PROCEDURES FOR EVALUATING

PERFORMANCE OF WASTEWATER TREATMENT PLANTS

A Manual
Prepared for


Environmental Protection Agency
Office of Water Programs
Washington, B.C.

Under Contract No.  68-01-0107
by

URS RESEARCH COMPANY
Environmental Systems Division
San Mateo, California 94402

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ABSTRACT
This manual establishes a procedure for the
evaluation of the performance of wastewater
treatment plants.  It furnishes the informa-
tion necessary to identify and classify vari-
ous types of treatment plants.  This manual
details the processes commonly utilized in
wastewater treatment.  The common problems
affecting plant operation are identified and
described.  The description first states the
problem and then identifies the indicators
of the problem, which are listed in order of
their relative importance.  The type of lab-
oratory tests which should be performed are
listed, along with other evaluation tech-
niques.  Finally, operational, maintenance,
or other corrective measures are listed in
order of their effectiveness.

References are given for an in depth review
of unit and process operation and for addi-
tional information (where applicable).   A
glossary is also included.
                     iii

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                                  CONTENTS

Section                                                               Page

           INTRODUCTION                                                  1
    I      PLANT EVALUATION PROCEDURES                                   3
           Preparation for Site Visit                                    5
           On-Site Inspection                                            7
           Procedures for Problem Evaluation                             9
           Total Plant Evaluation                                       10
   II      WASTEWATER TREATMENT SYSTEMS OPERATIONAL DATA                17
           Pretreatment and Primary Treatment Data                      19
           Secondary Treatment Data                                     21
           Secondary Treatment Data - Activated Sludge Process          23
           Advanced Waste Treatment Data                                25
           Solids Treatment Data                                        27
           Common Solids Treatment Data                                 29
  III      SAMPLING AND TESTING
           Introduction                                                 31
           General                                                      31
           The Sampling Program                                         32
   IV      COMMON OPERATING PROBLEMS AND SUGGESTED SOLUTIONS
           Introduction                                                 41
           Pretreatment                                                 49
           Primary Treatment                                            59
           Secondary Treatment                                          64
           Advanced Treatment                                           82
           Disinfection                                                 89
           Metering                                                    109
           Solids Handling                                             111
                                     IV

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Appendix                                                              Page
   A      CLASSIFICATION OF WASTEWATER TREATMENT PLANTS                A-l
          Classification by Function                                   A-l
          Operator Classification                                      A-2
          Location of Temperature Zones in the United States           A-3
          Common Processes and Operational Units                       A-4
   B      PERSONNEL REQUIREMENTS                                       B-l
          General Skills                                               B-l
          Manpower and Work Scheduling                                 B-2
   C      PRIMARY TREATMENT MODE (Background Information)              C-l
          General                                                      C-l
          Pretreatment                                                 C-3
          Chemical Precipitation                                       C-10
          Chlorination                                                 C-10
   D      SECONDARY TREATMENT                                          D-l
          General Background of a Biological Reactor                   D-3
          Trickling Filters                                            D-4
          Activated Sludge                                             D-6
          Stabilization Ponds and Lagoons                              D-8
          Intermittent Sand Filters                                    D-9
          Secondary Clarification                                      D-10
          Package Aeration Plants                                      D-ll
   E      ADVANCED WASTEWATER TREATMENT                                E-l
          General Background                                           E-l
          Chemical/Physical Treatment                                  E-2
          Carbon Adsorption                                            E-3
          Ammonia Stripping                                            E-4
          Electrodialysis                                              E-5
          Reverse Osmosis                                              E-6

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Appendix                                                                Page
   F       SOLIDS TREATMENT AND DISPOSAL                                 F-l
           General Background                                            F-l
           Treatment of Sludge                                           F-2
           Sludge Thickening                                             F-3
           Sludge Conditioning                                           F-4
           Sludge Dewatering                                             F-5
           Disposal of Sludge                                            F-6
   G       CONTROL AND METERING SYSTEMS                                  G-l
           Control Systems                                               G-l
           Flow Measurement                                              G-2
   H       MAINTENANCE DATA SYSTEM                                       H-l
   J       REFERENCES                                                    J-l
   K       GLOSSARY                                                      K-l
                                    VI

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INTRODUCTION

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INTRODUCTION

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                               INTRODUCTION
     The purpose of this manual is to provide technical guidance for persons
conducting evaluations of wastewater treatment plants and serve as a model
which can be used by state regulatory  agencies.

     It furnishes the information needed to facilitate identification and
classification of various types of treatment plants.  It also details
the processes commonly utilized in wastewater treatment.  The common prob-
lems affecting plant operation are identified and described1.  Several
aspects of each problem are covered: exactly what is the problem; how it
is detected, what are the possible causes, and what solutions are feasible.

     It is assumed that the manual user has a general familiarity with both
typical wastewater treatment plant design and operation, as well as a tech-
nical background in sanitary engineering.  In addition,  the user should
complete a training program which includes the evaluation of a series
of wastewater treatment plants using this manual and other evaluation methods.

     As wastewater treatment technology is changing rapidly, this manual
will be reviewed and updated routinely in order to maintain its effective-
ness as a plant evaluation tool.
MANUAL FORMAT

     In order for the manual to be an effective tool in the evaluation of
wastewater treatment plants, familiarization with its structure as well
as its advantages and limitations is necessary.

     Like any other tool which is being used for a particular purpose,  the
manual can be utilized best by familiarization with:

          •  TABLE OF CONTENTS - so material can be quickly and
             easily located,

          •  GLOSSARY - to understand the manual terminology.

          •  PLANT OPERATIONAL DATA - to become familiar with
             operational parameters,  loading rates,  and support
             systems used with each unit operation.

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          •  PLANT CLASSIFICATIONS - to give background information
             on the schemes,  their processes,  and their relation to
             a treatment system.

          •  PLANT EVALUATION PROCEDURES - to become familiar with the
             steps required in performing a plant evaluation.

          •  DATA FOR EVALUATION - an in-depth review of the data
             required in conducting a plant evaluation.

     This manual contains four principal sections and several supplemental
appendixes:

     SECTION I     Procedures for Plant Evaluation.   This section of
                   the manual contains a step-by-step procedure for
                   organizing information before the plant is visited
                   and for performing the on-site evaluation.

     SECTION II    Wastewater Treatment Systems Operational Data.  This
                   section of the manual contains data on the common
                   operating parameters,  loading rates, waste products
                   accumulated from process operation,  and the support
                   systems which are used in the various unit operations
                   and processes.
     SECTION III
Sampling and Testing.   This section of the manual
contains information on the type of sampling to be
done, location of sampling points, and analyses to be
performed for the particular treatment system.
     SECTION IV    Common Operating Problems and Suggested Solutions.
                   This section of the manual is to properly identify
                   problems which frequently occur in wastewater treat-
                   ment plants and delineate which corrective measures
                   should be implemented.

     APPENDIX A    These appendixes supply the background information
      through      on the various treatment systems;  how they are
     APPENDIX G    classified,  personnel  requirements,  maintenance
                   data programs,  and information on the various unit
                   operations.

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PROCEDURES

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I
PLANT  EVALUATION
PROCEDURES

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                                 Section I
                      PLANT EVALUATION PROCEDURES
     The evaluation of a wastewater treatment plant consists of an
in-depth analysis of the following basic elements:

          •  Plant performance
          •  Operational problems

          •  Operating personnel
          •  Sampling and testing program

          •  Laboratory facilities
          •  Maintenance data program.

     Information and data for each element are gathered and analyzed in
four interrelated phases,  namely

          1.  Preparation for site visit
          2.  On-site inspection

          3.  Problem identification
          4.  Total plant evaluation.

     The estimated evaluation time will depend on the size and complexity
of the plant,  the amount of preparation on the part of the investigator(s),
and the willingness of the plant personnel to cooperate with the
investigator(s).

     For planning purposes the following table gives values which can be
used for the initial evaluation.  The estimate of the times required to
perform a treatment plant evaluation will vary with the complexity of the
treatment facility and other factors; this variation could be as great
as 50 percent.

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           TREATMENT PLANT EVALUATION PERIOD
                          (days)
Preliminary Preparation
On-Site Investigation
• Visual Inspection
• Record Analysis
• Problem Evaluation
and Solution
Written Report

1
1/4

1/4
1
1
1/2
Plant Size (MGD)
10
i ii

1/2 1
2i 2i
0 to 3 0
1

100
to Z\

to l£
to 4
to 4
1
Total Days (maximum)
13

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PREPARATION FOR SITE VISIT

     Preparation for the on-site inspection should include compilation
and review of information which provides a description of the plant's
physical setting,  plant design details, plant operating personnel, and any
available performance records, previous inspection reports, compliance
orders,  etc.  Reference material relevant to the type of plant being evalu-
ated should also be reviewed  (see Section II and the Appendixes).

     The following are specific steps suggested for use in preparation for
the on-site visit:

1.  Compile and Review Information on Plant's Physical Setting

     Information describing the physical location of the plant will be
required in the evaluation.  The information should include the following:

     (a)  Classification of Treatment System

          •  Type of plant (see Appendix A)

          •  Contributory population (domestic, industrial, etc.)
          •  Wastewater system (sanitary, combined, etc.)
          •  Geographic-climatic effects (see Appendix A) to
             determine if extreme geographic-climatic areas could
             have an effect on plant performance.  This should
             include both extremes of temperature and precipitation
          •  Determine, if possible, the characteristics of the
             plant's influent and effluent.  This should include
             both values of the parameters measured by the plant
             (BOD5,  pH, COD, temperature, etc.), and flow quantity and
             variations with time;

     (b)  Identification of Discharge Requirements

          For a particular plant location,  this might consist of
          allowable COD,  pH,  BODg, etc., or any special controlling
          conditions such as a minimum DO and chlorine residuals.  If
          the official data are not readily available from the plant,
          then try contacting local and/or state health departments
          and state,  regional, and municipal pollutional control
          agencies.   These agencies may be able to supply the needed
          information.  These data should then be compared to the
          matrix,  Table A-2 of Appendix A,  which contains expected
          effluent  quality criteria for various treatment systems.

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2.  Compile and Review Information Describing the Plant and Staff

     This should be accomplished in advance of the plant visit, recognizing
that most state agencies will have some sort of records and previous
evaluations which can be used as a comparison between the past, existing,
and optimum operation of the plant.  The information required to make this
comparison includes:

          •  Size of plant (design, average daily flows, peak flows)

          •  Type of unit operations
          •  Historical operating data

          •  Size of staff,  their qualifications, and distri-
             butions of time spent between unit operations

          •  Review all relevant plant documents such as design
             drawings, operating manuals for various pieces of major
             equipment, and summary (or monthly) operating reports.

This information should be compared with sections of the manual or other
sources which give information on the following:

          •  Wastewater treatment systems operational data (use
             design specifications, where available, or see Section II
             of this manual)

          •  Personnel requirements (see Appendix B)

          •  Classification of wastewater treatment plants
             (see Appendix A).

3.  Prepare a Pre-Vigit Evaluation Data Sheet

     Data will be needed prior to the evaluation to insure adequate data-
gathering at the time of the on-site visit.  The pre-visit evaluation guide
should include a summary of all background information.

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ON-SITE INSPECTION

     The inspection of the plant should be accomplished in several phases
with each phase being progressively more detailed.  The visit(s) would
typically consist of two phases:

     Phase One—a general orientation and overview of the plant and
     its operation,  including:

          •  Meet initially with plant engineer or chief operator.  Have
             him describe the plant and its principal operating charac-
             teristics, on a schematic basis (this and the following
             steps are to help orient you to the plant,  but also to
             give you an indication of how well the staff understands
             the system).

          •  Interview plant staff members, starting with plant super-
             intendent and other supervisory personnel and working
             progressively through the appropriate operating personnel.

          •  Determine routine plant performance and compare this with
             design performance and norms section of the manual (see
             matrix. Table A-2, Appendix A).

     Phase Two—problem identification with an evaluation as to effect
     on overall plant performance.  This phase also includes the pro-
     cedure for laboratory evaluation.

     Problem identification begins with a tour of the facility.  Have the
plant engineer or operator give you a complete tour of the facilities.
Watch for and inquire about:

          •  Excessive particles and/or floe flowing over overflow weirs

          •  Excessive grease and scum buildup

          •  Any unusual equipment such as special pumps,  chemical
             feeders, temporary construction on structures or other
             jury-rigged  systems which are being used to correct
             problems (or possibly causing them)
          •  Evidence of flow in by-pass channel to parallel units
             because problems have come up in normal operating units
  Always  contact  the  plant  manager  in  advance  to  set  up  an  appointment;
  avoid ill-will  from arriving  unannounced.

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            •   Excessive  odors
                              \
            •   Abnormal color of wastewater in various  process  stages.
       If  any  special  plant modifications were made, determine:
            •   Purpose
            •   Physical makeup
            •   Effect  on  the other treatment processes  by comparing
               old  operational data with data after modification.
REVIEW RECORDS
In general, all records should be analyzed and compared with the
information in the manual and/or other sources for consistency,
method of calculation and to verify that recorded values are within
the range recommended by this manual or other sources.
The following records should be reviewed:
       FLOW.   Hydraulic' data are reviewed for:
        •  Consistency with the design flow and  with present
            population served
        •  Over- and  under-loading of  the various treatment units.
        •  Meter calibration
       UNIT OPERATIONAL DATA  (BOD, COD,  Suspended Solids,  etc.)  are
       reviewed for:
        •  Consistency with design specification and values indicated
            in the  manual or other sources
        •  Extreme values for the daily flows.
       POWER CONSUMPTION  records should be reviewed for values  above or
       below normal.   These records would tend to indicate the  following:
        •  Operating  heads lower than  the pump's rating
        •  Specific gravity or viscosity of liquids being pumped
            is too  high.
       POWER CONSUMPTION  AND FLOW RECORDS.  Analyses of the FLOW data in
       combination  with POWER might  indicate the  following:
        •  Output  of  each pump separately and pumps collectively
        •  Unusual operating conditions which are in effect or have occurred
        •  Changes in efficiency of  pumps by  comparison of gallons  pumped/
            kilowatt hour over an extended period of time.

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                     *
     MAINTENANCE DATA .  The maintenance program is usually a good indi-
     cator of operational quality; this can be indicated by checking:

       •  Manufacturer's maintenance schedule for components

       •  Type of routine being used for maintenance scheduling (as
          compared with Appendix H)

       •  Personnel qualifications for the type of maintenance work
          being performed.

PROCEDURES FOR PROBLEM EVALUATION

     In general, the problems detailed in the manual are those most
commonly encountered.  However, these procedures can be used for any type
of problem evaluation.  The first step in problem evaluation is to deter-
mine if the plant is meeting design performance standards by comparing
its effluent quality and overall removal efficiencies with those specified
by the design (if design specifications are not available, compare the
plant's performance against the guidelines given, see Appendix A).  If the
plant does not routinely meet performance specifications, it will be neces-
sary to determine whether the deficiency is due to problems wiiich fall
into two categories:

     PROBLEM DEFINED—If the treatment plant operator has defined
     the problem:

          a.  Verify general area of problems, such as related to
              process, maintenance or design, sampling, etc.

          b.  For common process problems, refer to that section of
              the manual dealing with the problem (see Section IV).

          c.  Develop sampling and testing program to provide
              additional data, if needed  (see Section III).

     PROBLEM UNSPECIFIED—If effluent discharge does not meet required
     standards and no definite problem area has been established:

          a.  Review flow and process records again in greater detail.

          b.  Recheck sampling and testing procedures required (see
              Section III).

          c.  Compare sampling and testing program against recom-
              mended programs in the manual.

          d.  Recommend a modified testing and sampling program to
              furnish additional data for evaluation (see Section III).
*  Refer to 0 & M manual requirements.

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          e.  Compare the data with the problem indicators detailed
              in the manual (see Section IV) to see if there is a
              solution offered.
          f.  For those problems not specifically covered in the manual,
              and if the evaluator's experience does not suffice,
              should be recommended that a consultant be hired.
     MAINTENANCE PROBLEM—Refer to sample maintenance program  (see
     Appendix H) and compare with actual plant program; recommend new
     program where needed.
TOTAL PLANT EVALUATION
     This should include the following:
     1.  TOTAL EVALUATION OF PLANT—utilizing the Evaluation Guide
         materials at the end of this section
         (a) Modification of initial evaluation, if appropriate
         (b) Differences in existing plant performance and operational
             data with design and/or manual operational or performance
             data
                                                    *
         (c) Personnel needed for adequate operation
         (d) Type of sampling program required to give needed data
         (e) Maintenance system needed
         (f) Laboratory equipment needed
         (g) Problems encountered
             •  Those corrected by visit
             •  Those that need outside help to correct
             •  Proposed solutions.
     2.  FINAL REPORT—should contain the following elements:
         (a) Summary of on-site visit
         (b) A list of problems encountered
         (c> Solutions recommended
         (d) Proposed action.
* See EPA Staffing Guides.
                                     10

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                        Pre-Visit Evaluation Guide
Plant Identification (Name, Owner, etc.)
Plant Location,	
Operator in Charge.
Date of Evaluation.
Evaluation by	
Date of Plant Construction
Name of Design Firm.
Regulatory Agency of Concern
Stage Operating Permit?
                        obtain prior to visit
                         ow Route to- Unit
                        bpulation
          Type  of  Wast
                Combi
                Sanit
          Geographi
                          tic  Effects
                                    o
                            Ranges ( F)
                Rainfall Extremes (in.)
Background Informati
     1.  Type of  Pla|
     2.  Schematic  o
     3.  Contributor
                Domest
                Indust
                Other
                                      11

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6. Plant Wastewater Characteristics
                         Nitro-
                         gen
                             Total
                             Phos-
                             phorus
                             (mg/£)
 Sus-
pended
Solids
COD
Flow
(MGD)
Dis-
solved
Oxygen
a.

b.
    Plant influent
Plant effluent
    Overall perform-
    ance (%)
    Design and/or
    manual recommended
    performance
    values (%)
    Existing
    receiving water
    quality
    Required
    receiving water
    quality
7.  Possible Problems
         a. Identified from|qtfM£ting reports
         b.Identified fron/previous inspection reports
         c. Complaints
                                     12

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                         On-Site Evaluation Guide
1.   Flow
     Design (actual).
     Daily Average	
     Peak 	
   Note any variation or erratic flow patterns.
2.  Process Units Employed and All Pertinent  Information
 Unit
Process
                    Operational Parameters
Existing
 Plant
Values
Design and/or
 Recommended
Manual Values
                                         Loading Rates
Design and/or
 Recommended
Manual Values
3.  Historical Operational Data
            Organize qata to see if following occurred:
              Equipment failure - when, what type failure, how  long out
              of service

              Extreme weather conditions

            Exdessive loadings on plant:
              Flow — when, how long, results of

              Organic - when, how long, results of
                                     13

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         •  Changes in process operation, such as:

              Increasing air flow to activated sludge units

              Decreases in detention times

              What caused changes? Are changes still in effect?  Why?
4.  Plant Personnel
     Size of Staff for Daily
      Average Flow Handled
                       Qualifications
                           Types of Shifts
                               (hours)
 Existing
   Plant
Recommended Manual
     and/or
  'Other Sources
 Existing
Personnel
 Recommended
Manual and/or
Other Sources
Exist-
 ing
Recom-
mended
Manual
5.  Laboratory Evaluati
Type of 1
TreatmenJ
Type

nests Perfo
, System Ev
Frequency

nnedl for
aluajbed
Location

Testing Procedures
and Equipment Used

Type of Tests Performed ;
for Treatment System
as per Manual <

                                     14

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                       Guide for Overall Evaluation
                                                                  Yes
                                                                        No
I.   OPERATING PROBLEMS
            Are there problems affecting the
            performance of this plant?
            Can they be solved without major construction?
            Are the skills to solve the problem available
            among the staff?
            Was a solution suggested by the evalua
            Is it a permanent solution?
II.
     THE SAMPLING AND NESTING PROGRAM
         •  Are the sanil ing locations suitab
            Are testin
            Is testing
            process co
                        requency adequ
                        rol?
                                    Stand
III.   LABORATORY FACILI
            Is the labofa\ory
            apparently
                                    rgahized and
                                    s intended?
            Is there ertough VqUpnJfent to perform
            all the nelessar
            Is the equipment being properly used?
IV.
     PERSONNEL - Planf Ojfera/cors (including lab personnel)
            Is the stfe^fxraequate in size?
            Are theyfqualif ied?   State certified?
            Is there! an operator training program?
            Are the/ shifts adequate and balanced?
                                     15

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Evaluation Guide - page 2
V.  OVERALL PLANT PERFORMANCE
            Is it operating to its design
            specifications?
            Is it meeting discharge requirements
            for its location?
            Even if adequate, can plant perfoi
            be improved by simple and/or inexper
            changes?
                                                                   Yes
                                                            No
Evaluator:
         2.

         3.
If any of
taken:
                        e answers are
                       ollowing steps should be
 Discuss
 plant s
 In coop
 officials.
            visit
        ms encountered
        tended
   ction.
   commendations with treatment
ion with the plant operator (and local
if necessary),  decide on a course of
             action lo solve the problem(s).
             After
             plant
         suitable period of time, revisit the
        b make a re-evaluation.
                                     16

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OPERATIONAL DATA

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II

WASTEWATER
TREATMENT  SYSTEMS
OPERATIONAL  DATA

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                                 Section II
           WASTEWATER TREATMENT SYSTEMS OPERATIONAL DATA
     This section of the manual contains data on the common operating
parameters,  loading rates,  waste products accumulated from process opera-
tion,  and the support systems which are used in the various unit operations
and processes.

     Once the plant has been classified and the type of unit operations
and processes have been determined, the information in this section will
serve as a guide to evaluation of the overall plant operation.   If operating
and performance data are largely different,  investigation of plant processes
should be made to determine if the problem is with equipment or process
failure.  These should be noted, and if remedial solutions can  be deter-
mined by use of this manual (Problem-Solution Section IV,  this  manual),
they should be suggested to the plant operator.  Where problems are beyond
the scope of this manual,  or experience of the evaluator,  it should be
suggested that the operator take the necessary steps to get proper outside
help.

     In the total evaluation of the plant, a list of problems encountered
should be made and the steps that are being taken or were suggested to cor-
rect them.  A return visit should be made after the operator has had suf-
ficient time to correct the problems and a new evaluation made.
                                    17/18

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OPERATIONAL DATA ON PRETREATMENT AND
  PRIMARY TREATMENT OF WASTEWATER

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                                              Table  II-l
                         PRETREATMENT  AND PRIMARY  TREATMENT DATA
Unit Operations
or Process
Racks
o coarse
o medium
o fine
o mechanically cleaned
Grit Chambers
o Air injected






Cutters-Shredders
( comminuters)


Pre-Aerat ion




Sedimentation
Primary sedimentation
before activated sludge
Inhoff tanks
Primary sedimentation
tanks before trickling
filters
Intermediate sedimentation
between multistage
trickling filters
Final sedimentation after
activated sludge
Final sedimentation after
standard trickling
filters
Final sedimentation after
high-rate trickling
filters
Operational
Parameters
Loading Rates
2 /
Bar Spacing in Inches—
1-2
1/2 - 1
1/32 - 1/4



Accumulated Material
(Sludges, etc.)
I/
Cubic feet/MG
3/4 - 3
3-8
5-30
Support Systems
Power for mechanically
cleaned racks,
conveyor belts,
grinders
As small as 5/8 -'
Flow Velocity:
0.75 to
1.0 ft/sec





Capacities: , /
0.35 to 25 MGD-
or
650-5,200 Ib/hr
Detention Time:
15-45 min.



Detention Titne-
(hr)
0.75 - 1.0
2.5


2.0 - 2.5


2.0

2.0


2.0


2.0
Mesh of Grit Overflow Rate
to Be Removed gal/sq ft/ day
35 73,000
48 51,000
65 38,000
100 25,000
Air Requirement:
.025 to .05 cu ft/gal




Air Requirement : I/
.005 to .2 cu. ft/gal
or 25 - 40 psi
Overflow Rates : ^/
2000-6000 gal/day/sq.ft
Overflow Rates
gal/day/sq ft
1,500 - 1,000
600

~
600 - 900


1,000

800


800


800
Cubic feet/MG
2-8










Volume of skimmings :
0.1 to 6 cu.ft/MG
or 200 cu.ft/
1OOO person/yr


Sludge accumula-
tion is approxi-
mately .038 cu ft/
capita or 3,500
gal/mg of flow












Power for mechanical
cleaning, cyclone
operations, and for
pumps to supply air.
Conveyor system to
remove grit.


Power:
1/4 to 3.5 hp motor


Cleaning units for
diffusers, power'
supply for air supply.


Cleaning mechanism
for units without
mechanical scrapers
and skimmers. Sludge
pumps and power supply
for those with pumps
and mechanical
skimmers.










                                     Weir loading rates:            .
                                      *-l MOD;  10,000 gal/linear ft-
                                    >1 MOD; 15,000 gal/linear ft
Chemical Precipitation





Chlorination— Chlorine
residual :
2 mg/1
Type of wastewater or
Contact time*
effluent:
15 min
Raw wastewater, depending
on strength and stale-
ness
Settled wastewater
Chemically precipitated
wastewater
Trickling filter effluent
Activated sludge plant
effluent
Intermittent sand filter
effluent












Probable Chlorine
Requirements

mg/1


6-25
5-20
3-20
3-20

2-20

1-10
Ib/day
per 1,000
persons*

5-21
4-17
3-17
3-17

2-17

1-3












2/
Chlorinatoi —
Capacities

mg/1


30
25
25
25

25

15

lb/1,000
persons*

23
20
20
20

20

12
Sludge contains
chemical high water
contentxand is twice
the volume produced
from plain sedi-
mentation
Scum and grease
accumulated in
contact chamber.









Dosing, mixing,
f locculation; and
sedimentation units;
where existing
sedimentation units
are not being used.
Chlorinators, chlorine
leak detection equip-
ment baffled contact
tank unless adequate
contact time is
provided in a waste-
water outfall or
conduit. Safety
equipment: Scott
air packs, cylinder
repair kits.
ventilation system.
Chlorine residual anal
yzer scales,
evaporators, CPRV

  * For background  information see Appendix  C
 »* For wastewater  flow of  100 gpcd
*»* For approx. specific gravity of 2.31
I/ Steel
2/ Imhoff-Fair
3/ 10-State Standards, 1971  edition
4' ASCE Std Manual
5/ Local requirements should prevail
                                                  19/20

-------
OPERATIONAL DATA ON SECONDARY WASTEWATER TREATMENT

-------
                                                   Table  II-2
                                        SECONDARY TREATMENT  DATA
Unit Operations
or Processes
Trickling Filters


Intermittent
Sand Filters
Stabilization Pond
or Lagoon^/
g g
(a) Facultative
(b) High rate
3. Aerated lagoons
4. Anaerobic
Operational
Parameters
Recirculation Rate for
Maximum BOD of Settled
Wastewater
.!/ Recirculation
BOD mg/1 Ratio
130 1:1
170 2:1
220 3:1
260 4 : 1
Depth of sand 3J-4 ft
Head on filter, 5 ft
Algae
Detention Concen-
(months) (ft) (mg/1)
7-30 2-5 10-50
2-6 j-1 100
1 or 2 - 14 6-15
30-50 8-10
Loading Rates
Low Rate High Rate
Hydraulic LondinE Filter Filter
gal/day/sq ft 25-100 200-1,000
million gal/acre/day 1.1-4.4 8.7-44
Organic Loading
Ib/acre ft/day 220-1,100 1,100-13,000
Loading 75,000-125,000
gal/acre/day
Solids 2 lb/5 sq ft/day
4/
Ib/acre/day
20-50
100-200
300-500
Support Systems

Dosaging tanks
recycle pumps
power supply

Dosing siphon of
flow distributor


Aerators
Final clarification
Following
Low-rate trickling filters
High-rate  trickling
 filters
Activated  sludge (over
 2.0 mgd)
Activated  sludge (under
2.0 mgd)
                         Overflow Data 3 5/>
                        gals/day/sq  ft —L~~
                           800-1,000

                               800

                           800-1,000

                               800
           Sludge pumps, power
           supply for mechanical
           sweepers, pumps
           recirculatlon pump
                            Detention Time (hrs) for
                          Overflow Rates & Depth of Tank—
            3/





Package Aeration
Plants

Overflow Rate
gal/day/sq ft
600
800
1,000

Flow Rate :

Depth
7 ft 8 ft 10 ft
2.1 2.4 3.0
1.6 1.8 2.25
1.25 1.4 1.75

400 gpc/dwelling
or 100 gpc/day





Organic load:
10-20 Ib BODs/1,000 cu ft
of areation tanks/day






Power supply
sludge pumps
                             Detention
                             Time for:   aeration tank 24  hrs
                                        clarifier      4  hrs
                   Air Supplied:
                    2,100 cuft/lb BCD/day
                             Recirculation rate:  1:1
Activated sludge
System fc ponds
(see table)
     For background information see  App. D.
     Unless otherwise noted
NOTE:  I/  Now parallel systems
       2/  After  1960, Eckenfelder, O'Connor
       3>  ASCE STD manual
4/ Algae concentration in
   suspension
5/ 10-State  Standards 1971
                                                        21/22

-------


Unit Operations
or Processes


Types of Process




Modified Aeration
(or high rate)
Conventional



Contact Stabilization
scheme 1
scheme 2


tO Two Stage Aeration
CO

to
Extended Aeration
Step Aeration


Completely mixed

Table I I -3
SECONDARY TREATMENT DATA - ACTIVATED SLUDGE PROCESS
Operational Parameters Loading Rates Support Systems
2/ Loadlngi/
Detention Time- Percentage Recycled Ibs BODs/
Type of Mixing Flow Scheme (hr) Sludge Ibs MLSS Air Requirements-
Plug Complete Aeration Aeration & Multi Stage
Flow Mixing Only Sludge Return Aeration
It Sludge
Return

x x 3 or less 10-50^ 1 or more .41 ft3/gal
x x 1-6 15-755/ 0.2-0.5 .4-1.5 ft3/gal
or
768-1000 ft3/lb BOD
Recycle pumps
diffusers
x x .5-1.0 SO-ISO^ 0,15-0.2 750 ft3/lb BOD Power ""PPl?
x x Contact range 1-4 0.15-0.2 removed sludge pumps
Stabilization tank alr compressors
air control
x x Contact range 0.07-0.15 system
1.5-3.0 sludge
Stabilization tank aeration
6_9 tanks
X x 24 hr 50-200- 0.01-0.07
3-8 20-75^' .2-0.5 of 500-700 «3/lb
50 lbs/1000ft3 BOD removed
of tank
3 or more 20-10O- .2-. 5 600 ft3/lb BOD
removed
n~
1





























Oxidation Ditch (Passover Ditch) Due to limited data at this time, no ranges for operational parameters or loading rates are possible.
I/ Ib of BOD Ib mixed
llauor suspended solids unless otherwise stated. American City, October 1971

2/ Steel, 1961.  Manual for EPA "Up Grading  Wastewater T.P."
3~/ Minimum air requirement, according  to  10-State Standards,  Is 1500 cu ft alr/lb BODs except extended aeration which  is  2000
4V Steel
5/ 10-State Standards, 1971

-------
OPERATIONAL DATA ON ADVANCED WASTE TREATMENT

-------
                                                   Table I1-4
                                        ADVANCED WASTE TREATMENT DATA*
    Unit Operations
      or Processes
                    Operational Parameters
                            Accumulated Material
                              Support Systems
    Chemical/Physical
        Treatment
                     Capacities as for
                     primary or secondary
                     clarifiers
                            From 200 to 900 mg/1
                            of additional sludge
                            (for phosphorus removal)
                            Mixing basin for dis-
                            persion of added chemicals,
                            pH measurement and
                            control equipment
    Carbon Absorp-
         tion
                     Contact time: 15 to
                     45 minutes.  Flow    ,
                     rates: 5 to 10 gpm/ft*
                            From 50 to 120 mg/1
                            of organic materials
                            Regeneration furnace
                            Filtration equipment
                            (where needed)
to
01
to
Ammonia
     Stripping
Air temperatures above
32°.  pH between
10.8 and 11.5
Ammonia is carried off
into atmosphere.
Some carbonate scale
and sludge buildup.
Power for forced draft.
Coupling with
phosphorus removal.
Recarbonation equipment
     Electrodialysis
                     Flow rate: up to
                     10 MGD.  More
                     efficient at higher
                     temperatures
                            Brine stream 10-25%
                            of feed stream
                            Electric power for stacks
                            Brine disposal system
     Reverse  Osmosis
                     Flow rate: up to
                     50 MGD.  More effici-
                     ent at higher
                     temperatures
                            Brine stream
                            10-25% of feed
                            stream
                            Power for high pressure
                            pumps (600 psi)
                            Brine disposal system
     *For background information,  see Appendix E.

-------
OPERATIONAL DATA ON SOLIDS TREATMENT

-------
                                          Table  II-5

                                   SOLIDS TREATMENT  DATA*
Unit Operations Operational Loading Rates
or Processes Parameters
Anaerobic pH 6.8-7.2 Loadln of Heated
Digestion Temperature 85-95°F Jt tile
Detention 30 days ' "
Gas production 12 cu ft/lb solids per cu It
volatile PGT monthi/
matter Conven-
Sludge produced for red tional High-rate<
-------
to
to
co
o
                                                           Table  II-6
                                               COMMON SOLIDS TREATMENT  DATA*
Amounts of Chemicals Commonly Employed in Conditioning
Unelutriated Sludge and Yields of Vacuum Sludge Filters






Type of Sludge
Plain sedimen-
tation (primary)
1. Fresh sludge
2. Digested
sludge


Condi-
tioner,
% of
dry
sludge
solids
CaO FeCl
O


10 3

10 2
0 6


Dry
Solids
Ib per
1,000
persons
daily


143

89
78


Filter
Capacity
Ib per
sq ft per
hr, dry
basis


5

6
6

Required
Filter
Area, sq
ft per
Cake 1 , 000
Solids persons
% daily


32 1.2

32 0.6
28 0.5


Sludge
Cake,
Ib per
1,000
persons
daily


450

280
280

Condi-
tioner,
Ib per
1,000
persons
daily
CaO FeCl,
o


12 3.6

7.5 1.5
0 4.5







Support System
Dosing equipment
Power supply
Sludge pumps
Elutriation
tanks
Chemi cal

storage
Plain sedimen-
tation and low-
rate trickling
filtration

3. Fresh sludge
     mixture      12    3
4. Digested mixed
     sludge       12    2
                   0    7

Plain sedimen-
tation and con-
ventional acti-
vation
                                    183

                                    117
                                     99
6
6
28

30
26
1.9

0.8
0.7
650   18

390   11
380    0
4.4

1.9
6.7
5.

6.

7.

Fresh activated
sludge
0
6
71
2.5
20
1.2
350
0
4.
1
Fresh settled
sludge
Digested
sludge
mixture 0
mixed
0
6

8
195

129
4

2.5
22

22
2.1

2.1
880

580
0

0
11

9.


7
        *Adapted  from Imhoff-Fair,  2nd edition.   For  background information,  see Appendix F.

-------
SAMPLING/TESTING

-------
Ill
SAMPLING
AND  TESTING

-------
                                Section III

                           SAMPLING AND TESTING
INTRODUCTION

    The sampling and testing program described in this section is designed
to determine

        9  the type of sampling to be done

        •  the locations of sampling points
        •  the analyses to be performed for the particular
           treatment system.

In addition,  recommended storage temperatures and durations are given,  as
well as a list of the laboratory equipment that will be needed to perform
the various analyses.  Sample forms are included which are intended as
aids for the systematic recording of the results of the various analyses.

    The information in this section can be used with the problem/solution
section of this manual (Section IV) either to establish a sampling and
testing program to solve a particular problem involving a particular
process, or to institute an adequate sampling program at a plant lacking
such a program.

    A comparison of the type and frequency of tests needed to control the
various processes with the sampling program actually being performed at
the plant site can help evaluate the process control system of the plant.
In the overall evaluation of the plant,  this comparison would be used in
ratings of the sampling and testing program, and the laboratory facility to
perform necessary tests.


GENERAL

    The characterization of waste, whether it be domestic or industrial in
origin, begins with sampling.  A wastewater treatment plant consists of
various components which make up the treatment system.  A program of
sampling and testing which measures influent, effluent•and1individual
process units on a scheduled basis not only means better plant performance
but can also indicate problems quickly so that immediate corrective
measures can be taken.

    The extent of any testing program should depend on the size and type
of treatment facility and the type and quality of receiving waters; how-
ever,  it probably will depend on the time which can be made available for
that purpose, together with the number of persons who staff the laboratory
                                     31

-------
facilities.  The treatment plant should be provided with adequate laboratory
facilities for the performance of tests necessary for the proper operation
of the plant.

    Some more sophisticated treatment plants are provided with instrumenta-
tion which allows for constant monitoring of certain treatment processes
and it is customary for this information to be telemetered and recorded
at some convenient location within the plant control building.  Telemetered
information can include,  but not be limited to,  primary effluent pH, final
effluent chlorine residual,  aeration tank dissolved oxygen, and sludge
density.  Even though the instruments performing these monitoring functions
can be highly reliable, it is recommended that their performance be checked
periodically by analyzing concurrent and identical samples.


THE SAMPLING PROGRAM

    A well-organized, effective sampling program must consider several
factors:

        •  Type and scheduling of sampling needed for the  specific
           analyses to be made

        •  Quantity of samples needed

        •  The most effective sampling locations

        •  Handling and storage procedures (between sampling
           point and testing site)
        •  Types of sample testing to be done.

    Tables III-l and III-2 indicate the common constituents which are
analyzed from the flows of various treatment processes.  The matrix
(Table  III-2) also indicates points in the treatment system where samples
should  be taken.  The indicated sampling frequencies are minimum values and
are dependent on or can vary with size of plant and staff, complexity of
the system, the nature of the waste handled, and on the effluent require-
ments placed on the facility.

    The test indicated should be performed as frequently as indicated in
accordance with the prevailing requirements of the agency  governing waste
discharge within the area in which the plant is located.   Every effort
should  be made to perform the tests in accordance with their scheduled
frequency.  A test with a "weekly" frequency should be run at a regular
hour and day of the week.
                                     32

-------
                                       Table III-l

                                PROCESS TESTING GUIDE*
PROCESS
Grit
Removal
P R I
Primary
Sedimentation
S
Activated
Sludge
Trickling
Filter
Oxidation
Ponds
Final
Sedimentation

TEST FREQUENCY
PRETREATMENT
Volatile Solids
Total Solids
Moisture Content
MARY TREATMENT
Settleable Solids
pH
Total Sul fides
Biochemical Oxygen Demand
Suspended Solids
Chemical Oxygen Demand
Dissolved Oxygen
Grease
3CONDARY TREATMENT
Suspended Solids
Dissolved Oxygen
Volatile Suspended Solids
Turbidity
Suspended Solids
Dissolved Oxygen
Dissolved Oxygen
Total Sulfides
Total Organic Carbon
Total Phosphorus
Settleable Solids
pH
Total Sulfides
Biochemical Oxygen Demand
Suspended Solids
Chemical Oxygen Demand
Dissolved Oxygen
Turbidity
M B A S
Daily
Daily
Daily
Daily
Daily
Daily
Weekly
Weekly
Weekly
Weekly
Weekly
Daily
Daily
Weekly
Daily
Daily
Daily
Daily
Daily
Weekly
Weekly
Daily
Daily
Daily
Weekly
Weekly
Weekly
Weekly
Daily
Weekly
PROCESS
Chlorination
S
Thickening
Digestion
Centrifuging
Vacuum Filters
Incineration
TEST
DISINFECTION
Chlorine Residual
MPN Coliform
OLIOS HANDLING
Suspended Solids
Volatile Solids
Total Solids
Volatile Solids
pH
Gas Analysis
Alkalinity
Volatile Acid
Suspended Solids When
Volatile Solids When
Sludge Filter- When
ability
Suspended Solids When
Volatile Solids When
Ash Analysis When
FREQUENCY
Daily
Weekly
Daily
Daily
Weekly
Weekly
Daily
Weekly
Weekly
Weekly
in Operation
in Operation
in Operation
in Operation
in Operation
in Operation
ADVANCED TREATMENT
Chemical
Coagulation t
Flocculation
Activated
Carbon
Reca rbona t i on
Ammonia
Stripping
Filters
Microscreen

Jar Test
Phosphorus Analysis
Apparent Density
COD
TOC
pH
Ammonia Nitrogen
pH
Suspended Solids
Turbidity
Suspended Solids
Chemical Oxygen Demand
Weekly
Weekly
Weekly
Weekly
Weekly
Weekly
Weekly
Weekly
Daily
Daily
Daily
Weekly
This is a minimum sampling guide, and is subject  to change with plant site,
complexity of operation, and problems encountered.
                                             33

-------
                                Table III-2

                          EQUIPMENT TESTING  MATRIX*

                  EQUIPMENT NEEDED


CONSTITUENTS
TO BE ANALYZED
Volatile Solids
Total Solids
Settleable Solids
PH
Total Sulfides
Biochemical Oxygen Demand
Chemical Oxygen Demand
Suspended Solids
Dissolved Oxygen
Chlorine Residual
MPN Coliform
Volatile Acids
Alkalinity
Gas Analysis
Grease
Total Organic Carbon
Turbidity
Volatile Suspended Solids
Total Phosphorous
MBAS
Sludge Filterability
Ash Analysis
Jar Test
Apparent Density
Iodine Number
Isotherms
Calcium Content
Ammonia Nitrogen
Organic Nitrogen
Nitrate Nitrogen
Heavy Metals


Atomic Absorption.
600° C Muffle Furnace
103° C Drying Oven
Analytical Balance
Imhoff Cone
• • •
• •
•




• •






• •


• • •



• •

•

• •
•



*
5
1
o
_c
o
E
c
o
- -5 i -I
,_ ^ u a. a, ID
5 t5 -C 3 °^ °
^ 3 S > I v



•
•
•
•
•



•
•

• •


•
•

• •




«

•
• •



I Ji
11
Condenser & Extraction Equi
Dissolved Oxygen Meter &
Autoclave
Amperometric Titrator
Sterlilizing Oven






•

•
•

•


•












•
•




35° C Incubator
Gas Analyzer
Steam Bath
Magnetic Stirrer
Blender






•





•
•
•


















Turbidity Meter
Carbon Adsorption Unit
Desiccator
Spectrophotometer
Stirring Equipment
•
•





•








•
•

•


*


,
•


«


S
!
j
j j
^ 1 £ -
0) 8) U ~
.E (5 5 «
Illl





• •
• •




• •



•







•

,





*The equipment specified in this matrix is subject to plant size and com-
 plexity of processes and the degree of control  required.
                                     34

-------
Types of Sampling

    Sampling can be either of two types:

        1.   Grab.  This type of sample is taken when wastewater does
            not flow continuously, when appearance of discharge
            changes rapidly, and when making sure that the composite
            sample isn't masking extreme conditions of the waste.
            It is also used when test samples cannot be mixed, such
            as when testing for residual chlorine, dissolved oxygen,
            or pH.

        2.   Composite.  With the widely varying characteristics of
            waste, this type of sampling provides a representation of
            wastewater over a period of time and can be composited
            on the basis of proportional flow or the same amount
            being collected at every interval during the sampling
            period.  Composites should be corrected as specified in
            Standard Methods.

Location of Sampling Points

    Samples should be taken only where the wastewater is well mixed.  If
large particles are found in the sample, they should be broken up to make
a more homogeneous sample.  Deposits or growths of floating material
which have formed at the sampling point should not be included in the
sample.

Quantity of Sample

    In order to determine the correct amount of sample to be collected,  the
past flow records of the plant should be analyzed to determine the daily
average flow.  The amount of the composite sample to be collected at a
given period should be proportional to flow of wastewater at that time.
Then determine the quantity of sample needed for analysis; 1 liter is
usually sufficient; never try to work with less than about 200 ml.

Handling and Storage of Samples

    Samples should be tested as soon as possible.  If testing must be
delayed, then adequate storage must be provided.  Table II1-3 recommends
appropriate storage temperature and duration in terms of the test to be
performed on the stored sample.
                                    35

-------
                                Table II1-3

                      STORAGE TEMPERATURE AND TIME-
ANALYSIS
Total solids
Suspended solids


Volatile sus-
pended solids


COD


BOD




TEMPERATURE
4°C
4 C


4°C


o
4 C







TIME

Up to
several
days
Up to
several
days

Up to
several
days
Up to one
day in com-
posite
sampling
systems
TEMPERATURE

0°C


0°C


o
0 C







TIME

No storage


No storage



Unlimited


Lag develops,
must use
fresh
sewage
seed
Source: Agardy,  F.J.,  and M.L.  Kiado,  Effects of Refrigerated Storage on
        the Characteristics of  Waste,  21st Industrial Waste Conference,
        Purdue University,  May  3-5,  1966.

        I/For more detailed preservation techniques,  see Analytical
        ~~ Quality Control,  EPA  Chemical Methods, or Standard Methods.

Test Records

    In order that the data developed through the plant sampling program can
be properly utilized to gage plant performance, it is necessary that it be
systematically recorded and filed for ready reference.  The most practical
means of satisfying this requirement is to prepare convenient forms on
which these data can be recorded.  These forms should be prepared to fit
the particular operating conditions at each individual plant.  The data
should be recorded chronologically on these forms and should be organized
so that each set of data can be utilized to evaluate a particular aspect
of the treatment process.  Proper recording of sampling data will allow
for more efficient and expedient solution of operational problems.  Several
examples of operational forms are included at the end of this section
which can be utilized for the recording of analytical data pertinent to
the treatment process.
                                     36

-------
    In addition to recording the data on forms, graphing of pertinent
operating parameters may be appropriate and desirable for visual presenta-
tion.
                                     For additional information on
                                     sampling and testing, see:
                                     State of Washington Wastewater
                                       Plant Operator's Manual
                                     Operation of Wastewater Treatment
                                       Plants: A Field Study Training
                                       Program, EPA
                                     Effects of Refrigerated Storage
                                       on the Characteristics of Waste,
                                       21st Industrial Waste Conference,
                                       Purdue University
                                     Standard Methods, 13th Ed
                                     Collection, Storage, Transportation
                                       and Pretreatment of Water and
                                       Wastewater Samples by Sanitation
                                       and Radiation Laboratory,
                                       California State Dept. of
                                       Public Health
                                     MOP 11
                                     BOP 18
                                     37

-------
                                                SAMPLING  PROGRAM  FREQUENCY AND  LOCATION
PARAMETERS TO  SAMPLE
PROCESSES
PRETREATMENT
Grit Removol
PRIMARY TREATMENT
Sedimentation
SECONDARY TREATMENT
Activated Sludge
Trickling Filter- Single Stoge
Trickling Filter - Two Stage
Oxidation Pondi
Final Sedimentation
Package Aeration Planti
Imhoff Tanks
DISINFECTION
Chlorinotion
SOLIDS HANDLING
Thickening
Digestion
CentrifuQing
Vacuum Filter!
Incineration
ADVANCED WASTE
TBEATMENT
<
S
















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-------
                       SAMPLE FORMS  TO BE USED WITH
                 A SAMPLING AND TESTING PROGRAM ANALYSIS
                              AND EVALUATION
*
 Forms to be developed an'd Inserted by field inspectors
                                     39

-------
PROBLEMS/SOLUTIONS

-------
IV

COMMON  OPERATING
PROBLEMS  and
SUGGESTED SOLUTIONS

-------
                     COMMON OPERATING PROBLEMS

                                   and

                         SUGGESTED SOLUTIONS

INTRODUCTION

    There is a variety of common operating problems which may occur period-
ically and prevent the proper processing of wastes by a treatment plant.

    The purpose of this section is to properly identify the problem by
defining the indicators.  Once the problem has been identified,  certain
monitoring,  analyses and/or inspections must be performed prior to making
a decision as to which corrective measures should be utilized.  In some
cases, the data-gathering process can be a simple visual observation and  in
other cases it can involve rather intricate sampling and laboratory pro-
cedures.  The resulting information should then be systematically utilized
to make a determination on which of the corrective measures should be
implemented.

    The problems discussed in this section are those which occur rather
frequently in practice and the suggested solutions have been,  for the most
part,  accepted procedure in the industry.    There may be times when the
suggested corrective measures do not correct the problem,  or a problem
may exist which does not fit into the common category.   In a case such as
this,  it is prudent to seek expert advice on the subject prior to under-
taking any course of action.  The information utilized in development of
the indicators and solutions reflect the present state-of-the-art;  as
information from new technical advances becomes available,  this section
will be updated.
                                    41

-------
                      PROBLEM  INDEX
                                                            Page
                  I.    PRETREATMENT
                 /
PUMPING PLANTS AND INFLUENT SEWERS
     Surging of plant influent                               49
     Accumulation of solids or scum in wet wells              51
     Odor source in wet wells                                 52
SCREENING AND SHREDDING
     Accumulation of rags and debris for disposal            53
     Excessive grit in bar screen chambers                   54
     Odor source in grit chamber                             55
     Shredded screenings clogging pumps                      56
GRIT HANDLING AND REMOVAL
     Grit removed has high organic content                   57
GENERAL
     Industrial waste is inadequately pretreated             58

             II.    PRIMARY   TREATMENT

PRIMARY SEDIMENTATION TANKS
     Floating, gaseous, or septic sludge in tanks            59
     Low settleable solids removal efficiency                60
     Erratic operation of sludge collection mechanism        61
     Low scum (grease) removal                               62
     Tank contents turn septic                               63
                                43

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                                                             Page
          III.    SECONDARY   TREATMENT

ACTIVATED SLUDGE PROCESS
     Sludge bulking                                            64
     Erratic sludge volume indexes                             65
     Difficulty in maintaining balanced mixed liquor
         dissolved oxygen                                      66
     Excessive foam in aeration tanks                          67
     Digester supernatant and/or centrifuge centrate
         upsetting activated sludge process                    68
     Unable to maintain balanced food/micro-organism
         ratio in aeration unit                                69
     Facilities inadequate for disposal of waste activated
         sludge                                                70
     Uneven hydraulic and solids loading of aeration tanks     71
TRICKLING FILTERS
     Ice buildup on media                                      72
     Filter odors                                              73
     Fly nuisance in vicinity of filter                        74
     Clogging and ponding of filter media                      75
     Clogging of distributor nozzles causes uneven
         distribution of flow on the filter surface            76
OXIDATION PONDS
     Excessive weeds and tules                                 77
     Pond odors                                                78
     Low pond dissolved oxygen                                 79
FINAL SEDIMENTATION
     Sludge or pin floe flowing over weirs                     80
     Erratic operation of scraper mechanism                    81
                                44

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                                                              Page
            IV.    ADVANCED   TREATMENT

CHEMICAL COAGULATION AND FLOCCULATION
     Chemical coagulants utilized for settling or
         dewatering sludges through recycling cause
         floating sludges in primary sedimentation tanks       82
AMMONIA STRIPPING
     Freezing in ammonia stripping tower                       83
     Formation of calcium carbonate scale on ammonia
         stripping tower fill and structural members           84
FILTERS
     Filter backwash wash water hydraulically overloads
         and upsets clarifiers                                 85
MICROSCREEN
     Fouling of fabric with grease and solids                  86
     Microscreen effluent exhibits higher suspended
         solids content than influent                          87
ACTIVATED CARBON
     Mechanical fouling of columns                             88
                  V.    DISINFECTION
CHLORINATION
     Insufficient chlorine gas pressure at the
         chlorinator with all cylinders connected
         to gas phase.                                         89
     Insufficient chlorine gas pressure at the
         chlorinator                                           90
     There is no chlorine gas pressure at the
         chlorinator, when apparently full chlorine
         cylinders are connected to the chlorine
         supply system.                                        91
                                45

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                                                         Page

Impossible to operate chlorinator because
    rotameter tube ices over and feed rate
    indicator is extremely erratic.  Chlorine
    supply is from ton containers connected
    to the gas phase.                                       92
Chlorinator will not feed any chlorine even
    though all systems appear normal.                       93

Chlorine gas is leaking from vent line connected
    to external chlorine pressure reducing
    valve (CPRV)                                            94
Inability to maintain chlorine feed rate without
    icing of chlorine supply system between
    external chlorine pressure reducing valve
    and chlorinator.  (Equipment consists of
    evaporator, external CPRV and the
    chlorinator.)                                           95

Chlorination facility consisting of evaporator-
    chlorinator combination with external chlorine
    pressure reducing and shut-off valve is unable
    to maintain water-bath temperature sufficient
    to keep external chlorine pressure reducing
    valve in open position.                                 96

Inability to obtain maximum feed rate from
    chlorinator or chlorinators with adequate
    chlorine gas pressure at chlorinator.                   97

Inability to maintain adequate chlorine feed rate           98
Inability to obtain maximum or proper feed rate
    from chlorinator with adequate gas pressure
    at chlorinator.                                         99

Excessive chlorine odor at point of application             100

Chlorinator will not feed enough chlorine to
    produce a proper chlorine residual at the
    sampling point.                                         101
Wide variation in chlorine residual in effluent
    as determined by hourly chlorine residual
    determinations.                                         102

Chlorine residual analyzer recorder controller
    does not appear to control the chlorine
    residual properly.                                      103
                           46

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                                                              Page
     Chlorination system consists of either
         compound-loop control or direct residual
         control and system does not appear to be
         controlling properly.                                 105
     Coliform count does not meet the required
         disinfection standards set by regulatory
         agencies.                                              106
     Coliform count does not meet the required
         standards for disinfection.                           107
     Plant effluent does not meet toxicity requirements
         because chlorine residual to achieve proper
         disinfection is at too high a level.                  108
                      VI.    METERING

     Plant meter unreliable                                    109

              VII.    SOLIDS   HANDLING

SLUDGE THICKENERS
     Odor from thickener                                       111
     Thickener contents do not settle                          112
     Sludge pumped from thickener has low solids
         concentration                                         113
SLUDGE DIGESTION  (Anaerobic)
     Scum blanket in tank                                      114
     No digester gas production                                115
     Increase in volatile acid/alkalinity ratio
         in digester                                           116
     Foam in digester                                     •     117
     Low reduction of volatile solids in digester              118
     High percent solids in digester supernatant               119
CENTRIFUGING
     Low solids recovering rate                                120
                                47

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                                                              Page
VACUUM FILTERS
     Low solids recovery                                       121
INCINERATION
     Abnormally high temperature in' furnace                    122
     Abnormally low temperature in furnace                     123
     High oxygen level in furnace stack exhaust                124
     Low oxygen level in furnace stack exhaust                 125
SLUDGE LAGOONING
     Excessive solids carried over from lagoon
         supernatant to plant influent                         126
     Odors from sludge lagoons                                 127
                                48

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                PRETREATMENT - Pumping Plants and Influent Sewers
Problem
SURGING OF PLANT INFLUENT
Indicators      1.  Intermittent flooding of weirs and structures.

                2.  Plant efficiency treating wastewater drops sharply for
                    short period of time.
                3.  Flow meter records intermittent high and low peak flows.
Monitoring,
Analysis
and/or
Inspection
1.  If a main sewage lift station pumps effluent to plant,
    check for frequent starting and stopping of pumps or more
    than one pump operating at one time (out of phase) during
    a pumping cycle.
2.  If influent flows to the plant by gravity through a main
    trunk, check depth of flow in connecting sewers if
    channel is uniform or monitor flow with a portable flow
    meter.
3.  If surging occurs during rainfall, record relation of
    surging to duration of rainfall; and record or obtain
    rainfall intensity if possible.
Corrective
Measures
    Surging from gravity influent line indicates a major
    pump station discharge into a connecting sewer.  Review
    water depth and/or portable flow meter data to determine
    source of  flow.
    Intermittent starting and stopping or recycling of main
    influent pump station or stations indicates improper wet
    well sensor adjustment or that the hydraulic capacity of
    the station has been exceeded.  Adjust level sensors for
    a more desirable pumping cycle.  If possible, install
    variable speed pumps units for uniform flow into
    treatment  plant; or install surge tank.

    Heavy surging or hydraulic loading of treatment plant
    treating waste from a separated system during periods of
    normal rainfall indicates illegal connections to system
    such as catch basins, yard drain, or roof downspouts.
    "Smoke bomb" sanitary sewer system to determine source
    of illegal connections.
    Heavy surging or hydraulic loading of treatment plant
    during period of heavy rainfall is caused primarily by
    flooding of street areas and water entering the system
    through manholes, broken lines, etc.  Seal all manhole
    covers in  high risk flood areas and patch all cracks in
    manhole structures with an epoxy water resistant compound.
                                     49

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            I.   PRETREATMENT - Pumping  Plants and Influent Sewers
Problem
SURGING OF PLANT INFLUENT
Indicators   1.  Intermittent flooding of weirs and structures.

             2.  Plant efficiency treating wastewater drops sharply
                 for short period of time.
             3.  Flow meter records intermittent high and low peak flows.

             4.  Excessive suspended solids in overflows.

Monitoring.  1.  If a main sewage lift station pumps effluent to plant,
Analysis         check for frequent starting and stopping of pumps or more
and/or           than one pump operating at one time (out of phase) during
Inspection       a pumping cycle.
             2.  If influent flows to the plant by gravity through a main
                 trunk, check depth of flow in connecting sewers if channel
                 is uniform or monitor flow with a portable flow meter.
             3.  If surging occurs during rainfall, record relation of
                 surging to duration of rainfall; and record or obtain
                 rainfall intensity if possible.

Corrective       Surging from gravity influent line indicates  a major  pump
Measures         station discharge into a connecting sewer.  Review water
                 depth and/or portable flow meter data to determine source
                 of flow.
                 Intermittent starting and stopping or recycling of main in-
                 fluent pump station or stations indicates improper wet well
                 sensor adjustment or that the hydraulic capacity of the sta-
                 tion has been exceeded.  Adjust level sensors for a more
                 desirable pumping cycle.  If possible,  install variable
                 speed pump units for uniform flow into  treatment plant; or
                 install surge tank.
             3.  Heavy surging or hydraulic loading of treatment plant treat-
                 ing waste from a separated system during periods of normal
                 rainfall indicates illegal connections  to system such as
                 catch basins, yard drain, or roof downspouts.  "Smoke bomb"
                 sanitary sewer system to determine source of  illegal
                 connections.
             4.  Heavy surging or hydraulic loading of treatment plant
                 during period of heavy rainfall is caused primarily by
                 flooding of street areas and water entering the system
                 through manholes, broken lines, etc.  Seal all manhole
                 covers in high risk flood areas and patch all cracks  in
                 manhole structures with an epoxy water  resistant compound.
                                     50

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                PRETREATMENT - Pumping Plants and Influent Sewers
Problem
ACCUMULATION OF SOLIDS OR SCUM IN WET WELL
Indicators      1.  Scum blanket in wet well

                2.  Odors
                3.  Improper operation of level sensing equipment
Monitoring,
Analysis
and/or
Inspection
1.  Sound wet well with a pole to determine solids level.

2.  Measure wet  well draw down during pumping cycle.
3.  Ascertain relation of pump suction piping to floor of
    wet well.
4.  Determine elevation of inlet piping.
5.  Look for dead spots in corners and structural cracks
    where sludge can accumulate.
Corrective
Measures
    Start pumps manually, being careful not to break suction,
    and pump wet  well down to lowest possible elevation while
    breaking scum blanket with a high pressure water hose.
    Check pumping level and determine if more of a drawdown
    can be allowed for in order to remove more of the
    floatable materials.
    If one or more influent line come in at a higher elevation
    than the pump suction inlet, set level sensor so drawdown
    will allow for spillage of fresh wastewater onto the scum
    blanket.  The resultant turbulence could assist in
    breaking the blanket.
    If this is a persistent problem install air diffusers in
    wet well with compressors wired to operate in tandem with
    the pumps.  Diffused air will assist in placing the
    solids in suspension and curtail the development of a
    scum blanket.
                                      51

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            I.  PRETREATMENT - Pumping Plants and Influent Sewers
Problem
             ODOR SOURCE IN WET WELL
Indicators
Monitoring,
Analysis
and/or
Inspection
             1.  Odors of hydrogen sulfide origin
             2.  Corrosion of iron work and concrete

             3.  Black color observed in liquid or solids

             1.  Hang hydrogen sulfide (lead acetate) indicator
                 tiles in wet well.

             2.  Sample wastewater in wet well and analyze for total
                 and dissolved sulfides.
             3.  Check for floating solids in wet well.

             4.  Run dye test on influent sewer or sewers to determine
                 velocity of waste flow and travel time to wet well.

             5.  Check temperature of wastewater in wet well.
             6.  Check pump invert position and condition.
             7.  Check passage time in the interceptors at flow velocities.

Corrective   1.  Low velocities (less than 2 ft/sec) are an indication
Measures         that solids are being deposited in influent sewer and
                 sulfides are being formed and released in the wet well.
                 Velocity must be increased in the sewer or influent must
                 be continuously treated upstream with chlorine or copperous
                 to prohibit the development of hydrogen sulfide gas.

             2.  If the source of hydrogen sulfide is in the wet well and
                 not the influent sewer,  increase pumping cycle for more
                 frequent removal of solids.

             3.  Install air diffusers in wet well to keep wastewater fresh.
             4.  Install blower and gas scrubber for the oxidation of the
                 gases and exhausting to the atmosphere.
             5.  Dose wet well with hyperchloride on a periodic basis to
                 suppress the formation of hydrogen sulfide.
                                    52

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                 I.   PRETREATMENT - Screening and Shredding
Problem
ACCUMULATION OF RAGS AND DEBRIS FOR DISPOSAL
Indicators
    Large amount of rags and debris accumulated on plant
    site gives off obnoxious odors and attracts flies and
    other insects.
Monitoring,
Analysis
and/or
Inspection
2.
3,
Estimate volume (cubic feet) of rags and debris removed
each day in proportion to flow.
Determine time exposed material is allowed to accumulate.
Check disposal method used.
Corrective      1.  Arrange for local refuse or garbage company to pick up
Measuresrags and debris on a daily basis and dispose of them in
                    a sanitary fill.
                2.  Store rags and debris in closed containers whenever
                    possible.
                3.  If incineration facilities are available on plant site
                    or at some other convenient location, burn them.  Care
                    must be taken to see that the emission from the
                    incinerator meets location air pollution control
                    requirements.
                4.  Rags and debris can be disposed of on the plant site if
                    sufficient land is available for a fill and cover
                    operation.
                5.  If none of the above methods proves feasible, rags and
                    debris can be ground up by installing the proper
                    equipment and returned to the plant flow.  This method
                    should only be used as a last resort since ground or
                    shredded screenings may cause problems in pumping
                    equipment and in digesters.
                                      53

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                 I.  PRETREATMENT - Screening and Shredding
Problem
EXCESSIVE GRIT IN BAR SCREEN CHAMBERS
Indicators      1.  Surging in chamber due to increase in water level.
                2.  Low removal of grit by degritting equipment.
                3.  Excessive dryout of grit with screening.
Monitoring,
Analysis
and/or
Inspection
1.  Sound chamber with flat board at end of pole to determine
    depth of grit.

2.  Determine velocity in chamber by timing a dye release
    from one end of chamber to the other.

3.  Check plans and probe bottom of chamber to determine
    whether there are any irregularities in chamber bottom
    slope.
4.  Check channel when dewatering for regularly scheduled
    maintenance.
Corrective      1.  If velocity in chamber is less than 2 ft/sec, flush
Measures            chamber regularly with high pressure water hose.  If
                    slide gates are available at inlet end of chamber,
                    throttle gates to jet flow along chamber bottom.

                2.  Remove irregularities or reslope chamber bottom; if
                    possible, to increase velocity.

                3.  Regulate velocity in grit chamber by utilizing different
                    outlet weir shapes.
                                     54

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                  I.  PRETREATMENT - Screening and Shredding
Problem      ODOR SOURCE IN GRIT CHAMBER

Indicators   1.  Odors of hydrogen sulfide origin

             2.  Corrosion of metal work and concrete
Monitoring,   1
Analysis
and/or
Inspection   3
Corrective
Measures
5.

6.

7.

1.

2.

3.
Hang hydrogen sulfide (lead acetate) tiles in chamber.
Check velocities through grit chamber

Check volatile solids content of the grit.
Sample wastewater in chamber and analyze for total
and dissolved sulfides.
Check for floating solids in chamber.

Measure depth of grit in chamber.

Check for submerged rags and debris on bar screen.

Clean bar screen thoroughly so as not to impede flow.

Increase velocity to 1 fps.
Wash grit chamber thoroughly daily with high pressure
water hose to move sludge and floating solids through
screens.
Dose chamber with hyperchloride on a periodic basis to
suppress the formation of sulfide.  Excessive doses of
this chemical should be avoided as it can be toxic to
biological treatment systems and anaerobic digestion
systems.
Install blower and gas scrubber for the oxidation of
gases and exhausting to the atmosphere.
                                     55

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                    I.  PRETREATMENT - Screening and Shredding
Problem
Indicators
SHREDDED SCREENINGS,  CLOGGING PUMPS
1.

2.

3.

4.
Monitoring,   1,
Analysis
and/or
Inspection
Corrective   1.
Measures
             3.

             4.
Rope-like rags and debris wrapped around pump impellers.
Pump suction lines plugged with "bundles" of rags.
Excessive pump or drive beating and power requirements.
Appearance of chunks larger in size than usual in
the shredder discharge.

Install pressure gages on discharge side of pump and
check pressure daily.
If pump discharge line visible, check flow daily.
Check power input, bearing heat pressures on inlet
and discharge sides.
Check driver speed and power train for power use and
delivery to the shredder.

Do not shred screenings and return them to flow.  Remove
them either mechanically or manually and dispose of them
by burial.
Check cutters periodically on all barminutors,
comminutors, and other shredding equipment for sharpness.

Back flush pumps, periodically if possible.
If necessary, modify pump type, inlet protection or
prior protective devices to avoid recurred plugging.
Upgrade screening and grit removal operation.
                                    56

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                 I.  PRETREATMENT - Grit Handling and Removal
Problem
             GRIT REMOVED HAS HIGH ORGANIC CONTENT
Indicators   1.
             2.
             3.
Monitoring,   1.

             2.
Analysis
and/or
Inspection
Corrective
Measures
             3.
             4.
             3.
             4,
Grey color of grit
Odors from grit
Greasy feel with excessive components

Run volatile solids test on grit daily.
Check discharge pressure on cyclonic grit removal
equipment.
Check velocities with dye releases in grit chambers.
If grit chamber is aerated, check air flow rate to
chamber.
Visual examination of grit and identification of
origin of grit materials.

Keep pressure on cyclonic grit removal equipment at
an acceptable range (usually between 4 and 6 psi) by
governing pump speeds.
Increase velocities in grit chambers by whatever
means possible.
Adjust air accordingly.
Check inlet and outlet controls, baffles and
mechanical equipment; adjust and  repair and keep
clean.
                                    57

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                         I.   PRETREATMENT - General
Problem
INDUSTRIAL WASTE IS INADEQUATELY PRETREATED.
Indicators      1.  Discoloration of influent
                2.  Sterilization of biological treatment processes
                3.  Digester upsets
                4.  Change in influent odor
                5.  Unusual amounts of solids in influent
Monitoring,
Analysis
and/or
Inspection
1.  Constantly monitor influent for pH above 8.0 or below 6.0.
2.  Check pH of raw sludge.
3.  Run heavy metal tests on influent.
4.  Check influent temperature.
5.  Run settleable solids test.
6.  If toxic flow is constant, attempt to trace source
    upstream of treatment plant.
7.  Run C.O.D. test on contaminated effluent and compare
    results with normal plant loading.
Corrective      1.  Bypass all biological treatment processes  to  parallel
Measuresunits as soon as contaminant has been detected.
                2.  Isolate and dispose of all contaminate sludges.
                3.  If digesters show increases in volatile acids because of
                    contaminated sludges, see Section VII(b) for corrective
                    measures.
                4.  If activated sludge process has become contaminated,
                    dispose of floe and restart process.
                5.  Institute program of source control  (industrial waste
                    ordinances).
                                     58

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            II.  PRIMARY TREATMENT - Primary Sedimentation Tanks
Problem
FLOATING, GASEOUS, OR SEPTIC SLUDGE IN TANKS
Indicators      1.  Floating material in tank deadspots or in scum troughs
                2.  Odors of hydrogen sulfide origin
Monitoring,
Analysis
and/or
Inspection
1.  Run total solids tests on raw sludge being pumped from
    primary sedimentation tanks with sample being taken at
    beginning and end of pumping cycle.
2.  Dewater tanks and check sludge collector mechanism
    (flights, chains and scrappers) for wear and tear.

3.  Observe conditions of tanks prior to chemical
    treatment of tank influent.
Corrective      1.  If total solids of raw sludge analyzed at end of pumping
Measurescycle is over 2%, increase duration of pumping cycle,
                    preferably with a timer.
                2.  If sludge collector mechanism shows signs of wear during
                    inspection, repair or replace.

                3.  Certain chemicals, such as alum, used in chemical
                    treatment, cause floating sludge if this chemical is
                    recirculated to the primary sedimentation tanks.  Change
                    operating procedures or chemicals used.
                4.  Long detention in sludge hoppers favors production
                    of a sludge that readily slips.
                                     59

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            II.   PRIMARY TREATMENT - Primary Sedimentation Tanks
Problem
LOW SETTLEABLE SOLIDS REMOVAL EFFICIENCY
Indicators      1.  Floating and gaseous sludges in tanks
                2.  Percent settleable solids removal below 95%
Monitoring,
Analysis
and/or
Inspection
1.  Run settleable solids test (Imhoff Cone)  during times of
    day where there are appreciable changes in plant flow.

2.  Check raw sludge removal pumping cycles and duration of
    pumping period.

3.  Run total solids test on raw sludge removed from tanks
    both at beginning and end of pumping cycle.

4.  Dismantle and/or inspect raw sludge pumps and sludge
    collection mechanism for wear and tear.

5.  Check tank inlets with relation to the tank outlets.  If
    baffles have been installed on the inlets, dewater the
    tanks and check their condition.

6.  Calculate theoretical detention time, weir overflow
    rates, and surface loading rates and compare all data
    with design criteria.
7.  Try a dye test to estimate flow-through time.  Check
    for density stratification due to significant tempera-
    ture or density difference top to bottom.
Corrective      1.  If efficiency of removal drops during peak or increased
Measuresplant flows, the hydraulic capacity of tanks has probably
                    been exceeded.   Refer problem to operating agency
                    engineering staff.
                2.  Repair all worn raw sludge pumps, parts and sludge
                    collector mechanism.

                3.  Damaged or missing inlet line baffles could cause tank
                    short circuiting whereby increased velocities from one
                    end of the tank to the outlet end cause settleable matter
                    to remain in suspension.  Replace or repair baffles.
                                     60

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            II.   PRIMARY TREATMENT - Primary Sedimentation Tanks
Problem
ERRATIC OPERATION OF SLUDGE COLLECTION MECHANISM
Indicators      1.  Frequent replacement of broken sheer pins on chain
                    driven collector mechanisms.
                2.  Frequent torque switch activated alarms on concentric
                    driven clarifier equipment.
                3.  Visible slippage or "stuttering" of clarifier sludge
                    collection mechanisms.
Monitoring,
Analysis
and/or
Inspection
1.  Check all drives for gear wear.
2.  Dewater tank and check chains and sprockets for wear and
    see that chains have not come off sprockets.

3.  Check to see that rags and debris have not entwined
    themselves around sludge collector mechanism.
4.  Check dewatered tanks for excessive bottom deposits of
    sand, rocks and other inorganic material.
5.  Sound bottom for excessive accumulation of sludge.
Corrective
Measures
1.  Repair all worn sludge collector equipment and drives.

2.  If rags are a problem, make provisions for removal of
    all rags and debris as part of the pretreatment process.

3.  If sand and rock deposits on the tank bottom are a
    problem, provide adequate screening and grit removal as
    a part of the pretreatment process.

4.  If sludge accumulation is a problem, increase frequency
    of pumping raw sludge from tanks.
                                      61

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            II.  PRIMARY TREATMENT - Primary Sedimentation Tanks
Problem
LOW SCUM (GREASE)  REMOVAL
Indicators      1.  Visible grease particles being discharges in plant
                    effluent
                2.  Excessive water in scum pits
Monitoring,
Analysis
and/or
Inspection
1.  Run grease test (composite) on plant influent and
    effluent and calculate efficiency of grease removal
    equipment and compare with plant design criteria.

2.  Observe if wooden flights making a return travel on tank
    surface carry grease particles adhered to them under scum
    troughs at the discharge end of the tanks.

3.  Determine, with a pole, the depth of floating scum and
    water in scum pits.

4.  Check capacity of scum pits.

5.  Check for wear of scum pickup wiper blades.
Corrective      1.  If possible, lower return wooden flight to below water
Measures            surface so grease particles do not adhere to them.
                2.  Install water sprays to direct grease particles on tank
                    surface into scum troughs.  Water spray should not break
                    surface tension on water surface.
                3.  If scum removal is done manually and intermittently,
                    continuous removal equipment should be installed.

                4.  Excessive water in scum pits should first be removed by
                    pumping from bottom of pit to plant headworks and then
                    the concentrated scum can be pumped to a digester or an
                    incinerator.
                5.  Efficiency of scum removal in plants receiving a high
                    grease loading can be increased by the addition of
                    flotation or evacuator equipment.

                6.  Since grease particles normally in suspension tend to
                    agglomerate into larger particles after being dosed with
                    chlorine, chlorine contact tanks should be provided with
                    grease removal equipment.
                7.  Pump scum pits down on a regular basis so as not to
                    cause scum overflows back into the clarifier.

                8.  Clean and replace all worn wiper blades.
                                     62

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            II.   PRIMARY TREATMENT - Primary Sedimentation Tanks
Problem
TANK CONTENTS TURN SEPTIC
Indicators      1.   Tank contents are a dark color
                2.   Hydrogen sulfide odors emitted from tanks
 Monitoring,
 Analysis
 and/or
 Inspection
1.  Run total and dissolved sulfide tests on both
    tank  influent and contents.

2.  Run DO test.
3.  Check pH of tank influent.
4.  Check quantity and total  solids of all  inflows  into
    tank  from other plant processes such as digesters
    supernatant, thickener overflows, centrifuge con-
    centrates, etc.
Corrective      1.  If tank influent contains high dissolved and total
Measuressulfides, influent is septic.  Prechlorinate influent or
                    correct problem at source.
                2.  If tank influent pH is below 6 or above 8, toxic waste
                    is being discharged into plant and must be corrected at
                    the source.
                3.  If discharges from other plant processes contain
                    excessive total solids and exceed 5% of the daily tank
                    inflow, the sedimentation tank is being overloaded.  If
                    possible, reduce rate of process flows to sedimentation
                    tanks or pretreat flows by aerating or chlorinating them.
                    If possible divert or find other means of disposal for
                    supernatant or centrates.
                                      63

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             III.  SECONDARY TREATMENT - Activated Sludge Process
Problem
Indicators
               SLUDGE BULKING
                                                                     ., ?
               1.  Rising sludge in final clarifiers
               2.  Floating matter being discharged in final effluent
               3.  Filamentous growths in mixed liquor
Monitoring,
Analysis
and/or
Inspection
1.
2.
4.
5.
                   Check mixed liquor for low pH and low dissolved oxygen.
                   Check sludge age,  food/ micro-organism ratio,  or mean
                   cell residence time.
                   Run  settleability test and check for separation of
                   floe in graduated  cylinder or use Mallory Direct
                   Reading Settleometer.
                   Check aeration period.
                   Check for NO  and NO
                                        .
                                       O
Corrective
Measures
               4.
               5.
               6.
               7.
              10.
                   If possible,  reduce organic loads on aeration
                   tanks affected.
                   Add digested sludge (that has been aerated for some
                   time) to aeration tanks.

                   Dose the aeration tanks with alum or ferric chloride
                   together with lime.
                   Controlled chlorination of return activated sludge.

                   Reduce sludge age and air rate to stop nitrification.

                   Increase sludge  age by regulating waste sludge rate.

                   Increase or correct low dissolved oxygen or pH in
                   aeration tank.

                   Increase aeration period by placing another aerator
                   in operation if  possible or reduce the return sludge
                   rate by thickening the return sludge concentration
                   by coagulation.
                   Control filamentous growth by increasing sludge age
                   or supplementing nutrient deficiencies.

                   If nitrification is desired, maintain a minimum
                   of 3 mg/1 NO  and a maximum of I mg/1 NO .
                               O                           &
                                                                   x
                                                                 -»

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               III.  SECONDARY TREATMENT - Activated Sludge Process
Problem
ERRATIC SLUDGE VOLUME INDEXES
Indicators     1.  Pin floe visible in final clarifiers overflow
               2.  Poor settling characteristics of mixed liquor
Monitoring,
Analysis
and/or
Inspection
1.  Check mixed liquor suspended solids in each aeration
    tank.
2.  Run 30 minutes settleability test in each aeration tank.
3.  Determine whether the point floe is a recurrent
    situation or the result of toxicants.
Corrective     1.  Regulate wasting to decrease suspended solids in
Measures           mixed liquor.
               2.  Chlorinate return activated sludge.
               3.  Decrease solids loading to aeration tanks.
               4.  Make appropriate adjustments to obtain a less
                   oxidized sludge.
                                     65

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            III.  SECONDARY TREATMENT - Activated Sludge Process
Problem
DIFFICULTY IN MAINTAINING BALANCED MIXED LIQUOR AND
DISSOLVED OXYGEN IN AERATION TANK
Indicators      1.  Intermittent sludge bulking

                2.  Loss of sludge blanket in secondary clarifier

                3.  Dark color in the aerator contents
Monitoring,
Analysis
and/or
Inspection
                4.
                5.
    Check D.O.  concentration in different areas of aeration
    tanks during changes in daily flow.

    Check suspended solids in mixed liquor at different
    periods during the day.

    Run suspended solids test on aerator influent and mixed
    liquor to check sludge age.

    Monitor rate of flow to aeration tanks.
    Check daily flow variation in loading for excessive
    peak demand periods.
Corrective      1.  Lower D.O. concentrations occurring during changes in
Measures            plant flow are an indication of excessive loading of
                    aeration tanks.  Increase air supply to tank if possible
                    by placing another blower into service, etc.

                2.  Decrease loading to aeration tanks by placing more tanks
                    into service if possible.
                3.  Provide controlled air supply to aeration tanks by
                    interlocking blower speeds to tank D.O. monitoring
                    equipment.
                4.  Increase inflow could hydraulically overload the
                    secondary treatment system.  If possible, bypass a
                    portion of the flow from the primary sedimentation tank
                    until the flow rate returns to normal.
                                     66

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            III.  SECONDARY TREATMENT - Activated Sludge Process
Problem
EXCESSIVE FOAM IN AERATION TANKS
Indicators
1.  Frothing in aeration tanks
Monitoring,
Analysis
and/or
Inspection
1.  Check influent for radical temperature changes.

2.  Run M.B.A.S. test on influent.

3.  Check suspended solids concentration in aeration tanks.

4.  Check D.O. concentration in aeration tanks.
Corrective      1.  If practical, increase mixed liquor suspended solids by
Measures'            decreasing wasting rate.
                2.  Install or operate reclaimed water sprays in aeration
                    tanks.

                3.  Utilize defearning agent.
                4.  Lower air supply while being careful to maintain a safe
                    dissolved oxygen concentration in aeration tanks.
                                      67

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            III.  SECONDARY TREATMENT - Activated Sludge Process
Problem
DIGESTER SUPERNATANT AND/OR CENTRIFUGE CENTRATE
UPSETTING ACTIVATED SLUDGE PROCESS
Indicators      1.  Mixed liquor changes from a light to a dark brown color

                2.  Mixed liquor suspended solids decrease sharply during
                    operation of centrifuge or when sludge is being pumped
                    to digester

                3.  Final clarifier effluent increases in turbidity

                4.  Mixed liquid DO decreased.
Monitoring,
Analysis
and/or
Inspection
1.  Run total solids and pH tests on supernatant or centrate
    being returned to plant headworks.

2.  Check mixed liquor suspended solids during discharge of
    centrate or supernatant.

3.  Continuously check mixed liquor D.O.

4.  Check volume of concentration of recycle flows
    relative to total plant flow.
Corrective      1.  Program discharges of supernatants or centrates so they
Measures            do not coincide.

                2.  Pump centrates to digester whenever possible.

                3.  If centrates have high solids content, use flocculants
                    in the operation of the centrifuge.

                4.  If supernatant have high solids content, experiment with
                    supernatanting from a different level in the digester.

                5.  If possible, pre-aerate centrate and supernatants prior
                    to discharging them to the activated sludge process.

                6.  Avoid discharging supernatants from septic digesters to
                    activated sludge process.

                7.  If possible, release only small amounts of supernatant
                    or centrate during periods of low inflow and increase
                    return activated sludge rates if necessary.

                8.  Program recycles so that the return load does not
                    exaggerate peak loading.
                                     68

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            III.  SECONDARY TREATMENT - Activated Sludge Process
Problem
UNABLE TO MAINTAIN BALANCED FOOD/MICRO ORGANISM
RATIO IN AERATION UNIT
Indicators      1.  Fluctuation in S.V.I.
                2.  Fluctuation in sludge age.
Monitoring,
Analysis
and/or
Inspection
1.  Check S.V.I, at least daily.
2.  Check mixed liquor suspended solids at least daily.

3.  Check suspended solids in influent and effluent at
    least daily.
4.  Monitor plant flow, return activated sludge rate, and
    waste activated sludge rate.
Corrective      1.  Select and operate secondary treatment system by either
MeasuresMean Cell Residence Time, Solids Retention Time,
                    food/micro organism ratio, or sludge age.
                                     69

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            III.  SECONDARY TREATMENT - Activated Sludge Process
Problem
FACILITIES INADEQUATE FOR DISPOSAL OF WASTE ACTIVATED SLUDGE
(HIGH SUSPENDED SOLIDS IN THE CLARIFIER OVERFLOW)
Indicators      1.  High suspended solids in mixed liquor

                2.  Increased turbidity in final clarifier effluent

                3.  High solids concentration in digester supernatants
                    and sludge thickener effluents
Monitoring,
Analysis
and/or
Inspection
1.  Check S.V.I,  at least daily.

2.  Run C.O.D.  and suspended solids of plant influent with
    and without supernatant and thickener return flows.

3.  Check blanket depth level or high and low load periods.

4.  Check inlet and outlet baffling for possibility of
    short circuiting.
Corrective      1.  If waste activated sludge is not settling in sludge
Measuresthickener, increase flow of raw sludge to thickener or
                    dose thickener inflow with coagulants.
                2.  Attempt to break "sludge cycle" by lowering wasting rate.

                3.  Re-aerate waste sludge prior to pumping to thickeners or
                    discharging to primary clarifiers.

                4.  Change operation mode of aeration tanks to contact
                    stabilization if possible.
                5.  If the sludge doesn't settle satisfactorily, coagulate
                    with iron or aluminum, but adjust pH if necessary to
                    keep aerator pH within 6.0-8.5.
                                     70

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            III.   SECONDARY TREATMENT - Activated Sludge Process
Problem
UNEVEN HYDRAULIC AND SOLIDS LOADING OF AERATION TANKS
Indicators      1.  Mixed liquor suspended solids in each aeration tank
                    varies considerably.
                2.  Dissolved oxygen in each tank varies considerably.
Monitoring,
Analysis
and/or
Inspection
1.  Run S.V.I, in each tank at least daily.
2.  Run mixed liquor suspended solids in each tank at least
    daily.
3.  Run dissolved oxygen in each tank at least daily.
4.  Run suspended solids on influent and effluent.
Corrective      1.  Adjust valves and inlet gates to equalize flow to all
Measurestanks when operating under conventional mode.
                2.  Equalize air flow to all tanks by throttling valves on
                    air discharge lines.
                                     71

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                III.  SECONDARY TREATMENT - Trickling Filters
Problem
ICE BUILDUP ON MEDIA
Indicators
1.  Visible ice formation on filter media
Monitoring,
Analysis
and/or
Inspection
1.  Check air temperature.
2.  Check recirculation rate to filter.
3.  Check flow through filter orifices.
4.  Check temperature of wastewater flow to filter.
5.  Check filter surface for even distribution of flow.
Corrective      1.  By regulating amount of recirculation rate, adjust flow
Measuresto filter to prohibit the formation of ice.
                2.  Adjust flows from orifices and splash plates to reduce
                    spray effects.
                3.  Cover filter to reduce heat losses or install a windbreak
                    to reduce chill factor.
                4.  Manually break up and remove major ice formations.
                5.  If possible, add hot water or steam to filter influent.
                                      72

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                III.  SECONDARY TREATMENT - Trickling Filters
Problem
FILTER ODORS
Indicators      1.  Odors of hydrogen sulfide origin present
                2.  Black slime visible on surface of filter media
Monitoring,
Analysis
and/or
Inspection
1.  Check dissolved and total sulfide of plant and filter
    influents.
2.  Check filter drains for stoppages or growths.
3.  Check rate of recirculation to filter.
4.  Check for filter overflow or splashing.
Corrective      1.  If flow to filter is septic, correct in upstream system
Measuresby aeration or controlled prechlorination.
                2.  Clear under drain system of all stoppages.
                3.  Force air into filter drain system to increase ventilation
                    through filter media.
                4.  Increase recirculation rate to filter to increase D.O.
                    and to slough off surface slime.
                5.  Keep areas around filters clean of slimes and growths.
                6.  Cover filter with inert material and exhaust air into
                    an odor control/scrubber.
                                      73

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                III.  SECONDARY TREATMENT - Trickling Filters
Problem
FLY NUISANCE IN VICINITY OF FILTER
Indicators
    Tiny gnat sized flies becoming a nuisance in plant area
    and in neighboring area
Monitoring,
Analysis
and/or
Inspection
    Inspect grounds for tall grass, weeds and other
    sanctuaries for filter flies.
Corrective      1.  Increase rate of recirculation to filter to wash fly
Measures            larvae out of filter.

                2.  If possible, flood filter for approximately 24 hrs. to
                    prevent completion of life cycle of flies.

                3.  Apply a low dosage of chlorine being careful not to
                    sterilize filter media.

                4.  Maintain grounds so as not to provide sanctuaries for
                    flies.
                                      74

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                III.  SECONDARY TREATMENT - Trickling Filters
Problem
CLOGGING AND PONDING OF FILTER MEDIA
Indicators      1.  Ponding on filter surface
                2.  Intermittent flooding of filter
Monitoring,
Analysis
and/or
Inspection
1.  Check size of filter media for uniformity.
2.  Check for cementing or breaking up of media.
3.  Check for fibers, slime growths, trash, insect larvae,
    or snails in filter media voids.
4.  Check organic loading on filter.
5.  Check hydraulic load on filter.
Corrective      1.  If filter media is non-uniform and the smaller pieces
Measures'            fill the voids, replace the media.
                2.  Jet problem areas in filter media with a high pressure
                    water spray from a stationary distributor.
                3.  Stir media manually to lessen or remove any
                    accumulations.
                4.  Dose the filter media with chlorine at a rate of 5 mg/1
                    for several hours a day during periods of low flow.
                5.  Flood filter media for approximately 24 hours to loosen
                    surface accumulations.
                6.  Dry growth by drying filter for several hours, if
                    possible.
                                      75

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                III.  SECONDARY TREATMENT - Trickling Filters
Problem
CLOGGING OF DISTRIBUTOR NOZZLES CAUSES UNEVEN
DISTRIBUTION OF FLOW ON THE FILTER SURFACE.
Indicators      1.  Uneven sprays from distributor nozzles
                2.  Ponding on certain areas of the filter media with
                    concurrent drying of other areas
Monitoring,
Analysis
and/or
Inspection
1.  Attempt to identify types or solids clogging nozzles.

2.  Check for visible grease particles in waste being
    pumped to filter.
3.  Run settleable solids test of waste being pumped to
    filter.
Corrective      1.  Remove and clean all nozzles and thoroughly flush
Measuresdistributor piping.
                2.  Improve primary clarifier skimming to prevent grease
                    carryover to filter.
                3.  Increase detention time in primary tanks to prevent
                    settleable and suspended solids carryover to filter.
                                      76

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                 III.   SECONDARY TREATMENT - Oxidation Ponds
Problem
EXCESSIVE WEEDS AND TULES
Indicators      1.  Excessive weed and tule growths
                2.  Mosquito problems in neighborhood of ponds

                3.  Poor pond circulation
Monitoring,
Analysis
and/or
Inspection
1.  Check water depths in selected areas of the pond.
Corrective
Measures
1.  Deepen all pond areas shallower than three feet.

2.  Remove all weed and tule growths as soon as they are
    visible.
3.  For mosquito control, vary liquid level in the pond
    every 10 days.
                                      77

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                 III.  SECONDARY TREATMENT - Oxidation Ponds
Problem
POND ODORS
Indicators      1.  Odors of hydrogen sulfide origin from pond
                2.  Other objectionable odors
Monitoring,
Analysis
and/or
Inspection
1.  Check for blue-green algae growths in pond.
2.  Check for scum accumulation in pond.
3.  Analyze for total and dissolved sulfides in pond and
    pond influent.
4.  Check pond pH and pond influent pH.
5.  Check DO content in pond at several locations.
Corrective      1.  If pond influent is septic, correct situation upstream
Measuresby aeration or controlled prechlorination.
                2.  If possible, aerate pond with mechanical aerators.
                3.  Remove or break up all scum accumulations.
                4.  Prechlorinate pond influent.
                5.  If pond is septic, divert flow from aerobic pond to it
                    or pump high D.O. make up water to it.
                6.  Add sodium nitrate to pond.
                7.  Provide odor masking agent if feasible.
                                    78

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                 III.  SECONDARY TREATMENT - Oxidation Ponds
Problem
LOW POND DISSOLVED OXYGEN
Indicators      1.  Low algae growth in pond

                2.  Trace hydrogen sulfide odors

                3.  Grey color of pond
Monitoring,
Analysis
and/or
Inspection
1.  Check all areas in pond lor adequate D.O.

2.  Monitor flow into pond and calculate average daily
    detention time in pond.

3.  Check pH of pond influent and pond contents.

4.  Run total and dissolved sulfides in pond influent.

5.  Check pond loading rate (Ib BOD/acre).

6.  Check for floating aquatic weeds.
Corrective      1.  Increase detention time  in  ponds  to at  least  five days
Measures            by placing ponds in parallel.

                2.  In the absence of adequate  D.O. in the  pond,  aerate pond
                    contents or pond influent.

                3.  Chlorinate pond influent if sulfides are  present.

                4.  Physically remove floating  weeds to increase  light
                    penetration.
                                     79

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               III.  SECONDARY TREATMENT - Final Sedimentation
Problem
                SLUDGE OR PIN FLOC FLOWING OVER WEIRS
Indicators      1.  Particulate material rising to surface in clarifier

                2.  Effluent clarity poor
Monitoring,
Analysis
and/or
Inspection
1.   Check clarity of water in final clarifier with Secchi
    disc.
2.   Measure turbidity of effluent discharged from clarifier
    with turbidimeter.

3.   Attempt to determine height of sludge blanket in
    clarifier with depth sampler and/or a wooden pole.
4.   Run suspended solids test on final clarifier effluent.

5.   Check all sludge uptake piping to see that they are
    flowing freely and that 60% of the sludge removed
    is from inner 50% area of the clarifier.
6.   Check pump rates and schedules of sludge withdrawal
    pumps.

7.   Dewater clarifiers and check for damage on sludge
    scraper  mechanism especially at the periphery of the
    tank.
8.   Determine if the weir overflow rate is equal for
    the entire weir.
Corrective      1.  Increase pumping rate for greater removal of sludge from
Measures            clarifier.
                2.  Wash down or clean all sludge uptake piping.
                3.  Repair or replace all damaged sludge scraper mechanism.

                4.  Level the weir.
                5.  If uneven weir overflow rate is caused from wind,
                    install a windbreak.
                6.  Persistence of this problem would indicate a mal-
                    function in the secondary treatment process.
                                     80

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                III.  SECONDARY TREATMENT - Final Sedimentation
Problem
ERRATIC OPERATION OF SCRAPER MECHANISM
Indicators      1.  Frequent torque switch activated alarms on concentric
                    driven clarifier equipment
                2.  Visible slippage or "stuttering" of clarifier sludge
                    collection mechanisms
Monitoring,
Analysis
and/or
Inspection
1.  Check all drives for gear wear.
2.  Dewater tanks and check for true travel of scrapper
    mechanism.
Corrective
Measures
1.  Repair all worn sludge collector equipment and drives.
                                      81

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      IV.  ADVANCED TREATMENT - Chemical Coagulation and Flocculation
Problem
CHEMICAL COAGULANTS UTILIZED FOR SETTLING OR
DEWATERING SLUDGES THROUGH RECYCLING CAUSE FLOATING
SLUDGES IN PRIMARY SEDIMENTATION TANKS.
Indicators
               2.

               3.
    Floating and gaseous sludge floating in primary
    sedimentation tanks during periods of chemical treatment
    Poor settling characteristics in the sludge
    Poor sludge dewatering characteristics.
Monitoring,
Analysis
and/or
Inspection
1.  Determine types and amounts of chemicals used.
2.  Conduct laboratory jar tests to determine effect of
    recycled chemicals on wastewater.
3.  Check the dosing sequence,  the rapid mix energy, and
    flocculation energy.
Corrective
Measures
    Correct the dosage of coagulants and alkalinity in line
    with process requirements on the basis of phosphorus
    content and a coagulant metal/phosphorus ratio of about
    2/1.  Institute a regular phosphorus determination and
    product turbidity control.
    Correct coagulant concentrations and dose points to
    favor efficient chemical usage.
    Make sure that sufficient rapid mix energy (800-1000 G)
    is applied for 1/2 to 2 minutes after dosage to mix
    substrate and coagulant.  Follow with lower energy
    flocculation to agglomerate fines.

    Adjust coagulant dosage in line with flow and concentra-
    tion variations in the plant inflow.  Monitor the treated
    overflow turbidity by the hour.
                                    82

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                 IV.  ADVANCED TREATMENT - Ammonia Stripping
Problem
FREEZING IN AMMONIA STRIPPING TOWER
Indicators      1.  Ice formation on outside face of tower

                2.  Drop in ammonia removal efficiency
Monitoring,
Analysis
and/or
Inspection
1.  Monitor ammonia removal

2.  Check out water temperature for maximum and minimum
    values.

3.  Check air circulation rate and distribution.
Corrective
Measures
    Use large flow distribution orifices at the outside face
    of the tower thus concentrating a curtain of warm water
    where the cold air first enters the tower.
    Reverse draft fan to blow warm inside air outward to
    melt the ice.
    If ammonia removal efficiency drops below 30%, take the
    tower out of operation.
                                      83

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                 IV.  ADVANCED TREATMENT - Ammonia Stripping
Problem
FORMATION OF CALCIUM CARBONATE SCALE ON AMMONIA STRIPPING
TOWER FILL AND STRUCTURAL MEMBERS
Indicators
1.  Visible scale deposits in tower
Monitoring,
Analysis
and/or
Inspection
1.  Check pH of tower influent  (ph has to be 10.5
    or greater.
Corrective
Measures
1.  Hose off scale with water jet at periodic intervals.
2.  Install water sprays in tower for jetting off scale
    at frequent intervals.

3.  Clean tower with light  solution of sulfuric acid.
                                     84

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                      IV.  ADVANCED TREATMENT - Filters
Problem
FILTER BACKWASH WASH WATER HYDRAULICALLY OVERLOADS AND
UPSETS CLARIFIERS
Indicators      1.  Surging of clarifier during filter backwash operation

                2.  Higher turbidity  in the treated  flow
Monitoring,
Analysis
and/or
Inspection
1.  Determine amount and rate of filter backwash water
    being recycled to clarifiers.
2.  Increase drum speed, backwash pressure or temperature,
    and backwash rate.
Corrective      1.  Collect backwash wastes in a storage tank and recycle
Measures            at a controlled rate to clarifiers.
                                     85

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                    IV.  ADVANCED TREATMENT - Microscreen
Problem
FOULING OF FABRIC WITH GREASE AND SOLIDS
Indicators      1.  Loss of microscreen efficiency
                2.  Visible solids and grease on fabric
Monitoring,
Analysis
and/or
Inspection
1.  Run suspended solids test on influent to screen.
2.  Check for upset in activated sludge process, if any.
Corrective
Measures
1.  Increase speed of drum.
2.  Increase backwashing pressure.
3.  Adjust backwashing cycles.
4.  Backwash with hot water.
5.  Backwash with an approved degreasing agent.
                                     86

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                    IV.  ADVANCED TREATMENT - Microscreen
Problem
MICROSCREEN EFFLUENT EXHIBITS HIGHER SUSPENDED SOLIDS
CONTENT THAN INFLUENT.
Indicators      1.  Increased suspended solids and turbidity on discharge
                    side of screens.
Monitoring,
Analysis
and/or
Inspection
1.  Determine colloidal solids in the influent to
    microscreens.

2.  Determine total solids removal efficiency of
    microscreens.
3.  Determine C.O.D. removal efficiency of microscreen.
Corrective      1.  Convert colloids in microscreen influent to suspended
Measuressolids by adjusting the pH accordingly or by the addition
                    of coagulants.
                                      87

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               IV.  ADVANCED TREATMENT - Activated Carbon
Problem
MECHANICAL FOULING OF COLUMNS
Indicators     1.  The flushing of accumulated solids from carbon columns
                   is followed by an abrupt increase in the rate of
                   absorption
               2.  Pressure rises in downflow columns

               3.  Decrease in flow rate.
Monitoring,
Analysis
and/or
Inspection
1.  Run suspended solids and total organic carbon of
    column influent and effluent.
2.  Check for upset in secondary treatment process.

3   Check columi  operating routine and backwash records.
Corrective     1.  Bypass column influent with large amounts of suspended
Measures           matter.
               2.  Flush columns frequently.

               3.  Consider upflow operation, filtration, or larger
                   carbon grain size.
                                     88

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                       V.  DISINFECTION - Chlorination
Problem
INSUFFICIENT CHLORINE GAS PRESSURE AT THE CHLORINATOR
WITH ALL CYLINDERS CONNECTED TO GAS PHASE
Indicators      1.  Chlorine pressure gage at chlorinator is reading too low.
                2.  Chlorine supply lines from cylinders are either very
                    cold or are icing.
                3.  Chlorine cylinders or cylinder show a frost line.
Monitoring,
Analysis
and/or
Inspection
1.  Reduce feed rate on chlorinator to about one-tenth the
    rotameter capacity.
2.  If after a short period the chlorine gas pressure rises
    appreciably it can be concluded that the rate of feed
    through the chlorinator is greater than the evaporation
    rate of the chlorine cylinders or cylinder at the
    prevailing ambient temperature.
Corrective
Measures
    Connect enough cylinders to the supply system so that
    the chlorine feed rate does not exceed the withdrawal
    rate of the cylinders.  For 150 Ib. cylinders the
    withdrawal rate at room temperature is 40 Ibs. per day
    per cylinder; for ton containers it is 400 Ibs. per day.
    At lower temperature it is less.
    If insufficient cylinder capacity exists, do not try to
    apply heat directly to the cylinders, and do not heat
    the chlorine storage room with a space heater unless the
    control equipment (chlorinator) room can be brought to
    the same temperature.
    The chlorine cylinder should always be kept cooler than
    the control equipment if possible; otherwise
    reliquefaction of chlorine may occur at the chlorinator.
                                      89

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                       V.   DISINFECTION - Chlorination
Problem
INSUFFICIENT CHLORINE GAS PRESSURE AT THE CHLORINATOR
Indicators      1.  Chlorine pressure gage at chlorinator is reading too low.
                2.  Chlorine supply lines from cylinders are either very cold
                    or are icing.
                3.  There is icing or considerable cooling at one point in
                    the chlorine header system between the cylinders and
                    chlorinator.
Monitoring,
Analysis
and/or
Inspection
1.  Reduce feed rate on chlorinator to about one-tenth the
    rotameter capacity.

2.  If icing condition or cooling effect does not disappear,
    mark the point where cooling begins and secure the chlorine
    supply system at the cylinders, but let the chlorinator
    continue to operate.
Corrective      1.  When chlorine gas pressure at chlorinator reaches zero
Measuresand with chlorinator still operating, disconnect flexible
                    connection to one chlorine cylinder.  (This will allow
                    chlorinator to evacuate residual chlorine in header
                    system by replacing chlorine with air.)

                2.  Disassemble chlorine header system at point where cooling
                    began.  A stoppage or a flow restriction will be found
                    at or near this point.
                3.  After the stoppage has  been found it can be cleaned with
                    a solvent such as tri-chlorethylene.

                4.  For massive build-up in black steel pipe header systems,
                    the pickling process should be used.  This consists of
                    isolating the header system by disconnecting it from the
                    cylinders at one end, the chlorinators at the other, and
                    flushing with cold water until the water coming out is
                    clear.  The header then has to be dried with steam or
                    hot air and final air drying to a dew point of -40°F.
                                     90

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                       V.   DISINFECTION - Chlorination
Problem
THERE IS NO CHLORINE GAS PRESSURE AT THE CHLORINATOR,
WHEN APPARENTLY FULL CHLORINE CYLINDERS ARE CONNECTED
TO THE CHLORINE SUPPLY SYSTEM.
Indicators
    Chlorinator gas pressure gage is at zero, inlet valve is
    open, all valves beginning with chlorine cylinder valve
    to the chlorinator are open.
Monitoring,
Analysis
and/or
Inspection
    Check the external chlorine pressure reducing valve
    installed just downstream of the chlorine cylinders.
Corrective      1.  If normal chlorine pressure appears at the chlorinator
Measuressecure all the main chlorine cylinder valves, and start
                    ventilating fans if available and arrange for maximum
                    ventilation.
                2.  Put on a gas mask and gingerly break one flexible
                    connection joint to release the gas in the header system.

                3.  Place a bottle of ammonia on the floor near the
                    connection to be broken and when a white vapor appears
                    leave the area as fast as possible and return only when
                    the vapor disappears.
                4.  Repair the reducing valve which is probably plugged from
                    the inherent impurities in chlorine gas.  These units
                    should be put on bi-annual overhaul.

                5.  Install a chlorine gas pressure gage upstream of the
                    pressure reducing valve.
                                      91

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                       V.  DISINFECTION - Chlorination
Problem
IMPOSSIBLE TO OPERATE CHLORINATOR BECAUSE ROTAMETER TUBE
ICES OVER AND FEED RATE INDICATOR IS EXTREMELY ERRATIC.
CHLORINE SUPPLY IS FROM TON CONTAINERS CONNECTED TO
THE GAS PHASE.
Indicators      1.  There is sufficient chlorine gas pressure and injector
                    vacuum and the chlorine is at room temperature but the
                    rotameter tube that indicates chlorine feed rate is
                    nearly completely iced over.
                2.  The entire chlorine supply line back to the cylinder is
                    also iced over, but cylinders are at about ambient
                    temperature.
Monitoring,
Analysis
and/or
Inspection
1.  Inspect the chlorine cylinder area to see if they are
    connected properly.   (This problem is specific to ton
    containers.)
Corrective      1.  Shut off main outlet valve on all cylinders and evacuate
Measures            chlorine in header system until gage pressure at
                    chlorinator reads zero.
                2.  Disconnect the cylinder that had icing on the flexible
                    connection to the outlet valve and rotate Lt 180° and
                    reconnect to top outlet valve and with- other cylinders
                    closed place this one in operation.
                3.  Tag cylinder so that packager can identify it as
                    defective with possible broken dip tube but allow
                    cylinder to remain in use until empty.
                                     .92-

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                       V.   DISINFECTION - Chlorination
Problem
CHLORINATOR WILL NOT FEED ANY CHLORINE EVEN THOUGH
ALL SYSTEMS APPEAR NORMAL.
Indicators
Monitoring,
Analysis
and/or
Inspection
1.
Chlorinator feed rate indicator shows little or no
indication of chlorine flow when chlorine control valve
is moved from closed to wide open position.
The chlorine pressure gage in the chlorinator is normal
but the injector vacuum gage shows an abnormally high
vacuum.

Check for an obstruction in the chlorine gas line near or
at the inlet cartridge of the chlorine pressure reducing
valve inside the chlorinator by shutting off chlorine
supply system at chlorinator; chlorine pressure gage
remains the same or moves downward in pressure at a very
slow rate, i.e., one division per five minutes.
Corrective      1.  Shut off chlorine supply at the cylinders and try to let
Measuresthe chlorinator drain off all the chlorine gas pressure
                    in the chlorine supply line.
                2.  If this cannot be done, turn on the ventilating equipment
                    in the chlorine container space, if any, open all windows,
                    don a gas mask and break a connection in the chlorine
                    supply header but be absolutely sure that all chlorine
                    cylinders have been secured.

                3.  When the gas has sufficiently cleared itself from the
                    working area, disassemble the chlorinator chlorine
                    pressure reducing valve to remove inlet cartridge and
                    clean stem and seat with a soft cloth.
                4.  If this situation occurs regularly during hot weather,
                    the source of the trouble usually is a result of the
                    chlorine cylinders being hotter than the chlorine control
                    apparatus.
                5.  Inspect cylinder area to see if anything can be done to
                    make the area cooler.
                6.  Do not connect a new cylinder if it has been allowed to
                    sit in the sun.
                7.  Install an external chlorine pressure reducing valve
                    adjacent to the last chlorine cylinder connected to the
                    supply system.
                8.  Precede the reducing valve by a combination chlorine
                    filter and sediment trap.

                                     93

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                       V.   DISINFECTION - Chlorination
Problem
CHLORINE GAS IS LEAKING FROM VENT LINE CONNECTED TO
EXTERNAL CHLORINE PRESSURE REDUCING VALVE (CPRV).
Indicators      1.  There is no visible indication of a malfunction.
                2.  Chlorine escaping from CPRV vent line.
                3.  Chlorine gas pressure, chlorine feed rate and injector
                    vacuum are all normal.
Monitoring,
Analysis
and/or
Inspection
1.  Confirm leak by placing ammonia bottle near the
    termination of the CPRV vent line.
Corrective      1.  The symptom described indicates that the main diaphragm
Measuresof the CPRV has been ruptured.
                2.  Remove the external CPRV after evacuating header system
                    and replace with a jumper tube for temporary operation
                    while valve is being repaired.
                3.  Disassemble valve and replace diaphragm.
                4.  Inspect the ruptured diaphragm to see if failure is from
                    corrosion, improper assembly or just fatigue from length
                    of service.
                5.  Consult manufacturer for expert opinion.
                6.  If failure is from corrosion the chlorine supply system
                    should be inspected for moisture intrusion.
                                     94

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                       V.   DISINFECTION - Chlorination
Problem
INABILITY TO MAINTAIN CHLORINE FEED RATE WITHOUT ICING
OF'CHLORINE SUPPLY SYSTEM BETWEEN EXTERNAL CHLORINE
PRESSURE REDUCING VALVE AND CHLORINATOR.  (EQUIPMENT
CONSISTS OF EVAPORATOR, EXTERNAL CPRV AND THE CHLORINATOR.)
Indicators      1.  Noticeable cooling of gas line to chlorinator beginning
                    at outlet of external chlorine pressure reducing valve.

                2.  Evaporator water bath temperature is normal: 160 to 180°F.

                3.  Further cooling at point of pressure reduction in
                    chlorine pressure reducing valve in chlorinator assembly.

                4.  Deposit of "gunk" on chlorinator feed rate indicator tube
                    and what appears to be droplets of an amber color liquid.
Monitoring,
Analysis
and/or
Inspection
    Reduce feed rate on chlorinator to about 75 percent of
    evaporator capacity.  If this or further reduction of
    feed rate eliminates the above symptoms, the difficulty
    is most likely to be insufficient evaporator capacity.
    If chlorine gas temperature is available, calculate the
    superheat.  If there is less than 5°F of superheat, there
    is very little reserve capacity in the evaporator.  This
    is the result of an accumulation of sludge in the bottom
    of the liquid chlorine vessel of the evaporator.
Corrective
Measures
    Check for stoppage in the external CPRV cartridge if
    superheat cannot be measured.

    Take the evaporator out of the system, flush and clean
    it with cold water and dry it in accordance with the
    manufacturer's instructions utilizing an "Evaporator
    Cleaning Kit."  All evaporators should be routinely
    cleaned after passage of 250 tons of liquid chlorine.
                                      95

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                       V,  DISINFECTION - Chlorination
Problem
CHLORINATION FACILITY CONSISTING OF EVAPORATOR-CHLORINATOR
COMBINATION WITH EXTERNAL CHLORINE PRESSURE REDUCING AND
SHUT-OFF VALVE IS UNABLE TO MAINTAIN WATER-BATH TEMPERATURE
SUFFICIENT TO KEEP EXTERNAL CHLORINE PRESSURE REDUCING
VALVE IN OPEN POSITION.
Indicators      1.  External chlorine pressure reducing valve shuts off
                    intermittently until water bath temperature is raised
                    above 150°F.
                2.  Intermittent  operation of chlorination equipment
                3.  Insufficient  heat being supplied to evaporator water bath.
Monitoring,
Analysis
and/or
Inspection
1.  Check evaporator water bath temperature.
Corrective      1.  After evaporator has been in operation sufficiently long
Measuresenough to bring heating elements to operating temperature,
                    shut down power supply and remove and replace heating
                    elements.
                                     96

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                       V.  DISINFECTION - Chlorination
Problem
INABILITY TO-OBTAIN MAXIMUM FEED RATE FROM CHLORINATOR
OR CHLORINATORS WITH ADEQUATE CHLORINE GAS PRESSURE
AT CHLORINATOR
Indicators
                2.

                3.
    Chlorinator is placed into manual control and control
    valve is opened wide but chlorine feed rate will not go
    beyond 70 to 80 percent of maximum.
    Check injector vacuum gage to see if reading is less
    than minimum recommended by manufacturer.

    Check for injector vacuum reading below ten inches Hg.
Monitoring,
Analysis
and/or
Inspection
1.  Reduce feed rate on chlorinator.

2.  If the injector vacuum reading increases then increase
    the injector water pressure.

3.  Verify whether or not inlet water pressure to the
    injector is the same as when the installation was first
    installed.
4.  Check injector water pump pressure against the
    manufacturer's operating data.
Corrective
Measures
    Disassemble injector and see that the throat and tailway
    are clear and without any abnormal deposition of iron or
    manganese, and clean the injector parts by soaking in
    nuriatic acid, rinse in fresh water and replace.
                                     97

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                       V.   DISINFECTION - Chlorination
Problem
INABILITY TO MAINTAIN ADEQUATE CHLORINE FEED RATE
Indicators
    Inspection of chlorinator reveals that chlorinator cannot
    feed as much as previously noted even though chlorine
    supply pressure is adequate.
Monitoring,
Analysis
and/or
Inspection
    If effluent is used check the injector operating water
    supply for deterioration in supply pump performance.
Corrective      1.  In the case of a centrifugal pump the only solution is
Measuresa complete overhaul.
                2.  If a turbine pump, close down on the needle valve to
                    maintain the proper discharge pressure.
                3.  If the turbine pump has worn sufficiently and it requires
                    operation with the needle valve in the fully closed
                    position, the pump should be thoroughly overhauled.
                                     98

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                       V.   DISINFECTION - Chlorination
Problem
INABILITY TO OBTAIN MAXIMUM OR PROPER FEED RATE FROM
CHLORINATOR WITH ADEQUATE GAS PRESSURE AT CHLORINATOR
Indicators
    With chlorinator in manual control and chlorine control
    valve is manipulated to very the feed rate, the change
    of feed rate response seems sluggish and chlorinator will
    not achieve maximum feed rate.

    The injector vacuum reading is borderline, and when feed
    rate is reduced the injector vacuum does not increase
    appreciably.
Monitoring,
Analysis
and/or
Inspection
    Check the chlorinator vent system for a small vacuum leak
    in the chlorine control apparatus by disconnecting the
    vent line at the chlorinator and while observing the
    chlorinator operation (feed rate and injector vacuum),
    place a hand over the vent connection to the vacuum
    relief device on the chlorinator.  If this action
    produces more injector vacuum and more chlorine feed
    rate, it signifies that air is entering the chlorinator
    via this mechanism (vacuum relief device) because the
    springs have become weak due to normal metal fatigue.

    Moisten all joints subject to a vacuum with ammonia
    solution or put paper impregnated with orthotolidine at
    each of these joints.  With chlorinator operating at
    maximum feed rate, close the injector discharge line as
    rapidly as possible.  If there is a vacuum leak in the
    chlorinator system it will be detected by either the
    ammonia or the paper.
Corrective      1.  If the vacuum leak is in the vacuum relief device,
Measuresdisassemble the mechanism and replace all the springs.
                2.  Repair all other vacuum leaks by tightening a joint,
                    replacing gaskets, replace tubing and/or compression nuts.
                                     99

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                       V.   DISINFECTION - Chlorination
Problem         EXCESSIVE CHLORINE ODOR AT POINT OF APPLICATION
Indicators      1.  Air cover above area of chlorine diffuser reacts with
                    ammonia solution to produce typical white wisps of
                    "smoke" indicating escaping molecular chlorine.
Monitoring,     1.  Scattering ammonia indicator solution onto the wastewater
Analysisstream over the area of the diffuser produces white fumes
and/orat the surface.
Inspection      2^  Cneck chlorine solution strength.


Corrective      1.  Add enough injector water to bring the chlorine solution
Measuresstrength down to 3500 ppm chlorine at maximum expected
                    chlorine feed rate.
                2.  If the chlorine diffuser is situated below the injector
                    which leads to a negative head in the solution line,
                    install a special diaphragm protected chlorine solution
                    pressure gage in the highest point of the chlorine
                    solution discharge line and regulate the injector water
                    flow so that there is a 2 to 3 psi positive pressure at
                    this point.
                                      100

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                       V.  DISINFECTION - Chlorination
Problem
CHLORINATOR WILL NOT FEED ENOUGH CHLORINE TO PRODUCE
A PROPER CHLORINE RESIDUAL AT THE SAMPLING POINT.
Indicators
    A routine spot check sampling s'hows that at some hours
    of the day there is an adequate residual but there are
    times during the day when there is no residual.

    If there is a chlorine residual analyzer the chart will
    show periods during the day of insufficient chlorine
    residual.
Monitoring,
Analysis
and/or
Inspection
1.  Ascertain that if the Chlorination equipment is being
    used for disinfection that it is equipped to proportion
    the chlorine feed rate in accordance with the flow of
    the wastewater.

2.  If it is flow proportional, check to see if the meter
    capacity on the chlorinator matches the plant flow
    meter capacity.

3.  Disconnect the flow proportional control and by manual
    control test the chlorinator to see if it will pull
    maximum feed rate.
4.  Determine if solids have settled to the bottom of the
    contact chamber'.
 Corrective
 Measures-
    The automatic control features of the chlorinator should
    be' repaired by the- manufacturer's field service per-
    sonnel who are equipped to simulate the various t'ypes
    of electric and pneumatic signals commonly used, for
    chlorinator control.

    J-f needed-, clean the chlorine contact chamber..
                                     101

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                       V.  DISINFECTION - Chlorination
Problem
WIDE VARIATION IN CHLORINE RESIDUAL IN EFFLUENT AS
DETERMINED BY HOURLY CHLORINE RESIDUAL DETERMINATIONS
Indicators      1.  Inability to adjust dosage so that there is reasonable
                    agreement of chlorine residual throughout a 24-hour
                    period as determined by occasional chlorine residual
                    analysis at each shift.
Monitoring,
Analysis
and/or
Inspection
1.  While in flow proportional operation the feed rate of the
    chlorinator should be plotted on a piece of graph paper
    against the flow meter reading.  The plots of wastewater
    flow versus chlorine feed rate should yield a straight
    line.
Corrective
Measures
    If the feed rate plots do not follow a reasonably
    straight line, it is well to recheck the zero and span
    of the flow proportional control device on the
    chlorinator.  First make the zero check and then the span
    check in accordance with the manufacturer's instructions.
    If this does not correct the difficulty, it may be
    necessary to replace operating parts within the
    controller to achieve satisfaction.

    If after the flow proportional control system on the
    chlorinator has been corrected the irregular chlorine
    residual reading continues, then it is recommended that
    a continuous chlorine residual analyzer be installed.
                                     102

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                       V.  DISINFECTION - Chlorination
Problem
CHLORINE RESIDUAL ANALYZER RECORDER CONTROLLER DOES
NOT APPEAR TO CONTROL THE CHLORINE RESIDUAL PROPERLY.
Indicators      1.  Recorder draws a poor line on the chart that seems not
                    to bear any relation to the "set point."
Monitoring,
Analysis
and/or
Inspection
1.  First check the loop-time in the system.  This is best
    accomplished by turning off the gas supply to the
    chlorinator and determining the length of time required
    to show a sharp drop in the residual on the analyzer
    chart.
2.  Disconnect the analyzer cell output leads from the cell
    and apply a simulated signal to the recorder mechanism
    from a manually controlled external signal generator.
    (Authorized chlorinator repair personnel carry such a
    device as part of their tool kits.)

3.  Check buffer additive system to see if pH of sample
    going through the cell is maintained at 5 or less.
4.  Check electrode bombardment system and see that
    electrodes are clean, particularly the noble metal
    electrode (Pt. or Au.).  Do not disturb the copper
    electrode unless it is fouled with grease.
5.  If residual analyzer is being used to measure total
    residual, check to see if sufficient potassium iodide
    is being added for the amount of residual being measured.

6.  Reconnect cell output leads and make a zero, span and
    temperature check by following the manufacturer's
    procedure for a routine calibration.
                                      103

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Corrective      1.  If the loop time is found to be in excess of 5 minutes,
Measuressatisfactory operation will not be achieved until the
                    loop time is brought down to 5 minutes or less.  This
                    can be accomplished by moving the injector closer to the
                    point of application,  increasing the velocity in the
                    sample line to the analyzer cell, by moving the cell
                    closer to the sample point, or by moving the sample point
                    closer to the point of application.

                2.  If the line on the chart indicates proper operation when
                    subjected to a simulated signal, this signifies that the
                    equipment between the  cell and the readout of the pen is
                    satisfactory.  The erratic or poor line can either be
                    caused by poor mixing  of chlorine at the point of
                    application or faulty  operation of the cell.  Poor mixing
                    can be verified by setting the chlorine feed rate for a
                    constant dosage (proportional to flow) and analyzing a
                    great many grab samples over a ten minute period as
                    quickly as possible.  A poor mix will show rapid wide
                    swings of the recorder pen.  Consider mixing the point
                    of application and/or  install some type of mixing device
                    to cause turbulence at the point of application.
                3.  If poor mixing is not  the cause, and if the electrodes
                    are clean, and if the  pH and KI additive system is normal,
                    then the difficulty must be in the cell and it should be
                    replaced.

                4.  If when the simulated  signal is applied to the recorder
                    mechanism and the recording system does not respond
                    properly, the difficulty lies in the electrical
                    components of the recorder mechanism.  Authorized service
                    personnel should be summoned to correct the difficulty.
                                     104

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                       V.  DISINFECTION - Chlorination
Problem
CHLORINATION SYSTEM CONSISTS OF EITHER COMPOUND-LOOP
CONTROL OR DIRECT RESIDUAL CONTROL AND SYSTEM DOES
NOT APPEAR TO BE CONTROLLING PROPERLY.
Indicators
    Chlorine residual line on analyzer chart appears normal
    but does not track close enough to set point.
Monitoring,
Analysis
and/or
Inspection
    If the chlorine residual analyzer is operating properly,
    check the chlorinator system to see that it is functioning
    properly over its entire range of feed rate.  Check to
    see if the chlorination system is feeding enough chlorine
    to satisfy the maximum demand; also check to see if the
    rotameter tube range is sized so that incremental
    corrections in feed rate by the residual controller are
    not too large.  These two factors would cause wide swings
    in the chart line, or not allow the chlorine applied to
    ever actually "catch up" with the set point.
Corrective
Measures
    If the chlorination system will not feed enough chlorine,
    consult the corrective measures described previously
    under the problem of chlorination control equipment
    unable to feed enough chlorine.

    If the chlorinator rotameter tube range gives too large
    or too small an incremental change, replace with a proper
    range of feed rate.
                                     105

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                          V.   DISINFECTION - Chlorination
Problem      COLIFORM COUNT DOES NOT MEET THE REQUIRED DISINFECTION
             STANDARDS SET BY REGULATORY AGENCIES.
Indicators   1.
Monitoring,
Analysis
and/or
Inspection
Corrective
Measures
1.
             2.
             3.
Routine analysis of effluent or receiving waters shows
MPN coliform organism to be in excess of that required
by regulatory authorities.

Check capacity of Chlorination equipment as follows:  For
primary effluent chlorinator capacity should be from 175
to 200 Ib per MG.  For secondary effluent 100 to 125 Ib
per MG and for tertiary effluent 75 to 100 Ib per MG
unless nitrogen removal is required.  For the latter or
for those plants requiring free residual chlorine,
equipment capacity must be 10 mg/1 of chlorine for each
mg/1 ammonia nitrogen in the effluent.
All Chlorination equipment used for disinfection of waste-
water effluent should have at the very least control propor-
tional to the effluent flow.  The capacity of the chlorina-
tor should also be based on the maximum reading of the flow
meter.
Continuously record the residual in the effluent with an
amperometric type chlorine residual analyzer.
4.  Check for short circuiting in contact chamber.

1.  Chlorination equipment should be brought up to optimum capac-
    ity requirements.  The necessary equipment should be installed
    to provide flow proportional control.   In plants where only
    an influent meter exists,  it may be required to install an
    effluent meter.  After the proper primary meter is installed
    then the chlorinator can be modified by adding a chlorine ori-
    fice positioner to be operated either electrically or pneu-
    matically from the primary meter.
2.  A chlorine residual analyzer should be installed to properly
    monitor the chlorine control system.  Using this apparatus to
    automatically control the chlorine dosage is optional; how-
    ever, experience shows that the change in chlorine demand of
    most domestic wastewaters is significant enough to warrant
    the small added expense to accomplish automatic dosage control.
3.  Install additional baffling in contact chamber.
4.  If needed, install a mixing device in contact chamber.
                                    106

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                       V.  DISINFECTION - Chlorination
Problem
COLIFORM COUNT DOES NOT MEET THE REQUIRED STANDARDS
FOR DISINFECTION.
Indicators
Monitoring,
Analysis
and/or
Inspection
 Corrective
 Measures
  1.   Routine analysis of effluent or receiving waters shows
      MPN of coliform organisms to be in excess of the
      required standards.

  1.   Check to see if chlorine capacity is adequate, control
      system is functioning properly and effluent is being
      monitored with a continuous chlorine residual analyzer.
  2.   Check the chlorine contact time at low flow, average flow
      and maximum flow to determine the optimum residence time
      of the process.  With this as a basis analyze five
      replicate samples for each hour around the clock on
      Monday, Wednesday, Friday and Sunday for coliform MPN
      after the following treatment:  samples are to be taken
      from the effluent prior to point of application of
      chlorine and dosed in the laboratory with the same amount
      of chlorine as that applied by the chlorination equipment.
      The chlorine for this procedure should be taken from the
      plant chlorine solution line, standardized according to
      Standard Methods and added to one liter replicate sample
      of effluent.  Upon addition the chlorine solution should
      be rapidly and thoroughly mixed, then allowed to stand
      for the amount of time determined previously at the
      optimum residence time.  At the expiration of the
      residence time one portion of the samples should then be
      analyzed for chlorine residual using the iodometric back
      titration procedure while another portion should be
      dechlorinated and analyzed for coliform MPN in accordance
      with Standard Methods.
  3.   If the resulting coliform MPN from the above analysis is
      satisfactory, it is then reasonable to assume that the
      mixing at the point of application is at fault , because
      stirring chlorine in a batch process described above
      results in ideal chemical mixing.
   4.   Check for solids buildup in contact chamber.

   1.   If the difficulty is too low a residual raise feed rate
       and increase contact time if possible.
   2.   If poor mixing is the problem install a mixing device of
       high turbulence such as exists in an hydraulic jump or a
       combination of turbulent flow and mechanical mixer.

   3.   Clean contact chamber to reduce solids buildup.
                                     107

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                       V.  DISINFECTION - Chlorination
Problem
PLANT EFFLUENT DOES NOT MEET TOXICITY REQUIREMENTS
BECAUSE CHLORINE RESIDUAL TO ACHIEVE PROPER
DISINFECTION IS AT TOO HIGH A LEVEL.
Indicators
    Toxicity level is too high as determined by present
    bio-assay procedures.
Monitoring,
Analysis
and/or
Inspection
    Chlorine residual as determined by iodometric method
    using back titration method is deemed toxic to fish and
    other aquatic life in the receiving waters.
Corrective
Measures
1.
Install a dechlorination facility to operate in
conjunction with the chlorination system.
                                     108

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                                VI.   METERING
Problem
PLANT METER UNRELIABLE
Indicators      1.  Drop or sharp increase in totalized dry weather flow
                2.  Overly uniform flow chart
Monitoring,
Analysis
and/or
Inspection
1.  If meter operates on a float, check float well for
    obstructions.
2.  If meter operates on bubbler, check bubbler tube for
    damage.  Also check air pressure gage to see that meter
    is getting proper air flow.

3.  Bypass measuring weir or flume if possible and check
    to see if meter zeros.
4.  Check height of flow over weir or in flume at different
    time intervals and, using the weir or flume characteristics
    formulas, calculate flow and compare with flow meter data.

5.  Compare water surface elevation immediately behind weir
    or flume with elevation of water in float or bubbler well.

6.  Ascertain the fact that none of the plant's process
    return flows (centrate, supernant, waste activated
    sludge, etc.) are discharged upstream from the meter.
7.  Install a portable flow meter in the weir or flume and
    compare results with plant flow.

8.  If metered flow discharges into a wet well or other
    chamber which has a known volume and outflow can be shut
    off, record time of measured rise in chamber and
    calculate inflow rate.  Compare calculated data with
    meter data.
                                     109

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                9.  If wastewater treated at the plant is supplied by one or
                    more utilities and the total amount of water used is
                    metered,  compare area water consumption with plant flow.
                    During fall or early winter months, water consumed is
                    approximately 10% more than wastewater discharged.

               10.  Check magnetic flow meter cores for grease build-up or
                    restrictions.
Corrective      1.  Keep all floats and bubbler wells clean and free of
Measures'            grease by periodic maintenance.

                2.  Differences between inside and outside or bubbler well
                    water surface elevations are due to extreme velocities
                    in the immediate area of these wells.   If possible, move
                    wells to a more quiescent area behind  the weir or flume.

                3.  Clean all foreign matter off weir plates.
                4.  If problem appears to be in the meter, recording or
                    telemetering equipment,  a qualified technician should be
                    called in to repair and  calibrate the  metering equipment.
                                    110

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                  VII.  SOLIDS HANDLING - Sludge Thickeners
Problem
ODOR FROM THICKENER
Indicators      1.  Odors of hydrogen sulfide origin

                2.  Floating or gaseous sludge in thickener

                3.  Corrosion of thickener concrete structure and metal work
Monitoring,
Analysis
and/or
Inspection
1.  Run total and dissolved sulfide test of thickener
    effluent.

2.  Check pumping rate and frequency of pumping raw sludge
    from thickener.

3.  Run total solids test on raw sludge pumped.

4.  Dewater thickener and check operation of a scrapper
    and/or stirrer arms and sludge removal equipment.

5.  Determine sludge blanket depth.
Corrective      1.  Adjust pumping rate to remove solids at a frequent rate
Measures            and at not less than 3% total solids.

                2.  Repair or replace all damaged sludge collector
                    mechanisms.

                3.  Cover thickener and exhaust gases to an odor control
                    scrubber.
                                    Ill

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                  VII.  SOLIDS HANDLING - Sludge Thickeners
Problem
THICKENER CONTENTS DO NOT SETTLE
 Indicators      1.  Floating sludge on thickener surface
                2.  Floe  in thickener effluent

                3.  Increased loadings on primary sedimentation tanks and
                    secondary treatment process
                4.  Excessive sludge solids in the overflow

                5.  Poor  concentration of underflow.
Monitoring,
Analysis
and/or
Inspection
1.

2.

3.


4.
Run total solids on thickener effluent.

Run total solids in raw sludge withdrawn from thickener.

Run total solids of all thickener inflows and compare
to thickener design capacity.

Run 30 minute settleability test of waste activated
sludge inflow to thickener.
Corrective
Measures
1.
                2.
                3.
If thickener effluent contains high solids and the raw
sludge withdrawn low solids , dose thickener with polymers
or other coagulants.

If solids loading exceeds thickener design capacity,
partially bypass thickener, if possible, by pumping raw
sludge from the primary sedimentation tanks directly to
the point of disposal, digester, or incinerator.

If waste activated sludge pumped to thickener does not
readily settle, re-aerate or treat with coagulants.
                                     112

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                    VII.  SOLIDS HANDLING - Sludge Thickeners
Problem
SLUDGE PUMPED FROM THICKENER HAS LOW SOLIDS CONCENTRATION
Indicators
1.  Thin or watery sludge discharged to point of disposal
Monitoring,
Analysis
and/or
Inspection
1.  Run total solids of raw sludge pumped from thickener.
2.  Check pumping cycle and rate of pumping raw sludge
    from thickener.
3.  Check rate of inflow to thickener.
4.  Run total solids of thickener inflow.

5.  Determine depth of the sludge blanket.
Corrective    1.  Adjust pumping rates and cycles, preferably with
Measures          timers, and remove raw sludge from thickener at a density
                  not less than 3% total solids.
              2.  Adjust thickener inflows to apply total solids to
                  thickener of not less than 2%.
              3.  In gravity thickness adjust pumping cycles to
                  maintain 3 to 4 ft sludge blanket.
                                    113

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            VII.  SOLIDS HANDLING - Sludge Digestion (Anaerobic)
Problem
SCUM BLANKET IN TANK
Indicators      1.  Decrease in digester gas production
                2.  Crust visible through sight glasses in digester roof

                3.  Unable to supernate from upper level of digester
Monitoring,
Analysis
and/or
Inspection
1.  Core blanket through digester thief holes to determine
    thickness.

2.  Check digester temperature.
3.  Check daily digester gas production.
4.  Determine gallons of scum pumped to digester daily.
Corrective
Measures
                4.

                5.
    If possible,  recirculate digested sludge from bottom of
    digester to top of scum blanket.

    If digester has a gas mixing system, run system
    continuously while increasing digester temperature to
    not more than 105°F with the incremental increases not
    exceeding 1°F per day.
    If digester has mechanical mixers with draft tubes,
    degassify digester, break up scum with a high pressure
    water jet and direct to draft tubes.

    Clean digester and find alternate means of scum disposal.
    If digester has gas mixer system, place temporary gas
    diffusers in thief holes and pipe compressed digester
    gas to them.
                                     114

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         VII.  SOLIDS HANDLING - Sludge Digestion (Anaerobic)
Problem
NO DIGESTER GAS PRODUCTION
Indicators
Monitoring,
Analysis
and/or
.Inspection
1.  Gas produced has septic odor
2.  Gas produced does not ignite
3.  Increase in digester volatile acids
4.  Increase in volatile acid/alkalinity ratio

1.  Determing digester volatile acid, alkalinity, and pH
    of digested sludge together with trend of volatile
    acid/alkalinity ratio.
2.  Check gas meter and piping for restrictions.
3.  Monitor volume of raw sludge pumped to digester daily.
4.  Determine total solids, volatile solids, and pH of raw
    sludge pumped to digester.
5.  Check digester temperature.
6.  Sound digester to determine depth of scum blanket and
    grit residue on bottom.
7.  Calculate volatile matter reduction in digester.
8.  Check for toxic material in the digester.
Corrective    1.  If volatile acid to alkalinity ratio is greater than
Measures          0.2 and pH below 6.5 add lime to digester to decrease
                  volatile acid/alkalinity ratio and increase pH.
              2.  Do not feed digester raw sludge in low pH ranges  (less
                  than 7.0).
              3.  If volatile reduction  in digester is less than 50%
                  decrease or discontinue feeding digester until pH rises.
              4.  Do not feed digester raw sludge with average volatile
                  solids less than 75%.
              5.  If possible transfer digested sludge with a volatile
                  acid/alkalinity ratio  of 0.2 from another digester to
                  affected digester.
              6.  If scum blanket and/or grit deposits comprise more than
                  50% of the effective volume of the digester, clean the
                  tank.
              7.  Keep digester temperature  at 98 F.
              8.  Clean all restrictions in  gas lines and/or meters.
              9.  If toxic material has  killed digester, clean digester
                  and determine source of toxicity to prevent recurrence.
                                    115

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            VII.  SOLIDS HANDLING - Sludge Digestion (Anaerobic)
Problem
INCREASE IN VOLATILE ACID/ALKALINITY RATIO IN DIGESTER
Indicators      1.  Drop in digester gas production
                2.  Hydrogen sulfide odor from digester supernatant
Monitoring,
Analysis
and/or
Inspection
1.  Determine volatile acid, alkalinity and pH of digested
    sludge at least twice daily.
2.  Check digester temperature.

3.  Check pH of raw sludge pumped to digester.

4.  Check mixing in digester.
Corrective
Measures
1.  If digester pH is below 6.5, add lime to digester.

2.  If volatile acid/alkalinity ratio is greater than 0.4
    decrease or discontinue feeding digester and add lime.

3.  Do not feed digester raw sludges with pHs lower than 6.8.
4.  Do not let digester temperatures drop below 90°F.
5.  If possible, transfer sludge with low volatile acid/
    alkalinity ratio content from another digester to
    affected digester.

6.  Keep contents of digester well mixed.

7.  Decrease sludge withdrawal rates from digester.
                                     116

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            VII.  SOLIDS HANDLING - Sludge Digestion (Anaerobic)
Problem
FOAM IN DIGESTER
Indicators      1.  Foam discharged from upper level supernatant lines
                2.  Froth visible through sight glasses in digester roof
Monitoring,
Analysis
and/or
Inspection
1.  Determine total and volatile solids of sludge being
    pumped to digester and volume pumped.
2.  Determine pH of digester contents.
3.  Check digester temperature daily.
4.  Monitor withdrawal rate of sludge from digester.
5.  Ascertain depth and/or thicknesses of grit deposits
    and/or scum layers.
6.  Check digester mixing program and effectiveness of
    mixing equipment.
Corrective      1.  Maintain digester pH between 6.8 and 7.2 and volatile
Measures            acid/alkalinity ratio below 0.2 by adding lime.
                2.  Reduce or discontinue pumping raw sludge to digester.
                3.  Maintain digester temperature constant and at least
                    at 95°F.
                4.  Attempt to thoroughly mix digester by recirculation or
                    by available digester mixing equipment.
                5.  Break up scum layers or, if not possible, clean digester.
                6.  If possible, add digested sludge from a healthy digester.
                                     117

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            VII.  SOLIDS HANDLING - Sludge Digestion (Anaerobic)
Problem
LOW REDUCTION OF VOLATILE SOLIDS IN DIGESTER
Indicators
1.  Volatile reduction calculates to less than 50%
Monitoring,
Analysis
and/or
Inspection
1.  Determine total solids of digested sludge and/or raw
    sludge being pumped to digester.
2.  Monitor solids loading to digester daily.
3.  Monitor solids withdrawal from digester.
4.  Check total solids in digester supernatant.
5.  Ascertain depths and/or thickness of grit deposits
    and/or scum layers.
6.  Determine volatile acid/alkalinity ratio  and pH of
    digested sludge.
7.  Monitor digester gas production.
Corrective      1.  If total or volatile solids daily loading of digester
Measures            exceeds design loading, reduce the amount of sludge
                    pumped to the digester daily.
                2.  Keep digester temperature above 95°F.
                3.  Raw sludge pumped to digester should contain more than
                    50% volatile solids.
                4.  Recirculate and mix digester.
                5.  Prolong periods of withdrawing digested sludge until
                    volatile reduction is above 50%..
                6.  Lower volatile acid/alkalinity ratio and raise pH above
                    6.5 by adding lime to digester.
                7.  If supernatant contains high solids content, let
                    digester settle.
                                     118

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            VII.  SOLIDS HANDLING - Sludge Digestion (Anaerobic)
Problem
HIGH PERCENT SOLIDS IN DIGESTER SUPERNATANT
Indicators      1.  Supernatant very dark and thick

                2.  If supernatant is circulated to plant headworks,  primary
                    and/or secondary treatment processes efficiency drops
                    severely.
Monitoring,
Analysis
and/or
Inspection
1.  Determine total solids of digester supernatant while
    supernating from different levels in the digester.

2.  Determine total solids of digested sludge.
3.  Monitor amount of raw sludge, activated sludge, and scum
    pumped to the digester daily.

4.  Check pH of digester supernatant.
5.  Determine length of time of digester mixing.
Corrective      1.  If supernatant contains more than 1% solids, do not mix
Measures            digester and feed alternate digester if possible.
                2.  Supernate from digester level which gives the least
                    solids in the supernatant.
                3.  Supernate from one digester into another if possible.
                                     119

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                    VII.  SOLIDS HANDLING - Centrifuging
Problem
LOW SOLIDS RECOVERING RATE
Indicators      1.  Centrifuge efficiency falls below 60%

                2.  Solids in centrate exceed 3%.
                3.  Centrate very dark in color.

                4.  If centrate is recirculated to the plant headworks, the
                    efficiency of primary and secondary treatment processes
                    are directly affected.
                5.  Cake appears thick and quite wet.
Monitoring,
Analysis
and/or
Inspection
1.  Calculate centrifuge efficiency.

2.  Monitor sludge feed rate to centrifuge and percent
    solids in sludge.
3.  Monitor coagulant, if any, feed rate to centrifuge.
4.  Check centrifuge for mechanical wear.

5.  Check pool depth.
Corrective
Measures
1.  Decrease sludge feed rate to centrifuge.
2.  Increase chemical coagulant dosage, if any.

3.  Repair or replace all worn centrifuge parts,
4.  Increase pool volume and bowl speed.

5.  Reduce conveyor speed.
                                     120

-------
                ••.  .VII.  SOLIDS HANDLING -  Vacuum  Filters
Problem.
LOW SOLIDS  RECOVERY
Indicator       1.  High solids  in  filtrate
                2.  Poor clarity  filtrate
Monitoring,
Analysis
and/or
Inspection
1.  Calculate  filter efficiency.
2.  Monitor  coagulant,   if  any,  feed.
3.  Check  filter mesh for blindings or coarseness.
Corrective
Measures
 I-.--.-•.Increase  chemical  coagulant feed rate.
 2. ..Clean filter media.
 3."  Install  fine mesh  filter media.
 4. -Check sludge washing (elutriation) process.
 5.   Check filter drum  speed and operation cycle.
,6.  .Change, types of  coagulants being used.
                                     121

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                    VII.  SOLIDS HANDLING - Incineration
Problem
ABNORMALLY HIGH TEMPERATURE IN FURNACE
Indicators      1.  Temperature indicator exceeds limit of maximum operating
                    temperature.
                2.  High temperature alarm activated.
Monitoring,
Analysis
and/or
Inspection
1.  Check rate of fuel consumption to determine if excessive.

2.  Check to determine if fuel feed is off and temperature
    is still rising.  Greasy solids may be present.

3.  Check temperature indicator to see if it reads all the
    way up on the scale.
Corrective
Measures
    Decrease fuel feed rate, if excessive, in relation to
    sludge feed rate.
    If temperature rises without supplementary fuel feed,
    greasy solids may be present in sludge.  (This occurs
    infrequently when 100% primary sludge is incinerated.)
    To lower temperature, raise air feed rate while holding
    sludge feed rate constant.  If air feed rate is at
    maximum, reduce sludge feed rate slightly.
    If temperature indicator is all the way up the scale,
    this is an indication that the termocouple well is burned
    out.  Replace thermocouple with spare unit, repair or
    replace thermowell with spare.
                                     122

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                    VII.  SOLIDS HANDLING - Incineration
Problem
ABNORMALLY LOW TEMPERATURE IN FURNACE
Indicators      1.  Temperature indicator shows low on scale.
Monitoring,
Analysis
and/or
Inspection
1.  Check calorific value of sludge to determine if it is
    decreasing.
2.  Check moisture content of sludge to determine if it is
    increasing.
3.  Determine level of excess oxygen in stack.
Corrective
Measures
    If calorific value of sludge is low, or if sludge moisture
    content is high, increase the supplementary fuel feed
    rate.
    If excess oxygen is abnormally high in stack exhaust,
    reduce the air feed rate slightly or increase sludge
    feed rate.
                                     123

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                    VII.  SOLIDS HANDLING - Incineration
Problem         HIGH OXYGEN LEVEL IN FURNACE STACK EXHAUST
Indicators      1.  Oxygen analyzer (recorder chart) indicates excessive
                    oxygen in stack exhaust
Monitoring,     1.  Determine total and volatile solids of sludge fed to-
Analysis            furnace.

	          2.  Check to determine if sludge is being fed to incinerator.
Inspection
Corrective      1.  If sludge being fed to furnace is low in solids, increase
Measures            the speed of sludge pump which feeds centrifuge.  If the
                    air feed rate is low and the sludge rate at a maximum
                    and the exhaust oxygen is still high, shut down.- The
                    sludge supply to the furnace is inadequate.'
                2.  If sludge is not being fed to incinerator, check -'for
                    blockage of sludge in feed chute and check sludge'feed
                    pump stator.  Unplug chute or repair statorTif not in
                    good condition.
                                     124

-------
                    VII.  SOLIDS HANDLING - Incineration
Problem
LOW OXYGEN LEVEL IN FURNACE STACK EXHAUST
Indicators      1.  Oxygen analyzer (recorder chart) indicates low oxygen
                    in stack exhaust.
Monitoring,
Analysis
and/or
Inspection
1.  Check volatile content of sludge fed to furnace to
    determine if increasing.
2.  Check sludge for grease content to determine if
    increasing.
3.  Check to determine if air flow to furnace is restricted.
Corrective      1.  If the volatile content of the sludge is increasing or
Measures            if the grease content of the sludge is increasing,
                    increase the air feed rate.  If the air feed rate is at
                    maximum decrease sludge feed rate.
                2.  Remove any restrictions or blockages in air conduits.
                                     125

-------
                  VII.  SOLIDS HANDLING - Sludge Lagooning
Problem
EXCESSIVE SOLIDS CARRIED OVER FROM LAGOON
SUPERNATANT TO PLANT INFLUENT
Indicators      1.  Dark supernatant discharged from sludge lagoons

                2.  Solids removal efficiency of plant treatment processes
                    is lowered.
Monitoring,
Analysis
and/or
Inspection
1.  Determine total and suspended solids of lagoon
    supernatant.
2.  Measure depth of sludge in lagoons,
3.  Check for broken dikes between lagoons.

4.  Check rate and volume of application of digested sludge
    to lagoons.

5.  Determine total solids of sludge being applied to
    lagoons.
Corrective      1.  Reduce volume of sludge applied to lagoons thereby
Measures            reducing depth of sludge in lagoon.

                2.  Repair all broken dikes between lagoons.
                3.  Delay release from lagoons of supernatant with heavy
                    solids content until sludge is allowed to settle.
                                     126

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                  VII. SOLIDS HANDLING - Sludge Lagooning
Problem
ODORS FROM SLUDGE LAGOONS
Indicators
1.  Obnoxious odors from sludge lagoons.
Monitoring,
Analysis
and/or
Inspection
1.  Determine volatile acid/alkalinity ratio and pH of
    digested sludge being applied to lagoons.
2.  Determine total and dissolved sulfide of lagoon
    supernatant.
Corrective      1.  If volatile acid/alkalinity and pH tests indicate a sour
Measures            digester, attempt to correct problem at source.
                2.  Apply lime to surface of lagoon.
                3.  Install peripheral odor control system.
                4.  Flood lagoon with heavy chlorinated water.
                                     127

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CLASSIFICATION  OF
WASTEWATER
TREATMENT   PLANTS

-------
                                   Appendix A

                 CLASSIFICATION OF WASTEWATER TREATMENT PLANTS
      This section of the manual contains information for the classification
and identification of wastewater treatment plants by various designations.
These include:
           • Definitions of the classes of plants by function

           • Operator classification
           • Geographic location and climatic conditions

           • Common processes and operational units
      Also included is a matrix by which treatment systems are clas-
sified by their unit operations , removal efficiencies and expected
effluent quality.
      This section is used by:
           • Isolating treatment system (by various classification)

           • Determining the units which fall into that general system
           • Learning the performance capabilities of the system.
      This information, along with operational data for the particular
system from Section II of this manual, is compared to the performance and
operational data of the plant being evaluated and is to be considered in
the overall evaluation of the plant.

CLASSIFICATION BY FUNCTION
      Following are generalized definitions of classes of treatment plants
according to their functions:
      1.  Primary treatment - Those wastewater treatment plants that employ
          methods which remove or 'reduce a high percentage of the suspended
          and floating solids but little or no colloidal and dissolved matter.

      2.  Secondary treatment- Those methods which remove or reduce fine
          suspended colloidal, dissolved solids, and cause the reduction
          of organic material by biological oxidation.
      3.  Advanced waste treatment - Those methods which remove or reduce
          nutrients, residual organics, residual solids and pathogens by,
          but not limited to, sand filtration,chemical treatment, carbon
          absorption, ammonia stripping, electrodialysis or reverse osmosis.
                                      A-l

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OPERATOR CLASSIFICATION

      The classification system used in the area of the plant being evaluated
should be reviewed to see if the proper personnel are being utilized for the
existing treatment system.

      Table A-l shows the diversification of wastewater treatment plant
classifications as denoted by their type, design flow and population served,
contrasted with the class of operator which should be capable of operating
them.  These classifications have been established by the California Water
Pollution Control Association and the California State Water Resources
Board.  Evaluators should be aware that most states will have their own
classification system.
                                    Table A-l

                  OPERATOR AND TREATMENT PLANT CLASSIFICATION
 California Water     California*
 Pollution Control     Operator      Treatment Process
    Association     Classifications
Design Flow  Population
   (MOD)      Served
IV

III
II
I

la

I Stabilization Pond
Primary
II Primary
Biofiltration
III Primary
Biofiltration
Activated Sludge
Tertiary
IV Primary
Biofiltration
Activated Sludge
Tertiary
V Biofiltration
Activated Sludge
Tertiary
All 2000
1 or less
1-5 2000 to
1 or less 10,000
5-20 10,000 to
1-10 40,000
5 or less
1 or less
20 & over 40,000
10-30
5-20
1-10
30 & over
20 & over
10 & over
      Classification adopted by the State Water Resources Control Board
                                     A-2

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      Temperature zones and their approximate sphere  of influence ,  along with
probable effects on operating efficiencies,  are defined below.

      1.  Cold Zone - average January air temperature of 30  F or less
          will cause a decrease from 4 to 5  percent in operating efficiency
      2.  Temperate Zone. - average January air temperature of 35 to 45  F
          will cause a decrease of 4 to 5 percent at  the 35  F range but
          normal operation at the higher temperature
      3.  Warm Zone - average January air temperature of 50  to  70 F allows
          normal operation at the low temperature and a. possible 4  to 5
          percent increase in- efficiency at  the higher range.

The following sketch delineates the.approximate climate zones in the-United
States..
      Alaska
     Hawaii
temperate zone
                        LOCATI ON OFiitMPE KATU RE. ZONES:
                        1N THE<;UJ
-------
DDE
COMMON PROCESSES AND OPERATIONAL UNITS
      The purpose of this subsection will be to identify all of the opera-
tional units and processes common to wastewater treatment plants operating
in the primary, secondary and advanced waste treatment mode.

      While every treatment plant can be considered unique, it is obvious
that most treatment plants will have many operations and processes in com-
mon.  Below is a list of the most common units used in various treatment
modes.
      Pretreatment
      To remove or reduce floating solids and coarse suspended solids, use:
             Racks
             Medium screens
             Grit chambers
             Skimming tanks
      Primary Treatment

      To remove or reduce fine suspended solids, use:

             Fine screens
             Sedimentation
             a.   Plain sedimentation tanks, with or without
                  mechanical sludge-removal devices
             b.   Septic tanks (biological action also takes place)
             c.   Imhoff tanks (biological action also takes place)
             d.   Chemical precipitation tanks
      Secondary Treatment

      To remove or reduce suspended colloidal and dissolved solids ,
      oxidize with
             Filters - intermittent sand filters
                       contact filters
                       trickling filters
             Aeration - activated sludge
                        contact aerators (as used in aerated lagoons)
             Chlorination
             Oxidation ponds
      Disinfection
            Chlorination
            Ozone

      Advanced Waste Treatment
            Chemical/physical treatment methods
            Carbon absorption
            Ammonia stripping
            Electrodialysis
            Reverse osmosis or desalting
            Microscreening


                                      A-4

-------
Ultimate Wastewater Disposal

      Discharge into receiving waters
      Irrigation or disposal on land by
      a.   Application to surface
      b.   Subsurface irrigation
      c.   Groundwater recharge
      Treat by advanced treatment system and reuse for
      industrial water supply or possibly a fire protec-
      tion system
Treatment and Disposal of Wastewater Solids

      Screenings
      a.  Treatment
          (1)  Medium - shred and digest
          (2)  Fine -  digest
      b.  Disposal
          (1)  Medium - burial or incineration
          (2)  Fine - burial or incineration
      Settled Solids (sludges)

      a.  Treatment
          (1)  Sludges from primary and secondary
               treatment by:
               (a) Digestion
               (b) Thickening (by gravity or flotation; may or
                   may not be conditioned by elutriation or
                   chemicals)
                   1) Vacuum filtration
                   2) Drying on beds or in kilns
                   3) Centrifugation
      b.  Disposal
          (1) Wet sludges - dumping at sea or piping to sea
                            (where still permitted)
          (2) Dried or dewatered sludges - incineration or use
              as soil conditioner or deposit in a landfill
                                A-5

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Performance of Treatment Systems

     Table A-2 is a classification matrix of treatment systems by their unit
operations, removal efficiencies and expected effluent quality.  It indicates
the percentage removal of constituents (based on process effluent .to process
influent) and ranges of effluents of treatment systems which are employed
in the wastewater treatment.  Most of the systems shown have some form of
pretreatment, in combination with primary, secondary or advanced, unit
operation which would provide the influent quality that can be handled by
the treatment system.  In order for plants to approach the effluent ranges
indicated, each unit operation would have to be examined and evaluated to
determine what operation could be improved without affecting other plant
operations.
                                       .A-6

-------
Rocks or Bar Screens c
Z
Medium Screens I;
Grit Chambers °
Aeration I >
PrcVFrntl Qrlarlnotion w O
Fir. Serins ® "
Chemical Precipitation
Primary Sedimentation






.-

















••—
8y AMBani.1 stripping rawer


Biological Treatment JS
o
Final Clarification Z
Chlorination 3
••


























Physical-Chemical
Sand Filtration >
5
Carbon Adsorption £
s
Sludge Treatment & Disposal












^-





TREATMENT SYSTEM
PRIMARY TREATMENT
ACTIVATED SLUDGE
. Conventional
. Contact Stabilization
. Completely Mixed
. Two Stage Activated Sludge
TRICKLING FILTERS
. Low Rate
. High Rate
STABILIZATION PONDS
PACKAGE AERATION PLANTS
ADVANCED WASTE TREATMENT
. Reverse Osmosis
. Activated Carbon
, Microicreening
. Daep Bed Sand Filtration
(Rapid sand filtration)
. Phosphorous Removal
(Chemical treatment)
. Ammonia Stripping ©
. Elactrodialyih
EFF
15-65

80-95
10-30
85-95
10-25
80-95
10-20
90-96
5-20

85-88
25-30
80-85
70-100

88-99.5
4-22

90
90
30-70
50-70
35-65

<10
UENT
NOTE:
top nim
§












90-98
95




<10
CONS
Data in
t*»rs In
1
1
•5
Z












70





TITUE
each to
*, hot
.5
S












60-55



00-95

* -
.on in n
1
Z
i
1












50-00




<5
7/1
i
s












90-99
0.5


70-85
2-4

<5
Suspended Solids
«-75






05-90
20- 30
60-80
80-100

74-94
17-29

100
60-80
< 7
20-80
3-5
60-85

(1













100
90





i












60-100
80





.2
i


















SECTKW
Background
Ops fiat*
Probletm
L-l to C-ll
11-19
IV 43-63
D-7 to 0-9
11-22
IV 64-71




D-S to D-6
11-21
IV 72-76


D-9 to P-1J
II- 21
IV 77-79
P 13~14
11-21
E-l to f-S
11-24
VI 82-11






  A function of pH and temperature

®Not all operations are uwd in all plants
^In color units

-'All percent removals are based on process effluent to process influent
                                                                        Table A-2

                                                                        Classification Matrix  of Treatment  Systems
                                                                        by  Their Unit Operations,  Removal Efficiencies
                                                                        and Effluent  Quality
                                                                                                                    A-7

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B

-------
PERSONNEL

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                                   Appendix B
                             PERSONNEL REQUIREMENTS
     This section of the manual contains information on personnel require-
ments for effective treatment plant operation.  It lists the minimum skills
required for the various duties which are performed at treatment plants.
A manpower and work schedule is included to delineate the numbers of per-
sonnel and hours needed to perform the required work.
     Table A-l (Appendix A) of this manual indicates the classification of
operator for plant size and treatment system.  This data, along with the
information presented in this section, should be compared against personnel
information for the plant being evaluated to see if adequate staff (both in
numbers and qualifications) is being utilized.  This should be included in
the overall evaluation rating given to the plant.

GENERAL SKILLS
     The skill requirements outlined below are minimal for successful per-
formance of specific required duties.  These are only a guide; additional
requirements for the particular plant location should be checked.
       •  Supervisory Personnel  (level of ability depends on size and
          type of plant) - high school education or equivalent , should
          display better than average ability to:
               1.  Use and manipulate basic arithmetic and geometry.

               2.  Think in terms of general chemistry and physical
                   sciences.
               3.  Understand biological and biochemical actions.
               4.  Grasp meaning of written communications.
               5.  Express thoughts clearly and effectively, both
                   verbally and in writing.

     In addition, supervisory personnel are often responsible for:
               1.  Public relations

               2.  Bookkeeping

               3.  Analysis and presentation of data
               4.  Budget requests

               5.  Report writing
               6.  Personnel
                                      B-l

-------
               7.  Safety educational program
               8.  Contracts, specifications and codes
               9.  Estimates and costs

              10.  Plant library


        « Laboratory Technicians - require training in laboratory pro-
          cedures and mathematics

        • Operating Personnel - require training in:

               1.   Fundamentals of wastewater treatment processes,
                    including chemistry and biology.

               2.   Mathematics (including geometry).
        • Maintenance Personnel - must be familiar with and capable of:
               1.   Mechanical repairs

               2.   Electrical and electronic repairs.

MANPOWER AND WORK SCHEDULING

        • Day-Shift Operators.   225 days/year at 6 hours/day = 1,350 hours/
          year.  Attempts to schedule workloads and staff plants on this
          basis indicates that 5-1/2 hours/day is more realistic.  This
          value will drop as the number of phone calls, visitors, inspectors ,
          and emergencies increase.

        • Night-Shift Operators.  7 hours/man/shift (fewer interruptions
          and work is of the routine inspection and recording nature).

     Table B-l shows ranges of the number of personnel which would be re-
quired to operate various modes of treatment systems.  Each plant may have
its own particular operating mode, depending on the number of components
which make up liquid and sludge treatment, along with administrative and
general plant functions.  The advanced waste treatment plants were not
included in this table because of the lack of reliable manpower estimates
for this classification.
                                     B-2

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                                           Table B-l
                              PLANT MANPOWER REQUIREMENTS*
Type of Plant                                   Average Capacity  (MGD)
                       13         5       10       20      35     50     65     80      100

Primary              4.5-6  6.5-7.5    7.5-9     10-13  15.5-19  22-27  29-34  34-41  40-49  50-59

Secondary  (including   6-7   7.5-9.5    9.5-11.5  13-16  19.5-24  28-34  37-44  45-53  53-61  63.5-76.5
Trickling  Filter)

Secondary  (including   7-8   9.5-10.5   11.5-13   15-18   23-26  33-38  43-49  51-59  61-69    71-82
Activated  Sludge)



      *Based on  a preliminary study performed by Black and Veatch  for the EPA.
                                               B-3

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-------
PRIMARY
TREATMENT MODE
(Background Info)

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      7046
                                 Appendix C

                          PRIMARY TREATMENT MODE
                         (Background Information)
     This section of the manual contains background information on processes
generally used in preliminary and primary treatment of wastewater.  It
describes the basic mechanisms.of the various processes and how they fit
into the overall treatment scheme.  A list of references for each process
is included for additional information.

     The tables located in Section II of this manual list the common
preliminary and primary treatment operating parameters, loading rates,
material accumulated during process operation, and support systems which are
used in conjunction with each process.  If a general review of preliminary
and/or primary treatment is desired , review this section plus the applicable
tables in Section II,  and the pertinent  problems and solutions in Section IV.
GENERAL

     Pretreatment of raw wastewater includes the removal of large pieces of
debris by passing it through a bar screen to remove large solids and then a
grinder (comminution) to reduce particle size of the remaining solids to
protect plant equipment and prevent plugging of pipes.   This treatment also
includes degritting by sedimentation.  After degritting, the wastewater goes
to the primary treatment where a sedimentation process  removes a portion of
the suspended solids (SS) and the settleable solids, along with related
biochemical oxygen demand (BOD).

     Figure C-l shows a pre- and primary treatment system.  There are many
configurations that can be representative of this form  of treatment, with
units being added or deleted on the basis of the degree of treatment
required, economics and space availability.

     References shown after each description of a process provide additional
information on that particular process.
                                     C-l

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        7046
           If no cutters
           or shredders
           screenings
              XX
Hauled to
sanitary landfill
or incinerator
' Chemical addition
I        ...     I
i for precipitation   |
                         Influent  \   From combined system
                                      or sanitary system
                                    	By Pass
                                  Prechlorination wet well
                                   Weir for flow control
                            CUTTERS
                            SHREDDERS
                            COMMINUTOR
                         n
                           PP.EA.EPATION    h
                           CONTROL
                            FINE SCREENS
                        .
                   .     fo SE
                        H
                          '
         DIMENTATION
LAGOONS


_&. VACUUM
" \FILTF R>
                         sludge
> DIGESTER
                               CHLORINATION &
                               CONTACT CHAMBER
                             1
Secondary system
                                                   Effluent
                                                   discharge
                                                                                    Periodically
                                                                                    scraped,
                                                                                    hauled
                                                                                    Hauled or
                                                                                    incinerated
                                                                              Discharge
                       Fig. C-l.   A Primary Treatment  System
                                             C-2

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      7046
PRETREATMENT


Flow Regulators

     Local conditions will determine the hourly variations in quantity and
strength of the wastewater.  The regulation and metering of flow through the
treatment plant is accomplished by use of weirs and flumes for open channel
sections, and the venturi tube, orifice plate, Dahl flow tube and magnetic
flow meter for pipe flows.

     Devices which measure flow in an open channel all operate with a head
loss.  The parashall flume has the smallest head loss of all the commonly
used open channel flow meters and is the one commonly used.  Some plants
utilize electronic sensors coupled with servo control units that operate
valves or other mechanisms for flow control or diversion to various parallel
units.
Racks and Screening Devices

     Racks and screens are designed to remove floating matter and larger
suspended solids  (mainly inorganic).  Commonly used screening systems include
racks,  coarse or medium,  having either:
          1.   Fixed bars,  either hand or mechanically cleaned,  or
          2.   Movable racks,  such as the cage rack.
                                                              / —
                                                             /  //I  / trough
          a)  Fixed Bar Rack                 b)  Mechanically Cleaned Rack
                          Fig.  C-2.   Fixed  Bar Racks
                                     C-3

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      7046
     Figure C-2a shows a cross-section of a  fixed medium bar rack.  This  rack,
like the coarse rack, is primarily used to protect pumps.   The medium rack
also removes floating material which will form a heavy and troublesome scum
in sedimentation basins.
                                            For additional information see:
                                            Chapter 4 of ASCE Sewage Treatment
                                            Plant Design and Chapter 22 of
                                            Water Supply and Sewage-Steel.
Grit Chambers

     Grit chambers are installed prior to sedimentation and usually after
bar racks to remove dense mineral matter such as sand,  gravel,  egg shells
or cinders.  Grit removal helps prevent problems in pumping sludge.  Grit
chambers are also used to avoid the cementing effects on the bottom of the
sludge digester and in the sludge blanket of the primary settling tank.
They also are installed to prevent reduction of active  digester capacity
and help prevent damage to mechanical equipment.  These units are usually
installed in plants with combined flow; however, many of the newer plants
are designed with grit removal systems as common practice.   Figure C-3 shows
a plan and a section view of the most common configuration of a grit chamber.
                 PLAN
                                                       weir
              SECTION     —*-  flow
                        _^^-^^,       Snt
                         Fig. C-3.  Grit Chamber
                                     C-4

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      7046
Removal mechanisms generally  fall into one of four types:

        1.  Flow rate  control which  is maintained at 0.75 to 1.0  ft/sec
            by proportional weirs, by controlling the depth of  flow.

        2.  Clarifier-like mechanisms, sized to cause grit to fall out.
            The grit is then  cleaned by washing and the organics  are
            returned to the wastewater flow.

        3.  Hydraulic  cyclone, removes grit by centrifugal force  which
            tends to force the heavier grit particles to the outside
            of rotating flow  stream.
        4.  Injection  of diffused air produces a spiral flow velocity
            causing particles to settle out.

The  average cleaning interval is every two weeks.  In wet weather, and
particularly with combined wastewater flow, the accumulation of grit may be
enormously increased,  necessitating  rapid or continuous cleaning  to keep the
unit operating efficiently.
                                            For additional information see:
                                            Ch. 23 of Steel; Ch. 4 of Imhoff-
                                            Fair; and ASCE Sewage Treatment
                                            Plant Design, Ch. 5.


Cutters , Shredders  (comminutors)

     Cutters  and shredders  are usually located after grit removal to prevent
excessive wear on cutting edges and before the sedimentation unit so the
shredded particles  can be added back to the wastewater treatment stream and
removed by sedimentation.   Generally, fine racks and fine screens have been
replaced by the cutting screens of communutors.  These units are found in a
variety of sizes, capacities, and configurations.  Those include up and down
moving cutting edges on bar racks and units that function like a kitchen sink
garbage disposal with rotating cutter edges.
                                            For additional information see:

                                            Ch. 22 of Steel; Ch. 3 of Imhoff-
                                            Fair.
Fine Screens

     Fine screens are used in old plants where cutters and comminutors were
not installed and in newer plants as partial treatment of certain industrial
wastes (e.g., cannery, brewery, distillery or packing house).  They are
usually located after the grit and pre-aeration units and before the
sedimentation unit.

                                     C-5

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      7046
     Fine screens may be made up of a series of disk screens with a frustum
of a cone superimposed upon it.  It rotates slowly, with brushes sweeping
the screenings from the part above the wastewater flow to a conveyor belt
or hopper.  Drum screens are of several types.  Basically, screenings are
accumulated on the outside of a drum as it rotates or on the inside of a
drum as the flow passes through.  Conveyors and collectors then handle the
retained solids.
                                            For additional information, see:
                                            Ch. 22, Steel; Ch.  3, Imhoff-Fair;
                                            Ch. 4, ASCE Sewage  Treatment Plant
                                            Design.
Aeration and Chlorination

     Aeration and Chlorination are utilized to minimize odor and grease
problems.  Chlorine added to wastewater causes grease to coagulate.   This
process also reduces the finely divided suspended solids load on the primary
sedimentation and biological treatment units.   The cohesive force of the
wastewater is reduced by the diffused air bubbles that buoy up the grease
and suspended solids which are then skimmed off.   This unit may follow the
grit chamber and cutters.  It usually precedes the fine screens and/or
primary sedimentation unit.
                                            For additional information, see:

                                            Ch. 20, Fair & Geyer;  Ch.  6, ASCE
                                            Sewage Treatment Plant Design;
                                            Ch. 3, Imhoff-Fair.
Sedimentation

     Sedimentation (in primary treatment)  usually follows grit removal,
screening and pre-aeration.  It precedes final Chlorination and/or discharge
to the receiving waters or other effluent  disposal areas.  It reduces the
suspended solids and organic loading on subsequent secondary and advanced
waste treatment units.

     Sedimentation tanks may be constructed with or without mechanical
devices for continuous removal of sludge.   Tanks are classified by
        • Primary - in which raw wastewater is settled

        • Secondary of Final - in which mixed liquors or activated
          sludge plants or trickling filter effluents are clarified
                                     C-6

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      7046
        •  Intermediate - when used between filters in a two-stage
          trickling filter plant

        •  Septic tanks - combine sedimentation and sludge digestion
          in the same compartment

        •  Imhoff tanks (two-story tanks) - combine sedimentation and
          sludge digestion but are designed so that the processes are
          carried on in separate compartments arranged one above the other

     Municipal wastewater contains both granular and flocculent solids.
Based on this condition, the required capacity of primary settling tanks is
both a function of surface loading and of volume loading or detention period.

     A number of factors affect the performance of sedimentation tanks and
the designs are influenced by those parameters which have the greatest
impact on the desired results.  Some of the commonly considered parameters
are:
        •  Variation from 16-hour average flow

        •  Temperature variation (of the wastewater, as it affects the
          density and viscosity of the liquid)

        •  Density currents

        •  Solids concentration
        •  Solids removal

     The mechanism of sedimentation is based on the settling velocity of
particles.  A particle in a still fluid of less density will move vertically
downward because of gravity.  The time required for the optimum percentage
of these particles to drop out is the theoretical detention time of the
settling basin.  This time varies with what the next treatment mode is.
Fig. C-4 shows the removal of suspended solids and BOD from wastewater in
primary settling tanks (after Imhoff and Fair) as it varies with detention
time.  A secondary mechanism affecting the performance of the sedimentation
tank is its overflow rate.  A case in point is a high overflow rate with
overflow velocities which exhibit a high scouring and solids-carrying
capacity in wastewater effluent.  The allowable values of overflow rates
are dependent on the next mode of treatment.
                                     C-7

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       7046
                                      3   4
                                     Time, hours
               Fig. C-4.   Percent of Suspend Solids and BOD5
     Both of these mechanisms are influenced by changes in the temperature
of the wastewater.  By increasing the temperature, it reduces the viscosity
and density of the fluid, thereby increasing the settling velocity of the
particles and reducing the detention time required.   Along with this,
characteristics of effluent quality over the overflow weir would be changed.

     Figure C-5 shows the various types  of sedimentation tanks and their
sludge collection systems.
                                            For additional information, see:

                                            URS Project 7032; Ch. 9 & 23,
                                            Steel; Ch. 4, Imhoff-Fair; Ch. 3,
                                            ASCE Sewage Treatment Plant
                                            Design.
                                    C-8

-------
                 REPRESENTATIVE
                 LONGITUDINAL-FLOW SETTLING TANKS
                    it   ;r
                           ^
                           (a)

       Rectangular, hand-cleaned
       tank with sludge hopper
'_jj"~   Tank a provided with track-
       mounted sludge scraper
       (Mieder tank)
                                         Rectangular, hopper-
                                         bottomed tank with
                                         hydrostatic sludge
                                         removal
O
(O
                              i-
     Square tank with cross flow
     and rotary sludge scraper
     (Dorr Co.)


~^   Rectangular tank with sludge
^    scraper and scum collector
     (Link-Belt Co.)
                                  ^i7.>i   Tank e with cross collector
                                 IjlPJi    for sludge and scum
                                         (Link-Belt Co.)
                                                              MODIFIED IMHOFF TANKS
                                                              WITH SMALL SLUDGE SUMPS

                                                              Horizontal flow
                                                                                                  Vertical and radial flow
                                                                REPRESENTATIVE VERTICAL &
                                                                RADIAL-FLOW SETTLE  TANKS

                                                                 Hopper-bottomed,  circular
                                                                or square tank with hydrostatic
                                                                sludge removal (Dortmund tank)
                                                                                              .—  Tank ! equipped with
                                                                                                  sludge scraper
                                                            PI*;..  Circular tank with sludge
                                                                 collector to which scum
                                                                 collector can be added
                                                                 (Dorr Co.)
H
 o
 Ol
                                                       Fig. C-5.   Settling Tanks

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      7046
CHEMICAL PRECIPITATION


     Chemical precipitation processes obtain effluent quality which is in
the range between primary sedimentation and the biological oxidation
processes.  The most effective use of chemical precipitation is under the
conditions of seasonal variations in volume, strength or degree of treatment
required of the wastewater.  In plants that are not specifically designed
for chemical precipitation, it is not uncommon for chemicals to be added
prior to primary or secondary sedimentation to aid in the settling process.

     The process of chemical precipitation functions under one of three
mechanisms or under all three at the same time:
        •  Mechanical entrapment - heavy metal salts (such as alum or
          ferric chloride), plus an alkaline material, produce large
          volumes of precipitates which settle out true and colloidal
          suspension in wastewater

        •  Particle charge - colloidal particles with electrical charges ,
          plus chemicals with opposite charges (polyelectrolytes),
          neutralize each other and settle out
        •  Physical - insoluble chemicals (such as activated carbon)
          with large surface areas either absorb or act as nuclei for
          the colloids and start settling

     As in primary sedimentation, detention time under quiescent conditions
is an important part of the processes, with detention times similar to
primary sedimentation.
                                            For additional information, see:

                                            Ch. 9, ASCE Sewage Treatment
                                            Plant Design; Ch. 9 & 23,  Steel.
CHLORINATION

     Final chlorination is used to disinfect (destroy the pathogenic
organisms harmful to man or animals)  treated effluents before they are
discharged to the final receiving waters.   To accomplish disinfection,
enough chlorine is added to satisfy the chlorine demand of the waste while
leaving a chlorine residual to destroy the pathogenic organisms.   The amount
of chlorine required for disinfection is largely dependent upon the organic
matter present.  The performance of the chlorination process is affected by
the quantity of chlorine used, waste characteristics, where the chlorine is
applied and how well it is mixed.   The contact chamber should have a cleaning
and flushing system to prevent buildup of sludge due to solids carry-over
from the final settling tank and grease.  Figure C-6 shows a typical baffled
                                    C-10

-------
Chlorine Contact Tank
      Baffle
   Baffle
               A
               \.
Flow Control Weir
                                         \
                                                 Final  Effluent
                                                 to Receiving Water
                                                 Weir

                                                 Scum Baffle
                                                  Mixing Baffle
                                            Chlorine Diffuser
                                                                Influent
                                                                from Final
                                                                Treatment
                                                                Processes
                                                      Chlorine Source
                             PLAN VIEW

Baffle ^
\

1
- 1

i
X

^
/
^^- Mixing Baffl
)
A
\A/~:- ^^~Ll 	 :__ r\:cc... -
                           SECTION A-A
               Fig.  C-6.  Final  Chlorination System
                                C-ll

-------
      7046
chamber.  To be most effective, the contact time should be not less than
15 minutes at maximum flow.

     There are some State health departments which require a residual of
2.0 mg/1 after 15 minutes.  All such requirements should be checked before
plants are inspected.

     There is a secondary benefit of proper effluent chlorination.   At the
point where orthatoline residual is produced, each mg/1 of chlorine absorbed
will satisfy and remove approximately 2 mg/1 of BOD  in the treated effluent.
                                                   o
                                    C-12

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-------
SECONDARY
TREATMENT  MODE
(Background  Info)

-------
      7046
                                 Appendix D

                            SECONDARY TREATMENT
     This section of the manual contains background information on pro-
cesses now being used in the secondary treatment process of wastewater.
It delineates the basic biological mechanism which takes place in the
various biological reactors,  a description of these reactions and how they
fit into the treatment scheme, and a list of references for each process
for additional information.

     The tables located in Section II of this manual list the common
secondary treatment operating parameters, loading rates , and support sys-
tems which are used in conjunction with each process.   This information,
along with this section and the common problems and solutions for secondary
treatment (Section IV of this manual) , should be reviewed for a general
background to expedite the plant evaluation and help in finding solutions
to process problems in this area.

     As in pre- and primary treatment , there are many configurations that
can be representative of secondary treatment.  The unit operations which
are shown in Figure D-l make up the basic secondary mode of treatment.

     In secondary treatment , flow is received from the primary treatment
system.  This flow then enters a biological reactor where biological
growth occurs.  This growth "fixes" most of the remaining organic materials
in a biological mass (biomass).  This biomass is then removed by sedimenta-
tion in the secondary clarifier.  Some of the sludge (settled biomass)  is
returned to the inlet of the biological reactor and is mixed with the
incoming primary effluent so that organisms with increased assimilation
capacities can work on the waste.  The effluent from the secondary clarifier
is then chlorinated and discharged to the receiving body.

     The biological reactors which are in common use in wastewater treat-
ment were listed in Appendix A of this manual.  They can be operated in
many modes, depending on plant area limitations or treatment desirability.
In many cases the only prior requirement to the use of a biological reactor
is primary treatment.
                                    D-l

-------
to
                               Wastewater
                                    1
                              Pre- Treatment
                                                                                            Secondary Clarifier












MB


1 1 . 1 1 1 , . ll
'•> — c ' 1 I » *
Primary Sedimentation _ f i Biological Reactor
— N X> 1 1
3 T j ^ ' '
• i i i i ir r i^ i 1
/ 1 1
1 |

i fTV,
^--s\
1 Sludge
Treatment
Fffliionf _—___«_
Sludge
Wastewater
Effluent
To Final
Receiving Body
1
.xCt 1

I r" i i
N^
i
1
..-J P LA. _ ^lnHnn

^ 1

"~ "^ ~~ ~ " *• Final S
Dispose

Chlorine
Chamber XTN.











udge
1



                I	^
o
£>
cn
                                                                                                      Chlorination
                                Fig. D-l.   Flow  Diagram  of a Secondary  Treatment System

-------
     7046
GENERAL BACKGROUND ON A BIOLOGICAL REACTOR
     In nature, bacteria and other microorganisms break down organic
materials (the substrate) found in wastewater into simple, more stable
substances.   A biological (aerobic) reactor provides a place where organic
waste is brought into contact with the surface, contact, or interfacial
forces of biological slimes, or films, zoogleal aggregates, activated
sludges or activated surfaces to remove suspended and finely divided solids
and dissolved organic matter by the mechanisms of adsorption and coagulation,
and enzyme complexing.  Whatever the individual operation of the biological
reactor, the  microorganisms which stabilize the wastewater must have a
continuous supply of substrate (food) , an adequate supply of oxygen
(aerobic systems only) and a suitable supporting film of floe.

     The reactions involved in the reduction of organic material in the
wastewater during biological oxidation can be interpreted as a three-phase
process:

     1.  an initial removal of BOD on the contact of a waste with a
         biologically active sludge or film  which is stored in the
         cells of the organism as a reserve food source

     2.  removal of BOD in direct proportion to biological sludge
         or film growth

     3.  oxidation of biological cellular material through endogenous
         respiration.
                                            For additional information, see:

                                            Ch. 2, Eckenfelder & O'Connor;
                                            Ch. 1, Rich Unit Process;
                                            Ch. 6, Imhoff-Fair.
                                    D-3

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     7046
TRICKLING FILTERS

     A trickling filter is a fixed bed system over which wastewater is
intermittently or continuously discharged and contacted with biological
films on the filter media.  Through this contact nonsettleable suspended
matter and colloidal and dissolved organic matter are removed from settled
wastewater by the organisms to be used as food.

     A schematic representation of mechanism involved in the trickling
filter processes is shown in Figure D-2.  The largest portion of the waste-
water applied to the surface of the filter passes rapidly through the filter,
and the remainder slowly trickles over the surface of the slime growth.
The reduction of organic loading occurs in two stages:
         •  the wastewater passes rapidly through the filter and
            removal occurs by biosorption and coagulation
         •  soluble constituents are removed from the remaining
            portion of flow due to the substrate utilization by
            the organisms.
                        AIR
FILTER^/
MEDIA //
\
H2S
ORGANIC
ACIDS
ANAEROBIC
EFFECTIVE
FILM DEPTH
-* 	 h 	 »•
BOD
°2
co2
AEROBIC
WASTE
1 1

i
AIR
                       Fig. D-2.  Trickling Filter
                                    D-4

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     7046
Classification of Trickling Filters

     Filter classification is based on applied hydraulic and organic (BOD)
loadings (Section II of this manual shows typical loading rates).

         •  Low-Rate (Standard or Conventional Filter) - Low-rate filters
            usually operate with intermittent dosing.   The wastewater is
            applied to the filter surface and passes through the filter
            with its effluent going to the secondary clarifier without
            recirculation.  The filter depth is usually greater than for
            high-rate filters.

         •  High-Rate - Wastewater is applied much in the same manner as
            in the low-rate filter.  However, the hydraulic loading is
            five to fifteen times, as great, with the organic loading
            being four to five times greater.  Along with the higher
            loading rates , the high-rate filter is characterized by the
            recirculation of a portion of the wastewater.

         •  Roughing Filter - Roughing filters are used to reduce the
            organic load applied to subsequent filters of activated
            sludge units.  They are designed on the basis of the
            volume of liquid applied to filter.  They will also handle
            a greater organic loading than low- or high-rate filters,
            but with reduced removal efficiencies.

     Trickling filters, like most biological reactors , are followed by a
final sedimentation process to remove any biomass which is lost from the
reactor.  This final sedimentation process is figured in total process
efficiency when it is calculated.
                                            For additional information, see:
                                            Ch. 6, Eckenfelder-O'Connor;
                                            Ch. 24, Steel;
                                            Ch. 6, Washington State Waste-
                                              water Plant Operation Manual;
                                            WPCF Publication No. 14,
                                              Sec. 15, Ch. 11, ASCE Treat-
                                              ment Plant Design.
                                    D-5

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     7046
ACTIVATED SLUDGE

     The activated sludge process is based on the utilization of a floe
made up of microorganisms, non-living organic matter and inorganic materials.
These are brought into contact with primary treated wastewater (in most
cases) in the presence of dissolved oxygen.  A high degree of mixing causes
the removal of settleable solids, nonsettleable suspended solids, colloidal
solids and dissolved organic matter.

     The basic process flow includes:

         •  Aeration of pre-primary treated wastewater for a
            period of time

         •  Final clarification for the separation of solids and
            liquids at the end of the contact time

         •  The return of a percentage of the separated solids to
            the reactor for mixing with influent wastewater

         •  Discharge of the liquid wastewater fraction as
            process effluent.
Classification of Activated Sludge Processes

         •  Conventional (plug flow).   All primary-treated wastewater is
            introduced at one end of  the reactor along with the returned
            sludge.  The length of the reactor is usually 5 times the
            width.  The diffusers are located along one side of the
            tank so that the diffused air bubbles cause a circular
            rolling motion on an axis parallel to the length of the tank.
            This class of activated sludge process provides insufficient
            dissolved oxygen content  at the influent part of the reactor.

         •  Modified (high-rate).  This process utilizes short aeration
            periods and low activated sludge concentrations.  It is
            characterized by low BOD  removals (40-70) and a low percentage
            of sludge return (10%).  Also associated with this process is
            a high solids accumulation due to insufficient time for
            significant oxidation of  cellular mass and the retention of
            influent inerts.

         •  Step Aeration.   Primary treated wastewater enters this
            reaction at a number of different points along one side of
            the reactor, but with the returned sludge being introduced
            at the point of first entry, with or without a portion of the
            incoming wastewater.   The greatest concentration of sludge
            solids in the mixed liquid is where the final amount of waste
            is introduced and decreases as more waste is introduced at
            subsequent points.   By entering the waste in this manner, a
            more uniform aeration of  the waste occurs, and a decrease in
            detention time is possible.

                                    D-6

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7046
       Tapered Separation.   Basically the same concept as step
       aeration except that the air is added in stages along the
       reactor instead of the wastewater.  The air requirements
       are staged to give maximum amount at the inlet of the raw
       waste with the rest regulated to meet oxygen utilization
       in other sections of the reactor.  This process is supposed
       to provide better control in meeting shock loadings.

       Kraus Process.  This is a modification of conventional
       activated sludge where incoming wastewater (primary treated
       water) has insufficient amount of nutrients (usually nitrogen)
       available to provide a stable activated sludge process.  These
       nutrients are provided by the recycling of digester mixed
       liquor to the activated sludge system by means of a nitrifica-
       tion tank where a mixture of supernatant and returned activated
       sludge is aerated 24 hours and returned to the activated sludge
       unit.  Aside from supplying the needed nutrients , there are
       other beneficial effects from this process:  it provides an
       oxygen reserve in the form of nitrates and also tends to weight
       the sludge thus providing better settling characteristics.

       Completely Mixed Reactor.  The primary treated waste is
       completely mixed throughout the reactor as quickly as possible.
       The process provides for immediate distribution for all incom-
       ing waste, and the oxygen requirement throughout the tank is
       uniform.  This process minimizes the effect of slug loadings
       of very strong waste or short term, high volume wastes (shock
       loadings).

       Contact Stabilization.  Incoming primary-treated wastes (some
       new plants omit primary sedimentation) are mixed with returned
       sludge in a contact basin for a period of 30 minutes to one
       hour in which most of the absorption of solids is accomplished.
       This short contact permits solubilization of the absorbed
       organic solids before the absorption by microorganisms in the
       activated sludge of the soluble organics.  This process is
       also affected by a highly variable influent flow rate which
       reduces the adsorption time causing high effluent BOD.

       Two Stage Aeration.   This is basically the same as contact
       stabilization except that the contact time is six times as
       long, providing enough time for absorption, solubilization,
       absorption and the synthesis of cellular material.  The
       aeration time of the second reactor is long enough to provide
       for the oxidation of a large portion of the synthesized cell
       mass.
                               D-7

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     7046
            Extended Aeration.   This type of system is usually provided
            for a small-sized treatment  facility.   This system is
            completely mixed with a low  food/microorganisms (F/M)
            loading rate for a given population,  which allows  for almost
            complete oxidation of synthesized cell mass.   It is also
            characterized by low oxygen  uptake rate.
                                            For additional information, see:
                                            Ch. 2,  3 & 6,  Eckenfelder-
                                              O'Connor;
                                            Ch. 6,  State of Washington
                                              Wastewater Plant Operators
                                              Manual;
                                            Ch. 25, Steel;
                                            Ch. 10, ASCE Sewage Treatment
                                              Plant Design.
STABILIZATION PONDS AND LAGOONS

     The operation of stabilization ponds  and lagoons that are aerobic
depends on oxidation and reduction by microorganisms, sedimentation,  bio-
flocculation and anaerobic digestion of bottom sludge.   The oxygen utilized
in this process is obtained from the algae growth present or mechanical and
diffused aerators with additional oxygenation being provided by wind  and
wave action.  Some ponds operate anaerobically in much the same way as a
digester with sufficient depth to create anaerobic conditions due to  poor
oxygen transfer to the deep parts of the pond.

     The effluent from this treatment process is  disposed of by percolation
(where ground water regulations permit), evaporation, transpiration from
irrigation of cover crops or discharged to a receiving body.

Classification of Stabilization Ponds and  Lagoons

     The classification of stabilization ponds and lagoons may be according
to: depth, main source of oxygen, rate of  waste loadings (Ib of BOD per
acre per day), inlet, flow-through, and inlet and outlet arrangements
including load distribution, recirculation,  and effluent disposal.   In
general, stabilization ponds and lagoons may be classified into three types:

          »  Large Holding Reservoirs.  These are characterized by long
             detention times (months, usually) with the oxygen being
             supplied by surface aeration and dilution of the wastewater
             with clean water.  The removal  of organics is accomplished by
             bio-flocculation, oxidation,  and reduction with an aerobic
             digestion of bottom  sludge taking place.
                                   D-8

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     7046
          o  Stabilization Ponds.  The rate of oxidation of organic
             matter by microorganisms exceeds the rate of natural surface
             aeration and the algal growths must supply the additional
             oxygen required.  Since solar energy is required for photo-
             synthesis, the depth of the ponds is limited.  Location is
             also a limiting factor as climatic parameters are very
             important.  The detention times in stabilization ponds
             range from less than a week up to six weeks , depending on
             the type.

               a.  Facultative Ponds.  This type of pond is characterized
                   by the aerobic and anaerobic processes occurring
                   simultaneously.  The removal of organic material is
                   accomplished by sedimentation, bio-flocculation and
                   aerobic oxidation.  The primary source of oxygen is
                   obtained from algae growth with a second source
                   supplied by wind and wave action.

               b.  High Rate Ponds.  This pond is characterized by its
                   shallow depths for extreme solar energy penetration;
                   it is fully mixed and completely aerobic.  The organics
                   in this system are oxidized by microorganisms utilizing
                   oxygen generated by algal growths.

          o  Aerated Lagoon.  This system is characterized by the use of
             mechanical aeration to supply the required oxygen supply
             directly, causing sufficient mixing to supply additional
             oxygen from surface aeration, so that the lagoon remains
             aerobic.
                                            For additional information, see:

                                            Ch. 6, Eckenfelder-0'Connor;
                                            Ch. 12, ASCE STP Design
                                            Ch. 21, Steel.
INTERMITTENT SAND FILTERS

     Intermittent sand filters are being phased out of secondary waste
treatment mode due to the large area requirements.  Because of the high
quality effluent produced, they may be used in advanced waste treatment
modes on a smaller scale to polish secondary treatment effluent.

     The basic mechanism of this process is a straining effect produced
by sand grains which trap suspended solids.  The intermittent dosing
(twice during a 24-hr period) permits air to enter the bed to allow micro-
organisms to reduce the organic load aerobically.  It should be noted that
work done by Grantham, Emerson and Henry in Florida indicates that sand
                                   D-9

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      7046
size affects the percentage of organic material removed.
                                             For additional information,  see:
                                             Ch. 12, ASCE STP;
                                             Ch. 24, Steel.
SECONDARY CLARIFICATION

     This unit follows the biological reactor (such as the trickling filter
of activated sludge).  Its primary functions  are to retain the biological
growths produced by the reactor for recycling and to produce clarified
liquid in the overflow and thickening on the  bottom of the tank.   This
depends on the physical and chemical nature of the sludge and the hydraulic
characteristics of the clarifier.

     The clarifiers can be rectangular or circular in shape.  In both types
of clarifiers, their size is related to one of the following factors:

          •  Surface of clarifier area over the M.L.S.S.  concentration
          •  Surface area and volume of clarifier for producing thickening
             and underflow of a desired concentration
          •  Volume for retention of settled  sludge

Along with these requirements, the velocity of the density currents  are
critical in the clarifier.  If these velocities are increased, the critical
value for separation of solids could be exceeded causing bottom scour with
the possibility of carryover of low density particles in the effluent.
                                             For additional information,  see:

                                             Ch. 4,  Rich,  Unit Operations of
                                               Sanitary Engineering;
                                             Ch. 5,  Eckenfelder-O'Connor;
                                             Paper by Clair Sawyer -  Final
                                               Clarifiers, and Clarifier
                                               Mechanisms  (MIT);
                                             Ch. 8,  ASCESTD.
                                     D-10

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lillcd  7046


PACKAGE AERATION PLANTS

     This type  of  treatment  system  is  characterized by

          •   low daily flow
          •   no primary  sedimentation
          •   20-24 hour  aeration period

          •   long  final  sedimentation  period
          •   limited  flow control between processes due  to close
              proximity of operations.

The  basic mechanism of the process  is  to keep  the microorganisms predomi-
nantly in the endogenous growth phase  (organisms are using all material  in
absence of organic material  growth)  through long detention time and  a low
food-to-microorganism ratio  in the  aeration tank.

     Two systems in common use consist of:

          •   aeration tank and final sedimentation tank  plus  chlorination

          •   mixing chambers,  sedimentation tank, and sludge  reaeration
              tank  plus chlorination.

Both of the  systems utilize  aerated digestion  of the activated sludge.
Critical to  successful operation of these plants is a program of effective
solids removal  from the  system.


                                             For additional information, see:
                                             "Aeration Plant  in Florida",
                                               ASCE Jour, of  Sanitary Eng.,
                                               Vol. 88;
                                             "Field Evaluation of  the
                                               Performance of Extended
                                               Aeration  Plant", J. WPCF,
                                               Vol. 41,  July  1969, p. 1299.
                                      D-ll

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ADVANCED
TREATMENT  MODE
(Background  Info)

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     7046
                                 Appendix E
                       ADVANCED WASTEWATER TREATMENT
     Advanced wastewater treatment processes are described in this section
of the manual.  It delineates how the process works, the various organic
and inorganic constituents which are removed by the processes, removal
percentages which can be expected, and references for additional information.

     The tables in Section II of this manual list the common advanced
waste treatment operating parameters, a range of materials accumulated due to
process operation, and support systems which are used in conjunction with
each process.  This operating information, together with the common problems
and suggested solutions, should be reviewed with the information in this
section to provide background data against which an advanced waste treatment
plant can be evaluated.
GENERAL BACKGROUND

     In the past few years the United States has experienced rapid popula-
tion growth, concentration of people in urban areas, and the appearance of
ever larger industrial -establishments.  All of these factors have contributed
to increased pollutional loads on streams, rivers,  and other receiving
waters.  The result has been that conventional primary and secondary treat-
ment processes are not always able to provide adequate removal of pollutants.
For this reason, advanced waste treatment processes have been developed to
remove pollutants not handled by conventional (primary and secondary)
treatment.  Advanced waste treatment is intended, therefore, to alleviate
pollution of a receiving watercourse.  It may also, however, be used to
provide a water quality adequate for reuse, since the population expansion
and increased water demand mean that more and more  people have water supplies
that must be used more than once for industrial and domestic purposes.

     It should be pointed out that certain materials to be removed by
advanced waste treatment are normally removed to a  great extent by secondary
treatment (e.g. , 90 to 95 percent of suspended solids are removed in an
efficient secondary plant).  Advanced waste treatment, which is important
whenever upsets occur in such a secondary plant, is physical-chemical
treatment.  This process, due to its reliability, could also be used in
cases where direct water reuse is anticipated and 90 to 95 percent removal
is inadequate.  Advanced waste treatment is more commonly used, however,
for materials which are not efficiently removed by  primary or secondary
treatment (e.g., phosphates and nitrates).
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     In general, advanced waste treatment is applied to effluent from
conventional secondary processes for the purpose of removing one or more of
the following constituents: soluble organic compounds, soluble inorganic
compounds (nitrogen and phosphorus), particulate solid material, and
pathogenic organisms.

     The following paragraphs examine selected advanced waste treatment
unit operations to provide descriptions of the processes involved and
present references of interest for additional detailed information.
CHEMICAL/PHYSICAL TREATMENT

     Chemical precipitation and sedimentation is a treatment method
combining chemical and physical elements to achieve removal of soluble
inorganic compounds (such as phosphorus) or removal of suspended solids in
a colloidal state.  A mineral or synthetic polymer is added to the wastewater
and chemically reacts with one or more constituents of the wastewater to
produce a precipitant.  This precipitant is then coagulated or flocculated
by means of the mechanical action of mixing or the addition of a coagulation/
flocculation aid.  The precipitant is subsequently removed by sedimentation.
In this process, constituents of the wastewater are removed in several ways:

          •  chemical reaction with the material added and sedimentation
            of the resulting precipitant
          •  physical capture of suspended solids by the descending
            precipitant
          •  adsorption of particles and dissolved constituents by
            the precipitant.

Removal of phosphorus is typically obtained by addition of calcium, aluminum,
or iron salts (e.g. , lime, alum or ferric chloride).   Phosphorus removals
vary from about 70 to 95 percent.

     Chemical/physical treatment can be applied to secondary effluent or
to primary effluent.  In an activated sludge plant, efficient removals have
been achieved by mineral addition before primary settling, after primary
settling, in the aeration tank, or near the mixed liquor exit point.   In a
trickling filter plant, the precipitation is usually accomplished in the
primary sedimentation tank.  Final chlorination and discharge to receiving
water follows chemical/physical treatment after it is used in secondary or
advanced waste treatment.

     Chemical/physical treatment is basically a sedimentation process and
has associated with it the same type of equipment and performance parameters
as in primary or secondary sedimentation.  Additional equipment is, however,
required to store and feed the required additional materials into the
sedimentation tank.  Specialized equipment and instrumentation are necessary
                                     E-2

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      7046
since slurries often are involved and pH control is critical.
                                            For additional information, see:
                                            Ch. 2, Gulp and Gulp
                                            Ch. 26, 29 and 30, Fair, Geyer
                                              and Okun
                                            Advanced Waste Treatment Research
                                              Series AWTR-2, -12
                                            Advanced Waste Treatment Seminar,
                                              Session II (Oct. 1970)
CARBON ADSORPTION

     Carbon adsorption is a treatment method used to remove residual
dissolved and suspended organic material from wastewater treatment plant
effluents.  These organic pollutants are typically responsible for the color,
odor, taste, and froth problems of wastewater.  In carbon adsorption, the
wastewater is continuously run through a bed or column of activated carbon
which removes the organic materials by adsorption.  When the adsorption
capacity of the columns is exhausted, the wastewater is rerouted through
another bed of carbon and the exhausted carbon is regenerated for use again.

     In actual plant experience (South Tahoe) , the carbon adsorption process
has yielded the influent entering it the following removals: BOD - 70+%;
COD - 50+%; TOC - 75%; color - 75%.  In pilot plant tests, removals of
suspended solids have run up to 90% and removal efficiencies even greater
than those shown above have been experienced.

     Conventional primary and secondary treatment removes organic matter
to a great extent.  The difficult-to-remove organics (refractory organics)
are handled by carbon adsorption.   Carbon adsorption, therefore, follows
secondary treatment and precedes chlorination.

     The activated carbon must be of the proper type to adsorb materials
present in the existing wastewater.  Many different types are available,
and the actual type and quantity to use depend on the kind and concentra-
tions of pollutants to be removed.  In addition to variations in the
adsorption characteristics, activated carbon also varies in physical form
from powdered to granular.  Since the carbon is stressed during regenera-
tion and transported between generations, it must be durable to such
stresses and still maintain performance.  The granular carbon is generally
optimum from an overall cost performance, endurance, and recovery point
of view.

     The carbon columns may run from 8 to 12 ft in diameter and 24 to 60 ft
tall.  Usual operation is to run the wastewater through from two to four
columns in series.  The most important factors in column operation are
                                     E-3

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      7046
contact time, pretreatment,  and flow conditions within the column itself.

     For regeneration, the spent carbon is transported from the column in
water slurry and fed by screw conveyor into a regeneration furnace where
intense heat burns off accumulated material, opening the interstices of
carbon for additional adsorption.   Makeup carbon is added as needed and
the regenerated carbon is returned to the column (again in the slurry).
                                            For additional information,  see:
                                            Ch. 7 and 8, Gulp and Gulp
                                            Ch. 26, Fair, Geyer and Okun
                                            Advanced Waste Treatment Research
                                              Series 9, 10, 11 and 16
                                            Advanced Waste Treatment Seminar,
                                              Section III.
AMMONIA STRIPPING

     Ammonia stripping is a treatment method for specific removal of nitrogen
in the form of ammonia.  The process  is  one in which the wastewater is cas-
caded down a stripping tower and air  is  forced up through the tower.   The
air strips the dissolved ammonia from the water and carries it off into the
atmosphere.  Removal efficiencies up  to  90% have been achieved.

     Neither conventional primary nor secondary treatment removes significant
amounts of nitrogen, but the biological  process does convert nitrogen com-
pounds in the wastewater into ammonia.  Ammonia stripping, therefore, follows
secondary treatment and precedes chlorination.

     Effective ammonia stripping requires a high pH and high air-to-liquid
loadings.  Both of these factors are  temperature dependent, such that when
air temperatures are lower, the corresponding pH and air loadings must be
higher to give the same ammonia removal.   Normal operation calls for a pH
of above 11 and air rates of from 200 to 500 cfm/gpm.

     Actual ammonia stripping towers  are very similar to forced-draft type
cooling towers.  The pH adjustment takes place before entry of the waste-
water to the stripping tower.  In a typical operation, the pH adjustment,
using lime and a phosphorus removal step, takes place in a clarifier just
before feeding the wastewater to the  stripping tower.  After passage through
the tower, recarbonation is performed to readjust pH as needed to prepare
the wastewater for filtration, carbon adsorption, chlorination,  or final
discharge.  In the recarbonation process, an intermediate reaction or
settling basin exists between the two recarbonation basins.  In the settling
basin, a dense floe rich in calcium carbonate is formed, and this is a
source of material to reclaim lime for reuse.
                                    E-4

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      7046
     In an advanced waste treatment scheme, therefore, the secondary
effluent proceeds through a chemical/physical treatment for phosphorus
removal, then ammonia stripping, carbon adsorption, and finally filtration
and/or desalting.

     Two problems that may occur with ammonia stripping are:  1) the
inability to operate at air temperatures below 32 F; and  2) the deposition
of calcium carbonate scale on stripping tower surfaces.
                                            For additional information, see:
                                            Ch. 4 and 5, Gulp and Gulp
                                            Ch. 28 and 31, Fair, Geyer and
                                              Okun
                                            Advanced Waste Treatment Seminar,
                                              Session 1.
ELECTRODIALYSIS

     Electrodialysis is a membrane desalting process for removal of dis-
solved inorganic ions from wastewater.  In the process, membranes are used
which are permeable to charged ions and impermeable to ions of the opposite
charge.  A pair of opposite membranes has a direct current potential applied
across them and the wastewater is pumped between them.  Positive and negative
ions, therefore, permeate out of the wastewater, and a product with lower
dissolved minerals results.  In addition, a brine stream very concentrated
in dissolved minerals also results.  Electrodialysis is capable of yielding
product water with up to 85% of the total dissolved solids removed.  In this
process, nitrogen removal is about the same as total dissolved solids, but
phosphorus and CO do not show the same high removal.  A typical system will
yield about three gallons of product water and one gallon of brine for every
four gallons of feedwater treated.

     Conventional primary and secondary treatment does not remove significant
amounts of dissolved inorganics.  Electrodialysis usually follows carbon
adsorption which removes constituents capable of fouling the electrodialysis
membranes (non-ionic particles).

     Normal operation of electrodialysis requires pH control , chemical
control of scale formation, and routine flushing and cleaning of membrane
surfaces.  Proper disposal of the brine stream is important and this may
consist of ocean dumping (where it is still permitted), evaporation pond
utilization, or deep well injection.
                                    E-5

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flffi 7046
                                            For additional information, see:

                                            Ch. 21 and 30, Fair, Geyer and
                                              Okun
                                            Advanced Waste Treatment Seminar,
                                              Section IV.
REVERSE OSMOSIS

     Reverse osmosis is a membrane desalting process for removal of
dissolved inorganic materials from wastewater.  In the process , membranes
are used which are permeable to pure water, but nearly impermeable to
dissolved salts when operated at high pressure.  Product water with lower
dissolved minerals is forced through the membrane, and a brine stream very
concentrated in dissolved minerals is rejected by the membrane.  Reverse
osmosis is capable of yielding product water with up to 85% of the total
dissolved solids removed.  In this process, phosphorus, COD, and ammonia-
type nitrogen are removed about as efficiently as the total dissolved
solids, but nitrate-type nitrogen is less efficiently removed.  A typical
system will yield about three gallons of product water and one gallon of
brine for every four gallons of feedwater treated.

     Conventional primary and secondary treatment does not remove signifi-
cant amounts of dissolved inorganics.  Reverse osmosis usually follows
carbon adsorption in an advanced waste treatment scheme so that fouling of
membranes is avoided.

     Normal operation of reverse osmosis requires pH control, chemical
control of scale formation, and routine flushing and clearing of membrane
surfaces.  Proper disposal of the brine stream is important, and this may
consist of ocean dumping, if still permitted, evaporation pond utilization,
or deep well injection.
                                            For additional information, see:
                                            Ch. 21 and 30, Fair, Geyer and
                                              Okun
                                            Ch. 10, Culp and Gulp
                                            Advanced Waste Treatment Seminar,
                                              Section IV.
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SOLIDS  TREATMENT
AND DISPOSAL

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                                Appendix F

                       SOLIDS TREATMENT AND DISPOSAL
     This section of the manual supplies background information on the
various processes involved in handling and treating of solids accumulated
during the wastewater treatment process.

    Sludges are characterized by their percentage water content, volatile
matter, and the various processes by which they are produced.  In addition,
this section explains the methods available for final solids  disposal.
A comparison of operational parameters and loading rates (design specifica-
tion) with those presented in this manual or in other sources will facili-
tate an evaluation of the solids  treatment and disposal system.  Deviations
from normal will reveal any problem areas.  A check of the common operating
parameters, loading rates, and support systems which are generally used in
solids handling (Tables II-5 and II-6 in Section II) should also be made.
These  tables, along with the common problems in solids handling (Section IV),
and a  review of this section will supply information needed for a general
evaluation of the solids  handling program carried on at the wastewater
treatment plant.
GENERAL BACKGROUND

     The solids accumulated from the various wastewater treatment processes
can be grouped into one of two categories: those trapped on medium and fine
screens in pretreatment, and those formed from processes in the primary,
secondary and advanced treatment modes.

     Large-size material trapped by racks, such as glass bottles, rags, or
pieces of wood, is collected and usually buried in a sanitary landfill.
The solids from medium screening are shredded and treated by anaerobic
digestion,  along with fine-screen solids.

     Settled solids (from primary and secondary treatment) can be treated
by combinations of thickening, anaerobic and aerobic digestion,  condition-
ing elutriation; or with chemicals,  vacuum filtration and drying on beds or
in kilns.

     The final disposal of wet sludge is accomplished by dumping or piping
it to sea or by incineration; dried or dewatered sludges are also inciner-
ated,  used as soil conditioners, or buried in sanitary landfills.
                                   F-l

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 TREATMENT OF SLUDGE

      The water content of sludge is the controlling factor as to the volume
 of sludge produced.  Sludge can be characterized by the type of process by
 which it was produced.  The following table characterizes sludges produced
 by the various processes.
                               Table F-l

                         SLUDGE CHARACTERISTICS
       Process Producing Sludge
Percent
 Water
Content
Volatile Matter
as Percentage of
   Dry Solids
     Primary sedimentation sludge        94 - 96*

     Activated sludge                    95 - 97.5
        High rate

     Trickling filter                    96 - 97

     Chemical precipitation                95

     Digested sludge (well digested)

       • Primary                         88 - 94
       • Primary and activated           94 - 96
       • Primary and trickling filter    90 - 94
                      70
                    45-70
                    32-45
* Steel, Water Supply and Sewage, pp. 574-575
 The Digestion Process

      Anaerobic organisms break down complex molecular structures of the
 solids and release much of the bound water, while obtaining nutrients
 and energy from the conversion of the raw solids into more stable organic
 and inorganic solids.  Anaerobic sludge digestion takes place in three
 phases:

           •  Acid fermentation.  Soluble or dissolved solids are broken
              down into simple organic acids (volatile acids) with a
              decrease of pH.
                                    F- 2

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          •  Acid regression.  The organic acids and nitrogenous
             compounds are decomposed with an increase in pH.

          •  Methane production.  This occurs simultaneously with
             the first two phases.  Methane bacteria reduce the
             organic acids and other products of the first and
             second phases to produce methane and carbon dioxide gases.

     Sludge digestion accomplishes the following:
          •  Reduces organic matter into simple compounds

          •  Reduces sludge volume
          •  Releases the remaining water more easily
          •  Reduces the coliforms by 99.8 percent in 30 days


Aerobic Sludge Digestion

     This particular process functions in much the same way as an activated
sludge unit, with the feed to the aeration tank being sludge from the
primary and secondary sedimentation basins.  This process requires adequate
mixing and a dissolved oxygen level range of 1.0 to 1.5 mg/1.  The deten-
tion time required for treatment of sludge is from 20 to 30 days with
removals of supernatants and sludge from the digester to maintain a consis-
tent feed rate.
                                     For additional information, see:

                                     Ch. 6, Washington State Treatment
                                       Plant Operator's Manual
                                     Ch. 1 and 7, Eckenfelder-O'Connor
                                     Ch. 14, ASCE STP Design
                                     Ch. 26, Steel
                                     Ch. 12, Imhoff-Fair
SLUDGE THICKENING

     This process, usually found in the larger treatment plants, precedes
digestion, vacuum filtration, or kiln drying.  Sludge thickening is used
to reduce the liquid volume of the sludge solids which have to be pumped
to other treatment units.  These treatment units then can be smaller
because they do not have to handle the excess liquid.
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     There are two major types of sludge thickening operations:
          •  Gravity thickening.   Sludge and aerated secondary effluent
             are introduced into a basin,  much like a stirred sedi-
             mentation basin except deeper,  which allows the concentration
             of solids from flocculation by interfacial contact and
             compaction by the weight of the overlaying water.  This
             method can produce a solids  content of 8% or greater.
             Not all sludge combinations will work in a gravity thick-
             ener,  and testing of sludge produced by the treatment
             process will be necessary.   In some cases, the addition
             of chemical flocculant will aid in the concentration of
             the sludge.

          *  Flotation thickening.  This is usually used on sludges
             formed by biological reactors.   This process combines
             sludge with a liquid which has been exposed to high
             pressure and contains large amounts of dissolved oxygen.
             Under less pressure in the thickening tank, air bubbles
             from the liquid attach themselves to the sludge particles
             and rise to the surface where the sludge is collected
             for further treatment.
                                     For additional information,  see:
                                     Ch.  15,  ASCE STP Design
                                     Ch.  6,  Washington State Treatment
                                       Plant Operator's Manual
                                     Ch.  26,  Steel
                                     Ch.  14,  Imhoff-Fair
SLUDGE CONDITIONING

     The basic processes which are used in sludge conditioning are
elutriation and chemical conditioning.

          •  Elutriation consists of mixing thoroughly 1 part of
             sludge with 2 parts of water and allowing separation
             of about 6 hours,  followed by decanting the resulting
             elutriate and drawing off  the sludge.
          •  Chemical conditioning consists of the addition of cer-
             tain chemicals to coalesce particles in sludge which
             facilitates moisture removal by filtration.  Some of
             the chemicals commonly used are:
                                  F-4

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                        Ferric chloride

                        Ferric sulfate
                        Lime and ferric chloride

                        Chlorinated coppeas
                        Aluminum sulfate

                        Chemical solutions

                        Polyelectrolytes

                        Activated silicates
                        Inorganic polyelectrolytes
                                   For additional information,  see:

                                   Ch. 15,  ASCE STP
                                   Ch. 26,  Steel
                                   Ch. 14,  Imhoff-Fair
SLUDGE DEWATERING

     Some common methods for sludge dewatering are vacuum filtration,
centrifuging,  and sludge drying.

          •  Vacuum Filtration is widely used in the separation of
             liquids from concentrated suspensions, sludges, and
             slurries.   The basic mechanism of this process is the
             passing of a cylindrical drum which rotates partly
             submerged through a container of sludge.  The solids
             in the container are agitated to keep them in suspension.
             A vacuum which is applied between the drum deck and
             filter media causes the water to be removed while sludge is
             held on the filter media.  Following this process, the sludge
             is buried in a sanitary landfill or incinerated.  The
             supernatant can be disposed of by returning it to the
             elutriation tank or returned into the influent of the
             plant.

          e  Centrifuging removes water by centrifugal force which
             tends to force the heavier solids to the outside of the
             rotating flow stream much like the spin dry cycle of a
             washing machine.
          •  Sludge Drying is best suited for sludges which have been
             digested.   The mechanism is that of a shallow sand filter
             for draining the sludge and air for drying in beds.  The
             supernatant may be disposed of in the same manner as
             vacuum filtration liquids.
                                   F-5

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                                     For additional information, see:
                                     Ch. 7, Rich - Unit Operations of
                                       Sanitary Engineering
                                     Ch. 26, Steel
                                     Ch. 15, ASCE STP Design
                                     Ch. 14, Imhoff-Fair
DISPOSAL OF SLUDGE

     The final disposal of sludge is influenced by many factors:

          •  The character and composition of the sludge

          •  Availability of land for dumping of sludge cake or
             lagooning of wet sludge

          •  Whether or not regulatory agencies allow piping (deep
             water sludge outfall) or barging of sludge

          •  Local market possibilities for its use as fertilizer.

     Coastal cities can dispose of sludge through barging or piping
to sea, where still allowed.  On land,  it may be buried in swamps, abandoned
quarries,  and other lands which have no present use.

     Incineration of raw or digested dewatered sludge is gaining popularity.
At present, only larger cities are utilizing this process because of its
added expense.  In general, incineration of sludge is a wet combustion
process in which sludge in solution or suspension goes through chemical
oxidation processes under pressure.
                                     For additional information, see:
                                     Ch. 14,  Rich - Unit Processes of
                                       Sanitary Engineering
                                     Ch. 15,  ASCE STP Design
                                     Ch. 26,  Steel
                                     Short Course - Theory and Design
                                       of Advanced Waste Treatment
                                       Processes, U.C. Berkeley Extension
                                  F-6

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CONTROL   AND
METERING   SYSTEMS

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      7046
                                 Appendix G

                        CONTROL AND METERING SYSTEMS
     Various control and metering systems which are in common use in waste-
water treatment plants are described in this section.   It also indicates the
uses and the limitations of these devices.  The limitations are a function
of physical/chemical makeup of the wastewater,  the type of treatment units
employed, sophistication of the plant personnel, economics, and the plant's
maintenance program.

     A comparison of devices indicated in this  section should be made with
those that will be encountered at the treatment plant  to see if they are
types which will supply the data needed and required to maintain proper plant
performance.

     The section on Problems and Solutions indicated the various problems
which are commonly encountered with existing metering  devices to help with
solutions.
CONTROL SYSTEMS

     Wastewater treatment plants use a variety of treatment processes.
These processes usually fall into four categories: physical, biological,
chemical, and electrochemical.  In most plants, the processes are affected
by temperature, weather, and day-to-day load variations.   The nature of
wastewater being high in solids' content and the inability of sensors to
withstand fouling due to these solids makes total automation (computer
control of the process) infeasible at the present time.

     Most treatment plants in  existence today use instrumentation which
involves the measurement of physical variables, such as  flow, level,
pressure, and temperature.  These controls are electric  and pneumatic
mechanisms in conjunction with hydraulic equipment.  These controls can be
divided into two basic types:

          •  On-off - used for the activation of pumps,  alarms, etc.

          •  Modulating - where the regulation of valves  or other
             equipment is accomplished in proportion to  a measurement
             (ratio control).

     The treatment systems utilize these controls to regulate or determine
recirculation rates or controllers that set recirculation flow at a ratio to
some other variable.  The greatest present use for instruments and controls
is in the treatment of sludge, where the use of density monitoring equipment
to maintain optimum raw sludge density in the digester is becoming common.
                                     G-l

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TTP^I  7046
Other examples of automated control include: temperature control, gas volume
sampling, and sludge level measuring equipment.

     What most systems lack is redundancy;  there are no built-in back-up
systems for emergency failures.  A second shortcoming is the lack of an
information feedback system.  If a switch on the operating console activates
a pump, there is no return loop which indicates to the operator that the
pump has in fact been activated and is working.
FLOW MEASUREMENT


Differential Measuring Devices and Instruments

     Devices which measure flow and are used with differential measuring
instruments are all descendants of the Venturi tube and are considered pri-
mary devices.  Most of the devices require very little head and can handle
flows which contain suspended solids.   Larger differential (high-head
recovery) devices, such as the Ball tube, amplify a small, purely static
change in head to a value which can be conveniently measured with secondary
instruments.  The high-head recovery,  Venturi-type devices are not applicable
to "dirty" fluids (high solids content) except in conjunction with a purging
system.  Other exceptions are the flow nozzle and the Lo-Loss tube.

     Orifice plates were originally developed for use on gas flows, but have
been applied for use in the masurement of water which contains little or no
solids in suspension.

     In general, wastewater can be successfully metered with the long- and
short-type Venturi tube, flow nozzle,  and Lo-Loss tube.  It must be realized
that an orifice that is too small produces large permanent pressure drops
and is uneconomical.  On the other hand, a too-large orifice measurement can
be affected by inlet flow disturbances.  The choice of device has to be care-
fully considered.
Secondary Instrument System

     These instruments measure the differential produced by the primary
devices and convert the result into a signal for transmission or into a
motion for indication recording or totalization.  These instruments include
mercury manometer, diaphragm meter, and various types of force-balance and
motion-balance pneumatic and electronic transmitters.
Other Flow Metering Devices

     •  Magnetic devices utilize Faraday's Law to measure flow in a
        magnetic field.  With a steady magnetic field, the volume of flow
                                    G-2

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      7046
        rate is directly proportional to the generated voltage;  a voltmeter
        calibrated in volume flow units is then read for the  flow measure-
        ment.   The basic advantages:  it has no head loss;  it  handles  solids
        in suspension; it has no liquid connections; and it has  an electronic
        output ready for in-plant transmission.
     •  Propeller meters utilize the  velocity head and convert  it into
        mechanical power which is linear and translatable into  velocity.
        This type of system is useful where frequent totalization readings
        are necessary.
     •  Open Channel Devices -
          Weirs are of two basic types: rectangular and V-notch.   In  weir
          measurement water abruptly  flows through a precise  cross section.
          The nappe, or profile of water over the weir, must  be  completely
          aerated in order to have precise flow measurement with a minimum
          head loss.
          Flumes , a modification of the basic weir concept,  are  designed
          primarily to reduce head loss that occurs in weirs.  This is
          accomplished by having the  sides of the channel vary  gradually
          to the desired cross section.
          Open-channel flow nozzle is a combination of flume  and weir;
          this device can handle solids effectively but does  not have the
          head recovery characteristic of the in-line flume.

     In general, the flow-through of  a weir- or flume-type device is  a
function of fluid level.  The three basic devices for measuring this  level
are float-and-cable, the in-flume float, and the bubble tube.

     In determining if the type of measuring device is suitable for the
location in the treatment system, the following should be considered:

          •  Probable flow range

          •  Acceptable head loss

          •  Required accuracy
          •  Fouling ability of wastewater

     The diversity of instruments for measuring the various parameters
precludes their individual description in a broad overview.   The level of
sophistication of these instruments is rapidly increasing.  Devices which
are available and are used for pressure, level, temperature,  and analytical
measurements consist of:

          Pressure

          •  Bourdon tube
          •  Spiral and helical elements
                                    G-3

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7046
    •  Bellows and diaphragm elements

    •  Wire strain gauges

    Level

    •  Bubble tube

    •  Diaphragm box

    Temperature

    •  Mechanical (filled  thermal)  system

    •  Electrical systems
    Analytical Measurement

         Type of Measurement
         •  pH; oxidation-reduction
            potential (ORP)  (although
            many ions can be measured
            with selective  ion
            electrodes)

         •  Residual chlorine; DO
         •  Turbidity;  color

         •  Conductivity
Type of Electrical Signal
   Voltage or amperage

   Amperage or resistance
   Resistance
                                       For  additional  information,  see:
                                       Instrumentation and  Control  in
                                        Water Supply  and Wastewater
                                        Disposal  by Russell H. Babcock,
                                        P.E. ;
                                       Introduction to Chemical Process
                                        Control by Daniel  D.
                                        Perlmutter;
                                       Ch.  19,  ASCE Treatment Plant
                                        Design;
                                       Ch.  11,  Operation of Wastewater
                                        Treatment Plants,  EPA.
                               G-4

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H

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MAINTENANCE
DATA  SYSTEM

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                                Appendix H

                            MAINTENANCE DATA
      This section of the manual describes the basic components of a main-
tenance system.  It describes the type of filing system which could be
employed for maintenance data, how to set up such a filing system, and the
type of  information it should contain.

      By comparing the maintenance records at the treatment plant with this
guide and manufacturer's maintenance schedule,  the plant's maintenance pro-
gram can be evaluated.

      It is imperative that a record be kept of the service requirements of
every piece of major equipment in the plant and when and how frequently
service is required.  Therefore, a system is needed to keep a complete record
of maintenance requirements.  Such a system should provide a permanent record
of all maintenance work together with the advanced scheduling of preventive
maintenance for an entire year.  The system should also provide the maintenance
work schedule for any given day.  To be efficient,  the system should contain
the following five files:

      (1) preventive maintenance records

      (2) the preventive maintenance schedule for each piece of
          equipment

      (3) specifications on each major piece of equipment, the
          supplier, and where spart parts can be purchased,

      (4) spare parts inventory, and
      (5) instructions for operation and maintenance of each item
          of major equipment.

      As a first step in setting up any maintenance record system, each struc-
ture and each major piece of equipment should be assigned a file number.  A
simple means of doing this is assigning each area or each structure within a
treatment plant a block of 1000 numbers; and each equipment item in each area
or structure requiring maintenance can be assigned an individual number within
the block of 1000.   Therefore, sufficient open numbers remain to provide for
any additional equipment which may be required within that area or structure
in the future.  The assigned numbers will serve to identify each item of
equipment in all of the plant records described above and should also be used
to catalog spare parts.

      The file of preventive maintenance requirements mentioned in Item 1
above should contain one sheet for each item of plant property which
requires periodic attention or maintenance,  filed numerically.   Listed
thereon should be all pertinent requirements with respect to periodic

                                    H-l

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GOB
 maintenance including frequency,  number of men required,  and the estimated
 time of performance.  These sheets are to be filed numerically as recommended
 above and maintained as a reference file.

       The file for preventive maintenance scheduling as mentioned in Item 2
 above should show the equipment number and the key information given on the
 preventive maintenance sheet,  together with a specific day for the performance
 of each item of work.  Space should be provided on each equipment card for the
 operator to know the work items performed and the date of performance.  A
 systematic means of pulling these cards on the dates on which maintenance
 work is required should be devised.

       The equipment data file mentioned in Item 3 above should contain cards
 with complete nameplate data for each item of equipment.   These cards may
 also be used to show the type of lubricant required, together with the nature
 of any special service requirement.  The cards should also be filed numeric-
 ally in accordance with the recommended system.

       The operation and maintenance instruction file mentioned in Item 4
 above should contain information relating to maintenance,  operation, and
 servicing of each item of equipment.  This information should be filed numer-
 ically in accordance with the recommended system.  Specifically, the file
 should contain all maintenance and operation manuals furnished by equipment
 manufacturers, parts lists,  dimension drawings, and other informative
 literature.

       In order to maintain an effective maintenance program it is recommended
 that the maintenance record system be kept up to date faithfully and consist-
 ently.  Service requirements should be modified as equipment ages and flow
 rates increase.  All modifications to major plant equipment should be
 recorded in the maintenance record system.

       A complete set of the as-built drawings of the wastewater treatment plant
 should be available for the ready use of the plant operators.  The plant
 operators should record on these plans all changes that are made in the
 plant piping, equipment,  and electrical circuitry.  The original drawings
 of the treatment plant should be updated at least yearly in accordance with
 the changes made on site.
                                        For additional information,  see:

                                        Ch. 11,  Operation of Wastewater
                                          Treatment Plants,  EPA.
                                     H-2

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REFERENCE

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REFERENCES

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                                 Appendix J

                                 REFERENCES
 1.  Advanced Wastewater Treatment Seminar,  Session I to III and
     Section IV, October 1970.

 2.  'Aeration Plants  in  Florida,"  ASCE Journal of Sanitary Engineering,
     Vol. 88, SAG, November 1971.

 3.  Agardy, F.J., and M.L.  Kiado,  Effects of Refrigerated Storage on the
     Characteristics  of  Waste,  21st Industrial Waste Conference, Purdue
     University, 3-5  May 1966.

 4.  Babcock, Russel  H.,  Instrumentation and Control in Water Supply and
     Wastewater Disposal,  R.H.  Donnelley Corp.,  1968.

 5.  Gulp,  Russell and Gordon  L.,  Advanced Wastewater Treatment, Van
     Nostrand Reinhold Environmental Engineering Series,  1971.

 6.  Eckenfelder, W.W.,  and D.J. O'Connor,  Biological Waste Treatment,
     Pergamon Press,  1961.

 7.  Fair,  Gordon M. , John  Geyer,  Water Supply and Wastewater Disposal,
     John Wiley & Sons,  4th edition,  1961.

 8.  Fair,  Gordon M. , John  Geyer,  and Daniel A.  Okum,  Advanced Waste
     Treatment,  Research Series, AWTR-2 to 12,  1962-1964"!

 9.  "Field Evaluation of the  Performance of Extended Aeration Plant,"
     WPCF,  Vol.  41, July 1969,  p.  1299.

10.  Imhoff, Karl, and Gordon  M. Fair,  Sewage Treatment,  John Wiley &
     Sons,  2nd edition,  1956.

11.  Operation of Wastewater Treatment  Plants,  A Field Study Training
     Program, Environmental  Protection  Agency,  Office of  Water  Programs,
     Division of Manpower and  Training,  1971.

12.  Perlmulter, Daniel  D.,  Introduction to  Chemical Process Control,
     John Wiley & Sons,  1965.

13.  Rich,  Linvil G.,  Unit Operations of Sanitary Engineering,  John Wiley
     & Sons, 1961.

14.  Rich,  Linvil G.,  Unit Process  of Sanitary Engineering,  John Wiley  &
     Sons (to be published 1972).
                                     J-l

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15.  Sawyer, Clair, "Final Clarifiers and Clarifier Mechanisms,"
     ASCE STD, MIT, 1962.

16.  "Sewage Treatment Plant Design," ASCE Manual of  Engineering  Practice,
     No. 36, WPCF Manual of Practice No. 8, 1959.

17.  Short Course - Theory and Design of Advanced Waste  Treatment
     Processes, University of California Extension, Berkeley,  Calif.,  1971,

18.  Standard Methods for the Examination of Water and Wastewater,  13th
     edition, APHA, AWWA, WPCF, 1971.

19.  Steel,  Ernest W.,  Water Supply and Sewage, McGraw-Hill, 4th  edition,
     1960.

20.  Waste Heat Utilization in Wastewater Treatment,  URS 7032,  URS Research
     Co., San Mateo, Calif.,  (to be published  1972).

21.  Waste Water Plant Operators Manual, Coordinating Council  for Occupational
     Education, State of Washington, Division  of Vocational  Education.

22.  Wastewater Treatment Plant Operator Training Course Two,  WPCF No.  14,
     1967.
                                    J-2

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GLOSSARY

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GLOSSARY

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     7046
                                Appendix K
                                  GLOSSARY


     The terminology used in the glossary of this manual reflects particular
meanings of those words and definitions which clarify the basic informa-

tion compiled from the various texts, journals and technical papers used.
BIOCHEMICAL
OXYGEN
DEMAND
(BOD)
BIOLOGICAL
OXIDATION
The quantity of oxygen used in the biochemical oxidation
of organic matter in a specified time, at a specified
temperature, and under specified conditions.  It is
not related to the oxygen requirements in chemical
combustion, being determined entirely by the availa-
bility of the material as biological food and by the
amount of oxygen utilized by the microorganisms
during oxidation.

The process whereby living organisms in the presence
of oxygen convert the organic matter contained in
wastewater into a more stable or a mineral form.
BY-PASS
CHLORINE
CONTACT
CHAMBER

CHLORINE
DEMAND
COMBINED
AVAILABLE
RESIDUAL
CHLORINE
A pipe or conduit which permits wastewater to be
moved around a wastewater treatment plant or any unit
of the plant.  This is usually found in plants which
receive combined flow or high infiltration rates
and is utilized to prevent flooding of units, or in
case of shutdown for repair work, flow can be moved
to parallel units.

A detention basin where chlorine which has been dif-
fused through the treated effluent is being held a
required time to provide the necessary disinfection.

The difference between the amount of chlorine added to
the wastewater and the amount of residual chlorine
remaining at the end of a specific contact time.  The
chlorine demand for given water varies with the amount
of chlorine applied, time of contact, temperature,
pH, nature and amount of impurities in the water.

That portion of the total residual chlorine remaining
in water or wastewater at the end of a specified
contact period which will react chemically and
biologically as chloramines, or organic chloramines.
                                     K-l

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 "pEj 7046
COMBINED
RESIDUAL
CHLORINATION
The application of chlorine to water, wastewater, or
industrial wastes in an amount to produce directly
or through the distribution of ammonia, or of cer-
tain organic nitrogenous compounds, a combined
chlorine residual.
COMBINED
SEWER
SYSTEM
A transport system which carries both sanitary
wastewater and storm or surface water runoff.
DENITRI-
FICATION
EFFLUENT
ENDOGENOUS
RESPIRATION
FOOD
TO
MICROORGANISM
RATIO
HYDRAULIC
LOADING
INFILTRATION
INFLUENT
MIXED
LIQUOR
Chemically-bound oxygen in the form of either nitrates
or nitrites is stripped away for use by microorganisms
This produces nitrogen gas which can bring up floe in
the final sedimentation process.  It is an effective
method of removing nitrogen from wastewater.

Wastewater or liquid - raw, partially or completely
treated; flowing from a basin, treatment process,
or treatment plant.

An auto-oxidation of cellular material  that takes
pla'ce in the absence of assimilable organic material
to furnish energy required for the replacement of
worn-out components of protoplasm.

An aeration tank loading parameter.  Food may be
expressed in  pounds of suspended solids,   COD,
or BOD added per day to the aeration tank,  and
microorganisms may be expressed as mixed liquor
suspended solids (MLSS) or mixed liquor volatile
suspended solids (MLVSS) in the aeration tank.  The
flow (volume per unit time) applied to the surface
area of the clarification or biological reactor
units (where applicable).

The flow (volume per unit time) applied to the
surface area of the clarification or biological
reactor units (where applicable!

Groundwater that seeps into pipes through cracks,
joints,  or breaks.

Wastewater or other liquid - raw or partially treated;
flowing into a reservoir, basin, treatment process
or treatment plant.

A mixture of activated sludge and wastewater under-
going activated sludge treatment in the aeration tank.
                                    K-2

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    7046
ORGANIC
LOADING

OVERFLOW
RATE
OXYGEN
UPTAKE
RATE

POSTCHLORINATION
PRECHLORINATION
RAW SLUDGE
RECIRCULATION
RATE

SANITARY
SEWER
SYSTEM
SLOUGHINGS
SLUDGE
AGE
Pounds of BOD applied per day to a biological reactor

One of the criteria for the design of settling tanks
in treatment plants; expressed in gallons per day
per sq ft of surface area in the settling tank.

The amount of oxygen being utilized by an activated
sludge system during a specific time period.
Application of chlorine to the final treated wastewater
or effluent following plant treatment.

Chlorination at the headworks of the plant; influent
chlorination prior to plant treatment.

Settled sludge promptly removed from sedimentation
tanks before decomposition has much advanced.  Frequently
referred to as undigested sludge.

The rate of return of part of the effluent from a
treatment process to the incoming flow.

A sewer intended to carry wastewater from homes,
businesses, and industries.  Storm water runoff
sometimes is collected and transported in a separate
system of pipes.

Trickling filter slimes that have been washed off
the filter media.  They are generally quite high in
BOD and will degrade effluent quality unless removed.

In the activated sludge process,  a measure of the
length of time a particle of suspended solids has been
undergoing aeration expressed in days.  It is usually
computed by dividing the weight of the suspended
solids in the aeration tank by the daily addition of
new suspended solids having their origin in the raw
waste.
SLUDGE
DENSITY
INDEX
A term also used in the expression of settling
characteristics of activated sludge 100/S.V.I.
                                    K-3

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    7046
SLUDGE             A numerical expression of the settling characteristics
VOLUME             of activated sludge.  The ratio of the volume in
INDEX              milliliters of sludge settled from a 1000 ml sample
(SVI)              in 30 minutes to the concentration of mixed liquor in
                   milligrams per liter multiplied by 1,000.

SUSPENDED          Solids that either float on the surface of, or are in
SOLIDS             suspension in, water, wastewater, or other liquids,
(SS)               and which are largely removable by laboratory filtering.

WASTED             The portion of settled solids from the final clarifier
SLUDGE             removed from the wastewater treatment processes to
                   the*solids' handling facilities for ultimate disposal.

WET                A compartment in which a liquid is collected and held
WELL               for flow equalization and then pumped (by systems'
                   pumps for transmission through the plant).
                                    K-4

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