EPA 600/9-77-027
            PROCEEDINGS

       5th UNITED STATES/JAPAN
            CONFERENCE ON
    SEWAGE TREATMENT TECHNOLOGY

              TOKYO, JAPAN
             APRIL 18-22, 1977
    U.S. ENVIRONMENTAL PROTECTION AGENCY

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                RESEARCH REPORTING SERIES

Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology.  Elimination of traditional grouping  was  consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
      1.  Environmental  Health Effects Research
      2.  Environmental  Protection Technology
      3.  Ecological Research
      4.  Environmental  Monitoring
      5.  Socioeconomic Environmental Studies
      6.  Scientific and Technical Assessment Reports (STAR)
      7.  Interagency  Energy-Environment Research and Development
      8.  "Special" Reports
      9.  Miscellaneous Reports
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.

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                                    EPA-600/9-77-027
                                    DECEMBER 1977
               PROCEEDINGS
FIFTH UNITED STATES/JAPAN CONFERENCE  ON
       SEWAGE TREATMENT TECHNOLOGY
            APRIL 18-22,  1977
              TOKYO, JAPAN
   OFFICE OF  INTERNATIONAL  ACTIVITIES
 OFFICE OF WATER AND  HAZARDOUS  MATERIALS
         WASHINGTON,  D.C. 20460

   OFFICE OF  RESEARCH AND DEVELOPMENT
         WASHINGTON,  D.C. 20460
         CINCINNATI,  OHIO 45268
  U.S. ENVIRONMENTAL  PROTECTION AGENCY
   OFFICE OF RESEARCH AND DEVELOPMENT
         CINCINNATI,  OHIO 45268

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                 DISCLAIMER
These Proceedings have been reviewed by
the U.S. Environmental Protection Agency
and approved for publication.  Approval
does not signify that the contents necessarily
reflect the views and policies of the U.S.
Environmental Protection Agency, nor does
mention of trade names or commercial products
constitute endorsement or recommendation for
use.
                      11

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                               FOREWORD
     Environmental improvement is a worldwide need.  Maintaining clean
water supplies and managing municipal and industrial wastes is a vital
element of a quality environment.

     The participants in the United States-Japan cooperative project
on sewage treatment technology have completed their fifth conference.
These conferences, held at 18-month intervals, give the scientists and
engineers of the cooperating agencies an opportunity to study and com-
pare the latest practices and developments in the United States and
Japan.  These Proceedings of the Fifth Conference comprise a useful
body of knowledge on sewage treatment, which will be available not only
to Japan and the United States but also to any nation of the world
which may wish to have it.
                                       las M. Co
                                      inistrator
Washington, D.C.
                                  Ill

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                    CONTENTS
FOREWORD
JAPANESE DELEGATION                          vi
UNITED STATES DELEGATION                    vii
JOINT COMMUNIQUE
JAPANESE PAPERS
UNITED STATES PAPERS
                        v

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              JAPANESE DELEGATION
K.  INOMAYE
  Team Leader - Director, Department of Sewerage
  & Sewage Purification, Ministry of Construction

S.  TAKAHASHI
  Head, Planning Division, Department of Sewerage
  & Sewage Purification, Ministry of Construction

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

T.  HAYASHI
  Head, Water Quality Control Division, Water Quality
  Bureau, Environmental Agency

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

H.  FUJII
  Senior Advisor, Sewerage Bureau, Tokyo Metropolitan
  Government

K.  TANI
  Head, Construction Division, Sewage Works Bureau,
  Osaka City Office

S.  MIYAKOSHI
  Head, Construction Division, Sewage Works Bureau
  Yokohama City Office

DR. T. KUBO
  Co-Chairman - Vice President, Japan Sewage Works
  Agency
                         VI

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              UNITED STATES DELEGATION

FRANCIS M. MIDDLETON
  General Chairman of the Conference and Team Leader
  Senior Science Advisor/
  Municipal Environmental Research Laboratory
  U.S. Environmental Protection Agency
  Cincinnati, Ohio 45268

DR. CARL A. BRUNNER
  Chief, Systems & Engineering Evaluation Branch
  Wastewater Research Division
  Municipal Environmental Research Laboratory
  U.S. Environmental Protection Agency
  Cincinnati, Ohio 45268

DR. ROBERT L. BUNCH
  Chief, Treatment Process Development Branch
  Wastewater Research Division
  Municipal Environmental Research Laboratory
  U.S. Environmental Protection Agency
  Cincinnati, Ohio 45268

ROBERT S. BURD
  Chief, Water Division, Region X
  U.S. Environmental Protection Agency
  Seattle, Washington 98101

FRANKLIN D. DRYDEN
  Head, Technical Services Department
  Los Angeles County Sanitation Districts
  Whittier, California 90607

WILLIAM J. LACY
  Principal Engineering Advisor
  Office of Research & Development
  U.S. Environmental Protection Agency
  Washington, D.C. 20460

J. LEONARD LEDBETTER
  Director, Water Protection Branch
  Department of Natural Resources
  Environmental Protection Division
  Atlanta, Georgia 30334

THOMAS P. O'FARRELL
  Sanitary Engineer,  Water Program Operations
  Office of Water and Hazardous Materials
  U.S. Environmental Protection Agency
  Washington, D.C. 20460

                         vii

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              UNITED STATES AND JAPAN
          DELEGATES TO THE 5TH CONFERENCE
U.S. DELEGATES CONFERRING ON TREATMENT TECHNOLOGY
 WITH MR. R. OKUDA, GOVERNOR OF NARA PREFECTURE
                       Vlll

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                             -t*
                            ../      r-i
     UNITED STATES  TEAM  INSPECTS
DEEP TUNNEL STORMWATER CONTROL PROJECT
            OSAKA, JAPAN
        UNITED STATES TEAM TOURS
  ADVANCED WASTE TREATMENT PILOT PLANT
              KYOTO, JAPAN
                  IX

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VIEWING A NEW SEWAGE  TREATMENT PLANT
              NARA,  JAPAN
                PILOT PLAIT. KYOTO
               IM ,',
                 ! '• ,
                            •i
DR. M. KASHIWAYA AND DR.  K. MURAKAMI
  MINISTRY  OF CONSTRUCTION, JAPAN

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                             JOINT COMMUNIQUE
                      FIFTH US/JAPAN  CONFERENCE  ON
                       SEWAGE  TREATMENT  TECHNOLOGY

                      TOKYO/  JAPAN  APRIL 28,  1977
1.   The Fifth United States - Japan Conference on Sewage Treatment
     Technology was held in Tokyo,  Japan from April 26 ~ 28, 1977-


2.   The United States Delegation headed by Mr. F. M. Middleton, Senior
     Science Advisor, Municipal Environmental Research Laboratory, U.S.
     Environmental Protection Agency,  Cincinnati, Ohio, was composed of
     six USEPA officials and two local government officials.


3.   Mr. K. Inomaye, Director, Department of  Sewerage and Sewage Purifi-
     cation, Ministry of Construction, was Head of the Japanese Delegation,
     other delegation members were three national government officials, two
     Japan Sewage Works Agency officials and  three local government officials.


4.   The Chairmanship for the Conference was  shared jointly be Mr. F. M.
     Middleton and Dr. T. Kubo, Vice President, Japan Sewage Works Agency.


5.   Prior to the Conference, the United States Delegation visited the Toba
     Sewage Treatment Plant, Kyoto;  the Advanced Waste Treatment Pilot Plant,
     Otsu; the takagi Tannery Wastewater Treatment Plant, Himeji; the Yamato
     River Purification Center, Nara;  the Kawamata Sewage Treatment Plant and
     the Nakahama Sewage Treatment Plant, Osaka; the Morigasaki Sewage Treatment
     Plant, Tokyo and the South Sewage Treatment Plant, Yokohama.  Each field
     visit involved the subject matter discussed in the Japanese side papers
     presented at the Conference so that the  Conference may promote vigorous
     discussion more in detail.


6.   During the Conference the United States  Delegation presented a series
     of papers on the topics of Control of Non-point Source Pollution, Use
     of New Technology in the EPA Construction Grant Program, Georgia's Water
     Quality Control Program, Federal-State-Regional Participation in the
     Development of a Wastewater Management Plan, Regional Domestic Waste-
     water Management, Urban Run-off Pollution Control Technology, Wastewater
     Reuse, Industrial Wastewater Pretreatment and Joint Treatment, Criteria

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     and Assessment of Waste Treatability,  Biological, Nitrogen and
     Phosphorus Control, and Water Reclamation Technology.


7.   The Japanese side described Industrial Wastewater Control  into
     Public Sewers, Recent Topics in Water Pollution Control in Japan,
     Storm and Combined Sewer Overflows, Regeneration of Granular Acti-
     vated Carbon, Deep Aeration Tanks, Upgrading Existing Plant  by
     Chemical Addition to Aeration Tanks, Rapid Sand Filtration Process
     for Tertiary Purpose.  Papers on Sludge Disposal and Automatic  Water
     Quality Monitoring Equipment were presented at the Conference as an
     interim report of Joint Research Works between the United States and
     Japan under the Joint Agreement of the US/Japan Conference on Sewage
     Treatment Technology.


8.   Each presentation was followed by lively discussions from both  sides.


9.   Recent personnel exchanges include a  short visit to Japan by Mr. J. T.
     Rhett and Mr. M. B. Cook, USEPA, Washington, D.C. to investigate insti-
     tutional structures in the field of water pollution control in  Japan.
     Mr. F. M. Middleton visited  Japan to  discuss progress  of joint  research
     works and the program for the Fifth Conference.  Mr. K. Tanaka  and Mr.
     S. Hiromoto, Japan Sewage Works Agency, are planning to spend several
     months in the United States  in 1977 to study plant design and operation,
     and urban run-off pollution  control technology respectively.


10.  In addition to the Conference the Seminar was opened to about 200
     members of the Japan Sewage  Works Association on the subjects of the
     United States presentations  during the Conference.


11.  The Conference concluded that the technology exchange  program including
     the Conference was fruitful  to both sides in exchanging knowledge and
     experience and the Delegations agreed to  seek to explore more effective
     cooperation in the field of  research  works and that the personnel exchange
     program should be continued.


12.  It was proposed by the United States  side that the Sixth Conference
     should be held in the United States,  about October 1978.

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                          FIFTH US/JAPAN CONFERENCE
                                     ON
                         SEWAGE TREATMENT TECHNOLOGY
                                PAPER NO,  1
RECENT PROGRESS IN INDUSTRIAL WASTEWATER
CONTROL DISCHARGED INTO PUBLIC SEWER
RECENT TOPICS IN WATER POLLUTION CONTROL
IN JAPAN
             APRIL 26-28,  1977
               TOKYO,  JAPAN
          MINISTRY OF CONSTRUCTION
            JAPANESE GOVERNMENT

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RECENT PROGRESS IN INDUSTRIAL WASTEWATER CONTROL
DISCHARGED INTO PUBLIC SEWER 	  5
      S.  Takahashi, Ministry of Construction

RECENT TOPICS IN WATER POLLUTION CONTROL IN JAPAN	  28
      T. Hayashi, Environmental Agency

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      RECENT PROGRESS IN INDUSTRIAL WASTEWATER CONTROL
                   DISCHARGED INTO PUBLIC SEWER
1.   Reasons for Revision of the Sewerage Law	   6
2.   Summary of Revision in the Sewerage Law  	   8
  2.1    Introduction of Direct Penalty System	   8
  2.2    Introduction of a Prior Checking System	16
    2.2.1   Notification of Construction of Specified Facilities	16
    2.2.2   Orders for Modification of Plans 	17
  2.3    Introduction of Improvement Order System  	17
3.   Present State of Controls on Factory Effluent	17
  3.1    Present State 	17
    3.1.1   Number of Specified Factories	17
    3.1.2   Types of Specified Factories 	19
    3.1.3   Installation State of Pre-Treatment Facilities	22
    3.1.4   Surveillance on Factory Effluent	;	22
  3.2   Aid System for Construction of Pre-Treatment Facilities	25
  3.3   Publication of Guidance Manual	25

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RECENT  PROGRESS IN  INDUSTRIAL  WASTE WATER
CONTROL DISCHARGED INTO PUBLIC SEWER
1.   REASONS FOR REVISION OF THE SEWERAGE LAW
    The public sewerage system is indispensable as a facility not only for the im-
provement  of the living  environment but also for the maintenance of the water
quality of the public water bodies,  and therefore the improvement of the public
sewerage system is urged. However, such an improvement would not fully serve its
purpose, if the effluent from households and factories did not flow into the public
sewerage system and remained on the ground surface or continued to run along the
conventional open sewers.
     For this reason, the  Sewerage Law provides that as the public sewerage system
is opened for public use, all sewage in the relevant drainage area must be discharged
into the public sewerage system with the exception of the effluent whose direct dis-
charge into the  public water  bodies is approved by  the  general manager of the
public sewerage system. The Law also provides that the water quality of the effluent
discharged from the public sewerage system to rivers and other public water bodies
must meet  technical standards (Table 1) as specified under Article 8 of the Sewerage
Law.
    Therefore, it is the general principle that the following type of effluent dis-
charged from factories in the drainage area is treated at their source to meet certain
standards.  The effluent subject to the treatment is one that could either disrupt the
functions of sewerage facilities or damage the facilities or one that could make it dif-
ficult for the water quality of the effluent discharged from the final treatment facili-
ties to meet technical standards as provided under Article 8 of the Law.

                      Table 1  Standards for Effluent Quality
^"~~~~-^-^^^ Item
Classification ~-^^_^
Treatment of sewage by high-rate
trickling filter process, modified
activated sludge process and other
processes with similar efficiency.
Treatment of sewage by high-rate
trickling filter process, modified
activated sludge process and other*
processes with similar efficiency
Treatment of sewage by sedimen-
tation process
Other
Hydrogen-Ion
Concentration
(Hydrogen
Exponent)
5.8-8.6
5.8-8.6
5.8-8.6
5.8-8.6
Biochemical
Oxygen Demand
(mg/£ in
five days)
Less than 20
Less than 60
Less than 120
Less than 150
Amount of
Suspended
Solids
(mg/fi)
Less than 70
Less than 120
Less than 150
Less than 200
No. of
Bacteria Coli
(No./cm')
Less than 3000
Less than 3000
Less than 3000
Less than 3000
Figures were calculated by the procedures provided for in the Ordinance of the Ministry of Construction and
the Ordinance of the Ministry of Health and Welfare.

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                               Table 1  (Continued)
Substances
Cadmium and Its Compounds (Cd)
Cyanide Compounds (CN)
Organic Phosphorus Compounds
(Parathion, Methyl Parathion, Methyl
Demeton and EPN only)
Lead and Its Compounds (Pb)
Chromium (VI) Compounds [Gr (VI) ]
Arsenic and Its Compounds (As)
Total Mercury (Hg)
Alkyl Mercury Compounds
PCB
N-hexane Extracts

Phenols
Copper (Cu)
Zinc (Zn)
Dissolved Iron (Te)
Dissolved Manganese (Mr.)
Chrome (Cr)
Fluorine (F)
Permissible Limits
0.1 mg/E
1 mg/6
1 mg/E

1 mg/C
0.5 mg/E
0.5 mg/E
0.005 mg/E
Not detectable1
0.003 mg/E
5 mg/E (mineral oil)
30 mg/E (animal and vegetable fats)
5 mg/E
3 mg/E
5 mg/E
10 mg/E
10 mg/E
2 mg/E
15 mg/E
     In reference to controls on the inferior sewage discharged by factories or es-
tablishments that could disrupt the functions of sewerage facilities, damage them or
aggravate  the effluent quality of the final treatment facilities, the  Sewerage Law
before revision provided under Article  12 that the general manager of the public
sewerage system under relevant regulations could order factories and other establish-
ments to build pre-treatment  facilities or take other necessary measures. Standards
for the installation of pre-treatment facilities were to be instituted by city, town or
village authoritie's  regulations in accordance with the standards as  prescribed by
Cabinet Order (Table 2).
     In this  case, the standards provided by the regulations were the minimum re-
quirements to maintain the structure and  functions of the public sewerage system
and  conform the water quality of the effluent to the technical standards provided
under Article 8 of the Law, and unduly obligations must not be imposed on the user
of the public sewerage system.
     However,  it was  pointed out that under the Sewerage  Law before revision,
guidance for the installation of sewage pre-treatment facilities tended to be delayed
due to the following reasons.
  a.  The general manager  of the public sewerage system was  obliged to order the
violator of the regulations to install pre-treatment facilities,  but the penalty pro-
visions were  not applied unless he disobeyed the order given.  The Law had no pro-
visions for the so-called "direct penalty  system" in which the  violator of the regu-
lations is punished immediately upon the revelation of his violation.
  b.  The Law provided no prior checking system as to  the construction or reno-
vation of facilities that could discharge inferior sewage.
                                        7

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                       Table 2 Standards of Regulation Concerning
                               Installation of Pre-treatment Facilities
Substances
Temperature
pH
BOD
SS
N-hexane Extracts
Mineral Oils
Animal and Vegetable Fats
Consumption of Iodine
Phenols
Cyanide Compounds (CS)
Alkyl Mercury Compounds
Organic Phosphorus Compounds
Cadmium and Its Compounds Cd)
Lead and Its Compounds (Pb)
Chromium (VH Con^JoundSLCr (VI)j
Arsenic and Its Compounds (As;
Total Mercury (Hg)
Chrome (Cr)
Copper (Cu)
Zinc (Ziv)
Dissolved Iron (Fe)
Dissolved Manganese (Mn)
Fluorine (?)
PCB
Permissible
Limits
45° C
5-9
600 mg/e
600 mg/2
5 mg/2
30 mg/e
220 mg/2
5 mg/e
1 mg/e
ND
1 mg/C
0.1 mg/e
1 mg/C
0.5 mg/e
0.5 mg/C
0.005 mg/C
2 mg/B
3 mg/C
5 mg/e
10 mg/e
10 mg/e
15 mg/C
0.003 mg/e
                          With respect to sanitary sewage discharged from
                        facilities used for manufacturing and gas supplying
                        business, the standards can be tightened up to those
                        at the table below, if it is recognized that the total
                        amount of sanitary sewage from them  is equivalent
                        to more than  one-fourth of sanitary sewage to be
                        treated at the  treatment facility, that it will not be
                        sufficiently diluted by other sanitary sewage before
                        reaching the treatment facility or that there is any
                        other justifiable reason.
Substances
Temperature
PH
BOD
SS
Permissible Limits
40° C
5.7-8.7
300 mg/C
300 mg/C
     As a result,  the Law was revised to improve on  the  above-mentioned points,
strengthen  controls on  the effluent from  factories or establishments and thus con-
tribute to the maintenance of the water quality of the public water bodies.
2.   SUMMARY  OF REVISION IN THE SEWERAGE  LAW
2.1    INTRODUCTION OF DIRECT PENALTY SYSTEM
     Under  the revised  Sewerage Law, provisions less effective than the Water Pol-
lution Control  Law were improved, and a  new provision  was introduced to prevent

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the discharge  of the sewage whose water quality does not  meet specified legal
standards.  Violations, including accidental violations, are now subject to immediate
punishment on the revelation of their violations without taking supervisory action
for them.  Thus the revised Law has adopted the so-called "direct penalty system."
     This  new provision, as in the Water Pollution Control Law, is applied to facto-
ries  or  establishments  which  operate  specified facilities (as designated under the
Water Pollution Control Law as facilities that could discharge inferior waste water —
Table 3).  But its application  excludes kitchen  facilities,  washing facilities and
bathing facilities  (not using water from hot springs) of hotel business and the final
sewerage treatment facilities.

                            Table 3 Specified Facilities

(1)   MINING AND COAL  WASHING
      (a)  ore separation facilities,   (b) coal dressing facilities,   (c) neutralization
      and sedimentation facilities of mine water,     (d)  solids separation facilities
      from water used for digging.
(l)-2 LIVESTOCK BREEDING
      (a)  pig  shed facilities (excluding the facilities installed in the shed with the
      total area of less than 50 m2)
      (b) cattle shed facilities (excluding the facilities installed in the shed with the
      total area of less than 200 m2)
      (c)  horse shed facilities (excluding the facilities installed in the shed with the
      total area of less than 500 m2)
(2)   MEAT PACKING AND POULTRY PROCESSING
      (a)  initial  preparation facilities,   (b)  washing facilities,    (c) cooking facili-
      ties.
(3)   SEA FOODS MANUFACTURING
      (a)  initial  preparation facilities,    (b) washing facilities,   (c) dehydration
      facilities,   (d) screening facilities,   (e)  cooking facilities.
(4)   CANNED AND FROZEN VEGETABLES AND FRUITS MANUFACTURING
      (a)  initial  preparation facilities,   (b) cleaning facilities,    (c) pressing facili-
      ties,   (d)  cooking facilities.
(5)   MISO, SOY-SOURCE, EDIBLE AMINO ACID, GLUTAMIC ACID, VEGE-
      TABLE SOURCES AND VINEGAR MANUFACTURING
      (a)  initial  preparation facilities,    (b) cleaning facilities,   (c) boiling facili-
      ties,    (d)  concentration facilities,   (e)  finishing facilities,   (f)  straining
      facilities.
(6)   WHEAT FLOUR MANUFACTURING
      (a)  washing facilities.
(7)   SUGAR MANUFACTURING
      (a)  initial  preparation facilities,     (b)  washing facilities,    (c)  filtration
      facilities,   (d) separation facilities,   (e) refining facilities.
(8)   BAKERY  AND CONFECTIONARY
      (a)  bean-jam processing facilities.

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                                                          (c)  pressing
                                                        (c) separation
(9)   RICE CAKE AND MALT MANUFACTURING
      (a) washing facilities.
(10)  SOFT DRINK MANUFACTURING AND BREWERY
      (a) initial preparation facilities,     (b) cleaning facilities,    (c) extraction
      facilities,    (d) straining facilities,     (e)  boiling  facilities,    (f) stilling
      facilities.
(11)  FEED STAFF AND ORGANIC  FERTILIZER MANUFACTURING
      (a) initial preparation facilities,      (b) washing facilities,     (c) pressing
      facilities,    (d) vacuum concentration facilities,     (e)  water bushing de-
      odorization facilities.
(12)  OIL  AND FAT MANUFACTURING
      (a) initial preparation facilities,      (b) washing facilities,
      facilities,   (d) separation facilities.
(13)  YEAST  MANUFACTURING
      (a) initial preparation facilities,     (b) washing facilities,
      facilities.
(14)  STARCH MANUFACTURING
      (a) soaking facilities,     (b) washing facilities,     (c)  separation facilities,
      (d) waste pits.
(15)  DEXTROSE MANUFACTURING
      (a) initial preparation facilities,     (b) filtration facilities,
      facilities.
(16)  NOODLES  MANUFACTURING
      (a) boiling facilities.
(17)  BEAN FOODS MANUFACTURING
      (a) boiling facilities.
(-18)  INSTANT COFFEE MANUFACTURING
      (a) extraction facilities.
(19)  TEXTILE INDUSTRY
      (a) scouring facilities,    (b) by-product processing facilities,
      facilities,    (d) finishing facilities,    (e) silket machine,
      facilities,   (g) dyeing facilities,   (h) chemical treatment facilities.
(20)  WOOL SCOURING AND WASHING
      (a) wool scouring and washing facilities,  (b) carbonizing facilities.
(21)  SYNTHETIC TEXTILE MANUFACTURING
      (a) spinning facilities,    (b) chemical treatment facilities,
      facilities.
(22)  CHEMICAL FINISHING OF WOODS
      (a) wet barker,   (b) chemical soaking facilities.
(23)  PULP AND PAPER MANUFACTURING
      (a) soaking,    (b) wet  barker,    (c) chiper,  (d) digester,
      later  for  digester waster,    (f) chip refiner and pulp refiner,
                                                          (c)  refining
                                                          (c) soaking
                                                         (f) bleaching
                                                         (c) recovery
                                                         (e) accumu-
                                                         (g) bleaching
facilities,   (h) paper mill,   (i) cellophane paper mill,  0)  wet fiber plate
facilities,   (k) waste gas washing facilities.
                               10

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(24)  FERTILIZER MANUFACTURING
      (a) filtration facilities,    (b) separation facilities,    (c)  water jet breaking
      facilities,   (d)  waste gas washing facilities,   (e)  wet dust collector.
(25)  SODIUM  HYDROXIDE AND POTASSIUM  HYDROXIDE  MANUFAC-
      TURING (MERCURY ELECTROLYSIS)
      (a) electrolyte refining facilities,   (b)  electrolyzing facilities.
(26)  INORGANIC PIGMENT MANUFACTURING
      (a) washing facilities,    (b) filtration facilities,   (c) centrifuger (cadmium
      and its compounds),    (d)  water flushing separate (erdigris),   (e)  waste gas
      washing facilities.
(27)  INORGANIC CHEMICALS MANUFACTURING  EXCLUDING ITEMS OF
      25 AND 26
      (a) filtration facilities,     (b) centrifuger,    (c)  sulfur dioxide gas  cooling
      and washing  facilities (sulfuric acid),       (d) washing  facilities (activated
      carbon and carbonated  disulfur),    (e) hydrochloric acid regenerating facili-
      ties (silicate anhydrous),    (f)  reactor (cyanides),    (g)  absorber and sedi-
      mentation facilities (iodines),    (h) sedimentation  facilities (saline magnesia),
      (i) water flushing facilities  (bariumates),     (j) waste gas washing facilities,
      (k)  wet dust collector.
(28)  ETHYLENE DERIVATES MANUFACTURING (CARBIDE PROCESS)
      (a) wet ethylene generation facilities,    (b) washing facilities and still (ace-
      tate ester),   (c) methyl alcohol still (polyvinyl alcohol),   (d) still (acrylic
      acid ester),   (e) vinyl chloric monomer washing facilities,   (f) chloroprene
      monomer washing facilities.
(29)  COAL TAR PRODUCTS MANUFACTURING
      (a) sulwuric acid  washing facilities  of benzene relates,     (b) waste pits,
      (c) tar sodium fulfonate reactor.
(30)  FERMENTATION INDUSTRY EXCLUDING ITEMS OF 5, 10 AND  13
      (a) initial preparation facilities,      (b) still,      (c) centrifugal  decanter,
      (d) filtration facilities.
(31)  METHANE DERIVATES MANUFACTURING
      (a) still (methyl alcohol and  4-chloromethane),      (b) refining facilities
      (formaldehyde),   (c) washing and filtration facilities (fione gas).
(32)  SYNTHETIC  PLASTIC MANUFACTURING
      (a) filtration facilities,    (b) water washing facilities (pigments or dye lake),
      (c) centrifugal decanter,  (d)  waste gas washing facilities.
(33)  SYNTHETIC  PLASTIC MANUFACTURING
      (a) condensation reactor,     (b) water washing facilities,    (c) centrifugal
      decanter,    (d) settling facilities,   (e) cooling gas washer and still (florides
      plastics),    (0 diluent still (polypropylene),    (g)  diluent still (polyethy-
      lene),     (h) acid and alkali treatment facilities (polybutane),   (i)  waste gas
      washing facilities,   (k) wet dust collector.
                                      11

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(34)  SYNTHETIC RUBBER MANUFACTURING
      (a) filtration facilities,    (b) dehydration facilities,   (c)  washing facilities,
      (d) latex  concentration facilities,     (e)  sedimentation facilities (styrene-
      butadiene, nitrile-butadiene and poly butadiene-gum).
(35)  ORGANIC GUM CHEMICALS MANUFACTURING
      (a) destination facilities,    (b)  waste gas washing facilities,    (c) wet dust
      collector.
(36)  SYNTHETIC DETERGENT  MANUFACTURING'
      (a) acid washing and separating facilities,    (b)  waste gas washing facilities,
      (c) wet dust collector.
(37)  PETROCHEMICAL  INDUSTRIES (CARBOHYDRATE  AND  ITS DERI-
      VATES) EXCLUDING ITEMS FROM 31 TO 36 AND  51
      (a) washing facilities,    (b) separation  facilities,    (c) filtration facilities,
      (d) distillation and rapid  cooling facilities (acrylonitrile),    (e) distillation
      facilities (acetoaldehyde, eterphatalic acid, thylene diamine),    (f) acid and
      alkali  treatment facilities  (alkyl  benzene),    (g) distillation  facilities  and
      sulphuric  acid  concentration  facilities  (iso-propyl  alcohol), (iso-propyl
      alcohol),     (h) distillation and condensation reactor (alcohol),    (i) gas
      cooling and washing facilities (phalic acid anhydride),    (J) acid and alkali
      treatment facilities (cyclohexane),   (k) methylalcohol  distillation facilities
      and acid, alkal  treatment facilities,     (1)  steam condenser (ethylketone),
      (m) methylalcohol recovery  facilities and reactor (methy-m-acrytate mono-
      mer),   (p)  waste gas washing facilities.
(38)  SOAP MANUFACTURING
      (a) initial preparation facilities,   (b) salting out facilities.
(39)  HYDROGENATED OIL MANUFACTURING
      (a) alkali conditioning facilities,   (b) deodorization facilities.
(40)  FATTY ACIDS  MANUFACTURING
      (a) distillation facilities.
(41)  PERFUMERY MANUFACTURING
      (a) washing facilities,   (b) extraction facilities.
(42)  GELATINE AND GLUE MANUFACTURING
      (a) initial preparation facilities,    (b)  lime  soaking facilities,   (c)  washing
      facilities.
(43)  PHOTO SENSITIVE GOODS MANUFACTURING
      (a) washing facilities.
(44)  NATURAL  RESIN  MANUFACTURING
      (a) initial preparation facilities,   (b) dehydration facilities.
(45)  WOODS CHEMICAL MANUFACTURING
      (a) furfural distillation facilities.
(46)  ORGANIC CHEMICALS  MANUFACTURING EXCLUDING ITEMS FROM
      28 TO 45
      (a) water  washing facilities,     (b) filtration facilities,    (c)  concentrator
      (hyrazide),   (d) waste gas washing facilities.
                                     12

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(47)  PHARMACEUTICAL MANUFACTURING
      (a) initial preparation facilities,    (b) filtration facilities,    (c) separation
      facilities,   (d) mixing facilities,   (e) gas washing facilities.
(48)  GUNPOWDER MANUFACTURING
      (a) washing facilities.
(49)  PESTICIDES MANUFACTURING
      (a) mixing facilities.
(50)  PEAGENT MANUFACTURING
      (a) processing facilities.
(51)  OIL REFINING INDUSTRY
      (a) desalting facilities,    (b) crude petroleum distillation facilities,   (c)  de-
      sulfurization  facilities,     (d) washing facilities  (volatile oil, kerosene, or
      gasoline),  (c) lubricant washing facilities.
(52)  LEATHER MANUFACTURING
      (a) washing facilities,     (b)  line  soaking facilities,    (c) tannin, soaking
      facilities,   (d) chrome bathing facilities,   (e)  dyeing facilities.
(53)  CLASS MANUFACTURING
      (a) grinding and washing facilities,   (b) gas washing facilities.
(54)  CEMENT MANUFACTURING
      (a) centrifuger,   (b) shaper,  (c) wet conditioning facilities.
(55)  READY MIXED  CONCRETE  MANUFACTURING
      (a) batcher plant.
(56)  ORGANIC SAND BOARD MANUFACTURING
      (a) mixing facilities.
(57)  SYNTHETIC  BLACK LEAD ELECTRODE MANUFACTURING
      (a) shaping facilities.
(58)  RAW POTTERY  MATERIALS MANUFACTURING
      (a) water jet  crusher,   (b) separation facilities,    (c) acid treatment facili-
      ties,   (d)  dehydration facilities.
(59)  MACADAM QUARRING
      (a) water jet crusher,   (b) separation facilities.
(60)  SAND COLLECTION
(61)  IRON INDUSTRY
      (a) tar and gas separation facilities,    (b)  gas coiling and washing facilities,
      (c) rolling facilities,   (d)  hardening facilities,  (e) wet dust collector.
(62)  NONFERREOUS METALS MANUFACTURING
      (a) reduction basins,    (b)  electrolysis facilities,     (c) hardening facilities,
      (d) mercury refinery facilities,    (e) waste gas washing facilities,    (f) wet
      dust collector.
(63)  METRIC  GOODS MANUFACTURING AND MACHINERY  INDUSTRY
      (a) hardening  facilities,       (b) surface  treatment  facilities electrolysis),
      (c) cadmium electrode and lead  electrode  processing facilities,    (d) mer-
      cury refining facilities,   (e)  waste gas washing facilities.
                                    13

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(64)  TOWN  GAS AND COKE MANUFACTURING
      (a) coal tar and gas-liquid separation facilities,     (b) cooling and washing
      facilities including desulfurization facilities.
(64)-2 WATER CLEANING FACILITIES  (excluding  those  whose cleaning capa-
      bility is less than  10,000m3 a day) OF WATER SUPPLY FACILITIES
      (defined by the provision of  paragraph 7 of Article 3 of the Water Supply
      Law),   INDUSTRIAL  WATER  SUPPLY  FACILITIES  (defined  by  the
      provision of paragraph 6 of Article  2 of the Industrial Water Supply Busi-
      ness Law) or  PRIVATE INDUSTRIAL WATER SUPPLY FACILITIES
      (defined by the provision of paragraph  1  of Article  21  of the same Law)
      (a) depositing facilities,   (b)  filter facilities.
(65)  (a) acid and alkali treatment facilities of metal surface.
(66)  (a) electro-plating facilities.
(66)-2 LODGING SERVICE (defined by the provision of paragraph 1 of Article 2
      of the Lodging Service Law, excluding boarding house service)
      (a) cooking facilities,   (b)  bath facilities,   (c)  washing facilities.
(67)  LAUNDRY
      (a) washing facilities.
(68)  PHOTO DEVELOPING
      (a) automatically washing facilities of film.
(69)  (a) slaughterhouse.
(69)-2 CENTRAL WHOLESALE MARKET FACILITIES (concerning marine pro-
      duction defined by the provision of paragraph 3 of Article of the Wholesale
      Market  Law)
      (a) wholesale market,  (b) intermediate wholesale market.
(70)  (a) waste oil treatment facilities.
(71)  (a) automatically washing facilities of car.
(71)-2 RESEARCH, DETERMINATION, MEASUREMENT  OR PROFESSIONAL
      EDUCATION  FOR  SCIENCE  AND TECHNOLOGY (excluding  human
      science)
      (a) washing facilities,   (b)  hardening facilities.
(72)  (a) night soiLtreatment plan (more than 501 population served).
(73)  (a) sewage treatment plant.
(74)  (a) waste water treatment plant.

     The water quality standards set to prevent the discharge of sewage into the
public sewerage system are designed  to conform the water quality of the effluent to
the technical standards provided under Article 8 of the Law.  They are divided into
two  categories.  One is to designate substances to be controlled for a nationwide
uniform application under Cabinet  Order.  The other group  of standards is set by
regulations instituted  by the general manager of the public sewerage system taking
into  account the types and distribution of factories in a given area, the capacities of
the final treatment facilities in the  area and other factors. As to  the items which
could damage sewerage facilities, such as the temperatures,  hydrogen ion concen-
trations, the content of normal hexan extracts  and iodic consumption, the  general

                                    14

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manager of the  public sewerage system, as in  the past, will decide obligations for
installing pre-treatment facilities by regulations, and  the  direct penalty provisions
are not introduced from the standpoint of functional damage.
     The standards established by Cabinet Order for a nationwide uniform appli-
cation (Table 4) provide for copper, zinc and other substances which are usually dif-
ficult to treat at the final sewage treatment facilities.  These are picked from the list
of substances provided for under the Water Pollution Control  Law  as substances
dangerous to human health, such as cadmium and cyanide (health items) and those
that could adversely affect the living environment, such as copper and  zinc (living
environment items). The  control values are identical to the standards provided for
under the Water Pollution Control Law and regulations instituted thereunder.
                   Table 4 Uniform Standards Set by Cabinet Order
Substances
Cadmium and Its Compounds (Cd)
Cyanide Compounds (CN)
Organic Phosphorus Compounds
(Parathion, Methyl Parathion,
Methyl Demeton and EPN only)
Lead and Its Compounds 0?t>)
Chromium (VI) Compounds [Cr (VI) ]
Arsenic and Its Compounds (AS)
Total Mercury f-H§)
Alkyl Mercury Compounds
PCB
Phenols
Copper (Cu)
Zinc (Zn)
Dissolved Iron (Fe)
Dissolved Manganese (Mn)
Chrome (Cr)
Fluorine (F)
Permissible Limits
0.1 mg/fi
1 mg/2
1 mg/2
1 mg/e
0.5 mg/fi
0.5 mg/fi
0.005 mg/fi
Not detectable
0.003 mg/fi
5 mg/fi
3 mg/fi
5 mg/fi
10 mg/C
10 mg/fi
2 mg/fi
15 mg/fi
     As to pH, BOD and other substances that can be disposable at the final treat-
ment facilities, the general manager of the public sewerage system, as in the past, can
decide, through  the enactment of regulations, the water quality standards within the
limits  provided  for under Cabinet Order taking  into  consideration the treatment
capacity of each facility and other factors.
     Under the  Water Pollution Control Law, exceptions are provided for living
environment items, such as that factories or establishments whose average daily dis-
charge of the effluent is less than 50 m3  are  exempted from direct penalty pro-
visions relevant to the sewage standards. With  a view to coordinating relevant pro-
visions with  the Water Pollution  Control Law, the sewage exempted from appli-
cation of the Water  Pollution  Control Law  are  placed  outside controls  by the
Sewerage  Law.  But the controls  are applied to  those factories or establishments
whose average daily discharge is  less than 50 m3 when they  are also  controlled
by regulations enforced under the Water Pollution Control Law.
                                       15

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                    Table 5 Limit of Standards Allowed to be Set
                           by the Regulation
Substances
PH
BOD
ss
N-hexane Extracts
Mineral Oil
Animal and Vegetable Fats
Permissible Limits
5-9
600 mg/2
600 mg/£
5 mg/E
30 mg/C
                     With respect to sanitary sewage discharged from facili-
                   ties used for manufacturing and gas supplying business,
                   the standards can be tightened up to those at the table
                   below, if it is recognized that the total amount of sanitary
                   sewage from them is equivalent to more than one-fourth
                   of sanitary sewage to be treated at the treatment facility,
                   that it will not be  sufficiently diluted by other sanitary
                   sewage before reaching the treatment facility or that there
                   is any other justifiable reason.
Substances
pH
BOD
SS
Permissible Limits
5.7-8.7
300 mg/2
300 mg/2
     Those who have violated this direct penalty provision are liable to penal servi-
tude for less  than six months or a fine of less than ¥200,000 (in accidental cases
imprisonment for less than three months or a fine of less than ¥100,000).
     The aforementioned controls are applied only to the specified factories. But
when the sewage from non-specified factories  is inferior, the general manager of the
public sewerage  system, as in the  past, can take necessary measures to them by
regulations, including an order for the installation of pre-treatment facilities.
2.2   INTRODUCTION OF  A PRIOR CHECKING SYSTEM
     Another major point  of revision  is the establishement  of a prior checking
system in which the general manager of the public sewerage system can examine in
advance plans for the construction or renovation of specified facilities which could
discharge inferior sewage. The details are followng.
2.2.1   NOTIFICATION OF  CONSTRUCTION  OF SPECIFIED FACILITIES
     Persons who use the public sewerage system to discharge  sewage  from their
factories or establishments must  submit notifications to the general manager of the
public sewerage system,  when they  build specified facilities or take other measures
on them.
     This provision enables the general manager of public sewerage system to fully
examine in  advance  the  construction and renovation of specified facilities by
obliging the operators to submit their plans in advance to the general manager of the
public sewerage system and by ordering modifications.  Matters subject to notifica-
tion are as follows:
  a.  Name or title and  address, and name of the representative if factory  or es-
tablishment is a corporate body
                                       16

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  b. Name of factory or establishment and its location
  c. Sort of specified facilities
  d. Structure of specified facilities
  e. Method of use of specified facilities
  f. Method of treating sewage discharged from specified facilities
  g- Volume, water  quality  of sewage discharged  to public sewerage system and
other matters specified by the Ordinance of the Ministry  of Construction
2.2.2  ORDERS FOR MODIFICATION  OF  PLANS
     When a  notification for the construction of specified facilities is submitted the
general manager of the public sewerage system can  order, only within 60 days from
the date  of notification, the modification of the structure of the relevant specified
facilities  and of the sewage treatment  method, if the water quality of sewage to be
discharged to the public sewerage system is not deemed to conform to the discharge
standards.  During this period, construction work and other procedures concerning
the specified facilities are to be prohibited to be  done. In ordering the modification
of the plan, the general manager can order the abrogation of the plan, if he considers
it impossible to prevent the inflow to the sewerage  system  of the sewage unable to
meet the control standards through the modification of the plan.
     However,  even  within 60  days from the date of notification,  the  general
manager  of the  public sewerage  system can approve of  the construction and  other
measures for the specified facilities if  he considers the content of the notified plan
appropriate.
2.3   INTRODUCTION OF  IMPROVEMENT ORDER  SYSTEM
     Along with the prior  checking system allowing  orders to be  given to  modify
the notified plan for the construction of specified facilities, the general manager of
the public sewerage system can order  the operator  of specified facilities to improve
their structure, their method  of sewage treatment, etc. in order to check in advance
the inflow of inferior  sewage to the  sewerage system, when he  considers that the
relevant  facilities could discharge sewage that fails to meet the  control standards.
The improvement  order includes the improvement of the structure  of specified
facilities  and the suspension of the use of specified  facilities and of the  discharge of
sewage for a  certain period. The revision of the Sewerage Law as mentioned above
will go into force as of May 1, 1977.  But the sewage discharged from  the existing
specified  factories  will  be exempted from the direct penalty and improvement  order
provisions  for six  months  from the  date of  enforcement  of the  revised law (the
period of exemption is one year for facilities designated under Cabinet Order).
3.   PRESENT STATE OF CONTROLS ON FACTORY EFFLUENT
3.1    PRESENT STATE
3.1.1  NUMBER OF  SPECIFIED  FACTORIES
     Through the  introduction  of a prior  checking  system under  the  revised
Sewerage Law, persons who plan to construct specified  facilities will be obliged to
notify the general manager  of the public sewerage system of thier content  and  other
matters.  But even  the existing law requires  a notification to the general manager of
                                      17

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the public sewerage system from  those who will establish specified facilities or dis-
charge  sewage  in  quantities as specified (more than 50 m3 per day) or of water
quality as specified (Table 2) under Cabinet  Order.
     The numbers of specified factories (factories and  other establishments equip-
ped with specified facilities) within specific sewered areas as of March 31, 1976 are
as listed on Table 6.
     And the numbers of those who submited prior notification except those  who
established specified facilities are as listed on Table 7.

                       Table 6 Numbers of Specified Factories
Classification
Plants Generated Related
Pollution Materials Relat-
ed Health Hazard
Plants Generated Pollu-
tion Material Related to
Living Environment, Dis-
charging more than 50
m3 /day of Waste Water
Plants Generated Pollu-
tion Material Related to
Living Environment, Dis-
charging less than 50
m3 /day of Waste Water
Miscellaneous
Municipalities
Major Cities*) (10)
Ordinary Cities
Sub-total
Major Cities (10)
Ordinary Cities
Sub-total
Major Cities (10)
Ordinary Cities
Sub-total
Total for
Major Cities
Total for
Ordinary Cities
Total
Number of
Specified
Factories
4.813
1,668
6,481
1,298
1,497
2,795
22,480
18,594
41,074
28,591
21,759
50,350
Number of
Required
Pretreatment
Facilities (A)
4,469
1,143
5,612
717
877
1,594
926
3,448
4,374
6,112
5,468
11,580
Number of
Installed
Pretreatment
Facilities (B)
3,672
921
4,593
419
608
1,027
450
1,535
1,985
4,541
3,064
7,605
(B)/(A)%
82.2
80.6
81.8
58.4
69.3
64.4
48.6
44.5
45.4
74.3
56.0
65.7
*) Major Cities: Tokyo, Osaka, Sapporo, Yokohama, Kawasaki, Nagoya, Kyoto, Kobe, Kitakyushu, Fukuoka.
                          Table 7 Non-Specified Factories

Classification


Plants Generated Related Pollution
Materials Related Health Hazard

Plants Generated Pollution Material Re-
lated to Living Environment, Discharging
less than 50 m3/day of Waste Water
Plants Generated Pollution Material
Related to Living Environment, Dis-
charging less than 5 Om3 /day of Waste-
Water'

Miscellaneous


Municipalities

Major Cities*) (10)
Ordinary Cities
Sub-total
Major Cities (10)
Ordinary Cities
Sub-total
Major Cities (10)
Ordinary Cities
Sub-total
Total for
Major Cities
Total for
Ordinary Cities
Total
Number of
Required
Pretreatment
Facilities (A)
57
73
130
157
195
352
381
1,307
1,688
595
1,575
2,170
Number of
Installed
Pretreatment
Facilities (B)
35
46
81
116
115
231
289
459
748
440
620
1,060

(B)/(A)%

61.4
63.0
62.3
73.9
59.0
65.6
75.9
35.1
44.3
73.9
39.4
48.8
*) Major Cities: Tokyo, Osaka, Sapporo, Yokohama, Kawasaki, Nagoya, Kyoto, Kobe, Kitakyushu, Fukuoka.
                                         18

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     On Table 8 are the numbers of specified factories that come under the Water
Pollution Control Law.  Under the  Law the uniform sewer standards on  BOD and
other living environment-related items are applied to those specified factories whose
average daily discharge exceeds 50 m3  and health-related items are  applied to all
specified  factories. The number of specified factories subject to the uniform sewer
standards is 31,891  or 14%  of the total. The corresponding number and percentage
for those factories within specific sewer areas are  9,276  and 18%.  The ratios of
those discharging more than 50 m3  daily are about the same.  And, water used by
manufacturers during 1974 totaled  18.1  billion m3, and the  total  excluding the
amount used for raw material was 16.9 billion m3.  On the other hand, the amount
of factory effluent  flown into  the  final treatment  facilities was 0.8 billion m3 or
18% of the total.
3.1.2  TYPES  OF  SPECIFIED FACTORIES
     Table 10 shows the  types of specified factories. Many of the specified facto-
ries are small in scale.

 Table 8 Specified Facilities Designated Under the Water Pollution Control Law (in Fiscal 1974)
the Table
1 in
Cabinet
Order
1
1-2
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Kind of Business or
Na-ne of Facilities
Mining and
Pig House, Horse House, Cow
House Concerning Livestock
Farming
Meat Packing and Poultry
Processing
Sea Foods Manufacturing
Canned and Frozen
Vegetables and Fruits
Manufacturing
Miso, Soy-Sauce, Edible
Aminoacid, Glutamic Acid
Vegetable Sauces and Vinegar
Manufacturing
Wheat Flour Manufacturing
Sugar Manufacturing
Bakery and Confectionary
Rice Cake and Malt Manufac-
turing
Soft Drink Manufacturing and
Brewery
Feed Staff and Organic
Fertilizering Manufacturing
Oil and Fat Manufacturing
Yeast Manufacturing
Starch Manufactuing
Dextrose Manufacturing
Noodles Manufacturing
Number of Specified Factories
Total
©
103
33,718
2,697
9,640
2,367
3,527
45
99
1,582
696
4,728
485
334
9
309
67
4,390
Whose
Volume of
Effluents
Per Day is
More Than
50m3
62
498
816
976
479
176
13
81
97
67
556
163
107
7
234
41
91
Less
Than
50m3 /d
©
41
33,220
1,881
8,664
1,888
3,351
32
18
1,485
629
4,172
322
227
2
75
26
4,299
Sum of (2)
Which
Discharge
Waste Con-
taining Toxic
Substances
©
3
0
1
0
0





3






Number of
Factories to be
Controlled by
the Uniform
Effluent
Standard
© + ®
65
498
817
976
479
176
13
81
97
67
559
163
107
7
234
41
91
0/s©
0.2
1.7
2.7
3.1
1.5
0.7
0.0
0.3
0.3
0.2
1,8
0.5
0.3
0.0
0.7
0.1
0.3
                                     19

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Table 8 Classification of Specified Factories (in Fiscal 1974)  2/3

No. of
the fable
lin
Cabinet
Order


17
18
19
20
21

22
23
24

25

26
27
28
29

30
31

32

33

34



36


37

38
39

40
41
42

43
44
45



Kind of Business or
Name of Facilities


Bean Foods Manufacturing
Instant Coffee Manufacturing
Textile Industry
Wool Scouring and Washing
Synthetic Textile Manufac-
turing
Chemical Finishing of Woods
Pulp and Paper Manufacturing
Fertilizer Manufacturing
Sodium Hydroxide and Potas-
sium Hydroxide Manufac-
turing
Inorganic Pigment Manufac-
turing Inorganic Chemicals
Manufacturing Excluding
Items of 25 and 26
Ethylene Derivates Manufac-
turing (Carbide Process)
Coal Tar Products Manufac-
turing
Fermentation Industry Ex-
cluding Items of 5, 10
Methane Derivates Manufac-
turing
Synthetic Plastic Manufac-
turing
Synthetic Plastic Manufac-
turing
Synthetic Rubber Manufac-
turing
Organic Gum Chemicals
•Manufacturing
Synthetic Detergent Manu-
facturing
Petrochemical Industries
(Carbohydrate and Its
Derivates)
Soap Manufacturing
Hydrogenated Oil Manufac-
turing
Fatty Acids Manufacturing
Perfumery Manufacturing
Gelatine and Glue Manufac-
turing
Photo Sensitive Goods
Manufacturing
Natural Resin Manufacturing
Woods Chemical Manufac-
turing
Number of Specified Factories

Total

©
21,841
9
4,934
63
52

162
1,258
73

23

69
405
69
5

39
18

67

271

23

9

24


123

26
7

10
28
17

22
7


Whose
Volume of
Effluents
Per Day is
More Than
50m3
©
131
5
1,615
36
49

10
818
56

23

44
259
35
2

22
12

38

196

15

9

19


103

7
4

6
17
8

9
3



Less
Than
50m3/d

©
21,710
4
3,319
27
3

152
440
17



25
146
34
3

17
6

29

75

8



5


20

19
3

4
11
9

13
4


Sum of (?)
Which
Discharge
Waste Con-
aining Toxic
Substances
(D


108
4


46

1



3
19
3





1

3

















5



Number of
Factories to be
Controlled by
the Uniform
Effluent
Standard
©+j3)
=(4)
131
5
1,723
40
49

56
818
57

23

47
278
38
2

22
12

39

199

15

9

19


103

7
4

6
17
8

14
3


(%)
®/S©
0.4
0.0
5.4
0.1
0.2

0.2
2.7
0.2

0.1

0.1
0.9
0.1
0.0

0.1
0.0

0.1

0.6

0.0

0.0

0.0


0.3

0.0
0.8

0.0
0.1
0.0

0.0
0.0


                               20

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Table 8 Classification of Specified Factories (in Fiscal 1974)  3/3
No. of
the Table
lin
Cabinet
Order
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66

67
68
69
70
71

72
73
74

Kind of Business or
Name of Facilities
Organic Chemical Manufac-
turing Excluding Items From
28 to 45
Pharmaceutical Manufacturing
Gunpowder Manufacturing
Pesticides Manufacturing
Reagent Manufacturing
Oil Refining Industry
Leather Manufacturing
Glass Manufacturing
Cement Manufacturing
Ready Mixed Concrete
Manufacturing
Organic Snad Board Manufac-
turing
Synthetic Black Lead Elec-
trode
Raw Pottery Materials
Manufacturing
Macadam Quarring
Sand Collection
Iron Industry
Nonferreous Metals
Metaric Goods Manufacturing
and Machinery Industry
Town Gas and Coke
Manufacturing
Acid and Alkali Treatment
Facilities of Metal Surface
(a) Electro-Plating Facilities
(b) Hotel and Inn
Laundry
(a) Washing Facilities
Photo Developing
(a) Slaughter House
Waste Oil Treatment Facilities
(a) Automatically Washing
Facilities of Car
(b) Natural Science Institute
and Laboratory
Night Soil Treatment Plant
(More Than 501 Population
Served.)
Sewage Treatment Plant
Waste Water Treatment Plant
Total
Number of Specified Factories
Total
©
246
221
12
52
6
81
462
698
2,889
2,999
24
18
1,295
732
2,284
695
236
1,385
162
4,594
3,289
61,948
25,826
759
512
35
11,071
3,744
6,607
413
185
227,929
Whose
Volume of
Effluents
Per Day is
More Than
50m3
159
139
8
11
2
63
161
107
163
277
4
17
253
336
1,211
307
122
570
137
1,609
1,177
3,473
241
238
278
7
248
744
5,482
410
144
26,112
©
87
82
4
41
4
18
301
591
2,726
2,722
20
1
1,042
396
1,073
388
114
815
25
2,985
2,112
58,475
25,585
521
234
28
10,823
3,000
1,125
3
41
201,817
Sum of©
Which
Discharge
Waste Con-
taining Toxic
Substances
@
6
5

10
1

10
357
150
130


28


7
15
232
4
481
1,882
1
1
267
1


1,980
2

9
5,779
Number of
Specified
Factories to be
Controlled by
the Uniform
Effluent
Standard
©+©
165
144
8
21
3
63
171
464
313
407
4
17
281
336
1,211
314
137
802
141
2,090
3,059
3,474
242
550
279
7
248
2,724
5,484
410
153
31,891
(%)
@/2©
0.5
0.5
0,0
0.1
0.0
0.2
0,5
1.5
1.0
1.3
0.0
0.1
0.9
1.1
3.8
1.0
0.4
2.5
0.4
6.6
9.6
10.9
0.8
1.6
0.9
0.0
0.8
8.5
17.2
1.3
0.5
100.0
                               21

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                    Table 9 Volumes of Factory Effluent by Scale
                                                             (Unit:  1,000m' /day)
Number
of
Employee
Total
1-29
30-49
50-99
100-199
200-299
300-499
500-999
1,000 and over
Number
of
Establishment
417,876
361,075
23,270
18,330
8,464
2,643
1,905
1,385
804
Sum of
Industrial
Shipment
(billion yen)
125,702
20,755
8,245
12,620
13,378
8,737
11,466
17,070
33,431
Amount
of
Water Used
®
49,606
7,357
2,299
3,382
4,275
3,293
5,052
9,680
14,268
Water Used by Objective
For Boilers
2,819
434
183
245
228
217
250
523
739
For Mate-
612
136
106
102
98
42
62
56
10
Amount
of
Sewage
46,175
6,787
2,010
3,035
3,949
3,034
4,740
9,101
13,519
Note: Amount of Industrial Waste Water from the establishments of 1 to 29 employee is estimated.

3.1.3  INSTALLATION STATE OF  PRE-TREATMENT  FACILITIES
     The Sewerage  Law before revision provided that  the general manager of the
public  sewerage system, through the enactment of regulations, establish standards
for the installation of pre-treatment facilities in accordance with the standards set by
Cabinet  Order.   Therefore,  the  standards  applied  for the  construction of pre-
treatment facilities  vary with  cities, towns and villages. The number of establish-
ments that are required to install pre-treatment  facilities is 13,750. The number of
those already equipped with such facilities is 8,665 or 63% of the total. The ratio of
the factories which have already had pre-treatment facilities is higher among those
having the facilities such as electroplating discharging harmful substance.
3.1.4  SURVEILLANCE ON FACTORY EFFLUENT
     The general  managers  of the public sewerage system can order his staff to enter
land or buildings  owned by others and inspect sewage systems, pre-treatment facili-
ties and  other objects for the purpose of maintaining the structure and functions of
the public  sewerage system and conforming the water quality of the effluent to the
technical standards provided  for under Article  8 of the  Law.  The number of in-
spections conducted in fiscal 1975 totaled approximately 27,000.
     For proper management of the public sewerage system, its general manager can
also collect from the operator  of the specified facilities reports on the state of
factories discharging  sewage  and pre-treatment facilities  as  well as on the water
quality of the sewage  discharged by these facilities. The number of reports collected
during fiscal 1975 totaled about 6,700.
     The administrative actions taken by the general manager of the public sewerage
system during fiscal 1975 under the Sewerage Law are as follow:
     Order for Improvement:                   67 cases
     Recommendation for Improvement:     271 cases
     Warning:                                46 cases
     Total:                                384 cases
The figure represents an increase of 328 cases over fiscal 1974.  This is a result of
strengthened surveillance by the general manager of the public sewerage system just
                                      22

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Table 10 Types of Specif led Factories
No. of the
Table 1 in
Cabinet
Order
1
1-2
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
Kind of Business or
Name of Facilities
Mining and Coal Washing
Pig House, Horse House, Cow House
Concerning Livestock Farming
Meat Packing and Poultry Processing
Sea Foods Manufacturing
Canned and Frozen Vegetables and
Fruits Manufacturing
Miso, Soy-Sauce, Edible Aminoacid,
Glutamic Acid Vegetable Sauces and
Vinegar Manufacturing
Wheat Flour Manufacturing
Sugar Manufacturing
Bakery and Confectionary
Rice Cake and Malt Manufacturing
Soft Drink Manufacturing and Brewery
Feed Staff and Organic Fertilizering
Manufacturing
Oil and Fat Manufacturing
Yeast Manufacturing
Starch Manufacturing
Dextrose Manufacturing
Noodles Manufacturing
Bean Foods Manufacturing
Instant Coffee Manufacturing
Textile Industry
Wool Scouring and Washing
Synthetic Textile Manufacturing
Chemical Finishing of Woods
Pulp and Paper Manufacturing
Fertilizer Manufacturing
Sodium Hydroxide and Potassium
Hydroxide Manufacturing
Inorganic Pigment Manufacturing
Inorganic Chemicals
Manufacturing Excluding Items of 25
and 26
Ethylene Derivates Manufacturing
(Carbide Process)
Coal Tar Products Manufacturing
Fermentation Industry Excluding Items
of 5, 10
Methane Derivates Manufacturing
Synthetic Plastic Manufacturing
Synthetic Plastic Manufacturing
Synthetic Rubber Manufacturing
Organic Gum Chemicals Manufacturing
Synthetic Detergent Manufacturing
Petrochemical Industries (Carbohydrate
and Its Derivates)
Soap Manufacturing
Number of
Specified
Factories
3
36
278
822
587
319
67
35
1,016
246
506
30
57
3
26
13
1,196
3,425
2
5,070
78
1
6
55
3
2
25
83
6
2
9
6
113
37
9
4
28
12
34
Number of
Required
Pretreat-
ment Faci-
lities (A)
3
9
106
233
99
98
30
8
276
45
187
23
45
1
10
10
120
292
1
558
62
1
2
42
2
2
23
75
3
2
5
3
42
28
5
3
13
9
19
Number of
Installed
Pretreat-
ment Faci-
lities (B)
2
5
53
113
44
35
7
4
76
17
105
12
19
1
6
9
29
78
1
191
12
1
0
32
1
2
19
67
3
2
4
3
37
16
5
3
8
7
17
(B)/(A) %
67
56
50
48
44
36
23
50
28
36
56
52
42
100
60
90
24
27
100
34
19
100
0
76
50
100
83
89
100
100
80
100
88
57
100
100
62
78
89
                   23

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Table 10  (Continued)
*Jo. of the
Table 1 in
Cabinet
Order
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66

67
68
69
70
71

72
73
74
Kind of Business or
Name of Facilities
Hydrogenated Oil Manufacturing
Fatty Acids Manufacturing
Perfumery Manufacturing
Gelatine and Glue Manufacturing
Photo Sensitive Goods Manufacturing
Natural Resin Manufacturing
Woods Chemical Manufacturing
Organic Chemical Manufacturing Exclud-
ing Items From 28 to 45
Pharmaceutical Manufacturing
Gunpowder Manufacturing
Pesticides Manufacturing
Reagent Manufacturing
Oil Refining Industry
Leather Manufacturing
Glass Manufacturing
Cement Manufacturing
Ready Mixed Concrete Manufacturing
Organic Snad Board Manufacturing
Synthetic Black Lead Electrode
Raw Pottery Materials Manufacturing
Macadam Quarring
Sand Collection
Iron Industry
Nonferreous Metals
Metaric Goods Manufacturing and
Machinery Industry
Town Gas and Coke Manufacturing
Acid and Alkali Treatment Facilities of
Metal Surface
(a) Electro-Plating Facilities
(b) Hotel and Inn
Laundry
(a) Washing Facilities
Photo Developing
(a) Slaughter House
Waste Oil Treatment Facilities
(a) Automatically Washing Facilities of
Car
(b) Natural Science Institute and Labor
Laboratory
Night Soil Treatment Plant (More Than
501 Population Served.)
Sewage Treatment Plant
Waste Water Treatment Plant
Number of
Specified
Factories
4
9
10
3
29
2
4
105
88
4
6
5
24
211
71
67
88
4
5
14
8
7
267
76
822
24
2,409
2,327
11,623
8,273
1,162
31
94
2,650
565
55
-
15
Number of
Required
Pretreat-
ment Faci-
lities
4
8
8
3
25
2
1
83
62
3
5
5
19
197
51
33
49
3
2
12
2
3
113
65
283
19
2,092
2,295
634
666
834
30
77
1,304
232
20
-
12
lumber of
Installed
Pretreat-
ment Faci-
lities
4
7
7
1
20
2
1
73
51
1
5
5
19
18
38
23
41
3
2
10
1
2
89
54
197
15
2,006
1,964
269
119
559
21
70
1,031
116
19
-
7
(B)/(A) %
100
88
88
33
80
100
100
88
82
33
100
100
100
9
75
70
84
100
100
83
50
67
79
83
70
79
96
86
42
18
67
70
91
79
50
95

58
        24

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as in the case of the inspection  of water quality under the Sewerage Law which
sharply increased from about 12,000 cases in fiscal 1974 to about 17,000 cases in
fiscal 1975.
     Thus, guidance and surveillance on pre-treatment facilities in  cities, towns and
villages are being strengthened in  recent years with particular emphasis on those in
cities.  The number of officials engaged  in these works in city, town and village
offices totaled 733 during fiscal 1976.

                 Table 11 Surveillance on Pre-treatment Facilities (1975)
Classification
Reporting Commencement of
Utilization (Accumulation)
Inspection of Private Sewer
Collection of Reports
Order for Improvement
Municipalities
Major Cities (10)
Others
Total
Major Cities (10)
Others
Total
Major Cities (10)
Others
Total
Major Cities (10)
Others
Total
Number
12,107
13,532
25,639
14,077
12,902
26,979
2,855
3,889
6,744
135
249
384
                Major Cities: Tokyo, Osaka, Sapporo, Yokohama, Kawasaki,
                         Nagoya, Kyoto, Kobe, Kitakyushu, Fukuoka.
3.2   AID SYSTEM  FOR CONSTRUCTION OF PRE-TREATMENT FACILITIES
     Under the Sewerage Law before revision, factories and other establishments
were already obliged to equip themselves with pre-treatment facilities. As a result of
the introduction of the prior checking system and the direct penalty system under
the revised law, the construction  of the pre-treatment  facilities has become indis-
pensable.  The  standards for the construction of the pre-treatment facilities are not
uniform, since they are decided  by regulations instituted  respectively by cities,
towns  and villages. The factories which have not installed the pre-treatment facili-
ties total 5,085 in number and represent 37% of those which are required  such
facilities.  Among  reasons for delayed action are lack of funds, lack of land, under
planning and under construction as listed on Table 12. Many of the factories which
have not yet built the pre-treatment facilities are small businesses, and therefore the
state and local governments have established aid systems to promote the construc-
tion of the facilities as listed on Table 13.
3.3   PUBLICATION  OF  GUIDANCE MANUAL
    Under the revised Sewerage Law,  cities, towns and villages serving as general
manager of the public sewerage system are obliged to  assume clerical  works  con-
cerning the prior  checking system and other procedures.  This means  that cities,
towns  and villages will  handle  the  same clerical  works as  those  assumed by the
prefectural governments  (partly delegated to major cities)  provided for under the
                                      25

-------
Water  Pollution  Control Law, including the prior checking system. In order  to
help smaller administrative bodies carry out  the newly-assigned work smoothly,
the state has decided to publish a guiding manual for the prior checking system
and  other procedures, and the Sewerage Association is now studying  the plan.
     The state has  also  instruct the local governments to  prepare new registers
for the pre-treatment facilities in a unified form with a view to strengthening surveil-
lance on specified establishments and giving proper guidance.

                         Table 12 Reasons for Non-Installing
                                 Pre-treatment Facilities

Lack of Money
Lack of Space
Planning to Install
Tentative Treat-
ment
Planning to Move
Others
Total
Specified
Factories
(%)
34.3
17.8
15.0
11.1
0.8
21.0
100.0
Non-specified
Factories
(%)
24.3
0.9
5.7
26.3
0.1
42.7
100.0
              Table 13.1 Aid System of Financial Institution for Installing
                       Pre-treatment Facilities (March 1976)
Corporation
Environmental Pollution
Control Service Cor-
poration







-





Japan Development
Bank
/A recommendation of\
f the authority con-
A cerned is necessary to ,
Smaller Business
Finance Corporation



People's Finance
Corporation




Smaller Business Pro-
motion Corporation


Object Enterprise
Big Enterprise

Small-to-Middle Enter-
prise
/Capital Stock; less than\
[ 100 million yen ]
\ Employee; less than J
\> 300










Enterprises Except Object
Enterprises of the Loan of
the Smaller Business
Finance Corporation

Small-to-Middle Enter-
prise
/Capital Stock; less thanv
/ 100 million yen \
\ Employee; less than /
\ 300 '


Mainly Smaller-to-Middle
Enterprise
.Capital Stock; less than.
/ 10 million yen \
\ Employee; less than /
\ 100 '
Cooperative Anti-Pollu-
tion Business of Business
Cooperative Association
etc.
Maximum
Sum of
Loan
Non-limit















Non-limit



Direct
Loan:
150
million yen
Loan by
Agent
40 mil-
lion yen
18 mil-
lion yen




Non-limit



Interest Rate
(per year)
Big Enterprise

Cooperative Anti-Pollu-
tion Facilities
First 3 years; 7.5%
' Later; 7.7%
Individual Anti-Pollu-
tion Facilities; 7.7%


Smalt-to-Middle Enter-
prise
Cooperative Anti-Pollu-
tion Facilities
First 3 years; 4.5%
Later; 5.0%
Individual Anti-Pollu-
tion Facilities; 6.0%
First 3 years; 7.7%
Later; 8.2%


First 3 years; 7.0%
Later; 7.2%



First 3 years; 7%
Later; 7.2%




Non-interest



Term of Redemption
Cooperative Anti-Pollu-
tion Facilities
{Instrument and Equip-
ment; 10 years
(unredeemed 1 year)
Others; 20 years
(unredeemed 3 years)
Individual Anti-Pollution
Facilities; 10 years
(unredeemed 1 year)








About 10 years



10 years
(unredeemed 2 years)



10 years
(unredeemed 2 years)




15 years
(unredeemed 2 years)


Amount of Loan
(1976F.Y.)
Cooperative Anti-Pollu-
tion Facilities, Indi-
vidual Anti-Pollution
Facilities. Others;
127 billion yen













Pollution Prevention
Facilities, Anti-Pollu-
tion Facilities, Others;
128 billion yen

Safety Loan, Anti-Pollu-
tion Loan; 53 billion
yen


Safety Loan, Anti-Pollu-
tion Loan; 10 billion
yen



2 billion yen



                                       26

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       Table 13.2 Aid System of Major 7 Cities for Installing Pre-treatment Facilities
City
Tokyo Metropolis
/All 23 ward have the v
/ system to supply \
\ money for interest J
Bother than these. '
Yokohama
Nagoya
Kyoto
Osaka
Kobe
Kitakyushu City
Name of System
Tokyo Metropolis Media-
tion System for Loaning
of Anti-Pollution I und
Tokyo Metropolis Loan-
ing System for Anti-
Pollution Fund
Yokohama Cily Loaning
System for Small-lo-
Middle Enterprise
(Anti-Pollution fund)
Nagoya Cily Mediation
System for Loaning of
Anti-Pollution Facilities
Improvement Fund
Kyoto City Anti-Pollu-
tion Fund System
Osaka City Loaning
System for Anti-Pollu-
tion Facilities
Kobe City General Loan-
ing System of Anti-
Pollution Fund
Kitakyushu City Loaning
System of Anti-Pollu-
tion Fund
Maximum
Sum of Loan
20 million yen
7 million yen
25 million yen
25 million yen
20 million yen
20 million yen
20 million yen
10 million yen
Interest Rate
Metropolis Supplies
Money for Interest so that
Interest Rate may be 2
percentage.
29f
Cily Supplies All Money
for Interest.
6.8ft
\.S7r
City Supplies Money for
Interest so that Interest
Rate may be 2 percentage
(1 percentage for small
enterprises)
Cily Supplies Money for
Interest so that Interest
Rate may be 2.76 per-
centage.
City Supplies All Money
for Interest.
Term of Redemption
7 years
(unredeemed 6 months)
7 years
(unredeemed 6 months)
3 to 9 years
7 years
(unredeemed 1 year)
12 years
7 years
7 years
7 years
Amount of Loan
(1976F.Y.)
5 billion yen
{including fund for
movement)
300 million yen
600 million yen
2 billion yen
660 million yen
(including fund for
movement)
150 million yen
650 million yen
300 million yen
                     Table 13.3 Utilization State of Aid System for
                               Installing Pre-treatment Facilities
                               (1971-1975 F.Y.)
Classification


National
Government



Local
Government
System
Environmental Pollution
Control Service Corpora-
tion
People's Finance
Corporation
Smaller Business Finance
Corporation
Smaller Business
Facility Modernization
Fund
Environmental Sanitation
Business Finance
Corporation
Sub-total
Prefecture
Municipality
Sub-total
Total
Number
45
327
56
14
1
443
117
834
951
1,391
     Mentioned  above  are  a summary of  the  revision of the Sewerage Law, the
state  of controls on factory effluent before the revision and the  new system of
surveillance under the revised law. A report on  the state of the execution of the
revised law will be made on the next occasion.
                                        27

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           RECENT TOPICS IN WATER POLLUTION CONTROL
                              IN JAPAN
1.   Current Progress on Water Pollution Control in Japan	29
2.   Surveys for Total Emission Control for Organic Pollutants  	32
3.   Counter Measures for Eutrophication	33
4.   Other Water Pollution Phenomena	34
  4.1    Effluent Discharged in Warm Temperature	34
  4.2    Long Time Duration of Turbid Water Flow from Dams	34
5.   Environment Impact Assessment	35
                                   28

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           RECENT TOPICS IN WATER  POLLUTION CONTROL
                                IN JAPAN
1.   CURRENT PROGRESS ON WATER POLLUTION CONTROL IN JAPAN
    The state of this country's water pollution caused by cadmium and other toxic
substances has improved lately with the years. In terms of BOD (or COD in the case
of lakes and sea water), the principal index of water quality with regard to organic
substances, water  pollution  in major water  bodies has definitely slowed — even
improved in certain areas —  since  1969, thanks to the rigorous regulation of efflu-
ents throughout the country in recent years. However, there still remain  areas where
water pollution  is not in good condition, and they include the river waters that run
through cities where the population and industries are heavily concentrated and the
coastal waters,  particularly  those of bays and inland seas where  the waters are
trapped within a certain area.  In the following pages, we will raise some questions to
be discussed at the 5th US/JAPAN conference on sewage treatment technology.
                                    29

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              Table 1 Degree of Nonconformity with Toxic Substance

                      Environmental Standards
Substance


Cadmium




Cyanides



Organic
Phosphorus




Lead




Hexavalent
Chrome


Fiscal Year
1970
71
72
73
74
75
70
71
72
73
74
75
70
71
72
73
74
75
70
71
72
73
74
75
70
71
72
73
74
75
Percentage
2.8 %
0.7
0.34
0.32
0.37
0.31
1.5
1.2
0.5
0.2
0.06
0.02
0.2
0.2
0
0
0
0
2.7
1.4
0.7
0.65
0.37
0.32
0.8
0.1
0.07
0.08
0.03
0.02
Substance


Arsenic




Total Mercury



Alkyl Mercury




Total


Fiscal Year
1970
71
72
73
74
75
70
71
72
73
74
75
70
71
72
73
74
75
70
71
72
73
74
75
Percentage
1.0 %
0.4
0.29
0.31
0.27
0.24
1.0
0.3
0.04
0.01
] See Notes*
0
0
0
0
.0
0
1.4
0.6
0.3
0.23
°-20U*
0.17J






T * i »i      c-  i  >~!A   j >T<-
Total Mercury Fiscal  74 and 75
Except Total Mercury
                               Numbers of Stations Exceeding Standards   „„
                              - - — — — - - — — - - = 0%
                                      Total Number of Stations
                                       30

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Table 2 Degree of Nonconformity with Standards Relating
       to the Living Environment
                                        (FY'75,(  ) shows FY'74)
Body of Water Category



Rivers





Lakes and Marshes



Sea Areas

AA
A
B
C
D
E
Total
AA
A
B
C
Total
A
B
C
Total
Numbers of Samples
Not Meeting Standards ea^
Total Numbers of Samples ^'"'
22.2
22.6
21.3
17.4
12.5
24.1
21.3
32.5
39.1
46.2
30.3
38.4
18.1
14.2
8.4
16.1
(24.2)
(23.0)
(23.3)
(18.7)
(13.4)
(27.1)
(22.4)
(33.4)
(34.7)
(48.1)
(25.3)
(35.1)
(18.8)
(14.0)
( 7.1)
(16.0)
                         31

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2.   SURVEYS  FOR TOTAL EMISSION CONTROL  FOR ORGANIC
     POLLUTANTS
     The regulation  introduced under the Water Pollution Control Law has only
taken into account the concentration of pollutants, but it seems insufficient that to
meet the demand for some specific water areas such as lakes and bays.
     Therefore, surveys for introduction of so-called "total emission control," i.e.,
limitation of the emission of certain pollutants at each  individual source so that the
total emission volume for a given water area is less than a level to meet the environ-
mental standards of the water area concerned.
     The item for total emission control in water pollution control is intended to be
COD, one of the  items  relating to living environment, while the items for total
emission control  in air pollution control are the items relating to human health.
     In  May 1975, Water Quality Bureau established a study committee for total
emission control (headed by Professor Ishibashi of Tokyo University). Since then,
the committee has studied  fundamental structures of  total emission control, i.e.,
pollutants or items to be  controlled, water areas to be controlled (that means to be
designated),  the method of calculation of total emission volume, allocation method
of total emission volume for each individual source, and the method of supervision
and measurement.  The committee,  after five times  sessions, on September 1975,
issued an interim report consists of three parts (I. Fundamental plan, II. Way of
regulation, III. Supervision and measurement).
     According to this, a  fundamental survey is now  carrying on as to Tokyo Bay,
Ise Bay  and  Seto Inland Sea for the  introduction of total emission control of pollu-
tants, FY 1976.  Also, in FY 1977, similar survey is intended as to Lake Biwa, Lake
Suwa and Lake Kasumi.
                                     32

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3.   COUNTER MEASURES FOR EUTROPHICATION




     Among the recent features of water pollution, eutrophication problems in the




specific water areas, such as Seto Inland Sea, Tokyo Bay and Lake Kasumi, are most



troublesome.




     As to "red tides" in the Seto Inland Sea, although the incidence of formation




has been increasing annually, the percentage of cases where damage has been suffer-




ed has been decreasing (Table 3).  Part of the increased occurrence is actually due to




more comprehensive surveillance and reporting and not to more frequent red tide




formation, but even taking this factor into account, the virtually irreversible process




of eutrophication is still clearly being accelerated in those areas where nutrient salts




using microorganisms as their medium are building up in the water.  The result is the




abnormal phenomenon  of red tide formation and  other types of secondary organic




pollution.





                     Table 3 Change in the Incidence of Red Tides
^"^--^^^^ Year
Item "~~" — ~^^
No. of Time (A)
No. of Times with Fish-
ery Damage (B)
(B) nn ,~,
(A) x 100 (96)
1967
48
8
17
1968
61
12
20
1969
67
18
27
1970
79
35
44
1971
136
39
29
1972
164
23
14
1973
210
18
9
1974
298
17
6
                                                         Source: Fishery Agency






     Hence, from  FY  1972, surveys  of phosphorus and nitrogen are carried out




about major sea areas  and lakes.  From FY  1975, in Seto Inland Sea and Ise Bay,




and in FY 1977, adding Tokyo Bay, surveys for phosphorus and nitrogen are carried




out,  as to input charge of each individual source, dissolving from bottom sediment,




plankton and so on.




     As to synthetic detergent, JIS (Japan Industrial Standard) relating to synthetic

-------
detergent for clothes is  amended  in December 1976, and phosphate  content is




reduced from 8 to 20% to less than  12%.






4.   OTHER WATER POLLUTION PHENOMENA




4.1  EFFLUENT DISCHARGED  IN  WARM TEMPERATURE




     Recently,  power stations are becoming much larger and also they are apt to be




constructed in  the areas where there have been no water pollution problems before.




So it is worried about that the effluent discharged from those power stations in state




of warm temperature affect badly to marine life and fishery.




     In December 1975, "Thermal Pollution Committee" of Water Quality Commit-




tee of The Central Council for Control of Environmental Pollution issued an interim




report as to  thermal pollution. It says that, the necessity of continuing surveys, and




sufficient environmental  impact assessment  when a new power station is planned,




and  also  the necessity of monitoring of environment after the completion of con-




struction.






4.2  LONG  TIME DURATION OF TURBID  WATER  FLOW  FROM DAMS




     One of the problems recently  raised is the long time duration of turbid water




flow down from dams after rainfall. Generally speaking, Japanese rivers are usually




clear in turbid  because of geological and geographical conditions, and when it rains




the turbidity of river  flow will go up promptly and when it clear up the turbidity of




river flow go down again promptly.  But, if a dam is constructed it is usual there




comes a long time duration of comparably high turbid water after rain is up. And




this gives a  bad  effect to utilization of river  water and  fishery.  And  also is the




problem that a  dam brings a cold water according to the way of discharge.
                                    34

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5.   ENVIRONMENT IMPACT ASSESSMENT



     When  various development  works in relation to any public water areas are



carried out, it is necessary to take proper preventive measures so that such works



may not adversely affect the environment. For this purpose, it is very important to



make environmental impact assessment,  thereby to make  a careful check  of the



possible effects such development works may have on  the adjacent environment.



     The above-mentioned basic policy was approved at the  Cabinet meeting held in



June 1972  and was  adopted as a  government policy.  Thereafter, the environmental



impact assessment has been carried on in accordance  with this policy.  This concept



of environmental impact  assessment was embodied in various laws enacted at 71st



session of  the National Diet during 1973.  The  provision  in the  Seto Inland-Sea



Conservation Law is a good example. This law stipulates  that  an application for



permission  for building specific industrial facilities in the coastal areas of the Seto



Inland-Sea shall be accomplished with the statement of the results of the preliminary



evaluation made by  the surveys on possible influences the proposed industrial facili-



ties may  have on the surrounding environments. The law  also  stipulates that the



said  document should be made available to public inspection for a period of three



weeks.



     The  general procedures for environmental impact assessment is shown in Fig. 1.
                                     35

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                  Fig. 1 Procedures for Environmental Impact Assessment
 Measures for
Environmental
 Preservation
                 Development Project (alteration of
                 nature, housing, transportation, produc-
                 tion activities, etc.)
                             Formulation
                           of List of Survey
                                Items
                           Determination of
                             Survey Items
                         State of Survey Items
  Environmenta
Load Forecasting
     Model
Forecasted Environ-
mental Load Volume
i
r
                            Environmental
                          Change Forecasting
                                 Model
Forecasted Environ-
mental Change
i

                                                             Environmental
                                                               Standards
                                                                  Human Health
                                                                     Nature
                                                                  Conservation
                                                                   Preservation
                                                                    of Living
                                                                   Environment
                                        36

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                      FIFTH US/JAPAN CONFERENCE
                                 ON
                     SEWAGE TREATMENT TECHNOLOGY
                            PAPER NO, 2
STUDIES ON STORN AND COMBINED SEWER
             OVERFLOW
         APRIL 26-28,  1977
           TOKYO,  JAPAN
      MINISTRY OF CONSTRUCTION
        JAPANESE GOVERNMENT

                37

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     STUDIES  ON STORM AND  COMBINED  SEWER  OVERFLOW
1.  WATER QUALITY CHARACTERISTICS  OF STORM &  COMBINED
   SEWER OVERFLOW	39
      K. Takeishi, Ministry of Construction
2.  COMBINED SEWER OVERFLOW  SIMULATION
   -CASE  STUDY ON YABATA  SEWER CATCHMENT AREA,
   TOKYO-  	69
      T. Yamaguchi, PWRI, Ministry of Construction
                              38

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     CHAPTER 1.   WATER QUALITY  CHARACTERISTICS OF STORM
                   & COMBINED SEWER OVERFLOW
1.1   Current Status of the Combined Sewer System in Japan	40
  1.1.1  Combined Sewer System  	40
  1.1.2  On-going Measures and Research Activities for the Combined
        Sewer Systems	40
1.2   Examples of Measures against Combined Sewer Overflow Problems	42
  1.2.1  Storm Water Sedimentation Tank in Osaka    	    42
  1.2.2  Storm Water Detention Trunk Sewer in Osaka	42
  1.2.3  Storm Water Sedimentation Tank in Yokohama	42
1.3   Interim Results of Basic Surveys by the Research Committee on
     Combined Sewer System Problems	43
  1.3.1  Method of Survey	43
  1.3.2  Outline of Survey Areas	43
  1.3.3  Survey Results    	       	45
1.4   Postscript     .       	68
                                   39

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1.   WATER QUALITY CHARACTERISTICS OF STORM & COMBINED
    SEWER OVERFLOW
1.1   CURRENT STATUS  OF THE COMBINED SEWER SYSTEM IN JAPAN
1 1.1   COMBINED SEWER SYSTEM
    In Japan as of 1975, 583 municipalities had been practicing the sewage works.
In 1976, 65 new municipalities are expected to enter upon sewage works.
    The population served by sewers in 1975 is estimated to have been 22.8% of
the total population.
    In Japan  those cities which have a long experience in the sewage works have
 the combined sewer system. According to a 1972 survey conducted by the Ministry
 of Construction, the combined sewer system accounted for 73% of the total sewered
 area,  covering 69% of the total sewered population.
     As the problems of the combined sewer overflow come to the fore, the number
 of cities adopting the separate sewer systems is on a steady rise in recent years.
     The Ministry of Construction is also a strong promotor of the separate sewer
 systems.  Table 1.1 shows  the changes  in the past three years of the number of
 municipalities by type of sewerage.
     The many municipalities which have combined sewer system adopt the separate
 sewer system in new sewered areas, so  the share of the combined sewer system is
 decreasing  gradually. Nevertheless, the significance of the combined sewer overflow
 on the contribution of pollution loads in waters has not yet been reduced at all. In
 large cities where  the sewerage is making a large step toward improvement through
 secondary  treatment, the contribution for water pollution by combined sewer over-
 flow  will be increased more and more.

            Table 1.1 Relative Use of Combined Sewers of Local Governments
^~\_ Year
-\^^
Sewer systerrT^^^^
Combined sewer
Hybrid
Separate sewer
Total

1973

70
158
217
445

1974

52
176
287
515

1975

47
185
351
583
 1.1.2   ON-GOING MEASURES AND RESEARCH ACTIVITIES FOR THE
        COMBINED SEWER  SYSTEMS
 1.1.2.1  MEASURES  FOR THE COMBINED SEWER SYSTEM
      In Japan, little has been reported of examples taking radical measures against
                                     40

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pollution caused by  combined sewer overflow.  Most of municipalities have been
bending their efforts for the expansion of sewer-served areas.  Although they have
full knowledges on the problems the combined sewer system has, their efforts don't
reach to the measures against them.
     In the major cities where the sewerage system has long been used, improvement
of overflow chamber and  enlargement  of sewer capacity are being pushed for-
ward  in order to recoup shortage of the capacity of the existing sewer  system and
to overcome the problem of reduced dilution ratio of wet-weather overflow. These
improvements, however, are still in the stage of local scale practice, and come  no-
where near providing a meaningful  way against the water pollution by wet-weather
overflow.
     What is standing in the way of changing the combined system to the separate
system lies in  the vast sums of money required, narrow width of road in densely
populated area, and  the fact  that storm water from storm sewer itself  is polluted.
Converting to the separate system is not considered to be the best solution.
     Most of measures taken or being planned to control the water pollution by
combined sewer overflow are either detention or sedimentation of wet-weather over-
flow.
    A facility installed in Osaka is the only one example of this type now we can
see in Japan, except for two additional facilities which are now under construction.
     All these three are touched upon briefly in the next section. Some new districts
which adopted combined sewer systems install storm water sedimentation basins in
their  sewage treatment plants in order  to  overcome the  problems of wet-weather
overflow.
1.1.2.2   Current Research Activities
     For the purpose of studying the improvement measures for the combined sewer
system, the  Ministry of Construction  established an research  organization  named
"Research Committee on Sewer System Problems." The members of the  Committee
consist of the engineers from the Ministry of Construction, the Japan Sewage Works
Agency, major municipalities and representative medium-sized municipalities.  Of
these  municipalities, eleven adopt the combined sewer system, and one the separate
sewer system.
    The principal objective of this Committee is to investigate about the combined
sewer system in each municipality by standardized manners, exchange findings and
formulate practical improvement measures.
    The Committee  is scheduled to work from 1975  to 1980.  For the first three
years, the Committee will bend their energies to collect data with emphasis  on  the
fact-finding survey.
    The data obtained this way  is significant not only for the improvement of the
combined sewer system, but also as a basis for the planning of future sewer system.
     Section 3  summarizes the findings acquired by the Committee in 1975.
    The Urban River Section of the Public Works Institute, Ministry of Construc-
tion,  developed a water quality simulation model of the  combined sewer system.
The mode which stands on the concept of the retention of pollution load gives the
pollutegraph from a given hydrograph.

                                     41

-------
    It is corroborated by application of this model to some drainage areas that the
simulated results agree well with actual measurements.  The model is considered to
become a useful tool in assessing  the improvement of combined  sewer system
because it can  estimate the pollutegraph from  the hydrograph calculated by the
modified RRL method from the precipitation record.
    The results of this study are discussed in the next chapter.
1.2   EXAMPLES OF MEASURES AGAINST COMBINED SEWER OVERFLOW
      PROBLEMS
    In  Japan, there  are not so many practical examples of measures to control
water pollution due to combined sewer overflow.
    Briefed here are three examples in Osaka and Yokohama.
1.2.1   STORM WATER SEDIMENTATION TANK IN OSAKA
    In 1975, the Osaka Municipal Government constructed storm water sedimenta-
tion tank consisting of two basins by taking advantage of the improvement work of
Nakanoshima Pumping  Station  at the center of the city.  The  dimension of each
basin  is 3.5 m in width, 20.2 m in length and 4.5 m to 5.0 m in depth. In the future,
four additional basins will be constructed.  When all these tanks are completed, the
storage capacity will  become 2,000 m3 or worth 4.4 mm of rainfalls  in  the area.
This facility is the only one example in Japan of measures against wet-weather over-
flow.
1.2.2   STORM WATER DETENTION TRUNK SEWER  IN  OSAKA
    In Osaka, innundation frequently visits lowlands because of  marginal use of
catch basin and subsidence due to excessive use of ground water.   In  order to
solve  this problem, installation of a new interceptor was planned and has been under
way since 1973.
    Its major portion having an inside diameter of 6,000 mm will be installed 25 m
deep  with the length of about  3 km, and will provide a storage capacity of some
80,000 m3 or worth 6.6 mm of rainfalls in the area.
    This trunk sewer is planned to  serve for the control of water  pollution due to
wet-weather  overflow without  detriment to the original purpose of innundation
control.
 1.2.3   STORM  WATER SEDIMENTATION TANK IN YOKOHAMA
     The  Yokohama  Municipal  Government  is in the process  of  constructing
 storm water sedimentation tank consisting of eighteen 6.0 m wide by 35 m long by
 6.0 m deep basins with a total  capacity of 22,680 m3 equivalent to 6.4 mm of rain-
 falls in the area.
     The tanks  are of the underground type, and their covered top is planned to be
an  athletic ground open to the public. These tanks are expected to reduce the pollu-
tion loads by 10% or more in SS and almost the same degree in BOD  as compared
with the separation device.
                                    42

-------
1.3   INTERIM RESULTS OF BASIC SURVEYS  BY THE  RESEACH
      COMMITTEE ON COMBINED SEWER SYSTEM PROBLEMS
1.3.1   METHOD OF  SURVEY
    For the purpose of collecting extensive data on the characteristics of wet-
weather combined sewage, twelve drainage areas different in drainage system and
land use were selected as the study areas in the eleven member municipalities. The
designated areas have already been perfectly covered by the combined sewer system,
have a sizable tract each, and also are favoured with conditions permitting hydraulic
and hydrologic analysis with ease.
    In one city which has adopted  the separate sewer system,  a survey area
was also sited  to fulfil  similar conditions.  A survey station was installed at the
downmost end  of the sewer in each survey area for flow measurement and sampling.
At several spots in the survey area, rainfall gaging was also carried out. The sampled
water  was  subjected  to analysis  according to analysis according to the unified
methods.
    In 1975, flow measurement and sampling were conducted one to two times in
dry-weather  and two to four times  in wet-weather in the combined sewer survey
areas  and four  times  in wet-weather  in the  separate  sewer  survey  area.  In the
separate  sewer  municipality,  the  survey area was relocated  in 1976 to a suburb
where three-times surveys were carried out in wet-weather.
     In addition, geographical and social conditions, including land use patterns and
demographic status, were also investigated in each survey area.
1.3.2   OUTLINE OF SURVEY AREAS
    The combined sewer survey areas are outlined in Table 1.2 (a), and the separate
sewer survey areas in Table 1.2 (b).
    The following is a list of survey areas and a brief explanation of each.

Combined sewer survey areas
A:   Single-family residential area apart from the city center
B:   Populated urban area with a mixed consist of residential houses and stores
C:   Area with a mixed  consist of small to medium factories,  residential houses and
  stores
D:   Area with residential zones and shopping quarters
E:   Residential area on  a terrace bordering on an unban area
F:   Area with low-story and medium-story  shopping  quarters and amusement
   quarters
G:  Area with  low-story shopping quarters, amusement quarters and medium-story
  business quarters
H:   Dense  area packed with low-story  residential houses, stores  and factories
  mainly of textile and dyeing
I:  Typical high-story civic and business center
J:  Area sited on a spit in the estuary, with residential quarters, and commercial
  quarters, wholesale markets and small factories along a trunk road
K:   Suburban  residential area on a terrace with many company-owned residential
                                     43

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Table 1.2 (a) Summary of Surveyed District (Combined Sewer System)
Drainage
district
A
B
C
D
E
F
G
H
I
J
K
L
Drainage
system
Pumping
Gravity
flow
Pumping
Pumping
Gravity
flow
Gravity
flow
Gravity
flow
Grayity
flow
Pumping
Pumping
Grayity
flow
Gravity
flow
Drainage
area
(ha)
44.33
540.6
269.5
35.13
22.09
68.37
39.5
148.49
45.50
215.14
57.6
17.61
Population
Daytime
6,655
165,019
58,690
12,298
3,579
38,268
12,800
37,180
43,200
27,000
3,973
9,700 (day)
17,000 (night)
Resident
4,016
155,091
61,167
9,003
4,270
8,358
1,780
25,280
804
31,727
3,863
1,098
Sewer
diameter
(mm)
300-
900
a 6000 x 4325
a 4000 x 3600
Q1650x 1650
250-
1200
230-
a 1950 x 1950
250-
1650
250-
a 3000 x 1930
300-
a 2000 x 1350
250-
a 2200 x 2200
200-
02100x 1680
230-
01360x 1060
Max.
flow rate
in dry-
weather
(m3/s)
0.057
2.11
1.57
0.10
0.052
0.282
0.189
0.809
0.385
0.261
0.028
0.247
Land use
Residential
(ha) (%)
44.33 100
397.5 73.5
16.79 6.2
21.45 61.1
21.38 96.8
0 0
0 0
32.10 21.6
0 0
108.54 50.5
57.6 100
0 0
Commercial
(ha) (%)
0 0
68.29 12.6
46.84 17.4
13.68 38.9
0.71 3.2
68.37 100
39.5 100
32.86 22.1
45.50 100
41.6 19.3
0 0
17.61 100
Industrial
(ha) (%)
0 0
74.80 13.9
205.87 76.4
0 0
0 0
0 0
0 0
83.53 56.3
0 0
65.0 30.2
0 0
0 0
Road area
(ha) (%)
6.95 15.7
116.6 21.6
3.82 1.4
4.46 12.7
2.39 10.8
21.05 30.8
9.80 24.8
31.27 21.1
24.3 53.4
44.77 20.8
7.0 12.2
5.35 30.4
Impervious area
(ha) (%)
15.27 34.4
288.0 53.3
186.3 69.1
16.08 45.8
7.68 34.8
55.43 81.1
31.02 78.5
114.46 77.1
39.1 85.9
127.95 59.5
15.0 26.0
16.40 93.1

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           Table 1.2 (b) Summary of Surveyed District (Separate Sewer System)
Drain-
age
district
M

O
Drain-
age
system
Gravity

Gravity
flow
Drain-
age
area
(ha)
17.17

26.75
Population
Day-
time
9,300

2,420
Resi-
dent
2,695

3,227
Sewer
diameter
(mm)
ai200x
1030-
030x70
Q2500x
1800
Land use
Residen-
tial
(ha) (%)
8.55 49.8

26.75 100
Com-
mercial
(ha) (%)
8.02 46.7

0 0
In-
dustrial
(ha) (%)
0.60 3.5

0 0
Road
area
(ha) (%)
5.72 33.3

4.99 18.7
Imper-
vious
area
(ha) (%)
15.7 91.4

21.26 79.5
  houses
L:   Typical amusement quarters on a spit in the estuary, enticing extremely large
  night population compared with daytime one
Separate sewer survey areas
M:   Tier on  the  sea, with business quarters, commercial quarters, hotels,  public
  facilities, government institutions, multi-family residential houses
O:   Newly developed  residential area on a suburban  terrace,  with  single-family
  houses

1.3.3  SURVEY RESULTS
1.3.3.1  Water Quality Characteristics of Combined Sewer
     Summarized  in the following are the results of dry- and wet-weather water
quality survey made in  1975  of the  twelve survey areas in the eleven municipalities
in different localities in Japan.
(a)   Findings of Dry-weather Survey
     In each survey area, dry-weather around-the-clock survey was carried out once
or twice.  During the survey, sewage flow was measured  and once-every-30 minutes
sampling were conducted for water quality analysis.
     Table 1.3    shows dry-weather  average  water  qualities  and concentration
ranges in respective survey areas.
     Followings are  the water quality characteristics of respective survey areas in
dry-weather and the factor that are considered attributable to them.

C:   Industrial quarters account for 75% of total area, discharging high concentra-
  tions of heavy metals.
E:   Residential, but high in BOD, COD and SS.
H:   A good number of textile and dyeing factories in the area resulting high BOD,
  COD and SS.
I:    Typical  business quarters discharging weak effluents having a soluble-to-total
  BOD ratio of 14.4%.
K:   Low BOD; quantities of pipeline desposits are suspected to be.
L:   Densely built amusement quarters generating a large volume of sewage for the
  area; high BOD.
     While these areas have  different characteristics,  they also have something in
common with each other as follows.
                                      45

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Table 1.3 Dry Weather Average Concentration of Combined Sewage
Drainage
district
A
B
C
D
E
F
G
H
1
J
K
L
Date
Oct. 22
-23
Jul. 15
Sep. 21
-22
Aug. 26
-27
Dec. 3
Sep. 2
-3
Nov. 11
-12
Aug. 27
-28
Oct. 23
-24
Jan. 12
-13
Oct. 31
Oct. 1
Aug. 4
~5
Feb. 2
Dry Weather Arerage Concentration ("ower Ra^ ^ mg/C
BOD
136
21-560
103
23-151
127
12-229
110
35-281
134
16-374
84.8
34.7-147
122
39.5-180
93.2
7.6-205
321
66-691
101
11-180
116
14-203
51.7
6.3-123
143
21.4-297
180
31-494
S-BOD
79.9
19-468
-
42.1
5.8-72.9
82.0
17-198
49.0
4-184
31.6
9.9-53.6
36.4
10.1-63.2
47.6
4.4-132
208
44.3-311
14.5
4.0-29.3
68.4
10.6-152
18.5
4.5-43.0
56.3
10.7-109
-
COD
37.2
6.2-158
-
53.0
10.0-136
60.0
24-191
117
15-293
41.1
11.9-67
35.6
23.2-56.1
38.9
8.7-63
232
35-359
45.6
16.3-75.7
74.2
17.3-148
32.5
7.8-79.5
47.9
14-80.4
70.1
15.8-150
SS
55.0
14-163
83.2
12-157
88.3
12-205
84.8
19-258
202
8-844
76.0
26-184
79.0
27-132
64.0
13-125
120
22-194
95.7
19-202
78.2
12-187
55.8
10-145
107
35-540
100
18-203
vss
40.0
3-128
-
60.9
3-123
60.8
7-230
129
8-388
51.9
26-90
54.2
21-104
53.9
10-104
86.3
19-129
60.4
14-109
57.0
10-140
46.5
6-120
52.0
15-214
-
T-N
15.8
ND-40.6
-
14.7
5.17-27.7
21.5
12-52
21.3
10.6-60.1
12.4
5.49-21.1
13.8
6.8-28.8
11.5
3.0-18.0
15.3
9.56-29.7
17.9
1.60-30.7
21.5
11.2-47.4
11.0
4.1-35.0
15.2
4.32-26.4
22.0
5.97~32.S
T-P
4.14
0.11-18.8
-
4.31
0.94-8.24
2.05
1.0-5.5
5.20
1.6-12.5
4.13
1.4-8.7
4.06
1.6-7.6
1.46
0.29-2.20
5.04
2.08-8.20
2.57
1.01-3.42
10.6
2.7-23.1
; 3.08
1.13-7.32
2.27
0.95-3.24
3.13
0.85-5.13
Zn
0.02
ND-0.08
-
2.23
0.16-9.13
ND
0.30
0.07-0.65
0.25
0.15-0.47
0.15
0.11-0.22
0.19
0.09-0.40
0.663
0.10-1.51
0.12
ND-0.20
1.5
0.05-27
0.08
ND-0.6
0.18
0.09-0.49
-
Cu
0.017
ND-0.58
-
0.844
0.02-10.2
ND
0.03
ND-0.08
0.057
0.02-0.14
0.04
0.01-0.07
0.037
ND-0.15
0.079
0.02-0.16
0.05
ND-0.07
ND
0.013
0.007-0.025
0.02
ND-0.16
-
Pb
ND
-
0.04
0.01-0.09
ND
0.006
ND-0.05
0.01
ND-0.03
0.01
ND-0.03
ND
0.01
ND-0.04
ND
ND
ND
ND
-
Coliform
group
x 104/mC
2.91
0.05-14
-
-
80
20-280
5.18
0.5-26
6.4
1.2-9.7
6.5
2.8-9.2
77
21-260
2.4
0.011-11
17
1.5-40
5.7
1.6-20
11
0.52-38
80
1.1-820
-

-------
a.    VSS/SS is in the range of 0.63 to 0.88, except for one survey area.
b.    Three survey areas (F, G, and L) show flow rate 10 to 30% less in winter than
in  summer, and an increase in BOD of 30 to 40%  on the average  in winter over
summer.
c.    No definite differences by land use are noticed
     Table 1.4 shows daily flow and loadings per capita discharged.  In Japan, it has
been generally accepted as a sewage works planning practice that the sanitary sewage
volume and BOD load per  day per person are about 500 lit. and 60 g, respectively.
It is noteworthy that even in typical residential areas such as A and E,  these standard
values are exceeded by a large margin.

             Table 1.4 Summary of Per Capita Runoff Loadings

                                                   (Per capita per day)
District
A
B
C
D
E
F
G
H
1
J
K
L
Popula-
tion*
5,335
160,055
59,929
10,650
3,924
23,313
7,290
31,230
22,002
29,363
3,918
9,266
Flow
(2)
738
661
1,583
536
702
711
510
882
1,155
429
487
356
1,352
1,258
BOD
(g)
100
68.1
202
59.9
93.6
60.4
62.3
82.2
367
43.4
56.6
18.3
192
226
SS
(g)
40.7
55.0
140
46.6
140
55.3
40.5
56.2
140
41.1
38.6
19.7
145
126
K-N
(g)
11.7
-
23.3
11.8
-
9.09
7.21
10.2
18.1
7.68
10.5
3.94
20.5
-
T-P
(g)
3.05
-
6.82
1.13
3.78
3.05
2.15
1.29
5.88
1.10
5.35
1.09
3.06
3.93
                                                                   (Sep. 2-3)
                                                                   (Nov. 11-12)
                                                                   (Aug. 4-5)
                                                                   (Feb. 2)
* Average of Daytime and Resident Population Shown in Table 1.2 (a).
(b)  Findings of Wet-weather Survey
     Wet-weather survey was conducted two times to four times in each survey area.
i)    Wet-weather runoff and water characteristics
     Fig.  1.1 shows the relationship between total rainfall and total runoff.  The
runoff coefficient is largely influenced by the impervious area ratio.  As shown in
Table 1.2, some survey areas have a large impervious area ratio of more than 90%.
In these areas, the runoff coefficient is high.  Taken altogether, however, the runoff
coefficient lies in the range of 40 to 80%.
     Table 1.5 shows average characteristics and concentrations of combined sewage
in wet-weather conditions.
     Figs. 1.2 (a) through (d) show wet-weather BOD,  SS, T-P, and K-N in terms of
                                      47

-------
Table 1.5 Summary of Average Quality of Combined Sewage in Wet Weather
Dis-
trict
A
B
C
0
E
F
a
H
1
J
K
L
Date
1
2
1
2
1
2
3
1
2
3
I
1
3
1
2
3
1
2
3
4
1
2
3
1
2
3
1
2
3
1
2
1
2
3
Nov. 15
-16
Nov. 27
Jul. 10
Jul. 12
Sept. 23
-24
Sept. 29
Nov. 14 .
-15 '
Oct. 3
Nov. 19
Feb. 5
Oct. 24
Feb. 5
Feb. 16
Oct. 7
Oct. 24
Nov. 7
Aug. 22
Sep. 8
Sep 18
Oct. 7
Jul. 7
Aug. 6
Feb. 5
Oct. 28
-29
Nov. 6
-7
Nov. 27
Feb. 5
Feb. 18
Mar. 11
-12
Oct. 7
Nov. 13
Nov. 18
Feb. 5
Feb. 17
Rainfall
(mm)
26.5
1.0
6.5
8.3
52.0
36.0
9.1
2.25
18.50
11.07
6.5
29.0
33.0
85.8
23.1
40.1
2.5
5.0
2.5
5.0
15.5
24.0
14.2
19.5
36.0
8.0
1.0
18.0
11.0
12.5
9.5
6.0
2.8
27.0
Wet Weather Average Concentration 
-------
                        Fig. 1.1  Total  Runoff and Rainfall
                               o!2
          OH1
        0H3      OF2
  OI3M, °   ^002
     "i3oKl   °J2
0L1
        O H2


    = 11     OA1    0E3


    OM2_,_.   oE2
                                  40        50         60

                                       Total rainfall (mm)
                                                                                     90
       Fig. 1.2 (a)  Discharge Volume and Average Concentration  (BOD)
     OA2
           OG2
     0L2  0103
     -  -fi-°-o-
OD1

C3

LP* .
                  G4
                   O
                            OK2
                                                          BOD
                                OKI
                     J3
                     O
    Oil

L3  D3
                                                   OI2
                                                                                        OJ2
       13         OD2
   OE3     OH2
        OI-2
                                                                             OF3
                                     OF1
                                                                              10       11        12
                                 Discharge volume during wet-weather

                                 Discharge volume during dry-weather
                                        49

-------
              Fig.  1.2 (b) Discharge Volume and Average Concentration (SS)
        Dl
           OL1
           QA2
                                 OK2
                         OG4
    OG2

      OG3

OJ1
  OOG1

:3   .H?°QP.30.H1
                                     OKI
                         Al J3
                         O O

                            OH2
                                 OD2
                                            -Fc5.
                   "Oil
                        OF2
                                                             SS
                                                                                              QJ2
                                                                    012
                                                                                    OF3
                                                                                                    12
                                       Discharge volume during wet-weather
                                       Discharge volume during dry-weather
           Fig. 1.2 (c) Discharge Volume and Average Concentration (Total-P)
2.0
1.8
1.6
1.4
1.2
0.8
0.6
0.4
0.2
0
•
D

Total-P
^
P°"
OG3 °K2
	 « _I3___ . _..
0 ,3
OL1
QE3 Al J3 QD2
OC3 H3 O o
OE2LfO'l OKI 0]2
OF1
OD3 QF3
* OC1 OJ2
QH1
OF2 OH2
                                                                                                     12
                                       Discharge volume during wet-weather
                                       Discharge volume during dry-weather
                                               50

-------
              Fig. 1.2 (d) Discharge Volume and Average Concentration (K-N)
2.6

2.4
2.2
2.0

1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0















OK2



Kjeldahl-N



OA2
OJ1 0"
L2
5fel <->H3
On
OL1 oil OK1
^il OG2 HI OH2 012
OE2 00 OJ3
q 9D3 A1
°E3 0 K2 OF1 01-3
OD2
_ OJ2
OG4
                                    Discharge volume during wet-weather
                                    Discharge volume during dry-weather

ratios to those in dry-weather. After a light rainfall, BOD, T-P and K-N become by
some chance by far larger in concentration than in dry-weather. In case of a large
scale  storm,  however, the  concentrations are reduced by dilution effect and the
loadings are generally held within several times those in dry-weather. As regard SS,
however, the  reduction of  concentration is  far less than  others even in  case of a
large-scale rainfall.   Namely,  it remains almost the same  as in dry-weather.  This
shows that the bulk of SS is conveyed into the sewer from the ground surfaces with
unlimited sources of SS supply.
     Fig. 1.3 shows the relationships between maximum storm water flow rates and
runoff loadings of BOD and SS.
     Although the runoff loadings of BOD and SS are different by an order or so
among the survey areas, it is found that they have  a significant relationship with
flow rate.
     As is clear from above, the mean values of most of water qualities can be said
to decrease with increase in  the scale of rainfall.  However, the time change in runoff
loadings is quite complicated, and defies rendition by mean qualities only.
     Most of wet-weather records give the so-called "first flush."
     Fig.  1.4 refers to the record in the survey area E in which the cumulative flow
and cumulative loadings are  shown in percentage.
     It is highly suggestive of a large loading runoff in the early stage of rain runoff.
     It  should be noted  however that  compared  with BOD and  SS,  the loading
                                      51

-------
Fig. 1.3 (a)  Maximum Flow Rate and BOD Loadings Discharged
                                                 H3
                                                  °OB1
                                 o G2

                                OKI
                         Maximum flow rale (m3/tec)
     Fig. 1.3 (b)  Maximum Flow Rate and SS Loadings Discharged
                          Mnimum (low tile (m]/tcc)
                              52

-------
   Fig. 1.4  Cumulative Flow Volume and Pollution  Loadings Discharged
                                    A district (Wet-weather)
          16:00       20-00       000        400
                                                      8-00        1200
g.
1
|
5.  SO
                            BOD
                                    SO
                              Cumulative flow discharged
                                                            IOOOO    11427(m3)
                                        50
                                Cumulative Dow discharged
                                                                          3993(m')
                                        53

-------
Fig. 1.5 (a) Variation of Water Quality in Combined Sewage (Dry-Weather)
 Fig. 1.5 (b) Variation of Water Quality in Combined Sewage (Wet-Weather)
 o
 =?  05
                                            	BOD/COD

                                            	 VSS/SS

                                            	S-BOD/BOD
                                                                  2.0 §
                                19.00

                                  Time
                                   54

-------
runoff curves of T-P and K-N do not show so large a change with time, and this
tendency is seen in most of rainfall observations.  Hence it is inferred that the deten-
tion of wet-weather overflow by the storage tank in order to reduce pollution of
waters will be ineffective in the removal of T-P and K-N as compared with BOD and
SS.
     Figs. 1.5 (a) and (b) show changes in water quality indices in the survey area K
during dry-  and wet-weather,  respectively.  With reference to dry-weather, BOD/
COD, VSS/SS, S-BOD/BOD all are nearly constant in the daytime.
     In the nighttime when the flow declines, VSS/SS decreases while S-BOD/BOD
increases.  On the other hand, BOD/COD does  not show so conspicuous change.
In wet-weather, every index shows a large change: in  the  rising period of runoff,
S-BOD/BOD declines; in the first peak of SS runoff, VSS/SS shows no change, but
in the second peak of SS when the sewage runoff has attained a maximum, VSS/SS
falls largely.
     The  decrease in VSS/SS is considered  due to supply of SS from ground
surfaces.
     With attention paid to the fact that VSS/SS is almost  constant in dry-weather
while it changes in wet-weather, a trial is made to divide  SS runoff loading into
ground-contributed  component  and  the  sewer deposit-contributed   component
which is supplied during dry-weather.
     From the  urban storm  water  discharge survey shown in  1.3.3.2, the ground-
contributed SS is estimated at 0.2 in terms of VSS/SS.
     The results of computation are shown in Fig. 1.6.
     The first peak showing "first flush" is chiefly contributed by  SS runoff from
the deposits in  the sewer.  In the second peak, however, SS is divided almost equally
between  the deposit component and ground component.  With reference to the
rainfall shown in Fig. 1.6, the ultimate SS discharge of 674 kg is broken down as
follows.
     408 kg  (61%) by sewer deposit  runoff; 240 kg (36%) by ground supply; and
26 kg (3%) by sewage.  Namely, the sewer deposit is found most responsible for SS
discharge.
ii)   Local characteristics
     From the  viewpoint  of locality, what shows  the most highest change in wet-
weather as compared with dry-weather is the survey area K. In the second rainfall
observation in the survey area K, for example, the average concentration  is 2.7 times
in BOD as much as that at the same hours in dry-weather, 5.6 times in SS as much,
and the runoff loading is 10.5 times and 21.8 times, respectively.
     The maximum concentration is 840 mg/fi for BOD, and 2,129 mg/fi for SS.
     As shown  in 1.3.3.1,  the  dry-weather concentrations in the survey area K are
very small compared with the average concentrations in other survey  areas. It is
therefore  conjectured that a considerable amount of loadings is deposited in the
sewer  during dry-weather  and is flushed  out  in wet-weather to develop  a salient
increase in the loadings.
     The survey area K is situated on a steep with a ground slope of 24.5%0.
Considering  this high slope,  it is very queer why such deposit  is developed in the
                                     55

-------
                                          Fig. 1.6 Comparison of Solids in Wet Weather Sewage by Sources.
                                                             K district     Nov. 13. 1975
100
 80
60
 40
 20 -
    15:00
                                              /\
                              A       V      \


                                                                                                             SS,  (Solids in dry weather sewage)
                                                                                                             SS,  (Solids accumulated in sewer)
                                                                                                             SSj  (Solids from surface in wet weather)
                                                                                                                                              (g/sec)
                                                                                                                                                1.2
                                                                                  \>--=,
                                     17:00
                                                                 19:00
                                                                                               21:00
                                                                                                                              23:00
                                                                       Time

-------
sewer. The clarification of the causes is left to further study in the future.
     In contrast to the survey area K, the survey area E which forms also residential
quarters on a steep slope of 20.4%0 shows  only a bit increase in the wet-weather
runoff loadings. In the first rainfall observation in  survey area K, for example, the
average concentration is 0.78 times in BOD  and 1.02 times in SS as  much as that
in the dry-weather and the runoff loadings also remain small.
     As explained in 1.3.3.1, it is  worth  noting that in the survey areaK, SS, COD,
etc. are considerably high in dry-weather sewage.
     For  all  that the survey areas K and E  are almost the same in  land use and
geographical  conditions,  they  present  quite different phases both  in dry- and
wet-weather pollutant discharges.  In the survey  area K, it is  no doubt that there is
something promoting deposition in the sewer.
     It is therefore hoped that the causes be clarified to reflect in the engineering of
sewage pipeline system.
iii)  Correlation between water characteristics
     Figs.  1.7  (a), (b)  and (c)  show  the correlation  between the characteristics
obtained  by  the analysis of both dry- and wet-weather surveys.  Here are some in-
teresting findings.
     In many survey areas, the  ratio VSS/SS becomes smaller in  wet-weather  than
in dry-weather, and the inorganic suspended solids increase in wet-weather.
     From the  correlation between  BOD  and TOC,  it is  understood  that  the
refractory organics increases in wet weather.
     This is very important in dealing with the treatment of wet-weather combined
sewer overflow.
     Of the heavy metals, zinc is found in every survey area.  In many survey areas,
it is found that zinc has  a significant correlation with SS, though no  substantial
difference is seen between dry- and wet-weather.
1.3.3.2 Characteristics of Urban Storm Water Discharge
     Aside from the water pollution due to  combined  sewer overflow, the urban
storm water  discharge has come to be more and more recognized as  a major con-
tributor of water pollution.
     In the separate sewer  municipality, member of the  Research Committee on
Combined Sewer System  Problems, a survey area was established for investigating
urban storm  water discharge.  Survey  stations were set at the storm sewers in the
survey area M forming commercial quarters in the center of city in 1975 and in the
survey area O forming newly developed  suburban residential  quarters in 1976, for
the purpose of wet-weather storm water sampling and discharge observation.
(a)  Local Characteristics
     Table 1.6  shows the mean characteristics and concentration ranges of urban
storm water discharges observed at the two survey areas.  In the survey area M where
amusement quarters exist, the water quality is very poor; the concentration on the
average of four rainfall observations were 38.9 mg/C for BOD, 288 mg/C  for SS.
The  maximum  values were  309 mg/C and 1,180 mg/C, respectively, suggesting  that
the urban storm water discharge itself is considerably contaminated.
                                      57

-------
                       Fig. 1.7  Correlation between Water Qualities
              * Dry-weather
              ° Wet-weather
      240
1
                                           A'district

                                       (a)  SS - VSS
                      100         200
                                            300        400

                                               SS (rng/C)
                                                                     Dry-weatiier
                                                                         Y = 0.8697X - 8.889
                                                                         R = 0.990
                                                                     Wet-weather
                                                                         Y = 0.3807X+2.738
                                                                         R = 0.927
                                                                              600        700
              *   Dry-weather

              o   Wet-weather
                                                       L district


                                                   (b)  BOD - TOC
                                —I—
                                 160
—I—
 240
                                                                        Dry^weather
                                                                            Y =0.3289X +6.378
                                                                            R = 0.869
                                                                        Wet-weather
                                                                            Y = 0.5075X+ 14.49
                                                                            R - 0.903
—I—
 400
—I	1	1
 480         560
                                               BOD (mg/ii)
                     100         200        300         400


                                               SS (mg/C)
                                                                      Dry-weather
                                                                          Y = 0.0076X-0.1669
                                                                          R ° 0.868
                                                                      Wet-weather
                                                                          Y = 0.0046X + 0.2788
                                                                        0R = 0.761
                                                                  500        600
                                                                                   ~T	1
                                                                                         700
                                             58

-------
Table 1.6 Summary of Storm Runoff Water Quality from Urban Area
Dis-
trict
M
O
Date
1
2
3
4
1
2
4.6
8.6
9.8
12.4
7.19
10.20
Rain-
fall
(mm)
8.0
19.5
11.0
8.0
27.0
9.0
Wet Weather Average Concentration ({^ww: fUngT^ mg/E
BOD
56.7
7.2-142
32.1
6.9-
309
30.5
12.5-
72
62.2
9.7-
114
1.2-
12.6
2.5-
16.1
S-BOD
11.1
5.6-
17.9
9.24
4.0-
47.4
7.69
6.4-
12.5
14.3
6.1-
42.3
0.9-
3.5
1.3-
4.2
COD
43.9
9.9-
77.1
43.7
10.5-
190
40.7
17.5-
73.5
50.8
10.4-
80.8
5.1-
25.0
7.7-
25.0
SS
420
10.4-
863
303
1.1-
1180
347
20-
715
182
16.3-
280
38.0-
490
16.3-
153
VSS
91.9
4-
226
98.1
9.3-
460
71.2
14.2-
101
95.6
~
148
8.0-
61.0
7.0- •
35.0
T-N
7.23
3.75-
18.8
5.31
1.7-
25.9
3.45
2.62-
3.77
8.81
2.28-
14.9
1.17-
4.27
1.18-
7.46
T-P
0.24
0.053-
0.556
0.24
0.09-
1.45
0.41
0.36-
0.89
0.48
0.09-
1.73
0.01-
0.24
0.009-
1.42
Zn
0.956
0.11-
1.75
0.670
0.06-
1.80
0.54
0.19-
0.70
0.734
0.12-
1.07
0.042-
0.286
0.038-
0.250
Cu
0.149
0.030-
0.36
0.299
0.026-
1.93
0.12
0.01-
0.14
0.136
0.031-
0.192
0.004-
0.019
0.0067-
0.022
Pb
0.277
0.028-
0.740
0.212
0.015-
0.550
0.101
0.018-
0.130
0.114
0.015-
0.151
0.010-
0.055
0.0099-
0.034
Cr
0.025
0.004-
0.046
-
-
-
0.002-
0.009
0.0006
-0.0018
Ni
0.038
0.006-
0.057
0.021
0.004-
0.073
0.018
0.006-
0.022
0.019
0.008-
0.027
0.004-
0.013
0.0011-
0.045
Cd
0.0031
0.0014-
0.0103
-
-
-
0.0006-
0.0017
0.0005
-0.0020
Coliform
Group
x 104/m2
0.74
0.037-
4.0
0.38
0.081-
6.2
0.46
0.011-
0.71
0.88
0.042-
1.5
0.057-
0.76
0.22-
0.76

-------
     Fig. 1.8 shows the third rainfall observed in the survey area M.  It also shows
 the  relationship between the cumulative  loadings  of BOD, SS,  T-P and K-N in
 percentage to the respective totals and the cumulative discharge.
     The loading hydrograh shows a bell shape, significant of a large loading runoff
 in the initial stage of rainfall.  Just as in Fig. 1.4, however, T-P and K-N are less in
 such tendency.
     Figs. 1.9 (a) and (b) show the changes in water quality in the two survey areas.
     While  the water quality in the survey area M is very poor, that in the survey
 area O is very agreeable, proving that the water quality of storm  water discharge is
 largely governed by the local  conditions. In such a place as the survey area M where
 the  social activities are vigorous, the effect of storm  water discharge on the pollution
 of  waters cannot  be neglected, and  the separate  sewer system  may have to be
 improved some way or other in the future.
         Fig. 1.8 Cumulative Flow Volume and Loadings Discharged of Urban Starm Water

                                     M district    Sep. 8, 1975
 SS   BOD
 nig/l!  mg/t
800 -
400 -
 0 J
       80-
       40-
Rainfall
(mm/5 min)
    0
                                                                             -2.0
                                                                             -4.0
                  13:35
                              14:00
                                                            15:00
                                                                         15:25
                                  500
                                 Cumulative flow discharged (m3)
 1182
                                       60

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            Fig.  1.9 (a)  Variation of Water Quality in Storm Water Discharge (Urban Area)
BOD  0
mg/C  mVsec
                                         M district      Dec. 4, 1975
  150
  100
   50
     -0.10
     •0.10
      0.05
                                                                                               ss
                                                                                               mg.lv

                                                                                               300
                                                                                                  200
                                                                                                  100
       1.0
       0.5
   21
   
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                Fig. 1.9 (b) Variation of Water Quality in Storm Water Discharge

                            (Residential Area in the Suburbs)
BOD 0

mg/8 m3/sec


   20 Lc
 10
    1-0.1
                                      O district     Oct. 21,1976
            6:00
                                   7:00
                                                         8:00
                                                                                              ss

                                                                                              mg/C


                                                                                              200
                                                                                              100
                                                                                9:00
    1.0
    0.5
                                                                     BOD/COD

                                                                     (BOD-S-BODVVSS

                                                                     VSS/SS
            6:00
                                   7'00
                                                          8:00
                                                                                 9:00
    1.0
a
O
                                                                      BOD/TOC

                                                                      BOD/TOD

                                                                     . S-BOD/BOD
                                                                                             12.0
a
o
    0.5
                                                                                             I 1.0
            6:00
                                   7:00
                                                                                 9:00
                                                62

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(b)   Characteristics of Water Quality
     Fig. 1.10 shows the nitrogen forms in the urban storm water disclosed by the
survey of the survey area M.
     As the discharge comes  close to an end, the ratio of NH3-N is reduced, while
NO2-N and NO3-N rise.
     Fig.  1.11  shows the correlation between SS and VSS on the  one hand arid
heavy metals on the other.
     Interestingly enough, the ratio of VSS/SS is smaller than that in the combined
sewer.
     There is a significant correlation  established between SS and heavy metals.
Assuming that all these heavy metals are present in SS, a comparison between them
and the heavy metal concentrations usually found in soil shows that Zn, Pb and Cd
in SS are more than 50 times those in natural state.
           Fig. 1.10 Variation of Nitrogen Forms in Urban Storm Water Discharge
                                 M district   Apr. 6, 1975

                                            O K-N
                                            • NO, -N
                                            A NO, -N
(mg/C)
0.20
(rag/1!)
2.0
                                       63

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 •a
    640  -
    480  -
    320  J
     160  -
                       Fig. 1.11 (a)  Correlation between SS and VSS
                                     (a) SS-VSS
                           o    o
                       Y = 0.3360X+ 15.96
                       R = 0.830
                    200
                                400
                                             l
                                           600
            800
                        1000
                                    1200
l      i
    1400
                    Fig. 1.11 (b)  Correlation between SS and Heavy Metals

                                               SS (mg/C)
    1.60 -
    1.20-
r5   0.80 -
    0.40
    0.00
                                                                Y =0.0017X + 0.2281
                                                                R = 0.872
600         800
    SS (mg/C)
                                                                  1000
                                                                              1200        1400
                                            64

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              Fig. 1.11 (c)  Correlation between SS and Heavy Metals
 0.80  -
 0.60  -
: 0.40  -
 0.20   -
 0.00
                                      (c) SS-Pb
                                                        Y = 0.0005 x+0.0305
                                                        R = 0.806
                  200
400
                                          600        800
                                             SS (mg/E)
                                   1000        1200
                                                           1400
                    Fig. 1.11 (d)  Correlation between SS and Heavy Metals
                                                       Y = 0.00005 + 0.0033
                                                       R = 0.987
0.004
                      —i	r
                       640
                                                                  i	r
                                         480
                                                                 800
                                                                            960
                                             SS (mg/E)
                                                                                        1120
                                            65

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                     Fig. 1.11 (e) Correlation between SS and Heavy Metals
    0.068-
                                                            Y = 0.00005 X +0.0114
                                                            R = 0.736
    0.004
                                           —i	r
                                           600
                                               SS (mg/B)
           —I	T
            800
1000
"1	1	T
     1200
1400
                       Fig. 1.11 (f)  Correlation between SS and Heavy Metals
   0.0094 -
   0.0074 -
I
S  0.0054
   0.0034
   0.0014
                 Y = 0.00001 X +0.0014
                 R = 0.962
                                 ~iI      r
                     160
                                 320
480
SS (mg/K)
                                                        —1	1	1	1	1	1	1
                                                        640         800         960        1120
                                             66

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(c)   Characteristics of Rainfall
     Table 1.7 shows the results of rainfall analysis made in the survey area M.
     In the  urban  area, the rainfall itself is fouled with  air pollutants,  including
poisonous heavy metals such as Pb and Cd, posing serious threat to human health.

                           Table 1.7 Water Quality of Rainfall
                            M District April 6, 1975  Rainfall 8 mm
\

\
\
Concen-
tration
(mg/8)
Load
(g/ha)

COD



4.04

323

T-N



0.885

70.8

K-N



0.53

42.4

NO;-N



0.0125

1.0

N03-N



0.343

27.4

T-P



0.044

3.48
Total
residue
on
evapora-
tion

79.2

6330

Volatile



22.2

1770

Zn



0.014

1.14

Cu



0.013

1.04

Pb



0.0185

1.48

Cr



0.0026

0.208

Ni



0.0065

0.520

Cd



0.0006

0.048
     Fig. 1.12 shows the relationship between rainfalls and average concentrations
which is obtained by analyzing the quality of rainfall in Tokyo.  It is considered that
the concentrations of rainfall decline with increase in rainfall to eventually saturate
to a constant value.
     The results of the  surveys in the survey area M  and in Tokyo are in agreement
so long as the order of values is concerned.
  (mg/S)
     7
 z
 I
 X
 z
 z
 I
 o
z
 I
o"
z
•    •
     o
   o
                o
Fig. 1.12  Rainfall and Water Quality
                        O
                                    o
                        • NH,-N
                        APO.-P
                                          A
                 10
   20          30          40

         Total rainfall (mm)
                                  A
                                                           O
                                                             50
                                                                    O
                                                  (mg/C)
                                                                           0.06
                                                                   0.05
                                                                           0.04
                                                  0.03
                                                                          0.02
                                                                          0.01
                                                                                 O
                                                                                 a.
                                        67

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1.3.3.3  Summary of Survey Results
     The surveys on combined sewer overflow and urban storm water discharge in
the twelve representative cities in Japan have disclosed the following.
1)   It is generally  seen in wet-weather that BOD, T-P and T-K are diluted signifi-
cantly while SS remains no nearer being diluted.
2)   Wet-weather discharge of T-P and K-N has less to do with the tendency of "first
flush" than BOD andSS.
3)   In  wet-weather,  the water  quality  in  the  combined  sewer gets aggravated
seriously, largely different though they may be with locality.
4)   In wet-weather the combined sewer experiences an increase in inorganic SS and
at the same time an  increase in refractory organics.
5)   The urban storm water  discharge quality varies depending on land use; the
discharge from urban areas such as amusement quarters is seriously contaminated.
6)   In the urban area, the storm water itself is polluted; the degree of pollution is
high, particularly in  the early stages of precipitation.
1.4   POSTSCRIPT
     A series of surveys of which this is part will  be continued till 1973 for collect-
ing more detail data which  the authors are confident will provide something of a
basis on which to build up more improved sewer systems meeting specific conditions
of localities.
                                     68

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   CHAPTER 2.   COMBINED SEWER  OVERFLOW SIMULATION - CASE
                 STUDY ON YABATA SEWER CATCHMENT AREA,
                 TOKYO -
2.1   Introduction	70
2.2   Overflow Quality Characteristics	70
2.3   Field Survey of the Pollutants on the Source	76
2.4   Simulation of BOD Load Discharge   	77
  2.4.1   Relationship between Discharge Q and Pollutant Load Discharge Qs .   77
  2.4.2   Introduction of Basin Residue Load (S)	   78
  2.4.3   Equation of Continuity	78
  2.4.4   Initial Conditions (S0)  	78
  2.4.5   Results of Simulation	       	79
2.5   Problems and Future Prospect	85
  2.5.1   Problems   	85
  2.5.2   Future Prospect	      	85
Acknowledgement	   86
Appendix   	86
                                   69

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2.  COMBINED  SEWER  OVERFLOW  SIMULATION -  CASE STUDY  ON
    YABATA SEWER CATCHMENT AREA, TOKYO -
2.1  INTRODUCTION
     A brief mention will be given hereunder to the problem of pollutants overflow
from combined sewers.  As is well known, the  combined sewer transports domestic
waste water to the sewage treatment plant  during dry weather, and during storm
weather, stormwater  is  added to the domestic waste water.  It is impossible, how-
ever, to  send  all the water  to the sewage treatment plant because of its limited
capacity.  Therefore,  if storm water flow exceeds  a  discharge that is two or three
times as much as dry weather flow, the excess is all discharged into the river. Origi-
nally, it was considered that no harm would result, since the pollutants overflow was
diluted  to some extent; but upon execution of  such a method, it was  found that
more polluted water than dry weather  flow owing to released deposits on the sewer
was  discharged into receiving waters. Regarding the magnitude of the problem, it is
said  in the United States that the released pollutants load by storm water into re-
ceiving water should  be more or less equal to those from the secondary treatment
plant (in terms of BOD). Because of this, the Japanese government is now directing
cities to install separate  sewers.  However, since sewers in existing major cities like
Tokyo, Nagoya and Osaka are of the combined sewer type, this problem has recently
been taken  up to be solved. Nevertheless simulation of pollutants overflow was
scarcely attemped in  the past, because the pollutant  runoff pattern itself occurred
not  in a simple manner; and so far no adequate measures have been taken up.
     The Urban River Section of River Division, Public Works  Research Institute,
has been carrying out the investigation of storm  water runoff from the  urban area
since its inception 1969 with the cooperation  of the Tokyo Metropolitan Govern-
ment.  From 1972 onward, the section has also been sampling and analyzing com-
bined sewer overflow. Fortunately, the section was able to propose the simulation
model of storm water runoff in  1973 and succeeded  in the simulation of the pollu-
tants runoff in  1975.  Although  the betterness  of fit  of the simulation still requires
to be ascertained by applying it  to the other basin, it has been decided to report on
the simulation as it is at the present stage,  to solicit the criticism of readers.
     It may  be necessary to be added here that the present report is concerned only
with BOD.
2.2  OVERFLOW QUALITY CHARACTERISTICS
     Since there are many detailed reports on  the characteristics of overflow from
the combined sewer, only their essence is extracted here for lack of space.
     First, Fig. 2.1 ~ 2.3* show examples of  observed hydrograph, pollutograph,

*  The peak discharge of 49 m3/sec. On 10th November, 1973 in Fig. 2.2 is nearly equal to the
   design discharge.

                                    70

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and  concentration of BOD at the Yabatagawa Basin.  In these  figures, it  may be
pointed out that conversion from rainfall to runoff (Q: m3/s) indicates comparatively
simple  correspondence, but  then  the relation between the concentration of BOD
(C: mg/1) and BOD load discharge (Qs = CQ:  g/sec) is somewhat complicated.  As a
result,  sampling intervals,  from  the initiation of runoff  to the peak is short.  For
comparison, patterns during dry weather are also indicated by  broken lines.
          Fig. 2.1  Example of Observed Overflow Characteristics {Yabatagawa, Tokyo)
         R (mm/hr)!

             20-
                                                  Aug. I, 1973

                                                  Rainfall intensity
                                                  Aug. I, 1973
                                                               Observed discharge
                                                            	Dry weather flow
                                                               Observed BOD load discharge
                 IS 16 17 18   19 /\ 20   21   22   23
                                                                 9 10 II 12 13
                                                                   r/\
                                                     Observed concentration /  *
                                                	Dry weather con-   /
                                                              Observed concentration of SS
                                                         	Dry weather concentration of SS
                                                              Observed SS load discharge
                                                              Dry weather SS load discharge
              14 15 16 17 18   19   20   21   22   23  24    123456789 10 11 12 13
                                           71

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      Fig. 2.2 Example of Observed Overflow Characteristics (Yabatagawa, Tokyo)
R (mm/hr)

     100  -.
      50
                                                               Nov. 10, 1973
                                                               Rainfall intensity
  Q
     40

     30

     20

     10
  BOD
  (mg/C)
    300
  BOD
  (g/s)
   1600
                     Nov. 10, 1973
                                                              Observed discharge
	Dry weather flow
         Observed concentration
                                                      	Dry weather concentration
                                                    Observed BOD load discharge

                                             	Dry weather pattern

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                                     Fig. 2.3  Example of Observed Overflow Characteristics (Yabatagawa, Tokyo)
 Q    BOD
(m3/s)(g/s)
   5 -
	Aug. 24, 1973
	July 12, 1973 (Dryweather)
                          16 17  18 19 20 21  22 23  0  1  234
       13 14
                                                                                                        14
                                                                                                                 15
                                                                                                                         16 17  18 19 20 21 22  23  0

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     These exmples clearly  show the high BOD concentration at the initial period
(so-called  "first  flush") and the condition in which BOD load discharge does not
decrease even if the  magnitude  of runoff increase (this condition cannot be ex-
plained by dilution alone).  As for the reason, a concept is generally accepted that
deposits accumulated on the  sewer during dry  weather are transported by storm
water.  In  this respect, the Report on Storm Water Investigation at Northampton*
is  famous for verifying this concept by discharging a large quantity of clean water
into the sewer during dry weather.  Pollutants from the ground surface will be dealt
with in Chapter 2.3.
     The  observed  values of BOD  load  discharge are plotted  with Q on  a loglog
scale according to the sequence of observations, and the curve  naturally indicates a
clockwise loop (Fig. 2.4 ~ 2.6). This phenomenon is understood to be the result of
a decrease in the pollutant load deposited in the sewer (S), by storm  water.
                         Fig. 2.4 BOD Load Discharge ~ Q
                                (Yabatagawa, Tokyo)
                                  Aug. 4. 1973
                                                     Q
                                                     (m'/s)
   This report is one of the classics on this problem and worthy of a perusal.
                                      74

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   Fig. 2.5 BOD ~ Q (Yabatagawa, Tokyo)
Fig. 2.6 BOD ~Q (A city)
                            Q(m'/s>





BOD
(I/I)
-1000
- 800
— 600

	 200
— 100

40
Aug. 6, 1975






















47
° C








4
P
c






k
•MI
°44
£5






'V
17
0,, /
V ^
38^
r/0








15^Q3
O\_

p1^
0)0°







X

27
CK












A
0
x












1
N
0i
05"













22
3






















     Another important phenomenon is that the pollutant load discharge during
 about one or two days after the termination of runoff becomes smaller than the dry
 weather load discharge.  Considering that this phenomenon was found  in older
 records, the  author sampled  and analyzed the load discharge for 12 to  24 hours
 after the termination  of runoff in fiscal 1973 and this phenomenon was observed in
 every  example analyzed.  For the interpretation  of this phenomenon, variation in
 the dry weather load  can be considered, but according  to the result of observations
 so far conducted, the dry weather pattern is comparatively stable,  if a  season is
 fixed.  Therefore, the cause of the phenomenon is considered to be re-accumulation
 of dry weather load,  that is,  the recovery of the deposits. This accumulation may
 occur in the  following way: Judging from the fact that  the accumulation also seems
 to occur  during  later stage of runoff,  it is inferred that gravel mounds  and pits
 located on the sewer pipe act as a sort of load accumulation potentials, and even if
 the discharge at the later stage of runoff is a little greater than dry weather flow,
 pollutant  load may accumulate on the gravel mound and in  the empty pits on the
 sewer pipes.  This can be easily understood if you imagine gravel pits of catch basins.
     Finally,  as for the pollutant load balance for one rainfall  or during  a certain
period, 10 days' continuous water sampling and analysis were carried out  for fiscal
 1974 and 1975 on the basis of the survey results  for fiscal 1973.  The result of the
field survey for fiscal  1974 is shown in Fig. 2.7. Regarding BOD, the pollutant load
is more or less balanced, if+4.87 tons for about 1 day from 3rd to 4th July, 1974 is
ignored.  The same results were  obtained  in the survey for fiscal  1975. From the
above, it is observed that pretty high accuracy can be expected of the simulation of
BOD, even if  supply of pollutants from the ground  surface is ignored.
                                      75

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              Fig. 2.7 Comparison with Dry Weather by 10 Days Observation
                     (Yabatagawa, Tokyo)
BOD,
(E/s)
  150
               + 1.02
                                        Hatched: BOD load due to storm runoff
                                        Unit:   ton
                                                        16     I!  19    12 2024
7/4
July 4
7/5
7/6
7/7
7/8
7/9
7/10 7/M
7/12
7/13
July 13
2.3  FIELD SURVEY OF  THE POLLUTANTS ON THE SOURCE
     As can be understood  from the above-mentioned observation, deposits of pol-
lutants on the basin and, particularly on the sewer, are playing a considerably impor-
tant role.  For this  reason, a field survey of pollutants on the sources has been
carried out. Yabatagawa basin was also chosen for the field survey. The area is 5.4
km2 and is mainly residential. Its population is about 140,000 and population den-
sity  is 260 person/ha.  Detailed explanations on the survey are omitted here, and
only the results of the survey so far conducted are shown in Table 2.1.  An example
of the survey is shown below for reference. In the case of survey on sewer manholes,
300 manholes  were randomly sampled out of 6,000 manholes in the basin concerned
and the number of the existence of pollutant deposits was checked and  the quantity
and quality of part of deposits were measured, thereby estimating the pollutant load
for 6,000 manholes.  In the case of the street surface, pollutant load was estimated
from water sprinkling tests  at only three places.  From the results of the survey, it
was found  that the load potential at this point of time was around 5 tons and the
deposits on the sewer accounted for the main part of the load potential, as shown in
Table 2.1.
                 Table 2.1 Sources of BOD Load in the Basin (Surveyed)
Location
Street Surface
Street Inlet
Sewer
Sewer Man Holes
House Inlet
Pervious Area
Total
Accumulated Load
(ton)
0.66
0.77
0.33
2.5
0.0
0.05
4.31
                                      76

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2.4  SIMULATION OF BOD LOAD DISCHARGE
     Various characteristics  which were used for simulation are briefly described
here in the order of the equation of motion in items 2.4.1  and 2.4.2 and the equa-
tion of continuity for pollutants in item 2.4.3.
2.4.1  RELATIONSHIP  BETWEEN  DISCHARGE Q AND POLLUTANT LOAD
       DISCHARGE Qs
     It Was pointed out by the author earlier that the relation between discharge Q
and pollutant load discharge Qs can be expressed by Qs a Q for BOD if the loop is
ignored and the result is averaged, and Qs « Q2 * for SS, in which the loop charac-
teristics are weak owing to its properties. In dry weather, however, these relation-
ships were not strictly  maintained and particularly at night, a rapid decrease of Qs
became remarkable. All the  observed values for fiscal 1974 totaling 500 are plotted
in Fig. 2.8.  Judging from this figure, it is clear  that something like a concept of
critical tractive force in sediment load had better be introduced.

                           Fig. 2.8 BOD-Q (for 1974)
                                 (Yabatagawa, Tokyo)
     The relationship can be expressed by the following equation.
         Qs = K'(Q-Qc)	(1)
     It is better not to think too seriously about what discharge should be taken as
Qc.  Just consider as Qc the lowest hourly discharge at the location concerned at
dawn when the flow rate  at each point in the basin drops and pollutants become
difficult to move.

*  This expression agreed with the formula for suspended sediment discharge. For instance, refer
   to "Applied Hydraulics" Vol. 2,1, p.27.
                                      77

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2.4.2   INTRODUCTION OF BASIN RESIDUE  LOAD  (S)
    As pointed out earlier in the item  dealing with overflow quality characteristics
and taking into consideration the results of water sprinkling tests on the street sur-
face  and sewer conducted by our section,  a  concept of basin residue  load  (S) is
introduced and Qs can be expressed as follows;
         Qs = K"Sm 	  (2)
     The quantity  S  can be defined as the total load in the basin that  can be dis-
charged out of the basin at each instant, and as can be seen from eq. (2),  the smaller
S becomes, the smaller will be Qs.  Particularly when m > 1, the decrease becomes
very rapid.  Values K" and m will have to be obtained by simulation. Naturally this
value S should not widely differ from  the results of the field survey of pollutant
sources mentioned earlier.  From items  2.4.1 and 2.4.2, we can obtain an equation
of motion as shown below:
         Qs - K Sm  (Q - Qc)	  (3)
2.4.3   EQUATION OF CONTINUITY
     Next, we need an equation  of continuity, i.e., an equation which traces varia-
tion in time of the basin residue load.
     This equation can be written as follows:
         dS/dt = DWF -Qs    	  (4)
     and by approximation
         AS = St+At  - St = (DWF - Qs)At               	(4')
            _ DWFt + At + DWFt    Qs,t+At-Qs,t                    ^.,,
                       Z*                  £,
     In eqs. (4) ~  (4"), DWF means dry weather BOD load discharge into the basin
(Input), and observed values of BOD load discharge  in dry weather are  substituted
for this supply because there is no other proper data of this kind.
2.4.4   INITIAL CONDITIONS  (S0)
     Eqs. (3) and  (4) are  already given.  If Q is given from the  observed value  or
rainfall runoff analysis, and an initial basin residue load (S0) at the starting point of
calculation is given, calculations can be made successively.
     The value S0 was obtained this time in the following way:
     Namely, first, the values of exponent m and K  with respect to pollutograph in
storm  weather were  obtained  approximately, and these values were applied to the
data in dry weather (16 to 18 July, 1974).  Then it  was found that an equilibrium
was reached within about  1 day  irrespective of the magnitude of S0 at initial time,
and an  S-curve in dry weather was obtained. The values of constants were obtained
by a trial and error method  and  first exponent m was almost uniquely determined
from the load  discharge characteristics in storm weather  and then there  was almost
no room for  changing  K.  This  was probably  due to so many constraints such as
average load and amplitude in dry weather.
     The result of  simulation is shown in Fig. 2.9.  In Fig. 2.9 the range of S spreads
from 4.5 tons to 5  tons. This figure unexpectedly shows near correspondence  to the
result of the field survey of pollutant sources.
                                      78

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         Fig. 2.9 Simulation of Dry Weather BOD Load Discharge (Aug. 7 ~ 9,1974)
                (Yabatagawa, Tokyo)
                          Discharge
                                                            Aug. 7-9, 1974
;200  -  ^
               /  (S0 = 4.95 ton)
             "x Computed BOD
                 v-_^?
                                           Observed BOD load
                                           discharge
 w
 E   1
               (Aug. 7)
                                            (Aug. 8)
•5S
  200
           (S0 = 4.95 and 3.0 ton)
Q
O  100
CO
        / (S0 = 4.95
      —L^z	~:
1 	
»— ^-- — ^*^ — ~~~
\
S0 =4.95 and 3.0 ton
i i i i i i i i i i 	 j 	 i 	 i 	 i 	 i 	 i 	 i 	 i 	 i 	 i 	 i 	 i 	 i — i — i


, i i ,
    16   18   20   22   24
      (Aug. 8)
                                 4   6    8   10   12  14  16   18   20
                                (Aug. 9)
     If values of K and m are determined, there is another way to determine the
value of So  which will agree with the observed value at the initial stage (sometimes
this method gave better agreement).
2.4.5   RESULTS OF SIMULATION
     Figs. 2.10 ~  2.14 show the results of simulation with m  =  2.0,  K = 11.43,
Qc = 0.87 m3/s (for fiscal 1974) and m = 2.0, K = 4.12, Qc = 0.6 m3 /s (for fiscal
1973) and using S at the same clock time in dry weather of Fig. 2.9 for So. Fig. 2.10
shows the results of continuous sampling for 10 days from 3rd to 12th July, 1974
and gives comparatively satisfactory results.  It indicates good agreement for storm
weather and clearly expresses the decrease in  BOD load discharge (recovery of de-
position) after rainfall.  Values of observed discharge are omitted from  Fig. 2.10 for
lock of space. Variation of S in time is also  shown in Figs. 2.11  ~ 14, and rapid
decrease during storm and slow recovery can be seen.
                                       79

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                Fig. 2.10 Simulation Result of 10 Days' Observation
                         (Yabatagawa, Tokyo)
                                                                  Observed
         \7     18  19      20   22     02
11    13    15   17    19 20     21       22    0
                                       80

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                      Fig. 2.11  Simulation Result (Yabatagawa, Tokyo)
                                                                                   Observed discharge
                                                                                   Dry weather flow
                                                                                         Observed concentration
                                                                                   Observed BOD load discharge
                                                                           	Computed BOD load discharge
                                                                           	Dry weather BOD load discharge
                           Computed basin residue load
12    13    14    IS    16    17    18    19 20 21 22 23 24 1  2  3  4  5  6  7  8  9  10 II 12 13  14  15 16 17 18  19
                                                 81

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                    Fig. 2.12 Simulation Result (Yabatagawa, Tokyo)
                                                    .        Observed discharge
                                                    	Dry weather flow
BOD
(mg/S)
  300
                Observed concentration
        	Dry weather concentration
BOD
(g/s)
  1600
	Observed
	Computed
	Dry weather pattern
                                            Computed basin residue load
S(ton)
                                                                          15
                                        82

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                                                    Fig. 2.13  Simulation Result (Yabatagawa, Tokyo)
00
      Q(m3/s)
       BOD
       (g/s)
         800  -
                                                                                  Aug. I. 1973
                          • Observed discharge
                                                                                                             	Dry weather flow
                       Observed BOD load discharge
                   	Dry weather BOD load discharge

                       Computed BOD load discharge
      S(ton)
                                                         Computed basin
                                                         residue load
                14    15     16    17    18     19     20    21    22     23    24
—I	1	1—I	1—I—I	1	1	1	1—I	1	1_
 2   3  4   5  6   7   8   9  10 11  12 13 14  15

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                    Fig. 2.14 Simulation Result (Yabatagawa, Tokyo)
Q
(m3/s)
    6

    4

    2


BOD
(g/s)
  800

  600

  400

  200
S (ton)
    8

    6

    4
                          Aug. 10, 1973
                                             	 Observed discharge

                                             	Dry weather flow
                                           Observed BOD load discharge
                                  	Dry weather BOD load discharge
                                       —  Computed BOD load discharge
              Computed basin residue load
        16
17
18
                       19
                             20
                     21
                          23
                                                  24
                                                 234  567
     What poses a problem here is the difference in the values of constants between
the simulation for fiscal 1973 and that for fiscal 1974. A little examination on this
matter here will be justified. What should be first pointed out is that there is a dif-
ference between load  discharge characteristics both in dry and storm weather for
fiscal 1973 and fiscal  1974.  First for dry weather, the average load discharge  in
fiscal 1973 is 149  g/s (BOD), whereas that in fiscal 1974 is 94 g/s (see Fig. 2.7), and
the reason for this is unknown. The petroleum crisis may be a partial cause, but is
considered insufficient  to  cause such a change.  In addition, dry weather flow has
hardly changed. The method of chemical analysis does not offer any cause.  Next
for storm weather,  total load for one rainfall event for fiscal 1973, for instance, is 3
to 4 times as large  as that for fiscal 1974.  The cause for this  is also not clearly
known. One of the conceivable causes is that pebbles which has caused deposits on
the sewer, were washed away  by the great  Hood  close to the design discharge on
10th November, 1973  (Fig. 2.3) and, as a result, the basin residue load potential for
1974 seemed to be reduced. This interpretation is not unfounded, because the range
of S that  was obtained  by  the simulation of the curve for dry weather in fiscal 1973
                                       84

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was 6.0 to 9.7 tons and the results of simulation made by using this value of S show-
ed a good fit to observed values. It may be added here that the observed maximum
value of total load for one rainfall event was 8 tons (BOD5) on 15th July, 1967 and
on 10th November, 1973, and the field survey of pollutants source had been carried
out since the beginning of 1974.
2.5  PROBLEMS  AND FUTURE PROSPECT
     Although several problems are left unsolved, the simulation results are satis-
factory than were expected.  Hereunder several problems are pointed out and future
prospect is reviewed for reference' sake.
2.5.1  PROBLEMS
     a.  The first tough problem is that it  should be remembered that the simula-
        tion is successful only for the Yabata basin. Further verification of the
        model must be made by applying the simulation to the other basins. Since
        the basin is located on a plateau, future investigation has to be made on the
        sewered area with old pipelines and pumping stations. Such field investiga-
        tion costs much and  is very difficult  work.  However, if a field survey of
        pollutant sources and two or  three times of field sampling can accomplish
        the work, this simulation model will be greatly beneficial.
     b. The difference in survey results  between fiscal 1973 and 1974 poses an-
        other tough problem, which  has to be  checked in future.  If deposition
        characteristics of pollutants in the  basin (K and exponent m for S) should
        be assumed to change, the problem will  become too difficult to be solved.
     c.  In this simulation, the component  of BOD, that is, the existence of S-BOD
        (Soluble  BOD), for instance, has not been given much attention.  But there
        should be a model in  which a  part of such BOD does not contribute to the
        deposition  and flows down. The supply from the ground surface also has
        to be included. It will be examined in the simulation of SS.
     d. Regarding  the problem that  the substance  of BOD may vary  from dry
        weather to storm weather, various checkings were effected by analysing the
        deoxygenation coefficient, COD and  TOC both  for the dry and  storm
        weather, but there were hardly any  differences between them.
2.5.2  FUTURE  PROSPECT
     a.  In this method,  simulation can be carried out if the characteristics of the
        total basin load including S0 and data of storm water discharge are available.
        The data of the discharge can  be obtained from the rainfall data by using,
        for instance, the modified RRL method, which has  been verified at the
        Yabata Basin and others. In such a case,  simulation can be carried out with
        S0, rainfall data and the formula of Qs.
     b.  In this sense, simulation of the  prevention measures of combined sewer
        overflow  can be carried out, by using the rainfall data for about 10 years in
        the past,  if the formula of Qs and data  concerning S0 are given. At present,
        trial calculations are being made in respect to an increase in the dilution
        ratio and  the retarding basin, etc.
                                     85

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     c.  Even  if simulation for 10 years and consequently simulation for counter-
        measures are carried  out, it is a problem to determine what  extent  the
        countermeasures should cut off the pollutants over-flow to.  At present,
        there  are neither the standards nor the criteria to determine this matter. In
        future, its effect upon receiving waters should be investigated.
ACKNOWLEDGEMENT
     In  1967,  the Sewerage section of P.W.R.I. started investigation at the Yabata
Basin.  In 1969, the work was succeeded by the Urban River Section.  Since then,
with the cooperation of many persons, a large number of results were obtained in
studies concerning urban runoff and pollutants discharge.  Particularly, the author is
grateful to the personnels of the Planning Department of Sewerage works Bureau,
Tokyo Metropolitan Government for their generous financial assistance given to him
in carrying out the studies. Out of these officials, the deepest gratitude of the author
goes to Mr. Nagaharu Okuno, who is now with  the Sewerage Works Agency, for his
kind assistance and valuable  advice. This paper is dedicated  to him.   Beside the
above, the author would like to take this opportunity of expressing his deep appre-
ciation to all the stuff of the section who gave their assistance  and advice to him in
carrying out the studies.
                                 APPENDIX

     After this paper was completed, the same simulation procedure described above
was applied to the other two catchment area.  (A and B cities)  Fig. 2.15 ~ 2.24
show results of the study.
                     Fig. 2.15 Simulation Result (Dry Weather)
                             A City, Oct. 23, 1975
                                                            Computed value
                                                            Observed value
100 -
'3  '4  "  '«  "  18  .9  20
                                 20  2   22  23  24  ,    2   ,  4  V
                                                                 6789
                                      86

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        Fig. 2.16  Simulation Result
                  A City, Aug. 6,1975
Fig. 2.17  Simulation Result
          A City, July 7,1975
  14-00    15-00     I600     17.00    IB 00     ><> 00     20:00
                                                          10-00    I LOO     12.00    13:00     14:00     15:00
(g/sec)
  700
  400
                                Fig. 2.18 Simulation Result
                                          A City, Feb. 5, 1976
                                                                                            13
                                                  Time
                                               87

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                                Fig. 2.19  Simulation Result
                                          B City, July 19, 1976
BOD
loading
(g/sec
 I 50
 I 00
                                                                                     C   M  N
                                                                o  Observed value
                                                                   Computed value   900   2   !
                                                                   Computed value   100   2   1
                    13 00
                                             14:00
                                                                       15:00
                                    Time

-------
                 Fig. 2.20 Simulation Result
                           B City, Aug. 2,1976
BOD
(g/s)
300
250
                                          •	• Observed value
                                          	Computed value    900
                                          	Computed value    100
200
150
100 _
50 -
                                                                         M   N
                      15:00
                                              16:00
                                 Time
                                    89

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ID
o
        BOD
        loading
        (g/sec)
         300
         200
          100
                    f

              b-o-ooo
Fig. 2.21  Simulation Result
          B City, Aug. 26,1976
                                                                                                                     M   N
                         Observed value
              	Computed value    900
              	Computed value    100
0.53
1.44
                 10:00
                                             11:00
                                                                        12:00
                                                                                                    13:00
                                                                                                                                14:00
                                                                                                                                                           15:00

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     Fig. 2.22  Simulation Result
               B City, Sept. 18,1975
BOD
(list

 100-
         •	. Observed value
         	Computed value    900
               Computed value    100
M   N
                  Fig. 2.23 Simulation Result
                           B City, Sept. 8,197S

                                            C    M
                                                BOD
                                                (I/I)
                    •	•  Observed value
                    	Computed value    900
                          Computed value    100
N

1
1
                              Fig. 2.24 Simulation Result
                                       B City, Oct. 7,1975
                        BOD
                        Ig/s)
      .	. Observed value
      	Computed value    900
      	Computed value    100
                                                                        M   N
                                            91

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                   FIFTH US/JAPAN CONFERENCE
                              ON
                  SEWAGE TREATMENT TECHNOLOGY
                         PAPER NO, 3
STUDIES ON SLUDGE TREATMENT
      APRIL 26-28,  1977
        TOKYO,  JAPAN
   MINISTRY OF CONSTRUCTION
     JAPANESE GOVERNMENT

             93

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              STUDIES  ON SLUDGE TREATMENT
1.  PERFORMANCE AND  EVALUATION OF MECHANICAL SLUDGE
   DEWATERING FACILITIES IN YOKOHAMA CITY	  95
      S. Miyakoshi, Yokohama City
2.  SLUDGE CONDITIONING BY  USING  HYDROGEN PEROXIDE	122
      K. Tani, Osaka City
3.  SURVEY OF  ECONOMICAL  AND TECHNICAL  PERFORMANCE
   FOR EMISSION CONTROL EQUIPMENT INSTALLED WITH
   SLUDGE INCINERATOR 	137
      Dr. A. Sugiki, Japan  Sewage  Works Agency
4.  STUDIES  ON SEWAGE SLUDGE PYROLYSIS	.163
      Dr. M.  Kashiwaya, PWRI, Ministry of Construction
                               94

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                           CHAPTER 1
              PERFORMANCE AND EVALUATION  OF
         MECHANICAL SLUDGE DEWATERING FACILITIES
                       IN YOKOHAMA CITY
1.1   Present Status of the Mechanical Sludge-Dewatering Facilities  	  96
  1.1.1   Explanation of the Facilities 	  96
  1.1.2   The Reason of Selecting the Machines	101
  1.1.3   Maintenance  	101
  1.1.4   The Results of Operation   	103
  1.1.5   Operation and Maintenance Cost	107

1.2   The Relation between the Feed Sludge and the Dewatering Efficiency ..  . 107
  1.2.1   TS and VTS	108
  1.2.2   Dewatering Rate and VTS  	108
  1.2.3   Dosing Rate and VTS  	108
  1.2.4   Water Content and VTS  	109

1.3   Evaluation of the Dewatering Machines	113
  1.3.1   The Range of the Comparison 	113
  1.3.2   The Method of Determining the Capacity of the
        Dewatering Machines	113
  1.3.3   Evaluation 	117
                                 95

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             PERFORMANCE  AND  EVALUATION OF
        MECHANICAL  SLUDGE DEWATERING  FACILITIES
                       IN YOKOHAMA CITY
     According to the sewerage plan of Yokohama City, the total city area will be
divided into nine treatment districts wherein ten sewage treatment plants are to be
erected.
     Five treatment plants are already in operation, where the secondary treatment
by the activated sludge process is carried out.
     As to  the sludge treatment,  thickened sludge (mixture of raw primary sludge
and waste activated sludge) is processed by anaerobic digestion followed by dewater-
ing in two treatment  plants, by wet air oxidation followed by dewatering in a treat-
ment plant and by dewatering of thickened sludge in other plants.
     The amount of the sludge  cake produced in five  treatment plants is  about
9,700t per annum as  solid (48,150t as wet cake), 95% of which (9,160t) is disposed
for land fill in municipal refuse disposal area as  sludge cake and the remaining 540t
is used for reclamation to agricultural land and green field as sludge cake or after
mechanical sludge drying.

1.1  PRESENT  STATUS OF THE MECHANICAL SLUDGE-DEWATERING
     FACILITIES

1.1.1  EXPLANATION OF THE  FACILITIES
     In city's dewatering facilities are installed belt-discharge vacuum filters (which
will be referred to as  BVF hereafter), pressure filters (an HPF refers to the horizon-
tal type and a VPF the vertical type hereafter.  A PF includes both of them)  and
centrifuges  (which  will be denoted an SD hereafter) as the flow  sheets  of sludge
treatment in respective treatment plants in Figs. 1.1 ^4 show. In BVFs and PFs are
installed inorganic coagulant (ferric chloride, carbide slurry) dosing devices shown
in  Fig. 1.5  and  in SDs polymeric coagulant  dosing devices shown  in Fig. 1.6. The
types of  auxiliary devices are markedly different depending upon the types of the
machines as shown in  flow sheets in Figs. 1.7 ^ 10 and a list of facilities in Table  1.1.
The process  of installation of the dewatering facilities  and  the present treatment
capacities in respective treatment plants are shown in Fig.  1.11.
                                    96

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           Fig. 1.1   Flowsheet of Sludge Treatment in Chubu S.T.P.
            Sludge  \ThickenedSluclge
           Thickening '	=-•
Waste Activated \ Tank
Sludge
                                    Elutriated Sludpe
Inorganic
Coagulant
Dosing Device
Dosed Sludge

Vacuum
Filtration
Equipment
          Fig. 1.2    Flowsheet  of  Sludge Treatment in  Nambu  S.T.P.
                                                                     — -=•- to Sludge D'rii
Inorganic
Dosing Device
Dosed
Sludge

Vacuum
Filtration
Equipment
                                                              Sludge
                                                              Cake
                                                                                i Sludge Dm
   Fig. 1.3   Flowsheet of Sludge  Treatment  in HOKUBU  S.T.P.
 Raw Primary
 Sludge      / Slud|
            Thickei
 Waste Activated \  Tank
 Sludge
               L
   Fig. 1.4    Flowsheet  of  Sludge Treatment in  the Second  Totsuka S.T.P.
  Raw Primary                .^
  Sludge       /  Sludge \s|udge 7 Sludge
    -i	»-( Thickening    W  Storage
  Waste Activated  \  Tank  /     \ Tank
  Sludge
Dosing Device
Dosed
Sludge

Virtical Type
Pressure
Filtration
Equipment
Sludge
Cake
	 =
                                         97

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        Fig. 1.5  Flowchart of Inorganic  Coagulant Doting  Device
                                                                                         Fig. 1.6   Flowsheet of Polymeric Coagulant Doting Device
Carb
Star


•H
de Slurry
»ge Tank
tl
Chloride
Storage
Tank
Q
q
Carbide 1
Slurry
Tank
fe
LL&J
Carbide Slurry
Feed Pump
Ferric Chlonde
• Resolution
• Tank
1— £P— '
                                    4-
                                    I
                                   Floculation Tank
                                 *1 Carbide slurry, which is waste acetylene
                                   sludge, contains 2(H 25% of slaked lime.

                                 •2Fernc Chloride is added as a 37.3%
                                   solution.
                                                                                              - •
                                                                                             [*J
                                                                                                           Constant Feeder


                                                                                                     -I-   Resolution Tank
                                                                                                                   I    [_   	   to Centrifugal
                                                                                                                 *|__  Jfc   Separation Equipment
                                                                                                                   A ents
                                                                                                                 Service Tank
     Fig. 1.7   Flowsheet of Vacuum Filtration Equipment

                 Treated Sewagef
from Flocculation Tank
                                                                                           Fig. 1.8  Flovnheat of Centrifugal Sflparation Equiprnfirrt
                                                            H"PP"
                                                                                              Treated Sewage
                                                                                                               Cleaning Water
                                                                                                    Coagulant Feed Pump
                                                                                  from Agents Service Tank     f-~^—^


                                                                                  from Sludge Service Tank



                                                                                                        Feei Pump
                                                                                                                                               to Hopper
Fig. 1.9   Flowsheet  of  Horizontal Type Pressure Filtration  Equipment


                                                        Oil Pump Unit
ized
Feed Blow
Back Blowl
L i c

III
HPF
III
I
1


Slud

V
r
geCake
J

                                                          - to Hopper
                                                                                    f|8 , 10
                                                                                        Irom Floccu a[ion
                                                                                     Compressor
                                                                                        Treated Sewage
                                                                               Treated Sewage
                                                                                                        of virtical Type Pretsure Filtration Equipment


                                                                                                               Filtration Pump
                                                                                                                                          Hopper
                                                                          98

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  Fig. 1.11   Time Course of  Installation of the Dewatering  Machines in
              Respective Treatment Plants
\FV
S.TPS


3
£>
3
s:
t_>



3
.O
E
ca
z





3
£3
3
2t
0
X



'M
8l
iU O
WH

Kohoki
'62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77
1
1

SVF [''BVF '•'•'•'•'•'•'•'•'•••'••••••••••••••.•.•.•.'.•.•.•.•.•.•.•.•.•.•.•.•.•. '
I'BVF ••'•'•'•'•'•'•'•'•'•'••••••••••.'.•.•.•.•.•.•.•.•.•.•.•.•.•.•.•. '
I'BVF'.'.'-V. '.•.'.•.•.•.•.•.•.•.•.•.•.•.•.•.•.•.•.•.•.•.•.•.•
1
1
. -BVF-. •.•.•.•.•.•.•.•.•.•.•.•.-.•.•.•.•.•.•.•.•.•.•.•.•.•.•.•. •
_. BVF-. •.-.•. •.•.•!•!•!•!-. •!•'•'•!•'•'•'•'•'•'•.•.•.•.•.•.•. •!•
•!BVF>;-;-;-;-;-;-;-;-;-. •.•;•;•;•;•;•.
.-.so.'. •.•.•••••••.•••.•.•.•
•• 'SD.'. •••.•••. ••••••

-.'•so ;•;•;•;•;•;•;•;•;

:-'HPF-'-'-'-'-'-'-'-'-'-'-'. •••.•.•••••••••••••••. •••••••
.'.HPF'. •.•.•.•.•.•.•.•.•.•.•.•.•.•.•.•.-.•.•.•.•.•.•.•.•.
•.i#f ••••••••••.•.•.•.•.•••••••••••.•.•
.'HPF-'.'. •.'.'.
.'HPF.'. •.'.'.',
1
1
I1 V ft, -,'.'.'.'.'.'.'.*
1 L ' VPF. •^•J'. •.'.'. •.•-•!
LYf£i

! VPF'
1 j — r — «
[VPF



- 0
<;

- 0
- 5
-10
-15
-20
-25
30

-
- 0
- 5

-10




n
- 5
* A scale on the right represents the treatment capacity of ton of the treated sludge dry solids per day.
 SDs are assumed to run 24 hours a day and others 7 hours a day. The working ratio is assumed to be 0.8.
 The treatment capacity per hour is taken after the previous results of the city.
                                           99

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                                Table 1.1  The List of Dewatering  Facilities in Respective Treatment Plants
o
o


f;
I
£
1







£,
I
" -
t " °
S5
\
5"
•< — x --<
S (, J
I |*3
a = »-
1 |l
(,'hubu Sowagp Tipulrnenl Plant
Ty,ie Bell -Discharge
Vacuum P. 1 ler
/)
J.r> m(V)
Ki.lai iniiBt 0. li - 0.'> r|Kii
Filter Cloth Polypropylene
Numbrr ) uni ! s
(DevmerinR Equipment)
Pi 1 I rale Hump 3
The- Other Pumps 6
AJ T Compressor
AgHiil.ir 4
(DosinK Devic e)
Slurrv
Agilalcr lor Ferrir ^
Chloride
ftm.|i Icr PVi-nrk 4

(Jon Tank
Cam PI S\ steTn)
Cake Hopper ^
Tola] 37 unilf.

Elul nated

pa
P* .\
persons for ) un i 1 s

34. K m x 14 m) 487-2 m2


Nambu Se.agP 1

Vacuum Pi I 1 er

3.- m(W)
Hotal lonal 0. U 0. 1 rpm
Filter Cloih Pol v|.r(.|.v[ene
NumbeJ' 1 uni L.s
(Dewater,nK Equipment)
FiJ Irate Pumjj
The Other PumFj--- 8
Compressor 2
(Dosinfi Dp\ ire)
Slurrv

Chi., ride
Pump Cur Ferric 3

1 ion Tank
(Carrier System)
Cnnvever 10
Cake Hopper
Tuial 73 units

Elul nated

pa
Pa .
t persons r«.r 1 units

27.0 m X IT m) 405 m^





Fl.u Hale
Number 4 uni Is

(Dewalerjnn Equipment)
Coagulant Pped Pump 4
The 01 her Piimps 2
Agitalor
(Dosing Devire)
Coagulant Hopper
Coagulant Constant
Polymenc 1
Coagulant Constant
Feeder
(Carrier System)
C»n\«»pr 7
Cake Hopper 4
Tntal 32 units

Digested

I»
pa
! person for 4 units

(27.0 m x 11,0 m) 40S m2



Type Horizontal Type


Chamber (1 m(L) x
1 m(tf)>
Number b uni ts
(Devatering Equipment)
The Other Pumps 4
Compressor 4
Oil Pump Unit 3
Agitator 6
(Dosing Device)"
Slurry
Slurry
Pump for Ferric I unit
Chloride
(ion Tank
(Carrier System)
Con\e.ver 8
Cake Hopper 2
Total 43 units

{A*M Thi.kened

pa ,
pa
Oxidation) ing of Thickened
Sludge
6 units 6 units
(28 m x 13.6) 38O.8 m2



Type Vertical Type
Pressure Filter

Chamber (0-9 m(L) x
i.75 m(W)>
(to be 6)
iDevatenng Equipment)
The Other Pumps 8
Compressor 2
Oil Pump Unit 1 unit
(Dosing Device)
Slurry
Slurry
A«iLBtor for Ferric 2
Chloride
Chloride
(Carrier System)
Conveyer 5
Cake Hopper 4
Total 34 units

Thickened


pa y
2 persons for 2 units

(15 m x 25 m) 371 m*



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1.1.2 THE  REASON OF SELECTING THE  MACHINES
     a.  Chubu Sewage Treatment Plant
     Chubu Sewage Treatment Plant, the first treatment plant erected in Yokohama
City, has been in operation since 1962. In selecting the dewatering facilities, scraper-
discharge vacuum filters whose positive achievement was known then were adopted.
     Later, the machines were changed to BVFs in 1965 because the achievement of
the BVF with a larger treating capacity than the scraper-discharge vacuum filter was
known.
     b.  Nambu Sewage Treatment Plant
     BVFs were  installed as the dewatering machines of the Nambu Sewage Treat-
ment Plant in 1967 after the experience. in the Chubu Sewage Treatment Plant.
However,  as the ratio between the night  soil and  the sewage sludge decreased later,
the expected capacity could not be achieved and the  enlargement of the facilities
became  necessary. After many considerations, SDs with  improved  efficiency by
structural modifications  and the use of polymeric coagulant were adopted in 1973.
These machines fulfilled the requirements of limited  installation space and continu-
ous operation with infrequent inspection.
     c.  Hokubu Sewage Treatment Plant
     For  dewatering of the  sludge  after wet  air oxidation obtained in Hokubu
Sewage  Treatment plant, BVFs and HPFs were  compared and HPFs which yield
cakes with lower water content were installed in 1968.
     d.  Second Totsuka Sewage Treatment Plant
     PFs were selected as the  dewatering machines  of Totsuka Sewage Treatment
Plant, which was expected to yield cakes with lower water content so that the dis-
posal by land fill is easy and the disposal after incineration expected in the future is
advantageous.  VPFs with a greater filtration rate and a smaller installation space
than HPFs were installed and have been in operation since 1974.
1.1.3 MAINTENANCE
     a.  Characteristics of Maintenance
     Various  running  characteristics, problems and periodical inspections etc. are
shown in Table 1.2.
     b.  Main Modifications
     Various  modifications have  been carried out after our operating experience,
some examples of which will be described below.
     -BVF
     - To prevent clogging of  the filter cloth and to improve the efficiency of the
dewatering machines, automatic filter cloth washing machines which utilize water at
high pressure  (rapidly filtered water after secondary treatment) were  installed.
Washing is carried out  automatically  for  about  30  minutes after the dewatering
operation  is over by spraying water at high pressure  evenly over the filter cloth as
the washing nozzle reciprocates horizontally while the  drum rotates. As a result of
this modification, the dewatering operation could be prolonged by about an hour a
day.
                                    101

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                                                     Table 1.2  Characteristics of  Maintenance
o
t-o
^^^"Types of
^^ Machines
Items ^^^
Operating Characteristics
Details of the
Periodical
Inspection
Maintenance
£ *-
•J: M> p c
£ -S £ 1
* c c
D
BVF
(1) Because the dewatering is conducted by filtering by vacuum,
there is a limit to the water content of the sludge cake.
(2) Not suited for dilute sludge. Empirically, when TS concentra-
tion is less than 3%, the cake layer is not formed, the filter
cloth cloggs quickly, the cake barely comes off and hence
dewatering is impossible.
(3) If the disposal of the cake by land fill is planned or if con-
tinuously stable cake is needed, the feed sludge, with more
than 4% of TS is necessary. (Empirical rule)
(4) To maintain the filtering capacity, large amount of the filter
cloth and the washing water is necessary. The filter cloth
must be washed with acid for regeneration.
(5) Carbide slurry used as a dewatering adjutant adheres to the
vacuum tube in the drum as hard scales lowering the filtra-
tion rate and hence must be cleaned periodically
(6) The filter cloth tends to form wrinkling which influences the
filtration rate.
(7) Because the open area is large, some measure must be taken
to prevent odor.
[1) No legal obligation of inspection.
(2) Auxiliary devices such as a vacuum pump or a filtrate pump
are important in dewatering and require rigorous periodical
repair.
'3) Machines with sliding parts such as a cake discharge roller, a
high flow valve and a compressor must be periodically
inspected.
(4) The filter cloth must be washed with acid for regeneration.
(1) Duration of the filter cloth must be judged and the filter
cloth must be exchanged.
;2) Coming off of the cake, winding of the filter cloth etc. must
be inspected. If necessary the revolving rate of the drum and
the dosing rate must be controlled.
[3) There are many kinds of auxiliary devices such as a vacuum
pump, and their maintenance is indispensable for stable and
effective dewatering.
(1) While washing the filter cloth, the worker might inhale the
volatile component of acid.
(2) Dewatering of the thickened sludge causes bad odor.
PF
(1) Dewatering i< conducted by pressing and squeezing, and
hence the water content of the sludge cake can be low.
(Sludge cake with the lower water content can be obtained
than any other types of the machines.)
(2) Since the machine is operated batchwise, when the initial TS
concentration is higher, the filtration rate is greater and more
stable.
(3) Not suited for dilute sludge. Dewatering is not impossible but
the cycle time must be considerably prolonged, the dosing
rate must be extremely large, and the filtration rate is
expected to become very low.
(4) The cycle time can be controlled but it will not improve the
filtration rate to any great extent,
(5) To maintain the filtering efficiency, filter cloth washing
water at high pressure is necessary. The filter cloth must be
washed with acid for regeneration.
(6) If the dewatering process is carried out while the cake is
adhered to the frame of the filter cloth, it sometimes leaks
between the filter cloth and filter plate.
(1) No legal obligation of inspection.
(2) The filter plate m'oving mechanism must be periodically
repaired.
Adjustment and renewal of parts of the oil cylinder or the
opening and closing mechanism of the filter plate are
necessary.
(3) Machines with sliding parts must be periodically inspected.
(4) Same as BVF (4)
(1) Same as BVF (1)
(2) The wrinkling of the filter cloth, the leakage between the
filter doth and the filter plate, coming off of the cake and so
forth must be watched. Cycle time must be adjusted.
(3) Careful maintenance of the auxiliary devices is indispensable
foi stable and effective dewatering.
Same as BVF
SD
1) Dewatering mechanism is the forced consolidation and pre-
cipitation. Therefore, it is possible to dewater at a low con-
centration of TS. If one may ignore the recovery ratio of
solids to some extent, the machine may be operated without
dosing.
(2) If a proper coagulant is selected, the machine may be operat-
ed at a low dosing rate. The water content of the cake is
influenced by the amount of VTS.
(3) The feeding rate of dry solids is limited by the strength of the
gears. Hence, if the sludge is very thick, the flow rate must be
controlled.
(4) Properties of the sludge cake are not suited for disposal by
land fill. But the water content in the sludge cake is small in
comparison with BVFs. Stable production of the cake is not
limited by the concentration of the feed sludge in contrast
to other types of machines.
(5) Feed sludge rich in sand wears the screw rotor and the outer
drum quickly. Hence the sand must be fully removed.
(6) Rotation at high speed causes vibration and noise when the
machine is in operation.
(7) Because of the high-speed rotation, screw rotor, outer drum
and the outlet tend to wear quickly and must be periodically
repaired.
(8) The separated liquid foam readily sometimes making drainage
difficult.
(1) Periodical and voluntary inspection of a centrifuge with a
revolving part at high speed is imposed by the Safety and
Hygiene in Labor Act.
(2) Because of the high-speed rotation, planet gears and bearings
must be periodically inspected.
(3) Wear of the parts which slide or collide with the sludge such
as screw rotor and the outer drum must be repaired.
(1) The separated liquid, the state of the cake and driving force
of the rotor must watched. The dosing rate and the feeding
rate must be controlled.
(1) Noise and vibration during operation are large.

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     - To better the coming off of the cakes, flapper rollers were installed. By this
modification, TS concentration limit at which the coming off of the cakes becomes
bad was improved to 3% from 3.5%.
     -SD
     — Because the inner drum screw and solids discharge outlets wore out rapidly,
the padding material was changed to a wear-proof one. By this modification, the life
time was lengthened from 1,800 hours to over 3,000 hours. For this reason and for
having changed the rate  of  rotation from 3,400 rpm to 2,400 rpm, the machines
have already been operating continuously over 4,000 hours.
     -HPF
     — When slack filter cloth is introduced  into plate closing process, wrinkling of
the filter cloth arises which  results in breakage. To prevent this, a weight (a round
bar of vinyl chloride)  was placed at  the lower end of the filter cloth, by which
modification the wrinkling arose no more.

1.1.4 THE RESULTS OF  OPERATION
     The results of operation in respective treatment plants in 1975 are shown in
Tables 1.3 ^ 6. Because the SDs in Nambu Sewage Treatment Plant were modified,
the results after June, 1976 are shown (Table 1.4).
     In Table  1.7 operating states of respective dewatering machines are  compared.
The dewatering rates of aH of the dewatering machines were lower than was initially
expected partially in connection with the quality of the feed sludge.
     The difference between the standard operation and maintenance cost and the
actual one arose mainly due to  the difference in the number of  the operating
personnel.
    Fig. 1.12  Automatic  Filter  Cloth
              Washing Device by High-
              Pressure Water
Fig. 1.13  Cake Flapper Device
                         Nozzle Header
                         (Nozzle Flat Type, Spray Angle 20°)
                                                          Discharge Rollei
                                     103

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              Table 1.3  The  Results  of  Operation  at  Chubu  S.T.P.
                                                                                (BVF)
Month, Year
Apr., 1975
May,
Jim. ,
Jul. ,
Aug.,
Sept. ,
Oct.,
Nov.,
Dec. ,
Jan., 1976
Feb.,
Mar.,
Average
Feed Sludge
(Elutriated Sludge)
TS(%)
3.8
3.0
3.9
4.6
4.0
4.1
4.1
4.9
5.8
5.0
4.0
4.3
4.3
VTS(Z)
49
49
46
44
47
48
46
48
38
43
48
49
46
Dosing Rates (%)
Carbide
Slurry
32.9
50.8
54.0
42.3
44.2
47.3
40.9
34.1
27.9
31.2
44.0
37.1
40.6
Ferric
Chloride
5.9
10.5
11.0
8.2
8.2
8.3
7.9
6.9
5.1
6.4
8.9
7.9
7.9
Sludge Cake
IS (%)
22
21
22
24
25
22
23
26
24
24
24
23
23
»2
Filtration
Rate
CKe/mZ-h)
13.0
9.4
9.9
12.9
12.0
11.5
12.8
15.6
19.2
19.9
13.9
15.6
13.9
Average
Operating Time
(h/unit-day)
3.0
3.5
3.4
4.3
3.7
3.0
4.9
3.3
3.8
3.7
3.7
2.8
3.5
* 1   The dosing rates are the weight ratios of slaked lime and ferric chloride to the amount of solid in the sludge.
    (Same for all of the treatment plants.)
*2   The filtration rate is given on the basis of the amount of solids in sludge cake excluding the coagulant.
    ("Same for all of the treatment plants.)
*3   The average operating time is the total operating time divided by the number of machines operated.
    (Same for all of the treatment plants.)
               Table 1.4  The Results  of  Operation  at  Nambu S.T.P.
                                                                                 (BVF)
Month, Year
Jim., 1976
Jul.,
Aug.,
Sept. ,
Oct. ,
Nov. ,
Average
Feed Sludge
(Elutriated Sludge)
TS(Z)
3.4
3.8
-J.b
3.7
4.6
4.5
3.9
VTS(Z)
45
41
40
42
41
45
42
Dosing Rates(%)
Carbide
Slurry
39
33
26
28
25
24
29
Ferric
Chloride
7.8
6.7
6.4
6.6
5.2
5.5
6.4
Sludge Cake
TS «)
22
23
23
22
25
22
23
Filtration
Rate
(Kg/mZ-h)
10.0
8.8
8.2
10.4
11.5
9.8
9.8
Average
Operating Time
(h/unit.day)
6.0
5.7
6.3
5.8
5.6
3.4
5.5

Month, Year
Jun., 1976
Jul. ,
Aug. ,
Sept. ,
Oct. ,
Nov .
Average

Feed Sludge
(Digested Sludge)
TS(Z)
3.2
3.6
3.8
3.5
J .4
3.1
3.4
VTS(2)
44
43
43
43
44
47
44
(SD)
Dosing Ratea(Z)
Polymeric
Coaeulant
0.86
0.83
0.78
0.78
0.78
0.74
0.80
Sludge Cake
TS (I)
25
26
25
26
26
23
25
Feeding
Rate of *
Dry Solids
284
278
291
277
246
260
273
Average
Operating Time
(h/unit-day)
20.1
17.3
13.2
15.0
16.0
11.1
15.5
                                            104

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          Table 1.5  The Results  of Operation  at HokubuS.T.P.
                                                                      (HPF)
Month Day,
Year
May 2,
1975
Jul.25,
Jul . 31 ,
Oct. 22,
Oct. 23,
Mar . 5 ,
1976
Mar. 9,
Mar. 16,
Mar. 26,
Average
Feed Sludge
(Thickened Sludge)
TSU)
9.2
7.3
5.6
7.9
7.9
10.2
9.8
10.4

8.5
VTS(%)
38
36
36






37
Dosing Rates (%)
Carbide
Slurry
38
54
34
34
46
59
59
76
65
52
Ferric
Chloride
5.0
3.6
4.0
2.4
2.5
5.0
6.0
6.0
5.0
4.4
Sludge Cake
TS (%)
41
36
37
42
40
44
41
44
37
40
Filtration
Rate
(Kg/m2-h)
3.5
2.8
2.7
4.1
3.9
3.5
3.0
3.0
2.8
3.3
Average
Operating Time
(h/unit-day)
5.3
3.6

3.5

3.5



4.0
    Table 1.6  The  Results of  Operation at the  Second Totsuka  S.T.P.
                                                                     (VPF)
Month, Year
Apr., 1975
May,
Jun. ,
Jul.,
Aug. ,
Sept. ,
Oct. ,
Nov. ,
Dec. ,
Jan., 1976
Feb.,
Mar.,
Average
Feed Sludge
(Thickened Sludge)
TS(%)
6.0
6.2
7.3
7.3
5.6
5.0
7.9
5.8
4.5
3.0
3.5
4.6
5.5
VTS(%)
39
40
37
34
40
45
34
43
53
61
62
58
46
Dosing Rates
Carbide
Slurry
53
39
51
37
39
39
38
42
51
56
59
56
47
Ferric
Chloride
8.9
9.0
7.7
7.8
7.3
7.3
7.2
7.9
12.0
13.0
11.0
11.0
9.1
Sludge Cake
TS (%)
43
38
40
44
45
44
44
42
35
31
31
34
39
Filtration
Rate
(Kg/m2.h)
8.0
7.5
8.0
9.7
7.8
6.7
11.0
7.4
6.1
4.9
3.7
4.6
7.1
Average
Operating Time
(h/unit-day)
8.3*1
7.1
6.9
6.9
7.0
6.6
6.6
6.7
6.5
10. 6*2
15. 6*2
7.2
8.0
* 1   In April, 1975, the dewatering machines were operated for 10 hours a day.
*2   From Jan. 28 to Feb. 21, 1976, the machines were operated for 24 hours a day.
                                     105

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       Table 1.7  Comparison of Respective  Dewatering  Machines
^^Types~
Items

Feed Sludge
(annual averages)

Dosing Rates

Sludge Cake
(annual average)

(kg/mZ-h)
Actual Working Times
of
Dewatering Machines
(h/unit-day)
Oper tors
(per ons/unit)
Oper tion and
Main enance Costs
per on of Feed Dry
Solids (S/ton)
S.I. P.
-.JJachines
Kinds
TS(2)
VTS(%)
Carbide
SlurryU)
Ferric
Chloride(%)
TS«)
Rated
Actual
Actual
Standard
Actual
Standard
Actual
Standard
Chubu
BVF
Elutriated Sludge
$.1
48.0
40.6
7.9
23.0
25.0
13.9
3.5
3.0
1.3
0.8
170.14
148.61
Ms
BVF
Elutriated Sludge
3.9
42.0
29.0
6.8
23.0
25.0
9.8
5.5
5.6
0.8
0.8
138.42
138.59
»bu
SD
Digested Sludge
3.4
44.0
• Polymeric
Coagulant
0.8

25.0
The feeding rate of
Dry Solids
400 kg/hr
The feeding rate of
Dry Solids
273 kg/hr
15.5
19.2
0.25
0.2
104.73
104.04
Hokubu
HPF
Thickened Sludge
8.4
37.0
51.7
4.4
40.2
5.5
3.3
4.0
5.6
0.5
0.4
106.45
99.97
Second Totsuka
VPF
Thickened Sludge
5.5
45.5
46.6
9.1
39.2
15.0
7.1
8.0
5.6
1.0
0.4
133.39
119.01
 These are the estimated standard valui
 machines.
                     lues of the working hour and the operating personnel for respective


The standard cost was calculated on this basis
Table 1.8   Details  of  the  Standard Operation and  Maintenance  Cost per
             Ton  of  Feed  Dry Solids
^^iL
Details \
Coagulant
Cost
Personnel
Cose
Electric
Carriage
Cost
Disposal
Cost
Repair
Cost
Grand
Total
BVF
(Chubu)
Feed Dry Solids
6.33t/day
Number 3 units
Costs
Sums(S)
14. 14*1
19.97*:
12.84
3.87
L7.94
75.37
2.48
148.61
Percentage
(10)
(13)
23
9
2
13
51
2
100
BVF
(Nambu)
Feed Dry Solids
9. 30t/day
Number 5 units
Costs
Sums(S)
10.10
17.17
14.58
3.67
18.21
68.83
6.03
138.59
Percentage
(7)
(12)
19
11
3
13
50
4
100
SD
Feed Dry Solids
26. lit/day
Number 4 units
Costs
Sums(S)
"3
34.67
1.05
6.08
12.44
47.02
2.78
104.04
Percentage
33
1
6
12
45
2
100
HPF
Feed Dry Solids
9.23t/day
Number b units
Costs
Sums(S)
17.97
11.11
0.81
1.46
12.04
45.50
3.08
99.97
Percentage
(18)
(11)
29
9
1
12
46
3
100
VPF
Feed Dry Solids
1.99t/day
Number 2 units
Costs
Sums (5)
16.02
22.68
13.62
6.57
12.25
46.32
1.55
119.01
Percentage
(14)
(19)
33
11
6
10
39
1
100
 * 1 Carbide Slurry
                 '2 Ferric Chloride     *3 Polymeric Coagulant
                                         106

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1.1.5  OPERATION  AND MAINTENANCE COST
    Details of the standard operation and maintenance cost are shown in Table 1.8.
    a.   The BVF is the most expensive and the HPF the least expensive. This is
considered to be related to the fact that the feed sludge to the BVF (TS 4.3%, VTS
48%)  is the most difficult to dewater while the feed sludge to the HPF (TS  8.4%,
VTS 37%) is easy to dewater.
    b.   The cost of disposal occupies a large portion of the cost, between 39% and
51%, in all of the machines. Then follows the coagulant cost which is between 23%
and 33%. The fact indicates that, to lessen the dewatering cost, a machine with a
smaller  amount of cake produced,  i.e., with  lower water content of the sludge
cake, and a lower dosing rate should be selected.

1.2  THE RELATION  BETWEEN  THE FEED SLUDGE AND  THE
     DEWATERING  EFFICIENCY

    The major problem in dewatering treatment of the sludge is the fluctuation in
quantity and  quality of the feed sludge. The fluctuation in quantity can be coped
with by storage and proper selection of the operating hours.
    The fluctuation in quality of the  sludge causes the fluctuation in the  water
content of the  sludge cake resulting in poor  coming  off of the cake and extreme
diffuculty of the dewatering operation.
    Sludge treatment  facilities have hitherto been  designed by application of the
standard dosing rate and filtration rate expecting sludge of the standard quality.
Therefore, when the dewatering of the sludge becomes poor, the dosing rate must be
increased and the operating time  must be temporarily  prolonged. Such changes not
only cause problems in sludge treatment  and personnel management, but also induce
the suppression of the withdrawal of the sludge and the increase in the amount of
the circulating sludge, which  together cause serious  problems in the  quality of the
sewage treatment plant effluent.
    Therefore in design, operation management and evaluation of the dewatering
machines, it is important to know the  characteristics of the machines, such as the
quality of the product of the machines, the rate of production and the controlling
factors, in response to the fluctuation in  the quality of the feed sludge.
    The dewatering  process has a three dimensional  structure  with variables, the
quality of the feed sludge (x), water content of the sludge cake (y)  and the dewater-
ing rate (z) and the controlling factor (p) as the parameter. However, it is not easy to
solve it. Therefore, as an approximation  for practical purposes, the relations, y=f(x),
z=f(x)  and  p=f(x) with the  assumptions that x is  a  given variable  and that two
excluded variables are  within appropriate ranges, provide enough information to
decide how to cope with the situation in the plant and to  reveal the  characteristics
of the dewatering machines.
    Among many factors which  may be taken to represent x,y,z and p, our operat-
ing experience up to now suggests to select VTS for x, dosing rate for p,  water
content of the sludge cake for y and the filtration rate on the basis  of the treated
solid for z. Taking such factors as the variables, the aforementioned relations will be
as follows.

                                     107

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1.2.1  TS AND VTS
    TS of the feed sludge  has hitherto been counted among the factors which
determine the dewatering efficiency of the dewatering machines including the filtra-
tion rate. It is also our experience that the dewatering efficiency changes depending
upon  the TS.  But when we encounter seasonal difficulty in dewatering of the
sludges, TS decreases but at the same  time  VTS  increases. The phenomenon is
thought to arise from the facts that the feed sludge has been thickened and separat-
ed in  a so-called gravity thickener and that the components of VTS are inhibitory
factors of thickening with high viscosity and strong affinity to water. Therefore, as a
parameter to represent the properties of the sludge VTS is preferred.
    The relation between TS and VTS is shown in Fig. 1.14.
    The seasonal fluctuation in the amount of VTS is shown in Fig. 1.15.
    The amount of VTS  fluctuates  seasonally in any of the municipal treatment
plants. When the VTS level is high, dewatering is difficult. Also, the longer the plant
has been in operation, the higher the VTS level is.

1.2.2   DEWATERING  RATE AND  VTS
     The relation between the filtration rate and VTS in the BVF and the VPF is
shown in Fig. 1.16. The straight line in the figure is a regression line.
     In the information  obtained from the BVF, the range  of the VTS level of the
elutriated sludge is narrow and scattering is large. Therefore, the correlation between
VTS and the filtration rate is more marked in the VPF than in the BVF.
     Some of the characteristics of the machines found in this figure are as follows.
     a.  Because BVFs are run continuously, the filtration rate of the BVF is greater
than that of the VPF, but the VTS level of the feed sludge seems to influence the
performance of BVFs to a greater extent than VPFs.  It has been experienced that, at
a higher level of VTS, the cake layer becomes thinner, comes off the filter cloth less
readily and, along with the clogging of the filter cloth, makes it unfeasible to filter.
     b.  VPFs are run batchwise in a  cycle comprising filtration, squeezing and cake
discharge because of its  mechanism. Therefore, the  filtration rate is lower than that
of the BVF but VTS influences to a smaller extent than the BVF.
     c.  In contrast to BVFs and PFs, SDs dewater by forced consolidation with the
centrifugal force.  Therefore, to  express its  capacity, feeding rate  of dry solids
(flow rate  X TS) is used. If the flow rate more than the rated capacity is supplied
when TS is low,  the holding time shortens and hence the recovery ratio becomes
bad. In practice, the feeding rate of dry solids is about 80% of the rated capacity.
1.2.3   DOSING  RATE  AND VTS
    In Figs. 1.17, 18  is shown the fluctuation in the dosing rate of ferric chloride
and carbide slurry depending upon VTS  during dewatering  of the elutriated sludge
by the BVF.
    In Figs.  1.19, 20  is  shown  a  similar  fluctuation during dewatering of the
thickened sludge by the VPF.
    In Fig. 1.21 is shown a  fluctuation in the dosing rate of the polymeric coagu-
lant depending upon VTS during dewatering by the SD.
                                     108

-------
    The present method of dosing control is instrumentally a proportional adding
method to  the feed dry solids, but in practice the operator determines the appro-
priate level by observations of the cake coming off the  filter cloth during actual
operation. Hence, the scattering in the dosing rate is large, but it may be assumed
that the  change in the dosing rate depending upon VTS during dewatering of the
thickened sludge by the VPF is considerable.
    In the case of the elutriated sludge, the correlation is small on the same reason
as the  aforementioned filtration rate. The dosing rate for  the elutriated sludge is
supposed to be smaller than the thickened sludge. The dosing rate of the polymeric
coagulant used in SDs is also influenced by VTS.
1.2.4  WATER  CONTENT AND  VTS
    In Figs. 1.22, 23 are shown relations between the water content of the sludge
cake and VTS for respective dewatering machines.
    Water  content of the sludge cake is also  influenced by VTS. Water content of
the cake is the highest in the BVF. The  performance of the SD is most drastically
influenced by VTS, and at a higher level of VTS, the water content of the cake is
about the same as that of the BVF.
                                     109

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Fig.  1.14    TS  vs.  VTS
                                            Fig.  1.15    Seasonal  Fluctuation  of  VTS  of  Thickened  Sludge
•A  blulmlnJ Sludge I Ha ml
0  Digc^cJ SluJpt INjmhi
0  DiiteileJ Sludge iChuhu
                                     I. 40
                                                                                                       o.	  Chubu (Started in 1962)
                                                                                                       A.	  Nambu (Started in 1965)
                                                                                                       0.	  Hokubu (Started in 1968)
                                                                                                       O,	  Second Totsuka  (Started in 1973)
                                             Oct.  Nov. Dec. Jan.  Feb. Mar.  Apr  May  Jun.  Jul.  Aug. Sept. Oct. Nov. Dec. Jan.  Feb. Mar. Apr.

                                                        T975                                             1976
                                                                             Month, Year

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         Fig. 1.16   Filtration  Rate vs.  VTS
Fig. 1.17  Dosing  Rate  (Ferric  Chloride) vs. VTS
           JO        40        50        60       70
                                                                                                 (Elulniled Shidtt.Oiubu)
                                                                      30        40
                                                                                        SO        60
Fig. 1.18   Dosing Rate (Carbide Slurry) vs. VTS       Fig. 1.19   Dosing Rate (Ferric Chloride)  vs.  VTS
                                                                                                     fThu-kerwJ Smdfr
                                                                                                     ndTolwkal    J
                                                                      30        40        SO        60

                                                                                  VTS(It
                                                     111

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Fig. 1.20   Dosing Rate (Carbide Slurry) vs. VTS     Fig. 1.21   Dosing Rate (Polymeric  Coagulant) vs. VTS
                                  _J	L
    Fig. 1.22   Cake Water Content vs.  VTS
Fig. 1.23   Cake  Water  Content vs. VTS
                           o 	  BVF (Eluirmed Sludic.
                           O	VPF (Thickerwd Slud»c
                          	Second Toltukal
                                                     £ 60
                                                     e
                                                                          40       SO
                                                 112

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1.3  EVALUATION OF THE  DEWATERING MACHINES
    In preceding sections the present state of the mechanical sludge-dewatering in
Yokohama City  and characteristics of various dewatering facilities and dewatering
processes have been explained. In the following we attempt to evaluate dewatering
machines on the basis of those informations.
1.3.1  THE  RANGE OF COMPARISON
    Dewatering efficiency, sludge management cost and the like were calculated for
each of the  cases listed in Table 1.9 for respective dewatering machines for com-
parison.

              Table 1.9 Conditions for Comparison of the Dewatering Machines
Dewatering Machines
Types
BVF
VPF
HPF
SD
Working Time
(hours)
7
24
Capacity
Of Maximum Capacity
Possible Now
Feed Sludge
Kinds
Thickened
Sludge
VTS (Z)
35
47
60
Dry Solids
(t/day)
10
20
30
40
50
           *  VTS at 35% was the average concentration when the operation was started.
              VTS at 47% was the annual average concentration in 1975.
              VTS at 60% was the average concentration during winter in 1975 - 6.

     Although not all of these cases are feasible, but  the factors were calculated to
 know the main trend.

 1.3.2  THE METHOD OF DETERMINING THE  CAPACITY OF THE
       DEWATERING MACHINES
     For evaluation it is important to know how the capacity of various dewatering
 machines changes depending upon the fluctuation of various conditions.
     Here the linear  functions obtained  from  the information in Section  1.2 in
 which  the various properties of the machines including the dewatering capacity were
 studied are used. These functions are shown in Table 1.10.
     The accuracy of these functions has to be determined by further research and
 analysis,  but the main trends are to a large  extent  in agreement with the  actual
 experience. As to the filtration rate and the water content of the cake for BVFs, the
 actual  result of treating the elutriated sludge was used, and as to the dosing rate the
 actual  result by VPFs was used.
     The results in Table  1.10 are shown schematically in Figs. 1.24 'v 28.
     In Fig. 1.24, the capacity of the HPF was calculated by assuming the cycle time
 of 30 minutes while that of the VPF is 20 minutes.
     Other assumptions are listed in the bottom column of the Table of Comparison
 (cf. Table 1.11).
                                     113

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Table 1.10   Characteristics of  the Capacity of Respective Dewatering  Machines
             (The  Results of Operation  Depending Upon  VTS)
                                                                        X = VTS
"- 	 ^Types of
^~~"-~-~L^Ma ch i ne s
Items ^^"--^^^
Dewatering Rate
(Kg/m2.h)

s~\
B^
CO
0)
4-1
<3
60
c
•rl
01
&
B~!
01 r*.
M^a-
•o .
3 HI
H >


o> o
11 £
Jd S
O ro
•H en
jn H
H >
cu
T) t^
•H >->
J= M
VJ 3
M ,H
O CO

HI
•rl -H
1-1 H
H O
01 r-l
^g
Cake Water Content
(%)

BVF

33.06-0.415X
Y=0.409**(«S=50)

Same as Right



Same as Right

68.3+0.181X
Y=0.286*(«(=50)

VPF

15.3-0.187X
Y=-0.802**(«i=71)

20.2+0.583X
Y=0.567**(«S=71)



1.0+0.188X
Y=0.667**(«i=71)

38.9+0.455X
Y=0.671**(«!=71)

SD

1200*1(Kg/h)

.Polymeric.
^Coagulant

-0.5+0.034X
Y=0.528**(<4=60)
(30 ^ X <; 50)

37.1+0.844X
Y=0.687**(^=45)
  *   Significant at P < 0.05
 **   Significant at P< 0.01

 *1   The rated  capacity of the SD is assumed 50 m3/h provided TS is 3%. The dewatering rate is
     assumed 80% of the rated rate after the past performance in city's treatment plants.


                        Fig. 1.24   Filtration  Rate vs.  VTS
                E 15
               -a
o 	 o BVF
0 	 0 VPF
D— 0 HPF
Full line indicates the rang
actual results



cof
                                     30     40     50     60
                                       VTS (%)
                                       114

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Fig. 1-26   Doting Ran (Cwtahto Slurry)  m. VT8
        I0  10  30  40   50   60   70
                   VTS (%)
                                                                                Fig. 1.26  Doting Rat* (Farrtc Chtoridt) w. VT8
                                                                                                                FuU line Indldlet the
10   :0  30   40  SO   60   70
          VTS (%)
  Fig. 1.27   Dosing  Rate (Polymeric Coagulant) w. VTS
         10   20  JO  40  50  60   70

                   VTS (%}
                                                                                   Fig. 1.28  Cake Watar Content«. VTS
  10   20  .'0  40  ^0   60   70
             VTS I'll
                                                           115

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                 Table 1.11    Economic Comparison  of  Respective Dewatering  Facilities  (Thickened  Sludge, VTS  47%)
O\
                          =J_»__j_r!
                          '•"  I ""


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  Fig. 1.29  The Amount and the Composition of the Sludge Cake Produced
            (Thickened Sludge)  Depending  Upon  VTS
   <3
   & 40
                                                90

                    (The Amount of the Feed Dry Solids lot/day)

                          80 r                   80
          BVF SD  PF
                               BVF SD  PF
I   I Water Content

I'.'-.-'.v.'l Coagulant

fe%3 Dry Solids
1.3.3  EVALUATION
    An example of the results of calculation within the aforementioned range and
conditions is shown in Table 1.11 (thickened sludge, VTS 47%).
    a.  The amount and the composition of the sludge cake produced
    The amount and the composition of the sludge cake produced by the dewater-
ing process have much influence upon the method and cost of the succeeding treat-
ment and disposal of the sludge. An example of the change in the amount and the
composition of the sludge cake produced is shown in Fig. 1.29 (thickened sludge).
    — The amount  of the cake produced is determined by the water content of the
cake and the amount of the coagulant used. The water content of the cake is higher
at a higher level of VTS, and its influence is most evident in SDs (cf. Fig. 1.28).
    — BVFs produce the largest  amount of the cake. This is mainly because of the
high water content of the cake, and, in comparison with SDs, is due  to the greater
amount of the coagulant used.
    — PFs can maintain a low level of water content and hence produce less cake.
    — SDs require lower dosing rate, and hence produce nearly the same amount of
cake as PFs when VTS is not high.
                                    117

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     b.  Sludge management cost
     The change in the dewatering cost per ton of the feed dry solids is shown in
Fig.  1.30. The  treatment cost was averaged  over various amounts of the feed dry
solids for each machine.
     An example of the details of the sludge management cost is shown in Fig. 1.31
(thickened sludge, annual sludge management cost at a rate of 50 tons per day).
     — The cost increases rapidly as VTS increases.
     - The BVF is the most expensive.
     - The SD is the least expensive when VTS is not very high.
     - The cost of the HPF is relatively low mainly because  the water content of
the cake is  low in comparison  with the BVF and the capacity of the machine is large
in comparison with the VPF.
     - As to the detail of the cost, the disposal cost is the largest and the coagulant
cost follows it.
     — It is characteristic to  large cities in Japan that  the disposal cost occupies a
large portion of the total cost. Hence,  if we exclude  it  from the total cost, the cost
of the BVF and the SD is smaller  than  that of the PF. However, the cost of drying
and  incineration is greater  than the disposal cost. Therefore the machines which
produce cakes with low water content are advantageous.
     - As to the fixed cost other  than  the disposal cost and the coagulant cost, the
SD is the cheapest.
     — The depreciation cost  of the  SD is the smallest. This is because SDs require
small number of auxiliary devices and hence the building cost is small.
     - There are many kinds of polymeric coagulants used for the SD. The function
for the  dosing  rate used for  the present analysis holds for only  one kind of the
coagulant, and the dosing rate is assumed to increase in proportion to VTS. There-
fore, if other appropriate  coagulants  are used when  VTS is high, the cost may
become considerably low.

      Fig. 1.30  Sludge Management  Cost per  Ton of Feed Dry Solids
                (Thickened  Sludge) Depending  Upon VTS
                           30    40    50    60    70

                                  VTS (*)
                                    118

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    Fig. 1.31   Annual Sludge Management Cost Depending Upon VTS
•s
o
    3.0 -
    2.5 -
    2.0  -
    1.5   -
   1.0  -
   0.5  -
                   3.22
                            (Thickened Sludge,  The Amount of the Feed  Dry Solids 50t/day)
              2.44
          1.97
                                   2.91
                                                   2.89
                                                                  2.70
          35   47  60
             VTS (%)
              BVF
35  47
  VTS (

    SD
60
35  47   60
  VTS (%)

   VPF
35  47   60
  VTS (%)

   HPF
                                      119

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      Fig. 1.32  Area of Installation  for  Respective Dewatering Machines
                Depending  Upon  VTS
     4,000
     3,500
     3,000
                                                                    5.500
                                                                    5,000
           10  20  30  40 50
                                 10  20  30  40  50

                          The Amount of the Feed Dry Solids (t/day)
                                                       10  20 30  40  50
     c.  The area of the installation
     In  Japan the land available for the treatment plant is generally limited due to
the shortage of land. The space for installation is also a big problem in modification
and  expansion of the sludge treatment facilities.  Therefore, in Fig. 1.32 are shown
areas of installation per daily feeding rate for respective dewatering machines.
     — The area of installation is generally large for machines which require aux-
iliary devices. The area is large in the order of
                 a PF,   a BVF  and   an SD.
There is little difference  between a VPF and  an HPF because an HPF has a large
capacity per a machine than a VPF.
     — The performance of the SD is not influenced by VTS because of its mecha-
nism of dewatering. The number of the  machine  required is determined by the
feeding rate.
     - In the PF and the BVF, the increase in VTS brings about the decrease  in the
filtration rate  and the increase in the dosing rate. Therefore, an increase in VTS as
well as in the feeding rate brings about a rapid increase in the area of installation.
     d.  Maintenance
     The characteristics  and problems in operation and  maintenance are listed in
Table 1.2.  Though  it  is difficult to evaluate, some of the points that  may be men-
tioned are as follows.
                                      120

-------
     — The operation of the dewatering process is superior in the order of
                anSD,   aPF     and   a BVF
taking continuous automatic operation as the standard.
     — As to the treatment process of the sludge cake (drying and incineration), the
machines are advantageous in the order of
                aPF,    anSD   and   a BVF
from the view point of the water content of the cake.
     — Disposal of the sludge cake (land fill) is easy in the order of
                a PF,    a BVF   and   an SD
because  of the properties of the sludge.
     e.  Some comments on the evaluation
     Evaluation of various dewatering machines has been attempted on the basis of
the operating experience. Some points which should be kept in mind will be listed.
     — The data for determination of the capacity of the dewatering machines were
obtained by analysis of the actual operation, and hence do not necessarily reflect the
true causal relation. Therefore, some of the actual values may change drastically by
further research and analysis.
     — As to the  annual sludge management cost, because  both the quality and the
.quantity of the sludge fluctuate, the cost should be integrated for each dewatering
machine according to this fluctuation to know the cost  for respective treatment
plants.
     —  The sludge  management cost is largely influenced by such factors as  the
length of the operating time or the capacity of a machine rather than the type of the
machines. Therefore, the  estimation of the amount of the sludge produced, determi-
nation  of the  facilities  and  the building program based  upon the estimate  are
important as well as the selection of the machine.
     —  It is expected that the  dewatering efficiency of the same type of machine
may be different depending upon the total sludge treatment system in which  the
machine is incorporated.
     The ultimate step of the evaluation of the dewatering machine is the choice of
the dewatering machine.  For this purpose, it  must be first determined into what
kind of sludge treatment and  disposal system the dewatering process should  be
incorporated. The dewatering machine which  is most effective and minimizes the
total cost within the system must be selected.  For such a selection, analysis of pro-
cesses other than dewatering  is necessary, which will be considered  elsewhere.
                                     121

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                              CHAPTER 2
        SLUDGE CONDITIONING BY USING HYDROGEN PEROXIDE
2.1  Introduction	123
2.2  Fundamental Study	123
    2.2.1   Leafiest	123
    2.2.2   Pilot Plant Test	126
2.3  Results of Batch Test in Full-Scale Plant	128
2.4  Results of Continuous Operation at the Full-Scale Plant 	130
2.5  Comparison with Traditional Processing  	131
    2.5.1   Physico-Chemical  Characteristics of the Dewatered Sludge
           Cake and Filtrate	131
    2.5.2   Disinfectant Action of Hydrogen Peroxide	132
    2.5.3   Working Environment	133
    2.5.4   Economics	134
2.6  Conclusion	135
                                  122

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2.1   INTRODUCTION
     The area of sewerage-service region (sewered area) in Osaka City has been
increased to 161.80km2 as of Dec. 20, 1976, meaning that the ratio of the sewered
area to urban area has attained a figure of 88%.
     All  12 sewage treatment plants planned to be constructed are in operation,
though  some of  them  are  being operated by  sedimentation  process, and they
treated sewage at an  average rate of 2,315,000m3/day in the year between April
1975 and March  1976 to produce dewatered  cake of about 500 tons per day.
     In Osaka City, the  area of which is narrow and mostly urbanized, a site for
sludge disposal is difficult to secure,  so that the treatment and the ultimate disposal
of sludge is a very serious problem in sewerage works. Fortunately the problem is
being solved  for the time being by  using sludge for  sea-reclamation works in the
north port establishing service in Osaka Bay, but these reclamation works will be
finished in 1985 according to the present schedule and after 1985 it is considered
impossible to secure a new disposal site in Osaka City.
     So far, some sewage sludge, incinerated after mechanical dewatering process by
using such  coagulants as ferric chloride, ferrous sulfate and slaked lime, has been dis-
posed to the above-mentioned sea-reclamation area in Osaka Bay. In this dewatering
process, the dosage of so much slaked lime (20 to 50% to dry solid in weight) pro-
vides consequently sludge cake in large quantity.  Moreover, when the sludge cake is
incinerated to reduce  its  quantity, it would not provide function of self-combustion
as the quantity of inorganic substances is relatively  large, and it requires not only a
large quantity of supplementary fuel but also incineration produces a great amount
of ash. Thus the purpose of the incineration  can not be completely achieved.
     To solve this problem, the sludge conditioning process using hydrogen peroxide
was developed through the discovery of the following mechanism;. Organic substances
in sludge are oxidized like a  chain reaction by the strong oxidizing action of the
hydroxyl radical generated from hydrogen peroxide in the presence of ferric ion and
also  their gel structures are destroyed to isolate water in an accelerated manner, while
ferrous ion turns into ferricion with a high coagulation effect which coagulate sludge
particles to form floes.
     Thus dewatering of  sewage  sludge can be accelelated by two actions, oxidation
and coagulation.

2.2  FUNDAMENTAL STUDY
     After  the effects of a  dosage  of chemicals and stirring on the  dewatering
characteristic of raw and digested sludges were studied by leaf test in the laboratory,
the operating condition to get design criteria was researched using a pilot-scale plant
of vacuum filter.
2.2.1  LEAF TEST
     Mixing Tank:        Diameter 15cm x Depth 20cm
     Mixing Equipment:   Diameter 10cm
                         Mixing velocity        0 to 1,200 rpm
                         Fan turbine impeller   (6-blades)
                                     123

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      Leaf Tester:           Area of filtering surface 19.6cm2
                             Degree of vacuum       SOOmmHg
                             Filter cloth   Shikishima canvas N74
      Both raw and digested sludge collected from the Tsumori treatment plant were

studied by using the above-described apparatus as follows.

      a. Dosage of chemicals
        A sludge  sample of 2 liters was collected in the mixing tank, ferrous sulfate
        and hydrogen peroxide were added in varied quantities, and the mixture was
        stirred for 10 minutes at  the stirring velocity of 200 to  300 rpm.  Then the
        leaf test  was  performed to measure  the  rate of filtration, the  water content

        of the cake, and the releasability.
        The  relationship  between the  filtration rate and the  dosage of hydrogen
        peroxide at  a definite dosage of ferrous sulfate is shown in Fig. 2-1 and in
        Fig.  2-2.  And the relationship  between the filtration rate and the dosage of
        ferrous sulfate at  a definite dosage of hydrogen peroxide is shown in Fig. 2-3

        and in Fig. 2-4.
                                                Fig. 2-2  Relationship between Filtration Rate
    Fig. 2-1 Relationship between Filtration rate
           and Dosage of Hydrogen Peroxide
     — 20-
       515-
       10-
  Tested Sludge:   Digested and
               elutriated Sludge
  Sludge
  Concentration:   6.3%
  Dosage of FeSO4 ' 9000mg/' Constant
   	(14.3%)
           750  1500  2250 3000 3750 (ppm)
           1.2   2.4  3.6   4.8
           ^ Dosage of H2 Oi (to Dry Sol id %)
     Fig. 2-3
       20
    Relationship between Filtration Rate
    and Dosage of Ferrous Sulfate
      o 15
        10
    Tested Sludge.       Digested and

                    Elutriated Skidge

    Sludge Concentration: 6.3%

    Dosage of H2 O2:     1,500mg// constant
I	 ___^	
 4500 6000 7500  9000 10500 12000 (ppml

~Ti£U5TTg  iTs  16.6 19.0
   —=- Dosage of FeSCM (to Dry Solid %)
                                                 25H
                                                E
                                                •a
                                                 •20-
                                                  10-
                                                    1
                                                       and Dosage of Hydrogen Peroxide
         Tested Sludge.       Raw Sludge
         Sludge Concentration:  5.37%
         Dosage of FeSO4:     5000 mg/1  Constant
      600  1000 1400  1800  2200 2600 3000(ppm)
     	l	1	1	1	1	1	r—l	1	1	1	1	1—
      1.1   1.9   2.6   3.4  4.1   4.8   5.6
       	 Dosage of HjOs (to Dry Solid %)

Fig. 2-4 Relationship between Filtration Rate
       and Dosage of Ferrous Sulfate
   13-1
                                        12-



                                      w

                                       OT
                                      It

                                      "jB 10-
                                                                 FeSO4-H2O2 Equimole
           Tested Sludge:      Raw Sludge
           Sludge Concentration:3.58%

           Dosage of H202:    1,500mg// constant
                                                       1500 3000  4500  6000 7500
                                                        4.2
                                                             8.4  12.6  16.8  21.0
                                                            Dosage of FeS04 (to Dry Solid %)
                                               124

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  From Fig. 2-1, 2, 3 and 4, the filtration rate indicates approximately its maxi-
  mum value near the equimolecular value of ferrous sulfate to hydrogen pero-
  xide.  Then  the  relationship between the filtration  rate and  the dosage of
  chemicals at  a definite mole  ratio of ferrous sulfate to hydrogen peroxide is
  shown in Fig. 2-5.
                        Fig. 2-5
                               Relationship between Filtration Rate and
                               Dosage of Chemical at a constant mole ratio
                         I 23-
                                  Tesled Sludge.      Digested and
                                               Elutriated Sludge
                                  Sludge Concentration  7 3%
                                  Mole ratio of FeS04 to
                                  H20a.          0745
                              6000   7500   9000
                                              10500lppm|
                                    2250   2700  3150lppml
                                    —:*. Dosage of H2O2
   From the above results it has become obvious that this process can be used
   for dewatering if ferrous sulfate of  10 to  15%  to dry  solid in  weight is
   added  and  hydrogen peroxide  of 1,500 to  2,500 ppm to  sludge slurry in
   volume is added for raw sludge  or for digested sludge, and that the dewater-
   ing process can be further improved in the region of the mole ratio of 0.6 to
   1.2 of ferrous sulfate to hydrogen peroxide.
b. Flocculating condition
   After a sludge sample of 2 liters was poured into the mixing  tank and hydro-
   gen peroxide at isoo mg/i and ferrous sulfate of 6000  mg/i were added, the ef-
   fects  of the  mixing velocity  and  mixing time on  the fitration rate were
   studied.
   The relationship between the filtration rate and the stirring time at a stirring
   velocity of 100 to 300 rpm  is shown in Fig. 2-6 and that at  the mixing velo-
   city of 300 to 900 rpm is shown in Fig. 2-7.
Fig. 2-6  Effect of Stirring Velocity and Stirring
       time on Filtration ratt.
                         10-Orpm
                         200rpm
                         300rpm

          flaw Sludge Concentration: 3.6%
          Dosage olHjOj. LSOOmg//
          Dosage ot FeSO: B.OOOmg//
                    (16.79H
                                                Fifl.
           5  10  IS 20 25  30
           	*• Stirring time (min.t
                                                  I. 2-7  Effect of Mixing Velocity on
                                                       Filtration rate
                                                 0—•© Mixing time of H202:10rr
                                                 0—0 Mixing time of H202:30min.
                                                 A—-&. Mixing time of Lime : 10 mm.
                                                 A—-A Mixing time of Lime 30min.
                                                 300    500    700   900
                                                  	a. Mixing Velocity {rpm)
                                        125

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       According  to the above results, the mixing tank should be designed to mix
       its contents homogeneously in as short a time as possible, while the floccula-
       tion tank should be  designed  to provide  as slow  a  velocity as possible in
       order not to give  excess  shear stress.  As the  sewage sludge  is a Bingham
       fluid, of which the yield point becomes higher with higher concentration,the
       sludge can not be mixed  homogeneously without a considerably high rota-
       tion when the diameter of an impeller to that of the tank  is small, but the
       shear stress is consequently  increased to destroy  floes at high rotation.
       Therefore slow rotation and a large  ratio of the diameter of the impeller
       compared to that of the tank are advantageous for a flocculation tank.

2.2.2  PI LOT PLANT TEST
     A dewatering  test was carried out by using the apparatus shown in Fig. 2-8 to
 confirm  the leaf test results under nearly the same conditions as at an actual plant,
 and by using a sample of raw sludge  mixed with digested  sludge from the Tsumori
 treatment plant. The effects of added chemicals, sludge concentration, the vacuum
 filter  operating condition, and  sludge flocculation  on  the filtration rate  were
 examined in checking its stability as regards continuous operation.
            Fig. 2-8
Outline of Pilot Plant
                                        l Mixing tank
                                 If
                                 COjCNj.
                                      TBcm
                                      . 20cm
                                                       Flocculation
                                                       tank
                                                           Belt Type Vaccum Filter
                                                           Effective Filtering
                                                           Surface:    0.54m2
          Sludge holding FeSO4   H202
             tank 500^   Solution Solution
                       tank    tank
                                       126

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    From those results shown in Fig. 2-9 to Fig. 2-14,  the following was confirmed.
Fig. 2-9 Relationship between Filtration Rate and
       Dosage of Hydrogen Peroxide
  25-
.c
c«


0)
ro
c20
_o
ro
U_

 1
  15
              /68.5%
             / 3.0mm
                               67.3%
                               3.0mm
     Drum Rotation
•—• 115 sec/cycle Velocity
a—0 200 sec/cycle
                 FeSO4/HjO2 =1 (mole ratio)

                  Sludge Concentration:  6.3%
                  Dosage of FeSO* :  8,500mg//
                                  ,,
                     2000         ' 2500
               Dosage of HjOj Img/ S )
                                        Fig. 2-10  Relationship between Filtraton
                                                 rate and Sludge Concentration

                                          28
                                                              -16-
                                                              c
                                                              o  _
                                                                              Drum Rotation Velocity
                                                                               •—• 90 sec/cycle
                                                                               O—-o 200 sec/cycle
                                                                            3     4     5    6
                                                                           • Sludge Concentration  1%)
   Fig. 2-11   Relationship between Filtration
             Rate and Drum Rotation Velocity
             or Submerged Filter Surface Ratio
                                       Fig. 2-12     Effect of Stirring Velocity on
                                                    Filtration Rate

50-

_ -
«
I30'
^20-
«;
|
I 10-
ii
1 :
1 5-
*~ Ratio 0.34 _
O— — O Submerged Filter Surface £
Ratio 0.24 1 20-
•a -
Ox ? -
\jr>^ s
^s»v I -
^>-N £ 15-
XXv =

\


JV
<*— — o^^^~~^"^~^
^^^^^^
^-^"^^-o

o—o Paddle Type Impeller 050cm
&~ ^ 3-bladed Propeller 032cm


100 200 . 300
Peripheral Velocity (cm/sec.)
1 1 ' l ' ' ' ' l
1 235 10
	 ~^ Drum Rotation Velocity (min./cycle)
Fig. 2-14 Performance on Continuous Operation
Test
Fig. 2-13 Relationship between Filtration Rate I7'0
and Stirring Velocity or Stirring Time |j> |
of Floccutator ^ S 6-°
^30-
|E -
528-
Q)
(0
-26
.2
fD
± 24-
122-

|

S £
(0 u
(J
^ 80
° 	 ^ ^S
'^-- §"70
	 O ^ '^
A 1 "
O—o Stirring Velocity 10 rpm 5 o 60
A~A Stirring Velocity 40 rpm v —
(0 "C
a: » 21-
c — .
0
-------
     *  The results at this pilot plant are in close agreement with those of the leaf
        test.  That is, sludge should be  mixed homogenously in as short a time as
        possible in a mixing  tank, while in the flocculation tank which should be
        used  like a storage tank, sludge should be agitated as slowly as possible, an
        absence of  sediment  and  an  impeller  having  a  large  diameter being
        advantageous.
     *  Even the dilute slurry of sludge about 2.5% can be stably dewatered without
        clogging the filter cloth so that this pilot plant can be actually used.

2.3  RESULTS OF BATCH TEST IN FULL-SCALE PLANT
     As the possibility of dewatering of sludge conditioned by this new process was
confirmed from the results of the leaf test and the pilot scale plant test, the full-scale
plant test was  carried out at the Nakahama sewage treatment  plant.
     One of  the three mixing  devices, which has been  previously installed, was
modified for  purpose of this test. The flow-sheet and the specification breakdown
of this equipment are given in  Fig. 2-15  and in Table 2-1 respectively.
     As a sludge treatment system combined  by digestion-elutriation-chemical con-
ditioning-dewatering processes  in series  was being used  at  this treatment  plant,
elutriated sludge after digestion mainly was tested.
     However, raw sludge  was also tested to some extent taking into account of the
future movement  to direct incineration of raw sludge without using digestion pro-
cess.
                Fig. 2-15 Flow-Sheet of Full-scale Plant
                                   Flow meter
            Digested Sludge
                     Dilute pump    Feed tank Feedpump
                                     128

-------
Table 2-1  Outline of Equipment
Name

1-,
£
:3
bu
-a
a
^
C
CO
H
c
.0
.*_>
«
*3
60
Ifl
0
O

Tested
Sludge
Ferrous
Sulfate



>
H-l
>!H



Mixing Tank

Mixer

Flocculation Tank


Flocculator


Filter

Feed Pump

Feed Tank
Feed Pump

Storage Tank

Dilute Tank

Feed Tank



Dilute pump


Feed Pump


Specification
Diameter 1 .3m x Height 1 .5m x max.
capacity 1.7m3 Stainless steel 304
Pitched paddle type
width 0.65m x 20 ~ 85 rpm x 2.2kW
Width 1 .5m x Length 3.3m x Height
1 .9m x max. capacity 7m3 Steel
Inner surface coated with epoxy resin
Pitched paddle type
width 1 .Om x 10 ~ 40 rpm x 3-steps
impeller 0.75kw
Belt type vacuum filter
Filtering surface area 33m2
Diameter 100mm x Head 13m x capacity
Im3/min. x 15kw
Width 2m x Length 8m x Depth 1.5m
Diameter 50mm x Head 13m capacity
50 Z/min x 0.75kw
Diameter 2.7m x Height 3.7m x Capacity
20m3 Alminium
Diameter 0.65m x Height 1.2m x Capacity
0.3m3 Stainless steel 316
Horizontal type
Diameter 1 .1m x Length 2m x Capacity
2m3 Alminium

Diameter 25mm x Head 10m x capacity
80//min. x 0.85kw
Liquid-contacting part Stainless steel 316
Diameter 50mm x Discharge pressure
2kg/cm2 x capacity 10 ~ 45 //min. x 2.2kw
Liquid-contacting part: PVC

1

1

1



1

2

2
1

2

1

1


1



2


2
      The  effects  of the dosage of hydrogen peroxide and ferrous sulfate as well as
the effects of flocculation on the filtration rate for the sludge sample listed in Table
2-2 are shown in Fig. 2-16 to Fig. 2-19.  From those results, the data obtained from
the leaf test and the pilot plant test were  confirmed to be reproducible by this actual
plant test, and  sludge could  obviously be dewatered up to  the  same level  as that in
the traditional process if flocculation is done carefully.
            Fig. 2-16 Relationship between Filtration Rate
                  and Dosage of Hydrogen Peroxide
Fig. 2-17 Relationship between Filtration Rate
     and Dosage of Ferrous Sulfate
                500  1000  1500  2000 ppm/slurry
                Dosage of Hydrogen Peroxide (HsOi)
      5    10   15   20 %/DS
  Dosage of Ferrous Sulfate |FeS04) lo Dry Solid.
                                           129

-------
        Fig. 2-18 Effect of Mixing Time on
               Filtration Rate
      E
      •&
                         80 rpm
Rotation Number
of Mixer
Mixing Time    1 to 5 min.
           Rotation Number
           of Flocculator  15 rpm
           Stirring Time  Continuous
              H	1	1	1	
               2345 min
               Mixing Time
                              Fig. 2-19   Effect of Stirring Velocity oh
                                       Filtration Rate
                                Rotation Number of
                                Mixer
                                Mixing Time      1 i
                                                         30 to 80 rpm
                                              Rotation Number of Flocculator 15 rpm 25 rpm
                                              Stirring Time          Continu- Continu-
                                                                    ous	
                                              30 40  50 60 70  80 rpm
                                              1,0 1.4  1.7 2.0 2.4  2.7 m/s peripheral
                                                                velocity
                                              Rotation Number and Peripheral
                                              Velocity of Flocculator
Table 2-2 Tested Sludge Properties

Digested and
Elutriated
Sludge
Raw Sludge
PH
7-8
6-7
Alkalinity
(ppm)
400 - 600
300 - 400
Dry Solid Con-
centration (%)
3-4
3-4
Content of Organic
Matter (%)
44-46
55-60
     Furthermore, the test using raw  sludge gave the following good results when
hydrogen peroxide and ferrous sulfate were added at the rates of 1,400 to  1,500
ppm to sludge in volume and at 13 to 19% to dry solid in weight respectively;
     The filtration rate was  11 to 19kg/m2/hr, the water content of the sludge cake
was 75 to 77% and the thickness of the dewatered sludge cake was 4mm.

2.4  RESULTS OF CONTINUOUS OPERATION AT THE FULL-SCALE PLANT
     On the basis of full-scale plant test results which showed that this process can
in fact  be used for dewatering process, the Nakahama sewage treatment plant has
been using this new process  exclusively since the end of October 1976.  At present
50 to 70 tons of dewatered  sludge cake per day can be obtained from slurry sludge
with a concentration of 3 to 4%  at a rate of 400 to  500m3 /day under the following
operating conditions; dosage of hydrogen peroxide - 1,200 ppm, dosage of ferrous
sulfate  - 15%,  mixing velocity - 80 rpm,  mixing time - 2.5 minutes and stirring
velocity - 15 rpm.
     As the sludge cake of 70 to  100 tons/day was produced by dewatering 300 to
400m3 /day of slurry sludge  with  the traditional process, it was considered that this
new  process achieved the aimed  for purpose.  Moreover, in the traditional process
the life of the filter cloth was 300 to 400 hours at most even though it was washed
with hydrochloric acid on occasion due to clogging of the filter cloth, but this new
process lengthened the life to over 700 hours with no-mesh-clogging, this being due to
the easy cloth-releasability of sludge cake. The life of the filter cloth will depend on
the strength of the fiber making up the  cloth.
                                       130

-------
2.5  COMPARISON WITH TRADITIONAL PROCESSING

     Though the time the new process was actually utilized in a full scale plant was
too short and the quantity of sample collected was too small to allow a complete
study, this new process was compared with the traditional one and discussed using
the data obtained in this fundamental research.

2.5.1   PHYSICO-CHEMICAL   CHARACTERISTICS   OF   THE  DEWATERED
       SLUDGE CAKE AND FILTRATE
     The characteristics of the dewatered sludge cake and filtrate obtained with this
new process and  with the traditional one are shown in Tables 2-3 and 2A respec-
tively.  The dewatered sludge cake obtained with this new process contains slightly
more water than that with the traditional one but sludge releasability from this new
process is excellent even at  a thickness of 2mm and the cake  contains more organic
substances, approximately the same level  as that in sludge used for dewatering, than
that with the traditional process.  Accordingly, its heat value per unit  weight is
higher so that it would be better for incineration when it is made a common prac-
tice.  On the other hand, pH of the filtrate indicates pH of 4 to 6  this being weakly
acidic, therefore accessory apparatuses  may  be corroded though  the corrosion de-
pends on these used materials.

Table 2-3 Properties of Dewatered Cake
^~^^-^_^ Sample
Measured iterrT~-^^^^^
Cake thickness (mm)
Water content of
Cake (%)
Content of organic
matter (%)
Heat value (Kcal/kg)
Digested and Elutriated Sludge
H2O2
2- 5
72-80
45
2,500
Ca (OH)2
3- 5
70-76
<40
< 2,000
Raw Sludge
H2C-2
2.5- 5
72-80
55-60
3,100
Table 2-4 Properties of Filtrate
Measured Item
PH
SS mg/1
BOD mg/1
COD mg/1
T-Fe mg/1
H2O2 Method
4-6
1 50 - 400
100-300
100 - 300
20 - 1 ,000
Ca (OH)2 Method
12-13
150-400
—
-
10-20
     The concentration of total iron in the filtrate from this new process sharply
fluctuates from 20 to  1,000 ppm. The reason is thought to be  that iron begins to
exude easily when the mole ratio of ferrous sulfate to hydrogen peroxide is over 1.
     In Osaka City, sludge is used for sea-reclamation at present as described above.
However if the sludge  is approved as a harmful industrial waste  (if it does not pass
the check test contained within the Harmful Industrial Waste Code established under
the Cabinet Order for  Implementation of the Waste Management Law) it can not be
reclaimed as long as it is given no special treatment.  Therefore, dewatered cakes
from this new process  and  traditional processes and their ash incinerated  with an
                                     131

-------
 electric furnace at 800° C in a laboratory were checked according to the established
 method, and this new process was  compared with the traditional process.  The
 results are shown in Table 2-5.

 Table 2-5 Heavy Metal Content and Results of Exudation Test in Dewatered Sludge Cake and Incinerated
         Ash.
\
Water con-
tent (%)
Organic
matter (%)
pH
Cd
Pd
T-Cr
Cr+6
Zn
Mn
Ni
Cu
As
T-Hg
T-Fe
CN
Dewatered cake
Ca (OH)2 method
Dry
solid
69.0
39.4
-
5.48
562
395
-
3425
1055
-
436
6.7
2.57
46600
35.4
'. Exuda-
•tion
-
-
12.8
0.01
0.20
ND
-
0,78
ND
-
0.87
ND
ND
0.30
ND
H2O2 method
Dry
solid
72.7
60.1
-
13.0
818
606
-
3510
563
879
768
2.2
3.4
58600
5.5
Exuda-
tion
-
-
-
ND
ND
0.04
0:09
3.0
6.1
0.40
0.05
ND
0.0015
43
ND
Incinerated ash
Ca (OH)2 method
Dry
solid
-
0.7
-
2.25
415
230
-
2800
320
-
315
3.94
ND
47500
0.37
Exuda-
tion
—
-
12.7
ND
0.13
ND
0.09
0.18
ND
-
0.34
ND
ND
0.40
ND
H2O2 method
Dry
solid
—
-
-
24.9
1068
1700
-
6870
1420
150
1520
13.7
0.13
97500
-
Exuda-
tion
—
-
6.7
ND
ND
0.1
0.09
ND
0.6
ND
ND
0.09
0.0007
0.1
-
Judgment criteria
for harmful indus-
trial wastes (for
exutation)



0.3
3

1.5




1.5
0.005

1
                                               Heavy metal content: ppm
     The content of heavy metals in the dewatered sludge  cake and  their ash from
the traditional process in which slaked lime is added is naturally lower and the pH of
the exudation from  the traditional process  is higher due to the addition  of slaked
lime so that it is difficult for heavy metals to  exude.
     But the  exudation  quantity of heavy metals in either process is  lower than the
regulated value.
     But care should be taken here  in that six valent chromium was detected in the
incinerated ash from this new process. It is presumed that the six valent chromium,
detected only in this case, can be attributed to the following;
     * high chromium content in the incinerated ash,
     * high lime  content in the filtrate  and  high lime content in the sludge used for
       dewatering due to returning of filtrate and waste from the slurry vat.
     At any rate the volume of dewatered sludge cake produced in this new process
will  be  smaller than  that in the traditional process, but the possibility that three
valent chromium  might  be oxidized (to six valent chromium)in the incineration of
sludge cake can not be denied.
     This problem will be further studied in full-scale plant operation  in the future.
2.5,2  DISINFECTANT ACTION OF  HYDROGEN PEROXIDE
     In  sewage  sludge, various bacteria, viruses and parasites are present.  The disin-
                                       132

-------
fectant action of hydrogen peroxide was examined by using the number of coliform
groups as a contamination index for fecal coliform bacteria, which is shown in Table
2-6.  The number of coliform groups measured in the sludge collected from the slurry
vat of the  full-scale  vacuum filter  is shown in Table  2-7.  In each cases, the
disifectant action of the hydrogen peroxide is recognized to be significant.

Table 2-6 Disinfectant Effect of Hydrogen Peroxide on No. of Coliform Group.
~"~~~~~- — — 	 Sample
Dosage of Hz 02 ~~ — — _______
0(mg/l)
1000
1500
2000
2500
Digested Sludge
1.5 x 10s (No./ml)
3.7 x 103
5. Ox 1Q2
5.0x10*
8
Raw Sludge
2.4 xlO6 (No./ml)
4.3 x 103
2,0 xlO3
3.0x10'
3
                Dosage of FeSO*: 6000mg/l

Table 2-7  Number of Fecal Coliform Groups in Sludge with Full-scale Plant
~~~^~-~^^^^ Sample No,
Kind of sampk~~~~— --^.^
Digested and elutriated
sludge
Chemical conditioning
sludge
1
3.8 xlO6
2.0 xlO2
2
5.8 xlO4
6,9.x 102
3
8,3 xlO3
3.Jxl02
2.5.3  WORKING ENVIRONMENT
     The working environment in terms of such things as dust or nasty odors often
becomes a problem while sludge dewatering operation. There is no dust problem in
this new process which handles ho powdery lime for sludge conditioning.
     For  odors, 5  components, which were thought  to be released  from sewage
sludge, of 8 substances of which the maximum contents are regulated by the Malo-
dor Control Act were selected and their concentration measured while  the filter was
being operated. The results are shown in Table 2'8.  From those results, this new
process was considered to be effective for ammonia odor control,  Though the posi-
tive deodoring effect by this  new process could  not be recognized only from the
above results, it was significantly felt.
                                     133

-------
Table 2-8 Result of Malodoreous Substances Measurement around Filter
N\. Sample
Measured N.
Item X^
Hydrogen
sulfide
Methyl
mercaptan
Methyl
sulfide
Trimethyl
amine
Ammonia
HlOa method
Sludge-feed-
ing side
(inside slurry
vat)
ND
ND
1.6
m
ND
Cake-releasing
side around
drum
ND
ND
0.4
ND
ND
Ca (OH)2 method
Sludge-feed-
ing side
(inside slurry
vat)
ND
0.3
1.4
ND
400
Cake-releasing
side around
drum
ND
ND
0.5
ND
ND
Regulated
standard value
on site
boundary
20 - 200
2-10
10-200
5-70
1000 - 5000
                                                   Unit:  nl/l = ppb

2.5.4  ECONOMICS
     Table 2-9 shows the rough calculation of the required cost for this process in
comparison with the  traditional process when  100 tons of sludge as dry solid in
weight per day is treated. Though some of operation and maintenace costs were dif-
ficult to estimate over a long term, it was proved that within the limits indicated in
Table 2-9, this process was feasible from an economic standpoint as well.
                                     134

-------
Table 2-9 Comparison of Dewatering Process by Using Hydrogen Peroxide System with Slaked Lime System
\
It
Chemical Conditioning Method
em\^ Kind of Sludge
Raw Sludge (dry solid)
Digested Sludge (dry solid)
Chemical Dosing Rate
Sludge Cake Water Content
Heat Value
Products
Incinerated Ash Products
Cost Comparison
Construction Costs
Operation and Maintenance Cost Per Year
Depreciation & Interest
Chemical Cost
Supplemental Fuel Cost
Boiler for Digester
Heating
Furnace for Incinerator
Ultimete Disposal Costs of Ash
Electricity Water Supply Costs
Repair Material
Labor Cost
Total
Operation and Maintenance Cost
Per 1 Ton of Dry Solid
H2O2 + FeSO4
Digested Sludge
100 t/day
70 t/day
H2O2: 2.5 -5%
(average 3.75%)
FeSO4: 10-20%
(average 15%)
70 - 80% (average- 75%)
average 2143 Kcal/kg
280 t/day
52 t/day
12,944 million yen
600 million yen
H2 02 : 70 t/day x 0.037 5
/t= 273,750,000 yen
FeSO4: 70 x 0.15 x
OY x 365 x 800
= 6, 130,000 yen
Total = 279, 880,000 yen
36.65 1/t x 100 t/day x
365 x 33.80 yen//
= 45 ,220,000 yen
110.55 x 100 x 365 x
33.80= 136, 390,000 yen
Total = 181,610,000 yen
52 t/day x 365 x 4,922
yen/t -93,420,000 yen
¥318,350,000
¥83,000,000
¥400,000,000
¥1,956,260,000
¥53,600
Raw Sludge
100 t/day

H2O2: 2.5 - 5%
(average 3.75%)
FeSO4: 10 - 20%
(average 15%)
75 - 80% (average 77%)
average 3000 Kcal/kg
435 t/day
52 t/day
8,203 million yen
410 million yen
H202: 100 t/day x 0.0375
x Q-|J x 365 x 10,000yen/
t- 391, 100,000 yen
FeSO4: 100 x 0.15 x
Oy x 365 x 800
= 8,760,000 yen
Total = 399,860,000 yen

69.08 1/t x 1 00 t/day x
365 x 33.80 yen//
= 85,220,000 yen
Total = 85,220,000 yen
5 2 t/day x 365x4,922
yen/t = 93,420,000 yean
¥178,380,000
¥63,000,000
¥305,000,000
¥1,534,800,000
¥42,100
Ca (OH)2 + FeSO4
Digested Sludge
100 t/day
70 t/day
Ca (OH)2 (average 25%)
FeSO4 (average 5%)
65 - 75% (average 72%)
average 1714 Kcal/kg
313 t/day
78.4 t/day
13,798 million yen
645 million yen
Ca(OH)2: 70 t/day x 0.25
x 365 x 12,500yen/t
= 79,840,000 yen
FeSO4: 70 x 0.05 x
~ x 365 x 800
= 2,040,000 yen
Total = 8 1,88 0,000 yen
36.65 1/t x 100 t/day x 365
x 33.80 yen/t
= 45 ,220,000 yen
130.97 x 100 x 365 x
33.80= 161,580,000 yen
Total = 206,800,000 yen
74.8 t/day x 365 x 4,922
yen/t = 134,380,000 yen
¥318,230,000
¥ 90,000,000
¥400,000,000
¥ 1,876,290,000
¥51,400
    2.6  CONCLUSION
        The  merits and  the demerits of this new process are summarized as follows
    along with the problems to be solved in the future.
    Merits:
        1.  Smaller quantity of dewatered sludge cake and incinerated ash.
        2.  Higher heat value per dry solid base.
        3.  Simpler equipment, easier operation and maintenance.
        4.  No need to adjust the conditions for the addition of chemical with a slight
           variation in sludge properties and sludge concentration.
        5.  Higher sludge recovery rate due to the easy releasability of dewatered cake,
           longer life of  filter cloth, and no  need of washing filter cloth with acid solu-
           tion.
        6.  Better working environment.
                                          135

-------
Demerits and problems:
     1. Slightly higher water content  in  dewatered sludge cake  than that in the
       traditional process.
     2. Necessary to prevent the apparatuses from  coming into contact with the
       liquid due to the possibility of corrosion on  account of the weak acidity of
       sludge.
     3. Slightly higher treatment cost than that with the traditional process.
     4. Slight concern for the stable supply of hydrogen peroxide the manufacturers
       of which being oligopolistic.
     The  method  and engineering  for treating  sludge should be  comprehensively
discussed  as regards ultimate disposal of sludge  and  effective utilization of the
sludge. In the future, this new process will be studied further in terms of systematiz-
ing the treatment and disposing of the sludge. From this point on, together with the
disposal of waste gas at incineration process, the prevention of apparatus corrosion,
and the structure of the incinerator to be used, the quantitative analysis of the ad-
ded chemical and the mixing conditions that improve the process economically will
be made the subjects of study.
                                    136

-------
    CHAPTER 3.  SURVEY OF ECONOMICAL AND TECHNICAL PER-
                 FORMANCE FOR EMISSION CONTROL EQUIPMENT
                 INSTALLED WITH SLUDGE INCINERATOR
3.1   Introduction	138
3.2   Historical Review of Emission Standards	144
3.3   Auxiliary Fuel and Design Capacity of Incinerator	148
3.4   Case Studies on Performance of Emission Control Facilities	150
3.5   Tentative Proposal for Standard Emission Control System in Sludge
     Incinerators  	159
                                137

-------
3    SURVEY OF ECONOMICAL AND TECHNICAL  PERFORMANCE FOR
     EMISSION CONTROL EQUIPMENT INSTALLED WITH SLUDGE
     INCINERATOR
3.1  INTRODUCTION
    At  the U.S-Japan  4th conference on Sewage Treatment Technology,  a brief
report was presented on the treatment and disposal of sewage sludge in Japan.  In
this report,  it is noted  the remarkable progress of construction of sewage facilities
in Japan accompanied by a very rapid increase in the amount of sewage sludge which
is to be disposed.  See Table 3.1.

                      Table 3.1 Annual Change in Sludge
\
1967
1968
1973
Total
(xlO4 persons)
10,024
10,141
10,871
®
Sewered
Population
(xlO4 persons)
1,112
1,283
2,110
No.
of
S.T.P.
142
175
253
©
Treated Sew-
age Volume
(M-mVyr)
2,371
2,691
5,733
©
Sludge
(99% moisture)
(M;m3/yr)
22,93'
28,19
104,12
©/®
(%)
0.97
1.05
1.82
(m3 /cap/day)
0.58
0.57
0.74
     Sewage sludge in 1953 and sewage volume are listed in Table 3.2.

               Table 3.2 Generated Sludge Volume by Treatment Process
                                                                      (1973)
Process
Activated Sludge
process
Trickling Filler
Process etc
Primary Treat-
ment Process
etc
Total
No.
of
S T P
166
69
18
253
«®
Sewage
Volume
1 xlO3 mj/yr)
3.760,401
1.559.601
412.731
5,732,733
®
Sludge
Generated
(xlO'm'/yr)
64,770.3
12.589.5
2,861 4
80.221.2
©
Night Soil
(x]0!m!/yr)
2,688.1
866.4
201 7
3,756.2
®<&
(xlO'm'/yr)
67,458.4
13,455 9
3,063.1
83,977.4
©
Sludge Volume
(99% moisture)
(xlO!m»/yr)
86,567.8
12,916.7
4,630.5
104,115.0
©
Night Soil
(99% moisture)
(xlO'm'/yr)
6,720.3
2,166.0
504.3
9,390.6
®+©
(xlO'm'/yr)
93,288.1
15,082.7
5,134.8
113,505.6
®®
(%)
1.72
0.81
0.69
1.40
®®
(%)
2.30
0.83
1.12
1.82
    Approximately 66% of total treated sewage are treated by secondary treatment,
activated  sludge process,  27%  by modified  or trickling filter  process and 7% by
primary treatment and 81% of the sewage sludge is generated  by secondary treat-
ment process.
    So the ratio of the amount of sewage sludge generated to the amount of treated
sewage is 1.72% in secondary treatment, 0.81% in intermediate and 0.69% in pri-
mary treatment.
    That is, the  secondary treatment  process generate greater amounts of sewage
                                   138

-------
sludge which contain relatively higher organic content.
    Table 3.3 shows what ways are selected to dispose of sewage sludge.
                          Table 3.3 Sludge Disposal
                                                   (1973)
Process ~^^^^
Reclamation
(Land, Sea)
Disposal on Site in
S.T.P. at the Sewage
Treatment Plant
Dumping into
Ocean
Soil Conditioning to
Farm Land
Others
Total
Sludge Volume
(lO'mVyr)
1,108.5
158.9
175.2
158.0
110.2
1,710.8
Share
'(%)
64.8
9.3
10.2
9.2
6.5
100.0
     Land-filling is the most common practice of sewage sludge disposal, with ocean
 dumping and agricultural land  application  both accounting for about  10% each.
 However, at the present, ocean dumping has been only practiced at Kitakyushu,
 which share very small.
     In March 1976, JSWA  conducted a survey on sewage sludge incineration facili-
 ties in Japan are summarized in Table 3.4.
     About 25% of sewage sludge, and about half of the dewatered  sewage sludge
 are incinerated. Most of these incinerators were located in the 3 major metropolitan
 areas (see Table 3.5).
     This is the season why it is very  difficult to find the site to dispose sewage
 sludge and  efficiency of transportation  is very low by heavy traffic conjestion in
 metropolitan areas.
     Characteristics of sewage  sludge  and  the performance  of sludge treatment
 during 1975 in Tokyo, has been summarized in Table 3.6.  44% of the sewage sludge
 generated in Tokyo is incinerated, and then disposed to land reclamation site in the
 bay. Since sewer system in Tokyo is employed combined system, the contents of
 organic matter in the sludge is as low as 40%.  In another words inert matters with
 surface water are induced to sludge.
     The incineration of sewage sludge  consumes a large amount of energy and as
 will be described later, regulation on  atmospheric emissions are becoming more and
 more stringent, it is very important to study about performance of actual emission
 control equipment of sewage sludge incinerator. In 1975 Research and Technology
 Development Division of JSWA embarked on a program of research and development
 on the treatment and disposal of sewage sludge. This program includes evaluation of
 the land application of sewage sludge as soil conditioner, pyrolysis, and incinerators
 itself etc. This paper is an interim report  on this subject and this project will be
 completed in 1978.
                                       139

-------
Table 3.4 Inventory of Incineration in 1975
                                                                                          (March 1976)
Prefecture
Hokkaido
Tochigi
Saitama
Chiba






Tokyo







City
Sapporo
Sapporo
Sapporo
Utsunomiya
Kawaguchi
Arakawa
Chtba
Ichikawa
Matsudo
Narashino
Tokyo










Hachioji
Machida
Tamagawa
Tamagawa
Name
of
S.T.P.
Soseigawa
Toyohiragawa
Shmkawa
Tagawa
Ryoke
Arakawasagan
Chuo
Ichikawa
Shumatsu
Koganehara
Sodegaura
Sunamachi




Odai



Shmgashi

Kitano
Tsurukawa
Minamitama
Kitatama
Sewer
System
Combine
Combine
Separate
Combine
Separate
Combine
Combine
Combine
Combine
Separate
Combine
Separate
Separate
Combine




Combine



Combine

Combine
Separate
Separate
Combine
Treatment
Process
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Agro
Accelerater
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge




Activated Sludge



Activated Sludge

Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Types
of
Sludge
Raw
Raw
Raw
Digested
Raw
Digested
Raw
Digested
Raw
Raw
Raw
Raw
Digested




Raw
Digested



Raw

Digested
Raw
Raw
Raw
Types
of
Dewatering
Va
Fp
Fp
Va
Va
Fp
Va
Va
Va
Va
Va




Va



Va

Va
Cf
Fp
FP
Multi-
health
Furnace
17t/Dx3



35t/Dxl
40t/Dxl
50t/Dxl
20l/Dxl
lOt/Dxl
5t/Dxl
150t/Dx]
150t/Dxl
200t/Dxl
250t/Dxl
300t/Dxl
lOOt/Dxl
1501/Dxl
180t/Dxl
180t/Dxl
2001/Dxl
300t/Dxl

5t/Dxl


Fluid -bed
Incinerator





















40t/Dxl

20t/Dxl
40t/Dxl
Rotary
Drying
Incineration



30t/Dxl





















The Rest

30t/Dxl
42.5t/Dx2






















Dewatering
Cake
(t/year)
40.483
14,301
16,910
4,104
5,036
8,080
10,488
3,832
No Data



> 498,770




' 179,145

1, 57,985
J
10,134
No Data
2,977
6,586
Moisture
Content
Average
76.4
50.5
44.1
78.1
70.5
63.0
No Data
75.0
No Data

Raw 79.4
Digested 79.1








20.8

78.0
No Data
63.5
61.4
Incinerated
Sludge (Wet
Cake, t/year)
2,471
10,972
16,230
3,197
5,345
6,392
^^^
1,032
^^^
^-^
50,450
42,812
67,240
77,331
90,765
16,003
33,363
51,606
57,408
50,370
7,615
6,952
^^^
2,900
5,776
Auxiliary
Fuel
(kS/yeai)
(B) 145
(B)*l,256
(B)*l,369
263
251
337
^^
161
\^^
^^
1,712
1,382
2,347
1,429
1,616
345
1,524
980
573
2,985
472
716
^^"
241
782
Digested
Gas
mj/year)













1,412,420
3,434,250
1,401,350
7,430
1,270,810
2,504,120


1,300



Remarks
Suspension of
Operation)
•Heat Treat-
ment
•Heat Treat-
ment



(Suspension of
Operation)

(Suspension of
Operation)
(Suspension of
Operation)












(Suspension of
Operation)



-------
Prefecture

Kanagawa


Toyama



Shizuoka
Aichi
Kyoto
City
Kawasaki
Yokosuka
Odawara
Toyama
Takaoka
Kosugimachi
Gifu
Gifu
Shizuoka
Hamamatsu
Nagoya
•
Nagoya
Ichinomiya
Bisai
Kyoto





Name
of
S.T.P.
Iriezaki
Shitamachi
Kotobukicho
Joka Center .
Yotsuya
Daikakusan
Kokubu
Nanbu
Takamatsu
Chubu
Yamazaki

Shibata
Tobu
Bisai
Toba





Sewer
System
Combine
Combine
Separate
Combine
Separate
Combine
Separate
Separate
Separate
Combine
Combine
Separate
Combine

Combine
Combine
Separate
Combine





Treatment
Process
Activated Sludge
Activated Sludge
Activated Sludge
High Rate Trick-
ling Filter
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge

Activated Sludge
High Rate Trick-
ling Filter
Activated Sludge
Activated Sludge





Types
of
Sludge

Raw
Raw
Raw
Digested
Raw
Digested
Raw
Raw
Raw
Raw
Raw
Digested
Raw
Digested

Raw
Raw
Raw
Raw
Digested





Types
of
Dewatering
Va
Cf
Va
Va
Va
Va
Va
Va
Va
Va
Va

Va
Va
Va
Va





Multi-
hearth
Furnace


40t/Dxl
18t/Dxl
20t/Dxl




30t/Dxl
150t/Dx2
40I/DX2
80t/Dxl
150t/Dx2
5t/Dxl
lOt/Dxl
30t/Dxl
60t/Dxl
60t/Dxl
60t/Dxl
150t/Dxl
150t/Dxl
150t/Dxl
Fluid-bed
Incinerator

40t/Dxl




50t/Dxl
50t/Dxl













Rotary
Drying
Incineration
D.S.
6t/Dx5







30t/Dx2












The Rest





5.2t/Dxl















Dewatering
Cake
(t/year)
13,350
2,994
7,131
2,733
4,630
650
4,768
4,951
8,284
5,921
107,836
No Data
39,240
4,286
3,180
\

, 134,330


,
Moisture
Content
Average
71.0
74.9
77.0
75.0
78.0
75.6
83.2
77.1
70.0
75.0
74.8
No Data
78.1
70.0
60.0
77.3
77.3
77.3



Incinerated
Sludge (Wet
Cake, t/year)
13,350
2,994
6,708
1,307
4,630
250
4,980
3,955
7,212
2,608
59,956
^-^^
38,722
632
900
1,779
4,618
12,659
39,181
38,303
37,790
Auxiliary
Fuel
(ks/year)
1,150
255
916
2.7
120
95
469
501
347
521
2,202
^^
1,657
(B) 29
90
47
310
674
1,660
1,632
870
Digested
Gas
(m'/year)









422,980'





140,960




798,528
Remarks



(Suspension of
Operation)

(Suspension of
Operation)



'Keeping
Warm

(Suspension of
Operation)










-------
t-0
Prefecture
Osaka
Hyogo

Hiroshima
Oita
Wakayama
Okinawa
City
Osaka
Osaka
Sakai
Kishiwada
Ikeda
Suita
Tondabayashi
Sasayamacho
Neyagawa
Neyagawa
Aigawa
Kobe
Nishmomiya
Ashiya
Akashi
Kakogawa
[nagawa
Hiroshima
Oita
Wakayama
Okinawa
Chubu
Name
of
S.T.P.
Tsumori
Hoshutsu
Sanpo
Isonoue
Ikeda
Minami Suita
Kongo
Konoike
Kawamata
Chuo
Suzurandai
Nishinomiya
Ashiya
Hunaue
Ogami
Harada
Enami
fiaiakawa
Shioya
Isahama
Sewer
System
Combine
Combine
Combine
Combine
Combine
Separate
Combine
Separate
Combine
Separate
Combine
Separate
Combine
Separate
Separate
Combine
Combine
Separate
Combine
Combine
Separate
Combine
Separate
Combine
Separate
Combine
Separate
Treatment
Process
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Activated Sludge
Types
of
Sludge
Digested
Digested
Raw
Digested

Digested
Raw
Raw
Ra>v
Raw
Raw
Raw
Digested
Raw
Digested
Raw
Raw
Raw
Raw
Digested
Raw
Raw
Raw
Raw
Types
of
Dewatering
Va
Va
Fp
Va
Va
FP
Va
Va
Fp
Va
Va
Va
Va
Va
Fp
Va
Va
Va
Va
Cf
Multi-
hearth
Furnace
lOOt/Dxl
lOOt/Dxl
200t/Dxl
50t/Dxl
70t/Dxl
15t/Dxl
25t/Dxl
50t/Dxl

70t/Dxl
60t/Dxl
40t/Dxl
15t/Dxl
30t/Dxl
50t/Dxl
27t/Dxl
20t/Dxl
20t/Dxl
50t/Dxl
50t/Dxl
lOt/Dxl
60t/Dxl

Fluid-bed
Incinerator






15t/Dxl












10t/Dx4
Rotary
Drying
Incineration




















The Rest



















,.••
Dewatering
Cake
(I/year)
11,766
45,802
21,600
4,253
4,419
5,641
3,881
6,385
m3/year
9,033
5,091
1,399
18,052
3,630
3,498
1,651
28,865
20,741
2,400
11,892
444
Moisture
Content
Average
65.0
63.0
68.0
72.5
80.0
65.0
No Data
74.6
69.0
75.5
20.7
57-77
77.5
78.1
65.0
75.8
77.7
75.0
78.0
73.4
Incinerated
Sludge (Wet
Cake, t/year)
10,032
18,148
^^^
^^-^
4,119
^^^
^^"
5,295
9,033
•9,834
468
2,730
3,630
3,498
1,141
24,381
20,741
2,400
10,255
444
Auxiliary
Fuel
(k8/year)
184
"1,183,176
^^
^^
327
^^
^-^
449
280
667
98
122
216
546
63
3,569
1,078
208
No Data
(C) 192
Digested
Gas
(m'/year)
1,350,480










285,288








Remarks

•Gas
Suspension of
Dperation)
(Suspension of
Operation)

(Suspension of
Operation)
(Suspension of
Operation)


Included Taka-
tsuki Plant










                                                   Note:  Raw . . . Raw Sludge
                                                                                     Digested . -. Digested Sludge
                                                                                                                        Cf ... Centrifuge
                                                                                                                                                Va . . . Vacuum Filter
                                                                                                                                                                            Fp . . . Filter Press

-------
                                        Table 3.5


                                        Whole State
                                            (A)
                               Three
                         Metropolitan Area
                                (B)
                      B/A x 100
         Incinerated Sludge    x!03W.T/yr
                1,015
           850
    84
        Number of Furnace
                                              92
                                                            40
                                              45
                  Note: Three metropolitan - Tokyo, Nagoya, Kyoto-Osaka
             Table 3.6  The Status of Sludge Treatment at Metropolitan Tokyo
                                                                                     (in 1975)
Plants
Shibaura
Mikawashima
Odai
Sunamachi
Ochiai
Morigasaki
Shingashi
Total

®
(2)
(3)
®
®
©
®
©
(3)
®
©
©
®
@
(3)
®
©
(3)
)
1,022,380
3,720
2,790
^^-— "^
^_^-~- ~~"
^^- — -~~~~
1.144,340
4,680
•3,140
489,810
4.460
•1,430
^^-— "'
^^^^^
^_-— — ~~~
^^^^~
__^-" 	
	 _^~-~-~~\
^^^-^~~
^_^-- "
_^
2,656,530
-

Sludge
Cake
(tons)
123,168
562
337
^_^^"
^_^^--~~~
^^^-— ~~
179,145
772
489
498,770
1,905
1,363
^_^-^-^'
^^^~~~
i__-——^'
\ 160,424
831
438
57,985
236
163
1,019,492
-
-
Slaked
Lime
(kg)
7,057,080
32,900
19,282
^^^
^^-^
^_--— """
10,355,900
50,660
28,300
26,772,970
103,680
73,150
^^-^^
^__-— -""
^^-^^
9,145,380
46,590
24,990
2,718,000
12,500
•7,635
56,049,420
-

Ferric
Chloride
(kg)
3,071,010
14,010
8,391
^^-^^~
^^-— -"'"
_^,^—-^'
6,943,100
20,120
18,970
16,319,180
68,390
44,588
_^-—-^
^_^----"~~~
^^~~~~^
3,878,570
19,430
10,600
990.140
5,030
•2,781
31,202,000
-
-
Incinerated
Cake
(tons)
^_^^~"~
_^^^^~~
^_-^-'~~~~
^^^^~
^_-^^~~"~
^^^^
179,145
-
-
498,770
-

_^-—— -^
^^--^
__^-^~~"
^^--~~^
^^^^
___^— -~~~
57,985

-
735,900
-
-
Remarks
Not
Incinerate
Transported
to Sunamachi
by Pipeline


Transported
to Odai
by Pipeline
Not
Incinerate


Note: 0	Yearly Total
(2)	Daily Max
(3)	Yearly Mean per Day
      * Average
          Mikawashima
             Odai
           Sunamachi
            Ochiai
           Shingashi
                                    Analysis of Sewage
                         Raw Sewer
                            SS
                           (mg/B)
                           153
                           115
                           109.5
                           123
 89
          Thickened Sludge
              Moisture
                                           97.5
                97.4
                95.2
        Sludge Cake
         Moisture
                                                           77.7
                                                           79.1
                                                           80.8
Sludge Cake
  Organic
                                                                         49.3
                                                                         36.3
                                                                         40.4
                             1975, Yearly Average
        The Annual Report of the Sewerage Works Bureau of Tokyo Metropolitan Government
                                           143

-------
3.2  HISTORICAL  REVIEW OF EMISSION STANDARDS
     Incinerators are required to be equipped with emission control equipment in
order to meet the standard set by Air Pollution Control Law. The survey conducted
by  the JSWA showed that installation costs of the emission control facilities  ac-
counted for as much as 30 to 50% of the incinerators itself.

                Table 3.7 Chronological Regulatory Standards on Control
Law
Smoke and
Soot Regula-
tion Act
(1962-6)







Air Pollution
Contrul Act
(1968-6)










Promulgate
Date
1963-7


1968-3
1968-12
1969-2

1969-7



1971-6


1972-1




1973-1


Object
Area
5


20
27
35

35



The Whole
State


The Whole
State




The Whole
State


SOx
REC0:
0.22% (2200 ppm)
Part 0.28%

0.18% ~ 0.28%
RTE(2):
K = 20.4 ~ 29.2
K= 11.7 ~ 26.3
US® :
K= 11.7 -26.3
UES: (New Facility)
K = 5.26

US:
K= 11.7 -26.3
UES (D : (New
Facility)
K = 5.26

US:
K=7.01 -22.2
UES:
K= 2.92-5.26


US:
K = 6.42~ 22.2
UES:
K= 2.92 -5.26

Particulate Matter
REC: 0.6 - 2.0
e/m3


REC: 0.6 - 0.6
g/m3
REC: 0.6 - 2.0
g/m3
REC: 0.6 - 2.0
g/m3

REC: 0.6 - 2.0
g/m3


Ul: ,.1 -
0.8 g/m3
UES: 0.05 -
0.4 g/m3

US: 0.1 ~
0.8 g/m3
UES: 0.05 -
0.4 g/m3


US: 0.1 ~
0.8 g/m3
UES: 0.05 -
0.4 g/m3

Harmful Matter
No


No
No
No

No

REC:
Cd, 1 mg/m3
a, HCI,
30 - 80 mg/m3
F.I - 20 mg/m3
Pb.10-30 mg/m3
REC:
Cd, 1 mg/m3
a, HCI,
30 - 80 mg/m3
F 1 - 20 mg/m3
Pb, 10-30 mg/m3
REC:
Cd, 1 mg/m3
a, HCI,
30 - 80 mg/m3
F, 1 - 20 mg/m3
Pb, 10~30mg/m3
Note: (D  REC - Regulation of Emission Concertration
     Q>  RTE - Regulation of Total Emission
     ®  US  - Uniform Standard
     @  UES - Unusual Emission Standard
     Installation of Sewage sludge incinerator began in Japan around 1964, and the
emission  control  regulations were  based  on the soot and dust control  law 1962.
The standards were not so strict ones, so  exhaust gas was treated by a water spray
type scrubber (cooling tower) which was sufficient to reduce soot and dust.
     In  1976, legislature on  Basic Law  for Environmental Pollution control  was
enacted in 1969, followed by Air Pollution Control Law.
     By 1970, the general populace had become keenly aware of pollution problems
and under circumstances which increases in victims from photo-chemical smog, more
                                     144

-------
stringent standard are required.  So in December  of the  same year during the so-
called  "Pollution Diet",  almost national laws relating to pollution control was
revised. The effect of the revision to the Air Pollution Control Law was to extend
the designated areas covered by the provisions of the Soot and Dust Control Act to
include the whole country. All smoke generating processes in all plants throughout
the country (except mining) had to meet the same  emission standards designated by
law. Table 3.6 show how the standards  have changed within recent years.  The
emission control levels relevant to sewage sludge incineration are listed in Table 3.8.

                 Table 3.8-1 Emission Standards (Solid Waste Incinerator)*
®
Pollutant
(1) Sulfur Oxdie






















(2) Soot and Dust

(3) Harmful
Substances














(4) Specially
Harmful
Substances
(28 Substances)
(5) Heavy Metals


©
Uniform Standard
q -Kx 10° He'
Where
q: Hourly Volume
of Sulfur Oxides
Emitted in Units
of Nm!
H: Effective Height
of Stack
K: Varies According
to the Region
K Ranks are:
3.0,3.5,4.67
6.42,8.76,11.7
14.6, 17.5










Over 40,000 Nm'/hr
0.2 g/Nm! Max.
Under 40,000 Nm'/hr
0.7 g/Nm1
1. Cadmium and Its
Compound 1.0 mg/
Nm'
2. Chlorine 30 mg/
Nm'
3. Hydrogen Chloride
80 mg/Nm1
4. Fluorine, Hydrogen
Fluoride and Silicon
Fluoride 1 ~ 20
mg/Nm1
5. Lead and Its Com-
pound 10-30 mg/
Nm1
6. Nitrogen Oxides
100~480ppm
No
(for the present
No
(for the present)

®
Special
Emission
Standards
K ranks are:
1.17
1 75
2^34




















0.1 g/Nm1
0.2 g/Nm'
No















No
(for the
present)
No
(for the
present)
®
Progressive Emission
Standards
Q= a-Wb
Q: Hourly Volume of
Sulfure Oxides
Emitted in Units of
Nm1
W: Fuel Conseemed (kC/
hr)
a: Value designated
Prefectural Govern-
ment
b: 0.8 ~ 1.0
Maximum Pollutants on
the Ground
0= Cm X0o
w= Cmo v
Qo: Sulfur Oxides (in
Nm3/hr)
Cm: Maximum Pol-
lutant Concentra-
tion Disignated by
Prefectures Govern-
ment
Cmo: Maximum Pol-
lutant Concen-
tration Depending
on Qo (Vol %)
No

No















No

No


(D
Special Progressive
Emission Standard
Q=a.Wb + r-a(W + Wi)b-Wb
W, i, a, b as Same as Column
Wi: Aditional Fuel After
Designated Date (kfi/hr)
r: 0.3 -0.7
Maximum Pollutant Concentra-
tion
Cm Qi
Cml
When Additional Facilities are
Equipped
Cm
Q = Cmo + Cmi (Q° + Qi)
Qo, Cm, Cmo as Same as
Column (?)
Qi : Additional on Sulfur
Oxides (in Nm3/hr)
Cmi: Max Pollutant Con-
centration Depend-
ing on Qi (Vol %)




No

No















No

No


©
Local
Ordinaries
No






















Yes

Yes















No

No


©
Remarks
K= 1.0, as Guideline
in Some Prefectures





















0.01 g/Nm3 as
Guideline in Some
Prefectures





















 * This Standards will be Applied for the Incinerator which Capacity is Above 200 kg/hr or Grate Area is Above 2 m!.
                                       145

-------
Table 3.8-2 Regulatory Standards on Offensive Odor Substance
®
Substances
(J) Ammonia
(2) Methyl Mercaptan
(D Hydrogen Sulfide
@ Methyl Sulfide
(D Dimethyl Sulfide
(6) Trim ethyl Amine
@ AcetAldhyde
® Styrene
(D
Regulatory Standards
on Boundary Lines
5 ppm
0.002 ~ 0.01
0.02 ~ 0.2
0.01 ~ 0.2
0.009 ~ 0.1
0.005 ~ 0.07
0.05 ~ 0.5
0.4- 2

When Ammonia, Hydrogen Sulfide, Trimethyl Amine
are Concern, Stack Gas Regulatory Standards are
Calculated by Following Equation.
q = 0.108 xHe2 • Cm
q: Flow Rate of Pollutant (m3/hr)
He: Ehective Height of Stack (m)
Cm: Standards as Column (2)
      Table 3.8-3  Emission Standards of Nitrogen Oxides
Facilities










4. Portland Cement
5. Nitric Acid Production
6. Coke Oven



Solid Fuel
Others









Gas Volume
(104Nm3/hr)
1^ <10
10<
1<
1 <
1 < <10

10< <4
1 < <4

4<
10<
All Facilities
10<~
Standards
ppm
130
100
480
150
150

100
150

100
250
200
200
On (%)
5
5
6
4
11

11
6

6
10
Os
7
The NOX Emission Concentration shall be Converted through the Following Equation (Except in the Case
of Nitric Acid Production Facilities).
c- 21 -On
C 21 - On A Cs
Where
C: NOX Emission Concentration (ppm)
On: Oxygen Concentration in Stack Gas
Os: Actual Oxygen Concentration in Stack Gas
Cs: Actual Nitrogen Oxides Emission Concentration (ppm)
                          146

-------
     In 1972, scope of  standard values were settled  according  to  the Offensive
Odor  Control  Law.  Ammonium,  hydrogen sulfide,  and trimethylamine  were
stipulated according to concentrations  in the air at boundary line,  while methyl
sulfide, trimethylamine, acetoaldehyde, and styrene were stipulated as  concentration
on  the ground.  According to the  Offensive Odor Control Law, local prefecture
designated  the relevant areas,  and  determined appropriate standards.  By  1977,
standards had been applied in  450  cities, 463 towns, and 69 villages in 44 prefec-
tures,  plus the Tokyo  metropolitan area and  10 cities designated by government
ordinance.   As an  example, standard applied in Tokyo metropolis are shown in
Table  3.9.
                  Table 3.9  Regulatory Standards of Offensive Odor
                                                          3)
                                                          (Tokyo)
^"~-\^^ Land Use
(D Ammonia
(2) Methylmercapten
(D Hudrogen Sulfide
® Methyl Sulfide
(5) Trimethylamine
® Acetaldehyde
@ Styrene
(D Methyldisulfide
Industrial Area
Semi Industrial Area
(ppm)
2
0.004
0.06
0.05
0.02
0.1
0.8
0.03
Residental Area
(ppm)
1
0.002
0.02
0.01
0.005
0.05
0.4
0.009
     Due to more stringent control of exhaust gas sewage sludge incinerators, the
emission control systems has much improved.
     The chronological changes in these systems have been illustrated in Fig. 3.1.
     System (1),  adopted  from around  1964,  employed washing by water in a
scrubber for cooling and dust removal. It was quite sufficient at the time to reduce
dust levels to the 0.7 g/Nm3 which value designated by standard.
     System (2) in 1970, adoptation of dust removal level was improved to 0.2 g/Nm3,
and because of the lower K value, for control sulfur oxides an alkali cleanser was
added after the scrubber.
     System (3) was adapted in  1972 due to a new local ordinances that incinerators
be equipped with electrical dust  precipitator (in Osaka and other some prefectures).
     System (4) adopted an alkali cleansing, plus after burning for deodorery, due to
the implementation of the Offensive Odor Control Law in 1972.
                                     147

-------
      Fig. 3.1  Chronological Variation of Emission Control System for Sludge Incinerator
   (0
   (2)
   (3)
   (4) a.
MHF ^ —

MHF |—

MHF j—

Exhausted \___
Gas Fan |~™
Scrubber \__ Chinu

Exhausted \__
Gas Fan \

Scrubber j—

MHF \-| Scrubber V-

MHF \—

MHF N— '

FBH \—


Scrubber ^ —

\ 	 1 (Alkali)
Scrubber |-j Ablotption

(Alkali) \__ Exhaus
Absorption Column | GasFai

(Alkali) \__ EP
Absorption Column |

(Alkali) \J EP
Absorption Column [ ]

. . . \ 	 l(Acid) \_ (Alkali)
Scrubber | |Ab!orpliol, Column f^ Absorption

iHeat \
Exchanger.) |~~


Heat \
Exchanger-2 j— Cyclo

1
L
ZJ

_ . i-"" Chimny i
Column] |

«ed \J chimny \

V sfsr VI <*«* ^

\ Extuiuted \ 	 1 Afterburner \ 	
|~" Gas Fin |H (Deodrizition) 1 1
1

^ Chimny ^

\__ ..,. \ 	 I Exhausted \ 	
Columnp EP p] Gas Fan ]~]
1

1 	 EP N — Chimny \

\ ...... \ 	 Absorption \ 	
ne Y~ Scrubber ^p- ColuTm ^-j


\ Exhausted \ 1 „ . \
|— Gas Fan pj """'' 1
        Note MHF - Multi Hearth Furnace
           EP   Electrical Dust Precipitator
           FBF - Fluidized Bed Furnace
           HE -  Heal Exchanger
3.3  AUXILIARY FUEL AND  DESIGN  CAPACITY  OF  INCINERATOR
     As of March 1975, 59 plants of the  337 presently  operating  public owned
sewage treatment plants  (that is, 17.5%) have incinerating facilities. Of the total 94
incinerators,  74% were multiple furnace,  while fludized bed incinerator and rotary
kilns accounted for 8 to 9%.  Design capacity of each incinerator ranged from 5 tons
to 300 tons of wet cake per day.  All incinerators designed to handle more than 60t/
day were of the multiple furnace type. Auxiliary fuels were almost always A-heavy
oil, although some employed a digestion gas if it was available.
     Table 3.10 lists  the auxiliary fuels consumed by  36 incinerators during  1975.
Average consumptions ranges were:-
     standingtype: 142-3471/D.T
     dynamic type: 228- 561 d/D.T
     This wide range in fuel consumption is due to the varying moisture content the
dewatered cake, amount  and type of coagulating agent, and daily operating hours.
                                     148

-------
 Table 3.10  Auxiliary Fuel Consumption at 36  Incinerators (in 1975)


Process





(Thickening)
I
f
(Dewatering)

1
(Incineration)






(Thickening)
^--^^
s1^ ^^-^
(Dewatering) (Anaerobic
\Digestion)
1
\
(Dewatering)
/
/
(Incineration)


(Thickening) — (Anaerobic
Digestion)
L
(Incineration)— (Dewatering)
(Thickening) — (Aerobic
Digestion)
»
(Incineration)— (Dewatering)
(Thickening) — (Heat
Treatment)
t
(Incineration)* (Dewatering)

Dewater-
ing

Va
Va
Fp
Va
Va
Va
Va
Fp
Cf
Va
Va
Va
FP
Fp
Va
Va
Va
Va
Va
Va
Va
Va
Va
Va
Va
Va
Va
Va
Va
Va
Va
Va
Va

Va


Fp
Fp


Incinera-
tion

MHF
MHF
FBF
MHF
RK
MHF
MHF
FBF
FBF
MHF
FBF
FBF
MHF
MHF
MHF
MHF
MHF
MHF
MHF
MHF
MHF
MHF
MHF
MHF
MHF
MHF
MHF
MHF
MHF
MHF
RK
FBF
MHF

MHF


SGS
SGS

Design
Capacity
W.S.
Tons/Day
10
20
20
27
30
40
40
40
40
50
50
50
40
60
150
200
60
100
150
150
150
150
150
150
150
180
180
200
250
300
30
40
100

25


30
42.5

Yearly
Sludge Cake
W S.
Tons
2,400
3,498
2,900
3,630
7,212
9,834
6,708
5,776
2,994
20,741
4,980
3,955
6,392
9,033
38,722
50,370
12,659
16,003
50,450
42,812
33,363
39,181
38,303
37,790
59,956
51,606
57,408
67,240
77,331
90,765
3,197
6,952
10,032

4,119


10,972
16,230

Cake
ture

%
75.0
78.1
63.5
77.5
70.0
75.5
77.0
61.4
74.9
77.7
83.2
77.1
63.0
69.0
78.1
80.8
77.3
77.7
79.1
79.1
77.7
77.3
77.3
77.3
74.8
77.7
77.7
79.1
79.1
79.1
78.1
78.0
65.0

80.8


50.5
44.1

Consumed
Per Year

Kl
208
546
241
216
347
667
916
782
255
1,078
469
501
337
280
1,657
2-.9S5
674
1,169
1,712
1,382
1,528
1,660
1,632
1,340
2,202
1,728
2,046
2,347
2,259
3,636
263
716
978

329


(B) 1,256
(B) 1,369

Fuel/
Ton-D.S.

8/Ton-D.S.
347
713
228
264
160
277
594
351
339
233
561
551
142
84
195
309
235
328
164
156
205
187
188
156
146
150
160
168
141
193
376
468
279

399


(B)231
(B)151

Note: Va    Vacum Filtration            FBF -
     Fp    Filter Press                RK
     Cf    Centrifugation              SGS -
     MHF - Multiple Hearth Furnace       (Bj _
Fluidized Bed Furnace
Rotary Kilne
Step Grate Storker Incinerator
Included Heat Treatment
        Table 3.11  Capital Cost of Incinerator In N  S.T.P.
                                                       (in 1975)
Item

(1) Capital Costs for Civil Engg (x 103 ¥)
Building Costs
Equipment Costs
Total
80,692
603,409
684,101
(2) Capital Cost of Unit Processes
Sludge Cake Feeder
Frame of Furnace
Fuel Feeder
Air Pollution Controller
Ash Conveyer
Electric Power and Measurement
The Rest
Sub Total
69,517
145,986
6,952
88,982
6,952
139,034
145,986
603,409
                                    149

-------
     Fig. 3.2  show, relationship  between  incinerator  capacity (and hence  size of
incinerator) and the amount of fuel consumed.  The relationship between the heat
value of sewage sludge, and auxiliary fuel is now under investigation.
3.4  CASE STUDIES ON PERFORMANCE  OF  EMISSION  CONTROL FACILI-
     TIES
     In 1975, the JSWA began to investigate actual operating conditions and perfor-
mance of gas emission control equipment. Survey at 13 incinerators was completed
in 1975, and another 5 in 1976.  The results of survey on two cases of these inciner-
ators are described in  this paper.  The multiple furnace at  city N P.O.S.T.P.  was
equipped with after burner for deodoring  following the alkali washing for cleaning
stack gas. The multi-stage incinerator  employed in the A P.O.S.T.P of basin wide
sewerage system was equipped with an electric dust precipitator.
(1)  Multiple furnace at N P.O.S.T.P.
     The sewage treatment plant at city N has a capacity to process 63,000 m3/day
of sewage, servicing a population of about 100,000 people.  Activated sludge (step
aeration) method  are adopted for sewage treatment.  This plant received about
 18,000 m3 /day of industrial wastewater from brewery factories.
     The two which from  multiple furnaces  are capable of handling 30 to  50 wet
tons of dewatered sludge cake per  day. The exhaust emission from both furnaces is
integrated, and treated as shown in Fig. 3.3.  The results of the survey conducted in
December 1975, are  shown in Fig. 3.4.  Since there was no after-burner at that time,
auxiliary fuel consumption amounted to 27  1/T-WS.  Moisture content of the cake
entering the  incinerators was low, and the amounts handled were roughly  90% of
design capacity.  Consequently,  these incinerators operated  at relatively  high effi-
cienty rates,  requiring no more than 342  liter of auxiliary fuel per ton of dry solid.
The ratio of actual supplied air to the theoretical air requirement was 2.2, and incin-
erator operating temperature was at 826° C.
     Construction costs  have  been summarized  in Table 3.11.  And  maintenance
costs etc. are listed in Tables 3.12 & 3.13.

                      Table 3.12 Running Costs of N S.T.P.
(T) Term of Operating
@ Quantity of Dry Solids
® Personnel
® Fuel
® Electricity
® Water
@ Disposal of Ash
® Maintenance
®+®+®+®+@+®
1,857 hr.
2 730 ton - W.S. x (1 - 0.57) = 1,174 ton
0.632 ton - P.S./hr.
¥2,910,000/person
x 6x4/12 = ¥5,820,000
Heavy Oil (A) 122 k£
¥33.9/2 x 122 x 103 = ¥4,136,000
830,930 KWH
¥9/KWH x 830,930
167,120m3
¥13/m3 x 167,120
Ash 687 m3
¥3,330/m3 x 687 =
Oil Pipe etc. ¥100
= ¥7,478,370
= ¥2,172,560
¥2,287,710
,000
¥21,994,640
                                      150

-------
                                                      Fig. 3.2  Fuel Consumption of 33 Incinerators
    700
    600
                                                                                           a : With After Burning

                                                                                           b : Digestor Gas Included
    500
Q
 I
   400
    300
-2  200
u,
fr
    100
O : Multi Hearth Furnace

  : Fluid-bed Incinerator
x : Rotary Kilne
   Step Grate Storker Incinerator
                20        40         60        80
                                                        100                       150                       200

                                                            Design Capacity of Furnace (Ton/day)  Day: 24 Hours
                                                                          250
                                                                                                    300

-------
                        Table 3.13 Running Cost of
                                  Incinerator in IM S.T.P.

                                         (¥/Ton-D.S.) 1975

1
2
3
4
5
6
7

Item
Personal
(Attendance)
Fuel
Electricity
Water
Absorption Liquor
Disposal of Ash
Maintenancel)
Total
¥/Ton-D.S.
4,957
3,523
6,370
1,851
0
1,948
2,555
21,204
                         Note: 1) 2% of Capital Cost.


     The results of the survey conducted in August 1976 are summarized in Table
3.14, while the  operating conditions at the time  are shown in Table 3.15.  These
results show that although SO2 and dust concentration are below the standard limits
after the cooling tower, there is almost no change in NOx concentration. Odors were
tested according to the 3-point comparison "odor bag" method (used by the Tokyo
Metropolitan, Pollution  Control  Bureau),  employing both physiological  odor test,
and  analysis of offensive  odor substances.  In testing the degree of odor in the air
around the plant, a value of 1,400 degree was measured at the washing tower outlet.
Since the  height of the chimney was 20 m, it was expected that dispersion would
be sufficient to prevent  any offensive odor being noticeable at  ground level.  Emis-
sion  of offensive odor substances was no more than the standard values at boundary
line of the plant, and hence, was not considered to be likely to cause any problem.
                       Table 3.14  Performance Data in IM S.T.P.
                                                                   (Aug. 20, 1976)
Item
Feed Cake or Discharged Ash
Aux. Fuel
Composi-
tion Analy-
sis of Feed
Cake or
Discharged
Ash
Moisture
Free Moisture
Ash Content
Sulfur Content
Calorific Value
Unit
kg/h
fi/h
%
%
%
%
KCal/kg
Furnace No. 1
E: Cake
1,040
^^^
73.8
8.4
55.8
2.2
1,930
G: Ash
136
^^-^~
2.43
2.6
89.2
No Data
600
I : A Heavy Oil
^^^-^~~~~
52.5
_^^- — -~""~
^^^^
^^^^~~~~
^___- — ^"^
_— — -^~
Furnace No. 2
F: Cake
2,000
^^- — ""
63.3
8.4
53.0
1.8
2,150
H: Ash
368
^^-^'
0.09
1.4
94.7
No Data
<40
J : A Heavy Oil
^^-^~—~^
20.25
^_^-^--~~
^^-^~
___-— -^
^^---—^
_^~~~~'~~
                                     152

-------
Item
Gas Temperature
Dry Gas Flow Rate
Vapor Flow Rate
Wet Gas Flow Rate
Vapor Volume
Particulate Emission
S02
NOx
HC1
a,
Offensive Odor
Ammonia
Trimethylamine
Hydrogen Sulfide
Methyl Sulfide
Methylmercaptan
Methyldisulfide
Acetaldehyde
Styrene
0,
CO.
Unit
°C
Nm3/h
Nm3/h
Nm3/h
%
g/Nm3
ppm
ppm
Ppm
ppm
-
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
%
%
A
232
8,680
2,570
11,350
23.5
0.545
55.8
99.4
120.07
1.46
6,900
131.54
0.297
1.300
0.143
0.474
0.0005
<1.0
<0.001
12.1
6.7
B
28
9,170
370
9,540
3.9
0.138
11.1
85.1
24.84
1.46
No Data
10.80
0.123
0.436
0.052
0.242
0.0004
<1.0
<0.001
13.0
6.2
C
30
9,535
425
9,960
4.3
0.070
9.8
81.0
17.65
6.11
1,400
8.15
0.067
0.396
0.034
0.182
0.0002
<1.0
<0.001
13.5
4.3
D
68
11,910
585
12,495
4.7
0.034
4.3
71.8
10.38
2.24
No Data
3.83
0.028
0.235
0.017
0.114
0.0001
<1.0
<0.001
15.8
4.2
Standard
____- 	 — ~~~
^^-—-~~~~
________ — 	
________ — "~~~
______ 	 —
Less than 0.2
Less than 39
______ ~"~
_______---"
______ — — ""~~~
______----~~~
^____— ""
^___— - — ~~~
______ — ~~~~
______---'
^___^^"
_____ 	 — — ~"~~"
_____ 	 -^~~^~
^_____-^"
^___— ^"~~
____ — -^^
                           Fig. 3.3  Flow Diagram of Facility N
(Sludge Cake)
(!)
(Fuel)
n
(Sludge Ca



Multi Hearth
Furnace
(30 ton/day)
No. 1
L) c^
/^
7>
'


^
            Multi Hearth
              Furnace
            (50 ton/day)
              No. 2
Spray Scrubber
(Cooling Dust
Collecting)
Spray Scrubber    NaCIO
(Gas Absorption)
                                                                                  Actual Height H0 = 20 m
                                                                                  K Value = 1.75
                           (Ash)
                                              153

-------
Sludge
 Cake
        Furnace Feed Rate
        kg/h Wet Sludge
        Water Cbntent %
        Ash Content %
        Combustible
        Content
Lowes Calorific Value
(D.B.) kcal/kg
        C (D, B) %
        H (D, B) %
        N (D, B) %
        S(D,
                          1,843
                               67.1 -68.5
                                15.3-16.1
                       16.2-16.8
2360-2,500
                               23.0-23.2
                                3.5-3.8
                                3.1 -3.4
                                1.2-2.1
Ash.
Volume kg/h
Temperature °C
Ignition Loss Wt. %/Solid
Sulfur Weight %
Absolute Specific Weight
300
100
3.46
3.62
3.14
           Fig. 3.4  Results of Stack Gas Survey (N. S.T.P.)


                      1   Multiple Hearth Furnace  	50 TONS/day-W.S.

1975-12-12         2   Spray Scrubber (Cooling, Dust Collecting) ....  23,590 Nm3/hr

                      3.  Spray Scrubber (Gas Absorption)  	  16,720 Nm'/hr

Temperature   10 C    4.  Induced Draft Fan (Turbo)  	350 m3/min x 55 kW

Humidity - 46%       5.  Chimny 	  Height 20 m

                      6.  Axis Cooling Fan	75 m3/min X 7.5 kW

                      7.  Combustion Air Blower   	  50 m3/min x 11 kW

                      8.  Combustion Air Fan  	250 m3/min x 22 kW
                                                      30 t/D Furnace
                                                                          Treated Effluent

                                                                               I 95 m>
                                                                                                 Treated Effluent

                                                                                                        I 8 mj/h
                                                                                                         3)
Drain — -







Stack Gas
(Furnace Outlet)








Temperature °C
Vapar Volume %
Paniculate Emission
g/Nm3
SOx PPm
HC1 ppm
C12 ppm
NOxppm
col %
O2 %




290
36.6
1.12-1.46
115-123
92-99
1.2-1.3
58-62
9.4
9.2
                                                                                                               Spray
                                                                                                             Scrubber
                                                                                                                        ®

Stack
Gas
(Chimny)

•N. £
Flow Rate Mm3 /h
Temperature °C
Vapor Volume %
Paniculate Smission
g/Nm3
SOx ppm
HC1 ppm
C12 ppm
NOX ppm
CO2 %
02 %

D
13,000
22
5.1
0.16-0.18
2-12
20
2.2 - 2.7
10-19
4.0
16.0

                                                                                                                   Stack Gas
                                                                                                                   (Scrubber
                                                                                                                    Outlet)
                                                                                                                              Flow Rate Nm3/h
                                                                                                                              Temperature °C
                                                                                                                      Vapor Volume %
                                                                                                                              Paniculate
                                                                                                                              Emission  g/Nm3
                                                                                                                                   ppm
                                                                                                                                      Dust
                                                                                                                                   Draft Fan  J
                                                                                                                                                  10,200
                                                                                                                                              15
                                                                                                                                              2.2
                                                                                                                                            0.11
                                                                                                                                                    4~12
                                                                                                                                                    Sulfur Weight %/solid
                                                                                                                                                   Absolute Specific
                                                                                                                                                   Weight
                                                                                                                                                                         3.95
                                                                                                                                                                  2.63

-------
    The quantities of SOx, dust and NOx at measuring points per hour, have been
plotted in Fig. 3.5. Since it is not yet settled standard of concentrations of NOx
emissions for sewage sludge incinerator, the measured concentration were compared
with standards applied to control emission of NOx for boilers. Results showed that
NOx values exceeded this reference values.
                      Fig. 3.5 Flow Rate of Pollutants (Facility N)
       10
      E
      **-s
      0*
- 1.0
           - 0.5
                                                          (Facility N)
                                     NOX
                                                           NOX

                                                           SO2
                                                                      Dust*
                             Measuring Point
     The efficiency of the cooling tower in the processing of gas emissions was quite
 evident, but because of the low concentrations of pollutant in the gas phase, it was
 not clear whether  the cleaning device with chemicals was so effective in removing
 these pollutant.
 (2)  AP.O.S.T.P.
     This plant treates 43,000 m3 /day of sewage, and serves a population of 35,000
 people.  Activated  sludge  (step aeration) are adopted for treatment. The multiple
 furnace  can handle 40 wet tons/day. The operating condition  are listed in  Table
 3.16.  The  gas emission control equipment is shown in Fig. 3.6, and the results of
 analysis  of the emissions summarized in Table 3.17.
                                      155

-------
                   Table 3.15 Performance of Incinerator in N S.T.P.
Type
Design Capacity
Dewatering
Chemical Con-
ditioning
Running Time
(Hr/Day)
Keeping Warm Time
(Hr/Day)
Cake Moisture (%)
Incinerated Cake
(Ton/Day)
Aux. Fuel (A Heavy
Oil) (L/Day)
Kerosine (L/Day)
Electricity (kWH/
Day)
Absorption Liquor
(L/Day)
Water (M3/Day)
'Multiple Hearth
Furnace
Fu. No. 1 30 Ton/Day
Fu. No. 2 SO Ton/Day
Fp • Va
Ca (OH)2 + FeCl3
Fu. No. 1: 21
Fu. No. 2: 3
Fu. No. 1:3
Fu. No. 2: 21
Va (Fu. No. 1): 74
Fp (Fu. No. 2): 63
Fu. No. 1 22.40
Fu. No. 2 4.20
3,293
(Fu. No. 1 1,805
VFu. No. 2 1,488
-
4,872
NaOH (Concentration
48%)
208
NaCIO (Available
Chlorine 12%)
305
1,920
Remark











	
     The soot and dust level at the incinerator outlet was found to be 0.086 g/Nm3,
which is much lower than the 1 to 3 g/Nm3  which normally reported irr past data.
This result is attained by which characteristics of  applied sludge are stable and
making it  possible to operate continually with internal pressures (in the incinerator)
of -1 to -1.5 mmH2O. And this would reduce the level of dust which is found in
the gas emissions.  Such stable operating conditions reflect  careful and responsible
plant management.
     Similar to the dust levels, there was no problem with SO2 levels  either, since
levels inside the incinerator were already below the standard emission level. In order
to remove offensive odor, after burner fuel using kerosene. Emission gas was heated
to 750°C, and although there was a slight increase in SO2  level after the deodorizer
stage, analysis of offensive odor gave results which were even better than the perfor-
mance the plant at city N.
     NOx levels increased after the after burning.
     Operating costs of both incinerators are outlined  in Table 3.18.  The figures
indicate that  the  facilities in A P.O.S.T.P cost about  10 times as much as the facili-
ties in  N P.O.S.T.P. A major reason for the higher cost is the cost of kerosene used
in the after burning.
                                      156

-------
               Table 3.16 Performance of Incinerator in A S.T.P.
Type
Design Capacity
Dewatering
Chemical Condition-
ing
Running Time
(H/Day)
Keeping Warm Time
(HrADay)
Cake Moisture (%)
Incinerated Cake
(Ton/Day)
Aux. Fuel (A Heavy
Oil) (L/Day)
Kerosine (L/Day)
Electricity (kWH/
Day)
Absorption Liquor
(L/Day)
Water (M3/Day)
Multiple Hearth
Furnace
40 Ton/Day
Va
Ca (OH)2 + Fed 3
15
9
83
21.01
2,033
( Incineration 1,676
I Keeping Warm 357
3,795
2,044
NaOH (Concentration
48%) 50
i^liSSy11^
Remark








For After
Burner



                      Fig. 3.6 Flow Diagram of Facility A
                                                 ©
(Sludge Cake)
 9
Aih
©
(Fuel)
©


(40 ton/day)
Multi
Hearth
Furnace
r
©
71

r


NO
                       ©

Electrical
Dust
Precipltator
(Wet Type)




                                                                 ®-
                                                                  Actual Height H0 = 20 m
                                                                  K Value =1.17
                                      157

-------
Table 3.17 Performance Data in A S.T.P.
(Nov. 5,1976)
Item
Feed Cake or Discharged Ash
Aux. Fuel
Composi-
tion Analy-
sis of Feed
Cake or
Discharged
Ash
Moisture
Free Moisture
Ash Content
Sulfur Content
Calorific Value
Unit
kg/h
fi/h
%
%
%
%
KCal/kg
E: Cake
1,620
^^'
82.9
9.0
46.4
0.9
2680
F: Ash
123
^^"
0.5
1.1
95.4
1.5
50
G: A Heavy Oil
__-_—~~ """"
113
___——" "~
______ — -~~~"""'
______ ^
^—^-~~~~^
__—— ""^
H: Kerosine
____— """~~~"~"
270
^-~--~^~~^
^-—-"""^
r___— —""'
__-_^"~'
__-"""
Item
Gas Temperature
Dry Gas Flow Rate
Vapor Flow Rate
Wet Gas Flow Rate
Vapor Volume
Particulate Emission
SO.
NOx
HC1
a,
Offensive Odor
Ammonia
Trimethylamine
Hydrogen Sulfide
Methyl Sulfide
Methylmercaptan
Methyl Disulfide
Acetaldehyde
Styrene
o,
C02
Unit
°C
Nm3/h
Nm3/h
Nm3/h
%
g/Nm3
ppm
ppm
ppm
ppm
-
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
%
%
A
281
4,980
1,310
6,290
20.8
0.086
81.7
126
52.6
0.17
No Data
61.96
0.013
0.095
0.611
0.072
0.007
0.020
0.198
13.8
5.5
B
28
4,970
170
5,140
3.4
0.036
10.4
119
25.1
0.95
No Data
2.80
0.007
0.100
0.003
0.069
<0.001
0.006
0.194
13.9
5.4
C
22
5,190
140
5,330
2.6
0.008
9.5
112
24.1
1.04
No Data
2.09
0.006
0.068
0.003
0.049
<0.001
0.005
0.190
14.4
5.2
D
465
8,260
1,240
9,500
13.0
0.006
16.0
144
9.2
0.15
No Data
2.21
0.010
0.017
0.002
0.011
0
<0.001
0.091
10.5
7.8
Standard
^_-^-~~~'
^__— ---""""""
____- — —~~~~
^___- — —
____^ — — """"
Less than 0.2
Less than 84
	 "~~
____ 	 — """
_____ 	 -—"
_____ — — — ~"~
^^—- -~~~~~
____- — — ~~~
____—- — - -
	 -—- -~~""
____— — ' 	
______ 	
_____ 	 — ~~
^___ — -—•"""
______ 	
_____ 	 —-~
               158

-------
          Table 3.18 Cost Comparison of Incinerators in N & A S.T.P. (in 1976)
Item
Fuel
Electricity
Water
Absorption Liquor
Fuel (Afterburning)
Total
Costs, V/Ton-W.S.
Costs, ¥/Nm3-W.G.
N S.T.P.
2,474 ¥/h
(72.758/h x 34 ¥/B)
l,560¥/h
(156 kWH x 10 ¥/kWH)
Emission Control 700 ¥/h
720 ¥/h
(80 m3/h x 9 ¥/m3)
108 ¥/h
(NaOH 2.4 fi/h x 45 ¥/£)
875 ¥/h
(NaOC1502/hxl7.5¥/8)
^^^^^
5,737 ¥/h
1,887
0.2
A S.T.P.
3,842 ¥/h
1132/hx34¥/e)
l,470¥/h
(147 kWH x 10 ¥/kWH)
Emission Control 960 ¥/h
450 ¥/h
(50 m3/h x 9 ¥/m3)
153, ¥/h
(NaOH 3. 4 2/h x 45 ¥/C)
10,560 ¥/h
(264C/h x 40 ¥/8)
16,475 ¥/h
10,170
1.9
Remark
34¥/fi
(A Heavy Oil)
10¥/kWH
9¥/m3
(Treated Effluent)
NaOH 45 ¥/e
NaOCl 17.5 ¥/6
40¥/C
(Kerosine)



3.5  TENTATIVE  PROPOSAL  FOR STANDARD  EMISSION  CONTROL SYS-
     TEM IN SLUDGE  INCINERATORS
     When considering a standard emission control system of gas emissions, it is very
difficult to estimate emission conditions quantitatively because  of the considerable
degree of variation in  both amount and composition of the exhaust gases being
generated.  Emission standard also  vary according to location.  Summary of the
presently  available  information  on the fludized bed incinerator,  and  the more
common multiple furnaces, are presented in Fig. 3.7 and Table 3.19. In Fig. 3.7, A
refers to standard  control systems,  while B refers  to cases subject to much more
stringent controls.
     The temperature of the emission gas at the  incinerator  outlet is  normally
around 150 to 300°C, so there is little advantage in heat recovery. Because of the 1
to 3 g/Nm3 dust levels at outlet of furnace, a dust removal is incorporated in the
cooling facility, thus alleviating the load of the following washing tower with chemi-
cal or electric precipitator.
                                     159

-------
                        Fig. 3.7  Flow Rate of Pollutants
                                                               (Facility A)
     10
   E
   :z







X
3
Q
0 5

5.
"E
r*
o

























^_

^
V
A











*••••


\
\
V
\













\















X.
"


$
/
,
'
/
/





^

1
1
1
1
1









^•-*

,













































                                          ©         ©
                                                                          NOX
                                                                          Dust
                                                                          S02
                          Measuring Point
                   Fig. 3.8 Basic System for Emission Control
Multiple Hearth Furnace
Furnace ^ —
«• Cooling \-» GaS(A,b,?'y
)tion\_L Minutely Dust N. ^
) | Collector T~^
Deodorization N
Fluidized Bed Furnace ~l
Furnace \— •-
Recovery \ Dry Dust \ __
of Heat p^ Collector j~*

Cooling \_.» Gas Absorpt\
PT ion (Alkali)
y. Minutely DusK
Collector

                                        160

-------
  Table 3.19 Standard Requirement of Emission Control Equipment for Two Different Furnaces

Heat Recovery
Dry Type Dust
Collector
Cooling
Absorption
Minutely Dust
Collection
De-odorization
Multiple Hearth Furnace
Stack gas temperature ranges from 150~
300°C. It is too low to recover the heat.
Ash is disposed from bottom pit. Dust
concentration in stack gas is as low as 1~
3 g/N-m3 and, no dust removal is required,
unless wet scrubber follow.
Fluidized Bed Furnace
Stack gas temperature ranges from 800 to
900°C. Excess heat above 300°C can be
recovered.
All ash is included in stack gas. Dry type
dust collector is required to reduce load for
wet type scrubber.
Cooling is required as pretreatment in advance to absorption or minute dust collection.
SOx, HC1 and C12 should be removed through absorption process.
Fine particle material should be removed to attain such a low concentration as 0.05 g/N-m3
Deodoring is required.
Operation temperature is high enough to
decompose all smelling material. No de-
odoring equipment is required.
     In the next stage, the absorption and removal of SOx, HC1, chlorine (C12) and
 other acidic gases conducted by washing with chemical. The SOx level at the incin-
 erator outlet is normally 20 to 500 ppm. Not all of the sulfur compounds in the
 dewatered cake is transfered into the emission gas, some 50 to  80% remains in the
 ash. This is because of the presence on non-combustible sulfates (like CaSO4 and
 BaSO4) etc. in the  dewatered cake, and because of the likely reaction between SOx
 (produced during incineration) and alkaline components in the ash. Previous surveys
 found that water washing removed large proportions of SOx, but to meet stringent
 emission  standard,  caustic soda (NaOH)  washing needs to adopt. But since dust
 still remain in the gas at this stage, and higher pH levels, although reducing the SOx
 level in the emission induce, the caustic soda to react with the CO2 in the gas  emis-
 sion, the  pH is regulated to about 7  to  8, employing a recycling method.  Excessive
 consumption of NaOH, and blockage of  filter due  to the dust, are  thus avoided.
 HC1 and  C12 are also removed in the same process,  HC1  being sufficiently reduced
 by water  or alkaline solution washings, and C12  absorbed by  the  alkaline solution.
     Most of the dust is removed by cooling and absorption, these processes reduc-
 ing the concentration down to about 0.2 to 0.5 g/Nm3.  However, these processes
 are not very efficient in removing the very fine particles which diameter are less than
 10/;.  Low pressure difference mechanical  dust collector (Cyclon) are  not  very
efficient either, but  fine dust collector (electric dust precipitator etc.) can bring the
level down to about  0.05 g/Nm3.
     The dilution ratios in odor measurements under normal conditions varied  con-
siderably from  70 to  20,000. Although after burning is used to remove offensive
odor, this  process  consumes large amounts  of fuel.  Therefore  heat recovery is
necessary.   Chemical washings with acid and alkalis are also reasonably efficient in
reducing offensive odor, but they cannot achieve complete removal.
     Concentration of nitrogen oxides (NOx) is normally about 30 to 150 ppm, and
this is considered to be due to "fuel NOx" rather than "thermal NOx".  The amount
                                      161

-------
of nitrogen in the volatile matter of sewage sludge is 4 to 8% (by weight), 1 to 4% of
which forms NOx.  At the moment, however, there is no  NOx emission control
standards for sewage sludge incineration.
     The emission gas temperature at the incinerator outlet in fluidized bed inciner-
ators is 800 to 900°C, thus possible heat recovery up to about 300 to 350°C. How-
ever, since all the incineration ash is theoretically carried by the emission gas, special
care must be exerted to prevent blockage in the heat exchanger.
     The quantity  of dust varies considerably according  to the  condition of the
incinerated sewage  sludge (ash contents), but normal concentration is from 30 to
160 g/Nm3. Therefore, a dry-type dust collection is adopted (mechanical scrubber)
after the heat exchanger,  and this in turn is followed by a wet washing to further
reduce the dust.
     Furthermore,  the area of contact between  the sewage  sludge and  gas in the
fludiged bed incinerator is relatively large, so when the internal  temperature is
maintained at 80o  to 900°C, and lime used as a coagulant, a certain amount of reac-
tion between the lime and SOx,  HC1,  and  C12 can be expected. The source and
mechanism of the generation process of pollutants in gas is essentially the same as in
the multiple  furnace, so, the  emission control system are composed with dry type
dust collection.
     By combustion and decomposition of offensive odor substances in the inciner-
ator, there are no odor substances left in the emission gas, so no deodoring devices
are required.
     It has been believed that generation of NOx by fluidized bed incinerator had
been higher  than in multiple  furnace, but the  results of this survey show that this
was not exact. There is no emission standard of NOx which is applicable to sludge
combustion incinerator at the present.
                                    162

-------
        CHAPTER 4.  STUDIES ON SEWAGE SLUDGE  PYROLYSIS
4.1   Introduction	164
4.2   Pilot Plants and Sludge Cakes Used in Experiment	165
4.3   Basic Study on Drying-Pyrolysis Process 	169
  4.3.1   Experiments of Drying for Dewatered Cake Using by Indirect
         Steam Dryer	169
  4.3.2   Experiment on Pyrolysis of Dried Cakes  	171
  4.3.3   Products of Dried Cake Pyrolysis	179
4.4   Practical Study on Drying-Pyrolysis Process	182
  4.4.1   Experiment on Drying for Dewatered Cakes Using by Indirect
         Steam Dryer	182
  4.4.2   Experiment on Pyrolysis 	182
  4.4.3   Products of Dried Cake Pyrolysis	   186
  4.4.4   Comparison of Drying-Pyrolysis Process, Direct Pyrolysis Process
         and Indirect Pyrolysis Process  	190
4.5   Summary	192
                                   163

-------
4.    STUDIES ON SEWAGE SLUDGE  PYROLYSIS
4.1   INTRODUCTION
     Sewage  treatment plants in large municipalities and their environs are being
subjected to increasing restrictions on the acquisition of land for sewage sludge land-
fill in Japan.  For this reason, there are found many cases where sludge is incinerated
at sewage treatment plant sites  for the most  effective use of the land acquired to
their sludge filling.
     However, the incineration of sewage sludge has been faced with several  severe
problems, which require an early settlement.
     First, the more  severe  environmental quality  standard  on air pollution has
established it indispensable for sewage treatment plants to set up incidental facilities
of incinerators, such  as electric  precipitators,  to prevent pollution  causing by the
exhaust  gas.  The construction and operation of such facilities require additional
expenses.
     Second,  it  has  also become  necessary  to  set up incidental facilities  of
incinerators for  offensive odor control, such as exhaust gas combustion  (after-
burning) facilities,  because of the strong  demand  from residents  for preventing
offensive odor arising from sludge incineration.  The construction and operation of
such facilities also require  additional expenses.
     Third, it has been found that lime  used as a conditioner  of sludge dewatering,
and trivalent chromium compounds contained in municipal sewage sludge show a
chemical reaction in the furnace at the time  of incineration.  The trivalent chromium
compounds in sludge  are oxidized into hexavalent chromium compounds which are
soluble in water.  Therefore,  the filling of land with incinerated ash has a danger of
causing   the pollution of surface water and underground water   by  hexavalent
chromium compounds. For the prevention of such  pollution, it  requires much
expense for landfill.
     Fourth, the operational cost for sludge  incineration — fuel cost and electric
power charge — has been increasing sharply every year due to the spirals in the prices
of oil products in addition to the increased use of fuel  and electric power for in-
cidental  facilities of incinerators. Sewage treatment plants in some areas are obliged
to use better quality fuel than before to establish  the environmental quality standard
on air pollution.
     Under these circumstances, it is expected  to  be  more advantageous, for the
following reasons, to reduce the  volume of solid residue (ash)  by pyrolysis than to
incinerate it.
i)    In pyrolysis, the  furnace is operated naturally at the lower combustion air ratio
than in  incineration.  Accordingly, the amount  of  exhaust gas is reduced and the
construction cost and  the operation cost (fuel cost  and electric power charges) of
the incidental facilities for the  control of both air pollution and  offensive odor

                                      164

-------
might be able to cut down.
ii)   Since the inside of the pyrolysis furnace is maintained in a reducing condition
or in a condition close to it, there is little possibility of the trivalent chromium com-
pounds in sewage sludge being oxidized into haxavalent chromium compounds.
iii)  Pyrolysis might require more fuel in the furnace itself than incineration. How-
ever, the amount of fuel used in the furnace might be able to reduce, if combustible
gas obtained by pyrolysis is burned in the combustion chamber and steam generated
in boiler is used for preliminary drying of sludge.  Therefore, there is expected a
strong possibility that fuel consumption for the pyrolysis as a whole system could be
smaller than that for incineration.
     So far, multi-hearth furnace have dominantly been used for sewage sludge in-
cinerations at sewage  treatment plants in Japan.  Therefore, there are many skillful
engineers and  operators for design  and  operation  of such  furnaces.  If the multi-
hearth furnaces now in use are rebuilt for pyrolysis of sewage sludge, it will be
expected of great benefit to the social and economical aspects in the nation.
     For these reasons, the Ministry  of Construction decided on the disbursement of
the public  works  technology and development subsidy for fiscal  1976 to conduct
practical study work on pyrolysis  by applications of multi-hearth furnace.  The
ministry offered  for public  subscription to  interesting organizations and, after
screening application documents, decided  to  give the subsidy  to a privated firm
(NGK  Insulators, Ltd.,  Nagoya).  The company,  which has experiences of basic
study works in the past (1), proposed to conduct additional basic study and new
practical study at pilot plants. The  Ministry of Construction organized a discussion
group to have  the views of users reflected on  the study.  The group is made some
engineers of Kyoto  University, Osaka Prefecture, Kyoto City, Hyogo Prefecture  and
the Japan Sewage Works Agency as well as the Ministry of Construction.
     The Practical study was not completed at the time of this reporting.  However,
a series  of experiments were concluded and their results were compiled. They were
conducted at a pilot plant established in the Kawamata Sewage Treatment Plant site
of Osaka Prefecture, using raw dewatered  sludge carried  from  the Toba Sewage
Treatment  Plant in  Kyoto.  At present,  the project  is being examined from  the
economic viewpoint, and conditions for the  designing  of facility  to be put to
practical use are being discussed.
     More experiments  are to be conducted at  the pilot plant, using heat-treated
sludge taken from a sewage treatment plant  in Osaka Prefecture and raw dewatered
sludge separated from waste at  a chromic tanning pre-treatment facility in Hyogo
Prefecture.
4.2   PILOT PLANTS AND  SLUDGE CAKES  USED IN EXPERIMENTS
     Basic study and practical study were conducted separately at  different pilot
plants.  Used in the basic experiments was a pilot  plant with a capacity to treat 2
tons of sludge  cakes per day with  the water content of 75%   The flow chart of
this pilot plant is shown in Fig. 4.1.  The  Figure shows the sampling points for
solid (Si - Ss), liquid (Li - Ls) and gas (Gi - Gs) in  addition to various sorts
of machinery and instrumentation constituting the pilot plant.
                                     165

-------
                   Fig. 4.1 Pilot Plant Flow Chart Used for Basic Study
                                                                             Fuel Supply

                                                                             Industrial
                                                                             Water Supply
Explanation
©
©
CD
©
©

Cake
feeder
Paddle
dryer
Single-
hearth
furnace
De-
humidtfer
Blower
for dryer

©
©
©
©
©

Burner
Combustion
chamber
Blower for
partial
combustion
Blower for
exhaust gas
Scrubber
stuck

©
©
©
©
©

Blower for
combustion
chamber
Blower for
circulated
gas
Blower for
burner
Fuel tank
Fuel pump

©
©
@
@
©

Heat
source
chamber
Nitrogen
gas supply
Water
softening
installation
Soft water
storage
tank
Water
supply
pump
®
®
©
®
©

Exhaust gas
boiler
Condensed
water tank
Condensed
water
circulator
Solid residue
cooling tank
and container
Screw type
feeder

®
©
(28)
®
@*

Conveyer
Hoist
Cake
container
Double
sealing
damper
Dried
cake
container
Sampling point
Sampling point of solids
 S,  Cake of dryer inlet
 S2  Cake of dryer outlet
 S3  Residue of pyrolysis
Sampling point of liquids
L,  Supplied water
L2  Wastewater of dehumidifer
L,  Wastewater of scrubber
Sampling point of gases
G,  Outlet of dryer
Gj  Outlet of pyrolysis furnace
G3  Inlet of combustion chamber
G4  Outlet of exhaust gas boiler
G,  Outlet of scrubber
     The flow chart of the pilot plant used for practical study is shown in Fig. 4.2.
It is different from the pilot plant for the basic study in the following points.
i)    The indirect steam  dryer of paddle type was changed from  a two-shaft dryer
to a four-shaft dryer.
ii)   The plant was designed  so that dewatered sludge cakes could also be thrown
into the furnace  directly without passing through the indirect steam dryer of paddle
type.
iii)  The single-hearth furnace was changed to a four-hearth furnace.
iv)  The heat  source  chamber  was  directly  attached to the pyrolysis furnace  in
                                         166

-------
                  Fig. 4.2 Pilot Plant Flow Chart Used for Practical Study
                                                                          Water Supply
                                                                             Secondary
                                                                      ~j—I    Effluent Supply
 Explanation
©
@
0)
0
©

©




©
®
Cake container
Hoist
Cake feeder
Dried cake
feeder
No. 1 cake
conveyer
No. 2 cake
conveyer
No. 3 cake
conveyer
No. 1 screw
conveyer
No. 2 screw
conveyer
Paddle dryer
©
©
®
@
(15)
V^-y
©
(rf>
(LJ)


©
®
Sieve machine
Dried cake con-
veyer
Dried cake con-
tainer
Roller conveyer
Pyrolysis fur-
nace
Ignition burner
for partial com-
bustion
Heat source
chamber
Heat source
burner
Blower for
burner
Propane gas
supply
®
©
©
@
(25)
^y
©


6^1
^5
©
©
Fuel tank
Fuel pump
Compressor
Quenching
tank
Residue carry
conveyer
Residue con-
tainer
Roller con-
veyer
Blower for
pyrolysis
No. 3 scrubber
No. 2 blower
for exhaust gas
©
©
©
(34)
(P)
"Cx
(36)
(T7)
^
/^
Vi3'
(39)
®
No. 1 scrubber
Blower for
dryer
Combustion
chamber
Burner fpr
combustion
chamber
Blower fpr
combustion
chamber
Boiler
Condensed
water tank
Condensed
water circulator
Soft water
tank
Water soften-
ing installation
©
©
©
@
(45)
VJx
@
(4^
($1)




Water supply
tank
No. 2 water
supply pump
No. 1 blower
for exhaust gas
Blower for cir-
culation
No. 2 scrubber

Water storage
tank
No. 1 water
supply pump




Sampling point
Sampling point of solids
 S,  Cake of dryer inlet
 Sa  Cake of dryer outlet
 S3  Residue of pyrolysis furnace
Sampling point of liquids
 L,  Supplied water
 L2  Wastewater of No. 1 scrubber
 L3  Wastewater of No. 2 scrubber
Sampling point of gases
G,  Outlet of dryer
G2  Outlet of heat source chamber
G3  Outlet of pyrolysis furnace
G4  Outlet of combustion chamber
G,  Outlet of scrubber
order to reduce heat loss.
v)   The pilot plant was designed so that experiments could be conducted with the
drying-pyrolysis process as a continuous system.
vi)  The system  to deal with solid residue discharged from the furnace was changed
so that it would drop into water to be scooped up automatically.
vii)  A propane  gas burner was attached to each hearth of the  pyrolysis furnace as a
supplemental heat source.
                                          167

-------
viii)  The combustion chamber was designed to  allow  the  automatic control  of
oxygen concentration in it.
     Table 4.1 shows the details of main machinery and instrumentation of the pilot
plants both for basic study and for practical study.

                          Table 4.1 Details of Pilot Plant
Name



Indirect
Steam
Dryer




Pyrolysis
Furnace



Heat
Source
Chamber



Com-
bustion
Chamber




Exhaust
Gas
Boiler



Items
Type
Numbers of Shaft
Areas of Total Heat Transfer

Numbers of Screw per Shaft
Dimension (mm)
Revolution of Shaft
Counter of Drain
Method of Heating
Type
Total Bed Areas

Dimension (mm)
Attachment
Capacity of Burner
Dimension (mm)
Duct Length to Pyrolysis
Furnace
Attachment

Type
Capacity of Burner
Volume of Chamber
Dimension (mm)
Type
Areas of Total Heat Transfer
Production of Steam
Max. Pressure of Steam
Drain Storage Tank
Drain Circulator
Soft Water Tank
Softening Water Installation
Water Supply Pump
Pilot Plant for Basic Study
Paddle Type
2
8.1m2

16
560 Wx 850 H x 2,800 L
12rpm
Volumetric
Inner Heating
Single-Hearth Furnace
2.1 m2

1,800 ID x 2,200 OD x 1,000 H
-
90,000 kcal/hr
400IDx8000Dx 1.500L
4 m

Circulating Gas Flow Control
Unit
Direct Combustion
90,000 kcal/hr
0.2m3
400 ID x 800 OD x 1.500L
Breeching 3 Pass
7.7m2
100kg/hr
7 kg/cm2 • G
0.25 m3
0.03 m3
0.2 m3
200 kg/hr
6602/hrx80mH
Pilot Plant for Practical Study
Paddle Type
4
10.1m2

12
1,097 Wx 1.125H x 2,300 L
15 rpm
Volumetric
Inner Heating
4-Hearth Furnace
1.63m2

900 ID x l,3600Dx 2,096 H
Gas Burner 5,000 kcal/hr x 3
80,000 kcal/hr
250 ID x 760ODx720L
0.5 m

Circulating Gas Flow Control
Unit
Direct Combustion
150,000 kcal/hr
0.25 m3
400 ID x 800 ODx 2,412 L
Breeching 3 Pass
5.8m2
100 kg/hr
9.5 kg/cm* -G
0.33m3
0.038m3
0.2m3
200 kg/hr
2002/hrx 10 kg/cm2
     The dewatered  cakes used in the experiments were taken from the vacuum
filter room of the Toba Sewage Treatment Plant in Kyoto City. Table 4.2 shows the
analytical results  of dewatered cake samples.  The compositions of ignition loss of
the dewatered cake samples are shown in Table 4.3. The analytical  results of the
perfect ash in the dewatered cake samples are also shown in Table 4.4.
                                    168

-------
4.3  BASIC STUDY ON  DRYING-PYROLYSIS PROCESS
4.3.1   EXPERIMENTS OF DRYING  FOR DEWATERED CAKE  USING BY
       INDIRECT STEAM DRYER
     The dryer used in the experiments is an indirect steam dryer of paddle type
shown in Fig. 4.3. Steam used  for the dryer is supplied by the exhaust gas boiler
(21).  That is, after the pressure  of steam is adjusted so that steam temperature will
reach a fixed point, the steam is  supplied to the jacket, screw and shaft of the dryer,
as shown in Fig. 4.3. And, the steam is condensed into moisture after being used for
drying dewatered  cakes.  The moisture was returned to the exhaust gas boiler after
volumetric measurement.  In the experiments, the Overall Heat Transfer Coefficient
(U) was found by  Equation-( 1).
     U = Q/A-At (Kcal/m2 -hr^C)	   (1)
Where,   At  = ts - tc
         Q = Ys x Md
     Q     Heat Transfer Capacity (Kcal/hr)
     A     Total Heat Transfer  Area of the Dryer (m2)
     ts     Temperature  of Supplied Steam (°C)
     tc     Average Temperature of Dewatered Cakes in the Dryer (°C)
     Md    Amount of Condensed Moisture Generated (kg/hr)
     Ys    Condensed Heat of Supplied Steam (Kcal/kg)
     Some examples of relationship between the moisture content (%) of raw sludge
cakes at the inlet of the dryer and the Overall Heat Transfer Coefficient (U) is shown
in Fig. 4.4.  There was no major difference in drying efficiency between raw sludge
and digested sludge, and their Overall Heat Transfer Coefficients (U) are within the
range of 70 ~ 100 Kcal/m2-hr-°C.  Similar experiments on  heat-treated sludge
showed that its Overall Heat Transfer Coefficient (U) was 215 Kcal/m2 -hr-°C.  This
is presumably because the fullness ratio of heat-treated sludge in the dryer is higher
than  that of raw  sludge or digested sludge and because moisture contents in de-
watered cakes exists in different conditions.
         Fig. 4.3 Schematic Drawing of the Indirect Steam Dryer of Paddle Type
                Used for Pre-Treatment of Sludge Cake
                     Dewatered sludge
                     cake              Screw
              Air
                                                       —•• Exhaust gas
                                                      c
                                    169

-------
                 Fig. 4.4 Relationship between Moisture Content and
                         Overall Heat Transfer Coefficient
    250
   200
   150
s
o  100
    50  -
           100:250
       40
                    50
60
                                                   100:0
                               i   Dried and wet mixed
                                  raw sludge cake


                               o   Raw Sludge cake
                               X   Digested sludge cake
                               A  Heat treated sludge cake

                               D  Tannery waste sludge cake
                                                                    Mixture ratio
                                                                    Wet cake : Dried cake
70            80

        Moisture content of cake (%)
                Table 4.2  Analytical Result of Dewatered Cake Samples
                                                                                   (Dry Base)

Date
of
Sam-
pling
Aug.
9
Aug.
30
Date
of
Sam-
pling
Aug.
9
Aug.
30
Mois-
ture
Con-
tent
(%)
74.6
75.6
Pb

(ppm)
100
175

Igni-
tion

(%)
55.0
49.3
As

(ppm)

4.4
Vola-
tile
Con-
tent
(%)
53.2
52.0
Total
Cr

(Ppm)
200
170
Gross
Calo-
rific
Value
(kcal/
kg-DS)
2,470
1,800
Cr+6

(ppm)
-
7.3

C

(%)
24.8
18.0

H

(%)
4.1
4.0
Zn

(ppm)
2,600
1,450

N

(%)
2.8
2.9
Cu

(ppm)
-
360

S

(%)
0.71
0.51
Fe

(ppm)
-
6.21

0

(%)
25.2
30
A1303

(%)
4.8
2.17

Cl

(%)
-
1.0
CaO

(%)
14.08
26.3

CN

(ppm)
-
4
MgO

(%)
-
0.77

NH3

(ppm)
-
220
Na3O

(%)
-
0.18

Hg

(ppm)
-
1.7
K,0

(%)
0.49
-

Cd

(ppm)
-
7.2
SO,

(%)
13.88
7.98
                                           170

-------
                   Table 4.3 Compositions of Ignition Loss in Samples

Date of
Sampling

Aug. 9
Aug. 30
Gross
Calorific
Value
(kcal/kg-DS)
4,491
3,651

C

(%)
45.1
36.5

H

(%)
7.5
8.1

N

(%)
5.1
5.9

S

(%)
1.3
1.0

0

(%)
45.8
60.9

Cl

(%)
-
2.4

CN

(ppm)
-
8.1

NH3

(ppm)
—
446
                 Table 4.4 Analytical Result of Perfect Ash in Samples
Date of
Sampling
Aug. 9
Aug. 30
Total
Cr
(T-Cr)
(ppm)
360
355
Cr+6
(ppm)
82
190
Cr+6/T-Cr
(%)
17.2
53.5
Soluble
Cr+6
(S-Cr+6)
(mg/8)
4.5
0.36
Soluble Rate of Cr+6
(%)
S-Cr+6
T-Cr+6
(%)
72.6
1.9
S-Cr+6
T-Cr
(%)
22.5
1.0
CaO
(%)
31.3
51.9
4.3.2  EXPERIMENTS  ON  PYROLYSIS OF DRIED CAKES
     In the experiments, dried cakes by the indirect steam dryer were stored in the
feeder at first and then a constant amount of them was fed into the single-hearth
furnace(s) by a screw feeder (2^) shown in Fig. 4.1. The  heat sources to the furnace
were hot blast from the  hot  source chamber and heat of partial combustion propor-
tionate to the ratio of fixed combustion air to sludge feed to furnace.  Gas from the
outlet of the furnace was sent to the combustion chamber(v), where combustibles
was burned and such offensive odor components, HCN and NH3 were decomposed,
and then the heat was recovered as steam by  the waste heat boiler(2J). Part of the
exhaust gas  in the boiler was circulated to adjust hot blast in which oxygen  con-
centration is almost zero.
     The remainder of the  waste gas was released into the air  after being  sent
through the  scrubber (To). The solid residue taken out of the pyrolysis furnace was
cooled indirectly without contact with the air.
     The conditions of these experiments were as follows.
i)    Ratio of theoretical amount  of combustion air to  actual amount of combus-
tion air of fed sludge: 0 ~ 2.0
ii)   Temperature in pyrolysis furnace:  600 ~ 900°C.
iii)   Sludge feed loading into furnace: 10 ~ 40 kg- DS/m2 • hr
iv)   Estimated detention time of sludge in furnace: 15 ~ 60 min.
v)    Condition of decomposition of exhaust gas
       Temperature in combustion chamber:  900 ~ 1,100°C
       Oxygen concentration:  0 ~ 3%
     The ratio  of theoretical  amount  of combustion  air  to  actual amount of
combustion  air of fed  sludge (ratio of amount of combustion air)  was adjusted
by a partial combustion blower.
                                    171

-------
     In  order to evaluate the degree of decomposition of combustibles, the igni-
tion loss of solid residue was measured and the decomposition rate of combustibles
was estimated by Equation (2).
     Decomposition Rate of Combustibles (^
                 Ignition Loss of Solid Residue (%)
              100 - Ignition Loss of Solid Residue (ty
                       _._    Ignition Loss of Fed Cake(%)
                       '  100 - Ignition Loss of Fed Cake (%)

a.   Ratio of Theoretical Amount of Combustion Air to Actual Amount of
     Combustion Air of Fed Sludge (Ratio of Amount of Combustion Air)
     Three sorts of data were collected to investigate this problem. The first con-
cerned the changes in the form of chromium  in solid residue according to the ratio
of amount of combustion air, which are shown in Fig. 4.5 and Fig. 4.6.  Fig. 4.5
shows the results of experiments on raw sludge at the Toba Sewage Treatment Plant.
Fig.  4.6  shows, for comparison,  the  results of experiments on  sludge of chromium
tanneries' waste which contained a large amount of trivalent chromium compounds.
The  second  data concerned the  relationship between the ratio of amount of com-
bustion air and both ignition loss of solid residue and the decomposition rate for
combustibles in sludge.  It is shown in Fig. 4.7.
     Fig. 4.5 and Fig. 4.6 show that, when the ratio of amount of combustion air is
below 1.0, the ratio of Cr+6/T-Cr in  solid residue is smaller than that of Cr+6/T-Cr
in dewatered cake  and that the lower the ratio of amount of combustion air, the
higher is the decrease rate. Elution of hexavalent chromium from the solid residue
was  not  observed.  If the ratio of amount of combustion air is below 1.0, oxygen
supplied  to the pyrolysis furnace is consumed by the combustion of inflammable gas
generated by pyrolysis and the combustion of carbon retained in solid residue, with-
out causing the oxidization of new trivalent chromium compounds. In case the ratio
of amount of combustion air is still lower, a part of the hexavalent chromium com-
pounds already  contained in sludge is reduced in the pyrolysis  furnace by reducing
gas, such as hydrogen and carbon oxide gases generated by pyrolysis.
     In contrast, the ratio of Cr+6/T-Cr were  fairly increased in solid residues when
dewatered cake was  dried and  incinerated completely in an electric furnace and
when it was incinerated at the furnace of pilot plant with the ratio of amount of
combustion air  set at 2.0, comparing to the  ratio of Cr+6/T-Cr in dewatered cake
itself.  When the amount of the hexavalent chromium compounds  eluted was
measured by the Solubility Test Method as provided by the Ministerial Ordinance of
the Prime Minister's Office, it has been found at some plants that the soluble con-
centrations of hexavalent chromium in  solid  residue exceed the limit of 1.5 rng/C
sometimes, when dewatered cakes were incinerated in existing furnaces.  This means
that  a high ratio of amount of  combustion air, such as about 2.0, promotes the
oxidization reaction of trivalent  chromium compounds and a part of them changes
hexavalent chromium compounds.
     According  to Fig. 4.7,  the  higher the ratio of amount of combustion air, the
further promoted is the decomposition of combustibles in sludge. This means that

                                    172

-------
a high ratio of amount of combustion air promotes the combustion of carbon re-
maining in solid residue.
     From the viewpoint of preventing the oxidization of trivalent chromium com-
pounds in sludge, the appropriate ratio of amount of combustion air is considered to
be around 0.5 ~ 0.7.


              Fig. 4.5 Behaviour of Chromium in Each Solid Residue
                      (Raw Sewage Sludge in Toba Sewage Treatment Plant)
     100
 B
u
o
 c
 o
U
      10
              (Oxygen concentrations
               at outlet of furnace are
               shown in parenthesis)
                                         (0.7%)
                 (0.5%)
                                                     Cr
                                                       +6
             ^
               \
                \
                 \
      — o—
       (ND)


                                             /

                                                                  (4.5 mg/fi)
                                                                      D
                                                              XX(0.87mg/8)
                 (ND)
                    (Soluble concentration of
                     hexavalent chromium in
                     solid residue are shwon in
                     parenthesis)
                                               _L
                                                                             10
                                                       
-------
                   Fig. 4.6  Behaviour of Chromium in Each Solid Residue
                            (Raw Sludge of Tanneries Waste)
 10,000
  1,000
bfl
u
<*-<
o
a
o
U
                                                                           °"(124mg/fi)
                  (Oxygen concentrations at
                  outlet of furnace are
                  shown in parenthesis)
           (0.27)
    100
     10
                                                                                      (l,440mg/B)
10
                                                      (Soluble concentrations of
                                                       hexavalent chromium in
                                                       solid residue are shown in
                                                       parenthesis)
            Dried   0    0.2   0.4    0.6   0.8    1.0   1.2   1.4   1.6   1.8   2.0   Perfect
            cake                                                                   Ash

                                 Ratio of amount of combustion ail
                                                                                               V
                                                                                           0.1
                                                                                           0.01
                                             174

-------
               Fig. 4.7 Variation of Both Ignition Loss of Solid Residue
                      and Decomposition Rate of Combustible to Ratio
                      of Amount of Combustion Air



g
£
e
0
1
0
ex
1
•§
3
C
O
'H



100
90
80
70
60


50


40
30


20
10
n
. 	
-_.——• * ""— "~ Decomposition rate of co


Pyrolyzing temp.
Feed loading of c

-



-



•• 	 — ».. Ignition loss of solid r
1 1 1 1 , , , | -
                      0.4  0.6   0.8  1.0
1.2   1.4   1.6  1.8   2.0
  Ratio of amount of combustion air
b.   Pyrolyzing Temperature
     Changes in pyrolyzing temperatures, ignition loss of solid residue and the rate
of decomposition of comsustibles are shown in Fig. 4.8.  The Figures are given for
pyrolysis when the ratio of amount of combustion air was 0.6 and 0.  There is a
tendency that the higher the pyrolyzing temperature, the higher is the decomposi-
tion rate of combustibles and the lower is the ignition loss of solid residue. At the
pyrolyzing  temperature of 900° C, the decomposition of combustibles was almost
completed.  When the ratio of amount of combustion air was 0, the decomposition
rate tended  to drop by about 5%, compared with pyrolysis when  the ratio of amount
of combustion air was 0.6.
     Shown in Fig. 4.9 is the relationship between pyrolyzing temperatures and the
rates of carbon,  hydrogen and  nitrogen remaining in  solid  residue.  When the
pyrolyzing  temperature was over 800°C, most of the ignition loss of solid residue
was carbon. There is  a difference of more than 5% in carbon content in solid residue
between pyrolysis when the ratio of amount of combustion air  was 0 and when the
ratio was 0.6.  There was also a slight difference each in the nitrogen and hydrogen
contents in solid residue according to the differences in the ratio of amount of com-
bustion air at 0 and 0.6.
c.    Feed Loading of Dried Cake
     Experiments were  conducted  on changing feed loading of dried  cake (unit:
kg-DS/m2-hr) with  the pyrolyzing temperature  set at 900° C and the ratio of
                                     175

-------
amount of combustion air at 0.6. Fig. 4.10 shows the changes in the ignition loss of
solid residue and the rate of decomposition of combustibles caused by changes in
feed loading of dried cake.
    With the increase in the feed loading of dried cake, the ignition loss of solid
residue goes up. If the ignition loss of solid residue is to be allowed at  about  10%
when  filling land with solid residue, the adequate feed loading of dried cake is about
25kg-DS/m2-hr.
d.  Detention Time of Dried Cake in Pyrolysis Furnace
    Fig. 4.11 shows  the relationship between the detention time of dried cake in
pyrolysis furnace and both ignition loss of solid residue and the rate of decompose
tion of combustibles. Details are not clear because the data of  experiments  are for
the detention time of  15 min.  and 60  min. only. Estimating from the  Figure,
however, the detention time  of at least 45 minutes seems to be necessary to main-
tain the operating condition of ignition loss of solid residue below 10%.
e.  Recombustion of Exhaust Gas
    Experiments were conducted to grasp the operating conditions of recombus-
tion of exhaust gas from the pyrolysis furnace  in order to burn and decompose
pollutants in the gas  (HCN,  NHs).  As  a result, it became known  that, when  Oz
concentration is over 1%, HCN gas can be decomposed almost completely  at  the
combustion temperature of over 900°C and NH3  gas at over 1,000°C.

             Fig. 4.8 Variation of Both Ignition Loss of Solid Residue
                    and Decomposition Rate to Pyrolyzing Temperature
         100

          90

          80

          70

          60

          50

          40 \-

          30

          20

          10

           0
Decomposition rate of
combustible
Ratio of amount of
combustion air '=. 0.6

                            Ratio of amount of
                            combustion aii = 0
                  Feed loading of dried cake = 10 kg-DS/m2 -hr
  Ignition loss of solid residue
                           Ratio of amount of
                           combustion air = 0
   Ratio of amount of
   combustion air = 0.6
                    600
                                  700           800            900

                                            Pyrolyzing temperature (°C)
                                     176

-------
     Fig. 4.9 Variation of Carbon, Nitrogen and Hydrogen in
             Solid Residue to Pyrolyzing Temperature and
             Ratio of Amount of Combustion Air
    30
u
I
u
n
2
"o
20
    10
                                 Carbon
                                            Ratio of amount of
                                            combustion air % 0
                600        700       800        900

                             Pyrolyzing temperature (°C)
 
-------
 Fig. 4.10 Variation of Both Ignition Loss of Solid Residue
          and Decomposition Rate to Feed Loading of Dried Cake
   100 r

    90

    80
»   70
.2   60
o
p.
o
50
S   40
    30
£?  20
     10
            Decomposition
            rate of combustible
             Ignition loss of
             solid residue
                 10         20         30         40

                        Feed loading of dried cake (kg • DS/m2 • hr)
   Fig. 4.11 Variation of Both Ignition Loss of Solid Residue
            and Decomposition Rate of Combustible to
            Detention Time in Pyrolysis Furnace




i
u
rt
e
.0
Jcomposi
•u
o
WJ
_o
c
.2
'c
bo
100
90
80
70
60


50
40
30


20
10
0
~
__ 	 — 	 	 *
Decomposition rate of combustible
-



-

-


Ignition loss of solid residue
— 	 _ — 1_ 	 i 	 i 	 | 	
15 30 45 60
                                Detention time in pyrolysis furnace (min.)
                          178

-------
4.3.3  PRODUCTS OF DRIED CAKE PYROLYSIS
a.   Remaining Rate of Each Element in Solid Residue
     Table 4.5 shows  the  ratios of various elements remaining in solid residue to
sludge cake.  It also shows three operating conditions of pyrolysis and, for corn-

             Table 4.5 Remaining Rate of Each Component in Solid Residue

Run
No.


1
2
3
4
Pyroly-
zing
Temp.

(°C)
765-
800
80S-
825
880-
910
795-
835
Ratio
Amount
of
Com-
bustion
Air
0
0.67
0.75-
0.77
2.89
Igni-
tion
Loss

(%)
23.6
10.2
2.8
4.8
Gross



(%)
14.4
9.1
0.9
0

C


(%)
30.4
20.3
3.8
4.1

H


(%)
6.6
4.4
3.9
4.0

N


(%)
9.5
3.0
0.5
0

S


(%)
95.5
115.6
86.7
99.6

0


(%)
39.5
25.5
12.1
13.6

Cl


(%)
65.4
67.5
62.2
58.4

Hg


(%)
<1.5
<1.7
<1.5
<1.5

As


(%)
68.5
77.7
68.5
54.2

Cd


(%)
32.9
28.7
27.4
31.7

Pb


(%)
67.7
53.9
27.6
33.3

Zn


(%)
90.8
113.8
95.0
84.3

Cu


(%)
102.4
125.1
93.2
85.4

Ft


(%)
95.4
82.4
96.3
97.5

T-Cr


(%)
100.7
135.2
97.9
90.6
parison, remaining rate of each element in solid residue.
     The higher the pyrolyzing temperature and the ratio of amount of combustion
air, the smaller becomes the ignition loss, thus decreasing the calorific value of solid
residue. In other words, the solid residue becomes closer to that of incineration.
     Analyses of  six elements show that, in  the case of  pyrolysis, the amounts of
carbon, hydrogen, nitrogen and oxygen remaining in solid residue differ, depending
on pyrolyzing temperature and  ratio of amount of combustion air, while the
amounts of sulfer and chloride vary widely.  Concerning chloride, there was a dif-
ference in amount remaining in solid residue between pyrolysis and  incineration.
Pyrolysis tends to vaporize less chloride than incineration.
     Concerning such heavy metals as mercury, cadmium and iron, there is hardly
any difference in  amount remaining in solid residue between pyrolysis  and incinera-
tion.  But pyrolysis can  slightly reduce the vaporization into the air of  arsenic, zinc,
copper and total chromium, compared with incineration.  It was also found that the
amount of lead vaporized into the air differs greatly, depending on operating con-
ditions of pyrolysis.
b.   Concentration and Particle Size Distribution of Dust
     The concentration of dust at the outlet of furnace at the time of pyrolysis was
a range between 0,5 ~ 2.87 g/Nm3, or almost at the same level as the concentration
of dust in incineration.  However, most of the dust  particles generated by pyrolysis
are more than 20/u  in size. A calculation of the efficiency  of dust removal by the
scrubber showed that the dust removal rate was a range between 75 ~ 97%.
c.   Behavior of Nitrogen in Products
     How nitrogen in  sludge changes form at  the outlet of the furnace  as a result of
pyrolysis or incineration is shown in Fig. 4.12(1).
     In the case of incineration, most of  the nitrogen in sludge is estimated to have
changed into nitrogen gas. In the case  of pyrolysis, about 30% of the nitrogen in
sludge exists in the form of ammonia gas, 2 ~ 5%in the form  of hydrogen cyanide gas
and 1 ~ 10%  remains in solid residue, although the amounts differ, depending on
                                     179

-------
operating conditions.  The remainder is estimated to turn into nitrogen gas.  At the
pyrolyzing  temperature of 900° C, the amount of hydrogen cyanide gas generated by
pyrolysis tended to get  larger than at 800° C.  These hydrogen  cyanide gas and
ammonia gas could be decomposed almost completely, when burned in the combus-
tion chamber at the temperature of 1,000°C and at the oxygen concentration  of 1 ~
2% in the chamber.

        Fig.  4.12  Bahaviour of Nitrogen, Sulfur and  Chloride in Products of Pyrolysis
      (1) Behavious of nitrogen in products
100
80
60

40

20

0
-


1
4.8

r35.7

9.5
fS//S

• - I


\\^
5.8

31.5


2
V SS /

^ .




3
1 . O^^2E2
23.9 '•;-
o s| '- -
                                                            HCN gas

                                                            NH3 gas
                                                            Solid residue
      (2) Behaviour of sulfur in products
                      2
  100

   80

   60

§  40
D
a.
   20

    0
       1
95.5
         115.6
                    3.6
                    8.9
                          86.7
99.6
  100

   80

   60

|  40
u
a.
   20

    0
      (3) Behaviour of chloride in products
            1
                      2
      21.5
     1-65.4
                15.0
         67.5
                         33.3
                         62.2
                                  21.6,
                                  58.4
                                                             Condition of experiment
                                                           1. T = 765 - 800°C
                                                             m = 0
                                                           2. T = 805 - 825°C
                                                             m = 0.67
                                                           3. T = 880~ 910°C
                                                             m = 0.75 - 0.77
                                                           4. T = 795 - 835
                                                             m = 2.89
H:Sgas
SOX gas

Solid residue

T:   Pyrolyzing temperature
m:  Ratio of amount of com-
    bustion air
                                                            HC1 gas

                                                            Solid residue
                                       180

-------
d.   Behavior of Sulfer in Products
     How  sulfer in sludge changes form by pyrolysis  or incineration is shown in
Fig. 4.12(2).  With the exception of No.3 as shown by the Figure, the sulfer in
sludge all remained in solid residue.  In the case of incineration (No. 4), too, all the
sulfer in sludge remained in solid residue.
     Of the data  shown in Fig. 4.12(2), No.3  shows an efficient and economical
operating condition for pyrolysis, under which part of the sulfer in sludge turns into
hydrogen sulfide and SOX.  Since hydrogen sulfide turns into SOX when burned in
the combustion chamber at the temperature of about 1,000°C, it is estimated that,
under the operating condition of No. 3, about  12% of the sulfer is considered to
change into SOX.
e.   Behavior of Chloride in Products
     As shown by Fig. 4.12(3), about 60% of chloride in sludge remains  in solid
residue, while part of it is converted into hydrogen chloride.  But it was not detected
in the form of chlorine gas.
     Compared with  pyrolysis, incineration tends to generate a considerably large
amount of hydrogen chloride. In either case,  however, the integrated amount of
chloride does not reach 100% and it is not known whether there was a measurement
error or the remainder exists in the form of another compound.
f.    Offensive Odor Components in Exhaust Gas
     The results of measurement of offensive odor components in dry exhaust gas is
shown in Table 4.6.  The measurement was made only on the experiment condition
No. 3 (at the pyrolyzing temperature of 880 ~ 910°C with the ratio of amount of
combustion air set at 0.75 ~ 0.77).  Gi in the Table shows the sampling point for
gas at the outlet of dryer, 63  at the outlet of pyrolysis furnace  and GA at the outlet
of combustion chamber.  Main offensive odor components at Gi are acetaldehyde
and ammonia, and a little amounts of methyl mercaptan,  dimethyl disulfide,  tri-
methylamine and carbon disulfide were also detected.
     The main offensive  odor components at Gs are  hydrogen sulfide, ammonia and
formaldehyde. A little amounts of carbon disulfide, trimethylamine and acetalde-
hyde were also detected.
     Exhaust gas sampled at G4 after gas at Gi  and Gs  are burned and decomposed
in the combustion chamber does not contain major offensive odor components at
all.  Only very small amounts  of methyl sulfide, ammonia, acetaldehyde and carbon
disulfide are contained in the exhaust gas.

        Table 4.6  Analytical Results of Offensive Odor Component in Exhaust Gas
Run
No.
3
Pyroly-
zing
Temp.
(°C)
880-
910
Ratio of
Amount
ofCom-
bustion
Air
0.75-
0.77
Portion
of
Sam-
pling
GI
G3
G4
H,S
(ppm)
0.02
11
<0.02
Methyl
Mercap-
tan
(ppm)
0.006
<0.006
•C0.006
Methyl
Sulfide
(ppm)
<0.005
<0.002
0.002
Tri-
Methyl-
amine
(ppm)
0.003
0.003
0.001
NHj
(ppm)
0.09
980
0.74
Di-
methyl
Disul-
fide
(ppm)
0.04
<0.001
<0.001
Ster-
ane
(ppm)
<0.02
<0.002
<0.002
Acetal-
dehyde
(ppm)
1.8
0.002
0.007
Form-
alde-
hyde
(ppm)
<0.05
1.1
<0.04
Acetic
Acid
(ppm)
<2
<3
<3
Carbon
Bisul-
fide
(ppm)
0.09
0.15
0.0005
Degree
of
Odor
(Times)
100
25
1
                                    181

-------
g
    Washed Waste Quality of Exhaust Gas and Their Countermeasure
    The results  of  analysis  of  washed waste of dried exhaust gas are shown in
Table 4.7. As shown in  the Table, the washed waste contains a little amounts of
zinc, copper and  iron in addition to 0.002 ~ 0.006 mg/£ of mercury. The problem
involved in washed waste quality is that of pH. However, it became clear as a result
of experiments for practical study.

             Table 4.7 Washed Wastewater Quality Results of Exhaust Gas


Run
No.

1
2
3
4

Pyroly-
zing
Temp.
<°C)
1,050-
1,090
990-
1,050
1,020-
1090
1,060-
1,100
Com-
bustion
Cham-
ber
0,/CO
(Vol %)
1.4/0
1.3/0
1.3-
2.0/0
1.8/0



pH

4.3
4.7
7.1
3.5


BOD

(mg/S)
2
2
2
2


SS

(mg/S)
30
16
17
9


CN-

(mg/C)
<0.01
<0.01
<0.01
0.03

Phenol
Com-
pound
(mg/S)
0.01
0.02
<0.03
<0.03


Hg

(mg/S)
0.004
0.006
0.005
0.002


As

(mg/E)
<0.01
<0.01
<0.01
<0.01


Cd

(mg/f>)
<0.01
<0.01
0.01
<0.01


Pb

(mg/S)
<0.05
0.09
0.05
<0.05


Zn

(mg/S)
0.22
0.19
0.26
0.14


Cu

(mg/S)
0.02
0.02
0.01
0.01


Fe

(mg/S)
7.6
3.2
3.9
3.7


T-Cr

(mg/S)
<0.01
<0.01
<0.01
<0.01


Cr+6

(mg/S)
<0.01
<0.01
<0.01
<0.01
4.4   PRACTICAL STUDY ON DRYING-PYROLYSIS PROCESS
    Experiment  for practical  study were conducted on the basis of the results of
the basic study mentioned in Section 4.3 by using the pilot plant shown in Fig. 4.2.
In the experiments, an indirect steam dryer and a pyrolysis furnace were operated
continuously, and the results of the experiments were compiled. The  series of ex-
periments were conducted by changing pyrolyzing temperature and feed loading of
dewatered cake.  The results  of the experiments are  shown  in Table  4.8.  Run
No. 801  ~ 808 in the Table mean a series of continuous experiments on drying-
pyrolysis process, and Run No. 809 was an experiment to feed into the pyrolysis
furnace  dried cakes stocked in  the dry cake feeder.  Analysis of products was done
only on  Run No.  803 and No. 804.
4.4.1   EXPERIMENTS ON DRYING  FOR DEWATERED CAKE USING  BY
       INDIRECT STEAM DRYER
    The indirect steam drying of dewatered cakes was carried out more efficiently
than in basic study.  Its Overall Heat Transfer Coefficient (U) was 140  ~ 170 Kcal/
m2-hr-°C, which  means a  sharp rise in efficiency compared with 70  ~ 110 Kcal/
m2 'hr'°C in the basic study.
    The paddle type dryer used in the experiments for practical study was a four-
shaft dryer whose mixing frequency is higher than the two-shaft paddle  type dryer
used in  the basic  study. It is  presumed that, for this reason,  the heat transfer ef-
ficiency was raised.
4.4.2   EXPERIMENTS ON PYROLYSIS
a.  Pyrolyzing Temperature
    Fig. 4.13 shows the variations in the ignition loss of solid residue  and in the
decomposition rate of  combustibles, when pyrolyzing temperature was changed
between  700 and 900°C.  In the experiments, feed loading of dewatered cake was
                                   182

-------
   Table 4.8 Operating Results of Drying — Pyrolysis Process at the Practical Study
Operating
Condition
Samples of
Dewatered
Cake




Indirect
Steam
Dryer





Combustion
Chamber


Exhaust
Gas
Boiler

•Jo.1 Scrub-
bei and De-
humidifier
•Jo.2 Scrub-
ber and De-
humidifier







Pyrolysis
Furnace










Heat
Souice
Chamber


Quality
of Solid
Residue




' — - — — 	 	 Run No,
Items " 	 _____
Moisture Contents of Cake (96)
Gross Calorific Value (Kcal/kg-DS)
Ignition Loss of Cake
Pressure of Steam Used (kg/cm3 -G)
Temperature of Steam Used (°C)
Feed Rate of Dewatered Cake (kg/hr.)
Moisture Contents of Dried Cake (%)
Amount of Dried Cake Discharge (kg/hr.)
Amount of Vaporized Water (kg-H,O/hr.)
Amount of Condensed Water (kg/hr.)
Shaft and Screw Side (kg/hr.)
Jacket Side (kg/hr.)
Amount of Heat Transfer (Input] (Kcal/hr.)
Overall Heat Transfer Coef. (Kcal/m1 -hr-°C)
Temperature of Combustion Chamber (°C)
Fuel Consumption (B/hr.)
CO/0,
Outlet Temp, of Exhaust Gas Boiler (°C)
Pressure of Boiler (kg/cm] -G)
Amount of Steam Generated (kg/hr.)
Amount of Steam Discharged (kg/hr.)
Flow-rate of Scrubbing Water (ms /hr.)
Temperature at Outlet of Scrubber (°C)
Amount of Exhaust Gas (mj /hr )
Row-rate of Scrubbing Water (m1 /hr.)
Temperature at Outlet of Scrubber (°C)
Feed Rate of Dried Cake (kg/hr.)
Moisture Contents of Dried Cake (%)
Feed Loading of Dried Cake (kg-DS/mJ -hr.)
Amount of Combustion Air SupplytNm1/^.)
Distribution Rate, 1:2:3:4
Ratio of Amount of Combustion Air
Amount of Propane Gas Consumed
Temperature 1st Hearth
2nd Hearth
3rd Hearth
4th Hearth
Detention Time of Dried Cake (mm.)
Static Pressure (mmAq)
o .1 . r- CO H Vol (%)
Outlet Gas <-"£.. Vol.(*>
C,H,,C,H,, Vol. (%)
O3 Vol. (%)
Calorific Value (Kcal/Nm'l
Circulating Gas Temperature (°)
Flow Rate of Circulating Gas (mj /hr.)
Amount of Fuel Consumed (2/hr.)
Amount of Air Supplied (Nm'/hr.)
Temperature in Heat Source Chamber (°C)
Amount of Solid Residue (Drykg/hr.)
Ignition Loss (%)
Decomposition Rate of Combustible (%)
Solved Concentration of Cr+6 (mg/1)
Cr+6 Contents (mg/kg)
(1/rir.)

mp"0" (1/ton-Cake)
801

75.8
2900
59.5
1.6-2.6
128-139
154.1
34.9
57.3
96.8
135
82
53
67,635
176.2
1100-1170
10.3
0/0.4-1.5
204-210
3.6-4.1
204.3
0
3.6-3.9
24-30
35-120
0.8
24-27
57.3
34.9
23.0
83
0:39:44:0
0.77
0.3
465-575
695-720
775-810
705-785
60
+3-+20
0.57.0.12.
0.04
ND.ND,
0.31
24.8
202-210
40
3.5
44
760-890
18.9
20.0
83.0
ND
3.5
14.5

94.2
802

75.8
2900
59.5
2.7-3.8
139-150
203.2
36.3
77.2
126
158
98
60
78,327
168.6
1030-1120
8.6
0/0.9-3.0
208-226
4.3-5.3
2 if. 2
0
2.0-2.1
28-30
50-75
0.8
45-48
77.2
36.3
30.4
80
0:36:44:0
0.56
0.5
770-795
775-840
815-830
790-830
60
+0-+1.2
1 72 0.99
0.42
0.19, ND.
0.27
181.2
208-226
72.4
6.6
75.2
860-940
23.5
152
87.8
ND
4.8
16.5

81.2
803

75.8
2900
59.5
4.5-5.2
155-159
200.1
35.1
74.6
125.5
174
105
69
85,532
142.8
1000-1090
4.8
0/1.2
230-240
6.0-6.5
212.7
0
3.8-3.9
28-32

0.8
42-50
74.6
35.1
29.9
86
0:42:44:0
0.61
0.7
810-885
890-920
910-935
880-920
60
*7~H5
1 34, 1.64,
0.34
0.11, ND,
0.17
139.6
230-240
41.2
8.1
73.5
1030-1100
21.3
8.1
94.0
ND
5.8
14.7

73.7
804

75.8
2900
59.5
3.6-4.5
148-155
182.5
37.1
71.1
113.7
170
103
67
83,881
156.7
1035-1130
5.9
0/1.3
219-235
5.4-6.0
212.8
0
2.8-3.2
27-30

0.8
46-52
71.1
37.1
27.6
86
0:42:44-0
0.66
0.7
870-905
875-920
880-905
890-920
60
-H5-+25
0.95 1.35,
0.24
0.12, ND.
0.26
110.7
219-235
42.2
7.3
65.8
1050-1130
198
8.5
93.7
ND
6.0
14.8

81 3
805

77.5
3140
61.4
1.6-3.4
130-145
101.4
24.7
30.3
71.1
126
75
51
63,000
155.9
960-1055
5.2
0/1.2
190-198
3.2-4.5
210.8
0-20
0.9-2.3
21-31
50-113
0.8
32-55
30.3
24.7
14.1
48.5
0:20:28.5:0
0.68
1.4
890-930
900-930
875-930
860-900
60
+7~t20
1.40, 1.62,
0.34
ND.ND,
0.13
1243
190-198
50
7.3
62.0
1025-1075
8.9
0.9
99.4
ND
3.6
16.1

1594
806

77.5
3140
61.4
4.3-5.2
157
176.1
37.1
63.0
113.1
185.1
1139
72.2
90,884
151.2
1070-1130
8.3
0.1/0.8-1.3
215-225
5.8-6.8
212.5
0
1.2
20-30

0.8
42-52
63.0
37.1
24.4
92
0:46:46:0
0.74
1.0
870-920
885-930
880-920
900-930
60
+2-HO
0.15. 0.37,
ND
ND.ND,
0.53
21.9
215-226
45.1
6.5
58.1
920-990
15.8
3.3
979
ND
2.4
17.4

78.7
807

76.5
3090
59.6
5.1-5.2
150-160
239.0
43.6
99.6
139.4
183
117
66
89,712
146.6
1080-1150
10.2
0/1.2
216-245
5.2-7.0
213.4
0
3.6-3.9
32-35
65-95
0.8
41-59
99.6
436
34.7
108
0:54:54.0
0.62
0.9
795-825
880-915
920-940
870-890
60
-HO-+20
1.72. 1.90,
0.16
1.04, ND.
020
131 4
216-245
323
7.7
54.3
1000-1100
24 7
7.9
94.2
ND
0.9
20.3

84.9
808

76.5
2960
59.5
5.0-5.3
160
256.0
40.4
101.0
155.2
192
119
73
93,982
150.1
1090-1160
9.9
0/0.5-1.2
238-245
7.2-7.6
216.7
0
3.4-3.5
33-36
40-70
0.8
33-36
101.0
404
37.2
128
0:64:64-0
0.72
0.5
805-895
890-920
910-955
880-920
60
•HO-+20
0.57.0.21.
ND
ND, ND.
0.2
23.7
238-245
26.8
7.0
55.0
1085-1190
26 8
9.3
93.0
ND
09
18 2

71.2
809

(77.5)
(3140)
(61.4)
-









-
960-1000
*0
0/2 1
_


-
-


0.8
47-52
103.9
28.8
438
148
0:74:74:0
0.66
0.3
885-920
890-930
880-905
810-925
60
»3~+20
1.11, 1 73,
0.24
ND.ND.
O.I
97.1
186-204
53.6
6.7
59.2
940-1040
31 2
123
91.2
ND
1.7
-

-
      Remark: Run No. 809 is Experiment of Pyrolysis Process by Dried Cake Feed.
set  at about  30 kg-DS/m2 -hr and the ratio of amount of combustion air at about
0.6. As shown by the Figure, it was found that, if pyrolysis is done at temperatures
of 900°C or more, the ignition loss of solid residue is below 10%.
     And  Fig. 4.14 shows the relationship between pyrolyzing temperatures and
fuel consumption.  Given in the Figure are the  fuel consumption in the pyrolysis
furnace alone and the total fuel consumption  in the pyrolysis furnace and the
combustion chamber.  The amount of fuel consumed in the pyrolysis furnace can be
divided into  fuel consumed in the heat source chamber and fuel directly supplied
in the  pyrolysis furnace.  Propane gas  burners were used  for direct heating of the
pyrolysis furnace.  Listed  in the Figure is the amount  of fuel  which was converted,
on the basis of calorific value, from the amount of propane gas used in the pyrolysis
furnace for direct heating.
                                      183

-------
o
ex
o
o
•8
s
100

 90

 80

 70

 60

 50

 40

 30 -

 20

 10
          Fig. 4:13 Variation of Both Ignition Loss of Solid Residue and
                   Decomposition Rate in Combustible to Pyrolyzing
                   Temperature

                                        803

                801   ^ — —-*""
                   •—         Decomposition rate
                              in combustible
                                        Numerals show run number of
                                        each experiment in figure
Ratio of amount of combustion air = 0.6
Feed loading of dried cake = 10 kg • DS/m2 • hr
                             Ignition loss of
                             solid residue
                           802
                                     803,804
                 700        800       900
                             Pyrolyzing temperature (°C)
            Fig. 4.14  Relationship between Pyrolyzing Temperature
                     and Fuel Consumption

                             Ratio of amount of combustion air =. 0.6
                             Feed loading of dried cake = 10 kg • DS/m2 • hr




^
o
i
ed
o
0>
Ctt
C
o
'p!
D.
E
crt
C
o
o
3
b.


180
160

140

120


100


-

Total fuel consumption



s' | Heat source chamber and propane "1
/ for pyrolysis furnace and combustion |
/ 1^ chamber
/

/ Numeral
801 / number
°X. * experim
^^
\. 802 803
80 f- -c 	 „


60
40

20
0
— ^"»»
0
1
/

s show run
of each
ent in figure





80^ ^_ Fuel consumption for pyrolysis
^r-^. . f Heat source chamber and |
-^-*'^***803 1 propane for pyrolysis furnace J
.— - " 802
801
	 . — i 	 i
700 800 900




                               Pyrolyzing temperature (°C)
                                     184

-------
    Fig. 4.14 shows that, if operation of pyrolysis is carried out at low tempera-
tures,  the amount of fuel supplied to the pyrolysis furnace is reduced, but the total
amount  of fuel used in the furnace and the combustion chamber tends to increase.
    Considering from  these results  of experiments, it might be said that effective
temperature of the dried cake pyrolysis is at about 900° C.
b.   Feed Loading of Dewatered Cake.
    In the experiments for practical study, the feed loading of dewatered cake was
changed in the range of 14 ~ 44 kg-DS/m2-hr, while the pyrolyzing temperature
was kept at about 900°C and  the ratio of amount of combustion air at about 0.6.
Fig. 4.15 shows the relationship between  feed loading of dewatered cake, ignition
loss of solid residue and the decomposition rate of combustibles.   When the feed
loading of dewatered cake was below 25 kg/m2 -hr, as shown in the Figure, the igni-
tion loss of solid residue could be decreased almost to the same extent as in the case
of incineration.  If the  ignition loss is allowed to be 10^ the maximum feed loading
of dewatered cake, in case the water content of the cake is around 30% at the inlet
of the pyrolysis furnace, can be increased to 40 kg-DS/m2 -hr. It me'ans an increase
of 60%over the 25 kg-DS/m2 -hr, the feed loading of dewatered cake obtained in the
basic study.

              Fig. 4.15 Variation of Both Ignition Loss of Solid Residue
                       and Decomposition Rate in Combustible to Feed
                       Loading of Dried Cake

                                  Ratio of amount of combustion air =5 96
                                  Pyrolyzing temp. = 900°C
      o
      ex
      I
      
      •o
      IM
      O
100

 90

 80

 70

 60

 50

 40

 30

 20

 10
                        805
                         »— .
  806
•~,  804   807  g
   ^--. --- *..?j
       803

 Decomposition rate in
 combustible
                                                    809
                                           Numerals show run
                                           number of each
                                           experiment in figure
                              Ignition loss of solid residue
                                                    809
                                     804   807
                        805
                     10       20       30        40        50

                                      Feed loading of dried cake (kg • DS/mJ • hr)
                                     185

-------
     Fig. 4.16 shows the relationship between feed loading of dewatered cake and
fuel  consumption. The classification of the fuel consumed was made in the same
method as in the foregoing Fig. 4.14.  It is learned that fuel consumption is greatly
influenced by feed loading of dewatered cake into the pyrolysis furnace. When feed
loading of dewatered cake is small, fuel consumption increases.  In case the feed
loading of dewatered cake is larger than 25 kg-DS/m2 -hr, fuel consumption is 80 ~
90 litre per ton-wet cake.
     In case  the allowable ignition loss of solid residue is set at 10%, as mentioned
earlier,  and   when the  feed  loading of dewatered  cake is 40 kg-DS/m2-hr, the
amount of fuel used for pyrolysis is about 30 litre per ton-wet cake and the total
fuel consumption is about  80 litre per ton-wet cake.

               Fig. 4.16  Variation of Fuel Consumption to Feed Loading
                       of Dried Cake
                                 Ratio of amount of combustion air % 0.6.
                                 Pyrolyzing temp. = 900°C
         160 -
805
 o
     I
     o.
     6
     I
     o
      3
      tL,
140 - \*'V'
- Total fuel consumption

\ ( Heat source chamber and propane for ^
120 - \
805 \
100 - *\
80 - Fuel consumptions.
for pyrolysis \
60-1 Heat source chamber T
and propane for pyrolysis
(^ furnace J
40 -

20 -
i i
10 20
l^ pyrolysis furnace and combustion chamber J
w
\ 806
o
\ 804 807
\o 	 °_
803 808
\806 8Q4
*~— .^807
803 ^. 80g

•^^,^809
*
i i
30 40



Numerals show
run number of
each experiment
in figure




1
50
                               Feed loading of dried cake (kg • DS/m2 • hr)


4.4.3  PRODUCTS OF DRIED  CAKE PYROLYSIS
a.    Remaining Rate of Each Element in Solid Residue
     The results of analyses  of  dewatered cake and solid residue are  shown in
Table 4.9.  Table 4.10 shows the remaining rate of each element  in solid residue
calculated on the basis of Table 4.9.  From  Table 4.9 and Table 4.10, the elements
other than those remaining in solid residue show the amount or rate of elements
which are estimated to have gone out of the pyrolysis furnace. (Since exhaust gas is
treated in the scrubber and combustion chamber, the amount of elements actually
emitted into the air is decreased sharply.)
     In the measurement of the amount remaining in solid residue or the remaining
                                     186

-------
rate, results  different  from those in the basic study were obtained regarding some
elements.  The elements found to have a high remaining rate in the experiments for
practical study was chloride, whose remaining rate was about 20%higher than in the
basic study.  In contrast, the remaining rate of sulfer was about 30%lower than in
the basic study.  In other words, most of the sulfer remained in solid residue in the
basic study,  while the remaining rate of sulfer was below 60%in the experiments for
practical study.  With regard  to heavy metals, the  amounts of cadmium  and lead
remaining  in solid residue decreased. It is considered that these changes are related
to pyrolyzing temperature.
    The  remaining rate of each  element in solid residue changes according  to
pyrolyzing temperature and it does not follow that pyrolysis is particularly superior
to incineration.
    However, shown  in Table 4.9  is an example denoting the superiority of pyroly-
sis over incineration.  It concerns  the fact that part of the hexavalent chromium
compounds in  sludge is reduced by pyrolysis.  This means that, unlike incineration,
pyrolysis does  not form any new hexavalent chromium compounds but can reduce
even part  of the compounds contained in sludge.  This is a point where pyrolysis is
extremely  superior to incineration.
         Table 4.9 Analytical Results of Both Dewatered Cake and Solid Residue
Items
Dewatered
Cake
Solid
Residue
Items
Dewatered
Cake
Solid
Residue
Run
No.
803
804
803
804
Run
No.
803
804
803
804
Ignition
Loss
(%)
59.5
59.5
8.1
8.5
Hg
(ppm)
0.56
0.54
<0.05
<0.05
Gross
Calorific
Value
(Real/
kg-DS)
2,960
2,860
320
340
As
(ppm)
'5.4
5.0
6.9
8.1
C
(%)
28.4
28.3
3.0
3.9
Cd
(ppm)
11
10
3.4
3.6
H
(%)
4.1
4.2
0.18
0.18
Pb
(ppm)
270
240
98
100
N
(%)
3.1
3.1
<0.5
<0.5
Zn
(ppm)
1,200
1,300
2,500
2,900
S
(%)
1.1
1.0
1.5
1.3
Cu
(ppm)
640
610
1,500
1,500
O
(%)
27.0
27.0
13.0
13.0
Fe
(Ppm)
32,600
31,500
75,200
75,800
Cl
<%)
0.65
0.63
1.26
1.26
T-Cr
(ppm)
330
290
590
730
CN
(ppm)
6.9
3.5
0.23
0.20
Cr*6
(ppm)
8.6
7.8
5.9
6.0
NH3
(ppm)
2,900
1,400
910
170
Cr^-
-^f-Cr
(%)
2.6
2.6
1.0
0.8
    Table 4.10  Remaining Rate of Each Element at the Cake of Drying - Pyrolysis Process

No

803
804
Gross
Calorific
Value
4.8
5.3

C
(%)
4.6
6.2

H
(%)
1.9
1.9

N
(%)
<7.1
<7.2

S
(%)
59.9
57.5

0
<%)
4.8
5.3

CL
<*)
85.4
88.5

CN
(%)
1.5
2.5

NH,
(%)
13.8
5.4

Hg

<1.5
<1.5

As
(%)
56.3
71.7

Cd
(%)
13.6
15.9

Pb
(%)
16.0
18.4

Zn
(%)
91.8
98.7

Cu
(%)
103.3
108.8

Fe
(%)
101.7
106.5

T-Cr
(%)
78.8
111.4
                                     187

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b.   Concentration and Particle Size Distribution of Dust
     As shown by Table 4.11,  the concentration of dust from the pyrolysis furnace
is considerably high.  The concentration of dust is lowered sharply after dust is sent
through  the  scrubber, but it is necessary to install an electric precipitator or other
equipment in order to hold down the dust concentration rate below 0.34 g/Nm3.
     Much of the dust from  the pyrolysis furnace has a relatively large particle size
as shown in  Table  4.12.  Accordingly, it is considered  to be  comparatively easy to
separate  dust by an electric precipitator or other equipment.

                 Table 4.11 Characteristics  of Exhaust Gas (Run No.803)
Sam-
pling
Site
G,
G,
G4
G,
Temp.
of
Gas
<°C)
-
760
215
49
Velocity
of
Gas
(m/sec.)
-
13.8
16.1
1.4
Moisture
Contents
(Vol. %)
Actual

24.6
20.8
10.3
Calcu-
lation
14.5
24.7
21.8
10.4
Volume of
Dry Gas
(Nm3/hr.)
Actual

200
330
280
Calcu-
lation
103
213
308
275
Dust
(g/Nm3)
-
8.4
3.1
0.34
HCN
(ppm)
-
240
<0.1
<0.1
NH3
(ppm)
-
2.080
1.0
0.5
NOx
(ppm)
170
54
210
190
SOx
(ppm)
130
130
230
130
HC1
(ppm)
-
6.0
15.0
1.4
CI,
(ppm)
<0.2
<0.2
<0.2
<0.2
Degree
of
Odor
(Times)
-
400
2
2
 Remark:  G2. Exhaust Gas Samples from Heat Source Chamber
        G3: Exhaust Gas Samples from Pyrolysis Furnace
        G4. Exhaust Gas Samples from Exhaust Gas Boiler
        G5: Exhaust Gas Samples from Gas Scrubber
          Table 4.12  Dust Size Distribution in Exhaust Gas from Pyrolysis Furnace
                    (Run No.804)
Size (M)

Samples
1
2

>6.5

73.8
70.2

4.3-6.5

12.1
12.9

2.8-4.3

6.1
5.8

1.9-2.8

3.2
3.6

1.2-1.9

1.5
2.1

0.6-1.2

0.6
0.9

0.4-1.6

0.9
1.0

0.2-0.4

1.2
1.3

<0.2

0.6
2.2
c.   Components of Exhaust Gas
     Table 4.11  shows the results of analyses  of such exhaust gas components as
hydrogen cyanide, ammonia,  NOX  and SOX.  The amounts of various exhaust gas
components generated in the pyrolysis furnace diminish sharply in the process of
decomposition in the combustion chamber and cleaning by  the scrubber.  For this
reason,  hydrogen  cyanide, ammonia  and  hydrogen  chloride will  do no harm.
However, the amounts of NOX and  SOX do not decrease.  Especially, the concent-
ration of NOX is much higher in exhaust gas  than at the outlet  of the pyrolysis
furnace,  since it is treated in the combustion chamber at temperatures over 1,000°C.
Thus it may become necessary to take steps to remove SOX and NOX, as in the case
of incineration, where the  environmental quality standard on air pollution is being
enforced strictly.
d.   Behavior of Nitrogen, Sulfer and Chloride in Sludge
     The forms of nitrogen, sulfer and chloride  at the outlet of the pyrolysis furnace
                                     188

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is shown in Fig. 4.17. There is hardly any difference in the results of analysis of
nitrogen between  the experiments for practical study and the  basic  study (See
Fig. 4.12).  In the case of sulfer, the results of analysis differed from those in the
basic  study, with the whereabout of about 27% of the substance unknown. As a
result of measurement, it was found that  the amount of sulfer remaining in solid
residue decreased, while an increased amount of SOX was generated.
     The amount of  chloride remaining in solid residue tended to go up by about
20% from the level recorded in the basic study.

                    Fig. 4.17  Forms of Each Element in Product of
                            Pyrolysis
            100

             90

             80

             70

             60

             50

             40

             30

             20

             10

              0
                  13.3
         0.29

         12.4
         60.3
 2.1

19.8
                  85.6
                                  Remark
N
                                C2
} HCN gas
} NH3 gas
I Solid residue
       H2Sgas

      } SOX gas

       Solid residue


      } HC8 gas

      } Solid residue
                     N
e.    Offensive Odor Components in Exhaust Gas
     Table 4.13  shows the results of analyses of offensive odor components in
exhaust gas.  Obtained from the analyses were numerical values  almost similar to
those in the  basic study.  The  main offensive odor components  generated in the
indirect steam  dryer  are  ammonia and acetaldehyde, and those generated in the
pyrolysis furnace are high concentrations of ammonia, hydrogen sulfide and form-
aldehyde.
     Although most of the components  are decreased in amount through the de-
composition in the combustion chamber, the amounts of ammonia, acetaldehyde
and formaldehyde remaining in exhaust  gas were found  to be considerably higher
than those recorded in the basic study.
                                     189

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        Table 4.13 Analytical Results of Offensive Odor Component in Exhaust Gas
Sampling
Site
G
G3
G4 1
H2S
(ppm)
0.07
5.0
<0 008
Methyl
Mercaptan
(ppm)
<0.005
<0.005
<0.005
Methyl
Sulfide
(ppm)
0.08
<0.003
<0.003
Tri-methyl
Amine
(ppm)
0.005
0.002
0.002
Ammonia
(ppm)
8.7
2.080
1.0
Dimethyl
Disulfide
(ppm)
0.5
0.03
<0.002
Sterane
(ppm)
<0.3
<3
<0.02
Acetalde-
hyde
(ppm)
1.0
0.1
0.07
Formal-
dehyde
(ppm)
<0.15
3.9
0.44
Acetic
Acid
(ppm)
<3.0
<3.0
<3.0
Carbon
Disulfide
(Ppm)
0.07
0.6
0.006
Remark:  G, . Exhaust Gas Sample from Indirect Steam Dryer
       G3. Exhaust Gas Sample from Pyrolysis Furnace
       G,: Exhaust Gas Sample from Exhaust Gas Boiler

4.4.4  COMPARISON OF  DRYING-PYROLYSIS  PROCESS, DIRECT
       PYROLYSIS  PROCESS AND  INCINERATION PROCESS
     Experiments were conducted on  the direct pyrolysis process and incineration
process of  dewatered cakes to find out the merits and demerits of the drying-
pyrolysis process. The results of the experiments are shown in Table 4.14. It shows
the results of the Run No. 808 as an example of the drying-pyrolysis  process. The
properties of the dewatered cake  used in Run No. 808 in Table 4.14  is a little dif-
ferent from the dewatered cakes used in Run No. 903 and No. 904. The cake used
in Run No. 808 has  less combustibles than  dewatered cakes used in  Run No. 903
and No. 904 and, therefore, its calorific value is small.  It was difficult to compare
the three processes exactly, but it was  concluded that a tentative comparison would
be possible.
     In Table 4.14, Column I shows  empirical values  and Column  II the values
revised for practical reasons. The revision was made in the following manners.
i)    In the drying-pyrolysis process, it was assumed that the temperature of return-
ing water from  the drain was 80° C and that  measures were  taken to prevent  white
smokes of exhaust gas from gonig out of the chimney.
ii)   In the direct pyrolysis process and incineration process of  dewatered cakes,
it  was  assumed that  heat exchange  was  done by a  heat exchanger, in addition to
the revision made in above Article i).
     Under these  revisions, fuel consumption for the  drying-pyrolysis  process
rises higher than the empirical value  and fuel consumption for direct pyrolysis
process and incineration process goes down from the empirical values.  Nevertheless,
fuel  consumption for the drying-pyrolysis process is about  1/2 of that needed for
direct pyrolysis  process and about  1/3 of that  for incineration process.
     The amount of  exhaust gas generated  by drying-pyrolysis process becomes
considerably smaller  than  that generated by direct pyrolysis process or incinera-
tion process.  This means that the drying-pyrolysis  process could lower the costs
of construction  and  operation  of facilities  to  prevent  air pollution, by  a  larger
margin than direct pyrolysis process and incineration process.
     Comparing direct pyrolysis process with  incineration process, the former is
also considered  to be considerably more  advantageous than the latter economically.
     The experiments were conducted at a pilot  plant, and the  operation of a
practical plant  is expected to produce  results considerably different from  those
obtained in the foregoing  experiments.  For example, in the experiments of Run
                                    190

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          Table 4.14  Comparable Experimental Data of Drying-Pyrolysis
                    Process, Direct Pyrolysis Process and Incineration Process
^ 	 __ Process
^^— — -
Items
• — -^__ "57 r~—- —
--— JlljnNo.
Moisture Contents of Dewatered Cake (%)
Ignition Loss of Cake (%)
Ash Contents of Cake (%)
Gross Calorific Value (Kcal/kg-DS)
Moisture Contents at Inlet of Pyrolysis ,„,,
Furnace (%>
Ratio of Amount of Combustion Air
Exhaust Gas Temperature at Outlet of ,0.-,,
Pyrolysis Furnace *• '
Exhaust Gas Temperature at Outlet of ,0,-,,
Combustion Chamber *• '


Fuel Consumption
(I/ ton -Cake)


Dry Exhaust Gas
(Nm3 /ton-Cake)
Wet Exhaust Gas
(Nm3 /ton -Cake)

I


II

I
II
I
II
Furnace
Combustion Chamber
Total
Furnace
Combustion Chamber
Total
Furnace
Combustion Chamber
Furnace
Combustion Chamber
Furnace
Combustion Chamber
Furnace
Combustion Chamber
Drying-
Pyrolysis
808
16.5
59.5
40.5
2,900
40.4
0.71
850
1,100
33
39
72
33
61
94
858
1,428
858
1,556
1,199
1,651
1,199
1,651
Direct
Pyrolysis
903
77.8
66.0
34
3,300
77.8
0.60
393
800
144
89
233
144
44
188
1,495
2,227
1,495
2,184
2,748
2,381
2,748
2,339
Incinera-
tion
904
77.5
66.0
34
3,300
77.5
2.0
485
800
128
234
362
128
162
290
2,673
4,968
2,673
4,425
3,949
5,350
3,949
4,727
No. 903 and No. 904, the temperatures at the outlet of the furnace were consider-
ably higher than at the outlet of the furnace for practical use.
     For  this  reason,  trial calculations  were made  on  drying-pyrolysis, direct
pyrolysis  and incineration  in  a  practical  use furnace  (Wet Base 50 t/day) by in-
troducing the idea of designing a conventional multi-hearth furnace.  The results of
the calculations are shown in Table 4.15.
     In the  drying-pyrolysis process, as shown in the Table, no fuel is supplied to
the pyrolysis furnace at all since sludge cake is in a dry state. And only a small
amount of  fuel  is  needed  for the  process because exhaust gas generated in the
pyrolysis  furnace is  used as part of the heat source for boiler.  In direct pyrolysis,
fuel consumption for the  pyrolysis furnace  is the largest,  but that for the com-
bustion chamber is  less than  for the drying-pyrolysis process because  no fuel is
needed for  the boiler in the  combustion chamber.  In incineration, less  fuel is
supplied to the furnace than in direct pyrolysis since combustibles are burned in the
furnace, but the amount of fuel used in the combustion  chamber for the combustion
of exhaust gas  is very large.  But  if there is no combustion of exhaust gas, the
amount of fuel for  incineration  is the smallest. In reality, however,  sewage treat-
ment plants in most of the municipalities in Japan are equipped with facilities for
                                      191

-------
            Table 4.15 Comparable Calculation Results of Drying-Pyrolysis
                     Process, Direct Pyrolysis Process and Incineration Process
— 	 _^___^ Process
Items " ~- — ~^____
Moisture Contents of Dewatered Cake (%)
Ignition Loss of Cake (%)
Ash Contents of Cake (%)
Gross Calorific Value (Kcal/kg-DS)
Moisture Contents at Inlet of Pyrolysis I0,\
Furnace {/o)
Ratio of Amount of Combustion Air
Exhaust Gas Temperature at Outlet of fTl
Pyrolysis Furnace ^ '
Exhaust Gas Temperature at Outlet of ,0,-,..
Combustion Chamber l •*
Fuel Consumption
(I/ ton-Cake)
Dry Exhaust Gas
(Mm3 /ton-Cake)
Wet Exhaust Gas
(Nm3 /ton-Cake)
Furnace
Combustion Chamber
Total
Furnace
Combustion Chamber
Furnace
Combustion Chamber
Drying-
Pyrolysis
Process
78
66.0
34
3,300
25
0.60
700
1,100
0
52
52
338
1,302
542
1,408
Direct
Pyrolysis
Process
78
66.0
34
3,300
78
0.60
200
800
44
33
77
879
1,467
1,985
1,636
Incinera-
tion
Process
78
66.0
34
3,300
78
2.0
200
800
27
120
147
2,023
3,302
3,172
3,638
 the  combustion of exhaust gas or for the deodorization by catalyzer in order to
 prevent  the generation of offensive odor and the emission of white smokes from
 chimneys.
     Pyrolysis process can decrease exhaust gas sharply, compared with incineration
 process.   Therefore,  pyrolysis  process  requires less  costs of  construction  and
 operation of such exhaust gas control facilities  as  electric precipitators and alkali
 absorption scrubber.  In this  respect,  pyrolysis process can be  said to have a great
 economic advantage.
 4.5   SUMMARY
     Basic and practical studies were carried out on the drying-pyrolysis process in
 order to  put  to practical use the pyrolysis of sewage sludge by  a multi-hearth
 furnace.  The  sampled sludge for use  in  these studies was dewatered cake of raw
 sludge at the Toba Sewage Treatment  Plant in Kyoto.  The pilot plant for the basic
 study was made up of a two-shaft indirect steam dryer, a single-hearth furnace (with
 a total furnace floor space of 2.1 m2) and its incidental facilities.  The pilot plant
 for the experiments  for  practical  study  consisted  of  a four-shaft  indirect steam
 dryer,  a  four-hearth furnace  (with a total furnace floor space of 1.63 m2) and its
 incidental facilities.
     The results of the studies can be summarized as follows.
(1)  As a result of the experiments for practical study, the Overall Heat Transfer
Coefficient (U) of the indirect steam dryer for sludge cakes drying  could be raised
to 140 ~ 170 Kcal/m2 -hr-°C. It is larger  than the Overall Heat Transfer Coefficient
of 70 ~ 110 Kcal/m2 -hr-°C obtained in the basic study. This is ascribed to the in-
crease in the number of shafts of the indirect steam dryer.
                                      192

-------
(2)  For the drying-pyrolysis process, it is appropriate to set the ratio of amount of
combustion air at 0.5 ~ 0,7 and pyrolyzing  temperature at 900°C in order to keep
the ignition loss  of solid residue below  10%.  According to the experiments  for
practical study, adequate  feed loading of dewatered cake to maintain the same con-
dition is estimated to be 40 kg-DS/m2 -hr.
(3)  Pyrolysis  can completely prevent  the  oxidization  into hexavalent chromium
compounds, of trivalent chromium compounds contained in sludge cakes. And part
of the hexavalent chromium compounds contained in sludge cake are reduced in  the
furnace by reducing gas generated in the pyrolysis furnace.
(4)  At the basic and practical studies, there were found to produce slightly dif-
ferent results with regard  to the remaining rate of each element in solid residue from
pyrolysis.  The difference relates to pyrolyzing temperature.  The remaining rate of
each element in solid residue is related  to temperature, and it does  not follow that
pyrolysis is by  far superior to incineration.
(5)  The amount of  dust  generated  in pyrolysis furnace is considerably large.
Furthermore, many particles are large  in size.  Although most of the dust can be
removed when passed  through  the scrubber, it is also necessary to install an electric
precipitator for maintaining the  concentration of dust  at a very low level  as same
as the case of incineration process.
(6)  Of the exhaust gas  components generated in the pyrolysis furnace, hydrogen
cyanide and  ammonia are  decomposed  in the combustion  chamber.  Hydrogen
chloride can be removed by means of a gas scrubber.  Since SOX and  NOX cannot be
removed, however,  it may  become necessary to  take  measures to deal with  the
problem in areas where  the environmental quality  standard  on  air pollution is
strictly enforced.
(7)  The main offensive  odor components in exhaust gas generated in the indirect
steam dryer are  ammonia and acetaldehyde, and those generated in the pyrolysis
furnace  are much amount of ammonia, hydrogen sulfide and  formaldehyde.  Most
of these components are  diminished through the decomposition in the combustion
chamber, but small amounts of  ammonia,  acetaldehyde and formaldehyde remain
in exhaust gas at the outlet of combustion chamber.
(8)  The drying-pyrolysis process consumes the  least amount of fuel in case there is
combustion of exhaust gas.  But, in case  the  combustion of exhaust gas is not
needed, incineration process consumes the least amount of fuel.
     The drying-pyrolysis process and  direct pyrolysis  process can  reduce the
generation of exhaust  gas to below 1/2  of the amount of exhaust gas generated by
incineration process.  Therefore, pyrolysis process  is  expected  to have  a  great
economic efficiency in case steps are necessary to prevent air pollution and offensive
odor.
                                REFERENCE
(1)   T. Majima et al, Studies on Pyrolysis Process of Sewage Sludge, Proceedings of
the 8th International Conference on  Water Pollution  Research,  Sydney, p. 381
(1976)
                                     193

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                         FIFTH US/JAPAN CONFERENCE
                                    ON
                        SEWAGE TREATMENT TECHNOLOGY
                               PAPER NO, 4
DEVELOPMENT AND EVALUATION OF AUTOMATIC
WATER QUALITY MONITORING EQUIPMENT
            APRIL 26-28, 1977

              TOKYO, JAPAN
         MINISTRY OF CONSTRUCTION

           JAPANESE GOVERNMENT


                   195

-------
DEVELOPMENT AND  EVALUATION  OF AUTOMATIC WATER
QUALITY  MONITORING EQUIPMENT
  K. Murakami, PWRI, Ministry of Construction
                       196

-------
           DEVELOPMENT AND EVALUATION OF AUTOMATIC
              WATER QUALITY MONITORING  EQUIPMENT
1.   Foreward	198
2.   Automatic Measuring Devices to Monitor Quality of Raw Sewage	198
  2.1   Total Cyanide Monitor	198
  2.2   Surface Oil Detector	204
  2.3   Future Development Projects	206
3.   Automatic Water Quality Measurement Devices to Control Waste water
    Treatment Process 	206
  3.1   TOC Analyzer	206
  3.2   Continuous UV Photometer	209
  3.3   Automatic SV and SVI Meter	212
  3.4   Automated Colorimetric Analyzer for Phosphorus	214
  3.5   Other Measuring Instruments	214
    3.5.1  Automatic Cleaning Unit for Dissolved Oxygen Electrode	214
    3.5.2  Ultrasonic Wave Sludge Density Meter	215
    3.5.3  Sludge Level Meter	215
                                  197

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DEVELOPMENT AND EVALUATION  OF AUTOMATIC WATER QUALITY
MONITORING  EQUIPMENT
1.   FOREWORD
     In the field of sewage works, there is a pressing need for the development of
reliable automatic water quality measuring devices for monitoring sewage quality
including industrial wastewater discharged into the public sewage system and for
automatic control of treatment processes.
     The Ministry of Construction gives high priority to the development of measur-
ing devices for detecting toxic substances that may be contained in industrial waste-
water discharged into the public sewage system. The  development of such measur-
ing devices are now being carried out by a contract research with the Association of
Electrical Engineering.
     The Electrical Engineering Association organized a committee composed of
representatives from nine manufacturers and  users for this purpose, and has been
conducting  field tests on the previously developed devices to seek for any possible
technical improvement and developing new instruments with the cooperation of the
manufacturers.
     The development of measuring instruments for automatic control of treatment
processes has also progressed considerably these days.  Although their application
to automatic control is not so popular yet, these instruments are  being installed in
many sewage treatment plants for manual control or monitoring.
     This report summarizes the activities in the field of research and development
of water quality measuring devices in Japan.
2.   AUTOMATIC MEASURING DEVICES TO MONITOR QUALITY OF RAW
     SEWAGE
2.1  TOTAL CYANIDE MONITOR
     On a contract research basis entrusted to the Association of Electrical Engineer-
ing, work has begun to develop a total cyanide monitor from FY 1975.  At that
time, five models of  automatic cyanide  monitors from different manufacturers
were  on the market.  Those units, however, were all  designed for monitoring
cyanides in  industrial wastewater which is usually easy to deal with, and the appli-
cability of these products to sewage was unclear. Therefore, field tests of these units
were conducted at a sewage treatment plant for about three months. It was revealed
that the two models were  completely uncapable of continuous operation and the
other models, although giving comparatively good results, all had defects. Therefore,
efforts were made to develop the  New  Standard Models by improving  previous
models.  Three prototype models were assembled.
     Models I and II are batch-type measuring instruments. Model I incorporats the
method  of removing sulfides  during distillation while  Model II employs the method
                                    198

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of removing sulfides after distillation. Type III, on the other hand, is of a con-
tinuous measuring type.
    All of these prototype models utilize cyanide electrodes as the detector unit.
Models I and II have two kinds of electrodes:  conventional type electrode with an
abrasive unit, and an electrode with the measuring cell itself being a sensing element
as shown in Fig. 1.


                         Fig. 1 New Type Cyanide Electrode
                                                    Reference electrode
                                                       Teflon coated roter
                      Sensing element
     The surface  of the sensing element of the latter type electrode is constantly
cleaned by a rotor.  This electrode, when compared with conventional ones, has a
lower detecting limit giving  a longarithmicly  linear  output down  to 0.01  mg/fi.
     Fig. 2 shows the flow diagram of Model I monitor. After measuring 100 m£ of
sulfuric acid (1+9) and  10 m£ of N/10 potassium permenganate solution is added
to oxidize sulfides and other interferences. Next, before raising the temperature too
high,  10 m£ of N/10 sodium oxalate is added to remove excessive potassium per-
menganate  without  decomposing cyanides.  The  distilled  cyanide  is absorbed in a
0.4%  sodium hydrate  solution and measured by cyanide electrodes.  Measurements
are done at 30  minute intervals.
                                     199

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to
o
o
Sample
                  VMC: Volume Measuring Cup
                  PV:  Pinch Valve
                  SV:  Solenoid Valve
                  P:   Pump
                  NF:  Level Detector
                  FS:  Float Switch
                                                              Fig. 2  MOW Diagram of Total Cyanide Monitor, Model

                                                                                                                 FS,
                                                                                                                                           Tap water
                                                                                   Drain
                                                                         nnrtro"o irv$$oo l
                                                                         O     Heater     O
                                                                                                                                                Drain

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                                                               Fig. 3 Flow Diagram of Total Cyanide Monitor, Model II
INi
o
                    VMC: Volume Measuring Cup
                    PV-  Pinch Valve
                    SV:  Solenoid Valve
                    P    Pump
                    AP.  Air Pump
                                                                                                                               Drain

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                                     Fig. 4  How Diagram of Total Cyanide Monitor, Model III
 P-   Proportioning Pump
 AP-  A,i Pump
 PV   Pinch Valve
 SV:  Solenoid Valve
 SpV- Slop Valve
 NV:  Needle Valve
 MS'  Magnetic Stirrer
Tap water
Standard
solution
  Sample
   Drain

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     Model II is also of a batch type. As shown in the flow diagram in Fig. 3, the
system consists  of distillation under acidic  condition with phosphoric  acid  and
removal of hydrogen sulfide after distillation.
     100 mC of sample water, added with 10 mC of phosphoric acid, is distilled and
distilled cyanide is absorbed in 2% sodium hydroxide solution in the receiving flask.
The  hydrogen sulfide, distilled together with hydrogen cyanide, is removed by the
column either filled with the bismuth treated chilate resin or granular lead peroxide.
The  bismuth treated chilate resin  is a  chilate resin reacted with 0.4 ~ 0.5 mM
bismuth per 1 (one) mC resin. Theoretically it has a  capacity to remove equivalent
hydrogen sulfide.
     The use of such resin prevents the heavy metal for sulfides removal from being
discharged into the effluent.
     Lead peroxide  oxidizes hydrogen sulfide into sulfate ion without producing
any  complex ion of cyanide. The  time  interval of measurements by this model is
one hour.
     Model III  is of a continuous measuring type  as shown in the flow diagram in
Fig. 4.
     200 mfi/hr of sample water is continuously supplied into the distillation  flask
and  distilled  almost instantaneously by  heated  phosphoric acid in the flask.  2%
sodium hydrate solution at a flow rate of 10 m£/hr is added to the distillate, and the
cyanide is measured by  an electrode.   Since non-distillated  substances such as
minerals accumulate in the distillation flask, phosphoric acid is replaced once every
day to wash the flask.
     Sulfides, as is in Model II,  are removed after  distillation by  permeating the
distillate through the desulfurizing column.
     These three type units, completed in December  1976, are currently undergoing
field tests at an actual sewage treatment  plant.  The  influent to the plant is  mainly
composed of metal-finishing wastewater  and contains very small amount of dome-
stic  sewage.  The  water sample presently used for the field test  is the  chemical
clarified effluent from the plant.
     Major troubles found during the field test were:
(a)   Distillation efficiency during night time  deteriorated due to insufficient distil-
lation heater capacity of Models I and II.
(b)   Cyanide recovery rate was inconsistent owing to dew  drops developing in the
tube linking the condenser with the distillate receiver, and
(c)   Some substance in  the tap water which was used for wash water interfered the
measurement.  This substance is considered to be either free chlorine or the sub-
stance which forms a complex cyanide compound.
     Modifications of the instruments were made,  and  field tests are presently con-
ducted of the modified units.
     After completing the test using clarified effluent, field tests will be continued
using raw sewage as the sample.
                                      203

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2.2  SURFACE OIL  DETECTOR
     Contract research  with the Association of Electrical Engineering also covers
evaluation  and development of surface oil detectors. Various types of oil detectors
are already on the market. Two types of surface oil detectors were selected to carry
out field tests for examining their applicability. One model  is based  on the fluore-
scence emitted from oils being irradiated by UV rays. The other model is based on
the difference in reflectivities between oils and water. Both models have essentially
the same structures.  A  pair of turbular floats support a light source and a light
receiver, keeping  a  prefixed distance  between the  detector  unit and the water
surface.
     In former type oil detector, an ultra-violet ray of 253.7 nm  in wave length is
projected and the fluorescence light is detected by a photo multiplier.  It can detect
crude oil, heavy oil and lubricants.  However, it is not good for oils that do not pro-
duce fluorescence, such  as gasoline, kerosene, vegetable oil and animal fat. As far
as the  detectable oils  are concerned, the detector can measure the  oil  film thickness
to a certain degree when the type of the oil is given.  This detector has an automatic
calibration mechanism that  can  correct the effects of the deterioration of light
source and  temperature changes.
     The field  test lasted for  about a month  and  a half without producing any
mechanical  malfunctions thus  satisfactory measurement results were obtained.
Possible  interferences may  be detergent fluorescent and phenol  contained in the
sewage.  However, the baseline drift during the  field  test was extremely small, and
the interferences can be considered negligible.
     The principle  of measurement of the other model  is the  difference in the
reflectivities between  water  and oil.  The water reflectivity is normally 2%, and that
of oil is between 3.5 and 6% depending upon the type of oil. Hence, the existence
of surface  oil can be detected by merely measuring the  reflectivity.  The pulsed
infrared beam is used to minimize the effect of the ambient light.  Dissolved and
suspended elements in the water do not interefere with the measurements.
     During a month and a half long field test, no maintenance was necessary except
when scum covered the whole water surface, and the performance was satisfactory.
     Both oil detectors mentioned above has comparatively large floats and require
a wide space to install.  Therefore, it was planned to develope an oil detector which
needs smaller space.  The new model being developed is also based  on  the difference
in reflectivities between water and oil but uses  a laser as the  light source.  Since the
intensity of laser beam is practically indipendent on the light path, the reflectivity
measurement  is scarcely affected  by  v,;ater level changes,  which  eliminates the
necessity of the floats. The block diagram of the barrack model is shown in Fig. 5.
     The light source is  1 mW He-Ne laser with wave  length of 633 nm.  The light
beam from  the lazer is projected on the  water surface via the mirror through a
transparent  part at the center. A part  of the light reflected on the reverse side of
the mirror  goes into  the  photo cell on the left side as a  reference.  The reflected
light from the water surface  travels to the concave mirror via the central mirror and
gathers at the photo cell for detection.
                                      204

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              Fig. 5 Block Diagram of Surface Oil Detector Using Laser Beam
             Laser
             Mirror
             Photo Cell for Reference
             Concave Mirror
             Photo Cell for Detection
            7"  Amplifiers
             Syncroscope
          9:  Water Surface
     The barrack model employs a synchroscope to read the output from the photo
cells. The intensity of the laser beam is comparatively strong, so that the effect of
the ambient light seems to be small.  But it may be necessary to use a pulsed beam
by means of a chopper to put the model into practical use.
     Further studies are  being done  on the output  system and so on.  Laboratory
and field tests are currently under way.  This model, upon completion for practical
use, will enable measurement even in narrow manholes.
                                      205

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2.3  FUTURE DEVELOPMENT PROJECTS
     The contract research entrusted to the Association of Electrical Engineering
will include studies of (a) developing total-chromium and copper monitors based on
automated colorimetric analysis, (b) developing a cadmium monitor based on ion
selective electrode method and (c) conducting  field test to examine the feasibilities
of these devices for future practical use.
     With regards to total chromium and copper monitors, automated colorimetric
analysis would be a practical method since regents appropriate for automation are
available.  Products based on this method are already on the market.  Presently,
researches are  conducted  on the pretreatment methods to maximize the dissolved
fractions of chromium and copper in sewage.
     Automated  colorimetric analysis of cadmium does not seem to be practicable,
as suitable  reagents are not available  yet.  Ion selective electrode  for cadmium,
although promissing,  is  interfered  greately  by  organic substances.  Therefore,
methods to effectively remove organic interferences are now being studied.
     Furthermore,  basic studies will be initiated to apply flameless atomic absorp-
tion spectometry and anode stripping voltimetry methods to water quality monitors.
3.   AUTOMATIC WATER QUALITY MEASUREMENT DEVICES TO
     CONTROL  WASTEWATER TREATMENT PROCESS
3.1  TOC  ANALYZER
     Nishiyama Sewage Treatment Plant  is utilized as  a demonstration plant to
evaleate the effect of chemical coagulat addition to the aeration tank.  A continuous
TOC analyzer was installed  at  the  plant on March 1976 and has been operated
successfully. This TOC analyzer is an improved version based on the experimences
at the Morigasaki Sewage Treatment Plant and the Arakawa River Left Bank Sewage
Treatment Plant, as presented at the 4th Conference.
     The major purpose of this TOC analyzer installation is to study the conversion
of dissolved organics into  activated sludge in  the  biological treatment process.
Hovvever, die sampling system is designed to feed the analyzer the following four
kinds of samples at 90 min. intervals in turns by an automatic sample exchanger:
primary effluent, secondary  effluents  from both control and chemical addition
systems, and filtered secondary effluent.
     Suspended solids in  primary effluent is  removed  by  a compact continuous
centrifuge having a bowl capacity of 3  liters. This centrifuge requires manual Inter-
mittent operation to discharge centrifuged solids every two weeks. By conducting
centrifugal operation under the feed rate of 2.5 £/min. at 4,000 rpm, 30 ~ 80 mg/2
suspended solids in the primary effluent can be lowered to 5 ~ 10  mg/£.
                                    206

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    Several minor troubles developed since commencing continuous operation of
the analyzer.  But none was  so serious  to stop the measurement, and data were
obtained almost 100% of the period.
    Troubles experienced so far are as follows:
(1) The tubing at the inlet  and outlet of the infrared analyzer deteriorated in
quality faster than expected.  The replacement of the tubing can be done only by
the manufacturer.
(2) The cleaning of the scrubber for 1C removal is extremely difficult because of its
ill-designed setup.
(3) The sample feed pump clogged often.
(4) The pipe at  the outlet of the furnace corroded considerably, and should be
replaced within one year.
(5) The corrosion of the inside of the furnace was observed.
(6) The humidity of the air used as  the carrier gas was very high, resulting in fre-
quent replacement of the dehumidifying silica gel.
(7) The performance of dust filter in front of the infrared analyzer was poor. Thus
it was replaced by a glass wool filter which caused a new trouble of condensation of
moisture.
    Samples were taken from the scrubber of the continuous TOC analyzer, and
TOC was measured by  a laboratory-type TOC analyzer. Fig. 6 shows the compari-
son of TOC thus obtained  with that by the continuous analyzer. Fairly good corre-
lation is observed.
    Fig. 7 shows the comparison of TOC obtained by manual sampling and analysis
of primary and secondary effluents with that obtained by the continuous TOC at
the same  time.  The black circles and triangles in the Figure indicate total TOC
manually analyzed, and the white ones represent dissolved TOC manually analyzed.
    According to Fig. 7,  the continuous TOC analyzer gives data close  to  the
measurement of the dissolved TOC.  As to the primary effluent, suspended solids
removal is done by a  centrifuge as mentioned before. However, with regards to
other samples, no provision is made for SS removal except a coarse filter for removal
of larger materials.  Therefore, a considerable portion of SS seems to be removed in
the sampling and 1C removal system.
    Fig. 7 also  indicates  that the correlation  between dissolved TOC  by manual
analyses and TOC obtained from  the continuous TOC analyzer is worse than that
shown in  Fig. 6, implicating not only loss of SS in the sampling system but also a
possible change of water quality in other form may exist.
    The TOC analyzer of this type is considered most appropriate for water  sample
containing high SS among the continuous TOC analyzers currently on the market.
However, at this stage it can be concluded that the continuous measurement of total
TOC is not practicable.
                                     207

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Fig. 6 Comparison of TOC, Manual and Automatic Analyses
      - Samples taken at the outlet of the scrubber in the TOC monitor -
                                                    50
                     TOC, Automatic Analysis (mg/S)
       Fig. 7 Comparison of TOC, Manual and Automatic Analyses
                                                 A A  Primary Effluent

                                                 O •  Secondary Effluent

                                                 D    Filtered Secondary Effluent
                                            ,• and A refer to Total TOC
                                             manually measured.
                20       30       40
               TOC, Automatic Analysis (mg/8)
50
         00
                                208

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3.2  CONTINUOUS UV PHOTOMETER
    Most of the organic substances bear the nature of UV absorbance.  Being based
on this principle, continuous UV photometer is sold on the market as a organic
content monitor.
    The correlation between UV absorbance and TOC of various kinds of sewage
was investigated extensively by laboratory analyses. It was found that comparative-
ly good correlation was seen when water  sample was  of the same type.  Therefore,
continuous UV photometers were installed at the Nishiyama Demonstration Plant
and Toba Pilot Plant for the field evaluation.
    This continuous UV photometer measures the extinction of 254 nm UV beam.
The turbidity influence is corrected by taking the ratio of transmitted light intensi-
ties of ultraviolet and visible rays.  Soon after continuous operation was  started, it
was discovered that the  ambient temperature variation affected  the measurement
significantly.  The temperature  characteristic  of the  detector unit is described in
Fig. 8. Accordingly, the photometer was remodelled  to put the detector unit  in a
constant temperature box of*40°C. An activated carbon column was installed at the
exhaust  pipe of the constant temperature box to remove  ozone generated in the
box.

           Fig. 8 Effect of Ambient Temperature on UV Absorbance Measurement
                                      20                30                40
                            Ambient Temperature (°C)

     Fig. 9 shows the relationship between UV absorbance and TOC (value obtained
by continuous TOC analyzer) at the Nishiyama Demonstration Plant, which seems
relevant with the exponential function.
     Fig. 10  shows the  relationship between UV absorbance  and turbidity with
regards to primary effluent. Judging from  this figure, there is no correlation be-
tween them, therefore, the influence of turbidity seems to be compensated.
     Fig. 11 is the data obtained at the Toba Pilot Plant. Each datum represents an
average of 12 values obtained from analyses of 24 hours composite samples. Accord-
ing to Fig. 11, the data tendencies of activated carbon effluent and other effluents
differ slightly.  This may be because the residual organic compounds in the activated
carbon effluent  are composed  mainly  of those with no UV absorbance, such as
polisucroses.
                                     209

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   80-
   70-
   60-
   50-
8
Fig. 9  Relationship between UV Absorbance and TOC (Automatic Analyzer)

          [  A  Primary Effluent
   Legend  I  °  Secondary Effluent                          A        ^
          I  •  Secondary Effluent (Alum Addition)
          I  A  Filtered Secondary Effluent
                                                         A

                                                      A  A
                                                        ^
                                                     A A
   30-
   20-

   10-
                  0.5
                                 10
                                 UV Absorbance
                                                                               l.'S
                                                                                                       2o

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Fig. 10  Effect of Turbidity on UV Absorbance - Samples are primary effluent.
              80
              70-
              60
              50--
              40
              30
                           0.5
                                      l.O
                                   UV Absorbance
                                                  1.5
                                                             2.0
    Fig. 11  Relationship between UV Absorbance and TOC, Toba Pilot Plant

                                ST:  Secondary Treatment
                                F:   Filtration
20

15

c*
1 10
o
o
5

C
CC: Chemical Clarification
AC: Activated Carbon Adsorption
a
a
A

0 <9
D ST + F
A ST + CC + F
n ST + F + AC or
ST + CC + F + AC
0.1 0.2 0.3 0.4 0.5
UV Absorbance
                                    211

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3.3   AUTOMATIC  SV AND SVI METER
     SV and SVI are useful indexes for operation and maintenance of the activated
sludge process.  A couple of SV and SVI  meters are already on the market.  Fig. 12
shows an example of a block diagram.  The mechanicms of each SV and SVI meter
is virtually the same.
     After air lifting  the water sample from the aeration tank into the settling tube
of 170mm  in  inside diameter,  MLSS is first  measured by the  SS meter of the
scattering light  method with air being injected from  the bottom for mixing. The
meter reading is registered in the memorizing unit.
     Next the stirring is stopped, to conduct SV measurement.  Light source and
photo cell installed outside  the settling tube are  descended by a motor until the
transmitted light intensity becomes lower than the fixed level, thus the light source
and the photo cell follow constantly the position  of the sludge level.  The SV value
is detected by the potentiometer, connected to the motor, 30 min. after the start of
settling. Based on these MLSS and SV measurements, SVI is computed electrically.
At each measuring time, the inside of  the settling  tube is cleaned automatically by
a brush to prevent interference by stain.

                    Fig. 12 Block Diagram of SV and  SVI Meter
                                 Leaf Chain
            Brush Rotating Motor (    U
                                                   Brush Shaking Motor
                                                  Potentiometer
                                    212

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    The SV and SVI  meters are  actually in use at many sewage treatment plants
and are generally working well.  Figs.  13 and 14 shows the comparisons of SV and
MLSS  obtained by an automatic meter and manual analyses at a sewage treatment
plant in Aichi Prefecture. The figures indicate that both values agree fairly well.
    It was observed,  however, that color of the  sewage sometimes effected the
MLSS  or the SVI measurements. Therefore, modification  of the meter by mounting
another SS meter on the top-side of the settling tube is being investigated in order to
correct the effect of color variation.

              Fig. 13 Comparison of SV, Manual and Automatic Measurement
                                     15          20
                                 SV, Manual Measurement (%)
             Fig. 14 Comparison of MLSS, Manual and Automatic Measurements
                             1000    1500    2000    2500
                                 MLSS, Manual Analysis (mg/8)
                                       213

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3.4   AUTOMATED COLORIMETRIC ANALYZER  FOR PHOSPHORUS
     At the Nishiyama Demonstration Plant, continuous measurement of dissolved
hydrizable  phosphorus in  primary and secondary effluents is carried out for the
purposes of mole ratio  control of chemical addition and others. The  measuring
device basically is the same as the automated colorimetric analyzer for ammonia,
which was reported at the 4th conference, except that it uses a filter paper for filtra-
tion and a hydrogen peroxide solution for cleaning.
     The measuring device, installed in December,  1976, has been operated for
several months. This device has an automatic calibration mechanism, and it assures
certain level of accuracy.  Data obtained by the automatic analyser agreed well with
those attained by manual analyses. However, the device developed  a number of
mechanical troubles as listed below, leaving room for further improvement.
(1)  For some reasons, when the flow ratio of sample and reagents or that of sample
and air for separation is destroyed,  unusual color development occurred.
(2)  The filtration of sample  water  is conducted continuously  by  using a filter
paper. The filter paper, after use,  tore occasionally.  Leakage of water at the filter
sometimes caused entrance of suspended solids into the  filtrate.  The  back flushing
of sulfuric  acid caused by back pressure opened holes in the filter paper.  Various
attempts are being made to correct  these defects, but substantial changes are deemed
necessary.
(3)  In order to prevent formation of slime in the tubing,  hydrogen peroxide solu-
tion was used for cleaning. But it was discovered that  scales, which  could not be
removed  by hydrogen peroxide solution, were formed inside the mixing coil. As
these scales can  be removed  by  sodium hydroxide solution, hydrogen peroxide
and sodium hydrate  solutions are used in turn to  clean the tubing. However, alka-
line solution causes unusual color development, so  that it  takes a long time to restart
the normal operation.
(4)  When  replacing  the  pump tube,  sample water, containing  sulfric acid, back
flowed due to internal pressure and wetted often  the operators and the instrument.
3.5   OTHER MEASURING INSTRUMENTS
3.5.1   AUTOMATIC CLEANING  UNIT FOR DISSOLVED OXYGEN
       ELECTRODE
     When measuring dissolved oxygen in the aeration tank, it is important to pre-
vent the formation of slime on the electrode surface.  Recently, an automatic clean-
ing system employing air jet  was introduced.  Fig. 15 shows this new cleaning
system. Type-A  unit is designed to measure dissolved oxygen when flow velocity
is insufficient for DO measurement.  At measuring time, the air, from the upper air
injection port, pumps up water to  accelerate the velocity. And at cleaning time, the
air is injected  from  the lower air injection port and clean  the electrode surface by
vigorous aggitation.
     Type-B unit is for the occation that the flow velocity  is sufficient for the DO
measurement.  It  has large  openings at the  position of the DO  electrode for the
water to pass through and has only  an air injection  port for cleaning.
     The effectiveness of this unit has been proved  by field tests.
                                    214

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                   Fig. 15 DO Probe with Air Injection Cleaning System
                     Type A
Air Injection Port
    for Air Lift

     DO Probe
Air Injection Port ^
   for Cleaning
                      Temp. Signal Cable
                         Temp. Detector

                        Air Supply
Air Supply
                    Sample Suction Port
                     DO Signal Cable
                                       Type B
                                         / Cleaning Air Supply

                                            Temp. Signal Cable
                        Temp. Detector
                            DO Probe
                                                Air Injection Port
                                                   for Cleaning
                                                     DO Signal Cable
 3.5.2  ULTRASONIC WAVE SLUDGE DENSITY  METER
      An ultrasonic wave sludge density meter is installed at the Nishiyama Demonst-
 ration Plant.  The meter, for the  past  two years,  is continuously  measuring the
 concentrations of primary  sludge, excess sludge and return sludge.  The sludge
 concentration agreed well with those attained by manual measurements. Especially,
 good results have been obtain with regard to excess sludge.
      However, the variation in the sludge composition seems to pose some problems.
 To obtain good results in the measurement of the primary sludge, it is necessary to
 increase the frequency of calibration.
 3.5.3  SLUDGE  LEVEL METER
      Sludge level meter, especially ultrasonic-meters,  are  becoming  widely used at
 various sewage treatment plants for automatic sludge withdrawal control systems.
                                        215

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                        FIFTH US/JAPAN CONFERENCE
                                   ON
                       SEWAGE TREATMENT TECHNOLOGY
                              PAPER NO, 5
STUDIES ON ADVANCED WASTE TREATMENT
           APRIL 26-28, 1977
             TOKYO., JAPAN
        MINISTRY OF CONSTRUCTION
          JAPANESE GOVERNMENT

                  217

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  STUDIES  ON ADVANCED  WASTE TREATMENT
I. UPGRADING OF EXISTING SEWAGE  TREATMENT  PLANTS
  BY CHEMICAL ADDITION TO  AERATION  TANK	220
     T. Annaka, PWRI, Ministry of Construction
2. DEVELOPMENT OF DEEP AERATION TANK	237
    Dr. N. Okuno,  Japan Sewage Works Agency
3. EXPERIMENTAL STUDIES ON PERFORMANCE  OF RAPID
  SAND FILTRATION PROCESS  FOR TERTIARY  PURPOSE	-249
    H. Fujii, Tokyo Metropolitan
    S. Kyosai, PWRI, Ministry of Construction
4. EXPERIMENTAL STUDY ON REGENERATION OF  GRANULAR
  ACTIVATED CARBON  	324
    S. Ando,  PWRI, Ministry of Construction
                            218

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CHAPTER 1.   UPGRADING OF EXISTING SEWAGE TREATMENT PLANTS
              BY CHEMICAL ADDITION TO AERATION TANK
1.1   Introduction	220
1.2   Outline of Facilities and Testing Procedure 	220
  1.2.1  Coagulant and Dosing Procedure  	222
  1.2.2  Sampling and Analysis	222
  1.2.3  Automatic Continuous Water Quality Analyzers  	222
1.3   Results and Discussion	222
  1.3.1  Removal of Phosphorus	225
  1.3.2  Nitrification and Nitrogen Removal	228
  1.3.3  Acceleration of Nitrification by PH Adjustment	 230
  1.3.4  Organic Removal 	232
  1.3.5  Suspended Solid Removal	232
  1.3.6  Effects on Microorganisms	233
  1.3.7  Material Balance of Sludge Production	234
1.4   Costs of Chemicals	236
1.5   Summary  	236
                                  219

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1.  UPGRADING  OF  EXISTING SEWAGE TREATMENT PLANTS
    BY CHEMICAL ADDITION TO AERATION TANK
1.1  INTRODUCTION
     In Japan there are not yet any national water quality standards established for
nitrogen  and phosphorus.  However, eutrofication is  advancing  in  an increasing
number of lakes, bays and other waters. It is therefore presumed that a substantial
number of sewage treatment plants will be required in the near future to install
themselves with facilities for removing phosphorus, nitrogen. But in our country it
is considered extremely difficult, in many cases, to build additional facilities in the
existing sewage treatment plants due to difficulty in securing tracts of land, although
the situation is different in the case of newly planned plant.
     This is the reason why attention is being focused into the method to upgrade
the existing  plants by adding metal salts  to  the existing facilities such as aeration
tank. This method has already been in practical use in the Great Lakes region of the
United States and some parts of Europe. But  the situation in Japan is somewhat
different from others;  the  strength  of sewage  is weak. On the average, domestic
sewage in  Japan contains  150 mg/C of BODS, 3-4 mgP/C of T-P, 30  mgN/£ of T-N
and 100 mg/C of total alkalinity as CaCO3.
     The Public  Works Research Institute, the Ministry  of Construction, in col-
laboration with the Sewage Works  Bureau of of Nagoya  City, has been operating
Nishiyama Sewage Treatment Plant  in the city for two  years for experimental pur-
poses. Since  then, experiments have been carried out by an addition of alum to the
aeration tank to determine the effect of the alum addition on the entire functions of
the treatment facilities.  The results in the initial stage were reported at the previous,
4th conference. This report covers the performance in the ensuing period.
1.2  OUTLINE  OF FACILITIES AND TESTING PROCEDURE
     The Nishiyama Plant is a relatively  small sewage treatment plant adopting
a separate sewer system, having a design daily average  flow  of 20,000m3/day
(30,000 m3/day at maximum).  Since the plant's served area is a  residential  area,
incoming loadings fluctuate widely at times. There is no recycling of digester super-
natant and other wastes from the sludge treatment facility, because sludge is treated
at  a separate plant. The  conventional activated  sludge process is  adopted  in the
secondary  treatment facility. Two bays - an alum bay and  a control bay are used to
compare their performance. There are three final sedimentation tanks. At the first
two months, two  of them were used one for the each bay. But they  are now being
used in a rather irregular manner -  two on one and one on the other, to ensure the
better quality of the plant effluent.  The flow chart of the plant is shown in Fig. 1.1
and the dimension of the plant in Table 1.1.
                                    220

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                          Fig. 1.1  Flow Diagram of Nishiyama S-T-P
            Grit
          chamber
                       Pre-
                       aer-
                       ation
                       tank
           Sewage	Sludge
    MM  Pump

    ( Pj  Flow meter

    (SM)  Sludge Density Meter

    MM  Turbidimeter


    (M)  Point of Continuous
          Monitoring for, P, NH3 -N
          UV.andTOC.
L —(n (^5MWxl-/f>\--J
                           Table 1.1 Outline of Nishiyama Facilities
^\ Item
Facility ^\
Grit
chamber
Preparation
tank
Primary
settler
Aerator
Final settler
Type
Rectangular
Diffused
aeration
Rectangular
Diffused
aeration
2 storied
rectangular
Dimension (m)
W L H
2.5 x 10 x 1.85
4.0 x 20 x 3.5
5.0 x 28 x 30
5.0x40x 50x2 bay
«"££'"
Number
2
1
4
2
3
Total
volume
(m3)

245
1,680
4,000
2,250
Design
detention
time
1 .2 min.
1 .3 min.
1.3hr.
3.2 hr.
l.Shr.
Notes:  1.  Influent coming in by gravity.

        2.  Sludge is being treated at the adjacent plant.
                                             221

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1.2.1   COAGULANT AND  DOSING PROCEDURE
    The coagulant used is liquid alum (A12(SO4)3 • 18H2O) containing about 8 per
cent of A12O3. It is dosed at the end of the aeration tank,  and the dose rate is
controlled to maintain  the concentration of Al at the set level  by use of a pro-
portional pump. During the operational period of  about  16 months, the dose con-
centration was from 8 to 6, 4, 3 mg/C of sewage in terms of Al (from about 100 to
75, 50, 32 mg/C of sewage in terms of alum).  During this period, the concentration
of phosphorus in the primary  effluent changed from 2 to 7 T-Pmg/£ in the daily
average. The mole ratio of Al to P also proved to vary widely.
1.2.2   SAMPLING AND ANALYSIS
    On a daily base, grab sampling is conducted every one or two hours by auto-
matic samplers and 24 hour composite sample is adjusted in proportion to the flow
rate.  Samples  are also  taken manually as needed.  Analyses are made two to four
times  a week.
1.2.3   AUTOMATIC CONTINUOUS WATER QUALITY ANALYZERS
    The plant is equipped with several types of automatic water quality analyzers
for continuous monitoring of the  water quality of both influent and effluent and
controls of the process.
    There are ultra-sonic sludge density meters (3 units), TOC meter (1  unit, 6
points), UV  meter (1 unit, 6  points),  turbidimeters (5 units), phosphorus meters (3
units), ammonia nitrogen meters (3 units), PH meters (6 units) and pre-treatment
units  for these analyzers. Their operational performance is reported in a separate
paper.
1.3  RESULTS AND DISCUSSION
    The survey has been held continuously since February 1975.  The  period of
survey,  excluding the first two months,  can be divided into seven experimental
phases by the rate of alum dose and dosing methods. In Phase II,  two of the three
final sedimentation basins were used for control bay, and after Phase III, two of the
three  basins  were used  for alum bay. This switch was  made  because of a rise of
MLSS in the alum bay which brought about massive solid wash-outs from the final
settler under heavy hydraulic loading period.  Summary of operational conditions in
each phase is shown in  Table 1.2.  In Phase V, alum was dosed  at a fixed rate deter-
mined by the  daily average flow in order to  test  the situation under which flow
proportional dose control is  not possible.  In Phase VIII, the point of addition of
alum  was moved  from  the end point to a point 3/4 of the entire length from the
inlet (20 m from the terminal and about 60 min. in aeration time).
    In  each phase, efforts were made to maintain  MLVSS of the two bays as close
as possible, but this was not necessarily being achieved. Especially in the control
bay, as temperatures went down, activated sludge began getting bulky, raising SS in
the effluent  and making it difficult to maintain MLSS of desired  level. In  general,
MLSS was kept at low levels due to a low strength of sewage and a  small capacity of
the final settlers.  The summary of the water qualities of influent and effuent in
Phase  II, IV,  VI and VII is shown in Table 1.3.
                                    222

-------
                            Table 1.2  Summary of Operation
^•x^--— ^Phase
\\ >o~^~^
\\*
\5^
Item \
Flow rate
(m3/d)
Detention time
(hr)
MLSS (mg/fi)
MLVSS (mg/8)
MLVSS/MLSS
(%)
SV1
BOD load
(kg/kg/d)
SRT (d)
Settling time
(hi)
Over flow rate
(m3/d/m2)
Alum dose
(mg/Al/2)
II
1975.4.1
-9.21
Con-
trol
Alum
11,950
3.0
1,025
719
70.1
94
0.41
3.2
3 6

23.8
-
3.0
912
589
64.6
112
0.46
1.9
1 8

47.6
8
III
9.22-10.19
Con-
trol
Alum
12,550
2.9
1,403
946
67.4
76
0.21

1 7

50.0*
-
2.8
1,002
634
63.3
89
0.29

3 4

25.0
8
IV
10.20-
1976.1.7
Con-
trol
Alum
11,700
3.2
768
620
80.7
115
0.64
3.0
1 8

46.8
-
3.0
1,546
1,000
64.7
72
0.32
3.8
3 6

23.4
6
V
1.8-2.7
Con-
trol
Alum
9,800
3.6
765
673
88.0
136
0.68

2 2

39.2
-
3.4
1,496
1,136
75.9
76
0.35

4 3

19.6
4
VI
2.7-3.31
Con-
trol
*)
Alum
10,900
3.2
631
517
81.8
164
0.75
2.0
20

43.6
-
3.2
1,333
968
72.6
68
0.36
3.1
3 9

21.8
4
VII
4.1-6.30
Con-
trol
Alum
13,075
2.9
743
477
77.5
78
0.59
2.3
1 4

52.3
-
2.9
1,810
1,238
67.0
58
0.25
4.8
2.8

26.2
3
Yin **)
8.23-9.2
Con-
trol
Alum
13,600
3.5
659
432
65.5
96
0.41
2.3
1.5

54.4
-
3.5
1,231
737
59.8
61
0.23
4.3
3.1

27.2
6
*)  Constant feed  **) Point of dose was changed
                                          223

-------
Table 1.3 Summary of Performance









p
H
A
E

II














P
H
A

E
IV












L'
H
A
s
E
VI













P
ii
A
S
E
VII







PH
Turb.
SS
T-Alk.
T-BOD
S-BOD
T-COD
S-COD
T-TOC
S-TOC
TKN
NH3-N
NO2-N
N03-N
T-P
Ort-P
S-T-P
T-A1
E-Coli
ABS
PH
Turb.
SS
T-Alk.
T-BOD
S-BOD
T-COD
S-COD
T-TOC
S-TOC
TKN
NH3-N
NO2-N
N03-N
T-P
Ort-P
S-T-P
E-Coli
ABS
PH
Turb.
SS
T-Alk.
T-BOD
S-BOD
T-COD
S-COD
TKN
NH3-N
NO2-N
NO3-N
T-P
Ort-P
S-T-P
ABS
PH
Turb.
SS
T-ALK
T-BOD
S-BOD
T-COD
S-COD
T-TOC
S-TOC
TKN
NH3-N
N02-N
NO3-N
T-P
Ort-P
S-T-P
Ecoii
ABS
Unit

mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
N/ml


mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
N/ml
mg/1

mg/I
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1

mg/1
mg/1
mg/i
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/I
mg/1
mg/1
mg/1
mg/1
mg/I
N/ml
mg/I
Influent
Ave.

93.8
110
77.3
87
40
59
23
72
30
24.9
13.4
0.034
0.053
3.43
2.14
2.18
0.81

6.51

61.0
128
81.3
133
47
64
20
75
23.
26.0
13.7
0.023
0.25
3.15
1.92
1.71

6.25

98.5
214
92.3
182
62
87
30
29.8
14.9
0.03
0.08
4.43
2.61
2.35
6.46


141
66.8
108
40
61
17
63
20
22.8
10.2
0.07
0.13
3.50
1.67
1.79

4.8
Range
6.88-7.30
67.0-132.0
60-114
60.0-106.5
47-124
26-69
44-90
17-35
39-122
20-51
21.8-28.7
10.2-15.9
0.00-0.28
0.00-0.23
2.14-4.92
1.38-4.15
1.13-3.66
0.56-1.20

5.10-8.50
6.70-7.12
50.0-72.0
90-174
59-104
97-168
39-57
50-83
16-28
42-110
12-32
24.2-34.6
12.0-14.6
0.00-0.05
0.00-0.82
2.06-48.8
1.57-2.10
1.41-2.0

4.6-7.7
7.0-7.27
79.0-120.0
56-471
82-99.5
151-210
48-69
72-120
21-45
25.0-35.5
13.6-15.5
0.01-0.05
0.00-0.23
4.00-5.24
1.97-4.12
2.18-2.58
5.45-7.40
6.87-7.0

96-192
55-80
88-149
23-53
47-76
14-20
53-69
13-24
14.6-32.1
6.0-12.9
0.00-0.22
0.07-0.32
2.92-4.06
1.25-2.03
1.10-2.23

2.5-9.5
Primary Effluent
Ave.

72.0
40
88.7
54
35
43
24
53
28
24.0
13.8
0.009
0.037
3.05
2.16
2.16
0.50

6.06

39.1
42
89.1
79
46
47
22
52
23
23.7
15.0
0.01
0.133
3.00
2.04
1.71

6.37

51.7
45
90.6
82
52
57
30
25.5
16.2
0.04
0.04
3.44
2.11
2.35
5.83

48.7
45
77
68
35
38
18
41
19
20.0
11.7
0.05
0.10
3.04
1.81
1.88

4.4
Range
6.86-7.60
52.0-92.0
36-73
75.5-135
32-95
23-63
27-74
15-30
38-87
16-51
19.9-39.1
10.1-25.5
0.00-0.04
0.00-0.15
2.01-7.90
1.36-4.40
1.22-6.16
0.30-0.80

5.18-7.50
6.86-7.20
36.0-42.1
34-49
79.3-94.5
64-102
38-60
38-60
17-31
25-71
12-32
21.0-28.2
13.2-16.5
0.00-0.02
0.00-0.41
1.86-3.86
1.74-2.39
1.53-1.98

5.4-7.3
7.0-7.18
49.0-54.0
27-54
88-93.5
75-88
42-64
48-76
21-41
21.3-28.8
14.6-18.0
0.03-0.04
0.00-0.13
2.84-3.81
1.89-2.30
2.04-2.86
5.20-6.40
6.90-7.0
28-100
22-84
68-87
62-96
23-48
29-53
13-35
26-48
13-22
14.5-23.0
8.0-14.8
0.00-0.13
0.05-0.15
2.73-3.58
1.53-2.28
1.26-2.51

2.5-6.0
Final Effluent
(Control)
Ave.

8.0
8.5
36.8
10.9
5.1
14.0
10.4
17.6
13.6
10.2
7.1
0.581
4.10
1.51
1.12
1.09
0.26
2700
0.40

8.0
12
55.4
22.7
4.7
12.9
9.1
18.4
9.7
15.0
11.3
0.243
3.03
1.93
1.17
1.32
5100
0.67

8.5
16.2
87.5
16.3
5.3
15.3
9.6
23.1
14.8
0.06
0.20
1.83
1.60
1.51
0.59

10.5
13
46
26
7.2
13.8
8.6
13.9
9.5
11.9
8.0
0.29
1.99
1.68
1.11
1.12
1800
0.54
Range
6.26-7.60
4.1-11.3
6.2-12.4
12.0-95.0
6.5-19.5
2.9-8.4
9.3-16.4
5.1-14.6
12.0-36
9.4-29.5
5.0-21.0
2.8-17.4
0.06-1.26
0.19-8.50
0.67-3.21
0.59-1.97
0.46-2.40
0.25-0.30
200-9600
0.22-0.58
6.50-7.10
7.6-9.5
6-20
23.4-84.5
1 12-28
2.2-6.4
10.1-15.1
6.8-10.8
6.2-34
4.3-15.0
6.9-20.2
5.4-15.3
0.12-0.30
0.18-6.45
1.29-2.73
0.18-1.58
1.05-1.47
2500-7000
0.25-0.90
7.06-7.23
5.7-7.0
6.8-32.0
82-94.5
12.1-23
4.7-5.8
12.9-21
7.5-12.7
15.1-30
13.4-17
0.02-0.10
0.00-0.32
1.63-1.9
1.43-1.82
1.35-1.61
0.52-0.66
6.65-6.96
3.4-50.3
4-21
30-69
14-34
6.3-8.8
11.2-16.7
6.8-10.5
11-17
8.3-10.9
8.6-17.9
5.2-13.7
0.22-0.54
0.10-3.89
1.13-2.27
0.36-1.74
0.18-1.82
480-4500
0.26-0.99
Final Effluent
(Alum)
Ave.

7.4
15.0
31.7
7.0
3.4
9.8
6.6
13.4
10.5
16.4
13.1
0.086
0.653
0.355
0.185
0.087
0.86
2000
0.68

4.1
4.7
48
4.5
2.8
7.9
6.1
10.9
6.6
17.1
14.5
0.035
0.488
0.168
0.093
0.045
500
0.575

5.3
13.9
73.8
8.5
4.7
12.4
8.6
20.0
15.9
0.06
0.16
0.52
0.27
0.19
1.34

6.8
11
61
12
6.1
12.3
7.2
10.8

15.2
10.7
0.09
0.71
1.09
0.61
0.40
840
0.58
Range
6.62-7.3
4.9-11.6
4.0-57.0
13.5-42.5
3.6-12.8
1.3-5.2
8.2-18.9
5.1-11.1
8.0-22.3
7.7-21.0
9.8-20.3
10.0-16.4
0.01-0.32
0.12-1.41
0.14-0.69
0.06-0.60
0.02-0.25
0.39-1.30
180-8500
0.30-1.30
6.70-7.02
3.2-5.0
0.2-12.3
40-56
2.5-6.9
1.9-4.6
6.2-10.6
4.7-6.9
4.0-17.0
3.5-9.0
14.2-20.4
12.3-16.5
0.02-0.08
0.07-0.83
0.14-0.21
0.05-0.19
0.01-0.09
30-1800
0.24-0.80
7.07-7.10
3.7-7.0
6.0-28
67.5-82
7.4-9.3
4.3-4.9
10.4-19
5.7-13.1
15.2-24
13.9-18
0.03-0.09
0.00-0.25
0.37-0.72
0.09-0.69
0.03-0.29
0.84-1.76
6.73-7.04
2.2-28.1
6-13
50-67
6-16
5-8
10.5-14.1
6.3-8.6
9.0-12.0

11.0-20.3
7.6-14.5
0.08-0.22
0.11-1.27
0.53-1.96
0.17-1.45
0.02-1.53
200-1800
0.3-0.78
Removal Eff.
Over Secon-
dary (%)

88.9 89.8


80.0 87.2
85.3 91.2
67.2 77.0
57.4 73.0
67.0 74.9
50.0 62.1
57.5 61.7
48.6 5.1


50.5 88.4
48.2 91.5
49.6 96.0


93.4 88.8

78.1 89.6
71.1 94.3

71.1 94.3
89.7 95.9
72.6 83.2
50.5 72.2
64.7 79.1
57.5 71.9
32.8 27.9
24.7 3.4


35.4 34.4
42.7 95.5
22.9 97.4

89.5 91.0

85.6 89.8


80.1 79.6
89.9 91.1
73.1 70.2
67.6 71.0
9.5 21.6
8.7 1.9


46.9 84.9
24.2 87.3
35.8 92.0
89.9 77.1

78.5 86.1
71.1 75.6

61.8 82.4
79.5 82.6
63.7 64.9
52.3 60.0
66.1 73.7

41.5 24.0
31.7 9.6


44.8 64.2
38.7 66.3
51.5 79.8

87.8 86.9
              224

-------
1.3.1   REMOVAL  OF  PHOSPHORUS
a.   Phosphorus Removal and Mole Ratio
    Phosphorus removal rate is raised drastically by an addition of alum. Table 1.4
shows the phosphorus removal efficiency in each phase. Fig. 1.2 shows relationships
between the mole ratio of dosed Al to soluble phosphorus and residual phosphorus
in effluent.


                     Table 1.4 Summary of Phosphorus Removal
~r - — — -____ Phase
Item 	 	 — . 	
Primary Eff. T-P (mg/£)
Primary Sol. T-P (mg/£)
A£ Dose (mg/£)
A£/P Mole Ratio (T-P Base)
A£/P Mole Ratio (ST-P Base)
Effluent T-P (mg/£)
Effluent Sol. T-P (mg/fi)
II
3.05
2.16
8
2.98
4.25
0.355
0.087
III
2.15
1.28
8
4.25
7.18
0.27
0.09
IV
3.00
1.71
6
2.29
4.03
0.168
0.045
V
3.04
1.95
4
1.49
2.35
0.53
0.17
VI
3.44
2.35
4
1.38
1.95
0.52
0.19
VII
3.04
1.99
3
1.16
1.74
1.09
0.40
VIII
2.29
1.52
6
3.01
4.53
0.42
0.03
Note:  All values are average through the each phase.
                        Fig. 1.2 Residual Phosphorus V.S.
                               AI/P Mole Ratio (S-T-P Base)
             I.O
          "SB
          &
          ST  0.5
                                                   oT-P
                                                   • Sol. T-P
                                 345
                                    Mole ratio
7   (Al/P)
     The residual phosphorus  is 0.5 mgP/£ in T-P and below 0.2 mgP/£ in soluble
T-P in phases other than Phase VII in which the mole ratio was low. Fig. 1.2 shows
that if the mole ratio  is above 2 (Al 4 or alum  about 50 mg/£), effluent soluble
phosphorus can be decreased below 0.2 mg/£.
                                     225

-------
     The residual phosphorus is 0.5 mg P/l in T-P and below 0.2mg P/l in soluble
 T-P in phases other than Phase  VII in which the mole ratio was low.  Figure 1-2
 shows that if the mole ratio  is above 2 (Al 4 or alum about 50mg/l), effluent
 soluble phosphorus can be decreased below 0.2mg/l.
     Effluent PH varies with the rate of alum addition in the range from 6.6 to 7. It
 is not wise to dose  alum at a mole ratio of more than  4,  since the solubility of
 A1PO4 is 0.01 mgP/C at PH6 and 0.3  mgP/C  at  PH7.  However, as for total phos-
 phorus removal a higher mole ratio  seems to be effective in regards to floe forma-
 tion. In the treatment of domestic sewage in our country  where the daily average of
 phosphorus concentration is 3 ~ 4 mgP/C, an alum dose rate of 50 ~ 70 mg/£ would
 be enough to lower T-P below 0.5 mg/£ and soluble  phosphorus 0.2 mg/£.  Inci-
 dentally, at  this particular sewage treatment plant, the phosphorus removal rate in
 the control bay is rather high with 40% ~ 50% probably  due to a luxury uptake of
 bio-mass.
 b.   Phosphorus Removal Capability of Return Sludge
     By  an alum  addition, the return sludge proves to remove (absorb) a substantial
 amount  of phosphorus  from the influent.  Fig.  1.3 shows a comparison of hourly
 changes  in the phosphorus concentration of superatant of the mixed liquer immedi-
 ately after return sludge was mixed with the influent in both control and alum bays.

              Fig. 1.3 Diurnal Change in ST.P. of Mixed Liquor Supernatant
                                                   Control
                                                   Alum
                                               18  (hr)
(Phase IV) In this  instance, a contact with return  sludge removes about 80% of
phosphorus. This is  considered to be absorption of aluminum hydroxide contained
in return  sludge. Fig. 1.4 shows the results of a jar test in which the mixing ratio
of return sludge  and influent was changed in order to ascertain phosphorus removal
capability.  As the mixing ratio is raised, as shown in the figure, the rate of removing
soluble phosphorus  from  the superatant will increase, and the removal rate reaches
90% when MLSS is above 3,000 mg/C  (Al concentration of sludge  10% Al/TS).
                                     226

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A  similar test was  conducted using alum sludge  yielded in the water purification
plant.  Aluminum in sludge was 12.5% Al/TS.  Fig. 1.5 shows the  results of the jar
test. As in the case of return sludge, a high phosphorus removal rate is attained with
the alum  sludge  of  the purification plant. This indicates an important  role that alum
sludge could play in removing phosphorus within the treatment process.

                     Fig. 1.4 P Removal Capability of Return Sludges
           100 .
         -a
         E
         £  50 -
                                                                       o
O Return sludge (Alum bay)

•  Return sludge (Control)

A Alkalinity (Alum)
 Initial?: 1.8mg/S
                              1,000
                                              2,000
                                          MLSS(mg/S)
       3,000
                        Fig. 1.5 P Removal Capability of
                               Alum Sludge Yielded at Water Plant
               i oo
                50-
                                              0 S-P removal rate
                                                Initial?: 1.39 mg/e
                                                                    -7.0
                                                                    -6.0
                                 1,000
                                                 2,000
                                                                  3,000
                                      MLSS (mg/2)
                                        227

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     Similar phenomena are observed in  the  pilot plants  in Yokosuka and Kyoto
treating secondary effluent with alum. They have stably attained a high phosphorus
removal rate by returning sludge to the head of the plant.
     As earlier stated, in Phase IV alum was dosed not in proportion to the inflow
but a constant rate. As shown in Table  1.4, there seems little difference in phos-
phorus removal efficiency between flow proportional feed control and constant feed
of alum.  This indicates that the "secondary" phosphorus removing capability perti-
nent to return sludge plays an important role in overall phosphorus removal.  In
adding alum to the aeration tank, it would be more efficient and costly to use waste
activated sludge from the alum bay for return sludge in other bays.
     The Nishiyama plant is in the initial stage  of practicing  the mole ratio feed
control by use of signals from automatic continuous phosphorus analyzers. If the
phosphorus removal rate is determined by the mole ratio of phosphorus in the super-
atant of mixed liquer at the point of addition, phosphorus removal capability of re-
turn sludge could be significant and  affect  the mole ratio feed control itself when
influent phosphorus concentration is used as a base of P.
1.3.2  NITRIFICATION  AND NITROGEN REMOVAL
     In this project, removal of ammonia nitrogen by nitrification is just as import-
ant an objective as well as removal of phosphorus.
     Fig. 1.6  shows changes in ammonia nitrogen, nitrite and nitrate in effluent
of both bays as observed during a period from March  1975 to July 1976.

                     Fig. 1.6 Change in Nitrogen in  Final Effluent
        30-,
         5-
                                            Water temp.
                                          '    fN02+N03)-N, control |j  V   >A
Mar.  Apr. May  June  July Aug. Sep.  Oct. Nov.  Dec.
                 1975
                                                    Feb. Mar.
       1	1
Apr.  May  June July
1976
                                     228

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     SRT was maintained in the range of 2 ~ 5 days. In both bays nitrification did
not take place in winter when temperature was low, probably because SRT was
not enough. In  Phases II ~ IV  in which temperatures were above 20°C, substantial
nitrification took place only in the control bay, while nitrite and nitrate nitrogen
was slightly observed in the alum bay.
     The absence of nitrification in the alum bay has been discussed from various
angles; first, SRT required to maintain nitrifiers; second, interference of aluminum
on the activity of nitrifiers; and  third, depletion of alkalinity.
     As to the interference  of aluminum  on  nitrification, batch type laboratory
tests show that an addition of  10 mgAl/£ (120 mg/C of alum) causes no noticeable
affect.
     The fact that in Phase VII  in which SRT is maintained higher (4.8 days), nitrifi-
cation took place even in the alum bay seems to indicate that SRT has a large effect
on nitrification, in conjunction  with the effect of temperature. This, however, seems
to have some relationships with a relatively low alum dose  rate, which means a low
consumption of alkalinity by alum  addition.  The nitrification of Nl  consumes al-
kalinity by 7.1 (as CaCOs).  The influent of this plant shows an daily average T-N
value of more than 25 mgN/£ and the alkalinity is a high 80 mg/£. Complete nitrifi-
cation, therefore, could not be  expected without an addition of alkalis, even if other
conditions are satisfactory.
     Fig. 1.7  shows how  the nitrogen, the PH and the alkalinity  of the superatant
of the mixed liquid will change as it flows down through the tank in  the alum bay
(Phase VII).  In this  instance  of low loading night hours, the  concentration of
ammonia nitrogen is low. But complete nitrification does not take place as alkalinity
is consumed by nitrification and alum addition.

                  Fig. 1.7 Change in  Supernatant Quality in the Aerator
                         (Alum Bay)
                                                    O PH
                                                    •  T-alkalinity
                                                    A NH3-N
                                                    O  (N02 +N03)-N
                                       Flowing time in aerator (hrs)
                                                                   Alum Outlet
                                                                   dose
                                      229

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     Thus  as in the case  of non-chemical addition, the lowering in water temper-
ature causes a problem in  nitrifying the effluent in the alum bay, as shown in Fig.
1 6  Therefore to keep desirable  SRT is a major factor in conjunction with the
capacity and structural improvement of the final sedimentation basin. It is also clear
that complete nitrification cannot be achieved without adding alkalis in place where
alkalinity is low, like the domestic sewage treatment of our country.
     In the case where nitrified effluent is obtainable, it is known that fine scum
appears to the surface of the  final settler as  a result of the generation of nitrogen
gas by denitrification  at the bottom of the settler. Through the experiment, it was
observed during the nitrificastin in the control bay. An experiment in resettling
by spraying of the effluent has been conducted. Since scum often flows out with the
effluent, the installation of a scum collector is under consideration.
     On the other hand, in Phase VII in which  nitrification took place in the alum
bay, the scum as mentioned above does not float at all and the surface of the settler
is clear in the  final settler, even if the level of oxidized  nitrogen in the effluent is
the same as that in  the control level. There seem to be factors hampering denitrifi-
cation in the alum dosing process.
     In ordinary cases, at  the plants where ntrification is taking place, there appear
differences between the inflow and outflow of T-N, which results in a relatively high
T-N removal rate probably due to  denitrification. The T-N removal rate is generally
lower in the alum bay than in the control bay  even when same degree of nitrifica-
tion is taking place. This is considered to have something to do with preventing the
 floating of scum.
 1.3.3  ACCELERATION OF NITRIFICATION  BY PH ADJUSTMENT
     As mentioned  earlier, when alum is added, it consumes alkalinity and prevents
 complete nitrification. Therefore, alkalis, such as sodium hydroxide and lime, need
 to be added in order to remove phosphorus and nitrify  the effluent simultaneous-
 ly in the system. There, it is difficult to use lime because of scale formation in pipes
 and other places.  Therefore,  sodium  hydroxide will  probably be  better  to be
 adopted for the purpose.
     A bench scale laboratory test was conducted prior  to the addition of sodium
 hydroxide to the main plant. About two months of operation demonstrated that it
 is  possible to obtain an almost completely nitrified effluent by adding alum  at the
 end section of the tank and sodium hydroxide at the inlet. Table 1.5, 1.6 show the
 operating  conditions  of the bench  scale plant and the qualities of the influent and
 effluent.  Almost complete nitrification and  a  T-N removal rate of about  70% are
 achieved by maintaining SRT  at 8.2 days and PH at the inlet at 8.2. The problem of
 this process seems to be a somewhat low phosphorus removal rate due to rises in the
 PH of the  effluent.
                   Table 1.5  Summary of Bench Scale Plant Operation
Flow
(m3/d)
2.5
Al Dose
(mg Al/B)
= 4
Adjusted
PH
8.2
MLSS
(mg/C)
3.030
BOD Load
(kg/kg/d)
0.17
SRT
(d)
8.2
                                      230

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                 Table 1.6 Summary of Bench Scale Plant Performance

Inf.
Efl.
Average
Range
Average
Range
PH
6.6-7.2
7.3-7.6
T-alkalinity
(mg/ECaCO3)
66
57-104
93
88-102
SS
(mg/E)
38
13-117
14
9-20
COD
(mg/E)
39
25-73
8
6-15
TKN
(mg/fi)
16.7
12-30
1.45
1.1-1.7
NH3-N
(mg/E)
8.3
6-11
0.26
0.14-0.40
NO2+NO3-N
(mg/8)
0.05
0-0.9
2.96
2.8-4.2
T-P
(mg/E)
2.66
1.56-5.15
0.78
0.5-1.2
     The  addition  of sodium  hydroxide  to  the actual  facilities  began in mid
December 1976. Since the aeration tank  is of a conventional plug flow type, the
caustic addition is controled at two points. One point is immediately after the mix-
ture of the influent with return sludge and the other at the middle  section of the
tank. Fig. 1.8 shows PH controls chart.

                            Fig. 1.8 PH Control Diagram
/NaOH\
V tank J
O
z
Control /T_3
valve ^T^

7
i

Controler




t

PH meter
-f
L
r




\ 	

Control valve
i£ NaOH


Buffle
Aeration tank
(S PH meter . .
v-' (1st point)
"~j Influent conduit
PH meter
^^ Moved point


f

^C


)
-••
O "" —
(2nd point)
PH meter
PH meter
     About  six weeks have passed since the caustic  addition began. The average
MLSS  concentration within the tank has kept 3,500 mg/5 (SRT approx. 8 days).
The  dose  rate of alum is 8 mg/C in terms of aluminum.  The addition of sodium
hydroxide (20% solution of NaOH) is controlled to raise PH at the first adjustment
point up to 7.8  ~ 8.0. At  the present stage, nitrification has not  taken place as
originally expected, because the water temperature is low - 10°  ~ 12°C and acclima-
tion to change in PH is insufficient.
     Two  problems have occurred as to the PH adjustment at the actual facilities.
One  problem is that PH  rises momentarily to about 12 in limited portions around
the inlet.  The second problem is that as a result of this, a sticky foam substances
appears to  the surface of the aeration  tank and that scum forms on the surface of
the final settler.
                                     231

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     The dose of soidum hydroxide is controlled using PH meters in the way that
the dosing  pump turns on  at the set  upper value (8.0) and turns off at the lower
value by the signals of PH  meters and  that the dose rate  is proportional to the in-
flow. There is a  15-minute  time lag between the dose of sodium hydroxide and the
response of the PH meter. This has been found to allow the dose of surplus sodium
hydroxide and raise PH around some portion of the inlet up to 12.
     A separately conducted indoor experiment shows that as PH exceeds 11, nitro-
gen in activated  sludge resolubilizes and foam formation develops. Also at the batch
test using return sludge of this treatment plant, as the PH of return sludge was raised
to 12 organic substances in activated sludge resolubilizes  into the superatant, such
high concentration as TOC of l,OOOmg/C and poly-saccharide of 600mg/£.  Thus,
it was considered that this might have been the reason of upset of the entire process.
     As a result, the point of sodium  hydroxide addition was moved to the upper
end of the  influent waterway (approx.  40  meters); the method was changed  to ad-
just  PH at  the tank inlet; and the outflow of  the dosing pump was changed to  a
constant rate.
1.3.4  ORGANIC REMOVAL
     The addition of alum raised removal rates for BODs, TOC and COD. To com-
pared with  control bay, the removal rate for BODs rose by 30%~80%, that for COD
20% ~ 40% and that for TOC 30% ~  40%. Similar results were attained for the re-
moval of soluble organic substances.
1.3.5  SUSPENDED SOLID  REMOVAL
     In  Phase II, effluent SS was higher in the alum bay. But it outrated that of the
control  bay after Phase III  in which two final settlers were used.  The debris of al-
uminum hydroxide floe tends to flow out more easily, in addition to rises in solid
loading  in the final settler. Therefore, it is necessary to provide a lower overflow rate
than the ordinary design value. It is observed that as the alum dose rate is lowered,
the density of the effluent SS tends to increase; this is probably because a decline
in the dose  rate will aggravate coagulation.
     In  Phase VIII in which the point of alum addition was moved to a point 3/4 of
the entire length (20 meters from the end), the effluent  became a little bit milky
white as time passed,  although there were no noticable differences in the SS value
between this and other phases. The change in the effluent colour has already been
reported in other studies. As reported  in some of them, it  seems to be reasonable to
assume  that this has something to do with the point of alum addition.  It is consider-
ed that  a deflocculation caused  by  over-aeration after alum addition has a  signifi-
cant effect  on this because such  a phenomenon did not take place at all in  experi-
ments in which alum was dosed from the end point.
     Table  1.7 is a comparison of the composition of condensed these substances
and that of solids in effluent from the control bay.
     In  the control  bay,  substances of obviously different quality compared with
activated sludge  flows out, but in the alum bay, activated sludge including alumi-
num itself comes out in broken-up form.
                                     232

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                           Table 1.7  Component of Solids

VSS/TS (%)
TKN/TS (%)
T-P/TS (%)
A2/TS (%)
SS in Eff.
(Control)
49.2
3.79
0.61
0
Return Sludge
(Control)
70.0
7.28
2.95
1.74
SS in Eff.
(Alum)
40.8
6.75
2.96
7.65
Return Sludge
(Alum)
63.0
5.85
3.14
8.10
1.3.6   EFFECTS  ON MICROORGANISMS
    The effects alum have on activated sludge protozoa have been discussed from
many angles.
    In this project, survey was conducted from two points. One is the microscoptic
examination of activated sludge protozoa. The other is the measurement of dehydro-
genizing activity, which is considered to have relationships with the metabolic activi-
ty of micro-organisms.
    Fig. 1.9  is the  comparison  between the two  bays of the dehydrogenizing
activity of activated sludge when 8 mg/C of aluminum was added. It shows hourly
changes at different points in the  aeration tank. Dt on the figure shows total activi-
ty. De shows  activity after substrates are washed  out (that of eudonegous respira-
tion)  On the control side, Dt is always higher than De, while De is  higher on the
alum dose side. In other words, activity rises after substrates are washed out. There
is  little difference in the De  value between the two bays.  This indicates that the
addition of 8 mg/£ of aluminum  is interferring biological  activities in  one way or
the other.  Similar phenomena are often observed  in sewage treatment plants where
relatively large volumes of industrial waste flow in.

                     Fig. 1.9 Comparison of Dehydrogenaze Activity
                                                         (Al 8 mg/8)
                                           o Inlet  (Alum) • Inlet  (Control)
                                           o % point (Alum) •% point (Control)
                                           A Vi point (Alum) A ^ point (Control)
                                           D Outlet (Alum) • Outlet (Control)
                                  12         14
                                     Time (hr)
                                      233

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     As for changes in protozoa, the numbers of spieces and population proved to
decline  in the alum bay comparing to the control bay when the concentration of
added aluminum  was high.  Fig. 1.10 shows monthly changes in the population of
total ciliata and activated sludge  ciliata per unit of MLSS in both  bays. Although
alum  addition  reduces the population,  the dgree differs with the  dose rate  of
aluminum.  There  is little difference between the two bays when aluminum is below
4 mg/£ (below 50 mg/C as alum).  Thus, it seems to be possible to assume that there
is little practical effect on protozoa when added alum is below 50 mg/£. As mention-
ed earlier, this dose rate is also effective for phosphorus removal.


                Fig. 1.10 Comparison of Ciliata Number in Activated Sludge
                                               Activated sludge cilita
                               Total cilita
                                           Control
  00
 Is
   p.
    "
T

                      1975
                                                      1976
                                            H	h-
         May  June  July  Aug.  Sep.  Oct.  Nov. Dec.  Jan.  Feb.  Mar.  Apr.  May  June (Month)
            Alum dose  AS   8 mg/8
                                 6mg/C
Smg/C
     Alum addition would considerably reduce  the population  of swimming type
ciliata (difference between total ciliata and activated sludge ciliata). But it is not yet
clear -  whether the reduction is a direct effect of aluminum or  it is a result of the
change in environment by  advanced removal of organic substances.
1.3.7  MATERIAL BALANCE OF  SLUDGE PRODUCTION
     It is known that  an increase in sludge production is a one of the most trouble-
some problems  in the  process. In this plant, continuous monitoring of primary
sludge and waste activated sludge is being conducted in both control  and alum bays
to determine  the  material  balance  of sludge  production.  Sludge  production  is
measured  by electro-magnetic flow meters and solids by ultra-sonic  sludge density
meters.
                                      234

-------
    The increase in sludge production by alum addition is theoretically calculat-
ed by the amount of AlPOa produced by the coagulation and Al (OKQa  by hy-
drolysis. There is also the transfer of organic sludge as in the control bay.
    Table 1.8 is the summary of daily influent loadings and primary sludge in daily
average monitored by each phase during the whole experimental period. Shown on
the Table is the material balances of sludge production of added aluminum of 8, 6,
4, 3 mgAl/C.
                     Table 1.8 Comparison of Sludge Production
"^ 	 ____Phas
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1.4  COSTS OF CHEMICALS
     According to the purchase prices in Nagoya City, alum is 21 ¥/kg in terms of
14.5%  AHOs  (¥273 per kilogram of aluminum).  The chemical cost required is
2.19¥/m3, 1.64¥/m3 and  1.09¥/m3  respectively when the rate of added alum is
100 mg/C, 75 mg/C and 50 mg/C.
     Sodium  hydroxide  is ¥61.3 in terms of one kilogram of NaOH,  which means
1.23¥/m3, 2.45¥/m3 and  4.9¥/m3  respectively when the alkalinity addition is
25, 50  and 100 mg/C (as CaCO3).
     Aluminum consumed in Japan is almost entirely imported from abroad. There-
fore, the cost is rather high compared  with other countries and its unit price is un-
stable.  These are the factors that should be taken into account in using aluminum
salts as coagulants. The situation is generally the same for iron salts. Therefore, it is
strongly considered  necessary to recover the used eoagulants from sludges and the
projects is now underway at the laboratory experiments.
1.5  SUMMARY
     The following  has  been obtained through  a series of experiments in which
alum was added to the aeration tank treating typical domestic  sewage in Japan,
which is relatively weak strength.
1)   When phosphorus contained in the influent is below 3 ~ 4 mgT-P/£, an alum
addition of 50 mg/C reduces the residual phosphorus to less than 0.5 mg/C.
2)   The phosphorus removal capability of return sludge is sufficient enough to be
taken into account in controlling alum dose.
3)   It is possible to botain nitrified effluent while removing phosphorus. But in the
case of a sewage of low alkalinity like one in Japan, it is necessary to add alkalis.
4)   Adequate care  should be taken in determining  the method to dose alkalis to
the aerator.
5)   The alum  addition of 50 mg/C has little practical effect on activated sludge
protozoa.
6)   The increase in  sludge production varies  with the alum dose rate, and in this
particalr studie increase rate was about 60%.
                                    236

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    CHAPTER 2.  DEVELOPMENT OF THE DEEP AERATION TANK
2.1   Introduction	238
2.2   Overall Oxygen Transfer Coefficient vs. Power Consumption	 239
2.3   Variation Range of DO Concentration in Mixed Liquor Due to
     Influent BOD Change	240
2.4   Separation of Bio-Mass from Liquid in Final Clarifier  	241
2.5   Design and Operation of Full Scale Deep Aeration Tank in Tokyo  	244
  2.5.1   Design Parameter	244
  2.5.2   Distribution of Suspended Solids and Stream Velocities 	245
  2.5.3   Performance and Economical Feasibility	245
  2.5.4   Construction Costs	246
2.6   Comparison of Diffuser and Jet Aerator in Deep Aeration Tank	246
                                   237

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2.   DEVELOPMENT OF THE DEEP  AERATION TANK
2.1   INTRODUCTION
     Because of the high prices of land, and the opposition from local inhabitants, it
has become almost impossible to purchase  new  sites  for sewage treatment plants
within the large cities.  And it is proving to be just as difficult to extend facilities at
existing plants.  Despite this, however, an amount of wastewater and requirements
for high purification of wastewater are increasing all the time. The only alternatives
left are to go upwards, or go down under  the ground.  The deep aeration tank is
an example of this latter alternative.
     A main advantage of increasing  the  depth of aeration tanks is (1) greater tank
capacity within the limited space available.  Addition to this (2) higher MLSS con-
centrations attainable because of the larger saturated concentration value of dis-
solved oxygen in  mixed  liquors,  and (3) less variation range of dissolved oxygen
concentration are  expected.  (2)  and  (3)  are no more than theoretical predictions at
present.
     In both Japan and the USA, the standard effective depth of aeration tanks has
been 4.5 ~ 5.0 m.  The 1975 ASCE Manual No. 36 states that "Ordinary liquor depths
will not be  less than  10 feet nor more than 15  feet. The depth is governed in part by foundation
and construction costs, in part by the size of the tanks.",  while  Babbit  (1960) adds  that
"Practice and experience in the United States have led to the adoption of a depth of about 15 ft
as  representing an economical balance between structural cost and operating cost.  A greater
depth, to about 20 ft, would give greater efficiency of aeration, but the cost of the tank would be
increased, and the higher compression to  which the  air  would be subjected would increase the
operating cost. Tanks shallower than about 15 ft would decrease these items but the efficiency of
aeration would be uneconomically reduced and the land area required would be proportionally
increased. "  Since then, aeration tanks have always been  constructed with depths of 4
to 5 m.  It is not exactly clear what happen being associated with the deeper tanks.
     The  adoption of deeper aeration  tanks poses many questions:— (1) would
there be sufficient generation of the  micro-organisms active for sewage purification,
(2) would these micro-organisms settle  properly in the final clarifier, and (3) how
economical would the running costs  of such a deep  tank be, etc.  In order to answer
these and  other questions, a pilot plant  was set up in 1972, prior to construction of
any full scale plants. An outline of this pilot plant is shown in Fig. 2.1.
                                      238

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                      Fig. 2.1  Schematic Flow Sheet of Pilot Plant
      Compressor
                                 Spray
                                                     Measuring weir
      Influent
      channel
                                              Clarifier
                                             010.0 m x H 3.0m
                                             V = 237m3
                                                              Outfall
                              Deep aeration tank
                              ^04.0 m x H 18.0m
                              V = 226m3
2.2   OVERALL OXYGEN TRANSFER COEFFICIENT  VS. POWER
      CONSUMPTION
     The relationships between Ki^V and water depth, and Kj^V and  air flow rate
(based on data from the pilot plant) are shown in Figs. 2.2 and 2.3 respectively.
            Fig. 2.2  Depth vs. KLa
  2,000

  1,000


,-,  500
.c
"e
>  200
03

   100


    50
                6 8 10    20
                  H  (m)
                                              Fig. 2.3 Air Rate vs. KLa-V
                                         2,000  -                  B
                                             1,000
                                               500
                                               200
                                               100
                                                50
                                                   40  60 80 100
                                                         Gs(Nm3/hr.)
                                                                   200  300
                                      239

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     Water depth and air flow rate are mathematically related to Ku by the follow-
ing expression,
         KLaV = K"'Gs(1-m)H(1-n)	(1)
     From the data, equation (1) is changed to equation (2).
         KLaV = 0.085 GsL38H°-72  	(2)
     It is  clear that  the overall oxygen transfer coefficient will be proportional to
water depth raised to the 0.72 power.
     The amount of power required  for air diffusion is given by the  following
expression: —
         L = K-H°-67	(3)
     A comparison  of expressions (2)  and (3) above will show that the increase in
power requirements due to the deep air diffusion,  is more or less offset by the
increase in oxygen transfer efficiency;  That is, there is little loss of economy caused
by the lower diffuser location.
2.3   VARIATION RANGE OF  DO CONCENTRATION IN MIXED LIQUOR
      DUE TO INFLUENT BOD  CHANGE
     Changes in the influent BOD concentration will result in changes of the oxygen
uptake rate (that is, dissolved oxygen concentration) in the mixed liquor. Variation
in mixed liquor dissolved oxygen concentration, Ac, is related to the oxygen uptake
rate, AyT by the following expression: —
               K
                                                                     (4)
                La
     And since the value of KLS is larger in deeper aeration tanks, Ac will be smaller
for a given Ayr. In other words, there should be smaller variations in dissolved
oxygen concentration for the deep tanks.  In Fig. 2.4, observed values of mixing
                            Fig. 2.4  DO in Mixed Liquor

                         15.0  r
                         10.0  -
                          5.0
                          1.0
                                 18m depth
                                                 Aye.
F/M
MLSS 1250mg/C
Air rate 380 ms/hr.
                                    B • 5m depth
                                                _Ave.
                                         F/M     103
                                         MLSS   700 ms/C
                                         Air rate  350 nr'/hr.
                              0  04  8  12 16 20 24
                                     Time
                                      240

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liquor dissolved  oxygen concentrations are plotted  for a 4 m,  and an 18 m  tank.
The amount of variation in the 18 m tank is clearly less (about half) than in the 4 m
tank, thus giving proof to the theoretical considerations.
2.4   SEPARATION  OF  BIO-MASS  FROM LIQUID  IN FINAL CLARIFIER
    Active bio  floe was pumped from an existing aeration tank to the  18 m pilot
aeration  tank.  At beginning the concentration of suspended solids in  the mixed
liquor was observed about 800 mg/C.  However, within 20 hours after commencing
operation, the MLSS in the pilot aeration tank had  fallen to 200 mg/C.
     The bio floe had been  carried out  with the effluent, since  it did not without
settle in the  final clarifier.  There was bio floe floating on the surface on the final
clarifier (see Fig. 2.6).
   800


  __ 600
 Is
 « 400

 S
   200
          Fig. 2.5 MLSS vs. Time
Fig. 2.6 Floated Sludge on the Surface
       of Final Clarifier
       0246  8  10 12 14  16 18 20 hr.
               Time after starting up
     This bio floe accumulated behind the scum baffle, and finally flowed over the
 weir. But once this problem is solved,  the  deep aereation tank  will be ready for
 practical use.
     Fig. 2.7 shows how a sample  of mixed  liquor, taken from the above pilot
 aeration tank, changed over a period of time. The bio floe did not float to the sur-
 face immediately after a sample of mixed liquor was poured to the  cylinder. Instead,
 the sludge particles agglomerated  together over a certain period of time, and once
 they reach several millimeters in size, they quickly rose to the top. This rising floe
 was found to have small air bubbles adhering to it (see Fig. 2.8).
      Fig. 2.7 Floating Sludge with Time
Fig. 2.8 Floe with Adhering Air Bubbles

-------
     A  special  analysis proved that the air bubbles  contented  a high nitrogen.
Nitrogen in the air which was diffused  into  the  mixed liquor at a depth of 18m
dissolved up to  saturating the liquor with nitrogen. But since the saturated nitrogen
concentration near the surface is lower, the excess dissolved nitrogen reverts to the
gaseous state, forming small bubbles of gas.
     Next, a sample of mixed  liquor was taken from  an aeration tank where the
diffuser was located at a depth of only 4 m. The floe behaviour was again examined
(see Fig. 2.9).
                     Fig. 2.9 Floe Behaviour (in 4 m Aeration Tank)
     In this case,  the  floe settled very well. This illustrated very clearly the close
relation between diffuser position and floe floating/settling behavious.
     In order to  purge the floe of the  adhering bubbles, re-aeration of the  mixed
liquor was tested.  All of the mixed liquor from the 18m aeration tank was flowed
through a series of four 4.5 m  re-aeration tanks, and re-aerated for 40 minutes (10
mins. in each tank). Samples were taken from each tank, and allowed to rest  for 30
min.  The degree of settling in each case has been shown in Fig. 2.11.
        Fig. 2.10 Reaeration

                     i    I
                   Fig. 2.11 Effects of Reaeration
       I inal tank,.	
     I inal clarificr
     10 0 m* x 30 mH
             2.0m
          Rcaerution tank
 2.0 in x 1.0 m xS.O m x4 = 40 m'
rif  ~
      — Air
      •"- Raw waste
      ~ Return sludge   *^ ~- ,
      GL + 0.8 m
                                          242

-------
    The results revealed that re-aeration for 20 minutes was sufficient to prevent
the floe from rising to the surface.  Table 2.1 listed the concentrations of dissolved
oxygen, nitrogen,  and carbon dioxide  in  the mixed liquors of each tank.  A com-
parison of this table with Fig. 2.10 indicated that the floe started to rise when the
nitrogen  concentration  exceeded 20 mg/B.  Special attention should be paid to the
fact that it  is possible  to  prevent floe from rising without reducing the dissolved
                    Table 2.1  Dissolved Gas Concentration Observed
Location
18m Depth
#1 Re-Aeration Tank
#2 Re-Aeration Tank
#3 Re-Aeration Tank
#4 Re-Aeration Tank
Standard Aeration Tank
02 (mg/fi)
12.7
12.0
8.8
9.4
8.3
8.2
7.8
8.6
8.7
9.3
3.2
N2 (mg/B)
27.9
26.4
22.3
22.1
20.4
19.8
19.0
18.8
18.9
19.3
18.3
C02 (mg/B)
30.1
31.6
-
16.0
-
27.7
-
23.2
-
21.0
44.4
nitrogen concentration as low as the saturation level (14.9 mg/B) under atmospheric
pressure.  This threshold  concentration of 20 mg/B corresponded to the saturated
concentration of dissolved nitrogen at a water depth of 5.8 m. The aeration depth,
5 m, which has traditionally been a standard has a meaning, although they do not
understand  significance of the meaning.  The 5 m are the depth in which bio floes
are free  from floating, since disolved nitrogen concentration in the depth is a bit
inside the threshold.
                                      243

-------
2.5   DESIGN AND OPERATION  OF  FULL SCALE DEEP AERATION TANK
      IN TOKYO
2.5.1  DESIGN PARAMETERS
     A deep aeration tank  has been installed at the Morigasaki Sewage Treatment
Plant in  Tokyo. Since this area is reclaimed foreshore, the ground is still not very
firm, making  it difficult to excavate beyond 10m.  Consequently, the effective
depth of this tank  is 10m.  And in order to prevent floatation of the bio floe, the
diffuser has been set half way down the tank. A cross-sectional diagram of the tank
is shown in Fig. 2.12.

                Fig. 2.12 Cross Section of Full Scale Deep Aeration Tank
    The baffle plate running down the center of the tank has been installed to assist
the mixing. The design criteria are as follows:
Influent flow rate:
Influent BOD:
Dimensions of aeration tank:
Number of aeration tanks:
Volume capacity:
Aeration time:
Air flow rate:
1,860,000m3/day
I50mg/e
8.4 m wide, 100 m long, 10 m deep 4 turns/tank
12
3 1,000m3/tank
4 hours
7.5 times of influent flow rate
                                    244

-------
2.5.2   DISTRIBUTION OF SUSPENDED SOLIDS AND STREAM VELOCITIES
       IN  THE  AERATION TANK
    Stream velocities actually measured in  aeration tanks where the diffused air
flow rates  were  5 and 7.5  times as much as the amount of influent are shown in
Fig. 2.13.
                     Fig. 13 Velocity of ML in Full Scale Tank
V
17
"^
\.
4.3
8
• *
8 (11.9)
14.5
(9.7) |
	 41.5 (27. 7J
4.3
6

""!
CO
p

-------
2.5.4  CONSTRUCTION COSTS
     The construction cost for unit  volume of the  10m deep aeration  tank is
approximately 1.4 times higher than a  5 m deep tank.
2.6   COMPARISON OF DIFFUSER AND JET AERATOR  IN DEEP
      AERATION  TANK
     In  recent years, the jet aerator developed in the states has also been available
in Japan.  It is well known  that although the running cost is high, it features a
greater oxygen transfer efficiency.  This means that it can transfer greater amounts
of oxygen without increasing the air flow rate.
     In  recent years, the jet aerator developed in the States has also been available
suddenly increased because of several reasons after the blower room and main air
pipes had been completed.  There was no available space left to extend facilities to
cope with the increased quantities, so the only alternatives were to deepen the
aeration tanks, and improve the oxygen transfer efficiency without increasing air
supply equipment.  The jet aerator seemed to answer the needs very well.
     The aeration tanks at this plant measure 10m deep, 10m wide, and 76 m long.
The jet aerator was installed at 5 m below  the surface.  Performance of the  system
were as follows.
Influent BOD:                llOmg/B
Effluent BOD:                lOmg/C
Detention time (for Q):         7 hrs.
F/M:                         0.3 kg BOD/kgSS/day
Air flow rate:                 0.37 kg BOD/m3
Power consumption:           2.9 times as much as influent rate

                                          kHW/kg BOD    kHW/m3 /inflow
                               Pump
                               Blower
                               Total
                                    246

-------
Fig. 3.14  Full Scale Deep Aeration Tank in Hiagari

-------
                                                           Fig. 3.15  Full Scale Deep Aeration Tank
00
                                                                                                       \MLPipe (For Future)
                                                                                                       Ail Pipe 600-2000

-------
 CHAPTER 3.  EXPERIMENTAL STUDIES ON PERFORMANCE OF RAPID
              SAND FILTRATION PROCESS FOR TERTIARY PURPOSE
3.1   Filtration Study at the Tokyo Full Scale Plants	250
  3.1.1  Coagulation-Sedimentation Filtration Experiment	250
  3.1.2  The Comparative Experiment of the Upflow Filter and the
        Downflow Filter	258
  3.1.3  Summary	296
3.2   Filtration Study at the Kyoto Pilot Plant	298
  3.2.1  Solid Removal by Filter Under Varying Flow  	299
  3.2.2  Solid and Organic Removal by Carbon Contractor	313
  3.2.3  Summary	321
                                 249

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3.    EXPERIMENTAL  STUDIES ON PERFORMANCE OF RAPID SAND
      FILTRATION PROCESS FOR TERTIARY PURPOSE
3.1   FILTRATION STUDY AT THE TOKYO  FULL SCALE  PLANTS
3.1.1   COAGULATION-SEDIMENTATION  FILTRATION EXPERIMENT
a.   Generality of the Tertiary Treatment Plant
    The department of Sewage Works of Tokyo Metropolitan Government and the
Ministry of Construction have jointly constructed the pilot plant of practical scale
for tertiary  treatment in Minamitama Sewage Treatment Plant of Tokyo.  The
construction started in August of 1974 and was accomplished in  March of 1976.
This plant comprises a sedimentation tank and two filter basins for the purpose of
removing suspended solids, BOD  and phosphorus from the secondary effluent of
sewage treated by the activated sludge method.
                             Fig. 3.1.1  Flow Diagram
                                                                   Signs
Re
F
L
X
A
C
1
0
®
a
IS

m
R
HeadLoss
Flow
Level
OpenDegra
Alarm
Control
Indicator
Calculation
Signal
Transmitter
Magnetic
FlowMeter
Calculator
Resistant
Current
Converter
Electro
-Electric
Positioner
Recorder
     Automatic Meter
       (Influent)
                 Automatic Meter
                 (Coagulation-Sedimentation
                 Water)
                                                      ~~toNo.2 FilterBasin
                                              Tr: Turbidity Meter
                                              Tn  Temperature Meter
( Effluent)
   PH Meier
   Electric Conductiv
   -ityMeter
Al  Alkalinity Meter
Do  DissolvedOxygen Meier
Cl : Residual Chlorine Meter
                                                                  Discharge
                                                                  Channel
                                    250

-------
     Concerning the treatment capacity of the plant, the coagulation-sedimentation
 capacity is 8,800 m3/day (2.32 MGD) and the filtration capacity is 17,600 m3/day
 (4.65 MGD).
     This plant is constructed so  that the flow may be divided into two for the
 experimental purpose as shown in Fig. 3.1.1; one of the flows is that of filtration to
 directly  filter the secondary effluent of sewage and another is that of coagulation-
 sedimentation filtration to filter the secondary effluent of sewage after its coagula-
 tion and sedimentation.  The coagulation-sedimentation tank is  the type of sludge
 circulation, which is the rectangular tank with the surface area of 225 m3  (2,421 SF)
 and a side of 15 m (49.2 FT) made from the reinforced concrete.
     The upflow speed of the effluent of sewage is 29.3 mm/min. (1.15 inches/min.)
 based  on the average treatment capacity (8,800 m3/day) and the average staying
 time in this tank is 22.36 h. based on the average treatment capacity. The rotation
 speed of the impeller is 2.65 r.p.m., that of the  scraper 3.9 r.p.h. and the width of
 the impeller band 50 mm (2 inches). The surface area of each filter basin is 57.8 m2
 (622  SF) its depth is 8.40 m (27.6  FT), the thickness of the filter layer is 1.20 m
 (4 FT) and the excess height is 5.90 m (19 FT).  This is non-constant-pressure filter
 basin whose water level rises as the head loss increases.
     Influent into the filter basin can be controlled constantly with the distribution
 tank.  The design  filter  speed is 152.2 m/day (2.59 GPM/SF).  The structure of the
 filter layer is shown in Table 3.1.1.  The waste water produced by the cleaning of
 the filter basin shall be  stored once in the cleaning wastewater tank and then sent to
 the primary  sedimentation tank of the sewage treatment  plant. The treatment
 capacity of this plant is below that of the tertiary treatment so that it is made a rule
 to perform the tertiary treatment of all the secondary effluent of sewage.

                        Table 3.1.1  Structure of Filter Media
Filter
Medio
Sand
Anthracite
Supporting
Grave 1
NO. of FilterBasIn
NO. 1 Filter Bosln
N0.2 Filler Basin
N03 Filter Basin
NQ2 Filter Bosln
NO.I.N0.2 Common
-,
',

Thickness
of Layer
(jnmllinch)
625(24.6)
625(24,6)
375(14.6)
375(14.8)
50(2.0)
50(20)
50(2.0)
50(20)
Effective
Size (mm)
0.61
0.7 1
1.35
1.52
2.00-3.36
336-673
6.73- 1 2. 7
127-19. 1
Uniformity
Coefficient
1.39
1 39
1 39
1 38
	
	
	
—
b.   Generality of the Secondary Treatment Plant
     This sewage treatment plant has only Tama-Newtown (the number of families
13,571 and the population 46,160 as of 1976, Nov. 1) as its drainage district and it
collects sewage through the sewer of separate system so  that its maximum sewage
amount per hour is almost six times of its  minimum sewage amount per hour as
shown in Fig. 3.1.2.  Accordingly, the  maximum sewage amount per hour is  1.58
times of the average sewage amount of a day and the minimum sewage amount per
                                     251

-------
hour is 0.27 times of the average sewage amount of a day.
     The peak time of the entering sewage amount is 10:00 a.m. and 10:00 p.m.,
and  the  entering sewage amount becomes extremely low  at 6:00  a.m.  For this
reason this sewage treatment plant is difficult to control the operation.

                    Fig. 3.1.2 Hourly Variation of Influent Amount
                      eoo

                      600

                      I4OO

                     3200

                     X
                     Ceoo

                     ;soo

                     £430

                      200
August 25-26,1976
                          10  12  14  16  IS  20 22  24 2  4  6
                                       Time (Hour)
     The  operating condition of the secondary sewage treatment facility  in this
plant is indicated in Table 3.1.2.  The hourly variation of the quality of the secon-
dary effluent of this plant compared to the raw sewage is as shown in Fig. 3.1.3 ~
3.1.5.  The concentration of suspended solids (SS) in the raw sewage attains to the
peak both at 10:00 a.m. and 10:00 p.m. and this coincides with the peak hour  of
the entering sewage amount.  At the peak time of 10:00 a.m., the SS concentration
of the raw sewage was almost 425 mg/£ (3.8 times of the average SS concentration
of the raw sewage) and it was found that this concentration  was quite larger than
that of almost  160mg/£  (1.4  times of  the average SS concentration of the raw
sewage) at the  peak hour of 10:00  p.m.  The SS concentration of the secondary
effluent became the highest; almost five times of the average SS concentration  of
the effluent, influenced by the peak of the entering amount.  The total phosphorus
(T-P) concentration of the raw sewage attained to the peak at  10:00 a.m. and it was
almost 2.7 times of the average T-P concentration.  The T-P concentration of the
secondary effluent was averaged by  the secondary treatment and was constant with
almost no hourly variation.
     The ammonia nitrogen concentration  in the raw sewage attained to the peak
also at 10:00 a.m. (2.3 times of the average concentration) and there was almost no
variation of the effluent found.  These continuous water quality tests during 24
hours were taken  place 3  times in August.  The load quantity, the loading average
concentration  and the  removal rate concerning every  waste water quality were
determined based  on the wastewater quantities and the  concentrations obtained
during the hourly measurement, and  the average value of the three tests are shown in
Table 3.1.3.  The  wastewater load per person in  this sewage treatment district was
found  to  be 374 C (99  gallon)  and  BOD load to be 68 g  (0.15 lb.), based on the
numerical value of 1976, Nov. 24 shown  in Table 3.1.1.  The other loads per person
are as shown in Table 3.1.4, being determined upon the Table 3.1.3.
                                     252

-------
Table 3.1.2  Operational Conditions of the Secon-
             dary Treatment Facilities of Minami-
             Tama Sewage Treatment Plant
1 Xeorand Dote
Effluent Quantity {m^doy)
Returned Sludge Ratio (%)


Average Detention Time
[Primary Sedimention)(riour)
Average DetentionTime
Secondary SedimenfionXnour)
Air Blow Rolio(Air Blow
Sludge Age (day)
( I^g/m3/doy )
BOD Lood(Kg/MLSS Kg/day)
Average BOD of Sewage
Flowing into AerationTank
»3 (mg/1)
Average SS of Sewage
Flowing into Aeration Tank
*3 (mg/ 1 )
MLSS *4 (mg/1)
MLVSS *4 (mg/1 )
MLVSS/ MLSS (%)
S V * 4 (%)
S V I
1975
5 14
9510
100


*I
49
45
79
12.8
022
0.16
143
7 1
14 19
994
70
22
152
827
I030C
94
73
6.0
43
6.4
253
0.17
0.09
98
42
1795
919
51
2 1
115
11.13
9.240
104
7.8
6.7
4.5
62
18 1
0 17
0.10
1 10
60
1649
1060
65
28
167
1976
2 17
9980
94
76
62
44
69
6.6
020
0.20
1 20
92
995
857
86
80
802
5 II
13,880
79
59
45
3.4
68
58
031
0.26
137
92
1205
938
78
38
312
8.12
14670
87
5.3
4.2
3.1
8.8
64
029
0 15
120
122
1892
1.157
61
28
146
11.24
17.250
86
4.8
«2
72
2.8
80
42
0.44
0.37
1 57
100
1187
899
76
26
215
Effluent
Quo] ily
PH
Tronspe
-roncy(cm)
CODxn
(mg/1)
SS(mg/l)
BOD(mg/l
Influent
Effluent
Influent
Effluent
Influent
Effluent
iufluent
Effluent
Inlluenf
Effluent
72
71
5
85
78
1 2
1 38
6
178
5
73
70
7
1 00
68
8
1 16
3
1 61
3
73
69
3.5
100
64
8
1 30
5
185
4
73
67
5.0
1 00
72
9
1 26
2
1 60
2
7 1
70
6
1 00
62
8
1 1 8
4
180
8
7 1
69
6.5
50
49
8
1 02
8
1 1 3
6
73
4
5
64
64
1 0
128
5
183
4
     * I Primary Sedimen
     *2
     *3 Composite sample
i Copocify-, 1950m3
        5180m 3 (I83,OOOCF)
        t he Aero lion fank,
    Table 3.1.3 Removal Ratio by Secondary
                 Treatment
\Section
Woter\
OuolityX
Hems X^
S S
T-P
N H« - N
Loading
InfluentLood
Capacity
Kg/day
(LBS/doy)
2,02 1
(4,456)
70
(154)
307
( S77)
Effluent Load
Capacity
Kg/day
(LBS/doy)
150
(331)
4 1
( 90)
1 7
(37)
Average Concentration
Influent
( mg/ll
1 52
5 3
233
Effluent
(mg/1)
II
2.7
1.3

Removal
( V.)
93
4 1
9 4
   Note; Meosur ing dotes ore l hree times of Aug. It -12, Aug. 18-19 and
       Auo.25-26  in (976.
       ; Removal con be calculated out from the load copoci! y
                               Fig. 3.1.3
                                 Hourly Variation of SS Concentration
                                 in Secondary Effluent

                                                    Fig. 3.1.4  Hourly Variation of T-P Concentra-
                                                               tion in the Secondary Effluent
                                                                   August 25 -26, I976
                                                         K) II 12 13 14 I5I6 17 18 « 2021222324 I 2345678 (Averoge)
                                                                        Time (Hour)
                                                  Fig. 3.1.5 Hourly Variation of NH+, -N Concen-
                                                             tration in the Secondary Effluent
August 25-26,1976
                                                                       Row Sewoge
                                                                       Se
                                                                                             -X26.5)
                                   O II 12 13 M 15 16 17 18 192021 222324 t  234567 BtAveroge)
                                                Time (Hour)
                                                        Table 3.1.4 Pollution Load Per Capita
Woter
Quality
tems^ ^.^
S S
T-P
N Hi - N


g/doy/ person (LBS/ day/100 persons)
4 4
1 5
6 7
(097)
'(033)
(148)
                                               253

-------
c.    The Experimental Result of the Tertiary Treatment
     The experiment  of the  tertiary  treatment  was conducted,  using alum  (Al,
(SO4)3- 18H2O) as the coagulant.  The alum was added automatically in proportion
to the3 influent amount and the added amount during each experimental period is as
shown in Table 3.1.5. The experimental result of the tertiary treatment is indicated
in Table 3.1.6. When alum was added below 40 mg/C, the formation of floes was
insufficient and subsequently the formation of sludge blanket in the coagulation-
sedimentation tank becomes insufficient. Particularly when the dosage was 30 mg/8,
no blanket was observed. In the case of 30 ~ 40 mg/B  of alum dosage the SS re-
moval was higher in the directly  filtered effluent  than in the coagulation filtered
effluent as shown in Fig. 3.1.6. As for the coagulation-sedimented wastewater, the
average removal was extremely low; below 25%.  This was caused by carry-over  of
the floe  formed in  the  coagulation-sedimentation  tank.  The BOD removal in this
case was  not greatly different  with  coagulation-sedimentation filtration and  with
direct filtration; it  was  around 75% as shown in Fig. 3.1.7.  The coagulation-sedi-
mented wastewater, however, as the floes caused  carry-over and intermixed into the
effluent, had very low BOD removal.  The T-P removal in this case was around 60%
as shown in Fig. 3.1.8 in the coagulation filtered water indicating incomplete coagu-
lation reaction and  moreover around 45% in the  coagulation-sedimented water due
to carry-over, both  being low removal.  But it was largely different  from the removal
of 7% of the direct filtration and this proved the reaction effect  of the coagulant.
When raising the  dosage to 50 ~ 60 mg/C, the coagulation reaction was almost  com-
pletely performed and the produced  floes formed the blanket zone in the coagu-
lation-sedimentation  tank. For this reason,  the T-P removal of the coagulation-
sedimentation filtered water attained  to the  peak of 95%.  Also concerning the
coagulation-sedimented  wastewater, T-P removal  was 90% at the dosage of 60 mg/C,
not so less than the coagulation-sedimentation filtered effluent.  But concerning SS,
as indicated  in  Fig. 3.1.6, the removal of the  coagulation-sedimentation filtered
effluent was  only 5% above that of the direct filtered effluent.  The removal of the
coagulation-sedimented  effluent was also not more than 50% and it  showed that
outflow of fine floes was inevitable due to the inflow fluctuation. Also as to the
 BOD, the difference of the  BOD removal  between the coagulation-sedimentation
 filtration and the direct filtration was 5%; degree of the coagulation effect being
slightly acknowledged.
                             Table 3.1.5  Alum Dosage
Experiment
Number
I
II
!l[
IV
E x pe rime nt Per lOd
From Sep.20foOcl 14I976
FromOcl 16 lo Nov 18.1976
From Dec.
20,1976 to Jon,IO,l977
"com Dec3ioDecl8 1976
Design Alum
Doso ge
(in the effluent )
60 mg/1
50
40
30
Averoge Alum
Dosoge
(Al/P MolRotio)
2 1
I 6
I 1
0-9
                                      254

-------
  Table 3.1.6  Experiment Results
Table 3.1.6  Continued

Item



T-P
AI/P
Ex perlment Period
Alum Dosoge
D i v i siorT^~--- __^
Total
Desd
Coagulation
-Sedimentation



-Sedimentation
Filtration

-sZin
DirectFillraton
Coo,ulor,=n
Filtroton
Ratio to Total
Ratioto Soluble
Concen
•trotion
Concen
-tration
%
Concen
-tration
Removal
Concen
-tration
Removal


Removal

Concen
•tration
Removal
Concen
-tration
Removal
Concen
•trotion
Removal
T-P
T-P
1
60ppm
N
20


Zo
20
2O
20


2O

16
16
16
16
16
16
MX
7.6


5.2
41
6P
51


53

O
57
92
3
4O
31
0
36
98
Mi
54


3£
27
35
13


66
21
O
16
78
!
99
4.0
O
35
94
Av
6£


45
33
49
23


40

0
37
66
2.6
79
0
12
96
1.995
2 46
II
SOppm
N
26
25

28
26
28
28


26

20
20
20
20
20
20
Mi
16
3
B.S
87
ze
67
8 1
63


7,

22
78
3
94
27
9
99
89
Mi
6,6
3,4
4O
4.
ie
44
20


30

0
61
39
2
46
10
0
30
71
Av
92
7.1
77
6.0
33
63
30
52
43

02
69
2
99
8
61
81
1.428
I.S57
III
40ppm
N
12
12

2
12
12
12
12
IZ
12
12
12
12
12
12
12
MX
17
5
15
6
89
16
9
28
19
9
36
13
8
41

2
27
56
3
49
II
56
75
Mi
90
6JB
67
6.6
3.4
64
O
55
9

36
35
2
87
6
O
77
56
Av
"3.
5
0
8
79
II
4
6
II
22
93
32

I
97
45
3
26
8
I
38
62
1043
1 135
IV
30ppm
N
4
12

14
14
14
,4
14
14
14
14
14
14
14
14
14
MX
a
7
14
e
93
14
3
2E
12
6
34
4
46

2
41
66
3
60
IO
86
74
Ml Av
«•'!•
8.612
7860
«'i
13 18
78 99
2027
61 89
26 54

cU
3040
78 13
0 6
7946
48 56
0.641
0.892
Fig. 3.1.6 Comparison of SS Removal
            Coogulaton-Sedimentotioi
        30         4O         5O
             Alum  Dosoge  { mg / l )

Item






rurbidil)
BOD
Ex periment Period
Alum Injec tlon Rate
Division -^-~~^^
Row Water
Coagulafi
-Sedlmen
Direct Flit
Coagulati
•Sediment
Filtratio
on



on

Raw Water
Coagulat
-Sedimen
DirectFilf
Coagulot
-Sedlmen
FJltra f o
Row Water




on
1
Total
Disso-
lved
Coagulation
-Sedlmented
Direct
Filtration
Coagulation
-Sedimentation
Filtration
Concen
-Irotton
Concen
-f ration
Removal
Concen
-trallon
Removal
Concen
•t ration
Removal
Concen
-tratlon
trotion
Removal
Concen
-trotion
Removal
Concen
-trotion
Removal
-i ration
Concen
-tration
%
Concen
-tration
Removal
Concen
-(ration
Removal
Concen
trotion
Remcwl
1
60ppm
N
e
6
e
6
6
6
6
I
II
i
II
II
1
M
3
3

5
3
3
3
9
S
MX
6,2
10
97
LO
98
Bt
KX
58
09
94
0.8
96
O
14
KX
3.9
L9
47
ZB


2.
94
is
93
Mi
Z.I
02
0
01
71
0
rt
33
04
82
O2
65
0
96
3.0
0.6
IS
0
02


03
64
P.2
7B
Av
Of
3Q
49
05
91
02
93
30
O£
67
Q5
9O
0
06
93
43
13
31
09


oe
63
05
69
II
90'ppm
N
2fi
26
26
28
28
28
28
28
26
28
28
28
28
ze
10
10

10


10
10
10
10
Mi
34
4
62
85
Q8
99
03
DO
24
2
33
96
IO
98
04
OC
16
0
19
23
3.2


16
91
17
94
Mi
34
17
0
a i
83
0
95
25
OS
42
0.2
82
0
93
4.3
0.6
9
Oft


0.3
73
0.3
79
AV
89
32
32
04
94
02
98
63
II
76
CL6
90
01
96
93
,4
17
26


13
64
1.0
60
III
40ppm
N
12
12
12
12
12
12
12
12
12
IZ
12
12
12
12
4
4

4


4
4
4
4
MX
16
3
14
8
54
41
94
M
87
II
26
1
77
31
3
89
22
8
96
14
9
32
22
70


34
07
8.6
86
Ml
70
3.7
0
Qfi
69
.
59
78
2,6
39
2
67
03
76
10
6
1.3
14
36


17
44
1,6
42
Av
Z
6
9.4
23
2.0
84
23
79
24
6
ra
58
6,2
eo
42
as
12
e
24
19
55


3S
75
3£
74-
IV
30pprn
N
14
14
14
14
14
14
14
14
14
14
14
14
14
14
4
4

4


«
4
4
4
Mi
14
0
13
6
70
2.6
95
4.1
93
14
1
44
96
3.3
97
1.6
99
a*
71
48
8.2


95
B9
43
91
Mi AV
4.0 94
2.1 8.C
0 17
0412
seas
O.I 1.9
4273
4.S69
0223
3967
0.3 14
5t eo
2,°*
76 69
-X
1332
12 27
GO 73
IO 36
1,4 36
36 70
1.1 23
70 79
                                                           removal      -,
                                                    f * N  ;  Number of Samples
                                                       MX j  Maximum
                                                       Ml ;  Minimum
                                                       Av ',  Average
                                           255

-------
   Fig. 3.1.7 Comparison of BOD Removal
Fig. 3.1.8 Comparison of T-P Removal
                                          f°
                                          E
     The BOD removal, however, became high in the coagulation-sedimentation and
as high as in the direct filtration.  We consider from  this fact that the outflow of
fine floes does not greatly influence the BOD removal.
     The data of Table 3.1.1 are obtained from  the  daily grab samples of 10:00
every morning.  In  order to investigate the hourly variation of the  water quality
during continuous 24 hours as for the secondary  effluent, the direct filtered efflu-
ent,  and the  coagulation-sedimentation filtered  effluent  is shown in Fig. 3.1.9
through 3.1.12.  The measurement period was from Oct.  13 to Oct.  14, 1976, which
were the final dates of the experiment I (the alum dosage; 60 mg/C, the average mol
ratio of Al/P; 2:1).  Fig. 3.1.9 shows that rapid hourly variation of T-P in the secon-
dary sedimented effluent between 3 ~ 4 mg/C. But in the direct filtered effluent,
soluble T-P had not so wide variation  between 2.7-3.3 mg/C. This was due to the
fact  it was not influenced by  the  floes outflown from  the secondary sedimented
effluent.  The addition of alum this day (Al/P mol ratio) is 1.88 on the average, 2.08
in maximum and 1.68 in minimum. This is lower than  the average alum mol ratio of
2.1 in the experiment I. Therefore the average T-P concentration in the coagulation-
sedimentation filtered  effluent of this day was 0.28 mg/C; higher than the average
T-P concentration in the coagulation-sedimentation filtered effluent in the experi-
ment I of 0.12 mg/C.  But, as the coagulation tank being the type of sludge circula-
tion, when  the Al/P ratio varied hourly or in its purposes due to the variation of the
T-P concentration in the raw wastewater (secondary  effluent), the T-P concentra-
tion  in the  coagulation-sedimentation  filtered  effluent was not influenced.  In other
                                     256

-------
words, when the addition of the coagulant in  coagulation-sedimentation treatment
was conducted not by the Al/P ratio control but by the flow rate control, we could
obtain quite stable phosphorus removal.
  Fig. 3.1.9  Hourly Variation of Total Phos-
            phorus Concentration
                        Ocl. 13- I4,I976
A]/ P Mol Rot io
Not e '. Alum Injection quant Ity isSOpprn io water
    mount.Thecompared phosphorus concentrator
    ion soluble total phosphorusOoia] phosphorus
    fdireci Filtration).   4	  -^1.88)
    10 II 1213 14 15 1617 18 19 202122 ^4  2  4  6  8 (Average J
                                      Fig. 3.1.10 Hourly Variation of SS
                                                 Concentration

                                                     Oct. I3-I4, I976
                                                              >	o- Row Worer (Secondory Effluenf)
                                                              t	•*- D I reel Filtrorion
                                                              '	*- Coogula tion-Sedlme tot Ion Filirofion
                                                                                  -•-(0.45)
                                                                             ^
                                       IO   12  14  16  IS  2O 22  24  2  4
                                                     Time ( Hour)
  Fig. 3.1.11  Hourly Variation of Turbidity
                                     Fig. 3.1.12 Hourly Variation of CODMn
                                                Concentration
                      Oct.l3-I4.l976
           -•	••— Direct Filtration
                                '""" -4-(0.44>

                                	• +<0 14 ) '
    OH I2I3 I46 I6I7I8 f92O2!22 24 2  4  6  8  IO (Average J
                                                                OCT. IO- I4, I976
                                                           Row Water ( Secondory Filirofion)  *<4I6)
                                                           Df reel Ftlf rorion
                                                           Coagu lation-Sedimeniot Ion FiTtrat ion
                                                   tO II 12 13 14 15 1617 18 19202122  24  2  4  6  QtAverogeJ
                                                                  Time ( Hour )
      Fig. 3.1.10,  3.1.11 and 3.1.12 show that concerning SS, turbidity and CODMn
 the coagulation-sedimentation  filtered  effluent had a  little  more excellent water
 quality than the direct filtered water.
      We can get the following summary from the above described;
 (1)  When dosage of alum is maintained more  than 50 mg/C (Al/P mol ratio; 1.6 ~
 2.1), the coagulation reaction would be complete.
 (2)  Concerning  BOD  and  SS removal  rate;  there will be no significant  difference
 between  the  direct  filtration  and  the coagulation-sedimentation  filtration:   the
 removals of  70 ~ 85% and  85 ~  95% respectively were obtained.  However, at the
 dosage of more than 50 mg/2,  the removal of the coagulation-sedimentation filtra-
 tion is  5% more than that of the direct filtration.
                                          257

-------
(3)  Concerning the  removal of  the  phosphorus; the coagulation-sedimentation
filtration can provide  the removal of around 55% at the alum dosage of 30 mg/£ and
that of high as 95% at  the dosage of 60 mg/C.
(4)  Only by coagulation and sedimentation, the stable water quality is difficult to
be obtained.  Especially at the low dosage of alum the removal of BOD  and SS was
not improved due to  carry-over of floes.  Even at  the high dosage,  the  SS removal
rate was not more than 50% because of the outflow of fine  floes and the removal
of phosphorus was also 5 ~ 15% less than that  of  the  coagulation-sedimentatio
filtered  effluent.  But at the high dosage of alum,  the BOD removal nearly as high
as that of the direct filtration will be obtained.
(5)  When the addition of alum was conducted by the flow ratio control, the con-
siderably stable removal of phosphorus was obtained.
3.1.2  THE  COMPARATIVE EXPERIMENT OF THE  UPFLOW  FILTER  AND
       THE  DOWN FLOW  FILTER
a.   Generality of the Facilities
     With the purpose of comparing the upflow filter and downflow filter, the filter
basins were constructed in Morigasaki West Sewage Treatment Plant of Tokyo and
the experiment was performed.  Its filtration capacity is 24,000 m3/day (6.3 MGD).
The  constructed filter basins are two upflow  filter basins and two tri-media filter
basins as downflow filter.  The  construction  was completed  in March,  1974. The
flow of the  experimental facilities is so that the secondary  effluent may be sent
simultaneously to the  upflow filter basin and to the tri-media filter basin as shown
in Fig. 3.1.13.  The surface area of both  filter basins  is 30m2  (323 SF) and the
structures of each filter basins  are shown in  Fig. 3.1.14 and Fig. 3.1.15 respec-
tively  The compositions of filter media of each filter  basin are indicated in Table
3.1.7 and in Table 3.1.8. The design filter rate is 200 m/day (3.41  GPM/SF) in both
filters.

              Fig. 3.1.13 Flow Diagram of the Upflow and Tri-Media Filters
             6 So.
             7 Air
                                                 Tri-Medio Filler

                                                 I. Influent volve
                                                 2 Flllrote valve
                                                 3. Drainage valve
                                                 4 Bochvatfi water valve
                                                 5 Surface-wash water vol
                                                          Discharge
                                                           ro Tokjo Bay
                                     258

-------
    Fig. 3.1.14 Cross Section of the
             Upflow Filter
     Fig. 3.1.15 Cross Section of
               Tri-Media Filter
  Table 3.1.7 Filter Media Characterization
           of the Upflow Filter

Filter
Medium
Support
media
Total
Depth
Nome
Sand
Gravel
Gravel
Gravel
Specific
Gravity
2 63
265
2 65
2 65

Depth
( m )
I, 700
250
250
I 50
2, 350
Particle Size
0-8 ~ 2 0
20 ~ 3 0
8 0 ~ 12 0
40 0 ~50 0
Effective
, size
(m m I
I 2
	
	
—
Uniformity
Coefficient
I. 27
—
—
	

Table 3.1.8 Filter Media Characterization
          of the Tri-Media Filter

Filler
Media
Total
Depth
Support
Media
Total
Oepl h
Name
Anthracite
Silica
Sand
Garnet
Specific
Gravity
I 39
2 62
4 05

Garnet
Grave I
Gravel

405
2 65
2 65
265

Depth
420
230
I I 0
760
75
60
60
60
I .0! 5
Rjrricle Size
0 84 ~ 2 0
0 42 ~ 084
0 18 - 0 42
iffecijve
I mWf
I 22
0 42
0 29
Uniformity
Coefficient
I 4 I
I 46
I 53

I 5 ~ 3 5
5 0 - 10 0
I 0 0 ~ 20 0
20 0 ~ 30 0
2 0
—
—
—
I 80
—
—
—

b.   Experimental Results
(1)   Water quality test results
     From the middle of August through September of 1974 (summer season), the
both filters were operated at various filter rates; 100 m/day (1.7 GPM/SF), 200 m/
day (3.4 GPM/SF), 300 m/day (5.1  GPM/SF), 400 m/day (6.8 GPM/SF) and 500
m/day (8.5 GPM/SF)  and a  test at one filter rate was continued for 3 weeks. From
November 14 to December 26 of 1974 (winter season), the filters were operated at
the constant filter rate of 300 m/day (5.1 GPM/SF).  Sampling time was 10:00 a.m.
every morning.  The average values obtained from the chemical analysis of samples
of this test are listed in Table 3.1.9. Numbers of samples were 4 ~ 6 for each  of
a given filter rate in summer season and about 14 in winter season. In addition  to
the measurement  of  the above quality characteristics,  hourly variations  of BOD,
COD and SS were  observed as shown in Fig. 3.1.16 through 3.1.20.  From these
analyses, the following results were obtained:
                                     259

-------
Fig. 3.1.16  Water Qualities with Time
             (Filter Rate 100 m/d)
                   Fig. 3.1.17-1  Water Qualities with Time
                                  (Filter Rate 200 m/d)
                            -Tri-M
                            -Tri-M
 SS
 CO Dun
 BOO
a SS
0 CODun
a BOD
--O--O--  Influent SS
--•"•--  InfluentCODui
—o-tr-  Tri-MedioSS
 • •   Tri-MedioCODMn!
                                                                                    A
                                                                                   /  \
               T ime  I fir;
                          Fig. 3.1.17-2 Water Qualities with Time
                                        (Filter Rate 200 m/d)
                           --0--0-- Influent  SS
                           --•-*--   ••   CODMi
                           --O--0--      BOD
           ^
                                            21   23   I   3   5   7   9
                                                                                       Upflow SS
                                                                                       Upftan CODMn
                                           260

-------
Fig. 3.1.18 Water Qualities with Time
             (Filter Rate 300 m/d)
Fig. 3.1.19 Water Qualities with Time
             (Filter Rate 400 m/d)
   Filter  Rote  300 m/doy
          I'  IS il   23   I    3   5  7   9   M
                                                             Filter  Rote  (400m/ doy)
                           --o-o- Influent  SS
                           '-•--*-- Influent CODMn
                           —o-o— Tri-Med.o SS
                             • »   Tn-MedioCODun
                                                                                       A
                                                                                            Upflow  SS
                                                                                            Upf lowCODMn
                                                                           22      1
                                                                         Time  ( hr )
                       Fig. 3.1.20 Water Qualities with Time (500 m/d)
                              _H><^. Inf SS         I
                              --•--•-- Inf CODMn       I
                              --©-«-- Inf BOD        |
                              —o-o— Tri-Medio SS     |
                               * *    "     CODMrt
                              -©-0-  .,     BOD
                               Filter Rale  500 m/rjoy
                                                          -o—o— Upf'ow S3
                                                           • «  UpflowCODur
                                                          -0-0- Jpllow BOD
                                               261

-------
                       Table 3.1.9 Water Quality Characteristics
^Filter
v5<
ss
COD
Cr
COD
Mn
BOD
T-N
K-N
NH3
-N
N02
-N
N03
-N
DO
UBS
PH
T-P
Infbent
Effluent
Removal
InfLent
Effluent
Removal
Influent
Effluent
Removal
Influent
Effluent
Removal
Influent
Effluent
Removal
Influent
Effluent
Removal
Influent
Effluent
Removal
Influent
Effluent
Increase
Influent
Affluent
Increase
Influent
Effluent
Decrease
Influent
Effluent
Removal
Influent
[ffluenl

nfluent
Effluent
Removal
m/d
I 00
Upfbw
9
0 7
92
Tri
-Media
I
0 7
92
21 I
IS 7
26
5
4.7
I 6
8
3 2
63
8
7 6
7 3
16 2
2 3
6
5 0
I I
6
3 3
62
2
7 8
4 9
5 6
4 7
I 6
5 0
I I
3 6
3 I
I 4
3 5
3
0. 09
0 48
530
2.9
272
- 7
S
2 6
49
0.52
580

26 I
- 10
I
0.9
83
0 I 6
0 17
-6.3
O.I 7
- 63
7 2
7 2

7 I






m/d
200
Upflow
6
0.6
9 I
Tri
-Media
9
0.4
94
2I.9
16 0
27
5
4.5
I 0
I 5. 9
27
0
4.3
I 4
7 I
2 3
68
4 4
38
7. 9
7 6
3 8
7. 8
I 3
5. 3
4 2
21
4 6
I 3
3 6
2.8
22
3 3
8
0 07
0.63
900
2.
2.82
8. 5
5
I. 3
75
0 36
51 0
0
2.8 I
8. 1
2
04
92
0 23
0.26
- I 3
0.27
- 7
7
7 I

7 I






m/d
300
Upflow
Tri
- Media
91 (97)
07 (09)
92 (9 I)
0.9(1 2)
90(88)
2I.I ( 31 7 )
16.5(19.5)
221 39)
16 5( 20 9
22 (34)
5. 6 (67)
51 ( 54)
9(19)
45 ( 5 7)
20 (15)
8.6 15.6)
2.5 (39)
71 (75)
1.9 ( 5.5)
781 65)
82 142)
7. 6(136)
73 (42)
8 1(13.3)
1 2(6 3)
5. 6 (13 2)
4-^ (12 1)
14(8)
5. 5( II 8)
5(11)
36 (96)
32(9 1 )
11(5)
3 8(8.5)
-6 I 12)
0 09 ( 0. 05 )
0. 54(0 I2)|o 14(0 31)
660(240)|I60(620)
291 (0.97)
2.63(1 45)
-96 (60)
5. 1
2.3 (6 0)
55 (1 6)
6.89(1.14)
-0.7(28)
(6. 1 )
36(25)
29(59)
0 16 (0.56)
016(0.19)1017(0.38)
0 (66) [- 6(32)
7 2
7 1

7 2

(473)
( 3. 9 5 )
(165)
(4 26 )
(99)
m/d
400
UP«°» I^MBiia
6.9
0 9
8 7
0.9
87
21 9
17 1
22
16.9
23
5 0
4 7
6
4. 4
1 2
7. 1
2. 8
6 1
2.8
6 1
7. 9
7 5
5. 1
7 5
5 1
5 3
4 2
2 1
4 2
2 1
3.6
2.5
3 1
3 0
1 8
0 07
0 62
890
2
2 73
50
5
0.8
85
Q53
760
60
2 79
6. 6
2
0 6
89
0 23
0.21
22
0.23
0
7 1
7 1

7 1






m/d
500
Upflow
-TWedia
7 3
0 9
88
08
87
23 5
1 73
26
16 9
28
5 7
4.2
26
4 1
28
1 6.9
3.6
79
4 4
74
8 6
8.8
7 4
8.8
7.4
7 0
6 0
1 4
6. 1
13
4 5
4.3
4.4
4 1
8. 9
0.09
0 28
200
2
2.45
2 5
5
1 3
74
0 08
-10
39
2.66
11.3
.0
2 0
60
0 37
0 37
0
7
72




0. 37
0
2
7 3




                            data except the removal
                           pressed by %
                                            is mg/1
1)   Regarding the effluent quality characteristics, there was no significant differ-
ence found between the effluents from the upflow filter and the tri-media filter.
2)   No difference of the effluent qualities from the both filters was caused by the
variation of the filter rate.
3)   The both filters could produce the stable effluent qualities against the influent
quality fluctuation.
4)   SS concentration  in  the effluents from the both filters averaged less than 1.0
mg/£  during  the summer season and less than  1.2mg/C  during the winter season
(average SS removal: 90% on the both systems).
5)   The effluent  BOD concentrations from the both filters averaged less than 4.4
rng/C  in the summer and less than 5.5 mg/C  in the winter (average BOD removal
ratio: 60 ~ 80%).
6)   Despite  of the significant BOD reduction, CODcr and CODMn removals were as
low as 20 ~ 25% and 10 ~ 20% respectively.
7)   Nitrogen removals were  1  ~ 7% in Total-nitrogen, 10 ~ 20% in both Kjeldahl-
nitrogen and Ammonia-nitrogen.
8)   Nitrification took place in the filters in some degrees.
9)   ABS removal could not be expected through the filter systems.
                                      262

-------
10) pH change was not observed through the sand filter system.
(2)  Cleaning of filter basins
    When filtrations  are continuously conducted, suspended solids in the raw water
are filtered and stored in the filter bed.  As the amount of suspended solids stored in
the filter bed increases, a filter head loss rises and finally reaches a terminal head loss
because the pore spaces of the filter media are clogged with the  suspended solids.
In such filter condition, it is difficult to obtain the designed filtration rate. Then,
it is required to perform an operation of washing the filter bed and cleaning the
suspended solids stored in it. This operation is so called backwash.
    The backwash program  for  both filters can  be carried out manually or auto-
matically.  The automatic filter  backwash is controlled  either by  time period  of
filtration, filter head loss and effluent turbidity. And also any patterns of backwash
procedure can be selected with a pinboard timer that has 6 variations and 30 steps.
A desirable backwash may be  such that initial head loss does not increase.  The em-
ployed backwash procedures are as follows.
1)  Backwash procedure for the uppflow filter
    An  example  of  a backwash program is  shown in  Fig. 3.1.21.  Here will  be
described the explanation of each stages.
                 Fig. 3.1.21 Time Schedule of the Upflow Filter Backwash
Time
Backwash Operat ion
<
o
~<
O
-o
o
u
1*
15'
t
f
£
I

20'
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3'
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06'
horg
3'









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e
30"
t



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30' 2
Air
200"
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I



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Wa
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4'




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er b
ash
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r
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ickw
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uent
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30"

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sh
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arge
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" 4'


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S



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rer b
rash
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i
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o :
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55'
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c
c
i
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i
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h Air

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.
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se V
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5
2'30"

                                      263

-------
i)    Backwash start: Filtration run is terminated on receiving the backwash start
signal and the pinboard timer start.
ii)   Water  drainage: When the backwash stage starts, the filter influent and effluent
valves close and the drainage valve  and the backwash waste water valve open so that
the water level in the basin lowers.
iii)   Air  blow start: After water level is read to be zero by the level meter (air purge
system) positioned  at 10 cm below the filter surface, another timer works and in
4 min. the air blower starts. During the air blow, the pinboard timer stops. Water in
the bed is completely withdrawn within 4 min.
iv)   Water  backwash start: in  2 min. after the air blow starts, a  backwash water
pump starts.  Because it takes some time until the air blower  achieves the deter-
mined flow. Backwash flow is as low as 10 m3/m2/hr. jn fjrst 5 mjn^ after ^en jt
increases up to 40 m3/rn2/hr. The time when the backwash flow changes from 10 to
40 m3/m2/hr. is synchronized  with the  end of the air blow.  The backwash in the
low flow has the purpose of extending the time of air-water phase as long as possible
and of discharging suspended solids  as much  as possible.
v)   Air  blower stop: When backwash  water level rises up to the point of 20 cm
below the top of the trough, the air blow stops.  This is so as to prevent the sand
media flowing out. The working time of the blower is generally 7 min.
vi)   Water  backwash stop: The backwash pump stops having worked for 10 min.
after its start.
vii)  Water  drainage: The  drainage valve opens simultaneously when the backwash
pump stops. Then,  all water in the bed is discharged with the same operation as the
step of ii).
viii) Air blow start.
ix)   Water  backwash start: Water is sent in the same procedure as iv), from the low
flow to the  general flow.
x)   Air  blow stop:  The same operation as iv), the operation  time  is almost 7 min.
xi)   Water  backwash stop: The operation time for the second water backwash is
2 min. longer than  that for the first water backwash.  It is continued for  12 min.
The longer time  is  taken with the purpose of completely discharging  suspended
solids and air remained in the filter bed.
xii)  Standstill time: The backwash operation is kept still for 2 min. after the back-
wash pump  has stopped in  order to  settle the filter media.
xiii) Filtrate discharge: An influent valve opens and a next filtration service starts.
But the backwash wastewater valve is kept open  during 5 min. and the first portion
of the filtered water is discharged from the trough.
xiv)  Termination  of backwash  process:  The effluent valve opens and the backwash
waste water valve closes. Then, the  next filter service starts.
2)   Consideration of the backwash system for the upflow filter
i)    The main consideration of the backwash procedure for the upflow filter should
be given  to  the final stage  of the backwash; stand still time. In this stage, the back-
wash operation is  paused after  the  backwash pump stops and the water level in the
filter  is maintained  as it is in  order to  settle down the sands expanded  during the
backwash process.  In view of dense packing of filter media, this stage has an impor-
                                     264

-------
tant relation with a breakthrough of suspended solid from the bed which is discussed
in the section (8). Then, the perfect compaction is intended by  opening the drain-
age valve and discharging the remained water. Moreover, to keep the drainage valve
open is effective to absorb the excessive high pressure caused temporarily when the
influent valve opens  at the rebeginning of filtration and to prevent the rapid change
of the pressure imposed to the sand media  for the purpose of its stabilization.  A
time requirement  to decrease the raw water contained in the headchamber (maxi-
mum  waterhead;  3.0 m) to the constant water level is the reason why the high pres-
sure is produced.
     Since  August 6, 1975, the following operation was added to the  final stage of
the operations shown in Fig. 3.1.21.  In  2 min. after the pause, the drainage valve is
opened.  When the water in the filter  basin is  discharged to just below the sand
surface, the influent valve is opened and the raw water of the amount for filtration
is sent in.  After  5 min. of discharging the filtered water out of the backwash waste-
water valve, the effluent valve opens and the filtration  starts again.
ii)   Increase of backwash water amount:  General flow is increased  to 1,400  m3/h
(0.78 m3/min.m2) for treatment of the raw  water with high turbidity.
3)   Backwash procedure for the tri-media filter
     Fig. 3.1.22  shows an example of backwash for  tri-media filter.  Here will be
described the explanation of each stages.
Fig. 3.1.22 Time Schedule of the Tri-Media
          Filter Backwash
Time

g1

*
0


<
s
•o
5





13-
30" Od'

32



2' ;
S
|
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ate

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Fig. 3.1.23 Time Schedule of the Tri-Media
         Filter Backwash
         (for High Turbidity)
(Tm^e)
Bockwosh
Operation
Valves
Opera t ion
? 10 20 c , 3,°
,.,„.., SurfoceWoshOmm) AirWoshdmm }
u, SurfaceWater
.| StortLevel
•5' Backwash Start
— "x,0"
2jO^
WaierBockwosh(4mm) Water Rock wo
Water OrQinoqe(3min)SurlocgWosr)
HypochlonteAdd.it
0°^? ^ ^^™?a^
ill tl[li
' 1 1 1 " ! | I
Influent Valve! Close )
Bockwash Waste Water Valve (Open)

WoierSiorogeOrnin,}
shfflmm)
j iause(imtn)
on(4mm) |7ppm 	
-

3^ 	 \34Surfoce WashVolve* V~\34

,25^ 	 ^'25" Backwash \'tti 	
V!25"
2<^ \20" water Drainage Valve

""V!^
30/\30' Air Vo
Filtrate Valve _(_Close )

ve(Close)
I40> 	

i)    Backwash start: On receiving the backwash start signal, the pinboard timer
starts.
ii)   Water drainage: The effluent and influent valves close and the backwash waste
water valve opens. Thereby, water in the basin is discharged.
iii)   Surface wash start:  The water level lowered to  the top end of the trough, the
level meter detects the water level and the signal is sent to start  the surface wash
pump. During this time the pinboard timer stops.
                                     265

-------
iv)   Water backwash  start:  1  min.  after the surface wash pump starts,  the water
backwash pump starts.
v)   End of surface wash: The surface wash pump stops after the 8 minutes' opera-
tion.  The surface washing and water back-washing works are simultaneously con-
ducted for 7 min.  This simultaneous operation is essential to prevent suspended
solids removed on the bed surface from producing mudball. Deficiency of surface
washing may cause mudball forming because the suspended solids remained on the
dead area of the bed surface agglomerate anthracite  particles.
vi)   Water backwash end: The water backwash pump stops working in 10 min. after
its start;  it  continues working for 3 min. more after the surface wash pump stopped.
This is for the purpose of discharging completely all the solids in the filter bed.
vii)  Operation pause:  The filter is  kept  still for a minute after the end of water
backwash in order to give enough time for the filter bed settling down.
viii)  Water storage: The  influent valve opens  and  the  backwash wastewater valve
closes. Then water is  stored until water level rises up to the level for a normal filter
service.
ix)   Termination of backwash: The filter backwash is terminated by opening the
effluent valve.
4)   Consideration of  the backwash system for the tri-media filter
     A major problem in  the  backwash system for the tri-media filter exist in the
slime production  in the filter material, especially in the sand media. This tack slime
production may cause the low fluidity of the filter media in the backwash  step so
that  an effective  cleaning of the bed can not be  achieved.  In order to solve this
problem, the backwash procedure was changed as follows.
i)    Sodium hypochlorite is added during the water backwash.
     When  cleaning is  repeated without an addition of hypochlorite, the slime is
produced in the sand layer and the fluidity of the sand is lowered. On this account,
the initial head loss gradually increases. The initial head loss increased about 10 cm
(Filtration  speed:  200 m/day) for  2  months  from June 4 to August 8, 1975 as
shown in Fig. 3.1.25.  This period  is  the season  when the temperature becomes
gradually higher.  Therefore, when the viscosity of water is lowered and the initial
head loss generally tends to decrease, we may conclude that this increase of the
initial head  loss  was not influenced by the  temperature.  The addition of sodium
hypochlorite started from August 8, 1975.  Its addition starts 2 min. after the full
opening of the backwash valves  and stops in 4 min. All the above operations are
automatically conducted. The adding point is just  before the backwash pipe enters
the filter basin. The added amount is 250 C/h (1.1  GPM). A percentage of effective
chlorine in  the sodium hypochlorite solution is 10% so that the chlorine injected
concentration is  17 mg/£.  As  the effective capacity of the storage tank of sodium
hypochlorite (made from F.R.P  added polyethylene, with the cylindrical  cap) is
2,0002 (528 G), the  supplement of the sodium hypochlorite is required  once 2
months for  the operation of two filter basins (a basin; 30 m3).  After the cleaning
with  an  addition  of sodium hypochlorite continued  for a  month since August 8,
1975, the initial  head  loss was lowered by 30 cm.  This has proved the effectiveness
of the above described  cleaning method.
                                     266

-------
ii)  Air-water phase cleaning
    Mixing cleaning of air and water is additionally performed after water is drain-
ed out of the basin.
    On August  16, 1975, the filtration of the raw water with  high turbidity has
begun (in mixing with the drained secondary sedimented  sludge).  After about a
month, the condition of the filter layer of one of the two basins has become worse.
SS accumulated  on  the anthracite surface layer was not cleaned  off, but  fell down
along  the  wall surface, and reached the supporting gravel layer.  It was found that
the cleaning system  shown in Fig. 3.1.22 has been insufficient for this kind of raw
water with high turbidity. Then, air-water mixing cleaning  was conducted and also
the quantity of backwash  water was increased up to  1,500 m3/h  (0.83 m3/min.m2)
(20 GPM/SF).  The quantity of air used for this purpose was  to be 15 Nm3/min. (0.5
Nm3/min.m2)  (1.64 GPM/SF). In this way  the raw water with middle strength of
turbidity was filtered from October 21 to November 3, 1975, but the above written
deterioration  of the filter performance was not  observed.  The altered  backwash
system is described in Fig.  3.1.23.
i)   Backwash start and  drainage:  On receiving the backwash start signal, the
filtration process is  ended and the backwash process starts.  In the first step of the
pinboard timer, the  influent and effluent valves close and the backwash wastewater
valve opens. This state is kept until the water level is lowered to the design level that
the surface washing  can be performed.
ii)   Surface wash and water  backwash: The first cleaning is  with the purpose of
flowing out SS  accumulated  on the surface  of the filter bed  and consists of 3
minutes' surface  washing and four minutes' water backwashing (overlap of  1 min.).
iii)  Drainage: The  drainage valve being opened, water level of the filter  basin is
lowered charged to the  bottom  out of the filter basin, in order to  perform the
following air-water mixing backwash effectively.
iv)   Air-water mixing  backwash: The air blower starts first, the backwash pump
starts next, and  the air-water  mixing backwash is performed  with pushing up the
backwash water  to  bed surface. The  air blower is driven only for a minute. Then
the water surface is just above the anthracite so that there is no  fear that the filter
media are carried over the trough.  The purpose of this air-water mixing backwash is
to clean out SS within the filter bed.
v)   Surface layer wash:  This is conducted by turning the surface washing equip-
ment  during the operation of the water backwash pump.  The surface washing equip-
ment  is to  be turned within the expanded layer of anthracite so that the water back-
wash, and  the cleaning of the inner portion of the  anthracite layer is performed
effectively.
vi)  Chlorine addition: The addition of sodium hypochlorite starts 2 min. after the
second backwash pump start and it continues for 4 min. The hypochlorite addition
is not sufficiently effective  in  the first backwash because  the large part of hypo-
chlorite is consumed by SS remained in the filter bed.
vii) Pause and water storage: After settling down the filter media, the influent valve
opens and the backwash wastewater valve closes.  Then water is stored  and after the
water level is  raised  to  the level for a regular filtration, the effluent valve opens and
                                     267

-------
the filtration starts again.
5)   Quantity of backwash water
     The design flow and  the actually used flow for the backwash of each filters are
presented in Table 3.1.10.

                       Table 3.1.10 Quantity of Backwash Water

the Updow
Filler
theTr.-Meckl
Flier

Backwash Water
(Raw Waterl
Backwash air
Surface wash Water
(Filtrate)
Backwash Water
(Filtrate)
Design Flow
per basin
300 m?H
I 200 .1
N - mVu
45 H
45"^"
m^H
(,100 H
per basin
IOmVH
40 ,,
.N-mfc
l.5m^H
367"^
Total
Amount
347 m3
N-rrtf
440
3
6 1
m3
172
 (3)   Initial head loss variation
      A head loss produced at the rebeginning of filtration run after the termination
 of the filter backwash is so called the initial head loss. The continuous investigation
 of the initial head loss testifies a degree of the filter bed cleaning.  If an ideal back-
 wash could  be  achieved,  an  increase of the initial head loss may not be observed.
 Adversely an increase of the initial head loss may indicate an incomplete cleaning of
 the  filter bed.  The  initial head loss variation  of the upflow and the tri-media sand
 filters from August 15, 1974  to March 15, 1976 was investigated.
 1)   Initial head loss of the upflow filter (Fig.  3.1.24)
     A stable condition of the initial head loss was observed until August 15, 1974.
 It might be associated with  a chlorine addition  of 3 mg/C to the influent.  After
 then, the chlorination of the influent was stopped to obtain a stable effluent quality
 and  a filter rate was increased to 400 m/day (6.8 GPM/SF), 500 m/day (8.5 GPM/
 SF), and 550 m/day  (9.4 GPM/SF).
     A rapid increase of the initial head loss was experienced in this test period.  So,
 chlorine solution was temporarily added to the influent on November 6. The initial
 head loss was maintained  to  be low for several days since  chlorine  was added.  But
 after that the initial head loss began increasing again rapidly.  In the previous wash
 system, the air blow had been carried out in the  condition that water was filled in
 the  filter bed.   In  the  modified  wash way, however, water is  discharged initially
 down to the bottom of the bed and the backwash is conducted from the low water
 flow to the regular water flow as described in the section of (2) - 1).  In this way, the
 initial head  loss was maintained to be low without the chlorine addition as shown in
 Fig.  3.1.24.
     From January 7, 1975,  the period of the backwash time was shorten to a  half
 of the usual one,  but  the low initial head loss was  not  maintained.  Also,  it  was
 found that a constant initial  head loss  could stably obtained by providing the back-
 wash once a day.  Moreover,  the  filter  was operated at the standard filter rate (200
 m/day) for  4 months from the beginning of June to the middle of October of 1975.
 In this period the initial head loss was constantly maintained at 30 cm.  This proves
 that the above suggested  backwash method can be applied for the practical  opera-
 tion.
                                     268

-------
   1.5
   1,0
°  Q5
                                               Fig. 3.1.24 Initial Head Loss Variation of the Upflow Filter
                      No. I Uptlow  Filler
                      No.2 Uptlow  Fi Her
                                          550 m/doy
                  5OOrn/doy
                               500m
                    }3OOm/doy
                           Improvement of  Backwash  Proced arefBac kwa «h  «tart»  after  emptying the ba i in)
                      400m/doy
                $
        300 m/day
                      200m/day
       Filter Rat*  100 m/d ay
             C h 1 p. r i n o Addition
                                                                                      No.I  3OOm/day
                                                                     Shorten  the  Backwash Period
Chlorine  Addition   Chlorine Addition
                                       Chlorine  Addition
                                                                                                                              9Om/day
                                                                                                                                    TO m/doy
    8/15 20233O9>» 9 14  19 24 2910/49 14 19 2'l 29 l»/1 6l'l 16 2\ 2612/1 6 II  16 21 2631 1/5 O 15 2025 3O2/4 9 14 19 2454 6 It  16 21 2631 4/9 10 15 2O 2530 5/9 IO
                                                                Mont h / Da te
E 1.0
                                      No. I  Upf low   Filter
                                      N o. Z  Upt 1 ow   Filter
                                                                          LV 423 m /da y
                                                                            .V
                                                                            LV 365-32D m/doy
                            LV 200 m/day
                                                                                                                Small  Flow   Flucfafion
                                                                                                    LVI90m/doy   LV |9om/doy  E*P«'
      LV70
       in/day
              LV IOO
               m/doy
                                   LV20Om/day   Large  Flow  Fluctuation   Experinenl
    5/9 10 1520 25 306/49 14 1924297/49 14 19 24 298/38 13  20 25 309/49 14 19 242910/49 H 19242911/38 13 18232812/3 IO 1520253012/4914 192429
                                                              Month/Date

-------
                                                 Fig. 3.1.2& Initial Head Loss Variation of the Tri-Media Filter
        1.5



     E

     V>

     o  I.O-
     _i

     •o
     O
     «
     I

     o 0.5
                               5OO m/day
                                                               No.I Tri- Media Filter
                                                               No.2Tr i - Wedi o Filter
                                                                                    No,2 4OO m/day
              IOO m/day

               (ihiorine  Addition
                                                                                 20O nn /day

           77jn/doy                                                                          IOO m/day

          Chiorine Addi tion  cyorion Addi t ion   Chjorion  Addition     Chior ion Addi ti o n
         8/15 20 25 30a4 5 14 19 242910/45 14 19 2429 ll/l 6 II  162126124611 16 21 2631 1/5 IO 12 20253O2/4 9 14 19 243/16  I I  16 2| 26314/5 IO 15 2025 305/510

                                                                         Day
o I.O
OQ3-
                   LV2OOm/da
No. I  Tri - Media  Filter
No.2 Tri-M «d ia  Filter
                                        BocKwasn by  Addition of Sodium Hypochlorite
                       Secondary Sedimentation
                           TanK  Drained  Sludge
                                                               V2OOm/doy LV2OOm/day
                                    Backwoshing Addition of Sadiun
                                                        Hypochlori t«

 Incomplete  Backwash ( Si multoneouj Bockwa sh of Two  Filters)

 Secodorv Sedlimenfation  TanK  Drained  Sludge Addition
Addition Backwash Layer (Stop  Filtration)      Incomplete   BackwashfSim
-	 -
                                                                                         LV 212 m/day""' taneouj Backwash  Two
                                                                                                               .     ri itGrs )
                                                                                                                    LVII7m/doy
                                                                         Backwajhing  by  Addition  of  Filratiofl
   5/5 IO 15 2O25306>»9 14  1924297/49 14 19 24 29 B/3 9 13 2O253O9A9 14 19 24 29IO/4& W 19242911/38 13 18 23 2'8I2> 6  l'l 16 21 26 3'l 1/4 5 IO 152025302/49141^243^5101*

                                                                            Day

-------
2)   Initial head loss for the tri-media filter (Fig. 3.1.25)
     In the operation  of the tri-media filter, no addition of chlorine showed an in-
crease of the initial head loss as well as in the upflow filter operation. A change of
the backwash system, in this case, was not effective  to prevent the initial head loss
increase. When the operation was performed with the backwash of once a day at the
standard filter rate (200 m/day) (3.4 GPM/SF), the initial head loss increased about
10 cm by August 8 (in about two months). Then, in the backwash system, sodium
hypochlorite was injected for 5 min. in 4 min. after the backwash start.  The injec-
tion rate of effective chlorine was 10 ppm.  The initial head loss was lowered about
30 cm on  August 9 in a month after this  backwash  start and since then the initial
head loss could be maintained at about 20 cm. Thus, the backwash system with the
addition of sodium hypochlorite made the stable practical operation possible for tri-
media filter.
 (4)   Filtration period and initial head loss
      Concerning the hourly variation of the filter head loss and the effluent tur-
bidity, the data  obtained  at a filter  rate of 300 m3/day (3.4 GPM/SF) are shown in
Fig. 3.1.26, which indicates that the effluent turbidities from the both filters  were
not influenced with  the  fluctuation of influent turbidity.  However,  there was a
great  difference between  the  upflow and  the tri-media filter with respect to the
 time period of filtration run that could be applied.  Fig. 3.1.27 shows the relation-
 ship between  a  terminal  head  loss  and the filtration period at various flow rates.
 The terminal head loss  means the head loss reached  at the end of the filtration run.
                       Fig. 3.1.26 Head Loss Variation and Turbidity
                                 Characteristics in the Upflow
                                 and the Tri-Media Filters
                    30i


                    25
                   _2O
                   E
JIG-


 S'

 0
                                                      oftheupflo»F»ter
                                                       the Tri-Media Fitter
                                                Influent Turbidity
                                                Enfluent Turbidity from the
                                                Upflow Filer
                                                Enfluent Tubidity from the
                                                 Tri-Medio Filer
                                       2050
                                      Fillrolion Period
                                                      ~30(hr!
                       I730&302330
                                 5.30  O30  I530 2030030  5'30 9 30
                                      Time
                                        271

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Fig. 3.1.27 Relationships of the Filtration Period and the Terminal Head Loss
            on the Upflow Filter Operation
   0 Hh-
                            FiI r e r  Rate
                                200 m/d
                                300 (Clzadded)
                                300
                                400
                               500
                         30        40        50
                                Filtra tion Period
        Fig. 3.1.28 Relationships of the Influent Turbidity and
                    the Filtration Period on the Tri-Media Filter
                       Filler Rare         Average Fi H ro r ion Period
                         200 m/d             27. 8hr
                   -      3O 0   (CI2 added )    t &. I
                         300                150
                         400                ,3.5
                         500                 5.9
                                        m
                    Terminal  Head  Loss  2,70
                         10                20                30
                                 Fi It ration  Period   (  hr )
                                   272

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              Fig. 3.1.29 Filtration Periods of the Upflow and Tri-Media Filter
                  Tri-Medio  Updo*
                          \  V
                                     - Terminal Head Loss
                             20     30    40     50    60
                                  Fi Itrahon Period   ( hr }
     At the beginning of the experiment, there was a difficulty to employ a high
terminal head loss because of some structural problems and  also a breakthrough
problem.  Subsequently, an instable terminal head loss was observed. The structural
problems were of the physical damages of the FRP trough.  They have been recon-
structed and now working well. The filtration periods applied to the tri-media filter
are presented  in Fig. 3.1.28.  Also, the average filtration periods  at various filter
rates are presented in Fig. 3.1.29,  which indicates that at  every rates studied the
upflow filter has a longer filtration period than the tri-media filter has.
(5)  Suspended solids removal capacity
     The removal  capacity of suspended solids in the experiment  performed from
August  15 to October 30 of 1974 (in  this period, a filter rate  was  varied in a range
from at 100 m/day (1.7 GPM/SF) to at 500 m/day (8.5 GPM/SF) was calculated by
using the following equation.
         M = Q(Trxrr-Tf xrf)   	(1)
Where,
     M
     Tr
     Tf
     rr
     rr
     Q
             Amount of SS removed in once filtration run (g)
             Average turbidity of influent (mg/C)
             Average turbidity of effluent (mg/C)
             A correlation coefficient of turbidity and SS in the influent (0.50)
             A correlation coefficient of turbidity and SS in the effluent
             A quantity of the filtered water during one filtration run (m3)
     The average turbidities  (Tr, Tf) were obtained by measuring the influent and
effluent turbidity at every 30  min. during the filter runs. The correlation coef-
ficients of turbidity and SS were obtained from Fig. 3.1.30.
     The amounts of SS removed by the upflow filter are presented in  Fig. 3.1.31
                                     273

-------
and that removed by the tri-media  filter in Fig. 3.1.32.  The figures indicate that
150 kg  (1.0 Ib/SF) of SS could be removed by one upflow filter bed (30m2) and
50kg of  it by one  tri-media  filter bed  (30m2) under the following operational
conditions, filter rate; 300 m/day, influent turbidity; 20 ppm, terminal head loss of
the upflow filter; 2.40 m.

                    Fig. 3.1.30 Correlation between Turbidity and SS
                                             I nfluenr
                                             Effluent
                                             Effluen1(Cl2 added )
                              Turbidity from the Turbidimeter (ppm )
                Fig. 3.1.31 Terminal Head Loss and Removed Suspended
                          Solids by the Upflow Filter
           i I o
                                       274

-------
       Fig. 3.1.32 Influent Turbidity and Removed Suspended
                   Solids by the Tri-Media Filter
                                   F il Ter Role
                                        200 m/d
                                        300  .
                                        400  >
                10      20      30      40      50      60      70 '    80
                                   SS removed  Uo. - s s/SO1"*)
Fig. 3.1.33  Influent and Effluent Turbidities at Filter Rate of 300 m/d
                                 ,>IOO
            30
               8/jB 19 20 21 22 23 24 25 26 27 28 29 30 31 %|  234  56
                                    Day
                                275

-------
(6)  Chlorine addition and effluent turbidity
     For the control  of  slime  generation in the sand filter, chlorine is generally
added to influent.  However,  the chlorine  addition  resulted in unstable effluent
quality.  Then,  chlorine addition was, principally  not  conducted and  also other
means such as  modifying the backwash system for the upflow filter and adding
sodium hypochlorite to the backwash water for the tri-media filter, were employed
for the slime control in this experiment.  Fig. 3.1.33 shows the turbidities variation
in the influent and effluent from the both filters. Since the chlorine addition to the
influents were carried out for the period from August 20 to August 31 of 1974, the
effluent turbidities of the both filters showed the fluctuation. This indicates that it
is largely influenced by the influent turbidity variation.
(7)  Head loss distribution in filter media
     Cross-section head loss distribution through the upflow filter bed are grafically
shown in Fig. 3.1.34 and 3.1.35. Also, Fig. 3.1.36 and 3.1.37 show the head loss
distributions of  the tri-media filter.  Fig. 3.1.34 shows that the graval layer at the
bottom of the bed can be an effective filter  medium in the upflow filter. It is also
shown by Fig. 3.1.35 that the suspended solids once caught by the supporting graval
layer gradually rise to the upper sand medium. The effective filter depth of the sand
medium above the graval layer seemed to be around 30 cm.
     Fig. 3.1.36  and 3.1.37 show that in the case of the tri-media filter, about 80%
of the total  SS removed was stored in the top layer of anthracite that was about 30
cm in depth. Both in the sand  medium in the upflow filter and the  anthracite
medium in the tri-media filter, the effective filter depth was about 30 cm.  However,
in the upflow filter, the graval layer at the bottom of the bed had an effective filter
function.  So that, totally,  the upflow filter is able to provide a larger SS storage
capacity than the tri-media filter.
             Fig. 3.1.34 Head Loss Distributions of the Upflow Filter (300 m/d)
              I 2

              I 3 •
                                      276

-------
Fig. 3.1.35  Head Loss Distribution of the Upflow Filter (400 m/d)
                       I.O       I.5
                       Head Loss
Fig. 3.1.36 Head Loss Distribution of the Tri-Media Filter (200 m/d)
                                          ( m- flq)
                            277

-------
             Fig. 3.1.37  Head Loss Distribution of the Tri-Media Filter (300 m/d)
(8)   Breakthrough problem on the upflow filter operation
     Filter breakthrough may refer to the phenomena that the stratified filter bed is
partially  broken and a water channel is temporarily made so that the stored SS  at
the bottom layer is released out of the bed during a  filtration run.  When the filter
breakthrough occurred, a heavy turbid water can be  observed above the surface of
the filter bed and the filter head loss lowers rapidly. After a while, the breakthrough
will spontaneously disappear and the head loss will increase again.  However, when
the head loss increases to the point that the last breakthrough happened, another
breakthrough may  occur  again. Then, if  the breakthrough once  happened, the
filtration run must be terminated to start the backwash operation.
     The initial  head loss and  head  loss at the breakthroughs occurred since the
operation start till the present time are investigated and presented in Fig. 3.1.38,  in
which the term of normal head loss means the initial head loss shown while the filter
rates were at  300  m/day  (5.1 GPM/SF) and 400 m/day (6.8  GPM/SF) and the
successful backwashing of the filter  bed was carried out from January  25 to Feb-
ruary 24 of 1975. Fig. 3.1.38 indicates that the following two may be considered  as
the reasons why the breakthrough phenomena happen.
1)   A sufficient decrease of the initial head loss may not be achieved  due to the
deficiency of the filter backwash (in the case of 300 m/day).
2)   Although the initial head  loss is low enough, the standstill  step at  the end  of
the backwash operation may not be provided (in the case of 300 m/day and 400
m/day).
     A stress generation in the grids was measured by mounting a strain gauge on the
grid. The head  loss observed  at the beginning of the stress generation was ranged
from 1.70m to 1.76m (from 5.6 to 5.8 FT), as presented in Table 3.1.11.
     Fig. 3.1.38  also indicates  that the head loss at the time of breakthrough occur-
ring was above 1.80 m (5.9 FT).
                                     278

-------
     A mechanism of the  breakthrough phenomena may be explained as follows,
based on the above investigations.
     As the amount  of stored SS  increases and the clogging of the filter media
proceeds, the  sand layer may receive the upward force which is larger than the
weight of the sand bed itself. Then, when the sand particles in the top sand layer are
uniformly arranged, the inverse bridge is formed with the grid and the force  to push
the sand bed up may be transmitted from the sand medium to the grids.  Thus the
sand layer can support this force.  But when the  backwash is insufficient and the
sand particles  are coated with slime, or when the compaction of the sand layer by
the pause stage is insufficiently performed, the resistive force due to the engagement
of the sand particles can not be expected and the upward force might be released
through the portion of the sand  particles.  Eventually, the breakthrough  of the re-
moved suspended solids may take place.

                  Fig. 3.1.38 Head Loss at the Time of Breakthrough
                            Occurrence and Initial Head Loss
                        Normol heod loss
                                I 5             20            25 (ml
                                      Head  Loss that Breakthrough Occured
                                                           300m/day
                           N o rmal head loss
                                              20            2 5(m)
                                       Head Loss that Breakthrough Occured
                    Table 3.1.11 Head Loss when Stress Generated
                               in Grid
Measure
Dote|974
Head Loss
(ml
I2-IO
I.7I
12- 13
1. 73
12 -20
1. 76
12-24
I.7I
12 -27
1.73
12-29
1.70
                                       279

-------
(9)  Consideration of the filter media used in the tri-media filter
     Generally, suspended solids of influent are removed at the top layer of the tri-
media filter, as' described in  the section of (7).  Then in order to extend a filtration
period, an effective depth of the filter must be increased.  One of factors to extend
a filtration period may exist in  the particle size of anthracite in the top layer of the
filter media.
     Conventionally  the anthracite with an effective particle size of 1.22mm  (uni-
formity coefficient 1.41)  was  employed.  The  anthracite  with an effective size of
1.70mm  (uniformity coefficient 1.21) was to be  employed  instead of the above.
Column test was carried out by using two columns filled with  the  anthracite of two
particle sizes  (The other  media are equal to the  existing ones).  Test results are
shown in  Fig. 3.1.39.  It indicates that the larger particle could increase the filtration
duration as 1.7 times longer as the smaller one.

                       Fig. 3.1.39 Effects of Particle Size of Anthracite
                                  for  the Tri-Media Filter
                            (Cml
                            350
                             50
                I975.I/28-I/29
              No I Filter
              Anthrocile E S I22mi
              Averoge 423 myd
              Slope dM/dl = !75»IO
                                            N02 Filter
                                            Anthracite e S I 22mm
                                            Average 427 m/d
                                            Slope dM/dl- 0 98x10
                                              q	 Influent Turbit V
                                              .—. NO-1 Effluent Turbity
                                              «— N02E.f f lu ent Turbity
                                      10       20
                                     Filtration Per lOd f hr)
                         Fig. 3.1.40 Head Loss Distribution After the
                                    Change of Anthracite Particle Size
    {m m)
  2-   °
     too
  ''  200

| 4-  300

5   I*™
5   O
„ 6- ,_ 6OO
_i
_ 7- ,
  8-
                        800
                        900
                     9- IOOO
                                    Filter Rate 2OOm/doy
                                    Anthracite Particle Size |.70mr"
                                    Anthracite Head Loss    2.60m
                                   " Total Filtration Pressure  0.284 rfoy cm2
                                   f Filter Rale200m/day
                                   Anthracite P
-------
     According to the above tests results, about 76% of the anthracite medium of
the tri-media filter (32 cm of 42 cm anthracite medium depth) was exchanged with
the larger anthracite with the  effective  size 1.70mm.  Fig. 3.1.40 shows  that the
anthracite with the effective particle size of 1.70 mm admits the deeper SS invation
and the filter media are found to be more effective.
(10)  Practical filter rate
     To determine  the  operational  filter rate, the  decrease  of an amount of the
effluent caused by the backwash is not taken into consideration. Then, the follow-
ing equation was used for obtaining a practical  filter rate,  which is termed as the
filter rate that the  backwash time requirement and the amount of the backwash
water are taken into consideration.
         Q=24 T
         v      Tf
                   F - W
                                                           (2)
where,
     Q
     F
     W
     Tf =
     Tw =
Practical filter rate (m/day)
Filter flow rate per unit surface area (m3/m2)
Backwash flow rate per unit surface area of the tri-media filter
(It is not required for the upflow filter.) (m3/m2)
Filtration period (hrs.)
Backwash period (hrs.)
     The  filter flow  rate, F  is expressed by  using the operational filter rate, Q'
(m/day), as follows;
          F =
               1
              24
      Q'xTf
(3)
     From the equation (2) and (3), the relationship of the practical filter rate and
the operational filter rate is expressed by the following equation.
              Q' Tf - 24W                                              m
          \J     rr-i   i-pi         ...    	    	  •  *•  *    * * ' *  V  /
                if + lw
     Calculation results by using the above equation are presented in Table 3.1.12.
It was proved that the upflow filter was superior to the tri-media filter both in the
practical filter rate and in the operational filter rate.
                          Table 3.1.12 Practical Filter Rate
Operalcnal
Fi Her Rare
m /day
200
300
400
500
Practical Filler Role (m / rj )
theUpflow Filler
AH : 1 80m
197 ( 15 )
293 (23)
367 [ 3 2)
478 (44)
£H" 2 70m
198 I 1.0 )
295 (171
391 (23)
482 I 3 6)
The Trj-MsdmFilter
AH : 2 70m
193 (35)
285 150)
378 155)
464 (72)
                        All numbers overoged 40 data of o filter
                                       281

-------
(11) E. coli behavior in the filtration process
     Usually, about 75% E. coli removal could be achieved by the both filter sys-
tems as shown in Table  3.1.13.  Furthermore, it was  very rare case that  E. coli
number in the effluents exceeded 600.  Then, when the sand filter is employed for
the treatment of the secondary effluent, the chlorination of the filter influent may
be unnecessary.

                     Table 3.1.13 E coli Removal Characteristics
Dole
5/2I
10 00

13 30
5/27
1 1 00

13 00

15 00
6/13
9 00

II 00
II 05
14 00

16 00
Influent
Cohlorm










11,10"

5,10*

5 , 10

II, 10"
E Coli
no

660

520

500

1300

800
2 400

2500

2 300

1 900
the Upllow F Iter

"'no™









26.10=
( 76)
9,10=
( 62)
Filter
37, I03
(75)
8*I03
(75)

E Coll


146
(72
330
! 34 )

450

(65 )
620
( 74)
500
(80)
Bodrwosh
520
(77)
480
[ 75)
2
Conform









25
148)
38, 03
(75)
9,10'
(74)
Ecoll
II 3
183)






3-fo
(56)
600
175)
510
(80)
560
175)
440
( 77)
the Tri-Medio Filter
1
=**









29,10s
74)
24, D
(59)
42X1C?
(72)
33
-------
 ured with the turbidity meter of falling type of Swiss Sigrist company (UP 52-TJ).
 Calibration  of this turbidity meter was conducted by means of silicon dioxide (SiO2
 1 mg/£ = 1 ppm). Calculation of SS removal was executed based on Fig. 3.1.41.
           Fig. 3.1.41 A Relationship between Turbidity and SS when the Sludge
                    withdrawn from the Secondary Sedimentation Tank is Mixed.
                              80

                              70

                              6O
                              3O

                              20

                              IO
August 27 of I975
                               0   IO  20  30  40 55  60
                                      Turbi di i y (mg/l)
2)   Experiment result
     Experiment was  performed as indicated in Table 3.1.14 and the hourly varia-
tion of SS removal is shown in Fig. 3.1.42 and Fig. 3.1.43.
              Table 3.1.14 SS Removal Experiment at High Turbidity Influent
Exper
-imen
Name
U- I.I
U- IZ
U- 13
U- L4
U-L5
D- f.l
D-I2
D — 13
D- \A
0-I5
D-I6
Filter
Nome
U-l
U -I
U-2
U-2
U-2
D-l
0-2
D-l
D-2
D-2
0-2
Start
Dote 1
Time
75 9/4
I 1 :3Z
759/5
I 7 34
75-9/5
4. I 6
75 9/5
IS 27
73.9/15
6:30
75.9/6
0 51
75 9/5
21-49
75-9^
IO:26
75 9/5
1 05
75 9/6
T'08
75 9/5
10 32
Average
Filter
Rate
(m/doy)
195.4
195-1
201 0
1994
1966
196 7
197 1
197 5
196 0
198 1
196 9
Filter
Run
15 13
II .56
13 .19
1 1 10
10 '38
9 .16
9 .00
8 '27
9 '08
8 :37
10 -59
Head
Loss(m)
223
242
270
270
2.67
300
2.70
270
205
270
260
Average
Turbidity
(ma/1 )
304
464
34 1
472
4| B
46.6
503
392
374
424
42.4
Effluent
Average
Turblaiiy
(ma/1)
100
191
120
1 12
0.60
3.17
158
162
109
104
175
SS
Cop'ured
(kg/tni)
3.53
4.91
385
494
427
3.78
3.64
292
293
126
377
                             U- I Upflow Pilfer No. I
                             U-2   -    >,  No 2
                             D-l T n-Medio Filler No I
                             0-2    „     No 2
                                       283

-------
Fig. 3.1.42  SS Removal Variation of the Upflow
          Filter
Fig. 3.1.43  SS Removal Variation of the
          Tri-Media Filter
                                                          2345
                                                           Captured  SS  (kg-ss/m2 )
3)   Consiederation
i)    Amount of SS captured
     The  amount  of removed SS  at  the  time of low turbidity (average influent
turbidity; 17.5 mg/E) and  that at the time of high turbidity (average influent tur-
bidity; 40 mg/fi) were almost equal as for the upflow filter as indicated in Fig.3.1.44.
     The  value is  120 ~  150 kg/30 m2 (4 ~  5 kg/m2) (0.8 -  1.0  Ib/SF) in the
terminal head loss of 2.70 m.
     With regard to the tri-media filter, while the SS removal amount was 30-70
kg/30 m2  (1.0  ~ 2.3 kg/m2) (0.2 ~ 0.5 Ib/SF) at the  time of low  turbidity (anth-
racite particle size; 1.22mm), the  removal amount at the time of high turbidity
(particle size; 1.70mm) increased up to 90- 110 kg/30 m2 (3.0-  3.7 kg/m2) (0.6
- 0.8 Ib/SF), as shown  in Fig. 3.1.45.  The head loss distribution comparison in the
case of anthracite size; 1.70  mm  and 1.22mm of Fig. 3.1.40 indicates  that the
increase of head loss was limited to the anthracite layer when the particle size was
1.22mm,  but the  head loss increase reaches the sand  layer when it was 2.70mm.
Therefore, in the filter media  of the anthracite particle size of 1.22 mm, SS removal
was small and in the case of the particle size of 1.70 mm,  the anthracite layer and
the sand layer  works effectively for SS removal so that the larger part of SS was
removed.  Amount of  SS  removal  of tri-media filter  is rather  inferior to that of
upflow filter: about 70 - 80%.
                                     284

-------
Fig. 3.1.44 SS Removal of the Upflow Filter       Fig. 3.1.45 SS Removal of the Tri-Media Filter
          (200 m/day)                                  (200 m/day)
Sao,
E
                    ' High Turbid I ty
                    i Low Turbid i ty
                   IOO       ISO      200
                 Captured  SS  f hg-ss/30 m2 }
                                                                         Anthracite I. 70
                                                                               1.20
                                   Captured b s 'kg/30m3]
ii)   Effluent turbidity
     Fig. 3.1.46  presents the turbidity  of influent and effluent investigated  every
one hour.  The turbidity of effluent from the both filters were higher at the start of
filtration than those of later stage of the runs.  The degrees of this deterioration of
effluent turbidity were  greater in the tri-media filter and  also the  time required for
recovering the stable turbidity is longer in the tri-media filter.
           Fig. 3.1.46  Turbidity of Filtrate to the Influent Containing High Turbidity
                      (Filter Rate 200 m/day)
                                                       Inf lueni Tur bidity
                                                       Effluent Turbidity
                                                       (NoJUpnow Filter)
                                                       Effluent Turbidity
                                                       (No.2Upfldw Filter)
                                                       Effluent Turbidity
                                                       (No,l Tri-media Filter)
                                                       Effluent Turbidity
                                                       (No,2Tri-media Filter)
                                                     (.013
                          I 15 18
                          i Ooy
21 0 3 6 9 12 15 18 21 0 3 6 9 12 15 18 21 (Hour)
  5th Day         6th Day
iii)   Filter bed condition
      No variation was observed in the outer appearance of the filter bed against the
high turbidity influent as to  the upflow  filter.  In this experiment six tests  were
executed and the head loss was augmented to above 1.70 m, but no break of the bed
occurred during these runs.
                                         285

-------
     In the tri-media  filter, however,  SS accumulated on the anthracite surface
invades along the wall face and the filter bed condition deteriorates.
     Since the general washing method could not recover the original condition of
the bed and the following operations became necessary.
i.    The backwash water containing chlorine of high concentration (sodium hypo-
chlorite 500 mg/£) was sent to the filter and the chlorinated water was stored to the
level right below the trough.
ii.   Air  blow is  performed. The chlorine remaining in the filter bed disappears in
15 min. of continuous air blow.
iii.   The  water staying in the  upper layer of anthracite was lowered down to the
filter bed by opening the drainage valve  and again the air blow was performed.
iv.   SS dissociated  from the filter  bed was washed away by the backwash water.
     The operations of i ~ iv are repeated in correspondence to the necessity.
     When much SS remained in the tri-media filter bed, the filter.could not suffi-
ciently fluidized during its washing and masses of SS accumulated in a certain part
of the bed or  the surface of anthracite layer piled up. However this extreme deterio-
ration  of filter bed condition did not cause any initial head loss increases. This was
because the influent passed through  the SS accumulated part with of resistance than
other parts in  the beginning of filtration.  Thus, the effluent  quality became worse
just after  the filtration start as above described. It seemed that, after a while, the SS
accumulated part became  densely  packed, and the  effluent  quality  stabilized.
Therefore, the best  method to find  the deterioration of filter bed condition is the
observation of surface of anthracite layer after water drainage.  When it was difficult
to remove  SS  remained in the filter  bed, the hand operation  of breaking masses  of
SS with a  bar during the backwash  along  with the  above  i ~  iv was also effective.
The  backwash method executed once  a  day  was  changed to that shown in Fig.
3.1.23 so as to treat the high turbidity influent.
(13) Filtration through the upflow filter at  the large flow fluctuation
,)   Experiment  method
            Fig. 3.1.47 Wastewater Flow Variation in the Treatment Plant (1974)
                     35000,

                   _ 30000
                   -§20pOO$5i
                     I 5000
                    : I 0.000
                     5000
-•-•- D ecember - Februor y
-<*-°- March -May
-X-K- June-August
•**• September-November
— Average
&*J>.
                         910 II 1213 1415 1617 18 1920212223241  2345678
                                         Time  (hour)
                                      286

-------
                   Table 3.1.15 Flow Fluctuation Curve (No. 1)


9
10
I I
I 2
13
I 4
15
1 6
I 7
i e
1 9
20
2 1
22
23
24
1
2
3
4
5
6
r
e

Flow Rote
ImVhrT
356
45O
5 IS
553
544
506
459
431
413
422
431
450
469
469
469
450
403
328
281
234
210
197
188
244
Filler Rote
(m/doy)
285
360
412.5
4425
435
405
3675
345
330
337.5
345
360
375
375
375
360
3225
2625
225
187.5
168
1 575
ISO
195
Observed Value
Flow Rate
( m3 / h r I
345
452

560

520
-
420
412
410
420
452
480
480
480
452

306
-
205

168
150
216
Filter Rate
(m/doyj
276
36 1 .6

448

41 6

336
329.6
328
336
361.6
384
384
384
361.6

244.8
-
164
-
134.4
120
172.8
    The maximum filtration  rate was taken at 443 m/day which was maximum
filtration rate possible for one filter operation.  Applying this rate for the annually
averaged  maximum flow rate  per hour of a flow fluctuation pattern in a certain
sewage treatment  plant shown in Fig. 3.1.47,  the flow rate of the other time was
determined in correspondence with this pattern. Thus, the supposed value of flow
fluctuation curve (No. 1) in Table 3.1.15 was obtained.  The ratio of the maximum
to the minimum flow was 3.7 : 1.  The  control of flow rate against the supposed
value  was executed by changing the water level  of the raw water conduit. The water
level change of the raw water conduit was performed with  changing the  setting of
influent flow regulator sending the signal to  the influent  flow  control  valve by
remote control. The  signals to this regulator was sent by the flow indicator which
could  send 96 types  of analogue signals in 24 hours. Accordingly, the signal was
cascade changed once 15 minutes. The water  level is determined  on the following
equation;
                                	(3)
where,
    a
    C
    Ho
    H
 = OaV2g(H-Ho)      	

Bellmouth sectional area 0.0707 m2  ( 300 m/m)
Flow coefficient
Bellmouth height (height above the bottom of influent conduit)
Water level of influent conduit
Gravity acceleration
Flow (m3/sec.)
                                    287

-------
     Based on the water levels (H,, H2) in the two flows (Q,, Q2) different to each
other, C and Ho of each filters determined as follows;
               No. 1 filter       No. 2 filter
         C      0.7725           0.7620
         Ho     0.203m           7.196m
     Flow  was measured by  electro-magnetic flow meter and water level by water
level meter of air purge type.
     The experiment of large flow fluctuation was to be executed in No. 2 filter and
the enumeration equation of flow was obtained;
         Q = 0.7725 x 0.0707 x 2 x 9.8 (H-7.196)
                         Q
            = 7.196
                             )2
                      0.2385
     When the unit of Q is m3/H,
          H = 7.196 J-'  Q   ^
(4)
                                                                      (5)
                      858.6'           	
     The observed values  in Table 3.1.15 were obtained by calculating the water
level for each flows with the equation (5), setting it in the flow indicator and meas-
uring the actual flow.
     The experiment  was conducted in the  flow variation pattern of this observed
value.  Flow variation pattern of the calculated  value and the observed value are
presented in Fig. 3.1.48.

                     Fig. 3.1.48 Large Flow Fluctuation Pattern
                  "300
                  ll
                  I! 200
                  i_

                   ICO
                              --x	x~- Calculated Value
                              —o—o	 Observed  Value
                     9 10 II 12 13 14 15 16 17 18 19 20 21 22 23 24 I  234 567  89
                                     Time ( hour)
                     37 41 45 49 53 57 61 65 69 7377 81 85 89 93 | 5 9 (3 17 21 26 29 33 37
                                     Dial No of Flow Designer
2)
     Experiment result
     This experiment was performed totally for ten times as shown in Table 3.1.16.
The break phenomena occurred three times of these ten.  In RUN-2 and 3 it occur-
red when  the  flow increased rapidly  at the high head loss.  In RUN-4, it occurred
when the  normal backwash was not  performed due  to the  fault of the pinboard
timer.  In RUN-5 ~  7, the head loss did not rise up to above 1.70 m within 24 hours.
When the  head loss rises above 1.70 m, the stress was observed in the grid and the
filter bed got into the break zone condition status.  In  RUN-8 ~ 10, though the head
loss was above  1.70 m, no break occurred because the period of rapid flow increase
was applied for the filtration start.  Therefore, it  was found that the break of the
upflow filter occurred when the head loss was above  1.70 m and the flow increased
suddenly.   Incidentally,  the  break  might be  caused  also by those  instantaneous
                                      288

-------
change of flow rate by means of cascade  control.  It, however, is now being investi-
gated  on permissible range of flow fluctuation.  The hourly variation of the head
loss, the flow rate and the  influent quality for every run  is shown in Fig. 3.1.49
through 3.1.53.
                      Table 3.1.16  Experiment on Large Fluctuation
                                   of Flow to Upflow Filter No. 2
Expenm
NO,
'
2
3
4
5
6
7
6
9
(9)
IO
Date
75KV2I 9-45-KV2I 17:30
10/22 IS 15-K>22 835
10/22 ro-is-io/zss^s
10/23 1445-KV24 2)45
10/28 6-00*0/29 I5-.I5
10/29 15OO-IO/30 BXX)
10/30 I7-QOHO/3I I7OO
10/31 B-.I5-II/1 1300
ll/l I4OO-I1/5 1605
UI/4 9 15-11/5 16-15)
11^ I&00-M/6 I&20
Filter Run
Time
hr.: m i n )
7 45
13 50
23 3O
12 00
24. 15
24 00
24-00
18' 45
98:15
(31:00)
22.20
Turbidlty(overage)
Influent
(mg/1 1
31
32
10
23
7
9
1 2
1 6
7
(7)
1 7.5
W/efj
1
1
0
1.3
I
1
1
1
•cl
«l )
I
Max Heac
L«?
2.50
2.90
2ft 6
2.40
0.80
093
1.20
2.64
261
(2.61)
d»v<3.00
Observa
-tlons

Breakthr
-ough at
the HeoO
Loss ol
2J90
Breakthr
-ough at
the Head
L°2"46f
Breokihr
-oughof
the Head
Lois of
2.40
Incompl
-lere bock
wash)
Airwoter
mixing
wash)




*w.l 14.00
-Nov. 4
09-15'
Constant
i»


    Fig. 3.1.49 Experiments on Large Flow
              Fluctuation No. 1, No. 2
            Fig. 3.1.50 Experiment on Large Flow
                       Fluctuation No. 3
    !•
       — Filler Rate
       -*— Influent Tur bid
       -—Effluent Turbidft
500 _


40O"-
  E

300 =
  (E

ZOO •
  \L
IOO
             —~- Filter Rdie
               - Influent Turbidity
               - Effluent Turbidity
             -•4- Head Lois
                                                  D II E S H CI6 1718 B 20 21 22 23 24 I 23456789  (Hour)
                                          289

-------
Fig. 3.1.51  Experiment on Large Flow Fluctua-
            tion No. 4 (Incomplete Washing)
                                       Fig. 3.1.52 Experiment on Large Flow
                                                   Fluctuation No. 8
  40 -j





 I30



 £20-
               — Filler Roie
               —— Influeni Turbiduy
               —— E(flueni TurDidity
               -•-*-- Head Loss
          IS 16  17
       Oct 23,19^5
 20 21  22 23 0  I  2  3{Hour>
rime         Oci24
                                              —- Filler Role
                                              ^Influent Turbidity         ^
                                              -!-Effluenl Turbidity       -V
                                                 Heod Loss         .0<%

                                                              ^f-'
                                                             *»"«*
                                                                            300^
                                                                               £

                                                                            200 5
                                                                               a

                                                                            100 £
                                                            18 19 2O 21 22 23 0  I ? 3 4 5  6 7 G 9 10 II 12 !3(Hour)
                                                           OCI3I         Novl Time
                    Fig. 3.1.53  Experiment on Large Flow Fluctuation No. 10
(14) Filtration through the upflow filter at the small flow fluctuation
1)   Experiment method
                             Fig. 3.1.54  Small Flow Fluctuation Pattern
                                     --<—K-- Colculored Value
                                     —<^-°	 Observed Value (No.I)
                                     —•—•— Observed Value ( No.2 )
                           IOO


                             0
                             9 10 II 12 13 14 15 16 17 18 19 20 21 22 23 24 I  234  56769
                                                  Hour
                           No 37 41 4549535761 65 67 73 7781 85 8993 I  5  9 13 17 21 25 29 3337
                                                  Diol No.of Flow Set-up
                             0  I 2 3 4 5 6 7 8 9 10 II 12 13 W 15 16  17 18 B 2021 2223
                                                  Absolute Hour
                                                290

-------
     The maximum flow of 300 m/day (the maximum filter rate of two filters
operation)  was applied  for the peak flow of Fig. 3.1.47 and the filter rate of each
time zone  was obtained in a similar manner as in the foregoing experiment and
presented in Fig. 3.1.54.  A part of the  filter rate could not lower as calculated
because of the limitation from facility construction and resulting in ratio between
the maximum and the minimum value in the actual flow rate of 2.4 : 1 (No. 1 up-
flow filter) and 2.3  : 1 (No. 2 upflow filter).
2)   Experiment result
     With regard  to the low turbidity influent, 20 times of the experiment were
performed  for  No.  1 upflow filter and  24 times for No. 2 upflow filter, as shown
in Table 3.1.17 and 3.1.18.  Some hourly variations of them  were presented  in
Fig. 3.1.55 ~  3.1.57. These results  prove that when the head loss is below 1.7 m,
breaks does not occur in spite of the variation of the flow velocity.
Table 3.1.17  Experiment on Small Fluctuation
           of Flow to Upflow Filter No. 1
Table 3.1.18 Experiment on Small Fluctuation
           of Flow to Upflow Filter No. 2
Experlm
-enf
NO.
I
2
3
4
5
6
7
e
9
10
I [
12
13
I4
15
16
(7
ie
19
2O
21
Date
51-
1/21.18-53-1/23,16-22
1/23,16:53-1/24,22:17
l/24£ JO6-I/26 ( 4 . 33
1/26, 5:23" I/27,IQ:45
1/27,1 1-35-1/28,17:09
1/28/7: 59-l/29,23--22
l/30p-13~l/3l, 5.46
1/31,6' 36~2/ 1, 12:OO
2/1,12:50 -2/2,18:15
2/219:06-2/4 , 0-41
2/4,1-31-2/5,7:07
2/5,7:57-2/6,13-30
2/6J4'-2l-2/7,l9-42
2>T£O-32~2/9 , 1 : 54
2/9,2-44- 2/10.8- OS
2/t£ 59-2/11,1423
2/1 M5:i3~ 2/I2£O-3a
2/^22 128-2/W, 3--02
2/W, 3 35-2/15, 9:27
2/I5JO-1 7-2/1 6,15 39
4/9,16 X>5-4/O, 6 38
Filler Run
Time
4322
29.24
29^25
29:22
29-34
29:23
29:33
2* 24
29:25
29:35
29:36
29-33
29-21
2922
29-24
29=24
29:25
2934
2934
29:22
14-33
Turbidity( overage)
"t'rnW
9
4
3
2
3
3
4
3
4
4
5
7
5
6
5
6
6
7
6
5
20
EWo7V/
2.
I
1
1
1
1
I
1
1
I
1
2
1
1
1
1
1
,
1
1
2
Max. Head
Loss
Q75
0.58
a 67
0.68
0.61
0.56
0.67
O-62
0 61
0.61
0.66
0.69
0.59
0.64
0.62
061
059
0-67
O63
0.59
1.90
Observo
-flons




















Break
Occurred
laperim
•enf
NO.
1
2
3
4
5
6
7
e
9
IO
1 1
12
13
14
15
16
I 7
ie
19
20
2 1
22
23
24
25
Dare
51-
l/2Y7-O4-l/23,2O-45
1/2321:50-1/25, 2 45
1/25,359-1/26, 8 3O
1/26,927-1/27,14 25
1/27,1 5U7-UZ6, 20 U3
1/28,2 IS6-1/30, 3:40
^30, 4-32-1/3 1 , 9 32
1/3 1,1023-2/1 , I5'I2
2/1,1603-2/2, 2O53
2/2,2144-3**, 245
2/4.3:36-^5, 758
2/5,8^49-2^, 436
2-€,5-.27-2/7 , I'I6
2/7, 2 --08-2/7, 2151
2/7,22 42-2-3, IS34
2/8,19.25-2/9, I5'O7
2/9,15-59-2/10, 11-49
2^0^40-2/11, 8:26
2/11, 9:17-2/12, 5:04
2/1 2, 536 -2/13, C44
2A3, 236 -2/13, 22. 18
2/l325O9-e/W, 1 9:OO
2/14,1951-2/15, 15.34
2/15,16-25-2/16, 12: 15
4/320.3O-4/9, 1 1:35
Filter Run
(hrmln)
49:54
28:55
28 46
28:58
28 '56
30.35
39 00
28 49
28 SO
29:01
28:22
19.47
1 9 49
19:43
19.52
19 42
19. 5O
19 46
1 9-47
1 9 48
1 942
1 9.51
19 43
1 9. 5O
15.05
Turbldlryfoverage)
'TrW
9
5
3
2
3
3
3
3
4
4
5
8
5
5
6
5
6
6
6
6
6
6
6
5
21
Euvw
5
4
2
2
2
2
3
3
3
3
3
4
2
2
J
2
2
2
I
2
2
2
2
2
3,5
Mo, Head
LfS,',
0-9O
079
Q83
0.70
0.66
O7B
083
069
065
Q75
073
0.77
Q67
0,61
060
063
062
064
0£5
066
0.57
Q59
0.6O
Q6I
2.70
Observe
•floni

























                                      291

-------
  Fig. 3.1.55 Experiment on Small Flow
            Fluctuation (No. 2 Upflow
            Filter, Low Turbidity)
   (m)
   20,
— Filter Role
-<- Influent Turbidiry
-— Effluent Turbidity
'•*" Head Loss
                                   30O™
                                      E
                                   200 £
                                      ir
                                   100 2
    3579
    Jon25
 13  15 17 19 Zl 23 I  357  9 (Hour)
            Jon 26
                                  Fig. 3.1.56  Experiment on Small Flow
                                             Fluctuation (No. 1 Upflow
                                             Filter, Middle Turbidity)
                                              5O|2p
                                 30

                                -§20
                                J3
                                3
                                "-IO
        Filler Rote
        Influenl Turbidity
        Effluent Turbidity
        Heod Loss
 IS I7 ©  19 20 21 22 23 0 I  2  3
April 9, I975     Time
                               400

                               3001
                                 E
                               200 £
                     Fig. 3.1.57 Experiment on Small Flow Fluctuation
                               (No. 2 Upflow Filter, Middle Turbidity)
                               —  Filter Role           .^
                               -—  Influent Turbidity     o* V
                               -—  Effluent Turbidity    
-------
(16) Comparison of turbidity meters for automatic measurement
1)   Experiment method
     The following three  types of turbidity meters were employed in this experi-
ment;
1.   Turbidity  meter,  Hokushin Electric Works (N),  W301-WLS301 (Open liquid
surface scattered light method)
2.   Ultrasonic washing type turbidity transmitter, Yokokawa Electrics (Y), TYPE
8562 (Scattered light and permeable light operation system)
3.   Turbidity  meter,  Swiss Sigrist (S),  UP52,  (permeable light and standard light
comparison system)
     Secondary settled sludge was mixed into the secondary effluent (SS lOmg/C)
from March 3 till April 10 of 1976 so as to increase the turbidity and then the indi-
cated values by the above three turbidity meters were compared.  Sludge was added
four times on March 3, April 13, April 5 and April 9  ~ 10 and the each turbidities
are indicated in Fig. 3.1.58 ~ 3.1.62.  The indicated value of each turbidity meters
in the secondary effluent are indicated in Fig. 3.1.63.
Fig. 3.1.58 Comparison of Turbidity Meter
         (High Turbidity)
      Morch 3 . I976
Fig. 3.1.60 Comparison of Turbidity Meter
         (High Turbidity)
-50,
a>
E
"40
April 5, I976
   17   6   15   14   [3   12   II    10   9(Hour)
                                  Fig. 3.1.59 Comparison of Turbidity Meter
                                           (High Turbidity)
                                          Fig. 3.1.61 Comparison of Turbidity Meter
                                                    (Fluctuation of N Company Base)
                                           30

                                           20

                                           10-
                                         April 9, 1976
                                                  23   22   21   20   19
                                                          Time
                                       293

-------
Fig. 3.1.62  Comparison of Turbidity Meter
          (Fluctuation of N Company Base)
Fig. 3.1.63 Comparison of Turbidity Meter
          (Low Turbidity)
                April 10, I976
                                                Morch 3. I976
                                                               Apn ] 8. I976
                                               a   8   7   6    12
                                                                     10   9   SlHour)
2)   Experiment result
i)    The indicated value of N and S are stable at the time of low turbidity (below
10 mg/2). The indicated value of Y has an irregular fluctuation.  (Fig. 3.1.63)
ii)   S and Y  are excellent in the longtime stability.  In case of N, the fluctuation of
the base is found in  Fig. 3.1.63. This is because SS is accumulated in the bottom of
the tube  forming the rest  water surface,  the  water depth  becomes  shallow and
irregular reflected lights augment.  On  April  10, the turbidity of N  rose, finally
reached  100% and did  never  return. When SS accumulated at the bottom of the
tube was removed by flashing with city water,  it became to indicate  the normal
value.
iii)   S was the most excellent, N was the second and Y was the worse in the range of
turbidity fluctuation.
(17) Particle size distribution in the effluent
     Particle size distribution of SS contained in the secondary  effluent and  the
filtered water was measured by  HIAC fine grain meter and shown in Fig. 3.1.64 ~
3.1.66. Fig. 3.1.64 shows about the filter rate of effluent from the usual secondary
treatment plant  at the filter rate of  500 m/day with the  inlet turbidity of 14 mg/e
and Fig. 3.1.65 shows the filtered effluent at the filter rate of 200 m/day which the
secondary  drained sludge was mixed into the secondary effluent.  The number of
particles sized below  10 jum was not largely different between the mixed raw waste-
water and the secondary effluent, but for the particles of the size above 10/urn the
number was much larger in the mixed raw wastewater.  In both cases, the number
contained in the filtered effluent was smaller than in the influent in the range of the
particle size  above 7.5/urn.  This shows that  the particle size of SS  removed  by
filtration  is above 1.5 urn.  SS above 7.5/um of the carry-over  from the secondary
clarifier can also be removed.
                                      294

-------
Fig. 3.1.64  Particle Size Distribution (Middle
            Turbidity)
Fig. 3.1.65 Particle Size Distribution (High
            Turbidity)
                                  46 I25


No.SUpflow Filter
Influent No. 1 Trl Mcd
]rri rn
i n
i y
Fll >e

I5000-,


-
E

IOOOO






5000




0












	

V ^S "~
^ r^
r^ ^
^ ^ d







3 F Iter


9000"

80 OO
Rote 5OOm/doy







































31




















_7000
E
o
6OOO
5000.

4000



3000


2000

IOOO

bi

Sep. II, 1975
No.lUptlow Filter

























nfluent ' No.2
n E
ul
i 	 1 ti_
30 0-i


1

LJ
1.0 (

Filter Rote 200














~




N
\
\
\
\
\
\
\
\
\
\
\
\
\
\
\


1 —

























^-
\
\
\
\
\
\
\
\
\
\


-




frl-Medla


mg/ 1 )

Ti/doy






































\
\
\
\
Filter






















"1
1
-







































^T_,
\l 1




•S.
















































^h
          4-5    5-75    75-10   (0-15
                Particle Size
                                                             4-5    5-75    7,5-IO    IO-I5    15 -I50(/>m)
                      Fig. 3.1.66  Particle Size Distribution (Low Turbidity)

2OOOO






I5OOO
e






^'OOOO












5OOO







0














































































^,
\
\
\
\
\
\:
\
\
\
\
\
\
\
\

\
\
\
\

\
\
\
\
\
\
\
\
\
\
\
\
\
\
\
\






































t





































pr





































1








\
\
\
\
\
\
\
\
\
\

\
\^
\
\
\
\
\
\

\
\
\
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\
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7,







p





























1976























































—



















S S
1 | Influent 3 3mq
^VJNolUpf low Filler 1.3
|" [NolTrimediQ Filter 2 Q





















•^H
\

\

\
\
\
\
\
\
\ \T — i
\ \ VI 	 ,
\ \ \h
\ \ o
\ \ Ci 1
                                           5- 7     7- 10    10- 15     15  ( j
                                                 295

-------
 (18) Boring investigation of upflow filter media
 1)   Method
     As to the upflow  filter operated continuously for two years after the intro-
 duction of water, the boring investigation was performed on the filter media (two
 places), all the filter sand were carried out and the investigations of the supporting
 sand layer and the water nozzle were executed. This investigation had the purpose
 of  finding out the  quantity of the foreign matters which was not removed  by  the
 traveller screen (opening of 6 mm) mounted in the entrance of the raw water tank,
 entered into the filter and caught in it.
 2)   Result
 i)   No foreign matter was found in the filter sand and the sand itself was clear.
 ii)   The  particle size of the filter sand tends to  become smaller along with  the
 operation.
 iii)  The foreign matters (vinyl strips etc.) in the supporting sand layer are slight and
 tend not to be accumulated.
 iv)   Choking  of water  nozzles caused by the  foreign matters contained in  the in-
 fluent was not observed.
 3.1.3  SUMMARY
     Coagulation-sedimentation filtration experiment and  the  comparison experi-
 ment of the upflow filter and the downfiow filter have shown summarily the follow-
 ings;
 a.   Coagulation-sedimentation filtration method is  effective for  the removal of
 phosphorus, BOD and SS.
 b.   Direct filtration method is sufficient for only  BOD and SS removal.
 c.   Flow proportion control method is enough for the alum addition to perform
 the coagulation-sedimentation treatment.
 d.   Increase of the filter rate up to 500 m/day  (8.5 GPM/SF)  did not have any
 adverse effect to the effluent quality and also to the systems operation.
 e.   No difference in the effluent quality was observed between the upflow and the
 tri-media filter.
 f.    The average removals of SS and BOD were 90% and  80% respectively.
 g.   In this study, the optimum backwash procedures have been found for the both
 filter systems.
 h.   Amounts of SS removed were about 5 kg/m2 (1.0  Ib/SF) through the upflow
 filter  and about  3.7  kg/m2  (0.8  Ib/SF) through the  tri-media  filter (anthracite
 particle size of 1.70 mm).
 i.    The  supporting gravels of the  upflow filter effectively  functioned  as filter
 media for  SS removal.
j.    Breakthrough problem in the upflow filter during constant flow filtration was
 perfectly solved by adopting the adequate washing  method.
 k.   When Hows rapidly fluctuate during high head loss stage of filtration runs, sand
 bed break may occur. However, this can be overcome and prevented by countering
 operational procedures.
 1.    The  anthracite  of  about  1.7mm in its  effective  size is advantageous to  be
 employed  in the tri-media filter.
                                      296

-------
m.  The practical flow rate of the upflow filter was larger than that of the tri-media
filter.  This realizes that the upflow filter has the larger SS removal capacity from a
practical point of view.
n.  Removal of E. coli can be expected through filtration.
o.  The upflow filter has an advantage that the observation of the effluent quality
and that flying out of generated chironomus can be prevented by the filter bed.
p.  SS removal at the filtration of high turbidity influent is almost equal to that at
low turbidity but the backwash must be carefully conducted.
q.  The size of particles that can be removed by filtration is above 7 nm.
r.  Choking of water nozzles was not  observed in the upflow filter and the sup-
porting sand layer was also kept clear.
                                     297

-------
3.2   FILTRATION STUDY AT THE  KYOTO PILOT PLANT
     The fallowings  are a summary  on the suspended solid removal  by filter and
carbon contractor at  the Kyoto pilot plant.
     The section -  3.1.1  - deals with the solid removal by filter  of secondary
effluent  and alum precipitated effluent under varying influent  flow.  The sewage
inflow into  a treatment plant varies every moment. Its variation is extremely great
from a low in the night on dry weather to a high on storm weather.
     There are two possible ways to  meet the inflow variation — one, the constant
filtration with flow equalization ponds and the other, the varying filtration allowing
the influent flow variation.  Because  of a omission of a flow equalization pond, the
varying filtration is superior to the constant filtration, if there is no great difference
as to the quality of effluent and the suspended solid loading  between the two.
This report sums up the results from October, 1975 to March, 1976.
     The section — 3.1.2 — is a study on the possibility of removing both organics
and solids by granular carbon. The influents for testing here are filtered secondary
effluent, secondary effluent and tertiary alum precipitated effluent.
     In this method,  there are questions as mentioned below.
1)   Is the necessary  filtration run length expected by carbon layer?
2)   Is the suspended solids in the effluent satisfactory?
3)   Is there a drop  in organic removal efficiency of carbon by accumulated solids
on the surface or in the micropore of carbon?
4)   Is there a drop  in carbon regeneration efficiency by accumulated solids on the
surface or in the micropore of carbon?
     The feasibility of this method could be judged when the necessary information
is  obtained. There had been no  detailed report  on this method in this country.
Then the  Public Works Research Institute began the study  on this method on
November 8, 1976, by using carbon contractors at the Kyoto pilot plant.
     This report is  an interim report summing up operational results in the two
month  period  from  November to December, 1976,  Some data obtained  on the
questions, No. 1, 2, 3 is contained in this report.  A study on the question No. 4 is
planned for February, 1977.
                                     298

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3.2.1   SOLID REMOVAL BY FILTER  UNDER VARYING  FLOW
a.    Experimental Procedure
     Table 3.2.1  shows the specifications of the gravity, down-flow type filter used
for this experiment  at the Kyoto pilot plant.  There are two filters of the same
specifications,  one is for the secondary effluent, and the other is for the effluent
from alum precipitation.
                         Table 3.2.1  Specification of Filter
                   Filter
Surface Area (m2)
1 .0 x 1 .2 =
1.2
                   Filter Media
Grain
Size
Depth
(mm)
Anthracite
Sand
Anthracite
Sand
Total
E.S. (mm)
U.C. (mm)
E.S. (mm)
U.C. (mm)
1.62
1.33
0.61
1.26
625
375
1,000
                    Support Media
Grain Size (mm)
19.1-12.7
12.7 -6.73
6.73-3.36
3.36-2.00
Total
Depth (mm)
50
50
50
50
200
     A flow-rate pattern transmitter is set to give flow variation.  The circuit for
controlling the inflow to the filter consists of two elements. One is the feedforward
control of revolution numbers of the roots pump connected to the effluent pipe of
the filter. The control works by electric signals from the above mentioned flow-rate
pattern transmitter.  The other is the feedback control by electric signals from the
level meter, which is set on the triangle weir for the effluent flow measuring.
                                     299

-------
     Fig. 3.2.1  shows  the  flow variation used for this  experiment.  The variation
represents a typical  pattern of the inflow into the Toba Sewage Treatment Plant
where the pilot plant is located.
                            Fig. 3.2.1  Flow Variation
  o
  a
  c
  o
                                    Average
                                   —i—
                                    10
—i—
 12
—r~
 14
—i—
 16
18    20    22
                             24
Time
1
2
3
4
5
6
Filtration
rate ratio
0.832
0.731
0.668
0.606
0.534
0.459
Time
7
8
9
10
11
12
Filtration
rate ratio
0.616
0.721
0.904
1.242
1.301
1.301
Time
13
14
15
16
17
18
Filtration
rate ratio
1.281
1.278
1.275
1.294
1.265
1.268
Time
19
20
21
22
23
24
Filtration
rate ratio
1.248
1.147
1.058
1.058
0.983
0.960
     The filtration is terminated when the total head loss reaches 3 meters.
     The turbidity in both influent and effluent was measured  continuously by the
surface-scatter type turbidimeter and  then the turbidity was converted into suspend-
ed solids through the relation  of suspended solids to turbidity shown in Fig. 3.2.2
and Fig. 3.2.3.
                                      300

-------
   20
   15
en
oo
   10
              Fig. 3.2.2  Turbidity ~ SS (Secondary Effluent and Its
                         Filter Effluent)
                     O  Secondary effluent
                     •  Filter effluent of secondary effluent
                  SS = 0.976 • Turbidity
                                                    SS = 0.898 • Turbidity
                        5               10               15

                                   Turbidity (mg/C)
20
              Fig. 3.2.3 Turbidity ~ SS (Alum Precipitation Effluent
                        and Its Filter Effluent
                   O Effluent from
                      Alum Precipitation
                   • Filter Effluent of
                      Alum Precipitation
                      Effluent
                              10       15      20

                                 Turbidity (mg/K)
                                   301

-------
     In discussing the experimental results, suspended solids are calculated from an
average turbidity in every one hour from  the beginning to the end of each case of
filtration (a weighted average with filtration flow rate in the case of varying filtra-
tion).  And the suspended solid loading is expressed by  [g-SS captured/m2 •  sec-
tional  area  of filter]  and obtained  by average suspended solids  in influent  and
effluent, filtration run length and filtration flow rate.
     The total head loss was measured continuously by the level meter and the head
loss in the  filter bed was measured at 10:00 and 16:00  at the depths of 10, 30, 50,
75, 100 cm from the surface of filter media.
     The washing of a filter consisted of nine minutes  of surface washing (0.2 m/
minute), nine minutes of back washing (1.03 m/minute) and seven minute overlap of
the two washings.
     The expansion ratio of media by backwashing was set at 20%.  And the washing
water volume needed for above condition was 11.2m3.
b.   Filtration of Secondary  Effluent
     Fig. 3.2.4 is the  relationship between suspended  solids in the influent  and
effluent. It shows that suspended solids in the effluent increase with the increase of
those in the influent.  Also  seen  in the figure is the presence of two groups with
distinct difference in  filtration flow rates. Group-A is of the rates of 180, 300,
420 m/day by constant filtration. Group-B is  of the  rate of 500 m/day by constant
filtration and of the  average  rates  by varying filtration of 300 m/day  (flow rate
range, 138  ~ 390 m/day) and 420 m/day (flow  rate  range,  193 ~  546 m/day).
                      Fig. 3.2.4 SS Removal by Filter
                              (Influent: Secondary Effluent)
c
u
3
   5-
   4-
3-
.S   2-
00
            y = 0.381 -x+ 1.006
               r = 0.969
               N= 12
                                        = 0.387-x
                                         r = 0.931
                                         N= 11
                                                     0.020
o Constant 180 m/day
n Constant 300 m/day
AConstant 420 m/day
•Constant 500 m/day
• Varying 300 m/day
A Varying 420 m/day
                                                                   —i—
                                                                    11
                                                         —i—
                                                          10
                                                                          12    13
                                   SS in influent (mg/C)
                                      302

-------
When the relationship  of suspended solids in the influent and the effluent in each
group is assumed linear, the regression lines obtained are:
Group-A   [SS in effluent (mg/C)]  = 0.387 x [SS in influent (mg/C)] + 0.020  . . (1)
Group-B   [SS in effluent (mg/C)]  = 0.381 x [SS in influent (mg/£)] + 1.006  . . (2)
     The SS removal of Group-A obtained by eq. (1) is about 61% regardless of the
SS in the influent.  The gradient of eq. (2) almost equals to that of eq. (1). However,
the intercept of eq. (1) is about zero against about  1 mg/£ of eq. (2). This  means
that the SS in the effluent of Group-B is by about 1 mg/C higher than that of Group-
A regardless of the SS  in the influent.  Accordingly,  in Group-B, the SS removal as
calcurated by eq. (2) increases with the increase of the SS in the influent, standing at
42, 49, 54% respectively against the SS in the influent of 5,8,  12  mg/C.
     For a comparison between constant filtration and varying  filtration, take the
filtration flow rate of  300, 420 m/day common to the two methods. In this case,
the SS of the effluent by varying filtration is estimated to be higher by about 1 mg/C
than that of the  effluent by constant filtration when the SS of the influent is the
same.  Because constant  filtration belongs  to Group-A and varying filtration to
Group-B.  However, it  must be noted that varying filtration with an average rate of
300 m/day has the maximum rate of 391 m/day. Therefore, when only filtration
rates are taken into consideration, it is hard to conclude that the effluent quality by
varying filtration is worse than that by constant filtration. It is  considered that the
true problem lies in the change of filtration flow rate itself.
     Fig. 3.2.5 shows the SS loading in  the case of  the total head loss  set at 3 m.
The SS loading increases with the increase of the SS in the influent. However, at the
flow rate of 500 m/day, this tendency ends when SS in the influent exceed 10 mg/C.
The SS  loading also differs with the change in filtration flow rates.  The readings at
the rates of 180, 500 m/day are evidently smaller than those at the  rates of 300,
420 m/day.  For example, when the SS in the influent is  7.5 mg/C, the SS loading
for each of the rates of 180, 300, 420, 500 m/day is about 2,300, 3,500, 3,500 and
2,300 g/m2 respectively.

                      Fig. 3.2.5 SS Loading of Filter
                               (Influent: Secondary Effluent)
             4,000
             3,000 -
         3
         .f  2,000 -
             1,000 -
o Constant 180 m/day
D Constant 300 m/day
A Constant 420 m/day
• Constant 500 m/day
• Varying 300 m/day
A Varying 420 m/day
                                    5   6   7   8   9

                                     SS in influent (mg/f)
                                                      10  11
                                                              12  13
                                      303

-------
     Fig. 3.2.6 shows an example of the relationship between solids in the washing
waste and the washing time being obtained by the same procedure mentioned before.
(Fig. 3.2.7)  The SS  loading obtained  from Fig.  3.2.6 is 2,700 g/m2.   This value
should agree with the SS loading captured by the filtration. However the former
loading  exceeds  loading about  20%  more than  the latter one (2,300 g/m2). Only
one example is shown here. But  more study is planned for turbidity measuring of
washing waste.
                            Fig. 3.2.6 Filter Washing
  5= C
   ~
  rt
2 i

1

0
     800
     700 -
     600.
   O<>
   ~5o
     500-
   c
   '4
   :fl
   C
   C/3
     400 -
300-
     200-
      100-
        Surface
       washing
     (0.2 m/min.)
                         Surface and back washing (1 .23 m/min.)
                                                               /• j Q^ -
                                                            1_
    0    1
                          34567
                                  Washing time (min.)
                                                            10   11
                                     304

-------
                       Fig. 3.2.7 Turbidity ~ SS (Filter Washing Waste)
                   Turbidity   150
                   SS= 11.87 xTurb. +31.90
                   r = 0.917
                   Turbidity > 150
                   SS = 10 t1
                   r = 0.947
                  100        200         300         400
                                    Turbidity (mg/C)
500
600
     Fig. 3.2.8 is the relationship between suspended solids in the influent and the
filtered volume.  It shows that the filtered volume by constant filtration and varying
filtration is almost the same at the flow rates of 300, 420 m/day.  Accordingly, at
the rates of 300, 420 m/day,  the comparison between the SS loading by constant
filtration and that by varying filtration is reduced to the comparison of the amount
of SS removed.  For example, in the case of 7.5 mg/£  of SS in  the  influent, the
amount of SS removed obtained from Fig. 3.2.4, are 4.6 mg/C for constant filtration
and 3.6 mg/2  for varying filtration.  Therefore, the SS loading by varying filtration
at the rates of 300, 420 m/day is about 80% of that by constant filtration (3.6/4.6 =
0.78).
                                      305

-------
                       Fig. 3.2.8 Filtered Volume
                                (Influent: Secondary Effluent)

"E
m
E
S""*"
£
"o
13
£
£



1,200
1,000 -

800-

600-

400 -

200-
0
A
ADA A
°4
• _
o • D •
00 •
o Constant 180 m/day
n Constant 300 m/day * 9
A Constant 420 m/day • Varying 300 m/day
• Constant 500 m/day A Varying 420 m/day
1 	 1 	 1 	 1 	 1 i i i i i i i i
31 234567 8 9 10 11 12 K
SS in influent
     Fig. 3.2.9  gives the relationship between  bed depth and the average increase
ratio of the head loss in filter beds during constant filtration. The head loss increase
ratio here is expressed by the ratio of the value of head loss minus initial head loss at
a selected depth of filter bed against the similarly obtained value at the filter media
depth   of  1,000 mm.   The   figure  shows   considerably  difference  existing
in the forms of suspended solids capturing,  depending on filtration flow  rates.
     At the rate of 180 m/day,  the form of filtration is the  typical surface filtration
with the head loss increase ratio standing at 78% in the anthracite surface layer and
at a mere 1.5% in the anthracite-sand border and sand layers combined. At the rate
of 300 m/day, the head loss increase ratio is still fairly high at 64% in the anthracite
surface layer, but the ratios are almost uniform  in the layers below. At the flow rate
of 420 m/day,  the  ratio drops to 41% in the anthracite surface layer and the per-
centage is 22 in the anthracite-sand  border, indicating that  solids are removed more
uniformly in every filter bed layer than in other rates. In the case of 500 m/day, the
head loss increase ratio in the anthracite layer becomes small, while the ratio stands
at 54% in the anthracite-sand border layer.
     The finginds would allow  the estimation  that filtration of  secondary effluent
by the filter media composition used this experiment, depends on the surface layer
at the rate of 180 m/day, on all layers at the rate of 300 ~ 420 m/day and  on the
sand layer at the rate of 500 m/day.  Because of the reason mentioned above, it
seems, that the  SS loading is small at the rate of 180 m/day,  that the effluent quality
is  a  little bad  and SS loading is  also small at 500 m/day and  that both effluent
quality and SS loading are good at the rates of 300 and 420 m/day.
                                      306

-------
                          Fig. 3.2.9 Head Loss ~ Filter Media Depth (Influent :  Secondary Effluent)




1}
'o
s
• _c
- c
.<







•o
c
on



0
10

20 -
30
1=
0
x 40 -
OH
U
•a
ra 5Q
•a
E
£60.
u.
70 -
80 .


90 -
100
X/X/////X///X/X//
^^^^^ ?? 5%
y/^
A ».»
^
w

3.8%
f



1.2%




Filtration rate
°-3% 180m/day


                                                                                    4! 4%
                                                                             14.1%
                                                                            9.5

                                                                               21.8
                                                                             13 -2
Filtration rate
 420m/day
0     20    40    60    80   100    0    20   40     60    80   100     0   20    40    60    80   100     0    20   40     60   80   100

                                                  Increasing ratio of head loss (%)

-------
     Hour-by-hour measurement of the head loss in filter beds in the varying filtra-
tion has not yet been carried out.  In this way  of filtration,  an average speed of
420 m/day has the speed range from 193 to 546 m/day, thus covering all filtration
forms by constant filtration - the surface filtration, the in-depth filtration and the
sand layer filtration.  The hourly change of head  losses in the varying filtration will
be observed in the future.  And the observation may explain the reason why the
effluent quality by varying filtration is worse than that by constant filtration.
                Fig. 3.2.10 The Time When the Total Head Loss Reached 3 m
Cumulative frequency of the time when
the total head loss reached 3 m. (%)
to 4* <^ OO O
o o o o o o



N = 47

I | 1 I 1 1 1
47





62





68




68




68





70





81






85






91





100








till
     §   1
             -\	1	1	1	1	1	1	1	i	1	1	1	1	1	1	1	1	1	1	1	1	r
           123   45   678  9   10  11  12 13 14  15  16 17  18 19 20  21 22  23 24
                                       Time (hour)
     Fig. 3.2.10 shows the rationship between, the time of filtration termination in
varying filtration and its cumulative frequency. The data used for this figure are not
limited to the results obtained in the period of this experiment. The filtration start
time was from 9:00 to  16:00. According to the figure, the times of the total head
loss  reaching  3 meters  are limited to the  closing periods of filtration  flow  rate
increase and at the times of high filtration flow rate.  Especially noteworthy is that
about  half the  filtration runs stop in the  closing period  of filtration  flow  rate
increase or within  one  hour from  9:00.   See one example of varying filtration in
Fig. 3.2.11.
                                       308

-------
                                                    Fig. 3.2.11  Varying Filtration
O
U,
    600-
     500-
    400 -
     300-
     200 -
     100-
3 -
A	A Filtration rate
        Total head loss (m)
        Turbidity of influent (mg/8)
                                                                                                Turbidity of effluent (mg/fi)
                              12   16   20    24   28   32   36   40    44   48   52    56   60   64    68   72   76
                                                             Run length (hr.)

-------
     The results above indicate the possibility that in varying filtration, filters reach
to the terminal head loss almost at the same time, during the time of influent flow
rate increase, and the necessary capacity can't be maintained.  In such a case, wash-
ing of the filters at the time of low influent flow or other preventive means would
become necessary.
c.   Filtration of Tertiary Alum Precipitated Effluent
     Fig. 3.2.12 presents the relationship between suspended solids in the influent
and in the effluent.  It shows that suspended solids in the effluent increase linearly
along with the increase of those in the effluent.  And there is no great difference in
the effluent quality between constant filtration at the flow rates of  120 ~ 300m/
day and varying filtration at the rate of 180 m/day.  The regression line obtained
from the figure is:
         [SS in effluent (mg/B)] = 0.521 x [SS in influent (mg/B)] -  0.360  ... (3)
     The SS removal obtained through eq. (3) is 66, 60, 55, 52, 50, 49% respectively
for each SS  in the influent of 2, 3, 5, 10,  20, 30 mg/B.  This means that the lower
the SS in the influent is, the greater the removal becomes.
             Fig. 3.2.12 SS Removal by Filter (Influent: Effluent from Alum
                       Precipitation of Secondary Effluent)
     16
     14-
     12-
     10-
      6-

      4-

      2-

      0
y = 0.521-X-0.360
    r= 0.987
   N = 33
                                         Constant 120m/day
                                       0  Constant 180m/day
                                       °  Constant 300m/day
                                       •  Varying 180m/day
                            10   12   14  16   18   20   22  24  26   28   30   32

                                  SS in influent (mg/C)
     Fig. 3.2.13 shows the SS loading at the total head loss of 3 meters.  The loading
increases with  the  increase of suspended  solids in  the  influent.  There also is no
evident difference in the SS loading between constant filtration at the rates of 120 ~
300 m/day and varying filtration at 180 m/day. The regression line is:
          [SS loading (g/m2)]  = 66 x [SS in influent (mg/B)] +320	(4)
                                      310

-------
               Fig. 3.2.13 SS Loading of Filter (Influent: Effluent from Alum
                          Precipitation of Secondary Effluent)
           2,800

           2,600 -

           2,400 -

           2,200 -

           2,000 •

           1,800

           1,600 •

           1,400 •

           1,200 •

           1,000 -

            800 -

            600 -

            400 -

            200 -

              0
                0
= 66x + 320
 r= 0.927
 N = 33
                                     a Constant 120m/day
                                     0 Constant 180m/day
                                     ° Constant 300m/day
                                     • Varying  180m/day
                                    10   12
                                             14   16   18   20
                                             SS in influent
                                                             22  24   26   28   30   32
     Fig. 3.2.14 is the relationship between suspended solids in the influent and the
treated volume at the total head loss of 3 meters.  The curve in the figure is calcu-
rated through eq. (3) and eq. (4) in accordance with the following equation.

                 Fig. 3.2.14  Filtered Volume (Influent:  Effluent from Alum
                            Precipitation of Secondary Effluent)
          400
          300
          200
           100 •
                          u a    o o n
                                                             a Constant I 20m/day
                                                             0 Constant I80m/day
                                                             D Constant 300m/day
                                                             • Varying  I80m/day
                                   10   12   14   16   18   20  22   24   26   28  30   32
                                         SS in influent (mg/S)
                                           311

-------
                                             [SS loading (g/m2)]
                     ,     /•  a /  2 M  — 	|,uu njquiiis V6/1" j\
          [Treated volume (m /m )]  -  ss influentrSS in effluent
                                                           (5)
                                       L(g/m3)
                                     L(g/m3)
     The treated volume obtained by eq. (5) shows that the less suspended solids in
the influent are, the more  steeply the treated volume increases below a point of
10 mg/C of suspended solids in the influent. Above the point, the decrease in  the
treated volume caused by the increase in suspended solids in the influent is not very
sharp.
     Judging from the data obtained under the conditions of this experiment, it can
be concluded  that varying  filtration is not less efficient than  constant filtration in
terms of the effluent quality and  the  SS loading in the  case of filtration of alum
precipitated effluent.
     Fig. 3.2.15 shows the relationship between  the filter media depth and  the
average head loss increase ratio  obtained from the head loss distribution in the filter
bed  during constant filtration.  The head loss  increase ratio  here means the same
as defined in a.

                Fig. 3.2.15 Head Loss~ Filter Media Depth
                          (Influent: Effluent from Alum Precipitation of
                                  Secondary Effluent)
          0

          10

          20  -I
          30
       f.40
       15  50
       £
       £60-1
         70

          80  -
         90  -
         100
6.4%
                  9.3%
 3.1%
                                  65.6%
      15.6%
  Filtration rate 120 m/day
7.7%
                                    4.5%
  3.0%
                                                   62.8%
    22.0%
   Filtration rate 180 m/day
             0    20   40     60   80   100    0    20    40    60    80    100
                                Increasing ratio of head loss (%)
                                      312

-------
    According to the figure, the head loss increase is almost negligible in the anthra-
cite layer but it occurs in the anthracite-sand border layer, standing at 65.6% and
62.8%  respectively for  120m/day and 180m/day of the filtration flow rate, or
almost 2/3. This means that most floe in the effluent from alum precipitation passes
through the anthracite layer and  is captured by the sand layer.  This tendency is
recognized  even  in the  relatively  low filtration flow rate  of  120 and 180m/day.
Therefore, a conclusion is that anthracite with the effective  size of 1.62 used for this
experiment is too large for the filtration of the alum precipitated effluent.
3.2.2   SOLID AND  ORGANIC REMOVAL  BY CARBON CONTACTOR
a.   Experimental Procedure
    The carbon contractors used  for this experiment are the gravity, down flow
type contractors with  a sectional area of 0.7 m x 1 m = '0.7 m2   The height of
carbon filled is 3 meters. The water level above the carbon is 2 m.  The underdrain
is the Leopold Block.
    There  are  six contractors, two each place  in a series.   Influents are  filtered
secondary effluent for the No.  1  contactor, secondary effluent for the No. 3 con-
tractor and the tertiary alum precipitated effluent for the No. 5 contractor.
    The carbon for the primary contractors (No. 1, 3,  5)  is X-7000, which is
spherical carbon  made of coal by Takeda  Pharmaceutical  Company Ltd,.   The
carbons for the secondary contractors are Calgon-SGL for  the  No. 2  contractor,
Calgon-CAL for the  No. 4 contractor and Takeda's Shirasagi for the No. 6 con-
tractor.
    The primary contractors are for the study of suspended solid removal. X-7000
is used for  them, because the X-7000 has a relatively large effective size (1.21  mm)
and a small uniformity coefficient  (1.32) among  brands of carbon now available on
the market. Table 3.2.2 points to considerable difference existing in the effective
size and  the uniformity coefficient from one brand to the other.  The choice of
different brands  of carbon for the  secondary  contractors is for the continuation of
carbon regeneration experiments, which have already been conducted four times.
                  Table 3.2.2 Activated Carbons Used for the Experiment

Mesh
E.S. (mm)
U.C.
Total Surface (m3/g)
lodin Number (mg/g)
Methylene Blue Number
(mB/g)
Material
Shape
Takeda
X-7000
8x32
1.21
1.32
900- 1,200
950- 1,150
180-200
Coal
Spherical
Takeda
Shirasagi
8x 30
0.82
2.02
970
950
180
Coal
Crushed
Calgon
SGL
8x30
0.72
2.06
980
950
170
Coal
Crushed
Calgon
CAL
12x40
0.52
2.00
1,065
1,000
200
Coal
Crushed
                                     313

-------
     The filtration flow rate for the experiment is 240 m/day (LV = 10) in constant
filtration and 240 m/day on the average in varying filtration.  The variation of vary-
ing filtration here is identical to that on Fig. 3.2.1.  The run is terminated when the
total head loss reaches 5 m.
     The suspended solids was obtained by measuring turbidity with  the surface-
scatter type turbidimeter and feeding the turbidity to the equations on the relation-
ship between suspended solids  and turbidity.  The equations are (cf. Fig. 3.2.2,
3.2.3):
     for secondary effluent
         [SS (mg/£)] = 0.969 x [turbidity  (mg/C)]
     filter effluent of secondary, effluent  contactor effluent of filtered secondary
effluent, contactor effluent of secondary effluent.
         [SS mg/C)] = 0.878 x [turbidity (mg/C)]
     effluent of alum precipitation
         [SS (mg/£)] = 1.303 x [turbidity  (mg/C)]
    contactor effluent of alum precipitated effluent
         [SS (mg/C)] - 0.975 x [turbidity  (mg/C)]
                         Fig. 3.2.16 UV Absorbance ~ TOC
                                  TOC = 24.95 x UV + 3.44
                                  r = 0.907
                                  N = 23
                          I	"	1	1	1	1	r
                     0   0.1    0.2   0.3    0.4   0.5   0.6   0.7
                                   UV absorbance
                                    314

-------
    The organics was obtained through the equation on the relations between TOC
and UV (254 mm) (cf. Fig. 3.2.16).  The UV absorbance needed for the equation
was measured by  the  continuous UV monitor made by Tinsley Co., Ltd,. The
equation is:
         TOC (mg/£) = 25.0 x UV + 3.44
    The UV monitor is designed to measure the absorbance of visible rays too so as
to eraze the error resulting from the.presence of suspended solids by reducing the
visible  rays absorbance  from that of UV. Except for some special cases, measured
values for discussing the result are average values in every case of run.
b.  Solid Removal
    Fig. 3.2.17  gives the relationship of suspended solids in the influent for the
No. 3  contractor (secondary effluent) and in its effluent.  The SS removal ratio is
independent of suspended solid concentration in the influent by both constant and
varying filtration.  The ratio is about  58% in  constant  filtration against 49% in
varying filtration.  Constant filtration attained a better removal by about 10% than
varying filtration. However, it is a matter for future problem whether this difference
is of any significance,  because  the two methods were tested at  different times —
constant filtration in November and varying filtration in December.
                     Fig. 3.2.17 SS Removal by Carbon Contactor
                               (Influent: Secondary Effluent)
         I
          3 '
         c 2-
        00
        t/1
          1 -
0 Constant (N = 8)
  y = 0.417-X

• Varying (N = 17)
  y = 0.515-X
                                                      No. 3 Contactor
                             3456
                                 SS in influent (mg/C)
                                                               9    10
     The comparison between SS in the effluent from the No. 1 contractor (influent
-  filtered secondary effluent) and that  from the No. 3 contractor shows that the
No. 3 contractor  is a little less efficient than the No. 1 contractor. But the differ-
ence was only 9%. The average SS in the effluent from the No.  1 contractor was
2.0mg/C against 2.2 mg/C in the effluent from the No. 3 contractor (Fig. 3.2.18).
Therefore, it seems that as far  as suspended solid removal no major problem will
arise from omitting filter.
                                      315

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               Fig. 3.2.18 Comparison of SS between No. 1 Contactor Effluent
                         and No. 3 Contactor Effluent
                    2 £2-
                    II
                                    N = 14
                                     y=1.09-X
                                 SS in No. 1 contactor effluent
                          (Influent: Filter effluent of secondary effluent)

      Fig. 3.2.19 shows the relationship of suspended solids in  the influent of the
 No. 5 contractor (tertiary alum precipitated effluent) and in its effluent. When the
 effluent from alum precipitation was treated by the contractor, no difference was
 found with regard to the SS removal between constant and varying filtration with
 about 62% in both methods. In  the  two  months of experiment, the average SS was
 11.8 mg/£ for the influent against 4.5 mg/£ for the effluent.

                 Fig. 3.2.19 SS Removal by Carbon Contactor
                           (Influent: Effluent from Alum Precipitation of
                                    Secondary Effluent)
  12
  10
00
E
y = 0.381-
N = 23
o  Constant
•  Varying
                                    SS in influent fmg/C)
                                        316

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     In most runs on the No. 3 contractor, washing was started before the total head
loss reaching five meters. It was only once that the SS loading was measured  at the
point of the total head loss reaching five meters.  However, it is possible  to estimate
the SS loading of constant filtration through measured values on the rate of the head
loss against the  SS loading on Fig.  3.2.21.  And the value estimated is an average
3,700 g/m2 (2,100 ~  4,600 g/m2) against average SS in the influent being 4.8  mg/£.
                  Fig. 3.2.20 SS Loading of Carbon Contactor
                            (Influent: Effluent from Alum Precipitation of
                                     Secondary Effluent)
        3000
      S  2000
      CO
      c
         1000  -
                                                o  Constant flow
                                                •  Varying flow
                                                No. 5 Contactor
                               6     8    10    12    14
                                   SS in influent (mg/8)
16    18
20
     Fig. 3.2.20 shows the relationship of the SS loading to suspended solids in the
influent at the total  head loss of 5 m in the No. 5 contractor (influent —  tertiary
alum  precipitated  effluent).  The SS loading rises with the increase of suspended
solids in the influent  in constant filtration. The loading of varying filtration is too
limited to give any definite  conclusion.  But the value of varying filtration is esti-
mated to be smaller than in constant filtration.
     Fig. 3.2.21  and  3.2.22 show the SS loading ratio under  lower  total head loss
than  5 m  against  5 m.   Fig. 3.2.21  gives  results of the  No. 3  contractor, while
Fig. 3.2.22 is those of the No. 5 contractor.
                                      317

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                  Fig. 3.2.21 Total Head Loss ~ SS Loading Ratio
                            (Influent: Secondary Effluent)
         100

          90


          80 -|

          70

      Si
      T   60
      CO
      .3
          40

          30 -

          20

          10

           0
                    No. 3 Contactor
              0
 2           3
Total head loss (m)
     In the case of the No. 3 contractor using the secondary effluent as influent, the
SS loading goes up almost linearlly with the increase of the total head loss up to
3 m.  But when the total head loss exceeds 3 m,  the SS loading increasing ratio for
every unit total head loss drops sharply.  About 90% of the SS loading at 5 m of the
total head loss is achieved by 3 m.  This may probably mean  that the  filtration goes
into  the  complete surface filtration at the total head loss of about 3 m  because of
accumurated  suspended solids in the surface area of carbon. But it must be repeated
that  there was only one case of the total head loss in the No. 3 contractor reaching
to 5 m.  Fig. 3.2.21  shows the results of this single  case. More study is needed to
know exactly about whether the downturn in the  SS loading occurs at  the total head
loss of 3  m or whether 90% of the SS loading at the head loss of 5 m is accomplished
already at the point of 3 m.
                                      318

-------
              Fig. 3.2.22 Total Head Loss- SS Loading Ratio
                        (Influent: Effluent from Alum Precipitation of
                                Secondary Effluent)
         100

          90 -

          80 -

          70 -

          60 -

         1 50 -
       •2  40 J
          30 -

          20 -

          10 -

           0
             0
                       • Average

                       No. 5 Contactor
2           3
Total head loss (m)
                                                          4
     Any development  of this kind  did  not happen  in the No. 5 contractor for
 which the effluent from alum precipitation was used as influent. The SS loading of
 the contractor increased in keeping pace with the increase of the total head loss to
 5 m,  indicating the effective use  of the total head loss. This also means that the
 No. 5 contractor has more of the nature of in-depth filtration than the No. 3  con-
 tractor.
 c.   Organic Removal
     Table 3.2.3 shows average of TOC removal  in the two months of experiment.
 TOC  in  the  effluent  from  the No. 1  contractor is 9.8 mg/C against  10.2mg/C in
 the No. 3 contactor effluent.  The difference was 0.4 mg/2, or 4%.  In view of this,
 it could be concluded that there is little need of filter for TOC removal at present.
     Fig. 3.2.23  shows the relationship between C/Co and BV in the contractors
No. 1  and 2.  Fig. 3.2.24 gives the ratio of TOC in the  effluent from the No. 1  con-
tractor to that from the No. 3 contractor.  Judging from Fig. 3.2.23, carbon appears
to be  breaking,  but this must be more precisely examined by future results. And at
least up to Bed Volume (BV) of 5,000, there is no visible change in the ratio of TOC
in the effluent from the No. 1 contractor to that from the No. 3 contractor.
                                     319

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                                  Table 3.2.3 TOC Removal
Contactor No.
Number of Data
Influent to the Pri-
mary Contactor and
its TOC (mg/C)
TOC of Effluent
(mg/C)
TOC Removal
1
2
20
Filter Effluent of
Secondary Effluent
14.1
9.8
30
4.6
67
3
4
20
Secondary Effluent
14.5
10.2
30
5.1
65
5
6
15
Effluent from Alum
Precipitation of
Secondary Effluent
15.0
8.7
42
4.6
69
*   Contactor Nos. 1, 3 and 5 are the primary contactors, and 2,4 and 6 the secondary.

**  To the influent to the primary contactor.



                                   Fig. 3.2.23 BV ~ C/Co
            0.8.
80.6^
H
o
id  0.4
O
            0.2-

                                                    °o
                              0  D
                                        n  °

                                           QQ             D
        Influent: Filter effluent of secondary effluent          a
              O: Effluent from the primary contactor (No. 1 contactor)
              D: Effluent from the secondary contactor (No. 2 contactor)
                           1000
                                       2000          3000
                                               BV
                                                         4000
                                                                      5000
             Fig. 3.2.24 Comparison of TOC between No. 1 Contactor Effluent and
                        No. 3 Contactor Effluent
         „  1.2
         o  1
            0.9-
           0.8
                    N = 22
                    Average = 1.04
                                   _Q	O_
                    Influent
                     No. 1 contactor: Filter effluent of secondary effluent
                     No. 3 contactor: Secondary effluent
                          1000
                                       2000
                                                    3000
                                                                 4000
                                                                                5000
                                               BV
                                           320

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3.2.3   SUMMARY
    Table 3.2.4 gives the summary of the removal of suspended solids by the filter
and the carbon contractor in terms of the SS removal ratio, the SS loading and the
treated volume under specific operating conditions.
    Followings are the findings of this study:

                              Table 3.2.4  Summary

Filter
Carbon
Con-
tactor
Influent
Second-
ary
Effluent
Tertiary
Alum
Precipi-
tated
Effluent

Filtered
Second-
ary
Effluent
Second-
ary
Effluent
Tertiary
Alum
Precipi-
tated
Effluent
Filtra-
tion
Method
Constant
Varying
Constant
Varying
Constant
Varying
Constant
Varying
Constant
Varying

Filtra-
Rate
(m/day)
180
300
420
500
300
420
120
180
300
180

240

Suspended Solid Removal
Removal (%)
2.5
61
*
61
*
61
*
*
SSinlr
5
61
y = o.:
kfluent
7.5
61
87-x-
61 1 61
y = 0.387-x
61 I 61
y = 0.387-x
42 I 48
y = 0.381-x
42 48
*y = 0.381-x
*
62
*
62
*
62
62
#
—
-
58
49
62
62
42 48
y = 0.381-x
55 | 53
y = 0.521-x-
55 | 53
y = 0.521-x
(mg/fi)
10 20
1-0.02
1-0.02
1-0.02
52 57
H.01
52 57
H.01
52 57
H.01
52 50
-0.36
52 50
-0.36
55 1 53 52 50
y = 0.521-x-0.36
55 1 53 52 50
y = 0.521-x-0.36
- 1 -
-
58
« y =
49
» y =
62
62
-
58
0.417
49
0.515
62
0.381
62
0.381


-
•x
• x
62 62
•x
62 62
•x
SS Loading (g/m1 )
SSinI
2.5 5
- 1,700
nfluent
7.5
2,300
(mg/B)
10
-
20

- 1 3,000 1 3,500 1 -
1 3,000 1 3,500 1
|1,700|2,300|
-
—
|3,100|2,800|
- |2,100|2,800| -
490 650
y *
490 650
«« y =
490 650
*» y =
820
66-X +
820
66-x +
820
66-X +
490 650 820
** y = 66>x +


-
-



-
980 |l,600
320
980 |l,600
320
980 ll,600
320
980 |l,600
320


-



-
-
- - -
700 1 1, 200 1 1,700
-
-
2,000

"
-
Filtered Volume (m'/m1)
SS
2.5 5
560
1 980
|980
810
- 1980
- 1980
310 I 240
310 |240
310 |240
310 |240


-
-
n Influent
7.5 1
500 -
770
770 -
640
770
770
210 19
210 19
) 20
-
-
-
-
-
-
0 160
0 160
210 190 160
210 19



-
0 160


-
-
— — — — —
450 |390
-
370 32
-
0
-
    * y: SS in Effluent (mg/B), x: SS in Influent
   ** y: SS Loading,  x:  SS in Influent
a.   Varying and Constant Filtration
1)   When the secondary effluent is used as influent for filter,  the comparison be-
tween varying and constant filtration at the filtration flow rate  of 300, 420 m/day
leads to the following conclusions:  The effluent by varying filtration contain more
of suspended solids by about  1 mg/£ than that by constant filtration.  The SS load-
ing by varying filtration becames lower by 20 ~ 30%.  The lower efficiency of vary-
ing filtration is also observed as to the SS removal ratio in carbon contractors using
the secondary effluent as influent by 10% drop.
                                      321

-------
2)   When the effluent from alum precipitation is used as the influent for filter or
carbon contractor, there is little  difference of the SS removal and the SS loading
between varying and constant filtration in this study.  In carbon contractors, vary-
ing filtration is a little less efficient in terms of the SS loading.
3)   As seen in varying filtration experiments in the filter using the  secondary
effluent as influent,  time  when the total head loss reach to 3 m is limited to the
closing period of influent flow increasing  or to the time of high influent flow.
About 50%  of  the runs it comes  within one hour in the  closing period of effluent
volume increase.
b.   Filtration of the Secondary Effluent by Filter (Constant Filtration)
1)   In the filter media composition used for this experiment, the optimum filtra-
tion  flow rates in terms of the effluent  quality, and the SS loading are 300 ~ 420 m/
day.  This is understood by the fact that the head loss distribution in the filter bed
came very close to that of in-depth filtration.
2)   When the  rates are 300, 420 m/day, and SS in the influent is 5 mg/C, the SS
removal is 61% and the SS  loading is 3,000 g/m2.
3)   Filtration at the rate  of 180 m/day seems to be the surface filtration. The  rate,
when compared  to the higher rates of  300, 420 m/day, provides no difference as far
as the SS removal ratio. But the SS  loading of this rate is about 60% of that of 300,
420 m/day.
4)   The removal of suspended solids by the anthracite  layer cannot be expected
at the rate of 500 m/day.  Most of the SS capture takes place in the sand layer. At
this rate the SS in the effluent is  by about 1 mg/£ greater than at the rates of 300,
420 m/day.  The SS loading is about 60% of the value for the rates of 300, 420 m/
day.
c.   Filtration of Alum Precipitated  Effluent by Filter (Constant Filtration)
1)   In the rates of 120 ~ 300 m/day, there is no difference in the SS removal and
the SS loading.   When the SS in the influent is 5 mg/8,  the SS removal rate is  55%
and the SS loading 650 g/m2
2)   The  SS removal by anthracite could not  be expected.  Most of the SS capture
takes place in the sand layer.  This means that the anthracite in this bed, having the
effective size of 1.62, is large for  the treatment of the effluent from alum precipita-
tion.
d.   Solid Removal by Carbon Contractor
1)   When treated  by the carbon contractors, the filter  effluent  of the  secondary
effluent and the secondary effluent  itself make no great difference in their effluent
quality.  The quality difference is only 9% for suspended solids and 4% for TOC up
to BV 5,000.
2)   When compared to filter filtration of the secondary  effluent, there is no great
difference in the SS removal efficiency. The carbon contractor also is not inferior in
terms of the SS  loading.
3)   When the  effluent  from  alum  precipitation with  SS of 5 mg/£ is  used as
influent,  the SS removal ratio is  55% and the SS loading is 1,200 g/m2  (the  total
head loss-5 m).  When the  total head loss is 3  m,  the SS loading will be 65% of the
                                     322

-------
value at 5 m of the total head loss, or 780 g/m2.
4)  When  compared to filter filtration by using the effluent from alum precipita-
tion as influent, the carbon contractor  is superior both in the SS removal ratio and
the SS loading.
e.  Filtration of Alum Precipitated Effluent and Secondary Effluent
1)  In the case of the filter filtration at the flow rates of 180, 300 m/day, the SS
removal and the SS loading is better in secondary effluent filtration. The SS loading
of the effluent from alum precipitation was about 30% of that of the  secondary
effluent.
2)  In the case of the carbon contactor, the SS removal rate of the effluent from
alum precipitation was better by 3% but its SS loading was smaller than that of the
secondary effluent.
f.   Future Studies to be Conducted
1)  Varying  filtration experiments by changing the filtration rate gradient or by
changing the ratio of the maximum flow rate to the minimum flow rate.
2)   Dual or multi media filtration of the effluent from alum precipitation by using
anthracite with the effective size smaller than 1.62 mm.
3)  To compare  constant and varying filtration by using  the same filter to verify
the results above.  The experiment is now in progress.
4)  To  examine  the carbon  contractor filtration including  the aspect  of  carbon
regeneration.  Up to now it is known  that the treatment  of sewage including sus-
pended solids by the carbon contractor produces no major problem with regard  to
SS and TOC in the effluent. Also needed is to know the performance of the  carbon
contractor  in  treating  the influent  of  high SS.  The average SS in  the  secondary
effluent used so far is low at 4.5 mg/C.
5)  To  check  whether there is  a  drop in the absorption speed by using coarse
carbon, which have proved to be efficient for the removal of suspended solids.
                                     323

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     CHAPTER  4.  EXPERIMENTAL STUDY ON REGENERATION OF
                   GRANULAR ACTIVATED CARBON
Introduction	  325
4.1   Method in the Experiments 	  325
  4.1.1   Granular Activated Carbon used for Experiments  	  325
  4.1.2   Facilities used in Experiments  	  325
  4.1.3   Items Measured  	  326
  4.1.4   Regenerating Conditions  	  327
4.2   Results of Experiments 	  328
  4.2.1   Recovery Rate with Regeneration 	  328
  4.2.2   Physical Characteristics Change of Granular Activated Carbon	  328
  4.2.3   Change of General Characteristics 	  332
  4.2.4   Adsorption Characteristics of Organic Matter in Water	  335
  4.2.5   Decline of Various Characteristics of Activated Carbon	  335
  4.2.6   Correlation between Each Characteristics of Activated Carbon 	  335
  4.2.7   Parameter as a Base for Calculation of Regenerating Cost  	  338
  4.2.8   Others  	  339
4.3   Summary	  344
Acknowledgement	  344
                                   324

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4.   EXPERIMENTAL STUDY ON REGENERATION OF GRANULAR
    ACTIVATED CARBON
INTRODUCTION
     In wastewater treatment,  particularly in advanced wastewater treatment, it
increases  such  a  case that granular activated carbon is used as a means of removal
of soluble organic substances.
     The  unit cost of granular  activated  carbon  is extremely expensive because a
good quality of bituminous coal as its raw material is difficult to obtain in Japan
and the product yield from  such raw material is very small.  These are the principal
defect  of granular activated carbon  when we used it for wastewater treatment.
Consequently if spent carbon can simply be regenerated at the inexpensive cost, the
utilization of granular activated carbon to wastewater treatment will be increased.
     The  regeneration of granular activated carbon is  normally carried out by the
manufacturers, but in the  case of wastewater treatment which requires  activated
carbon is quantity equivalent to  approximate  1/50 and (approximate 1/100 by
weight) more of wastewater to be treated per day, more regeneration on site is
required as the scale of wastewater treatment becomes larger.
     The  following are the results of our experiments we have conducted four items
on the activated  carbon used in advanced wastewater treatment of the Kyoto pilot
plant by a multiple hearth regeneration furnace.
4.1    METHOD  IN THE EXPERIMENTS
4.1.1   GRANULAR  ACTIVATED CARBON USED FOR  EXPERIMENTS
     The  brands and particle sizes of activated carbon used for our experiments are
shown  in the Table 4.1  and  these types of activated carbon have been used for the
adsorption of rapidly filtered secondary effluent in the Kyoto pilot plant.  In our
adsorption experiments, no  fresh carbon has been added  since we intended  to
observe the changing characteristics of the original carbon with repeat of regener-
ation.  The approximate figures of adsorbed of COD^n  obtained from the result of
adsorption experiment is also shown in Table 4.1.  The CODMn removal in treatment
just before regeneration was approximately 30% in each case.
4.1.2  FACILITIES USED  IN  EXPERIMENTS
     The  facilities used for  our  experiments comprised a regeneration  furnace, an
equipment for  feeding and collecting carbon, an equipment for treating exhaust gas
and a steam  generator.  A  general flow  is as  shown in Fig. 4.1.  The regeneration
furnace is a  vertical  type  six stage hearth furnace having the inside diameter of
750 mm and 1,500 mm of the height which is equipped with eight gas burners. The
arms of the furnace can be rotated within the range of 0.23 to 2.3 rpm by a 0.4 kW
driving motor.
                                    325

-------
                Table 4.1 Carbon Used in Experiment and Adsorbed CODMn
Number of Reactor
1
2
3
4
5
6
Name and Size
Name
Particle Size (Mesh)
Calgon, SGL
8x30
Calgon, CAL
12x40
Takeda, Shirasagi
8x30
Adsorbed CODMn (CODMn kg/kg A.C.)
1st
2nd
3rd
4th
Mean
0.118
0.150
0.132
0.165
0.141
0.074
0.067
0.047
0.067
0.064
0.160
0.170
0.160
0.202
0.189
0.088
0.080
0.061
0.079
0.077
0.121
0.155
0.086
0.125
0.122
0.085
0.057
0.048
0.072
0.066
                    Fig. 4.1  Flow Diagram of the Regeneration System








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4.1.3   ITEMS  MEASURED
     The items indicating the characteristics of granular activated carbon that meas-
ured  in this experiment are; physical characteristics (mean  particle size,  hardness
number,  ignition  residue,  specific surface  area, mean  micropore size, volume of
micropore, micropore  distribution),  general adsorption  characteristics (methylen
blue decolorizing capacity, iodine adsorption capacity, molasses decolorizing capaci-
ty, phenole value,  ABS value), adsorption capacity of  organic substances in water
and  weight ratio of  adsorbed  matter to fresh carbon.*   Measuring has been imple-

*:  Weight ratio of adsorbed matter to fresh carbon can be obtained by the following; a 100 kg of dried sample
   of spent carbon will be heated for 90 minuts in an electrical furnace, the temperature of which was controll-
   ed to 900°C in N2 gas flow, and the decreasing of weight are measured, then the weight ratio will be obtained
   according to the following formula;
        Weight Ratio of Adsorbed Matter to Fresh Carbon =  Pleased Weight of Carbon (g)
                                                 Weight of Recovered Carbon (g)
                                         326

-------
mented  in accordance  with JIS standards and  Japan Water  Works Association
(AWWA) Standards as far as practicable, but the details of the method have been
omitted because it was described in the previous report.
4.1.4   REGENERATING CONDITIONS
    Regenerating efficiency of granular activated carbon in  the regeneration fur-
nace will be governed by the following factors;
(1) Temperature and its distribution in furnace
(2) Detention time of activated carbon in furnace
(3) Atmosphere in furnace
(4) Feed rate of steam for reactivation and its feeding position
(5) Loading rate of carbon
    In  our experiments, the furnace temperature has been kept in 930 to 940° C at
a maximum.  Each stage  of 4th,  5th  and 6th hearth for activating has been so set as
to be able to maintain nearly the same temperature. The detention time of activated
carbon  in the furnace has been  set for 30 min. regardless of the type and loading
quantity of carbon.  Atmosphere in the furnace has been so controlled that O2 for
each stage should be kept below 0.1% to avoid the burning-off of carbon due to the
entrance of air.
    The activating temperature has been changed based on  the type of activated
carbon and apparent density  which show the result for any change of loading quanti-
ty and can be measured easily.  One  third  of the steam has been fed  to the stage 4
and the remainder to the stage 6.
     The loading  rate  of activated carbon has been set at from 11  to 15 kg/m2 of
furnace floor/hr on the basis  of dry spent carbon by weight.
     Total feeding  weight or volume and loading quantity/hr in  the regeneration
experiments carried out four times are as shown in Table 4.2.  The activated carbon
        Table 4.2 Feeding Weight and Feeding Rate of Each Carbon in the Experiment
\~ — -_____Reactor
It \xRegeneratiorf^\
Items ^---5_L_ \^
Weight of
Feeded
Activated
Carbon
(DSC kg)

Weight of
Feeded
Activated
Carbon
per Hour
(kg DSC/Hr)
1st
2nd
3rd

4th
Mean
1st
2nd

3rd
4th
Mean

1

836.0
784.9
670.9

618.5
727.6
39.5
34.2

33.5
34.4
35.4

2

836.0
752.3
601.9

546.5
684.2
34.3
32.4

31.7
33.0
32.9

3

696.7
681.5
577.6

596.2
563.0
33.6
36.9

28.1
32.5
32.8

4

727.5
645.6
567.7

550.5
622.8
32.1
31.0

28.8
30.2
30.5

5

809.0
798.0
735.8

733.3
769.0
35.6
38.2

35.0
36.1
36.2

6

835.9
791.7
693.3

686.3
751.8
34.0
36.8

32.8
33.9
34.4
                                     327

-------
withdrawn from the reactor has been put into the hemp sack and dewatered when
the specific gravity was stabilized  in wet condition.  The activated carbon has been
loaded by weighing each sack of carbon.
     In adsorption experiments at the  pilot plant, each of the carbon was divided
and  packed  into two vessels. And  the  vessels  were operated in series.  So, this
regeneration experiment has been implemented by  two vessels in a similar manner.
The first experiment has been carried  out in December, 1974, the second experi-
ment in August, 1975, the  third experiment in  February,  1976 and the fourth
experiment in August, 1976 respectively.
4.2   RESULTS OF EXPERIMENTS
4.2.1  RECOVERY  RATE WITH REGENERATION
     The recovery rate of activated carbon with regeneration can be expressed both
gravimetrically  and  volumetrically.  It  is generally said that  the  reliability of the
former is greater than that  of the latter although the former has problems that we
cannot grasp any change of particle size arising from mechanical and thermal losses
and  that we  cannot distinguish  the influence of  accumulation of inorganic sub-
stances.
     Gravimetric recovery rate (Rw) can be  obtained  from dry weight of spent
carbon (Ws), weight ratio of adsorbed matter to fresh carbon (a) and dry weight  of
regenerated carbon (Wr).
                   Ws
     The volumetric recovery  rate can further be  obtained  1 ) from the height of
packed carbon and cross sectional area of the reactor and 2) from volumetric figures
calculated by dividing carbon weight with apparent density.
     Each recovery  rate obtained  from  this experiment is as  indicated in Table 4. 3.
Each recovery rate  varies  by the  type of carbon and by the frequency of use,  but
was approximately 85% and above.
     The fluctuation of height of packed carbon in reactor and apparent density
(measured by a 100 m£ measuring cylinder) with repeat of regeneration is as shown
in Fig. 4.2.  In Fig. 4.2 and other diagrams, F, S and R on  horizontal  axis  denote
fresh carbon, spent carbon and  regenerated carbon,  respectively.  The numbers
show the frequency of adsorption and regeneration.  From Fig. 4.2, it is noted that
apparent density relatively reduces as the carbon is regenerated repeatedly and that
the height of packed carbon lowers linearly. In accordance with that, carbon weight
of each reactor is reduced to approximate 50% of the original carbon weight only by
four times regeneration although it include a loss in back washing.
4.2.2  PHYSICAL CHARACTERISTICS CHANGE OF GRANULAR
       ACTIVATED CARBON
     Out of  physical characteristics of the activated  carbon. Fig. 4.3  shows  the
change occurring from the repeated regeneration on mean particle size, hardness,
ignition residue, specific surface  area and mean micropore size  of micropore 0 to
300A. From these figures, it can  be seen  that by the repeat of regeneration, mean
particle size and hardness have not been changed very much, but  ignition residue,
                                     328

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                    Table 4.3  Recovery Rates in Regeneration Test (%}
^\~ 	 — _____Reactor
^xRegeneratiorfX.
Items ^— ^ — \
Gravi-
metric
Recovery
Rate
Volu-
metric
Recovery
Rate
1
Volu-
metric
Recovery
Rate
2
1st
2nd
3rd
4th
Mean
1st
2nd
3rd
4th
Mean
1st
2nd
3rd
4th
Mean
1
96.2
91.9
94.7
90.8
93.4
95.6
88.0
90.2
83.8
89.4
99.3
92.7
100.6
93.0
96.4
2
94.0
96.8
93.0
91.9
93.9
94.1
89.6
84.7
80.0
87.1
96.1
94.0
95.7
95.9
95.4
3
102.3
95.1
98.5
99.8
98.9
97.4
90.0
83.2
86.1
89.2
107.7
96.7
105.2
103.0
103.2
4
98.1
105.1
89.7
94.1
96.8
94.1
91.1
86.3
87.1
89.7
98.2
100.0
90.0
94.5
95.7
5
100.2
99.6
87.7
89.6
94.3
95.8
93.4
84.8
87.4
90.4
99.8
98.5
90.8
92.2
95.3
6
97.0
93.8
98.7
95.1
96.2
96.1
91.8
93.4
90.6
93.0
98.5
92.2
101.4
95.2
96.8
    Fig. 4.2  Change of Thickness, Weight and Apparent Density of Carbons with Repeat
             of Regeneration
100 -
                                Note: The numbers in circle show column number ol carbon reactor
          F  IS  1R 2S 2R 3S 3R 4S  4R  F  IS  IR  2S  2R 3S  3R 4S  4R F  IS  1R 2S  2R 3S 3R 4S 4R
                                           329

-------
      Fig. 4.3 Physical Characteristic Change of Granular Activated Carbons with Repeat
             of Regeneration
 1.0 -
            >- SGL, 8 x 30
               I    I
             CAL, 12 x40
             Shirasagi, 8x30
               I    I    I
       F   IS  1R  2S  2R  3S  3R  4S  4R
 (a) Mean particle size
 7.0 -
 %
 6.0 -
 5.0 -
       F   IS  1R  2S
 (c) Ignition residue
                      2R  3S   3R 4S  4R
 20
       F   IS   1R  2S  2R  3S   3R  4S  4R

 (e) Mean pore size of 0~300A
                                             90-
                                             80-
                                             70-
       F   IS  1R  2S  2R  3S  3R  4S  4R
  (b) Hardness value (Remaining rate in shieve)
1000-
m2/g
                                            500-
       F   IS  1R  2S  2R  3S  3R 4S  4R
  (d) Specific surface area
       F   IS   1R   2S   2R  3S  3R 4S  4R

  (0 Converse of phenol value (x 100)
specific  surface  area,  mean micropore size  of micropore 0  to 300A have  been
changed strikingly.  Particularly specific surface area (Fig. 4.3 (d)) has been reduced
to nearly a 50% of the original  area just after the regeneration at the time when the
carbon was  spent.  This  explains well the mutual relationship between adsorption
status and regenerating efficiency.  Further, ignition residue (Fig. 4.3 (c)) and mean
pore  size of micropore 0 to 300A increased little by  little  with the repeat of re-
generation.  The  reduction of  these  values shows the progressing of the deteriora-
tion  of the  activated carbon  considering the reduction  of  adsorption  capacity
                                        330

-------
as will be described later on.  From the investigation of another physical character-
istics of micropore volume, the volume of each micropore size fraction varies with
the repeat of regeneration as shown in Fig. 4.4.  The total volume  of micropore
(Fig. 4.4 (a)) of the spent carbon showed a reduction of its value to 60 ~  70% of
fresh carbon or regenerated carbon.  The difference  in the micropore volume from
300A  to 15 AI (Fig. 4.4 (b))  between fresh carbon  and spent  carbon is  relatively
small,  but the volume increased  gradually  with repeat  of regeneration.   On the
contrary the micropore volume (Fig. 4.4 (f)) up to 12A varied considerably  and the

     Fig. 4.4 Micropore Characteristic Change of Granular Activated Carbons with Repeat
            of Regeneration
                                          0.50 -
                                          cc/g
                                          0.25 -
     0.50
                                                      SGL,8 x30
                                                        I   I   I
                                                      CAL, 12 x40
                                                        I   I   I
                                                      Shirasagi, 8 x 30
                                                        I   I   I    I
            F   IS  IR  2S   2R  3S  3R  4S  4R
         (a) Total volume of 0 ~ 15// micropore
    F   IS  1R  2S  2R  3S  3R  4S  4R
 (b) Volume of 300A ~ 15/u micropore
                                          0.080-
                                           cc/g
                                          0.060-
                                          0.040-
           f   IS  IR  2S  2R  3S  3R 4S  4R
         (cj Volume of 0 — 300A micropore
    F  IS  IR  2S 2R  3S  3R 4S  4R
fd) Volume of 30 ~- 60A micropore
           ¥  IS   IR  2S  2R 3S  3R  4S  4R
        fe) Volume of ]2 "~ 30A micropore
   F   IS  IR  2S   2R  3S  3R 4S 4R
(f) Volume of 0~ 1 2A micropore
value reduced  with  repeat  of regeneration. The difference in the value between
spent and  regenerated carbon  is greater on the volume of micropore size fraction,
but the value has not been noticeably increased  nor decreased very much with repeat
of use and  regeneration.
                                        331

-------
     From the above, we can consider that with repeat of use and regeneration, the
total volume  of micropore has not been changed very much, but micropore volume
of 12A and less has been reduced and in its stead micropore from 300A to 15 ju has
been increased.  This indicates a deterioration of activated carbon.
     Furthermore, in regard to micropore, the distribution has been measured in
each regenerating experiment, but here as an example we have shown a change of
micropore  distribution after the second and the fourth regeneration in comparison
with that of fresh carbon in Fig. 4.5.
     From Fig. 4.5,  it  is noticeably that  micropore reduced  and micropore in-
creased.
4.2.3  CHANGE OF GENERAL CHARACTERISTICS
     As an index of adsorption capacity of the activated  carbon, methylene blue
decolorizing capacity, phenole value and ABS value are generally used. The change
of such an index  with repeat of regeneration in this experiment is as shown in  Fig.
4.6.
     Generally speaking each item has been much changed  with repeat of regenera-
tion  and  the value of spent carbon, fresh  carbon,  and regenerated carbon varied
widely in each case.
     The following is the study on the characteristics of each index;
Methylene Blue Decolorizing Capacity (Fig. 4.6 (a))
     The fluctuation of the  capacity  has sometimes been reduced  to 40 to 50%  and
was gradually reduced with repeat of regeneration.  This index  is proportionate to
the specific surface area of micropore of 15A and more, and is so much alike  the
fluctuation of the specific surface area in (Fig. 4.4 (d)) or micropore volume of 0 to
12A in (Fig. 4.5 (f)).
Iodine Adsorption Capacity (Fig. 4.6 (b))
     The fluctuation of the capacity is such that the capacity  of fresh carbon  has
sometimes been  reduced to 20 to 30%,  but  the value  decreased  with repeat of
regeneration  as shown in Fig. 4.5 (f) and Fig.  4.6 (a).  This index is proportionate
to the specific surface area of micropore of 10A and more.
Molasses Decolorizing Capacity (Fig. 4.6 (c))
     The fluctuation of capacity is such that the capacity of fresh carbon has been
reduced to 25 to  50%, but  the value  shows a reverse trend  of the above  two items
and increases  with repeat of regeneration.
     It is generally said  that this index  is proportionate to the specific surface area
ot micropore of 28A and more, but judging from  the trend on  the  diagram,  the
index is rather alike the change of micropore volume from 300A  to 15 p. as shown in
Fig. 4.4 (b).
Phenole Value (Fig. 4.6 (d))
     This index indicates the required amount of activated carbon to adsorb the unit
amount of phenole.  Consequently, the smaller this value,  the greater the adsorption
capacity.  From Fig.  4.6 (d), the fluctuation of the value  is greater,  but even if the
capacity considerably reduces by the spending, the original capacity can be restored
by regeneration.   The capacity  will not be dropped much even after  the repeated
regeneration.

                                     332

-------
Fig. 4.5  Micropore Distribution Change of Granular Activated Carbons with Repeat
         of Regeneration
„  1.0
 I  0.6
 •5
            \
§•  0.8

E
                                                                	2nd Regenerated carbon
                                                                	4th Regenerated carbon
                                      Diameter of micropore D (A)
                                        (b) CAL 12 x40
                                     Fresh carbon
                                                 I
                                	2nd Regenerated carbon
                                                                	4th Regenerated carbon
                                 logD
                                                             lo4
                                     Diameter of micropore D (A)
                                        (c)  Shirasagi 8 x 30
                                  —  Fresh carbon
                                                 i
                                  — 2nd Regenerated carbon
                                                                   — 4th Regenerated carbon
     Ju
     T
logD
                                    Diameter of micropore D (A)
                                           333

-------
        Fig. 4.6 Adsorption Characteristic Change of Granular Activated Carbons with
               Repeat of Regeneration
                                           0.5 H
          »  SGL,8x30

             CAL, 12x40
                                                     0  Shirasagi, 8 x 30
                                                         I    I    I   I
        F  IS  1R  2S   2R  3S  3R  4S  4R
      (a) Methylen blue decolorizing capacity
      F   IS   1R  2S  2R 3S  3R  4S  4R
    (b) Iodine adsorption capacity
  100 -I
   50 H
100 -\
                                            50 -J
         F   IS   1R  2S  2R 3S  3R  4S  4R
      (c) Molasses decolorizing capacity
      F   IS   1R  2S  2R 3S  3R  4S  4R
    (d) Phenole value
  200 -\
  ;00 -\
300 H
                                           200 H
                                           100 H
         F   IS  1R  2S  2R  3S  3R  4S  4R
      (e) ABS value
      F   IS   1R  2S  2R 3S  3R  4S  4R
    (0 Converse of ABS value (x 100)
ABS Value (Fig. 4.6 (e))
     This  value  is  an  index for the  amount of activated  carbon required  for the
removal of the required ABS as in  the case of phenole value. The fluctuating status
is therefore much  alike that shown in Fig. 4.6  (d). As it was difficult to compare it
directly with physical  characteristics, we took  the converses in consideration of the
meaning of the index and obtained the result as shown in  Fig. 4.6 (f). From this dia-
gram,  it is found  that the  converses of ABS  value  fluctuates quite alike  specific
surface area, micropore  volume of  12A  and  more, methylene  blue decolorizing
capacity and iodine adsorption capacity
                                         334

-------
4.2.4   ADSORPTION CHARACTERISTICS OF ORGANIC MATTER IN WATER
    The major objective of wastewater treatment by activated carbon is to remove
organic matter in the wastewater. In order to study the organic substances adsorp-
tion characteristics of activated carbon which is used for advanced wastewater treat-
ment, it is considered important  to measure the adsorption capacity of the carbon
for same kind of organic substances as contained in wastewater. In this experiment,
therefore, an experiment on isothermal adsorption has been carried out with TOC as
an index for organic matter by using secondary effluent sampled from a pilot plant.
    We have consolidated the data  according to Freundrich equation which was
obtained from the experiments, but due to insufficient data for each experiment and
unstable property of secondary effluent taken for sample, we could not grasp a clear
change of adsorption characteristics  for organic  substances with repeate of regener-
ation.
     In  order to analyze the adsorption  characteristics of activated carbon against
organic  substances in wastewater, it is difficult  to use  the  Freundrich equation
because the  concentration of the substances contained in secondary effluent is very
low and varied.  It is  therefore felt necessary first to identify and  measure  the
organic substances in secondary effluent to be treated and secondly to pick up some
predominant organic substances  and finally  to study the adsorption characteristics
with those pure substances.
4.2.5  DECLINE OF VARIOUS CHARACTERISTICS OF ACTIVATED
       CARBON
     Various characteristics of activated carbon  change little by little with repeat of
use and regeneration, but will not be improved to the level of fresh carbon by re-
generation. This is clearly understood from Fig. 4.3 and Fig. 4.6.
     Now on the assumption that some value of characteristics will be increased A
fold by every  regeneration, the value of characteristics after regeneration n times,
which is expressed in Pn, will be;
         Pn = Po • An          Log Pn = n log A + log Po
         where Po = Characteristics Value of Fresh Carbon
     Here from the  various characteristics values of fresh, spent and regenerated
carbon obtained from the four times regeneration, we have gotten  the values of A
and Po by a minimum involution on the  items which are likely to fit to the above
equation and have gotten the result  as shown in Table 4.4 (a). In the Table, r is a
coefficient  of correlation expressed in logarithms. Table 4.4 (b) indicates all C
values taken from Table  4.4 (a).   The degree  of decline depend  on the type  of
carbon.   The degree of decline  of  various  characteristics are lower than that  of
gravimetric recovery rate.
4.2.6   CORRELATION  BETWEEN  EACH  CHARACTERISTIC  OF
       ACTIVATED CARBON
     As mentioned earlier in 4.2.3, there  exists  a greater correlation between physi-
cal characteristics and  general  adsorption capacity  of  activated carbons.  For
instance, specific surface area in Fig. 4.3 (d) and methylene blue decolorizing capa-
city in Fig. 4.6  (a) shows nearly the same fluctuation.   We have then studied about
correlation between various physical  characteristics and general adsorption capacity

                                    335

-------
                    Table 4.4 (a) Coefficients which show the Characteristic Change with Repeat of Regeneration

                                                                                         log Pn = n-log A + logP0   A =
= 10a, P0= TOb,C = (
100
^
^^^^^ Reactor
Iteni\ Symbol
Specific Surface
Area m2/g
Mean Pore Size of
0-300A Micropore
Volume of Micropore
0-1 SM cc/g
300A~15^ cc/g
0-300A cc/g
0-12A cc/g
Apparent Density
g/2
Mean Particle Size
mm
Methylene Blue
Decolorizing
Capacity mC/g
Iodine Adsorption
Capacity g/g
Molasses Decolor-
izing Capacity ''',
ABS Value
Converse of ABS
Value
Dry Weight of
Carbon kg
1 ~ 2
a
0.0295
0.0195
O.OI021
0.0367'
-0.01037
-0.04101
-0.0077
-0.02456
-0.0228
-0.0175
0.0114
0.0340
-0.03391
-0.07 106
b
2 980
1.321
0.0976
-0.5209
-0.3008
-0.6971
2.686
0.2154
2.237
-0.02632
1.797
1.6352
0.3642
2.9811
r
0.9221
0.9637
0.6129
0.9347
0.6126
0.9421
0.9318
0.9161
0.9076
0.9582
0.7418
0.8170
0.8169
0.9915
A
0.9343
1.0459
1.0238
1.0882
0.9764
0.9098
0.9824
0.9450
0.9489
0.9605
1.0266
1.0814
0.9248
0.8491
Po
955.0
20.94
0.7987
0.3014
0.5003
0.2008
485.3
1.642
172.6
0.9412
62.69
43.17
2.313
957.4
C
^6.57
4.59
2.38
8.82
A2.36
A9.02
Al.76
AS. 50
*5. 14
A3.95
2.66
8.14
A7.52
A15.09
3 ~4
a
-0.0299
0.0204
0.01332
0.0427'
-0.0105s
-0.0426s
-0.0067
0.0082
-0.0385
-0.0232"
0.0090
0.0317
0.03176
-0.0682s
b
3.004
1.335
-0.0625
-0.4962
-0.2615
-0.7035
2.655
0.0041"
2.314
-0.0005"
1.825
1.594
0.4051
2.9519
r
0.8789
0.9680
0.6578
0.9784
0.5143
0.9501
0.9002
0.4499
0.9762
0.9958
0.7945
0.9061
0.9072
0.9791
A
0.9335
1.0481
1.0311
1.1035
0.9759
0.9065
0.9847
1.0191
0.9152
0.9479
1.0210
1.0757
0.9295
0.8547
Po
1009.3
21.63
0.8660
0.3191
0.5476
0.1979
451.6
1.0096
206.1
0.9988
66.90
39.26
2.541
895.2
C
A6.65
4.81
3.11
10.35
A2.41
A9.35
'4.53
1.91
A8.48
a5. 21
2.10
7.57
A7.05
A14.53
5-6
a
-0.0168
0.0207
0.0195"
0.0423
0.0034"
-0.04376
-0.0110
-0.00332
-0.0188
-0.0158'
0.0137
0.0193
-0.0162
-0.0499"
b
2.959
1.317
-0.1146
-0.5303
-0.3257
-0.6777
2.694
0.2020
2.248
-0.0275
1.803
1.6452
0.3514
2.9723
r
0.6769
0.9960
0.8742
0.9799
0.1987
0.9189
0.9787
0.2225
0.8497
0.9714
0.8745
0.9396
0.8728
0.9922
A
0.9621
1.0488
1.0460
1.1023
1.0080
0.9041
0.9750
0.9924
0.9576
0.9643
1.0320
1.0454
0.9634
0.8914
Po
909.9
20.75
0.7681
0.2949
0.4724
0.2100
494.3
1.592
177.0
0.9386
63.62
44.18
2.246
938.2
C
A3. 79
4.88
4.60
10.23
0.80
A9.59
A2.50
A0.76
A4.24
A3.57
3.20
4.54
A3.66
AlO.86
n = time number of regeneration,
Pn = Value showing characteristic of the activated carbon after n th regeneration
Po = Value showing characteristic of the fresh carbon
A = sign of minus
r = Coefficient of correlation

-------
            Table 4.4 (b) Decline of Granular Activated Carbon Characteristics
                        with Repeat of Regeneration
Items
Name of Carbon
^^
Specific Surface Area
Mean Pore Size of
0-300A Micropore
Volume of Micropore
0~15ju
300A-15M
0-300A
0-12A
Apparent Density
Mean
Particle Size
Methylene Blue Decol-
orizing Capacity
Iodine Adsorption
Capacity
Molasses Decolorizing
Capacity
ABS Value
Converse of ABS
Value
Dry Weighs of Packed
Carbon
SGL, 8x30
0.9343
1.0459
1.0238
1.0882
0.9764
0.9098
0.9824
0.9450
0.9489
0.9605
1.0266
1.0814
0.9248
0.8491
6.57
-4.59
-2.38
-8.82
2.36
9.02
1.76
5.50
5.14
3.95
-2.66
-8.14
7.52
15.09
CAL, 12x40
0.9335
1.0481
1.0311
1.1035
0.9759
0.9065
0.9847
1.0191
0.9152
0.9479
1.0210
1.0757
0.9295
0.8547
6.65
-4.81
-3.11
-10.35
2.41
9.35
1.53
-1.91
8.48
5.21
-2.10
-7.57
7.05
14.53
SHIRASAGI, 8 x 30
0.9621
1.0488
1.0460
1.1023
1.0080
0.9041
0.9750
0.9924
0.9576
0.9643
1.0320
1.0454
0.9634
0.8914
3.79
-4.88
-4.60
-10.23
-0.80
9.59
2.50
0.76
4.24
3.57
-3.20
-4.54
3.66
10.86
     Note:  Left number show recovery rate and right show declining rate (%). The numbers were
           calculated statistically from result of experiments.
as well as correlation among adsorption capacities.
     Assuming that item Y and item X is in the relationship as Y = AX + B, we have
obtained the values of A and B as well as  coefficient of correlation R as shown in
Table 4.5 (a).  Further in order to make it easier to understand, we have expressed
these values in matrix as shown in Table 4.5 (b).  In Table 4.5 (a) and Table 4.5 (b),
coefficient of correlation marked with double circles are 0.95 and above, coefficient
of correlation marked  with  a  single circle 0.85 to 0.95, coefficient of correlation
marked with a triangle 0.70 to 0.85.
     From the Table 4.5 (b), relatively high correlation can be noticed as follows;
(1)  Micropore volume from 0 to 300A vs. specific surface area and total micropore
volume.
(2)  Micropore volume from 30 to 60A vs. total micropore volume from 0 to 15/u.
(3)  Methylene  blue  decolorizing  capacity vs.  specific  surface area, micropore
volume  from 0 to 300A, micropore volume from  12 to 30A and micropore volume
from 0 to 12A.
(4)  Iodine adsorption capacity vs.  specific surface area, micropore  volume from 0
to 12A and methyle blue decolorizing  capacity.
                                      337

-------
(5)  Molasses decolorizing capacity vs. Micropore from 0 to 300A
(6)  The converses of ABS value vs. specific surface area, micropore volume from 0
to 300A, micropore  volume from 0 to 12A, methylene blue decolorizing capacity
and iodine adsorption capacity.
4.2.7  PARAMETER AS A BASE FOR CALCULATION OF REGENERATING
       COST
     The regeneration cost  of  activated  carbon is a very expensive so, as the case
may be, it is advisable to purchase fresh  carbon, but in case of regeneration, it must
be more in-expensive than purchasing fresh  carbon if we can  enhance recovery rate
by reducing the costs for fuel,  for electricity and for labor since we require no raw
materials.  Out of the three costs above, most important one is considered to be fuel
cost so we have prepared Table 4.6 covering unit values of all the relevant items of
fuel costs from  the  data obtained-from this experiment. The moisture of spent
carbon feeded into a regeneration furnace  in this experiment was 40 to 50%, but
from Table 4.6, propane  gas consumption for spent carbon with such water content
was  50 to 55 C/kg  wet weight of feeded  carbon, 87 to 99 £/kg dry weight of feeded
carbon while fuel  oil consumption at after-burning room  for treatment  of exhaust
gas was 0.1 to 0.14 e/kg dry weight of feeded carbon.  Further, the feeding rate of
    Table 4.5 (a) Correlation between Each Characteristic of Granular Activated Carbon
                                                                  Y = AX
                                                                       + B
™=:

A
©
O
O
O
O
©
A
O
O
O
O
A
A
O
O
O
©
©
©
	 — — ___
X
Specific Surface Area
m'/g
Specific Surface Area
m'/g
Specific Surface Area
m'/g
Specific Surface Area
m'/g
Specific Surface Area
m:/g
Volume of Total
,.!'cropure cc/g
Volume of Total
Micropore cc/g
Volume of 300A~15n
Micropore cc/g
Volume of 0-300A
Micropore cc/g
Volume of 0-.100A
Micropore cc/g
Volume of 0-300A
Micropore cc/g
Volume ol .12-30A
Micropore Lc/g
Volume ol I2~30'\
Micropore cc/g
Volume ol I2-30A
Micropore cc/g
Volume of 0-I2A
Micropore cc/g
Volume of l)~ 1 2A
Micropore cc/g
Volume of 0-1 2A
Mkropore cc/g
Mcthylene Blue Decol-
orizing Capacity mS/g
Methylene Blue Decol-
orizing Capacily mC/g
Iodine Adsorption
Capacily g/g
	 Carbon
Y
Volume of Total
Micropore cc/g
Volume of 0-300A
Micropore cc/g
Methylene Blue Decol-
orizing Capacity mC/g
Iodine Adsorption
Capacity g/g
Converse of ABS
Value (%)
Volume of 0-300A
Micropore cc/g
Volume of 30-60A
Micropore cc/g
Molassls Decolorizing
Capacity %
Melhylene Blue Decol-
orizing Capacity mC/g
Molassls Decolorizing
Capacity 7r
Converse of ABS
Value ('/„)
Methylene Blue Decol-
orizing Capacity mC/g
Iodine Adsorption
Capacily g/g
Molassls Decolorizing
Capacity %
Methylene Ulue Decol-
orizing Capacity m2/g
Iodine Adsorption
Capacity g/g
Converse of ABS
Value (%)
Iodine Adsorption
Capacity g/g
Converse of ABS
Value (%)
Converse ot ABS
Value (7)

A
0.0005746
0.0004762
0 1506
0.0004774
0.002861
0.6644
0.06289
121.6
293.2
88.57
5 633
832.8
2.677
216.2
680.6
2.175
12.75
0.002993
001916
6 103
SOL
B
0.3148
007339
27.60
0.4668
-0.4466
-0.08849
0.006752
17.85
13.67
23.05
-0.7365
28.03
0.4635
31.79
38.65
0.4995
-0.2121
0.4026
-0.9927
-3.331

R
0.8285
0.9676
0.9186
0.9484
0.9036
0.9364
0.9596
0.7013
0.8798
0.8794
0.8753
0.8576
0.8983
0.7368
0.9186
0.9565
0.8913
0.9754
0.9923
0.9699

A
0.0006005
0.0004919
0.1646
0.0004848
0.002842
0.6744
0.06782
150.6
301.5
95 00
5.496
835.5
2.488
219 1
788.0
2.336
13 36
0.002829
001644
5.644
CAL
B
0.3652
0.08239
27.13
0.4711
-0.3500
-0.1025
0.005039
7.446
13.77
20.76
-0.7054
26.08
0.4642
30.83
4256
05146
-005296
0.4078
-0.6996
-2.935

R
0.8487
0.9738
0.9200
0.9481
0.9328
0.9447
0.9317
0.7549
0.8510
08485
0.9114
0.8980
0.9358
0.7453
0.9250
0.9596
0.9218
0.9903
0.9657
0.9475

A
0.0005522
0.0004899
0.1634
0.0004969
0.003073
0.6470
0.07311
1686
289.5
110.1
5.679
921.2
2.649
3338
607.5
1.932
11.34
0.003059
0.01817
5.674
Shirasagi
B
0.3706
0.06442
22.99
0.4499
-0.5582
-0.08314
0.002073
2.293
19.37
14.80
-0.7214
21.93
0.4656
1784
54.05
0.5328
-0.03731
0.3775
-0.9035
-2.934

R
0.7608
0.9535
0.9272
0.9009
0.9448
0.9141
0.9771
0.7609
0.8439
0.8834
0.8971
0.8446
0.7762
0.8422
0.9224
0.9373
0.9331
0.9775
0.9845
0.9621
                                      338

-------
     Table 4.5 (b) Correlation between Each Characteristic of Granular Activated Carbon
\
Specific
Surface Area
Volume of Micropore
Total
Micropore
300A-15M
0-300A
30-60A
12-30A
0-12A
Methylene Blue
Decolorizing
Capacity
Iodine
Adsorption
Capacity
Molasses
Decolorizing
Capacity
m'/g
cc/g
cc/g
cc/g
cc/g
cc/g
cc/g



Converse of
ABS Value
90-95
O

-
87-92
0
-
-
89-94
0
96-100
94-97
-
so
ill
_ca O a

-
70-77
A
84-89
O
-
73-85
A
-
-
-

Iodine
Adsorption
Capacity
90-95
O
-
-
-
-
77-94
A
93-96
O
97-100

Methylene Blue
Decolorizing
Capacity
91-93
O
-
-
84-88
O
-
84-90
O
91-93
O

Volume of Micropore
fS
T
o
-
-
-



o
-
-
-
-
-

o
VO
1
O
-
93-98
-
-

0
o
m
O
95-98
91-95
O
-

10 "
— o
I a. a
76-85
A
-

Numbers in the frame show range of
correlation coefficient (x 100).
steam for reactivation of carbon  was 0.7 to 1.0 kg/kg while air blow rate for gas
burning was approximate 21.1 liter per liter of propane gas.
     Mean temperature distribution of atmosphere in furnace during regeneration is
as shown in Fig. 4.7 and  the temperature was controlled satisfactorily.
     The concentration  of CO, CO2 and O2  for atmospheric gas in the lowest stage
which we analyzed is as shown in Table 4.7  and from this data, it is found that the
reductive atmosphere was obtained.
4.2.8  OTHERS
     In  this experiment, component of exhaust gas, concentration of odor sub-
stances, and the fluctuation  of content of inorganic substances in activated carbon
before and after regeneration was measured.
Properties and Component of Exhaust Gas
     Properties  and component  of exhaust gas from regenerating furnace itself,
after-burning  room and  scrubber in regeneration of activated carbon are as shown in
Table 4.8.  From  Table 4.8, it can be  said that the  dusts and odor strength are
removed by  after-burning,  but  sulphurous acid  gas and NOx  rather increase.
Scrubber is effective to remove  dusts and sulphurous acid  gas,  but did not contri-
buted to the removal of NOx.  The increase of odor strength at scrubber was due to
the use of secondary effluent for scrubbing.
                                     339

-------
Concentration of Odor Substances
     In  our second and third  regeneration,  the concentrations of odor substances
and dangerous substances contained in  exhaust gas from regenerating furnace and
after-burning room were measured.  The result is shown in Table 4.9. From Table
4.9,  it can be said that the concentration of odor substances  at the outlet of re-
generation  furnace is considerably high,  but after after-burning, such concentration
was considerably  reduced.  This explains  the favorable  impact of after-burning to
odor substances.
Fluctuation of Inorganic Substances  Content with Repeat of Regeneration
     Inorganic substances contained in  carbon and fresh  carbon before and after
regeneration were measured and the fluctuation of content with repeat  of regener-
ation was studied. Items measured were altogether nine covering calcium, cadmium,
chromium, copper, mercury, magnesium, manganese, lead  and zinc.  The results of
this measurement  are as shown in Table 4.10.  With the exception of Ca, Cd, Mn,
                         Table 4.6 Basic Data on Fuel Cost
\x^~ -^-Jleactpr Number
\\ RegeneratiorT^^-^^
Item ^— 	 ~ 	 ^^^
Consumption Rate
of Propane Gas to
Wet Weight of Feeded
Spent Carbon
(E/kg WSC)
Consumption Rate
of Propane Gas to
Dry Weight of Feeded
Spent Carbon
(2/kg DSC)
Oil Consumption Rate
for After Burning to
Wet Weight of Feeded
Spent Carbon
(B/kgWSC)
Oil Consumption Rate
for After Burning to
Dry Weight of Feeded
Spent Carbon
(t/kgDSC)
Steam Feeding Rate
to Dry Weight of
l-eeded Spent Carbon
(kg/kg DSC)
Air Blowing Rate to
Propane Gas

1st
2nd
3rd
4th
Mean
1st
2nd
3rd
4th
Mean
1st
2nd
3rd
4th
Mean
1st
2nd
3rd
4th
Mean
1st
2nd
3rd
4th
Mean
1st
2nd
3rd
4th
Mean
1
48.3
57.8
49.7
55.5
52.8
80.0
95.2
89.0
96.3
90.1
0.0832
0.144
-
0.121
0.116
0.138
0.237
-
0.209
0.195
0.737
0.535
0.901
0.875
0.762
22.5
20.2
22.7
21.6
21.8
2
47.7
57.6
52.3
53.4
52.8
82.6
101.3
99.0
97.1
95.0
0.107
0.163
0.123
0.133
0.132
0.185
0.287
0.233
0.242
0.237
0.962
1.006
1.013
0.909
0.973
24.6
18.9
21.5
19.6
21.2
3
49.0
54.8
62.3
53.1
54.8
85.2
94.4
117.0
97.9
98.6
0.107
0.145
0.100
0.112
0.116
0.185
0.249
0.189
0.206
0.207
0.919
0.899
1.199
0.926
0.986
23.9
18.4
20.9
21.6
21.1
4
43.4
51.1
54.4
49.6
49.6
78.9
93.4
103.7
100.9
94.2
0.121
0.151
0.148
0.141
0.140
0.220
0.277
0.281
0.272
0.263
0.941
0.919
1.052
0.993
0.976
25.3
19.0
20.8
20.5
21.4
5
44.3
55.2
63.4
62.1
56.3
77.1
93.3
109.1
106.3
96.5
0.0967
0.121
0.0946
0.0971
0.102
0.168
0.204
0.163
0.166
0.175
0.870
0.819
0.826
0.801
0.829
25.1
18.1
20.4
21.0
21.2
6
43.4
55.6
5.1.8
50.7
50.4
75.9
93.9
92.7
93.5
89.0
0.116
0.161
0.120
0.120
0.129
0.202
0.216
0.230
0.221
0.217
0.864
0.823
0.951
0.867
0.876
25.0
17.2
21.7
22.3
21.6
                                      340

-------
                     Fig. 4.7 Distribution of Temperature in Furnace
1000
                                                    2nd Regeneration (Aug. 1975)
1st Regeneration (Dec. 1974)
       T.F    2nd     3rd     4th      5th
                         hearth
         3rd Regeneration (Feb. 1976)
                                            4th Regeneration (Aug. 1976)
                                                              Carbon of
                                                              Column 1
                                                                     Carbon of
                                                                     Column 1
                                                              Carbon of
                                                              Column 3
                                                                     Carbon of
                                                                     Column 4
                                                                              Carbon of
                                                                              Column 6
                                                     Carbon of
                                                     Column 5
      T.F    2nd     3rd    4th     5th     6th
 200
                                          341

-------
                     Table 4.7 Contents of Atmosphere Gas (%)
^^^^^ Item
^^^^_^
Times of Regeneration ~^^_^
1
2
3
4

CO

2.0-3.4
1.9-3.4
1.7-1.9
1.7-1.9

CO2

12.0-12.2
11.9-12.9
11.0-11.8
11.1-11.6

02

0.1 or less
0
0
0
                         Table 4.8 Exhaust Gas Component
Items
Gas Temperature °C
Dry Gas Volume Nm3/H
Moisture V/V %
Dust g/Nm3
Method of Analysis

JIS Z8808
JIS Z8808
JIS Z8808
Dust Tube Method
Qn „„ '• JIS K0103 Solution
SUj PP • Conductivity Method
Mri _ : JISK0104 Chemical
N0 ppm Radiation Method
NOx ppm ' JIS KOI 04
Power of Odor (PO) £u™n™ Method
CO2 V/V % Orsat Method
02 V/V % Orsat Method
CO V/V %
Orsat Method
Outlet of Re-
generation Furnace
1st
240
69
42.4
1.31
3
62
-74
65
-76
11.9
10.9
3.3
-
2nd
240
83
42.8
3.14
<5
66
-70
66
-70
11.9
10.4
3.3
3.3
3rd
266
88
39.4
3.84
<5
-
40
-60
10.4
9.6
0.9
2.9
Outlet of After
Burning Room
1st
620
675
22.5
0.16
235
-240
100
-110
105
-115
2.6
11.4
4.0
-
2nd
650
272
21.6
0.27
140
-170
85
-89
88
-94
1.0
7.6
9.3
0
3rd
643
185
35.9
0.26
350
-400
-
125
-135
0
10.2
6.1
0
Outlet of
Scrubber
1st
40
373
2.4
0.05
6-9
113
-123
118
-128
5.3
8.3
8.6
-
2nd
50
294
12.2*
0.05
<5
107
-111
107
-115
2.3
5.8
12.4
0
3rd
25
229
13.1
0.06
<5
-
125
-130
5.1
9.9
6.2
0.2
and Pb, the content of each substance was greater in spent carbon than regenerated
carbon and also  normally greater  in  primary reactor than in secondary reactor.
This explains  that activated  carbon has adsorbed metals to some extent and has
accumulated part of metals without taking off it in regeneration.  A high concentra-
tion of Ca  was due  to the impact from the regeneration of lime in the regenerating
reactor.
                                     342

-------
 Table 4.9 Concentration of Odor and Dangerous Substances in Exhaust Gas (ppm)
Items
Name
Hyarogen
Cyanide
Carbon
Disulfide
Acetic Acid
Formaldehyde
Acetaldehyde
Methane
Ethane
Ammonia
Tri-methyl
Amine
Hydrogen
Sulfide
Methyl
Mercaptan
Dimethyl
Sulfide
Chemical
Formula
HCN
CS2
CH3COOH
HCHO
CH3 -CHO
CH4
C2H6
NH3
(CH3)3-N
H2S
CH3-SH
(CH3)2-S
Measuring Method
JIS K0109 Pyridine
Pyrazolon Method
E.A. Notification No.9
FPD-GC Method
FID -GC Method
JIS K0102 Acetyleace-
tone Method
FID -GC Method
FID -GC Method
FID-GC Method
JISK0099 Indo
Phenol Test
E.A. Notification No.9
E.A. Notification No.9
E.A. Notification No.9
E.A. Notification No.9
Threshold
Value



1.0
0.21



0.0021
0.005
0.041

Outlet of
Furnace
2nd
4.2
120
280
<0.7
<30
1100
54
990
<0.05
<3
<1
<0.5
3rd
5.2
90
370
0.19
19
1.360
3.5
680
<0.08
780
<2
<0.1
Outlet of After
Burning Room
2nd
<0.08
<0.1
40
<0.5
<30
<10
<10
0.49
<0.05
<0.03
0.002
<0.001
3rd
<0.006
<0.02
<0.2
<0.01
<0.3
35
<0.3
0.25
<0.008
0.15
<0.05
<0.03
   Table 4.10 Change of Inorganic Matter Contents with Repeat of Regeneration
                                                                           Unit: ppm
Car-
bon



S
G
L






C
A
L




S
H
I
R
A
S
A
G
I

^^^^Reactor
Status^\~
of Carbon ^\^
F
IS
1R
2S
2R
3S
3R
4S
4R
F
IS
1R
2S
2R
3S
3R
43
4R
I-
IS
1R
2S
2R
3S
3R
4S
4R
Primary Secondary
Ca
40

825
650
645
1575
1260
1800
2100
59

775
725
755
2115
1880
2560
2240
36

850
655
605
2125
1125
2505
2225
Cd
<0.5

<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5

<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5

<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
Cr
<0.5
-
12
25
10
12.1
6.7
25
15
<0.5

24
40
24
14.6
12.1
28
17
<05
-
12
29
10
11.5
4.8
11
1 1
Cu
0.5

16.5
41.0
31.0
45.7
25.7
49
39
1.5
-
37.5
55.0
34.0
61.7
49.1
70
44
0.5

23
49
22
88.5
17.7
64
37
Hg
(0.1)

0.02
1.47
0.05
0.10
<0.01
0.02
<0.01
(0.11)

0.03
1.50
0.03
0.06
0.01
0.10
<0.01
(009)

0.02
0.92
0.02
0.20
<0.01
0.10
<0.01
Mg
69

131
134
118
194
148
260
244
48

141
139
129
270
244
385
328
67

135
131
119
219
135
309
269
Mn
3
-
82
54.5
62
52.3
87.4
82
105
5

195
73
99
88.4
156.5
140
156
2.5

86
76
72
124.5
105.4
157
192
Pb
<5

<5
<5
<5
<5
<5
<5
<5
5

<5
10
<5
<5
<5
<5
<5
<5

<5
<5
<5
<5
<5
<5
<5
Zn
7

20.5
120
8.5
132
7.5
223
18
2

21.0
137
13.5
156
9.0
284
24
4.5

10.5
126
9
122
7.0
247
26
Ca
40


335
278
855
995
915
1270
59


370
330
1260
950
1235
1200
36


388
273
790
750
1215
1200
Cd
<0.5


<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5


<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5


<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
Cr
<0.5


28
8
9.7
7.3
15
11
<0.5


37
11
12.8
9.1
22
13
<0.5


25
7
11.5
6.1
13
8
Cu
0.5

_
43.0
19.5
37.1
20.0
31
16
1.5


395
14.5
42.8
14 3
34
14
0.5


31.5
10.5
20.7
8.6
30
7
Hg
(0.1)


0.28
0.04
0.13
<0.01
0.04
<0.01
(0.11)


0.15
0.04
0.10
<0.01
0.05

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4.3   SUMMARY
     Repeat of regeneration experiments have been conducted on three types of
activated carbon being used for an advanced wastewater treatment at Kyoto pilot
plant and the following have been confirmed;
(1)  Recovery rate was 90 to 100% gravimetrically but 85 to 95% volumetrically.
(2)  Through  the  repeated regeneration, apparent  density  and micropore volume
was decreased, but mean particle size of micropore from 0 to 300A and micropore
volume  from 300A to  15^ was increased.  The rest of the items have not been
changed so much.
(3)  Out of general adsorption capacity, methylene blue decolorizing capacity and
iodine adsorption capacity were decreased through the repeat of regeneration while
molasses decolorizing capacity was  slightly increased.  Phenole value and ABS value
were not fluctuated so much.
(4)  It was  found  that the following items had extremely high correlation each
     other;
     Micropore volume from 0 to 300A vs.  specific surface area, micropore volume
from 30 to 60A vs. total micropore volume from 0 to 15 M-  Iodine adsorption
capacity vs.  methylene blue decolorizing capacity, the converses of ABS values vs.
methylene blue decolorizing capacity and iodine adsorption capacity.
(5)  Propane gas consumption by dry weight of feeding activated carbon was 87 to
99 C/kg. Fuel  oil consumption for  after-burning was 0.1  to 0.14 C/kg. Steam injec-
tion quantity for reactivation of carbon was 0.7 to 1.0 kg/kg.
(6)  Due  to after-burning, dust contained  and odor strength  of exhaust gas  was
decreased, but SOx and NOx were  increased.  Scrubber was effective for the reduc-
tion of SOx, but not for NOx.
(7)  Activated carbon adsorbes or removes metals in wastewater to some degree.
ACKNOWLEDGEMENT
     The author  thanks Mr. Yoneda and his stuff of sewage Works Bureau of Kyoto
City  for their cooperation in the experimental study.
                                   344

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                 UNITED STATES PAPERS

DEVELOPING PROGRAMS FOR  CONTROL  OF NONPOINT
(DIFFUSE)  SOURCES  OF WATER POLLUTION	  347

   R.S. Burd, Water Division,  Region X, USEPA

HISTORY  OF THE CONSTRUCTION GRANTS PROGRAM	  351

   T.P. O'Farrell, Office of Water Program Operations, OWHM,  USEPA

UTILIZATION OF A FEDERAL ACT  (PL 92-500)  IN COORDINATION
WITH GEORGIA'S WATER QUALITY CONTROL PROGRAM	  367

   J.L. Ledbetter, Environmental Protection Division,
   Georgia Department of Natural Resources

FEDERAL-STATE-REGIONAL DEVELOPMENT OF A WASTEWATER
MANAGEMENT PLAN AND A WATER SUPPLY PLAN	  373

   J.L. Ledbetter & H.F. Rebels, Environmental Protection
   Division,  Georgia Department of Natural Resources

REGIONAL SOLUTIONS TO DOMESTIC WASTEWATER MANAGEMENT	  383

   R.S. Burd, Water Division,  Region X, USEPA

URBAN  RUNOFF POLLUTION CONTROL TECHNOLOGY OVERVIEW	  385

   Dr. C.A. Brunner, R.I. Field, H.E. Masters, A.N. Tafuri,
   Municipal Environmental Research Laboratory,  ORD, USEPA

PLANNED  WASTEWATER REUSE - A LITTLE USED  RESOURCE	  457

   F.M. Middleton, Municipal Environmental Research
   Laboratory, ORD, USEPA

INDUSTRIAL WASTEWATER PRETREATMENT AND JOINT
TREATMENT IN PUBLICALLY-OWNED TREATMENT WORKS	  477

   W.J. Lacy, Office of Research and Development, USEPA

CRITERIA AND ASSESSMENT  OF WASTE TREATABILITY	  501

   Dr. R.L. Bunch, Municipal Environmental Research
   Laboratory, ORD, USEPA

UPDATE OF BIOLOGICAL NITROGEN AND PHOSPHORUS CONTROL	  519

   Dr. R.L. Bunch, Municipal Environmental Research
   Laboratory, ORD, USEPA

RESEARCH AND APPLICATION OF WATER RECLAMATION
TECHNOLOGY IN SOUTHERN CALIFORNIA	  545

   F.D. Dryden & M.W. Selna, Sanitation Districts of
   Los Angeles County
                                  345

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                          DEVELOPING PROGRAMS FOR CONTROL OF
                     NONPOINT (DIFFUSE) SOURCES OF WATER POLLUTION
                                      R. S. Burd
                    U.S.  Environmental Protection Agency,  Region  X
                                    1200 Sixth Avenue
                            Seattle, Washington  98101  USA
                                       ABSTRACT

    Controlling nonpoint sources of pollution will be necessary  in  order  to meet the
goals of the Federal  Water Pollution Act.  The paper describes  the magnitude of the
pollution from these  sources and describes a new approach being tried  to solve the
problem.  It primarily relies on State and local governments prescribing "best management
practices'1 and making important land use decisions.  The program  is highlighted by
active citizen participation and a shift from voluntary compliance to  at. least a semi-
regulatory format.
              INTRODUCTION

    Non-point sources of water pollution,
such as runoff from croplands, urban
stormwater, and strip mining, are becoming
the single most important water quality
problems.  To help solve this pollution
problem the U.S.  Congress placed primary
responsibility on the States and local
units of government.   The wastewater
management planning process being carried
out under Section 208 of the 1972 Federal
Water Pollution Control  Act offers some
good possibilities to control this aspect
of water pollution.

               BACKGROUND

    In the U.S.A. current estimates
indicate that perhaps half our national
water pollution problem may come from
nonpoint (diffuse) sources of pollution.
These sources generally involve runoff,
usually after storms, from man-distrubed
land, streets, parking lots and other sur-
face areas.  The  seriousness of the pro-
blem is highlighted by the fact that it is
predicted the 1983 goals of the Federal
Water Pollution Control  Act—i.e. all waters
being clean enough for fishing and swimming
—will  not be met unless this source of
Pollution is brought  under control.
     Further highlights of  the  problems
associated with nonpoint  source pollution
are:  (1) Two billion  tons  of sediment are
delivered to lakes and streams  annually
from over 400 million  acres  of  croplands,
as well as large amounts  of  nitrogen  from
fertilizers, phosphorus from nonpoint sources,
animal wastes from feedlots, and toxic
pesticides.

      (2) Between 5 and 10  percent  of the
total sedfment load is estimated to come
from the 10 to 12 million acres of  Commer-
cial forest harvested  each year.

      (3) Strip mining, which affects about
350,000 acres annually, results in  the dis-
charge of millions of  tons  of acidity and
sediment.

      (4) Urban sprawl, which consumes
hundreds of square miles  per year,  generates
sediment at an even greater  rate than agri-
cultural activities.

      (5) The runoff of stormwater  in urban
areas accounts for the pollution of waters
with large amounts of  toxic  and oxygen—de-
manding materials.  It also  contains  large
amounts of suspended sediments  and  extreme-
ly high but variable coliform counts.
                                            347

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     As point sources of poTIution--sewage
and industrial wastes discharged  through
pipes—are reduced, the nonpoint  sources
gain in relative importance.  There  hasn't
been a systematic national program for  mon-
itoring nonpoint source pollution and its
water quality impact-but-most everyone
agrees this pollution source is a major
problem.
              NEW APPROACH
     One new and important tool for  control-
ling nonpoint source pollution is Section
208 of the Federal Act. It calls  for State
and regional planning for water quality
management.  Funds to do this planning  are
provided by EPA.  As in other areas, the
Federal Government is providing an incen-
tive and mechanism for local governments
to deal with a growing problem.

     This planning for controlling nonpoint
sources of pollution encourages States  and
local government agencies to prescribe  so-
called best management practices  (BPT). We
define BPT as a practice, or combination
of practices, that is determined  by  a State
or local governmental agency to be the  most
effective and practicable means of prevent-
ing or reducing the amount of pollution
generated by nonpoint sources to  a level
compatible with water quality goals.  The
term practicable includes technological,
economic and political considerations.  BPT's
are determined after assessment of the
problem, examination of alternative  practi-
ces and appropriate public participation.
These practices may vary widely according
to local climate, topography, soils, geolo-
gy, vegetation and other conditions.

     For the most part, best management
practices are known and many are  in  daily
use.  But these techniques are not being
widely applied in many areas where serious
water quality degradation is occurring.

     Studies have demonstrated that  good
conservation practices can reduce sediment
yield anywhere from 50 to 90 percent.   It
has been estimated that if soil conserva-
tion practices were applied to all farm
land, nearly 50 percent of the sediment
loading in streams would be eliminated, in
addition to a reduction in such related
pollutants as nutrients and pesticides.

     Some typical best management practices
we hope will be adopted through the  208
planning process are as follows:
       (1) Contour  farming to  reduce erosion
potential;  (2)  leaving  buffer strips of
trees  and shrubs along  streams to  reduce
soil erosion and to  reduce temperature
increases from  sunshine;  (3)  frequent street
sweeping during dry  periods to prevent
storm water from carrying debris,  oil and
other material  into  storm sewers;  (4) sedi-
ment traps at new  construction sites and at
shopping center locations to  prevent silta-
tion of streams; (5)  grass seeding or other
vegetation planting  to  stabilize areas of
construction activity;  and (6)  use of cul-
verts and other engineering structures to
control water flow and  thereby reduce
erosion.  There are  many  other examples of
practices which can  be  effective.  New
techniques are  continually being developed
which should be put  to  work.   Most import-
ant is that each water  quality management
agency define its  own set of  such practices,
tailored to meet specific local problems
and environmental  conditions.

     Prevention is the  key to  the control of
nonpoint source pollution.  And, in this
regard, intelligent  use of the  land is most
important.  Water  quality is  affected,
often very significantly,  by  land use deci-
sions.  For part of  the prevention answer
therefore we are expecting local governments
to use land zoning to   reduce  runoff by
precluding development  in ground water
recharge areas, flood plains  and ecologi-
cally sensitive areas.  Public  acquisition
of land for preservation  areas  is also
encouraged as is preferential  tax treatment
to retain land  for open space  or agricul-
tual purposes.

              IMPLEMENTATION

     There already exist  many  Federal, State
and local programs that deal with some forms
of nonpoint source pollution.   The Federal
Water Pollution Control Act,  and particu-
larly Section 208, seeks  to significantly
expand on and coordinate  these  programs.
Also, the Act suggests  the programs be de-
veloped and carried  out with  the help of a
major public participation effort.  This
has resulted in each State and local
government doing the nonpoint source control
planning to appoint  advisory  committees to
provide assistance.

     The final  result will be a workable
plan that identifies a  governmental unit
best able to perform  the  necessary tasks.
                                            348

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It will also often contain  regulations and
ordinances controlling septic  tank pollu-
tion; land used for development;  and pre-
scribing best management practices for
agriculture, logging, and overall  con-
struction activity.  By putting  these
measures into the form of regulations and
ordinances, a semi-regulatory  (enforcement)
cast is given to the program.  This is
probably necessary even though nonpoint
pollution will be prevented or eliminated
primarily through education and  voluntary
compliance.

    The program described  will  be continu-
ally evaluated for its effectiveness.  If
an evaluation shows the goals  aren't being
met additional measures, such  as  tougher
best management practices,  will  be adopted.
                                           349

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       THE NONPOINT  SOURCES  PROBLEM
                                                SILVICULTURE
AGRICULTURE
                             Upppif Watershed
                                                  water sources
                                                  forest practices
                                                  grazing
                                              HYDROLOGIC
                                              MODIFICATION
                             (other sources  mining, construction, ground water)
                        TYPICAL POLLUTANTS
         1  Sediment                   6  pestjcjdes
         2  Nu'fi«n»s                   7  Heavy Metals
         3  Temperature                „  Di$so|ved Sa|t$
         4  Dissolved Gases   O2 N2      on   •  u . •  i
         c  _  .              ' "•*      9  Organic Materials
         5  Pathogens
                              350

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                       HISTORY OF THE CONSTRUCTION  GRANTS  PROGRAM

                                    T. P. O'Farrell
                          Office of Water Program Operations
                         U.S. Environmental Protection  Agency
                                Washington, D.C.  20460
                                       ABSTRACT

     The 1976 Needs Survey projected  that  by  the  year 1990,  34% of the United States
population will be served by secondary  treatment  and 55% by  greater than secondary
treatment.  Additional funding over the available $18 billion will be required — $13
billion for secondary, $21 billion for  greater  than secondary, and $18 billion for new
interceptor sewers.  This paper discusses  the types of treatment systems that are being,
or will be, employed in the EPA Construction  Grants Program  and the factors that affect
their selection.  Particular attention  is  given to new technologies.   The grants process,
employing the concept of cost-effectiveness,  is discussed.   In addition to the 1976 Needs
Survey, information for this paper was  gathered by interviews with representatives from
the ten EPA Regional offices and  the  review of  over 1000 projects which employ new
technologies.  The survey showed  the  two key  factors which impacted the implementation of
a new technology in the Construction  Grants Program were its cost-effectiveness and the
level of confidence associated with the use of  the system.
              INTRODUCTION

     The United States Environmental
Protection Agency is primarily  a  regulatory
organization which was established  in
1970.  However, included in  the responsi-
bilities of the USEPA is the management
of a public works program  for the construc-
tion of publicly owned wastewater treatment
plants. With $18 billion  in total  Federal
funding, the Construction  Grants  Program
is one  of the Nation's two largest  public
works programs, second only  to  the  federal
highways program in terms  of size.

     The EPA Construction  Grants  Program
was authorized under the Federal  Water
Pollution Control Act, as  amended in 1972
(Public Law 92-500).  This act  is the
fourth  in a series, the first of  which was
passed  in 1948.  The major public works
program began its effective  life  in 1956
with annual appropriations limited  to $50
million.  Originally, individual  grants
were limited to 30% of the cost and were
not to exceed $250,000. Although  the  funds
were limited, this program did  represent
the beginning of Federal recognition  that
funding aid would be necessary  for  the
construction of municipal wastewater
treatment systems.

     Recognizing the increasing threat  of
water pollution caused by insufficient
wastewater treatment and the lack of
communities to fund auich projects,  the
Congress in 1966 passed a new law (PL 84-
660).  The Federal level of participation
was increased to a range between 40-55%.
Appropriations increased from about $200
million in 1968 to $1 billion in 1971.
Under the grants program authorized by
PL 84-660, nearly 14,000 grants for more
than 5.2 billion Federal dollars were made.

     In the late 60's, water quality
standards, exposure of the public to water
pollution issues and resultant  enforcement
conferences prompted municipalities and
industries to consider action toward
                                           351

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reducing the pollution load in  their dis-
charges.  The greatest input to the improve-
ment of the nation's water came with the
passage of the Federal Water Pollution
Control Act (PL 92-500) in October 1972.
The primary goal of PL 92-500 is to "restore
and maintain the chemical, physical and
biological integrity of the Nation's
waters."

     National effluent limitations were
required for all municipal wastewater treat-
ment plants and were to be implemented in
two increments.  Initially, municipal waste-
water treatment facilities must attain a
minimum of secondary treatment by July 1,
1977.  EPA has defined secondary treatment,
based on a monthly average, as 30 mg/1 of
biochemical oxygen demand and suspended
solids and a pH between 6.0 and 9.0.  In
the second level of treatment, all publicly
owned treatment works must achieve "best
practicable waste treatment technology"
(BPWTT) by July 1, 1983.  Because of budg-
etary constraints, EPA has established
secondary treatment as the minimum criteria
for BPWTT for those plants that are not
required to meet more stringent water
quality standards.  The recently completed
EPA Needs Survey showed that 47% of the
facilities will require a level of treat-
ment greater than secondary effluent.  In
these cases, additional BOD,  suspended
solids, nitrogen and phosphorus removals
may be required.

     In order to attain these goals,
authorization for the Construction Grants
Program was included within PL 92-500.  The
Federal share for the cost of the treatment
systems is 75% of the eligible costs.
Localities and many States share the re-
maining capital costs.   Industrial users
are required to pay the capital costs for
the portion of the treatment  works capacity
they use.   Operation and maintenance costs
are shared by the local users.   Projects
are selected for funding based on the
States'  priority lists.  States are re-
quired to  revise their  lists  annually
based on national and State criteria,
severity of the pollution problem, existing
population and the need to preserve high
quality waters.

     The grants process is divided into
the following three segments:
 Step  1  -  Facility planning.   Cost-
 effective and environmentally sound
 projects are developed through considera-
 tion  of  alternatives for treatment plant
 size,  site,  type of process,  method of
 effluent and sludge disposal,  interceptor
 sewer routing,  etc.  Infiltration/Inflow
 analyses and sewer systems survey require-
 ments must be met; environmental assess-
 ments, public input, and consideration of
 all the  other applicable Federal laws are
 required.

 Step  2  -  Design & Specifications Prep-
 aration.   Preliminary development of a
 proportionate user charge system and
 industrial cost  recovery must  begin.   The
 end product  is a set of  detailed drawings,
 specifications and cost  estimates suitable
 for bidding  and  construction.

 Step  3   -   Construction.   Bids must be
 solicited  and reviewed and contracts
 awarded;  on-site inspection, progress
 payments  and audits are  made according to
 EPA regulations.

     As  of January 1977,  $12.2 billion of
 the authorized $18 billion has been obli-
 gated  to projects.   Projects which have
 received  funding include:  approximately
 4500  Step  1  facilities plans for $350
million,  1200 Step 2 designs for $350  mil-
 lion,  and  2300 Step 3 construction projects
 for $10.5  billion.   As seen, with 5700
 projects yet  to  be funded  for  construction
 and more projects  remaining on State pri-
 ority  lists,  additional  funding will be
necessary.

     The results of  the  1976 Needs Survey
were submitted to  Congress  on February 9,
 1977.   In  order  to serve the sanitary
 sewer and  treatment  needs  of the 1990  pop-
 ulation, EPA has estimated  that approxi-
mately $52 billion will  be  required. EPA
has recommended  to Congress that funds be
 authorized over  a  10 year  period.  The
 cost of  $52  billion for  the construction
 of municipal  wastewater  treatment plants
 can be divided into  $13  billion for sec-
 ondary treatment,  $21 billion  for greater
 than  secondary treatment and $18 billion
 for new  interceptors.  As  ctated earlier,
 47% of the facilities will  require some
 treatment  greater  than secondary.  The
 projected  $21 billion are  for  the cost of
 the total  facility to meet greater than
                                            352

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secondary, not just that portion that  re-
sults in greater than secondary  effluent
(i.e., tertiary treatment).

Technologies in the Construction Grants
 Program

     A review of the present  Construction
Grants projects shows that a  variety of
technologies, both conventional,  new and
innovative, are being planned and construc-
ted to meet the goals of PL 92-500.  The
following is a discussion of  the factors
that affect the selection of  a process,
particularly new processes, the  projected
treatment needs (1976 Needs Survey)  and
the results of a regional survey on  the
types of new systems that are being  incor-
porated in the Construction Grants Program.
The regional survey was in response  to
inquiries on the extent to which new and
innovative technologies are being used in
the Construction Grants Program.   The  gen-
eral belief is that there is  only limited
use of new technology in the  program.

     For purposes of discussion,  technolo-
gies have been divided into two  categories;
conventional and new.  New technologies
have been subdivided into proven and un-
proven.

     Conventional Technologies  - systems
that have been widely employed for the
treatment of municipal wastewaters and
sludges for at least 20 years (trickling
filters, activated sludge, lagoons,  anaer-
obic digestion, vacuum filters,  etc).

     New Technologies

Proven -  systems that have  been evalu-
ated on a full scale in the United States
in the last 10 years (rotating bio-disc,
oxygen activated sludge, air  nitrification,
lime chemical clarification,  activated
carbon, land application, oxidation  dit-
ches, etc.)
Unproven  -  systems that have not been
evaluated on a full scale in  the United
States (sludge pyrolysis, co-pyrolysis,
aquaculture, use of solar energy,  energy
recycling, alternative methods of disin-
fection, etc.)

     In addition, there are a number of
modifications to conventional systems  that
will be considered as new technologies.
The author realizes that systems  such  as
land treatment have been  employed  for many
years in the United States.  However, be-
cause these types of systems have  not been
widely used by sanitary engineers,  they
must overcome the same obstacles that face
new technologies.  For this reason,  these
technologies have been classified  as "new"
in this paper.

Factors that Effect the Process Selection.

     There are two key factors which impact
the implementation of a specific system in
the Construction Grants Program —  cost-
effectiveness and the level of confidence
associated with the system.  Successful
implementation generally  occurs when the
system has been sufficiently developed and
can economically compete  with other  systems
in a cost—effective analysis.

     Section 212 of PL 92-500 requires that
applicants for construction grants  provide
sufficient information to demonstrate that
the proposed system is the most cost-
effective alternative for the degree of
treatment required and disposal of waste
solids.  The cost-effectiveness analysis
is conducted in the Step  1 facilities plan.
The basis for the cost-effectiveness
analysis is a comparison  of the capital
and O&M expenses for the  project over a
twenty year planning period.  All  grantees
are required to consider  land application
and other forms of wastewater reuse  as
part of the cost-effective analysis. The
Step 1 facilities plan, which includes the
cost-effective analysis,  is generally per-
formed by the consulting  engineer  hired by
the grantee, accepted by  the municipality
and approved by the State and EPA  review-
ing officials.

     In order to aid the  consulting  engi-
neer in performing the cost-effective
analysis, EPA has published a series of
documents.  One such publication,  "Alter-
native Waste Management Techniques  for
Best Practicable Waste Treatment"  provides
information on conventional and new
systems for the treatment of wastewater
and handling of residual  sludges.   It
should be emphasized again that EPA does
not dictate what processes should  be used,
only that the selected system must be
cost-effective to meet the effluent  quality
required for the protection of the re-
ceiving stream.  Cost-effectiveness  is
the key element in the selection of the
treatment systems.  Non-monetary factors
                                           353

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(social and environmental) are accounted
for descriptively in the cost-effectiveness
analysis in order to determine their signi-
ficance and impact.  Both monetary and non-
monetary factors are considered in the final
selection of the treatment system in the
cost-effectiveness analysis.

     New technologies must be developed
sufficiently in order that their cost-
effectiveness and reliability can be dem-
onstrated.  For conventional systems, this
type of information and experience is avail-
able to the consulting engineer. In reality,
a new technology system should only be
selected over a conventional system if the
system employing new technology is less
costly and more environmentally acceptable.
The procedure for obtaining the required
information for new systems, particularly
new-unproven systems, includes laboratory
tests, bench tests, pilot plant studies
and full scale performance evaluations.
Full scale evaluation is hampered by the
lack of research and development funds
available for such a study.  The EPA
Construction Grant Regulations in section
35.908 provide that new processes, even
those which have been demonstrated under
less than full scale conditions, may be
utilized in the construction of treatment
plants.  However, as a practical considera-
tion, there may be a reluctance on the part
of the potential designers, users and re-
viewers to utilize new technologies until
confidence is gained for dissemination of
data from successful full scale demonstra-
tions .

     In addition to the difficulties en-
countered by unproven new technologies,
certain constraints exist for the imple-
mentation of new proven technologies that
have been demonstrated on a full scale.
The most obvious constraint is the prefer-
ence for the selection of conventional
processes by grantees and consultants be-
cause of their public acceptance and proven
capability to meet effluent standards at a
known cost. A recent EPA survey of the use
of new technology, which included interviews
with EPA Regional and State officials, has
indicated six major reasons inhibiting the
use of demonstrated new technology at the
municipal level. First, familiarization and
information transfer on demonstrated new
technologies to gain public and consultant's
acceptance, has been either slow or insuf-
ficient. Second, lack of adequate operating
and cost data  for  new technology makes it
difficult  to develop  an adequate cost-
effectiveness  alternatives  comparison with
conventional technology.  Third,  there is
no incentive to  consider and  use (i.e.,
risk) new  technology  if the conventional
technology appears to be adequate. Fourth,
utilizing  ajnew  technology  will  often re-
quire expensive  retraining  of operating
personnel.  Fifth,  many new and  alternative
technologies are simply not cost-effective
and accordingly, cannot be  funded by the
grants program.  And  finally,  EPA and State
resources  to review each facilities plan
have been  insufficient to fully  evaluate
the extent to which alternative  technolo-
gies are considered.

     The degree  of  familiarity that a
State, EPA Regional Office, and most impor-
tant, the  consulting  engineer  has with a
new technology,  usually determines whether
a new technology is selected.  With over
8000 active grant  projects  (approximately
60% include treatment  systems), a massive
information transfer  problem  is created.
A State, Region, or consultant often is
not cognizant or familiar with developments
of new technologies in other areas of the
country.  The problem of  familiarity with
a new technology is more  acute for the
smaller consulting  firms. They are usually
regional, have smaller staffs, and are
involved in a fewer number  of  projects.
Accordingly, smaller  firms  are less likely
to know about or be familiar with demon-
strated new technologies  in other regions
of the country.

     This  lack of  information  can also
produce additional  problems. The consult-
ant or reviewing official may  not be aware
of difficulties  that  others have encoun-
tered with systems  the consultant or re-
viewing official is presently  recommend-
ing, designing,  or  approving.

     An important  constraint  on imple-
mentation of sufficiently developed new
technology is the  preference  for con-
ventional systems by  consultants. The
survey corroborated other findings that
consultants, needing  to "serve"  clients by
ensuring projects  achieve required effluent
levels, will select conventional  technolo-
gies.  The fact  is  that the only product
consultants can  offer is  their reputations.
                                            354

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Another important factor is that  consult-
ants may be able to realize greater profits
by utilizing existing designs for con-
ventional systems as opposed to redesigning
for new technologies.

    The fact that municipalities must bear
the full financial burden of operating and
maintaining treatment plants, as  well as
the 25% local share for capital costs in
most cases, tends to add to the reliance on
conventional technologies.  The survey in-
dicated that many municipalities,  especially
the smaller ones, can only afford low salary
levels for plant operating personnel and low
maintenance costs.  Such a situation implies
low skill level for operating personnel,
which would preclude the effective use of
some new technologies requiring a higher
degree of sophistication to operate. In
addition, municipalities are required to
meet the effluent requirements of their
permit.  The threat of legal action as a
result of a permit violation tends to compel
municipalities to accept conventional
systems.

    Other constraints can be found at the
State and Federal levels. EPA pressure to
obligate Construction Grants funds quickly
has resulted in greater implementation of
conventional systems.  This factor along
with the lack of sufficient personnel at
the State and Federal levels has  encouraged
consultants to recommend conventional
systems which are more common to  the indi-
vidual reviewer.

    Certain States have developed lists of
approved processes and methods.   Other
states do not have such lists, but a pro-
posal for funding of a large sized facility
employing sufficiently demonstrated but new
technologies would run the risk of not being
favorably reviewed for grant funding.

    An important factor which has influ-
enced the utilization of some new technol-
ogies within the grants program has been
the publicity or "salesmanship" which has
been provided with the new system. Processes
which have been developed and marketed by
private industries such as pure oxygen
activated sludge and rotating biological
filters, have received wider acceptance
than systems that required less private
industry input, such as land treatment.
1976 Needs  Survey.

     The  1976 Needs  Survey  provides  infor-
mation on the number and  types  of  treat-
ment systems that will  be enlarged,  up-
graded or constructed to  meet  the  goals of
PL 92-500.  The  Survey  projects the  treat-
ment requirements and shows that by  the
year 1990,  34% of the population will  re-
quire secondary  treatment and  55%  will re-
quire greater than secondary.   Greater
than secondary effluent does not necessarily
mean that tertiary treatment will  be re-
quired, only that an effluent  greater  than
that defined by  EPA  as  secondary effluent
(30 mg/1  of BOD  and  30  mg/1 of  SS) will be
necessary.  Eleven percent  of  the  population
will remain unsewered.

     Table  1 summarizes the types, number
and flows of systems that are projected to
treat wastewater in  the United  States.  The
category  labeled "Other"  includes  systems
which were not specifically labeled  on the
survey form.  These  systems may include
both secondary and tertiary treatment
systems.

     As seen in  Table 1,  the majority  of
the wastewater will  be  treated  by  activated
sludge systems.  For the  three  specific
types of  secondary systems  (activated
sludge, trickling filter  and oxidation
ponds), activated sludge  includes  55%  of
the facilities and nearly 80% of flow.
Compared  to oxidation ponds and activated
sludge, the use  of trickling filters is
expected  to decrease.   Many trickling
filter plants are being abandoned  and  re-
placed by other  forms of  secondary treat-
ment because of  the  concern by  engineers
that trickling filter plants cannot  con-
sistently meet the secondary effluent
requirements.

     The  fact that oxidation ponds are 9%
of the flow and  34%  of  the  facilities  is
understandable since over half  of  the
treatment plants in  the Nation  have  flows
less than 0.1 MGD.

     Tertiary treatment systems  are also
included in Table 1.   As  seen,  filtration
has the highest  planned use.  The use  of
the AWT systems  (lime treatment, break-
point chlorination,  ion exchange) is very
limited.  The number  of land treatment
systems is considerably lower than those
irojected by other data which will be  dis-
cussed later.
                                            355

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     The information on tertiary treatment
can be compared with Needs Survey data on
treatment plants that reported "greater
than secondary required."  The survey
showed that 9036 facilities will require an
effluent quality greater than that defined
by EPA as secondary effluent (30 mg/1 of
BOD and 30 mg/1 of SS).  Assuming 19,000
treatment plants, it can then be projected
that 47% of treatment plants will require
"greater than secondary."  Population
projections show that the 47% facilities
correspond to 55% of the projected sewered
population.  It is important to point out
again that "greater than secondary" does
not necessarily mean that tertiary treatment
will be required.  This fact is shown in
Table 2.  The 9036 facilities that responded
"yes" to the question of "greater than
secondary" were sampled to determine their
projected effluent quality (Table 2).
Effluent quality data from all responding
plants was not provided on the survey forms.
However, if as a minimum, additional BOD
removals were required by all responding
plants, the data in Table 2 would represent
85% of those plants where greater than
secondary would be required.

     While 7704 facilities must provide an
effluent with less than 30 mg/1 of BOD,
only 6271 facilities must do better than
30 mg/1 of suspended solids (SS).  These
results are consistent with many permit
limitations, based on water quality
standards, where BOD requirements are gen-
erally lower than SS requirements. Assuming
that filtration would be required to attain
a BOD of less than 20 mg/1, then the 4927
facilities in Table 2 are consistent with
4993 filtration facilities in Table 1.
Apparently, facilities expect to attain
less than 5 mg/1 of BOD by reducing the
suspended solids to less than 10 mg/1.

     Facilities requiring phosphorus re-
moval are also presented in Table 2.  Phos-
phorus removal was assumed to be required
when the effluent limitation was less than
2 mg/1 of phosphorus.  As seen, only 56
plants require phosphorus concentrations
less than 0.5 mg/1 and 180 plants require
phosphorus concentrations between 0.5 and
0.9 mg/1.  This data is consistent with the
two-stage lime projects (70)  listed in
Table 1, since two-stage lime would gen-
erally be applied when the effluent quality
was less than 0.5 mg/1 of phosphorus.  The
majority of the plants that need phosphorus
removal  (83%)  fall  in  the  1-2 mg/1 range
which can be produced  by chemical addition
to the secondary  system.   Chemical addition
to the secondary  system will also result in
BOD and  SS concentrations  less  than 30 mg/1
At the present time, chemical addition to
primary  or secondary systems is used at
approximately  400 facilities.

     Nitrogen  requirements are shown by
the ammonia and total  nitrogen concentra-
tions in Table 2.   The data show that the
majority of the plants will require ammonia
conversion to nitrate  and not total nitro-
gen removal.  Table 1  reported 653 separate
biological nitrification systems while
Table 2  lists  2666  projects requiring
ammonia  removal.  The  addition of ion ex-
change, breakpoint  chlorination or
projected ammonia stripping cannot approach
the number of systems  reported in Table 2.
It would appear that the majority of the
nitrification systems  are single-stage
systems  such as oxidation ditches or
extended aeration plants.  The need for
high removals of  total nitrogen (less than
5 mg/1)  is small with  approximately 200
facilities.  By comparing these results
with facilities which  must provide an
effluent phosphorus concentration of less
than 1 mg/1 and suspended solids of less
than 5 mg/1, it can be seen that the highly
sophisticated AWT systems are probably
limited  to 200 facilities.  As mentioned
earlier, many  facilities expect to attain
a BOD less than 5 mg/1 by reducing the
suspended solids  to less than 10 mg/1.
However, as seen  in Table 1, the use of
activated carbon  (BOD  less than 5 mg/1) is
projected for  295 facilities.

     Needs Survey information on sludge
processes is presented in Table 3.  As
seen, the category  labeled "other" contains
more projects  than  any other single
process.  It is assumed that most of these
projects include  some  type of land disposal
of sludge.  The increased  emphasis on re-
ducing energy  usage has affected the use
of incineration.  However, the  incinera-
tion industry  has responded by  the develop-
ment of  alternative systems to  decrease
energy consumption, which  will  be dis-
cussed later.

EPA Survey on  New Technologies.

     Congressional  committee hearings  on
science  and  technology raised  questions
concerning  the utilization of  new  tech-
                                            356

-------
nologies in the  EPA Construction Grants
Program.  As a result,  a survey was initia-
ted in November  1976 to determine what new
technologies were being used and what
factors influenced  their implementation.
Each of the ten  EPA Regional Offices was
supplied with forms containing new waste-
water and sludge treatment systems
 (Attachment 1).  Forms  were completed for
projects (completed Step 1, Step 2, and
Step 3) which included  a specified system
listed on the form.  In addition, systems
which were considered new in the opinion of
the EPA official but were not en the list
were included.   EPA headquarters personnel
visited each Regional Office, completed the
forms and discussed the results with the
EPA regional staff.  In addition, EPA head-
quarters staff had  the  opportunity to
interview some State representatives.

     The data collected from the survey
has been summarized in  Tables 4 through 8.
In addition to the  presented information,
the survey found a  number of systems being
employed that are not included in the
tables.  These included, screens to replace
primary settlers, use of solar energy,
digester gas utilization, heat recovery,
automatic computer  control systems, aqua-
culture, electric power generation in a
gravity sewer and alternative disinfection
systems such as  ozone.   Over 1000 projects
were identified  in  the  survey as employing
new technology.  Because of time constraints
and work loads,  not all projects that
included new technologies were reviewed and
summarized.   Emphasis was placed on provid-
ing information  on  different types of
systems and as a result, all projects which
included systems with higher usage were
not reviewed.  This was the case with
systems such as  rotating biological con-
tactors (RBC's)  and oxidation ditches
whose use has been  widespread.

     Systems that are used to achieve
secondary effluent  are  included in Table  3.
Land application, which achieves greater
than secondary effluent was also included
in Table 3.  The data shows a widespread
use of oxygen activated sludge,  RBC's and
oxidation ditches for secondary treatment.

     All of  these types of systems are
marketed by  private firms.  Oxidation dit-
ches and RBC's are  the  two systems whose
use has increased rapidly in the United
States.   A draft report by William F.
Ettlich of Gulp, Wesner  and  Gulp  titled
"A Study of Oxidation  Ditch  Plants  and
Technology" lists  544  installations in the
United States.  Mr.  Ettlich  lists 5 reasons
for the increased  use  of oxidation  ditches.

     1.   Construction costs equal  to  or
less than competitive  treatment processes.
     2.   Plants require a minimum  of
mechanical equipment.
     3.   Plants appear  to perform  reason-
ably well even with  minimum  operator
attention, primarily due to  conservative
design.
     4.   Waste sludge is relatively
nuisance free and  is readily disposed  of
at most plants.
     5.   Plants generally do not generate
odors even under poor  operating conditions.

     RBC's have the  capability to be retro-
fitted into an existing  facility  for up-
grading or enlarging.  These units  also
lend themselves toward modular design.
Pure oxygen activated  sludge systems have
been developed and promoted  by several
large companies.   These  systems have been
marketed based on  retrofitting to increase
capacity or capability of handling  high
organic strength waste.

     The information on  land treatment
systems in Table 3 shows  that far more
land application systems  are being  employed
than is shown in the land treatment data
in Table 1.  Table 1 projects 265 land
treatment systems  by 1990 while Table  3
shows 242 projects at  the completed Step 1,
Step 2 or Step 3 stages.  The data  in
Table 3 was a sampling of regional  projects
and did not include  all  land application
projects.   As seen,  land  application is
used more in the West  where  water supplies
are limited.  Activated  Biological  Filters
were not found in  the  northeast section of
the United States.

     Projects for  the  nitrification of
municipal wastewater are  presented  in
Table 5. As seen,  separate stage  air
systems and RBC's were found to be  the
most widely used.  Although  Table 5 only
lists 11 oxidation ditch  systems  designed
for nitrification, many  oxidation ditch
systems are expected to  produce a nitri-
fied effluent.  The  same  is  true  of many
extended aeration  systems which could  be
listed under "combined air."
                                           357

-------
      Table  6  lists  various  tertiary treat-
ment  systems.  This information is con-
sistent with  the  data  shown in Table 1. As
seen,  filtration  is the  highest used form
of  tertiary treatment.   Microscreens are
also  being  employed to improve effluent
quality in  small  facilities.   The  data  shows
that  the use  of the AWT  systems (lime clari-
fication, NH  stripping, activated carbon,
breakpoint  chlorination  and ion exchange)
has not been widespread.  This data is  also
supported by  the  Needs Survey  Data in Table
1.  The effluent  quality data  in Table  2
shows  that  the need for  the AWT systems
(high  levels  of phosphorus,  SS,  BOD,  and
total  nitrogen) apparently  does not exist.

      These  systems  were  developed  in the
late  bO's and early 70's within the Advanced
Waste  Treatment Research Program.   The  major
objective of  this program was  to develop
treatment processes for maximum removal of
contaminants and  repeated reuse of the
Nation's waters.  The level of treatment
produced by these processes is not necessary
to produce  the effluent  qualities  now re-
quired.  Because of the  additional expense
to build, operate and maintain these types
of systems, the application of these systems
will no doubt remain limited.

     Similar comments can be made  concern-
ing the use of the  independent physical/
chemical systems for wastewater treatment.
Data on these systems is presented in
Table  7.  A number  of factors  can  be
attributed to the limited use  of this type
of treatment.

     1.   Effluent  standards do  not  require
the levels of treatment produced from these
systems.
     2.   Energy usage, because  of  the
recalcination of lime and regeneration  of
activated carbon, is extremely high.
     3.   Systems for nitrogen removal  have
not been demonstrated on a  full  scale.
     4.   Systems are generally not  cost-
effective as compared to land  application
when stringent effluent qualities  are re-
quired .

     The draft EPA  report "Energy  Conser-
vation in Municipal Wastewater  Treatment"
by Gulp, Wesner and Gulp Consulting Engi-
neers, compared the energy usage for  a
conventional treatment system  and  an  IPC
system to produce secondary effluent  at  a
flow of 30 MGD.   The conventional  system
which included activated sludge with
incineration of the waste solids required
31,600 x 10  BTU/yr and 10,665 x 10  KWH/yr
of  total energy.  The IPC system which
included incineration of the chemical
sludge and regeneration of activated
carbon required 275,000 x 10^ BTU/yr and
10,777 x 10  KWH/yr of total energy.  The
escalating costs  of fuel in addition to
the availability,  which must be considered
in  the cost-effective analysis, is a
major factor that  will limit the use of
these systems.

      The information on solids processing
projects is included in Table 8.  Compared
to  wastewater treatment systems,  this
information is  relatively small.  Heat
treatment systems  appear to be the most
widely used.   Of  all the systems, including
wastewater treatment,  heat treatment
systems were frequently identified as not
operating properly.

      Concern for  odors and possible health
effects in projects  employing land disposal
of  sludge has led  to the use of chlorine
oxidation and lime stabilization.  The
possible production  of chlorinated hydro-
carbons during  chlorination of organic
sludges has resulted in additional studies
on  this system.   Sludge composting has
become increasingly  popular since compost-
ing raw sludge  without excessive odors has
been demonstrated.

      Energy consumption for solids proces-
'sing has had major impact on systems
presently being considered.   Disposal of
sludge can be energy intensive if fuels
are required.   Sludge  is also the only by-
product which offers the potential for
energy recovery.   Methane gas,  the by-
product of anaerobic digestion,  is being
used for power  generation and direct
coupled combustion engines.   The  energy
report by CWC shows  that methane  gas from
anaerobic digestors  could provide 80% of
the electrical  energy  requirements of the
primary and secondary  treatment systems.

      The volatile  fraction of the waste
solids are a potential source of  energy.
To  reduce fossil  fuel  requirements for
incineration,  increased attention has been
given to filter presses to reduce the
liquid fraction for  incineration without
auxiliary fossil  fuels.  Data from Enviro-
tech Corporation  shows that 22 facilities
                                            358

-------
are being constructed to employ heat re-
cycling to further decrease the water
content prior to incineration.

    Pyrolysis of sewage sludge, because of
its potentially lower fuel inputs and
lower air emissions, is currently being
evaluated to handle the sludge for the New
York/New Jersey area.

    Co-incineration with solid waste is
being used to reduce fossil fuels.  Co-
pyrolysis of sewage sludge and solid waste
is being planned for the Contra Costa waste-
water treatment plant.  Studies have shown
that sufficient energy can be developed for
co-pyrolysis to supply the average demand
for a 30 MGD AWT facility.

                 SUMMARY

    Treatment systems, employing new
technologies and particularly new unproven
technologies, must overcome a series of
obstacles before they are accepted and
utilized by consulting engineers and muni-
cipalities in the Construction Grants
Program.  The use of these systems was
found to be a function of their familiarity
and acceptance by engineers, adequate cost
information, and needs to attain desired
effluent qualities.  Familiarity and
acceptance can be accelerated by an active
sales program by private industry.

    The criticism that new technologies
are not being employed in the Construction
Grants Program is not supported by our
recent surveys.  At the present time,
approximately 2,500 Step 2 and 3 grants
include treatment plants.  The EPA survey
of regional files showed that 697 projects,
or 28%, are using new technologies.  The
percentage is the minimum amount, since
not all new technology projects were
identified in the survey.

    The use of Advanced Waste Treatment
plants to attain very high removals of BOD,
suspended solids, phosphorus and total
nitrogen appears to be limited to 200 of
the 19,000 facilities that require up-
grading, enlarging or construction.
Projected effluent limitations and high
costs of such facilities limit their appli-
cation.

    The amount of land application
projects will be higher than previously
projected.  Limited water  supplies  for
irrigation in various sections  of the
United States will probably have the
greatest impact on the utilization  of this
technology.  The use of  land  treatment  only
in those situations where  very  high
removals of pollutants are required, based
on projected effluent limitations,  would
be limited to approximately 200 facilities.
Our recent survey showed approximately
350 land treatment systems out  of 2,500
treatment plant projects.

     Compared to wastewater treatment
technologies, utilization  of  new sludge
handling and disposal techniques in the
program is lagging.  This  apparent  delay
is a result of the lack  of new  systems  to
be demonstrated or their unsuccessful
demonstration.  Successful demonstration of
energy savings and safe  ultimate disposal
techniques will aid in correcting this
situation.

               REFERENCES

Pound, C.E., Crites, R.W., and  Smith, R.G.,
  "Cost-Effective Comparison  of Land Ap-
  plication and Advanced Wastewater Treat-
  ment," EPA 430/9-75-016; Office of Water
  Program Operations, Environmental Pro-
  tection Agency, November 1975.
                                           359

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                                  TABLE 1

                          1976 NEEDS SURVEY
                       TREATMENT PROCESSES
TYPE OF
SYSTEM
IN USE
NUMBER OF
PROJECTS
UNDER
CONSTRUCTION
NUMBER OF
PROJECTS
PLANNED
NUMBER OF
PROJECTS
ACTIVATED SLUDGE

TRICKLING FILTER

OXIDATION PONDS

LAND TREATMENT

OTHER
NUMBER OF
PROJECTS
3,550
1,727
3,504
51
1,883
NUMBER OF
PROJECTS
559
42
214
10
261
NUMBER OF
PROJECTS
5,847
206
2,527
204
4,001
                                                              TOTAL

                                                        NUMBER OF    FLOW
                                                        PROJECTS  m3/DAY X 1Q3
9,956

1,975

6,245

 265

6,145
100,738

 13,758

 11,507

 1,652

 64,076

-------
                              TABLE 1 (CONTINUED)
                           1976 NEEDS SURVEY
                        TREATMENT PROCESSES
       TYPE OF
       SYSTEM
FILTRATION

ACTIVATED CARBON

TWO STAGE LIME

BIOLOGICAL NITRIFICATION

BIOLOGICAL DENITRIFICATION

ION EXCHANGE

BREAKPOINT CHLORINATION
IN USE
   UNDER
CONSTRUCTION  PLANNED
TOTAL
NUMBER OF
PROJECTS
535
13
15
32
11
0
25
NUMBER OF
PROJECTS
207
13
7
37
7
3

NUMBER OF
PROJECTS
4,251
269
48
584
120
3
82
NUMBER OF
PROJECTS
4,993
295
70
653
138
6
107
FLOW
m3/DAY X
48,383
3,400
1,609
15,193
3,596

628

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                                     TABLE 2
                              1976 NEEDS SURVEY
                  TREATMENT PLANS AND EFFLUENT QUALITY
 BOD EFFLUENT
mg/1  tt OF PLANTS
  SS EFFLUENT
mg/1  tf OF PLANTS
   TOTAL P
mg/1  tt OF PLANTS
   TOTAL N
mg/1  # OF PLANTS
  AMMONIA-N
mg/1  ff OF PLANTS
<5
5-9
10-19
20-29
TOTAL
796
1134
2997
2777
7704
<5
5-9
10-19
20-29

122
1559
2497
2093
6271
<0.5
0.5-0.9
1-2


56
180
1186

1422
<1
1-4.9
5-9.9
10-15

3
198
110
77
388
                                                                    1-1.9
                                                                    2-5
                                                            89
                                                           1098
                                                           1479

                                                           2666

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                          TABLE 3

      SLUDGE PROCESSES  1976 NEEDS SURVEY
                      (Number of Projects)
ANAEROBIC DIGESTION

HEAT TREATMENT

AIR DRYING

DEWATERING

INCINERATION

LANDFILL

LAND SPREADING

OTHERS
                      IN USE
      UNDER
   CONSTRUCTION
PROJECTED
TOTAL
4803
165
5272
1147
1316
1724
584
5939
296
50
286
241
105
127
36
396
3377
124
3910
1701
913
1784
322
4005
8476
339
9468
3089
2334
3635
942
10,340
                          TABLE 4

       BIOLOGICAL SECONDARY TREATMENT
                     (Number of Projects)
 TREATMENT PROCESS


OXYGEN AERATION

RBC

PLASTIC MEDIA

ACT. BIOLOGICAL FILTER

OXIDATION DITCH

LAND APPLICATION*


'ACHIEVES EFFLUENT GREATER THAN SECONDARY
      EPA REGIONS

II  III  IV  V  VI  VII VIII  IX  X   TOTAL
6
6


18
10
8
8


14
1
11
18
5

6
1
16
9
2
2
11
25
10
33
7
2
31
14
5
1
3
3
13
31
5
24
5
5
36
7
2
6

4
10
17
9
4
1
4
15
92
9
12
1
15
22
44
81
121
24
35
176
242
                             363

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                              TABLES
                        NITRIFICATION
                       (Number of Projects)
 TREATMENT PROCESS

SEPARATE STAGE AIR
COMBINED AIR
SEPARATE STAGE O2
COMBINED O2
RBC
DITCH
ACT. BIOLOGICAL FILTER
           EPA REGIONS
    I  II  III  IV  V  VI  VII VIII IX X
2
3


1


5
2
4
1
6
6

11

1

7
4

7 10
3
6 2

5 13
1
2
5 3
1
1 2

6

1
5 10 2
1


1

1 1
TOTAL

 60
 10
 16
  1
 39
 11
  5
                              TABLE 6
                  TERTIARY TREATMENT
                       (Number of Projects)
TREATMENT PROCESS

LIME CLARIFICATION
ALUM CLARIFICATION
FILTRATION
MICROSCREENS
AMMONIA STRIPPING
POWDERED CARBON
GRANULAR CARBON
B.P. CHLORINATION
ION EXCHANGE
         EPA REGIONS
I   II  III IV  V  VI  VII  VIII  IX  X   TOTAL
3

5

1
1
1
1

283

6 17 9
10 2

1
2 8
3
2
1 3

17 14 14
19
1
1
2 1

1
3
2
9



6
1

5
1
14
1
3

4
1
1
5
3
15

1

2


33
6
120
32
6
3
26
6
4
                                364

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                            TABLE 7

         INDEPENDENT  PHYSICAL/CHEMICAL
                        TREATMENT
                      (Number of Projects)
TREATMENT PROCESS


LIME CLARIFICATION

ALUM CLARIFICATION

FILTRATION

GRANULAR CARBON

B.P. CHLORINATION

ION EXCHANGE
      EPA REGIONS

II  III  IV  V  VI  VII  VIII  IX  X
TOTAL
2

2
1


3 1
2
5 1
5 1
2

1 1
1
2 1
2 1

1
3
1
2
2


11
4
13
12
2
1
                           TABLE 8

                  SOLIDS PROCESSING
                      (Number of Projects)
TREATMENT PROCESS


SLUDGE COMPOSTING

CHLORINE OXIDATION

HE AT TREATMENT

LIME STABILIZATION

FILTER PRESS

BELT FILTER

PYROLYSIS

CO-PYROLYSIS

CO-INCINERATION

FERTILIZER
      EPA REGIONS

	V   V  VI VII  VIII IX  X   TOTAL
3
3
4
1
4
1


2

1

4
1
2
1
1
1
2

2
3
5
2
2
1

1
3
2


1 10
1
4
1 2


2
5
1 1 1

22313
1 1 1

1 2
1

2
2411
9
6
35
8
12
9
2
2
11
15
                             365

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                                                                 ATTACHMENT  I
      Project No:
                                                EPA Regions:
      Grant Applicant:_
                                                Name of Preparer:_
      Location:	
      *Check one:
                                                Telephone No:	
                        PL - 92-500 Project Step 2 Grant Awarded  	
                        PL - 92-500 Project Step 3 Grant Awarded  	
                        Old Law Project  	   Step 1 Study Completed
*Date of award (bid)	
*Design average flow (MGD)_
WASTEWATER:
OXYGEN ACTIVATED SLUDGE 	
SPECIFY PROCESS  	
OTHER OXYGEN SYSTEM
                           (specify)
ROTATING BIOLOGICAL CONTACTOR (Disc)
    for BOD REMOVAL _
    for NITRIFICATION
OXIDATION DITCH
ACTIVATED BIO FILTER 	
PLASTIC MEDIA TRICKLING FILTER
LAGOON (POND) UPGRADING 	
    WITH ROCK FILTERS 	
    INTERMITTENT SAND FILTER 	
    SUBMERGED SAND FILTER 	
    OTHER 	 (SPECIFY)	
LAND APPLICATION (TREATMENT) 	
    CROP IRRIGATION
    (or slow rate systems) 	
    RAPID INFILTRATION ___^J~
    OVERLAND FLOW 	
CARBON ADSORPTION 	
    GRANULAR 	
    POWDERED 	
    NEW FILTRATION TECHNIQUES _
    (NOT RAPID SAND FILTERS)
    MULT I OR DUAL MEDIA 	
    SPECIFY
CARBON REGENERATION
LIME TREATMENT
    WITH BIOLOGICAL TREATMENT
    AFTER BIOLOGICAL TREATMENT (tertiary)
    BEFORE NITRIFICATION 	
    PHYSICAL - CHEMICAL
    (no biological treatment) 	
RECARBONATION 	
ION EXCHANGE 	
REVERSE OSMOSIS 	
AMMONIA STRIPPING 	
TUBE SETTLERS 	
MICRO SCREENS 	
NITRIFICATION
    SUSPENDED GROWTH (TANKS) 	
    ATTACHED GROWTH (FILTERS) _
    WITH AIR 	 WITH OXYGEN"
        FLUDIZED BEDS
DENITRIFICATION
           WASTEWATER:
UTILIZATION OF SOLAR ENERGY
(COLLECTORS OR CELLS)
NEW DISINFECTION TECHNOLOGY
    OZONE 	
    ULTRA VIOLET LIGHT 	
    BROMINE CHLORIDE 	
    OTHER 	
        SPECIFY	
DECHLORINATION
                                                         SULFUR DIOXIDE
                                                         OTHER 	
                                                         SPECIFY
                                                     STORM AND COMBINED SEWER
                                                     OVERFLOW TREATMENT 	
                                                         SPECIFY TYPE
                                                     NON-SEWERED TREATMENT
                                                         SPECIFY TYPE
                                                     OTHER INNOVATIVE PROCESSES
                                                         SPECIFY
                                                                SLUDGE:
                                                     CO - INCINERATION 	
                                                     CO - PYROLYSIS 	  PYROLYSIS _
                                                     REGIONAL TREATMENT OF SEPTAGE
                                                     TANK PUMPINGS 	
                                                     SLUDGE COMPOSTING 	
                                                     LIME CONDITIONING 	
                                                     UTILIZATION OF INCINERATOR ASH FOR
                                                     SLUDGE CONDITIONING 	
                                                     CHEMICAL FIXATION  (STABILIZATION)
                                                     OF SLUDGE
                                                         SPECIFY PROCESS
                                                     COMMERCIAL SOIL CONDITIONER/
                                                     FERTILIZER PRODUCTS 	
                                                     DIGESTER GAS DRIVER INTERNAL
                                                     COMBUSTION ENGINES 	
                                                     NEW SLUDGE DEWATERING TECHNIQUE
                                                         HEAT TREATMENT 	
                                                         FILTER PRESS 	
                                                         BELT FILTER 	
                                                         UTILIZATION OF WASTE HEAT _
                                                         SPECIFY
                                                     OTHER INNOVATIVE PROCESSES
                                                         SPECIFY
                                                     COMPUTERIZED PROCESS  CONTROL
    SUSPENDED GROWTH (TANKS) 	
    ATTACHED GROWTH (FILTERS) 	
COMBINED NITRIFICATION-
DENITRIFICATION 	
WASTEWATER REUSE 	
    GROUND WATER RECHARGE 	
    RECREATIONAL REUSE 	
    INDUSTRIAL REUSE 	
    OTHER (SPECIFY)	
DISCUSSION

OTHER INFORMATION AVAILABLE ON THE TECHNOLOGIES  (PROCESSES) CHECKED ABOVE  (VARIATIONS,
PECULIAR CIRCUMSTANCES, ETC )
                                            366

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                 UTILIZATION OF A FEDERAL ACT  (PL 92-500)  IN COORDINATION
                       WITH GEORGIA'S WATER QUALITY CONTROL PROGRAM

                                     J. L.  Ledbetter
                       Director, Environmental Protection Division
                         Georgia Department of Natural Resources
                                     Atlanta,  Georgia
     The 1972 Federal Water Pollution  Control  Act  (PL 92-500)  instantly impacted the
various State water pollution control  programs in  the United States.   At first the
sudden shift of significant statutory  authorities  from a State function to a Federal
function created considerable controversy  and  confusion; however,  as  time passed, the
Federal and State roles were clarified and progress  is being made  toward abatement of
water pollution throughout the Nation.   The State  of Georgia had an active and effective
water pollution control program which  had  been initiated in 1964.   Through the addi-
tional financial support to the State's program provided by Titles I  and II of
PL 92-500, Georgia improved its water  quality  monitoring network and  data processing,
including computer modelling.  In addition, using  the additional legal authorities
established under Titles III and IV  of PL  92-500,  Georgia strengthened its enforce-
ment program through utilization of  the permit program and more stringent levels of
treatment.  By 1977 sufficient progress has been made by Georgia's water quality
control program, in coordination with  PL 92-500, to  enable the State  to meet water
quality standards for almost all rivers, lakes,  and  estuaries.
     The enactment of the 1972 Federal
Water Pollution Control Act  (PL  92-500) by
the U.  S. Congress over a Presidential
veto established a far-reaching  complex
national commitment to eliminate water
pollution problems in the United States.
Instantaneously the water pollution control
program was politicized to an unprecedent-
ed degree.  Prior to PL 92-500,  the indi-
vidual States had used various approaches
to regulate the discharge of pollutants
from industrial and governmental oper-
ations  within their own boundaries;  how-
ever,  this role was superseded by  the
U. S.  Environmental Protection Agency(EPA)
under  PL 92-500.  Simultaneously the Act
implemented another precedent for  the
program - the concept of contractual
obligation and the authorization for EPA
to proceed with an eighteen billion dollar
construction grant program.  This  es-
tablishment of a strong Federal  role and
authorization of the $18 billion for 75
percent construction grants assured a high
level of interest and involvement by pol-
iticians from the Federal, State, and
local government levels.

     No single piece of environmental
legislation in the United  States' history
has provoked as much interest and contro-
versy as PL 92-500.  For the past four
years, the various professional, technical
and trade journals and publications have
been filled with articles  on this subject.
In addition, thousands of  governmental
publications and newspaper articles have
concentrated on the water  pollution con-
trol program.  During this period, numer-
ous conferences and seminars have been
conducted on the subject.  A significant
portion of this attention  to the program
has been in a negative tone with sharp
criticism leveled at the Federal EPA for
its administration of the  program.  Much
of this criticism has been related to the
delays encountered in the  construction
grants program which have delayed the
                                          367

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abatement of pollution from publicly  owned
wastewater treatment works.   Significant
problems have occurred in  the development
and implementation of effluent  limitations
for various industrial dischargers which
could be considered reasonable  and ac-
ceptable to the industrial community.   The
overly optimistic deadlines in  the Act  for
certain accomplishments have  been criti-
cized.

     Section 315 of the Act established
the National Commission on Water Quality
and required a three-year  study.  Fifteen
million dollars were authorized for the
Commission to investigate  and study the
technological aspects as well as the
economic, social, and environmental
effects of the far-reaching objectives  of
the Act.  To a great extent,  the Com-
mission's study and report resulted in
additional controversy for the program.

     Since early 1974, numerous Congres-
sional committees and subcommittees have
conducted investigations and  hearings in
an effort to define problems  related to
this program and to consider  possible
corrective actions.  In late  1976, the  two
houses of Congress failed  to  agree on any
amendments to PL 92-500; therefore, no
significant amendments have been made to
the Act.  The debates and  controversies
surrounding PL 92-500 have continued into
1977.

     A purpose of this paper  is to present
some positive aspects and accomplishments
during this controversial period, specifi-
cally related to the State of Georgia.
Although some of the deadlines and goals
of PL 92-500 have not been met, sub-
stantial progress continues to be made
toward abatement of water pollution.

     To place the impact of PL 92-500 in-
to proper prospective for the Georgia
water quality control program, a few
facts regarding Georgia and the State's
program prior to 1972 must be presented.
Georgia, one of the original  thirteen
colonies, is located on the east coast
in the southeastern portion of the United
States.   With an area of approximately
152,810 square kilometers  (59,000 square
miles),  Georgia is the largest State east
of the Mississippi River.  The State has
a population of about five million
with one  third  of the population located
in the Atlanta  area.   No rivers flow into
Georgia from other States;  however,  numer-
ous streams  originate in the State and flow
in a southerly  direction.   Some of the
rivers flow  into  the  Atlantic Ocean  while
others flow  into  Florida or Alabama  and
thence to the Gulf of Mexico.   Most  of the
State's population live  in  the northern
half of the  State where  the streams  are
small and water quality  problems  are more
severe because  of these  population
pressures.   The State does  receive an
annual rainfall of about 1219  mm  (48
inches).

     Prior to 1964, Georgia had made
limited efforts to control  water  pollution;
however, following enactment of the  1964
Georgia Water Quality Control  Act an
effective program was implemented.   Begin-
ning in early 1965, a technical staff of
engineers, chemists,  and biologists
located and  inventoried  wastewater dis-
chargers in  the State.   Ambient water
quality standards and stream use  classifi-
cations were  established for the  State's
streams in 1966 and 1967.   Wastewater dis-
chargers were placed  on  schedules to
install treatment facilities.   In general,
the local governments and industries were
required to provide 85 percent  reduction
of organic waste  loads as measured by bio-
chemical oxygen demand (BOD) and  to  elimi-
nate the discharge of toxic pollutants.
The schedules established the  end of 1972
as the target date for installation  of
these treatment facilities.

     Less than  10 of  the 440 industries
discharging significant  quantities of
wastewater directly to streams  in the
State failed  to meet  the 1972  deadline.
In general, the installed treatment
facilities provided the  level  of  treat-
ment, five years in advance, which  was
required by July  1, 1977 in PL  92-500.
With local governments,  the progress was
far less successful.   There were  480
publicly owned  wastewater treatment  works
in Georgia which  serve a population  of
2.9 million or  about  60  percent of the
State's population.   These  publicly  owned
wastewater treatment  works  have a designed
capacity of  2.4 x 106 m3/d  (637 mgd) and
are currently treating approximately
1.5 x 106 m  /d  (400 mgd) of wastewater.
                                            368

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Financial and management problems hampered
the efforts to correct water pollution
problems in local governments.  Prior to
the enactment of PL 92-500, there had been
limited financial assistance from the
Federal government.

     In retrospect the enactment of
PL 92-500 was timely for the State of
Georgia.  Industrial dischargers had
installed modern water pollution control
facilities, but local governments were
encountering financial difficulties.
Therefore, the authorization of 75 percent
Federal grants by PL 92-500 would enable
local governments to proceed with programs
to install needed facilities.  Also, the
Georgia program previously had concentrated
on correcting water pollution problems
related to point sources, whereas
PL 92-500 enabled the State to place
emphasis on developing a broader program
which would address all aspects of water
quality management.

     Georgia's water pollution control
program is administered by the Environ-
mental Protection Division of the Depart-
ment of Natural Resources.  Through the
assistance of Governor Jimmy Carter and
the Georgia Legislature, the Georgia Water
Quality Control Act was amended in 1973 to
make it consistent with PL 92-500.

     Utilizing Federal funds provided to
the State under Section 106 of the Federal
Act, Georgia proceeded to modify its water
pollution control program in 1973 in order
to implement the various elements of
PL 92-500.  In accordance with Title III
of the Act significant changes were made
to the State program.  A continuing plan-
ning process for water quality management
was established as required by Section
303(e) of PL 92-500.  The planning process
enabled the State to establish for each
river basin a priority ranking of needed
construction or improvements of waste-
water treatment works.  Also, a total
maximum daily load was determined for
pollutants allowed to be discharged to
each stream segment to assure compliance
with water quality standards.

     An expanded ambient water quality
monitoring and surveillance program was
developed to better identify the quality
of the State's streams.  Considerable
improvements were made  in  the State's
ability to compile  and  evaluate water
quality data.  Through  the use of com-
puters, the information was stored and
evaluated, subsequently much of the infor-
mation was used to  develop computer models
to simulate various stream reaches and the
impact of pollutional loads on the
streams.

      The State's improved water quality
monitoring and data evaluation enabled
various stream reaches  to  be identified as
"water quality limited" or "effluent
limited".  If the pollutional loads from
waste dischargers,  assuming installation
of best practicable treatment (BPT) , along
a particular stream were not predicted to
sufficiently protect water quality to meet
the water quality standards for that
reach, the stream was identified as "water
quality limited" and more  stringent levels
of treatment were required.   If the com-
puter model predicted that installation of
BPT would allow water standards to be met,
the stream was identified  as "effluent
limited" and BPT was the required level of
treatment.  This more scientific approach
to the establishment of required levels of
treatment was an improvement of the State's
program and a positive  impact of PL 92-500.

      As previously discussed,  the pro-
vision of 75 percent Federal construction
grants by PL 92-500 was an essential and
positive element of the Act.   Requirements
for the preparation of  a "facility plan'1
under Section 201 that  would assure proper
identification of needed improvements and
the evaluation of alternatives  for the
provision of the most cost-effective
system to provide these improvements was
a major positive aspect of the  program.
For the first time,  local  governments had
assistance and support  from Federal and
State governmental  agencies in assuring
that their technical consultants developed
a cost-effective solution.   Another major
aspect of the 201 facility plan has been
the requirement for an  evaluation of
inflow-infiltration problems for publicly
owned systems.  These studies have identi-
fied repairs which  can  be  made to the
sewage collection system to reduce flows
which in turn reduce construction, opera-
tion, and maintenance costs for treatment
works.
                                          369

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      The Georgia Environmental Protection
Division has coordinated the State develop-
ed water quality plans under Section 303(e)
of the Act with the 201 facility plans
developed by local governments to identify
the level of treatment required at publicly
owned systems to protect the State's
streams.  Since more than 99 percent of
the sewage from publicly owned systems in
Georgia is presently receiving biological
treatment, the emphasis on the program for
the future is to upgrade and improve exist-
ing systems and install advanced waste
treatment where needed to protect down-
stream water uses.  Downstream water uses
on many of Georgia's relatively small
streams include water supply for other
communities and recreational lakes which
collect and store many of the pollutants
from upstream discharges.  Therefore,
advanced waste treatment systems consist-
ing of 95 percent reduction of BOD,
reduction of phosphorus to 1.0 mg/1,
reduction of ammonia to 2.0 mg/1, the
provision of 6.0 mg/1 of dissolved oxygen
(DO) in the effluent, and disinfection
of the effluent are being required for
several systems in the northern half of
Georgia.  Present studies do not verify
that these levels of treatment will cor-
rect all water quality problems; however,
it is predicted that with these levels of
treatment, present downstream water uses
can continue with reasonable assurance
that the health and welfare of the public
are protected.

      A significant program authorized in
Section 109 of PL 92-500 is one for train-
ing persons in the operation and mainte-
nance of treatment works.  In Georgia, a
full-time training school for operators
has been established in cooperation with
the State Department of Education.  Three
full-time personnel conduct the training
school for operators of treatment works.
A wastewater treatment facility is being
constructed for training purposes at the
school.   Also, an on-the-job training
program has been effectively functioning
for several years.

      One of the major positive elements
of PL 92-500 is the National Pollutant
Discharge Elimination System (NPDES)
permit program established under Section
402 of the Act.  Through the requirements
that each  discharger obtain a permit, the
NPDES permit  program has implemented the
specific effluent  requirements established
for various industrial and publicly owned
systems.   Georgia  was approved by EPA to
administer the NPDES permit program in
early 1974 and has used it effectively to
establish  schedules and conditions for
further improvements needed by certain
dischargers.

      The  NPDES permit program has enabled
several major accomplishments  to  be made.
It has been an effective enforcement tool
and the basis for  substantial  civil penal-
ties throughout the United States.  Imple-
mentation  of  the NPDES permit  program has
brought equity to  the enforcement efforts
across the country.   If a State has been
unwilling  to  administer a strong  effective
program, then EPA  has continued to conduct
the NPDES  permit program.   The maintenance
of a strong,  consistent program has
assured various industries that have in-
stalled modern water pollution control
facilities in Georgia that their  competi-
tors will  do  likewise in other parts of
the country.  This assurance has been
extremely  helpful  to the States with
effective  ongoing  water pollution control
programs.  Another major advantage of this
uniformity is the  fact that an industry
proposing  to  locate a new plant must
install minimum treatment  levels  in any  one
state compared to  another  state.

      Another important and positive
aspect of  the water pollution  control
program under PL 92-500 has been  the
emphasis on public participation  as
required under Section 101(e)  of  the Act.
Understanding and  involvement  of  the Public
are essential to the success of the pro-
gram.  In  order to maintain strong support
and commitment to  the water pollution con-
trol program with  the long-term substantial
levels of  funding  required to  accomplish
the goals  of  the program,  the  citizens of
Georgia and the Nation must understand and
actively advocate  it.

      Georgia, along with  all  the other
States, is now underway with the  develop-
ment of a  statewide plan as required under
Section 208 of the Act.   The 208  plan is
scheduled  to be complete by November 1978.
As required by the Act and rules
                                            370

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promulgated by  EPA,  the 208 plan will
provide Georgia with a comprehensive water
quality management plan for the future.
The 208 plan will place emphasis on non-
point source pollution as well as point
source pollution.  Since a program has
already been developed under Section 303(e)
for point  sources, a major effort of the
208 -program in  Georgia will be to identify
the source and  scope of non-point pol-
lutants.  Then  a program will be developed
to reduce  and control non-point sources in
conjunction with point sources.  It is
anticipated that completion of the 208
plan with  periodic updating will result
in a management tool for the future to
assure adequate protection and management
of the State's  water resources.

      The 1977 status of the water quality
management program in Georgia reflects
efforts under the State's program before
and after  PL 92-500.  Industry in Georgia
will meet  the 1977 requirements of the
Act.  Several publicly owned systems will
not meet the 1977 requirements primarily
because the Federal  construction grant
funds were not  provided as authorized by
PL 92-500.

      Since enactment of PL 92-500, almost
$250 million of Federal construction grant
funds have been obligated for improvements
to publicly owned treatment works in
Georgia.  Many  of these projects are now
complete or under construction.  The
results of this program and the State's
earlier efforts have greatly improved
water quality in the State.  In addition,
the construction grants program has
provided a positive  impact on the economy
by providing jobs and an economic
stimulus during a recession period of the
economy.

      As of 1977, four and one-half years
following  enactment  of PL 92-500, there is
considerably less water pollution in the
State of Georgia.  Of the State's 32,180
kilometers (20,000 miles) of streams, less
than 1609  kilometers (1,000 miles) have
significant water pollution problems that
result in  violation  of water quality
standards.  Perhaps  of more importance is
the fact that to a great extent PL 92-500
has enabled the State to enter the third
century of our Nation  better equipped,
legally and technically, to manage
effectively the water  resources of the
people.
                                           371

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                  FEDERAL-STATE-REGIONAL DEVELOPMENT OF A WASTEWATER
                       MANAGEMENT  PLAN AND A WATER SUPPLY PLAN

                          J. L.  Ledbetter, Division Director
                          H. F.  Reheie, Chief, Water Quality
                           Environmental Protection Division
                       Georgia  Department of Natural Resources
                                    Atlanta, Georgia
      Atlanta,  Georgia  is  a major  population center in the southeastern United States.
Since the region  is located on  one of  the major drainage divides of the United States,
the water resources adjacent  to the region are limited which results in serious water
supply and water  quality control problems.   In order to meet the needs of the future,
the region must plan  and implement a sound water resources management program.  The
Federal government, the State government, and the Atlanta Regional Commission (repre-
senting 46 local  governments) have developed plans to meet the needs of the region to
the year 2000.  Existing systems have  been evaluated and stream studies have been con-
ducted. Twenty-four  biological wastewater treatment works with a total design capacity
of 12.5 m /s  (286 mgd)  and the  impact  of the discharges on the three rivers draining the
region have been  evaluated.   Using the results of these studies and the population
prediction for  the year 2000, it has been determined that water quality standards can
be met and the  necessary water  supply  provided until the year 2000.  In developing the
wastewater management plan, which  required advanced waste treatment for all of the
region, major emphasis  was placed  on protecting downstream water uses, particularly
community water supply  intakes  and recreational lakes.  Conservation of water and water
reuse are additional  considerations that must be fully evaluated in the next few years.
If new technology is  not developed and if water conservation is not practiced, the lack
of water may  well be  the controlling growth factor for the future of the region.
              THE PLANS

      During  the past  three years  compre-
hensive  and cooperative efforts  have  been
made to  develop a wastewater management
plan and a water supply plan for the  met-
ropolitan area of Atlanta, Georgia.   An
in-depth study has been conducted  by  the
U. S.  Environmental Protection Agency
(EPA), the U. S. Army  Corps of Engineers,
the Georgia Environmental Protection  Di-
vision,  and the Atlanta Regional Com-
mission.  The U. S. Environmental  Pro-
tection  Agency and the Corps of  Engineers
represent the Federal  role in the  study.
The Georgia Environmental Protection
Division provides the  State involvement
and the  Atlanta Regional Commission is
the regional participant and represents 46
local governments in the Atlanta area.  The
wastewater and water supply plans1'2 out-
line the various expansions and modifi-
cations required to meet the area's needs
for water supply and sewage treatment from
the mid 1970's to the year 2000.

     Atlanta, Georgia is a major city in
the southeastern United States and serves
as the transportation center of the south-
east.  Many large corporations maintain
regional offices in Atlanta.  Also, most
Federal agencies, including the Environ-
mental Protection Agency, have regional
offices in Atlanta.  Industrial operations
in the area are generally low water users;
                                          373

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consequently, the approximate 7.80 m  /s
(178 mgd) of wastewater from the region's
1.7 million population is primarily domes-
tic sewage.

          THE ATLANTA REGION

      The Atlanta region is located about
335 meters (1100 feet) above sea level.
Although it is not as significant or
spectacular, one of the major drainage
divides of the United States extends  from
a northeasterly direction through the City
to a southwesterly direction.  East of
this divide water eventually flows into
the Atlantic Ocean; whereas, the water
west of this divide flows into the States
of Florida and Alabama and into the Gulf
of Mexico.  The upper portion of the  South
River is formed in Atlanta on the east side
and the Flint River begins on the southern
edge of the City.  The Chattahoochee River
flows to the west of the City.  On all
three of the rivers downstream of the
Atlanta metropolitan area are significant
water users which include recreational
lakes and community water supply system
intakes.

      The Atlanta metropolitan area with
a population of about 1.7 million is one
of the larger population centers in the
United States which is located inland
from the sea and on a relatively small
river.  The Chattahoochee River flow is
regulated by the U. S. Army Corps of
Engineers' Buford Dam - Lake Lanier hydro-
electric operation located some 77.2 km
(48 miles) upstream of Atlanta.  From that
77.2 km (48 miles) reach of the Chattahoo-
chee River four local governments,
including Atlanta, take water to supply
the water systems which collectively
serve one-third of Georgia's population.
This regulated stream, with fluctuating
flows caused by the upstream hydroelectric
operation compounded by significant with-
drawals by water supply intakes, had  flows
in the early 1970's that dropped as low as
17.0 m3/s (600 cfs) further compounding
severe water quality problems downstream
of Atlanta.  The wastewater management
plan and the water supply plan have been
developed to resolve many of the existing
problems and to provide the required
systems to meet the needs of the future.
      The Atlanta region encompasses seven
counties.  These  seven counties  extend
over 5330 square  kilometers  (2058  square
miles).  Although the  1977 population is
approximately  1.7 million, it  is predicted
that by the year  2000  approximately 3.5
million people will  live in  the  Atlanta
region.

     PRESENT STATUS  OF WASTEWATER
         TREATMENT FACILITIES

      All wastewater treatment systems in
the Atlanta Metropolitan Area are modern
facilities.  In the  seven-county metro-
politan area,  a total  of 24 major treat-
ment facilities with design  capacities
ranging f rom 0.044mJ/s to 5.26 m3/s (1.0
mgd to 120 mgd) are  currently in oper-
ation.  Their  total  capacity is  12.5 m /s
(286 mgd) and  collectively they  are treat-
ing a flow of  7.80 m3/s  (178 mgd).

      Although these systems were designed
to achieve secondary biological  treatment,
many of them were designed and con-
structed prior to the  establishment of
regulations by the U.  S.  Environmental
Protection Agency in 1973 which  defined
uniform national  standards for secondary
treatment.  This  definition requires that
all municipal  wastewater treatment facili-
ties achieve at least  85 percent removal
of influent BODc  and suspended solids,  and
produce effluent  quality with BOD^ and
suspended solids  concentrations  not exceed-
ing 30 mg/1 each,  with effluent  pH in the
range of 6-9 standard  units, and fecal
coliform not exceeding a geometric mean of
200/100 ml.  All  of  the  treatment facili-
ties in the Metropolitan Area provide
biological treatment,  but some of these
facilities do  not achieve the secondary
treatment limitations.

      Conditions  which prevent the con-
sistent achievement  of secondary treatment
standards are  inadequate operator training,
staffing, and  maintenance of facilities;
solids handling;  presence of industrial
wastewaters; and  infiltration, inflow, and
combined sewers.

      Most local  government  officials in
Georgia understand the importance of having
sewer systems  and wastewater treatment
                                            374

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facilities in their communities, but many
do not understand the importance of oper-
ation and maintenance for those facilities.
Thus the budgets for plant maintenance  and
salaries for operators are often low.
Hiring and retaining qualified operators,
then training and motivating them  to get
optimum  efficiency from the treatment works
they operate, are significant problems
which are being resolved very slowly.

     Solids handling is a problem which
plagues  a few Metropolitan Atlanta treat-
ment facilities.  Two facilities have an-
aerobic  digesters which ceased to  function
in recent years due to long-term accumula-
tions of grease, grit and heavy metals
from industries, with the only solution to
empty the digesters and place their con-
tents in lagoons or landfills.  In early
1977 the first and third largest treatment
facilities, which incinerate a mixture  of
undigested and digested dewatered  sludge,
had their natural gas fuel supplies inter-
rupted due to a national gas shortage in
critically cold weather.  The partially
treated  sludge had to be landfilled until
natural  gas service was restored.  The
largest  metropolitan facility operated
poorly during most of 1976 since several
of its primary settling tanks were out  of
service  during construction, causing sig-
nificant solids losses.

     Industrial wastes which enter the
sewer systems without adequate pretreat-
ment cause upsets of biological treatment
processes.  All local governments  have  un-
dertaken programs to identify industrial
contributors and determine their waste-
water characteristics.  These programs
will eventually lead to the necessary pre-
treatment or the elimination of incompati-
ble wastes.

     Sewer systems in the suburban areas
surrounding the City of Atlanta are rela-
tively new and generally do not have se-
vere problems with infiltration and in-
flow.  However, most engineering studies
completed recently have shown that prob-
lems with infiltration/inflow exist in
some portions of every sewage treatment
plant service area.  Certain portions of
the City of Atlanta are served by  combined
storm and sanitary sewers, some of which
were built as many as seventy years ago.
There are four combined sewer overflow
points in the South River Basin3.   Federal
construction grants are being  offered  to
assist local governments in  rehabilitating
sewers which have excessive  infiltration
and inflow.  In the South River  Basin,
grants will be made available  to provide
secondary treatment for combined sewer
overflows resulting from rainfalls  of up
to 1.8 cm (0.7 in).

     Table 1 is a compilation  of relevant
information on existing treatment works
with capacities exceeding 0.22 m /s (5
mgd), and Table 2 lists some average
influent and effluent wastewater charac-
teristics for these facilities for  1976.

     WATER QUALITY MANAGEMENT  PLANS

     Section 303(e) of the Federal  Water
Pollution Control Act of 1972  requires all
states to develop comprehensive  water
quality management plans for each major
river basin.  These documents  must  contain
inventories of all point wastewater
sources, assessments of the  effects of
those pollution sources on the quality of
receiving waters, and waste  load allo-
cations for each pollution source.   This
information is then used to  develop
effluent limitations for discharges and  to
establish priorities for pollution  abate-
ment efforts.

     Prior to the passage of Public Law
92-500, the State of Georgia had already
begun the function of water  quality
management planning.  Programs undertaken
by the State began with'documentation of
serious water pollution problems in the
three stream systems receiving the  most
wastewater in the Atlanta Metropolitan
Area:  the Chattahoochee, Flint and  South
Rivers.  Following this documentation,
the State undertook programs to  measure
certain physical, chemical,  and  biological
characteristics of the streams so that
mathematical models for certain  water
quality parameters could be  developed.
Dissolved oxygen depletion was considered
to be the most serious water quality
problem in all three of these  streams.
All three streams had organic  and nitroge-
nous waste loads sufficiently  high  to
cause septic conditions during periods of
warm weather and low stream  flows,  even
with good stream reaeration  character-
istics.
                                          375

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TABLE 1.  SYSTEM DESCRIPTION - MAJOR  TREATMENT WORKS
          ATLANTA, GEORGIA METROPOLITAN  AREA
Facility

Flint River WPCP #1

Flint River WPCP #2

South River WPCP

Intrenchment Creek WPCP

Snapfinger WPCP

Big Creek WPCP

Chattahoochee WPCP

Clayton WPCP

Utoy Creek WPCP

South Cobb WPCP

Camp Creek WPCP
Type of
Treatment
AS
AS & TF
AS & TF
TF
AS & TF
AS
AS
AS
AS
AS
AS
Treatment
mgd
6
9
18
20
22
6
10
120
30
8
15
Capacity
0.26
0.39
0.79
0.88
0.96
0.26
0.44
5.26
1.31
0.35
0.66
Type of
Sewer
System
SEP
SEP
COM
COM
SEP
SEP
SEP
COM
COM
SEP
SEP
Receiving
River
Flint
Flint
South
South
South
Chattahoochee
Chattahoochee
Chattahoochee
Chattahoochee
Chattahoochee
Chattahoochee
ABBREVIATIONS:  WPCP - Water Pollution Control Plant
                AS   - Activated Sludge
                TF   - Trickling Filter
                SEP  - Separated Sanitary Sewers
                COM  - Combined Storm & Sanitary Sewers
                                           376

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TABLE 2.  1976 AVERAGE PERFORMANCE - MAJOR WASTEWATER  TREATMENT WORKS
         ATLANTA, GEORGIA METROPOLITAN AREA

WPCP Facility Name
Flint River #1
Flint River #2
South River
Intrenchment
Snapfinger
Big Creek
Chattahoochee
Clayton
Utoy Creek
South Cobb
Camp Creek




Treated Flow
mgd m3/s
2
8
14
12
15
2
9
79
13
8
4
.5
.3
.3
.4
.0
.8
.9
.7
.7
.3
.4
0.
0.
0.
0.
0.
0.
0.
3.
0.
0.
0.
11
36
63
54
66
12
43
49
60
36
19
Inf.
BOD5
mg/1
194
202
210
202
184
120
238
146
150
153
95
Eff.
BOD5
mg/1
34
43
27
35
26
11
63
41
23
40
22
Inf.
SS
mg/1
140
330
149
122
194
124
460
171
177
143
119
Eff.
SS
mg/1
34
94
47
30
20
9
114
74
42
48
28
Eff.
PH
SU
7
7
7
6
6
6
6
6
7
6
6
.2
.6
.3
.9
.8
.7
.8
.6
.0
.4
.5
Effluent
Fecal
Colif orm
No./lOO ml
420
75
230,000
1,400,000
60
4
76
790,000
540
140
	
ABBREVIATIONS:  Inf.
               Eff.
               SS
               SU
- Influent
- Effluent
- Suspended Solids
- Standard Units
                                           377

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      The radiotracer technique  developed
by Tsivoglou^, which is the  only direct
measurement of reaeration in natural
streams, was used in the model development
on all three of these rivers.  The  tech-
nique5uses three tracers simultaneously:
krypton-85, as a dissolved gas,  is  the
tracer for dissolved oxygen; tritium, as
water molecules, is the tracer for  dis-
persion; and rhodamine - WT  fluorescent
dye provides information on  time of flow.
The ratio of relative gas transfer  capa-
bilities of krypton and oxygen,  measured
as their respective reaeration coef-
ficients, is 0.83, with krypton  transfer
being the slower process.  By measuring
of the loss of the krypton tracer to the
atmosphere and accounting for in-stream
dispersion, a direct correlation to oxygen
transfer is obtained.

      The mathematical model used for each
stream was a modified Streeter-Phelps
equation which accounted for reaeration,
carbonaceous oxygen demand, nitrogenous
oxygen demand, and benthic oxygen demand.
The model was steady-state and one-
dimensional.  The model for  each stream
was calibrated to verify measured field
data and was then used to predict the
responses of the stream under future con-
ditions of wastewater flows and  treatment
levels.  Computer programs were  used to
test a wide variety of alternatives in
each of the models.

      Uniform effluent limits were
established for all major wastewater dis-
charges in the Flint River and the  South
River Basins.   The effluent  limitations
were:  BODr not to exceed 10 mg/1,  ammonia
nitrogen not to exceed 2 mg/1, total phos-
phorus not to exceed 1 mg/1, and dissolved
oxygen not less than 6 mg/1.  The phos-
phorus limitation was established for
treatment works in the South River  Basin
to reduce eutrophication of  a popular
recreational lake some 64 km (40 miles)
downstream.  The phosphorus  limitation was
imposed on treatment works in the Flint
River Basin so that reasonably high treat-
ment would be applied to upgrade the
quality of the Flint River which is used
for water supply downstream  from the
Atlanta Metropolitan Area.
       Both the Flint River and the South
River  are  unregulated streams and are
quite  small,  with their headwaters
rising in  the Metropolitan Area.   The
Chattahoochee River, however, with a
drainage area of 3760 sq.  km. (1450 sq.
mi.) at Atlanta is a highly regulated
stream due to the generation of hydro-
electric power upstream from the  Metro-
politan Area.   The Chattahoochee  River
receives wastewater discharges from the
sewer  systems of three county govern-
ments  and  the City of Atlanta. In
addition to its widely fluctuating flow
regime, the Chattahoochee  River has sig-
nificant withdrawals for local water
supplies and  is used as once-through
cooling water  for two major steam electric
generating  plants which serve the area.
Taking  into account the effects of all of
these  conditions,  the State again con-
structed mathematical water quality models
of the  Chattahoochee River and determined
that a minimum of  21.2 m3/s (750  cfs)  of
water would be needed in the Chattahoochee
River just  downstream from the City of
Atlanta's water supply pumping station in
order to maintain an acceptable stream
quality for a  "fishing" classification.
In order to meet  fishing standards at  a
minimum flow  of 21.2 m-^/s  (750 cfs) on the
Chattahoochee  River,  it was necessary  to
establish a uniform treatment  level
through the mathematical modeling process
for all major  dischargers,  assuming a
minimum river  flow of 21.2 m /s (750 cfs).
All dischargers were required  to  achieve
a level of  treatment  higher than  the EPA
established secondary treatment standards.
The effluent quality to be met by the  dis-
chargers on the Chattahoochee  River is:
BODr not to exceed 17 mg/1,  ammonia
nitrogen not to exceed 5 mg/1, and dis-
solved oxygen  not  less than 6  mg/1.

      The results  of  the mathematical
modeling and waste load allocation
processes for  these three  rivers were
incorporated  into  the State's  water
quality management plans required under
Section 303(e)  of  PL 92-500.   These
limitations were  also written into the
discharge permits  for all  affected treat-
ment facilities  and information from these
studies was incorporated into the  local
government  discharge ranking system which
is used to  prioritize projects for
Federal construction grants.   Through  the
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planning process, and as a result  of  the
important water uses downstream  from  the
Atlanta area in all directions, it  has been
determined that every publicly owned
treatment facility, whether presently
existing or planned for the future, will
have  to achieve effluent quality higher
than  secondary treatment.

       DETAILS OF FUTURE SYSTEMS

      Solutions to meeting the necessary
water quality standards and complying with
the effluent limitations established  by
the State have been developed by several
of the major dischargers through the
facilities planning process of the Federal
construction grant program.  Facilities
planning, as required by Section 201  of
PL 92-500, has not been completed  for all
sewer service areas within the Atlanta
Metropolitan Area, but a considerable
portion of such planning has been  done.
The trend in the metropolitan area is
toward construction of large regional
treatment works with extensive service
areas, since these systems offer signifi-
cant  economies of scale.  A variety of
technical solutions to meet the required
effluent limitations has been developed by
consulting engineers retained by the  local
governments.

      Two treatment facilities discharging
to the Chattahoochee River will  be the
first to be upgraded and expanded  in  the
Atlanta area..  The Chattahoochee Water
Pollution Control Plant (WPCP),  which
receives wastewater from two cities,  and
unincorporated areas of two counties, has
an expansion from 0.44 m /s (10  mgd)  to
0.88  m-'/s (20 mgd) under construction.
The facility, which currently utilizes
a conventional activated sludge  process
and anaerobic sludge digestion, will
convert its aerobic digesters to addition-
al activated sludge basins.  Plastic  media
nitrification towers with pH adjustment
capability will be added to reduce ammonia
concentrations following the activated
sludge process.  Expected final  effluent
quality is:  BODc not exceeding  17 mg/1,
NH-^N) not exceeding 5 mg/1, and suspended
solids not exceeding 30 mg/1.  Sludge will
be anaerobically digested and dewatered in
filter presses, with the filter  cake  being
incinerated.  The incinerator will be
fueled by digester gases.
      The South Cobb WPCP,  which treats
wastewater from five cities and  portions
of two counties, will be  expanded from
0.35 m3/s (8 mgd)  to 1.05 m3/s  (24 mgd).
The existing conventional activated sludge
system will be expanded and converted to
use pure oxygen aeration, combining carbo-
naceous removal and nitrification in one
process.  Pure oxygen gas will be gener-
ated by a 2900 kg/day (32 ton/day)  cryo-
genic plant, and liquid oxygen storage
will provide a backup supply.  The South
Cobb WPCP will meet the same final efflu-
ent limits as the  Chattahoochee  WPCP.
Undigested sludge  will be gravity thicken-
ed, heat dried in  rotating  kilns,
pelletized and bagged for use as a fertil-
izer and soil conditioner.

      All wastewater currently being dis-
charged to the Flint River  will  be
removed.  Effluents from  the Flint River
WPCP #2 and a smaller facility nearby  will
be disposed on land by spray irrigation.
The effluents from the Flint River WPCP #1
and another smaller facility will be
pumped with effluent from two facilities
in the South River Basin  to the
Chattahoochee River.  These actions will
be particularly beneficial  since the Flint
River Basin is the most severely water
quality limited and the smallest of all
of the major drainage basins in  the
Metropolitan Area.

      Engineering  analysis  showed that it
would be more cost-effective (cost-ef-
fectiveness is determined by comparing the
present worth of treatment  alternatives)
to construct a land application  system
than to provide the advanced levels of
treatment required for stream discharge.
The Flint River WPCP #2 will be  expanded
to provide secondary treatment for  future
population needs and the  effluent will be
sprayed onto an area of land which is
tributary to the surface  water supply  of
the same authority which  owns this  plant.
Thus, this local government, which is
predicted to have  future  water shortages,
will actually be recycling  a large
portion of its wastewater,  since approxi-
mately 90 percent  of the  water which falls
onto the spray fields will  ultimately  find
its way back into  surface streams through
groundwater channels.  The  authority will
also grow trees in the land application
                                           379

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area which will be harvested and sold to
pulp and paper companies.  The project will
consist of pumping an average of 0.85 m /s
(19.5 mgd) of wastewater which has
received conventional secondary treatment
to a storage reservoir which will have
sufficient volume to store 12 days of
waste flow.  The water will then be pumped
onto wooded areas of sandy clay soil
through a sprinkler distribution system
approximately 488,000 m  (1,600,000 ft.) in
length.  The year-round application rate
will average 6.35 cm (2.5 in.) per week
and the total wetted area of land will be
approximately 955 ha (2360 acres).  The
authority will have to acquire approxi-
mately 1420 ha (3500 acres) of land to
allow adequate buffer areas around exist-
ing homes and roads.

      In the South River Basin, the
largest existing facility is the
Snapfinger WPCP which will be upgraded and
expanded to 1.58 m /s (36 mgd) to meet
future population needs, and will con-
tinue to discharge to the South River.  To
meet the required effluent limits of BOD5
= 10 mg/1, NHo(N) = 2 mg/1 and total phos-
phorus = 1 mg/1, the facility will employ
the following processes:  chemical
precipitation in primary clarifiers using
lime for removal of organic materials;
aeration basins for biological nitrifi-
cation to remove ammonia; post-chemical
precipitation for phosphorus removal; and
dual-media filtration for suspended
solids removal.   Post-chemical sludge will
be classified by centrifuges, recalcined,
and reused.  Primary and nitrification
sludges will be filter pressed, with the
filter cake being incinerated.

      The City of Atlanta, largest local
government in the metropolitan area, has
wastewater treatment facilities in the
Flint River, South River, and the
Chattahoochee River Basins.  Faced with
providing advanced wastewater treatment
(effluent limits identical to those from
the Snapfinger WPCP) for its South River,
Flint River #1,  and Intrenchment Creek
WPCP's, Atlanta selected a plan which will
divert the effluents of those facilities
a distance of some 16.1 km (10 mi.)
through underground tunnels, back to the
Chattahoochee River from which the water
originated.  In doing this, Atlanta has
the advantage  of  providing a lower  level
of treatment  (BOD5  =  15  mg/1,  NH3(N) =
4 mg/1, and no limit  on  phosphorus) for
these effluents than  it  would  have  if it
had left them  in  the  Flint and South
Rivers.  The City will have substantial
economic benefits by  reducing  the annual
operating costs below those which would be
required for operating more advanced
treatment systems.  In addition, the Three
Rivers proposal will  provide retention and
partial treatment for wastewater from
three combined sewer  overflows in the
South River Basin.

      All owners  of wastewater treatment
and collection systems in  the  Atlanta
Metropolitan Area,  other than  those
discussed in the  preceding paragraphs,  are
in various stages of  detailed  planning to
determine what actions may be  necessary to
meet future needs and to comply with
effluent limits established through the
State's planning  processes.  Availability
of grants from the U. S. Environmental
Protection Agency to  pay for 75 percent of
the costs of planning, design, and con-
struction assures the continued interest
and cooperation of  the local governments
in these programs.

      REGIONAL-AREAWIDE  WASTEWATER
            MANAGEMENT PLAN

      The Atlanta Regional Commission(ARC)
is the regional planning and intergovern-
mental coordinating agency for 46 local
governments in the Atlanta Metropolitan
Area,  The Commission has  a full-time
technical staff which has  the  responsi-
bility for preparing  regional  plans for
transportation, land  use,  health, social
services, water supply,  and wastewater
management.  However, ARC  does not have
the authority  or  responsibility to
implement the  plans.  The  46 local govern-
ments must implement  various plans
developed by ARC; however,  the intergovern-
mental cooperation  that  is essential to
the implementation  of a  plan is often
accomplished through  ARC.

      Recognizing the complexities of
wastewater management and  the  fact that
natural drainage  areas often cross several
local government  boundaries, the ARC
requested assistance  from  the  Federal and
                                            380

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State governments in the development  of
a comprehensive plan.  In 1973  the  joint
effort was initiated.  While the ARC's
technical staff emphasized coordination of
local governments within the region and
the solution of their problems, the Feder-
al and State agencies placed emphasis on
evaluating the impact of ARC's  wastewater
and water supply plans on areas outside
the region.

     The Federal agencies (EFA and Corps
of Engineers) conducted portions of the
study that produced statistical data  to
guide the selection of the most cost-
effective alternatives.  An in-depth
evaluation of the stream flows  of the
area was made and predictions for minimum
flows were developed.  The State conducted
stream studies to verify existing water
quality and through computer modeling
determined allowable waste loads.   Utiliz-
ing the construction grant funds provided
to the State under Section 201  of
PL 92-500, the State has worked with  the
local governments to initiate imple-
mentation of the recommended modifications
and improvements to the publicly owned
treatment works in the region.

     During 1976 and in accordance with
Section 208 of PL 92-500, the State
designated the region served by ARC for
the development of an areawide  wastewater
management plan and designated  ARC  as the
agency to develop the plan.  Many of  the
improvements needed in the region's system
of point wastewater sources have begun to
be implemented as a result of State
requirements and the regional study con-
ducted between 1973 and 1976.   Efforts
under the 208 study will concentrate  on
development of a plan to control or
minimize non-point source pollution.
Pollution from urban runoff, which
includes soil-erosion, sewage from  com-
bined sewers, storm drainage from
commercial districts, infiltration  and
inflow to sanitary sewers, and  debris from
the streets, will be studied.   Alterna-
tives will then be recommended  to reduce
non-point source pollutants.  Preliminary
studies indicate the non-point  source
pollutants contribute as much as 50 per-
cent of the pollutional load to the
streams in Atlanta region during periods
of high rainfall.  Since the existing
point sources receive  biological treatment
already, the additional  reduction from
point sources will be  small  and very
expensive which makes  it imperative that
the 208 study produce  cost-effective
alternatives to reduce and control non-
point source pollution.

            WATER SUPPLY PLAN

      An adequate and  dependable water
supply for any community is  essential for
the health, safety, and  economic well-being
of the region.  In the Atlanta region the
geological formations  are such that
groundwater is unavailable.   Therefore,
the region is dependent  on surface waters
as a source for water  supply.   The
drainage divide through  the  Atlanta
region, with the Chattahoochee River being
the only river which flows through the
region, further limits available water.
The necessity of maintaining a minimum
streamflow past Atlanta  for  the
assimilation of treated  wastewater from
the region further reduces the available
supply.

      With the projected population of
3.5 million by the year  2000 and the
established minimum flow for assimilation
of treated wastewater  of  21.2  m^/s (750
cfs), the development  of  a plan to provide
for realistic alternatives to  meet the
water needs of the region had  become
critical by the mid 1970's.   Since the
Chattahoochee River has  a hydroelectric
facility about 77.2 km (48 miles)  above
Atlanta, an evaluation was made of the
reservoir to determine the maximum
sustained yield that could be  provided
during drought conditions.   The maximum
sustained yield for a  drought  condition
comparable to the most severe  drought of
record was determined  to  be  51.0 m /s
(1800 cfs).  In order  for the  region's
peak day demand by the year  2000 of
29.7 m3/s (1050 cfs) to  be met under
drought conditions, two  alternatives have
been identified as realistic.   One
alternative is to construct  a  smaller re-
regulation dam about 9.65 km (6.0 mi.)
downstream of the existing hydroelectric
facility.  A second alternative is to
modify the operation of  the  existing
hydroelectric facility to provide a
constant flow of at least 51.0m3/s
                                           381

-------
(1800 cfs) at all times.  Both of these
alternatives are presently under further
economic and environmental study.  In the
meantime, a slight modification in the
operation of the hydroelectric facility
has assured the region of the needed water
until the 1985-1987 period.

      FEDERAL-STATE-REGIONAL EFFORTS

      The comprehensive three year effort
by Federal, State, and Regional agencies
has produced implementable plans for
management of wastewater and water supply
systems for the Atlanta region through the
year 2000.  Local governments in the
region must now implement the plans under
the guidance of the State and with the
assistance of ARC.  Local governments must
begin requiring conservation of water
through education of their citizens and
establishment of new plumbing codes.  The
Federal agencies must continue to
participate in these efforts to assure an
adequate water supply to the region and
an approvable non-point source pollution
control strategy.  In the final analysis,
it has been determined that the water
resources of the Atlanta region may be
the controlling or limiting factor for the
region's future instead of energy or other
resources.
5.   Tsivoglou, E. C., and Wallace, J.  R.,
    "Characterization of Stream Reaeration
    Capacity", EPA-R3-72-012.  EPA,
    Washington, D.C. (1972).
REFERENCES

1.  "Atlanta Region Areawide Wastewater
    Management Plan",  Metropolitan Atlanta
    Water Resources Study,  Atlanta Region-
    al Commission (1976).

2.  "Water Supply Plan for  the Atlanta
    Region", Metropolitan Atlanta Water
    Water Resources Study,  Atlanta Region-
    al Commission (1976).

3.  "Storm and Combined Sewer Pollution
    Sources and Abatement", U. S.
    Environmental Protection Agency,
    Atlanta, Georgia (1971).

4.  Tsivoglou, E.G., and Neal, L.A. ,
    "Tracer Measurement of  Reaeration:
    III.   Predicting the Reaeration
    Capacity of Inland Streams."  Jour.
    Water Poll. Control Fed., 48, 2669
    (1976).
                                           382

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                                 REGIONAL  SOLUTIONS  TO
                            DOMESTIC WASTEWATER  MANAGEMENT
                                       R. S.  Burd
                    U.S. Environmental  Protection  Agency,  Region X
                                   1200 Sixth  Avenue
                            Seattle, Washington  98101   U.S.A.
                                       ABSTRACT

     Regional solutions to wastewater collection  and  treatment are discussed in terms of
encouraging their adoption.  Problems encountered in  implementing regionalization are
identified as are the many advantages that  can  be gained  if these problems are overcome.
A number of important issues that should be considered  in any regionalization effort are
discussed.
              INTRODUCTION

     The creation of regional agencies to
collect and treat wastewater is usually a
difficult and painful process.  There are
many reasons for this-but-the following are
among those most frequently encountered.
Existing wastewater collection and treat-
ment jurisdictions are very reluctant to
give up their responsibilities-and-if they
do,  often maintain bitterness over lost
responsibilities for a long period of time.
And, a new regional agency inherits all of
the  politically based hostilities of its
constituencies.  If these and other problems
can  be overcome, there can be real advant-
ages to regionalizing wastewater management
systems.

               BACKGROUND

     Much of the time regional solutions to
regional problems are defended on the basis
of their value to protecting the environ-
ment.  This is because a large number of
environmental  concerns do not respect the
artificial  boundaries of cities and counties
as such; they must be attacked regionally
on the basis of river basins or air sheds
for  example.  However, the most compelling
arguments on behalf of regional wastewater
management may be economic and political
rather than environmental.

     Regionalization in the wastewater field
is not new.   There are many agencies in
large urban areas of the U.S.A. as well as
Europe that have long histories in water
pollution control.  Recent Federal legisla-
tion has encouraged regionalism by promoting
the development of regional waste management
plans and by encouraging the most cost-
effective solution to wastewater collection
and treatment.

     Concerning the latter, it just didn't
seem economical to have two wastewater
treatment plants, perhaps even across the
street from one another, separated by
jurisdictional boundaries.  Historically,
most large urban areas of the U.S.A. had
many—many highly independent political
jurisdictions.  Over the years some pro-
gress was  made in waste management through
the formation of semi-autonomous sewer dis-
tricts throughout an area.  Further, inter-
community sewerage agreements were started
between a number of area communities in
particular urban centers.  But, while these
steps represented some improvement, many
problems remained.

      REGIONALIZATION CONSIDERATIONS

     A successful regional wastewater man-
agement agency usually has the following
characteristics:

     1.  The agency fills a clearly defined
and recognized need.
                                           383

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     2.  There is a strong personal commit-
ment to regionalization on the part of the
elected officials and key members of insti-
tutions that are involved.

     3.  A sound financing program exists
which is equitable for all users.

     There are two major concepts of region-
al ization.  The first concept is one where
the regional agency acts as a wholesaler of
services to existing jurisdictions.  These
jurisdictions then continue to deal with
the public on a "retail" level.  The second
concept is a complete consolidation, wherein
the regional agency provides the service
and deals with the public as a customer.
In creating a wholesale/retail concept of
regionalization, one of the more difficult
aspects is to determine which resources be-
long to the regional agency and which to the
surviving local jurisdictions.

A most important consideration is that of
properly structuring the governing Board
or Commission to manage the agency.  The
governing body should be responsive to the
public if the agency has taxing authority
then it may need equal representation, i.e.
"one man, one vote".  If the smallest
jurisdiction in a regional authority has
one vote, then the larger jurisdictions
must have a proportionately larger vote.

     Financial considerations leading to
regionalization decisions include a look
at the status of each agency in terms of
whether they will benefit from regional
service and a  look at the equity each may
have in the present sewers and treatment
plants.  Future funding for regional
agencies eases financial problems because
the Federal and State governments providing
grants can deal with one entity.  It avoids
the technical and political problems of
trying to resolve conflicts between dif-
ferent agencies not wanting to become part
of a regional system.

     But, at EPA, if we think a regional
system is the cost-effective way of pro-
viding wastewater collection and treatment
of domestice waste we use economic incentives
to force the issue.  That is, we refuse to
award the 75% construction grant if the
political jurisdictions don't get together.
Or, if a city was awarded a grant on the
basis it would serve as a regional facility--
and then--it refuses to accept another
cities waste  for  political  reasons  (such
as insisting  on annexation  first),  we refuse
to make payments  on  the  grant or  to award
future grants.  These  financial incentives
plus an incentive often  used  by State
governements—a ban  on new  connections to
existing sewers—usually forces a favorable
regionalization decision.

     Another  problem to  consider  in region-
alization decisions  is one  of people.
Preserving the identity  of  workers, managers
and public board  members who  represent
agencies that are affected  by regional
plans is important.  It  is  often good
practice to accept existing staff and
retrain them  if necessary.

                ADVANTAGES

     There are a  number  of  advantages
possible with regional wastewater manage-
ment systems.  First,  there are economies
of scale, both for the capital investment
and for the operation  and maintenance
expenses.  Also,  cities  may be able to
transfer their debt  for  capital costs to
a regional authority where  it can be handled
easier.

     There are water quality  advantages  to
regional  system.   It can  eliminate multiple
discharges that are  at the  wrong point
and are causing water  pollution.  Regionali-
zation can provide more  flexibility in
treatment plant operation and—being a
larger system—probably  can support a
budget for better  operation and maintenance.
Consolidation of  technical  and financial
resources could allow  for problem solving;
i.e.  some RSD work.  Finally,  there is a
likelihood that the  growth  and development
of an urban area will  be  more orderly than
if small  individual  jurisdictions were pro-
viding sewerage service.

     In summary,  forming  regional  wastewater
management systems can be cost—effective,
provide for compliance with water quality
standards, and it  can  provide a high level
of political  and managerial experience
and accountability.
                                            384

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                  URBAN RUNOFF POLLUTION  CONTROL TECHNOLOGY OVERVIEW
                                      C.
                                      R.
                                      H.
                                      A.
B.
I.
E.
N.
Brunner
Field
Masters
Tafuri
                      Municipal Environmental  Research Laboratory
                           Office of  Research  and Development
                          U.S. Environmental Protection Agency
                                 Cincinnati, Ohio 45268
                                        ABSTRACT

     This Overview describes the major  elements of the Urban Runoff Pollution Control
Program.  Problem Definition, User Assistance Tools,  Management Alternatives and
Technology Transfer are covered, including some of the highlights of the Program's
future direction and products from over 150 of its research projects.  References are
cited for completed Program reports,  ongoing Program projects, and in-house documents.
Capital cost comparisons for storm and  combined sewer control/treatment are given, along
with a specific example of cost-effective  solution for urban runoff pollution control by
in-line storage in Seattle.  In a study done in Des Moines, using a simplified receiving
water model, four control alternatives  were compared, considering cost and effectiveness
in terms of a frequency of D.O. standard violations.
              INTRODUCTION

     Control and treatment of stormwater
discharges and combined sewage overflows
from urban areas are problems of increas-
ing importance in the field of water
quality management.  Over the past decade
much research effort has been expended  and
a large amount of data has been generated,
primarily through the actions and support
of the U.S. Environmental Protection
Agency's Storm and Combined Sewer Research
and Development Program.

     The products of the Program  (Figure
1) are divided into the following areas,
common to the major elements of Combined
Sewer Overflow Pollution Control, and
Sewered and Unsewered Runoff Pollution
Control:  Problem Definition, User
Assistance Tools (Instrumentation,
Computers) , Land Management, Collection
System Control, Storage, Treatment, Sludge
and Solids, Integrated Systems, and
Technical Assistance and Technology Transfer.
          Table 1 breaks down these  categories
     into more specific elements.  There  have
     been about 150 projects under the  Program.
     References are cited  for completed Program
     reports  (numerically  indicated), ongoing
     Program projects  (indicated by  "P" numbers),
     and in-house and miscellaneous  documents
     (indicated by "R" numbers).

                 PROBLEM DEFINITION

          The program starts with  "Problem
     Definition" broken into "Characterization"
     and "Solution Methodology"  (Figure 2).

          The background of sewer  construction
     led to the present urban runoff problem.
     Early drainage plans  made  no provisions for
     storm flow pollutional impacts.  Untreated
     overflows occur from  storm events  giving
     rise to the storm flow pollution problem.

          Simply stated the problem  is:
                                           385

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COMBINED
  SEWERS
 INFILTRATED
SAN. SEWERS
   I
STORM
SEWERS
                                                                        I
UNSEWERED
  RUNOFF
 HYDROLOGIC  j
MODIFICATIONS'
                  COMBINED SEWER
                POLLUTION CONTROL
                           SEWERED & UNSEWERED
                                  RUNOFF
                            POLLUTION CONTROL
                               RUNOFF POLLUTION
                              CONTROL PROGRAM
           •PROBLEM DEFINITION
           • USER ASSISTANCE TOOLS
              INSTR. & COMPUTERS
           •LAND MANAGEMENT
           •COLL. SYS. CONTROL
                            • STORAGE
                            • TREATMENT
                            • SLUDGE/SOLIDS
                            • INTEGRATED  SYSTEMS
                            • TECHNOLOGY TRANSFER
                    Figure 1.  EPA Storm and Combined Sewer R&D Program

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CATEGORIES
PROBLEM UIUHM1QN
Characterization
Solution Methodology
USER ASSISTANCE TOOLS
Instrumentation
Simulation Models

LAND MANAGEMENT

Enforced controls
Neighborhood sanitation
COLLECTION SYSTEM CONTROLS
Sewer separation
Sewers
tide gates
Remote monitoring with
STORAGE
In-Line

("REATMENT
Biological treatment

Physical-chemical
Disinfection
Land disposal
SLUDfcEVSULfDS
Characterization/Quanti-
fication
Treatment handling schemes

Caries)
Storage/treatment
Dual use WUF/DWF (storage/
treatment

fECHNICAL ASSISTANCE AND
TECHNOLOGY TRANSFER'
Consultation to Fed. .
quasl-govt. agencies

Public Inf. Requests
Consultation to foreign
govtt and International
confer.
In-House seminars
5WMM
Higher Education
Planning/design/SOTV
assess manuals and extra-
mural publications
INITIATED/ ACCOMPLISHED
Prelim, appraisal s CSO/SU prob. . CSO/SW char. .
deicing, sed./eros., loading factors, rec. water
SOTA 5i« tech., plan/select guide, conduct of SU
studies, SOTA's sed./eros. S deicing control, unit
Raingage, flow measuring, sampling, monitoring,
control
Simplified, detailed/complex, operational.

NON-STRUCTURAL:
tural), porous pavement
Air pollution, eros./sed., cropping, berms, chemical
Street cleaning, solid waste management
May require separate treatment system
"First flush" relief: flushing/cleaning, new designs
{low flow carrying vel . and added storage), I/I pre-
vent and control (with manuals), polymers to In-
crease capacity
swirl & helical, fluidic reg.
Provides storage/discharge options

tunnels), underwater, solids impacts

Contact stabilization, trickling filters, lagoons,
w/continuously operated plant
Precipitation, filtration, adsorption, ion exchange,
break-pt Cl?
dioxide, on-slte gen., high-rate, mixing, micro-
organism indicator study (pathogen, virjs), 2-stage
Marsh land
Classification requirement, treatabil i ty, vital
On-site vs DWF tnnt.. land disposal
tion, incineration
Pump-back, sed. In storage, disinfection, break-even
econ. w/treatment
Lagoon storage/treat., HRTF, contact stab., P-C, hi-
rate filter, equalization, combined sewers
treat. /reuse
EPA, OAWP (needs surveys): EPA TT (seminars, film
EPA Hq and Regions on 201/208 studies and seminars;
Reg. V on 108 grants; NSF, DOT, OURT (reviews,
and rept reviews, joint nat'l assess, projects)
ports, example methodology for prob. solution, conf.
moderator, prog, committees
TT (France, Japan, Denmark, Norway, Sweden, Canada,
Netherlands, Australia, New Zealand); Canadian (TAG)
IJC (steering com.) IAUPR (confer. & prog, commit-
tees); various conferences and publications
Varioi/s tech. areas; overviews
Short course,; user's assistance manuals/dissem-
ination
SCS prog, university course man.
Overall prog, concepts, sol. method, sampling/anal.,
costs, specific processes
ONGOING
-Direct rec. water/source loading factor analys.s
-Dev. SSCS strategy document
-Analyze optimum SSCS/DWF T/C combinations

-Verif. magnetic flowmeter for simultaneous press/
gravity flow meas. (supplement)
-Demo in-situ TOC anal. 4 storm flow sampler
-Dev. syst. analysts program for quantification/hand-
ling of CSO sludge/solids
-Oev. autom. oper. model for real-time control w/raln
fall predict.

stream det./ret.
-Demo in-situ hydrophobic substance
-Demo sed./eros . control techniques in SE USA
(suppl ement)
-Demo periodic sewer flushing. CSO 1st flush relief
concrete pipe
-Dev. autom. operational model for real-time control
w/rainfal 1 predict.





high-rate disinf by CKWClj, and mixing incl:
resid. toxic/carcinogenic Cl-j comp. viral disinf.
-Feas. of land disposal (Envirex-supplement)



-Evaluate: methods of ultimate disposal of WWF solids
and impacts of WWF sludges/solids on DWF plant
(Envirex-supplement)




-Continuous (IBS - 20% of prog, time)
(201) and planning grant (208) assist.
due to CSO emphasis







Table 1.  Summary Storm and Combined Sewer Program
                         387

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                          PRE-FY76
                                                                     FY76
                                                                                                                   FUTURE
00
00
                   CHARACTERIZATION
       •PRELIM APPRAISALS  CSO/SW PROS
       •CSO/SW CHARACTERIZATION
         -FLOW
         -LAND LOADING  FACTORS(D/D ACCUMUL
         -POLLUTANT  CONCENTRATIONS
       •REC. WATER IMPACT  PREDICTIONS
       •DEICING CHEMICALS
       • SEDIMENT/EROSION
       •PATHOGEN ANALYSIS
       • NATIONWIDE CONTROL/COST ASSESS
       •DATA BASE
DIRECT REC.  WATER/SOURCE
       LDG. ANAL
    ADDITIONAL REC.  WATER/
OPTIMIZED SOURCE LDG FACTORS
                SOLUTION METHODOLOGY
       • SOTA'S FLOW MEAS
          -FLOWRATE
          -SAMPLING/IN SITU ORG
       • SOTA DEICING  CONTROL
       • SOTA SEDIM/EROSION CONTROL
       •8-CITIES  ECON./SOLUTION  COMPARISONS
       • SOTA S&CS TECHNOLOGY  AND  FILM
       •MANUAL: STORM FLOW  RATE &
        VOL DETERMINATION
       •GUIDE FOR  CONDUCT OF SW STUDIES
       • PROCESS COST FACTOR DEV
       •GUIDE FOR  URBAN PLAN/COR RECTI ON;
        INCLUDE REC. WATER OBJECTIVES
        • CITY-WIDE DEM.
 DEV  S&CS STRATEGY DOC
        (IN-HOUSE)
 ANALYZE  OPT. S&CS/DWF
  T/C  COMB.  (IN-HOUSE)
                                                          MANUAL:  REFINED SOLUTION
                                                                METHODOLOGY
                                    NAT'L ASSESS PLAN GRANTS
                                                    Figure  2.   Problem  Definition

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  200
              200
        BOD
                    SS
                                      \  COMBINED

                                    I   I  STORM
                                     6-7
                                DO
5*107
        H|  RAW

        ¥77\  COMBINED

        I   I  STORM
                          10
   TOTAL COLIFORM    TOTAL
     MPN/100 ml     NITROGEN
  TOTAL
PHOSPHORUS
Figure  3.  Representative Strengths of
            Wastewaters  (Flow Weighted
            Means  in mg/1)
                     389

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     "When a city takes a bath, what
      do you do with the dirty water?"

     Four types of discharges are involved:
combined sewer overflows  (CSO), storm
drainage in separate systems, overflows
from infiltrated sanitary sewers and
unsewered runoff.  Because of the inability
to control the latter, it is usually for-
gotten.  Significantly, the storm path
and collection system configuration may
have a pronounced influence on combined
overflow quality, resulting in simultaneous
discharge mixtures of sewage and runoff at
different points, varying from raw to
highly diluted as the system adjusts to a
particular storm pattern.  The problem
constituents of general concern are
visible matter, infectious bacteria,
organics, and solids and in addition may
include nutrients, heavy metals and
pesticides.

Characterization

Representative Concentrations

     Figure 3 gives some representative
concentrations for comparison purposes.
As shown the average BOD concentration in
combined sewer overflow is approximately
one-half the raw sanitary sewage BOD.
However, storm discharges must be
considered in terms of their shockloading
effect due to their great magnitude.  A
not uncommon rainfall intensity of 1 in./
hr. will produce urban flowrates 50 to
100 times greater than the dry-weather
flow (DWF) from the same area.  Even
separate storm wastewaters are significant
sources of pollution, "typically" charac-
terized as having solids concentrations
equal to or greater than those of untreated
sanitary wastewater, and BOD concentrations
approximately equal to those of secondary
effluent.  Bacterial contamination of
separate storm wastewaters is typically
2 to 4 orders of magnitude less than that
of untreated sanitary wastewaters.  Signi-
ficantly, however, it is 2 to 4 orders of
magnitude greater than concentrations
considered safe for water contact activi-
ties.

     Microbiological studies of both
sanitary sewage and storm runoff have
shown a consistently high recovery of
both pathogenic and indicator organisms
(160).   The most concentrated pathogens
were Pseudomonas  aeruginosa and Staphy-
lococcus aureus at  levels  ranging  from
103 to 105 and from 10°  to 103/100 ml,
respectively.  Salmonella  and entero-
viruses, though frequently isolated were
found at levels of  only  10° to 104/10
liters of urban runoff.  This strongly
indicates that all  types of urban  runoff,
in general, can be  hazardous to health.

     Past characterization studies for
storm flow provide  a data  base for
pollutant source  accumulation,  and
hydraulic and pollutant  loads (2,  20, 34,
35, 41, 47, 51, 53,  54,  59,  60,  63, 65,
67, 73, 81, 82, 83,  88,  102,  123,  124,
127, 128, 143, 149).  A  computerized data
base and retrieval  system  has been developed
for urban runoff  (P-49).   The data base
contains screened and reasonably accurate
data that is intended for  model  verification
and future study  area data synthesis —
especially useful to 201 and 208 (Section
208, PL 92-500) planning agencies.

     Besides the  more generalized
characterization  studies,  specific studies
have been carried out for  deicing salt
(67, 109, 86), and  sediment/erosion (129).

Representative Loads

     From 40% to  80% of  the  total annual
organic loading entering receiving waters
from a city is caused by sources other
than the treatment  plant (R-l).  Assuming
treatment plants  are operating properly,
during a single storm event,  from 94% to
99% of the organic  load  and  almost all
settleable solids are attributed to wet-
weather flow (WWF)  sources (R-l) .

     The runoff of  toxic pollutants,
particularly heavy  metals,  is also high —
considerably higher than typical indus-
trial discharges.   For example,  New York
Harbor receives metals from treatment
plant effluents;  discharges  from combined
sewer overflows and separate storm sewers;
and untreated wastewater included  in the
CSO and from sewered areas not yet served
by treatment plants.  As can be  seen in
Table 2, urban runoff is the major
contributor of heavy metals  to the
Harbor (R-2).

Potential Impacts

     Approximately  one-half of the stream
miles in this country are  water quality
                                            390

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         TABLE 2 - METALS DISCHARGED  TO  THE  HARBOR FROM NEW YORK CITY SOURCES
SOURCE
Plant effluents
Runoff*
Untreated wastewater
Total weight (Ib/day)
Weighted average concentration (mg/1)
Cu
1,410
1,990
980
4,380
0.25
Cr
780
690
570
2,040
0.12
Ni
930
650
430
2,010
0.11
Zn
2,520
6,920
1,500
10,940
0.62
Cd
95
110
60
265
0.015
* In reality, shockload discharges  are much greater.
limited and 30% of these stream  lengths
are polluted to a certain degree with
urban runoff.  Hence, generally  speaking,
secondary treatment of DWF is not  suffi-
cient to produce required receiving water
quality; and control of runoff pollution
becomes an alternative for maintaining
stream standards.  Accordingly,  both
water quality planning and water pollution
abatement programs need to be based on an
analysis of the total urban pollution
loads.

    Until the urban stormwater  situation
is analyzed and efficient corrective
measures taken, there may be no  point  to
seeking higher levels of treatment
efficiency in existing plants.   For
example:

—In Roanoke, VA domestic waste  load
removal was upgraded from 86% to 93%,
yet there was no dramatic reduction in
the BOD load  (3.2 million pounds before
upgrading, compared to 3.1 million pounds
after)  (41) .

—If Durham, NC provided 100% removal  of
organics and suspended solids from the
raw municipal waste on an annual basis,
the total reduction of pollutants  dis-
charged to the receiving water would only
be 59% of the ultimate BOD, and  5% of
the suspended solids  (112) .

    These examples are for separate
systems.  Communities with combined
systems offer a potentially greater
pollutional impact since additional
loads come from domestic wastewaters,
dry-weather sediment wash-out, and more
impervious and populated lands.

Receiving Water Quality Impacts

    For the aforementioned Durham study
it was found that during storm flows.
dissolved oxygen content of  the  receiving
watercourse was independent  of the  degree
of treatment of municipal wastes beyond
secondary treatment.  Oxygen sag estimates
were unchanged even if the secondary
plant was assumed upgraded to zero  discharge,
and stormwater discharges governed  the
oxygen sag 20 percent of the time.

     There is an R&D study  (P-68) in  the
Milwaukee area to determine  water quality
impacts from wet-weather discharges.  This
study is being conducted in  conjunction
with a Step 1 construction grant (Section
201 of PL 92-500) for the evaluation  of
combined sewer overflow pollution and
control; and will provide the necessary
"receiving water impact" basis for  these
evaluations.

     Early results from direct receiving
water sampling in the Milwaukee  River
provide strong evidence of CSO impacts on
intensifying D.O. sag and increasing  fecal
coliform concentration.  Figure  4 repre-
sents D.O. analyses for the  Wells Street
sampling station that lies at the down-
stream portion of the combined sewer  area.
Samples were collected at three  hour
intervals during 72 hours of dry weather
during June 1975, averaged for the  stream
cross-section, and followed  approximately
nine days of antecedent dry  weather.  D.O.
values hovered around 6 to 8 mg/1.

     Figure 5 is for the same Wells Street
location representing data from  six days
of monitoring following a 0.26 inch rain-
fall on October 14-15, 1975.  Continuous
monitoring at the site showed D.O.  levels
between 5.0 and 7.8 mg/1 for the three days
prior to rainfall.   (The lag between  the
end of the storm and beginning of data
acquisition was due to equipment
                                           391

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malfunction).  The graph  indicates  a highly
significant  D.O. sag to zero mg/1 and six
days after the storm required  for recovery.

     Adverse combined sewer overflow
effects on fecal coliform concentrations
in the Milwaukee River in the  proximity
of Lake Michigan were also deciphered.
Figures 6 and 7 depict fecal coliform in
the Milwaukee River during the same dry-
and wet-weather monitoring periods  as in
Figures 4 and 5, respectively.  Addition-
ally/Figures 6 and 7 contain  the Brown
Deer Road monitoring site which is  well
above the intensely urbanized  combined
sewer overflow area.  There is nearly a
two log increase in enteric microorganisms
downstream in the CSO area after wet-
weather discharges indicating  a potential
health hazard for the nearby Lake beach
fronts.  Brown Deer Road  showed no  signi-
ficant difference in fecal coliform
concentration.

     Due to  Health Department  findings,
shell fishing must cease  in Narragansett
Bay in the vicinity of the Providence,
RI overflows for periods  of seven and ten
days following rainfalls  of one-half  and
one inch, respectively.

     Other studies (P-15, 157, R-3) based
on mass balance effects of urban runoff
in receiving waters have  reinforced
these findings.  A substantial additional
effort is planned to document  the
receiving water impact of urban wet-
weather discharges.

Erosion/Sediment Impacts

     Erosion-sedimentation causes the
stripping of land, filling of  surface
waters, and water pollution.   Urbanization
causes accelerated erosion, raising
sediment yields two to three orders of
magnitude from 1Q2 - 103  tons/sq mi/yr
to 104 - 105 tons/sq mi/yr (164).   At the
present national rate of  urbanization,
i.e., 4,000  ac/day, erosion/sedimentation
must be recognized as a major  environ-
mental problem.

Nationwide Cost Assessment

     Sewer Separation —  The concept  of
constructing new sanitary sewers to
replace existing combined sewers has
largely been abandoned for pollution
control due  to  enormous  costs,  limited
abatement effectiveness,  inconvenience
to the public,  and extended time  for
implementation.   The  use  of alternate
measures for combined sewer overflow
control could reduce  costs  to about one-
third the cost  for separation (2, 102).
It is emphasized  that sewer separation
would not cope  with the runoff  pollution
load.

     High Costs Implied —  However, even
in alternate approaches high costs have
been implied.   The 1974 Needs Survey
(R-4) , the 1967 EPA survey  by the American
Public Works Association  (2), and the
1975 National Commission  on Water Quality
(NCWQ) Report (R-5),  identified national
costs for abating  combined  sewer overflow
pollution at $26 billion, or approximately
one-fourth of the  total for municipal
sewage control.  The  cost of abating
separate stormwater pollution was estimated
at $235 billion by the Needs Survey and
$173 billion (for  75% BOD reduction)  by
another NCWQ report (R-6).

     There must be a  more accurate
assessment of the  problem both  nationwide
and regional to provide the necessary
foundation for policy and law making,
and firmer pollution  abatement  targets —
realistically, can a  job  be done for the
money allotted?

     New R&D Estimates Imply Lower Costs —
The recently completed Nationwide Assess-
ment Report  (157)  has attempted to more
accurately assess  these national cost
estimates by reflecting a more  logical
consideration of such items as: climate,
land usage,  and degree of urbanization;
pollution abatement of storm flow only
and not separate,  conventional  flood
control; appropriate  design flows; and
the benefits of optimized coordinated
systems of smaller storage-treatment
units not taken into  consideration in
earlier estimates.  The resultant
national cost for  combined  sewer overflow
and separate stormwater pollution control
was $23 billion at 75% annual BOD
removal (Curve  A,  Figure  8)(157).  It is
estimated that  the incremental  costs for
combined sewer  overflow pollution
abatement alone would be  $9 billion
(Curve D, Figure  8).
                                            392

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                                    /- -\
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                   Time
             Figure 4. Dry Weather
                   Figure 5.  Wet Weather
                                Dissolved Oxygen  Concentration,  Wells  Street

                                      Milwaukee River,  Milwaukee,  WI

-------
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                     Figure 6. Dry Weather
                       0
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                                                          10
                                                          10
                                                                    We 11s
                                                                                                 Brown Deer
                                                                              Figure 7. Wet Weather
                                    Fecal Coliform Concentrations, Wells Street (CSO Area)
                                        & Brown Deer Road (Separate Drainage Area)
                                             Milwaukee  River, Milwaukee, WI

-------
   5400
                 SINGLE PURPOSE    STORAGE - TREATMENT
                                 ONLY
                 MULTIPLE PURPOSE   PORTION OP  STORAGE
                 TREATMENT   COSTS ASSiGNEO TO  OTHER
                 PURPOSES
                 SINGLE PURPOSE    STORAGE-TR ETATMENT
                 AND BEST MANAGEMENT PRACTICES
                 SINGLE PURPOSE  .  STORAGE - THEATMtNT
                 ONLY  RESULTS  FOR COMBINED
                 SEWERED  AREAS
             U.S.  URBAN POPULATION    149 XIC
             U,S,  DEVELOPED URBAN AhEA   15.6 X 10 ac
                                                                                 100
                                 %   BOD  REMOVAL , R|
Figure   8.    Single  Purpose  and Multiple Purpose Stormwater  Pollution
               Control Costs for US
                                            395

-------
     Additional national cost reductions
were shown by the multi-purpose coordin-
ated use of wet and dry weather flow treat-
ment facilities, and storm flow storage
facilities used as dual sedimentation-
treatment processes  (see Curve B, Figure
8).  Within certain control levels best
management practices, e.g., street clean-
ing and sewer flushing, could further
reduce control costs (Curve C, Figure 8).
When compared to prior studies the major
reduction in the national figure for
stormwater control is attributable to
discounting storm sewer line construction
(at $84 billion) and flood control  (at
$73 billion).

Solution Methodology

     The second area under Problem
Definition, "Solution Methodology"
naturally followed initial "Character-
ization" for providing a uniform and
necessary background for the user
community.

More Accurate Problem Assessment

     Considering the limitations in the
presently available data base, the first
and most fundamental approach should be
a more accurate assessment of the problem.
Ideally, this should involve acquiring
data on a city-wide basis for both DWF
and wet-weather flow (WWF) including
upstream-downstream pollutants mass
balances and the effects of the waste
loads on the receiving waters.

Cost-Effective Approach

     Integrated with a more accurate
assessment is the consideration of cost-
effective approaches to WWF pollution
control.

     Present abatement alternatives
exhibit an extraordinary range of cost-
effectiveness.   For example, cost-
effectiveness in terms of dollars/lb
of pollutant removed for an alternative
such as storage plus primary treatment,
varies over a range of 75:1, depending
on such factors as location and land
costs, type and condition of sewerage
systems, pollution loads, and type of
storage configuration.   This very high
cost-effectiveness variability
demonstrates the irrationality of any
attempt  to prescribe uniform national
standards for the technology of total
urban  load abatement as opposed to
requiring site-specific studies.

     There is an excellent opportunity
to bring down the high costs implied for
storm  flow control.   The most cost-
effective solution methodology must
thoroughly consider:

      (1) Wet-weather pollution impacts in
lieu of  blindly  upgrading existing
municipal plants.

      (2) Structural  versus land management
and non-structural techniques.  Studies
have indicated that  it may be cheaper
to remove pollutants  from the source by
such measures as street,  catch basin, and
sewer  cleaning than by eliminating them
by downstream treatment.   Certain land
use, zoning,  and construction site erosion
control practices  are other ways of
alleviating the  solids burden to the
receiving stream or treatment plant;

      (3) Integrating  dry  and wet-weather
flow systems  to  make  maximum use of the
existing sewerage  system  during wet
conditions and maximum use of wet-weather
control/treatment  facilities during dry
weather; and

      (4) The  segment  or bend on the per-
cent pollutant control versus cost curve
(see Figure 8 for  example)  where cost
differences increase  at much higher rates
than pollutant control increases.  This
phenomenon is  caused  by the need to size
storage-treatment  facilities at dispro-
portionately  greater  capacities for the
less frequent storm events required for
higher pollutant controls.

     Until two important  philosophies are
allowed  to prevail, the high cost impli-
cations  for wet-weather pollution abate-
ment will continue.   First,  flood and
erosion control  technology must be
integrated with  pollution control tech-
nology so that the retention and drainage
facilities required  for flood and erosion
control  can be simultaneously designed
for integrated dual-benefits of pollution
control.  Second,  if  land management
and non-structural techniques are maxi-
mized  and integrated, there will be less
to pay for the extraction of pollutants
from storm flows in  the potentially more
costly downstream plants.
                                           396

-------
 Example Solution Methodology

     It is worthwhile to discuss a
 hypothetical example of a cost-effective
 solution methodology.  Figure 9 represents
 one such approach.   This case is for D.O.
 Actual studies should include other para-
 meters and should represent at least one
 year of continuous data (at a minimum rain-
 fall data) .  By this analysis a truer cost-
 effectiveness comparison can be made based
 on total time of receiving water impacts
 and associated abatement costs.  For
 example, if a 5 mg/1 D.O.  is desired in
 the receiving water 75% of the time as a
 standard, an advanced form of wet-weather
 treatment or primary wet-weather treatment
 integrated with land management is
 required.  The latter is the most cost-
 effective at $3 million.  This or similar
.methodologies (157, Chapter VII) can help
 set cost-effective standards as well as
 select alternatives.

     There is a critical lacking of mean-
 ingful water quality standards —
 especially for storm flow transient
 effects.  This limitation forces the use
 of  (1) existing criteria not well backed
 up by ecological receiving water effects,
 or  (2) arbitrary percent control of
 combined sewer overflow or storm discharges.
 A critical need exists for the technology
 development sectors to join together with
 the receiving water ecology sectors to
 define and establish wet-weather receiving
 water effects.  It is felt that the
 present state-of-the-art is advanced
 far enough to generate approximate land
 runoff pollutant loadings from different
 control options and subsequent receiving
 water pollutant concentration.  By filling
 the important gap of an adequate set of
 receiving water quality standards, the
 necessary foundation tools will be
 available for a true cost-effective
 solution methodology.

 Administrative Problems

     There are basic problems in
 administration that must be overcome.  In
 the United States autonomous Federal and
 local agencies and professions involved
 in flood and erosion control, pollution
 control, and land management and environ-
 mental planning must be integrated at
 both the planning and operation levels.
Multi-agency grant  coverage must be
adequate to stimulate  such an approach.
For example, EPA would have to join with
the Army Corp of Engineers, Soil
Conservation Service,  Department of
Transportation, and perhaps other
Federal agencies as well  as departments
of pollution control,  sanitation, planning
and flood control at the  local level.
EPA1s present policy of funding construction
will also need expansion  to cover cost-
effective land management and non-struc-
tural techniques promulgated  by its
planning grant approach.

Solution Methodology:  Products

     Highlighted solution methodology
products are the often referenced eight
city studies  (41, 51,  53, 54,  49, 60,  65,
83) which involved  an  economic comparison
of pollution control alternatives for
both dry and wet weather  flow.

     The state-of-the-art (SOTA)  text  on
urban stormwater management and technology
(102) is considered an excellent program
milestone and guide for planners and
engineers.  It organizes  and  presents
more than 100 completed Program projects
as of December 1973.   The text is presently
being updated and will include comprehen-
sive guidelines for total city-wide, wet-
weather pollution control planning and
countermeasure selection  (P-5).   Other
in-house Program documents (111,  R-6a,
R-6b, R-6c, R-6d, R-6e, R-6f,  R-6g,  R-6h,
R-6i) must also be  included in this
category.

     A film is available  covering the
entire Program, and in particular full-
scale control technologies (R-7).
Program seminar proceedings (6,  40,  96)
with themes of "design, operation,  and
costs" have been published.   Urban
runoff seminar proceedings for 208 plan-
ning agencies  (140a) are  also available.
Separate engineering manuals  are
available for urban storm flowrate and
volume determination (140, 123),  storm
sewer design  (71),  and conducting urban
stormwater pollution and  control studies
(145).  SOTAs on storm flow measuring
(130) and sampling  (87, 133)  have also
been published.  All these documents are
valuable references for the planning and
implementing of urban  stormwater studies
for PL 92-500, 201, Step  1, and 208 grants.
                                           397

-------
   100 -i^-.
u
CO
CO
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o
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O
 CN
I
U
    75-
     WET-II (75% Rem) OR
V (~WET-I (PRIM)/LM
 \^     (75% Rem)
\\         I

     I  (25% REM.)
                             D.O. (mg/l)
CONTROL
ALTERNATIVES
EXISTING
TERTIARY
WET-I (PRIMARY)
WET-II (ADV)
WET-I/LAND MGMT.
% BOD REMOVAL
DRY WEATHER
85
95
85
85
85
WET WEATHER
0
0
25
75
75
COST
($xl06)
—
6
1
6
3
                 Figure 9.  Example Solution Methodology
                               398

-------
     In the area of "unit cost  information"
a manual  (156) is being published which
contains  summary unit cost  graphs on
construction and operation  of the basic
urban stormwater storage and treatment
devices.  An example on storage facility
construction costs is presented in Figure
10.  Additional cost information and
equations can be obtained from  the above-
mentioned text on urban stormwater manage-
ment and  technology  (102),  the  SWMM user's
manual (116), the nationwide stormwater
assessment document  (157) ,  and  the
manual for preliminary  (level I)  storm-
water control screening  (153).

     Other manuals are available for
deicing pollution  (100, 104) and erosion
control  (68, 70, 90, 92, 168, 169).   The
SOTA document on size and settling velocity
characteristics of particles in storm and
sanitary  water  (115) is important because
it offers information for physical treat-
ability of suspended solids and anticipated
settlement in receiving waters.  More
information  of this nature, along with
the availability of pollutants  with the
suspended solids, is needed.  These,
along with the aforementioned solution
methodology  documents, are  or should be
serving for  201 and 208 studies.

     Looking to the near future a city-
wide demonstration  (P-15) of a  multi-
faceted approach methodology is nearing
completion in Rochester, NY.  The product
from this study will serve  as an example
for other cities.

     There is also an endeavor  to study
direct receiving water impacts  along with
verification of a water quality model.
This task will serve as an  important
demonstration by lending credence to the
implications of storm flow  impacts.
The previously discussed Milwaukee project
(P-68) covers this objective.   Other
demonstration sites are being sought by
the Program.  Receiving water impacts have
been included in an ongoing project in
Lancaster, PA (P-4) and additional non-
EPA funds to conduct a receiving water
impact analysis for the ongoing Rochester
project (P-15) have been secured.

         USER ASSISTANCE TOOLS

     The  User Assistance Tools  are divided
into "Instrumentation" and  "Simulation
Models."
Instrumentation

     The qualitative  and  quantitative
measurement of storm  overflows  is essen-
tial for planning, process  design,
control, evaluation,  and  enforcement.
"Urban intelligence systems"  require real-
time data from rapid  remote sensors  in
order to achieve remote control of a
sewerage network.  Sampling devices  do not
provide representative aliquots,  and in-
line measurement of suspended solids and
organics is needed.   Conventional rate-
of-flow meters have been  developed mainly
for relatively steady-state irrigational
streams and sanitary  flows  and  not for the
highly varying surges encountered in storm
and combined sewers.  A schematic of
instrumentation development by  the Program
is shown on Figure 11.

     The electromagnetic  (P-45),  ultra-
sound  (150), and passive  sound  (139)
flowmeters have been  developed  to overcome
these adverse storm flow  conditions  (which
require dual pressure-gravity measurement
of unsteady flows by  non-intrusive
instrumentation).  Further  demonstration
of the electromagnetic and  passive sound
flowmeters will take  place  shortly.
Passive sound instruments offer the
additional benefit of extremely low  power
requirements rendering them amenable to
installation at remote overflow locations
(where power may not  exist) and integration
into city-wide, in-sewer, sensing, and
control systems.  A prototype sampler for
capturing representative  solids in storm
flow, and overcoming  storm  flow adversities,
has been developed and compared with
conventional samplers.  Favorable results
have been obtained and a  design manual
(135) is available.   Demonstration of two
previously developed  instantaneous,  in
situ monitoring devices for suspended
solids  (113)  (based on the  optical
principle of suspended solids depolarizing
polarized light) and  TOC  (126)  were
successfully conducted.

     Separate SOTA reports  for  flow
measurement (130) and sampling  (87,  133)
have been mentioned under problem
definition.  A SOTA on organic  analyzers
(110) is also available.  Because storm
flow conditions are extremely adverse, the
manuals and instruments developed for the
Program in this area  are  useful for  the
monitoring of all types of  waste flows.
                                            399

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                             STORAGE CAPACITY - MILLION GALLONS
              Figure 10.  Construction Cost Example: Storage Facilities
                                     400

-------
                       PRE-FY76
                                                                    FY76
                                                                                      FUTURE
RAIN
QUAN
(FLOW  MEAS)
                    METER DEV
                 • DUAL  GRAVITY-
                   PRESS
                 .NON-INTRUSIVE
                 •UNSTEADY STATE
                   (EM,  SOUND,
                  PASSIVE SOUND)
                                                                       RADAR
                                                                      (REMOTE
                                                                     WARNING)
                                                                     FULL-SCALE
                                                                     TEST LOOP
                                                                   • REAL SEWAGE
QUAL
(SAMPLING,
    IN-SITU)
SOA/
ASSESS
SAMPLING



DEV/DEM SCS
• IN SITU SS
•IN SITU TOC
•SAMPLER


CONT. DEM. SCS
• IN SITU TOC
•SAMPLER

CONTROL
• FABREDAM
• POSITIVE CONTROL GATES
•FLUIDIC
• TELEMETRY (REMOTE
      SENSING/CONTROL)
                                                                                      • OPTIMIZE
                                                                                        DIVERSION
                                                                                        GATES(FOR
                                                                                        IN-LINE)
                           Figure  11.   Instrumentation for Total  System Management

-------
     Remote raingaging by radar is being
considered for an automated combined
sewer flow routing project in San
Francisco (P-25).

Instrumentation:  Products

     An instrumentation product summary
is listed on Table 3.
                          TABLE 3 - INSTRUMENTATION:  PRODUCTS
              Flow Measuring Devices Development

                   - Electromagnetic (open-channel and press  flow)  (P-45)
                   - Ultra-sound  (150)
                   - Passive sound  (139)

              Sampler Development (135)
              In situ suspended solids monitor development  (113)

              In situ TOC monitoring system development  (126)

              SOTA/Assessment reports

                   - Sampling (133)
                   - Flow measuring (130)
                   - Organics monitoring  (110)
Simultation Models

     Math models are needed to predict
complex dynamic responses to variable
and stochastic climatological phenomena.
Models have been subcategorized into
three groups: (1)  simplified for prelim-
inary planning,  (2)  detailed for planning
and design, and (3)  operational for
supervisory control (Figure 12).

     The Storm Water Management Model
(SWMM) provides a detailed simulation of
the quantity and quality of stormwater
during a specified precipitation event.
Its benefits for detailed planning and
design have been demonstrated and the
model is widely used.   However, for many
users it is too detailed; e.g., the 208
planning effort needs simplified proce-
dures to permit preliminary screening of
alternatives.  Consequently, current
Program thinking on urban water management
analysis in general, and SWMM in particu-
lar, involves four levels of evaluation
techniques ranging from simple to complex
procedures than can be worked together.
The major portions of all four levels have
been developed (Table 4).
Planning/Design Models

     Level I — The Level I procedure as
developed by the University of Florida
(153) was directly derived from the
previously mentioned nationwide cost assess-
ment project (157).  This assessment docu-
ment already contains data on land use;
drainage system types; runoff volumes and
pollutant quantities; costs and cost-
effective control strategies for the 248
Standard Metropolitan Statistical Areas
in the Country.  The information, also
itemized for States and EPA regions, can
be used in the early stages of problem
assessment, determining national cost
requirements and preliminary planning.

     In Level I, a "desktop" statistical
analysis procedure permits the user to
estimate the quantity and quality of urban
runoff in the combined, storm and unsewered
portions of each urban area in his juris-
diction.

     For example, under the University of
Florida approach, equations such as those
shown in Table 5 have been statistically
developed to estimate BOD  , SS, VS, P04 and
                                           402

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                                            PRE-FY76
                                                                                      FY76
                                                                                                          FUTURE
SIMPLIFIED
(PRE-PLAN)
DETAILED
(PLAN/DESIGN)
SIMPLIFIED
SWMM

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• CONTINUOUS



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(DETROIT, ST. PAUL, SEATTLE)


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(SAN FRANSCICO)


DEM. AUTOMATIC
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DISSEMINATION
SWMM
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T.T.
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SWMM
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MAN III


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                             Figure 12.   Simulation Models  for Total System Management

-------
                  TABLE 4 - LEVELS OF URBAN WATER MANAGEMENT ANALYSIS
          Preliminary:  Print out information  from Nationwide Assessment (157)
          Level I:      Desktop - no computer,  statistical analysis
              - UF Methodology  (153)
              - Hydroscience methodology  (R-8)
          Level II:
Simplified continuous simulation model
              - Simplified SWMM  (by M&E)  (148)

          Level III:    Refined continuous  simulation model

              - Continuous SWMM  (P-53)
              - Storm (R-9, R-10)
          Level IV:
Sophisticated single event simulation model
              - Detailed SWMM  (116, 125)
N loads as a function of land use, type of
sewer system, precipitation, population
density, and street sweeping frequency.
The a and (3 terms represent normalized
loading factors in Ib/ac-in., tabularized
as functions of land use, i and pollutant
type, j, for separate and combined areas,
respectively.  These factors were derived
from a statistical review of available
stormwater pollutant loading and
effluent concentration data (157).

     Similarly, Table 6 gives equations
for analyzing runoff for both stormwater
flow prediction and DWF prediction.  Here
again the equations were based on a
statistical analysis of available data.

     A generalized method for evaluating
the optimal mix of storage and treatment
and its associated costs has also been
developed.  Also, procedures for comparing
tertiary treatment with stormwater manage-
ment and possible savings from integrated
management of domestic wastewater, storm-
water quality and stormwater quantity from
combined and separate drainage areas, are
available.

     The Hydroscience approach offers
another procedure for assessing urban
pollutant sources, loadings, and
control.  Both approaches, available in
the form of user's manuals, are being
published (153, R-8).
                            Level II — Level  II  involves a
                       simplified continuous model  for planning
                       and preliminary sizing  of  facilities.  The
                       model can run on daily  time  steps to screen
                       the entire history of rainfall records or
                       hourly time steps to screen  the worst two
                       years.  It is inexpensive  to set up and
                       use, flexible enough to be applicable to
                       a variety of system configurations, and
                       accurate even though only  very moderate
                       expenditures are made for  data collection
                       and preparation.  It is especially valuable
                       in sizing storage facilities based on storm
                       return periods and available in-line
                       capacity.  A user's manual is available
                       (148).

                            Level III — Level III  involves a more
                       refined continuous model approach  (e.g.,
                       STORM, continuous SWMM) which in addition
                       to Level II provides for flow time routing
                       and continuous receiving water impact
                       analyses.  The number of program statements
                       involved here is in the order of a few
                       thousand as compared to a  few hundred for
                       the Level II effort.  A user's manual
                       and program for STORM is available (R-9,
                       R-10).  The continuous  SWMM  user's
                       manual is in preparation.

                            Level IV — The aforementioned three
                       levels essentially represent various
                       degrees of planning efforts  and the
                       models involved are typified by relatively
                       large time steps  (hours) and long  simu-
                       lation times  (months and years).   Data
                       requirements are kept to a minimum and
                       their mathematical complexity is  low.
                                           404

-------
                 Table  5.   Pollutant Analysis
     The following equations may be used to predict annual  average
loading rates as a function of land use, precipitation and  population
density.
Separate Areas:   M  •= a(i,j)  •  P
                                                  Ib
Combined Areas:

         where
                               P '  f2(PDd)
acre-yr
   Ib
acre-yr
                       M  =» pounds of pollutant J  generated per acre  of
                            land use i per year,
                       P  = annual precipitation,  inches per year,
                      PD  = developed population density,  persons  per acre,
                     a,B    factors given in table below,
                       Y    street sweeping effectiveness factor,  and
                    PD )    population density function.
Land Uses:  i   1  Residential
            i   2  Commercial
            i   3  Industrial
            i = 4  Other Developed, e.g., parks, cemeteries,  schools
                        (assume PD.
                                      0)
Pollutants:  j
            j
            j
            j
            j
Population.
                1  BOD ,  Total
                2  Suspended Solids (SS)
                3  Volatile Solids, Total (VS)
                4  Total PO  (as PO )
                5  Total N
                      i   2,3
                      i - 4
                                2.
                                    j
                                    d
                                         0.142 + 0.218
                                         1.0
                                       = 0.142
                                                         PD
                                                            0.54
Factors a and 8 for Equations:  Separate factors, d, and combined factors,
            ft, have units Ib/acre-in.  To convert to kg/ha-cm,  multiply
            by 0.442.

                                   Pollutant, j

              Land Use,  i    1.  BOD     2. SS   3. VS   4. P04    5. N
             1.  Residential    0.799
  Separate   2.  Commercial     3.20
  Areas,   20 days
                                         s
                                   405

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                                TABLE 6 -  RUNOFF ANALYSIS
              Stormwater Flow Prediction

                           AR =  (0.15 + 0.75  1/100  P -  5.234 (DS)

                           AR = Annual Runoff,  in/yr
                                                    0.5957
where
              where
                            I = 9.6 PD
                                        (0.573-0.0391 log  PD )
              where
              I = Imperviousness, Percent and

            PD  = Population Density in Developed Portion  of  the
                  Urbanized Area, Persons/Acre

              P = Annual Precipitation, in/yr and

             DS = 0.25-0.1875  (I/WO) 0£ I _< 100

             DS = Depression Storage, in.   (0.005 <  DS  < 0.30)
              Dry Weather Flow Prediction
                          DWF =1.34 PD,
                                       a
              where       DWF = Annual Dry-Weather Flow,  in/yr,  and

                          PD, = Developed Population Density,  Persons/Acre
                            a
     Design models on the other hand are
oriented toward the detailed simulation
of a single storm event.  They provide a
complete description of flow and pollutant
routing from the point of rainfall through
the entire urban runoff system and into
the receiving waters.  Such models may be
used for predictions of flows and
concentrations anywhere in the rainfall-
runoff system and can illustrate the
detailed and exact manner in which abate-
ment procedures or design options affect
them.  At such, these models are a highly
useful tool for determining least-cost
abatement procedures for both quantity
and quality problems in urban areas.
They are typified by short time steps
(minutes)  and short simulation times
(hours).   Data requirements are usually
very extensive.  The EPA SWMM is such a
model.  SWMM user's manuals and other
pertinent references that were revised
at a critical junctures are available
(42, 43,  44, 45, 116, 120).  Eventually
is is hoped than SWMM can be expanded
into an Urban Water Management Model which
integrates both dry- and wet-weather flow
analyses including sludge handling capa-
bilities.   This is emphasized in the
Program report on future direction of the
modeling development (136).
                                 Operational Models

                                      Operational models are used to
                                 produce actual control decisions during
                                 a storm event.  Rainfall is entered
                                 from telemetered stations and the model is
                                 used to predict system responses a short
                                 time into the future.  Various control
                                 options may then be employed, e.g., in-
                                 system storage, diversions, regulator
                                 settings.  The Program has demonstrated
                                 supervisory control models in Detroit
                                 (118), Minneapolis-St. Paul (19), and
                                 Seattle (29, 98); and has recently
                                 started on a project in San Francisco
                                 (P-25) taking advantage of a $100 million
                                 construction grant, to develop a fully
                                 automated operational model which includes
                                 rainfall prediction.

                                 Simulation Models:  Products

                                      Other simulation model products
                                 include demonstration of a dissemination
                                 and user assistance capability  (122) and
                                 development of a short course and course
                                 manual  (T25, P-51) for stormwater manage-
                                 ment model application.  Of particular
                                 note is the SOTA assessment document on
                                 18 available mathematical models for
                                 storm and combined sewer management  (141).
                                           406

-------
                        TABLE 7 - SIMULATION MODELS:   PRODUCTS
   Development of a computer model  (SWMM)  for  storm water management (42, 43, 44, 45)

   Updated and refined user's manual modifying and improving SWMM (116).

   Demonstration of a stormwater management  model dissemination and user assistance
   capability (122) .

   User's manual for "desktop calculation" procedure for preliminary stormwater
   management planning  (153) .

   User's manual for simplified model  application for preliminary stormwater
   management planning  (148).

   Course manual and seminar for stormwater  management model application (125).

   Assessment of mathematical models for  storm and combined sewer management  (141).

   Refine and augment the capabilities of SWMM and develop decision-making
   capabilities (120).

   Evaluation of available runoff prediction methods for storm flowrate and volume
   determination (140).
The document presents a summary of the
objectives, advantages and limitations  of
each model along with a side-by-side
comparison to aid in assessing the
applicability of a model for a particular
purpose.  Table 7 summarizes simulation
model products.

         MANAGEMENT ALTERNATIVES

    Wet weather flow control can be
assumed to involve aspects as follows.
First there is the choice as to where to
attack the problem: at the source  (e.g.,
the street, gutters, and catchment areas)
by land management, in the collection
system, or off-line by storage.  Pollutants
can be removed by treatment and by employ-
ing complex or integrated systems which
combine variations of control and treatment
including the dual-use of dry-weather
facilities.  Second, there is the choice of
how much control or degree of treatment
to introduce.  Thirdly, there is the impact
assessment, public exposure, and priority
ranking with other needs.  The proper
management alternatives can only be made
after a cost-effective analysis involving
goals; values; and hydrologic-physical
system evaluations, generally assisted  by
mathematical model simulations, pilot-
scale trials, and new technology transfer.
Land Management

     Land Management includes all measures
for reducing urban and construction site
stormwater runoff and pollutants before
they enter the downstream drainage system
(Figure 13).  On-site measures include
structural, semi-structural and non-
structural techniques that affect both
the quantity and quality of runoff.

     Careful consideration must be given
to land use planning since urbanization
accelerates hydrograph and pollutograph
peaks and total loads by creating imper-
vious surfaces for pollutants and water
to run off from.  This causes excessive
water pollution, erosion, sedimentation
and flooding.  Discreet selection of  land
management techniques can reduce drainage
and other downstream control costs
associated with these problems.

     Until two important philosophies
prevail, the high cost implications
for wet-weather pollution abatement will
continue.  Established flood and erosion
control technology must be integrated with
pollution control technology so that  the
retention and drainage facilities and
other non-structural management techniques
required for flood and erosion control can
be simultaneously designed for pollution
control.
                                          407

-------
                                                            LAND MANAGEMENT
o
oo
STRUCTURAL/ SUMI-STRUCTURALJ-


ON-SITE
(UPSTREAM)
STORAGE
CONSTRUCTION (HYDROLOGIC MODIFICATION) CONTROL 	 j NON- STRUCTURAL
Erosion/Sedimentation (Construction )
Flood
Pollution

o RETENTION
Basins/Ponds
Recharging Ponds
o DETENTION
Basins /Ponds
Dual Use
Rooftop
Parking Lot/Plaza
Recreational Facilities
Aesthetics

POROUS PAVEMENT


o SWALES
OVERLAND o DIVERSION STRUCTURES
FLOW Ditches
MODIFICATION Chutes
Flumes

SOLIDS
SEPARATION
o SEDIMENT BASINS
o FINE SEDIMENT
REMOVAL SYSTEMS
Tube Settler
Upflow Filter
Rotating Disc Screen
o SWIRL DEVICE








SURFACE
SANITATION

o ANTI LITTER
o STREET CLEANING
o STREET FLUSHING
o AIR POLLUTION CONTROL

CHEMICAL
USE
CONTROL
o LAWN CHEMICALS
o INDUSTRIAL SPILLAGE
0 GASOLINE STATIONS
o LEAD IN GASOLINE
o HIGHWAY DEICING

URBAN
DEVELOPMENT
RESOURCE
PLANNING

USE OF NATU-
RAL DRAINAGE
EROSION
SEDIMENTATION
CONTROL
o COMPUTER SIMULATION
Land Use
Population Density
Control Options

o MARSH TREATMENT
o CROPPING
Seeding
Sodding
o SOIL CONSERVATION
Mulching
Chemical Soil
Stabilization
Berming
                                                       Figure 13.   Land  Management

-------
Structural/Semi-Structural Control

    Structural and semi-structural  control
measures require physical modifications in
a construction or urbanizing area and
includes such techniques as: on-site
storage, porous pavement, overland flow
modifications and solids separation.

    Qn-Site  (Upstream) Storage — On-site
or upstream storage refers to detention
(short term) or retention  (long term)  of
runoff prior to its entry into a drainage
system.  Simple ponding techniques are
utilized on open areas where stormwater
can be accumulated without damage or
interference to essential activities.
Oftentimes, on-site storage does or  can
be designed to provide for the dual  or
multi-benefits of aesthetics, recreation,
recharge, irrigation, or other uses.   For
example, in Long Island, NY, groundwater
supplies are being replenished by retention-
recharge.  The dual benefit of recharging
is stressed because urbanization depletes
groundwater supplies; however, potential
groundwater pollution must also be
considered.

    Successful variations of detention
that take advantage of facilities
primarily used for other purposes are
ponding on parking lots, plazas,
recreation and park areas; and ponding
on roof tops.  The fundamental approach
is the same as for other forms of detention
but low cost is implied.  Dual purpose
basins used for recreation and athletics
when dry are also employed.

    Surface ponding is the most common
form of detention being used by developers.
Apparent economic benefits of surface
ponding for flood protection are derived
from the savings over a conventional
sewer project.  Several surface ponding
sites are listed in Table 8 where a  cost
comparison is made between a drainage
system using surface ponds to decrease
peak flows and a conventional storm  sewer
system.  It is important to note that
pollution and erosion control benefits
of the basins are not included in this
comparison.
     Porous Pavement  —  Another approach
to stormwater management is the use of an
open graded asphalt-concrete pavement
which under pilot  testing has allowed
over 70 in./hr. of stormwater to flow
through  (Figure 14)  (64).   Stability,
durability, and freeze-thaw tests have
been positive and  it  is  comparable in
cost to conventional  pavement.   Long-term
tests are still required to evaluate
clogging resistance and  the quality of
water that filters through.  If the soil
porosity under the pavement allows free
drainage there will be no water residue;
however, the coarse sub-base and porous
nature of the pavement can serve for
ponding capacity if storm quantities exceed
soil infiltration.  A 4-inch pavement and
6-inch base could  store  2.4 in.  of runoff
volume in its voids.  The  proven use of
porous pavement can be an  important tool
in preserving natural drainage  and
decreasing downstream drainage  and
pollution control  facility requirements.
As a result of Program studies  a feasibility
report (64) is available.   The  Program is
currently evaluating  a porous pavement
parking lot (P-16) and results  of this
study will be available  next year.
                   AGGREGATE GRADED fO
                    A WATER FLOW OF
EXCEEDED
THE
MINIMUM MAR-
SHALL STABILITY
CRITERION
FOR \
MEDIUM TRAFFIC \
USES
AEROBIC AC
*&&
|fig|
riviTY UGHS
UNDER PAVEMENT — IvS^
NOT IMPAIRED P5ȣ
DURABILITY TEST /
INDICATED THAT /
HEIGHTENED EX-
POSURE TO AIR OR
WATER DID NOT PRO-
DUCE ASPHALT
HARDENING
/' •'''•'•"'•',
5.5*BY WT. OF
85-100 PENETRATION
ASPHALT CEMENT
BINDER
JBfek ,/ ••''•'•

ffl|?
?"^*J: ' ' - .;:''.V
'>%£$ SUBJECTED TO 2S5
*-~\ • FREEZE-THAW CY-
N^ CLES WITH NO ;
CHANGES IN PHYS-
ICAL DIMENSIONS.
MARSHALL STABILITY'
VALUES OR FLOW
RATES..*
      Figure 14 - Porous Asphaltic-
        Concrete Features

     Overland Flow Modification  — Another
form of structural and  semi-structural
control is overland flow modification
including swales and diversion structures
(e.g., ditches, chutes, flumes).  These
modifications are usually  of  lower cost
than subterranean sewer construction and
importantly allow vegetative  cover and soil
infiltration to reduce  runoff and pollutant
loadings.
                                           409

-------
TABLE 8 - COST COMPARISON BETWEEN
AND CONVENTIONAL SEWER
Site Description
Earth City,
Missouri
Consolidated
Freightways ,
St. Louis,
Missouri
Ft. Campbell,
Kentucky
Indian Lakes
Estates, Blooming-
ton, Illinois
A planned community in-
cluding permanent rec-
reational lakes with
additional capacity for
storm flow
A trucking terminal using
its parking lots to de-
tain storm flows
A military installation
using ponds to decrease
the required drainage
pipe sizes
A residential development
using ponds and an
existing small diameter
drain
SURFACE PONDING TECHNIQUES
INSTALLATION (R-8)
Cost Estimate, $
With Surface
Ponding
2,000,000
115,000
2,000,000
200,000
With Conventional
Sewers
5,000,000
150,000
3,370,000
600,000
     Solids Separation — Sediment basins
trap and store sediment from erodible areas
in order to conserve land and prevent
excessive siltation downstream.  If designed
properly, these basins can remain after
construction for on-site storage.  A
project  (P-46) is evaluating the efficiency
of sediment basins.

     Because a significant portion of the
eroded solids may be colloidal or unsettle-
able and therefore cannot be treated in
conventional sedimentation basins, special
devices for fine-particle removal are
required.  An ongoing project  (P-73)
has developed a SOTA (163) on methods for
fine-particle removal and is now under-
taking the evaluation of three solids
separation devices (i.e., tube settler,
up-flow filter, and rotating disc screen).

     The swirl concentrator has been
developed for erosion control  (P-3, 99) to
remove settleable solids at much higher
rates than sedimentation.  A prototype
device is presently being evaluated at a
construction site  (P-74).
Non-S tructural

     Non-structural control measures
involve surface sanitation, chemical use
control, urban development resource
planning, use of natural drainage, and
certain erosion/sedimentation control
practices  (Figure 13).

     Surface Sanitation — Maintaining
and cleaning the urban area can have a
significant impact on the quantity of
pollutants washed off by stormwater.
Cleanliness starts with reduction of
litter and debris at  the neighborhood
level.  Both street repair and street
sweeping can further minimize the pollutants
washed off.  It has been estimated that
street sweeping costs per ton of solids
removed are about half the costs for
solids removed via the sewerage system.

     The effectiveness of street sweeping
operations with respect to stormwater
pollution has been analyzed by EPA  (73,
88, 128, 157, P-49).  It was found that
a great portion of the overall pollution
potential  is associated with the fine
solids fraction of the street surface
                                            410

-------
            TABLE 9 - ADVANCED* STREET CLEANER POLLUTANT RECOVERY PERCENTAGE
                           Parameter
                       Dry Weight Solids
                       Volatile Solids
                       BOD
                       COD
                       Total PO4-P
                       Heavy Metals
% Recovery

  93
  80
  67
  84
  85
  83-98
                  *Broom and Vacuum Combination
contaminants and that only 50 percent of
the dry weight solids are picked up by
conventional broom sweepers  (73) as compared
to 93 percent removal by more advanced
techniques  (128) (Table 9).

    Cities clean their streets for aesthe-
tic reasons, removing the larger particles
and brushing aside the fines.  Conventional
sweepers are utilized and satisfy the
aesthetics problem.  More advanced street
cleaning procedures such as  a combination
of sweeping and vacuuming would not only
satisfy the aesthetics problem but would
also attack the source of stormwater
related pollution problems by removing
the finer or more pollutant  prone range
of particles.

    Further verification of the benefits
of street cleaning will be carried out in
an ongoing grant (p-25).  Also, a desktop
analysis comparing the cost-effectiveness
of street cleaning and sewer flushing
with downstream treatment methods is near-
ing completion under another study  (P-73) .
Flushing of streets can be used to remove
street contaminants effectively; however,
it may necessitate more frequent catch
basins and sewer cleaning.   Street
cleaning is estimated to cost $3 to $13/
curb mi or about $0.75/ac.

    Air pollution abatement plans must
also consider water pollution reduction
benefits from decreased fall out.

    Chemical Use Control — One of the
most overlooked measures for reducing
the pollution potential from neighborhood
areas is the reduction in the indiscrim-
inate use of chemicals such  as fertilizers
and pesticides, and the mishandling of
other materials such as oil, gasoline,
and highway deicing chemicals.  Aside
from air pollution control, de-leaded
gasoline also results in water pollution
control.

     The progression of studies in deicing
chemical control, and resulting reports,  is
depicted in Figure 15.  The Program's
motivation from the start has been to
determine the extent of environmental
damages and costs associated with the use
of chemical deicers so that the economic
validity of alternative approaches could
be assessed.

     Until the Program's assessment  of  the
problem in 1971  (67) there had been  only
limited research on highway deicing  effects.
Inquiries concerning this work indicated
such an increased public awareness of the
salt problems, that it seemed appropriate
to firm up recommendations for alternatives
to snow and ice control.  A search was
conducted  (76) to define alternatives.
The need for an accurate economic impact
analysis of using deicing salt, and  a
requirement to identify a substance  which
can be applied to pavement to reduce ice
adhesion was indicated.  These two needs
became projects which have recently  been
completed  (138, 152).  Hydrophobic
substances have been identified and  are
being investigated, and even though
material and application costs appear
greater than for salt  (0.20-0.25/yd  versus
$0.03/yd2), when considering total damage
to the environment  ($3 billion annually.
including paved area, highway structures
and vehicles) the costs are acceptable.
                                           411

-------
                         ASSESSMENT OF PROBLEM (67)
                       Rept:   Environmental Impact of
                           Highway  Deicing 6/71
                        EVALUATION OF APPROACHES (76)
                    Rept:   A Search:   New Technology for
                     Pavement Snow &  Ice Control 12/72
                               SOTA REVIEW (86,R-11)
                     Rept:   Water Pollution and  Associated
                      Effects  from Street Salting 5/73
                       —  ATTEMPTS  AT A SOLUTION 	
                        MANUALS OF PRACTICE (100,104)
Rept:  Manual for Deicing Chemicals
   Storage and Handling 7/74
     Rept:   Manual for Deicing Chemicals
       Application Practices 12/74  	
                 ECONOMIC ANALYSIS OF COSTS OF DEICING (138)
                     Rept:   An Economic Analysis of the
               Environmental Impact of Highway Deicing 5/76
ALTERNATIVE MATERIAL DEVELOPMENT (152)
Rept: Dev. Hydrophobic Substance to
Mitigate Pavement Ice Adhesion 10/76
   (OPTIMIZE HYDROPHOBIC SUBSTANCE (P-70)|
--^Ongoing Study:   Washington          [
   jState_ University 9/77               J
   Figure 15.  Deicing Chemical Control (Land Management/Non-Structural)
                                     412

-------
    After the 1973 assessment of  the
problem  (86, R-ll) , the Program recognized
that it was not practical to ban salt
since the "bare pavement" philosophy
was very popular and considered by most
highway authorities as the safest  way
for ice and snow removal.  The major
problems were identified with careless
salt storage practices and over-application
on highways, consequently, a 1974  project
resulted in manuals of practice for
improvement in these areas.  These manuals
(100, 104) were recognized as highly
significant by the user community.  To date,
over 7000 copies have been distributed.

    Urban Development Resource Planning  —
The goal of urban development resource
planning is to develop a microscopic
management concept to prevent the
problems resulting from shortsighted
urbanization plans.  As previously dis-
cussed, the planner must be aware  of total-
ly integrating planned urban hydrology
with erosion-sedimentation and pollution
control.  This new breed of planner has
to consider the new land development
planning variables of land usage,
population density and total wet and dry
runoff control as they integrate to effect
water pollution.  Computer simulation will
most likely play an important role.  A
simple land planning model has been
developed by G. K. Young  (140a, Chapter
I, pp 98-121) to encompass the pertinent
variables and the most effective control
options based upon receiving water
pollutant absorption capacity.  A  new
project is planned to perfect this area.

    Use of Natural Drainage — The
traditional urbanization process upsets
the existing water balance of a site by
replacing natural infiltration areas and
drainage with impervious areas.  The net
impact is increased runoff, decreased
infiltration to the groundwater and
increased flowrates, all contributing
to increased channel erosion and the
transport of surface pollutants to the
stream.  Promulgating the use of natural
drainage concepts will reduce drainage
costs; enhance aesthetics, groundwater
supplies, and flood protection; and
lower pollution.
     A project in Houston  (p-16)  focuses
on how a "natural drainage  system"  can
be integrated into a reuse  scheme for
recreation and aesthetics.   Good  land
use management will allow runoff  to
flow through low vegetated  swales and
into a network of wet-weather ponds,
strategically located  in areas  of porous
soils.  This sytem will cause some of
the runoff to seep into the ground and
retard the flow of water downstream,  thus
preventing floods caused by development
and enhancing pollution abatement.
The concept of considering  urban  runoff
as a benefit as opposed to  a wastewater,
in a new community development, will  be
employed and evaluated.

     Another project in Wayzata,  MN (P-28)
is using marshland for stormwater treat-
ment.  After sufficient testing it has
been determined that controlled stormwater
retention in the marsh resulted in better
vegetative conditions  which in  turn
enhanced stormwater nutrient removal.
It was found that if the marshlands were
filled in by urbanization it would  have a
detrimental effect on  the nearby  lake.

     Erosion/Sedimentation  Control  (Non-
Structural) — Other nonstructural  soil
conservation practices such as  cropping
(seeding and sodding)  and the use of
mulch blankets, nettings, chemical  soil
stabilizers and berming may be  relatively
inexpensive.  Two ongoing projects  (P-72,
P-74) are evaluating many of these
low structural intensive management
practices for proposed erosion  control
manuals.

Integrated Benefits

     While the flood control benefits of
all the above land management control
measures are easy to see, the stormwater
pollution and erosion  control effects
are difficult to quantify.   But briefly
stated, detaining or retaining  flow
upstream offers the opportunity for flow
quiescence resulting in solids  separation.
It also decreases downstream drainage
velocities and discharges to streams
resulting in less overflow  pollution,
siltation and scour.   Aside from  causing
downstream erosion, this scouring can
also increase pollution loads in  the
scouring stream.
                                          413

-------
Erosion/Sediment Control:  Products

     By showing the genealogy of the
products through past milestone events
(Figure 16) the strategy which has guided
the Program in this category can be
demonstrated.  The original "Guidelines
for Erosion and Sediment Control Planning
and Implementation" (70) are still
applicable to communities initiating an
urban sediment control program.

     For erosion-sedimentation controls,
many agencies (e.g.. The Department of
Transportation and Soil Conservation
Service, and state and local departments)
and factors must be considered and
interrelated in product development and
technology implementation.  For example,
the Soil Conservation Service has  pub-
lished a document with the State of
Maryland entitled, "Standards and
Specifications for Soil Erosion and
Sediment Control in Developing Areas"
(R-12).  Other states are using this
document as a model ordinance.  Local laws
will have an important impact on any Best
Management Practices proposed by EPA.
Therefore, there must be close liaison
between all groups.

     A recently developed training program
consists of an instructor's manual (168),
a workbook (169), and 2762 slides with
integrated audio cassettes.  The program
is directed to the local land developer
and inspector, the excavation contractor,
and the job foreman.  It is designed to
directly support the Maryland "Standards
and Specifications for Erosion and
Sediment Control in Developing Areas."
As the state and local agencies move
toward setting standards for control on
non-point sources, the need for this type
of training program becomes urgent.

     Future Program plans include an
evaluation of various cities'  erosion
control programs.  This product will be
the foundation for National Standards and
Specifications for sediment and erosion
control in developing areas and with the
findings of the Urban Runoff Program will
lead to the National Best Management
Practice for this category.

       COLLECTION SYSTEM CONTROLS

     The next category, collection
system control  (Figure 17) pertains to
those management  alternatives concerned
With, wastewater interception and transport.
These alternatives  include sewer separation;
improved maintenance  and design of  catch
Basins, sewers, regulators and tide gates;
and remote flow monitoring and control.
The emphasis, with  the  exception of
sewer separation, is  on optimum utilization
of existing facilities  and fully automated
control.  Because added use of the  exist-
ing system is employed,  the concepts
generally involve cost-effective, low-
structurally intensive  control alternatives.
To accomplish this  an extensive and
dependable intelligence system is
necessary.

Catch Basins

     A project is assessing the value of
catch basins  (P-17, 174)  as they are
presently designed  and  maintained.  Opti-
mized basin configuration,  design and
maintenance for removing solids before
sewerage system entry have  also been
investigated.  Evaluations  showed that
a catch basin contains  approximately
0.18 Ib-BOD  or the equivalent of one
person's daily contribution.   The
utilization of catch  basins can either
contribute to the pollutional load  or
aid in reducing downstream  treatment
depending on their  design and maintenance.

Sewers

     Solids deposition  in lines has always
been a plague to effective  maintenance.
Recently, the significance  of such  loads
as a major contributor  to first flush
pollution has been  recognized (P-66; 140a,
Chapter II, pp 62-82).

     Work is being  conducted on new sewer
designs for low flow  solids carrying
velocity to alleviate sewer sedimentation
and resultant first flush and premature
bypassing  (P-50); and also  on sewer
designs for added storage (P-13,  165).
As a natural follow-up  to Program work
with a controlled test  loop (13,  14), a
project has just been initiated to
demonstrate periodic  sewer  flushing during
dry weather for first flush relief  (P-66).

     Polymers to  Increase Capacity  —
Research  (6, 11, P-6) has shown that
polymeric injection can increase flow
capacity as much  as 2.4 times (at a
constant head).   This method can be used
                                            414

-------
1
COMMUNITY (R-12)
GUIDEBOOK 3/70



'
DEMONSTRATION
PROJECTS
(89,90,91)
!
EXECUTI
SUMMAR

i


f
URBAN SOIL (68)
EROSION 5/70


GUIDELINES (70)
PLANNING
IMPLEMENTATION 8/72
,
VE (92)
Y 2/74



-


~>
INTER AND (167)
INTRA AGENCY
PROJECTS
jf^^"
DEMONSTRATION (90)
FOR
SPECIALISTS 6/74
]


\
« >
SUMMARY (167)
STATE
PROGRAMS 3/75
^
AUDIOVISUAL (168,169)
TRAINING PROGRAM 8/76


1
STANDARDS & (R-13)
SPECIFICATIONS
USDA-SCS 6/75
[REGIONAL  (p-72,73,74)'  i
I TECHNIQUES  6/77       i "**!
I ___________ .  I
                     TECHNICAL
                  EVALUATION 1/78
               	y	
               i     NATIONAL
               j    STANDARDS &
               SPECS. FOR  BMP 6/78
                                                  	URBAN RUNOFF PROJECTS
Figure 16. Erosion/Sedimentation Control:  Products
                          415

-------
            PRE-FY76
                                                                                          FY76
                                                                                                                         FUTURE
        SEPARATION
      < FEASIBILITY STUDY
 RUNOFF INLETS/
            CATCH  BASINS
   • EFFECTIVENESS
   • CLEANING
   • NEW DESIGN
 REGULATORS/  TIDE GATES

  • SOTA/MOP
  • DEVICE DEV/DEM.
     -FLUIDIC
     -FABRE  DAM
     -POSITIVE GATES
     -SWIRL/HELICAL
  • MOP TIDE GATES
            SEWERS
EXISTING
 • FLUSHING
 • POLYMER
 • I/I CONTROL
   -SOTA/MOP
   -INST/DETECTION
   -EVAL.  METHODOLOGY/
    UPDATE  MOP
   -SEALING 4 LINING

NEW (NON-STRUCTURAL)
 • I/I PREVENTION
   -INSPECTION
   -CONSTRUCTION  MATERIALS
   -CONSTRUCTION  TECHNIQUES
   -IMPREGNATION
 •NEW  DESIGN
  -CARRYING VEL.
  - ADDED STORAGE
DEM. SEWER
 FLUSHING
                                                                                     DEM.  SULFUR
                                                                                    IMPREGNATION
                                                                                    FOR  IMPROVED
                                                                                       STRENGTH
                                                                                    CATCH BASIN DEM.
                                                                                                                           DEM.  NEW
                                                                                                                         SEWER DESIGN
                                                                                                                       TT DESIGN MANUAL
                                                                                                                       ON SWIRL/HELICAL
                                   SWIRL/HELICAL
                                 DEM. COMPARISON
TIDE
GATE DEVICE DEV.
      FLOW ROUTING
•DEM. IN-LINE  STOR.
•SELECTIVE RELEASE
•REMOTE SENSING/CONTROL
• DEV. TOTAL AUTO./SEW-
  ERAGE SYS.  CONTROL
                                                 CONTINUATION
                                                 OF AUTO. SYS.
                                                 CONTROL  DEV.
                               DEM. CITY-WIDE SYSTEM
                                         Figure  17.   Collection System  Control

-------
as a short or long-term correction of
troublesome pollution-causing conditions
such as localized flooding and excessive
overflows.  Direct cost savings may be
realized by eliminating relief sewer
construction (6); however, additional
cost verification at the site is necessary.

    Infiltration/Inflow — The Program
SOTA  (27) and manual of practice  (MOP)
(28) on infiltration/inflow  (I/I) identi-
fied a significant problem which led to
fruitful countermeasure research and a
national emphasis on I/I control.  Program
developments have included detection
methodology and instrumentation  (27, 28,
10); preventive installation and construct-
ion techniques, new and improved materials
(.22, 27, 28, 52, 61, P-31, P-41) ; and
correction techniques  (12) .  A project
to update and develop practices for
determining and correcting infiltration
and its economic analysis (P-18, 166) is
nearing completion.  An in-house paper
on the analysis and evaluation of I/I has
been published  (R-14).  Another project
is evaluating the strength increases and
erosion resistance, and resulting infil-
tration prevention from sulfur impregnation
of concrete pipe  (P-30, 52).  Since pipe
costs are significant, an increase in
strength could lead to a decrease in pipe
materials and construction costs.

Flow Routing

    Another collection system control
method is in-sewer or in-line storage
and routing of storm flows to make
maximum use of existing interceptors
and sewer line capacity.  The general
approach comprises remote monitoring of
rainfall, flow levels, and sometimes
quality, at selected locations in the
network, together with a centrally
computerized console for positive
regulation.  This concept has proved to
be effective in Minneapolis-St. Paul  (19) ,
Detroit  (40, 118), and Seattle  (29, 98).
Seattle results are discussed later
(Section 7, pp 56-58) to indicate
potential control and cost benefits.

    An ongoing project mentioned earlier
with the City of San Francisco is develop-
ing an automatic operational model for
real-time control (P-25).  Future demon-
stration of the system is anticipated.
Regulators and Tide Gates

     Two early publications  in the area
of flow regulator technology were the
SOTA (23) and MOP  (24).

     Conventional regulators malfunction
and cause excessive overflows.   The new
improved devices such  as fluidic and
positive control regulators  have been
developed and demonstrated  (P-7, 9, 23,
24, 98, 173).  The swirl and helical
regulator devices are  significant enough
to single out separately.

     Swirl and Helical Device  Development
— The dual functioning swirl  device has
shown outstanding potential  for providing
both quality and quantity control (R-15,
93).

     A swirl flow regulator/solids-liquid
separator has been demonstrated in
Syracuse, NY  (P-2; R-16; 140a,  Chapter II,
pp 99-117).  Figure 18 is an isometric
view.  The device, of  simple annular
shape construction, requires no moving
parts.  It provides a  dual function,
regulating flow by a central circular
weir while simultaneously treating
combined wastewater by a "swirl" action
which imparts liquid-solids  separation.
The low-flow concentrate is  diverted via
a bottom orifice to the sanitary sewerage
system for subsequent  treatment at the
municipal works, and the relatively clear
supernatant overflows  the weir into a
central downshaft and  receives further
treatment or is discharged to  the stream.
The device is capable  of functioning
efficiently over a wide range  (80:1) of
combined sewer overflow rates,  and can
effectively separate suspended matter at
a small fraction of the detention time
required for conventional sedimentation
or flotation  (seconds  to minutes as opposed
to hours by conventional tanks).  Tests
indicate at least 50 percent removal of
suspended solids and BOD.  Tables 10 and
11 contain further treatability details
on the Syracuse prototype.   The captial
cost of the 6.8 mgd Syracuse prototype
was $55,000 or $8,100/mgd and  $l,000/ac
which makes the device highly  cost-
effective.

     The swirl concept (for  dual dry/wet
weather flow treatment) has  been piloted
                                           417

-------
as a degritter  (P-71) in Denver,  CO and as
a primary clarifier in Toronto, Canada
(P-71).  Test results are very encouraging
and the concept has been further  developed
for erosion control.

     A helical or spiral-type regulator/
separator has also been developed based on
principles similar to those of the  swirl
device.  Its solids separation action  is
created by only a bend in the sewer line.
It requires more land than the swirl
device but may be preferred where
available hydraulic head is limited.

     Swirl and Helical: Products  — Impor-
tant products for this category are design
manuals for the swirl (69, 93, 101)  and
helical (132) regulator/separators,  swirl
degritter (99) and swirl erosion  control
devices (151); and a Technology Transfer
Capsule Report  (162) which ties the
various swirl applications together.

Maintenance

     Improved sewerage system inspection
and maintenance is absolutely necessary
for a total system approach to municipal
water pollution control.  We cannot afford
the upgrading and proper operation
of sewage treatment plants while  a
significant amount of sewage leaks  into
streams at the upstream points in the
sewer network!  Premature overflows
and backwater intrusions during dry as
well as wet weather caused by malfunction-
ing regulators and tide gates, improper
diversion settings, and partially filled
interceptors can thus be alleviated.
Although the resulting abatement  obtained
is from a non-structural approach,  it  must
be viewed as an ancillary benefit of
required system maintenance.  Regulator
agencies should be anxious to strive for
policy to enforce collection system
maintenance.
                    LEGEND
              o InUt Ramp

              b Flow Deliverer

              c 5
-------
1971
1972
1973
                                   1974
                                      1975
1976
FUTURE
  DEM. UNDERWATER
    STORAGE (BAGS)
                   EVALUATE  IMPACTS OF
                     SOLIDS FROM STOR.
                      FAC. ON DWF PL.
  IN-SEWER STORAGE
 BY REMOTE CONTROL
              OFF-LINE STORAGE
               (TANKS/BASINS)
                              DEEP TUNNEL STOR.
                                  & ROUTING
                                               DESIGN MANUAL FOR
                                                STORAGE FACILITIES
                                                                DEM. NEW
                                                            CONFIGURATIONS
                                                            FOR STORAGE FAC.
                                                              F/S DEM.-SILO,
                                                           UNDERWATER BAGS,
                                                             FLOW ROUTING
                                                                   EVAL. SEEPAGE BASINS
                                                                   (CSO/SWR) (RECHARGE)
                                                                     DEM. STORAGE W/
                                                                   CONTROLLED RELEASE
                                                                      TO  REC. WATER
                                                                   EVAL. DUAL STORAGE
                                                                     OF DWF/WWF W/
                                                                  SECONDARY POLISHING
                                  Figure 19.   Storage

-------
TABLE 10 - SWIRL REGULATOR/CONCENTRATOR: SUSPENDED SOLIDS REMOVAL
Storm No.
02-1974
03-1973
07-1974
10-1974
14-1974
01-1975
02-1975
06-1975
12-1975
14-1975
15-1975
SWIRL CONCENTRATOR
Mass Loading
kg
% b
Inf. Eff. Rem.
374 179 52
69 34 51
93 61 34
256 134 48
99 57 42
103 24 77
463 167 64
112 62 45
250 168 33
83 48 42
117 21 82
Average SS
per storm, mg/1
% b
Inf. Eff. Rem.
535 345 36
182 141 23
110 90 18
230 164 29
159 123 23
374 167 55
342 202 41
342 259 24
291 232 20
121 81 33
115 55 52
CONVENTIONAL REGULATOR
Mass Loading
kg
%
Inf. Underflow Rem.a
374 101 27
69 33 48
93 20 22
256 49 19
99 26 26
103 66 64
463 170 34
112 31 27
250 48 19
83 14 17
117 72 61
 For the conventional regulator removal calculation, it is assumed that the SS
 concentration of the foul underflow equals the SS concentration of the inflow.

 Data reflecting negative SS removals at tail end of storms not included.
TABLE 11 - SWIRL REGULATOR/CONCENTRATOR: BOD REMOVAL
Storm No.
7-1974
1-1975
2-1975
Mass Loading, kg
%
Influent Effluent Rem.
277 48 82
97 30 69
175 86 51
Average BOD
per storm, mg/1
Influent Effluent
314 65
165 112
99 70
^0
Rem.
79
32
29
    The concept is to capture wet-weather
flow and bleed it back to the treatment
plant during low flow dry-weather
periods.  The result of controlling
overflow by detention is shown  on Figure
20.  Notice how an entire hypothetical
overflow event at point A is prevented by
storage with controlled dewatering.
                                                       RAINFALL
T
                                               HYDROGRAPH AT "A"
                                                WITHOUT CONTROL
             CONTROLLED
            HYDROGRAPH AT
                "A"
                                               Figure 20 - Results of Controlling Storm
                                                           Flow by Storage
                                           420

-------
     Storage  facilities  possess many of the
favorable  attributes  desired in combined
sewer overflow  control:  (1)  they are
basically  simple  in structural design
and operation;  (2)  they  respond without
difficulty to intermittent and
random storm  behavior;  (3)  they are
relatively unaffected by flow and quality
changes; and  (4)  they are capable of
providing  flow  equalization and, in the
case of sewers  and  tunnels,  transmission.
(Frequently they  can  be  operated in
concert with  regional dry-weather flow
treatment  plants  for  benefits during
both dry-  and wet-weather conditions
(107)). Finally, storage facilities
are relatively  fail-safe and adapt well
to stage construction.

     Storage  facilities  may be constructed
in-line or off-line;  they may be open or
closed; they  may  be constructed inland
and upstream, or  on the  shoreline; they
may have auxiliary  functions, such as
flood protection, sewer  relief, and
flow transmission.   (And they may be
used for hazardous  spill containment
during dry weather.)

     Disadvantages  of storage facilities
are their  large size  and dependency on
other treatment facilities for dewatering
and solids disposal.

     Storage  concepts investigated by the
program include the conventional concrete
holding tanks (18,  134)  and earthen basins
(30, 72);  and the minimum land require-
ment concepts of: tunnels (40), underground
(85) and underwater containers (15, 25,
26), underground  "silos  (96)," gravel
packed beds with  overhead land use (154) ,
natural (85)  and mined under and above
ground formations,  and the use of aban-
doned facilities  and  existing sewer lines
(19, 29, 98,  118).

     A 3.5 mg asphalt-lined storage
basin in Chippewa Falls,  WI  (72)  was
constructed on  reclaimed land and
eliminated 59 out of  62  overflows during
the evaluation  periods.

     Inherent in many of these storage
schemes is the  pumping/bleeding back of
the stored flow to  the DWF plant during
off-peak hours.  The  impacts of this
increased  load  on the DWF plant (both
from a hydraulic and  increased solids
point of view)  is an  important
consideration and  has  been investigated
in an ongoing project  (159,  161).

     The feasibility of  off-line  storage
and deep tunnel  storage  along waterways
for selective discharge  based on  least
receiving water  impacts  is presently
being investigated in  Rochester,  NY (P-15).
It is envisioned that  this concept along
with dual DWF/WWF  storage, will be
demonstrated in  post FY  76 plans  as
part of a tie-in to construction  grants.

     Future Program plans  include the
investigation of new storage configurations,
e.g., floating storage facilities,  coffer-
dams, storage under piers, etc.   Full-
scale demonstration of some of the more
promising configurations,  such as silos
and underwater bags, is  also desirable.

Treatment

     Due to adverse and  intense flow
conditions and unpredictable shock load-
ing effects, it  has been difficult to
adapt existing treatment methods  to storm-
generated overflows, especially the
microorganism dependent  biological
processes.  The  newer  physical/chemical
treatment techniques have  shown more
promise in overcoming  these  adversities.
To reduce capital  investments,  projects
have been directed towards high-rate
operations approaching maximum loading
boundaries.  Applications  include  pre-
treatment or roughing, main  or sole
treatment, and particularly  with micro-
strainers and filters, polishing  devices.

     The various treatment methods  which
have been developed and  demonstrated
by the Program for storm flow include
physical and physical-chemical, biological,
and disinfection (Figure 21).   These
processes, or combinations of these
processes, can be  adjuncts to the  existing
sanitary plant or  serve  as remote
satellite facilities at  the  outfall.

Physical/Chemical  Treatment

     Physical processes  with or without
chemicals, such  as: fine screens  (34,
37, 38, 78, 105);  swirl  primary separators
(162, P-29) and  swirl  degritters  (99,  162,
158, P-29); high-rate  filters (35,  P-39);
sedimentation (36,  81);  and  dissolved  air
flotation  (20, 21,  131); have been
developed and demonstrated by the  Program.
                                           421

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                                      PRE-FY76
                                                                           FY76
                                                                                                       FUTURE
PHYSICAL
W/ OR W/O
CHEM
DEV/PILOT


• FINE SCREENS
• SWIRL-GRIT/PRIM
• HI-RATE FILT
• DISS AIR FLOAT
• NH3:ION EX.BK PT
• P-C (AWT)






\
x \
\
\
DEM FULL-SCALE


• FINE SCREENS
• COAG SEDfCS/SW)
• SWIRL DEGRITTER
• HRF
• DAF

\


1 1
FINE SCREEN 1 DUAL USE 1
DEM.(CONT) ' SCREENING I

DEM FULL-SCALE
» SWIPL PRIMARY

                                                                                                             DEM.  FULL-SCALE
                                                                                                               AWT SYSTEM
LAND
DISPOSAL
(NON-STRUCT)
DEM. FULL-SCALE
MARSH LAND DISP (SW)


FEAS:LAND
DISP(CS/SW)


PILOT:
LAND DISP


DEM. FULL-SCALE
LAND DISP
BIOL
                                            DEM. FULL-SCALE
                                         • LAGOONS  • HRTF
                                         • CONT STAB  • RBCfPIL.)
   DUAL USE  |
I»CONT STAB  !
I              '
I»FLUIDIZED BEDl
I              I
DISINF
DEV/PILOT
• PATH/VIR DETECTION
•HI-RATE (MIX,CI02,03)
• ON-SITE GEN


DEM. FULL-SCALE
• CONV CI2(CS/SW)
• HI-RATE
•ON-SITE



• VIRUS DISINF
•CARCINOGENIC RES

                                              Figure  21.   Treatment

-------
Ammonia removal  (P-12 and advanced physical-
chemical-adsorption systems  (81)  have  also
been developed and tested at the  pilot
level.  Physical processes have shown
importance for stormwater treatment
because of their adaptability  to  automated
operation, rapid startup and shut-down
characteristics, high-rate operation,  and
very good resistance to shock  loads.

    A microstrainer is conventionally
designed for polishing secondary  sewage
plant  effluent at an optimum rate of
approximately 10 gpm/sg. ft.   Tests on a
pilot  microscreening unit of 23 micron
aperture in Philadelphis have  shown that
at high influx rates of 25-30  gpm/ sg. ft.,
suspended solids removals in combined
overflows as high as 90% can be achieved
(34, 78, 105) .  Comparison of  three
different fine screens is continuing at
Syracuse, NY (P-2) .

    A study in Cleveland  (35) showed  high
potential for treating combined sewer
overflows by in-pipe coagulation-filtration
using  anthrafilt and sand in a 7  foot  deep
bed.   With the high loadings of 16 to  32
gpm/sg. ft. surface area, removal of solids
was effectively accomplished throughout
the entire depth of filter column.  Test
work showed suspended solids removal up to
and exceeding 90 percent and BOD  removals
in the range of 60 to 80 percent.
Substantial reductions, in the order of
30 to  80 percent of phosphates, can also
be obtained.  A large-scale high-rate
filtration unit in New York City  is being
evaluated for the dual-treatment  of dry
and wet-weather flows  (P-39) .

    Results from a 5.0 mgd screening  and
dissolved-air flotation demonstration  pilot
plant  in Milwaukee  (20), indicate that
greater than 70 percent removals  of BOD
and suspended solids are possible.  By add-
ing chemical coagulants, 85 to 97 percent
phosphate reduction can be achieved as an
additional benefit.  Based on  these find-
ings two full-scale prototypes (20 and 40
mgd) have been demonstrated in Racine, WI
(P-23) .

Land Disposal

    As previously discussed,  the use  of
marshlands for disposal of stormwater  has
been demonstrated in Minnesota.   The
feasibility of land disposal of raw CSO
has also been investigated (161).   Because
of the cost of collection  and transportation
and large land requirements  this  concept
does not appear feasible.  Land disposal
of CSO sludges, liquid  or  dewatered,
appears feasible and promising for
ultimate sludge disposal;  however, further
investigation in this area is required.

Biological Treatment

     The following biological processes
have been demonstrated:  contact stabili-
zation (117), high-rate  trickling
filtration  (95), rotating  biological
contactors  (106), and lagoons (108,  30).
The processes have had positive evaluation,
but with the exception  of  long term
storage lagoons, must operate conjunctively
with DWF plants to supply  biomass, and
require some form of flow  equalization.

Disinfection

     Because disinfectant  and contact
demands are great for storm  flows, research
has centered on high-rate  applications by
mixing and more rapid oxidants, i.e.,
chlorine dioxide  (CIO2)  and  ozone  (03);  and
on-site generation  (149, 31,  34,  78,  94,
105, 119).  A continuing effort in Syracuse,
NY  (P-2) will involve viral  disinfection
and carcinogenic chlorine  residual compound
studies.

Treatment Process Performance

     Treatment process performance in terms
of design influx rate  (gpm/sq ft)  and 6005
and suspended solids  (SS)  removal
efficiency is provided  in  Table 12.   The
high-rate performance of the swirl, micro-
strainer, filter, and dissolved air
flotation is apparent when compared to
sedimentation.

Sludge Solids

     Due to the documented deleterious
effect of CSO on the quality of receiving
waters, WWF sludge handling  and disposal
has been given less emphasis previously  in
concession to the problems of treating the
combined overflow itself.  Sludge  handling
and disposal should be  considered an
integral part of CSO treatment because it
significantly affects the  efficiency  and
cost of the total waste  treatment system.
                                            423

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                  TABLE 12 - WET-WEATHER TREATMENT PLANT PERFORMANCE DATA
Device
Primary



Secondary

Control Alternatives
a,b
Swirl Concentrator
c
Microstrainer
d
High-Rate Filtration
d
Dissolved Air Flotation
e
Sedimentation
Representative Performance
Contact Stabilization
g
Physical-Chemical
Representative Performance
Design Loading
Rate
(gpm/ft2)
60
20
24
2.5
0.5




Removal Efficiency (%)
BOD5
25-60
40-60
60-80
50-60
25-40
40
75-88
85-95
85
SS
50
70
90
80
55
60
90
95
95
   Field, 197*6 (R-16)

  DSullivan, 1974  (101)

  CMaher, 1974 (105)

   Lager and Smith, 1974  (102); w/chem. add.; hi-rate  filter including pre-screens
  a
  "Performance data based on domestic wastewater  treatment

  fAgnew, et al., 1975  (117)

   Esimate based on performance of these units  for  domestic wastewater (102)
Flow characterization studies show that the
annual quantity of CSO solids is at least
equal to and in most cases greater than
solids from DWF.  For example, 29% of the
sewered population in the U.S. is served
by combined sewers.  This represents
a service area of 3xlO& acres.  Assuming
an average yearly rainfall of 36 in. and
50% of the runoff resulting in an overflow,
the yearly volume of CSO in the U.S. would
be 1.5x10^2 gal.  The corresponding average
yearly volume of sludge resulting from
treatment of all CSO nationwide is estimated
at 41xl09 gal or 2.8% of the volume tested.
The average solids content of this sludge
would be about 1%.  In comparison, an
average yearly volume of dry weather sludge
of 35xl09 gal may be expected from the same
service area.  Consequently, if nationwide
CSO treatment was instituted there would
be a problem equal to or greater than
the problem there now is with municipal
sludge.

     The chronology of the Program's WWF
sludge/solids technological advancement
is contained in Figure 22.  The need for
defining the problem was recognized and,
in FY 73, a contract was awarded  (P-21)
to characterize and preliminarily
quantify CSO sludge/solids and perform
treatability studies.  Sludge handling/
disposal techniques are also being
evaluated and a nationwide assessment of
the sludge problem has been conducted
(P-24) .  As part of this assessment, the
"impacts" of the following alternatives
                                           424

-------
      PRE-FY 76
         FY 76
FUTURE
    WWF SLUDGE/
SOLIDS  CHAR./QUANT.
DESK-TOP ANALYSIS OF
 HANDLING/DISPOSAL
     TECHNIQUES
 TREATABILITY STUDIES
       (BENCH)
   PILOT STUDIES  OF
 CONVENTIONAL TECH.
  (CENT.;ANAER.DIG.)
NATIONWIDE ASSESS. OF
WWF SLUDGE PROBLEM
                                EVAL.  IMPACTS OF WWF
                             SLUDGES/SOLIDS ON DWF PL.
                              EVAL. ALTERNATIVE SLUDGE/
                              SOLIDS HANDLING/DISPOSAL
                                     TECHNIQUES
                                                                   MOP FOR WWF SLUDGE/
                                                                SOLIDS HANDLING/DISPOSAL
                                  DEM. NEW SLUDGE/SOLIDS
                                   HANDLING TECH.(SWIRL)
                                   DEM. DISPOSAL OF WWF
                                     SLUDGES TO LAND
                                    (ALSO RAW  CSO/SW)
                               Figure 22.  Sludge/Solids

-------
are being considered: bleed-back  of  the
sludge to the municipal dry weather  treat-
ment plant, handling the sludges  with
parallel facilities at the dry weather
plant, handling the sludges at the site
of CSO treatment, and land disposal  of
either untreated or treated sludges.

Sludge: Products  (Table 13)

     Two reports are presently available
(159, 161).  The first covers the
characterization, treatability, and
quantification of CSO sludges and solids
and the second is a "rough cut" at
assessing the impact of handling  and
disposal.
   TABLE 13 - SLUDGE/SOLIDS: PRODUCTS
  Characterization and Quantification  of
  CSO Sludges and Solids  (Draft report
  available)  (159).

  WWF Sludge/Solids Impact Assessment
  (Preliminary report available)  (161).

  WWF Sludge/Solids Treatability  Studies
  (159).
     The characterization, quantification,
and treatability evaluation of sludges
from separate stormwater will be done in
the future.

Integrated Systems

     By far the most promising and common
approaches to urban stormwater management
involve the integrated use of control and
treatment with an areawide multidisciplinary
perspective.  When a single method is not
likely to produce the best possible answer
to a given pollution situation, various
treatment and control measures may be
combined for maximum flexibility and
efficiency.

     Integrated systems is divided into
(1) Storage/Treatment, (2) Dual Use
WWF/DWF Facilities, and  (3) Control/
Treatment/Reuse (Figure 23).

Storage/Treatment

     Where there is storage, there is
treatment by settling, pumpback to the
municipal works,  and sometimes disinfection-
and treatment, which receives detention,
provides storage.   In any case,  the break-
even economics of supplying storage must
be evaluated when treatment is considered
(35) .  The program has demonstrated all
of these storage-treatment concepts on a
full-scale basis  (15,  18,  25,  26,  29, 30,
40, 72, 102, 108,  114,  118,  134, 146, 147,
154, P-10, P-37).

Dual Use, WWF/DWF Facilities

     The concept  of dual  use is  — maximum
utilization of wet-weather facilities
during nonstorm periods and maximum utili-
zation of dry-weather facilities during
storm flows for total system effectiveness.
The program has demonstrated the dual use
of high-rate trickling filters (95) ,
contact stabilization (117),  and equali-
zation basins  (107,  114).   On  a pilot
scale the Program has  evaluated advanced
physical-chemical  treatment (81); and is
in the process of  demonstrating large-
scale, high-rate  filtration  (P-39).

     It should also be  mentioned that
combined sewers themselves are dual use
systems.

Control/Treatment/Reuse

     The sub-category,  "Control/Treatment/
Reuse" is a "catch-all" for  all integrated
systems.  As the prime  consideration, it
is reasonable to  apply  the various non-
structural and land management techniques
to reduce downstream loads and treatment
costs.

     Previous projects  have  evaluated the
reuse of stormwater runoff for aesthetic,
recreastional, and subpotable  and potable
water supply purposes  (62,  79).  In Mt.
Clemens, MI, a series  of  three "lakelets"
has been incorporated into a CSO treatment-
park development  (114).   Treatment and
disinfection is being provided so that
these lakes are aesthetically  pleasing
and allow for recreation  and reuse for
irrigation.  Other projects  have shown
the feasibility of reclaiming  stormwater
(3, 39).

     The previously mentioned Houston
project (P-16) is  focusing on how  a
"natural drainage system"  can be integrated
into a resue scheme for recreation and
aesthetics.
                                            426

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                       PRE-FY76
                                      FUTURE
 STORAGE/
 TREAT
DUAL USE,
WWF/DWF
FAC
    DEM. STORAGE W/
• PUMP-BACK
• SED. IN STORAGE
• STORAGE/TREAT LAGOON
• DISINF.
• BREAK-EVEN  ECON.
  W/TREAT
        DEM. TREAT
       HRTF (F/S)
       CONT STAB (F/S)
       HI-RATE FILT(F/S)
       P-C(AWT,PILOT)
                 DEM. EQUALIZATION
                    (ROHNERT PK.)
                 COMBINED SEWERS
   DEM.  TREAT
 • PHY-BIOL
 • DISS AIR FLOT
 • MICROSCREENS
                                    DEM. STORAGE
                                   • DWF/WWF
                                     W/EFFL POLISH
CONT/TREAT/
REUSE
   • LAND  MGMT/TREAT
   • TREAT-PK
   • STORAGE-TREAT
     LAKELETS
                   Figure 23.  Integrated Systems
DEM. STOR-TREAT-
    RECHARGE
                               427

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Integrated Systems: Products

     The specific outputs from the
integrated systems work have been pre-
dominantly in the form of demonstrations,
documented by final reports.  The previously
referenced SOTA Assessment Report  (102)
summarizes the work in this area and ties
it into wastewater management systems
planning, design, and program implemen-
tation.  Specific demonstration products
are classified into main and complementary
units for interrelating storm flow
devices and unit processes and interfacing
with dry-weather facilities.  In the future
it is important to evaluate storage used
for DWF and WWF along with secondary
effluent polishing.

 TECHNICAL ASSISTANCE/TECHNOLOGY TRANSFER

     The Technology Transfer area covers
the formal dissemination of Program find-
ings in the form of actual project reports,
films, journal papers, SOTA reports, and
manuals of practice and instruction.  To
date the Program has published approximately
160 reports, and it is the intent here to
concentrate on the "user" type of document.

Significant Documents Completed

     Reports generated by the program have
received widespread recognition both within
this country and abroad.  Many have been
referenced by EPA headquarters and used
for 201/208 studies.  Some of the more
significant documents are indicated in
Table 14.  The first set of reports, item
No. 1, set the pace for EPA's Program by
identifying stormwater and combined sewer
overflow as major sources of water
pollution and provided a characterization
data base (Refs. see item 1, Table 14).
As previously mentioned, the manuals of
practice on infiltration/inflow  (27, 28,
97) and regulators  (23, 24), Nos. 3 and 4,
flagged two prime and basic problems leading
to fruitful countermeasure research and a
national emphasis on I/I control.  Specific
research products coming out of the
regulator MOPs were the swirl  (69, 93, 99,
101) and helical  (132) devices — resul-
tant design manuals are listed as Nos.
5 and 6.  Number 8 cites two instrumen-
tation reports  (130, 133) for flow
analysis which have proven to be highly
useful to the engineering community,
including Construction Grants.  An
assessment of the significant impacts  of
highway deicing chemical use  (67, 86) and
practicable MOPs on  control through proper
salt storage and use (100, 104) are covered
by items 9 and 10.   Nos. 11 through 18
relate to Approach and Solution Methodology,
the goal of the program.   Item 19 refers to
two very important user' s  manuals containing
relatively simple urban runoff assessment
planning methods  (148, 153) which can be
applied to 201 and 208 studies; and item 20
cites the previously mentioned national
assessment of urban  runoff control and
costs (157).

Significant Documents Anticipated (Table 15)

     In the immediate future a construction
and OSM cost estimating manual (156)  for CSO
storage and treatment will be released,
along with three other assessments:  two on
WWF sludge handling, disposal, and impact
problems (159, 161) , and the other on
pathogens in stormwater (160).

     Ongoing work will also lead to an
updated SOTA and a planning document pro-
viding guidance and  examples for total
municipal studies  (P-5) and a refined
SWMM user's manual  (P-53).

 CAPITAL COSTS COMPARISON  FOR STORM AND
     COMBINED SEWER  CONTROL/TREATMENT

     Table 16 shows  a capital cost compari-
son for various SCS  control and treatment
methods.

     Sewer separation is very costly with a
national average of  $20,000/ac (2, 102).
In-system control storage  costs were found
to be as low as $0.02 and  $0.25/gal for
Detroit and Seattle, respectively (R-6d,
111).   These figures represented l/10th
the cost for large off-line facilities, and
l/25th the costs for separation in Detroit
and Seattle, respectively.  Off-line storage
varies from $0.03 to $4.75/gal depending on
whether earthen or concrete basins are
employed (102).

     Per acre costs  can only be given in
wide ranges since they  significantly vary
with climate, receiving water, terrain,
degree of urbanization, sewer network con-
figuration, etc.  Per capita and per acre
unit costs may be applicable for gross
estimating; but it  is best to fix unit
costs per gallon  for storage and per mgd
for treatment as  design factors for  the
user engineer confronted with  site-specific
conditions.
                                             428

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                       TABLE 14 - SIGNIFICANT DOCUMENTS  COMPLETED
  .  Assessment - Problems of CSO/SW  (2, 20, 34, 35, 41,  47,  51,  53,  54,  59,  60,  63, 65,
    67, 73, 81, 82, 83, 88, 102, 112, 123, 124, 127,  128,  143,  149)
 2.  CSO/SW Seminar Reports (6, 40, 96, 140a)
 3.  MOP - I/I Prevention and Correction (27, 28, 97)
 4.  MOP - Regulation and Management  (23, 24)
 5.  Design Manuals - Swirl: Regulator/Degritter/Erosion  Control (69,  93,  99, 101)
 6.  Design Manual - Helical Regulator/Separator  (132)
 7.  Assessments - Sources/Impacts of Urban Runoff Pollution  (157,  164,  127,  88,  128, 73)
 8.  Assessments - Sampling/Flowrate Measurement  (133,  130)
 9.  Assessment - Impact of Deicing  (67, 86)
10.  MOP's - Deicing Chemical Usage/Storage & Handling (100,  104)
11.  Assessment - SOTA Urban Stormwater Management Technology (102,  111,  137)
12.  User's Manuals - SWMM, Version I and II  (44, 116)
13.  Course Manual - SWMM Application  (125)
14.  SOTA - Urban Water Management Modeling  (136)
15.  MOP - Determination of Flowrates/Volumes  (140)
16.  Assessment/MOP - Stormwater Models  (141)
17.  MOP - Procedures for Stormwater Characterization/Treatment  Studies  (145)
18.  MOP's - Sediment & Erosion Control  (68, 70, 168,  169)
19.  User's Manuals - Simplified Urban Runoff Planning Models/Tools  (148,  153)
20.  Assessment - Nationwide Stormwater/Characterization/Impacts/Costs (157)
                      TABLE 15 - SIGNIFICANT DOCUMENTS ANTICIPATED
         - Estimating Manual - CSO Storage and  Treatment  Costs  (156)
         - User's Manual - SWMM Version III
         - Assessments - WWF Sludge Handling/Disposal  Problems/Impacts (159/161)
         - Assessment - Pathogens in Stormwater and  Combined  Sewer Overflow
           (160)
         - SOTA/Planning Guide - Update Storm and  Combined  Sewer  Overflow
           Management and Treatment/Total Approach Methodology
         - Design Manual - Swirl: Primary Treatment
         - MOP - I/I Analysis, Prevention and Control
         - Instruction Manual - Storm and Combined Sewer  Overflow Technology

         Post FY 76
         - MOP - Pollution Control from Construction Activities
         - MOP - Refined Solution Methodology
         - MOP - Land Management
         - Design Manual - Storage Facilities
         - Consolidated Design Text - Swirl and Helical
                                           429

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Table 16. Typical Capital Costs for SCS Control/Treatment (ENR 2000)
COMPONENT DEVICES
SEPARATION



STORAGE
• IN-LINE

• OFF-LINE
-EARTHEN
-CONCRETE TANKS
TREATMENT
• PHYSICAL W&W/O CHEMICALS
-FINE SCREENING/MICROSTRAINING
-SEDIMENTATION
-HI-RATE FILT
-DISS AIR FLOAT
-SWIRL

• BIOLOGICAL
-CON. STAB/TRICK. FILTER
-LAGOONS
• PHYSICAL-CHEMICAL SYSTEMS
• DISINFECTION
-CONVENTIONAL
-HI-RATE(STATIC MIXING)
INTEGRATED SYSTEMS
• STORAGE/TRMT/REUSE
-TREATMT-PARK CONCEPT
LAND MANAGEMENT
• STRUCTURAL
-DIVERSION BERMS
• NON-STRUCTURAL
-STREET CLEANING
J/GAL





0.02 0.25
(DETROIT) (SEATTLE)

0.03-0.26
1.00-4.75























S/MGD












5,000/12,000
10,000-50,000
70,000
40,000
8,000 (SYRACUSE)
2,000 (LANCASTER)

80,000
17,000
150,000-2*106

1,500
900

t*106(KING«AN LAKE)
17,000(«T. CLEMENS)





S/ACRE
10,000 (SEATTLE)
6,500 (DES MOINES)
32,000 (CLEVELAND)
20,000-NATIONAL AVE.

400 (SEATTLE)
250 (MINNEAPOLIS)


7,000 (JAMAICA.NYC)


2,000/13,000
3,500-6,500
10,000
6,500 (MILWAUKEE)
SOO(SYRACUSE)
SOO(LANCASTER)

1,700
5,000





10,000(KINGMAN LAKE)
5,000(MT. CLEMENS)


160

0.7
430

-------
    These data are based on a limited
number of specific projects thus they
represent only a range of placement.  In
extrapolating these costs into master
plan systems for cities, the totals
frequently approach $500 to $1,000 per
capita.

    Physical treatment costs range
between $2,000 and $35,000/mgd; whereas
physical with chemical treatment
varies between $35,000 and $80,000/mgd.
Biological treatment ranges between
$17,000 and $80,000/mgd depending on
whether land is available for lagooning
or if contact stabilization or trickling
filtration  (102) is resorted to.  As can
be seen from the table, costs for the
swirl at  $2,000/mgd and $500/acre  (P-4)
are considerably lower than other forms
of treatment installation.

    Preliminary figures for incorporating
land management techniques show a definite
cost-effectiveness benefit.

    It must be mentioned that the
various alternatives offer different
degrees of removal which will have a
significant bearing on the selection
process.

SEATTLE:  IN-LINE STORAGE IS COST-EFFECTIVE

    A case study illustrating cost-
effectiveness by Seattle's flow routing
approach  is worthwhile discussing  (98,
140a).

Costs

    The  Seattle in-line storage system
covering  13,250 acres costs $5.3 million
or $400 per acre as opposed to tens of
thousands of dollars per acre for other
alternatives.  A specific Seattle study
revealed  $10,000 per acre for separation.
The low cost is attributed to a quasi-
structural system which takes advantage
of the existing combined sewer network;
and control gates installed at
strategic points only.  The system is
highly signal and  computer oriented with
minimal hardware requirements.  In fact,
one-half the costs were for computers
and related software.  Of course, in-line
storage is site specific since implemen-
tation of the concept requires a relatively
large and flat existing combined system.
Pollutant Reduction

     Overflow and pollutant reduction from
12 major overflow points  averaged 55%
and 68%, respectively.  Also,  90% of
the overflow volume was reduced by
experimental automatic control.

Effectiveness

     Effectiveness of the system is
proven by a one to two mg/1 D.O. increase
and a 50% coliform reduction in the
receiving water.

       DBS MOINES:  CONTROL COSTS
          VERSUS-D.O. VIOLATIONS

     Based on a study for the City of
Des Moines  (157) using a  simplified
receiving water model, four control
alternatives were compared considering
cost and true effectiveness in terms of
frequency of D.O. standard violations.

     As Table 17 depicts, 25% BOD removal
of WWF coupled with secondary treatment
of DWF results in slightly higher D.O.
levels in the receiving water than tertiary
treatment and no control  of urban runoff.
The annual cost of 25% BOD removal for WWF
is 10% of the cost for tertiary treatment.
However, existing DWF treatment facilities
exhibit a comparable effect to these two
options at no additional  cost.   However,
significant increase in the minimum D.O.
levels of the Des Moines  River is obtained
by 75% BOD removal of WWF with the annual
cost of this level of control being lower
than the cost of tertiary treatment.  The
application to Des Moines demonstrated
clearly the overwhelming  effect of urban
runoff pollution on critical D.O. concen-
trations.  The cost-effectivenss of various
treatment alternatives can be determined
realistically only by a continuous
analysis of the frequency of water quality
violations.

     In the selection of  the "best"
control strategy, other factors that may
become important are:  (1) recovery of
receiving waters from shock loads caused
by runoff,  (2) local and  regional water
quality goals, and  (3) public willingness
to pay the costs associated with each level
of control.
                                           431

-------
TABLE 17 - DBS MOINES:  CONTROL COSTS VERSUS VIOLATIONS OF  DO STANDARD (4  PPM)
Options
1. DWF Tertiary Treatment
2. WWF 25% BOD Removal
3. WWF 75% BOD Removal
4. DWF Secondary Trt Only
Total Annual Cost
(S/yr)
6.3M
0.6M
4.0M
0
% of Precipitation Events
Violating Standard
40
30
3
42
                                       432

-------
                    REFERENCES AND BIBLIOGRAPHY

        Bibliography of Urban Runoff Control Program Reports
   Ongoing Urban Runoff Pollution Control Projects  ("P" Numbers)
Other Urban Runoff Pollution Control Program References ("R" Numbers)
                                433

-------
   BIBLIOGRAPHY OF URBAN RUNOFF POLLUTION CONTROL PROGRAM REPORTS
Ref.
No.
    Report Number
Title/Author
Source
1.  11020—09/67
2.  11020—12/67
3.  11020—05/68
4.  11020—06/69
5.  11020—10/69
6.  11020—03/70
    11020—02/71
8.  11020DES06/69
9.  11020DGZ10/69
                          Demonstrate the Feasibility of the    NTIS ONLY
                          Use of Ultrasonic Filtration in       PB 201  745
                          Treating the Overflows from Combined
                          and/or Storm Sewers:  by Accoustica
                          Assoc., Inc., Los Angeles, CA

                          Problems of Combined  Sewer Facilities NTIS ONLY
                          and Overflows-!967:  by AmericanPB 214  469
                          Public Works Assoc.,  Chicago, IL

                          Feasibility of a Stabilization-       NTIS ONLY
                          Retention Basin in Lake Erie at       PB 195  083
                          Cleveland, OH: by Havens and Emerson,
                          Cleveland, OH

                          Reduction in Infiltration by Zone     NTIS ONLY
                          Pumping: by Hoffman  and Fiske,        PB 187  868
                          Lewiston, ID

                          Crazed Resin Filtration of Combined   NTIS ONLY
                          Sewer Overflows: by  Hercules, Inc.,   PB 187  867
                          Wilmington, DE

                         *Combined Sewer Overflow Seminar       NTIS
                          Papers: by Storm and  Combined Sewer   PB 199  361
                          Pollution Control Branch, Division of
                          Applied Science and  Technology, FWQA,
                          Washington, DC

                         *Deep Tunnels in Hard  Rock: by College NTIS
                          of Applied Science and Engineering    PB 210  854
                          and University Extension, University
                          of Wisconsin, Milwaukee, WI

                          Selected Urban Water  Runoff Abstracts:NTIS ONLY
                          by The Franklin Institute, Phila-PB 185  314
                          del phi a, PA

                          Design of a Combined  Sewer Fluidic    NTIS ONLY
                          Regulator: by Bowles  EngineeringPB 188  914
                          Corp., Silver Spring, MD
*Copies may be obtained from EPA Storm & Combined Sewer Section,
 Edison, NJ 08817
Note: Number in left margin corresponds to reference numbers cited in report
      text.
                                    434

-------
Ref.
No.    Report Number
  Title/Author
Source
 10.  TI020DH006/72



 11.  11020DIG08/69


 12.  11020DIH06/69



 13.  11020DN008/67



 14.  11020DN003/72




 15.  11020DWF12/69




 16.  11020EK010/69



 17.  11020EXV07/69



 18.  11020FAL03/71



 19.  11020FAQ03/71



 20.  11020FDC01/72




 21.  11020FKI01/70



 22.  11022DEI05/72
*Copies may be obtained
 Edison, NJ 08817
 *Ground Water Infiltration and
NTIS
  Internal Seal ings of Sanitary Sewers, PB 212 267
  Montgomery County, OH: by G.E. Cronk

  Polymers for Sewer Flow Control: by   NTIS ONLY
  The Western Co., Richardson, TX       PB 185 951

  Improved Sealants for Infiltration    NTIS ONLY
  Control: by The Western Company.PB 185 950
  Richardson, TX

  Feasibility of a Periodic Flushing    NTIS ONLY
  System for Combined Sewer Cleansing:  PB 195 223
  by FMC Corp., Santa Clara, CA

 *A Flushing System for Combined Sewer  NTIS
  Cleansing: by Central EngineeringPB 210 858
  Laboratories, FMC Corp., Santa
  Clara, CA
  Control of Pollution by Underwater    NTIS ONLY
  Storage: by Underwater Storage, Inc., PB 191 217
  Silver, Schwartz, Ltd., Joint Ven-
  ture, Washington, DC

  Combined Sewer Separation Using       NTIS ONLY
  Pressure Sewers: by American Society  PB 188 511
  of Civil Engineers, Cambridge, MA

  Strainer/Filter Treatment of Combined NTIS ONLY
  Sewer Overflows: by Fram Corporation, PB 185 949
  East Providence, RI

 *Evaluation of Storm Standby Tanks,    NTIS
  Columbus, OH: by Dodson, Kinney &     PB 202 236
  Lindblom, Columbus, OH

 *D1spatching Systems for Control of    NTIS
  Combined Sewer Losses: by Metro^PB 203 678
  Sewer Board, St. Paul, MN

  Screening/Flotation Treatment of      GPO ONLY
  Combined Sewer Overflows: by The
  Ecology Division, Rex Chainbelt, Inc.,
  Milwaukee, WI

  Dissolved-Air Flotation Treatment of  NTIS ONLY
  Combined Sewer Overflows: by Rhodes   PB 189 775
  Corp., Oklahoma City, OK
 *Sewer Bedding and Infiltration Gulf   NTIS
  Coast Area: by J.K.Mayer. F.W.Mac     PB 211
  Donald, and S.E.Steimle; Tulane Univ.,
  New Orleans, LA

from EPA Storm & Combined Sewer Section,
                                    435
                                                                       282

-------
Ref.
No.   Report Number
  Title/Author
Source
 23.   11022DMU07/70
 24.   11022DMU08/70
 25.   11022DPP10/70
 26.   11022ECV09/71
 27.   11022EFF12/70
 28.   11022EFF01/71
 *Combined Sewer Regulator Overflow
  Facilities:  by American Public Works
  Assoc., Chicago, IL
GPO ONLY
 29.   11022ELK12/71



 30.   11023—08/70



 31.   11023DAA03/72



 32.   11023DPI08/69



 33.   11023DZF06/70



 34.   11023EV006/70



 35.   11023EYI04/72
*Copies may be obtained
 Edison, NJ 08817
 *Combined Sewer Regulation and Manage- NTIS
  ment A Manual  of Practice: by AmericanPB 195 676
  Public Works Assoc., Chicago, IL

 *Combined Sewer Temporary Underwater   NTIS
  Storage Facility:  by Mel par, Falls    PB 197 669
  Churcfi, VA

  Underwater Storage of Combined Sewer  NTIS ONLY
  Overflows: by Karl R. Rohrer Assoc.,  PB 208 346
  Inc., Akron, OH

  Control of Infiltration and Inflow    NTIS ONLY
  into Sewer Systems: by American       PB 200 827
  Public Works Assoc., Chicago, IL

 *Prevention and Correction of Exces-   NTIS
  sive Infiltration  and Inflow intoPB 203 208
  Sewer Systems-A Manual of Practice:
  by American Public Works Assoc.,
  Chicago, IL

  Maximizing Storage in Combined Sewer  NTIS ONLY
  Systems: by Municipality of Metro-PB 209 861
  poll tan Seattle, WA

 *Retention Basin Control  of Combined   NTIS
  Sewer Overflows: by SpringfieldPB 200 828
  Sanitary District, Springfield, IL

 *Hypochlorite Generator for Treatment  NTIS
  of Combined Sewer  Overflows: "by       PB 211 243
  Ionics, Inc.,  Watertown, MA

  Rapid-Flow Filter  for Sewer Over-     NTIS ONLY
  flows: by Rand Development Corp.,     PB 194 032
  Cleveland, OH

 *Ultrasonic Filtration of Combined     NTIS
  Sewer Overflows: by American Process  PB 212 421
  Equipment Corp., Hawthorne, CA

 *Microstraining and Disinfection of    NTIS
  Combined Sewer Overflows: by Cochrane PB 195 674
  Div., Crane Co., King of Prussia, PA

 *High Rate Filtration of Combined      NTIS
  Sewer Overflows: by Ross Nebolsine,   PB 211 144
  P.J.Harvey, and Chi-Yuan Fan, Hydro-
  technic Corp., New York  NY

from EPA Storm & Combined Sewer Section,
                                    436

-------
 Ref.
 No.   Report Number
 Title/Author
Source
 36.  11023FDB09/70
 37.  11023FDD03/70
 38.  11023FDD07/71
 39.  11023FIX08/70
 40.  11024—-06/70
 41.  11024DMS05/70



 42.  11024DOC07/71



 43.  11024DOC08/71



 44.  11024DOC09/71



 45.  11024DOC10/71



 46.  11024DOK02/70
*Chemical Treatment of Combined Sewer  NTIS
 Overflows: by Dow Chemical Company.   PB 199 070
 Midland, MI

 Rotary Vibratory Fine Screening of    NTIS ONLY
 Combined Sewer Overflows: by Cornell  PB 195 168
 Howl and, Hayes and Merryfield, Cor-
 vallis, OR

*Dempnstration of Rotary Screening for NTIS
 Combined Sewer Overflows: by City of  PB 206 814
 Portland, Dept. of Public Works,
 Portland, OR

Conceptual Engineering Report-        NTIS
 Kingman Lake Project:"by RoyT.       PB 197 598
 Weston, West Chester, PA

*Combined Sewer Overflow Abatement     NTIS
 Technology: by Storm and Combined     PB 193 939
 Sewer Pollution Control-Branch,
 Division of Applied Science and
 Technology, FWQA, Washington, DC

*Engineering Investigation of Sewer    NTIS
 Overflow Problems: by Hayes. Seay.    PB 195 201
 Mattern and Mattern, Roanoke, VA

*Storm Water Management Model,         NTIS
 Vol. 1. Final Report: by Metcalf &    PB 203 289
 Eddy Engineers, Palo Alto, CA

 Storm Water Management Model. Vol.    NTIS ONLY
 II. Verification and Testing: by ~    PB 203 290
 Metcalf & Eddy Engineers, Palo AHo.CA

 Storm Water Management Model. Vol.    NTIS ONLY
 III, User's Manual: by Metcalf &PB 203 291
 Eddy Engineers, Palo Alto, CA

 Storm Water Management Model, Vol.  IV NTIS ONLY
 Program Listing: by Metcalf & EddyPB 203 292
 Engineers, Palo Al to., CA
*Proposed Combined Sewer Control by
 Electrode Potential: by Merrimack
 College, Andover, MA
NTIS
PB 195 169
 47.  11024DQU10/70     *Urban  Runoff  Characteristics: by
*Copies  may  be  obtained
 Edison, NJ  08817
 	NTIS
 University of Cincinnati, Cincinnati, PB 202 865
 OH

from EPA Storm & Combined Sewer Section,
                                    437

-------
Ref.
No.   Report Number
  Title/Author
Source
 48.   11024EJC07/70




 49.   11024EJC10/70




 50.   11024EJC01/71




 51.   11024ELB01/71




 52.   11024EQE06/71



 53.   11024EQG03/71




 54.   11024EXF08/70



 55.   11024FJE04/71




 56.   11024FJE07/71




 57.   D  E  L  E  T  E

 58.   11024FKJ10/70




 59.   11024FKM12/71
*Copies may be obtained
 Edison, NJ 08817
  Selected Urban Storm Water Runoff     NTIS ONLY
  Abstracts. July 1968-June 1970: by    PB 198 228
  The Franklin Institute Research Lab.,
  Philadelphia, PA

 *Selected Urban Storm Water Runoff     NTIS
  Abstracts, first Quarterly Issue:     PB 198 229
  by The Franklin Institute Research
  Lab.,  Philadelphia,  PA

 *Selected Urban Storm Water Runoff     NTIS
  Abstracts, Second Quarterly Issue:    PB 198 312
  by The Franklin Institute Research
  Lab.,  Philadelphia,  PA

 *Storm  and Combined Sewer Pollution    NTIS
  Sources and Abatement. At!anta,~GA:    PB 201  725
  by Black, Crow and tiasness,  inc.,
  Atlanta, GA

 impregnation of Concrete Pipe: by     GPO
  Southwest Research Institute,
  San Antonio, TX

  Storm  Water Problems and Control  in    NTIS ONLY
  Sanitary Sewers. Oakland & Berkeley",   PB 208 815
  CA: by Metcalf & Eddy Engineers,
  PFlo Alto, CA

 *Combined Sewer Overflow Abatement     NTIS
  Alternatives, Washington, DC: by~Roy   PB 203 680
  F- Weston, Inc., West Chester, PA

 *Selected Urban Storm Water Runoff     GPO
  Abstracts, Third Quarterly Issue:'
  by Franklin Institute Research Lab.,
  Philadelphia, PA

 *Selected Urban Stormwater Runoff      GPO
  Abstracts July 1970 -June 1971: by
  The Franklin Institute Research Lab.,
  Philadelphia, PA

D                        DELETED

 *In-Sewer Fixed Screening of Combined   NTIS
  Sewer  Overflows: by Envirogenics Co., PB 213 118
  Div. of Aerojet General Corp.,
  El Monte, CA

  Urban  Storm Runoff and Combined       NTIS ONLY
  Sewer Overflow Pollution. SacTeTmento. PB 208 989
  CA: by Envirogenics Co., Div. of
  Aerojet General Corp., El Monte, CA

from EPA Storm & Combined Sewer Section,
                                   438

-------
Ref.
No.    Report  Number
                         Title/Author
Source
 60.  11024FKN11/69
 61.   11024FLY06/71
 62.   11030DNK08/68
 63.   11030DNS01/69
 64.  11034DUY03/72
 65.  11034FKL07/70
 66.  11034FLU06/71
 67.  11040GKK06/71
 68.  15030DTL05/70
                        *Stream Pollution and Abatement from
                         Combined Sewer Overflows, Bucyrus.~
                         OH.: by Burgess and N1 pie, Ltd.,
                         Columbus, OH

                        *Heat Shrinkable Tubing as Sewer
                         Pipe Joints: by The Western Co. of
                         North America, Richardson, TX

                         The Beneficial Use of Stormwater: by
                         Hittman Associates, Inc., Baltimore,
                         MD

                         Mater Pollution Aspects of Urban
                         Runoff: by American Public Works
                         Assoc., Chicago, IL

                        •"Investigation of Porous Pavements
                         for Urban Runoff Control: by
                         E. Thelen, W.C.Grover, A.J.Hoi berg,
                         and T.I.Haigh, The Franklin Institute
                         Research Lab., Philadelphia, PA

                         Stormwater Pollution from Urban Land
                         Activity:by AVCO Economic Systems
                             ivity:
                             JTTwa
NTIS
PB 195 162
NTIS
PB 208 816
NTIS ONLY
PB 195 160
NTIS ONLY
PB 215 532
NTIS
PB 227 516
NTIS ONLY
PB 195 281
                         Corp., Washington, DC
                        *Hydraulics of Long Vertical Conduits  GPO
                         and Associated Cavitation: by Uni-
                         versity of Minnesota, Minneapolis, MN

                        *Environmenta1 Impact of Highway       NTIS
                         Deicing: by Edison Water Quality      PB 203 493
                         Laboratory, EPA, Edison, NJ

                         Urban Soil Erosion and Sediment       NTIS ONLY
                         Control: by National Association of   PB 196 111
                         Counties Research Foundation,
                         Washington, DC
 69.  EPA-R2-72-008
 70.  EPA-R2-72-015
                        *The Swirl Concentrator as a Combined
                         Sewer Overflow  Regulator Facility:
                         by American Public Works Assoc.,
                         Chicago,  IL

                         Guidelines for  Erosion and Sediment
                         Control Planning and  Implementation:
                         by the  Dept. of Water Resources,
                         State of  MD, and Hittman Assoc.,  Inc.,
                         Columbia, MD

*Copies may be obtained from the  EPA Storm and  Combined  Sewer Section,
 Edison,  NJ 08817
GPO $2.25
EP 1.23/2:72-008
NTIS
PB 214 687

NTIS ONLY
PB 213 119
                                       439

-------
Ref.
No.   Report Number	Title/Author	Source

 71   EPA-R2-72-068      *Storm Sewer Design-An Evaluation  of    GPO
                          the RRL Method: by J.B.Stall and       EP 1.23/2:72-068
                          M.L.Tierstriep, Illinois State Water   NTIS
                          Survey, University of Illinois         PB 214  134
                          Urbana, IL

 72   EPA-R2-72-070      *Storage and Treatment of Combined     GPO
                          Sewer Overflows; by the City of        EP 1.23/3:72-070
                          Chippewa Falls, WI                     NTIS
                                                                 PB 214  106

 73.  EPA-R2-72-081      *Uater Pollution Aspects of Street     GPO
                          Surface Contaminants: by J.D.Sartor    EP 1.23/2:72-081
                          and G.B.Boyd, URS Research Co.,        NTIS
                          San Mateo, CA                          PB 214  408

 74.  EPA-R?-72-082      *Feasibility Study of Electromagnetic   GPO
                          Subsurface Profiling: by R.M. Morey    EP 1.23/2:72-082
                          and W.S. Harrington, Jr., Geophysical  NTIS
                          Survey Systems, Inc., North BillericaPB 213 892
                          MD

 75.  EPA-R2-72-091      *A Pressure Sewer System Demonstration•GPO
                          by I.G.Carcich, et al, New York State  EP 1.23/2:72-091
                          Department of Environmental Conserva-  NTIS
                          tion, Albany, NY                       PB 214  409

 76.  EPA-R2-72-125      *A Search: New Technology for Pave-     GPO
                          ment Snow and Ice Control: byEP 1.23/2:72-125
                          D.M. Murray and M.R. Eigerman,         NTIS
                          ABT Associates, Inc., Cambridge,  MD    PB 221  250

 77.  EPA-R2-72-127      *Selected Urban Stormwater Runoff       GPO
                          Abstracts. July 1971-June 1972:        EP 1.23/2:72-127
                          by D.A. Sandoski, The Franklin In-     NTIS
                          stitute Research Lab., Philadelphia,   PB 214  411
                          PA

 78.  EPA-R2-73-124       Microstraining and Disinfection of     GPO
                          Combined Sewer Overflows-Phase II:     EP 1.23/2:73-124
                          by G.E. Glover, G.R. Herbert, Crane    NTIS
                          Company, King of Prussia, PA           PB 219  879

 79.  EPA-R2-73-139      *The Beneficial Use of Stormwater:      GPO
                          by C.W. Mallory, Hittman Associates,   EP 1.23/2:73-139
                          Columbia, MD                           NTIS
                                                                 PB 217  506

 80.  EPA-R2-73-145      *A Thermal  Wave Flowmeter for          GPO
                          Measuring Combined Sewer Flows:       EP 1.23/2:73-145
                          by P.  Esnleman and R. Blase, Hydro-   NTIS
                          space Challenger, Inc.,  Rockville, MD PB 227 370

*Copies  may be obtained from EPA Storm and Combined Sewer Section,
 Edison, NJ 08817
                                       440

-------
Ref.
No.
    Report Number     Title/Author
Source
 81.  EPA-R2-73-H9     Physical-Chemical Treatment of Com-
                       bined and Municipal Sewage: by A.J.
                       Shuckrow, et al., Pacific NW Lab.,
                       Battelle Memorial Institute,
                       Rich!and, WA

 82.  EPA-R2-73-152    *Cpmbined Sewer Overflow Study for
                       the Hudson River Conference: by A.I.
                       Mytelka, et al., Interstate Sanita-
                       tion Commission, New York, NY
                       (jointly sponsored by Office of En-
                       forcement & General Council and
                       Office of Research & Monitoring, EPA)

 83.  EPA-R2-73-170    *Cgmbined Sewer Overflow Abatement
                       Plan, Des Moines, IA: by P.L.Davis,
                       et al., Hennington, Durham, and
                       Richardson, Inc., Omaha, NE

                      *Flow Augmenting Effects of Additives
                       on Open Channel Flows: by C. Derick
                       and K. Logie, Columbia Research Inc.,
                       Gaithersburg, MD

                      *Temporary Detention of Storm and
                       Combined Sewage in Natural Und'eT-
84.   EPA-R2-73-238
85.   EPA-R2-73-242
 86.  EPA-R2-73-257
                       ground  Formations:
                       Paul, St.  Paul, MN
                                         by City of St.
 87.  EPA-R2-73-261
  5.   EPA-R2-73-283
 88a  EPA-600/2-73-002
                      Water Pollution and Associated
                      Effects from Street Salting: by
                      R.Field, H.E.Masters, A.N.Tafuri,
                      Edison Water Quality Research Lab.,
                      EPA, Edison, NJ and E.J.Struzeski,
                      EPA, Denver, CO

                     *An Assessment of Automatic Sewer
                      Flow Samplers: by P.E.Shelley and
                      G.W.Kirkpatrick, Hydrospace Challenger
                      Inc., Rockville, MD

                     *Toxic Materials Analysis of Street
                      Surface Contaminants:  by R.E.Pitt and
                      G.Amy, URS Research Co., San Mateo,
                      CA

                      A Portable Device for Measuring Waste-
                      water Flow in Sewers: by Michael A.
                      Nawrocki, Hittman Associates, Inc.,
                      Columbia, MD
                                                              GPO
                                                              EP 1.23/2:73-149
                                                              NTIS
                                                              PB 219 668
                                                              GPO
                                                              EP 1.23/2:73-152
                                                              NTIS
                                                              PB 227 341
                                                              GPO
                                                              EP 1.23/2:R2-73-170
GPO
EP 1.23/2:73-238
NTIS
PB 222 911

GPO
EP 1.23/2:73-242
In-House
Report
NTIS
PB 222 795
GPO
EP 1.23/2:R2-73-261
NTIS
PB 223 355

GPO
EP 1.23/2:R2-73-283
NTIS
PB 224 677

GPO
EP 1.23/2:600/2-73-002
NTIS
PB 235 634
*Copies may be obtained from EPA Storm and Combined Sewer Section,
 Edison, NJ 08817
                                         441

-------
 Ref.
 No.   Report Number     Title/Author	Source	

  89   EPA-660/2-73-035  Joint  Construction  Sediment Control    GPO
                        Project:  by B.C.Becker,  et al..EP 1.23/2:660/2-73-035
                        Water  Resources  Administration,  State NTIS
                        of Maryland                            PB 235 634

  90   EPA-660/2-74-071  Programmed Demonstration for Erosion  GPO
                        and_Sediment  Control  Specialist"EP 1.23/2:660/2-74-071
                        by T.R.Mills,  et al.,  Water Resources
                        Administration,  State  of Maryland

  91.  EPA-660/2-74-072  Demonstration  of the  Separation  and    GPO
                        Disposal  of Concentrated Sediments:    EP 1.23/2:660/2-74-072
                        by M.A.Nawrocki, Hittman Associates,
                        Columbia, MD

  92.  EPA-660/2-74-073  An Executive  Summary  of  Three EPA      GPO
                        Demonstration  Programs in Erosion      EP 1.23/2:660/2-74-073
                        and  Sediment  Control:  by B.C.Becker
                        et al., Hittman  Associates, Columbia,
                        MD

  93.  EPA-670/2-73-059 *The  Dual-Functioning Swirl  Combined    GPO
                        Sewer  Overflow Regulator/Concentrator:EP 1.23/2:670/2-73-059
                        by R.Field, USEPA,  Edison,  NJNTIS
                                                               PB 227 182/3

  94.  EPA-670/2-73-067 *Hypochlorination  of Polluted  Storm-    GPO
                        water  Pumpage  at  New Orleans:  by U.R.  EP 1.23/2:670/2-73-067
                        Pontius,  E.H.Pavis, Byrne Engi-        NTIS
                        neering Corp., New Orleans,  LA        PB 228 581

  95.  EPA-670/2-73-071 Utilization of Trickling Filters for  GPO
                        Dual-Treatment of Dry  and Wet-HeatRir EP 1.23/2:670/2-73-071
                        Flows: by P.Homack. et al.,  E.T.NTIS
                        'RTTTam Assoc., Inc., Mi 11 burn, NJ      PB 231  251

  96.  EPA-670/2-73-077 Combined  Sewer Overflow  Seminar        GPO
                        Papers: by Storm  and Combined Sewer    EP 1.23/2:670/2-73-077
                        Technology Branch, USEPA,  Edison, NJ  NTIS
                                                               PB 231  836

  97.  EPA-670/9-74-004 *Excerpts from "Control of Infiltra-   NTIS Pending
                        tion and Inflow into Sewer Systems,"
                        and  "Prevention and Correction of Ex-
                        cessive Infiltration and  Inflow into
                        Sewer Systems Manual of  Practice,
                        January"1971."Complete  reports can
                        be purchased from NTIS,   See  PB numbers
                        listed on third page of  this  Bibliography.

 98.   EPA-670/2-74-022 Computer Management of a  Combined     GPO
                        Sewer System:  by C.P.Leiser. Muni-    EP  1.23/2:670/2-74-022
                        cipality of Metropolitan  Seattle,     NTIS
                        Seattle,  WA                           PB 235 717

•"Copies  may be  obtained  from  EPA Storm & Combined Sewer Section,
 Edison, NJ 08817

                                            442

-------
 Ref.
 No.   Report Number     Title/Author	Source	

 99.  EPA-670/2-74-026 *The Swirl  Concentrator as a Grit      NTIS
                        Separator Device: by R.H.Sullivan,    PB 233 964
                        et al., American Public Works Assoc.,
                        Chicago, IL

 TOO.  EPA-670/2-74-033 *Manual  for Deicing Chemical Storage   NTIS
                        and Handling: by D.L.Richardson, et   PB 236 152
                        al., Arthur D. Little, Inc.,
                        Cambridge, MD

 101.  EPA-670/2-74-039 *Relationship between Diameter and     NTIS
                        Height for Design of a Swirl Concen-  PB 234 646
                        trator as a Combined Sewer Overflow
                        Regulator: by R.H.Sullivan, et al.,
                        American Public Works Assoc.,
                        Chicago, IL

 102.  EPA-670/2-74-040 *Urban Stormwater Management and       NTIS
                        Technology An Assessment:PB 240 687
                        by J.A.Lager and W.G.Smith, Metcalf
                        & Eddy, Inc., Palo'Alto, CA

 103.  EPA-660/2-74-043  Prediction of Subsoil Erodibility     GPO
                        Using Chemical. Mineralogical and'     EP 1.23/2:660/2-74-043
                        Physical Parameters: by  C.B.Roth.     NTIS
                        D.W.Nelson, M.J.M.Romkens,            PB 231 846
                        Cincinnati, OH

 104.  EPA-670/2-74-045 *Manual for Deicinq Chemicals: Appli-  NTIS
                        cati on Practi ces: D.L.R1chardson,PB 239 694
                        Arthur D. Little, Inc.,  Cambridge, MD

 105.  EPA-670/2-74-049 *Microstraining and Disinfection of    GPO
                        Combined Sewer Overflows-Phase IlTT  EP 1.23/2:670/2-74-049
                        by M.B.Maher, Crane Co., King ofNTIS
                        Prussia, PA                           PB 235 771

 106.  EPA-670/2-74-050  Combined Sewer Overflow  Treatment     NTIS ONLY
                        by the Rotating Biological Contactor  PB 231 892
                        Process: by F.L.Welsh, D.J.Stucky,
                        Autotrol Corp., Milwaukee, WI

 107.  EPA-670/2-74-075 *Surge Facility for Wet-  and Dry-      GPO
                        Weather Flow Control: by H.L.Wei born  EP 1.23/2:670/2-74-075
                        City of Rohnert Park, CA             NTIS
                                                              PB 238 905

 108.  EPA-670/2-74-079  An Evaluation of Three Combined       NTIS ONLY
                        Sewer Overflow Treatment AlteTna-     PB 239 115
                        tives: by J.W.Parks, et  al.,
                        £Tty~bf Shelbyville,  IL

 109.  EPA-670/2-74-086  Chemical Impact of Snow  Dumping       NTIS ONLY
                        Practices: by J.P.O'Brien, et al.,    PB 238 764
                        Arthur D. Little, Inc.,  Cambridge, MD

*Copies may be obtained from EPA Storm and Combined Sewer Section,
 Edison, NO 08817
                                        443

-------
 Ref.
 No.    Report  Number     Title/Author	Source

 110.   EPA-670/2-74-087  Assessment  and  Development  Plans  for   NTIS  ONLY
                        Monitoring  of prganics  in StormPB  238 810
                        Flows:  by A.Molvar, A. Tul niello,
                        Raytheon Co., Portsmouth, RI

 111    EPA-670/2-74-090  *Countermeasures for Pollution  from    NTIS
                        Overflows:  by R.Field,  USEPA.  and     PB  240 498
                        J.A.Lager,  Metcalf &  Eddy,  Inc.,
                        Palo Alto,  CA

 112.   EPA-670/2-74-096  Characterization  and  Treatment of     NTIS
                        Urban Land  Runoff; by Newton V.       PB  240 978
                        Colston, Jr., North Carolina State
                        University, Raleigh,  NC
 113.   EPA-670/2-75-002  *Suspended  Solids  Monitor:  by  John  W.   NTIS
                         Liskowitz,  et  al.,  American Standard   PB  241 581
                         Inc.,  New  Brunswick,  NJ

 114.   EPA-670/2-75-010  *Multi-Purpose  Combined Sewer  Overflow  NTIS
                         Treatment  Facility, Mt.  Clemens, MI:   PB  242 914
                         by V.U.Mahida,  F.J.DeDecker,  Spalding
                         DeDecker & Assoc.,  Madison Heights, MI

 115.   EPA-670/2-75-011  *Physical and Settling Characteristics  NTIS
                         of Particulars in  Storm and  Sanitary  PB  242 001
                         Wastewater; by R.J.Dalrymple.  et al,
                         Beak  Consultants  for  American  Public
                         Works  Assoc.,  Chicago, IL

 116.   EPA-670/2-75-017  *Stormwater Management Model User's    NO  NTIS
                         Manual-Version II:  W.C.Huber,  et al.,
                         University of  Florida, Gainesville, FL

 117.   EPA-670/2-75-019  *Biological  Treatment  of  Combined       NTIS
                         Sewer Overflow at Kenosha, WI:  by      PB  242 126
                         R.W.Agnew.et al.,  Envirex, Mil-
                         waukee, WI

 118.   EPA-670/2-75-020  *Sewage System  Monitoring and  Remote    NTIS
                         Control: by T.R.Watt. et al..  Detroit  PB  242 107
                         Metro  Water Department,  Detroit MI

 119.   EPA-670/2-75-021  *Bench-Scale High-Rate Disinfection    NTIS
                         of Combined Sewer Overflows:  by P.E.   PB  242 296
                         Moffa,  et  al.,  O'Brien & Gere  Engrs.,
                         Syracuse,  NY

 120.   EPA-670/2-75-022  *Urban  Stormwater Management Modeling   NTIS
                         and Decision-Making:  by  J.P.Heaney    PB  242 290
                         and W.C.Huber, University  of  Florida,
                         Gainesville,  FL

*Copies may be obtained  from EPA Storm  and Combined Sewer Section,
 Edison, NJ 08817

                                     444

-------
 Ref.
 No.    Report  Number      Title/Author	Source

 121.   EPA-670/2-75-035  Stream Pollution Abatement by Supple- NTIS ONLY
                         mental  Pumping:  by C.W.Reh and W.E.PB 239 566
                         Saddler,  City of Richmond, VA

 122.   EPA-670/2-75-041 *Storm Water Management Model: Pis-    NTIS
                         semination and User Assistance:PB 2242 544
                         J.A.Hagerman  and F.R.S.Dressier,
                         University City Science Center (UCSC),
                         Philadelphia, PA

 123.   EPA-670/2-75-046 *Rainfall-Runoff Relations on Urban    NTIS
                         and Rural  Areas: by E.F.Brater and    PB 242 830
                         J.D.Sherrill, University of Michigan,
                         Ann Arbor, MI

 124.   EPA-670/2-75-054  Characterization and Treatment of     NTIS ONLY
                         Combined  Sewer Overflows: by Engi-    PB 241 299
                         neering Science Inc. for City and
                         County of San Francisco, CA

 125.   EPA-670/2-75-065 *Short Course Proceedings, Application NTIS
                         of Stormwater Management Models:PB 247 163
                         F.DiGiano, et al./University of
                         Massachusetts, Amherst, MA

 126.   EPA-670/2-75-067 *Automatic Organic Monitoring System   NTIS
                         for Storm ana Combined Sewers: byPB 244 142
                         A.Tulumello,  Raytheon Co., Ports-
                         mouth, RI

 127.   EPA-440/9-75-004 *Water Quality Management Planning for NTIS
                         Urban Runoff: by G.Amy, et al.,PB 241 689
                         Woodward-Clyde, San Francisco, CA

 128.   EPA-600/2-75-004 *Contributioris of Urban Roadway Usage  NTIS
                         to Mater_Pollution: by D.G.Shaheen,    PB 245 854
                         Biospherics Inc., Rockville, MD

 129.   EPA-600/2-75-007  Impact of Hydro!ogic Modifications on NTIS
                         Water Quality: by J.Bhutani, et al..  PB 248 523
                         Mitre Inc., McLean, VA

 130.   EPA-600/2-75-027 *Sewer Flow Measurement-A State-of-    NTIS
                         the-Art Assessment: by P.E.Shelley    PB 250 371
                         and G.A.Kirkpatrick, EG&G Washington
                         Analytical Services Center, Inc.,
                         Rockville, MD

 131.   EPA-600/2-75-033 *A Treatment of Combined Sewer Over-   NTIS
                         flows by  Dissolved Air Flotations:    PB 248 186
                         by T.A.Bursztynsky, et al., Engineer-
                         ing Science Inc., Berkeley, CA

*Copies may  be obtained from EPA Storm and Combined Sewer Section,
 Edison,  NJ  08817
                                     445

-------
 Ref.
 No.    Report  Number      Title/Author	source

 132.   EPA-600/2-75-Q62  *The  Helical Bend  Combined  Sewer Over-  NTIS
                         flow Regulator: by  R.H.Sullivan,  et   PB  250 619
                         al.,  American  Public  Works Assoc.,
                         Chicago,  IL

 133.   EPA-600/2-75-065  *An Assessment  of  Automatic Sewer       NTIS
                         Flow Samplers-!975: by  P.E.ShelTey.    PB  250 987
                         EG&G Washington Analytical  Services
                         Center,  Inc.,  Rockville, MD

 134.   EPA-600/2-75-071  *Detention Tank  for  Combined Sewer     NTIS
                         Overflow: by Consoer, Townsend  and     PB  250 427
                         Associates, Milwaukee,  WI

 135.   EPA-600/2-76-006  *Design and Testing  of a Prototype     NTIS
                         Automatic Sewer Sampling System:       PB  252 613
                         by P.Shelley,  EG&G  Washington Analyt-
                         ical  Service Center Inc.,  Rockville, MD

 136.   EPA-600/2-76-058   Future Direction  of Urban  Water       NTIS ONLY
                         Models:  by M.Sonnen,  Water Resources   PB  249 049
                         Engineers  (WRE),  Walnut Creek,  CA

 137.   EPA-600/2-76-095  *Urban Runoff Pollution  Control         NTIS
                         Program  Overview: FY  76: R.Field,      PB  252 223
                         A.N.Tafuri, H.E.Masters, USEPA,       In-house
                         Edison,  NJ                             Report

 138.   EPA-600/2-76-105  *An Economic Analysis of the  Environ-   NTIS
                         mental Impact of  Highway Deicing: by   PB  253  268
                         D.M.Murray and U..F.W.Ernst,  Abt
                         Associates, Inc., Cambridge, MA

 139.   EPA-600/2-76-115  *A Passive Flow Measurement System     NTIS
                         for  Storm and  Combined  Sewer:PB  253 383
                         by K.Foreman,  Grumman Ecosystems  Corp.,
                         Bethpage, NY

 140.   EPA-600/2-76-116  *Urban Stormwater  Runoff Determination  NTIS
                         of Volumes and  Flowrates:  by B.C.Yen"  PB  253 410
                         and  V.T.Chow,  University of Illinois,
                         Urbana,  IL

 140a.  WPD 03-76-04     *Proceedings Urban Stormwater Manage-   NTIS
                         ment Seminars:  Atlanta, GA. Nov.  4-6.  PB  260 889
                         and  Denver, CO, Dec.  2-4,  1975,
                         Edited by Dennis  Athayde,  USEPA,
                         Water Planning Div.,  Washington,  DC

 141.   EPA-600/2-76-175a*Assessment of  Mathematical Models for  PTIS
                         Storm and Combined  Sewer Management:   ^B  259 597
                         by A.Brandstetter,  Battene, Pacific
                         Northwest Lab., Rich!and,  WA

*Copies may be obtained  from  EPA  Storm  and Combined Sewer Section,
 Edison, NJ 08817
                                    446

-------
 Ref.
 No.    Report  Number
                       Title/Author
Source
 142.   EPA-600/2-76-175b  Assessment of Mathematical  Models  for MTIS  ONLY
                         Storm and  Combined Sewer Management-  PB 258 644
                         Appendix:  by A.Brandstetter,  Battelle,
                         Pacific Northwest Lab., Rich! and,  WA

 143.   EPA-600/2-76-217a  Urban Runoff Characteristics-Vol .  I,  NTIS  ONLY
                         Analytical Studies: by H.C.Preul  and  PB 258 033
                         C.N.Papadakis, University of Cincin-
                         nati, Cincinnati, OH

 144.   EPA-600/2-76-217b  Urban Runoff Characteristics-Vol.  II, NTIS  ONLY
                         by H.C.Preul and C.N.Papadakis,       PB 258 034
                         University of Cincinnati, Cincinnati,
                         OH

 145.  EPA-600/2-76-145 *Methodo1ogy for the Study of Urban    NTIS
                         Storm Generated Pollution and Control :PB 258 743
                         by Envirex, Environmental Sciences
                         Division, Milwaukee, WI
146.  EPA-600/2-76-222a*Wastewater Management Program,
                        Jamaica Bay-Vol.I,  Summary Report:
                        by. D.L.Feurstein .and W.O.Maddaus,
                        City of New York, NY

147.  EPA-600/2-76-222b Wastewater Management Program,
                        Jamaica Bay-VoK II, Supplemental
                        Data, NYC Spring Creek:  by D.L.
                        Feurerstein and W.O.Maddaus,  City
                        of New York, NY

148.  EPA-600/2-76-218 *Deve]opment and Application of  a
                        Simplified Stormwater Management
                        Model: by Metcalf & Eddy.  Inc.  Palo
                              CA
149.  EPA-600/2-76-244 *Proceedings of Workshop on Micro-
                        organism in Urban Stormwater:
                        March 24,  1975, Storm and Comb i n ed
                        Sewer Section, USEPA, Edison,  NJ

150.  EPA-600/2-76-243 *Wastewater Flow Measurement in
                        Sewers Using Ultrasound, Milwaukee:
                        by R.J.Anderson and S.S.Bell,  City
                        of Milwaukee, WI

151.  EPA-600/2-76-271 *The Swirl  Concentrator for Erosion
                        Runoff Treatment:  by R.H. Sullivan,
                        et al . , American Public Works  Assoc.,
                        Chicago, IL

152.  EPA-600/2-76-242 *Development of a Hydrophobic Sub-
                        stance to  Mitigate Pavement Ice Ad-
                        fiesion: by B.H.Alborn and H.C.Poehl-
                        mann,  Ball  Bros.,  Inc., Boulder, CO
                                                               NTIS
                                                               PB 260 887
                                                               NTIS ONLY
                                                               PB 258 308
                                                               NTIS
                                                               PB 258 074
                                                               NTIS
                                                               Pending
                                                               NTIS
                                                               Pending
                                                               NTIS
                                                               Pending
                                                               NTIS
                                                               Pending
*Copies  may  be  obtained  from EPA Storm and Combined Sewer Section,
 Edison,  NJ  08817
                                    447

-------
Ref.
No.
       Report  Number      Title/Author
Source
153.  EPA-600/2-76-275 *Storm Water Management Model  Level  I
                        Preliminary Screening Procedures:
                        by J.P.Heaney, et al., University of
                        Florida, Gainesville, FL

154.  EPA-600/2-76-272 *Demonstration of Void Space Storage
                        with Treatment and Flow Regulation:
                        by Karl  R.  Rohrer Assocs., Inc.,
                        Akron, OH
155.  EPA-600/2-76-228
                         Demonstration  of Interim Techniques
                         for Reclamation  of Polluted Beach-
                         water:  by J.F.Weber,  City of Cleve-
                         TancTT OH
                                                               NTIS
                                                               PB 259 916
                                                               NTIS
                                                               Pending
NTIS ONLY
PB 258 192
156.
157.
158.
159.
160.
161.
       EPA-600/2-76-286 *Cost Estimating Manual—Combined      NTIS
                         Sewer Overflow Storage Treatment:      Pending
                         by H.H.Benjes, Jr.,  Gulp,  Wesner,
                         Gulp, Inc.,  El Dorado  Hills,  CA

                         Nationwide  Evaluation  of Combined      At  Printers
                         Sewer Overflows and  Urban  Stormwater
                         Discharges,  Vol.  II;  Cost  Assessment"
                         and Impacts:  by J.F.Heaney,  et a!.,
                         University  of Florida, Gainesville,  FL

                         Field Prototype Demonstration of the  DRAFT
                         Swirl Degritter:  by  R.H.Sullivan,  et
                         al., American Public Works Assoc.,
                         Chicago,  IL

                        *Handling  and  Disposal  of Sludges from At  Printers
                         Combined  Sewer Overflow Treatment-
                         Phase I  (Characterization):  by M.K.
                         Gupta, et al., Envirex, Environmental
                         Science Division,  Milwaukee,  WI

                         Microorganisms in Urban Stormwater:by DRAFT
                         V.P.Olivieri, et al.,  The  Johns
                         Hopkins  University,  Baltimore, MD
                         Assessment  of the Impact of the       DRAFT
                         Handling and  Disposal  of Sludges
                         An'sing  from  Combined  Sewer Overflow
                         Treatment:  by M.J.Clark and A.Geino-
                         polos, Envirex,  Environmental  Sciences
                         Division, Milwaukee, WI

 162-                     Swirl  Device  for Regulating and       At  Printers
                         Treating Combined Sewer Overflows.
                         EPA Technology Transfer Capsule
                         Report:  by  R.Field and H.E.Masters.
                         USEPA, Storm  and Combined Sewer Sec.,
                         Edison,  NJ

^Copies may  be obtained  from  EPA  Storm and Combined Sewer  Section,
 Edison,  NJ  08817
                                    448

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 Ref.
 No.    Report  Number      Title/Author	Source

 163.   EPA-600/2-77-033   Methods  for Separation  of Sediment    NTIS ONLY
                         from Storm Hater at ConstructionPending
                         Sites:  by J.F.Ripken,  et al.,  Univ.
                         of Minnesota,  Minneapolis, MM

 164.                     Nationwide Evaluation  of Combined     DRAFT
                         Sewer Overflows and Urban Stormwater
                         Discharges. Vol. Ill:  Characterization:
                         by R.H.Sullivan, et al., American
                         Public  Works  Assoc., Chicago,  IL

 165.                     Cost-Effective Pollution Control of   DRAFT
                         Combined Wastes and Urban Runoff: by
                         Clinton Bogert Assocs., Fort Lee, NO

 166.                     Analysis of Practices  for Preparing   DRAFT
                         an Economic Analysis and Determining
                         Infiltration  and Inflow: Vol.  II:
                         Manual  of Practice, Sewer System
                         Evaluation Rehabilitation and New
                         Construction: by R.H.Sullivan, et
                         al., American Public Works Assoc.,
                         Chicago, IL

 167.   EPA-440/9-75-001   Report  on State Sediment Control      NTIS
                         Institutes Program: USEPA, Office of  PB 241 088
                         Water Planning and Standards

 168.   EPA-600/8-76-001a Erosion and Sediment Control Audio-   NTIS
                         Visual  Training Program: Instruction  PB 256 901
                         Manual: by The State of Maryland
                         Water Resources Administration; Dept.
                         of Transportation, The Federal High-
                         way Administration; The U.S. Department
                         of Agriculture, Soil Conservation
                         Service; and  USEPA, Office of Research
                         and Development

 169.   EPA-600/8-76-001b Erosion and Sediment Control Audio-   NTIS
                         visual  Training Program: Workbook:    PB 258 471
                         by The  State  of Maryland Water Resources
                         Administration; Department of Transpor-
                         tation, The Federal Highway Adminis-
                         tration; The  U.S. Department of Agri-
                         culture, Soil Conservation Service;
                         and USEPA, Office of Research and
                         Development

 170.   EPA-600/2-77-015  *Treatment of  Combined  Sewer Overflows NTIS
                         by High Gradient Magnetic Separa-Pending
                         tion: by John Oberteuffer, et  al.,
                         Sal a Magnetics, Cambridge, MA

*Copies may  be obtained  from  EPA  Storm  and Combined Sewer Section,
 Edison,  NJ  08817
                                     449

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Ref.
No.    Report Number
Title/Author
Source
171.
172.
173.
174.
Cottage Farm Combined Sewer Detention NTIS ONLY
and Chi on'nation Station, Cambridge,  Pending
MA: by Commonwealth of MA Metropolitan
District Commission, Boston, MA
Bachman Treatment Facility for Ex-
cessive Storm Flow in Sanitary
Sewers: by H.W.Wolf, Texas A&M
University, for Dallas Water
Utilities, Dallas, TX
NTIS ONLY
Pending
Evaluation of Fluidic Combined Sewer  At Printers
Regulators Under Municipal Service
Conditions: by P.A.Freeman, Peter A.
Freeman Assoc., Inc., Berlin, MD
Catchbasin Technology Overview and
Assessment: by J.J.Lager, et al..
Metcalf & Eddy, Inc., Palo Alto, CA,
in association with Hydro-Research-
Science, Santa Clara, CA
At Printers
                                    450

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               ONGOING URBAN RUNOFF POLLUTION CONTROL PROJECTS
 Project
 Reference
 Number
                       On-Going Projects
 P-l



 P-2


 P-3



 P-4



 P-5




 P-6


 P-7


 P-8


 P-9


 P-10


 p-n


 P-12
"Nationwide Characterization, Impacts, and Critical Evaluation
of Combined Sewer Overflow, Stormwater, and Non-Sewered Urban
Runoff." American Public Works Association, 68-03-0283

"Disinfection/Treatment of Combined Sewer Overflows -
Syracuse, N.Y." Onondaga County, N.Y., 802400

"Development of a Swirl Concentrator and a Helical Combined
Sewer Overflow Dual Functioning Regulator-Separator."
American Public Works Association, 68-03-0272

"Demonstration of a Swirl Regulator/Solids Separator System
for Control of Combined Sewer Overflows." City of Lancaster,
Pennsylvania, 802219

"State-of-the-Art Update on Storm and Combined Sewer Overflow
Management and Treatment, and An Urban Planning Guide for the
Assessment of Storm Flow Pollution and the Selection of System
Pollution Control Methods." Metcalf & Eddy, Inc., 68-03-2228

"Use of Polymers to Reduce or Eliminate Sewer Overflows in the
Bachman Creek Sewer." City of Dallas, Texas, 11022 DZU

"Combined Sewer Fluidic Regulator Demonstration." City of
Philadelphia, 11022 FWR

"Development of a Flocculation-Flotation Module." Hercules,
Inc., 14-12-855

"Stormwater Treatment Facilities." City of Dallas, Texas,
11023 FAW

"The Lawrence Avenue Underflow Sewer System." City of Chicago
11022 EMD

"Microorganisms in Stormwater." John Hopkins University,
802709

"Nutrient Removal Using Existing Combined Sewer Overflow
Treatment Facilities." Onondaga County, N.Y., 802400
Note:   Number appearing in left margin corresponds  to  reference numbers
       cited in report text.
                                     451

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Project
Reference
Number
                       On-Going Projects
P-13


P-14



P-15


P-16


P-17



P-18



P-19



P-20



P-21


P-22



P-23



P-24


P-25


P-28


P-29


P-30
"Comparison of Alternate Sewer Design." City of Elizabeth
New Jersey, 802971

a) "Refine/Verify a Simplified Model to Handle Large Areas
with Minimal Data Input as a Planning Aid." Rochester Pure
Water Agency, Y-005141

b)  "Combined Sewer Overflow Abatement Program - Rochester,
N.Y." Rochester Pure Water Agency, Y-005141

"Maximum Utilization of Water Resources in a Planned
Community." Rice University, 802433

"Evaluation of Present Catch Basin Technology and Demonstration
and Evaluation of New Upstream Attenuator/Solids Separator
Design." Metcalf & Eddy, Inc., 68-03-0274

"Analysis of Practices for Preparing an Economic Analysis and
Determining Infiltration." American Public Works Association,
803151

"Engineering Aspects of Storm and Combined Sewer Overflow
Technology A Manual of Instruction." North Carolina State
University, 801358

"Develop a Movie on Nature/Impacts of Stormwater Pollution
As Compared to Other Forms of Water Pollution." (SRO ID
No. 61ABR), EPA, Technology Transfer

"Characterization and Disposal of Combined Sewer Overflow
Sludges and Solids." Envirex, 69-03-0242

"Development and Demonstration of Combined Sewage Treatment
Utilizing Screening and Spilt-Air Flotation-" City of
Milwaukee (Hawley Road) 11020 FDC

"Demonstration of Screening/Dissolved-Air Flotation as an
Alternative to Combined Sewer Separation."  City of Racine,
Wisconsin, 11023 FWS

"Sludge Treatment and Disposal Methods for Combined Sewer
Overflow." Envirex, 68-03-0242

"Demonstration Real-Time Automatic Control in Combined Sewer
System." City and County of San Francisco, California, 803743

"Evaluation of Stormwater Treatment Methods." Minnehaha
Creek Watershed District, 802535

"Evaluation and Technology Transfer of the Swirl Concentrator
Principle." American Public Works Association, 803157

"Demonstration/Evaluation of  Impregnated Concrete Pipe and
Other Methods of  Infiltration Control." Texas Water Quality
Board, 802651
                                     452

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Project
Reference
Number
                       On-Going_Projects
P-31


P-32


P-34



P-37



P-39



P-40


P-41


P-42



P-45


P-46


P-49


P-50




P-51


P-53


P-68


P-70


P-71
"Trenchless Sewer Construction and Sewer Design Innovation."
Sussex County Council, Delaware, 800690

"The Somerville Marginal Conduit Including Pretreatment
Facilities." Boston Metropolitan District Commission, 11023 DME

"Large Scale Demonstration of Treatment of Storm-Caused Over-
flows by the Screening Method." City of Fort Wayne, Indiana,
11020 GYU

"Boston University Bridge Storm Water Detention and
Chlorination Station."  Boston Metropolitan District
Commission, 11023 FAT

"Ultra-High Rate Filtration of Combined Sewer Overflow and Raw
Dry Weather Sewage at Newtown Creek Sewage Treatment Plant."
City of New York, 803271

"East Chicago Treatment Lagoon." East Chicago Sanitary
District, 11020 FAV

"Evaluation of Various Aspects of an Aluminum Storm Sewer
System." City of LaSalle, Illinois, 11032 DTI

"Pilot Plant Studies to Determine the Feasibility of Using
High Gradient Magnetic Separation (HGMS) for Treating Combined
Sewer Overflows." Sala Magnetics, Inc., 68-03-2218

"Development of Electromagnetic Flowmeter for Combined Sewer."
Cushing Engineering, Inc., 68-03-0341

"Efficiency of Off-Stream Detention-Retention Measures as
Sediment Control Devices." Howard University, 803066

"Collect and Define Availability of Test Data (Rainfall/Runoff)
For Urban Models-Data Base." University of Florida, 68-03-0496

"Develop.and Demonstrate New and.. .Improved Model for Design
of Combined Sewers to Prevent Solids Sedimentation and to
Optimize Construction Cost." Water Resources Engineers, Inc.,
68-03-2205

"Short Course on Application of Stormwater Management Models-
1975." University of Massachusetts, 803069

"A Guide for Comprehensive Planning for Control of Urban Storm
and Combined Sewer Runoff." University of Florida, 802411

"Verification of Water Quality Impact from CSO using Real-Time
Data." County of Milwaukee, 804518

"Optimization and Testing of Highway Materials to Mitigate Ice
Adhesion." Washington State University, 804660

"Evaluation and Technology Transfer of the Swirl Concentrator
Principal." American Public Works Association, 803157
                                     453

-------
Project
Reference
Number
                       On-Going Projects
P-66



P-67



P-72


P-73


P-74
"Characterization of Solids Behavior in, and Variability
Testing of Selected Control Techniques for Combined Sewer
Systems." Northeastern University, 804578

"Demonstration of Non-Point Pollution Abatement through
Improved Street Cleaning Practices." San Jose, California,
804432

"Demonstration of Erosion and Sediment Control Technology."
State of California, 803181

"Methods of Separation of Sediment From Storm Water at
Construction Sites." University of Minnesota, 803579

"Demonstration and Evaluation of Sediment and Erosion Control
Techniques Applicable to the S.E.  Piedmont, Fairfield County,
South Carolina." University of South Carolina, 803724
                                     454

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           OTHER  URBAN  RUNOFF  POLLUTION  CONTROL  PROGRAM  REFERENCES
Ref.
No.	References	

R-l     Total  Urban  Pollutant Load:   Sources  and Abatement Strategies:   Enviro
       Control,  Inc.,  for Council  of Environmental  Quality,  Draft Report,
       October 1973.

R-2    Sources of Metals  in New York City Wastewater:   Larry A.  Klein,  et  al
       JWPCF, Vol. 46,  No.  12, December 1974.

R-3    Water  Quality  Effects From  Urban Runoff:  Robert E.  Pitt  and Richard
       Field, Preprint,  1974 American Water  Works Association Conference,
       Boston, Massachusetts.

R-4    1974 Survey  of Needs for Municipal Wastewater Treatment Facilities:
       USEPA, Office  of  Water and  Hazardous  Materials,  Washington,  D.C.

R-5    Report to National  Conmission on Water Quality on Assessment of  Tech-
       nologies  and Costs for Publicly owned Treatment Works under  Public"
       Law 92-500,  Volume TlMetcaTf& Eddy, Inc., September 1975.

R-6    Study  and Assessment of the Capabilities and Cost of Technology  for
       Control of Pollutant Discharges from  Urban Runoff:Black, Crow  &
       Eidness,  Inc.  and Jordan, Jones & Goulding, Inc., for the National
       Conmission on  Water Quality, Draft Report, July 1975.

R-6a   Management and Control of Combined Sewer Overflows:   Richard Field  and
       E.J. Struzeski, Journal Water Poll. Control  Fed., Vol. 44, No. 6,
       July 1972, pp  1393-1415.

R-6b   Combined Sewer Overflows:  Richard Field,  Civil  Engineering  - ASCE
       Magazine, February 1973, pp 57-60.

R-6c   Coping with  Urban Runoff in The United States:   Richard Field, Water
       Research, Vol.  9,  Pergamon  Press 1975, pp  499-505.

R-6d   Urban  Runoff Pollution Control - State of  The Art:  Richard  Field and
       John A. Lager, Journal of the Environmental  Engineering Division, ASCE,
       Vol. 101, No.  EE1, Proc. Paper 11129, February 1975,  pp 107-125.

R-6e   Urban  Runoff Must  Be Controlled:  Richard  Field, Baltimore Engineer
       Magazine, March 1975.

R-6f   Literature Review  - Urban Runoff and  Combined Sewer Overflow: Richard
       Field  and Pauline  Weigel, Journal  Water Pollution Control Federation,
       Vol. 45,  No. 6, June 1973,  pp 1108-1115.

Note:   Number appearing  in left margin corresponds to reference  numbers
       cited  in  report text.
                                     455

-------
     OTHER URBAN RUNOFF POLLUTION CONTROL PROGRAM"REFERENCES (continued)


Ref.
                                      References
R-6g   Literature Review - Urban Runoff and Combined Sewer Overflow:   Richard
       Field and Pamela Szeeley, Journal  Water Pollution Control  Federation,
       Vol.  46, No.  6,  June 1974, pp 1209-1226.

R_6h   Literature Review - Urban Runoff and Combined Sewer Overflow;   Richard
       Field and Donna  Knowles,  Journal Water Pollution Control  Federation,
       Vol.  47, No.  6,  June 1975, pp 1353-1369.

R-6i   Literature Review - Urban Runoff and Combined Sewer Overflow:   Richard
       Field, J. Curtis, and R.  Bowden, Journal  Water Pollution  Control
       Federation, Vol.  48, No.  6,  June 1976, pp 1191-1206.

R-7    Stormwater Pollution Control:  A New Technology:  Richard  Field and
       Anthony N. Tafuri, 28 Minute - 16 mm - Sound - Color Film, Available
       from:  General Services Administration, National Archives  and  Records
       Service, National Audiovisual Center, Washington, D.C.   20409,
       Rental - $12.50,  Purchase -  $119.50.

R-8    Areawide Assessment Procedures Manual:  Hydroscience,  Inc.,  USEPA,
       Chapters 2 & 3,  and Appendix I, Cincinnati,  OH, September  1976.

R-9    Generalized Computer Program, Urban Storm Water Runoff, STORM:
       Hydrologic Engineering Center for U.S. Army, Corps of  Engineers,
       723-S8-L2520, October 1974.

R-10   A Model for Evaluating Runoff-Quality in  Metropolitan  Master Planning:
       L.A.  Roesner. gt al, Water Resources Engineers, A.D.  Feldman,  The
       Hydrologic Engineering Center, for U.S. Army, Corps of Engineers, A.O.
       Fried!and, Department of  Public Works, City  of San Francisco,  Tech-
       nical Memorandum No. 23,  ASCE, April 1974.

R-ll   Water Pollution  and Associated Effects From Street Salting:   Richard
       Field, Edmond J.  Struzeski,  Jr., Hugh Masters, Anthony Tafuri,
       Journal of the Environmental Engineering Division, ASCE,  Vol.  100,
       No. EE2, Proc.  Paper 10473,  April 1974, pp 459-477.

R-12   Community Action Guideline for Soil Erosion and Sediment Control:
       National Association of  Counties Research Foundation,  March 1970.

R-13   Standards and Specifications for Soil Erosion and Sediment Control  in
       Developing Areas:The United States Department of Agriculture, Soil
       Conservation Service for The State of Maryland, June 1975.

R-14   Infiltration - Inflow Analysis:  David J. Cesareo and Richard  Field,
       Journal of The Environmental Engineering Division, ASCE,  Vol.  101,
       No. EE5, Proc.  Paper 11645,  October 1975, pp 775-785.

R-15   Design of a Combined Sewer Overflow Regulator/Concentrator:   Richard
       Field, Journal  Water Pollution Control Federation, Vol.  46, No. 7,
       July 1974, pp 1722-1741.

R-16   Give Stormwater  Pollutants the Spin:  Richard Field, et al_, The
       American City &  Country  Magazine, April 1976, pp 77-78.


                                      456

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                               PLANNED WASTEWATER REUSE
                                 A LITTLE-USED RESOURCE
                                     F.  M.  Middleton
                                  Senior Science Advisor
                      Municipal Environmental Research Laboratory
                              Environmental  Research Center
                           U.S. Environmental Protection Agency
                                  Cincinnati,  Ohio 45268
                                        ABSTRACT


      Water reuse is a common fact of  life.   Water shortages and the recent recognition
in the United States of the need to conserve  water has focused attention upon the value of
more intentional reuse.  Planners recognize the  need for a hierachy of water use in the
community.  All water need not be of the same quality.   And the wastewater of a community
should be considered a resource.

      Wastewater reuse is being specifically recognized by recent legislation.  Public
Law 92-500, the "Federal Water Pollution Control Act Amendments of 1972", calls for re-
search and facilities construction to permit  reuse.   Public Law 93-523, the "Safe Drinking
Water Act", passed in December, 1974 allows for  grants to investigate and demonstrate
health implications involved in reclamation,  recycling and reuse of wastewater to prepare
a safe and acceptable drinking water.   The American Water Works Association and the Water
Pollution Control Federation has issued a joint  statement in support of appropriate reuse.

      Municipalities on an annual basis use  about 4 X 10  m  (10 trillion gallons) of
water and wastewater return amounts to  3 X 10^°m^ (8 trillion gallons).  Present wastewater
                                                                                Q -3
usage for specific purposes such as irrigation and cooling amount to only 5 X 100m°
(13 billion gallons) or less than 2% of the available flow.  Much of the waste flow
can be put to productive use.

      A great deal of research in EPA  is directed toward some facet of wastewater reuse.
A major effort is now needed to embark  upon a long-term integrated program to permit waste-
water reuse for any purpose including to supply  drinking water.   Some states and major
municipalities are already working on a variety  of reuse projects.  Our combined programs
should lead us to a sound base of science and technology that will ensure safety and gain
the public confidence for full-scale water reuse.   The technology for preparing water of
any quality is well advanced.  Needed is better  knowledge on the level of residues that
remain and their possible health effects.  Social and economic factors will need addition-
al research.


              INTRODUCTION                    years. Severe contamination of many surface
                                              supplies has occurred. Increasing instances
      Abundant supplies of clean surface      of groundwater contamination are being found.
and underground waters in the United States    Thus,  our relatively fixed volume of water
have been taken for granted until recent       may become less and less usable.  Adequate
                                           457

-------
pollution control measures must be taken
and conservation and reclamation of
resources must become the rule.

      Water has always been used and reused
by man.  The natural water cycle, evapor-
ation, and precipitation is one of reuse.
The return of wastewaters to the streams
and lakes of the country is a fact of life.
The unplanned reuse of wastewaters is not
new.  The planned reuse of wastewaters  for
beneficial purposes has been done in some
areas for many years, but it is here that
we need to concentrate our efforts for  far
greater use of our wastewaters.

      The quality and quantity of waste-
waters produced by the community depend
upon such factors as the source of supply,
population density, industrial practices,
and even the attitudes of the local popu-
lation.  The quality of the environment can
be improved by reducing pollution at the
source, providing adequate treatment of the
wastewaters, and by recycling and reusing
wastewater.  Public support and some change
in social behavior will be required in  most
instances.

                DEFINITIONS

      Since there are many different types
of wastewater reuse and the term "reuse"
has different meanings to different people,
the following definitions will be used  for
this Workshop:

      Municipal Wastewater - The spent  water
of a community, consisting of water-carried
wastes from residences, commercial build-
ings, and industrial plants and surface or
groundwaters that enter the sewerage  system.

      Advanced Waste Treatment - Treatment
systems that go beyond the conventional
primary and secondary processes.   Advanced
waste treatment systems may include bio-
logical processes,  the use of  chemicals,
activated carbon,  filtration or separation
by membranes.

      Indirect Reuse -  Indirect reuse of
wastewater occurs  when water  already  used
one or more times  for domestic or  industrial
purposes is discharged  into  fresh  surface or
underground waters  and  is  used again  in its
diluted  form.

      Direct Reuse  - The planned  and  deli-
berate use of treated wastewater  for  some
beneficial  purpose such as irrigation, re-
creation, industry,  prevention of salt
water  intrusion by recharging of under-
ground aquifers, and potable reuse.

   Potable  reuse can be further divided
into two categories  as follows:

   Indirect Potable  Reuse *- The planned
addition of treated  wastewater to a drink-
ing water reservoir, underground aquifer,
or other body  of water designed for potable
use that provides a  significant dilution
factor.

   Direct Potable Reuse - The planned
addition of treated  wastewater to the head-
works  of a  potable water treatment plant or
directly into  a potable water distribution
system.

   OFFICIAL SUPPORT  FOR WASTEWATER REUSE

   The role of  the U.S.  Environmental Pro-
tection Agency  (USEPA)  and its predecessor
organizations  in wastewater reuse has been
stated in various acts.   Public Law 87-88
passed in 1961  amending the Federal Water
Pollution Control Act  directed the Secre-
tary (at that time of  Health,  Education,
and Welfare) "to develop and demonstrate
practicable means of treating municipal
sewage and  other water-borne wastes to
remove the  maximum possible amount of
physical, chemical,  and biological pollu-
tants  in order  to restore and maintain the
maximum amount  of the  Nation's water at a
quality suitable for repeated reuse."

   This Act gave impetus to the Advanced
Waste  Treatment Research Program, which
began  in 1960.   The objective of this
national program is  to conduct research
that will develop new  and improve existing
wastewater  treatment processes and ultimate
disposal technology, thus permitting maxi-
mum removal of contaminants and repeated
reuse  of the Nation's  waters.

   Public Law  92-500,  the "Federal Water
Pollution Control Act  Amendments of 1972",
recognizes  the potentially large benefit to
be realized if wastewaters can be renovated
for reuse applications.   Sections 201  (b),
201  (d), and 201 (g) (2)  (B) clearly require
1. that EPA provide  for the application of
best practicable waste treatment technology/
including reclaiming .and recycling of water;
                                            458

-------
2. that construction of revenue producing
facilities providing for reclaiming and
recycling be encouraged; and 3. that works
proposed for grant assistance, to the extent
practicable, allow for the application of
technology at a later date which will provide
for reclaiming and recycling of water.
Section 105 (a) (2) authorizes EPA to make
grants for demonstrating advanced waste
treatment and water purification methods,
and Section 105 (d) (2) requires that the
Administrator conduct on a priority basis
an accelerated effort to develop, refine,
and achieve practical application of advanc-
ed waste treatment methods for reclaiming
and recycling water and confining pollutants.

     The Safe Drinking Water Act of 1974
(Section 1444) also contains mandates of
importance with regard to renovation and
recycling of wastewaters.  Section 1444
authorizes a development and demonstration
program to: demonstrate new or improved
technology for providing safe water supply
to the public; investigate and demonstrate
health implications involved in the recla-
mation, recycling and reuse of wastewaters
for the preparation of safe and acceptable
drinking water.

     There exists, therefore, a strong and
clear legislative mandate for research
development and demonstration of reliable,
cost-effective technology for reclaiming
and recycling wastewaters for beneficial
uses.  A major beneficial use is the
supplementation of domestic water supplies.

     The Water Pollution Control Federa-
tion  (WPCF) (1) and the American Water Works
Association (AWWA) issued a joint resolution
that urged the Federal Government to support
a massive research effort to develop needed
technology.  These organizations underscored
the "lack of adequate scientific information
about possible acute and long-term effects
on man's health from such reuse", and also
noted that "the essential fail-safe tech-
nology to permit such direct reuse has not
yet been demonstrated."  The resolution
recognizes the need for an "immediate and
sustained multi-disciplinary, national
effort to provide the scientific knowledge
and technology relative to the reuse of
water for drinking purposes in order to
assure full protection of the public health."

     The USEPA in a policy statement on
water reuse dated July 7, 1972,  supports
and encourages  the  development and practice
of successive wastewater reuse.   EPA does
not currently support the direct inter-
connection of wastewater reclamation plants
with potable water  systems.

   SPECIFIC CONSIDERATIONS GOVERNING REUSE

      The reuse of  treated effluents is most
applicable where  large volumes of water are
used and the wastes are not highly contami-
nated.  The location of the treatment plant
and the possible  transport of the renovated
water are important considerations.   A
wastewater renovation plant need not always
be located at the same place as  the  munici-
pal wastewater  disposal plant, nor should
the renovation  process be dependent  upon
treating the total  flow.   Treatment  process-
es work most efficiently and economically
when dealing with a steady flow  of waste-
water rather than with the irregular flow
normally experienced from urban  sources.
This condition  can  be obtained by withdraw-
ing only a part of  the urban wastewater;
this is depicted  in Figure 1,  which  shows
how water renovation and reuse can be plan-
ned to best advantage  in  the community.

          VOLUME  OF  WASTEWATERS
       AVAILABLE  IN  MUNICIPALITIES

      Municipalities on an annual basis  use
about 4 X 10lOm3  (10 trillion  gallons) of
water, and wastewater return amounts to
3 X 1010m3(8 trillion gallons).   Present
wastewater usage  for specific  purposes is
shown in Table  1.

      As can be seen from the  Table, only
5 X 108m3 (136  billion gallons),  or  less
than 2% of the  available flow, is used on a
planned basis.  Much of the  waste flow can
be put to productive use.   Such  uses can go
a long way in conserving scarce  clean water
sources.

       STANDARDS  FOR WASTEWATER  REUSE

      To ensure the safety of water  supplies,
standards have  to be applied.   Standards for
drinking water  have been available for many
years.  Although  national standards  may be
set for drinking  water, the qualities of
river-water, industrial effluents, and re-
used wastewater are the responsibility of
the local controlling authority.  Even so,
the standards set must take into account
                                           459

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        DISCHARGE OF
     HOUSEHOLD SEWAGE
                                                DISCHARGES
                                              OF INDUSTRIAL
                                            WASTES UNSUITABLE
                                             FOR RECLAMATION
TRUNK
SEWER
EVEN  FLOW
 TO PLANT
                  WASTEWATER
             RENOVATION  PLANT
                                      SLUDGES
                                      RETURNED
                                      TO SEWER
                            -*-CLEAN WATER FOR  REUSE
                                                                       TO  MUNICIPAL
                                                                      DISPOSAL  PLANT

The diversion of  wastewater from  the trunk sewer to the wastewater renovation  plant

should be chosen at a point where it is  known  that the trunk sewer contains only household
                FIGURE  1. Simplified Wastawafer Reuse Scheme
   *From World Health Organization  Technical Report No. 517  (1973)
                     TABLE 1.  WATER REUSE IN THE UNITED STATES**
Type
Irrigation and agriculture
Industrial
Recreational
Non-potable domestic
:Groundwater augmentation
Volume
m3
3 X 108
2 X 108
11 X 106
< 4 X 106
< 4 X 106
in 1971
billion gals
77
54
3
< 1
< 1
No. of Plants
338
14
5
1
8
       *Estimated from information in  EPA publication EPA-660/2-73-006b
       "Wastewater Treatment and Reuse by Land Application" - Vols. I & II

      **From World Health Organization Technical  Report No. 517   (1973)
                                            460

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the possible transport of pollutants across
state borders or the effects  of discharges
on downstream water users.  Standard setting
is a most difficult and  critical job,  with
important economic implications.  Standards
must be  given the force  of  law, and an
authority must be created to  ensure that
they are observed.

      Standards governing the quality of
water in rivers and lakes are becoming
common.  Some countries  have, and others
are formulating, standards  applicable di-
rectly to effluents, though few countries
yet have standards for the  planned reuse of
treated  wastewater.  As  wastewater reuse
grows, it is important that standards be
set for  specific reuse purposes.

      As wastewater - treated or untreated -
has been reused in agriculture for a fairly
long time,  some countries have developed
standards for this purpose. A summary of
some representative standards for the use
of renovated water in agriculture is given
in Table 2.

             DOMESTIC REUSE

      In any reuse application there are a
number of points to consider.  One very
important question is whether the reuse
will result in multiple  recycle.  Multiple
recycle  produces a buildup  of refractory
materials,  especially inorganic ions,  and
may require the use of demineralization or
other specialized processes.  In-plant reuse
of industrial water, where  actual consump-
tion is  small, may lead  to  a  high degree of
recycle.  On the other hand reuses of muni-
cipal wastewater, except for  domestic reuse,
probably would not lead  to  multiple recycle.
Even in  the case of domestic  reuse there is
not likely  to be total recycle.  The reason
is that  less water is ordinarily found arriv-
ing at the wastewater treatment plant than
is supplied to the municipal  water system.
Such losses do occur and are  quite large in
warm, dry areas where domestic reuse is
likely to be most widely practiced.   In the
United States it is estimated (2)  that these
losses range from less than 20% in humid
areas to about 60% in arid  areas.  Parkhurst
et al.,  (3) point out, based  upon experience
in the Los Angeles area, that less than 50%
of a water  supply would  be  available for
reuse.   The disadvantage of these large
losses is the need for a substantial addi-
tional fresh water source.  The advantage
 is that the steady state mineral concentra-
 tion is reduced.  As a result, the degree of
 demineralization may be reduced substantial-
 ly below that needed if there were no loss-
 es.  Also, there is the flexibility of de-
 mineralizing either the renovated wastewater
 or the supplementary water source, there may
 be advantages to demineralizing the supple-
 mentary source.

       Another consideration in reuse is the
 character of the wastewater entering the
 treatment plant, especially with respect
 to industrial pollutants.  Care must be
 used to exclude materials that would be
 detrimental to the reuse application. This
 is especially true for domestic reuse, but
• also applies to less sophisticated reuse
 applications.  These materials may not be
 those usually considered toxic.  Ordinary
 salt brines would be undesirable, for
 example, if demineralization were being
 carried out on the renovated wastewater.
 In Los Angeles County, a survey of the
 sewer systems has been made to determine
 how much of the available wastewater has
 potential for reuse.  Waters having heavy
 metal contamination or high total dissolved
 solids were considered unacceptable.  A
 similar survey will be necessary for other
 municipalities planning extensive reuse.

       Another point that must be considered
 is distribution of the renovated water.   A
 multiplicity of piping systems, each one
 containing a different quality renovated
 water, will not usually be practical. There
 may be a number of large consumers in the
 vicinity of the treatment .plant.  This
 would make distribution simple and inexpen-
 sive.  If the consumers are widely distri-
 buted, however, one piping system in addi-
 tion to the existing municipal water system
 is almost certain to be the most that will
 be economically realistic.  The result is
 that the renovated wastewater must be of a
 quality to satisfy most of the customers
 without additional treatment.  Treatment
 such as those necessary for boiler water
 feed would be excluded, since present
 practice in water supply has shown that
 those treatments are more appropriately
 carried out by the user.

              INDIRECT REUSE

       The following discussion of indirect
 reuse taken in part from a World Health
 Organization publication  (4) is appropriate.
                                           461

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      Examples of indirect reuse in  certain
rivers:

      A study of a number of rivers  in
  the USA, carried out  in 1961 (5) showed
  that at periods of low flow 3.5-18.5%
  of the water had passed through domestic
  waste  systems.  If the volume of indus-
  trial  effluents is also taken into
       account, it would be expected that 20-40%
       of the river water at low flow in some
       areas may be reused water.

           Zoeteman in a World Health Organi-
       zation publication  (6) has plotted the
       percent of river flow used for community
       water supply versus the average yearly water
       flow for 89 rivers, Figure 2.  As might be
   TABL6 2.  EXISTING STANDARDS GOVERNING THE USE OF RENOVATED
              WATER IN AGRICULTURE'
                 California
Israel
South Africa
Federal Republic
  of Germany
Orchards and
/ineyards
Fodder,
-fibre crops,
and seed
crops
Crops for
human con-
sumption that
w/ll be pro-
cessed to Kill
pathogens
Crops for
human con-
sumption in
a raw state
Primary effluent;
no spray irrigation ;
no use of dropped
fruit
Primary effluent ;
surface or spray
irrigation.
For surface irriga-
tion, primary
effluent.
For spray irrigation,
disinfected sec-
ondary effluent (no
more than 23 coli-
form organisms per
100 mi).
For surface irriga-
tion, no more than
2.2 coliform organ-
isms per ICO ml.
For spray irrigation,
disinfected, filtered
waste water with
turbidity of 10 units
permitted, provid-
ing it has been
treated by coagula-
tion.
Secondary
effluent.
Secondary effluent,
but irrigation of
seed crops for
producing edible
vegetables pot
permitted.
Vegetables for hu-
man consumption
not to be irrigated
with renovated
wastewater unless
it has been properly
disinfected (< 1000
coliform organisms
per 100 ml in 80% of
samples).
Not to be irrigated
with renovated
wastewater unless
they consist of
fruits that are peel-
ed before eating.
Tertiary effluent, No spray irrigation
heavily chlorinated in the vicinity.
where possible. No
spray irrigation.
Tertiary effluent. Pretreatment with
screening and
settling tanks.
For spray irrigation,
biological treatment
and chlorination.
Tertiary effluent. Irrigation up to
4 weeks before
harvesting only.
Potatoes and
cereals— irrigation
through flowering
stage only.
*From World Health Organisation Technical  Report No. 5l7 (1973)
                                       462

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Fig. 2 RELATION BETWEEN AVERAGE YEARLY WATERFLOW AND
      %  RIVER WATERFLOW USED FOR  COMMUNITY WATER
      SUPPLY  FOR  89 RIVERS  IN THE WORLD IN 1968-1972
     10000-
  o
  o
  e
  £t

  V
      1000.
       10O'
        1 0
        01
            TUGELA i s AFRICA i
          001
                       01
                                      • RHINE ( NETHERLANDS )
                                    > DANUBE ( HUNGARY )
                                            •COLORADO (USA)

                                               I
                                           • MURRAY (AUSTRALIA )
  • THAMES
   (UK)
                                                    e TECS
                                                     (UK)
-JAJRUO
 ( IRAN )
 . •
                                               10
          100
          V. RIVER WATERFLOW USED  FOR  COMMUNITY  WATER  SUPPLY
         (Zoeteman. 1975)
                            463

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expected, the rivers with low flow show the
greatest percentage use. In the future, the
trend-line of Figure 2 will most likely move
upward to the higher river flow values.   It
is important to know the amount of present
reuse and to forecast for future reuse.   A
case in point is the Great Ouse River at
Clapham, Untied Kingdom where the present
and future content of effluent has been
tabulated, Table 3.

      The Ruhr River in Germany has a re-
use factor of 36% half of the time and has
reached 86% under severe conditions.  At
the 86% concentration of effluent it was
reported that 7% of the population of Essen,
Germany had non-bacterial gastroenteritis.

      As treatment of wastewaters improves
future effluents will be less damaging to
water quality.

      In the United Kingdom, the River
Thames, which provides two-thirds of the
water supply for the Greater London area,
contains about 14% of sewage effluent when
flowing at an average rate.  During the
severe drought of 1975 the flow in the
Thames dropped from a daily volume of
35 m3/s (1,283 ft3/s) to 2.2 m3/s (77 ft3/s)
and the flow was, no doubt, nearly all efflu-
ent.  In times of drought, the water supply
source for Agra, India consists almost en-
tirely of partially treated sewage from New
Delhi, 190 km away.
      The Mardyke is a small river rising to
 the  east of London and discharging into the
 Thames  estuary.   It has a dry-weather flow
 of about 0.2 m3/s (7 ft3/s).   The Essex
 River Authority  has devised a scheme  where-
 by about 0.4 m3  (14 ft3/s)  per day of sand-
 filtered secondary effluent from the  River-
 side wastewater  treatment plant will  be
 pumped  into the  headwaters of the Mardyke
 to supplement the flow, instead of being
 discharged  direct to the estuary as at
 present.  The mixture of river water  and
 effluent will be available for abstraction
 under license by agricultural users in the
 middle  reaches and by industry at the lower
 reaches-an  area  now suffering from a  short-
 age  of  water owing to saline  intrusion into
 the  wells that provide much of the supply.
 A further supply of sand-filtered effluent
 will be made available for  direct industrial
 use.

      The  River Authorities  in the United
 Kingdom,  according to Billington (7) have
 formulated  a guideline that suggests a
maximum limit of 75% sewage effluent  in
rivers.

  In the  treatment of polluted rivers, the
 methods employed at  present are based upon
          TABLE 3.   ESTIMATED CONCENTRATION OF EFFLUENT IN GREAT OUSE RIVER


                                                % Concentration of Effluent

                                                               40

                                                               60

                                                               75

                                                               80
                                             464

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those developed over the years for the
treatment of relatively unpolluted river
water, and it appears that sufficient note
may not have been taken of the increasing
proportion of wastes in many rivers.

    The inadequacy of these traditional
methods may perhaps be indicated by the out-
breaks of infectious hepatitis in New Delhi
in 1955-56 [Dennis (8); Viswanathan  (9)],
when there were 30,000 cases, and in 1958.
The waterworks in question was of modern
design and, though there may have been some
faults in operation, they were of the sort
that may occur at any waterworks.  However,
at the time of the outbreak drought condi-
tions prevailed, and the water abstracted
from the river was estimated to contain
about 50% of sullage water.

    It appears, therefore, that the public
health aspects of the production of potable
water from polluted rivers should be review-
ed.  When rivers contain a high proportion
of effluent, the production of water from
them should be regarded as analogous to the
direct recovery of water from a sewage or
industrial effluent, and safeguards appro-
priate to this situation should be imposed.

    There is also an increasing need to
consider the optimum distribution of puri-
fication between the wastewater treatment
plant, the river itself  (self-purification),
and the treatment plant that produces pot-
able water.  There are two extreme cases:

     (a)  Wastewater is discharged with
    little or no treatment, all the
    purification occurring in the river
    or at the water treatment plant.
    This practice has been common in
    the past but is rapidly disappear-
    ing.  In fact, raw sewage disposal
    into rivers is prohibited in some
    countries.  Local authorities are
    requiring secondary treatment and,
    in some cases, the removal of the
    nutrients, phosphorus and nitrogen,
    because incidental pollution that
    is as yet uncontrolled may well
    use up the natural purifying
    capacity of the river.

     (b)  The wastewater is purified to
    a standard as high as that of the
    river water into which it is dis-
    charged, so that the type and degree
    of purification required at the water
       treatment plant is no different
       from that which would be required
       in the absence of the wastewater
       discharge.

       Almost certainly the optimum solution
 lies  somewhere between these two extremes,
 and optimization studies are required to
 determine it,  taking into account all the
 costs and benefits involved.  This may be
 difficult in practice because some of the
 social costs and benefits cannot readily
 be  expressed in economic terms.   Such
 optimization studies are likely  to be
 most  successful in the context of a single
 river basin authority having control over
 the treatment and discharge of wastewaters
 and also over  the abstraction and treatment
 of  potable waters.

       The unintentional reuse of wastewater
 also  occurs widely as a result of the use
 of  river water for agriculture,  recreation,
 and industrial supply and for these pur-
 poses,  too,  there is a need for  appropriate
 safeguards.

               DIRECT REUSE

       The only known case in the United
 States  where treated municipal effluent is
 used  for a domestic purpose is at the Grand
 Canyon  where the treated effluent is used
 for toilet flushing and other n