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         WATER POLLUTION CONTROL RESEARCH SERIES
170100FV09/70
           PHOSPHATE STUDY AT THE
            BALTIMORE BACK RIVER
        WASTEWATER TREATMENT PLANT
ENVIRONMENTAL, PROTECTION AGENCY • WATER QUALITY OFFICE

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        WATER POLLUTION CONTROL RESEARCH SERIES

The Water Pollution Control Research Reports describe
the results and progress in the control and abatement
of pollution in our Nation's waters.  They provide a
central source of information on the research, develop-
ment, and demonstration activities in the Water Quality
Office, in the Environmental Protection Agency, through
inhouse research and grants and contracts with Federal,
State, and local agencies, research institutions, and
industrial organizations.

Inquiries pertaining to Water Pollution Control Research
Reports should be directed to the Head, Project Reports
System, Planning and Resources Office, Office of Research
and Development, Environmental Protection Agency, Water
Quality Office, Room 1108, Washington, D. C.  20242

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PHOSPHATE STUDY AT THE  BALTIMORE BACK RIVER
          WASTEWATER TREATMENT PLANT
      The  City of Baltimore, Maryland
                   for the

            WATER QUALITY OFFICE

      ENVIRONMENTAL PROTECTION AGENCY
              Program #17010 DPV
              Contract #14-12-4?!
      WQO  Project Officer,  E.  F. Earth
 Advanced  Waste Treatment Research Laboratory
                Cincinnati,  Ohio
                September, 1970
 For sale by the Superintendent of Documents, U.S. Government Printing Office
             Washington, D.C., 20402 - Price $1.50

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                          WQO Review Notice
This report has been reviewed by the Water Quality Office and approved
for publication.  Approval does not signify that the contents necessarily
reflect the views and policies of the Water Quality Office, nor does
mention of trade names of commercial products constitute endorsement
or recommendation for use.

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                             ABSTRACT

Two parallel 10-mgd activated sludge systems at the Baltimore Sewage
Treatment Plant were used in a six-month study to evaluate the effects
of operating conditions and design parameters on the previously ob-
served high degree of phosphorus removal.  An automatic, multi-parameter
monitoring system provided immediate readout and continuous recording
of key operating data.

Suspended solids, wastewater flow, aeration basin mixing configuration,
and dissolved oxygen were evaluated for the effect on phosphorus re-
moval.  Neither suspended solids (1,200 to 3,900 mg/L) nor flow (aera-
tion detention times ranging from 2.7 to 12 hours) showed an influence
on phosphorus removal.  However, changing from plug flow to step aera-
tion or contact stabilization greatly impaired the phosphorus removal.
Low dissolved oxygen levels stimulated sharp releases of phosphorus,
which were accompanied by impairment of organic removal.  Slug wasting
of excess activated sludge also appeared to impair phosphorus removal.

Phosphate removal in the control system averaged 82 percent which is
in sharp contrast to the 15 to 20 percent phosphorus removal capability
that is typical of activated sludge systems and the 9 percent removal
observed in Baltimore's trickling filter.

At Baltimore, operating conditions are specified for maximum phosphorus
removal.  However, no estimate of cost for this mode of operation is
presented because the critical removal of phosphorus from sludge-handling
supernatants was beyond the scope of this study.

The reaction mechanism of phosphorus removal was  not clearly demonstrated.
However, calcium removals showed that calcium phosphate precipitation was
not the principal factor.

This report was submitted in fulfillment of Contract No. 14-12-471,
Program No. 17010 DFV, between the Federal Water Quality Administration
and the City of Baltimore.

Keywords:   Activated Sludge, Aeration, Analysis, Automation,
            Monitoring, Municipal Wastes, Nutrients, Oxygen
            Demand, Phosphorus, Remote Sensing
                               iii

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                             CONTENTS

Section                                                              Page

            ABSTRACT                                                  i ii

            CONTENTS                                                   v

            TABLES                                                   vil

            FIGURES                                                    ix

    I        CONCLUSIONS                                                1

   II        INTRODUCTION                                               5
                          x.
               Theoretical Considerations                              6
               General Study Plan                                      9
               Description of Back River Plant                        10
               Modifications Required for Test Program                1^4-
               Description of Sampling and Analytical System          1J
               Laboratory-Scale Studies                               18
               Data Tabulation                                        18

  III        PRESENTATION OF EXPERIMENTAL RESULTS                      19

               Overall Performance of Control and Test Systems        19
               Specific Parameter Studies                             28
                  Dissolved Oxygen Variation                          28
                  Variation in Suspended Solids                       k-0
                  Variation in System Flow                            k-6
                  Variations in Mixing Configuration                  52
               General Findings                                       60
               Metal Results                                          60
               Miscellaneous Laboratory-Scale Tests                   67
               Comparison Between Activated Sludge and
                 Trickling Filter                                     72
               Correlations of Wastewater Characteristics             75

   IV       DISCUSSION OF EXPERIMENTAL RESULTS                        85

               Demonstration of Full-Scale Activated Sludge
                 Phosphate Removal                                    85
               Definition of Activated Sludge Phosphorus
                 Remova1                                               86
                  Dissolved Oxygen                                    86
                  Suspended Sol ids                                    86
                  Mixing Configuration                                87
                  Flow                                                87
                  Other Factors                                       88
               Optimization                                           88

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                             CONTENTS
                            (cont inued)

Section                                                             Page

    V       ACKNOWLEDGMENTS                                           91

   VI       REFERENCES                                                95

  VII       LIST OF PUBLICATIONS                                      95

 VIII       APPENDICES                                                97
                                v i

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                              TABLES

Table No.                                                             Page

     1          Breakdown of Full-Scale Operation                      11
                Studies of Phosphate Removal

     2          Average Project Operation and                          22
                Performance Conditions

     3          Mass Balance for Phosphorus Removal                    26
                Determination

     4          Typical Profile Analytical Results -                   2?
                Activated Sludge System No. 1

     5          Association of Low Dissolved Oxygen                    37
                Phosphate Release with Reduced Carbon
                Remova1

     6          Relationship Between Soluble Phosphorus                38
                and Dissolved Oxygen in the Activated
                Sludge System

     7          Summary of Profile Results at Various                  kk
                Suspended Solids Levels

     8          Average Operating Conditions and                       Vf
                Performance at Different Flow Rates

     9          Summary of Step Aeration System Profile                56

    10          Summary of Contact Stabilization System                59
                Profile

    11          Average Wastewater Metal Content and                   62
                Cation-Anion Balance

    12          Full-Scale Observation of Changes  in                   66
                Magnesium with Ortho-Phosphate Release

    13          Summary of Weekly Composite Metal                      68
                Analyses

    14          Observations on Metal Content of                       69
                Activated Sludge at End of Aeration
                Tank

    15          Average of Computations on Theoretical                 70
                Accountability for Observed Phosphorus
                Remova1

    16          Summary of Comparison Between Activated                7!).
                Sludge and Trickling Filter Performance

                                 vi i

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                              FIGURES

Figure No.                                                            Page

     1           Flow Diagram - Back River Wastewater                  12
                 Treatment Plant, Baltimore, Maryland

     2           Baltimore Activated Sludge Wastewater                 13
                 Treatment System

     3           Full-Scale Aeration Tank Tracer Studies               l6

     4           Performance of Activated Sludge Systems               20
                 During Study Period

     5           Control Activated Sludge System Phosphorus            23
                 Removal Variability

     6           Control Activated Sludge System Variability           25
                 in  Influent and Effluent Phosphorus
                 Concentrations

     7           D.O. Variation Test No. 1 - Para 1 lei                  29
                 Conditions on Both Systems

     8           D.O. Variation Test No. 2 - Alternating               30
                 Conditions on Both Systems

     9           D.O. Variation Test No. 3 - Gradual                   32
                 Change on Test System

    10           D.O. Variation Test No. k - Rapid                     33
                 Change on Test System

    11           Test Activated Sludge System Outlet -                 35
                 ORP, D.O., and Ortho-Phosphate

    12           Effect of Dissolved Oxygen on Laboratory-             39
                 Scale Batch Aeration

    13           High Aeration Tank Suspended Solids Test              hi

    ik           Low Aeration Tank Suspended Solids Test               h2

    15           Laboratory Batch Tests at Varying Solids              ^5
                 Levels

    l6           Low Flow Operation Test                               48

    17           Diurnal Flow Variation Test                           1+9
                                 IX

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                              FIGURES
                            (conti nued)

Figure No.                                                            Page

    18           Test Activated Sludge System Operated                50
                 at High Flow

    19           Flow Configuration Test No. 1 -                      53
                 Modification of Plug Flow Toward
                 Complete Mixing

    20           Flow Configuration Test No. 2 - Step                 55
                 Aeration

    21           Flow Configuration Test No. 3 -                      57
                 Contact Stabilization

    22           Phosphorus Removal in Laboratory                     6l
                 Systems after Start-up with Full-Scale
                 Activated Sludge

    23           Soluble Metal Ion  Observation Test No. 1             6k

    2k           Soluble Metal Ion  Observation Test No. 2             65

    25           Phosphorus Removal Comparison Between                71
                 Full-Scale and Laboratory Tests

    26           Laboratory Test Phosphate Release                    73
                 on Long-Term Aeration

    27           Correlation Between Ortho- and Total                 76
                 Phosphate

    28           Independence of Phosphorus and Nitrogen              77
                 in Baltimore Wastewater

    29           Lack of Correlation of Total Phosphorus              78
                 with TOC and Suspended Solids

    30           Correlation Between TOC and COD for                  80
                 Primary and Secondary Effluent

    31           Correlation Between TOC and BOD for                  8l
                 Daily Composites of Primary and
                 Secondary Effluent

    32           Comparison Between BOD5 and BOD2o Values             83

    33           Correlation Between Auto-Analyzer COD                84
                 and Manual COD and BOD5

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                            SECTION I

                           CONCLUSIONS

1.  The objective of this study was the full-scale process demonstration
    and evaluation of operating parameters of activated sludge phosphorus
    removal and did not include the theoretical determination of  the
    specific mechanisms or processes that accomplish this phosphorus  re-
    moval.  The long-term observations accumulated in this Study  demon-
    strate that the reality of phosphorus removal at Baltimore and  the
    operating conditions found necessary for optimum activated sludge
    phosphorus removal are within the capabilities of the existing
    Baltimore system.  However, a substantiated explanation of the  pre-
    cise mechanism of phosphorus removal was not found in this study,
    and further study (with this as specific objective) is needed.  At
    Baltimore, long-term calcium and pH observations indicate that
    precipitation of the phosphorus by calcium was not accounting for
    the abnormally high phosphorus removal.

2.  During the last 4 months of the Baltimore field study, when the
    monitoring system was most effective and adequate aeration was
    applied, full-scale control activated sludge system averaged  an
    ortho-phosphate removal of 90 percent and a total phosphorus  re-
    moval of 82 percent.  Ninety percent of the time the system
    removal was greater than 72 percent for total phosphorus.  The
    maximum phosphorus removal observed for any one-month period  on
    the control system averaged 92 percent.

3.  The total phosphorus content of the activated sludge was normally
    between 3 and 5 percent.  The concentration of suspended solids
    in the final effluent was normally between 10 and 30 mg/L.  Thus,
    it would appear that a major portion of the phosphorus in the
    final effluent can be attributed to the phosphorus in the suspen-
    ded solids.  (Filtered and unfiltered analyses were not routinely
    performed on the secondary effluent).

4.  Dissolved oxygen concentrations in the activated sludge aeration
    tank had an important influence on phosphorus removal.  It was
    necessary to maintain approximately 2-3 mg/L of oxygen at the end
    of the plug flow aeration tank to achieve successful phosphorus
    removal.  A significant phosphate release in the effluent was
    caused by lower levels of dissolved oxygen at the end of aera-
    tion, which for the particular aeration tanks under study, repre-
    sented zero dissolved oxygen in a large portion of the tank.  A
    cycle of release and recovery was observed to be reproducible on
    a daily basis.  Limited oxidation reduction potential (ORP)
    observations were made during the low aeration phosphorus
    releases and showed no advantages over dissolved oxygen as a  moni-
    toring parameter for control of this condition.

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 5.   Whenever a phosphorus release related to a low dissolved oxygen
     level  occurred,  an accompanying reduction in carbon removal was
     also observed.   Therefore,  an oxygen-limiting condition appeared
     to  exist on system performance at these times.

 6.   An  automatic sampling and analytical system was developed and
     successfully used to provide immediate knowledge of plant perfor-
     mance  and continuous monitoring data, (particularly on phosphate
     and carbon removal), which  were essential for the daily dissolved
     oxygen variation test.

 7-   The concentration of mixed  liquor suspended solids was not observed
     to  be  an important factor during the study at Baltimore.  Phos-
     phorus removal was successful within the range of 1,200 mg/L to
     3,700  mg/L of suspended solids.  There was some indication that
     phosphorus removal may have been decreased when suspended solids
     concentration was in the 600-900 mg/L range.

 8.   Secondary Clarifier sludge  depth, which was greatly increased during
     bulking conditions, did not affect phosphorus removal.  However, an
     efficient sludge removal mechanism did keep sludge residence time
     to  a minimum in  the Baltimore system.

 9.   Wasting of excess activated sludge at abnormally high rates during
     intermittent periods was observed to upset phosphorus removal;
     therefore, continuous sludge wasting at controlled rates in neces-
     sary for effective operation.

10.   Hydraulic loading variations (diurnal alternations of aeration tank
     theoretical detention time  5.5 to 12 hours, and constant operation
     at  detention times ranging  from 2.7 to 11.5 hours) did not adversely
     affect the activated sludge phosphorus removal.

11.   The mixing configuration in the aeration basin was an important
     factor in the removal of phosphorus.  Only a plug flow configuration
     was successful  during the Study at Baltimore.  Contact-stabilization
     and step aeration configurations were examined in full-scale for
     limited periods  of time and were not successful; contact-stabiliza-
     tion,  step aeration, and completely-mixed configurations were unsuc-
     cessful in the  laboratory.

12.   When phosphorus  removal was taking place in the plug-flow activated
     sludge system,  an obvious release of phosphorus took place at the
     inlet  of the aeration tank, and a subsequent uptake of phosphorus
     occurred at a later point in the flow path system.  A release and
     uptake of magnesium ion coincided with the phosphorus concentra-
     tion pattern.

13.   An  increase in  pH was always observed across the plug-flow aera-
     tion tank, and  maximum pH levels at the end of the aeration tank
     for the study averaged 7.1  and ranged between 6.7 and 7.4.

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14.  Throughout the Study, the primary effluent phosphorus  content  of
     both primary and secondary effluents did not show any  correlations
     with the nitrogenous and carbonaceous substances.

15.  The overall average of metal ion concentrations at Baltimore did
     not appear abnormally high nor show abnormal removals.  The average
     changes in metal ion concentrations for the control system primary
     effluent and the secondary effluent were:  calcium 25.3 and 23.6
     mg/L; magnesium 11.2 and 8.1 mg/L; iron 3.2 and 0.9 mg/L; aluminum
     2.1 and 0.7 mg/L; zinc 1.0 and 0.3 mg/L; and copper 0.4 and 0.1
     mg/L.  The total metal ion removal could, on an ideal  stoichiometrical
     basis, barely account for the phosphorus removal.

16.  Long-term sampling of the low-rate trickling filter system at  Balti-
     more indicated a 9 percent phosphorus removal, which was the approxi-
     mate quantity required for biological synthesis in the system.

17-  The phosphorus removed in the Baltimore activated sludge system is
     transported in a phosphorus^rich excess activated sludge stream,
     and the overall flow configuration of the Baltimore Back River Plant
     is such that only approximately 12 percent of any phosphorus released
     in subsequent sludge handling operations returns to the activated
     sludge system.

18.  The added cost for full development of effective activated sludge
     phosphorus removal at Baltimore (or other possible conventional
     activated sludge systems) would include the expense necessary  to
     prevent recycle of soluble phosphorus degradation products from
     sludge handling operations and the expense for minor aeration  tank
     modifications and providing adequate aeration capacity.

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                            SECTION  II

                           INTRODUCTION
The water quality of a number of streams and  lakes  is  currently  deteri-
orating because of increased algal and plant  growth.   An  increase  in
the phosphorus content of these waters frequently has  been  cited as the
cause for these changes, and as a result, some regulatory agencies are
requiring a high degree of phosphorus removal in the treatment of
domestic wastewaters.  When secondary biological treatment  is applied,
domestic wastewaters are deficient in carbon  and rich  in  phosphorus
and nitrogen for normal microorganism needs.  In general, the secondary
treatment of domestic wastewater by the production  of  microorganisms
(such as activated sludge) will satisfactorily remove  most  of the  organic
carbon but will usually produce an effluent which still contains a
large proportion of the incoming phosphorus and nitrogen.

However, a limited number of existing conventional  activated sludge plants
across the United States have demonstrated abnormally  high  phosphate
removal efficiencies, without the specific addition of chemical  precip-
itating agents.  Since there is a potential for application elsewhere
of this approach to significant reduction of  phosphorus,  there is  inter-
est in full-scale, long-term demonstration, definition, optimization,
and specification of critical operating and design parameters for  this
process.

The project objectives of the field study at  the activated  sludge
portion of the Back River Wastewater Treatment Plant in Baltimore,
Maryland (by the City of Baltimore, under the technical direction
of ROY F. WESTON) are as follows:

     1.  Process Demonstration - To observe phosphorus removal
         over a sustained period, with intensive monitoring
         of operation and treatment parameters.

     2.  Process Definition - To further define the limita-
         tions on input conditions under which phosphorus
         removal can be accomplished in a continuous flow,
         full-scale, conventional activated sludge process
         by investigation of parameter interactions and
         process kinetics.

     3.  Process Specification - To verify and quantify
         within the limitations of available  facilities,
         the specific design and operating parameters  of
         the treatment system for possible application to
         phosphorus removal at other wastewater treatment
         plants.

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                    Theoretical Considerations

An activated sludge plant treating domestic wastewater normally achieves
a phosphate removal of 20-30 percent.  However, at least five conventional
activated sludge plants at different locations across the United States
have been documented as achieving a phosphate removal of 60-95 percent
consistently.  The currently-advocated theoretical explanations for this
high phosphate removal phenomenon can be grouped in two categories:   1)  the
occurrence of luxury biological uptake and biologically-enhanced pre-
cipitation of phosphate; or 2) metal precipitation of phosphorus,  dependent
on the mineral content of the wastewater and essentially independent  of
the presence of biological organisms.  Either of these explanations could
account for the soluble-to-solid transfer of phosphate phosphorus  in  the
activated sludge process; however, the two explanations do  represent
significantly different implications on the manner and extent to which
this phosphate removal process can be applied to domestic wastewater
treatment.  If the phosphate removal mechanism is a true luxury biological
uptake phenomenon dependent primarly on the biological solids present,
the process should be applicable to any domestic wastewater where  the
appropriate process design and operating conditions are maintained to
grow the desired biological population.  However, if the phosphate removal
mechanism is largely one of chemical precipitation and a function  of  the
specific mineral content of the wastewater, application of  this process
would be restricted to those areas where the "correct" wastewater
characteristics are available.

In the literature, probably the first use of the luxury biological phos-
phorus uptake explanation for the phosphate removal in the  activated
sludge process was that of Levine and Shapiro (1).  They observed  very
high phosphate removals by activated sludge in batch studies.  As  a
mechanistic explanation they hypothesized that in aerobic utilization of
carbohydrates, the high participation of phosphorus in metabolism  and the
metabolic intermediates favor the luxury uptake of ortho-phosphate in
microorganisms.  Their batch experiments showed that this phenomenon
was dependent on the dissolved oxygen concentration.  To confirm the
biological nature of the observed luxury phosphorus uptake, they signi-
ficantly diminished the phosphorus removal in activated sludge by  adding
small amounts of dinitrophenol, which specifically inhibits biological
oxidative phosphorylation.

Smith, et al.  (2) similarly found that the presence of dinitrophenol  in-
hibited the  formation of intercellular volutin granules and the associ-
ated increase in total phosphorus content of cells in pure  culture of the
common bacteria Aerobacter Aero genes.  They observed that an aerobic
subculture of Aerobacter Aerogenas (cultivated on a phosphorus media)
growing on adequate media showed a 2- to 3-fold increase in total
cellular phosphorus, a 200-fold increase in intercellular inorganic
meta-phosphate, and the production of many intercellular volutin
granules.  In their experimentation, they found volutin granules were
produced only if sufficient glucose, phosphorus, magnesium, and potas-
sium were present in the media.  This phosphate-starved activation

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property for subsequent 2- to 3-fold increase in cellular phosphorus has
been reported by Borchardt et al.  (3) for algae grown in both light and
dark conditions.

Furthermore, Harold  (4) described  intercellular volutin as consisting
mainly of inorganic  poly-phosphates including some magnesium, protein,
lipid, and other substances.  He indicated that the use of the enzyme
phosphate kinase appeared to be the only pathway for the biosynthesis
of long-chain poly-phosphate molecules; the presence of magnesium is
required for this particular enzyme activity.  Although poly-phosphate
kinase was first identified in yeast, it is widely distributed among
microorganisms, many of which are  very common in the activated sludge
biomass.  There are  many cellular  enzymes that can be found to degrade
poly-phosphate molecules, indicating that there is no problem in the
re-utilization of phosphorus stored in the poly-phosphate form.

In contrast to the above approach  is the theoretical explanation involv-
ing chemical precipitation.  This  position is most clearly described by
Menar and Jenkins (5), who hypothesize that phosphate removed in excess
of that predicted by biological growth requirements (to produce an acti-
vated sludge of 2 to 3 percent phosphorus content) is accomplished by
chemical precipitation, with the phosphate precipitate becoming physically
entrapped in the matrix of the activated sludge floe and removed in the
waste activated sludge stream.  There is some claim that the activated
sludge provides seeding or nuclei  for the precipitate.  In hardwater
sewage, a significant part of the  removal of phosphorus is thought to
be caused by calcium precipitation.  For this case, the hypothesis is
that since calcium phosphate precipitation is a function of pH and
since carbon dioxide stripping occurs in the latter phases of aeration
in an activated sludge aeration tank, the pH is increased sufficiently
to cause calcium precipitation.  In some full-scale activated sludge
systems where high phosphorus removal has been observed, significant
removals of calcium  have been associated with the phosphorus removal.

This chemical precipitation theory is supported by Ferguson et al. (6),
who state that low magnesium and low carbonate concentrations encourage
higher removals by calcium phosphate precipitation.  They also found
that the presence of calcium phosphate seed particles accelerated the
calcium removal of phosphorus in sterile wastewater free of biological
activity.

A high degree of phosphorus removal from municipal wastewaters by
conventional activated sludge plants has been observed at San Antonio,
Texas (7); Milwaukee, Wisconsin (8); Amarillo, Texas (9); Ft. Worth,
Texas (9); and Los Angeles, California (10).  Probably the most widely
publicized cases of  full-scale phosphate removal is that at San Antonio,
Texas.  One of three parallel activated sludge plants at the San Antonio
Wastewater Treatment Plant has been observed to remove consistently a
much higher percentage of phosphate than the two similar parallel plants.
In all three plants, the supernatant or filtrate from the sludge-handling
operations is not returned.  As a  result, a number of studies have been
performed to evaluate significant  parameters and operating aspects
responsible for the  differences in phosphorus removal.

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Dissolved oxygen levels in the aeration of activated sludge have received
considerable attention, and Wells  (11) illustrates and discusses the re-
lease and uptake of phosphates by  the San Antonio activated sludge plant
during periods of aeration and non-aeration.  The effect of aeration tank
suspended solids concentration was also studied at San Antonio; in
work presented by Witherow (9) , increase of the aeration tank suspended
solids concentration from the 500-1,000 mg/L range up to the 1,500-2,000
mg/L range increased the phosphorus removal in one of the San Antonio
activated sludge plants (that normally achieved only a 30 to 40 percent
reduction) to more than 90 percent.  Many other operating parameters
have been evaluated at San Antonio and have been the basis for a number
of laboratory investigations.  Yet, a full explanation of the phenomenon
and definition of design parameters have not been achieved.

Efficient phosphorus removal in the activated sludge portion of the
Baltimore, Maryland Back River Wastewater Treatment Plant was first
reported by Alarcon (12) in 1961.  He observed fluctuations in phosphorus
removal which he suspected were associated with fluctuations in the  rate
of aeration.  Confirmation of the  high phosphorus removal at Baltimore
was reported by Scalf et al. (13); during a two-week period in April 1967,
the Baltimore activated sludge plant showed consistent phosphate removals
of more than 90 percent.  This particular study was performed by the
Federal Government in a series of  amenability tests for selection  of a
full-scale research plant to further specify, define, and optimize the
parameters of the activated sludge phosphate removal process.  As  further
confirmation for approving the research contract for the study described
in this report, an additional series of samples from the Baltimore Back
River Wastewater Treatment Plant,  analyzed during the period May 13-23,
1968 by the Federal Government, again showed a consistently high degree
of phosphate removal.  After preliminary approval on October 15, 1968,
the research contract for the extended full-scale demonstration and
definition of phosphate removal was formally authorized on December  27,
1968 to the City of Baltimore, which then sub-contracted the majority
of the services to ROY F. WESTON of West Chester, Pennsylvania.

To achieve conclusive documentation of full-scale performance, a major
portion of the contract was devoted to the development and use of  an
extensive instrumental monitoring  system.  The monitoring system con-
sisted of a multi-point automatic  sampling and collection system with
automatic introduction to multi—parameter, continuous analytical instru-
mentation.  The complex nature of  this system involved considerable  time
to assemble, perfect, and make operational.

The selection of the Back River Wastewater Treatment Plant at Baltimore
for this  study was based on the fact that it had two easily separable
10.0 mgd  activated sludge systems, which amounted to only 10 percent of
the total plant flow, permitting flexibility in operation.  Some minor
modifications were necessary to completely separate the two activated
sludge systems.  This likewise contributed to the necessary lag before
the commencement of the full-time  field portion of the study.

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The original plan of project  activities  called  for  four months for the
delivery of equipment,  setup  of  laboratory  and  analytical systems,
training of personnel,  and  the completion of  the  plant  modifications.
This was to be  followed by  a  ten-month field  study  period for full-scale
investigations.  The actual sequence  of  project activities was as  follows:
      Time
    Feb. 1969
    Mar. 1969
    Apr. 1969
    May 1969
    June 1969
    Dec. 1969
    Jan. 1970
    Feb. 1970
          Activity

Chemist and laboratory assistants
on-site to begin training and set-
up temporary laboratory.

Temporary laboratory completed
and project engineer on-site.

Activated sludge plant modifica-
tions completed and Technicon
autoanalyzers installed.

Leakage between full-scale sys-
tems corrected and last of sam-
pling and analytical equipment
delivered.

All monitoring systems made
operational and full-scale
formal experimental study ini-
tiated.

Termination of formal full-scale
studies.

Data tabulation and equipment
inventory for closure of tem-
porary field laboratory com-
pleted.

Two weeks of final tests on
metal concentrations and la-
boratory studies.
This was the extent of the field activities at Baltimore, and  the remain-
ing project activities for data analysis and report completion have been
performed at ROY F. WESTON's West Chester, Pennsylvania Offices.

                        General Study Plan

The general approach used for the formal field experimental portion of
this project was operation of one half of the activated sludge facilities
(System No. 1) as a control at the normal conditions used at Back River.
The second portion (System No. 2) of the activated sludge plant was used
as the test system, with the desired variations in pperaing conditions

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being imposed for periods of one to three weeks.  The actual study plan
on the test system during the formal experimental portion of this pro-
ject is listed in Table 1.  During the period indicated  (6/23/69 to
12/22/69) , the control system was operated and monitored except between
12/6/69 and 12/22/69, when the No. 1 aeration tank was taken out of  ser-
vice to permit the desired variations in aeration tank mixing  configura-
tion.

The operating conditions included in the formal  full-scale  study con-
sisted of:  baseline operation determination; low and cyclic dissolved
oxygen levels in aeration tank; low and high levels of suspended solids
in the aeration tank; low, high and diurnally-varied flow  to the systems;
and modifications of the conventional activated  sludge operation to
step aeration, contact stabilization, and toward complete mixing.  This
range of conditions included all the initially proposed  studies with the
exception of the substitution of mixing configuration tests for a
phosphorus addition test and an organic carbon dilution  test.  Other
studies originally discussed, such as varying the phosphorus-to-calcium
ratio by lime addition, or reducing the aeration tank pH by the addition
of acid, were not included in this study.  The reason for  this departure
from the original study plan was the agreed-upon interest in variations
in mixing configuration.

                  Description of Back River Plant

Before describing the necessary plant modifications at the  activated
sludge portion of the Back River Wastewater Treatment Plant, limited
definition of the overall system is necessary.   A block  flow diagram of
the overall Back River Wastewater Treatment Plant is shown  in  Figure 1.
The plant currently treats approximately 170 mgd; secondary treatment
is by trickling filter for 150 mgd and by activated sludge  for the
remaining 20 mgd.  All excess secondary sludge is piped  back to the
plant inlet chamber ahead of the primary clarifiers.  As a  result, the
activated sludge section of the treatment plant  receives approximately
12 percent of the supernatant liquid associated  with the waste activated
sludge.  Current sludge-handling practices at the Back River Wastewater
Treatment Plant include the use of five heated anaerobic sludge digesters,
which have a capacity  (and are operated at that  capacity) of half  the
current sludge production.  The raw and digested sludge  after  storage
is elutriated and polymer is added prior to vacuum filtering and drying.
The principal liquid streams from the sludge-handling facilities returned
to the plant inlet chamber are the elutriation water and the vacuum  fil-
trate.

An expanded flow diagram of the activated sludge part of the plant  is
shown in Figure 2.  The common primary effluent  flows by gravity into
the  two 2.6-million gallon aeration tanks, with  air applied through
fixed diffuser plates  of varying porosities to apply tapered aeration.
At the overflows from  the aeration tank, the mixed liquor  flows to  two
126-foot diameter circular final settling tanks  with side wall depths
of 13 feet each.  The  final secondary effluent from the  center-feed,
peripheral-overflow clarifiers flow to Bethlehem Steel for  industrial
                                 10

-------
                         Table 1

      Breakdown of Full-Scale Operation Studies of
                   Phosphate Removal
P roj ec t
Period
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
Starting Dates   Description of Test System Operation
 6/23/69
 6/30
 7/7
 7/29
 8/23
 9/3
 9/13
 9/29
10/13
10/20
10/27
11/2
11/10
11/18
11/27
12/5
12/11
12/16
12/17
12/22
Base-1ine Data
High Dissolved Oxygen(D.Oj
Variation in D.O.
Low Aeration Tank Suspended Solids
High Aeration Tank Suspended Solids
Low Primary Effluent Flow
High Primary Effluent Flow
Diurnal  Flow Variation
Parallel  D.O. Variation of System
Alternating D.O. Variation of System
Gradual  D.O. Variation
Low Flow and System Recovery
Rapid D.O. Variation
Plant Modification Time
Modification Toward Complete Mining
High Flow with Two Clarifiers
Step Aeration
Normal  Plug-Flow Recovery
Contact Stabilization
Return to Normal Plug-Flow Operation
                             11

-------
            ACTIVATED SLUDGE  SYSTEM
            EXCESS  ACTIVATED  SLUDGE     I
                   REVOLV ING
                   SCREENS
                                                                            SETTLED SLUDGE
                                     RAW OR DIGESTED SLUDGE
                                                                                SLUDGE
                                                                                TANK NO 26
                     SEVEN
                     PR IMARY
                     CLARIFIERS
                                                                                 DRIED SLUDGE
                                          SLUDGE ELUTRIANT AND
                                                     F ILT^ATE
                                                                                               H LE HEM
                                                                                             STEEL CO .
                                                                                             TREATMENT
                                                                                             PLANT
                                                                              SLUDGE DRYER BLDG.
                                                                              VACUUM F ILTER BLDG.
ELUTRIATION TANKS
BACK RIVER  WASTEWATER  TREATMENT PLANT,  BALTIMORE,  MARYLAND
                                         FIGURE  1

-------
CO
                                        BAFFLE WALL
                        |   AERATION TANK  |      —».
                               NO. 2
                        |  AERATION TANK  |       «—
                        I       NO. 1
                                                        CONTROL
                                                        BUILDING
RETURN SLUDGE WELL
                                                                               SETTLING TANKS
                                                                           NO. 2             NO. 1
                                                              EFFLUENT
                                      FINAL
                                     EFFLUENT
       0   25  50  75  100
          SCALE IN FEET
                         BALTIMORE  ACTIVATED SLUDGE WASTEWATER TREATMENT SYSTEM

                                                       FIGURE 2

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water reuse.  The sludge from the center sludge wells of the  final  clari-
fiers flow by gravity to the lower return sludge wells in  the  control
building.  Two return sludge pumps transfer the sludge to  the  upper wells
in the control building from which it flows by gravity to  the  inlet of  the
aeration tanks.  Excess return sludge is pumped from the upper return sludge
well to the plant inlet chamber before primary clarification.

The activated sludge plant was built in 1939 and contains  some unique
features.  In an effort to reduce short circuiting, each aeration tank
was constructed with a length to width ratio of 25:1 and contains four
intermediate transverse baffles as indicated in Figure 2.   These baf-
fles are 12 feet wide in the approximately 30-foot wide aeration tank
width and extend the full 15 feet liquid depth of the tank.   Likewise,
the turn-around point at the end of each aeration tank is  compressed
to a 10' x 10' port to minimize short circuiting.  Another unique feature
of this activated sludge system is in the final clarifiers;  the plow-type
sludge collection mechanism is a four-arm apparatuus instead  of the com-
mon two-arm collector.  This was installed to insure rapid transfer of
sludge from the periphery to the center sludge collecting  well.   The
activated sludge system, as installed, included piping and control
building facilities for a mirror image 20-mgd expansion of aeration
tanks and clarifiers on the north side of the existing system.

              Modifications Required for Test Program

The actual plant modifications required to establish two independent
activated sludge systems primarily involved in separating  the  two return
sludge streams by placing the north lower and upper return sludge well
system in use.  Specifically, this involved:  extending the No.  1 clari-
fier return sludge line to the northern lower sludge well; extending
the suction line for one of the return sludge pumps to the northern
lower return sludge well; connecting the discharge of that return sludge
pump to the northern upper return sludge well; and extending  the No. 1
aeration tank return sludge line to the northern upper return sludge
well.  The northern and southern return sludge wells had to be block-
boarded apart, and the overflow chamber for the outlet of  the  two aera-
tion tanks had to be block-boarded between the two transmission lines
to the final clarifiers.  To achieve positive sludge-wasting  measure-
ments, two V-notch weir collection chambers with level-recorders were
installed in the upper return sludge wells.  These modifications were
accomplished without taking the activated sludge system out  of service,
by using the system drain pump and by diverting the return sludge from
the clarifiers directly to the drainage well.

The modifications needed to accomplish other aeration tank mixing
configurations were also comparatively minor.  A temporary dam was
placed across the unused portion of the common primary effluent
channel just north of the aeration tank inlet line shown on Figure  2.
This unused portion of the inlet channel, which receives the  discharge
from the 8-mgd drainage pump, had its sidewalls elevated by 18" so
that flow could be directed through a 4'-wide trough to the  unused
center "Y" section dividing Aeration Tank No. 1 from Aeration Tank
No. 2.  Three-foot wide by one foot high rectangular openings  were

                                14

-------
then made in the side of  the  "Y" section  so  that  flow  could  be  di-
rected into Aeration Tank No. 2 either at  the head  end or  down  at
the halfway turn around point, after being transferred the length  of
the aeration tank in the  unused "Y" section  of  the  dividing  wall.

The modification for complete mixing was  achieved by pumping approxi-
mately 8 mgd from the end of  the aeration  tank  directly to the  beginning
of the aeration tank, using the outlet tank  drainage line  and the  modi-
fied drainage pump system.  To prepare for step aeration and contact
stabilization, Aeration Tank  No. 1 was taken out  of service  and used
to transfer primary effluent  directly to  the drainage  pump system;  this
was accomplished by lowering  the liquid level to  prevent overflow  at
the outlet point, by decreasing the aeration tank suspended  solids  to
less than 1,000 mg/L, by  reducing the aeration  to a very low level, and
by opening the drain line to  the drainage  well  at the  inlet  of  the
aeration tank next to the primary effluent inlet  port.   Step aeration
was achieved by feeding approximately 7 mgd  through the normal  primary
effluent line at the inlet to Aeration Tank  No. 2 and  feeding another
7 mgd of primary effluent through the modified  drainage pump system to
the mid-point of Aeration Tank No. 2.  The final  modification for  con-
tact stabilization was accomplished by having the first half of the
aeration tank receive only about 4-1/2 mgd of return sludge  (which  pro-
vided about 6-hour aeration time) and by  introducing 8 mgd of primary
effluent through the drainage pump modification transfer system at  the
mid-point of Aeration Tank No. 2 (which provided  about 3 hours  of  con-
tact time).

As would be expected from the long, narrow aeration tanks  with  inter-
mediate baffles, a high degree of plug flow  is  achieved at the  Baltimore
activated sludge plant.   In the previous  study  published by  Scalf  et al.
(13), tracer studies of the aeration tank  response  indicate  modal  deten-
tion times that closely approach the theoretical  system detention  time.
In order to confirm these previous observations and define the  changes
imposed by the above mixing modifications, additional  aeration-tank
tracer studies were performed, with results  as  shown in Figure  3.
Fluorescein was used as the tracer in one  of these  studies and  lithium
ion in the others.  Outlet tracer response to a slug introduction  of
tracer at the inlet of the aeration tank  showed good agreement  with
theoretical detention times for all cases  studied.  As indicated in
Figure 3, the modification for complete mixing  did  reduce  the modal
tracer detention time to  3.1  hours from a  normal  modal detention time
of about 5 hours, but addition of the 7 mgd  pumped  from the  outlet  to
the inlet makes the theoretical detention  time  3.3  hours,  which is
comparable to the observed modal detention time.  The  secondary peak
in this tracer response is merely the second cycle  of  the  material
through this system.

The final aspect of the activated sludge  system that was involved  in modi-
fication was flow measurement.  To assure  accurate  flow measurements and
records during the study, considerable instrument mechanic effort was
devoted to modification and calibration of these  instruments while  the
initial plant modifications were being made.  After this calibration


                                15

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20
 05
 00
        I      I

     • AERATION
     A AERATION
       NORMAL PLUG FLOW
       6/3/69  10:00  AM_|       NU 1  NO.2
       MODAL  TRACER DETENTION TIME 5.2  4.8 HRS.
     DERATION TANK THEORETICAL DT 6.5  6.0
                                                  1
                  '
                                            PLUG FLOW (HIGH HYDRAULIC LOADING)
                                             2,'11/69  2:00 AM
                               NO. 1  NO.2
                                             MODAL TRACER DETENTION TIME  —   2.5 HRS.
                                             AERATION TANK THEORETICAL DT  —   2.6 HRS.
                                       i	1	1	1
                                      MODIFICATION TOWARD
MODAL TRACER DETENTION TIME          —
AERATION TANK THEORETICAL DT         —
AERATION TANK THEORETICAL DT (4 7.0 MGD)-
                                                                          3.1  HRS.
                                                                          5.2  HRS.
                                                                          3.3  HRS.
                                                             -I
 I      I      I      I
CONTACT STABILIZATION
(3 4 MGD RETURN SLUDGE IN BEGINNING
\ 8.0 MGD PRIMARY EFFLUENT IN MIDDLE)
12/18/69  10:00 AM
                                       CONTACT PORTION MODAL TRACER DT
                                       CONTACT PORTION THEORETICAL DT
- J^

1 1 1 1 1 1 1 1
                     34567
                           TIME.  HOURS
                    (FROM  SLUG  TRACER  ADDITION)
                        10
FULL-SCALE  AERATION  TANK TRACER  STUDIES
                          FIGURE  3
                                    2.5 HRS
                                    2.7 HRS.
                               —16—

-------
effort had been  completed  and just before the  initiation  of  the  formal
study, a  series  of  lithium-dilution  flow measurements were performed  to
check the primary effluent and  return-sludge Venturi flow-measuring and
recording instruments.  The lithium  data showed  that the  flow meter
accuracy  was  satisfactory  in all  cases, and the  actual  results are
tabulated in  Table  A-l.

          Description of Sampling and Analytical Systems

For this  project, a special monitoring system  was designed and installed
for continuous operation with automatic hourly retrieval  at  as many as
eleven sample points located at various parts  of the treatment plant.
The eleven permanent sampling points included:   the common primary
effluent  to the  activated  sludge  system; the two final  clarifier  over-
flows, the two return sludge streams (collected  for each  system at the
two upper return sludge wells); and  inlet, middle, and  outlet portions
of each of the two  aeration tanks.  All samples  were pumped  to a  central
location  and  processed by  an automatic switching system,  which collected
samples for daily composite analyses and sequentially introduced  samples
and standards to continuous analytical instrumentation.

The parameters measured and recorded on a continuous basis were:  flow,
pH, turbidity, total dissolved  carbon, dissolved COD, nitrite-nitrate,
ammonia,  ortho-phosphate,  and on  a less frequent basis  total phosphorus
and total Kjeldahl  nitrogen.  Measurements made  on the  daily composited
samples from  the automatic refrigerated collection system included:   sus-
pended solids, total phosphorus,  total Kjeldahl  nitrogen, and BOD.  Spe-
cific metal ions were routinely measured on weekly composite samples  and
on selected grab samples.   Since  this sampling and analytical system was
especially designed and developed for this project, a detailed descrip-
tion of the monitoring system is  included as Appendix B.

The ortho-phosphate, ammonia nitrogen, combined  nitrite-nitrate,  and  COD
were measured by standard  Technicon  auto-analyzer methods.  The total
phosphorus and total Kjeldahl nitrogen were measured by a specially-
developed simultaneous Technicon  auto-analyzer system,  which used a
rigorous  digestion  procedure of perchloric acid  and vanadium pentoxide.
The Union Carbide total carbon  analyzer had to be modified to determine
on an interim manual basis the  total inorganic carbon.  These methods
and equipment are also summarized in Appendix  B.  Metal analysis  for
calcium,  magnesium,  iron,  aluminum,  zinc, copper, and sodium were deter-
mined by  atomic  absorption methods.  Where total metal  ion contact was
desired,  a digestion procedure  using a mixture of hot sulfuric and nitric
acid was  used; in this procedure, special consideration had  to be given
to sulfate correction for  determination of calcium.  The  BOD procedure
was modified  in  selected test samples by adding  thiourea  to  supress
nitrification in an effort to measure long-term  carbonaceous BOD.  All
standard  manual  laboratory measurements were made in accordance with
Standard  Methods for the Examination of Water  and Wastewater, 12th
edition (14).  Suspended solids measurements performed  (six  times a
day on samples from the outlet  of the two aeration tanks) by the  acti-
vated sludge  operating staff for  normal control  purposes  have been used
in this report.

                                17

-------
The experimental nature and magnitude of the monitoring system imposed
certain constraints on its operation.  The mode of operation of the
continuous automatic sampling and analytical system was a four-day
week (from 10:00 a.m. Monday morning continuously through 10:00 a.m.
Friday morning).  This schedule was selected because of project manpower
limitations for system maintenance and because of the requirements for
tabulation of analog chart outputs.  During the first 16 weeks of the
formal research study, the sampling system was operated on all eleven
sampling points; however, sample introduction to the Technicon and
Union Carbide analytical systems was on a manual basis after certain
necessary sample preparation measures (involving suspended solids re-
moval) had been performed.  During the final ten weeks of the study,
the sampling system was operated on three sampling points (the common
primary effluent and the two secondary effluent sampling points) .  With
the reduced level of suspended solids, the Technicon and Union Carbide
systems were operated on an automatic basis in conjunction with the
other instrumentation and sample collection activities.  This terminal
mode of operation provided the excellent operating aid of knowledge of
phosphate and total carbon performance approximately 10 minutes after
respective position sampling times.

                     Laboratory-Scale Studies

Although most of the effort in this research project was devoted to the
full-scale research study, limited laboratory-scale studies were also
conducted.  These included:  assessment of the effects of the level of
dissolved oxygen during aeration; the effect of various mixing configura-
tions on phosphate removal; and limited batch studies on other aspects
affecting phosphate removal.  The batch studies were performed in 5-liter
aeration vessels, and the continuous laboratory-scale studies were per-
formed in a system containing a 12 liter aeration volume and a A.5-liter
secondary settling tank.  A modification using the Technicon sampler per-
mitted the hourly sampling of the laboratory-scale activated sludge system.

                          Data Tabulation

For feasible retrieval, the automatic monitoring data were tabulated and
transferred to computer cards which located the data by date, time, sam-
ple point, and parameters.  The data placed on the computer cards included
flow, dissolved oxygen, pH, COD, total carbon, ortho-phosphate, ammonia
nitrogen, and combined nitrite-nitrate nitrogen.  The formal project data
occupied approximately 50,000 computer cards, and a complete computer
print-out grouped in weeks of the formal research study period is trans-
mitted as a master data set volume.  Additional computer-handling oper-
ations that have been performed on the data have been limited to mean-
ingful weeks of data and have consisted of ranking, producing probabil-
ity of occurrence plots, and extending the data to pounds/day.  The sig-
nificance of overall statistical analysis of the data is limited due to
gradual trends in the activated sludge system and the long response time
to variables artificially imposed on the activated sludge system.  There-
fore, considerable attention has been placed on chronological plotting
of the full-scale monitoring data.

                                18

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                            SECTION III

               PRESENTATION OF EXPERIMENTAL RESULTS

The results for the full-scale demonstration of phosphorus removal in the
activated sludge process refer chiefly to the formal study period of
June to December 1969, but also include limited observations made during
February 1970.  The experimental results will be presented in terms of
a review of the overall performance of the control and test systems,
a presentation of specific parameter tests (including dissolved oxygen,
suspended solids, flow and mixing configuration), and other general
findings,  including metal observations and limited laboratory results.

The data presented in the text are limited to summary tables and figures
supporting significant observations.  Complete monitoring data for the
entire period of the study are tabulated in a separate volume, and Ap-
pendix A of this report includes such detailed data as:  all analyses
performed on composite samples, metal results performed on weekly
composite samples, complete observations on overall plant samples
comparing trickling filter and activated sludge system performance,
average system performance for the 19 significant test periods outlined
in Table 1, and the results of 21 profile studies taken across the acti-
vated sludge systems.

          Overall Performance of Control and Test Systems

A summary of the activated sludge system performance for the formal study
period is presented in Figure 4.  Results for both systems are indicated,
with the narrow solid line corresponding to the control system (System
No. 1) and the heavy solid line pertaining to the test system (System
No. 2).  Plotted daily averages include:  percent total phosphorus re-
moval; percent BODc removal; dissolved oxygen level in the outlet of
the aeration tank; suspended solids level in the aeration tank outlet;
and the primary effluent flow to each system.  Both systems responded
similarly prior to 11 August 1970, when use of a second diffused air
blower was initiated to assure adequate aeration during times of peak
organic loading.  After that time, a significant improvement in acti-
vated sludge performance took place.  Therefore, for a four-month period
beginning in the mid-August a high level of total phosphorus removal
was maintained in the control system, with the exception of September 9th
(when the dissolved oxygen dropped very low) and October 7th and 21st
(when a release of phosphorus was deliberately caused in the control sys-
tem by reducing the aeration).  This latter test was run to demonstrate
identical responsiveness in comparison to observations made on the test
activated sludge system.  It should be noted that all values plotted on
Figure 4 are daily averages or daily composite analytical results.

The BOD removal of the two systems ranged from 65 to 97 percent during
the study period, and most of the time was above 85 percent.  At times
of low dissolved oxygen at the outlet of the aeration tank, the BOD
removal showed obvious impairment.  The inlet BOD strength in the
primary effluent varied from 57 to 380 mg/L, which accounted for some
                                19

-------
     IC51 PERIOD
    n  i  r~r
                 I  9  1  10 I  II  I  il 1  13I  14I  15  I 16 I II II 19
    !• i • • • 11 11 11 i il 111 11 il i 11 i i il 11 i• i il i 11i • il 11 i 11 il	11 i 111. li. i 11 111 j 11 i .I	I
    23  30    7    14    21    28   4
     IUNE I        lULT        I
    no. i - CONTROL


STSU""°2"TEST   PERFORMANCE OF ACTIVATED  SLUDGE SYSTEMS  DURING STUDY PERIOD

                                                 FIGURE 4
HUE - 1969
                                                     15   22

                                                  DECEMBER

-------
of the variation observed in percent removal.  The chronological plot
of the aeration tank outlet dissolved oxygen shows the difficult control
problems that were experienced during the first six weeks of  the study.
During the initial D.O. evaluation tests  (test periods 2 and  3), the
desired D.O. difference between the test  system (No. 2) and the control
system (No. 1) was not achieved due to limited blower capacity.  However,
after installation of the second blower,  the D.O. variation studies per-
formed during test periods 9, 10, 11, and 13 (as shown on Figure 4) in-
dicated that significant differences in D.O. were achieved on the  two
systems; the corresponding effects on phosphate removal can be seen.

The overall aeration tank suspended solids operation during the study
period consisted of maintaining the control system at approximately 2,000
mg/L suspended solids and holding the test system suspended solids levels
below 1,000 mg/L during test period 4 and above 3,500 mg/L in test per-
iod 5.

Only the order-of-magnitude changes in flow can be seen on Figure  4.
The two specific low-flow studies in the  test activated sludge were made
during test periods 6 and 12; the diurnal flow variation study was dur-
ing test period 8; the successful high-flow study was conducted during
period 16, with an unsuccessful attempt during period 7.  This earlier
high-flow test was not successful because severe bulking occurred  in
both activated sludge systems during the week of 15-19 September 1969,
and the primary effluent flow to both systems was reduced in  an effort
to maintain reasonable effluent quality and to correct the bulking situa-
tion.  A similar bulking situation occurred during the week of 25-29
August 1969, and the resulting imposed reduction in primary effluent flow
can be "seen on Figure 4.

The mixing configuration studies took place during test period 15  for
complete mixing, 17 for step aeration, and 19 for contadt stabilization.
The corrective effects on activated sludge phosphate removal  caused by
returning to plug flow on periods 18 and  20 are also seen on  Figure 4.

The overall average performance of both the control and test  systems is
presented in Table 2.  These averages are of reduced significance be-
cause of the wide range of conditions in  the activated sludge system
during the study period.  In order to obtain a reasonable estimate of
the full-scale activated sludge phosphorus removal in the control  sys-
tem at Baltimore, performance data for that portion of the study period
after the initiation of the use of the second blower were averaged.
Therefore, average control system performance for test periods 5 through
15 is also shown on Table 2.

To clarify the presentation of the phosphate removal performance of the
control activated sludge system during this four-month period, a
probability plot is presented in Figure 5.  This was prepared by taking
the observed daily performance and ranking and plotting the values.  The
three observed low values of phosphate removal (on September  9th,  October
7th, and October 21st) were not included  in the probability plot because
operation was not normal on those days, but was deliberately  imposed on
                                21

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                                                   Table 2
                            Average Project Operation and Performance  Conditions
     Parameters
        Flow
N>
        ss
        BOD,
        pH
          Performance
          Conditions
Primary Effluent, mgd
Return Sludge, mgd
Sludge Wasting, mgd

P.E., Total Phosphorus, mgP/L
P.E., Ortho Phosphate, mgP/L
Removal of Total Phosphorus, %

P.E., Suspended Solids, mg/L
Secondary Effluent SS, mg/L
Aeration Tank SS, mg/L
Aeration Tank VSS/SS, %

P.E. Total Carbon, mg/L
Removal of Total Carbon, %

P.E. - BOD5, mg/L
Removal of BOD5, %
BODc Loading, Tb./day/Ib. SS
Production Ibs. SS wasted/lb. BOOC

P.E. - Ammonia N, mg/L
P.E. - Kjeldahl N, mg/L
Removal of Kjeldahl N, %
S.E. Nitrate + Nitrite N, mg/L

Primary Effluent
Secondary Effluent
System No. 1
System No. 2
System No, 1
6/23-12/4/69
8.9
2.0
0.18
11.3
9.3
75
148
11
2,090
73
168
58
177
90
0.29
1.14
23.6
27.8
40
0.75
6.4
7.0
6/23-12/21/69
9.1
2.5
0.20
11.3
9.2
63
139
12
2,030
74
160
57
178
90
0.32
1.10
23.8
28.2
39
0.70
6.3
7.0
8/25-12/4/69
9.1
2.1
0.20
11.4
9.7
82
156
12
2,060
73
153
60
169
91
0.29
1.24
26.4
30.0
42
0.93
6.4
7.0
                    Air Supplied SCFM/gal
                                          1.42
                       1.69
                        1.61

-------
             100
I
to
CO
60
              70
              60
              50
                                          NOTE:  VALUES ARE DAILY AVERAGES

                                               FOR PERIOD 8/11/69 TO 12/10/69
               0.5  1   2     5    10    20  30   40  50  60  70   80    90    95   98  99 99.5

                        PERCENT OF OBSERVATIONS EQUAL TO OR LESS THAN GRAPH VALUE




                        CONTROL   ACTIVATED SLUDGE  SYSTEM


                          PHOSPHORUS  REMOVAL VARIABILITY
                                         FIGURE  5

-------
the control system for test purposes.  More than 60 values went into the
composition of the probability plot, and they indicated that the total
phosphorus removal be less than 73 percent or the ortho-phosphate removal
less than 83 percent only 10 percent of the time.  The 50 percent probability-
of-occurrence values were 86 percent removal to total phosphorus and 93 per-
cent removal of ortho-phosphate.

Figure 6 presents probability plots of the actual ortho-phosphate and
total phosphorus concentrations observed during this four-month period
for both the primary effluent and the final effluent from the control
system.  Again, these plots are of the daily average or composite sample
results and omit the previously mentioned three cases of phosphorus
release.  As indicated on Figure 6, the primary effluent exceeded 15 mg P/L
of total phosphorus and 13.3 mg P/L of ortho-phosphate only 10 percent
of the time.  The secondary effluent from the control system exceeded
3 mg P/L of total phosphorus and 2.2 mg P/L ortho-phosphate only 10 per-
cent of the time.

The phosphorus removals shown in Figure 5 and Table 2 were determined on
a basis of direct subtraction of the secondary effluent concentration
from the primary effluent concentration.  To confirm that this approxima-
tion of the phosphorus removal is realistic, some direct phosphorus
balance computations were done for selected periods and compared with
the indicated phosphorus removal as estimated from the system outlet and
inlet concentrations.  A phosphorus balance is shown in Table 3; the
comparison appears to be adequate, both by pounds of phosphorus removed
between the inlet and outlet and by pounds removed as discharged in
the return sludge system.  The difference between the secondary effluent
total phosphorus and ortho-phosphate is primarily due to the phosphorus
contained in the effluent suspended solids.

As an additional description of the control system performance, a typical
profile of concentrations across the control activated sludge system is
shown in Table 4.  This is one of the 21 different profile studies in-
cluded in Table A-6 in Appendix A.  The particular sample point locations
throughout the activated sludge system are clearly indicated in Table 4.
The changes and different parameters at the seven sampling points distri-
buted across the aeration tank are obvious.  The soluble phosphorus
ranges from approximately 30 mg P/L at the inlet end of the aeration
tank down to less than 1 mg P/L at the outlet end of the aeration tank,
while the total phosphorus (including that in the suspended solids
across the aeration tank) stays essentially the same.  The Kjeldahl ni-
trogen shows a somewhat similar response.  Also, for this particular
profile, soluble magnesium and calcium determinations were made across
the aeration tank.  This profile performance is typical of those ob-
served across the control aeration tank throughout the entire study
period, with the exception that the soluble magnesium release and uptake
are slightly higher than normally observed.  Further details on the
profile observations and data presentation will be introduced while
presenting the individual parameter studies.
                                24

-------
                        2J.O
to
tn
                        16.0
                        14.0
                     _,  12.0
                        10.0
                         8.0
                         6.0
                         4.0
                         2.0
                         0.0
                                     NOTE:  VALUES ARE DAILY AVERAGES
                                           FOR PERIOD 8/11/69 TO 12/14/69
                           0.5 1   2     5    10    20  30  40  50  60  70   80    90    95
                                  PERCENT OF OBSERVATIONS  EQUAL TO OR  LESS THAN GRAPH  VALUE
99  99.5
                            CONTROL ACTIVATED SLUDGE SYSTEM VARIABILITY
                      IN INFLUENT AND EFFLUENT  PHOSPHORUS  CONCENTRATIONS
                                                    FIGURE  6

-------
                                                         Table 3

                                   Mass Balance for Phosphorus Removal  Determination
                                                          Overall  Study Period
Incoming:
  Primary Effluent, Ibs. P

Accounted for:
  Secondary Effluent, Ibs. P
  Waste Activated Sludge, Ibs. P

    Total

Precent Accounted for

Overall Removal of Phosphorus, %
  (inlet to effluent)
                                                   System No.  1
                                                  6/23 - 12/4/69
137,000
                 System  No.  2
               6/23  -  12/21/69
152,000
                   Specific  Four-Day Period
                       (Test Period  12)
                 System No.  1     System  No. 2
                  11/3  - 7/69     11/3 - 7/69
3,900
1,960
33,600
95,200
128,000
94
75
55,800
104,200
160,000
105
73
245
3.270
3,515
91
94
123
1 .805
1,928
99
94

-------
                                       Table 4

                         Typical  Profile Analytical  Results

                            Activated Sludge System No.  1
PE   AT.1
                               AT-2 AT..3 AT-4  AT-5  AT-6  AT-7
                                                   o
                                 Sampling Positions
 SE
     Normal Control System 12/3/69 - 4:00 p.m.,  MLSS = 1850 mg/L,  P/SS = 5.4 percent
D.O., mg/L
pH
BO05,mg/L
Sol. COD, mg/L
Sol. TOC,mg/L
Ortho PO^.mg P/L
Sol.Tot. P.mg P/L
Tot. P,mg P/L
Sol. Tot.KN, mg/L
Tot. KN, mg/L
Sol. Mg, mg/L
Sol. Ca» mg/L
-
6.6
170
215
110
8.7
9.7
_
_
36.0
_
-
0.1
6.6
-
75
55
30.2
33.0
98
29.2
150
17.6
26.5
0.1
6.7
-
70
50
24.4
27.0
97
28.6
156
16.8
27.8
0.3
6.8
-
55
4o
16.3
18.8
98
26.2
154
14.0
26.5
1.0
6.8
-
50
35
5.5
6.2
98
21.6
152
11.0
25.0
3.6
6.8
-
40
30
1.0
1.4
100
18.8
156
8.8
30.0
4.6
6.8
-
35
30
0.5
0.8
98
16.8
148
8.0
24.0
5.2
6.8
-
30
25
0.3
0.7
102
16.0
152
7.6
25.0
                                                    6.5

                                                     90
                                                     55
                                                   46.4
                                                    >50
                                                    520
                                                   27.0
                                                    516
                                                   17.0
                                                   30.0
1.2
6.8
 10
 45
 35
0.3
1
 All  other profile results will  be presented in  a  similar manner.

'Legend;
   PE - Primary Effluent.
   AT-1 to A-6 - Aeration  tank sampling points  located  at respective positions
                 along the length of the aeration  tank.
   RS - Return Sludge.
   SE - Secondary Effluent.
                                          27

-------
                    Specific Parameter Studies

Dissolved Oxygen Variation

A considerable portion of this study (test periods 2, 3, 9, 10, 11, and
13 - eight weeks out of the 26-week total) was devoted to an examination
of the full-scale effect of dissolved oxygen variation in the aeration
tanks.  The first four weeks of dissolved oxygen variation observations
that took place prior to the initiation of the use of the second aeration
blower are of reduced significance because of the severe lack of control
of D.O. in the aeration tank.  For about nine months of the year, operation
of one blower provides adequate aeration for the two activated sludge
systems; however, D.O.-limiting problems during this four-week period
were intensified by the warm summer temperatures and by operating
difficulties in the sludge handling and treatment area that resulted in
uncontrolled abnormally high organic loadings in the primary effluent.
A profile study performed on July 25, 1969, and included in Appendix A,
showed the control system as removing more than 90 percent of the soluble
phosphate, while the test system with low aeration tank D.O. was removing
only about 20 percent.  However, more conclusive comparisons between the
high dissolved oxygen and low dissolved oxygen aeration tank conditions
were observed and will be reported for subsequent dissolved oxygen studies.

     D.O. Response of Both Full-Scale Systems

The remaining four weeks of D.O. variation studies took place when the
analytical monitoring system was operated with a higher degree of refinement
and a more definitive comparison of the two system responses could be made.
A chronological plot of the activated sludge system performance for the
first of these later D.O. variation studies with parallel conditions on
both systems is shown in Figure 7.  The plotted lines represent hourly
observations of the four parameters of ortho-phosphate, aeration tank
outlet dissolved oxygen, pH, and total carbon.  Some brief instrument
outage time is indicated by the gaps in the plots.  The intent of this
study was to lower the outlet aeration tank dissolved oxygen levels grad-
ually until a phosphorus release occurred.  The dissolved oxygen levels
were about equal in both systems reaching a minimum of approximately
2.0 mg/L, at which condition limited phosphorus release were caused in
both secondary effluents, which were higher in No. 2 than No. 1.  The
low D.O. level attained in this one-week study of parallel conditions
in both test and control activated sludge systems was not severe enough
to stimulate a large release of phosphorus.  Also, pH data in Figure 7
indicated a distinct shift in primary effluent pH on 10/16/69 and a sub-
sequent shift in a secondary effluent pH approximately three hours later.

Figure 8 is a plot of the one-week D.O. variation Test No. 2, which in-
volved alternating conditions on both the activated sludge systems and
substantially lower aeration tank dissolved oxygen levels.  The results
are presented in a similar manner to those of Figure 7.  The low D.O.
conditions were first imposed on the control system, showing peak re-
lease condition of about 28 mg P/L of ortho-phosphate with a primary
effluent average concentration of approximately 10 mg P/L.  This was
                                28

-------
15

10
5
0
—

"
—

^-x
\ .,
^ ^
^s

^ m
V-T^./
^y*^.



^•^/^


—.

^--—
^

KJ
•O
      L F G  E N 0
                         200

                         150

                         100

                          50

                           0
                                                      10/14/69
10/15/69
10/16/69
                                                                                                            10/17/69
PRIMARY EFFLUENT      10/13/69
SECONDARY EFFLUENT NO.l - CONTROL
SECONDARY EFFLUENT NO.2 - TEST                            TH*E
       D  O  VARIATION  TEST  NO.l -  PARALLEL CONDITIONS  ON  BOTH  SYSTEMS
                                              FIGURE  7

-------
                          30 ,—
                          20  —
                          10  -
CO
o
                  LU =D X
                          10 ,—
                          5  —
     L F G  E N 0
               PRIMARY EFFLUENT      10/20/69

               SECONDARY  EFFLUENT NO.I - CONTROL

               SECONDARY  EFFLUENT NO.2 - TEST
10/21/69
10/22/69


 TIME
                                     10/23/69
10/24/69
                   D O VARIATION  TEST  NO.2 -  ALTERNATING CONDITIONS ON BOTH  SYSTEMS
                                                             FIGURE  8

-------
followed by low D.O. conditions on the test system that stimulated  an
even higher release, reaching a peak of approximately 33 mg P/L  of  sol-
uble phosphorus in the secondary effluent with little change  in  incoming
primary effluent phosphorus concentration.  During the period of high
phosphorus release of the test system with a low dissolved oxygen level
in the aeration tank, derogatory effects on the total carbon  removal and
the effluent pH were detected.  The phosphorus released in the effluent
above the level in the primary effluent can easily be accounted  for by
observations of the phosphorus in the activated sludge in the systems.
Analysis of the activated sludge systems on 10/17/69 before this partic-
ular study, showed a sludge phosphorus content of 5.3 percent for Sys-
tem No. 1 and 5.9 percent for System No. 2.  Then, on 10/23/69,  after
major releases had taken place on both systems, similar analysis of the
activated sludge solids showed 3.1 and 2.2 percent phosphorus for Sys-
tems No. 1 and No. 2, respectively.  At this time the phosphorus content
in System No. 1 activated sludge was building up to the normal 4 to 5
percent since system phosphorus removal had recovered.

     D.O. and Phosphorus Release Studies on Test System

During test period 11, a D.O. variation study was performed involving
a gradual variation in aeration tank outlet dissolved oxygen  level  to
see if a critical value could be determined at which a system phosphorus
release is initiated.  A chronological plot of the results is presented
in Figure 9.  A phosphorus release was initiated in the test  system
approximately six hours after the reduction of aeration in that  system,
even though the aeration tank dissolved oxygen was still above 2 mg/L in
its downward decline.  Two major releases of phosphorus took  place
in the test system during the test period; however, during the same
period the control system maintained an ortho-phosphate outlet
concentration of 0.3 mg P/L or less.  No conclusive observations can be
made from this brief test as to a critical D.O. level at which a phos-
phorus release is stimulated in the activated sludge process.

The last D.O. variation study was performed during test period 13,  with
the objective of observing how the activated sludge system responded to
rapid changes in dissolved oxygen level.  A plot of the results  of  this
test is shown in Figure 10 and is presented in a format similar  to  that
of previous studies.  Phosphorus releases were stimulated in  the test
system on a daily basis, and as the secondary effluent phosphorus
concentration approached that of the primary effluent, high-level
aeration was resumed in the aeration tank to facilitate a rapid  recovery
of phosphorus removal.  The response in Figure 10 indicates that, repro-
ducibly, a significant phosphorus release can be stimulated within  six
hours of lowering the level of aeration and that complete recovery  can
be attained within approximately 10 hours of restoring high-level aeration
to the system.  It should be emphasized that the final effluent  samples
represent an approximate eight-hour lag compared to the primary  effluent
and the secondary effluent observations represent about a two-hour  lag
compared to those taken at the end of the aeration tank.  During the
study, the monitoring system was operated in the three-point  mode,  so
                                 31

-------
                          20

                          15


                          10


                           5

                           0
CO
KJ
                          10
                         6.0
                         6.0
                      _,  200
                      \
                      C9

                      *  150
                      O

                      5  100
                      CJ


                      *   50
                      CD
                      t—
                           0
      L  F G [  N  D
                 PRIMHRY EFFLUENT     10/27/69
                 SECONDARY  EFFLUENT  NO I  -  CONTROL

                 SECONDARY  EFFLUENT  NO.2  -  TEST
-v'
              V-
 10/26/69
10/29/69
               TIME
                                        10/30/69
10/31/69
                            D  O VARIATION  TEST  NO.3 - GRADUAL  CHANGE  ON  TEST SYSTEM
                                                                 FIGURE 9

-------
       3°


       25


       20
  I CD   10 l~
  i -»   lu
        5  -
I
CJ
CO
I
8.0


7.0


6.0
300


250


200


150


100


 50

 0
                                                *-.'
                                                                 *  *
              11/10/69
                        11/11/69
11/12/69
11/13/69
         LEGEND

         '	PRIMARY EFFLUENT

         	 SECONDARY  EFFLUENT #1-CONTROL

         ^— SECONDARY  EFFLUENT #2-TEST
                                                                              11/14/69
                                                                         TIME
                                                                                       11/15/69
                                                                                                             11/16/69
                                                                                                                             11/17/69
                                                                                                                                             11/16/69
                                       DO  VARATION TEST  NO.4 - RAPID CHANGE  ON TEST SYSTEM

                                                                    FIGURE   10

-------
that visual interpretation of the instrument analog  chart output  per-
mitted immediate assessment of the final effluent phosphorus  concentra-
tion and precise adjustment of aeration when the desired conditions were
reached in the activated sludge system.

The performance of the control system during the study presented  in
Figure 10 was similar to that shown in Figure 9 for  the first  six days,
with the effluent concentration of ortho-phosphate being equal or less
than 0.3 mg P/L.  This performance was not impaired  by the  fact that,
when changing the aeration rate from approximately 8,500 scfm (in each
aeration tank) to a phosphorus release test condition of 13,000 scfm in
Aeration Tank No. 1 and 4,500 scfm in Aeration Tank  No. 2,  the flow
through Aeration Tank No. 1 was increased by 10 percent and the flow
to Aeration Tank No. 2 was decreased by approximately 10 percent.

Some impairment in phosphorus removal in the control system was observed
on 11/17 and 11/18 (Figure 10).  The only abnormal operating  condition
during that time was an unusually high sludge wasting rate early  in the
morning on 11/17 and again early in the afternoon on 11/17.   The  high
wasting rate (approximately 10 to 15 times normal) caused aeration tank
mixed liquor suspended solids concentration to drop  from approximately
2,100 to 1,600 mg/L.  During this same period, there was some  excessive
wasting on System 2; however, the aeration tank suspended solids  showed
only a 200 mg/L decrease.  An expanded chronological plot of  the  phos-
phorus data presented in Figure 10 showing the actual data points  can be
seen in Appendix B.

The association of impairment of carbon removal with low D.O.  phosphorus
release is not extremely obvious or conclusive.  The soluble  carbon
content is constantly varying both in primary and secondary effluent,
and since there are always significant carbon levels in the final  efflu-
ent, effects caused by process changes are frequently overshadowed by
wastewater variations.  At normal operating conditions, both  test  and
control systems produced essentially identical carbon removal  perform-
ance.  Therefore, based on the assumption that the control system ef-
fluent concentrations are valid comparison bases for the test  system
potential removal at any specific time, Table 5 presents one  approach
of associating carbon performance impairment with phosphorus  releases
caused by a low D.O. condition.  The carbon and phosphorus final  efflu-
ent differences between the two systems are shown for three cases,
all of which closely associate carbon effects with phosphorus  releases
at these apparently oxygen limiting conditions.  In  all three cases,
as soon as the secondary effluent phosphate concentration increased
in the test system, the total carbon concentration increased  too,  with
respect to the test system.  Although impairment in  carbon removal was
not as significant as that for phosphorus removal, it still was observ-
able.

     D.O. - ORP Relationships

Figure 11 presents the limited Oxidation-Reduction Potentional (ORP) obser-
vations that took place during test period 13.  The  ORP is reported in
terms of Eft, millivolts referenced to hydrogen electrode.  The instru-
ment system used to measure the data in Figure 11 was a silver-silver

                                34

-------
I
w
Oi
    ^   500
    — c/o
    £^ 400
    UJ <=>
    £± 300
    0	1
    x± 200
           It   tit    t  I  t   t
                I
                                           tt
                I
                          AIR SUPPLY
                          CHANGES
    CJ
    LLJ
    CO
25
20
15

10
 5

 0
                                                       A   :
                  11/12/69
1/13/69
                                 1/14/69
1/15/69

 TIME
11/16/69
11/17/69
                       TEST  ACTIVATED  SLUDGE   SYSTEM   OUTLET
                           ORP,  DO,   AND  ORTHO   PHOSPHATE
                                           FIGURE 11
1/18/69

-------
chloride electrode system.  A tabulation of the average ORP observations
made on the test system is presented in Appendix A.  Figure 11 presents
the data for the test system (No. 2) and also includes the time  and  di-
rection of air supply changes to Aeration Tank No. 2, which are  tabulated
in Appendix A.  The ORP and D.O. observations are directly correlatable
because they were taken at the same point at the same time; however,
the secondary effluent soluble ortho-phosphate concentration has  about
a two-hour delay due to flow time through the final clarifier.   During
the D.O. variation test involving rapid changes shown (in Figure  11),
the responses of D.O. and ORP are considerably different.  In the obser-
vation made on 11/14, the D.O. dropped from approximately 6.0 to  0.4 mg/L,
and for the same period the ORP dropped only from 485 to 425 millivolts.
As the D.O. dropped from 0.4 mg/L down to 0 and the phosphate release
proceeded, the ORP dropped all the way down to about 150 millivolts.
In general, the observations presented in Figure 11 show that as  the
D.O. dropped from 4.0 to 1.0 mg/L, the ORP dropped approximately  70  mil-
livolts to the 350-450 millivolt range, but when the D.O. increased  from
1 mg/L to 4 mg/L the ORP showed a corresponding increase of from approxi-
mately 110 millivolts to the 450-500 millivolt range.

     Effect of D.O. Changes on Phosphorus Concentration

Further observations on the lack of correlation between phosphorus re-
moval and the level of D.O. (above oxygen-limiting conditions) in the
aeration tank are shown in Table 6.  This table presents limited  informa-
tion summarized from the complete profile listed in Appendix A,  showing
only the dissolved oxygen, the pH, and the ortho-phosphate levels at dif-
ferent sampling points across the activated sludge system.  In each  of
the profiles listed, the estimated point of maximum drop in phosphate level
and the approximate point of most rapid increase in dissolved oxygen level
are designated.  In the profiles listed on top of Table 6, the rapid phos-
phate removal point occurs before the rapid D.O. increase point.   Proceed-
ing down Table 6, the most rapid removal of phosphate occurs after the
D.O. has increased to significant levels; the 8/27/69 profile shows  that
the most rapid phosphate removal took place between the end of the aera-
tion tank and the outlet of the final clarifier.

At the bottom of Table 6 are profile data taken from the test aeration
tank at times of ortho-phosphate release and low dissolved oxygen level.
The apparent effect is one where the initial phosphate release that  oc-
curs at the beginning of the tank is maintained throughout the system.
This compares to the normal condition, where an initial release  takes
place before the rapid uptake of soluble phosphorus in the latter part
of the system.  The pH values given on Table 6 show a range of secondary
effluent pH levels from 6.8 to 7.3.  In all cases, there is an increase
of pH across the plug flow system as aeration takes place.

     Effect of D.O. on Batch Removal

As a further confirmation that a specific level of D.O.  (in the  aeration
tank) is not as critical for phosphorus removal as is maintaining aero-
bic conditions, a limited laboratory-scale batch phosphate uptake ex-
periment was performed, and the results are shown in Figure 12.   These

                                36

-------
                                                Table 5
                      Association of Low Dissolved  Oxygen  Phosphate  Release with
                                        Reduced Carbon  Removal
          Difference between Test and Control  Secondary Effluent  Orthophosphate and Total Carbon
            Observations (Monitoring Results Concentration Difference, mgP/L and mgC/L)
Case 1
Time
10/27/69
1700
1900
2000
2200
2300
10/27/69
0000
0100
0200
0300
0400
0500
0700
0800
0900
1100
1200
1300
1400
1500
1600
1700
P2-P1

No. 2 Air
0.2
0.1
0.8
1.3

3.3
4.9
7.4
9.7
12.7
14.9
18.9
No. 2 Air
19.7
15.8
11.5
8.1
5.2
3.1
1.8
0.4
C2"cl

Reduced
0
0
3
5

5
10
—
5
0
5
10
Restored
10
10
10
5
5
10
0
0
Case 2
Time
11/11/69
1600
1900
2100
2200
2300
11/12/69
0000
0100
0200
0400
0600
0800
1000
1200
1400
P2-P,

No. 2 Air
0
0.1
4.6
9.0

10.1
No. 2 Air
16.9
13.7
9.1
4.8
2.0
0.6
0.1
crc,

Reduced
0
5
3
5

0
Restored
10
5
10
5
5
0
0
                                                                           Time
                                                                          11/1A/69

                                                                           2000
                                                                           2200

                                                                          11/15/69
                                                                                     Case 3
                                                                         P2-P,
                                                 C2-Cj
                                                                          No.  2  Air Reduced
                                                                            0             0
0000
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1900
0
1.9
5.7
10.9
15.3
20.3
23.8
No. 2 Air
25.8
23.5
21.5
15.6
10.5
6.7
3.6
2.0
0.8
0.2
0
0
15
15
15
25
20
35
Restored
25
40
30
45
—
20
10
-5
5
0
0
NOTE:  At normal operating conditions on both systems,  there is  no significant difference in secondary
       effluent orthophosphate or total carbon between  the two systems.

-------
                                Table 6

      Relationship Between Soluble Phosphorus and Dissolved Oxygen
                     in the Activated Sludge System
                       PE
       Sampling  Position  for  Profile  Study

AT1    AT2    AT3    AT4    AJ_5    AT6   AT?   RS
                                                                                 SE
9/17/69-Test
Ortho P, mgP/L
D.O. , mg/L
PH
1 1/18/69-Control
Sol .Tot.P mgP/L
D.O. , mg/L
PH
12/3/69-Control
Ortho P, mgP/L
D.O., mg/L
PH
12/10/69- Test
Sol .Tot.P, mgP/L
D.O.,mg/L
PH
8/27/69-Control
Ortho P, mgP/L
D.O. , mg/L
PH
9/3/69-Control (1
Ortho P, mgP/L
D.O. mg/L
PH
10/23/69-Test
Ortho P, mg /L
D.O. mg/L
PH
10/21/69-Control
Ortho P, mgP/L
D.O. mg/L
PH

8.7
-
6.5

8.0
-
6.3

8.7
-
6.6

10.8
-
6.3

4.8
-
6.4

10.2
0.0
6.8

27.5
0.0
-

30.2
0.0
6.6

30.0
0.0
6.5

50.8
0.0
6.6

1.3 0.6 o.;

5 0.2 0.3 0
0.1 1.2 J 3.6 5.4 5.6 6
6.9 6.9 i 6.9 6.9 7.0 7

17.7 6.8 2.C
0.3 1.0 2.C
- - -

24.4 16.3 5.5
0.1 0.3 1.C
6.7 6.8 6.E

29.4 18.0 8.1-
0.1 0.3 }.L
6.6 6.7 6.7


) | 1.1 0.5 0
) . 4.5 5.5 6
1

; 1.0 0.5 o
) 3.6 4.6 5
\ 6.8 6.8 6

\ \ 4.2 3.6
^ , 4.7 5.7 6
' I 6.7 6.8 6

14.1 | 13.9 13.7 - 12
- i - 6.0 - - 4
- ! - 6.8 - 6

.2
.6
.0

.3
.0
—

.3
.2
.8

-
.4
.8

.5
.9
.9

20.6
-
6.6

15.4
-
-

46.4
-
6.5

50.0
-
6.4

78.0
-
6.8

0.3
1.6
7.2

0.6
2.5
7.0

0.3
1.2
6.8

1.4
0.5
6.9

0.5
1.3
7-1
:00 AM from Monitoring Data)
6.5
-
6.4

8.5
-
6.6
(5:00 AM
10.8
-
6.4
30.4
0.0
6.8

8.9
0.0
6.1
from Mon
38.0
0.0
6.7
26. y
0.5
' - l - 20
1 ,
' - i - 3
6.7 - i - 6


12.7 11.0 10.0 9.3 10.8 11
0.1
0
6.9 - 6
itoring Data)

61.0 - 40
0.1
0
6.7 - 6
.5
.3
.7

.8
.3
.9

.0
.4
.9
40.2

6.7

25.5
-
6.7

62.5
_
6.6
0.9
0.2
6.8

10.8
0.1
6.9

21.7
0.1
7.2
Note:  "I" designates maximum P removal  and "i" designates maximum D.O. increase

                                    38

-------
            10
             5  -
           PERFORMED  12/29/69
           FOR EACH TEST - 1^ PRIMARY EFFLUENT
                       30f. RETURN SLUDGE
            10
         to
         GO
                     1
1
                   i
              0
          100
200
                            BATCH AERATION TIME - Mlh'JTCS
      L t G E N D
         .NORMAL - UNLIMITED AERATION
          TEST - D 0 CONTROLLED  BETWEEN 0.4 - 0.8  MG/L
300
EFFECT OF DISSOLVED OXYGEN ON  LABORATORY -SCALE
                         BATCH AERATION

                             FIGURE   12
                                —39—

-------
tests were performed with full-scale constrol System No.  1 activated
sludge and primary effluent at Baltimore.  One system had a  dissolved
oxygen detection and control system that maintained the D.O.  level
between 0.4 and 0.8 mg/L.  The results in Figure 12 indicate that both
systems were aerated continuously for the first 20 minutes,  after which
the D.O. controller was in operation.  There was no significant  difference
in the phosphate removal of the two systems.

Variation in Suspended Solids

The effect of aeration tank suspended solids on phosphorus removal  was
studied on the System No. 2 in test periods 4 and 5.  During these  tests,
the suspended solids level in the test aeration tank range from  590 to
3,990 mg/L, while the control system was maintained at about 2,000  mg/L.
Figure 13 presents the monitoring results of the high aeration tanks
suspended solids test. The gap in the analyses represents the Labor Day
weekend when no data were collected.  The ortho-phosphate removal in  both
systems was consistently good through the observation period, and no  signi-
ficant differences were observed between the test and the control systems.
Bulking was experienced in the test system only during the period of
8/29 to 9/4 and the sludge volume index  (SVI) ranged from 200 to 300
in the test system and from 100 to 150 in the control system.  During
much of test period 4, the second air blower was in use to assure main-
tenance of adequate D.O. levels in the test aeration tank.

A plot of the observations during the low aeration tank suspended solids
study is shown in Figure 14.  A sustained period of operation at suspended
solids levels below 1,000 mg/L was not acheived.  However, above this
level of solids, no impairment of phosphorus removal was  experienced.
Some phosphorus releases were experienced in the test shown  in Figure 14.
The first release was experienced on 8/7 and was caused by a low dissolved
oxygen condition in both aeration tanks.  Another release was caused  on
8/12 in the test system by a low D.O. level.  On 8/14 another phosphorus
release occurred in the test system, but at this time, the second blower
was put into operation to be certain that a low D.O. condition was  not
causing the release condition.  During this time, the aeration tank
suspended solids reached a minimum of 588 mg/L.  However, it is  uncer-
tain whether this phosphorus release was caused by the low level of
suspended solids or by rapid wasting of  the mixed liquor  suspended
solids which had taken place during the previous 24 hours.   Then on
8/18 and 8/19, phosphorus releases were observed on both  test and con-
trol systems.  The test system minimum suspended solids reached  at
this time was 692 mg/L.  However, immediately preceding these last
releases, significant levels of solids reduction had taken place in
both the test and control systems, to 500-700 mg/L over a 20-hour period.
In these cases, when the abnormally high wasting rate was returned  to
normal, gradual recovery of phosphate removal was achieved.

During the overall project study period, other observations  were made on
the circumstantial connection between abnormally high levels of  sludge
wasting and a subsequent phosphorus release in the activated sludge
system.  One case described earlier was  that depicted on  Figure  10

                                40

-------
                      15
                      10
                       5
                       0

                      10
                       0

                      8.0
                      7.0
                      6.0
                                V
\  /x
v^  '
LEGEND
           250

        S  200
        if
        z  150
        O
        CD
        5  100
        _J
        5   50
        I—
            0
PRIMARY  EFFLUENT
SECONDARY EFFLUENT NO.1  - CONTROL
SECONDARY EFFLUENT NO.2  - TEST
                                                                 30
                                                                        31
                                                                                                   V
                                          AUGUST 1969 - (DAYS)                          SEPTEMBER 1969 - (DAYS)
                                        HIGH  AERATION TANK  SUSPENDED SOLIDS  TEST
                                                                 FIGURE 13

-------
                 15



              — 10
            !±S   10
I
^
KJ
 LEGEND
200
150
100
50
0
-
-




r*
j
L 	
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:^

^-
p w

\/
^=*











V
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w
V
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^^ ^^

/^








-
-

          PRINARY EFFLUENT 2345


          SECONDARY EFFLUENT NO I - CONTROL


          SECONDARY EFFLUENT NO 2 - TEST
                                                      10   11
                                                              12
                                                                  13   U
                                                                              16
                                                                                       18   19
                                                                                              20
                                                                                                  2]   22
                                                                                                          23
                                                                                                              24
             AUGUST 1969 - (DAYS)

AERATION TANK  SUSPENDED  SOLIDS  TEST

                  FIGURE 14

-------
concerning D.O.  studies, where  an unexpected phosphorus  release  occurred
in the control system,  and previous excessive sludge wasting was the  only
condition that could be associated with  the phosphorus release.   On
December 1, 1969, another phosphorus release occurred in the control
system at a time of high D.O. in the aeration tank; the  suspended solids
level had been reduced  from  2,050 to 1,750 mg/L because  of  the higher
sludge wasting rate over the preceding 8-hour period.  A final observa-
tion on the association of diminished phosphate removal  associated with
a high wasting was made in February 1970.  Severe bulking had taken over
the activated sludge system, and the operators wasted excess sludge over
a short period of time, thus reducing the aeration tank  suspended solids
from above 2,000 down to about  1,000 mg/L.  Although only limited phos-
phorus monitoring data  were  available in February 1970,  results  indicated
that it took approximately one  week for  the system to recover to a high
level of phosphate removal.

Profile observation on  samples  taken at  different points in the  activated
sludge system while operating at different aeration tank suspended solid
levels are listed in Table 7.   While the activated sludge system was
removing a high  degree  of phosphorus, the initial release of phosphorus
at the beginning of the aeration tank increased with suspended solids,
and the rate of  phosphorus removal likewise increased.   Additional ob-
servations showing this same effect in batch tests are presented in
Figure 15.  The  batch tests were performed simultaneously.  The  time
required to reduce the  inlet concentration to a soluble  ortho-phosphate
level equal to or less  than 0.4 mg P/L is related to the suspended
solids, and is not necessarily  a function of the inlet wastewater char-
acteristics.  Complete  observations associated with Figure  15 are pre-
sented in Appendix A and include a thorough characterization as  to the
phosphorus, nitrogen, and carbon changes during these batch uptake tests.

The last factor  related to suspended solids concentration was the inven-
tory of solids in the final  clarifier.   The Baltimore activated  sludge
secondary clarifiers normally operate with a sludge depth of less than
1 foot in the bottom of the 13-foot side water depth.  In one experi-
ment, the return sludge recycle was dropped from the normal 25 percent to
10 percent.  This action was unsuccessful in raising the final clarifier
sludge depth above 2 feet, because the sludge condition  was such that an
increased underflow suspended solids concentration permitted the return
of almost the same amount of suspended solids per unit time.  However, at
the two times when bulking was  experienced in the test system and the
secondary clarifier sludge blanket was within 2 feet of  the overflow
level (on 8/27 and 9/19), no reduction in phosphorus removal was experi-
enced.

The only occasion where a significant phosphate release  was observed  to
have taken place in the final clarifier was during a condition where
the sludge collection mechanism was accidentally shut off for a  period
of two days (9/18 - 9/20) .  The resulting reduction in aeration  tank
suspended solids stimulated the operators to investigate and restore
the clarifier to normal operation.  Since this occurred  on  a weekend,
continuous monitoring data for  phosphorus release was not available,
although limited grab samples indicated  that a significant  release did
take place.

                                43

-------
               Table 7
Summary of Profile Results at Various
       Suspended Solids Levels

Low Solids - 8/13/69 Daily Averages
   PE
ATI
AT2
AT3
RS
SE
SS, mg/L
Ortho PO/4, mgP/L
Total P, mgP/L
Sol . Total C, mg/L
Ammonia N, mg/L
i/j_|j_l_l 1.1 _ , /i
Kje 1 danl N , mg/L
Nl 4- •- -* +• A J_ kl t *• •• i *-** mnhJ /I
it rate + Nitrite, mgN/L
Df\ _._ /i
.U . , mg/L
pH
Flow, mgd


SS, mg/L
Ortho POjL, mP/L
f,— A. _ 1 D M»*D/I
lotal r, mgr/L
Sol . Total C, mg/L
Ammonia N, mg/L
Nitrate + Nitrite, mgN/L
Drt .__ /i
. U . , mg/L
pH
F 1 ow , mgd
112
7-7
11.0
115
21*. 1*


OA7
.U/


6.1.
6.7
High Sol
PE
11*1*
8.1


190
22.1*
0.6


6.5
5.5
1,1*00 1
22.0
7.0
720
21 .8
i nQ
1 (Jo
01
• 5
01
. 1
6.7
8.6
ids - 8/29/69
ATI
3,730 3
1*5.8
1 in
1 /U
100
17.2
1.0
On
. U
6.7
9.1
,360
12.9
70
85
18.0
1A.O
(Jf.
01
. 1
0 ft
L .0
6.9
8.6
Daily
AT2
,81*0
13.7
i £o
1 Ot
95
15.2
1.1
31
• i
6.8
9.1
1,51*0
1.9
71*
80
16.5
1 1 A
1 1 U
00
. /
31
o
7.0
8.6
Averages
AT3
3,760
2.2
1 CO
i :>*•
80
12.6
2.3
5ft
.u
6.8
9.1
6,51*0
21*. 1
200
105
22.5






6.8
1-9

RS
8,860
^7


100
16.9
1.1*


6.6
3.6
12
0.3
1.0
70
16.3


01
, )
21
. )
7.1
6.5

SE
5
0.2
1 r
1 .5
65
10.1
2.3
Of
.0
7.1
5.1*

-------
     30
                       TESTS PERFORMED SIMULTANEOUSLY WITH  ALL MIXTURE
                       COMPONENTS FROM FULL  SCALE SYSTEM NO  1
                                 10:00 AM
                                           INITIAL
10/1/69

     MIXTURE
                          PE   RS    SE
                       A)- 5L   5L
                        )- 5 L  2 . 9 L  2. 1 L
                        )- 5 L  1 . 4 L  3. 6 L
TOT.SS  SOL. TOT P
 MG L
 3100
 1850
                 1050
                         MGP/L
                         12.0
                         9.0
         6.8
TIME FOR SOLUBLE
TOT P TO REACH
0.4 MG/L  MIN.
     40
     60
    I 10
                            60
                         120
                              80
                              TIME - MINUTES
LABORATORY BATCH  TESTS  AT VARYING  SOLIDS  LEVELS
                              FIGURE 15
                               —45—

-------
Variations In System Flow

The effect of hydraulic loading  on  the  conventional  activated sludge
system at Baltimore was evaluated by  studying  the  operating results
during five of the test periods  when  the  flow  was  different than the
design flow.  The average operating conditions and system performance
for three different flow conditions are presented  in Table 8, and chron-
ological plots for a portion of  the low-flow,  diurnal variation, and
high-flow studies are shown in Figures  16,  17,  and 18.

     Low-Flow Studies
The low-flow studies were performed during  test periods  6  and  12,  when
the aeration tank detention time was approximately  twice that  of normal
operation.  No impairment in phosphorus removal was  observed during
either of these studies.  Figure 16 shows a chronological  monitoring
data plot of a 4-day portion of test period 6.  The  ortho-phosphate
release observed in the control system on 9/9/69 was  caused by a low D.O.
condition in the aeration tank.  The slight reduction of phosphorus
removal in the test system during the release in the  control system indi-
cated the possibility of limited leakage between the  two systems.   It is
also interesting to note that the pH levels of both  secondary  effluents
were quite similar and not specifically affected by  the  added  aeration
time.  The phosphorus removal in either system was not impaired when the
secondary pH dropped to the 6.6 level.  A typical diurnal  change of
primary effluent ortho-phosphate concentration can be seen in  Figure 16.
From this table, it can be seen that the highest incoming  phosphate con-
centrations were experienced consistently in the last 8  hours  of each
day.

     Diurnal Flow Variation

Due to the current unit process arrangement at the Baltimore Back  River
Wastewater Treatment, wastewater flow to the activated sludge  portion
is generally maintained at a constant rate, with less than 10  percent
variation over any daily period.  A diurnal flow variation study was set
up during test period 8 when the flow was varied on  daily  basis from
3 to 10 mgd.   This flow variation program was continued  for a  eleven-day
period, as previously shown in Figure 4.  The continuous monitoring re-
sults for a 3-day portion of test period 8  are shown  in  Figure 17.   Dur-
ing this particular study, the monitoring system was  operated  on a 40-
minute sampling cycle so that a reasonably  continuous record of perform-
ance was achieved with 36 observations per  day at each sampling point.
When the dissolved oxygen level in the aeration tank was not limiting,  a
high degree of phosphorus removal was obtained on both the control and
test systems.   Some difficulties were experienced in  maintaining a con-
stant flow on the control system, while accomplishing the  desired  flow
variation on the test system.  These difficulties were due to  the  re-
quirement for cumbersome manual adjustments and correction for each flow
change.
                                46

-------
                                        Table 8
                      Average Operating Conditions and Performance
                                At Different Flow Rates
Flow   Primary Effluent (P.E.), mgd
       Return Sludge, mgd
       Sludge Wasting, mgd

DT     Detention Time in Aeration, hr.

P      P.E. Total Phosphorus, mgP/L
       P.E. Ortho Phosphate, mgP/L
       Removal of Total Phosphorus, %

SS     P.E. Suspended Solids, mg/L
       Secondary Effluent SS, mg/L
       Aeration Tank SS, mg/L
       Aeration Tank VSS/SS, %

C      P.E. Total Carbon, mg/L
       Removal of Total Carbon, %

BODc   P.E. BODc, mg/L
       Removal of BOD5, %
       BODj Loading, Ib/day/lb SS

N      P.E. Ammonia N, mg/L
       P.E. Kjeldahl N, mg/L
       Removal of Kjeldahl N, %
       S.E. Nitrate + Nitrite N, mg/L

pH     Primary Effluent
       Secondary Effluent
                                          Low Flow
                                        System No. 2
                                        9/6-9/13/69
         Diurnal  Variation
           System No.  2
           9/30-10/12/69
              High Flow
            System No.  2
            12/6-12/11/69
4.7
1.5
0.18
10.0
13.2
8.0
86
173
5
2,230
68
113
62
179
85
0.14
17.7
23.9
67
3.0
6.5
6.8
2.8-9.5
2.0
0.16
13. 0-5. 4
11.8
9.5
89
171
7
1,880
71
139
7T
132
90
0.14
23-9
28.4
40
1.3
6.4
7.0
19.3
4.35
0.30
2.3
10.6
9.0
88
102
10
2,160
77
156
77
178
90
0.61
29.5
31.9
37
0.7
6.4
6.9
Air Supplied SCFM/gal
3.42
2.68
1.15

-------
                          10
                           5

                           0
                          15

                          10

                           5

                           0

00
                          8.0
                          7.0
                          6.0
      LEGEND
                           o
                 PRIMARY EFFLUENT      9/8/69
                 SECONDARY EFFLUENT NO I  - CONTROL
                 SECONDARY EFF LUENT NO 2  - TEST
TIME
                                                  LOW FLOW  OPERATION  TEST
                                                               FIGURE  16

-------
LEGEND
         FRIDJY 10/4/69
PRIMARY EFFLUENT
SECOND*RY EFFLUENT NO.I   CONTROL
SECONMRY EFFLUENT NO.2   TEST
                                                                  SUNDAY 10/6/69
                                      DIURNAL FLOW  VARIATION  TEST
                                      FIGURE  17
                                     •49—

-------
Oi
o
                       10 r AERATION

                            OUTLET
                      600


                      500


                      400

                      300
-


AERATION
TANK OUTLET" — '
*+S* 	 ^



^^"
"
-
 L F C f N 0
                      7.01	-u;^—»5=««i»^*!rT^5=^rrTT
                      6 0 USECONDARY EFF^f-	f	f        1	*     T
                        L.ffilM»RY EFF.-^l         I          I          I         I
                      200




                      100




                       0
         PRIMARY EFFLUENT

         SECONDARY EFFLUENT NO 2 - TEST


                 TEST   ACTIVATED  SLUDGE   SYSTEM   OPERATED   AT   HIGH   FLOW

                                                    FIGURE  18
PRIMARY
EFFLUENT—^
- SECONDARY
EFFLUENT-^
12 5 69
,~s\-
**
12/6 69
\__ X*
^ ~+
12, 7 69
V-
• *
128 69
*» J*
— *— —
129 69
*»^ f.
•^•^
12/10 69
^* *
• — *""
12 II 69
* 	
•^M

TIME

-------
The ortho-phosphate monitoring data in Figure 17 indicated extremely
good removal on both systems.  On 10/5, the average secondary effluent
ortho-phosphate concentration was 0.2 and 0.1 mg P/L for  the control  and
test systems, respectively.  With an average primary effluent feed  con-
centration of 9.4 mg/L, these values represent ortho-phosphate removal
of more than 97 percent.

Additional monitoring parameters are shown in Figure 17.  Since the
average loading and aeration time in the test system is considerably
lower than those in the control system, the total carbon  and COD removals
are slightly higher.  The primary effluent COD and total  carbon removals
show a similar variation with time.  The inlet primary effluent data
show considerable variation in ammonia concentrations with time.  In
particular, on 10/5 in a one-hour period, the ammonia level showed  a
rapid increase from approximately 20 mg N/L to 38 mg N/L, and the cor-
responding delayed effect on the ammonia level in the final effluent
can be seen.  During the period of observation, the test  system had a
considerably higher effluent combined nitrite-nitrate concentration and
this difference corresponds to the lower secondary effluent ammonia lev-
els observed in the test system.  This visual comparison  of actual
monitoring data demonstrates the apparent independence between primary
effluent phosphorus, nitrogen, and total carbon levels.   The most signi-
ficant nitrite-nitrate levels in the activated sludge secondary ef-
fluent were observed when low-flow experiments were being conducted;
however, the effluent combined nitrate-nitrite concentration was never
observed to be above 6.0 mg N/L.

      High-Flow Studies

Two high-flow experiments were conducted during test periods 7 and  16.
Test period 7 was unsuccessful because a bulking activated sludge condi-
tion took place requiring corrective measures.  Also, during test period 7
only one clarifier was used with the Aeration Tank No. 2.  The secondary
clarifiers were designed for an overflow rate of 1,000 gpd/sq.ft. in-
cluding return sludge.  Operating experience demonstrated that at normal
sludge conditions, rising secondary clarifier sludge blanket problems
were experienced if the primary effluent flow to each system was raised
above 12 mgd.  Therefore, to assess the phosphorus removal at a high-
flow condition during test period 16, the test Aeration Tank No. 2 was
used in conjunction with both final clarifiers.

Figure 18 shows the results of the high-flow experimentation.  With flow
levels above the 10 mgd design value, phosphorus removal  was good,  pro-
vided that the aeration tank dissolved oxygen was maintained at an  ade-
quate level.  For an eight-hour period on 12/7 the aeration tank deten-
tion time was 2.1 hours (while the primary effluent flow  was up to  24.8
mgd for one-half of the system), and the activated sludge loading was
approximately 0.67 Ib BODc/lb SS/day.  However, at this high flow rate,
even through the sludge volume index was in the normal the 150-175  range,
                                 51

-------
sludge blanket rising difficulties were experienced in the final  clari-
fiers and the flow had to be reduced to 20 mgd  (double the design of
flow).   Observation of the total carbon COD and BOD removals during  test
period 16 did not indicate serious degradation or downward trends in
effluent quality.  A profile study (Table 8) made 10 December  1969 dur-
ing the high-flow study, indicated the capacity of the system  for higher
flows.

Variations in Mixing Configuration

The study of effects of variations in mixing configuration included  such
deviations from conventional activated sludge plug flow as modifications
toward complete mixing, toward step aeration, and toward contact
stabilization.  The detention time response of the aeration tanks at
these different mixing configurations to a slug introduction of tracer
was previously presented in Figure 3.  All tracer studies performed  in
this study and in previous work at the Baltimore activated sludge system
showed that the aeration tank closely approached theoretical modal
detention times.  At normal design operation, the aeration tank tracer
response approached that expected of plug flow, and was somewhat  better
than anticipated for six completely-mixed tanks in series.  For this
project, each deviation from normal plug-flow operating conditions was
studied for approximately one week, and at the termination of  each study,
the system was returned to plug flow to assure prompt return to normal
phosphorus removal operation.

     Complete Mixing

A modification to simulate complete mixing was achieved by pumping 7 mgd
of the mixed liquor from the end of the test aeration tank back to the
beginning of the tank.  This minor modification was unsatisfactory in
achieving complete mixing, but did represent some deviation from  normal
plug flow operation.  A plot of the monitoring data for this test is pre-
sented in Figure 19.  The control system was operated at normal conditions,
while the modification toward complete mixing was made on the  test system.
As can be seen on Figure 19, some automatic instrumentation problems
were experienced, which limited the monitoring results.  Some  phosphorus
release situations were experienced, but since they occurred on both
the test and control systems, no conclusive statements could be made
concerning the effect of this modification.  These partial phosphorus
releases occurred even though the D.O. was sufficiently high not  to be
a limiting factor for phosphorus removal.  As stated previously,  excess
sludge wasting activity was high on November 30 and December 1 for both
systems and appears to have stimulated this release.  However, on Decem-
ber 2, a low-flow condition in both systems was caused by necessary
treatment plant repairs upstream in the system.  This low-flow apparently
stimulated the recovery of a high level of phosphorus removal  in  both
systems.
                                52

-------
                        STJRT MIXING PUNP
                                                                                                              STOP NIXING PIMP    STOP SYSTEM #1 OPERATION
15
10
5
0
\
^'
v_
^
A/ '
«
^
s
^ 1
1
Oi
to
                    300

                E_,  200
                •*: -^

                ^i  100
                i—
                °    0
12/1/69

 TINE
                                                                                       12/2/69
                                                                                                   12/3/69
12/4/69
12/5/69
t E G E K D        11/27/69    |   11/26/69       11/29/69       11/30/69
	  P«IN»«Y EFFLUENT                '
_____—_  SECONHHT EFFLUENT NO. 1 - U«TIOL
—m—  SECONDLY EFFLUENT NO.2 - TEST

FLOW  CONFIGURATION  TEST  NO.l  - MODIFICATION  OF  PLUG FLOW  TOWARD  COMPLETE  MIXING

                                                             FIGURE  19

-------
     Step Aeration

A modification toward step aeration was achieved during  test period  17
by introducing approximately 7 mgd of primary effluent at  the normal
inlet and an additional 7 mgd at the mid-point in Aeration Tank No.  2.
Both final clarifiers were operated with these test aeration tanks dur-
ing test period 17; thus, no control comparison was available.  The
modification toward step aeration was started-up at 1:00 a.m. on  12-12-69.
As indicated by the monitoring results plotted on Figure 20, an impaired
condition of phosphorus removal in the activated sludge  system began ap-
proximately two days after the start-up of step aeration operations  and
continued during the remainder of the test.  When the system was  returned
to plug flow, total recovery was achieved.  During this  study, the aera-
tion tank D.O. was above the limiting range and the aeration tank sus-
pended solids concentration was maintained at a comparatively constant
level (ranging between 2,000 and 2,300 mg/L), with no abnormal sludge
wasting activity.

A summary of the aeration tank profile at the termination of the  step
aeration studies is shown in Table 9.  The suspended solids values in
Table 9 show the effect of the mid-point addition of primary effluent
and also indicate a minimum of back mixing of the primary effluent
introduced at the aeration tank mid-point.  The ortho-phosphate results
indicate that a release observed on the mixing of primary effluent and
return sludge occurred only at the inlet end of the aeration tank and
not at the mid-point where the second addition of primary effluent took
place.  This aspect of step aeration operation is significantly dif-
ferent from that normally observed in profiles from plug flow, and that
the amount of phosphorus not removed by the step aeration configuration
is approximately equal to that quantity introduced at the mid-point  of
the aeration tank.

     Contact Stabilization

The final experiment in the mixing configuration series was a mixing
modification toward the contact stabilization mode of activated sludge
treatment.  This condition was achieved by introducing only return
sludge at the normal inlet of the test aeration tank (No. 2), making
the first half of the aeration tank a stabilization basin, and by in-
troducing 8 mgd of primary effluent at the mid-point, which made  the
final half of the aeration tank the contact portion of the system.   Dur-
ing this study the test aeration tank was operated with both clarifiers,
resulting in a slightly longer than normal detention time in the  clari-
fiers; however, previous low-flow tests indicated that this longer
secondary clarifier detention time did not impair phosphorus removal.

A plot of the monitoring results of this final study is  presented in
Figure 21.  Contact stabilization operation was started  early on  12/18
with a stabilization time of 9.2 hours and a contact time of 2.7  hours.
                                54

-------
                          15


                          10


                           5

                           0
                                                                                                      RETURN TO
                                                                                                      PLOG FLOW
Cn
Oi
                          10


                          5


                          0




                          20


                          10  —
                         7.0


                         6.0


                         5.0
                          TOTAL FLOW
r- '• ^^^^
_


FLOW ADDED AT MID-POINT








^ 1 	
1
mm —
                         400


                         200


                          0
          200


          100

           0
                                         — -•
                             12/12/69
                             12/13/69
                                                                12/14/69
                                                                      12/15/69
12/16/69
   I  F P  F N fl
                                                           TIME

PRIMARY EFFLUENT    FLOW  CONFIGURATION   TEST  NO.2 - STEP   AERATION

SECONDARY EFFLUENT NO.l - CONTROL                     FIGURE   20

SECONDARY EFFLUENT NO.2 - TEST

-------
                                              Table 9



                              Summary of Step Aeration  System Profile






                                                      Sample  Point
Parameter
DO, mg/L
pH
Sol. COD
Ortho PO
Tot. P,


, mg/L
4. mg/L
mg/L
NH3-N, mg/L
Sol. Tot
Tot. KN,
SS, mg/L
. KN, mg/L
mg/L

PE

6.3
180
9.8
10.6
23-9
26.0
28.0
112
VSS, mg/L
Sol. Mg,
Sol. Ca,
mg/L
mg/L
12. k
25.0
AT-1
0.2
6.5
75
30.7
192
23.8
—
22*4-
3,5^0
2,550
15.8
26.0
AT-2
0.2
6.5
65
21. ll-
190
22.3
22. k
227
3,535
2,575
13.7
25-5
AT-3
1.2
6.5
70
12.1
188
--
21.0
225
3,^50
2,500
10.il-
—
AT-^
0.3
6.7
60
11.5
130
20.9
21.0
208
2,285
1,640
10.2
25-3
AT-5
5.2
6.7
60
5-1
130
19.2
19. ^
198
2,2UO
1,650
8.7
2k. 2
AT-6
7.2
6.8
60
3.6
125
18.3
19.0
200
2,295
1.6UQ
Q.k
25.0
AT-7
7.8
6.8
60
--
128
17.5
18.2
196
2,325
1,685
8.1
2k. 2
RS

6.k
100
^1.5
510
23.0
23-5
600
9,730
7,085
16.6
31-5
SE
2.0
6.8
55
k.k
6.8
18.6
21.2
—
—
--
—
2k. 0
(Samples  collected on 12/16/69 10:00-12:00 a.m.)

-------
                            BEGIN CONTACT
                            STABILIZATION
Ot
                         16 f~
                         12 ~
                         10  r~
                                                                            CHANGED BACK TO
                                                                            PLUG FLOW
 10

  5

  0


8.0

7.0

6.0
_, 400
CS
200
" 0
l~~ y» — -J
~" ^s^' >*1— — **
~

L— s vJ
^^.—••^



"^~^>N /"~~'~^<



^
^^•^— ^^"~

—
—
X^^

    LEGEND
200
100
0
ENT
LOEN
- /^-
_ "' —

12/18/69
F NO. 1 - CONTROL

\*- 	

12/19/69

""^ 	 * 	 .

12/20/69


12/21/69
—
^ 	 ^-^

12/22/69
              PRIMARY EFFLUENT
              SECONDARY EFFLUE*
              SECONDARY EFFLUENT  NO.2 - TEST                           "i«t

                         FLOW  CONFIGURATION  TEST  NO.3 -  CONTACT  STABILIZATION

                                                           FIGURE  21

-------
At 8:00 a.m. on 12/19, the return sludge rate was  increased,  so  that  the
stabilization time was 6.6 hours and the contact time  2.5 hours.   As
indicated in Figure 21, a release of ortho-phosphate started  approxi-
mately eight hours after the beginning of this study and continued
throughout the duration of the study.  Abnormal excess  sludge wasting
took place on 12/17, and the aeration tank outlet  suspended solids were
reduced from 2,700 mg/L on 12/17 to 1,700 mg/L by  early 12/18.   The sus-
pended solids level in the remainder of the contact stabilization  study
ranged from 1,500 mg/L to 1,800 mg/L.  This abrupt change in  suspended
solids level at the start-up of this configuration study may  have  contri-
buted to the immediate phosphorus release.  However, as indicated  on
Figure 21, even after two days for stabilization of the operation  there
was no indication of a recovery of phosphorus removal.  During this study,
the dissolved oxygen concentration was well above  the  limiting ranges, and
the other parameters of pH and total carbon were normal.

At the end of the stabilization study, a terminal profile was taken across
the aeration tank, and is presented in Table 10.  These data  show  that the
first quarter of the aeration tank was equal to the return sludge  in  sus-
pended solids concentration and that the final half of  the aeration tank
had a fairly constant range of suspended solids concentration.   It is obvious
from the aeration tank soluble phosphorus results  that  the release and sub-
sequent uptake of phosphorus, which normally occur on  the mixing of the
primary effluent and return sludges, did not take place at the mid-point  of
the aeration tank.
As shown in Figure 21, when the contact stabilization mixing configuration
was changed back to the normal plug flow, recovery of phosphorus removal
was not immediate.  Early on December 23, Aeration Tank No. 1, which
contained considerable long-term aerated suspended solids during the period
of outage, was re-introduced into the activated sludge system and the parti-
tions between the test and control system were removed for restoration  of
normal operation.  Extremely heavy rains subsequently experienced on December
24 resulted in very low inlet primary effluent phosphate concentrations.
Therefore, as indicated by results of grab samples, it took until December
25 to achieve a 60 percent ortho-phosphate removal and until December 29 to
achieve complete recovery of phosphorus removal (85 to 95 percent) .

     Laboratory-Scale Mixing Configuration Tests

The interest in performing full-scale mixing configuration tests was
stimulated by results of earlier limited laboratory-scale tests which
were conducted in an effort to duplicate the full-scale phosphorus  removal
operation.  The limited laboratory-scale tests were performed chiefly
in September and October of 1969 and involved a 15-liter aeration tank
and a 4.5-liter clarifier.  The first experiment involved the pumping
of a continuous sample from the inlet end of the full-scale control
aeration tank to a laboratory-scale, completely-mixed aeration tank.
                                 58

-------
Ui
VO
                                                     Table 10


                                Summary of Contact Stabilization System Profile



                                                             Sample Point
Parameter

DO, mg/L
PH
Sol . Tot. P* mg/L
Tot. P, mg/L
Sol. Tot. KM, mg/L
Tot. KM, mg/L
SS, .mg/L
VSS, mg/L
Sol. Mg, mg/L
Sol . Ca, mg/L
PE

0.
6.
9.
11.
21+ .
25-


9-
22.


0
7
6
0
0
0
90
TO
4
0
AT-1
Stab
1.6
6.9
10.2
206
22.8
248
4,280
3,095
9.6
22.5
AT-2
il izat
2.5
6.8
9.6
194
23.0
230
^,050
2,925
10.4
22.5
AT-3
ion
3.0
6.9
9-2
160
22.6
202
3,290
2,460
9.2
22.5
AT-4
AT-5
AT-6
AT-7
RS
SE
Contact
0.7
6.9
9.8
86
21.8
118
1,700
1,335
10.4
21.5
5.0
6.9
9.0
91
21.2
125
1,780
1,^30
9.6
21.5
7.3
7.0
9.6
96
21.5
128
1,765
1,325
11.7
22.5
8.0
7.0
8.8
9^
20.8
127
1.770
1,330
9.6
22.5
0.0
6.8
24.0
208
22.4
256
4,180
3,270
12.2
25-5
4.0
7.1
8.8
—
21.2
—
—
--
8.3
22.0
       * During this profile study ortho-phosphate values  were  not measured  but  soluble  total  phosphorus
         was performed instead.
       (Samples collected on 12/22/69 10:00-12:00 a.m.)

-------
Over a one-week period of continuous operation, the laboratory-scale
aeration tank outlet soluble phosphate concentration showed  good  com-
parison to the full-scale system; phosphorus removal was  good, with
the soluble concentration in the effluent of less than 1.0 mg/L.

The next laboratory experiment was operation of this laboratory-scale,
completely-mixed activated sludge system with its own return sludge
(instead of using the full-scale return sludge as was done in the
previous test).  All laboratory-scale, completely-mixed activated sludge
systems with individual recirculation lost the high degree of phosphate
removal within 20 to 30 hours of start-up.  Operation for a  two-week
period did not show any indication of improvement of phosphorus removal
above 20 percent.  A graphical plot of phosphorus removal with time for
several typical laboratory-scale studies is presented in Figure 22.
Other mixing configurations are included in this test, in addition to
complete mixing were step aeration and contact stabilization;  a similar
loss in phosphorus removal was experienced.

The only laboratory-scale activated sludge studies that maintained
a high degree of phosphorus removal for a period up to 80 hours were
those performed in an ideal plug-flow system that consisted  of batch
aeration for 6 hours, settling for 2 hours, and drawing and  filling with
new primary effluent.  These results are shown in the upper  portion of
Figure 22.  In all the studies presented on Figure 22, fresh  primary
effluent was used as the feed material, and all systems were  started
up with full-scale return sludge; the initially indicated removal was
equivalent to that of the full-scale system at the time of startup.
The observations in Figure 22 were made prior to the initiation of
the full-scale mixing configuration experiment.  Complete data for
the studies depicted in Figure 22 are presented in Appendix A (Table A-12).

                         General Findings

Metal Results

Extensive metal analyses were performed during the phosphorus removal
project to aid in the assessment of the contribution of metal precip-
itation to the phosphorus removal phenomenon.  For the Baltimore  primary
and secondary effluents, average metal ion concentrations and an  approx-
imate cation-anion balance are presented in Table 11.  This  table also
gives a comparison between current metal averages and previous observa-
tions made by the FWQA that included more parameters than were considered
in this project.  Average results indicate reasonably typical domestic
wastewater characteristics, with fairly low calcium concentrations.  These
average values indicate greater removal (from primary effluent to secondary
effluent) of magnesium ion than of calcium ion.  The averages and the cation-
anion balances likewise indicate a fairly typical domestic wastewater.
                                60

-------
          00
      O_
       I
          40
          20 -
  DEAL PLUG FLOW ACTIVATED SLUDGE
(6 HR. AERATION, 2 HR. SETTL I NG , DRAW,
-----  PLUG FLOW - NO  WASTINfi
--  PLUG FLOW - WITH WASTING
        PLUG FLO'W - 5  HR. SETTLING
                                                     FILL)
         100
      C_D
      oe
      Li_>
   OTHER MIXING CONFIGURATIONS
   (CONTINUOUSLY FED WITH 6 HR.AERATION
   AND 2 HR,SETTLING)
        	  COMPLETE MIXING
                 STEP  AERATION
                 CONTACT STABILIZATION
                                    40
                        60
80
                        TIME  FROM START-UP - HOURS
  PHOSPHORUS  REMOVAL  IN  LABORATORY SYSTEMS
AFTER START  UP WITH  FULL-SCALE ACTIVATED SLUDGE
                            FIGURE   22
                                  —61 —

-------
                                           Table  11

                   Average Wastewater Metal Content and An ion-Cat Ion Balance
                                       Primary Effluent
Secondary Effluent

Metal

Na
Ca
Mg
Al
Fe
Cu
Zn


Cr
Mn
Ni
PK
r D
All Others - Less than
Chemical Results
Ortho Phosphate, mgP/L
Ammonia N, mg/L
Nitrate N, mg/L
Total Inorganic Carbon,
Chloride, mg/L
Approximate Balance for
Cat
Sod i urn
Calcium
Magnesium
Aluminum
Ferric
Ammon I urn
7/14-12/4/69
RFW
mg/L
70. 02
25-3
11.2
2.1
3.2
0.4
1.0


0.9
0.4
0.2


detectable 1 imit

9.2
23.8
0.1
mg/L 33
1202
Primary Effluent
ions, me/L
3.04
1.27
0.92
0.23
0.17
1.70
5/13-23/1968
FWQA
mg/L
____
27.0
9.6
6.5
4.0
0.5
0.5
Or
o
A i.
U . H
0.5
0.1
0.8
Or
. y


8.9
	
	
	
____

An ions,
Chlorides
Carbonate
Phosphate
Nitrate

Sulfate
7/14-12/4/69
RFWl
mg/L
68. 02
23.4
8.5
0.8
0.9
0.1
0.3


0.1
0.1
0.2




1.6
14.8
0.5
35,
120Z

me/L
3.38
2.75
0.59
0.01
6771
0.60
5/13-23/1969
FWQA
mg/L
_ _ __
26.0
7.6
3.0
0.7
0.4
0.5
Or
O
0/1
,*4
0.2
0.1
0.2
Oo
• Z


0.6
	
	
	









                                                   (by difference)
                                       7.33
1 System No. 2.
2B*»ed on Limited Number of Analyses.
 7.33

-------
To gain some insight on  the variation  of primary  effluent  metal  ion
concentration with time, a series of grab samples were  taken  during
two 3-day periods in February  1970 and analyzed for  specific  soluble
metal ion concentrations.  Chronological plots of these metal observa-
tions, along with profile metal observations across  the activated  sludge
systems are presented  for these two periods in Figures  23  and 24.   Pre-
vious metal observations on profile samples had been seriously questioned
due to the uncertainty of variations in inlet metal  ion concentration,
which could possibly be  responsible for any variations  observed  in the  pro-
file samples.

As shown in Figure 23, major phosphorus release occurred February  12,
1970 in the activated  sludge systems;  this apparently was  related  to
the previously-discussed bulking situation and abnormal excess sludge
wasting action.  The profile observations on Figure  23  indicate  that the
removal of calcium across the  system was minimal, but that a  significant
removal of magnesium occurred  at approximately the same time  as  ortho-
phosphate removal was  taking place.  Based on the average  primary  efflu-
ent metal ion concentration for the 6  hours prior to the profile sampl-
ing, the magnesium removal across the  activated sludge  system was  more
than 2 mg/L, while the calcium removal was less than 1 mg/L.

The second metal ion observation test  shown in Figure 24 was  performed
at a time when the normal high level of phosphorus removal was taking
place, and the graphical representation indicates significant removal
of magnesium but only  marginal removal of calcium.   The primary  effluent
total phosphorus concentration was abnormally high on February 28,  1970,
particularly when the  profile  series of samples were taken; the  ortho-
phosphate remained at  normal concentrations.  Since  the primary  efflu-
ent magnesium concentration had averaged around 10 mg/L for the  6  hours
prior to the profile study, the high levels of magnesium at the  head
end of the aeration tank indicate a magnesium release that corresponded
to the observed phosphorus release.  This magnesium  release at the  inlet
end of the aeration tank is similar to observations  made in other  pro-
file studies performed December 3 and  10, 1969 (Appendix A).   It is
also of interest to note in Figures 23 and 24 that soluble iron  removal
takes place near the inlet of  the aeration tank and  that the  system
maintains the low iron level thereafter.

A brief full-scale study was performed December 11,  1969 to determine
if a magnesium ion release can be observed when a low DO-ortho-phosphate
release is stimulated.  The limited observations  are presented in  Table 12.
The aeration tank outlet DO was lowered from 5.0  to  0.7 mg/L,  and  a
phosphorus release was stimulated, increasing the aeration tank  outlet
ortho-phosphate level  from 0.1 to 6.3  mg/L.  Simultaneously,  there  was
an indicated increase  in magnesium ion concentration of approximately
2 mg/L.  However, without knowledge of the primary effluent history
prior to this sampling period, the conclusiveness of these results  is
diminished.
                                 63

-------
          »'ARI AT ION OF METAL  IONS  WITH TIME
    -  15
        0
               rj    i
                                             N^CALCIUM
                                     .	_ MAGNESIUM
                                         ^^ ^       	
     ^^     IRON
i     i    T—T	1	r*
        2/12/70
       TIME
                                                                PROFILE TIME
I
'T	1
    2/13/70
              2/1 1/70
LEGEND
_____ PRIMARY EFFLUENT
_ SECONDARY  EFFLUENT  (SYSTEM N0.1)(NOT SHOWN  FOR IRON  AND CALCIUM)
          PROFILE ACROSS ACTIVATED SLUDGE  SYSTEM 1  AT 10:30 AM 2/13/70
1
„ t


4
e e
10
12
14
                  3        5        7        9        II       13       15
                  CORRESPONDING  SAMPLING  POINTS IN  ACTIVATED  SLUDGE SYSTEM
      SOLUBLE  METAL  ION OBSERVATION  TEST  NO.l
                               FIGURE   23
                                                                          30
                                                                          20
                                                                          10
                                                                            16
                                                                            -  10
                                   —64—

-------
           VARIATION OF METAL  IONS WITH TIME
                                                  PROFILE
                                                    TIME
        30
        20
        10
         0
                IRON
                                 .-•x^CALCIUM
                                          TOTAL
                                          PHOSPHORUS
                                            MAGNESIUM


TOTAL
PHOSPHORUS
                                                                   7
               2/27/70                2/Z8/70                  3/1/70
LEGEND                              TIME
   	 PRIMARY EFFLUENT
         SECONDARY EFFLUENT (SYSTEM  1)(NOT SHOWN FOR  IRON)

           PROFILE ACROSS  ACTIVATED SLUDGE SYSTEM  1 AT 10:30 PM 2/28/70
    i    20 T
                          34567

                          SAMPLING  POINT IN  ACTIVATED SLUDGE  SYSTEM
   SOLUBLE METAL  ION OBSERVATION TEST NO.2
                           FIGURE   24
                               —65 —

-------
                                 Table 12

             Full-Scale Observation of Changes in Magnesium
                      With Ortho Phosphate Release
         At End of Aeration Tank            Overflow of Final  Clarifier
12/11/69
Time
10:30 a.m.
11 :00 a.m.
12:00 a.m.
1:30 p.m.
2:30 p.m.
3:00 p.m.
3:30 p.m.
4:00 p.m.
4:30 p.m.
4:45 p.m.
5:00 p.m.
5:30 p.m.
12/12/70
9:00 a.m.
Ortho
mgP/L
Air
0.1
0.1
0.1
0.1
0.1
0.1
2.1
6.3
Air
2.0
0.1

0.3
P 0.0. Mg**
mg/L mg/L
Reduced From 20,000
5.0
4.2
3.8
3.0
1.2
0.9
0.8
0.7
I ncreased
4.8
6.5

7.0
9.6


9.8
10.6
11.6
12.8
Back To 6,
12.2
11.4

9.2
Ortho
mgP/L
to 6,500 SCFM
0.1
0.2
0.1
0.1
0.1
0.1
0.1
0.1
500 to 14,500
1.4
1.5

0.2
P D.O.
mg/L
8.5
7.6
7.2
6.5
6.0
3.8
2.5
1.5
SCFM
0.5
0.7

1.5
Mg++
mg/L
9.4


10.4
10.6
10.8
10.6

10.8
10.2


Note:   All  metal  ion  results  were  soluble  analyses.
                                     66

-------
As stated previously, weekly  samples  (involving  the  different  activated
sludge sampling points) were  composited and subjected  to metal analy-
ses, the complete results of  which are tabulated in  Appendix A (Table  A-3)
Table 13 is a summary of the  average  and  range of metal content of  the
activated sludge system composite samples.  In Table 14, the metal  con-
tent of aeration tank mixed liquor is expressed  in terms of weight  per-
cent of the suspended solids.  The overall averages  for both the control
and test systems are indicated along with selected weekly  composited
sample results to cover a range  of conditions.

The weekly composite metal analyses were  also used for a metal account-
ability study for phosphorus  removal  determination.  Although  this  is
circumstantial and  the most optimistic stoichiometric  combinations  were
used, these accountability results are of interest.  Detailed  results
are included in Appendix A (Table A-14),  and a summary is  presented in
Table 15.

In giving credit for biological  removal as accounting  for  one  part
of phosphorus for every 100 parts BODs, the metal ion  content  of the
waste excess return sludge can adequately account for  the  overall
phosphorus removal.

Miscellaneous Laboratory-Scale Tests

Additional limited  laboratory-scale tests were performed during the field
study to help define the effects of activated sludge on phosphorus  re-
moval and to include some of  the studies  listed  in the original contract
that could not be performed in the full-scale testing program.   A phos-
phorus removal comparison between full-scale performance and laboratory
batch-scale operation is presented in Figure 25.  All  tests were per-
formed simultaneously on March 1, 1970.   The full-scale values were taken
at appropriate times from sample points in activated sludge system
No. 1, in order to  follow the same segment of primary  effluent through
the system.  Although the overall removals were  quite  comparable for
the full-scale and  batch observations, the phosphate removal was more
rapid in the small, highly aerated laboratory system than  in the full-
scale system.  An additional  simultaneous test,  shown  on Figure 25, was
conducted with the  primary effluent plus  an additional 15  mg P/L of
ortho-phosphate.  In the 3-hour observation period of  this batch test
(No. 2), the percentage removal was lower, but a significantly larger
absolute quantity of phosphorus was removed.

A brief laboratory  test of phosphorus release during long-term aeration
was performed, and  the results are presented in  Figure 26. A continuous-
recording pH meter was used for this  experiment,  and intermittent grab
samples were taken.  The test was initiated with activated sludge mixed
liquor from the control system aeration tank outlet.  At the beginning
of the test the pH was 7.2, and the soluble total phosphate was 0.2 mg/L.
The high level of aeration in the laboratory-scale system  resulted  in  an
                                 67

-------
                                                        Table 13
                                        Summary Of Weekly  Composite Metal  Analyses
                                                    7/14/69 - 12/23/69
00
Source

Primary Effluent

Secondary Effluent
(Control No.1)

Secondary Effluent
(Test No.2)

Aeration Tank Outlet
(Control No.1)

Aeration Tank Outlet
(Test No.2)

Return Sludge
(Control No.1)

Return Sludge
(Test No.2)

Avg
Range
Avg
Range
Avg
Range
Avg
Range
Avg
Range
Avg
Range
Avg
Range
Calc i urn
mg/L
25.3
21.8-30.0
23.6
18.6-28.0
23.2
19.0-25.5
53.3
31.0-90.0
44.0
27.5-74.0
118
73-168
113
59-198
Maqnes i urn
mg/L
11.2
8.8-14.2
8.1
6.1-10.7
8.9
6.5-12.4
30.2
23.7-40.0
28.2
18.0-48.0
105
42-192
90
37-147
I ron
mg/L
3.2
1.3-6.0
0.9
0.1-2.4
0.7
0.1-2.1
24.6
10.3-36.0
25.3
8.8-56.0
110
43-218
99
53-190
Al umi num
mg/L
2.1
0.8-3.8
0.7
0.5-1.5
0.8
0.5-3.5
15.4
5.5-33.0
15.7
4.5-44.0
78
32-133
59
20-110
Copper
mg/L
0.4
0.2-0.9
0.1
<0.1-0.2
0.1

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                                                          Table 14

                                     Observations on Metal Content of Activated Sludge
                                                  at End of Aeration Tank
Date

7/14-12/4
7/14-12/23
8/4-8/69
8/4-8/69
9/2-5/69
9/2-5/69
10/7-10/69
10/7-10/69
10/28-31/69
10/18-31/69
12/18-23/69
2/28/70
System
Avg.
Avg.
Avg.
Avg.
Avg.
Avg.
Avg.
Avg.
Avg.
Avg.
Avg.
Grab
No.
No.
No.
No.
No.
No.
No.
No.
No.
No.
No.
No.
1
2
1
2
1
2
1
2
1
2
2
1
Total P
Removal
Percent
75
66
69
67
82
85
72
87
92
39
32
95
Sol ids
Aeration Tank
SS - mg/L
2,070
1,980
2,150
1,450
2,270
3,040
1,870
1,810
1,970
1,920
1,620
1,860
Phosphorus
P/SS
%
4.5
4.2
3.7
3.7
5.0
4.5
4.1
5.1
4.9
2.6
4.3
4.5
Calci urn
Ca/SS
°/0
1.5
1.1
2.7
2.7
-
0.67
0.40
1.8
1.3
1.9
2.1
Magnesium
Mg/SS
%
1.1
1.0
1.0
1.3
1.4
1.3
0.93
1.10
1.4
1.0
0.9
I ron
Fe/SS
1.1
1.2
1.1
1.3
1.7
1.2
1.1
1.2
1.2
1.1
1.7
1.5
Al uminum
Al/SS
%
0.71
0.75
0.64
0.65
1.4
1.4
1.0
2.0
0.79
0.46
0.77
_
Zinc
Zn/SS
%
0.36
0.39
0.34
0.53
0.39
0.37
0.38
0.41
0.26
0.27
-
_
Copper
Cu/SS
%
0.17
0.19
0.18
0.15
0.22
0.23
0.29
0.28
0.06
0.09
-
_
Note:  Metal results are total content analyses.

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                                            Table 15

                  Average of Computations on Theoretical Accountability for
                                 Observed Phosphorus Removal
                                                     Control System              Test System
                                                    (7/14 - 12/6/60)          (7/1*1 - 12/22/69)
Average System Performance
  Phorphorus Removal,  Percent                              79                        66
  Phorphorus Removal,  mg P/L                              8.8                       7.3

Accountability Efforts:

  Minimum Biological Requirements, mg P/L                 1.5                       1.5
    (Based on P/BOD  Removed = 0.01)

  Possible Metal  Removal (Average Value)
    Calcium    (Assume P/Ca = 0.52), mg P/L               1.4                       1.4
    Magnesium  (Assume P/Mg = 0.86), mg P/L               2.7                       2.4
    Iron       (Assume P/Fc = 0.55), mg P/L               1.3                       1.5
    Aluminum   (Assume P/AI = 1.14), mg P/L               1.7                       1.5
    Copper     (Assume P/Ca = 0.48), mg P/L               0.1                       0.1
    Zinc       (Assume P/Zn = 0.47), mg P/L               0.3                       0.4

Total  (Average From Appendix Table A-14)                  9.0                       8.8

Difference                                               +0.2                      +1.5

-------
       ALL TESTS  PERFORMED AT  SAME TIME ON  3/1/70
            1/12         2/12                 5/12
               POINT ALONG FULL SCALE AERATION TANK
  10
Q_
CD
                            TIME  - HR
  20
LABORATORY BATCH TEST  NO.2
4L  P.E.  PLUS 1L R.S.  PLUS 15 MGP/L
(REMOVAL =11.6 MGP/L  OR 555)
  10  —
                                                                 _ 300
  FULL SCALE PLANT
  20% RECIRCULATION
  (REMOVAL = 6.6 MGP/L OR 88%)
                                         8/12
  LABORATORY BATCH TEST NO 1
  4L P.E. PLUS  U R.S.
  (REMOVAL =7.0 MGP/L OR 93i)
                                                                   300
                                                                  200
                                                                   100
                             TIME - HR
            PHOSPHORUS  REMOVAL COMPARISON
     BETWEEN  FULL-SCALE AND  LABORATORY  TESTS

                              FIGURE 25
                              —71 —

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increase in pH to 7.8 within the first 2 hours of aeration.  In Figure
26, it is interesting to observe that over 30 mg P/L of soluble total
phosphorus was released before the pH went below the initial value  of
7.2.  Although this brief study is not conclusive, it indicates that
a significant portion of the phosphorus is subject to a biological
release.

Comparison Between Activated Sludge and Trickling Filter

During the formal field study, the daily composite samples of regular
plant operation were analyzed for various chemical parameters.  A sum-
mary of the results is presented in Table 16, and complete analytical
results for all daily composite plant samples are included in Appendix
A (Table A-A) .

As indicated in Table 16, the plant samples include 24-hour composites
across the entire Back River Wastewater Treatment Plant, including
intermediate points between the raw inlet flow and the two final secondary
effluents.  The activated sludge secondary effluent was a composite
sample from both the test and control activated sludge systems, and
therefore, included the frequently-impaired test system effluent result-
ing from various operational variations.  The secondary trickling filter
effluent sample was taken at the point of humus tank overflow to the
receiving waters.  To be certain that the samples collected by plant
operating personnel were representative, the project staff, on October
31, 1969, collected a trickling filter effluent composite sample, making
a special effort to assure it was truly representative of the total
trickling filter effluent.  The results of analysis of this sample were
within 5 percent of those performed on the regular plant sample for that
date, indicating satisfactory collection of the plant samples.

The removal values presented were computed directly from values of  the
primary effluent and secondary effluent concentrations, based on plant
samples collected between July 31 and December 12, 1969.  The averages
indicated in Table 16 show a significant difference in both total phos-
phorus and ortho-phosphate removal across the activated sludge system
as compared to the trickling filter.  In fact,  since the overall second-
ary effluents had a higher proportion of phosphorus in the ortho-phosphate
form than did the primary effluents, very frequently the trickling  filter
showed no net removal of ortho-phosphate.  The total carbon and COD re-
movals also showed the expected higher performance of the activated sludge
system.  The nitrogen removals across the two systems showed closer compari-
son to the total carbon removals than to the phosphorus removals.   In both
systems, a significant amount of nitrogen was discharged in the effluent,
as ammonia nitrogen.  Although the highest single sample values of  combined
nitrate-nitrite nitrogen were observed in the effluent of the activated
sludge system, the average value in the trickling filter effluent was high-
er.  This was attributed to the operational changes imposed on the  activated
sludge system, especially oxygen limitations which inhibited the growth and
accumulation of significant numbers of nitrifying organisms.
                                72

-------
NJ
CO
                       INITIAL SAMPLE TAKEN FROM END OF
                       AERATION TANK NO.1 ON 10/17/69
TOTAL SUSPENDED SOLIDS   - 2160 MG/L
VOLATILE  SUSPENDED SOLIDS - 1530 MG/L
TOTAL PHOSPHATE
SOLUBLE  TOTAL PHOSPHATE
pH         -
                                               130 MGP/L
                                                0.2 MGP/L
                                                7.2
                                              30         40
                                            AERATION  TIME - HOURS
                                                     60
70
        LABORATORY  TEST OF PHOSPHATE  RELEASE ON LONG  TERM AERATION
                                               FIGURE 26

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                                                        Table 16

                                             Summary Of Comparison Between
                                   Activated Sludge And Trickling Filter Performance


                                                                                       Trickling Filter(TF)
                              Raw         Degritted   Primary    Activated Sludge(AS)  Filter   Secondary    TF        AS
An a 1y s i s                      Wastewater  Wastewater  Eff1uent   Secondary Effluent    Outlet   Eff1uent     Removal   Removal


Ortho Phosphate (P)

Total Phosphorus (P)

Ammonia Nitrogen (N)

Total Kjeldahl  Nitrogen (N)

Total Carbon (C)

COD

Combined Nitrite-Nitrate (N)  0.11

     Note:   All  results are averages from AppendTx Table A-4 and are for daily
            composite samples collected by plant operating staff during the period
            8/1/69 and 12/19/69.  The secondary activated sludge results are for an
            equal  volume composite of both test and control activated sludge systems.
            Percent removals can not be calculated from this table.
mg/L
8.0
10.6
18.7
26.0
139
211
0.11
mg/L
8.4
11.3
20.4
28.4
143
219
0.11
mg/L
10.2
12.2
22.6
26.6
143
219
0.23
mg/L
2.3
3.2
12.9
14.7
70
64
1,45
mg/L
10.1
11.7
20.3
22.9
92
117
1.06
mg/L
10.0
11.5
18.6
21.4
90
112
1.71
°/0
8
9
14
22
37
46
__
%
81
74
42
47
50
69
__

-------
Correlations of Wastewater Characteristics

To evaluate wastewater characteristics such as unique wastewater  component
relationships at Baltimore, the existence of correlations between dif-
ferent parameters measured in the primary and secondary effluents was
explored.  The parameters considered in the correlations were:  total
phosphorus, ortho-phosphate, total Kjeldahl nitrogen, ammonia nitrogen,
total carbon, COD, and BOD.

The correlation between ortho-phosphate and total phosphorus for both
the primary and secondary effluents is shown in Figure 27.  The data
points on Figure 27 were those taken from the profile observations or
from daily composite analyses when both total phosphorus and ortho-phosphate
analyses were run on the same samples.  The primary effluent showed wide
scatter between total phosphorus and ortho-phosphate; however, an approxi-
mate correlation line is indicated, which shows an average relationship
of 0.75/1 ortho-phosphate to total phosphorus over a limited range.  Fig-
ure 23, presented previously, showed that on February 28, 1970, the pri-
mary effluent had ortho-phosphate and total phosphate concentrations of
8.5 and 20.5 mg/L, respectively, and that twelve hours later the ortho-
phosphate and total phosphorus concentrations were 8.4 and 9.5 mg P/L,
respectively.  In that time, there had been no significant change in the
primary effluent suspended solids.

The secondary effluent ortho-phosphate to total phosphorus comparison
shows a higher ratio, because most observations indicated that most of
the phosphorus concentrations in the final effluent were in the ortho-
phosphate form.  The change of soluble total phosphorus to the ortho-
phosphate form across the activated sludge system is clearly demonstrated
in the 2/28/70 profile shown in Appendix A (Table A-6).  At extremely
low secondary effluent phosphorus concentration measurements, the lower
plot in Figure 27 shows the effect of the phosphorus contained in the
suspended solids.

The possibility of a correlation between the phosphorus and nitrogen
content in the Baltimore wastewaters was explored, and the results are
presented on Figure 28.  The extreme scatter of the points indicates
the independence of both total phosphorus from total Kjeldahl nitrogen
and of ortho-phosphate from ammonia nitrogen; this is true for both
primary effluent and secondary effluent wastewater analyses.  Although
not all of the individual monitoring analyses are plotted, sufficient
points are included to demonstrate the range observed.  Industrial dis-
charges into the Baltimore municipal wastewater system may have accounted
for the severe changes in nitrogen without comparable changes in phos-
phorus .

Interest in the relationship between total phosphorus and total organic
carbon was indicated early in the study, and the apparent lack of correla-
tion of these parameters can be seen in Figure 29.  The possible correla-
tion between total phosphorus and suspended solids for both primary

                                75

-------
  15
  10
                              10            15
                       TOTAL PHOSPHORUS  - MGP/L
               I     I     I
           SECONDARY EFFLUENT
                   34567
                      TOTAL PHOSPHORUS  - MGP/L
CORRELATION  BETWEEN   ORTHO  AND  TOTAL  PHOSPHATE
                       FIGURE  11
                         —76—

-------
     20
 i
 CSi
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                                                                  40
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10
20
                                                    30
                                                            40
                        SOLUBLE AMMONIA NITROGEN - MGN/L
INDEPENDENCE  OF  PHOSPHORUS  AND  NITROGEN
            IN  BALTIMORE   WASTEWATER
                    FIGURE 28
                        —77—

-------
 i

co

oc.
C3

Q_
CO
 I

CO
Q_
CO
     20
     15
           10
     15
           10
         •#.

        0
                  100
                                  200         300

                                       TOC - MG/L
400
500
                                                       200
                              SUSPENDED SOLIDS  riG L
NOTE:
 •  PRIMARY EFFLUENT
 .- SECONDARY EFFLUENT
          LACK  OF  CORRELATION  OF  TOTAL   PHOSPHORUS
               WITH  TOC  AND   SUSPENDED   SOLIDS
                            FIGURE  29
                         —78—

-------
effluent and secondary effluent  is also  shown  in  Figure  29.   The  releases
of phosphates that occurred in the secondary effluent  apparently  were not
associated with either the total organic carbon or suspended  solids  con-
centrations .

Of all the parameters evaluated, probably the  total  organic carbon (TOC)
and the chemical oxygen demand (COD) showed the best correlation,  as  in-
dicated in Figure 30.  Most of the COD analyses run  during this study
were made with the Technicon Auto-analyzer system, and the upper  plot
in Figure 30 is a correlation between TOC and  Auto-analyzer COD.   These
observations include both primary effluent and secondary effluent values
and all points plotted were derived  from the automatic instrumentation
system that mechanically split the sample streams so that both automatic
determinations (TOC and COD) were made simultaneously.   There still  is
some scatter in the data, although a line of best fit  indicates an ap-
proximate 0.45 to 1 relationship of  TOC  to COD.

At the bottom of Figure 30, limited  observations  on  the  relationship
between TOC and manual COD determinations are  presented.  These points
show considerably more scatter,  and  an approximate line  of best fit
indicates a slightly lower TOC to COD ratio (0.30).  Although this
lower value is closer to the anticipated theoretical value, the manual
COD analysis on both the primary effluent and  secondary  effluents  in-
cluded all suspended solids; whereas, the automatic  instrument system in-
corporated limited solids screening  in the sampling, due to the small-
diameter transmission lines.

Figure 31 presents an evaluation of  the  correlation  between TOC and BOD
(both 5-day and 20-day).  The BODs values were taken from the results
of the daily composites samples, and the TOC values  were the  average  moni-
toring results for the respective days.   There is considerable scatter in
the results, and the fact that they  were not performed on precisely the
same sample probably contributed to  this variability.  Points for  both
the primary effluent and secondary effluent analyses are presented and
a general trend line is indicated.

Limited long-term (20-day) BOD analyses  were performed on certain daily
composites samples.  The results of  a TOC/BOD2Q correlation evaluation
are shown on the bottom of Figure 31.  Both normal BOD and nitrification-
inhibited BOD results are indicated, and approximate trend lines  are
shown.  Again, there was considerable scatter  in  the data, when the BOD
composite values were compared with  average monitoring TOC results.

Analysis of the BOD bottles at the end of long-term  BOD  determinations
indicated considerable nitrate formation.  To  inhibit  this nitrification,
5 mg/L of thiourea were added to the dilution  water.   The presence of
thiourea did not reduce the BOD^ values, but showed  a  dramatic reduction
of terminal nitrate concentration of BOD20 values.   A  limited compari-
son between BOD5 values and BOD2o values is shown on Figure 32.   For  all


                                 79

-------
   300
   200
   100
                  100
           200
300
400
500
               AUTOANALYZER  CHEMICAL OXYGEN DEMAND  (COD) - MG. L
                   (LIMITED  SOLIDS  SCREENING IN SAMPLING)
   200
NOTE:
 •  PRIMARY EFFLUENT
 •  SECONDARY EFFLUENT
MANUAL  CHEMICAL OXYGEN DEMAND  (CODH) - MG/L

    (TOTAL  SAMPLE INCLUDING ALL  SOLIDS)
                                                               500
    CORRELATION   BETWEEN  TOC   AND  COD
   FOR  PRIMARY   AND   SECONDARY   EFFLUENT
                    FIGURE  30
                         —80—

-------
           CJ


           CJ
               200
           CJ


           CJ
               100
                                        FIVE DAY BOD - MG/L


                       NOTE:
                        • NORMAL BOD PRIMARY EFFLUENT
                        • NORMAL BOD SECONDARY EFFLUENT
                        O NITRIFICATION  INHIBITED BOD PRIMARY EFFLUENT
                        A NITRIFICATION  INHIBITED BOD SECONDARY EFFLUENT
                                T
                                100             200            300

                                   LONG TERM BOD  (20  DAY)  -  MG/L
400
                CORRELATION   BETWEEN   TOC  AND  BOD
FOR  DAILY   COMPOSITES  OF  PRIMARY  AND  SECONDARY  EFFLUENT
                               FIGURE  31
                                      —81 —

-------
the samples shown in Figure 32, both uninhibited and inhibited  BOD5  values
were the same and only the long-term values showed  a difference.   The  actual
observations and terminal nitrate concentrations are shown  in Appendix A
(Table A-15).  The purpose of this brief nitrification  study was  to  attempt
to derive a value for carbonaceous BOD that would be more comparable to total
organic carbon observations.  The results  (Figure 30 and 31) showed  that by
eliminating the nitrogenous oxygen demand with thiourea for this  wastewater,
the long-term BOD was in a more reasonable range (less  than the COD  value
for a sample of a given level of TOG).  Also, the inhibited BOD2Q value in
Figure 32 were more proportional to the BODc values, where  little or no nit-
rification took place.

The final parameter correlations that were evaluated and presented on
Figure 33 include the relation between Auto-analyzer COD and BOD,- and  a
comparison between auto-analyzer COD and manual COD.  The auto-analyzer
COD to BOD5 comparison shows considerable scatter,  and  again, as  in
Figure 31, the daily composited BOD^ values were compared to the  average
COD of automatic monitoring results.

The limited auto-analyzer COD to manual COD comparison  in Figure  31
showed a rough correlation ratio of about 0.70 to 1.  Contributing to  this
low ratio were such factors as screening of suspended solids, analytical
method differences in digestion conditions, and inability to compare
results on identical samples.  Also, of all the automated analytical
systems used for this study, most difficulty was encountered with the
COD auto-analyzer in achieving consistent and reliable  analytical per-
formance .
                                82

-------
    600
c=>
CO
     200
          NOTE:

          •  NORMAL BOD PRIMARY  EFFLUENT
          •  NORMAL BOD SECONDARY EFFLUENT
          O  NITRIFICATION INHIBITED WITH  THIOUREA PRIMARY EFFLUENT
          A  NITRIFICATION INHIBITED WITH  THIOUREA SECONDARY EFFLUENT
                                    BOD5  - MG/L
      COMPARISON  BETWEEN  BOD5   AND  BOD2Q   VALUES
                           FIGURE 32
                                —83—

-------
 400
 300
 200
 100
                                BOD5 - HG/L
      NOTE:
        •  PRIMARY EFFLUENT
        •  SECONDARY EFFLUENT
  100
                             COD (MANUAL) - MG/L
                    (TOTAL SAMPLE INCLUDING ALL SOLIDS)

CORRELATION   BETWEEN   AUTOANALYZER   COD
       AND  MANUAL  COD   AND   BOD5
                   FIGURE  33
                        — 84 —

-------
                            SECTION IV

                DISCUSSION OF EXPERIMENTAL RESULTS

  Demonstration of Full-Scale Activated Sludge Phosphate Removal

Analytical results of process performance have demonstrated on a long-
term basis that the activated sludge portion of the Back River Wastewater
Treatment Plant is capable of providing a consistently high degree of
phosphorus removal.  Observations have shown that this removal is not
dependent upon the seasons and occurs consistently throughout the year.
One important aspect of activated sludge phosphorus removal is disposal
of the phosphorus contained in the waste activated sludge, which comprises
the net removal of the system.  At Baltimore, this is accomplished by
pumping the waste activated sludge back to the primary clarifiers, from
which it was distributed throughout the total plant flow.  Approximately
12 percent of any subsequently-released phosphorus returned to the
activated sludge system, the remainder going to the trickling filter
system.  Therefore, the overall net phosphorus removal of the combined
activated sludge and trickling filter at the Baltimore Back River Waste-
water Treatment Plant was not significantly higher than that observed at
other municipal wastewater treatment plants, because there was no terminal
disposal for phosphorus.  The phosphorus from the abnormally high removal
in the activated sludge system was subsequently discharged through the
trickling filter system.

Continuous monitoring data collected during the four-month period from
August to December 1969 on the control portion of the activated sludge
system indicated that total phosphorus removals were 73 percent or greater
90 percent of the time.  It should be pointed out that the control acti-
vated sludge system was operated at previously-evolved normal plant condi-
tions and not necessarily at conditions selected as optimum for phosphorus
removal.  During this period, the secondary effluent from the control sys-
tem had a total phosphorus content of below 2.7 mg P/L 90 percent of the
time.  The total phosphorus content of the activated sludge generally was
between 2 and 5 percent, and since the suspended solids concentration of
the secondary effluent normally was between 10 and 30 mg/L, it appears that
a major portion of the phosphorus in the final effluent can be attributed
to that contained in the suspended solids.

Part of this full-scale demonstration was the development and use of an
automatic sampling and analytical system to provide continuous monitor-
ing data and immediate knowledge of plant performance.  Such a system
was developed, and  the  overall effectiveness for the survey period re-
sulted in valid instrumental data monitoring 87 percent of the time.
Standards were automatically introduced to the monitoring system on a
definite schedule  to assure validity of the analytical measurements.
                                85

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         Definition of Activated Sludge Phosphorus Removal

Dissolved Oxygen

Oxygen limiting conditions in the aeration tank were found to be a critical
parameter in maintaining the phosphorus removal at Baltimore.  Although  a
critical concentration of dissolved oxygen was not defined, observations
indicated that when the dissolved oxygen level at the end of the aeration
tank dropped below 2.0 to 3.0 mg/L, conditions in the system became such
that a rapid release of ortho-phosphate took place in the secondary effluent.
When adequate aeration was resupplied to the system, a rapid recovery of phos-
phorus removal was achieved.  In the conventional plug-flow activated sludge
system at Baltimore, a D.O. level of 2.0 to 3.0 mg/L at the end of the aera-
tion tank occurs with significantly lower D.O. levels at other points in the
aeration tank.  Therefore, the Baltimore system normally operated with 0.5
mg/L D.O. in the entire first half of the aeration tank, which increased
oxygen transfer efficiency.  During most of the year, a moderate aeration
level of 1.2 scfm of air per gallon of wastewater was adequate for phos-
phorus removal.

In every case where a phosphorus release was caused by a low D.O.
condition at the end of the aeration tank, the removal of total organic
carbon across the system was impaired.  Effective phosphorus removal
only occurred when oxygen was not limiting and efficient carbon removal
was occurring.  Oxidation reduction potential (ORP) data showed distinct
variations when phosphorus releases were stimulated by low D.O. conditions
in the aeration tank.   However, in comparisons of observed responsiveness,
D.O. measurement at the end of aeration tank was more sensitive than ORP
to any changes in aeration that stimulated a phosphorus release.

Suspended Solids

Aeration tank suspended solids concentration (and variations thereof)
is another parameter important in the definition of activated sludge
phosphorus removal.  The full-scale data collected during this project
do not rigorously define the critical minimum suspended solids concentra-
tion necessary for high phosphorus removal.  Aeration tank suspended
solids level in the 1,200-3,700 mg/L range did not affect phosphorus
removal; however, very limited data indicated that suspended solids in
the 600-900 mg/L range may have impaired the phosphorus removal.

The rate of wasting of excess activated sludge appeared to be a very
important factor.  Rapid wasting of activated sludge creating a sig-
nificant change in the suspended solids inventory over a short period
of time appeared to upset the process, and temporarily impaired the
degree of phosphorus removal.  This occurrence was observed on at
least four occasions during the field study.  The quantity of suspended
solids in the secondary clarifier, reflected by the depth of sludge
                                86

-------
blanket, ranging  from 1  to 11  feet deep,  did not  appear  to have  any  nega-
tive effect on  the phosphorus  removal.  However,  the  Baltimore activated
sludge system secondary  clarifiers have comparatively efficient  sludge-
removal mechanisms, and  most of the  time  there was very  little sludge  in
the clarifier due to 25  percent recycle,  so that  little  long-term data
were collected  on blanket fluctuations.

Mixing Configuration

Mixing configuration evaluation was  a very important  part of  the definition
studies.  The conventional activated sludge aeration  tanks at Baltimore
have many design  features that maximize the occurrence of plug flow,
and tracer-study  responses clearly demonstrate the existence  of  this
flow condition.   Samples taken across the length  of the  activated sludge
system during normal operation showed a phosphorus profile of a  distinct
release in the  first part of the aeration tank followed  by an uptake
region downstream in the system.  Limited modifications  of the full-scale
system toward complete mixing  were inconclusive because  no significant
departure from  plug flow was achieved.  Full-scale studies with  the acti-
vated sludge system modified toward  step  aeration showed reduced phos-
phorus removal  after the aeration tank mid-point, where  the second addi-
tion of primary effluent took  place.  However, recovery  to a  high level
of phosphorus removal was rapid when the  systems  were restored to plug
flow.  Modification of the same system to contact stabilization  for a
brief study period resulted in an even greater impairment in  phosphorus
removal.

Reported laboratory-scale continuous activated sludge tests using the
mixing configurations of complete mixing, step aeration, and  contact
stabilization were unsuccessful in maintaining the high  degree of phos-
phorus removal.   Phosphorus removal  was maintained for a 3-day period
with a crude draw and fill laboratory system.  However,  there is  a need
for developing  a  satisfactory  continuous  laboratory system that  has the
necessary plug  flow configuration and has operating characteristics that
duplicate the consistent full-scale  phosphorus removal observed  at
Baltimore.

Flow

Definition studies of flow and observations on organic loading indicated
no adverse effects on phosphorus removal  within the scope of  conditions
included in the study.   Constant operation, which included aeration tank
detention times,  ranging from  2.5 to 12.0 hours,  and  diurnal  flow
variations were the range of flow conditions included in these evaluation
studies.  During  the study period, composite primary  effluent BOD5
concentrations  ranging from below 100 mg/L up to  380  mg/L showed no ad-
verse effects on  activated sludge phosphorus removal!
                                 87

-------
Other Factors

The trickling filter performance observed at the Back River Wastewater
Treatment Plant consistently showed significantly lower levels of
phosphorus removal than the activated sludge system.  The recycle of all
sludge handling liquors in the Baltimore system contributed to the high
phosphorus load on secondary treatment and may have influenced this low
trickling filter phosphorus removal.  However, it is difficult to envi-
sion that the trickling filter could remove amounts of phosphorus in a
manner comparable to the activated sludge system.

The precise mechanism whereby phosphorus removal takes place at Baltimore
has not been defined, and the full-scale data observed in this study
were not adequate for solution of this question.  The observed release
of phosphorus over that of the incoming primary effluent and return
sludge (at the inlet end of the aeration tank) and the maximum pH
value as low as 6.7 do not appear to be compatible with the calcium
precipitation explanation of phosphorus removal.  Also, release and up-
take of magnesium ion, which appears to parallel that of phosphate
across the activated sludge system, is not explained by current pre-
cipitation explanations.  It should be noted that Baltimore's domestic
wastewater cannot be considered as a hard wastewater, and the metal ion
concentrations do not appear to be abnormally high.

Some additional observations appear to suggest biological sludge as
the mechanism of phosphorus removal at Baltimore.  One explanation is
the apparent sensitivity of phosphorus removal to upset by abrupt solids
wasting and mixing configuration; since it required as much as 3 to 4
days to recover once the removal ability was seriously impaired.  Another
is the rapid release of phosphorus when oxygen-limiting conditions occur
in the aeration tank and recovery upon adequate aeration, without sig-
nificant changes in pH taking place.

A further indication of solids dependency is the movement of the point
in the system of most rapid reduction in phosphorus concentration.  This
reduction was observed to vary anywhere from the one-quarter point to
the end of the aeration tank, and did not necessarily correspond to a
sharp change in D.O. or pH.  Biological solids involvement was also indi-
cated by laboratory studies, which showed a significant release of phos-
phorus on long-term aeration at high levels of pH.

                           Optimization

The following general observations indicate that normal operating condi-
tions at the activated sludge system of the Back River Wastewater Treat-
ment Plant were close to the optimum for phosphorus removal for this
particular plant:
                                88

-------
     1.  Changes from plug flow  (in the form of other mix-
         ing configurations) impaired the phosphorus removal.

     2.  A higher degree of aeration, beyond the 3-5 mg/L
         D.O. at the end of the  aeration tank, at Baltimore
         (necessary for keeping  oxygen from being limiting
         parameter), appeared to offer no improvement in
         phosphorus removal.

     3.  Suspended solids levels above 2,000 mg/L did not
         provide any improvement in phosphorus removal.

     4.  Continuous sludge wasting, with the maximum rate
         of wasting rarely exceeding 3 times the overall
         average rate for any extended period of time, ap-
         peared necessary to eliminate any phosphorus re-
         moval impairment stimulated by abrupt wasting of
         suspended solids.

     5.  A wide range of hydraulic loadings showed no nega-
         tive effect on phosphorus removal; thus, hydraulic
         loading, within the range encountered in this study,
         (aeration detention times of 2.5 to 12 hours) is not
         a significant factor in optimization of activated
         sludge phosphorus removal at Baltimore.

One very necessary factor to the optimization of activated sludge phos-
phorus removal is the provision  somewhere in the treatment system of a
positive phosphorus removal and  disposal stage for the sludge-handling
supernatant wastewaters.  The most economical alternative for terminal
phosphorus removal will very likely be different for each treatment
plant.

An assessment of the application of the type of activated sludge phos-
phorus removal observed at Baltimore to other municipal wastewaters is
beyond the scope of this research study.  However, no obvious unique
wastewater characteristics or abnormal metal ion concentrations that
may limit the application of this process were observed at Baltimore
during the field study portion of this project.  At the present level
of understanding of the phenomenon, only actual experimentation at a
particular location could truly  confirm the applicability of this form
of activated sludge phosphorus removal.  Observations at other activated
sludge plants across the United  States further encourage the possibility
of wide application.
                                89

-------
                             SECTION V

                          ACKNOWLEDGEMENTS

The support of the City of Baltimore, and particularly the Bureau of
Engineering of the Department of Public Works,  is acknowledged with
sincere thanks.  Mr. William A. Hasfurther, Chief, Division of Waste-
water, provided valuable assistance.

The plant modification, laboratory and analytical installation and
project maintenance support were provided by the supervisory and main-
tenance staff of the Back River Wastewater Treatment Plant operating
staff, and particular  recognition is given to Mr. C. H. Hawthrone,
Superintendent, and Mr. R. Harmon, Mr. K. Hartman, Mr. C. Achatz, and
Mr. H. Urtes.

Activated sludge treatment plant operating staff made a significant
contribution to the completion of the field portion of this project
and particular acknowledgement is made of the efforts of D. McCauley,
S. Nierwienski, L. Caldarone, R. Gernhart, W. Byard, and J. Bradshaw.

The field studies, analytical work, data analysis and interpretation
and report preparation were performed by ROY F. WESTON, West Chester,
Pennsylvania.  The field team consisted of Dr. W. F. Milbury, Project
Scientist/Engineer, F. L. Doll, Project Chemist, P. J. Norenbrock,
Laboratory Technician, and R. L. Wooten, Laboratory Technician.  Mr.
V. T. Stack, and Dr. M. N. Bhatla, contributed valuable guidance to
this project.

The support of the project by Federal Water Qiiality Administration
and the help provided  by E. F. Barth, Project Officer, is gratefully
acknowledged.
                                91

-------
                              SECTION  VI

                              REFERENCES

 1.   Levin, G. V., and  Shapiro,  J.,  "Metabolic  Uptake  of Phosphorus by
      Wastewater Organisms,"  Journal  of  the Water  Pollution  Control  Fed
      eration, WPCF,  Vol . 37,  No. 6,  p.  800  (June  1965).

 2.   Smith, I. W. , et al . , "Volutin  Production  in Aerobacter Aerogenes
      Due to Nutrient  Imbalance."   Journal of  Bacteriology,  Vol.  68,
             (195*0.
 3.   Brochardt, J. A. and Azad,  H. A.,  "Biological  Extraction  of  Nutri-
      ents" Presented at 40th Annual Meeting Water  Pollution  Control
      Federation, New York,  (October 1967).

 4.   Harold,  F. M., "Inorganic  Polyphosphates  in Biology:  Structure,
      Metabolism, and Function"  Bacteriological  Reviews,  Vol. 30,  No. k,
      p. 772 -79^, (December  1966")

 5-   Menar, A.  B., and Jenkins  D., "The Fate of Phosphorus in  Waste
      Treatment  Process:  The Enhanced  Removal  of Phosphate by  Activated
      Sludge.",  Presented at 24th  Purdue Industrial  Waste  Conference,
      Purdue University, Lafayette,  Indiana, May 6-8, 1969.

 6.   Ferguson,  J.  F. , Stumm, W. ,  Jenkins,  D. "Calcium  Phosphate Precipi-
      tation in  Wastewater Treatment Processes", Presented at 3rd  Joint
      Meeting  of the American Institute  of  Chemical  Engineers and
      Institute  Mexicano De  Ingenieros  Quimicos, Denver,  Colorado, August
      30 - September 2, 1970.

 7.   Vacker,  D. , Connell, C. H.,  Wells,  W. N.,  "Phosphate Removal through
      Municipal  Wastewater Treatment at  San Antonio, Texas", WPCF, Vol. 39,
      No. 5, P.  765.

 8.   Public Statement by Sewerage Commission of the City of Milwaukee,
      for the  Lake  Michigan  Conference  on March  31 >  1970.

 9.   Witherow,  Jack L. , "Phosphorus Removal by  Activated  Sludge," Proceed-
      ings of  the 24th Industrial  Waste  Conference,  Purdue University,
      Lafayette,  Indiana (1969).

10.   Bargman, R. D. , Betz,  J. M.,  and  Garber, W. F. , "Nitrogen Phosphate
      Relationships and Removals  Obtained by Treatment  Processes at the
      Hyperion Treatment Plant,"  Presented  at 5th International Water
      Pollution  Research Conference, San Francisco,  California, July-
      August,  p. 817.

11.   Wells, W.  N., "Differences  in Phosphate Uptake Rates Exhibited by
      Activated  Sludges," Journal  of the Water  Pollution  Control Fed-
      eration, WPCF, Vol. 41, No.  5, P.  765.
                           93

-------
12.   Alarcon, G. 0., "Removal of Phosphorus from Sewage."  Master's  Essay,
      The Johns Hopkins University, Baltimore, Maryland, (1961).

13.   Scalf, M. R., Pfeffer, F. M., Lively, L. D., Witherow J.  L., Priesing,
      C. P., "Phosphate Removal at Baltimore, Maryland," Journal of Sanitary
      Engineering Division, ASCE, Vol. 95, No. SA5, Process Paper 6817,
      P. 817.

14.   American Public Health Association "Standard Methods for  the Examina-
      tion of Water and Wastewater",  12th Edition, 1965.

-------
                            SECTION VII

                       LIST OF PUBLICATIONS
                PRODUCED AS A RESULT OF THIS STUDY

1.   MMbury, W. F., Doll, F. L., Stack, V. T., Zaleiko,  N. S., "A  Compre-
     hensive  Instrumentation System for Simultaneous Monitoring of  Multi-
     ple Chemical Parameters in a Municipal Activated Sludge  Plant,"
     presented at the  Instrumentation  Society  of America  Conference,
     Pittsburgh, Pennsylvania, (May 26, 1970).

2.   Milbury, W. F., Stack, V. T., Bhatla, M.  N., "Effect of  Dissolved
     Oxygen on Phosphorus Removal in Municipal Activated  Sludge Treat-
     ment," presented at 3rd Joint Meeting of  the American  Institute of
     Chemical Engineers and Institute  Mexicano De Ingenieros  Quimicos,
     Denver, Colorado, September 2, 1970.

3.   Milbury, W. F., McCauley, D., Hawthorne,  C. H., "Operation of  Conven-
     tional Activated Sludge for Maximum Phosphorus Removal," presented at
     the ^3rd Annual Meeting, Water Pollution  Control Federation, Boston,
     Massachusettes, October 6, 1970.

4.   Milbury, W. F., Doll, F. L., Stack, V. T., "Simultaneous Determina-
     tion of Total Phosphorus and Total Kjeldahl Nitrogen in  Activated
     Sludge with the Technicon Continuous Digester System", presented
     at 1970 Technicon International Congress, New York Hilton Hotel,
     New York, November 3, 1970.
                                 95

-------
Appendix

   A
                           SECTION VI I I

                            APPENDICES
DATA TABLES	     99
  Table A-l:    Activated Sludge Plant Flowmeter
               Calibration Tests - Lithium Salt
               Dilution Tests	     99
  Table A-2:    Summary of Dai ly Analyses	    100
  Table A-3:    Weekly Composite Metal Results for
               Common Primary Effluent	    110
  Table A-4:    Summary of Plant Samples	    117
  Table A-5:    Average Test Period Results	    12k
  Table A-6:    Prof i le Analytical Results	    125
  Table A-T:    Total  Inorganic Carbon Results	    132
  Table A-8:    Characteristics of Wastewaters from
               Sludge Handling Operations	    153
  Table A-9:    Air Supply Rates for Rapid Dissolved
               Oxygen Va r i a t i on Tes t	    13^
  Table A-10:  Summary of Oxidation Reduction
               Potential Results	    135
  Table A-ll:  Laboratory Batch Study on Effect of
               Suspended Solids on Phosphorus
               Remova 1	    136
  Table A-12:  Laboratory Data for Tests to Maintain
               Phosphorus Remova 1	    137
  Table A-13:  Observation of Metal Variations with
               Time	    138
  Table A-l^:  Phosphorus Removal Accountability by
               Theoretical Metal and Biological
               Requirements	    139
  Table A-15:  BOD of Wastewater Samples - Normal and
               Nitrification -  Inhibited Values	

A COMPREHENSIVE  INSTRUMENTATION SYSTEM FOR SIMULTANEOUS
MONITORING FOR MULTIPLE CHEMICAL PARAMETERS  IN A
MUNICIPAL ACTIVATED SLUDGE PLANT	
  Introduction	
  Description of Monitoring System	
  Discuss ion	
  Monitoring Conclusions	    150
  Figure B-l: Physical Location of Sampling Points...    152
  Figure B-2: Flow Diagram of Complete Sampling and
              Analytical System	,	    153
  Figure B-3: Aeration Tank Sampling Point	
  Figure B-k: Sample  Switching and Collection System.
  Figure B-5: Automatic Analyzer Systems	    154
  Figure B-r6: Typical Ortho-phosphate and Ammonia
              Nitrogen Output Curves	    155
                                97

-------
Append ix
            Figure B-T:

            Figure B-8:
            Figure B-9:

            Figure B-10:
            Figure B-ll:
            Figure B-12:
            Figure B-13:
Typical COD and Combined Nitrate-
Nitrite-Nitrogen Output Curves....
Total Carbon Output Curves	
Total Kjeldahl Nitrogen and Total
Phosphorus Output Curves	
Dissolved Oxygen Output Curves....
Typical Turbidity Output Curves...
Typical pH Output Curves	,
Phosphate Removal in Full-Scale
Activated Sludge without Chemical
Add i t ion	
                                          Page
155
155

156
156
157
157
                                                                     158

-------
                                                             Table A-l

                                                Baltimore Phosphate Removal Study

                                       Activated Sludge Plant Flowmeter Calibration Tests
                                                   Lithium Salt Dilution Tests

                                              Lithium Salt Dilution Tests
VD
Process Flow

No. 1 Return Sludge
No. 2 Return Sludge
No. 1 Primary Effluent
No. 2 Primary Effluent
Total Secondary
Effluent
Tracer
Concentration
mg/L
39,000
39,4oo
41,200
39,200
81,000
Feed
Actual Meter Readings
Addition Downstream
Rate Tracer Concentration Computed Rate
gpm
0.108
0.104
0.220
0.'201
0.228
mg/L
3.68
3.60
2.88
2.36
l.6o
gpm
1,140
i,i4o
3,i4o
3,330
11,500
mgd
1.64
1.64
4.53
4.79
16.6
Chart
Read! ng
mgd
1.65
1.60
1.58
1.60
4.55
'4.40
16.5
21.0
Meter
Total izer
mgd
1.70
1.72
1.45
1.51
3.93
3.80
19.8
Meter
Location

Inlet
Outlet
Inlet
Outlet
Inlet
Inlet
Inlet1
Outlet2
   10btained by adding two primary effluent feed  rates and subtracting the wasting rate.

   20bserved at Bethlehem Steel secondary effluent reuse flowmeter.

   Note:  These tests were done on 5/28/69 and 6/3/69.  All meters were of the Venturi type.

-------
                                                                                               Table A-2
                                                                                    BALTIMORE  PHOSPHATE REMOVAL  STUDY
                                                                                        Sunmary  of Daily Analyses

                                                                                                 Date - 1969
8

Flow (MGD)
SE-I
SE-.'1
RS-I

X1 s- 1
X' 5-2
TOT. P. (mg/L;
PE
AT-I
AT-?
RS-I
RS-2
SE- 1
SE-2
TOT.KN (mg/L)
AT
AT~2
RS-1
RS-2
SE- 1
SE-2
SS (mg'L)
PE
— r/^i, —
>• s
e^T
1.7
1.8
. 1 1
.10
9.0
5!*.0
50.0
115.0
83.0
2.0
1.0
13.0
7* o
(J . u
69.0
122.0
1 10.0
9.0
9.0
128
AT- 1 2300
AT-2 2250
RS-I II 100
RS-2
SE-I
SE-2
PERCENT VSS (VSS/SS)
PE
AT-1
AT-2
SVI
AT-I
AT-?
TEMP. °r.
PE
SE-I
SE-?
800, Img/L)
PE
SE-I
SE-2
TOC (mg/LJ
PE
SE-I
SE-2

10
13

73
73
103
100
67
67
6T


_

_
-
6/25
8.0
8.T
1.8
1.8
.18
.18



_
_

_



_



116
2295
2105
_
2
5

T2
73
lilt
ICC
67
67
67
165
9
7

_
-
	 5/25 	
7.3
8.7
1.8
1.8
.18
.18

_

_
_

_


_
_
_
_
-
119
2260
22UO
_
9
11

_
-
105
107
66
66
66
250
31*
38

_
-
fc/27
8.0
8.7
1.8
1.8
O.I
0.1

_
_
_
_
_
-


_
_
_
_
-
133
2185
2205
_
5
10

„
-
102
105
69
TO
TO

_
-

„
-
6/30
8.8
8.9
1.9
1.9
O.I
O.I

_
_
_
_
_
-

_
_
_
_
_
-
206
2090
2070
8650
7520
_
6
66
73
Tit
101
109
68
68
68
.
_
-

_
-
7/1
8.7
8.8
1.9
2.0
0.18
0.09

89*
103
>200
>200
_
-

100
130
> 200
> 200
_
-
11*9
2125
2080
1011*0
8520
6
7
51
73
74
100
112
67
68
68
21*0
23
26
.
_
-
7/2
8.6
8.8
1.8
2.0
0.12
0.09
II. 0
85
76
>200
>200
6.0
13.0
27.0
110
120
>200
>200
13.0
15.0
132
21TO
2160
8620
851*0
10
11
61
7k
75
101
119
69
70
70
300
19
32
120
20
30
7/3
8.6
8.8
1.8
1.9
0.08
O.ll*

_
_
_
_
„
-

„
„
_
_
_
-
128
2260
2210
-
10
19

_
-
100
117
69
69
69
.
_
-
100
25
35
7/7 _
8.0
8.6
1.9
1.9
0.07
0.08
13.0
82
77
>200
>200
i*.o
3.0
30.0
122
128
>200
>200
22.0
18.0
121
2080
2030
91*80
9100
2
11
68
7k
73
89
105
68
68
68
220
21*
21*
115
25
25
	 7/B
8.0
8.5
1.8
1.9
.OT
.OT
15.0
61
TO
>200
>200
13.0
15.0
28.0
126
111*
>200
>2IO
20.0
18.0
107
2105
2060
9980
9930
19
22
81*
7k
78
112
123
69
69
69
220
32
?6
100
25
30
7/9 .
8.0
8.9
1.8
1.9
0.06
0.05
15.0
TO
73
>200
^•200
6.0
9.0
25.0
121*
121*
>200
>200
12.0
13.0
111*
2220
2100
I05l*0
11320
25
30
67
71*
75
125
139
68
69
69
215
20
33
85
20
30
	 TTTcr-
8.8
8.9
1.8
1.8
O.OT
0.11
13.0
63.
52.
>200
>200
10.0
8.0
28.0
122
128
>200
>200
18.0
22.0
92
2300
2290
10TOO
II 120
15
S3
77
75
77
111*
157
68
70
TO
220
2k
32
.
.
-
	 77TT—
8.7
9.0
1.8
1.8
0.10
0.11
„
-
-
-
-
-
-
_
-
-
-
-
-
-
118
2300
2310
-
13
18
.
.
-
119
|1*8
69
70
70
_
-
-
_
-
-
l/\k
10. 1
9.5
2.0
1.9
O.OT
O.OT
12.0
93
81*
300
27k
< 1.0
6.0
30.0
126
136
220
220
22.0
20.0
133
1980
1920
11UOO
10920
17
11
_
7k
76
85
86
69
69
69
190
18
21
_
-
-
77T5
8.6
7.8
2.0
2.0
0.06
0.06
12.0
71*
5k
250
2l*O
16.0
18.0
25.0
130.
131*.
210.
210.
18.
19.
85
2130
2160
10250
10820
25
26
59
75
78
105
107
TO
70
70
210
23
31*
21*5
115
130

-------



















1— I
0
H




























Flow (MGD)
SE-1
SE-2
RS-1
RS-2
X's-1
X's-2
TOT. P. (mg/L)
PE
AT-1
AT-2
RS-1
RS-2
SE-1
SE-2
TOT.KN (mg/L)
PE
AT-1
AT-2
RS-1
RS-2
SE-1
SE-2
SS (mg/L)
PE
AT-1
AT-2
RS-1
RS-2
SE-1
SE-2
PERCENT VSS (VSS/SS)
PE
AT-1
AT-2
SVI
AT-1
AJ-2
TEMP. F.
PE
SE-1
SE-2
BODS (mg/L)
PE
SE-1
SE-2
TOC (mg/L)
PE
SE-1
SE-2

7/16

9.0
9.3
2.0
1.8
o.ll
0.10

14.0
76
48
153
140
11.0
12.0

38.0
150
152
210
20k
22.0
24.0

133
2370
2250
10630
10950
12
1U

.
77
82

112
108

70
71
71

216
27
35

285
120
135

7/17

8.8
9.0
2.0
2.0
0.15
0.15

13.0
66
39
220
180
8.0
10.0

32.0
148
130
210
210
22.0
20.0

122
2450
2220
10120
9760
49
19

-
78
80

115
97

70
71
71

183
31
32

265
130
135

7/18

8.8
9.0
2.0
2.1
0.18
0.19

_
_
_
_
_
_
_

_
-
-
_
-
_
_

127
2330
2048
-
-
29
34

-
-
-

107
99

70
72
72

-
_
-

250
110
135

7/21

8.9
9.1
2.2
2.2
0.15
0.09

_
_
_
_
„
_
_

_
-
_
_
-
_
_

97
1850
1940
_
-
23
25

-
_
-

82
87

69
71
71

-
-
_

285
120
120

7/22

8.8
9.0
2.2
2.2
0.16
0.11

11.0
78
54
278
184
5.0
12.0

22.0
120
135
220
218
17.0
22.0

99
2130
2070
9420
9630
15
7

38
77
80

87
96

69
70
70

105
36
36

155
105
120
Table A-2
(continued)
BALTIMORE PHOSPHATE REMOVAL STUDY
Summary of Dally Analyses
Date - 1969
7/23

8.8
9.1
2.2
2.2
0.16
0.10

10.0
70
56
260
158
61.0
8.0

28.0
119
151
218
216
14.0
18.0

94
2090
1940
13660
8950
18
17

_
75
79

82
87

69
70
70

159
19
26

-
125
145
7/24

9.0
9.0
2.1
2.1
0.12
0.11

14.0
73
48
245
162
<\.o
8.0

27.0
123
114
215
214
16.0
21.0

115
2050
1940
7550
8510
25
25

62
75
78

50
53

68
69
69

150
20
54

205
90
120
7/25

9.0
9.0
2.1
2.1
0.10
0.11

_
_
_
-
_
_
_

_
-
-
_
-
-
_

104
2040
1930
-
-
23
24

_
_
.

87
68

-
-
_

-
-
-

255
100
125

7/29

8.0
9.0
2.4
2.2
.13
.16

13.0
106
78
238
216
_
_

29.0
145
141
>200
^200
18.0
18.0

101
2130
1650
9830
8710
9
13

_
76
73

49
58

69
69
69

96
4
5

165
70
80

7/30

8.7
9.2
2.4
2.2
.15
.17

10.5
105
74
274
246
4.0
7.0

30.0
138
122
274
246
18.0
18.0

114
2220
1660
9411
8192
3
4

_
71
76

90
76

70
71
71

204
12
21

270
105
110

7/31

8.6
9.2
2.4
2.2
.16
.17

11.0
98
78
280
240
12.0
18.0

32.0
170
126
>200
>200
18.0
18.0

114
2110
1665
9160
9030
20
19

76
77
79

95
76

71
71
71

230
16
20

245
90
105

a/it

8.1
7.2
2.2
2.2
.14
.23

8.0
92
62
-
,.
<: l.o
2.0

28.0
148
107
_
-
14.0
15.0

127
2150
1580
_
-
5
15

_
75
76

92
52

_
_
_

138
5
15

95
20
30

8/5

7.9
6.7
2.2
2.2
.13
.21

9.0
92
65

240
1.0
2.0

23.0
145
108
308
332
16.0
17.0

136
2140
1530
6753
7493
7
14

_
76
79

97
51

_
_
_

160
9
16

130
35
35

8/6

7.4
6.4
2.2
1.6
.12
.22

10. 0
96
67
226
200
2.0
2.0

28.0
121
75
220
216
15.0
I4.o

no
2090
1400
9304
7732
7
10

_
74
82

103
55

_
_
_

150
10
7

145
35
35

8/7

7.0
5.5
2.0
1.6
.13
.22

10.0
80
58
310
260
6.0
4.0

23.0
145
61
410
380
13.0
13.0

106
2150
1360
_
_
20
15

_
_
_

106
51

—
—
_

165
13
12

120
35
35

-------
           Table A-2
          (conti nued)

BALTIMORE PHOSPHATE REMOVAL STUDY
    Suimary of Dally Analyses

             Date - 1969
B/B
FLOW (HSO)
SE-I 7. It
SE-2 5.6
RS-1 2.0
RS-2 1.6
X'5-l .15
X'S-2 .11
TOT. P. (mg/L)
PE
AT-1
AT-?
RS-1
RS-2
SE-1
SE-2
TOT.KN (mg/L)
PE
AT-1
AT-2
RS-1
(-" RS-?
O SE-I
ro SE-2
SS (mg/L)
PE |l*3
AT- 1 221*0
AT-2 |1*05
RS-I
RS-2
SE-I 11
SE-? 11
PERCENT VSS ( VSS/SS)
PE
AT-I
AT-2
SVI
AT-I 101
AT-2 51*
TEMP. °F.
PE
SE-I
SE-2
BOD., (mg/L)
PE
SE-I
SE-?
TOC Img O
PE 125
SE-1 35
SE-2 35
B/ll

8.1*
6.7
2.2
2.0
.09
.05

7.0
89
87
160
15U
< 1.0
< 1.0

21
ll*9
135
21*5
132
15
17

133
2090
1650
9191
8315
11
8

_
73
72

93
61
-
-
-

138
11
8

90
25
20
8/12

8.2
6.3
2.1
2.1*
0.08
0.21

9
98
92
.
-
tl.O
2.0

21
163
11*5
21*2
202
13
15

117
2175
171*0
91*71*
6886
11
13

_
72
71

90
72
-
-
-

170
10
7

110
20
25
8/13

8.2
6.5
1.6
1.9
10
.57

II
95
71*
250
200
<1.0
< 1 .0

21
155
110
260
250
13
13

121
2210
1560
12960
651*0
3
2

_
77
72

88
77
-
-
-

190
15
8

120
35
35
8/|l*

8.1
6.5
1.3
1.2
.07
.33

11
107
96
250
168
< 1.0
7.0

22.0
17U
156
300
250
13
15

126
2010
1830
11*850
1*580
26
17

_
76
76

66
86
-
_
.

185
13
10

110
55
50
8/15

8.0
6.6
1.5
1.7
_
_

.
-
.
_
-
-
„

.
_
_
-
-
-
-

|l(3
21*50
1010
15
31

_
-
-

81
79
70
72
72

_
-
-

_
-
-
8/18

7.7
7.1
2.0
1.1
.08
.65

9.5
108
78
388
216
2.0
3.0

22
125
78
1*51*
236
17
18.5

123
1980
1020
9200
3970
5
12

_
65
61

101
115
70
71
71

130
9
8

70
20
30
B/19

7.8
6.7
2.0
2.0
.10
.08

9
98
1*8
312
161*
3.0
U.5

23
106
63
1*00
212
17
15.5

133
2070
910
8880
3650
18
11*

_
72
73

95
125
71
71
71

155
9
8

80
35
25
8/20

6.1
U.I
2.2
2.0
.16
.05

6.8
102
52
232
160
1.5
2.0

20.5
117
70
301*
200
16
18

113
2085
1080
7273
U399
11
11

_
70
73

109
115
70
70
70

100
9
7

85
30
35
B/21

8.1
6.9
1.8
2.0
o.iU
0.00

11*5
9>*
72
261*
201*
1.0
1.5

17.5
107
90
3UU
272
13
1U.5

IU9
2090
1530
8335
6207
6
11

_
71
70

119
133
69
70
70

60
15
11

100
25
35
B/22

8.1
7.1
1.8
2.0
0.15
0.00

_
_
_
_
_
_
_

_
_
_
_
-
_
_

126
211*0
1670
10
10

_
_
-

125
153
70
70
70

_
_
_

_
_
-
8/25

8.5
9.3
2.0
2.0
.19
.03

8.0
136
lUo
252
260
1.5
2.0

20
128
135
250
275
13
16

139
1980
2350
9630
11022
1
9

_
70
70

139
191
70
70
70

180
11
20

85
20
20
8/26

8.3
9.5
1.9
2.5
.12
.02

7
106
138
286
292
1.0
1.5

26
101*
125
270
290
10
12.5

167
I9UO
2600
9311
I17U2
6
10


71
67

13!*
229
71
71
71

190
10
17

180
35
1*5
B/27

8.0
9.1
1.8
3.6
.08
.02

7.5
128
160
261*
286
0.5
1.5

19.5
98
IU8
280
290
IU
IU

130
20UO
3110
907U
9517
12
8


71
71

139
23U
70
70
70

195
9
9

1U5
25
35
B/2B

6.3
6.U
1.8
3.6
.IU
.08

6.6
137
162
250
272
1.0
1.5

23
120
160
238
276
9.5
11.0

lUU
231*0
3670
7316
8858
2
5


68
67

lUO
237
70
71
71

-
10
13

155
20
30

-------
           Table A-2
          (conti nued)

BALTIMORE PHOSPHATE REMOVAL STUDY
    Summary of Dally Analyses

             Date - 1969

FLOW (MGD)
SE-1
SE-2
RS-1
RS-2
X's-1
X's-2
TOT.P. (mg/L)
PE
AT-1
AT-2
RS-1
RS-2
SE-1
SE-2
T01.HN (mg/L)
PE
AT-1
H AT-2
0 RS-1
^ RS-2
SE-1
SE-2
SS (mg/L)
PE
AT-1
AT-2
RS-1
RS-2
SE-1
SE-2
PERCENT VSS (VSS/SS)
PE
AT-1
AT-2
SVI
AT-1
AT-2
TEMP. f.
PE
SE-1
SE-2
BOD5 (ng/L)
PE
SE-1
SE-2
TOC (mg/L)
PE
SE-1
SE-2
a/ 29

6.6
5.2
1.8
3.6
.20
.15

-
_
_
_
_
-
-

_
_
_
_
_
_
_

156
2770
5620
-
-
2
23

_
-
-

125
211

JO
71
71

-
-
-

165
55
40
9/2

6.2
6.5
1.9
2.5
.17
.08

10. 4
120
134

528"

2.0

24.6
152
160
_
1*20
5.6
5.8

168
2470
2950
-
8149
15
16

_
68
68

219
255

71
71
71

140
20
25

95
-
-
9/3

6.9
7.1
1.9
3.0
.25
.05

9.0
126
144
_
_
2.0
1.4

21.4
150
158
260
440
6.0
7.2

198
2250
2790
4279
9401
5
11

_
66
65

226
290

70
70
70

-
-
-

105
-
15
9/4

8.1
6.5
1.8
5.1*
.20
.15

7.5
102
146
556
560
2.0
2.5

25
136
188
440
416
6.4
7.8

191
2250
5220
9441
8515
12
12

_
62
65

144
279

70
70
70

-
-
-

95
10
20
9/5

9.0
4.0
1.8
3.8
.22
.72

-
_
_
_
_
-
-

_
-
_
_
_
-
-

161
2150
3230
-
.
3
2

-
_
-

158
271

70
70
70

-
-
-

105
15
10
9/B

6.3
6.1
1.9
1.6
.13
.19

15.2
84
100
284
296
5.5
2.0

50
155
165
456
460
15.0
11.6

147
2075
2450
8009
9158
5
11

_
67
66

195
252

70
70
70

173
58
27

65
10
5
9/9

9.4
4.5
1.9
1.6
.17
.21

13.8
85
96
284
264
6.8
2.4

28
165
165
460
440
19.0
8.8

187
2180
2560
10625
8711
6
2

_
68
66

158
191

69
69
69

192
48
52

85
55
10
9/10

9.0
4.4
1.8
1,6
.17
.21

14.6
101
98
180
200
4.0
2.0

29
170
144
240
500
15.5
7.6

164
2560
2190
12050
8548
6
2

..
72
68

183
195

70
70
70

580
45
55

85
25
10
9/1 1

9.0
4.5
1.8
1.6
.17
.22

11.5
93
97
330
296
2.6
1.0

28.5
164
160
480
268
10.2
3.5

182
2310
2120
10150
7842
2
6

.
71
72

279
159

70
70
70

180
23
30

_
-
-
9/12

8.9
4.3
1.8
1.3
0.22
0.08

-
_
_
_
-
-
-

_
-
_
_
_
-
_

183
2460
2050
_
_
10
5

_
_
-

262
179

69
68
68

-
_
_

_
-
-
9/15

7.8
9.0
1.9
2.7
.22
0.05(

13.2
126
110
225
205
-
-

26
170
149
580
564

6.4

171
2110
2010
9390
7150
_
.

_
74
79

227
559

70
71
71

560
33
21

_
5
10
9/16

7.7
8.7
1.9
2.9
.15
.29

12.4
105
106
310
528
-
3.0

26.5
160
166
460
470
15
15.4

160
2260
2370
9347
9081
10
11

_
71
70

249
569

70
70
70

297
38
26

_
15
20
. 9/17

8.4
9.5
1.9
2.0
.14
.56

10.5
103
90
564
296
2.2
2.0

24.5
165
138
480
440
8.4
9.0

196
2250
1850
9514
8475
2
4

_
69
73

205
290

71
71
71

157
10
9

125
5
10
5/18

8.7
11.7
1.9
2.0
.24
•31

11.2
100
81
364
54o
3
2

28.5
160
133
488
480
15.2
10.5

203
2240
1730
9923
9966
14
13

—
70
74

161
181

68
70
70

165
14
10

110
5
20
9719

8.7
11.7
1.8
2.5
.22
.21

_
_
_
-
.
-
-

_
.
.
-
_
-
-

202
1440
1990
_
_
12
10

_
_
_

153
158

68
68
68

_
_
_

100
15
30

-------

FLOW fMGD)
SE-I
SE-.''
RS-I
RS-2
X'S-I
X's-2
TOT.P (mg/L)
PE
AT-I
AT- 2
RS-1
RS-2
SE-I
SE-;J
TOT.KN (mg/L)
PE
AT-I
AT- 2
RS-I
RS-2
SE-1
5E-J
SS (mg'L)
PE
AT-I
AT- 2
RS-I
RS-2
SE-I
SE-.:
PERCENT VSS (VSS/SS)
PE
AT-1
AT-0
SVI
AT-I

TEMP. F.
PE
SE-1
SE-J
BOB, r^ L)
PE
SE-1
SE-2
TOC (mg'L)
PE
SE-I
st-?

9/22

7.V
f,.o
.'.1
f' . 2
.06
.66

' ' .5
M
')!•
296
236
1.5
1.0

• '7. 5
IIV
121.
560
,'80
1V.6
15.0

179
2OOO
2250
8059
6630
11
9

_
68
70

159


67
68
68

15V
20
16

95
15
15

9/23

7.3
6.2
2.0
2.1
.11
• V5

9.8
93
68
228
152
1.8
1.0

31
101
7V
2VO
168
16.0
15.V

173
23Vo
1760
9VJ7
591V
II
10

-
72
7V

188
200

67
68
68

225
22
10

100
20
20

9/2V

7.3
6.3
2.0
2.2
.2V
.10

9.8
82
78
26V
196
2.3
1.0

27
106
82
320
232
15
13.2

161
23 VO
1750
8971
627V
8
6

_
7V
71

279
218

67
_
68

220
37
19

105
20
20
Table A-2
( cont i nued)
BALTIMORE PHOSPHATE REMOVAL STUDY
Summary of Dally Analyses
Date - 1969
9/25

6.0
6.3
2.0
2.2
.V5
.VO

_
_
_
_
_
-
-

-
_
_
_
_
_
-

155
2210
1870
_
-
19
9

-
-
-

253
205

67
.
68

-
-
.

100
25
30
9/29

9.9
6.0
2.0
2.0
.08
.09

12.8
108
100
320
273
1.0
0.5

28. V
116
12V
V20
355
17.5
19.2

165
2005
1680
7726
633V
V
6

-
72
72

153
16V

67
-
67

57
16
9

70
10
15
9/50

9.7
6.0
2.0
2.0
.13
.15

13.0
118
106
326
320

1.5

-
150
1VO
V53
VOO
-
-

205
2150
1930
9361
6986
10
6

-
71
72

209
195

68
-
68

IIV
19
V

100
20
20
10/1

10.0
6.2
2.1
2.0
.19
.13

_
86
98
326
320
-
-

-
12V
136
V80
373
-
-

178
2170
2060
9867
7103
12
11

-
72
72

222
187

67
-
68

135
19
11

105
20
20
10/2 10/3

9.9 9.6
6.0 5.2
2.0 2.0
1.9 1.9
.29 .23
.19 .2V

- -
76
90
286
266
-
-

- -
135
136
V80
326
-
-

209 168
2280 2290
2130 1970
10906
7676
7 12
5 6

- _
68
69

2W 286
212 206

67 68
_
68 68

96
26
11

105
25
25

10/6

10.1
6.0
2.0
2.0
.IV
.IV

_
_
-
-
-
-
-

-
_
_
-
-
-
-

136
1660
1690
_
_
5
5

-
-
-

IV6
178

66
_
65

_
_
.

125
35
25

10/7

10.8
5.7
2.0
2.0
.15
.IV

10.8
91
10V
512
268
1.5
2.V

15
81
78
328
22V
5.V
7.0

1V8
1805
1760
8928
60V7
8
V

_
71
7V

17V
2V9

66
_
65

178
56
19

90
10
10

10/5

10.2
6.0
2.0
2.0
.19
.19

9.8
72
86
252
220
3.0
1.5

8.V
70
72
268
18V
8.2
5.6

158
1750
1790
9550
631V
10
9

_
75
69

207
2V7

66
_
66

150
19
16

125
10
15

10/9 10/10 10/13

11.5 10,6 9.T
5-5 7.5 9.0
2.0 2.0 J.O
2.0 2.0 2.0
.18 .2V .IV
.IV .15 .OS

- - _
- - _
-
- - -
-
- _ -
-

_ _
-
- - -
- - -
- _ -
_ _ -
- - -

178 160 iVl
1970 2170 2030
1850 1950 2010
_
- - -
5 12 11
7 10 9

- - -
_ _ -
.

228 210 172
325 3°5 376

66 65 66
_
66 66 66

. - -
, - -
- - -

125
15
25

-------
Table A-2
(continued)
BALTIMORE PHOSPHATE REMOVAL STUDY
Summary of Dally Analyses
Date - 1969

FLOW (MGD)
SE-1
SE-2
RS-1
RS-2
X's-l
X's-2
TOT. P. (mg/L)
PE
AT-I
AT-2
RS-1
RS-2
SE-I
SE-2
TOT.KN (mg/L)
PE
AT-1
H AT-2
S RS-'
RS-2
SE-1
SE-2
SS (mg/L)
AT-1
AT-2
RS-1
RS-2
SE-1
SE-2
PERCENT VSS (VSS/SS)
PE
AT-1
AT-2
SVI
AT-1
AT-2
TEMP. °F.
PE
SE-1
SE-2
BOD5 (mg/L)
PE
SE-1
SE-2
TOC (mg/L)
PE
SE-1
SE-2
10/14

9-1
9-0
2.0
1-5
.16
.11

10.5
108
102
256
258
1.2
2.8

514.
125
122
400
400
16.8
17.0
146
2030
2010
9814
10746
21
24
62
73
76

.
-
67
_
67
156

6
155
30
30
10/15

9-0
9-3
2.1
1.1
.17
.17

10.4
104
88
248
260
0.5
1.2

40.0
130
116
390
410
18.2
17.8
201
2300
I960
10743
13144
12
12
62
71
72

194
228
65
_
65
189
6
9
155
35
35
10/16

8.6
9.6
2.0
1-3
• 23
.10

9.5
122
96
250
256
.5
.8

32
145
125
390
415
19.4
16.6
136
2330
1980
10809
9284
16
20
59
71
72

200
217
65
_
66
171
3
5
145
35
35
10/17

8.6
9-5
2.0
1.8
.19
.12

10
122
125
288
296
1.2
1.0

24
152
150
360
420
17.0
12.6
148
2270
2170
9707
11998
11
6
56
69
71

153
168
65
_
64
195
2
7
130
30
20
10/20

8.3
9-5
2.0
2.0
.09
•09

13.2
79
80
250
280
2.0
0.8

38
133
124
210
228
21.2
20.8
]54
1650
1690
7213
7509

.
80
76
77

114
107
66
_
64
96
6
4
.
15
10
10/21

8.5
8.0
2.0
2.0
.18
.27

11.9
64
73

256~
19.5
3.6

36
128
122
190
220
25
25
168
1750
1810
-
-
18
5

-
-

117
103
66
-
65
120
22
15
105
20
20
10/22

9.4
9.8
2.0
2.0
.20
• 19

12.0
59
58
182
146
2.4
25.0

29.4
128
1»*3
200
188
18.2
27.0
15^
1850
I960
-
-
10
2

-
-

103
111
63
-
63
105
11
28
100
25
30
10/23

9.1*
8.4
2.0
2.0
.19
.17

10.4
59
42
235
184
2.2
9.8

1*3
130
122
234
220
24.4
29.3
172
1895
1870
-
-
16
28

-
-

94
119
61
_
62
150
9
38
95
25
^5
10/24

9.0
7.1
2.0
2.0
.18
.16

12.0

_
_
_
_
-

-
-
-
..
-
-
165
2010
1905
-
-
19
19

-
-

99
113
61
-
62
.
-
-
110
30
25
10/27

9-7
9-5
2.0
2.0
.16
.17

12.8
_
_
_
-
_
-

-
-
-
:
-
-
135
1770
1890
8392
6936
6
16
46
78
76

97
91
61
-
61
148
5
II
140
35
35
10/28

9-5
9-5
2.0
2.0
.11
.10

16.0
117
82
375
310
-
-

-
132
120
460
460
-
-
150
1870
1720
8392
6936
18
25
75
77
76

97
109
60
-
60
159
5
15
155
35
40
10/29

9-1
9-5
2.0
2.0
.17
.08

13-4
101
61
291
264
1.4
16.0

-
138
114
420
426
-
-
156
2040
1990
-
-
9
17
_
-
-

96
106
60
-
59
_
-
-
145
40
40
10/30

9.2
9-5
2.0
2.0
.27
.25

13-5
83
51
46o
288
-
-

-
56
52
390
249
-
-
158
2000
2095
-
-
14
26
_
-
-

102
105
60
-
61
211
12
25
120
35
40
10/31

8.0
9-5
2.0
2.0
•15
.26

-
-
-
-
-
-
-

-
-
-
_
-
-
123
2150
1898
-
-
11
21
_
-
-

105
101
60
-
60
229
10
25
130
30
40
'1/3

10.4
4.1
2.0
2.0
.14
. 14

8.2
106
102
310
300
0.8
1.2

22.4
155
132
340
350
20
20.8
139
1870
1955
9657
6950
10
23
76
74
72

107
84
62
-
62
132
5
9
,54
24
23

-------
                                                                                         Table A-2
                                                                                        (cont i nued)
                                                                              BALTIMORE  PHOSPHATE  REMOVAL  STUDY
                                                                                  Summary of  Dally Analyses

                                                                                        Date -  1969

FLOW (MGD)
SE-I
SE-2
RS-I
RS-2
X's-l
X's-P
TOT. P. (mg/L)
PE
AT-1
AT-P
RS-I
RS-2
SE-I
SE 2
TOT.KN (mg/L)
PE
AT-1
AT-;'
RS-I
RS-2
SE-I
SE-2
SS (mg/L)
PE
AT-I
AT-2
RS-I
RS-2
SE-1
SE-.
PERCENT VSS (VSS/SS)
PE
AT-I
AT-2
SVI
AT-I
AT-."1
TEMP.
PE
SE-1
SE-2
BOD5 (mg/L)
PE
SE-I
SE-2
TOC (mg/L)
PE
SE-1
SE-;
n A

10.8
U.O
2.0
2.0
.16
.17

13-5
120
118
320
520
1.0
0.5

21
11*6
151*
350
286
17.6
22.6

IV*
1 980
I9t0
_
_
20
15

_
.
-

108
82

61
„
59

136
8
5

150
50
35
11/5

10.5
"*.5
2.0
2.0
.21*
.11*

15.2
120
116
315
280
0.5
0.5

29.6
11*6
|1*2
520
280
llt.l*
19.6

127
1920
2l80
_
-
II
15

_
-
-

125
90

60
_
60

171
7
6

125
50
35
11/6

10.6
14.. 5
2.0
2.0
• 23
.12

II
110
111*
276
270
.
-

20.2
110
111*
276
270
-
,.

156
1970
1870
_
-
10
17

_
-
-

121.
109

59
_
58

161
II
6

120
25
30
11/7

10.5

2.0
2.0
.22
.17

8.6
101*
120
295
280
0.1*
O.I*

_
11*1*
1U8
520
280
-
_

156
1970
1965

-
6
6

_
-
-

155
125

59
_
59

205
7
5

_
-

11/10

8.0
9.5
2.0
2.0
.1*7
.50

11.2
_
_
-
-
0.5
0.5

19.1*
_
_
_
_
18.0
17.2

|1*0
1770
1850
8125
7652
2
8

80
72
7!*

129
129

62
_
61

186
9
7

-
-

11/11

8.2
8.5
2.0
2.0
.20
.18

15.0

_
-
.
0.5
0.8

26.8
_
_
-

16.1*
16.5

IJl*
1730
1850
.
-
7
5

-
-
-

130
139

58
-
58

180
10
9

11*5
1*0
1*0
11/12

8.1*
8.3
2.0
2.0
.11*
.16

10.1*
_
_
-
-
0.6
5.2

22.1*
-
_
-
-
15.0
16.8

131
1875
1825
-
-
7
11

-
-
-

150
11*6

59
-
59

215
5
8

130
35
1*0
11/15

8.6
8.6
2.0
2.0
.15
.17

_
_
_
-
-
.
-

_
_
_
-
-
-
_

211
201*0
1910
-
-
11
|1*

-
-
-

126
11*1

59
_
59

-
-
_

180
1*0
1*5
ll/li*

8.1
9.3
2.0
2.0
. 16
.17

12.5
96
61
226
190
0.5
10. 1*

29.6
112
102
260
21*6
25.6
20.0

151
2180
19ltO
-
-
8
6

-
-
-

120
138

58
_
58

150
-
18

185
1*5
1*5
11/15

8.0
8.1*
2.0
2.0
.15
.15

-
_
.
-
-
-
-

_
-
.
-
-
-
-

11*0
2180
1900
-
-
13
10

-
-
-

115
139

56
_
55

-
.
_

175
50
60
11/16

8.3
8.5
2.0
2.0
.15
.15

_
_
_
-
-
-
-

_
_
.
-
-
-
_

107
201*0
191*0
-
-
17
17

_
-
-

120
132

59
_
57

-
_
_

li+o
1*0
1*0
11/17

8.3
9-5
1.9
2.0
.1*9
.26

11.6
116
101*
250
218
0.8
2.8

53.0
152
162
550
560
21.0
21*. 0

11*5
181*5
1920
-
-
12
10

-
-
-

112
139

58
_
57

-
.
_

H*5
30
35
11/18 11/19 H/PO

8.8 3.0* J.O +
8.7 J.O*' 3.0*
1.9 1-9 1.9
2.0 2.0 2.0
.18
.16

10.0
1 10
86
>225
>C25
2.8
-

31*. o
11*1*
151*
550
290
19.2
21.2

136 106 11*0
1900 1600 2021*
1910 2060 2090
8628
8368
3
10

61* - -
79
76

113 116 89
138 131 115

58 60 56
-
57 59 56

197
15
11+

160
35
1*5
Systems down 15 hours p«r day

-------
b
                                                                                                  Table A-2
                                                                                                 (contInued)
                                                                                      BALTIMORE PHOSPHATE REMOVAL STUDY
                                                                                           Summary of  Dally  Analyses
                                                                                                  Date -  1969
11/23
FLOW (MGD)
SE-1
SE-2
RS-1
RS-2
X's-1
X's-2
TOT. P. (mg/L)
PE
AT-1
AT-2
RS-1
RS-2
SE-1
SE-2
TOT.KN (mg/L)
PE
AT-1
AT-2
RS-1
RS-2
SE-1
SE-2
SS (mg/L)
PE 143
AT-1 2350
AT-2 1650
RS-1
RS-2
SE-1 15
SE-2 16
PERCENT VSS (VSS/SS)
PE
AT-1
AT-2
SVI
AT- I 120
AT-2 105
TEMP. °F.
PE 55
SE-1
SE-2 56
BOD5 (mg/L)
PE
SE-1
SE-2
TOC (mg/L)
PE
SE-1
SE-2
11/24

9.6
9-8
1.8
2.0
.27
.00

13.6
138
78

408
1.0
3.0

40.0
132
92
648
424
16.4
15.8

135
2254
1270
_
.
15
15

-
_
.

124
120

56
-
54

114
5
4

120
30
25
11/25

5.8
7.2
2.0
2.0
.13
.00

16.2
145
80
664
360
2.6
5-2

32.0
134
94
600
4oo
19.0
17.8

145
2435
1450
-
-
20
10

-
-
-

123
112

55
55
56

220
7
6

106
16
20
11/26

4.8
4.4
2.0
2.0
.11
.00

.
132
102
612
168
_
_

-
136
106
544
192
-
-

136
2025
1280
-
-
14
13

-
-
-

142
123

58
-
56

-
-
-

125
45
35
11/27

8.7
9.0
1.8
2.0
.15
0.0

-
-
-
-
-
_
-

-
-
-
-
-
-
-

117
2155
1475
-
-
13
16

-
-
-

131
123

54
-
54

-
-
-

160
45
40
11/28

8.5
9.0
1.8
2.0
• 33
.00

13.4
114
96
388
324
0.4
0.2

36.0
162
156
520
496
19.4
19.2

137
2075
1760
10606
6327
11
15

42
67
76

132
128

54
-
54

130
7
9

120
35
35
11/29

8.5
9.0
1-9
2.0
.14
.08

_
-
-
_
-
_
.

-
.
.
_
-
_
-

115
2025
2010
.
-
1
3

-
-
-

1 1 1
133

55
-
54

-
-
-

127
29
34
11/30

8.3
8.8
1.9
2.0
.20
.15

-
-
-
.
_
_
.

-
.
_
_
-
.
-

101
1990
1955

.
4
6

-
_
_

136
135

54
-
53

-
-
-

110
30
30
12/1

9.8
9.8
1.9
2.0
.26
.24

9.4
108
96
472
440
2.4
2.8

35.0
149
143
484
472
16.5
17.4

113
1890
1755
_
.
13
15

-
_
»

134
139

56
-
54

I4o
6
6

67
24
23
12/2

8.7
8.4
1.9
2.0
.14
.12

14.6
132
109
484
488
1.8
1.2

4o.o
188
163
500
516
14.8
14.2

177
2130
2010
.
-
19
16

-
_
.

151
14T

55
_
54

210
13
8

175
45
45
12/3

9-7
9-7
1.9
2.0
.31
.19

9-4
99
98
520
480
1.4
1.0

36.0
154
152
516
500
15-0
15.0

157
1940
1890
_
.
13
10

-
_
_

152
157

54
_
54

168
10
7

150
45
45
12/4

8.6
9-7
1.9
2.0
.26
.23

9.8
114
107
520
456
1.2
1.4

40.0
162
159
504
492
14.6
15.6

135
1930
2005
-
-
25
22

-
.
_

152
150

54
_
53

195
11
9

_
_
-
12/5* 12/6

8.0 o.o
9.0 14.8
1.9 0.0
2.0 4.4
.35 0.0
.20 .50

10.2
0
126
0
560
0
.8

29.2
0
186
0
532
0
17.2

126 110
1805 o
2180 2147
-
-
10 0
12 7

-
_
.

144 0
153 180

53 55
0
53 53

.
„
_

148
0
50
12/7 '

0.0
20.2
0.0
4.4
0.0
.30

8.2
0
102
0
592
0
1.6

28.8
0
148
0
530
0
16.2

86
0
1913
-
-
0
9

-
_
.

0
178

54
0
53

„
_
_

131
0
44
        •System No. 1 out of operation from 12/5/69 to 12/22/69

-------









H
O
00






















FLOW (MOO)
SE - 1
SE-:
RS-1
RS-2
X's-l
X's-?
TOT. P. (mg/L)
PE
flT 1
M 1 - 1
AT-?
RS- 1
RS-2
SE-I
SE-.'
TOT.KN (mg/L)
PE
AT-I
AT-;
RS - 1
RS-.'
SE- 1
SE-:'
SS (mg/L)
PE
AT- 1
AT-J
RS-,
RS-2
SE-I
SE-2
PERCENT VSS (VSS/SS)
PE
AT-I
AT-.'
SVI
AT-I
AT-."
TEMP.°F.
PE
SE- I
SE-2
BOO., (mg/U
PE
SE-1
SE-.'
TOO (mg L'l
PE
SE-1

12/8

0
20.2
0
U.U
0
.27
9-2
0
122
0
>300
Q
0.5
35.0
0
,58
0
> ^00

0
13.8
98
0
2070
0
8560
o
6

22
o
76

0
155
"5U
5 0
52
IV5
35 o
23
IUU
0

12/9
0
20.6
0
'o
.28
Q
IU2
0
296
0

0
IUO
o
> '.00
0

,01
Q
22UO
0
0
12

0


0
185
5U
0
52
168
0
,6
III
0

12/10
0
I9.U
0
0
.36
13.6
Q
IUU
0
726
0
1.3
26.1
0
198
o
7600
0
15.8
123
Q
2U20
0
10670
0
,2

79
0
77

0
187
5U
0
52
177
0
28
,09
0

12/11
0
17.0
0
U.2
0
-32
8.6
0
I51*
0
UTO
0
1.1
26.0
0
220
0
U80
0
12.8
118
0
2370
0
0
1U

0
-

0
,82
53
0
53
230
0
I,
106
0

12/12
0
16.8
0
U.I
0
.35
0
130
0
0
I.U
0
20U
0

0
16.2
,02
0
2190
0
0
,2

'o
-

0
108
53
0
53
177
0
13
IU6
0
BALTIMORE
Sumnta
12/13
0
It,. 6
0
u.o
0
• 33
0
0
0
-
0
0
_
0
-
98 o
2,00
Q

0
21

"o
-

0
,58
53
0
51
_
0
-
135
0
Table A-2
(continued)
PHOSPHATE REMOVAL STUDY
ry of Dai ly Analyses
Date - 1969
12/lU
0
16.7
0
U.2
0
• 23
11 .0
0
128
0
50U
0
2.8
22.0
0
20U
0
U90
0
22.0
109
20U5Q

"o
15

"o
-

0
160
53
0
5,
130
0
10
108
0
12/15
0
16.9
0
U.2
0
.22
10.6
0
126
0
510
0
U.6
28.0
0
202
0
U60
0
17.6
105 o
2,1*0
o

"o
12

"o
-

0
IUU
53
0
51
110
0
9
102
0
12/16
0
12.5
0
U.2
0
• 36
9.8
0
128
0
0
5.1*
25.0
0
199
0
U56
0
22.0
,06
2353 0

9727 0
13

70
7U

,58°
51
0
51
165
0
1U
in
0
12/17
0
8.3
0
3-U
0
.51
11.0
0
138
0
'325
0
o.U
25.0
0
20U
0
U28
0
18.0
85 o
2590

"o
6

"o
-

0
209
51
0
51
,86
0
8
118
0
12/18
0
7.5
0
0
-52
8.8
0
106
0
232
0
2.6
22.8
0
186
0
376
0
16. U
88
0
1830

0
5

"o
-

,U8°
52
0
52
200
0
7
112
0
12/19
0
7.6
0
u.u
0
15'°o
8,
0
101
0
11.6
27.0
0
,06
0
126
0
23.2
88
0
,U,0Q

"o
-

"o
-

,56°
51
0
51
_
0
-
115
0
12/20
0
7-9
0
U.7
0
.08
10.6
0
8U
0
115
0
7.2
27.0
0
,12
0
IUU
0
20.0
86
0
1U82
0

"o
-

"o
-

0
153
51
0
51
-
0

87
0
12/2,
0
7-9
0
U.6
0
.06
,5.6
90
0
128
0
6.0
25.0
1,9
0
160
0
20.8
^0
,750

"o
-

"o
-

0
,U7
52
0
50
-
0
-
98
0
12/22
0
7-9
0
U.8
0
.06
10.2
0
0
0
9.U
25.8
0
-
0
21.0
130
0
,965 Q
U280
o"
—
Tfl
1°
0
76

0
,7,
50
. 0
U9
-
0
"
79
o, 0
33
                        22
                                                            29
                                                                        22
                                                                                    19
                                                                                               23
                                                                                                           33
                                                                                                                        19
                                                                                                                                                19

-------
Table A-2
(continued)
BALTIMORE PHOSPHATE REMOVAL STUDY
Summary of Daily Analyses
Date - 1969 and 1970

FLOW (MGD)
SE-1
SE-2
RS-l
RS-2
X's-1
X's-2
TOT. P. (mg/L)
PE
AT-1
AT-2
RS-l
RS-2
SE-1
SE-2
TOT.KN (mg/L)
PE
AT-1
AT-2
RS-l
RS-2
SE-1
SE-2
SS (mg/L)
PE
AT-1 1
AT-2 1
RS-l
RS-2
SE-1
SE-2
PERCENT VSS (VSS/SS)
PE
AT-1
AT-2
SVI
AT-1
AT-2
TEMP. °F.
PE
SE-1
SE-2
BOD5 (mg/L)
PE
SE-1
SE-2
TOC (mg/L)
PE
SE-1
SE-2
12/23

5-7
6.0
2.0
2.0
0.1
0.1

-
-
_
-
_
-
-

-
-
-
-
_
_
.

110
,520
,610
_
-
-
_

_
-
-

184
175

48
48
48

-
-
_

74
15
16
2/12/70 2/13/70 2/27/70

8.5 8.5 8.0
9.0 9.0 8.5
2.0 2.0 2.0
2.0 2.0 2.0
-
-

13.8 7.0 16.5
105
- - -
_
..
6.6 2.1 .5
7.2 2.0 1.5

30.0 22.0 33.0
175
-
-
.
19.4 12.2 17.0
20.5 12.7 17-5

112 160 170
2,015 2,050 2,200
2,050 2,040 2,210
- _ -
-
- - -
- _ -

- _ -
76
-

120 108 126
110 105 124

- - _
- - -
_

-
_
-

-
_ _ -
-
2/28/70

8.5
8.5
2.0
2.0
-
_

18.0
88
„
34o
_
.5
2.5

320
142
-
505
,„
15.5
16.0

150
1,890
1,980
.
_
-
_

„
-
-

120
118

_
-
-

-
-
-

-
-
-
3/1/70

8.5
9.0
2.0
2.0
.
-

10.2
-
_
-
-
1.7
3.5

25.5
-
-
-
_
16.5
17.0

145
1,880
1,850
_
_
.
_

_
-
-

118
110

_
-
.

-
-
-

-
-
-

-------
                         Table A-3
Weekly Composite Metal Results for Common Primary Effluent
            Baltimore Phosphate Removal Study
Date

7/14-17/69
7/22-25/69
7/29-31/69
8/4-8/69
8/11-15/69
8/18-22/69
8/25-29/69
9/2-5/69
9/8-12/69
9/15-19/69
9/20-26/69
9/29-10/3/69
10/7-10/69
1 0/1*4- 17/69
10/20-23/69
10/28-31/69
11/3-7/69
11/10-14/69
11/17-20/69
1 i/2lt-28/69
12/1-U/69
12/6-11/69
12/11-16/69
12/18-23/69
Average
Range
Calcium
mg/L
28.9
2lt-.0
30.0
30.0
24.5
23.0
25-5
22.5
21.8
24.0
23.0
27.0
25.5
26.0
-
-
-
-
-
26.0
26.5
25.5
25.0
22.0
25.3
21.8-30.0
Magnes ium
mg/L
11.3
11.0
11.5
11.0
12.5
9.0
8.8
9.2
8.8
9.6
10.7
10.8
12.5
13.0
10.0
11.0
11.8
13.6
10.4
13.0
14.2
11.8
13.7
10.6
11.2
8.8-14.2
1 rqn
mg/L
3.1
2.3
2.3
2.5
2.7
1.5
3.0
4.5
3-8
3.5
6.2
4.4
-
6.0
3.5
2.6
1.9
1.3
3.3
2.5
3.7
2.3
4.8
2.6
3.2
1.3-6.0
Alumi num
mg/L
-
2.0
3.5
3.5
2.5
2.5
1.6
2.1
2.9
2.6
1.6
3.8
1.6
1.9
1.2
0.8
_
-
_
1.0
1.5
1.5
3.0
0.9
2.1
0.8-3.8
Copper
mg/L
0.3
0.4
0.3
0.3
0.3
0.2
0.7
0.4
0.4
0.3
0.4
0.6
0.9
0.4
0.4
0.2
_
_
_
_
_
_
_
-
0.4
0.2-0.9
Zl nc
mg/L
0.7
1.5
0.6
0.7
0.8
0.7
0.8
0.9
1.2
0.9
0.9
1.6
0.9
1.9
0.9
1.2
.
H
..
n
M
—
„.
-
1.0
0.6-1
                            110

-------
Table A-3
(continued)
Weekly Composite Metal Results for Control Final

Date

7/1^-17/69
7/22-25/69
7/28-31/69
8A-8/69
8/11-15/69
8/18-22/69
8/25-29/69
9/2-5/69
9/8-12/69
9/15-19/69
9/22-26/69
9/29-10/3/69
10/7-10/69
ioM- 17/69
10/20-23/69
10/28-31/69
i 1/3-7/69
11/10-1V69
11/17-20/69
1 1/2^-28/69
12/1-V69
12/6-11/69
12/11-16/69
12/18-23/69
Average
Range
Bal
Calcium
mg/L
23.3
28.0
22.0
28.0
-
22.0
22.0
25.0
22.8
21.5
26.0
22.5
22.5
23-5
-
18.6
-
-
-
23.5
26.8



23.6
18.6-28.
timore Phosphate
Magnesium
mg/L
Q.k
10.7
10.0
10.0
7.2
7.2
7.6
7.7
-
Q.k
8.0
8.3

7.5
8.0
8.8
7.6
7.7
6.1
6.8
7.2
Control system


8.1
0 6.1-10.7
Remova 1
1 rqn
mg/L
0.5
0.9
0.9
0.8
0.8
0.6
1.3
0.7
1.7
1.7
<0.1

-------
Weekly Composite Metal
Date

7/114-17/69
7/22-25/69
7/28-31/69
8/U-8/69
8/11-15/69
8/18-22/69
8/25-29/69
9/2-5/69
9/8-12/69
9/15-19/69
9/22-26/69
9/29-10/3/69
10/7-10/69
10/lU- 17/69
10/20-23/69
10/28-31/69
11/3-7/69
11/10-1V69
11/17-20/69
11/214-28/69
12/1-4/69
12/6-11/69
12/11-16/69
12/18-23/69
Average
Range 19
Bait
Calcium
mg/L
22.3
25.0
25.0
25.0
2k. 0
22.0
21.5
-
19.2
23.2
23.5
23.5
25.5
22.0
-
19.0
-
-
-
23.0
2k.8
25.0
2k. 0
22.5
23.2
.0-25.5
Table
(cont i
Results for
A- 3
nued)
Test Final
imore Phosphate Removal
Magnesium 1 ron
mg/L
9.1
10.7
10.7
8.2
7.7
6.5
7.0
-
7.8
7.8
8.3
8.0
-
8.0
9.8
12. U
8.3
9.0
7.7
7.9
7.k
9.2
12.2
12.2
8.9
6. 5-12. k
mg/L
0.8
1.9
0.6
0.7
0.6
0.5
1.0
l.o
0.8
0.8
< 0.1
< 0.1
< o.i
<0.1
1.1
2.1
1.3
0.6
0.9
0.1
0.1
< 0.1
0.1
0.1
0.7
.1-2.1
Effluent (System No.
Study
Aluminum Copper
mg/L mg/L
<0.5 <0.1
1.0 0.2
1.5 <0.1
3-5 o.i
1.5 <0.1
2.5 
-------
Weekly Composite
Date

7/7-11/69
7/14-17/69
7/22-25/69
7/29-31/69
8A-8/69
8/11-15/69
8/18-22/69
8/25-29/69
9/2-5/69
9/8-12/69
9/15-19/69
9/20-26/69
9/29-10/3/69
10/7-10/69
10/14-17/69
10/20-23/69
10/28-31/69
1 1/3-7/69
H/10-1V69
11/17-20/69
1 1/24-28/69
12/1-V69
12/6-11/69
12/11-16/69
12/18-23/69
Average
Range 3
Table A-3
(cont inued)
Metal Results for Control Aeration Tank Outlet (System No. 1)
Baltimore Phosphate Removal Study
Calcium
mg/L
34.8
48.6
90.0
83.0
86.0
49.5
47.5
-
-
49.0
38.5
-
31.0
35.0
38.0
-
-
-
-
-
65.0
-



53.3
1.0-90.0
Magnesi
mg/L
25.0
28.6
27.5
30.0
32.7
28.0
28.0
31.0
40.0
23.7
26.3
28.0
28.0
25.5
31.0
31.0
35.6
31.5
33.0
31.3
34.6
34.6

(Control

30.2
23.7-40.
urn 1 ron
mg/L
27.0
27.7
23.0
16.8
20.0
10.3
-
24.0
36.0
-
-
30.0
35.2
21.2
23.6
25.0
24.4
14.0
25.0
27.4
30.5
26.5

System Not

24.6
o 10.3-36
Aluminum
mg/L
14.3
17.7
8.5
8.5
14.5
8.5
5.5
22.0
33.0
-
-
26.5
-
19.0
17.5
16.0
16.0
11.0
11.5
8.5
21.8
13.3

Operating)

15.4
.0 5.5-33.0
Copper
mg/L
3.2
4.4
1.0
3.0
4.0
3.2
3.8
4.6
5.2
4.6
3.2
3.4
5.5
5.6
5.2
1.3
1.2
-
-
-
-
-



3.7
1.0-5.6
Zinc
mg/L
5.5
8.4
9.5
7.6
_
7.2
8.1
6.1
9.0
10.0
6.7
6.3
11.0
7.3
10.0
6.6
5.5
-
-
-
-
-



7.8
5.5-11.0
113

-------
Weekly Composite
Date

7/7-11/69
7/1^-17/69
7/22-25/69
7/29-31/69
8/4-8/69
8/11-15/69
8/18-22/69
8/25-29/69
9/2-5/69
9/8-12/69
9/15-19/69
9/20-26/69
9/29-10/3/69
10/7-10/69
10/1 it- 17/69
10/20-23/69
10/28-31/69
1 1/2-7/69
11/10-14/69
11/17-20/69
1 1/24-28/69
12/1-4/69
12/6-11/69
12/11-16/69
12 / 16- 23/69
Average
Range
Table A- 3
(cont inued)
Metal Results for Test Aeration
Balti
Calcium
mg/L
If 1.6
51.7
49.5
-
64.0
46.0
36.5
47.5
30.0
4o.o
44.0
27.5
-
32.8
3^.5
-
-
-
-
-
-
-
74.0
-
-
44.0
27.5-74.0
more Phosphate Removal
Magnes ium
mg/L
25.5
18.0
19.7
32.0
27.5
25.0
18.5
34.0
46.5
25.7
24.5
21.3
39.5
29.5
28.0
25.2
-
32.2
32.8
25.5
24.0
31.6
38.8
48.0
29.0
28.2
18.0-48.0
1 ron
mg/L
30.0
11.5
11.5
27.0
25.2
-
-
-
36.0
8.8
-
31.5
15.0
23.6
56.0
29.2
23.8
15.2
24.5
26.8
16.0
24.0
33.0
35.0
27.2
25.3
8.8-56.0
Tank Outlet
Study
Alumi num
mg/L
26.8
10.8
8.0
14.0
13.0
^.5
5.7
9.1
44.0
5.7
12.3
31.5
37.5
21.0
19.0
16.0
9.1*
ll.o
12.5
9.0
12.2
13.5
18.0
16.4
13.0
15.7
4.5-44.0
(System
Copper
mg/L
4.2
3.2
3.1
4.2
2.3
3.1
-
6.6
7.2
3.5
2.2
4.0
5.2
5.^
b.9
1.8
1.9
-
-
-
-
-
-
-
-
3.9
1.8-7.2
No. 2)
Zi nc
mg/L
7.5
7.0
13.7
9.5
-
6.5
5.7
9.2
11.5
6.7
6.2
7.0
9.5
7.6
6.5
7.7
5.5
-
-
-
-
-
-
-
-
8.0
5.5-11
114

-------
Weekly Compos i
Date

7/17-11/69
7/14-17/69
7/22-25/69
7/29-31/69
S/Ii-8/69
8/11-15/69
8/18-22/69
8/25-29/69
9/2-5/69
9/8-12/69
9/15-19/69
9/20-26/69
9/29-10/3/69
10/7-10/69
10/14-17/69
10/20-23/69
10/28-31/69
11/3-7/69
11/10-7/69
11/17-20/69
11/24-28/69
12/1-4/69
12/6-11/69
12/11-16/69
12/18-23/69
Average
Range
Table A-3
(continued)
te Metal Results for Control Return Sludqe (System No
Bal
Calcium
mg/L
121
131
168
120
165
92
-
80
-
-
138
101
73
-
79
-
-
-
-
-
145
118



118
73-168
• 1)
timore Phosphate Removal Study
Magnes ium
mg/L
92
60
142
-
80
42
121
97
67
131
89
104
115
-
106
83
192
140
110
120
110
92

(CONTROL

105
42- 192
1 ron
mg/L
100
87
-
_
-
-
164
50
66
218
-
124
160
^3
124
110
122
132
98
122
&9
67

SYSTEM

110
43-218
Aluminum
mg/L
90
75
-
_
_
-
-
61
66
115
-
123
133
40
81
80
88
115
38
65
39
32

NOT OPERATING)

78
32-133
Coppe r
mg/L
23
18
14
12
15
18
-
23
11
20
14
19
24
-
24
7
12
-
-
-
-
-



17
7-24
Zinc
mg/L
37
35
40
23
28
3^
43
30
19
48
38
33
42
-
41
29
31
-
-
-
-
-



3^
19-48
115

-------
Weekly Compos
Date

T/T- 1 1 /69
T/! 4- 17/69
7/22-25/69
7/29-31/69
8 A- 8/69
8/11-15/69
8/18-22/69
8/25-29/69
9/8-12/69
9/15-19/69
9/20-26/69
9/29-10/3/69
10/7-10/69
10/1 It- 17/69
10/20-23/69
10/28-31/69
11/3-7/69
11/10-7/69
11/17-20/69
11/24-28/69
12/1-4/69
12/6-11/69
12/11-16/69
12/18-23/69
Average
Range
ite Metal
Table A-3
(cont inued)
Results for Test Return Sludge (System No.
Baltimore Phosphate Removal
Calcium
mg/L
148
102
165
160
198
98
7^
107
101
io4
59
62
-
77
-
-
-
-
-
-
135
145
-
-
113
59-198
Magnes ium
mg/L
63
55
-
69
95
46
37
100
88
100
145
91
79
147
83
94
102
86
89
69
93
129
122
70
90
37-147
1 ron
mg/L
51
83
-
80
-
-
-
-
-
133
103
121
109
190
122
119
103
89
122
53
70
92
89
60
99
53-190
Study
Al uminum
mg/L
50
61
-
-
-
30
20
47
-
61
110
105
78
110
76
96
50
33
70
27
26
33
41
34
59
20-1 10
Copper
mg/L
24
19
-
15
16
-

25
12
14
-
17
14
27
8
11
-
-
-
_
-
-
-
-
17
8-27
2)
Z inc
mg/L
4o
37
38
38
4o
19
20
-
36
30
24
33
25
46
31
26
-
-
-
-
-
-
-
-
32
19-40
116

-------
                               Table A-4
                    Baltimore Phosphate  Removal Study
                         Summary of  Plant  Samples

Date
Submitted
8/1/69
8/5/69
8/6/69
8/7/69
8/12/69
8/13/69
8/14/69
8/27/69
8/28/69
8/29/69
9/10/69
9/11/69
9/12/69
9/17/69
9/18/69
10/1/69
10/2/69
10/3/69
10/8/69
10/9/69
10/10/69
10/23/69
10/24/69
H/7/69
11/12/69
11/13/69
11/14/69
11/19/69
11/20/69
11/21/69
12/3/69
12/4/69
12/5/69
12/10/69
12/11/69
12/12/69
12/17/69
12/18/69
12/19/69


1 2
Raw Degritted
13.0

4.7
6.5
9.2
8.8
9-2
9.0
8.8
7.7
8.7
9.2
7.0
8.6
13-5
9.5
10.5
5.7
8.0
_
4.7
8.7
7.0
7.6
6.2
-
7.4
8.1
8.2
8.6
9.4
9.6
6.3

3.2
7.6
7.6
6.2
5.5
12.5

6.5
7.9
9.7
9.5
9-0
8.5
8.2
7.2
9-5
10.0
7.8
9.2
7.8
10.3
10.3
7.2
8.0
-
6.5
—
7.5
7.6
6.5
11.1
8.1
7.5
8.5
9-3
9.6
10.5
6.0
9.3
5.4
7.6
9-5
6.4
6.1
Ortho Phosphate - mg P/|_
l°Settled
15.3

8.2
9.3
ll.l
10.2
8.5
10.4
9.7
9.0
9.9
12.5
11.5
11.4
10.0
12.0
11.4
9.9
9-7
9.3
10.9
_
9-6
9-2
9.2
12.1
10.7
10.2
-
9.0
12.3
ll.l
9.7
12.2
9.7
6.3
9.5
9.5
6.9
k
2°ASEff.
11.8
—
1.0
1.7
2.4
4.8
2.5
0.5
0.6
0.3
2.7
1.5
0.8
0.5
_
2.5
0.3
2.5
3-6
0.5
0.5
11.7
5.1
0.4
2.2
0.5
1.9
-
-
-
4.1
1.0
0.6
1.9
1.2
0.9
3-2
0.2
2.4
5
TF Outlet
13.7

7.8
8.0
8.8
9.5
10.4
11.0
5.3
10.0
9.o
9.6
12.5
7.7
6.3
13.2
12.2
_
10.5
10.0
9.6
11.5
9.3
9.2
10.1
13.1
9.6
12.9
10.3
-
11.9
11.7
11.2
12.2
11.3
7.0
8.8
7.9
8.1

6
2°TF Eff.
15.0

8.9
7.3
8.0
9.0
10.3
10.5
6.2
7.7
12.7
-
12.0
7.3
8.8
9.5
12.8
9.8
11.6
8.0
10.0
10.8
10.2
9-6
8.0
i4.o
9-5
i4.o
10.1
-
-
10.6
10.2
"•
10.9
7.o
11.8
8.1
9.5
3-6
TF
Removal
Percent
0
H
0
22
28
12
0
0
36
14
0
-
0
36
12
21
0
2
0
14
8
-
0
0
13
0
11
0
-
-
1
14
0
-
0
0
0
15
0
3-4
AS
Removal
Percent
23

88
82
78
53
71
95
94
97
73
88
93
96
-
79
97
75
63
95
95
-
47
96
76
96
82
-

-
67
91
94
85
88
86
66
98
70
Average
8.0
                     8.4
10.2
2.3
10. 1
10. 0
81
                              117

-------
                                           Table A-4
                                           (continued)
                                Baltimore Phosphate Removal  Study
                                     Summary of Plant Samples
                                     Total  Phosphate - mg P/L


Date
Submitted
7/31/69
8/1/69
8/5/69
8/6/69
8/7/69
8/12/69
8/13/69
8/14/69
8/20/69
8/21/69
8/22/69
9/3/69
9 A/69
9/5/69
9/10/69
9/11/69
9/12/69
9/24/69
9/25/69
9/26/69
10/3/69
10/15/69
10/16/69
10/17/69
10/23/69
10/2^/69
10/29/69
10/30/69
10/31/69
11/5/69
11/6/69
11/7/69
11/12/69
11/13/69
11/14/69
11/19/69
11/20/69
11/21/69
11/26/69
11/28/69
12/3/69
12/4/69
12/5/69
12/10/69
12/11/69
12/12/69


1
Raw
20.0
16.0
10.0
11.0
12.0
-
10.0
15.0
20.0
8.0
13-5
6.5
7.5
6.0
13.0
10.8
10.0
9.4
11.4
9.4

16.6
11.6
9.1
9.7
8.5
9.0
7.5
10.0
8.6
6.6
8.8
12.6
10.8
_
9.8
10.0
11.0
13.0
11.8
10.8
10.5
9.0
10.0
4.5
8.4


2
Degritted
16.0
16.0
10.5
10.0
13.0
10.0
i4.o
18.0
16.0
9.5
15.5
7.0
12.0
5-5
16.4
11.5

12.2
13.4
9.8

18.4
11.4
8.8
9.6
9.4
7.8
9.0
10.8
7.4
7.0
8.4
11.0
11.6
_
13.2
10.4
_
13.4

11.4
11.6
9.0
11.0
8.4
8.8


_ 3
1 Settled
15.0
16.0
11.0
10.0
15.0
12.0
15.0

13.5
10.5
13.5
9.5
10.0
9.4
15.5
15.5

13.0
12.2
12.2
9.9
13.0
13.2
13.2
11.5
10.7
11.4
10.2
11.1
9.8
9.6
9.6
13.2
12.2
_
13.6

_
14.6
15.4
13.6
11.8
11.0
12.4
12.6
7.8


4
2°AS Eff.
8.0
14.0
2.5
4.5
5.0
4.0
3.0
7.0
3.5
2.0
1.0
1.5
2.0
1.5
3.8
2.0
_
1.0
1.0
1.0
2.8
2.7

1.0
12.4
5.5
3.9
4.8
4.7
0.8
0.7
0.6
2.4
0.8
2.6
3.2

_
3.2
2.0
4.8
1.8
1.2
2.8
2.0
1.4


5
TF Outlet
15.0
16.0
9-5
9.0
15.0
11.0
12.0
15.0
15.0
13.0
8.5
10.5
8.5
7.5
12.8
11.5
13.6
13.6
8.5
11.0
_
12.5
10.2
12.4
11.7
9.6
11.2
9.0
10.2
10.1
11.4
_
10.6
13.8
10.5
14.6
14.4
11.0
12.0
18.8
12.4
11.8
11.5
13.0
11.2
7.0


6
2° TF Eff.
14.0
16.0
8.5
9.0
16.0
10.0
12.0
18.0
14.0
13.0
8.0
9.5
9.0
7.5
15.0
13.0
12.8
12.6
9.4
10.0
9.8
13.2
11.6
11.6
_
11.2
11.0
7.2
8.7

9.1
9.7
10.7
14.8
_
14.0
10.6
10.6
12.8
11.8
12.2
10.8
11.0
11.6
fm
_
3-6
TF
Remova 1
Percent
11
0
23
10
0
17
20
0
0
0
14
0
10
20
3
16
_
3
23
18
1
1
12
12
_
0
0
29
22
_
5
o
11
0

0


12
23
10
8
0
6
—
_
3-4
AS
Removal
Percent
47
13
77
55
67
67
80
59
'74
81
93
84
80
84
75
87

92
92
92
72
79

92
0
45
66
53
58
92
93
94
82
93
70
76


78
87
65
85
89
77
84
82
Average   10.6
11.3
12.2
3.2
11.7
H.5
74
                                         118

-------
                                           Table A-4
                                           (continued)

                                Baltimore Phosphate Removal  Study
                                     Summary of Plant Samples
                                     Ammonia Nitrogen -  mg N/L


Date
Submi tted
T/31/69
8/1/69
8/5/69
8/6/69
8/2T/69
8/28/60
8/29/69
9/10/69
9/11/69
9/12/69
9/17/69
9/18/69
9/19/69
10/1/69
10/2/69
10/3/69
10/23/69
10/24/69
10/29/69
10/30/69
10/31/69
11/5/69
11/6/69
11/7/69
11/12/69
11/13/69
11/14/69
11/19/69
11/20/69
11/21/69
12/10/69
12/11/69
12/12/69
12/17/69
12/18/69
12/19/69


1
Raw
11.0
17.2
15.3
11.7
21.2
12.2
13-7
14.5
14.2
14.2
16 A
17.8
20.8
16.7
17.3
19.5
23.5
22.0
19.3
20.5
24.7
16.3
17.7
-
19.5
23.9
28.0
-
26.1
21.4
22.3
16.6
19.6
27.3
20.1
28.8


2
Degri tted
15.?
20.5
17.0
17.5
17-5
13.0
11*. 8
18.3
15.0
13.0
16.6
20.5
24.5
19.2
19. ?
22.0
28.4
28.0
20.0
23.0
25. 4
16.8
18.5
-
20.8
24.2
-
20.8
22.9
22.5
20.7
19.8
19.4
29.1
19.3
30.3


3
1 Settled
13.4
19.0
18.4
20.0
22.0
_
16.9
18.8
15.9
18.7
27.0
26.9
29.5
21.5
18.8
26.0
24.6
-
22.1
23.5
28.0
20.7
18.7
-
26.0
-
-
26.6
-
-
26.7
25.7
23.1
27.2
24.8
25.4


4
2° ASEff .
11.0
11.7
12.5
13.0
11-9
10.1
10.7
10.9
6.7
3.0
10.0
8.2
8.8
i4.o
12.5
14.2
15.2
-
-
-
17.5
16.1
13.8
-
14.9
-
-
18.3
-
-
15.2
13.6
12.1
18.6
18.6
16.7


5
TF Outlet
14.7
26.0
22.5
21.0
15.5
16.4
15.8
17.5
17.7
19.4
22.0
22.3
36.5
18.9
18.0
20.7
-
-
18.7
19.1
22.4
19.8
16.9
17.7
-
-
-
23.8
22.1
19.0
23.5
17.0
22.4
20.4
22.4


6
2°TF Eff.
15.0
18.5
20.0
22.5
16.0
18.1
.
16.3
17.5
18.5
19.4
17.8
18.5
20.0
20.0
19.0
-
-
21.0
-
-
18.5
17.2
19.1
-
-
-
-
19.8
17.4
-
18.3
16.6
-
20.3
20.1
3-6
TF
Remova 1
Percent
0
3
o
o
27

_
13
0
1
28
34
37
7
0
27
_
-
5
-
-
10
8
-
-
-
-
-
-
-
-
29
28
-
18
26
3-^
AS
Remova I
Percent
18
38
32
35
46
_
37
42
58
84
63
70
70
35
34
45
38
_
-
_
38
22
26
-
43
-
-
31
-
-
^3
47
48
32
25
34
Average
           18.7
20.4
22.6
12.9
20.3
18.6
14
42
                                         119

-------
                                            Table A-4
                                           (continued)

                                Baltimore Phosphate Removal Study
                                     Summary of Plant Samples
                            Total Kjeldahl Nitrogen - rug N/L


Date
Submitted
7/31/69
8/1/69
8/5/69
8/6/69
8/7/69
8/12/69
8/13/69
8/1^/69
8/21/69
8/22/69
9/3/69
9 A/69
9/5/69
9/10/69
9/11/69
9/12/69
9/24/69
9/25/69
9/26/69
10/2/69
10/3/69
10/8/69
10/9/69
10/10/69
10/23/69
10/24/69
10/29/69
10/30/69
10/31/69
11/6/69
H/7/69
11/12/69
11/13/69
11/14/69
11/19/69
11/20/69
11/21/69
11/26/69
11/28/69
12/3/69
12A/69
12/5/69
12/10/69
12/11/69
12/12/69


1
Raw
36.0
35.0
26.0
24.0
24.0
18.0
20.0
22.5
29.0
30.0
17.8
21,0
18,5
29.5
29.5
30.0
27.8
31.0
26.2
_
_
20.0
_
12.2
_
n
26.5
28.8
27.3
24.0
27.0
33.0

-
24.6
27.8
26.4
31.5
33.0
30.0
22.4
31.0
23-5
20.6
22.6


2
Deqri tted
4o.O
42.0
29.0
23.0
28.0
19.0
24.0
27.0
31.0
34.0
30.0
27.0
17.0
35.0
31.0

33-0
40.0
27.0
_
_
18.2
_
13.8

_
27.9
38.1
27.9
23.8
27.2
30.5

17.0
36.0
32.0
_
32.0
—
32.0
27.8
31-0
24.0
24.0
23-5


3
1 Settled
32.0
38.0
30.0
23.5
30.0
19.5
24.0
23.5
32.0
33.0
24.0
25.0
26.0
34.0
32.0
..
31.0
23.0
30.0
_
9.9
21.0
18.8
14.2
_
21.3
33.3
33.9

24.0
24.2
28.2
23.4
21.6
-
_
_
-
34.0
34.0
28.8
28.8
25.0
26.0
24.0


4
2°AS Eff.
20.0
18.0
13.0

17.0
13.5
14.0
16.5
24.0
19.0
4.0
6.8
6.4
13-5
9.8

14.0
12.0
i4.o
1.0
_
10.4
9.0
8.2
24.8
11.0
16.2
15.6
20.4
18.0
14.0
_
15.0
14.0
18.4
_
_
31.0
16.8
17.4
13.2
14.8
17.0
16.8
14.0


5
TF Outlet
32.0
38.0
28.0
21.0
25.0
19.5
20.0
22.0
32.0
26.0
23.0
21.0
21.0
28.0
28.5
29.0
27.6
22.2
25.0
_
_
14.2
9.2
15.8
23.5
19.2
_
21.6
_
_
_
18.6
20.8
20.2
28.2
26.4
20.4
22.0
35.0
19.4
20.8
23.8
23.5
23.5
18.0


6
2°TF Eff.
28.0
28.0
23.0
23.0
25.0
15.0
20.0
21.0
30.0
25.0
19.0
20.0
21.5
27.0
27.5
27.5
28.5
19.6
25.4
—
9.8
,16.6
13.4
15.6
20.8
22.5
21.0
21.6
20.7
18.8
_
19.4
22.6
17.8
23.4
_
20.0
17.4
21.6
19.6
20.2
23.2
21.4
21.8
17.0
3-6
TF
Removal
Percent
13
26
23
2
17
23
17
11
6
24
21
20
17
21
14
_
8
15
15

1
21
29

_
_
37
36

22

31
3
18
38


49
36
42
30
19
14
16
42
3-4
AS
Remove 1
Percent
38
53
57

43
31
<
30
25
48
83
73
75
60
69

55
48
53

_
50
52
42

54
51
54

25
42

36
35
52


9
51
49
54
49
32
35
42
Average   26
28. 4
26.6
14.7
22.9
21.I
21.6
                                         120

-------
   Date      1
Submitted   Raw
7/31/69
8/1/69
8/5/69
8/6/69
8/7/69
8/27/69
8/28/69
8/29/69
9/17/69
9/18/69
9/19/69
10/1/69
10/2/69
10/3/69
10/15/69
10/16/69
10/17/69
10/23/69
10/21+/69
10/29/69
10/30/69
10/31/69
11/5/69
11/6/69
11/7/69
11/12/69
11/13/69
11/1^/69
12/3/69
12/1+/69
12/5/69
12/17/69
12/18/69
12/19/69
255
370
11+5
135
135
175
175
170
135
130
ll+O
85
95
120
105
125
120
105
115
125
ll+O
180
75
85
150
85
105
ll+O
ll+O
125
135
120
115
160
280
365
150
160
145
160
150
205
135
165
ll+O
95
100
135
115
130
120
115
120
105
ll+O
190
75
85
150
90
130
ll+O
125
125
135
125
110
165
                                             Table  A-4
                                             (continued)

                                  Baltimore  Phosphate  Removal  Study
                                       Summary of Plant  Samples
                                       Total Carbon -  mg C/|_
Degritted   l°Settled
                       225
                       335
                       165
                       150
                       190
                       175
                       175
                       135
                       160
                       110
                       100
                       165
                       110
                       litO
                       155
                       115
                       125
                       125
                       ll+O
                       11+5
                        80
                        90
                       125
                       110
                       120
                       130
                       11*0
                       135
                       135
                       120
                       120
                       1JO
                                     Eff.
                                             125
Average
139
                                               75
                                               80
                                               70
                                               80
                                               75
                                               70
                                               60
                                               55
                                               60
                                               60
                                               60
                                               70
                                               60
                                               80
                                               60
                                               60
                                               75
                                               65
                                               70
                                               95
                                               55
                                               55
                                               55
                                               65
                                               60
                                               65
                                               70
                                               60
                                               70
                                               60
                                               60
                                               60

                                               70
TF Outlet

  180
  215
  100
  105
  105
  120
  100
  120
   95
   75
   75
   75
   80
  100
   90
   85
   95
   85
   80
   70
   75
   90
   60
   60
   60
   85
   75
   80
   90
   95
   95
   70

   85

   92


6
2°TF Eff.
170
215
110
110
100
125
95
115
85
75
80
70
95
95
80
_
95
80
80
75
70
90
60
50
65
65
85
80
90
85
85
70
65
75
3-6
TF
Removal
Percent
24
36
24
33
33
34
46
34
37
46
50
36
5
42
27
_
39
30
36
4o
50
38
25
44
48
41
29
38
36
37
37
42
46
42
3-4
AS
Removal
Percent
44
58
48
52
53
58
57
60
55
61
63
45
4o
58
45
43
6l
48
40
48
50
34
31
39
56
41
50
50
50
56
48
50
50
54
                                                      90
37
50
                                           121

-------
   Date      1
Submitted   Raw
7/31/69
8/1/69
8/5/69
8/6/69
8/7/69
8/27/69
8/28/69
8/29/69
9/10/69
9/11/69
9/12/69
9/17/69
9/18/69
9/19/69
10/1/69
10/2/69
10/3/69
10/8/69
10/9/69
10/10/69
10/15/69
10/16/69
10/17/69
10/23/69
10/24/69
11/5/69
11/6/69
11/7/69
11/12/69
11/13/69
11/14/69
H/19/69
11/20/69
11/21/69
12/3/69
12/4/69
12/5/69
12/10/69
12/11/69
12/12/69
12/17/69
12/18/69
12/19/69
550
520
230
260
310
195
190
200
220
245
230
_
370
390
170
200
220
130

115
115
150
130
250
260
100
85
240
95
150
225
100
105
165
205
160
195
210
50
100
235
235
360
580
490
250
290
350
205
210
225
230
240
230
300
370
395
175
210
240
130

215
125
150
130
250
240
75
95
235
95
170
260
95
100
205
150
175
185
90
65
100
260
215
400
                                             Table A-4
                                            (continued)

                                  Baltimore  Phosphate Removal Study
                                       Summary  of Plant  Samples
                                             COD mg/L
       Degritted   1 Settled
                                  520
                                 250
                                 290
                                 310
                                 215
                                 200
                                 200
                                 220
                                 245
                                 240
                                 300
                                 380
                                 390
                                 210
                                 205
                                 235
                                 150
                                 160
                                 24o
                                 125
                                 11*0
                                 220
                                 250
                                 240
                                   65
                                 105
                                 180
Average
211
219
                                 165
                                 205
                                 100
190
195
200
1JO
 75
 70
230
230
280

219
4
2°AS Eff.
180
170
70
90
130
50
65
75
60
65
60
105
75
90
65
70
75
45
35
40
20
85
20
55
60
45
40
40
50
45
65
45
_
_
^5
40
45
50
50
4o
80
55
50
64
122
5
TF Outlet
260
280
150
180
210
170
120
160
140
110
l4o
160
110
150
130
150
170
70
85
195
85
70
100
120
110
60
60
80
75
100
90
75
65
65
75
90
95
80
70
50
80
75
125
117



6
2°TF Eff.
250
220
150
i4o
180
155
125
155
145
150
i4o
ito
105
170
125
155
155
70
80
110
75
_
100
100
120
55
60
80
85
90
95
80
75
80
80
70
85
65
65
60
85
80
110
3-6
TF
Remova 1
Percent
52
55
ho
52
42
28
38
23
34
39
42
53
72
56
40
24
34
53
50
54
40
_
55
60
50
15
43
55
41
45
54
-
_
_
50
64
58
50
13
14
63
65
61
3-4
AS
Remova 1
Percent
65
65
72
69
58
77
68
63
73
73
75
65
80
77
69
66
68
70
78
83
84
40
91
78
75
31
62
78
65
73
69
55
_
_
76
79
78
92
33
43
65
76
83
112
46
                                                                                 69

-------
                                            Table A-4
                                           (continued)

                                 Baltimore  Phosphate  Removal Study
                                      Summary  of  Plant  Samples
                                 Combined Nitrate-Nitrite - mg N/L


Date
Submitted
7/31/69
8/27/69
8/28/69
8/29/69
9/17/69
9/18/69
9/19/69
10/1/69
10/2/69
10/3/69
10/8/69
10/^/69
10/10/69
10/15/69
10/16/69
10/17/69
10/29/69
10/30/69
10/31/69
11/19/69
11/20/69
11/21/69
12/3/69
12/4/69
12/5/69
12/17/69
12/18/69
12/19/69


1
Raw
0.10
0.10
0.05
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
-
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.25
0.18
0.15
0.10
0.10
0.10
0.10
0.10
0.25


2
Degr i tted
0.10
0.10
0.05
0.10
0.10
0.20
0.10
0.10
0.10
0.10
0.10
_
0.10
0.10
0.10
0.10
0.10
0.10
o.io
0.13
0.18
0.15
0.10
0.10
0.10
0.10
0.10
0.25


o 3
1 Settled
0.10
0.10
2.80
0.05
0.15
0.25
0.20
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
.10
.10
.10
_
-
-
0.20
0.20
0.10
0.10
0.10
-


4
2°AS Eff.
0.15

!so
2.90
2.20
3.00
3.10
1.80
2.30
3.10
~Z. }^Q
1.90
1.70
1.30
i.4o
1.20
0.8
0.8
0.7
2.2
-
-
0.10
0.10
0.15
0.25
0.25
0.50


5
TF Outlet
0.90
o.4o
2.80
2.10
0.20
.20
1.70
0.10
0.10
0.70
0.20
1.70
2.50
0.10
0.70
1.00
2.4
2.1
1.7
0.25
0.25
2.6
0.10
0.10
1.4
o.75
1.7
0.80


6
2°TF Eff.
1.10
0.30
3.00
2.95
0.10
0.95
1.70
1.10
0.60
2.70
0.80
2.40
2.10
0.10
_
1.10
2.9
3.0
1.4
2.4
4.0
3.6
0.10
0.10
2.9
1.8
1.7
1.4
3-6
TF
Increase
Times
11
4
0
59
0
4
9
11
6
27
8
24
21
0
-
11
29
30
14
_
-
-
0
0
1
2
2
-
3-4
AS
Increase
Times
1
14
0
58
15
12
16
18
23
31
34
19
17
13
14
12
8
8
7

-
-
0
0
29
18
17
-
Average
0.11
                     0.11
0.23
1.45
1.06
1.71
12
16
                                          125

-------
                                                                                                            Table A.;


                                                                                                 Baltimore  Phosphate Removal Study


                                                                                                   Average Test Period Results
                                                                                                                                 Test  Period
Common PE BOO,, mg/L
Connon PE SS, rag/L
Cannon PE CODA. mg/L
Cannon PE Tot. Carbon, mg/L
Common PE Tot. P, mg/L
Conraon PE Ortho P04, mg/L
Coranon PE KJeldahl N, mg/L
Common PE Ammonia N, mg/L
Common PE pH, units
Control PE Flow, mgd
Control Return Sludge, $ PE
Control Sludge Wilting, % PE
Control A.T. HLSS, mg/L
Control A.T. VSS/SS, *
Control R.S. SS, mg/L
Control Secondary Effluent SS, mg/L
Control BOD, Loading, Ib/day/lb SS
Control Air Supplied, scfm/gal. PE
Control Sludge Production, Ib Waltad/lb BOD5(R)
Control 800s Removed, %
Control Tot. Carbon Removed, %
Control CODA Removed, %
Control Tot. P Removed, 1
Control Ortho P04 Removed, t
Control P In Waste Sludge SS, t
Control Eit. P Removal In Waited Sludge, %
Con
Con
Tat
Ta
Te
Te

Tas  R.S. SS,'ng/Lr
Te
Te
T.
Te
Ti
Ti
Te
T*
Tei
Ti
Te
Ti
Te
T.
Ti
rol Tot.  Kjeldahl H Removed,
rol Ammonia N Removed, %
rol SE Nitrite + Nitrate. mg/L
rol SE pH, units
 PE Flow
 Return Sludge, % n
 Sludge Wasting, % PE
 A.T. HLSS, mg/L
 A.T. VSS/SS,
 Secondary Effluent SS, mg/L
 BODB Loading, Ib/day/lb SS
 Air Supplied, scfm/gal PE
 Sludge Production, Ib Wasted/lb BOD,(R)
 BOD, Removed, %
 Tot. Carbon Removed,  £
 CODA Removed, %
 Tot. P Removed,  *
 Ortho P04 Removed, %
 P In Waste Sludge SS, <(
 Est. P Removal In Wasted Sludge, f
 Tot. Kjeldahl N Removed, %
 Aenonla N Removal, *
 SE Nitrite » Nitrate, mg/L
 SE pH. units
1
208
125
175

10.1
a.ii
13.0
9.8
6.3
8.0
22
1.8
2,250
73
11,000
7
0.28
1.25
1.16
82
___
67
80
81
2.1*
1*6
26
it
0.2
6.7
8.7
21
1.6
2,210
73
8,300
10
0.32
1.21
0.77
83
_»
61*
80
81
2.3
32
31
15
0.1
6.8
2
270
151*
230
..-
12.2
9.8
27.0
11*. 1
6.2
8.8
21
1.1*
2,160
73

9
0.1*2
1.23
0.51
92

81
1*3
Ui
2.7
28
1*1
1*0

6.7
8.9
21
1.1
2.130
71*
8.190
11
0.1*3
0.95
0.38
89
...
76
16
31*
3.0
25
37
22
— .
6.8
3
188
no
31*0
270
12.6
8.8
28.1
15. B
6.5
8.9
23
1.2
2.200
75
10,330
21
0.26
1.19
0.76
87
U*
72
52
"*3
3-5
39
35
29
0.1
7.0
9.0
22
1.1
2.080
78
10,010
20
0.31
1.05
0.72
82
38
63
22
10
2.7
21*
31
23
0.1
7.0
1,
155
123
268
11.1
10.1.
7.8

17^2
6.5
8.0
26
1.9
S.CJtO
73
9,1*00
11
0.23
1.52
1.21.
93
55
69
75
78
i*.l*
76
56
26
0.2
7.0
7.0
28
5.1
1,1*90
7"*
6,800
12
0.28
1.58
1.1*6
93
52
66
&
5"*
U.2
85
3>*
23
0.1
7.1
5
11*8
163
235
135
8.1*
7.1
23.0
19.7
6.1*
7.7
25
2.0
2,21*0
68
7.800
7
0.20
2.10
1.1O
90
69
79
85
96
5.0
93
59
51*
2.8
6.9
7.0
1*1*
1.2
3.060
67
9.500
11
0.13
2.1*5
0.89
87
65
78
85
95
l*.l*
60
51*
1*9
2.1*
6.9
6
179
173
255
113
15.2
8.0
23.9
17.7
6.5
9.1*
19
1.8
2,280
69
10.200
6
0.28
1.5^
1.28
80
1*9
71*
78
87
5.7
5>*
1*0
1*8
1.6
6.9
1*.7


2,230
68
8.500
5
0.11*
3.1.2
2.10
85
62
78
86
92
It. It
82
67
72
3.0
6.8
7
220
176
500
11.1
n.5
9.3
27.6
18.5
6.5
7.8
36
2.5
2,11*0
71
9,150
u
0.31
1.68
1.19
89
65
81
81.
90
lt.6
9?
1*9
50
1.5
7.0
8.5

u.o
1.950
73
6,600
9
0.37
1.70
1.30
92
55
80
86
91
l*.5
101
55
1*7
1.8
7.0
8
152
171
215
159
11.8
9.5
28. U
23.9
6.1.
10.lt
19
1.7
2,020
72
9,700
18
0.26
1.28
1.50
8J
65
71*
73
72
i*.l
57
39
1*1*
0.9
7.1
5.3
38
2.9
1,880
71
6,600
7
O.ll*
2.68
1.60
90
62
71.
89
92
I..9
79
1*0
Wt
1.3
7.0
9
178
151.

161
10.1
9.9
35.1.
5>t.l
6.1
9.1
22
2.5
2,190
72
8,200
111
0.28
1.27
1.19
97
63

91
96
5.1
105

55
0.2
6.9
9.5
16
1.7
2,050
73
9,000
111
0.32
1.83
0.89
96
63

86
90
>*.9
71*
-..
3"*
0.2
7.0
10
118
163
280
112
12.0
10.8
57.1
29.2
6.5
9.1
22
2.1*
1,850
76
7,200
16
0.25
1.32
1.63
90
1*8
82
1.7
51
5.7
jit
59

0.6
7.2
8.8
23
2.0
1,850
77
7,500
11*
0.22
1.1*2
1.55
82
1.6
76
18
51
5.1*
"*3
52
57
0.2
7.5
U
187
11*1*
21*5
173
13.5
11.5
26.5
*.}
6.2
9.6
21
2.2
1.970
77
8,i«X>
11
0.55
1.38
1.03
96
60
78
92
97
1..9
68
28
29
0.3
7.0
9.7
21
2.0
1,920
76
6,900
21
0.36
1.27
0.82
90
57
69
39
37
2.6
27
29
28
0.3
6.9
12
161
11.2
265
167
10.9
10.5

55.3
6.1.
10.7
19
1.8
1,91*0
71*
8,900
11
O.JIt
1.16
1.05
95
59
80
91*
95
5.8

...
1.9
0.1
7.1
5.1.

2.1.
1.990
72
7,300
15
0.17
2.65
1.12
96
60
80
91.
97
5.7
92

"36
0.3
7.3
13
190
lt.3
500
192
11.7
10.6
30.2
28.2
6.5
8.5
25
2.6
1,960
86
8,1*00
11
0.32
1.68
1.22
91*
62
82
90
95
5.5
102
36
38
0.1
7.1
9.0
22
2.1
1.900
75
8,000
10
0.35
1.29
0.91*

59
80
55
57
>*.9
77
33
35
0.1
7.0
15
173
133
305
172
10.8
9.7
37.9
32.8
6.5
9.1
22
2.2
1,990

...
U
0.52
1.27

91*
58
81.
BU
87
	

1.9
1*5
1.2
7.0
9.3
22
1.6
1,91*0
...
...
10
0.32
i.to
...
95
58
81*
85
88

...
1.8
1*1*
0.1*
7.1
16
178
102
282
156
10.6
9.0
31.9
29.5
6.1*
...
...
...
...

...
...
...
...
...
...
...
...

...
...

...
...
...
...
19.3
23
1.6
2,160
77
10,900
10
0.61 '
1.15
1.09
90
57
78
88
90
5-5
91
37
36
0.7
6.9
17
ito
101*
270
157
10.8
8.8
28.5
26.5
6.0
.«
...
...
...
«...
»
«
„
..
..
„
—
—
__
..
..

-- —
• -._
....
...
16.9
21*
1.7
2,120
73
9,700
18
0.51.

1 28
92
63
80
78
83
5-8
79
35
36
0.1
6.7
19
200
88
280
139
11.7
8.6
28.lt
27.9
6.2
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...
...

...
...
...
...
8.0
52
3.5
1,620
76
It, 200
7
0.38
1.51
0.78
96
58
79
32
30
I..3
5".
30
W.
0.1
6.9
Average
178
139
2»
159
11.3
9.2
28.2
23.8
6.3
8.9
22.8
2.0
2,086
73
9,063
11
0.29
1.1.2
l.llt
90
58
n
75
82
k.3
70

SB
0.75
7.0
9.1
28
2.2
2,033

8,000
12
0.32
1.69
1.10
90
57
75
63
65

'68
39
37
0.7
7.0

-------
                       Table A-6
                  PROFILE ANALYTICAL RESULTS
            _L_LJ_JLi_L-L_L
             PE  AT-1  AT-2 AT-3 AT-4  AT-5  AT-6 AT-7

1.  Normal  Control System 2/28/70 - 10:00 p.m., MLSS = i860, P/SS
= 4.6
D.O. mg/L
pH
Sol. COD mg/L
Ortho P04 mg/L
Sol. Tot. P mg/L
Tot.P mg/L
Sol. Tot. KN mg/L
Tot.KN mg/L
Sol.Mg mg/L
Tot.Mg mg/L
Sol.Ca mg/L
Tot.Ca mg/L
Sol.Fe mg/L
Tot.Fe mg/L
2. Normal Control
D.O. mg/L
Sol. COD mg/L
Ortho P04 mg/L
Sol. Tot.P mg/L
Sol. Tot.KN mg/L
Sol.Mg mg/L
Sol.Ca mg/L
Sol . Fe mg/L
3. Contact Stabil
D.O. mg/L
PH
Ortho P04 mg/L
Sol. Tot.P mg/L
Tot.P mg/L
Sol. Tot.KN mg/L
Tot.KN mg/L
SS mg/L
VSS mg/L
Sol. COD mg/L
Sol.MG mg/L
Sol.Ca mg/L
P/SS, Percent

0.0
6.2
435
8.6
16.6
20.1
27.1
32.0
9.8
_
30.0
_
1.52


6~5
205
16.2
24.0
99
25.8
138
14.6
21.2
30.6
57.0
0.58
24.0

6~5
120
16.1
21.1
102
23.6
150
12.8
26.8
29.0
60.0
_
32.4
System 2/13/70 -
0.0
308
4.9
7.0
22.0
11.7
31.4
0.26
izat
0.0
6.7
8.6
9.6
11.0
24.0
25.0
90
70
220
9.4
22.0
-


140
7.2
8.4
17.2
13.2
32.0
<.l

80
6.0
6.6
15.1
11.2
31.4
<.l

6~5
100
14.1
17.3
97
21.8
153
14.8
28.0
27.0
57.0
_
32.0
10:30

60
4.3
4.5
13.0
10.8
31.0
^.1

6~6
100
10.1
11.4
94
21.0
148
11.6
28.0
26.6
80.0
_
30.0
a.m.

65
3.3
3.5
12.6
9.9
31.0
<.l
Ion Test System 12/22/69
1.6
6.9
_
10.2
206
22.8
248
42:80
3095
_
9.6
22.5
4.6

2.5
6.8
_
9.6
194
23.0
230
4050
2925
_
10.4
22.5
4.5

3.0
6.9
_
9.2
160
22.6
202
3290
246o
-
9.2
22.5
4.6
125
0.7
6.9
_
9.8
86
21.8
118
1700
1335
-
10.4
21.5
4.5


6.6
87
6.6
7.6
90
20.7
144
12.4
25.6
26.6
74.0
_
29.6
, MLSS

55
2.5
2.5
12.0
9.6
31.4
<.l

6.7
85
3.6
3.8
88
19.8
140
10.4
25.2
28.0
50.0
_
27.6
= 2110

50
1.7
1.8
11.5
9.4
31.4
<.\
5.6
6.7
80
2.2
2.6
87
19.0
142
10.8
28.8
26.6
77.0
0.45
29.6

5.9
55
1.2
1.2
11.2
9.2
31.4
<.l
- 10:00 a.m.
5.0
6.9
_
9.0
91
21.2
125
1780
1430
-
9.6
21.5
4.6

7.3
7.0
_
9.6
96
21.5
128
1765
1325
-
11.7
22.5
4.9

8.0
7.0
_
8.8
94
20.8
127
1770
1330
-
9.6
22.5
4.8

                                                6.5
                                                135
                                               10.9
                                               12.3
                                                34o
                                               20.6
                                                505
                                               13.4
                                               75.2
                                               29.0
                                                110

                                                121
                                                 85
                                                7.9
                                                8.6
                                               13.5
                                               10.7
                                               31.0
                                                0.0
                                                6.8

                                               24.0
                                                208
                                               23.4
                                                256
                                               4180
                                               3270

                                               12.2
                                               25.5
                                                4.4
          SE
         6.8
          85
         0.5
         0.8
         l.o
         16.9
         17.0
         9.2

         30.0
          65
          1.9
          2.1
         12.2
          9.5
         31.0
          .1
          4.0
          7.1
          7.2
          8.8

         21.2
          55
          8.3
         22.0

-------
                                   Table A-6
                                  (continued)


                           PROFILE ANALYTICAL  RESULTS
                   PE   AT-1  AT-2  AT-3  "AT^T   AT-5  "AT3  AT-7      RS        SE

4.  Step Aeration Test System 12/16/69 -  10:'00  a.m.

                                                                                 2.0
                                                                                 6.8
                                                                                  55
                                                                                  30
                                                                                 4.4
                                                                                 6.8
                                                                                18.6
                                                                                21.2

                                                                                  13


                                                                                24.0
D.O. mg/L
pH
Sol. COD mg/L
Sol.TOC mg/L
Ortho P04 mg/L
Tot.P
NH3-N mg/L
Sol. Tot. KN mg/L
Tot.KN mg/L
SS mg/L
VSS mg/L
Sol.Mg mg/L
Sol.Ca mg/L
P/SS, Percent
—
6.3
180
75
9.8
10.6
23.9
26.0
28.0
112
-
12.4
25.0
-
0.2
6.5
75
35
30.7
192
23.8
_
224
3540
2550
15.8
26.0
4.6
5. High Flow Conventional PI
D.O. mg/L
pH
BODsmg/L
Sol. COD mg/L
Sol.TOC mg/L
Sol. Tot.P mg/L
Tot.P mg/L
NH3-N mg/L
Sol. Tot.KN mg/L
Tot.KN mg/L
N03-N mg/L
SS mg/L
VSS mg/L
Sol.Mg mg/L
Sol .Ca mg/L
P/SS, Percent

6~3
180
220
-
10.8
12.3
-
25.0
26.1
_
no
-
-
-
-
0.1
6.5

60
35
30.0
127
21.3
22.4
172
_
1815
1445
17.6
25.0
5.3
0.2
6.5
65
30
21.4
190
22.3
22.4
227
3535
2575
13.7
25.5
4.8
1.2
6.5
70
30
12.1
188
_
21.0
225
3450
2500
10.4
_
5.1
ug Flow Test
0.1
6.6
_
65
35
29.4
143
21.3
22.0
193
.25

-
17.3
25.0
-
0.3
6.7
-
65
30
18.0
148
19.8
20.2
203
_
2115
1640
14.8
25.0
6.1
0.3
6.7
60
35
11.5
130
20.9
21.0
208
2285
l64o
10.2
25.3
5.2
5.2
6.7
60
30
5.1
130
19.2
19. ^
198
2240
1650
8.7
24.2
5.5
7.2
6.8
60
30
3.6
125
18.3
19.0
200
2295
1640
8.4
25.0
5.4
System 12/10/69 -
1.4
6.7
-
60
30
8.4
145
17.8
18.4
197
_
_
_
_
23.5
-
4.7
6.7

50
30
4.2
149
16.0
16.8
205
_
2175
1680
10.2
25.0
6.7
5.7
6.8
_
50
30
3.6
145
14.1
15.8
205
.50

_
10.0
23.5

7.8
6.8
60
30
-
128
17.5
18.2
196
2325
1685
8.1
24.2
5.3
10:00
6.4
6.8
_
50
25

140
13.7
15.0
197
„
2200
1715
10.4
25.0
6.3
-
6.4
100
^5
41.5
510
23.0
23.5
>6oo
9730
7085
16.6
31.5
5.0
a.m.

6~4
_
130
^5
>50
>05
24.7
25.4
>6oo
•M
11230
8810
28.4
31.0
5.9
                                                                                 0.5
                                                                                 6.9
                                                                                  26
                                                                                  55
                                                                                  30
                                                                                 1.4
                                                                                15.7


                                                                                  15
                                      126

-------
                                   Table A-6
                                  (continued)


                           PROFILE ANALYTICAL RESULTS
                   PE   AT-1  AT-2  AT-3
                                                 AT- 5  "AT-5   AT-7
RS
SE
6.  Normal Control System 12/3/69 - 4:00 p.m., MLSS =  1850 mg/L,  P/SS = 5.4 percent
                                                                                 1.2
                                                                                6.8
                                                                                  10
                                                                                 45
                                                                                 35
                                                                                0.3
D.O.  mg/L

BODsmg/L
Sol.COD mg/L
Sol.TOC mg/L
Ortho P04 mg P/L
Sol.Tot.P mg P/L
Tot.P mg P/L
Sol.Tot.KN mg/L
Tot.KN mg/L
Sol.Mg mg/L
Sol.Ca mg/L

7.  Test System with Approach to Complete fixing 12/3/69 - 4:00 p.m., MLSS = 1830 mg/L,
                                                                     P/SS = 5.4 percent
                                                                                2.0
                                                                                6.8
                                                                                  7
                                                                                 35
                                                                                 35
                                                                                0.4
_
6.6
170
215
110
8.7
9.7
-
_
36.0
_
-
0.1
6.6
_
75
55
30.2
33.0
98
29.2
150
17.6
26.5
0.1
6.7
-
70
50
2k. 4
27. 0
97
28.6
156
16.8
27.8
0.3
6.8
_
55
1+0
16.3
18.8
98
26.2
154
14.0
26.5
1.0
6.8
_
50
35
5.5
6.2
98
21.6
152
11.0
25.0
3.6
6.8
_
4o
30
1.0
1.4
100
18.8
156
8.8
30.0
4.6
6.8
_
35
30
0.5
0.8
98
16.8
148
8.0
24.0
5.2
6.8
_
30
25
0.3
0.7
102
16.0
152
7.6
25.0
—
6.5
—
90
55
46.4
>50
520
27.0
516
17.0
30.0

D.O.
pH
BOD5
Sol.
Sol.

mg/L

mg/L
COD mg/L
TOC mq/L
Ortho P04 mg
Sol.
Tot.
Sol.
Tot.
Sol.
Sol.
Tot.P mg
P mg P/L






P/L
P/L


„
6.6
170
215
no
8.7
9.7
_
Tot.KN mg/L
KN mg/L
Mg mg/L
Ca mg/L



36.0
-
-

0.1
6.6
_
65
45
30.4
33.0
96
27.6
136
15.8
26.5

0.2
6.6
_
55
45
24.7
28.8
102
27.8
162
15.8
26.5

0.2
6.7
-
50
40
18.0
20.0
100
25.2
160
13.4
25.5

1.2
6.7
-
45
35
6.0
7.0
98
21.6
152
9.8
25.5

4.0
6.8
_
40
30
l.o
1.5
100
19.2
154
7.8
25.0

5.5
6.8
_
35
30
0.8
1.3
102
17.8
152
7.2
27.5

5.8
6.8
-
30
30
0.5
1.0
96
17.4
146
7.6
26.5
P/SS
_
6.5
-
90
55
44.6
>45
480
25.2
500
-
—
8.  Normal Control System  11/18/69 - 2:00  p.m.

D.O. mg/L
pH
BOD5mg/L
Sol.COD mg/L
Sol.TOC mg/L
Ortho P04 mg P/L
Sol.Tot.P mg P/L
Tot.P mg P/L
NH3N mg/L
Sol.Tot.KN mg/L
Tot.KN mg/L
SS mg/L
VSS mg/L
P/SS, Percent
M
6.3
160
185
75
6.8
8.0
10
30.0
33.5
34
130
83

0.1
_
—
125
50
25.1
27.5
110
28.0
29.9
144
1840
1480
4.5
0.3
_
_
75
40
_
17.7
108
24.6
26.0
146
1930
1460
4.7
1.0
_
_
75
30
6.7
6.8
106
20.6
22.6
134
1920
1520
5.1
2.0
-
_
60
35
1.5
2.0
108
18.8
20.6
136
1960
1460
5.4
4.5
-
_
60
25
_
1.1
114
18.0
19.0
148
2000
1500
5.6
5.5
-
_
45
30
o.l
0.5
106
16.8
18.4
132
2040
1610
5.2
6.0
-
_
55
30
0.1
0.3
120
17.0
18.3
156
2050
1610
5.8
-
-
_
100
50
15.0
15.4
-
24.0
25.6
-
8630
6190
-
2.5
7.0
8
55
30
0.1
0.6
0.8
17.5
19.2
-
13
-
-
                                       127

-------
                                   Table A-6
                                  (continued)
                           PROFILE ANALYTICAL  RESULTS
                   PE   AT-1  AT-2  AT-3   AT     AT-5

9.  Test System after Low P.O. Test 11/18/69 - 2:00 p.m.
RS
D.O. mg/L
pH
BOD5 mg/L
Sol. COD mg/L
Sol.TOC mg/L
Ortho P04 mg P/L
Sol. Tot.P mg P/L
Tot.P mq P/L
NH3N mg/L
Sol. Tot.KN mg/L
Tot.KN mg/L
SS mg/L
VSS mg/L
P/SS, Percent

6~3
160
185
75
6.8
8.0
10
30.0
33.5
34
130
83

0.1
_
_
80
45
-
12.6
90
23.4
25.1
130
1780
1410
4.4
0.2
_
_
75
35
16.6
18.2
88
23.8
25.3
131
1830
1530
3.8
10. Normal Control System 10/23/69
D.O. mg/L
pH
BOD5 mg/L
Sol. COD mg/L
Sol.TOC mg/L
Ortho P04 mg P/L
Sol. Tot.P mg P/L
Tot.P mg P/L
NH3N mg/L
Sol. Tot.KN mg/L
Tot.KN mg/L
N02+N03-N mg/L
11. Test System
D.O. mg/L
PH
80 D5 mg/L
Sol. COD mg/L
Sol.TOC mg/L
Ortho P04 mg P/L
Sol. Tot.P mg P/L
Tot.P mg P/L
NH3N mg/L
Sol. Tot.KN mg/L
Tot.KN mg/L
N02+N03N mg/L
.
6.6
150
230
95
8.5
-
12.0
33.9
_
_
<0.1
Du r i ng

6~6
150
230
95
8.5
,
12.0
33.9
_
_
-
0.1
6.7
-
125
60
23.5
>-
66
30.8
36.0
132
<0.1
Low D.
0.1
6.7

80
40
8.9
11.0
46
31.3
35.0
140
0.1
_
6.8
_
70
25
8.0
.6
67
26.6
33.0
130
0.1
0.4
_
_
60
40
7.6
7.8
88
21.4
23.5
130
1830
1410
4.4
- 2:00
.
6.8
_
70
30
1.5
_
62
23.7
28.2
130
0.1
1.0
_
_
55
30
0.1
0.6
86
19.2
20.4
132
1890
1530
4.6
p.m. ,
4.0
6.9

50
25
1.0
1.0
73
19.9
23.8
140
0.1
0. Test 10/23/69 -

_

140
60
12.7
,
41
30.9
33.0
130
0.1

_

90
50
11.0
_
36
28.9
29.6
126
0.1
0.1
6.9

80
45
10.0
_
39
26.2
27.0
125
<0.1
2.2
_
_
55
30
0.1
o.4
80
16.8
18.0
122
1840
1480
4.4
MLSS
.
7.0

55
25
0.8
_
77
18.4
22.2
140
0.1
2:00

_

80
4o
9.3
10.6
40
22.5
24.7
126
<"0.1
3.7
_
_
60
30
o.l
0.5
82
16.6
18.7
128
1880
1470
4.4
= 1890.

7.0

50
20
0.5
'.1.0
75
16.3
20.0
141
0.1
4.8
_
_
50
20
0.1
-
86
17.6
18.3
134
i860
1430
4.6

6.7
7.0

50
20
0.5

77
16.2
19.7
143
0.1
p.m. , MLSS =

_

70
35
10.8
_
45
20.7
24.1
145
0.1 -
0.3
6.9

75
35
11.8
T
45
20.3
24.0
143
£0.1

_
_
120
60
15.7
16.8
_
25.2
26.4
>290
8370
6350
-


6~8
_
115
55
19.7
f *™
175
20.7
26.5
_
<0.1
1930,

6~7

150
55
25.5

130
24.8
27.4
284
< 0.1
~sT
                                                                                 i.o
                                                                                 7.0
                                                                                  11
                                                                                  55
                                                                                  40
                                                                                 1.6
                                                                                 2.2
                                                                                 2.8
                                                                                18.8
                                                                                21.2

                                                                                  10
                                                                                 1.8
                                                                                 7.0
                                                                                   9
                                                                                  50
                                                                                  25
                                                                                 1.5
                                                                                15.^
                                                                                19.8

                                                                                 0.1
                                                                                 0.1
                                                                                 6.9
                                                                                  38
                                                                                  75
                                                                                  35
                                                                                10.8

                                                                                11.0
                                                                                19.8
                                                                                26.0
                                      128

-------
Table A-6
(continued)
PROFILE ANALYTICAL RESULTS

12. Normal Control
D.O. mg/L
pH
-•=80 D5 mg/L
Sol. COD mg/L
Sol.TOC mg/L
Ortho P04 mg P/L
Tot.P mg P/L
*ATP mg/L
NH3N mg/L
Tot.KN mg/L
,N02+N05N mg/L
"''SS mg/L
"VSS mg/L
P/SS, Percent
PE
AT-1
AT-2
System 9/17/69 -
0.0
6.5
247
210
110
8.7
12.0
0.03
12.0
30
0.04
175
120

13. Test System (After
D.O. mg/L
PH
*BOD5 mg/L
Sol. COD mg/L
Sol.TOC mg/L
Ortho P04 mg P/L
*ATP mg/L
NH3N mg/L
N02+N03N mg/L
-A-SS mg/L
-A- VSS mg/L
14. Normal Control
S.O. mg/L
pH
Sol. COD mg/L
Sol.TOC mg/L
Ortho P04 mg P/L
Sol. Tot.P mg P/L
Tot.P mg P/L
NH3N mg/L
Tot.KN mg/L
N02+N03N mg/L
0.0
6.5
241
210
110
8.7
0.04
12.0
0.04
190
110
0.0
6.7
151
100
_
21.7
88
1.36
12.0
150
0.23
2100
1475
3.2
0.1
6.8
48
70

11.5
94
1.90
11.5
155
0.12
2350
1575
3.5
AT-3
10:30
0.4
6.9
26
60
M
2.8
98
2.05
8.0
156
0.14
2500
1700
3.8
"A7I4"
a.m.
3.4
6.9
17
50
45
0.3
99
2.16
7.0
158
0.24
2400
1775
4.1
Low Flow Test) 9/17/69 -
0.0
6.8
120
80
80
10.2
1.02
11.0
0.14
2000
1250
0.1
6.9
60
65
•r-i
1.3
1.08
10.5
0.09
1725
1250
System 8/27/69 -

6?4
130
110
4.8
6.0
_
22.5
32
0.05
0.1
6.6
70
70
50.8
_
128
17.0
120
-

_
50
50
14.1
15.0
112
11.7
100
-
1.2
6.9
28
55

o~6
1.35
8.0
0.14
1750
1275
2:00

—
50
55
13.9
15.0
108
12.0
90
-
3.6
6.9
17
45
-
0.3
1.26
7.0
0.77
2000
1350
p.m. ,
6.0
6.8
60
50
13.7
13.8
108
12.3
95
2.00
AT-5
SVl =
5.5
6.9
17
45

0.1
102
2.46
5.5
158
1.39
2650
1750
3.9
10:30
5.4
6.9
14
50

0.2
1.31
6.0
1.07
1900
1350
MLSS =
.
-
70
60
-
13.2
118
12.3
84
-
AT-S
203
5.7
7.0
19
45
35
o.l
100
2.50
5.0
156
2.46
2575
1750
3-9
a.m.
5.6
7.0
13
45

0.3
1.44
4.5
2.15
1900
1300
2170,
_
-
70
65
-
-
112
12.7
92
-
AT- 7

6.1
7.0

55

0.1
106
2.46
4.5
164
2.49
2900
1950
3.7
SVl =
6.6
7.0
11
45
55
0.2
1.51
4.0
3.27
2000
l4oo
P/SS
4.9
6.9
50
50-
12.5
13.0
106
13.6
88
2.30
                                                                     RS
                                                                    0.0
                                                                    6.7

                                                                    130
                                                                     75
                                                                   21.7

                                                                    9.21
                                                                    8.5

                                                                   2.00
                                                                   12050
                                                                   8500
                                                               =  290
                                                                    6.6

                                                                     90
                                                                     60
                                                                   20.6

                                                                    7.5
                                                                   0.20
 SE
 1.2
 7.2

  50
  20
 0.1
 4.5

3.28
 1.6
 7.2

  50
  25
 0.3

 5.5
3.34
                                                                  4.7,  SVl  =  150


                                                                     6~8


                                                                      78
  1.3
  7.1
  50
 0.5
 0.5

 9~8
   12
 l.6o
Designates analyses performed by  Biospherics,  Inc.  under  FV/QA Contract  No.  14-12-419.
                                     129

-------
                                    Table A-6
                                   (continued)
                            PROFILE ANALYTICAL  RESULTS
                    PE   AT-1  AT-2  AT-3  "AT-4   AT-5   AT-6  AT-7      RS        PE

15.   Test System During High Solids Study 8/27/69 -  2:00^^.,  MLSS = 3200^


                                                                                  0.2
                                                                                  7.1
                                                                                   35
                                                                                   25
                                                                                  1.1
                                                                                  2.0

                                                                                  8.8

                                                                                 0.65
                                                                                  0.8
                                                                                  7.2
                                                                                  130
                                                                                   87
                                                                                  0.5
                                                                                 11.7
                                                                                   13
D.O
pH
Sol
Sol
. mg/L
.COD mg/L
.TOC mg/L
Ortho P04 mg
Sol
Tot
NH3
Tot
.Tot.P mg
.P mg P/L
N mg/L
.KN mg/L



P/L
P/L



N02N03N mg/L
16.
D.O
pH
Sol
Sol
Normal Control
. mg/L

.COD mg/L
.TOC mg/L
Ortho P04 mg
NH3
Tot
17.
D.O
pH
Sol
Sol
N mg/L
.KN mg/L




P/L


6~^
130
110
4.8
6.0
_
22.5
32
0.05
0.0
6.6
70
65
75.0
_
116
17.5
94
-
-
60
60
52.5
-
124
15.7
100
-
System 7/25/69 -
_
6.5
480
215
6.2
17.2
28
Test System During
. mg/L

.COD mg/L
.TOC mg/L
Ortho P04 mg




P/L
NH3N mg/L
Tot
18.
D.O
.KN mg/L

Normal Control
• mg/L
Ortho P04 mg
Sol
NH3
Sol
.Tot.P mg
N mg/L

P/L
P/L

.Tot.KN mg/L

6~5
480
215
6.2
17.2
28
0.0
6.8
240
133
19-5
19.8
30
Low D.
0.0
6.8
360
195
10.0
18.0
22
_
_
180
108
21.5
20.0
23
-
60
50
26.1
-
96
14.0
82
-
5:00
_
_
150
95
16.5
17.5
20
5.5
6.8
50
50
19.0
20.0
_
13-3
_
1.90
p.m. ,
0.3
6.8
150
95
9.8
17.0
16
0. Study 7/25/69 -

_
246
1V5
6.5
17.3
21
System 6/12/69 -

7.7
12.7
17.0
37
0.2
>25
41.7
21.3
3^

>25
38.1
19.2
32

_
205
110
5.0
15.5
18
4:00

24~5
27.6
20.0
30
0.1
6.9
180
115
3.0
16.0
17
p.m.
0.1
14.1
21.0
16.2
28
-
55
50
16.8
-
118
12.0
92
-
MLSS =
_
_
130
95
1.5
1^.5
16
5:00 p

_
185
110
^.5
12.5
16


11.8
_
15.9
28
P/SS
4o
50
19.0
-
_
12.2
-
-
2040
.
_
125
78
0.5
14.0
15
.m. ,

—
180
110
5.5
13.6
16

2.5
2.5

13.1
21
= 3
5
6


16
19

11

2.
SV
3
6
. 1 , SVI =275
.3
.9 6.7
45
50
.3
.0
- —
.8
- -
05
1 = 87
.5
.9 6.8
125

0
13

83
.5
.5

MLSS = 1930 SVI
0
6
.6
.9 6.9
185
1
5
11


4

0
12

15
.2
• 5
15

.9
• s
.5
.5
19
                                                                              = 68
                                                                                  7.0
                                                                                  200

                                                                                  5.0

                                                                                   17
                                                                                  0.3
                                                                                  o.U
                                                                                  8.0
                                                                                   14
                                        130

-------
                                    Table A-6
                                    (continued)


                             PROFILE ANALYTICAL RESULTS



                   ~PE~  "AtTT  "ATI2  Aflj   ~ATl4"  "AT^  "AT^S  AT-7     ~~RS~      ~SE~

19.   Test System at Normal  Operation 6/12/69 4:00 PM

                                                         l.o   1.9
                                                                                   0.3
                                                                                   0.4
                                                                                   8.0
                                                                                   16
D.O. mg/L - 0.1
Ortho P04 mg P/L 7.7 > 25
Sol. Tot. P mg P/L 12.7 40
NH3N mg/L 17.0 20.6
Sol. Tot. KN mg/L
20. Normal Control
D.O. mg/L
D.O. Uptake mg/L/hr
pH
Sol.TOC mg/L
Ortho P04 mg/L
NH3N mg/L
Al ka 1 i n i ty mg/ L
(to pH = 4.5)
21. Test System at
D.O. mg/L
D.O. Uptake mg/L/hr
pH
Sol. COD mg/L
Ortho P04 mg P/L
Tot.P mg P/L
NH3N mg/L
Alkalinity mg/L
(to pH = 4.5)
37 37
38
23. 4
36
System 5/20/69 -
0.1
74
6.6
67
- 17.5
- 15.2
225

0.0
13^
6.8
50
16.5
1^.2
188

Normal Operation
0.0
64
6.8
130
- 17.5
77
- 17.8
212

0.0
156
7.0
85
15.5
75
17.5
218

>25
36
21.0
33
10:00
0.0
59
6.9
U6
14.7
13.^
185

0.2
22.8
32
19.4
30
a.m.
0.1
60
6.9
41
6.7
12.5
197

5/20/69 - 1
0.0
70
7.1
65
9.5
75
15.7
208

0.1
63
7.1
45
4.5
74
15.0
202

20.4
17.3
29

0.2
17
7.0
45
4.0
11.9
178

:00 p.
0.2
60
7.2
50
6.3
73
14.1
205

l.o
5.4
7.2
12.0
22

3.9
20
6.9
36
0.2
10.5
185

m.
2.4
30
7.3
40
0.3
76
11.6
180

1.9
2.1
3.2
_
18

6.0
23
7.0
31
0.2
10.2
170


5.0
22
7.3
45
0.2
73
10.2
173

                                        151

-------
                             Table

                   Total  Inorganic
A-7

Carbon Results
Date
6/19/69
7/7/69
7/23/69
7/30/69
8/4/69
8/11/69
8/18/69
8/25/69
9/8/69
9/15/69
9/22/69
9/29/69
10/10/69
10/21/69
11/3/69
11/25/69
12/24/69
Average
Type
Sampl e
Compos i te
Compos i te
Compos i te
Compos i te
Grab
Grab
Grab
Grab
Grab
Grab
Grab
Grab
Grab
Grab
Grab
Grab
Grab

Sample Points^ mgC/L
PE
32
33
36
38
28
28
26
31
33
35
30
31
37
39
38
3^
30
33
AT-1
4o
45
32
45
35
35
28
36
33
42
39
33
40
38
40
43
35
37
AT- 2
40
45
48
52
34
34
32
37
32
42
39
34
40
39
40
41
36
39
RS-1
-
50
59
50
35
35
31
34
33
35
29
39
53
34
41
51
32
40
RS-2
-
53
62
58
35
34
32
33
25
37
30
36
42
40
39
42
39
40
SE-1
38
32
30
38
35
34
32
31
27
37
29
33
41
40
41
44
30
35
SE-2
43
33
31
36
32
32
40
32
20
37
29
30
41
41
41
40
30
35
Note:   Composite samples were stored daily collection and the results
       are questionable.  Grab samples were analyzed within one hour
       of collection time,  eliminating changes due to storage
                               152

-------
                            Table A-8

               Baltimore Phosphate Removal  Study

              Characteristics  of Wastewaters From
                  Sludge Handling Operations
                                               Total
Samp 1 e
Date
El
2/10/70
2/11/70
2/11/70
2/12/70
Time
utri ati
4 p.m.
1 1a.m.
4 p.m.
4 p.m.
Vacuum Fi
2/10/70
2/11/70
2/11/70
2/12/70
4 p.m.
1 1a.m.
4 p.m.
4 p.m.
Type
Total
mgP/L
on Wastewater
Total
Soluble
Total
Sol uble
Total
Soluble
Total
Sol uble
Iter Fil
Total
Soluble
Total
Soluble
Total
Soluble
Total
Soluble
85
57
64
57
60
53
60
51
SS
mg/L
2840
930
800
950
VSS .
mg/L
1890
800
700
740
COD
mg/L
760
740
760
730
Kjeldahl
Ni troqen
mg/L
>210
195
>210
205
205
188
196
190
Magnesium
mg/L
24.0
17.0
22.0
16.6
18.6
16.6
21.0
18.0
Cal ci urn
mg/L
100
37
56
35
56
20
56
41
I ron
mg/L
59
0.8
23
1.5
24
1.2
21
1.3
trate Wastewater
24
16
24
19
26
21
26
19
820
320
450
520
550
290
380
420
165
175
165
175
58
42
58
50
61
52
63
52
16.6
15.0
16.2
15.6
16.6
16.6
18.0
16.1
58
20
51
42
51
45
58
45
20
0.5
12
0.7
10
0.7
12
1.0
Note:   For normal operation of 2 vacuum filters the Elutriation wastewater
       averages 1,500-1,800 gpm, and the Fi1trate wastewater averages
       600-800 gpm.  During average operation, polymer was added for condi-
       tioning, and the vacuum filter product was about 20% solids cake
       from a 3-4% solids elutriated sludge stream.
                                133

-------
              Table A-9

, Baltimore Phosphate Removal Study
       Air Supply Rates for
 Rapid Dissolved Oxygen Variation Test
           System No. 2
Date

11/10/69
11/11/69


11/12/69


11/13/69



11/14/69


11/15/69


11/16/69
11/17/69
11/18/69

Time

12:00 Noon
3: 15 p.m.
5:45 p.m.
11:30 p.m.
8:30 a.m.
11 :00 a.m.
3:30 p.m.
12:15 a.m.
10:45 p.m.
5:00 p.m.
11 :00 p.m.
7:00 a.m.
6:15 p.m.
7:00 p.m.
6:00 a.m.
9:15 a.m.
6:00 p.m.
5:30 p.m.
7:30 a.m.
1:15 a.m.
8:45 a.m.
Air Supply
SCFM
8,800
6,000
4,400
8,800
14,800
8,700
4,400
7,700
8,800
4,300
7,800
12,500
7,400
4,100
8,000
9,500
9,100
5,000
9,100
5,100
9,000
Change


Down
Down
Up
Up
Down
Down
Up
Up
Down
Up
Up
Down
Down
Up
Up
Down
Down
Up
Down
Up
                                   System No.  1
                                    Air Supply
                                       SCFM

                                       7,800
                                       10,700
                                       12,900
                                       7,900
                                       13,000
                                       7,800
                                       12,500
                                       9,000
                                       7,800
                                       12,800
                                       8,800
                                       14,100
                                       9,100
                                       13,100
                                       9,300
                                       7,500
                                       8,300
                                       12,600
                                       8,200
                                       12,600
                                       8,300
  Number
of Blower
Operat ing
    1
    1
    1
    1
    2
    1
    1
    1
    1
    1
    1
    2
    1
    1
    1
    1
    1
    1
    1
    1
    1

-------
                   Table A-10

       Baltimore Phosphate Removal Study
Summary of Oxidation Reduction Potential Results

              ORP at Outlet From Test Aeration Tank
  Date              Average              Range
                  Millivolts          Millivolts

11/1V69             370              200 - 490
11/15/69             350              130 - 510
11/16/69             505              460 - 530
11/17/69             440              265 - 520
11/18/69             435              230 - 515

11/24/69             565              560 - 570
11/25/69             565              560 - 570
11/26/69             570              565 - 575
11/27/69             565              560 - 570
11/28/70             545              540 - 560
11/29/70             550              545 - 555

12/2/69              505              465 - 530
12/3/69              530              515 - 545
12/4/69              535              525 - 545

12/8/69              540              515 - 545
12/9/69              535              495 - 550
12/10/69             535              525 - 545
12/11/69             540              495 - 550
12/12/69             540              535 - 545
12/13/69             545                 545
12/14/69             505              475 - 545
12/15/69             510              495 - 520
12/16/69             525              515 - 530
12/17/69             515              505 - 530
12/18/69             505              495 - 515
12/19/69             505              500 - 510
12/20/69             505              500 - 510
12/21/69             505              500 - 510
12/22/69             505              500 - 510
Note:  The above Eh values for ORP were determined by
       correcting the Ag, AgCI half-call  results by
       +197 mV to the instrument  reading.

                  135

-------
                                                                                                 Table A-ll

                                                                                      Baltimore Phosphate Removal  Study

                                                                                Laboratory Batch Study on Effect  of Suspended
                                                                                        Solids on Phosphorus  Removal
                                                                                                                                                     Centrifugal  (Soluble)
CT\
Time
minutes
Test Number
O1
2
10
20
30
UO
60
90
120
5UO
1POO
Test Number
O1
2
in
20
w
1*0
60
90
120
180
5UO
1200
Test Number
O1
2
10
20
}0
UO
60
QO
120
180
SUO
1200
£H

1

7.1
—
—
7-5
—
7.5
—
7.8
7.5
7.9
2

7.3
— .
—
7.7
—
7.8
—
8.0
7.8
7.8
8.5
?

7.4
	
—
7.8
—
7.8
-.J
8.0
—
8.0
8.5
Dl ssol ved
Oxygen
mg/L
1.1
6.4
6.4
3.2
6.U
6?5
2.0
6.3
6.0
D.O.
Uptake
mg/L/m
120
60
"54
20
102
54
33
18
IT
12
30
25
18
15
Total
Suspended
Solids
mg/L
3,140

2,980
3,160

2.9TO

2,050

1,81*0
2,100

1,800


1,250

1,000
1,030

1,010
960
Volati le
Suspended
Sol Ids
mg/L
2,410

2,340
2.3TO

2,260

1,650

1,450
1,660

1,1*10


8TO

8TO
840

T60
TOO
Total
Phosphorus
mg/P/L
102
101*
62
72
64
40
40
38
Total
Kjeldahl
Ni t rogen
mg/N/L
142
135
82
92
81*
52
52
55
48
Total
ATP
mg/L
1.44
1.75
1.81
1.99
2.16
0.81*
0.86
1.01
1.08
LOT
Total
Phosphorus
mg/P/L
15.2
32.0
22.1
10.8
2.5
O.I*
O.U
0.3
0.1*
0.5
1.4
10. T
14.6
9.4
U.I*
1.2
0.7
0.3
0.3
0.3
0.1*
1.3
7.7
8.3
7.7
4.9
3.0
2.2
1.2
0.5
0.3
O.U
0.8
1.1
Ortho
Phosphate
mg/P/L
13.0
29-9
20.0
8.7
1.9
0.3
0.2
0.1
0.1
0.2
1.4
9.3
14.5
9.3
3-5
1.0
0.5
0.2
0.2
0.2
0.2
1.2
6.6
8.2
7.5
4.7
2.8
2.0
1.1
0.5
0.3
0.2
O.U
o.q
BOD
mg L
117
50
34
116
52
31
33
115
33
~36
COD
mg/L
TO
68
66
62
59
56
54
51
50
62
TO
6T
6T
65
62
56
54
50
U8
48
155
68
62
5T
50
55
50
48
50
kfi
Total
Carbon
mg/L
70
30
30
30
30
25
20
20
15
69
35
30
31
30
25
20
15
10
10
69
40
Uo
30
30
30
30
25
25
20
in
Total
Kheldahl
Nitrogen
mg/L
27.5
20.0
18. U
16.0
15.0
13.8
13.2
11.6
11.0
8.6
7.4
22.7
17.4
15-2
1U.8
14.2
13.6
12.8
12.2
11.4
9.2
7.4
21.6
17.2
16.4
16.2
15.8
15.2
14. 8
14.2
12.0
12.0
11.0
Q n
Ammonia
Nitrogen
mg/L
20.1
12.5
11.7
10. U
9.8
9.4
8.7
8.2
6.3
5.0
18.5
12.0
11. U
11. U
11.1
9.8
9.2
7.9
7.0
7.2
IT. 2
11. T
12.5
11.5
12.3
11. T
11.1
10.6
8.8
9.2
8.3
Nl trata
and
Nitrate
Nl t rogen
mg/L
0.10
0.10
0.10
0.10
0.20
o.Uo
O.TO
1.00
4.60
6.00
.05
.05
.08
.20
.22
.32
.44
.46
.98
2.80
5.50
   Note: 1lnitlal Computed Values  Include  Some  Effects of  Primary  Effluent  Suspended  Solids.

-------
                        Table A-12

           Baltimore Phosphate Removal Study

Laboratory Data For Tests To Maintain Phosphorus Removal

                        Total Phosphorus Removal,   percent
Test
Date
Ful 1 -Scale
Removal
Time From
Start-up
2
k
6
8
10
12
]k
16
18
20
22
2k
26
28
30
32
3k
36
38
ko
k2
kk
k6
k8
52
56
58
62
70
7k
80
1
10/7/69

86





26



67



95



88




78



70


90



2
12/3/69

90






50






63




89





8k



82

8k

90
3 k
10/28/69 11/6/69

Sk 95


38
62
81
86
8k
80 8k
81
82
77
68
65
77 56
k6
38
3k
26
19
81 33
28
26



83



81

77

5
11/25/69

89


82
83
78
68
63
66
66
68
_
51
5k
k7
k7
k2
35
3k
32
30
27
23
17
7

11
17
19


16
10

6
10/23/69

89



83
84
8k
7k
81
79
72
68
58
51
k8
56
60
38
15
23














 Note:  Test 1 - Plug Flow Without Sludge Wasting
        Test 2 - Plug Flow With 2%/Day Sludge Wasting
        Test 3 - Plug Flow With 6 hr. Settling
        Test k - Complete Mixing - 6 hr Aeration, 2 hr. Settling
        Test 5 - Step Aeration - Feed At Beginning, 1/3 and 2/3 points of A.T.
        Test 6 - Contact Stabilization - 2 hr Contact, k hr Stabilization

                            137

-------
                               Table A-13

                Baltimore Phosphate Removal  Study Operation

                 Observation of Metal  Variations With Time
                                                           Metal  Ions
Date

2/9
2/10
2/11


2/12





2/13


2/26

2/27



2/28



3/1

and Time

11
5
4
6
10
2
6
10
2
6
10
2
6
10
9
11
9
3
6
11
8
5
9
10
9
1

:30
:00
:00
:00
:00
:00
:00
:00
:00
:00
:00
:00
:00
.00
:00
:30
:00
:00
:00
:30
:30
:00
:00
:30
:00
:00

P.
P.
P-
P.
P.
a.
a.
a.
P-
P.
P.
P.
P.
a.
P.
P-
a.
P-
P.
P.
a.
P.
P.
P.
a.
P.

m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
m.
Total P Or thro P
MgP/L mg/L
9.2/4.6
5.2/0.6
6.2/1.8
6.6/1.6
6.8/2.0
6.5/3.4
4.8/8.6
3.8/9.2
5.7/7.5
7.2/6.8
13.8/6.6 6.9/6.2
6.5/6.1
5.8/2.0
8.4/3.5 5.2/3.4
7.4X.3
7.7X.3
6.4/.S
7.5X.3
8.9X.2
16.5/0.5 S.4/.3
13.5/1.0 7.4/.9
19.5/1.5 8.6/0.2
8.8/0.2
20.0/0.8 8.6/0.5
10.2/1.7 6.8/1.5
7.5/0.8 6.0/.7
COD
mg/L
270/60
155/50
210/65
240/55
450/65
190/70
370/65
160/65
370/80
285/65
490/70
355/70
270/85
300/70
405/75
420/70
295/75
365/65
410/70
450/80
325/75
350/75
470/60
435/85
265/85
285/85
Mq++
mg/L
9.9/9.4
11.7/8.4
12.0/10.8
11.7/11.4
11.4/11.1
10.7/11.0
10.8/11.0
12.4/11.8
12.4/12.2
11.7/12.4
11.5/12.4
11.2/11.7
11.2/10.0
11.9/9.8
9.2/8.4
9.4/8.4
10.6/86
13.0/7.8
13.2/8.8
12.0/9.4
13.4/9.7
9.6/9.4

9.8/8.8
9.8/9.2
10.4/7.2
Ca++
mg/L
29

37
34
32
31
31
36
35
31
31
31
31
32
26
26
26
26
27
26
30
25

30
26
27
.0
-
.4
.4
.0
.0
.0
.4
.0
.4
.4
.4
.0
.0
.6/26
.0/28
.6/26
.6/26
.0/26
.6/26
.0/26
.0/27

.0/30
.0/26
.0/26














.6
.0
.0
.6
.6
.6
.6
.0

.0
.0
.0
Fe++ +
mg/L
-
-
-
.86
1.05
1.55
1.25
.74
.46
.70
.46
1.13
.77
-42/<.1
2.6
1.92
1.28
1.52
1.62
1.82
1.38
1.94

1.52/.58
.76
.78
Note:   The data in this table refer to concentrations in the Primary Effluent
       and the Secondary Effluent from System No.  1  (PE/SE 1).  Where only one
       value fs shown it refers to Primary Effluent.
                                     138

-------
Minimum
Biological












H
VjJ
VO










Date
of
Week

7-14
7-22
7-29
8-4
8-n
8-18
8-25
9-2
9-8
9-15
9-22
9-29
10-7
10-14
10-20
10-28
11-3
11-10
11-17
11-24
12-1
System Total
Phosphorus
Removal
percent
37
83
52
69
90
81
88
82
74
87
81
73
74
91
47
92
94
93
87
91
83
Requirement
(P/BOD=0.01)

mg/L
4.6
9.7
6.0
7.0
8.5
7.8
6.8
7.5
9.7
10.4
8.7
9.6
8.3
9.2
5.6
12.4
10.2
10.6
10.5
13.1
9.2
BOD5
mg/L
175
114
167
143
160
101
146
120
138
221
174
80
137
174
106
179
153
174
182
149
165
P
mg/L
1.8
l.l
1.7
1.4
1.6
1.0
1.5
1.2
1.4
2.2
1.7
0.8
1.4
1.7
1.1
1.8
1.5
1.7
1.8
1.5
1.7
                                                                                       Table A-l4



                                                    Phosphorus Removal Accountability by Theoretical Metal and  Biological  Requirements




                                                                  System  No. 1 - Control - Weekly Average








                                                                               POSSIBLE PHOSPHORUS REMOVAL  BY  METALS
Average
            79
                                    1.5
Ca 1 c I um
(P/Ca-=0.52)
Ca
mgjl
5.6
(1.7)
8
2
.9
1.0
5.5
(1.7)
(1.7)
2.5
(1.7)
4.5
3.0
2.5
1.7
6.7
1.7
1.7
1.7
2.5
(1.7)

P
mg/L
2.9
0.9
4.2
1.0
0.5
0.5
2.9
0.9
0.9
1.3
0.9
2.3
1.6
1.3
0.9
3.5
0.9
0.9
0.9
1.3
0.9
1.4
Magnesium
(P/Mg=0.86)
Mg
mg/L
2.9
.3
1.5
1.0
5.3
1.8
1.2
1.5
0.7
1.2
3.1
2.5
4.4
5.5
2.0
2.2
4.2
5.9
4.3
6.2
7.0

	 P
mg/L
2.5
.3
1.3
.9
4.6
1.5
1.0
1.3
0.6
1.0
2.7
2.2
3.8
4.7
1.7
1.9
3.6
5.1
3.7
5.3
6.0
2.7
Iron
(P/Fe-
Fe
mg/L
2.6
1.4
1.4
1.7
1.9
0.9
1.7
3.8
2.1
0.8
6.1
4.3
3-1
3.6
1.5
1.9
1.0
0.4
1.8
2.4
3.6

=0-5?)
	 P
mg/L
1.4
0.8
0.8
0.9
1.0
0.5
0.9
2.1
1.2
0.4
3.3
2.4
1.7
2.0
.8
1.0
0.6
0.2
1.0
1.3
2.0
1.3
Aluminum
(R/A1-1.14)
Al
mg/L
1.6
1.3
2.0
2.5
1.8
1.5
1.1
1.6
2.1
1.1
1.1
3.3
l.l
1.4
.7
0.3
1.6
1.6
1.6
.5
1.0

P
mg/L
1.8
1.5
2.3
2.9
2.0
1.7
1.3
1.8
2.4
1.3
1.3
3.8
1.3
1.6
0.8
0.3
1.8
1.8
1.8
0.6
l.l
1.7
Coppe r
(P/Cu=0.48)
Cu
mg/L
0.2
0.2
0.1
0.2
0.2
0.1
0.6
0.3
0.3
0.2
0.3
0.5
0.8
0.3
0.3
0.1
0.3
0.3
0.3
0.3
0.3

P
mgTL"
0.10
0.10
0.05
0.10
0.10
0.05
0.30
0.10
0.10
0.10
0.10
0.20
o.4o
0.10
0.10
0.05
0.10
0.10
0.10
0.10
0.10
0.1
Zinc
(P/Zn=0.47)
Zn
mg/L
0.5
1.1
0.4
0.5
0.4
0.3
0.5
0.7
0.8
0.4
0.7
1.4
0.8
1.8
0.3
0.9
0.7
0.7
0.7
0.7
0.7

P
I^TL
0.20
.50
0.20
.20
.20
.10
.20
.30
.40
.20
.30
.70
.40
.80
.10
.40
.30
.30
.30
.30
.30
.3
Accountabil Ity
Total
	 P
mg/L
10.7
5.2
10.5
7.4
10.0
5.3
8.1
7.6
7.0
6.5
10.3
12.4
10.7
12.2
5.5
8.9
8.8
10.1
8.6
10.4
12.1

Difference
P
SiTL"
+6.1
-4.5
"4.5
+0.4
+1.5
-2.5
+2.3
+0.1
-2.7
-3.9
+1.6
+2.8
+2.4
+3.0
-0.1
-3.5
-1.4
-0.5
-1.9
-2.7
+2.9
                                                                                                                                                          9.0
                                                                                                                                                                           +0.2

-------









H

















Date
of
Week

7 -1U
7-22
Y-2'4
N-l<
M-n
8-18
8-25
9-3
'->-«
9-15
9-22
9-29
10-7
10-1 It
10-20
10-28
11-J
11-10
11-17
11-21*
12-1
12-6
12 -11
12-18
System Total
Phosphorus
Remove 1
percent
U
21
21*
67
75
72
82
85
88
83
89
91
89
86
18
39
9>»
1*9
61
77
81*
88
78
32

mg/L
1.6
2.5
2.8
6.8
7.1
6.9
6.3
7.8
11.6
9.9
9-5
11.8
9-9
8.7
2.2
5.3
10.2
5-6
7.3
11.1
9.1
9-3
8.1*
3.8
M 1 n 1 mum
B 1 o 1 og 1 ca 1
Requi foment
(P/BOD-0.01)
BODS
mg/L
172
99
162
lUl
161*
103
ll*l
nit
153
229
18U
91
114*
171
97
168
151*
173
183
11*9
165
161
130
193
P
mg/L
1.7
1.0
1.6
1.1*
1.6
1.0
1.1*
1.1
1.5
2.3
1.8
0.9
1.1*
1.7
1.0
1.7
1.5
1.7
1.8
1.5
1.7
1.6
1.3
1.9
                                                                                         Table A-lk
                                                                                        (cont inued)

                                                      Phosphorus  Removal  Accountability by Theoretical Metal and Biological Requirements

                                                                      System No.  2 - Test - Weekly Average



                                                                                  POSSIBLE PHOSPHORUS REMOVAL BY METALS
Ca 1 c 1 urn
(P/Ca-0.52)
Ca
mg/L
6.6
(2.1)
5-0
5.0
.5
1.0
i*.o
(2.1)
3.6
.8
(2.1)
3.5
(2.1)
i*.o
2.1
6.3
2.1
2.1
2.1
3.0
1.7
0.5
1.0
(2.1)
P
mg/L
3.1*
1.1
2.6
2.6
0.3
0.5
2.1
1.1
1.9
0.1*
1.1
1.8
l.l
2.1
1.1
3.3
1.1
l.l
l.l
1.6
0.9
0.3
0.5
1.1
Hagnesi urn
(P/Hg-0.86)
Hg
mg/L
2.2
.3
0.8
2.8
l*.8
2.5
1.8
0.3
1.0
1.8
2.1*
2.8
3.6
5.0
0.2
(2.3)
3.5
1*.6
2.7
5.1
9-8
2.6
1.5
(2.3)
	 p
mg/L
1.9
0.3
0.7
2.1*
lt.1
2.2
1.5
0.3
0.9
1.5
2.1
2.1*
3.1
1*.3
0.2
2.0
3.0
i*.o
2.3
lt.lt
8.1*
2.2
1.3
2.0
1 ron
(P/Fe-0.55)
Fe
mg/L
2.3
0.1*
1.7
1.8
2.1
1.0
2.0
3.5
3.0
2.7
6.1
1*.3
3.1
5.9
2.4
0.5
0.6
0.7
2.1*
2.1*
3.6
2.2
4.7
2.5
	 P
mg/L
1.3
0.2
0.9
1.0
1.2
1.5
1.1
1.9
1.7
1.5
3A
2.1*
1.7
3.2
1.3
0.3
0.3
0.1*
1.3
1.3
2.0
1.2
2.6
1.1*
Aluml num
(R/AI-l.ll*)
Al
mg/L
1.6
1.0
2.0
0
1.0
0
0.9
1.6
2.1*
2.1
1.1
3.3
l.l
l.l*
0.7
0.3
1.6
1.6
1.6
0.5
1.0
1.0
2.5
O.l*
	 p
mg/L
1.8
1.1
2.3
0
1.1
0
1.0
1.8
2.7
2.1*
1.3
3.8
1.3
1.6
0.8
0.3
1.8
1.8
1.8
0.6
1.1
1.1
2.9
0.5
Copper
(P/Cu=0.1*8)
Cu
mg/L
.2
0.2
0.2
0.2
0.2
0.1
0.6
0.3
0.3
0.2
0.3
0.5
0.8
0.3
0.3
o.a
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
	 P
mg/L
0.1
0.1
0.1
0.1
0.1
0.05
.3
.1
.1
.1
.1
.2
.1*
.1
.1
.05
.1
.1
.1
.1
.1
.1
.1
.1
Zinc
Zn

.5
1.0
0.1*
0.1*
0.5
0.1*
0.5
0.6
1.0
0.7
0.8
1.5
0.8
1.8
0.6
0.8
0.8
0.8
0.8
0.8
0.8
0.8
0.8
0.8
p
mg/T
0.2
.5
0.2
0.2
0.2
0.2
0.2
0.3
0.5
0.3
0.1*
0.7
0.1*
0.8
0.3
O.lt
O.lt
0.1*
0.1*
0.1*
0.1*
0.1*
0.1*
0.1*
Accountabl 1 1 ty
Total
p
mg/L
10.1*
4 5
B'.U
7.7
8.6
l*.5
7.6
6.6
9.3
8.5
10.2
12.2
9.1*
13.8
1*.8
8.1
8.2
9.5
8.8
9.9
11*. 6
6.9
9.1

Difference
p
mg/L
+8.8
+1.8
+5.6
+0.9
+1.5
-2.1*
+1.3
-1.2
-2.3
-1.1*
+0.7
+O.lt
-0.5
+5.1
+2.6
+2.8
-2.0
+3.9
+1.5
-1.2
+5-5
-2.lt
+0.7
+3.6
Average
            66
                     7.3
                                    1.5
                                                          1.1*
                                                                          2.1*
                                                                                           1.1*
                                                                                                           1.5
                                                                                                                             .1
                                                                                                                                            0.1*
                                                                                                                                                                               +1.1*

-------
                                                         Table A - 15

                                               Baltimore Phosphate Removal Study

                                                 BOD of Wastewater Samples
                                        Normal and Nitrification - Inhibited Values
H
Date

11/12/69


11/11/69


11/10/69


9/11/69


9/10/69

Sample
Sou rce*

SE1
SE2
PE
SE1
SE2
PE
SE1
SE2
PE
SE1
SE2
PE
SE1
PE
Normal
BODq
mg/L
7
9
195
6
5
160
4
2
150
22
27
190
29
170
BOD
BOD?o
mg/L
80
98
445
88
86
410
87
82
415
65
80
410
92
380
Ni tri f i cation
Inhibi ted
With Thiourea
BODq
mg/L
6
12
205
7
5
160
4
2
155
18
25
195
22
165
BOD?o
mg/L
21
29
260
20
16
245
12
11
235
40
44
270
40
280
Avg
mg/L
7
11
200
7
5
160
4
2
155
20
26
145
26
170
In!
COD
(Auto)
mg/L
55
60
270
55
50
295
50
50
320
60
55
305
70
275
tial
TOC NH3-N
mg/L mg/L
35 13.6
40 14.3
130 23.2
40 18.4
40 18.2
145 29.5
40 18.0
40 17.2
160 29.4
7.6
3.0
20.5
30 9.5
90 16.0
Observed Increase
In N03-N Over 20 Days
Normal
mg/L
14
15
41
22
22
40
24
21
60
15
-
43
21
57
I nhibi ted
mg/L
1
<1
<6
^1
<1
<6
1
1
<6
2
-
<3
< 1
<-3
Computed
Oxygen Need
For Ni trate
Formation
mgO/L
61
68
178
100
100
173
107
93
265
61
-
194
95
260
Di fference
Between Normal
and Nitrated
BOD2n Value
mgu/L
59
69
185
68
70
165
75
71
180
25
36
140
52
100
     •<''SE1   is  Secondary  Effluent  from  System  No.  1
      SE2   is  Secondary  Effluent  from  System  No.  2
      PE    is  Primary  Effluent

-------
                            APPENDIX B

        INSTRUMENTATION SYSTEM FOR  SIMULTANEOUS MONITORING
         FOR MULTIPLE CHEMICAL PARAMETERS AT THE BALTIMORE
                      ACTIVATED SLUDGE PLANT

                           Introduction

The application of extensive continuous monitoring  instrumentation to the
activated sludge biological treatment process  for wastewater  is very
limited at this time.  Conservative activated  sludge design has been the
traditional approach to handle a variable inlet feed stream to the pro-
cess and yet accomplish an acceptable range of quality of treated ef-
fluent.  However, the current demands for consistently high effluent
quality and for optimized process performance  are much greater.  To
meet these demands, the new application of monitoring instrumentation is
needed to provide immediate information readout so  that timely, appro-
priate process changes can be made  to maintain optimum process perform-
ance.

The following information describes an extensive instrumentation system
installed at the activated sludge portion of the Baltimore, Maryland
Back River Wastewater Treatment Plant which was operated from June to
December 1969.  The automatic sampling and analytical instrumentation
will first be described, and then typical recorded  data output will be
presented.  Finally, the problems associated with the sampling and analy-
tical instrumentation and the application of such systems for permanent
installation at activated sludge plants will be discussed.

                 Description of Monitoring System

The overall monitoring system was designed for continuous operation with
automatic hourly retrieval at as many as eleven sample points located at
various parts of the treatment plant.  The parameters measured were:  pH,
turbidity, total dissolved carbon,  dissolved COD, nitrite-nitrate, am-
monia, orthophosphate, and, on a less frequent basis, total phosphate
and total Kjeldahl nitrogen.  Other parameters measured by manual methods
were:  suspended solids, BOD, and specific metal ions.  These samples
for manual determination were collected and handled in a specially-
designed, completely-automated and  refrigerated sampling system.  The
sensors, automated wet-chemical procedures, and sample collection opera-
tions were coupled in a completely  synchronized operation.

The eleven sampling points (specific locations are  shown in Figure B-l)
were:

     Two in the effluent from the two secondary clarifiers
     (Sample Points 1 and 2)
                               143

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     One at the influent to the aeration system  (Sample Point  3) .

     Six in the aeration tanks, sampling the beginning  (Sample
     Points 4 and 5), the middle (Sample Points  6 and 7), and
     the end (Sample Points 8 and 9) of each of  the two aeration
     Tanks.

     Two in the return sludge flow in the control building  (Sample
     Points 10 and 11).

The activated sludge plant was modified so that  it consisted of two  separate
10 mgd treatment facilities, to provide one system that could be operated  on
a normal operating basis, while test conditions  could be imposed on  the  sec-
ond system.  The analytical systems were installed in the central control
building, with the most distant sampling point being approximately 400 feet
away.  One inch diameter polyethylene tubing was used to transport the
wastewater from the sampling point to the analytical complex.  Submersible
1/5 HP pumps mounted approximately two feet below the surface at each sample
point and supported on a metal bracket provided  a 4-6 gpm continuous-flow
sample stream.   Three-way valves were mounted on each of the sample  trans-
mission lines so that the system could be backwashed with a hypochlorite
solution on a weekly basis.

At each of the 6 sampling points located in the  aeration tanks, dissolved
oxygen sensing probes were mounted on the submersible sampling pumps.  Two
additional oxygen sensing probes were mounted in the supernatant liquid,
approximately one foot under the surface in each of the two final clarifiers.
The dissolved oxygen probes were Weston and Stack units consisting of a Model
A-40 dissolved oxygen monitoring probe and a Model A-25 cleaner-agitator
device.  The electrical signals from these probes were transmitted to a
Weston and Stack Model 3000 analyzer and switching unit and then to  a Leeds
and Northrup Speed-0-Mac, Model H, multi-point recorder for data readout.

A flow diagram of the entire sampling switching  and analysis system  is pre-
sented in Figure B-2.  All sample lines and fittings from the submersible
sampling pumps located at individual sampling points to the main overflows
in the sampler building were sized at one-inch diameter so that the  4-6  gpm
sample stream flow could be maintained.  Sample  stream flow through  the
remainder of the system beyond that point was reduced to approximately 1/3
gpm due to the use of 1/4 in. diameter Solenoid  valves and reduction of
other lines and fittings to 1/2 in. diameter.  The sample line flushing
system that was used on a once-a-week basis consisted of a 200-gallon poly-
ethylene tank and a 1/20-HP pump that provided a flushing flow of 8  to 10
gpm through the negative head system.  The in-line "Y" strainers were flushed
out on a daily basis.

The sample stream switching and sample collection activities of the  system
were provided by a TAFI (Technical Associates For Industry, Inc.) automatic
sampling system Model KS No. 569-  The system consisted of manifold

                               144

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three-way solenoid valves, the necessary programmer and timers to operate
these valves, a Buchler polystatic pump Model  2-6100  for sample collec-
tion pumping to a Buchler Model 3-4008V refrigerated  automatic fractional
collector.

The sample switching system diverted all streams  to waste except the one
stream being sent through the analytical train.   The  system was operated
on a one- or two-hour cycle, and at the end of each cycle, a tap water
flush was put through the system to minimize sample carryover.  Actual
sample collection took place during the last minute of each sampling
increment and was accomplihsed by collecting approximately 35 ml of
sample in a refrigerated 50 ml test tube.  The collector had a capacity
of 200 glass collection tubes.  The sample collection pump operated
continuously, with the stream being diverted to waste except during
actual sample collection.

The main single sample stream flow passed through pH  and turbidity sensing
units.  The pH output was provided by a recording pH  meter producing an
output in a strip chart recorder form.  The pH probe  was placed in a sys-
tem overflow point providing constant liquid depth and adequate mixing.
The turbidity measurement was provided by a Jacoby-Tarbox, Model A2
turbidimeter.  The turbid sensing unit provided a flow cell with a 1/2
in. light path.  The turbidity output was recorded on an Esterline-
Angus Model A601C single-channel curviliner recorder.  The turbidity
flow cell had a simple clamp design, permitting rapid cleaning of
windows.  Cleaning was conducted approximately on a semi-weekly basis.

At the over-flow point in the sampling system  where the pH probe was
located, a continuous sample stream of approximately  7 mls/min. was
pumped to the principal analytical instrumentation complex.  Alternate
sample introduction with distilled water-wash  periods between peaks was
selected to minimize sample carry-over, to improve analytical perform-
ance, and to aid in the identification of individual  samples.  This
method of sample introduction was achieved by  using a 4-way solenoid
valve that normally directed distilled water into the analytical system
and diverted the sample stream to waste, except for the last two minutes
of each cycle, when the sample stream was introduced  into the analytical
system.  A second solenoid valve was used to introduce a common standard
solution for all the analytical systems.  The  analytical standard 3-way
solenoid was actuated at the same time the tap water  valve was operated
in the TAFI switching system, to provide the cyclic flushing.  The
standard supply was stored in the refrigerated sample collection device,
minimizing degradation so that a replacement frequency of once every
two days was adequate.  Polyethylene tubing (0.34 inches in diameter)
was used to deliver the intermittent sample and distilled water stream
to the individual analyzers.

The four basic Technicon Auto-Analyzer automatic wet  chemistry systems
that were used on a continuous basis provided  analytical results for
ortho-phosphate, ammonia nitrogen, combined nitrate and nitrite and

                                145

-------
COD, and the output was received on two 2-pen continuous recorders.   The
ortho-phosphate was determined using Technicon Industrial Method  2-68W
employing the ammonium molybdate and ammonia naphthol sulfonic acid me-
thod with a full-scale recorder output range of 0 to 30 mg/L phosphorus.
The ammonia concentration was determined with the Technicon Industrial
Method 19-69W, utilizing the alkaline phenol-hypochlorite reaction with
ammonia, adapted for a concentration range of 0 to 50 mg/L ammonia nitro-
gen.  Combined nitrate and nitrite nitrogen was  determined by Technicon
Industrial Method 32-69W that involved an approximate 15-minute digestion
procedure with a potassium dichromate-sulfuric acid digestion mixture and
adapted to provide a full-scale range of 0 to 300 mg/L COD.

Another means of measuring organic matter was the use of a Union  Carbide
Model 1212 Total Carbon Analyzer on a continuous basis.  The  instrument
provided for the automatic introduction of a 40-microliter sample into a
reaction chamber where a nitrogen carrier gas transported the reaction
product to an infrared detection system to measure total carbon.  The timer
mechanism of the total carbon instrument was connected to the sampling sys-
tem switching unit to assure sample analysis synchronization.  Total  in-
organic carbon values were determined only on an interim manual basis by
injecting wastewater samples in an acid media through which the carrier
gas by-passed the reaction chamber and went directly to the infrared
detection section.

Two additional automated wet chemistry systems were utilized in the pro-
ject laboratory for the determination of total Phosphorus and total
Kjeldahl nitrogen.  Although throughout most of the study these partic-
ular systems were operated on a manual sample introduction basis, they were
coupled to the automatic sampling system in the last portion of the pro-
ject.  The two autoanalyzers included a total phosphorus system using the
Industrial Technicon  Method  4-68W operated at a low range of 0 to 40  mg/L
phosphorus, and a total Kjeldehl system using Technicon Industrial Method
30-69 adapted for measuring a low concentration of 0 to 60 mg/L nitrogen.
The systems were adapted to use a common sample input and a single con-
tinuous helical digester operated at a temperature of 400°C.  The output
stream was separated for respective simultaneous determinations,  and  re-
sults were indicated on a two-pen recorder.

The mode of operation of the continuous automatic sampling and analysis
system was on the basis of four days a week (from 10 a.m. Monday  morning
continuous through 10 a.m. Friday morning).  This period of operation was
selected due to manpower constraints for system maintenance and data  tab-
ulation of chart outputs.   During the first eighteen weeks of research
study, the sampling system was operated on all eleven sampling points; how-
ever, sample introduction to the Technicon and Union Carbide analytical
systems was done on a manual basis after certain sample preparation measures
had been performed.  During the final ten weeks of the study, the sampling
points (including the common primary effluent point and the two secondary/
final effluent sampling points) .  With the reduced levels of suspended

                               146

-------
solids, the Technicon and Union Carbide  systems were  operated  on  an  auto-
matic basis in conjunction with the other instrumentation  and  sample col-
lection activities.  At the end of the study,  the  sampling analytical
system was operated on a continuous basis for  the  last  20  consecutive
days of the study.  In this manner, various modes  of  operation of the
sample monitoring system were used during the  study.  The  system  is
pictured in Figures B-3, B-4, and B-5.

                            Discussion

One of the initial problems with this monitoring system was the operation
of the sample point pumps.  Troubles were experienced with the six sample
points located in the activated sludge aeration tanks because  they had  a
tendency to pump air, thereby displacing the necessary  liquid  stream for
the sampling system.  This difficulty was corrected by  attaching  an  appro-
ximate one-foot diameter screen deflecting device  around the inlet area
of each of the submersible pumps.  Since the pumps were operated  on  a
continuous basis, some plugging was experienced of the  coarse  screens
around the pump inlets or in the "Y" strainers just before the switch-
ing collector device due to solids buildup.  This  condition was partic-
ularly true of the return sludge sample  pumps  in that over an  eight- to
ten-hour period there would be enough plugging to  terminate sample flow.
Because these sample points were located so close  to  the central  switch-
ing system, requiring approximately one  minute from the time the  pump
started until flow reached the switching device, the  operation of these
two return sludge sample point pumps was changed from continuous  opera-
tion to operation only when the TAFI switching system actuated the
solenoid valve associated with each of the sampling points.  Even with
these preventative measures, sample system plugging was a  continuing
problem.  Therefore, in addition to the  normal weekly flushing measures
that were performed, all pumps and strainers were  checked  on a daily
basis, and if necessary, cleaned to assure continuous representative
sampling.

Another problem area was that of removing solids in the sample stream
to eliminate sample carryover and achieve feasible operation of the
Technicon and Union Carbide analytical systems.  The  first solution
considered was the use of a Technicon continuous filter system which
proved to be very ineffective on the return sludge stream  and  effective
only at a very low flow rate for the mixed liquor  sample stream.   Various
in-line filters and settling systems were applied  to  this  problem in an
attempt to find a solution.  However, all of these approaches  proved in-
effective either due to high rates of plugging or  inability to eliminate
carry-over during the comparatively short (5 to 10 minute) sample cycle.
Various in-line filters and settling systems were  applied  to this problem
in an attempt to find a solution.  The alternative centrifugal solid
separation using a Dorr-Clone cyclone system was also attempted.   This
alternative was also found to be unsuccessful  due  to  the nature of the
biological solids.  The eventually adopted solids  removal  procedure,

                                147

-------
when all eleven sampling points were being sampled, involved  the quiescent
settling in the refrigerated sample collector tubes for a period of  6  to
16 hours and then manual introduction of the supernatant into  the Technicon
and Union Carbide analytical systems.  Even though the sample  collection
tubes were previously cooled prior to receiving the sample, analytical re-
sults indicated that some soluble nitrate, COD and ammonia alterations took
place during this residence time in the sample collector.  This situation
was corrected by the installation of Whatman No. 4 filter papers in  the
top of each of the collector test tubes, which provided a gross solids re-
moval prior to the settling period.  Results from these prefiltered  samples
compared favorable with appropriately collected grab samples  that were treat-
ed by immediate centrifugation and filtration.  Therefore, the reason  for
the mode of operation previously described for the first 18 weeks, during
which all 11 points were sampled, was the need to provide a feasible ap-
proach for solids removal from samples having such a wide range of bio-
logical solid concentrations.  When only the overall inlet samples of
the activated sludge system were collected by the system (Sample Points No.
1, 2, and 3), the Technicon and Union Carbide analyzers accepted the sample
streams directly.  This was achieved because the highest concentration of
suspended solids was approximately 150 mg/L, as opposed to the 2,000 and
around 8,000 mg/L ranges found in the mixed liquor and return  sludge,  respec-
tively.  Therefore, on a three sample point basis, continuous  automatic
monitoring using all analytical systems was accomplished during the  last
ten weeks of this study.

Some indication of the type of data output of the continuous  sampling
monitoring system is presented in Figures B-6 through B-12 which show
sample charts from each of the different recorders used in the system.
As indicated by the ortho-phosphate and ammonia nitrogen output curves
in Figure B-6, the normal cycle for complete automatic monitoring con-
sisted of a one-hour cycle broken up into ten-minute segments.  For
example, the first ten-minute segment is a sample of the secondary ef-
fluent from activated sludge system No. 1, followed by secondary ef-
fluent from system No. 2, then a sample of the common primary  effluent
entering the pure activated sludge system.  The remaining segments consist
of a repeat of the same sample, followed by a standard and then a water
wash, and a repetition of the cycle.  The normal analytical standard,  as
indicated on this graph consisted of 20 mg/L ortho-phosphate  and 20
mg/L ammonia nitrogen.  The high removal of phosphorus is quite obvious
by the output result and the consistency between the two samples of  the
identical primary effluent which also indicates the precision  of the
system.

Figure B-7 shows a typical cycle from the COD and combined nitrate-
nitrite-nitrogen output system.  The standard used during the  cycle
depicted consisted of 1 mg/L of nitrate nitrogen and 250 mg/L  of COD
using primary standard phthalic acid as the carbon source.  The tap
water is shown to contain significant nitrate and little or no COD.
                                148

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Figure B-8 presents the Union Carbide total carbon analyzer results  for
a typical monitoring cycle.  Also, included are a typical analytical
standard curve and a calibration curve.  Although the  total phosphorus
and total Kjeldahl system was not normally operated with the  continuous
automatic monitoring system, Figure B-9 presents an one-hour  automatic
cycle showing the same order of samples and standard as presented in
previous figures.  It can be noted in Figure B-9 that  there was consid-
erably less phosphorus removal than in Figure B-3, because of the type
of investigation being conducted at the time of the sampling.

The analytical monitoring results of the other instruments, included
those from the dissolved oxygen analyzer, turbidity meter, and pH sens-
ing unit.  These results were essentially unchanged throughout the sur-
vey and were not altered by the mode of operation.  Figure B-7 presents
typical output of the dissolved oxygen monitoring system and  shows that
a sharp peak D.O. occurring at the center of the aeration tanks can be
followed through the system by adding the approximate  detention times in
the respective units.  The recorder response for sample probes placed in
the aeration tank showed more variability than those in the final clari-
fier; however, they were still very adequate for assessing current dis-
solved oxygen values.

The typical turbidity output for both operation of the system with 11
points and operation of the system with 3 sampling points are indicated
in Figure B-ll.  Under operation of all 11 points, the response was most
obvious on the turbidity output when the number 10 return sludge pump
became plugged.  While monitoring the three sampling points only, the
occurrence of a discharge of high solids coming into the activated sludge
is similarly quite obvious.  The principal uses of the turbidity output
were for approximate sensing of the changes in suspended solids in the
process and also for indicating adequate operation of  the sample pump-
ing system.  Figure 12 presents some sample output of  the pH  recording
system.  The high pH of the tap water rinse system is  most obvious,
particularly in the 3-point cycle as opposed to the 11 sampling point
operation.

The value of having monitoring systems on a continuous basis with im-
mediate assessment of phosphorus, nitrogen, COD and carbon removals, is
the ability to provide current knowledge for precise control  of plant
operation.  An example of these changes is shown in the results of a
study to assess the effect of dissolved oxygen level on the phosphorus
removal ability of the plant.  The results for one short period of time
are presented in Figure B-13 and show distinct periods of phosphorus
release and phosphorus recovery in the test system, while the control
system continued to remove a high degree of phosphorus.  Having an
operable monitoring system for use in control of the plant has created
a high appreciation for immediate assessment of a critical parameter,
whether it be phosphorus, nitrogen, or carbon in the optimum  operation
of any wastewater treatment facility.
                               149

-------
The monitoring system as installed in Baltimore, was very experimental
in nature and design, and, with respect to maintenance, did not compare
to a ruggedly designed industrial monitoring system.  The marginal pump-
ing capacity of the sample point pumps, the flow restrictions caused by
the small solenoid valves used in the switching system and the solids
removal problem would be significantly improved upon with the experience
gained in the monitoring operation for this project.  The Technicon Auto-
analyzer systems as installed are more oriented for intermittent labora-
tory use as opposed to the continuous service demanded in this study.

The maintenance time was quite low on the ortho-phosphate, ammonia
nitrogen and total carbon analyzing systems.  Maintenance was the high-
est on the Auto-analyzer systems, involving digestion that included the
COD, total phosphorus and total Kjeldahl nitrogen systems.  However, one
of the more tedious aspects of this project was the data translation re-
quirements.  For example, creating a total of approximately three miles
of chart paper and having to go manually through this output to make the
analog peak to digital tabulated data transfer, was exceedingly time con-
suming and occupied considerable manpower.  The value of having the data
output in a digital printout form directly at the time the analysis was
performed is fully appreciated as essential, if there are manpower limita-
tions and if it is desirous to go back and recover the data.  Therefore, such
devices should be given serious consideration when installing a permanent
monitoring system.  Regardless of a data recovery ability, the opportunity
of immediately assessing plant performance rather than having to wait five
days for BOD results or a half-day for other analyses is a very great
asset in optimizing the performance of a biological wastewater treatment
plant.

                      Monitoring Conclusions

1.   A continuous automatic monitoring and sampling system has been pre-
     sented and six months of operation has verified the feasibility of
     such a system.

2.   Although most Technicon Auto-analyzer systems require more develop-
     ment before being applied as low maintenance, stable, rugged indus-
     trial monitoring systems, Auto-analyzers for ortho-phosphate and
     ammonia nitrogen, indicated that they would be effective as long-
     term monitors.

3.   The total carbon analyzer system utilized as a part of the sampling
     monitoring analytical capability demonstrated reasonable application
     to waste treatment plant monitoring.

4.   Dissolved oxygen, pH, and turbidity monitoring devices are at satis-
     factory levels of development for immediate use in activated sludge
     treatment plant monitoring systems.
                               150

-------
The value of immediate assessment of the critical operating
parameters is important for maintaining optimum performance
of a wastewater treatment plant and for making meaningful
operational changes for variations in inlet wastewater con-
centrations .
                          151

-------
                                             FIGURE  B.I
                               PHYSICAL LOCATION OF SAMPLING POINTS
I
u!
       0   25   50   75  100
           SCALE IN FEET
       PRIMARY
       EFFLUENT  I
                           AERATION TANK
NO. 2  TEST     «—
                           AERATION TANK
                                NO. 1  CONTROL —»•
                                                       CONTROL BUILDING
                                                                 —ANALYTICAL LABORATORY
                                                          INLET
                                                                                SETTLING TANKS
                                                                           NO. 2              NO. 1
                          PROCESS DIAGRAM LOCATION  OF SAMPLING POINTS
                                                  (NOT TO SCALE)
                       CONTROL
                                                                                 (T)
                                                                                 V
                                                                                 A
                                                  CLARIFIED
                                                  FINAL EFFLUENT
                                                                  RETURN SLUDGE

-------
                                                                                 FIGURE   B-2

                                                     FLOW  DIAGRAM  OF  COMPLETE  SAMPLING AND  ANALYTICAL  SYSTEM
    SAMPLE  POINT PUMPING AND PIPING       FLUSHING, STRAINING AND  OVERFLOWING        SWITCHING AND  SAMPLE COLLECTION
                                                                                                                            ANALYTICAL SYSTEMS
                                                                   CONSTANT
                                                                   HEAD OVERFLOW
o»
                                         FLUSHING
                                         VALVE-7     STRAINER
                                                                                                   REFRIGERATED
                                                                                                   SAMPLE  COLLECTOR
J IITNO PHOSPHATE
                                                                                                                                                     HH6MIA MITKQtEII
                                                                                                                                                     MITRATE + NITRITE
                                                                                                                                                     CHEMICAL amtll  BEMAM
                                                                                                                                                      OTAL »»HN
                                                                                                                                                     TOTAL PHOSPNORUS
                                                                                                                                                 X^l  TOTAL K1ELPAHL NITROGEN    I

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     B-3
Figure i Aeration Tank Sampling Point
FigureXSample Switching and Collection System
                                Figure/Automatic Analyzer Systems

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  S-Of **, «*••*/

-
              V_ WiMAtr ^
                             :
          FIGURE
          FIGURE
          FIGURE A

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FIGURE
FIGURE

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   • •*•••••»•»*••••»•
  3/S-**/" 7Z*4,f,rr &w* { 3 sr»r*~* **P**S+>< ) (?
FIGURE
FIGURE

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CD
 I
                                     FIGURE B-13

            PHOSPHATE REMOVAL IN FULL-SCALE  ACTIVATED SLUDGE

                            WITHOUT CHEMICAL ADDITION
    O
GO


§
Q-


o
x
t—
0£

O
          TEST SECONDARY

          EFFLUENT
          COMMON PRIMARY

          EFFLUENT
          CONTROL

          SECONDARY

          EFFLUENT
          o X 0X0° x°«X0XoM»X°Xo
        0
               11/11/69
11/12/69
                                            11/13/69
11/14/69
                                     TIME - HOURLY SAMPLES

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1
Accession Number
w
5
,y Subject Field & Group
05D
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
Organization
        City of Baltimore, Maryland   (Subcontracted by Roy F. Weston,  Inc.)
    Title
        PHOSPHATE STUDY AT THE  BALTIMORE BACK RIVER WASTEWATER TREATMENT PLANT
 10
Authors)
        Mil bury, William
                                 16
                                    Project Designation
                                            FWQA Project 17010 DFV
                                     21
                                         Note
 22
     Citation
        Contract report, 158  pages,  16 tables, 33 figures
 23
Descriptors (Starred First)

   *Biological  Treatment, *Water  Pollution  Control, *Process Control,
     Phosphorus, Analyses, Instrumentation
 25
     Identifiers (Starred First)
        *Municipal Treatment,  Operational Parameters, Process Monitoring
 27
     Abstract
      Two parallel 10 mgd  activated sludge systems were used  in  a  six-month study to
      evaluate the effects of operating conditions and design  parameters on the
      previously observed  high degree of phosphorus removal at the Baltimore facility.

      Phosphorus removal in the control system averaged 82  percent which is in sharp
      contrast to the 15 to 20 percent phosphorus removal typical  of activated sludge
      systems.

      The reaction mechanism of phosphorus removal at Baltimore  was not clearly
      demonstrated.
Abstractor  £_  p>
                               Institution
                                   EPA,  FWQA, AWTRL, Cincinnati, Ohio
 WR:102 (REV. JULY 1969)
 WRSIC
                         SEND, WITH COPY OF DOCUMENT. TO: WATER RESOURCES SCIENTIFIC INFORMATION CENTE^	
                                                   U.S. DEPARTMENT OF THE INTERIOR
                                                   WASHINGTON, D. C. 20240


                                                                            * GPO: 1970-389-930

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