PROCEDURES FOR EVALUATING

PERFORMANCE OF WASTEWATER TREATMENT PLANTS

A Manual
Prepared for


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

Under Contract No. 68-01-0107
by

URS RESEARCH COMPANY
Environmental Systems Division                    •••Qj
San Mateo, California 94402

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ABSTRACT
This manual establishes a procedure for the
evaluation of the performance of wastewater
treatment plants.  Jt 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.
                     111

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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 described.  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.
                                     1

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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
1 :

1/2
2* J

0 to 3
1

100
Lj to 2^

1 to l£
l\ to 4

0 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
             (BODg,  pH,  001} 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,  BOD,-,  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-Visit 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. .^ tf&U&UM X*^

     Problem identification begins wifrfa k 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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 DDE
            •  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 f j.rst 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 wtiich 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.
         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?	
Background Informatic
      1.   Type of Plal
          Schematic oj
          Contributor]
                Domestl
                  •obtain prior to visit
2.
3.
Low Route to Unit
jpulation
                Industrial (P
                Other
     4.   Type of Wast]
                Combii
                Saniti
                 iwa'
                Indus
      5.   Geographic
               Clin
 ftic Effects
           ,o
                            Ranges ( F)
                Rainfall Extremes (in.)
                                           to
                                           to
                                      11

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6. Plant Wastewater Characteristics
                         Nitro-
                         gen
                                             Sus-
                                            pended
                                            Solids
                                            (mg/£)
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/g^M^ITting reports

         b.Identified from/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
 Lsting
>lant
Values
                                         Loading Rates
Design and/or
 Recommended
Manual Values
3.  Historical Operational Data
            Organize data 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
Treatment
Type

Pests Perfo
; System Ev
Frequency

rmed/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 BESTING PROGRAM
         •  Are the sa noting locations suitab
            Are testin j procedures
            Is testing
            process co
                    equency adequ
                    ol?
III.   LABORATORY FACILI
            Is the labofra\pry
            apparently fun\tio
            Is there enough
            all the nefessarj
            Is the eq
                              irgdfiized and
                              is intended?
                             knt to perform
                            3tS?
                         eing properly used?
IV.
PERSONNEL - Planf Operators (including lab personnel)
       Is the st^t^eKiequate in size?
    •  Are theyfqualified?   State certified?
    •  Is thera 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 performs
            be improved by simple and/or inexper
            changes?
                                                                    Yes
                         No
Evaluator:  If any of'
            taken:
         1.  Submit a
              •  Sumnu
              •  A lis
              •  Solu^
              •  Prop^
         2.  Discuss
             plant s1
                          answers are
ollowing steps should be
                                    Ivisit
                                bins encountered
                      lions! rqqMmended
                           ctlon.
                           ^commendations with treatment
             In cooptJtaf ion with the plant operator  (and  local
             officials, if necessary), decide on a course of
             action fo solve the problem(s).
             After af suitable period of time, revisit the
             plant fo 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- Aeration

Sedimentation
Primary sedimentation
before activated sludge
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
Chemical Precipitation

Chlorination S/
Type of wastewater or
effluent :
Raw wastewater, depending
on strength and stale-
ness
Settled wastewater
Chemically precipitated
wastewater
Trickling filter effluent
Activated sludge plant
effluent
Intermittent sand filter
effluent
Operational ^ ^^
Parameters
2/
Bar Spacing in Inches—
1-2
1/2 - 1
1/32 - 1/4
As small as 5/8 -
Flow Velocity: Mteh of Gritf Overflow Rate
0.75 to to\Be Removed gal/sq ft/ day
1.0 ft/sec \35 / 73,000
\g/ 51,000
sX 38,000
V"0\ 25,000
/ Ai^j Requirement :
/ .025 to .05 cu ft/gal
Capacities: , /
0.35 to 25 MGD- _*— — — — —
650-5,200 lb/hr£ 	 ,. 	 *~"~*
Detention Time: Air Requirement: I/
15-45 min. .005 to .2 cu. ft/gal
or 25 - 40 psi
Overflow Rates: I/
2000-6000 gal/day/sq.ft
2/
Detention Time- Overflow Rates
(hr) gal/day/sq ft
0.75 - 1.0 1,500 - 1,000
2.5 600
2.0 - 2.5 600 - 900
2.0 1,000
2.0 800
2.0 800
2.0 800
Weir loading rates:
*-l MGD; 10,000 gal/linear f t -
>1 MGD; 15,000 gal/linear^f t
\
2/
Chlorine Probable Chlorine Chlorinator—
residual : Requirements Capacities
2 mg/1 Ib/day
„ ^ ^ _ mg/1 per 1,000 mg/1 lb/1,000
Contact time : -
persons * persons *
6-25 5-21 30 25
5-20 4-17 25 20
3-20 3-17 25 20
3-20 3-17 25 20
2-20 2-17 25 20
1-10 1-3 15 12
Accumulated Material
(Sludges, etc. )
I/
Cubic feet/MG
3/4 - 3
3-8
5-30
Cubic feet/MG
2-8


Volume of skimmings:
0.1 to 6 cu.ft/MG
or 200 cu.ft/
1000 person/yr
Sludge accumula-
tion is approxi-
mately .038 cu ft/
capita or 3,500
gal/mg of flow
sSludge contains
chemical high water
conteiffc^nd is twice
the volumexproduced
from plain sedi-
mentation ^^^
Scum and grease
accumulated in
contact chamber.
Support Systems
Power for mechanically
cleaned racks,
conveyor belts,
grinders
Power for mechanical
cleaning, cyclone
operations, and for
pumps to supply air.
Conveyor system to
remove grit.
Power :
"•""iTi to 3.5 hp motor
Cleaning units for
dif f users, 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.
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 t
xOperat ionaV— >~^^
t^'S ' Parameters-^ ^N,
y
' Recirculation Rate for
Maximum BOD of Settled
Wastewater
\
\
Loading Rates
Low Rate
gal/day/sq ft 25-100

High Rate
Filter
200-1,000^
Support Systems
= 	 -\
v Dosagin£>tanks
                                     -Recirculation
                             BOD mg/1      Ratio
                               130          1:1
                               170          2:1
                               220          3:1
                               260          4:]
                                                  '  million gal/acre/day  1.1-4.4
                                                   Organic Loading
                                                    lb/1,000 cu ft/day    5-25
                                                    Ib/acre ft/day     220-1,100
 8.7-44      >elcjfc>e'pui
            power supply
  25-300
,100-13,000
Intermittent Depth of sand 3J-4 ft
Sand Filters Head on filter, 5 ft
Stabilization Pond
or Lagoon^ Detention Concen- 4/
1. Large holding reservoir (days)** Depth tration —
- -tabili-ntion oond (months) (ft) (mg/1)
(a) Facultative 7-30 2-5 10-50
(b) High rate 2-6 J-l 100
3. Aerated lagoons 1 or 2 - 14 6-15
4. Anaerobic 30-50 8-10
Final clarification
Following
Low-rate trickling filters
High-rate trickling
filters
Activated sludge (over
2.0 mgd)
Activated sludge (under
2.0 mgd)
Loading 75,000-125,000
gal/acre/day
Solids 2 lb/5 sq ft/day



Ib/acre/day
20-50
100-200

300-500
Overflow Data 3 g/
gals/day/sq ft — *~
800-1,000

800 /"Vs.
*-**T j
800-1,000 ^— ^

800
C Dosing siphon of )
flow distributor )
~





Aerators


Sludge pumps, power
supply for mechanical
sweepers , pumps
reclrculatlon pump



                            Detention Tine (hrs)  for
                          Overflow Rates & Depth  of Tank—'
Overflow Rate Depth ^*^
600 2.1 2.4 3,/0


Package Aeration
Plants

800
1,000

Flow Rate :

1.6 1.8 .X2.25
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 & ponds
(see table)
For background information see App. D.
Unless  otherwise noted
                                                  I/  Now parallel  systems
                                                  £/  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
Tyjjes of Process
Table II-3 I —
In
QPTTYNTIA DV TPITATTWITTMT HATA APTY VATTTn QT ITnm? OPHP'C'QQ " -

Operational Parameters Loading Rates Support Systems
2/ Loading-
Detention Time- Percentage Recycled Ibs BODs/
Type of Mixing Flow Scheme (hr) Sludge Ibs MLSS Air Requlrements-
Plug Complete Aeration Aeration & Uulti Stage
Flow Mixing Only Sludge Return Aeration
& Sludge
Return
Modified Aeration
(or high rate)
Conventional
Contact Stabilization
scheme 1
scheme 2 A
tO PWO Stage Aeration I
Extended Aeration
Step Aeration
x x 3 or less 10-sc£ 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
x x .5-1.0 50-1502/ 1 0.15-0.2 \ (750 ft3/lb BOD 'N P°wer s"PPly
x x Contact range 1-4 1 0.15-0.2 \ V removed / sludge pumps
Stabilization tank ] \ ^^» 	 ^S air compressors
-^ ' ^-^^^.^ ™~ ~" alr control
x x Contact range f 0.07-0. 15% system
1.5-3.0 \ ^^^a&' sludge
Stabilization tank v— — __— — aeration
f 6-9 ^__ 	 tanks
x x 24 hr 50-200- C /*0. 01-0. 07 •* J
3-8 20-7^ .2-0.5 of /tf500-700/f t3/lb 1\
50 Ibs/lOOOft3 V^TjaDD^removed J
Completely mixed 3 or more 20-10O- 2-.5 C./ SOOft^lbTOD )
Oxidation Ditch (Passover Ditch) Due to limited data at this tine, no ranges for operational parameters or loading rates are possible.
I/ Ib of BOD Ib mixed
liquor 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  air/lb BODs  except extended aeration which Is 2000
4/ Steel
5/ 10-State Standards, 1971

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

-------
                                                   Table I1-4

                                       ADVANCED WASTE TREATMENT DATA*
                                                                                                          ffl
V
 X
      Unit  Operations
        or  Processes
                        Operational  Parameters
                                                 Accumulated Material
                                                          Support Systems
\VV^\ Chemical/Physical
    If     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
on
Ammonia
     Stripping
Air temperatures above
32°.  pH between
10.8 and 11.5
                                                        Ammonia  is  carried off
                                                        into  atmosphere.
                                                    AJ2-- Soma  carbonate scale
                                                        ind sludge  buildup.
                                                                                   Power for forced draft.
                                                                                 A Coupling with
                                                                                   phosphorus removal.
                                                                                   Recarbonation equipment
     Electrodialysis
                     Flow rate: up to
                     10 MOD.  More
                 A  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  I1-5
                                                        *
                                       SOLIDS TREATMENT DATA*
                              Operational
                              Parameters
                                                                                        Support Systems
      Unit Operations
       or Processes
                                       6.8-7.2
                                       85-95°F
                                       30 days
                                       12 cu ft/lb
                                       volatile
                                       matter
                                       reduced
Anaerobic
Digestion
PH
Temperature
Detention
Gas production
                                                                                       Heat  exchangers
Loading of Heated
Tanks,** Ib volatile
solids per cu ft
   per montj
Circulation pumps
                                                                                       o  Gas
                                                                                       o  Sludge
Sludge produced/ for
Anaerobic Digestion by

  Plain sedimentation
Plain sedimentation
and trickling
fi>tfatlpn """"^-^
f Low-rate operation \
V High-rate operation *

and activated sludge
High-rate operation
Conventional operation
Aerobic
Digestion
Sludge
Thickening
Gravity thickener
o Secondary sludge
o Activated sludge-
Flotation
Sludge Drying
Beds for:
o Primary precipitation
o Standard-rate filter!/
o High-rate filter 2/
o Activated sludge!/
o Chemical precipitation
#-' r/s
fjS 9 9
£ 4.4 9
3.6 7
Dissolved oxygen 1.0-1.5 mg/1
Detention times 20-30 days
Overflow Loading
gal/sq ft/day Ibs/sq ft/day
400 8
500 8
Area in sq ft per capita
Open beds Covered beds
1.00 0.75
1.25 1.00
1.50 1.25
1.75 1.35
2.00 1.50
QLG4. -JjJtLvLMA.
U ' »irv4j
<^Ju
-------
CO
o
                                                         Table  II-6

                                              COMMON  SOLIDS TREATMENT DATA*
ffl
Amounts of Chemicals Commonly
Unelutriated Sludge and Yields
Condi-
tioner,
% of
dry
sludge
solids
Type of Sludge CaO FeCl
O
Plain sedimen-
tation (primary)
1. Fresh sludge 10 3
2. Digested
sludge 10 2
0 6
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
5. Fresh activated
sludge 0 6
6. Fresh settled
sludge mixture 0 6
7. Digested mixed
sludge o 8
Dry
Solids
Ib per
1,000
persons
daily
143
89
78



183
117
99





71
195
129
Filter
Capacity
Ib per
sq ft per Cake
hr, dry Solids
basis %
5 32
6 32
6 28



4 28
6 30
6 26





2.5 20
4 22
2.5 22
Employed in
of Vacuum
Required
Filter
Area, sq
ft per
1,000
persons
daily
1.2
0.6
0.5



1.9
0.8
0.7



fl
I D
1.2 *^
2.1
2.1
Conditioning
Sludge Filters
Condi-
Sludge tioner,
Cake, Ib per
Ib per 1,000
1,000 persons
persons daily
daily
450
280
280



650
390
380





350
880
580
CaO FeCl,
O
12 3.6
7.5 1.5
0 4.5



18 4.4
11 1.9
0 6.7





0 4.1
0 11
0 9.7
Support System
Dosing equipment
Power supply
Sludge pumps
Elutriation
tanks
Chemical
storage












       *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

        »  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
/                (j/4X^us/tf"1   '   '          <--^                      w-  yjjr.  ^ur*
    The characterization of waste, whether it be domestic or industrial in  J ju^  ^
origin, beg_inswithsampling.  A wastewater treatment plant consists of
various components which make up the treatment system.  A program of
sampling and testing which measures influent, effluent and'individual
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.      ^^ \)
-------
facilities.  The treatment plant should be provided with adequate laboratory
facilities for the performance of tests necessary for the proper operation
>f 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
A/&A/VAJ
aA
)°£ii AI/W
Removal f
^
• P R I
y
/ Primary
Sedimentation


TEST l %J),4 
-------
                                                "»

                                 Table III-2
                          EQUIPMENT TESTSSG MATRIX*

                  EQUIPMENT NEEDED  •*	
* '11
r ^Y* 4
CONSTITUENTS 'tt| ^J
TO BE ANALYZED U ^
\ Volatile Solids
I Total Solids
' ^Settleable Solids
Total Sulfides
< Biochemical Oxygen Demand
Chemical Oxygen Demand
•^ Suspended Solids
Dissolved Oxygen
*X Chlorine Residual
ell-fa'* W 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
f—t~erc~ —
^hSfheTms—
Calcium Content
Ammonia Nitrogen
Organic Nitrogen
Nitrate Nitrogen
Heavy Metals

/ «J
Atomic Absorption.
600° C Muffle Furnace
103° C Drying Oven
Analytical Balance
Imhoff Cone 3
• • •
• •
•



• •






• •


• • •



• •

•


•



•
A-^ ^
* ^ Is
V i }; ~4
\ O t» C
fc .5 £ J -s
co v_J LO i; co





•



'•#'

•
•
•
















i.
Turbidity Meter
Carbon Adsorption Unit
Desiccator
Spectrophotometer ,3
OHlllny CHuiuiiicnt U&^t. U^t-
•
•




•








•
•

•


«


_.
" .


•

"*: S
^^
^ t"
I!
1 | | 0




• •
• •




• •



•







•







*The equipment specified in this matrix is  subject to plant size and com
 plexity of processes and  the  degree  of

-------
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  composit
            sample isn't masking extreme conditions of  the—was
                                                        /''/y  \
            It is also used when test samples cannot b^ inaxedj such
            as when testing for residual chlorine, dis^soi-vea 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 flo,w or the same amount
            being collected at every internal during the sampling
            period.  Composites^ should bo/corrected as  specified in
            Standard Methods.
Location of Sampling Points
                                 •  '                 >            -n.
                                                                     J ^
    Samples should be taken only jfhere the wastewater  is well mixedM  \t
large particles are found in the/sample, they should be broken up  to make
a more homogeneous sample.  Dejrosits or growths of floating material
which have formed at the samRiing point should not be  included in  the
sample.
Quantity of Sample
                                          ^,

    In order to determime 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 thar quantity of sample needed for analysis; 1  liter is
usually sufficient; never try to work with less than about 200 ml.

Handling and SJrorage of Samples
    Samples sfhould be tested as soon as possible.   If testing must be
delayed, th/n adequate storage must be provided.  Table  II1-3 recommends
appropriatiS storage temperature and duration in terms of  the test to be
performed/on the stored sample.
                                    35

-------
                                Table II1-3
                      STORAGE TEMPERATURE AND TIMFP
                                                  I/
ANALYSIS
Total solids
Suspended solids

Volatile sus-
pended solids
COD

BOD
TEMPERATURE
4°C
4 C

4°C



TIME/
/
Up /o
several
d/ays
/Up to
several
days
Up to
several
days
Up to one
day in com-
posite
sampling
systems
TEMPERATURE
<^
0°C f

o°c
o°c


TIME
f^l
No storage

No storage
Unlimited

Lag develops,
must use
fresh
sewage
seed
Source: Agardy,  F.J.,  aria M. L. Kiado, Effects of Refrigerated Storage on
        the Characteristics of Waste, 21st Industrial Waste Conference,
        Purdue Univer/ity, 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
                                     MDP 18
                                    37

-------
                                                                                 SAMPLING  PROGRAM  FREQUENCY  AND  LOCATION
                         PARAMETERS TO  SAMPLE
PROCESSES
PRE TREATMENT
GrU Removal
PRIMARY TREATMENT
Sedimentation
SECONDARY TREATMENT
Activated Sludge
Trickling Filler- Single Stage
Trickling Filter -Two Stage
Oxidation Ponds
Final Sedimentation
Package Aeration Plants
Imhoff Tanks
DISINFECTION
Chlorination
SOLIDS HANDLING
Thickening
Digestion
Centrifuging
Vacuum Filter*
Incineration
ADVANCED WASTE
TREATMENT
GREASE

©®*

,












See Tab
See Tafal
I
a.

©©»•

mm,
©o
©d
©d
©©©„

©©"
©<
@®»


©<


, Ml-l.
e Ill-l.
1

-t
©d
©d
©G@d
©@"
®-
©y
/







O
§

©O".






©"













I








©-









CHLORINE RESIDUAL

®d

®.'



©d

©d
©d
©d






FREQUENCY
       daily   d
     weekly   w
     monthly   no
    biweekly  b-w
   bimonthly  b-m
     when in
    operation    q
SAMPLING POINT
    Q  raw sewage
    (2)  final effluent
    ^  proceo effluents
    @  primary effluent
    (V)  secondary effluenl
                          NOTE: Thi* ii a minimum
                                 channel with plant
:diote effluent
®  i»l
©  c(orifi«d efflu«i
®/filt.red effluent
      .fluent
r®  inlluent or .Fflu.nl
                          ing program and U subject to
                           ind operational problemi.
^§) digestor effluent
© row.ludo.
(Tg) primary sludge
(f|) secondary sludge
© above tludge blanket
                                            Qj)  digested sludge
                                            @  receiving water
                                            
-------
                      SAMPLE FORMS  TO BE USED WITH
                A SAMPLING AND TESTING PROGRAM ANALYSIS
                             AND EVALUATION
Forms to be developed and 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                          ^—•66-
     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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VACUUM FILTERS
     LowOsolids
                  cove]
INCINERATION
     Abnormally high temperature in furnace
     Abnormally low temperature in furnace
     High oxygen level in furnace stack exhaust
     Low oxygen level in furnace stack exhaust
SLUDGE LAGOONING
     Excessive solids carried over from lagoon
         supernatant to plant influent
     Odors from sludge lagoons
Page

 121

 122
 123
 124
 125
 126
 127
                                48

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                                              »sx»VjA l^Ci .
            I.  PRETREATMENT - Pumping Plants
                SURGING OF PLANT INFLUEN
                    Intermittent flooding of.'weirs and structures.
Monitoring,
Analysis
and/or
.If a main sewage lift station pumps
   ck for frequent starting and stopping of pumps or more
than one pump operating at one time (out of phase) during
a pumping cycle.   -fg|» L/tAttLJ (& (fn^&fb M"ff/j/^^
                        ,-^M~-  ||j~—    ^    |   n»t lAAf
If influent flows to the plant by gravity through a main
trunk, check depth of flow in connecting sewers if
channel iSK uniform or monitor flow with a portable flow


If surging occurs during rainfall, record relation of
surging to duration of rainfall; and record or obtain
rainfall intensity if possible.
                    Surging  from  gravity influent  line  indicates  a  major
                    'pump/station  discharge  into  a  connect/ng  sewer.   Review
                    •water depth and/or/portable  flow meter  data to  determine
                    so/rce of  flow.   '
                    Intermittent  starting and stopping  or recycling of main
                    influent pump station or stations indicates improper wet
                    well sensor adjustment fy^ tha_t±he  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
                           rainfall indicates illegal-connections to system
                          s 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
  nitoring.
Analysis
and/or
Inspection
Corrective
Measures
1.  Intermittent flooding of weirs and structures.
2.  Pl_ant 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.
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 obtai
    rainfall intensity if possible.
    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 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.
    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.
    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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Problem
Indicators
            I.   PRETREATMENT - Pumping Plants  and  Influent Sewers

                              /I       ,\ K      "           ^
                ACCUMULATION OF SOLIDS OR SCUM IN  WET WELL
  &>
r$r

Monitoring,
Analysis
and/or
Inspection
Corrective
Measures
                    Scum blanket in wet  well
                                 t
                                            ^Pffiffi
                                            iment   «/ A teWf     *
                     mproper operation ofl\level  sensingf/equipment
                1.   Sound wet well  with a  pole  to determine solids level.
2.  Measure/owet well draw .downd
                                                      pumping cycle.
                3.   Ascertain relation or  pump  suction piping to floor of
                    wet well.
                4.   Determine elevation of inlet  piping.
                5.   Look for dead spots in corners  and structural cracks
                                                                  '  ^J&L
                 i   where sludge can^ccumulate,
                *   fad ^^a^/Lob^^
                i.
    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.
                2.   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.
                4.
                    If this is a persistent  problem  install air diffusers in
                    wet well with comp-ressors--wixed_^jo_Qpe^aj;.e-^in—t-andeiifwi't-h-
                    the—pumps..  Diffused air will  assist in placing the
                    solids in suspension ^and c/urtail thf development of a
                    scum blanket. /fD A
                                                                £)
                                                                                   \
                                                                                 ^  *
                                     51

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            I.  PRETREATMENT - Pumping Plants and  Influent  Sewers
Problem
Indicators
ODOR SOURCE IN WET WELL
i
2.
3.
Monitoring,  1
Analysis
and/or
Inspection

             3.
             4.


             5.
             6.
             7.

Corrective   1.
Measures
             3.

             4.
Odors of hydrogen sulfide origin

Corrosion of iron work and concrete

Black color observed in liquid or solids
                 I
Hang hydrogen sulfide (lead acetate) indifl
tiles in wet well.  (}W»-£- \X) V-
                                   Mf-we-tv wgfi  ah(i  analyze  for  total
                 Check for floating solids  in wet well.               /
                 Run dye test on influent sewer or  sewers  to  determine
                 velocity of waste flow and travel  time  to wet  well.
    Check temperature of wastewater  in wet well.

    Check pump invert position and condition.

    Check passage time in the interceptors at  flow  velocities.

    Low velocities  (less than 2 ft/sec)  are  an indication
    that solids are being deposited  in influent  sewer  and
    sulfides are being formed and released in  the wet  well.
                     increased in the sewer  or influent  must
    be continuouslyCreated upstream with chlorine  or  copperous
    to pi?olT±bi-fe~fefee**aevelopment of hydrogen  sulfide gas.

    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.

    Install air diffusers in wet well to keep  wastewater fresh.
    Install blower and gas scrubber  for  the  oxidation  of the
    gases and exhausting to the atmosphere.
    Dose wet well with£hyperchloride)on'  a periodic  basis to
    suppress the formatiotf"•crC-irygrogen sulfide.
                                     52

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                 I.  PRETREATMENT  -  Screening  and  Shredding
Problem
Indicators
Monitoring,
Analysis
and/or
Inspection
ACCUMULATION OF
               DEBRIS FOR DISPOSAL
    Large amount' of rags and debris*accumulated-.on  plant
    site gives off obnoxious odors and attracts \flies  and
    other insects.
                                                    .
     stimate volume '(cubic feet) of rags and debris removed
    eacB day-in PE9.pprjtJ.oii to flow.
ine
                                    v_     ^
                   exposed material Ts allowed to accumulate
                    Check disposal method  used.
Corrective      1.  Arrange  for  local  refuse  or  garbage  company to pick up
Measures            rags 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
                         tion.
    If none of the abokve
    debris can be grou
    equipment and retu
    should only
    shrejdded
              and i
                                           thods pro
                                         up by instal
                                         d"'to the pla
                                           a last re
                                         ay cause p:
                              feasible, rags and
                                the proper
                              flow.  This method
                               since ground or
                                 in pumping
                                     53

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                 I.  PRETREATMENT - Screening and Shredding
Problem
Indicators
Monitoring,
Analysis
and/or
Inspection
                EXCESSIVE GRIT IN BAR SCREEN CHAMBERS
Surging * in chamber-due
— l-r-TrSurging
     <2tAj8j
                                              incr
                                                       i-h waterVJLevel.
                2.  I/ow removal off grit by degritting equipment
                          -i y
                                     oJ—
                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
Measures
                1.




                2.


                3.
      If velocity in chamber is less than 2 ft/sec,  flush
      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.

      Remove irregularities or reslope chamber bottom; if
      possible, to increase velocity.
                                     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  concretx
Monitoring,
Analysis
and/or
Inspection   3.
1.
2.
             4.
Corrective
Measures
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.
                             and/3inaly/6fe foi\to,ckl
arid /dijfsSlteedy siW tide.
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                    I.  PRETREATMENT - Screening and Shredding
Problem
Indicators
Monitoring,
Analysis
and/or
Inspection
SHREDDED SCREENINGS, CLOGGING PUMPS

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

1.  Install pressure gages on discharge side of pump and
    check pressure daily.
2.  If pump discharge line visible, check flow daily.
3.  Check power input,  bearing heat pressures on inlet
    and discharge sides.
4.  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
                 bv 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
Indicators
Analysis
and/or
Inspection
Corrective
Measures
GRIT REMOVED HAS HIGH ORGANIC CONTENT
             1.

             2.

             3.

Monitoring,   1.

             2.
             3.

             4.
             3.

             4.
    Grey color

    Odors from

    Greasy fe
                             with^excessive components
                                                         I
    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
   iSterTTrTZtftionJof biological treatment.
                                                              esses
                3.  Digester upsets
               .4.  Change in influent odbi
                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.
                    Bypass all biological treatment processes  to parallel
                    units as soon as contaminant has been detected.

                    Isolate and dispose of all contaminate sludges.
                    If digesters show increases in volatile acids because of
                    contaminated sludges, see Section VII(b) for corrective
                    measures.
                    If activated sludge process has become contaminated,
                    dispose of floe and restart process.
                    Institute program of source control (industrial waste
                    ordinances).
                                     58

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            II.  PRIMARY TREATMENT - Primary Sedimentation Tanks
Problem
Indicators
Monitoring,
Analysis
and/or
Inspection
FLOATING. GASEOUS. OR/SEPTIG SJLUDGE
               V  . Mr. t
Corrective
i.
2.
     loating material! in ta
deadspots ortin sgum troughs

  igin
                    Dewater tanks and check sludge collector mechanism
                    (flights, chains and scrappers) for wear and tear.
    If total solids of raw sl&dge analyzed a
    cycle is over 2%, increase duration of pumping cycle,
    preferably with a timer.

    If sludge collector mechanism shows signs of wear during
    'inspection, repair or replace.

    Certain chemicals \ sutin\ as alum, used in\chemical
    treatment, .cause floatine sluage afVthis chemical is
    recirculated tW the, primajjy sedimentation rcanks.  Change
    operating/procedures or chemicaMis usedyl

    Long detention in sludge hoppers favors production
    of a sludge that readily slips.
                                     59

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            II.  PRIMARY TREATMENT - Primary. 'S«Mn.mentation Tanks
Problem
Indicators
LOW SETTLEABLE SOLIDS JlEMfcVAL EFFICIENCY!

                       ^
                        A
                              iAtj-A™ ^-rj^ £R
                2.  Percent settleable solids removal below  95%
Monitoring,
Analysis
and/or
Inspection
Corrective
Measures
                6.
1.




2.


3.
    Run settleable solids test (Imhoff Cone) during times of
    day where there are appreciable changes in plant flow.

    Check raw sludge removal pumping cycles and duration of
    pumping period.
                    Dismantle and/or inspect raw sludge pumps an
                    collection mechanism for wear and tear.
    Check tank inlets with relation to the tank ^outleYs.  If
    baffles have been installed on the inlets, dewater the
    tanks and check their condition.

    Calculate theoretical detention time, weir overflow
    rates, and surface loading rates and compare all data
    with design criteria.   h   v  .  -   ft * lu/j
    Try a dye test to estim^reWlow^trfrougntime.  Check
    for density stratification due to significant  tempera-f
    ture or density difference top sto bottom
If efficiency*of removal drops during peak or increased
plant flows, the hydraulic capacity of tanks has probably
been exceeded.  Refer problem to operating agency
engineering staff.
Repair all worn raw sludge pumps, parts and sludge
collector mechanism.

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.  Tleplace or repair baffles.
                                      60

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            II.  PRIMARY TREATMENT - Primary Sedimentation Tanks-
Problem
ERRATIC OPERATION OF SLUDGE COLLECTION MECHANISM
Indicators
Monitoring,
Analysis
and/or
Inspection
Corrective
Measures
1.

2.
    Frequent replacement of broken sheer pins on chain
    driven collector mechanisms.
                    Frequent torque switch activated alarms on concentric
                    driven clarifier equipment.

                    Visible slippage or "stuttering"
                    collection mechanisms.
                                     of clarifier sludge
    Check all drives for gear wear.

    Dewater tank and check chains and sprockets for wear
    see that chains have not come off sprockets.  &JC4£>

    Check to see that rags and debris have not entwined
    themselves around sludge collector mechanism.

    Check dewatered tanks for excessive bottom deposits of
    sand, rocks and other inorganic material.

    Sound bottom for excessive^ accumulation o£ sludge.  .        .^ _ ,
                                                      V> /lAs&Ot
    Repair all worn sludge collector equipment and drives.
                    If rags are a problem, make provisions for removal of
                    all rags and debris as part of the pretreatment process.

                    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.

                    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
Indicators
LOW SCUM (GREASE) REMOVAL
Monitoring,
Analysis
and/or
1.

2.


1.
                3.


                4.




                5.
Visible grease particles being discharge/
effluent   *
                      serve 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.
                                            ickup wiper blades.
                    If possible, lower return wooden flight to beVLow wateh
                    surface so grease particles do not adhere to them.
                    Install
                    surface
                    surface
                    |rays to direct grease particles on tank
                    !m troughs.   Water spray should not break
                  n on water surface.
    If scum removal is done manually and intermittently,
    continuous removal equipment should be installed.

    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.

    Efficiency of scum removal in plants receiving a high
    grease loading can be increased by the addition of
    flotation or evacuator equipment.

    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.

    Pump scum pits down on a regular basis so as not to
    cause scum overflows back into the clarifier.

    Clean and replace all worn wiper blades.
                                                                              f/
                                     62

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            II.  PRIMARY TREATMENT  -  Primary Sedimentation Tanks
Problem         TANK CONTENTS TURN SEPTIC

Indicators      1.  Tank contents are  a  dark  color
                r
                2.  Hydrogen sulfide odors  emitted  from tanks
Monitoring,
Analysis
and/or
Inspect
             /      \
RuA to±al/antf Idis^bJved^ulfi
taAk/Kj/fuent
                                                     teib
                     Run  DO test.
                     Check  quantity and total solids of all inflows into
                     tank from  other plant  processes such as digesters
                     supernatant,  thickener overflows,  centrifuge con-
                     centrates,  etc.
                     f tank influent  contains  high dissolved and totalj
                    sulfides,  influent  is  septi<
                    oorroot-problom.. a4~&g>u-pee..
                    If tank  influent  pH  is  below 6 or above 8,  toxic waste
                    is being discharged  yit^O|Dlant a^nd mpfctlbe  oprMkcted a
                    the source.  M tyUtAwijtf /$A^4[U4AA  H?P
                    If discharges  rrdmSother  nJWfnt processes contain
                    excessive total soli&sa«ncl  exceed 5% of the daily tank
                  .1)inflow,  the  sedimentp^ba».^ank is being overloaded.   If
                    \possible, reduce  n^re of  precede flows  to sedimentation
                    tanks or pretre-er  flows by  aerating <•>]-  fhinri patjng them
                    If possible divert  or  find  other means  of disposal for
                    supernatant or  centrates.
                                                               tX?
                                      63

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             III.  SECONDARY TREATMENT - Activ
               3.  Filamentous growths in mixed  liquor
Monitoring,
Analysis
and/or
Inspection
1.

2.


3.



4.
 Check mixed  liquor  for low pH and low dissolved

 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.
•"lir rli' fnr TOPI ind-jff
Corrective
Measures
    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.
                                              TeTOrTT activated  sludge.
                          sludge age and air rate -jrg^stojj ^nili'lf icatjxnr;
                   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
                      operation if possible or reduce the return sludge
                     te by thickening the return sludge concentration
                   by coagulation.

                   Control filamentous growth by increasing sludge age
                   or supplementing nutrient deficiencies.
                                                             inimum
                                    64

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               III.  SECONDARY TREATMENT - Activated Sludge/Process
               ERRATIC SLUDGE VOLUME INDEXES
Indicators
               1.  Pin floe visible in final clj^ifiers overflow

               2.  Poor settling characterisj^cs of mixed  liquor
                                                  lids in each aerat
Monitoring,
Analysis
and/or
                                     tleability test in each aeration
Inspection
                                     the point floe is a recurrent
                                    result of toxicants.
                   Determine^whe
                   situation or
                   Regulatsr wasting to decrease suspended solids
                   mixed Xiquor .
                   Chlflfrinate return activated sludge.
                     crease-solids loading to aeration tanks.
                   Make appropriate adjustments to obtain a less
                   oxidized sludge.
                                    65

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                    III.   SECONDARY TREATMENT - Activated Sludge Process
        Problem
        Indicators
DIFFICULTY IN MAINTAINING BALANCED MIXED LIQUOR
DISSOLVED OXYGEN AN AERATION^TANK
        Monitoring,
        Analysis
        and/or
        Inspection
        Corrective
        Measures
N?
\
    Intermittent sludge bulking
2.  Loss of sludge blanket in secondary clarifier

3.  Dark color in the aerator contents
1.  Check D.O. concentration in different areas of aeration
    tanks during changes in daily flow.

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

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

4.  Monitor rate of flow to aeration tanks.
5.  Check daily flow variation in loading for excessive
    peak demand periods.
1.  Lower D.O. concentrations occurring during changes in
    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 systt
   Aportion oiVthe
   V ,i-*i
    If possible, bypass a
 he primary sed
ns to normal

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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
Measures
1.


2.


3.

4.
If practical, increase mixed liquor suspended solids  by
decreasing wasting rate.

Install or operate reclaimed water sprays  in aeration
tanks.
                    Utilize defearning agent.
                                           i**Fr      "
                    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

                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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                FACILITIES  INADEQUATE FOR DISPOSAL OF WASTE ACTIVATE
               \  (HIGH  SUSPENDED SOLIDS IN THE CLARIFIER OVERFLO^)
                  SECONDARY TREATMENT -  Activated Sludge Process
                1.  High  suspended  solids  in mixeiL_ii£LuJor
                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
Measures"
                1.
                       sludge lS~n«JL_ae.t±*iTi"g '±~n
                        flnw-nf mini — mirier  rn rTii rlrrnrr~nr
                    thj^skenorj  inrrra
                    dose thickener  inflow with coagulants.
                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 *f jmrr>n-nt£% 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
Corrective
Measures
1.  Run S-.V.I-. "T.n 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.
1.  Adjust valves and
    tanks when operating u

2.  Equalize air flow
    air discharge line
es to equalize flow to all
conventional mode.
                                             tanks by throttling valves on
                                     71

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                   III.  SECONDARY TREATMENT - Trickling Filters
   Problem
   Indicators
   Monitoring,
   Analysis
   and/or
   Inspection
   Corrective
   Measurete
    H  -• ''
'•''<£ ^

ICE BUILDUP ON MEDIA
1.  Visible ice formation on filter media
1.  Check air temperature.           Jr
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.
1.

2.


3.



5.
By regulating amount of recirculation rate, adjust. flow\ -,
to filter to proMbit the formation of ice. AX\£/\ 1 \*  \
            ]'//••'/                           '       "    n
Adjust flows from orifices and splash plates to reduce
spray effects.

Cover filter to reduce heat loss.es or install a windbreak
to reduce chill factor.
Manually break up and remove major ice formations. .

If possible, add hot water or steam to filter influent.
                                         72

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                 III.   SECONDARY TREATMENT - Trickling Filters
Problem
Indicators
Monitoring,
Analysis
and/or
Inspection
FILTER ODORS

       /
        o
1.  Orlnrfl nf tiydrnfrn  nrtilfirir nrif-in present
        il/
      ack slime visible on surface of
1.  Ch^Bk^dTssolved  and total sulfide of
2.  Check filter dj-aiois  for stoppages or growths.
               &tA/y %{*
3.  Check rate (of  recireulation to filter..^
                        U           QM^
4.  Check ,-for  Miter, overflow or jSplashjLr
              0
Corrective   «,"   1.   If flow to filter is septic,  correct  in upstream system
Measures   \
          . ""
for
l™--~
    by aerationor  controlled prechlorination
                                                          ation. |
                                                         ...,_. »«^
            Vr.""2.   Clear under drain system of  all  stoppages.

         A°   I*   3.   Force air into filter drain  system to increase ventilation*
      '\ V  tk^        through filter media.                                  rJv"'
      \  . f\                                                               ff- ' \
                 4.   Increase recirculation rate to  filter to increase|D.fO.
                     and to, slpuglxvc&f f'.feurfaoe "Slime.   jSM | | 1 **" |,AA { ^ ( t •(  i
                 5.   Keep areas around filters clean  of  slimes- and growths.

                 6.   Cover filter wi ^h J1Hejrt'i»rna't:p'>"i.fll^air'f1^fixhaust air into


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                III.  SECONDARY TREATMENT - Trickling  Filters
Problem
FLY NUISANCE IN VICINITY OF FILTER
Indicators      1.  Tiny gnat sized  flies becoming  a  nuisance in plant  area
                    and in neighboring  area
Monitoring,
Analysis
and/or
Inspection
Corrective
Measures
1.  Inspect grounds for tall grass, weeds and other
    sanctuaries for filter flies.     »
1.   Increase rate of recircuJLation .to .filter^ to waslj. fly
    larvae out of filter.
                                                    \
                                                    \
                                                 aslj. f
                                                   V*
                2.  If possible,  flood  filter  for approximately 24 hrs.  to
                    prevent  completion  of  life cycle  of flies.

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

               V/'2-Maintain grounds so as not to provide sanctuaries for
               f * flies.
                                                         I
                                      74

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                III.  SECONDARY TREATMENT - Trickling Filters
Problem
Indicators
Monitoring,
Analysis
and/or
Inspection
CLOGGING AND PONDING OF FILTER MEDIA
1.
2.


1.
2.
3.

4.
5.
    Ponding on filter surface

    Intermittent flooding of filter


    Check size of filter media for uniformity

    Check for cementing or breaking up of media.
    Check for fi
    or snails in
slime growths, trash, insect larvae,
r media voids.
                    Check organic loading on filter.
                    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 s/pray fron^a stationary distributor.
                                      y to lessen or remove any
                    Flood filter media
                             ccumuiations.
                        growth
                    poasttTTet
                                     75

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                III.  SECONDARY TREATMENT1- Trickling  Filters
Problem
CLOGGING OF DISTRIBUTOR NOZZLES CAUSES
                     nfj TTITT F.TTTTOT]
Indicators
Monitoring,
Analysis
and/or
Inspectien
Corrective
1.

2.
1.

2.
Uneven sprays from distributor nozzles
Ponding on certain areas of the filter media with
concurrent drying of other areas
 ttempt to identify types OT solieqf clogging nozzles.
Check for visible grease particles in waste being
pumped to filtej
     .emove and clean all nozzles and thoroughly flush
    distributor piping.

    Improve primary clarifier skimming to prevent grease
    carryover to filter.
                    Increase detention
                    settleable and suspend
                 \
                               primary tanks to prevent
                              olids 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
Corrective
Measures
1.   Check water depths in selected areas of the pond
    Deepen all pond areas shallower than three feet.

    Remove all weed and tule growths as soon as they are
    visible.
                    every 10 days.
                                          varY liquid level in the pond
                                     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.
                                           Sir
                5.  If pond is septic, divert flow from aerobic pond to
                    or pump high D.O. make up water to it.
                6.  Add sodium nitrate to pond.
                                    78

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                 III.  SECONDARY TREATMENT  -  Oxidation Ponds
Problem
Indicators
LOW POND DISSOLVED OXYGEN
1.  Low algae growth in pond
2-,
                    Traoo hydge§eB-&u3^£d.de..odor.
Monitoring,
Analysis
and/or
Inspection
                3.  Grey  color  of  pond
    Check all areas in pond for 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.

    Run total and dissolved sulfides  in pond  influent.
                5.   Check  pond  loading rate (Ib BOD/acre).

                                            t~i c '"weedHT""*'
                                        aq
Corrective
1.  Increase detention  time  in  ponds  to at  least 5ive days
 ~~~~ by placing ponds in parallel.
                 2.   In the  absence of adequate D.O.  in the pond, aerate pond
                     contents  or pond influent.
                                                              I
                                                                                 '
                4.  Physically remove  floating weeds/£0 increase light
                    penetration.
                                      79

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               III.  SECONDARY TREATMENT  -  Final Sedimentation
Problem
Indicators
Monitoring,^
Analysis
and/or
Inspection
SLUDGE OR PIN FLOC FLOWING OVER WEIRS
1.  Particulate material rising to  surface  in clarifier

2.  Effluent clarity poor
Corrective
Measures
                                   discharged from clarifier
                    Attempt  to  determine  height of sludge blanket in
                    clarifier with  depth  sampler TIT I rnl    uirnfTlm pi>\p

                    Ktm/s>u^peni*ed sp4J:5Js>el<^^

                       eck  all sludge uptake piping to see that they are
                     flowing  freely nntl
                        from.Di
6.  Check pump rates  and  schedules  of sludge withdrawal
    pumps.
         'N             	        x-\    ^^
                                                 -1-udge
                                ly at the periphery of th
    tank.
8.  Determine if the  weir overflow  rate is equal for
    the entire weir.


              P
1.  Increase pumping  rate for  greater removal of sludge from
    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
    Determine types and amounts of chemicals used.
                   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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DUB
                  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      1.   Use large flow distribution orifices  at  the  outside  face
 Measures            of the tower thus concentrating  a  curtain  of warm water
                     where the cold air first  enters  the tower.

                 2.   Reverse draft fan to blow warm inside air  outward to
                     melt the ice.

                 3.   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 flashing of aciCumulated  /Jlids  from ^rbon  columns
                   is followed by ajy abrupt increase in  th^ rate of
                   absorption     '          /           /
               2.  Pressure rises in downflow columns
               3.  Decrease in flow rate.
Monitoring,
Analysis
and/or
Inspection
Corrective
Measures
    Run suspended solids and total organic carbon of
    column influent and effluent.
3


1.


2.

3.
                   Check columi  operating routine and backwash  records.
    Bypass column  ^ifluent with large amounts of  suspended
    matter.
                   Flush columns frequently.

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

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Monitoring,
Analysis
and/or
Inspection
                       V.  DISINFECTION - Chlorination
                INSUFFICIENT CHLORINE GAS PRESSURE AT THE CHLORINATOR
                 ITH ALL CYLINDERS CONNECTED TO GAS PHASE
                    Chlorine pressure gage at chlorinator is reading too low.
                    Chlorine supply lines from cylinders are either very
                    cold or are icing.
                          ne cylinders or cylinder show a frost line.
    o about one-tenth the
Reduce feed rate on chlorinator
rotameter capacity.
                          '/*
hlorine gas pressure risesmJ^
   that the rate of feed ft/^
                                                ded
If after a short period the
appreciably it can be cone
through the chlorinator \f greater than the evaporation
rate of the chlorine cyynders or cylinder at  the
prevailing ambient temperature.
Corrective      1.  Connect enough cylinders to the supply system so that
Measures            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.

                2.  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.

                3.  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
    Reduce feed rate on chlorinator to about one-tenth the
    rotameter capacity.

    If icing condition or cooling effect does not disappear,
    mark the point wh\ere cooling begins and secure the chlorine
    supply system at vhe cylinders, but let the chlorinator
    continue to operate\
Corrective
Measures
    When chlorine gas pressure at chlorinator reaches zero
    and 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.)

    Disassemble chlorine header system at point where cooling
    began.  A stoppage or a flow restriction will be found
    at or near this point.

    After the stoppage has  been found it  can be cleaned with
    a solvent such as tri-chlorethylene.

    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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\Indicators.
                        V.  DISINFECTION - Chlorination
                 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.
Monitoring,
Analysis
and/or
Inspection
 Corrective-
 Measures
                    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.
                    The entire chlorine supply line back to the cylinder  is
                    also iced over, but cylinders are at about ambient
                    temperature.
                     Inspect the chlorine cylinder area to see  if  they  are
                     connected properly.  (This problem is specific  to.  ton
                     containers.)                           tv
                    Shut off main outlet valve on all cylindersAand evacuate
                    chlorine in header system until gage pressure at
                    chlorinator reads zero.
                     Disconnect the cylinder that had     ,.  ,, _  , ,  ,    	
                     connection to the outlet valve and^rotate it  180  Jand
                     ^reconnect to ,toji_QiLLlet valve and witn j'otner  cylinders
                     closed7place this one in operation.
                     Tag cylinder so that packager can identify  it as
                     defective with possible broken dip tube  but allow
                     cylinder to remain in1 use until empty..

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                       V.  DISINFECTION - Chlorination
Problem
CHLORINATOR WILL NOT FEED ANY CHLORINE EVEN THOUGH
ALL SYSTEMS APPEAR NORMAL.
Indicators
    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.
Monitoring,
Analysis
and/or
Inspection
    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
Measures
    Shut off chlorine supply at the cylinders and try to let
    the chlorinator drain off all the chlorine gas pressure
    in the chlorine supply line.

    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.

    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.

    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.

    Inspect cylinder area to see if anything can be done to
    make the area cooler.

    Do not connect a new cylinder if it has been allowed to
    sit in the sun.

    Install an external chlorine pressure reducing valve
    adjacent to the last chlorine cylinder connected to the
    supply system.
    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
    The symptom described indicates that the main diaphragm
    of the CPRV has been ruptured.
    Remove the external CPRV after evacuating header system
    and replace with a jumper tube for temporary operation
    while valve is being repaired.
    Disassemble valve and replace diaphragm.
    Inspect the ruptured diaphragm to see if failure is from
    corrosion, improper assembly or just fatigue from length
    of service.
    Consult manufacturer for expert opinion.
    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      1.  Check for stoppage in the external CPRV cartridge if
Measuressuperheat cannot be measured.

                2.  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
    After evaporator has been in operation sufficiently long
    enough 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
    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
1.  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.

2.  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,
Analysis
and/or
Inspection
1.  Scattering ammonia indicator solution onto the wastewater
    stream over the area of the diffuser produces white fumes
    at the surface.
2.  Check 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 shows 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,     1.  Ascertain that if the chlorination equipment is being
Analysisused for disinfection that it is equipped to proportion
and/or              the chlorine feed rate in accordance with the flow of
Inspection          the wastewater.
                2.  If it is flow proportional, check to see if the meter
                    capacity on the chlorinator matches the pl'ant 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 types
    of electric and pneumat'ic signals commonly used for
    chlorinator control.

    If neede'd'', 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
    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
    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,
Measures            satisfactory 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.
Routine analysis of effluent or receiving waters shows
MPN coliform organism to be in excess of that required
by regulatory authorities.
Monitoring,  1.  Check capacity of chlorination equipment as follows:  For
Analysis         primary effluent chlorinator capacity should be from 175
and/or           to 200 Ib per MG.  For secondary effluent 100 to 125 Ib
Inspection       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.
             2.  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.
             3.  Continuously record the residual in the effluent with an
                 amperometric type chlorine residual analyzer.
                                                      N
             4.  Check for short circuiting in contact chamber.

Corrective   1.  Chlorination equipment should be brought up to optimum capac-
Measures         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      1.  Toxicity level is too high as determined by present
                    bio-assay procedures.
Monitoring,     1.  Chlorine residual as determined by iodometric method
Analysis            using back titration method is deemed toxic to fish and
and/or              other aquatic life in the receiving waters.
Inspection
Corrective      1.  Install a dechlorination facility to operate in
Measures            conjunction with the Chlorination system.
                                     108

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Problem
Indicators
Monitoring,
Analysis
and/or
Inspection
                                VI.  METERING
PLANT. METER UNRELIABLE
     A. .
    Drop or sharp increase in totalized .dry weather
    If meter operates on a float, check float well
    obstructions.

    If meter operates on bubbler, check bubbler tube for
    damage.  Also check air pressure gage to see that meter
    is getting proper air flow.

    Bypass measuring weir or f
    to see if meter Zespos..
                    Check height lof flow over weir or in/ flume at dlfd
                    time intervals and, using the weir or flume characteristics
                    formulas  calculate flow and compare with flow meter data.

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

                    Ascertain the fact that none of the plant's process
                    return flows (centrate, supernant, waste activated
                    sludge, etc.) are discharged upstream from the meter.

                    Install a portable flow meter in the weir or flume and
                    compare results with
                    If metered flow discltarges/iinto a wet well or other
                    chamber which has.,* known volume and outflow can be shut
                    off, record time' of measured rise in chamber and
                    calculate infl<6w rate.  Compare calculated data with
                                     109

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                    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 *Aow meter cores for grease bui.M-uB.Q
                     estrictions. .                   .


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
Monitoring,
Analysis
and/or
Inspection
1.  Odors of hydrogen sulfide origin

2.  Floating or gaseous sludge in thickener

3.  Corrosion of thickener concrete structure and metal work
1.


2.


3.

4.
    Run/Total and
      ffluent.
^solved
test of thickener
    Check pumping rate and frequency of pumping raw sludge
    from thickener.

    Run total solids test on raw sludge pumped.
    Dewater thickener and check operation of a scrapper
    and/or stirrer arms and sludge removal equipment.
                5.  Determine sludge blanket depth.
Corrective
Measures
1.  Adjust pumping rate to remove solids at a frequent rate
    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
 Indicators
Monitoring,
Analysis
and/or
Inspection
  THICKENER CONTENTS DO NOT SETTLE
  1.   Floating sludge on thic

  2.   Floe in thickener effluent

\^/Xlny3^reased^\oadi*lgs~^n P/"Vnar y^sedinrenVarciW^fanics and
      secoh43«ry treatment p**°cess*/  \s
  4..   Excessive sludge solids in the overflow

  5.   Poor concentration of underflow.
     Run tota1J'ssolids  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
     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

-------
                    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

-------
            VII.  SOLIDS HANDLING - Sludge Digestion (Anaerob
Problem
Indicators
SCUM BLANKET IN TANK
Monitoring ,
Analysis
and/or
Inspection

. 1.
2.
3.
4.
1.  Decrease in dige'ster gas production
2.  Crust visible through sight glasses in digester roof g *
3.  Unable to supernate from upper level of digester
                    Core blanket through digester thief holes to
                    thickness.
                    Check digester temperature.
                    Check daily digester gas production.
                    Determine gallons of scum pumped to digester daily.
Corrective
Measures
    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 holies and pipe compressed digester
    gas /to them.
                                     114

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         VII.
   LIDS HANDLING,- Sludge Digestion  (Anaerobic)
                 DIGESTERGAS PRODUCTION
Indicators
Monitoring,
Analysis
and/or
Inspection
Corrective
Measures
              2.
              3.
              4.
2.
3.
4.

5.
6.

7.
8.
    Gas produced hafe sen^fic
    Gas producedyrfoes ifot ignite^
    Increase in^ligearcer volatile acids
    Increase ±y vol^ile acid/alkalinity
Determing digester volatile acid, alkalinity, and pH
of digested sludge together with trend of volatile
acid/alkalinity ratio.
Check gas meter and piping for restrictions.
Monitor volume of raw sludge pumped to digester daily.
Determine total solids, volatile solids, and pH of raw
sludge pumped to digester.
Check digester temperature.
Sound digester to determine depth of scum blanket and
grit residue on bottom.
Calculate volatile matter reduction in digester.
Check for toxic material i
                                                   digeste
    If volatile acjra to alkalinity
    0.2 and pH billow 6.5 add/lime
    volatile a/ld/alkalin/i r
    Do not fe^a digestejr raw
    than 7.
    If volatil
    decrease,
    Do not
    solids
                              disconti
                                        greater than
                                             decrease
                                            pH.
                                          ranges  (less

                                               50%
                                               pH rises
                          eefci djAest'ej5xrawvSi3jJ4ge— with  average volatile
                         l3S'
                 x
              an-^75%.
If possible transfer digested sludge with a volatile
acid/alkalinity ratio of 0.2 from another digester  to
affected digester.
If scum blanket and/or grit deposits comprise more  than
50% of the effective volume of the digester, clean  the  (
tank.                                *  iJf^ijjJti AAMW^A
Keep digester temperature at 98 F.  (vflM/TUA**  r*'v'rw  I
   r   o         r                                     •
Clean all restrictions in gas lines and/or meters.     v_
If toxic material has killed digester,  clean digester
and determine source of toxicity to prevent recurrence.


-------
            VII.  SOLIDS HANDLING - Sludge Digestion (Anaerobic)
                INCREASE IN VOLATILE ACID/ALKALINITY RATIO IN DIGESTER
Indicators      1.  Drop i/i digestenrgas production
                2.  Hydr/gen sulfd^fle odoijr from digegrter superna
Monitoring,
Analysis
and/or
Inspection
Corrective
Measures
1.

2.
3.
4.

1.
2.

3.
4.
5.

6.
7.
Determine volatile acid, alkalinity and pH
sludge at least twice daily.
Check digester temperature.
Check pH of raw sludge pumped^to cfigester.
Check mixing in digester.
If digester pH is below 6.5, add lime to digester
                    If volatile acid/alkalinity ratio is greater than 0.4
                    decrease or discontinue feeding digester and add lime.
                    Do not feed digester raw sludges with pHs lower than 6.8.
                    Do not let digester temperatures drop below 90°F.
                    If possible, transfer sludge with low volatile acid/
                    alkalinity ratio content from another digester to
                    affected digester.
                    Keep contents of digester well mixed.
                    Decrease sludge withdrawal rates from digester.
                                     116

-------
            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

-------
            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



3
4
5
                    Determine total solids of digested sludge and/or raw
                    sludge being pumped to digester.
                    Monitor solids loading to digester daily.
                    Monitor solids withdrawal from digester.
                    Check total solids in digester supernatant.
                    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
Measures
                2.
                3.

                4.
                5.
    If total or volatile solids daily loading of digester
    exceeds design loading, reduce the amount of sludge
    pumped to the digester daily.
    Keep digester temperature above 95°F.
    Raw sludge pumped to digester should contain more than
    50% volatile solids.
    Recirculate and mix digester.
    Prolong periods of withdrawing digested sludge until
    volatile reduction is above 50%.
    Lower volatile acid/alkalinity ratio and raise pH above
    6.5 by adding lime to digester.
    If supernatant contains high solids content, let
    digester settle.
                                     118

-------
            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

-------
                    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
1.  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

-------
                    VII.  SOLIDS HANDLING - Incineration
Problem
ABNORMALLY HIGH TEMPERATURE IN FURNACE
Indicators
    Temperature indicator exceeds limit of maximum operating
    temperature.

    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

-------
                    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

-------
                    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.
and/or
Inspection
                2.  Check to determine if sludge is being fed to incinerator.
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 stator if 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

-------
                  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

-------

-------
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

-------
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
   (MGD)      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

-------
      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
     Hawai i
                        LOCATION OF TEMPERATURE ZONES
                        IN THE UNITED STATES
                                     'A-3

-------
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

-------
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

-------
UNIT OPERATIONS
PRIMARY®
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Sand Filtration >
Carbon Adsorption >
9
Sludge Treatment A. Disposal












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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
. Microscreening
. Deep Bed Sand Filtration
(Rapid sand filtration)
. Phosphorous Removal
(Chemical treatment)
. Ammonia Stripping CD
. Electrodlolytii
EFFL
o
2
15-65
er* in
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70






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60-S5




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50-80





<5
n
«
5
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90-99



70-8$
2-4

<5
Suspended Solidl 1
<5-75






85-90
20- JO
60-80
80-100

74-94
17-29

100

60-80
< 7
30-80
3-5
60-85

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100
90
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60-100
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MUTUAL
SCCTIOff
flicJtoround
Ops Oita
Probleam
L-l to C-JJ
11-19
IV 43-63
D-7 to D-9
11-22
IV 64-71




D-5 to D-6
11-21
IV 72-76


D-9 to D-ll
11-31
IV 77-79
D 13-14
11-31
C-l to E-8
11-24
VI 82-il







^-V function of pH and temperature
®Not all operations are used 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

-------
B

-------
PERSONNEL

-------
                                   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

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               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  (MOD)

                       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
Hauled to
sanitary landfill
or incinerator
i	1
1 Chemical addition '
I ,      ...    I
i for precipitation  |
                        Influent  \   From combined system
                                    or sanitary system
                                  	By Pass
                                                    Prechiorination wet well
                                                    Weir for flow control
                          CUTTERS
                          SHREDDERS
                          COMMINUTOR
                         PP.EAEPAT1OM
                         *-* r.r • rr  o r%r\/
                         \^l\l_/-VJi-  (Ji v-*Lyv
                         CONTROL
                          FINE SCREENS
                         SEDIMENTATION
                                                   LAGOONS
                                                                           -fc
                                           sludge
     DIGESTER
                             CHLORINATION &
                             CONTACT CHAMBER
                                               1
                   Secondary system
Effluent
discharge
                                                       r*
                  VACUUM
                   FILTER,
                                                                             ^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.
                                                             / //]/ trough
                                                                 rack
          a)  Fixed Bar Rack                  b)  Mechanically Cleaned Rack
                          Fig.  C-2.  Fixed Bar Racks
                                     C-3

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      7046
     Figure O2a 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
              SECTION
                          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.
                                     07

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DDDB
7046
                                      3    4
                                     Tims, 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

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o
                 REPRESENTATIVE
                 LONGITUDINAL-FLOW SETTLING TANKS
                                        Rectangular, hand-cleaned
                                        tank with sludge hopper
                                        Tank a provided with track-
                                        mounted sludge scraper
                                        (Mieder tank)
                                         Rectangular,  hopper-
                                         bottomed tank with
                                         hydrostatic sludge
                                         removal
:-^^-—---ri   Square tank with cross flow
                           (d)
                                        and rotary sludge scraper
                                        (Dorr Co.)
   ,'v^  Rectangular tank with sludge
   ^i   scraper and scum collector
         (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 i equipped with
                                                                                                   sludge scraper
                                                                                             Tank
                                                                                                             -J
                                                                                                             O
                                 c^i7.\i   Tank e with cross collector
                                 lilpJ!    for sludge and scum
                                         (Link-Belt Co.)
                                                                ;_>  Circular tank with sludge
                                                                    collector to which scum
                                                                    collector can be added
                                                                    (Dorr Co. )
                                                       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
                         U
          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
                                                  Mixing Baffle
         Flow Control Weir                " Chlorine Diffuser

                           SECTION A-A
               Fig.  C-6.   Final  Chlorination  System
                                C-ll

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      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.
                                    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

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to
                               Wastewater
                                   I
                              Pre-Treatment
                                                                                            Secondary Clarifier
1 1 1 1 1 1 1 1 1
> — - c ' 1 1 »
Primary Sedimentation f f Biological Reactor
-7 — r 1 1
11111111 i i
x i i


/ i I

llil

Lf-^ 	 ©*-
^"^ 1 Slud
•- - 1 — Dinr
Trea
—— Ff fluent
ge
stion &
Irnent
— ^ Sludge
Wastewater
Effluent
To Final
Receiving Body

MM ^^ «M^ ^^m «^^
Chlorine
Contact
Chamber
1
1
Sludge
J


Final Sludge
Disposal



o
^
CD
                                                                                                      Chlorination
                                Fig. D-l.   Flow  Diagram  of a Secondary Treatment System

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     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.
               WASTEWATER
                        AIR
          AIR \
I -n
m —
^5
j> m
\\X\\\\\\\\\\\\\\\\\\\\\\
H2S
ORGANIC
ACIDS
ANAEROBIC
EFFECTIVE
FILM DEPTH
-* 	 h 	 *•
BOD
°2
co2
AEROBIC
WASTE
1 1

i 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-
            introduced at one end of the reactor a]
            sludge.  The length of the reactor
            width.  The diffusers are located i
            tank so that the diffused air bull
            rolling motion on an axis parallel £to th.e/*4hMh of the tank.
            This class of activated sludge process prtoviWes 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 nitTTrfica-
       tion tank where a mixture of supernatant and returned activated
              is aeratec/f24yhours and returned to the activated sludge
       unit?  Jfeiek),.fromVTrtyppiying 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/lW)
            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-
                                              CD '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
                   iii 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-O'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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      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 Culp
                                            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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      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, Gulp and Gulp
                                            Advanced Waste Treatment Seminar,
                                              Section IV.
                                     E-6

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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:

           a  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.
                                   F-3

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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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DOE
                           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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       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 Dall 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 (OKP) (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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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 ganitary 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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                                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
BY-PASS
CHLORINE
CONTACT
CHAMBER

CHLORINE
DEMAND
COMBINED
AVAILABLE
RESIDUAL
CHLORINE
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.

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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     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
VOLUME
INDEX
(SVI)
SUSPENDED
SOLIDS
(SS)

WASTED
SLUDQS
WET
WELL
A numerical expression of the settling characteristics
of activated sludge.  The ratio of the volume in
milliliters of sludge settled from a 1000 ml sample
in 30 minutes to the concentration of mixed liquor in
milligrams per liter multiplied by 1,000.

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

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

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

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