EPA-670/9-75-005
MAY 1975
                     PROCEEDINGS
      THIRD U.S.-JAPAN CONFERENCE ON
      SEWAGE TREATMENT TECHNOLOGY
                   February 12-16, 1974
                       TOKYO,  JAPAN


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                                    EPA-670/9-75-005
                                            May  1975
               THIRD

            U.S. - JAPAN

           CONFERENCE  ON

    SEWAGE TREATMENT TECHNOLOGY

            PROCEEDINGS
       February 12-16, 1974
           Tokyo, Japan
  OFFICE OF INTERNATIONAL ACTIVITIES
  OFFICE OF RESEARCH AND DEVELOPMENT
OFFICE OF WATER AND HAZARDOUS MATERIALS

 U.S. ENVIRONMENTAL PROTECTION AGENCY
           CINCINNATI, OHIO

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                 REVIEW NOTICE
       This publication has been reviewed by
the U.S. Environmental Protection Agency and
approved for publication.   Approval does not
signify that the contents  necessarily reflect
the views of the Agency nor does the mention
of trade names or commercial products constitute
endorsement or recommendation for use.

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                 FOREWORD
     The United States and Japan share a common
concern for the protection of man's environment.
Both nations have recognized that their highly
developed technological talents should be turned
to the solution of environmental problems which
confront us today.  In the past they have made
important advances, both individually and in
cooperation with others, to preserve and enhance
the quality of life.

     The advantages which accrue from cooperative
effort on problems of mutual concern are undeniable.
Building on two earlier successful meetings, the
Third U.S./Japan Conference on Sewage Treatment
Technology, held in Japan in 1974, is a recent
example of effective cooperation for mutual benefit.
These Proceedings will be of real value to future
efforts in the field.

     We look forward tq,_siinilar productive cooperation
in the future.                             -
                      ('-"" \ I    1
                           \L\ ii\JT (
                      Rusdell IE. Train
                       Adnlinistrator
Washington, D.C.
April, 1975

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                   CONTENTS










FOREWORD                                     iii







JAPANESE DELEGATION                            v







U.S. DELEGATION                               vi







JOINT COMMUNIQUE                               1







JAPANESE AGENDA                                4







JAPANESE PAPERS





     OFFICIAL CONFERENCE                       5







AMERICAN AGENDA                              189








AMERICAN PAPERS





     OFFICIAL CONFERENCE                     190
                       IV

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                            JAPANESE DELEGATION
         THIRD US/JAPAN CONFERENCE ON SEWAGE TREATMENT TECHNOLOGY
Dr. Takeshi Kubo
Mr. Katsuto Inomae
Dr. Mamoru Kashiwaya
Mr. Kenjiro Saito
Mr. Shigeru Ando
Mr. Katsumi Yamamura
Mr. Kenichi Hanada
Dr. Shoichi Nanbu
Dr. Akinori Sugiki
Mr. Satoru Toyama
Mr. Masayuki Sato
Mr. Seiichi Yasuda
Mr. Hideo Fuji!
Head of Delegation
Director General
Department of Sewerage & Sewage Purification
Ministry of Construction

Head
Sewage Works Division
Department of Sewerage & Sewage Purification
Ministry of Construction

Chief
Water Quality Section
Public Works Research Institute
Ministry of Construction

Chief
Sewage Works Section
Public Works Research Institute
Ministry of Construction

Chief
Advanced Waste Treatment Section
Public Works Research Institute
Ministry of Construction

Head
Water Quality Control Division
Water Quality Bureau
Environmental Agency

Head
Water Pollution Control Division
National Research Institute for Pollution
and Resources
Ministry of Commerce and Industry

Head
Sanitary Engineering Division
National Public Health Institute
Ministry of Health and Welfare

Head
Research and Technology Development Division
National Sewage Works Corporation

Head
Engineering Division
National Sewage Works Corporation

Director
Sewage Works Bureau
Yokohama City Office

Director
Sewage Works Bureau
Kyoto City Office

Head
Technology Development Division
Sewage Works Bureau
Tokyo Metropolitan Government

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                             U.S. DELEGATION

        THIRD U.S./JAPAN CONFERENCE ON SEWAGE TREATMENT TECHNOLOGY
Francis M. Middleton, Team Leader
Jesse M. Cohen
Edwin F. Earth
Dr. Joseph B. Farrell
Francis J. Condon
Charles H. Sutfin
Andrew M. Caraker
Bart Lynam
Richard Whittington
Deputy Director
National Environmental Research Center
Environmental Protection Agency
Cincinnati, Ohio  45268

Chief, Physical-Chemical Treatment Section
Advanced Waste Treatment Research Laboratory
National Environmental Research Center
Environmental Protection Agency
Cincinnati, Ohio 45268

Chief, Biological Treatment Section
Advanced Waste Treatment Research Laboratory
National Environmental Research Center
Environmental Protection Agency
Cincinnati, Ohio 45268

Chief, Ultimate Disposal Section
Advanced Waste Treatment Research Laboratory
National Environmental Research Center
Environmental Protection Agency
Cincinnati, Ohio 45268

Staff Chemical Engineer
Municipal Pollution Control Division
Office of Research & Development
Environmental Protection Agency
Washington, D.C. 20460

Chief, Process Technology Branch
Municipal Wastewater Systems Division
Office of Water Programs
Environmental Protection Agency
Washington, D. C. 20460

Coordinator for Japanese Affairs
Office of International Activities
Environmental Protection Agency
Washington, D.C. 20460

Superintendent, Metropolitan Sanitary
District of Greater Chicago
100 East Erie Street
Chicago, Illinois 60611

Deputy Director, Texas Water Quality Board
3101 Highland Terrace, W.
Austin, Texas 78731
                                       VI

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                        JOINT COMMUNIQUE

                  THIRD U.S./JAPAN CONFERENCE

                             ON

                  SEWAGE TREATMENT TECHNOLOGY
                                                Tokyo, Japan
                                           February 16, 1974
1.     The Third U.S./Japan Conference on Sewage Treatment

Technology was held in Tokyo from February 12-16, 1974 by

mutual agreement between Mr. Russell E. Train, Administrator

of the U.S. Environmental Protection Agency (EPA) and Mr. Takao

Kameoka, Ministry of Construction.

2.     The U.S. Delegation headed by Mr. Francis M. Middleton,

Deputy Director of The National Environmental Research Center

(NERC), Cincinnati, Ohio, EPA was accompanied by seven repre-

sentatives from the U.S.  EPA, state and local governments.

3.     The Japanese delegation headed by Dr. Takeshi Kubo,

Director General, Department of Sewerage and Sewage Purification,

Ministry of Construction, was composed of eight National officials,

three local government officials, and two representatives from the

Japan Sewage Works Corporation.

4.     Prior to the Conference the U.S. delegates visited Saitama

Prefecture Arakawa Sewage Treatment Plant, Tokyo Metropolitan Government

Ukima Works and Ochiai Works, Yokohama City Torihama Industrial Waste

Treatment Works, Yokosuka City Shitamachi Sewage Treatment Plant,

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Zushi City Water Pollution Control Center, Fujisawa City South Sewage




Treatment Plant, Atami City Nishikigaura Sewage Treatment Plant, Kyoto




City Toba Sewage Treatment Plant and Kisshoin Sewage Treatment Plant,




Nara Prefecture Yamato River Purification Center and advanced waste




treatment pilot plants at Yokosuka and Kyoto which were conducted by the




Ministry of Construction.




5.     Each field visit involved the subject matter to be discussed during




the Conference.




6.     The U.S./Japan Conference on Sewage Treatment Technology grew out of




the Second U.S./Japan Ministerial Conference on Environmental Pollution held




at Washington, D.C. in June, 1971 between Chairman Russell E. Train, then




Head of the Council on Environmental Quality and then Japanese Minister




Sadanori Yamanaka.  The First Conference was held at Tokyo, Japan in 1971




and the Second Conference was held at Washington, D.C. in 1972.




7.     Principal topics of the Third Conference were Federal Water Pollution




Control Act Amendments of 1972, sludge treatment and disposal, combined muni-




cipal and industrial waste treatment and advanced waste treatment technology.




During the Conference the presentations were followed by vigorous discussions




from both sides.




8.     In addition to the Conference, the Municipal Design Seminars were




opened to about two hundred members of the Japan Sewage Works Association




on the subjects of physical-chemical treatment technology, pure oxygen




activated sludge technology, upgrading of existing plants, and combined




sewer and stormwater technology.




9.     A video tape concerning research on environmental pollution at the




Robert A.  Taft Center, NERC, EPA, Cincinnati, Ohio was narrated in Japanese

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by Mr. Tokuji Annaka, research engineer, Public Works Research Institute,




Ministry of Construction.  Mr. Annaka is spending one year in Cincinnati




by an exchange program of technical personnel between two countries in a




follow-up of conclusions reached at the Second Conference held at Washington,




D.C. in 1972.




10.    The Conference was successful and fruitful in the exchange of knowledge




and experience with each country.  Future emphasis will be placed upon closer




exchange of experts and information between the two countries.




       A progress report of these three Conferences since 1971 will be pre-




sented by both sides for the coming U.S./Japan Ministerial Conference on




Environmental Pollution.




11.    The delegations agreed to explore and identify research projects,




which might be undertaken jointly by both U.S. and Japanese experts, and




also to look for the possibility of attendance of officials from Asian




countries to the future conferences.

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                                AGENDA


                        JAPANESE PRESENTATIONS



TUESDAY, FEBRUARY 12:

       JAPANESE SIDE VIEWS ON U.S. FEDERAL WATER POLLUTION
       CONTROL ACT AMENDMENTS OF 1972

WEDNESDAY, FEBRUARY 13:

       HEAT TREATMENT OF SEWAGE SLUDGE

       COMBINED TREATMENT OF MUNICIPAL AND INDUSTRIAL WASTEWATER


THURSDAY, FEBRUARY 14:

       STUDIES ON ADVANCED WASTE TREATMENT

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                                     Third US/JAPAN Conference
JAPANESE  SIDE VIEWS ON THE FEDERAL WATER
POLLUTION CONTROL  ACT  AMENDMENTS OF  1972
  WATER QUALITY  STANDARDS, EFFLUENT STANDARDS

                     presented by
                   Katsumi Yamamura
            Head, Water Quality Control Division,
                  Water Quality Bureau,
                   Environment Agency
  GRANTS FOR CONSTRUCTION OF TREATMENT WORKS,
         RESEARCH AND RELATED PROGRAMS
                     presented by
                     Takeshi Kubo
     Director, Department of Sewerage  & Sewage Purification,
                     City Bureau,
                 Ministry of Construction
                 February 12-16, 1974
               Ministry of Construction
                 Japanese Government

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                           CONTENTS


                                                                  Page
1.   Water Quality Standards,  Effluent  Standards  ...............

2.   Grants -for Construction of  Treatment Works,  Research  and
     Related Programs ..........................................

 2.1   Introduction ............................................     "

 2.2   Target Dates ............................................    10

 2.3   State Grants for Construction of Treatment Works  ........    10

 2.4   Reactions for guidelines  from professional engineers  ....    H

 2.5   Secondary Treatment Information  .........................    12

 2.6   Information on Alternative  Waste Treatment Management  ...    12

 2 . 7   Infiltration/Inflow .....................................    13

 2.8   Allotment of Federal Grants for  Construction  of Treatment
       Works ....................................... : ...........    ^

 2 . 9   Public Participation ....................................    1^

 2.10  Cost-Effective Analysis .................................    15

 2.11  Pretreatment Standards ..................................    15

 2.12  User Charges ..... .......................................    16

 2.13  Industrial Cost Recovery  ................................    IT

 2.14  Consideration on Reclaiming or Recycling of Water ......     18

 2 . 15  Planning of Storage for Water ..........................     18

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1.    Water Quality Standards, Effluent Standards

     As the contents and intentions of the Federal Water Pollution Control
Act of 1972 were made clear through the Guidelines and other informations
                                                 x
recently issued, we, as Government officials responsible for water pollu-
tion control, highly appreciate such informations and the Act itself as
good references for considering the measures to combat water pollution
such as establishment of regulatory standards and as basic informations
for reviewing the measures already taken.
     First, we feel that the FWPCA of 1972, which most comprehensively
provides for the policy to protect and improve water quality, is more
functional than the statutory system in Japan, composed of several laws
i.e. the Basic Law for Environmental Pollution Control which is the
basic law for pollution control policy in general and provides for the
establishment of Water Quality Standards, and the Water Pllution Control
Law which provides for various regulatory measures and other laws to
carry out pollution control projects including construction of sewerage.
     The second point I want to say is on Water Quality Standards.
The Water Quality Standards under the FWPCA of 1972 are to be established
to attain a very high quality of the environment so as to protect fishes
and other aquatic living organisms and their culture, and to maintain
the natural beauty and the amenity for peaple's recreation activities.
We would highly appreciate such intensive water pollution control policy
when considering its difficulty in attaining such high quality in any
water bodies which are already polluted to some extent including closed
waters such as harbors around industrial zones.
     The third point is on effluent standards.
I think that you have made great change in ways of thinking and those
provisions on best practicable or best available technology are to be
applied in all bodies of water.  This would give great influence on
water management policy in Japan.
     According to the informations already published, the effluent
standards have been set as maximum emission units e.g. maximum COD
emission amount per unit raw material in cases when best practicable

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 or best available  technologies  are  adopted.  We have  not  been able  to
 examine the effluent  standards  in detail  but we have  found  that  some of
 them are very stringent.  We  think  that,  in order  to  establish such
 standards,  you had to consider  current  effluent treatment technologies,
 differences in manufacturing  processes, possible effects  on production
 costs,  etc.,  and we highly  appreciate the efforts  you have  made.

      I  would like  to  ask  you  a  few  questions on the FWPCA of 1972,  the
 Guidelines  and related matters.

 (l)  Any State Governor has to  consult  with the Administrator of  EPA
 when he wants to work out a plan for pollution control, development and
 use of  water resouces (including restoration, conservation  and protectioi
 of them) with the  view to preventing water pollution.  I  want to  know
 the methods and procedures  of the consultation and environmental  impact
 assessment  between State  Governor and the Administrator.

 (2)  You have established to  effluent standards as emission amount  of
 pollutant per unit raw materials.   I think that continuous  manitoring
 systems of  quality and quantity of  effluent and of consumption of raw
 materials should be established.  How do  you carry out such monitoring?
     What  like are the cases when the establishment of least water
 quality  standards is considered impossible because of natural  conditions
 of water,  man-made pollution and special purpose of use of water?   I
 think that the acidic waters caused by mines is one of those cases.
 How do you establish water quality standards in this case?  And do  you
 carry out  any measures to improve the quality of such acidic waters?

 (4)  Some  bottom deposits may give bad influence on fishes, ecosystem
 and water  quality.  Organic deposits will influence on eutrophication.
     For example, mercury in fishes of Minamata Bay is considered to be
 caused by  contaminated deposits.  In order to combat pollution by
 mercury and its compounds, we established the Provisional Standards for
 Removing Bottom Deposits Containing mercury on June 30, 1973-  Do you
have any intention to establish standards for removing bottom deposits
and to enforce them?

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2.   Grants for Construction of Treatment Works, Research and Related
     Programs

2.1   Introduction

     Environmental pollution control has teen one of the important policies
recently in Japan especially for these several years and it is further
recognized that the policy of the environmental pollution control shall
be placed on a top priority among various national policies from now on.
Because, initially the pollution problem was attacked on a fragmentary
basis with various local governmental units coped with the independent
countermeasure for special types of pollutant, but the environmental prob-
lems, particularly water pollution problems relating to rivers, lakes and
coastal waters are accused by the public not only in the industrial area
of the large cities, but also in the rural area of all over Japan, and
so the public has become more aware of water pollution and its attendant
environmentally degrading problems in such a way of the fishermen's
union's demonstration against pollution in various part of Japan.  Under
these circumstances the positive protective actions have been seriously
demanded with increasingly periodicity.
     Japanese Government has been trying to establish powerful legislation
on pollution control and also to promote the countermeasure against water
pollution prevention such as sewage treatment construction planning.
This is my understanding that the Federal Water Pollution Control Act
Amendments of 1972 (the Act) is a very comprehensive and complex law that
addresses all types of water pollution, and so far in Japan we could not
go through such a experience on its comprehensiveness and its ambitious
national goals.  In the beginning of the Act the national goals are
declared in taking up a positive attitude.  The ultimate goal is to
eliminate the discharge of pollutants into the navigable waters of the
United States by 1985 and the interium goal is to achieve the water
quality by July 1, 1983 which provides for the protection and propaga-
tion of fish, shelfish and wildlife and provides for recreation in and
on the United States waters.  Further, the national policy is that the
discharge of toxic pollutants in toxic amounts be prohibited.  The

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 concrete  measure  and  the  definite procedure  to attain  the  goal  can  be
 realized  through  the  regulations and guidelines pursuant to  each  section
 of the  Act.
      It is understandable that  the regulations establish the terms  of
 requirements  for  each specific  piece of  the  Act and  the guidelines  ex-
 plain,  amplify  in detail,  and provide guidance to  supplement the  regula-
 tions,  and in these connections the regulations are  formal documents that
 provide the legal framework for the implementation of  the  Act and on the
 other hand the  guidelines are explanatory and assist in the  understanding
 of the  regulations.   I have gotten through with reading some regulations
 and guidelines  and I  would like to present the Japanese side views  and
 to make some  comments on  the Act, regulations and  guidelines.

 2.2  Target  Dates

      In order to  achieve  the ultimate national goal  you have only ten
 years more.   With full implementation of the Act including target dates
 for the use of  "best  practicable" technology subsquently "best  available"
 technology, and finally zero discharge of pollutants,  and  in these  con-
 nections  you  shall have to carry out the extraordinarily large  waste
 treatment works program.   It seems to me that it takes time  to  explore
 to make the most  reasonable planning and also designing with waste
 treatment facilities  from view  point of engineering, and as  might be
 expected  in such  a development, by now it is highly  doubtful that any
 local government  would meet its responsibility to  control  water pollution
 unless  the maximum authorized federal grant is provided, and the  18
 billion dollars federal grant program will be increasing due to construc-
 tion cost  rising,  and also there must be many difficulties to cope  with
 the time  limitation of the Act  for small communities and small  industries.
 From these points  of view  I am  obliged to acknowledge  that it will  be
 too short  to attain the target  dates for the ambitious national goals.

 2.3   State Grants for Construction of Treatment Works

     Before enactment of 1972 Amendments Act, the  program  was aimed at
providing an incentive for State Governments and local municipalities
                                    10

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and offered 10$ bonus federal grant in the case of combination of state
grant program and of regional waste treatment plant construction.  It
seems that such an incentive policy would be quite effective to promote
construction program with each financially sharing basis among Federal,
State and local municipality.  The national goals of the Act should be
the mutual goals of all concenrned with protection of U.S. Nation's
waters and in order to achieve the national goals it should be absolutely
necessary to keep a coordinate effort with each other among EPA, State
agencies, municipalities, design engineers, and industries.  In order
to keep such a partnership some kinds of incentive with each other would
be desirable.  The current program promises seventy-five percentage
federal grant of the construction cost of sewage treatment plants and
sewers for publicly owned facilities of any size and in this case there
is no incentive between EPA and state agencies.  I would say that collabora-
tion and cooperation should be maintained at the federal, state and regional
level.  Through the experience in the past Act is there any bad effects
in such an incentive way of federal grant system between federal and
states.

2.4   Reactions for Guidelines from Professional Engineers

     It seems that the regulations and guidelines establish a very power-
ful frame work for the purpose of establishing minimum requirements to be
followed by all planners and designers of municipal water pollution
control facilities, and I can imagine that there must be the tendency
of guidelines to be used as standards.  The objective of the Act is to
restore and maintain the chemical, physical and biological integrity of
the Nation's waters and this tendency should not cause the regulations
and the guidelines to become too confining, because this tendency could
stifle the creativity of the professional designers.  I think that
standardization on design criteria of facilities sometimes will give a
bad effect to creative improvement from view ponts of engineering.  Do
you have any reactions or arguments from the professional designer's
field on the matters of standardization caused by establishing the
regulations and guidelines of the Act?
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 2.5    Secondary Treatment Information

     Pursuant  to  section 304  (d)  (l) the information, in terms of  the
 parameters  of  biochemical oxygen  demand, suspended solids, fecal coliform
 bacteria  and pH on the degree of  effluent reduction attainable through
 the  application of• secondary  treatment.  Terms  '1-week' and  '1-month' as
 used in effleunt  samples are  expressed in a period of seven  consecutive
 days and  thirty consecutive days.  It is reasonable in this  way to have
 the  parameters of BOD, SS and fecal coliform bacteria.  It is understand-
 able that in the  case of comb'ined sewer system during wet weather  require-
 ments  should be made case by  case, but it seems to me that there should
 be some guidelines to make the decision of the attainable percentage
 removal level  in  combined sewer during wet weather.  In 'most of large
 cities in Japan the combined  system has been taken and many  storm-overflows
 do exist  exactly  on sewers.   In these cases it is not so practicable to
 decide the  requirements even  in case by case.  I understand  in the regula-
 tions  that  when industrial wastes discharge into publicly owned treatment
 works, effluent standard can  be adjus'ted upwards to only those cases in
 which  the flow or loading from an industrial category exceeds 10 percent
 of the design  flow or loading of  the treatment works.  Actually the per-
 centage of  the flow or loading of industrial waste into publicly owned
 treatment works may vary from time to time, and this means that the
 effluent  standards from the corresponding publicly owned treatment works
 may  vary  from  time to time being adjusted proportionally-  Who is  taking
 responsibility to decide the effluent standards for such a case by case
 such as combind sewer and industrial waste problem?  I shall be much
 obliged if  someone explain the practice in U.S.A. more in detail for
 combind sewer  and industrial waste.

 2.6    Information on Alterrative Waste Treatment Management

     Pursuant  to  section 304 (d)  (2) of the Act, information on alter-
native  waste treatment management techniques and systems available .to
implement  section 201 of the Act, is published in dividing into three
categories  (l)  treatment and discharge into navigable waters (2) land
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application techniques and (3) wastewater reuse.  In navigable waters,
where water quality standard are more stringent, effluents based on
those standards will apply and more stringent effluent limitations
including additional parameters such as ultimate oxygen demand and ulti-
mate biochemical oxygen demand will be decided.  The use of the parameters
of ultimate exygen demand means the total oxygen demand of the waste-
water effluent including organic nitrogen, especially in the form of
ammonia.  I seems to me that technology to satisfy the ammonia biologi-
cal demand is more costly and less widely achievable and is not always
practicable at the moment.  I wonder whether this kind of technology
should be called to be best practicable or not.

2.7   Infiltration/Inflow

     Pursuant to section 201 (g) (3) of the Act, the EPA Administrator
shall not approve any grant after July 1, 1973, for treatment works
under this section unless the applicant shows to the satisfaction of the
Administrator that each sewer collection system discharging into such
treatment works is not subject to excessive infiltration.  It is recog-
nized that sewage treatment of infiltration/inflow requires larger
treatment works with increased cost for capital, operation and mainte-
nance, and elimination of infiltration/inflow by sewer system rehabilita-
tion can often reduce the cost of sewage collection can often reduce the
cost of sewage collection and treatment, therefore a logical and systematic
on the total system over sewage collection and treatment is necessary to
determine the cost-effectiveness through the cost-effective analysis.
The cost-effective enalysis should be based on the comparison of the
estimated cost for treatment of infiltration/inflow and the estimate
cost for rehabilitation of the sewer system.  It seems to me that in this
case the estimate cost for treatment of infiltration/inflow may vary
sharply in either case of estimating the cost for best practicable or
best available process, in other words for secondary treatment or advanced
waste treatment.

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 2.8   Allotment  of Federal  Grants  for Construction of Treatment  Works

      As for allotment  of  federal grant  and  state  determination and  certi-
 fication of project  priority, pursuant  to section 205 (a)  the  federal
 grant of plant construction shall  be allotted among the States in accord-
 ance  with regulations  in  the ratio that the estimated cost  of  constructing
 all needed publicly  owned treatment works in each state bears  to the
 estimated cost of construction of  all needed publicly owned treatment
 works in all of  the  states.  I understand.that pursuant to  section  516
 (b) (2)  a detailed estimate, biennially revised,  of the cost of  construc-
 tion  of  all needed publicly owned  treatment'works in all of the  States
 and of the cost  of construction of all needed publicly owned treatment
 works in each of the States and the applicable percentages  to  be used in
 computing State  allotment every two years.  On other hand  the  EPA
 Administrator, pursuant to  section 516 (b)  (3) (4), shall make a com-
 prehensive study of  the economic impact on affected units of government
 of  the cost of installation of treatment facilities, and a  comprehensive
 analysis of the  national  requirement for effluent to attain water quality
 objectives as established by the Act.  Is there any possibility  for the
 Administrator to correct  the allotment of funds at the results of the
 comprehensive study and analysis pursuant to section 516 (b) (3) (4)?
 Pursuant to  the  regulation  of grants for construction of treatment  works,
 construction grants will  be awarded from allotments available  in accord-
 ance  with  a  State System  for certification of priority for  construction
 grant  project.  What kind of criteria is'used in Texas State priority
 system?

 2.9    Public  Participation

     It  is required by the regulation that the State agency has  afford
adequate opportunity for the public participation such as oral or written
municipal and public comment upon the State priority system.   Further,
pursuant to section 101 (e), the EPA Administrator, in cooperation  with
the States, shall develop and publish regulations specifying minimum
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guidelines for public participation in such processes.  Could you explain
the public participation in the development of water pollution control
program in the case of Texas State agency?

2.10   Cost-Effective Analysis

     In cost-effective analysis procedure of the guidelines pursuant to
section 212 (2) (c) of the Act it is required that the planning period
for the cost-effective analysis shall be 20 years.  On the other hand
pursuant to section 208 (b) (2), any plan prepared'under such process
shall include the idenfication of treatment works necessary to meet the
anticipated municipal and industrial waste treatment needs of the area
over a twenty years period including any requirements for the acquisition
of land for treatment purposes; the necessary wastewater collection and
urban storm runoff systems; and a program to provide the necessary
financial arrangements for the development of such treatment works.
I wonder why a twenty-year period is fixed' in those cases,  because pursuant
to the same guidelines of cost-effective analysis the service life shall
•be taken in accordance with such situations as follows;
           Land                   permanent
           Structures             30 ~ 50 years
           Process equipment      15 ~ 30 years
           Auxiliary equipment    10 ~ 15 years

2.11   Pretreatment Standards

     It seems that the federal pretreatment standards pursuant to section
307 (b) of the Act are intended to be national level in scope and in
many cases it will be necessary for a State or a municipality to supple-
ment the Federal Standards with additional pretreatment requirements in
accordance with the local condition pursuant to section 304 (f) (l) and
guidelines.  Pretreatment for removal of compatible pollutants such as
BOD, SS and so on, is not required by the Federal Pretreatment Standards.
I understand this indicates that the compatible industrial wastewater
will be encouraged to be treated in publicly owned treatment works by
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 joint treatment under the  user charge  systems.   I  understand also that
 under the National Pollutant Discharge Elimination System pursuant to
 section 402,  all point sources including  publicly  owned treatment works
 must obtain a permit  for' the discharge of wastewaters  to  the navigable
 in the United States,  permits,  however, will  not be required for industrial
 sources discharging into publicly  owned treatment  works,  and effluent
 limitations for publicly owned treatment  works  is  required including (a)
 secondary treatment information, section  304  (d) (l) (b)  toxic  effluent
 standards,  section 30? (a)  (c)  Water quality  standard,  section  303 of the
 Act, and the  most stringent  limitation for each pollutant will  govern.
 Accordingly I understand that it may be necessary  to establish  a local
 system which  will allocate waste loads to  industrial users so that
 biological  treatment  processes  are not inhibited and to ensure  that
 effluent limitations  are met.   Finally there  is one  thing in pretreatment
 for the incompatible  pollutants such as heavy metals.   In the case of
 pretreatment  to remove heavy metals there  must  be  some  difference on
 quality limitation between publicly owned  biological treatment  works and
 physical chemical treatment  works.  Supposing that  small  amount of heavy
 metals through legal  pretreatment limitation  are discharged  into publicly
 owned treatment works and  such  heavy metals will be  concentrated in the
 sludge,  and there will happen to cause difficulties in  sludge treatment
 and disposal.   In this connection there"are serious discussions in Japan
 in which any  heavy metals in any amount into  publicly owned  treatment
 works should  be  prohibited from industrial  sources  including small
 industries, and  publicly owned  treatment works  should not take  respon-
 sibility  of recieving  any heavy metals from industry.

 2.12   User Charge

      It  seems  that  the user  charge systems are  intended to enable the
 treatment authority to be financially  self-sufficient with respect to
 operation and maintenance,  because the term of  operation  and maintenance
 in this case includes replacement,  and the expenditures for  replacement
are the expenditures for installing equipment or appurtenances which  are
necessary during  the service life of the treatment works  to maintain  the
                                  16

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capacity and performance for which such works were designed and constructed,
and also user charges must be included in the charges made by treatment
authorities for wastewater collection and treatment such as payments for
local debt service for previous construction and local share of the works.
I understand that the user charge system may be a policy under which
sewage treatment works should be financially self-suport excluding re-
construction and expansion works.
     As for industrial cost recovery, it seems that the definition of an
industrial user is too broad, especially with regard to Division I -
Service - of the Standard Industrial Classification Manual, 1972, Office
of Management, because some kinds of service industries which are having
close contact with civic life discharge primarily domestic type waste,
and are different from industries contributing significant quantities of
process wastes-  In Japan discussions are now going on with regard to
the definition of the industrial user particularly relating to service
industry, because we are going to establish the specifyed sewer charging
system for industrial users in accordance with the polluters pay principle,
ppp.  Finally I would like to raise questions concerning with treatment
of stormwater and infiltration.  How the cost for stormwater treatment
and infiltration water treatment will be financed?  In our Japanese
practices user charges are levied by the way of system based on water
quantity measured by water meters installed in each house, and of course
such water quantity does not include stormwater and infiltration water,
and we cannot distribute such portion of such cost of stormwater and
infiltration water treatment to users.

2.13   Industrial Cost Recovery

     The regulations require that all grantees recover from industrial
users that portion of the grant amount of the treatment of wastewater
from such users, and an industrial users' share shall not include an
interest component.   The regulation also provides that a grantee may
retain an amount of the revenues recovered from industry equal to (l)
the amount of the non-Federal cost of the project paid by the grantee,
plus (2) the amount necessary for future reconstruction and expansion of
                                     17

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 the  project.   The  total amount retained, however, cannot exceed  50  percent
 of the  amount  recovered.  There are three points arising here  that  the
 first one  is the reason why 50 percent limitation in retainment  is  taken
 and  the  second one is  the fact that the corresponding treating authority
 may  make a profit  in this portion through industrial recovery  system, and
 the  third  one  is that  there must be arguments in which industrial users
 may  not  pay the interest component, but other industries which do not
 happen  to  discharge their wastewater into public sewers due  to their
 location cannot help providing their own plants and operating  the plants
 by their own expenditures including the interest component.

 2.14   Consideration on Reclaiming or Recycling of Water

     Pursuant  to section 201  (g) (2) (B) provides that the works proposed
 for  grant  assistance will take into account and allow to the extent
 practicable the application of technology at a later date which  will
 provide  for reclaiming or recycling of water.  At the planning or design-
 ing  basis  what kind of consideration should be definitely paid for
 reclaiming or  recycling of water?

 2.15   Planning of Storage for Water

     Pursuant  to section 102  (b) (l) (2) (3) (4) (5) of the Act, in the
 planning of storage for water quantity and regulation of stream  flow
 consideration  shall be given by the Corps of Engineers, Bureau of
 Reclamation, or other Federal agency.  The Act provides also that the
 need for value  of storage for regulation of stream flow shall  be determined
 by the Corps of Engineers, Bureau of Reclamation and the value of storage
 for  quality control shall be determined by the EPA Administrator.  It
 seems that  the  program of quality control and the program of quantity
 control  should  not be separated and should be unified at least in the
 planning basis.  It is reported that in Britain reorganization in the
 field of water service  is going to be established and 10 New Regional Water
Authorities will be established in England and Wales, and they will take
 responsibility of all water problems including quantity control, regula-
 tion of stream flow,  water pollution control, water supply, sewage
                                     18

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purification and disposal and so on.  The regional water authority which
will be established in its river .basin wide base is really single organi-
zation for water quality and quantity in all water problems.
     The British practice in this way may be of some value for our
discussion.
                                    19

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                                Third US/JAPAN Conference
HEAT TREATMENT  OF  SEWAGE  SLUDGE
                   presented by
                   Kenjiro Saito
             Chief, Sewage Works Section
            Public Works Research Institute
               Ministry of Construction
              February 12-16, 1974
            Ministry of  Construction
              Japanese Government
                     20

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                              CONTENTS
1.   Introduction ..............................................   23

  1.1   Antecedents ....... . ......... . ................ . ....... ...   23

  1.2   Laboratory tests on heat treatment  .....................   27


2.   Results of operations and problems  ....................... .   36

  2.1   Results of operations ..................................   36

  2.2   Problems on operations .................................   36

    2.2.1   Erosion and scale deposition of heat  exchanger  .....   36

    2.2.2   Smells .............................................   ^0

    2.2.3   Treatment of supernatant  ...........................   Uo

    2.2.4   Noise ..............................................   4l

    2.2.5   Plant maintenance and operation ....................   4l


3.   Tests and investigations for improvement  of  heat  treatment
     process [[[   ^2

  3-1   Wear, corrosion and baking of organic  substances in
        the heat exchanger ..... ................................   ^3
    3.1.1   Improvement of heat exchanger

    3.1.2   Corrosion test within reactor

  3.2   Deodorization

    3.2.1   Catalytic combustion method

    3.2.2   Ozone oxidation method


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                                                                Page

  3-3   Studies concerning the  treatment  of supernatant  .......   50

    3-3.1   Conventional activated sludge process	   50

    3-3-2   Step aeration process	«	•	  52

    3.3.3   Extended aeration process  	•	  55

    3-3-4   Aerobic digestion process  	  55

  3-4   Studies on the dissolution of  heavy metals  	  56


4-   Cost estimate for installation, operation and  maintenance
     of the heat treating facilities 	  58

  4-1   Method of estimating  costs 	58

  4-2   Capital costs and operation and maintenance expenses  ...  58


5-   Conclusions 	62
                                22

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                     HEAT TREATMENT OP SEWAGE SLUDGE
1.   Introduction
  1.1  Antecedents
       As of 1972, 254 sewage plants were operated in Japan,  and  the
       number now is on the constant increase'.   Those plants  were running
       mostly on a method embracing a series of processes including
       anaerobic digestion, mechanical dewatering, dumping  or incinera-
       tion.  As for the dewatering process, the mechanical method seems
       to have become more increasingly practised in recent years.  This
       is primarily because the process resting on anaerobic  digestion,
       drying with bed and dumping is being discouraged  by  an offensive
       taken by nearby inhabitants against nuisance stink,  difficulties
       in acquiring suitable plant sites, labour shortage,  etc.

       On the other hand, as more and more the  mechanical dewatering
       process has been disseminated, its characteristic problems have
       come to light.

       The following is a list of major problems and a breif  explanation
       of each -

       l)  Economics
           The mechanical dewatering process requires a  pretreatment  in
           which coagulant is dosed to thickned sludge for  increasing
           dewatering efficiency.

           In Japan, combined use of ferric chloride (Fed,)  and  lime
           is. the most commonest of all as a coagulant dose.   In  some
           cases, however, ferric sulfate (FeSO,) is used instead of
           ferric chloride.  Anyway, the chemicals accounts for as much
           as 20 to 45$ of the total operating  cost of the  sludge treat-
           ment .
                                  23

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2)  Working efficiency
    It is often that  the  content  of organic substances reaches no
    less than QQ% or  more in  the  sludge to be handled at sewage
    plants of large housing communities, local cities and especially
    those designed as a separate  sewer system conveying mostly
    domestic sewage.   This kind of sludge is very fine in size,
    and is hard to cencentrate; if it is retained in a thickener
    for 2 to 3 hours, it  will readily come afloat as scum, and
    worse the moisture content of the cake cannot be kept at the
    level of 75 to 80% unless the plant operator doses more
    coagulants than usually required.
    Increase in the  content of lime in the sludge cake increases
    sludge volume as a whole, over loading the incinerator.

    Since the separate sewer system is expected to gain popularity
    in the future, the above problems will emerge as a reality.

3)  Working conditions
    The vacuum filters, filter presses and other machines widely
    used for the mechanical dewatering process cannot do without
    constant inspection, cleaning and overhaul, and the operators
    are forced to attend them all the time.  Meantime, the working
    environment in the sludge treatment process is insalubrious
    compared to the  rest of the sewage treatment system.  Lime
    handling is really a peeve, because this fine powder is liable
    to  fly about.
                                24

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    As a consequence,  it poses grave concern over labour settle-
    ment and occupational hygiene to add to  the  fact  that the
    sludge treatment is an extraordinarily costly business what
    with upkeep, maintenance,  inspection and soaring  labour  cost.

4)  Durability of equipment
    Ferric chloride used as a coagulant is very  active  upon  metal
    structures such so chemical storage tank,  mixing  tank, piping,
    valves, gas ducts and fans in incinerator, costing  replacement
    and repair too much.  The  improvement in the materials of  such
    equipment is a matter of primary concern.

To cope with these and other various problems, emphasis has  been
placed on the development of new systems with which to  increase
dewaterability and realize remote and automated  control.

To ward off the problems resulting from the  use  of chemicals,  heat
treatment process has attracted keen attention as a promising
pretreatment method of sludge.  In Japan, this process  was consider-
ed for the first time in 1970  when the modification of  a sludge
handling system of Shyojaku Plant was projected, and  eventually
was practised after investigation of a test  plant.

In this process, sludge is heated in order to coagulate protein
in it into hydrophobic one, remove bonding water as well as  to
improve sedimentability and dewaterability by accelerating the
flocculation of suspended solids.  It is evident that the process
will save installation space and cut labour  by automation.   The
process is also favoured from the viewpoint  of sanitation that the
heating annihilates baccili and parasite eggs.

The Ministry of Construction,  while believing in the  process,
urged to appraise it from various angles of  view, turn  up problems
and provide measures against them before implementation as it  was
                                25

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concerned about the safety and durability of the equipment and
offensive byproducts such as stink and high, concentrate supernatant.

To push forward the Ministry's policy, full-scale plants were in-
stalled in Sakai (Semboku Plant),  Fujisawa (Nambu Plant)  and Sapporo
(Toyohiragawa Plant), so that the  performance of the plant facili-
ties could be assessed.   Also, the Committee for Investigation into
Sludge Handling and Disposal of the Japan Society of Civil Engineers
was entrusted with the task of conducting fundamental studies,
evaluation of plant achievements and retrieval of problems.
Realizing the significance of the  mission assigned'to it, the
Committee immediately organized a  subcommittee comprising civil
engineers, sanitary engineers, metallurgists, mechanical  engineers,
and of course sewage engineers from the municipalities operating
the full-scale plants, and embarked on research work from 1970.

Their principal subjects were:
l)  Literature research  on the process achievements in European
    countries
2)  Laboratory test on sludge available here in Japan to  elucidate
    the principles, effects and problems of the heat treatment
    process
3)  Assessment of full-scale plants based on actual operation data
    from the viewpoint of economics,  durability of facilities and
    operatability, etc.
4)  Examination of characteristics of supernatant and development
    of its treatment techniques
5)  Detection of stink factors and examination of methods for
    removing them
6)  Research of the equipment  with respect  to corrosion and bank-
    ing,  etc.
                               26

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     These surveys were actively promoted in  both field  and laboratory.
     The proceedings were made public  annually in the  form of interim
     report, and some of them were  submitted  to the Second U.S.-Japan
     Conference on Sewage' Treatment Technology.

     Submitted herewith is the summary of the final report covering the
     three-year research activities of the committee and its conclusions.

1.2  Laboratory tests on heat treatment
     In corroboration of the principles of heat treatment and for the
     purpose of obtaining the optimum  treating conditions, fundamental
     laboratory tests were conducted -using sludges from  Semboku Plant,
     Nambu Slant and Toba Plant, Kyoto.

     The results were as follows.

     l)  Both excess activated sludge  and sludge from  the primary sedi-
         mentation tank tended to be filtered quickly  when treated at
         temperatures above 180 G.   The higher the temperature, the
         lower the moisture content in the cake.  The  heat treating
         time was not a significant factor for both sludges, but with
         the temperature and time fixed, the  sludge from the primary
         sedimentation tank could create the  cake of lower  moisture
         content than the excess activated sludge did.

     2)  The higher the heat treating  temperature and  the longer the
         heat treating time, the faster the filtration rate.  With the
         treating time fixed, the filtration  rate increased in propor-
         tion to the temperature.

     3)  While the specific resistance of sludge had no  significant
                                                                    i-\
         correlations with heating  temperature and time, if up to 180 C,
         as it was largely affected by the content of  organic substances,
         it plunged down at temperatures above 190 C.
                                  27

-------
 4)  For both excess activated sludge and sludge from the primary
    sedimentation tank, BOD, COD and ammonia nitrogen in super-
    natant increased sharply from temperatures 180 C and above;
    their concentrations became higher on the higher temperatures
    and on the longer time.  Similar tendency was noticed with
    respect to the colour of the supernatant.

 5)  The solubility of heat treated sludge was higher as the
    organic content increased; namely, the highest was the excess'
    activated sludge, followed by mixed sludge and sludge from
    primary sedimentation tank in turn.  It was inferred that  some
    50 per cent of solids contained in the activated sludge would
    dissolve in some 30 min. of heat treating.

 6)  The baking of heat exchanger become violent when the heating
    temperature was increased more than 200 C.  The tendency for
    the heat exchanger to have scorches was stronger as the
    organic content increased.

 7)  It was concluded that the heat treatment as a pretreatment of
    sludge for dewatering can be carried out effectively even  with
    temperature set at 180 C and time at 30 to 60 min. if the
    organic content in sludge is in the range of 50 to 60$, while
    if the organic content varies or exceeds 60$, the heat treating
    conditions should be set at  190°G to 200°C and 30 to 60 min.

Sewage treatment plants where full-scale facilities were installed
are listed in Table 1.1.  They all were designed to handle for the
most part domestic sewage.

Table 1.1 shows the design data for each of the plants.  Their
heat treatment facilities are outlined in Table 1.2, and the
process flow of sludge treatment section is given in Pig. 1.1.
                               28

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                        Table 1.1   Design data for heat treatment  facilities in projected sites
                      Plant
ro
VD
              Items
                   Date of operation
              (l)  Sewer system
(2)   Description

      Plant area
      Served area
      Served population

      Volume of sewage
      flow, avg.


(3)   Sewage treatment
     process
               (4)  Heat treatment
                   system
                                            Toyohiragawa,  Sapporo
                             Oct., 1970
                             Combined  sewer
                             (domestic sewage only)
                                                  8.557 ha
                                              2,202     ha
                                            200,000
                                             64,OOO
                                            Activated sludge
                                            process (step
                                            aeration possible)
                              Porteous  system
                                                      Nambu, Fujisawa
Aug., 1964
Combined sewer
(partly combined &
partly incl. in-
dustrial effluents)
      9-24 ha

  1,713    ha
228,000

 76,730 mVday
Activated sludge
process (step
aeration system)
Von-Roll system
                       Semboku,  Sakai
Mar., 1969
Separate sewer
(domestic sewage only)
      8.40 ha

  1,845    ha
221,000

 86,190 mVday
Activated sludge
process (step
aeration system)
Porteous system

-------
co
o
^^Jlant
Items — ^^^^
(5) Design data
l) Quality of
influent
2) Total solid of
raw sludge
3) Moisture content
of raw sludge
4) Volume of raw
sludge
5) Moisture content
of thickened sludge
6) Volume of thickened
sludge
7) Moisture content
of heated sludge
8) Total solid of
heated sludge
9) Volume of heated
sludge
Toyohiragawa, Sapporo

B.O.D. 200 ppm
S.S. 250 ppm
20.16 t/day

99$

2,345.3 mVday

95$

403 mVday

90$

16.12 t/day

161.2 t/day

Numbu, Pujisawa

B.O.D. 200 ppm
S.S. 250 ppm
5.8 t/day

98$

288 mVday

96$

144 nr/day

92$

4.6 t/day

57.7 t/day

Semboku, Sakai

B.O.D. 200 ppm
S.S. 300 ppm
7.84 t/day

98$

392 m3/day

96$

196 m3/day

90$

5.84 t/day

54.9 t/day


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^~~~~~^~~-~^_^^^ Plant
Items ^~~~~~- — ^^_^
10 ) Moisture content
of cake
11 ) Cake volume
(6) Heat treatment
facilities and
operating conditions
l) Raw sludge
temperature
2) Outlet temperature
of heat exchanger
3) Heat treating
temperature in
reactor
4) Outlet temperature
of heat exchanger
5) Sludge cooler out-
let temperature
6) Conditioning time
in reactor
Toyohiragawa, Sapporo
M%
30.4 t/day

10°C
165°C
200 °C
55.3°C
(excl. from 1st stage)
45 min.
Numbu, Pujisawa
40$
1.1 t/day

20°C
160°C
200°C
62°C
25°C
60 _ 120 min.
Semboku, Sakai
50$
9.97 t/day

15°C
160 °C (from reactor)
200°C
60°C (to reactor)
Influent temp. + 15°C
30 _ 60 nrLnr

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                                                Table 1.2   Main plant  facilities
CO
IN3,
^\. Plant
Facilities \^
& units ^\^
(l) Appurtenances
Sludge screen


Thickner
Sludge pump

Ho. 1 crusher

Scale prevent-
ing device

No. 2 crusher

Toyohiragawa, Sapporo
Specifications

Automatic bar
screen screw
press
/I 5 m x 3.3 m
Solid pump,
/80 _ 50 x
0.3 m-ymin x
9 m x 3.7 kW
Disintegrator,
/200 mm x
30 mVhr x 2.4 m
x 5.5 kW
Electromagnetic
type?
/I 50 x 19 nP/hr

In-line type,
/200 x 38 nP/hr
x 18.5 kW

Q'ty
(a)

1


4
4

3

3


3

(b)

' 1


2
2

2

2


2

Numbu, Pujisawa
Specifications

	


-
/1 50 mm x
2 . 5 m^/min x
17 m x 22 fcW

/200 _ /I 50 mm
x 1 m^/min x 6 m
x 11 kW

	


-

Q'ty
(a)

0



3

2

0


0

(b)

0



2

2

0


0

Semboku, Sakai
Specifications

_


fill .6 m x 5-5
(3-5) m
Solid pump,
/80 _ 50 x
0.45 nr/min x
15 m x 7.5 kW
Disintegrator,
$200 °mm x
30 mVhr *
3 . 5 m x 11 kW
Electromagnetic
type,
^100 mm x
13-5 mVhr
In-line type ,
^200 mm x
13-5 nr/min x
11 kW
Q'ty
(a)

0


2
2

3

3


3


(b)

0


1
2

1

1


1


-------
oo
GO
^^\^^ Plant
Facilities
& units ^^\^
(2) Heat treatment
facilities
High pressure
sludge pump
Heat exchanger
Reactor

Sludge cooler
Heat treated
sludge
thickner
Toyohiragawa, Sapporo
Specifications


Diaphragm type,
^65 _ /100 x
19 m3/hr x
200 m x 30 kW
Counterflow
double/ pipe type,
16.8 mVhr x
18 kg/cm2 x
220 m2
Vertical
cyl inde r
^1,798 x 7,000 H
x 16.8 m3
Count erf low
dual pipe type,
16.8 m3/hr x
18 kg/cm2 x
59 m2
/7 m x 4 m x
154 m3

Q'ty
(a)


3
3
3

3
2
ss.

(b)


2
1
1

0
1
s.

Numbu, Fujisawa
Specifications


Diaphragm type,
jzfeo mm x 3 —
10 m3/hr x 30
kg/cm2 x 18.5 kW
Counterflow
double pipe type
3 - 10 mVhr x
18 kg/cm2 x
150 m2
Vertical
cylinder
>£L>750 x 7,000 H
x 14 m3
(Built in the
heat exchanger)
7,600W x 7,600L
x 5,000 W.D.

Q'ty
(a)


3
3
3

3
2
ss .

(b)


2
1
1

1
1
s.

Semboku, Sakai
Specifications


Diaphragm type,
/i65 mm x 10 m3/hi
x 250 m x 15 kW
Cojnterflow
double pipe type,
10 mVhr x
18 kg/cm2 x
approx. 165 m
Vertical
cylinder
^1,600 x 7,000 H
x 12.5 m3
Co jnterflow
dual pipe type ,
10 mVhr x
18 kg/cm2 x
40 m2
/10.8 m x
3-6 mH x 325 m5

Q'ty
(a)


3
3
3

3
Is.

(b)


1
1
1

1
Is.


-------
oo
^""\^^ Plant
Facilities^\^^
& units ^^\^^
Heat treated
sludge storage
tank
(3) Sludge dewater-
ing facilities
Filter press
& ancillary
equipment
(4) Steam generat-
ing facilities
Heavy oil fired
boiler
Toyohiragawa, Sapporo
Specifications
3»5 m x 10 m
x 2 mH x 70 m2

Horizontal type,
1,500 x 1,500 x
50 compartments
x filter area
194.5 m2


Q'ty
(a)
Is.

5

2
(b)
Is.

3

2
Numbu, Fujisawa
Specifications
-

Vertical type,
filter area,
25 m2


Q'ty
(a)
0

2

2
(b)
0

1

2
Semboku, Sakai
Specifications
/6 m x 2.7 mH
x 85 m3

Horizontal type,
1,500 x 1,500
x 75 compartments
x filter area,
292 m2


Q'ty
(a)
.s .

3

2
(b)
Is.

1

2
                                  Note:  (a):  Overall




                                         (b) :  Number of installations this time

-------
•1 f-1.   Example   of  process
                                                                                     V
                                                                                               of  jluJoe,   treatment  section
GO
en
                                                                                                                                                  thsckener
                                                                                                                                          Heat treated s/odje sttraje tank.
                                                                                                                                       3) iS/uJje CratAer
                                                                                                                                          Hijh pressure sluJte pump
                                                                                                                                       f) Heat  etcharnet
                                                                                                                                       7) Reaettt
                                                                                                                                       7X
                                                                                                                                          Deodar:j/ra  f awl: ties
                                                                                                                                       9) Heat treated s/uJjc
                                                                                                                                          Boiler
                                                                                                                                       //) Hyh pressure •sludje
                                                                                                                                          Filter
                                                                                                                                       'J) Tram fit
                                                                                                                                          Cake
a
V

»>
V


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2.   Results of operations  and problems

  2.1  Results of operations
       The three plants  surveyed where put in operation on different
       dates as shown in Table 2.1.  Their operational results in one
       year or two are summarized in Table 2.2, from which it appears
       that the sedimentability and dewaterability of sludge have been
       largely improved  by  heat treatment, and that dewatering by filter
       press has reduced the moisture content of cake to some 36 to 48%,
       sharply reducing  the cake volume to be handled and making it
       feasible to carry out landfill with cake or burn it without any
       fuel.

                               Table 2.1
       Plant             Toyohiragawa,    Nambu,          Semboku,
       	     Sapporo	    Fujisawa        Sakai
       Construction      April, 1970      June, 1971      Nov., 1970
       started
       Operation         Mar., 1971       Mar., 1972      Oct., 1971
       started
  2.2  Problems  on  operations
       The  problems which have been concerned with the heat treatment
       system are as follows.

    2.2.1   Erosion  and scale deposition of heat exchanger
           At  Toyohiragawa Plant, the heat exchanger* in its intial 18
           months of operation had part of the extension of the inside
           tube  and around T-tube in the bottom worn out to break part
           of  the latter.
                                   36

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As a temporary repair,  a sleeve tube was  put  on the broken
part, along with such measures as improvement of grit  removal
units, installation of cushion tank, and  injection of  water
at reactor outlet.

At Nambu Plant, after 6 months of operation,  some 0.7  mm  of,
abrasion was noticed at two places in the inside tube  on  the
high temperature section,  and the tube was renewed accordingly.
Also, the sludge crushing pump and heat treated sludge dis-
charge valve were found scored.

At Semboku Plant, after one year of operation,  one out of 108
inside tubes in the high temperature section  developed an
abrasion of some 0.7 mm on the outside, and was renewed.  Also,
the blades of sludge crusher were found fretted.

The troubles common to all the three plants were baking-up  of
organic substances to the heat exchanger, which resulted  in
degradation of heat conduction and increase in heavy oil  con-
sumption, not to say deterrence in plant  operation.
(sludge-to-sludge heat exchanger _ hereinafter sometimes
referred to as direct type heat exchanger _ with raw sludge
running through inside tube and heat treated sludge through
annular space between the inside tube and outside tube)
                           37

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                 Table 2.2   Operational data of heat treatment plants (from April, 1972 to Mar., 1973)
CO
oo
^^\^^ PI ant
I tern ^^\^
Average sludge
solid, tons/month
Monthly average
moisture content,
%
Heat treatment
capacity, m3/hr
Heat treating
temperature, °C
Heating time,
min.


Moisture- content
of heat treated
sludge , %
Moisture content
of sludge cake, %
Toyohiragawa, Sapporo
Max.






200

34



86.5


37.2

Mean
562

95.3

25.0

198

30



84.3


36.1

Min.






195

27



81.4


35.1

Nambu, Pujisawa
Max.






201

120



85.1


46.3

Mean
112

96.7

6.5

195

120



78.1


37.2

Min.






180

60



71.3


33.1-

Semboku, Sakai
Max.






200

Mean
107

96.1

10.2

194

Apr. _ Aug.
29.4
27.5
Sept. - Mar.
47.9
94-9


54-6

45-5
87.8


47.8

Min.






190


26.3

42.9
83


40.6


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CO
^"^-\^ Plant
Item ^^\^.^
Properties of
supernatant :-
T emperat ure , °C
pH
Total solid,
mg/lit.
Dissolved
matt e r , mg/1 i t .
S3, mg/lit.
GOD (KMn04.) ,
mg/lit .
BOD 5, mg/lit.
T-N, mg/lit.
Properties of
ef fluent :-
BOD5, mg/lit.
SS, mg/lit.
Supernatant
t re at ment
Toyohiragawa, Sapporo
Max.

53
5.7
5,950
4,040 .
2,260
1,800
6,000


17.3
41.4
Mean

43.3
5.5
5,232
3,908
1,325
1,590
5,155


11.4
25.9
Min.

28
5.3
4,838
3,690
978
1,280
3,520


5.2
18.3
Supernatant diluted
300%, aerated 24 hrs,
and then fed back to
pre-aeration tank
Nambu, Fujisawa
Max.

36.1
5.8
8,100
7,900
650
4,700
6,100
1,100

25-0
29
Mean

29-1
5.7
5,978
5,575
403
2,975
4,413
664

14.4
14.6
Min.

22.1
5.4
4,160
3,690
200
2,050
3,400
410

5.5
7
Directly discharged
to raw sewage
Semboku, Sakai
Max.

29-0
5.8
9,899
9,252
1,008
3,520
7,660
1,349

18.2
34
Mean

24.8
5-2
7,191
6,644
547
2,615
5,847
704

12.8
19-5
Min.

19.0
4.6
4,362
3,946
118
1,600
4,204
258

7.9
9
Directly discharged
to raw sewage

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2.2.2  Smells
       The sources  of offensive odors were waste gases mainly from
       the reactor  and thickener and partly from filter room and cake
       hopper.   Other plant equipment were piped together to form a
       closed  system,  and were scarcely any outlet of such stink.

       In each  plant,  the waste gas from the reactor was run through
       a gas separator and fired in1 a heavy oil fired boiler or in-
       cinerator, together with the gas coming from the thickener.
       Smelly  gas from filter and cake hopper was burnt partly in
       the incinerator and partly vented out of the stack (Toyohiragawa
       Plant)  or was  scrubbed with water and sprayed with deodorant
       (Nambu Plant).

2.2.3  Treatment of supernatant
       Table 2.2 shows the results of quantitative analyses of super-
       natant and effluent before and after heat treatment at each
       plant.   The  volume of the supernatant to be handled was largely
       dependent upon  the heating temperature, heating time, and
       thickening rate of raw sludge and heat treated sludge, but was
       about 0.5 per cent of the inflow on the average.  The character-
       istics of supernatant were roughly represented by the follow-
       ing, though  different according to specific conditions.

                pH         :  5 - 6
                COD  (KMi04) :  1,300 - 5,000 mg/lit.
                Total solid :  4,200 - 10,000   "
                BOD         :  3,500 - 8,000    "
                T  - N      :  300 - 1,400      "

       The supernatant  is high in concentration, and if it were
       returned to  the  intake of the plant for retreatment together
       with raw sewage, BOD load would be sent up by 10 to 20$.
                                 40

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       At  Toyohiragawa Plant,  the  supernatant was diluted thrice with
       'plant  effluent,  subjected to  24 hrs  of aeration and returned
       to  the preaeration tank, turning  out  satisfactorily processed
       effluent.

       At  Nambu Plant,  the supernatant was  directly discharged to the
       intake of  the  plant,  developing some  smell and dark brown hue
       in the effluent.

       At  Semboku Plant,  the supernatant was directly discharged to
       the raw sewage,  and an experiment on the treatment of super-
       natant from heat treatment  process by a step aeration process
       was carried out  by making use of  one  of the existing tanks
       with significant results.

2.2.4  Noise
       High-pressure  sludge  pump,  air compressor, boiler and sludge
       discharge  valve  were  noise  sources.

       The high-pressure  sludge pump, for example, roared at a noise
       level  of some  80 phon 1 m apart.  But those noise-generating
       equipment  were all hived into an  underground cell with its
       ceiling lined  with sound-proof materials, and served no
       problems to the  nearby inhabitants.

2.2.5  Plant  maintenance  and operation
       Toyohiragawa Plant has been maintained and operated by the
       officials  of Sapporo  Municipal Government.

       Semboku Plant  was  operated  by a private company during tiral
       run, but,  now  is operated and maintained by the officials of
       Sakai  Municipal  Government.
                                 41

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           On the contrary,  the  operation and maintenance of the Nambu
           Plant has been consigned to a private  business because of
           difficulties  in keeping operators.

           Toyohiragawa  Plant was stopped for 7 days because of pipe
           breakdown troubles and another 7 days  for two periodic inspec-
           tions (14 days in total).  During the  period, sludge was
           stored.

           At Nambu Plant, 10 days were wasted away for reasons of machine
           troubles, and 17  days were spared for  periodic inspection.
           During the plant  suspension, the sludge treatment was taken
           over by the now stand-by facilities used for chemical dose and
           vacuum filtration.

           At Semboku Plant, 19  days were wasted  away for periodic in-
           spection, and sludge  during the period was stored as in the
           case of Toyohiragawa  Plant.

           Since 10 to 20 days are necessary for  periodic inspection and
           repair,  at least  one  train of standby  facilities is indispen-
           sable, together with  a reservoir to store sludge which will
           result from the reduction of plant capacity during that period.

           Another problem is the compulsory manning requirements.
           According to  the  "Pressure Vessel Safety Rules", this kind of
           heat treatment facilities is required  to have a certified
           chief engineer for boiler operation and a certified chief
           engineer for  danger handling.

3.   Tests and investigations for improvement of heat treatment process
     In order to settle  the  problems which were turned up by the running
     of the full-scale plants, the members of the subcommittee took the
     lead  in conducting  some fundamental experiments.
                                   42

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3-1  Wear, corrosion and baking of organic  substances in  the heat
     exchanger

  3-1-1  Improvement of heat exchanger
         The heat exchangers employed were  originally of  the direct
         "kyPej as shown in Figs. 3-1 and 3.2,  in which the  inner tube
         carried low temperature raw sludge while  the annular  space,
         between the inner and outer tubes  conveyed high  temperature
         heat treated sludge.

         Rather simple in construction though  it was, wear, corrosion
         and baking of organic matter were  brought about  in the  annular
         space and T-tube which were conveying heat treated sludge.

         To solve these problems,  the following measures  were  provided,
         and the results were analyzed after three months of operation.

         (a)  Conversion of heat exchanger  from direct type to sludge-
              to-water type (indirect type) as illustrated  in  Pig.  3-3.
              With this modification, the heat treated sludge  could
              always be run through the inner  tube without  necessity
              of negotiating difficult places  where flow  pattern was
              sharply changed in section or direction, thus smoothing
              the flow and reducing turbulence.

         (b)  Installation of a cushion tank just  upstream  of  the
              automatic sludge valve.
              With this, abrupt pressure change at the time of sludge
              valve operation could be abated, minimizing abrasion  and
              corrosion.

         (c)  Pre-cooling of heat  treated sludge by water injection at
              the outlet of reactor.
                                   43

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(d)  Adoption  of a special cleaning  method in which  a cleaning
     bullet is  forced through the inner tube hydraulic ally
     with between the bullet loading and unloading ports pre-
     pared at  the inlet and outlet of the heat exchanger.
     With this,  the  cleaning time was saved, doing away with
     the overhaul of the heat exchanger.
                                               Reactor
       AW sludge.
       storage tank
Heat exchanger
       A
                                                  ~I
                                                         tSteam boiler
                                             Heat treated s/ve/oe
             Heat  treated sic/doe
             thickener        ^
                Raiu  •sludtt

      Section  A -A'
     Fig. 3.1   Process  flow sheet of direct  type
                heat  exchanger
                                 44

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                                             Cap
               .  3-2   Detail  of direct  type heat  exchanger
RO.II> studoe
    suoe

    e  ton
                                      Reactor
                   HO. I  heo.i  exchanger




                H.P sludge        B

                	   ^  (inner-
NO. Z htod  exchanger




        C        ^/W?e
                    \j
     Crusher
 /Section  B—B

 ^Section  C-C
                 (heat treated -studae )
           Pig.  3-3   Process  flow sheet  of indirect type



                       heat exchanger  (sludge-to-water)
                                45

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       In three  months  after improvement, the heat exchanger was
       disassembled and examined.  It was found that the high
       temperature  section  of the inner tube was covered with a black
       hard organic scorch  of 0.1 to 0.2 mm in thickness while other
       parts were laid  with the same but 2 to 3 mm in thickness.
       There was no abrasion nor corrosion to make mention of.  The
       low temperature  section had a soft organic layer of 0.1 to 1.0
       mm thick, but had neither abrasion nor corrosion whatsoever.
       These depositions could easily be removed by running the
       cleaning  bullet. The outer tube was covered with an oxide
       film in good condition.

       With all  these,  the  improvement measures taken were verified
       effective.

3.1.2  Corrosion test within reactor
       The heat  treating reactor is ill situated so far as corrosion
       is concerned, because it is always to bear the brunt of high
       temperature  and  high pressure in addition to constant attack
       from chemically  active water which contains much solid and is
       not deoxygenated.

       For this  reason,  the reactor corrosion problems were studied
       from the  metallurgical point of view by conducting corrosion
       tests on  mild steel  for boiler use (SB42 - JIS G3103) in
       reactors  at  Toyohiragawa and Semboku while stress corrosion
       tests were conducted at Nambu using stainless steel (SUS32).

       At Toyohiragawa  and  Semboku, mild steel test pieces indentical
       to reactor material  were set in a running reactor for 12 months.
       The results  were  as  follows.
                                 46

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         (a)   The  test  pieces were  deprived of nasty layer, and their
              remaining thicknesses were measured.  The measurements
              proved to be  almost the  same as before test, evincing that
              the  corrosion rate was very small.

         (b)   Microscopically,  the  corrosion was found uniform over the
              entire surface of each test piece.

         (c)   Also,  it  was  found that  the test pieces were protected
              with a firm film  of Fe,0 to reduce corrosion to a
              minimum,  and  therefore that the reactor material was
                                               o
              strong enough to  sustain the corrosion under service
              conditions.

         At Nambu Plant, three  kinds of stainless steel test pieces
         (SUS32,  SUS27  and  18Cr steel) which were prestressed were set
         in  a reactor for 9 months  for corrosion test.  The results
         were as  follows.

         (a)   SUS32 which was the same material as reactor's was free
              from any  problematic  corrosion symptoms like stress
              corrosion cracking, pitting and inter-granular corrosion.

         (b)   BUS27 yielded to  stress  corrosion cracking, and was
              judged unfit  for  the  reactor.

         (c)   18Cr steel showed no  stress corrosion cracking or pitting
              and were  considered to be a substitute for SUS32.

3.2  Deodorization
     As already mentioned,  each plant  was burning away smelly gases of
     the heat treating  process  in boiler or incinerator after possing
     through  a gas separator.   In order to realize a more effective
                                 47

-------
   way of odor removal,  catalytic  combustion method and ozone  oxida-
   tion method were studied  at  Semboku Plant for  2 years-  On  the
   other hand, Nambu Plant was  applied with a so-called scrubbing
   method.

3.2.1  Catalytic  combustion  method
       This  method was picked up because it was first believed that
       the plant  economy would  be  improved if smelly gas could be
       disposed of catalytically at some 200°G as 200°C steam  source
       was already available for the heat treating process.

       Odorous gases from reactor, heat treated sludge storage tank,
       heat  treated sludge thickener and supernatant storage tank
       were  forced into  a 400 / x  2,400 mm catalyzer-packed column
       and burned at 200°C to 300°C.   Then, combustion gas was
       analyzed.

       Instinctive test  verified the complete removal of odor when
       the combustion was done  at  200  C to 250 C.
       The combustion gas analyses disclosed that R~S and NH_ were
       completely removed at 250°C to  300°C and 200°C to 300 C
       respectively while CO was removed some 80$ at 200°C to 300°C
       and hydrocarbons  removed, some 50$ at 300 C.

       A gas chromatographic analysis  showed the peak of hydrocarbon
       spectrum was shifted  toward smaller molecular weight since
       molecular chains  were disjoined by catalyzer.  Compounds
       which were identified as responsible for offensive odors in-
       cluded WE,, HgS,  ethyl amine, ethyl mercaptan, .diethyl amine,
       propyl mercaptan, etc.

       M2 - group and SH -  group  of amines and mercaptans were found
       on a  gas chromatograph to have  their peak  reduced or completely
       extirpated when passed through  the catalyzer layer, verifying
                                48

-------
       that  the catalyzer was  effective to kill  radicals responsible
       for smells.

       The catalytic combustion method was thus  justified as an
       effective way to  abate  stink generated from the reactor.

3.2.2  Ozone oxidation method
       An ozone oxidation method was examined because the exhaust
       from filter room  of which majority was occupied by air diluting
       offensive odor was considered to jumbonize the catalytic
       combustion system if it was  applied.  In  a 200 $ x 3,600 mm
       reactor, smelly-compounds and ozone were  worked upon each other
       under humidified  conditions,  and the  results were judged ex-
       cellent on an instinctive test.  There was 'no sensible trace •
       of odor when ozone Was  charged several tens of ppm.  Gas
       analyses, however, revealed  that the  removal rate of total
       hydrocarbon was only 10 to 15%.  Although ozone was useful to
       cut HH? - or SH - group and  abate offensive odor, it would
       have  been not so  powerful as to dissociate hydrocarbons.

       Anyway, the  ozone method manifested itself as practically
       warrantable  for odor-killing.

3.2.3  Scrubbing method
       At Nambu Plant, high-concentration foul gases coming from
       reactor and  heat-treated sludge thickener were burned in the
       form of secondary air,  -and other subtle room odors were led
       to a scrubbing tower to wash away their soluble compounds
       with  the effluent from  the secondary  sedimentation tank (ikg
       water/kg gas).

       After scrubbing,  the exhaust  gas was  almost odorless, sub-
       stantiating  the practicability of this method.
                                 49

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3-3  Studies concerning the  treatment  of supernatant
     As explained in the foregoing, the  supernatant produced by the
     heat treatment system is higher in  concentration than that from
     the ordinary sludge treatment facilities.  If it is  returned  to
     the raw sewage where it joins influent sewage, it will increase
     B3D load by 10 to
     In order to mitigate  the  raw  sludge treatment system from BOD
     overload due to the returning of  supernatant, the following
     experimental treatments of supernatant were conducted at the
     plants.

     (l)   Conventional  activated sludge process (at Toyohiragawa Plant
          and Semboku Plant)

     (2)   Step aeration process  (at Semboku Plant)

     (3)   Extended aeration process (at Semboku and Toyohiragawa Plant)

     (4)   Aerobic digestion (at  Nambu  Plant)

  3.3.1   Conventional  activated sludge process
         A combined sewage treatment by the conventional activated
         sludge process of supernatant and sewage running in at a rate
         of 1 lit./min. was conducted  at a pilot plant of Toyohiragawa
         Plant.  1 to 2 per cent of supernatant was mixed with the
         influent sewage,though  in the actual plant the supernatant
         was about 0.5  per cent  of influent sewage.  This is because
         the experiment was designed to cover a case where it is
         required to centrally process various kinds of sludge.
         The BOD loads  were as shown in Table 3.1 below.
                                  50

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     Table 3.1   Test conditions (BOD loads.)
BOD load
Control
Case 1 (l$)
Case 2 (2$)
BOD kg/kg MLSS/d
0.08 - 0.18
0.13 - 0.28
0.23
BOD kg/m3/d
0.29 - 0.47
0.46. - 0.68
0.65
Prom the tests, following conclusions were obtained.

(l)  1 per-cent addition of supernatant brought about  some
     0.2 kg/nr/d increase in BOD load if the conventional
     activated sludge  process is applied.

(2)  1 to 2 percent addition made 0.13 to 0.28 kg/kg  MLSS/d
     of BOD load.  In case 1, the retention time in the
     conventional activated sludge process was more than 5
     .hrs, and BOD removal was some 95 per cent, showing no
     significant difference from the control.

(3)  COD(Cr) vas somewhat higher than the control's, but the
     removal rate was more than 80 per cent.

(4)  Effluent presented light yellowish brown or was  evidently
     colored compared with the control.

(5)  By the addition of supernatant, nitrogen compounds were
     dissolved into effluent with 1 to 2 ppm higher in con-
     centration than the control.  But, with the readsorption
     of metals into activated sludge, the concentration of
     metals in the effluent was held almost constant.
                          51

-------
       (6)  The growth rate of activated sludge was 1.5 to 2 times as
           much  as the control.  In case 1, settling characteristic
           of  sludge was not affected, but in case 2, it was degraded.

       (?)  The above can be summarized that the treatment of supernatant
           by the conventional activated sludge process is little or
           no problem if the adding ratio of supernatant is less
           than  1 per cent, except that the effluent is tinged with
           light yellowish brown and that the concentration of
           nitrogen compounds is increased by 1 to 2 nig/lit-

3.3.2  Step aeration process
       At Semboku Plant, the supernatant and sewage had been treated
       together on the conventional activated sludge process, but
       effluent BOD had been as high as 20 mg/lit., in addition to
       the problem that the effluent had been tinged with light
       yellow.

       In order to process the supernatant from the heat treat-
       ment  process  which was high in HDD, the step seration
       process was considered as activated sludge in its log growth
       phase was  considered preferable for the treatment of supernatant
       which was  high in BOD.  One of the existing tanks  (  effective
       capacity of 3,080 m^) was modified for step aeration process,
       and the  sludge raturnr.ate, feeding points, and other factors
       were changed to obtain the optimum operating conditions by a
       comparative method.

       Pig. 3-4 shows a schematic diagram of the step aeration process
       in which the aeration tank is divided into six sections, the
       first sectio., of which takes in supernatant and 30^ of return
       sludge, the second section receives the remaining return
       sludge and one-fifth of the primary and the third through
       sixth section equally share the remaining sewage among them.
                                 52

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In the first section,  supernatant  took   retention time of
24 hrs, and the combined sewage  took 3.4  to  3-9 hrs in other
sections.  Since SVI was a little  increased  by the admixture
of supernatant, the overflow rate  of the  final sedimentation
                          —  O
tank was reduced to 12.9 nr/m /d.   Under  these operating con-
ditions, the results were acceptable as follows.

(a)  Where the supernatant was added 0.52 to 0.72 per cent to
     the primary effluent, the effluent  (from the final sedi-
     mentation tank)  contained 5-7 to 11.0 rag/lit, of BOD,
     5.7 to 18.8 rg/lit of COD (KMn04)  (28.3 mg/lit.COD(Cr)),10
     to 15 mg/lit. of NH^-N, and less than 10 mg/lit. of S3.
     The effluent was  almost colorless and transparent .

(b)  Odor from the aeration tank was very little, and the
     pretreatment tank presented no bubbling.
                             53

-------
                                                                 Schematic   d/aQram  of  iStep  ae.ro.tion
                         Effluent
en
Find
•sedh
tank
                                                            Return
                                                treated
                                                      of
                                                                                           - aeration tank
                                              i 'mentation
                                           tank
                                                                                  30%

                                                                  tank

-------
3-3-3  "Extended aeration process
       At Semboku Plant, direct aeration of undiluted supernatant
       was tried.  In an 18-hr aeration,  BOD removal  was  removed  59
       to 66 per cent, but violent foaming carried  sludge floes away-

       At Toyohiragawa Plant,  a spare tank (806  m') was used.to
       examine two cases; aeration of undiluted  supernatant  and
                    r
       aeration of supernatant diluted with the  secondary effluent.
       In undiluted case, BOD  was removed about  47  per cent  in four
       days of aeration, and foaming was noticeable  just  as  in the
       case of Semboku Plant.

       When 300^ diluted supernatant was aerated for  a long  time
       with the aeration set at 3 m-Vhr/aeration tank, irr, the
       following results were  obtained.

       In a retention time of  32.2 hrs, supematant's BOD was removed
       84 per cent, and COD (  KMuOU  ) .28 per cent.

       In an additional 24-hr  aeration, BOD removal  rate  reached
       approximately 90 per cent.  But the supernatant, which was
       high in temperature, generated odorous gas and vapour too
       much, leaving much to be studied for their removal.

3-3-4  Aerobic digestion process
       At Nambu Plant, the supernatant was laboratory tested by an
       aerobic digestion method.

       Fig. 3.5 shows an example of digestion time  vs. BOD of mixed
       liquor and effluent.

       The test results were as summarized below.
                                 55

-------
         (a)  Aerobic digestion of supernatant under BOD load of 0.1
              kg/kg MLSS/d resulted in 95$ BOD removal-

         (b)  Judging from BOD removal and growth rate, the digestion
              time would require more than 20 days.

         (c)  Total nitrogen decreased with increase in digestion time;
              the nitrogen removal was 16 per cent for 20-day digestion
              and 56 per cent for 60-day digestion.

         (d)  With increase in digestion time, the hue was improved
              slightly, but thick brown colour characteristic to the
              supernatant was still dominant.
               2.000,
          BOD
                                               rSOO
                                               -Jffff
                                               200
                                               /OO
                                               o
                 ' 0    It    20   JO   *0   SO  "' 'it
                        Digestion  time

                Fig- 3-5   Digestion time vs. BOD
3-4  Studies on the dissolution of heavy metals
     At Nambu Plant and Toyohiragawa Plant, studies were made about
     the effects of heat treatment on the bahaviours of heavy metals
     contained in the sludge, especially with center around their
     dissolution into supernatant.
                                 56

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At Fambu Plant, have iron, chromium,  copper,  cadmium,  zinc, lead
and arsenic (seven elements in all) were  analyzed,  and heavy
elements - lead, zinc, iron, copper and cadmium at  Toyohiragawa.

Prom the studies, the following were  made clear.

(a)  The dissolving ratio which is defined as a ratio  of the total
     amount of each heavy metal in the supernatant  to  that in the
     raw sludge was 4-19 to 5-41 per cent for Fe, 0-51 to 3-41 per
     cent for Or, 4-19 p.er cent for As, 0.05  to 4.19 per cent for
     Cu, 0.7 to 9-61 per cent for Cd, 2..67 to 3-70  per cent for
     Pb, 0.42 to 1.28 per cent for Zn, all in Nambu Plant.
     In Toyohiragawa, Fe was 8.00 per cent; Pb, 0.80 per cent; Zn,
     1.3 per cent, respectively-  Namely, the dissolving ratio of
     heavy metals and arsenic was less than 10 per  cent on the
     whole.

(b)  In spite of heat treatment, more than 90 per cent of sludge
     heavy metals was retained in the cake to be disposed of.
     Accordingly, exhaust gas produced by the incineration of
     cake should be processed through a suitable precipitator in
     order to trap heavy metals.

(c)  Increase in the concentration of heavy metals  in  the effluent
     due to dissolution into supernatant  registered a  maximum of
     0.6 mg/lit. for Fe.
     Of the heavy metals controlled by the Water Quality Standards
     for Toxic Substances, such metals as Cr. , Cd  and Pb were a
                               -U
     maximum of the order of 10   mg/lit., which was considered
     not detrimental to the effluent.
                             57

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4-    Cost  estimate  for  installation, operation and maintenance of the
     heat  treating  facilities
     In order to  appraise the economics of the heat treatment process,
     the capital  cost,  operation and maintenance costs were estimated
     for each plant and compared with the anaerobic digestion-chemical
     coagulation-vacujm filtration process which is now prevailing as a
     sludge treatment method.

  4.1  Method of  estimating costs
       For each plant,  the costs were deflated to those in the 1972 yen,
       and the costs necessitated for the treatment of supernatant and
       deodorization were included.

  4.2  Capital costs and operation and maintenance expenses
       Table 4-1  shows  a comparison in capital costs between the heat
       treatment  system and the digestion-chemical coagulation-vacuum
       filtration system-  Table 4-2 shows a comparison between the two
       systems with reference to operation and maintenance costs and
       depreciation costs.

       Whether the  processing is to cover up to dewatering or up to
       incineration, there is no significant difference in the capital
       cost per solid tonnage per day between the two systems, except
       for Toyohiragawa Plant.  Up to dewatering, the capital cost reaches
       ¥ 45 to 47 million, while up to incineration it amounts to ¥' 53
       to  60 million.

       The costs  for operation, maintenance and depreciation are almost
       the same for both the heat treatment system and the digestion-
       chemical coagulation-vacuum filtration system if dewatering is
       included.  If extended to incineration, the situation turns out
       to  the advantage of the heat treatment system.  But if sophisticat-
       ed  deodorizing facilities, and treatment of supernatant, etc. are
                                   58

-------
taken into account, the advantage  cannot always go to the heat
treatment system.

In brief, the costs for construction,  operation and maintenance
are almost the same for both system for the time being.
                               59

-------
                      Table  4.1    Comparison of capital costs between heat treating system

                                   and digestion-dewatering  system
Plant
Toyohiragawa
Nambu
Semboku
Sludge
solid,
DS_T/day
40-3
17.3
23.5
Heat treatment system
up to
dewatering
¥ million
(per DS-T)
985
(24-4)
820
(47.4)
1,114
(41.4)
up to
incineration,
¥ million
.(per DS-T)
1,331
(33.0)
-
1,234
(52.5)
Space,
m2
3,150
2,460
2,730
Digestion-chemical coagulation-
vacuum filtration
up to
dewatering
¥ million
(per DS-T)
1,390
(34-5)
811
(46-9)
1,051
(44.7)
up to
incineration,
¥ million
(per DS-T)
1,801
(44.7)
1,039
(60.1)
1,329
(56.6)
Space,
m2
5,000
3,000
4,200
cr>
o
                      B.B.:  Values parenthesized  refer to  unity ton of  daily processing sludge (DS).

-------
                       Table 4-2   Comparison of upkeep costs and depreciation costs between heat  treating system
                                   and digestion-dewatering system        Ti   d  ")
Plant
T oy ohi ragawa
Nambu
Semboku
Heat treating system
Up to dewate:ri.ng
Upkeep
6,715
11,370
-
Depr.
3,620
6,630
-
Total
10,335
18,000
-
Up to incineration
Upkeep
7,130
-
6,860
Depr.
4,950
-
7,640
Total
12,080
-
14,500
Digestion-dewatering system
Up to dewatering
Upkeep
7,000
10,640
9,140
Depr.
4,070
5,590
5,220
Total
11,070
16,230
14,360
Up to incineration
Upkeep
9,000
12,600
11,100
Depr.
6,160
8,300
7,650
Total
15,160
20,900
18,750
en

-------
5.   Conclusions
     The following is  the  summary of  the  opinions formed by the committee
     in regard to  the  heat treatment  process.

       The heat treatment  process  is  still in its developing stage, and
       has many problems,  accordingly.  The Committee has obtained the
       first-hand  knowledge  about  the process based on the three-year
       investigation program.  The heat treating facilities themselves
       will be little  problem if  proper measures were taken for the
       prevention  of corrosion and organic deposition.  Dewaterability
       of heat treated sludge is  excellent, and dewatered sludge can burn
       well without any additional fuel.  But, the following problems
       still remain unsettled.

       (l)  Deodorization  of stink from heat treatment process.

       (2)  Treatment  of supernatant with high BOD (incl. removal of
            heavy  metals and nitrogen compounds).

       (3)  Establishment  of operation and maintenance system including
            periodic inspection.

       If there are municipalities which are inclined to construct the
       heat treatment  system, they should carefully examine the necessity
       of sludge incineration, space availability, prospects of manning
       for system  operation  and maintenance, and above all the costs for
       construction, operation and maintenance.

     Before the heat treatment system would establish itself and become
     accepted widely by sewage plants, it might possibly presuppose the
     following developments, along with the solution of the problems
     pointed out by the Committee.
                                62

-------
(l)  Determination of optimum operating conditions
     Quality of sludge varies with plants,  and the  optimum operating
     conditions should be determined for each plant by basic  experi-
     ments.

     Considering the quality of supernatant,  scorching of  organic
     substances and overall economy, the heat treating temperature
     and time should be as low and short as possible so long  as the
     aimed dewatering rate can be attained.  Namely, the heat treat-
     ing conditions should be optimized in  consideration of the
     entire sewage treatment process.

(2)  Establishment of closed system for heat  treatment facilities
     The cake obtained from heat treated sludge is  low in  moisture
     content and high in calorific value.  Namely,  it is desirable
     to recuperate the heat from incineration of cake for  the heat
     treatment, to use smelly gases as incinerator  combustion air
     for complete deodorization and also to reduce  the discharges
     only to ash and combustion exhaust.

     In this context, the advent of an incinerator  with a  heat
     recuperative boiler compatible to the  heat treatment  process
     is strongly hoped for.

(3)  Unitization of equipment
     The standardization and unitization of equipment should  be
     pushed forward for the purpose of simplifying  the facilities,
     facilitating quality control and saving costs.

In support of the conclusions and opinions  formed by the Committee,
the Ministry of Construction has agreed in  principle to recognize
the heat treatment system as eligible for government subsidy  pro-
grams.

-------
To complete the eligibility, however, it is necessary- to develop
new equipment meeting the abov emeriti one d requirements.

In the pursuit of this purpose,  the Ministry is starting the
assessment of the development and improvement of equipment, and
the Institute of the National Sewage Works Corp.  will play a key
role in this.
                            64

-------
                                    Third US/JAPAN Conference
COMBINED TREATMENT  OF MUNICIPAL  AND
          INDUSTRIAL  WASTEWATER
                     presented by
                    Masayuki Sat^
             Director, Sewage Works Bureau
                 Yokohama City Office,
                     Hideo Fujii
           Head, Technology Development Division
                 Sewage Works Bureau
              Tokyo Metropolitan Government
                        and
                    Seiichi Yasuda
              Director, Sewage Works Bureau
                   Kyoto City Office
               February 12-16,  1974
              Ministry of Construction
                Japanese Government
                      er,

-------
I.  -GENERAL









                            CONTENTS






                                                           Page




1.   Treatment Systems of Industrial Wastewater 	    67





2.   Considerations Required in Combined Treatment 	    70
                             66

-------
COMBINED TREATMENT OF MUNICIPAL AND INDUSTRIAL WASTE WATER

§ I.   GENERAL

  1.  Treatment systems of industrial waste water
  2.  Considerations required in combined treatment
      (l)  Technical considerations
      (2)  Allotment of expenses
      (3)  Administrative measures

  With the expansion of today's industrial and economic world which is
  built on such fundamental materials as metals and petroleums, pollution
  of public waters by industrial waste water has spread not only over
  heavily industrialized major cities and their suburbs, but also over
  farming and fishing areas, posing a serious threat to water source and
  to human health and life.
  Under these circumstances, the importance of public sewerage, the role
  of which is to treat and dispose of municipal waste water which is
  discharged continuously, has become increasingly large.   To protect
  public waters and human health and life from pollution,  work on public
  sewerage and industrial waste water must be effectively carried out,
  but it is important that we make efforts to find possible and effective
  approaches for pollution control in combination of them.
  Possible countermeasures may vary according to the circumstances in
  which a country or district finds itself, but in our present state, we
  believe it is urgent that better solutions to processing techniques,
  expense allotments and administrative systems be sought through ex-
  changing information among those who are confronted by similar problems.
  1.  Treatment systems of industrial wastewater
      The biochemical oxygen demand (BOD) load of industrial wastewater
      is'said to be several times more than that of domestic wastewater,

                                   67

-------
suggesting that the former accounts for a significant proportion of
the water pollution problem.  Furthermore, industrial wastewater is
a major source of contaminants which are threats to human health and
life.
In considering the industrial wastewater problem, possible counter-
measures to be taken may be classified as follows:
(l)  Independent treatment ...  where industrial wastewater is
     separately treated and then released directly into public
     waters.
   a)  Individual and independent treatment (A) ...  where individual
       firms and plants treat waste water independently.
   b)  Joint independent treatment (B) ... where wastewater is
       treated on a joint treatment basis.
(2)  Combined treatment ... where industrial wastewater accepted by
     public sewerage.
   a)  Accepted with pretreatment
     l)  Individual pretreatment (c) ...  where individual firms and
         plants pretreat wastewater
     2)  Joint pretreatment (D)  ...  where  pretreatment is made on
         a joint treatment basis.
   b)  Accepted without pretreatment (E-)
      The  above classification may be  illustrated as  follows:
                                 68

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              Fig.  Treatment  Systems  of Industrial waste water
                Independent  treatment
               Individual  and independent
               treatment	
             Joint  independent treatment
                  Combined treatment
            Individual pretreatment
            Joint pretreatment
Public
Sewarage
                                                         c/l
                                                         f-1
                                                         0)
                                                         I
There are many factors that must be taken into consideration, such
as location of factories, and quantities and qualities of sewage
water, before selection of a treatment system can be made.  To meet
requirements of large areas, a combination of two or more of these
systems may be employed.
From the standpoint of taking measures based on "control over the
sources", independent treatment systems A or B appear to be most
desirable, but in many cases, we have to adopt a combination of
systems C, D and E.
Where there are no effluent routes other than public sewerage, it
may be more efficient in attaining water pollution prevention to
take appropriate administrative steps rather than to force small
and medium enterprises that can hardly afford, technically and
financially, an independent treatment.
                               69

-------
  We_will now discuss some.-of the problems that may be encountered in
  employing a combined treatment.
  Considerations required in combined treatment
  The problems in planning of a combined treatment are divided into
  three principal items;  technical measures,  allotment of expenses
  and administrative  measures.
(l)  Technical measures
     It is generally  said that  "control  over  the sources of contami-
     nation" is the principal rule of combating public nuisances.
     However,  at the  same time,  a strong case can also be made for
     the efficiencies of  scale.
     In air pollution control,  no measures can be other than to do
     something about  the  very sources of contamination.
     This is mainly because  collecting emissions,  once discharge
     into the atmosphere,  is prohibitively expensive.
     In wastewater control.,  on  the other hand,  the gravity flow system
     is a skillful approach  to  collecting pollutants.   The premise
     of a combined treatment -  collecting and combining flows - is
     physically and economically feasible.
     If conditions given  below  are all met in wastewater treatment,
     a combined treatment is both useful and  practical.
     l)  Will not damage  sewerage facilities.
     2)  Will not disturb biological  treatment process and can meet
         effluent requirements  of treated water.
     3)  Will not contain dangerous substances in excess of established
         limits.
     In order to  satisfy  these  conditions,  the standards of pretreat-
     ment techniques  play an important role throughout all phases  of
                                                 •
     construction, maintenance  and management of  a treatment plant.
                                 70

-------
     The following considerations,  in particular,  are of paramount
     importance:
      (a)  Technical and financial guidance and assistance to medium'
           and small enterprises that are producing undesirable
           industrial wastewater.
      (ID)  Selection and development of sludge treatment and disposal
           methods employed during pretreatment of undesirable indus-
           trial wastewater containing dangerous substances.
(2)   Allotment of expenses
     Expenses of a combined treatment should be on a "Polluter-Pay-
     Principle" (P.P.P.) basis.   However,  because  of difficulties in
     determining quantities and qualities  of industrial wastewater
     running into common public sewerage in early  stages of building
     a treatment plant,  the trend in Japan is toward having users
     share these expenses in the form of fees.
     As for the problem of expense allotment,  our  considerations
     should not be limited to  a simple balance of  allotment.   A
     system based on water qualities and ajprogressive charging system
     should also be considered so as to provide an incentive for
     suppressing discharge pollutants.
     Administrative measures
     For the purpose of increasing effectiveness of a combined
     treatment, it is necessary that wastewater discharge from in-
     dividual firms be monitored so that it be kept within appropriate
     limits,  along with enforcement of strict wastewater' discharge
     restrictions including greater penalties to offenders.
     For a satisfactory result in administrative measures taken,
     appropriate guidance and  assistance should be employed,  rather
     than relying on restrictions alone.   Among such s"teps may be
     technical assistance covering improvements in production processes,
     particularly in medium and small enterprises,  and expansion of
     financing systems for the installation of pretreatment facilities.
                                 71

-------
It is an effective approach that the municipal authority plans
and constructs joint pretreatment systems.  And, on a greater
scale, basic policies such as formation of new industrial
districts in harmony with city planning are necessary.
So far we have discussed basic considerations required for a
combined treatment of industrial waste water, and now we will
briefly report on some examples of combined treatment in service
in Tokyo, Yokohama and Kyoto.
Yokohama  Operating conditions of common pretreatment facilities
based on the system "D" where wastewater'is collected according
to the qualities of water to be drained are discussed along
with related problems and countermeasures.
Tokyo  Chronological processes of common pretreatment facilities
that were initially started in the "D" system and were later
combined with the "C" system for processing wastewater containing
dangerous substances to meet restricted requirements on waste-
water discharge, are discussed along with future plans to introduce
public sewage treatment plants and the latest technical develop-
ments for deep aeration.
Kyoto  Results of recent experiments on improving activated
sludge methods (double-stage process and oxygen aeration) con-
ducted in the public sewage treatment plant where a combined
treatment is being carried out with the systems "C" and "E" for
processing industrial wastewater from dyeing plants, are presented.
                               72

-------
§ II.    TORIHAMA INDUSTRIAL WASTE WATER PRETREATMENT PLANT:
         HOW IT OPERATES AND PROBLEMS POK FUTURE IMPROVEMENTS

                    -  The 6ity of Yokohama  -

                              CONTENTS

                                                              Page
 Introduction
 1.   Present Servicing Status of Torihama Industrial Waste-
      water Treatment Plant ................................   77

 2.   Problems Encountered at This Plant and Their
      Countermeasures ......................................   °5
                               73

-------
§ II.    TORIHAMA INDUSTRIAL WASTEWATER PRETREATMENT PLANT:
        HOW IT OPERATES AND PROBLEMS FOR FUTURE IMPROVEMENTS

                        -  The City of Yokohama  -

Introduction
  At the recent Second U.S.-Japan Conference  on Sewage Treatment Technology,
  combined treatment  of industrial and municipal wastewaters in Yokohama
  City was reported on along with an example  of industrial wastewater treat-
  ment processes as practiced in Torihama,  a  coastal industrial district
  in Yokohama.
  Major features and  treatment methods reported are summarized as follows:
  (l)   Features
     l)  The construction and maintenance  costs relating to the joint
         treatment  of industrial wastewater is  a full charge to constituent
         enterprises,  and the construction and  maintenance activities are
         placed under the control of the City.
     2)  Industrial waste water is classified into three types:  mis-
         cellaneous wastewater (from water closets,  kichens,  etc.)
         general process wastewater (containing organic matter, oils,  etc.),
         and pickling and plating process  wastewater (discharged from
         pickling and plating factories).   Wastewater from plating and
         pickling processes is further divided  into two types,  that con-
         taining cyanide and that containing  heavy metals.
         Each type  of wastewater is properly  treated according to its
         particular physical and chemical  properties and conditions.
     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 common wastewater
         treatment  plant construction costs.
     4)  Miscellaneous wastewater,  general process wastewater,  cyanide
         wastewater and heavy-metals wastewater,  discharged from the

                                    74

-------
industrial district, are separately drained through individually
provided pipings and then treated separately according to their
physical and chemical properties and conditions before they are
sent' to a sewage treatment plant where all the wastewaters are
combined, mixed together and treated by an activated sludge
process.
A flow-sheet of these"treatment processes is shown in Fig. 1.
This paper covers the operating conditions at the Torihama
Treatment Plant since the previous report and problems
encountered that require further consideration.
                              75

-------
Fig. 1  Flow-sheet showing treatment processes at Torihama
        Industrial Waste Water Pretreatment Plant
Plant No. 1
Plant No
2 .

( Heavy metals waste water )
( Cyanide waste water
1
Pump
J

Pump
!

friary oxidation storage tank
i
Secondary
tion tank
|_
General process
waste water
Miscellaneous
waste water

i
oxida- Reduction tank

I
Filtrate
Mixing tank 	 	
J

SiM&n^nl^P^ Vacuum filter
1
Filter
J

pH controller


Relay pump


Relay pump
(NOTE) Miscellaneous » TTT ^/Hav
r waste water 4, .35.5 my day
General process 7/171 ^/A™,
Designed capacities was!e wa^er 3,421 nf/day
-£a~l?edwater 60 rf/day J
L wa§¥e~-wit§rs 340 n3/day SI
r Plant No. 1 1,097 nf/day
Plant area LPlantNo.2 3,300 rf/day



udge cake
>
J

,


Screen Screen
i . J
Pump Pump
I 1
Aerate
chambe]
,
1 priH


Oil separator
J

pH controller
j
Mixing
,

tank

sludgei Coagulation-sedi-
1 mentation tank

T-n •

.
»6

Centr
Slud


ener hp

storage


ifuge -
\
;e cake
grld
\
r
^-Supernatant

Pressure pump
*- Centrate
Nambu Sew
age Treat

-------
1.   Present Servicing Status of Torihama Industrial Wastewater Treatment
    Plant
    The Torihama Treatment Plant No.2 has been in operation since April
    of 1972.  However, due to the fact that the volume of influent has
    been much smaller than initially expected and that most of the waste-
    water processed contains oils, the oil separating units have been
    operated intermittently.
    The Torihama Treatment Plant No.l, on the other hand, has been in
    operation since March of 1973, and following a two month trial period,
    it has been operating satisfactorily.
  (l)  The number of constituent enterprises and the amount of waste-
       water
       The number of constituent enterprises as of the end of August,
       1973, and the amount of influent classified by it's type are shown
       in Table 1.
                                    77

-------
      Table 1   Number of enterprises and the amount of wastewater
"— -v,! terns
Types of \.
wastewater ^\^^
Miscellaneous
General process
Pickling and
plating process

Enterprises
Planned
169
61
6

Existing
81
41
4

Rate($)
48
67
67
Total
Wastewater
Designed
4,333m3
/day
3,421
400
8,154
Present
430m3
/day
586
270
1,286

Rate($)
10
17
67
16
        Note:  Breakdown of pickling/plating process wastewater
^""^-^^Vp lume
Types \^
Cyanide
Heavy metals
Total
Designed
60m^/day
340
400
Present
60m^/day
210
270
Rate($)
100
58
67
     As shown in Table 1,  the number of constituent enterprises entered
     has reached approximately 50$ of the designed number while the
     present volume of wastewater comes to only 16$ of the designed
     level.   The designed  volume has been reached only by wastewater
     containing cyanide, while at present, the volume of wastewater
     containing heavy metals is only 58$ of the designed volume.
(2)  Qualities of the influent and the effluent
     The quality of influent and that of effluent at Torihama Industrial
     Wastewater Treatment  Plant are shown in Tables 2 and 3.
                                78

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                                                       Table 2   Record of Treatment of Plant No. 1 (Pickling/plating process wastewater)
Item
Date
1973.6.11
6.13
6.27
7. 4
7.11
7.25
8. 1
8. 8
8.22
9.12
9.26

Type of
wastewater
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Cyanide
Metals
Effluent
Hue
Yellow
Yellow
Light jellow
Light yellow
Yellow
Lignt yellow
Light yellow
Yellow
Light yellow
Colorless
Yellow
Yellow
Colorless
Yellow
Light yellow
Colorless
Yellow
Light yellow
Colorless
Yellow
Light yellow
Colorless
Yellow
Light yellow
Colorless
Yellow
Colorless
Colorless
Yellow
Colorless
Colorless
Yellow
Light yellow
Desired level
Odor
None
Cresol
Slightly cresol
None
Cresol
None
None
Cresol
Slightly crosol
None
Cresol
Slightly cresol
None
Cresol
Mineral oil
None
Cresol
Slightly cresol
None
Cresol
Slightly cresol
None
Cresol
Slightly cresol
None
Cresol
Slightly cresol
None
Cresol
Slightly cresol
None
Cresol
Slightly cresol

Water
temp.(°C)
16.0
16.5
16.5
19.0
19.0
19.0
21.0
22.0
21.0
22.0
22,0
22.5
29.0
26.0
28.0
25-5
27.0
28.0
27.0
26.0
27.5
27.0
28.0
29-0 _,
29.0
28.0
29.0
25.5
26.0
26.0
26.0
26.0
26.0

pH
11.0
11.3
7.4
11.1
3.2
8.2
10.9
2.8
8.3
10.9
2.4
6.9
10.5
2.3
11.7
11.0
6.0
8.3
11.1
1.9
8.1
11.0
3.0
8.3
11.6
2.6
7.4
9.5
3.0
7.3
11.1
2.7
8.7
5~9
CN
(me/I)
190
13.0
12.0
160
28.0
Trace
350
8.8
4.0
_
-
0
290
1.1
23.0
290
13.0
0.7
-
-
5.8
140
0.1
0.1
150
22.0
0.3
160
3-5
Trace
190
2.0
0.1
1
and
less
T-Cr
(mg/l)
1.6
130
0.4
3-6
51
1.3
0.7
47
0.2
0.6
37
0.8

36
0.3
0.2
35

0.3
30
8.4
0.2
64
1.4
0.5
14
0.3
0.4
420
Trace
1.3
120
1.5
2
and
lie s a
Cr+6
(mg/l)
_
-
0
-
-
-
0
22
0
-
19
0
-
11
0
0
14
1.8
0
8.5
5.5
0
52
1.1
0
4.8
0
0
5.5
0
0
41
1.1
0.5
and
iless
S-Fe
(mg/1)
_
1.6
0.1
3.6
8.2
0.2
4.0
5.4

-
-
-
-
27
0.1
2.2
3.0
0.2
2.5
6.3
0.4
1.8
3.0
-
2.8
7.8
0.3
1.6
16
0.3
1.7
63
0.3
10
and
•less
Ni
(mg/l)
0.9
20
32
2.0
15
0.5
2.5
14
9-4
2.9
16
17
-
15
18
-
-
-
-
-
-
-
-
-
~
_
-
-
-
-
-
-
-
-
Cu
(mg/1)
4.3
4.2
8.5
6.4
2.9
0.6
3.2
7-5
0.4
5.3
3-3
5.6
-
4.6
4-4
5.8
38
1.3
3-4
3.7
4-5
2.3
2.4
0.1
2.1
5-0
4.5
1.2
15.0
0.3
1.7
37.0
Trace
3
and
Iless
Zn
(mg/l)
110
17
1.4
120
56
1.2
190
43
0.2
120
55
23
-
61
30
90
37
0.3
90
50
0.7
64
32
0.2
87
22
1.0
150
22
Trace
110
80
0.4
5
and
' less
Pb
(mg/l)
0.2
0.1
0.3
0.4
0.1
0.1
0.1
0.3
0.1
0.5
0.2
0.3
-
1.8
0.1
0
0.1
0
0
0.2
0
0.1
0.3
0.2
0.1
0.2
0
0
0.4
0
Trace
0.5
0
1
and
iless
Cd
(mg/l)
0.04
Trace
Trace
0.02
0.01
Trace
0
0.02
0.01
0
0
0.03
-
0.01
0.02
0
0
Trace
0
Trace
Trace
0.03
Trace
0
0
0.02
Trace
0.01
0.01
0
0
0.02
0.01
0.1
and
lleas
Remarks
Avg. vol. during June
190 m3/day
Avg. vol. during July
240 rnVday
Avg. vol. during August
270 m^/day
Avg. vol during September
270 m3/day

to
                               NOTE:   Waste waters containing cyanide and heavy metals are treated respectively before they are mixed together, and then conveyed
                                       to Nambu Treatment Plant.

-------
                                  Table  3   Record of Treatment at
Plant No.2 (general process waste water)
^\Item
Date ^^^
1973.6.20
7.18
8.15
9-19
Desired
Types
Influent
Effluent
Influent
h Effluent
Influent
Effluent
Influent
Effluent
level
Hue
Turbid
black
Turbid
black
Turbid
grey
Color-
less
Light
grey
Dark
grey
Turbid
grey
Turbid
grey

Odor
Mineral
oil
Mineral
oil
Mineral
oil
Mineral
oil
Mineral
oil
Mineral
oil
Mineral
oil
Mineral
oil

Water
temp. (c)
22.0
22.0
25.0
25.0
29.0
26.0
24-0
24-0

PH
9-9
9-1
9.1
8.6
7-7
8.5
7.6
7.5
5~9
BOD
(mg/l)
540
300
170
180
340
110
210
170
300
and
more
COD
(mg/l)
180
140
140
160
104
54
153
147

S3
Jmg/l)_
650
120
240
78
1,900
280
270
28
300
and
more
I 2 demand
lOae/l)
13
15
67
43
6
25
22
140

Cl
(ffig/1)
4,100
2,900
6,900
4,800
6,100
4,300
2,600
3,900

Oil
(mg/l)
350
100
170
15
1,200
140
110
__43_J
35
and
more
Reraarks
Avg. vol. during June
350 mVday

Avg. vol. during July
450 m^/day

Avg. vol. during August
590 rn^/day

Avg. vol. during Sept.
607 m5/day


00
o

-------
    As indicated  in  Table  2,  the  cyanide  content  in the  treated  water
    exceeded  the  desired level  particularly during  the early periods
    of plant  operation.  This was due  to  the fact that cyanide had
    been  discharged  and mixed with waste  water  which contained heavy
    metals  as a result of  misoperation by some  station operators.
    After giving  them proper  instructions,  these  kinds of  accidents
    have  been considerably reduced and are  rarely encountered today.
    You may notice that the 6-valent chromium content in the treated
    water exceeded the desired  level on the 25th  of July,  1st and 8th
    of August, and 26th of September.   This was supposedly due to an
    excess  amount of sodium hypochlorite  introduced for  decomposition
    of cyanide, causing the reduced trivalent chromium to  be oxidized
    again to  6-valent chromium  when mixed with  chromium  containing
    wastewater.   Also, unsatisfactory  treatment of  copper  is generally
    attributable  to  difficulties  in the formation of cupric hydroxide
    through coagulation as a  result of the  formation of  complex
    cyanide.
    In Table  3, it can be  seen  that the concentration of oils and fats
    in treated water exceeds  the  desired  value.   The major causes are,
    it is assumed, (l) degradation of  efficiency  in removing oils
    because of processing  various kinds of  oils flowing  into wastewater
    being processed,  (2) shortened retention period due  to,  a short-
    circuit produced in the separation tank, and  (3) insufficient oil
    separation in the natural aeration system.
    Although  removal of B  0 D and S S  is  today  done only by gravity s
    sedimentation rather than a chemical  coagulation/sedimentation,
    obtained  values  of this plant show that they  are well  within
    the desired values.
(.3}  Operation/maintenance  cost
    Operation and maintenance costs including chemicals, lighting,
    heating expenses, power,  personnel, sludge  disposal  and pipe
    cleaning  expenses are  totally charged to constituent enterprises.
                                   81

-------
     Allotment of these expenses is based upon the quantities and
     qualities of waste waters discharged from individual firms.  Shown
     in Table 4 is the Operation/maintenance cost per one cubic meter
     of wastewater,  computed from the present conditions of plant
     operation.

      Table 4.  Operation/maintenance cost per 1 m^ of wastewater
^""~~^-_^^ C o s t s
Types ^~~^\^^^
Miscellaneous
General process
Pickling/plating
process
For present
15 yen
Average 60 yen
*Average 210 yen
For designed
10 yen
Average 34 yen
Average 1J6 yen
      * Sludge disposal cost are not included.

     The operation and maintenance cost for general process and mis-
     cellaneous wastewaters runs higher than its designed cost.   This
     is because the volume of wastewater is comparatively small and
     the fixed cost,  such as personnel expenses,  is almost constant
     irrespective of the amount  of waste water.   As for pickling/plating
     process wastewater,  the amount of chemicals used  is twice or
     thrice the designed amount,  thus pushing up the cost to a very
     high level.
(4)   Operation and maintenance system
     Operation and maintenance of plant No.l and No.2  is conducted  by
     two daytime  personnel shifts and one night  shift,  on a four-man
     shift  basis.   Tasks  performed by the operators consists primarily
     of machine operation,  feeding chemicals into chemical tanks,
     maintenance  and  inspection  of equipment and  instrumentation,
     keeping daily operation reports,  and conducting simple water
     quality tests.
                                82

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(5)  Sludge and waste oils, and their disposal
   l)  Sludge disposal
       During treatment of pickling/plating process wastewater,  600  to
       800 kg (water content QQffo] of sludge containing  such  dangerous
       materials as heavy metals are produced daily.  These  substances
       should not ooze out of the sludge when disposed,  and  we are
       presently concentrating our efforts on developing desirable
       methods of disposal.
       For the time being, sludge is stored in sealed containers within
       the sewage treatment plant yard until a desirable method  of
       disposal is found.  Under study is a method in which  sludge
       cakes containing dangerous substances are mixed  with  such
       additives as clay, glass chips and sludge from waterworks and
       then heated to 1,100 to 1,200°C in a furnace.  During this high
       temperature treatment, components in the additives (mainly SiOp>
       Al20;j> Fe2CU, etc.) react with heavy metals in the sludge in a
       solid-state mutual reaction to form a glass-phase, in which
       heavy metals in the sludge are sealed inside permanently, and
       the dangerous substances enclosed are thus prevented from oozing
       out upon disposal.  The flow - sheet below shows  this process
       which is now under study.
      (a)  Sludge treatment flow-sheet under study
Plating
sludge
Sinterim
additives



1V1-L AC I




Burne


.
f
l\



T-.
Liryer

S
— 1



                                                            To atmosphere
         1  -*
                                                          Sintered sludge
                                                          (artificial gravel)
                   300°O800°C
                                    83

-------
:)  Test results obtained
  i)  The experiment has been conducted by processing dry sludge
      in a laboratory type fixed furnace.
 ii)  Tabulated below are the sintering additives and temperatures
      used.
Sintering additives
Clay
Sludge produced from the
municipal waterworks
• Sintering temperatures
1,180 to 1,220
1,150 to 1,180
      NOTE:   Blending ratio of plating sludge to sintering
             additives is roughly 25 to 75
      Sintering temperatures decrease with an increase in Ca
      content,  but furnace operation at lower temperatures
      poses a problem in maintaining desired temperatures because
      it subsequently reduces allowable baking temperature ranges.

iii)  Solubility test of heavy metals from sintered sludge
  u
5-
4-
3-

2-
1-
o-kb-
                                       Blending ratio
                                       Clay   :  Plating sludge
         _Le_ga_l_upp_er J-imit_ .OLSmg/l)
        yoo
                          y.50   y.70
                  Sintering temp. (°C)
      NOTE:    The  sample is dipped three hours at 100 C
                              84

-------
               When  sludge  is  processed  at  high temperatures,  emission of
               heavy metals into  the  atmosphere poses  a serious problem.
               We  are now studying methods  of reducing emissions into  the
               atmosphere to an absolute minimum.
               Among the  approaches under study are  to lower sintering
               temperatures by adding materials for  preventing sublimation
               of  the heavy metals contained,  and  to sinter heavy metals
               within a closed circuit furnace so  that-emission of furnace
               gases into the  atmosphere is totally  eliminated.
     2)   Disposal  of waste  oils
         Waste  oils  produced during the  treatment  of general process
         wastewater  amount  to  400 to  600'liters a  day  (water content 50$).
         These  waste oils are  removed by waste oil disposal licencees
         licenced  by the  Mayor.
         In this regard,  storage  methods of waste  oils in  treatment plant
         are subject to the restrictions specified under the Fire Act
         from the  standpoint of fire  prevention.

2.   Problems Encountered  at This  Plant and  Their Countermeasures
  (l)  Processing  capability of the joint pretreatment plant
       The  initial cost of  the joint  pretreatment  facilities are totally
       charged  to  constituent  enterprises and the  processing capacity
       of this  plant was  decided  on the  basis of estimates provided in
       reports  from  individual enterprises  as  to  the  quantities and
       quanlities  of wastewater they  were to discharge before  the plant
       was  constructed.   However,  the quantitative and qualitative waste-
       water data  reported  were in most  cases underestimated,  so that
       today the plant constructed based on these  underestimates hardly
       provides any  surplus processing capacity.   As a result,  it is
       difficult for the  plant to  allow  constituent  enterprises to
       increace their drainage volumes or change the qualities of their
       wastewater  along with the  development and expansion of  their
       business activities.
                                   85

-------
  In view of our experience,  therefore,  when a new wastewater
  treatment plant is to be built,  it is  suggested that the City pay
  part of the construction cost for the  enterprises concerned so that
  a plant with a capacity flexible and large enough to accommodate
  future expansion can be built.
  At the Torihama Plant,  there had been  a demand for an increase of
  640 cubic meters a day of general process wastewater after the
  construction of the plant was completed.   This demand has been
  admitted on the condition that additional facilities for this
  plant will be realized in the near future.
(2)  Joint pretreatment of waste water which contains oils
     Because a joint pretreatment  system has been adopted here for
     processing wastewater containing oils,  the following problems
     have been encountered:
   i)  Although oil separation facilities were originally designed
       as a aeration system,  it has been found that oil separation
       performance is inadequate today,  partly because actual
       influent contains a wide variety  of oils,  and partly because
       the concentrations of  some  of these oils have far exceeded
       earlier expectations.
       To cope with this problem,  we plan to take steps which will
       extend their retention period and to improve plant capabilities
       upon thorough investigation of physical and chemical properties
       and inflow rates of oily wastewater which are expected to
       further increase.
  ii)  All enterprises which have  gasoline filling stations and storage
       facilities are required under the Fire Act to have oil separa-
       tion facilities within their premises, but unless management
       of these facilities is well maintained, there is always a
       possibility of a large amount of  gasoline,  oil, etc.,  in
       addition to waste-oils from other enterprises, being drained
       into the sewage pipes.
                                 86

-------
    Since these offenses could lead to fire hazards in sewage
    pipes and facilities, or present difficulties in proper
    treatment processes, we have been keeping in touch with enter-
    prise operators and providing them with necessary information
    by distributing literature and holding guidance sessions.
  Facilities for pickling and plating wastewater treatment
l)  It was originally intended that pickling and plating waste-
    water be treated in three separate systems by dividing it
    into cyanide, chromium and acid/alkaline wastewaters, but due
    to the complexity and technical difficulties of piping,
    chromium and acid/alkaline wastewaters are combined and
    allowed to flow in one piping system.  As a result, we face
    the following problems:
  (a)  Since heavy-metals wastewater and acid/alkaline wastewater
       are conveyed in one piping system, trivalent iron ions
       contained in acid/alkaline wastewater is reduced to bivalent
       iron ions when reduction of 6-valent chromium takes place.
       This causes the consumption of reducing agents to increase.
       Treatment of 6-valent chromium is as follows: it is reduced
       first by lowering its pH value and then, by increasing its
       pH value, it is separated and removed as hydroxides.  The
       pH value in acid/alkaline wastewater also changes during this
       process, so the consumption of a pH adjusting agent increases.
  (b)  Bivalent iron hydroxide (ferrous hydroxide) is inferior to
       trivalent iron hydroxide (ferric hydroxide) in coagulation
       and dehydration properties.
       In consideration of the above, it is desirable that pickling
       and plating process wastewater be processes in three
       separate systems.
2)  Vacuum filters are used for dehydration of sludge, but due to
    such problems as poor quality filtrate and filtering fabric
    wash fluids in addition to large volumes of filtrate being
                                87

-------
       processed,  their loads greatly increase when the fluids are
       returned to the treating system.  This makes smooth system
       operation difficult.
       In the meantime, abundant use'of calcium hydroxide for
       increased dehydration efficiency has increased the consump-
       tion of sulfuric acid and resulted in production of extra
       sludge.
       We plan to  install more dehydrating machines,  the numbe'i1 of
       which will  be based on the results of ,the operation of exist-
       ing units.   Types of  new machines will also be thoroughly
       considered  for improvement in overall capabilities at our
       plant.
   3)  We require  that strong waste liquids produced at plating
       factories be stored temporarily within the plants and then
       discharged  continuously in small quantities sufficiently
       dilluted with routine wastewater.
       In the early days of  operations, however, dilluting operations
       by individual firms weren't always performed satisfactorily.
       As a result, considerable variations occurred and the process
       efficiencies were affected.  Today,  however, owing to the
       intensive guidance we have given operators in factries,  this
       kind of problem is seldom experienced.
       In view of  the fact that highly concentrated wastewater is
       small in quantity, it is desirable to treat it separately so
       that a uniform concentration of sewage can more easily be
       maintained.
(4)   Quantitative  and qualitative determination of wastewater for
     user charges
     The volume of drained water at individual enterprises is esti-
     mated by means of a water meter installed on the inlet side of
     its water supply.  In cases where users consume clean water in
                                88

-------
     the  manufacture of their products,  for example,  at a raw concrete
     mill,  the quantity of drained water may differ substantially
     from the  supplied water consumption.  This is where the difficulty
     in drained water volume determination lies.
     As for the determination of quality of wastewater, individual
     operators in factories are required to submit a report on it.
     We found,  however, that these stated qualities differ greatly from
     the  fact  and lack reliability.  Therefore, though time-consuming,
     it is desirable that determination be made by city officials.
(5)   Operation and. maintenance costs
     Operation and maintenance costs are computed on a liquidation
     principle at this plant, and this system has experienced such
     shortcomings as:
   l)  Operation and maintenance costs vary year by year, therefore
       their computation is quite complex and time-consuming.
   2)  Since fixed expenses, such as personnel, lighting, heating
       and water expenses, remain constant irrespective of the volume
       of wastewater discharged, early enterprises in the industrial
       district are charged at a higher rate than new ones.
   3)  Since the treatment plants are run with expenses "totally borne
       by member enterprises, it is a prerequisite that unanimous
       consent of all participant enterprises be obtained before
       giving a go-ahead to any plan for improvement or expansion
       of facilities.
     As a solution to the problems presented above, a new expense-
     allotment system based on revising user charges every two or
     three years to correct for variations in plant operation ex-
     penses may have to be worked out, rather than relying upon a
     liquidation principle.
                                  89

-------
(6)   Others
     Although it  is  difficult  in  small  scale  facilities  such as
     Torihama plant  to  prepare alternative  treatment  systems for
     emergencies,  it is desirable  to have spare parts  for  instru-
     ments,  pumps  and valves.
                              90

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§ III.   COMBINED TREATMENT OF INDUSTRIAL AND DOMESTIC WASTEWATER
         AT SHINGASHI VALLEY

                 -  Tokyo Metropolitan Government  -

                               CONTENTS
                                                                 Page
 Introduction	•>	   92

 1.   Effluent Standard  ..-	   9_k

 2.   Sludge Handling 	   97

 3.   Surcharge  	,...   97

 4.   Shingashi Treatment Plant 	   98

 5.   Discription of Shingashi Plant  	   99
                                   91

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§ III.   COMBINED TREATMENT OF INDUSTRIAL AND DOMESTIC WASTEWATER AT
        SHINGASHI VALLEY
                   -  Tokyo Metropolitan Government  -

 Introduction
   Crude trade wastewater discharged from the heavy industrial area in
   Shingashi valley was a major pollution source to the Sumida River.
   In order to remove the pollutants and renovate the river, design of
   a new waste treatment plant was'Started in 1962.  About 730 industries
   and 200,000 people were to be served by the plant.  This was the first
   attempt in Japan to -build a plant for treatment of a mixture of many
   kinds of industrial wastewater.  The plant which is named Dkima has
   been under operation since 1966.   This paper depicts an anecdot" of
   Ukima's rise and fall.
   The Ukima Plant was designed to take care of almost all of the in-
   dustrial wastewater produced in Shingashi valley.   Wastes were mainly
   from metallurgical, chemical, metal plating, food processing, pharma-
   ceutical, pulp and paper, and dye industries.  Before the plant began
   operation the wastes were discharged directly to the Sumida River.
   At present, the Ukima Plant treats 160,000 cubic meters of liquid
   wastes daily.  Detailed information on design criteria, process
   basis and historical background of the Ukima Plant was previously
   reported at the first US - Japan Conference on Sewage Treatment
   Technology in Tokyo during 1971.
                                   92

-------

^** **N. ^ « . •*



Industrial^ Grit / ^ \, j£j£j_ Eaualization
tfAatea Chamber V ) Tank"6 ' Tank


PH Control



Coagulan
1

_ . . /^^\*" ^ deration & Rapid
_•. [ Pump ] Control -». Regulation -*• Mixing -
Chamber V / m , _ ,
^ / Tank Tank Tank

1

ts
Slow
Mixing
&
Floccu-
lation
Tank
Pumping
Station
Ukima Treatment
Plant
Final
— Settl-
ing
Tank

for
».
ShingasM
Excess

Handling
factory
Sludge

                 'ig. 1   Flow Diagram of Ukima Plant
Since inauguration of the Ukima Plant operation public concern of
pollution has developed very rapidly, with a number of new regulations
installed.  It may be likened to a "kaleidoscopic change".  Living
environmental standards, water quality laws, and effluent standard
modifications are examples.  Pollution is now a popular topic in
nearly all daily newspapers and seldom does a day pass without TV or
radio reports on pollution.  The public is very sensitive to the
degree of pollution that exists and this circumstance has resulted
in an alteration of the basic idea of Ukima 's design basis.  Although
it consistently serves to save the Sumida River from organic pollution,
the Ukima plant is not a panacea.  We have come to the conclusion that
the (l) effluent standard, (2) sludge handling method, and (3) surcharge
system should be revised.

-------
    60-
    50-

    40-
    30-

    20-
    10-
       1961  62   63  64   65   66   67  68   69   70   71    72
                  Pig.  2   Strain Quality of the Shingashi River
                           (the major tributary of the Sumida)

1.   Effluent Standard
    BODc;  of 120 mg/1 and S3 of 150 mg/1 were stringent enough for the
    initial purpose  of  the Sumida River Pollution Abatement Program.
    However, in 1971, Tokyo began to believe that the effluent quality
    should be improved  to 20 mg/1 BOD^ and 70 mg/1 SS.  In addition to
    these levels the Japanese Central Government regulatory agency
    announced the following standards to apply to all waste discharges
    to the River:
      (l)  Hexane extract

      (2)  Phenol
      (j>)  Cyanide
      (4)  Alkyl mercury
      (5)  Organi c pho sphorus
      (6)  Cadmium
      (7)  Lead
      (8)  Hexavalent chromium
Mineral oil and grease
Vegetable and animal grease
        5 mg/1
        1 mg/1
        N.D.
        1 mg/1
        0.1 mg/1
        1 mg/1
        0.5 mg/1
 5 mg/1
30 mg/1
                                  94

-------
  (9)  Arsenic
 (lO)  Total mercury
 (ll)  Total chromium
 (12)  Copper
 (13)  Zinc
 (14)  Soluble iron
 (15)  Soluble manganese
 (16)  Fluorine
 0.5 mg/1
 N.D.
 1 mg/1
 3 mg/1
 5 mg/1
10 mg/1
10 mg/1
15 mg/1
These are named the "health hazard substances" and the traditional
municipal sewage plant is not capable of adequately removing these
substances.  The only way that the treatment plant effluent quality
could satisfy the standard was for the plant to refuse acceptance of
the substances.  In other words, these materials should be controlled
at their source.  Every industry is now required to install its own
pretreatment equipment for removing the "health hazard substances"
before discharging the wastewater to any Tokyo municipal sewer.
Table-1 shows the yearly change of the influent quality, which shows
a decreasing trend.

  Table-1   Yearly Change of the Ukima Influent and Effluent
            Quality
^^ 	 ^__
PH
SS
BOD
COD
T-N
inf.
eff .
inf.
eff.
inf.
eff.
inf.
eff.
inf.
eff.
1970
6.9~8.7
7.2-7.6
239
71
270
88
321
187
85.7
59.5
1971
6.7-8.6
7.1-7-7
203
78
193
64
209
97
70.5
57.7
1973
7.3~8.3
7.4-8.0
224
79
197
64
198
92
41.7
36.9
                                                                mg/i
                                 95

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Table-1  Yearly C
Table-1  Yearly Change of the Ukima Influent and Effluent
         Quality  (Continued)
^^^ — _____
CN
phenol
T-Cr
Cr+6
Cu
Cd
As
Pb
T-Hg
T-Fe
Soluble Fe
Soluble Mn
F
Zn
inf.
eff.
inf.
eff.
inf.
eff.
inf.
eff.
inf.
eff.
inf.
eff.
' inf.
eff.
inf.
eff.
inf.
eff.
inf.
eff.
inf.
eff.
inf.
eff.
inf.
eff.
inf.
eff.
1970
0.2
0.1
2.3
0.5
4.3
2.9
-
-
2.3
1.1
0.21
0.16
ED
ED
11.7
6.3
0.17
0.12
-
-
-
-
-
-
-
-
-
-
1971
0.2
0.1
-
-
3-6
1.9
1.0
0.54
1.9
0.8
0.07
0.03
0.03
0.03
6.8
3.4
ED
ED
-
-
-
-
-
-
-
-
-
-
1973
0.2
0.1
0.4
0.1
1.4
0.9
0.5
0.1
1.6
1.4
0.04
0.02
0.01
0.007
5.5
2.5
ED
ED
23.0
16.5
1.2
2.0
0.6
0.5
L 4.0
4.0
3-8
2.0
                                                                    mg/1
                                     96

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2.   Sludge Handling
    Although concentrations of the "health hazard substances" in the
    influent are less than the standard they accumulate in the primary
    or excess sludge.  Some, heavy metals are found at concentrations of
    100 to 1000 times more in the sludge as compared to the influent.
    Analytical data of the heavy metals contained in the sludge are listed
    in Table-2.  Each value in the table is considerably greater than
    found in normal municipal sewage sludge.  Referring to the "industrial
    and municipal refuse law," one may see that the numbers are so large
    that the Ukima plant sludge is considered to be "poisonous sludge"
    which is strictly regulated for final disposal.  During ultimate
    disposal of the sludge special care must be taken to protect surface
    or ground water from sludge seepage.

           Table 2   Heavy Metals Contained in Ukima Sludge and Ash
^^-^^
Thickened
Sludge
Ash
date
71-5
72-3
73-6
72-5
72-10
73-6
73-6
T-Hg
-
-
28.4
0.024
0.008
0.101
-
Cd
516
361
150
38.0
56.0
47.8
30.8
T-Cr
11,719
14,562
14,000
6,500
9,000
6,580
5,625
Cr+6
-
-
0
-
2,550
1,380
1,200
Pb
6,484
7,522
10,300
15,000
11,500
4,220
1,875
Zn
-
-
2,170
9,500
8,000
9,490
-
Cu
-
-
8,950
4,500
5,500
4,050
-
                                                         .g/kg - dry solid
m,
3-  Surcharge
    A portion of Ukima's running cost is financed by a surcharge paid by
    the industries.  The basic formula for the surcharge calculation is
    as follows:
                  C = A + 1.7 (B + S) + 180P
           C  :  Basic factor for surcharge rate
           A  :  Acidity or alkalinity load which exceeds pH 5-6 or 8.7
                 respectively.
                                    97

-------
           B  :   BOD (mg/l) fraction which exceeds 300 mg/1
           S  :   SS
           P  :   CN + Cr,    Cyanide (mg/l) fraction which exceeds 2 mg/1
                            Chromium (mg/l) fraction which exceeds 3 mg/1
    In this formula the third item, 180P,  on the right hand side amounts
    to a large portion of  surcharge.  The  original intention of the item
    was rather for the purpose of rejecting such toxicants as cyanide
    and chromium, or for applying a penalty for their presence.  It was
    also expected that the penalty would provide a financial incentive to
    the industries to control strength of  their wastewater.  However,
    contrary to  the expectation,  the industries chose to pay for discharge
    of the toxicant substances.   This resulted in several problems in
    sewer pipes  and plant  performance.   Therefore, as previously noted,
    each industry was forced to  have its own pretreatment plant and since
    early 1973 no surcharge has  been collected.
    However, we  are thinking of  a new concept of surcharge which is to
    be applied not only to Shingashi valley but also to the whole of
    Tokyo.  It is based on both  BODt and SS concentrations in the waste-
    water discharge.  All  waste  discharges whose BOD^ and SS are stronger
    than the standard domestic sewage are  subject to the new surcharge.
    The new surcharge concept is expected  to provide an equitable solution
    for all users of the Tokyo waste treatment facilities.

4-  Shingashi Treatment Plant
    When the original Ukima Plant was planned, BODj- of 120 mg/l and SS of
    150 mg/l were the controlling design criteria of the final effluent.
    The new requirement for BODc and suspended solids is 20 and 70 mg/l
    respectively.  The Shingashi Plant  is  now under construction to
    provide additional treatment of the Ukima Plant effluent.  Even
    though toxic matter is removed at the  very beginning, before dis-
    charge to the municipal sewer, refractory substances still exist
    in the influent.  With a single-stage  biological system it is
    difficult to produce an effluent containing less that 20 mg/l BODR
                                    98

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        and 70 mg/1 suspended solids.   A year of study concluded that if the
        Ukima plant effluent was diluted with crude domestic sewage it could
        be made bio-degradable.   Thus,  a two stage biological system is now
        intended,  consisting of  the Ukima Plant and the Shingashi Plant.
        In 1974, a part of the full system will be operating, and in the near
        future a tertiary plant  may be  included.

    5.   Description of Shingashi Plant
        A flow diagram and plant layout are shown in Figure 3 and Figure 4
        respectively.
     Industrial
       wastes
      222,000
Domestic Sewage
   1,009,800 m3
Ukima treatment
    plant
                          Tertiary    '
                            treatment i
                                      i
                  outfall
                                            outfall
                           Shingashi Sewage Treatment Plant
                     Fig. 3   Flow Diagram of Whole System Plants
                                     99

-------
                       Sludge thickner
                         incinerator

                              o
                             Sludge
                             Handling
                             Factory
O
O



>-3
P>
a
fv

Regulation

Aeration &



Floccutation Tank
3
3
PJ
01
a>
rl-
i— '

H-
3
0>f
i»
s
fr

Administration
Building

                                                                                                       Aeration Tank
                                                                                                                                    Final
                                                                                                                                    Settling
Tank
                                                                             Pig.  4    Dkima & Shingashi Plant

-------
 Two level settling  tanks  (primary and  secondary)  and  deep  aeration
 tanks are interesting design  features.   The  aeration  tank  is  designed
 to provide a  straight one way flow  pattern,  while traditional aeration
 tanks have a  back and forth flow pattern.  Thus a considerable saving
 of space and  head loss  are expected.

            Table 3   Settling tank  in  Shingashi Plant

                               Primary               Secondary
  Structure               2 decks                2 decks
  Plow pattern           parallel, one  way      parallel,  one way
  Retention period        1.7 hr                  2.'^  '*"*
  Overflow rate           50 m3/m2/day       Z^^tf mVm2/day
  Dimension, upper        20^   44^  3.5^        20    39-^  3.6
             lower        20    51   3-5          20    55   3-6

 Space  saving  is  one of  the important design  factors.
 The local people do not like  having a  sewage treatment plant  for
 a  neighbor.   Thus,  obtaining  land for  a sewage treatment plant is
 a  time  consuming business.  The  two deck secondary settling tanks
 at the  Ochiai plant was the first trial of this concept.  It  was
 first  installed  as  early as 1962.
 For the past  three  years a deep  aeration activated sludge  process
 has been our  research  subject.   Since  May, 1973  the pure oxygen
 process has also been  under pilot study.  The following comments
 relate  to  the development of  the  deep  aeration tank concept.
(l)   Oxygen  transfer  rate,  KLa, is  proportional to  the  0.7 power of
     the  diffuser  depth,  and electrical  consumption is  also  proportional
     to  the  same number.   Therefore,  energy efficiency  is independent
     of  the depth.  Table 4 shows  changes of KLa relatiye to the diffuser
     depth.
     The  deep aeration system may  be  considered effective when applied
     to  mixed liquor  whose oxygen  consumption rate  is large.  The
     Shingashi's aeration tank  is  such a case.
                                  101

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      Table 4   Changes of KLa Relative to the Diffuser Depth
Aeration
Tank
Depth
H(M)
6
(iSfeet)
12
(36feet)
18
(54-feet)
Diffuser
Depth
H'(M)
5.9
11.9
17.9
Tank
Volume
V(M3)
75.4
150.7
226
Air Volume
Ql
(raVzr)
47.1
85.1
46.8
83.3
167.0
60.9
122.9
227.6
Q2=QlA
(mVHr/M5)
0.62
1.13
0.31
0.55
1.11
0.27
0.54
1.01
Air
ratio
3-1
5.6
1.6
2.8
5-5
1.3
2.9
5.0
KLa
KLa(T)
(1/Hr)
0.81
1.95
0.64
1.66
3-30
1.08
5-71
9.21
KLa(20)
(1/Hr)
0.82
1.96
0.66
1.68
3.37
1.09
5.78
9.28
                   Air ratio = Ratio of air flow rate to influent flow rate

(2)  Aeration tank' depths of 60 feet do not significantly influence the
     activated sludge activity.
(3)  When air is diffused at a location deeper than 17 feet, biological
     floe won't settle in the secondary settling tank due to entrainment
     of fine air bubbles.  Super-saturation causes fine bubbles to ac-
     cumulate near the water surface and became attached to the floes.
     It is the same phenomena that occurs in the air floatation process.
(4)  Unless methods of improving the floe settlability     obtained,
     the diffuser should not be submerged deeper than 17 feet; however
     the tank depth is not limited.
(5)  Design criteria for the deep tank, with dimensions up to 30 feet
     depth, have been derived and confirmed.  Use of tanks with depths
     as much as 60 feet are now being developed.
                                 102

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 §  IV.    COMBINED TREATMENT OF MUNICIPAL AND INDUSTRIAL WASTEWATER
         IN KYOTO

                  -  The City of Kyoto  -


                                 CONTENTS

                                                                   Page

  I.   Present Conditions of the Area Covered by the Sewage
      Treatment Plant Concerned ..................................   10U

     1-1.  Actual Situations of Factories and the Quantity of
           Inflowing Sewage ......................................
     1-2.   The Characteristics of the Inflowing Sewage ...........   106

 II.   The  Treatment Experiments of the Inflow of Route B .........   10Q

    II-l.   The Treatment Experiments at a Low Load by Existing
           Facilities ............................................   109

    II-2.   The Two Stage Treatment Experiments by the Activated
           Sludge Process at a Pilot Plant .......................   Ill

    II-3.   The Treatment Experiments by the Activated Sludge
           Process with the Pure Oxygen Aeration .................   115

III.   Conclusion .................................................   127
                                  103

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§ IV.   COMBINED TREATMENT OP MUNICIPAL AND INDUSTRIAL WASTEWATER
       IN KIOTO
                -  The City of Kyoto  -

I.  Present Conditions of the Area Covered by the Sewage Treatment
    Plant Concerned
 1-1.   Actual Situations of Factoties and the Quantity of Inflowing
       Sewage
       At the Kisshoin Sewage Treatment Plant, there are two units of
       the treatment facilities named Route A facilities and Route B
       facilities,  respectively.  Route A facilities are for Sujaku Line
       sewage and a part of Karahashi Line sewage, and Route B facilities
       are for only Karahashi Line sewage.
       Karahashi Line covers an area of 128 hectares in the south of
       Kyoto City,  where are a number of factories for dyeing, electric
       appliance manufacturing, gilding, and others.  As shown by Figure
       1-1, 48$ of Karahashi Line sewage is treated by Route B facilities.
    Karahashi Line
       Sujaku Line
                          60,000
 Route B
facilities
                                                        Route A
                                                       facilities
             Q
              Discharge
             Fig.  1-1  Flow Sheet of Kisshoin Treatment Plant
                                    104

-------
The pH value of the sewage from such factories largely fluctuates
and, therefore, the sewage can hardly be treated by the ordinary
activated sludge process satisfactorily.  As a result, a two stage
treatment has been conducted at the Plant now by leading the
effluent from Route B facilities to Route A facilities.
Tables 1-1 and 1-2 show the results of the research which were
made in 1969 on the Karahashi Line sewage.  According to Table 1-1,
41$ of the area covered by the Line is residential areas and only
20$ is factory sites.  Table 1-2 indicates that only 13$ of the
total number of factories is dyeing industry but that it occupies
32$, the largest portion, of the total factory sites.

                Table 1-1   Area Ratio by Land Use
Factories
20.0
Residences
41.0
Offices
6.0
Roads & Parks
21.8
Railway Sites
11.2
Total
100
           Table 1-2   Factory Ratio by Industrial Type

Dyeing
Machine Mfg.
Metal Work
Food Mfg.
Electrical, Mechanical
Work
Others
Total
Number of
Factories
12.5
29.8
15.4
8.1
6.7
32.5
100
Area
31.9
31.2
3-5
1.7
3.7
28.0
100
Sewage
Discharged
64.6
9.1
4.7
10.0
3.3
8.3
100
Out of the inflowing sewage amounting to 30,000 m^/day, 22,900
mVday, 76$, is the waste of factories, while the remaining 24$
is the domestic sewage and others.  Of the factory sewage, 14,800
m^/day, 65$, is the dye waste.
                              105

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1-2.   The Characteristics of the Inflowing Sewage

         Table 1-3   The Quality of the Inflowing Sewage (in 1972)

Temperature °C
pH
BOD mg/1
C 0 D Mn mg/1
Total Solids mg/1
Fixed Solids mg/1
Suspended Solids mg/1
Soluble Matter mg/1
Total Nitrogen mg/1
Ammonia Nitrogen mg/1
Albuminoid Nitrogen mg/1
Nitrite Nitrogen mg/1
Nitrate Nitrogen mg/1
Iodine Consumed mg/1
Chlorine Ion mg/1
Total Phosphorus mg/1
Phenol mg/1
Anionic Detergents mg/1
No. of Coliform Colonies
colonies/ml
Inflow to Route B
Average
26.3
8.9
363-3
215.1
1,461
1,039
116
1,355
38.21
2.78
14.43
0.27
0.28
124.6
112.9
2.37
0.35
8.7
12,000
Maximum
30.6
9.8
632.5
348.0
2,075
1,287
147
1,875
67.51
9.65
45.15
0.98
0.56
300.8
199.5
3.00 -
1.23
24.0
34,000
Minimum
22.0
7.4
193-8
28.1
834
618
77
746
14.41
0.16
2.20
0.04
0.04
7.9
12.1
0.77
0.00
1.4 -
19
      As shown by Table 1-3,  the inflow to Route B has been greatly
      affected by industrial  waste,  especially by dye waste.  Now the
      special features of the waste  quality,  which should be taken into
      consideration for the treatment,  and their causes are examined.
    (l)   pH
         Often the inflowing  waste is alkaline.  Since a great amount
         of alkali,  such as sodium hydroxide  (NaOH) and sodium silicate
                                ioe

-------
              ,  is used for the dyeing, the waste is surmised to be
     alkalized.   At the maximum, pH in the waste reaches 10, but
     sometimes the waste is acidified to pH 4 to 6.
(2)  BOD
     Compared with the ordinary municipal sewage, the inflow usually
     has a higher BOD and its amount largely fluctuates.  The average
     BOD is 300 mg/1, and it often exceeds 400 mg/1.  On Sundays and
     national holidays, it comes down to as low as 100 mg/1.
     Further even.within a single day, it largely fluctuates as
     shown by Figure 1-2.  At the peak hour it reaches as high as
     600 to 800 mg/1.
BOD
mg/1
     1000-
             11
13   15   17   19    21    23
   Time (hundred  hours)
               Fig. 1-2   Hourly Variation of BOD
     In the inflowing waste, 80$ of the BOD is soluble BOD.  Only
     0 to 20$ of the BOD can be removed at the primary sedimentation
     tank and consequently the BOD load in the aeration tank has
     become high.
                                 107

-------
(3)  Reducing Agent
     Sometimes by the waste as much as 300 mg/1 of iodine, is con-
     sumed.   It is surmised to be due to the reducing agent contained
     in the  waste.  Actually reducing agent, such as sodium thiosulfate
     (NapSpOv), sodium sulfite (Na2SO^), and sodium sulfide (^28),
     is used as an auxiliary agent for dyeing.
(4)  Soluble Matter and Suspended Solids
     In the  inflowing waste,  the  total solids,is approximately 1500
     mg/1 on the average.   Of the solids,  the suspended solids is
     only about 100 mg/1 and most of the solids is soluble  matter.
     Further, of the total solids, the volatile matter is only 35%.
     It means that the waste is highly contaminated by inorganic
     soluble matter.
(5)  Nitrogen and Phosphorus
     There is not much ammonia nitrogen but is  a considerable
     amount  of organic nitrogen in the waste.
     The amount of phosphorus is  a little  and the total phosphorus
     is approximately 2 mg/1.
(6)  Coloring by Dyestuff
     Since the waste  has been colored by dyes,  it brings about a
     feeling of contamination.
                              108

-------
II.   The Treatment Experiments of Inflow to Route B
     Any organisms peculiar to the activated sludge can hardly be found
     in the aeration tank of Route B.  It means that the inflow to Route
     B can scarcely be treated by the ordinary process.  Further if the
     mixed liquor suspended solid is given more than usual, the activated
     sludge is decomposed because of poor supply of oxygen, and the
     treatment efficiency is impaired on a large scale.
     At present the BOD removal is 30 to 50% and the SS removal is 10 to
     30% by the Route B facilities.  Therefore, by existing facilities
     and at a pilot plant, various experiments were conducted on the
     treatment of Route B sewage.
 II-l.  The Treatment Experiment at a Low Load by Existing Facilities
        ¥ith the quantity of the inflow limited to 200 in-Vhr and with the
        conditions fixed as shown by Table II-l, an experiment was con-
        ducted.  The results are shown by Table II-2.

                 Table II-l   Conditions of Experiment
Inflow m /day
Air Supplied
Aeration Period
M L S S
R S S S
BOD-SS Load
Detention Period in Final
m* air/in-^ sewage
hrs
mg/1
mg/1
kg/SS kg- day
Sedimentation Tank hrs
4,260
15.8
11.4
2,336
6,262
0.129
4.10
      "(l)
           The pH in the inflow fluctuates between 10.5 and 9.2 and its
           average is about 10.  In the grid chamber, pH is adjusted, but
           pH in the effluent from the primary sedimentation tank still
           fluctuates between 8.9 and 6.3-  This fluctuation, however,
           does not hamper the biological treatment.  The pH in the
           effluent from the final sedimentation tank is only 7.5 to 7-1.
                                    109

-------
             Table II-2   Results of Experiment
Hundred
Hours
9
11
13
15
17
19
21
23
1
3
5
7
Average
PH
Inflow
10.0
9-9
9.5
10.1
10.4
9.9
9.6
10.2
10.2
10.5
9.2
10.3
10.5-
9.2
Primary
Effl.
6.3
6.3
6.7
8.4
8.9
8.9
8.7
7-8
7.9
8.0
8.3
7.6
8.9~
6.3
Final
Effl.
7-4
7 = 3
7.2
7.1
7.2
7.4
7-5
7.4
7.4
7.4
7.4
7.4
7.5-
7.1
BOD mg/1
Inflow
239
526
206
289
211
252
220
177
206
95
160
137
226
Primary
Effl.
200
283
278
244
241
272
328
223
203
210
142
156
232
Final
Effl.
19
2.1
24
24
25
25
23
25
24
21
16
17
22
SS mg/1
Inflow
75
106
73
262
97
81
73
31
20
13
29
18
74
Primary
Effl.
54
146
62
108
84
68
113
22
51
29
53
39
69

Final
Effl.
12
25
45
47
44
28
23
38
25
50
27
39
33
(2)  BOD
     The BOD in the inflow largely fluctuates between 526 and 95
     mg/1.   The average is 226 mg/1.  The fluctuation of BOD in the
     effluent from the primary sedimentation tank is small being
     between 328 and 142 mg/1, but BOD has not been removed in the
     tank.   In the effluent from the final sedimentation tank,
     however, BOD is 22 mg/1 on the average having been removed
     satisfactorily.
(3)   S S
     Suspended solids in the inflow is between 262 and 13 mg/1 and
     the average is 74 mg/1.  SS can hardly be removed in the primary
     sedimentation tank,  and the primary sedimentation tank of Route
     B functions only to average the inflow quality.
     By the  conditions that greatly differ from the ordinary
     activated sludge process,  as shown by Table II-l, the ciliata
                           110

-------
         peculiar to the activated sludge are proliferated and  the
         effluent is satisfactory.

II-2.   The Two Stage Treatment Experiment by the Activated Sludge
       Process at a Pilot Plant
       The aforementioned experiments prove the fact that to  treat  the
       Karahashi Line -sewage the load has to be made lower than the
       standard conditions of the activated sludge process.   It is,
       however, inadvisable to newly build and maintain  such  low load
       facilities.  Therefore, in the hope that a more effective process
       might be found, a two stage treatment by activated sludge was
       experimented.
                  1st stage
                                              2nd stage
primary
Effluent

Aeration
Sedimen-
tation
Effluent 1

Aeration
Sedimen-
tation
Effluent 2

               Aero-accelator

           Fig. II-l   Flow Sheet of Two Stage Treatment
       As shown by Figure II-l, after the aero-accelator  the effluent
       is to go through another aeration and sedimentation  tank.  By
       this method, two experiments were conducted with the operation
       conditions different from one another.
     (l)  Experiment I
             Table II-3
Conditions of Experiment I

Air Supplied
Aeration Period
M L S S
R S S S
BOD-SS Load
Detention Period
UK air/irr sewage
hrs
mg/1
mg/1
kg/SSkg-day
in Sedimentation Tank hrs
1st stage
8.2
1.63
3,000

0.89
1.5
2nd stage
8.9
4.33
1,900
7,000
0.35
1.28
                                   111

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     Most of the conditions,  as shown in the Table, are standard
     except the supplied air  which is much more than usual.  The
     results are as shown in  Table II-4.  According to the Table,
     BOD in the effluent 2 is 18 mg/1 on the average.  The BOD
     removal is 47.4$ at the  first stage and 75-4^ at the second
     stage.  In the second stage there can be seen a considerable
     number of ciliata peculiar to activated sludge and the result
     is satisfactory.

           Table II-4   Results of Experiment I

pH
T S mg/1
S S mg/1
BOD mg/1
BOD Removal %
Inflow
11.5 - 4.3
7.5
725
68
476 - 23
163

Primary
10.3 - 4.6
7.7
659
46
324 - 35
139
14.7
Effl. 1
8.8 - 6.9
7-7
536
23
129 - 14
73
47.4
Effl. 2
7.7 - 7.2
7.5
482
21
37-4
18
75.4
(2)   Experiment II
     For Experiment  II,  five  sets  of  conditions  were  employed for
     the second stage  while  the  load  of the  first  stage was kept
     constant,  so  that the most  effective  conditions  for the
     treatment  might be  found.

          Table II-5   Conditions  of  Experiment  II

M L S S mg/1
BOD-SS Load kg/SSkg-
day
Aeration Period hrs
Air Supplied
EKair/m3sewage
Det. Per. in Sed
Tank hrs
Period of Experiment
1st stage
II-1-5
3,000
0.81
1.0
5
1.15
Oct 1 ~
Nov 21
2nd stage
II-l
2,000
0.150
6.0
14.7.
1.77
Oct 1~
Octl2
II-2
1,850
0.195
5.0
12.2
1.47
Oct 13~
Oct 23
H-3
1,400
0.255
5.0
12.2
1.47
Oct 24-
Nov 2
II-4
1,200
0.302
5.0
12.2
1.47
Nov' 3~
Nov 9
II-5
1,250
0.402
4.0
9.8
1.18
Nov 10~
Nov 21
                               112

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While the experiments were carried out, the quality of each
effluent was tested.  The results are shown by Table  II-6.
The BOD-SS load at  the first stage is between 0.78 and 1.13
kg/SSkg-day.  The BOD removal at the first stage is approximately
45$ at the Experiments II-l and II-3, but at other experiments
it is 20$ on the average.  At the second stage, the Experiment
II-l shows the maximum BOD removal, 80.9$.  At the other
experiments it is 68$ on the average.
No ciliata peculiar to activated sludge can be seen in the
effluent from the first stage, but after the second stage the
ciliata can be seen.
The conditions and  the results of the two stage treatment ex-
periments at a pilot plant are as follows.  At the first stage
under the following conditions, the BOD removal is 40 to 50$.
     BOD-SS load  	  approx. 0.8 kg/SSkg-day
     Aeration period  ....  1.6 hours
     pH	*	  lower than 10
After the second  stage, which is operated with the following
conditions, the BOD removal becomes satisfactory with BOD in
the Effluent 2 being less than 20 mg/1.
     BOD-SS load  	  0.15 to 0.2 kg/SSkg-day
     Aeration period  ....  approx. 6 hours
     Ca-T (MLSS (mg/1) x Aeration period ... 12,000 - 13,000 up
     Air supolied  	 15 HK air/m^ sewage
                               113

-------
Table II-6   Results  of Experiment II

Dates of Tests
Primary Effluent
BOD mg/1
PH
T S mg/1
S S mg/1
1st Stage
BOD mg/1
BOD Removal %
pH
T S mg/1
S S mg/1
M L S S mg/1
Aeration Period hrs
S V I mg/1
BOD-SS Load kg/SSkg •
day
2nd Stage
BOD mg/1
BOD Removal %
PH
T S mg/1
S S mg/1
M L S S mg/1
Ca-T
Aeratio'n Period hrs
S V I mg/1
BOD-SS Load kg/SSkg.
day
II-l
Oct 11
Oct 12
153-3
10.6-6.0
710
84
80.8
47.2
9-5-6.9
634
59
3,127
1.0
63.3
0.85'
15.5
80.9
7.9-7.6
610
43
2,012
12 , 070
6.0
80.9
0.123
II-2
Oct 22
Oct 23
158.8
10.8-5.7
•1,032
134
124.0
21.9
10.2-7.2
964
96
3,455
1.0
58.8
0.80
34.0
72.6
7-9-7.7
900
68
1,700
8,500
5.0
75.4
0.270
II-3
Nov 1
Nov 2
186.7
10.7-5-9
1,022
123
•105.4
43-5
9-3-7.0
961
122
3,580
1.0
56.5
0.90
33.6
68.1
7.9-7.4
913
62
1,372
6,860
5.0
73.1
0.285
II-4
Nov 8
Nov 9
188.1
11.3-5.1
1,091
130
136.6
27.3
10.4-7.2
1,009
112
4,169
1.0
53.4
0.78
41.4
69.7
9.2-7.9
933
118
1,357
6,790
5-0
79.5
0.373
II-5
Nov 20
Nov 21
217-5
11.1-4-7
1,167
130
195.5
10.2
10.3-6.3
1,119
127
3,334
1.0
49.5
1.13
77.7
60.3
8.4-7.2
979
86
2,123
10,620
5.0
73-5
0.343
                   114

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II-3-   The Treatment Experiments  by the Activated Sludge Process with
       the Pure Oxygen Aeration
       As mentioned above,  to  treat the sewage of Route B by the activated
       sludge process, a  remarkably large amount of oxygen is required in
       the aeration tank.   That is, to supply oxygen enough for the treatment,
       the amount of air  and  the  aeration period has to be made three times
       than usual, respectively.   It is inadvisable to build and maintain
       such air system facilities as to meet the requirements aforementioned.
       Therefore, the pure  oxygen aeration process, which was surmised to
       easily increase the  supply of oxygen, was experimented at a pilot
       plant, which is illustrated by Figure II-2.
                    Oxygen bomb
                                                Gas
                                               exhaust
  Primary      Adjusting
  sedimentation  tank
  tank of
  Rout B
       Legend:
         ©  Compressor
         d>  Pump
         (|p  Motor
             Valve
             Gas meter
Return sludge
                                               Excess sludge
                                               sampling points
       ©  Inflow
       ©  Effluent
       0  Mixed Liquor
       ©  Return sludge
             Fig. II-2   Flow  Sheet  of Pure Oxygen Aeration Process
                                      115

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      Conditions  of Experiments
      The  outline  of  the  experiments  of  the  treatment  by the pure
      oxygen aeration process is  shown by  Table  II-7-   For the Ex-
      periments I  and II,  the effluent from  the  primary sedimentation
      tank of Route B was used as  the inflow.

             Table II-7   Conditions of Experiments

Ace .
Exp
I
Exp
II
Exp
III
1
2
1
2
A.
1
Remarks
Acclimation
of Activat-
ed Sludge
Quantity of
Inflow
Constant
Quantity of
Inflow
Variable
Mixed
Ordinary
Municipal
Sewage
Inflow
Variable
Period
31 days
Jan 18 to
Feb 17
16 days
Feb 18 to
Mar 5
30 days
Mar 6 to
Apr 4
32 days
Apr 5 to
May 6
21 days
May 7 to
May 27
9 days
May 28 to
Jun 5
9 days
Jun 6 to
Jun 14
Quantity
of Sewage
m3/d
48
36
48
48
37.6
48
57.8
Aeration Period
Q
hrs
3
4
3
3
3.8
3
2.5
Q + R
hrs
2.2
2.9
2.1
2.2
3.0
2.4
1.9
Detention
Period at
Final Sed.
Tank hrs
3-3
4.3
3.2
3-3
4.5
3-6
2.9
Legend:   Q ...  Quantity of inflow
          R ...  Quantity of return sludge
          Ace.  & A.  ...  Acclimation
                            116

-------
    Firstly,  by  the  Experiment  I,  the  conditions that  make the
    treatment effective  at  a constant  inflow were found out.  Then
    at  Experiment  II,  it was aimed to  find out,  with the finding
    of  Experiment  I  made use of,  the most appropriate  conditions
    for the  treatment  of variable  inflow which is similar to  that
    of  Route B.
    The Experiment III was  made to see the efficiency  of the  mixed
    treatment of Route B sewage and the ordinary municipal sewage.
    The mixing of  those  two types  of sewage was done in the ratio
    of  1 to  1 and  the  hourly variation of inflow was made in  the
    same pattern as  that of Experiment II.
(2)  The Results of Experiment
    To  complete the  experiments,  it took nearly five months from
    January  28 to  June 14 of 1973.  Tables I1-8, II-9, and 11-10
     show the average values at each experiment of the  operation
     conditions,  the water quality examinations, and the activated
     sludge examinations, respectively.
                                 117

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                             Table I1-8   Operation Conditions

Quantity of Inflow m3/day
Return Sludge mVday
Ratio of Ret Sludge %
Aeration
Period
Oxygen
Q hrs
• Q + R hrs
Supplied m3/day
Exhausted m3/aay
Ratio in Exhausted %
Used kg/day
Ratio of Used fo
BOD-SS Load kg/SSkg-day
BOD-VSS Load kg/VSSkg-day
BOD Load Rate kg/m3-day

Final
Sedi.
Tank

Overflow Rate m3/m2-day.
Solid Load kg/m^-'day
Detent. Per. hrs
Depth of Sludge cm
Blanket
Excess Sludge m^/day
Excess
Sludge
SS kg/day
VSS kg/day
Exc S3 per Rem BOD kg/kg
Oxy used p Rem BOD kg/kg

Ace.
48
19
40
3.0
2.2
8.44
1.61
54
10.83
89.7
0.33
0.53 '
1.67
14.8
103.4
3-3
198
0.14
2.45
1.77
0.28
1-25
Exp. I
1
36
14
38
4.0
2.9
8.47
1.89
56
10.60
87.5
0.27
0.41
1.52
11.0
85.3 '
4.3
181
0.15
3.12
2.15
0.38
1.28
2
48
20
43
3-0
' 2.1
14.00
2.40
57
17.99
89.4
0.37
0.56
2.35
15.0
137-4
3.2
175
0.22
4.65
3.03
0.39
1.42
Exp. II
1
48
17
35
3-0
2.2
16.33
5.89
53
17.59
78.1
0.28
0.41
1.80
15-0
131.1
3-3
136
0.21
5.37
4.07
0.54
1.95
2
37.6
11
29
3.8
3.0
16.13
8.09
56
14.15
68.3
0.25
0.37
1.62
12.0
96.8
4.5
81.
0.07
2.47
1.67
0.26
1.76
Exp. Ill
A.
47.9
12
26
3.0
3.4
14.67
8.00
55
14.71
70.1
0.34
0.48
1.94
15.0
107.5
3-6
110
0.09
3.26
2.30
0.29
1.32
1
57.8
17
30
2.5
1.9
16.46
8.85
57
16.34
69.4
0.32
0.45
1.87
18.0
135.3
2.9
170
0.18
5.04
3.61
0.47
1.78
Legend:
    Ace.  and A	
    Exe  SS per  Rem BOD
    Oxy  used p  Rem BOD
Acclimation
Excess S3 per Removed BOD
Oxygen Used per Removed BOD
                                        118

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Table II-9   Results of Water Quality Examination

Temperature °C
E
Transparency cm
E
PH
Max
I Win
Ave
Max
E Min
Ave
Total Solids I
mg/1 E
Soluble
Matter
Suspended
Solids
Volatile
Matter
Dissolved
Oxygen
BOD
Soluble
BOD
CODCr
Soluble
CODcr
CODMn
Soluble
CODMn
Alkalinity
Total
Nitrogen
I
mg/1 E
mg/1 I
E
Rem %
I
mg/1 E
Rem %
mg/1
E
I
mg/1 E
Rem %
mg/1
E
I
mg/1 E
Rem %
I
mg/1 E
Rem $
I
E
Rem fo
mg/1
E
mg/1
E
mg/1
E
Ace.
20.0
19.0
3-5
6.5
9.0
3.2
7.0
6.9
5.7
6.2
995
790
890
745
82
26
68.3
49
16
67.4
0.0
0.4
210.5
30.0
85.8
170.4
22.2
432.4
171.0
60.5
330.5
152.8
53-8
115.8
65.0
41.6
108.8
61.3
102.5
99.0
51.27
33.31
1-1
20.4
19.6
3.0
6.0
9.3
3-6
7.6
6.7
6.1
6.4
1,330
1,230
1,180
1,160
122
51
58.2
61
23
62.3
0.0
0.8
253-9
23.6
90.7
210.4
11.8
413-0
161.7
60.9
277.5
142.5
48.7
125.8
63.0
49.1
100.0
50.0
97.0
110.0
39.50
33-55
1-2
21.7
20.8
4.2
9.9
10.2
4.0
8.2
8.4
6.0
6.5
1,340
1,170
1,230
1,120
127
49
60.5
65
21
65.5
0.0
0.7
328.1
28.0
92.9
255.8
13-7
478.9
139.6
70.6
385.8
125-3
67-3
142.6
61.6
53-2
104.8
55.5
187.0
217.0
51.53
40.65
II-l
22.1
23.0
5-5
12.6
9.3
5.2
7-6
6.7
6.0
6.3
1,177
973
1,077
923
92
36
58.4
52
18
63.0
0.0
0.4
224.8
26.7
89-3
192.3
26.7
521.7
161.6
67.2
370.5
120.8
56.2
12-6.1
65-4
48.1
92.8
52.8
234.0
284.0
55-90
43-33
II-2
23-5
24.7
5.3
11.6
9.4
5.7
7.8
6.5
6.1
6.4
850
780
780
760
97
45
53-3
58
22
61.7
0.0
1.2
270.6
13.1
95.2
213.8
9.6
535.3
159.3
70.2
416.0
128.3
69-2
131.9
66.1
50.4
104.7
53-7
;
54.04
53-65
III-A
22.3
24.1
6.0
18.3
8.9
6.8
7.4
6.6
6.1
6.3
805
625
750
605
58
19
67-5
43
12
72.1
0.0
1.5 -
242.6
10.7
95.6
199-7
6.7
368.3
99-3
73.0
360.0
97.0
73.1
92.0
43-3
52.8
84.0
42.0
13.0
21.0
. 61.27
58.63
III-l
23.0
23.9
5-8
21.6
8.4
7.1
7.6
6.7
6.2
6.4

—
75
12
83.6
51
7
86.3
0.0
1.0
194.4
7.6
96.1
172.5
6.8
364-8
95.5
73-8
267.0
86.5
67.6
102.3
45.3
55.8
73-0
33-0
~"
32.34
25.59
                              119

-------

Ammonia I
Nitrogen mg/1
Albuminoid I
Nitrogen mg/1
£j
Nitrite I
Nitrogen mg/1
E
Nitrate I
Nitrogen mg/1
rj
Total I
Phosphorus mg/1
b
No. of Coliform I
Colonies
colonies/ml
Aoc.
2.90
18.86
39.29
3.19
0.55
0.62
0.05
0.04
2.37
1.03
104,000
11,000
1-1
3.13
22.17
16.76
5-30
0.79
0.62
0.09
o:oe
2.71
1.31
51,000
6,700
1-2
12.31
25.43
19.05
3-29
0.93
0/67
0.04
0.04
7.56
6.24
27,000
1,800
II-l
8. -16
26.11
33.70 -
3-67
1.08
0.93
0.18
0.14
4.67
3.83
19,800
1,900
II-2
10.16
42.45
22.51
2.60
0.27
0.30
0.07
0.07
2.92
2.29
25,000
840
III-A
10.87
42.40
50.37
16.23
0.41
0.59
0.04
0.06
3.28
2.51
55,000
3,200
III-l
6.44
16.64
25.90
8.95
0.11
0.08
0.02
0.02
2.54
1.64
160,000
3,300
Legend:
   Ace	Acclimation
   A 	 Acclimation
   I 	 Inflow
   E 	 Effluent
   Rem %	Removal %
                                    120

-------
          Table 11-10   Results of Activated Sludge Examination

Suspended I" ML
Solids mg/1 I RS
Volatile /. f ML
Matter ^/l {
v ItO
Ratio VSS/SS ML
SV % fffi
LRS
S V- I ML
Sludge Age day ML

Dissolved <
Oxygen mg/1



Oxygen Uptake
Rate mg/l-hr '

"AT 1
AT 2
AT 3
AT 4
.A AT
'AT 1
AT 2
AT 3
-AT 4
Sludge Preoip. ML
Rate om/min

Aco.
5,156
17,855
3,668
12,846
73.5
45
96
91
7.7
6.0
7.9
9.0
9.4
8.1
23
29
40
31
1.00
Exp I
1
5,539
20,971
3,692
14,307
66.7
38
97
69
7.6
6.0
7.2
7.8
8.3
7.3
65
49
39
31
1.48
2
6,472
22,110
4,210
14,414
65.1
35
95
54
7.0
6.0
6.6
8.4
8.6
7.3
46
49
48
41
1.80
Exp II
1
6,480
28,417
4,339
19,061
67.2
29
96
44
8.6
5-3
6.0
7.2
7.8
6.6
62
60
62
50
2.98
2 j
6,437
35,299
4,348
23,813
67.5
25
98
38
10.6
5.5
6.1
7.8
9.2
7.2
53
52
51
44
3-53
Exp III
A
5,739
35,866
4,054
25,272
70.6
21
97
37
12.4
5.8
6.4
7.9
9.0
7.3
51
60
48
41
4.11
1
5,784
28,012
4,136
20,047
71.5
23
97
39
8.0
5.7
6.3
8.2
9-3
7.4
51
52
50
48
3-59
Legend:
    Ace.  & A
    ML 	
    RS ......
    SV '	
    AT	
    A AT	
Acclimation
Mixed Liquor
Return Sludge
Volume of Sludge Settled in 30 Min.
Aeration Tank
Average in Aeration Tank
                                   121

-------
    (l)  BOD
         As shown by Figures II-3 and II-4,  if  only the Route B sewage
         is aerated for 3 hours and its BOD-SS  load is 0.3 kg/SSkg-day
         or over, the BOD removal largely fluctuates and BOD in the
         effluent exceeds 20 mg/1.  If it is aerated for 3-8 hours and
         its BOD-SS load is 0.5 kg/SSkg-day, the  result is satisfactory
         as its BOD removal is 90$ up and BOD in  the effluent is less
         than 20 mg/1.
Fig. II-3  Relation between BOD-SS
           Load and BOD Removal
Fig. II-4  Relation between  BOD-SS
           Load and BOD in the
           Effluent
    95
            XX
                  X * X  X
                    »
          •..  *   .   •
  90

  80
  70
 ,60

H
cti
O
a
s
e85
o
m
i,



• ft
• §40
• -p
P!
§30
• Exp. II-l £
CH
xExp. II-2 H20
/
A
• •

1
10


80 	 1 	 1_ 	 L. .. i. i« .. .j n

-

•
• .*

••
• •• *x * *
X w • A
»«k x**
X, X «* •• X^ X
x><

I 1 1 1 1 i
         0.1   0.2   0.3   0.4   0.5   0.6
          -BOD-SS Load (kg/SSkg-day)
                                                             • Exp.  II-l
                                                             * Exp.  II-2
   '0  0.1   0.2   0.3   0.4   0.5  0.6
          BOD-SS Load (kg/SSkg'day)
                                 122

-------
As shown by Figures II-5 and II-6, the combined treatment of
the ordinary municipal sewage and Route B sewage brings about
a very stable, efficient result.  In case that the aeration
period is 2.5 hours and that the BOD-SS load is. in a wide range
of 0.1 to 0.5 kg/SSkg-day, the BOD removal is 95$ up and BOD in
the effluent is less than 20 mg/1.
In other words, if only the high load sewage of Route B is
treated by the pure oxygen aeration process so as to purify
the effluent to the degree of the discharge water quality
standard at the peak of the worst inflow, it requires approxi-
mately 3 hour aeration,  (in this case, aeration period on the
average flow is J.8 hours.)  If, however, the ordinary municipal
sewage is mixed with Route B sewage in the even ratio, the
aeration period on the average flow can be shortened to 2.5
hours or less.  Further it is found by the experiment that the
BOD-SS load should range from 0.2 to 0.4 kg/SSkg-day for the
most stable, efficient treatment.
When the temperature of the sewage is high, SVI goes down to
40 or so and the  return sludge suspended solids reaches 30,000
to 38,000 mg/1 and further MLSS can be maintained as high as
6,000 to 7,000 mg/1.
                              123

-------
Fig. II-5  Relation between BOD-SS   Fig. I1-6
           Load and BOD Removal
    Relation between BOD-SS
    Load and BOD in the
    Effluent
98






95

^5?
s^-x

i — i
cd
^
o
§
P=!

P
m
!

on
-
X
• X
x x
" X *• ••
x * • <
S3 20
9
x
n
0
x w
-p
s
0}
^ 10
^H
- H
• Exp. III-l
. xExp. III-A




-


x


•
X

r XX
X XV
X • • •
0
• • • •
• Exp. III-l
xExp. III-A
1 1 1 1 1 1
i i i i i~ -i n n 1 mmn/inKHR
            0.1   0.2   0.3   0.4   0.5  0.6
           * BOD-SS Load (kg/SSkg-day)
—•-BOD-SS Load (kg/SSkg-day)
    (2)  S S
         As shown by Figure II-7, in case that only Route B sewage is
         treated, the SS removal largely fluctuates between 20 and 90$
         and is quite unstable disregarding the BOD-SS load.  As shown
         by Figure II-8, however, in case that the municipal and Route
         B sewage are mixed, the result is stable with the removal
         being 75$ and over and SS in the effluent being less than
         20 mg/1.
                                 124

-------
   a
   820h
     10
     0
           X
           •
Pig. II-7  Relation  between BOD-SS
           Load and  SS  Removal
100
 90
 80
 70
 60
 50
                   X .
                   ••• .

                 .
                 x
                  • Exp.  II-l
                  * Exp.  H-2
Fig. II-8  Relation between  BOD-SS
           Load and SS Removal
    100
     90
       0   0.1   0.2   0.3   0.4   0.5  a 6
       —-BOD-SS Load (kg/SSkg• day)
                                            60
                                            50
                                            40
                                                        • Exp. III-l
                                                        x Exp. III-A
                                             ot
                                              0   0.1    0.2  0.3   0.4   0.5  0.6
                                              —» BOD-SS Load (kg/SSkg•day)
     (3)   Consumption of Oxygen
          To remove 1 kg of BOD, 1.0 to 2.0 kg of oxygen  is  required.
          Compared with the treatment of ordinary municipal  sewage,  this
          amount of oxygen is fairly big.  As for 'the  relation  between DO
          in mixed liquor and the treatment efficiency, if the  DO  at
          the 1st section of the aeration tank is low  and that  of  the
          4th section is high, the treatment is done efficiently,  but
          if the DO of the 1st section is as stipulated and  that of  the
          4th section lowers, the treatment deteriorates.
                                    125

-------
(4)  Characteristics of Activated Sludge
     The flock of activated sludge is microscopic and the zoogloea
     that forms the flock does not branch out but is spherical.
     When the sludge shows a good precipitation,  the SVI is around
     40 and the sludge precipitation rate is as big as 3.0 to 4.0
     cm/min,  and the return sludge suspended solids is as high as
     30,000 to 38,000 mg/1.
(5)  Production of Excess Sludge
     The production of excess sludge solids is 0.38 kg per 1 kg of
     removed  BOD and 68^ of it is volatile solids.   The amount of
     sludge solids is 87g per 1 cubic meter of the  sewage treated
     on the average.   Usually the volume of sludge  with moisture is
     0.34^ of the sewage treated.   At the ordinary  air system it is
     said to  be ifo but by this process it is only 1/3.
                                126

-------
III.   Conclusion
      Through, various experiments, which were conducted to treat Route
      B sewage to the degree of discharge water quality standard, the
      following differences were made clear between the pure oxygen
      aeration process and the ordinary air system.
    l)  The ordinary air system requires 10 hours of aeration period and
        over (by the two stage treatment process it is 7 hours), while
        the pure exygen process requires only 4 hours.
    2)  The BOD-SS load is 0.15 kg/SSkg-day for the ordinary air system,
        the same is 0.2 to 0.4 kg/SSkg-day for the pure oxygen process.
    3)  The air supplied is approximately 15 m3 air/m3 sewage at the
        ordinary air system, while at the pure oxygen aeration process
        the amount of oxygen consumed for the removal of 1 kg of BOD is
        1.0 to 2.0 kg.  Consequently, compared with the ordinary air
        system, the pure oxygen process.
        (a)  well removes BOD at the higher BOD-SS load, and
        (b)  produces less excess sludge.

      Therefore, it is now evident that the pure oxygen aeration process
      in quite useful for the treatment of the highly polluted sewage with
      a largely variable load, such as the one inflowing to Kisshoin Sewage
      Treatment Plant of Kyoto.
                                    127

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                                   Third US/JAPAN Conference
STUDIES  ON ADVANCED  WASTE  TREATMENT
                       presented by
                   Dr. Mamorii Kashiwaya
                Chief, Water Quality Section
               Public Works Research Institute
                  Ministry of  Construction
                          and
                     Dr. Shoichi Nanbu
              Head, Sanitary Engineering  Division
               National Public Health Institute
               Ministry of Health and Welfare
                 February 12-16,  1974
                Ministry of  Construction
                  Japanese Government

                         128

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                STUDIES ON ADVANCED ¥ASTE TREATMENT



                               CONTENTS
                                                              Page

1.    Laboratory Tests 	   130

2.    Yokosuka Pilot Plant Studies 	   1^1

J.    Kyoto Pilot Plant Studies 	   157

4.    Evaluation of Treatability Depending Upon Water
     Quality Matrices 	   175
                              129

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1.   Laboratory tests
 1.1  Lime precipitation in municipal wastewater
      At the Second U.S. -Japan Conference on Sewage Treatment Technology
      held in Washington,  B.C. and Cincinnati,  Ohio in 1972, some of the
      results of laboratory test concerning with lime precipitation in
      municipal waste water along with an outline of a pilot plant
      installed at the Shita-machi Sewage Treatment Plant in Yokosuka
      and some of pilot-scale investigation results were reported.
      These results are briefed as follows:
      a.  In pH of wastewater was raised up more than 10.5 by lime dose,
          the concentration of total phosphorus in the supernatant could
          be reduced to lower than 0.5 mg/1 regardless the wastewater,
          that is, raw sewage, primary or secondary effluent.
      b.  The lime dose required to raise pH of the wastewater more than
          11.0 was as shown in Table 1.1.
      c.  The effects of the reduction of phosphorus by lime precipi-
          tation on the concentration of magnesium in wastewater were
          as follows;
          While the reduction of metaphosphate  depended on the reduction
          of magnesium hydroxide, the reduction of orthophosphate was
          not related to the reduction of magnesium hydroxide.
      d.  Using an X-ray diffraction method,  it was disclosed that the
          final products of calcium and phosphate reaction in lime pre-
          cipitation process are calcium hydroxylapatite  Ca
          Scales of calcium carbonete  sampled from inside of some tanks
          at the Yokosuka pilot plant  was identified by both electronic
          microscopy and X-ray diffractmetry to be a mixture of aragonite
          and calcite.   These  scales assumed a slab form on the inside
          wall and a granular  shape  on the water in the tanks.
                                  130

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The Ministry of Construction gave birth to a project  team compris-
ing engineers of eight municipalities which are considered  to
implement the advanced waste treatment of their own municipal waste-
water in the future.  It is called "Joint Working Group on  Advanced
Wastewater Treatment Technology" and undertakes the collection and
exchange of information, laboratory and pilot plant tests data
gathering and discussion among members over findings.  From Tokyo
Metropolitan Government, Yokohama City, Nagoya City,  Kyoto  City,
Nagoya City, Kyoto City, Osaka City, Kobe City, Kita-kyushu City
and Yokosuka City have come two engineers each to participate in
JWGAWTT.  From April, 197-2 to March, 1973, participate in JWGAWTT.
From April, 1972 to March, 1973, the project team members had
been mostly involved in laboratory tests of lime precipitation
using primary influent and secondary effluent of their own  facilities.
During this one-year period, the laboraty tests were  conducted twice
- one in Summer and one in Winter.  In the laboratory tests, the
conditions were normalized that the flush mixing was  set at 150 rpm
for 5 min., flocculation at 30 rpm for 25 min. and the settling for
30 min.
The results of analyses of the samples subjected to the laboratory
tests are given in Tables 1.2 and 1.3-
As will be clear from tables, the concentration of total phoshorus
in the primary influent was in the range of 1.34 mg/1 to 69.8 rug/I,
while 80 per cent of the samples of influent showed a concentration
of total phosphorus of less than 10 mg/1.  On the other hand, the
concentration of total phosphorus in the secondary effluents ranged
from 0.37 mg/1 to 5-38 mg/1, whereas 72 per cent of the samples
of the secondary effluents showed a concentration of  total  phosphorus
of-not more than 1 mg/1.  These values are by far lesser than those
reported in the United States.
The test results are summarized below:
a.  All of the samples consisting of primary influents and  secondary
    effluents were normalized to have a pH value of 10.9 to 11.5
                                131

-------
before precipitation.  In this case, 43 per cent of the samples
less than 0.4 mg/1 of total phosphorus concentfation in the
supernatant.  On the other hand, the concentration of total
dissolved, phosphorus in the supernatant obtained from 68 per
cent of the samples was less than 0.4 mg/1.
In the tests, there were found no definite relationship between
the concentration of total phosphorus in the samples and the
concentration of total phosphorus and total dissolved phosphorus
in the supernatants.
The concentration of total phosphorus and the concentration of
total dissolved phosphorus, both in the supernatant were com-
pared to each other by the same treatment facilities.
It was disclosed that the lime-precipitated secondary effluent
generally showed lower concentration in both total phosphorus
and total dissolved phosphorus than the limeprecipitated primary
influent.  (As regards the total phosphorus, 13 out of 18
samples showed lower values, and as regards total dissolved
phosphorus, 14 out of 15 samples showed lower values.)
Thus, it was concluded that in order to reduce the concentration
of total phosphorus the lime precipitation of the secondary
effluent should be preceded by biological treatment of the
primary influent.  (See Table 1.4)
The concentration of total phosphorus and the concentration
of the total dissolved phosphorus, both in the supernatant,
were compared to each other by treatment plant and by season.
The comparative study revealed that the tests conducted in the
summer when water temperature is high goes a long way toward
reducing the concentration of both the total phosphorus and
total dissolved phosphorus rather than the tests in the winter
when water temperature is low.
(As regards the total phosphorus, 13 out of 18 samples showed
lower values, and as regards the total dissolved phosphorus
15 out of 18 samples showed lower values.) (See Table 1.5)
                            132

-------
d.  It was also made clear that the lime dose was necessary to raise
    pH of the primary influent and secondary effluent up to 11.0
    changes with the buffer capacity of wastewater samples.
    M-alkalinity of the samples was 50 to 200 mg/1, and the lime
    dose required was 100 to 400 mg/1.
e.  Primary influent and secondary effluent showed a magnesium
    concentration of not more than 60 mg/1.  The magnesium in
    wastewater could be transformed into magnesium hydroxide by
    adjusting the samples' pH up to 11.0.
    Magnesium hydroxide affected as a flocculation aid, achieving
    a substantive result in removing total suspended phosphorus
    in lime-precipitated supernatant.
    It was found that the residue of the total suspended phosphorus
    in lime-precipitated supernatant is related to the concentra-
    tion of magnesium hydoroxide produced.
f.  Lime-precipitated sludge being rich with magnesium hydroxide
    presents a low settleability, and increases its volume.
    (See Fig. l.l)
g.  The increase in pH is depressed by the increase in magnesium
    concentration in wastewater.
    In order to carry out lime precipitation of wastewater contain-
    ing much magnesium, the lime dose should be enough to cover
    up OH  which is required for the conversion of magnesium-ion
    into magnesium hydroxide.
h.  Increase in calcium concentration in wastewater due to lime
    dosage varied largely in the range of 20 to 140 mg/1.  (lime
    dose:  400 mg/1)
    This increase had a  correlation with M-alkalinity in waste-
    water; the higher the M-alkalinity was, the lower the increase
    in calcium in the supernatant resulted.
                                133

-------
     i.  The reduction of organic matter in wastewater by lime precipi-
         tation was 30 to 70$ for the primary influent and 20 to 50$
         for the secondary effluent, both in EMh04-COD(CODMn) index.
1.2  Investigations now in progress
     a.  Chemical precipitation of municipal wastewater by metal salts.
         JWGAWTT and the Public Works Research Institute are carrying
         cut some laboratory tests of chemical precipitation of'removing
         phosphorus, suspended solids and organic matter by making dose
         of three kinds of coagulant - aluminum sulfate, ferric chloride
         and a mixture of aluminum salt and ferric salt (which is avail-
         able on market and costs less than aluminum sulfate).
     b.  Reduction of ammoniacal nitrogen by break-point chlorination.
         In the search for the design criteria of a break-point chlori-
         nation process to be built in the Kyoto advanced waste treat-
         ment pilot plant, the experimental work has been pushed forward.
1.3  Aspects of future studies
     a.  With a laboratory lime recalcining furnace installed at the
         Public Works Research Institute,  experimental investigations
         will be conducted as to recovery and reuse of dewatered lime-
         precipitated sludge.  This furnace will be a modification of
         a multiple hearth furnace of which only a single hearth is
         taken out.
     b.  Also,  the same furnace will be used for the regeneration of
         exhausted granular activated carbon laboratory test.
     c.  Fundamental investigations on reverse osmosis are planned to
         be carried out by making use of a flat plate type laboratory
         use reverse osmotic equipment.
     d.  For the reduction of phosphate and nitrate in wastewater,
         ion-exchange method will be examined.
                                 134

-------
Table 1.1   Lime Dosage to raise pH up to 11.0




                                       ing I'1 as Ca(OH)2
Item
Range
Average
Raw Sewage with
Digester
Supernatant
172 ~ 396
293
Raw
Sewage
135 - 450
323
Primary Sedi-
mentation
Tank Effluent
146 ~ 401
255
Secondary
Sedimentation
Tank Effluent
146 ~ 296
235
                     135

-------
           Table  1.2  Primary Influent Quality Subject  to  the  Laboratory Tests
Season
Summer
Winter
City
Tokyo
Yokohama
Yokosuka
Hagoya
Kyoto
Osaka
Kobe
Kita-Kyusyu
Plant
Ochiai
Chubu
Hokubu
Uwa-Machi
Shita-Machi
Meijo
Chitose
Toba
Kisshoin
Nakahama-
Nishi
Sumiyoshi
Chubu
Higashinada
Hiakari
Kogozaki
Mean
Range
Tokyo
Yokohama
Yokosuka
Nagoya
Kyoto
Osaka
Kobe
Kita-Kyusyu
Ochiai
Chubu
Shita-Machi
Meijo
Toba
Hakahama-
Nishi
Sumiyoshi
Chubu
Hiakari
Kogozaki
Mean
Range
Mean
Range
¥ater
Temper-
ature
(°c)
18.9
21.5
21.5
22.0
22.6
22.0
21.0
23.5
23-3
23-0
23.8
23-2
23-5
22.7
22.0
22.3
18. 9~
23.8
10.0
15.6
15-0
12.5
14.3
15.3
16.0
13.8
14.0
13-7
14.1
10.8-
16.8
-
-
pH
7.50
7.39
7.20
7-40
7.25
7-14
7.00
7-31
7.37
6.90
7.28
8.34
7.30
7.40
6.95
7.32
6.90-
8.34
7.45
7.70
7.67
8.40
7-52
7.28
7.30
7.60
8.55
7.16
7.66
7.16-
8.40
7.46
6.90-
8.40
P
(mg/l)
4.46
4.18
2.18
1.84
3-98
8.59
4.33
3-23
2.61
10.0
26.9
7.90
5-30
23-3
4.02
7.52
1.84-
26.9
5-49
4.68
1.93
10.0
1-34
9.80
69.8
9.80
6.84
4-30
12.4
1.34-
69.8
9-47
1.34-
69.8
P.D
(mg/l)
4.10
2.92
0.160
1.02
2.60
6.85
1.57
2.12
2.06
2.66
2.13
5.60
3-40
3.26
2.61
2.87
0.160-
6.85
4-56
3.88
1.77
9.76
1.12
3-30
3.18
7.55
1.15
0.900
3-72
0.900-
9.76
3.21
0.160
9-76
CODun
(mg/l)
85.0
43-3
37.7
45.1
77.0
77.5
34-2
74.1
53-4
106
170
109
62.6
445
46.6
97.8
34.2-
445
143
57.0
22.0
144
53-3
115
322
212
148
248
146
22.0-
322
117
22.0-
445
1)
Tur-
bidity
(mg/l)
111
116
71.1
22.0
62.0
396
50.0
-

272
975
260
90.0
1,300
85.0
293
50.0-
1,300
170
268
50.5
540

343
1,824
200
750
1,800
661
50.5-
1,824
444
50.0-
1,824
Ca
(mg/l)
27.2
38.5
44.0
34-0
140
20.0
70.0
29-4
24.7
49-0
48.5
41.0
36.3
54-4
39-5
46.4-
20.0-
140
14.9
31.0
-
9.6

14.8
39.9
24.5
41.0
22.0
24.7
9.6-
41.0
38.9
9.6-
140
Mg
(mg/l)
8.5
43-0
12.0
23-1
382
42.7
96.0
9.2
7.4
4.9
15-2
67.0
46.4
43-7
13.8
54-3
4.9-
382
12.7
30.7
-
6.1
-
5.8
30.1
21.7
41.9
9.30
19-8
5.8-
41.9
42.3
4.9-
382
Ill-
Alkali-
nity
(mg/l)
135
141
154
111
98.5
113
132
81.5
124
87.5
144
20.1
174
243
155
128
20.1-
243
90.5
148
57
220
168
86.0
197
181
198
151
150
57-
220
137
20.1-
243
l)  Turbidity  in mg-kaoline/1




*   Samples  collected at 9:30 a.m.
                                      136

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        Table-1.3  Secondary Effluent Quality Subject to the Laboratory Tests
Season
Summer
Winter
City
Tokyo
Yokohama
Yokosuka
Nagoya
Kyoto
Osaka
Kobe
Kita-Kyusyu
Plant
Ochiai
Chubu
Hokubu
Uwa-Machi
Shita-Machi
Meijo
Chitose
Toba
Kisshoin
Nakahama-
Nishi
Sumiyoshi
Chubu
Higashinada
Hiakari
Kogozaki
Mean
Range
Tokyo
Yokohama
Yokosuka
Nagoya
Kyoto
Osaka
Kobe
Kita-Kyusyu
Ochiai
Chubu
Shita-Machi
Meijo
Toba
Nakahama-
Nishi
Sumiyoshi
Chubu
Hiakari
Kogozaki
Mean
Range
Mean
Range
Water
Temper-
ature
(°c)
20.3
22.2
22.0
22.5
22.0
21.5
21.0
23.6
23.3
23.0
23.7
24.9
23.8
22.9
21.3
22.5
20.3-
24.9
16.3
14.5
15.8
13.6
14-7
14.5
13.8
17.1
12.6
14.6
14.3
11.3-
17.1
-
-
pH
7.00
7. '05
7.30
7.40
7.35
7.21
7.10
7.55
7,82
6.80
7.31
6.88
7.80
7.03
7.00
7.24
6.80-
7.82
7.31
7.50
7.08
7.00
7.05
7-38
7.52
7.00
7-30
7.13
7.27
7.00-
7.52
7-25
6.80-
7.82
P
(mg/1)
0.780
1.04
1-43
0.450
0.756
1.47
0.260
0.480
0.548
1.33
0.950
5.38
3-38
2.90
1.62
1.52
0.260-
5.38
0.370
2.60
0.713
4.16
0.969
3.23
0.322
3.06
0.859
1.62
1.79
0.370
4.16
1.63
0.260-
5.38
P.D
(mg/1)
0.670
0.955
1-34
0.389
0.679
0.718
0.240
0.480
0.350
0.888
0.320
4.28
2.60
2.74
1.42
1.20
0.240-
4.28
0.281
2.40
0.690
3.60
0.908
2.28
0.119
2.86
0.782
1.40
1.53
0.119-
3.60
1-33
0.119-
4.28
CODMn
(mg/1)
16.5
5-5
6.8
3-5
7.4
25-3
8.2
14.0
36.8
16.8
17.3
32.8
17.6
5.3
5.0
14.6
3-5-
36.8
11.0
9-9
4.8
23.6
22.8
20.4
14.3
21.9
11.3
11.9
15.2
4.8-
23.6
14.8
3.5-
36.8
1)
Tur-
bidity
(mg/1)
-
4.4
3.1
1.9
1.4
46.4
3.0


21.5
30.6
40.0
14.0
15.0
7.5
15.7
1.9-
46.4
11.0
11.0
2.5
50.8
-
26.3
17.8
20.0
15.2
21.2
19.5
2.5-
50.0
17.3
1.9-
50.8
Ca
(mg/l)
25.6
40.0
31-3
30.0
156
12.8
76.0
26.9
23-3
22.0
48.5
52.6
34-3
60.0
30.2
44-6
12.8-
156
15.3
35-3
-
-
-
16.7
40.8
25.1
68.1
20.4
31.7
15.3-
68.1
40.1
12.8-
156
Mg
(mg/1)
5.8
34-0
10.0
12.2
484
17.0
161
8.4
8.1
3-4
17.4
115
28.4
31.6
7.2
62.9
3-4-
484
10.6
37-3
-

-
2.9
30.4
32.8
33-3
9.9
22.5
2.9-
37.3
50.0
2.9-
484
M-
Alkali-
nity
(mg/l)
99-0
72.3
65.0
74.0
97.0
83.0
100
77.3
89.9
75-0
169
77-3
186
83.0
38.0
92.4
38.0-
186
83-5
97.5
39.5
147
166
81.0
123
168
213
105
122
39-5-
213
104
38.0-
213
l)  Turbidity in mg-kaoline/1




*   Samples collected  at 9 = 30 a.m
                                       137

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        Table 1.4  Phosphorus and  Dissolved Phosphorus in the Lime
                   Coagulated Supernatants of  Primary Influent and
                   Secondary Effluent   (Summer Samples)
Plant
Ochiai
Chubu
( Yokohama )
Hokubu
Dwa-Machi

Shita-Machi
Meijo
Chitose
Toba
Kisshoin
Wakahama-Ni shi
Sumiyoshi
Chubu (Kobe)
Higashinada
Hiakari
Kogozaki
PH
11.70
11.70
11.00
10.80
11.41
11.30
11.51
11.42
11.21
10.65
11.71
11.66
10.9
10.5
12,22
12.25
12.16
12.02
11.3
11.2
11.41
11.04
11.44
11.14
!!•. 62
11.42
10.52
10.24
11.45
11.40
Ca(OH)2
(mg/l)
400
400
400
200
400
300
400
400
400
400
400
400
400
400
400
400
400
400
400
400
400
300
400
300
400
400
400
100
400
200
P
(mg/l)
0.25
0.07
0.052
0.030
0.062
0.041
0.100
0.059
0.164
0.033
0.870
0.278
0.20
0.090
0.350
0.201
0-770
0.195
0.72
0.25
0.66
0.023
0.148
0.067
0.095
0.132
0.822
0.456
0.208
0.248
P.D
(mg/l)
0.13
0.02
0.020
0.008
0.028
0.010
0.052
0.024
0.137
0.017
0.160
0.222
0.11
0.09
0.165
0.152
0.205
0.090
0.50
0.14
0.50
0.07
0.141
0.041
0.066
0.030
0.254
0.104
0.164
0.040
Secondary Effluent/
Primary Influent
as P
0.28
0.58
0.66
0.59
0.20
0.32
0.45
0.57
0.25
0.35
0.03
0.45
1.39
0.55
1.19
as P.D
0.15
0.40
0.36
0.46
0.12
1.39
0.82
0.92
0.44
0.28
0.70
0.29
0.45
0.41
0.24
*  Upper figures in  colomns  :  primary influent
*  Lower figures in  colomns  :  secondary effluent
                                    138

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                                       Table  1.5  Phosphorus  and Dissolved Phosphorus in the Lime Coagulated Supernatants
                                                 of  Summer Samples and Winter Samples
Plant
Ochiai
Chubu
(Yokohama)
Shita-Machi
Mei jo
Toba
Sumiyoshi
Nakahama-Ni shi
Hiakari
Kogozaki
Primary Influent
pH
11.70
11.88
11.00
11.30
11.21
11.24
11.34
11.52
11.03
11.42
11.41
11.44
11.30
11.57
10.52
11.15
11.45
11.73
Ca(OH)2
(mg/1)
400
300
400
300
400
200
300
400
200
300
400
400
400
200
400
300
400
300
P
(mg/1)
0.25
0.310
0.052
0.28
0.164
0.408
4-21
4.16
1.45
0.806
0.66
0.945
0.72
1.81
0.822
0.323
0.208
0.409
P.D
(mg/1)
0.13
0.212
0.020
0.23
0.137
0.325
0.180
3.12
0.485
0.570
0.50
0.688
0.50
0.635
0.254
0.056
0.164
0.158
Summer/Winter
as P
0.80
0.18
0.40
1.01
1.79
0.69
0.39
2.54
0.50
as P.D
0.61
0.09
0.42
0.06
0.84
0.73
0.79
4.54
1.04
Secondary Effluent
pH
11.70
11.84
11.40
11.8
10.65
11.65
11.48
11.60
11.10
11.43
11.45
11.55
11.2
11.50
10.68
10.79
11.14
11.30
Ca(OH)2
(mg/1)
400
300
400
400
400
400
300
400
150
400
400
300
400
150
150
400
150
400
P
(mg/1)
0.07
0.093
0.008
0.03
0.033
0.068
0.340
1.680
0.284
0.580
0.05
0.053
0.25
2.120
0.205
0.091
0.840
0.045
P.D
(mg/1)
0.02
0.047
0.0
0.03
0.017
0.040
0.216
1.480
0.280
0.452
0.03
0.049
0.14
0.900
0.020
0.062
0.166
0.050
Summer/Winter
as P
0.75
0.27
0.49
0.20
0.49
0.94
0.12
2.25
18.69
as P.D
0.43
0
0.43
0.15
0.62
0.61
0.16
0.32
3.32
CO
                     *   Upper  figures  in  columns  :   Summer  samples  (mean water temp. 22.4°C)
                     *   lower  figures  in  columns  :   winter  samples  (mean water temp. 14.2°C)

-------
0
ftf)
CO
0
H
-P
-P
0
CO
o
         O
              /O
     Magnesium Concentration in Sample  (mg/l)
  Fig. 1.1  Influence of Magnesium on Sludge

            Volume and pH of Lime Treated

            Wastewater  ( Ca(OH)2 = 400 mg/l  )
                   140

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2.   Yokosuka pilot plant studies
 2.1  Operating conditions of pilot plant
      A flow diagram of the pilot plant is shown in Fig. 2.1, and its
      operating conditions are given in Table' 2.1.
      The lime dose was 300 mg/1 as hydrated lime during the period from
      June 22, 1972 to March 22, 1973 (hereinafter referred to as "A"
      series) and 1,000 mg/1 as hydrated lime during the period from
      May 9, 1973 to October 13, 1973 (hereinafter referred to as "B"
      series).
      pH of the wastewater after adjustment by lime dose was 10.45 on
      the average in "A" series and 10.95 on the average in "B" series.
 2.2  Characteristics of pilot plant influent
      Shita-machi Sewage Treatment Plant, Yokosuka, where the pilot plant
      under discussion is installed, takes in domestic sewage as well as
      wastes from marine products processing factories which use much
      seawater.  Also, seawater permeates into the sewar pipes laid along
      the coastal line.  Therefore, the influent to the treatment plant
      contains significant amount of seawater, and magnesium concentra-
      tion is relatively high.  In the lime precipitation, "this high
      concentration of magnesium restrains the rise of pH; even when as
      much as 1,000 mg/1 of hydrated lime was dosed, pH of wastewater
      after pH adjustment was 10.95 on the average.
      Yokosuka city is planning to reuse the treated effluent as industrial
      water in the future, and is in the process of investigating the
      sewer system reconstruction in order to prevent infiltration of
      seawater.
      The lime precipitation of wastewster containing much magnesium
      brings about diversified effects- due to a large amount of precipi-
      tated magnesium hydroxide as already described in Section 1.1.
      "Lime precipitation in municipal wastewater.tf
                                  141

-------
     Namely, magnesium hydroxide acts as a coagulant aid, while it retards
     the rise of pH of wastewater (see Fig. 2.2), forms light floes with
     poor settleability,  sludge thickening rate and dewaterability, and
     may cause the accumulation of magnesium in recalcined lime when lime
     is recovered.
     The concentration of magnesium in the wastewater handled by Shita-
     machi Sewage Treatment Plant is 300 to 400 mg/1 as against about
     10 mg/1 in the typical municipal wastewater in Japan.
2.3  Outline of the test  results
     Table 2.2 shows the  mean values and ranges of influent and effluent
     quality and average  removal concerning "A" and "B" series at the
     pilot plant.
     Average suspended solids concentration of the influent were 5-4 mg/1
     in "A" series and 2.6 mg/1 in "B" series.  The turbidity was 5.8
     mg/1 and 3-6 mg/1, respectively.
     On the other hand,  suspended solids and turbidity of the lime
     sedimentation tank effluent were much more than those in the in-
     fluent; namely,- the  suspended solids were 12.3 times as much in "A"
     series and 13-9 times as much in "B" series.  This is because the
     precipitates, such as calcium carbonate and magnesium hydroxide,
     could not be settled down to the level of the suspended solids of
     the influent.
     In the calcium carbonate settling tank, a considerable portion of
     suspended solids and turbidity was removed.  In "A" series, suspended
     solids and turbidity in the effluent of the calcium carbonate
     settling tank was 5-0 per cent and 7.8 per cent of those in the
     effluent of the lime sedimentation tank.
     In the dual-media filter, both suspended solids and turbidity were
     removed quite well.   It is worthwhile that the removal of suspended
     solids was almost 100 per cent for both "A" and "B" series.  The
     turbidity of the effluent of the dual-media filter was 0.3 mg-
     Kaoline/1 for "A" series and 0.08 mg-Kaoline/1 for "B" series.
                                  142

-------
The total phosphorus contents of the influent was 1.21 mg/1 for "A"
series and 1.43 mg/1 for "B" series.  The concentration of total
phosphorus of the lime sedimentation tank effluent was 0.344 mg/1
for "A" series and 0.125 mg/1 for "B" series.  pH of the lime
sedimentation tank effluent was 10.28 and 10.81 for "A" and "B"
series, respectively.
The removal of total phosphorus by lime precipitation in "A" series
was lower than that in "B" series.  The total phosphorus in the
effluent of the calcium carbonate settling tank was 0.114 mg/1 or
90.5 per cent removal in "A" series.  And the total phosphorus in
the effluent of the dual-media filter was 0.102 mg/1 and 0.04 mg/1
or 91-6 per cent and and 97.1 per cent for "A" and "B" series,
respectively.
The ratio of orthophosphate to the total phosphorus was 87 per cent
for both' "A" and "B" series so long as the pilot plant influent
was concerned.  On the contrary, the ratio of orthophosphate in the
effluent of dual-media filter was 64 per cent and 77 per cent for
"A" and "B" series, respectively.
CODcr an<* TOG in the pilot plant influent was 40.2 mg/1 and 40.4
mg/1 for "A" series and 41-9 mg/1 and 49-2 mg/1 for "B" series,
respectively.  CODcr &n(i TOG were removed little by little in each
unit process.  The over-all removal of CODQr throughout the whole
processes was 44-3 per cent and 50.0 per cent for "A" and "B" series,
respectively, and that of TOG was 25-3 per cent and 28.9 per cent,
respectively, with the result that the removal of CODQr was larger
than that of TOG.
The regression line of COD0r with respect to TOG was found as
follows,
        CODCr = 0.673 • TOG + 5-90
The correlation coefficient was 0.761.
The total nitrogen in the pilot plant influent was 7-12 mg/1 and
7.83 mg/1 for "A" and "B" series, respectively.
                                 143

-------
     The over-all removal of the total nitrogen throughout the whole
     processes was 10.8 per cent and 30-3 per cent for "A" and "B" series^
     respectively.
     The ratio of ammoniacal nitrogen (NH^-N) to the total nitrogen in
     the pilot plant influent was 19 per cent and 50 per cent for "A"
     and "B" series, respectively.   The ratio was 7.6 per cent and 36
     per cent for "A" and "B" series, respectively,  in the dual-media
     filter effluent.
     The removal of ammoniacal nitrogen by the ammonia stripping tower
     was as low as 31.6 and 39-9 per cent for "A" and "B" series,
     respectively.  This may be ascribable to the fact that the air-liquid
     ratio was as small as 700 to 2,000.  The air-liquid ratio was first
     designed to be in the range of 1,000 to 4,000 M^-air/m^'liquid,  but
     the actual head' loss in the tower exceeded the  estimated value to
     reduce it to the aforesaid value.  At the air-liquid ratios, 700
     and 1,500, the removal of ammoniacal nitrogen was 20 per cent and
     50 per cent, respectively.  The*variation of liquid temperature  was
     in the range of 15°C to 23°C,  during the period of the experiment,
     and does not seem to have significant effect on the removal of the
     ammoniacal nitrogen.
2.4  Considerations to phosphorus removal
     The mean values of total phosphorus and their standard deviations
     are related to the mean liquid temperatures of  the dual-media
     filter effluent for "A" series as shown in Fig.  2.3.
     The figure indicates that with the lime dose of 300 mg/1,  the higher
     the liquid temperature is, the lower becomes the concentration of
     the total phosphorus in the dual-media filter effluent and also
     the smaller becomes the fluctuations.
     Comparing "A" series (mean liquid temperature:   22.7°c)  with "B"
     series (mean liquid temperature:  13.0°C) in the figure, it appears
     that an increase of about 10 degrees centigrade in liquid temper-
     ature acts to reduce the total phosphorus from  0.128 mg/1 to 0.050
                                  144

-------
     mg/1 and to increase the standard deviation from 0.081 mg/1 to
     0.25. mg/1.
     In "A"  series,  where lime dose was 300 mg/1, the effects of the
     overflow rate of lime sedimentation tank and sludge recirculation
     ratio upon  the  removal of phosphorus are shown in Table 2.3.  As
     may be  seen in  Table 2.3> a lowering of the overflow rate of the
     lime sedimentation tank and the application of sludge recircutation
     not only reduce the total phosphorus in the effluent of the lime
     sedimentation tank, but also make its fluctuation smaller.
     In "B"  series,  where lime dose was 1,000 mg/1, there were little
     or no effects of the overflow rate and sludge recirculation.
     As evidenced by the comparison between "A" series and "B" series,
     the change  of lime dose from 300 mg/1 to 1,000 mg/1 resulted in the
     reduction of total phosphorus in the effluent both of the lime
     sedimentation tank and of the dual-media filter, and diminished the
     fluctuation of  the total phosphorus concentration.
2.5  Scale formation of calcium carbonate
     In this pilot plant, development of scale of calcium carbonate was
     noticed.  It spreaded from the flush mixing tank to flocculation
     tank, and was remarkable in winter rather than in summer.  Photo
     2.1 shows a formation of scale on the flush mixing tank.  'In winter,
     development of  scale was so serious that the predetermined  flow
     rate for the pilot plant operation could not maintain owing to
     resultant reduction in the cross-sectional area of a pipe connect-
     ing each tank and increase of roughness inside of the pipe.  When
     the scale development was most serious,, the predetermined flow
     rate of 9 m3/hr could be maintained only for the first 8 days
     after cleaning, with gradual decrease afterwards, and on the 16th
     day the flow rate was decreased to about 1 nK/hr.
     Table 2.4 lists the compositions of scale formed in the tanks and
     pipes of the pilot plant.  For the preparation of the table, 10
     samples were collected from the extension between the flush mixing
     tank to the ammonia stripping tower and analyzed.
                                   145

-------
     No significant difference was found in the analytical results of
     10 sample.
     CaCO^ equivalent of CaO listed in the table was 89\4 per cent,
     signifying that calcium carbonate accounted for .abou^ 90 per pent
     of scale compounds.
     In "A" series (lime dose:  300 mg/1; average pH value of ammonia
     stripping tower effluent:  10.2&; liquid temperature:  10° to
     24°C), no scale formation was noticed, except for a slight deposi-
     tion over the filler surfaces in the ammonia' stripping tower.
     In "B" series, on the other hand, scale formation in, "B" series
     (lime dose: 1,000 mg/1; average pH value of the ammonia stripping
     tower effluent:  10.81; and liquid temperature:  15° to 27°C) was
     noticeable; during 5 months of operation,  scale depbsition over
     the filler surfaces was 0..5 to 1.5 cm in thickness.
     In the lime precipitation-ammonia stripping processes, the most
     serious problems is considered the scale formation.
     Improvements taken so far for the pilot plant against scale problem
     are as follows.
     a.  Connection between tanks was changed from pipe system to open
         channel type for ease of monitoring and removing scale.
     b.  A part of the open channel was attached with a scale preventive
         device which applys feeble current and magnetic field.   Its
         functional effects are under study.
2.6  Investigations now in progress
     The Investigation now in progress are compared with those in the
     past in the following.
     a.  In the  past, powdered lime was dosed in the form of slurry,
         while at present quick lime is slaked and then dosed in the
         flush mixing tank.
     b.  In order to improve settleability in the lime precipitation
         tank, an anionic polymer is dosed as the flo'cculant aid.
                                  146

-------
    c.  Metal  salts  precipitation process is being studied in parallel
        with the  lime  precipitation process.
    d.  Granular  activated carbon adsorption contractors are provided
        following the  dual-media filter.
    e.  Capacity  of  ventilator for the  ammonia stripping tower is
        increased to increase  air-liquid  ratio up to  2,000 to 5,000.
    f.  Scale  preventive  device is installed for lime precipitation
        process.
    A part  of  the results of the experiments now under way is summarized
    in Table 2.5.
2.7 Aspects of future  studies
    The facilities and investigations planned for the future are listed
    below.
    a.  Rearrangement  of  piping to transfer metal salts precipitated
        effluent  to  one of the existing dual-media filters.
    b,  Installation of control devices which are able to regulate  lime
        and metal salts coagulants dose in response to the changes  in
        the quality  fluctuations of influent.
        The lime  dose  will be  controlled  depending on either pH or
        alkalinity in  the influent, and also metal salts will be
        controlled depending on either  concentration  of phosphate in
        influent,  pH of liquid in flush mixing tank or turbidity of
        sedimentation  tank effluent.   Control system  for the pilot
        plant  is  still undecided.
    c.  Installation of centrifuge for  sludge dewatering.   Operating
        conditions of  the centrifuge,  especially for  lime sludge
        dewatering to  separate calcium  carbonate from other compounds
        will be determined.
                                   147

-------
                            Lime
                           (Ca(OH)2)
      Influent
  (Secondary
     effluent)
                   Holding   Measuring
                    Tank        Tank
Plush Mixing Tank
Flocculation Tank
                                                                                              Sludge Holding Tank
                                                                                             Lime Sedimentation Tank
oo
       Holding
         Tank











M





pa Qnr*"i 1





nj3- T-





fn"! r)i riv
                         Ammonia
                         Stripping  Tower
                  Pump  Measuring  Recorbo-
                          Tank     nation
                                   Tank
                      Calcium    Neutralization
                      Carbonate      Tank
                      Settling
                      Tank
                                                        Effluent
                                         Holding Tank
               Dual-Media   Measuring
                 Filter       Tank
                                                                              Pig. 2.1  Plow Diagram of Yokosuka
                                                                                        Advanced ¥aste Treatment
                                                                                        Pilot Plant

-------
Table 2.1   Operation Conditions of  the  Pilot Plant
Pilot Plant Influent
Lime Sedimentation
Tank
Ammonia Stripping
Tower
Calcium Carbonate
Settling Tank
Dual-Media Filter
Secondary Effluent
Flow Rate
Overflow Rate
Detention Time
Sludge Recirculation
Ratio
Flow Rate
Hydraulic Loading
Air-liquid Ratio
Flow Rate
Overflow Rate
Detention Time
Flow Rate
Filtration Rate
6-9 m3/h
30 ~ 50 m3/m2/d
2.3 ~ 1.5 h
0 ~ 20 %
3~8.5 m3/h
60 ~ 200 ni3/in2/d
700 ~ 2000 m^.air/
m3 liquid
2.5~6 m3/h
30 ~ 80 m3/m2/d
1.8 ~ 0.62 h
2-5.5 m3/h
120 - 350 m/d
                          149

-------

                      Secondary Effluent of "0" Sewage
                      Treatment Plant;  Mg = 10.6 mg/1
                	Secondary Effluent of Shita-Machi
                      Sewage Treatment Plant;   Mg = 300 mg/1
   H2S04
                NaOH
Titration
                            geq.)
Fig. 2.2   Titration Curves for Wastewaters of  Different

           Magnesium Concentration
                          150

-------
Table 2.2   Mean
                                                                        Range of Water Quality in Each Process, and Accumulated % Removal
tn


mean
PH
range
, mean
1)
Turbidity range
(mg/i; removal^)
mean
Suspended
Solids ran«e
(mg/l) removal '
mean
(mg/l) ranse
removal ^
mean
/ , x range
(DMT/I) b ,
removal^
mean
P,ortho,
range
/ ...,,/T \ .., r-,\
W/1^ removal"^
mean
TOC
(nWl) range .
removal'' I
mean
UUi)Cr
range
1 mr-/1 1 M
^me/1' removal^
mean
(mg/l) range
removal '
mean
, , ,, range
(ms/1) ° .
removal'' '

Influent
(Secondary
Effluent)
6.96
6.90-
7-90
5.8
0.8-
33-5
-
5.4
0.4-
48.0
-
1.21
0.403-
3.21
_
-
-
-
1.05
0.503-
2.48
-
40.4
2.4-
114
-
40.2
4.0-
104
-
7.12
2.12-
11.8
-
1,36
0 -
7.41
-
(1972
lime
Sedimen-
tation
Tank
Effluent
10.28
9.30-
11.20
39.8
2.0-
510
-
66.5
8.0-
400
-
0.344
0.024-
3.28
71.5

-
-
0.352
0.026-
3.68
66.5
37.2
3.3~
94.8
7.9
38.1
4.0-
152
2.7
7.08
2.95-
12.3
0.6
1.33
0 -
6.22
2.2
A Series
.6.12 - 197
.Ammonia
Stripping
Tower
Effluent
9.90
9.20-
10.75
-
-
-
_
-
-
-
-
_
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0.91
0 -
4.35
33.1
3-3.22)
Calcium
Carbonate
Settling
Tank
Effluent.
8.43 •""•'•
6.00-
10 . 60 .-
3.1'
0.8-
20.5
46.5
3.3
0 -
22.0
38.9
0.114
0 -
0.705
90.5
-
-
-
0.075
0 -
0.353
92.9
30.2
1.4-
86.4
25.3
30.9
2.4-
99.2
23.1
-
-
-
-
-
-

Dual-
Media
Filter
Effluent
7-95
6.30-
10.50
0.3
0 -
21.0
94.8
0
0
100
0.102
0.475
91.6
-
-
-
0.073
0 -
0.394
93.0
30.2
6.2-
89.2
25.3
22.4
3.2-
60.8
44.3
63.9
6.54-
10.5
10.3
0.48
0 -
3-73
64.7

Influent
(Secondary
Effluent)
7.65
6.90-
9.15
3-6
1.5-
11.0
-
2.6
0.4-
8.2
-
1.43
0.702-
4.35
_
1.33
0.630-
2.87
-
1.24
0.450-
2.80
-
49-2
6.9~
78.9
-
41.9
13.8-
88.9
-
7.83
3-49-
9.57
_
3.89
0.51-
7.61
-
(1973
Lime
Sedimen-
tation
Tank
Effluent
10.81
10.00-
12.40
23.8
3.0-
130
-
36.1
7.0-
68.0
-
0.125
0.004-
0.696
91.3
0.102
0.006-
0.595
92.3
0.086
0.004-
0.486
93.1
39.1
14.9-
96.5
20.5
33.6
11.7-
68.9
19.8
-
-
_
4.14
1.10-
6.03
-
B Series
.5.9 ~ 1973
Ammonia
Stripping
Tower
Effluent
10.29
8.70-
12.50
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
_
2.49
0.66-
3.82
35-9
.10.13)
Calcium
Carbonate
Settling
Tank
Effluent
9.65
6.38-
11.90
6.0
0.2-
45.5
-
6.2
0 -
40.0
-
-
-
-
-
-
-
-
-
-
31.2
12.5-
58.1
36.6
24.6
9.36
42.0
41.3
-
-
_
_
-
-

Dual-
Media
Filter
Effluent
7.24
5.70-
10.90
0.08
0 -
0.65
97.8
0
0
100
0.042
0.004-
0.201
97.1
0.035
0.006-
0.178
97.4
0.027
0.002-
0.400
97.8
35.0
9-7-
70.1
28.9
21.0
6.1-
54.6
50.0
5.46
2.13-
8.15
303
1.99
0.70-
3-38
48.8
                                  l)  Unit of Turbidity is mg'kaoline/1.
                                  2)  % removal is based on influent concentration.
                                   *  M-alkalinity of influent were 92 mg/l (67-119) in "A" series and 64 mg/l (30-88) in "B" seri
                                   *  pH of wastewater after pH adjustment were 10.45 (10.01-10.81) in "A" series and 10.95 (10.00'
                                   *  MLSS in flocculation tank were 994 mg/l (106-4,180) in "A" series and 1,550 mg/l (572-3 180)
                                                                               es.
                                                                               '-12.60) in "B" series.
                                                                                in "B" series.

-------
    0,24
     a 20
     cut,
     0,12
     0.08
     0.04
             O  O
                       9 P

                       _ Standard

                           Deviation
0,08
406   JT


      a
      o
      •H
      -P
      cd


0.^4   S
      PI
0.02
                                       O
                                             CO
        /2   /4   /6   /8  20   22   24


          Water Temperature  (°C)




Fig. 2.3  Relationships  between Total Phosphorus


          in Dual-Media  Filter and its Standard


          Deviation, and Water Temperature



          ("A" series)
                        152

-------
           Table 2.3  Effects of Overflow Rate of Lime Sedimentation Tank and Sludge Recirculation Rate on Phosphorus Removal
Case
Al
A2
A3
Flow Rate
(mVh)
9
6
8
Sludge
Recircu-
lation
Ratio ($)
0
0
20
Overflow
Rate
(mVni2-cO
50
33-3
44.4
MLSS in Floccuta-
tation Tank (mg/l)
mean
750
590
1,600
range
300-1,560
140-1,440
1,140-2,460
P in Lime Sedimentation Tank
Effluent (mg/l)
mean
0.376
0.242
0.210
Standard
deviation
0.146
0.107
0.090
range
0.164-0.634
0.039-0.417
0.107-0.394
P in Dual-Media
Filter Effluent
(mg/l)
0.050
0.048
0.049
en
CO
                     *  Lime Dose  300 mg/1  ( as Ca(OE)2  )

-------
Photo 2.1
Scale on the Flush
Mixing Tank
            154

-------
             Table 2.4   Composition of Scale

Range
Mean
Ignition
Loss
45.8-47-2
46.4
2)
Impurities
0.29-1.87
0.85
CaO
44.3-51.5
49.5
MgO
2.2-6.4
3.5
Total
99-1-102.7
100.2
l)  at 1,000+;50C; includes adhesive moisture,  crystal water
    and
2)  includes Si02 and




3)  49.5$ as CaO is equivalent to 89.4$ as
                           155

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            Table 2.5   Interin  Summary for the Experiments Being Under Way

PH mean
n ^ mean^)
Turbidity1'' ,5)
removal^ '
Suspended mean^'
Solids removalS)
mean4)
removal'''
mean4)
P,ortho cl
removal J '
mean''''
TOC ,c)
removal-^ '
' COD mean*}
removal' '
mean4)
• cl
removal-1 '
Influent
(Secondary
Effluent)
7.26
5.69
_
5.8
_
1.37
-
1.17
-
28.6
-
23.4
_
4.86
-
Lime
Sedimenta-
tion
Tank
Effluent
10.40
14.5
-
34
_
0.322
76.5
0.206
82.4
20.9
26.9
21.9
6.4
5.00
-
Ammonia
Stripping
Tower
Effluent
10.06
-
.
-
_
_
-
-
-
_
-
-
_


Calcium
Carbonate
Setting
Tank
Effluent
7-70
4.70
17.3
5.6
3.4
-
-
-
-
24.5
14.3
16.6
29.1

-
Dual-Media
Filter
Effluent
7.36
0.49
91.4
0
100
0.209
84.7
-0.174
85.1
16.3
43.0
12.0
48.7
4.28
11.9
3)
Sedimenta-
tion Tank
Effluent
Treated by
A12(S04)3
6.85
5.70
-
7.6
-
0.433
68.4
0.379
67.6
22.8
20.3
19.9
15.0
3.89
20.0
l)  Unit of turbidity  is mg-kaoline/1
2)  lime dose = 300 mg/1 as Ca(OH)2
3)  mole ratio of  Al/P = 3.28
4)  mg/1
5)  %\  based on influent concentration
                                         156

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3.  Kyoto pilo't plant studies
    Advanced waste water treatment plant was partly completed at Toba
    Seawage Treatment Plant, Kyoto, in February, 1973 > and experiments
    on the down-flow filtration process have been carried out from this
    March.  The down-flow filtration process is designed to remove
    suspended solids from the conventional activated sludge process
    effluent.
    In Japan, the activated sludge process accounts for 71 per cent of
    the total number of municipal sewage treatment plants.  However, at
    the final settling tanks of the activated sludge process, organic
    suspended solids (i.e. biological floes) may not be removed enough
    from the effluent.
    For this reason, a design manual for the facilities to remove them
    has been expected to prepare quickly as possible.
    To fulfil the demand, Kyoto pilot plant began with the down-flow
    filtration process for which some information on design and maintenance
    is available from our own experience of supplying in-plant water.
  3.1  Experimental instrumentations and methods of experiments
      A pilot filter system was installed, which consists of 3 filters,
      each having and filter area of 1.2 m% a media depth adjustable in
      the range of 0.6 to 1.0 m, and a maximum filtration head adjustable
      in the range of 2.4 to 3.0 m.  The flow control is carried out by
      means of a sluice valve, and the filtration head loss is continously
      measured using an automatic level gauge.  Flow rate of effluent is
      measured continuously by a 30° V-notch weir equipped with an
      automatic level gauge.  The filter is cleaned by fixed surface
      washing and back washing.
      The cleaning wastewater is measured by means of a 90° V-notch weir
      and sampled when it is necessary.
      The filter media size used for the experiments are as listed in
      Table 3.1.  The filter media are packed as illustrated in Table
      3.2.
                                  157

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     As a first phase experiment, the effects of the ratio of anthracite
     coal depth to silica sand depth in the dual-media filter on the
     filtration efficiency and overall economics were examined by com-
     paring the filters No.l and No.2, along with a comparative study
     of filters No.2 and No.3 on the effects of the difference between
     the dual-media system and tri-media system.  For the experiments,
     a declining filtration method was used with the maxium filtration
     head set at 3.0 m.  The initial filtration flow-rate of filters
     was set at 120 m3/m2-d, 240 mVm2.d,  360 mVm2-d, 480 m3/m2-d and
     540 m3/m2'd,  respectively.
     The surface washing rate and its duration time for the fixed
     surface washing were set at 0.15 to 0.2 mVm2'min' an(i 6 "to 10 min.,
     respectively, and the expansion rate  of filter media and washing
     time for the back washing at 20 to 25 per cent and 6 to 12 min.,
     respectively.  In case the  expansion rate for the back washing was
     25 per cent,  the back washing rates of filters No.l, No.2 and
     No.3, were 0.78 mVni2• min. , 0.6? m^/m2'min• and 0.70 m3/m2•min.,
     respectively.  The fixed surface washing and back washing were
     overlapped in the time range of 1 to  7 min.
3.2  Relationships between run-length and  filtration flow-rate
     The relationships between the run-length and filtration flow-rate
     are shown in Pig. 3.1.
     The run-length of No.l filter was such less than that of filters
     No.2 and No.3.
     The run-length of filter No.2 showed  a tendency to become a  little
     longer than that of filter  No.3.  Namely, it is found that the
     thickness of  anthracite coal medium has a great influence on the
     run-length, and that the thickness of anthracite coal media  to
     total media depth governs the economics of the filter process,
     accordingly.
     In the declining filtration method used for the experiments,  the
     decline in the  filtration flow-rate was as shown in Table 3.3.
                                  158

-------
     The  decline in the filtration flow-rate with increase in the
     filtration head-loss was larger as the initial filtration flow-
     rate becomes large.   Beyond an initial filtration flow-rate of
     360  m^/m^'d, the flow-rate declined soon after the start of filtra-
     tion.   With reference to Fig. 3-3 in which the typical sewage flow
     pattern of Toba Sewage Treatment Plant is given,  the flow-rate is
     relatively constant over a period of about 9 hrs  (from 10:00 a.m.
     to 7:00 p.m.).  Prom 7:00 p.m., however, the sewage hourly flow-
     rate to the treatment plant was on the decline.   For this reason,
     if the actual treatment plant should be operated  in declining
     filtration method as in the experiments (i.e., if media size and
     depth of filter No.2 or No.3 is applied), and if  the filter should
     be washed once every day, the initial filtration  flow-rate might
     have to be selected less than 360 m^/m^-d.
3.3  Effluent quality
     The  quality of the influent and effluent of the filter is shown in
     Table 3-4-  The quality of filtrate was largely influenced by the
     quality of biological treatment effluent, making  the effects of
     filtration flow-rate uncertain.
     Filtrate quality was degraded when experiments were carried out at
     a filtration flow-rate of 480 mVm^'d.  This is because of the
     breakdown of the sewage sludge treatment facility during that
     period, which forced to accumulate sludge in the  primary sedimenta-
     tion and biological treatment facilities.
     There were differences in the quality of filtrate among the three
     filters; filter No.l was better than filters No.2 and No. 3, and
     filter No.2 was slightly inferior to filter No.3-  It was also
     found that the difference in filtrate quality among the three
     filters was noticeably increased when the initial filtration flow-
     rate was large.  But, it was inferred that the difference would be
     very little if the filtration flow-rate was lower than 360 m^/m^-d.
     When three filters applying declining filtration  method with media
                                   159

-------
     thickness set at 1.0 m and maximum filtration head at 3-0 m was
     carried out,  the change in the filtrate quality during the filtrat-
     ing period was very little.  Table 3-5 shows the above two examples.
     With all, it  is concluded that when the filtration is to be conducted
     at a filtration flow-rate of less than 360 m3/m2-d, the ratio of the
     anthracite coal layer to the total media depth be preferably around
     60 per cent,  just as in the filter system configuration preferred
     in this filters Wo.2 and No.3.  It is proved with this arrangement
     that not only can be run-length increased like the example shown
     in Fig. 3.1,  but the filtrate quality can be maintained satisfactory.
     There was no  significant difference in both run-length and filtrate
     quality between the dual-media filter No. 2 and tri-media filter
     No.3-  This may be attributable to the selection of the size of
     gannet sand used as a medium.
3.4  Organic loads by washed waste water
     The washed wastewater from the filter system is returned to inlet
     of primary sedimentation tanks of the treatment plant.  In the
     existing sewage treatment system, the loading by this washed
     wastewater cannot be ignored.  For this reason, the volume of
     washed wastewater and the loading by it were examined.  Fig.  3-2
     shows an example.
     In case the back washing was carried out with the media expansion
     ratio set at  20 to 25 per cent,  it took about 5 min.  for the filter
     No.l (with short run-length) and 7-5 to 8 min.  for the filters
     No.2 and No.3 to attain a practical refreshness.  As regards the
     example shown in Fig. 3-2,  run-length was 13 hrs for the filter
     No.l, 25 hrs  for the filter No.2 and 24 hrs for the filter No.3.
     At the time of the back washing, the maximum BOD concentration
     was 939 mg/1, 1,639 mg/1 and 1,306 mg/1 for the filters No.l, No.2
     and No.3, respectively.
     The maximum suspended solids concentration was 1,220 mg/1, 2,320
     mg/1 and 2,070 mg/1, respectively.  However, during the required
                                 160

-------
     washing time in which excess washing time was not included (5 min.
     for filter No.l; 8 min.  for filters Wo. 2 and No. 3), the mean BOD
     concentration was 28? mg/1, 410 mg/1 and 411 mg/1 for filters No.l,
     No . 2 and No. 3,  respectively.  Also, the mean suspended solids con-
     centration was 384 mg/1, 551 mg/1 and 575 mg/1, respectively.
     While the maximum BOD concentration and maximum suspended solids
     concentration were so high as above, the mean values were about 2
     to  3 times those of the  primary influent.  The washing water
     required was 5-9 to 7.6  m^/filter m2, and retio of washing water
     to  filtrate volume was less than 2.5 per , cent.
3.5  Influences of filter washed wastewater on primary sedimentation
     tank of existing facilities
     Investigations were conducted on the influences of washed waste-
     water created by once-a-day washing of the filter over the functions
     of the primary sedimentation tank of the existing facilities into
     which it would be return.  Fig. 3-3 is an example showing the
     influent load to the primary sedimentation tank of Toba Sewage
     Treatment Plant.  During the survey, the sewage influent at the
     Plant was 362 x 1CP
     The Toba Plant handles the sludge of the nearby Kisshoin Sewage
     Treatment Plant and treats supernatant coming from another anaerobic
     digestion facility which was treating night soil.   As a consequence,
     the return waste water from the plant at that time was as much as
     41 x ID? m3/d running into the primary sedimentation tanks.   The
     over-all influent of the primary sedimentation tanks was 403 x 10^
     m^/d,  and the mean surface loading of the tanks was 22.7 m-Vm^-d.
     The average removals of suspended solids and BOD were 76.5 and 59-2
     per cent respectively.  As given in Pig. 3.3, the influent load to
     the primary sedimentation tanks was more than 20 x 10^ m-Vhr
     during a 10-hr daytime, declining gradually from 7:00 p.m. to
     6:00 a.m.,  and thence increased sharply during the period from
     6:00 a.m. to 10:00 a.m.
                                   161

-------
     Both the influent suspended solids load and BOD load showed a
     tendency to decrease from midnight to early morning.
     Assuming that at Toba Plant a dual-media or tri-media filter
     system is installed and operated at a filtration flow-rate of 300
     m3/m2'd with washing once a day, the number of filters required
     will be a dozen or so.  If the filters are to be recleaned one by
     one sequentially, the washed wastewater load on the primary sedimen-
     tation tank will be equalized over some period of time.   The hatched
     part appearing in Fig. 3-3 is an example showing the case where the
     filters are washed during 2:00 a.m. to 8:00 a.m. period.  In this
     example, the overflow rate of the primary sedimentation tanks will
     be only 21.4 m^/m^-a even at 2:00 a.m. when the situation is most
     critical.  This is almost on the same level as the mean overflow
     rate of 22.8 m3/m2.£ Of the primary sedimentation tanks without
     filters.
     BOD loading and suspended solids loading are not more than 1/5  the
     mean values when filters are not installed.  Namely, the filter
     washing, if taken from midnight to early morning,  would not affect
     the existing sewage treatment facilities and could do without ex-
     pansion of the existing facilities.
     Feasibility of treating the washed wastewater in the primary
     sedimentation tank was also examined using a settling column.   The
     results revealed that suspended solids in the washed wastewater
     could satisfactorily settle out and be removed even without dosage
     of a catonic polymer as the flocculant aid. (see Fig. 3.2)
3.6  Investigations now in progress
   (l)   As described in the foregoing,  comparative studies on the three
        down-flow filters have been carried out so far.   It was reported
        that in England the up-flow filtration has been sucessfully used
        for polishing of the secondary effluent.
        To follow suit,  one Body Immedium Filter (filtration area:  1.2
        m^) was installed at this plant, and has been studied in comparison
        with other three media filters.
                                   162

-------
     The  media (silica sand)  used for the up-flow filter are in two
     layers  - one having an effective size of 1.16 mm and a uniformity
     coefficient  of 1.33 and  another having 2.01 mm and 1.31> re-
     spectively.   The  over-all media depth of the filter is 1.55 m.
     The  up-flow  filter is cleaned by air agitation and back washing.
     For  the filter washing water, the secondary effluent is used.
     As shown in  Table 3.6, the filtrate quality obtained is little
     different from that by the down-flow filters No.2 and No.3.
     But, the up-flow  filter requires twice or more time in washing
     than the down-flow filter does.  However,, the up-flow filter,
     permits to used the secondary effluent directly as the filter
     washing water, and to dispose the effluent without post aeration
     because dissolved oxygen concentration in the filtrate is
     relatively high.
(2)   At the  primary and secondary processes of large-scale sewage
     treatment plants  in Japan, where wastewater flows in from  com-
     bined sewarage systems,  phosphorus is removed more than 6C$>
     from influent of  primary sedimentation tank in which digested
     supernatant  is contained with raw sewage.  In some cases,
     removal of phosphorus in the effluent is attained more than 80fo.
     However, stringent effluent standard for phosphorus may be set
     for  sewage treatment plant effluent, and additional removal of
     phosphorus may be required.  It will therefore be of great
     necessity to find an economical way for the reduction of residual
     phosphorus in secondary effluent.
     Certain data from the United States indicate that the concentra-
     tion of phosphorus in secondary effluent is 6 mg/1 or higher in
     the  U.S., while that in Japan is 2 mg/1 or lower at large-scale
     sewage  treatment  plant at present.  Therefore, less removal
     of phosphorus from secondary effluent might be allowed in  Japan.
     Investigations are in progress as to the influences of flush
     mixing  with  coagulant addition as a pretreatment of filtration
     over the filtrability, and quality of filtered 'water and washed
                                 163

-------
     wastewater.   According to a laboratory test,  it is found that
     the method improves removal of phosphates and CODj/^.  The mole
     ratio of Al+^ to the concentration of phosphorus in secondary
     effluent, however,  is required to be 2.5  to 3 for maintaining
     the concentration in filter effluent lower than 0.5 mg/1, and
     the economical aspect of phosphorus removal should be examined
     carefully.
(3)   Since the reduction of CODjy^ is not enough when only direct
     filtration of secondary effluent is applied for an additional
     process,  experiments on, granular activated carbon adsorption
     process have  been started.   The granular  activated carbon
     adsorption system used is composed of six down-flow gravity
                                                                  f~>
     type pilot contactors each having an adsorption area of 0.7 m .
     The system is designed to be modified into three running modes
     - 1-tank 6-parallel,  2-tank 3-parallel and 3-tank 2-parallel -
     whichever is  desired.   In the experiments by  2-tank 3-parallel
     or 3-tank 2-paralleT,  the so-called merry-go-round operation is
     possible.
     The season why the  granular activated carbon  adsorption tank is
     made of the down-flow gravity type is that when this kind of
     facility  is installed in the future its main  body is expected
     to be constructed in reinforced concrete  structure.
     The effluent  of the activated carbon adsorption contactors is
     continuously  measured with a 30° V-notch  weir equipped with an
     automatic level gauge.
     For the measurement and sampling of washed waste water,  a 90°
     V-notch weir  box is installed.   The experimental facility can
     be operated semi-automatically or full automatically or manually.
     At present, 2-tank  3-parallel operating mode  is.employed,  and
     granular  activated  carbon of Calgon 8 x 30 meshes,  Calgon 12 x 40
     meshes  and  Shirasagi  8 x 30 meshes is tested.   Carbon bed depth
     is 3-0  m  for  all of the contactors..
                               164

-------
     Influent is 240 m^/m^-d, and back washing of carbon bed is
     carried out once a day.  An example of the water quality data
     is shown in Table 5-7-
3.7  Aspects of future studies
     At the pilot plant located at Toba Sewage Treatment Plant, Kyoto,
     a furnace for regeneration of exhausted granular activated
     carbon will be installed in order to test the replicate use of
     regenerated activated carbon.  Also, up-flow type granular acti-
     vated carbon adsorption contactors will be installed for the
     comparative study with the down-flow type granular activated
     carbon adsorption system.
     As regards to the ammonia removal, laboratory tests have already
     been pushed forward for the installation of a break-point
     chlorination pilot facility.  It is in the stage of design of
     the instrumentation.  In Japan, water pollution problems due to
     excess nitrogen in river and lake water and irrigation water
     have come to stay, and the development of an economical way of
     removing nitrogen has been voiced for.
     Unfortunately, however, each sewage treatment plant barely
     possess space to enlarge the facilities,  and has only a limited
     space to accommodate such extra work.  With this in mind,
     experiments of removing nitrogen are started on the break-point
     chlorination process for which space can be small.
     The soda industry here in Japan has been urged to change its
     production process from mercury process to membrane one and it
     remains uncertain whether so much chlorine gas will be avilable
     for the break-point chlorination process from now on.   Therefore,
     it is necessary to investigate nitrogen removal processes more
     extensively.
     Another facility to be installed will be ion-exchange processes
     for the removal of nitrate and phosphate, and also ammonia.
                                 165

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Table 3.1   Media Size Using Experiment
Media
Anthercite Coal
Silica Sand
Garnnet Sand
Effective
Size (mm)
1.22
0.87
0.54
Uniformity
Coeficient
1.21
1.21
1.41
Table 3.2   Media Depth  of Each Pilot Filter
^^^^^ "BH ~| f pT»
•n/r -, . ^^-^J- -1- J- wC-L
Media ^^L^^
Anthercite Coal
Silica Sand
Garnnet Sand
Total
No.l
(mm)
150
850
-
1,000
No. 2
(mm)
625
375
-
1,000
No. 3
(mm)
625
300
75
1,000
                          166

-------
Pig. 3.1
cr>
                    c\J
                     a

                     o,
                     a
                     0)
                     -p
                     cd
                     •H
                     -p
                     •H
                     a
                     M
                                       Relationship Between Initial Flow-rate and


                                       Average Run-Length  of Pilot Filters
                         240 -
                          /20
                                                                               Filter No,


                                                                               Filter No,


                                                                               Filter No.
                              O
                                       20
                                                  /OO       /2O




                                                 Run-Length  (hrs)

-------
Table 3-3   Relationship between Filtration Plow-rate
            Declined and Filtration Head-Loss
Initial
Flow-rate
(m3/m2.d)
120
240
360
480
540
Filtration Head-Loss (cm)
50
118
232
358
480
540
100
108
218
325
462
500
150
98
. 200
307
410
472
200
85
182
278
365
405
250
78
158
236
322
350
300
58
124
197
258
292
                        168

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                                     Table 3-4   Influent and Filtrate Quality of Pilot-Filters
Initial Filtration
Flow-rate (m-'/m -d)
^^~^~~^Inf luent or
^""""""---JJiltrate
Items -\^__^^
Nos. of Data
S.S.
(mg/l)
BOD
(mg/l)
CODMn
(mg/l)
max.
min.
Av.
max.
min.
Av.
max.
min.
Av.
120
Inf.
8
26.3
7.9
14-8
29.1
12.5
22.4
20.7
9.8
15.6
Filtrate
No.l
5
8.3
1.0
3-7
10.9
1.7
3-9
14-3
8.4
10.4
No. 2
8
8.1
1.2
4-0
11.2
2.1
4.1
15.1
8.4
11.4
No. 3
8
7.4
1.6
3-9
9-9
2.2
3.8
14-9
8.4
11.3
240
Inf.
9
10.8
4.6
7.5
17.9
6.0
10.9
15.7
5-4
12.2
Filtrate
No.l
8
3-7
0.5
2.2
4.0
1.9
3.2
12.8
1.0
9.8
No. 2
9
3.8
1.0
2.7
7.3
1.8
4-3
13-7
1.0
10.2
No. 3
9
3.1
1.0
2.5
6.8
2.2
4-3
13.0
1.0
9.8
360
Inf.
10
28.8
3.1
9.7
16.9
2.5
10.8
23.8
6.1
12.5
Filtrate
No.l
7
2.4
0.3
1.3
4.1
1.0
2.1
16.4
4.5
10.4
No. 2
10
3.2
0.2
1.4
3-6
1.4
2.2
16.4
4.9
10.1
No. 3
10
3-0
0.1
1.3
3-4
0.6
2.0
16.7
4.8
9.8
480
Inf.
10
67.7
5.0
22.8
32.0
4-4
18.0
28.6
8.8
16.0
Filtrate
No.l
7
29-0
0.5
6.6
7.5
1.0
2.9
17-9
5-5
9.9
No. 2
10
43-5
0.8
11.4
19-4
1.4
6.4
20.6
5.9
12.0
No. 3
10
46.5
0.7
12.0
21.0
1.3
6.3
21.5
5.4
11.9
540
Inf.
9
33-5
4.2
13.8
29.9
6.3
15-8
26.0
9-0
16.5
Filtrate
No.l
7
5.6
1-4
3-5
7.1
1.5
4.1
16.0
8.2
12.6
No. 2
9
19.0
1.2
5.4
20.2
1.3
5.6
21.2
8.1
12.8
No. 3
9
18.3
1.1
5.2
16.1
1.0
4.8
21.7
8.4
13.0
CTl

-------
Table 3.5    Comparision to Filtrate of Three Filters after Filtration Start
How-rate
U3/m2-d)
240
^~~^^^^_Influent or
^^^Jfiltrate
Items ^^^-^^
Sampling Time after
Filtration Start (hrsrmin)
Liquid Temp (°C)
Dissolved Oxygen (mg/l)
S.S.
BOD
CODMn
cone. (mg/l)
rem. (fo)
cone. (mg/l)
rem. (%)
cone. (mg/l)
rem. ($)
Inf.
2:45
24.6
0.5
8.0
-
6.2
-
10.4
-
Filtrate
No.l

25.5
0.5
3-7
53-7
3-5
43.6
9.2
11.5
No. 2
3:00
25-5
0.3
2.9
63-8
3-1
50.0
10.1
28.8
No. 3

25.5
0.3
3.1
61.2
3-3
46.8
10.4
0.0
Inf.
26:25
24.8
0.2
10.7
-
12.9
-
12.4
-
Filtrate
No.l

25.2
0.2
2.6
75.7
3-4
73-5
9.3
25.0
No. 2
27:00
25.2
0.2
3.3
69.1
3-4
73-5
9.7
21.8
No. 3

25.2
0.2
2.7
74.7
3-2
75.1
9.7
21.8
Inf.
46:25
24.5
0.4
6.4
-
12.5
-
12.6
-
Filtrate
No.l

25.0
0.2
2.8
56.6
4.0
68.0
11.2
11.1
No. 2
47:00
25.0
0.2
2.9
54.8
3-8
69-5
11.0
12.7
No. 3

25.0
0.2
2.8
56.3
3.2
74.5
9.5
24.6
480
Sampling Time after
Filtration Start (hrs:min)
Liquid Temp. (°c)
Dissolved Oxygen (mg/l)
S.S.
BOD
CODMn
cone. (mg/l)
rem. (%}
cone. (mg/l)
rem. (fo)
cone. (mg/l)
rem. (fo)
2:43
26.2
0.2
8.0
-
6-. 2
-
9.8
-
3:00
26.8
0.2
1.8
77.5
2.0
67.7
8.4
14-3
26.8
0.2
1.7
78.8
1.6
74.1
8.5
13.3
26.8
0.2
1.7
78.8
1.6
74.1
8.1
17.4
24:43
26.0
1.7
8.2
-
4.4
-
9.6
-
25:00
26.5
0.2
2.0
75.6
1.4
68.2
9.0
6.3
26.5
0.1
1.5
81.7
1.4
68.2
9.0
6.3
26.5
0.1
1.7
79.4
1.7
61.5
9.0
6.3

-------
     (a) Sewage Flow
  20-
  15-
  10
                                             Filters Washed Waste
                                              Flow
                                              2.73x10? m3
          Average Hourly Flow
          with Filter Washed WasteXFlow
                13 (P.m.)  17
                                   21
                                             1   (am.)  5
     (b) BOD Load
   15-
*5>
 i-H
 H

 nz)

 I
 o
 o
 m
                                                  Filters Washed Waste
                                                  . BOD Load
                                                    0.94x104 kg/hr ,
                 13  (p.m.) 17
                                   21
                                             1 (a.m..)   5
                                                        Time
      (o)  Influent Suspended Solids Load
   10
   5-
                                                     Filters Washed Waste
                                                     Sus. Solids  Load
                                                        1.31x103 kg/hr
                '3  (p.m)  17
                                              1  (a. m.)  5
                                                         Time
Fig. 3.3  Typical Flow and Load Pattern to Primary Sedimentation Tanks
          Assuming to be Equipped Filters, Toba Sewage Treatment Plant, Kyoto
                                        171

-------
  Pig. 3.2  Settling  Column Tests  of  Filter
            Washed Wastewater

               Column  height    2.2  m
               Column  Diameter  0.3  m
   100
o
a
Q)
PH
CO

CO
         Co:
 Washed Waste Only

 Mixed Waste of Wasted
 Waste with Raw Sewage
 (Ratio  1:10)
 Washed Waste dosed a
 Cationic Polymer
 (Dose 1 mg/l)
Initial Cone, of Suspended
Solids
           /oo
       Overflow-rate
                                         -d)
                     172

-------
         Table 3-6   Comparision to Filtrate both Down-flow
                     Filters and Up-flow Filter
^~"~~^^Inf luent or
TJ. ^^"~~^\ Filtrate
Items ^\^^
Liquid Temp. (°c)
Dissolved Oxygen
(mg/l)
Turbidity (mg/l)
S.S.
BOD
C0%n
TOG
cone, (mg/l)
red. (fo)
cone, (mg/l)
red. (%}
cone, (mg/l)
red. (%}
cone, (mg/l)
red. (%)
Influent
20.3
0.5
7.5
11.2
-
17.8
-
13.7
-
14.2
-
Filtrate
No.l
20.7
0.5
2.65
2.7
75.8
5.5
69.2
11.7
14.6
9.6
32.4
Wo. 2
20.7
0.5
2.55
3.3
71.3
7.1
60.1
10.9
20.4
11.2
21.1
No. 3
20.7
0.5
3.60
4.9
56.2
9.2
45.5
11.7
14.6
10.0
29.6
Wo. 4
20.7
6.2
3.20
3.9
65.0
8.2
54.0
11.9
13.1
10.8
23-9
Remark:   Filtration Flow-rate
         Down-flow Filter

         Up-flow Filter
240 m3/ni-d
No.l, No.2, No.3
(refer to Table 3.1 & 3.2)
No. 4
                                173

-------
       Table 3.7   Influent and Effluent Quality of Pilot Granular
                   Activated Carbon Adsorption Contactors
^^•^-^Influent or
T, ^^^^~^Eff luent
Items ^~~~^~~~~^
Liquid Temp. (°C)
Dissolved Oxygen
(mg/l)
S.S.
BOD
CODMn
Kjeldahl
Nitrogen
cone, (mg/l)
rem. (fa)
cone, (mg/l)
rem. ($)
cone, (mg/l)
rem. (fo)
cone, (mg/l)
rem. ($)
In-
fluent
18.0
9-3
3.0
-
5.3
-
11.3
-
6.3
-
Effluent
No.l
17.4
0.4
3-5
-
5.1
3.8
7-7
39.7
3.8
39.7
No. 2
17.4
1.0
1.9
36.7
5.0
5.7
4.6
59.3
3.2
49-3
No. 3
17.4
1.2
2.8
6.7
5.1
3.8
6.6
41.6
4.8
23.8
No. 4
17.4
0.7
2.3
23.3
3-8
28.3
3.5
69.0
2.4
61.9
No. 5
17-4
0.7
3.6
-
4.6
13.2
7.2
36.3
4.2
33-3
No. 6
17.4
0.6
2.4
20.0
4.3
18.9
4.8
57.5
2.4
61.9
Remark:  Arrangement of Granular Activated Carbon Adsorption Contactors
Influent
Filtrated
wastewater




Contactor
No.l
E
Contactor
No. 3
E
Contactor
No. 5
E

r
ffluer
No.l
J
ffluer
No. 2
1
ffluer
No. 5
Contactor
No. 2
it
Contactor
No. 4
it
Contactor
No. 6
it




                                             •> Effluent  (c.algon 8x32]
                                                 No. 2
                                               Effluent  [Calgon 12x40J
                                                 No. 4
                                             ^ Effluent  [Shirasagi
                                                 No. 6
                Adsorption Time in Each Contactor  :    ,15 min
                                174

-------
4.    Evaluation of treatability depending upon water quality matrices
     Connecting with the treatability of waste water,  the status of the
     impurities could be represented by three components such as the
     impurity size,  chemical property and cencentration (l), (2),  (3).
     Thus if the impurity sizes are. devided into several classes by means
     of mechanical,  optical or gel chromatographical technique,  a water
     quality matrix will be able to be established schematically as shown
     in Figure 4.1.
X. j
i\
1
2
•
•
•
•
•
n-1
n
1
Cn
C2)
•
•




Cui
2
C,2








•
•









.
•


Cu


•
•





Coli






im



•
•




*• Y
n



m-l




ow




m.
Cm







Cnnv
 Pig. 4.1  Water Quality Matrix
                                Fig. 4.2  Water Quality Conversion Matrices
                                     175

-------
   The water quality conversion matrices as shown in Figure 4.2 are
   prepared for each process of water treatment.  The indices of the
   columns and rows are the same with the water quality matrix, but the
   elements are written as the percentage of removal, fi(ij), instead of
   the concentration, C(ij), of the water quality matrixes.  If the
   concentration is greatly different from each other, different treat-
   ment process shall be proposed or the different percentages of
   removal shall be put into the matrix elements.  Thus, water quality
   conversion matrices should be shown as the three dimensional matrices
   to take the concentration effects into account.
   In these water quality conversion matrices, while no removal is
   anticipated, the element R(ijk) is zero., and for the removed part
   the element R(ijk) takes a positive value.  In one case when some
   new components such as a metabolic waste of biological treatments
   are added by the treatment, the elements become negative.  In another
   case when no water quality elements exist prior to the treatment at
   the components, basic elements to be taken into the calculation
   should be pointed out.  In addition, if the element R(ijk) cannot
   be decided independedtly, the relationship between other connected
   components should be described.
   In order to develope comprehensive technology for water quality
   management on the basis of an idea as mentioned above, the research
   project supported by Special Fund for Promoting of Multiministerial
   Research Project under the Jurisdiction of the Science and Technology
   Agency has been carried on since 1972 to 1974.  The project director
   is prof. Zenji Tambo, Hokkaido University and the grantees are The
   Institute of Public Health, Ministry of Health and Welfare and Kinki
   Regional Construction Bureau, Ministry of Construction.
4.1  Experiments for the verification of the concept
     A series of laboratory experiments and pilot plant operations were
     carried out to evaluate the feasibility of the above mentioned
     concept.  To obtain general results without falling into local
                                   176

-------
  conditions, many kinds of raw waters and treated waters in widely
  spread areas of Japan were used for the experimental works.
l)  Laboratory scale coagulation and carbon adsorption experiments
    The major purpose of those laboratory scale experiments was to
    study performance of the activated sludge process and chemical
    coagulation process together with the results of followed activated
    carbon adsorption process.  For the purpose, the following ex-
    perimental studies were carried out.
      1.  Treatment of raw sewage by combination of alum or lime
          coagulation, sedimentation, filtration, and activated
          carbon adsorption.
      2.  Treatment of the activated sludge process plant (Makomanai,
          Sapporo) effluent by combination of alum coagulation, sand
          filtration, and activated carbon adsorption.
      3.  Treatment of the activated sludge process plant (Pusiko,
          Sapporo) effluent by combination of a simple sand filtration
          without coagulation and activated carbon adsorption.
    The laboratory scale semi-continuous treatment apparatus as shown
    in Figure 4.3 consisted of a 200 liter of settling tank with
    coagulation facility, a rapid sand filter, a filtered water
    storage, and four down flow granular activated carbon columns
    in series.
waste water
                    I T
                   A
                         TJ
TJ
¥_
                                        effluent
                                                    A: Settling Tank
                                                    B: Sand Filter
                                                    C: Storage Tank
                                                    D: Carbon Beds
         Fig. 4.3  Flow diagram of laboratory scale apparatus
                                  177

-------
    Standard jar tests were used to determine the coagulant dosage.
    A coagulant was added to the settling tank, then, rapidly mixed
    for 5 minutes,  flocculated for 30 minutes, and settled for 1
    hour.  The supernatant from the tank was applied to the sand
    filter with 50 cm of sand bed at constant rate of 50 m/day.  The
    filtered water was once put into the storage tank, then fed to
    the four activated carbon columns arranged in series.  The size
    of the carbon column was 3 cm in diameter and 40 cm in length.
    Pittsburg CAL activated carbon was placed in those columns with
    25 cm depth.  The rate of the flow through the adsorption columns
    was set as 144 m/day.
    In parallel with the laboratory scale continuous adsorption ex-
    periments, batch adsorption tests were also carried out by using
    powdered activated carbon.
    The turbidity was measured by a photo-turbidimeter which was
    calibrated with standard kaolinite solution.  The total organic
    carbon (TOG) concentration was determined by a Toshiba-Beckman
    Carbonaceous Analyzer.  Sample water having organic carbon con-
    centrations below 1 to 2 mg/1 was concentrated under reduced
    pressure at the normal temperature prior to the TOG determination.
    Sometimes, the  pH of the water samples was adjusted at pH=2 and
    the samples were shaken or aerated with N2 gas so as to remove
    inorganic carbon which was apt to hinder the TOG determination.
    Ultraviolet absorbances were determined by a Hitachi 124 double
    beam spectrophotometer.   The concentrations of protein (Polin-
    Chiocalteu test), amino acids (Ninhydrin test), and carbohydrates
    (Anthrone test) were also determined for the same samples.   The
    COD and major inorganic constituents were also determined after
    the standard methods (4).
2)  Physico-chemical treatment of sulphide pulp waste water
    A physico-chemical treatment of sulphide pulp waste water from
    a pulp mill in Tomakomai, Hokkaido,  by using activated carbon
    produced from the lignin of the pulp waste water, was carried
                                 178

-------
     out to verify the applicability of the concept to the outside of
     the municipal waste water treatment.
     The flow sheet of the sulphide pulp waste water treatment processes
     and the lignin base activated carbon production from the waste
     water is shown in Figure 4-4-
PULP WASTEWATER ——> LIME CLARIFICATION 	^ BATCH OR FLUIDIZED
                 t
               Ca(OH)2
                      SETTLED LIME=LIGNIN
                      FLOG (SLUDGE)                ACTIVATION
                                                   150°-180°c
                              £	 H2S04—=* 2 hours
                       LIBERATED                       *
                                       	>• CONCENTRATION
                       LIGNIN SOLUTION           OUI\^INIBAIXUI\
  Fig. 4-4   Flow sheet of the pulp wastewater treatment and the
             production of powdered activated carbon from lignin
             of the waste water.

 3)  Pilot plant operations
     To confirm the results of the laboratory scale experiments and
     solidify the concept, two series of the same type physico-chemical
     pilot plants were constructed and operated at Soseigawa sewage
     treatment plant in Sapporo.  A series of the plants treated raw
     sewage which was pumped up from the primary settling tank over-
     flow of the Soseigawa sewage treatment plant.  Another series
     of the pilot plant treated the activated sludge process effluent
     of the sewage treatment plant for the purpose of the tertiary
     physico-chemical treatment processes with or without chemical
     coagulation process.
     A schematic flow diagram of a series of the pilot plant processes
     is shown in Figure 4-5-  The operational flow chart including
     operation conditions is written in Figure 4-6.
                                    179

-------
1




A
t





^1
i-
c


3


-\
^
I
L

^



*
t



r


r


3-
\
. \
\




















r
-if-

-»•


~1 r
_F




\
T
I1
T


J
r
JJ
r








1

T



^L


c





^








i











IL





A
B
C
D
E
F

G


                                                          Coagulant Tank
                                                          Waste Water Inflow
                                                          Rapidly Mixing  Tank
                                                          Flocculator
                                                          Sedimentation Tank
                                                          Over flow rate  0,88cm/min
                                                          Detention time  150min
                                                          Rapid Sand Filter
                                                          Filtration rate 1^0 m/d
                                                          Activated Carbon  Beds
                                                          Total depth 300 cm
                                                          I.V. lUlt m/d
                  Fig.  4.5   Flow diagram of the pilot plant
RAW SEWAGE
                                      -*ACTIVATED SLUDGE TREATMENT PLANT
ALUM COAGULATION
     I   Dosage 150 ppm

FLOCCULATION

SEDIMENTATION
     I
RAPID SAND FILTRATION
     I
ACTIVATED CARBON ADSORPTION
     I
(DIRECT PHYSICO-CHEMICAL
  TREATMENT SYSTEM)
                                                    J
   SAND FILTRATION
   ACTIVATED CARBON
   ADSORPTION
(TERTIARY TREATMENT
    WITHOUT COAGULATION)
ALUM COAGULATION
     J   Dosage 40 ppm

FLOCCULATION
     4r
SEDIMENTATION
     4
RAPID SAND FILTRATION
     4
ACTIVATED CARBON ADSORPTION
     *
(TERTIARY TREATMENT
    WITH COAGULATION)
          Fig.  4.6   Operational  flow chart  of  the  pilot  plants.



   4)  Gel chromatogram

       The impurity size distribution of  minute fractions of those

       samples  which had passed through 0.45 micron meter membrane

       filters  was determined by  a  gel filtration mainly  on a column of

       Sephadex G-15.   For  some samples,  Sephadex G-25  or G-50 was

       also used.   Those gels were  swelled for  24 hours prior to  setting

       into the columns.  The resulting slurry  of the gel was then

       poured into the  glass  columns  of 2.5  to  4 cm in  diameter and 100

       cm in length with 90 cm of the gel bed height.
                                       180

-------
      Most  water  samples  were  once  filtered by 0.45 micron meter
      membrane  filter and concentrated into suitable concentrations
      by  rotary vacuum evaporators  at the temperatures of 25 to 30°C
      before  applying to  the column.   Concentrated samples of 10 to
      30  ml were  placed at the top  of the gel beds.  Distilled water
      was introduced into the  column from the top at a constant rate
      of  flow for the elution.  The rate of flow was 20 to 50 ml/min.
      Effluent  from the column bottom was collected in the test tubes
      by  an automatic fraction collector as 10 to 20 ml of successive
      fractions.   For each fraction,  measurements were carried out for
      TOG content and 220 to 280 millimicron meters of ultraviolet
      absorbance.
      The impurity size distribution characteristics of the gel
      chromatogram were calibrated  from the elution volume of Blue
      Dextran (M.¥.  2 millions), raffinose (M.¥. 504), maltose (M.¥.
      342), glucose (M.W. 180),  ethylene glycol (M.W.  62), methanol
       (M.W. 32),  and DBS  (M.W. 349).
4.2  Results of  Experiments
   l) Results of  laboratory scale coagulation and carbon adsorption
      experiments
      The effectiveness of alum coagulation followed by carbon adsorp-
       tion  is appreciated by comparing Tables 4-2 and 4-2. .Some amount
       of  leakage  of KMnO^ COD and E250 (Absorbance at 250 millimicron
      meters) constituents are recognized when the coagulation process
      is  omitted.  Whereas, in the  case when alum coagulation process
      is  included, the leakage from the carbon bed is very scarce in
       spite of  ~a  relatively higher  raw water concentration.
                                   181

-------
 Table 4.1   Non coagulated, filtered and carbon adsorbed
             secondary effluent.
Hours of
operation
48
96
168
336
COD(KM
Filtered
4-5
5.0
4.5
5.0
nO^ ) ppm
Adsorbed
1.0
1.0
0.9
1.2
E250
Filtered
0.122
0.109
0.110
0.137

Adsorbed
0.024
0.018
0.020
0.022
 Table 4.2   Alum coagulated, filtered and carbon adsorbed
             secondary effluent.
Hours of
operation
40
88
160
358
COD (KM
Filtered
8.2
8.5
8.3
8.0
hO^) ppm
Adsorbed
0.3
0.2
0.9
0.9
E250
Filtered
0.094
0.137
0.100
0.098

Adsorbed
0.000
0.006
0.006
0.002
The gel chromatographic studies shown in Figures 4-7 and 4.8 reveal
that without coagulation there exists typical leakage of larger
size impurities in the Zones 1 and 2 in the carbon adsorption bed
effluent.   Inefficiency of activated carbon adsorption in removing
larger size impurities should be marked.
A result of physico-chemical raw domestic sewage treatment (co-
agulation, filtration, and carbon adsorption) without biological
process is shown in Figure 4.9.  There is the leakage of COD from
the very early stage of the run.  The major constituents of the
leaked COD are lower molecular weight substances such as amino
acids, low molecular fatty acids, and carbohydrates which could
be rather easily removed by biological processes.
                           182

-------
               0,8

               0-7.
               0.1
                  ZONE 7
                 30    40    SO    60    70
                               FRACTION NUMBER X 15ml

              Fig. 4»7   Gel  chromatogram of

                         secondary effluent
                    F2SO
                      O.Z
                        30   to   io    60    70
                                   FRACTION NUMBER X 15ml
         Fig. 4.8   Gel  chromatogram of carbon adsorbed
                    secondary effluent without coagulation
     1.0

     0.8

C/Co 0.6

     0.4

     0.2

      0
CARBOHYDRATE
Raw Water Cone.
  COD 122 ppm
  Carbohydrate  152 ppm

Column depth 20 cm
             2    46   8   10   12  14  16
                     Time                 hours
    Fig. 4.9   Physico-chemical treatment effluent  of
               domestic  raw sewage.
                                183

-------
       2)  Results of sulphide  pulp  waste  water treatment studies
           For the physico-chemical  treatment of sulphide pulp waste by
           using lime or alum coagulation  and the laboratory-made lignin
           waste activated  carbon adsorption, the usefulness of the above
           mentioned chromatographic characteristics are verified as follows.
           Ineffectiveness  of activated carbon adsorption and effectiveness
           of alum or lime  coagulation in  removing larger molecular substances
           are also found by the  results being shown in Figures 4.10 and 4.11.
           The treatment system connecting both of the lime coagulation and
           fluidized carbon adsorption bed in series gives a satisfactory
           removal of the lignin  content from the pulp waste water.  The
           spent lignin carbon  saturated with the wastewater contents is
           possible to be regenerated by concentrated sulphuric acid at the
           temperatures of  150  to 180°C for the reaction period of two hours.
E 260
    2.0
    1.0
   BLUE DEXTRAN
        t
                    SUPERNATANT
                            X
             t
             '.RESOLVED SEDIMEN
             \^  SOLUTION
      100  300   500  700  900   1100  1300 ml
                              ELUATE
£ 280

   4.0

  3.0

  2.0

  1.0

    0
                                                          	 PULP WASTE WATER
                                          L ntTTr. nr-vn^A*,   — ADSORPTION 5 jhin.
                                          - BLUE DEXTRAN   —-ADSORPTION 9 hrs.
                                              300   500  700  900  1100  1300. ml
                                                               ELUATE
                                                      water.  Sephadex G-50
Fig. 4.10  Gel chromatograms of       Fig. 4-11   Gel  Chromatograms of
           supernatant and resolved               pulp wastewater and
           sediment solution of lime              carbon adsorbed waste-
           coagulation.
           Sephadex G-50

   ^}  Result of pilot plant studies
       Typical gel chromatograms obtained  from the  pilot plant studies
       are shown in Figures 4-12, 4-13, 4.14,  4-15, 4.16 and 4-17.
                                        184

-------
As is seen in Figure 4-12, so called soluble impurities in the
municipal  wastewater could be divided into five groups by the
Sephadex G-15 gel chromatography by using TOG, E260, and E220
as the water quality indices.  This grouping is recognized as a
popular one by many analyses of the samples obtained from many
sewage treatment plants and natural rivers and lakes being polluted
by municipal wastewaters.
Comparison of Figure 4.12 with Figure 4.13 shows that activated
sludge treatment processes can effectively remove only a portion
of TOG which is insensitive to the ultraviolet absorbance at 260
millimicron meters, i.e., E260.  Thus, for the removal of TOG
contents corresponding to E260, activated sludge processes are
not effective.  The increase of ultraviolet absorbance at 220
millimicron meters, i.e., E220, in the Zone 4 would be caused by
some metabolic wastes of the biological activities.
Chemical coagulation followed by sedimentation and sand filtration
is effective for the removal of impurities in the Zone 1 and less
effective for smaller impurities in the Zones 2 to 5 as clearly
seen by the comparisons of Figure 4.13 with 4.14 and Figure 4-12
with 4.16.
However, a noticeable amount of TOG removal in the Zone 3 is
detected through the direct physico-chemical treatment process
as shown in Figures 4.16 and 4-17.  This phenomenon might be
caused by some biological actions in the sand bed and carbon
adsorption bed.  Incidentally, no removal in the Zone 3 is observed
in case of batch treatments using paper filters and powdered
activated carbon or short period experiments performed by small
scale laboratory tests.  The total TOG contents removed by the
activated carbon column in the pilot plant are far beyond the
saturation adsorption capacity measured by batch tests.
                               185

-------
 01
 u
o
o
fc!
                              FRACTION
                              NUMBER x 10ml
                                                                        FRACTION
                                                                        NUMBERxlOml
   Fig.  4-12  Gel chromatogram of
              raw sewage
Fig. 4.13  Gel chromatogram of
           secondary  effluent
                            i NUMBER x 10ml

-------
                0
                5
NUMBER^ iQmi  g!jj -

Zone
1
20

•

2
i ^"-J
l



3
j
\30 ,
\S^~s

\
i
i
ja!
A,!
(^ -^

1
1
1
1
1
1
1

— E 22(
--E 260
-"iRACTI
NUMBER

                                                                        x 10ml
Fig.  4-16  Gel chromatogram of
           coagulated raw sewage
           Fig.  4.17  G-el chromatogram of
                      coagulated and adsorbed
                      raw sewage
       The TOG.constituents in the Zone 3 are mainly low molecular
       carbohydrates, amino acids, and low molecular fatty acids that
       are easily decomposed by biological actions.
       By the combinations of the above mentioned phenomena, as is seen
       in. Figure 4.15, almost no organic substances are detected in the
       effluent which has passed through activated sludge, alum or lime
       coagulation with sedimentation and sand filtration, and the activated
       carbon adsorption process arranged in series.
       Inorganic impurities in the Zone 4 are effectively removed by the
       processes of electrodialysis, ion exchange and so on.  For the
       portion,  electric conductivity is available to use as a compre-
       hensive water quality index.
4-3  Conclusion
     For the removal of organics from wastewater, three comprehensive
     water quality indices such as TOG, E260 m|i, and E220 imj, connected
     with impurity size distributions could describe the treatability of
     various types of treatment process such as biological process,
     chemical coagulation, carbon adsorption, and so on.
                                   187

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                              REFERENCES
l)  Tambo,N., Lecture note of water treatment engineering, Department
    of Sanitary Engineering, Hokkaido University, Sapporo, Japan (1968)
2)  Tambo,N., Kamei,T., and Tanaka,T.,  An investigation of advanced
    sewage treatment for the processes  of coagulation and carbon
    adsorption, Committee report on waste water reuse, Japan industrial
    water and wastewater association (1971)
3)  Tambo,N., Kamei,T., and Uasa,A.,  Behaviors of organic pollutants
    in the physico-chemical treatment processes,  Committee report on
    higher order water and wastewater controls,  Japan society of civil
    engineering, Sanitary engineering committee  (l97l)
4)  Standard method for the examination of water and wastewater, IJth
    edition, APHA,  AWA,  ¥PCF (l97l)
                                 188

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                                AGENDA

                        AMERICAN PRESENTATIONS
TUESDAY, FEBRUARY 12:

       THE FEDERAL WATER POLLUTION CONTROL ACT AMENDMENTS OF 1972
                           FEDERAL VIEWPOINTS

       THE FEDERAL WATER POLLUTION CONTROL ACT AMENDMENTS OF 1972
                            STATE VIEWPOINTS

       EPA OVERALL RESEARCH PROGRAM AND WASTEWATER TREATMENT RESEARCH
WEDNESDAY, FEBRUARY 13:

       TREATMENT AND DISPOSAL OF SLUDGE FROM MUNICIPAL WASTEWATER
                    PLANTS IN THE UNITED STATES

       EXPERIENCES WITH SLUDGE HANDLING IN TEXAS
THURSDAY, FEBRUARY 14:

       PHYSICAL-CHEMICAL NITROGEN REMOVAL WASTEWATER TREATMENT

       SLUDGES GENERATED IN PHOSPHATE REMOVAL PROCESSES

       EPA EXPERIENCES IN OXYGEN-ACTIVATED SLUDGE

       AERATION SYSTEMS FOR METRO CHICAGO

       OXYGEN ACTIVATED SLUDGE SYSTEMS IN TEXAS

       SUSPENDED SOLIDS REMOVAL PROCESSES STUDIED AT METRO CHICAGO

       METRO CHICAGO - STUDIES ON NITRIFICATION

       STORM AND COMBINED SEWER ABATEMENT TECHNOLOGY IN THE UNITED STATES
                              - AN OVERVIEW -
                                  189

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 THE FEDERAL WATER POLLUTION CONTROL ACT AMENDMENTS  OF  1972

                     FEDERAL VIEWPOINTS
                     CHARLES H. SUTFIN
           MUNICIPAL WASTE WATER SYSTEMS DIVISION
             OFFICE OF WATER PROGRAM OPERATIONS
            U.S. ENVIRONMENTAL PROTECTION AGENCY
                   WASHINGTON, D.C. 20460
                        PRESENTED AT

THIRD U.S./JAPAN CONFERENCE ON SEWAGE TREATMENT TECHNOLOGY
                        TOKYO, JAPAN
                        FEBRUARY 1974
                             190

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         THE  FEDERAL WATER POLLUTION CONTROL ACT AMENDMENTS OF 1972




                             FEDERAL VIEWPOINTS







                               INTRODUCTION





       In the United States, improving and maintaining the quality of our




waters requires a total national commitment at all levels.  For a long time




in the United States water pollution was considered to be a matter for only




local concern.  Since 1956, however, the Federal government and the States




have been actively assisting local communities with funds and technical




assistance.  Still this effort was not enough.  The pollution of the waters




grew to be a larger problem chiefly because of increased urbanization and




industrialization.




       Faced with this situation, our Congress developed the Federal Water




Pollution Control Act Amendments of 1972 to provide planning and actions to




deal with water pollution.  This legislation covers a wide range of activi-




ties.  However, the objectives and goals are expressed in the very first




paragraphs of the Act, to wit:




       1.  By 1985, elimination of discharges of pollutants into




           navigable waters.




       2.  By 1983, the attainment of water quality which provides




           for the protection and propagation of fish, shellfish, and




           wildlife, and recreation in and on the waters.




       3.  Prohibition of the discharge of toxic pollutants in toxic




           amounts.
                                   191

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       4.  Federal financial assistance for the construction of




           publicly owned waste treatment works.




       5.  Fostering of areawide waste treatment management




           planning processes.




       6.  Maintaining a major research and demonstration effort




           to develop technology necessary to eliminate the discharge




           of pollutants into the navigable waters, waters of the




           contiguous zone, and the ocean.




       At our last conference in December of 1972 we were just beginning




to implement the Act.  Since then we have worked very hard, learned much




and in doing so have made significant progress toward full implementation




of the Act.  Today, I would like to describe to you our efforts over the




past year.  Since my specific area of responsibility is in municipal




wastewater treatment technology, I will emphasize that subject area while




giving a broad overview of the other portions  of EPA's responsibility




under the Act.





                           EFFLUENT LIMITATIONS




       In general, the new legislation provides for definite effluent




limitations for discharges into receiving waters, rather than application




of the former provisions whereby water quality standards for the particular




waters governed.  Municipalities must have secondary treatment of their




wastewaters by July 1977 or 1978 under the law.  However, where waste-




waters given secondary treatment will not achieve the water quality




standards of the receiving body of water, higher than secondary treatment




must be provided.  This means, for example, that a State may set higher
                                   192

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standards than secondary treatment for a particular lake, river, or estuary.




These higher standards will determine the degree of treatment that must be




provided to wastewaters discharged to the waterway.





       On August 17, 1973 EPA published a final regulation which establish-




es the definition for the achievement of secondary treatment.  It requires,




in general, 85 per cent removal or 30 mg/1 of BOD and suspended solids,




whichever is more stringent.  All municipalities must provide treatment




of their wastewaters, at least to this standard, by July 1977 with some




extensions to 1978 in the case of plants that are under construction.





       The law also provides that no grant can be made with 1975 funds




(available January 1, 1974) unless the treatment process involves the




use of the best practicable technology currently available and further —




all municipalities, whether or not they receive grants, must have the best




practicable treatment by 1983.  We have drafted the best practicable tech-




nology regulation and it is now in the final stages of approval for publi-




cation as a proposal.  We have provided you with copies and welcome your




comments and suggestions.  Basically, the regulation establishes criteria




for three basic alternative waste management techniques which must be




considered and evaluated for cost-effectiveness.  The alternatives and




criteria are summarized as follows:
                                   193

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Treatment and Discharge
                                Monthly/Weekly
                                   Averages
BOD-                              30/45 mg/1

ss                                30/45 mg/1     (Equivalent to
                                                  Secondary Treatment)

Fecal Coliform                   200/400/100 ml

PH                                   (6-9)


For treatment works over 1.0 MGD or 10,000 pop. or not discharing

to the open ocean.


UOD                               50/75 mg/1  @ 20°C+

UBOD                              30/45 mg/1  @ 20°C -

UOD  = 1.5(BOD )   +  4.6(NH  as N)   -  1.0(D.O.)
              5            3
UBOD = 1.5(BOD    -  1.0(D.O.)


Land Application


Permanent Ground Water Criteria

   Chemical Parameters               EPA Drinking
                                     Water Supply
                                     Standards

   Pesticides/Organics               EPA Drinking
                                     Water Supply
                                     Standards

Point Source Discharge Criteria

   Same as Treatment and Discharge Levels


Reuse

Not to Exceed the Above Levels
                                194

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       In the case of industrial discharges, the effluent  limitations




to be imposed must be derived from effluent guidelines now being developed




for 28 basic industrial categories that contribute significantly to water




quality problems.  These guidelines for industry put into  definite terms




the 1972 law's goals, i.e. "best practicable technology" by 1977 and then




"best available technology" by 1983.







                                  PERMITS




       The Act establishes a new system of permits for discharges into




the Nation's waters,  replacing the 1899 refuse Act permit program.   No




discharge from any point source is allowed without a permit.   These must




be obtained for publicly owned treatment plants as well as industrial




dischargers.  Over 20,000 municipal treatment plants must obtain permits




by December 1974.   A typical permit will contain a schedule for upgrading




treatment to come within prescribed effluent limitations.





       Any discharge not in conformity with a permit will be  unlawful,




and, if willful and negligent, will be subject to a penalty of from




$2500 to $25,000 per day of violation.  On the part of EPA, court actions




will be used as a last resort.  We propose to give industries and munici-




palities the ample opportunity to comply with the requirements on a




voluntary basis.






                   PRETREATMENT STANDARDS AND GUIDELINES





       The pretreatment standards can be described in terms of the two




major objectives outlined by Congress.
                                  195

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       The first objective, to prevent the introduction of pollutants




which would pass through inadequately treated, requires that the term




"inadequately treated" be defined.  The regulations are based on the




premise that incompatible pollutants introduced by an industry are




inadequately treated if they pass through publicly owned treatment works




in amounts greater than would be permitted if the user discharged directly




to the receiving waters.  Accordingly, the pretreatment standards for in-




compatible pollutants are the same as the requirements for direct discharge.




These requirements are to be based upon application of the best practicable




control technology currently available.




       An incompatible pollutant is defined as any pollutant other than




BOD, suspended solids, pH and fecal coliform bacteria plus those pollutants




that the municipal plant was specifically designed to treat.  A less strin-




gent pretreatment standard is permitted for thos incompatible pollutants




which the municipality is committed to remove in its permit for the publicly




owned treatment works.




       The standards for incompatible pollutants apply only to major indus-




tries so as to reduce the number of industries which would have to pretreat




and yet cover those industries that could have a significant impact upon




the municipal plant.




       The second objective which the standards must address is to protect




the operation of the publicly owned treatment works.  Under this objective,




four prohibited discharges are listed in the standards.




       There will be situations when the Federal pretreatment standards




will not be sufficient to protect the operation of the publicly owned




treatment works or prevent the discharge of industrial pollutants inade-
                                   196

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quately treated.  In such cases, the municipality would have to supplement




the Federal Standards.  The pretreatment guidelines are intended to assist




municipalities in accomplishing this.






                      CONSTRUCTION GRANT REGULATIONS





       To enable municipalities to meet effluent limitations and permit




requirements, the new amendments authorize Federal grants to municipalities




for assistance in building sewage treatment facilities.  These grants are




mandated at the rate of 75 percent of eligible costs of approved projects.




       To facilitate the processing of these grants, EPA has issued the




"Title II Regulations."  These regulations set forth policies and procedures




concerning the processing of applications for grant assistance.  Included




is the provision that all projects must meet planning requirements and




receive a priority certification from the State.




       The regulations have been written with a view toward giving communi-




ties and States as much autonomy in making decisions as is possible under




law.  For example, the responsibility for review of plans and specifications




for projects is to be passed to States as rapidly as States become able.




       An innovation in the regulations is the introduction of a three-




step grant process.  Step !_ allows a separate grant for the preparation




of preliminary studies and engineering.  Step 2 provides for a grant for




the preparation of construction drawings and specifications, and Step 3




is for a grant for the building and erection of the treatment works.




This division of the financing of a grant for a project will accelerate




payments to the communities and allow available funds to be spread over




a larger number of projects.  We believe that this procedure will be of
                                    197

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great assistance to communities.  It has already allowed a larger number




of projects to go forward in most areas than would have been the case




under the former regulations and law.




       Final "Title II Regulations" will be published soon.




       I would like to briefly mention some other requirements under




the Act that you will be interested in:






                                PLANNING




       The law lays down firm requirements for the planning of pollution




abatement programs, and for control programs tied directly to the plans.




For example, each State must have a continuing planning process which will




result in water quality control plans for all navigable waters within the




State.  Included in such plans must be an inventory and ranking, in order




of priority, of needs for construction of wastewater treatment plants re-




quired to meet the applicable standards.   In addition, each sewage treatment




works must have a facility plan which will consider not only the technical




but also the social and economic aspects of a project.  Involved here are




environmental impact statements prepared by EPA when major controversies




are unresolved.





                          INFILTRATION/INFLOW




       Section 201 of the Act states that the EPA Administrator shall not




approve a grant after July 1, 1973 unless the applicant shows that each




sewer system discharging into the treatment works is not subject to excessive




infiltration.  The construction grant regulations require that an analysis




be made of the sewer system involved to determine if there are indications




of excessive infiltration.  If so, an infiltration study has to be made to




determine action to handle the infiltration problem economically.  Such
                                   198

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studies are eligible grant costs, usually as part of the Step 2 grant




process.  There will be cases, where it will be more economic, on a cost-




effective basis to treat infiltration by building a larger plant, rather




than trying to seal a sewer system.  Also, it is recognized that in many




cases it may not be feasible to remedy infiltration/inflow immediately.




A reasonable and satisfactory abatement schedule may be agreed upon while




the project goes forward.




       An infiltration/inflow analysis has always been part of a well-




planned project.  Therefore, we do not look upon this requirement as being




burdensome in the design of sewage treatment systems.  Guidelines on infil-




tration/inflow analysis will be published shortly at about the same time




as final construction grant regulations.






                            COST-EFFECTIVENESS




       Section 212 of the Act also specifies that the Administrator shall




publish guidelines on methods of cost-effectiveness analysis for the con-




struction of treatment works.  These guidelines were published in final




form on September 10, 1973.  Basically, the guidelines contain uniform




economic analysis procedures which must be incorporated into all grant




applications.  This will assure adequate data and analysis demonstrating




the project to be the most cost-effective over the design life of the




works.  The analysis must include consideration of both capital and oper-




ation and maintenance costs.




       Again, cost effectiveness analysis has normally been undertaken




as part of any sound engineering analysis, even though it may not have




been labeled as such.  The law formalizes the procedures.  The requirement
                                   199

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is not expected to cause any great problems since the process is familiar




to those in the profession.





                 USER CHARGES AND INDUSTRIAL COST RECOVERY





       Having provided for Federal assistance in building wastewater




treatment facilities, the Act seeks to assure that the facilities will




be properly maintained and operated.  To accomplish this, communities




that are assisted with grants are required to have a user charge system




that insures that all users will pay their proportionate share of operation




and maintenance costs.  In addition, the law provides that industry, discharg-




ing into the system, must pay back its proportionate share of the Federal




grant.  Fifty percent of this payback may be used for liquidating the




community's cost of the project and for future expansion and reconstruction




of the project.  The remaining 50 percent reverts to the U.S. Treasury.




Final user charge and cost recovery regulations were published on August 21,




1973.





                      FINANCIAL NEEDS OF THE PROGRAM




       To achieve the goals of the program will be a costly venture.




Recent estimates indicate that it will require industry to expend for




capital improvements $12.9 billion to bring about the use of best practicable




technology by 1977 and an additional $7.8 billion to apply best economically




available technology by 1983.




       The needs of municipalities for financing has been the subject of




a recent survey.  The objective of the survey was to ascertain the funds




that would be required to meet the 1977 goals of attaining secondary




treatment or higher where water quality standards are higher.  The total




amount came to a total of over $60 billion.  $16.6 billion is required to
                                    200

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improve treatment plants to achieve secondary treatment, with an




additional $5.6 billion for further removing specific pollutants such




as phosphorus, nitrogen and organics to the extent required by legally




binding Federal, State, international and local actions.  $700 million is




required for eliminating infiltration/inflow conditions, $13.6 billion is




necessary for building new interceptors, force mains, and pumping stations,




$11 billion is estimated for new collection systems, and $12.7 billion is




required for the reduction of combined sewer overflows.  We know that some




of these figures are not absolutely accurate because of an inadequate data




base that we are even now engaged in strengthening.  We believe, however,




that the combined total of $36 billion for treatment plants, removal of




other pollutants, and the building of new interceptors is reasonably accurate.




The remaining $24 billion is probably too low a figure.





                       FEDERAL FINANCIAL ASSISTANCE




       The Federal government between 1956 and 1972 expended over $5 billion




to assist municipalities in building waste treatment facilities.  At present




another $9 billion is available for grants at 75 percent of construction




costs.  Four billion of this total was just added on January 1, 1974.




Further financing for after that date is now under study and review.






                                CONCLUSION




       The magnitude of the United States' program which I have just




described leads to my concluding remarks.  To make such a program viable




will require the utmost use of new technology and innovations.  Even samll




advances in improving the efficiency and effectiveness of sewage treatment




systems will result in major savings overall; significant advances will
                                   201

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reduce the load on our taxpayers who must pay for the improvements in




water quality.





       Your efforts in Japan to improve and maintain water quality must




present the same strains on your economic and social systems.  By joining




together to bring about the most efficient and effective application of




technology and ideas to the treatment of wastewaters, we can achieve more




than each of us can alone.   Our visit to Japan so far has been most bene-




ficial in this respect.  I  look forward to a successful conclusion of this




Conference.
                                  202

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THE FEDERAL WATER POLLUTION CONTROL ACT AMENDMENTS  OF  1972

                     STATE VIEWPOINT
          DICK WHITTINGTON, P.E., DEPUTY DIRECTOR
                 TEXAS WATER QUALITY BOARD
                      AUSTIN, TEXAS
                       PRESENTED AT
 THIRD U.S./JAPAN CONFERENCE ON SEWAGE TREATMENT TECHNOLOGY
                       TOKYO, JAPAN

                       FEBRUARY  1974
                             203

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                   FEDERAL WATER POLLUTION CONTROL ACT
                   AMENDMENTS OF 1972—STATE VIEWPOINT
       I believe it appropriate in the beginning to provide a limited
overview of the American system of state-federal relations inasmuch as
this will help you understand my view and the interactions of federal,
state, and local governments in the United States.
       The U.S. Constitution, written by representatives from the several
states, provides for a division of governmental powers between the federal
and state governments.  The division was accomplished by delegating to the
federal government specified powers plus the powers inherently required to
execute the delegated powers—all undelegated powers to remain with the
states.

       Under this division of powers, the control of water pollution was
for many years considered to be primarily a function of state government.
The federal government was considered as having the prime function when
its ability to discharge its delegated powers were endangered.  Along
these lines, the federal government in 1899 enacted a refuse act which
placed it into the water pollution effort in a very limited way—only
to protect navigation channels from excessive siltation or clogging.
The 1899 Refuse Act required a federal permit to discharge refuse-laden
wastewaters into navigable waters.  Several years ago, as a result of a
judicial decision, the 1899 Refuse Act was expanded in scope, wrongly
in the opinion of many, to consider all pollutants—not only suspended
solids.  The 1972 Amendments,  at least to some degree, is an outgrowth
                                   204

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of the 1899 Refuse Act since it sets up a comprehensive federal waste




discharge permit system.





       The U.S. Constitution has generally been interpreted so as to




provide federal supremacy over state government when there is a conflict




involving the national interest.  This is the case with the 1972 Amendments




where it was decided that the national interest was being endangered because




of the failure of the several states as a whole to adequately control water




pollution.  When this is done, a state's power to cope with its own problems




as it sees fit is to a considerable degree set aside—even though a particular




state may be doing its job satisfactorily.





       Under the division of powers previously discussed, the State of




Texas proceeded many years ago to inaugurate programs to control water




pollution—other states also inaugurated programs, some very good, some




very bad.  I think Texas has a good program.  We have required secondary




treatment of domestic sewage for some 30 years.  We have had a permit




program covering both municipal and industrial discharges, including




agriculture, since 1962.  We have had a mandatory self-monitoring program




in operation since 1970.  All of these programs and more are now incorpor-




ated into the 1972 Amendments and made federal programs.  This fact,




coupled with detailed regulations promulgated under the Act requires




that all our programs be revamped and restructured to fit the pattern




mandated by the federal government.  This necessarily involves a great




deal of lost motion and unnecessary expense.  In this case, states who




did not have comprehensive programs as of the passage of the Act are




probably in an advantageous position since they will be able to structure




programs from the beginning to fit the federal mold.  As each of you know,
                                    205

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it is easier to construct a new house to detailed  specifications than it




is to rebuild an old one—even though the old structure may be  sound and




sturdy.  We are in that position in Texas and we are  trying to  rebuild our




house since we recognize the Act as the law of the  land.





       I think it would be appropriate at this time to say  that the  various




state governments have no single viewpoint on the merits of the 1972 Act.




This same divergence of opinion exists even within  individual states between




state civil servants, the political leadership, and the people.   In  general,




I think it would be true that: (1) the state civil  servants, almost  to a man,




think the law has serious flaws and has been wrongly  implemented;  (2)  the




political leadership recognizes the law as a political necessity;  and (3) the




people have no specific view—they are merely dissatisfied  with the  progress




the states have made in correcting pollution problems.  In  these  regards, I




shall only attempt to discuss the Texas viewpoint,  generally as seen by state




pollution control officials.





       Within the time allotted to me, let us look  at some  aspects of the




law or regulations promulgated therunder which we consider  problems.





       Section 101(b) states that it is the intent  of Congress  that  the




rights of the states to protect and use its waters  be preserved.   In




actuality, the federal role is all pervasive and conformity to  the federal




mold is much more mandatory than statutory language would require.   This,




we think, is a mistake since it fails to take into  account  regional  differ-




ences between the states in law,  custom, history, land use, topography, etc.




The insistence on uniformity has caused considerable wear and tear on nerves




and tempers, and has served no good purpose.
                                   206

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       Section 101(a) sets forth the goals of the Act—recreational use




water quality in all streams by 1983 and no discharge of pollutants by




1985.  I think these goals are unrealistic, particularly the schedules.




Such environmental daydreaming will never take the. place of common sense




and sound technical judgment.





       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.  Federal waste discharge permits as




provided for in Section. 402 of the Act will be used to implement these




requirements including the schedules.  So far, all is well and proper,




except possibly the schedule.





       When, however, 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 results.






       Section 202(a) provides that the federal shore of the costs of




publicly owned treatment works shall be 75%.  A survey conducted under




Section 516(b) (2) of the Act to determine the needs of all the states




resulted in a need for Texas in excess of 800 million dollars, and we




think at the state level this is too low.  The actual level of funding




as evidenced by past actions will fall far short of the need.  Thus,




taking into consideration both the permit program and the grant program,




it would appear to us that the federal government is telling state and




local government on the one hand through the permit system to construct




rapidly the needed works; and on the other hand telling these same
                                    207

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governments through the grant program that they are  entitled  to 75%




federal funding, but that it will not be forthcoming in many  cases  in




time to meet the 1977 deadline.  This in our judgment is confusing. We




are very hopeful that the Congress will resolve this  problem  so that  our




nation can proceed harmoniously to construct the necessary works to finish




the task of cleaning up our waters.





       Title IV of the Act provides for a permit program to control waste-




water discharges, and provides that the federal government can  delegate




under certain conditions the responsibility for the administration  of this




program to the states.  EPA has promulgated restrictive regulations concern-




ing the prerequisite to receive delegation and has interpreted  the  regulations




narrowly.  They appear to be attempting to find reasons why a state should




not be given delegation, rather than how to overcome  obstacles  to delegation.




We think this is a mistake and that this fails to properly utilize existing




trained manpower available in state organizations.  In order to partially




overcome this problem, our state and the EPA Region in which we are located




have worked out an informal arrangement to make our resources available.





       Many other issues could be raised; however, suffice it to say that we




think that inadequate attention has been given in the law and its implementa-




tion toward effectively utilizing existing state organizations.  This is,




we believe, primarily due to an attempt to fit all state programs—good and




bad—into one rigid mold.





       Contrary to what you may think at this point  in my presentation,




I do not think all aspects of the Act are bad.  The concept of  setting




water quality standards for the nation's waters is sound and necessary.
                                    208

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The concept of specifying minimum treatment levels regardless of stream




requirements is sound—we have followed this concept in Texas in the case




of municipal sewage for over 30 years.  The continuing planning process




mandated by Section 303 (e)  of the Act is a sound concept.  It has enabled




us to take a more effective look at the overall water quality needs in each




river basin and will result in a much more coordinated control program than




has heretofore been the case.  The self-monitoring program wherein each




waste discharger is required to monitor the quantity of pollutants he dis-




charges to public waters and report this information to the government is




sound.  We have had such a program in operation in Texas since 1970 and it




has been one of the most effective tools we have found in recent years in




abating pollution.  There are many other aspects of the Act which are




worthwhile and necessary.





       In summary, let me say that while I have obvious concerns about the




Act itself and the manner in which EPA has implemented the Act, it is a far-




reaching Act clearly setting forth our government and our people's determi-




nation to solve our nation's water pollution problems.  I am personally




very confident that in a short time the rough spots will be smoothed over,




and we will complete the job of cleaning our nation's waters, started so




many years ago.  I started in this business over 20 years ago, and I am




glad to see the climate of public opinion change to support the clean-up




effort.  Without the public's support, the job will not be done.  The




passage of the 1972 Act is very significant in that it clearly signals




our nation's commitment to clean water.
                                    209

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           EPA OVERALL  RESEARCH  PROGRAM
        AND WASTEWATER  TREATMENT RESEARCH
                  F. M. MIDDLETON
                  DEPUTY  DIRECTOR
        NATIONAL  ENVIRONMENTAL  RESEARCH CENTER
           ENVIRONMENTAL PROTECTION AGENCY
                 CINCINNATI, OHIO
                     PRESENTED AT

THIRD U.S./JAPAN CONFERENCE ON SEWAGE TREATMENT TECHNOLOGY
                     TOKYO, JAPAN
                     FEBRUARY 1974
                           210

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                       EPA OVERALL RESEARCH PROGRAM
                    AND WASTEWATER TREATMENT RESEARCH

                               ORGANIZATION

       The Environmental Protection Agency is headed by an Administrator,
now Mr. Russell E.  Train.  To carry out the EPA programs there are Assistant
Administrators for various programs as shown in Chart I.

       Research is directed by the Assistant Administrator for Research and
Development, Dr. Stanley M. Greenfield.  His office is in Washington, D.C.
The Office of Research and Development has about 1800 employees and a budget
of about $120,000,000 per year.  Chart II shows how the Office is organized.

       To conduct the research for EPA, four National Environmental Research
Centers have been established.  These NERC's are located at Cincinnati, Ohio;
Corvallis, Oregon;  Research Triangle Park, North Carolina and Las Vegas,
Nevada.  There are about ten smaller laboratories in other locations that
are administered by the NERC's.  The brochures you have been provided explain
the programs of the NERC's further.  Chart III shows the organization of the
Cincinnati NERC - The Robert A. Taft Laboratory.

                        HOW OUR RESEARCH IS CONDUCTED

       Wastewater treatment research is conducted by the Advanced Waste
Treatment Research Laboratory in Cincinnati.  Industrial waste treatment
research is conducted at Edison, New Jersey and at some other NERC's.  Our
Storm and Combined Sewer Research Program is also located at Edison, New
Jersey.
                                   211

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       About 150 people work in the programs devoted to domestic and




industrial waste treatment.  The budget for domestic wastewater is about




$10,000,000 and the industrial waste budget is about the same.





       The objectives of our treatment research programs are to improve




old methods and devise new methods for the management and control of waste-




waters to enhance the quality of the Nation's water and meet the quality




standards required.





       How do we decide upon research projects?  First of all, the EPA is




guided by certain laws that have been enacted.  Much of our work in water




pollution is directed by the Federal Water Pollution Amendments Act of 1972 -




Public Law 92-500.  Within the policies of the EPA, the Office of Research




and Development develops a basic strategy to meet the Agency needs.  Research




needs are solicited from EPA Headquarters and field programs.  Using these




needs and the strategy documents, our Washington Headquarters, with help




from the laboratories, draws up a general research plan and designates the




amount of money to be spent in each area of work.  It is then the job of




the research staff to design detailed work plans.  After the work plans




are approved, the project gets underway.  We project our research for five




to seven years.  We perform research in our own laboratories but we also




make extensive use of cities,  industries, commercial research groups and




universities to conduct research for us.  Chart IV shws our planning




process in graphical form.  Chart V is a list of major topics we are




conducting research on in the municipal and industrial waste field.




Chart VI shwos a summary sheet on one project and a graphical network




diagram of the project.
                                     212

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                            TECHNOLOGY TRANSFER






       Once the research is completed, it is made available to the Agency




programs that has requested it and to others.  There are now several hundred




reports on the research that has been done.  These reports are available to




you.





       To expedite the use of new technology, EPA has special teams of




researchers and outside consultants put on special two- or three-day seminars




all over the country for consulting engineers, state authorities, city




governments and the like.  We also produce manuals on various subjects




and distribute them widely.  You are already familiar with our Advanced




Waste Treatment Manuals.
                                    213

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                                                                                                                          CHART   I
                                                                                                                   U. S. tNVlRONMENTAL PROTECTION AGENCY
                                                                                          OFFICE OF CIVIL UGHIS
                                                                                           AND UCBAN AFFAIRS
                                                                                          CAROL fHOMAJ 7S5-Oi«
                                                                                        OFFICE OF FEDERAL ACTIVITIES
                                                                                             SHUDCN MEYERS
                                                                                                 755-0777
ADMINIS1RAIC*
 RUSSfLL TWIN
   755-7700
                                                                                                                            DEPUTY ADMINISTRATOR
                                                                                                                             JOHN OUARLES, JR.
                                                                                                                                  755-77 IT
ro
^                                                                                                                                                          OFF ICC Of INIEaNATlONAL ACHVITKS
                                                                                                                                                                  FHZHUGH GRECN
                                                                                                                                                                     755-27 M
                                OFFICE OF PUBLIC AFFAIRS
                                     ANN DOR(
                                      755-0700
AiST. ADMINISIRATOS
FOR A H AND
WAIE8 PROOtAMS
ROBERT SANSOM
7i5-?6*0







	



OFFICE OF
All QUALITY
PLANNING AND
STANDARDS
1. J. STEIGtCV/ALD
(9)9) (.33-8576

OFFICE OF
MOBILE SOURCE
AIR POLLUTION
CONTROL
ERIC STORK
426-3464

OFFICE Of
WATtft PLANNING
AND STANDARDS
LILLIAN RCGELSON
7SS-Qt02

OFFICE OF
WATER PSOGRAM
OFLRAT1ONS
itctON i . sc;rcN
JOHN MeGLtNNON
(417) 223-7210

«GlO^; il - Nf.v VO«K
GERALD KAN SI El
(212) 2M-K23

•ECtOM III ' fHfLADELPHIA
D. SNYOEB III
(3151 597-9801

UGION TV - ATLANTA
JACK RAVAN
(404) 5Ji-5777

MGION V -CHICAGO
flANClSMAYO
(317) 313-5*50

REGION VI - DALLAS
ARIHUfl BUSCH
(JU) 7-49-1962

•EGION VII- KANSAS CUV
JE8OME SVOfte
(8)4) 374-5493

REGION VIII - OENVtl
JOHN CRHN
(3331 837-3B»

UClON IX - SAN MANOSCO
PAUL OaFALCO, Jt.
{415) 5U-232D

-------
                                                                     CHART  II

                                                            OFFICE OF RESEARCH AND DEVELOPMENT
                                                                    ASSISTANT ADMINISTRATOR
                                                                             FOR
                                                                   RESEARCH AND DEVELOPMENT

                                                                      STANLEY GREENFIELD
                                                                           755-2600
DEPUTY ASSISTANT ADMINISTRATOR
              FOR
     PROGRAM INTEGRATION
        LELAND ATTAWAY
           755-2611
DEPUTY ASSISTANT ADMINISTRATOR
             FOR
 ENVIRONMENTAL ENGINEERING
       A. C. TRAKOWSKI
           755-2532
                           MUNICIPAL POLLUTION
                            CONTROL DIVISION
                             WM. ROSENKRANZ
                                  522-0363
                                                          TECHNOLOGY
                                                          TRANSFER STAFF
                                                          ROBERT CROWE
                                                             755-0851
            INDUSTRIAL POLLUTION
              CONTROL DIVISION
                 WM. LACEY
                  522-0363
                          NON-POINT POLLUTION
                            CONTROL DIVISION
                             THOMAS MURPHY
                                 755-0628
               AIR POLLUTION
             CONTROL DIVISION
            RICHARD HARRINGTON
                  755-0628
                                                                     OFFICE CF PRINCIPAL
                                                                      SCIENCE ADVISER
                                                                           (VACANT)

                                                                   SCIENCE ADVISORY BOARD
                                                                                     OFFICE OF PROGRAM MANAGEMENT

                                                                                             DAVID STEPHEN
                                                                                                755-0475
   DEPUTY ASSISTANT ADMINISTRATOR
                 FOR
       ENVIRONMENTAL SCIENCES
            HERBERT WISER
               755-0655
                                                                                                                                      _L
                       DEPUTY ASSISTANT ADMINISTRATOR
                                     FOR
                            MONITORING SYSTEMS
                                WILLIS FOSTER
                                   755-2606
                                                           SPECIAL ASSISTANT
                                                           FOR WATER SUPPLY
                                                               RESEARCH
                                                          H. GORCHEV 755-2582
  HEALTH EFFECTS
     DIVISION
J. WESLEY CLAYTON
     755-0614
ECOLOGICAL PROCESSES
AND EFFECTS DIVISION
      (VACANT)
                                                             PLANNING AND
                                                              REVIEW STAFF
                                                               WM. SAVERS
                                                                755-2553
   EQUIPMENT AND
TECHNIQUES DIVISION
    HENRY ENOS
      755-0448
    WASHINGTON ENVIRONMENTAL
           RESEARCH CENTER
             LARRY RUFF
              755-0477
              QUALITY ASSURANCE
                   DIVISION
               GUNTIS OZOLINS  .
                   755-0434
  DATA & INFORA.1ATION
   RESEARCH DIVISION
     MATTHEW BILLS
        755-0468
                                                        NATIONAL ENVIRONMENTAL RESEARCH CENTERS
                                                     CINCINNATI                     LAS VEGAS
                                                     CORVALLIS                      RESEARCH TRIANGLE PARK
                                                                   ASSOCIATED LABORATORIES

-------
rv>
                                              CHART  III

                         ORGANIZATION FOR NATIONAL ENVIRONMENTAL  RESEARCH CENTER
                                   THE ENVIRONMENTAL PROTECTION AGENCY
                                           CINCINNATI,-OHIO






PROGRAM









STAFF

i i
ADVANCED
WASTE TREATMENT
RESEARCH
LABORATORY
BRANCHES:
Treatment Process
Development

Systems and
Engineering
Evaluation

Technology
Development
Support























INDUSTRIAL
WASTE TREATMENT
RESEARCH
LABORATORY
BRANCHES:
Oil Spill Technology

Hazardous Spill
Technology

Industrial Pollution
Control

Watercraft and
Recreational
Pollution Control

Mining Pollution
Control







'


















DIRECTOR
DEPUTY









I

SOLID AND HAZARDOUS
WASTE
RES
^RCU

LABORATORY
BRANCHES:
Disposal







Processing




















































DIRE'TOR








































I



PUBLIC









AFFAIRS STAFF














1 .
WATER SUPPLY
RESEARCH



LABORATORY
BRANCHES:
Criteria Development



Standards Attainment




















































METHODS DEVELOPMENT
AND QUALITY ASSURANCE
RESEARCH
LABORATORY
BRANCHES:
Physical-Chemical
Methods

Biological Methods

Quality Assurance and
Laboratory Evaluation

Instrumentation
Development

Radiochemlstry and
Nuclear Engineering

1






































ENVIRONMENTAL
TOXICOLOGY
RESEARCH
LABORATORY
BRANCHES:
Experimental Toxicology

Exposure Systems
and Assessment

Biological Effects








                                                                                  September 74. 1973

-------
                      CHART IV
OFFICE OF RESEARCH AND DEVELOPMENT PLANNING PROJECTS
      EPA POLICIES AND
      LEGAL RESPONSIBILITIES
           OFFICE OF RESEARCH AND DEVELOPMENT
           RESEARCH NEEDS RECEIVED FROM OTHER
           EPA PROGRAMS, STATES, ETC.
                STRATEGY PLAN
                CONCURRED IN BY OTHER EPA PROGRAMS
                GENERAL PROJECT PLANS
                MONEY ESTIMATES PREPARED
                LABORATORY RESEARCH PERSONNEL
           DESIGN DETAILED STUDIES
                APPROVAL OF PLANS
                  WORK BEGINS
                         217

-------
                                         CHART ¥


           RESEARCH  PROJECTS IN DOMESTIC AND INDUSTRIAL WASTE TREATMENT AND CONTROL

                                     NERC-CINCINNATI

                                          1974

Advanced Waste Treatment Research Laboratory

                	Title	

                Demonstrate Combinations of Processes  to Meet Water
                  Quality Needs

                Methods & Processes to Provide Improved Operation &
                  Maintanence,  In-System treatment, & Treatment of Joint
                  Municipal &  Industrial Wastes

                Research & Investigation of Joint Liquid-Solid Waste
                  Collection &  Treatment

                Treatment of Combined Sewer Overflows & Storm Water Discharges

                Technology for  Hydraulic & Pollutant Control of Urban Runoff

                Simulation Models for Total Management of Sewerage Systems

                Methods, Processes, & Systems  to Reduce Water Use & Total
                  Sewage Flow

                Research, Development,  & Pilot Projects to Eliminate
                Pollution from  Sewage in Rural or Other Areas Generating
                Small Flows

                Wastewater Renovation and Reuse

                Wastewater System Instrumentation & Automation

                Wastewater Sludge Processing & Treatment

                Wastewater Treatment Sludge Disposal

                Control of Nutrients in Wastewater

                Suspended & Colloidal Solids Removal from Municipal Wastewater

                Biological Treatment Process Improvements for Municipal
                Wastewater Applications

                Municipal Wastewater Disinfection Process Development and
                  Demonstration

                Reduction of Total Dissolved Solids (TDS) & Heavy Metals
                  in Municipal Wastewaters

                Control of Dissolved Organics  in Municipal Wastewater b\
                  Physical-Chemical Processes
                                      218

-------
                                       CHART V (continued)
Industriaj^_Waste Troatinent Research Laboratory
                Technology Research for the Elimination of the Discharge of
                  Pollutants from the Inorganic & Miscellaneous Chemicals
                  Industries

                Technology Research for the Elimination of the Discharge of
                  Pollutants from the Non-Ferrous Metals & Electroplating
                  Industries

                Technology Research for the Elimination of the Discharge of
                  Pollutants from the Rubber & Plastics Industries

                Completion of FY-73 Work Plan ROAPs 21 APK, 21 APL and
                  21 APO

                Treatment of Mine Drainage

                Pollution Control Methods for Surface Mining

                Control of Pollution from Underground Mining of Solid Fuels

                New Mining Methods

                Mine Water Pollution Control Demonstrations - Section 107

                OHMSETT Support

                Chemical Identification of Oil Spills

                Oil Spill Containment Devices

                Equipment for Physically Removing Oil Spilled in the
                  Environment

                 Waste Oil Recycling

                 Prevention of Hazardous Material Spills

                 Hazardous Material Spill Emergency Response

                 Hazardous Material Spill Control and Removal

                 Separation & Recovery  of Removed Spilled Hazardous Materials

                 Environmental Evaluation of  Devices & Techniques  to Control
                  Hazardous  Material Spills
                                   219

-------
                                Off ice-of Ccscarcli iiml MonUon'ny
                        RESEARCH  Ci'.JfiCTIVi:  ACilJCVIII-SilT PLAM SUMMARY
.f-0-OiK.VI tur_M

 Treatment Process Development
   and Optimization
                                        Municipal Technology
                                                                                      i.o.
                                                                                21-AST
                                                                                .'i'-.-^i Lir::.'i: :.3.
                                                                                 1B2043
EI:OS/i...V HUE:
             Reduction of  Total Dissolved Solids (TDS)  and
              Heavy Metals in Municipal Wastewaters
                                                                              21ABO
                                                                              21AAP
                                                                                        21AAQ
                                                                                        21AAS
 Design guidelines for.  cost-optimized reverse  osmosis, ion exchange and distillation
 processes based on large-scale demonstrations.   Reports on capabilities of vaste
 treatment processes  to remove heavy metals and  possible process  modifications  to
 enhance removal of metals  and toxic non-metals,
                                                                                     c;)
Fcr,.i.
         JLL9JL
         .AQ.i
                      356
                      1.2
                            FY. 74
                             68
                             2.3
    Sponsor
Region V
              HEEO SPfiSORS
                   Priority
     Cinti
                 131/171
                  17/62
                  191/454
                               05AC(
                                       FY  75
                                         220
                                         2:3
                                                  Clannod
                                                  196!
                                                FY  76
375
2.3
                                                             ActuU
                                                            1F6T"
                                                           FY77
600
                                                                        CRG^'iiJATiC1; r.iS?:::siri.-L FG?.
                                                                        FFC£PA?.;NJ A;;3 i.".?L£:'.c.'iT::;3 ".CA
                                                                     L/3/oiv
                                                                     (fivs di
                                                                                   67024
                                                                        Sf:0 KLATIQ
                                                                    Supporting FJ !:o'
                   FT 78
                                                                      510
                                                                      2.3
                                               Pr.C;P.AM AREA PK10.71TY
                                        A;slr;icd Ty     Priority
                               16 -VKJJJ[
                              24 AXl'i!
                  FY 79
                                                                              663
                  O.i

-------
                                           17
	a i AST
LEDUCTIOS OF TOTAL DISSOLVED SOLIDS  (TDS) ANDJ
   HEAVY HKTALS IN MUlilCIl'^L S'ASTEWATERS
ADVANCED BASTE TREATMENT RESEARCH LAOORATOHYj
	HERC-C1MTVVAT1	
                                                        OF REMOVING  ADDITIONAL TOXIC
                                                        METALS &  NON-METALS IN P-C
                                                        PILOT PLANT
                                                        Inhouse
                                                        Begin; 1973/2nd  End:  1974/2nd Qti
                                                                                      .LUATIO.V OF" PROCESS   $110,000
                                                                                   [MODIFICATION'S TO ENHANCE'
                                                                                   BEMOVAL5 OF SPECIFIC METALS
                                                                                   AND INORGANIC NON-METALS
                                                                                   Jnhouse
                                                                                      in- 1974/3rd End: 1976/2|id  Qtr
/-T7>\ l8
( DecisionX
Data To 1
iDemonstrate/
\ 1977/1 /
SHORT EVXLUATIO^S OF
'-ETAL-Rf-'OVAL PRCCKS
TREATKEST PLANTS
lie-jin: j376/3rd End:
$152,500
ES AT

1978/2nd Qtr
23


I'REPARE MANUAL OF
PRACTICE FOR METALS
Becin: 197S/3rd End

S 7SjOOO
REyOVAL
1979/Znd


Qtr

           B.REVERSE OSMOSIS.
           01. 05, 07,  10, 11
                            [LABORATORY A.VD PILOT STUDIES!]
                            | OF REVERSE OSMOSIS         |
DEMONSTRATE CURRENT RO 5311,000
TECHNOLOGY AT 150,000 GPD

17


RO DEMONSTRATION' 5195,000
USIN-G CHEMICALLY TREATED RAW
ffASTEWATES KITH OR WITHOUT
ACTIVATED CARBON
Begin: 1975/3rd End: 1976/?nd Qtr



/
\

                                                                                                                  00,000
                                                                                         ASSEMBLIES OH CONFIGURATIONS
                                                                                         Inhouse
                                                                                         [Begin: 1976/3rd End: 1977/?nd Qt
no

                                                                                                                       DEMONSTRATE NEWT RO
                                                                                                                       MEMBIUXE ASSEMBLY OR
                                                                                                                       COSTIC'JRATION
                                                                                                                       Demonstration Grant
                                                                                                                                                                                                                             fpREPARE MANUAL OK5100,000
                                                                                                                                                                                                                              PRACTICE FOH REVERSE  OSMOSIS
                                                                                                                                                                                                                                     137973rd End:  X9
                                                                                                                                                                                                                          E.ECOHOM1C ftKALYSIg
          C.ION EXCHANGE
           03, o«, 06 [PILOT_ STUDIES" OT" ION EXCR.VMCE fr
                                                 OKSTRATE FIXED BED  S2SO,000
                                               ION-EXCHANGE AT 100,000 GPD
                                               Demonstration Grant
                                               Begin:  1974/3rd End:  1976/2KJ Pt
                                                                                                                                            [DEVELOP PROCESS FOR  S15~57ot
                                                                                                                                            '''.ECCVESV OF SH_ FROM ION'
                                                                                                                                            -:.XCHASGZ REGEStRANT AND
                                                                                                                                            DISPOSAL OF RESIDUAL BRINE
                                                                                                                                            fetepi:
                                                                                                                                                   1976/3rd End: 1978/lnd
                                                                                                                                                                                                                                               ; TO
                                                                                                                                                                                                                                                      5100,000
                                                                                                                                                                                                                                                       :  OF
                                                                                                                                                                                                                                 LICATION FOR EACH
                                                                                                                                                                                                                              DEMINERALIZATION PROCESS
                                                                                                                                                                                                                              'Contract
                                                                                                                                                                                                                              Begin:  1979/3rd End: 198Q/2nd  Qtr
   PARE  MANUAL OK    3100,000
.PRACTICE FOB ION £XCHASOE
IContract
[Begin: 1976/3rd End:  I979/2nd Qtr

                                                                                                                                            IREGENERAFION 'OF NOVEL
                                                                                                                                            ,ION EXCHANGE MATERIAL
                                                                                                                                            (Contract

PREPARE 1IANUA
PRACTICE FOR
Contract
BcK'n: 1980^3

1, Oh' S IOO ,l>00
DISTILLATION
r
-------
      TREATMENT  AND  DISPOSAL OF SLUDGE FROM MUNICIPAL
          WASTEWATER PLANTS IN THE UNITED STATES
               DR. JOSEPH B. FARRELL, CHIEF
                 ULTIMATE DISPOSAL SECTION
           TREATMENT PROCESS DEVELOPMENT BRANCH
        ADVANCED WASTE TREATMENT RESEARCH LABORATORY
           NATIONAL ENVIRONMENTAL RESEARCH  CENTER
              ENVIRONMENTAL  PROTECTION AGENCY
                   CINCINNATI,  OHIO
                      PRESENTED AT

THIRD U.S./JAPAN CONFERENCE ON SEWAGE TREATMENT TECHNOLOGY
                      TOKYO, JAPAN
                      FEBRUARY 1974
                            222

-------
              TREATMENT AND DISPOSAL OF SLUDGE FROM MUNICIPAL
                   WASTEWATER PLANTS IN THE UNITED STATES *
     Most communities in the United States have primary treatment and

secondary treatment is a national goal.  The quantities of sludge which

must be handled are large (Table l).   We expect a large increase in the

amount of secondary and chemical sludges.  As Table 1 shows, most of our

sludge is disposed to the land.  A substantial proportion is incinerated

and the ash is disposed to land.  Ocean disposal of sludge is expected to

be greatly reduced in the future.

Composition of Sludge

     Municipal sludge is chiefly composed of paper fiber, human wastes,

food wastes, a proportion of industrial wastes, and, when stormwater is

included in the sewers, soil and dirt from roads.  Raw sludges may contain

70 to 85 percent volatile solids (30 to 15$ ash) and digested sludge 50

to 65 percent volatile solids (50 to 35$ ash).  Sludge from a community

contains trace amounts of hazardous materials.  Typical values are

presented in Tables 2 and 3-  The range of values can be extremely high.

It is important that communities periodically analyze their wastewater

sludge to determine whether hazardous levels of certain contaminants will

place restraints on their method of disposal.

Ocean Disposal**

     The United States Council for Environmental Quality has spoken out

for an eventual cessation of the disposal of sewage sludge by barging to
*  Presented at Third U.S./Japan Conference on Sewage Treatment Technology,
   Tokyo, Japan, February 13, 1974.

** The author of this paper has not dealt intimately with ocean disposal and
   is not an authority on EPA's Ocean Dumping Policy.  The discussion is
   presented for general guidance only.
                                    223

-------
disposal sites in the ocean.  Most barging is conducted on our East Coast




where the sludge is dumped in the relatively shallow waters of the Con-




tinental Shelf.  Regulations have been published in the Federal Register^ '




and the Code of Federal Regulations^2' listing maximum concentrations of




certain metals and compounds which should not be exceeded in material




being dumped.  For example, it is stated that mercury in the solid phase




should not exceed 0.75 mg/kg-  Virtually any municipal sludge contains at




least several times this concentration of mercury.  There is pressure to




raise these levels but it is unlikely that changes will be made.  The




United States Environmental Protection Agency is issuing permits for




dumping of sewage sludges which are described as interim permits.




Municipalities are required to prepare a plan for meeting the desired




concentrations and reapply annually for a permit.  It is anticipated




that municipalities will find other disposal methods less costly than




meeting the ocean disposal regulations.  The EPA has prepared a report




describing the progress of the ocean dumping program'3/.




     For years, cities in California have discharged digested sludges by




pipeline to outfalls into the ocean.  There is essentially no continental




shelf on the Western Coast of the U. S.  Nevertheless, California has a




policy which will probably prohibit ocean disposal of sludges in the



foreseeable future.




Stabilization




     Anaerobic Digestion — There has been a renewed interest in anaerobic




digestion because of the energy shortage.  Most of the interest is related




to agricultural and animal wastes and municipal solid wastes.  The quantity
                                   224

-------
of recoverable methane from sewage sludge digestion is too low to have an




impact on the national needs.  However, it can help the economics of




individual plants.  Most wastewater treatment plants which utilize



anaerobic digestion waste the surplus gas over their needs for sludge



heating.  Los Angeles is a notable exception.  Both the city and the




county sell their excess gas production to nearby utilities.  There will



probably be more efforts made to utilize excess gas for in-plant power



generation and fuel needs.  Its impact will be small.




     Aerobic Digestion — Aerobic digestion is practiced at many small



plants where it is often followed by land disposal of liquid sludge.  We



have supported research work aimed at improving plant scale operation and



establishing design information*- '.  We have also supported work on thermo-



philic aerobic digestion (about 60° C) utilizing oxygen.  This work,



although in its early stages, has been encouraging.  It has the potential



of faster digestion (hence smaller equipment) and will produce a sludge



containing no pathogens.



     Chlorine Stabilization — Stabilization of sludge by treating it with



high concentrations of chlorine (about 2000 mg/l) produces a stable and



sterile sludge.  This process is being used at numerous small plants.  We



are concerned that the drainings from this sludge may contain toxic



chlorinated compounds.  We recommend that all drainings be recirculated



to the incoming sewage.



     Lime Stabilization — Our studies^) show that addition of lime to



liquid sludge will stabilize the sludge for a sufficiently long time to




permit nuisance-free disposal.  We now recommend adding lime to liquid
                                    225

-------
sludge to raise pH to 12.  This will require less than 0.15 kg Ca(OH)2




per kg of sludge (dry solids basis).  The sludge and lime are preferably




mixed by air, which removes the odor of ammonia.  Pathogenic bacteria are




eliminated.  The sludge can be dried on sand beds, disposed to a landfill,




or spread in liquid form on farm land.  It should not be discharged to a




lagoon or left in deep piles on the surface, because pH will eventually




drop and putrefaction can occur-




Microbiological Destruction




     The disposal of digested sludge to landfills should represent no




serious microbiological problem.  Solid waste is substantially higher




in pathogenic activity than digested sludges.




     When there is any large-scale disposal of digested sludge to agri-




cultural land, the question of microbial contamination is generally brought




forth.  If proper precautions are taken, there is no evidence of an undue




hazard.  In some countries, however, pasteurization is required during




the summer.  Recently, a plant utilizing nuclear isotopes to irradiate




sludge went on stream in Geiselbullach, Germany.  It is believed that




their concern is chiefly worm eggs and cysts.  It is possible that many




local jurisdictions will lean in the direction of extreme caution and




will require the equivalent of pasteurization for large scale agricultural




utilization of sludge.




Sludge Conditioning




     Chemicals -- The use of inorganic chemicals such as ferric chloride




and lime continues to lose ground.  Anionic, cationic, and nonionic




polymers are used in increasing amounts to condition sludges for the
                                   226

-------
elutriation process, for gravity and air flotation thickening, and for




dewatering.  The EPA has not found it necessary to stimulate development




in this field by grants and contracts.  Several very competent chemical




companies are engaged in research and development of polymer conditioning




agents and are heavily committed to developing this market.




     The use of polymers has made it possible to continue the use of




elutriation as a preliminary step for dewatering digested sludge.  When




primary and activated sludge are digested together, elutriation often




washes out a large proportion of fines.  These fines are returned to




process where they cause deterioration in effluent quality.  EPA con-




sidered making elutriation ineligible for construction grant funds.




However, the use of polymers has improved elatriation performance suffi-




ciently that it is still possible to get approval for construction grants




for elutriation facilities.




     Thermal Conditioning — The use of heat to condition sludge for




dewatering has seen rapid growth in recent years.  For example, from 1970




through about the first six months of 1973, Zimpro Division of Sterling




Drug installed or has under construction its low pressure sludge oxidation




system for a population equivalent of about 10 million people.  Other




companies such as Envirotech (Porteous Heat Treatment Process) have had




a similar experience.




     Experience of communities with sludge conditioning equipment is mixed.




Some communities are very pleased with the process whereas others have had




many difficulties.  The usual complaints are failure of equipment (often




related  to stones and metal in the sludge),  odor, excessive cost, and
                                   227

-------
high BOD load and color in the supernatant.  Limited bench-scale studies




at the Taft Center showed no substantial change in performance of the




activated sludge process when heat treatment supernatant was included in




the incoming primary effluent (COD load was held constant) except for a




persistent yellow color in the final effluent.  Zimpro and others^"/




have found that activated carbon removes this color effectively.




     The heat treatment of sludge has many vigorous advocates and equally




vigorous opponents.  It is this writer's opinion that, barring the unlikely




discovery that heat treatment causes formation of materials extremely




hazardous to health, heat conditioning of sludge is a viable wastewater




treatment process.  When its use is considered, its impact on the cost of




the entire processing sequence should be considered.  The bad experiences




at some plants indicate that manufacturer's recommendations of operating




and maintenance costs and off-stream time for repairs should be adjusted




upwards when cost estimates are made.




Dewatering




     High Solids — A new factor—the solids content of the dewatered




sludge—is becoming important in dewatering technology in the United States.




In the higher rainfall areas of the United States, sludge which is disposed




to a landfill should carry with it a minimum amount of water-  If the




dewatered sludge is relatively dry, it will be easier to handle and will




contribute less to leachate than a wetter sludge.   Several states have




put restrictions on solids content that range from general statements to




the effect that the sludge shall be easily handled by conventional land-




fill equipment to a specific statement by one state that the sludge shall




contain at least 50 percent dry solids.
                                    228

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     A second consideration which makes solid content important is the




energy shortage.  If sludge is being incinerated, supplementary fuel will




be needed during burning unless the solids content is above about 30 percent.




With the cost of desirable fuels such as gas and fuel oil expected to double




in price and often be unavailable, there will be heavy pressure to produce




a high solids dewatered sludge.




     Vacuum filters and centrifuges rarely produce cake solids greater than




about 22 percent solids when dewatering a mixture of primary and activated




sludges.  Pressure filters can produce sludge cake in the desired moisture




range.  Up until now, pressure filtration has been very slow in penetrating




the United States market, chiefly because the capital cost is so high.




     We are clearly in need of innovative means to produce dewatered sludge




with solids content in excess of 30 percent solids.  The development of




equipment which can remove additional water from sludge cake after it




leaves a centrifuge or vacuum filter is especially attractive.




     Belt Filters -- Two primary types of belt filters have become available




in the United States: the Carter Belt-Filter press and the Westinghouse




Capillary Suction Dewatering System.




     The Carter Belt-Filter press is a German development.  It comprises




three dewatering zones: initial draining, pressing, and shearing.  Sludge




is contained between two woven belts (0.2 to 1.5 mm openings).  Rollers




are carefully positioned to apply pressing and shearing action to the




sludge.  There were approximately 1,000 of these units installed in Germany




by 1971.
                                   229

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     The Westinghouse (infilco Division) Capillary Suction Dewatering




System has been developed with partial assistance from EPA.  It utilizes




a porous belt which removes water from sludge by "capillary suction."




Near the end of the belt travel, a smooth roll, driven at the same linear




speed as the belt presses against it.  The pressure forces additional




water from the sludge into the capillary belt.  The sludge cake transfers




to the smooth roll where it is scraped off and conveyed away.  This




device works well on sludges which are difficult to dewater.  Polymer




demands are low and production rate is high.  A demonstration unit is




being evaluated at St.  Charles, Illinois.




     Both of these devices offer possibilities of slightly higher sludge




solids than solid-bowl centrifuges or vacuum filters.  They are simple




to operate and should have low maintenance costs.




     Top-Feed Filter — Difficulty is often encountered in conventional




vacuum filtration with pickup from the sludge pan,  and with cake release.




Experiments have been conducted at Milwaukee with the aid of an EPA grant




with a vacuum filter in which the sludge pan was moved from the usual




4:00 o'clock to 8:00 o'clock position on the drum up to the 8:00 o'clock




to 11:00 o'clock position.  Difficulty encountered with sealing the pan




was overcome.  Sludge pickup was excellent.  Cake release also was excellent.




The cake release point was at the 8:00 o'clock position.  The force of




gravity was an important aid in removing cake from the filter cloth.




Cake solids and filter yield were increased.  A grant to demonstrate the




top-feed filter on a large scale has been made to Milwaukee.
                                   230

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     Centrifugation — Los Angeles County has demonstrated the utility of


a centrifuge of the vertical basket-type (solid wall basket) for removing


fine solids from sludge vith a high recovery.  The minimum cost method


for Los Angeles to improve the performance of their solid-bowl centrifuges


and produce a high solids cake was to process the centrate through the


basket-type centrifuge.  The basket-type centrifuge can give high recovery


of solids at low conditioning chemical cost.  However, cake solids is lower


than obtained with the solid-bowl centrifuge.


Disposal


     Incineration — An EPA Task Force conducted a series of tests on


sewage sludge incinerators and reported its results on air pollution and

                                                           (7\
metals concentration in particulates in a Task Force Reportv '.  The recom-


mendations of the Task Force are found in another publication'"'.  On the


basis of the above-mentioned tests, proposed standards of performance for

                                          (q\
new stationary sources have been published^'.  The standards specify only


that the exhaust gas contain less than TO mg/Wm3 (0.031 grain/dry scf) of


particulate matter.  This writer believes that in applying this standard,


wet scrubbing will be required, probably with a venturi-type scrubber or


similar (ca. 100 cm water pressure drop).  Some manufacturers maintain that


a low pressure drop scrubber (ca. 15 cm water) will clean the gases adequately


and are attempting to change this requirement.


     The Task Force on incineration recommended that afterburners be used


to insure that polychlorinated biphenyls and other organic materials are


destroyed.  The suggested conditions were l600° F (870° C) for 2.0 seconds


or a combustion condition that accomplishes the desired destruction.  Tests
                                    231

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by manufacturers indicate that an afterburner temperature of 1100° F

(590° C) and about 0.5 second accomplishes virtually complete destruction

of these materials when they are incinerated with sewage sludge in a

multiple hearth incinerator.

     Incinerators can be made to meet virtually any reasonable air pollu-

tion requirement without becoming extremely costly.  There is a report of

an incinerator being permitted in the San Francisco Air Pollution Control

District because it would produce less pollution than would the trucks

needed to transport the sludge cake to a suitable sanitary landfill.

     Landfill — Proposed guidelines have been published for land disposal

of solid wastes^  '.  These guidelines are not a binding obligation.  The

disposal of digested sewage sludges is permitted in sanitary landfills

where there is provision for handling these sludges.  The sludges must

be digested and must contain no "free" water ("free" water is not defined).

     Much sewage sludge is disposed by municipalities in what might be

called "private" landfills, but which are often nothing more than dumping

grounds.  It is our intent to promptly commence the development of an

environmentally acceptable procedure for disposal of sludge from small

wastewater plants to private landfills.

     Land Spreading — A critical review of land spreading practice in the

United States has been made^11' and will be published soon.  No detailed

discussion will be presented here.  Up until recently, most of our attention
                                   /
has been given to nitrogen as the factor that limits the rate of application

of sludges to the land.  For communities with a high proportion of industrial
                                   232

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wastes, the presence of certain metals which can be taken up by growing

crops will prevent the use of land spreading or limit loading rates to

uneconomical levels.  The loading levels of metals which are eventually

permitted in land spreading applications will decide whether this con-

serving use of sludge will be an economically viable alternative to other

disposal methods.
                                                 J. B. Farrell
                                                 January 31,
                                   233

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                              LITERATURE CITED


 1.  Federal Register,  38,  No. 198,  Part II,  "Ocean Dumping, Final Regula-
     tions and Criteria,"  Oct. 15,  19T3-

 2.  Code of Federal Regulations, 40 CFR,  220-227-

 3.  "Annual Report on the  Administration of  the Ocean Dumping Program,
     Fiscal Year 1973," pub.  U. S.  EPA.

 U.  Cohen, D. B.,  and J. L.  Puntenny,  "Metro Denver's Experiences with
     Large Scale Aerobic Digestion  of Waste Activated Sludge," presented
     at 47th Annual Conf. WPCF, Cleveland, Ohio, Oct. U,  1973-

 5.  Farrell, J. B., J. E.  Smith, Jr.,  S.  W.  Hathaway, and R. B. Dean,
     "Lime Stabilization of Chemical-Primary  Sludges at 1.15 MGD," presented
     at the 45th Annual Conf. WPCF,  Atlanta,  Georgia, Oct. 8-13, 1972.

 6.  Corrie, K. D., "Use of Activated Carbon  in the Treatment of Heat-
     Treatment Plant Liquor," Water Poll.  Control,  629-635 (1972).

 7.  U. S. EPA, "Report of  Task Force on Sewage Sludge Incineration,"
     Jan. 1972, available NTIS, No.  PB  211 323.

 8.  U. S. EPA, "Ocean Disposal Practices and Effects, A Report of a Meeting
     held by the President's Water  Pollution  Control Advisory Board, Sept. 26-29,
     1972," p. 22,  U. S. Govt. Printing Office: 1972-514-150 (126).

 9.  Federal Register,  3_8,  No. Ill,  June 11,  1973,  "Standards of Performance
     for New Stationary Sources, Proposed Standards for Seven Source Categories."

10.  Federal Register,  38,  No. 8l,  Part II, Apr. 27, 1973, EPA, 'Solid Waste
     Disposal: Proposed Guidelines  for  Thermal Processing and Land Disposal of
     Solid Wastes."

11.  Battelle Memorial Institute, Columbus, Ohio, Contract 68-03-0140, "A
     Critical Review of Experience  with Land  Spreading of Liquid Sewage Sludge,"
     to be published.
                                       234

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                                         TABLE 1:  MUNICIPAL SLUDGES FOR DISPOSAL
           QUANTITIES
ro
GO
en
SLUDGE TYPE



Primary (0.12 Ib/cap-da)

Secondary (0.08 Ib/cap-da)

Chemical (0.05 Ib/cap-da)



DISPOSAL METHODS



Landfill

Utilized on Land

Incineration

Ocean (Dumping and Outfalls)
                                                            POPULATION    TON/YR.
                                                              (MILL.)
          3,170,000


101       1,U80,000


 10          91,000
                                                                      1972
                         POPULATION    TON/YR.
(MILL.)


 170


 170


  50
                                                                               (% of Pof>ulation)
                                                                       20


                                                                       25

                                                                       15
3,720,000


2,^80,000


  ^55,000
                                   1985



                                    hO


                                    30


                                    30


                                     0

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    Metal

Beryllium

Cadmium

Chromium

Copper

Mercury **

Lead

Zinc
                           TABLE 2
               CONCENTRATION OF METALS IN SLUDGE —
                    SEVEN U. S. LOCATIONS
Median (mg/kg)

       0

     200

   1,800

   1,700

     4.5

   2,800

   1,600
Range (mg/kg)

    N.D. *

 N.D. to 800

 400 - 5,900

 900 to 6,000

 3-0 to 5-5

 800 to 6,900

 400 to 8,UOO
*  N.D. =  not detected

** Only 3 sludges analyzed
                             236

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Dieldrin




Chlordane




DDD




DDT




PCB
                               TABLE 3
                 PESTICIDE AND PCB LEVELS IN SLUDGES
Compound
Aldrin
Number of
Sites Sampled
3
Median
(mg/kg)
N.D. *
Range
(mg/kg)
16 (in on
 5




 5




 5




 5



10
 0.3



18.U




 0.2




 0.2




 2.8
 sample only)




0.08 to 2.0




3.0 to 32




N.D. to 0.5




N.D. to 1.1




N.D. to 105
   N.D. = not detected
                               237

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         EXPERIENCES WITH SLUDGE HANDLING  IN TEXAS
           DICK WHITTINGTON, P.E., DEPUTY DIRECTOR
                  TEXAS WATER QUALITY BOARD
                       AUSTIN, TEXAS
                       PRESENTED AT

THIRD U.S./JAPAN CONFERENCE ON SEWAGE TREATMENT  TECHNOLOGY
                       TOKYO, JAPAN

                       FEBRUARY 1974
                             238

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               EXPERIENCES WITH SLUDGE HANDLING IN TEXAS







       Texas,  located in the southwestern part of the United States,




is a large state covering 267,339 square miles (692,408 square kilometers.)(D





Some areas are highly urbanized, others are barely inhabited.  For example,




Dallas County  has a population density of about 1500 persons per square mile




(580 persons/square kilometer); while Kenedy County has a population density




of about 0.5 person per square mile (0.2 person/square kilometer.)(D  As a




consequence of the varying degrees of urbanization, Texas has both large sew-




age treatment  plants and very small sewage treatment plants—ranging in treat-




ment capacities from roughly 100 MGD (380,000 m /day) to 2000 gallons per day




(7.6 m3/day.)   This same factor dictates that plants are located in both




highly populated areas and very remote rural areas.  The climate in Texas




varies from humid in the East to arid in the West—rainfall variations from




roughly 50 inches per year (127 cm/year) to less than 8 inches per year (20




cm/year.)   These diversities lead to a host of sludge handling and disposal




techniques.




       The predominate sludge disposal technique utilized by small plants




in rural areas in Texas is anaerobic digestion with dewatering on open beds




and subsequent land application.  This technique is satisfactory and will




continue in popularity.




       At small plants in urban areas,  the trend is away from anaerobic




digestion and  toward aerobic digestion.  This trend is created by two




considerations:  (1) the extensive use of contact stabilization process
                                    239

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treatment plants and the amenability of aerobic digestion with this process,




and (2) nuisance problems associated with handling anaerobic sludges.





       Where small plants utilizing aerobic digestion are constructed




within economical hauling range of a large plant with sludge handling




capability, drying beds are not constructed—the excess sludge produced




being transported to a sludge plant for dewatering and disposal.  Since




many of these plants depend upon contract hauling of the sludge with the




attendant unreliability of transportation, difficulties have been experienced




with sludge buildup within the treatment process and subsequent deterioration




of effluent quality.  This is, of course, not inherent in the scheme—rather,




a defect in the management and implementation.





       The City of Houston employs a novel technique for transporting excess




activated sludge from plants with no dewatering facilities to a sludge process-




ing plant.  The City is located on the coastal plain which has a flat topo-




graphy.  Because of topography and other factors,  the City has thirteen




permanent sewage treatment plants and other temporary plants.  Only two




plants, the two largest, are equipped with sludge dewatering facilities.




The excess activated sludge from some of the plants is pumped via pressure




conduit to the nearest sanitary sewer which flows to the major plants equipped




with sludge dewatering facilities.  No problems have arisen as a result of




this transportation technique.





       Where sludge facilities are not within economical or practical




hauling distance, small treatment plants utilizing aerobic digestion are




equipped with sludge drying beds.  Difficulties have been encountered in




dewatering such sludges on drying beds—primarily the blinding of the bed.




In coping with this problem, operators have learned to draw sludge onto
                                    240

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the beds very slowly.  This permits the supernatant to flow over the




settled and settling sludge and drain through the sand bed ahead of the




encroaching sludge.  At some plants, arrangements have been made to fill




the bed, allow the sludge to settle, and decant the supernatant.  The




addition of polymers to the sludge as it is being drawn is reported to




help overcome the blinding of the bed.  The polymer is added to the aerobic




digester about 12 hours before drawing.^4^  The addition of polymers to the




sludge as it is being drawn is reported to help overcome this problem.





       At large plants in Texas, various sludge disposal techniques are




employed.





       The City of Houston, at the two major facilities previously




mentioned, utilizes the activated sludge process without primary sedi-




mentation.  The excess sludge is chemically conditioned with ferric chloride




 (75 Ibs. per ton of dry solids - 3.75%), dewatered on rotary vacuum filters,




flash dried and, subsequently, sold as a fertilizer under the name of




"Hou-Actinite."  The sludge to the filters typically average around 4%




solids, the filter cake about 15%, and the completely dried processed




sludge about 95.7%.^ '  The fertilizer typically has a moisture content of




around 5%; ash content of 35%; nitrogen content of 5%; and available phos-




phoric acid, 4%.(2)  The revenue to the City in the first six months of




1972 from fertilizer sales was reported to be $21 per ton (907 kg.) ^





       The City of Houston is presently building an additional 30-ton-per-




day (27,000 kg/day) sludge processing plant at its Alameda Plaza sewage




treatment plant.  This plant is to employ pressure filtration in lieu of




vacuum filtration ahead of flash drying.  In order to produce a filterable




sludge, the sludge must be conditioned with both ferric chloride and lime.(3
                                   241

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It is estimated that the pressure filter cake will have a solids content of




about 35% as contrasted to vacuum filter cake with a solids content of 15%.(3)




The increased solids content permits the drying step to be accomplished with




smaller flash dryers and a decreased fuel consumption.  The savings in drying




cost by using the pressure filters dictated the design change from vacuum




filters.  One disadvantage of the design change has been to lower the value




of the fertilizer produced.  This is brought about by the dilution of the




nutrient value of the fertilizer by lime used in sludge conditioning and




diatomaceous earth used to precoat the filters.  It is estimated that the




ash content will be increased to 49% and the nitrogen content lowered to




about 4%.(3)  The pressure filter-flash dryer system is estimated to save




the City about 2.5 million dollars over the next nine years.  '




       The Gulf Coast Waste Disposal Authority operates a large industrial




waste treatment plant in the Houston area known as the Champion plant.  The




plant treats paper mill waste with a small amount of other waste, primarily




petroleum refining waste.  The plant employs the activated sludge process and




has a treatment capacity of 44 mgd (166,500 m /day).





       Centrifuges are used to dewater excess activated sludge.   The dewatered




sludge is conveyed to barges moored in the ship channel for transportation to




ultimate disposal in lagoons constructed in the coastal wetlands.  The sludge




is conditioned with polymer prior to cer.trifugation.  A 20% solids cake is




generally produced.     The centrifuges in this operation experience unusually




high levels of abrasion wear.  This wear is attributed to the lime and titanium




content of the sludge derived from the paper-making process.^   Because of




the centrifuge problem and the likelihood that the lagooning operation in




the coastal wetlands will be declared unacceptable by the regulatory agencies,
                                     242

-------
the Authority is looking toward other sludge disposal techniques.  They have




tentatively decided upon pressure filtration and land filling.  The primary




factors influencing the decision to go to pressure filters over vacuum filters,




(2) chemical conditioning cost associated with vacuum filters, and (3) the




dryer cake produced by the pressure filters.(4)  The dryer cake facilitates




subsequent drying and/or incineration should these steps be ultimately required,




and also permits transportation of the cake in open dump trucks without drip-




ping liquids on the public roadways should an inland landfill site be chosen.





       The City of Austin Govalle sewage treatment plant utilizes lagooning




to dispose of its excess activated sludge.  The plant is a 40 mgd (151,400




m3/day) contact stabilization plant.  The lagoons are constructed above grade




and the only liquids they receive are excess activated sludge, the rain that




falls on their surface, and river water pumped into them to maintain a constant




water level.  River water pumpage is necessary to keep a constant water level




since the excess activated sludge is not sufficient to make up for evapora-




tion losses.  The ponds cover some 191 acres (77.3 hectares) and are so




constructed that they have a uniform depth of 8 feet *2.43 m) and smooth




sides with a 1/4 slope.  A paddle boat is provided to break up scum which




sometimes forms.  This system has worked extremely well and no problems




have been encountered with nuisance conditions.  In fact, the ponds are one




of the favorite areas of bird watchers in the winter when the ponds are




visited by great numbers of water fowl and shore birds.





       The City of San Antonio also employs sludge lagooning at its Rilling




Road plant.  This plant is a 94 mgd (355,790 m3/day) conventional activated




sludge plant.  Only the excess activated sludge is lagooned—the primary




sludge is subjected to anaerobic digestion and drying on open beds.  The
                                     243

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sludge lagoon is known as Mitchell Lake.  It is actually an articicial
impoundment covering some 850 acres (344 hectares) with a watershed area of
5000 acres (2023 hectares).   The lake has been in continuous service as a
sludge lagoon for 70 years,  and it is interesting to note that the sludge
accumulation over the lake bottom varies from about 3 feet  (.91 m) in the
upper and to about 1 foot (.305 m) in the lower end.  Nuisance conditions
frequently exist at this lagoon.  These conditions are created by extensive
shallows which are frequently exposed to the atmosphere by the fluctuating
water level in the lake.  The water level in the lake is allowed to fluctuate,
getting low in dry weather and overflowing in periods of adequate rainfall.
Due to the public dissatisfaction with Mitchell Lake, the City is presently
considering alternate sludge disposal techniques.
       It is our expectation that large plants in Texas in the more arid
portions of the State will continue to utilize sludge lagooning where feas-
ible.  In heavily populated areas where ultimate disposal is fertilizer
production or long distance landfill, particularly where the landfill must
be reached via public roads, we expect a trend away from vacuum filters to
pressure filters.  Where ultimate disposal is nearby landfill, vacuum filters
will most likely continue to be the most viable method of dewatering.

                                 REFERENCES
1.  A. H. Belo Corporation, Texas Almanac and State Industrial Guide, 1972-73.
2.  Bryan, A. C. and Garrett, M. T., Jr., What Do You Do With Sludge?  Public
    Works, December 1972.
3.  Binkley, James A., Engineering Report to the City of Houston Public Works
    Department - Sludge Disposal Methods, Almeda Plaza Sewage Treatment and
    Sludge Disposal Facilities, Job. No. 3304, September 10, 1971.
4.  Teller, Joe P., Personal Communication, December 5, 1973.
                                     244

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               PHYSICAL-CHEMICAL NITROGEN REMOVAL
                                   WASTEWATER TREATMENT
                          JESSE M. COHEN, CHIEF*
                     PHYSICAL-CHEMICAL TREATMENT SECTION
                    TREATMENT PROCESS DEVELOPMENT BRANCH
                ADVANCED WASTE TREATMENT RESEARCH LABORATORY
                  NATIONAL ENVIRONMENTAL RESEARCH CENTER
                           CINCINNATI, OHIO
                             PRESENTED AT

       THIRD U.S./JAPAN CONFERENCE ON SEWAGE TREATMENT TECHNOLOGY
                             TOKYO, JAPAN


                            FEBRUARY  1974
ENVIRONMENTAL PROTECTION AGENCY* Technology Transfer
                              July 1974
                 *The presentation was based on this Bulletin.
                               245

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                 ACKNOWLEDGMENTS
     This seminar publication contains materials prepared for the
U.S. Environmental Protection Agency Technology Transfer Program
and has been presented at Technology Transfer design seminars
throughout the United States.

     The information in this publication was prepared by Gordon
Gulp, representing Gulp, Wesner, Gulp—Clean Water Consultants,
Eldorado Hills, Calif.
                            NOTICE
     The mention of trade names or commercial products in this publication
is for illustration purposes, and does not constitute endorsement or recom-
mendation for use by the U.S. Environmental Protection Agency.
                             246

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                                   CONTENTS






                                                                                   Page



Introduction	248




Chapter I. Ammonia Stripping	249



Chapter II. Selective Ion Exchange   	257



Chapter III.  Breakpoint Chlorination	263



Chapter IV.  Comparison of Processes	267



References	268
                                          247

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                                   INTRODUCTION


     There are three basic physical-chemical nitrogen-removal techniques available for application
today. These three processes are

     • Ammonia stripping (ch. I)

     • Selective ion exchange (ch. II)

     • Breakpoint chlorination (ch. Ill)

     All of these approaches have the advantage that they are based on the removal of nitrogen in
ammonia form, which eliminates the costs of converting the ammonia to nitrate in the biologic-
treatment step. They also have the advantages that they are unaffected by toxic compounds that
can disrupt the performance of a biologic nitrogen-removal system, they are predictable in perform-
ance, and the space requirements for the treatment units are less than for biologic-treatment units.

     The advantages and disadvantages of each of these physical-chemical processes are discussed
in detail and the processes are compared in the chapters that follow. Discussion of these processes
includes application at the following facilities, either in existence or under design:

     • South Lake Tahoe, Calif.

     • Orange County, Calif.

     • Windhoek, South Africa

     • Blue Plains, B.C.

     • Upper Occoquan Sewage Authority, Va.

     • Rosemount, Minn.

     • North Lake Tahoe, Calif.

     • Montgomery County, Md.

     • Cortland, N.Y.
                                            248

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                                       Chapter I

                              AMMONIA STRIPPING
    The only nitrogen-removal process that actually has been used on a plant scale in wastewater
treatment is ammonia stripping.  This process has been in use for ammonia nitrogen at the South
Lake Tahoe plant for about 4 years. Both the advantages and limitations of this process have been
clearly demonstrated.

    The ammonia-stripping process itself consists of

    • Raising the pH of the water to values in the range of 10.8 to 11.5, generally with the lime
       used for phosphorus removal

    • Formation and re-formation of water droplets in a stripping tower

    • Providing air-water contact and droplet agitation by circulation of large quantities of air
       through the tower

The towers used for ammonia stripping closely resemble conventional cooling towers.

    Questions are sometimes raised concerning the fate of ammonia discharged to the atmosphere.
Are we merely converting a water-pollution problem to an air-pollution problem? Does  the
ammonia stripped from the wastewater cause an air-pollution problem or find its way back to the
receiving stream owing to scavenging by precipitation?

    The concentration of ammonia in the stripping-tower discharge is only about 6 mg/m3 for
domestic wastewaters (at an air flow of 500 ft3/gal and at an ammonia concentration of 23 mg/1
in the tower influent). As the odor threshold of ammonia is 35 mg/m3, the process does not
present a pollution problem in this respect.  The ammonia discharged to the atmosphere is a stable
material that is not oxidized to nitrogen oxides in the atmosphere.  The natural production and
release of ammonia as part of the natural  nitrogen cycle is about 50 billion tons per year. Roughly
99.9 percent of the atmosphere's ammonia concentration is produced by natural biological
processes.1  There is a large turnover of ammonia in the atmosphere, with the total ammonia content
being displaced once a week on the average. Ammonia is returned to the earth through gaseous
deposition (60 percent), aerosol deposition (22 percent), and precipitation (18 percent). Ammonia
is not considered an  air pollutant because there are no known public health implications, and
because it is a natural constituent of the atmosphere derived almost entirely from natural sources.
For example, a single cow releases as much nitrogen to the atmosphere in feces and urine as 12
people would contribute if all of their ammonia production were stripped to the atmosphere.

    There are no standards in the United States for ammonia concentrations in the atmosphere.
Some  foreign standards1 have been established.

    • Czechoslovakia, 100 mg/m3 (24 hours)

    • U.S.S.R., 200 mg/m3  (24 hours)

    • Ontario, Canada, 3,500 mg/m3 (30 minutes)


                                           249

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All of these standards are far above the 6 mg/m3 that will occur right at the tower discharge. The
process cannot be dismissed from consideration because of air pollution.

     A remaining question is the fate of the ammonia discharge to the air. Is it likely to find its
way into the receiving stream by being scavenged from the atmosphere by precipitation?

     Ammonia may be washed from air by rainfall, but not by snowfall.  The natural background
concentration of ammonia in the atmosphere is 5-7 ppb.  In rainfall the natural background ranges
from 0.01 to 1 mg/1, with the most frequently reported values of 0.1 to 0.2 mg/1.  The amount of
ammonia in rainfall is related directly to the  concentration of ammonia in the atmosphere.  Thus,
an increase in the ammonia in rainfall wuuld  occur only in that area where the stripping-tower
discharge increases the natural background ammonia concentration in the atmosphere.

     Calculations for the ammonia washout in a rainfall rate of 3 mm/h (0.12 in./h) have been
made for the Orange County, Calif., project.  The ammonia concentrations of ammonia in the
rainfall would approach natural background levels within 16,000 feet of the tower. Of course, the
ammonia discharge during dry periods diffuses  into the atmosphere quickly so that the background
concentration and resulting washout rate of ammonia at greater distances from the tower are not
affected during a subsequent storm. The ultimate fate of the ammonia that is washed out by rain-
fall within the 16,000-foot downwind distance depends on the nature of the surface upon which
it falls. Most soils will retain the ammonia. That portion which lands on paved areas or directly
on a stream surface will appear in the runoff  from that area. Even though a portion of the ammonia
washed out by precipitation will find its way into  surface runoff, the net discharge of ammonia to
the aquatic environment in the vicinity of the plant would be very substantially reduced.

     One of the great advantages of this method of nitrogen removal is its extreme simplicity.  Water
is merely pumped to the top of the tower at a high pH, air is drawn through the fill, and  the am-
monia is stripped from the water droplets.  The only control required is the proper pH in the
influent water. This simplicity of operation also enhances the reliability of the process.

     Several factors affect the efficiency of the ammonia-stripping process.

     •  Type of stripping unit

     o  pH

     •  Temperature

     «  Loading rate

     •  Scale of deposition

There are three basic types of stripping units now being used in full-scale applications.

     •  Countercurrent towers

     •  Crossflow towers

     •  Stripping ponds

Countercurrent towers (the entire airflow enters at the bottom of the tower while the water enters
the top of the tower and falls to the bottom) have been found to be the most efficient.  In the
crossflow towers, the air is pulled into the tower through its sides throughout the height  of the
                                          250

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packing. This type of tower has been found to be more prone to scaling problems. The stripping-
pond approach will be discussed in more detail later.

    The pH of the water has a major effect on the efficiency of the process. The pH must be
raised to the point that all of the ammonium ion is converted to ammonia gas.  The pH required
varies somewhat with temperature,2 but is generally about 11.0.

    Another critical factor is the air temperature.  The water temperature has  less effect on per-
formance because the water temperature reaches equilibrium with the air temperature in the top
few inches of the stripping tower. The efficiency of the process decreases as the temperature de-
creases.  For example, at 20° C 90 percent removal of ammonia is typically achieved. At 10° C,
the maximum removal efficiency drops to about 75 percent. When air temperatures reach freezing,
the tower operation must generally be shut down owing to icing problems.

    The hydraulic loading rate of the tower is also an important factor. This rate typically is ex-
pressed in terms of gallons per minute applied to each square foot of the plan area of the tower
packing. When the hydraulic loading rates become too high, good droplet formation is disrupted
and the water begins to flow in sheets. Tower loading rates of 2 gal/min/ft2 have been shown to be
compatible with optimum tower performance.2 It is critical that the water and air be uniformly
distributed over the tower area.

    Another factor that may have an adverse effect on tower efficiency is scaling of the tower
packing resulting from deposition of calcium carbonate from the unstable, high-pH water flowing
through the tower. The original crossflow tower at the South Lake Tahoe plant has suffered a
severe scaling problem. The severity of the scaling problem was not anticipated from the pilot
studies in which a countercurrent tower was used. As a result, the full-scale crossflow-tower packing
was not designed with access for scale removal in mind. Thus,  portions of the tower packing are
inaccessible for cleaning. Those portions that were accessible were readily cleaned by high-pressure
hosing. The potential scaling problem must be recognized in design. The use of countercurrent
towers and design of the packing with access for cleaning can adequately combat this problem.

    An example of design for scale control is the 15-mgd tower now under construction at the
Orange County, Calif., Water District plant (fig. 1-1). There the tower packing has been designed
to be readily removable for cleaning as a precaution against scaling problems, although no signifi-
cant scaling problem has been observed in several months of pilot tests at Orange County.3  Scaling
has also been reported not to be a significant problem at the Windhoek, South Africa, plant where
only a soft, easily removed scale was encountered.4 On the other hand, tests at the Blue Plains
pilot plant encountered a hard scale that was extremely difficult to remove.5 The hardness of the
scale at Blue Plains was affected by operating pH, with a harder scale forming at pH 11.5 than at
pH 10.8.

    Typical design criteria are

    •  Hydraulic loading, 1 to 3 gal/min/ft2

    • Air-to-water ratio, 300 to 500 ft3/min per gal/min

    • Air-pressure drop, 0.5 to 1.25 inches water

    •  Fan-tip speed, 9,000 to 12,000 ft/min

    •  Fan-motor speed, 1 or 2 speed

    • Packing depth, 20 to 25 feet
                                          251

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                    Figure 1-1.  Ammonia-stripping tower design. Orange County, Calif.
     • Packing spacing, 2 to 4 inches horizontal and vertical

     • Packing material, wood, plastic (Vfc-in. PVC pipe being used at Orange County)

     A curve for estimating the costs of the ammonia-stripping process for various-size plants is
presented in figure 1-2. This curve is based on a loading rate of 2 gal/min/ft2.  Because some applica-
tions may require ammonia removal only during warm weather months, operating costs are shown
for both 6-month and 12-month operation.

     The South Tahoe system is being modified to reduce the impact of temperature and scaling
limitations encountered at this plant.6 Basically, the modified process will consist of three steps
(see figs. 1-3,1-4, and 1-5).
                                           252

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      10.000
       5,000
       3,000
    °  2,000
    8
    u
    oT
    <
    o
        1,000
400

300


200
Operating and maintenance
12 months' operation
                                                       Operating and maintenance
                                                       6 months' operation
                                    I  I  I I  I
                             I
                                                   J	I
                                                                                   1,000
                                                                                   400
                                                                                   300
                                                                                   200
                                                             LJ

                                                       100   ^
                                                             <
                                                             5
                                                             Q
                                                             Z
                                                                           50
                                                       40
                                                                                   30
                                                                                   20
Z
I-
ir
LU
o.
O
                                                                                        Z
                                 5  6  7 8 910       20   30  40 50

                                      PLANT CAPACITY, mgd
                                                                        100
                                                                                 200
     Figure 1-2. Ammonia-stripping costs. (EPA STP Index = 200; includes engineering, legal, administrative,
                              construction financing, and contingencies.)
     • Holding in high-pH, surface-agitated ponds

     • Stripping in a modified, crossflow forced-draft tower through air sprays installed in the
       tower

     • Breakpoint chlorination

This system was inspired by observations in Israel of ammonia nitrogen losses from high-pH
holding ponds.7

     Pilot tests at South Tahoe indicated that the release of ammonia from high-pH ponds could be
accelerated by agitation of the pond surface. In the modified Tahoe system, the high-pH effluent
from the lime clarification process will flow to holding ponds. Holding pond detention times of
7-18 hours will be used in the modified South Tahoe plant.  The pond  contents will be agitated
and recycled 4-13 times by pumping the pond contents through vertical spray  nozzles into the air
above the ponds. At least 37 .percent ammonia removal is aniticipated, even in cold weather condi-
tions, in the ponds. The pond contents then will be sprayed into the forced-draft tower. The pack-
ing will be removed from the tower and the entire area of the tower will be equipped with water
sprays. At least 42 percent removal of the ammonia in the pond effluent is anticipated, based on
pilot tests, from this added spraying in cold weather, which will include recycling of the pond
effluent through the tower to achieve 2-5 spraying cycles. The ammonia escaping this process then
                                           253

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                                     ,,R SPRAYING OF RECYCLED POND WATER
                                        IN THE SECOND OF TWO PONDS
IN SECOND POND. TWO
  RECYCLE PUMPS
  34mgd CAPACITY
4'/. TO 13'A RECYCLES
            TWO HIGH pH PONDS IN SERIES
            7 TO 18 HOURS DETENTION TIME
                                                                            FLOW VARIES. 2 5 TO 7.5 mgd
     Figure 1-3.  Proposed new and modified ammonia nitrogen removal processes. South Lake Tahoe:
                                New high-pH flow-equalization ponds.
EXISTING CROSS FLOW AMMONIA
     STRIPPING TOWER
Figure 1-4.  Proposed new and modified ammonia nitrogen removal processes, South Lake Tahoe: Existing
                              stripping tower modified with new sprays.
         CO, OR Cl,
                                       CO,
                                                           Cl,
pH 10 8 i


^^^

^
4
h
«-^— ^^_^_ ^-._ ^^_j


i




	 >
s*^*^

™*W-*V_^>»

pH = 70



f EXISTING 2 STAGE NEW BREAKPOINT EXISTING 1 MG
t RECARBONATION CHLORINATION BALLAST POND
vmmJ BASIN CHAMBER FOR CHLORINE CON
pH = 70
TO FILTERS AND
CARBON COLUMN
TACT
     Figure 1-5.  Proposed new and modified ammonia nitrogen removal processes, South Lake Tahoe:
                                   Breakpoint chlorination (new).
                                               254

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will be removed by downstream breakpoint chlorination. The quantity of ammonia to be removed
by breakpoint chlorination will vary from 5 to 16 mg/1, depending on the plant flow and
temperatures.

     Another approach to overcoming the limitations of the stripping process has been developed
by CH2M/HILL Consulting Engineers.8  Although the process is only in its initial stages of develop-
ment, preliminary tests indicate it may be a significant advance in the state of the art of nitrogen
removal. It appears that the new process overcomes most of the foregoing limitations and has the
advantage of recovery of ammonia as a byproduct.

     The improved process, shown diagrammatically in figure 1-6, includes an ammonia-stripping unit
and an ammonia-absorption unit.  Both of these units are essentially sealed from the outside air but
are connected by appropriate ducting. The stripping gas, which initially is air, is maintained in a
closed cycle.  The stripping unit operates essentially in the same manner that is now being or has
been used in a number of systems, except that this system  recycles the gas stream rather than using
single-pass outside air.

     Most of the ammonia discharged to the gas stream from the  stripping unit is removed in the
absorption unit.  The absorbing liquid is maintained at a low pH to convert absorbed and dissolved
ammonia gas to ammonium ion. This technique effectively traps the ammonia and also has the
effect of maintaining the full driving force for absorbing the ammonia, since dissolved ammonia
    WASTEWATER
    CONTAINING _
    DISSOLVED
    AMMONIA (NH3)
                                         FAN (TYPICAL)
                                               I
    RECYCLE
    ALTERNATE  I
                                                         DUCTING (TYPICAL)
        PUMP
                   ~A   A   A  A
                       STRIPPING
                         UNIT
A A A A
ABSORPTION
   UNIT
                                               J
                             GAS STREAM-AMMONIA
                             REDUCED BY ABSORPTION
l.

 t
RECYCLED
ABSORBENT
LIQUID
                                                                 PUMP
                              WASTEWATER STRIPPED OF NEARLY
                           "*" ALL OR PART OF AMMONIA (NH3)
                                                                        ACID AND
                                                                        WATER MAKEUP
                      AMMONIUM SALT
                      SLOWDOWN (LIQUID
                      OR SOLID), OR
                      DISCHARGE TO STEAM
                      STRIPPER FOR AMMONIA
                      GAS REMOVAL AND
                      RECOVERY
                        Figure 1-6. Process for ammonia removal and recovery.
                                           255

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gas does not build up in the absorbent liquid. The absorption unit can be a slat tower, packed tower,
or sprays similar to the stripping unit, but will usually be smaller owing to kinetics of the absorption
process.

     The absorbent liquid initially is water with acid added to obtain low pH, usually below 7.0.
In the simplest case, as ammonia gas is dissolved in the absorbent and converted to ammonium ions,
acid is added to maintain the desired pH.  If sulfuric acid is added, for example, an ammonium sul-
fate salt solution is formed. This salt solution continues to build up in concentration and the
ammonia is finally discharged from the absorption device as a liquid or solid (precipitate) blowdown
of the absorbent. With current shortages of ammonia-based fertilizers, a salable byproduct may
result.

     Other methods of removal of the ammonia from  the absorbent may also  be applicable, depend-
ing on the acid used and the desired byproduct. Ammonia gas or aqua ammonia could be produced,
for example, by steam stripping the absorbent. In this case, acid makeup would be unnecessary.

     It is believed that the usual scaling problem associated with ammonia-stripping towers will be
eliminated by the improved process, since the carbon dioxide which normally  reacts with the cal-
cium and hydroxide ions in the water to form the calcium carbonate scale is eliminated from the
stripping air during the first few passes.  The freezing problem is eliminated owing to the exclusion
of nearly all outside air. The treatment system will normally operate at the temperature of the
waste water.
                                           256

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                                       Chapter II

                            SELECTIVE ION  EXCHANGE


    The selective ion exchange process derives its name from the use of zeolites that are selective
for ammonia relative to calcium, magnesium, and sodium.  The zeolite currently favored for this use
is clinoptilolite, which occurs naturally in several extensive deposits in the Western United States.
Studies of the process have been conducted by Battelle Northwest9 and the University of Cali-
fornia.10  Clinoptilolite used in studies conducted by Battelle Northwest for EPA was obtained
from the Hector, Calif., leases  of the Baroid Division of the National Lead Company, Houston, Tex.
The clinoptilolite is crushed and sieved to obtain a 20 by 50 mesh size. Ammonia is removed by
passing the wastewater through a bed of clinoptilolite at a rate of about 10 bed volumes per hour.

    The use of clinoptilolite was investigated at the University of California with the objective of
optimizing its application to ammonia removal from wastewaters. Pilot-plant operations were
carried out at three different municipal sewage-treatment plants. An average ammonia removal of
96 percent was obtained in these operations with influent ammonia nitrogen concentrations of
about 20 mg/1.

    The ammonia capacity of the clinoptilolite was found to be nearly constant over the pH range
of 4.0 to 8.0, but diminished rapidly outside this range.  The effect of wastewater composition on
the ammonia exchange capacity was analyzed by exhausting clinoptilolite beds with waters having
different chemical compositions.  For relatively constant influent ammonia concentrations, the
ammonia exchange capacity was observed to decrease sharply with increasing competing action con-
centrations up to about 0.01 molar.  Increases of cation concentrations above this value continued
to decrease the exchange capacity, but to a much lesser degree. Ammonia removal to residual levels
less than 0.5 mg/1 ammonia nitrogen is technically feasible, but only with shorter service cycles and
greater regeneration  requirements. Flow rates in the range of 7.5 to 15 bed volumes per hour had
no effect on ammonia effluent values.

    Battelle Northwest conducted pilot  studies of the clinoptilolite process applied to secondary
effluents, advanced waste treatment effluents, and clarified raw sewage.9 -11  Ammonia removals
ranging from 93 to 97 percent were demonstrated using a 100,000-gal/d mobile pilot plant.  These
studies were conducted at several different locations across the United States.

    After about 150-200 bed volumes of normal-strength municipal waste have passed through the
bed, the capacity of the clinoptilolite has been used to the point that ammonia begins to leak through
the bed. At this point, the clinoptilolite must be regenerated so that its capacity to remove ammonia
is restored.

    The key to the  applicability of this process is the method of handling the spent regenerant. The
resin is regenerated by passing concentrated salt solutions through the exchange bed when the am-
monia concentration has reached the maximum desirable level. Following regeneration, the
ammonia-laden spent-regenerant volume is about 2.5 to 5 percent of the throughput treated before
regeneration.
                                            257

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     The original approach to recovering and reusing the regenerant was to use a lime slurry as the
regenerant so that the ammonium stripped from the bed during regeneration would be converted to
gaseous ammonia, which could then be removed from the regenerant by air stripping.9

     Regeneration with lime alone was found to be a rather slow process; therefore, the ionic
strength of the regenerant solution was increased by the addition of salt (NaCl). The increased
ionic strength of the regenerant plus the presence of sodium ion accelerates the removal of ammonia
from the zeolite. Although most of the sodium chloride added to the regenerant is converted to
calcium chloride by continuous recycle of the regenerant, sufficient sodium ion remains under
steady state conditions to promote  the elution of the ammonium ions.  The sodium ion has a
higher diffusion coefficient than calcium ion, which is believed responsible for increasing the am-
monia elution rate. With the lime-slurry regenerant, the regenerant stripping tower handles only a
small fraction of the total plant throughput. Heating the stripping tower, even during cold weather
periods, is then practical.

     The use of the high-pH regenerant is accompanied by an operational problem. Some plugging
of the bed with Mg(OH)2 and CaCO3 occurs when the high-pH regenerant is used. Attrition of the
zeolite is aggravated by the violent backwashing needed to remove these solids, and is 0.17-0.25
percent per cycle, making makeup clinoptilolite costs a significant factor. These problems make more
recently developed methods of regenerant recovery more attractive.

     In one approach, ammonia in the regenerant solution may be converted to nitrogen gas by
reaction with chlorine which is generated electrolytically from the chlorides already present in the
regenerant solution. This process can be carried  out with a regenerant of neutral pH so that the
problem of precipitation of Mg(OH)2 and CaCO3 within the bed during regeneration is eliminated.
Also, cold weather does not affect the regenerant recovery process.  The regenerant solutions used
are rich in NaCl and CaCl2 which provide the chlorine produced at the anode of the electrolysis
cell.  The reactions for the destruction of ammonia by chlorine are the same as for breakpoint
chlorination.

     During regeneration of the ion exchange bed,  a large amount of calcium is eluted from the
zeolite along with the ammonia. This calcium may be removed from the spent regenerant solution
by soda ash softening before passing the spent regenerant through the electrolytic cells.  The soften-
ing step would lower the calcium concentration below the  level that would cause calcium hydroxide
formation in the electrolytic cells. High flow velocities through the electrolysis cells are required in
addition to a low concentration of MgCI2 to minimize scaling of the cathode by calcium hydroxide
and calcium carbonate. Acid flushing of the cells would be necessary to remove this scale when the
cell resistance becomes too high for economical operation.

     In pilot tests of the electrolytic treatment of the regenerant at Blue Plains, Battelle Northwest
found that about 50 Wh of power were required to destroy 1 gram of ammonia nitrogen (NH3-NT).
When related to the treatment of water containing  25 mg/1 NH3-N, the  energy consumed would be
4.7 kWh per 1,000  gallons.  Tests at South Tahoe also indicated that a value of 50  Wh per gram is
reasonable for design.12  Preliminary capital and operating costs of $1.5 million and 9 cents per
1,000 gallons, respectively, were estimated by Battelle for  a 10-mgd plant using electrolytic destruc-
tion of ammonia in recycled regenerant containing chloride salts of calcium, sodium, and magnesium.
Electrolytic treatment of the regenerant avoids the disposal of ammonia to the atmosphere or dis-
posal of aqueous ammonia concentrates.  Total costs, including capital amortization, were estimated
at 12.7 cents per 1,000 gallons.11

     A 22.5-mgd plant designed by CH2M/HILL for the Upper Occoquan Sewage  Authority in the
State of Virginia will employ selective ion exchange with electrolytic treatment of the regenerant
for ammonia removal. This plant will utilize soda ash softening of the regenerant to avoid cathodic
scaling of the electrolysis cells. A simplified flow schematic of the regeneration system is illustrated
                                           258

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in figure II-l. The regeneration of the clinoptilolite beds will be accomplished with a 2-percent
solution of NaCl. The spent regenerant will be collected in a large holding tank to minimize varia-
tion in the calcium content before soda ash addition for calcium removal. After the soda ash addi-
tion, the regenerant will be clarified and transferred to another holding tank where the regenerant
will be recirculated through electrolysis cells for ammonia destruction.

     Design criteria for the ammonia-removal plant for the Upper Occoquan District are summarized
in table II-l.  The electrolysis cell to be used by this plant is a 500-Ampere unit manufactured by
Pacific Engineering and Production Company of Nevada, Henderson, Nev. The cell consists of a
lead dioxide coated graphite anode in a cylindrical stainless steel vessel which is the cathode.  The
lead dioxide is highly resistant to attack by chlorine or  oxychloroacids. The estimated total cost
for this plant is 12.6 cents per 1,000 gallons for the selective ion exchange process.

     In order to develop the design criteria for the Occoquan plant, CH2M/HILL conducted pilot
tests of the process at the South Tahoe plant.12  The ammonia concentration in the wastewater at
South Tahoe ranged from 21 to 28 mg/1 during these pilot tests.  After about 6 weeks of pilot-plant
operation, the calcium concentration of the influent increased from about 55 mg/1 to about 80  mg/1.
This increased calcium concentration together with concurrently occurring lower influent tempera-
tures reduced the quantity of ammonia that could be loaded onto the clinoptilolite before a break-
through of 1  mg/1 of ammonia. The average loading to the clinoptilolite column before breakthrough
of 1 mg/1  of ammonia was 144 bed volumes with an influent containing 55 mg/1 calcium at 22°  C.
When the influent calcium increased to 80 mg/1 and the temperature dropped to 14° C, the loading
capacity of the clinoptilolite column dropped to 104 bed volumes. Ammonia removals achieved
were in excess of 95 percent.
                                  Na2CO3
                                  NaOH
         ZEOLITE
         BED
SPENT
REGENERANT
HOLDING
TANK
                                         CLARIFIER
                                                                    REGENERANT
                                                                    OUT
                                                                         ANODE
RENOVATED
REGENERANT
HOLDING
TANK
                                          SLUDGE
                               REGENERANT
                                                                          on
                                                                          CO
                                                                          O
                                                                          DC
LU -J
-I UJ
01 O
                                                               REGENERANT
                                                               IN
                                                                            CATHODE
                                                                            RECTIFIER
             Figure 11-1.  Simplified flow diagram of Upper Occoquan regenerant treatment system.
                                            259

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        Table \\-1.-Design criteria for the Upper Occoquan ammonia removal plant at 22.5-mgd flovj rate
Exchange beds:
    Size and type
    Number	
    Media  	
    Media size  	
    Bed depth  	
    Bed length 	
    Bed width  	
    Service cycle loading:
        Average	
        Maximum  	
    Hydraulic loading:
        Average	
        Maximum  	
    Flow:
        Average	
        Maximum  	
    Length of service cycle
    Bed loading  	
    Backwash water	
    Backwash rate	
Exchange-bed regeneration:
    Length of cycle	
    Regeneration rate  . . .
Regenerant recovery:
    Method  	
    Power requirement	
    NH3 destruction rate  	
    Number of electrolytic cells in service
    Total number of cells provided	
    Rectifiers:
         Number  	
         Capacity	
    Salt requirements	
10-foot-diameter X 50-foot-long horizontal
  pressure units
8
Clinoptilolite
20 X 50 mesh
4 feet
50 feet
10 feet

9.1  BV/h
14.1 BV/h

4.4 gal/min/ft2
6.9 gal/min/ft2

3.2 mgd per bed
5 mgd per bed
200 BV
365 pounds NH3 per bed cycle
Carbon-column effluent
8 gal/min/ft2
3.1 hours
10 BV/h
Electrolysis
40 Wh per gram NH3-N destroyed
0.16 pound NH3-N per hour per cell
480
720

3
750 kW
13,900 Ib/d
     The pilot column was regenerated successfully with a 2-percent sodium chloride solution at
neutral pH. No loss of Clinoptilolite by attrition was observed when using the neutral regenerant,
and no difficulties in backwashing were observed.  Although the neutral regeneration scheme was
found to involve 30-40 bed volumes of regenerant rather than the 10 or less needed by others with
the high-pH schemes, the minimization of attrition losses is achieved without significant disadvan-
tage.  The closed-loop regenerant-recovery system  results only  in added downtime for regeneration.

     Scaling within the electrolytic  cell used for regenerant recovery was the primary concern of the
Occoquan pilot-plant study; therefore, the electrolytic cell was routinely dismantled and inspected
for scaling.  The flow rate through the cell was set initially at velocities of 0.13 to 0.16 ft/s, and a
thin  buildup of scale was observed on the cathode at the bottom-cell-inlet end after 160 hours of
operation.  After 230 hours  of operation, the flow velocity was reduced to 0.06 ft/s,  and very light
scale buildup was observed depositing over the entire cathode area.
                                              260

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    Scale was removed from a 1-in.2 area of the cathode, and the flow velocity through the cell
was increased to 0.21 ft/s to determine the effect of scaling at higher cell velocities.  At this in-
creased flow, which was maintained for most of the period of the pilot-plant study, no new scale
was deposited on the cathode.  Visually, it appeared that from 25 to 50 percent of the previously
deposited scale was removed. These observations suggest that scaling within the cell can be con-
trolled by sufficient flow velocities. The average power requirements for regenerant recovery were
measured as 43.3 Wh per gram ammonia destroyed. To allow for normal system losses, a design
value of 50 Wh/g appears reasonable.

     An alternative to air stripping or electrolysis of the regenerant is steam stripping. A 0.6-mgd
plant in Rosemount, Minn., which is now entering its startup period, utilizes this technique.13'14
At Rosemount ammonia is recovered from the spent ion exchange regenerant in an ammonia
stripper.  Steam is injected into a distillation column countercurrent with the  regenerant solution
to strip off the ammonia.  An air-cooled plate-and-tube condenser then condenses the vapor for
collection in a covered tank as 1-percent aqueous ammonia for sale as a fertilizer,  However, it is
a dilute (1 percent) ammonia solution, which reduces its potential for sale as a fertilizer, since
commercial fertilizers require handling of only 1/10 the volume of liquid for the same ammonia
application.

     No  detailed data on the Rosemount design and anticipated operating parameters were available
at the time of this report.  An EPA evaluation of the plant will be made in 1974 after the initial
shakedown problems are resolved.  The steam-stripping process is based on the use of the high-pH
regenerant, which has the  disadvantages noted earlier.  Battelle Northwest's evaluation of steam
stripping3 indicates that it is economically feasible if the regenerant volume is held to 4  bed volumes
per cycle, which is achievable with high-pH regenerant. The steam requirements were estimated to
be 15 pounds per 1,000 gallons.  At a steam cost of $2 per 1,000 pounds, the steam costs would
be only 0.03 cent per  1,000 gallons.  Heat recovery by contacting the cold regenerant with stripped
regenerant and by contacting it with the condenser would be necessary to  achieve  economical
operation.  Because of the unstable, high-pH regenerant, scaling problems on the heat exchanges
could be anticipated.

     Another technique for  regenerant recovery is the  use of the stripping-recovery process (shown
in fig. 1-4) on the spent regenerant. A 6-mgd plant at North Lake Tahoe is being designed using
this approach. Tests to date indicate that ammonia sulfate concentrations of  50 percent are readily
achievable in the absorption tower. The estimated costs of the selective ion exchange approach based
on  this technique of regenerant recovery are shown in  figure II-2. No credit for potential sale of
ammonium sulfate has been included.
     aB. W. Mercer, BatteP.e Northwest, personal communication, Dec. 14, 1973.
                                            261

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   20,000
   10,000
    5,000
o   3,000

x


I   2,000
o
T3
CO
O
O
E
<
O
1,000






 500

 400


 300



 200
                                                           Capital
                 Operating and maintenance
                               J	L
                                         I   I  i I
                                                            JL
J	L
                                                                                              2,000
                                                                                             1,000
                                                                                              500

                                                                                             400
                                                                                                 300
                                                                                             200
                                                                                                 100
                                                                                                 50

                                                                                                 40


                                                                                                 30



                                                                                                 20
                                4   5  6 7 8 910
                                                          20
                                                                30   40  50
                                                                                100
                                                                                          200
                                        PLANT CAPACITY, mgd
                                                                                                        o

                                                                                                        X
                                   05

                                   CO
                                   O
                                   o
                                   LU
                                   O

                                   <

                                   LU

                                   z
                                   5

                                   Q

                                   <

                                   U
                                   Z


                                   <
                                   DC
                                   LU
                                   CL
                                   O
                                   Z
  Figure 11-2.  Ammonia removal by selective ion exchange. (EPA STP Index = 200; includes engineering, legal,

                         administrative, construction financing, and contingencies.)
                                                   262

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                                     Chapter  III

                         BREAKPOINT CHLORINATION
    When chlorine is added to a waste water containing ammonia nitrogen, ammonia reacts with
the hypochlorous acid formed to produce chloramines. Further addition of chlorine to the break-
point converts the chloramines to nitrogen gas.  The chlorine and ammonia reactions in dilute
solutions are

                    NH4 + HOC1 -»• NH2C1 (monochloramine) + H2O + H+

                       NH2C1 + HOC1 -* NHC12 (diochloramine) + H2O

                     NCH12 + HOC1 -» NC13 (nitrogen trichloride) + H2O

    The reactions are dependent on pH, temperature, contact time, and initial chlorine-to-ammonia
ratio.  Chlorine is added to the wastewater being treated until the chlorine residual has reached a
minimum (the breakpoint) and the ammonia is'removed.  A typical breakpoint curve is shown in
figure III-l. The reaction with ammonia is very rapid. Less than 1 minute, in the pH range of 7.0
to 8.0, and all of the free chlorine is converted to monochloramine at a 5:1 weight ratio of
chlorinerammonia nitrogen. As the weight ratio exceeds 5:1, the monochloramine breaks down and
forms dichloramine and ammonia,

                                 2NH2Cl->-NHCl2 +NH3

Monochloramine is then oxidized by excess chlorine under slightly alkaline conditions to nitrogen
gas,

                           2NH2C1 + HOC1 ->• N2t +3HC1 + H2O

Stoichiometrically, a weight ratio of 7.6:1 of chlorine to ammonia nitrogen is required to oxidize
ammonia to nitrogen gas.

    Breakpoint chlorination tests on domestic wastewaters at the Blue Plains plant indicate that
95 to  99 percent of the ammonia is converted to nitrogen gas and that no. significant amount of
nitrous oxide is  formed.15  The quantity of chlorine required to achieve breakpoint was found to
decrease with an increasing degree of treatment before the breakpoint process.  The quantity of
chlorine required for breakpoint chlorination of raw wastewater was found to be 10 parts by weight
of C12 to 1 part of NH3 nitrogen. This ratio decreased to 9:1 C12 :NH3 nitrogen for secondary
effluents, and 8:1  C12 :NH3 nitrogen for lime-clarified and filtered  secondary effluent. The Blue
Plains tests found that the chlorine dose was minimized at pH values between 6.0 and 7.0.  The
minimum NO3 production (1.5 percent of the NH3-N) occurred at pH 5.0. At pH 8.0, the nitrate
production increased to 10 percent of the influent NH3 nitrogen.  NC13 production at the break-
point  decreased from  1.5 percent to the influent at pH 5.0 to 0.25 percent at pH 8.0.  Temperature
did not affect the product distribution or  the required chlorine dose in the range 5° to 40° C.
                                          263

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             10 1
                             0.5
                                     MOLE RATIO, CI2 : NH4-I\I

                                            1             1.5
                               COMBINED CHLORINE
                             RESIDUALS PREDOMINANT
FREE CHLORINE
  RESIDUAL
 PREDOMINANT
                           23456789

                                     CHLORINE DOSAGE, mg/|

                          Figure 111-1. Typical breakpoint-chlorination curve.
                                                                      10
                                                                            11
                                                                                 12
     The use of chlorine produces an equivalent weight of hydrochloric acid which may depress the
pH of the wastewater unless the natural alkalinity is adequate or a base such as sodium hydroxide is
added.  If the pH is allowed to fall, highly odorous nitrogen trichloride (NC13) is formed, which is
an intolerable end product.  If a base is used to prevent pH depression, the mixing of the wastewater,
chlorine, and base must be extremely violent to avoid local areas of low pH which would generate
NC13.  Tests at  Blue Plains showed that eductors do not give adequate chlorine-wastewater mixing,
which did result in localized low-pH regions in which objectionable quantities of NC13 formed.
Violent mechanical mixing is required.  The use of sodium hypochlorite rather than chlorine does
not depress the pH and avoids the foregoing problem.

     The use of chlorine gas may produce more acid than can be neutralized by the wastewater.
According to the EPA study reported by Pressley,15 14.3 mg/1 of alkalinity (as CaCO3) are required
to neutralize the acid produced by the oxidation of 1 mg/1 NH3-N to N2.  Either sodium hydroxide
or lime may be  used for pH control if the wastewater is deficient in alkalinity. A wastewater con-
taining 25 mg/1 NH3-N requires an alkalinity of about 357 mg/1 if chlorine gas is used.

     A significant factor in considering this process for application in some cases is the addition of
dissolved solids inherent to the process. If, for example, chlorine gas were used and the influent
ammonia nitrogen concentration were 25 mg/1, the dissolved solids would be increased by 156 mg/1.
Neutralizing with lime would result in a total increase of 306 mg/1 of total solids.  If the chlorinating
agent were sodium hypochlorite, the increase in dissolved solids would be  177 mg/1.16
                                            264

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    The effects of breakpoint chlorination on organic nitrogen are somewhat uncertain. The Blue
Plains tests15 found only a "slight reduction in organic nitrogen within the two hour contact time."
Other tests17 observed a decrease in organic nitrogen content as the C12:N ratio increased.  Reduc-
tions from 3.2-3.5 mg/1 to 0.2-0.4 mg/1 organic nitrogen were reported for the breakpoint process.
The authors,17 however, felt that such apparent removals result from an analytical anomaly in
which the organochloramine formed is not measured as nitrogen in the Kjeldahl organic nitrogen
analysis. At higher chlorine dosages, however, their literature review indicated that organochloramines
will be oxidized to aldehydes and nitrogen gas. The breakpoint reactions of organochloramines pro-
ceed more slowly than the ammonia chloramines, and probably will not be complete in a 30-minute
contact time.

    Several recent studies16'17'18-19 have investigated the possibility of adding only enough
chlorine to form monochloramines and then removing the monochloramines on activated carbon.
Some advantages would be realized if monochloramine could be removed by activated carbon.  The
theoretical C1:N ratio for 100 percent ammonia removal  would drop from 7.6:1 for breakpoint to
about 5:1  for the formation of monochloramine.  The dissolved solids added to the system and the
alkalinity requirements would be significantly reduced. Two studies16'17 found that ammonia
removals of about 50 percent could be achieved at C1:N ratio of 5:1 when the breakpoint process
was followed by activated-carbon adsorption. Complete removal still required dosages of about 9:1
in three studies.16'17'18  Carbon contact times of 10 minutes were found to be adequate for com-
plete dechlorination of the effluent.16

    Experiences with the breakpoint process in South Africa20 confirm that automatic control of
the process is important. The African researchers concluded that monitoring of the ammonia
coupled with automatically controlled chlorine dosing is a necessity.  A successful,  automated-
computer-control system has been developed and demonstrated at the Blue Plains pilot plant.21
This system matches the quantity of chlorine fed to the quantity of incoming nitrogen, and also
controls the pH to 7.0 to minimize the formation of NC13 and NO3.  (See fig. III-2.)

    There are several projects in the design or construction stage utilizing the breakpoint-chlorina-
tion process. The 7.5-mgd. South Lake Tahoe plant  is adding facilities to provide breakpoint chlorina-
tion of the quantities of ammonia which escape the  upstream nitrogen-removal processes (5-16  mg/1).6
The Orange County, Calif., 15-mgd wastewater reclamation plant now nearing completion will
include facilities to remove the 2-3 mg/1 of ammonia that will escape the upstream ammonia-stripping
process.22 Chlorine gas will be supplied from purchased 1-ton cylinders and by an  on-site electrolytic
generator rated at 2,000 Ib/d. The chlorine generation system will utilize an electrochemical cell
to electrolyze sodium chloride brine to chlorine gas  and sodium hydroxide solution. The sodium
hydroxide solution will be used in an adjacent sea water desalting plant.

    A 60-mgd facility is under design for Montgomery County, Md., by CH2M/HILL, which will
utilize the breakpoint process as the primary nitrogen-removal process. In this plant, sodium hypo-
chlorite will be produced on site by electrolysis of a salt brine. The Cortland, N.Y., 10-mgd
physical-chemical plant design includes facilities for breakpoint chlorination of the  portion of the
flow required to meet stream standards.

    The costs of the process applied to the 309-mgd plant at Blue Plains were estimated at 6.7 cents
per 1,000 gallons, with chemical costs constituting 5.9 cents of this value. These costs were based
on a chlorine cost of only $75 per ton and a dose of only 120 mg/1. The control of pH was assumed
to be by lime addition (1 pound of lime per pound of chlorine) at a lime cost of $24 per ton. In any
case, the cost of the chlorine itself constitutes a large portion of the total project costs.  Assuming a
chlorine cost of 0.07 cent per pound and a C1:N ratio of 8:1, the chlorine cost for removal of 25
mg/1 ammonia would be 11.8 cents per 1,000 gallons.  The chlorine demand for this dose is equiva-
lent to  1,668 Ib/mg.
                                            265

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   INFLUENT
                          Figure 111-2.  Breakpoint-chlorination control system.
     The breakpoint process is useful for eliminating low concentrations of ammonia as a polishing
step following another nitrogen-removal process.
                                            266

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                                      Chapter IV
                         COMPARISON  OF  PROCESSES
    Each of the processes discussed earlier has its advantages and disadvantages. Unfortunately,
no single process for nitrogen removal is superior to others both in terms of performance and
economics.

    The ammonia-stripping process has the advantages of low cost, removal of ammonia with a
minimal addition of dissolved solids, simplicity, and reliability.  However, it has the disadvantages
of poor efficiency in cold weather and the potential for scaling problems that may reduce its effi-
ciency, and it raises concerns, whether valid or not, over ammonia gas discharge.  The new stripping-
recovery system overcomes many of these problems, but at the sacrifice of low process costs.

    The selective ion exchange process has the advantages of high efficiency, insensitivity to tem-
perature fluctuations,  removal of ammonia with a minimal addition  of dissolved solids, and the
ability to eliminate any discharges of nitrogen to the atmosphere other  than nitrogen gas.  This
process has the disadvantage of relatively high cost, and process control and operation are relatively
complex.

    The breakpoint chlorination process has the advantages of low  capital cost, a high degree of
efficiency and reliability, insensitivity to cold weather, and the release of nitrogen as nitrogen gas.
It has the disadvantage of adding a substantial quantity of dissolved  solids to the effluent in the
process of removing the ammonia, it will raise public concerns over handling of chlorine gas, the
process controls required are relatively complex, and it requires a downstream dechlorination
process.

    The relative costs of the physical-chemical nitrogen processes for a 10-mgd plant are

    • Ammonia stripping, 5 cents per 1,000 gallons
       Selective ion exchange, 10-13 cents per 1,000 gallons

       Breakpoint chlorination, 11 cents per 1,000 gallons
These costs all are based on the removal of 25 mg/1 ammonia nitrogen.  The cost of biological
nitrogen removal by the three-stage activated-sludge process has been estimated23'24 at about 13
cents per 1,000 gallons.  Preliminary estimates on the costs of the new ammonia-stripping/ammonia-
recovery process discussed earlier, which minimizes the seasonal restrictions on the ammonia-
stripping process, indicate that the cost will be 8-10 cents per 1,000 gallons.  It can be seen from
the above  costs that there is little economic incentive to select one process over another if faced
with a requirement for cold weather removal of ammonia.  The choice must be made by weighing
the advantages and disadvantages of each approach in light of the circumstances applicable to a
specific project.
                                            267

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                                     REFERENCES
     1S. Miner, "Preliminary Air Pollution Survey of Ammonia," U.S. Public Health Service,
Contract No. PH22-68-25, Oct. 1969.
     2A. F. Slechta and G. L. Gulp, "Water Reclamation Studies at the South Tahoe Public Utility
District," J. Water Pollut. Cont. Fed., 39, 787, May 1967.
     3G. M. Wesner and R. L. Gulp, "Wastewater Reclamation and Seawater Desalination," J. Water
Pollut. Cont. Fed., 44, 1932, Oct.  1972.
     4R. B. Dean, ed., Nitrogen Removal from Wastewaters, Federal Water Quality Administration
Division of Research and Development, Advanced Waste Treatment Research Laboratory, Cincinnati,
Ohio, May 1970.
     5T. P. O'Farrell  et al., "Nitrogen Removal by Ammonia Stripping," J. Water Pollut. Cont.
Fed., 44, No. 8, 1527, Aug. 1972.
     6 J. G. Gonzales and R. L. Gulp, "New Developments in Ammonia Stripping," Pub. Works,
May and June 1973.
     7Y. Folkman and A. M. Wachs, "Nitrogen Removal Through Ammonia Release from Ponds,"
Proceedings, 6th Annual International Water Pollution Research Conference, 1972.
     8L. G. Kepple, "New Ammonia Removal and Recovery Process," Water Waste, in press, 1974.
     9Battelle Northwest, "Ammonia Removal From Agricultural Runoff and Secondary Effluents
by Selective Ion Exchange," Robert A. Taft Water Research Center Rep. No. TWRC-5, Mar. 1969.
    10 University of California, "Optimization of Ammonia Removal by Ion Exchange Using Clinop-
tilolite," U.S. Environmental Protection Agency Water Pollution Control Research Series No. 17080
DAR 09/71, Sept. 1971.
    11Battelle Northwest and South Tahoe Public Utility District, "Wastewater Ammonia Removal
by Ion Exchange," U.S. Environmental Protection Agency Water Pollution Control Research Series
No. 17010 ECZ 02/71, Feb. 1971.
    12R. Prettyman et al., "Ammonia  Removal by Ion Exchange and Electrolytic  Regeneration,"
unpublished report, CH2M/HILL Engineers, Dec. 1973.
    13"Physical/Chemical Plant Treats Sewage Near the Twin Cities," Water Sewage Works, 120,
86, Sept. 1973.
    14D. Larkman, "Physical/Chemical Treatment," Chem. Eng., Deskbook Issue, 87, June 18, 1973.
    15T. A. Pressley et al., "Ammonia Removal by Breakpoint Chlorination," Environ. Sci.  Technol.,
6, No. 7, 622, July 1972.
    16W. N. Stasuik, L. J. Hetling, and W. W.  Shuster, "Removal of Ammonia Nitrogen by Break-
point Chlorination Using an Activated Carbon Catalyst," New York State Department of Environ-
mental Conservation Tech. Paper No. 26, Apr. 1973.
    17A. W. Lawrence et al., "Ammonia Nitrogen Removal from Wastewater Effluents by Chlorina-
tion," presented at 4th Mid-Atlanta Industrial Waste Conference, University of Delaware, Nov. 1970.
    18P. F. Atkins, Jr., D. A. Scherger, and R. A. Barnes, "Ammonia Removal in a Physical Chemical
Wastewater Treatment Plant," presented at 27th Purdue Industrial Waste Conference, May 1972.
    19R. C. Bauer and V. L. Snoeyink, "Reactions of Chloramines with Active Carbon," J.  Water
Pollut. Cont. Fed., 45, 2990, Nov. 1973.
    20L. R. J. Van Vuuren et al., "Stander Water Reclamation Plant: Chlorination Unit Process,"
Project Rep. 21, Pretoria, South Africa, Nov.  1972.
    21D. F. Bishop et al., "Computer Control of Physical Chemical Wastewater Treatment," Pollu-
tion Engineering and Scientific Solutions, vol. 2, Plenum Press,  1973.
                                           268

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   22G. M. Wesner, "Water Factory 21—Waste Water Reclamation and Sea Water Barrier Facilities,"
Orange County Water District Rep., Feb. 1973.
   23Bechtel, Inc., "A Guide to Selection of Cost Effective Wastewater Treatment Systems," draft
rep. for EPA U.S. Environmental Protection Agency, May 1973.
   24R. Smith, "Updated Cost of Dispersed Floe Nitrification and Denitrification for Removal of
Nitrogen From Wastewater," U.S. Environmental Protection Agency Memorandum, Cincinnati,
Ohio, Apr. 13,1973.
                                          269

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     SLUDGES GENERATED IN PHOSPHATE REMOVAL PROCESSES
               DR. JOSEPH B. FARRELL, CHIEF
                 ULTIMATE DISPOSAL SECTION
           TREATMENT PROCESS DEVELOPMENT BRANCH
       ADVANCED WASTE TREATMENT RESEARCH LABORATORY
          NATIONAL ENVIRONMENTAL RESEARCH CENTER
             ENVIRONMENTAL PROTECTION AGENCY
                     CINCINNATI, OHIO
                       PRESENTED AT

THIRD U.S./JAPAN CONFERENCE ON SEWAGE TREATMENT TECHNOLOGY
                       TOKYO, JAPAN


                      FEBRUARY 1974
                             270

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                      SLUDGES GFTVRATED IN PgQSFHAIE

                             FJE-fOVAL PROCESSES*



     Aluminum and iron salts and lime have been used in the physical-

chemical treatment of uastewater to remove phosphate.  Use of these

chemicals increases the mass of sludge and affects its dewatering

properties.

Quantity

     Isgird,^ ' in discussing Swedish experience, has presented a table

vhich relates sludge production to chemical dose (Table l).  It is

believed that he was referring to experience with tertiary treatment.

The quantities of alum and iron sludges are easily calculated from the

chemical equations showing the reactions of Al^+ and Fe3+ (see Table 2).

The dose of Al or Fe used is related to the phosphorus level in the vaste-

water.  It usually ranges from 1.8 to 2.2 atoms per atom of P.  Isgird's

figures are seen to be quite reasonable.

     When aluminum and iron salts are added at the primary clarification

stage, much more primary sludge is produced than predicted by the chemical

equations.  The reason is the substantial increase in the efficiency of

the clarifier.  Tables 3 and 4 show the anticipated increase in sludge

mass when Al and Fe are added at various points in the wastewater treatment

process.

     The illustration in Table 3 compares sludge production when Al and Fe

are added to the primary clarifier with sludge production when they are
 *  Presented at the Third U.S./Japan Conference on Sewage Treatment Technology,
   Tokyo, Japan, February 14, 1974.
                                      271

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added to the aerator.  Less sludge is produced when the chemicals  are  added




to the aerator.  This is true "because the BOO load on the aerator  is much




reduced when the chemicals are added to the primary.  Since the EOD load



is reduced, there is much less conversion of organic material to carbon




dioxide; consequently total mass of sludge is higher.



     The mass of sludge formed vrhen lime is added to wastewater can also be



calculated from the chemical equations (see Table 5).  It is necessary to



know the chemical analysis of the water before treatment and estimate it



after treatment.  The major difference in calculation method is that the




initial dose of Ca(CH)2 is estimated from the alkalinity of the vastewater



rather than from a relationship between the phosphorus level in the waste-




water and the Ca(OH)2 dose.  Figure 2 shows a correlation of lime dose



with alkalinity of the wastewater.



Dewaterin.'; Properties



     There are a few generalizations that can be made about the sludges




generated by Al, Fe, and Ca(OH)2 addition.  Aluminum and iron salts



generally reduce the solids content of the primary clarifier sludge.



Sludges cannot be thickened to as high a solids content.  The effect is



often unnoticed at lower doses, but when the ratio of metal dose to waste-



vater suspended solids increases, the effect is substantial.  For example,



if enough Al or Fe is added to a typical United States wastewater to remove



90 percent of the phosphate, the sludge thickening and dewatering properties



will be noticeably poorer.
                                    272

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     With liir.3, the effect is the opposite.  Lice improves thickening and



devatcring properties substantially.  It is often possible to eliminate



sludge conditioning agents.  Mass of sludge is generally much higher but



volucs is often lower than if Al or Fs salts were used.



     Table 6 attempts to express theoe qualitative statements in a semi-



quantitative way.  It should only be xised as an approximate guideline for



anticipated results.



Examples
     Barrie.  Tests were reported by Ian Grayx ' of the Ontario Ministry



of the Environment (Canada).  The plant conditions are as follows:



                          3.0 MGD (11, 1KX> m3/da)



                          bar screens, grit removal



                          primary clarifier



                          activated sludge



                          final clarifier



                          two stage digestion



                          waste activated sludge recycled to plant inlet



Alum addition to the primary was compared to alum addition to the aerator.



     A high dose of alum (200 mg/1 of alum, equivalent to 200 x 0.091 =



18.2 E3/1 Al) significantly lowered sludge solids.



     If alum dose was less than 150 mg/1 of alum, there was no effect on



sludge density.



     The point of alum addition (to the primary or to the aerator) did not



affect sludge density.
                                    273

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     Littlo Paver.  This is a email primary plant (15,000 m^/da) in the




city of Windsor, Ontario. ^'  Data are surtaarized in Table 7«  Alum and




lime addition are compared to each other and to a control period (the



previous year).  Altai addition caused a slight reduction in filter yield



and cost of conditioning chemicals increased.  Lime caused a substantial




increase in sludge concentration and filter yield, and reduced chemical




conditioning costs.



     Blue Plains.  This is the principal plant in Washington, D. C.



Table 8 describes the processing sequence at this plant.  During a



lengthy test period, J]Q mg/1 of alum (9.1$ Al) was added to the aerators.



Effects are summarized below:



          A.  Thickening.  Sludge is 7.5$.  Ho change.



          B.  Digestion.  Sludge leaves at 3«5$«  No change.  Ho



              interference with digestion.



          C.  Elutriation.  Higher polymer dose is needed to retain



              fines.  Cost is $7/dry ton vs. $3/dry ton.



          D.  Filtration.  Filter yield is about the same, but solids



              content of cake is 20% vs.  23%. Chemical cost is



              $7/dry ton, slightly over $l/dry ton higher than previously.



     Contra Costa, California.  This system utilizes chemical treatment in



the primary clarifier for phosphorus removal, followed first by carbonaceous



removal and nitrification in a single aeration stage, and finally by




denitrification.^ '  Lime will be used to pH 11 with 14 mg/1 ferric



chloride.  The lime addition reduces the biological load to the second




stage, allowing longer sludge age needed for nitrification.  It also



provides heavy metals removal, and offsets the acid formed in nitrification.
                                    274

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     Waste biological solids are returned to the primary clarifier.



Solids in the primary clarifier underflow are 5-9 percent.  Sludge is



first centrifugcd in a solid bowl centrifuge without polymer.  The



cake contains most of the calcium carbonate, and the centrate contains



most of the calcium phosphate, magnesium hydroxide, and organic



material.  The ceatrate is once again centrifuged using a higher rota-



tional speed and polymer.  The first cake can be calcined to produce



reusable lime.  The cake from the centrate is incinerated for disposal.



     Salt Lake City.  Addition of Al, Fe, and Ca(OH)2 have been investigated



on a large pilot plant scale by the Eimco Corporation at Salt Lake City,



Utah.^'  Results are summarized in Tables 9 and 10.  Results for the Al



and Fe cases are based on a very limited amount of data.



     Results indicate excellent sludge characteristics with line.  Results



with Al and Fe are poor, primarily because the experimenters could not



thicken the sludge.  This work has continued.  Much more information has



been collected but is not yet available.  A modification in the design



of the clarifier has allowed the Al and Fe sludges to settle to higher



solids, giving better filter yields.
                                    275

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                               LITERATURE CITED


(1) Isgird,  Erik,  "Chemical Methods in Present Swedish Sewage Purification
    Techniques," presented at the 7th Effluent and Water Treatment Exhibition
    and Convention,  London,  June 25f  1971*

(2) Gray,  IEJI M.,  "Phosphorus Removal at Earrie WPCP," Ontario Ministry of
    the Environment,  Dec.  1972.

(3) Buratto, D.  A.,  and L.  S. Romano,  "Phosphorus Removal at City of Windsor's
    Little River Plant," in Proc.  of  Tech. Seminar on Physical-Chemical
    Treatment, Mar.  9>  1972,  Ontario  Ministry of the Environment.

(4) Parker,  D. S., F. J. Zadick,  and  K.  E. Train,  "Sludge Processing for
    Confined Physical-Chemical-Biological Sludges," Environmental Protection
    Technology Series,  EPA-R2-73-250,  July 1973.

(5) Burns, D.  E., and G. L.  Shell,  "Physical-Chemical Treatment of a
    Municipal Wastewater Using Powdered Carbon,"  Environmental Protection
    Technology Series,  EPA-R2-73-264,  Aug. 1973.
                                     276

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    TABLE 1 — SLUDGE PRODUCED
       BY CHEMICAL ADDITION


ALUM  :   ADD 4 x mg/1 of Al
FERRIC:   ADD 2.5 x mg/1 of Fe
LIME  :   ADD 1 to 1.5 mg/1 of Ca(OH)2

(AFTER E. ISGARD - SWEDISH EXPERIENCE)
     9  — Al and Fe SLUDGE PRODUCTION
         Al + PO^   =
         1 kg          4.52 kg
         Al + 30H   =  Al(OH)3
         1 kg          2.89 kg
         Fe + PO.   =  FePO^
         1 kg          2.70 kg
         Fe + 3QH   =  Fe(OH)
         1 kg          1.91 kg
                 277

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        Table 3 :  Calculated Sludge Mass  (ib/M.G.)
                         Fe to    Fe to    Al  to   Al to TF
          Conventional  Primary  Aerator  Aerator  Clarifier
Primary
  SS"Removal
  Sludge Solids
  Fe Solids
  Al Solids
  Total

Activated Sludge
  Secondary Solids
  Fe Solids
  Al Solids

Trickling Filter
  Secondary Solids
  Al Solids

Totals
             1250
                0
                0
             1250
 715



(656)


1965
                         536
                804
                541
  75^
1875     1250     1250
 605

2480     1250     1250
                   8o4

                   425
                                  1250

                                  1250
                        3016
               2595
                  2479
 745
 483

2478
  Table  k   Basis for Sludge Mass Calculation
                      in Table 3
Cation/P Dose
 (n:ol/rnol)

    1.5

    1.75
     lb Chemical Sludge/lb Cation
     Ib/Ib AlIb/lb Fe"
        3.9

        3.8
                    2.4

                    2.3
Assumptions:
  Cation/P Dose
  Cation/P Dose
1.5 nol/Eiol to aerator
1.75 Riol/mol to primary or before
  Trickling Filter clarifier
  Influent Sevage
            BOD = 230 mg/1
             SS - 300 iag/1
              P =  10 mg/1
                      278

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    TABLE 5 — REACTION OF LIMB WITH WASTEWATER
5Ca(OH)2




Ca(OH)2




      Mg
HCOo
   *J
              Ca(OH)
            CaC03  +
                  20H   =  Mg(OH),
         =  Ca  +  20H
                                           90H
                                          + OH
    TABLE 6 — FZLTRABILIIY OF PHOSPHATE SLUDGES
CEEMCAL
    3+
  A1
  LIME
     PRIMARY

 YIELD      COST*



0.5-0.8   MJCH MORE



0.5-0.8   14UCH MORE




1.1-1.5   LESS
                                     PRBIARY + WAS

                                                COST*
                       YTET.D        	



                      0.7-1.0     MORE



                      0.7-1.0     MORE



                      1.3-1.8     MUCH LESS
       * COST OF CONDITIONING CHEMICAL
                           279

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     TAELE_T — LITTLE RIVER WPCP. WINDSOR,
PRIMARY PLAINT (15,000 m3/da.)

DOSE (ns/1)
SLUDGE (mg/1)
SLUDGE CONCW.(#)
FILTER YIELD
CONTROL
0
158
6.2
25
ALUM
150
310
5.8
23
LIME
125-150
338
11.1
35
       THKG COST-*
($/metric ton)
IT.TO
19.60
13.00
     Fed-,  and LIME
TABLE 8  — BLUE HAJTS WFCP, WASHINGTON, D.C.


      CAPACITY     300 MGD (1,130 x

      KWCESS      PRIMARY CLARIFICAHOW
                   HIGH-RAIE ACnVATJED SLUDGE

      SLUDGE PROCESSDTg

       A.   PRB-IARY IS MIXED WITH V7ASTE A.S.
            and THICKENED
       B.   DIGESTION
       C.   TWO-ST^.GE ELUTRIATION
       D.   FILTRATION (POLH-ER  + Fed,)
                        280

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      TABLE 9 — SALT LAKE CITY PILOT PLAHT,




                       PRIMARY DULY
DOSE (rag/1)




SLUDGE (mg/1)



SLUDGE CONC1T.($)




GRAVITY
  SOLIDS LOADHIG (kg/m2-da)




  UNDERFLOW SOLIDS
FeClg    ALUM     Ca(OH)2




 120      150       460



 168      144       840



   1.3      0.3      12.0
  r4       24       210



   3.0      1.5      20.0
     TABLE  10  —  SALT LAIS  CITT PILOT PLAKT.
PRIMARY GllLY
DOSE (ma/1)
VACUUM FILTRATION
Ca(03)2 DOSE (kg/kg)
YIELD (kg/m2-hr)
CAKE SOLIDS (<)
FeClg
120
0.2
5-9
20
ALUM
150
0.2
3.9
20
Ca(OH)2
460
0
49
4o
                            281

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ro
oo
ro
u_
       12
    DC
    LU  11
    LLJ

    co  10
        7
1 III II
^**&~°
a SX^
n X*v A ^
s A
0
y^ SYMBOL ALKALINITY
/A (mg/I)
y^ A 100-125
/ o 226
^ a 440-460
X
X
^x 0 277
^ 450
* 300
1 III IS
- - -




REF

1.
2.
3.

4.
5.
5.

— —

—

i
. LOCATION

WASH., D.C.
S. TAHOE, CA.
NINE SPRINGS.
Wl
LEBANON, OH
LEBANON, OH
BATAVIA, OH-

               0.3
                     0.5
3.0
                      0.7    1.0           2.0

                         CaO/ALKALINITY
FIG. 2:  RATIO OF LIME DOSE (mg/I) TO INITIAL WASTEWATER
                        ALKALINITY (mg/I)

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                 EPA EXPERIENCES IN OXYGEN-ACTIVATED SLUDGE
                           EDWIN F. EARTH, CHIEF*
                        BIOLOGICAL TREATMENT SECTION
                    TREATMENT PROCESS DEVELOPMENT BRANCH
               ADVANCED WASTE TREATMENT RESEARCH LABORATORY
                  NATIONAL ENVIRONMENTAL RESEARCH CENTER
                             CINCINNATI, OHIO
                              PRESENTED AT

      THIRD U.S./JAPAN CONFERENCE ON SEWAGE TREATMENT TECHNOLOGY
                              TOKYO, JAPAN

                             FEBRUARY  1974

'The presentation was based on material prepared by  Richard  C. Brenner  for the
 U.S. Environmental Protection Agency - Technology Transfer  Design  Seminar Program
                                      283

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            EPA EXPERIENCES  IN  OXYGEN-ACTIVATED  SLUDGE

                          Richard C. Brenner

                             INTRODUCTION
     Utilization of oxygen aeration for activated sludge treatment  is
receiving increasing attention in wastewater treatment plant construction
in the United States.  The concept, although more than 20 years old, has
received serious consideration only during the  last  six years with the
development of several cost-effective systems for dissolving and utilizing
oxygen gas in an aeration tank environment.
     The rapid transition from the drawing boards to full-scale imple-
mentation has been possible because of intensive government and private
research and development programs.,  The U.S. Environmental Protection
Agency (EPA) and its predecessor organizations  have contributed signi-
ficantly to the total research and development  effort.  The purpose of
this paper is to summarize the role of EPA during the period of 1968-1974
as the oxygen aeration process  progressed to its current level of development.
     As outlined in Table 1, EPA has pursued seven active projects  to date.
The projects include in-house pilot plant studies to examine process
kinetics, extramural feasibility grants and contracts, extramural materials
and safety projects, and extramural demonstration grants.
     The EPA contribution to the projects described in Table 1 exceeded
 $3.4 million through Fiscal  Year  1974  (ended June 30,  1974).
The cost breakdown by project is given in Table 2.
     Test facilities, experimental plans, and results (where available)
for each of the above projects are summarized in the following sections.
                          THE BATAVIA PROJECTS
     A research and development contract was awarded to the Union Carbide
Corporation in October  1968  to evaluate a proprietary staged, covered-
tank oxygenation system at the Batavia, New York, Water Pollution Control
Plant.  Union Carbide was awarded a follow-up contract in June 1970 to
                                    284

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                TABLE 1.   EPA RESEARCH AND DEVELOPMENT
                          PROJECTS ON OXYGEN AERATION
  Project
Objective
1.    Batavia 1 and II
     (Union Carbide Corporation)
2.    Newtown Creek
     (New York City)

3.    Las Virgenes (California)
     Municipal Water District

4.    FMC Corporation


5.    EPA/District of Columbia
     (Blue Plains) Pilot Plant
6.    Bureau of Reclamation
7.   Rocketdyne Division  of
     Rockwell International
Establish feasibility of multi-stage,
covered-tank oxygenation concept.

Scaled-up demonstration of multi-stage,
covered-tank oxygenation system.

Demonstration of single-stage, covered-
tank oxygenation system.
Establish feasibility of open-tank
oxygenation concept.

Determine process kinetics over wide
range of operating conditions.
Materials of construction corrosion
testing.

Define safety  requirements and
develop safety manual and checklist.
          TABLE 2.  EPA RESEARCH AND DEVELOPMENT EXPENDITURES
                         ON OXYGEN AERATION THROUGH FY-73
  Project
             Cost to EPA  Type of Project
Union Carbide Corporation (Batavia I and II)     $  795,000

New York  City (Newtown Creek)                   $1,574,000

Las Virgenes (California) Municipal Water        $  186,000
District

FMC Corporation                                  $  142,000

EPA/District of Columbia (Blue Plains)           $  500,000
Pilot Plant

Bureau of Reclamation                            $  165,000

Rocketdyne Division of Rockwell International    $   92,000
                                        TOTAL    $3,454,000
                            Contracts

                            Grant

                            Grant


                            Grant

                            Contracts and
                            Inhouse

                            Contract

                            Contract
                                    285

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better define soluble organic removals and excess biological sludge  pro-
duction and to undertake initial pilot plant studies on oxygen  sludge
dewatering and stabilization.  The oxygenation system was installed  in
one of two existing air-activated sludge trains at Batavia.  During  the
first contract, the performance of the oxygen train was evaluated against
that of the intact air train.  A schematic diagram of the Batavia Plant
after installation of the oxygen system is shown in Figure 1.
     The oxygen system configuration evaluated at Batavia was the first
large-scale embodiment of the now well known "UNOX" process.*   A typical
three-stage "UNOX" aerator is shown schematically in Figure 2.  The  aerator
operates as a series of completely mixed stages, thereby approximating plug
flow.  Oxygen gas is fed under the aeration tank cover at the inlet  end of
the tank only and flows co-currently with the liquid stream from stage to
stage.  Gas is recirculated in each stage by centrifugal compressors which
force the gas down hollow shafts out through submerged rotating spargers.
Submerged turbines maintain suspension of the mixed liquor solids and
disperse the oxygen gas.  A mixture of unused oxygen gas, cell  respiration
by-product carbon dioxide, and inert gases is exhausted from the final stage,
typically at an oxygen composition of about 50% and a flow rate equal to
10-20% of the incoming gas flow rate.  Using co-current gas and liquid flow
to match the decreasing dissolution driving force inherent in continually
decreasing oxygen gas composition with the decreasing oxygen demand of
wastewater undergoing biological treatment has proven to be a very efficient
oxygen contacting and utilization technique.
     A second-generation multi-stage process has been developed and utilized
both by Union Carbide and Air Products and Chemicals, Inc.  This adaptation of
the original covered-tank concept replaces the recirculating compressors and
rotating spargers with surface aerators.   Oxygen transfer is accomplished by
gas entrainment and dissolution.  Submerged turbines are 'also used optionally
where tank geometry requires additional mixing capability.  As  shown in Figure 3,
all other aspects of the system are unchanged.  The first Air Products and
Chemicals version of the covered-tank, surface-aerator concept has been oper-
ating for approximately three yearsat tne Westgate Treatment Plant in Fairfax
County,  Virginia (design flow 12 mgd).   Operation commenced in July 1972
^Mention of a trade name or commercial products does not constitute Environ-
 mental Protection Agency endorsement or recommendation for use.
                                     286

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                                                                                                       PLANT
                                                                                                      ,,EFFLUENT
IV)
oo
                                                                                                            CHLORINE
                                                                                                            CONTACT
                                                                                                            TANKS
                                                                                                                             02
                                                                                                                             STORAGE
                              KEY

                               SEWAGE FLOW

                               SLUDGE FLOW
                               DESIGN  POPULATION  25,000

                               &VG FLOW 2.5 MIL GAL /DAY
                               MAX.FLOW 6.25 MIL GAL /DAY
MAIN PUMP STATION
                  FIGURE  1.   SCHEMATIC  FLOW DIAGRAM  FOR WATER POLLUTION  CONTROL PLANT,  CITY OF  BATAV1A,  NEW YORK

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IN3
00
00
                                  AERATION
                                  TANK COVER
                                  OXYGEN
                                 PEED GAS
                                  WASTE
                                  LIQUOR
                                  FEED
                                RECYCLE
                                SLUDGE"
                                                      PROPELLER
                                                      DRIVE
GAS RECIRCULATION
COMPRESSORS
                   EXHAUST
                  "GAS
                 MIXED LIQUOR
                 "EFFLUENT TO
                 CLARIFIER
                                                                                              PROPELLER
                                                                                              SPARGER
                          FIGURE  2.   SCHEMATIC DIAGRAM OF MULTI-STAGE, COVERED-TANK OXYGENATION
                                      SYSTEM WITH GAS RECIRCULATION COMPRESSORS AND SUBMERGED
                                      TURBINE/SPARGERS

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                       AERATION TANK COVER
                                                                SURFACE AERATOR
ro
oo
                    OXYGEN
                   FEED GAS
            WASTEWATER
                     FEED
RECYCLE
SLUDGE
                                                                MIXER DRIVE
                                                                          EXHAUST
                                                                          GAS
                                                                          MIXED LIQUOR
                                                                          EFFLUENT TO
                                                                          CLARIFIER
                                              SUBMERGED PROPELLER  (OPTIONAI)
               FIGURE 3.  SCHEMATIC DIAGRAM OF MULTI-STAGE, COVERED-TANK OXYGENATION SYSTEM
                         WITH SURFACE AERATORS

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at Speedway, Indiana, the first municipal plant to utilize the Union
Carbide surface aerator system (design flow 7.5 mgd).  The surface aerator
modification of the basic multi-stage process has exhibited better cost
effectiveness for tanks up to approximately 15 feet deep and is being used
increasingly in full-scale design.  Market forecasts and actual experience
to date of firms selling multi-stage, covered tank oxygen systems indicate
that 80-85% of the plants that eventually utilize this oxygen system concept
will employ surface aerator designs.  A report currently being prepared for
EPA by Air Products and Chemicals documenting the Fairfax County, Virginia
case history from inception through two years of operation with the oxygen
system will be available by mid-1975.
     The results of the Batavia projects have been widely disseminated in
two EPA Water Pollution Control Research Series Reports (17050 DNW 05/70)
(17050 DNW 02/72).  One of the conclusions expressed in these reports is
that oxygen aeration can provide equal treatment efficiency to air aeration
with only one-third as much aeration volume.  This conclusion has been sub-
ject to widespread criticism.  In that this generalization was reached by
comparing an efficient oxygen contacting system with a relatively inefficient
coarse-bubble air aeration system, the criticism appears to be justified.
The increasing variety of air aeration equipment being marketed offers a
wide range of oxygen transfer kinetics.  Some of this equipment has been
shown to  be capable of supporting the higher mixed liquor solids concen-
trations necessary for justifying smaller volume biological reactors (e.g.,
the INKA aeration system, Divet,  et al., 1963).  Design engineers are urged
to investigate and prepare cost estimates for both air and oxygen systems
as a basis for process selection.  Process selection should  be made from a
total integrated system comparison, including aeration, secondary clarifi-
cation, and excess biological sludge handling and disposal requirements.
     Pertinent results of  the two Batavia projects relating only to oxygen
system performance are summarized below:
     1.   The feasibility of achieving high oxygen  gas utilization (91-95%)
          was established.
     2.   Efficient biological performance (90-95% BOD^ and suspended solids
          removals, 80-85% COD removal) was demonstrated with short aerator
          detention periods (1.4-2.8 hours based on Q) and high organic
          volumetric loadings (140-230 Ib BOD5/day/l,000 ft3).
                                   290

-------
     3.   High mixed liquor dissolved oxygen (D.O.) levels (8-12 mg/1)  were
         maintained at high mixed liquor suspended solids (MLSS) concentration
         (3,500-7000 mg/1).
     4.   Warm weather secondary clarifier performance deteriorated above
                                                   2
         an average surface loading of 1,600 gpd/ft .
     5.   Oxygen sludge exhibited excellent thickening properties during
         secondary clarification (settled sludge of 1.5-3.0% solids).
     6.   Aerobic digestion of oxygen waste activated sludge with oxygen
         produced comparable volatile suspended solids (VSS) reduction
         rates to those given in the literature for air aerobic digestion
         processes.  Reductions in oxygen sludge VSS concentrations of 25
         and 40% were achieved with 7 and 15 days of aerobic stabilization,
         respectively.
     7.   Direct vacuum filtration of undigested oxygen waste activated
         sludge was shown to be feasible using 10% ferric chloride for
                                                       2
         conditioning.  Cake yields of 3.5-4.5 Ib/hr/ft  and moisture
         contents of 83-85% were achieved at a cycle time of 2.4 min/rev.
         Moisture content improved to 75-80% but cake yield dropped to
                         2
         1.5-2o5 Ib/hr/ft  at a cycle time of 6.3 min/rev.
     8.   Vacuum filtration of aerobically digested oxygen waste activated
         sludge proved to be infeasible with the chemical conditioners
         tested.
                      THE NEWTOWN CREEK PROJECT
     Results of the initial Batavia contract were judged sufficiently
encouraging to justify a scaled-up demonstration of the multi-stage oxygen
system in a large municipal plant.  A research and development grant was
awarded  to New York City in June 1970 to convert one of sixteen parallel
bays at  its Newtown Creek facility to oxygen using the recirculating com-
pressor/submerged turbine version of the "UNOX" process.  The design flow
of the test bay is 20 mgd, roughly 10 times higher than the capacity of the
Batavia  oxygen system.  In addition to the $1.574 million EPA grant, New York
City   provided   over $1.2 million in city funds in support of the project.
     The Newtown Creek plant was designed on the modified aeration principle
for 1.5  hours of aeration time (based on Q) and treatment efficiencies in
the range of 65-70%.   The city is now confronted with an upgrading problem
in a land-locked neighborhood (see Figure 4), a situation common to many
                                    291

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N

     CK
     l/l
                                 z
                                 <
                                 u
                STREET
                      /////A
                                     1 SLUDGE

                                     DIGESTION
           OXYGEN AERATION

               TEST BAY 	
        o   o
      )O   O
    p°   °
   po   o
	A If    
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large  urban plants in the United States.  Oxygen was believed to be a good
candidate  for achieving the required 90% BODj. removal within the confines
of the existing aeration tanks and secondary clarifiers.  Future conversion
of the entire 310 mgd facility to oxygen  was the ultimate objective provided
a removal  up to the 90% ± 8005 level could be consistently demonstrated in the
 test  hay.  Two views of  the Newtown Creek test bay are jshown in Figure 5.
     The test bay went on stream in early June 1972.    Extensive mechanical
problems and unreliable meters prevented accurate data collection during
the start-up phase (June 4, 1972-September 16, 1972) during which time the
influent flow was increased from 11 mgd to the design level of 20 mgd.  Data
for this period are limited to effluent quality as summarized in Table 3.
            TABLE 3.  EFFLUENT QUALITY AT NEWTOWN CREEK
                      DURING START-UP (6/4/72-9/16/72)
Flow
(mgd)
11 _+ 2*
14 ± 3b
20 + 4C
Duration
(weeks)
Effluent Concentration (mg/1)
Total
4 10
5 8
6 15
Soluble Total
BOD COD
4 68
3 55
4 62
Soluble
COD
50
41
47
Suspended
Solids
18
19
18.
     aMLSS = 4,865 mg/1, Detention Time (based on Q) = 2.7 hr  +.
      MLSS = 5,920 mg/1, Detention Time (based on Q) = 2.1 hr  _+.
     CMLSS = 4,260 mg/1, Detention Time (based on Q) = 1.5 hr  +.
     Metering difficulties were finally resolved by mid-September 1972 permitting
commencement of the extensive data collection program planned for this project.
From September 17, 1972 through September 1, 1973, seven phases of a ten-phase
experimental program were completed.  The influent flow conditions for these seven
phases are summarized in Table 4.  Diurnal peak, average, and minimum flow rates
for Phases 4 through 7 are given in Table 5.  With the exception of Phase 7, the
diurnal  fluctuation patterns were selected to simulate the actual influent flow
pattern., o± the Newtown Creek facility.
                                       293

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RAW
SEWAGE
                       FIVE GAS RECIRCULATING
                          COMPRESSORS
                                   EIGHT SUBMERGED
PUMPS
[
RAW 	 	
SEWAGE
ijT
V
'




D D D D D
0
0
o
o
o
o
^
0

X


X' PROPELLER MIXERS
t
55'
I
=

-* 	 Ann1 	 v
SECONDARY
EFFLUENT

                MIXER 	
                ASSEMBLY
          DRIVE
          PROPELLER
          SPARGER
                                           PLAN VIEW
                                            NO  SCALE
           GRIT
        CHAMBER I
FOUR-STAGE OXYGEN  AERATOR
                                                                      SECONDARY
                                                                      EFFLUENT

                                                      SECONDARY
                                                      CLARIFIER

                       SLUDGE
                       RECYCLE
                       ELEVATION
                        NO SCALE
                                                                   SLUDGE
                                                                  WASTING
          FIGURE 5.  PLAN AND ELEVATION VIEWS OF OXYGEN AERATION TEST  BAY, NEWTOWN CREEK

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        TABLE 4.   EXPERIMENTAL SCHEDULE FOR NEWTOWN
                    CREEK PROJECT (9/17/72-9/1/73)
Phase
Dates
Influent Flow Condition
           9/17/72   11/25/72
           12/10/72   2/1/73
                  20.8 mgd (Constant)

                  14 	> 20 	>  15 mgd
                  Avg. 17.7 mgd (Winter Upset)
_> t-i JLO/ /j H-/ // /o o 	 7 ^.u mgd
AVG. 15.1 mgd (Winter Restart)
4
5
6
7
4/8/73
6/3/73
7/8/73
8/12/73
6/2/73
- 7/7/73
- 8/11/73
- 9/1/73
20.6 mgd
25.3 mgd
30.0 mgd
35 o 4 mgd
(Diurnal)
(Diurnal)
(Diurnal)
(Diurnal)
         TABLE 5.  DIURNAL FLUCTUATION PATTERNS FOR
                    NEWTOWN CREEK (4/8/73-9/1/73)
Phase
4
5
6
7
Avg. Flow
(mgd)
20.6
25.3
30.0
35.4
Peak Flow
(mgd)
24
30
36
37.5*
Minimum Flow
(mgd)
14
17
19
30
 *Maximum  influent pumping capacity.
                                  295

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     A performance summary for the oxygenation  system  for Phases  1  through
7 is presented in Table 6.   System sludge  characteristics,  aerator
 loadings,  and  secondary clarifier loadings are  summarized  in Tables
7, 8, and  9, respectively.
           TABLE 6.  PERFORMANCE SUMMARY FOR NEWTOWN CREEK
                           (9/17/72-9/1/73)

Total BOD In

(mg/D*
Total BOD Out (mg/1)
% Removed
Soluble BOD
Soluble BOD
% Removed
Total COD In
Total COD Out
% Removed

In (mg/D*
Out (mg/1)

(mg/D*
(mg/1)

1
156
9
94
84
4
95
356
61
83
2
157
21
87
78
13
83
365
88
76
3
152
17
89
91
12
87
365
76
79
Phase
4
171
17
90
102
11
89
365
77
79
5
213
22
90
113
13
88
307
70
77
6
218
21
90
99
11
89
290
64
78
7
212
23
89
88
15
83
308
62
80
Soluble COD Out (mg/1)      50    69    63    69    58    49    46

Susp. Solids In (mg/D*    149   146   144   159   147   125   131
Susp. Solids Out (mg/1)     12    22    17    18    24    17    17
7o Removed                   92    85    88    89    84    86    87
Sewage Temp. Range (°F)     7.7    64    51    53    62    71    72
                            ^    ty     ^     +     +    ^     4,
                            56    53    61    69    74    77    78
*No primary sedimentation.   Concentrations shown are for raw sewage
 influent to oxygen aerator.
                                    296

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     TABLE  7.   AVERAGE  SYSTEM SLUDGE  CHARACTERISTICS
                  FOR  NEWTOWN  CREEK  (9/17/72-9/1/73)
Phase


1
2
3
4
5
6
7
MLSS
(mg/1)

4,890
5,060
4,000
3,875
4,550
4,155
3,090
MLVSS
(mg/1)

4,110
4,150
3,200
3,110
3,640
3,340
2,485
Return
Sludge
Flow
(% of Q)
30
40
50
45
44
34
25
Return
Sludge
TSS
(mg/1)
16,260
12,835
11,370
13,420
15,975
16,330
12,685
SVI
(ml/gram)

45
59
77
53
42
43
48
SRT
(days)

_#
-•$:-
_#
1.35
1.37
1.24
0.77
^Sludge  wasting data not  reliable.
           TABLE 8.   AVERAGE AERATOR LOADINGS  FOR
                    NEWTOWN CREEK (9/17/72-9/1/73)
Phase
1
2
3
4
5
6
7
Detention Time
-Based on Q-
(hr)
1.43
1.68
1.96
1.44
1.17
0.99
0.84
F/M Loading
/lb BODs/day\
Y lb MLVSS /
0.65
0.57
0.57
0.92
1.19
1.62
2.44
Volumetric Organic
Loading
/lb BOD5/day\
\^ 1,000 ft^ )
163
140
110
178
272
331
379
                                  297

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       TABLE 9.  AVERAGE SECONDARY CLARIFIER LOADINGS
                  FOR NEWTOWN CREEK (9/17/72-9/1/73)
Phase
]
2
3
4
5
6
7
Surface Overflow
Rate
(gpd/ft2)
945
805
686
936
1,150
1,364
1,609
Mass Loading
Ab TSS/ft2\
\ day )
50.1
48.2
32.6
43.7
63.0
63.3
52.0
Weir
Loading
(gpd/ lineal ft)
129,000
110,000
93,000
127,000
157,000
186,000
219,000
     From the beginning of the project, New York City officials
considered performance of the oxygen test bay during cold weather the
most critical segment of the experimental program.  It was during the
prolonged severe weather period that the true upgrading potential of
oxygen for Newtown Creek would be most evident.  A discussion of the
data collected through September 1, 1973 at Newtown Creek is first pre-
faced, therefore, with a summary description of the operational difficulties
encountered during the 1972-73 winter season.
     During Phase 1 (autumn 1972),  operation went smoothly and perfor-
mance was obviously excellent.  On November 25, 1972, the test bay was
shut down temporarily to replace a bearing on the sludge recycle pump.
What was planned to be a two-day outage turned into a two-week shutdown
when the stocked spare bearing proved to be the wrong size and a new one
had to be located.  During the outage, sludge in the reactor was continually
oxygenated while the sludge in the secondary clarifier was devoid
of oxygen.  Due to the imminence of the upcoming cold weather, it was
decided to restart the system using the existing sludge rather than empty
the tanks and take the time necessary to generate a new biomass.  The
oxygen test bay was put back into service on December 10, 1972.
                                  298

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    For  the  first  several weeks of Phase 2, performance was satisfactory
as the  influent  flow rate was gradually increased to the design level of
20 mgd.   Shortly thereafter sludge settling properties began to deteriorate
and effluent  BOD ,  COD,  and suspended solids residuals exhibited a slowly
increasing  trend.   Microscopic examination of the mixed liquor revealed
the appearance of  filamentous organisms of both apparent bacterial and
fungus  origin.  Influent flow was then decreased in several increments
during  the  month of January 1973 in an attempt to starve or "burn out" the
filamentous culture or cultures and reestablish a "healthy" population.
     Instead  of  eradicating the filamentous organisms, reduction of flow
and organic loading seemed to have the opposite effect of stimulating
proliferation.  This proliferation was accompanied by the usual indicators
of a bulking  sludge, i.e., a substantial increase in SVI, a rising sludge
blanket in  the secondary clarifier, increasing suspended solids carry-over
in the  final  effluent, and operational difficulty in managing total system
sludge  inventory.
     In trying to determine the source of the filamentous intrusion, it was
postulated  that  the bacterial species (Sphaerotilus) may have developed in
the secondary clarifier sludge blanket during the aforementioned shutdown.
A  local pharmaceutical firm is known to discharge mycelia into the Newtown
Creek sewer system and this was suspected as the source of the fungus
organisms.,   By the end of January 1973, with the influent flow reduced to
15 mgd, the SVI  had risen from a summer background level of 45-50 to 85-100,
effluent suspended solids were exceeding 30 mg/1, effluent soluble BOD  had
increased to over 20 mg/1, and the clarifier sludge blanket was continuing
to rise.  At this point a decision was made to "dump" the entire sludge
inventory,  hose  all settled sludge pockets out of the reactor and clarifier,
and start over.   This second shutdown began on February 1, 1973.
     After  taking some additional time to make repairs to the sludge collection
mechanism while  the clarifier was dewatered, Phase 3 commenced on February  18,
1973.   Conservative loading rates were utilized initially based on the premise
that the best chance to prevent a reoccurrence of the filamentous condition
was a program of gradual and modest increases in F/M loading until the 20 mgd
design  flow rate was reached.  Relatively high MLSS concentrations of 5,000 mg/lt
                                      299

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were maintained as a further measure to minimize F/M loading.  However,
within several weeks a repeat of the experience encountered in Phase 2
became evident with the initial appearance of filaments in the oxygen
sludge.  This time the organisms were definitely identified as fungus.
One possible reason for explaining the higher 1972-73 winter incidence and
enrichment pattern of these fungus organisms in the Newtown Creek oxygen
sludge as opposed to that facility's air sludges  is the lower mixed
liquor pH inherent to the operation of the covered-tank oxygen system.
     With the prospect of impending project failure a real possibility,
a joint decision (New York City, Union Carbide,  and EPA) was reached to
accept the presence and proliferation of the fungus organisms as a cold
weather phenomenon and attempt to find an operating mode that would permit
satisfactory winter performance at design flow in spite of them.  Accordingly,
a program of increased sludge wasting was initiated which eventually lowered
the MLSS concentration to less than 4,000 mg/1 and the SRT* to slightly
more than one day.  At the same time influent flow was elevated in several
fairly rapid increments to 20 mgd (equivalent to an aerator detention time
of 1.5 hours based on Q).  These steps yielded an F/M at the end of the
phase in the range of 0.75-0.80, considerably higher than the average of
0.57 for all of Phase 3.  The altered operating philosophy proved to be
the correct decision, resulting in a controllable clarifier sludge blanket
and stable cold weather performance at design flow.  Percentage removals
for the remainder of Phase 3, although not as high as Phase 1, were within
satisfactory limits.  As the wastewater temperature increased during early
spring, the concentration of filamentous organisms diminished, and they
eventually disappeared in early May 1973.
     During the summer of 1973,the Newtown Creek oxygen system exhibited
remarkable capability for absorbing high hydraulic and organic loadings
while still producing a high quality secondary effluent.  Four diurnal
phases (Phases 4-7) conducted from April 8, 1973  through September 1, 1973
successively increased the average influent flow from 20.6 to 35.4 mgd.
During Phase 7 the average nominal aerator detention time was only 52 minutes
with corresponding average F/M, volumetric, and clarifier surface loadings of
* Defined as Ib VSS under aeration/Ib VSS wasted in the waste sludge and
  final effluent/day.
                                    300

-------
2.44 Ib BOD5/day/lb MLVSS, 379 Ib BOD5/day/l,000 ft , and 1,609 gpd/ft2,
respectively.   These results confirmed and exceeded the high-rate
loading potential of oxygen-activated sludge first seen at Batavia.
     At this point in the project it was possible to offer the following
interim status remarks:
          !„  The high-rate loading capability (nominal aeration time < one
          hour) of oxygen aeration operating on Newtown Creek wastewater
          during warm weather was conclusively demonstrated.
          2.  Prospects  appeared promising that a modified method of operation
          evaluated in late winter 1972-73 could circumvent the negative
          effects of what may be an indigenous cold weather filamentous
          condition with oxygen at Newtown Creek and permit satisfactory
          performance at a flow rate at least equal to the design level
          of 20 mgd (1.5 hours of nominal aeration time).
          3.  The operational measures employed to effect the improved
          performance in late winter 1972-73, namely high F/M's and low
          SRT's, occurred naturally to an even greater degree during the
          high loading phases of summer 1973.
          4.  The above comments provide a tentative basis for speculating
          that in some cases oxygen aeration may most beneficially be
          employed at ultra high loading rates substantially exceeding any
          which have been approved to date by State agencies.
     Because of the importance attached to winter operation and performance,
the project was extended to the end of April 1974.  The two major questions
which were  to be addressed during the extended period were whether filamentous
organisms (particularly fungus) would again infest the oxygen sludge as
wastewater  temperature dropped and, if so, would the modified method of
winter operation previously  described permit continuous efficient per-
formance with a diurnal loading pattern centered around an average influent
flow rate of 20 mgd.  If the first few months progressed without upset,
the flow rate  was to be increased to 25 mgd and subsequently to 30 mgd
in the last 2-3 months of the winter season.  The reason for holding this
latter option open was that if a year-round loading capability of 30 mgd
                                    301

-------
could be demonstrated, the Newtown Creek Treatment Plant could conceivably
be satisfactorily upgraded by converting only 11 or 12 of the existing  16
bays from air aeration to oxygen aeration.
     Data for the extended operating period (September 1973 through April
1974) are summarized along with the first seven project phases in a paper
entitled "Upgrading New York City Modified Aeration with Pure Oxygen."
This paper was prepared by New York City personnel (Nash, et al.) and
presented at the 47th Annual  Conference of the Water Pollution Control
Federation.  It is recommended that both this Technology Transfer report and
the New York City paper be reviewed in evaluating the Newtown Creek project.
The project will also be extensively documented and analyzed in the final
grant report now being prepared by the City.  It is anticipated this report
will be available for distribution by mid-1975.
     Another aspect of the project is discussed briefly below.  Initially
the performance of the four-bed Pressure Swing Adsorption (PSA) Oxygen
Generator  was less than satisfactory.  During the 1972 summer startup
phase the unit was out of service due to mechanical problems roughly
40 percent of the time.  These problems have since been largely corrected
and the generator now functions with a down-time that varies between
5 and 10 percent.  During the 1972 startup difficulties one of the four
beds inadvertently became "loaded up" with water vapor.  Subsequently, the
maximum achievable output of the unit was 10 tons of  gas per day at
90 percent oxygen purity versus a design output of 16.7 tons of gas per
day at 90 percent oxygen purity.  This necessitated an increase in
consumption of and reliance on the back-up liquid oxygen reservoir during
peak oxygen demand periods.  The simplified three-bed (moving parts decreased
50 percent) PSA unit installed at Speedway, Indiana, has reportedly operated
at design output with high mechanical reliability following its installation
and startup in mid-summer 1972.
                                    302

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                       THE LAS VIRGENES PROJECT
     A single-stage, covered-tank oxygenation system has been designed by
the Cosmodyne Division of Cordon International Corporation.  The system,
given the name "SIMPLOX" and shown schematically in Figure 6, utilizes an
inflated dome-type cover to contain the oxygen-rich atmosphere over  the
aerator.  This concept is intended primarily for upgrading existing  air
activated sludge plants with a minimum capital expenditure by utilizing
conventional air blowers and coarse-bubble air diffusers to recirculate
oxygen gas.  Air blowers used in this  service must be corrosion proofed
and otherwise modified to be compatible with oxygen gas.  Virgin oxygen
gas is introduced to the aerator through a fine-bubble sparger located
on the tank bottom and on the opposite side wall from the conventional air
diffusers.  Power required for oxygen dissolution is greater for the
"SIMPLOX" process than for the multi-stage systems because:  (1) the
equipment used for transferring oxygen is modified air aeration equipment
and not specifically tailored to oxygen gas kinetics and (2) the gas phase
above the mixed liquor is completely mixed and assumes the same oxygen
composition as the exhaust gas stream; thus, the driving force for dissolving
oxygen in wastewater is less than in the lead stages of multi-stage  aerators.
However, capital costs for converting an existing aerator from air to oxygen
service should be significantly less with the "SIMPLOX" approach because
staging baffles and multiple oxygen dissolution equipment assemblies are
not required.  Since the gas phase is completely mixed, exhaust oxygen,
carbon dioxide, and inert gases can be bled from any point of the inflated
dome and any of several activated sludge flow configurations, including plug
flow, complete mix, and step aeration, can be used as desired.
     A research and development  grant  was  awarded  to  the  Las Virgenes (Cali-
fornia)  Municipal  Water District (a suburb of  Los  Angeles)  in June  1971 to
evaluate the "SIMPLOX"  system at its  Tapia Water Reclamation Facility.  The
experimental program concluded on September 10,  1973.   The  District contributed
$62,000  in support of the project,  supplementing the  $186,000 EPA grant.  An
empty nominal one  mgd train was  available  for  the  oxygen  study because of a
recent expansion at the Tapia facility.  The manner  in  which the oxygen system
was incorporated into this existing train  is  shown in plan  view  in  Figure 7.
                                    303

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               r
V





"* ' " ' '" 1
(LIQUID 02
STORAGE

02
APORIZER
                                                      EXHAUST
                                                        GAS
                                           )
r
PURE 02
    FEED
                                             |

                                             1
                                             1
CO
O
  PRIMARY
  EFFLUENT
       1
                            INFLATED DOME

                     GAS PHASE-COMPLETELY MIXED
RECIRCULATING
    COMPRESSOR
                        MODIFIED AERATION TANK

                    02 SPARGER
                   U_LU
           rn   m   U   M   Lf
                                                                           SECONDARY
                                                                           EFFLUENT
                      RECYCLE
                                                                                    WASTE
                                                                                    SLUDGE
           FIGURE 6.  SCHEMATIC DIAGRAM OF DIFFUSED AIR AERATION SYSTEM MODIFIED TO
                    RECIRCULATE OXYGEN GAS,  LAS VIRGENES PROJECT

-------
                              COVERED AERATION TANK
                              118'x30!xl5'  WD
PRIMARY EFFLUENT
STEP FEED

PURE 02
GAS FEED
CO
0
cn
" 1 i


v°
,\
2 SPARGER
AIR DIFFUSERS
?????????
A 6 A 6 
1 	
A A A | A A
i J
j_




/ CIRCULAR \
^/ CLARIFIER \


1 45' DIAxlO' / |
\J»°y \
RECTANGULAR
CLARIFIER
120'x20'xlO' WD
SECONDARY
EFFLUENT
_-^

RECIRCULATING
AIR COMPRESSOR
                              RECYCLE GAS I
          EXHAUST
I	»S GAS
         FIGURE 7.  FLOW DIAGRAM FOR LAS VIRGENES OXYGENAT10N SYSTEM

-------
Tha schedule followed during the experimental program  for  the  project  is
outlined in Table 10.  The range of aerator  loadings examined  was  not  as
broad as at Newtown Creek due to influent flow  limitations and a weaker
aerator feed (primary effluent at Las Virgenes, raw sewage at  Newtown
Creek)„  The experimental program consisted  of  seven phases  characterized
by increasing flow and system loadings.  To  effect a more pronounced
increase in aerator loading, only 45 percent of the available  aerator
volume was utilized in the last five phases.  This was accomplished via
the installation of a temporary bulkhead across the width of the aeration
tank after Phase 2.
      TABLE 10.  EXPERIMENTAL SCHEDULE .FOR LAS VIRGENES
                      PROJECT (4/25/72-9/10/73)
Phase
1
2
3
4
5
6
7
Dates
4/25/72
9/11/72
1/22/73
3/9/73
4/4/73
5/1/73
5/15/73
- 7/31/72
-11/13/72
3/8/73
4/3/73
4/30/73
5/14/73
9/10/73
Influent
Flow
(mgd)
1.0
2.0
1.0
1.13
1.3
1.54
1.85
% of Aerator
In Use
100
100
45
45
45
45
45
No. of
Clarif iers
In Use
1
2
1
2
2
2
2
     System performance for the Las Virgenes project is summarized in
Table 11.  Tables 12, 13, and 14 summarize, respectively, system
sludge characteristics, aerator loadings, and secondary
clarifier loadings.   Project data and information are presented in
more thorough fashion in the final grant report.  This report, currently
being reviewed by EPA, is scheduled to be available for distribution by
the end of the first quarter of 1975
                                   306

-------
           TABLE 11.   PERFORMANCE SUMMARY FOR LAS VIRGENES
                         (4/25/72   9/10/73)

Total BOD5 In (mg/1)*
Total BOD5 Out (mg/1)
% Removed
Total COD In (mg/1)*
Total COD Out (mg/1)
% Removed
Soluble COD In (mg/1)*
Soluble COD Out (mg/1)
% Removed
Susp. Solids In (mg/1)*
Susp. Solids Out (mg/1)
% Removed
1
82
2
97
153
35
77
58
16
72
73
9
88
2
69
4
94
136
35
74
43
19
56
67
7
90
3
79
2
97
170
29
83
76
23
70
39
4
90
Phase
4
107
5
95
218
35
84
93
26
72
53
7
87
5
115
9
92
262
37
86
101
31
69
63
5
92
6
103
9
91
242
40
83
101
31
69
59
4
93
7
95
10
89
238
50
79
100
32
68
44
6
86
Turbidity Out (JTU)       232       3223


NH3-N In (mg/1)*         13.0    6.8   10.7    14.2   15.6   15.8  15.6
NH3-N Out (mg/1)          0.4    0.1    0.2     4.1    4.8    2.8   3.1
% Removed                97     99     98      71     69     82    80


N03-N Out (mg/1)         16.2   15.3    8.8     6.9    5.6    7.5   8.0

^Concentrations shown are for primary effluent feed to oxygen aerator.
                                 307

-------
TABLE 12.  AVERAGE SYSTEM SLUDGE  CHARACTERISTICS
             FOR LAS  VIRGENES  (4/25/72-9/10/73)
Phase MLSS MLVSS
(mg/1) (mg/1)

1 3,700 2,950
2 3,750 3,050
3 3,815 2,950
4 3,570 2,715
5 3,050 2,485
6 2,595 2,170
7 2,535 2,115
TABLE 13. AVERAGE
Return Return
Sludge Sludge
Flow TSS
(% of Q) (mg/1)
30 14,325
30 13,295
32 12,890
32 9,230
40 7,105
39 6,705
40 8,350
AERATOR LOADINGS FOR
SVI SRT
(ml /gram) (days)

99 79
179 68
175 46
200 30
247 12
191 9
117 12

LAS VIRGENES (4/25/72-9/10/73)
Phase Detention Time
-Based on Q-
(hr)
1 9.56
2 4o78
3 4.30
4 3.81
5 3o31
6 2.79
7 2.32
F/M Loading
fib BOD5/day \
\ Ib MLVSS /
0.07
0.11
0.15
0.24
0.33
0.41
0.46
Volumetric Organic
Loading
fib BODs/day^
V 1,000 ft?/
13
22
27
42
52
56
62
                            308

-------
       TABLE 14.  AVERAGE SECONDARY CLARIFIER LOADINGS
                 FOR LAS VIRGENES (4/25/72-9/10/73)
    Phase          Surface Overflow          Mass Loading
                         Rate                /lb TSS/ft2 \

1
2
3
4
5
6
7
(gpd/ft2)
417
501
417
283
326
386
464
V day )
16.7
20.4
17.5
11.1
11.6
11.6
13.7
     A cursory review of Table 11 reveals that effluent quality for the
entire Las  Virgenes  project was superb and surpassed that observed at
Newtown Creek.  This can be attributed to three factors:  (1)  the lower
aerator organic loadings which permitted a high degree of COD  insolubili-
zation, (2) the very conservative secondary clarifier surface  and mass
loadings which promoted highly effective solids capture, and (3)  the lack
of any significant industrial waste contributions.   A major objective of
wastewater  treatment in the Las Virgenes District is the production of an
ultra high  quality  secondary effluent after chlorination suitable for
agricultural reuse.   The thrust of this project, therefore, was geared
not so much to maximizing system loadings (as was the case at  Newtown Creek)
as maintaining truly superb quality effluent and determining the effect of
a relative  conservative progression in system loadings on single-stage
nitrification.  As shown in Table 15, virtually complete nitrification
was observed with F/M loadings between 0.07 and 0.15 lb BOD5/day/lb MLVSS.
For F/M loadings between 0.24 and 0.46 lb BOD /day/lb MLVSS, nitrification
was only 69-82 percent complete.  Lower wastewater temperatures may also
have played a role in the decreased nitrification of the latter four phases.
                                    309

-------
          TABLE 15.  EFFECT OF ORGANIC LOADING AND
               WASTEWATER TEMPERATURE ON NITRIFICATION
                  AT LAS VIRGENES (4/25/72-9/10/73)
Phase
1
2
3
4
5
6
7
F/M
/lb BODs/day\
^ lb MLVSS J
0.07
0.11
0.15
0.24
0.33
0.41
0.46
SRT
(days)
79
68
46
30
12
9
12
Wastewater
Temp . Range
(°F)
70-77
73-79
65-67
65-67
67-70
68-71
70-75
% NH3-N
Removed
97
99
98
71
69
82
80
Fin. Eff.
N03-N
(mg/1)
16.2
15.3
8.8
6.9
5.6
7.5
8.0
     Another major goal of the Las Virgenes staff was to minimize excess
biological sludge production as much as possible.  This goal probably led
to the most significant problem area encountered on the project, a very
evident bulking sludge.  No sludge was intentionally wasted from the
system during Phases 1 and 2.  Wastage of suspended solids in the final
effluent and final clarifier skimmings was sufficient to balance net system
biomass growth at the low F/M loadings employed.  Resulting SRT's were as
high as 79 days and the SVI climbed to a level near 200 ml/gram.  Despite
the instigation of a scheduled wasting program in Phase 3, the sludge
continued to bulk and the SVI climbed even higher.  It was not until Phase 7
at an SRT of 12 days and an F/M loading of 0.46 lb BOD /day/lb MLVSS that a
significant drop in SVI occurred.  The bulking sludge condition is attributed
here to a combination of Sphaerotilus filamentous development due to the
inordinately high SRT's and the accumulation of other poor settling debris
in the floe matrices.  It was only because of the low clarifier loadings
that efficient overall performance was sustained.  Sludge blanket levels
frequently rose to within a few feet of the clarifier weirs.  The Las Vir-
genes experience illustrates the potential operating difficulties that can
and probably will occur at very low oxygen system loading rates.
                                    310

-------
     One definite conclusion reached during the  project  is  that  the inflated
 tent (dome) concept is not suitable for permanent  installation.   New leaks
 developed repeatedly in the polyvinyl material due to  separation of the
 tent/tank interface, abrasion against the  tent support structure during
 high winds, and bullets from pranksters' guns.   The gas  leak  problem made
 accurate oxygen consumption monitoring impossible,  and during the latter
 higher loading phases, the leaks became sufficiently frequent and large
 that it was extremely difficult to maintain a mixed liquor  D.O.  above
 1-2 mg/1.  The rationale for using an inflated dome in lieu of a flat cover
 on this research project was to permit access to the tank interior,  a
 procedure effectively utilized on several  occasions.   A  permanent install-
 ation would probably require a flat, more  rigid  cover  for longevity and
 minimization of leaks.
     The Cosmodyne  Division of Cordon International has  not attempted to
 establish a proprietary position with respect to the "SIMPLOX" system.
 Notwithstanding the attractive capital cost features of  this  oxygen
 dissolution concept for upgrading existing air-activated sludge  plants,
 without  the support of a proprietary interest and  an aggressive  marketing
 effort,  utilization of this process in treatment plant construction will
 most  likely proceed at a much  slower rate  than with other oxygen processes.

                           THE FMC PROJECT
     The FMC Corporation has developed a unique  fine-bubble diffuser capable
 of producing uniform oxygen bubbles of less than 0.2 mm  in  diameter.  The
 diffuser works on the shear principle of passing a high  velocity liquid
 stream at  right angles to  oxygen bubbles discharging into a vertical slot
 from  capillary tubes.  Oxygen gas is introduced  to the capillary tubes at
 30 psi pressure.,  A graph  provided by FMC  showing  water  depth required for
 complete dissolution of varying size oxygen gas  bubbles  is  reprinted in  Figure
 8.#  The large effect of a relatively small change in  bubble  size on the water
 depth required for  100 percent dissolution is readily  evident.   For  a bubble
 diameter of 0.20 mm, a 17.5 foot deep tank would be  required.  The  required
depth decreases  to  8.5 feet for a 0.15  mm diameter bubble.
     One of the many potential applications for  this diffuser is in an open-
#This graph was prepared using tap water.  Dissolution characteristics for
 various size oxygen gas bubbles may and probably do differ for a wastewater
 undergoing biological treatment.

                                      311

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             0.25
CO
i—'
no
        w
        H
        W
        ,-J
        cq
        cq

        CQ
        w
        o
            0.20
0.15
0.10
            0.05
                                     PARTIAL ESCAPE OF BUBBLES
                                                                                       BUBBLES COMPLETELY DISSOLVED
                        2           3      4     5    6   7   8  9  10          15


                         DEPTH OF WATER REQUIRED FOR  100% DISSOLUTION -  FEET
                                                                                                 20
30
40
                        FIGURE 8.   OXYGEN GAS BUBBLE DIAMETER VS. WATER DEPTH FOR COMPLETE DISSOLUTION

-------
tank  oxygen-activated sludge process.  To evaluate the feasibility of an
open-tank oxygenation approach, a research and development grant for
$142,000  was  awarded to FMC in September 1972 for a nominal 30 gpm pilot
plant study.   The firm is contributing over $75,000 of their funds to the
project.   The pilot plant has been installed on the grounds of the Engle-
wood, Colorado (suburb of Denver), trickling filter plant and receives a
feed  stream of primary effluent from that plant.  Pilot plant configuration
and dimensions are shown in Figure 9.  The aeration tank is provided with
two baffles to approximate a plug flow (three-stage) condition.  Diffusers
are located in each of the stages.  Mixed liquor is recirculated through
the diffusers by low head centrifugal pumps.  Pump suction is taken near
the liquid surface to promote mixing and tank turnover.  Throttling of the
oxygen feed is accomplished automatically by D.O. sensing and control.
     Major points of research interest in the project are:  (1) oxygen
utilization efficiency in an open-tank setting, (2) oxygen feed control
response based on a D.O. monitoring approach, (3) mixed liquor recirculation
rates and power requirements, (4) diffuser self cleansing (non-clogging)
capabilities, and (5) shearing effect, if any, on mixed liquor particles
caused by continuous recirculation through the pumps and diffusers.  In
the event that floe disruption did  occiu , a short detention biological
reflocculation tank (gentle mixing, no chemicals) was interposed
between the aerator and secondary clarifier.  Two aspects of system design
which cannot  be adequately defined at the scale of this pilot plant study
are diffuser  mixing characteristics and additional mixing requirements,
if any, for large aeration tanks.  This task is being addressed by FMC in deep
tank tests using tap water at both die firm's Englewood and Santa Clara
laboratories.
     Pilot plant fabrication was completed in late June 1973.  System
startup required the first 20 days of July.  The experimental program which
followed was  divided into eight phases and is outlined in Table 16.  Perform-
ance data for the four highest flow phases (Phase 4 through 7) are summarized
in Table 17.   Sludge characteristics, aerator loadings, and secondary clarifier
loadings for  the same four phases are presented in Tables 18, 19 and 20
respectively.  Data for the first three conservative load phases as well  as
Phase 8 which was still in progress at the date of this writing will be included
by FMC in the final project report.  Availability of this report is expected
by mid-1975.
                                      313

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                                 MIXED LIQUOR
MIXED LIQUOR
FLOCCULATION TANK
(IF NECESSARY)
                                                                             CIRCULAR CLARIFIER
                                                                          CENTER-FEED, RIM TAKEOFF
                                                                              10' DIA  x  10' WD
CO
I—>
-pi
        FROM  GASEOUS
        OXYGEN SUPPLY
                                                 THREE-STAGE
                                              OPEN  TANK AERATOR
                                          8'  LONG x 4'  WIDE x 11' WD
                                                                                              SECONDARY
                                                                                               EFFLUENT
                              RECIRCULATING  PUMPS
           PRIMARY
           EFFLUENT
                                                           FINE BUBBLE
                                                            DIFFUSER
                                                    RECYCLE SLUDGE
                                                                                                    WASTE
                                                                                                    SLUDGE
                                 FIGURE 9.   FMC OPEN-TANK OXYGENATION PILOT SYSTEM

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        TABLE  16.   PLANNED  EXPERIMENTAL PROGRAM FOR FMC PROJECT
Phase

1
2
3
4
5
6
7
8
Dates

7/21/73
9/6/73
12/6/73
4/8/74
5/1/74
6/1/74
7/1/74
10/1/74

- 9/5/73
- 9/30/73
- 1/28/74
4/30/74
5/31/74
- 6/30/74
- 7/31/74
10/31/74
Influent Flow
Condition

10 gpm (Constant)
10 gpm (Diurnal)
15 gpm (Constant)
25 gpm (Constant)
35 gpm (Constant
30 gpm (Diurnal)
20 gpm (Diurnal)
15 gpm (Constant)
No. of
Clarifiers
in use
1
1
1
2
2
2
1
1
            TABLE 17.   PERFORMANCE SUMMARY  FOR FMC PROJECT
                          (4/8/74 -  7/31/74)

Total BOD5 In (mg/1)*
Total BOD5 Out (mg/1)
% Removed
Total COD In (mg/1)*
Total COD Out (mg/1)
% Removed
Suspended Solids In (mg/1)-"
Suspended Solids Out (mg/1)
% Removed
Turbidity Out (JTU)
Sewage Temperature (°F)
4
153
-13
92
332
95
71
110
13
88
6
57
5
159
18
89
315
74
77
85
15
82
6
62
Phase
6
180
16
91
259
57
78
85
12
86
4
67
7
208
16
92
322
61
81
115
15
87
5
71
* Concentrations shown are for primary effluent  feed  to oxygen aerator.
                                   315

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        TABLE 18.   AVERAGE SYSTEM SLUDGE CHARACTERISTICS
                   FOR FMC PROJECT (4/8/74 -  7/31/74)
Phase



4
5
6
7
MLSS
(mg/1)


5,120
4,030
4,745
3,960
MLVSS
(mg/1)


4,010
3,435
3,860
3,365
Return
Sludge
Flow
(% of Q)
11,585
10,485
12,220
10,850
Return
Sludge
TSS
(mg/1)
60
52
57
50
SVI
(ml/gram)


71
70
67
73
SRT
(days)


2.0
1.5
2.1
2.6
             TABLE 19.   AVERAGE  AERATOR  LOADINGS FOR
                        FMC  PROJECT  (4/8/74-7/31/74)
Phase
4
5
6
7
Detention Time
-Based on Q-
(hr)
1.32
0.94
1.10
1.65
F/M Loading
/lb BOD5/day\
\ lb MLVSS J
0.69
1.17
1.01
0.91
Volumetric Organic
Loading
/lb BOD5/day\
^ 1,000 ft3 J
173
253
244
190
          TABLE 20.   AVERAGE SECONDARY  CLARIFIER  LOADINGS
                     FOR FMC PROJECT  (4/8/74-7/31/74)
Phase
4
5
6
x 7
* Excludes
Surface Overflow
Rate
(gpd/ft2)*
514
720
617
823
influent center-well annular
Mass Loading
/ lb Tss/ft2 y<-
\ dav /
35
37
38
41
area which = 9.1% of total
clarifier surface area.
                                  316

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     As  shown  in Table 17,  BOD^ and suspended solids removals during the
high loading conditions of  Phases 4, 5, 6, and 7 were excellent.  One of
the significant observations forthcoming from the project was that the
feared disruption of sludge settling properties due to floe shearing as the
mixed liquor was continually recirculated through the centrifugal pumps
and diffusers  did not materialize.  SVI for the above four phases averaged
a very acceptable 70 nil/gram.  A highly concentrated float (4-6 percent TSS)
approximately six inches thick quickly developed on the surface of the
aerator after startup.  This combination aeration/flotation effect was
anticipated in light of the fine  bubbles  created  by the  oxygen  diffusers.
It was found that the thickness of the float can be controlled by adjusting
the elevation at which the mixed  liquor recirculation suction is taken.
FMC personnel believe this feature offers a potential economically attractive
alternative location for extracting waste sludge from an activated sludge
system.
    In a full-scale embodiment of  this open-tank oxygen concept, mixed
liquor recirculation would not be accomplished by centrifugal pumps.
Instead, FMC envisions a propeller-type pump mounted inside a downcomer
draft tube.  The draft tube in turn is to be connected to a pipe header
containing many gas bar diffusers.  The whole assembly will rest on the
aeration tank  floor and will be  prevented from moving sideways by lateral
catwalks which are tied into the  top of the draft tubes.  Elevation, plan,
and side views of a full-scale aerator assembly as  currently proposed are
pictured in Figure 10.  A  perspective view of a typical  aeration tank
containing  several of these  assemblies and the resulting fluid mixing
pattern are shown in Figure  11.   This  system appears to  possess the
essential  ingredients for  significantly impacting the wastewater treatment
construction industry.
                                      317

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CJ
I—*
00
                                MOTOR PEDESTAL
                                THRUST BEARING
                             TOP OF COPING -
                                                                                                   WEATHER-PROOF
                                                                                                 - MOTOR       ""•
                                                                                                 -MOTOR PEDESTAL '.'.'_, WALKWAY
V

• / '
' i '
i\
\ -O-O '
a- -^- — r
1:

I
l!

*

•• DRAFT TUBE —

\ ' 1
// ^ \
^ x 7 \x y-
' /\ * w
.~.--7~r ; . . .". '~

s \
\
/ r.
' /' '•
'.'.-*' ' °
- "T^— :•-!
                          SUPPORT —
                                                                                                   SECTION A-A
                                   FIGURE 10.   ELEVATION,  PLAN,  AND SIDE  VIEWS OF ENVISIONED FULL-SCALE
                                                EMBODIMENT  OF FMC "MAROX"  OPEN-TANK  OXYGENATION SYSTEM

-------
FIGURE 11.  PERSPECTIVE VIEW OF ENVISIONED
      FULL-SCALE "MAROX" OPEN-TANK OXYGEN SYSTEM

-------
                       THE BLUE PLAINS PROJECT
     A multi-stage, covered tank oxygenation pilot system of Union Carbide
design (see Figure 12) was operated continuously from June  1970 through
September 1972 at the Joint EPA/District of Columbia (Blue  Plains) Pilot
Plant.  Nominal design throughput for the system was 70 gpm (100,000 gpd).
The results generated in over two years of work (believed to be the single
longest continuous oxygenation pilot plant study on record) were extensively
reported at the 1972 Water Pollution Control Federation Conference (Stamberg,
et al., 1972).  For a detailed summary of monthly operating data, the reader
is referred to the upcoming publication of this paper in the Federation
Journal.  Discussion of the project here is limited to generalized results
and observations.
     The oxygen system was operated over a wide range of SRT's from 1.3
to 13«0 days.  Hqwever, on District of Columbia (D.C.) primary effluent,
filamentous organisms propagate rapidly with either oxygen  or air if the
SRT is held below approximately five days for any extended  period of time,
producing a bulking sludge with greatly retarded settling rates.  Conse-
quently, the majority of the Blue Plains operation has been intentionally
restricted to SRT's greater than five days.  A technique devised by pro-
ject staff personnel of reducing the incoming flow and twin dosing the
sludge recycle stream with 200 mg/1 of hydrogen peroxide (based on influent
flow) for 24-hour periods at a one-week interval proved to  be an effective
method for purging entrenched filamentous bacterial growths from an acti-
vated sludge system.  The technique provides lasting benefit only if
subsequent F/M loadings are adjusted to maintain an SRT outside the critical
filamentous growth range.  The conditions under which filamentous cultures
propagate and flourish are unique to each wastewater and location.  Some
plants can operate in any desired loading range without encountering fila-
mentous problems.  Oxygen mixed liquor at Blue Plains was normally well
bioflocculated and essentially free of fragmented debris between discrete
particles.
     Above an SRT of five days, average system F/M loadings remained in
the range of 0.27-0.50 Ib BOD /day/lb MLVSS.  On those few  occasions when
                                  320

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OJ
                                         02 RECYCLE
                           —cfc-i
                        INFLUENT
                                         r<->0
                                                00
                                                                    n
oo
CO
                                                     T
                                                    SLUDGE RECYCLE
                         EXHAUST GAS
                                                                                J
                                 L
                                                                                              EFFLUENT
                                                                                              WASTE
                                                                                              SLUDGE
                        FIGURE 12.  SCHEMATIC DIAGRAM OF BLUE PLAINS OXYGENATION SYSTEMa
                         Reprinted with permission (Stamberg,  et al.,  1972)

-------
the system was operated at an SRT less than five days, F/M loadings  rose
to levels as high as 1.0 Ib BOD /day/Ib MLVSS.   Corresponding average
volumetric organic loadings at an SRT above five days ranged from 57-185 Ib
                o
BOD /day/1000 ft .  Aerator detention times (based on Q) were varied between
1.5 and 2.8 hours throughout the two-year+ period.  For all loadings
investigated, BOD  insolubilization was virtually complete.  Effluent
soluble BOD  residuals were never greater than 5 mg/1 and consistently
averaged 2-3 mg/1.  Total BOD  and suspended solids removal were a direct
function of clarifier performance.  Effluent COD and TOC concentrations
typically ranged from 35-60 and 15-20 mg/1, respectively.
     During the spring periods of rising wastewater temperature, nitrifi-
cation was established more slowly in the Blue Plains single sludge oxygen
system than in a parallel conventional single sludge air aerated pilot
system  probably due to  the  lower  mixed  liquor pH  inherent  in operation  of a
covered biological reactor.  Once established,  however, substantial nitri-
fication was exhibited by the oxygen system during warm weather.  With
decreasing wastewater temperature in the fall,  deterioration of nitri
cation was directly related to SRT.  At an SRT of 9.0 days and a wastewater
temperature of 63°F, at least partial nitrification was sustained.  However,
once the wastewater temperature decreased to about 60°F, no nitrification
was observed in the Blue Plains oxygen system up to an SRT of 13.0 days.
     Phosphorus removal experiments were conducted by adding aluminum
sulfate (alum) directly to the oxygen mixed liquor.  At an Al   /P weight
ratio of 1.4/1.0, phosphorus removal averaged 80% with total and soluble
phosphorus residuals of 1.8 and 1.6 mg/1 (as P) , respectively.  Increasing
the alum dose to an Al   /P weight ratio of 1.8/1.0 decreased total and
soluble residuals to 0.62 and 0.53 mg/1 (as P),  respectively, but it also
lowered mixed liquor pH from 6,5 to 6.0.  At the lowered pH, the oxygen
biota eventually dispersed and the experiments were discontinued.  For  low
alkalinity wastewaters such as the District of Columbia's, pH control may
be necessary to achieve efficient (90% or greater) phosphorus removal when
acidic metallic salts are added directly to oxygen-activated sludge mixed
liquor.
                                   322

-------
     Oxygen clarifier performance at Blue Plains and its effect on total
system operation are addressed in a later section.  Continued experiments
only recently completed  at  Blue  Plains  included evaluation of oxygen in a
step aeration flow regime and examination of the nitrification kinetics of a
second-stage oxygen system operating on full-scale D.C. modified aeration
effluent feed.  Reports on these activities are in preparation.

                  THE BUREAU OF RECLAMATION PROJECT
     The Bureau of Reclamation's Engineering and Research Center in Denver,
under an interagency agreement with EPA, has recently completed the second year
of a three-year project to test many different materials of construction to
evaluate their suitability for use with oxygen aeration wastewater treatment
systems.  The materials being tested include three different types of con-
crete, twelve different metals, and eleven protective coatings, linings,
joint sealers, and gaskets.
     The materials are being exposed for varying lengths of time to oxygen-
rich mixed liquor, oxygen-rich vapor above the mixed liquor, and to the
interface between the two phases and then withdrawn for examination.  Oxygen
reactors being utilized for these tests include Las Virgenes; Speedway,
Indiana; and Fairfax County, Virginia.  Interim results are available by writing
to EPA, Office of Environmental Engineering, Washington, D.C. (20460).

                     CRITICAL PROCESS PARAMETERS
     Certain process parameters are vital to the successful operation and
economic attractiveness of all waste treatment processes.  For oxygen
iteration systems, four of these process parameters are oxygen utilization
and consumption, sludge production, power consumption, and biological
performance versus biomass  loading.  Available data for the projects des-
cribed above are summarized below for each of the four parameters.
Oxygen Utilization and Consumption
     A misconception which seems to have accompanied the development of the
oxygcnation processes is that oxygen gas possesses mystical qualities and
can oxidize organics and ammonia nitrogen with  less oxygen consumption  than
air systemst  In reality, of course, the same amount of oxygen is required
                                      323

-------
to oxidize a given amount of organic carbon to carbon dioxide and water
or a given amount of ammonia nitrogen to nitrate nitrogen regardless of
the source of oxygen or the method in which it is delivered to a biologi-
cal system.
     The conventional method of calculating oxygen consumption in a
covered-tank oxygen system is to monitor inlet and exhaust gas flows
and effluent D.O. and assume that all oxygen not accounted for was con-
sumed.  This method will not detect any gas leaks which may develop in
and at the joints of the reactor cover.  A second method which is sensitive
to detecting sizeable leaks and can be used to check the gross accuracy of
the oxygen metering equipment is an oxygen balance technique recommended
by the Blue Plains staff (Stamberg, et al., 1972) and shown in Table 21.
The method assumes that one pound of oxygen is consumed for every pound
of COD destroyed (not to be confused with COD removed from the substrate)
and that 4.57 pounds of oxygen are consumed for every pound of ammonia
nitrogen converted to nitrate nitrogen.  The method is reasonably accurate
provided the wastewater does not contain certain industrial components
which do not consume oxygen in a COD determination but will utilize oxygen
in a biological system.
     Oxygen utilization and supply data for Newtown Creek, Batavia,
 Blue  Plains,  and  the FMC project  are  summarized  in Table  22.  Accurate
 measurement  of oxygen utilization  at  Las  Virgenes was  hampered due to
 excessive  gas  leaks  in the  tent cover previously described.  The table
 indicates  a  lack  of  informity  for  all three methods  selected for
 indicating specific  oxygen  supply requirements.  Generally,  in the
 absence of nitrification,  slightly more than  one pound of oxygen  should
 theoretically be  supplied  for  each pound  of COD  destroyed.  The Newtown
 Creek value  of 0.8 for the  period  of  September 17,  1972 through October  14,
 1972  cannot  possibly be correct  and indicates  probably either  low  inlet
 gas measurements  or  low waste  sludge  COD  determinations.   Of the three
.methods shown, designing oxygen  supply requirements  on the basis of  antic-
 ipated BOD5  removal  is the  least  reliable.  Since COD destroyed usually
                                    324

-------
                  TABLE 21.  OXYGEN BALANCE METHODS
Method 1:           Ib/mil gal Oxygen Supplied
             (  )    Ib/mil gal Exhaust Oxygen
                   Ib/mil gal Oxygen Utilized
                   Ib/mil gal Secondary Effluent D.O.
             (=)    Ib/mil gal Oxygen Consumed
Method 2:           Ib/mil gal Aerator Influent COD
             (-)   Ib/mil gal Secondary Effluent COD
             (  )   Ib/mil gal Waste Sludge COD

             (=)   Ib/mil gal COD Destroyed3
             (+)   Ib/mil gal Nitrate Nitrogen Oxygen Demand
             (+)   Ib/mil gal Exhaust Oxygen
             (+)   Ib/mil gal Secondary Effluent D.O.

             (=)   Ib/mil gal Oxygen Supplied (Theoretically)
rt
 Assumes 1 Ib COD destroyed consumes 1 Ib 09.
.                                           ^
 Assumes 1 Ib NH -N converted to 1 Ib NO.-N consumes 4.57 Ib 0~.
 cannot  be accurately  predicted  in advance,  using  an  oxygen required/
 anticipated COD removal weight  ratio of 0.60-0.75 and adding this to anticipated
 nitrification oxygen  demand,  if any, is probably  the best technique avail-
 able for sizing oxygen  supply equipment.  The  effect of  nitrification on
 oxygen  supply and  consumption is readily  apparent at Blue Plains  in May
 1972.   Generally,  but not  always,  less oxygen  was consumed per  pound of
 BOD  removed  as the F/M loading increased.   A  similar pattern was not evi-
 dent for oxygen consumed per  pound of COD removed.
                                      325

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                                     TABLE 22.  SUMMARY OF OXYGEN UTILIZATION AND SUPPLY
GO
ro
cr>
Plant
°2
Newtown Creek
Phase 1
Phase 2
Phase 3
Phase 4
Phase 5
Phase 6
Phase 7
Batavia
5/12/69-11/10/69
9/1/70-11/30/70
Blue Plains
May 1971°
May 1972d
FMC Proiect
Phase 4
Phase 5
Phase 6
Phase 7
Metered
Utilization
>90
>90
>90
>90
>90
>90
>90
93
92
97
97

-
-
-
F/M
/lb BOD5/day\
^ lb MLVSS )
0.65
0.57
0.57
0.92
1.19
1.62
2.44
0.59
0.87
0.97
0.36
0.69
1.17
1.01
0.91
lb Op Supplied
lb BOD Removed
1.09
1.20
1.39
1.02
0.88
0.83
0.79
0.94
1.36b
1.04
2.09
1.22
1.11
0.92
1.08
lb 02 Supplied
lb COD Removed
0.55
0.59
0.65
0.55
0.72
0.73
0.61
0.60
1.13b
0.60
1.03
0.72
0.65
0.75
0.79
lb 02 Supplied
lb COD Destroyed
0.80a
-
-
-
-
-
-
-
1.09
1.23

„
.
-
            Covers the segment of Phase 1 from 9/17/72-10/14/72 only.

            bValues are high due to high clarifier  loadings  resulting in  significant  solids  carryover and
             lowered BOD^ and COD removals.

            CNo nitrification.

            "Substantial nitrification.

-------
Sludge  Production
     Available data indicate that oxygen systems may produce less excess
biological  sludge than air systems at comparable F/M loadings.  The first
indication  was provided by the two Batavia projects as shown in Figure 13.
In this figure, BOD  removed per day per unit of MLVSS is plotted in the
conventional method against the inverse of SRT for both the air and oxygen
trains.  The curves reveal an approximate 50% reduction in favor of oxygen.
Although both of these trains were operated in plug flow configuration, the
comparison  is most likely heavily biased toward oxygen because of the severe
D.O. limitations under which the Batavia air reactor operated during these projects,
If oxygen does produce less sludge, it is probably due to the high mixed
liquor D.0« concentration maintained and the additional driving force it
provides for increasing oxygen penetration into and stimulating aerobic
activity within floe particle interiors.  Air system sludge production
data in which the mixed liquor is not devoid of D.O. for a lengthy section
at the head of the aerator (in contrast to Batavia) will provide more
meaningful  future comparisons with oxygen sludge production data.
     Reliable sludge production data are available from Newtown Creek for
Phases 4-7.  The data have been averaged for each phase and superimposed
on the Batavia sludge production curve in Figure 13.  Three of the four
points plot reasonably close to the line of best fit (or that line extended)
for the Batavia excess sludge production data, lending credibility to this
projection of oxygen sludge production for raw wastewater feed.  The fourth
point  (Phase 4), which represents the least loaded condition of the four
phases plotted, falls considerably above the Batavia oxygen sludge pro-
duction curve.  Additional sludge production data generated by the Newtown
Creek  oxygen system during the extended operating period of September 1973
through April  1974 are presented in the previously mentioned New York City
authored paper "Upgrading New York City Modified Aeration with Pure
Oxygen."  These additional data along with the data summarized in this report
provide an accurate representation of oxygen system sludge production at
Newtown Creek over a substantially broad range of loadings.
                                      327

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1.3
   -   1.31
                                                                                                 V
1.1
 1.0
0.9
o.e
                                            BATAVIA OXYGENATION 	
                                            SYSTEM SLUDGE PRODUCTION
                                            CURVE EXTENDED
     0.93
     0.76
EXCESS VSS FORMATION
  CORRELATIONS  AND
95% CONFIDENCE  LIMITS
FOR PREDICTED VALUES

    1969 AND 1970
                                    *  BATAVIA
                                    / AIR  AERATION SYSTEM
                                               957. CONFIDENCE
                                                    LIMITS
          • BATAVIA OPERATIONS
                              /_
O.7
   .  0.73
0.5
0.4
0.3
0.2
O.I
                    A /
                                                   /
                 9
              ^crf-
                                                    BAT AVI A
                                                    OXYGENATION
                                                    SYSTEM
              //
           /
                                 BATAVIA LEGEND FOR
                                 WEEKLY DATA POINTS
                                                                /A
              /
CODE
A
A
D
Q
O
O
SYSTEM
AIR
AIR
OXYGEN
OXYGEN
OXYGEN
OXYGEN
YEAR
1969
1969
1969
1969
1970
1970
PHASE
I
m
i
JL
i
or
                                                                           NEWTOWN CREEK
                                                                              LEGEND

                                                                            PHASE 4 AVG.

                                                                            PHASE 5 AVG.

                                                                          - PHASE 6 AVG.

                                                                            PHASE 7 AVG.
                                                                                                col
                                                                                                |H
                                                                                                CM
          0.2
                   0.4
                           0.6
                                    0.8
                                              1.0.
                                                      1.2
                                                               L4"
                                                                                 l.«
                                                                                         2.0
                    LB BOD REMOVED/OAY/LB MLVSS
        FIGURE  13'.   NEWTOWN CREEK EXCESS  OXYGEN  SLUDGE PRODUCTION DATA SUPER-
                      IMPOSED ON  BATAVIA EXCESS  SLUDGE  PRODUCTION  CORRELATIONS PLOT
                                                                                                2.2
                                            328

-------
     Sludge  production data for the Blue Plains oxygen system are compared
with data  from a parallel step aeration air pilot system operated on the
same primary effluent feed in Figures 14 and 15 (Stamberg, et al., 1972).
Figure 14  plots SRT versus F/M loading and indicates that less volatile
mass under aeration was required with oxygen to reach any given SRT above
six days.  Blue Plains personnel attribute the increased activity of the
oxygen volatile mass to maintaining mixed liquor D.O. between 4 and 8 mg/1
and the minimization of sludge pockets and dead spots afforded by independ-
ently controlled mixing.  Figure 14 can be manipulated to produce Figure 15
by multiplying F/M values by the corresponding SRT values and inverting
the product  to yield volatile solids produced per unit of BOD,, applied and
then replotting these new values against SRT.  Figure 15 shows substantial
reduction  in sludge production with oxygen again above an SRT of six days.
Below an SRT of about eight days, the step aeration system experienced
soluble BOD5 breakthrough and overall effluent quality was poorer than
that of the  oxygen system.  Because of the different flow configurations
utilized,  sludge production information generated by these two systems
cannot be  used directly to derive conclusions regarding the relative sludge
production rates of oxygen and air at comparable SRT's.  The kinetics of
step aeration dictate that it will experience maximum sludge production
at a much  higher SRT than a plug flow regime.
     In an attempt to compare sludge production data from air and oxygen
systems with similar operating conditions and with the further restriction
that the air system is not oxygen transfer limited, data from the Hyperion
Plant in Los Angeles (Smith, 1969) are plotted against the Blue Plains data
in Figure  16 on a BOD,, removed basis and Figure 17 on a COD removed basis.
Hyperion is  an air activated sludge plant with a consistent record of excellent
performance and adequate mixed liquor D.O.   Both Hyperion and  Blue Plains data
were collected on systems operated in a conventional plug flow mode on primary
effluent feed.  In Figure 16 a majority of the oxygen points fall below the
Hyperion regression curve and Smith's computer program curve for Hyperion.
In Figure  17 all but two of the oxygen points fall below the air curve, many
of them well below.  These two figures lend  additional support to the position
                                      329

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CO
CO
O
                                 1.0,-
                                 0.8
                            GO
                            GO
                            S   0.6
0.4
                                0.2
                                                          STEP  AERATION
                                                    I
                                    I
I
I
                                    0       2        4        6        8       10       12

                                                      SLUDGE RETENTION TIME-SRT (days)


                             FIGURE 14.  BIOLOGICAL ACTIVITY RELATIONSHIPS  - BLUE PLAINS

                            aReprinted with permission  (Stamberg,  et al., 1972)
                                                            14
                        16

-------
CO
CO
                             ca
                                 1.0
                                 0.8
                             CO

                             s  0.6
en
o_

oo
                                 0.4
                                 0.2
                                                                                     I
                                                   46        8       10       12

                                                      SLUDGE RETENTION TIME-SRT (days)
                                                               14      16
                             FIGURE  15.   EXCESS BIOLOGICAL SLUDGE PRODUCTION - BLUE PLAINS

                             aReprinted with permission  (Stamberg,  et al. ,  1972)

-------
                    1.0  i—
00

CO

IX)
                Ci
                LU
                co
                CO
                co
<  0.5
Q


Q
LU
Q

O

a.


CO


CO
—i
II
t—

CO
                                                                   O =HYPERION (AIR)


                                                                   A =BLUE  PLAINS

                                                                        (OXYGEN )
                                                                            _L
                                  0.2         0.4        0.6         0.8         1.0


                                  LB BOD5 REMOVED/DAY/LB MLVSS IN AERATOR
                                                                             1.2
                       FIGURE 16 .  COMPARISON OF SLUDGE PRODUCTION FOR AIR AND OXYGEN SYSTEMS

                                  ON PRIMARY EFFLUENT FEED (BOD5 REMOVED BASIS)

-------
                    1.0 i—
CO

CO

CO
                cm
                LU
                to
                to
                ca
O
LU
U
ID
Q

O
                 01
                 CO
                 03
                 _i

                 II
                 h-


                 CO
                    0.5
                                   1
                                                    0=HYPER!ON (AIR)

                                                    A=BLUE PLAINS

                                                       (OXYGEN)
                               I
I
I
I
I
                                  0.4         0.8          1.2          1.6         2.0


                                    LB COD REMOVED/DAY/LB MLVSS IN AERATOR
                                                                                           o -
                                                                              2.4
                 FIGURE  17.  COMPARISON OF SLUDGE PRODUCTION FOR AIR AND OXYGEN SYSTEMS ON
                           ^PRIMARY EFFLUENT FEED (COD REMOVED BASIS)

-------
that reduced sludge production is probable with oxygen, but not  to  the
degree predicted from the Batavia projects.  Additional comparative data
under similar operating conditions and on the same wastewater feed  are
neededo  The current Detroit expansion is a good cand- date for supplying
such information when  large-scale air and oxygen modules now in the
final stages of construction and/or startup are ready for parallel
operation.
     Available sludge production data for Newtown Creek, Batavia, Las
Virgenes, and the FMC project and two typical months of data for Blue
Plains are summarized in three forms in Table 23 along with the corres-
ponding F/M loadingSo  This table illustrates the general futility  of
attempting to correlate sludge production data from one location to
another by any of the three methods shown.  Many local factors including
wastewater composition, wastewater temperature, mixed liquor D.O.,  and the
biodegradability rate of various organic constituents combine to influence
the amount of excess sludge that will be formed at different plants under
similar loading conditions=  Table 23 also shows that even at a single
plant, unit sludge production on a BOD  or COD removed basis does not
necessarily increase with increasing F/M loading, or vice versa.  If any
rational method exists for representing sludge production at a single
location or comparing sludge production among locations, it is probably
the basic inverse SRT method utilized in Figures 13, 16, and 17, or one
of several published modifications of this basic method,
Power Consumption
     One of the more attractive economic aspects projected for oxygenation
systems from the Batavia work is greatly reduced power requirements for
oxygen supply (generation) and transfer (dissolution) compared with the
power requirements of air blowers.  Estimated installed HP load require-
ments as projected from the Batavia work are plotted against plant  size
and BOD  aerator loading for both oxygen and air systems in Figure  18.
The oxygen system band represents the additional power requirement  for
mixing as aerator volume is increased from one hour detention to two hours
detention (based on Q).  The air system band encompasses blower supply
rates from 0.8 to 2.4 cubic feet of air supplied per gallon of wastewater
                                   334

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                                                TABLE 23.  SUMMARY OF OXYGEN SYSTEM SLUDGE PRODUCTION
OJ
CO
en
Plant
Newtown Creekc
Phse 4
Phase 5
Phase 6
Phase 7
Bataviac
7/21/69-9/7/69
8/30/70-10/25/70
Las Virgenesd
Phase 1
Phase 2
Phase 3
Phase 4
Phase 5
Phase 6
Phase 7
FMC Projectd
Phase 4
Phase 5
Phase 6
Phase 7
Blue Plainsd
Sept. 1971
Feb. 1972
F/M Loading lb
/lb BOD^/day\
^ lb MLVSS )
0.92
1.19
1.62
2.44
0.79
0.52
0.07
0.11
0.15
0.24
0.33
0.41
0.46
0.69
1.17
1.01
0.91
0.39
0.30
Waste Sludge TSSa
mil gal
1,300
1,185
1,055
1,025
970
1,250
-
91
103
250
250
123
1,086
730
752
878
620
430
lb VSS Produced*3
lb BOD Removed
0.94
0.73
0.59
0.60
0.41
0.52
0.19
0.14
0.15
0.14
0.27
0.31
0.21
0.80
0.62
0.50
0.53
0.38
0.47
lb VSS Produced13
lb COD Removed
0.49
0.59
0.51
0.46
0.35
0.29
0.13
0.09
0.08
0.05
0.13
0.15
0.09
0.47
0.36
0.41
0.39
0.25
0.23
                        •Includes waste sludge TSS  only.                 cRaw sewage feed.
                        blncludes waste sludge and  final  effluent VSS.  d'Srima.ry effluent feed.

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 oc
 LU
 U-
 10
 Z
O
Z
a.
a.
to
Z
LLJ
O
X


O
u_
D

O

a.
CO
Z
    10,000
                 LB BOD5 APPLIED TO  AERATOR PER DAY

         1,000                   10,000                   100,000
               ™
              / m
      1,000
       100
        10
                          I  I   I I  I I
        AIR SYSTEM BLOWERS

        OXYGEN  SYSTEM
        DISSOLUTION AND
        GENERATION
        EQUIPMENT
SYSTEM POWER ESTIMATES
BASED ON BATAVIA DATA

       0.8 FT3/GAL

  1.6 FT 3/GAL
             2.4 FT3/GAL  A
                                          1,005 HP

                                         1,041 HP

                                       905 HP

                               1 HR DETENTION

                              2  HRS DETENTION
                  0 NEWTOWN  GREEK-
                    DESIGN CONDITION

                    NEWTOWN  CREEK-
                    OPERATING  CONDITIONS
                  A — PHASE 1 AVG.
                  EJ— PHASE 7 AVG.
             I   I  I  I I I
                                                    1  1   1111
           1                         10                       100
                           PLANT SIZE-MGD
      (BASED ON AVG.  AERATOR  INFLUENT BOD5 OF  130 mg/l)
     FIGURE 18.   NEWTOWN CREEK POWER CONSUMPTION SUPERIMPOSED
                 ON BATAVIA POWER PROJECTION CURVES
                                336

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treated.   Using the median of the bands, 50% and 65% reductions in aeration
power requirements are projected for oxygen over air at plant sizes of 1
and 100 mgd, respectively.
     Plotting the installed HP load for oxygen supply and dissolution at
Newtown Creek on this curve indicates oxygen system power requirements
estimated from Batavia may be somewhat optimistic.  The installed HP load
at Newtown Creek is 1041 HP, as broken down in Table 24, for a design load
of 41,700 pounds of BOD  per day (calculated using a BOD5 of 250 mg/1 at
20 mgd).   The Batavia curve predicts an installed nameplate requirement  of
only 550-800 HP for the same design BOD  load.
       TABLE 24.  INSTALLED HP AT NEWTOWN CREEK FOR
                  OXYGEN GENERATION AND DISSOLUTION

          Item                                           Nameplate HP

1.  PSA Compressor                                          450
2.  Liquid Oxygen Vaporizer                                  96
3.  1st Stage Compressors at 40 HP ea                        80
4.  2nd,  3rd, and 4th Stage Compressors at 40 HP ea         120
5.  1st Stage Mixers at 50 HP ea                            100
6.  2nd,  3rd, and 4th Stage Mixers at 30 HP ea              180
7.  PSA Cooling Tower Pumps                                   8
8.  Instrument  Air Compressor                                 7
                                               Total      1,041
      The strength of  the Newtown Creek wastewater during the  project
 was  somewhat weaker  than the design projection.   The actual  BOD^  load
 for Phase 1 averaged  only 29,650 pounds per day (29 percent less  than
 the design load)  even though the average flow of  20.8 mgd was slightly
 higher than the design flow of 20 mgd.  However,  actual power consumption
 for the same period averaged 905 HP, a decrease of only 13 percent from
 the installed load.  This demonstrates a well-known fact that non-variable
 speed drives operating below design load will consume almost  as much power
                                   337

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as when operating at design conditions.   Consequently,  power consumption
for Phase  1 when superimposed on Figure  18  falls  well  above the oxygen
band and up near the median of the air band.
     The converse situation is illustrated  in Phase  7  when,  due to the
increased  average influent flow of 35.4  mgd, the  BODj.  load  to  the aerator
averaged 62,645 pounds per day.  Oxygen  supply and dissolution requirements
consumed an average power draw of 750 kilowatts (equivalent to 1,005  HP).
Thus, with an actual power consumption 3.5  percent less  the installed load,
the system satisfactorily treated a BOD,,  loading  50  percent  greater than the
design load.  For this phase, power consumption plots  near  the median of the
Batavia oxygen  band in Figure 18.
     From  the above data it is apparent  that actual  unit power consumption
for oxygenation systems will approach installed unit power  consumption
only when  operating at or near design organic load.  Another conclusion which
can be drawn from Newtown Creek experiences is that  the oxygen module1 s oxygen
transfer equipment was substantially overdesigned for  the projected
BOD  load.
   5
Biological Performance Versus Biomass Loading
     A strong point of oxygenation system performance noted wherever  oxygen
has been tested is the relative insensitiveness of effluent quality to
changes in F/M loading.  Data accumulated from Batavia, Newtown Creek, Blue
Plains, and Las Virgenes are plotted in Figure 19.   These data indicate
plateaus for soluble BOD,, and soluble COD breakthrough of only about  15 and
60 mg/ls respectively, up to F/M loadings of 2.4  Ib  total BODs applied/day/lb
MLVSS.   This denotes consistent and impressive performance under  stressed
conditions.  At the lower loadings employed at Blue  Plains, essentially
complete insolubilization of BOD  is evident.  For all F/M  loading  rates,
however, total system efficiency for oxygen processes will be  more  directly
dependent on solids capture efficiency (clarifier performance) than on
biological performance deterioration.
                                    338

-------
CO
CO
         80
Q
§
W
J
§  8
       W 0
O =BATAVIA
A =NEWTOV/N  CREEK
D =BLUE PLAINS
X =LAS VIRGENES
                O
                                                                GO,
                 I	I
                                                                I    1     I	I
                                                                                   I
                                  0.5
                                                   1.0                     1.5

                                          F/M LOADING - LB BOD5 APPLIED/DAY/LB MLVSS
                                                                                         2.0
                                                                                                                            80
                                                                                                                             0

                                                                                                                            16
                                                                                                                                       O
                                                                                                                                       O
                                                                                                                                       w
                                                                                                                                       O
                                                                                                                                       C/D
                                                                                                                                       Pu
                                                                                                                                       tu
                                                                                                                                       W
                                                                                                                j	i	i	I
                                                                                                                                 2.5
                                           FIGURE 19.   EFFECT OF F/M LOADING  ON  OXYGEN
                                                     SYSTEM EFFLUENT SOLUBLE  BOD5  AND COD

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                  SLUDGE SETTLING AND SYSTEM DESIGN

     Perhaps the most important information generated by the  Blue  Plains
project has been a delineation of some of the factors affecting  sludge
settling at that site and its resultant effect on system design  (Stamberg,
et al., 1972)o   In addition to the retardent effect on sludge  settling
previously mentioned due to filamentous infection of mixed  liquor,  other
factors which affected oxygen sludge settling rates at Blue Plains  included
solids concentration, bulk sludge density (volatile solids  fraction), and
wastewater temperature.
     In the range of MLSS concentrations at  which hindered  or zone
settling occurs, it has  been found that an equation in the form  of  v.= aC.
where v. = initial settling velocity
      C. = initial solids concentration
       i
      a = intercept constant
      n = slope constant

when plotted on log-log  paper yields a straight line.   Further, it has been
shown such a relationship exists for each of the three types of settling,
discrete particle, hindered, and consolidation settling (Dick, 1970)(Duncan,
et al., 1968).   The change in slope between  discreet particle settling and
hindered settling normally occurs at a C.  between 2000 and  3000 mg/1.  The
hindered settling zone is characterized by a discrete subsiding interface  and
a zone of homogenously mixed settling particles.  Clarifiers operating with
initial hindered settling are in reality operating as sludge thickeners.
It is essential that both hydraulic and mass loadings be considered in the
                                    340

-------
design of secondary clarifiers for high solids systems.  In many cases,
thickening (mass loading) requirements will control the design.  The
best available approach for evaluating thickening requirements appears
to be the batch flux (mass x settling velocity) method (Dick, 1970).
     Bulk sludge density is a function of volatile solids fraction, i.e.,
density increases with decreasing volatile fraction.  The incorporation
of denser inerts into the sludge mass is the primary reason why biomasses
developed on raw wastewater will generally settle better than those
developed on primary effluent.  Another manner in which sludge density
is temporarily affected is the washing of accumulated inerts into a plant
from its sewer system during rain storms.  This point was vividly illus-
trated at Blue Plains during a tropical storm the summer of 1972 as  shown
in Figure 20 «
     The least, recognized parameter prior to plant startup that eventually
strongly affected oxygen sludge settling rates at Blue Plains was waste-
water temperature.  Settling rates decreased significantly from summer to
winter operation.  For example, during September and October  1971 (a
period when the oxygen clarifier was operated with a deep center feed
below the sludge blanket to capture unsettleable particles) as wastewater
temperature dropped from 81° to 71°F, the initial settling  rate (ISR)
decreased from 10 ft/hr to 7 ft/hr in a 1-liter graduated cylinder test
at an MLSS concentration of 6000 mg/1 (see Figure 21).  In November of
the same year the center feed was raised above the blanket in an attempt
to purge unsettleable particles from the system and increase bulk sludge
density.  While this technique did increase the sludge density and tem-
porarily the ISR, a similar temperature effect was noted over the two-
month period of November and December  1971.  As wastewater temperature
dropped from 70° to 63°F, the ISR decreased from 14 ft/hr to 9 ft/hr at
an MLSS concentration of 4500 mg/1 (see Figure 22).  Conversely, as Blue
Plains wastewater temperature increased in the spring and summer of 1972,
substantial increasing settling rates were observed as illustrated in
Figure 23.  The net result of this phenomenon was that a peak oxygen
                                      2
clarifier overflow rate of 1940 gpd/ft  was possible in the summer of 1970
with an MLSS of 8000 mg/1, while the peak overflow rate that could be
                                   341

-------
         100

          80


          60

          50

          40


     ~  30

     -c=


     4±   20
      CL3

      S   10
      UJ
      :>•    8
      2=    6
      •=;    5
      t    4
      oo
JUNE 22-JULY  3, 1972

    (TROPICAL STORM)



        10-20, 1972
                         I	I
                         3  4  5678910
                     20   30  40   60  80 100
                       INITIAL MLSS CONCENTRATION (gm/l)
FIGURE 20.   ILLUSTRATION OF  INCREASED SLUDGE DENSITY CAUSED BY RAIN  a

            STORM AND  ITS  EFFECT ON INITIAL SLUDGE SETTLING VELOCITY
 Reprinted with permission (Stamberg, et al., 1972)
                                 342

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    30




    20



j=  15




^  10

£   8
o

UJ   n
>•   D


SE

e   4
UJ

^   '3
        1
                                      D.C.-Sept 1971-[78-81°F)
               D.C.-Oct 1971-[71-73°F)
                                                        I	I
         1           2      34       6    8  10     15   20     30


              INITIAL MIXED LIQUOR  CONCENTRATION  (gm/l)
FIGURE 21.  EFFECT OF DECREASING WASTEWATER TEMPERATURE ON INITIAL SLUDGE


          SETTLING VELOCITY  (SEPTEMBER-OCTOBER, 1971)&




Q

Reprinted with permission (Stamberg, et al.,  1972)
                                 343

-------
     30



     20


]jf   15




S   10
£3    Q



£    B
CD


I    4
LU

^    3
«C

t:
     1
                             D.C. -Nov  1971-(68-70°F)
                                D.C.-Dec  1971-(63~64°F)
                         1    I
I     I   I
I     !
I
      1          234      6   8   10    15  20      30



            INITIAL MIXED LIQUOR CONCENTRATION  (gm/l)



FIGURE 22.  EFFECT OF DECREASING WASTEWATER TEMPERATUREaON INITIAL  SLUDGE

          SETTLING VELOCITY (NOVEMBER-DECEMBER,  1971)


a
 Reprinted with permission (Stamberg, et al.} 1972)
                              344

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           40

           30


           20
1972


JUNE 10-
[70°F-74
                                i    i    i   i  i  r

                              JUNE 22-JULY 3,
                    (72°F-76°F]
      CD
10

 8
 7
 6
 5
               MAY 20-31,
               (66°F-71°F)
                        1-
                  (63°F-65°F)
                                  JULY
                                10-25,
                              F-79°F)
                                 3    456    8  10
             INITIAL MLSS  CONCENTRATION (gm/l)
FIGURE 23.  EFFECT OF RISING WASTEWATER TEMPERATURE ON INITIAL
          SLUDGE SETTLING VELOCITY (SPRING-SUMMER, 1972)a


&Reprintcd with permission (Stamberg, et  al.,  1972)
                          345

-------
sustained in either the 1970-71 or 1971-72 winters without clarifier
                      2
failure was 975 gpd/ft  at MLSS levels that varied from 3900-5300 mg/1.
     Undoubtedly all of the factors discussed above contributed to the reduced
overflow rates necessary at Blue Plains to maintain satisfactory winter clarifier
operation.  However, it appears that wastewater temperature played a
major role at this site.  It is strongly emphasized though that the con-
clusions drawn from the Blue Plains project regarding wastewater tempera-
ture and sludge settling are not intended to imply that a similar effect
will be noted universally. Much additional data are needed to reach a
more definitive conclusion.  Some additional data were collected over a
period of about 20 months at Newtown Creek (raw wastewater feed) and
Speedway, Indiana (primary effluent feed),,  Batch flux settling tests
were conducted periodically at both sites using slowly stirred
six-inch diameter, eight-foot long settling columns.  Settling
velocity profiles as a function of initial MLSS concentration are plotted in
Fig. 24 for three runs conducted at Newtown Creek in December 1972 and June and
August 1973.  These plots tend to verify the temperature effect observed
at Blue Plains.  The decreased settling rates noted in the winter at Newtown
Creek are probably due to a combination of increased viscosity and drag of
the wastewater and alteration of biomass characteristics (proliferation of
filamentous organisms) at the colder water temperature.
     Results of the long-term Blue Plains work illustrate clearly that
oxygen system design should be thought of as an integrated package con-
sisting of a biological reactor, a secondary clarifier, and sludge handling
facilities.  The system should be designed for the worst anticipated climatic
conditions at a given site.  Clarifier sizing should be specifically tailored
to the design and anticipated operating conditions of the reactor.  There
are two basic ways of achieving a desired F/M loading:  (1) a small reactor
and high MLSS or (2) a larger reactor and lower MLSS.  If the first method
is selected to save on reactor costs, a larger clarifier will be necessary.
Both a small reactor and a small clarifier cannot be successfully mated in
a design unless greatly reduced MLSS concentrations are utilized.  However,
opting for this selection will increase F/M loading, excess biological
sludge production, and required sludge handling capacity and costs.
                                     346

-------
Pi
H
H
U
O
,-)
W
H
W
C/3

i-J
<
H
H
H
z;
40




30





20



15





10


 8
 4



 3
                                           June 20,  1973  (22°C)
                                           Aug. 8, 1973  (26°C)
          Dec. 10, 1972 (17°C)
                     2        34       6     8   10      15   20       30


                   INITIAL  MIXED LIQUOR CONCENTRATION (GM/L)



              FIGURE 24.   SETTLING VELOCITY PROFILES FOR BATCH

                           FLUX SETTLING TESTS CONDUCTED AT NEWTOWN  CREEK
                                   347

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                          PROCESS ECONOMICS
     No updating of the comparative cost estimates presented for air and
oxygen systems in the Batavia II final project report (17050 DNW 02/72)
has been attempted in this paper.  Figure 25 summarizes estimated total
treatment costs (including amortization, operation, and maintenance) for
air and oxygen systems of 1-100 mgd capacity as taken from the Batavia II
final report.  Interest was figured at 5-1/2% over 25 years.  Oxygen
supply costs are based on on-site generation plant purchase by the
municipality.  Projected savings in the cost of oxygen by buying and
operating your own plant as opposed to commodity across-the-fence purchase
current at the time of printing of the Batavia I final project report
(17050 DNW 05/70) are shown in Figure 26.
     Figure 25 projects average savings in total treatment costs of about
20% with oxygen for plants of 20-100 mgd«  It must be remembered, however,
that built into these curves are:  (1) the assumption questioned by many
observers that oxygen reactors will universally be one-third as large as
air reactors for equal treatment and (2) what is believed to be overly
optimistic estimates of the difference in sludge production rates between
air and oxygen processes.  The author concludes the one area in which
oxygenation may have a very decided economic advantage is in the upgrading
of existing overloaded secondary plants, such as Newtown Creek.  Also it
is likely that many decisions to install oxygen are not made so much on
the basis of economics as on the basis of the high process reliability
and stability and the rapid recovery following toxic upsets afforded by
an enriched oxygen biological system.
                                   348

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                20
40          60
PLANT SIZE-MGD
80
100
FIGURE 25.  TYPICAL RANGES FOR TOTAL TREATMENT COSTS FOR NEW PLANTS
           WITH PRIMARY  SEDIMENTATION PROJECTED FROM BATAVIA STUDIES
                              349

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GO
en
O
                         120
                         100
                          80
                        y eo
                        cr
                        a.
UJ
o

x 40
O
                          20
                                                                                   ON-SITE  GAS PURCHASE
                               ON-SITE
                               PLANT PURCHASE
                                    J	1
                                                                J	I
                                                                                      I	I
    0.2      0.5     I      2        5      10     20      50

                       OXYGEN USAGE RATE — TONS / DAY
                                                                                     100   200      500   1000
                                       FIGURE 26.  OXYGEN  COSTS AS A FJNCTION OF USAGE RATE

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                        CONTINUING DEVELOPMENTS
Continuing Research and Development Projects
     Continuing EPA research and development efforts are underway or recently
completed in the following areas:  (1) evaluation of second-generation oxygen
dissolution approaches, (2) examination of oxygen nitrification kinetics both
in single-stage and two-stage systems, (3) definition of viable alternatives
for combining chemical phosphorus removal with oxygen aeration, (4) determin-
ation of the most cost-effective sludge handling and dewatering techniques for
taking advantage of the excellent thickening properties of oxygen sludge,
(5) examination of sludge settling characteristics, (6) investigation of
aerobic sludge digestion with oxygen gas, and (7) a study of the safety
aspects of using oxygen in a wastewater treatment plant environment.
     The development and maturation of new wastewater treatment processes are
usually accelerated by the parallel development of several proprietary systems.
However, because of this more rapid development, certain process details and
aspects not directly associated with the treatment of wastewater often do
not receive as thorough an evaluation as may be desirable and prudent.
The safety aspects and requirements of utilizing oxygen in activated sludge
treatment (No. 7 on the above list) are believed to represent one such aspect.
Although each firm marketing an oxygen aeration system has undoubtedly
considered safety features and requirements for its particular system,
no comprehensive generalized treatment of the subject has been undertaken,
until recently.  Of particular concern is the processing of wastewaters
which periodically contain hydrocarbons and other volatile substances in
covered aeration systems with oxygen atmospheres ranging anywhere from 50
to 95%.  The fundamental safety ramifications of using oxygen in this type
of duty have needed an in-depth review and evaluation by an independent
investigative team.  A standard safety manual has also been urgently needed
to instruct waste treatment plant designers and operators in the safe and
proper handling of oxygen and to identify essential safety equipment and
instrumentation.  Such a manual must be sufficiently broad and comprehensive
to apply to any rational concept for dissolving oxygen in wastewater.
                                     351

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     Due to lack of funds, this project was delayed for more than
a year.  In June 1974, however, a contract was awarded to the Rocketdyne
Division of Rockwell International to undertake this study.  The
purpose of the project is twofold:
     (1)  To evaluate the fundamental ramifications and implications from
          a safety standpoint of using-oxygen gas or oxygen enriched air
          for aeration of activated sludge systems and based on this
          evaluation to recommend an implementive course of action which
          will ensure the safety and security of wastewater treatment plant
          personnel and facilities.
     (2)  To develop a standard safety manual and safety checklist for
          the safe and proper handling of oxygen in a wastewater treat-
          ment plant environment that will apply in principle to any
          rational oxygen dissolution concept.
Oxygen Process Implementation
     Oxygenation systems are being designed and constructed for many
treatment plants across the country to meet a variety of new plant con-
struction and plant upgrading needs.  At the time of this writing, 48
known  municipal  oxygen  systems  are  in various  stages of  design, construction,
startup,  or  operation.   As  summarized in  order of decreasing size
in Table  25, the total design flow of these 48 plants is 2S714.8 mgd ranging
in capacity from 0.9 to 600 mgd.  Of the 48 plants,37  are designed using
surface aerators for oxygen dissolution,eight  with submerged turbines, one
with fine-bubble diffusers (open-tank),  one (Las Virgenes) employed a
converted air blower and air diffusers,  and one is still undetermined.
     Oxygenation is also beginning to make inroads into the industrial
wastewater treatment picture.  As indicated in Table 26, eight  systems
are currently being constructed and/or operated to treat a variety of
industrial wastes.  The total design flow of these_eight systems is 62.9
mgd ranging in size from 1 to 25 mgd.  Six oxygenation systems  are now also
on-line in Japan.
     Preliminary oxygen designs are being prepared for 30-40 additional
plants still in the negotiating phase.  It appears that oxygen aeration
is definitely here to stay.
                                    352

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   TABLE 25.  MUNICIPAL WASTEWATER TREATMENT  PLANTS  UTILIZING OXYGEN
Plant
1.
2.
3.
Detroit, Mich.
Detroit, Mich.
Philadelphia, Pa.
Design
Flow
(mgd)
600
300
210
Type of
Dissolution
System
Submerged Turbines
Submerged Turbines
Surface Aerators
Status
(Oct. 1974)
Design
Startup
Design
    (Southwest)
    Philadelphia,  Pa.
    (Northeast)
    New Orleans, La.
    Middlesex County, N.Jo
7-  Oakland,  Calif.
    (East  Bay M.U.D.)
8.  Dade County,  Fla.
9.  Louisville, Ky.
10. Wyandotte, Mich.
11. Denver,  Colo.
12. Baltimore, Mel.
13. Tampa, Fla.a
14. Miami, Fla.
15. Duluth,  Minn.
16. Hollywood, Fla.
17. Cedar  Rapids, Iowa
18. Ilarrisburg, Pa.
19. Springfield,  MD.
20. Salem, Ore.
21. Danville, Va.
22. Euclid,  Ohio
23. Ft. Lauderdale,  Fla.
24. Littleton/Englewood, Colo.
25. New York, N.Y.  (Newtown Creek)
26. Decatur,  111.
150
Surface Aerators
122    Surface Aerators
120    Submerged Turbines
120    Submerged Turbines

120    Surface Aerators
105    Submerged Turbines
100    Submerged Turbines
 97    Surface Aerators
 73    Surface Aerators
 60    Surface Aerators
 55    Surface Aerators
 42    Surface Aerators
 36    Surface Aerators
 32.9  Surface Aerators
 31    Surface Aerators
 30    Surface Aerators
 26.5  Surface Aerators
 24    Surface Aerators
 22    Surface Aerators
 22    Surface Aerators
 20    Surface Aerators
 20    Submerged Turbines
 17.7  Surface Aerators
Design

Const.
Const.
Const.

Design
Const.
Const.
Const.
Design
Design
Design
Design
Const.
Design
Design
Design
Const.
Const.
Const.
Design
Design
Oper.
Const.
aTwo-stage oxygenation system.
                            (CONTINUED)
                                    353

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(CONTINUED)
TABLE 25. MUNICIPAL WASTEWATER TREATMENT PLANTS UTILIZING OXYGEN
Plant
27.
28 0
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45 o
46.
47-
48.
Fay ett evil le, N.C.
Chicopee, Mass.
New Rochelle, N.Y.
Muscatine, Iowa
Winnipeg, Manitoba
Fairfax County, Va.
Brunswick, Ga.
Tauton, Mass.
Morgantown, N.C,,
Lebanon, Pa.
Fairbanks, Alaska
Speedway, Ind.
Deer Park, Tex.
Lewisville, Tex,,
Mahoning County, Ohio
Jacksonville, Fla.
Calabasas, Calif.
(Las Virgenes, M.W.D.)
Littleton, Colo.
Cincinnati, Ohio
Hamburg, N.Y.
Minneapolis, Minn.
Chaska, Minn.
Design
Flow
(mgd)
16
15
14
13
12
12
10
8.4
8
8
8
7.5
6
6
4
3.4
1.8
1.5
1.2
1
1
0.9
Type of Status
Dissolution (Oct. 1974)
System
Surface Aerators
Surface Aerators
Submerged Turbines
Surface Aerators
Surface Aerators
Surface Aerators
Surface Aerators
Surface Aerators
Surface Aerators
Surface Aerators
Undetermined
Surface Aerators
Surface Aerators
Surface Aerators
Surface Aerators
Surface Aerators
Converted Air
Diffusers
Surface Aerators
Surface Aerators
Surface Aerators
Fine- Bubble
Diffusers (Open Tank)
Surface Aerators
Const .
Design
Design
Const „
Oper.
Oper.
Oper.
Design
Const .
Design
Rebid
Oper.
Oper.
Const .
Const .
Startup
Oper.
Discontinued
Oper.
Const.
Oper.
Const .
Oper.
                               2,714.8
Treatment of Zimpro supernatant.
                                 354

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        TABLE  26.  INDUSTRIAL
                       PLANTS
WASTEWATER TREATMENT
UTILIZING OXYGEN
Plant
   Design
    Flow
   (mgd)
     Type of
   Dissolution
     System
  Status
(Oct. 1973)
1.  Container Corp.
    (Fernandina Beach, Fla.)
                    a
2.  Chesapeake Corp.
    (West Point, Va.)

3.  Gulf States Paper, Inc.a
    (Tuscaloosa, Ala.)

4.  Union Carbide Corp.
    (Sistersville, W. Va.)

5.  Uniori Carbide Corp.
    (Taft, La.)
                         Q
6.  American Cyanamid Co.
    (Pearl River, N.Y.)

7.  Standard Brands
    (Peeksville, N.Y.
                  b
8.  Hercules, Inc.
    (Wilmington, N.C.
     25
Surface Aerators
Const.
     16.3   Surface  Aerators     Oper.
     10
Surface Aerators    Startup
      4.3   Surface  Aerators    Oper.
      3.8   Submerged Turbines   Const,
      1.5   Surface  Aerators    Oper.
      1     Surface  Aerators    Oper.
            Surface  Aerators    Oper.
                                   62.9
 Pulp and Paper

 Petrochemical
 -»
 "Pharmaceutical

 Distillery
                                  355

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                               SUMMARY
1.  Oxygenation systems are equally applicable to new plant construction
    and upgrading of existing overloaded secondary treatment plants.
2.  Oxygenation systems should be designed as integrated packages consisting
    of a biological reactor,  a secondary clarifier, and sludge handling
    facilities.
3.  There are genuine indications that reduced excess biological sludge
    production is possible with Oxygenation;  however, additional verifying
    data are needed.
4.  Research and development  will continue on many areas of the total
    Oxygenation process to fully exploit the  potential of the process.
                                    356

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                             REFERENCES

"Continued Evaluation of Oxygen Use in Conventional Activated  Sludge
   Processing",  U.  S. Environmental Protection Agency, Water Pollution
   Control Research Series Report Number 17050 DNW 02/72, February  1972.
Dick,  R.  I.,  "Thickening" in Water Quality Improvement by Physical and
   Chemical Processes, Volume II, University of Texas Press, 1970.
Divet,  L., P.  Brouzes, and P. Pelzer, "Short Period Aeration Studies at
   Paris", presented at Annual Meeting of New York Water Pollution Control
   Association,  New York City, January  1963.
Duncan, J. and K. Hawata, "Evaluation of Sludge Thickening Theories",
   Journal Sanitary Engineering Division, ASCE, 94, Number SA2, April
   1968.
"Investigation of the Use of High Purity Oxygen Aeration in the Conventional
   Activated Sludge Process", U. S. Department of the Interior, Federal
   WaterQjality Administration, Water Pollution Control Research  Series
   Report Number 17050 DNW 05/70, May  1970.
Smith,  R. and R. G. Eilers, "A Generalized Computer Model for  Steady-State
   Performance of the Activated Sludge Process", U. S. Environmental Pro-
   tection Agency,  Water Pollution Control Research Series Report Number
   17090 ...  10/69, October  1969.
Stamberg, J.  B., D. F- Bishop, A. B. Hais, and S. M. Bennet, "System Al-
   ternatives in Oxygen Activated Sludge", presented at 45th Annual Water
   Pollution Control Federation Conference, Atlanta, October   1972.
                                    357

-------
                  AERATION SYSTEMS FOR METRO  CHICAGO
                 BART T. LYNAM, GENERAL  SUPERINTENDENT
        THE METROPOLITAN SANITARY DISTRICT  OF  GREATER CHICAGO
                          CHICAGO,  ILLINOIS
                               PRESENTED AT

        THIRD U.S./JAPAN CONFERENCE ON SEWAGE TREATMENT  TECHNOLOGY
                               TOKYO, JAPAN

                              FEBRUARY 1974
CO-AUTHORS:  STEVE GRAEF, SENIOR CIVIL ENGINEER
             DON WUNDERLICH, ASSOCIATE CIVIL ENGINEER
             THE METROPOLITAN SANITARY DISTRICT OF GREATER CHICAGO
                             CHICAGO,  ILLINOIS
                                   358

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                            ABSTRACT





               Aeration Systems for Metro Chicago









     The Metropolitan Sanitary District of Greater Chicago




has experimented with aeration system design and operation




since 1920-  Initial efforts involved full scale field



studies on activated sludge in advance of the design of the



three major treatment plants at North Side, Calumet and




West-Southwest.  Both diffused air and mechanical aeration




were extensively evaluated.  Evaluations included location




in tank, tank configuration, rate of oxygen transfer, diffuser



and aeration characteristics, and, finally, large scale oper-



ating problems.  The District's present aeration practice



evolved from this experimental program and many of the



practices developed are employed in plant designs throughout




the country.



     The flow diagram for a typical District facility would




include an air intake, primary and secondary air filters,



centrifugal or positive displacement blowers, air transport




system and porous diffuser plates located in the base of



each aeration tank to provide a spiral flow regime.  Sizes



and quantities are presented for the District's design and



operating practices and reference is made to detailed studies




which led to the present technology.
                              359

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                            CONTENTS

                                                              Page

 I.   Introduction                                             362

       A.   Services and Area
       B.   Quantities Treated
       C.   Plants - sizes,  types of aeration


II.   Development of Aeration Technology at the District       364

       A.   Early Years                                        364

           1.   Founding and Reversal
           2.   Design for natural stream assimilation

       B.   Experimentation with Secondary Treatment           364

           1.   DesPlaines River and Calumet Plants
           2.   Design and Operational parameters investigated

       C.   First Major Plant Design - Criteria                365

       D.   Diffuser Plate Studies                             366

           1.   Permeability
           2.   Uniformity
           3.   Diffuser plate rating

       E.   Second Major Plant Design                          367

           1.   Criteria
           2.   Clogging problems
       F.   Operational Life of Diffuser Plates

           1.   Problems at major plants
           2.   Identification of particulate clogging
           3.   Filter testing

       G.   Evolved Aeration System for West-Southwest

           1.   Increased permeability
           2.   Improved filtration
           3.   Reduced air flow per diffuser plate
           4.   Cost effective treatment
                             360
                                                              368
369

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 II.   (Cont'd)                                         Page
        H.  Recent Work with Aeration                  371

            1.   Instream aeration
            2.   Basin aeration
            3.   Small plant design and modification
            4.   Salt Creek plant design

III.   Fine Bubble Aeration Practice                    375

        A.  Introduction                               375

        B.  Intakes                                    375

            1.   Location
            2.   Blending for temperature control

        C.  Filters                                    377

            1.   Types
            2.   Function of dual system
            3.   Filtered air quality
            4.   Monitoring

        D.  Blowers                                    379

            1.   Types
            2.   Operating characteristics
            3.   Noise abatement

        E.  Air Mains                                  381

            1.   Sizes
            2.   Location
            3.   Protection
            4.   Couplings and valves

        F.  Aeration Tanks                             383

            1.   Configuration
            2.   Diffuser placement
            3.   Spiral flow
            4.   Diffuser specifications
            5.   Clogging and rejuvenation
            6.   Plate aeration capacity

        G.  Other Uses of Low Pressure Air


 IV.   Summary                                          391
                         361

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           Aeration Systems for Metro Chicago


                     Bart T. Lynam*



                      Introduction


     The Metropolitan Sanitary District of Greater Chicago

provides wastewater treatment, water pollution control and

flood protection services to an area comprising 860 square

miles, including the City of Chicago and approximately 120

suburbs.  Approximately 5.5 million people reside within the

service area,  which includes an industrial community contri-

buting a wastewater discharge equivalent to 4.5 million

additional persons.


     Three major wastewater treatment works handle the

bulk of the District's wastewater flow.  The West-Southwest,

North Side and Calumet Plants provided secondary treatment

to 875, 350, and 200 MGD respectively in 1972.  Each of these

plants employ activated sludge treatment with fine-bubble

aeration.  The District also operates four additional plants

in the 1 to 6 MGD range.  Two of the plants employ fine-

bubble aeration for secondary treatment while the others

incorporate mechanical aeration.
     *General Superintendent, The Metropolitan Sanitary
      District of Greater Chicago; Chicago, Illinois 60611
                             362

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     It should also be noted that the District is anti-




cipating the start-up of its 30 MGD Salt Creek Water




Reclamation Plant in early 1975.  This highly instru-




mented facility with computer assisted control will also




provide fine-bubble aeration to a two-stage activated




sludge process for nitrification.
                            363

-------
    Development of Aeration Technology at the District







Early Years






     When the Metropolitan Sanitary District was founded in




1889 its primary function was to prevent the pollution of




Lake Michigan and the city's water supply.  The Chicago river




(which originally carried sewage wastes into the lake) was




reversed and substantial quantities of lake water (up to 10,000




cfs) were diverted into the Illinois River Basin for dilution.




Design and operation criteria was based upon the need for




natural stream assimilation capacity for a population equiva-




lent to 3,000,000 anticipated around 1920.  Around 1910 the




District initiated treatment plant studies in anticipation of




the eventual population growth.







Experimentation with Secondary Treatment







     Recognizing that natural stream assimilation was a temporary




measure for a service area undergoing accelerated growth the




District incorporated facilities for experimentally testing




secondary treatment in the designs for the Des Plaines River




and the original Calumet sewage treatment plants.  Both went




into operation in 1922.
                              364

-------
The Des Plaines River plant incorporated full-scale activated




sludge treatment while the original .Calumet plant provided




Imhoff treatment with a portion of the flow passing through




full scale experimental activated sludge units.







     Studies performed during the late 1920's at these plants




included plain aeration, tapered aeration and sludge reaera-




tion.  Diffused aeration, mechanical aeration and various




combinations of the two were evaluated.  By the beginning of




the 1930's the effect of process design and operational para-




meters, such as tank depth, residence time, return sludge rates,




air flow rates per unit volume, and both spiral flow and




ridge-and-furrow flow, had been investigated.







First Major Plant Design







     The research activity at Des Plaines River and the original




Calumet Plants resulted in the 175 MOD North Side Activated




Sludge Plant which was placed in operation late in 1928.  The




design consisted of 36 diffused air, spiral flow aeration tanks




providing a 6.3 hour detention time with 20% return sludge.







     Two parallel rows of air diffuser plates were set in con-




crete holders at a depth of 15 feet.  These diffusers were




fabricated with a permeability ranging between 11.7 and 18.5.
                              365

-------
Permeability is essentially defined as the air discharge in




cfm passing a one-foot-square plate under a pressure of two




inches of water.  It should be noted that 18.5 was the highest




permeability manufactured at that time.  A plate ratio




(surface area of plates/surface area of aeration tank) of




9.6% was employed.  Compressed air was supplied to .the system




by 7 Turbo-Blowers having a combined capacity of 250,000 cfm




at 7.75 psig.  Oil-coated impingement filters were used to




filter the incoming air.







Diffuser Plate Studies







     An ongoing battery of diffuser tests were initiated




shortly after the North Side start-up to provide an economic




design for the proposed addition at Calumet and the new Southwest




plant.  These studies by Beck (1)  investigated the effects of




permeability and plate thickness on air rates, bubble size,




and pressure loss.   Efforts were aimed at reducing diffuser




plate pressure losses in order to keep the cost of compress-




ing air as low as possible.  It was soon recognized that




uniform air distribution through the diffuser plates was needed




to avoid operational problems.  Later it was found that plates




with higher permeability gave better uniformity with only a




slight reduction in bubble area per unit of air.
                              366

-------
The studies also disclosed that lower pressure losses and




reduced plate clogging, resulting in longer life, could be




attained by operating the system with lov/er individual




plate air rates.  Perhaps, the most significant result of




these early diffuser tests by Beck was the formulation of




an accurate method for rating diffuser plates.







Second Major Plant Design







     Based on the success of the system at North Side, a new




136 MGD activated sludge plant was placed in service at Calumet




in 1935.  The design for Calumet was similar to the North Side




design except that the specifications called for diffuser plates




with a higher permeability range (36 to 44).  Contrary to the




North Side experience, operations at Calumet were seriously




handicapped by diffuser clogging due to industrial wastes




containing suspended and dissolved iron compounds.  These




materials precipitated in the aeration tanks resulting in ferric




oxide which clogged the upper faces of the diffuser plates.  The




clogging persisted for years.  Extensive tests were made on raw




sewage composition, diffuser properties and cleaning techniques.




The problem was eventually solved by prohibiting discharge of




pickled liquor into the sewer system and by increasing the




air discharge rate through the diffusers to keep the particulate




matter in suspension.
                              367

-------
Operational Life of Diffuser Plates







     By 1940 the Activated Sludge process was in service at the




West-Southwest Plant in addition to North Side and Calumet.




While iron deposits were hindering the Calumet Plant, diffuser




clogging problems developed at West-Southwest.  As a result,




air distribution studies were initiated (2)  at all of the




District's major plants to determine what steps could be taken




to extend the operational life of the diffuser plates.







     The original diffuser plates installed at West-Southwest




were replaced with plates of 80 permeability in 1945.  By 1947




the pressure losses had again become excessive.  Tests revealed




that the plates clogged primarily from dust in the air supply.




The air supply was particularly dirty in the area of the




West-Southwest Plant due to soot from the coal-fired boilers.




Unfiltered air contained as much as 9 mg of particulate/1,000




cubic feet.  Filtered air from the original impingement air




filters contained 3.5 mg/1,000 cubic feet.  Many different fil-




ters and secondary filters were tested in order to reduce the




dust content.







     It was decided to replace the old impingement filters with




Electro-Matic Filters in which unfiltered air passes through



an electrostatic field.
                              368

-------
Charged dust particles are then  attracted by oppositely




charged plates covered with an oil film, where they are




ultimately captured.  These filters were successful in




reducing the dust content of the air to 1 nig/1,000 cubic




feet.  Early operation, however, pointed out the need to




temper  outside air in colder weather to prevent icing on




the filters.  Furthermore, the initial operation indicated




that the 1 mg/1,000 cubic feet was still excessive.






     By 1948 tests concluded that precoated bag filters




should be installed at Southwest to reduce the dust in the




filtered air to less than 0.1 mg/1,000 cubic feet.  Addi-




tionally, the bag filter was simple to operate and maintain,




had a low pressure loss across the filter, and was not




adversely affected by inclement weather conditions.  As a




result it was decided to employ the bag filters as the




primary filtering system and to utilize the Electro-Matic




filters as a secondary system.






Evolved Aeration System at West-Southwest






     In the design for the third activated sludge battery at




West-Southwest an economical air diffusion system had evolved
                             369

-------
consisting of bag filters and diffuser plates with an




80-permeability rating utilizing a comparatively low




air rate per plate.  The low plate air rates required




additional plates and hence a higher first cost.  Yet by




comparison the modified operating procedure was cost




effective based on reduced maintenance costs and longer




plate life.  An exhaustive economic comparison was made




for various types of diffusers (plates, jets, and tubes).




The findings resulted in a system consisting of 1 inch




thick porous ceramic plates similar to the replacement




plates added to batteries A and B in 1945.  The major




change coming out of this study was the placing of the




diffuser plates normal to the walls with 20% to 30%




additional plates in the influent half of the tanks.  When




this change was considered with the improved air filtering




the District's engineers anticipated that the plates would




have a useful life of 14 years.  Battery C was put in




operation in 1950 and the original plates are still operat-




ing satisfactory today.







     The excellent operation of Battery C resulted in the




design of this system becoming the standard for the activated




sludge process within the District.
                           370

-------
The ease of operation, minimal maintenance required, and




excellent performance resulted in its adoption as the




aeration system for large plants.







Recent Work with Aeration







     In addition to the design of a fourth activated sludge




battery at West-Southwest, the District has engaged in




aeration studies and applications in the following areas:




stream aeration, basin aeration, small plant design and




modification, and the Salt Creek plant design.






     In order to meet regulations set by the IPCB requiring




that certain set dissolved oxygen concentrations be main-




tained in the waterways system, the District considered a




variety of in-stream aeration designs.  The objective was to




artificially aerate the low points on the oxygen sag curve




along the District's Waterway system.  Mechanical, diffused




air and pureoxygen aeration equipment was studied, sized




and evaluated.  The design life was estimated at ten years




since it is anticipated that the proposed Chicago Underflow




Plan and major plant expansion to tertiary treatment would




render the project obsolete.
                            371

-------
The Chicago Underflow Plan (which would capture and treat




the stormwater run-off from Chicago by utilizing temporary




underground storage in tunnels and surface storage in




abandoned rock quarries with gradual pump back to the major




plants for complete treatment during dry weather)  together




with the tertiary treatment of all wastewater from the




District's service area would insure adequate D.O. levels




in the waterways without the need for in-stream aeration.




An economic comparison indicated that total costs per pound




of oxygen transferred were lowest for floating mechanical




aerators primarily because of a lower capital cost.  Unfor-




tunately the narrow width of the channel precluded the design




because of its potential navigational hinderance.   A scheme,




whereby a portion of the stream would be withdrawn into a




pure oxygen aeration system and then reintroduced to the




stream was evaluated.  Although the entire system could be




placed on shore out of the way of navigation, the total cost




(per pound of oxygen added) was slightly higher and was thus




passed over.  Diffused aeration with porous diffusers was




ultimately selected because of its location in the channel




floor, out of the way of barge traffic.  Its total cost




fell between that for mechanical aeration and pure oxygen




aeration.
                              372

-------
District experience with aeration basin design and opera-




tion has been almost exclusively with mechanical aeration.




For the most part, these aerators have had low capital costs,




been easy to install and operate and are best suited for the




relatively short design life of aeration basins.







     In recent years the District has extended service to




several remote areas which were struggling to provide treat-




ment for their wastewater.  In the course of expansion,




several small, overloaded plants were obtained by the District




through annexation.  It was decided to employ mechanical




aeration at two facilities because of their relatively short




life spans in view of existing phase out schedules.  In both




instances improved treatment of the existing trickling filter




plants required conversion to the activated sludge process. The




existing circular trickling filters made it more economical




and easier (as well as quicker) to install surface mechanical




aerators.







     Most recently the District has undertaken the design and




construction of a highly instrumented, two stage activated




sludge Water Reclamation Plant at Salt Creek.  Since the size




(30, expansible to 125 MGD) was on the border line between a




large and small plant, an economic comparison was made between
                              373

-------
mechanical and diffused air aeration.  Mechanical aeration




was slightly lower in total cost for the initial 30 MGD




size.  Both design concepts were then carefully reviewed.




Ultimately, diffused air was selected because of (1) its




econoroy in the light of anticipated plant expansion; (2) its




capability to provide step feed, contact stabilization, com-




plete mix and tapered  aeration, in addition to conventional




activated sludge treatment; and (3) its excellent past




performance and reliability.  This facility featuring com-




puter assisted operation is scheduled to go on .stream in




early 1975.
                            374

-------
             FINE BUBBLE AERATION PRACTICE







     Even though the equipment varies from plant to plant




aeration systems throughout the District are conceptually




similar.  Although there are several uses for low pressure




air within the plant, the primary use of the air is to




transfer oxygen to the activated sludge process and keep the




mixed liquor in suspension.  In a typical District design,




Figure 1, atmospheric air enters the system through an air




intake.  Air passes from the intake through primary and




secondary filters before being compressed by the blowers.




It then discharges into air mains and headers which trans-




port the pressurized air to porous plate diffusers in the




aeration tanks.







Intakes







     Air intakes are located to optimize the air quality




being drawn in and are usually equipped with louvers to




protect the air passages.  Atmospheric air passes through




the intake into a chamber leading to the first of a dual set




of filters.  Besides connecting the intake and the first set




of filters, the chamber also serves to blend warm building




exhaust air with atmospheric air in winter to maintain a




temperature  above freezing through the filters.  Without



such provision condensate could freeze in the filters.







                             375

-------
                                          OUTSIDE AIR INTAKE HOOD
                                                                                                        84" BLOWER DISCHARGE
CO
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                                                     FILTERED  AIR DUCT
                                           f    BLOWER
                                                SUCTION
                                                CHAMBER

                                      n     n
                                           AH

                                          INTAKE

                                          SHAFT
PRIMARY PRECOATED BAB FILTERS
                                                                 TO AERATION BATTERIES
                                                                                                             TO AERATION BATTERIES
          SECONDARY DRY MEDIUM FILTERS
                           AIR FLOW  DIAGRAM  AT WEST-SOUTHWEST PLANT  	(
                                                               AERATED GRIT CHAMBERS

                                                                         AIR LIFT PUMPS

                                                                       CONVEYANCE CONDUITS
                                                                                                                      FIGURE 1

-------
Filters







     Air filters are the most vulnerable link in the




aeration system's chain of processes.  Basically, there




are four types of filters which have been utilized over




the years.  These include viscous filters, dry medium




filters, electronic filters and precoated bag filters.







     The Metropolitan Sanitary District plants,  like most




plants practicing diffused aeration, employ a dual set of




air filters.  Primary filters remove most of the particu-




late matter.  Secondary or back-up filters provided addi-




tional removal of particulates which pass the primary and




protect against system damage, should the primary filters




rupture or fail.







     The primary filters at the West-Southwest plant are




the precoated bag type equipment.  Incoming air passes up




through the center of the bag and then outward through the




precoated material on the primary filter.  During normal




operation air passing the primary filters will contain




particulate matter in concentrations less than 0.05 mg per




1,000 cubic feet.  To insure good filtration the precoated




bags are cleaned every year.  One filter at a time is isolated




and then shaken rapidly, Figure 2, so as to remove the



precoat together with all accumulated dust.






                            377

-------
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                                  DUST TUBE SECTION

-------
The used precoat and dust falls into a hopper at the bottom of




the filter unit and is removed.  The bags are then recharged




and the unit is returned to service.  It is important to




note that the absolute concentration leaving the filter is




far more important than the percent removal by the filter.




Filtered air quality is determined by drawing 50,000 cubic




feet of filtered air throxigh a tared sample thimble.






     The secondary filters at the West-Southwest plant are of




the dry medium type and have the shape of a large sock or




mitten.  These provide back-up and help to insure a long




service life before cleaning and rejuvenation of the .aeration




system is needed.  Furthermore  filter equipment is over-




designed in comparison to the blowers, since they comprise




the critical stage in an aeration system; they are designed




so that all blowers can be placed in service with one filter




unit out of service.  An important part of filter operation




is a careful monitoring program.  Important parameters include




time in service, pressure drop across the filters, air volume




filtered, air flow rate, and particulate concentration of the




effluent.






Blowers





     Filtered air makes its way through butterfly doors into



a  common air tunnel which feeds the plant blowers.
                             379

-------
The District employs several types of blowers including




vane axial, centrifugal and positive displacement varie-




ties.  The new Salt Creek Water Reclamation Plant will




have a new type of blower which will permit a broader




range of operating capability because of its automatic




inlet guide vane control.   The District's blowers range




in size from 1,500 cubic  feet per minute up to 200,000




cubic feet per minute. These blowers are powered by




several types of prime movers including steam turbines,




electric motors and gas turbines.  Blowers, which are




essentially low pressure  compressors, produce an output




pressure between 7.5 and  10 psi.  Since the friction




losses are in the order of 0.5 to 2.5 psi most of the blower




output pressure is needed to overcome the 15 to 17 feet




of hydrostatic head.  Inherent in blower operation is




a substantial temperature increase in the air.  For




example, with a blower discharge pressure of 8 psi the




air temperature rise would be approximately 100°F above




ambient temperature.







     An important factor  in the design and installation




of blower systems is noise reduction.  Silencers are




installed in the air piping to maintain sound levels




within a reasonable range.
                            380

-------
In order to minimize noise on the largest blower at the




West-Southwest plant, an acoustical housing was fabricated




to enclose both the turbine and the blower.  The insula-




tion consisted of three (3) inches of fiberglass material.






Air Mains







     The discharge from the blowers is transported through




large air mains to the aeration tanks with small quantities




being routed to other processes such as aerated grit chambers




and air lift pumps.  This air transport system consists of




piping ranging from 84-inch conduits to 4-inch diffuser header




pipes.  Much of the piping is contained in service tunnels




and galleries, thus enabling workmen to inspect and service




them readily.






     The general requirements for air piping are as follows:




(a) the outside of the pipe must be sufficiently corrosion




resistant for the location and (b) the inside of the pipe must




remain so clean and sound that it will not give off any




particles which would add to the clogging of the diffusers.




Procedures have been developed for protecting air piping




against corrosion and pitting.  Large piping over 24 inches,




which is located inside buildings, galleries, or embedded



in concrete, is steel with the outside painted and inside bare
                             381

-------
The inside receives a grease coating during construction




and is washed clean with solvents before being placed in




operation.  Smaller pipe, 8 to 24 inches, is spiral




galvanized steel.  Piping 6 inches and under is standard




weight galvanized steel.  Other piping which is submerged




or immediately above wastewater is galvanized cast iron




when 3 inches or larger.






     These precautions are necessary for the following




reasons.  Air comes from the blowers at about 100°F above




the atmospheric temperature, and as long as it remains a




few degrees above the atmosphere there is no condensation




to cause rusting.  Therefore, no protective coating is




necessary for mains inside the buildings and galleries after




they are put in service.  However, pipes too small for men




to enter for thorough cleaning just prior to placing in




service are galvanized to insure a clean interior.




Bituminous coatings and paints are not used for interior




coatings because oxidation of the coating or paint vehicle




releases particles which contribute to diffuser clogging.






     Where pipes are submerged, condensation will occur




at times inside the pipes, due to the lowered temperatures,




and this requires a good coating to prevent rusting.
                            382

-------
Also, the outside of submerged pipes is subjected to




corrosive conditions which are somewhat unpredictable.







     Important factors in pipeline design are the types




of couplings and joints.  These must be capable of




handling the velocities and temperature of the air flow.




Extensive use of valving is incorporated in the system




for both controlling and isolating air flow.  Automatic




and manually operated valves have been employed.  The




District's new Salt Creek Water Reclamation plant will




have the capability of automatic air rate control.  Dis-




solved oxygen sensors will regulate the automatic control




valves which distribute air into the aeration tanks.




Large diameter air mains at the District's major plants




are usually fitted with butterfly valves, while the small




diameter conduits consist of globe valves.  An important




function in operating the air transport system is the care-




ful monitoring of air pressures and flows.







Aeration Tanks







     Most of the aeration tanks, Figure 3, within the




Metropolitan Sanitary District consist of long, multipass




concrete channels having rectangular cross sections.
                           383

-------
                                                                                         (SEE FIGURE 4 FOR SECTIONAL VIEW).
GO
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                                                                              4i8-
                           L.   r 4 NON-PRESSURE WALL
                                                                 6- AIR HEADER


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                                      . 6" AR  PIPING UP TO 18" HEADER (TYPICAL)
                            I
                                                                      DIFFUSER PLATE HOLDERS
                                                                            
-------
Porous plates tightly cemented in durable, solid concrete




plate holders are placed (six plates/holder)  along one




of the channel walls.  .Because of its effective air fil-




tration equipment, the District has been able to economize




by setting diffuser plates with mortar rather than remov-




able metal plate holders.  A header pipe connects the air




main and the porous plate diffusers, Figure 4, thus permitt-




ing distribution of air into the base of the aeration tanks.




Since the diffusers are constructed adjacent to one of the




channel walls. Figure 5, a spiral or overturning flow




regime is established by the air distribution.  As a result,




two benefits accrue.  One air main serves two channels and




the spiral flow insures that the solids will remain in




suspension.  King (3) reported results of an extensive study




of tank velocities at various horizontal and vertical loca-




tions.







     Years of District experience with diffuser plates




have led to well defined specifications for these diffuser




plates.  The plates are approximately 12" square and 1"




thick.  The fabrication materials may be either a crystal




aluminum oxide bounded with a high alumina glass or a sili-




cious sand bonded with silicate.  Rigid permeability (2)



and oxygen absorption rating (3,4) requirements must be
                            385

-------
                               6" ANGLE VALVE
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                                                                                   6" ANGLE VALVE
L__ 4 DRAINAGE TRENCH
                                                                      NON-PRESSURE WALL
                                                   TYPICAL AERATION  TANK
                                                        CROSS SECTION
                                                                                                              FIGURE 4

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                                                                                                            AIR MAIN
CO
00
                     TYPICAL INTERIOR NON-PRESSURE WALL WITHOUT AIR MAIN
                                                                          (£ TYPICAL INTERIOR NON-PRESSURE WALL WITH AIP MAIN
                                        TYPICAL CROSS SECTION OF SPIRAL FLOW  AERATION TANK
                                                                                                                            FIGURE 5

-------
met as determined by specific empirical techniques.







     After installation, pressure loss and volume of air




diffused are monitored closely.  From time to time, the




air rate is temporarily raised and lowered  to enable a




plot of pressure loss versus flow rate.  A pronounced




upward curve is an indication that the plates are clogging.




Clogging can occur on the air side or the liquor side.




Except for the ferric oxide deposits at the Calumet plant,




most clogging has occurred on the air side.  Besides




particulate problems, some pressure loss has occurred from




condensation in diffuser headers during the early spring




and summer.  Two methods have been employed for rejuvenat-




ing the plates.  The most effective has been removal and




kiln burning.  The second, a temporary measure, is washing




the plates with an acid.






     Recent District designs provide more than adequate




mixing velocities.  This is insured by plate arrangements




which discharge 8 to 12 cfm of air per foot of tank length.




Several plates are placed side by side in rows to provide




a band of aeration between 6 and 12 feet in width.  In the




past, fewer plates were placed in the effluent half of the




aeration tanks to produce a tapered aeration effect.
                           388

-------
This served well in the conventional activated sludge




process.  The District now provides step feed capabili-




ties in its designs so a uniform plate area is provided




throughout the aeration tanks.  The nominal distribution




capacity of an individual diffuser plate ranges from




1 to 4 cfm.  MSD experience has demonstrated that a long




service life can be obtained from the porous plates if




adequate air filtration and careful placement of the




plates are practiced.






Other Uses of Low Pressure Air






     The aerated grit chambers in the District plants




utilize air drawn from the blower system.  This air is




diffused into the wastewater stream through submerged non-




porous diffusers located close to the bottom of the chamber,




The quantity of air used by the aerated grit chambers




ranges from 2% to 5 percent of the total blower output.




Another important use of low pressure air is the air lift




pumps serving the final clarifiers, primary settling tanks




and concentration tanks.  The quantity utilized in these




locations ranges from twelve to twenty percent of the




total blower output.
                            389

-------
     Low pressure air is also used in minor quantities




for aerating and mixing various wastewater conveyance




conduits.  Moreover,  it is utilized for post aeration




at the Hanover Park Water Reclamation Plant and the Salt




Creek Water Reclamation Plant.
                           390

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                         SUMMARY







     The Metropolitan Sanitary District of Greater Chicago




has been engaged in aeration systems development since 1920,




Its principal contributions have been in diffuser perme-




ability criteria, design and operation of primary .and




secondary air filters, aeration tank configuration and




diffuser placement and the formulation of mathematical rela-




tionships for oxygen transfer.  The result has been an




effective economical technology for the activated sludge




process.
                            391

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                    REFERENCES
.1.   Beck, A. J., "Diffuser Plate Studies" Sewage
     Works Journal, 8, 1, pg. 22 (1936)
2.   Anderson, N. E., "Tests and Studies on Air
     Diffusers for Activated Sludge",  Sewage Works
     Journal,  22, 4, pg. 461 (1950)
3.   King, H. R., "Mechanics of Oxygen Absorption in
     Spiral Flow Aeration Tanks.  I. Derivation of
     Formulas", Sewage and Industrial Wastes Journal,
     22, 8, pg. 894 (1955)
4.   King, H. R., "Mechanics of Oxygen Absorption in
     Spiral Flow Aeration Tanks.  II. Experimental
     Work", Sewage and Industrial Waste Journal, 27,
     9, pg. 1007 (1955)
5.   Water Pollution Control Federation "Manual of
     Practice No. 5 Aeration in Wastewater Treatment1
     Published by WPCF, Washington D.C., 1971
                          392

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                OXYGEN ACTIVATED SLUDGE SYSTEMS IN TEXAS
                 DICK WHITTINGTON,  P.E., DEPUTY DIRECTOR
                        TEXAS WATER QUALITY BOA.RD
                              AUSTIN, TEXAS
                              PRESENTED AT

      THIRD U.S./JAPAN CONFERENCE ON SEWAGE TREATMENT TECHNOLOGY
                              TOKYO,  JAPAN


                              FEBRUARY 1974
CO-AUTHOR: TIMOTHY B. TISCHLER,  TEXAS  WATER QUALITY BOARD, AUSTIN, TEXAS
                                  393

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                 OXYGEN ACTIVATED SLUDGE SYSTEMS IN TEXAS








               REVIEW OF OXYGEN USE IN WASTEWATER TREATMENT





       Since D. A. Okun's first experiments with the Bio-Precipitation, a




pure oxygen process, in the late 1940's, the use of high purity oxygen in




wastewater treatment has created surges of interest followed by periods of




diminished interest in the academic community and in industry.  These early




studies were conducted on laboratory scale and on pilot plant scale during




the 1950's.  The pilot plant sutdies on municipal sewage concluded that the




use of pure oxygen resulted in a savings in reactor volume and total plant




area.  These savings were due to the greater concentration of mixed-liquor




solids that can be maintained aerobic with oxygen.  The power requirements




of the conventional system and the Bio-Precipitation process were found to




be essentially equal.  In order for the Bio-Precipitation process to offer




an economic advantage, the cost savings resulting from the decreased size of




the reactor had to be greater than the additional costs associated with pro-




viding high purity oxygen.  Evidently, the advantages were not sufficient,




as further research into the use of pure oxygen was not significant for nearly




ten years.





       Interest in the use of pure oxygen was revived by the Linde Division




of Union Carbide Corporation in the late 1960's, when the Corporation began




seeking additional markets for its new oxygen production process.  The Union




Carbide process utilized a multi-stage, covered system which it named the




Unox Process.  This system was first evaluated at the Batavia, New York,




municipal sewage treatment plant where it was operated in parallel with a







                                    394

-------
conventional activated sludge plant.'^'  Since that initial investigation,




the applicability of the process to a wide range of wastewater characteristics




has been demonstrated by pilot plant studies throughout the United States. ^







                             THE UNOX PROCESS




       The only significant application of pure oxygen to waste treatment




available today is the Unox Process.  In the Unox Process, oxygen absorption




takes place within the mixed-liquor of the biological reactor.  The system




utilizes a series of gas-liquid contacting units or cells.  Mass transfer




and mixing within the cells is accomplished with a surface aerator or a




sparged-turbine system.  The individual cells are gas-tight, allowing the




atmosphere in each cell to be collected and diffused into each succeeding




cell.  High purity oxygen is added to the first cell, thus providing maximum




dissolved oxygen concentrations in the first cell where the oxygen demand is




greatest.  At the end of the series of cells, the remaining gas, containing




a small fraction of the initial oxygen content, is vented to the atmosphere.




Liquid-solids separation is accomplished in conventional clarifiers.






                        THE UNOX PROCESS IN TEXAS




       There are presently no large-scale Unox systems in operation or




under design in Texas.  Four small to medium size Unox systems are under




construction or are being planned by Texas municipalities.  A 6 MGD (22,800




m3/day) Unox plant is being built by the City of Deer Park.  This plant is




scheduled to begin operation in the early part of 1974.  Construction on




another 6 MGD (22,800 m3/day) plant for the City of Lewisville began in




January 1974.  Additional Unox installations are planned by Pasadena and




Missouri City, Texas.
                                   395

-------
       There is no plant performance data available for any of the Texas




Unox installations at this time.






                       REPORTED ADVANTAGES OF UNOX





       The reported advantages of the Unox Process include: reductions in




biological reactor volumes, higher oxygen-transfer efficiencies, improved




sludge handling characteristics, simplified process control and odor control.




       Reduction in the size of the biological reactors is accomplished by




the use of a much higher mixed-liquor solids concentration in the Unox




Process.  The higher concentration of biological solids can be maintained




in an aerobic condition by the greatly improved oxygen mass-transfer effi-




ciencies of pure oxygen.  The higher mixed-liquor solids concentration




allows the designer to decrease the biological reactor volume while main-




taining the system mass-loading rate at a level comparable to that of




conventional designs.  The savings realized from tankage reductions repre-




sents the main economic advantage of the oxygen system.






       The more direct advantages resulting from the higher oxygen-transfer




efficiencies of pure oxygen include equipment-size reductions and reduction




in power usage.  The lower equipment requirements of the oxygen system




produce a savings in a projects capital cost, and the reduced power consump-




tion a decrease in operating costs.





       Other reported advantages of oxygen are improved sludge settling




characteristics and a reduction in the quantity of waste solids produced.





       The greatly improved sludge settling characteristics of oxygenated




biological solids have been reported by a number of investigators.(3)  The




advantages of an improved settling sludge are twofold.  The improved clari-
                                     396

-------
fier-underflow concentration allows the maintenance of the high operating




mixed-liquor solids concentrations and the thicker clarifier underflow




results in considerable savings in sludge handling.





       The Union Carbide Corporation has reported a reduced sludge




production from their Unox Process and has attributed the decrease to a




highly aerobic sludge.  They have postulated that the high dissolved oxygen




concentration of the Unox Process is able to penetrate large floe particles,




thus maintaining the entire sludge mass aerobic and active.^  These results




have been contradicted by independent investigations conducted on bench-




scale-sized pure oxygen units.'3^  The results of these experiments indicate




the Kinetics of activated sludge systems operated at a dissolved oxygen




concentration as great as 20 mg/1 do not vary significantly from the reported




Kinetics of conventional systems.  Furthermore, studies of oxygen diffusion




through biological floe particles have shown that for dissolved oxygen con-




centrations and floe particle sizes normally encountered in the conventional




activated sludge process, the entire mass of the floe particle is aerobic.^ '




       The dispute over excess solids production should be conclusively




answered in the next several years as an inventory of operating data is




accumulated.





       The simplified process control of the Unox system also has its




advantages.  A simple pressure control system is used to monitor the oxygen




requirements of the system, thereby permitting only the oxygen needed to be




applied.  The system easily "tailors" the oxygen applied to the diurnal




demands of the wastewater.  A considerable savings in power is realized by




this integrated system.
                                     397

-------
       The enhanced ability of the Unox Process to respond quickly and




automatically to varying oxygen demands, thereby maintaining a minimum




dissolved oxygen concentration of 1-2 mg/1, and to maintain higher return




sludge solids concentrations should improve the stability of the process




and minimize plant upsets.  Should this be the case in actual plant




operations, the Unox Process would have a decided advantage over the




conventional activated sludge process.





       Another advantage -of the covered tank system is that effective odor




control of the vent gas can be practically achieved.  The total gas vented




from the system is reported to be about 1% of the gas vented from an air-




activated-sludge system.* '






                POSSIBLE DISADVANTAGES OF THE UNOX SYSTEM




       The Unox Process includes sophisticated mechanical and electrical




control systems that ordinary treatment plant operators may find difficult




to control and maintain.  It is a sad fact, but true, that many of the




treatment plant operators in the State of Texas and in other states are




undereducated and underpaid.  These personnel may not be capable of main-




taining the Unox Process even after extensive instruction.  Municipalities




located in the industrial-urban areas of the State, where there is a reservoir




of persons trained in the maintenance of instrumentation and complex machinery,




can more readily assume this risk.




       Another possible disadvantage of the Unox Process is the possibility




of volatile hydrocarbons entering the enclosed system which could lead to




a serious explosion.  This possibility has been recognized by Union Carbide




and a sensitive hydrocarbon monitoring device is installed in every Unox
                                     398

-------
unit sold.   When significant hydrocarbon concentrations are detected by the
sensing device, the tanks are automatically purged of oxygen with air.  Proper
maintenance of this monitoring device would seem to be mandatory.

                        FUTURE OF UNOX IN TEXAS
       The Unox Process seems to be a viable alternative to the conventional
activated sludge process.  Its greatest advantage seems to be the reduction
in tank volumes and land areas needed for treatment.  These advantages would
be of primary importance in the renovation and expansion of existing large
sewage treatment plants in densely populated areas.
       While the economic advantages of the Unox Process for large municipal
plants may be considerable, there may be no economic advantages for small
communities.  Small communities should carefully consider the economics of
the Unox Process as compared to conventional designs, with special attention
being given to the complexity of operation and the need for highly trained
operators.  In Texas, we are assuming a "wait and see" attitude before
reaching a decision on the merits of this process in actual operation.

                                REFERENCES
1.  Environmental Protection Agency, "Oxygen Activated-Sludge Wastewater
    Treatment Systems", Technology Transfer Publication, August 1973.
2.  Mueller, Boyle and Lightfoot, "Oxygen Diffusion Through a Pure Culture
    Floe of Zoogloea Ramigera", Proceedings of the 21st Purdue Industrial
    Waste Conference.
3.  Tischler, Timothy B., "Kinetics of the Pure Oxygen Activated Sludge
    Process", Masters Thesis, Department of Environmental Health Engineering,
    The University of Texas, Austin, 1973.
                                    399

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                        SUSPENDED SOLIDS REMOVAL

                   PROCESSES STUDIED AT METRO CHICAGO
                  BART T.  LYNAM,  GENERAL SUPERINTENDENT
        THE METROPOLITAN  SANITARY DISTRICT OG GREATER CHICAGO
                           CHICAGO, ILLINOIS
                             PRESENTED AT

     THIRD U.S./JAPAN  CONFERENCE ON SEWAGE TREATMENT TECHNOLOGY
                             TOKYO,  JAPAN

                             FEBRUARY  1974

CO-AUTHORS:  DAVID R.  ZENZ,  COORDINATOR OF RESEARCH
             CECIL LUE-HING, DIRECTOR,  RESEARCH AND DEVELOPMENT
             GEORGE R. RICHARDSON,  HEAD, WASTEWATER RESEARCH SECTION
             THE METROPOLITAN  SANITARY  DISTRICT OF GREATER CHICAGO
                             CHICAGO,  ILLINOIS

                                  400

-------
                      TABLE OF CONTENTS


                                                            Page

   LIST OP TABLES                                            402


   LIST OF FIGURES                                           403


I.  SUSPENDED SOLIDS REMOVAL PROCESSES STUDIED AT
   METRO CHICAGO                                             405

       A.  Background                                        405

       B.  Full-Scale Evaluation of Sand Filtration
           and Microstraining at Hanover Park                408

       C.  Pilot Plant Studies At Hanover Park-Evaluation
           of Three Sand Filtration Devices
             1.  The DeLaval Filter

             2.  The Neptune Microfloc Unit                  423

             3.  The Graver Filter                           424

             4.  Results and Conclusions                 428, 435

       D.  Evaluation of 15 MGD Micros trainer At The
           North Side Treatment Works Of MSDGC.              436

       E.  Summary Comparison Of Tests Results Of
           Filtration Devices Tested                         447
                               401

-------
                   LIST   Of   TABLES
Table 1.     Hanover Park Sand Filters % Backwash
Table 2.     Operation Of The DeLaval Filter At Various
             Hydraulic Loadings
Page

 417




 429
Table 3.     Operation Of The Neptune Microfloc Unit -
             Treatment Of Secondary Effluent
 430
Table 4.     Comparison Of Operating And Performance
             Parameters Of The Filtration Devices Tested
             By MSD.
 448
                               402

-------
    LIST
                           0 F
FIGURES
Figure 1.
Figure 2.
Figure 3.




Figure 4.


Figure 5.




Figure 6.




Figure 7.

Figure 8.

Figure 9.

Figure 10-


Figure 11.

Figure 12.


Figure 13.
Continuous Flow Sand Filter Suspended
Solids Removal At High Head Without  Co-
agulation

Continuous Flow Sand Filter Tertiary
Effluent Suspended Solids As A Function Of
Hydraulic Loading And Secondary Effluent
Suspended Solids Based On Regression of
y = 0.756X - 0.03X

Continuous Flow Sand Filter Tertiary
Effluent BOD As A Function Of Hydraulic
Loading And Secondary Effluent BOD Based On
Regression Of y = 0.906X - 0.012

Microstrainer-Suspended Solids Removal With
Idle Speed At 10% Of Maximum

Microstrainer-Tertiary Effluent Suspended
Solids As A Function Of Hydraulic Loading
And Secondary Effluent Suspended Solids
Based On Regression Of y = 0.739X - 0.011

Microstrainer-Tertiary Effluent BOD As A
Function Of Hydraulic Loading And Secondary
Effluent BOD Based On Regression y = 0.736X +
0.0006

Diagram Of The DeLaval Filter

Flow Diagram Of The Neptune Microfloc Unit

Diagram Of The Graver Filter

Suspended Solids Loadings And Removals For
The Graver Filter

Backwash Usage For The Graver Filter

Influent And Effluent Suspended Solids And
BOD For The Graver Filter

Cumulative Frequency Distribution Of Influent
Suspended Solids Loading To North Side Micro-
strainer
                                                              410
                                                              411
                             412
                             414
                             415
                             416

                             422

                             425

                             426


                             432

                             433


                             434



                             440
                  403

-------
                 LIST   OF   FIGURES
                           (Continued)
                                                             Page

Figure 14.   Cumulative Frequency Distribution Of Flow
             Thru North Side Microstrainer                    441

Figure 15.   Cumulative Frequency Distribution Of
             Suspended Solids in ^orth Side Microstrainer     442

Figure 16.   Cumulative Frequency Distribution Of BOD
             Concentrations In North Side Microstrainer       444

Figure 17.   Backwash Data For North Side Microstrainer       445
                               404

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   SUSPENDED SOLIDS REMOVAL PROCESSES STUDIED AT METRO CHICAGO

     The  Metropolitan Sanitary District of Greater Chicago was
created by the Illinois State Legislature in 1889, to protect
Chicago's Lake Michigan drinking water supply from pollution.
This action was deemed necessary because in 1885, a heavy storm
of more than six inches over the Chicago area in a two day period,
flushed the streets, catch basins and sewers into the rivers and,
subsequently, polluted the lake far beyond the intake cribs which
supplied  the city's drinking water.  As a result, approximately
12 percent of the city's population died from such waterborne
diseases  as cholera, typhoid and dysentery.
     The  initial treatment system consisted of reversing the flow
of the Chicago River by the construction of a man-made canal system,
so that it carried discharged polluted water away from the lake.
This system of treatment by dilution was the first step in pre-
venting raw sewage from entering Lake Michigan and providing a
minimum level of treatment.
     Although the reversal of the Chicago River solved the prob-
lem for Chicago, neighboring states on the great lakes protested
that the  District was draining the lake and sued the District to
prevent it from taking unlimited quantities of water from the lake.
As a result of the law suit, lake diversion was reduced from
10,000 to 3,000 cubic feet per second.  Therefore, controlling
locks were constructed at Wilmette Harbor, the mouth of the Chicago
River and the Calumet River.  These locks control the diversions
                                 405

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from Lake Michigan.



     The loss of diversion water and the constantly increasing



flows of the rapidly growing Chicago area required the building of



treatment plants to intercept and process the sewage flowing into



the canals in order to keep the rivers and waterways from becoming



overly polluted.  Research work initiated by the District in 1911



enhanced by urging of the Supreme Court dealing with the diversion



matter, commenced a second phase in the District's waste treat-



ment program.  The North Side plant, serving the northern portion



of the area, was completed in 1928 and expanded in 1937.  The



West-Southwest plant, the world's largest sewage treatment plant,



was placed in operation in 1939.  Together with the Calumet plant



these plants today treat over 1.3 billion gallons of sewage from



a population of about 6.0 million people and an equivalent of an



additional 4.5 million people from non domestic sources.



     The District recognizes, however, that today secondary



treatment cannot be considered to be the ultimate objective in



sewage treatment as it was in the past.  In addition, stricter



rules and regulations being imposed by the Illinois Pollution



Control Board (IPCB), makes it mandatory to discharge a higher



quality effluent relatively free of contaminants including organic



suspended solids.



     IPCB rules and regulations take on added significance to



the Sanitary district when one considers that, during periods of



low flow up to 99% of the flow in the sanitary district's man-



made controlled waterway system consists of MSDGC effluent.
                                406

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According to the newly adopted rule, section 404  (f)  (ii) , MSDGC



is subject to an effluent standard of 10 mg/1 of BOD5 and 12 mg/1



SS by December 13, 1977.  For these reason the District has been



actively engaged in studying advanced wastewater treatment pro-



cesses on pilot or full-scale operation since 1968.



     Because of the importance of effective suspended solids



removal to the production of high quality effluents, the MSDGC



has conducted extensive full scale and pilot studies in this



area.  This paper presents some of the Districts experiences



resulting from these studies.
                               407

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             FULL SCALE EVALUATION OF SAND FILTRATION
               AND MICROSTRAINING AT HANOVER PARK

INTRODUCTION
     The initial full-scale tertiary treatment studies  in  terms
of removal of solids were conducted at the Hanover Park Treatment
Plant in 1968.  This work has been reported in detail by Lynam
et al. 
     Two methods of physical separation or removal of suspended
solids were investigated, namely sand filtration using  the Hardinge
design rapid sand filter and microstraining using the Glenfield
and Kennedy microstrainerf  The Hardinge sand filter utilizes a
silica sand with an effective size of 0.51 mm and a uniformity
coefficient of 1.62.  These filters are continuously cleaned by
a traveling backwash mechanism so that no major down-time is
experienced during backwash procedures.   This unit permits about
90% of the filter bed to be in continuous operation, the re-
maining 10% being that portion being automatically backwashed by
the travelling backwash mechanism.
     Microstraining is a method of filtration in which  a stain-
less steel fabric is used as a filtering medium.  The microstrainer
used at Hanover Park has a drum 10 feet in diameter and 10 feet
long in which the fabric is mounted on the periphery of the re-
volving drum.  The untreated water flows into the drum  and radially
outward through the microfabric, leaving behind the suspended
solids removed by the fabric.  The solids on the inside are
carried upward, where a row of backwash jets flush them into a
(1)   Tertiary Treatment at  Metro Chicago  by Means  of Rapid Sand
     Filtration and Microstrainers

                                408

-------
hopper mounted on the hollow axle of the drum.  The drum ipeed



and backwash pressure are automatically controlled by headloss



across the drum.  The maximum headloss is 6 inches; drum speed



can vary from a minimum of 0.7 to a maximum of 4.3 rpm and corre-



spondingly, the backwash pressures vary from 20 to 55 psi.



     In the process of analyzing the large amounts of data



collected it was discovered that plots of many parameters yield



poor correlations and were not useful in evaluating the efficiency



of the tertiary treatment process.  However, a plot of suspended



solids removal versus suspended solids loading in terms of



Ibs/ft2/day yield a high degree of correlation.  Consequently,



this method of data presentation will be used to summarize the



Hanover Park Operations.



RESULTS - SAND FILTRATION



     The performance of the sand filter is shown in Figure 1.  The



regression equation is y = 0.756X - 0.034 with a correlation



coefficient of 0.922.  A family of curves may be constructed from



the regression equation of Figure 1^ to show a relationship between



tertiary effluent quality in terms of suspended solids and hy-



draulic loadings.  This family of curves (Figure 2), demonstrates



the relationship between hydraulic loading and solids loading.  The



dashed line shows both an upper limit of 6 gpm/ft2 for hydraulic



loading and a solids loading limit of 0.65 Ibs/ft2/day to produce



a tertiary suspended solids quality dependent upon the combination



of secondary effluent quality and hydraulic loading.  The same



analysis was applied in terms of effluent BOD and the family of
                               409

-------
                                 FIGURE   1
                   CONTINUOUS  FLOW SAND  FILTER
O
32
LU
OC
     0.5
     0.4
     0.3
     0.2
     0.1
              SUSPENDED SOLIDS REMOVAL AT HIGH HEAD WITHOUT COAGULATION
                  o.i
0.2
0.3
0.4
0.5
                                                                        O.6
                             S S LOADING (!bs/sq. ft:/day)

-------
                                 FIGURE  2
                  CONTINUOUS FLOW SAND FILTER
TERTIARY EFFLUENT SUSPENDED SOLIDS AS A FUNCTION OF HYDRAULIC LOADING AND SECONDARY EFFLUENT
          SUSPENDED SOLIDS HIGH HEAD BASED ON REGRESSION OF Y = 0.756X - 0.034
        10

         9

         a

         7

         6

         5

         4

         3

         2

         1
\30 mg/l SECONDARY EFFLUENT
                             HYDRAULIC LOADING fapa/sq. ft.)

-------
 0
o
C3
                                  FIGURE   3
                   CONTINUOUS FLOW SAND FILTER
             TERTIARY EFFLUENT BOD AS A FUNCTION OF HYDRAULIC LOADING AND
            SECONDARY EFFLUENT BOD BASED ON REGRESSION OF Y = 0.906X - 0.012
                    mg/I SECONDARY EFFLUENT
                          HYDRAULIC LOADING (gpm/sq. ft.)

-------
curves  developed is shown in Figure 3_.


MICROSTRAINER


     Microstrainer performance at 10 percent idle speed  (0.7-rpm)


is given in Figure £.  The regression equation is y = 0.739X - 0.011


with a  correlation coefficient of 0.922.  The suspended  solids


removal at 0.7-rpm was significantly greater than at a 20 percent


idle speed.  It is believed that the slower speed allowed a greater


build-up of solids at the surface of the microstrainer fabric thus


yielding improved filtration.  A family of curves, may be


constructed from Figure £ to show the relationship between tertiary


effluent suspended solids and hydraulic loading.  This family of


curves  is shown in Figure 5_.  The dashed line shows an upper limit


of 6.5  gpm/ft2 for the hydraulic loading and 0.88 Ibs/ft2/day for


the pounds loading.  A similar analysis was applied in terms of


BOD and a family of curves developed as presented in Figure 6_.


     When one evaluates the overall efficiency of a physical


separation process consideration must be given to the amounts


of treated water used to backwash the unit after the maximum head


is reached.  Table !_ presents backwash consumption for the sand


filter at flows of 1.0 through  6.0 gal/min/ft2.  The backwash


exceeded 0.5% only once and that was at the maximum hydraulic


loading.  The percent of treated water used in backwashing the

                                                                    2
microstrainer increased to approximately 3 percent at 3.8 gal/min/ft


hydraulic loading.
                                413

-------
                                  FIGURE   4

                               MICROSTRAINER


                SUSPENDED SOLIDS REMOVAL WITH IDLE SPEED AT 10% OF MAXIMUM
     O.8
 >.
 c
-a
     0.3
JT3
O

3E
»/»
     0.2
     0.1
              
-------
                     FIGURE 5  miCROSTRAINER
        TERTIARY EFFLUENT SUSPENDED SOLIDS AS A FUNCTION
OF HYDRAULIC LOADING AND SECONDARY EFFLUENT SUSPENDED SOLIDS
             BASED ON REGRESSION OF Y= 0.739X - 0.011
                  mg/l SECONDARY EFFLUENT
                         HYDRAULIC LOADING (gpm/sq. it.)

-------

fr—
      0
                                FIGURE   6
                            MICROSTRAINER
             TERTIARY EFFLUENT BOD AS A FUNCTION OF HYDRAULIC LOADING AND
          SECONDARY EFFLUENT BOD. BASED OH THE REGRESSION OF Y = 0.736X+0.006
U^OHHU


\
\
v
x
\
\
\
s



|^^^HQH13u







20- mg/l SECOt^


V. 15 mg/l
^^
v
^'^^

^*^




<»— «—=J

' 	 »*.










JDARY EFFLUENT




mg/l
—

•*• m*u








5 mg/l


















































































































                                       6
                                                            10
                           HYDRAULIC LOADING (gp.«n/sq.ft.)

-------
  METROPOLITAN  SANITARY  DISTRICT
        OF   GREATER   CHICAGO
                TABLE  1
HANOVER  PARK  SAND  FILTERS
           %  BACKWASH
 FLOW Gol/(Mln)(Sq Ft)       % BACKWASH
        1                   0.31
        1.5                  0.33
        2                   0.33
        2.5                  0.35
        3                   0.34
        3.5                  0.36
        4                   0.37
        4.5                  0.40
        5                   0.42
        5.5                  0.48
        6                   0.65
                  417

-------
CONCLUSIONS
     1.    The maximum suspended solids loading to the sand



           filter was 0.65 Ib/ft2/day.








     2.    The maximum hydraulic loading to the sand filter



           was 6 gpm/ft2.







     3.    With an influent of 18 mg/1 of BOD and suspended



           solids, an effluent quality of 2.5 and 5.5 mg/1



           respectively can be obtained by the Hardinge sand



           filter.







     4.    The maximum suspended solids loading to the



           microstrainer was 0,88 Ibs/ft2/day.








     5.    The maximum hydraulic loading to the microstrainer



           was 6.5 gpm/ft2.








     6.    With an influent of 18 mg/1 of BOD and suspended



           solids an effluent quality of 4.0 and 5.0 mg/1



           respectively can be obtained for the Glenfield-



           Kennedy unit.








     7.    The sand filter backwash consumption was generally



           less than 0.5%  up to the maximum flow, while the



           microstrainer reached 3% at the maximum flow.
                               418

-------
        PILOT PLANT STUDIES AT THE HANOVER PARK TREATMENT



         WORKS - EVALUATION OF 3 SAND FILTRATION DEVICES





INTRODUCTION



     Following the studies conducted at the Hanover Treatment



Works involving the use of the Hardinge continuous flow sand fil-



ter, it was the decision of the staff of the District that other



sand devices should be evaluated.  This was necessary because of



the large amount of funds which would be required to meet the 1977



Illinois S.S. and BOD criteria (30 day average not to exceed 12 mg/1



of S.S. and 10 mg/1 BOD) and the necessity to select a treatment



method which would yield the most cost effective solution to



achieving such criteria.



     The MSDGC decided 3 pilot sand filtration devices would be



run in parallel and that this would enable direct comparison of



these processes without accounting for differences in feed source.



     An experimental area was set aside in the existing Hanover



Tertiary treatment plant and three types of deep bed, high rate



sard filtration pilot plants were set up.  The three devices were



a DeLaval  upflow filler, a Neptune Microfloc mixed media filter



and a Graver dual media pressure filter.



     The objective of the program was to investigate the perfor-



mance of each unit.



     All of the units received a common influent, that is, second-



ary effluent from the Hanover Treatment Works.  Direct simul-



taneous comparisons of effluent quality and operational parameters



were therefore readily possible.
                                419

-------
     It should be noted here that all data presented is based upon


filter runs, that is, the sampling was so arranged that influent


and effluent samples were gathered between backwash cycles.  There-


fore influent and effluent analysis as well as filter loadings are


based upon filter runs which were usually not of a 24-hour duration.

                                               2
Loading and removal figures are given in Ibs/ft /filter run and


influent and effluent samples are not generally for 24-hour periods.


     Utilizing influent and effluent analysis as well as the load-


ing and removal values based upon 24-hour samples is justified


for the previously discussed full scale Hanover studies, because


both the Hardinge sand filter and the Glenfield-Kennedy Micro-


strainer backwash virtually continuously.  Attempting to orient


analysis of data upon runs for the microstrainer and Hardinge


filter is not theoretically possible while the Hardinge filter


backwashes .many times during a given 24-hour period.


     Orienting analysis of data upon filter run for the 3 pilot


sand filters is justified due to the batch nature of the 3 devices


undergoing study.  Loading and removal values based upon filter


runs yield the total Ibs of S.S. per square foot applied or re-


moved between backwashes and are more meaningful and correlatable


with other operational and performance criteria.  Samples gather-


ed during a filter run while often not actually occurring during


a calendar day should be comparable with samples composited on a


24-hour calendar day.


EXPERIMENTAL APPARATUS


     1.  The DeLaval Filter
                               420

-------
     The  filter used was manufactured by the DeLaval Separator


Company and was an "Upflo Immedium  filter Model OT-3".  The filter


vessel was approximately 3 feet in diameter and 13 feet deep.  The


filtering media was silica sand and gravel, with the filter bed


being approximately 7 feet deep.  The bed had an effective surface


area of 6.75 square feet and at a maximum flow rate of approximately

        2
6 gpm/ft  , the unit can filter about 58,000 gallons daily.


     As can been seen in Figure T_, the flow through the filter


was upward, with the influent entering the unit through a large


number of nozzles located in a distribution plate at the bottom of


the filter vessel.  The filter media consisted of four layers, with


two of the layers being gravel and two of the layers being sand.


The two gravel layers served as support for the sand layers, as


well as distributing the flow uniformly and thereby reducing short


circuiting.  The first gravel layer which was at the bottom, was


a 4 inch layer consisting of coarse gravel (1-1/4 to 1-1/2 inches).


The second layer of gravel was 10 inches thick and contained gra-


vel  (3/8  to 5/8 inches).  On top of the gravel layers was a 12


inch layer of coarse sand (2 to 3 mm).  The filter bed was held in


place by a grid, which was buried near the top of the 60 inch fine


sand layer.  This filter was designed to utilized the entire depth


of the filter for filtration and solids storage.


     The  backwash cycle was accomplished as follows:  initially


the filtration cycle was terminated when the head loss through the


filter reached a preset level, which was usually 14 psi.  With the


filtration cycle terminated, the backwash cycle was then initiated
                                421

-------
THE METROPOLITAN SANITARY DISTRICT OF GREATER CHICAGO
 SAND RETAINING GRID
    INFLUENT
        WASH
3ID_-\
\,

I
v
SANE
i
FLOW
SAND
)(
, i
-2mm)
i i .
2-3mm)
GRAVEL ( 3/8 -5/8a)
GRAVELd 1/4-1 \/2a)
\
N SYSTEM -
K/l
*,1VI
_A
N^3-
^~
N^l
                                        WASTE
                                        FILTRATE
AIR
TO DRAIN
                   FIGURE 7
         DIAGRAM OF THE DeLAVAL FILTER
                       422

-------
by first draining the filter bed.  The filter was then fluidized


by forcing air through the filter at low pressure ( 5 to 10 psi).


After 3 minutes of air flow, the filter was flushed with water at


a rate of about 10 - 13 gpm/ft2.  After approximately ten minutes


of flushing the bed was allowed to settle for five minutes, with


the largest particles settling to the bottom and the finer par-


ticles to the top.


     2.  The Neptune Microfloc Unit


     The unit used was manufactured by Neptune Microfloc  Inc. and


was a "Reclamate SWB-27A."  The principal tank was 5 feet square


and 6 feet deep, and was divided into three compartments: a floc-


culation  chamber, a settling chamber, and a. filter chamber.  The


settling chamber contained settling tubes and the filtering media


consisted of anthracite coal, silica sand, garnet, and gravel.


The filter bed was 5 feet deep and had a surface area of 4 square

                                                  ^
feet, and a maximum flow through rate of 10 gpm/ft  or about 58,000


gpd.  The backwash storage tank was approximately 5 feet in dia-


meter and 7 feet deep.  Flow through the filter was regulated by


an effluent pump and an effluent rate control valve which was


operated by a level transmitter positioned above the bed.


     The filtering media consisted of from top to bottom: a 30


inch layer of anthracite coal (1.2 to 1.3 mm), a 12 inch layer of


silica sand (0.8 to 0.9 mm), a 6 inch layer of garnet (0.4 to 0.8


mm), and a 3 inch layer of support gravel 1.5 to 2.0 inches, and


at the bottom the entire bed rests on a 12 inch layer of gravel


(1/2 to 2 inches).
                                423

-------
     As can be seen in Figure 8_ the "Reclamate SWB-27A" could be



operated in several different modes.  The complete flow pattern



included chemical addition followed by flocculation, settling, and



removal.  However as shown in Figure £ if chemical addition was not



desired, the flocculation and settling chambers could be bypassed.



Therefore, the appropriate mode of operation can be selected on the



basis of the quality of the influent wastewater, the nature of the



suspended solids, and degree of tertiary treatment desired within



the performance limits of the unit.  The studies noted in this



paper will only include those tests when the flow bypassed the



flocculation and settling chambers and no coagulants were Utilized.



     When the head loss through the unit increased to the setting



on the vacuum switch located between the filter and the effluent



pump, the backwash cycle was initiated.  As shown in Figure 8,



both the filter and the settling chamber were cleaned during the



backwash cycle.  The backwash flow was 20 gpm/ft2 and the volume



of water required for a backwash was approximately 650 gallons.



Settling after backwash restored .the anthracite coal, silica sand,



garnet and gravel layer to their proper positions in accordance



with their density differences.



     3.  The Graver Filter



     The filter manufactured by the Graver Water Conditioning



Company was a "Monoscour Filter," and the Wastewater was pumped



down and through the filter.  A diagram of the Graver filter is



shown, in Figure 9_.  The filter vessel was 22 inches in diameter



and 7 feet 6 inches in height.  The filtering media consisted of
                                424

-------
-P.
ro
en
                   THE METROPOLITAN SANITARY DISTRICT OF GREATER CHICAGO
                                   w
                            V.-)
                          H
                    H
CHEMICAL
 _EEE£L
                        FLQCCULATION
                           TANK
  TUBE
SETTLERS
                                    o
                                       FIGURE 8
                                                    *
                 MIXED
                 MEDIA
 FILTER
CHAMBER
                                                                         EFFLUENT
                                                                            BACKWASH
                      FLOW DIAGRAM OF THE NEPTUNE MICROFLOC UNIT

-------
     SANITARY DISTRICT QF GREATER CHICAGO
          BACKWASH
          STORAGE
            FLOW
         ANTHRACITE
            SAND
                              EFFLUENT
                                 INFLUENT
                      BACKWASH
         FIGURE 9
DIAGRAM OF THE GRAVER FILTER
             426

-------
anthracite coal and silica sand, with the filter bed being approx-



imately 3  feet deep.   The bed had an effective surface area of



2.65 square feet and at a maximum flow rate of 11.5 gpm/ft2 the



unit was capable of filtering about 43,000 gallons daily.  As shown



in Figure  £,  the backwash storage compartment (6 feet in diameter



and 5 feet in height)  was positioned directly above the filter



vessel.



     A combination of anthracite coal and silica sand were used



during the test period with the \size of the anthracite being 1.0



to 1.4 mm and the size of silica sand being 0.6 to 0.7 mm.



     As in the case of the other filters, the filtration cycle was



automatically stopped when the influent pressure to the filter



reached a preset level.  The backwash cycle begins with the bed



being initially drained.  After the bed was drained, the filter



bed was then air scoured for 5 minutes at a rate of 15 scfm at 5



psi.  Following the air scouring the filter bed was allowed to



settle for 6 minutes,  after which the filter bed was backwashed



for 5 minutes at a rate of about 15 gpm/ft2.  The total volume of



water used during backwash was about 200 gallons.  After back-



washing the filter bed, it was allowed to settle, with the sand



settling below the anthracite coal because of its greater density.
                                427

-------
RESULTS


       DeLaval Filter


     In Table 2 are contained results of the operation of the


DeLaval filter at three different flow rates.


     Generally speaking, as the loading increased so did backwash


frequency and volume.  Based uppn the data collected, it appears


that the unit is capable of treating loadings up to 1.24 lbs/ft2/


day with backwash rates of less than 4%.


     It also appears, from the data collected, that the DeLaval

                                                              2
filter is capable of handling hydraulic loadings of 4-5 gpm/ft


with the effluent solids being about 5 - 7 mg/1 and the effluent


BOD about 5 -.9 mg/1.


       Neptune Microfloc


     The results obtained for the Neptune Microfloc unit are


represented in Table _3.  The unit was tested at flow rates


of 2 and 5 gpm/ft .  An increase in hydraulic loading, as com-


pared to the DeLaval unit, caused a reduction in loading.  As one


would expect, backwash frequency and, therefore, backwash usage


 increased with increased hydraulic loading.  Effluent BOD and


S.S. were between 4 to 6 mg/1 and appeared to be independent of


hydraulic loading.  The Neptune Microfloc unit appears to be cap-


able of achieving excellent effluent quality  (less than 6 mg/1 of


S.S. and BOD) at hydraulic loadings of 4 gpm/ft  with backwash


volumes less than 3%.


       Graver Pressure Filter


     Figure 10_ presents data on loading and removals of the Graver
                              428

-------
     METROPOLITAN  SANITARY  DISTRICT
          OF  GREATER  CHICAGO
                 TABLE  2
OPERATION  OF  THE  DE-LAVAL
AT VARIOUS HYDRAULIC  LOADINGS

 HYDRAULIC LOADING, GPM/SQ FT   4     4.7     5
Influent S.S., mg/l
Effluent S.S., mg/l
S.S. Removal, %
Influent BOD, mg/l
Effluent BOD, mg/l
BOD Removal, %
Length of Filter Runs, Hrs
S.S. Loading, Ib/sq ft/filter run
S.S. Removal, Ib/sq ft/filter run
Backwash Usage, %
12
7
44
7
5
26
43.0
1.04
0.45
2.5
14
7
54
17
9
48
37.0
1.23
0.67
2.7
H^BB^K£
14
5
62
18
5
72
35.4
1.24
0.70
3.7
                   429

-------
II  3
HYDRAULIC LOADING , GP^/SQ FT
laflyent S,S., aig/l
If!!udntS.S.,mg/l
S.S. Removal, %
Influent BOD, mg/l
Effluent BOD, mg/l
BOD Removal, %
Length of Filter Run, hours
S.S. Loading, Ib/sq f J/filtsr run
S.S. Removal, Ib/sq ft/filter run
Backwash Usage, %
2
14
4
73
23
6
74
106.3
1.53
1.12
1.3
4
BMMMHU
16
4
73
25
4
85
27.2
0.86
0.64
2.5
430

-------
Pressure Filter at flow rates from 2.2 to 9.0 gpm/ft2.  In



general, loading and removal were closely grouped over the entire



range of flow rates.  The highest loading was achieved at a flow



rate of 9.0 gpm/ft  where 1.9 lbs/ft2 was achieved at that flow



rate.



    Figure 11 presents results for backwash requirements of the



Graver filter.  Clearly, backwash usage remained fairly constant



over the range of flow rates.  This would seem to correlate with



the loading values given above in that if the loadings per filter



run remain consistent, backwash usage should also be so.  In



general, backwash usage was low usually being less than 1% for all



flow rates tested.



    Figure 12 presents the effluent quality for the Graver filter.



In general, for all hydraulic loadings, effluent solids range from



5 to 10 mg/1 while effluent BOD values range from 6 to 8 mg/1.



Apparently, effluent quality remains independent of hydraulic and



S.S. loading.



    The Graver filter appears capable of handling hydraulic loads



of up to 9 gpm/ft2 and S.S. loadings up to 1.9 lbs/ft2 and achieve



effluent quality averaging about 6 mg/1 of S.S. and BOD.
                                431

-------
   THE  METROPOLITAN  SANITARY  DISTRICT   OF  GREATER  CHICAGO
                                  FIGURE   10
        SUSPENDED  SOLIDS LOADINGS  AND  REMOVALS FOR  THE  GRAVER FILTER
       2.0-1
       1.5-
       1.0
       0.5
U>
                                   S.S. LOADIN

                                   S.S. REMOVAL
            2.2 gpm/ft2    4.O gpm/ft*    5.9gpm/ft3    6.0 gpm/ft2   «.0 gpm/ft3    9.O gpm/ft*

-------
             THE   METROPOLITAN  SANITARY  DISTRICT  OF  GREATER  CHICAGO
                                           FIGURE   11
                              BACKWASH  USAGE  FOR THE GRAVER  FILTER
GO
CO
                2.01
                 1.5*
                1.0
                                                           1.14%
                                               0.84%
                        0.65%
0.62%
                                                                      0.51%
                                                                                 0.44%
                      2.2 gpm/fta    4.0 gpm/f»a    5.9 gpm/f»a    6.0 gpm/fta    8,0 gpm/fta    9.O gpm/ft1

-------
            THE  METROPOLITAN  SAHITMY  DISTRICT  OF  GUiMift
                                            FIGURE  12
             INFLUENT  AND EFFLUENT  SUSPENDED  SOLIDS  AND B.O.D.  FOR THE  GRAVER  FILTER
CO
            O»
            E
           O
            •
           ca
           VI
           "O
            4>
               25
               20
                15
                10
                                                                    INFLUENT
                                                                    EFFLUENT
                     SS    BOD
                     2.2 gpm/f»a
 SS   BOD
4.0 gmp/ft
SS   BOD
5.9 gpm/ft *
SS   BOD
6.0 gpn/ft a
SS
BOD
SS
                BOD
8.0 gpm/ft    9.O gpm/ft

-------
CONCLUSIONS








     From the results given on the previous pages, the following



may be concluded from the pilot plant studies conducted in the



Hanover Tertiary Building.



     1.  All the filtration units tested appeared to be capable



         of producing effluent S.S. and BOD of less than 10 mg/1.








     2.  The Graver pressure filter was capable of operating at



         higher hydraulic loadings (9.0 gpm/ft2)  and S.S. loadings



         (1.9 lbs/ft2) than the other units tested.








     3.  The Neptune Microfloc unit was capable of achieving the



         best effluent quality (less than 6 mg/1 of S.S. and BOD).
                               435

-------
      EVALUATION OF 15 M.G.D. RATED CAPACITY MICROSTRAINER




            AT THE NORTH SIDE TREATMENT WORKS OF THE



         METROPOLITAN SANITARY DISTRICT OF GREATER CHICAGO






INTRODUCTION



     Following the sand filtration and microstrainer studies at



the District's Hanover Works, the staff of the MSD concluded that



the microstraining concept held promise for its North Side Treat-



ment Works.  This was based mainly upon the low land area  require-



ments of the microstrainer and the limited expansion space available



at the North Side plant-



     Although the microstrainer studied at the Hanover Works



performed adequately, it was considered to be too small for



practical consideration at the North Side Sewage Works.  The



microstrainer tested at Hanover (10'  diameter drum, 10' long) was



rated at 2.9 mgd based upon the studies conducted at Hanover.



Clearly, for a 330 mgd  (dry weather flow)  plant, such a size unit



would produce an installation with far too many individual units.



Therefore, the MSDGC decided that single units whould have a least



a 15 M.G.D. capacity for the North Side Facility.



     Because no manufacturer had produced a microstraining device



of 15 M.G.D. capacity, the MSD decided to issue a performance type



contract for only one such unit for the North Side Plant.  Commen-



surate with standard bidding procedures utilized by the District,



a contract was issued to the low bidder for such a unit and a



microstrainer constructed at the North Side Facility-




     The facility supplied to the District was a drum 40 ft. long
                                 436

-------
by 10 ft.  in diameter.  Unlike the microstrainer at Hanover, this



unit receives influent from both ends of the drum.  In addition,



the filtering fabric was not placed flat on the outer surface of



the drum,  but in a corrugated pattern.  The manufacturer stated



that this  was done to provide as much filtering area as possible



for the drum size supplied.



     The unit constructed at North Side was manufactured by the



Crane-CochraneCo. and utilized a Mark 0 stainless steel fabric



with triangular openings of 23 X 45 X 45 microns (160,000 openings



to the inch).  Again, the fabric traps the solids and rotates with



the drum to bring the fabric under wash water sprays which wash



the solids into hoppers for gravity removal to disposal.  After



the fabric is washed, it passes under ultraviolet lights to in^



hibit bacteriological growths.  With the corrugated arrangement



of the fabric on the drum, it was possible for the manufacturer



to place the fabric in removable sections.



     The drum speed and backwash pressure can be automatically



controlled by head loss through the drum.  When a set head loss is



exceeded,  the drum speed and backwash pressure are increased until



the set head loss is restored.  The unit is built for maximum head



losses of  6 inches, drum speeds of about 1 to 5 rpm and backwash



pressure of about 35 to 37 psi.



     The entire unit was housed in a heated all weather facility-



Federal funding for performance tests on the unit were obtained



and the unit began shakedown runs in November, 1971.



     The unit was tested for flow capacity, that is its ability
                                437

-------
to filter secondary effluent from the North Side Plant at flow



rates approaching 15 MGD.   Operation of the unit consisted of



achieving,  as much as practicable, a head loss of 6 inches within



the constraint of the unit's drum speed and backwash pressure.
                              438

-------
RESULTS




     In Figure 13 is presented a cuimnulative frequency of the


loadings (Ibs/ft /day) to the unit during the period of flow


capacity testing.  The unit depicts an ability to take solids


loadings as high as 1.0  Ib/ft2/day.  As noted previously for the


Hanover studies, it is believed that this expression enables


direct comparison between various types of units and sizes.


Clearly, such an expression has value since filtration devices are


designed primarily to remove S.S. and have an ability to remove


only a certain total weight per unit area given a specific head


loss and type of S.S.


     In Figure 14 is presented a cummulative frquency curve of the


flows  (24 hour) achieved by the microstrainer for the loadings


given in Figure 13.  Clearly, the microstrainer rarely achieved


the 15 MGD capacity envisioned for it and actually produced flows


averaging  (50 Percentile) 7.6 mgd.


     Plotted in this same cummulative frequency chart are the

                         2
flows expressed as gpm/ft .  It can be seen that the unit achieves

                          O
flows averaging 3.5 gpm/ft^ for the solids loading depicted in


Figure 13.


     It should be npted here that the surface area of the fabric


was taken to be total fabric area or the total area of the micro-


strainer farbir taking into account its corrugated placement on


the drum.


     In Figure 15_ is presented cummulative frequency charts of


the influent and effluent S.S. for the unit during the same flow
                               439

-------
 THE  METROPOLITAN  SANITARY  DISTRICT  OF  GREATER  CHICAGO
CUMULATIVE  FREQUENCY DISTRIBUTION  OF  INFLUENT
               SUSPENDED  SOLIDS  LOADING
             TO  NORTH SIDE  MICROSTRAINER
      100-1
    J" 60H
      40H
      20'
                           FIGURE  13
              200
4OO
600
800
1000    1200
1400    16OO
                           Suspended Solids loading, Ibs./day
             0'.1    O:2    O.3    O.4   O.S    O.6   0.7    O.8    O-9   1.O
                         Sisptided Solids Loadi&g, Ibs./ft'/day

-------
THE  METROPOLITAN  SANITARY  DISTRICT  OF  GREATER CHICAGO
 CUMULATIVE  FREQUENCY  DISTRIBUTION OF  FLOW
      THROUGH  NORTH  SIDE  MICROSTRAIfJER
     1OO-1
     80-
  .3  60-
     4O
     20
                          FIGURE  14
             1.0
2.0    3.0     4.0     5.0
       Flow gol./Bin./ft?
6.0
7.0
•.0
            2.0    4.0    6.0    8.O    10.O
                             Flow n.g.d.
                      12.0
   14.0

-------
        THE  METROPOLITAN  SANITARY  DISTRICT OF  GREATER CHICAGO
ro
             CUMULATIVE  FREQUENCY DISTRIBUTION OF
        SUSPENDED SOLIDS  IN  NORTH  SIDE MICROSTRAINER

                                 FIGURE  15
             100
             •0

                                                  INFLUENT!
                                                  EFFLUENT
                                       10    12
14    16
18
I
20
                                 Sispeided Solids mg/l

-------
capacity tests depicted in Figures 12^ and 13.   It can be  seen  that



the secondary effluent from the North Side Plant is of high quality



having an average (50 Percentile) S.S. of 11.5  mg/1 and 87 percent



of the values less than 20 mg/1.  It also can be seen that the



effluent S.S. from the unit is of high quality  having an  average



(50 Percentile) S.S. of 3.2 mg/1 with no value  exceeding  12 mg/1.



     In Figure 16 is presented a cummulative frequency distribution



of the influent and effluent BOD from the unit.  The average BOD



(50 Percentile) of the influent to the unit was 10.0 mg/1 while



85% of the values were less than 15.0 mg/1.  Effluent BOD averaged



(50 Percentile) 3.8 mg/1 while no value exceeded 13.0 mg/1.



     Backwash consumption for the unit it depicted in Figure 17.



It can be seen that the backwash is a decreasing function of flow.



This is because for the North Side unit, backwash flow remains



fairly constant over the flow rates tested.  Therefore, as flow



through the unit increases, percent backwash decreases.



     The backwash data indicates that for the average flow  (7.6 mgd)



processed by the unit during these tests, the unit required 4.6%



backwash while at maximum flow  (15 mgd) required about 3.0%.
                               443

-------
THE  METROPOLITAN  SANITARY DISTRICT OF  GREATER  CHICAGO
 CUMULATIVE  FREQUENCY  DISTRIBUTION  OF B.O.D.
CONCENTRATIONS IN  NORTH  SIDE  MICROSTRAINER

                         FIGURE  16
    100
     80
X 60
«

i_
O

O

— 40-
                                         INFLUENT

                                         EFFLUENT
             2.0
4.0    6.0     8.0

      B.O.D. mg/l
                                   10.0
12.O
14.0

-------
           THE  METROPOLITAN  SANITARY  DISTRICT  OF  GREATER  CHICAGO
           BACKWASH  DATA FOR  NORTH  SIDE  MICROSTRAINER
              20.0i
              16.0*
              12.0-
en
               8.0-
               4.0
       FIGURE  17
                                    6     8
                                     Flow ffl.g.d.
                  10
                        1.0
2.0
3.0
5.0
                                    Flow aoI./Bii./fft.a
                              i«
6.0

-------
CONCLUSIONS





     The results of the microstrainer tests at the North  Side



Plant did not prove as promising as first envisioned.  Although



effluent quality was satisfactory and well below present  Illinois



standards (Illinois standards require 30-day average BOD  values



of less than 10 mg/1 and S.S. less than 12.0 mg/1), the flow



capacity of the unit was well below that envisioned by the MSDGC.



     The North Side unit has proven itself capable of taking flows



on the average (50 Percentile) of about 7.6 mgd with corresponding



solids loadings averaging (50 Percentile)  about 0.5 Ibs/ft^/day.



Effluent quality for the Mark O stainless steel fabric appears to



be capable of meeting present Illinois S.S. and BOD standards.



Backwash valume for the unit operating at an average flow capacity



was about 4.6%.
                               446

-------
   SUMMARY  COMPARISON OF TEST RESULTS OF FILTRATION DEVICES



                             TESTED







     In  Table £ is contained a summary of the operating and per-



formance parameters for the filtration devices discussed in this



paper.   The  following may be concluded from a comparison of these



summarized results.





     1.   The North Side Microstrainer although capable of achieving



         the maximum flow capacity of the Hanover Microstrainer



         on  a short-term basis, could not consistently achieve



         the maximum flow for the Hanover unit.  This could in-



         dicate that microstrainer flow capacity is severly de-r



         pendent on the type of effluent solids.





     2.   It  appears that the microstraining devices cannot achieve



         the S.S. removal performance of sand filters.





     3.   It  appears that batch type filters are capable of loadings



         over 1.2 Ibs/ft2/filter run.
                                447

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              METROPOLITAN  SANITARY  DISTRICT  OF  GREATER   CHICAGO
                                            TABLE
             COMPARISON  OF  OPERATING  AND   PERFORMANCE
                   PARAMETERS  OF  THE  FILTRATION  DEVICES
                                   TESTED   BY  THE  MSD
               PARAMETER
                                                HARDINGE DELAVAL MICKOFLOC GRAVER
                     HANOVER PARK   NORTH SIDE     SAND    SAND     SAND    SAND
                     MICROSTRAINER MICROSTRAINER   FILTER    FILTER     FILTER    FILTER
00
FLOW RATE (GPM/SQ FT)
     Maximum
     Range Tested
LOADING
     Maximum
BACKWASH (%)
     At Max. Flow
     Range
EFFLUENT BOD (MG/L)
     At Max. Flow
     Range
EFFLUENT S.S. (MG/L)
     At Max. Flow
     Range
6.6
0-6.6

0.88 **
0-0.88 **

4.0
0-3.0

4.0-
1-5

5.0  *
1-10
6.3
0-6.3

1.0**
0-1.0

2.9
0-16
                                               0-11
                                               0-12
6.0
0-6.0    0-5.0    0-4.0    0-9.0

0.65 **
0-0.65** 0-L24**  0-1.53    0-1.9*
                                                          0.65
                                                          0-0.65   0-3.7     0-2.5    0-1.14
2.3'
1-4

5.0 *
1-9
                                                          5-9
                                                          5-7
                            4.0-6.0   3.5-8.0
                            4.0
                          5.9
                 • For Influent BOD of 18 mg/l and Maximum Loading
                 A For Influont S.S. Equal* 18 mg/l and Maximum Loading
                                                         * Ibs/sq ft/filtor Run

                                                        ** Ibs/sq ft/day

-------
                             .METRO  CHICAGO

                        STUDIES ON  NITRIFICATION
                 -BART T. LYNAM, GENERAL SUPERINTENDENT
        THE METROPOLITAN SANITARY  DISTRICT OF GREATER CHICAGO
                          CHICAGO,  ILLINOIS
                             PRESENTED AT

     THIRD U.S./JAPAN CONFERENCE ON SEWAGE  TREATMENT TECHNOLOGY
                             TOKYO, JAPAN

                             FEBRUARY 1974
CO-AUTHORS:  DAVID  R.  ZENZ,  COORDINATOR OF RESEARCH
             CECIL  LUE-HING, DIRECTOR, RESEARCH AND DEVELOPMENT
             GEORGE R.  RICHARDSON, HEAD, WASTEWATER RESEARCH  DIVISION
             BOOKER T.  WASHINGTON, SANITARY CHEMIST I
             THE METROPOLITAN SANITARY DISTRICT OF GREATER  CHICAGO
                               CHICAGO, ILLINOIS
                                  449

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                       TABLE  OF CONTENTS


List of Tables

List of Figures                                                452

I.    INTRODUCTION                                             453

-II.   TWO STAGE NITRIFICATION  AT HAZELCREST,  ILLINOIS         457

      A.  Introduction                                        457

      B.  Results                                              457

          1.  Phase  I  -  Initial Testing Period
              April  20 - July  30,  1969                         458

          2.  Phase  II - December  15  -  March  24,  1970         464

      C.  Conclusion                                          469

III.  CALUMET NITRIFICATION  PILOT  PLANT                       47Q

      A.  Introduction                                        470

      B.  Results                                              472

      C.  Conclusions                                          435

IV.   NITRIFICATION  AT LEMONT,  ILLINOIS -  EXTENDED AERATION   487

V.    SUMMARY                                                  494

VI.   NITRIFICATION  OF A HIGH  AMMONIA CONTENT SLUDGE
      SUPERNATANT BY BIOLOGICAL PROCESSES                      495

VII.  REFERENCES                                               503
                             450

-------
                      LIST OF TABLES
Table 1.  Calumet Raw Sewage Characteristics Monthly
          Averages During Pilot Study

Table 2.  Return Sludge Trace Metal Analyses - Averages

Table 3.  Lemont - WRP November 1972

Table 4.  Metals in Return Sludge of Lemont - WRP

Table 5.  Chemical Characteristics of Sludge Lagoon
          Supernatant from Fulton County
471

483

491

492


497
                               451

-------
                          LIST OF FIGURES
Figure 1.

Figure 2.


Figure 3.

Figure 4.

Figure 5.


Figure 6.


Figure 7.

Figure 8.

Figure 9.

Figure 10.


Figure 11.


Figure 12.


Figure 13.

Figure 14.

Figure 15.

Figure 16.

Figure 17.
District Map

Time Series Plot of Raw NH3~N Effluent
N02-N03 and

Time Series Plot Second Stage BOD Loading

Time Series Plot Second Stage MLTSS

Time Series Plot Second Stage Ammonia
Loading

Time Series Plot Second Stage Effluent
NH3 and NO.-NO,
          ft   »J

Time Series Plot Second Stage BOD Loading

Time Series Plot Raw Sewage Temperature °F

Time Series Plot Second Stage MLTSS

Schematic of Second Stage Biological
Nitrification System

Pilot Plant Influent and Effluent NH3~N
Concentration

Frequency Distribution of Effluent TSS from
the Calumet Nitrification Pilot Plant

Weekly Variations in Aluminum Concentration

Weekly Variations in Chromium Concentration

Schematic of Lemont Water Reclaimation Plant

Performance of The Slurry System

Performance of the Rotating Disc System
454


459

460

461


463


465

466

467

468


473


475


478

481

482

488

499

500
                               452

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INTRODUCTION




     The Metropolitan Sanitary District of Greater Chicago  (MSDGC)


collects  and treats more than one billion 250 million gallons


of domestic and industrial waste each day.  It has a capacity


of 1,600,000,000 gallons a day and its growth and ungrading


continues in order to keep pace with the needs and demands of


the communities which it serves and to produce higher quality


effluents in order to upgrade all water resources in the State


of Illinois.


     The District maintains a waterway system which consists


of 85 miles of navigable waters including canals, channels and


rivers  (Figure ,1) .  In addition, hundreds of miles of secondary


tributaries and storm sewers also drain into the main waterway


system.  Because the District' s three maj.or sewage treatment


plants and four small treatment plants discharge effluent to


the drainage basin, more stringent criteria are being placed


on the quality of effluent discharged.  These criteria cover


a wide spectra such as carbonaceous oxygen demand, toxic


substances, nutrients and oils and greases.  The MSDGC has


directed considerable efforts toward the removal of nitrogen


and phosphorus nutrients in order to develop effective and


economical procedures.


     It is now realized that besides it's role as an indicator

                                                   (1 2}
of pollution, ammonia itself is a serious pollutant. '


Ammonia nitrogen in waste treatment effluents has been held


undesirable due to the following reasons:
                              453

-------
                                    DISTRICT MAP


                                      FIGURE 1
          THEjMETROPOLITAN SANITARY! DISTRICT OF\3REATER CHICAGO
                                                                      LAKE
                                                                       MICHIGAN
                                                                       CHICAGO RIVER
SRUNDY CO !
£ a.     D TREATMENT PLANTS
•d 3
                 STATIONS
               lNTERCEPTING  SEWERS
                                                       WEJST-SOUTHWEST

                                              w  [	-	-i
                                         454

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     1.   It reacts with chlorine during the disinfection



         process and produces chloramines which are less



         effective as disinfectants than free chlorine and



         may subsequently cause an increase in the chlorine



         demand.








     2.   This constituent exerts a toxic effect on aquatic



         life at high concentrations.  This has been demon-



         strated by investigators to be particularly toxic



         on fish life.








     3.   It exerts an oxygen demand on the receiving waterways



         and will subsequently, when oxidized to other nitrogenous



         forms act as a nutrient for undesirable algae forms.








     The Illinois Pollution Control Board  (IPCB) Rules and



Regulations, Chapter 3, Water Pollutions require in Rule 406 ^ '



that "No effluent from any source which discharges to the



Illinois River, the Chicago River System, or Calumet River



System,  and whose untreated waste load is 50,000 or more popu-



lation equivalents shall contain more than 2.5 mg/1 of ammonia



nitrogen as N during the months of April through October, or



4 mg/1 at other times, after December 31, 1977."  This rule



will require that the three major treatment plants of the



Metropolitan Sanitary District of Greater Chicago, namely the
                               455

-------
North Side Sewage Treatment Works, the West-Southwest Sewage

Treatment Works, and the Calumet Sewage Treatment Works remove

ammonia nitrogen from their effluents after December 31, 1977.

     To this end the MSDGC has undertaken pilot process studies

to evaluate alternate procedures for removing ammonia nitrogen

from its secondary treatment effluents.

     After serious consideration of the physical-chemical and

biological processes available for ammonia removal, it was

decided that secondary or unresolved problems made the physical-

                                            (4 5)
chemical processes unfeasible at this time.    '

Therefore, the MSDGC concentrated its efforts on the biological

processes for ammonia removal.

     This paper will present some of the data collected on several

of the biological treatment projects conducted from 1969 through

1973.  These data will be discussed in the following order:

    1.  Two-Stage Nitrification at. Hazelcrest, Illinois

   11.  Calumet Nitrification Pilot Plant

  111.  Nitrification at Lemont, Illinois -  Single Stage
        Extended Aeration

   IV.  Nitrification of a High Ammonia Content Sludge Super-
        natant by Biological Processes
                              456

-------
    Two-Stage Nitrification at Hazelcrest, Illinois
     The 1.2 mgd design capacity treatment facilities at
Hazelcrest, Illinois, were converted from two parallel activated
sludge systems to a two-stage biological nitrification process.
The total capacity of the nitrification plant was approximately
0.6 mgd.
     In April of 1969, the Hazelcrest facility began operating
as a two-stage nitrification process.  However, it was not until
June of the same year that the system attained a satisfactory
level of nitrification.  This level of nitrification continued
through the month of December 1969.  During this period of
operation, the detention time ranged from 4.5 to 3.6 hours for
the first and second stage reactors.  The first and second stage
clarifier  detention times ranged from 1.95 to 1.56 hours and
3.22 to 4.03 hours respectively.  These detention times were
calculated on an average flow of 0.8 and 1.0 mgd which were the
range of flows generally experienced by the plant.

Results

     The summary data of the Hazelcrest project will be presented
in two phases.   Phase I will show data for the initial start-up
and a period of successful operation.  Phase II will show data
after the nitrification process was interrupted and steps were
taken to re-establish it.
                               457

-------
     Phase I - Initial Testing Period  (April 20 - July  30,
1969
     As in any start-up period, there were fluctuations in




plant operation.  Once the plant reached a point of steady state




operation, mixed liquor suspended solids in the first stage



reactor had to be maintained between 1HOO and 2000 mg/1.  If




the mixed liquor solids were allowed to exceed 2000 mg/1, excess



solids were carried over into the second stage.



     On May 1, solids wasting from the second stage was




discontinued to build up the mixed liquor solids.  By following



this procedure mixed liquor solids concentrations were main-



tained between 2800 and 3000 mg/1.  It was only necessary to




waste occasionally to prevent second stage effluent deterioration,



     The data obtained during this period of study will be



presented in the next four figures.  It can be seen from the



nitrate - nitrite and ammonia curves (Figure 2) that the plant



approached a satisfactory point of nitrification around June 23



and continued to nitrify at this level through July 30.  The



average raw NH3~N concentration of 12 mg/1 was reduced to an



average concentration of 1.5 mg/1 in the second stage effluent.



The nitrate-nitrite concentration ranged from 10.0 to 17.0 mg/1.



The temperature ranged from 50°F to 64°F during this phase of



study.




     As can be seen from Figures 3_ and _4, the second stage



reactor operated with an average loading of 0.10 Ib BOD/lb
                               458

-------
    METROPOLITAN  SANITARY  DISTRICT  OF  GREATER  CHICAGO
                              FIGURE  2
E
    15-


    10-
    0-
   20


   15;


   10


    5


    0
   70-


   60


   50
I—  40
-SECOND STAGE NH3 AS N

                               \   i\
                               \J\rJ
              -TEMPERATURE

SECOND STAGE NO2+NO3AS N
        5  10  15  20  25  30
                  10  15  20  25  30
                     Jane
10  15  20  25
    Jily
30
        TIME  SERIES PLOT OF RAW  SEWAGE AMMONIA, EFFLUENT  (NO 2 & N03)
      AND  EFFLUENT AMMONIA  AND RAW  SEWAGE TEMPERATURE AT  HAZELCREST

-------
           THE  METROPOLITAN  SANITARY  DISTRICT  OF  GREATER  CHICAGO
                                          FIGURE  3
          a «/>
                0.3
                0.4
                0.3
cr\
o
          S
                0.2-
                0.1
                   20  25  30   5  10  15   20  25   30   5  10  15   20  25  30  5  10  15
                    April
May
June
Jily
                  TIME SERIES PLOT SECOND  STAGE  B.O.D.  LOADING  AT HAZELCREST

-------
               KtETROPOUTAN  SAUiTARY   DISTRICT  OF   GREATER  CHICAGO
-p.
cr>
£
 ^
V)



&E
30OO-
         ? 2000-
           1OOO-
                                                                           •    i   i
               20  25  30  5   10  15   20  25  30   5  10  15  20  25  30  5  10   15  20  25
                                                     Joce
                                                                 h\1
                     TIKE SERIES  PLOT  OF SECOND  STAGE  fcUTSS  AT  HAZELCREST

-------
MLTSS/day and a mixed liquor suspended solids range of  2500




to 3500 mg/1 from April 20 to July 30, 1969.



     Figure 5 presents data on the NHj-N loading to the second



stage.  The loading was generally less than 0.04 Ibs NHj/lb




MLTSS/day-  The plant continued to nitrify at about 90% effi-




ciency with NH3-N less than 1.5 mg/1 through the month of




October.



     To select or choose factors responsible for achieving



the degree of nitrification observed is difficult but one may



consider several factors.  A comparison of the data presented



in the graphs for the period of satisfactory and unsatisfactory



nitrification is of interest.  The organic loading to the second



stage was somewhat lower during satisfactory nitrification.




Also, sewage temperature appears to exert a significant effect



on nitrification.  From April 20 through May 21, the temperature



was 50°F at which time there was no nitrification.  There was



some nitrification when the temperature increased to 59and 60°F.



The temperature remained at this level for 30 days and the plant




was nitrifying at 50% efficiency.  When the temperature increased



to 63 and 64°F the plant began to produce complete nitrification.
                              462

-------
CO
              METROPOLITAN  SANITARY  DISTRICT  OF  GREATER  CHICAGO
                                         FIGURE  5
           0.05-
         M 0.04-
           0.03-
           O.O2*
           0.01
               0  25  30  5  10  15  20  25  30   5  10   15  20  25  30  5   10  15  20
April
                               May
Jine
J.ly
                      TIME  SERIES  PLOT  OF SECOND STAGE  AMMONIA LOADING
                                       AT HAZELCREST

-------
     Phase II - December 15, - March  24,  1970








     As previously noted, the Hazelcrest  Plant produced a  well




nitrified effluent during the months  of November  and  December.




However, about January 1, 1970 a decrease in second-stage




nitrate levels and a corresponding increase in the NH3-N level



occurred.  This decrease in plant efficiency is depicted in




Figure 6^  A clear indication of the  exact cause  of the  cessa-



tion of nitrification is not evident  but  certainly several



factors must be considered to have significantly  contributed to




the effect.



     The organic loading to the second stages (Figure _7) was



high, averaging about 0.3 Ib BOD/lb MLTSS/day.  As indicated



in Phase I, a more reasonable figure  for  the second stage loading



would be 0.1 Ib BOD/lb MLTSS/day.



     Another factor contributing to the lack of nitrification



was the relatively low raw sewage temperatures that occurred



January 1, 1970, and thereafter  (Figure  8).  This average




temperature of 47°F was much lower than the temperature  experi-



enced in the spring of 1969, at which time partial nitrification



was obtained.




     It was also possible (Figure 9_)   that the relatively large



fluctuations in MLTSS did not contribute  favorably to the nitri-



fication process.   The inability to maintain a steady-state




operation with respect to the above parameters was certainly a
                               464

-------
THE  METROPOLITAN  SANITARY  DISTRICT  OF  GREATER  CHICAGO
                            FIGURE  6
                                          NH,
  15  20   25  30    5   10  15  20  25  30   5   10  15   20  25  1  5  10  15  20
     December
Janiory
February
ltd arch
           TIME  SERIES  PLOT  SECOND  STAGE EFFLUENT AMMONIA
                  AND  (N02 + N03) AT  HAZELCREST

-------
            THE  METROPOLITAN  SANITARY  DISTRICT  OF  GREATER  CHICAGO
                                         FIGURE  7
cr>
             15  20  25  30  2  5   10  15  20  25  30   5  10 15  20 25   5  10  15  20
               December             January               February          March
                  TIME SERIES PLOT SECOND STAGE  B.O.D. LOADING  AT HAZELCREST

-------
          THE  METROPOLITAN  SANITARY   DISTRICT  OF  GREATER  CHICAGO


                                               8
       n.
01

—I
         .,
         45
         40
           15  20  25  30   5  10  15  20  25  30   5  10  15  20  25  1   5   10   15  20
              December
February
Harch
                     TIME  SERIES  PLOT  RAW SEWAGE TEftP.  AT  HAZELCREST  ILL.

-------
            THE  METROPOLITAN   SANITARY  DISTRICT   OF  GREATER  CHICAGO

                                          FIGURE  9
CTi
00
                  3500<
«/*
«£    3000
                  25OO
                  2000
                     15   10  25  30    5   10  15  20  25  1   5   10   15  20   25
                        January
                            Febnary
March
                       TIME  SERIES  PLOT  SECOND  STAGE MLTSS AT  HAZELCREST

-------
detriment to the system.



     Due to the absence of flexibility in the operation of the



plant, it was difficult to determine precisely the total or



direct effect of the various parameters believed to exert adverse



changes on the nitrification process.  However, the following



conclusions were drawn from the MSDGC experiences with this



study.



     1.  A two-stage activated sludge process can produce an



         effluent high in nitrate - nitrite and low in ammonia



         concentrations at a detention time of 3.0 to 5.0 hours



         in the second stage.








     2.  It is necessary for the first-stage system to perform



         efficiently in organic and suspended solids removal to



         prevent detrimental carry-over of these materials into



         the second stage.








     3.  Temperature effects appear to be a major factor in



         initiating and maintaining nitrification.








     4.  A highly nitrified effluent can be produced when the



         NH3 loading is less than 0.04 ibs/MLVSS/day to the




         second stage.
                               469

-------
     Calumet Nitrification Pilot Plant








     Introduction








     The Calumet Sewage Treatment Plant, located in the south-




eastern section of the City of Chicago and serving this general



portion of the city and Cook County, was placed into operation




in 1935.  The present plant receives combined domestic and



industrial sewage from an area of approximately 270 square



miles.  The plant's sewage processing facilities include preli-




minary and secondary treatment, anaerobic sludge digestion, and



contact chlorination.



     There is a wide range of industries operating within the



Calumet Treatment Plant service area, such as steel mills,



coking plants, paint and chemical manufacturers, and grain  and



transport companies.  These and other regional industries contri-




buted an estimated 60 - 70 mgd of the average 199 mgd of sewage



volume which the Calumet Plant processed in 1972.  Table 1^



lists some of the pertinent characteristics of the Calumet raw



sewage obtained during the six months in which the Calumet



Nitrification Pilot Plant was operated.
                              470

-------
     THE  METROPOLITAN  SANITARY DISTRICT
             OF  GREATER  CHICAGO
                  TABLE 1
   CALUMET NITRIFICATION  PILOT PLANT
 CALUMET RAW SEWAGE CHARACTERISTICS
MONTHLY AVERAGES  DURING  PILOT  STUDY
TKN
NOV. 1972
DEC.
JAN. 1973
FEB.
MAR.
APR.
AVERAGES
24
29
28
.1
.9
.3
32.4
24
.4
22.8
27.0
NH^N
15.
6
17.8
18.0
23.7
17.
15.
6
7
pH
7.5
7.
5
7.4
7.
7.
7.
4
5
6
18.1
TSS
194
265
178
174
192
231
206
YSS
121
157
113
107
108
116
120
BOD
106
149
136
148
130
113
130
COD
245
330
287
312
262
234
278
    Results expressed In mg/l, except for pH.
                     471

-------
     Results








     From November 1, 1972, through April 24, 1973, a two-stage



bench-scale nitrification feasibility study was conducted at



Battery C of the Calumet Sewage Treatment Plant.  The final



effluent from Battery C was utilized as the influent feed to a



20.6 gallon, compartmentalized pilot reactor which constituted



the second stage of a two-stage biological treatment process.



A schematic of the pilot plant is shown in Figure 10.   Within



three days of start-up of the pilot plant, significant nitrifi-



cation was observed and was maintained at approximately 90 per



cent ammonia nitrogen removal until the completion of the project,



     The data collected for the nearly six months of operations



has been summarized as follows:



     1.  Substrate Loading and Substrate Removal



              The influent feed ammonia nitrogen averaged 17.5



         mg/1, with the weekly averages ranging from 10.1 to



         24.9 mg/1; this included a supplemental 10 mg/1 NI^Cl



         dosing to the reactor which was initiated during the



         latter phase of the study.  The average ammonia nitrogen



         reactor loading rate was 0.126 Ibs NHs-N/lb MLVSS/day;



         weekly averages ranged from 0.041 to 0.273 Ibs NH3~N/lb



         MLVSS/day.  Effluent ammonia nitrogen concentrations



         averaged 2.1 mg/1, an average of 88 per cent removal.



         The average ammonia nitrogen removal rate was 0.109



         Ibs NH3-N/lb MLVSS/day.
                               472

-------
                            THE METROPOLITAN SANITARY DISTRICT OF GREATER CHICAGO
                                    CALUMET NITRIFICATION PILOT PLANT
                 INFLUENT FEED
CO
                          REACTOR (20.6 GALLON CAPACITY)
                                  RECYCLE TO REACTOR
                                                                                    EFFLUENT
                                                                            (ASSUME NO WASTE)
                                                FIGURE 10
                          SCHEMATIC OF 2ND- STAGE BIOLOGICAL NITRIFICATION SYSTEM

-------
         Figure JL1  details the variability in ammonia




    nitrogen for influent and effluent streams and the



    resultant % removal for the initial five days of




    start-up, and the subsequent 25 weekly averages.  The



    effluent ammonia nitrogen observed for weeks 15, 16,




    and 17 were high, averaging 4.6 mg/1, due to insuffi-




    cient mixing in the aeration tank which resulted in



    inadequate oxygen transfer.  However, as indicated, the




    effluent quality was greatly improved by the 18th week,



    following correction of the mixing problem.   Again,



    during the period between the 21st week and the 23rd



    week of operations, operational difficulties (which in




    this case was the loss of the nitrifying population as



    a consequence of the reactor overflowing)  resulted in



    high ammonia nitrogen bleed-throughs to the effluent.



    The residual effluent ammonia nitrogen obtained for



    this period averaged 3.4 mg/1.   As was previously stated,



    effluent NH3-N averaged only 2.1 mg/1 over the full 25



    weeks of the study.








2.   Effect of Change in Detention Time




         The nitrification reactor was successfully operated



    at detention times of 4.0,  3.0 and 2.0 hours, based on



    influent flow rate only, for periods of 82,  42 and 51



    days, respectively.  Throughout the study recycle sludge
                            474

-------
METROPOLITAN  SANITARY  DISTRICT  OF  GREATER CHICAGO
                             FIGURE  11
                CALUMET  NITRIFICATION  PILOT  PLANT
           Pilot Plait  liflieit  »d Efflteot NH3-H Coiceitutlois
                           7» Removal of Ammonia
     	\ \
     n  i  i  i v \ i
013345
Start-up, Days
                            •   10   12  14   16
                               Weekly Averages
                                               30   23
                                                       24

-------
    was pumped to the head of the reactor at rates of



    either 50% or 75% of the influent flow.  Excluding



    the initial start-up week, the average effluent ammonia



    nitrogen was 0.9, 2.8 and 2.0 mg/1, respectively, for



    the detention times investigated.








3.  Solids Retention Time, SRT



         For the first 11 to 12 weeks of this study,  efforts



    were not directed towards maintaining a sludge age of



    any particular number of days.  However,  for the  remaining



    weeks of the study, attempts were made to control the



    sludge age at an average of at least ten  days. This



    was done by periodically adding settled return sludge



    from Battery C to the nitrification reactor whenever



    effluent suspended solids losses and/or accidental



    sludge wasting resulted in MLVSS levels  of approximately



    1000 mg/1 or less.  The average SRT obtained during



    this latter phase of operations was nine  days at  an



    average reactor temperature of 15°C.








4.  BOD and Suspended Solids Considerations








         Influent BOD and TSS to the second-stage reactor



    averaged 18 mg/1 and 13 mg/1,  respectively, whereas



    effluent BOD and TSS averaged, respectively, 29 mg/1
                            476

-------
    and 26 mg/1.  Typically, BOD and suspended solids



    removal through the nitrification unit was not observed



    once nitrification commenced.  Figure 12_  indicates



    the frequency distribution of effluent TSS which was



    obtained for each of the two major clarifier overflow



    rates at which the clarifier was operated/ namely 287



    gal/sf/day and'382 gal/sf/day.  As shown, the higher



    effluent TSS were more often observed at the higher



    clarifier overflow rate.








5.  Maintenance of Mixed Liquor Volatile Suspended Solids



         Weekly averages of mixed liquor suspended solids



    ranged from 1151 rag/1 to 3642 mg/1, averaging 2115 mg/1



    of which an average 1359 mg/1 (64.2%) was MLVSS.  It



    was necessary to periodically add settled return sludge



    from Battery C to the nitrification unit in order to



    maintain a level of 1000 - 1500 mg/1 MLVSS.  The addition



    of return sludge to the reactor occasionally resulted



    in a transient  upset in nitrification efficiency.  This



    was adjudged to be due to dilution of the nitrifying



    population and was considerably lessened by a slow



    addition of the solids to the reactor.








6.  Temperature Observations



         Since there were no provisions for controlling the
                             477

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oo
                METROPOLITAN   SANITARY  DISTRICT  OF  GREATER  CHICAGO


                                   CALUMET  NITRIFICATION  PILOT PLANT


                                              FIGURE   12
                  60-
              9

              V
             u

             L.
                  40-
                  30-
                                            Clorifier Overflew Rate = 287 gal/»f/day
                                                     Clarifier Overflow Rate = 382 gal/sf/day
                             i
                             o
                                     o
                                     n

                                     I
o
n
o

T
                                                                      o
                                               Effluent TSS , mg/l
                     Frequency Distribution of Effluent TSS from the Calumet Nitrification Pilot Plant

-------
    temperature of the nitrification unit, aeration



    temperatures varied with changes in feed and ambient



    temperatures.   Average weekly reactor temperatures



    ranged from 22°C to 13°C over the six months involved



    in the study.








7.   pH and Alkalinity Observations



         pH control did not present any operating problems



    with the Calumet Nitrification Pilot Plant.  The influent



    pH ranged from 7.4 to 7.7, and effluent pH ranged from



    7.3 to 7.8 over the 25 weeks of the study.  Sawyer,



    (Ref. 6) from his studies at Marlborough, Mass.,



    recommended a mixed liquor pH range  of 7.6 to 7.8 in



    order to allow carbon dioxide to escape to the atmosphere.



    This pH range would still be sufficiently close to the



    theoretical maximum pH of 8.4 to insure a high nitri-



    fication rate.  The pilot plant mixed liquor pH's ranged



    from 6.9 to 7.7, and nitrification was apparently not



    attentuated at these pH levels.



         Effluent alkalinity concentrations ranged from 60



    to 650 mg/1, averaging 174 mg/1.  The average alkalinity



    consumption was 5.2 Ibs alkalinity (as CaCO3)/lb NH3-N



    oxidized and ranged from 1.2 to 7.8 ibs alk/lb NH3-N



    oxidized.
                              479

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Trace Metal Effects



     Two aspects of high trace metal concentrations



were considered in this study:   (a) the effects of



influent concentrations of trace metals on the nitri-



fication process, and  (b)  the extent and effect of



trace metal accumulation in the return sludge.  Of the



14 metals monitored/ none were found to be significantly



high in either the influent or effluent streams.  Typically,



influent and effluent concentrations of metals were



about the same; this is reflected in Figures 13 and ^4



for two of the metals, Al and Cr.  There were no occasions



when upsets in nitrification efficiency were attributable



to the concentrations of trace metals observed in the



influent stream*



     Table !2  lists the average return sludge trace



metal concentrations for Calumet Battery C and also for



the nitrification pilot plant.  As shown, some of the



pilot plant trace metal values exceeded those of Battery



C, whereas others were less.   This merely reflected the



variability in trace metal concentrations that was



observed for the pilot plant return sludge.  This



variability was due to periodic sludge losses through



accidental sludge wastage and high effluent suspended



solids, and sludge additions which were required to



replenish those losses.  Thus, as assessment of trace
                         480

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                 METROPOLITAN   SANITARY  DISTRICT   OF  GREATER  CHICAGO

                                  CALUMET NITKIfKATION  PILOT  PLANT


                                             FIGURE  13
                 7.0-
00
                 3.0-
             E
             9
             c
                 0.4-
^••i Influent, Average = 0.7 mg/l


'**** Effluent, Average = 0.9 mg/l
                                                 13

                                               Weeks
                                                           16
            JO
                                Wtekly Variations in Alinitum Coicentration
                                                                                    X

-------
00
            METROPOLITAN  SANITARY  DISTRICT  OF  GREATER  CHICAGO
                              CALUMET NITRIFICATION  PILOT  PLANT

                                     FIGURE  14
            o.o«
                    Influent, Average = 0.02 mg/l

                    Effluent, Average = 0.03 mg/l
           0.06'
           0.04
         o
         J:
         u
           0.02
                                                    v\/\
                                                                    24
                         Weekly Variations in Chromium Concentration

-------
              OF  GREATER   CHICAGO
CALUMET
                   T3ACE  ;V£7:U ANALYSES  & ATOAG2S
        (Results Expressed in rag/1 except Hg. Hg ta ug/g)

Zn
Cd
Cu
Cr
Fa
HI
Pb
K
Na
CQ
Mg
Mn
Al
Hg
CALU^iT SATTESY 'C'
2.23
0.070
0.148
0.493
13.8
0.062
0.504
3.95
11.0
43.2
13.4
0.256
4.23
1.34
CAlU$n PILOT PLANT
1.86
0.053
0.135
0.531
14.7
0.037
0.431
3.41
19.4
37.9
13.5
1.121
4.37
2.22
  HOTS: A91 Vohas Calculated on G dry weigh? basis.
                         483

-------
    metal accumulation in the return sludge could not be



    properly evaluated.








9.   Dissolved Oxygen Considerations



         The amount of air supplied to the reactor was



    determined in great measure by the need to keep the



    MLSS in suspension via the bubbling actions of the



    compressed air.  Thus, although the air input was



    measured,  as was also the reactor dissolved oxygen,



    the values obtained were  not reflective of what would



    be expected in a full-scale plant.
                            484

-------
     Conclusions








     The following conclusions were derived from the results



obtained by operating the Calumet Nitrification Pilot Plant:



     1.   The Calumet Treatment Plant, with a second-stage



         nitrification system, could reasonably be expected



         to produce a nitrified effluent with an ammonia



         nitrogen residual of less than 2.5 mg/1 under the



         following conditions:



              influent NH3-N, 10 - 25 mg/1



              SRT, at least 10 days



              minimum operating temperature, 12 - 15°C



         It must be emphasized that the lowest average temperature



         of 12QC recorded in the pilot plant aeration tank was



         approximately 2 - 3°C higher than that observed in the



         full-scale aeration tanks.  Therefore, since a lower



         second-stage aeration temperature would be expected in



         an on-line plant, cold temperature nitrification studies



         on the Calumet sewage will be undertaken.








     2.   The average alkalinity consumption of 5.2 Ibs alkalinity/



         Ib NH3-N oxidized that was required in the nitrification



         of Calumet Battery C effluent correlates reasonably



         well with the theoretical demand of 7.2 Ibs/lb NH3-N



         oxidized.  Since Battery C effluent supplied this demand
                                485

-------
    without   resulting pH depressions through the nitri-



    fication unit, it would be expected that future nitri-



    fication of Calumet sewage would not entail supple-



    mentation of the treatment stream alkalinity.  However,



    in alkalinity deficient or high ammonia content waste-



    waters which are undergoing biological nitrification,



    it is expected that alkalinity additions will be required,








3.   The preceeding first-stage sludge of the carbonaceous



    system apparently reduced influent concentrations of



    trace metals to non-inhibitory levels.   However,  the



    effects of trace metals upon nitrification in a single-



    stage system,  under the conditions listed,  are not known.
                            486

-------
      Nitrification at Lemont, Illinois - Extended Aeration



     The Lemont Water Reclamation Plant (WRP) treats sewage

primarily from the Village of Lemont, a town of about 5000

located in southwestern Cook County.  The plant was designed in

1969 and completed in mid 1972.  The schematic (Figure 15) shows

the treatment processes employed at the plant.  A brief descrip-

tion of plant facilities is as follows:



Design capacity                                    1.2 mgd

Maximum flow receiving complete treatment          3.0 mgd



A.  Grit and screening

B.  Primary settling
    Two 45 ft. diameter tanks
    Detention time at 1.2 mgd - 4.5 hr.
    Surface settling rate - 380
C.  Aeration tanks
    Two single pass tanks 120 ft by 25 ft, 13.5
    depth
    Detention time at 1.2 mgd - 12 hr
    Diffused aeration with 6000 cfm blower capacity
    100% sludge return capacility

D.  Final settling tanks
    Two 36 ft. diameter center feed tanks
    Detention time at 2.4 mgd mixed liquor flow - 3.7 hours
    Surface settling rate at 2.4 mgd mixed liquor flow -
    600 gal/ft/day

E.  Micros trainers
    Two 10 ft by 10 ft Zurn microstrainers
    Design flow (each)  - 1.2 mgd
    Maximum flow (each) - 1.7 mgd
    Screen size - 23 microns
                              487

-------
  THE METROPOLITAN SANITARY DISTRICT OF GREATER CHICAGO

                      FIGURE J5

LEMONT WATER RECLAMATION PLANT SCHEMATIC DIAGRAM

                         RAW
                       SEWAGE
                     GRIT REMOVAL
                    AND SCREENING
                       PRIMARY
                    SEDIMENTATION
                      EXTENDED
                      AERATION
                        FINAL
                    SEDIMENTATION
                   MICROSCREENING
                    CHLORINATION
                      EFFLUENT
                         488

-------
F.  Chlorination
    Sodium hypochlorite with chlorine contact chamber.

G.  Sludge treatment
    Gravity sludge thickening tank
    Two complete mix digesters with external heat exchangers,
    3200 ft3 capacity
                            489

-------
    The aeration facility was designed to utilize the extended



aeration process in order to provide nitrification as well as




BOD and suspended solids removal.  The extended aeration process




has worked out rather well at this plant.  The final clarifier



effluent ordinarily averages about 5 mg/1 BOD and 10 mg/1



suspended solids.  Effluent ammonia generally is less than 0.5




rag/1.



    Table 3_  summarizes the operating results for November 1972,




a fairly typical month.  Influent ammonia nitrogen averaged



11.1 mg/1 and effluent ammonia nitrogen averaged only 0.2 mg/1,



a reduction of 98 per cent.  Effluent nitrate nitrogen increased ac-



cordingly by an average of 12 mg/1.  Plant flow averaged 1.26




mgd, resulting in an average aeration tank detention time of



11 hours.  The MLSS averaged J460 mg/1 and it's interesting that



the  plant has never encountered any serious settling problems.



The BOD loading and F/M ratio were as would be anticipated from



the extended aeration process very low.



    The extended aeration process typically has long aeration



times and low sludge wastage rates.  Average  monthly aeration



tines have varied from 10 hours to 26 hours.  Because of low



sludge production,  weekly grab samples of the return sludge were



analyzed for metal  content to ascertain if any concentration was



occurring.  Table 4^  shows the average monthly results from



December 1972 through June 1973.  There is to date no evidence



of metal concentration in the sludge.
                                490

-------
   THE  METROPOLITAN  SANITARY  DISTRICT
            OF  GREATER  CHICAGO
                  TABLE  3
OPERATING  RESULTS  OF  LEMONT - WRP
             NOVEMBER 1972
NH3-N Primary
NH3-H Final
Percent Reduction
N03-N and N02-N Primary
N03-N and N02-N Final
N03-N and N02-N Increase
Flow to Aeration Tanks
Detention Time
BOD Loading
MLSS
F/H
D.O. Final
Temperature Final
S.S. Raw
S.S. Primary
S.S. Secondary
BOD Raw
BOD Primary
BOD Secondary
11.1 mg/1
0.2 mg/1
98%
1.47 mg/1
13.60 mg/1
12.13 mg/1
1.26 mg/1
11 hours
13 Ibs/IOOOft3
3460 mg/1
One Ibs POP
" It MJ iff
8.2 mg/1
54°F
101 mg/1
85 mg/1
10 mg/1
128 mg/1
96 mg/1
5 mg/1
     Range of Detention times for November 1972 were 5^ to 24 hours.
                      491

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    THE  METROPOLITAN  SANITARY   DISTRICT
               OF   GREATER   CHICAGO
                      TABLE  4
    METALS  IN  RETURN  SLUDGE   OF
      DECEMBER   1972 - JUNE   1973
              Zn    Cd    Co    Cr   Fe    Ni    Pb
 DEC.
 JAN.
 FEB.
 MAR.
 APR.
 MAY.
 JUNE
 AVERAGE
1.33   0.01   0.22  0.02  5.6
0.75   0.00   0.16  0.02  3.4
0.53   0.00   0.14  0.01   1.7
0.83   0.01   0.12  0.01   3.1
1.18   0.01   0.24  0.02  5.8
0.79   0.01   0.20  0.01   4.5
0.99   0.00   0.25  0.01   5.4
0.91   0.01  0.19   0.01   4.2
0.00  0.59
0.00  0.36
0.01   0.27
0.02   0.38
0.03   0.62
0.00  0.38
0.01   0.46
0.01   0.42
AH values reported a* mg m«tal p«r gram return sludg* suspondod
 • elidi. Data r«pr»s«nts monthly av*rag*s of w*«kly garb samples.
                          492

-------
    Nitrification has been maintained without interruption since



June of 1972.  Sewage temperatures at the plant have been as



low as 45°F without any impairment in aiomonia removal.  Although



our current interest in single-stage nitrification lies primarily



in systems having shorter detention times, the data from the



Lemont WRP has demonstrated that the process, when operated



at long detention times, can consistently produce a well-nitrified



effluent.  As the flow to the plant increases due to expansion



of the sewered population, we will determine what operational



changes may be required to maintain effective nitrification.
                               493

-------
    Summary








    As described in the preceding sections, the MSDGC past



pilot plant experiences  in achieving nitrification of its



domestic wastewaters has been with the two-stage process.  Also,



the District's 50 mgd Salt Creek water reclamation plant which



is currently under construction is designed as a two-stage plant.



However, it should be pointed out that the MSDGC policy toward



nitrification at any future plants or in the expansion of present



plants is still not completely resolved.  Currently, the concept



of single-stage nitrification at all the major plants is being



tested on a pilot scale.  In particular, a pilot plant currently



under construction at West"Southwest will have a maximum flow



capacity of 26 mgd, (detention time, 5.5 hours)  with the return



sludge flow capability of 26 mgd.
                              494

-------
     Nitrification of a Hign Ammonia Content Sludge Supernatant
     by Biological Processes
    As part of its land reclamation and sludge recycle program,

the MSDGC has been barging anaerobically digested sludge to

Fulton County, Illinois for application to strip-mined lands to

promote row crop production and grazing.  Before the digested

sludge is spread on the land, it is held in large holding basins

or lagoons.  Since the sludge remains in the lagoons for a signi-

ficant period of time, much compaction of the digested solids

occur and a substantial layer of supernatant, which is relatively

low in suspended solids, is formed.  Because of the direct

influence of high nitrogen content on land demand, it was

imperative that the MSDGC develop methods for reducing the ammonia

content of the sludge lagoon supernatant (S.L.S.), since the

ammonia content of the S.L.S. constitutes up to 50% of the total

nitrogen content of the lagooned digested sludge.

    Basically, there were two alternatives for reducing the

ammonia content of the S.L.S.  Either the S.L.S.  could be barged

back to the West-Southwest Treatment Plant in Stickney, Illinois

or the S.L.S. could be  treated on site at Fulton County with

the effluent being discharged to the local waterways.

    The overall goal of the investigation was to pursue the

second alternative and determine the feasibility of biologically

treating S.L.S. for stream discharge.  Because of the small

amount of information available on the biological treatment of
                               495

-------
a high strength ammonia waste, particularly sludge supernatant,




it was of importance to initially establish the feasibility




of biologically nitrifying S.L.S.  Two methods of biological



treatment were evaluated:  namely, a conventional activated




sludge or biological slurry system and a system utilizing




partially submerged rotating discs.  The use of a rotating



disc system was investigated because of its potentially low



maintenance and operating costs.




    Throughout the study, S.L.S. from Fulton County was shipped



periodically by truck to theW-SW Treatment Plant where the



pilot tests were conducted.  As can be seen in Table 5_, which



lists the chemical characteristics of the S.L.S. which was used



in the study, S.L.S. is a high strength ammonia waste water




with the NH-j-N averaging 547 mg/1.  Since the oxygen required



to biologically oxidize ammonia to nitrates is 4.61bs 02/lb



NH3-N oxidized, the theoretical oxygen demand is considerable



and can be as high as 4050 mg/1 (when 879 mg/1 of NH3-N is



oxidized to nitrates).  It. can also be seen in Table 5_ that



there was on the average only about 3.3 Ibs alkalinity per Ib



of NH3~N contained in the S.L.S.




    Since the oxidation of NH3-N involves the theoretical




consumption of 1.2 Ibs of alkalinity per Ib of NH3-N oxidized,



the S.L.S. did not contain enough alkalinity to meet the demand.



This was important because the autotrophic bacteria which



oxidize ammonia require a pH of at least 6.5 - 7.0 in order to
                               496

-------
     METROPOLITAN  SANITARY   DISTRICT
            OF  GREATER  CHICAGO
                     TABLE  5
      CHEMICAL  CHARACTERISTICS
OF  SLUDGE  LAGOON  SUPERNATANT
         FROM  FULTON  COUNTY
CHEMICAL PARAMETER                AVERAGE    RANGE
pH                                          8.0-8.4
Alkalinity, mg/l                       1834     1215-2843
Total Kjeldahl Nitrogen (TKN), mg/l       703      465-975
NH3-N, mg/l                         547      292-879
N02-N, mg/l                         0.21     0.04-0.86
N03-N, mg/l                         0.40     0.26-0.74
Total Solids,mg/l                      1190      813-1462
Total Suspended Solids, mg/l            150      52-231
Volatilo Suspended Solids, mg/l            97       39-126
Total BOD                            64       28-121
Total COD                           753      345-1119
Total P04-P                          40.5     23.1-51.1
                      497

-------
function properly.  If the pH goes below 6.5, the rate of


oxidation drops off radically.  Therefore, throughout the


study, the pH was controlled in the range of 7.8 - 8.2 with


the addition of sodium carbonate.


    The rotating disc pilot system consisted of a semi-circular


fiberglass tank which was divided into four equal volume compartments


The tank was equipped with 2' diameter plastic  discs arranged


on a horizontally rotating shaft.  The total surface area


provided by the discs was 250 ft2.  The volume of the unit was


35 gallons, with the discs submerged 40% of the diameter.  Disc


rotational speed was maintained at 3 rpm for the duration of the


study.


    The slurry system consisted of a 50-gallon plexi-glas


aeration tank, which was separated into seven compartments to


simulate a plug-flow system, and a 6'  high clarifier which

                                          2
provided a maximum surface area of 2.25 ft .   Air was supplied


by diffused aeration through porous membranes.


    Before the continuous flow operation began, both units


were initially filled with S.L.S. diluted by 50% with tap water.


The bio-mass within each system was allowed approximately two


weeks of acclimation before continuous flow operation began.


The temperature throughout the study in both units was maintained


in the range of 22° - 28°C.


    As can be seen in Figures 1£ and 17, which show  the


performance of both the rotating disc system and the slurry
                              498

-------
   METROPOLITAN  SANITARY  DISTRICT  OF  GREATER  CHICAGO
                               FIGURE  16
                  PERFORMANCE OF THE  SLURRY  SYSTEM
 v  "'


I  -

jO  6-



I  *"

    a—
                                      -DETENTION TIME
             INFLUENT NH3-N LOADING
                  so  a 3


                  •4° JS

                  30 5^

                  10  E *ۥ
                     mx
                  10    M
     .-
     1-1
       (85) (70)
                   34567*
T
10
I    I     I
n    ia    13
                      Weeks of Continuous Flow Operation

-------
en
O
O
                METROPOLITAN  SANITARY  DISTRICT  OF  GREATER  CHICAGO
                                             FIGURE 17
                             PERFORMANCE  OF THE ROTATING  DISC  SYSTEM
                 14
-S3 10
 •"

'I  '

.2  *

 O  4-
 O
0  1-
                  H
             MJ  O1
                                                          •DETENTION TIME
INFLUENT NH3-N LOADING—i


                 ..jr*!**""**
O.S




0.3

0.2


•O.I
                                                    .f ^
                                                    a o
                                                                                     E  *?
                                                                  10    11   12    13
                                    Weeks of Continuous Flow Operation
                                  Performance of the Rotating Disc System

-------
system, respectively, the S.L.S. was highly amenable to



biological nitrification.  Except for the first two weeks of



operation, both systems performed extremely well through the



progressively higher ammonia loadings applied.  The average



effluent NH3-N at the highest loadings for the rotating disc



system and slurry system was 2.5 mg/1 and 2.0 mg/1, respectively.



Except for the first few weeks when some ammonia was stripped



in both units (as determined by a nitrogen balance), the



effluent N03-N and NO2-N generally exceeded the ammonia removed,



which indicated a high amount of nitrification and conversion



of organic nitrogen to NH3-N and subsequent oxidation to N02~N



and N03-N.  The overall total Kjeldahl nitrogen removal (TKN)



for both systems at the highest loading was approximately 99%.



Early in the study, there was some inhibition of the NO2-N



oxidation in both systems as the effluent N02-N generally was



much greater than the effluent NO3~N.  However, at detention



times of ten days and lower, the effluent NC^-N was generally



less than 1.0 mg/1.



    The air flow rate to the slurry system was controlled to



maintain a D.O.  of at least 1-2 mg/1 in each of the compartments,



The D.O. in the rotating disc system was at least 2.0 mg/1 in



each compartment, even at the highest ammonia loadings.  The



amount of Na;>CO3 required to maintain a pH of 7.8 to 8.2 in the



rotating disc system averaged about 3-4 Ibs of alkalinity



per Ib of NH4-N oxidized, while the slurry system averaged
                               501

-------
4 -5 Ibs of alkalinity per Ib of NHj-N oxidized.



    In the temperature range of the study (2^-28°). it can be



concluded that high rates of ammonia oxidation in S^L.S. can



be achieved by both the slurry and rotating disc system as long



as the pH is properly maintained with Na2CO3.  Further work is



being conducted to determine the effects of lower temperatures



on both processes.  Also, a better assessment of the effluent



quality in terms of BOD and suspended solids of both systems



at the colder temperatures will likewise be  investigated.
                             502

-------
                         REFERENCES
1.   Sawyer, C.N., and McCarty, P.L. Chemistry for Sanitary
         Engineers, Second Edition, McGraw-Hill Book Company.

2.   Advanced Waste Treatment and Water Reuse Symposium, Volume
         1, Pick Congress Hotel, Chicago, Illinois, February
         23 - 24, 1971.

3.   State of Illinois the Environmental Protection Agency,
         Water Pollution Regulations of Illinois, March, 1972.

4.   "Ammonia Removal from Agricultural Runoff and Secondary
         Effluents by Selected Ion Exchange", Robert A. Taft
         Water Research Center Report TWRC-5.

5.   Gulp, R.L., Gulp, G.L., Advanced Wastewater Treatment, Van
         Nostrand Reinhold Company, 1971.

6.   "Nitrification and Denitrification Facilities," report by
         Metcalf & Eddy, Inc. for Federal EPA Technology
         Transfer Program, Chicago, Illinois (November 1972).
                             503

-------
                 STORM AND COMBINED SEWER
                   ABATEMENT TECHNOLOGY
                   IN THE UNITED STATES
                     - AN OVERVIEW -
     Francis J.  Condon,  Supervisory Sanitary Engineer

           Municipal Pollution Control Division
             Environmental Protection Agency
            Office of Research and Development
                      Washington,  D.C.
                       Presented at
Third U.S./Japan Conference on Sewage Treatment Technology
                       Tokyo,  Japan

                      February 1974
                             504

-------
*•  Introduction




    The Office of Research and Development of the U. S. Environmental




Protection Agency is organized so that program responsibility to develop




new technology for treatment and control of water pollution caused by




urban runoff falls within two organizational units.  The Municipal




Pollution Control Division of the Washington Headquarters staff is




responsible for planning, coordinating and assessing the program.  The




Advanced Waste Treatment Laboratory in Cincinnati, Ohio, is responsible




for implementation.  There are, of co,urse, other activities within these




units but this seminar will be limited to urban runoff pollution abatement




technology.




    The following are the principal sources of runoff induced pollution




as viewed in our program activities:  combined sewer (domestic sewage




and runoff) overflows, sewered storm water discharges, sanitary sewers




surcharged by infiltration, treatment works or pump station bypass and




urban non-point or overland runoff.




    Given these sources it follows that the specific causes are precipita-




tion and snow melt resulting in hydraulic overload relief of combined waste-




water collection and transport networks, pollutants flushed from urban




surfaces and bypass of excess wastewater flows at treatment facilities




to prevent process upset.




    When the causes are considered in this context, it is evident that




remedial solutions must include elements of urban hydrology as well as




sanitary engineering.  The superimposing of urban hydrology on the usual




sanitary engineering solution methods broadens the scope of problem




definition and abatement approach.  Considering the situation in such a
                                     505

-------
manner enters into the realm of metropolitan water balance systems or the




total system concept.




    Consideration of the total system in problem definition and alternate




solution schemes is somewhat new to the practicing sanitary engineer in the




United States who traditionally views waste water treatment as the principal




means of water pollution abatement.  Treatment of foul water will always be




necessary but improved technology development and application in prevention,




reduction and control of hydraulic and pollutant factors must be given high




priority when addressing storm and combined sewer overflow pollution sources.




    Figure 1 is a schematic display of the total metropolitan hydrologic




system which must be examined in developing data and applying technology for




urban water quality improvement.  It is illustrative of the scope in cause




and effected uses which should be considered in metropolitan runoff pollution.




    Figure 1 may be used for outlining areas for which water quality and




quantity data must be obtained to assess relative significance or as a guide




to where applied research will have the most effect.




    For example, the conditions of the urban land surface effects the quality




and quantity of:  direct runoff (non-point), storm drainage discharge and,




where interconnected in combined systems, the normal domestic sewage flows.




Therefore, as a first cut in prevention one would evaluate the possibilities




and effectiveness of manipulating urban land surfaces in reducing water




pollution.




    The Figure also serves as an example of the need to apply the system




concept in the analysis, planning and implementation of a Research,




Development, Demonstration Program.
                                    506

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                                                               ATMOSPHERE
                                         PRECIPITATION
                                                                      EVAPOTRANSPI RATION
cn
o
    <
    <
    £
    o
    tc
     \

                                      URBAN LAND SURFACE
                                         MANIPULATED
                                                               DIRECT
                                                               RUNOFF
                                                                FLOW
                                                            AUGMENTATION
                                                                                                   INDUSTRIAL
                                                                                                     WATER
     SURFACE WATER
      MANIPULATED
ZONE OF
AERATION
t 1
	 J

H
CAPIl
R

.LARY
SE
                                                                                     SPRING
SEEPAGE

                                                                                            RECHARGE
                                                                                              WELLS
                                   STORM
                                   DRAINS
                                                                                                              WASTE-
                                                                                                              WATER
                                                                                                             SEWERAGE
                                                                                                                inf
                                         eltratio i
                                                                 ZONE OF SATURATION
                                                                     DEEP INTRUSION
                                                                                                                                       SURFACE
                                                                                                                                       OUTFLOW
                                                           EFFLUENT
                                                                                                                                        EXPORTED
                                                                                                                                         WATER
                                                                                                                                     GROUNDWATER
                                                                                                                                       OUTFLOW
               X INTERCONNECTED IN
                COMBINED SYSTEMS
                             URBAN HYDROLOGIC SYSTEM
                               (ADAPTED FROM:  "SUMMARY OF THE HYDROLOGICAL SITUXVTION IN LONG ISLAND. N.Y.. AS A GUIDE TO
                                              WATER MANAGEMENT ALTERNATIVES". BY O.L. FRANKE AND N.E. MeCLYMONDS. U.S.
                                              GEOLOGICAL SURVEY PROFESSIONAL PAPER 627F. 1972)
                                                                                       c

-------
    This last point is of importance.  The large majority of research and




development efforts and resources in the United States, and apparently other




Nations of the world, have been devoted to the development of tools for the




treatment of wastewaters.  Relatively little effort has gone into overall




problem solutions which include prevention and control.  Within our program




attempts are being made to change the thrust from tool development to storm




and combined sewer problem solution development.  That is, we hope to complete




preliminary National field measurement programs that when coupled with




performance data from categories of tools, i.e., liquid-solid separation,




flow control, rate attenuation, etc., will provide design criteria as




dictated by requirements of performance or by desired receiving water quality.




II. Problem Description




    In the paper entitled, "Municipal Pollution Control Technology in the




United States of America" presented in Tokyo by Mr. Frank M. Middleton during




the 1971 Conference, it was noted that the single dissimilarity between the




municipal wastewater treatment programs of Japan and the United States was




the trend in Japan of continuing to build combined sewer systems.  In




comparison, current construction in the United States is primarily separate




systems.




    There is evidence of some change beginning to take place in the United




States away from the trend of constructing separate systems.




    In cities where existing collection networks have portions which are




combined, consideration is now being given to continuing constructing




combined sewers as the collection network is expanded.  The pollution loads




generated in urban runoff and the possible future need to reduce this source




is the motivating force for the change in trend.
                                      508

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    An example is the recommendations from the recent comprehensive report




of the Department of Public Works of San Francisco.  This exhaustive




investigation determined that to attain the desired water quality in San




Francisco Bay, it would be necessary to treat a large portion of the urban




storm water runoff.  Therefore, one of the principal recommendations of the




report is to continue to construct combined sewers predicted on the control




and treatment of wet weather flows.




    To gain a perspective of the problem in the United States a brief




summary of the physical and pollutional aspects of the storm and combined




sewer discharges will be given.  Tables 1 and 2 give the magnitude with




respect to population distribution and length of sewers.




    In the combined interceptor sewers the ratio of wet-weather to dry-




weather capacity ranges from 1:1 to 8:1.  The median ratio is 4:1.  This,




however, is somewhat misleading in that the rain events over the urban areas




are .usually of the cell patterns and short, intense precipitation in a




catchment area will cause overflow at one interception point while unused




capacity is available in other portions of the system.




    Several of our projects have documented that rainfall intensities as




low as 0.01 in/hr  (0.025 cm/hr) cause overflow from combined sewers.  Further,




common rainfall intensities of 1.0 in/hr (2.5 cm/hr) will cause flow rates




of 50 to 100 times the dry-weather flow at the interception point.




   The incidence of overflow events for each relief point is about 30 per




year.  Consideration of an entire metropolitan area, however, yields a range




of 60 to 100 events per year for the entire combined collection network.  The




average duration of overflow is about 5 hours.  In storm sewer discharges the




average number of events per year is 95 with an average duration of 7 hours.
                                     509

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                                Table 1

             Number, Population and Area of U.S. Communities
                       Served by Combined Sewers
Population
Groups
50
25
10
5
1
1
over
,001 -
,001 -
,001 -
,001 -
,001 -
,00 and
104
100,000
50,000
25,000
10,000
5,000
less
Total
U.S.
1
1
6
9
132
201
432
,134
,394
,613
,874
Population
Number (in 1 ,000 'si
Served by Served by
Cmb. Sewers Cmb. Sewers
75
86
119
203
227
458
161
26
3
2
1
,261
,854
,385
,865
911
874
86
Area
) (in 1,000's)
Served by
Cmb. Sewers
Acres
1,423 -
472 -
313 -
337 -
214 -
235 -
35 -
Ha
576
191
126
136
867
955
142
.7
.5
                    19,780
    1,329
36,236
3,029  -  1
     Of the total  sewered population  in  the United States approximately 29
percent is served  by combined sewers.

     The breakdown in round figures  is:   unsewered 74 million, separate
sanitary 90 million, combined sewers  36  million.
Separate
Sanitary
      Table 2

     Combined
      Sewers
             Separate
               Storm
Mi 1es      Km

53,801    86,566
Miles     Km

56,132   90,316
           Miles      Km

           21,571    34,708
                                    510

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(Network = 120 events)




    There are 14,200 plus combined sewer relief points and an estimated 700




storm sewer discharge points.  In the combined portion 72% have an interval




diameter of 24 inches (61 cm) or less.  There are 10,000 plus regulators in




the combined networks.




    Another factor to be considered in examing the physical characteristics




of combined sewer systems is that there are many cross overs between separate




sanitary and combined networks which are unrecorded and that many storm




systems are laid at shallow depths above the separate sanitary lines with




frequent exfiltration from the storm sewers and infiltration into the




separate sanitary sewers.  Such infiltration and illegal inflow connections




result in many miles of sewers which are identified as separate to be, in




fact, acting as combined sewers.




    When determining the receiving water pollution loading from combined




sewer overflows, several considerations not normally applied to dry-weather




domestic flows must be taken into account.




    A summary is as follows:




    A.  Both strength and total mass emission of pollutants on an event basis




        be considered in determining receiving water degradation potential.




    B.  The characteristics and concentrations of the polluting parameters




        change with rate (cfs-1/sec), time from start of discharge and real




        time of occurrence.




    C.  The rate of polluting parameter strength decrease is less than the




        rate of hydraulic or flow increase, therefore, the total emission




        of pollutants increases as the overflow intensity increases.
                                     511

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    D.   There is,  under the more common conditions, little dilution of the




        slug load in the receiving water during the initial critical time




        period.   This includes flowing streams as well as lakes, bays and




        estuaries.




    E.   In flowing streams dissolved oxygen deficits are usually more severe




        at greater distances downstream of the overflow point source than the




        distance and severity during normal treatment works operation.   This




        is caused by the slug load reaction time, the decrease in reaeration




        rate due to increase volume in the stream, and increased flow rate.




    F.   The oxygen demanding characteristics of combined sewage cannot be




        quantified in the same manner as dry weather sewage.   For example,




        the heavy metals from the street flush portion inhibit the micro-




        biological action in the BOD analysis.  Therefore, the 600$ reading




        is not a valid indicator of oxygen demand potential in combined sewer




        overflows.  Additionally, oxidation of the heavy metals, which can




        occur at a high rate,  is masked in the standard BOD analysis.




    G.   There is greater differences in the vertical distribution of




        pollutants in overflow relief flows than in normal dry-weather flow.




        Sampling procedures are more critical in accurate determination of




        pollution loads.




    These observations apply to storm water discharges as well.




    Tables 3 and 4 indicating pollutant concentration and loads for combined




and storm sewage discharges are given for comparative purposes.
                                     512

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                             Table 3
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.
BOD,
mg/T
Ave.
200
135
25

100
60
180
120
200
115
153
129
55
119
165
49
71
COD
mg/1
Ave.
500
330
55

.
200
-
400
250
-
115
464
177
-
238
155
382
SS
mg/1
Ave.
200
80
15

—
100
1,051
470
1,100
295
274
458
244
434
125
68
622
Total
Col i form
MPN/100 ml.
5x10?
2x10'
1x1 (T

IxlO7
-
- 7
1x10
-
-
~ g
2x1 Ob
-

^A.Ug
3x1 06
3x10
                            Table  4
   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, D.C.
BOD.
Ave?
28
36
32
9.4
-
12
106
11
19
COD
Ave.
.
-
224
-
-
-
58
85
335
SS
Ave.
2,080
505
-
1,013
81
26
71
247
1,697
Total
MPN/100 ml
_
-
3x105
-
~c.
1x10*
8.10?
1x1 OJ|
6x1 0D
                              513

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    For comparison purposes the following generalizations with respect to




pollution loadings can be made although wide variations can exist at specific




locations.




    A.  For any given collection system the raw domestic sewage which is




        carried out of the combined sewers by excess flows is about 5 to 7




        percent of the total dry weather flow on an annual basis.  With




        respect to time, the accumulated overflow events total about 4% or




        14 1/2 days per year.




    B.  On an annual basis the pounds of BOD5 discharged in combined sewer




        overflows is approximately equal to the pounds discharged from a




        secondary treatment plant serving the combined collection area.




    C.  On an event basis the organic loads placed on the receiving water




        during combined sewer overflow are 8 to 12 times the secondary




        treatment plant effluent load.




    D.  Urban runoff is similar to dilute industrial wastewater in many




        respects.  Calculations indicate that a moderate to heavy storm over




        an urban area will wash more oxygen demanding load into the receiving




        water than the same area's raw sanitary sewage during the same period




        of time.




    The impact of storm generated pollution on receiving waters is difficult




to quantify with precision.  The relative significance of various runoff




pollution sources in a reach of water requires a long period of sampling




under a sufficient range of the primary variables.




    However, it does appear the myth of dilution can be put to rest.  The




high frequency, low intensity storms are the greatest offenders.  The runoff




volume is low so that with respect to the receiving water volume there is
                                     514

-------
little percent change.  But the pollutant concentrations are so high that




significant levels of change are noted in the receiving water.




    For example, rainfall intensities up to 0.4 in. (10 cm.) per hour




account for 98 of the average 120 runoff events per year but only 32 percent




of the total volume of runoff.  Yet these low intensity events account for




over 85% of the pollutant mass emission.




    Therefore, if there is a dilution factor it occurs only in the less




frequent long duration, constant precipitation rate storms.




    This is a brief outline of the extent, cause, source and incidence of




the stormwater runoff problem.  The one important and unanswered question is:




What ranking value iwth respect to cost effectiveness will we give the problem




relative to other sources of water pollution, e.g., industrial or municipal




treatment works?  This of course would assign the priority -of remedial




construction funding.  Attempts to resolve this question are currently




underway.




III.  Strategy for Research and Development




    The Federal Water Pollution Control Act Amendments of 1972 contains




sections which deal with technology research and development, urban runoff,




consideration in developing area wide plans, and permit conditions for




combined sewer overflows.  There are requirements for quantifying the




pollution of stormwater runoff.  There is, however, a large gap in current




construction funds for remedial hardware.  The relative significance of the




problem must be determined with a high degree of certainty before immediate




remedial funding allocations can be justified.




    Future corrective action, however, cannot be denied.  As the conventional




pollution sources of municipal treatment works and industrial plants are
                                   515

-------
brought under control, the significance of combined and stormwater discharges




will increase.  In many cases, the receiving water quality standards will not




be attained until these sources are reduced or eliminated.




    With the strong possibility of near future construction expenditures, it




would be well to review the strategy and tools developed for abatement.




    The formulation of the program strategy for research and development




activities was influenced by four elements.  These can be identified from




Figure 2.  They are:  (1) the requirements of the water pollution control




act, (2) the existing conditions, (3)  the level of technology practiced along




with the State-of-the-Art of the technology, and (4)  the funding available.




    Initially, the strategy of the program, which began eight years ago, was




to carry out full-scale demonstration projects of new and improved abatement




tools wherein design, performance, benefits and cost data would be developed.




The goals of this program have been partially realized.  Over the first few




years of the program emphasis was changed to other areas of environmental




pollution and fewer full-scale projects could be supported than had been




originally planned.  As feedback from demonstrations was obtained, the thrust




of the program changed,  as mentioned in the Introduction, to methods of




problem solution.




    However, there have been several pilot and bench top projects completed,




along with some full-scale demonstrations in development of novel or improved




tools.




IV.  Methods of Abatement




    A brief summary of selected projects grouped by principal methods as




shown in Figure 2 will be given.  It should be noted that many individual




projects cut across the category divisions and may incorporate two or more
                                     516

-------
                                    Figure 2
                                                                                          Storm and Combined Sewer
                                                                                          Pollution Control  Program
517

-------
methods.  However, for purpose of presentation, every project has been




assigned to one remedial method category.




    A.  Prevention or Input Management




             Fourteen projects have been completed in the category.  The




        projects include:   (1) quantity reduction (infiltration control),




        (2) quality improvement (deicing methods), (3) runoff rate atten-




        uation (porous pavements), and  (4) improved materials (electro-




        magnetic sub-surface profiling).




             The rational of the objectives in this remedial method grouping




        is best illustrated by referring to Figure 1.  As mentioned, urban




        land surface conditions effect the quality and quantity of non-point




        runoff, storm discharges and combined sewer overflows.  And, as




        importantly, they effect the time of concentration.  Therefore, any




        manipulation or improvement of the urban surface conditions which




        would reduce the volume of runoff or increase time of concentration




        or improve the runoff quality is considered a prevention method.




             An example of work in this area is the feasibility study




        entitled "Investigation of Porous Pavements for Urban Runoff Control".




        Various methods of construction to obtain permeable surface covering




        were examined in the investigation.  The material which indicated




        the highest possibility of success is porous asphaltic concrete




        roadways.




             The reason for selecting permeable street surfaces is that the




        urban street or roadway acts as a collector,  a transport pathway and




        generator of pollutants.  Its use, physical characteristics, location




        and method of construction makes a transition or hinge point between
                                     519

-------
    air,  land and water pollution.   Therefore,  a likely pollution control




    attack area is improvement in design,  method of construction and




    operation.




         Viewed in this fashion there are  many  benefits.   For example,  if




    a permeable surface is successful, part of  the runoff will enter the




    ground, reducing the volume and recharging  urban ground waters.   Part




    will flow through the base material and thus be rough filtered and




    the time of concentration will be increased.  Therefore, we may




    realize both prevention and control at a critical point in the




    hydrologic system.




         Based on the feasibility investigation there are two current




    demonstration projects, recently initiated, in which design and




    performance data are to be gathered on porous asphaltic parking lots




    and low design residential streets.  Other  projects are being




    considered in demonstration of improved curb and gutter design to




    facilitate street cleaning and swirl separators at inlets, in place




    of catch basins, to remove particulates (the majority of surface




    runoff pollutants)  by concentrating them in a relatively small




    percentage of the runoff volume followed with storage and treatment.




B.  Control or Flow Management




         Ten projects have been completed in this method of abatement.




    This is a somewhat misleading indication of the effort which has gone




    into the category.   Many of the effluent management or treatment




    projects have significant work in control of flows.  The projects




    listed here are totally dedicated to flow management.  The projects




    include:   (1) flow regulation (a manual of practice),  (2) flow routing
                                    520

-------
    (a dispatching system),  (3)  storage (deep tunnels),  and (4)




    instrumentation (maximizing in-system capacity).




         A capability profile will be given on the deep  tunnel concept,




    therefore, an example in this category will not be discussed.  However,




    a few words on the overall rational are in order.




         Flow control in combined sewer pollution abatement appears to




    be the most cost effective approach providing, of course,  there is




    adequate dry weather treatment facilities.  In the United States




    very few communities with combined sewers, in whole  or in part, know




    how their collection-transport systems react to runoff events.  In




    all of our problem definition and demonstration projects it has been




    found that either through flow routing, improved regulation or in-




    system storage, the rate of flow at a given relief point could be




    controlled to some degree thereby reducing the volume and incidence




    of raw sewage discharge.  As an added benefit, the efficiency of the




    treatment works can be markedly improved.




         Our conclusion is that a well designed sewer monitoring and




    sampling program integrated with in-depth rainfall and runoff




    monitoring to obtain accurate basic data for use in  the Storm Water




    Management Model will return many times over the original investment




    when an abatement scheme is to be chosen and construction started.




C.   Treatment Methods or Effluent Management




         The first groupings in this category are:   (1)  dual or multi use




    facilities,  (2) satellite plants or treatment at outfall points, and





    (3) in-stream treatment.
                                   521

-------
     Each of these groupings could be broken down into similar




specific processes such as:  physical, physio-chemical, bio-physical,




bio-chemical and chemical.




     The total of thirteen projects have been completed in this




category.  A brief summary of successful treatment modes developed




to pilot stage is as follows:




1.  Physical:




    (a) sedimentation and flow control (combined sewers)




    (b) screening, dissolved air flotation (combined sewers)




    (c) deep bed, dual media filtration (storm runoff and combined




        sewers)




    (d) swirl separation  (combined sewers and storm runoff)




    (e) microstraining and disinfection (combined sewers)




2.  Physio-Chemical:




    (a) powdered activated carbon (combined sewers)




    (b) coagulation - flocculation aids (combined sewers)




        Item (b)  is in conjunction with physical mode projects in




        (1)  above.




3.  Bio-Physical:




    (a) detention with bio action and physical separation, includes




        dual use (combined sewers)




4.  Biological:




    (a) dual use contact stabilization (combined sewers)




    (b) dual use trickling filter (combined sewers)




5. & 6.  Bio-Chemical and Chemical Modes have not been evaluated.
                                522

-------
         Although bio oxidation through storage lagoon aeration are




    among on-going projects, the operating data are not available.   In




    the 5 and 6 Subgroupings,  the completed work is principally in  methods




    of disinfectant generation which have been modified to suit combined




    sewer overflow treatment.   Two methods for generating sodium




    hypochlorite and one for chlorine dioxide have been developed.




         Abstracts of completed projects are in the Appendix.   A




    capability profile will be given on a dual use, biological




    demonstration facility.




         As a final observation in this category, it appears that dual




    use, in a physio-chemical or bio-physical mode of operation, is the




    most cost effective treatment scheme and that in-stream treatment is




    a poor risk for effectiveness.




D.  Combinations or System Approach




         In this category, the prevention, control and treatment methods




    are brought together and mathematical modeling is added to develop




    solution schemes, make cost effectiveness comparisons and examine




    alternate solution methods.  It is here where the total system




    approach is developed.  In all, six projects have been completed in




    this category.




         Our primary vehicle in approaching the total system concept is




    the Storm Water Management Model.  A capability profile will be given




    on this project.




         The remaining completed projects in this category are principally




    engineering investigations of urban areas which develop methods of




    examining alternate schemes and cost effectiveness comparisons.  From
                                   523

-------
        these, we hope to arrive at a uniform means of:  (1)  predicting




        pollution loads, (2) gathering and presenting evaluation data, and




        (3)  arriving at the true cost and receiving water benefits.




V.  Capability Profile:  Effluent Management




    A.  Dual Use Biological Treatment




             The concept of this project is to modify an existing activated




        sludge process in such a manner so as to provide contact stabilization




        for excess wet weather flows which are being bypassed at the plant to




        prevent process upset.  The following discussion and tables are




        extracted from a paper by Charles A.Hansen and Robert W. Agnew of




        Rexnord Company on an EPA demonstration project sponsored by the




        Municipal Pollution Control Division.




             Before construction of the demonstration system, the treatment




        train was grit removal, primary sedimentation, aeration (activated




        sludge), sludge mixing for anaerobic digestion, sludge thickening,




        clarification of the mixed liquor and chlorination.  The original




        plant treatment capacity was 23 MGD (1007 I/sec-).   The interceptor




        size at the plant wet well is 72 in. (183 cm.) with a 50 MGD




        (2190 I/sec)  capacity.  Bypasses of excess flows were frequent.




             A maximum design flow of 20 MGD (876 I/sec.)  was selected for




        the demonstration project.  The total wet weather capacity then being




        43 MGD (1890 I/sec.).




             The demonstration system was designed for integration with the




        original facilities.  A constant portion of activated sludge from the




        dry-weather operation is stored by balancing the biosolids reservoir




        inflow and outflow.  The stored material is used as a source of
                                     524

-------
                                  Figure 3
                             Kenosha, Wisconsin
                    Contact Stabilization Demonstration
                                Flow Diagram
o
3
CT
•o
O)
X
                                               Wet

                                                Well
                         Excess Flow
                         Wet Weather
                          Grit Basin

                         Stabilized
                           Sludge
       Biosolids Reservior
       Stabilization Basin
                  Normal  Operation
                                                          Primary Tanks
Contact Tanks
Aeration Tanks
                         Sludge Transfer
                                                 Digesters
                                                 Blowers and
                                               Sludge Thickener
                                                    Pump
                                                  Building
                                                  Chlorine

                                                   Contact
                                    -> Effluent
                                     525

-------
biological solids in the contact stabilization treatment of the




excess flows.  This mode of treatment is also identified as physical




adsorption, biosorption and sludge reaeration.  All refer to a




modification of the activated sludge process*




     Modification and additions to the existing plant hardware are




as follows:




1.  Installation of a 20 MGD (876 I/sec.) gas driven pump in the




    existing wet well and diversion chamber.  The pump delivers the




    wet weather excess flow to the demonstration system and can be




    used as standby for dry weather operation.




2.  An unused mixing basin was converted to a grit tank.  The tank




    is 56.5 ft. (17.23 m) long, 225 ft.  (68.62 m) wide and has a




    mean depth of 9 ft.  (2.74 m).  At a flow of 20 MGD  (876 I/sec.)




    the horizontal velocity is less than 0.2 fps (0.06 m/sec.).




3.  Construction of a contact and stabilization tank in one structure




    divided by concrete walls into four smaller tanks.  The contact




    section was designed to handle a maximum raw flow of 20 MGD




    (876 I/sec.) and a stabilized sludge flow of 5 MGD  (219 I/sec.)




    for a  15 minute contact period.  The contact section can be




    divided into two smaller units of different volumes to allow




    experiments in varying the contact time while the total flow




    remains constant.  This also provides like raw flow pollutant




    characteristics while comparing contact time effectiveness.  One




    unit of the contact tank has a volume of 164,000 gal.  (620,740 1) ,




    the second 80,500 gal. (304,792 1).  Therefore, by using the units




    either separately or simultaneously three effective volumes can
                               526

-------
    be made available.  The tank has a sidewall depth of 17.5 ft.




    (5.34 m).  Aeration is through a fixed air dispenser system along




    the bottom of one wall in each unit.  The system can deliver up




    to 3,750 scfm (106.12 cu m/min.).




4.  Following the contact section of the tank and divided by a




    concrete wall is the stabilization basin  (biosolids reservoir




    section).  This section is also divided into two parts so that




    various stabilization times may be evaluated.  Both units of this




    section are 30 ft.  (9.15 m) wide, 96 ft.  (29.28 m) long and 17.5




    ft. (5.34 m) deep.  Aeration is by eight  50 hp  (37.3 kw)




    floating mechanical surface aerators.  The arrangement allows




    for stabilization times of up to seven days.




5.  Construction of a new clarifier for use in both dry and wet




    weather flows.  The design surface overflow rate  (SOR) is




    1300 gpd/sq. ft.  (0.047 lps/m2) resulted  in a 140 ft.  (42.7 m)




    diameter, peripheral feed effluent clarifier.  The surface area




    is 15,400 sq. ft.  (1420.6 sq. m) and a volume of 1.4 million




    gal. (5.23 million  1).  During wet weather operation the




    clarifier is isolated from the dry weather plant.




6.  The necessary piping, pumps, valves and instrumentation are




    included.




     The system is kept in readiness by maintaining a biosolids




reservoir fed by the dry weather plant operation.




     When excess flows occur the raw flow pump automatically starts




and delivers the flows via the grit chamber to the contact section




where stabilized sludge from the biosolids reservoir is proportioned
                               527

-------
in.  At the same time the pump for transferring sludge from the new




clarifier to the stabilization section is put into operation.  The




air blower for the contact tank is also started at this time.  Once




the demonstration system is operating the sludge detention time




in the stabilization tank is short.  The time being dependent on the




flow rate entering the dry weather plant and the rate of transfer to




the contact section.  The sludge flow rate to the contact section is




a function of the rate of raw combined sewage flow through the




contact tank.  Meanwhile, at the new clarifier the flow from the dry




weather plant is diverted to the original clarifiers and the return




sludge line to the dry weather plant is shut, the return sludge line




from the new clarifier to the stabilization tank is opened.  The




clarifier then receives the feed from the contact-stabilization tank.




The necessary synchronism of blower and chlorine feed increase is




manually started.




     When the high flow condition has subsided the wet weather system




is manually taken out of service at the main control board.  After




shutting down the wet weather mode of operation, the start-up




procedures are automatically reversed and the plant returns to normal




dry weather operation.  The grit and contact tanks are then emptied




and the system made ready for the next event.
                                 528

-------
en
IX)
UD
                                                          Table  5

                                              Summary of Operating Conditions
Variable
Gal treated
Average flow rate
Duration of run
Return sludge
MLSS
Contact time
Reaeration time
Unit of Measure
mil gal
mgd
hours
% of raw flow
mg/1
minutes
hours
Stabilization time days
F/M
Stabilization
tank turnovers
Clarifier SOR
Clarifier
detention time
Clarifier
turnovers
Ib BOD/day
Ib MLSS

gpd/ft2
hours

Range
1.789-7.558
13.3-19.4
2.7-11.0
10-55'
975-5370
12.1-19.6
1.0-7.3
0.5-15
0.64-5.3
0.53-6.8
864-1257
1.3-1.85
1.7-8.2
Mean Metric
4.007 15.17X106L
16.6 727.2 L/sec.
5.8
37
3060
15.5
2.7
4.4 1.99 Kg
2.7
2.9
1078 305 cu m/min/ha
1.46
3.9

-------
                                Table  5
          1972 Removal Summaries 23 Events, 92 Mil Gal. Treated
                                   Arithmetic Mean              Weiqhted Mean
Total Solids
T.V.S.
Suspended solids
s.v.s.
Total 300
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Total Kjeldahl as M
Total P04 as P
Total coliform count/ml
Fecal cell form count/ml
 Raw flow sample taken after grit removal.
2
 Final sample taken prior to chlor(nation.
Raw1
706
270
325
126
115
27.6
121
25.4
1?,9
5.1

Raw
34,786
2,308
Final2
471
143
24.7
13.9
18.6
8.5
24.0
16.9
6.7
2.7
Geometric



Raw1
704
270
314
121
102
24.1
113
21.8
11.0
4.8
Mean



Final2
455
140
26.4
15.2
17.8
7.6
22.8
1 5 . 11
5.5
2.4

Fi nal 2
2,883
374
                                    530

-------
    The total construction cost for the system was $1.1 million.  The




capital cost breaks down to $917 per acre (.405 ha) served or $55,000 per




MGD (43.808 I/sec.).  Operating and maintenance cost cannot be determined




because all of the runs have been of experimental nature and no standard




procedure has been set.   Future plants can be constructed at lower cost




because provisions will not be necessary for operating at different levels




for each variable.




    The principal conclusions are:




        1.  The use of contact stabilization in treating excess flows at




            aerated activated sludge plants is feasible and reliable.




        2.  Removal efficiencies of SS - 90%, BOD5 - 80% and TOC - 79%




            can easily be maintained for excess flows.




        3.  Improved dry weather operation and performance can be realized




            at the existing plant.




        4.  The capital cost in dollars per unit of capacity can be lowered




            upon development of optimum variable operating ranges.




VI.  Capability Profile:  Storm Water Management Model




    The Storm Water Management Model and other associated work completed and




on-going in mathematical modeling are intended as prime tools for use in




applying the total system concept in selecting alternatives for water




pollution control.  Work is continuing on providing additional capability and




refinement of the SWMM and development of a family of models of varying




degrees of sophistication for use by planners, engineers and decision makers.




    This profile is extracted, with quotations, from a paper entitled "A Model




for Assessing Impact of Stormwater Runoff and Combined Sewer Overflows and




Evaluating Abatement Alternatives: by Harry C. Torno, U.S. EPA., Municipal
                                     531

-------
Pollution Control Division (RD-678),  Washington, D.C.  20460.  Copies of the




model program may be obtained by sending a blank 9-track 1600 hpi computer




tape to Mr. Torno and requesting the SWMM program.  Program documentation




will be furnished or is available separately.




    A users group has been established to exchange information and experience




on model applications and to act as a focal point for improvements.  Further




details are available from Mr. Torno.




    The entire SWMM is large.  There are over 10,000 FORTRAN statements and




it requires a large computer for reasonable execution.  For example, an IBM




360/65 with at least 512K bytes of core storage is required.  Some users have




executed the program on smaller computers (IBM 1130) by overlaying, reducing




size and number of COMMON areas and by using portions of the program.




    Using the rainfall (hyetograph) and system  (catchment, conveyance,




storage/treatment and receiving water) characteristics as inputs the SWMM




determines quality and quantity of runoff, routes the runoff through a




combined   (or separate system) with specified storage and treatment




facilities and operating policies, and thence into the receiving water, where




impacts are identified.  The output of the model consists of tables, hydro-




graphs and pollutographs of BOD, suspended solids, dissolved oxygen and




coliform.  These can be displayed for selected points within the system as




well as in the receiving waters.




    The SWMM consists of 5 blocks, or groups of subroutines.  They are:




    A.  EXECUTIVE Block - Provides control and  service functions.  All inter-




        facing between the four computational blocks takes place through this




        block.  The block includes a subroutine called COMBINE  (a network




        aggretation routine) which allows collection of two or more output
                                     532

-------
    data sets, and allows combination of different data sets and manholes




    into a single data set with one manhole.  This aids in modeling of




    large geographical areas.




B.  RUNOFF Block - Computes the storm water runoff and its associated




    pollution loadings for a given storm for each subcatchment and




    stores the results in the form of hydrographs and pollutographs at




    the inlets to the main sewer system.  Overland flow simulation is




    accomplished by a storage routing method using Manning's equation




    and the continuity equation.  Overland flow does not begin until




    depression storages are full.  Infiltration on previous areas is




    computed by Horton's exponential function, and is subtracted from




    water depth existing on the sub-catchment.  Gutter flows are treated




    as a succession of steady-state flows, with outing accomplished using




    Manning's equation and the continuity equation.  To use this block,




    the user must input the rainfall hyetograph and a discretization of




    the drainage basin into sub-basins of constant land from character-




    istics.  The location and chara-teristics of the gutters and pipes




    also have to be described.  In addition, the user must input street




    cleaning frequency and catchbasin data as well as the land use and




    other features of the different areas of the basin.




C.  TRANSPORT Block - Routes flows through the sewer system.  Prestorm




    conditions in the sewers are set up by computing dry-weather flow and




    infiltration and distributing them throughout the conveyance system.




    The Transport Block then routes the storm runoff (as determined by




    the RUNOFF Block), the dry weather flow  (DWF), and the water that has




    infiltrated into the system through the main sewer pipes, and through




    a maximum of two optional "internal" storage tanks.
                                   533

-------
         The routing scheme is based on a finite-difference solution of




    the St. Venant equations, in which normalized values of the flow and




    conduit cross-sectional area are used.  When a pipe is flowing full




    and inflow exceeds outflow, the excess (surcharge)  is stored at the




    upstream manhole.  The flows are routed to a maximum of five outlet




    points.  This block requires that the sewer system be discretized




    into pipe segments of constant size, slope, and type jointed by




    either manholes, control structures such as flow dividers, or




    "internal" storage tanks.  An "internal" storage tank is described




    by its size, shape, outlet device, and unit cost.   The outlet device




    can be either a pump specified to go on or off at a specified tank




    depth, a weir, or an orifice.  The outlet device is used to specify




    the operation policy of the storage tank.




         The DWF and quantity entering the sewer system are calculated




    by inputting to the model such parameters as daily and hourly




    pollution correction factors, land use and population of the




    subareas, and average market value of the dwellings in a subarea.




    If more exact data is available such as average BOD of flows, this




    can be used in place of some of the other data.




         Infiltration is calculated by estimates of base dry weather




    infiltration and groundwater and rainwater infiltration, and such




    parameters as average joint distance.  The use of the subroutines




    calculating DWF quality and quantity and infiltration is optional.




D.  STORAGE Block - Simulates the changes in the hydrographs and




    pollutographs of the sewage as the sewage flows through one optional




    special wastewater treatment facility.  The facility has to be
                                  534

-------
    located at one of the outfalls specified in the Transport Block.




    The treatment process is chosen by the user to consist of a sequence




    chosen from the following unit processes:  "external" storage (same




    as "internal" storage except that it is located adjacent to an outlet




    of the sewer system), bar racks, fine screens, dissolved air




    flotation, sedimentation tanks, microstrainers, high rate filters,




    effluent screens, swirl concentrators and chlorinators and other




    chemical dispensers.  The user can specify the sizes of the treatment




    processes or else can specify that the model is to select the sizes




    of the processes (except for "external" storage)  such that a certain




    user-selected percentage of the peak flow receives treatment.  The




    Storage Block also has the capability of calculating the capital,




    land, and operation and maintenance costs of the treatment processes




    chosen.  The user has the option of either specifying the unit costs




    or using default values provided by the simulation model.  The




    calculations in this block are based on the continuity equation.




E.  RECEIVING WATER Block - Takes output from TRANSPORT or STORAGE and




    computes the impact of the discharges upon the quality of the




    receiving water.  The receiving body of water is discretized by the




    user to consist of a network of nodes connected by channels.  An




    option in the program allows two parallel channels to be used between




    junctions, to aid in simulating receiving bodies such as marshes.




    Each channel is of constant surface and cross-sectional area.




    Boundary conditions can be specified as a weir (outfall from a lake)




    or some tidal condition.  The structure of the SWMM is schematically




    depicted in Figure 4.
                                   535

-------
                 INFILTRATION
                      3
                                            DRY WEATHER  FLOW
EXTERNAL
STORAGE


TREATMENT


TREATMENT
COST
                      ±
               RECEIVING WATER
                        FIG. 4
                   SWMM Structure

     The model was originally developed to consider only storm a no

combined sewer abatement alternatives.   It has become apparent that

the wet weather flows cannot be considered separately from the

conveyance and treatment of sanitary sewage.   This is brought into

focus when considering the effects of various discharges (municipal

treatment works, combined sewer overflows and industrial discharges)

upon receiving waters.  Modifications are now being made to include

dry weather treatment facilities in the SWMM and to increase the

capabilities for such pollutants as nitrogen, phosphorous,  oil and

grease.

     Model verification and refinement has been accomplished in

application to measured flow and analyzed water quality for catchments

in San Francisco, Cincinnati, Washington, Philadelphia, and

Lancaster, Pennsylvania.


     Access to digital computers for execution of complex mathematical

models is becoming more available to the engineer and such tools


should be used in examining abatement alternatives to water pollution

abatement.
                                536

-------
VII.  Summary

    In the next three years there will be several EPA demonstration projects

in which the evaluation phase will be completed.  These projects were

initiated as long as five years ago.  Therefore, for the immediate future

the program plan may best be described as an assimulation period.  The data

obtained from the full-scale facilities will be incorporated into data

matrices relating to cost effectiveness for use in developing problem solution

methods.  Consequently, the start-up of full-scale demonstrations will be

curtailed.

    The following tables are based on the data collected for a report now

in preparation*entitled "Urban Storm Water Management and Technology:  An

Assessment".

    The tables are skeleton outlines and summaries of the cost and performance

information collected which is pertinent to this paper.



                                    Table 7

                      Estimated Costs of Sewer Separation

                                               Estimated cost^ $/acre
    Regional  Costs                               Type 2^ (gravity)'
      New England                                     35,580
      Middle Atlantic                                 24,350
      South Atlantic                                  24,530
      Southern                                        16,720
      Midwest                                         10,710
      West                                             9,250
      National  average                                18,260

    a.   Adjusted to ENR = 2000.
    b.   Type 2 is constructing new storm sewers and using existing combined
        sewers for sanitary sewers.
    Note:   $/acre x 2.47 = S/hectare
     ^Published as Report EPA-670/2-74-040,  December  1974,
                                     537

-------
CO
c»
                                                       Table  8

                                    Sewer Separation Versus Conceptual Alternatives

                                            Capital costs?
Location, (REF.
Boston, Mass.
Bucyrus, Ohio
Chicago, 111.
Cleveland,
Ohio
Detroit, Mich.
Seattle, Wash.
Washington,
D.C.
) Separation
997,260,000
15,957,000
6,772,255,000
372,405,000
2,859,185,000
15,486,000
677,778,000
Alternative
779,692,000
9,220,000
1,322,378,000
111,842,000
2,859,000 1
8,185,000
353,333,000
a. Adjusted to ENR = 2000.
b. Ratio of separation cost to alternative cost.
c. Alternative costs are for first phases only and
Cost ratioD
1J3
1:7
5:1
3:3
,000:lc
i:9d
1:9
do not incl
Alternative
Deep tunnel
storage
Lagoon system
Storage tunnels
and quarries
Offshore stabil-
ization ponds
Sewer monitoring
& remote control
of existing com-
bined sewer stor-
age system
Computer controlled
in-sewer storage
system
Tunnels & mined
storage
ude future
                        total  system.
                    d.   Separation costs  are only for southwest and east central Seattle, while
                        alternative costs are for the total  combined sewer area.

-------
                                                   Table 9

                                   Summary of Storage Costs for Various Cities9
Location
Seattle, Wash.
Control and monitoring system
Automated regulator station

^inneapolis-St. Paul, Minn.
Chippewa Falls, Wis.
Storage
Treatment
en
£o Jamaica Bay, New York City, N.Y.
Basin
Basin and sewer
Humboldt Avenue, Milwaukee, Wis.
Boston, Mass.
Cottage Farm Stormwater
Treatment Station
Chicago, 111
Storage and tunnels
Treatment
Storage basins
Collection, tunnel, and
pumping0
Storage,
mil gal.

—
—
32.0
—

2.8
--


10.0
23.0
4.0


1.3

5,570.0
--
2,736.0

2,834.0
Capital cost, $

3,500,000
3,900,000
7,400,000
3,000,000

744,000
186,000


21,200,000
21,200,000
2,010,000


6,200,000

1,323,000,000
1,550,000,000
568,000,000

755,000,000
Cost per
acre,
$/acre

—
__
--
--

8,260
2,070


6,530
6,530
3,560


—

5,500
6,460
2,370

3,150
Storage
cost,
$/gal.

--
--
0.23
—

0.26
—


2.12
0.92
0.50


4.74k

0.24
--
0.28

0.27
Annual
Operation S
maintenance
cost, $

--
--
250,000
--

--
--


--
00
--


65,000

--
—
--

~~
a.  ENR = 2000.
b.  Includes pumping station, chlorination facilities, and outfall.
c.  Includes 193.1 km  (120 miles) of tunnels.
Note:   $/acre x 2.47 = $/hectare, $/gal. x 0.264 = $/liter, mil gal. x 3.785
= Ml

-------
                                   Table 10
                     Cost of Sedimentation Facilities3
Location of facility
          Capital cost,
 mgd          $/mgd
                      Annual
                   operation and
                 maintenance cost
                      $/mgd
Cambridge, Mass.
  Cottage Farm Storm-
  water Treatment
  Station
Columbus, Ohio
  Whittier Street
  Alum Creek
Milwaukee, Wis.
  Humboldt Avenue
New York, N.Y.
  Spring Creek-
  Jamaica Bay
 62.4

192
 43

192
480
100.000C

 32,000
 43,000

 10,500


 44,000
1,240
a.  ENR = 2000.
b.  Maximum capacity assuming 30-minute detention time.
c.  Includes pump station and screening facilities.
Note:   mgd x 43.808 = I/sec
                                      540

-------
en
                                                               Table 11

                                    Cost of Microstrainers and Ultrafine Screens for 25-Mgd Plants3
Loading
rate,
Influent gpm/
source sq ft
Micros trainers
Philadelphia, Pa.
Taft Institute
Hypothetical
Chicago, 111.
Ultrafine screens
Fort Wayne, Ind.

Storm 25
overflow
Activated 16
sludge
effluent
Sewage 5-10
effluent
Activated 6.6
sludge
ef f 1 uent

Storm
overflow
Modified Operation and
Capital capital maintenance cost
costb costc Annual 
-------
                                                  Table 12

                   Capital and Operation and Maintenance Costs for Biological Treatment3
Item
Location
Contact
stabilization,
activated
sludge
Kenosha,
Wisconsin
Trickling
filter
New Providence,
New Jersey
Rotating
biological
contactor
Milwaukee,
Wisconsin
Oxidation pond
Shelbyville and
Springfield,
Illinois
Plant capacity, mgd

Capital cost
(construction cost,
excluding land,
$/mgd

Operation and Maintenance
(annual cost assuming
250 hr/yr of operation),
<£/l,000 gal.
  20
78,300(
  4.8
68,000d
                         10.4
30,000
                          4.4
                  0.3 to 2.2b
43,800 to 55,000
a.  EMR = 2000.
b.  Equivalent capacity which is a pond with a 10-day detention time.
c.  Cost of pumps, aeration tanks, and final clarifier.
d.  Includes cost of plastic media filter, final clarifier, side piping, and electrical work.
e.  Approximate cost of dry weather flow.
f.  Cost only for Springfield, Illinois.
Note:  mgd x 43.8 = I/sec
       $/mgd x 0.0228 = $/l/sec
       $/l",000 gal. x 0.264 = <£/! ,000 1

-------
                                                  Table 13

                              Estimated Capital and Operation and Maintenance
                            Costs for Typical Physical-Chemical Treatment Plant
Capital costs, $
Location
Hypothetical
CAST a
Total
Annual
Hypothetical
PCTb
Total
Annual
South Lake
Tahoe, Calif.
Total
Annual
Albany, N.Y.C
Total
Annual
10 mgd
4,822,000
377,200
6,656,000
520,700
4,870,500
381 ,000
1,791,500
140,100
25 mgd
9,680,800
757,300
13,409,000
1,049,000
9,907,400
775,100
3,643,900
285,100
Operation and
maintenance costs,
<£/l,000 gal.
100 mgd 10 mgd 25 mgd 100 mgd
28,330,500
2,216,300 9.7 7.1 5.3
42,379,000
3,315,300 16.3 13.4 10.3
89,010,600
2,269,500 13.0 10.8 8.6
10,670,100
834,700 18.8 15.6 11.7
a.  CAST = conventional activated sludge treatment (for comparison only).
b.  PCT = physical-chemical treatment.
c.  Combined Sewer Overflow Treatment based on 100,000 gal/day pilot plant.
Note:  mgd x 43.808 = I/sec
       (f/1,000 gal. x 0.264 = tf/1,000 1

-------
                                                  Table 14


                                    Dissolved A1r Flotation Cost for 25 Mgda
Plant location
Construction cost
Including pre-
treatment devices"
Operation and
maintenance
Total cost,
£/l,000 gal.
Chemical cost
alone, 
-------
                                Table 15
            High Rate,  Deep Bed,  Dual  Media Filtration  Cost
                   Cleveland,  Ohio,  Pilot Facilities
                                                          Operation  and
                                                          maintenance
                                                          cost,  $/yr

                                                            44,000

                                                            55,000

                                                            98,000

                                                           129,000
a.  The cost data are based on an EMR of 2000.
b.  Based on 5 hour overflow event with only temporary  sludge  storage.
    Sludge handling cost not included.
Plant capaci
cu m/min
64
132
263
526
tyb
mgd
25
50
100
200
Capital9
cost, $
1,580,000
2,390,000
4,370,000
7,430,000
                                  545

-------
                                                 Table 16

                                  Examples of System Operation Controls
Location
Seattle
Wash.
Boston,
Mass.
Dallas,
2 Tex.
CTl
= San Francisco,
1 Calif.
Operation
scale
Full
Full
Full
Full
Operation
controlled
Overflow
quantity
Overf 1 ow
quality
Sewer
surcharge
Overflow
quality
Monitoring devices
Level sensors, rain gages,
wind gages, automatic sam-
plers, telemetry units,
computer, position sensors.
Level sensors, automatic
sampler, Dall tube, re-
sidual chlorine analyzer.
Level sensor, magnetic
flowmeter, temperature
probe, computer.
Magnetic flowmeters, level
probes, differential pres-
sure sensor.
Control devices
Gate regulators, tide
gates, pumping stations.
Pumping station, sodium
hypochlorite feeder, gat
regulators.
Polymer injection feeder
Polyelectrolyte feeders,
solids pump, bypass
gates, dissolved air
Mt. Clemens,
Mich.
Full
Milwaukee,
Wis.
Minneapolis,
Minn.
Full
Full
Overflow      Magnetic flowmeters,  level
quality       probes, automatic samplers,
              differential  pressure
              sensors.
Overflow      Level  sensors,  automatic
quantity      samplers,  magnetic
              flowmeters.

Overflow      Automatic  samplers,  rain
quantity      gages, computer,  pressure
              sensors.
flotation units.

Pumping stations, aerated
lagoons, microstrainer,
pressure filters,
chlorine-chlorine dioxide
feeders.

Mixers, chlorinators, bar
screen, detention tank.
Fabridam regulators, gate
regulators.

-------