PB-240 005
DEMONSTRATION  OF  A  HIGH-RATE  ACTI-
VATED SLUDGE SYSTEM
Elmer L.  Miller
Engineering-Science,  Incorporated
Prepared for:


National Environmental  Research Center



March  1975
                             DISTRIBUTED BY:
                             National Technical Information Service
                             U. S. DEPARTMENT  OF COMMERCE

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 REPORT NO.

 EPA-670/2-75-037
 TITLE AND SUBTITLE
 DEMONSTRATION OF
 SLUDGE SYSTEM
                           2.
A HIGH-RATE ACTIVATED
5. REPORT DATE
March 1975-Issuing Date
                                 6. PERFORMING ORGANIZATION CODE
 AUTHOR(S)
 Ching H.  Huang.t Donald L.  Feuerstein,t and
 Elmer L.  Millerf
                                 8. PERFORMING ORGANIZATION REPORT NO.
. PERFORMING ORG "VNIZATION NAME AND ADDRESS
^Engineering-Science,  Inc.,Berkeley,  Californ-
  ia 94710
tcity of Chino,  Chino,California  91710
                                                      10. PROGRAM ELEMENT NO.
                                                     1BB043
                                           SR.  Task  007
                                           'GRANT NO7
                                                         WPRD 16-01-67
12. SPONSORING AGENCY NAME AND ADDRESS
 National Environmental Research  Center
 Office  of Research and Development
 U.S. Environmental Protection Agency
 Cincinnati,  Ohio  45268
                                  13. TYPE OF REPORT AND PERIOD COVEH&O
                                  14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
     A high-rate activated sludge  system was designed, constructed  and operated at the
3ity of Chino as a biological treatment system utilizing the maximum growth-rate
>otential of activated sludge as a means of removing organic, and possibly. inorganic,,
naterials from domestic wastewater.
     Operating results indicate  that  full-scale systems can be operated at high growth
rates and high substrate loading rates with concomitant high substrate removal
/elocities and high quality effluent.  Substrate loading rates as high as 3»6'(rag BOD)/
(mg MLVSS)(day) and effluent BOD as low as 5 mg/1 were achieved.
     A kinetic description indicated  a yield coefficient of 0.92  (mg MLVSS produced)/
(mg BOD removed), a decay constant of 0.027 day"  and a half-saturation constant of
16 (mg BOD)/I.  The significance of these kinetic characteristics in process  design
ind operational control is presented.
     Four solids separation sys terns "Vibratory screens, enhanced  gravity separation
lissolved air flotation and hydro-centrifugal cleaned screens=°were tested for ac£l~
 ated sludge solids separation.  Vibratory screens were not effective for separation
>f high-rate activated sludge solids  under the operating conditions employed  during
:his study.  Enhanced gravity separatorsa howevars were effective for separation of
                                     only at very low operating overflow rates0
17.
                             KEY WORDS AND DOCUMENT ANALYSIS
                DESCRIPTORS
                     b.lDENTIFIERS/OPEN ENDED TERMS
             c. COSATI Field/Group
  Sludge, *Sewage,  *Activated  sludge
  process,  *Sewage  treatment,  Waste
  water, Sewage  filtration, Separa-
  tion,  Biochemical oxygen demand,
  Reaction  kinetics,  Sewage disposal
                       High-rate  activated
                       sludge system, Chino
                      (California),  Solids
                       separation,  Biologi-
                       cal  kinetics
                13B
18. DISTRIBUTION STATEMENT

  Release  to Public
                      19. SECURITY CLASS (This Report)
                        UNCLASSIFIED
                                           20. SECURITY CLASS (Thispage)

                                             UNCT.ASS IFTF.n
EPA Form 2220-1 (0-73)

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        DEMONSTRATION OF A HIGH-RATE

          ACTIVATED  SLUDGE SYSTEM
                       By

                Ching H.  Huang
            Donald  L. Feuerstein
          Engineering-Science,  Inc.
         Berkeley,  California  94710

                      and

                Elmer y,.  Miller
                 City of Chinb
             Chino,  California  91710
            Gr.mt No. WT'RD  16-01-67
         Pr.< •, ram Element No.  1BB043
                Project Officer

                 Gerald Stern
Advanced  Waste Treatment  Research Laboratory
   National  Environmental Research Center
           Cincinnati, Ohio  45268

                Bopraduced by
                NATIONAL TECHNICAL
                INFORMATION SERVICE
                   US Department of Commorco
                    Springhold. VA. 22151

   NATIONAL  ENVIRONMENTAL RESEARCH CENTER
      OFFICE  OF RESEARCH  AND  DEVELOPMENT
    U.S.  ENVIRONMENTAL PROTECTION AGENCY
            CINCINNATI, OHIO   45268

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       •  '      •             .REVIEW NOTICE '

     The National Environmental Research Center--'
viewed this report and approved its publication.  Approval does not
signify that the contents necessarily reflect the views and policies
of the Uo S, Environmental Protection AgencyB nor does mention of
trade names or commercial products constitute endorsement or recom-
mendation for use.                             .         .
                                  ii

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                              FOREWORD

     Man and his environment must be protected from the adverse effects
of pesticides, radiation, noise and other forms of pollution, and the
unwise management of solid waste.  Efforts to protect the environment
require a focus that recognizes the interplay between the components of
our physical environment—air, water and land.   The National Environ-
mental Research Centers provide this multidisciplinary focus through
programs engaged in

     o studies on the effect of environmental contaminants on man and
       the biosphere, and
     o a search for ways to prevent contamination and to recycle
       valuable resources.
     As part of these activities„•  the study described herein presents
an investigation to determine the  feasibility of using a high-rate
biological system for treating municipal wastewater at lower costs
while still maintaining effluent quality standards, with possible reuse
of the treated wastewater  for recreational purposes.
                                   A. W.  Breidenbach, Ph.D,
                                   Director
                                   National  Environmental
                                   Research  Center, Cincinnati
                                   iii

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                                ABSTRACT

     An optimum performance activated sludge  systems  comprised  of  an
accelerated high-rate activated sludge process  and  associated solids
separation processes, was designedB  constructed and operated  at th@ City
of Chino as a biological treatment system  utilizing the  maximum growth-
rate potential of activated sludge as a means of removing organict and
possibly inorganic nutrient»  materials  from domestic  wastewater,,
     Operating results  from this  investigation  indicate  that  full°scal®
systems can be operated at high growth rates  and high subsfcrefe©
rates with concomitant  high substrate removal velocities and  high
effluent.  Substrate loading  rates ae high as 3.6 (rag BOB)/(sag  MLVSS)
(day) and effluent BOD  of as  low  ss  5 rag/i wer© achieved0
     A kinetic description of this activated  sludg© system isi«Sica£@d  &
yield coefficient of 0092  (sag MLVSS  produced)/(tug 309 reaowsd),, a decay
constant of 0 = 027 day   based on  BOD0 a maximum substrata ir'ssaow
ity of 4»1 (mg BOD iremoved)/(mg HLVSS) (day),  a maximum specific
               = 1
rate of 3»8 day   „ and  a half-saturation  constant of  26
significance of  these kinetic ch©recte sis tics ia process)
ational control  is presentedo
     Four solids  separation system®0 viz08 vibratory  screeasso enhancod
gravity separation^ dissolved air flotation and hydro°c®n£iri£iiigsl cl®SB©d
screens, were tested  for activated sludge  solids separation   Vibratory
screens were not  effective  for the separation of high-rat© &ctivat
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     If advantage is to be taken of the substrate removal capabilities of
high-rate activated sludge systems, a greater effort in the development
of improved mechanical solids separators is indicated.
     This report was submitted in fulfillment of Project Number 17050 DZE
Grant No. WPRD-16-01-67, by the City of Chino, California, under the par-
tial sponsorship of the U.S. Environmental Protection Agency.  Work wa^
completed as of August 1974.

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                             CONTENTS
Foreward               .        '       . - -                        •
Abstract   .           •          '    '  '•.                 . ' .         Iv
List of Figures  -.  '  .'     ".     '        '   •         . ::  ' •   •   •   vii
List of Tables                                                     ** • •
Acknowledgments                                        ':   ':       S^
Sections                                                .
I      Conclusions                                             .   1
II     Recommendations                                     ;       5
III    Introduction                                        :      .6
IV     Activated Sludge Process description                       8
¥      Theory and Rationale                                       12
VI     Experimental Procedure and Analytical Method               29
VII    Results and Discussion                                     42
¥111   Design. and Operational. Implications.        .. '   . .   .-,'•    ;  126
IX     Glossary  -     •         '•          .  . '     '•   .-  '; '• .  -    133
X      References           '  •   •    '                  •'•'''••       134
XI     Appendix            •                            ,'••"•  138

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                                FIGURES

No.                                                         Page

1        Completely mixed activated sludge process            14

2        Michael is-Menten (Monod) kinetic model               17

3        Water reclamation facilities of City of Chino        30

4        Plot of cell continuity equation using BOD as
            substrate parameter                             ,  62

5        Plot of cell continuity using COD as substrate
            parameter                                         63

6        Cell continuity equation for mean steady-state
           values using BOD as substrate parameter            65

7        Cell continuity equation for mean steady-state
           values using COD as substrate parameter            66

8        Plot of cell continuity equation using BOD and ATP   67

9        Plot of cell continuity equation' using COD and ATP   68

10       Plot of cell continuity equation using BOD and
           dehydrogenase activity                             69

11       Plot of cell continuity equation using COD and
           dehydrogenase activity                             70

12       Plot of Michaelis-Menten  (Monod) equation for
           accelerated high-rate activatod sludge system
           using BOD as substrate parameter                .  73

13       Plot of Michaelis-Menten  (Monod) equation using
           BOD  and ATP                                        74

14       Plot of Michaelis-Menten  (Monod) equation using
           BOD  and dehydrogenase activity                     76

15       Plot of modified Michaelis-Menten (Monod) equation
            for  accelerated high-rate  activated  sludge  system
           using COD as  substrate  parameter                   77

16       Plot of modified Michaelis-Menten (Monod) equation
           using COD and ATP                                  78

 17      Plot of modified Michaelis-Menten (Monod) equation
           using COD and dehydrogenase activity              79

                                  vii

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                          FIGURES (Continued)
18       Relationship between oxygen transfer rate and
           BOD removal velocity                               95

19       Estimated oxygen transfer rate and COD removal
           velocity                                           96

20       Effect of organic loading velocity on sludge
           volume index                                  .     112

21       Hydraulic capacity of vibratory 0.044~rasi
           opening (325-aaesh) screen                          117

22       Hydraulic capacity of vibratory 0.037-=mm
           opening (400-mesh) screen                          118

23       Hydraulic capacity of vibratory 0.014- by 0.105~mm
           opening (720= by 140-mesh) screen                   1.19

24      ' Effect of surface loading on  gravity settler
           performance                                        122

25       Effect of cell  age on gravity settler performance    123
                                  viii

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                                TABLES

No.                                                               Page

1     Process Monitoring Characteristics and Daily Routine
      Laboratory Analyses                                         37

2     Primary Effluent Wastewater Characterization                43

3     Summary of Primary Effluent Wastewater Characterization     47

4     Mean Values of Steady-State Performance Parameters          49

5     Summary of Steady-State Measurements                        51

6     Summary of Steady-State Performance Parameters              54

7     Steady-State Active Organism Concentration Measurements     58

8     Steady-State Performance Characteristics Based on
      ATP and Dehydrogenase Activity                              60

9     Evaluation of Cell Continuity Equation Using ATP and
      Dehydrogenase Activity as Active  Biomass Parameters         81

10    Evaluation of Michaelis-Menten  (Monod) Equation Using
      ATP and Dehydrogenase Activity  As Active Biomass Parameters 82

11    Summary of Most  Probable Kinetic  Growth Constants  of
      Accelerated  High-Rate Activated Sludge System               83

12    Activated Sludge Process Kinetic  Constants                  84

13   Oxygen Transfer  Kinetic Constants in  Aerobic  Biological
      Processes             .                                     89

 14   Oxygen Transfer  Kinetic Data and  Sludge Volume  Index        91

 15    Steady-State Nitrogen  and  Phosphorus  ConccnLr.nl ions        98

 16    Average  Nitrogen and Phosphorus Concentrations  in
       Primary  and  Secondary  Effluents                             102

 17    Nutrient  Removal Velocities and Removal  Efficiencies         104
                                   ix

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                         TABLES (continued)

No.                 '                                             Pag®

18      Vibratory Screen Performance Data                         114

19      Summary of Vibratory Screen Performance                   116

20      Gravity Settler Performance                               121

21      Design and Operational Parameters  for Activated           129
        Sludge Processes

22      Design Coaaparison Between Conventional and High-Rate      131
        Chino Activated Sludge Processes

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                            ACKNOWLEDGMENTS

     The following key individuals from the City of Chino were responsible
for implementation and conduct of the project:  Mr. John R.  Wright,  City
Administrator; Mr. Elmer Miller, City Engineer; Mr. James Diaz, Finance
Officer; Mr. Arthur Hern, Manager of City Services; Mr, James Estrada,
Chief Operator; and Mr. Tibaldo Canez0 Chief Chemist.
     The assistance of Mr. Gerald Stern, EPA Project Officer, is grate-
fully acknowledged.
                                                                     *
     Participants from Engineering-Science, Inc. in the project were
Mr. Kline P0 Barney, who served as Project Manager during the initial
and data acquisition phases of the study.  Dr. Donald L. Feuerstein
replaced Mr. Barney as Project Manager during the data evaluation and
report preparation phases of the project.  Mr. Arthur S. Anderson served
as Project Engineer and was responsible for the performance of the project
during the development and acquisition of all field and laboratory results.
Dr. Ching H. Huang evaluated the data and results and prepared the final
report.
     Dr. Erman A. Pearson acted as special consultant on the project.
                                   xi

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                               SECTION I
                              CONCLUSIONS

     This investigation has yielded quantitative kinetic descriptions of a
full-scale activated sludge plant, which include growth rates, decay rate
constants, yield coefficients and other kinetic coefficients and constants.
Results from this investigation indicate that plant-scale systems can be
operated at high growth rates and high substrate loading rates with concom-
itant high substrate removal velocities and high quality effluent.  Sub-
strate loading rates as great as 3.6  (mg BOD)/(mg MLVSS)(day), substrate re-
moval velocities as large as 3.2 (mg  soluble BOD removed)/(mg MLVSS)(day)
and effluent soluble BOD concentrations as low as 5 mg/1 were observed dur-
ing this study.  Based on this investigation, a number of specific findings
and conclusions are presented.
KINETIC CHARACTERIZATION OF ACCELERATED HIGH-RATE ACTIVATED SLUDGE SYSTEMS
     The activated sludge process was operated as a very low-rate system0
viz,, average growth rate of 0.035 day" ,  or as a very high-rate system,
viz, average growth rate of 2.16 day  .  Optimum BOD loadings on an
activated sludge system with gravity cell separation appear to be in the
range of 2.0 to 3.6 (mg BOD)/(mg MLVSS)(day).
     The cell continuity equation, 1/6  = Yq - kds and the Michaelis-
Menten (Monod) equation, v = uS,/(K  + S,)„ were used to describe kinetic
                               AS    1
characteristics of the accelerated high-rate activated sludge system, and
system kinetic coefficients and constants were developed.
     Kinetic analysis of data from the full range of substrate loading
 rates  employed  Ln  this study, vdz, 0.137  to 3.64  (mg BOD)/(mg MLVSS)(day),
 suggests  the  following kinetic coefficients and constants for the acceler-
 ated high-rate activated sludge system:

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                                       Substrate Paremetes
Kinetic Constants
Yield coefficient, ¥

Decay constant„ k^

Maximum substrate   A
  removal velocity„ q
Maximum specific^
  growth rateB  y

Half-saturation
  constant, K
Nonbiodegradable
  substrate ccmcen-
BOD
0 09 (mg MLVSS)
°°92 (mg BOD)
Oo027 day"1
0-a-s J
~00023 <
COD
CEJB MLVSS)
(sag CC3}
Jay°
 4.1
        (mg BOD)
     (mg MLVSS)(day)
3o8 day°
26 mg/1
   tration,  K
             COD
8,4
                         2o7
                       95 mg/1
                        20 mg/1
                                .pas COD)
     The usefulness  of  kinetically describing accelerated high=rate
activated  sludge  systems  using ATP and dehydrogenase activity as active
biomass parameters was  not  documented due  to the high variance of the
limited data obtained.
     The relatively  low values of the half-saturation constants0 K „„.
                                                                  SBUaJ
= 26 mg/1  and KSCOD  a 95  mg/1, indicate that both BOD and COD are adequate
substrate  parameters; and the  organic substrate concentration expressed
as either  BOD or  COD was  the rate-limiting factor in the accelerated
high-rate  activated  sludge  system.,
     Least-square analysis  suggests  the  following values of  constants in
the oxygen requirements equation, U  = aqX| + bkjXjj, assuming that the
oxygen  transfer capacity  for the EIMCO-SIMCAR aerator was  1022 (kg 02
transferred)/(kw-hr consumed)  [2.0  lb/(hp-hr)] :

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                                        Substrate Parameter
Aeration Constants                   BOU                  COD
                                 (mg CO            '     (rag 0.)
                           0.438 -7 -    -          0.174
                                 (mg BOD)                (mg COD)
                                     (mg 0,)                 (rag Oj
       bk,                 0.432 -;	»„„„„:>.—r   0.414
         d                 ""•"• (rag MLVSS)(day)   v*-   (rag MLVSS) (Jay)

NUTRIENT REQUIREMENTS AND REMOVAL
     A minor degree of nitrification took place in the accelerated high-
rate activated sludge system as the nitrite plus nitrate increased on the
average from 0.08 mg/1 as N in the influent to 0.90 mg/1 as N in the
effluent.
     The net yield coefficientsc Y „ with respect to  specific nutrients,
obtained from data representing a wide range of substrate loading rates,
viz, 0.137 to 3.64 (mg BOD)/(mg MLVSS)(day)s  were found to be 11.3 (mg
MLVSS produced)/(mg Kjeldahl nitrogen removed), 20.1  (mg MLVSS produced)/
(mg ammonia removed), 14.4 (mg MLVSS orr. 'Mced)/(mg total dissolved phos-
phate as P removed) and 28.5 (mg MLVSS produced)/(mg dissolved orthophos-
phate as P removed).
     Based on cell yield coefficient and the quantities of nitrogen and
phosphorus requirements of the activated sludge determined in this study,
the nutrient requirements were estimated to be  112  (mg N)/(g BOD removed)
and 33  (mg P)/(g BOD removed) as compared to the most commonly  reported
values  of 40 (mg N)/(g BOD removed) and  6 (mg P)/(g BOD removed).
                                       .,<#jCr
     The Michaelis-Menten (Monod) model  for nitrogen  and phosphorus
removals could not be used because of  the high  concentrations of these
constituents in the primary effluent and the very small removals that
were effected  in the activated sludge  process.

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SOLIDS SEPARATION SYSTEMS
     Only about 10 percent of the applied hydraulic loading „ which ranged
                   *   3   2                           7
between 804 and 24o4 m /(m )(day)[200 and 600 gal/ (f t ) (day) ] , passed
through the vibratory screen with a 0..014- by O.lOS-ssn opening (720~foy
                                                         2                2
140-raesh) at solids loadJug rates of less than 97,9 kg/(ta )(day)[20 lb/(ft )
      .  These filtration  rates are  too  low  in comparison to gravity settlers,
     The three vibrating screens with 00044=mm opening  (325=mesh)p 0.037-nan
opening (400-mesh) and 00014- by 00105=uBn opening  (720- by  140-mesh) re-=
moved 38, 49 and 91 percent  of mixed liquor  suspended solids, on  the aver-
age, respectively o  Solids removal was low in all  but the smallest size
screen, but even the highest solids  removal  does not compare with the  95
to 99 percent solids removal achieved with a gravity settler operating at
an overflow rate of about  1202 m3/(m )(day) [300 gal/(ft )(day)]0
     No solids separation  data were  obtained on the gravity settlers at
                                                                    3   2
conventional secondary clarifier overflow ratesB io©o0  about 3206 m /(m )
                 o
(day) [800 gal/ (ft ) (day) 3 9 but gravity settlers were effective  in separating
high-rate activated sludge mixed liquor  suspended  solids at overflow rates
of about 12 „ 2 m3/(m2) (day) [300 gal/ (ft2) (day)] .

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                               SECTION II
                            RECCHWENDATIONS

     Based on the results and conclusions reported herein, the following
recommendations are offered:
     Kinetic descriptions of the biological process should be developed
for all activated sludge plants to provide a rational and accurate basis
for process design and operational control to achieve a specified efflu-
ent quality.  To permit development of kinetic data, all activated sludge
plants should have flow meters located on the aerator influent9 return
sludge and waste sludge lines and continuous proportional samplers located
on the raw sewage, primary effluent (aerator influent)„ aerator effluent
and return sludge and final plant effluent lines.
     A better measure of the active solids content of the activated sludge
for description of activated sludge growth kinetics than the mixed liquor
volatile suspended solids (MLVSS)9 adenosine triphosphate (ATP) or dehy-
drogenase activity needs to be developed.
     If advantage is to be taken of the substrate (pollutant) removal
capabilities of high-rate activated sludge systems, increased effort
should be devoted to the development of more efficient secondary cell
separators.
     Because only about one year was funded under this demonstration grant
for operation of the demonstration processs more time and effort is needed
to investigate process kinetics ands particularly;, potentially better
solids separation systems.  Time and funds permitted only a small part
of the scope of work plan to be completed.

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                              SECTION III
                              INTRODUCTION

     Biological Haste 'treatment systems are currently the most widely used
method of removing organic materials from municipal and industrial waste-
waters„  The most versatile  and efficient of the available biological
processes is the activated.sludge system in which flocculated biological
growths are continuously circulated and contac£©d with primary effluent
in an aerated environment and then separated from the treated tjoEtswatez
by sedimentation,,
     Utilization of  the maximum growth-rate potential of  the activated
sludge process is proposed for removing organic materials from waetewater,,
at potentially loner costs if the active biological cells,, or solidsD can
be separated effectively from the effluent  liquid,,  A maximum growth=rate
system could result  in relatively small  treatment plants  which  caa be
constructed at significantly lower  costs.
     Based on  this  approach„ the City  of  Chino was  provided  a grant  by
the UoSo Environmental Protection Agency  to  demonstrate  the  feasibility
of an optimum  performance activated sludge system,,  comprised of en  acc
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OBJECTIVES
     The general objective of the study was the development of an optimum
performance high-rate activated sludge system and the kinetic characteris-
tics of the proposed process.  Specific objectives were:
     (1)  To describe the process by kinetic analysis which would provide
     a more rational basis for design and operation of the activated sludge
     process;
     (2)  To determine the process kinetic characteristics, e.g., maximum
     growth rate, decay rate constant, yield coefficient and half-saturation
     constant, with respect to system performance parameters;
     (3)  To delineate the nutrient, i.e., nitrogen and phosphorus, removal
     as a function of the process operating parameters;
     (4)  To evaluate the performance of alternative mixed liquor solids
     separation  systems, such as enhanced gravity sedimentation, vibratory
     screens,  dissolved air flotation and pressurized hydro-centrifugal
     screening;  and
     (5)  To determine the suitability of using  the plant effluent  from a
     high-rate activated sludge process  for recreational purposes,
CONDUCT
     This project was conducted in  compliance with  the  requirements of the
agreement between the City of Chino  and  the U.S. Environmental Protection
Agency  under the Grant No. WPRD 16-01-67.
     The  design  and  construction of  the  demonstration activated  sludge
plant was completed  in  1970.  The demonstration  plant was operated  for
 15 months,  extending from October  1970  to January  19-2.
     Throughout  the  grant period, Engineering-Science,  Inc0 served  in the
role of design engineers and  provided  the project  engineers for  plant
operation and  documentation.

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                               SECTION IV
                  ACTIVATE) SLUDGE PROCESS DESCRIPTION

    • The activated sludge process can be defined as a system in which Che
flocculated biological growths are continuously circulated and contacted
with organic wastewater in the presence of oxygen.  The system involves
an aeration step followed by  a solid-liquid separation step, from which
most of the separated sludge  is recycled back for mixture with the waste-
water and the remainder is wasted (waste activated sludge)„  Biological
synthesisf respiration, oxidation, flocculation and solids separation
are the five subprocesses which constitute the activated sludge process0
The activated sludge process  is very flexible and can be adapted to
almost any type of biological waste treatment problems  Many modifications
of activated sludge process have been developed.  The various modifica-
tions in use today are conventional, complete-mixed, step-aeration, modi-
fied aeration, contact-stabilization, extended aeration, Kraus process,
high-rate aeration and pure-oxygen systems,

OPTIMUM PERFORMANCE ACTIVATED SLUDGE PROCESS
     The optimum performance  activated sludge process consists of an ac-
celerated high-rate activated sludge unit and associated solids separation
unitso  The concept of this proposed process recognizes that there are two
forms of substrate in wastewater—soluble substances and colloidal-suspended
material.  Colloidal-suspended material can be removed effectively by solids
separation systems dhich  utilize  flocculation as  a precursor to separation.
The soluble fractioa  can  be removed by biosorption, biosynthesis and bio-
logical oxidation  in  aeration tanks.

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     Recognizing that uptake of soluble substrate by bacterial cultures
can be very rapid, it is realized that extremely high-rate activated
sludge processes could be constructed if a solids separation system cap-
able of removing the bacteria and colloidal-suspended matter could be
developed.                                                  x
     Current activated sludge, systems rely on flocculent bacterial cul-
tures for removal of both soluble and insoluble forms of substrate.  The
optimum performance activated sludge process relies on the active bac-
terial culture for rapid uptake of soluble substrate and the adsorption
of colloidal matter on the active biological mass with an improved solids
separation system.  The potential advantage of this system includes the
application of higher organic loadings, which results in plant size re-
ductions and concomitant reductions in construction costs„

SOLIDS SEPARATION PROCESSES
     Separation of the biological cells  (solids) from the treated waste-
water is the objective of the second phase of the activated  sludge pro-
cess o  In traditional forms of the activated sludge process„ the biologi-
cal  reactor is operated in a manner which produces a sludge  which is
readily settleable in a separator„  The  close coupling of the biological
reactor and the separator makes the performance of these units inter-
dependent.
     All solids separation devices can be classified into two distinct
types5 gravimetric separators and solids restraining devices.  The
gravimetric separation  devices include the separators in which solids
are  transported through  the liquid either by gravity} centrifugal force
or static electrical  force,,  The  solids  restraining separators include
all  devices in which  solids are  retained on media upon passage of the
liquid.  The media can  be of a fixed nature such as screens9 fabrics,
papers  and membranes  or of  a nonfixed  configuration like granular media.
      Gravity sedimentation  is  the principle method of solids separation
 used in  the activated sludge process because to  date  it has  the  best
 cost/effectiveness ratio.   Therefore,  the production  of settleable  sludge

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is one of the primary requirements for the activated sludge process,
Howevers, gravity sedimentation for the final step in the ac£ivat©
process has several fundamental disadvantages which ares
     (1)  The iaAiiity  to separate sludges effectively having specific
     gravities aea? that of the liquid;
     (2)  The inability  to concentrate filamentous sludgesD which have
     poor settling characteristics;
     (3)  The practical  inability to remove by gravity sedimentation
     particles as small  as the size of cellular particles that on©
     would like to remove; and
     (4)  The instability of  the activated sludge process caused by
     uncontrollable variations in particulate solids (cells plus detritus)
     characteristics and the  inherent variations in the hydraulic charec~
     teristics of sedimentation basins.
     All of these process limitations can be tolerated if it is not nec=
essary to produce a consistently high quality effluent.  However8 in-
creasing performance standards are forcing designers to re-examine the
process as a whole and  to focus on the process rate-limiting sgep of
final solid-liquid separation (sedimentation)„
     Much work has been done  to improve  operation of biological reactors
to minimize solids separation problems associated with variable sludge
characteristics„  Organic and inorganic  sludge conditioners havs been
used to increase the size of  particles thus improving solids flocculation
and to increase floe strength, and thereby making them less susceptible
to disaggregation due to hydraulic transient shear.  Some workers have
focused attention on the problem of hydraulic short circuiting and its
effect on solid-liquid  separation.  This work has led to the development
of a number of stilling devices which include tube settlers9 lamella
settlers and tray; settlers.   Moreover, some designers have  added a filtra-
tion process downstream of  the biological process to meet more stringei.t
                 /
water quality  requirements.
                                   10

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     Development of improved solid separation systems  which  are  better
suited to the variable characteristics requirements of biological  pro-
cesses is needed if maximum use is to be made of biological  removal
mechanisms.
                                   11

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                              SECTION V
                          THEORY AND RATIONALE

     Significant progress has been made in the practical application of
biological systems to municipal and industrial wastewater treatment,
However9 most of the progress in waste treatment technology has been the
result of field experimentation,, largely on a trial and error basis.
Much of the research in waste treatment has been devoted to the develop-
ment of rational or semi~rational explanations of the phenomena observed
in practice,  ?
     The objective of biological waste treatment,, namely the removal of
organic materials from the was£ewaters usually expressed in terms of
biochemical oxygen demand (BOD) or chemical oxygen demand (COO), is the
major consideration of kinetic analysis.  Moreoverp the activated sludge
process can be used to remove from the waste&ater stream some of the
essential nutrientsD such as nitrogen and phosphorusD by incorporation in
cell tissue.  The proper kinetic descriptions of substrate and nutrient
removals should provide a rational basis for the analysis and design of
activated sludge systems,
PRINCIPAL REACTOR TYPES AND FLOW CHARACTERISTICS
     Most biological treatment processes utilized in wastewater treat-
ment are designed to take place in continuous-flow systems.  Since  such
processes are time dependentsD the hydraulic residence time and  the
mixing characteristics of the systems are of vital importance.  The
actual mixing characteristics vary with  the design of the system and
are too complex to be described precisely.  For  this reesoa0 use is made
of simple flow models in estimating  these characteristics.
                                   12

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     There are three major types of biological system models, classi-
fied in terms of flow condition and mixing characteristics, which are
commonly used in the activated sludge process.                                  '..
                                                                                t
Plug-Flow Reactor                                                               }
     In a plug-flow reactor, each element of the flowing mass follows
another in sequence as though separated from it.  ConsequentlyB there
is no longitudinal mixing between the elements although there may be            '
lateral or radial mixing within each element.  Each element is in the
system for a time equal to the theoretical retention time.  This type           •:
of flow would be approximated in a long pipe having a relatively small          '
cross section.
Continuous-Flow„ Stirred-Tank Reactor
     A continuous-flow, stirred-tank reactor is a simple homogeneous
system consisting of a stirred tank into which influent wastewater is fed
and intermixed immediately with contents of.the reactor.  The liquid in         \
the reactor is completely mixed so that its properties are uniform and
identical with those of the effluent.  Thus, at a steady-state condition,       ]
                                                                                I
the substrate level and physiological conditions of the cells in the            •
reactor are maintained throughout the reactor at a constant level.              t;

Arbitrary-Flow Reactor
                                                                                t
     Arbitrary-flow represents any degree of partial mixing between plug
and completely-mixed flow.  This type of flow is encountered frequently         •;
in actual aeration tanks and is difficult to describe mathematically.
Thereforeo in the kinetic analysis of arbitrary-flow reactors„ plug-flow
or completely-mixed flow models are usually assumed.
                                                                                l
KINETICS OF COMPLETELY-MIXED ACTIVATED SLUDGE PROCESS                           ;•
                                                                                l
     The completely-mixed process, schematically depicted  in Figure  10 is       j
characterized by a series of systems of constant volume, being as a whole       '
in a dynamic steady-state condition with essentially constant  concentra-        •„
tions of organic substrates and of activated sludge in the system.              '
                                    13

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SLUD6E
WfiSTE
                          Fr,
F =
Fr =
F =
X,=
X2 =
Kr =
SQ =
                     Influent flow rate
                     Return activated sludge  flow  rate
                     I§ste activated sludge flai  rat@
                         .
                     Influent cell concentration
                     Mixed liquor cell concentration
                     Effluent cell concentration
                     ietcurn activated sludge cell  con cunt ration
                     ln?iu@nt substrata concentration
                   = Effluent substrate concentration
                           of aeration tank
                                            @ll
               1   e@mpl§tisly  minsd' activated
                                 14

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Continuous-flow, completely-mixed system cultivation permits determina-
tion of process kinetics and parameters which can be used both in theo-
retical analysis and in practical system design „
Basic Assumptions
    To develop rationally a mathematical model for a continuous-flow,
completely-mixed system, two basic assumptions are made:
    (1)  The specific growth rate of organisms in the reactor is some
    function of the rate-limiting substrate concentration, thus

                            u «•£  ft-f(s>                      (i)

    where     X = concentration of activated sludge
              Vi = specific growth rate
              S = concentration of organic substrate,
    (2)  The specific growth rate of the organisms varies with the rate
    of consumption of the limiting organic subs t rate 0 namely
    where      Y  == yield  coefficient,,

    It  is  generally assumed  that  the  yield coefficient B  Y0  is  a  process
    kinetic constant,
 Monod Model (Michaelis-Menten Equation)
    The most widely accepted model for expressing tht- relationship between
 specific growth  rate and substrate concentration is  the  rectangular hyper-
 bola.  This relationship has a theoretical basis in  the  Michaelis-Menten
 equation which was  developed to describe the rate of an  enzyme reaction
 as a  function of substrate concentration 'i\eierence  1) „  as  well  as an
 empirical basis  as  proposed by Monod  (References 2 and  3)  to describe the
 relationship between bacterial growth rate and substrate concentration.
                                    15

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It takes the
             specific growth rate
K  ° h©l£~saturatloa constant D numerically equal £o the
     substrate concentration at uhich the specific
     rate is one-half the maximum growth ra£eB i«,ee^ p
                                                                      M/2<
    The Michaeiis-Menten  (Mcmod) kinetic model for describing eh© rela~
tionship between the growth rate and substrate con cent rat ion „ ahdvri in
Figure 20 has been -widely used by microbiologists and engineers working
with continuous culture systems (References 4, 5, 6P 7  and  8).
                                                  system
                                                     state
Kinetics of Activated Sludge Process
    In developing  the process kinetics  of  the activated
with cell recycle 8  continuity of biomass and substrates in
condition are maintained.

Materials Balance  for Cell Biomass —
    One of the  important  characteristics of the  activated sludge system
is cellular recycle and the controlled  wasting rates of sludge produced
during treatment »   This permits control of the cell concentration and
effluent quality  over considerable  limits. For  a  continuous=flow0
stir red-tank  reactor with cell  recycle „ a  materials balance  for the
entire process  is  expressed by  the  following equation;
 rate  of  change of
 cell  biosjaso  in
 the reactor

CD

rate of
input of
cells

-

rate of
output of
cells

-!-

growth
rate of
cells

=.

decay
rate of
cells
or
 where
              .  dX
                      FX0 - (F - Fw)X2 - FwXr
     decay  rate.
                                                     (4)
                                    16

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C9
                                   s,
                    SUBSTRATE CONCENTRATION
    Figure  2   Michael is-l^enten (^onod)  kinetic
                               17

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    At steady state0 dX./dt ° 0D and
          dX
                    wv  ... wv
                    FXQ - FX2
                        - V
                                                   kd)VXl
                                                    (5)
 or
 1
 I.-J
 8.
                              X1V
                                               U = k.
                                                    (6)
where
F(X_ - Xn) 4- F (X  - X0) » net growth of ceils
   &    \j     W  ST    A
                                    X.V » mass  of  cells  in activated
                                         sludge system

                                     6  = mean  cell  age.
                                     c               °

    In the absence  of  a practical method for estimating the biological

activities of  incoming cells„ which are relatively  insignificant  com~
pared to those in the  reactor,  the amount  of active cells in  the  influent
wastewater is  assumed  in the analysis to be  negligible„

    SimilarlyB a materials balance for cells around the reactor (see
Figure 1) can  be written as follows;
  rate  of  change of
  cell  biomass  in
  the reactor
=
rate of
input of
cells
-
rate of
output of
cells
*
growth
rate of
cells
„
decay
rate of
cells
or
         dX.
(FX
                  ()
                    -  (F
                                                                      (7)
    Assuming that  the process is at steady state „  i0e0,  dX./dt  ° 00  the
following  expression is obtained!
                               18

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    dX
       - - 0
or
_!_
6
              F(XQ -
            F -
                                                                     (13)
At steady state,
                          0, and

                                    19

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                            s0-j1)v    (SQ - SI)Y
                      xi°—vJT—Q	JTe	
where                t> ° hydraulic  residence time,, V/F.
    It should be  noted  that  the specific  growth  rate  is  a  function of
the substrate removal velocity„ q8  which  is  a  rational measure  of the
cellular  removal  activity„  that iss the mass of  substrate  (BOO,, COD8 etc0)
removed from the  Haste  stream per unit mass  of "active organism" per unit
of time (g  substrate removed)/(g cells) (day) „.'  Thus,,
                               Y   ¥(SQ "
            s — - —   - - ° - -
                                     - x )
                                        2       "    A . - k  •        (16)
     Solution of Equations 16 and 17 for the raactor substrate coacantra-
 tion0  mean cell age0 hydraulic residence tims and cell concentration pro-
 vides  the following expressions;
                             YSQ - (1/9C
                        S
                         l =           Y     ^                        (19)
                                 Y(S  - S.)
                                                                     (20)
                                    20

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and                       0 -      0    l                          (2D
                            -  xi(i/ec  + kd)

    The foregoing equations are of major significance indicating the
interrelationships involved between the steady-state physical and bio-
logical parameters of the activated sludge system.

Process Efficiency
    Process efficiency can be expressed as follows:

                                so - si
                            E - -2=	                            (22)
                                  S0
    Solution for (SQ - S.) from Equations 3 and 15, and division of
(S0 - S.) by SQ, produces the following  expression  for efficiency;
                                 P9X.S
                                      7-c ^                        (23)
    Thus the efficiency of an activated sludge process for a given in-
fluent substrate concentration is a function of hydraulic residence
time, 0; cell concentration, X^ yield coefficient, Y; maximum growth
rate, M; and half-saturation constant, K „  It should be emphasized that
                                        S
once a given effluent concentration is specified, E is determined by the
feed substrate concent rat ion s SQS> and the hydraulic residence time, 0,
The parameters y, K  and Y are kinetic constants and are determined by
                   S
the microbiological characteristics of the system.  Only the cell con-
centrations, X.0 and the hydraulic residence time, 0P are variable in the
system; however„ only one of the two can be independently varied with
time,,  Either X. or 6 can be selected, but once a single parameter is
fixedj, the other automatically becomes fixed»  From this,, it can be con-
cluded that either the efficiency, E, or the effluent concentration, S.s
should be correlated with the product of the reactor cell concentration,
X., and hydraulic residence time, 0, (viz,, E or X. vs. X.9)„
                                 21

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Substrate and Nutrient Uptake and Removal
    The biological  species  composition of activated sludge will vary
widely and will  depend on many  factors,,  the most important of which er©
the nature of the organic substrate  and  the growth rate of the syste®0
Thus  it may  be expected  that  the elemental composition of activated
sludge will  also vary widely,,
    Substrate and nutrient  removals  from wastewaters by activated sludge
can be considered to be  initially a  high removal of suspendedD colloidal
and simple soluble  substrate  and nutrients followed by a slot? progressive
removal of complex  soluble  substrate and nutrients.   Initial  substrate
and nutrient removal is  accomplished by  the following uptake mfechsaismss
(1) entneshtnent of suspended matter in the biological floes, (2)  physico-
chemical adsorption and absorption of colloidal matter on the biological
floes and (3) biosorption of soluble  organic matter by the organisms.
The colloidal and suspended materials must undergo breakdown to smaller
molecules before they can become available for cellular synthesis.
     Several mathematical models have been suggested to explain the
mechanism of substrate and nutrient uptake by biological oxidation pro-
 cesses (References 9 and 10)0  These models have shown that at high sub-
 atrate (or nutrient) levels the rate of 'substrate (or nutrient) uptake
 per unit of cells will remain  constant  (zero-order) to a limiting
 strate (or nutrient) concentration below which the uptake rate will
 become concentration-dependent (first=order) and decrease0
     At low substrate  (or nutrient) concentration,, the removal rate
 a linear relationship with substrate  (or nutrient) concentrations
 overall relationship  between removal  rate and concentration is
 to follow the Michaslis-Menten  (Monod model) equation (see Figure 2) „
                                   q s,
                                    22

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where     q « substrate (or nutrient) removal rate
          q s maximum substrate (or nutrient) removal rate
          Y " yield coefficient with respect to specific substrate (or
              nutrient).
    The yield coefficient with respect to specific substrate or nutrient
(nitrogen or phosphorus) generally is considered to be constant.  By re-
arrangement of Equation 15, the yield coefficient can be related to sub-
strate or nutrient uptake, (SQ - S.); specific growth rate,, y; hydraulic
residence time, 6; and steady-state cell concentration, X,.  Thus,

                                 MX. 8
                            "                                      (25)
                                so-si
Oxygen Requirements  and Oxygen Transfer
Oxygen Requirements—
    The  activated sludge  process  is  an aerobic  process requiring a  con-
tinuous  supply  of oxygen  for  the  oxidation  of substrate.   In biological
oxidation  a  portion  of the  energy released  from substrate  oxidation is
stored by  the attachment  of a phosphate molecule to  an adenosine diphos-
phate (ADP)  molecule to form  an adenosine triphosphate (ATP) molecule,
The ATP  molecule is  later utilized in the performance of biological
functions  such  as substrate transport across  the cell wall and  cell
membrane against a  concentration  gradient,  and  biosynthesis.
    Substrate entering a  biological system  is only  partially oxidized
as portions  of  the  substrate  are  used in  the  synthesis of  cell  protoplasmc
The degree of substrate oxidation is dependent  on the bond energies and
structure  of the substrate.  Although there are substantial differences
in the degree of oxidation  of a given substrate, an average relationship
for estimating  the  oxygen requirement per unit  mass of substrate can be
developed.
    Cell protoplasm and stored substrjtt,  in addition to  the  influent
substrate, are  continuously being oxidized.  This reduction of  biomass
                                  23

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also requires oxygen and th® total oxygen requirement for a givaa system
is the sum of the oxygen- requirement for decay or endogenous respiration
and the oxygen requirement for substrate metabolism and subsequent bio=
synthesis„
                   t
Oxygen Transfer—
    To estimate th®; quantity of oxygen transferred to the raix©d liquor in
activated sludge systems0 it is convenient to identify th© relationship
between oxygen transfer and aerator power consumption„  The consumption
of oxygen per mass bf substrate utilized and the oxygen requirement for
sludge oxidation are primary considerations in the selection of aerators
for activated sludge facilities and in the estimation of the operating
costs of the activated sludge process.
    Two principal theories—=the penetration theory and the film theory~~
have been advanced to explain the transfer of oxygen (Reference 11) „  The
penetration  theory .conforms to modern molecular kinetic theory uhich re=
lates oxygen transport across a gas-liquid interface to the kinetic energy
of the molecules and Inter-molecular attractive forces.  This approach
appears to offer significant insights into the mechanics of oxygen trans-
fer but has  not been mathematically developed to the point where oxygen
transfer in  aeration basins can be modeled»
    The film theory is based on a physical model in which two fictitious
films—one liquid and one  gas'—exist  at  the  gas-liquid interface.  The
gas molecules  are transported to the outer face of the gas film by mixing
and diffusion  mechanisms.   The gas molecules then diffuse across the stag-
nant gas  film  to  the gas-liquid interface where they dissolve in the liquid
film.  The dissolved gas  then diffuses through this stagnant film to the
boundary between  the film and the bulk liquid phase9 from where it is
transported  throughout  the bulk liquid phase by mixing.  At  the present
 time,  the film theory  is  of greater practical  value than the penetration
 theory,  regardless  of  its questionable  theoretical  basis.

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Process Kinetics with Oxygen Transfer—
    Oxygen requirements can be expressed (Reference 12) as a linear
function of the substrate removal velocity, q, and the endogenous res-
piration rate, k,, as follows:

          UV •=• a(substrate removed) + b(cells oxidized) e (02 used)/day
or
            UV - aF(S_ - S.) + bk.X.V
                     U    1      d 1
or
where
                                V   bkd(so -
U
a
b
                             e
=• rate of oxygen used
™ oxygen requirement per unit substrate removed
=» oxygen requirement per unit cell oxidized.
                                                         (26)
 Thus 5
              U
                             so  -  si
bkd/q)
                                                      (27)
     The  required  oxygen transfer rate  can be written as  a function of
 hydraulic  residence  time,  6;  effluent  substrate concentration,  S,; and
 kinetic  constants for the  system, y, Ys  Kg,  kd,, a and b.  Thus,
             U =
                 Y(SQ-
                                       •f bk
                                                       (28)
     With reasonable estimates of kinetic constants for a given waste
 treatment process, it is possible to "estimate the oxygen transfer rate
 requirements for a wide range of influent 0 effluent and loading charac-
 teristics.

 Active Organism Concentration
     The most important single parameter in the activated sludge growth
 kinetic analysis is an accurate determination of active cell biomass,
 Various methods and parameters have been used to evaluate the active
 organism concentrations.  Most microbiologists have used dry weight of
 suspended matter, volatile suspended solids, optical densitys direct
                                   25

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cell count or viable cell count to evaluate cell concentration,  Lawrence
and McCarty (Reference  13) have used elementary cellular constituents,,
such as carbon;, nitrogen and phosphorus 0 as active organism concentirafciOB
parameters in aaseKobic kinetic analysis 0  Agardy (Reference 14) used
deoxyribonuclsic acid (DM) as an activity parameter in anaerobic digest®rec
Many workers have employed concentration of adenosine triphosphafc® (AT?) or
dehydrogenase activity  to express living cell concentration„
    In the absence of a single accurate active organism concentration
parameter to describe the activity of biological systems„ several par®m°
eters were used in this demonstration study in addition to the traditional
mixed liquor suspended  solids  (MLSS) and mixed liquor volatile suspended
solids (MLVSS)„  The additional parameter of dehydrogenase activity and
adenosine triphosphate  (ATP) were used  to express biomasa concentration
for comparative purposes.'

PROCESS PERFORMANCE PARAMETERS
     The activated sludge process incorporates physical and biological
processes which9 for proper design and  operations, requires a knowledge
of several process variables and their  interrelationships with process
performance parameters.  These independent performance parameters are
organic loading velocity, Lv, and mean  cell age, 0  .
                           V                      C
Organic Loading Velocity
    One of the most important parameters of the activated sludge process
is the organic loading  velocity, or  the food to organism ratio.  The load-
ing velocity„ L^ is equal to the mass  of BOD applied per day per mass of
VSS contained in the aeration tank,  (mg BOD)/(mg VSS)(day)„  The values
of loading velocities vary  from a minimum of 0,05  (mg BOD)/(mg VSS)(day)
for the extended aeration process to about 5 (mg BOD)/(mg VSS)(dsy) for
the high-rate8 supra-activation process (Reference  15),
                                    26

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    Organic loading velocities have also been expressed in terms of mass
of BOD applied per day per unit volume of aeration tank.  Typical values
range from 320 to 6,400 (kg BOD)/(1D000 m3)(day) [20 to 400 (Ib BOD)/
         3
(1,000 ft )(day)J tor extended aeration and supra-activation processes,
respectively.  These volumetric loading velocity parameters neglect the
cell concentration of mixed liquor and the food to organism ratio;
however, they describe the minimum aeration tank volume that should be
adequate for satisfactory treatment.
    One of the principle objectives of this study was to define the ef-
fects of various loading velocities on the dependent variables.  These
dependent variables are effluent substrate concentration,, sludge charac-
teristics and nutrient removal efficiencies.

Mean Cell Age
    Mean cell age, also termed mean cell or biological solids retention
time, 0 , is one of the operational parameters which have been proposed
for the design and operational control of the activated sludge process.
Mean cell age is a measure of the average residence time of the organisms
in the system and can be expressed as follows:
                 VX1                            VX1
  °c - F(X2 - XQ) + Fw(Xr - X2) = F(X1 -XQ) -  (Fr-Fw)
where     F(X2 - XQ) + Fw(Xr - X2> =  loss  of  cells  per day
          VX
            . = cells in the system.

    Values for mean cell ages range from three to four days for high-
rate, 5 to 15 days for conventional and 20 to 30 days for extended
aeration activated sludge processes.
    It should be noted that the reciprocal of 0  is the net growth rate,
which is an important parameter for control of effluent quality as well
as the entire activated sludge process.
                                   27

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Sludge Volume Index
    .Sludge settling and compaction characteristics are & primary r@qui~
site to successful operation of the activated sludge process 0  Hith a
poor settling or bulking sludge 5, solids carry-over will contribute to the
effluent BOD and suspended solids „  Poor sludge compaction id. 11 result in
a low concentration of return sludge solids „ which in turn will limit the
concentration of mixed liquor suspended solids in the aeration 'basin.,
    Sludge volume index,, SVI,, is defined as  the volume in milliliters
occupied per gram of activated sludge solids after a I0000^ml mixed liquor
sample has been allowed to settle in a graduated cylinder for 30 minutes 0
The return sludge concentration , X „ can be expressed in terms of sludge
volume index, SVI8 ass
where         k = const ant „

Similarly j the cell  concentration in  the mixed liquor D X. B can be related
to the settleability of sludge as follows:

                                 Fr      106
                         Xl ° TFT^FT k SVI                         (30)

    It should be noted that when the  sludge volume  index  is  relatively
high;, -i«eo0 greater  than 1000 it is difficult  to maintain a  high cell
concentration in the mixed liquor even with a  high  return sludge ratio,,
Rf = Fr/F,
    Organic loading  velocity 5 L  „ appears  to affect the sludge settle-
ability and sludge volume index 0  At  low loading velocities  of lese  than
0,5 (mg BOD) /(sag VSS) (day) p  the  sludge volume  index has low  values and
                  •* '•
sludge bulking is rarely encountered „ As  the  loading velocity increases
to about 005  (mg BQD)/(mg VSS) (day) 0  the sludge volume  index increases
and an unstable settling condition  is approached,,   Activated sludge  sys-
tems  loading  velocities  in the  range  of 0,5  to 2.0  (mg  BOD)/(mg VSS) (day)
could have sludge bulking  problems,

                                    28

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                              SECTION VI
             EXPERIMENTAL PROCEDURE AND ANALYTICAL METHOD

FACILITIES
    Construction of the treatment facility for the City of Chino started
in I960,  The initial facility consisted of one primary sedimentation
tank, two oxidation ponds, one chlorination tank;, one anaerobic digester,
three sludge beds and a control building.  The design capacity of the
                              3
treatment facility was 0.044 tn /sec (1 mgd) .
    To evaluate the potential of the optimum performance activated sludge
system, construction of an activated sludge facility was completed in
1969 with the assistance of an EPA demonstration grant.  The new facility
includes two additional primary sedimentation tanks, three aeration basins,
vibratory separation screens, two secondary clarifiers, chemical feeding
equipment, a small-scale rapid sand filter bed, three small simulated
recreational test ponds and a laboratory.  The additional facilities  con-
structed under this grant increased the design capacity of the plant  to
0.13 m3/sec (3 mgc).
     The existing treatment  facility  and demonstration  activated  sludge
facility are  shown by  a  block-line  diagram in Figure 30
Barmiriution
     Barminution  is a  unit  operation  for  screening  and  reducing  the  size
 of  larger  particles to  a predetermined size.  The  process  consists  of
 trapping oversize particles  on  a bar screen and  passing  a  rotating  cutter
 periodically  over the screen to reduce the size  of the particles  so that
 they will  pass through  the screen.   The  unit  is  a  Chicago  Pump  Model "C"
                                   29

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                                                                                                                           SWUNG POIilTS
u>
o
                                                                    POinUCTBOWE
                                                                     001 US
                                                                     LUllMflTE
                                                    	,	„	s?
                         COTE

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Barminutor for a 0.610-m (24-in.) channel and has a maximum continuous
                        3
flow capacity of 0.285 m /sec (605 mgd).  The unit is activated auto-
matically when a predetermined headloss occurs across the screen,,  The
bar screen opening in the barminutor is approximately 0.95 cm (0,375 in.)„
Provisions have been made in the barminution structure for influent by-
passing through a coarse bar rack of the barminutor during maintenance
periods.

Primary Clarifiers
    Primary clarifiers have been installed to remove settleable solids
for subsequent treatment by anaerobic digestion.  The existing primary
sedimentation tank and the two new clarifiers are 25.9 m (85 ft) long
and 4.88 m (16 ft) wide with an average depth of 2.59 m (8.5 ft) .  The
effluent weir system was designed for an overflow rate of 124 m  /(day)(m)
 [10,000 gal/(day)(ft)K
    The clarifiers are equipped with a  flight system which draws settled
sludge  to the inlet end of the tank and which also skims the surface of
the tank on their  return.  Sludge accumulates in a single hopper at the
head-end of the  tank where it is withdrawn periodically by means of a
                                 3
pumping system using  two  lD090-m /day  (200-gpm) WEMCO sludge pumps con-
trolled by a  sludge density meter.  The skimmings are removed by hand-
operated dipping skimmers to a sludge hopper equipped with a Is090-m /day
 (200-gpm) WEMCO  sludge pump.

Aeration Tanks
    Three aeration tanks  of varying size provided flexibility in operation
Aeration  tank volumes are 240S  708  and  477 m3  (63,300,  187,000  and  126,000
 gal), which  in various combinations at  a flow  of O.U m /sec (3  mgd) pro-
vided hydraulic  retention times  ranging from 0.5  to  3.0 hr.  The primary
 effluent  can  be  fed  to any or  all  tanks through meter gates.  Return
 activated  sludge can  be  introduced  directly  to  the  first  tank or can be
 added  to  the  effluent  from the  primary  clarifiers.
                                   31

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Aeration Equipment
    Careful consideration v&s given to the selection of aeration.G
ment for the proposed  accelerated high-rate activated sludge syafce
The new deep-come SXMGO~SIfc£AR mechanical aerators with dissolved
concentration control  Here  employed.  The dissolved oxygen concentration
Has sensed with  a Honeywell dissolved oxygen probe and was controlled
through an automated Heir that varies the submergence of the aerators in
order to maintain a preset  dissolved oxygen concentration.
    Three mechanical  aerators were used5 having maximum electrical energy
requirements of  11,  19 and  56 kw (15S 25 and 75 hp)s respectively; and
in addition, an  extra  impeller designed for a  45-kw (60-hp) driver was
purchased.  Each aerator is designed so it provides approximately ten
inches  of impeller  submergence.
     Anti-vortex baffles were installed in each aeration tank.  The
baffles  consist  of  two large crossed plates mounted on the bottom of the
basin beneath  the  aerator.

Solids Separation Facilities
    Four solids  separation  devices—-plain sedimentation secondary clari-
fiers „ vibratory screens „ pressure filters and dissolved air flotators—
were employed  for  the separation of activated  sludge during the study
periodo

Secondary Clarifiers—
    Two  circular clarifiers are  provided with  sludge drawoff by suction
from three  zones on each arm of  the clarifier. These  units are equipped
with provisions  for adjusting the flow  of each pickup  zone.  Each of the
two clarifiers  is  16„8 m (55 ft) in diameter and  has an average water
                   e'                                •     3
depth  of 2.7 m (9  ft). At  an influent  flow  rate of 0,13 m  /sec  (3 mgd),
                   '•         3   2                  2
the overflow  rat®  is  25 06 m /(m  )(day)  [630  gal/(ft )(day)] with  a weir
rate of 110 m  /(day)(m) [80900 gal/(day)(ft)]„ These  units are equipped
with a central feed well approximately  2.90 m  (9»5 ft)  in  diameter.
                                    32

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Vibratory Screen Facility—
    The SWECO vibratory screen separator was tested as a method for
rapidly separating and concentrating a substantial portion of the acti-
vated sludge and was followed by secondary clarifiers to capture the
fines passing through the screens.  The purposes for the vibratory screens
were  (1) to reduce the detention time for separating the mixed liquor,
thus  reducing the potential for anaerobic conditions and thereby reducing
the possible release of sorbed or incorporated nutrients from the acti-
vated sludge cells to the effluent;  (2) to provide a means for separat-
ing filamentous sludges should they develop under the high loading rate
conditions; and (3) to provide a mixed liquor separating system that would
be compatible with the goal of reducing the plant size.  A two-week trial
run on separating mixed liquor in a  nearby conventional activated sludge
treatment facility suggested that overflow rates with vibratory screens
could be two to three times the level of conventional gravity secondary
settling,,  Each screen unit was equipped with a spray system consisting
of nozzles mounted in a piping configuration similar to the spokes of a
wheel.  The system was automated so  that the sprayers would activate for
a short interval at an adjustable frequency.  Each screen was fed from a
common trough.  The flowrate of the  feed was controlled by an adjustable
V-notch weir.
    Eight SWECO vibratory screens were installed.  Six of the units were
mounted on  two  supporting beams and  two units were mounted over hoppers
leading  to  two  sludge pumps.  One pump was set  up to pump the sludge  to
the  digester  and  the  other  to return the sludge to the aeration tanks.
    Two  of  the  eight  screens were stacked  in series  configuration so  that
 the  screening could be done in stages.  These  two units were equipped
with 0.044-mm opening (325-mesh)  screens„  followed in one case by a
0.029-mm opening  (500-mesh)  nylon screen and in the  other case by a
 0.014- by 0.105-mm  opening  (720-  by  140-mesh)  dutch  twill stainless steel
 screen.   The  remaining six  screen units were equipped  as followss   two
with a 0.044-ram opening  (325-mesh)  stainless steel screens0  two with
 0.037-mm opening  (400-mesh) stainless steel  screens,  one with  0.029-mm
                                   33

-------
opening (500-mesh) nylon screens end one with 00014- by 0,105°mm opening
(700- by 140-sssh) dutch twill stainless steel screens,,

Pressure Filtraeioa Unit~~
    A small rapid eaad filtration facility was constructed to polish
secondary effluent before discharging into three small ponds„  The unit
consisted of a 00914~m (36=in0) diameter INFILCO standard rapid sand
filtero  The facility is equipped with a feed pump0 a backmsh storage
tank and pump, a chemical feed pump and a batch tank,

Dissolved Air Flotation Unit—>
    An EIMCO pilot dissolved air flotation plant was leased in an effort
to thoroughly investigate  alternative solids separation systems„  The
pilot unit was approximately 1C52 m  (5 ft) in diameter and was equipped
with a complete float skimming system, bottoms rakes and a drawoff for
settled solids o  The unit  was also equipped with EIMCO°s two-stage pres=>
surization system for dissolving air in a recycle stream drssm from the
effluent of the unit.

Chlorination Facilities
    Existing chlorination  facilities were enlarged by the addition of
                                                                   3
another W & T A~731 V-notch 400-16 Chlorinator,  The existing 108-m
(28s600-gal) chlorine contact tank was retained,, which provide© retention
time of 1308 minutes at  a  flow rate  of 0013 m /sec (3 mgd)0

Chemical Feed Facilities
    A chemical  feed system was installed as a backup to aid in the overall
wastewater treatment0 particularly if polymer aids were needed for mixed
liquor separation or chemical treatment was needed for phosphate removal<,
The overall Prado Dam  (Chino area) plans called  for using the plant efflu-
ent for recreational purposes>  The  chemical feed facilities were designed
so that polymer, aids and/or chemicals could be added at any point in the
treatment facility  (from raw wastewater to secondary effluent)„  Due to
time constraints, the  chemical feed  system was not used extensively during
the 15-month study»
                                   34

-------
    The chemical feed facilities included a 1.08-ra  (285-gal)  storage
              3
tank, a 0.12-m  (33-gal) reserve tank and a variable-speed positive-
displacement pump which could be paced to the plant influent flowrate.
The chemical feed facilities also included a variable-speed pumping unit
                  2
and a  lined 15.1-ro  (4,000-gal) liquid chemical storage tank.

Recreational Eutrophication Ponds
    Three existing oxidation ponds of 3,750-, 3,750- and 23,400-m
[3.04-, 3.04- and 19.0-(acre)(ft)] capacity, respectively, and 1.1-m
(3.5-ft) deep were augmented with three simulated recreational ponds.
The simulated recreational ponds are 1.1-m (3.5-ft) deep and possess  a
                                3
capacity of approximately 740 m  [0.6(acre)(ft)] each.  The purpose for
the recreational ponds was to study the suitability of using the plant
effluent for recreational purposes.

OPERATION PROCEDURE
    The operation procedure for the optimum  activated sludge system con-
sisted of two phases—accelerated activated  sludge operation and testing
of alternative  solids separation  systc?ms  during the  15-month study.
    The raw sewage  from the. City  of Chino entered  the rectangular  pri-
mary  clarifiers through a barminutor.   Settleable  solidsj,  removed  in  the
primary clarifiers,, were pumped to an  anaerobic digester,  while  clarified
wastewater was  pumped  continuously to  the aeration tanks.   Constant  hy-
draulic flowrate was achieved by  utilizing one  aeration  tank as  a  pri~
mary effluent  equalizing basin from which the  primary  effluent  could be
pumped at a  constant flowrate to the  aeration  system,,  Mixed  liquor
 from the  aeration tanks was introduced to alternative  solids  separation
 systems,  from where return  activated  sludge  was pumped  continuously to
 the  aeration tanks.   Sludge wasting  was accomplished by  pumping directly
 from the  return activated sludge lines.  Digester supernatant was  not re-
 cycled to  the  plant but was  discharged directly to the  oxidation ponds.

Steady-State  Operation
      Steady-state activated sludge operation is desirable for characteri-
 zing biological oxidation kinetics.   Theoretically„ the substrate and
                                    35

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nutrient input concentrations, tlie. active biomass concentration, the
hydraulic residence time,, tlie return activated sludge flowrate8 the dis-
solved oxygen concentration and temperature should be controlled at 'con-
stant levels for complete biological kinetic analysis.
    By directly controlling the hydraulic residence time, the activated
sludge concentration and  the dissolved oxygen concentration in the mixed
liquor, a series of presumed steady-state operations Here completed during
the study period,.  Steady-state for the purposes of this study was defined
as a period where IB the hydraulic  residence tints, the substrate concentra<=
tion in the primary effluent and the biomass concentration in the mixed
liquor, determined at  daily intervals, did not vary more than ±20 percent
from a mean value „  The variation  of each parameter was required to be
random,, i0e., each parameter could not exhibit a consistent upward or
downward trend.

Sampling and Metering
    The sampling system designed for Chino contains five basic elements:
a controllers, a positive-displacement pump, a  three-way solenoid valve„
a triggering clock and a  refrigerator.  When in operation the  controller
receives a signal from a  selected  flowmeter and paces the withdrawal
rate of the sampling pump to  the flowrate.  The pump  delivers  a contin-
uous stream to ,ja  ths:ee-=way  solenoid valve which is  open to waste'.  The
triggering clock diverts  the  stream to  the  refrigerated sample bottle  for
a short fixed interval at an  adjustable  frequency.  This  automatic  saa~
pling system was  installed  to  sample  the  primary  effluent, mixed liquor9
secondary effluent and the  return  activated sludge  from  the  secondary
clarifiers.
    All watering  in  the  facility was  performed by Venturi metering  sys-
tems with a continuous backflow of wash water  through the meter.   Raw
sewage input flowates 0  flowrates  of  primary effluent to  the aeration
tanks, return activated  sludge flowrates,  waste sludge flowrates  and pri-
mary sludge pumping  flowrates were metered and recorded.   Table 1  presents
the location of sampling and metering stations at the plant.
                                    36

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                          Table !„   PROCESS MONITORING CHARACTERISTICS AND DAILY ROUTINE LABORATORY ANALYSES
              Process Location
   Flowmeter
     Sampling
             Analyses
              Priaary effluent
Venturi  flowmeter
Automatic recording
              Milted liquor
Automatic sampling
and  refrigeration
                              Grab sampling

                              Automatic sampling
                              and refrigeration
u>
              Secondary effluent
                              Grab sampling

                              Automatic sampling
                              and refrigeration
              Return activated
                sludge

              Haste activated
                sludge
Venturi floirester
Automatic recording

Venturi flowmeter
Automatic recording
Grab sampling

Automatic sampling
and refrigeration

Automatic sampling
and refrigeration
 Suspended solids (SS)
 Volatile suspended solids (VSS)
 Biochemical oxygen demand (BOD
 Chemical oxygen demand (COD)
 Total and dissolved KJoidalil nitrogen
 Total and dissolved total phosphate
 Dissolved NO"  NO"  and P0,=
                           Mixed liquor volatile suspended
                             solids (MLVSS)
                           Mixed liquor suspended solids  (MLSS)
                           Temperature
                           Sludge volume index (SVI)
                           Total and dissolved Kjeldahl nitrogen
                           Total and dissolved total  phosphate
                           Biochemical oxygen demand  (BOD)
                           Chemical oxygen demand (COD)
                           Dissolved NO",  NOT, and fO,=

                           Suspended solids  (SS)
                           Volatile suspended solids  (VSS)
                           Turbidity
                           Biochemical oxygen demand  (BUD)
                           Chcmlral oxygen demand (COL))
                           Total and dissolved Kjeldahl nitrogen
                           Total and dissolved total  phosphate
                                                                                           Dissolved N0~t
                                                                       NO'
                                               and PO  =
Suspended solids (SS)
Suspended solids (SS)

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ANALYTICAL METHODS
    A summary tabulation of the daily,, routine laboratory tests  performed
on the various process stream samples is presented in Table 1.
    Wherever possible,, Standard Methods for the Examination of Watex and
Wastewatere 13th edition (Reference 16) was followed for substrate,
nutrient and biomass measurements0  Details of nonstandard analytical
methods are presented in Appendix A,
Substrate Analyses
Chemical Oxygen Demand (COD)-°
    Chemical oxygen demand was determined by dichromate reflux method
according to Standard Methods for the Examination of Water and Wastewater
(Reference  16)0
Biochemical Oxygen Demand  (BOD)°-
    The five-day biochemical oxygen demand determination was mad© accord^
ing to' the  procedure outlined in Standard Methods for the Examination of
Water and Wastewater (Reference 16) ,  Dissolved oxygen measurements were
made using  a polarographic  dissolved  oxygen probe,
Nutrient Analyses
Total Kjeldahl Nitrogen—
    Total Kjeldahl nitrogen was determined using  the  procedure  outiiraed
in FWPCA Methods for Chemical Analysis  of Water and Wastes  (Reference  17)«
Distillation was carried  out  at a  pH  of 9o5 and the ammonia content  of
the distillate was measured titrimetrically.
Nitrate Nitrogen^-
    Nitrate nitrogen was  determined using  the procedure outlined  in
Standard Methods for  the  Examination  of Water and Wastewater (Reference
16)o  Color produced by  the reaction between  nitrate  and phenoldisulfonic
acid was measured with a  Bausch and Lomb Spectronic 20  at a waveleag£h of
410 my.
                                  38

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Nitrite Nitrogen—
    Nitrite nitrogen was determined according to analytical methods out-
lined in FWPCA Methods for Chemical Analysis of Water and Wastes (Refer-
ence 17).  The color developed by diazotization of the water with sul-
phanilamide and then coupling with N-(l-naphthyl)ethylenediamine was
measured using a Bausch and Lomb Spectronic 20 at a wavelength of 540 my.
Orthophosphate—
    Orthophosphate was determined using the stannous chloride method
listed in  Standard Methods for the Examination of Water and Waste/water
(Reference 16)„  Molybdophosphoric acid is reduced to the intensely
colored complex, molybdenum blue, by stannous chloride.  The color was
measured photometrically at a wavelength  of 690 rap.
Total Phosphate—
    Total phosphate was determined using  the persulfate digestion method
followed by stannous chloride Orthophosphate determination as outlined in
Standard Methods for the Examination of Water and Wastewater (Reference 16).
Biomass Analyses
Volatile Suspended Solids—
    Volatile suspended solids concentration was determined according to
the filtration procedure outlined in Standard Methods for the Examination
of Water and Wastewater (Reference 16).
Adenosine Triphosphate (ATP) —
    The adenosine triphosphate (ATP)  measurement procedure was  developed
from the work of Patterson, Brezonik and Putnam (Reference 18)  and Beutler
and Baluda (Reference 19)„   The amount of light prodiu i'd by firefly
extract is directly proportional to the amount of ATP added„  Detailed
procedures of the analytical method used are presented in Appendix A0

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 Dghydrosenase Activity —
      Triphenyl t®tr©xoliim chloride (TTC) is r
-------
    Daily calculations of net growth rates and hydraulic  residence times
and daily determination of mixed liquor volatile  suspended  solids  concen-
trations were used to establish periods of steady-state operation.
Steady-state conditions were defined as periods_JLn_whA.ch_theJnet_growth
rate, hydraulicresidence time or "MLVSS, did not vary .more. than-»±20,^peri:
cent. _Data obtained during these steady-state periods were used in sub-
^-—	—.—         "      ~       "                     -—*--.- * «.*   ._     ^  ^ ^
sequent calculations and kinetic evaluations.
Computational Methods
    A computer linear least-square  regression analysis was used to esti-
mate the kinetic constants  from  the linear cell continuity equation,
1/9C = ¥q - kd» and all  linear transformations from the Michaelis-Menten

 (Monod) equation s  q  = - — • -c  .   The linear transformations are:
                      IV   T O i
                       s     1
                                                                     (3U
           (2)               S  = () q - K                          (32)
           (3)                q = q - Kg(|-)                           (33)

     A nonlinear computer program (Reference 20) was also used to estimate
 the kinetic constants directly from nonlinear regression analyses.
                                   41

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                              SECTION VII
                         RESULTS AND DISCUSSION

WASTE CHARACTERIZATION

    The City of Chino is a community with a sewered population of approxi-
mately 16,000 residents plus an additional 2D000 prisoners of the Stats of
California;, and is served by the Chino Water Reclamation Facilities'„  The
only industrial operation served by the sewer system is a small rasat pack=
ing plantD which has a pretreatment system consisting of a small sedimen-
tation tank, a storage tank for impounding blood prior to removal via
trucks and a separate manure handling facility.  In general0 the waste-
water at Chino is similar to typical domestic waste as the industrial
contribution is small and partially pretreatedo
    No attempt was made to characterize the organic pollutant concentra-
tion in the raw waste reaching the treatment plant; all characterizations
presented herein8 except raw waste flow0 were made on primary effluent,,
Table 2 presents daily waste characterizations measured during the
steady-state periods.  Waste characteristics monitored include ran waste
flow, total BOD and COD, soluble BODC total and volatile suspended solidsB
and various nitrogen and phosphorus species in the primary effluent0
Average values are summarized in Table 3.
    The raw waste flow at Chino ranged from 0,0890 to 0,122 m /sec
                                                    3
(1085 to 2o79 mgd)„ with an average flow of 0,0972 m /sec (2022 mgd)„
Approximately one-tenth of  this flow was contributed by the prison com-
plex.  The contribution from the meat packing plant was estimated to be
also one-tenth of .the total flow.

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Table 2,  PRIMARY EFFLUENT WASTEWATER CHARACTERIZATION
Primary effluent
Date Raw sew- Total BOD, Soluble BOD
age flow, mg/1 ng/1
mVsec
16 Dec 70
17
18
19
20
21
31
2 Jan 71
3
5
15 Jan 71
16
17
18
15 Apr 71 0.102
16 0.119
18 0.0924
19 0.0964
09 Mav 71
11 0.0977
126
162
210
84
132
168
150
108
102
132
168
162
156
198
126
114
84
72
108
108
, Total COD,
mg/1
202
260
238
252
245
264
319
379
313
432
500
396
239
245
375
365
296
349
262
323
Total suspended
solids,
mg/1
130
78
68
135
110
125
105
105
143
123
210
140
223
220
117
83
78
107
73
131
Volatile suspended
solids,
mg/1
130
55
63
90
104
115
100
98
133
95
167
120
130
220
113
72
55
80
64
131

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                       Table  2  (continued).   PRIMARY EFFLUENT WASTEWATER CHARACTERIZATION
.Bo
Primary effluent
Date Raw sew=
age flow,
m3/sec
12 May 71
13
14
16
17
18
19 May 71
20
21
23
24
25
28
29
16 Aug 71
17
20
23
24
25
26
0.0920
0.0929
0.0920
0.0920
0.0872
0.0964
0.0933
0.0955
0.0937
0.0924
0.0889
0.0981
0.0933
0.0911
0.0823
Oo0924
0.0867
0.0810
0.0929
Oo0907
0.0907
Total BOD,
mg/1
168
144
108
84
96
96
90
108
138
162
160
156
98
108
120
94
108
150
126
138
153
Soluble BOD,
mg/1
«
—
—
—
—
— —
__
—
—
—
—
—
-
— —
60
—
59
57
45
57
63
Total COD, Total suspended
rag/1 solids,
402
510
415
308
318
364
357
390
584
460
423
389
560
364
342
290
279
341
265.
301
292
160
215
160
95
97
110
128
130
223
233
173
155
131
120
122
148
120
125
107
130
110
Volatile suspended
solids,
mg/1
160
215
160
95
97
110
98
65
195
185
158
113
110
105
90
127
80
. 93
70
88
75

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                        Table 2 (continued),,  PRIMARY EFFLUENT WASTEWATER CHARACTERIZATION
in
Primary effluent
Date Raw sew-
age flow,
m3/sec
28 Aug 71
29
30
31
5 Sep 71
6
9
11
12
13
14
16
17
19
20
28 Sep 71
29
10 Oct 7i
3
4
5
6
0.0915
0,0915
0.0841
0.0968
0.09x5
0.0823
0.0972
0.0964
0.0937
0.0933
0.0102
0.100
0.100
0.0990
0.0955
0.100
0.0959
0.113
0.110
0.105
0.115
0.0972
Total BOD,
mg/1
132
102
108
120
150
132
108
72
120
90
135
132
138
102
108
153
120
156
120
78
114
105
Soluble BOD,
mg/1
48
60
36
66
60
66
54
36
60
48
57
71
48
31
54
78
56
23
57
42
59
36
Total COD,
mg/1
322
258
277
454
306
293
281
279
328
308
313
314
267
278
313
337
358
582
307
319
304
339
Total suspended
solids,
mg/1
122
73
108
212
110
97
80
69
88
70
107
112
95
116
116
108
108
290
76
75
109
117
Volatile suspended
solids,
mg/1
75
63
82
155
87
79
67
59
69
57
48
84
80
88
88
79
84
240
49
63
71
81

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Table 2 (continued).  PRIMARY EFFLUENT WASTEWATER CHARACTERIZATION
Date
7 Oct 71
9
10
11
9 Nov 71
10
14
23
24
25
26
29
1 Jan 72
2
5
6
8
10
12

•Raw -sew- ••
age flow,
m3/sec
0.104
0.0986
0.0977
0,0942
0.0999
0.100
0.0950
0.0994
0.0981
0.0972
0.0920

0.111
0.122
0.116
0.104
0.101
0.100
0.102

Total BOD,
mg/1
96
87
108
144
113
116
88
96
79
111
114
79
160
152
105
156
84
128
113

Soluble BOD,
mg/1
53
59
63
81
66
72
42
64
44
72
50
47
71
68-
70
80
43
65
68
Primary
Total COD,
mg/1
380
333
347
395
408
382
317
321
303
332
328
276
491
365
353
393
363
363
404
effluent
Total suspended
solids ,
mg/1
78
72
109
137
112
120
74
103
108
147
115
57
238
113
159
162
185
110
112

Volatile suspended
solids „
mg/1
65
72
109
137
88
106
59
61
60
96
81
29
205
104
99
104
76
94
92

-------
                Table 3.  SUMMARY OF PRIMARY EFFLUENT WASTEWATER CHARACTERIZATION
Characteristic
Raw Waste Flow
Primary effluents
Substrate
Total BODa
Soluble BOD
Total COD3
Suspended solids
TSS3
vssa
Ni ,.1-ogen
total Kjeldahl nitrogen8
Jj11 -solved Kjeldahl nitrogen3
•'otal ammonia nitrogen*'
Dissolved nitrite and nitrate nitrogen
Total dissolved nitrogen0
Total nitrogend
Phosphorus
Dissolved orth 'phosphate
Total dissolved phosphate3
Total phosphate3
Unit
2
m /sec


mg/1
mg/1
mg/1
mg/1
mg/1

mg/1 as N
mg/1 as N
mg/1 as N
mg/1 as N
img/1 as N
mg/1 as N

mg/1 as P
mg/1 as P
mg/1 as P
Range
0.0890 - 0.122


72
23
202
57
29

24.8
24.1
18.1
0.00
24.1
24.8

7.4
6.6
7.1


- 210
- 80
- 584
- 290
- 240

- 61.1
- 47.8
- 32.2
- 0.64
- 47.8
- 61.1

- 17.0
- 25.2
- 27.5
Average
0.0972


122
56.9
345
125
100

38.8
33.5
23.0
0.08
33.6
38.9

11.3
14,8
17.8
Daily grab sample0         cSum of dissolved Kjeldahl nitrogen and dissolved nitrite and nitrate
                            nitrogen.
Three-day composite sample,, dSum of total Kjeldahl nitrogen and dissolved nitrite and nitrate nitrogen.

-------
    Total BOD in the primary effluent varied from 72 to 210 rag/1 with an
average of 122 rag/I0 of which 56,9 mg/1 or 4607 percent Has soluble,.
    Total COD rafflgsd from 202 to 584 mg/!0 with an average of 345
Assuming that 30 percent of the total BOD and COD is removed b
sedimentation^ thjj.® corresponds to a raw wastewater streng£h of 174
of BOD and 494 mg/1 of COD,  Total suspended solids in the primary efflu-
ent varied from 57 to 290 mg/lD with an average of 125 mg/lB of which
100 mg/1 or 80 percent was volatile0
    Average values of various nitrogen and phosphorus species concentra-
tions are presented in Table 3,

KINETIC CHARACTERIZATION OF ACCELERATED HIGH-RATE ACTIVATED SLUDGE SYSTEM

    By direct control of the hydraulic residence time and the return
sludge rate ands  thereby,  the mixed  liquor volatile suspended solids, a
series of nine periods of  steady-state operation were conducted during
the study„  Table 4 summarizes  the mean values of steady-state perform^
ance parameters of hydraulic residence timep mean cell ageD mixed liquor
sludge concentration  (MLVSS)„ substrate loading velocities„ temperature
and the number of steady-state  measurements  for each period.
    The activated sludge system was  operated at hydraulic residence times
of  from Oo97  to 5.16  hours„  The  mean  cell age of activated sludge in the
system was varied  from 0,446  to 32,4 days.   This wide range of mean cell
ages indicates  that  the  system  was  operated  from a very  low-rate system
(net growth  rate  = 0,0363  day"  )  to  a  high-rate system  (net growth rate ».
2016 day   ) „   Substrate  loading velocities ranged  from 00245  to 2061
(mg BOD)/(mg  MLVSS)(day) and 0,542  to  8,53  (mg COD)/(ing  MLVSS) (day) ,
The corresponding substrate  removal  velocities ranged from 0,229 to 2033
(mg BOD removed)/(mg MLVSS)(day)  and 0,365 to 6,57 (mg COD removed)/
(mg MLVSS)(day),  These  substrate loading and removal velocities corres-
pond  to process  substrate  removal efficiencies of  88 percent  BOD removal
and 75  percent  COD  removal,, which exceeded the goal of  80 percent BOD
removal  for  the  demonstration.
                                   48

-------
                  Table 4.   MEAN VALUES OF STEADY-STATE PERFORMANCE PARAMETERS
Steady-
state
run
la
2a
.3
4
5
6
7
8
9
Number of Temper-
steady-state ature,
measurements °c
10
4
4
8
8
22
11
8
7
18
18
19
20
20
25
23
20
18
Aeration
volume*
m3
939
939
240
240
240
240
240
240
240
Hydraulic
residence
time, day
0.215
0.173
0.108
0.0754
0.0725
0.0403
0.0412
0.0410
0.0442
Mean Net growth BOD loading COD loading
call age0 rate. MLVSS, velocity, velocity.
day day"1 mg/ 1 (mgBOD) / (mgVSS) (day) (mgCODyUgVSS ) (day)
32.4
16.6
3.17
1.58
1.39
0.737
0.525
1.57
0.0442
0.0363
0.0709
0.317
0.650
0.726
1.34
1.94
0.643
2.16
2520
3220
3690
2300
2550
1760
1050
2410
1120
0
0
0
0
0
1
2
1
2
.261
.307
.245
.659
.683
.70
.61
.03
.61
0.
0.
0.
2.
2.
4.
8.
3.
8.
542
622
872
09
39
33
53
45
05
System operated at low rate.

-------
    As discussed previouslyB conventional activated slud§@ systems operate
at organic loading velocities ranging from 002 fco 0,5 (mg ®0D)/(m
(day), with mean cell ages varying from five £o 15 days ®ad MLVSS's.
ing from 19500 to 3B000 mg/1.   On the other bands, high=rate systems
operate at substrata loading rates of 0,4 to 200 (rag BOD)/(mg MLVSS)(day)0
with mean cell ages of three to four days and MLVSS°s of from 500 to
!„500 rag/1,,  Comparing these operational parameters with the performance
parameters reported in Table 40 it is apparent that the system in this
study was operated from a very low-rate system (Steady=State Period 1)„
through a conventional activated sludge system (Steady-State Period 2)„
to a high-rate system (Steady-State Periods 3 through 9),
    Temperature of the mixed liquor varied on the average from 17 to 26°C
during the steady-state runs0  Although biological, hence activated sludgep
growth rate is a function of temperature, the effect of temperature on
system kinetic characteristics could not be evaluated in this study due
to limited and incomplete information on activated sludge system perform-
ance under various temperatures and system growth rates„
    The daily measurements conducted during the presumed steady-state
periods are presented in Table 50 which includes the steady-state MLVSS
concentration;, primary effluent substrate concentration (total BOD and
COD), primary effluent total and volatile suspended solids concentration,
secondary effluent substrate concentration (total and soluble BOD and
COD) „ cell concentration  (VSS)„ aeration tank volumes input rate of pri=
mary effluent,, return activated sludge flowrate and waste activated
sludge flowrate.
     Pertinent process characteristics and performance parameters are sum-
marized  in Table 6.  These  daily performance  characteristics are hydraulic
residence time,, mean cell age, substrate (BOD and COD)  removal and load-
ing  velocities and process efficiency (BOD and COD removals)„  In calcu-
lating the process characteristics and performance parametersD it was
assumed  that both soluble and  particulate BOD or COD in the primary
effluent are available substrate for cellular growth.   Because most par-
ticulates in secondary effluent are biological cells and effluent solids
                                     50

-------
Table 5.  SUMMARY OF STEADY-SLATE MEASUREMENTS
Date

lhDoc70
17Doc70
!SUcc70
19Dcc/0
20Doc70
210ec70
3VO..-C70
2Jan7l
3Jan71
5Jan71
]5Jan71
16Jan71
17Jan71
lSjAnn
-15,\pr71
lt>Apr71
18APr71
19Apr71
9May71
ll.M.iv71
UiUy7l
13May71
U>Uy71
In!l.iy71
17rtay71
18.-Uy71


Dace

16Dec79
170oc70
18Dec70
190ec70
20Dec70
21Dec70
31£ec70
2Jan71
3Jon71
5Jsn71
15Jan7i
16Jan?l
17Jan7J
18Jon71
~15Apr71
16Apr7l
18Apr7l
19Apr7l
9Ho 7J
JIW«V»I
1 'Hjyjl
13M£y71
liMav?!
loMjy71

IBMaJ?!
Primary Secondary Secondary
Steady- Affluent 	 i /etltuent effluent Return
atate VSS ,^-ML\(SS , / TSS , ) VSS, Sludse
period og/ll mg?\ \mg/l/ og/1 VSS. mg/1
\ ) ^ 	 X

1
t
1
1
1
1
1
I
1
1
$
2
2
3
3
3
3
4
4
4
4
4
4
4
4
Secondary
effluent
total COO.
mg/1

100
99
92
81
7S
76
106
84
94
84
298
156
130
128
115
113
101
10}
67
87
88
88
104
77
77
77
«"•— ••
130 1900 24
55 2270 18
63 2)f>0 13
90 2850 31
104 2980 25
115 2860 15
100 2010 32
9A 2530 24
133 2370 31
95 3060/ 32
167 3420 70
120 2960 42
130 3070 IB
220 3410x^?/^58
113 4290 35
72 3480 33
55 3610 23
80 3360/^^32
64 2270 16
131 2160 55
160 2180 35
215 2540 • 2
160 2220 32
9$ 2410 22
97 2420 21
110 2230 28
Secondary Secondary
effluent effluent
,soiuble\ total BOO,
(fcOD. og/'l 03/1
x 	 "
60 10
99 41
119 61
99 14
80 16
83 21
160 14
74 7
83. . 13
63/9^ 17
181 19
115 23
76 26
85 jt'Ji 7
83 18
89 19
75 , 14
77 V 1*
62 12
77 20
62 23
82 10
93 17
72 6
67 ', 12
72 1 * 10

11
15
a
15
25
15
30
22
24
29
31
18
58
35
31
22
27
14
12
27
2
26
16
21
18
Secondary
effluent
soluble
BOD. og/1

11
26
24
20
19
19
15
14
14
11
19
11
13
12
8
8
7
10
6
10
11
7
11
6
10
10
V M
4090
2270
5110
2960
1050
4210
4260
6300
4070
6300
8l700
9090
8680
7370
7000
7150
6380
6080
5750
5880
5530
5530
6760
6890
4300
Pri-.?ry
et fluent
llowrate.
a? /tic
jL/jLL^,
0182 L
182
182 s
182 ./
182 n
182 '
182
182
182
182
227
227
225
225
91
85 JfJ7
96 1 1 t>
96
136
131
131
134
131
131
136
131
Primary Primary
etlFlAient-v effluent
(total C0o)i total BOO,
\ og/1 ./ ng/1
**L "
202 "
260
238
252
245
264
319
379
313
432^-
7
500
396
239
245
375
365
296
3494
262
323
402
510
415
308
318
364
Return
oludge
flowrata.
El^/yl^.

129
135
145
144
140
146
134
129
134
124
119
149
141
113
62
' 66
69
62
79
76
76
76
72
71
72
62
t
>
126
162
210
H4
132
168
150
108
102
^ 132
cin
"t/
168
162
156
198
126
114
84
^ "
108
108
168
144
108
84
96
96
Haste
oludgo
flowrate.

fL/he*
.1
0.00
0.00
0.00
0.00
0.00
0.00
0.02
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.5 10
1.0 76.
1.* 71
1.* 7;
2.3
2.2
2,2
2.1
2.1
2.2 '
2.2
2.2


























Aeration
tank
voluea.


0939 £~
939
939
939
939
939 11
939 I"
939
939
939
939
939 - u
939 l~^
939
240
240
240
240
240
240
240
240
240
240
240
240
                                                        (p

-------
Table 5 (continued).   SUMMARY OF STEADY-STATE MEASUREMENTS
Soto
19>Uy71
20May7l
21Miy71
2J.'!.iy71
24Jiay71
25y71
2dMjy71
2
2«lt53iae
}gfi! @€@
ag/1
y
Q
8
14
16
S4
IS
&
-------
Table 5 (continued).  SUMMARY-OF STEADY-STATE MEASUREMENTS
Frloary Secondary Secondary
Steady* affluent effluent af Quant Return
•tate VSS, MLVSS. TSS. VSS. elutlge
Date period
2BS«p71 7
29Scp7l 7
10ct7l 7
30ct7l 7
40ct71 7
50ct71 7
60ct71 7
70ct71 7
90ct71 7
100ct71 7
110ct71 7
*So»71 8
10Nov71 a
UXovTl 8
23Nov71 8
24Nov71 8
25Sov71 8
26Nov71 8
29Nov71 8
lJjn72 9
2Jan72 9
SJan72 9
6Jan72 9
8Jan72 9
10Jan72 9
12JJD72 9
Secondary
affluent
total COO
Date Bg/1
28Sep71 112
29Sep?l 107
10ct71 109
30et71 120
40ct71 120
50«l71 127
6Oct71 101
70ct71 114
90ct71 @9
JOOesJJ 114
110ce71 —
?Ni>v7l 132
10::ow71 141
SiNov71 13S
2JSjv71 126
24Kov71 120
25Sow71 137
26Kov71 140
29Sov71 146
Uan72 \Q1
2Jsn72 132
5Jan72 168
6Jan7J i74
8Jan72 316
10Jan72 196
12Jan72 132
ag/1 og/1 Dg/1
79 1060 26
84 1190 19
240 1260 19
49 1010 46
63 1020 34
71 830 35
81 1080 17
65 1140 19
72 840 41
109 1050 12
137 950 IS
88 3280 28
106 3280 23
39 2530 40
61 2080 39
60 1890 36
96 2370 57
81 2050 30
29 1770 31
205 1190 62
104 1040 66
99 960 114
104 1280 65
76 1050 74
94 960 64
92 1380 55
Secondary Secondary
•ffluunt affluent
„ soluble total BOO,
COD, tag /I BS/1 .
86 34
80 23
71 23
78 19
84 23
85 26
77 23
. 84 19
71 23
102 21
108 $«-( —
113 36
110 32
102 29
89 31
83 37
93 32
106 5f,T 41
11? '«•' ' 28
Q8 41
79 30
82 46
107 48
109 28
106 &/; 30
117 «^> 18
ng/l
18
16
12
36
' 31
27
13
18
20
11
10
25
22
36
27
26
44
23
22
29
66
97
57
67
39
52
Secondary
offluene
oolublo
SOD. os/1
18
14
11
14
12
20
12
13
14
17
27
24
20
18
13
14
20
23
21
17
19
21
28
21
24
IS
Prioary Prleary
effluent affluant
total COD. total BOD.
VSS. ag/1 og/1
3030
3120
2950
2690
2690
2610
2710
2850
2800
2730
2550
8620
8870
6840
4830
5330
5740
5780
4450
3060
2570
1770
3630
3210
2380
3150
Prtmery
•ffluaae
glowrate o
13 ^
230
230
252
239
248
234
240
238
241
237
234
233
260
251
23$
237
234
236
237
233
249
200
234
230
173
230
337
358
582
307
319
364
339
380
333
347
395
403
382
317
321
303
332
3Z6
276
491
365
353
393
363
363
404
Raturn
oludgo
flowrsta
B3/hlr
136
136
136
123
125
123
123
127
127
127
127
136
136
131
134
136
136
136
134
131
131
136
148
108
108
114
a8/l
153
120
156
120
78
114
105
96
87
108
144
113
116
88
96
79
111
114
79
150
152
105
156
84
128
113
tfaeea
oludga
„ ilwroeo D
QJ/hr
3.6
3.6 .
3.6
3.3
3.7
3.4
3.6
3.3
3.7
3.6
3.7
1.4
1.3
1.4
l.S
1.3
1.3
1.3
1.3
4.S
4.1
4.0
4.1
4.1
4.1
4.1.



























Aaraiion
tank
voluna
eP
240
240
240
240
240
240
240
240
240
240
240
240
240
240
240
240
240
240
240
240
240
240
240
240
240
260
                            53

-------
        u
in

3a£<2
ri.6Dec70
17Dec70
18Dec70
19Dec70
20Dec70
21Dec70
31Dec70
2Jan71
t, 3Jan7l
5Jan71
15Jan71
16Jan71
17 Jan 71
18Jan71
^=-15Apr71
16Apr71
18Apr71
(__19Apr71
9May71
llMay7l
12May71
13ffcay7l
14May7i
16May71
17Ksy71

Ejydraulie
ffesideaea
6i®g0 I0
day
0.215
0.215
0.215
0.215
0.215
0.215
0.215
0.215
0.215
0.215
0.172
0.172
0.174
0.174
0.110
0.117
0.103
0.103
0.071
0.067
0.076
0.075
0.076
6.07S
0.073
Table 6.
,/
Isao X
cell
ag®0 .
®e» 
0.253
0.296
0.268
0.314
0.250
0.260
0.206
0.178
0.613
0.593
0.942
0.725
0.572
©.443
Oo4S5
Loading
LvCODC
0.494
0.532
0.468
0.411
0.382
0.429
0.737
0.696
0.613.
0.656
0.849
0.777
0.448
0.413
0.795
0.895
0.793
1.00
1.58
1.96
2.41
2.70
2,44
1.67
1.79
velocity B
LvBODd
0.308
0.332
0.413
0.137
0.206
0.273
0.347
0.198
0.200
0.200
0.285
0.318
0.292
0.334
0.267
0.279
0.225
0.207
0.649
0.654
1.01
0.762
0.636
0.455
0.541
COB removal
a££ieieffleys
*
73
* J
62
50
61
67
68
50
80
73
85
64
71
68
S5
78 '
76
75
78
76
76
84
S4
73
77
79
BOD removal
sffieicaeyo
I
91
84
89
76
86
§9
90
87
86
92
89
93
92
94
94
93
92
86
94
91
93
95
90
.93
90
Steady-
o£a£e
period
1
1
1
1
1
1
j.
1
1
1
2
2
2
2
3
3
3
3
4
4
• 4
4
4
4
4
                                          1.92
                                                        '•7

-------
Table 6 (continued).  SUMMARY OF STEADY-STATE PERFORMANCE PARAMETERS
Date
19May71
20May71
21Way71
23May71
24May71
25May71
28May71
29May71
16Aug71
17Aug71
20Aug71
23Aug71
24Aug71
25Aug71
26Aug71
28Aug71
29Aug71
30Aug71
31Aug71
5Scp71
'.Sep71
9Sep71
HSep71
12Sep71
13Sep71
14Sep71
16Sep71
17Sep71
19Sep71
lydraulle
residence
day
0.073
0.073
0.073
0.073
0.073
0.073
0.070
0.070
0.040
0.040
0.042
0.041
0.043
0.040
0.040
0.038
0.030
0.041
0.040
0.039
0.042
0.041
0.039
0.041
0.041
H.f)41
U.04U
0.040
0.040
Ksass
call
age 5
8cr day
1.36
1.35
1.51
1.57
1.57
1.29
1.27
1.20
0.545
0.625
0.700
0.788
0.692
0.508
0.754
0.776
0.817
0.753
0.715
0.874
0.775
0,848
0.812
0.411
0.719
0.871
0.740
0.806
0.860
Removal velocity,, Loading velocity „
^cooa 'BOD vcoflc VBOD
1.53
1.83
2.56-
1.96-
1.66
1.78.-
2.76'
1.76/
3.42
2.37
2.70
3.63
3.15
3.18
3.20
3.53
2.75
2.60
5.23
3.07
3.07
3.37
3.44
4.08
4.20
3.94
3.82
3.07 o,
3.12,
0.499
0.567
0.693
0.754
0.718
0.812
0.519
0.625
1.41
1.01
1.25
1.78
1.62
1.73
1.96
1.64
1,29
1.45
1.54
1.71
1.50
1.43
1.05
1.73
1.46
1.86
1.78
, 1.77
1.22
1.91
2.19
3.11
2.28
2.04
2.16
3.16
2.23
4.46
3.29
3.68
4.57
4.06
4.24
4.20
4.44
3.77
3.49
6.19
3.82
3.86
4.17
4.80
5.20
5.60
4.78
4.61
3.95
3.80
0.481
0.606
0.736
0.803
0.771
0.868
0.542
0.661
1.57
1.07
1.42
2.01
1.92
1.94
2.20
1.82
1.49
1.36
1.64
1.87
1.74
1.60
1.24
1.90
1.64
2.06
1.94
2.04
1.39
COD removal BOD removal steady-
efficiencyc, efficiency, state
I Z period
80
84
82
86
81
82
87
79
76
72
73
79
78
75
76
80
73
74
84
81
80
81
72
78
75
82
83
78
82
93
94
94
94
93
94
96
94
90
95
88
89
84
89
89
90
86
84
94
91
86
89
88
91
89
90
92
87
87
5
5
5
5
5
5
5
5
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6

-------
                             Table 6 (continued).   SUMMARY OF STEADY-STATE PERFORMANCE PARAMETERS
Wl



Dace

20Sep71
28Sep71
29Sep71
10ct71
30ct71
40ct71
50ct71
60ct71
70ct71
90ct71
100ct71
110ct71
9Nov71
10Nov71
14Nov71
23Nov71
2«Nov7l
25Nov71
26Nov71
2SNov71
Uan72
2Jan72
5Jan72
6Jan72
8Jan72
10Jan72
12Jan72
Hydraulic
residence
tins, e0
day

0.041
0.040
0.040
0.040
0.042
0.040
0.043
0.042
0.042
0.041
0.042
0.042
0.039
0.038
0.040
0.042
0.0/.2
0.043
0.042
0.042
0.039
0.040
0.050
0.043
0.040
0.058
0.040
(sag COD FQEOved)/
C te EC
19 applied)/
Mean
cell
age,,
eeo day

'0.881
0.493
0.556
0.649
0.434
0.337
0.482
0.590
0.569
0.407
0.589
0.562
1.81
1.74
1.38
1.63
1.44
1.35
1.60
1.60
0.538
0.388
0.364
0.456
0.353
0.486
0.535

Stessove
qCODs
\f\faf

3.26
5.96
5.88
10.2
5.40
5.73
6.64
5.86
6.19
7.52
5.55
7.24
2.29
2.16
2.14
2.63
2.74
2.34
2.56
2.11
8.57
6.86
5.69
5.24
6.06
4.64
5.21
'(qs m,VSS)(day).
'Ins EMS§)
(day) o

1 velocity.
W


1.31
3.21
2.24
2.90
2.50
1.61
2.24
2.08
1.74
2.10
2.06
2.95
0.697
0.762
0.696
0.940
0.815
0.900
1.03
0.778
2.83
3.19
1.76 •
2.34
1.50
1.88
1.78
J («g BOD re
lag B9B> a$

Loading
LvCODc


4.13
8.01
7.57
11.7
7.24
7.78
8.67
7.58
7.95
9.56
7.86
9.96
3.19
3.03
3.15
3.63
3.80
3.28
3.78
3.70
10.4
8.76
7.42
7.20
8.66
6.55
7.34 .
tanked) /(mf
lgiMc3d)/(jl£


velocity j, 000 reaoval
LvBODd efficiency.


1.42
3.64
2.53
3.13
2.83
1.90
2.71
2.35
2.01
2.50
2.44
3.63
0.885
0.921
0.874
1.09
0.991
1.11
1.32
1.06
3.19
3.65
2.21
2.86
2.00
2.31
2.05
j. MLVSS) (day)
1 MLVSS) (day)
Z
J-
79
74
78
88
75
74
77
77
78
79
71
73
72
71
68
72
72
71
68
57
02
78
77
73
70
71
71
o -
O

BOD reaoval
efficiency,,
2

92
88
88
93
88
85
82
88
86
84
84
81
79
33
80
86
. 82
82
78
73
89
83
80
'HZ-
75
©a
87



Steady-
state
period

«
7
7
7
7
7
7
7
7
7
7
7
©
3
C
8
e
Q '
• i
Q
9
9
9
.9
. S>
*
©



-------
concentration depends solely on the performance of the solids separation
system, effluent soluble substrate concentration was assumed to be the
limiting substrate concentration for the kinetic analysis.
Secondary Effluent Quality
    As mentioned previously, the secondary effluent substrate and solids
concentrations depend on the growth characteristics of the activated
sludge and the solids separation system performance, respectively.  In
this study, because the system was deliberately operated from a very
low-rate system to a high-rate system, the secondary effluent substrate
concentration varied with the system growth rate.  Secondary effluent
total BOD concentrations (Table 5) varied widely from 7 to 61 mg/1 and
no consistent trend could be delineated.  However, secondary effluent
soluble BOD  (Table 5) varied from 4 to 28 mg/1 and appeared to be a
function of  system growth rate.  This relationship will be discussed sub-
sequently in the kinetic analysis section.
     Secondary effluent  total suspended solids  in this study ranged from  2
to 114 mg/1  and volatile suspended solids varied from 2 to 97 mg/1 (Table
5),  despite  the use of  low—13 ra3/(m2) (day) [315 gal/(ft2) (day) ]—overflow
rates  in the secondary  clarifier.  No correlation could be drawn between
secondary effluent total or volatile suspended solids and system growth
characteristics.  The relationship between  secondary effluent solids con-
centration  and  solids separation system performance will be discussed sub-
sequently under the  evaluation of solids separation systems.
Active Biomass  Parameters—ATP  and  Dehydrogenase Activity
     In addition to  the  mixed  liquor volatile  suspended  solids  (MLVSS),
 adenosine  triphosphate  (ATP)  and dehydrogenase activity (measured  as
 triphenyl  formazan,  TF9 formed  per  hour) were used  to estimate the active
 biomass concentration,,   Although complete  daily ATP and dehydrogenase
 activity measurements were not  conducted throughout the study  period,
 11 steady-state ATP and dehydrogcmase activity measurements  were performed,
 and are reported in Table  7.
                                   57

-------
                       Table 7.  STEADY-STATE ACTIVE ORGANISM CONCENTRATION MEASUREMENTS
00
Steady °state
Date period
18 May 71
19 May 71
24 May 71
25 May 71
17 Aug 71
24 Aug 71
28 Aug 71
4 Oct 71
5 Jan 72
6 Jan 72
10 Jan 72
4
5
5
5
6
6
6
7
9 .;••;,.,;•.
9
9
ATP/MLVSS, . Effluent soluble Effluent soluble
(wg ATP)/ Dehydrogenase/MLVSS , COD, BOD 8
(mg MLVSS) (yg TF)/(mg MLVSS)(hr) Bag/1 mg/1
0.47
0.58
0.49
0.51
0.78
0.72
0.80
1.02
1.22
1.24V- v-
1.01
52.6
27.7
37.4
43.7
54.6
32.6
42.1
73o7
68.0-
50.4
72.6
72
70
79
70
81
59
66
84
82
107
106
10
6
11
10
5
20
13
12
. . 21
28
24

-------
    Previous research studies (References 21 and 22) have reported ATP
content and dehydrogenase activity of activated sludge as viability
measurements.  These studies found that the ATP content ranged from 0.2
to 0.3 (ug ATP)/(mg MLVSS) (Reference 21) and dehydrogenase activity
ranged from 31 to 83 (mg TF)/(g MLVSS) (hr) (Reference 22).  The ATP
content of the MLVSS in this study 10.47 to 1.24 (ug ATP)/(mg MLVSS)]
was higher than previously reported values s while the dehydrogenase ac-
tivities  [27.7 to 73.7 (ug TF)/(mg MLVSS) (hr)] were about the same as
the values reported by Ford, et al,   (Reference 22).
    ATP and dehydrogenase activity measurements were used in the kinetic
analyses and the performance characteristics based on ATP and dehydro-
genase activity are listed in Table 8.  These characteristics included
substrate (BOD and COD) removal velocity based on ATP and dehydrogenase
activity, net growth rate and effluent soluble substrate  (BOD and COD)
concentrat ions .
KINETIC ANALYSIS AND KINETIC CONSTANTS
    The kinetic characteristics of tho accelerated high-rate activated
sludge system were evaluated with respect to  the following  equations  and
kinetic coefficients and  constants:
     (1)   The cell continuity equation,

                             1/6C = Yq -  kd
    where Y  « yield coefficient
          k, ° decay constant.
     (2)   Michaelis-Menten  (Monod) equation,
                                         .
                                    s    1
                  maximum BOD removal velocity

           y » Yq = maximum specific growth rate

           K0 ° half -saturation constant.
            D

                                     59

-------
Table 8.  STEADY-STATE PERFORMANCE CHARACTERISTICS BASED ON ATP AND DEHYDROGENASE ACTIVITY
Date
18 May 71
19 May 71
24 May 71
25 May 71
17 Aug 71
24 Aug 71
28 Aug 71
4 Oct 71
5 Jan 72
6 Jan 72
10 Jan 72
Steady-state
period
4
5
5
5
6
6
6
7
9
9
9
qCOD(ATP)9 qBOD(ATP),
(mg COD removed ) (mg BOD removed)
(yg ATP) (day)
3.64
:.64
3.38
3.48
3.04
4.38
4.42
5.62
4o67
4.23
4.59
(yg ATP) (day)
1.07
0.774
1.47
1.59
1.29
2.25
2.05
1.58
1.45
1.89
1.86

day
0.521
0.738
0.638
0.774
1.60
1.45
1.29
2.24
2.75
2.19
2.06

-------
    (3)   Modified Michaelis-Menten (Monod) equation,
                                 - KCOD>
                      (K.-KCOD)
where     ^coD = raax*mum COD removal. velocity
          *    *
          p a Yq => maximum specific growth rate
          K  = half-saturation constant
           8
          K  n » nonbiodegradable COD concentration.
Evaluation of Cell Continuity Equation
    The cell continuity equation,  l/ec = Yq - k,, was used to estimate
the yield coefficient and decay constant.  Two substrate measures, BOD
and COD, were used as substrate parameters, and  the active biomass con-
centration parameters were expressed as mixed liquor volatile suspended
solids, ATP content and dehydrogenase activity.
MLVSS as Active Biomass Parameter—
    Least-square regression analyses of all steady-state measurement.!; re-
sulted in a yield coefficient of 0.793 (mg MLVSS produced) /(mg BOD removed)
as shown in Figure 4, and 0.293 (mg MLVSS produced)/ (mg COD removed), as
shown in Figure 5.  Although reasonable estimates of yield coefficients
were obtained with highly significant correlation coefficients
(R =» 0.865 for BOD basis and 0.871 for COD basis), relatively high nega-
tive decay constants were obtained (k, = -0.119  and -0.164 day   based
                                     a
on BOD and COD, respectively).  From a statistical regression stand-
point j, one of the primary causes  for the negative k,  appears  to  be  the
                                                                      -1
widely scattered data points  for  net growth rates greater  than  106  day
(cf.  Figures 4 and 5),  Consequently,  the  total  variation,, i.e.,, the sum
of the squares of the deviation of the values  of net  growth  rate from the
mean  net growth rate value „  of  these data  points could  markedly  affect
both  the slope  (yield coefficient) and  the intercept  (decay  constant) of
the cell continuity  equation (Equation  16) „
                                    61

-------
     3.0



     2.0



     2.1



     2.4



7    2.2
 S=»
 «S

"**   2.0



J3   i.g




~   1.0



§-   1.4



|   1.2


H3   | f)
era   l.w
I    I   1   i   I   1   !   I
S.  I    1   !
                       ©
                          STIW-STflTi

                          ITSaei-SlftTS
         JLJLJLJUUULJ
.2 8.4 0.6 0.8 1.0 1.2  1.4 LI !.§ 2.J  2.2 2.4 2.0  2.1 3.0 3.2-3.0  3.1 3.


         iii igam VELOCITY.

-------
 3=.
 fO
ts

C—
                                                     = 0.293 q
                                                  _ Q 293 (mg MLVSS produced)
                                                          (mg COD removed)
                                                   kd  = -0.164 day

                                                        (R = 0.871)
                                                   STEADY-STATE EXPERIMENTS AT HIGH  RATE
                                                   STEADY-STATE EXPERIMENTS AT LOW RATE
Figura   5.
                              34       56       78

                               REMOVAL VELOCITY, q      (mg COD removed)
                                                  COD,  (mg MLVSS) (day)

                Riot  of  cell  continuity using  COD  as substrate
                                                                              10
n

-------
    To check this possibility„ regression analyses tyes-s ©ad® on
values of nin© sEeady~Qtate periods0  Yield coefficients of 00922
(rag MLVSS produced)/(sag BOS rsaoved) „ as shcam in Figure 60 and 00328
(mg MLVSS produced)/ (@g COD removed) „ as ©ho*m in Figure 7B was1© obtained
with identical9 highly significant correlations  (R o 0,981,, p > 0099),
These values of yield coefficients are within the range reported by many
workers  (References 23D 24 and 25).. From the reported da£©0 it appears
that the yield coefficients of 0050  to 0,97 (mg  MLVSS)/(rag BOD removed)
and 0032 to 0.&6  (mg MLVSS)/(mg COD  removed) are applicable to the acti-
vated sludge treatment system of  domestic wastetrater.
    Corresponding values  of decay constants in the cell continuity equa=
                                                            —1
tion (Figures  6 and 7) Here found to be  0.027 and -0,023 day   based  on
BOD and  CODS respectively„  The decay constant of 0,027 day"  based on
BOD is of  the  same magnitude as reported decay rates.  Heukelekian at aJ0
(Reference  26) reported  a decay rate for activated sludge  of  00055 day
and Jenkins and Menar  (Reference  25) reported  a  decay rate of 0,015 day
                                         — 1
    The  negative  decay value, -0.023 day  based on  COD9 appears  to be
questionable,,  although negative values  for decay rates have been  reported
for bacterial  systems  (References 23 and 27),  Theoretically„ according
to the cell continuity  equation0  the value  of  k, should be positive rather
than negative.  The possibilities of varying decay rates and  varying  yield
coefficients  caused by  the temperature  variation in  mixed  liquor  (17  to
26°C)  through  the 15-month study  period may have caused a  negative k. to
result upon linear  regression  analysis,  Mo attempt  Has made  to evaluate
the effect of  temperature on these kinetic  characteristics due  to limited
and  incomplete data.
ATP and  Dehydrogenase as Active  Bioaiass Parameters
    The  yield  coefficients and  decay rates  based on  11  ATP and  dehydro-
genase activity measurements  were obtained  from regression analysis of
the  cell continuity equation,,  which are presented  in Figures  8D  9P 10
and  11,

-------
3.0
     2.5
     2.0
1.5
1.0
0.5
         1 = 0.922 q   -0.0273
         8C        BOO

         y _ g 922 (mg MLVSS produced)
                   (rag 800 removed)
          hd= 0.0273 day
                      -I
                  = 0.981)
0.5
                        ODD
                                                 •STEADY-STATE EXPERIMENTS AT HIGH RATE
                                                 o STEADY-STATE EXPERIMENTS AT LOW RATE
                                                                       1
                                         1.0               1.5               2.0
                                         VELOCITY,  q      (mg  BOD  removed)
                                                   BOD,  (mg  MLVSS)  (day)
                                                                                       2.5
Figure  @
        Cell  continuity equation for  mean  steady-state values  usinp  BOD as
                              substrate parameter

-------
ea
^    2
              T~     r
i       f
                • STEBP-STATE EX PER HOTS AT HIGH RATE
                o STEADV-STATE EXPERJBEIiTS AT LOI RATE
                                            1 = 0.328 D   +
                                          I     •  I
                7   Odll  e@s?t8nui ty aquation for  m@m §^®adlj/=i

-------
3.0
2.0
1.0
   i       r
                         !    '   I

                           * 0.439
                      (ATP)
                          dug ATP produced)
                          (rag BOD removed)
   «d = -o.
i       r
                  = 0.377)
i       r     T
          i       i      j	i
                                                     i       i       r	i
  0.2     0.4     0.®    O.B     1.0    1.2     1.4     1.6     1.8     2.0     2.7

             100 KEiOVAL  VELOCITY,

'igure   '
                    Plot  of cell  continuity  equation using-BOD-and ATP

-------
S3
•si
<33>
IUVJ1


0=
0=
^   LI
0=
                r~~i
    Fiiurt  I

-------
                      3.0
                      2.0
vO
                 C9
                      1.0
                                      I
I
        1 =24.3q(
0.834
                                                                rm
                                                                UF>
                                                                         (TF)
                                                                    = 24 3 0"E TF produced)
                         BOD
                                                                        '1
                                                            kd = -0.834 day
                                                                   (R= 0.417)
  0.01           0.02
BOD REMOVAL VELOCITY, q
                                                                0.03
                          0.04
                                                                   (mg BOD  removed)
                                                                   (/Jg TF/hr) (day)
                              Figure  10   Plot  of cell  continuity  equation using
                                        BOD and dehydrogenase activity
                                                                                         r)
             0.05

-------
     3.0
                       I       I       f
     2.0
•a:

-------
    Based on ATP measurements, as shown In Figure 8, a yield coefficient
of 0.661 (ug TF produced)/(mg BOD removed) and a decay rate of -0.439
day   were observed with a poor correlation coefficient  (R m 0.377).
Using COD as the substrate measure, as shown in Figure 9, a yield coeff-
icient of 0.629 (yg ATP produced)/(tog COD removed) and & large positive
decay of 1.045 day"  were obtained, with good correlation (R <= 00709).
    Poor correlation was observed using dehydrogenase activity as an ac-
tive biomass measure, as shown in Figure 108  A yield coefficient of 24.3
(ug TF produced)/(rag BOD removed)(hr) and a decay rate of -0.834 day"
were obtained (R = 0.417).  A good correlation (R » 0.678), however,
existed for the cell continuity equation based on dehydrogenase activity
and COD removal velocity, as shown in Figure 11.  The yield coefficient
and decay rate were 21.0 (pg TF produced)/(mg COD removed)(hr) and  -0.092
day  , respectively.
Evaluation of Substrate Removal Velocity and Substrate Concentration
Relationships
    Two different approaches were used  to evaluate  the substrate  removal
velocity and substrate concentration  relationships.  These approaches
were:
     (1)   By direct nonlinear regression analysis of  the Michaelis-Menten
           (Monod) relationship, q = qS^/(K  •*• S.)0  to determine  the maxi-
          mum BOD removal velocity, q,  and  half-saturation constant
           constant, K   and
                     5
     (2)    By direct nonlinear regression  analysis of  a modified  Michaelis-
           Menten  (Monod) equation,  assuming a certain  fraction of the  COD
           is nonbiodegradable0  namely,
                          	 COD'
                      q B TK—I~K—) + (s
                          (8   KCOD} * (S1
 where       ^    = nonb*°degradable <'•'>!) ^ont-pr.i ration
                                     71

-------
    To evaluate the Michfi®li@~Hsnt®n  (Monod) kinetic model ©ad its -modi-
fied equation  (Equation 34) 0 all ©t@®dy°state aessuresaeat® t?®ffe used in
the regression analyses,.  A poor correlation and uxir@a@oaal>ls estisaat© of
kinetic constants resulted, however;,  primarily dwe to %?ide scatter in the
data points , especially for HBeasur
-------
 (O
 €/»
 DO
                                                *  STEADY-STATE AT HIGH RATE
                                                  STEADY-STATE AT LOS? RATE
                                                    -4 13 (ag BOO removed)
                                                  BOO" '   (gig aiVSS)
                       10               20
                        EFFLUENT SOLUBLE SOD.
Fi
 hi
 12   Plot of ^lichagl is-^@nten  (Monod)
rate  activated  sludge  system using
        30              40
iOD,  f"1*/1)
   equation  for accelerated
    as substrate parameter

-------
iguire
 EFFUJiOT S
ftiehMli-s-^@nft@n (Nonod)- equation using BOD and ATP

-------
    Using dehydrogenase activity as an active biomass measure, a maximum
BOD removal rate of 0,101 (mg BOD removal)/(ug TF/hr)(day) and a half-
saturation constant of 39.9 (mg BOD)/I were obtained, as shown in Figure
14.  The maximum specific growth rate based on dehydrogenase activity
was estimated to be 2.45 day  .  Because of scattered data and a limited
numbei of data points, kinetic characteristics based on dehydrogenase
activity were inconclusive,

Modified Michaelis-Menten (Monod) Equation
    When COD was used as the substrate concentration parameter, a certain
amount of COD, Kr__, was assumed to be nonbiodegradable to activated sludge,
    Direct nonlinear regression analysis of the modified Michaelis-Menten
(Monod) equation (Equation 34) gave a maximum removal rate, q, of 8.35
(mg COD removed)/(mg MLVSS)(day)9 a half-saturations, KSS1 of 94,9 (mg COD)/I
and a nonbiodegradable COD of 19,9 mg/ls as shown in Figure 15.  The best-
fit equation that results is

                             8,35  (S,     -  19.9)
                                    1COD                            (35)
                        N   75°° +  CS1COD -  19°9)
    Multiplication of the maximum COD removal  rate0 q, by the yield co-
efficient „ Y9 produces a maximum specific growth rate of 2,74 day   based
on COD,  Although the kinetic  constants  q and  y appear to be slightly on
the low side., the values are realistic.
    Steady-state measurements  and  performance  parameters based  on ATP and
dehydrogenase activity also were evaluated with the modified Michaelis-
Menten  (Monod)  equation.  The  best-fit  equations obtained  are shown in
Figures  16  and  17  and are as followsi
                                                                   06)
                         ATP   949 + (S     + 6.5)
 and                    qTF  ° 942
                                     
-------
o
IS
 (So)

-------
ae
o-
53=
D=-
O
o
                                                            _  8.35(S, MD-19.9)
                                                        C00  (94.5 -
                                                                            C(JD
                                                                               - 19.9)
                                                        }   . 8 35 (mg COD removed)
                                                        COD   '   (rag MLVSS) (day)
                                                        Ks = 94.5  (rag COD)/I
                                                           •  STEADY-STATE AT HIGH RATE
                                                           o  STEADY-STATE AT LOW RATE
   Fii
                                EFFLUENT SOLUBLE  COD, Sj CQD  mg/l
                Plot  of modified  Michaelis-Menten (Monod)  equation  for accelerated
               -rate  activated sludge system using COD  as  substrate parameter

-------
C9
               ©
               &
               e
               =!>
               MJI
               CM
                        Flips'© II
                                                   usen'g

-------
•sj

V£>
          &
03

E
    0.14



    0.13



    0.12



    0.11






3  0.08
            o
t—

o
          •s*
          o
          •m
          —  ^CSO (TF)" (833 + 8.
    0.00



    0.07



    0.08



    0.03






    0 03



    0.02
                                             I

                                  o.§§4(sf CDO
                                                  -e-8.i)
                         a       - 0 584 dag COD
                          COP (TF)    '    (ajg TF/hr) (day)
                           - S33 (ag C00)/l
                            I
                                  I
                                                 I
                                          I
I
10      20




Figure n
                                30
                                                                          80
                                                    40       50      80       70

                                               EFFLUENT SOLUBLE COO.  S,  COQ mg/l


                                        Plot of modified Michael is-Menten (Morrod)  equation

                                                      and dehydrogenase  activity
                         100
no

-------
    Because of scattered data points (see Figures 16 and 17), both K
                                                                    3
and KCQJQ values, calculated on the basis of ATP and dehydrogenase activity „
appear to be unrealistic,.  Using previously determined ATP and dehydro=
genase activity yield coeffieients0 iae.9 Y T  <=> 0.629 (yg ATP produced)/
(rag COD removed) and ¥„_, » 2100 (\tg TF produced/hr)/(mg COD ressoved), the
maximum specific growth rate values Here estimated to be unrealistic
(27o4 and 12»3 day   based on ATP and dehydrogenase activity, respectively)

Summary of Accelerated High-Rate Activated Sludge System Kinetic
Characte ris tica  •
    Based upon both  theoretical analyses and practical considerations„
these studies confirm that one of the most important characteristics of
the activated sludge process  affecting both performance and operating
characteristics is the active biological biomass in the system*  Thusp
it is imperative that accurate estimates of the total active biological
bioroass in the system be obtained.  Three active biomass parameters—
MLVSS, ATP and dehydrogenase  activity—were considered in  the kinetic
evaluation of the  accelerated high-rate activated sludge system  for com-
parative purposes.
    Tables 9 and 10  summarize the kinetic characteristics  of the accel-
erated high-rate activated  sludge system based on ATP and  dehydrogenase
activity as  the  active biomass measures.  Because only  11  steady-state
ATP and dehydrogenase  activity measurements Here obtained  during the
study period,  the  kinetic  characteristics,  obtained  from regression anal-
ysis, appear  to  be questionable  on  a  statistical basis.
MLVSS as Active  Biomass  Parameter—
    Reasonable  estimates of kinetic constants  and kinetic  relationships
were  obtained using MLVSS  as  the  active  biomass measure.   A sumaary of
the most  probable*values for  the kinetic  constants  and  coefficients Y,
k.o q,  Ms,  K  and $LnT> are  presented in Table  11,   For  the  purpose  of
  u         8       (*U1)
comparison,  the reported values  of  activated  sludge  process kinetic  cci-
stants  are suosnacized in Table 12.
                                   80

-------
Table 9.  EVALUATION OF CELL CONTINUITY EQUATION USING ATP AND DEHYDROGENASE
                    ACTIVITY AS ACTIVE BIOMASS PARAMETERS
                             BOD as substrate parameter
                        Yield            Decay        Correlation
    Active biomass   coefficient9      constant,     coefficients
      parameters          Y           k, day              R
         ATP           0.661             -0.439          0.377
                      ATP produced)
                     ^
                  (mg BOD removed)


    Dehydrogenase     24.3               -0.834          0.417
      activity    (pg TF produced)
                  (mg BOD removed) (hr)
                        COD as substrate parameter
                   Yield            Decay        Correlation
                coefficient.     constanta      coefficient,
                     Y           k, day-1            R
                  0.629            1.045            0.709
               (pg ATP produced)
               (mg COD removed)
                 21.0             -0.092            0.678
                 ^ TF produced)
               (mg COD removed) (hr)
                                      81

-------
  Table  10.   EVALUATION OF MICHAELIS-MEHTEN  (MONOD)  EQUATION USIHG
         AND  DEHYDROGENASE ACTIVITY  AS  ACTIVE BIOMASS
   Active biomasa
     parameter
                          BOD as substrate parameter
               Maximum BOD
            removal velocity, q
       ATP             2.30


   Dehvdrogenase
      activity         0.101
(mg  BOD  removed)
 (yg ATP)(day)


    BOD  removed)
     TF/hr)(day)
                    Half -saturation
                                K
                                       5.1 mg/1


                                      29.9 mg/1
                      COD as substrate parameter
          Maximum COD
       removal velocity, q      constant, K
                   Ha If-saturation   Nonbiodegradable
                                        COD,  K
                                                         COD
     43.5
      0.584
    COD removed)
 (ug ATP)(day)


fag  COD removed)
     TF/hr)(day)
     942 mg/1
     933 mg/1
-6.5 mg/1


-8.9 mg/1
I
                                    82

-------
               Table 11.   SUMMARY OF MOST PROBABLE KINETIC GROWTH CONSTANTS OF ACCELERATED HIGH-
                                         RATE ACTIVATED  SLUDGE SYSTEM
        Kinetic  constants
                                                           Substrate parameter
            BOD
                                    COD
oo
        Yield  coefficient,Y
Decay constant, kd

Maximum substrate
   removal velocity„
 0.922
(mg MLVSS produced)
(rag BOD  removed )
                                            0.027 day
                                                     -1
                                            4.13
      (mg BOD removed)
       (mg :TLVSS)(day)
 Q 32g(jng MLVSS produced)
      Gng COD removed)


-0.023 day"1


      (mg COD removed)
                        8.35
                                                                                (mg  MLVSS)(day)
        Maximum specific
           growth rate,  \i

        Half-saturation
           constants,  K
                      s
                                                     -I
 3.81  day
26.4   mg/1
                                        -1
                        2.74  day
                       94.9   mg/1
       Nonbiodegradable  substrate
           concentrations,
                              19.9   mg/1

-------
                               Table 12.  ACTIVATED SLUDGE PROCESS KINETIC CONSTANTS
oo
Source
Heukelekian
Gram
Stack
Servici-Sogan
rtcWhorter-
Heukelekian
Eckho f f -Jenkins
Eckenf elder
Dryden
Haas-Pearson
Jenkins-Menar
Hopwood-Downing
Gram
Jenkins-Garrison
Eckhoff-Jenkins
MiddJebrook et al.
Reference
26
30
33
34
35
23
12
36
32
25
24
30
38
23
28
* . -1 K ._
q^ day s^ mg/1
Substrate BOD BOD
Domestic sewage
Skim milk 5.1 100
Glucose 3.0 355
Carbohydrates
Domestic sewage
Synthetic sewage
Pharmaceutical
Chemical
Domestic sewage
Domestic sewage
Domestic sewage
Domestic sewsg©
Domestic sewage
Domestic sewage
Domestic sewage
Y kd ,
SOD COD day"'1
0.50 0.055
0.48 0.045
0.42 0.087
0.34
0.33
0.46 0.08
0.645 0.37
0.77 0.2
0.45 0.05
0»53 0.33 0.001 - 0.015
0.97
.0.53
0.32 0.04
0.33 0.05
0.34 0.016

-------
Yield Coefficient—The yield coefficientB Ys defined as activated sludge
produced per unit of substrate removed, was found in this study to be
0.922 (mg MLVSS produced)/(mg BOD removed) and 00328 (mg MLVSS produced)/
(mg COD removed).  These yield values are in excellent agreement with yield
coefficients reported by many workers (References 22, 23 and 24), viz.,
6.50  to 0.97  (mg MLVSS  produced)/(mg  BOD removed) and 0.32  to  0.46
 (mg MLVSS  produced)/(mg COD  removed).  Middlebrooks  
-------
due to small magnitude  of  the decay  term,  (4) varying decay rat® as a
function of specific growth rate and temperature and (5) analytical
error,
Maximum Substrate Removal  Velocity and Maximum Specific Growth Rat_e°-The'
maximum substrate removal  velocity,  q, is  a growth constant calculated
from the M±chaelis=Menten  (Monod) kinetic  model and relates to maximum
specific growth rate, y =  YPO  Very  few workers have employed the
Michaelis-Menten  (Monod) equation in activated sludge kinetic analysis
                                     A     A
and therefore there are few imported q and M values „  Gram's data
(Reference  30) permit estimation of  a q of 3.0 (mg BOD removed) / (tag solids)
(day) and Benedek and Horvath (Reference 31) reported a q of 506 (mg COD
removed) / (mg solids) (day) .
    In this study, the  Michaelis-Menten (Monod) equation regression anal-
ysis yielded estimates  of  qB viz0, 4.13 (mg BOD removed)/(mg MLVSS)(day)
and 60 35 (mg COD removed) /(mg MLVSS)(day)0 The corresponding values of
maximum specific growth rates were 308l and 2.74 day  „ respectively 0
Theoretically, values of p calculated on a BOD or COD basis should be
identical.  The values  of  qrrir. and wrr.n  based on COD appear to be slight-
                                     \s UIJ
ly below expected values.   Comparing  the  daily steady-state  substrate
removal velocities  (see  Table 6) with the corresponding  values  of  q0 it
appears that  it was  possible to operate this  activated sludge system at
a very high growth  rate  (note especially  Steady=State Periods 7 and 9,
Table 6)0
Half-Saturation Constant and Nonbiodegradable Substrate  Concent rgttlon — •
The half-saturation constant, K „  is  the  limiting substrate  concentra~
                                8
tion which can support activated sludge growth at half the maxisaum growth
rate.  Again, very  limited information is available in the literature on
K  values for activated  sludge systems.  Pearson and Haas  (Reference  32)
 s
reported their best  estimates of K values of 80 (mg BOD) /I  and 225 (mg
COD) /I for the Whit tier  Narrows conventional  activated sludge plant 0
    From regression analysis of the Michaelis-Menten (Monod) ®quation0
the Kg in this study ware found to be 26.4 (mg BOD)/1 and 940S>  (ag COD)/i
Comparison with Kg  verlues reported by Pearson and Haas indicate® tha£  the

                                  86

-------
ratios of K  values from the two studies based on BOD (0.33) and COD
           s
(0.42) are very close.  It should be noted that the K  value is specific
for different waste characteristics, different environmental factors and
different activated sludge systems.  The relatively low values of K _.-
                                                                   SoUL)
and K _» indicate that both BOD and COD are adequate substrate parameters,
although BOD appears to be a better parameter than COD,  It also appears
that the organic substrate concentration expressed as BOD or COD was the
rate-limiting factor in the accelerated high-rate activated sludge system.
    In the modified Michaelis-Menten (Monod) equation (Equation 34), a
certain amount of COD is assumed to be nonbiodegradable in the system*
The nonbiodegradable COD concentration is specific for each organism
(activated sludge) and wastewater.  For the accelerated high-rate system
treating the wastewater from the City of ChinoB the nonbiodegradable COD
concentration is estimated to be about 20 mg/1.

SYSTEM KINETICS WITH OXYGEN TRANSFER

    The oxygen transfer requirements of an activated sludge system can
be expressed as the sum of oxygen  consumption for substrate utilization
and the oxygen requirements for sludge oxidation as follows;

                            U - aqX  + bk                            (38)
where     U  =  rate  of oxygen consumption
          a  =  oxygen requirements  per  unit  substrate removed
          b  =  oxygen requirements  per  unit  cell  oxidized
          q  =  substrate  removal velocity
          k. =  endogenous respiration rate
          X. =  mixed liquor  volatile suspended  solids concentration.

     To estimate the  quantity of oxygen  transferred  to the mixed  liquor
by the mechanical aerator,  the relationship  between oxygen  transfer rate
and aerator  power consumption should be identified. The oxygen  transfer
                                    87

-------
 rate is & function of the oxygen transfer coefficient,, the jpwes coasussp-
. £ion0 tejBBZKsrEfcuE1® sad the dissolved oxygen concentration gj?®di©a£ afc £h<2
 interface sad isa £h® bulk ©ix motor  efficiency
               k  s oxygen transfer ratep mass  0^  transferred/power inp.uto.
 For the EIMCO-SIMCAR aerators „  the gear  reduction efficiencyD  C,s  is
 approximately 0094; the motor efficiency is approximately 00925  and the
 oxygen transfer  rate Has  estimated to be in the range from 00610 to
 2»13 (kg 02)/(kw-hr consusaed)   1105  to 305 (Ib 02)/(hp-hr consumed)]
 (Reference 39).  '
     Based on several assumed values  for  the oxygen transfer capacities
 of the EIKCO-SBCCAR aerators such  as 0092,, 10220  10520 1083 ©nd 2013
 (kg 02)/(kw-hr coasisaed)  [loS,,  200,  2050 3»0  and  3»5 (Ib 0^ transferred)/
 (hp-hr consusasd)3 p the estiraated values  of the aeration coefticierats "a"
 and "bk " are susg^arised  in Table  13» Th® "a" values ranged from 0013.)
        d                                                  "•
 to 0«304 (rag 02)/{mg COD  removed)  or 0,328 to 00766 (mg 02)/(iag SOD re-
 moved) and the "b&d" values ranged from  0.311 to  00755 (mg 02)/(mg MLVSS)
                   . t

-------
                    Table  13.  OXYGEN  TRANSFER KINETIC CONSTANTS IN AEROBIC BIOLOGICAL PROCESSES
oo
vO
Substrate
Skim milk
Domestic sewage
Pr.iu and paper
Chemical
Kraft pulp
Domestic sewage
(this study)
11
it
it
11
Source
Gram (Reference 30)
Downing (Reference 40)
Eckenfelder (Reference 12)
Dryden (Reference 36)
Hazeltine (Reference 37)
Assumed oxygen transfer rate
2.13 (kg 02)/(kw-hr)
1.83 (kg 02)/(kw-hr)
1.52 (kg 02)/(kw-hr)
1.22 (kg 02)/(kw-hr)
0.92 (kg 02)/(kw-hr)
"a"
BOD COD
0.40
0.50
0.52
0.35
0.50
0.766 0.304
0.657 0.250
0.548 " 0.217
0.438 0.174
0.328 0.130
"hlf "
BOD
0.065
0.100
0.089
0^20
0.10
0.755
0.647
0.540
0.432
0.324
day
COD
_
-
-
-
-
0.725
0.62
0.518
0.414
0.311

-------
    Many workers (Seference© i20  30 and 40) have reported 'V md "bk.90
                                                                      &
values on a SOT  baoi®.   The typical values obtained fosr fchs coefficient
"a" range 2ro®-0-033 to 0080 (sag 02)/(tag BOD) for difftuserafc ©yafchefcic
substrates and Oo5  (tag 09)/(m§ BOD) for domestic semge (Inference 41).
                         A
Unfortunately 0. ©d published information is available for co©££ici©a£ ""a1"
values based on,COD as substrate  parameter.  Meanwhilep £hs: reported
"bk," values raag©  fgota 0,065 to  002 (mg .0»)7(mg MLVSS)(day)0
   Q             4                          &
ing to "b" value® of 100 to 1.44  (mg 02)/(tag MLVSS) „
    Comparing  the calculated "a"  and "bk," values with th© s©poirt©d
in Table  13B itxappears that "a"  and "bkd" values of 0.438  (sag 0'2)/(®g BOD
removed)  and 00<|32  (sag 0,)/(mg MLVSS) (day) 8 respectivelyB based on an
                <*•        «•
oxygen transfeffkrate of 1»22 (kg  02)/(kH=hr consumed) [2.0 (Ib 07)/(hp-hr)]
are close to reported values.  Table 14 presents the estimated oxygen trans-
fer rates based  upon 1022 (kg 02)/(to-hr consumed) [200 (Ib 0
transfer  rate  sn\d substrate (BOD.and COD) removal velocities0  this
of oxygen transferred ranged from 00210 to i096 (mg 02)/(mg MLVSS)(d©y)
and is a  linear  function of substrate removal velocities'g <5BOjj and <5COD9
as shown  in  Figures 18 and 19 0 respectively0
    Ths "bk."  values estimated from this study are high coaparod with
           Cl   *^
values reported1-'in  the literature 0  There are several explamsfciotas for
the high  "bk.1" valuess  (1) the assumed ossygen transfer coeff£c£emt oif
0.92  to 2.13 (kg 02)/(kw-hr)  [105  to 3»5  (Ib @2)/(hp=hr)] is sa over°
simplified  assumption because  the  oxygen  transfer  coefficient is not COSB
stant and is  a 'function of aerator type0  temperature and. oxygen conceta=
                 't                  •
tration gradient between the interface and in the mixed liquor g (2) this
negative  value of decay rate0  k.„  may influence the ordinate intercept
(bk,) of  the oxygen requirements equation (Equation 38) j and (3) the
decay rate  may vary with substrate removal rate or with specific growth
               } *
rate  such that  the assumption  of a linear relationship between oxygen
                >
requirements and substrate  removal rate  is questionablep especially ©t
low  rates o       ,-
                                     90

-------
                             Table 14.  OXYGEN TRANSFER KINETIC DATA AND SLUDGE VOLUME INDEX
ve
ec
16Dec70
17Dec70
18Dec70
19Dec70
20Dec70
21Dec70
31Dec70
2Jan71
3 Jan 71
5Jan71
15Jan71
16Jan71
17Jan71
18Jan71
15Apr71
16Apr71
18Apr71
19 Apr 71
9May71
1 l^lay 71
12May71
13May71
14May71
16May71
Power
II&&© ^£ui|p t£ «L OKA p
_
-
-
—
-
-
- '
678
654
677
794
567
670
719
489
478
562
384
432
460
477
459
475
441
T®rap@r©£<
•c

—
—
-
-
-
—
—
_
-
_
_
_
-
19.5
20.0
18.0
18.5
20.0
20.5
20.5
20.0
20.0
20.0
BOD removal
velocity s q,
ares, (mg BOD removed)
(mg MLVSS)(day)
0.281
0.278
0.366
0.104
0.176
0.242
0.312
0.173
0.172
0.18.4
0.25?
0.296
0.268
0.31'V
0.250
0.260
0.206
0.178
0.613
0.593
0 = 942
0.725
0.572
0.423
COD removal
velocity s q,
(mg COD removed)
(mg MLVSS)(day)
0.347
0.329
0.234
0.249
0.257
0.291
0.367
0.560
0.451
0.560
0.542
0.551
0 . 305
0.270
0.619
0.676
0.592
0.783
1.20
1.49
2.04
2.26
1.90
1.28
Oxygen transfer
rate, U,
(og 02)
(mg HLVSSHdayJ
JIL
. -
-
-
-
-
-
0.294
0.303
0.243
0.255
0.210
0.239
0.231
0.490
0.590
0.669
0.491
0.818
0.915
0.940
0.777
0.919
0.785
Sludge
volume
index
_
-
-
-
-
-
-
293
2'J2
251
234
233
257
.252
87
90
93
169
189
226
227
229
176
207

-------
Table 14 (continued).   OXYGEN TRANSFER KINETIC DATA AND SLUDGE VOLUME INDEX
Bae©
16Msy71
17May71
18May71
19May71
20May71
21£2sy71
23£3ay71
24May71
^ Cl^9 A W 7 1
^ jpjUfl y / i
28May71
29May71
16Aug71
17Aug71
20Aug71
23Aug71
24Aug71
25Aug71
26Aug71

29Aug71
30Aug71
31Aug71

f
BOB removal
. COD removal
velocity o q0
) -(tag; COD r-esaow
• °^s£rrf e;
r
Sludge
fe^=te ° i®d©s
441
470
471
457
488
474
446
446
464
473
• 464
372
382
377
380
435
425
433
543
363
448
. 478
20.0
20 J)
20.0
20.0
20.0
20.5
20.0
21.0
21.0
20.0
20.0
26.0
26.0
. 25.0
24.0
25.0
24.5
24.5
23.0
24.0
24,0
24.0
0.423
0.485
0,504
0,449
0..567
0.693
0.754
0.718
0.812
0.519
0.625
1.41
1.01
1.25
1.78
1.62
1.73
1.96
1.64-. .
1.29
1.15
1.54
1.28
1.42
1.71
1.53
1.B3
2956
0.96
1.66
1.78
2.76
1.76
3.42
2.37
2.70
3.63
3.15
3.18
3.20
. . 3.53
2.74
2.60
5.23
0.785
0.835
0.908
0.769
0.862
0.796
0.696
0.676
0.813
0,807
0.859
9,834
0,748
0.900
0.902
1.22
1.03
1.07
1.21
0..89
loOO
1.11
207
218
204
' 217
200
213
206
184
193
206
196
72
87
113
124
88
100
121
168
• '175
138
365

-------
                         Table 14  (continued).  OXYGEN TRANSFER KINETIC DATA AND  SLUDGE VOLUME  INDEX
u>
Power
consumption
Date kw-hr
5Sep71
6Sep71
9Sep71
115ep71
12Sep71
13Sep71
14Sep71
16Sep71
17Sep71
19Sep71
20Sep71
28Sep71
29Sep71
10ct71
30ct71
40ct71
50ct7l
60ct71
70ct71
90ct71
100ct71
110ct71
484
281
374
372
389
398
382
387
375
392
374
365
371
400
390
440
395
426
414
383
395
388
BOD removal
velocity, q,
TesjperatureB (mg BOD removed)
°C
23.0
23.5
25l5
24.0
25.5
26.0
26.0
25.5
25.5
23.5
24.0
23.5
23.0
23.0
22.0
23.0
23.0
23.0
23.5
23.0
23.4
23.5
(mg MLVSS)(day)
1.71
1.50
1.43
1.05
1.73
1.46
1.86
1.78
1.78
1.22
1.30
3.21
2.24
2.90
2.50
1.61
2.24
2.08
1.74
2.10
2.06
2.95
COD removal
velocity, q,
(mg COD removed)
(mg MLVSS)(day)
3.07
3.07
3.37
3.44
4.08
4.20
3.94
3.87
3.08
3.12
3.26
5.96
5.88
10.2
5.40
5.73
6.64
5.86
6.19
7.52
5.55
7.24
Oxygen transfer
rate, U,
(mg 02)
(mg MLVSS)(day)
1.03
0.671
0.970
1.09
1.09
1.27
1.02
9.978
0.699
0.928
0.862
1.49
1.35
1.36
1.65
1.85
1.73
1.70
1.57
1.96
1.62
1.76
Sludge
volume
index
412
323
171
168
184
199
272
935
549
577
463
581
483
434
756
724
826
708
696
283
707
808

-------
                        Table 14 (continued).  OXYGEN TRANSFER KINETIC DATA AND SLUDGE VOLUME  INDEX
VO
Power
consumption,
Date kw~hr
9Nov71
10Nov71
14Nov71
23Wov71
24Mov71
25Nov71
26Nov71
29Nov71
2Jan72
5Jan72
6Jan72
8Jan72
10 Jan 72
12Jan72
390
413
388
408
408
408
391
378
381
393
394
379
378
377
BOD removal
velocity , q,
Temperature 0 (mg BOD removed)
°C
21.0
21^0
21.0
20.0
20.0
20.5
20.0
21.0
18.0
17.0
17.0
18.5
18.0
18.0
(mg MLVSS)(day)
0.697
0.762
0.696
0.990
0.815
0.900
1.03
0.778
2.83
1.76
2.34
1.50
1.88
1.78
COD removal
velocity p q»
(mg COD removed)
(mg MLVSS) (day)
2.29
2.16
2.14
2.63
2.74
2.34
2.56
2.10
8.57
5.69
5.24
6.06
4.64
5.21
Oxygen transfer
rate, Us Sludge
(mg D£) volume
(mg W.VSS)tday
0.511
0.541
0.659
0.843
0.926
0.740
0.821
0.916
1.37
1.77
1.32
•1.55
1.69 '
1,17
) index
104
86
422
71
93
110
146
276
=
39
39
25
35
33

-------
tao
 CM

C3


 t>0
                                 a = 0.438 (Rig




                                 bkri =0.432 (mg 07)/(rog IU?SS)
                                   U o          i
                             VELOCITY  a     (tag  JOB  removed)
                                     i  TO* iRip*  V™ " ™*  Rtrir II/Aif"^T™™7TT^^^TC
Figure  IS   Re I at ionslnip
                                            oiiygso  transfer

                                   removal  velocity
                                   95

-------
=3
o
SO
 Cry.
es
(VAJ)
(UL,
c=
ivn
• = 8.1M (Bg B2)/(B| S8B
    = 0.414 (si 02)/(Q8
           '(B-= f.PI)

-------
NUTRIENT REQUIREMENTS AND REMOVAL
    In addition to organic substrate (carbon source), organisms require
a complex set of nutrients and micronutrients for cellular growth-  The
principal nutrients required for activated sludge are nitrogen and
phosphorus.  Therefore, nitrogen and phosphorus requirements„ removal
efficiencies and removal velocities are of primary concern in activated
sludge process analysis.
    Table 15 presents data on the total and dissolved nitrogen species
(Kjeldahl, ammonia, and nitrite and nitrate) and phosphorus species
(total phosphate and orthophosphate) in the primary  and secondary effluents^
Nitrogen
     The concentrations of various total and dissolved nitrogen species
(Kjeldahl, ammonia, and nitrite and nitrate) in the  primary and secondary
effluents were relatively constant during  the 15-month study period, as
shown in Table 15„  Average total and  dissolved nitrogen  concentrations
in  the primary and secondary effluents are summarized in  Table 16„
Kjeldahl nitrogen represented 99„8 percent or 38.8 mg/1 as N of the
average total nitrogen content  (38.9 mg/1  as N) in the primary effluent,
and consisted of 59.2 percent ammonia  (23.0 mg/1 as  N) and 40.6 percent
organic nitrogen (15.9 mg/1 as  N)„  The average dissolved nitrogen  frac-
tion in the  primary effluent  (33.6 mg/1 as N) was approximately 86,4
percent of  the total in which 86,2 was dissolved Kjeldahl nitrogen, which
consisted of 59.2 percent ammonia  (23.0 mg/1 as N) and 27 percent organic
nitrogen  (10.6 mg/1 as N).  Only minor amounts of combined dissolved ni-
 trite and nitrate  (0.08 mg/1  as N) were present in the primary effluent.
In  the  secondary effluent,  average  total Kjeldahl nitrogen  (29,9  mg/1  as  N)
comprised 97,1 percent of the total nitrogen  (30.8 mg/1  as N)0 and  average
dissolved Kjeldahl nitrogen (27,9 mg/1 as  N) comprised 9006  percent of the
 total nitrogen.  Ammonia  in the secondary  effluent was present totally as
 dissolved  ammonia  (20.9 mg/1  as N).   The average  dissolved nitrate  and
 nitrite increased  from 0.08 to  0,90 mg/1 as N.  This indicates  that a  minor
 degree of nitrification  took place  even  at the high  organic  loading veloc-
 ities and growth rates experienced  by the  system.
                                  97

-------
         Table 15 „   STEADY-STATE NITROGM AS® PHOSPHORUS
KJoldohl
ofterosen « eg ' 1 oo K
Date
16Dec70
17Dec70
180ec70
190GC70
20Dsc70
210QC70
31D@c70
2Jan71
3Jan71
5Jan71
15Jan71
16Jan71
17Jan71
18Jan71
15Apir71
16Apr71
18Ap?71
19Apr71
9Say71
IVlayTl
12May71
13May71
14May71
16May71
17May71
18Hay71
19May71
20May71
2 Way 71
23May71
24May71
25May71
26May71
29May71
16Aug71
17Aug71
20Aug71
23Aug71
24Aug71
25Aug71
26Aug71
28Aug71
29Aug71
30Aug71
31Aug71
A
27.1
38.1
44.0
33.3
38.9
37.6
39.9
30.3
34.7
38.0
47.1
50.4
43.8
31.8
40.3
41.8
37.5
40.0
35.1
37.5
44.3
51.7
43.8
37.5
38.2
40.2
40.8
40.8
46.3
42.0
40.2
39.6
45.7
37.7
38.4
35.3
37.1
36.5
35.3
38.4
37.1
38.9
24.8
34.0
45.2
a
.
-
-
-
-

-
_
-
-
-
-
- .
-
_
-
-
-
_
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
32.3
31.6
30.9
35.3
31.5
34.7
32.2
- .
24.1
29.1
34.0
C
31.0
36.2
38.9
31.8
31.1
30.5
31.4
33.2
32.4
25.3
42.4
33.2
30.5
36.5
_
-
-
-
27.1
27.7
24.6
28.9
34.1
28.8
29.8
28.0
30.4
29.8
31.7
26.8
29.8
29.8
31.7
28.6
30.3
27.8
27.8
30.3
27.8
30.3
25.4
27.2
30.3
30.3
27.2
0
34.2
38.1
47.3
33.8
31.8
32.4
30.7
30.7
31.4
28.0
33.8
31.8
28.5
31.8
31.5
32.0
28.9
28.3
25.8
27.1
23.4
28.3
31.7
27.7
29.6
28.0
28.6
29.8
29.2
26.8
30.4
28. &
28.0
25. 6
22.9
23.3
24.3
24.8
23.5
22.9
21.7
24. S
25.4
26.6
26.6
E3R/1 OS W
A
23.3
21.3
23.6
21.0
23.3
18.8
32.2
25.7
23.7
27.6
28.6
20.9
25.6
21.6
23.9
•>
24.9
-
22.2
-
-
23.1
-'
24.0
-
-
-
23.6
-
23.4
-
- ..
'. =
—
c,
•-
«•
-
-
-
22.0'
-
21.7
-
-
C
24.2
28.1
29.4
23.0
23.0
_«.
20.7
25.0
23.7
22.7
20.9
22.9
16.9
18.6
23.0
-
23.1
-
20,3
=
-
19.1

22. 0
-
-
-
21.6
-
21.3
-
-
-
-
_ .
-
-
-
-
-
17.0
•=•
17.0
-
-
D
24.7
28.4
29.4
23.0
23.3
21.7
22.1
24.3
24.1
23.6
22.6
23.6
17.3
17.9
23.3
- »
23.1
-
20.0
-
-
16.6
-
22.5
-
-
-
21.6
-
20.4
-
-
-
-
_
-
-
-
-
-
17.9
-
16.4
-
-
Hit
a&
OB/1
B
0.04
0.01
0.00
0.02
0.25
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.30
0.11
~
0.00
-
0.00
=
—
0.01

0.01
-
-
-
0.00
-
-
-
-
-
-
•
-
-
-
-
-
0.04
-
0.00
-
-
ffGfce 6
EiiEQ D
as N
0
.
-
-
-
-
»
0.00
0.50
0.00
0.66
1.23
2.11
1.61
1.16
0.11
-
0.00
-
0.03

-
0.04
-
0.49
-
-
-
0.002
-
-
-
-
0
-
—
-
- -
-
-
-
0.67
-
0.84
-
-
Uoeol Ktocfjhoea o
OQ/I as P
~S
11.8
10.3
1@.@
15.3
20.0
21.5
20.0
23.3
16.0
15.4
18.5
19.0
27.5
24.0
18.8
23.0
20.8
17.3
10.3
10. S
17.8
24.0
23.0
13.3
21.0
21.5
22.0
20.0
20.0
21.0
20.0
13.3
13.8
23.0
24.3
20.0
13.8
15.8
16.5
23.8
19.0
19.3
17.5
20.0
20.0
tf C
17.6
° 20.S
- 13.0
- 14.0
- 17. @
- 13.8
'- 16.0
- 17.3
- IS .8
- 18.7
- 3$.S
- 19.0
- 21.0
- 22.0
- is. 8
- 15.3
- 14.5
- 13.3
CS> <30
- 13.8
'- 12.5
S.3
14.8
- 13.3
- 21.0
- IS. 3
- 14.8
- 14.3
- 14 o5
- 11.5
•- 13.0
- 12.0
- 12,8
- 14.8
22.0 18.8
20.0 13.3
11.8 12.3
13.4 13,0
15.8 15.1
23.0 17.3
19.0 19,5
17.0 11.0
1&.9 14. Q
20.0 13.1
20.0 13.3
y
._
»
13. Q
12. Q
217.0
13.3
16.0
13.3
IA.Q
18.2
22,5
16,3
17,0
19,0
17,5
2J.S
12,3
13.0
9.3
IX©
8.3
7,3
14, S
14.3
18, S
13. Q
13.3
11.5
13.8
8,4
14.3
§.@
9.5
12. §
16.9
13.3
11.0
12.7
12.8
11.3
14,4
10.9
11.3
11.8
12.4
 Total  in primary affluent .

B
 Dissolved in primary affluent.
Total in secondary effluent.


Dissolved in oscondory effluent<

-------
     Table  15 (continued),   STEADY-STATE NITROGEN AND
                PHOSPHORUS CONCEOTuATIONS
Orehophosphate»
   mg/1 as P
 B       D
 Mixed lic-jor
    total
   nitrogea
Dg/1 as NST
 Mixed liquor
     total
   phosphorus,
ag/1  as Pf~
9.0 15.5
10.0 12.0
17.0 11.0
16.0 12.5
12.0 11.5
-
11.8 9.4
-
_ _
-
-
-
-
-
-
-
- •
12. 1 7.6
-
9.4 6.9
-
-
»
-
«.
-
-
-
-
-
10, 1 S.6
-
9.1 9.1
-•
-
364
309
276
248
430
372
374
362
273
247
271
311
267
276
280
255
284
237
276
258
264
248
283
249
241
277
220
241
246
243
244
276
215
246
233
10.6
10.4
9.0
7.3
10.0
10.7
10.4
10.8
12.0
11.5
12.4
12.3
12.0
11.4
11.6
11.4
U.I
9.7
10.8
9.4
9.3
10.1
11.2
10.7
12.6
12.6
12.2
13.3
16.0
13.0
14.1
14.2
12.3
12.7
12.7
54.5
18.0
67.5
81.0
120
102
161
144
165
80.2
186
107
70.0
101
88.7
95.5
105
99.2
128
90.2
56.2
61.0
101
101 .
53.2
122
69.7
36.1
40.5
74.5
51.0
71.5
130
101
71.2
i.e
0.61
2.2
2.C
2.E
2.9
4.4
4.3
7.5
3.7
8.5
4.2
3.2
4.2
3.7
4.3
4.1
4.1
5.0
3.3
2.0
2.5
4.0
4.3
2.8
5.6
3.9
1.0
2.6
4.2
2.9
3.7
7.4
5.2
3.4_
                             99

-------
Table 15 (continued),,  STMDY-SE&TB MISS0GHH MB
          PHOSPHOKUS COBSCPWS&SIONS
Kjcldohl AcnijaiaD aitsite,,
aittfOKQn. as/ 1 ao H
Bato
SSsj>71
6Sap71
9Ssp71
IS. Sop 71
13S3p71
13Sap71
14§@p71
IS Sap 71
17Sop71
lSSap71
20Sap71
28Sag>7!
2iSap71
10ee71
30c£71
40ce71
30ct71
60ce71
7Cce71
S0ce71
X00ce71
Il0ce7l
9Hov7i
10Hov71
14Rov71
23Hov71
24KoWl
258&W71
26Kov71
29Ko^71
Uaa72
2Joa72
SJosa72
SJon72
SJoa72
16Joa72
12Joia72
*»««.
\oeol
A
33.1
31.8
33.7
33.1
36.2
32.4
31.1
32.4
42.6
29.2
30.3
36.9
36.3
61.1
36.3
33.6
35.6
36.3
39.3
36.3
33.7
36.3
44.1
41.4
43.0
39.7
38.1
43.0
44.4
37.7
42.3
43.3
39.9
46.6
41.1
41.7
49.0
33.8
in guric
B
25.4
.30.5
30.3
29.2
•29.2
23.6
28.6
28.6
38.8
26.7
29.9
33.1
24.4
41.1
33^7
32.5
32.3
33.7
3^.4
31.2
30.5
31.8
39.2
38.1
35.3
35.9
33.6
39.2
37.7
34.1
33.1
34.3
33.7
40.3
33.3
41.7
47.8
33.3
C
23.5
27.3
22.2
25.4
24.3
27.2
22.9
25.4
26.7
21.6
27.3
29.2
31.2
31.8
24.2
26.7
26.1
27.4
26.7
31.8
24.8
23.5
35.9
31.4
31.6
30.9
31.4
32.5
35.9
31.7
31.4
33.3
36.3
36.9
32.7
38.1
38.7
29.9
9
21.6
24.8
21.0
22.2
20.3
24.2
21.6
23.5
25.4
21.6
24.2
24. 8
28.0
30.5
24.2
21.6
25.3
27.4
26.7
26.7
22.9
24.8
33.1
28.1
28.1
28.1
27.0
28.1
33.5
29.8
26.0
29.0
29.6
31.4
29.6
32.1
36.9
27.9
airy G?21uene.
Mooolvod in prieJK
y sfOuenfc.
os/1 ao B ea/1
A
20.3
=
•>
~
19.4
-
-
19.4
-
16.1
=
24.8
-
c,
22.6
-
-
=
23.9
0 .
22.3
-
—
-
24.8
=
=
25.1
-
0
_
23.0
_
23.1
.
. =
-
23.0
C
16.3

-
-
16.8
-
-
16.3
-
13.9
-
21.0
-
„
19.7
-
_
=
19.4
-
17.5
-
—
_
21.0
_
-
20.4
-
-
_
19.1
=
20.6
_
-
-
20,9
CToeol in
9 B
15.9 0.03
_
= 0.02
= . =
17.2 0.3S
_
*.
18.4 0.31
= =
16.3 0.21
«
21.0 0.00
= =
_ <=
19.7 0.22
.
o = '
0 = .
19,1 0.32
= »
16.2 0.66
_
^ «»
_ =
21.0 0.00
= =
=
20.4 0.00
_ =
= =,
• - =
19.1 0.09
- =
20.3 0.00
• <. =
= =
«,
20.9 0.08
oecoadosy o
. as M
9
0.79
'-
1.41
-
l.GO
=
o
0.27
•=•
1.22
- •
-
-
„
1,44
-
=
=
2.76
=
4.23
-
.—
-
0.63
=
=
1.32 •
-
_
=
0.83
-
0.48
<=.
=
=
@.90
Q2 lu3EB£.
to£a£ pboophaee,,
£20/1 QB.P
A
13.3
21.0
23.2
17.8
15.8
13.3
13.8
12.0
16.8
18.3
16.8
11.3
26.5
23.0
13.3
IS. 3
18.3
13.0
14.0
16.3
16.3
17.3
17.3
17.3
22.4
13.3
11.2
16.3
13.3
13.3
14.3
13.3
7.1
9.7
W.4
17.3
11.2
17,8

u
14.3
18.3
21.0
17.3
13.8
13.8-
14.8
9.0
13.3
18.3
16. §
10.5
18.3
i3.a
12.3
14.3
13.0
13.0
14.0
. 14.®
12.8
13.3
14.3
14.3
20.4
12.2
11.2
14.3
12.2
14.3
11. 2
9.2
7.1
6.3
13,3
10.2
ll.2
14.0

C 9
3.4 6.8
17.8 14.4
25.2 13.4
17,8 14.7
13.8 11.3
16.3 16.0
13.3 13.1
11.5 10.8
12.0 9.S
14.3 9.4
11.3 O.O
13.5 11.3
23.3 16.8
11.5 11.5
11.3 10.8
14.3 12.3
11.0 11.0
9.0 9.5
9.0 8.5
11.5 11.0
12.3 13.8
12.3 12.8
12.8 11.5
13.0 13.0
11.3 11.3
13.5 13.3
13.3 12.3
.14.8 11.8
12.8 13.3
13.8 13.8-
9.7 9.2
Aio2 JiAoW
8.3 f>.2
8.2 7.4
12.2 11.7
12.2 11.8
13.8 7.6
14.7 12.9

B ''
Biooolved in oocCTitoiry oSfflKaae.
                100

-------
Table 15 (continued).   STEADY-STATE NITROGEN AND
          PHOSPHORUS CONCENTRATIONS
Mixed liquor
Orthophosphate, total
mg/1 as P nitrogen.
B
12.5
—
11.8
_
12.5
_
_
9.4
_
10.8
-
_
-
—
13.0
-
-
-
10.8
-
13.8
—
_
-
8.9
-
-
7.4
-
-
-
13.3
-
7.9

-
-
D mg/1 as
9.1 238
228
9.1 294
232
7.6 184
189
211
9.1 216
283
9.6 " 217
245
136
146
190
9.1 134
124
131
146
8.4 134
149
11.0 132
116
333
334
9.2 an
240
240
8.9 275
233
- • §08
130
10.7 119
123
5.9 131
123
122
149
N Z
-1.8
12.7
17.7
15.8
12.0
14.0
13.1
12.7
16.7
11.9
13.2
14.8
12.3
15.1
13.3
12.2
13.3
13.6
13.6
17.7
12.5
12.3
10.2
13.2
10.7
11.6
. 12.6
11.6
11.3
11.7
10.9
11.5
12.9
11.8
11.7
12.7
10.8
Mixed liquor
total
phosphorus.
mg/1 as 1
45.7
70.2
89.5
81.5
108
43.0
45.5
53.5
49.6
62.3
61.8
30.0
32.6
79.5
47.0
50.2
31.3
37.0
42.2
28.0
41.7
28.7
66.4
39.2
37.2
58.9
63.4
34.1
31.0
42.8
35.8
33.6
22.0
36.8
37.7
35.2
36.8
> ;.
2.3
3.9
5.4
5.5
7.0
3.2
2.8
3.2
2.9
3.4
3.3
2.S
2.7
<§.3
4.6
4.9
3.2
3.4
3.7
3.3
4.0
3.0
2.0
1.6
2.3
2.8
3.3
2.6
2:3
2.4
3.0
3.1
2.3
2.9
3.5
3.7
2.5
   11.3      9.62          12.2              3.6
                      101

-------
             Table 16.  AVERAGE NITROGEN AND PHOSPHORUS CONCENTRATIONS IN PRIMARY AND SECONDARY EFFLUENTS
o
N>
Nutrient
• * . \.t
Nitrogen
Total Kjeldahl nitrogen
Dissolved Kjeldahl nitrogen
Total ammonia nitrogen
Dissolved ammonia nitrogen
Dissolved nitrate and nitrite nitrogen
Total dissolved nitrogen
Total nitrogen
Phosphorus
Dissolved orthophosphate
Total dissolved phosphate
Total nhosrahafta
Primary effluent
Concentration^
mg/1 as N

38.8
33.5
23.0
- •
0.08
33.58
38.88

11.3
14.8
17.8
Percent,
%.

99.8
86.2
59.2
- . '
0.2
86.4
100.

63.5
83.2
100
Secondary
effluent
Concentrationp Percent,
mg/1 as P %

29.9
27.9
20.9
20.9
0.90
28.80
30.8

9.62
12.9
14.7

97.1
90.6
. 67.9
67.9
2.9
93.5
100

65.4 .
87.7
100

-------
     Nitrogen removal by the activated sludge process is accomplished by
the synthesis of nitrogen in the activated sludge and possibly by deni-
trification.  It is assumed that both the dissolved and particulate nitro-
genous forms in the primary effluent are available for biosynthesis.
Because most solids in the secondary effluent are biological cells, excess
nutrients are assumed to be present only in soluble forms.
    Table 17 presents the nitrogen removal efficiencies and removal vel-
ocities of various nitrogen species.  Removal efficiencies for the various
nitrogen species were relatively constant when the system was operated
at high rates.  However, the removal efficiencies varied widely when the
system was operated at low rates, i.e., 1/6C » 0,036 to 0.071 day"  .
Approximately 27 percent of the total Kjeldahl nitrogen and 22 percent
of the dissolved Kjeldahl nitrogen was removed by activated sludge.,
Based on grab sample measurements during a three-day period, only 8,2
percent of the ammonia present was incorporated into cell material.  It
appears that the nitrogen supply in the primary effluent was in gross     '
excess of that required for activated sludge growth| hence, nitrogen was
not the limiting nutrient in this study.
    The net yield coefficient with respect to specific nutrient can be
defined as the net amount of cells produced per unit amount of nutrient
removed s, or

                               ,    ,    FX_ + F  (X  - X0)
                  _  cells produced  =   2    wv r    2'             (   }
                n   nutrient removed       F(SQ - S^

                                    VX
 here                    6   °  py       , - rr^-                      (18)
                         c    FX2 "*" Fw(Xr  ~   2*
                                 F(SQ  -  S}
                             
-------
Table 17 „  KUMIEM 1S2QWAL VELOCITIES AS©
Dote
17Bac70
18Bac70
19 Da c 70
20Dac70
21Bsc70
31Bsc70
2Jon71
3Jon71
5Jan71
15Jan71
16Jan71
17Jaa71
18Jan7i
15Ap?71
16Apr71
18Apr71
19Apir71
9May71
llMay71
12May71
13May71
14May71
16May71
17Kay71
18ftey71
19Kay7i
20Hay71
2 Way 71
23May71
24May71
25May71
28Msy71
29Msy71
16Aug71
17Aus71
20Au871
-23Aug71
24Aug71
25Aug71
26Aug71
28Aug71
29Aup/l
30Aus71
31Aug71

' Yoeal B
KJaldehi
0°
0°.0024
6.0110
0.6086
0.0190
=0.0007
0.6064
0.0150
0.0225
0.0364
0..0286
0.
0.0. 8$
0.0240
=©.©220
0.0336
0.0559
0.@629
=0. 125
0.124
0.0712
0.0531
0.0490
0.071S
O.OS52
0.0617
0.0911
0.0753
0.0472
0.0612
0.0998
0.0741
0.202
0.134
0.162
0.157
0.180
0.218
0.222
0.195.
-OJB087
0.0933
0.253
Hue rfLi
lioBolvsd
Kjeldahi

c,
-
=
-
«-•
-
0
=
=
=
=
=
-
-
-
-
-
0
-
-
=
-
-
=
•>
—
0.129
0.0921
0.0305
©.141
0.124
0.166
0.131
"
=0.0247
0.0315
©. 10&
sat soeovol
sss..
=0.0141
=0.0114
=0.0032
0.
-0.0047
0.0023
0.0025
=0.0007
0.0060
0.0101
-0.0070
0.0155
0.0062
0.0012
-
0.004®
-
0.0112
-
-
0.0343
~
0.0081
—
—
-
0.0100
-
0.0148
-
-
-
-
-
-
-
-
-
-
0.0705
-
0.0775
-
-
{q3
vole ty, (QB
Toeal
phosphate
0.0063
0.0048
0.0046
0.0295
0.0092
0.0183
0.0023
=0.0042
=0.0067
0.0049
0.0196
0.0084
0.0027
0.0183
0.0222
0.0123
O.GO&O
0.0302
0.0058
do® £03
0.0483
0.0243
0.0124
0.0431
0.0433
0.0476
0.0330
0.0624
0.023Q
0.0230
0.0524
0.0623
0.0963
0.0760
0.0369
0.0415
0.0566
0.173
0.0662
0.116
6.0906
0.103
0.104
K or P pocsrc
> MLVSS) (dCR?I
Total
dlosolved
phosphate
-
-
-
-
-
-
-
_
-
•
"
'
-
-
•
-
<*
- .
_
-
- -
-
=
-
-
-.
"
0.0660
0.0761
0.0105
0.0362
0.0439
0.162
O.OS63
0.0952
0.106
0.1036
0.1036
;a«35)
i
,=£-
I
=
=
=0.0110
=0.0039
©002.12
®.0®5S
O.QOli
=
©<,6@&6
=
=
-
. =
="
=
=
=
c.
=
O.Q252
•>
@.OH26
=
"
•*
• —
=
=
=
=
=
o
©.§21$
0
• o.
=
=
                                 104

-------
Table 17 (continued).  NUTRIENT REMOVAL VELOCITIES
              AND REMOVAL EFFICIENCIES

Nutrient
Total Dissolved
Kjeldahl Kjeldahl
nitrogen nitrogen
-26
0
-7.5
4.2
2
14
22
-1.3
9.5
26
28
37
35
0
22
23
23
29
26
28
47
45
28
26
23
30
2V
27
37
36
24
28
39
32
40
33
33
32
33
40
42
36
2.4
22
41
-
-
v
-
-
-
.
_
-
_
-
-
-
.
-
-
- •
-
--
-
_
«•
<*
~
-
"
°
=
-
30
26
20
30
26
34
32
-
i.4
8.6
22
removal efficiency, Z
Ammonia
nitrogen
-6.0
-32
-25
-9.5
0
15
4.7
5.4
-1.7
14
21
-18
32
17
2.5

7.2
-
9.9
-
-
28
-
6.2
-
-
«=>
7.7
«,
13
.=
.= '
«,
-
=
=
=
-
=
=
21
=
24
=
-
Total Dissolved
Total dissolved ortho-
phosphate phosphate phosphate
12
19
15
58
20
43
7.5
-18
-22
13
38
21
- 6.9
33
40
25
9.7
26
52
70
35
24
10
36
J/
42
31
60
26
34
49
44
30
34
20
20
22
52
24
44
35
41
38
-
-
-
-
-
-
-
-
-
-
-
-
-
.
-
•
-
-
-
-
-
—
-
-
=
-
-
-
-
23
34
6.8
18
19
50
24
39
33
41
38
-
-
-
-
-
-72
-20
35
22
4.2
-
20
-
-
-
-
-
-
-
-
«*
—
37
-
27
-
—
—
—
-
-
-
-
-
-
15
-
0.
-
-
                          105

-------
Table 17 (continued) „  MJTRIMT REMOVAL
              AKD RMOVAL EFFICIMCIES
Dots
5Sap71
6Sep71
9Ssp71
HSep71
12Sap71
12Sep71
14Sep71
16Sep?l
17Sep71
19Sep71
20Sep71
28Sep71
29Sep71
10ct71
3Oct71
40ct71
50ct71
60ct71
70ct71
90ct71
100ct71
H0ct71
9Nov71
10Wov71
14Nov71
23Mov71
2«Nov71
25Mov71
26Mov71
29Hov71
!Jcn72
2Jon72

Total
KjaWehl
0.144
0.0921
0.18?
0.188
0.232
0.149
0.145
0.131
0.234
0.104
0.0831
0.288
0.5L63
O.S23
0.286
0.342.
0.240
0.199
0.268
0.276
0.244
0.290
O.OS61
0.106
0.148
0.131
0.139
0.147
0.126
0.106
0.346
0.348
RuStrieat SSEOVO! •
DiooolvsS
KjeidaJjl Aeasaia
fflitroBea sigffogsn
0.0473 0.0549
0.0732
0. 141
0.121
0.142 0.0349
O.§300
0. 107
0.0730 0.0146
0. 199
0.0699 0.0281
0.0752
0. 1®§
0.123
0.211 - ' .
0.224 0.0684
0.26®
0. 167
0. 141
0.161 0.100
0.129
0.172 0.138
0.177
0.0478
0.07%
0.0716 0.0377
0.0394
O.OQ2Q
o. aao
0.04S3
0.0377
0.194 • -
0.132 0.0933
ifrw

Total
0.106
0.0869
0.175
0.0533
0.0713
=0.0127
0.0412
0.0176
0.103
0.122
0.076S
0.
0.203
0.230
0.106
0.146
0.174
0.123
0.115
0.152
0.0566
0.114
0.0434
0.0341
0.110
0.
-0.0138.
0.0444
0.
15). 020 1
0.108
0.0839
j N or P trecB^
Jan I3.VSS) Was?
Total
diooolvsd
0.0939
0.0314
0.1129
0.0448
0.0397
=0.0400
0.0260
-0.0264
0.0563
0.122
0.0766
=0.0190
0.0317
0.0461
0.0334
0.0437
0.0945
0.123
0.113
0.0@S2
-0.0226
0.0126
0.0219
0.0103
0.0906
-0.0124
-0.0130
0.0247
-0.0127
0.0067
0.0423
°0.0623
3«a>
)
Pto5£o
©.©423
<=
Oo®4@i
=
@.©770
=
=
0.0344

©.©iSS •
o
0
=
=
§o@f21
0. .
ca
a
0.0S03
= •
OoG^^i4
=
0
=
-a.ooss
=
c,
-*@o016f
=
=
=
@.©S2S
                           106

-------
Table 17 (continued).   NUTRIENT REMOVAL VELOCITIES
              AND REMOVAL EFFICIENCIES.

Total
Kjeldahl
nitrogen
35
22
38
33
44
25
30
27
40
26
21
33
21
50
33
39
28
24
32
26
32
32
25
32
35
29
29
35
24
21
38
33
Nutrient
Dissolved
Kjeldahl
nitrogen
15
19
31
24
30
15
2*
18
34
19
19
25
17
26
28
33
22
19
22
14
25
22
16
26
20
22
20
28
11
13
26
16
removal efficiency, %
Ammonia
nitrogen
22
-
-
-
11
-
<=•
5.1
«,
8.8
0
„
~
_
13
_
-
-
20
-
27
-
~
-
15
-
-
19
-
-
»
17
Total
• phosphate
56
31
47
17
28
-4.6
17
10
43
49
34
0
37
50
39
33
40
37
39
32
15
26
34
25
50
0
-9.8
28
0
8.8
36
23
Total
dissolved
phosphate
52
21
36
15
18
-16
11
-20
2o
49
34
-7.6
8.2
17
12
14
27
37
39
21
-7.8
3.8
20
9.1
45
-9.0
-9.8
17
-9.0
3.5
18
-28
Dissolved
ortho-
phosphate
27
'
23
-
39
_ .
=
3.2
.
11
_
_
-
_
30
„
• „
«
22
_
20
-
—
.
3.4
_
a
-20
.
-
-
20
                             107

-------
Based on these net growth expressionsp the net yield coe£ficisnts oL
various nitrogen species were  computed to be as follows;

                 v   _ii*       pan MLVSS produced)      .      '  •
                            (mg KJeldshl. nitrogen removed)
                       20  i  ,_	(mg MLVSS produced)
                            '    total ammonia nitsogen removed)
Because no nitro§©a  eaaiyses  were  made  directly  on  the  cells0 the nitrogen-
content in the  activated sludge was  estimated  from  the  difference between .
total particulate  aad dissolved nitrogen concentrations determined on  the
mixed liquoro   The calculated total  nitrogen concentrations  in  the activa-
ted sludge are  listed in Table 15„  The concentrations  varied between  7=3
and 16.8 percents  with an average  of 12.2 percent.   This  average nitrogen
content of activated sludge corresponds to a nitrogen yield  coefficient  of
8021  (mg BiLVSS  produced)/(mg  total nitrogen removed) 0  These yield values
and nitrogen  content appear to be  realistic estimates of  the nitrogen  con-
version and are within the range of  reported values which vary  from  5<>6
to  1204 percent (References 280 420  43  and 44) „
Phosphorus
    Daily steady-state total  phosphate  and total dissolved phosphate
•measurements  were  made on the primary, and secondary effluents,,  Dissolved
orthophosphate  Has determined on  three-day grab  samples of the  primary
and secondary effluents,,  These results are presented in Table  3,50   Total
phosphate expressed  a& P ia the primary effluent varied from 701  to  26 05
with  an average of 1708 mg/1  as P  and the total  dissolved phosphate
ranged from 70i to 23„ with an average  of 14 „ 8 mg/!0  On the other hand0
the total dissolved  phosphate in  the secondary effluent varied  from  6»8
to  2205D with an average of 1209 mg/l0  and the' total phosphate  varied
from  802 to 36»50  with an average  of 14„7 mg/1 as P0  From thrse=day grab
sample analysesD dissolved orthophosphate expressed as  P varied from 704
to  UoOp with an average of 1103 mg/lj,  in the primary effluentg and  509
to  15050 with an average of 9062 mg/1,,  in the secondary effluent0

                                     108

-------
    Table 17 also presents the phosphate removal efficiencies and remov-
al velocities which were calculated based on the assumptions that both
the particulate and dissolved phosphate in the primary effluent are
available for biosynthesis and excess phosphates are present in the
soluble forms in the secondary effluent.  Approximately 27.8 percent of
total phosphate or 16.1 percent of total dissolved phosphate was removed
by activated sludge.  Based on three-day grab sample analyses, 12 percent
of dissolved orthophosphate was incorporated into cell material.  It
appears that phosphorus supply in the primary effluent was in gross
excess of the phosphorus required for cellular growth; hence phosphorus
was not the limiting nutrient in this study.
    The net yield coefficients (Equation 40) based oh phosphorus were
found to be as follows:
        _,    ...	(mg MLVSS produced)
        I         	—	
         n     *  (mg total dissolved phosphate as P removed)

        Y  = 28 r	(mg MLVSS produced)	
         n        (mg dissolved orthophosphate as P removed)

Since no phosphorus analyses  were made on  activated sludge,,  the  phosphorus
content in the activated sludge was  estimated from the  difference  between
total particulate and dissolved phosphorus concentration made  on the  mixed
liquor„  The estimated  phosphorus contents in the activated sludge varied
from 0061 to 7039 percent with an average  of 3o60 percent (Table 15)»
This average phosphorus content of  activated sludge corresponds  to a  phos-
phorus yield coefficient of 2708  (mg MLVSS produced)/(mg phosphorus removed)
    Reported values of  phosphorus content  in activated  sludge  range from
2  to 3 percent  (Reference 25)„  The slightly high phosphorus content  of
cells noted in  this study may have  been  caused by greater phosphate up-
take rate and greater phosphorus  storage„   Excess phosphate uptake was
observed by Toerien et  al<, (Reference 7) in an algal growth  kinetic study
under phosphorus  limitation using Selenastrtsa capricoxnutum as a tes£
organism,,

                                   109

-------
    In the treatueat of several nutrient°d«i'ici@nt industrial wastes „
Helmers et &10  (Sfflference  45)  determined rainteal qusratiti®® of nitrogen
and phosphorus  of 40 (mg M)/(§.BOD  reeoved)  and 6
This is approximately  equivalent  to a BOD'sNsP  ratio of  150§5s:
the BODsHsP ratio %?®s  150s48s22 in  the  primary effluent„ it is obvious
that neither nitrogen  nor  phosphorus was a limiting nutrient  la  this
process o  Although  in  the  absence of typical values of  half-=s©turatiom
constants of nitrogen  and  phosphorus (K M  and  K _) „ it  is  conceivable
                                        S ™      o&
that the nitrogen and  phosphorus  concentrations in the  aeration
effluent  (S-.,  or S.J)  were, much greater than the K    or K    values; that
           JLw     JLtt                              8K      SJr
is, S.M » K ... and  S.- »  K Bo Thus,  the  nitrogen aad  phosphorus  reraoval
     IN     SK      Li?     8"
velocities  (q., or qn)  were zero-order  with respect to S,M  or  S.^o   Conse-
             fj     f                                   J.W      JL*
quentlys  the Michaelis=-Menten (Monod)  model (Equation 3)  for  ffiitsogen  or
phosphorus as  a limiting nutrient is not  applicable.   Furthermore0 since
other macronutrients and raicr©nutrients are usually  present in sufficient
quantity  in domestic sewage9 the  organic  substrate measured as BOD or  C00
appeared  to be the  sole growth limiting factor in this  study,

SOLIDS  SEPARATION

    The activated sludge process  incorporates  soluble and particulate
materials into a mass  of biological solids which must be separated fro&
the process effluent.   Sludge settling and compacting characteristics  ar@
a primary requisite to successful operation of the activated sludge pro=
cesso   One of  the objectives of this study was the evaluation of selects^
alternative solids  separation systems„  The selected systems iacludsd
vibratory screening,, enhanced gravity sedimentation„ dissolved air flot®=
tion and  pressurised 'hydro-centrifugal screening,,
Sludge  Settling Characteristics
     Several sludge characteristics are of importance in determining
 settleability0   These sludge characteristics are particle siss distribution
 particle shape D  particle density„ particle surface charge asud sludge voiusas
 index,,   The project was too limited to continuously monitor all of
                                    110

-------
sludge characteristics and correlate them with sludge settleability and
activated sludge operating parameters.  However, some qualitative analy-
ses can be summarized.
    Sludge volume index measurements were made on mixed liquor under
presumed steady-state conditions and are presented in Table 14.  Sludge
volume index varied from 25 at an organic loading rate of 2.00 (mg BOD)/
(rag MLVSS)(day) to 935 at an organic loading rate of 1.94 (mg BOD)/
(mg MLVSS)(day).  Figure 20 shows the variations of sludge volume index
with BOD loading and COD loading rates.  No apparent relationships can
be developed from these widely scattered data.
    It was observed that at low organic loading rate, e.g., less than
1.0 (mg BOD)/(mg MLVSS)(day) or 3.0  (mg COD)/(mg MLVSS)(day)8 the col-
loidal materials in the primary effluent were effectively flocculated
by activated sludge.  At higher organic loadings, the flocculating capac-
ity of the activated sludge apparently was insufficient to flocculate all
colloidal particles causing a very turbid secondary effluent.
    Qualitative morphological microscopic examinations revealed that the
percentage of  filamentous organisms  present in activated sludge increased
with  increased sludge volume index;  also increases in organic loading
tended to stimulate the growth of filamentous organisms„
Vibratory Screening
    A set of SWECO vibrating screens, equipped with three interchangeable
screen materials, was incorporated into the facility.  The three screens
supplied with  the units included 0.044- and 0.037-mm opening  (325- and
400-mesh) stainless steel plain weave screens„ and a 0.014- by 0.105-tiuu
opening  (720-  by  140-mesh) dutch twilled stainless ste*. I screen.,  Each
screen was equipped with  a fine spray washing system for removal of
trapped materials.
    The  screens were  tested  under varying operating conditions which
included  screen size  opening, speed  of  vibratory motor, solids and hy-
draulic  loading rates  and the angle  between  top and bottom vibratory
                                   111

-------
1
                1     of
                       o
                        o
                     o
                      o
                 ©  o
                                    0©
                                                             7     •  S
11     13

-------
weights.  Table  18  presents  the screen performance characteristics and
operating conditions.  Average values  of solids removal efficiencies and
filtration rates are summarized  in Table 19.  The  speed of the vibratory
motor, in the narrow range of 1,100 to 1,500 rpm,  and the angle between
vibratory weights were not found to have a significant effect on per-
formance and were discounted from further consideration.
    Average solids  removal efficiencies from the effluent stream with  the
0.044- and 0.037-mm opening  (325- and  400-mesh) screens were 38 and 49
                                                       3   2
percent, at average filtration  rates of 16.6 and  16.0 m /(m )(day)
                    2
 [408 and 393 gal/(ft )(day)]» respectively, which  are considered  to be un-
acceptable performance.   Suspended solids recovery with these screens  was
too low to return sufficient solids to the aeration tank.  Average solids
removal efficiencies with the 0.014- by 0.105-ram  opening  (720- by  140-mesh)
screen  averaged  91  percent (a value approaching the performance of gravity
                                                  32
settlers) at an  average  filtration rate of 2.98 m /(m )(day)  [73.2 gal/
 (ft2)(day)].
    Hydraulic  capacities of  the vibratory screens  are presented  in Figures
 21, 22  and 23.   Normalized filtration  ratesD which are  the  ratio  of fil-
 tration rate to  hydraulic loading  rates were plotted against  the  corres-
 ponding solids loading rates for each  screen size0  The hydraulic capac-
 ity of  the 0.044-mm opening  (325-mesh) screen  depicted  in Figure  21 ap-
 pears  to be nearly  independent  of  solids  loading  rate.
    Normalized filtration rates of the 0.037-mm opening (400-mesh) screen
 generally  decreases as solids  loading  rates  increased,,  as shown  in Figure
 22o   Results were  erratic, but  this  smaller mesh  size was apparently more
 susceptible  to hydraulic head losses  caused by suspended  solids  and hy-
 draulic loading than the 00044-mm  opening  (325-mesh) screen.
    Whereas  the  solids removal  efficiency of  the  0,014- by  Ool05-mm open-
 ing (720-  by  140-mesh) screen was  acceptable,,  the filtration rate was
 far from acceptable at the  suspended solids  concentrations  applied.  At
                                                2        '            2
 solids loading rates on the  order  of 97.9 kg/(m)(day)  [20,0 lb/(ft )(day)]s
 generally  less than 10 percent  of  the applied  hydraulic flow passed through
 the filters,  as shown in Figure 23.
                                   113

-------
Table 18.
Solids
T.:st loading sate,,
HiBBber kg/ (s^) (day)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
34.2
24.7
33.0
20.5
28.4
14.8
17.5
117
132
89.7
108
79.8
30.2
59.7
30.2
71.3
50.2
111
93.
76.
50. 
-------
Table 18 (continued).  VIBRATORY SCREEN PERFORMANCE DATA
S.Uids
Test loading rate,
Number kg/ (m2) (day)
46
47
48
49
SO
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
193
206
52.6
55.0
105
109
114
106
76.2
88.8
76.8
81.4
53.9
53.5
88.0
51.0
98.2
70.4
104
58.6
92.4
61.7
97.2
76.1
121
30.2
25.0
19.0
104
120
131
115
98.2
118
62.8
37.9
36.6
93.0
81.3
103
67.5
86.4
93.0
101
Filtration
Filtration rate/
rate, hydraulic
m/(m) (day) loading ratio
39.9
55.4
13.0
13.7
23.6
23.9
25.8
24.2
18.1
19.7
17.6
21.0
14.4
14.0
20.5
12.3
24.4
16.4
25.8
16.0
26.2
13.4
26.3
15.8
27.9
8.06
5.70
7.77
27.0
10.6
17.1
28.7
10.6
28.4
7.98
9.73
2.03
1.42
0.24
3.79
0.41
2.24
0.98
0.81
0.73
0.95
0.85
0.85
0.91
0.88
0.92
0.93
0.97
0.90
0.90
0.96
0.94
0.96
0.86
0.91
0.94
0.91
0.93
0.90
0.94
0.65
0.94
0.84
0.94
0.59
0.68
0.86
0.75
0.29
0.45
0.86
0.37
0.72
0.36
0.88
0.23
0.06
0.01
0.13
0.02
0.09
0.04
0.03
Solids
Influent Effluent removal Screen
suspended suspended ef f tciency, o^erJ ng,
eolids, mg/1 solids, ag/1 X j
3540
3540
3440
3440
4050
4050
4050
4070
4070
4070
3930
3730
3530
3680
3680
3780
3780
3720
3720
3320
3520
3490
3490
4070
4070
2230
3000
2100
2880
3340
3460
3450
3500
3010
2880
2440
4050
4070
3930
3730
3780
!3780
4070
4070
2420
2920
2480
1680
3500
2770
3110
3200
3170
2830
2550
3100
2990
1790
2620
2440
2550
2350
2140
2160
2100
2150
2660
2760
3100
860
83d
1040
1180
1640
1840
1950
2030
232C
1400
330
300
180
130
160
90
100
168
130
31.6
17.5
27.9
51.2
13.6
31.6
23.2
21.2
22.1
30.5
35.1
17.0
15.3
51.4
28.8
35.5
32.5
36.9
32.7
38.1
40.5
38.4
23.7
32.1
23.8
61.4
72.3
50.2
59.0
50.7
46.6
43.5
42.0
22.8
51.6
90.4
92.6
95.6
96.7
95.7
97.6
97.4
95.9
96.8
44
44
44
-44
44
44
44
44
44
44
44
44
44
44
44
44
44
44
44
44
44
44
44
44
44
37
37
37
37
37
37
37
37
37
14 x 105
14 x 105
14 a 105
14 a 105
14 a 105
14 a 105
14 a 105
14 n 105
14 a 105
14 a 105
                              115

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Table 19.  SUMMARY OF VIBRATORY SCREEN PERFORMANCE
Screen
Mesh Opening ,
Number u
325 44
400 37
20 x 140 14 x 105
Average
influent
solids
concentration „
mg/1
3,395
2,997
3,780
Average
solids removal
efficiency,
38.0
49.0.
91.0
Average
filtration
ratep
m3/(m2)(day)
17.3
16.0
2.97

-------
     100
Eft
     70
X
     10
••'. °J«, ."* ' ..'.'* /-'v. • -l ' '
— oo 9° * .
0 «••••.
— . ° • . • , •
__ o
— »
1 1 1 1 1 II 1
1 20 40 SO 60 100 120 140 160
1 1 .
^^mm

—
	
	
1 1
160 200
                              SOLIDS LOADING RATE, kg/(m2) (day)
               gure  21   Hydrau! ie  capacity of  vibratory 0%
                                    (325-fnesh)  screen
opening

-------
                                  !        I
1    ~~T
09
            t/VJ)
            •
            1UJ1
                                                                '© 3348
                                                                        m
                                                         sh)  scree

-------
100

 90

 80

 70

 60

 50

 40

 30

 20

 10
1
         3440
       • 4050
I
2880



               © 3730

• 3780 L 393Q9  4°9 °4070
                                                            I
                                                          T
                                                         T
                                                          NUMBERS REFER TO
                                                          INFLUENT SUSPENDED
                                                          SOLIDS CONCENTRATION
          20
        40
        80
                            SOL IOS

   Figure 23   Hydraulic capacity
    100      120     140
    RATE.  kg/(m2)  (day)

of. vibratory 0.014-1
f  140-fliesh)  screen
                                              180
200

-------
    Because the attainment of relatively high filtration rates could raot
be achieved with the type of vibratory screening provided for 'this study0
the testing of the vibratory screens was discontinued in-favor of an«=.
hanced gravity ssdiwsntatiosu
Enhanced Gravity Separation
                 i
    During the studies of the accelerated high-rate activated sludge
system^ suspended solids removal from the mixed liquor Has accomplished
by two circularD 1608»ra (55-ft) diameter gravity settlers,  Both settlers
were operated in-parallel during each steady-state period and their per=
formance Has determined from analyses drawn from a common effluent sump
and a common return solids sump.  Table 20 summarizes average operating
parameters and performance characteristics of .the gravity settlers dur-
ing the steady-state activated sludge process operations0  .
    The effect of hydraulic SUE face  loading rate on gravity settler per-
formance is shown in Figure 24„  The hydraulic surface loading rate var-
ied between 5,0 and 13,3 m3/(m2)(day)  [123 and 327 gal/(ft2)(day)] in
the tests at Chino*  These surface loading rates are much lower  than
                                      32                   2
those usually used,, i0e0£, about  32,6 m  /(m )(day)  [800 gal/(ft ) (day) ]
for conventional activated sludge processes,  With the exception of the
single high value point„ effluent suspended solids appeared to be  little
affected by.hydraulic  surface  loading rates in the range studied,,  Al-
though return sludge solids concentrations generally decreased with in-
creasing hydraulic  surface loading  rates„  the large variations of  con-
centrations encountered  in the extremely narrow  range  of surface loading
rates between  12..2  and 13,4 m3/(m2)(day)  [300 and  330  gal/(ft2)(day)]
indicate the  influence of a  factor  other  than surface  loading rate,
    The effect of mean cell age  on  gravity settler performance is  shown
                   V. v                             .               .
in Figure  25„  Return  solids  concentration  from  the  gravity settlers
indicated  a marked  increase with increasing mean cell  age.  The  five
widely spread  return solids  concent rations.„  indicated  in Figure  ?4 in
                                                         '32,
the narrow range of hydraulic  Loading  ratesp  12.3  and  13.4 nt  /(m )(dayj
                    2
 [300  and  330  gal/(f6  )(day)]„  achieve  greater significance  in their
apparently closer  relationship to mean  cell  age.   Effluent  uuspended

                                 120

-------
Table 20.  GRAVITY SETTLER PERFORMANCE
Steady-
state
run
1
et
3
4
5
6
7
8
9
-•irface
-'.cacine rai:es
nrV(m~)(day)
.9.89
12.3
5.01
7.20
7.45
13.1
13.0
13.3
12.6
Solids
loading rate »
kg/ (m2) (day)
33.2
47.4
23.0
20.5
24.0
28.4
18.1
37.7
17.6
Mean
cell age »
day
32.4
16.6
3.17
1.58
1.39
0.737
0.525
1.57
0.446
Suspended Solids
mg/1
Tn fluent Effluent
3,370 38
3,860 47
4,610 29
2,850 26
3.180 40
2,180 31
1,380 25
2,810 38
1,390 71
Return
sludge
solids,
mg/1
6,270
9,600
8,770
7,250
8,100
5,070
3,560
7,060
3,590

-------
......  .C9
           70
§0
           10
                                  1       I       I       I
                          a

                        *^^
                         K
                                                              tf
         i      I       ?      8
                        4   iff@ef
                                                8      10


                                                  . BflTI,  fii
                                                               o    jj
                                                                                           @.f
                                                                                           5,



                                                                                           4,
                                                                                           2..I

-------
U)
                 E
                t/v,
                          TTTTTl
I   I   I  I  I  II
   RETURN  SOllDS.
                                                                LUUL
                                                                     10
                                         r
                      20    30  40
  2     345
   WM CELL A6E,
cell  age  on gravity settler  performance
10.000

 9.000

 8,000

 7,000

 8,000

 5,000
                                                                                           4.000   -j
                                  3,000
                                  2,000
                                  i.ooo
                                  0

-------
solids concentrations,, on the other hand,, indicated only a very slight
increase from 30 to 40 mg/1 with increasing sludge age,  It would appear „
therefore 0 that it is possible to achieve acceptable effluent solids con-
centrations with a gravity settler over a vary wide,, i0eop two order© of
saagnitude,, range of \tnatn cell
    To get an indication of the potential advantage of slowly stirring
the settling sludge to effect  a greater sludge compaction, one gravity
settler was equipped with 6035=cra  (2o5-i.no) vertical angle pickets spaced
38.1 cm (15 in0) apart on the  traveling suction arm and extended to within
61 cm  (24 in0) of  the water surface,,  Both settlers were  then operated with
identical feeds ancJ feed rates during Steady-State Runs 3 through 90  The
sludge blanket in  the picket-equipped gravity settler was observed to be
30 to  61 cm  (12 to 24 in0) lower than in the other settler,  A common
sludge sump  for the two settlers prevented ready  analytical verification
of the improved compact ion 0
Pressurized  Eydro°d®nfcrifugal  Screens
     It is believed that vibratory  screening  could be  successfully  used  as
an activated sludge* separation system if  a continuous  cleaning of  screen
surface and  a pressure mechanism were provided 0   Consequently B a greater-
practical filtration  rate  and  higher 'solids  removal  rate  could be
achieved o  A device -consisting of  a screen mounted on discs which  can be
spun in a pressure vessel  appears  to have  potential  as a  mechanical  solids
separation system  for the  high-rate activated sluUge  process 0
     A small  uastewater concentrator was  loaned  from  SWECO for  evaluation o
The  screening surface is mounted  on a vertical  spinning circular cage
with the feed distributed  from- the inside  toward ehe scff®era0   As £he
liquid passes through the  screen  from  the  centrifugal force,,  the solids
are  transported down .-the screen by gravity and  collected  separately 0  A
cleaning cycle is  also built  into the  unit to eliminate grease binding,,
     Unfortunately,, within  the scop® of  this  project p  this eoncspfc  and
umit could not be  tested  or  evaluated;  however „  the  need  for research is
indicated,                                        -  -         •
                                  124

-------
Dissolved Air Flotation
    Dissolved air flotation was selected as an alternative separation
system because it provides larger compactive forces for concentrating
separated materials as compared to conventional gravity clarification.
    The pilot flotator leased from EIMCO was 1.53 m (5 ft) in diameter
and was equipped with a float skimming system, bottom rakes and a draw-
off for settled solids.  The unit was also equipped with EIMCO's stand-
ard two-stage pressurization system for dissolving air in a recycle
stream drawn from the effluent of the unit.  The hydraulic loading of
this flotator was between 20.3 and 122 m /(m)(day) [500 and 3,000 gal/
   2
(ft )(day)] with relatively good suspended solids capture.  If a coagu-
lant aid and polymer were added properly, the solids in the effluent
were well flocculated and could be easily removed by granular media fil-
tration.
    One test run was made on the pilot flotator which was operated at
approximately 81«4 m /(m )(day)  [2,000 gal/(ft )(day)] with 20 percent
effluent recycle.  The ferric chloride dose used was approximately 150
mg/1,, the polymer was  1.0 mg/1 of Calgon Catfloc and the pH of the re-
cycle stream was 8.3.
    The effluent suspended solids concentration was 22 mg/1 with a vola-
tile portion of 5 mg/1.  The low magnitude of volatile suspended solids
would indicate that the solids were  ferric chloride floes rather than
activated sludge solids*.  It appears  that  the flotation system could  be
effective in separating activated sludge.  Moreover,, it is expected  that
a  considerable amount  of phosphate compounds  could be  removed.
    This air flotation solid separation program was only  designed  to
indicate its general feasibility and potential in activated sludge sepa-
ration application.  Complete system evaluation of dissolved  air flotation
is indicated.
                                  125

-------
                              SECTION VIII
                  DESIGN AND  OPERATIONAL  IMPLICATIONS

    The design and operation of domestic waste treatment plants have
evolved largely from practical experience with full-scale systems„
Theoretical analysis has been directed largely to explaining the phenom-
ena observed in practice.  To date such  analysis has not been• fully
applied to either design or  operation of real systems<,  Such a dileraffla
results from the  interaction of several  pertinent considerations0  On®
of the major factors has been the lack of adequate theoretical bases for
analysis of the process.  A  second, and  possibly more important„ factor
has been the poor communication between  the  theoretician concerned pri-
marily with the theory  and performance criteria of the  process and the
practitioner who  is concerned largely with compliance with traditional
treatment  concepts and  effluent quality  or performance  criteria estab-
lished by  regulatory agencies.
    Complete kinetic description  of  the  activated sludge process  that has
been derived from actual plant data would permit evaluation of the  th®o=
retical model and would make possible more accurate  predictions of  process
performance as well as  indicate opportunities  for improved process  design
and operation.  One of  the great  advantages  of using a  rational kinetic
model to describe the activated sludge process is that  it considers both
the microbial kinetic characteristics„ which are a function of the  co®-
plex biological system  operative„  as well as the effect of physical fac=
tors such  as the  hydraulic residence  time, cellular  recycle„ oxygen trans-
fer rates  and the cellular residence  time-   These latter factors  are  af-
fected by  the intentional sludge  wasting rate, the settleability  of the
mixed liquor and  the effectiveness  of  the solids separation system,,

                                   126

-------
KINETIC DESCRIPTION OF ACCELERATED HIGH-RATE ACTIVATED SLUDGE SYSTEM
    The results from this study have yielded a kinetic description of the
accelerated high-rate activated sludge system and what appear to be reas-
onable values for the kinetic constants and coefficients which can be
utilized in the analysis and design of waste treatment systems, especially
for high-rate activated sludge systems.
    The kinetic analyses suggest that the net growth rate of activated
sludge, 1/6 , in a high-rate process is a linear function of the sub-
strate removal velocity, q, and a constant endogenous respiration rate,
kd» or
                            l/8  = Yq -
                               c
In terms of BOD as the rate-limiting substance,
                       l/ec - 0.922 q    - 0.027
 and  in  terras of COD af the rate-limiting substance,

                            - 0.328 q-S-  0,023
    The kinetic  analysis  also  suggests  that  the  organic substrate  concen-
 tration, expressed aslBOD or biodegradable COD,  was  the growth  limiting
 factor in  the  system and  the Micahaelis-Menten  (Monod) model  can be  suc-
 cessfully  employed to  describe the  substrate removal velocity and  sub-
 strate concentration relationship,  viz,,
                                     qs,
 or                               4o1 S1BOD
                           qBOD = 26
                                   127

-------
                         8°*  (S1COD * 20)
                  ?COD ~ 75 + (S     - 20)
    It is believed that much valuable  information wa© developed during
the investigationp not only regarding  theoretical concept®  aad th©ir.
application to the actual process j, but also with respect  to performance
parameters amd operational control of  the  process 6   Table 21  cougars©
values of the design ®ad performance parameters for  £h© accQl@?at©4
high=rate system studied at Chino with other  activated sludg® g>soeees®@0
    The accelerated high=rate  activated sludge process was  characterized
by extremely high loading velocities„  varying from 002 £o 306 (tag BO®)/
(rag MLVSS)(ddy)«  The system was  operated  and produced high quality
effluents (effluent soitsfol® BOB ranged from 5 to 28  eag/1) and .high p?o»
cess efficiencies (75 to 95 percent BOB removal).
    The most significant finding  of this investigation is that  activated
sludge systems can be designed to handle high organic loading©  up to 3»6
(mg BOD)/(sag MLVSS)(day) with  conventional gravity separators operating
                             32                   2
at an overflow rate of  13»4 m  /(m )(day) [330  gal/(ft ) (day)].  Th©  capa-=-
bility of operating the system at the  unusually  low  sssaa  csll ©g© of -003
day demonstrates  the feasibility  of utilizing the high growth=rat©
tial of activated sludge as a  means of removing  oic§gmlc ma&drial© from
wastewater,,  Howevers the oraly practical solids  separation  systsa
able at presen't is a gravity settling  uraito   Sssearch asaid dowei©pkiat
improved gravity  and mechanical cell separators  K©sssiiiB©  ss&
practical need for improved biological treatment sy©e©sss0
                                   128

-------
               T.=>b.le  21..  DESIGN AND OPEFATIONAL  PARAMETERS FOR
                           ACTIVATED  SLUDGE  PROCESSES
                                                         High-rate       China
                      Conventional         Contact       aeration3     demonstration
Parameter          activated  sludge    stabilization -     (optimuta)      (opt.imum)
Mean cell age,
6C, day
BOD loading, l^p
(mg BOD)
(mg MLVSSKday)
MLVSS, Bg/1
Hydraulic resi-
dence time, 6,
hr
Recycle ratio
BOD removal
efficiency, %
5
0.2
1,500
4
0.1
85
to 15
to 0.5
to 3,000
to 8
to 0.3
to 95
5 to 10 -
0.2 to 0.6 1.9
1,000 to 3,000 2,500
(4,000 to lO.OOOr
0.3 to 0.7 0.7
(1.5 to 5)b
0.25 to 1.25 0.56
80 to 90 89
0.4 to 1.0
2.0 to 3.5
600 to 1,000
0.9
0.3 to 0.5
85 to 95C
Secondary clari
 fier overflow
 rate,
 mV(m2)(day)
32.6
32.6
32.6
                                                                          l3.4
sFisret stags performance of two-stage activated  sludge plant (Reference 48).

  Solido stabilization unite

  Soluble BOD removal efficiency.

 Actual operating overflow rate, no optimum tratQ obtained ,
                                  129

-------
APPLICATION OF SYSTM KINETICS
    Inspection of  the cell  continuity equation  (Equation  16) sad
£Jich®0100-ft ) tank for the con-
ventional process„
    Because  of  the prssent dependence upon gravity cell separa£ion0 the
                                   33
high-rat® process  requires© a 685=®  (240200=ft ) secondary settling wait
                    3         •  3
compared to  © 283-a  (IOD000=ft )  unit for eh©' convsneional psocesso '
Hith the d©velibpmesit of compact, hi^h«=rate ssechanical cell separators •
and eh® repl®c<3E3at of eh® larger  gravity s®eelia§ mmi£©0 a coapact
high^rate ac£iv®£csd sludg® plant wieh £h® potential for substantially '
      o^sffali costs could b® realised0
                                  130

-------
Table 22.  DESIGN COMPARISON BETWEEN CONVENTIONAL AND HIGH-RATE
               CHINO ACTIVATED SLUDGE PROCESSES
Design data
and criteria
F, m3/sec
SQ, (mg BOD) /I
YB (mg MLVSS produced)
(mg BOD removed)
kd, day'1
K , (mg BOD) /I
s
*.
QD (mg BOD removed)
(mg MLVSS) (day)
X-, (ing MLVSS)/!
X29 (mg VSS)/!
F B m3/sec
Xr0 (mg VSS)/i
ap (mg 0_)/(mg BOD removed)
bkd!> (mg 02)/(mg MLVSS) (day)
Secondary overflow rate,
m3/(m2)(day)
Effluent BOD, Slt(mg BOD)/!
BOD removal velocity, q.
Conventional
activated
sludge plant
0.0438
200
0.5
0.05
100
3.0
2,000
30
0.0110
7 9000
0.5
0.1
32.6
20
0.5
Demonstration
activated e ludge
plant, Chino
0.0438
200
0.92
0.027
26
4.1
1,000
30
0.0219
4,000
0.44
0.43
13.4
20
1.78
   (mg BOD removed)
   (mg MLVSS)(day)
                                  131

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Table 22 (eomt&nu@d) „  DESIGN COMPARISON SET&JEEM
                             .  Conventional
Design dafca            '          activated
and erifceria
Process efficiency:, Ep %
!*„„ (mg BOD applied)
(mg MLVSS) (day)
Mean eell age9 6CP day
Aeration Sank volunta^
V__ ^
s, ra-3
Hydraulic residence tiats 0
8 „ hr
Sludge wasting rate8
F , m3/day
Sludge production Eates
90 90
O.S6 1.98
5.0 . Oo62
.682 .382
4.3 ;.. i.4-
22.8 127
272 617
      (kg VSS)/day

 Oxygen  requirements;,
      (kg 02)/day                   317
Secondary clarifier surf ace
 areaD m^

Secondary clarifier volume „        283                     685
  areaD m                           116                    281
                                     132

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                            SECTION IX
                             GLOSSARY

a     Oxygen requirement per unit substrate removed
h     Oxygen requirement per unit cell oxidized
C^    Gear reduction efficii-ncy
C     Aerator motor efficiency
E     Substrate or nutrient removal efficiency
F     Influent flow rate
Fr    Return activated sludge flowrate
F     Waste activated sludge flowrate
xj    Decay rate
kt    Oxygen transfer rate
K _   Nonbiodegradable COD concentration
K     Half-saturation constant
 O
Lv    Substrate loading velocity
q     Substrate or nutrient removal velocity
q     Maximum substrate or nutrient removal velocity
Rf    Return sludge ratio
SQ    Influent substrate or nutrient  concentration
BI    Effluent substrate or nutrient  concentration
SVI   Sludge volume index
U     Rate  of oxygen consumption
V     Volume of aeration tank
Xfi    Influent cell concentration
X^    Mixed  liquor cell concentration
X2    Effluent cell concentration
X     Return activated  sludge  cell concentration
Xw    Waste  activated sludge cell  concentration
Y     Yield  coefficient
Yn    Net yield  coefficient
\i     Specific  growth rate
n     Maximum  specific  growth  rate
0     Hydraulic  residence  time
 Q     Mean cell  ape
                                      133

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                                 »o. „
                           3330  12>13
2.   Moraod0 JoD Etedhcigeiss  stsg  la Cgoioeances d@a Cmlfctagqia Bac£Qg&oiBst®a'n  Paris,
                 Ci@B 1942
 3e   M@a©d9 J., "The Growth of Bacterial Cultures9" Aim,, l@Vo McgobAol. 0 _3e

           •0
               .Ao ThQ  Case fog Coatiauoua Flow (Ch®BO@£s£) Kia®£ic
     of Fiamkeoa - Ntatgieafc Ggg^th Ralafcionehipa iia Enaerophieation M®lysaa
     Prepared for Join£ ladysery Govarmogct Coiaffil££©a Meseiag  o®, Algae
              ,, Oiicsgo, Illinois , 1968             '       •
 50   Fsraclj, ZoB "Theoretical Analysis of Continuous Ciaieisff©  Sys£®!EsB" In:
     Theoretical and Methodological Basis fog Consiauonaa Guitar® of Micgo-           '
     oggamistss 0 Ed. 1=  Malek and Z. F@nelD Acsdesdc Press 9 Kew York;, 1966            <

 6.   Stewart 0 MoJ.0 Reaction Kinetics amd Operational Pagaffi@g®r@ of ContianiotBa       ;
     Flow Aaaerobic Fermentation Procesaes. SSRL Publication No. 4S IER' Series
     90 „ University of  California, Berkeley, 1958
 7»   Toari@n0 DoF.0  MusngB CoH>g ^adi«sky0 J.9 P®ffirsonp  E.'A.  ®ad Scherfig0 'J.
     Fisaal Report..,-  ProvJaional Mgai Mgiay ProcsdagsSj,  SHIL  Report Ho._ 7i-6p
     Sanitary Bngineering Esssareh L©boi?©tosy9 Uai^o  of  Calif onai©0 B©rk
-------
13.  Lawrence, A.W. , and P.L. McCarty,  Kinetics of Methane Fermentation in
     Anaerobic Waste Treatment,  Dept. of Civil Engineering, Stanford Univ., 196'

14.  Agardy, F.J., Cole, R.D. , and Pearson, E.A. ,  Kinetic and Activity Param-
     eters of Anaerobic Fermentation Systems,  Fi rs t Annual Report „ Berkeley:
     Sanit. Eng.  Research Lab., Univ. of Calif., 1963

IS.  Metcalf and Eddy, Inc.,  Wastewater Engineering;  Collection. Treatment.
     Disposal,  McGraw-Hill Series in Water Resources and Environmental Engin-
     eering, 1925

16.  Standard Methods fpt the Examination of Water and Wastewater, 13th Ed. ,
     American Public Health Association, AWWA, WPCF, New York, N.Y., 1971       •

i7.  FWPCA Methods for Chemical Analysis of Water and Wastes, FWPCA, Division
     of Water Quality Research Analytical Quality Control Laboratory, Cincinnati
     Ohio, 1969

18.  Patterson, J.W., Brezonik, P.L., and Putnam, H.D., "Measurement and Sig-
     nificance of Adenosine Triphosphate in Activated Sludge,"  Environmental
     Science and Technology . Vol. A,  1970

19.  Beutler, E. , and Baluda, M.C., "Simplified Determination of Blood Adenosine!
     Triphosphate Using the Firefly System," Blood. Vol. 23. 1964

20»  Baer, R.M. 9 "Computer Program COMMON G2 CAL NLIN, Nonlinear Regression/'
     Computer Centert University of California, Berkeley, 1967«


218  Patterson, J.W., Brezonik, P.L. , and Putnam, H.D., "Sludge Activity Par-
     ameters and Their Application to Toxicity Measurements in Activated Sludge,'
     Paper presented  at the 24th  Industrial Waste Conference, Purdue Univ., 1969

22»  Ford, D.L. , Eckenfelder, W.W. ,  and Yeng, T. , "Dehydrogenase Enzyme as a
     Parameter of Activated Sludge Activities," Proc. 21st Annual Industrial
     Waste Conference,, Purdue Univ. ,  1966

23.  Eckhoff, D.W.,  and Jenkins,  D. ,  Activated  Sludge Systems; Kinetics ct  the
     Steady  and Transient States,  SERL Report No. 67-12, Sanitary Engineering
     Research Laboratory, Univ.  of Calif., Berkeley,  1967
24.  Hopwood, A. P.,  and  Downing, A. I,., "Factors Affedi'.^  the Rate of Production
     and  Properties  of Activated Sludge  in Plants Treating Domestic Sewage,"
     J. Indus t. Sewage Purification.  Part 5,  1965

250  Jenkins, D. ,  and Menar,  A.B., The Fate of  Phosphorus  in Sewage Treatment
     Processes; Part 1,  Primary Sedimentation and Activated  Sludge,  SERL Report
     67-6,  Sanitary  Engineering Research Laboratory,  Univ. of Calif., Berkeley,
     1967
                                       135

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260   Heukel@kiaa| H. „  Orford9 H.E. „  and Manganeiii,, Ro 8  "Factors Affecting fch@
      Quantity of Sludge Productioa in the Activated Sludge ProeesSj,"  Sew, ..and
      Indus trial Wastes. £3, 945 9 1951

270   Shea, T.Go,'¥oA.  Pretorius, R.D. Col©, and E.A. Pears©ffl9 Kiaetica of
      Hydrogen Assimilation in Methane Fermentation. SERL Report No.  68-7 ,
      Sanitary Engineering Research Laboratory, Univ. of  Calif. s Berkeley 0
      1968

 28a   Middlebrooks, E.J.,  Jenkins,  D. , Heal,. J. , and Phillips, J. s  "Kinetics
      and  Effluent Quality in Extended Aeration," Water Research, J3»  39 *>
 290   Stewart,  M. J. ,  and Ludwig,  H.F. ,  "Theory of the MAS  Waste=-water Treat-
      ment  Process,,"  Water and Sewage Works,  109, 97 , 1962

 30e   Gram, A.L. ,  Reaction Kinetics of  Aerobic Biological  Processes.  Sanitary
      Engineering  Research Laboratory^  University of California,  Berkeley,
      No. 2, IER Series 90, 1956

 31.   Beneder,  P., and Horvath, I., "A  Practical Approach  to  Activated  Sludge
      Kinetics," Water Research,,  J., 1907

 32.   Pearson,  E.A. ,  and Haas, P.,  Kinetics  Analysis of Whittier Narrows Water
      Reclamation  P^ant .  Report  to Los Angeles County  Sanitation Districts,
      1967

 330   Stack, V.T.  and Conway, R.A. „ "Design Data for Cosipletely-Mised Activated
      Sludge Treatment s"  Sew, and Ind. Wastes , 31, No.  10S  1959

 340   Servicij,  J.A.' and Began,, RoH.9."Free Energy as a  Parameter  in Biological
      Treatment,"   Proc. ASCEn 89 . S.A. 3D pp0 17-40 1963

 350   McWhorter, T.R. , and Heukelekian , H., "Growth and Endogenous . PhAses in
      the Osidation of Glucose B"  Proc. Intl. Conf. .on  Water Follution
      Research , Vol.  2^, pp. 419-345 , Pergaoon Press 1962
 36,   Dryden, F.E.S Barrett, P.M., Kissinger, J.C., and Eckenftslder, W.W.,
      "Treatment of Fine Chemical Wastes by. High-Kate Activated Sludg©9"
      Proc. 9th Purdue Industrial Waste Conference, Purdue Uraiv
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 39.   EIMCO Research and Development Center,  EIMCO-SIMCO Ae rat or',  Palatine,
      Illinois

 40.   Downing, A.L., Tomlinson, T..G. and Truesdale, G.A., Effect of
      Inhibitions on Nitrification in the Activated Sludge Process, 1961

41.   Pearson,  E.A.,  "Kinetics  of  Biological  Treatment,"  Presented at  Special
      Lecture  Series,  Advances  in  Water  Quality  Improvement,  University  of
      Texas, Austin,  Texas  1966

42.   McKinney, R.E.,  "Biological  Oxidation of Organic  Matter,"  in Advances  in
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      Sludge Process.  I., Floe  Producing Bacteria," Sewage and  Industrial
      Wastes.  24. 117, 1952

44.   Greenberg, A.E., Klein,  G. ,  and Kaufman, W.J., "The Effect of Phosphorus
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45.   Helmers, E.N., et^ al.,   "Nutritional Requirements in the  Biological
      Stabilization of Industrial  Wastes.  Ill,  Treatment with  Supplementary
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46.   Simpson, R.W., "Activated Sludge Modification," Water and Sewage
      Works. 106, 421-426, 1959
                                         137

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                               SECTION XI
                                APPENDIX
                     NONSTANDARD ANALYTICAL METHODS

ABENDSINE TRIPHOSPHATE
    The emission of light by  fireflies is known as biolianinescones and
                                                                     t
is an energetic reaction deriving  energy from the hydrolysis of ATP to
ADP and inorganic phosphate.  The  amount of light produced by firefly
extract is directly proportional to  the amount of ATP added.  The reac-
tion involves  the enzyme luciferase8  the bioluoinescent  compound luci-
ferin, and ATP.  Lucif erin  and ATP react in the presence of lucif erase
and' magnesium  ions to form  an enzyme luciferine adenosine monophosphate
complex and  Inorganic phosphate.   The complex is oxidized to pxyluciferyl=
adenylateD followed by  the  release of a quantum of  light„ In the presence
of an arsenate buffer,  there  is an initial burst of  luminescence followed
by an intermediate level of light  emission  that decays steadily with time,,
Procedure
(1)  A 10~ml sample is  added  to 40 ml of Trie buffer in  a 50-ml voluaiet-
     ric flasko
(2)  The ATP is extracted by  immediately placing  the solution in a bo|.l=
     ing water bath for 15  minutes and then transferring it  £o an ice
     bath  for  cooling,
(3)  The volume of the  sample is  restored  to  50 ml  and  the patticulate
     matter  is removed  by  centrifugation or filtration,,
(A)  2 ml  of ATP extract  is added  to 2 ml  of  firefly extract „  The mix-
     ture  is mixed by shaking it  for 15  seconds and at  exactly  two
     minutes the light  emission is measured using  a Turner Flizoiro®s£©Eo
                                   138

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DFHYDKOUENASL ACTIVITY
    Triplit-nyl tetrazoliura chloride (TTC) is reduced to Triphenyl forma-
zan 
-------