sludge
during clarification to the degree planned
has resulted in lower MLSS and higher F/M
operating conditions than designed for.
These conditions have apparently not
adversely affected effluent quality which
remained good throughout the first year of
operation, .as indicated in Table 8.  The
somewhat higher effluent suspended solids
value shown for February corresponded to
an average influent flow equal to 115 per-
cent of design.  The effluent data given
in Table 8 represented UNOX system efflu-
ent quality prior to mixing with air sys-
tem effluent or subsequent treatment in the
tertiary lagoons.

     Recent communication with the assist-
ant plant manager elicited the following
observations on his part:

          1.  The oxygen system has con-
sistently outperformed the air system by
                                           517

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                        TABLE 8.   OPERATING AND PERFORMANCE DATA
                          FOR DECATUR, ILLINOIS OXYGEN SYSTEM
Operation
Parameter
Influent Flow (mgd)*
Aeration Detention Time, Q (hr)
F/M Loading
(kg BOD5/day/kg MLVSS)
Secondary Clarifier Overflow
Rate (gpd/sq ft)t
MLSS (mg/1)
Return Sludge TSS (%)
Reactor Influent BOD 5 (mg/1)
TSS (mg/1)
Secondary Effluent BOD5 (mg/1)
TSS (mg/1)
Design
17.7
1.6

0.62

560
5500
1.9
188
138
20
25
Aug.
1975
14.4
1.97

1.10

456
2700
0.55
157
139
9
22
Feb.
1976
20.4
1.39

1.47

645
3300
0.93
129
138
15
36
July
1976
14.1
2.01

0.91

446
2600
0.87
98
99
10
20
*1 mgd = 0.044 cu m/sec
tl gpd/sq ft = 0.041 cu m/day/sq m
 a wide margin, despite treating approxi-
 mately twice as much flow in a substantial-
 ly  smaller reactor volume.

          2.  The oxygen system has exhib-
 ited  excellent day-to-day process reliabil-
 ity and is generally capable of recovering
 from  slug loading upsets within 24 hours.

          3.  Oxygen dissolution and supply
 systems require more operator attention than
 conventional air processes, primarily be-
 cause of the greater amount of instrument-
 ation involved.  Several equipment mal-
 functions to date have been beyond the
 ability of the plant operating staff to
 correct and have required attention on the
 part  of the vendor.

          4.  Several PSA compressor out-
 ages  were experienced during early oper-
 ations due to an improper inner cooling
 system.  The cooling system was eventually
 redesigned and rebuilt and is now per-
 forming satisfactorily.

      The upgrading modifications imple-
 mented at Decatur have resulted in an in-
 crease in plant capacity from 20 mgd (0.9
 cu  m/sec) to 25 mgd  (1.1 cu m/sec) and a
 substantial improvement in total plant
 performance.  Two-thirds of the upgraded
 25  mgd (1.1 cu m/sec) capacity is assigned
 to  the new oxygen system, one-third to the
 existing air system.
Detroit (#1), Michigan (UNOX)

     Initial planning for expansion to sec-
ondary treatment at Detroit called for the
installation of a 1200 mgd (52.6 cu m/sec)
air-activated sludge facility to be com-
pleted over a four-phase construction period
spanning approximately ten years.  Two 150-
mgd (6.6-cu m/sec) air train modules were
to be installed during each construction
phase, yielding an eventual total of eight
modules.

     Coinciding with' Detroit's planning
program, the use of oxygen in the activated
sludge process was being investigated in a
federally supported research project at
Batavia, New York (1) (2)(3).  Based pri-
marily on promising results emanating from
this project, Detroit became interested in
utilizing oxygen in its own treatment sit-
uation.  The City made a decision in 1969 to
modify its first construction phase to
include one 150-mgd (6.6-cu m/sec) air
module and one 300-mgd (13.1-cu m/sec) UNOX
module.  The reactor tanks for both systems
were designed with identical outside dimen-
sions, meaning that the aeration detention
time of the oxygen system was to be one-half
of that of the air system.  The high-rate
treatment potential of the oxygenation
process was of utmost importance to the
City because of a serious land shortage
problem.
                                           518

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                  PSA GENERATOR  1 7TPD
u
      LOX
      STOR
      AGE
           BAR SCREEN
  INFLUENT
                           PRIMARY  CLARIFIERS
            TO LANDFILL    x
                          I WASTE SLUDGE   ^
                                                              BYPASS PEAK FLOWS
                                    ^	T
                                                    AIR   REACTOR
    UNOX REACTOR
                                                                            SUPER-
                                                                           NATANT

                                                                          HOLDING
                                                                            TANK
                              RECYCLE

                              SLUDGE

                                                                 ANAEROBIC
                                                                  DIGESTERS (2)
AIR CLARIFIERS ITO  LANDFILL
                                                                    WASTE SLUDGE

       Figure 6.  Flow diagram of Decatur, Illinois wastewater treatment plant.
  (Printed, with modifications, through the courtesy of the Union Carbide Corporation.)
                                        519

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     The construction contract awarded by
the City included process guarantee require-
ments for the UNOX system in the areas of
effluent quality, power consumption, and
oxygen consumption.  The efficacy of the
UNOX and air systems was to be compared in
parallel test runs.  Depending on the re-
sults of the tests, the two systems were
designed such that the 150-mgd (6.6-cu m/
sec) air train could be readily converted
to a 300-mgd (13.1-cu m/sec) oxygen train
by the addition of a tank cover, submerged
turbine/sparger units for oxygen dissolu-
tion, and three more secondary clarifiers.
With this possibility in mind, the com-
pressors which continuously recirculate
gas through the submerged turbine/sparger
units were double sized to handle 600 mgd
(26.3 cu m/sec).  If the test results
indicated superior performance by the air
train, the City retained the option by
virtue of the identical reactor designs of
switching the higher capacity oxygen system
to a 150-mgd (6.6-cu m/sec) air system by
removing the tank cover and substituting
air draft tubes for the oxygen dissolution
equipment.

     For the test runs, six secondary
clarifiers were to be mated with the oxygen
reactor, three with the air reactor.  The
clarifiers are of unique design with a
diameter of 200 ft (61 m), a SWD of 16 ft
(4.9 m), an extremely high average surface
overflow rate of 1600 gpd/sq ft (65 cu m/
day/sq m), rapid sludge removal suction
pipes, and a peripheral-feed  rim-takeoff
flow configuration.  Although the oxygen
module has been in operation since August
1974, the writer is not aware of the
publication of any officially conducted
comparative test results on the two sys-
tems to date.  Normal start-up problems
and delays in getting nine clarifiers com-
pleted reportedly contributed to the delay
in parallel testing.   Whether official test
data are eventually published or not, it
would appear that Detroit is committed to
oxygen use.  Two new 300-mgd (13.1-cu m/
sec') oxygen modules are now under construc-
tion as part of the City's second-phase
construction program.  The second-phase
oxygen systems will utilize OASES equip-
ment.  If Detroit decides at a future date
to convert the air train installed under
first-phase construction to oxygen service,
the City will have realized its ultimate
goal of 1200 mgd (52.6 cu m/sec) of treat-
ment capacity with four reactor modules
instead of eight.  A flow diagram for the
first-phase air and oxygen modules is given
in Figure 7.

     The large 30-ft (9.1-m) reactor SWD
employed in first-phase construction neces-
sitated the use of the submerged turbine
oxygen dissolution alternative.  The over-
all dimensions of the UNOX reactor are
600 ft long x 140 ft wide x 33 ft deep
(183 m x 42.7 m x 10.1 m).   Oxygen gas is
supplied to the UNOX system by a 180-ton/
day (163-metric ton/day) cryogenic gener-
ator.   A 900-ton (816-metric ton) liquid
oxygen storage tank provides backup.

     Following start-up, it became
evident that sufficient detail had not been
given to the design of the submerged tur-
bine assemblies.  Propeller failures and
gear box problems resulted from inadequate
materials selection and fabrication.  Re-
design and partial equipment replacement
were necessary to correct the deficiencies.
Another problem encountered by the plant
staff was obtaining a tight seal at the
joints between the outside edges of the
reactor cover and the reactor walls.
Despite experiments with several different
sealants and sealing procedures, this situ-
ation was only marginally rectified at the
time of this writing.  Cryogenic generator
performance has been very satisfactory with
minimal  downtime.  During the first 550
days of operation,  less than 2.5 percent
scheduled and 0.4 percent unscheduled out-
ages were experienced.

     Average operating and performance data
for the UNOX system are documented  in Table
9  for September 1975 and a  1-1/2 month per-
iod in the  spring of 1976.  These data were
generated at constant influent flow.  Impo-
sition of diurnal flow variations on the
UNOX system will be postponed  until the
remainder of the secondary treatment trains
under construction  come on-line.  It is
obvious that reactor influent  BOD5  con-
centrations have been considerably  lower
than expected.  The weaker  strength primary
effluent is partially attributable  to the
recent initiation of iron addition  to the
primary clarifiers  for phosphorus   removal.

     Two major  operational problems have
surfaced with the secondary clarifiers.
One involves achieving proper  peripheral
influent distribution to avoid short cir-
cuiting of  mixed liquor  solids directly up
to the rim-takeoff  weirs.  The other is the
extreme difficulty  encountered in getting
settled sludge  to thicken to acceptable
concentrations  prior to  removal  from the
                                            520

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                        TABLE 9.  OPERATING AND PERFORMANCE DATA
                        FOR  DETROIT  (#1), MICHIGAN OXYGEN  SYSTEM
Operation
Parameter
Influent Flow (mgd)*
Aeration Detention Time, Q (hr)
F/M Loading
(kg BOD5/day/kg MLVSS)
Secondary Clarified Overflow
Rate (gpd/sq ft)t
MLSS (mg/1)
Return Sludge TSS (%)
Reactor Influent BOD5 (mg/1)
TSS (mg/1)
Secondary Effluent BOD5 (mg/1)
TSS (mg/1)
Design
300
1.42

0.47

1600
6250
--
140
150
25
30
1975
302
1.41

0.58

1611
2340
0.66
44
105
6
9
March 29 -
May 9, 1976
299
1.42

1.05

1595
2750
0.85
101
240
17
31
 *1 mgd = 0.044 cu m/sec
 tl gpd/sq ft = 0.041 cu m/day/sq m
clarifiers.  The impact of the thin settled
sludge situation is evident in Table 9 in
low MLSS levels and high F/M loadings.
The Detroit oxygen sludge does have good
thickening properties as exemplified by the
ability to separately thicken waste sludge
to 4 percent solids in 24 hours without
chemical conditioners.  In the writer's
opinion, secondary clarifier operational
difficulties will continue as long as the
clarifiers are subjected to the inordin-
ately high overflow rates currently in use.

Fairfax County, Virginia (OASES)

     The Westgate plant is one of four
municipal wastewater treatment plants
operated by Fairfax County, Virginia.  This
plant, constructed in 1954, was originally
designed to remove 50 percent of the BODs
loading from a design flow of 8 mgd (0.35
cu m/sec).

     Basic features of the original Westgate
facility in sequence consisted of bar screen-
ing, comminution, primary clarification,
once-through aeration,  secondary clarifi-
cation, and chlorination.   Sludge recycle
pumps were not provided.   The main treat-
ment basin was divided into two parallel
tanks.  Each tank housed primary clarifi-
cation, aeration and secondary clarification
sections separated only by baffles.  Scrap-
er chains passed along the entire floor
length through all the sections of the
tanks.  The apparent purpose of the scrapers
was to move biological solids and grit
settling out in the secondary clarification
zones back to the primary clarification
zones where they could be removed from the
system.  Although the original plant was
not intended to function as an activated
sludge system, it is highly likely that
some settled solids were resuspended in the
aeration zones during scraping transport,
thus maintaining a small active biomass
population in those zones.  The decision
to forego installation of the additional
clarifier appurtenances, sludge recycle
equipment, and piping which would have
permitted operation in a conventional acti-
vated sludge mode was necessitated by fund-
ing limitations at the time of initial
construction.

     From 1954 to 1965, plant influent
flows increased gradually from 8 mgd  (0.35
cu m/sec) to slightly less than 10 mgd
(0.44 cu m/sec).  BOD  and suspended  solids
removals during this period averaged  approxi-
mately 50 and 65 percent, respectively.  By
1970 with plant flows having further  in-
creased to approximately 11 mgd (0.48 cu
m/sec, BOD  removal had dropped to 45 per-
cent and suspended solids removal to  55
percent.  In 1970, faced with the choice of
either upgrading BOD  removal efficiency to
80 percent or having a building moratorium
placed on the area served by the plant, the
County submitted a report to the State of
Virginia recommending that interim upgrading
steps be applied at Westgate pending  com-
                                            521

-------
                                            CRYOGENIC GENERATOR 180 TPD
                                                                    LOX
                                                                    STORAGE
    PICKLE LIQUOR
    FROM INDUSTRY

                             •«
                             jf  SLUDGE  J
INCINERATION
             I'SLUDGE THICKENING'I       i
     Jl
 VACUUM
FILTRATION
                                WASTE
                              SLUDGE
 TO LANDFILL
                                  f AIR
                                  REACTOR
                                                        SECONDARY
                                                     '(3) CLARIFIERS   (6)
                                       R£CJ^CLE_SLUDGE
                                              .CHLORINATION-
                                      EFFLUENT
            Figure 7.  Flow diagram of Detroit, Michigan wastewater treatment
               plant   Phase #1 construction.   (Printed, with modifications,
                  through the courtesy of the  Union  Carbide Corporation.)
                                          522

-------
pletion of an expansion program at the
nearby Alexandria, Virginia plant.  At that
time, the Westgate facility would cease
operations in favor of flow diversion to
Alexandria.

     The first interim upgrading approach
tried was the addition of ferric chloride
to the influent wastewater at the plant
headworks followed by anionic polyelectro-
lyte addition to the aeration zones.  This
technique yielded an average BOD  removal
of 71 percent from July 1970 through
October 1971, somewhat short of 80 percent
removal target.  The sludge resulting from
chemical addition proved to be more diffi-
cult to dewater than that of the original
plant.

     Laboratory tests indicated that com-
bining powdered activated carbon dosing to
the influent wastewater with the above
iron and polyelectrolyte additions could
potentially improve BOD  removal to 75 per-
cent.  Full-scale trials with carbon dosing
were abandoned in July 1971 after a short-
term run due to erosion and feed control
problems.  Data generated during the run
were inconclusive.

     During the latter portion of 1970, the
County and its engineering consultant con-
cluded that 80 percent interim BOD  removal
could be achieved more cost effectively
with a biological treatment system than
with a combination of chemical addition
procedures.  A decision was then made
following technical deliberations to imple-
ment biological treatment with an oxygen-
activated sludge process rather than a
high-rate air-activated sludge process
because of reliability and cost consider-
ations.  A contract was awarded to Air
Products and Chemicals, Inc. in the spring
of 1971 after competitive bidding to con-
vert the existing Westgate plant to an OASES
system.  A contract period of 210 days was
allowed to complete the job.

     The upgrading plan developed by the
County's engineer consisted of four prin-
cipal steps:

          1.  Conversion of the aeration
and secondary clarification sections of the
existing tanks into a two-train oxygenation
reactor leaving the primary clarification
sections intact.

          2.  Installation of two new
secondary clarifiers, each 120 ft  (36.6 m)
in diameter with a SWD of 11 ft  (3.4 m) and
suction lift scraper arms for removing
sludge.

          3.  Installation of waste acti-
vated sludge thickening capability in the
form of two flotation thickeners, each
having a surface area of 250 sq ft (23.2
sq m).

          4.  Installation of two 7-mgd
 (0.31-cu m/sec  sludge recycle pumps  and
separate sludge wasting pumps.

     A longitudinal section view of the
existing Westgate treatment basin prior to
conversion to an oxygen system is given in
Figure 8.   Some of the modifications re-
quired to effect the conversion are noted.
These included removal of the air diffusers
and downcomer piping, removal of the baffles
between the old aeration and secondary
clarification sections, removal of all old
effluent weir sections within the secondary
clarification sections proper,  removal of
the old sludge scrapers from the aeration
and secondary clarification zones, replace-
ment of the baffles separating the primary
clarification and original aeration zones,
and relocation of some sludge scraper
sprockets to the primary clarification
sections.   The converted oxygen reactor
was divided into four stages in each train.
The stages comprised in order 22, 44, 23,
and 11  percent of the total reactor volume.
Only the first three stages were covered,
the last stage being left open to the at-
mosphere because of the low oxygen demand
which would exist at that point.   The gas-
tight tank covers and liquid staging baffles
were fabricated from carbon steel and
coated with an epoxy-phenolic resin.   The
overall dimensions of the converted oxygen
reactor are 138 ft long x 82 ft wide x 12
ft SWD (42 m x 25 m x 3.7 m).

     A total of 36 surface aerators with
bottom impellers were installed for oxygen
dissolution and  mixing.  Eight of the
aerators (utilized at the front end of the
reactor) are 10-hp (7.5-kw) units; the
other 28 have 5-hp (3.7-kw) drives, yielding
a total installed nameplate power load of
220 hp (164 kw).  Liquid oxygen is stored
on-site and vaporized preceding introduc-
tion to the oxygenation system.

     Plant modifications were completed
and the converted system started up in
                                           523

-------
          PRIMARY
        CLARIFICATION
                                                                  OLD EFFLUENT OVERFLOW WEIR
/BAFFLE REMOVED
                                                        SPROCKETS RELOCATED
               Figure 8-  Longitudinal sectional view of pre-modified
                concrete tank at Fairfax County (Westgate) ,  Virginia
                 wastewater treatment plant.   (Reprinted from draft
                      report for EPA Contract No.  68-03-0405 .) (6)
November 1971, making Westgate the oldest
full-scale oxygen-activated sludge facility
in the world.

     A flow diagram of the modified plant
is shown in Figure 9.  Operation of the new
flotation thickeners was terminated after
several months.  It was found that thicken-
ing of excess activated sludge beyond that
afforded by gravity decant tanks was not
needed prior to mixing with primary sludge
and vacuum filtration.  The comminutor was
also removed from service several months
into the upgraded operation.

     Start-up difficulties were minimal and
of the type normally associated with "de-
bugging" a new system.  A process optimi-
zatjon program was undertaken for the County
by Air Products and Chemicals from late
January 1972 to May 1972.  The primary
purpose of the program was to define the
operating conditions for this first-of-a-
kind system which would result in a con-
sistently high level of plant performance.
Operating and performance data are present-
ed in Table 10 for the one-year period of
August 1972 through July 1973.  As indi-
cated, excellent effluent quality was
achieved, far exceeding the 80 percent
BOD  removal design specification, at an
average influent flow equal to 76 percent
of design capacity.  Primary  influent
rather than reactor influent  concentrations
are included  in Table 10 because represen-
tative sampling of primary effluent is not
possible.  Little alteration  of influent
wastewater characteristics is believed to
be effected by the primaries due to their
short detention time  (20-25 minutes).
             The Westgate story is a superb example
        of utilizing existing tankage to the fullest
        in an upgrading project intended to simul-
        taneously improve plant performance and
        increase plant capacity.  It is not known
        in view of the excellent performance
        achieved to date whether the upgraded


         TABLE 10.  OPERATING AND PERFORMANCE DATA
        FOR FAIRFAX COUNTY, VIRGINIA OXYGEN SYSTEM

                                          Operation
                                          Aug.1972-
               Parameter          Design  July 1973
Influent Flow (mgd)*
Aeration Detention
Time, Q (hr)
F/M Loading
(kg BOD5/day/kg MLVSS)
Secondary Clarifier Over-
flow Rate (gpd/sq ft)t
MLSS (mg/1)
Return Sludge TSS (%)
Primary Influent (mg/l)+
14

1.74

--

620
--
	

10.6

2.3

0.54§

469
4480
1.87

                        BOD5        220        161
                        TSS         173        162
       Secondary Effluent  (mg/1)
BOD5
TSS
44
12
19
       *1 mgd = 0.044 cu m/sec
       tl gpd/sq ft = 0.041 cu m/day/sq m
       tNot possible to sample reactor influent  as
           only a baffle wall separates primary
           clarifier from reactor.
       § Based on primary influent BOD5 rather  than
           reactor influent BOD5; indicated  value
           is, therefore, about  10 percent high.
                                           524

-------
        ABANDONED
      ACTIVATED CARBON
        SLURRY TANK
                                                                                    RECYCLE
                                                                                     PUMP
                                                     "F" STREET PUMPING STATION
             Figure  9.  Flow diagram of Fairfax County  (Westgate), Virginia
               wastewater treatment plant.   (Reprinted  from draft report
                            for EPA Contract No. 68-03-0405.)(6)
 plant will  still be abandoned when  the
 Alexandria  expansion  is  completed or not.
 The  total cost  of  the Westgate upgrading
 was  $1,672,000, of which $861,000 was
 expended for  the oxygen  dissolution and
 supply  systems  and reactor  tank modifi-
 cations.

 Gulf States Paper  Corporation,
Tuscaloosa,  Alabama (UNOX)

     A custom-designed,  self-contained, cir-
 cular UNOX system  was installed at  the
 Gulf States Paper  Corporation complex in
 Tuscaloosa, Alabama,   to  treat 9 mgd (0.39
 cu m/sec) of unbleached  kraft mill waste-
 water.   This type  of wastewater is deficient
 in nitrogen and phosphorus.   To overcome
 these deficiencies at Gulf States, phos-
phoric acid and anhydrous ammonia are
added to the primary effluent.

     A custom-designed circular UNOX sys-
tem differs from one of Union Carbide's
modular package oxygen plants in that it
is not  a standard off-the-shelf unit.   The
Gulf States oxygen system is composed of
three above-ground steel tanks each with
a diameter of 109 ft   (33.2 m),  a total
 depth  of  20  ft-(6.1 m),  and  a  SWD  of  16  ft
 (4.9 m).  Each tank is divided into a four-
 stage  oxygenation reactor  and  an arcuate
 clarifier.   Three of the four  stages  are
 also arcuate; one is circular.  Air-lift
 suction pickups are used to  withdraw  set-
 tled sludge  from the clarifiers.   Oxygen
 dissolution  and solids mixing  are  accom-
 plished with surface aerators  and  bottom
 propellers.  A four-bed  30-ton/day (27.2-
 metric ton/day) PSA oxygen gas  generator
 and a  43-ton (39-metric  ton) liquid oxygen
 backup storage tank and  atmospheric vapor-
 izer comprise the oxygen supply system.

     As shown in the flow diagram  presented
 in Figure 10, alum can be dosed to a  sepa-
 rate polishing clarifier following secondary
 clarification for the purpose  of effecting
 additional color removal.  This color re-
moval system has not been used to  any great
 extent to date, however, because of prob-
 lems with the alum recovery  equipment.

     The oxygen system itself has been in
operation since October  1974.  Following
start-up and "debugging," maintenance re-
quirements have been of a routine nature.
Operator attention on the unit ranges from
7-10 hr/week.
                                           525

-------
     Operating and performance data for the
months  of April and May 1975 are summarized
in Table 11.  Although the  system is oper-
ating at design flow, reactor influent
strength has been averaging only about 60
percent of design expectations. It has,


                 PSA GENERATOR 3OTPD
                            therefore, not been necessary  to operate
                            at as high MLSS levels as projected to main-
                            tain reasonable F/M loadings.  The effluent
                            values shown represent product quality from
                            the secondary clarifiers.  Additional sus-
                            pended solids removal is reportedly achieved
                                           1
                                                  LOX STORAGE
                 T_:r_T
                               NUTRIENT
                               ADDITION
                                                     —     UNOX REACTORS (3)
           PRIMARY CLARIFIER
   INFLUENT
                    O  TO BLACK LIQUOR
                       OXIDATION
                    PRIMARY
                    SLUDGE
               i
                                  FILTRATE



                                         ALUM ADDITION


                                   COLOR REMOVAL
     EFFLUENT




INCINERATOR  I        -^       |
                                                             THICKENER    WASTE

                                                                        SLUDGE I
                                       FILTER PRESS
    ALUM RECOVERY
                                ASH
          Figure 10.   Flow diagram of the  Gulf States Paper Corporation wastewater
            treatment plant - Tuscaloosa,  Alabama.  (Printed, with modifications,
                  through the courtesy of  the Union Carbide Corporation.)
                                         526

-------
in passage through the polishing clarifier
(operated without alum addition).  No data
were available to the writer to document
the improvement obtained in the polishing
clarifier.
 Approximately  one-half of the  PSA generator
 output  is  used in  the  activated  sludge  sys-
 tem;  the other half  is utilized  for  black
 liquor  oxidation.  Because of  the dual  role
 served  by  the  oxygen supply facilities,  the
 PSA unit was designed  to  produce 95  percent
 purity  oxygen  gas  rather  than  the standard
 90 percent product purity normally associ-
 ated  with  PSA  operation.
  TABLE  11.  OPERATING AND PERFORMANCE DATA
     FOR GULF STATES PAPER OXYGEN SYSTEM

                                   Operation
                                   Apr.   May
        Parameter          Design    1975
Influent Flow (mgd)*
Aeration Detention
Time, Q (hr)
F/M Loading
(kg BOD5/day/kg MLVSS)
Secondary Clarifier Over-
flow Rate (gpd/sq ft)f
MLSS (mg/1)
Return Sludge TSS (%)
Reactor Influent (mg/1)
BOD5
TSS
Secondary Effluent (mg/1)
BOD5
TSS
9.0

3.33

0.36

630
4700
1.9

200
100

30
50
9.0

3.33

0.37

630
3000
1.2

125
60

12
50
*1 mgd = 0.044 cu m/sec
tl gpd/sq ft = 0.041  cu m/day/sq m
 Lederle Laboratories, Pearl River,
 New York  (UNOX)
      Lederle  Laboratories,  a division  of
 American Cyanamid,  manufactures  pharma-
 ceuticals,  the majority of  which are anti-
 biotics.  The waste stream  resulting from
 production operations has a very high  and
 variable organic carbon content.  The  plant
 wastewater flow which  remains relatively
 constant at about 1.0 mgd (0.044 cu m/sec)
 can have a BOD5 loading as  high  as 32,500
 Ib/day (14,740 kg/day).

      Prior to the spring of 1972, an air
aeration system was used to treat plant
wastes.  The daily operations of this sys-
tem were marked by persistent odor problems
and inconsistent performance, arising from
the highly variable organic load.  A UNOX
system was designed to replace the existing
air aeration facilities.  Start-up occurred
in March 1972, which makes it the oldest
permanent full-scale UNOX facility in
existence.

     A flow diagram of the new oxygenation
treatment plant is given in Figure 11.  The
two-train reactor has overall dimensions of
148 ft long x 74 ft wide x 14.5 ft deep
(45 m x 22.6 m x 4.4 m) with a SWD of 10 ft
(3.0 m).  The lead reactor stages are larger
than the second or third stages to accom-
modate the high oxygen demand of the in-
coming wastewater.  Polymers are added
ahead of the single primary clarifloccula-
tor to lower the suspended solids concen-
tration entering the secondary system as
much as possible.  The three circular sec-
ondary clarifiers each have a 40-ft (12.2-
m) diameter, a 10-ft (3.0-m) SWD, and a
plow-type sludge scraper.  A 15-ton/day
(13.6-metric ton/day) PSA generator and a
52-ton (47-metric ton) liquid oxygen back-
up tank provide oxygen supply.

     Start-up difficulties included a
foaming tendency which ceased once a good
biomass had been established, and mixed
liquor solids deposition caused by recycle
of large amounts of lime and alum precipi-
tates  in the filtrate from the vacuum
filter which are not effectively captured
in the primary clariflocculator.  Solids
deposition was alleviated by adding bottom
mixers to the initially supplied surface
aerators.  The PSA oxygen generator experi-
enced  upwards of  10 percent outage follow-
ing start-up due  to valve actuator problems.
This unit was one of the first on-line
molecular sieve applications geared to
producing  oxygen gas for wastewater treat-
ment.  As such, some experimentation was
necessary to determine proper lubricating
procedures for the valve actuators and to
procure sufficiently rugged valve equipment
to withstand rapid cycling.  Following
final  modifications in mid-1973, total un-
scheduled PSA generator downtime has been
reduced to less than one percent.

     Odor complaints from neighboring
residents numbered more than 80  in  1971.
Complaints have not been received since
the oxygen system went  into  operation.
                                            527

-------
                 PSA GENERATOR 15 TPD
             GRIT
           CHAMBER
     PRIMARY
CLARIFLOCCULATOR
INFLUENT
                                                      J
                                                             LOX
                                                             STORAGE
                                                     UNOX REACTOR
                          PRIMARY
                          SLUDGE
                             RECYCLE SLUDGE

                                    SECONDARY CLARIFIERS
                —-CHLORINATION
             EFFLUENT1       '
            ^    FILTRATE
                                           EFFLUENT
                                           POLISHING
                                 I       -^- WASTE SLUDGE I          J
             TO LANDFILL
                    	_^                • I     i  ^_
                      ^-k. VACUUM      If     |r^
                    
-------
                          TABLE 12.  OPERATING AND PERFORMANCE DATA
                           FOR LEDERLE LABORATORIES OXYGEN SYSTEM
Operation

Parameter

Influent Flow (mgd)*
Aeration Detention Time, Q (hr)
F/M Loading
(kg BODs/day/kg MLVSS)
Secondary Clarifier Overflow
Rate (gpd/sq £t)t
MLSS (mg/1)
Return Sludge TSS (%)
Reactor Influent BOD5 (mg/1)
TSS (mg/1)
Polishing Clarifier Effluent BOD5 (mg/1)
TSS (mg/1)

Design

1.5
13

0.42

540
8000
2.8
1600
--
160
--
2 Trains
Oct. 1972

1.0
19.5

0.17

360
11,500
3.5
1400
800
80
70
1 Train
Nov. 1972
(3 weeks)
1.0
9.75

0.45

360
9600
3.0
1500
1300
90
60
*1 mgd = 0.044 cu m/sec
tl gpd/sq ft = 0.041 cu m/day/sq m
 clarifiers  have  been   corrected.   Settled
 sludge  no  longer fills up  the  secondaries
 and spills  over  into  the polishing clari-
 fier.   With the  polishing  clarifier serving
 in its  intended  role,  effluent 6005 and
 suspended  solids concentrations now gener-
 ally average around 50 and 10  mg/1,  respec-
 tively.

 Littleton,  Colorado (UNOX)

     The City of  Littleton, Colorado, se-
 lected a modular  UNOX  system for a recent
 plant expansion.  The  modular  unit used for
 Littleton is an  off-the-shelf  package sys-
 tem  contained within one circular  above-
 ground steel tank.  The tank,  82 ft  (25 m)
 in diameter x 15  ft (4.6 m) deep [SWD = 12
 ft  (3.7 m)], is divided by internal walls
 into a two-stage  oxygen reactor, an arcuate
 secondary clarifier; a single-stage air
 aerobic sludge digester,  and a  chlorine
 contact chamber.  The  arcuate  clarifier is
 equipped with floating bridge mounted air
 lift suction equipment for withdrawing
 settled sludge.

     The new oxygen train operates  in par-
 allel with  two existing trickling filters.
 Feed to the trickling  filters  is first set-
 tled in the plant's existing primary clari-
 fier.  The  oxygen reactor receives raw
degritted municipal wastewater  directly.
A flow diagram for the Littleton plant is
presented in Figure 12.

     The combined liquid volume of the two
oxygen reactor stages is 97,000 gal  (367
cu m).  Surface aerators connected by
shafts to bottom propellers are employed
for oxygen dissolution and mixing.  Due to
the small size of the treatment plant, an
on-site oxygen gas generating facility was
not provided.  Instead, liquid oxygen is
trucked in and stored in a 43-ton (39-
metric ton) tank, from where it is dir-
ected through an atmospheric vaporizer for
conversion to the gaseous form before
entering the oxygenation reactor.

     The UNOX package system became oper-
ational in February 1974.  A major oper-
ating difficulty was immediately encountered.
The original uncovered air aerobic sludge
digester was equipped with mechanical sur-
face aerators.  Aerator icing occurred in
the cold Colorado winter climate with re-
sulting poor volatile suspended solids
(VSS) reduction.  The problem was rectified
by installing a steel cover over the di-
gester area along with urethane foam insu-
lation and supplementing the surface aer-
ators with an air blower and diffusers to
provide adequate air circulation.  VSS re-
ductions have since ranged from 50-60 per-
cent .

     Influent flow to the oxygen portion of
the Littleton plant has varied from 0.9 mgd
                                            529

-------
       GRIT CHAMBER
                                         TRICKLING FILTERS(2)
INFLUENT
    SUPERN
                                                                     FINAL CLARIFIER
          k

          ATAIMT
                                                      _^__ WASTE SLUDGE
                    I    -*——
PRIMARY ANEROBIC DIGESTER — ——-'
                           SUPERNATANT
            I
                           I
          *
          SECONDARY DIGESTER
            I              »
                    I
                                                   J
                                                                       CHLORINATION
                                                   UNOX REACTOR
           SLUDGE DRYING BEDS
                                .— TO  LANDFILL
                                                                                  EFFLUENT
               Figure 12.  Flow diagram of Littleton, Colorado wastewater
                treatment plant.   (Printed, with modifications, through
                    the courtesy of the Union Carbide Corporation.)
(0.04 cu m/sec)  to  1.4  mgd  (0.06  cu m/sec)
since start-up.   The three-month average
data summarized  in Table 13 for the summer
1975 period indicate the  oxygen system is
performing within effluent design specifi-
cations.

Morganton, North Carolina  (UNOX)

     A UNOX facility designed to treat 8 mgd
(0.35 cu m/sec)  of municipal wastewater
combined with substantial industrial con-
tributions resulting from textiles produc-
tion and poultry processing went on-stream
at Morganton, North Carolina, in January
                                         1975.  As  indicated in the plant flow dia-
                                         gram  (Figure  13),  primary clarification was
                                         not included  in  the design.   The two-train
                                         oxygen reactor was constructed in an un-
                                         usual box  configuration with   four stages
                                         per train.  Each stage is 44 ft (13.4 m)
                                         square yielding  overall length and width
                                         dimensions  of 88 ft (26.8 m) and 176 ft
                                         (53.6 m),  respectively.  The total reactor
                                         depth is 14 ft  (4.3 m)  including a 4-ft.
                                         (1.2-m)  freeboard.

                                             Oxygen system equipment consists of
                                         surface  aerators with bottom impellers for
                                         oxygen dissolution and mixing and a 26-ton/
                                            530

-------
 TABLE 13.   OPERATING AND PERFORMANCE DATA
   FOR LITTLETON, COLORADO OXYGEN SYSTEM
        Parameter
       Operation
        June-Aug.
Design    1975
Influent Flow (mgd)*
Aeration Detention
Time, Q (hr)
F/M Loading
(kg BOD5/day/kg MLVSS)
Secondary Clarifier Over-
flow Rate (gpd/sq ft)t
MLSS (mg/1)
Return Sludge TSS (%)
Reactor Influent (mg/1)
BOD5
TSS
Secondary Effluent (mg/1)
BOD5
TSS
1.25

1.9

0.6

500
5600
2.8

200
240

20
25
1.1

2.16

0.6

440
4000
2.4

160
185

12
24
*1 mgd = 0.044 cu m/sec
tl gpd/sq ft = 0.041  cu m/day/sq m
 day  (23.6-metric ton/day) PSA generator
 and  28-ton  (25.4-metric ton) liquid oxygen
 backup tank for oxygen supply.  The PSA
 generator was outfitted initially with one
 one-half size compressor.  A second half-
 size compressor will be added at a later
 date when plant flows increase.  The two
 new  secondary clarifiers are 80-ft (24.4-m)
 diameter units with 10-ft  (3.0-m) SWD's and
 rapid sludge removal and grease skimming
 capabilities.

      Process and mechanical reliability have
 been excellent in the year and half since
 start-up. PSA generator availability has
 exceeded 99.5 percent.  A major operational
 problem in the form of high fat and grease
 loadings (often in excess of 100 mg/1) from
 the  local poultry processor, however, has
 prevented consistent attainment of effluent
 quality objectives.  No satisfactory method
 exists for rejecting these objectionable
 materials from the secondary system.  The
 fat  and grease which are only slowly bio-
 degradable pass to the final clarifiers
 and  collect on the liquid surfaces.  Al-
 though skimming devices were provided, much
 of the scum escapes the finals over the
 weirs taking with it significant quantities
 of enmeshed biofloc.  Consequently, effluent
 suspended solids have reached levels as
 high as 80-100 mg/1.  The problem is further
 accentuated by a hydraulic regime which
transports final clarifier skimmings to the
aerobic digesters and then recycles the
digester skimmings to the plant headworks
for recycle through the secondary system.

     Efforts to remove a large fraction of
the fat and grease load through pretreat-
ment at the poultry processing site have
been unsuccessful.  Consideration is now
being given to intercepting the skimmings
from the aerobic digesters and disposing of
them separately.  When this technique has
been evaluated for short periods on a trial
basis, effluent clarity and suspended solids
removals have improved measurably.  The
difficulties encountered at Morganton
appear to the writer to consitute a com-
pelling argument for the inclusion of pri-
mary clarification facilities in any future
designs faced with similar wastewater char-
acteristics.

     Two months of operating and perform-
ance data are summarized in Table 14.  Ef-
fluent quality documented for March 1975 is
typical of months when the influent grease
load has been somewhat lower than normal
and represents about the best performance
level that can be achieved under present
conditions.  In April 1975, the influent
grease load was up, and the monthly average
effluent suspended solids concentration in-
creased accordingly.  The much higher than
anticipated influent suspended solids con-
centrations for these two months indicate
that primary clarification would probably
have been a desirable and justifiable
feature aside from grease removal consider-
ations.
                     North Lauderdale,  Florida (UNOX)

                          An off-the-shelf modular UNOX system
                     was installed at North Lauderdale, Florida,
                     to serve a population base of approximately
                     10,000 people.   This package system consists
                     of a two-stage oxygen reactor,  an arcuate
                     secondary clarifier, and an uncovered single-
                     stage air aerobic  sludge digester.  The ar-
                     cuate clarifier has an air lift suction
                     device mounted from a floating  bridge for
                     removing settled sludge.  The air aerobic
                     digester is equipped only with  mechanical
                     surface aerators:   it was not necessary to
                     provide supplemental compressed air as at
                     Littleton.

                          The entire secondary complex is con-
                     tained within one  circular. 95-ft  (29-m) dia-
                                            531

-------
              PSA GENERATOR 26 TPD
                                                         LOX STORAGE
                                                                     BAR SCREEN
                UNOX REACTOR
                                     f
                               ii
                                                                                  INFLUENT
                                                                 RECYCLE SLUDGE
                     T
                                   1   AERATED GRIT  1
                                                     I
   EFFLUENT
                                                  SECONDARY
                                                  CLARIFIERS (2)
                                                                             11
     CHLORINATION
V
                    I df CENTRIFUGES (2)'
           POLYMER   , |        X-V     I
                   —i  ^— — — i  —•   \—t ^^ ^J •
                                                          CENTRATE
                                    TO LANDFILL
           Figure 13.   Flow diagram of Morganton,  North Carolina wastewater
              treatment plant.   (Printed,  with modifications,  through the
                      courtesy  of the Union Carbide Corporation.)
meter, 15-ft (4.6-m) deep, above-ground steel
tank.  The tank's SWD is 12 ft (3.7 m).  Un-
like the Littleton modular unit, a separate
external chlorine contact chamber was pro-
vided rather than including it in the pack-
age system.  Granular media filters are
available for effluent polishing, although
to date they have not been  used.  Raw
degritted municipal wastewater is fed di-
rectly to the oxygen system.  Excess acti-
vated sludge is dewatered either by cen-
trifugation or on sand drying beds.  A flow
diagram of the new North Lauderdale treat-
ment plant is shown in Figure 14.

     Oxygen dissolution and mixing are ac-
complished in the 129,000-gal (488-cu m)
                                     oxygen reactor with  surface  aerators  and
                                     supplemental bottom  agitators.   A 43-ton
                                     (39-metric ton)  liquid  oxygen  storage tank
                                     and attendant atmospheric  vaporizer com-
                                     prise the oxygen  supply system.

                                          The plant was placed  in operation in
                                     early July 1975.  To date, influent flow  has
                                     been averaging only  about  65 percent  of the
                                     design flow of 2  mgd (0.09 cu  m/sec), al-
                                     though wastewater strength has been some-
                                     what higher than  anticipated.   No signifi-
                                     cant operating problems have been encount-
                                     ered.  Performance as exhibited by the
                                     average data for  September 1975 shown in
                                     Table 15 has been excellent.
                                            532

-------
                         TABLE 14.  OPERATING AND PERFORMANCE DATA
                        FOR MORGANTON, NORTH CAROLINA OXYGEN SYSTEM
                                                              Operation
                  Parameter
     Design  March   APril
         K    1975    1975
Influent Flow (mgd)*
Aeration Detention Time, Q (hr)
F/M Loading
(kg BOD5/day/kg MLVSS
Secondary Clarifier Overflow
Rate (gpd/sq ft)f
MLSS (mg/1)
Return Sludge TSS (%)
Reactor Influent BOD (mg/1)
TSSb(mg/l)
Secondary Effluent BOD (mg/1)
TSSb(mg/l)
8.0
3.5

0.53

800
6000
3.0
350
400
27
25
4.7
6.0

0.31

470
5600
2.1
364
836
42
29
5.9
4.7

0.33

590
6400
1.6
357
946
32
79
  *1 mgd = 0.044 cu m/sec
  tl gpd/sq ft = 0.041 cu m/day/sq m
  TABLE  15.  OPERATING AND  PERFORMANCE  DATA
 FOR  NORTH  LAUDERDALE, FLORIDA OXYGEN SYSTEM

                                  Operation
Parameter
Influent Flow (mgd)*
Aeration Detention
Time, Q (hr)
F/M Loading
(kg BODs/day/kg MLVSS)
Seconday Clarifier Over-
flow Rate (gpd/sq ft)t
MLSS (mg/1)
Return Sludge TSS (%)
Reactor Influent (mg/1)
BOD5
TSS
Secondary Effluent (mg/1)
BOD 5
TSS
Design
2.0

1.56

0.68

525
5600
2

200
130

20
20
Sept. 1975
1.3

2.4

0.68

541
4500
1.5*

245
180

<10
<10
 1 mgd = 0.044 cu m/sec
tl gpd/sq ft = 0.041 cu m/day/sq m
      return sludge rate
Speedway, Indiana (UNOX)

     In June 1972, a new 7.5 mgd (0.33 cu m/
sec) UNOX installation was placed in oper-
ation at Speedway, Indiana.  This was the
first municipal UNOX facility to be com-
pleted.  Of all the oxygen-activated sludge
wastewater treatment systems now in oper-
ation, the Speedway plant was preceded only
by the municipal OASES plant at Fairfax
County, Virginia, and the industrial UNOX
plant at the Lederle Laboratories in Pearl
River, New York.

     The flow diagram in Figure 15 indicates
that the Speedway oxygen system is of con-
ventional design.  The two-train oxygen re-
actor is preceded by primary clarification.
Three of the six primaries are existing
units; the other three are converted sec-
ondary clarifiers from the City's old
trickling filter treatment facility.  Each
of the four reactor stages per train is
22 ft (6.7 m) square with a 16-ft (4.9-m)
SWD.  The overall dimensions of the two
reactor tanks taken together are 88 ft long
x 44 ft wide x 20 ft deep (26.8 m x 13.4 m
x 6.1 m).   Three new 65-ft (19.8-m) dia-
meter, 10-ft (3.0-m) SWD secondary clari-
fiers with the increasingly popular rapid
method of removing settled sludge were
provided.   At a future date as needed,
plant capacity can be increased to 10 mgd
(0.44 cu m/sec) by the construction of one
additional secondary clarifier.

     The UNOX reactors were designed to use
surface aerators attached by shafts to
bottom agitators for oxygen dissolution
and mixing.  A three-bed  5-ton/day (4.4-
metric ton/day) PSA unit generates oxygen
gas on-site.  A 7-ton (6.4-metric ton)
liquid oxygen storage tank and accompanying
atmospheric vaporizer were furnished for
reserve.  Profiting from difficulties ex-
perienced with earlier four-bed PSA gen-
                                           533

-------
                            BAR SCREEN
 INFLUENT
                 COMMINUTOR
                                                      UNOX REACTOR
       TO LANDFILL
                                 SUPERNATANT

                              SLUDGE
                                                      CHLORINE INJECTION
        CENTRIFUGES V- —r	——'

                          I      DRYING BEDS
                                            CHLORINE CONTACT CHAMBER

             Figure 14.  Flow diagram of North Lauderdale,  Florida wastewater
                treatment plant.   (Printed,  with modifications,  through the
                        courtesy of the Union Carbide Corporation.)
erator designs at Lederle Laboratories and
on a U.S. EPA co-sponsored demonstration
grant project at the Newtown Creek plant in
Brooklyn, New York (3),  particularly as
related to valves and lubricants,  the sec-
ond generation three-bed design employed
at Speedway has proven  to be highly reli-
able with less than 1-1/2 percent  total
downtime for scheduled  and unscheduled
maintenance.

     Waste activated sludge is recycled to
the primaries for co-thickening with raw
sludge.  The mixed sludges are then pumped
to a holding tank which  feeds a Zimpro wet
oxidation  system designed to condition
sludge for dewatering.   Conditioned sludge
is dewatered by vacuum  filtration  prior
to being trucked to landfill.  Periodic
and lengthy shutdowns of the wet oxidation
system placed considerable stress on the
main stream treatment components for much
of the early history of this new facility.
Unable to truck liquid sludges away, it
was frequently necessary to return mixed
raw and waste sludges from the sludge
holding tank to the primary clarifiers.
When the primaries filled up, sludge over-
flowed into the oxygen reactors along with
primary effluent.  The oxygenation tanks
during these periods in effect served
more as aerobic sludge digesters than
conventional activated sludge systems.

     Considering the difficulties imposed
by the above conditions on the management of
                                           534

-------
                     PSA GENERATOR 5 TPD
                                              LOX STORAGE
                GRIT  PRIMARY CLARIFIERS (6) '
             REMOVAL
                                                          UNOX REACTOR
         SCREEN
                    ji
                    1
                    | WASTE SLUDGE
MIXED
SLUDGE
A
                                                                 SECONDARY CLARIFIERS
               CHLORINATION
           -*-V
        EFFLUENT
                                   	L.
                                       HOLDING  TANKS (2)    ZIMPRO
                                                        RECYCLE SLUDGE

                                                                    SUPERNATANT
                                                                   L_ . . . v — — . .
                         — _              ~"t^_ FILTRA_[E         J._— ILK
                  Figure  15.  Flow diagram of Speedway, Indiana wastewater
                  treatment plant.   (Printed, with modifications, through
                      the  courtesy of the Union Carbide Corporation.)
                                                                                  VACUUM
                                                                                  FILTER
secondary sludge inventory,  oxygen system
performance was superb.   Annual average
effluent 6005 and suspended  solids con-
centrations were low in  both 1973 and 1974,
as indicated in Table 16.  The highest
monthly average BODs and suspended solids
levels recorded in these two years were
16 and 30 mg/1, respectively.   Also shown
in Table 16 are the results  of one month
of one-train operation in early 1976.
Occasional one-train operating tests have
been conducted by plant  personnel to
evaluate oxygen system performance at
loadings comparable to design values.
          Union Carbide Corporation,
          Sistersville, West Virginia (UNOX)

               The Chemicals and Plastics  Division
          of the Union Carbide Corporation placed a
          UNOX system in operation in November 1973
          to treat waste products from the manufacture
          of silicones.  The resulting wastewater
          stream has a high organic carbon content and
          also contains substantial quantities of
          acid and various oils.  Conditioning is
          necessary ahead of the biological process
          to neutralize the acid and remove the oil.
          A holding pond (not included in  the flow
                                           535

-------
                        TABLE 16.  OPERATING AND PERFORMANCE DATA
                           FOR SPEEDWAY, INDIANA OXYGEN SYSTEM
                                                       2 Trains*
                                                     1973     1974
                                                               Operation
     Parameter
                                          Design
                        1 Traint
                        Jan. 16  -
                      Feb. 18, 1976
Influent Flow (mgd)*
Aeration Detention Time, Q (hr)
F/M Loading
(kg BOD5/day/kg MLVSS)
Secondary Clarifier Overflow
Rate (gpd/sq ft)§
MLSS (mg/1)
Return Sludge TSS (mg/1)
Reactor Influent BODs (mg/1)
TSS (mg/1)
Secondary Effluent BOD5 (mg/1)
TSS (mg/1)
7.5
1.48

0.51

750
4200
2.2
110
96
15
20
4.4
2.52

0.20

440
6080
1.54
91
179
9
16
4.6
2.41

0.51

460
6600
1.3
73
109
9
14
4.3
1.29

0.70

645
4760
1.66«
114
118
13
18
*Three secondary clarifiers  in  operation
tTwo secondary clarifiers  in operation
*1 mgd = 0.044 cu m/sec
§1 gpd/sq ft = 0.041 cu m/day/sq m
^Excludes reported values  for Feb.  6, 1 -,  8,  and  9
 diagram  shown in Figure 16) is utilized
 for  diversion of large spills that cannot
 be adequately preconditioned.

     This  inhouse Carbide project marked the
 first utilization of circular reactor/clari-
 fier UNOX  combination tanks.  Two such
 units were installed, each consisting of
 three arcuate reactor stages and one cir-
 cular reactor stage and an arcuate final
 clarifier.   In contrast to the above-ground
 designs  employed in later circular UNOX
 facilities (refer to Gulf Stages Paper Cor-
 poration;  Littleton, Colorado; and North
 Lauderdale,  Florida), the Sistersville
 tanks were installed in conventional below-
 ground fashion.  The custom-designed dimen-
 sions of the Sistersville units are:
 diameter   102 ft (31.1 m), total depth -
 14 ft (4.3 m), and SWD - 10 ft (3.1 m).
 The  final  clarifiers are equipped with air-
 lift suction equipment for removing settled
 sludge.

     Surface aerators connected to bottom
 impellers  are used to achieve oxygen dis-
 solution and oxygen and biomass dispersion.
 Oxygen is  supplied in a rather unusual
 manner from an on-site industrial cryogenic
 nitrogen gas generator which produces 15
 tons/day (13.6 metric tons/day) of oxygen
 gas  as a by-product.  Prior to start-up of
the silicones wastewater treatment facility,
the by-product oxygen was wasted to the
atmosphere.

     Problems were initially encountered
with the floating bridge mechanism from
which the sludge scraping and pickup devices
are supported.  Corrective action required
redesign and relocation of the bridge cen-
ter support.  Later arcuate clarifier de-
signs profited from the Sistersville experi-
ences .

     Occasional toxic spills, primarily
from copper, have resulted in biological
upsets.  The oxygen-activated sludge sys-
tem has usually recovered from these spills
within one week.  Following an in-plant
survey, a program is underway to eliminate
copper from plant discharges in concentra-
tions which are toxic to microorganisms.

     Average monthly operating and perform-
ance data for August and December 1975 are
presented in Table 17.  At influent load-
ings equal to 85-95 percent of hydraulic
capacity, effluent quality has been signifi-
cantly better than required by the design
specifications.  The difficulty in settling
silicone fines can be noted in the effluent
suspended solids levels which are two to
three times the effluent BOD,- concentrations.
                                            536

-------
  CRYOGENIC GENERATOR 15 TPD
                                         LOX STORAGE
                                                                 UNOX REACTORS (2)
                                       NUTRIENT
 LIME ADDITION                         ADDITION

       t   PRIMARY API      EQUIL.ZATION
           SEPARATOR          BASIN
11
                                       EFFLUENT
                                  DEWATERING POND |
INFLUENT
                SUPERNATANT
                                           TO  LANDFILL
              Figure  16.  Flow diagram of Union Carbide Corporation wastewater
                 treatment plant  - Sistersville, West Virginia.   (Printed,
         with modifications, through the courtesy of the Union Carbide Corpoation.J
Winnipeg, Manitoba  (UNOX)

     One of the more attractive oxygen-
activated sludge plants now in operation
is located at Winnipeg, Manitoba, Canada.
This 12-mgd (0.53-cu m/sec) treatment facil-
ity was designed to operate over a wide air
temperature range (100°F in summer to -50°F
in winter) and is, therefore, totally
housed with the exception of the covered
UNOX reactor.
         The plant utilizes a conventional flow
    scheme to treat municipal wastewater.  Pri-
    mary clarification is utilized ahead of a
    two-train, three-stage/train, oxygenation
    reactor having overall dimensions of 120 ft
    long x 60 ft wide x 19.5 ft deep (36.6 m x
    18.3 m x 5.9 m ).  The reactor's SWD is 16
    ft (4.9 m).   Mixed liquor flow is evenly
    divided between two 110-ft (33.5-m) diam-
    eter final clarifiers.  The SWD of the finals
    is 10 ft (3.0 m).  As with most recently-
                                           537

-------
                       TABLE 17.  OPERATING AND PERFORMANCE DATA FOR
                         UNION CARBIDE SISTERSVILLE OXYGEN SYSTEM
                                                                 Operation
         Parameter
Design
Aug. 1975
Dec. 1975
          Influent Flow  (mgd)*                 4.3
          Aeration Detention Time, Q  (hr)      3.5
          F/M Loading
             (kg BOD5/day/kg MLVSS)            0.85
          Secondary Clarifier Overflow
            Rate  (gpd/sq ft)t                 600
          MLSS  (mg/1)                         5000
          Return Sludge TSS (%)                2.0
          Reactor  Influent (mg/1)
                           BOD5               370
                           TSS               <100
          Secondary Effluent (mg/1)
* 1 mgd = 0.44 cu m/sec
t 1 gpd/sq ft = 0.041  cu m/day/sq  m
$ High sludge return rate
                 3.6
                 4.2

                 0.75

                 502
                4500
                 1.0*

                 425
                  75
                 4.1
                 3.7

                 0.90

                 572
                3900
                 2.0

                 339
                 103
BOD5
TSS
50
<100
25
70
20
43
constructed circular clarifiers, rapid
sludge removal equipment was provided
rather than the older plow-type scrapers.
Primary and waste activated sludges are
mixed and centrifuged before undergoing
incineration.  The flow diagram for the
plant is given in Figure 17.

     The UNOX system components selected
for Winnipeg include surface aerators and
bottom mixers for oxygen dissolution and a
10-ton/day (9.1-metric ton/day) PSA oxygen
gas generator and 14-ton (12.7-metric ton)
liquid oxygen backup tank for oxygen supply.
Considerable difficulty has been experi-
enced with the operation of the PSA com-
pressor.  This machine was initially out-
fitted with internal clearance pocket un-
loaders.  These unloaders did not function
properly resulting in the imposition of un-
due stress on and excessive wear of com-
pressor bearings and bushings.  Frequent
outages were necessary to overhaul the
worn parts.  Eventually in late 1975, the
compressor was completely rebuilt and the
clearance pocket unloaders replaced with
suction pocket unloaders.  Except for one
subsequent unscheduled outage due to a
heater failure, the compressor has worked
well since then.

     System start-up occurred in September
1974.  No process related difficulties have
   been encountered.  Operation at cold mixed
   liquor temperatures down to 10°C has not
   induced growth of filamentous organisms or
   any other noticeable sludge settling prob-
   lems.   In early 1975, official one-month
   performance tests were conducted with only
   one reactor train in service and with both
   reactor trains in service.  Both final
   clarifiers were used during each test.  The
   results of the tests are documented in
   Table 18.  In each case, although the aer-
   ation detention time was less than and the
   F/M loading higher than design, effluent
   BOD5 and suspended solids concentrations
   were significantly lower than required by
   design stipulations..
               ACKNOWLEDGEMENTS

        Information on oxygen systems in
   various stages of implementation was
   supplied by the Union Carbide Corporation;
   Air Products and Chemicals, Inc.; and the
   FMC Corporation.  Case history data and
   flow diagrams for UNOX plants in operation
   were provided by the Union Carbide Corpor-
   ation.  Case history data and pertinent
   diagrams for the OASES plant at Fairfax
   County; Virginia, were extracted from the
   final report draft (5) (publication pending)
   for U. S. EPA Contract No. 68-03-0405.
                                           538

-------
           PSA GENERATOR 12 TPD
   PRE-CHLORINATION
               AGRRITED     PRIMARY
               CHAMBER   CLARIFIERS
                                            LOX STORAGE
                                                UNOX REACTOR
INFLUENT
            BAR

                   | GRIT    PRIMARY!
          SCREENS  I I            • ---
SLUDGE
                                           FINAL CLARIFIERS (2)
         i  SLUDGE HOLDING TANK   JWASTE
         *                          JSLUDGE
                                                            RECYCLE SLUDGE
        j -^- CENTRA!
                              MIXED
                             SLUDGE
                             BASKET CENTRIFUGE
                                             CHLORINATION

                                                          ]


                                                   EFFLUENT
            TO MAIN PLANT INCINERATOR
              Figure  17.   Flow  diagram  of Winnipeg,  Manitoba wastewater treatment
                plant.   (Printed, with modifications,  through the courtesy of
                               the Union Carbide Corporation.)
Process design and equipment criteria for
and visual representations of the MAROX
process were taken from FMC Corporation
advertising literature (4), supplemented
by information derived from personal
communications with FMC.   Progress reports
and other information on file at the U. S.
EPA's Municipal Environmental Research
Laboratory for Grant No.  S803910 formed
the basis of the discussion of Metropolitan
Denver's MAROX demonstration project.
Flow and dimensioned diagrams of the Denver
MAROX test bay were reprinted from an FMC
project bulletin (6).

     The assistance of staff members of the
                   above three firms who contributed in
                   supplying the above described information
                   is gratefully acknowledged, including
                   Ruth Fauth, Robert Kulperger, David Sorensen,
                   Michael Lutz, Randy Dievendorf, and Ronald
                   Grader of Union Carbide; O.Roy Langslet
                   of Air Products and Chemicals; and Duane
                   Parker and W. Phillip Key of FMC.  Special
                   thanks is extended to Ms. Fauth who spent
                   many days collecting and verifying oxygen
                   plant status data.  The cooperation of
                   Richard Kaptain, Assistant Plant Manager
                   for the City of Decatur, Illinois, in
                   providing additional details for the Decatur
                   UNOX case history is also appreciated.
                                           539

-------
                       TABLE 18.  OPERATING AND PERFORMANCE DATA
                         FOR WINNIPEG, MANITOBA OXYGEN SYSTEM
                                                               Operation
          Parameter
                                              1 Reactor Train *    2  Reactor  Trains
                                     Design      Jan. 1975           Apr. 1975
Influent Flow (mgd)*
Aeration Detention Time, Q (hr)
F/M Loading
(kg BOD5/day/kg MLVSS)
Secondary Clarifier Overflow
Rate (gpd/sq ft)t
MLSS (mg/1)
Return Sludge TSS (%)
Reactor Influent (mg/1)
BOD5
TSS
Secondary Effluent (mg/1)
BOD5
TSS
12
1.74

0.46

630
5000
2.2

133
100

25
30
8.5
1.23

0.99

446
5950
1.9

244
290

20
17
13.4
1.59

0.62

704
5100
1.6

150
193

17
13
* 1 mgd = 0.044 cu m/sec
t 1 gpd/sq ft = 0.041  cu  m/day/sq m
$ Both final clarifiers in  service
 2.
 3.
           REFERENCES

Albertsson,  J.  G.,  McWhirter,  J.  R.,
Robinson, E. K.,  and Vahldieck, N.  P.,
"Investigation of the Use of High
Purity Oxygen Aeration in the
Conventional Activated Sludge  Process,
Water Pollution Control Research
Series Report No. 17050 DNW 05/70,
Federal Water Quality Administration,
Cincinnati,  Ohio, May 1970.

 Brenner, R. C.,  "Summary Description
 of Oxygen Aeration Systems in the
 United States,"  Proceedings of the
 Second U. S.-Japan Conference on
 Sewage Treatment Technology,
 Cincinnati, Ohio,  December 1972.

 Brenner, R. C.,  "EPA Experiences in
 Oxygen-Activated Sludge," Prepared
 for Office of Technology Transfer
    Design Seminar Program, U. S.
    Environmental Protection Agency,
    Cincinnati, Ohio, October 1974.

4.  FMC Corporation, "FMC Pure Oxygen
    Wastewater Treatment in Open Tanks,"
    FMC Bulletin 8000-A, Itasca, Illinois,
    1976.

5.  FMC Corporation, "FMC Pure Oxygen
    System at Metropolitan Denver Sewage
    Disposal District No. 1," FMC Project
    Report 8000.1, Itasca, Illinois, 1976.

6.  McDowell, C. S., and Giannelli, J.,
    "Oxygen-Activated Sludge Plant
    Completes Two Years of Successful
    Operation," Draft Report for
    Contract No. 68-03-0405 with Air
    Products and Chemicals, Inc., U. S.
    Environmental Protection Agency,
    Cincinnati, Ohio, Publication Pending.
                                            540

-------
APPENDIX A.  OXYGEN-ACTIVATED SLUDGE PLANTS IN
           OPERATION AS OF JUNE 1976


1.

2.

3.
4.
5.
6.

7.
8.
9.
10.
11.
12.
13.
14.
15.
16.

17.
18.
19.
20.
21.

22.
23.
24.
25.
26.
27.
28.
29.
30.
31.

32.
33.
34.
35.


1.
Location
USA
Alton Box Board -
Jacksonville, Fla.
Baychem Corp. , Chemagro
Div. - Kansas City, Kan.
Brunswick, Ga.
Chaska, Minn.
Chesapeake Corp. West Point, Va.
Container Corp. -
Fernandino Beach, Fla.
Decatur, 111.
Deer Park, Tex.
Denver (#2), Colo.
Detroit (#1) , Mich.
Fairfax County, Va.
Fayetteville, N.C.
Fibreboard Corp. - Antioch, Calif
Ft. Myers, Fla.
French Paper Co. Niles, Mich.
Gulf States Paper Corp.
Tusaloosa, Ala
Hamburg (#1), N. Y.
Hercules, Inc. Wilmington, N.C.
Hollywood, Fla.
Jacksonville (#1), Fla.
Lederle Laboratories Div. of
American Cyanamid-Pearl River, N.Y.
Littleton, Colo.
Morganton , N.C.
Morrisville, Pa.
Newtown Creek New York City, N.Y.
North Lauderdale, Fla.
Quail Valley, Tex.
Speedway, Ind.
Standard Brands - Peeksville, N.Y.
Union Carbide Corp. - Marietta, Ga.
Union Carbide Corp. - Sistersville,
W. Va.
Union Carbide Corp. Taft, La.
Weyerhauser Corp. Everett, Wash.
Wyandotte, Mich.
Yuba City, Calif.
TOTAL
Canada
Winnipeg, Manitoba
Installed
Design 02 Supply
Flow Capacity
(mgd)* (tons/day)f

6

4.32

10
1.25
16.25
25

17
5
10
300
14
14
16
5
0.8
10

1
1
36
5
1.5

1.5
8
4.6
20
2
1.5
7.5
1
1.26
4.33

3.8
3
100
7
664.61

12

25

50

16
1.25
34
50

17
6
7.5
180
10
18
35
9
1
30

0.5
15
50
20
15

0.5
26
4
14
1
2
4
5
1
15

88
25
60
21
856.45

10
Appli-
cation*

I-PP

I-C

M
M
I-PP
I-PP(b)

M
M
M
M
M
M
I-PP(b)
M
I-PP
I-PP

M
I-C
M
M
I-PH

M(d)
M
M
M
M(d)
M
M
I-FP
I-C
I-C

I-PC
I-PP
M
M


M
02 Dis-
solution
System§

UNOX (A)

UNOX (A)

UNOX (A)
OASES (A)
UNOX (A)
UNOX (A)

UNOX (A)
UNOX (A)
MAROX (R)
UNOX (T)
OASES (A)
OASES (A)
UNOX (A)
UNOX (A)
UNOX (A)
UNOX (A)

UNOX (A)
UNOX (A)
OASES (A)
UNOX (A)
UNOX (A)

UNOX (A)
UNOX (A)
UNOX (A)
UNOX (T)
UNOX (A)
UNOX (A)
UNOX (A)
UNOX (A)
UNOX (A)
UNOX (A)

UNOX (T)
UNOX (A)
UNOX (T)
UNOX (A)


UNOX (A)
Supply
System01

CRYO

CRYO

PSA
LIQ
CRYO
CRYO

PSA
PSA
LIQ
CRYO
LIQ
CRYO
PIPE
PSA
LIQ
PSA

LIQ
PIPE
CRYO
PSA
PSA

LIQ
PSA
PSA
PSA
LIQ
PSA
PSA
LIQ
LIQ
PIPE

PIPE
PIPE
PSA
PSA


PSA
                      541

-------
APPENDIX A, Continued
             Location
  Design
   Flow
  (mgd)*
                                                  Installed
                                                  02 Supply
                                                  Capacity
                                                 (tons/day)t
Appli-
cation
02 Dis-
solution
System§
                                                                                   Supply
                                                                                   System"
1.   Electro Chemical Industrial  Co.  -      2.64     n.d.**    I-PC
    Ichihara City
2.   Gotsu Plant   Katano City              0.73     n.d.      M
3.   Ikuta Plant -Kawasaki City             0.61     n.d.      M
4.   Ju jo Paper   Kushiro City               1.59     n.d.      I-PP
5.   Kasuga Plant   Oita City               0.26     n.d.      M
6.   Mitsubishi Chemical Industries         1.9      n.d.      I-PC
7.   Nissho Kayaku Petrochemical             0.74     n.d.      I-PC
    Complex - Oita City
8.   Oji Paper   Kasugai City              18.5      n.d.      I-PP
9.   Oji Paper   Tomakomai City            13.2      n.d.      I-PP
10. Sanyo Kakusaku Pulp - Iwakuni City     0.89     n.d.      I-PP
11. Showa Neoprene   Kawasaki City         0.79     n.d.      I-SR
12. Sumitomo Chemical   Ichihara City      0.79     n.d.      I-PC
13. Uenodai Plant, Japan Housing Corp.      0.52     n.d.      M
    Kamifukuoka City
14. Yakult Pharmaceutical Industries -     0.19     n.d.      I-PH
    Osaka City                           _

    TOTAL                                 43.35
                                UNOX (A)

                                UNOX (A)
                                UNOX (A)
                                UNOX (A)
                                UNOX (A)
                                UNOX (A)
                                UNOX (A)

                                UNOX (A)
                                UNOX (A)
                                UNOX (A)
                                UNOX (A)
                                UNOX (A)
                                UNOX (A)
                                                                                   n.d.<
                                                                                   n.d.
                                                                                   n.d.
                                                                                   n.d.
                                                                                   n.d.
                                                                                   n.d.

                                                                                   n.d.
                                                                                   n.d.
                                                                                   n.d.
                                                                                   n.d.
                                                                                   n.d.
                                                                                   n.d.
                                                                       MAROX (R)    n.d.
 *1 mgd = 0.044 cu m/sec

 i'l ton/day = 0.907 metric  ton/day

 + I-C = Industrial-Chemicals
  I-FP = Industrial-Food Processing
  I-PC = Industrical-Petrochemical
  I-PH = Industrial-Pharmaceutical
  I-PP = Industrial-Pulp §  Paper
  I-SR = Industrial-Synthetic Rubber
  M = Municipal
  (b) - Conventional 02 treatment  plus
        black liquor oxidation
  (d) = Conventional 0^ treatment  plus
        sludge digestion
aerobic
                                               §MAROX = FMC Corp.
                                                OASES = Air Products  § Chemicals,  Inc.
                                                UNOX = Union Carbide  Corp.
                                                (A) = Surface aerators (with  or without
                                                      bottom mixers)
                                                (F) = Fixed active diffusers
                                                (R) = Rotating active diffusers
                                                (T) = Submerged turbines

                                               ^CRYO = On-site liquid oxygen  gas
                                                       generation
                                                LIQ = On-site liquid  oxygen storage  and
                                                      vaporization
                                                PIPE = Pipeline transport  of  oxygen  gas
                                                       from a nearby  off-site oxygen
                                                       generating facility
                                                PSA = On-site pressure swing  adsorption
                                                      oxygen gas generation

                                               **n.d. = no  data.
                                           542

-------
                    APPENDIX B.   OXYGEN-ACTIVATED SLUDGE PLANTS UNDER
                                CONSTRUCITON AS OF JUNE 1976
             Location
Design
 Flow
(mgd)*
 Installed
 02 Supply
 Capacity
(tons/day)t
        02 Dis-      02
Appli-  solution   Supply
cation^: Systems    System1*
     USA

 1.  Appleton Papers Div. of  N.C.F.
    Appleton,  Wise.
 2.  Baltimore, Md.
 3.  Baton Rouge, La.
 4.  Broken Arrow, Okla.
 5.  Cedar Rapids, Iowa
 6.  Chicopee, Mass.
 7.  Cincinnati, Ohio
 8.  Crown Zellerbach Corp.
    Antioch, Calif.
 9.  Dade County (North), Fla.
 10. Danville, Va.
 11. Denver  (#1), Colo.
 12. Detroit  (#2), Mich.
 13. Dow Chemical Co.   Plaquemine,  La.
 14. Dubuque, Iowa
 15. Duluth, Minn.
 16. East Bay Municipal Utility  District
    (#1) - Oakland, Calif.
 17. East Bay Municipal Utility  District
    (#2) - Oakland, Calif.
 18. Euclid, Ohio
 19. Exon Chemical Co. - Baton Rouge,  La.
 20. Fairbanks, Alaska
 21. Fond du Lac, Wise.
 22. Ft. Lauderdale, Fla.
 23. Harrisburg, Pa.
 24. Hillsboro, Ore.
 25. Hopewell, Va.
 26. Hot Springs, Ark.
 27. Jacksonville (#2), Fla.
 28. Kittanning, Pa.
 29. Lewisville, Tex.
 30. Littleton/Englewood, Colo.
 31. Longview Fiber   Longview,  Wash.
 32. Louisville, Ky.
 33. Loxahatchee, Fla.
 34. Mahoning County, Ohio
 35. Miami, Fla
 36. Middlesex, N.J.
 37. Minneapolis, Minn.
 38. Mobile, Ala
 39. Mosinee Paper Corp. - Mosinee,  Wise.
 40. Muscacine, Iowa
 41. Nekoosa Papers, Inc. - Port
    Edwards, Wise.
 42. New Orleans, La.
 43. North San Mateo, Calif.
44. Pensacola, Fla.
45. Philadelphia (Southwest), Pa.
46. Pima County, Ariz.
  6.5
  1.5
    14
     1.5
I-PP    UNOX  (A)   PSA
70
16
4
33
15.5
1.2
5.5
60
24
72
600
12.7
16
43.6
120
75
12
3.5
120
17
50
10
100
33
80
450
69
26
80
250
M
M
M(d)
M
M
M(Z)
I-PP
M
M
M
M
I-C
M
M
M
UNOX (A)
UNOX (A)
UNOX (A)
UNOX (A)
UNOX (A)
UNOX (A)
UNOX (A)
OASES (A)
UNOX (A)
UNOX (A)
OASES (T£A)
UNOX (A)
OASES (A)
UNOX (A)
UNOX (T)
CRYO
PSA
LIQ
CRYO
PSA
CRYO
PSA
CRYO
PSA
CRYO
CRYO
PIPE
CRYO
CRYO
CRYO
        MAROX (R)  PIPE
22
9
8
11
22
35.4
15
57.63
12.1
5
1.5
6
20
30
105
4
4
55
120
1
28
6
13
35
122
8
24
210
25
28
35
13
26
55
50
9
100
11.5
16
1
7
21
40
100
9
7
80
450
1
26
13
80
52.8
140
10
40
90
22
M
I-PC
M(d)
M
M(n)
M
M
M
M
M
M
M
M
I-PP
M
M(n)
M(n)
M
M(d)
M
M
I-PP
M
I-PP(b)
M
M
M(n50)
M
M
UNOX (A)
UNOX (A)
UNOX (A)
UNOX (A)
OASES (A)
UNOX (A)
UNOX (A)
UNOX (A)
UNOX (A)
UNOX (A)
UNOX (A)
UNOX (A)
MAROX (R)
UNOX (A)
UNOX (T)
UNOX (A)
UNOX (A)
UNOX (A)
UNOX (T)
MAROX (F)
UNOX (A)
UNOX (A)
UNOX (A)
UNOX (A)
OASES (A)
UNOX (A)
OASES (A)
UNOX (A)
UNOX (A)
PSA
CRYO
PSA
PSA
CRYO
CRYO
PSA
CRYO
PSA
PSA
PIPE
PSA
CRYO
CRYO
CRYO
PSA
PSA
CRYO
CRYO
LIQ
PSA
PSA
CRYO
CRYO
CRYO
PSA
CRYO
CRYO
PSA
                                            543

-------
r\L 1 J_.11 J./ J. J\. LJ y ^_iV^llt,_LlH^n-«vJ. 	 	 	 — ^^_
Installed
Design 02 Supply 02 Dis- °2
Flow Capacity Appli- solution Supply
	 Location 	 .
47. St. Regis Paper Co. Tacoma, Wash
48. Salem, Ore.
49. Shell Oil Co. - Norco, La.
50. Springfield, Mo.
51. Sunkist Growers, Lemon Products
Div. Corona, Calif.
52. Tahoe/Truckee, Calif.
53. Tampa, Fla.
i f
54. Tauton, Mass.
55. Thilmany Pulp § Paper Co.
Kaukauna, Wise
56. Tonawanda, N.Y.
57. Two Bridges, N.J.
TOTAL
Mexico
1. Fundidora Steel Co. Monterrey
Europe
1. ARA BIRS II, Switzerland
2. Bayer-Elberfeld Dusseldorf,
Germany
3. Copenhagen, Denmark
4. Palmersford, England
5. Union Carbide Belgium Antwerp,
Belgium
TOTAL
Japan
1. Mitsubishi Chemical Industries
Kitakyushu City
2. Mitsui Toatsu Chemicals
Takaishi City
3. Tokiwa Sangyo Owari Asahi City
TOTAL
*1 mgd = 0.044 cu m/sec
tl ton/day = 0.907 metric ton/day
tl-C = Industrial-Chemicals
I-DS = Industrial-Dyestruffs
I-FP = Industrial-Food Processing
I-PC = Industrial-Petrochemical
I-PP = Industrial-Pulp 5 Paper
I-S = Industrial-Steel
M - Municipal
(b) = Conventional 02 treatment plus
liquor oxidation
(mgd)* (tons/day) t cation* Systemi System*
34
26.5
4.3
30
1.75

8
51
8.4
22

30
7.5
2339.58

13.7

18
1.8

110
1.2
0.71

131.71

3.09

1.71

3.7
8.50









black
(d) = Conventional 02 treatment plus aerobic
sludge digestion
(n) = Conventional 02 treatment plus nitrification
(03) Conventional 02 treatment plus effluent
ozonation
(Z) = Treatment of Zimpro supernatant

only

40
36
50
36
50

4
120
20
10

32
6
3328.3

12.7

20
50

160
2
16

248

n.d.**

n.d.

n.d.

§MAROX
OASES
UNOX
(A) =

CF) =
CR) =
(T) =

<*CRYO
LIQ =
PIPE
PSA =

**n.d.
I-PP UNOX (A) CRYO
M UNOX (A) PSA
I-PC UNOX (A) CRYO
M(03) UNOX (A) PSA
I-FP UNOX (A) CRYO

M UNOX (A) PSA
M(n) UNOX (A) CRYO
M(n) UNOX (A) CRYO
I-PP UNOX (A) PSA

M UNOX (A) CRYO
M UNOX (A) PSA


I-S UNOX (A) PIPE

M UNOX (A) PSA
I-C UNOX (A) CRYO

M UNOX (A) CRYO
M(n) UNOX (A) PSA
I-C UNOX (A) PSA



I-DS UNOX (A) n.d.**

I-PC UNOX (A) n.d.

I-PP UNOX (A) n.d.

= FMC Corp.
= Air Products 5 Chemicals, Inc.
= Union Carbide Corp.
Surface aerators (with or
without bottom mixers)
Fixed active diffusers
Rotating active diffusers
Submerged turbines

= On-site cryogenic oxygen gas
generation
On-site liquid oxygen storage
and vaporization
= Pipeline transport of oxygen
gas from a nearby off-site
oxygen generating facility
On-site pressure swing adsorption
oxygen gas generation
= no data
544

-------
                     APPENDIX C.  OXYGEN-ACTIVATED SLUDGE PLANTS
                             BEING DESIGNED AS OF JUNE 1976


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.




12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.

37.
38.

Location
USA
Amherst, N.Y.
Augusta, Me.
Baldwinsville, N.Y. ,
Clay, N.Y.
Clinton, N.C.
Concord, N.C.
Dade County (South), Fla.
Easton, Pa.
Greenville, S. C.
Hamburg (South Towns), N.Y.
Hampton Roads Sanitary District, Va.
(a) Army Base
(b) Atlantic
(c) Boat Harbor
(d) Lamberts Point
Hannibal , Mo .
Holyoke, Mass.
Houston, Tex.
Indianapolis (Belmont) , Ind.
Indianapolis (Southport) , Ind.
Kansas City, Kan.
Kaukauna, Wise.
Lebanon, Pa.
Los Angeles (Hyperion) , Calif.
Los Angeles County (JWPCP) , Calif.
Maryland City, Md.
Montgomery County, Pa.
Monticello, N.Y.
Murfreesboro, Tern.
New Rochelle, N.Y.
Orlando, Fla.
Passaic Valley, N.J.
Philadelphia (Northeast), Pa.
Philadelphia (Southeast), Pa.
Red Springs, N.C.
Sacramento, Calif.
San Francisco, Calif.
South Cobb County, Ga.
Sussex County, Del.
Tri-Municipal Sanitary District -
Poughkeepsie, N.Y.
York, Pa.
Texas City, Tex.
TOTAL
Design
Flow
(mgd)*

24
8
9
10
3
25
40
10
5
12

19
36
26
37
4.25
22
200
125
125
54
6.1
8
330
500
4
10
6
8
14
24
300
150
100
1.5
150
180
24
8
14

8
7.5
2647.35
Design
C>2 Supply
Capacity
(tons/day) t

40
9
19
10
9
80
130
14
8
14

21
40
30
42
9
22
305
180
180
80
13
24
340
500
7
14
6
13
16
50
1000
100
80
5
200
100
40
11
9

13
11
3794
Appli-
cationt

M
M
M
M
M
M
M
M
M
M

M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M

M
M

* 1 mgd = 0.044 cu m/sec
t 1 ton/day = 0.907 metric ton/day
* M = Municipal
                                           545

-------
             CURRENT RESEARCH RELATED TO HEAT CONDITIONING OF WASTEWATER SLUDGE

             B. V.  Salotto,  J.  B.  Parrel1,  J.  E.  Smith,  Jr.,  E.  Grossman, III
                          Municipal Environmental Research Laboratory
                                   Cincinnati,  Ohio  45268
                                          ABSTRACT

     Low and high temperature heat treatment  of sludge produce liquors which are easily
dewatered but create other problems.   High temperature - high pressure processes are
costly, energy intensive, and less safe to operate than are low temperature processes.
However, low-temperature processes produce liquors which need further treatment and they
add to the overall cost of the heat treatment process.  Current research is aimed at
finding economical, energy-saving, processes  to treat and recycle heat treatment liquor.
It is also aimed at developing heat treatment processes which are less energy intensive
but attain the same degree of oxidation as occurs  in a high temperature heat treatment
process.  In the first case laboratory conventional anaerobic treatment of the liquor has
been found to be a satisfactory method of treatment under low loading conditions; however,
a limiting factor is the liquid throughput rate.   Data from operation of 3 lab digesters
indicate that at solids retention times of less than 10 days, some provisions must be made
for return of biomass to the system,  otherwise washout may occur.   Data are also presented
which would seem to indicate a new and novel  approach to low temperature heat treatment
of sludge.   It is known as the Puretec WETOX  process.   Pilot plant results indicate the
achievement of high oxidation rates equivalent to  high temperature-high pressure, heat
treatment systems.  Other advantages  are claimed such as potential for heat and byproduct
recoveries.
                INTRODUCTION

     One of the most controversial  processes
being employed in the wastewater treatment
industry today is that of thermal sludge
conditioning.   The application of heat under
pressure (300 to 500°F and 150-400  psig) for
protracted periods conditions  the sludge by
causing profound changes in its nature and
composition.   Sewage sludges are essentially
cellular material containing intracellular
gel and extracellular zoogleal slime of
equal amounts of carbohydrate  and protein.
The action of heat is to break open the
cells and release the mainly proteinaceous
protoplasm.   The heat also breaks down the
protein and zoogleal slime, producing a
dark brown liquor consisting of soluble
polypeptides,  ammonia nitrogen, volatile
acids and carbohydrates (1).   Generally,
the end results of this conditioning and
"pressure cooking" step are a  heat  treated
sludge liquor which requires some sort of
handling and a residue of considerably
increased dewaterability.  The magnitude
of these two effects is the subject of a
large amount of debate.  The purveyors of
heat conditioning equipment claim that
after conditioning virtually no chemical
conditioning of the sludge is required for
dewatering, that it dewaters at a very high
rate, and that the cake solids produced
are sufficient to permit autogenous
incineration with recovery of sufficient
waste heat to drive the heat conditioning
process.  Further they claim little dif-
ficulty in handling the heat treated sludge
liquor.  The critics of heat treatment
disagree with all these claims and note the
following reported analyses of cooking
liquor: (2)
                                            546

-------
           BOD5 = 5000 to 15000 mg/1
           COD  = 10000 to 30000 mg/1
        Ammonia = 500 to 700 mg/1
     Phosphorus = 150 to 200 mg/1

About 20 to 30% of the liquor's COD has been
found not biodegradable in a thirty-day
period.   While the volume of cooking liquor
from an activated sludge plant will amount
to 0.75 to 1.0% of the wastewater flow; on a
BOD and solids loading basis, the liquor can
represent from 30 to 50% of the normal
loading on the aeration system from settled
sewage.   The critics also point to the
mechanical and odor problems that have oc-
curred at plants like Colorado Springs,
Colorado; Chattanooga, Tennessee; and
Speedway, Indiana.  Then some plants like
Kalamazoo, Michigan, have found that the
costs of heat treatment have rapidly
escalated and treatment schemes had to be
installed to handle the processes' liquor.

     It is possible by operating at even
higher temperatures and pressures in the
presence of oxygen to accomplish a high
level of organic destruction by the process
of wet air oxidation.  Operating conditions
range from 450 to 600°F and from 800 to
1800 psig depending upon the degree of
oxidation required.  This process normally
does not require external heating for
sustaining combustion once it is started.
Equipment includes grinders, high pressure
pumps, heat exchangers, high pressure react-
ors and separators.  The end products of
wet air oxidation processes are a carbona-
ceous ash and sludge liquor.  Criticisms of
this process are similar to those of the
low pressure and low temperature system but
include safety along with serious operating
and maintenance difficulties.  The pollutant
concentration of the resultant cooking
liquor stream varies according to the degree
of treatment and the particular sludge
involved.  Typical concentrations are: (3)

          COD = 10000 to 20000 mg/1
          BOD < 14000 mg/1
      Ammonia = 500 to 1000 mg/1
       Solids 5 2.5%
           PH = 4 to 4.8

     Because of the controversy surrounding
the two thermal sludge processes, EPA has
been conducting research to further
characterize heat treated sludge liquor
and evaluate methods for treating it.  This
paper will report on these efforts.  Further
the paper will report on a new wet air
oxidation process, which seeks to eliminate
some of the disadvantages of the older
system.  This new process may also
facilitate the recovery of metals from
sludge.  As such the types and quantities
of metals in sludge will be discussed
along with the feasibility of their
recovery.

       LIQUOR FROM LOW TEMPERATURE
         (< 400°F) HEAT TREATMENT

Anaerobic Treatment

     Probably the major disadvantage of
heat treatment of sludge is the concen-
trated supernatant that is produced.  If
the BOD discharged from a wastewater
treatment plant is not to be increased,
more treatment capacity is needed.  For
the activated sludge process, this means
a larger aeration basin, greater air
demand, and more biological sludge to be
processed.  An alternative approach is to
treat the sludge anaerobically.  Anaerobic
treatment reduces BOD with a much smaller
increase in biomass than occurs with
aerobic treatment, no power cost for air
compression is incurred, and usable fuel
gas is produced.  Treatment can be carried
out by using conventional anaerobic
digestion or an anaerobic filter (4).
Both of these methods have advantages.
Since most plants that are using heat
treatment previously used digestion,
digesters are generally available for use.
The anaerobic filter is probably the
better choice if new construction is
required.  Research has been commenced in
our laboratory on both of these approaches,
but only the anaerobic digestion approach
is far enough along for presentation of
preliminary results.

     In order to measure such things as
gas production and COD destruction under
different loading conditions, three small
laboratory anaerobic digesters were set
up, each containing 3.5 liters of digesting
material in a 4 liter digesting bottle.
Figure 1 shows a schematic picture of one
of the digesters.  Provision was made to
maintain temperature constant, to stir the
contents of the digester with a magnetic
stirrer, and to collect and measure each
day's production of gas.  Not shown in the
figure is a gas analyzer apparatus to
measure C02 content of the gas mixture.
                                            547

-------
Data were collected so as to be able to
determine or calculate such items as load-
ing rates, COD, BOD, volatile solids
destruction and gas yield.

     At first all three digesters were fed
150 ml of heat treatment liquor each day
for 12 weeks.  Thus, all three digesters
were operated at the same loading  rate.
A supply of heat treatment liquor  was
obtained from a local sewage treatment
plant which heat treated its sludge by the
low pressure Zimpro process.  Each day
150 ml of digesting liquor was removed
from each digester and analyzed for COD,
BOD, total and volatile solids, pH, and
Thermometer
     Inlet
Heating
Tape
 \ Magnetic
 \  S t i r r e r
                        Figure 1. Bench Scale Anaerobic Digester.
                                           548

-------
the like.  The hydraulic detention time  for
all three digesters  was 24 days.

     The manner  of withdrawing digesting
liquor is of  interest.   In all cases, the
digester was  thoroughly mixed just before
the withdrawal was made.   This procedure
is equivalent to the withdrawal method
used for conventional sludge digestion.
A portion of  the active biomass is with-
drawn with the digesting liquor.  This
procedure is  suitable provided the
residence time in the digester is high
enough so that "washout" of the biomass
does not occur.   It  may be possible to
push anaerobic digestion of supernatant to
very high rates  if biomass is returned to
the digester, or is  not removed by allow-
ing settling  before  withdrawal.  This
latter procedure will be tested in a later
phase of the  investigation.

     Some preliminary results of the
digester study have  been obtained.  Table 1
lists average characteristics of the heat
treatment liquor feed.   It should be
pointed out that the more settleable solids
were allowed  to  settle and the supernatant
stored before feeding the digesters.  This
was done so that the liquor might more
nearly resemble  the  filtrate derived from
vacuum filtration of a heat treated sludge.

                 TABLE 1

AVERAGE CHARACTERISTICS OF HEAT TREATMENT
   LIQUOR FEED (TO ANAEROBIC DIGESTERS)
PARAMETER

    pH

ALKALINITY

TOTAL SOLIDS

VOLATILE SOLIDS
    COD

    BOD

    TKN

    NH3
VOLATILE ACIDS

PHOSPHORUS
 UNIT
pH Unit

mg/1 CaCO,
mg/1
mg/1
mg/1
mg/1
mg/1 ACETIC
mg/1
AMOUNT

 5.6

 640

 0.55

 79

 6200

 2440

 590

 240

 1340
 40
                           As the data  indicates, the percent  total
                           solids is  low (0.55%).  Note that the  pH is
                           low as is  the alkalinity.  This was  of some
                           concern because in normal digestion  these
                           values are higher.   As might be expected,
                           COD and BOD  are high although heat  treat-
                           ment liquors  are often much higher.  The
                           nitrogen and  phosphorus values are  shown
                           to indicate  that these essential nutrients
                           are present  in sufficient amounts to insure
                           good digestion.

                                Data  for all 3 digesters operating at
                           the same loading rate were so similar  that
                           the tabulation shown in Table 2 is  typical
                           of all 3 digesters.  This simply indicates
                           that very  little variation occurred.   The
                           excellent  agreement of results among the
                           three digesters gives confidence that
                           differences  in performance noted in  later
                           tests when operating parameters for the
                           digesters  are different will be the effect
                           of the changed conditions and not lack of
                           reproducibility within the units.

                                               TABLE 2
                                  DIGESTER OPERATION: OPERATING PARAMETERS
                                    AND ANALYSES OF DIGESTED LIQUOR*
OPERATOR                 UNIT             AMOUNT

FEED RATE               ml/day               150
  pH                   pH Unit               7.0
ALKALINITY               mg/1 CaCOj            1910
VOLATILE ACIDS            mg/1 ACETIC            63
TEMPERATURE                °C               33+0.2
TOTAL SOLIDS               %                0.33
VOLATILE SOLIDS             %                54.5
COD/BOD                 mg/1              2160/220
DETENTION TIME            DAYS                24
LOADING RATE, VS          Kg/m /day            0.174
VOLATILE SOLIDS REDUCTION     °,                59
GAS YIELD,  PER
  VOLATILE SOLIDS DESTROYED  m gas/Kg VS DESTROYED   0.95
  VOLATILE SOLIDS ADDED     m3gas/Kg VS ADDED      0.62


  'Average results of three digesters


     A comparison  of the analyses of the
feed (Table  1)  and the product (Table 2)
shows that pH increased  to a normal value
of 7.0,  alkalinity increased to 1900 mg/1,
and volatile  acids dropped to a low value.
These data show a  good operating  digester.
Variations of the  properties of the digested
liquor with time are presented in Figure 2.
As can be seen,  pH was quite stable  around
7, whereas alkalinity and volatile acids
fluctuated somewhat during the 12 week
period.
                                              549

-------
 _ 1900--
 5 1700--
   -1500
            LOADING RATE: 0.17 Kg VS/m3/DAY

            DETENTION TIME: 24 DAYS
                    TIME, WEEKS
                                          O
                                          <
                                          I
      Figure 2. Characteristics of Digested Heat
             Treatment Liquor- Unit 1.

      During the  last  12 week phase  of the
study, each digester  was  operated at  dif-
ferent loading rates  in which  300 ml,
450 ml, and 600  ml of heat  treatment  liquor
was fed daily to the  3 digesters.   Un-
fortunately, an  accident  occurred with  the
digester being fed 600 ml of liquor per day
so that no data  can be presented for  that
digester.  Table 3 shows  results of digest-
er operation at  the 300 and  450 ml  feed rate
after a run of 12 weeks compared with
operation of 150 ml for the  other 12  week
period.  Note that efficiency  of the
anaerobic process decreases  as the  loading
rate  increases.  Less COD,  BOD, or  volatile
solids are being destroyed  as  the loading
rate  increases.  Note also  that gas yield,
% C02, and volatile acids change with
changing loading rate.  Surprisingly, no
adjustment of pH or addition of alkalinity
was needed for digester operation.
Alkalinity built up to approximately
3000 mg/1 at the higher rates.

     These studies will continue at higher
loading rates to determine at  what  point
digester failure occurs.  Comparisons will
be made against  operation in which  biomass
is retained in the digester, to determine
the increase in  throughput rate that  can be
achieved with this mode of operation.
Aerobic and Physical-Chemical Treatment

     Studies in Great Britain have  indicat-
ed that heat treatment liquor can be
                                                                   TABLE 3
                                                      DIGESTER OPERATION AT DIFFERENT LOADING RATE
                                                             (DIGESTED SUPERNATANT)
                                                                           LOADING RATES, ml/DAY
OPERATOR
pH
ALKALINITY, mg/I
TOTAL SOLIDS, °-i
VOLATILE SOLIDS, %
COD, mg/1
BOD, mg/1
DETENTION TIME, DAYS
VOLATILE SOLIDS LOADING, Kg/m3/day
COD/BOD REDUCTION, %
GAS YIELD
m3gas/Kg VS DESTROYED
m3gas/Kg VS ADDED
% C02 GAS MIXTURE
VOLATILE ACIDS, mg/1
150
7.0
1910
0.33
54
2160
222
24
0.174
65/91
0.95
0.62
22
63
300
7.2
3310
0.40
61
3600
660
12
0.657
68/87
0.82
0.52
28
114
450
7.1
3130
0.44
64
4510
1040
8
0.985
60/80
0.61
0.39
29
410
reduced  in  BOD  by the activated sludge
process  and by  trickling filters.  Corrie,
in a relatively recent publication (2),
reports  considerable success in which
treatment by  the activated sludge process
is followed by  adsorption on activated
carbon.  By this procedure both BOD and COD
are reduced.  Typically,  biological
processes are not very effective in reduc-
ing the  COD of  heat  treatment liquors.
Corrie's procedure will be evaluated at
Lake County,  Ohio, where a heat treatment
unit has been installed under an EPA grant
(5).   At Lake County,  the effectiveness of
high lime treatment  of heat treatment
liquor will also be  evaluated.   Unfortunate-
ly, these studies have not been commenced
as yet because  of unusual difficulties
encountered in  starting up the heat treat-
ment unit.

A NEW APPROACH  TO HIGH TEMPERATURE OXIDATIVE
              SLUDGE PROCESSING

Puretec Wet Oxidation Process

     Oxidation  of water-based sludges at
high temperatures in the presence of air
was pioneered by the Zimpro Division of
Sterling Drug.   Although several instal-
lations were  made  (e.g.,  Chicago,  Wheeling,
Akron), Zimpro  has had its  greatest com-
mercial success  with  low  oxidation units
(<400°F).  The  primary disadvantage of the
high  temperature  units has  been the high
temperature (>500°F)  and  high pressure
(ca.  1600 psi)  conditions  of operation.
                                             550

-------
     In the Zimpro process, air and sludge
are admixed and pumped through a vertical
unmixed reactor.  Numerous studies have
indicated (6) that agitation improves
reaction rate of multiphase processes.
However, mechanical problems for stirring
high pressure reactors are formidable.
The Resource Recovery Systems Division of
the Barber-Colman Company has developed a
processing system, the Puretec Process,
and equipment that seems to overcome these
difficulties.  Operating temperatures are
about 450°F and pressures about 600 psi.
The U.S. EPA is financing a grant to the
City of Philadelphia to investigate the
Puretec Process at their Northeast
Wastewater Treatment Plant on a sufficient-
ly large scale to accurately determine
process costs, claimed heat recovery
benefits, and achievable sludge destruc-
tion. (7)

The  Philadelphia  Puretec  Installation

     The Puretec  WETOX unit, Model 6-54,
can  treat a  sludge flow of  3000 gallons per
hour or 16 tons of dry solids per day.(8)
In the  process, oxidation of liquid
waste is carried  out continuously at  430°F
and  600 psig  in an acidic medium
 (3 g/1  H2S04).  The oxidation proceeds  in
a horizontal  autoclave containing 6 com-
partments with  individual stirring in  each
compartment.  A process flow diagram  is
shown in Figure 3.  Macerated sludge  is
                    pumped  through  a  liquid and vapor phase
                    tube-in-tube heat exchanger and into the
                    front end  of the  reactor.   The sludge is
                    mixed with compressed  air,  and reacted in
                    the  first  chamber from which it overflows
                    successively into the  several  following
                    compartments undergoing nearly complete
                    oxidation.  Acid  addition  as well as stir-
                    ring enables a  high  rate of oxygen transfer
                    to the  sludge causing  a rapid  destruction
                    of organic matter.   Sulfur compounds are
                    oxidized to sulfates.   In  the  final  com-
                    partment liquid and  vapor  phases are
                    separated  and conducted separately to heat
                    exchangers for  thermal energy  exchange with
                    incoming sludge.   After cooling the  vapor
                    phase and  the liquid phase are let down to
                    atmospheric pressure.   At  this point a
                    variety of post-treatment  steps may  be used
                    to purify  the effluent side-streams  such as
                    the  lime treatment step shown  in Figure 3.

                    Pilot Plant Results  at Irvine,  California

                         Some  impressive results have been
                    achieved with the 4-10 model,  20 gallon/hr
                    pilot plant Puretec  unit at Irvine,
                    California, the location of the Barber-
                    Colman  Company  Research Lab.   Figure 4
                    shows good improvement in  COD  reduction
                    versus  speed of agitation.   Note that at
                    high rpm after  a  reaction  time of 40
                    minutes one obtains  an 80  percent reduction
                    in COD.  Figure 5 shows the increase in
                    COD  destruction as a function  of acid
                                                         VAPOR EFFLUENT
RAW
SEWAGE
SLUDGE
       MACERATOR
            LET-DOWNC
          NEUTRALIZER
          pH 7
                  CLARIFIER
        LIQUID PHASE
            HEAT     f
         EXCHANGER  f

         LJUUUt
                                                         LIQUID EFFLUENT
                         VAPOUR
                        PHASE HEAT
                        EXCHANGER
         LIME FEED
TO PRIMARY
 TREATMENT
                 M in in
        WETOX REACTOR
          TO PRIMARY
          TREATMINT
NEUTRALIZER
pH 7
                                                CLARIFIER
                               FILTER
                            CLARIFIER
            NEUTRALIZER  STERILE
             pH 10.5-11    SOLIDS
BOILER:
START UP
ONLY
                 COMPRESSOR

                 LIME RECOVERY PROCESSOR
                    TO LIME FEED
     Figure 3. Process Flowsheet of the Wetox Unit. A Lime Treatment System is added on to Further Purify
            the Wetox Effluents. The Combined System (Wetox Plus Lime Treatment) is Registered Under
            the Trade  Name of Puretec System.
                                             551

-------
Q
O
VJ
z
o
^-
u

o
uj
QC
h-
Z
LU
{J
    80
    70 —
60
    50
    40
    30
    20
     10
                                  X
                  I
                                U nagitated
                                250 rpm

                              A 750 rpm

                              Q] 1500 rpm
                                     I
      0      10     20    30    40    50    60
    TIME AFTER INJECTION OF SLUDGE, MINUTES

         Figure 4. Effect of Agitation in Wetox.

addition.  The effect of the acid is to
shorten  the reaction  time.  The usual dose
of 1^2864 is 3 g/l; higher  doses, as shown
in Figure 5, do not materially affect the
reaction time.

Advantages Claimed for the Puretec Process
(8)

     No  scale or corrosion problems
corrosion is inhibited  in  the process by
  250001-
<* 20000
01
E 15000
Q
O
u
  10000
   5000
             OPERATING CONDITIONS 450°F - 600 psi
                               • 0 g/l H2SO4


                               X 3 9/1 H2SO4

                               O t> g/l H2SO4
               15       30      45
                 TIME IN MINUTES
                                        60
     Figure 5. COD Reduction of Orange County
             Sanitation District Primary Sludge.
using titanium in piping and  valves  and by
lining the inside of the reactor  with lead
and acid-resistant brick.  The  chief ad-_
vantage here is that corrosion  due to Cl
or SO^  ions is prevented.  Acid  also
prevents scaling in the reactor or in
piping.

     No odor or noise problems    the use of
adequately dispersed oxygen in  an acidified
medium results in a rapid oxidation  of
sulfur and nitrogen-bearing compounds to
sulfate and ammonia.  The reaction does
not form the intermediate organic compounds
which tend to be malodorous in  conventional
processes.  Raw primary or unstabilized
sludge is ordinarily extremely  offensive;
however, under the Puretec oxidizing
conditions very little odor is  present.
Carefully muffled low speed compressors,
which supply the high pressure  air,
specially designed high pressure  sludge
pumps, and the design of the  let  down
valves all combine to minimize  the noise
level usually associated with operation of
heat treatment units.

     The Puretec WETOX process  is com-
petitive   analysis of costs  of the  process
indicate a figure of $45-50 per ton  of dry
solids; this cost has not been  adjusted by
credits as a result of by-product recover-
ies.  Adjustment downward as  a  result of
credits could materially lower  the overall
cost of sludge treatment and  disposal.

      FEASIBILITY OF METALS RECOVERY

Concentration of Metals in Sludge

     Before recovery of metals  can be
discussed, it is important to establish
concentration levels in order to  determine
whether recovery is feasible.  It is well
to note that quantities to be processed and
concentrations can be well below  the normal
levels considered to be practical for metal
refining operations, because  there  is a
credit to be taken for reduction  of
potential hazard and disposal costs  of the
residue.

     Fortunately, considerable  information
has been collected on the concentrations
of metals in sludge.  The Ultimate  Disposal
Section of the Municipal Environmental
Research Laboratory's Wastewater  Research
Division in Cincinnati has had  an ongoing
program in which sludges  from various
treatment plants around the United  States
                                            552

-------
are analyzed.   Results  have been published
by Salotto et al  (9).    Average con-
centrations of  13 metals are shown in
Table 4.  It can be  noted in Table 4 that
the geometric mean is closer to the median
value than the  arithmetic mean.  This
indicates that  a  logarithmic mean distribu-
tion is a good  estimate of the type of
distribution of metal concentrations.  This
in fact is the  case  for all metals examined,
and is illustrated by data for zinc in
Figure 6.  The  implication of a logarithmic
mean distribution, when coupled with a
large logarithmic standard deviation or
"spread", is that there will be a fairly
large number of plants  with concentrations
substantially in  excess of the median.
This indicates  that  the median concentra-
tion is probably  too low a figure to use in
estimating the  practicality of recovery,
but a number substantially higher should be
used.

      .400-.
                    TABLE 4 (See Reference
            AVERAGE CONCENTRATIONS OF METALS
                IK DIGESTED SLUDGE

          (ALL FIGURES MS/KG* DRY SLUDGE BASIS)
>-
u
Z .300-
^U
D
O
LU
Of
LL.
.200-
LU
>
1—
<
_J
^ -100-












































































            2.25  2.55 2.85 3.15 3.45  3.75 4.05  4.35
              LOG Q PPM CONCENTRATION

     Figure 6. Histogram of Zinc in Digested Sludge.
Metal Recovery by  the  Puretec WETOX Process

     As mentioned  earlier,  because of the
use of sulfuric  acid  in the Puretec WETOX
process, the potential  for  metal recovery
looks quite good.   Dr.  W. Martin Fassell,
vice-president and developer of the
process, in his  article "Sewage Sludge at
a Profit" (10),  has reported on tests by
Barber-Colman on recovery of metals from
ash after wet-oxidation.  The effect on
the original level of acid  addition on the
percent of the metal  remaining in sludge
METAL
SILVER
BORON
CADMIUM
CALCIUM
CHROMIUM
COBALT
COPPER
MERCURY
MANGANESE
NICKEL
LEAD
STRONTIUM
ZINC

ARITHMETIC
MEAN STD.DEV.
+
250 230
!+30 310
75 10U
36,500 23,800
1,860 1,920
350 220
1,590 1,670
10 18
1,300 2,290
680 620
2,750 2,350
520 670
I*, 210 3,600
I
GEOMETRIC
MEAN STD.DEV.
t X
190
380
1*3
31,100
1,050
290
1,270
1.99
1.58
2.1*7
1.77
3.22
1.88
1.95
6.51 2-3<*
1*75
530
2,210
290
2,900

3.67
1.88
1.82
2.70
2.1(O

MEDIAN
yyf>
VALUE
100
350
31
30,000
1,100
< 100
1,230
6.6
380
1*10
830
175
2,780

 * A MG/KG  PPM.
 <  LESS THAN
treated by the  Puretec process is shown in
Table 5.  It  is  interesting to observe
from these data  that  increasing amounts of
acid did not  necessarily dissolve more of
the metals, in  fact,  very little lead,
silver and titanium were dissolved out of
the ash.  Evidently the ion products of
insoluble forms  of these elements were
sufficiently  low that dissolution was not
possible.  On the other hand, copper,
cadmium, and  zinc are quite soluble, and
afterwards can  easily be recovered by
precipitation as sulfides according to the
claim of Dr.  Fassell  (10).   At any rate,
it would seem, because of the presence of
an acid side  effluent, that the potential
for metal recovery is quite good.
           TABLC 5 (See Reference 10)

           PERCENT Of METALS PRESENT TN
       WET OXIDATION ASH VERSUS ACID ADDITION
METALS
WT.%
COPPER
LEAD
ZINC
CADMIUM
SILVER
IRON
TITANIUM
PH
H SO ADDITION TO SLUDGE FEED
GRAMS PER LITER
0
93
100
100
97
98
98
100
5.0
6
66
90
66
50
94
91
100
3.5
12
53
77
44
38
87
92
100
1.8
18
7
77
0
0
88
65
100
1.1
                                             553

-------
               SUMMARY

     Low pressure heat treatment, a sludge-
conditioning process that has seen almost
explosive adoption by wastewater treatment
plants in the United States, solves the
sludge dewatering problem in most cases,
but creates nearly as many problems as it
solves.  One of its serious drawbacks is
the creation of a concentrated recycle
liquor.  It is anticipated that there will
frequently be a need to separately treat
this concentrated liquor to reduce the load
on the treatment plant.  Aerobic and
physical-chemical means have been demon-
strated to be effective for separate
treatment but they are costly and require
manpower to operate.  Anaerobic processes
are worth considering as an alternative
because they are typically less labor and
power  intensive.  The present investigation
demonstrates that conventional digestion
satisfactorily reduces BOD of heat treat-
ment liquor.  Continuing studies will be
directed towards achieving higher treatment
rates  by modified anaerobic digestion by
recycling biomass, and by the anaerobic
filter.
     High temperature oxidative processes
for sludge disposal have been poorly ac-
cepted because of cost and extreme
processing temperatures and pressures.
The Puretec process claims to avoid these
extremes by use of a stirred reactor, for
which  high contact efficiency is claimed.
A  demonstration at the City of Philadelphia,
sufficiently  large to demonstrate economics
of performance, will be carried out with
EPA support.  The unique configuration of
the reactor and the use of acidic con-
ditions offers the possibility of recovery
of heat, byproduct  streams such as ammonia
and acetic acid and some metals.

              ACKNOWLEDGEMENT

     The authors wish to acknowledge
Mrs. Patricia Tutt, Physical Science Aid,
for her very  valuable assistance in the
anaerobic digester  study of heat treatment
liquor.  We also wish to acknowledge the
help of Dr. W. Martin Fassell, Vice-
President,  Barber-Colman Company, who gave
us permission to use pilot plant data and
loaned us slides for the presentation.
References

1. Brooks,  R.B.,  "Heat Treatment of Sewage
    Sludge,"  Water  Pollution Control  (G.B.)
    69,  221  (1970).
2.  Corrie, K.D., and Wycombe, R.D.C.,
    "Use of Activated Carbon in the Treat-
    ment of Heat Treatment Plant Liquor,"
    Water Pollution Control (G.B.) 71, 629
    (1972).

3.  Fischer, W.J., and Swanwick, J.D.,
    "High Temperature Treatment of Sewage
    Sludges," Water Pollution Control  (G.B.)
    70_, 355 (1971).

4.  McCarty, P.L., "Anaerobic Treatment of
    Soluble Wastes" in Advances in Water
    Quality Improvement, edited by Glazer
    and Eckenfelder, University of Texas
    Press, Austin  (1968).

5.  EPA Grant 11010 OKI, "Porteous Process
    for Heat Treatment of Sludge," Grant
    awarded to Lake County, Ohio, Sept.
    1971.   (Project officer, B.V. Salotto,
    EPA, Municipal Environmental Research
    Laboratory, Cincinnati, Ohio 45268).

6.  Parrel1, J.B., and Haas, P.A.,
    "Oxidation of Nuclear Grade Graphite
    by Nitric Acid and Oxygen," IECC
    Process Design and Development 6_,  277
    (July 1967).

7.  EPA Grant S-803644-01-1, "Puretec
    Wet-Oxidation of Municipal Sludge,"
    Grant awarded to the Philadelphia  Water
    Department, Philadelphia, Pennsylvania,
    May 30, 1975.  (Project officer,
    B.V. Salotto, EPA, Municipal Environ-
    mental Research Laboratory, Cincinnati,
    Ohio 45268).

8.  Seto, P., "Evaluation of the Barber-
    Colman WETOX Process for Sewage Sludge
    Disposal," Training and Technology
    Transfer Division (Water), EPS,
    Ottawa, Canada, KIA OH3, Project No.
    73-5-6, May 1975.

9.  Salotto, B.V., Grossman, E., and
    Farrell, J.B., "Elemental Analysis of
    Wastewater Sludges from 33 Wastewater
    Treatment Plants in the United States,"
    in Pretreatment and Ultimate Disposal
    of Wastewater Solids, Rutgers
    University, May 21-22,  1974, EPA
    Report No. 902/9-74-002.

 10.   Fassell,  M.,  "Sludge Disposal  at a
      Profit?"  Municipal  Sludge Management,
      Barber-Colman Company, 1882 McGaw Ave.,
      Irvine,  California  92705.
                                             554

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                     EPA's RESEARCH PROGRAM IN SEWAGE SLUDGE COMBUSTION

                                       R. A. Olexsey
                         Municipal Environmental Research Laboratory
                                  Cincinnati, Ohio  45268
                                         ABSTRACT

     EPA's research program in the area of thermal decomposition of sewage sludges ad-
dresses the problems of increased sludge production, energy shortages, pollutant emissions,
and cost.  In the current fiscal year, EPA is supporting a number of projects in the areas
of conventional incineration, starved-air incineration, and pyrolysis.  The purpose, ap-
proach, and any significant results achieved to date are discussed for each of the major
ongoing projects in the area of sludge combustion and pyrolysis.  Pre-fiscal 1976 projects
described include an engineering feasibility study on techniques for combined incineration
of solid wastes and sludges, a full scale research investigation of incineration of sludge
with coal, a pilot plant study of sewage sludge pyrolysis, and a full-scale demonstration
of oxygen-enriched starved-air incineration.  Projects tentatively planned for the fiscal
1976 and 1977 program years are outlined and briefly described.
                INTRODUCTION

     EPA's research program in sewage
sludge combustion is directed toward the
development of environmentally acceptable
and cost effective alternatives to ocean
disposal, which is no longer considered
appropriate, and direct land disposal, which
is not always economically or politically
feasible.  Table 1 outlines the projected
growth of incineration as a sludge disposal
medium based on current trends toward on-
site disposal (1).   Because of a number of
external forces exerting pressures on both
the sludge generation and sludge disposal
operations development of effective thermal
disposal techniques is not an easy task.

TABLE 1.   TRENDS IN DISPOSAL OF SLUDGES
          (WEIGHT PERCENT)
Disposal Methods
  Landfill
  Utilized on Land
  Incineration or Pyrolysis
  Ocean
    (Dumping or Outfalls)
1972

  40
  20
  25

  15
1985

  40
  25
  35

   0
                      Foremost among the factors making mat-
                 ters difficult for sludge disposal is the
                 fact that mandated Federal discharge stan-
                 dards require secondary treatment by 1977
                 and no pollutant discharge by 1985 (2).
                 While the implementation of these standards
                 will result in substantial improvements in
                 water quality, an unfortunate by-product
                 will be the production of much larger quan-
                 tities of much wetter, more difficult to
                 dewater sludge.  Table 2 describes this ex-
                 pected growth in sludge generation (1).

                 TABLE 2.   TRENDS IN PRODUCTION OF SLUDGES

1972 1985
Sludge Type
Primary
Secondary
Chemical
Totals
Pop.
(Mill.)
145
101
10

Tons/Yr Pop.
(Mill.) (Mill.)
3.2 170
1.5 170
0.09 50
4.8
Tons/Yr
(Mill.)
3.7
2.5
0.5
6.7

     The production of more and wetter
sludge impacts the second area of concern
in sludge combustion; that is, the increas-
ing cost and decreasing availability of the
auxiliary fuel required to sustain combus-
                                            555

-------
tion in sludge burners.  Table 3 describes
the effects of increased sludge cake mois-
ture contents on auxiliary fuel demand in a
multiple hearth furnace, with 800° F ex-
haust gas temperatures and 75 percent ex-
cess air (3).  Thus, with current dewater-
ing and combustion practices, the trend
toward increased fuel consumption is di-
rectly counter to contemporary efforts at
fuel conservation.

           TABLE 3. ENERGY REQUIREMENTS FOR SLUDGE CAKES

 Cake                   BTU x 10 *  BTU X 10  Gallons of *2
Moisture/  Lbs. Water  BTU x 10   Provided bv  Auxiliary  Pud Oil for
 Solids    Per Ton  Required for  Sludge     BTU    Au.\. Req.
 Ratio    Dry Solids Evap.of Water Solids Ton Requirement  Per Ion
95/5
90/10
85/15
80/20
75/25
70/30
65/35
* Assuming
Heating
38,000
18,000
11 ,333
8,000
6,000
4,667
3,71-1
volatile sol
value of void
97.00
45.95
28.95
20. 42
15.51
11.91
9.49
ids of dry
tile solids
14.70
14.70
14.70
14.70
14.70
14.70
14.70
sludge solids
= 10,500 BTU/
S2.30
31.25
14.23
5.72
0.61
Autogenous
Autogenous
= 701<
'lh volotilcs
572
217
99
40
A




     Thirdly, air pollution emissions regu-
lations and enhanced public sensitivity to
air-quality and public health-environment
interaction tend to create a somewhat hos-
tile local atmosphere for incinerator
siting.  Although an EPA task force on
sewage sludge incineration found that prop-
erly controlled well designed sludge in-
cinerators were not a significant source
of particulate emissions (4), attempts at
incinerator installation are often met by
vociferous public concern about such con-
siderations as heavy metal emissions and
microbiological aerosols.

     Finally, the accelerating cost of in-
cineration is the essential consideration
in projecting the future for this option.
The following listing notes that incinera-
tion is a high cost disposal technique
relative to alternative means of disposal
(1973 costs)  (5).

                               Total Costs
     Method                     ($/Dry Ton)

1. Disposal as liquid soil
   conditioner                      20
2. Dewatered  sludge as soil
   conditioner                      32
3. Heat drying                      64
4. Lagooning                        15
5. Landfilling dewatered sludge     32
6. Barging to sea                   15
7. Pipeline to sea                  14
8. Incineration                     32
     If combustion is to  remain a viable
sludge elimination alternative,  these
issues of capacity,  fuel, public health and
cost must be squarely addressed.   Toward
this end, the Wastewater  Research Division
of the Municipal Environmental  Research
Laboratory is conducting  and  supporting a
number of applied research, development,
and demonstration projects  in the areas of
conventional incineration processes and
advanced techniques  such  as pyrolysis and
starved-air thermal  degradation.

           ONGOING RESEARCH

     Currently, on a project  by project
basis, the research  program in  sludge
combustion is divided roughly in half be-
tween efforts devoted to  upgrading conven-
tional incineration  and tasks oriented
toward development of new processes.
Project formats range from paper design
concept type studies to full-scale demon-
strations of processes that have been
proven successful in bench  or pilot plant
testing.

Review of Coincineration  Technology

     Sewage sludge incinerators demand sup-
plemental fuel.  Solid waste  incinerators
most often produce excess heat.   Because
of similarities in motivational circum-
stances, cities that practice solid waste
incineration often also incinerate sewage
sludge.  Therefore,  it would  appear to be
a perfectly logical  development that the
two materials be disposed of  in a common
incineration process.  Conceptually at
least, savings would result from decreased
auxiliary fuel demand, capital  economies
of scale, and the need to operate only one
facility.  Figure 1  is an extremely simpli-
fied schematic of a  combined  incineration
system.  In this arrangement, hot flue
gases from a solid waste  incinerator are
used to dry incoming sludge in  a separate
chamber.  The dried  sludge  is then burned
in the same furnace  as the  refuse.

     In spite of the seemingly  irrefutable
logic of combined disposal, the history of
coincineration in the U.S. had  been a study
in failure.  Facilities enjoyed only short
lives and were plagued by operational
problems and high costs.  In  short, co-
incineration, while  relatively  successful
in Europe, had simply not worked in the
United States.
                                            556

-------
                                                      FAN
SOLID WASTE
                             COOLED GAS
       G>
                                         HOT FLUE GAS
                                                                            SLUDGE CAKE
                                                                                  O
                                               DRY SLUDGE
            INCINERATOR
                                                                   SLUDGE DRYER
                          Figure 1. Simplified system for combined incineration.
     To analyze the failure of coincinera-
tion and suggest feasible alternatives,
the EPA, after competitive bidding,  entered
into a contractual arrangement with  the
Roy F. Weston Company of West Chester,
Pennsylvania.  Under the terms of this  con-
tract (EPA No. 68-03-0475), the contractor
would explore the literature, visit  oper-
ating sites in both the U.S.  and Europe,
and perform engineering feasibility  studies
of specific techniques.

     While the final results  of this study
are not yet reported, some conclusions  can
be drawn.   Coincineration was not ap-
proached seriously in the U.S. when  fuel
was abundant and cheap.  Most coincinera-
tion facilities operated through simple
addition of sludge cake to the feed  of  a
solid waste incinerator.  The high moisture
contents of sewage sludges require design
modifications to facilitate pre-drying  of
the sludge feed.  Often, the  refuse  itself
is too wet to burn without supplemental
fuel.

     Some  successes have been achieved.   A
spray dryer-incinerator has operated inter-
mittently  at Ansonia, Connecticut, and  a
rotary dryer at Holyoke, Massachusetts, has
performed  reasonably well.  As can be ex-
pected from any paper type study, starved-
air incineration techniques ranked highly
in the Weston evaluation.
     The final report for the study will
include design specifications for applica-
tion of the most promising techniques to
an existing sewage treatment plant.  Cost
data will be provided and local factors,
such as geography and politics, which might
impact implementation of a combined dis-
posal system will be discussed.

Pulverized Coal as a Dewatering Aid

     One solution to the fuel problem would
be the production of a sludge cake feed
that burns autogenously,  that is, without
auxiliary fuel.  This, of course, can be
accomplished by producing a cake that has
a moisture content that is low enough so
that the latent energy in the sludge solids
is sufficient to evaporate the moisture in
the cake.  A second approach is to increase
the volatile content of the cake to a point
that the cake will support combustion.

     Some previous EPA research work had
shown that incinerator ash could be of sig-
nificant value as a conditioning agent in
vacuum filtration operations (6).  Filter
yield and cake solids content increased
substantially with ash dosages in the
range of from l-.O Ib. ash/lb. sludge solids
to 4.0 Ib. ash/lb. sludge solids.

     While the addition of ash resulted in
improved filter performance, it  also re-
duced the energy content of the  sludge
                                            557

-------
cake because of the increased presence of
inert material in the  filter cake.   An in-
house research project was  initiated to
evaluate the performance of pulverized coal
as a filtration aid.   If the coal  did not
impair the function of the  vacuum  filter,
then the fuel value realized from  the coal
addition could serve to allow the  replace-
ment of costly fuel oil with the less ex-
pensive coal.

     Table 4 compares  the properties of the
coal and sludge used in the filtration
study  (7).  The coal used was mine run
Pennsylvania bituminous coal with  a rela-
tively low sulfur content.  The sludge was
a 1 to 1 by weight mixture  of primary and
waste activated sludge.

TABLE 4.  COMPARISON OF THERMAL PROPERTIES
    Property
Coal
BTU/lb Dry Volatile
Solids
Volatile Solids %
BTU/lb Dry Solids
Sulfur %

14,200
93.6
13,300
0.60

10,500
65-75
7,370
0.60

     Figure 2 emphasizes  the  enhancement of
sludge cake fuel value while  the  filter
yield and final cake solids increased mar-
ginally with coal fines addition  (7).   The
coal dosages monitored were in  the  range of
from 0.1 Ib. coal per Ib.  of  sludge solids
to 0.4 Ib. coal per Ib. of sludge solids.

     Figure 3 describes the magnitude of
coal addition required to achieve autoge-
nous combustion conditions in a multiple
hearth furnace at two significant exhaust
gas temperatures  (7).  The range  of addi-
tion of from 0.1 to 0.2 Ib. coal  per Ib. of
sludge solids that provides the needed
energy represents significant economic sav-
ings over the conventional method of simple
filtration and oil addition.  At  current
prices, coal addition in  the  required range
can accomplish cost reductions  of from $4
to $15 per ton of dry sludge  solids incin-
erated (3,7) .

     Further work is planned  with coal and
ash mixtures as filtration aids.  The pur-
pose of this work would be to reduce the
usage of conditioning agents  such as lime
and ferric chloride.
4000

3000

2000

1000

   0




£  4

   2

   0

  60

  40

  20
                                 _ BTU'S/lb WATER
                                               FILTER YIELD
                                                 7
                                             CAKE SOLIDS
                                                               I
                                                       I
                                  I
                                                              0.1      0.2      0.3     0.4
                                                                COAL DOSE (Ib COAL/lb DSS)

                                                               Figure 2. 'Coal performance.
                                                     BTU'S REQUIRED  ]400°F


                                                     BTLTS REQUIRED @>800°F
                                                            I
                                                                  I
                                           02    0.3
                                                            0.5
                                        COAL DOSE  (Ib COAL/lb DRY SLUDGE SOLIDS)
                              Figure 3. Thermal profile coal conditioned sludge.
                          Full  Scale Incineration with Admixes

                               To  underscore the threat  that  the fuel
                          shortage poses to on-site sludge  disposal
                          systems, EPA recently entered  into  a  re-
                          search grant arrangement with  the Metro-
                          politan  Waste Control Commission  of the
                          Twin  Cities Area (Minneapolis-St. Paul).
                          Under the terms of this grant  (EPA  No.
                          R803927) a series of fuel admixes will be
                          combusted with the sewage sludge  feed to
                                             558

-------
the six dry tons per day multiple hearth
incinerators at the Commission's 24 mgd
Seneca Sewage Treatment Plant.  The plant
is ideal in that the sludge disposal
system consists of two independent and
parallel lines, each including its own
vacuum filter, conveyors, feed apparatus,
and incinerator.  One line will be used as
a control and one line will be used to
test the effects of the various admixes.
The incinerators at Seneca resemble the
model depicted in Figure 4.

                          COOLING AIR DISCHARGE
                           FLOATING DAMPER
                        	    SLUDGE INLET

                    J«g
 FLUE GASES OUT

   RABBLE ARM
 AT EACH HEARTH
   DRYING ZONE
                                  COMBUSTION
                                  AIR RETURN
   COMBUSTION
      ZONE
  COOLING ZONE
                                RABBLE ARM
                                 DRIVE
                    VCOOLING AIR FAN
      Figure 4. Typical section: Multiple
              Hearth Incinerator.

     Tests of from one to four months' dura-
 tion each will be conducted with  various
 fuel additives in place of the normally
 used No. 2 fuel oil.  Fuels will  be lumped
 coal mixed with filter cake, pulverized
 coal mixed with liquid sludge prior to
 filtration, shredded and classified com-
 bustible solid waste,  pelletized  solid
 waste, scrap rubber tires, wood wastes, and
 combinations of fuels.  Data collected dur-
 ing the course of the two-year project will
 include information on operational param-
 eters such as mass balances of sludges and
 fuels, air flow rates, temperature profiles
 over time with changes in feed ratios, ash
 characteristics,  and scrubber water and gas
properties.

     The grant is currently in the hardware
procurement and facilities modification
stage.   Testing work will begin in the
spring of 1976.   The grant work is being
cosponsored by the Wastewater Research Divi-
sion and the Solid and Hazardous Wastes
 Research Division as part of its Wastes-as-
 Fuels  Research program.

 Pilot  Plant Pyrolysis

     Pyrolysis is a process that holds much
 potential  as a disposal technique for or-
 ganic  materials.   Pyrolysis, which is the
 heating  of a material in the absence of
 air, reforms organic materials into lower
 molecular  weight  compounds.   The resultant
 products can be in the form of a gas, a
 liquid fraction,  and a solid char,  all with
 appreciable fuel  values.   Theoretically,
 air pollution is  minimal,  energy recovery
 capacity is high,  and costs  are roughly
 equivalent to those for incineration.

     Pyrolysis had been proven effective  on
 many organic waste materials,  including
 municipal  refuse  (8).   In  order to  explore
 the application of the concept of pyrolysis
 to sewage  sludge  disposal,  EPA entered in-
 to an  interagency  agreement  with the U.S.
 Bureau of  Mines.   Under the  terms of this
 agreement  (EPA No.  IAG-D4-0436)  primary
 sludge, activated  sludge,  sludge blends,
 and mixtures  of sewage sludge  and solid
 waste  were pyrolyzed  at the  Bureau's
 Pittsburgh Energy  Research Center pilot
 plant.   A  diagram  of  the pyrolysis  pilot
 plant  is presented in Figure 5.   Wastes are
 fed into the  batch retort  and  heated by an
 electric furnace.   Tars and  gases are
 cleaned and collected while  the  solid char
 remains in the retort.

     Table 5  summarizes the  yields  of char,
 oil, and gas  obtained from the pyrolysis of
 dried  activated sludge at 500° C  and 900°  C.
 Pyrolysis  of  one ton  of activated sludge at
 900° produced approximately  1000  pounds of
 char,   13000 cubic  feet of gas, and  30 gal-
 lons of oil.   Total energy recovery  was
 over 12.5  million  BTU's per  ton of  feed.

 Demonstration of Oxygen-Enriched  Pyrolysis

     Budgetary  constraints are such  that
 the funding of  full-scale capital-intensive
 demonstration projects  would absorb  all of
WRD's  sludge  disposal  research funds.
Therefore,  in  order to  obtain maximum usage
of the  budgeted funds,  attempts are  made to
involve EPA in  limited testing of existing
 full-scale  facilities.  Such is the  case
with a demonstration  grant awarded  to the
City of South  Charleston, West Virginia.
Under the  terms of this grant  (EPA  No.
                                             559

-------
                               LEGEND
      1. THERMOCOUPLE
      2. ELECTRIC FURNACE
      3. RETORT

      4. TAR TRAP
      5. TUBULAR CONDENSER
                            9.CARBON DIOXIDE SCRUBBER

                            10. CAUSTIC PUMP
                            11. LARGE WET-TEST METER

                            12. DRYING TUBE
                            13. LIGHT OIL CONDENSER
6. ELECTROSTATIC PRECIPITATOR 14. SMALL WET-TEST METER

7. AMMONIA SCRUBBER        15. GAS SAMPLE HOLDER

8. ACID PUMP
                                   SAMPLE COCK FOR
             j M                   H2S AND NH3 TESTS"
                                                             EXCESS GAS
                                                              IS FLARED
                                                                                TO Btu AND
                                                                              sp gr RECORDERS

J'^'A
Ti
^
;

ft

9


W//s

: 3



1
:fc^
a

* 1
5
;



r



WATER
OUT

WAT
N

5
ER


^ T 1
    HEATING
    ELEMENTS
                             ELECTRODES


                         WATER
                           OUT
                                                NaOH NaOH
                       DRAINS
                       Figure 5. Pilot Plant Pyrolysis System.
TABLE 5.  SUMMARY OF YIELDS  FROM  PYROLYSIS
          OF DRIED ACTIVATED SLUDGE


Pyrolysis Temperature  °C       500     900

Yields, Weight Percent of
  Feed
   Char                  '       57.7     54.1
   Gas                          5.8     29.3
   Tar, Oils, Aqueous           25.3     13.9

Yields, Per Ton of Feed
   Char, Ib.
   Gas, cu.ft.
   Tar, Oils, Aqueous, gal.
   Ammonium Sulfate, Ib.

Energy, Million BTU/Ton
  of Feed
   Char                         5.1      4.6
   Gas                          1.9      5.4
   Tar, Oils, Aqueous           4.0      2.6
                       1154     1082
                       2637    13415
                         57.7     29.6
                        103.3     73.4
                                          S803769) dewatered sewage  sludge will be
                                          added to the feed to the  200 ton per day
                                          solid waste oxygen refuse  conversion plant
                                          in that city.  This plant,  described
                                          schematically in Figure 6,  was constructed
                                          to dispose of the municipal solid waste
                                          generated in South Charleston (9).   The
                                          process was developed by  the Union Carbide
                                          Corporation and has the trade name Purox.
/o7
( TON
OXYG
T,

N f^\
\ ( TONS 1
S ^REFUSE'
EN ^
T 1.01
TONS
GAS
1 ••
1 	 -
GAS
CLEANING
TRAIN
1
0.22 TONS 0.03 TONS RECYCLE
0.7 TONS
"FUEL GAS
1
WASTEWATER
0.28 TONS
                                            GLASS AND METAL
                                                  Figure 6. Inputs and products of Purox System.
                                            560

-------
     In the Purox system waste material is
fed into the top and oxygen into the bottom
of a shaft furnace.   In the furnace there
is a combustion zone where the oxygen is
injected and a pyrolysis zone near the top.
In the combustion zone,  the inorganic frac-
tion of the waste material is melted and
exits as a slag.  In the pyrolytic zone
gases are produced from the organic frac-
tion of the feed.  The fuel gas produced
has a heating value of about 300 BTU/SCF.

     The grant work at South Charleston
will be of limited duration with testing
lasting only about four months.  Through
the course of the testing, optimum ratios
of sludge to solid waste will be deter-
mined.  The environmental impacts and eco-
nomic feasibility of codisposal in the
Purox system will be ascertained.  Sludge
addition will begin in the spring of 1976
upon completion of a solid waste reliabil-
ity test.

            PLANNED RESEARCH

     Looking ahead to research that is gen-
erally planned for the next two years, we
see that program emphasis remains on re-
ducing cost and fuel consumption and on
neutralizing the environmental effects of
sludge combustion.  Project mix will in-
clude feasibility, laboratory bench, and
full scale demonstration projects.

     In the next year, which is our fiscal
year 1976, the most significant effort will
be an operational study of the modifica-
tions required to convert an existing
multiple hearth incinerator to pyrolytic
operation.  The widespread utilization of
the multiple hearth furnace for sludge
combustion indicates that the conversion
approach may be the most direct method for
rapid implementation of sludge pyrolysis.

     Also to be funded in 1976 will be a
laboratory study of the feasibility of
steam reformation of liquid sludge and raw
solid wastes in a rotary kiln reactor.
Under this concept, the water from the wet
sludge will serve as a steam medium for the
conversion of the solid organics to a gas
and an ash.  The gas would then be cleaned,
burned, and the spent exhaust used to power
a turbine for electric power generation.

     A third project in the next year will
be an in-house study to characterize the
char from sludge pyrolysis operations so
that applications for this by-product
might be found.  A part of this study will
be an investigation of the use of the char
produced from pyrolysis of solid waste as
a conditioning agent and fuel for sludge
filtration and combustion.

     Project planning for fiscal year 1977
can only be tentative.  A mass and energy
balance may be performed around an existing
sludge incinerator so that the environ-
mental effects of conventional incineration
may be more completely described.  The com-
bined incineration process determined to be
the most favorable through the ongoing
Weston study may be demonstrated.  Further
studies of uses for carbon char from
pyrolysis will be conducted, with the main
emphasis being on the use of char as an
activated carbon with the recovery of
metals from the char as a by-product.
Finally, the costs of sludge pyrolysis will
be compared with the costs for conventional
sludge incineration.

              CONCLUSIONS

     While it is impossible to design and
fund a research program that encompasses
all worthwhile endeavors, it is believed
that the program described herein best
utilizes available funds and best reflects
foreseeable priorities.  Future directions
in combustion research will be dependent on
any shifts in these priorities and on the
magnitude of program funding.

               REFERENCES

1.  Parrel1, J. B., "Overview of Sludge
      Handling and Disposal," in Municipal
      Sludge Management, Proceedings of the
      National Conference on Municipal
      Sludge Management, pp. 5-10, June 11,
      1974.

2.  Federal Water Pollution Control Act
      Amendments of 1972, Oct. 1972.

3.  Hathaway, S. W., and Olexsey, R. A.,
      "Improving the Fuel Value of Sewage
      Sludge," in News of Environmental
      Research in Cincinnati, Nov. 1975.

4.  Environmental Protection Agency Task
      Force Report, "Sewage Sludge Incinera-
      tion," Report No. EPA-R2-72-040
       (Aug. 1972), NTIS PB 211323.
                                            561

-------
5.   Olexsey, R.  A., "Thermal Degradation of
      Sludges,"  in Pretreatment and
      Ultimate Disposal of Wastewater
      Solids,  pp.  127-196, May 21, 1974,
      Report No. EPA-902/9-74-002.

6.   Smith, J.  E.,  Jr.,  Hathaway, S. W.,
      Farrell, J.  B., and Dean, R. B.,
      "Sludge Conditioning with Incinerator
      Ash," Proceedings of the 27th Purdue
      Industrial Waste Conference, Eng.Ser.
      141, Part  2, 911-925 (May 2-4,  1972).

7.   Hathaway,  S. W.,  and Olexsey,  R.  A.,
      "Improving Vacuum Filtration and
      Incineration of Sewage Sludge by
      Addition of Powdered Coal,"  presented
      at 48th Annual  Conference of the
      Water Pollution Control Federation,
      Oct. 9,  1975.

8.   Sanner, W. S., Ortuglio,  C., Walters,
      J. G., and Wolfson,  D.  E., "Conver-
      sion of Municipal and Industrial
      Refuse into  Useful Materials by
      Pyrolysis,"  U.  S. Bureau of  Mines
      Investigation 7428,  Aug.  1970.

9.   "Solid Waste Disposal  Resource Recov-
      ery," Union  Carbide  Bulletin F-3698.
                                           562

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        URBAN STORMWATER MANAGEMENT AND TECHNOLOGY IN THE UNITED STATES - AN OVERVIEW

                                          R. Field
                        Storm and Combined Sewer Section, WRD, MERL
                                Edison, New Jersey   08817
                                          ABSTRACT

     Combined sewer overflows are major sources of water pollution problems, but even
discharges of stormwater alone can seriously affect water quality.  Current approaches
involve control of overflows, treatment, and combinations of the two.  Control may involve
maximizing treatment with existing facilities, control of infiltration and extraneous
inflows, surface sanitation and management, as well as flow regulation and storage.  A
number of treatment methods have been evaluated including high rate screening and micro-
straining, ultra high rate filtration, dissolved air flotation, physical/chemical treat-
ment, and modified biological processes.  A swirl flow regulator/solids separator of
annular shape construction with no moving parts has been highly developed.  High rate
disinfection methods including new disinfectants have been applied.  Promising approaches
involve integrated use of controls and treatment.
                INTRODUCTION

     Control and treatment of stormwater
discharges and combined sewage overflows
from urban areas are problems of increasing
importance in the field of water quality
management.  Over the past decade much re-
search effort has been expended and a large
amount of data has been generated, primarily
through the actions and support of the U.S.
Environmental Protection Agency's Storm and
Combined Sewer Research and Development
Program.  A summary which includes problem
definition and management alternatives will
be presented.

            PROBLEM DEFINITION

     The background of sewer construction
lead to the present urban runoff problem.
Early drainage plans made no provisions
for storm flow pollutional impacts.  Un-
treated overflows occur from storm events
giving rise to the storm flow pollution
problem.

     Simply stated the problem is:

     Iflhin a cMty £ak&> a. bath, what do you.
do uiith tii
-------
                                 ^|  RAW

                                 £52  COMBINED

                                 |  |  STORM
       BOD
                   SS
                             DO
 5X107
                 B  RAW

                 h%4  COMBINED

                 |  |  STORM
   TOTAL COLIFORM
     MPN/100 ml
 TOTAL
NITROGEN
  TOTAL
PHOSPHORUS
Figure 1.  Representative Strengths of
           Wastewaters (Flow Weighted
           Means  in mg/1)

100 times dry-weather flow.  Even separate
storm wastewaters are significant sources
of pollution, "typically" characterized as
having solids concentrations equal to or
greater  than those of untreated sanitary
wastewater, and BOD concentrations approxi-
mately equal to those of secondary efflu-
ent.  Bacterial contamination of separate
storm wastewaters is typically 2 to 4
orders of magnitude less than that of
untreated sanitary wastewaters.  Signifi-
cantly,  however, it is 2 to 4 orders of
magnitude greater than concentrations
considered safe for water contact acti-
vities .

     It  is important to note that there is
no apt description of "typical" combined
sewage or stormwater runoff characteris-
tics due to the variable nature  of  the
rainfall-runoff patterns.  Quality  may
range from super-strong sanitary sewage
during the "first flush" to very diluted
sewage later in the storm.  The  composi-
tion is dependent on a number of factors,
including:  length of antecedent dry
weather, local climatic conditions, con-
dition of the sewerage system and the
nature of the drainage area.

     A few municipal studies can serve to
exemplify the problem.  In Northampton,
England it was found that the total mass
of BOD emitted from combined sewer  over-
flows over a two-year period was approxi-
mately equal to the mass of BOD  emitted
from the secondary plant effluent.  The
mass emission of suspended solids in com-
bined sewer overflow was three times that
of the secondary effluent.

     The relatively poor flow characteris-
tics of combined sewers during dry-weather
when sanitary wastes alone are carried,
encourages settling and build-up of solids
in the lines until a surge of flow  caused
by a rainstorm purges the system.   Studies
in Buffalo, New York have shown  that 20 to
30 percent of the annual collection of
domestic sewage solids are settled  and
eventually discharged during storms.  As a
result, a large residual sanitary pollution
load, over and above that normally  carried
is discharged over a relatively  short in-
terval of time, oftentimes resulting in
what is known as a "first flush" phenomenon.
This can produce shock loadings  detrimental
to receiving water life.  Aside  from the
raw domestic and industrial sewage  carried
in the overflow, non-sanitary urban runoff
in itself is a significant contributor to
the overflow pollution load.  As the storm
runoff drains from urban land areas, it
picks up accumulated debris, animal
droppings, eroded soil, tire and vehicular
exhaust residue, air pollution fallout,
heavy metals, deicing compounds,  pesticides
and PCB's, fertilizers and other chemical
additives, decayed vegetation, corrosion
products, hazardous material spills, to-
gether with many other known and unknown
pollutants.

     A study on a 1.67 sq mi drainage area
in Durham, North Carolina has shown that
after providing secondary treatment of
municipal wastes, the largest single
source of pollution from the watershed is
separate urban runoff without the sanitary
                                           564

-------
constituent.  Additional treatment of
municipal waste could not be expected to
significantly affect the total per acre
yield of organic and suspended solids from
the basin on an annual basis, though it
might be necessary to protect the quality
of watercourses during periods of dry
weather and low stream flow.

     When compared to the raw municipal
waste generated within the study area the
annual urban runoff of COD (as shown in
Figure 2.) was equal to 91 percent of the
raw sewage yield; the BOD yield was equal
to 67 percent, and the suspended solids
yield was 20 times that contained in the
raw municipal wastes.
   2,000 -i
                                MUNICIPAL SEWAGE
                                URBAN RUNOFF
   1,000 -
        NO SEWAGE TREATMENT
                             91% TREATMENT OF
                             MUNICIPAL WASTE
Figure 2.  Annual pollutant  (COD) yield
           from urban land runoff.

     If Durham provided 100 percent removal
of organics and suspended solids from the
raw municipal waste on an annual basis,
the total reduction of pollutants dis-
charged to the receiving water would only
be 52 percent of the COD,  59  percent  of
the ultimate BOD, and only 5  percent  of
the suspended solids.

     During storm flows, dissolved  oxygen
content of the receiving watercourse  was
found to be independent of the degree of
treatment of municipal wastes beyond
secondary treatment.  Oxygen  sag estimates
were unchanged even if the secondary  plant
was assumed upgraded to zero  discharge,
and stormwater discharges  governed  the
oxygen sag 20 percent of the  time.

     Besides the aforementioned conditions
in Durham, certain forms of solid waste
such as beer cans, broken  glass bottles,
garbage, bed springs, shopping carts,  etc.,
find their way into urban  stream beds.
These solid wastes, believed  to be  typical
of urban streams, not only contribute to
lower water quality, but are  aesthetic
pollutants adding to property devaluation
and are a hazard to public safety as  well.
Figure 3. depicts coarse flotables  from a
combined sewer overflow in the Chicago,
Illinois, USA area.
Figure 3.  Coarse flotables from a combined
           sewer overflow, Chicago, IL, USA

              DESIGN CONSTRAINTS

     Precise characterization of the
wastewater is virtually impossible because
of the variability in the character of
storm or combined wastewater and because of
the many physical difficulties in repre-
sentative sample collection.  Also, because
of the intermittency and variability of
stormwater runoff and interrelated system
flows, there is no such thing as an
"average" design condition for storm flow
                                           565

-------
treatment facilities.  Therefore, a process
that performs only when conditions are
right or steady-state, may be too restric-
tive for practical applications.

              CONTROL ALTERNATIVES

     The concept of constructing new sani-
tary sewers to replace existing combined
sewers has largely been abandoned due to
enormous costs, limited abatement effec-
tiveness, inconvenience to the public and
extended time for implementation.  It is
again emphasized that urban stormwater
runoff itself can be a significant source
of stream pollution.  Sewer separation
would not cope with this pollution load.
It is further estimated that the use of
alternate measures could reduce costs to
about one-third of the cost of separation.

What Can Be Done About The Problem?

     The viable control alternatives are
presented.  First there is the problem at
the source, e.g., at the land and streets,
in the collection system, and off-line by
storage.  We can remove pollutants by
treatment and by employing complex or in-
tegrated systems which combine various
combinations of control and treatment in-
cluding the dual-use of dry-weather
facilities.  Second, there is the choice
of how much control or degree of treatment
to introduce.  Thirdly, there is the impact
assessment, public exposure, and priority
ranking with other needs.  The proper
management alternatives can only be made
after cost-effective analysis involving
goals, values, and hydrologic-physical
system evaluations generally assisted by
mathematical model simulations,  pilot-
scale trials, and new technology transfer.

Source Control

     Source Control can be accomplished by
employing porous pavement and upstream
impoundment for flow attenuation; soil
erosion preventative measures; restrictions
on chemicals used for deicing, fertiliza-
tion, pest control, and leaded gasoline;
zoning and land use regulations; and im-
proved neighborhood sanitation practices.
The theory behind source controls is to
limit the supply of contaminants.  The
benefits are not only reduced water pollu-
tion but also cleaner and healthier en-
vironments .
     It is recommended that  the newer and
more promising street cleaning equipment
such as vacuum sweepers, air brooms  and
wet scrubbers be further evaluated and
employed as opposed to conventional  sweep-
ing and flushing methods.  The newer devices
offer benefits in picking up the urban run-
off pollution causing dust and dirt  parti-
cles rather than redistributing them for
aesthetic purposes as the conventional de-
vices do.

Sewerage System Control

     In sewerage or collection system con-
trol the emphasis is on optimizing the
existing collection system.  Measures which
can be used include:

     -Dry-weather flushing to reduce dry-
      weather solids accumulation and
      thereby relieving the  overflow first
      flush.
     -Polymer feed to reduce overflows by
      increasing pipe carrying capacity.
     -Infiltration/Inflow prevention and
      correction.
     -And improved flow regulators or di-
      version devices, e.g., the swirl,
      helical and fluidic types.

     A swirl flow regulator/solids-liquid
separator being demonstrated in Syracuse,
NY, USA is shown on Figure 4.
Figure 4.  Swirl Regulator—Flotables  en-
           trapment during wet-weather
           operation, W. Newell St.,
           Syracuse, NY, USA
                                           566

-------
Figure 5.  is  a schematic diagram.   The de-
vice, of simple annular shape  construction,
requires no moving parts.  It  provides a
                    LEGEND
               InUt Romp
               Flow D.fl.ttor
               S.um Ring
               Overflow Woir and W.ir Plot.

               Spoilm
               Flooiabl.I Trop
               Fowl Sow.r OulUt
               Floor Gutl.ri
 Figure 5.   Isometric View  of  Swirl Regula-
            tor/Concentrator .

 dual function,  regulating flow by  a cen-
 tral circular weir while simultaneously
 treating combined  wastewater by a  "swirl"
 action which imparts liquid-solids separa-
 tion.  The low-flow concentrate is di-
 verted via a bottom orifice to the sanitary
 sewerage system for subsequent treatment
 at the municipal works, and the relatively
 clear supernatant  overflows the weir into
 a central downshaft and receives further
 treatment or is discharged to the  stream.
 The developmental  model in operation is
 shown in Figure 6.   The device is  capable
 of functioning  efficiently over a  wide
 range of 80:1 of combined sewer overflow
 rates, and can  effectively separate sus-
 pended matter at a small fraction  of the
 detention time  required for conventional
 sedimentation or flotation (seconds to
minutes as opposed to hours by conven-
 tional tanks).   The capital cost of the
6.8 mgd Syracuse prototype was $55.000.
O&M is estimated at $2,000/yr.  Swirl
construction cost  curves are presented
in Figure 7.
                                                 Figure  6.   Overhead view of  swirl regulator/
                                                             separator in operation, Labora-
                                                             tory Hydraulic Model,  LaSalle,
                                                             Quebec, Canada
                                                  3  «
                          o (DRAFT} EPA CONTRACT NO. 66-03-0371
                          • SWIRL PROTOTYPE, WEST NEWELL ST.
                           SYRACUSE. NEW YORK, U.S.A.
                           IAS BUILT WITHOUT PUMPING)

                          ° SWIRl PROTOTYPE, WEST NEWELL ST
                           SYRACUSE, NEW YORK, USA
                           {PROJECTED FOR 1007. GRIT REMOVAL
                           BASED ON REFERENCE 9)
                                                                           1007. ORIT REMOVAL
                          90% GRIT REMOVAL
        as 2
        324
 169 8
 645
25S.O
969
339.6  DESIGN FLOW RATE, cu m/min
129.0  DESIGN FLOW RATE, mgd
Figure 7.
Estimated construction cost
curves—swirl  regulator/separa-
tor
Preliminary tests indicate  at  least 50 per-
cent removal of suspended solids  and BOD.
Tables  1.  and 2. contain further  details
on the  Syracuse prototype treatability.

Figures 8.  and 9. containing influent and
effluent pollutographs show total sus-
pended  solids and BOD removed  during a
storm.

     The swirl concept is also being
piloted in Denver, Colorado and Toronto,
Canada.  At Denver it is being used as a
degritter  and at Toronto as a  primary
clarifier.   This work is still ongoing,
however preliminary test results  are very
encouraging.  A helical or  spiral-type
regulator/separator has also been developed
based on principles similar to those of
the swirl  device.  This device is benefi-
                                             567

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                         Table  1.   Suspended Solids Removal
Swirl Concentrator
Mass Loading
kg

Storm No.
02-1974
03-1974
07-1974
10-1974
14-1974
01-1975
02-1975
06-1975
12-1975
14-1975
15-1975
a
For the

Inf.
374
69
93
256
99
103
463
112
250
83
117

Kff
179
34
61
134
57
24
167
62
168
48
21
conventional
SS concentration
inflow.

7
Rem.
52
51
34
48
42
77
64
45
33
42
82
regulator
Conventional Regulator
Average SS
per storm, mg/1

Inf.
535
182
110
230
159
374
342
342
291
121
115
removal
of the foul underflow




Eff.
345
141
90
164
123
167
202
259
232
81
55
%
Rem.
36
23
18
29
23
55
41
24
20
33
52
calculation,
equals

the SS


Inf
374
69
93
256
99
103
463
112
250
83
117
it is
Mass Loading
kg

Underflow
101
33
20
49
26
66
170
31
48
14
72
assumed that the

%
Rem.a
27
48
22
19
26
64
34
27
19
17
61

concentration of the



     Data reflecting negative  SS removals at  tail  end of storms not  included.
"e c
J 0-
< *?
Table 2. BOD REMOVAL li

0.076 -
0.152 -
0.229 -
0.305 -
U[ 1 1 I 1 1 M 1 I 1 1 1 1
1

STORM #1 3/24/75
5 DAY BOD
0 MASS LOADING (INFLU
                            Average BOD
       Mass Loading, kg   per storm, mg/1
 Storm                 %               %
   No.  Inf.    Eff.   Rem.  Inf.  Eff. Rem.
7-1974
1-1975
2-1975
266
97
175
48
30
86
82
69
51
314
165
99
65
112
70
79
32
29
                                                                               « MASS LOADING (EFFLUENTI
                                                                              	FLOW
                              o MASS LOADING (INFLUENT)
                              A MASS LOADING (EFFLUENT)
         7 00 8:00 9 00 10.00 11.00 12:00 13:00 14:00 15:00 16:00 17:00
                       TIME, hrs

Figure 8.  Swirl  regulator suspended  solids
           removal,  W.Newell St.,  Syracuse,
           NY,  USA
        11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00
                    TIME, hrs
Figure 9.   Swirl  regulator  BOD,- removals,
            W.  Newell  St., Syracuse, NY, USA

cial as  its solids separation action is
created  by  only a bend in the sewer line.

     Other  collection system control
methods  are:

     -In-sewer or  in-line storage  and
      routing whereby the intent is to
      assist a dispatcher in routing and
      storing storm flows to make  maximum
      use of existing interceptors and
      sewer line capacity.   The general
      approach comprises remote monitoring
      of rainfall, flow  levels, and some-
                                             568

-------
      times quality,  at selected locations
      in the network,  together with a
      centrally computerized console for
      positive regulation.

     -And lastly,  the  most  common approach
      is off-line  or  external storage with
      concrete tanks used most often.  The
      concept is to capture wet-weather
      flow and bleed  it back to the treat-
      ment plant during low flow dry-
      weather periods.   The results of
      controlling  overflow  by detention
      are shown on Figure 10.  Notice how
      an entire hypothetical overflow
      event at point A is prevented by
      storage with controlled dewatering.
        RAINFALL
     T
             T
T
  RAINFALL
      -OVERFLOW
         s- CAPACITY
       --*--  OF
            PLANT
           »• t
                        RAINFALL
                       •*"| RAINF
                         r\
                                t	TIMED
HYDROGRAPH AT "A"
 WITHOUT CONTROL
                          CONTROLLED
                         HYDROGRAPH AT
                             "A"
Figure 10.  Results of controlling storm
            flow by storage

     Storage facilities possess many of
the favorable attributes desired in storm
flow control:  they are capable of pro-
viding flow equalization; are simple to de-
sign structurally, and operate; respond
without difficulty to intermittent and
random storm behavior; are relatively un-
affected by flow and quality changes; and
frequently can be operated in concert with
regional dry-weather treatment facilities.
Disadvantages of storage facilities in-
clude their large size, high cost, and
dependency on other treatment facilities
for dewatering and solids disposal.  A
3.5 MG asphalt lined storage basin in
Chippewa Falls,  WI, USA eliminated 59 out
of 62 river overflows during the evalua-
tion period.
 Treatment

      The various treatment methods used
 for storm flow include physical and
 physical-chemical,  biological, and disin-
 fection.  These processes or combinations
 of these processes, can be adjuncts to the
 existing sanitary plant or serve as remote
 satellite facilities at the outfall.

      Physical and/or chemical treatment
 processes in many ways are well suited to
 storm flow applications,  particularly with
 respect  to solids removal because of their
 resistance to shockloads  and rapid startup
 and shutdown characteristics.  These pro-
 cesses include sedimentation, dissolved
 air flotation, screening,  filtration,
 carbon adsorption and special swirl separa-
 tion.

      To  reduce capital investments,  demon-
 stration projects have been directed
 towards  operations  approaching the maximum
 loading  boundaries.   Applications include
 their use for pretreatment or roughing,
 for the  main or sole treatment,  and,
 particularly in the case  of microstrainers
 and filters,  as effluent  polishing devices.

     The microstrainer is  conventionally
 designed for  polishing secondary sewage
 plant effluent at an optimum rate of
 approximately 10  gpm/sq ft.   Tests on  a
 pilot microscreening unit  of 23  micron
 aperture in  Philadelphia have shown  that  at
 high influx  rates of 25-30 gpm/sq ft,  sus-
 pended solids  removals in  combined over-
 flows as high  as  90% can be  achieved.
 Since overflows are  not continuous as
 sanitary flows  are  occurring about five
 percent  of the  total time,  a sacrifice of
 screen life  for increased  hydraulic  treat-
 ment rate  is worthwhile.

     A study  in Cleveland  showed  high
 potential  for  treating combined  sewer  over-
 flows by in-pipe  filtration  using anthra-
 filt and  sand  in  a  7  to 8  foot bed.
 Figure 11. depicts  the Cleveland  pilot
 plant.   With the  high loadings of 16 to 32
 gpm/sq ft  surface area, removal  of solids
was effectively accomplished throughout
 the entire depth  of  filter  column.  Test
work showed  suspended solids removal up to
                                         569

-------
Figure 11.  Pilot plant, Cleveland,  OH,
            USA

and exceeding 90 percent and BOD removals
in the range of 60 to 80 percent.  Substan-
tial reductions, in the order of 30 to 80
percent of phosphates, can also be ob-
tained.

     Results from a 5.0 mgd screening and
dissolved-air flotation demonstration pilot
plant in Milwaukee, WI, USA indicate that
greater than 70 percent removals of BOD
and suspended solids are possible.  Find-
ings also revealed 85 to 97 percent re-
duction in phosphate can be achieved as  an
additional benefit, by employing chemical
coagulants.

     Biological treatment of storm waste-
waters must overcome some serious draw-
backs:  (1)  the biomass used to assimilate
the waste constituents must either be kept
alive during times of dry weather; and
(2) once developed, the biomass is highly
susceptible to washout by hydraulic surges
or overload.

     Examples of biological treatment
applications to stormwater include (1) the
contact stabilization modification of
activated sludge, (2) high rate trickling
filtration, (3) bioadsorption using
rotating biological contactors, and (4)
oxidation lagoons of various types.   The
first three are operated conjunctively
with dry-weather flow plants to supply the
biomass and the fourth involves long term
storage of the flows.  With  the  exception
of lagoons, some form of pre-unit  flow
equalization and control is  essential  for
biological processes.

     The most commonly used  disinfectants
under the research program are sodium
hypochlorite, chlorine dioxide,  and  ozone.
Because the disinfectant and contact de-
mands are great in storm flow applica-
tions, due to intense flowrates, current
research centers on high-rate applications
(1) by imparting turbulence, (2) use of
alternative, more rapid disinfectants, and
(3) on-site generation of disinfectants.
Successful results in all these  areas  have
been demonstrated.

Integrated Systems

     By far the most promising approach to
urban stormwater management  is the inte-
grated use of control and treatment  with
an areawide multidisciplinary perspective.

     When a single method is not likely to
produce the best possible answers to a
given pollution situation, various treat-
ment and control measures—as previously
described—may be combined for maximum
flexibility and efficiency.  One such  com-
bination might be:  in-sewer or  off-system
storage for subsequent overflow  treatment
in specifically designed facilities,
followed by groundwater recharge or  re-
covery for water sports and  aesthetic
purposes.  Another combination might be
flow retention with pump or  gravity  bleed-
back to the sanitary sewerage system.

     In all cases the optimum abatement
plan for stormwater overflow pollution
will have to be evaluated separately for
the geographical area in consideration.
Aside from climatological conditions,
terrain, and land uses, choice of control
and treatment will depend on the existing
sewerage system configuration.   For
example, separate systems with large
contributory areas and few overflow  points
present problems and require design
philosophies which differ from those of
systems divided into many subdrainage
areas with individual combined wastewater
outfalls.

     The temporary storage concept,  pre-
viously discussed as a control process,
also provides for a certain  degree of
treatment by settling, for excessive
                                          570

-------
 overflows greater than  the  design storage
 capacity discharging directly to the re-
 ceiving stream.  Likewise,  this settling
 potential for flows less  than design capa-
 city,  together with on-site solids disposal
 and/or controlled dewatering to the receiv-
 ing stream (in accordance with assimilation
 capacity), which are usually overlooked,
 should be definitely considered.

      Another approach in overcoming the
 extreme variation in overflow rates is to
 provide surge facilities prior to the
 storm flow treatment plant  or the munici-
 pal plant.  The surge basin(s)  (or exist-
 ing combined sewers) could  furthermore
 serve a dual function in equalizing not
 only wet-weather flows but  dry-weather
 flows as well.  In this way,  a single
 future treatment system can readily be
 designed for storm and sanitary flow
 conditions.  This could also  assist pre-
 sently overloaded sanitary  plants in
 obtaining more uniform operation.   Short-
 term storage incorporated into the treat-
 ment plant would even out the daily cycle
 of dry-weather flows allowing for more
 efficient use of the treatment process
 over the entire 24 hours.   Equalization
 would permit reduced treatment process
 design capacity.  Further analysis is
 necessary to determine the  most economical
 break-even point between the  amount of
 storage versus the treatment  capacity.
 The designer should recognize the wet-
 weather treatment plant's capability to
 draft  stored flow continuously  while it is
 raining in his evaluation of  the optimum
 surge-treatment system.   Dual-use  wet-
 weather storage and treatment  facilities
 built  in conjunction with dry-weather
 plants  can be used to improve  dry-weather
 treatment capacity and effectiveness
 the vast majority of the time when it is
 not raining.

     The program has fostered various
 schemes  which reclaim storm flows  for
 beneficial purposes  including the  enhance-
 ment of  visual aesthetics, recreation,  and
 water supply.

     Mount Clemens,  MI,  USA has  installed
 a treatment-park system  involving  dis-
 charge of  combined  sewage overflows  into
 a series  of  three  "lakelets" each  equipped
with surface  aerators  (schematic,  Fig-
ure 12.).  Effluents pass from  one pond  to
the next  through microstrainers  and
filters,  and  the final effluent  is chlo-
        COMBINED SEWER
                            COMBINED SEWER
                        64 MGD
        LAKELET NO. 1
            • SETTLING (FOUR DAYS-MAXIMUM STORM)
            • MECHANICAL & NATURAL SURFACE AERATION
            • AEROBIC S ANAEROBIC DIGESTION
            • SCUM REMOVAL
                                         I  I
                                            -
                        I MGD
          MICROSTRAINER
          • MECHANICAL FILTRATION
          • SUSPENDED SOLIDS S BOD REMOVAL
          • ALGAE (PHOSPHOROUS-NITROGEN) REMOVAL
                     (6) 1 MGD
          CHLORINE-CHLORINE DIOXIDE
          • DISINFECTION £ ODOR CONTROL
                        1 MGD
        LAKELET NO. 2    ©
            • NATURAL SURFACE AERATION
            • PHOTOSYNTHETIC OXYGENATION
                        I MGD
        LAKELET NO. 3
            • MECHANICAL & NATURAL SURFACE AERATION
            • PHOTOSYNTHETIC OXYGENATION
                        I MGD
        PRESSURE FILTER
            • HIGH RATE SAND FILTRATION
            • SUSPENDED SOLIDS S BOD REMOVAL
            • ALGAE (PHOSPHOROUS-NITROGEN) REMOVAL
©
CLINTON
RIVER ©
Figure  12.
                                      ©
Schematic diagram of  Mount
Clemens, MI, USA  facility.
rinated.   This  control and treatment
scheme  is  designed to have no adverse
aesthetic  impacts and blend into a  sur-
rounding park development and the waters
are being  reclaimed for recreation  and
reused  for park irrigation.

Computer Assistance

     Mathematical models are needed to
predict complex dynamic system responses
to variable and stochastic climatological
phenomena.

     These models have been developed and
applied at many levels of sophistication
including  EPA's Storm Water Management
Model (SWMM)  which is capable of represent-
ing the gamut of urban runoff conditions
both qualitatively and quantitatively from
the uppermost catchment point to the down-
stream receiving water.
                                             571

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              RESULTS  AND  COSTS

     Detroit  found  the cost  of in-system
controlled  storage  to be  as  low as $0.02
to  $0.04/gal.   This range was approximately
one-tenth the estimated cost for large
•off-line facilities.

     Typical  abatement system construction
costs  are summarized  based on mid-1973
prices.

       Table  3.   TYPICAL  COSTS OF
COMPONENT DEVICES AND OPERATIONS, ENR 2000
                                            TOTAL STORAGE
                                            1.56 mo x S 0.50/oal
                                            = $ 760,000
  In-line  storage
  Off-line storage
 *Physical treatment
 *Physical/chemical
   treatment
    $0.02-0.25/gal
    $0.20-A.75/gal
 $5,000-35,000/mgd

$35,000-80,000/mgd
 ^Biological  treatment  $60,000-80,000/mgd

 *for  a hypothetical  25 mgd plant
     These  data  are  based  on  a very  limited
number  of specific projects;  thus, they
represent only an order  of magnitude
placement.   In extrapolating  these costs
into master plan systems,  such as the  City
of  San  Francisco's (CA,  USA), the totals
frequently  approach  $500-1,000/acre.   It
is  estimated that the national average per
acre cost for sewer  separation would be
$20,000-$30,000  today.   Whereas  a similar
estimate for the control alternatives
would fall  in the neighborhood of
$10,000/acre.

     A  simplified example  will serve to
illustrate  an advantage  of integrated
approaches.   Assume  a design  composite
storm overflow for a combined catchment
area is three hours  long and  the hydro-
graph (Figure 13.a.) is  triangular shaped
with a maximum value of  25 mgd occurring
at  the  end  of the first  hour.  Total
containment  in storage would  therefore
require a capacity of 1.56 MG which  at a
unit cost of  $0.50/gal would  cost $780,000
to  construct.  Similarly a treatment
facility designed for the  maximum flowrate
might cost  $750,000  at $30,000/mgd.  A
10  mgd plant, however, coupled with  a
storage capability of 0.56 MG would  accom-
plish the same objectives  for $580,000 as
illustrated  by Figure 13.b.   Of  particular
importance  is the opportunity for the
treatment plant  to operate at its design
capacity for  a sustained period  of time.
                                                        TOTAL TREATMENT
                                                        25 MGD x $ 30,000/MOD
                                                        = S 750,000
                            Figure 13.  M Soparolo Approach
                                         Storage  or  Treatment
NET STORAGE
0.56 mg X $ O.SO/gn
 TREATMENT
 10 MGD x $ 30,000/MGD = $ 300,000
                                                                             TOTAL $ 580,000
              = $ 280,000
                                   ]_3 .  (b) Integrated Approach

                                        Storage and  Treatment
                              While prototype  installations in
                         operation today are still  relatively few
                         in number, some impressive results have
                         been obtained.  The in-system storage
                         concepts have proven  feasible to operate
                         and maintain with a major  curtailment of
                         overflow occurrences  and durations.   Off-
                         line storage and detention-chlorination
                         facilities are proven performers with
                         additional benefits for backing up over-
                         loaded treatment works innovated.  Storm
                         flow facilities constructed in parallel
                         with conventional dry-weather flow treat-
                         ment plants have introduced dual-use
                         functions improving even dry-weather
                         performance as well as increasing treat-
                         ment capacities during storm periods.

                                         CONCLUSIONS

                              All facts point  to a  real requirement
                         for treating and controlling stormwater
                         runoff and combined sewer  overflows.  In
                         view of the tremendous quantities of
                         pollutants bypassed during rainfall from
                         the combined sewer system,  it does not
                         seem reasonable to debate  whether secondary
                         treatment plants should be designed for
                         80, 85 or 90% BOD or  suspended solids re-
                         moval, when in fact the small increments
                         gained in this range  are completely over-
                                            572

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shadowed by the bypassing occurring at
regulators during wet-weather flow.  During
a single storm event, from 95% to 99% of
the total organic load is attributed to
runoff generated discharges.  On an annual
basis the storm associated organic load
may be from 40% to 80% the total figure.
It has been estimated that detrimental
wet-weather receiving stream impacts can
last for days.

     It is a distinct possibility that
communities may make expensive sewage
treatment plant improvements and still
not achieve water quality goals due to
the impact of urban runoff (or some other
nonpoint source) unless steps are taken
to harmonize land use with water quality
or treat the runoff waters to reduce their
adverse effects on receiving streams.

     Along with planning to upgrade
secondary sewage treatment plants, and
because of possible contravention of stream
standards, we should carefully assess the
potential impact of urban runoff.

     The multi-billion dollar treatment
plant upgrading and expansion program now
going on throughout the country will do
much to alleviate pollution of our waters.
However, means of mitigating the effects
of combined sewers and stormwater must
also be found if we hope to abate the
pollution in an optimal manner.  Wet-
weather standards continue to be promul-
gated.
                                           573

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                    ACTIVATED CARBON FOR MUNICIPAL WASTEWATER TREATMENT
                                    James J.  Westrick
                        Municipal Environmental Research Laboratory
                                 Cincinnati,  Ohio  45268
                                         ABSTRACT

     Full scale use of activated carbon adsorption as a municipal wastewater treatment
process has resulted in part from the early vigorous research efforts of EPA's predecessor
organizations.   Research is continuing in pilot plant operations in Cincinnati and
elsewhere to further understand the process and its implications in the water pollution
control effort.  Completed and ongoing research projects dealing with influence of
chemical pretreatment, pH, nitrate addition,  and breakpoint chlorination are discussed.
The removal of general organic pollutants,  heavy metals and specific organics such as
halomethanes, is described with regard to the studies conducted or sponsored by EPA.   A
brief description of the independent physical-chemical system at Rocky River, Ohio, and
the performance and cost evaluation study of the completed facility are included.
               INTRODUCTION

     The use of activated carbon for
municipal wastewater treatment was one of
the principal results of the research
sponsored in the early days of the Advanced
Waste Treatment group of the U.S.  Public
Health Service.  Research at Harvard,
Pittsburgh, Cincinnati,  Lebanon, Pomona and
Tahoe established the feasibility of
utilizing granular activated carbon beds
for the removal of organic matter from
secondary effluents and regenerating spent
carbon for reuse.  The first full-scale
application of this research was the 7.5
mgd (28,000 cu m/day) advanced waste
treatment facility at South Tahoe, Cali-
fornia.  Here activated carbon was utilized
as the last treatment step in an extensive
train of processes beginning with
conventional activated sludge through two-
stage lime clarification, ammonia stripping,
filtration and finally,  adsorption.   Lime
sludge recalcination and carbon regeneration
were also incorporated.   This pioneering
facility has been on stream since 1968,
producing high quality water for irrigation
and recreational uses.
     Encouraged by the success at Tahoe
and assisted by Research Development and
Demonstration Grant funding, several other
local authorities constructed tertiary
carbon systems at Colorado Springs,
Colorado, Nassau County, New York, and
Piscataway, Maryland.

     A number of studies by private
interests and research sponsored by EPA's
predecessor organizations opened the
possibility of using carbon as an alter-
native to biological systems for secondary
treatment.  Activated carbon was shown to
be effective for the production of high
quality effluent when preceded by efficient
chemical clarification.  A flurry of
feasibility studies followed and several
municipalities opted for systems consisting
of chemical clarification of raw wastewater
followed by activated carbon beds.  Such
systems, called Physical-Chemical  (P-C)
Systems, promised some apparent advantages
when compared to conventional secondary
treatment systems.  These are shown in
Table 1.  The space savings resulted in
the selection of P-C treatment at Rocky
River and Cleveland Westerly.  It is
especially dramatic at Cleveland, where a
                                            574

-------
50 mgd (190,000 cu m/day) P-C system will
be constructed on a 7-acre (3 ha) site,
with room for future expansion.  Other
municipalities chose P-C to best cope with
local conditions, such as unusual raw
wastewater characteristics or high quality
effluent requirements.


   TABLE 1 - FEATURES OF P-C TREATMENT

 1.  Minimum land requirements

 2.  Low sensitivity

 3.  Unaffected by toxic materials

 4.  Flexibility of design and operation

 5.  High organic removal

 6.  High phosphorus removal
 7.  Capability for heavy metal removed


     Because of the relatively high
purchase price of granular activated carbon,
regeneration and reuse of spent carbon is
commonly practiced.  All municipal
regeneration systems currently in use or
planned utilize thermal regeneration
systems wherein spent carbon is raised to a
temperature of ~900°C-1000°C by contact
with hot gases of combustion in a multiple
hearth furnace.  Steam is normally injected
to oxidize the adsorbed organics.

     Whether on-site regeneration is
economic depends upon carbon utilization
rate, the plant size, the delivered cost of
virgin carbon, local labor cost, and
installed cost of regeneration equipment.
On-site regeneration in multiple hearth
furnaces is not feasible at very small
plants, because the smallest fully
automated commercially available multiple
hearth regeneration furnace has a firm
capacity of 3000 Ib/day (1400 kg/day).
Other types of thermal regeneration systems
may be developed in the future which will
allow economic regeneration of spent carbon
at small facilities.  One example is a unit
which uses infrared lamps to heat carbon
passing through a controlled atmosphere on
a continuous conveyor.  Rotary kilns might
also be economic at the small plant size.

     The demonstrated success of granular
carbon regeneration both at Tahoe and in
the sugar industry and uncertainty as to
the feasibility of regenerating powdered
carbon (mean particle size ~ 10-20 y)
favored the development of granular  carbon
over powdered carbon systems  for municipal
wastewater applications.  Powdered carbon
was shown to be effective both  in tertiary
and P-C applications in a series of  pilot
studies sponsored by EPA and  predecessor
organizations.  Pilot scale regeneration
has been successful at several  locations,
and in fact, a 10 T/day (9000 kg/day)
powdered carbon regeneration  system  is
now operated by a carbon manufacturer to
regenerate spent sugar carbon.  Thus,
renewed interest in powdered  carbon  for
municipal use is expected.

   CINCINNATI PILOT PLANT ACTIVITIES

     Several recent projects  have been
conducted at the Cincinnati EPA facility
to learn more about the use of activated
carbon for municipal wastewater treatment.

Effects of Chemical Pretreatment on Carbon
Adsorption (1)

     As suggested earlier, when carbon is
used in the P-C system (no biological
treatment), it is normally preceded by
chemical clarification and sometimes
filtration.  The chemicals used are those
which also precipitate phosphorus, namely
lime or salts of aluminum or  iron.  The
chemical clarification systems have
generally been selected on the assumption
that the type of chemical pretreatment
used would have no effect upon the sub-
sequent adsorption of organics by activated
carbon.  However;  several reports were
published which claimed that  high pH lime
clarification caused alkaline hydrolysis of
high molecular weight organic molecules and
produced a subsequent beneficial effect on
carbon adsorption in terms of effluent
quality and carbon capacity.   In order to
investigate the influence of  chemical
pretreatment on carbon performance,  three
P-C pilot systems were constructed,  operated
with three distinctly different chemical
clarification schemes.   Data were collected
and evaluated with special emphasis given
to carbon performance.

     The three chemical treatments used were

  1.   High lime   690 mg Ca(OH)2/l,pH>ll.5
           neutralized to pH<7 by C02+H2S04

  2.   Low lime - 320 mg Ca(OH)2/l+15 mg
           Fe3+/l, pH ~ 10
                                                 3.  Iron
                 62 mg Fe3+/l, pH 6.0-6.5
                                           575

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A schematic of the iron system  is  shown in
Figure 1.  The lime systems were similar
with the addition of retention  and
neutralization tanks.

     Each chemical clarifier  was followed
by a dual-media  (anthracite-sand)  filter
and a carbon adsorber.  Each  adsorber was
made up  of 5 - 4-in-(10 cm) diameter tubes
in series with a total depth  of 18 ft
(5.5 m)  of Filtrasorb  300  granular carbon.
The application rate was 4 gpm/sq  ft
(10 m/hr) for a total  empty bed contact
time of  34 min.  The systems  were  operated
continuously for eleven months except for
brief shutdowns for minor  mechanical
failures.

     The overall performance of the three
systems is presented  in Table 2.  The
source of raw sewage  for this project was
a 30-in-(76 cm) diameter interceptor sewer
serving a residential-commercial neighbor-
hood.  The sewage  could be described as
weak, partly because  of infiltration
during periods of  rainfall.   There were
some differences in performance of the
three systems based on the removal of the
 Raw Sewage
              Ferric Sulfate
    To Waste
                                                                     s)Denotes sample  point
                              Figure 1.  Flow diagram, iron system.
                          Table 2.  Average performance of P-C Pilot System.
Item
Raw Sewage
Low-Lime System:
Clarifier Eff.
Filter Eff.
Carbon Eff.
Iron System:
Clarifier Eff.
Filter Eff.
Carbon Eff.
High-Lime System:
Clarifier Eff.
Filter Eff.
Carbon Eff.
TOC
'"8/1
59.9

17.4
12.5*
7.1*

14.1
9 . 5*
4.9*

15.9
12.9*
6.2*
% Re-
moval


71
79
88

76
84
92

73
78
90
COD
rag 1 1
215

52.0
36.9*
22.8*

42.2
27.8
17.0*

43.0
36.5*
20 . 8*
% Re-
moval


76
83
89

80
87
92

80
83
90
TSS
mg/1
98

20
7
6

28
12
7

17
9
8
% Re-
moval


80
93
94

71
88
93

83
91
92
P
mg/1
9.2

1.3
0.9
0.9

1 .0
0.3
0.3

0.5
0.5
0.5
7. Re-
moval


86
90
90

89
97
97

95
95
95
Alk.
(mg/1 as
CaC03)
209

165
156
165

54
62
66

209
200
163
Turb.
(JTU)
38

11
5
11

21
13
12

8
4
7
Iron
(mg/1)
0.7

1.3
0.4
0.7

8.2
3.5
2.9




Color
Units



16
7


10
5


14
5
Ca
mg/1 as
CaC03)
182

200
190
204





410
385
389
MS
(mg/1 as
CaC03)
65

46
43
32





7
9
8
rlow-wei gh t ed avcrag es.
                  11 other values are arithmetic, means.
                                          576

-------
major pollution parameters.  The  iron
system generally produced the  lowest
residuals in terms of organics  and
phosphorus while the residual  suspended
solids in the effluents were essentially
equal.  The carbon systems  were run to
exhaustion; thus the organic concentrations
in the effluents are the averages of values
ranging from very low concentrations with
fresh carbon to essentially complete
breakthrough.

     Figure 2 illustrates the  decline  in
performance of the carbon systems with
cumulative applied loading.  It is apparent
that the removal of TOC by  the iron-carbon
adsorber declined at a  greater rate than
the  lime systems.  This is  to  be  expected
since the iron clarified-filtered waste-
water had a lower concentration of TOC
than the other streams.  According to
accepted adsorption models, organic removal
capacity of carbon decreases  as the
concentration of organics  in  the  wastewater
decreases.  The high lime  system  performed
somewhat better than the  low  lime system.
  100-
  12-
   80-
 o
 E
 £40-
   20-
                          HIGH LIME
                   IRON
                                  LOW LIME
0    5    10   15

 Cumulative Applied TOC, A,
                          20   25    30    35
                              g  TOC Applied
                               100 g  Carbon

 Figure 2.  Performance of activated carbon systems.
 O>
 E
O
O
   8-
                           SYSTEM
                                    FEED TOC
                         	IRON     9.5mg/l
                         	LOW LIME  12.5mg/l
                         	HIGH LIME  12.9mg/l
           Single Stage Carbon Dosage, Ds, mg/l
         200   100  75     50     40       30
          I
               I
                  75
                   I
                          I
          5     10    15    20    25    30    35

              Specific Throughput, q, l/gm


       Figure 3. Idealized breakthrough curve.
If, at a given  specific  throughput,  the
carbon in a single  adsorber  is  considered
exhausted, it would be removed  and replaced,
and the carbon  dosage at  that point  would
be calculated as the reciprocal  of the
throughput in appropriate units.  Figure  3
shows that for  any  given  effluent standard
the iron system will be  able to  treat more
sewage and the  carbon dosage will be less
than for the other  systems.

     A single carbon contactor  treating an
entire waste stream is the least efficient
contacting system from a  standpoint  of
carbon loading.  The entire  contents of the
single-stage contactor must  be  removed  and
replaced with virgin or  regenerated  carbon
when the effluent reaches the specified
limit.  Only a  fraction  of the  carbon in
the bed is completely saturated  while a
large portion of the bed  is  in  a state  of
partial exhaustion.  Other methods of
contacting are  commonly  used, such as
multiple-staged series operation, pulsed
bed operation and multiple single-stage
parallel operation.  Of  these,  only  the
multiple single-stage parallel  system can
be applied directly to the data  obtained  in
this project, since these adsorbers  were
strictly single stage.
     In Figure 3 the breakthrough of TOC
is shown as a function of specific
throughput or liters of sewage passed
through the adsorber per gram of carbon in
the adsorber.  Also shown on the abscissa
is the single-stage carbon dosage cor-
responding to the specific throughput.
     The carbon utilization  in  single-stage
contacting can be  improved by dividing the
total contactor volume  requirement into a
number of parallel  contactors.   By starting
the contactors in  staggered  sequence,  it
is possible to have on-stream at any given
time contactors in  various stages of ex-
haustion.  Thus, effluents from more
heavily loaded contactors  can be blended
                                            577

-------
        1.0-
 c
 o
 •*-
 o
 (0
 0 
  ro
 0) 
III i-
 o) 2
 0) O
 ro ro
 § «
 JD O)
 ro .E
 O W
        0.5--
                          —r
                           5
—r—
 10
—I—
 15
—i—
 20
                          Number of Parallel Single Stage Contactors

                        Figure 4. Effect of multiple contractors on carbon dosage.
with effluents  from  less heavily loaded
contactors to produce  the  desired effluent
quality.
     Figure 4 shows the savings  in  carbon
as the number of parallel contactors
increases.  For example, the carbon dosage
for an eight-contactor system with  stag-
gered start-up is 56% of the single
contactor dosage.
     To provide additional information  for
the performance comparison, cost  estimates
for treatment by carbon systems that
perform in accordance with the data ob-
tained in this study were made.   These
estimates include amortization of capital
as well as operation and maintenance  costs.
The assumptions used in the estimate  are
shown in Table 3.  The estimates  were made
for a 10 mgd  (38,000 cu m/day) carbon
adsorption system with eight parallel,
single-stage contactors at 34 min contact
time.  The relationship of carbon treatment
cost to carbon dosage was computed and  is
shown in Figure 5.  The treatment cost
increases with carbon dosage; nearly  all
of the increased cost results from
regeneration operation and maintenance
cost, including carbon makeup.
                                                   5-
   ~   3-
   a
   O
                                                                                        20
                                          15
                                          10
                         O
                         O
                         c
                         0)
                         E
                                             a
                                             O
           20   40   60   80  100  120
                 Carbon Dosage, mg/l
                                     140  160
     Figure 5. Relationship of carbon treatment cost
             to carbon dosage.
        Figure 6 shows the effect of the
   three pretreatment systems on the cost  of
   carbon treatment for varying effluent TOC
   levels.   Differences in carbon treatment
   cost  for the three systems studied  are
   significant at the low effluent TOC  levels,
   but  they diminish as the required level of
   treatment is reduced.  Over the entire
   range of effluent TOC considered in  this
                                            578

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      Table 3   Input Assumptions for
       Carbon System Cost Estimation
   Item
   Input Assumptions
 Avg.  daily flow

 Peak flow


 Amortization
   interest rate

 Amortization
   period

 STP CCI (EPA)*

 Wholesale price
   index*

 Hydraulic surface
   loading

 Carbon contact
   time

 No. of contactors

 Carbon cost

 Regeneration loss

 Power cost

 Fuel  cost

 Labor wage rate
10 mgd(38,000 cu m/day)

14.8 mgd (56,000 cu
                m/day)
6.0%


25 yr

2.025


1.535


4 gpm/sq ft(10 m/hr)


34 min

8

$0.42/lb ($0.93/kg)

8%

$0.020/kw hr

$0.10/therm($0.0006/MJ)

$5.50/hr
 "June,  1974.
study, the lowest feed TOC provided  by the
iron pretreatment system permits  the least
cost carbon treatment.  High-lime pre-
treatment results in  lower cost carbon
treatment than low-lime pretreatment with
the advantage diminishing greatly at
higher allowable effluent TOC  levels.

     These carbon treatment  cost  compari-
sons can thus be incorporated  into total
system cost comparisons to provide a
decision making mechanism for  selecting the
least total cost system.  Such additional
parameters as clarification  area  require-
ments, sludge dewatering requirements,
neutralization requirements, complexity of
operation and maintenance,  influent quality
characteristics,  and  effluent  quality
requirements should all  be  taken into
account in selecting  the chemical pre-
treatment system.  Figure 6 suggests that
differences in  carbon treatment  cost that
would result from utilizing the  various
chemical pretreatments studied here are
large enough at  low effluent TOC levels to
be considered in  making  the selection of
chemicals.  For example,  if the  effluent
TOC requirement were  5 mg/1, the low-lime
pretreatment system,  including clarifica-
tion, neutralization,  filtration,  and
sludge handling,  would have to cost at
least 3.4
-------
Removal of Heavy Metals by P-C Processes

Phase 1 (2)

     Concurrent with the previously
described study, heavy metals were added
to the influent of each pilot plant.
Samples of spiked raw sewage, clarifier
effluent, filter effluent, carbon effluent,
sludge and filter backwash were analyzed
for the specified metal.  The analytical
determinations were verified by mass
balance procedures.  Table 4 shows the
metal concentrations remaining in the final
effluents.  The concentration of metal
added to each system was 5 mg/1 except for
mercury, which was 0.5 mg/1.  For com-
parison, the U.S. EPA water quality
criteria for metals in potable water
sources are also shown.

        TABLE 4   RESIDUAL METALS
  CONCENTRATIONS FROM THREE SYSTEMS,  yg/1
       Quality    Iron   Low Lime  High Lime
Metal  Criteria  System   System    System
Mn
Ni
Zn
Cu
Cd
Ba
Pb
r III
Cr
r VI
Cr
As
Hg
50

5000
1000
10
1000
50
T 50

100
2
3820
37
192
155
50
271
30
6
21
58

235
38
561
169
44
25
29
16
87
915

37
12
584
352
14
942
19
18
76
770
54
     Mechanisms of removal include
precipitation as hydroxides, hydrous oxides,
carbonates and sulfates with subsequent
removal by sedimentation and filtration.
Activated carbon also removes certain metals
by adsorption.  These carbon columns were
anaerobic, thus providing a suitable
environment for the reduction of sulfate to
sulfide.  The concentration of sulfide was
widely variable but precipitation and
filtration of the heavy metals as the in-
soluble sulfide must certainly have
occurred in the carbon columns.

Phase 2 (3)

     After completion of the first phase of
the metals study and the chemical pre-
treatment study discussed previously, the
pilot plant underwent major revision.  The
flow scheme remained essentially the same,
but changes were made in the equipment.
The clarifiers were made deeper to allow
greater detention time.   The 4-in (10 cm)
carbon columns were replaced with two
5.75 in (14.6 cm) columns in series.  The
depth of carbon in each column was 8 ft
(2.4 m) for a total carbon depth of 16 ft
(4.9 m).  The hydraulic loading was
4 gal/min/sq ft (10 m/hr) resulting in
30-min contact time (based on empty bed
volume).

     During the second phase of the metals
study, the raw sewage was spiked with some
of the less common metals.  The clarifier
was operated using either iron (ferric
chloride, 40 mg Fe/1), lime (415 mg
Ca(OH)2/l, pH 11.5) or alum (220 mg/1).
The data are summarized in Tables 5, 6 and
7.  It can be seen that most of the metal
removal occurs in the chemical clarifica-
tion step.  However, carbon does remove a
significant fraction of some of the metals
applied.  For example, in improving the
removal of mercury from 94% to 98.3%
(Table 5), the carbon reduced the residual
concentration from 3.6 ppb to 1 ppb, 56%
removal across the carbon.  Table 6 shows
that where lime was not particularly
effective for mercury, antimony, selenium,
thallium, and vanadium, carbon increased
the total removal significantly.

     This project has now produced a large
body of data relating to the fate of many
heavy metals in independent physical-
chemical treatment processes.  The com-
bination of chemical clarification,
filtration and activated carbon adsorption
is effective for the removal of most heavy
metals, assuming the proper choice of
chemical.  Molybdenum, for example, was not
removed by alum or lime, but the ferric
chloride-carbon process gave 80% removal.
The metal residual after clarification and
filtration should be somewhat predictable
                                           580

-------
                      TABLE 5
METALS DATA SUMMARY, ALUM COAGULATION
Initial
Metal Oxidation Concentration
State PPM
Cumulative % Removal
PPB Residual
Metal
Clarifier Filter Carbon Carbon





















Silver +1
Beryllium +2
Bismuth +2
Cobalt +2
Mercury +2
Molybdenum +6
Antimony +3
Selenium +4
Tin +2
Titanium +4
Thallium +1
Vanadium +5
Manganese +2
Nickel +2
Zinc +2
Copper +2
Cadmium +2
Barium +2
Lead +2
Chromium +3
Chromium +6
0.6
0.1
0.6
0.8
0.06
0.6
0.6
0.5
0.6
0.6
0.6
0.5
0.7
0.9
2.5
0.7
0.7
0.5
0.6
0.7
0.7
based on solubility products and jar tests.
Carbon provides additional removal of most
metals, the extent of which can best be
determined by pilot column operation.
Effects of pH on Removal of Organics from
Wastewater
by Activated Carbon

95
93
92
47
88
4
61
53
92
95.3
33
86
31
25
1
70
43
87
91
93
61
96.9 99
98.1 98
95.5 96
49 56
94 98
0 10
62 71
48 56
95 . 3 94
>95.8 >95
31 39
94 >99
30 33
25 37
1 28
67 98
45 55
79 92
95.5 96
97.6 99
64 97
.2 5
.9 1
.9 19
352
.3 1
540
174
220
36
.8 <25
366
.5 <3
469
569
1800
.3 12
.5 312
40
.6 20
.3 5
.4 18
were different for different conv
The manipulation of pH is not un
physical-chemical systems, occur
lime clarification and neutraliz
also incidentally when using the
salts, ferric chloride or alum.
justment of pH is a relatively e
     Early research on activated carbon
treatment of secondary effluent seemed to
indicate that adsorption of refractory
organics improved with decreasing pH.
Later work, however, showed that pH effects
                operation.  Thus, a P-C carbon system
                could easily be operated at any reasonable
                pH if adsorption were improved.

                     One of the Cincinnati P-C pilot plants
                was outfitted to provide data on the
                                            581

-------
TABLE  6--METALS DATA SUMMARY, IRON COAGULATION
Metal
Silver
Beryllium
Bismuth
Cobalt
Mercury
Molybdenum
Antimony
Selenium
Selenium
Tin
Titanium
Thallium
Vanadium

Metal
Silver
Beryllium
Bismuth
Cobalt
Mercury
Molybdenum
Antimony
Selenium
Selenium
Tin
Titanium
Thai I ium
Vanadium
Oxidation
State
+1
+2
+ 2
+ 2
+ 2
+ 6
+ 3
+4
+ 4
+ 2
+ 4
+ 1
+ 5
TABLE 7--
Oxidation
State
+ 1
+ 2
+ 2
+ 2
+ 2
+ 6
+ 3
+4
+4
+ 2
+ 4
+ 1
+ 5
Initial PFB Residual
Concentration Cumulative °o Removal Metal
PPM
Clarifier Filter Carbon Carbon
0 . 5 94
0.1 93
0.5 83
0.5 27
0.05 92
0.6 66
0.5 60
0.1 66
0.05 68
0.5 95
0.5 84
0.6 36
0.5 93
METALS DATA SUMMARY, LIMP, C
98.2
94
94
18
98
6S
65
75
80
98.0
87
30
97.2
99.1
98.9
96.2
30
99
80
72
80
75
98 . 5
90
45
97.8
5
1
19
350
<1
120
140
20
13
8
50
330
11
0 Anil I, AT I ON
Initial
Concentration Cumulative "« Remov
PPM
Clarifier Kilter C
0.5 95.8
0.1 97.8
0.6 90
0.5 90
0 . 5 4 5
0.5 NO RP.MOVAI
0.6 21
0.5 36
0 . 06 4 6
0 .5 91
0.5 92
0.5 54
0.5 55
97.1
99.4
95.3
91
70
•
28
35
38
92
95 . 5
60
57
al
a rbon
98
99.5
96
95
91

52
95
67
92
95 . 3
72
91
PPB Residual
Metal
Carbon
.10
1
24
25
45

288
25
20
40
24
140
45
                       582

-------
influence of pH on carbon performance.  Raw
sewage was clarified with 194 mg alum/1.
The dosage was manually adjusted to main-
tain pH 6.4 ± 0.2.  After dual-media
filtration at 3.9 gal/min/sq ft (9.5 m/hr),
the effluent was split into three streams.
The pH's of two of the streams were ad-
justed to 4.0 and 8.8, respectively, and
pumped to separate carbon adsorbers.  The
third stream was pumped at ambient pH (6.4)
to a third adsorber.  These were identical
adsorbers treating the same wastewater at
three different pH's.  The adsorbers were
5.75 in (14.6 cm) two-stage series with
8 ft (2.4 m) of Filtrasorb 300 carbon per
stage for a total carbon depth of 16 ft
(4.9 m).   The hydraulic loading was 6 gal/
min/sq ft (15 m/hr) resulting in 20 min
total empty bed contact time.  Sodium
hydroxide and sulfuric acid were injected
by pH controlled metering pumps into the
carbon column feed streams upstream of
in-line mixers.  There was no difficulty
maintaining constant pH.
     Table 8 shows the results of the alum
clarification-filtration treatment of raw
sewage over the six months study.   Alum
clarification-filtration was highly
effective for removal of total organic
carbon (TOG), suspended solids (SS),
phosphorus (P) and turbidity.  Around 40%
removal of soluble TOC (STOC), color and
total Kjeldahl nitrogen was observed.
                     Operation of the  carbon  columns  at
                pH 4.0, 6.4 and 8.8 did produce varying
                results.  Figure 7 shows breakthrough of
                TOC with throughput.   The  low pH  system
                performed poorly from  the  start,  and  was
                exhausted rather quickly.  The high pH
                system provided the best effluent through
                most of the study.  There  was an  apparent
                alteration of the wastewater  caused by
                elevating the pH to 8.8.   This was
                evidenced by much higher solids con-
                centration in the carbon column backwash
                water than from the others.   This led  to
                the suspicion that precipitation and
                filtration of soluble  or colloidal organics
                was providing improved removal.   However,
                analysis of data on the ratio of particu-
                late TOC to total TOC  showed no significant
                difference at the three pH's.  The per-
                formance of the column which received pH
                6.4 wastewater was poorer than the high
                pH column at the beginning, but declined at
                a slower rate, indicating the development
                of some biological activity as the study
                progressed.   The pH 6.4 column was the only
                one which discharged any sulfide  (0.5 mg/1),
                indicating a more suitable environment for
                biota than the other two.   Biological
                activity was probably not a major factor
                because of the low feed organics  (15 mg
                TOC/1)  and the fact that the beds were kept
                very clean by daily air-scour, water
                backwash.
           TABLE 8  - POLLUTANT REMOVAL BY ALUM CLARIFICATION AND FILTRATION
           Parameter
Raw Sewage
After Clarification
  and Filtration
                                                                    %  Removal
TOC, mg/1
STOC, mg/1
SS, mg/1
Color, units
P, mg/1
Alk. , mg CaC03/l
Turbidity, units
NH3, mg N/l
TKN, mg/1
96.1
23.6
235
42
7.3
186
84
11.2
21.3
15.1
13.5
7.8
25.4
0.3
101
5.2
11.1
12.6
84
43
97
40
96
-
94
-
41
                                           583

-------
   1.0
   0.8
 O)
 c
   0.6
O
O
   0.4
 2 0.2
     _ BREAKTHROUGH OF TOC
                               pH 6.4
           2     4      6      8      10     12
            Volume Treated (1000 Bed Volumes)


           Figure 7. Breakthrough of TOC.
     After the six-months study was com-
pleted samples of carbon from the first
eight feet of each system were subjected to
thermogravimetric analysis.  Weight loss
at 475°C in a nitrogen atmosphere was
measured.  The pH 6.4 and 4.0 system spent
carbon samples showed approximately equal
weight loss, while the weight loss of the
pH 8.8 spent carbon sample was about 50%
higher.  While this measurement may not
correlate quantitatively with organics
adsorbed on the spent carbon, it does
indicate that the higher pH was favorable
for adsorption of the organic materials in
the wastewater studied.  It also indicates
little difference in adsorption at pH 4.0
and 6.4, implying that the obvious improve-
ment in removal at pH 6.4 over pH 4.0 might
be the result of biological activity.  This
weight loss analysis is very limited data,
and the implications suggested here are
only speculative.

     Figure 8 illustrates the results of a
data analysis similar to that outlined
earlier for the study on effects of chemical
pretreatment.   Cost analysis assumptions
are the same as those used earlier and as
shown in Table 3.  This shows total carbon
treatment cost as a function of effluent
TOC.  At low effluent TOC requirements,
operation at the higher pH is the obvious
choice.  At less stringent effluent
standards (<50% removal across the carbon),
there is little to choose between the pH
6.4 and 8.8 operation.  Operation of a
           COST OF CARBON TREATMENT

                              (June,1974)
        4    5   6   7   8   9   10
         Eight Contactor Blended Effluent TOC, mg/l


        Figure 8.  Cost of carbon treatment.
carbon column at low pH  is not  indicated
for this wastewater.

Formation and Removal of Chloro-organics
in a Tertiary Breakpoint Chlorination-
Activated Carbon System

     At the request of EPA Region  III,  EPA
Cincinnati is1 undertaking an  extensive
pilot study of the formation  of chlorinated
organics during the process of  ammonia
removal by breakpoint chlorination (BPC).
Region III has awarded a construction grant
to the Washington Suburban Sanitary  Com-
mission (WSSC) for the construction  of  a
60 mgd (230,000 cu m/day) advanced waste
treatment plant in Montgomery County,
Maryland.   Region III is in the process of
preparing an Environmental Impact  Statement
for the Montgomery County facility.  The
question of the extent of formation  and
removal of chlorinated organics during  the
breakpoint process was encountered because
of recent innovations in analytical
chemistry which disclosed the presence  of
these possible carcinogens in many
municipal water supplies.  Since the
Montgomery County plant  effluent will dis-
charge to the Potomac upstream  of  the
drinking water intake of Washington, D.C.,
Region III asked MERL to supply data to
indicate the extent of the chloro-organics
problem likely to be encountered.

     A brief preliminary study  was con-
ducted wherein batches of lime  clarified
and filtered secondary effluent were pump-
ed through a BPC system  followed by  a  short
contact time  (2-1/2 min) carbon column.
This was done to provide quick  data  to  the
Region, recognizing the  limitations  of  poor
                                           584

-------
chlorination control and unrealistic
operating parameters.  During eight days of
operation BPC and short contact carbon
treatment produced the results shown in
Table 9.   Only chloroform was detected
above 1 yg/1 in the lime clarified and
filtered activated sludge effluent.  Only
small quantities of the haloforms were
found after breakpoint with the exception
of chloroform and bromodichloromethane.
The concentrations for these two compounds
are in the same range as values observed
by others in the City of Cincinnati tap
water  (45 yg chloroform/1 and  13 yg
bromodichloromethane/1).  The  TOC  of the
lime clarified-filtered secondary  effluent
was  10 mg/1.

     During the eight days  of  this study-,
the  carbon was effective in removing the
small  amounts of halomethanes  formed by
chlorination, with the  exception of
chloroform.  Figure  9 shows the formation
and  removal of chloroform.  Breakthrough
from the  carbon column  began on about  the
second day  and continued to complete
breakthrough on the  last day of the run.
The  chloroform loading  at complete break-
through was 73 yg CHClj/g carbon.

     While  the preliminary  study discussed
above  was being carried out, the P-C pilot
plant  formerly used  for the study  on effects
of pH  was being revised for an extensive
  100
   80
   60
 oi
 =L
 _
 O
 O
   40
   20
    01    234    56    7    8
                    Days

    Figure 9.  Formation and removal of chloroform.


study of the BPC-carbon system.  Trickling
filter effluent will be supplied as pilot
plant feed.  Lime feeding and  acid neutrali-
zation controlled by automatic pH equipment
was installed.  Again, three parallel
          TABLE 9   FORMATION AND  REMOVAL  OF  VOLATILE  CHLORINATED ORGANICS
Feed
CHC13
C H Cl ^
242
BrCHCl2
Br2CHCl
CHBr3
1-12
ND

ND
ND
ND -
(4
0.

<0
<0
<0
avg.)
7

.1
.1
.1
B.P.
11-96
ND 2

<0.1
ND 0
ND 0
Cl? Eff.
(40 avg.)
.5

22
.3
.8
Carbon Eff.
0.1
ND

ND
ND
ND
— >
- 0.

- 0.
- <0
- <0
breakthrough
2

3
.1
.1
          (a)  Single  peak for C-H.Cl- and CC1. - expressed

          (b)  ND  -  no peak observed

          (c)  <0.1    detectable but too small to quantify

          (d)  All values yg/1

          (e)  Three grab samples per day

                                            585

-------
carbon systems will be used to treat filter
effluent.  One will incorporate a BPC
system between the filter and the first
stage of carbon.  The second will have a
BPC system installed between the first and
second stages of the carbon system.  The
third carbon adsorber will not have a BPC
system.

     The ammonia content of the influent to
each BPC system will be monitored by a
Technicon Auto Analyzer.  The ammonia
concentration will be transmitted as an
electrical signal to a sodium hypochlorite
feed pump controller.  This will cause the
feed pump to add chlorine at a predetermined
ratio to achieve breakpoint.  Success of
ammonia oxidation will be monitored by
analyzing effluent streams after carbon
treatment.  Free and total chlorine will
also be measured by the Auto Analyzer at
various points in the system.  The pH of
the chlorination reactions will be
controlled automatically.  The carbon
systems will be operated upflow with
8 ft (2.4 m) of Filtrasorb 400 per stage
for a total depth (at repose) of 16 ft
(4.9 m).  The hydraulic loading will be
6 gal/min/sq ft (15 m/h) for a total
contact time of 20 min  (based on empty bed
volume, carbon at repose).

     As soon as the major process equipment
revisions could be completed, one BPC
system was operated for a period of three
weeks with manual control of the chlorine
feed rate.  The BPC system that preceded
carbon treatment was the one chosen for
this run.  The operator would take the
ammonia reading from the on-line Auto
Analyzer and manually set the hypochlorite
feed pump to deliver the appropriate
chlorine dose.  Free and total chlorine
were measured amperometrically and the
carbon effluent ammonia content was
monitored by the in-line Auto Analyzer.

     The data from the three-week run have,
as of this writing, not yet been completely
analyzed.  However, certain preliminary
observations can be made.  The halo-
methanes were formed at concentrations
somewhat higher than observed earlier.  The
feed to the BPC system varied considerably.
from 5 yg/1 to 250 yg/1.  Figure 10 shows
the chloroform concentration in the influent
to the carbon system  (after BPC), the
effluent from the first stage carbon and
the effluent from the second stage carbon
column.  Breakthrough of chloroform through
   250 r
   200 -
    150 -
  O)
  a.
  _
  o
  i
  o
   100 -
    50 -
   N.D.
    •tage Effluent


Final Effluent
 Figure 10.  Chloroform removal by activated carbon.

the first 8 ft  (2.4m) of  carbon began very
quickly.  However, the final effluent never
exceeded 10 yg/1.  This could  indicate that
contact times longer than  10 min are re-
quired for efficient chloroform removal.
This question will be addressed in more
detail in future work.

     The data showing that effluent from
the first stage carbon at  times was higher
than the influent implies  that the adsorp-
tion of chloroform is easily reversible.
This will also be investigated further.

     When all the automatic control
equipment is installed, the three carbon
systems will go on-stream  continuously in
order to provide data on not only the
formation and removal of halomethanes, but
also on the oxidation of ammonia with
chlorine, the effect of chlorine on carbon
life, and control and operational problems
involved with the BPC system.  Questions
on the halomethane problem that will be
answered include:

     1.  Correlation between chlorine dose
or residual and halomethane production.
                                           586

-------
     2.   Effect of precursor removal on
halomethane production (BPC after first
stage carbon).

     3.   Capacity of carbon to remove
halomethanes.

     4.   Influence of carbon contact time
on removal of halomethanes.

Enhancement of Granular Activated Carbon
Performance by the Addition of Nitrate

     Under contract with EPA, the Los
Angeles  County Sanitation District con-
structed and operated a 50 gal/min (3.2
                    I/sec) P-C pilot plant at Pomona,
                    California (4).   The system consisted of
                    chemical clarification of raw sewage using
                    alum and polymer followed by treatment in a
                    downflow carbon column.  Performance and
                    system parameters are shown in Table 10.
                    The major objective of the project was to
                    learn what problems could result from long
                    term treatment of chemically clarified raw
                    sewage.  It was realized that biological
                    growths in the P-C carbon systems might
                    cause severe problems of plugging and/or
                    sulfide generation.  Thus, the Pomona
                    project was designed to quantify these
                    effects and to investigate measures to
                    alleviate the problem conditions, should
                         TABLE 10 - POMONA P-C-T PILOT PLANT
         Parameter

         TCOD, mg/1
         DCOD, mg/1
         SS, mg/1
         Turb., JTU
         BOD5, mg/1
         Color units
         P, mg/1
         N03, mg N/l
         PH

         Clarifier
Raw Sewage

   321
   49
   199
   11.1
    7.7
Clarifier Eff1.

     96
     49
     28
     23
     36
     20
     1.3
     0.9
     6.8
Carbon Eff1,

    19
    14
    7
    6
    0.9
    1.3
    6.8
              Flow   60 gal/min (3.8 I/sec) constant
              Overflow Rate - 1180 gal/day/sq ft (48 cu m/day/sq m)
              Weir Loading - 10 gal/min/ft (2 1/sec/m)
              Detention Time   84 min
              Alum Dose   25 mg Al/1
              Polymer Dose - 0.3 mg/1 - anionic
              Sludge Production - 2000 Ib/mil gal (250 mg/1)

         Granular Carbon

              Flow   50 gal/min (3.2 I/sec) constant
              Hydraulic Loading   4 gal/min/sq ft  (10 cu m/hr/sq m)
              Contactor Type - Single Stage Packed Bed Downflow
              Carbon Size   8x30 mesh
              Carbon Depth   16 ft (4.9 m)
              Empty Bed Contact Time   30 min
              Sodium Nitrate Dose   33 mg NaNOj/l
              1st Cycle Carbon Loading - 3.5  g TCOD  removed/g carbon  (1.5 g DCOD/g)
              1st Cycle Carbon Utilization rate  < 173 Ib/mil gal (21  mg/1)

         Note:   Carbon column ran 18 months (1st cycle) prior to regeneration
                and was not  exhausted.   Three regeneration runs were  conducted
                in order to  obtain regeneration data.   Performance data shown
                above is average data over entire 27-month operation.
                                          587

-------
they appear.  Of course, process per-
formance would also be monitored.  Another
important objective was to obtain data
on the regeneration of P-C carbon,  which
would likely be heavily loaded with or-
ganics and possibly carry biological slimes.

     As expected, hydrogen sulfide  appeared
in the carbon effluent after several weeks
on stream.  Table 11 shows the measures
used in attempting to eliminate the sulfide,
including backwash methods,  aeration or
chlorination of carbon influent and nitrate
addition.  The final solution was the ad-
dition of 33 mg NaNOj/l.  Nitrate is
reduced to nitrogen gas and the resulting
oxygen is used as hydrogen acceptor in the
biochemical utilization of substrate.
Nitrate addition caused additional pressure
drop, but it was within the design pressure
capacity of the system.  The increase in
headless during a 24-hour run between
backwashes was always less than 50 psi
(340 k N/sq m) and on the average less
than 30 psi (210 k N/sq m).   A welcome
result of the nitrate addition at Pomona
                TABLE 11   PERFORMANCE OF THE VARIOUS H2S CONTROL
                                        AT POMONA
H S Control Methods
2
(1) Surface wash Backwashing
Technique
(2) No. (1) Plus intermittent
02 addition to carbon
column at D.O. level
= 4 mg/1
(3) Surface wash + Air/water
backwash plus oxygenation
of the chemically clari-
fied effluent to D.O. 2-6
mg/1
(4) No. (3) + 20 mj,/l Cl2a
added to carbon influent
(S) No. (3) + 40 mg/1 C12
added to carbon influent
(6) No. (3) + 2.9 mg/1 N b
added to carbon influent
(7) No. (3) + 4.5 mg/1 N
(8) No. (3) + 5.1 mg/1 N
(9) No. (1) + 5.3 mg/1 N
10) No. (1) + 5.4 mg/1 N
Carbon Effluent Total Sulfide,
Cone. , mg/1 S
Average

2.86



1.85




1.87

1.74

1.13

0.3
0.13
0.05
0.019
0
Range

1.0 5.7



1.4 2.5




0.8 3.0

0 4.3

.09- 2.6

0 .95
0 0.60
0 .26
0 .10
0 .05
            a  added as sodium hypochlorite solution
            b  added as sodium nitrate solution
                                           588

-------
and one not entirely expected was an
apparent indefinite extension of the life
(capacity) of the carbon.  The carbon
column was operated for 18 months with-
out replacement and without a significant
decline in organic removal efficiency.
The apparent carbon loading during that
time reached a phenomenal 3.5 g COD re-
moved/g carbon of which 1.54 g/g was
soluble COD.  Considering that values in
the range of 0.5 g COD removed/g carbon
are commonly accepted for carbon loading
in physical-chemical systems, it is
apparent that the mechanisms of filtration
(particulate COD "loading" was 3.5-1.5
= 2 g/g) and nitrate assisted biological
activity contributed greatly to the
organics removal.

     In order that the Pomona experience
could be verified and expanded at another
location, the Lebanon pilot plant facility
is currently modifying an existing P-C
pilot system to run an upflow carbon column
on lime clarified-neutralized raw waste-
water.  Sodium nitrate will be added prior
to the carbon column, and the performance
will be monitored for a long period of
time.  It may be possible that nitrate
oxygen will enhance the biological activ-
ity within a carbon column such that the
replacement rate of the carbon is signifi-
cantly reduced or even eliminated.

     FULL SCALE TREATMENT OF MUNICIPAL
      WASTEWATERS BY ACTIVATED CARBON

     There are several tertiary activated
carbon systems now in operation producing
effluents of reuse quality.   South Tahoe
effluent is pumped to a reservoir which
is used for sport fishing and as an irri-
gation water supply.   Colorado Springs
carbon effluent is used as power plant
cooling water.   Orange County Water Dis-
trict, with a system similar to Tahoe's,
will inject the carbon effluent, after
blending with low TDS water, into the
underground aquifer to prevent salt water
intrusion.   The use of reclaimed wastewater
(including carbon treatment) for augmenta-
tion of drinking water supplies is being
seriously considered in certain water-
short areas of this country.  Direct pot-
able reuse has been routinely practiced at
Windhoek, South Africa.

     The first full-scale facility in the
United States which treats a waste of pri-
marily domestic origin by only P-C proc-
esses is now on  stream  at  Rocky  River,
Ohio.  This 10 mgd  (38,000 cu  m/day)
facility utilizes alum  and polymer  to
clarify raw sewage  in existing primary
clarifiers which have been equipped with
internal flocculation mechanisms.   Clari-
fier effluent is then pumped through a
bank of eight parallel  carbon  adsorbers.
The carbon effluent  is  then discharged  to
Lake Erie.  The  Research and Development
Program of EPA and  its  predecessor  organi-
zations has helped  to finance  the con-
struction of the activated carbon facility
via an R&D grant.   Following the shakedown
and upon initiation  of  full flow through
the carbon system,  a one-year  evaluation
period will begin.   Complete records of
operating conditions and performance will
provide essential information  on the
effectiveness of the P-C system at  full
scale.  Extensive cost  and time accounting
will allow determination of the actual  cost
of the system and all subsystems.   The  man-
hour requirements for operational duties,
preventative maintenance and unscheduled
maintenance will be  catalogued so that  the
data will be relevant not  only to this
combination of processes but to any other
system containing one or more  of the proc-
esses used at Rocky  River.

     After the one-year evaluation period
the performance, operating  and cost data
will be compiled in a technical report.
At that time, the U.S.   consulting engineers
and wastewater treatment agencies will have
access to the experience and data gathered
at the first full-scale P-C facility.   This
will be a major addition to the body of
knowledge in the municipal  wastewater treat-
ment field.

               SUMMARY

     The removal of organic materials from
municipal wastewater by activated carbon
has been practiced for  several years in the
tertiary systems, and now  is being demon-
strated in a P-C system.  Much knowledge
has been gained over the last decade,  and
carbon system design is no  longer a mystery,
However, there is still much to learn about
the mechanisms of removal  of exotic and
commonplace organic compounds by this
versatile adsorbent.  The  factors affecting
adsorption of specific  compounds or classes
of compounds have not been  fully defined
nor have methods of prediction of adsorp-
tion performance.
                                           589

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     As technology develops and more and
varied organic materials enter and are
detected in the water environment, acti-
vated carbon can be expected to assume
an expanding role in environmental pro-
tection.

References

1.  Westrick, J.J., and Cohen, J.M.,
    "Comparative Effects of Chemical
    Pretreatment on Carbon Adsorption."
    Presented at the WPCF 45th Annual
    Conference, Atlanta, Georgia,
    (Oct. 1972).  In Press.

2.  Maruyama, T., Hannah, S.A., and
    Cohen, J.M., "Metal Removal by
    Physical and Chemical Treatment
    Processes," Jour WPCF, 47, 962
    (May 1975).

3.  Hannah, S. A., Jelus, M.,  and Cohen,
    J.M., "Removal of Uncommon Trace
    Metals by Physical and Chemical
    Treatment Processes."  Presented at
    the 48th Annual  Conference,  WPCF,
    Miami Beach, Florida (Oct. 1975).

4.  Directo, L.S., Chen, C.L., and
    Kugelman, I.J., "Pilot Plant  Study
    of Physical-Chemical Treatment."
    Presented at the 47th Annual  Con-
    ference, WPCF, Denver, Colorado,
    (Oct. 1974).
                                           590

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                                 NEW  INDUSTRIAL  WASTEWATER

                           SEPARATION PROCESSES  DEVELOPED  UNDER THE

                                   EPA  RESEARCH PROGRAM

                                        J.  Ciancia
                  Industrial Environmental Research  Laboratory-Cincinnati
                                 Edison, New Jersey   08817



                                         ABSTRACT

     This paper describes  the  Industrial Research and Development Program  of  the U.  S.
 Environmental Protection Agency  followed by a brief discussion of an  approach companies
 should use for abating pollution at  manufacturing plants.  Separation technologies  in-
 volving chemical  recovery  and/or wastewater reuse that  have been developed under the
 Industrial R§D Program of  EPA  are then  discussed.   The  technology developments  covered
 are  (1) a novel ion exchange technique  for  separating acids from metals to permit the re-
 use  of spent processing baths, (2) an ion exchange  process for recovering  chromate  from
 pigment manufacturing wastewaters, (3)  the  development  and in-plant demonstration of
 reverse osmosis and electrodialysis  for recovering  chemicals and reusing water  from  rinse
 waste discharges  in the metal  finishing and fabricating industries, (4) a  novel approach
 for  increasing the heat and mass transfer while  also preventing scaling in vertical  tube
 evaporators and its demonstration on a  pilot plant  scale  for several  inorganic  wastewaters,
 and  (5) a closed-loop type treatment approach involving electrolytic  copper recovery, pro-
 cess changes and  integrated chemical treatment  of rinse waters  that have been applied on
 a  full scale for  abating pollution at a copper  and  brass  wire mill.
               INTRODUCTION

     The significance and complexity of the
 industrial pollution problem coupled with
 recent governmental legislation has spur-
 red the development of new and improved
 technology for treating and/or recovering
 the multitude of wastes that spew from the
 Nation's industrial plants.

     With the passage of the Clean Water
 Restoration Act of 1966, the U. S. Environ-
 mental Protection Agency assumed a key
 role in the development of more effective
 and economical technology for treating
 industrial wastes.  Under the provisions
 of this Act,  EPA initiated a program to
 develop and demonstrate new and improved
 technology for the prevention, control,
 treatment, recovery and reuse of industri-
 al wastes.  The Agency's authority to de-
velop improved industrial and joint indus-
trial/municipal wastewater treatment
systems was expanded with the passage of
the Federal Water Pollution Control Act of
1972.  Moreover, this legislation estab-
lishes closed-loop type technology as the
direction to pursue in developing new pol-
lution abatement approaches by declaring
that it is the national goal to eliminate
the discharge of pollutants into the nav-
igable waters of the United States by 1985.
As a result, the EPA Research, Development
and Demonstration Program has become more
strongly oriented toward technology that
can accomplish chemical recovery and water
reuse at the same facility or through by-
product recovery of the waste materials.

     The Industrial Research and Develop-
ment Program in EPA is carried out by in-
house efforts, grants and contracts.  How-
ever, the bulk of the studies to date have
                                          591

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been carried out through the grant and con-
tract mechanism, which permits the program
to utilize the best science and engineering
talent in the Nation's universities, private
research institutions, and industry.

     The objectives of the program are to
assess the pollution problems and current
abatement practices in relation to the needs
of the industries, and support research,
development and demonstration studies in-
volving technology with a high potential for
solving the most significant problems at the
least cost and with a maximum amount of
chemical recovery and water reuse.  To war-
rant support, it is necessary that prelim-
inary investigations show that the proposed
technology is technically feasible and more
attractive than existing commercial ap-
proaches for abating specific waste prob-
lems.  Studies are supported at all stages
of development from the bench scale through
pilot plant and full scale demonstrations.

  ABATEMENT OF INDUSTRIAL WASTE PROBLEMS

     In approaching pollution control, each
plant must first define the problem by iden-
tifying all waste sources, including the
characteristics, volumes and pollutant loads
associated with each discharge.  With the
problem defined, process change and in-plant
control techniques can now be considered
and implemented where feasible for conserv-
ing water and eliminating all unnecessary
wastes.

     Since it is much simpler to recover
components before waste streams are combined,
and thus become complex mixtures of contam-
inants, the next step in a pollution control
program is to carefully assess the different
waste sources to explore the application of
closed-loop type technology.   Where chem-
ical recovery and water reuse do not appear
to be feasible, the application of alterna-
tive treatment technology should then be
considered for the remaining waste streams
on an individual and/or combined basis to
meet governmental effluent requirements
with a minimum of capital, operating and
overall environmental costs.

         NEW ABATEMENT TECHNOLOGY

     The purpose of the remainder of this
paper is to provide some insight into closed-
loop type developments associated with EPA's
Industrial R&D Program and the application
of these approaches  to  industrial  pollution
problems for achieving  chemical  recovery
and/or water reuse.

Ion Exchange

     Unlike the widespread  application
achieved in water treatment,  the commercial
use of ion exchange  for processing and  waste
treatment has been rather limited.   However,
there has been considerable interest in the
use of ion exchange  as  a pollution control
tool in the last several years.  This stems
from a combination of factors, including
the intensified interest in pollution con-
trol, the capability of the technique to
recover chemicals and purify wastewater, and
the availability of  improved ion exchange
resins.

     Recently, a novel  ion  exchange  tech-
nique for separating strong acids  from  metal
contaminants was shown  to be economically
feasible for reclaiming phosphoric acid used
in the bright finishing of  aluminum.  Refer-
red to as "acid retardation," the  technique
permits the separation  of strong acids  from
their salts by passage  of the solution
through the corresponding salt form  of  a
strong base ion exchange resin.  While  the
mechanism of the process is  not  completely
understood, acid retardation  separations
involve the preferential absorption  of  strong
acids on the resin which "retards" or slows
down the movement of these  acids through
the bed relative to the salt.  The acid
molecule is desorbed from the resin  by
water, thus eliminating the  need for chem-
icals to regenerate the ion  exchanger as in
conventional ion exchange treatment  processes.

     The acid retardation process  has been
optimized in pilot plant equipment using
actual phosphoric acid wastewater  from
aluminum bright finishing production opera-
tions.  The study utilized  a continuous
countercurrent contactor to  obtain maximum
efficiency in separating the phosphoric
acid from aluminum.

     The pilot plant study  showed that over
75% of the acid content could be recovered
from feed streams containing 25-35%  phos-
phoric acid which is generally obtained in
the countercurrent rinsing  of aluminum  parts
after bright finishing.  In this application,
the ion exchange resin  accomplishes  the
separation by absorbing the  phosphoric  acid
while the aluminum remains  in the  wastewaters
                                           592

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and passes out the column in the effluent.
The acid is eluted from the bed with water,
concentrated by evaporation, and returned
to the bright finishing processing operation.

     The economic evaluation of the process
based on the pilot plant results indicates
that the required capital investment could
be recovered in about 1.5 years when both
the cost of the recovered acid and alterna-
tive chemical waste treatment are considered.
For those plants where the 35% waste acid
can be returned to the supplier, the addi-
tional savings afforded by the "acid retar-
dation" system is estimated to return the
investment in approximately two years.

     In another development, a new ion ex-
change approach has evolved for recovering
chromate and zinc from wastewaters discharged
from the manufacture of zinc yellow pigment.
A full scale in-plant demonstration showed
that the new waste abatement system is high-
ly effective and much more economical than
chemical treatment.  In general, the tech-
nology for treating wastewaters from the
inorganic pigment industry is presently
limited to pH control, precipitation, and
removal of suspended solids by conventional
liquid/solid separation techniques.

     The new approach involves passing the
mother liquor and wash waters through a
strongly basic anion exchange resin, which
reduced the chromate content of the waste-
water from 2,700 ppm to about 1-2 ppm in the
in-plant demonstration.  The effluent from
the ion exchange column is neutralized with
sodium carbonate to precipitate the zinc.
The insoluble zinc carbonate is removed by
filtration and then dried for sale.  Regen-
eration of the ion exchange column is
accomplished with a heated alkaline salt to
remove the chromate which is reused in the
manufacturing operation.

     When considering the costs associated
with conventional chemical treatment (includ-
ing sludge disposal) and the savings from
the recovered chromate and zinc, the compa-
ny estimated that only 2-3 years would be
required to amortize the capital expenditure
of $125,000 for the ion exchange system.
It was also concluded from the study that
the new ion exchange approach has potential
for economically treating other chromate
pigment manufacturing wastewaters.
Membrane Technology

     The U.S. Environmental Protection Agency
has an extensive extramural program underway
to develop and demonstrate new membrane tech-
nology for abating pollution from metal fin-
ishing and nonferrous metal fabricating
plants.  Techniques such as reverse osmosis
and electrodialysis are attractive approaches
for treating rinse wastes.  When used on
individual rinse waters, this type of tech-
nology can accomplish simultaneous concen-
tration of the chemicals for return to the
processing bath while purifying the waste-
water for reuse in the rinsing operation.

     The reverse osmosis studies may be grouped
into three categories.  The first, which has
been completed, involved testing all com-
mercially available membranes and configu-
rations on the various major types of rinse
waters.  In another phase of the program,
new membranes with improved properties are
being tested, especially those which have
the potential for expanding the application
of RO to higher and lower pH conditions as
well as oxidizing contaminants.  The remain-
der of the program involves carrying out
full scale demonstrations under actual plant
conditions where attractive applications have
been identified in order to firmly establish
the economic feasibility of the approach for
the particular rinse waste.

     At the present time, cellulose acetate
in several configurations and hollow fiber
polyamide are the only reverse osmosis mem-
branes that are commercially available for
use in the treatment of industrial waste-
waters .  In the pilot plant study, extensive
tests were carried out on the use of cel-
lulose acetate tubular and spiral wound and
hollow fiber polyamide membranes for treating
the major metal finishing rinse waters.  Re-
verse osmosis was found to be generally
applicable except for oxidizing conditions
such as are encountered with chromic acid,
and high and low pH rinse waters.  The study
showed that the hollow fiber polyamide mem-
brane is suitable over a pH range of 4 to
11 and that the cellulose acetate spiral
wound and tubular membranes have reasonably
good operating lives from pH 2.5 to 7.

     Based on the pilot plant investigation
and subsequent demonstrations under actual
plant conditions, reverse osmosis has been
shown to be a feasible treatment/recovery
technique for metal finishing rinse waste-
waters.  However - the field demonstrations
                                           593

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 also underscore the need for some prelim-
 inary investigation prior to deciding on the
 use of reverse osmosis because of the com-
 plex nature of the processing baths which
 generally contain proprietary additives.

      The field demonstrations were carried
 out on copper cyanide rinse wastes at two
 plants and nickel plating rinse waste at one
 location using a hollow fiber polyamide mem-
 brane system.  Although no problems were
 encountered in the pilot plant studies,
 which used actual plating baths that were
 diluted to rinse water concentration, the
 membrane significantly declined in perfor-
 mance at one of the two plants where the
 system was used to treat copper cyanide
 rinse wastewater.   Subsequent laboratory
 investigations indicated that the decline
 in performance was due to some extent to the
 degradation of the spacer (used for flow dis-
 tribution within the module)  by the bright-
 ener additive to the bath.  At the other
 location,  however, the flux and rejection
 achieved by the membrane were relatively
 stable and the system performed satisfacto-
 rily over a sufficient time to conclude  that
 reverse osmosis would be a viable treatment
 approach for copper cyanide rinse waste-
 waters.   The field test on nickel plating
 rinse wastes established the  feasibility of
 using hollow fiber polyamide  membranes for
 treating this  type of rinse water.  More-
 over,  there have been a number  of commercial
 installations  of cellulose acetate  reverse
 osmosis  systems  for the treatment/recovery
 of nickel  plating  rinse wastewaters over
 the past several years,  but the success  of
 this  application has  never been fully doc-
 umented.

      The application  of reverse osmosis  for
 closing  the  loop on metal finishing rinse
 wastes  is  shown on  Figure 1.  Rinse water
 from  the first  tank, which would  otherwise
 be  discharged to the drain, is separated by
 the reverse  osmosis system into a "concen-
 trate" and  "permeate"  stream.   The concen-
 trate stream is returned to the processing
 bath, and  the purified  or permeate stream
 is recycled to the rinsing operation.  A
 small evaporator is required for those metal
 finishing operations where insufficient nat-
ural evaporation occurs in the bath.
       WATER MAKEUP
                                EVAPORATION
                                        DRAG-IN
                        EVAPORATOR
                       (WHERE NEEDED) {
                                   CONCENTRATE
                 PURIFIED WATER (PERMEATE)


                    Figure 1
         REVERSE OSMOSIS RECOVERY SYSTEM
     The major features of reverse osmosis
 as  a treatment device for metal finishing
 rinse waters  are low capital and energy
 costs,  simplicity of operation, and compact
 equipment  requiring a minimum of space.
 The modular nature of these units makes them
 particularly  attractive for small scale
 installations.

     Electrodialysis is an established water
 treatment  and processing technique which is
 now starting  to  receive recognition in the
 industrial waste treatment field.

     Based on a  number of pilot plant in-
vestigations,  the system has been shown
 to be attractive for purifying metal finish-
 ing rinse wastewaters for reuse in the rin-
 sing operations  while concentrating the
 chemicals for return to the processing bath.

     In a. pilot  plant study supported by
EPA, a prototype electrodialysis system was
used to demonstrate  the feasibility of treat-
 ing and recovering  the chemicals from a cop-
per cyanide rinse wastewater.   Figure 2
shows the application of the electrodialysis
system for achieving closed-loop control
of metal finishing rinse wastewaters.
                                            594

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            WORK DRAGOUT
         r—-„	_,

         I
         I
         I
   METAL FINISHING TANK
              I  I
             .j  L.
         ELECTRODIALVSIS UNIT
                             ELECTRODIALYSIS UNIT
                     Figure 2
            ELECTRODIALYSIS RECOVERY SYSTEM
     The  study showed that the chemicals  in
 the  rinse water could be concentrated to
 over 70%  of bath strength.  For copper cya-
 nide plating,  this  level of concentration  is
 sufficient to  return all of the chemicals  to
 the  processing operation since the bath is
 operated  hot and a  significant amount of
 natural evaporation occurs.  The ability  of
 electrodialysis to  achieve high levels of
 chemical  concentrations should permit the
 process to economically close the loop on  a
 number of rinse wastewaters without the need
 for  additional  evaporation.

     There have recently been a few full
 scale installations of electrodialysis in
 metal finishing plants but no data are avail-
 able at this time for evaluating the feasi-
 bility of the  technique for achieving closed-
 loop type control under actual production
 conditions.

 Evaporation

     The  use of evaporation for treating in-
 dustrial  wastewaters  to accomplish water re-
 use  and dissolved solids concentration for
 simplified disposal  or chemical recovery is
 increasing throughout industry in the United
 States.    The evaporative technique has par-
 ticular application  in the inorganic chemical
 industry where  many wastes cannot be effective-
 ly and/or economically treated by the com-
monly used waste abatement methods.   More-
 over, in many cases,  closed-loop type tech-
niques  such as  reverse osmosis, electrodialy-
sis and  ion exchange  cannot achieve  the de-
sired concentration  and require the  use of
an evaporator.
     Based  on  the  success achieved in the
desalting of seawater,  a pilot plant investi-
gation has  been  carried out on a new evapo-
rative technique for industrial wastewater
treatment.  The  approach involves the use of
a small amount of  surfactant to enhance the
heat and mass  transfer  of vertical tube
evaporators while  also  preventing scaling,
fouling and corrosion of the heat transfer
surface.  The  addition  of surfactant to the
feed achieves  enhanced  evaporative heat trans-
fer by maintaining a thinned and agitated
liquid film on the heat transfer surface,
which also  results in increased mass trans-
fer by extending the liquid to vapor sur-
face as shown  on Figure 3.
                                                   UPFLOW VTE WITHOUT INTERFACE ENHANCEMENT
                                                     RESISTANCE TO THE FLOW OF HEAT R
            *
 RESISTANCE TO
 HEAT FLOW
                            UPFLOW VTE WITH INTERFACE ENHANCEMENT
                             RESISTANCE TO THE FLOW OF HEAT R
                   Figure 3

CONVENTIONAL versus INTERFACE ENHANCEMENT EVAPORATION
     The study  involved the use of a 5,000
gal/day pilot plant  having double fluted
aluminum brass  distillation tubes for treat-
ing power plant cooling tower and boiler
blowdown.  The  use of surfactant to achieve
upflow interface-enhanced Vertical Tube
Evaporation provided approximately a 120%
increase in heat transfer compared to con-
ventional operation.  Another important
benefit of the  surfactant addition was its
ability to inhibit the crystallization of
solutes, which  permitted the concentration
of the wastewaters to smaller volumes.

     The results of  this study indicate that
the new approach to  evaporation has consid-
erable potential for the treatment of indus-
trial wastewaters, especially where scaling
may be a problem.  With significantly in-
creased heat  transfer, the size of new
                                              595

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evaporators  can be  greatly reduced or exist-
ing systems  can be  utilized at  much higher
capacities.

Electrolytic Recovery  and  Process  Changes

     A significant  pollution problem at  cop-
per and brass mills is  the disposal of pick-
ling baths when the processing  solution  be-
comes ineffective due  to the buildup of  metal-
lic impurities.  In addition,, large volumes
of dilute rinse waters  containing  acid,  met-
als and other contaminants are  produced  in
the washing  of the  work following  the pick-
ling operations.

     A new approach to  the treatment of  cop-
per and brass mill  wastes  involves  chemical
recovery and water  reuse rather than neutra-
lization and precipitation of the  pollutants
which requires considerable space  and results
in a potentially troublesome sludge disposal
problem.  The effectiveness and economics  of
the new technology  has  been demonstrated on
full scale at a plant producing 75  tons  of
copper and cuprous  alloy per day which used
a hot sulfuric acid primary pickle  followed
by an ammonium bifluoride  secondary pickle.

     The novel treatment approach,  which is
shown on Figure 4,  involved (1)  the instal-
lation of an electrolytic  copper recovery
system in the primary bath to recover the
copper and continuously purify  the  sulfuric
acid solution, (2)  the  replacement  of the
chromic acid - ammonium bifluoride  secondary
pickle with  a hydrogen  peroxide    sulfuric
acid secondary pickle containing proprietary
additives, and (3)  the  incorporation  of  an
integrated chemical  rinse  system to  wash the
wire prior to fresh  water  rinsing.   The  hy-
drogen peroxide oxidizing  treatment  in the
secondary pickling  bath results  in  the for-
mation of water and  a cupric  sulfate  buildup
which is periodically removed by simple
crystallization and  added  to  the electrolytic
recovery system or  sold separately  as  a  by-
product.   The integrated chemical rinse  is a
recycle system in which the copper  in the
pickling solution washed from the wire is
precipitated by the  alkalinity  in  the rinse
water and settled as a  salable  dense sludge
in a reservoir tank.
         REUSE WATER LINE
               • 		1 pLlli wwicn        urc
               ,R20Z STABILIZER INHIBIT Hi I     	FROM DE_IONIZER r
             P?  ri'iO^ill^n.l^ii-j
                                       to DRAWING
                                       OPERATION
                  SETTLING TANK   FINAL pH ADJUSTMENT TANK
                    Figure 4

       PICKLING OPERATIONS, COPPER RECOVERY,
       WASTE TREATMENT & WATER REUSE SYSTEM
     The application of the  recovery  approach
has demonstrated a reduction of metal  losses
from 600-700 to less than  one pound per  day
and water consumption from 200,000 to  20,000
gallons per day by chemical  rinsing and
water reuse.  Therefore, the new  pollution
abatement system has eliminated the dumping
of spent pickling baths and  the discharge
of such troublesome contaminants  as chromium,
ammonium and fluoride, while permitting  the
recovery of essentially all  of the copper as
well as reuse of about 90% wastewater.

     The company estimates that when  the
cost of pickling and waste treatment  for the
new approach is compared with the pickling
and waste costs of conventional  chemical
treatment, a substantial savings  has  been
achieved -- a daily cost of$194  compared
with $540 for conventional abatement.

                SUMMARY

     In summary, new wastewater  treatment
technology  is emerging for chemical  recovery
and water reuse but the  extent of develop-
ments  is relatively slow  in  comparison to
the overall needs  of the Nation,  primarily
because of  the complexity  of industrial pol-
lution problems.   By continuing  to support
                                             596

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research,  development and demonstrations of
innovative technology, as described in this
paper,  the U.  S.  Environmental Protection
Agency intends to play a significant role
in the effort  of attaining the national
goal of zero discharge.
                                           597

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                          STATUS OF INSTRUMENTATION AND AUTOMATION
                         FOR CONTROL OF WASTEWATER TREATMENT PLANTS

                                      J.  F.  Roesler
                         MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
                             OFFICE OF RESEARCH AND DEVELOPMENT
                            U.S. ENVIRONMENTAL PROTECTION AGENCY
                                  CINCINNATI, OHIO  45268
                                         ABSTRACT

     This paper addresses the questions about the effectiveness of instrumentation and
automation that is being used in wastewater treatment.   A user survey of the instruments
and automatic controls being used in 50 wastewater treatment plants is described.  The
instruments were evaluated on the basis of their usage and reliability.  Automatic control
strategies were evaluated on the basis of their performance improvement and cost effective-
ness.  Specific examples of control loops are described as implemented at Renton, Washing-
ton; Palo Alto, California; and the U. S. Environmental Protection Agency pilot plant at
Blue Plains Washington, D.C., automation for both biological and physical-chemical treat-
ment is discussed.
               INTRODUCTION

     The objectives of the instrumentation
and automation of any process are to
improve the reliability of maintaining a
consistent product quality, enhance process
performance and reduce costs.  The concept
of applying instrumentation and automation
to wastewater treatment is still relatively
new, and as a result many questions must be
answered.  Some of these questions are:  1)
what equipment is currently being utilized,
2) how effective is automated control and
3) what are the problems that must be over-
come to promote automation?  Once the
answers to these questions are known,
productive utilization of instrumentation
and automation must be promoted.

     In this paper an attempt will be made
to answer these questions by describing
some of the U. S. Environmental Protection
Agency (EPA) research results.  This
research involves an EPA sponsored user
survey of 50 wastewater treatment plants,
the evaluation of several control strategies
at Palo Alto, California, inhouse efforts
evaluating dissolved oxygen  (DOJ control at
Renton, Washington and EPA pilot plant work
on physical-chemical treatment in Washing-
ton, D.C.  To maintain communication with
the user community the establishment of an
EPA advisory committee is also described.

               CURRENT STATUS

     In order to answer the first question,
a user survey of 50 wastewater treatment
plants (1) was conducted.  Each plant was
personally visited by the interviewer who
determined the type and extent of usage
of instruments and automatic controls.  In
each plant the operational personnel were
asked to give an estimate as to the effect-
iveness of the sensor or control loop.  The
degree to which each instrument was used in
each plant and the operator's responses
were used to determine the effectiveness of
the equipment.

     The present use of specific types of
sensors was evaluated by considering the
distribution of all types of sensors in all
50 plants as shown in Figure 1.  Every
                                           598

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plant had some device for monitoring flow.
Thus 30% of all the instruments in all of
the plants were for flow measurement
(Figure 1).  Automatic analyzers were the
next highest category probably because this
category included, turbidity, conductivity^
    * AUTOMATIC ANALYSIS
             29%
     * NON-LABORATORY PROCESS INSTRUMENTS ONLY


  Figure 1. Observed distribution of measuring instruments
pH, DO, chlorine and other analyzers.  The
miscellaneous analyzers section that is in-
dicated in Figure 1 include such analyzers
as rotational speed, weight, and position,
etc.

     In Figure 2, the instruments observed
during the survey are summarized according
to the criteria of unsatisfactory
(abandoned equipment),  fair (performance
considered marginal or excessive mainten-
ance  is required) and satisfactory.  Note
that with the exception of such devices  as
the bubbler-type level detectors, Venturis,
temperature guages, etc., most instruments
suffered a 31% less than fair performance
record.  Furthermore, instruments manufac-
tured by the same manufacturer and of iden-
tical model were abandoned at some loca-
tions but were utilized at other locations.
Note also that complicated equipment, such
as the TOC analyzers grouped in the  "other
analytical analyzers" section, suffered
very high failure rates.  Simple equip-
ment such as bubbler-type level detectors
performed well and were well integrated
into automatic control systems as shown  in
Figure 3.  Here liquid level is the most
popular of all observed control schemes.
With the exception of computers, as the
control scheme becomes more complicated
the number of poor experiences increase.

 AUTOMATION OF ACTIVATED SLUDGE PROCESSES

     To  answer the second question as to
the effectiveness of automation, more
detailed studies are necessary.  The
technique usually  suggested for such an
evaluation is the  comparison of the  per-
formance of the plant under automatic
control with that of manual operation.
However, the standards  for manual oper-
ation vary according to the idiosyncrasy
of each plant and of each operator.  It  is
therefore, necessary that the manual oper-
ation be well defined and rigidly enforced.
Two studies that meet these requirements
were carried out at Renton, Washington  (2)
and Palo Alto, California  (3).

     The Renton plant was operated for
about a year  (March 1970 to April 1971)
under manual control while an automatic
DO control system was being installed
into a new aerator.  The following
year, the plant was successfully operated
with automatic DO control.  Data were
collected for comparative purposes during
the months of October, November and
December for years 1970 and 1971.  The
operators and plant management had an
excellent attitude toward automation.
Also, the manual control policy was  well
defined  and expertly carried out.

     The obvious question, however,  is
whether the sewage was  identical for both
time frames.  One partial answer is  that
the BOD  loading to the plant increased
about 50% during the automatic control
                                            599

-------
               10
1972-3
15
  20
25
NO. OF CASES
  30       35       40
                       BUBBLER-TYPE LEVEL DETECTORS
                  DIFFERENTIAL-PRESSURE LEVEL DETECTORS
                  FLOATS
                  ALL OTHER LEVEL DETECTORS
                            I     WEIRS AND FLUMES
                 VENTURIS, ORIFICES, NOZZLES
                 MAGNETIC FLOWRATE
                         OTHER FLOWRATE METERS
                               I   NUCLEAR RADIATION DENSITY METERS
                   TRANSMITTING RAIN GAUGES
                                I  TEMPERATURE
                         PRESSURE
              ROTATIONAL SPEED
                         WEIGHT
                  |       POSITION
                     I    TURBIDITY
                         CONDUCTIVITY
                          I        PH AND ORP
                          THALLIUM DO PROBE
                         ^]       MEMBRANE DO PROBE
                                I  RESIDUAL CHLORINE
                         OTHER ANALYTICAL ANALYZERS
                            I      GAS MONITORS
                        ]         SAMPLING SYSTEMS
       UNSATISFACTORY
FAIR
                   SATISFACTORY
Figure 2. Performance summary of measuring devices in wastewater- treatment facilities
                                600

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                                1972-3
                        IMO. OF CASES
                   10
15
20
25
30
35
                           LIQUID LEVEL CONTROL
         LIQUID FLOWRATE CONTROL
                        SLUDGE PUMPING
              AIR FLOWRATE
        CHEMICAL ADDITION
       RESIDUAL CHLORINE
                           DISSOLVED OXYGEN



                           PH



                           TURBIDITY




                           AUTOMATIC  SCUM REMOVAL








                           AUTOMATIC DATA ACQUISITION



                           SUPERVISORY COMPUTERS




                           DIRECT PROCESS CONTROL BY  DIGITAL COMPUTER
            UNSATISFACTORY
            FAIR
             SATISFACTORY
Figure 3. Summary of automatic control experiences in wastewater- treatment facilities
                                  601

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period.  In spite of this increase, the
performance of the plant did improve.  The
effluent BOD decreased from a geometric
mean of 11.1 ppm, obtained during manual
operation, to a mean of 3.9 ppm for auto-
matic operation.  Figure 4 shows the
effluent BOD data plotted on logarithmic
probability paper to obtain a frequency
distribution of measurements.  The slope of
the lines reflects the degree of reliabil-
ity.  For example, in Figure 4 the reduced
slope of the automatic control line indi-
cates that automation will result in
tighter control of effluent BOD.

     Further analysis indicated that the
sludge characteristics may also have been
affected by automatic DO control.  The
frequency distribution of the sludge
volume index (SVI) is shown in Figure 5.
The arithmetic mean for the SVI with manual
control was 332.  This was reduced to 86
with automatic control.   The difference in
the slopes of the two lines is more marked
in this case (Figure 5)  indicating a greater
advantage for automatic control in main-
taining a consistent product.

     At Palo Alto the computer calculated
the DO setpoints using data obtained from
DO probes and then alerted the operator to
make the required change.   In contrast
during the manual operation, the operator
monitored the DO twice per shift and then
made the appropriate corrections.  When
the semi-automatic operation was compared
to manual operation (Figure 6), a 13%
performance improvement  as measured by
effluent TOG and an 11%  reduction in air
use was observed.  The latter calculates
to a $5,380 savings per  year for a 25 mgd
plant.   When a cumulative  frequency plot is
made of manual vs. DO control,  the slopes of
the lines were equal indicating that the
reliability of both systems was similar.
This is understandable since the final
control implementation was carried out by
the same operators.

     The other control strategies that
were evaluated at Palo Alto concentrated on
regulation of food-to-microorganism ratio
(F/M).   Several techniques such as TOG, COD
and oxygen uptake were considered for
measuring the food.   However, suitable
automatic TOG and COD analyzers were not
available for on-line control during the
Palo Alto experiments.  Therefore, only two
F/M control strategies could be evaluated.
These were a) feedback respirometry  control
using an on-line respirometer, and b)  DO/
RAS control.  In both cases the DO was  con-
trolled as described previously and  since
the results were similar only DO/RAS con-
trol loop will be described.

     For DO/RAS control, the rate of air
demand was assumed to be proportional  to
the BOD input and the return sludge was
adjusted to maintain the desired F/M ratio.
In other words, the entire aeration tank
was used as a respirometer to set the
return sludge flow.

     In all these evaluations, the system
was allowed about 30 days to stabilize, and
then, three days of intensive sampling was
carried out.  Figure 7 shows the BOD load-
ing (food uptake) that was measured every
two hours.  Using the aeration tank as a
respirometer the food uptake was also
estimated and compared to the BOD loading.
Under manual operation, that is, maintain-
ing a constant RAS, the mixed liquor susp-
ended solids (MLSS) varied widely as shown
in Figure 8.  When DO/RAS control is
employed, the MLSS becomes more constant
(Figure 9).  However, when comparing
these results to those obtained when only
DO control was used the plant showed no
performance improvement in terms of
effluent quality or cost savings.

     The results do indicate that DO control
is a valuable control loop that should
be explored further.  The ease and sim-
plicity of installing and maintaining a
DO loop is more than compensated for by
the cost savings and performance improve-
ments.  The case for F/M control however,
is not so conclusive.  Because of fund
limitations, the evaluations at Palo Alto
were limited to about 30 days each.  There
is some speculation that had more time
been allowed, especially for manual eval-
uations, more significant results could
have been obtained.

      AUTOMATION OF PHYSICAL-CHEMICAL
            TREATMENT SYSTEM

     The basic physical-chemical process
sequence that was evaluated at Blue  Plains
(4) is shown in Figure 10; it consists  of
two-stage  (high pH) lime precipitation
with intermediate recarbonation, dual-
media filtration, pH control with chlorine,
CO- stripping, breakpoint chlorination and
                                            602

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100.0
 90.0
 80.0

 70.0

 60.0

 '50.0
 30.0
 20.0
 10.0
  9.0
  8.0
  7.0

  6.0

  5.0
                        FIGURE 4  FREQUENCY DISTRIBUTION OF  BOD IN THE  EFFLUENT
     99.99   99.9 99.8 99.5 99  98    95   90    80   70  60  50  40   30   20     10    5     21  0.5  0.2 0.1 0.05 0.01
  2.0
I    I
                   I   I    I
                      I
T   T
I    l
l
                                                               AUTOMATIC CONTROL
                           J	I
           J	l
        0.050.1 0.2  0.5   1
                                               30  40  50  60   70
                                                                 80
                                                                       90
                                                                            95
                                                                                 98  99 99.5 99.8 99.9
                                                                                                       99.99
                 PERCENT  OF OBSERVATIONS EQUAL TO  OR LESS  THAN  STATED CLASS MEAN

-------
1000 i
900
800
700
600
500

400

300
                              FIGURE 5    FREQUENCY  DISTRIBUTION OF SVI
           99999.8  99.5 99  98
                                 95    90
                                            80   70  60  50 40  30   20
                                                                          10
                                                                                         1  0.5  0.2 0.1 0.05   0.01
 100
 90
 80
 70
 60
 50
I    I
            I
                       I
                                   I    __
                                            AUTOMATIC CONTROL
         I
I
I
I
                                                                                                 I
   0.01  0.05 0.1 0.2   0.5  1    2     5     10     20   30  40  50  60  70   80     90   95    98  99  99.5 99.8 99.9
                      PERCENT OF OBSERVATIONS EQUAL TO OR LESS  THAN STATED CLASS MEAN
                                                                                                            99.99

-------
ON
O
Ul
                     100

                  ^  80
                   tofl

                   "  ••


               i- S  40
                      20
                   CO
               CJ
               LU

                   GO

                   CO
                                                             I    I    I
                       0.2     1      5   10   20  30 40 50 60 70 80   90   95     99   99.8

                                         CUMULATIVE FREQUENCY, %

                     FIGURE 6. DRY SEASON TESTS: SECONDARY EFFLUENT SUSPENDED  SOLIDS

                              CONCENTRATION  VS. LOG NORMAL FREQUENCY DISTRIBUTION

-------
                       40,000
                       30,000
                       20,000
o\
o
                        10,000
                           0
                                 6
   12    18
SUNDAY
2/10/74
o
6
0
6
                               12    18
                             MONDAY
                             2/11/74
                         DATE-TIME OF DAY
FIGURE  7  . AIR/RAS CONTROLLER: ACTUAL AND ESTIMATED FOOD  UPTAKE
   12    18
TUESDAY
2/12/74
o

-------
              20 -
                                            2000
O^
O
              16
              12
                                                            RAS
                                            1500
MLSS
                                                          ' \
                                                        '

                                                             V
                                                                          1000
                                                                          500
                                                                               00
                                                                               oo
                     6    12    18
                       SUNDAY
                      11/25/73
         6   12    18
           MONDAY
          11/26/73
6    12    18
  TUESDAY
  11/27/73
                                     DATE-TIME OF DAY
                    FIGURE 8 MANUAL TEST II: MLSS AND RAS VS. TIME

-------
              CD
O
oo
              CD
              OO
                  20
                  16
                  12
                                                         MLSS
                                                          2,000
                                                          1,500  _
                                                               toJO
                                                                                      1,000
                                                                                      500
                                                                                           oo
                          6     12    18
                            SUNDAY
                            2/19/74
              0     6    12    18    0
                     MONDAY
                     2/11/74
                 DATE-TIME OF DAY
FIGURE  9, AIR/RAS CONTROLLER: MLSS AND RAS VS.  TIME
6    12    11
  TUESDAY
  2/12/74

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        LIME SLURRY
      -i    H
           LTU
        LIME  SLUDGE
PRODUCT
        CARBON
      ADSORPTION
                          C02-
      r
                                      FeCL3
                                    LTTJ
             LIT]
                           BASE
 BREAKPOINT
CHLORINATION
                                       CL2
                                                        U
                                                     LIME SLUDGE
                   L
       J   L
                                                               J
DUAL-MEDIA
FILTRATION
                                FIGURE 10
                     PHYSICAL CHEMICAL TREATMENT
                     TWO-STAGE CHEMICAL CLARIFICATION
                     WITH INTERMEDIATE RECARBONATION
                                609

-------
granular carbon adsorption.  In the first
stage of the process, powdered lime, raw
wastewater, and recycled solids are
rapid-mixed, flocculated and settled to
remove bicarbonate, phosphate and
magnesium.   The pH of the clarified
effluent is reduced from 11.5 to 9.5 in a
recarbonation tank.  The effluent from the
second stage clarifier flows by gravity
through dual-media filters consisting of
coal and sand.  After filtration, chlorine
is added in a static mixer to reduce the
pH to 6-7.   Carbon dioxide is air stripped
from the filter effluent to reduce the
alkali required for the breakpoint
reaction.  Breakpoint is achieved by add-
ing chlorine and alkali to the wastewater
ahead of a second static mixer and con-
tact tank.   The base is added to control
the pH and prevent formation of undesir-
able end products such as nitrate and
nitrogen trichloride.  Soluble residual
organics are removed from the wastewater
with two-stage downflow carbon columns
using a contact time of 40 minutes.  A
high quality effluent is produced by this
treatment sequence.  Typical water quality
includes 5 mg/1 of BOD, 15 mg/1 of COD,
0.15 mg/1 of P and 2.6 mg/1 of N (3).

Lime Clarification

     A dry lime feeder maintains a constant-
concentration lime slurry which is cir-
culated through a head tank above the
primary reaction zone of the clarifier.
An electro-pneumatic valve meters the slurry
into the reaction zone on demand signals
from the lime-feed controller.  The four
alternative strategies studied for lime-
feed control were 1) conductivity-ratio,
2) flow-proportional, 3) pH plus flow-
proportional, and 4) alkalinity plus flow-
proportional.

     Figure 11 schematically represents the
basic components used in the four alter-
native control schemes.  The conductivity-
ratio control scheme involves the measure-
ment of conductivity in the primary
reaction zone and in the influent waste-
water.  The ratio of these conductivity
measurements generates a control signal
(C) for the lime-feed valve.  For flow-
proportional control, the influent flow
rate is measured, and this signal (properly
modulated at MT and PS) is transmitted
directly to the control valve.  For pH plus
flow-proportional control, the pH is
measured in the primary reaction  zone,  and
this signal is used to adjust  the signal
generated from the flow-proportional  loop.
For alkalinity plus flow-proportional
control, a sample is pumped  from  the
clarified zone of the clarifier through a
porous rock filter to an automatic titrator.
The resulting alkalinity signal is trans-
mitted to the multiplying transmitter in a
flow-proportioning control system for final
adjustment of lime addition.

     The results of a seven-day test run
are shown in Table 1.

TABLE 1.  PERCENTAGE DEVIATION FROM TARGET
          DURING SEVEN-DAY TEST RUN
Control Scheme
  Ranges of Deviation
from Target Alkalinity, %
Conductivity-ratio         + 16 to -20
Flow-proportional          + 15 to -15
pH plus flow-proportional  + 10 to -10*
Proportional               + 10 to -15t
Alkalinity plus flow-
 proportional              +7.5 to -7.5


*lst 2 days
tEntire 7-day test period.

     Conductivity-ratio control was found to
be the least accurate control system, but it
would be a good backup control system since
it is dependable and the equipment requires
little maintenance.  The flow-proportional
control system was very sensitive to any
change in lime-slurry concentration and was
very much dependent on the accuracy of the
flow measurement device.  After seven days
of operation, the pH electrodes were coated
with a calcium carbonate scale which was
approximately 1/16-inch thick.  This
coating was removed in 2% hydrochloric acid,
and the electrode regained its initial res-
ponse characteristics.  By scheduling
electrode cleaning every 2 days, pH control
will work satisfactorily.  Placement of the
pH probe in a separate rapid-mix tank
reduces the maintenance requirements as-
sociated with placement in the primary
reaction zone of a single-unit clarifi-
cation system.

     While alkalinity plus flow-proportional
control produced the closest alkalinity
control of all the systems studied, the
                                           610

-------
 LEGEND:
 T = Reference Transducer
MT = Multiplying Transducer
 C = Controller
SC = Signal Conditioner
AD = Measuring Transducer
      (Analytical Device)
PS = Pulse Transmitter
                            influent
                 REQUIRED COMPONENTS  FOR CONTROL SCHEMES
              TYPE  OF CONTROL
            CONDUCTIVITY RATIO
            FLOW-PROPORTIONAL
         pH PLUS FLOW-PROPORTIONAL
     ALKALINITY PLUS FLOW-PROPORTIONAL

         FIGURE 11
LIME FEED CONTROL SCHEMES
   COMPONENT
   T  AD   C
   T   MT   PS
AD   SC   C  MT
T  MT  AD   PS
PS

-------
equipment malfunctioned repeatedly be-
cause of filter clogging.   The inability
to filter high solids concentrations
efficiently required relocation of the
sample point from the reaction zone to
the clarified zone.  This  resulted in a
two-hour lag in the response time which
caused large swings in process effluent
quality when the lime-slurry concentration
changed.  Until the solids handling problem
for alkalinity plus flow-proportional
control is solved, the recommended control
system is pH plus flow-proportional, with
conductivity-ratio control as a backup.

     The solids wasting control loops for
the first and second stage clarifiers are
simple feedforward systems where periodic
pulses, proportional to flow, produce a
discharge.  The discharge from this tank
is controlled by a level switch sensing the
fixed volume.

     The control loop for the Fed, feed in
the recarbonation tank is a feedforward
flow-proportional system which changes the
duty cycle of the dosing pump.

     The carbon dioxide dosing control sys-
tem is the same pH plus flow-proportional
control system used for the lime addition
control.  The chemical dose is controlled
by a feedforward signal proportional to
flow and a feedback signal generated by
pH error.

Filtration

     Operation of the dual-media gravity
filters was controlled with four, alterna-
tive, backwash initiation and control
schemes.  Alarm schemes used to initiate
backwash had time-delay circuits to prevent
accidental or momentary events from
triggering the backwash cycle prematurely.
The four models used were 1) headless,
2) high-level  (influent level), 3) pro-
grammed time-interval, and 4) manual.  The
headless sensor initiates the backwash
cycle when the available head decreases to
a preset minimum valve (H.L. = 9 ft FLO).
When the level tends to change, the high-
level indicator opens an effluent control
valve so that a constant level is main-
tained.  When the control valve is  100%
open, backwash is initiated.  The pro-
grammed time-interval controller will
initiate backwash at the expiration of a
preselected number of operating hours.
The operator may over-ride any of the above
controls at any time with the manual mode.

     The effluent from clarification was
distributed equally to the operating
filters by a mechanical splitter box.  As a
filter was isolated for backwash, the flow
to that filter was redistributed to the
remaining operating filters.  If the head-
loss alarm was used and if the filter
backwash occurred at peak flow rates, the
redistribution caused the already stressed
operating filters to be overstressed.  The
final result was a chain reaction result-
ing in the need to backwash all available
filters in a relatively short period of
time which increased the requirements for
backwash-water pumps and storage capacity.

     The programmed time-interval controller
was used to schedule filter backwashing at
different hours during periods of low flow;
this reduced backwash-water pumping and
storage requirements, and it eliminated
overstressing of the system.  The headloss
indicator was then used as a backup alarm
to prevent flooding when system upsets
caused increased solids loading and short-
er filter runs than the programmed time
interval.  The high-level alarm was
connected to an audio-visual alarm and was
used to indicate equipment failure.  This
system has provided peak operating
efficiency at the lowest possible operating
cost.

Breakpoint Chlorination

     The control scheme developed to con-
trol the breakpoint-chlorination process is
shown schematically in Figure 12.  The
chlorine dosage-control loop employs a
feedforward signal proportional to the mass
of influent ammonia and a feedback signal
based on the free residual chlorine con-
centration error.  The feedforward signal
is derived from the concentration of
ammonia in the influent, the influent
flow rate, and a preselected weight ratio
of chlorine to ammonia.  If digital con-
trol of the system were practiced, this
feedforward signal would be adjusted by the
amount of chlorine used for pH control
during prechlorination.  The control loop
for alkali addition  (NaOH) is derived from
a feedforward signal based on the  chlorine
dosage used and a feedback signal based
on the pH error.  The on-stream  analysis
of ammonia by a chlorimetric analyzer,
                                            612

-------
influent
effluent
                                        FT = Flow Transducer
                                        RT = Ratio Transmitter
                                       CCV = Chlorine Control  Valve
                                       pHC = pH Controller
                                       pHT = pH Transducer

                                       FIGURE  12

                        BREAK  POINT  CHLORINATION  CONTROL
   AT = Ammonia Transmitter
  BPC = Break point  controller
pH CV = pH Control Valve
   SC = Signal Conditioner
  CAT = Chlorine Ammonia
        Transmitter

-------
both before and after breakpoint chlorin-
ation, has been accurate and dependable.
Free residual chlorine is also continu-
ously measured by a colorimetric analyzer.
Preliminary operating experience has been
favorable.  Breakpoint chlorination reduces
operating problems with the carbon adsorp-
tion system by reducing biological slime
growths.  The carbon adsorption process is
a good backup system for the breakpoint
chlorination process because of the de-
chlorination potential.

Carbon Adsorption

     The carbon adsorption process pre-
sented control problems very similar to the
filtration system; however, the carbon ad-
sorption process was only semi-automated.
A level-controller regulated the flow
through the system, while an automatic
pressure-controller on the discharge side
of the carbon-column feed pump maintained
a constant pressure at the inlet to the
first carbon column.  There were five
carbon columns interconnected in series by
headers and automatic valves to allow any
number of columns to be operated in se-
quence and any column to be the lead
column.  Column sequencing and backwash
initiation were determined by an operator.
The lead column is backwashed daily in
the raw wastewater-treatment applications.

Direct Digital Control

     An IBM Systems/7 computer was in-
stalled at the EPA Blue Plains Pilot Plant
to provide total systems control for the
independent physical-chemical treatment
sequence  (5).  The process-control com-
puter also performed a data-acquisition
function.  Plant data from approximately
100 wastewater-process sensors were
collected, converted into engineering units
and stored for later analysis and eval-
uation of the systems performance.

     Alarm modes were also included to
alert the operator of plant conditions that
require his attention and correction.
Examples are out-of-range alarms for such
parameters as pH and chemical doses to the
wastewater, as well as equipment-failure
alarms for such items as sludge-blowdown
equipment and pneumatic pumps.

     Direct digital computer control is
being used more frequently in the larger
wastewater treatment facilities where  the
economies realized in data acquisition,
reporting, preventive maintenance  sched-
uling, load programming and improved per-
formance can offset the additional  costs of
specialized manpower and the capital costs
of the initial hardware and backup  system.
The capability to control individual unit
processes and indeed complete physical-
chemical treatment systems is rapidly  be-
coming a reality.

   RESEARCH NEEDS AND PROBLEM AREAS

     To initiate a coordinated attack  on
instrumentation and automation problems in
this field, a workshop entitled Research
Needs for Automation of Wastewater Treat-
ment Systems (6) was held in Clemson,
South Carolina in September 1974.  This
workshop, sponsored by the EPA in cooper-
ation with Clemson University, provided an
opportunity for workers in this area to
discuss their research problems and needs.

     The workshop found that the general
problem areas were the lack of:  adequate
field experience, quantitative understand-
ing of wastewater systems, and required
sensors.  Or to put it another way, the
problems are a lack of sensors and of  fun-
damental knowledge about the treatment
processes.  These problems were stated in
almost every session.   To resolve these
problems, the needed research should in-
clude demonstrations of automated process
control, development of mathematical
models and algorithms, and evaluation  of
sensors.  The workshop also indicated  a
need for an information clearinghouse, in-
cluding the international exchange of  data;
and projected a new philosophy of waste-
water renovation as opposed to processing
wastewater to minimum quality requirements.
The cost-effective application of instru-
mentation and automation to wastewater
management systems will be a key to imple-
menting this philosophy.  One immediate
outgrowth of the workshop was the establish-
ment of an EPA Advisory Committee on
Instrumentation and Automation for Waste-
water Management.  The functions of this
advisory committee will be to:
                                            614

-------
   o  serve as focal point for questions
      concerning instrumentation and auto-
      mation of wastewater management
      systems within the United States,
      and provide liaison with similar
      groups in other nations

   o  facilitate the exchange of research
      information in this area

   o  identify and characterize the tech-
      nology required for instrumentation
      and automation of wastewater manage-
      ment systems

   o  assist the EPA in defining short-
      and long-range research development
      and demonstration programs

The roster of this advisory committee
consists of four EPA members and eight non-
EPA members.  The latter represent state
and local governments, the academic
community, equipment manufacturers and pro-
fessional societies.  The communication
resulting from such a widely represented
group is desirable because it establishes
a link between the user community, the
researcher and enforcement agencies.
This provides for the opportunity for each
of these groups to rapidly communicate
goals, problem areas and solutions with
one another.

              REFERENCES

1.  Molvar,  A.J., et al., "Instrumentation
      and Automation Experiences in Waste-
      water Treatment Facilities."  EPA
      report being prepared for
      publication.

2.  Roesler, J.F.,  "Plant Performance Using
      Dissolved Oxygen Control."  Jour.
      Environ.  Eng.  Div., 100,  1069 (1974).

3.  Petersack,  J.F.  and Smith,  R.G.,
      "Advanced Automatic Control
      Strageties for the Activated Sludge
      Treatment Process."  EPA-670/2-75-039
      (May 1975).

4.   Convery, J.J.,  et al.,  "Automation and
      Control of Physical-Chemical Treat-
      ment for Municipal Wastewater."
      Applications  of New Concepts of
      Physical-Chemical Wastewater Treat-
      ment,  Sept.  18-22, 1972.  Pergamon
      Press, Inc.  USA (1972).
Bishop, D.F., et al., "Computer Control
  of a Chemical Clarification Waste
  Treatment Pilot Plant."  Presented
  at the First International Meeting
  Pollution:  Engineering to Scientific
  Solutions, Tel Aviv, Israel (June 12-
  17, 1972).

Buhr, H.O., et al., Ed.  "Research Needs
  for Automation of Wastewater Treat-
  ment Systems."  Proceedings of a
  Workshop held at Clemson,  S.C.
  September 23-24, 1974  (June 1975).
                                           615

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                       RESEARCH REQUIRED TO ESTABLISH CONFIDENCE
                          IN THE POTABLE REUSE OF WASTEWATER

                      J.N.  English,  K.D.  Linstedt, and E.R. Bennett
                       J.N.  English, Sanitary Engineer, Wastewater
                  Research Division, Municipal Environmental Research
                Laboratory,  EPA, Cincinnati 45268; and  K.  D.  Linstedt
                  and E.  R.  Bennett  Associate Professors of Sanitary
                      Engineering at the  University of Colorado
                                 Boulder,  Colorado   80302
                                        ABSTRACT

     A Municipal Research Needs Workshop,  sponsored by the Environmental Protection
Agency (EPA), the Water Pollution Control  Federation (WPCF),  and the American Water Works
Association (AWWA),  was held at the University of Colorado, Boulder, Colorado, in March
1975 to identify priorities for research that would provide scientific knowledge and
technology to prove the feasibility and practicability of reusing wastewater.s for potable
purposes.  Ninety-two select persons concerned with municipal wastewater reuse in the
United States and abroad discussed and identified a long term research program involving;
treatment technology; treatment reliability and quality control; health effects associated
with organic, inorganic, and biological pollutants; and the socio-economic aspects of
potable reuse.
                BACKGROUND

     Sound management of water resources
must include consideration of the potential
use of properly treated wastewaters as an
alternate means of meeting future water
demands.  Consumptive water use data
indicate that the lower Colorado River
region uses more water than its available
natural supply, and the Great Basin and
Rio Grande regions use 60 percent or more
of their average supplies (1).  Large,
economically important regions of the
Nation already are, or will be using water
beyond the capacity of the available nat-
ural water resources.  Steadily increasing
municipal and industrial water require-
ments in these areas, combined with
expanding irrigation activities, could
place severe strains upon limited water
resources.  At the same time, many areas
are facing the growing problems of water
quality deterioration.

     Groundwater in many areas is being
mined or used at rates exceeding recharge
capability.  The present economy of these
areas is based upon the foundation of a
temporary and dwindling water resource.
In major groundwater-using areas, such as
Lond Island and Southern California,
substitute supplies can be obtained only
at relatively high cost.  Where water
development costs and legal constraints
are making sources of raw water difficult
to acquire, wastewater reuse is an attrac-
tive alternative water source.  In addi-
tion, reuse is an effective method of
dealing with water pollution by preventing
degradation of water quality.

     Public Law 92-500, the Federal Water
Pollution Control Act Amendments of 1972,
recognizes the potentially large benefit
to be realized if wastewaters can be
renovated for reuse applications.  The
Safe Drinking Water Act of 1974 also con-
tains mandates of importance with regard
to renovation and recycling of wastewaters.
In particular, Section 1444 authorizes a
development and demonstration program  to:
(1) investigate and demonstrate health
                                          616

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implications involved in the reclamation,
recycling, and reuse of wastewaters for
drinking; and (2) demonstrate processes
and methods for the preparation of safe
and acceptable drinking water from waste-
waters.  There exists, therefore, a strong
and clear legislative mandate for research,
development, and demonstration of reliable,
cost-effective technology for reclaiming
and recycling wastewaters for beneficial
uses.  A major beneficial use is the sup-
plementation of domestic water supplies.

     Advanced wastewater treatment systems
developed primarily for pollution control
are available for removing pollutants to
very low levels.  As a result of this
technology, and the need for additional
sources of water to meet present and
future requirements, renovated wastewater
is being considered in planning for over-
all water resources utilization in many
areas of the country.  The treatment tech-
nology capability can be identified for
reuse applications such as agricultural,
recreational, and industrial where quality
requirements have been defined.  The State
of California has already established
water quality standards for wastewater
used for agricultural and recreational
purposes  (2).  Since there are public
health questions in this country concern-
ing the degree and reliability of treat-
ment for potable reuse, the necessary
treatment technology is less well defined
for this use than for other types of
reuses.
     Because of the limited experience
with direct or overt potable reuse of
renovated wastewater there are no stand-
ards to apply to such waters.  The U.S.
Public Health Service (USPHS) Drinking
Water Standards of 1962, and the Environ-
mental Protection Agency (EPA) Proposed
Interim Primary Drinking Water Standards
apply to water sources that are as free
as possible from pollution.  The concern
among many in the water field over the
uncontrollable source and characteristics
of wastewater has resulted in the recom-
mendation that renovated wastewater should
meet stringent standards in addition to
those written for unpolluted sources.
This concern would appear to be reasonable,
but should not be restricted to waste-
water since many surface water supplies
do not qualify as "unpolluted."

     Health effects research relating to
wastewater reuse has not paralleled the
developments in wastewater treatment tech-
nology.  The quality of present conven-
tional water supplies has only been
questioned rather recently relative to the
trace contaminants.  Health effects studies
are presently underway on approved sources
of potable water.  However, much remains
to be done since many problems, such as the
presence of organic materials and their
potential health hazards in drinking waters,
have not been solved.  This needed research
will be applicable to wastewater reuse
since the production of water from surface
supplies that contain a significant portion
of effluents is analogous to the direct
recovery of water from wastewater.

     In addition, research to determine the
economic, social, and political aspects of
potable reuse has not kept pace with treat-
ment technology development.  The EPA has
only recently identified needed information
in this area, and this has come about as a
result of the potential availability of
highly treated wastewaters that are "too
good to throw away."  These waters have
attracted the attention of those agencies
in water-short areas that are responsible
for maintaining adequate supplies of
drinking water.

        RESEARCH NEEDS WORKSHOP

     The Water Pollution Control Federation
(WPCF) and the American Water Works Assoc-
iation (AWWA) issued a joint resolution
that urged the Federal Government to sup-
port a massive research effort to develop
needed technology for the potable reuse of
wastewater.  These organizations under-
scored the "lack of adequate scientific
information about possible acute and long-
term effects on man's health from such
reuse," and noted that "essential fail-safe
technology to permit such direct reuse has
not yet been demonstrated."  The resolution
recognized the need for an "immediate and
sustained multi-disciplinary, national
effort to provide the scientific knowledge
and technology relative to the reuse of
water for drinking purposes in order to
assure the full protection of the public
health."

     The EPA Office of Research and Devel-
opment (OR&D), through its Municipal
Pollution Control Division, has devoted
effort for a number of years to the devel-
opment of wastewater treatment processes
capable of producing high quality effluents
                                          617

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suitable for a range of reuse or recycling
applications.  More recently the OR&D
Health Effects and Socio-Economic Research
Programs have initiated research related
to potential health problems and the
social-economic impact of reusing waste-
water.

     Because of legislative mandates and
the need to include practical applications
of wastewater reuse in the management of
water resources, EPA has intensified its
efforts to identify research needs as a
first step in establishing a more viable
wastewater reuse program.  To implement a
multi-disciplined research effort a method
was needed for identifying research prior-
ities and providing EPA with direction for
conducting the municipal wastewater
potable reuse research program.  The work-
shop method was selected as the best
approach to defining and establishing
priorities for potable reuse research.
Ninety-two  persons concerned with waste-
water reuse, from this country and abroad,
were brought together to discuss and
identify research gaps in the areas of
health effects, treatment technology, and
the socio-economic considerations of
potable reuse.

     The Workshop was jointly sponsored
by the Environmental Protection Agency
(EPA), the Water Pollution Control Feder-
ation (WPCF), and the American Water Works
Association  (AWWA), and was held at the
University of Colorado at Boulder,
Colorado on March 17-20, 1975.

     The Workshop was three days in length
and was designed for persons involved in
the use, conduct, direction, or specifi-
cation of research in the wastewater ren-
ovation and reuse field.  WPCF and AWWA,
and selected representatives of federal,
state, municipal, industrial, academic,
and consulting organizations participated.
In addition to presentations on specific
reuse situations that included both native
and foreign experience, papers were
presented on 1) potential health hazards
of using wastewater for domestic purposes,
2) the status of existing technology that
can be used to properly treat wastewater
for reuse, and 3) the socio-economic
aspects of reuse.  The presentations
established the state-of-the-art, or
"where we are now."

     The evening of the first day and the
entire second day were devoted  to  separate
workshop groups each dealing with  one of
the following specific topics related to
potable reuse:

     ° Wastewater Treatment

     ° Treatment Reliability and Quality
          Control

     0 Health Effects Associated with
          Inorganic Pollutants

     0 Health Effects Associated with
          Organic Pollutants

     ° Health Effects Associated with
          Biological Pollutants

     0 Socio-Economic Aspects

Workshop participants were divided about
equally between these groups according to
their interest and experience.  Each Work-
shop group had a prior designated  chairman
and vice chairman to guide the group dis-
cussions and summarize the problems iden-
tified and the research needed to  solve
these problems.  The results of each
group's efforts were presented to  the
total Workshop attendees on the third day
for further discussion and multi-disci-
plinary comments.
           IDENTIFIED RESEARCH

     The research needs associated with
the potable reuse of municipal wastewater
as identified by the six individual Work-
shop groups are presented separately as
follows:

     1.  Treatment - Characterization of
the effectiveness of alternate wastewater
treatment systems for the removal  of
organics, trace metals, nitrogen,  bacteria,
viruses, parasites, and suspended  material
was considered to be the highest priority
research need.  The four treatment trains
shown in Figure 1 were identified  as
having potential for reliably producing
potable quality water from raw  (primarily
domestic) wastewater.  A need was  iden-
tified to evaluate these systems for
energy requirements, costs, by-product
production, overall reliability, and
removal of the pollutants previously
mentioned.  It was estimated that  the
intensive characterization period  would
require at least three years, plus any
further time needed for evaluation of
                                         618

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CI2
1. RAW
1
WASTE
f
LIME PRIMARY
TREATMENT
I -co2
PHYSICAL CHEMICAL
NITROGEN REMOVAL
'
1
CARBON
ADSORPTION
T
MIXED MEDIA
FILTRATION
T
CHEMICAL
OXIDATION
EFFLUENT


CI2
II. RAW
1
WASTE
PRIMARY
TREATMENT
t
AERATION BASIN
1

SECONDARY
SEDIMENTATION
If
LIME
TREATMENT
| -C02
MIXED MEDIA
FILTRATION
i
1
PHYSICAL CHEMICAL
N REMOVAL
1

CARBON
ADSORPTION
REVERSE
OSMOSIS
CHEMICAL
OXIDATION
III. RAW WASTE
*

PRIMARY
TREATMENT
*
COMBINED CARBON AND
NITROGEN REMOVAL
*
SECONDARY
SEDIMENTATION
T
LIME
TREATMENT
CH3OH *- 1 -< C02
CARBON
ADSORPTION
'
r "•* CI2
CARBON
ADSORPTION
t
MIXED MEDIA
FILTRATION
t
CHEMICAL
OXIDATION

IV. RAW
1
WASTE
f
LIME TREATMENT OR
ACTIVATED SLUDGE
1
NITRIFICATION
i

SEDIMENTATION
1 -« CH3OH
DENITRIFICATION
i

SEDIMENTATION


CARBON
ADSORPTION
*
MIXED MEDIA
FILTRATION
i
CHEMICAL
OXIDATION
VARIATIONS
(many possible)
RESIN SORPTION
FOLLOWING CARBON OR
REVERSE OSMOSIS
TWO STAGE LIME
FOR SOFTENING
ION EXCHANGE
ULTRAFILTRATION
FOLLOWING FILTRATION
DISTILLATION
INCLUDED IN EACH
EFFLUENT STORAGE
DISINFECTION
MULTIPOINT COAGULANT
^f ADDITION
CI2
KEY
CI2 = Chlorine for residual
ammonia removal
C02 = Carbon dioxide
for recarbonation
CH3OH = Methanol for
denitrification
                             EFFLUENT
                                                  EFFLUENT
                                                                      EFFLUENT
               FIGURE  1.    VARIOUS POTABLE WATER TREATMENT PROCESS  TRAINS

-------
health effects.  It was established that
each system should be demonstrated on at
least a 0.5 mgd (1890 cu.m./day) scale to
establish performance credibility, and
that the systems should be applied to
municipal wastewaters, domestic waste-
waters, and polluted river water.
     System I is an independent physical-
chemical process.  System II is a second-
ary-tertiary process.  System III is
similar to System II except that the bulk
of the nitrogen is removed in the initial
one-step biological treatment stage.
System IV is an integrated chemical-
biological treatment system.  Rough costs
were estimated to be (1975 dollars) :
$3,000,000 construction cost per system.
Analytical and operation costs (excluding
health effects) $800,000/yr. per system.

     Disinfection is a mandatory require-
ment for potable wastewater reuse to
insure protection of the public from
infection.  This requires the disinfection
process to have a high degree of control
and reliability with essentially  no
allowance for short term process failure.
Four subcategories required to better
direct the research in disinfection
include:  1) examination of the by-pro-
ducts of all disinfection processes,
2) delineation of processes that can pro-
duce safe residual levels of disinfectants,
and 3) identification of the best points
for application of disinfectants in the
treatment system.

     Present technology for organic
removal results in product waters contain-
ing 1 to 2 mg/1 of total organic carbon.
Although it has not been detemined that
there is a health hazard at this concen-
tration, a need was identified to find
processes to reduce the materials to lower
levels.  Potential methods that should be
studied are chemical oxidation; resins;
membranes; and volatile stripping.  New
methods and ideas for removing trace
organics should be solicited from appro-
priate sources.

     The identification and validation
of indicators of system performance was
identified as being necessary to permit
monitoring without developing a burden-
some analytical load.  This will be
required for reliable and cost-effective
operation.  An example of the indicators
would be the use of turbidity and  chlorine
residual measurements as indicators of
virus inactivation.

     It was concluded that nitrogen
removal will be required, but that cur-
rently available physical-chemical and
biological nitrogen removal processes will
need review because each has disadvantages.
Modifications of these processes should be
investigated to reduce their overall costs.

     Although processes are available for
removing many of the trace metals of
concern from wastewater, selenates, arse-
nates, chromates, and molybdates are not
well removed by most of the common AWT
processes.  Further study of potential
removal processes is required.  Demineral-
ization for reducing salinity is a tech-
nique that has a beneficial effect on the
removal of these ions, but the various
demineralization processes need evaluation
and improvement to reduce costs and
energy requirements.

     Two essential factors in reuse -
quantity and quality - are impacted by
storage.  Storage may occur both inplant
(recycle streams), and before or after the
renovation facility.  The main concern is
finding the least costly method of providing
the storage since the benefits of flow
equalization and product protection are
clearly evident.

     Demonstration of methods for stabili-
zation, recovery, and disposal of
residuals is needed to insure the avail-
ability of adequate and economically
viable control options for the accumulated
residuals emanating from reuse treatment
processes.  This problem area is not
unique to potable reuse, but it was iden-
tified as an important factor for eventual
implementation of specific reuse treatment
methods.

     2.  Treatment Reliability and Quality
Control - A need was identified to define
drinking water standards that can be
applied with confidence to potable waters
derived from polluted sources.  The type
of treatment systems and their reliability
requirements will depend on the standards
set for the produce water.  Fail-safe
reliability must be defined and the
factors and procedures must be established
which will assure that the product water
                                          620

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from a reuse system will be withheld from
use if all quality criteria are not met.

     The overall performance of a reuse
treatment system may be affected by:
1) the time-dependent changes in the mass
flow of some influent constitutents; 2)
the presence or absence of unknown indus-
trial constitutents; 3) the recycling of
side streams; and 4) inplant chemical
additions which may result in chemical
reaction by-products.  Therefore, infor-
mation is needed on effluent variability
and process reliability as they are
affected by influent variability, the
reliability of systems treating only
domestic wastes vs. those treating com-
bined domestic and industrial wastes, and
the effects of recycle streams.

     Some contaminants in domestic waste-
water have been or will be identified as
having an acute or chronic health effect
when present in varying concentrations
in reused wastewater.  The cost of remov-
ing these contaminants in reuse systems
will vary depending on the variability
and reliability of removal required.
Effective design and operation of reuse
systems dictates that a level of "risk"
be established that identifies the per-
missible variation in the removal
efficiency of contaminants, and balances
this with the cost of complete contaminant
removal.

     Once specific reuse systems are
chosen, they should be evaluated to
determine if there is a need for new types
of equipment not now available.  The
needed reliability of such equipment
should be determined and design specifi-
cations developed.  As new products or
equipment become available, their impact
on potable reuse systems should be
assessed and the information disseminated
to the water industry.  The rapid expan-
sion of technology will bring new
pollutants into the domestic and indus-
trial wastewater streams that require
continual updating of removal technology.

     The key to product quality control
in a reuse system lies in the availability
of suitable monitoring systems.  It is
imperative that a few specific indicator
parameters be identified and that auto-
mated monitoring equipment be developed
so that the parameters can be correlated
with the contaminants that may be health
hazards.
     Potable reuse systems are likely to
be very complex.  Step by step operation
and control strategies with contingency
action plans are needed in the event of
process failures.  Research is required to
determine the frequency of failure of key
pieces of equipment in various unit
processes.  Preventive maintenance pro-
cedures for both process equipment and
instrumentation are needed to extend the
life and increase the reliability of major
reuse equipment.  Increased operator
capability and effective management are
necessary to efficiently and reliably
operate the complex treatment systems.
Studies are needed to define the minimum
plant size that is amenable to reliable
operation, and to determine the staffing
and organizational requirements to insure
consistent operation.

     Before successful reliability design
can be achieved it is necessary to deter-
mine the allowable contaminant variability
as well as monitoring and sampling fre-
quency to insure adequate process control
for providing the reliable removal of
specific contaminants.

     3.  Health Effects/Inorganics -
Research on this topic is intimately
related to other environmental health
research, especially to that relevant to
drinking water criteria.  This research
is also related to ongoing studies on
categorical diseases such as cancer and
heart disease, and to geographical
gradients in morbidity and mortality
rates.

     There is a need to compile data on
the occurrence of inorganic materials in
water and wastewater in those geographic
areas where potable reuse is most likely
to occur first.  Multi-elemental analyt-
ical techniques such as spark source mass
spectrometry, x-ray, fluorescence emission,
and neutron activation should be used.
Research is needed to perfect sample
preparation techniques in order to
increase the sensitivity, accuracy, and
precision in monitoring.

     Organometallic compounds and metal
chelates are widely used in industry and
have a high probability of occurrence
and build-up in wastewaters.  Little is
known of their health effects, and ident-
ification is difficult.  Examples include
                                          621

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alkyl and aromatic amines, and dicar-
boxylic acid compounds that form complexes
with metal cations.

     The mere presence of an element or
compound in water need not imply that
there is any appreciable uptake.  The
material may be in an insoluble form,
complexed, or chelated.  Both animal and
human studies, along with improved physi-
cal-chemical characterization are needed
to determine the uptake fractions for
various forms of inorganic constituents
in water.  Little is known of the role of
particulate matter and its influence on
uptake.

     Populations consuming water of vary-
ing qualities should be examined from an
epidemiological standpoint to determine
whether specific contaminants represent
a potential health effect.  Body burden
estimates can be based on medical research
from samples of scalp hair, nails, blood,
urine, subcutaneous fat, and deciduous
teeth.  Body burden changes can be
detected more readily and much earlier
than manifest toxicity.  Hence, a greater
level of health protection is implied
than if one awaited more serious effects.
Where cities are known to have differences
in water constituents, autopsy, placental
tissue, or surgical specimens may show
that different water constituents lead to
different concentrations of these same
constituents in target organs.  It may be
possible to relate high levels of storage
to morbidity and mortality from various
causes.

     In-vitro bacterial and cell culture
systems should be used for the study of
contaminants in water as:  1) primary
toxicity screens; 2) indicator systems
for determining active fractions in
various fractionation schemes and refrac-
tionation of the active portions, and
3) systems for study of the interactions
of chemicals for toxicity including
mutagenesis and carcinogensis.

     Conventional animal toxicity studies
use relatively healthy normal animals,
yet human health effects of greatest
concern involve effects on infants,
women during pregnancy, and on those with
cardiovascular diseases.  There are no well
established relationships between results
on healthy animals and those with impair-
ment.  Accordingly, studies are needed of
selected types of animal  systems  to
obtain toxicity data relevant  to  high
risk human groups.

     Behavioral toxicology has been  shown
to be a useful test system for effects of
nitrites in rats.  It has been shown to be
a very sensitive indicator of  the effects
of certain compounds and  is probably the
only way alterations in cerebral function
by toxic agents can be approached in
animal studies.

     The amount of inorganic materials in
water does not necessarily relate to the
amount ingested, since a high proportion
of the liquid intake is from food and
beverages.  Therefore, it is necessary for
each substance and class of substances to
estimate the population dose based on
usual food, beverage, and water ingestion.

     Present epidemiological data relat-
ing death rates to components of  drinking
water, including components resulting
from indirect or covert reuse of  waste-
water, are confused and uncertain.   There
is a need to obtain information on the
chemical content of drinking water in
metropolitan areas that exhibit a wide
range of death rates.  Studies should be
made on the degree of association and
correlation between these data and the
age-sex-race-specific death and disease
rates, particularly for age groups between
35 and 74 years, for the specific areas
where available water data on sodium,
hardness, IDS, and trace metals exists.
Comparisons of areas using polluted  and
clean water sources should have priorities,
There is a need to coordinate an  epidemi-
ology assessment strategy to insure  that
kinds and amounts of pollution and
possible health reactions are measured
uniformly.  A small interdisciplinary
group with international support  could be
convened to develop and design such  a
strategy.

     A city planning overt reuse  of  waste-
water will require many different types
of data, accurately collected and analyzed,
to determine whether reuse has an adverse
effect.  Properly designed registries of
the incidence and prevalence of chronic
disease are efficient basic tools for
this purpose.  The registry should include
data for two or more years before overt
                                          622

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reuse,  and for several years after reuse,
on chronic as well as acute episodes of
disease.

     Associations of cadmium ingestion and
hypertension have been reported as well as
an association of hardness with low rates
of cardiovascular disease.  The substances
responsible for this association have not
been clearly determined.  Some of the
contaminants in reused wastewater may be
relevant  to this association.  Comparison
studies in like communities with different
degrees of covert reuse, or in communities
changing  their water supply, can assist in
resolving these questions.

     Rates of the incidence of "serious"
chronic disease vary from place to place.
Areas exhibiting marked differences in
chronic disease rates should be utilized
in determining the possible relationships
between incidence and concentration of
water constituents indigenous to each area.
Hospital  discharge reports and death
certificates can be used to document
incidence of "serious1' disease.

    4.   Health Effects/Organics - Many
existing water supplies contain appreci-
able quantities of organic compounds.
These compounds may present a health
hazard if they are carried into potable
water supplies.  Efforts are underway to
evaluate  the toxicity of organic compounds
in water  supplies where various degrees of
covert reuse occur.  There is a need to
carry out short-term toxicological studies
on actual wastewater effluents (and con-
centrates of them) produced by advanced
waste treatment facilities designed for
overt potable reuse.  Appropriate standard
techniques for concentrating refractory
organics  that maintain the integrity of
the chemical components are a prerequisite
for these studies.  Only chemicals iden-
tified from highly toxic fractions and
suspected of being chronically toxic
should  be subjected to longer term testing.
These long term tests should include con-
sideration of the synergistic potential.
     The  practice of disinfection of water
for biological safety has brought with it
the creation of many new and potentially
toxic chemicals.  Attention must be paid
to the  reaction products resulting from
the different means of water disinfection,
such as the use of ozone, chlorine, and
UV light.  Residual compounds such as
epoxides, aldehydes, and acids need
careful assessment.

     Research on analytical methodology
designed to identify specific organic
pollutants, some of which are hazardous
to health, should be coordinated with
ongoing work in program areas of municipal
wastewater, industrial wastes, and drink-
ing water research.  Techniques of
isolation, concentration, identification,
and quantification of organics should be
improved.  Quantitative recovery methods
that do not allow introduction of arti-
facts as well as more studies on the
identification of nonvolatile, higher
molecular weight compounds are required.

     The recent development of in-vitro
bacterial systems serve as sensitive
indicators of a candidate compound's
carcinogenic/mutagenic potential and
should be given serious consideration as
a screening tool early in the evaluation
of the health hazards of a compound or
water concentrate.

     Utilization of short term in-vitro
mammalian procedures, such as the use of
animal or human liver tissue may provide
guidelines in the early screening evalu-
ation of organics.  The metabolism of the
organics found in reused wastewater should
be studied to determine the best possible
models for toxicity testing.

     Relatively simple and rapid gross
chemical or biological methods should be
developed that give good correlation with
the presence of compounds of health
significance.  These methods must be able
to be used for routine monitoring of
potable water supplies to give assurance
that organics in the water do not con-
stitute a hazard to health.   Analyses such
as total organic carbon (TOC), chemical
oxygen demand (COD), carbon chloroform
extract (CCE), volatile organic analyses
(VOA), mutagenic microbial assay, and
other potential gross analyses should be
compared with measured concentrations of
compounds found in water that are
determined to be potentially hazardous,
so that safe levels based on the gross
techniques can be established.

     The interaction of pollutants should
be assessed.  The importance of synergis-
tic effects of, for instance, specific
                                          623

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chlorinated hydrocarbons with alcohols
and their oxidation products (aldehydes
and ketones) in amplifying toxicity
effects requires additional study.

     In order to evaluate the potential
health hazards of reclaimed waters for
potable reuse, there is a primary need to
establish the kinds of organics which are
present and their concentrations.  Such
background information will aid in the
formulation of toxicological and other
health hazard assessment plans related to
organics in drinking water.  In addition,
these studies will be very useful in
comparing characteristics of organics in
reclaimed wastewaters with present drink-
ing water supplies.

     Epidemiologic surveys of population
groups exposed to heavily polluted surface
waters are needed.  The aim is to deter-
mine whether there are any detrimental
health effects resulting from such long
term exposure.  The studies would include
testing of the body fluids and tissues for
the accumulation of compounds of potential
toxicologic importance. The sources of
organic pollutants in water are diverse
and include municipal wastewater, airborne
wastes, industrial and agricultural
wastes, and other products of commerce.
For certain pollutants, studies should be
undertaken to evaluate the relative hazard
of these compounds in water as compared
to their hazard from other sources.

     Because of the diversified problems
involved in evaluating the health effects
of potable reuse, there is a need to
develop a viable and visible program
coordinator within EPA to assess the
potability of reused wastewater.  Also,
there is a requirement for a scientific
definition of what constitutes "potable
quality."  When this has been done, the
requirement for health effects testing of
water from both overt and covert reuse
situations will be clarified.

     An assessment of hazards to operators
of wastewater renovation and reuse
facilities should be conducted.  Besides
the hazards of exposure of workers to
chemicals related to the chlorination
process, hazards of exposure to ozone or
UV light should be considered.

     There is a need to coordinate re-
search efforts in the direction of
standardizing methods for evaluating  the
health effects of organics  in  reused
waters to be used for potable  purposes.
Coordination of research should be  under-
taken on an international level with  such
agencies as WHO and the agencies of
specific countries directly involved  in
such endeavors.  The output from the
various international programs should be
integrated and disseminated by periodic
newsletters on a regular basis to all
participants. The newsletters would
address research in progress or planned,
tabulation of specific organic compounds
identified in waters, and any toxicity
data and supporting information.

     5.  Health Effects/Biological - One
of the primary public health considera-
tions for the potable reuse of wastewater
is the prevention of communicable diseases
by virus and other pathogenic micro-
organisms.  The disinfection process is a
major means by which virus are rendered
non-infective in any reuse system.  In
order to achieve disinfection the inacti-
vating agent must reach the virus.

     Methods are needed for the determina-
tion of the extent to which kill effi-
ciency is affected by adsorption of the
organism to, or entrapment in, solids for
waters of low turbidity levels (0-1 JTU).
Procedures for detecting viruses on or in
solids and the means of exposing adsorbed
virus to the disinfectant should be
developed.  Hepatitis A virus is the major
enteric virus involved in water borne
disease outbreaks, and the development
of methods for its detection and identifi-
cation are of the highest importance.
Methods are also needed for the detection,
isolation, and assay of other viruses
which are excreted from the human enteric
tract and which are of public health
importance in renovated waters.  Infor-
mation is needed on the mechanisms of
inactivation of viruses by disinfection
and adsorption.  Knowledge of the exact
mechanisms would lead to modifications of
existing processes to improve  their
efficiency.  The fate of viruses in the
treatment system will become predictable
when disinfection and adsorption mech-
anisms are better understood.

    There is an unquestioned need for the
development of a rapid and  simple testing
method that would indicate  the presence of
viruses and other pathogenic organisms  in
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renovated waters.   A comparative methods
study and evaluation of various cell
culture systems should be undertaken with
respect to their ability to detect
viruses.  The best systems should be stan-
dardized so that a uniform method would
become available to all workers, and would
also permit a comparison of laboratory
findings between laboratories.  Research
should be supported to provide a stand-
ardization of cell systems that would
afford a reproducible method for recover-
ing a test seed of virus and for assaying
infectivity titers.

     Data are required on the occurrence,
survival, and fate of viral and bacterial
pathogens in all types of treatment plant
sludges, and on the interaction between
pathogens in the sludges and soils of
varying composition.

     There is a need to prepare a state-
of-the-art document concerned with the
removal and inactivation of microbial
pathogens by pH extremes and by chemical
coagulation processes.  Such information
is necessary for a rational approach to
the development and standardization of
optimum treatment conditions for the
removal and inactivation of microbial
pathogens.

     Information is needed on the minimal
amount of ingested virus that will produce
infection.  This information would provide
the basis for establishing viral standards
for renovated waters.

     A study should be undertaken to
determine the extent to which bacteria
that colonize activated carbon and other
solid contact systems release toxic and
pyrogenic materials.  The released toxins
and pyrogens should be identified and
their potential health hazards determined.

     There is a need to conduct in-depth
surveillance and monitoring for the
presence and concentration of viruses in
effluents from existing pilot and full-
scale wastewater reclamation plants which
employ treatment trains that are likely
to be used in future production of potable
water.  Also, data are required on the
potential public health hazard of airborne
dissemination of pathogenic bacteria and
virus.  The information would aid in the
public decisions related to plant-siting.
     6.  Socio-Economic Aspects - Attempts
to institute potable reuse have not been
frequent enough to develop a clear picture
of social reaction.  Resistance is expected
unless clearly defined standards are estab-
lished that have the support of the public
health officials at all government levels.

     A national survey, as well as local
investigations of areas of potable reuse
need and feasibility should be implemented.
This includes the identification of the
extent to which the U.S. population is
presently being supplied former wastewater
as part of their raw water supply.  A
careful analysis of the amount of waste-
water in present drinking water sources
should be useful in demonstrating the
possible degree of pollution of existing
water supplies.  Public education on cur-
rent indirect potable reuse is needed.
Methods of educating the public, most of
whom are using some wastewater in their
domestic supply, are required so that they
can be informed of this in such a way that
they will understand and accept it.

     Recycling of municipal wastewater has
the potential of impacting the quantities
available for upstream and downstream water
users.  Individual state water laws must
be interpreted, modified, or both, to
accomodate the implementation of reuse.
Identification of significant legal pre-
cedents which could constrain the imple-
mentation of such reuse is needed.

     Numerous regulatory entities exist
which may have jurisdiction over various
water-consuming activities  within a given
area.  Identification of such agencies and
delineation of their respective responsi-
bilities would alert water purveyors to
standards, regulations, and legislation
that could constrain potable reuse.   The
environmental assessment could lead to
considerable litigation if the appropriate
standards, regulations, and legislation are
not adequately addressed.

     Basic economic data are needed on the
value of a certain level of water quality
to the consumer.  That is, how much money
is the average household consumer willing
to pay for a higher level of water quality?
Planning for reuse would be significantly
advanced if data were available on the
perceived vaiue of a higher quality water
over another quality.  This is particularly
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germane to decisions to implement recy-
cling now, wait until technology is
farther advanced, or to develop more
expensive conventional supplies.

     A study should be conducted on the
effects of various methods of encourage-
ment that can be exerted by funding and
regulatory agencies on separate water
supply and wastewater treatment entities
to get them to coordinate their efforts in
water management programs that include
reuse.

     Efforts should be made to determine
and forecast the relative importance of
the types of sociological, institutional,
and economic problems that will be faced
by cities pioneering potable wastewater
reuse.  This would include a determination
under varying sets of circumstances, of
the proportion of reclaimed water the
public will accept in their domestic water
supply.  There is considerable evidence
that public attitudes currently oppose
drinking reused wastewater.  This
attitude persists despite objective
evidence that "accidental" or indirect
reuse, equal in contamination to direct
reuse, is common.  The problem faced by a
pioneering city is that public attention
by tourists, convention-goers, and other
non-residents may lead to a negative
community reaction.

     A number of cities are proceeding to
develop water reuse technology on the
assumption that potable reuse will become
feasible in another 10 to 15 years.  The
problem which could arise is that public
health concerns may not be overcome when
scheduled.  The possiblity exists that a
legal injunction may be granted, on the
request of health experts or even environ-
mental groups, which bars implementation
of the project.  For this reason, assess-
ment of the social and economic impacts
of unexpected delays in scheduled reuse
become necessary.

     History shows that as innovations
increasingly become adopted, resistance to
adoption fades.  Data is needed on the
likelihood and extent to which socio-
logical, institutional, and economic
problems faced by cities practicing
potable use of wastewater will diminish,
as more and more cities adopt this
practice.
     In view of the  fact  that  our present
drinking water supplies are  often more
economical than potable reuse  water,  it is
imperative from an economic  standpoint that
existing supplies be conserved to the
greatest extent possible  within the pre-
sent "life style" of the  community.   Due
to the "unlimited supply" attitude that
has existed, the American public has
unconsciously become very wasteful of
water.  A survey directed to a review and
compilation of the various water conser-
vation programs that have been instituted
by water agencies is needed  to disseminate
the information and  expand the practice of
conservation of resources.   This would
lead to the development of a viable and
operable water conservation  program for
use by utilities.

                SUMMARY

     It is anticipated that a  program
undertaking the research  previously des-
cribed will require  a minimum  of 10 to 15
years of intensive work to develop
sufficient information to  clearly define
meaningful standards  that  can  be applied
with confidence to potable waters  derived
from a polluted source.   These standards
will have to be based on  realistic public
health considerations and  have the support
of public health officials at  all  govern-
ment levels.

     The goals of a  direct or  overt pota-
ble reuse program are similar  to those of
the present EPA Health Effects and Water
Supply programs which have recently
identified organic materials having poten-
tial health hazards  in many of our Nation's
drinking waters.   Some of  these  supplies
contain appreciable  quantities of waste-
waters, and their use for  domestic purposes
can be classified as  an indirect  or covert
form of potable reuse.

     There was a general  consensus of the
Workshop attendees that the research
identified must be addressed by  both  water
supply and wastewater organizations.  Even
if direct reuse is not implemented, all
the same questions which have  been raised
must be answered, and the  technology  must
be developed to remove potential health
hazard constituents  present in our water
supplies.

     Any program of  the magnitude required
to alleviate the health concerns of both
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overt and covert potable reuse is not a
local or even a national undertaking.
International coordination is necessary
since other nations such as South Africa,
Israel, and some in the European community
are facing deteriorating and unreliable
water supplies, and are actively research-
ing the problems involved with covert and
overt potable reuse.

     The research identified at the
Workshop will be used to lay out a long
range approach which will utilize the
results from the ongoing EPA Wastewater,
Health Effects, and Water Supply Programs.
By clearly defining a strategy for potable
reuse the results from these programs can
be used as "stepping stones" for a future
potable reuse research program.

                REFERENCES

1.  "Water Policies for the Future,"
    National Water Commission, Washington,
    D.C., (June 1973).

2.  "Statewide Standards for the Safe
    Direct Use of Reclaimed Wastewater for
    Irrigation and Recreational Impound-
    ments," State of California Department
    of Public Health, Berkeley, CA (May
    1968).
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                            AGENDA

                       WASHINGTON,  D.  C.

                  WATERSIDE MALL - ROOM 3305

                     Tuesday,  October  28
 9:00 am    F.  Green  -  Welcome
            J.  T.  Rhett  -  Conference Opening
            Dr.  T.  Kubo  -  Response
            Dr.  W.  K.  Talley  -  Remarks,  Office of Research
                                 and Development
            R.  A.  Canham  -  Greetings from Water Pollution
                                 Control Federation
            J.  T.  Rhett  -  Introduction of Delegates and
                                 Confirmation of Agenda

 9:30 am    W.  S.  Groszyk  -  Planning for Urban Runoff Control
                                 Under a Comprehensive Water
                                 Quality Management System

10:15 am    Break

10:30 am    R.  B.  Schaffer  -  Control of Water Pollution
                                 Through Issuance of Discharge
                                 Permits - Implementation of
                                 P.L.  92-500

11:15 am    E.  P.  Hall  -  The EPA Pretreatment Program for
                                 Industrial Wastes

12:00 noon  Luncheon  -  Hosted by the Water Pollution
                                 Control Federation

 1:30 pm    C.  C.  Taylor  -  Municipal Sewer Utility Financing
                                 Under P.L. 92-500

 2:15 pm    J.  T.  Rhett  -  A Perspective on Municipal Pollution
                                 Control - The Construction Grants
                                 Program and P.L. 92-500

 3:00 pm    Break

 3:15 pm    J.  G.  Moore, Jr.  -  Commission Charge - Tentative Staff
                                 Issues and Findings National Commission
                                 on Water Quality

 4:00 pm    J.  T.  Rhett  -  Closing and Announcements
                                628

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                  PLANNING FOR URBAN RUNOFF CONTROL UNDER COMPREHENSIVE
                              WATER QUALITY MANAGEMENT SYSTEM

                                     Walter S.  Groszyk
                         Deputy Director,  Water Planning Division
                              Environmental Protection Agency
                               East Tower, Room 815 - WH-554
                                    401 M Street,  S.W.
                                  Washington, D.C.  20460
                                         ABSTRACT
                                                                               I
     This  paper summarizes the approach being developed by the U.  S.  Environmental
Protection Agency for the abatement of urban storm runoff.  The approach features the
development,  at the local or regional level, of specific management practices to
control runoff.   These practices emphasize non-capital intensive methods of minimizing
the pollutant loading of runoff and are formulated through a comprehensive areawide
planning effort that assesses the dimensions of the runoff problem, the water quality
effects, and  abatement needs.

                                           TEXT
     The United States Environmental Pro-
tection Agency through the States and
cities conducted a survey of the estimated
construction costs to abate storm sewer
pollution.   This survey of needs amounted
to nearly $250 billion in current dollars.
While the number does not generally reflect
any engineering plans or detailed surveys,
its rough magnitude is staggering and
beyond the digestive capacity of the Fed-
eral budget.  There is simply no foreseeable
way that the Federal Government would be
able to finance a construction program of
this size for this problem.  It exceeds by
tenfold the total program of landing a man
on the moon, and is nearly ten times the
total annual contract construction value in
the U.S. gross national product for 1973.
As an additional perspective, the estimated
costs, in this same Needs Survey, for con-
structing treatment plants, interceptor and
collection sewers, and controlling combined
sewers totalled approximately $100 billion,
with the total need becoming nearly $350
billion.

Areawide Planning

     Under the Federal Water Pollution Con-
trol Act, an areawide planning program is
to be conducted in urban-industrial areas
with significant water quality problems.
This planning program has just begun, and
at the present time planning is under way in
149 areas at a cost of $163 million.  This
planning covers many of the largest cities
of the United States, including New York,
Philadelphia, Chicago, and Detroit.  These
plans will eventually cover the entire
United States.  Presently, about 45% of
the population and 11% of the land area
of the United States are covered by area-
wide planning.

     Areawide planning is also called 208
planning, after the number of the section
of the Federal Water Pollution Control Act
which authorizes it.  Areawide planning is
quite unique for three reasons.  It is
expected to be the largest planning pro-
gram ever funded by the Federal Government;
all the financing for the program comes
from the Federal Government; and the law
requires that the plans be implemented.

     Areawide planning conducted for a local
area is a comprehensive plan.  The plan
covers both point and nonpoint sources of
pollution.  It includes:  initial  facilities
planning for municipal sewage  treatment
works; an identification of industrial, pol-
lution control requirements; and the
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identification of practicable methods and
procedures for the control of nonpoint
sources of pollution, including runoff from
agricultural, silvicultural, mining, and
construction activities.

     The planning effort is conducted at
the city and county level, and is under the
direction of the chief elected officials of
local government within the planning area.
This will assure that plan development
reflects the views of the government
officials who will operationally implement
the plan.  The initial plan is to be comp-
leted not later than three years after the
planning agency has been approved by EPA.
At the time of completion, EPA is required
to approve the designation of the manage-
ment agencies who will carry out the plan.
The planning agency continues to function
and develops revisions to the plan as they
are required.

     This stress on locally originated
planning conducted under the direction of
locally elected officials reflects an
appreciation that levels of abatement more
stringent than those required by nationally
applicable effluent guidelines for industry
or uniform secondary treatment for munici-
palities can often best be addressed by
examining the specific pollution problems
in that area which remain after national
levels of control are applied; assessing
the institutional and financial capabili-
ties that exist or can be developed to
abate the sources of this remaining pollu-
tion; and then making the tradeoff's
between alternative control methods to
develop the most effective and reasonable
way of reaching the water quality
objectives.

Best Management Practices (BMP's)

     The Environmental Protection Agency,
to assist planning agencies in making these
tradeoff's, is developing informational
guidelines outlining different methods and
procedures that can be used to abate non-
point source pollution including urban
runoff.  These informational guidelines are
called Best Management Practices or BMP's.
A BMP is not an "end of the pipe" techno-
logical control level, but rather is a way
of doing business.  It is directed to the
activity being conducted; as an example, it
may indicate that sediment runoff from a
farmer's field can be reduced by changing
the manner in which the farmer plows the
field.  BMP's are being  developed  for all
categories of nonpoint source  pollution,
including urban runoff.

     BMP's for a particular  category
present an array of alternative  practices
with varying economic costs  and  efficiency
rates.  The practices often  identify  cli-
matological or topographical suitability.
From this inventory of BMP's we  expect  the
planning agencies to select  those  practices
which most fit the abatement needs of  their
area.  The planning agency is  not  required
to use any of the BMP's  but  may  develop an
equivalent BMP on its own.   While  Best
Management Practices are generally con-
cerned with non-capital  intensive  methods
of control, they are not exclusively  so.
A planning agency may also,  after  analysis,
determine that the most  effective  and
economic way to achieve  water  quality goals
for that area is through the construction
of facilities and structures.

BMP's and Urban Runoff

     Our present perception  is that it is
neither necessary nor possible to  treat all
storm waters.  A receiving water is subject
to stresses caused in part by various
natural and uncontrollable occurrences.
Many streams experience  difficulty during
the low flow and high temperature  period
of later summer.   Wet weather  conditions
represent yet another period of  stress.

     The true extent of  the  storm water
problem is largely unknown and the lack of
any extensive historical studies or con-
cern makes it difficult  to characterize.

     Considering the area and route that
urban runoff takes,  it is not surprising
that this runoff contains substantial
amounts of organic material, inorganic
material, inorganic solids,  nutrients,
heavy metals and micro-organisms.  The
impacts from this runoff are often
increased oxygen demand, high  turbidity,
and increased eutrophication rates.  Addi-
tionally, the impact of  heavy metals on the
aquatic environment has  to be  considered.

     The total pollutant load  in storm-
water,  during storm runoff periods, can be
greater than the pollutant load  discharged
from municipal treatment plants  during dry
weather.  This could preclude meeting water
quality standards regardless of  the degrees
or types of treatment afforded dry weather
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wastewater  flows.

     Related problems  resulting from
unregulated, or poorly regulated,  runoff
are accelerated erosion of  land area and
stream banks,  sedimentation of  channels,
increased flooding,  increased potential for
public health  problems and  deterioration of
aesthetic quality.

     Assessing the impact of stormwater run-
off is not  easy.  Part of the difficulty
lies in  the variability of  stormwater run-
off.  The quantity and quality  of  storm
overflows,  for example,  can vary with
respect  to  storm characteristics,  antecedent
conditions, time, location,  degree of urban-
ization  and other factors.   This variability,
the differing  problems in new and  expanding
urban areas compared with existing areas,
and the  scarcity of  information concerning
stormwater  impact on receiving  waters pose
challenges  to  the formulation and  admin-
istration of an effective management program.

     Some of the examples of these varying
factors  are that:  loading  rates are lowest
in commerical  areas; BOD 5 and COD  concentra-
tions are lowest in  residential and heavy
industrial  areas, while  the  COD concentra-
tion is  highest in commerical areas;  cadmium
concentrations are relatively uniform across
all areas;  chromium, nickel, and copper are
lowest in residential  areas, with  lead con-
centrations lowest in  heavy  industry areas;
and finally, and surprisingly,  there is no
significant difference between  land use
category and fecal coliform  count.

     From the analysis of the specific  prob-
lem parameters with  respect  to  water quality
and with a  correlation as to the likely land
use areas and the sources of the problem,
the planning agency  can then analyze which
BMP's it might apply to control  the problem.

     BMP's within an urban/suburban area
include source regulation, collection  system
control,  treatment,  and an integrated
approach using all three.  Source  control is
defined as those measures for preventing or
reducing stormwater pollution that  utilize
management techniques  (e.g., good house-
keeping methods)  and stormwater  detention
within the urban drainage basin  before
runoff enters  the sewerage system.
Collection system control includes  all
alternatives pertaining to collection
system management,  such as use  of  sewers as
detention facilities.  Treatment, including
storage, is another technique.  The  term
storage refers to stormwater being retained
for the purpose of treatment as opposed to
storage used in source control to attenuate
the rate of runoff.  Flow attenuation is
concerned directly with runoff as it moves
over the surface of the urban area;  i.e.,
the initial collection system.  Flow attenu-
ation, in an hydrologic sense, means to
increase the time of concentration and
decrease the magnitude of the peak runoff.
In terms of water quality this means that
runoff velocities are reduced and less pol-
lutants are entrained.  Also, less erosion
results because reduced runoff velocity
reduces the erosion force.  Moreover, large
volumes of water are not allowed to rapidly
accumulate at constrictions, but flow at
reduced rates over a longer period of time,
thus reducing the possibility of localized
flooding. An integrated approach might
include source control to help reduce pol-
lutant loads and runoff rates; collection
system control (sewerage) to reduce infil-
tration and to attenuate the runoff; and
treatment as a final stop where required
to meet water quality objectives.

     The management goals become:

     1.  Prevention and/or reduction of
         pollution.

     2.  Detention or retention of runoff.

     3.  Treatment of runoff.

     An additional goal that should not be
overlooked is reuse of stormwater runoff.
Reuse of stormwater places urban runoff in
the resources category.  It should be con-
sidered in those areas that can benefit from
groundwater recharge and supplemental sup-
plies for both potable and nonpotable use.

     The goal of the planning approach is
to provide sufficient pollutant reduction
to meet water quality objectives at a
minimum cost.  BMP's for urban runoff
should stress source and collection system
management, and reuse where applicable.
Treatment should be resorted to only when
all other lower cost methods have failed to
provide sufficient pollutant reduction.

     Urban runoff management should
initially emphasize the new urban areas.
These new areas include land that is in the
process of becoming urbanized.  These are
areas that allow for the greatest degree of
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flexibility of approach in addressing the
long-term problems.  At a minimum, urban
runoff pollution must be contained to pre-
sent problems.  Once contained, then
emphasis can shift to problems associated
with existing areas.  Of course, for this
approach to be effective, complete area
coverage is required and the approach
should be implemented as appropriate
throughout the entire planning area.

     For a BMP to be considered as a best
management practice, it must meet certain
general and specific criteria.  Factors
that need to be addressed within a BMP
include, but are not limited to, the
following.

     A BMP must be compatible with the
hydrology and meteorology of the planning
area.  The frequency, intensity, duration,
and surface area extent of precipitation
must be addressed; also, infiltration
rates, depression storage, and runoff
rates.  Groundwater must be considered in
relation to recharge areas and levels, and
effect on stream channels fed from ground-
water.

     Runoff from snowmelt in some areas of
the country (for example, in parts of the
West) produces the major portion of the
annual runoff.  An important factor in
considering snowmelt is the temperature.
Other factors to be addressed are wind and
humidity.

     Topography, of course, is a factor
that must be considered.  A BMP must be
compatible with the slope, length of basin,
and type of surface cover of the planning
areas.

     Geology is another factor to be
addressed.  Soil types vary widely across
the country.  A BMP must consider and be
compatible with this variable.

     The specific examples of BMP's that
can be examined are to be considered as
being site-specific and are not to be con-
strued as being applicable nationwide.

     Source Control

     Some examples of source control are:

     1.  Street sweeping or control
         through housekeeping.
      2.   Sewer  flushing to reduce first
          flush  effects.
      3.   Detention basins.

      4.   Rooftop  storage and parking
          lot  storage.

      5.   Porous paving,  to  increase
          infiltration.
      Collection  System  Control

      Some  examples  of collection  system
control are:

      1.  Use of  existing  sewerage as
         detention  facilities.

      2.  Use of  swirl concentrators.
     Treatment

     Two examples which have been studied
and have been found feasible for storm-
water treatment are:

     1.  Micro-straining with air
         floatation.

     2.  Contact stabilization.

     Institutionally, we expect the
planning process will work in the follow-
ing manner.

     The planning agency staff will assess
the magnitude and extent of the urban pol-
lution problems.  These will be presented
to the public and any advisory groups to
ensure that a basic understanding of the
problems is shared by all.

     The staff will then formulate water
quality goals based on protecting bene-
ficial uses of water.  These will be
discussed with the public and will be
presented to the advisory committee.  The
advisory committee overseeing the develop-
ment of the plan will select the approach
which best meets the goals.

     Proposed criteria for controlling
urban runoff pollution will be prepared
by the staff in consultation with the
public.  An inventory of alternative BMP's
which meet the proposed criteria will be
made.
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     The staff will evaluate and make
initial selection of those BMP's which
meet the water quality objectives, and the
public and advisory group will decide which
of the BMP's are institutionally and
economically acceptable.  Final selection
of the BMP's will be made then by the staff.

     After the urban runoff problem has
been assessed, runoff reductions to help
meet target load allocations achieved by
the use of BMP's often need to be trans-
lated into ordinances or regulations.

     Within EPA, we believe the use of the
areawide planning process together with the
systematized assessment of BMP's offers an
attractive alternative to total reliance
on capital facilities for control of urban
runoff.  The planning process has just
begun, and we would like to report at a
future conference on the results from this
effort.
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                        CONTROL  OF  WATER POLLUTION THROUGH ISSUANCE OF
                       DISCHARGE PERMITS,  IMPLEMENTATION OF P.L.  92-500

                                        R.  B,  Schaffer
                                 Director,  Permits Division
                                     Office of  Enforcement
                             U.S. Environmental Protection Agency
                                   Washington,  D.  C.  20460
       OBJECTIVES OF THE NPDES PROGRAM
     On October 18, 1972, the Amendments to
the Federal Water Pollution Control Act es-
tablished the National Pollutant Discharge
Elimination System (NPDES).  With the enact-
ment of this new legislation Congress has
stated that it is the National goal that
the discharge of pollutants into navigable
waters be eliminated by 1985.  As an interim
goal it is stated that there be attained by
July 1, 1983, water quality which provides
for the production and propagation of fish,
shellfish and wildlife and provides for the
recreation in and on the water.

     Any permit issued under the National
Permit System will impose on a discharger
of pollutants from a point source certain
requirements designed to attain the goals
of the Act.  Every discharger must make
application for a permit and in so doing,
provide the permitting authority with data
on the discharge.  Each issued permit will
meet effluent limitations, water quality
standards, new source performance standards
for new plants, and toxic pollutant stand-
ards.  Facilities discharging into a muni-
cipal waste treatment facility do not re-
quire a discharge permit, but the discharger
must comply with pretreatment standards
promulgated under the Act.  Permits will
require the discharger to monitor the dis-
charge, to keep records of monitoring ac-
tivities and report periodically on what is
occurring with regard to the discharge.

        THE EFFLUENT LIMITATIONS
     The new Act provides for uniform ef-
fluent limitations for industrial categories
and achievement dates.  Congress set two
interim dates of July 1, 1977 and July 1,
1983, by which different levels of treat-
ment are to be reached.  It is a timetable
based on advances in technology.
     For all discharges other than publicly
owned treatment works, not later than July 1,
1977, effluent limitations are to be achieved
which represent the application of the "Best
Practicable Control Technology Currently
Available."  At the same time, all publicly
owned waste treatment facilities must uti-
lize "secondary treatment" and, if an indus-
trial discharger sends its waste through a
publicly owned treatment works, certain "pre-
treatment standards" must be met.  An addi-
tional requirement is that by the July 1977
date, effluent limitations may be imposed so
that any state law will be met.  Not later
than July 1, 1983, effluent requirements
must be met which represent the "Best Avail-
able Technology Economically Achieveable"
and, for publicly owned waste treatment
facilities, which represent the application
of the "Best Practicable Waste Treatment
Technology/'  Any other applicable pretreat-
ment standards must also be attained by that
date.  Special standards of toxic substances
must also be observed for both the 1977 and
1983 targets.

     The target dates are 1977 and 1983;
they are the outside limits for compliance.
The Act envisions that in meeting effluent
limitations there will be stages of compli-
ance including attainment of levels of sub-
stantial improvement even before these dates.
Therefore, most permits will impose a
schedule of remedial measures.  This sche-
dule will appear as a condition set out in
an NPDES permit.

     The Agency has requested authority to
extend the 1977 date on a case-by-case basis
for publicly owned treatment works.  However,
we do not feel it is necessary  to extend  the
date for other dischargers nor do we expect
the National Commission on Water Quality  to
recommend it to Congress.
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    BEST  PRACTICABLE CONTROL TECHNOLOGY
       AND  BEST AVAILABLE TECHNOLOGY
      The  Act  charges the Administrator with
 the task  for  publishing regulations provid-
 ing "Guidelines" for effluent limitations
 for point sources after he has consulted
 with the  appropriate Federal and State
 agencies  and  other interested persons. These
 effluent  limitations are the ones which
 shall require the application of the Best
 Practicable Technology by 1977, and Best
 Available Technology Economically Achieve-
 able for  the  1983 target dates.  Two things
 will be identified in the regulations.

      First, they will give meaning to the
 terms "Best Practicable" and "Best Avail-
 able" when applied to various categories
 of industries.   In defining "Best Practic-
 able" and "Best Available" for a particular
 category, such factors as the age of the
 equipment and facilities involved, the pro-
 cess employed,  the engineering aspects of
 the application of control techniques, pro-
 cess changes, and non-water quality environ-
 mental impact (including energy require-
 ments) will be taken into account.  In
 assessing "Best Practicable Control, a
 balancing test between total cost and ef-
 fluent reduction benefits is to be made.
 Cost is also  a factor in determining "Best
 Available."  "Best Available" technology is
 the highest degree of technology that has
 been demonstrated as capable of being de-
 signed for plant scale operation, so that
 costs for this treatment may be much higher
 than for treatment by "Best Practicable"
 technology.  Yet economic feasibility will
 also be a factor in interpreting "Best
 Available" treatment.  Cost effectiveness
 for either standard is to be confined to
 consideration of classes or categories of
 point sources and will not be applied to
 an individual point source within a cate-
 gory or class.

     Second, having interpreted "Best Prac-
ticable" and "Best Available" guidelines
will be published which will determine what
"Effluent  Limitations" are to be imposed on
dischargers.  In these guidelines the degree
of  effluent reduction attainable through the
application of the "Best Practicable Control"
and "Best  Available Technology" in terms of
amounts of constituents per unit of produc-
tion.   These guidelines can then be applied
in  setting specific effluent limitations on
dischargers.
     The Agency will promulgate these various
standards and guidelines for some 200 classes
and categories of dischargers.

   TOXIC POLLUTANT EFFLUENT STANDARDS
     The Act requires the establishment of
effluent standards or prohibitions controll-
ing toxic pollutants.  Toxic pollutants are
defined as those pollutants, or combinations
of pollutants which, after discharge and
upon exposure to any organism either directly
or indirectly, will "on the basis of infor-
mation "available" cause death, disease, or
other abnormalities in the organism or its
offspring.  The drafters of the Act had in
mine certain substances such as mercury,
beryllium, arsenic, cadmium pesticides, etc.

     A list of toxic pollutants has been
proposed.  Effluent standards for those
toxic pollutants listed will be published
later.

    NEW SOURCE PERFORMANCE STANDARDS

     Most new plants will be subject to
national standards for performance.  EPA is
to publish a list of categories of sources
which must include 27 major types of indus-
tries and then issue regulations establish-
ing Federal standards of performance for
the new sources within such categories.
These standards are to assure that new sta-
tionary sources of water pollution are de-
signed, built, equipped, and operated to
minimize the discharge of pollutants.  The
standards are to reflect the greatest degree
of effluent reduction which the Administra-
tor determines to be achievable through
application of the best available demon-
strated control technology, processes,
operating methods, or other alternatives.
"Best Available Demonstrated Technology" has
been described as those plant processes and
control technologies which, at the pilot
plant or semiworks level, have demonstrated
that both technologically and economically
they justify use in new production facili-
ties.

     At the same time EPA promulgates new
performance standards, it is to provide
pretreatment standards for newly constructed
point sources discharging into public treat-
ment facilities.
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         WATER QUALITY STANDARDS

     The new Act does not ignore the concept
of water quality standards in 19.77 and 1983
achievements.  Water quality standards which
were adopted and enforced under the old
Federal Water Pollution Control Act (FWPCA)
for interstate waters are continued in effect
and can be updated and the new ones are to
be established for intrastate water bodies
where not previously adopted by the States,
If water quality standards cannot be pro-
tected by the application of best practic-
able control technology for industries and
secondary treatment for municipal wastes
before 1977, then more stringent effluent
limitations are to be imposed which will
pro-tect water quality for public water
supplies, agricultural and industrial uses,
assure protection of a population of fish
and wildlife, and allow recreational activi-
ties.

          EFFLUENT LIMITATIONS

     The permit will contain one or more
sets of numerical limitations which must be
met by a date specified in an associated
compliance schedule.  In general, the ef-
fluent limitations, with the exception of
pH, will be expressed in terms of total
weight (Ibs/day or kg/day).  The effluent
limitations in the permit are described in
terms of daily average and daily maximum
values.  The limitations expressed in the
permit are based on promulgated effluent
guidelines, interim guidance or water
quality standards if more stringent limits
are necessary to protect water quality. The
limitations or standards established by the
Agency are to be applied in a uniform manner
throughout the country.  The standards are
minimum technological requirements to be
applied even though the receiving water may
not require that level of abatement to
achieve the desired water quality.

           COMPLIANCE SCHEDULE

     The compliance schedule will specify
when final effluent limits must be attained
and may also contain dates for achieving
certain plateaus such as development of
engineering reports, final plans, beginning
of construction, completion of construction
and the operation of facilities.  Interim
dates and requirements are to be specified
in the permit as a means of monitoring
progress and minimizing slippage.  Following
each interim date, the permitee must submit
 a written  notice of  compliance or non-com-
 pliance  with  the interim requirements.  The
 reports  specified in the permit are very
 important  and  should be  submitted on time.
 Failure  to report, especially  on construc-
 tion progress  or compliance, will result  in
 response from  the Agency.

        MONITORING AND REPORTING

     The self-monitoring  requirements con-
 tained in the  permit will be developed on an
 individual basis  with consideration  given for
 the type of treatment, the impact  of the pro-
 posed treatment  facility  on the  receiving
 water and the  parameter  to be measured.  The
 purpose of the monitoring program  is to
 establish that a  treatment facility  is con-
 sistently meeting the effluent limitations
 imposed in the permit.  Data must  be recorded
 and retained on  file by the permittee for at
 least three years.   The reporting  frequency
 of monitoring  results will be specified in
 the permit.  A uniform reporting  form has
 been developed and will be provided  to the
 permittee.   The  self-monitoring may vary
 from State to  State  as individual  conditions
 are developed  to  insure compliance with
 State r equir ement s.

     The permits  are issued for  fixed terms.
 The maximum duration of a permit will be
 five years.  The majority of permits have
 been written for  that period since it will
 involve commitment to a long term  abatement
 program.  Permits may be written  for a
 shorter period, however, e.g., the State
may require it or the facility may cease
 operation.

           STATE  CERTIFICATION

     After drafting, a permit is  forwarded
 to the appropriate States for certification.
 The State has  the right to add additional
 requirements in monitoring, compliance, and
 additional or more stringent effluent limit-
 ations.  The Agency, upon receipt  of certi-
 fication requirements, will place  these in
 the permit.  Any  challenge to any  State
 certification  requirements must  be through
 State  administrative procedures.
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STATUS OF THE PROGRAM AS OF JUNE 30, 1975

     EPA and 24 States which were delegated
the authority to issue NPDES permits had,
as of June 30, 1975, issued 20,091 Indus-
trial permits; 16,664 Municipal permits;
1,548 Agricultural permits; and 1,988 Fede-
ral Facility permits making a total of
40,291 permits issued.  Approximately 1600
EPA issued permits have been challenged
through Administrative Processes.  Of these,
400 have been resolved through discussions
between interested parties, e.g., govern-
ment, industry, and public interest groups.
We expect very few appeals to proceed
through this process and into our courts.

     A study to determine the total amount
of certain pollutants that will be removed
from our Nation's waters due to the imple-
mentation of P.L. 92-500 and the industrial
portion of the permit program resulted  in
an estimated reduction of approximately  12
million pounds per day of BOD and 28 million
pounds per day of suspended solids.

     The continuation of our effort will
now shift into compliance monitoring to
assure that the terms and conditions of  the
permits are met and the goals of the Act
achieved.
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                  THE EPA PRETREAIMENT PROGRAM FOR INDUSTRIAL WASTES
                                      Ernst P. Hall
                                        U.S.E.P.A.
                   401  M Street, S.W.,(WH5b2) Washington, DC
               20460
                                        ABSTRACT
    The Federal  Water Pollution Control  Act Amendments of 1972 (PL 92-500) directs the
promulgation of Federal  standards for pretreatment of industrial  waste waters which are
introaucted into a publicly owned treatment works.  These standards will require pretreat-
ment to control  pollutants which would interfere with a pass through a treatment works.
Enforcement will be primarily at the local  level with a Federal overview and presence.
    Pretreatment  of   industrial    wastes
before   introduction   into  a  publicaly
treatment works (POTW) has been  discussed
by  Mr.  Sutfin  at  the second U.S./Japan
Conference.  Since that presentation there
have been a number of refinements   in  our
thinking  and  approach  to  pretreatment.
This paper reflects the present status  of
these refinements.
    The  Federal  Water  Pollution Control
Act Amendments of 1972, were  designed  by
Congress to achieve an important objective
   to  "restore and maintain the chemical,
physical, and biological integrity of  the
Nation's  waters."  Primary  emphasis  for
attainment of this  goal  is  placed  upon
technology  based  regulations.   Existing
industrial point sources  which  discharge
into   navigable   waters   must   achieve
limitations  based  on  Best   Practicable
Control   Technology  Currently  Available
(BPT) by July 1, 1977 and  Best  Available
Technology  Economically  Achievable (BAT)
by  July  1,  1983  in   accordance   with
sections  301(b)  and 304(b).  New sources
must comply with  New  Source  Performance
Standards  (NSP)  based  on Best Available
Demonstrated  Control   Technology   (BDT)
under   section   306.    Publicly   owned
treatment   works   (POTW)    must    meet
"secondary  treatment"  by  1977  and best
practicable waste treatment technology  by
1983  in  accordance with sections 301(b),
304(d) and 201 (gj(2)(A).  Users of a POTW
also fall within the statutory  scheme  as
set  out  in section 301(b).  Such sources
must comply  with  pretreatment  standards
promulgated pursuant to section 307.
    Limitations  and  standards applicable
to direct dischargers are established  for
categories   and  subcategories  of  point
sources.   This  same  categorization   is
applied  to  pretreatment and pretreatment
standards, generaly, will
for   each   category  or
industrial  point  source
general    pretreatment
existing sources (40 CFR
  be  established
  subcategory  of
  discharge.     A
 regulation   for
128) was  adopted
some  two  years ago and is now undergoing
revision,  ihe revised regulation   (40  CFR
4u3)  is  expected to provide a regulatory
basis for both existing and new sources.
    The  term  "pretreatment"  means   the
application   of  physical,  chemical  and
biological processes to reduce the  amount
of  pollutants  in  or alter the nature of
the pollutant properties in a waste  water
prior to discharging such waste water into
a  publicly  owned  treatment  works.   Ihe
basic  purpose  of  pretreatment   is    "to
prevent  the  discharge  of  any pollutant
through   treatment   works...which    are
publicly owned, which pollutant interferes
with,  passes  through,  or  otherwise  is
incompatible with such works." The  intent
is  to  require  treatment at the  point of
discharge complementary to  the  treatment
performed  by  the  POTW.   Duplication of
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treatment  is  not the goal.  Pretreatment
of pollutants which are not susceptible to
treatment in a POTW is absolutely critical
to the attainment of the overall objective
of the Act, both by  protecting  the  POTW
from  process upset or other interference,
and by preventing discharge of  pollutants
which  would  pass through or otherwise be
incompatible with such works.
    Pretreatment  standards  should  allow
the  maximum utilization of a POTW for the
treatment of industrial  pollutants  while
preventing  the  misuse of such works as a
pass-through device.  The  standards  also
should  protect  the  aquatic  environment
from discharges of inadequately treated or
otherwise undesirable materials.
    The  primary  technical  strategy  for
establishing     pretreatment    standards
consists of the  following  provisos:  (1)
pretreatment    standards   should   allow
materials to be  discharged  into  a  POiW
when  such  materials  are similar, in all
material  respects,  to  municipal  sewage
which  a "normal type" POTW is designed to
treat; (2) pretreatment  standards  should
prevent the discharge of materials of such
nature   and   quantity,   including  slug
discharges, that they  would  mechanically
or   hydraulically   impede   the   proper
functioning of a  POiW;  (3)  pretreatment
standards  should  limit  the discharge of
materials   which,   when   released    in
substantial   concentrations  or  amounts,
reduce the biological effectiveness of the
POTW or achievement  ot  the  POTW  design
performance,  but  which  are treated wnen
released in small or  manageable  amounts;
and   (4)  pretreatment  standards  should
require  the  removal,   to   the   limits
dictated by technology, of other materials
which  would  pass through -- untreated or
inadequately treated --  or  otherwise  be
incompatible with a normal type POTW.
    In  addition  to  these  provisos,  it
appears to be  administratively  necessary
and  technically  desirable to establish a
volume cutoff or limit  below  which  most
materials  may  be discharged into a POTW,
while requiring pretreatment standards for
larger flows and more hazardous materials.
This is intended  to  be  accomplished  by
defining,   for   the   purpose   of   the
regulation, a major contributing  industry
is  a discharger who either (a) has a flow
of 50,000 gallons per day, or  (b)  has  a
flow  equal  to  or greater than 5% of the
capacity  of  the  POiW.   Any  discharger
meeting either of these requirements would
be  subject  to all pretreatment standards
while a discharger  not  classified  as  a
major   contributing   industry   by  this
criteria  may  not  be  required  to  meet
specific numerical pretreatment standards.
The  specific  determination is to be made
in each subpart and  for  some  particular
subparts  it  may be desirable to alter or
change the definition of a  major  contri-
buting  industry in order more properly to
apply pretreatment standards, particularly
where use of the volume cut-off would  not
provide   adequate   protection   to   the
environment.
    The first  proviso  is  clear  in  its
application  and  materials  meeting  this
proviso should be allowed to be introduced
into a POTW without  pretreatment.   uther
applications  ot  these  provisos  will oe
discussed in the following paragraphs.
    I he control of influent pH is  usually
adjusted   adequately,   particularly  for
mildly acid wastes, by the alkalinity  and
buffering  capacity  of  normal  municipal
waste waters.  Additionally, if necessary,
treatment   of   pH   can    readily    be
accomplished  by  chemical  addition  in a
POTW.     However,   highly   acid   wastes
characterized  by  materials  having  a pH
below  five  have   the   capability   for
destroying  the  sewer  pipes  and  sewaae
treatment facility itself because of their
ability  to  attack  metal,  concrete  and
mortar  joints.   One particularly adverse
reaction from the corrosion of acid wastes
is to destroy the integrety of in concrete
sewers, thereby allowing the  infiltration
of  water during a rainy season.  For this
reason, very low pH wastes -- below  a  pH
of  5.0  --  are  included  as  prohibited
wastes  even  though   pH   is   generally
considered  to  be adequately treated in a
POTW.
    Heat  is  defined  in  the  Act  as  a
pollutant.   In most cases, heat in fairly
substantial quantities can  be  discharged
into  a municipal sewage system along with
waste water without causing  an  upset  or
other  difficulty  in  operating the POTW.
As  a   matter   of   fact,   some   heat,
particularly in cold weather, may prove to
be  beneficial,  and  may  accelerate  the
effectiveness of  the  treatment  process.
However,    the   normal   POTW   includes
biological   treatment    systems    whose
performance  can  be affected adversely if
an  excess  of  heat  is  found   in   tne
treatment  plant  itself.   This  point of
damage to biological activity is generally
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 considered to  be  40%C  (I04%F).   Hence,
some  safeguard  is  needed  to prevent an
excess of heat  being  discharged  to  the
treatment   plant   while  still  allowing
lesser amounts of heat to be discharged to
and dissipated in a POTW.
     Slug discharges which cause  an  upset
in  the treatment process and a subsequent
loss  of   treatment   effectiveness   are
undesirable  both  for  environmental  and
treatment   plant   operational   reasons.
Defining  a  slug  discharge in quantative
terms  is  difficult.   It'   is   commonly
recognized  that  the  peak  two hour flow
rate of normal municipal sewage  is  about
two  times  the ratio of the average daily
flow.  This ratio holds for both hydraulic
loading  and  for  oxygen   demand   (BOD)
loading.   In order to establish a readily
definable  discharge  level  at  which  an
industrial  user  may  become  liable  for
causing a POTW upset, a slug discharge  is
defined  based  on  the  normal maximum to
average ratio.   However,  the  prohibited
waste   section  does  not  prohibit  slug
discharges per se but only prohibits  slug
discharges which cause a POTW upset.
     Some materials are known to be treated
effectively  in  small concentrations in a
POTW  but  are  not  treated   effectively
whenever  the  amount  of  such  materials
exceeds  the  system's  tolerance   levels.
Regulation of these types of materials can
effectively  allow  the  POTW  to treat as
much of the  pollutant  as  it  reasonably
can,  while  preventing  an excess of such
material from passing through untreated or
reducing the  treatment  effectiveness  of
the  PuTW.   One  such  material currently
under review by  the  Agency  is  oil  and
grease of a mineral origin.  The Agency is
considering    establishing    a   general
limitation  setting   forth   a   specific
concentration  as  a pretreatment standard
for  this  particular  parameter   and   a
request   for   public   comment  on  this
proposal has been published in the Federal
Register   (40FR17/62).    This    general
limitation  would  be  implemented in each
subpart  regulation  rather  than   in   a
general  regulation.  Other materials such
as ammonia,  phenol  and  cyanide  may  be
considered  for  limitation  in  the  same
manner as oil  and  grease  of  a  mineral
origin.
     Materials  may  at times be introduced
into a POTW in industrial waste waters for
which no treatment effectiveness data  tor
a  normal  type  POTW are available or for
which  the  known   data   indicate   that
treatment  effectiveness  in  the  POTW is
highly variable or  inadequate.    In  such
cases,  it is obvious that the POTW cannot
be  depended  upon  to   effectively   and
consistently   remove   the  pollutant  in
question.   Under  these  conditions   the
Agency expects to consider the application
of   BPT   or   NSP   limitations  as  the
pretreatment standard for  these   specific
materials.    Materials   which    may   be
included in this  category  would  include
metals  such  as copper, nickel, chromium,
zinc and  arsenic,  and  selected  organic
materiaIs.
    Regulations under sections 301 and 306
generally  have  been established  allowing
the discharge of a  quantity  or   mass  of
pollutant  related to a unit of production
or other production  vector.   This  basis
for   limitation   has   the  considerable
advantage of reducing the discharge of the
amount of pollutants to a finite   quantity
while  encourging  conservation in the use
of  water  and  the   reduction    in   the
generation   of   waste   water  within  a
manufacturing process or  operation.   I he
Agency believes that mass limitations best
fulfill  the  purposes  of  the Act.  Mass
limitations     based      on      similar
considerations appear to be the most sound
and  effective  mechanism for reducing the
amount of pollutants discharged to a  POTW
whenever   such   pollutants   would  pass
through or otherwise be incompatible  with
such  works.    I he  Agency  intends to use
this  concept  of  limiting  the   mass  of
pollutants  discharged  as  the  technical
basis    tor    the    establishment    of
pretreatment     standards     for   many
pollutants.
    The enforcement  strategy,  which  the
Agency   proposes  to  employ  to  achieve
pretreatment    ot    industrial    wastes
envisions  the application and enforcement
of these pretreatment standards  by  State
and   local   bodies  including  the  POlW
receiving  and  treating  the   industrial
waste waters.   It has been determined, that
many  State  and local authorities are not
yet anle to apply production related  mass
limitations.   Moreover,  the Act  does not
provide tor pretreatment permits analogous
to the NPDES permits of section 402.   For
this  reason,   the  Agency,  at this time,
expects   to    promulgate    pretreatment
standards which are oased on the discharge
of   a  specified  quantity  of  pollutant,
related to a production vector  (e.g.,  Ibs
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of  pollutant  per  ton  of  product), but
wnich are stated  as  a  concentration  of
pollutant   in   the   discharge   from  a
particular  industrial  process  or   unit
operation.   It  is  anticipated  that the
rationale  for  the  derivative   of   the
pollutant  concentration standards will be
described in detail  in  the  preamble  to
each    pretreatment   standard   for   an
industrial  subcategory.    It   is   also
anticipated    that    restrictions    and
constraints against water use and dilution
may be included when appropriate for  each
subpart.    It   is   intended  that  such
pretreatment standards be applied  at  the
individual  process unit.  Additionally an
alternate   procedure   will    be    made
available,  as  is  appropriate  for  each
subpart, so that mass  limitation  may  be
applied  if  both  the industrial user and
POTW operator desire.
    The Agency believes that  the  use  of
pollutant concentrations as a pretreatment
standard  for  those  materials  which may
pass through untreated, or  are  otherwise
incompatible  with  a  POTW  is an interim
measure made necessary  by  the  practical
constraints   of   enforcement.   At  some
future  revision  of  these   pretreatment
standards, the Agency anticipates that the
concentration  numbers  will  be abandoned
and the mass limitation  will  become  the
sole pretreatment standard.
    All   of  the  pretreatment  standards
being considered are intended to apply  to
users of a "normal type" of publicly owned
treatment   works   which   is   basically
designed and intended  to  treat  domestic
waste  waters  to  achieve  the  secondary
treatment standards as established  in  40
CFR  133  and as required by the Act.  The
secondary treatment standard requires that
a sewage treatment plant, in  addition  to
controlling  pH and fecal coliform, reduce
the amount of  biochemical  oxygen  demand
(BOD5)  to  85  percent  or  less  of  the
influent  value  or  to  30  mg/1  in  the
discharge,    whichever    is   the   more
stringent.   A  similar   restriction   is
applied to suspended solids.
    There are a number of sewage treatment
systems,  which when properly designed and
operated, meet  these  requirements  on   a
consistent   basis.    These  include  the
activated   sludge    system    and    its
modifications,    trickling  filters,  and
stabilization  lagoons or oxidation  ponds.
There  are  a  number  of activated sludge
system  modifications  which   incorporate
variations   on   the   amount  of  sludge
recirculation, the amount of air or oxygen
supplied to the reaction chambers, the use
of pre- and post-chlorination, and the use
of sludge digestion, sludge combustion, or
land filling as mechanisms tor disposal of
the sludge generated.  The retention  time
of  sewage  in  such  systems generally is
short; it is nominally considered to be  6
hours  while retention times as short as 3
or 4 hours are  not  uncommon.   Trickling
filters  are  often  used  where the input
waste water  is  relatively  constant  and
where   savings   in  power  and  operator
attention   are   needed.    Stabilization
lagoons  or  oxidation  ponds  can be used
where the necessary land area is available
and where climatic and soil conditions are
such  that  the   long   retention   times
required  by  such lagoons or ponds can be
achieved.  "A normal type" POTW should not
have   regular,    substantial    chemical
additive needs for the purpose of removing
materials other than BOD and TSS.
    Existing   publicly   owned  treatment
works rarely  include  processes  such  as
physical chemical treatment (wnich is only
now becoming a full scale reality in a few
areas) or special variants or combinations
of  biological  treatment  units  that are
primarily intended to address the  special
needs of industrial waste water pollutants
rather   than   domestic  waste  or  water
quality requirements.
    Variations   from   the    promulgated
pretreatment standards may be necessary in
certain  circumstances  to  compensate for
factors  not  adequately   considered   in
establishing  these  standards.   This has
been recognized in  the  establishment  of
other  industrial effluent limitations and
is  equally  applicable  to   pretreatment
standards.   Two  kinds of variants appear
to  be  appropriate   depending   on   the
particular circumstance.
    In  the preparation of the development
document for each  point  source  category
all  of  the  information which the Agency
could  collect  concermna  processes  and
procedures   related   to   the   industry
subcategory was  collected  and  analyzed.
It  is  possible,  however,  that  certain
facts did  not  become  available  to  the
Agency   and  could  not  be  employed  in
decisions related to the pollutants  which
may   be   discharged  from  a  particular
industry operation or would be related  to
the  treatability  or  impact  which   such
pollutants might have upon  a  POTW.   For
                                            641

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this reason, a variance clause is provided
which  would  allow the establishment of a
pretreatment  standard,  other  than  that
promulgated  in the applicable subpart, in
those cases where it could be  shown  that
factors  related  to the industry category
fundamentally   different    from    those
considered  in  the  development  document
               these factors  require  the
               of a different pretreatment
exist and that
establishment
standard.
    An analogous situation may occur  with
respect to factors related to the publicly
owned  treatment works.  A
is   provided   to   allow
pretreatment  standard  to
for those cases  where  a
treatment   works   can
substantially different
type
which
                           variance clause
                             a   different
                            be established
                           publicly  owned
                         be  shown  to  be
                         from  the  normal
      of publicly owned treatment works on
       pretreatment  standards  are  being
based.     Some    of   these   types   of
installations are known to exist or are in
the planning or design stage.  However, at
this time it is difficult to  establish  a
separate  regulation  which  would make an
allowance for different  factors  in  such
publicly owned treatment works.
    Although  both EPA and the States will
play major roles in enforcing pretreatment
requirements,  the  Agency  believes  that
local  governments  will  probably have to
play  the  most  important  role  in   any
successful   enforcement  program.   Local
governments operate the POTWs, which are a
vital part of the overall effort to  clean
up  the  nation's  waterways,  and  so are
sensitive to and directly affected by  the
pretreatment program.  They are closest to
the  problem  and  are  already frequently
involved  in   related   areas   such   as
regulation  of  sewers  and  collection of
user charges.  Moreover, a local  role  in
pretreatment   enforcement  is  consistent
with the partnership of Federal and  local
effort  found  in  the construction grants
program and other parts of the Act.
    As those with the most immediate stake
in  the  success   of   the   pretreatment
program,  both  in  terms of protection of
the proper functioning of the POTW and  in
terms   of   protection   of   the   local
environment, local governments will be the
first line of defense.  One way  they  may
exercise their crucial role is by means of
a  local  ordinance - a preferred route, and
one specifically preserved by the Act.  It
is   expected   that  each  manager  of  a
treatment works  would  provide  for  such
standards." Local governments may also use
the  citizen  suit  provisions  of section
505.  Section  505  is  available  because
local governments are "persons" as defined
in the Act "havinq an interest which is or
may  be  adversely affected".  The citizen
suit provisions allow suit  to  enforce  a
Federal  or  State  pretreatment  standard
either against the industrial user of  the
POiW  or  against  the  State  or  Federal
government (for  failure  to  take  proper
action).    The  Agency  anticipates  tnat
pretreatment guidance  published  pursuant
to section 304(fj will be of assistance to
local  governments  in  carrying out their
responsiblities.
    The  Agency  believes  that   parallel
efforts  of all three levels of government
will   be   needed   for   a    successful
pretreatment   program.   To  the  maximum
extent possible, FPA  will  encourage  and
assist State and local enforcement action.
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                   MUNICIPAL SEWER UTILITY FINANCING UNDEP. PL 92-500*

                              C. C. Taylor, Program Analyst
                             Environmental Protection Agency
                              1421 Peachtree Street, N. E.
                                 Atlanta, Georgia 30309
                                        ABSTRACT

     The Water Pollution Control Act Amendments of 1972 imposed significant financial
requirements upon grantees under the Federal Construction Grants Program administered by
the Environmental Protection Agency.  This paper discusses the legislative history and
implementation experience of these grant conditions which are commonly referred to as the
user charge and industrial cost recovery requirements.

     All recipients of Federal construction grants must demonstrate legal, financial, and
managerial capability to complete construction and provide adequate operation and main-
tenance during the life of the facility.  Grantees must also develop and implement user
charge systems whereby all users pay the costs of operation, maintenance and replacement
in proportion to their use of the treatment facility.  Such charge systems must also in-
clude provisions for reimbursement of Federal construction costs allocable to industrial
users.

     The Environmental Protection Agency's implementation of these statutory requirements
is impacting the institutional pattern of municipal sewer utility management.  More
adequate operation and maintenance is assured, and greater equitability in the distribu-
tion of costs is being attained.

     Public response to the imposition of user charges has been reasonably receptive.
Compliance with industrial cost recovery requirements continues to generate controversy,
particularly with respect to applicability, cost allocation, and accountability.
              INTRODUCTION

     During the long and somewhat torturous
legislative history of The Water Pollution
Control Act Amendments of 1972, the Honor-
able Robert E. Jones of the U. S. House of
Representatives characterized this legis-
lation for his collegues as follows:  "Mr.
Chairman, this is an enormously complex
bill, and necessarily so, because our water
environment has become enormously compli-
cated because of the urbanization and in-
dustrialization of our society.  Our legis-
lation must take into account the myriad
of the water needs issue" (1).**

     Subsequent to enactment, the act has
been called many things, ranging from the
most significant legislation of the decade
to the most comprehensive, the most com-
plex and the most confusing legislation
ever enacted at any time or place in the
history of man.  Whether or not either of
these latter characterizations are justi-
fied, PL 92-500 is, without doubt, compre-
hensive in scope.  Many of its provisions
are complex, and implementation of some of
 *Paper prepared for presentation at Fourth
  U. S./Japan Conference on Sewage Treat-
  ment Technology, Washington, D. C.,
  October 28-29,1975.
**Numbers in parentheses designate refer-
  ences on page 6.
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the provisions have been accompanied by some
confusion and controversy.  This includes
implementation of significant provisions
relating to cost-sharing and cost alloca-
tion.  The emphasis of this paper is fo-
cused upon these financial aspects of the
subject legislation.

         BACKGROUND OF PL 92-500

     In the spring of 1967, a joint Commit-
tee of the American Public Works Associa-
tion, the American Society of Civil
Engineers, and the Water Pollution Control
Federation reviewed the most significant
problems of the broad area of administra-
tive, legislative, and financial issues of
municipal water and sewer service.  As a
result of the initial review, the Commit-
tee decided to focus its activities upon
the most urgent area, namely wastewater
financing and charges  (2).  This was indic-
ative of the general conclusion that most
of our municipalities were not adequately
prepared, at that time, to assume and
manage the rapidly escalating financial
and  administrative responsibilities of
sewer service.

     A leading management consultant firm,
working under contract with EPA Region
VIII, found this general  situation little
changed by 1972  (3).  Our nation is, of
course, geographically large and widely
diverse with respect to political structur-
ing.  Obviously, this broad generalization
did  not apply to all municipalities indivi-
dually.  However, as a general rule, munic-
ipal sewer utilities were operated largely
as a public service financed by annual
appropriations from general revenues.
Generally, cost  accounting systems, and
their attendant  legal  and financial insti-
tutions were not adequate for efficient
operation as  financially  self-sustaining
public utilities.   It was in this atmos-
phere that The Congress deliberated legis-
lation which  culminated in PL 92-500.

     During this legislative process, many
complex and controversial issues were dis-
cussed and debated, after which  some were
resolved  and  some apparently compromised.
These deliberations are reflected in the
'Committee and conference  report  (1).

     Of  the significant issues debated,  two
pertain  directly to our subject  of  finan-
cial management.  First,  Congress  fully
recognized that  the costs of attaining
the desired levels of clean water were
going to be large - we might even say
enormous.

     The most recent "Needs Survey" cost
estimate for the backlog of municipal
facilities which are normally funded under
the EPA Construction Grant Program - that
is, only treatment facilities and attendant
interceptors and outfalls - was at the
level of approximately 50 billions of
dollars (4).  We have known for some time
that attainment of the desired levels of
pollution control was going to be costly,
and Congress was fully aware of this as
they legislated this act.

     Second, the committee reports reflect
that Congress also was fully aware of the
basic necessity of getting maximum return
for each dollar of this enormous investment
and that this could be done only with im-
proved and adequate operation and mainte-
nance.  Why go to the expense of building
these facilities if they were not going to
be operated and maintained in such a way
that they would do the job for which they
were designed?

     As a result of these deliberations,
the Congress reached some basic decisions.
First, the level of Federal cost sharing
for the construction costs of the large
backlog of needed publicly-owned municipal
facilities would be raised to 75 percent.

     Second, it would be necessary to find
some way to move our municipal sewer sys-
tems to a sounder financial basis whereby
thev could become more financially self-
sufficient.  This should be done by pro-
moting a shift of the sewer service
function from a public service basis to a
public utility basis whereby;

     a.  Wastewater treatment and control
         service would be paid for by the
         users of that service.

     b.  The users would pay these costs on
         the basis of the extent of their
         use of the system.  In this way,
         there would be an economic and
         financial incentive to reduce
         waste discharge or at least hold
         it to an amount for which each
         user would be willing to pay.

     Third, after extended, and apparently,
heated debate about the Federal funding  of
                                            644

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publicly-owned facilities which would
treat industrial wastes, the Congress
reached this basic conclusion.  The Feder-
al Construction Grant Program was ini-
tially designed to provide Federal funding
aid to municipalities for the large back-
log of needed facilities.  Consequently,
it would not be appropriate for this fund-
ing program to provide a subsidy to indus-
trial users of municipal facilities.  This
would be significant economic and financial
discrimination against those industries
that did not have the opportunity of
discharging to municipal, publicly-owned
facilities (5).

     These conclusions are articulated in
Section 204(b)(l) of PL 92-500 in the
form of three basic provisions:

     1)  For all projects funded with
         Federal construction grants, the
         grantee must demonstrate legal
         and financial capability to com-
         plete construction of the
         facilities and to adequately
         operate and maintain the facili-
         ties throughout their useful
         life.

     2)  The grantee must agree' to develop
         and put into effect a user charge,
         sewer service fee system whereby
         all users of the system will pay
         a share of the operation, main-
         tenance, and replacement costs
         in proportion to their use of
         the system.

     3)  For all such grant assisted pro-
         jects that treat industrial
         waste, the charge system must
         include provisions for industrial
         users to pay back to the grantee
         their proportional share of con-
         struction costs, at least to the
         extent of the Federal grant.

     The latter two provisions were essen-
tially new limitations of the Federal Con-
struction Grants Program, and EPA experi-
ence with their implementation impinges
upon the current pattern of municipal
sewer utility management.  These are the
provisions of PL 92-500 commonly referred
to as the user charge and industrial cost
recovery grant requirements (6).
         EPA EXPERIENCE WITH USER
    CHARGE AND INDUSTRIAL COST RECOVERY
             GRANT CONDITIONS

User Charges For OM&R Costs

     It is clearly apparent that the pri-
mary objective of the statutory require-
ment for a user charge system is to assure
sufficient revenue for adequate operation,
maintenance, and replacement of operational
components during the useful life of the
grant-assisted facility.  There has been
almost universal acceptance of this objec-
tive, in principle.  With the exception of
some normal resistance to rapidly increas-
ing charges as higher levels of treatment
are installed, the users of municipal sewer
service have been quick to grasp the logic
of maximizing returns from these large
capital investments through more efficient
operation and maintenance.  Likewise, they
appear to have readily accepted the
necessity of raising sufficient revenue for
this objective.  There has been far less
universal acceptance of the source of
revenue and the distribution of these
revenues as required by interpretation of
the statute.

     At the time this legislation was in-
acted, a significant proportion of our
municipalities obtained some or all reve-
nues for provision of sewer services from
ad valorem property taxes and other non-
user sources.  Many municipalities continue
to do this for some components of total
costs.

     In consideration of Congressional
recognition of the diversity of legal and
financial factors that existed among juris-
dictions, EPA proceeded to draft regula-
tions which would permit reasonable flexi-
bility in the design of user charge systems
that would meet the unique requirements of
each grantee jurisdiction (5).  This inter-
pretation proposed approval of user charge
systems including ad valorem tax revenues
for OM&R costs if the grantee could demon-
strate that revenue was reasonably propor-
tional to sewer use among major classes of
users.

     The Comptroller General of the United
States ruled that such user charge systems
would not meet the statutory requirements
for proportionality between classes of
users nor among users within classes (7).
                                          645

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Therefore the grant condition currently re-
quires that all OM&R revenue, including
revenue for costs allocable to non-exces-
sive infiltration/inflow and stormwater
treatment, be obtained from user charges.

     This categoric requirement continues
to be controversial and causes implementa-
tion problems particularly where there is
a long established custom of relying on
property tax revenue and where municipal-
ities find it expedient to continue to do
so for funding of local capital costs. The
latter practice, of course, necessitates
carrying the costs of legal and institu-
tional arrangements incident to the two
or more sources of revenue.

     As a consequence of this experience,
EPA has requested amendment of the statute
to permit use of ad valorem based user
charge systems under certain qualified con-
ditions.  This amendment is now pending
before Congress.

     Another significantly controversial
aspect of the user charge grant condition
is the criteria of average-unit pricing
with no significant quantity discounts. We
have a long historical pattern of public
utility rates based upon marginal-unit
pricing,  affording significant quantity
discounts to large-volume users.  Such a
pattern applied to most public utility
services  such as electric power, natural
gas, water supply, and sewer service.

     In order to provide an economic and
financial incentive to minimize waste dis-
charge as well as promote the principle of
imposing  the costs of pollution abatement
directly  upon the source, the statute was
drawn to  require that user charges for
OM&R be based directly upon  factors that
significantly affect  those costs.  Although
our agency implementation policy provides
for considerable flexibility in the alloca-
tion of OM&R costs among parameters of flow
and flow  characteristics, as well as flexi-
bility in the allocation of  costs not di-
rectly related  to these parameters, our
policy requires essentially uniform rates
for comparable  services among all users.

     This grant limitation criteria often
accounts  for the most significant shifts
in  relative  cost distribution among
classes of users, particularly  for a shift
in  relative  cost burden from the residen-
tial class to the industrial class.  Ob-
viously, the extent of change in either
the magnitude of costs or the relative
distribution of those costs is dependent
upon previous levels of service and charges
with which current conditions are compared.

     EPA regulations require that the
grantee implement the user charge system
throughout the entire service area to cover
OM&R costs on all facilities.  We are
pleased to learn that this criteria has
encountered relatively few problems with
the exception of some difficulties in ob-
taining necessary agreements with recipient
communities in regional systems.

     Although our agency experience is re-
latively limited, there seems to be little
doubt that operation and maintenance will
be materially improved by assurance of more
adequate revenues.  As the pollution abate-
ment cost burden inevitably increases, our
experience would appear to indicate that
the attainment of greater equitability is
also conducive to accomplishing our major
water quality goals.

Industrial Cost Recovery of Federal
  Construction Costs

     As previously indicated, a significant
Federal construction grant condition is the
requirement for reimbursement of Federal
construction costs allocable to industrial
users.  Although there is a long precedent
for such reimbursement of Federal funding
in the water resource development field,
this feature is entirely new to the Federal
grant program for sewer construction.

     Immediately subsequent to enactment,
there was public criticism from the indus-
trial sector.  Industrial users of munici-
pal systems expressed resentment at being
the only beneficiaries required to reim-
burse the grant assistance.  This argument
was supported by the contention that they
were fully comparable contributors to the
general revenues from which these grant
funds are appropriated.  Although this
criticism has not disappeared, it has
apparently mitigated as industrial dis-
chargers become more aware of the relative
costs of using publicly-owned municipal
systems as compared with privately-owned
facilities.

     KPA implementation problems are more
closely related to the technical complex-
                                           646

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ities of applicability, cost allocation,
and accountability.  Perhaps the best
indication of the scope of these difficul-
ties is the fact that promulgation of fi-
nal agency guidelines is just now nearing
completion.

     It was apparently an objective of
Congress to impose this differential reim-
bursement requirement upon commercial
process wastes from the production of con-
sumer products for which pollution abate-
ment costs could be shifted to product
prices.  In our diverse, but highly inte-
grated and industrialized society, this
delineation of applicability has not
proved to be easily attained.  Such a
criteria clearly extends beyond the
manufacturing category.  EPA regulations
define applicability to include A, B, D,
E, and I divisions of our Standard In-
dustrial Classification System (8).*  This
includes the service industry.  Exemption
from industrial cost recovery is provided
for discharges that are primarily segre-
gated domestic wastes from sanitary
conveniences.  This whole complicated
criteria has almost defied practical im-
plementation.

     Although the issues of cost alloca-
tion are somewhat amenable to technical
analyses,  such analyses have not yet
attained commonly accepted precedents for
the parameters of allocating costs nor for
the distribution of construction costs
among these parameters.  Our regulations
provide for considerable flexibility, in
recognition of the fact that these will
vary significantly by type of facility and
level of treatment.  In the absence of
fairly rigid implementation criteria,
continuing controversy apparently can be
expected as representatives of major user
classes compete for financial advantage.

     In accord with the statute, the
grantee is charged with specific respon-
sibility for collection of the industrial
cost recovery revenues.  The grantee
reverts one-half of this revenue to the U.
S. Treasury and retains the remainder.
Eighty percent of retained revenues must
be used for expansion or replacement of
eligible facilities.  The eligible project
costs for  subsequent grants are reduced
by the amount of unexpended funds re-
tained for expansion and replacement.
     The reaction of grantees to the indus-
trial cost recovery requirement has been
less than enthusiastic approval.  This is
apparently due largely to the rather heavy
administrative burden for which they often
seem to feel they have no incentive to
assume.  This introduces what now appears
to be a most significant implementation
problem for EPA.  Although our implementa-
tion experience in this area is just begin-
ning, the problems of monitoring and audit
accountability are significant.  The grant
conditions will require multiple accounting
procedures for the various revenue accounts.
They may also result in multiple cost allo-
cation and amortization procedures for the
various components of total costs.  These
additional requirements impose upon an
institutional framework that was inadequate
to the task even prior to this imposition.

     This brief discussion of some of the
more significant implementation problems
should be considered tentative and somewhat
exploratory.  EPA feels that progress is
being made and the agency is actively
exploring the potential for improvements
both within the framework of the existing
statute, as well as possible statutory
modifications (9)(10).   Such considerations
are being focused particularly upon the
issues of cost sharing and financial manage-
ment.  It is hoped that our experience is
of interest to you and may be of some help
to you as we pursue our mutual goal of an
improved environment.
*A-agriculture, forestry and fishing; B-
mining; D-manufacturing; E-transportation,
communications, electric, gas and sanitary
services; and I-services.
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                                       REFERENCES


 1)   A Legislative History of  The Water Pollution Control Act Amendments of 1972,
     Committee Print  Serial No.  93-1,  Library of Congress, Vol.  1, January 1973,
     page 356.

 2)   Financing and Charges For Wastewater Systems,  A Joint Committee Report, American
     Public Works Association, American Society of Civil Engineers, Water Pollution
     Control Federation,  1969.

 3)   Financial and Institutional Arrangements For Wastewater Management, Denver SMSA,
     by Wilbur Smith  and  Associates,  Environmental Protection Agency, April 1973.

 4)   Cost Estimates For Construction  of Publicly-Owned Fastewater Treatment Facilities,
     1974 "Needs" Survey, Final  Report to the Congress, Environmental Protection Agency,
     Revised May 6, 1975.

 5)   Report of The Committee on  Public Works United States Senate, Together with
     Supplemental Views to Accompany  S2770,  Report No. 92-414, USGPO, Washington,
     D. C., 1971, pages 28-30.

 6)   Public Law 92-500, 92nd Congress, S2770, October 18, 1972,  Section 204(b)(l).

 7)   Comptroller General  of the  United States, Decision File B-166506, July 2, 1974.

 8)   Standard Industrial  Classification Manual 1972, Executive Office of The President,
     Office of Management and  Budget,  USGPO.

 9)   Evaluation of Alternative Methods For Financing Municipal Waste Treatment Works,
     Socioeconomic Environmental Studies Series, Office of Research and Development,
     EPA, 600/5-75-001, February 1975.

10)   Analysis of Cost Sharing  Programs For Pollution Abatement of Municipal Wastewater,
     Socioeconomic Environmental Studies Series, Office of Research and Development,
     Environmental Protection Agency  600/5-75-031, November, 1974.
                                           648

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                      A PERSPECTIVE ON MUNICIPAL POLLUTION CONTROL -
                        THE CONSTRUCTION GRANTS PROGRAM & PL 92-500

                                       John T  Rhett
                              Deputy Assistant Administrator
                            Office of Water Program Operations
                           U  S  Environmental  Protection Agency
                                  Washington, D  C  20460
                                         ABSTRACT

     The Federal  Water Pollution Control  Act Amendments of 1972 provide for an $18 billion
program for construction of municipal  wastewater treatment works.   Almost $11  billion of
that sum remains  to be obligated.  However, the pace of obligations is rapidly increasing
to a goal  of $400 million per month.   Problem areas encountered in implementing the program
in its first three years include the  1977 deadline for secondary treatment, user charge
requirements, program management, personnel needs and participation of State agencies.
Specific actions  to remedy these problems have been taken, including proposing amendments
to the law.  Several  major areas of the program wilI  receive attention in the future
including institutional systems, operation and maintenance, development and demonstration
of new technology and construction needs and priorities.  EPA expects to make recommenda-
tions to Congress on future funding of the program.
                  TEXT

     My topic today, the Federal  Water
Pollution Control  Act, as amended in 1972,
is a subject that gives me great pleasure
to address.   I  appreciate this opportunity
to comment on the strengths and shortcom-
ings of the law, and some current admini-
strative and legislative initiatives as
they pertain to the Municipal  Water Clean-
Up Program.

     Since one of our major administrative
tasks under the law is to provide funds to
get construction of municipal  treatment
works rapidly underway, I  am happy to
report first on the status of  obligations.
As you may know, obligations are Federal
funds that are committed as grants to cover
75 percent of the eligible costs of specific
municipal  wastewater treatment construction
projects.  And,  our EPA grants  program is
quickly becoming the world's largest single
pub Ii c works program.  A I most  $ I I  b i I I ion
rema i ns from our $18 billion author!zation,
and we are moving quickly to obligate all
of that sum by the statutory deadline,
September, 1977.
     Currently, our obligations under the
new law have reached over $7 bi I I ion and
projects being completed under the old law
have grants of $4.3 billion.  Further, our
monthly obligation rate in FY  1975 averaged
about $186 million over the FY 1974 rate.
We went from $115 mi I I ion to over $300
million, and we confidently expect to raise
our average over $100 million more to reach
our goal of over $400 million per month for
this fiscal year.

     I  am a I so pleased to report that the
Federal  reimbursement program to municipal-
ities is almost completed.  This is for
construction begun in advance of the Federal
grant,  and which is considered eligible for
a grant.  Over $1.6 billion has been obli-
gated and over $1 billion paid out.  And,
the half a billion dollars in remaining
funds are presently being awarded.
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     Translating investments into projects
we have more than 4,000 individual projects
funded at 75 percent underway and almost
2,000 additional projects still being com-
pleted under the old law.   Once finished.
our new law projects will  constitute a $24
billion total investment in public waste-
water treatment works,  and added to the
public wastewater treatment works we have
under the former grants program, our
national  treatment investment would approx-
imate $42 billion by the year  1977,

     At the present date,  we are almost
half-way towards our goal  of obligating all
the grant monies that were authorized under
PL 92-500, but the most heartening fact in
this report is the rate at which the fund-
ing levels have increased this past year.
The progressive picture today presents a
contrast with the program in earlier days.
To appreciate our progress and the initia-
tives and actions that are currently pend-
ing, we must step back in time.

     By last year the criticism directed
at the program and the law,  PL 92-500,  had
mounted to a very high  level.   The concerns
that were voiced were so general they
caused questioning of the program's
credi bi Ii ty.

     To cite just a few of the major
issues, critics attacked:

     —The goals of the Act.   "They were
impossibly idealistic."

     —The funding of the  Act.   "It was
inadequate to meet the  'needs'.''1'

     —And the deadlines were "unreal-
i stic."

     None of the legal  mandates antici-
pated  the capital  funding  requirements  nor
the local  difficulties  in  raising the
matching  share of 25 percent.   Moreover,
as delays lengthened, the  costs continued
escalating.   Construction  costs had risen
at the rate of 15 percent  per annum,  and
only recently have they shown any signs of
abatement.

     The  secondary treatment deadline,
within the Act,  and the need to amplify
the States'  role have also called for
legislative change.   Since many of the
project planning decisions that must be
made are  based primarily on  "best judgment,1'
and the best planning information  i's
 ocated at the State and municipal  level,
the lack of any real provision for State
participation has riveted our attention.

     At a  less fundamental  level, often
there are pleas to simplify the  law, to
cut "red tape" and paperwork.  Indeed,
this is incorporated in a provision of the
law, in Section IOI(fl.  The classic reply,
of course, is in the law  itself.   That
section appears on page 2, but the law
continues for another 86 pages of fine
print,  and almost every page calls for
more regulations,  guidelines and reports.

     Personnel at a I I levels of the effort
in both the public and private sectors
have generally been too few. In facilities
planning, for instance, no  less than ten
major categories of requirements must be
cons i dered.

     Also, there has been the requirement
for an equitable system of user charges.
The requirement was conceived as an incen-
tive to water and sewer customers to con-
serve water and cut individual  use.  Un-
fortunately,  the requirement also placed
large administrative and cost burdens on
communities with existing ad valorem
property-based methods of taxation. On
this subject, a California State Repre-
sentative recently testified that it would
cost the Sanitation Districts in Los
Angeles County, not including Los Angeles
City,  over $2 million a year in additional
accounting expenses to administer the
required system.  In short, the user
charge concept was environmentally sound,
but it was fiscally unsound, in some cases.
It failed to take into account established
local,  revenue-raising practices or the
administrative costs of change.

     The recovery of the  industrial share
of treatment construction costs is an
allied subject, but since Mr. Taylor will
be addressing that area of the law, I wi I I
pass over some recent developments there.

     So far,   I have mentioned only a few
of the issues that have "cropped up. -
As you know,  there have been others, and
it sometimes seemed  last year that the
issuance of almost all  the  required,
baseline regulations and guidance by the
Agency went  largely unnoticed.
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     But, that was  last year, and the year
before,  This year,  I am happy to note that
our progress has been pa.pid, and our momen-
tum Is gaining strength.  There are several
reasons for this and the chief factors,  I;
believe, are the experience we have so
painfully gained, and the widespread cooper*
ation we have enjoyed in devising, and
implementing the needed changes,

     It is also true that "nothing
succeeds like success.^  Recent progress
has bred a spirit of optimism in the pro-
gram. We have been moving to simplify
procedures and strengthen management, and
where changes are not legally permissible
because the law is over specific, we have
been promoting legislative amendments.

     Concerning the administrative changes,
last November, as the result of some rn-
depth study and program analysis by our-
selves and others, we began meeting with
representatives of the various interest
groups involved in the program^—the State
and local governments, the consulting
engineers, contractors, and wastewater
equipment manufacturers.

     The recommendations and strong
cooperation we have recently received have
enabled us to further simplify and stream-
line the granting procedures and provide
guidance in fulfilling them, particularly
for those applying to the earliest stages
of planning.  We have also improved our
monitoring capabilities, to project future
funding commitments and identify lags and
individual  projects needing action.   We
have reorganized for more central manage-
ment and accountability for the individual
projects and the program as a whole,  In
the Regions and in Headquarters.   Since we
have received  authorization, we are cur-
rently recruiting and instituting training
for 400 additional  positions in the program.
But most important,  for some time,  we have
been encouraging the States to assume large
parts of the program by assuming larger
review and  certification responsibilities
for project plans and specifications  and
for reviewing  infiltration/inflow and
operation and  maintenance provisions.   We
are also helping  the States to strengthen
their own program activities through
increased Section 106 funds, and urging
the use of  part of the construction  grants
funds,  i f needed.
     In this latter effort, we have suc-
ceeded in encouraging more than half the
States to assume extra grant responsibil-
ities.   Their management cost increases can
currently be covered by withdrawing a sum
up to one-half of one percent of their
total Federal allotment, and the State of
California is taking advantage of this
funding option.  Alternatively,  our EPA
budget that  is presently before Congress
for approval  contains extra funding
requests to strengthen the States'
programming and planning capabilities.

     Cumulatively, there has been a good
deal of action on the management side this
past year,  When  I consider the total
impact of the recent and emerging develop-
ments,  I  am greatly pleased with our pro-
gress in the program.   In addressing the
problem areas, we have  introduced a good
deal of administrative flexibility.

     For the areas we have been unable to
address administratively, new legislation
has been introduced,  A bill to amend
PL 92-500, H,R  9560, is currently await-
ing further attention by the House Public
Works Committee,  Our Administrator,
Mr, Train, testified on it at some hear-
ings recently.  Briefly, its major grant-
impacting provisions are these:

     — First, it does contain a provision
a I lowing ad valorem taxation to assess
user charges.  However, we believe it is
over-broad and should be limited to only
those areas where it has been used
histori caIly.

     —Second, it does delegate the
major construction granting authority to
the States.  Since we have been working
closely with the Public Works Subcommittee
on this amendment for some time, and
although we  do have reservations on the
procedure for suspending State certifica-
tion, we are, for the most part, pretty
welI satisfi ed wi th it.

     —Third,  it does extend the secon-
dary treatment deadline to July,  1982.  On
this issue, the Administrator felt the
extension should be granted until July,
1983 when Best Practical Treatment would
be  required.  He also indicated the exten-
sions should be on a case-by-case basis,
and the non-availability of Federal  fund-
ing should be a justification for granting
                                          651

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an extension.  Ocean discharging municipal-
ities, we feel, should not be singled out
in the amendment since their discharges can
be considered for extension along with the
others, if the delay is merited.

      Parenthetically, the Task Force on
Municipal Ocean Outfalls recommended that
ocean dischargers, where the need for
secondary treatment is uncertain, should
have prime consideration for Step I  planning
grants to determine their water quality
impacts, but should not be given much
priority for construction grants, unless
indicated by the Step  I study.

      The remaining provisions of the bill
relate to increased funding for State pro-
gram and areawide planning above what we
requested in our Agency budget.  As
Mr. Train indicated, we disapprove extend-
ing areawide planning  under Section 208
beyond the initial two years, nor should
the 75 percent Federal funding share be
increased to  100 percent, as proposed.

      Encouragement of strong  local  parti-
cipation  in  planning should be premised on
some degree  of funding commitment by the
localities directly involved.  As for the
bill's proposal to provide more funds to
reimburse advanced construction, we did
not support  this because we do not think
it would buy any additional clean-up of
the waters.

      Taken  all together, and especially
if our recommendations are adopted, we
feel that the  bill will significantly
alleviate the  short-term problems of the
program.

      As for the  longer-term problems
affecting the more distant water quality
goals of the  law, the  National Water
Quality Commission's findings, which will
be discussed  later, when they  issue  in
final form,  will be a  prime factor next
year  in determining the final form these
goals will assume.  Based on the draft
version of the staff report that is
currently circulating,  I am very encouraged
by the fact  that the municipal treatment
costs seem pretty close to our own projec-
tions, and the tone seems generally  favor-
able to continuation of the effort.

      Looking  ahead in the program,  I see
several major  areas of concern.  What  is
particularly needed right now,  it seems to
me, is more information on the  institu-
tional systems, in the  localities and
particularly the States, that increasingly
are becoming involved; on the stresses
and strains on these systems; and some
assessment of the abilities needed to
assume the more substantive parts of the
program.

      Another concern  is with the preserva-
tion of adequate operations and mainten-
ance  in the plants.  As more plants with
more sophisticated treatment equipment
go on line, operating efficiency will be
assuming even greater  importance.  For
these reasons, we have begun actions to
strengthen the States' capabilities in
operator training and certification
programs, also in monitoring.

      A third concern  is to encourage the
development and demonstration of innova-
tive wastewater treatment technology.  We
are presently in the early stages of
developing some possible new legislative
initiatives to fill this program need
which, hopefully, will be ready for pro-
posal  to Congress next year.

      Finally, we are concerned with the
new State Needs Survey that is just about
to get underway.  As you may know, we
hope to identify from  it where we are in
terms of reaching our goals, and how far
we need to go.  In conjunction with this,
we will  also be scrutinizing closely the
State priority lists to be sure the
important selection criteria are empha-
sized.  We want to be sure the public
funds are not misapplied to projects with
marginal benefits to water quality and
that the needs that Congress has identified
in the  law — for advanced and secondary
treatment and for  interceptor sewers —
receive first consideration.  We want to
be sure, in order that we reach our
national goals as quickly as possible,
that projects emphasized first are those
in the critical water quality areas that
are required to meet the standards and
enforcement provisions of the  law.

      While on the subject  of needs and
priorities,  I would  like to point out
that the largest need  1 foresee  in this
program  is for some assurance of future
funding continuity.  Municipalities  should
have some assurance the funds will be
there to build and complete their projects
before they willingly  commit themselves
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to raise the local funds to pay for planning.
Commitments should be made on all  sides,
and the communities should not have to  live
under the threat of on-again, off-again
Federal assistance.

      To learn the views of the public and
the professions on how the program should
be financed beyond the current authoriza-
tions, and how the secondary treatment
requirements for municipalities by 1977 or
1978 should be treated when they would be
unattainable, EPA held a series of public
hearings last June.   In summing up the
results, as a whole we found a consensus
on the necessity to achieve secondary
treatment or higher, as required by water
quality considerations.  Also, we found
some support for giving stormwater treat-
ment  less emphasis and a lesser priority
status, and on extending the  1977/1978
secondary treatment deadline on a case-by-
case basis.

      After we evaluated these responses
and recommendations, we made some estimates
based on the cost figures for the 1974
State Needs Survey.  As you may know, the
total State needs identified  in the  1974
Survey, as adjusted, would cost over $342
billion, including the cost of treating
and controlling stormwaters, at $235
billion.  Since this total  sum was just
too  large to be seriously contemplated,
we examined the individual  treatment cate-
gories  in terms of the priorities of the
Act, and their relative impact in attain-
ing cleaner water.  And we excluded the
$235 billion for stormwaters.  Since our
purpose was to devise a strategy to
"optimize" Federal funding, we chose pro-
jects to provide secondary and advanced
treatment, and interceptor sewers, and to
correct sewer  infiltration/inflow problems
for primary funding emphasis.

      And based on our findings and esti-
mates, we expect to make recommendations
to the Congress on how the program should
be financed in the future.   As you may
know, we favor a varied Federal funding
share depending on relative  importance to
our clean water goals.  And needless to
say, this would be premised on continued
program funding at a higher  level  for
several more years, following the lapse
of the current PL 92-500 authorization.
      Parenthetically, I  understand Japan
is also moving to greatly increase its
national funding to municipal treatment
projects.  I  would like to encourage
Japan in the significant commitment that
will be proposed for national endorsement,
The five-year, $30 billion program that
is planned, if adopted in its entirety,
would constitute a 400 percent increase
over Japan's present level of program
funding for such construction.  I  commend
your dedication to this significant and
laudable water clean-up effort.

      In conclusion,  I would  like to
mention some ancillary benefits we expect
to derive from the program.   Aside from
improved water quality — and since the
projects under PL 92-500 are not yet
completed, the progress we are seeing is
primarily derived from our predecessor
law — one major benefit is  to the
nation's economy.  For instance,  employ-
ment on the public treatment works is
expected to reach a peak of  296,000 new
jobs per year in 1977, and remain at over
100,000 jobs through 1983.  Overall,  in
the decade between 1975 and   1985,  the
National Water Quality Commission has
tentatively estimated that implementation
of the Act could create a total of nearly
one and one-half million man years of
work to construct the required treatment
works.  And the "ripple effect" in the
economy wi I I  probably create an equal
number of additional  jobs.

      This is a substantial  benefit to
the nation, but we are not losing sight
of our basic objectives — to clean up
our water  in the most cost-effective
manner possible.

      In pursuing this goal, we welcome
the opportunity to exchange   information,
technology and experience with our
Japanese counterparts.  Although you
operate under different  laws, our overall
goals are similar.   I believe these
exchanges are valuable to our own water
clean-up program, and I  wish to take this
opportunity to thank the Japanese Govern-
ment for your significant contributions
to  improving the water environment of
the world.

      Thank you.
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                                    COMMISSION CHARGE
                           TENTATIVE STAFF ISSUES AND FINDINGS
                          NATIONAL COMMISSION ON WATER QUALITY
                                    J. G. Moore, Jr.
                                    Program Director
                          National Commission on Water Quality
                                    Washington, D. C.
               INTRODUCTION

     On October 18, 1972, the Congress over
a Presidential  veto, enacted Public Law
92-500 — the Federal  Water Pollution
Control .Act Amendments of 1972.  Respond-
ing to public demand for cleaner water, the
law it enacted  culminated two years of
intense debate, negotiation and compromise,
and resulted in the most assertive step
in the history  of national  water pollution
control activities.

     In their deliberations, Congress
determined that the prior program was
making too little headway in redressing
the serious problems of the Nation's
polluted waters.   John Blatnik, then
Chairman of the House Public Works Com-
mittee, testified to the new sense of
immediacy of the  task at hand -- cleaning
up the Nation's waters:

     "In this measure, we are totally re-
structuring the water pollution control
program and making a far-reaching national
commitment to clean water,  much as our
space program was restructured a decade ago,
when the late President Kennedy committed
America to a landing on the moon before
the end of the  1960s."

     Senator Muskie, bringing the Bill to
the Senate floor, stated:

     "...today, the rivers  of this country
serve as little more than sewers to the
seas.  Wastes from cities and towns, from
farms and forests, from mining to manufac-
turing, foul the  streams, poison the
estuaries, threaten the life of the ocean
depths.  The damage to health, the envi-
ronmental damage, the economic loss can
be anywhere."

     The Act, P.L. 92-500, departed in
several ways from previous water pollution
control legislation.  It expanded the
Federal role in water pollution control,
increased the level of Federal funding
for construction of publicly owned waste
treatment works, elevated planning to a
new level of significance, opened new
avenues for public participation and
created a regulatory mechanism requiring
uniform technology-based effluent standards,
together with a national permit system for
all point source dischargers as the means
of enforcement.

     In the strategy for implementation,
Congress stated requirements for achieve-
ment of specific goals and objectives
within specified timeframes.  The objective
of the Act is to "restore and maintain the
chemical, physical, and biological integrity
of the Nation's waters."  In addition, two
goals and eight policies are articulated.
The goals are:

     -- To reach, "wherever attainable", a
water quality that  "provides for the pro-
tection and propagation of fish, shellfish,
and wildlife" and "for recreation in and on
the water" by July  1, 1983.

     -- To eliminate the discharge of pol-
lutants into navigable waters by 1985.
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The policies are:

     -- To prohibit the discharge of toxic
pollutants in toxic amounts.

     — To provide Federal financial assist-
ance for construction of publicly owned
treatment works.

     -- To develop and implement areawide
waste treatment management planning.

     -- To mount a major research and
demonstration effort in wastewater treat-
ment technology.

     -- To recognize, preserve and protect
the primary responsibilities and roles of
the States to prevent, reduce and eliminate
pollution.

     -- To insure, where possible, that
foreign nations act to prevent, reduce and
eliminate pollution in international waters.

     -- To provide for, encourage and
assist public participation in executing
the Act.

     -- To pursue procedures that drasti-
cally diminish paperwork and interagency
decision procedures and prevent needless
duplication and unnecessary delays at all
levels of government.

     The Act provides for achieving its
goals and objectives in phases, with
accompanying requirements and deadlines.

     Phase I, an extension of the program
embodied in many State laws and Federal
regulations, requires industry to install
"best practicable control technology
currently available" (BPT); and publicly
owned treatment works to achieve secondary
treatment -- by July 1, 1977 -- as well as
"anymore stringent limitations, including
those to meet (State or Federal) water
quality standards."  (Sec. 301(b)(1)(C)).

     Phase II requirements are intended to
be more rigorous and more innovative.
Industries are to install "best available
technology economically achievable (BAT)...
which will result in reasonable further
progress toward the national goal of
eliminating the discharge of all pol-
lutants";  and publicly owned treatment
works are  to achieve "best practicable
waste treatment technology...  including
reclaiming and recycling of water, and
confined disposal of pollutants"  (BPWTT)
-- by July 1, 1983 — as well as any water
quality related effluent limitation.  (Sec-
tion 302)  Ultimately, all point source
controls are directed toward achieving the
national goal of the elimination of the
discharge of pollutants by 1985.

     The Act was intended to be more than
a mandate for point source discharge control
It embodied an entirely new approach to the
traditional way Americans have used -- and
abused -- their water resources.  Some of
these mechanisms are found in Title I, the
broad policy title; others are woven
through-out the Act in grants and planning,
in standards and enforcement and in permits.

     The second section of the Act requires
the development of comprehensive programs
for preventing, reducing and eliminating
pollution, and further asks for research
and development aimed at eliminating
unnecessary water use.  In Section 208,
the statute directs the designation of
areawide institutions to plan, control and
maintain water quality and reduce pollution
from all sources through land use or other
methods.

     Construction grants for publicly owned
treatment works are made available to en-
courage full waste treatment management,
providing for:

     "(1)  the recycling of potential  sewage
pollutants through the production of agri-
culture, silviculture, and aquaculture
products, or any combination thereof;

     "(2)  the confined and contained
disposal of pollutants not recycled;
and
     "(3)  the reclamation of wastewater;
     "(4)  the ultimate disposal of sludge
in a manner that will not result in envi-
ronmental hazards."

     The grantees are encouraged to combine
with other facilities and utilize each
other's processes and wastes.   Facilities
are to be designed and operated to produce
revenues.

     These statutory provisions outline a
long-term program to reduce water use, re-
duce the generation of wastes  and establish
                                           655

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financially self-sustaining publicly
owned pollution control facilities.

     Congress recognized it was placing
demands on people, technology, the economy
and public and private institutions which,
ultimately, would determine the success of
the program.  There was uncertainty as to
whether the required technologies existed;
how the new law's implementation might
affect society, the economy, and the
environment; and how well the institutional
system would or could respond to this de-
manding new law.

     The Commission was established by
Section 315, to determine if a mid-course
correction was needed between 1972 and
1983, and to report its findings, con-
clusions and recommendations to the Congress
within three years from the law's enactment.

            COMMISSION CHARGE

     The Commission's charge is:

     To "...make a full and complete
investigation and study of all the tech-
nological aspects of achieving, and all
aspects of the total economic, social, and
environmental effects of achieving or not
achieving, the effluent limitations and
goals set forth for 1983 in Section
301(b)(2) of this Act."

     The Commission determined "that a
comprehensive study of the goals and
requirements for 1983 cannot be properly
undertaken without attention to the progress
made toward clean water by industries and
municipalities under the 1977 requirements."
It stated that it would "examine progress
toward the 'elimination of the discharge of
pollutants' as an indicator of what will
remain to be done after 1983."

     Because of the specific statutory
charge, the goal and effluent limitations
for 1983, and the impacts of their applica-
tion have remained the primary focus of the
Commission's attention.  In the time per-
mitted, no study could assess all the far-
reaching implications of each of the Act's
provisions.  Limitations of data, time and
resources, as well as evolving knowledge
and issues, restrict what can be done and
still meet deadlines.  The Commission has
completed a major undertaking and has
produced new and useful  information  for
the Congress.  The Commission  concludes
its assignment with the  knowledge  it has
both answered and generated questions.   Its
report contains the following  components:

Chapter I  -- An analysis of the capabili-
     ties and costs of technology  for
     achieving the effluent limitations
     required by 1977 and 1983, as well as
     a look at what remains to be  done after
     1983;

Chapter II  -- An assessment of the capabi-
     lity of the public  and private  sectors
     to apply the defined effluent limita-
     tions for 1977 and  1983, as well as
     those more stringent to protect water
     quality;

Chapter III -- An analysis of the  economic
     effect of the cost  of applying  the
     necessary technologies on both  a
     macroeconomic and microeconomic scale
     -- as well as the social effects of
     these changes;

Chapter IV -- A description of present water
     quality and environmental (water-
     based and related terrestrial)  condi-
     tions, and projections of anticipated
     change which may result from  imple-
     mentation of the Act.

Chapter V -- Identification of the effects
     in several selected regions of  the
     Nation; and

Chapter VI -- An assessment of the public
     and private response as the institu-
     tional segments finance,  implement,
     manage and enforce  the Nation's water
     pollution control program.

[The discussion which follows presents the
Commission staff's tentative summary of the
issues and findings.  Recommendations will
be formulated by the Commission as it
completes its deliberations and concludes
its work.]
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                 CAVEAT

     Commission studies performed by con-
tractors often provide a range of costs
and benefits for differing technologies,
conditions, or assumptions.  Complete and
reliable data were not always available
covering all questions the Commission and
contractors have analyzed; every effort is
made to explain methodologies and to qualify
estimates in the full text of the Commission
staff draft.  In the following summary,
reflecting this variability has been sac-
rificed for the sake of brevity.  There-
fore all cost and expenditure estimates and
quantified statements of effects should be
regarded as staff best professional judgment
rather than as exact measures of these items.
The staff recognizies that others might have
chosen other figures for different reasons.

                 CAVEAT

NOTE:  All dollar figures are stated in
June 1975 dollars.

I.  Progress Under 1977 Requirements

     Question:  How will progress toward
achieving the 1977 requirements affect the
timetables for "achieving or not achieving
the effluent limitations and goals set
forth for 1983"?

     Answer:  The effect is to delay
achievement of 1983 requirements and goals.
Slow progress toward achieving secondary
treatment by publicly owned treatment works
by July 1, 1977, will delay achievement of
"best practicable waste treatment technology
over the life of the works" by 1983.
Similarly, but to a lesser degree, indus-
tries and agriculture not achieving "best
practicable control technology currently
available" by July 1, 1977, will delay
achievement of "best available technology
economically achievable" by July 1, 1983.

     A.  Technological Aspects - 1977

     Publicly Owned Treatment Works - 1977

     Question:  Is secondary treatment for
publicly owned treatment works as defined
by the Administrator of the Environmental
Protection Agency technologically achie-
vable?

     Answer:  Yes.
     Question:  Will all publicly owned
treatment works achieve secondary treatment
by July 1, 1977?

     Answer:  No.

     Question:  When might all publicly
owned treatment works achieve secondary
treatment?

     Answer:  Achievement is dependent
primarily on Federal funding.*  For example,
it could be achieved in 11 years with 75
percent Federal funding of all eligible
construction categories except control and
treatment of separate storm sewer flows with
a total Federal outlay of $118.5 billion,
provided Federal appropriations and com-
mitments are made ranging from $2.6 billion
the first year to $15.6 billion in the last
two of the eleven years.  This pattern would
require radically accelerated processing of
all phases of grant administration and
treatment plant construction.  (Inflation
could increase the total to $184.4 billion.)
Achievement of some eligible categories
could be realized earlier depending upon
selective Federal funding.

     Industries - 1977

     Question:  Is "best practicable control
technology currently available" as defined
for industrial dischargers technologically
achievable?

     Answer:  Generally, yes, with the
exception of short term limits in some cases
and waste constituents or mixed wastewater
streams in others.

     Question:  Will all industrial dis-
chargers achieve best practicable control
technology currently available by July 1,
1977?

     Answer:  No.

     Question:  When might all industrial
dischargers achieve best practicable control
technology currently available?

     Answer:  Perhaps by 1980; industries
appear to be moving to achieve the 1977 re-
quirement at a rate that will assure achieve-
ment earlier than publicly owned treatment
works will achieve their 1977 requirements.

*H.R. 9560, Sec. 9, would allow time exten-
sion on a case-by-case basis but in no event
later than July 1, 1982.
                                           657

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         Capital Costs for 1977
                              Amount
Technology Costs        (Billions, 1975 $)
Iron & steel
Organic & miscellaneous
   chemicals
Inorganic chemicals
Petroleum refining
Pulp & paper
Metal finishing
Fruits and vegetables
Plastics & synthetics
Textiles
Steam electric power*
Feedlots**
All other industry***
            $2.91
             4.29

             0.52
             1.05
             2.64
            14.14
             0.44
             0.16
             0.54
               74*
               21**
            11.67***
                                 Capital Expenditures for 1977*
                         Economic Impact                     Amount
                         Expenditures*                  (Billions, 1975)
                         TOTAL   $44.31
           Iron & steel
           Organic and miscellaneous
              chemicals**
           Inorganic chemicals
           Petroleum refining
           Pulp & paper
           Metal finishing
           Fruits and vegetables
           Plastics and synthetics
           Textiles**
           Steam electric power***
           Feedlots****
           All other industry
                                                    TOTAL
                                                                                     $2.08
                                                                                       4.29**

                                                                                       0.81
                                                                                       0.83
                                                                                       2.33
                                                                                       9.13
                                                                                       0.16
                                                                                       0.21
                                                                                       0.54**
                                                                                       4.09***
                                                                                       0.80
                                                                                      11.28
                                                                                     $36.5
*Includes growth to 1977-
**Includes growth to 1977 and assumes
  coverage of all feedlots.  Estimated
  costs for EPA's most recent proposal
  (November 1975) would be $0.11 billion.
***See Table p. 10 for listing.
     B.  Economic Effects - 1977

     Publicly Owned Treatment Works
Categories
Amount
(Billions,
  1975 $)

    10.8
I. Secondary treatment
II.  Treatment more
    stringent than
    secondary             24.8
IIIA Correction (infil-
     tration/inflow)       6.9
11 IB Sewer rehabilitation  9.5
IVA Collector sewers      13.0
IVB Interceptor sewers    13.5
              Minimum
V. Combined
   sewers      $5.4
Calendar
  Year
Achieved

  1980


  1980

  1985
  1985
  1985
  1980
                              Maximum
   SUBTOTAL   $83.9

VI. Control of
    storm-
    waters    158.0

    TOTAL    $241.9
    79.6   88.4 1985

  $158.1 $166.9



   199.0  427.0

  $357.1 $593.9
                         *For plants in place as of June 1973;
                          no growth from that date is included.
                         **Does not have adjustments for closures.
                         ***Inc1udes all costs for existing plants
                            not entitled to exemption to meet
                            thermal requirements which become effec-
                            tive July 1, 1983.
                         ****Includes all categories of feedlots
                             with a limited number covered in each
                             category.
                                           658

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 C.  Environmental  Effects - 1977

     Question:   How far will the uniform
application  of  BPT to industrial dis-
chargers and secondary treatment to publicly
owned treatment works go toward achievement
of the interim  goal, a water quality
"wherever attainable" "which provides for
the protection  and propagation of  fish,
shellfish, and  wildlife and provides for
recreation in and on the water  ... by
July 1, 1983"?

     Answer:  Based on the analysis of the
Commission's 41 environmental sites,
application  of  the 1977 requirements will
restore a large portion of the nation's
                                   presently  polluted waters  to  a  level  of
                                   physical and chemical quality sufficient
                                   to provide for achievement of the interim
                                   goal.   The chief exceptions are caused by
                                   toxics,  pulse loads discharged  from
                                   point  and  nonpoint sources during and fol-
                                   lowing  storms and delays in actual  achieve-
                                   ment of the 1977 requirements.   Maintaining
                                   that level  of quality with continued  growth
                                   will depend upon timely and effective
                                   compliance with outstanding permits and the
                                   effective  application of more stringent
                                   limitations that may become necessary
                                   following  adoption of water quality stand-
                                   ards where the volume of pollutant dis-
                                   charges begins to produce  lower water
                                   quality.
                               DISSOLVED OXYGEN IMPROVEMENT
                      UNDER 4 LEVELS  OF POLLUTION CONTROL ABATEMENT
            DO Level
            Milligrams per liter
                    EDO
                                                                Minimum criterion during
;   / s
                                                                   seasonal low flow
              = anaerobic.
           10%           20%          30%          40%
             Percent of area with DO equal to or less than level shown
                                                                               50%
                           500            1000            1500           2000      2300

                            River miles with DO equal to or less than level shown
           *Based on projected improvements at 21 sites covering
            a total of 4600 river miles during seasonal low flow
            conditions.
           Source: Natl. Commission on Water Quality compiled
           from environmental contractor reports.
           February 1976
                                                    KEY ABATEMENT LEVELS
                                          EOD  	
                                          1983	
                                          1977 T 	
                                          1977 A	
                                          Present ——	
See Table IV-3
for explanation
of abatement
levels
                                             659

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II.  "Technological aspects of achieving";
     "economic, social and environmental
     effects_of achieving or not achieving,
     the effluent limitations and goals
     set forth for 1983. ..."

     A.  Technological Aspects - 1983

     Publicly Owned Treatment Works - 1983

     Question:  Does technology adequate to
achieve "best practicable waste treatment
technology over the life of the works"
for publicly owned treatment works exist?

     Answer:  Yes, since as defined by EPA
this technology is virtually the same as
that described by EPA for 1977.

     Question:  Will all publicly owned
treatment works achieve the "best practi-
cable waste treatment technology over the
life of the works" by July 1983?

     Answer:  No.  The primary reasons for
not achieving this requirement by the
scheduled date is an inadequate rate of
Federal funding, slow obligations of
existing funds and the time it takes for
construction of treatment works.

     Question:  When might all publicly
owned treatment works achieve best practi-
cable waste treatment technology over the
1ife of the works?

     Answer:  Depends primarily on level of
Federal funding.  Could be achieved in
eleven years, so long as there is little
technological difference between the 1977
and 1983 requirements and an adequate level
of Federal funding, commitment of the funds
and construction of plants is maintained.

     Industries - 1983

     Question:  Is defined "best available
technology economically achievable" for
industrial dischargers technologically
attainable?

     Answer:  Generally, yes, with the
exception of short term (24-hour) limita-
tions in some cases and those instances
where application of technologies must be
transferred from one industry to another
or have not been adequately demonstrated.
     Question:  Can industrial dischargers
attain best available technology economical-
ly achievable by July 1, 1983?

     Answer:  Depends upon date the 1977
requirements are actually met and resolution
of challenges to some effluent limitations
and permits.

     Question:  Should the deadline for
industry to achieve "best available techno-
logy economically achievable" remain
July 1, 1983?

     Answer:  No, and a "mid-course cor-
rection" appears indicated.

  Added Costs for 1983 Requirements
   Technology Costs
Iron & steel
Organic & misc. chemicals
Inorganic Chemicals
Petroleum refining
Pulp & paper
Metal finishing
Fruits & vegetables
Plastics & synthetics
Textiles
Steam electric power*
Feedlots**
All other industry
          TOTAL
      Amount
(Billions  1975  $)

    $0.95
     3.64
     0.25
     1.18
     0.80
    14.09
     0.16
     0.29
     0.30   Maximum
     2.03*
     0.49**
     6.38
T7T96
   $30.56   $36.49
*Includes growth to 1983.  Range depends on
 assumed exemptions.
**Includes growth to 1983.  Estimated costs
  for EPA's most recent proposal (November,
  1975) would be $0.04 billion.
                                           660

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     B.   Economic Effects - 1983
                         Added Expenditures for 1983 Requirements
           Economic Impact
             Expenditures

Iron & steel
Organic & miscellaneous chemicals
Inorganic chemicals
Petroleum refining
Pulp & paper
Metal finishing
Fruits & vegetables
Plastics & synthetics
Textiles
Steam electric power
Feedlots
All other industry
                         TOTAL
Existing Plants
     Amount
(Billions 1974 $)
  New Sources
 1973 to 1983
    Amount
(Billions 1975  $)

     $  .65
       2.25
        .35
        .29
        .73
       3.97**
        .05
        .09
        .28
        .99
        .23
      10.11
     $19.90
*Does not have adjustment for closures.
**Excludes captive shops included in
  machinery and mechanical  products, $8.30
  billion, under all other industry.
***Includes all categories of feedlots with
   a limited number covered in each category.
                                           661

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Table III.P.L
I NDJJ S T R Y
                     Preliminary Economic  Impact  Expenditure  Estimate
                                 (Millions  of  1975 dollars)
Indepth

Fruits & Vegetables
Inorganic
Organic
Misc. Chemicals
Iron and Steel
Metal Finishing-Job
           Captive
Petrol. Refining
Plastics & Synthetics
Pulp and Paper
Steam Electric
Textiles
Other

Ore Mining & Dressing
Coal Mining
Petrol. & Gas Ext.
Mineral Mining & Proc.
Meat Products & Rendering
Dairy  Products
Grain  Mills
Cane Sugar Processing
Beet Sugar
Canned & Preserved Seafood
Misc.  Food & Beverages
Timber Products
Furniture & Fixtures
Bldg.  Paper & Board
Paint  & Ink
Soap & Detergent
Phosphate Mfg.
Fertilizer Mfg.
Paving & Roofing
Rubber Processing
Leather Tanning
Glass  Mfg.
Cement Mfg.
Concrete, Gypsum, Plaster
Asbestos
Insult. Fiber
Ferroalloy Mfg.
Nonferrous Metals
^Machinery & Mech. Prod.
Transportation Ind.
Water  Supply
Auto & Other Laundries
Foundries
                  (continued)
BPT

(1977)
Annual
Capital O&M
155
805
3328
965
2080
1715
7418
829
209
2331
4089
537
24461
14
178
487
163
261
328
2275
142
33
117
989
88
5075
BAT

Capital
111
261
2990
653
546
780
7468
1184
286
757
1275
300
16611
(1983)
Annual
O&M
12
140
2242
228
203
168
1365
429
29
36
16
29
4897
19.75-83
NSPS
Capital
47
351
1873
380
647
3967
a
294
91
734
900
275
9559
611
1690
234
728
148
198
56
153
90
55
--
14
7
120
23
8
108
73
7
221
77
35
34
100
4
13
48
40
3900
866
1222
18
182
25
95
18
72
20
14
4
17
17
14
0
1
3
12
23
1
13
47
7
18
20
4
4
26
1
5
16
21
293
88
156
3
26
0
0
1069
0
179
66
9
165
69
105
5
25
0
0
0
1
26
68
4
48
39
57
9
0
9
0
10
31
3900
143
104
21
0
0
0
61
0
16
5
1
13
5
5
1
8
0
0
0
1
3
22
1
12
8
9
1
0
4
0
4
7
293
39
3
1
0
146
0
266
496
64
0
0
8
2
38
4
33
2
13
2
2
46
50
1
299
13
26
12
36
3
3
11
39
8295
137
28
8
0
                                            662

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Table III.P.L (continued

                                      INDUSTRY

                     Preliminary Economic Impact Expenditure Estimate
                                (Millions of 1975 dollars)
          Other

Fish Hatcheries
Structural Clay
Pottery
Steam Supply
Nonferrous Mills
Feedlots:
     Beef
     Hog
     Dairy

All Other Industries
In-depth Industries

          TOTAL                   36642    6234    22992     5423        19903


*Excludes Captive Metal Finishing

a  Included in Machinery and Mechanical Products

b  Includes all categories of feedlots with a limited number
   covered in each category.

National Commission on Water Quality
October 2, 1975
BPT

(1977)
Annual
Capital O&M
5
3
0
195
185
445
265
12181
24461
1
1
0
18
13
22
20
1159
5075
BAT

Capital
--
4
0
—
42
117
56
6381
16611
(1983)
Annual
O&M
--
3
0
—
0
0
0
526
4897
1975-83
NSPS
Capital
2
1
--
33
225b
--
--
10344
9559
                                            663

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     C.  Social Effects and Benefits -
         1977 and 1983

     Question:  Who is likely to bear the
adverse social impacts from the achievement
of the water quality requirements and goals?

     Answer:  Adverse impacts will fall most
heavily on the employees and owners (either
individual or corporate) of those industrial
plants closed as a result of the implementa-
tion of the 1977 and 1983 effluent limita-
tions.  Generally, small older businesses
will be adversely affected.  Employment
losses from plant closures, both direct
and indirect, could amount to over one-half
million jobs with full implementation of
BPT and BAT limitations.  Other categories
adversely impacted will be the moderate-
income family seeking to enter the housing
market for the first time, the low-income
resident who will bear a higher relative
cost of the local share of financing pol-
lution control facilities relative to his
income as a result of the shift from pro-
perty taxes to user fees.

     Question:  How many jobs will be
created by the implementation of P.L.
92-500?  What kind of jobs will they be and
how well distributed geographically and
demographically?

     Answer:  The major direct labor re-
quirement will be for construction workers
to build the plants and facilities.   Heav-
iest impacts will be in the area of publicly
owned treatment systems and sewers,  where
employment will reach a peak in 1977 of
296,000 new jobs and remain at over 100,000
through 1983*.  Overall, between 1975 and
1985, implementation of the Act will  create
a total of nearly one and a half million
man-years of work in the construction of
publicly owned waste treatment facilities.

     Question:  Who benefits?  Are there
identifiable publics that receive the
benefits derived from improved water
quality?
^Assumes BPT met by 1977 with expenditures
over three years, and BAT met by 1983 with
expenditures spread over six years; and
$60.9 billion for publicly owned treatment
works spread over eleven years.
     Answer:  Sports fishermen,  commercial
fishermen, seafood canners  and  processors
and those commercially associated  with
water-based recreational  pursuits  --  especi-
ally recreational boating -- will  be  major
beneficiaries of the Act. Property owners,
too, of riverside and shoreline  properties
will enjoy not only the  benefits of improved
water quality adjacent to their  property, but
also the increased value  of the  property as
well.

     Question: Are the benefits  from  the
achievement of the 1983  interim water
quality goal quantifiable?

     Answer: Yes. Improved  water quality will
provide the American public with greatly ex-
panded opportunities for water-based  recrea-
tion, sports fishing and  the commercial
harvesting of fish and shellfish.  Each of
these activities will result in directly
measurable benefits to individuals, segments
of society and to the economy in general.
There will be additional unquantifiable
benefits resulting from aesthetic  changes in
water bodies and water-related activities.

     Question:  Economically, what  will
these benefits amount to?

     Answer:  All quantified benefits, trans-
lated into dollar gains, may increase from an
estimated annual  rate of $3.4 billion in 1980,
to $5.2 billion in 1985, and $7.8  billion in
the year 2000, assuming gradual improvement
from the present to 1985 with increases in
benefits thereafter resulting solely from
population and economic growth.

     Question: Are these short-term benefits?

     Answer:  No. Assuming  the maintenance
of the water quality, these gains will con-
tinue to accrue into the future.   For swim-
ming alone,  the cumulative  benefits from
1985 to the year 2000 could reach  between
$16 and $17 billion, and annual quantifi-
able benefits for all activities could
reach $6.4 billion by the year 2000.

     Question:  Are there unquantifiable
benefit associated with the achievement of
the 1983 interim water quality goal?
                                           664

-------
     Answer:   Yes, two important kinds:
(1)  those not fully identified yet, such as
health effects, where quantification now is
impossible;  and (2) those associated with
non-contact  related experiences.

II.   D.   Environmental Effects - 1983

     Question:   Do incremental improvements
in water quality characteristics associa-
ted with achievement of the 1983 effluent
limitations  contribute significantly to
the realization of the 1983 goal?

     Answer:   In most cases, the gains are
projected to be less than those indicated
for achievement of the 1977 requirements.

III.  Technological Aspects and Economic
      Effects of 1977 and 1983 Requirements
      Applied to Agriculture

      Agriculture - 1977 and 1983

      Question:  Are agricultural point
sources of pollutants amenable to the
technological concepts of BPT and BAT?

      Answer:  Some are, such as feedlots.
Others, such as irrigation return flows,
present unique and widely variable problems
when attempting to apply effluent limita-
tions requirements of P.L. 92-500.

      Question:  What is being done to
implement BPT for irrigation return flows?

      Answer:  Since EPA has defined the
1977 requirement as monitoring the quantity
and quality of intake water supply and
irrigation return flows, BPT as so far
defined, is  technologically achievable.
Complex and  widely varying systems by which
excess water applied for irrigation reaches
surface and  ground waters in the vicinity
of its application, do present even monitor-
ing problems, however.  Known control tech-
nologies currently available are not so
well developed as to assure their universal
practicable  application with predictable
results.

      Question:  Is "best available techno-
logy economically achievable" to control
pollutants in irrigation return flows
technologically attainable by July 1, 1983?
     Answer:  No, simply because no univers-
ally applicable or effective technology has
been developed which can be applied with
reasonably predictable results for all
geographic areas.

     Question:  Should statutory provisions
intended to control pollution from irrigation
return flows remain a part of P.L. 92-500?

     Answer:  Yes, but they should be so
formulated and designed as to recognize the
variety of polluting effects, the unique
institutional structure of irrigated agri-
culture, the wide geographical differences
in irrigation objectives and practices and
the state-of-the-art for control practices
and measures for reducing pollutants from
irrigated agriculture.

IV.  Institutional Factors Influencing
     "Technological Aspects of Achieving"
     arid "Economic, Social, and Environ-
     mental Effects of Achieving or Not
     Achieving, the Effluent Limitations
     and Goals Set Forth for 1983	"

     Institutional Factors   1977 and 1983

     Question:  How has the response of the
national institutional structure for water
pollution control -- Federal, State, inter-
state, regional and local governments,
industrial and agricultural dischargers and
all interested groups -- affected achieving
or not achieving by the stated deadlines
all that is required to meet the require-
ments and goals of P.L. 92-500?

     Answer:  Individually and collectively,
their response has contributed to the time
required to achieve results under P.L. 92-
500.  Unfortunately, the interrelationships
have too often been adversary rather than
cooperative in nature.

     Question:  What are the implications of
the resultant delays in meeting deadlines
or implementing various statutory directives?

     Answer:  The obvious implication is
that the time schedule for accomplishment
of some requirements and goals of the Act
is out of phase.  The first major deadline
-- installation by dischargers of Phase  I
wastewater treatment technologies by
July 1, 1977 -- will not be met by all
                                           665

-------
dischargers, and the series of delays
which have occurred within the institu-
tional structure and the slow flow of grant
funds share major responsibility.  This
fact requires consideration of alteration
in the present time schedule for accomplish-
ment to coincide more closely with the
realities of current circumstances and
available funding as well as the limitations
inherent in the intergovernmental process
and the interactions between these
governments and the various affected and
participating "publics".

     Question:  Where in the program struc-
ture are the delays most seriously mani-
fested, and what do they reveal about the
fundamental implementation strategy of the
Act?

     Answer:  The strategy of the Act is
predicated on the proposition that 75
percent Federal construction grant as-
sistance for publicly owned treatment works,
coupled with strong centralized national
initiatives for regulation and enforcement
structured within a framework of compre-
hensive state and local planning, will
produce the most expeditious, effective
and sensitive application of resources and
manpower to the accomplishment of national
water quality objectives.  In the first
three years a divergence has evolved
between the proposition and its realiza-
tion.  Delays in issuance of guidelines,
effluent limitations, and regulations,
delays in the obligation and outlay of
Federal funds for construction grants,
delays and variations in the issuance of
the NPDES permits for municipal, industrial
and agricultural dischargers and the fact
that mandated planning requirements are
seriously out of synchronization with the
construction grants and permit phases, all
contribute to uncertainty as to the validity
of the essential proposition.  Experience
with  implementation to date can neither
effectively discredit nor irrefutably
sustain the proposition.  Experience can,
however, identify the points in the imple-
mentation process where the delays have
been most pronounced and make some observa-
tions, based on performance thus far, about
the basic structure of institutional co-
operation vital to the Act's fair and ef-
fective implementation.
     A.  Regulation

     Question:  Has implementation progres-
sed sufficiently to identify any basic
problems with the regulatory strategy con-
templated in P.L. 92-500?

     Answer:  While there are still a number
of uncertainties about the implementation
of the regulatory scheme, the conduct of
two activities in the regulatory strategy
can jeopardize the effective implementation
of the Act.   One is the development and
promulgation of effluent limitations which
are being aggressively contested by industry
in over 250 legal challenges.  The other is
the capability of the Federal, state and
local  regulatory and administrative agencies
to develop useful information systems for
monitoring and reporting compliance with the
Act's various program components.

     B.  Financing

     Question:  Has the flow of Federal
construction grant funds to the states for
publicly owned treatment works impacted the
timely achievement of the 1983 requirements
and the interim goal?

     Answer:  Yes.

     C.  Planning

     Question:  Has implementation of the
planning provisions of the Act progressed
commensurate with the planning policy
objectives articulated in Sec. 101(a)(5) --
"that areawide waste treatment management
planning processes be developed and imple-
mented to assure adequate control of sources
of pollutants in each state"?

     Answer:  No.  The planning process is
already out of sequence with the imple-
mentation strategy.

     D.  Public Participation

     Question:  Has the experience with
public participation in water pollution
control programs differed significantly
under P.L.  92-500 from prior experience?

     Answer:  No.  Even though the Act
mandated an unprecedented public role, there
is no empirical evidence to  suggest that  the
actual influence of the citizen  on the
decision-making process has  effectively
increased.
                                           666

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V.   What Vim Remain to be Done After 1983

    Elimination of the Discharge of
    Pollutants - the 1985 Goal

    Question:  Assuming achievement of the
1977 and 1983 requirements for publicly
owned treatment works and agricultural and
industrial dischargers at some future date
later than 1983, what major pollutant
sources will continue to prevent realization
of the interim and ultimate goals?

    Answer:  Any point source (such as urban
runoff in separate storm sewers) not
adequately controlled with the 1977 and
1983 requirements or any nonpoint source
(such as urban runoff from other than
combined sanitary and storm and separate
storm sewers and agricultural or general
land runoff) contributing pollutants to the
nation's waters can prevent achievement of
the water quality goals of the Act.  The
effect of these source contributions in some
site specific areas of the country will
prevent achievement of the water quality
goals of the Act and may, in some cases,
overwhelm improvements from point source
control.  To the extent that publicly owned
treatment works, industrial and agricultural
dischargers have not achieved elimination of
the discharge of pollutants, they, too,
would be major contributors.

    Question:  Are there technologies avail-
able now, or that might reasonably be expec-
ted to become available within the next 10
years, that could achieve the elimination
of "the discharge of pollutants into the
navigable waters"?

    Answer:  Yes. However, in most cases the
costs of these technologies are such that,
however the technologies might be applied to
point source discharges, their installation
would be prohibitively expensive, and the
economic and social effect would be too
severe to be absorbed within the foreseeable
future; further, predictable environmental
effects, using present analytical techniques
and methodologies, would appear to be
minimal, particularly in the absence of
adequate control of nonpoint sources of
pollutants in some places.
     Question:  Does the goal of the elimi-
nation of "the discharge of pollutants into
the navigable waters" have value as a guide
to policymakers?

     Answer:  Yes.  Wastes generated by pro-
jected population increases and continued
economic growth, if discharged to the
nation's waters, can soon minimize the
effect of improvements in receiving water
quality realized through achievement of the
1977 and 1983 requirements of the Act applied
to point source discharges.  If new sources
of pollutants -- new industrial plants,
agricultural activities and increased dis-
charges from publicly owned treatment works
-- install "the best available demonstrated
control technology, processes, operating
methods or other alternatives, including,
where practicable, a standard permitting
no discharge of pollutants" [Sec 306(a)(l)],
and if existing water quality standards are
regularly reviewed and appropriate waste
load allocations timely made, this action
may assure that growth does not negate the
improvements achieved by point source
effluent limitations as the program envi-
sioned by P.L. 92-500 is implemented.

     Question:  Is progress being made to-
ward the "objective of this act ... to
restore and maintain the chemical, physical,
and biological integrity of the nation's
waters"?

     Answer:  Yes, although progress to date
attributable to P.L. 92-500 is minimal, since
results from its implementation are only now
beginning to be realized.

     Question:  Can this "objective" serve as
a guide to policy-makers for their actions?

     Answer: Not with much certainty or
specificity. Even the experts cannot agree
upon a full statement of the objective's
meaning. "Restore" obviously means returning
to some prior condition; restoring "physical"
integrity could mean eliminating man-made
changes in the nation's waterways so that
sediment loads and  temperatures  would be as
they were before man's perturbations of the
land; restoring "chemical" and "biological"
integrity would require knowing these con-
ditions of the nation's waters at some
historical point in time with a degree of
accuracy not possible from existing historical
data.  Man has consistently adjusted, or
attempted to alter, the "biology" of the
                                           667

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nation's waters to suit his perceived
needs.  These adjustments or alterations
would have to be eliminated in any literal
application of the objective -- often to
man's discomfort, if not to the detriment
of his well-being or health.
                                          668

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                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
 1. REPORT NO.
 EPA-600/9-76-023
                                                            3. RECIPIENT'S ACCESSION NO.
 4. TITLE AND SUBTITLE

 PROCEEDINGS,  FOURTH UNITED STATES/JAPAN CONFERENCE
 ON SEWAGE TREATMENT TECHNOLOGY
             5. REPORT DATE
              October 1976 (issuing  date)
             6. PERFORMING ORGANIZATION CODE
 7. AUTHOR(S)
                                                            8. PERFORMING ORGANIZATION REPORT NO.
 9. PERFORMING ORGANIZATION NAME AND ADDRESS
 U. S. Environmental Protection Agency*
             10. PROGRAM ELEMENT NO.

                 IRW 103
                                                            11. CONTRACT/GRANT NO.
 12. SPONSORING AGENCY NAME AND ADDRESS
 U. S. Environmental Protection Agency* - Cin., OH
             13. TYPE OF REPORT AND PERIOD COVERED
              Proceedings - Oct. 23-28.  197
                                                            14. SPONSORING AGENCY CODE

                                                              EPA/600/14
 15.SUPPLEMENTARY NOTES*Symposium sponsored by Office of Int 1 Activities,  Office of Water
 & Hazardous Materials  (Wash.,D.C. 20460), &  Office of Research & Development (Cinti.OH
 45268  &  Wash.,D.C. 20460).  This volume prepared  & published by Office of Research &
 16. ABSTRACT
                                  Development,  Cincinnati, Ohio 45268.
      As part  of  joint interests  in  environmental matters  between the United  States
 and Japan a Conference on Sewage Treatment Technology  is  held at intervals of  about
 18 months.  This publication contains papers from the  Japanese group and from  the
 American side that were presented at  the Fourth Conference.   Subject matter  covered
 includes sludge  treatment and disposal,  automation and instrumentation, advanced
 waste treatment, planning and management of wastewaters,  storm and combined  overflows,
 and industrial waste treatment.   The  publication is unique in that it presents,  in
 English, comprehensive information  on wastewater treatment and research being
 conducted in  Japan.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
                                              b.IDENTIFIERS/OPEN ENDED TERMS
                           c. COS AT I Field/Group
 Sewage treatment,  Sludge disposal,
 Industrial waste  treatment,
 Waste disposal
 Water pollution control
  13B
 8. DISTRIBUTION STATEMENT
 To  Public
19. SECURITY CLASS (This Report)'
  unclassified
21. NO. OF PAGES
  681
                                              20. SECURITY CLASS (This page}
                                                unclassified
                                                                         22. PRICE
EPA Form 2220-1 (9-73)
                                             669
                  *USGPO: 1977-757-056/5496 Region 5-1

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