United Stales
Environmental Protection
Agency
Technology Transfer
Office of Research
and Development
Cincinnati OH 45268
EPA/625/6-91/027
February 1991
Handbook
Optimizing Water Treatment
Plant Performance Using the
Composite Correction Program
-------
EPA/625/6-91/027
February 1991
Handbook
Optimizing Water Treatment Plant
Performance Using the
Composite Correction Program
Office of Drinking Water
Office of Water
Cincinnati, OH 45268
Office of Technology Transfer and Regulatory Support
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
>/-.$ Printed on Ror.ycW P;wc
-------
NOTICE
This document has been reviewed in accordance with the U.S. Environmental Protection
Agency's peer and administrative review policies and approved for publication. Mention of
trade names or commercial products does not constitute endorsement or recommendation
for use.
-------
BIBLIOGRAPHIC INFORMATION
PB93-116267
Report Nos: none
Title: Handbook: Optimizing Water Treatment Plant Performance Using the Composite
Correction Program.
Date: Feb 91
Authors: R. C, Renner, B. A. Hegg, H. Schultz, J. H. Bender, and E. M. Bissonette.
Performing Organization: Process Applications, Inc., Fort Collins, CO.'"rEastern
Research Group, Inc., Arlington, MA.
Performing Organization Report Nos: EPA/625/6-91/027
Sponsoring Organization; '"'Environmental Protection Agency, Cincinnati, OH. Office
of Ground Water and Drinking Water.
Supplementary Notes: Prepared in cooperation with Eastern Research Group, Inc.,
Arlington, MA. Sponsored by Environmental Protection Agency, Cincinnati, OH. Office
of Ground Water and Drinking Water.
NTIS Field/Group Codes: 50B, 68D
Price: PC A10/MF A03
Availability: Available from the National Technical Information Service,
Springfield, VA. 22161
Number of Pages: 209p
Keywords : '^Handbooks , *Water treatment plants, ''Surface waters, *Fi 11 rat i on ,
Disinfection, Standards compliance, Water pollution standards, Requirements,
Performance evaluation, Implementation, Revisions, Water quality, '^Composite
Correction Program, Surface Water Treatment Rule.
Abstract: The handbook is an interim version of a source document for individuals
responsible for improving the performance of existing surface water treatment
plants using conventional and direct filtration unit processes to achieve
compliance with the Surface Water Treatment Rule (SWTR). The SWTR covers all public
water systems that use either surface sources as a raw water supply or ground-water
sources determined to be under the direct influence of surface water. The handbook
presents procedures for assessing a conventional or direct filtration plant's
capability of achieving the 0.5 NTU turbidity requirement. A method is also
presented for projecting if a plant will be able to meet the disinfection
requirements in the SWTR guidance manual.
-------
ACKNOWLEDGMENTS
This handbook was prepared for the United States Environmental Protection Agency (U.S. EPA) by
Process Applications, Inc. under subcontract to Eastern Research Group, Inc. Although many
individuals contributed to the preparation and review of this document, the assistance of the
individuals listed below is especially acknowledged.
Major Authors:
Robert C. Renner and Bob A. Hegg, Process Applications, Inc., Ft. Collins, CO
Jon H. Bender and Eric M. Bissonette, U.S. EPA Office of Drinking Water (ODW),
Technical Support Division (TSD), Cincinnati, OH
Project Managers:
Jon H. Bender, U.S. EPA ODW, TSD, Cincinnati, OH
James E. Smith, Jr., U.S. EPA Office of Technology Transfer and Regulatory Support
(OTTRS), Center for Environmental Research Information (CERI), Cincinnati, OH
Heidi Schultz, Eastern Research Group, Inc., Arlington, Massachusetts
Reviewers:
Robert Blanco, U.S. EPA ODW, Washington, DC
Peter Cook, U.S. EPA ODW, Washington, DC
Dan L. Fraser, Montana Dept. of Health and Environmental Sciences (DHES),
Helena, MT
Donna Jensen, Montana DHES, Helena, MT
Richard J. Lieberman, U.S. EPA ODW, TSD, Cincinnati, OH
Denis J. Lussier, U.S. EPA OTTRS, CERI, Cincinnati, OH
James Melstad, Montana DHES, Helena, MT
William Parrish, Maryland Dept. of the Environment, Baltimore, MD
James E. Smith, Jr., U.S. EPA OTTRS, CERI, Cincinnati, OH
James J. Westrick, U.S. EPA ODW, TSD, Cincinnati, OH
Victor R. Wilford, West Virginia Dept. of Health and Human Resources,
Charleston, WV
Editing and Production:
David Cheda, Karen Ellzey, Susan Richmond, and Denise Short, Eastern Research
Group, Inc., Arlington, Massachusetts
-------
Intentionally Blank Page
-------
CONTENTS
Chapter Page
List of Figures vii
List of Tables viii
1 INTRODUCTION 1
Purpose 1
Background 1
Development of the Composite Correction Program Approach 1
Montana Demonstration Project 2
EPA Demonstration Project 2
Scope 2
Using the Manual 2
References 3
2 COMPREHENSIVE PERFORMANCE EVALUATION 5
Objective 5
CPE Methodology 5
Evaluation of Major Unit Processes 5
Conducting Performance Assessment 10
identification and Prioritization of Performance-Limiting Factors 14
Assessment of Applicability of a CCP 19
CPE Report 19
Conducting a CPE 19
Personnel Capabilities 20
Initial Activities 22
Data Collection 22
CPE Report 27
Case Study 27
References 31
3 COMPOSITE CORRECTION PROGRAM 33
Objective 33
CCP Methodology 33
CPE Results 33
Setting Priorities for Process Control 33
Long-Term Involvement 34
Facilitator Tools 34
Correcting Performance-Limiting Factors 38
Conducting a CCP 44
v
-------
Initial Site Visit 44
Offsite Activities 45
Followup Site Visits 46
CCP Results 46
CCP Summary Report 46
Case Study 47
Personnel Capabilities Required for Conducting CCPS 48
References 49
4 FINDINGS FROM FIELD WORK 51
Introduction 51
Results of Comprehensive Performance Evaluations 52
General 52
Major Unit Process Capability 52
Overall Factors Limiting Performance 53
Plant-Specific Findings 54
Followup Results 63
State Impacts 63
Results of Composite Correction Program Implementation 63
Plant 5 63
Plant 1 65
Plant 8 67
Summary 70
CPE Findings 70
CCP Findings 70
References 71
APPENDICES
APPENDIX A CT Values for Inactivation of Giardia and Viruses by Free CI2 A-1
APPENDIX B Classification System, Factor Checklist, and Definitions for
Assessing Performance Limiting Factors B-1
APPENDIX C Data Collection Forms C-1
APPENDIX D Sample CPE Scheduling Letter D-1
APPENDIX E Sample CPE Report E-1
APPENDIX F Sample Special Study F-1
APPENDIX G Sample Water Treatment Plant Operating Procedure G-1
APPENDIX H Daily and Monthly Process Control Sheets for a
Small Direct Filtration Plant H-1
APPENDIX I Sample Jar Test Procedure 1-1
APPENDIX J Design-Related Performance Limiting Factors Identified in Actual CPEs J-1
APPENDIX K Chemical Feed Calculations K-1
APPENDIX L Sample CCP Summary Report L-1
vi
-------
LIST OF FIGURES
Figure 1 -1. Methodology for achieving plant compliance with SWTR 3
Figure 2-1, Major unit process evaluation approach 5
Figure 2-2. Performance potential graph 7
Figure 2-3. Conceptual performance potential graph 7
Figure 2-4. Typical plant finished water turbidity profile 11
Figure 2-5. Percentile plot of finished water turbidity 12
Figure 2-6. Filter effluent turbidity versus time 13
Figure 2-7. CPE/CCP schematic of activities 20
Figure 2-8. Schematic of CPE activities 21
Figure 2-9. Flow schematic of plant in CPE case study 28
Figure 2-10. Performance potential graph for CPE case study 30
Figure 3-1. Relationship of performance-limiting factors to achieving a performance goal 34
Figure 3-2. Typical scheduling of CCP activities 35
Figure 3-3. Action-Implementation plan 36
Figure 3-4, Special study format 36
Figure 3-5. Trend chart showing relationship of raw, settled, and filtered water 37
Figure 3-6. Velocity gradient versus rpm at various temperatures (°C) for a
2-liter square beaker, using a Phipps and Bird stirrer 38
Figure 3-7. A process control sampling and testing schedule for a small
water treatment plant 41
Figure 3-8. Finished water quality achieved during conduct of a CCP 46
Figure 3-9. Finished water quality achieved during the CCP case study 48
Figure 4-1. Plant 2 turbidity profile before and after backwash 56
Figure 4-2. Finished water turbidity versus time 56
Figure 4-3. Filter effluent turbidity versus time, 105 minutes after backwash 57
Figure 4-4. Finished water turbidity versus time for 1-year period 57
Figure 4-5. Filter effluent turbidity versus time after backwash 58
Figure 4-6. Turbidity profile showing the impact of a malfunctioning filter
rate controller at Plant 2 59
Figure 4-7. Turbidity profile showing the impact of "bumping" a filter
with total flow during backwash of other filter at Plant 2 59
Figure 4-8. Performance impacting practice of water falling from
influent troughs onto the filter media 60
Figure 4-9. Turbidity profile showing the detrimental impact of dirty filter startup at Plant 8 61
Figure 4-10. Filter "C" turbidity during CPE 61
Figure 4-11. Filter Nos. 3 and 4 effluent turbidity versus time 62
Figure 4-12. Finished water turbidity versus time for Plant 5 64
Figure 4-13. Raw water turbidity versus time for Plant 5 65
Figure 4-14. Settled water turbidity versus time from the reactor clarifiers at Plant 1 66
Figure 4-15. Effluent turbidity versus time from the presedimentation pond for Plant 1 66
Figure 4-16. Finished water turbidity versus time for Plant 1 67
Figure 4-17. Settled water turbidity versus time for Plant 8 68
Figure 4-18. Finished water turbidity versus time for Plant 8 69
Figure 4-19. Raw water turbidity versus time for Plant 8 69
vii
-------
LIST OF TABLES
Table 2-1. Criteria lor Major Unit Process Evaluation Using the Performance
Potential Graph Rating System S
Table 2-2 Expected Removals of Ciardia Cysts and Viruses by Filtration 9
Table 2-3. Factors for Determining Effective Disinfection Contact Time
Based on Actual Basin Characteristics S
Table 2-4. Classification System for Prioritizing Performance-Limiting Factors 15
Table 2-5. Rating of the Unit Processes and Overall Plant for the Case Study 29
Table 4-1. Summary of Plants Where CPEs Have Been Conducted 51
Table 4-2. Summary of Major Unit Process Evaluations for Facilities
Where CPEs Were Conducted 52
Table 4-3. Overall Rating of Top 10 Factors Identified by 21 CPEs 53
Table 4-4. Categories for Rating Performance-Limiting Factors 53
viii
-------
CHAPTER 1
INTRODUCTION
PURPOSE
This handbook is an interim version ot a source docu-
ment for individuals responsible tor improving the perfor-
mance of existing surface water treatment plants using
conventional and direct filtration unit processes to
achieve compliance with the Surface Water Treatment
Rule (SWTR) (1). The SWTR covers all public water sys-
tems that use either surface sources as a raw water
supply or ground-water sources determined to be under
the direct influence of surface water. The regulation in-
cludes requirements for filtered and nonfiltered systems.
This handbook, however, addresses only the turbidity
and disinfection requirements of the SWTR tor those sys-
tems utilizing conventional and direct filtration. These
systems are required to produce a finished water turbidity
of 0.5 NTU in 95 percent of the monthly samples.
The SWTR also requires that disinfection be sufficient to
ensure that the total treatment processes achieve at least
99.9 percent (3-log) inactivation and'or removal of Giar-
dia lamblia cysts and at least 99.99 percent (4-log) inac-
tivation and/or removal of viruses as determined by the
State. Each State regulatory program will have to adopt
its own disinfection regulations that include an approach
to assure that these overall disinfection requirements are
met. The U.S. Environmental Protection Agency (EPA)
has published a guidance manual for the SWTR (2), that
outlines procedures that are considered effective in as-
suring that the disinfection requirements are met. Each
Slate will have the option of using the disinfection re-
quirements in the guidance manual or developing its own
approach. The guidance manual also indicates that,
while the 3-log and 4-log Inactivation and/or removals are
the minimum required, the number of logs of inactivation
and/or removals may need to be increased if the raw
water source is subjected to excessive contamination
from cysts and/or viruses. Cyst and virus removal credits
for the different types of treatment processes are also
provided in the guidance manual.
The handbook presents procedures for assessing a con-
ventional or direct filtration plant's capability of achieving
the 0.5 NTU turbidity requirement. A method is also
presented for projecting if a plant will be able to meet the
disinfection requirements in the SWTR guidance manual.
Though the handbook is not intended to describe cost
savings options or to present alternatives for designing
new facilities for expansion purposes (i.e., to provide in-
creased hydraulic capacity), in some cases the approach
described may result in cost savings arid/or increased
capacity.
BACKGROUND
Development of the Composite Correction Program
Approach
As a result of signiticant new regulations, many com-
munities constructed new wastewater treatment facilities
in the late 1960s and 1970s. After construction, monitor-
ing indicated that many of these facilities were not in
compliance with their discharge permit requirements. A
survey was conducted of over one hundred facilities to
identify the reasons for this noncompliance (3,4,5). The
survey revealed that operation and maintenance lactors
were frequently identified as limiting plant performance,
but it also disclosed that administrative and design fac-
tors were contributing to poor plant performance. Addi-
tionally, each plant evaluated had a unique list of multiple
factors limiting its performance.
Based on these findings, an investigative program was
developed to address performance-limiting factors at an
individual facility and to obtain improved performance.
Significant success was achieved in improving perfor-
mance at many wastewater treatment facilities without
major capital improvements (6). Ultimately, a handbook
was developed that formalized the evaluation procedures
as well as the correction ones (7). This handbook was
updated in 1989 to include specific low-cost modifications
that could be used to optimize an existing facility's perfor-
mance (8), and an "expert system" (POTW Expert) was
developed to supplement the handbook (9).
The Composite Correction Program approach, which is
the name utilized for the formal procedures developed for
wastewater, consists of two components, the Com-
prehensive Performance Evaluation (CPE) phase and the
Composite Correction Program (CCP) phase. A CPE is a
thorough review and analysis of a plant's design
capabilities and associated administrative, operation, and
maintenance practices. It is conducted to identify factors
1
-------
that may be adversely impacting a plant's capability lo
achieve optimal performance. Its major objective is to
determine it significant improvements in performance can
be achieved without major capital improvements. A CCP
is the performance improvement phase that is imple-
mented it the results from the CPE indicate lhal improved
performance can be achieved. During the CCP phase,
identilied tactors are systematically eliminated. The major
benefit of a CCP is that it optimizes the capability of exist-
ing facilities without the expense of major capital im-
provements.
Montana Demonstration Project
The State of Montana has used the CCP approach at
most of the mechanical wastewater treatment facilities in
the state. Results from these efforts showed dramatic im-
provement in compliance and provided State personnel
with significant insight concerning personnel and plant
capabilities and deficiencies. These results led Slate
personnel to initiate a program, with financial support
from EPA Region 8, to evaluate the effectiveness of
using the CCP approach at small water treatment
facilities using surface water supplies. From April 1988
until September 1990, nine CPEs and three CCPs were
completed. Through these efforts, each of the existing
facilities where CCPs were implemented were brought
into consistent compliance with the SWTR requirements
for finished water turbidity. Additionally, improved perfor-
mance was achieved at plants where only the evaluation
phase (CPE) of the program was completed. These im-
pacts on performance represented a definite improve
ment over the previous annual inspection program
results. Other findings and benefits of the approach have
been documented (10,11).
EPA Demonstration Project
EPA's Office of Drinking Water has been given the
responsibility by Congress of regulating the nation's
water systems to assure that they produce drinking water
that protects the public's health. To meet this objective, a
large number of drinking water regulations are being
promulgated and all public water systems are expected
to comply. The Agency, therefore, is looking for cost-
eflective methods to achieve compliance. Based on the
initial success of the Montana program, EPA decided to
further develop and demonstrate the approach to ensure
its applicability to other parts of the country. A coopera-
tive project was initiated between EPA's Office of Drink-
ing Water, Technical Support Division (TSD), and Office
of Technology Transfer and Regulatory Support, Center
for Environmental Research Information (CER1). This
project has allowed the conduct of an additional 12 CPEs
in the states of Ohio, Kentucky, West Virginia, Maryland,
Montana, and Pennsylvania; the preparation of a sum-
mary report (11) to document the initial findings; and the
development of this handbook.
SCOPE
A total of 21 CPEs and 3 CCPs provides the basis lor the
procedures presenled in this handbook The handbook is
an interim document and the methodology described will
be refined based on additional CPEs and CCPs con-
ducted over the next several years
Figure 1-1 depicts the methodology for improving plant
performance used in this handbook As a tirst step, it is
assumed that users of this handbook will be aware of the
SWTR and have recognized a need to evaluate ttie
capability of an existing water treatment facility to meet
the new requirements. Next, an evaluation approach
(described in Chapter 2) to project existing facility
capability is implemented. II improved performance arid
compliance appear possible through optimization of exist
irig facilities, then a systematic approach to address iden-
tified deficiencies (described in Chapter 3) is
implemented to achieve compliance. If compliance is not
achieved, facility modifications are recommended, such
that either 1) capital expenditures must be made at the
existing facility or 2) new facilities must be designed and
constructed. The CCP approach emphasizes modifying
existing facilities to meet desired performance at existing
water demands. If existing facilities are inadequate,
another approach must be utilized that includes activities
that assess the need lor increased capacity as well as
improved performance. The assessment may include an
alternative analysis that could lead to modification or
abandonment of present facilities.
The intended users of this handbook are utility managers,
consultants, regulatory personnel, and others associated
with the responsibility of achieving compliance or more
consistent performance from existing surface water treat-
ment plants using conventional or direct filtration unit
processes. The emphasis is on small plants serving
populations of less than 10,000 consumers. The perfor-
mance improvement activities are directed at achieving
compliance with the turbidity and disinfection require-
ments of the SWTR. There is limited emphasis on
removal of organics or other aspects of pending regula-
tions such as control of disinfection byproducts.
USING THE MANUAL
The text of the handbook parallels the two major steps of
the Composite Correction Program approach. Chapter 2
discusses the CPE, an evaluation technique to identify
causes of poor plant performance and to assess the
capability of existing facilities for achieving compliance.
This evaluation procedure is conducted to assess the
suitability of pursuing the next phase of performance im-
provement.
Chapter 3 describes implementation of the CCP phase,
which details methods ol optimizing existing facilities
2
-------
Figure 1-1. Methodology for achieving plant compliance with SWTR.
Comp.lcnce Possfcn
I Through
Optimization oi
Ex'stfng Fcctl'ties
VVIthcut Ma'or Ccps't
Expenditures
Conduct Plant
Evc'uation to
idenijfy
Reasons ?or
Non-
Compliance
WIP Out cf
Compliance
With SWT*
Existing FociMsec
Optimized
Ccrr.plfcncfl
Achieve c3?
/
Y/T? in
Compliance
u
Exlst'ng Facilities
inadequate—Mcjor
Copftol Expenditures
Recutred
Abandon Ex!s1hg
Focillties ond
Construct New
pacr3:tlea or Modify
Existing FocHltfes
New Facilities
Optimized
without major capital improvements. Procedures to ad-
dress design, operation, maintenance, and administrative
factors limiting performance are outlined. Implementation
of this phase ensures optimization of existing facilities;
and if compliance with applicable drinking water regula-
tions is not achieved, the design factors limiting perfor-
mance are identified.
Chapter 4 provides a summary of significant findings for
the Montana and EPA demonstration projects data base.
Impacts of CPEs and CCPs are presented using site-
specific examples to illustrate findings. The overall top
ranking factors limiting performance that were identified
at the 21 CPEs in 6 states are discussed and the con-
clusions based on these observations are presented. It
is significant that optimizing the performance of existing
facilities using the procedures developed in this prelimi-
nary handbook appear to offer a viable alternative for
many small water treatment facilities to meet the SWTR
turbidity requirements.
REFERENCES*
1. U.S. EPA. 1989. Surface Water Treatment Rule.
Federal Register, Vol. 54, No. 124, U.S. Environmen-
tal Protection Agency, 40 CFR, Parts 141 and 142,
Rules and Regulations, Filtration/Disinfection. June.
2. U.S. EPA. 1989. Guidance Manual for Compliance
with the Filtration and Disinfection Requirements for
Public Water Systems Using Surface Water Sources.
NTIS No. PB-90148016. Washington, DC: U.S. EPA.
October.
3. U.S. EPA. 1979. Evaluation of Operation and Main-
tenance Factors Limiting Municipal Wastewater
Treatment Plant Performance, EPA 600/2-79-034.
NTIS No. PB-300331. Cincinnati, OH: U.S. EPA,
Municipal Environmental Research Laboratory.
4. U.S. EPA. 1979. Evaluation of Operation and Main-
tenance Factors Limiting Biological Wastewater
Treatment Plant Performance. EPA 600/2-79-087.
NTIS No. PB-297491. Cincinnati, OH: U.S. EPA,
Municipal Environmental Research Laboratory.
5. U.S. EPA. 1980. Evaluation of Operation and Main-
tenance Factors Limiting Municipal Wastewater
Treatment Plant Performance-Phase II. EPA 600/2-
80-129. NTIS No. PB-81 -112864. Cincinnati, OH:
U.S. EPA, Municipal Environmental Research
Laboratory.
6. U.S. EPA. 1979. A Demonstrated Approach for Im-
proving Performance and Reliability of Biological
Wastewater Treatment Plants, EPA 600/2-79-035.
NTIS No. PB-300476. Cincinnati, OH: U.S. EPA.
7. U.S. EPA. 1984. Improving POTW Performance Using
the Composite Correction Program Approach. EPA
625/6-84-008. NTIS No. PB-88184007. U.S. EPA
Center for Environmental Research Information. Oc-
tober.
8. U.S. EPA. 1989. EPA Technology Transfer Hand-
book: Retrofitting POTWs. EPA 625/6-89-020. NTIS
No. PB-90182478. U.S. EPA Center for Environmen-
tal Research Information. July.
3
-------
9. U.S. EPA. 1990. Expert System - POTW Expert, Ver-
sion 1.0 and User Documentation - POTW Expert,
Version 1.0. EPA 625/11-90/001. Prepared by
Eastern Research Group, Inc. and Process Applica-
tions, Inc. for U.S. EPA Center for Environmental Re-
search Information. September.
10. Renner, R.C., B.A. Hegg, and D.L. Fraser. 1989.
Demonstration of the Comprehensive Performance
Evaluation Technique to Assess Montana Surface
Water Treatment Plants. Presented at the 4th Annual
ASDWA Conference, Tucson, Arizona. February.
11. U.S. EPA. 1990. EPA Summary Report: Optimizing
Water Treatment Plant Performance with the Composite
Correction Program. EPA 625/8-90-017. U.S. EPA
Center for Environmental Research information.
March.
*When an NTIS number is cited in a reference, that refer-
ence is available from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
(703) 487-4650
4
-------
CHAPTER 2
COMPREHENSIVE PERFORMANCE EVALUA TION
OBJECTIVE
This chapter provides information on the evaluation
phase, the Comprehensive Performance Evaluation
(CPE), of the two-step process to improve the perfor-
mance of existing surface water treatment plants. A
primary objective of the CPE is to determine if significant
improvements in treatment performance can be achieved
without major capital expenditures.
CPE METHODOLOGY
A CPE focuses on the current condition of the facility (i.e.,
a "snapshot in time"), but also considers seasonal varia-
tions in raw water quality. A CPE involves several ac-
tivities: evaluation of the major unit processes,
assessment of plant performance, identification and
prioritization of performance-limiting factors, assess-
ment of the applicability of a followup Composite Correc-
tion Program (CCP), and reporting of the results of the
evaluation. Although these are distinct activities, some are
conducted concurrently with others. For example, evaluation
of major unit processes and identification of performance-
Figure 2-1. Major unit process evaluation approach.
limiting factors are generally conducted simultaneously. A
discussion of these activities follows.
Evaluation of Major Unit Processes
Overview
The major unit process evaluation is an assessment to
establish the potential of existing processes to achieve
desired performance levels. If the CPE indicates that the
major unit processes are potentially adequate, a major
plant upgrade or expansion may not be necessary and a
properly conducted CCP should be implemented to op-
timize performance. If, on the other hand, the CPE shows
that major unit processes are inadequate, utility owners
should consider modification of these processes as the
initial focus for achieving desired performance.
A rating system that allows the evaluator to project unit
process and associated overall plant type, either Type 1,
2, or 3, is used. This evaluation approach is graphically il-
lustrated in Figure 2-1. Type 1 plants are those where a
CPE shows that current performance difficulties are not
caused by limitations in size or capability of existing unit
Type 1
Major Unit Processes
Are Adequate
Type 2
Major Unit Processes
Are Marginal
Type 3
Major Unit Processes
Are Inadequate
Plant Administrators or
Regulators Recognize
Need To Evaluate or
Improve Plant Performance
I
CPE Evaluation
of
Major Unit Processes
t.
5
-------
processes. In these cases, problems are likely related to
plant operation, maintenance, or administration. Plants
categorized Type 1 are projected to be most likely to
achieve desired performance through implementation of
nonconstruction-oriented followup assistance (e.g., a
CCP as described in Chapter 3).
The Type 2 category is used to represent a situation
where marginal capacity of unit processes could poten-
tially prohibit a plant from achieving the desired perfor-
mance level. For Type 2 facilities, it is projected that
implementation of a CCP would lead to improved perfor-
mance, but might not achieve required levels without
facility modifications to the major treatment units.
Type 3 plants are those in which major unit processes
are projected to be inadequate to provide required
capacity for existing water demands. For Type 3 facilities,
major modifications are felt to be required to achieve con-
sistent compliance with applicable regulations. Although
other limiting factors may exist, such as the operator's
lack of process control capability or the administration's
unfamiliarity with plant needs, consistent acceptable per-
formance cannot be expected to be achieved until physi-
cal limitations of major unit processes are eliminated. If
severe public health problems exist with present plant
performance, officials may conduct activities to improve
plant performance as much as possible until major
modifications can be completed. A boil order or water
restrictions may have to be implemented until modifica-
tions are completed and performance is improved.
Owners with a Type 3 plant could meet their performance
requirements by pursuing modifications of existing water
treatment facilities. However, depending on future water
demands, more detailed study of treatment alternatives,
rate structures, and financing mechanisms may be war-
ranted. CPEs that identify Type 3 facilities are still of
benefit to plant administrators in that the need for con-
struction is clearly defined. Additionally, the CPE
provides an understanding of the capabilities and weak-
nesses of existing operation and maintenance practices
and administrative policies.
Approach
Major unit processes are evaluated based on their
capability to handle current peak instantaneous flow re-
quirements. The major unit processes included in the
evaluation are flocculation, sedimentation, filtration, and
disinfection. These processes were selected for evalua-
tion based on the concept of determining if the "concrete"
(e.g., basin size) is adequate. The potential capacity of a
major unit process is not lowered if "minor modifications,"
such as providing chemical feeders or installing baffles,
could be accomplished by the staff. This approach is in
line with the CPE intent of assessing adequacy of exist-
ing facilities to determine the potential of nonconstruction
alternatives. Other components of the plant processes,
such as rapid mix facilities, are not included in the major
unit process evaluation but rather are evaluated
separately as factors that may be limiting performance.
These components can most often be addressed through
"minor modifications."
An approach using a "performance potential graph" has
been developed to evaluate the major unit processes. As
an initial step in the performance potential graph ap-
proach, the CPE evaluators are required to use their
judgment to project peak treatment capability for each of
the major unit processes. It is important to note that the
ratings are based on achieving optimum performance
from sedimentation, filtration, and disinfection such that
each process maintains its integrity as a "barrier" to the
passage of turbidity and/or cysts. This allows the total
plant to provide a "multiple barrier" to the passage of
pathogenic organisms into the distribution system. The
projected treatment capacity rating is then compared to
the peak instantaneous operating flow rate experienced
by the water treatment plant during the most recent 12
months of operation. If the most recent 12 months is not
indicative of typical plant flow rates, the evaluator may
choose to review a time period considered to be more
representative. The peak instantaneous operating flow is
utilized because it is necessary that high quality finished
water be produced on a continuous basis.
The comparison of projected treatment capacity to peak
instantaneous operating flow rate is made using a perfor-
mance potential graph, as shown in Figure 2-2. The
processes evaluated are shown on the left of the graph
and the various How rates assessed are shown across
the top. Horizontal bars on the graph depict projected
capacity for each unit process, and the vertical line repre-
sents the actual peak operating flow experienced at the
plant. Footnotes are used to explain the conditions used
to rate the unit processes.
The approach to determine whether a unit process is
Type 1, 2, or 3 is based on the relationship of the
horizontal bars to the peak instantaneous operating flow
rate. As presented in Figure 2-3, a unit process would be
rated Type 1 if its projected capacity exceeds the actual
peak demand, Type 2 if its projected capacity was 90 to
100 percent of actual peak demand, or Type 3 if its
projected capacity is less than 90 percent of actual peak
demand.
When rating the capability of a unit process, it is impor-
tant to consider several options that are available for
water treatment facilities. For example, if a unit process
receives a Type 3 rating, it may be able to achieve Type
2 or Type 1 status by reducing demand or by extending
the operating time and operating at a lower rate (e.g., if
the peak instantaneous operating flow rate of a plant is
only occurring over a 12-hour period, the plant may be
able to be operated at half the flow rate for a 24-hour
period). In addition, it may be possible for a community to
6
-------
Figure 2-2. Performance potential graph.
Un*t PrOC055
0.2
flow, MOO
0.4 0.6
0.8
1.0
f-locculotion1
HDT, m'n
Sedimentation 2
SDR, gpm/sq ft
Filtration 3
HLR, gpm/sq t*.
Dlsin 'ect'on4
Cotilaci tfrno, rrfn
, Posh IntlanleftMue
Operating Row Rata,
Om< Pump - 300 gpn
<0.45 mgoj
1 Rated at 20 ml* hydrops detection ttrre (W07) - c^mei v« speed drive
would be edded.
2 Rated ot 0.3 gp.n/aq tt surface overflow rata (SOR) - 12.5-ft depth dlsecurcgee
higher raltnq.
5 Rated ct 4 qpm/sq ft hycroullc ;oadhg rote (*fl-R) - duo) media
' Ra'.ed ot CT = 127 with 2.4 mg/L Cj reefdyaJ, which re 100X of PRGK
90 — 1GG% of peak
I > icos
of peak
< 90% of peok
_ PmX Inttenteneoul
Opwefing Flow Rett
take steps to reduce demand by activities such as in-
creasing water rates, water rationing, or leak detection
and repair. In these instances, the potential to decrease
peak instantaneous operating flow rate needs to be care-
fully assessed by the evaluator in order to justify a
change in the unit process rating (see "Assessment of
Plant Operating Capacity," p. 13).
Rating Individual Unit Processes
The proposed criteria presented in Table 2-1 was used
as a basis to rate individual unit processes. There is a
wide range in the proposed criteria which can translate
into large differences in projecting unit process
capabilities. As such, using the performance potential
graph approach requires a great deal of judgment on be-
half of an experienced water treatment evaluator to
properly project capacity of a major unit process. A point
system has been drafted to project major unit process
capability. It will be utilized during future CPEs and
CCPs, modified as required, and included in the final ver-
sion of this handbook. Its purpose will be to allow
evaluators with different levels of experience to success-
fully project unit process capability.
Major unit processes are assessed, both with respect to
their capability to consistently contribute to an overall
plant treated water quality of 0.5 NTU and with respect to
providing consistent individual unit process performance.
Unit process performance capability is important to en-
sure that multiple barriers are maintained on a con-
tinuous basis. Specific performance requirements by
which each major unit process is assessed are described
in the following sections.
Fiocculation
Flocculation is evaluated primarily with respect to avail-
able hydraulic detention time. Required detention time for
adequate flocculation is highly variable depending on
water temperature and turbidity. For example, at plants
where water temperatures of less than 5°C (41 °F) occur,
floe formation can be delayed by the cold water. In these
instances, longer (30- to 40-minute) detention times may
be assessed to be required. Consideration can be given
to influent turbidity loads and whether or not the plant
could be operated in a direct filtration mode without floc-
culation. If temperature and turbidity factors are not as
severe, detention times as low as 10 minutes could be
assessed to be adequate. Because of these variables,
the evaluator must use judgment when rating the re-
quired hydraulic detention time of the flocculation basins.
Consideration is also given to the number of floccula-
tion stages, with a minimum of three considered
desirable. The availability of variable energy input to
control flocculation is also considered. However,
since variable mixing energy and staging can often
be added through minor modifications, these items
are not considered as significant in the capacity
rating. If adequate basin volume is available (e.g.,
typically a Type 1 unit process), a one-stage floc-
culation basin may result in a Type 2 capability
rating, and followup CCP activities would be required
to establish if additional baffling or flocculator drives
were necessary to improve performance.
Sedimentation
Sedimentation basin capacity is projected primarily based
on surface overflow rate with consideration given for
depth and sludge removal characteristics. In general,
shallow basins (e.g., less than 3 to 3.7 m [10 to 12 ft])
would receive a rated capacity based on the lower sur-
face overflow rates shown in Table 2-1. Criteria are
shown for rectangular and upflow units used for softening
and turbidity removal, and for units equipped with tube
settlers or lamella plate separators. Sedimentation basins
are assessed based on achieving a maximum settled
water turbidity of 2 NTU on a continuous basis with all raw
water qualities, to ensure the integrity of the sedimentation
process as a viable barrier in the treatment scheme.
7
-------
Table 2-1.
Criteria for Major Unit Process Evaluation
Using the Performance Potential Graph Rating
System (1,2,3,4)
UNIT PROCESS
Flocculation
HDT (min)
G sec "1
Stages
Sedimentation
SOR
Conventional Rectang
Turbidity
Softening
10-40
10-75
2-3
lar m3/m2/d (gpm/ft2)
29-41
29-59
Upflow Units, m3/m2/d (gpm/ft?)
Turbidity 29-41
Softening 29-59
Tube Settlers', m3/m2/d (gpm/ft2)
Turbidity 59-117
Softening 88-147
Lamella Plates
Turbidity/Softening,
(0.5-
(0.5
0.7)
1.0)
(gpm/ft )
m3/m2/d
Depth, m (ft)
Filtration
Filter Rate, m3/m2/d (gpm/ft?)
Mono Media
Dual/Mixed Media
Water Backwash Rate,
m3/m2/d (gpm/ft2)
Backwash Duration (min)
Disinfection
<235
3.6 -4.9
59
235
¦ 176
¦470
880- 1,173
(0.5 - 0.7)
(0.5 - 1.0)
(1.0-2.0)
(1.5-2.5)
(<4.0)
(12 - 16)
(1 -3)
(2-8)
(15-20)
10-15
(See "Filtration," below).
Based on tube settler area.
Filtration
Filters are rated based on hydraulic loading rates, with
consideration given to media type. For example, a mono-
media sand filter may be assessed at a maximum rate of
118 m3/m2/d (2 gpm/ft2) because of the tendency of this
filter to surface blind by removing particles at the top of
the filter media; whereas a dual or mixed media filter may
be assessed at a rate of 235 to 470 m3/m2/d (4 to 8
gpm/ft2) because of its ability to accomplish particle
removal throughout the depth in the anthracite layer.
Using the anthracite layer allows higher filtration rates to
be achieved while maintaining excellent filtered water
quality. It is noted that filtration capacity ratings can be,
and often are, restricted to certain maximum values be-
cause of existing State criteria. In these cases, State
criteria are used to project filter treatment capability.
Limitations in media depth and backwash facilities also
impact the selected loading rate for projecting a filter's
capacity. Limitations in these areas bias the rating toward
more conservative values within each range. Inadequate
backwash or surface wash facilities and media integrity
are also assessed as factors limiting performance. It is
noted that deficiencies in these areas can often be ad-
dressed through minor modifications and therefore are
assessed to have a lesser impact than hydraulic loading
rate.
Filters should be assessed based on their capability to
achieve a treated water quality of less than 0.1 NTU on a
continuous basis to ensure the integrity of the filtration
process as a viable barrier in the treatment scheme. This
is less than the 0.5 NTU standard, but operation of filters
to produce filtered water quality of less than 0.1 NTU is
not difficult to attain, makes possible achieving a 0.5 NTU
standard 95 percent of the time, and provides greater
confidence that pathogens are being removed prior to the
last barrier, disinfection.
Disinfection
Assessment of disinfection capability with respect to the
SWTR is difficult because specific requirements for
plants that provide filtration are not included in the rule.
The rule requires a minimum of 99.9 percent (3-log) inac-
tivation and/or removal of Giardia lamblia cysts and at
least 99.99 percent (4-log) inactivation and/or removal of
viruses. Each State is required to develop their own
regulations to assure that these levels of disinfection will
be achieved.
EPA has published a guidance manual that presents an
approach to assure that required levels of disinfection are
achieved (6). The approach uses the concept of assess-
ing the product of the concentration of the disinfectant C
times the actual time T that the finished water is in con-
tact with the disinfectant. CT values are provided in the
guidance manual that will provide various log removals
for different temperatures, pHs, and disinfectant
residuals. The guidance manual also indicates that, while
the 3-log and 4-log inactivation and/or removals are the
minimum required, the number of logs of inactivation
and/or removals may need to be increased if the raw
water source is subjected to excessive contamination
from cysts and/or viruses. This means that, in certain
situations, greater than a 3-log total removal of cysts may
be needed to assure adequate disinfection. Cyst and
virus removal credits for the different types of treatment
processes are also provided in the guidance manual.
The following presents procedures for assessing the
capability of a plant to meet the disinfection requirements
based on the CT values in the SWTR guidance manual.
Procedures are presented for both pre- and postdisinfec-
tion with predisinfection defined as adding the disinfec-
tant ahead of the filters and postdisinfection defined as
adding the disinfectant just after the filters. Whether or
not plants will be able to use predisinfection will depend
on how the States adopt their disinfection requirements.
Some may not allow predisinfection because of concerns
with disinfection byproducts and the possible ineffective-
ness of disinfectants in untreated waters. Other States
may choose to allow predisinfection because of concerns
with the capabilities of the postdisinfection systems to
8
-------
provide the required levels of cyst and virus inactivation
and/or removal. Both procedures are presented, not to
endorse the use of prechlorination, but to acknowledge
that in some cases the practice may be considered pru-
dent. Future regulation of disinfectant residuals and disin-
fection byproducts may also affect the use of
predisinfection. Since each State is required under the
SWTR to adopt its own disinfection requirements, these
procedures may have to be modified when evaluating
plants in different States.
Postdisinfection:
• Project the log reduction required by water treatment
processes based on the raw water quality or water-
shed characteristics. State health departments may
have established these values for a specific plant. If
not, the standard requirement for a watershed of
reasonable quality is a 3.0 log reduction of Giardia
cysts. A 4 or more log reduction may be required for
an unprotected watershed exposed to factors such as
wastewater treatment effluents.
• Project the log reduction capability of the existing
treatment plant. Judgment is required to project the
ability of existing processes to perform at the peak in-
stantaneous operating flow rate. Expected removals
by various types of filtration plants are presented in
Table 2-2. As shown, a 2-1/2 log reduction may be al-
lowed for a conventional plant with adequate unit treat-
ment process capability (e.g., Type 1 units preceding
disinfection).
• Select a required CT value from the tables in the
SWTR guidance document based on the required log
reduction, the log reduction capability of the plant, the
maximum pH and minimum temperature of the water
being treated, and the projected maximum chlorine
residual that could be used in the system. The
projected chlorine residual is based on the chlorine
dose considering disinfection system capability and
the maximum residuals tolerated by the consumer.
The maximum chlorine residual utilized in the evalua-
tion should be 2.5 mg/L free residual, based on re-
search that indicated contact time is more important
than disinfectant concentration at free chlorine
residuals above 2.5 mg/L (7). CT values for inactiva-
tion of Giardia cysts and viruses by free chlorine are
presented in Appendix A.
• Select an effective volume of the existing clearwell
and/or distribution pipelines to the first user. Effective
volume refers to the volume of basin or pipeline that is
available to provide adequate contact time for the dis-
infectant. Adequate time is referred to in the regula-
tions as Tio, which is the time it takes 10 percent of a
dye or tracer to be detected at the basin outlet after it
is injected into the basin influent flow. If a tracer study
has been conducted, the results should be utilized in
Table 2-2. Expected Removals of Giardia Cysts and
Viruses by Filtration (5)
Expected Log Removals
Filtration Giardia Viruses
Conventional 2.5 2.0
Direct 2.0 1.0
Slow Sand 2.0 2.0
Diatomaceous Earth 2.0 1.0
determining the effective contact time. If tracer studies
have not been conducted, the effective volume upon
which contact time will be determined can be calcu-
lated by multiplying the nominal hydraulic detention
time by a factor. For example, an unbaffled clearwell
may have an effective volume of only 10 percent (fac-
tor = 0.1) of actual basin volume because of the poten-
tial for short circuiting; whereas, a transmission line
could be based on 100 percent of the line volume to
the first tap because of the plug flow characteristics A
summary of factors to determine effective volume ver-
sus actual volume based on baffling characteristics is
presented in Table 2-3. Typically, tor unbaffled clear-
wells a factor of 0.1 has been used because of the fill
and draw operational practices (e.g., backwashing,
demand changes) and the lack of baffles. A factor of
0.5 has been used when calculating the effective
volume of well baffled flocculation and sedimentation
basins when rating prechlorination, and a factor of 1.0
has been used for pipeline flow. However, each disin-
fection system must be assessed on individual basin
characteristics, as perceived by the evaluator. Caution
is urged when using a factor from Table 2-3 of greater
than 0.1 to project additional disinfection capability for
basins. The limited amount of tracer test information
Table 2-3. Factors for Determining Effective Disinfec-
tion Contact Time Based on Actual Basin
Characteristics (5)
Baffling Condition
Factor
Baffling Description
Unbaffled
0.1
Nono; agitated basin,
high inlet and outlet flow
velocities, variable water level
Poor
0.3
Single or multiple unbaffled
inlets and outlets, no
intra-basin baffles
Average
0.5
Baffled inlet or outlet with
some intra-basin baffling
Superior
0.7*
Perforated inlet baffle,
serpentine or perforated
intra-basin baffles, outlet weir
or perforated weir.
Excellent
0.9*
Serpentine baffling
throughout basin.
Perfect (plug flow)
1.0
Pipeline flow
'Based on hydraulic detention time at minimum operating
depth.
9
-------
available indicates that actual contact times in typical
full-scale clearwelis are close to 10 percent of theoreti-
cal. Increasing this factor tor basins where special baf-
fles have not been installed is not recommended
unless tracer test information is available.
• Using these parameters, calculate a detention time
(e.g., CT value divided by projected chlorine residual)
to meet the required CT. Compare this value to the
available detention time at peak instantaneous operat-
ing flow (utilize the effective volume previously deter-
mined) to assess the performance capability of the
postdisinfection process. Example calculations are
presented in the case study on p. 27.
Predisinfection:
The following procedure has been developed for
predisinfection based on the requirements in the SWTR
guidance manual published by the EPA. The procedure
has only been used to determine the additional disinfec-
tion capability provided predisinfection is actually being
practiced at the utility being evaluated. When predisinfec-
tion is practiced, the performance potential graph should
be developed with two bars for disinfection: one including
predisinfection and one without. This allows the plant
owners to assess capability if predisinfection was ex-
cluded (e.g., disinfection byproducts became a limitation
given the new regulations).
• Project the log reduction required by water treatment
processes based on the raw water quality or water-
shed characteristics as presented in the postdisinfec-
tion procedure.
• Project the log reduction capability of the existing
treatment plant as presented in the postdisinfection
procedure. Expected removals by various types of
filtration plants are presented in Table 2-2.
• Select a required CT value for both pre- and postdisin-
fection from the tables in the SWTR guidance docu-
ment based on the required log reduction, the log
reduction capability of the plant, the maximum pH and
minimum temperature of the water being treated, and
the projected maximum chlorine residual. The required
CT values may be different for the pre- and postdisin-
fection conditions if different temperatures, pHs, and
chlorine residuals exist for both conditions. For ex-
ample, addition of lime or soda ash to increase the pH
of finished water would change the required CT value
for postdisinfection relative to predisinfection.
NOTE: The projected chlorine residuals are selected
for pre- and postdisinfection based on the chlorine
dose considering disinfection system capability and
maximum residuals considered practical. As dis-
cussed in the postdisinfection procedure, a 2.5 mg/L
free chlorine residual is considered maximum for
postdisinfection. A 1.5 mg/L free chlorine residual is
used as the maximum for predisinfection unless ac-
tual plant records support selection of a higher
residual. CT values for inactivation of Giardia cysts
and viruses are presented in Appendix A.
Select an effective volume available to provide adequate
contact time for both pre- and postdisinfection. For
postdisinfection, use the same effective volume used
when assessing the capabilities of postdisinfection alone.
For predisinfection, assess which basins and lines will
provide contact time. These are typically the flocculation
and sedimentation basins, but could include raw water
transmission lines if facilities exist to inject chlorine prior
to the plant. Filters are normally riot included because of
the short detention times typically inherent in the filters
and the reduction in chlorine residual that often occurs
through filters. The actual basin volumes should be con-
verted to effective volumes by applying factors described
in Table 2-3 and discussed previously in the postdisin-
fection procedure.
Calculate a flow rate where the plant will achieve the
required CT values for both pre- and postdisinfection
using the formula below. Use this flow rate to establish
the pre- and postdisinfection system capability on the
performance potential graph.
Q-.
Cpre X Vpre
CTrca-,
\ (
; +
rcq-pre
Cpost X Vpost
CTroq post
where
Q = Flow rate where required CT is met.
CTroq = CT requirements from Tables in Appendix
A for pre- and postdisinfection conditions.
Vpre = Effective volume for predisinfection system.
Vpost = Effective volume for postdisinfection system.
Cpre = Free chlorine residual used for
predisinfection system.
Cpost = Free chlorine residual used for
postdisinfection system.
Conducting Performance Assessment
The performance assessment step uses existing and on-
site data evaluations to determine if unit process and
total plant performance have been optimized. Perfor-
mance of each unit process, flocculation/sedimentation,
filtration, and disinfection, are assessed to ensure that
multiple barriers are in place such that continuous op-
timum performance is achieved. This includes assess-
ment of the presence of short periodic breakdowns in
10
-------
treatment caused, for example, by "bumping a filter"
which releases previously trapped particles. Such a prac-
tice could have a significant health effect if the particles are
Giardia or Cryptosporidium cysts and therefore represents a
poorly operated facility. Using these criteria, it is possible to
identify poorly performing unit processes and thus poorly
performing plants, even though these facilities have
reported compliance with turbidity regulations.
Plant Operating Records
During the evaluation of plant data, laboratory quality
control (especially calibration of turbidimeters) and
sample locations should be reviewed to ensure that
proper sampling and analysis have provided data that are
truly representative of plant performance. Plant operating
records for the most recent 12 months or other repre-
sentative period can then be reviewed and evaluated.
Data should be collected and evaluated for raw water,
settled water, and finished water, and for individual filter
effluent, if available. The use of a computer spreadsheet
to tabulate and graph the turbidity data versus time and
to conduct a frequency analysis of the data can assist in
evaluating performance, A good indication of the stability
Figure 2-4. Typical plant finished water turbidity profile.
of plant operation can often be obtained from comparing
plots of raw water, settled water, and finished water turbidity
for the 12-month evaluation period. When comparing these
data, the evaluator should look for consistent settled and fil-
tered water turbidities even though raw water quality may
vary significantly. Performance for filters and sedimentation
basins should be judged acceptable based on achieving fil-
tered water and settled water turbidities consistently less
than 0.1 NTU and 2 NTU, respectively, even though raw
water quality may fluctuate widely.
A frequency analysis allows the evaluator to determine
the percent of time that raw, settled, or finished water
quality achieves a certain turbidity. This information can
be used to predict the variability of raw water turbidity
and the performance of sedimentation and filtration unit
processes. The frequency plots of finished water quality
with 12 months of data are useful tools to project a
plant's compliance capability with SWTR requirements.
The 12-month analysis is desirable because it includes
on a single graph the impacts of seasonal variations and
provides a good indicator of long-term performance.
A typical plant filtered water turbidity plot is shown in
Figure 2-4. The variability of finished water turbidity
oj
) '¥ I 1 I—I 1 1 I 1 1 I 1 ——i—i—i—i—i——i—t—i—(—I-
-i—(- > i
in
=)
H
>s
¦P
_Q
3
m
G O
O
W
¦ S>
o
¦ °% *
^ <9
¦1 _££>
0
# §
Q O
O
c>
oo o
"IP
Gh°
og> O
£> ?
o o
o
Present
Requirement
^
Q—
Q&— U~
2-S-O^-
o° © ° o o£> & ^
0 ° 0 ^
o
° GDqc£0
"T ~~P~W
_ ~ kj i-uiure
CP O © jq Requirement (§*
O
°
s —t—i—(—i—i—|—i i i—i i |—i—i i i—h
-i—i—(—t-
H 1 1 1 H
JRN89
FEB
MRR
RPR
Days
MRY
JUN
JUL
11
-------
shown in this plot is unacceptable and shows that plant
performance has not been optimized. The frequency plot
of these same data (Figure 2-5) projects that the plant, as
presently operated, would not meet the SWTR (8) re-
quirement that 95 percent of samples collected each
month achieve a turbidity of 0.5 NTU or less. In this ex-
ample, the plant was only achieving a 1.1 NTU level at
the 95th percentile.
Despite the usefulness of existing data, plant evaluations
conducted to date have revealed that operating records
often do not represent actual performance because of im-
proper turbidimeter calibration and the location and
timing of sample collection. An example of nonrepresen-
tative sampling is collecting turbidity samples from the
clearwell, once each day. This sample can be further
biased by collection immediately after the plant has been
placed in operation. Samples collected in this fashion
have not been found to be representative of actual per-
formance. It is noted that some existing State drinking
water regulations do not require more stringent sampling
than once per day and also do not provide clear
guidelines concerning representative sampling. As such,
the above techniques may fall within existing State
Figure 2-5. Percentile plot of finished water turbidity.
guidelines. The SWTR requires turbidity sampling every
4 hours; however, CPE results have indicated that even
this may not be frequent enough to identify significant
short-term excursions from acceptable performance.
Continuous monitoring and recording of turbidity from
each filter has allowed identification and correction of
short-term turbidity excursions.
Special Study Data
To supplement existing plant data, special studies should
be performed during a CPE. A typical special study is a
time versus turbidity profile conducted on filters before
and after backwashing. Acceptable performance is
judged to be an increase in filtered water turbidity of less
than 0.2 to 0.3 NTU for less than 10 minutes following a
backwash. An example of unacceptable filter perfor-
mance is depicted in the turbidity versus time graph
presented in Figure 2-6. As shown, a significant
breakthrough of turbidity occurred after the backwash
(e.g., turbidity increased to 38 NTU). Samples taken from
the clearwell at the same time showed turbidity values of
6.3 NTU, far in excess of current or proposed regulatory
criteria. Other special studies include developing a tur-
bidity profile after starting a dirty filter, profiling turbidities
12
-------
Figure 2-6. Filter effluent turbidity versus time.
in
tn
ts JL
^ m
ZD
Z
w ™
£ B
OJ
U1
U1
Present
Requ i rement
0 3 G 9 12 15 18 21 24 27 30
T i me (m i n )
from the sedimentation basins, and continuous monitor-
ing of turbidities from individual fillers and the clearwell.
The use of a continuous recording turbidimeter in the
conduct of special studies provides more accurate results
and often reveals performance problems, such as those
caused by a malfunctioning filler rale control valve, thai
may nol be noticed through conventional grab sampling.
In a plant that has multiple filters, it is advantageous to
collect grab samples from individual filters for turbidity
analysis before selecting the filter that is to be monitored
by the continuous recording turbidimeter.
Assessment of Plant Operating Capacity
Another important aspect of the performance assessment
is a determination of peak instantaneous operating flow
rale. Accurate assessment of instantaneous peak operat-
ing flow rate is important for two reasons. First, this is the
flow rate against which the capability of each of the major
unit processes is assessed during conduct of the major
unit process evaluation using the performance potential
graph. Based on this assessment, the unit process type
is projected, which determines if major construction will
be required at the plant. Second, evaluation of the peak
instantaneous operating flow rate and plant operating
time allows the evaluator to determine it plant perfor-
mance can be improved by reducing the plant flow rate
and extending the plant operating time. This capability
has existed at many plants evaluated to date, allowing a
plant to be projected as capable of being brought into
compliance with SWTR requirements without major
facility improvements.
Peak instantaneous operating flow rate has to be iden-
tified through review of operating records and observa-
tion of operation practices and flow control capability.
Flow records can be reviewed to determine the peak
daily water demand. Through discussions with the
operating staff, it can be determined whether the peak
demand occurred when the plant was operated for a lull
24-hour period. If the peak demand was for a full 24-hour
period, then that flow rale equals the peak instantaneous
operating flow. If not, peak instantaneous operating flow
is actually the peak flow rate at which the plant is
operated. For example, a plant may have two constant
speed raw water pumps each rated at 63 L7s (1,000
gpm). If only one is operated at a time, the peak instan-
taneous flow rate would be established at 63 Us (1,000
gpm). If operating personnel indicate that a control valve
is used to throttle plant flow to 47 L/s (750 gpm) on a
continuous basis, the peak instantaneous flow rate would
be established at 47 L7s (750 gpm).
13
-------
Identification and Prioritization of
Performance-Limiting Factors
Identification of Performance-Limiting Factors
A significant aspect of any CPE is the identification of fac-
tors that limit the existing facility's performance. This step is
critical in defining the focus of followup efforts. To assist in
factor identification, a list of 65 different factors that could
potentially limit water treatment plant performance is
provided in Appendix B. These factors are divided into
broad categories of administration, maintenance, design,
and operation. Definitions of each factor are provided. This
list and definitions have been updated and modified based
on the results of the 21 water treatment plant CPEs that
have been conducted, and is provided for convenience and
reference. If alternate names or definitions provide a clearer
understanding to those conducting the CPE, they can be
used. However, if different terms are used, each factor
should be defined and these definitions should be readily
available to those conducting the CPE and interpreting the
results. It is desirable to adopt a consistent list to allow com-
parison from plant to plant. Note that the list includes factors
on capacity of major unit processes. If the evaluation of
major unit processes results in a Type 2 or 3 classification,
these results can then be documented in the overall list of
factors identified as limiting an existing plant's performance.
A factor should only be identified if it impacts plant perfor-
mance. As such, an observation that a factor does not
meet a particular "industry standard" (e.g., a documented
preventive maintenance program or good housekeeping
practices) does not necessarily indicate a performance-
limiting problem. An actual link between poor plant per-
formance and the identified factor must exist. Properly
identifying a plant's unique list of factors is difficult be-
cause the actual problems in a plant are often masked.
This concept is illustrated in the following discussion:
A review of plant records revealed that a convention-
al water treatment plant was periodically producing
finished water with a turbidity of about 1.2 NTU. The
utility, assuming that the plant was operating beyond
its capability, was beginning to make plans to expand
both the sedimentation and filtration facilities of the
plant. Special studios conducted as part of a CPE
revealed that settled water and finished water tur-
bidities averaged about 15 NTU and 3.5 NTU,
respectively. Filtered water turbidities peaked at 25
NTU for short periods following a filter backwash. Ini-
tial observations could lead to the conclusion that the
plant's sedimentation and filtration facilities were in-
adequately sized. However, further investigation
revealed the poor performance was caused by the
operator adding coagulants at dosages 200 percent
higher than required, leading to formation of a milky
pin floe that would not settle or filter, and operating
the plant at its peak capacity for only 8 hours each
day, resulting in the washout of solids from the
sedimentation basins. It was determined that im-
plementing proper process control of the plant (e.g.,
turbidity testing and jar testing for coagulant control)
and operating the plant at a lower flow rate for 16
hours each day would allow the plant to continuously
achieve acceptable finished water quality. It was fur-
ther determined that the reason the plant was not
operated for longer periods of time was an ad-
ministrative policy that limited plant staff to one per-
son, which made both 16-hour and weekend
coverage difficult. Staffing with one operator would
not allow continuous successful operation of the plant
because there would be periods of time when neces-
sary process control adjustments could not be made.
It was concluded that four factors contributed to the poor
performance of the plant:
1. Operator Application of Concepts and Testing to
Process Control. Inadequate operator knowledge to
determine proper coagulant doses and to set chemi-
cal feed pumps to apply the correct chemical dose.
2. Administrative Policies. Restrictive administrative
policy that prohibited hiring an additional operator to
allow reduced plant operating flow rate by increasing
operating time.
3. Process Control Testing. Inadequate test equipment
and sampling program to provide process control in-
formation.
4. Administrative Familiarity with Plant Needs. Poor ad-
ministrative guidance that resulted in a rate structure
that would not support the needs of the plant.
Given the above observations, plant expansion is not re-
quired.
The above discussion illustrates that a comprehensive
analysis of a performance problem is essential to identify
the actual performance-limiting factors. If the initial con-
clusions regarding sedimentation and filtration capacity
had been pursued, improper corrective actions in the
form of unnecessary expenditures would probably have
occurred. Instead, addressing the operational and ad-
ministrative factors identified would allow the plant to
produce an acceptable finished water on a continuous
basis without major expenditures for construction.
Prioritization of Performance-Limiting Factors
After all performance-limiting factors are identified, they
are prioritized in order of their adverse effect on achieve-
ment of desired plant performance. This prioritization es-
tablishes the sequence and/or emphasis of followup
activities necessary to optimize facility performance. For
example, if the highest ranking factors (i.e., those having
the most negative impact on performance) are related to
physical limitations in unit process capacity, initial correc-
14
-------
tive actions are directed toward defining plant modifica-
tions and obtaining administrative funding for their im-
plementation. If the highest ranking factors are process
control-oriented, initial emphasis of followup activities
would be directed toward plant-specific operator training.
Prioritization of factors is accomplished by a two-step
process. First, all factors that have been identified are in-
dividually assessed with regard to adverse impact on
plant performance and assigned an "A," "B," or "C" rating
(Table 2-4). The checklist of factors in Appendix B in-
cludes a column to enter this rating. The second step of
prioritizing factors is to list those receiving an "A" rating in
order of severity, followed by those receiving a HB" rating
in order of severity. "C" factors arc not prioritized.
"A" factors are major sources of a performance deficien-
cy and are the central focus of any subsequent improve-
ment program. An example "A" factor would be
sedimentation facilities that are inadequate to reduce the
turbidity loading to the filters at all times of the year, such
that desired finished water quality cannot be achieved.
Factors are assigned a "B" rating if they fall in one of two
categories:
1. Those that routinely contribute to poor plant perfor-
mance but are not the major problem. An example
would be insufficient plant process control testing
where the primary problem is that the staff does not
understand coagulation chemistry, how to run or in-
terpret jar tests, or the need for additional process
control testing.
2, Those that cause a major degradation of plant perfor-
mance, but only on a periodic basis. Typical ex-
amples are sedimentation basins that cause periodic
serious problems during spring runoff or a short floc-
culation detention time that limits floe formation
during cold water periods.
Factors receive a "C" rating if they contribute to a perfor-
mance problem, but have minor effect. For example, if
raw water was being sampled from the rapid mix after
chemical feed, it could indirectly contribute to poor perfor-
mance since raw water testing would not be repre-
sentative of actual conditions. The problem could be
easily corrected and would not be a major focus during
followup correction activities.
As a comparison of the different ratings, the example "A"
factor above (sedimentation) would receive a "B" rating if
the basin was only inadequate periodically, for example,
during a runoff event. The factor would receive a "C"
rating if the basin size and volume were adequate, but
minor baffling was required to improve its performance.
Typically, 5 to 15 factors are identified during a CPE.
The remaining 50 to 60 factors that are not identified as
performance limiting represent a significant finding. For
example, in the case presented under "Identification of
Table 2-4. Classification System for Prioritizing
Performance-Limiting Factors
Hating
A Major effect on long-term repetitive basis.
B Minimum effect on routine basis or major effect
on a periodic basis.
C Minor effect.
Performance-Limiting Factors" on p. 14, neither sedimen-
tation nor filtration was identified as a performance-limit-
ing factor. Since they were not identified, plant personnel
need not focus on the sedimentation basins or filters as a
problem, which would preclude spending large amounts
of capital to upgrade these facilities. Factors that are not
identified are also a source for providing recognition to
plant personnel for adequately addressing these potential
sources of problems.
Once each identified factor is assigned an "A," "B," or "C"
classification, those receiving "A" or "B" ratings are listed
on a 1-page summary sheet (see Appendix B) in order of
assessed severity on plant performance. The prioritized
summary list of factors provides a valuable reference for
the next step of the CPE, assessing the ability to improve
performance, and serves as the foundation for im-
plementing correction activities if they are deemed ap-
propriate.
All factors limiting facility performance typically may not
be identified during the CPE phase. It is often necessary
to later modify the original corrective steps as new and
additional information becomes available during conduct
of the performance improvement (CCP) phase.
Evaluation of Performance-Limiting Factors
Evaluation of administration, maintenance, design, and
operation factors occurs throughout the conduct of a
CPE. Following are some useful observations in identify-
ing factors in these areas.
Evaluation of Administration Factors
The evaluation of administrative performance-limiting fac-
tors is a subjective effort, primarily based on manage-
ment and staff interviews. In small plants the entire staff,
budgetary personnel, and plant administrators, including
a minimum of one or two elected officials, should be in-
terviewed. These interviews are more effective after the
evaluator has been on a plant tour and has completed
enough of the data development activities (including the
major unit process and performance assessment evalua-
tions) to become familiar with plant capabilities and past
performance. With this information, the evaluator is better
equipped to ask insightful questions about the existing
plant. To accurately identify administrative factors re-
quires aggressive but nonthreatening interview skills.
The evaluator must always be aware of this delicate
balance when pursuing the identification of administrative
factors.
15
-------
Budgeting and financial planning are the mechanisms
that plant owners/administrators generally use to imple-
ment their objectives. Therefore, evaluation of these
aspects is an integral part of efforts to identify the
presence of administrative performance-limiting factors.
Smaller utilities often have financial information combined
with other utilities, such as wastewater treatment, street
repairs, and parks and recreation. Additionally, nearly
every utility's financial information is set up differently.
Therefore, it is necessary to review information with the
assistance of plant and/or budgetary personnel to rear-
range the line items into categories understood by the
evaluator. Forms for comprehensively collecting plant in-
formation, including financial information, have been
developed and are presented in Appendix C. These
forms allow a consistency in development of financial in-
formation.
When reviewing financial information, it is important to
determine the extent of bond indebtedness of the com-
munity and whether the rate structure creates sufficient
revenue to adequately support the plant. Water system
revenues should provide an adequate number of fairly
paid staff and exceed expenditures enough to allow es-
tablishment of a reserve fund for future plant modifica-
tions.
Typically, all administrators verbally support goals of low
costs, safe working conditions, good plant performance,
and high employee morale. An important question that
the evaluator must ask is, "Where does treated water
quality fit in?" Often, administrators are more-concerned
with water quantity than quality, and this question can be
answered by observing the items implemented or sup-
ported by the administrators. If a $12 million dollar reser-
voir project is being implemented while the plant remains
unattended and neglected, priorities regarding quality
and quantity can be easily discerned.
Another important issue to assess is the administrator's
desire to create and maintain a "self-supporting" utility.
Sometimes small utility administrators create enough
debt to enable the utility to be eligible for government
grants. This can be especially damaging to the long-term
stability of the utility and to plant performance because it
allows few options for financing improvements that may
be necessary to meet future water treatment regulations.
An ideal situation is one in which the administrators func-
tion with the awareness that they want to achieve high-
quality finished water as the end product of their water
treatment efforts. Improving working conditions, providing
adequate numbers of qualified staff, towering treatment
costs, and other similar goals would be pursued within
the realm of first achieving high quality finished water.
At the other end of the spectrum is an administrative at-
titude that "We just raised rates 25 percent last year and
we can't afford to spend another dime on that plant; be-
sides my family used to drink untreated water from the
river and no one got sick." Administrators who fall into
this category, typically, are identified as contributing to in-
adequate performance during factor identification ac-
tivities.
Technical problems identified by the plant staff or the
CPE evaluator, and the potential costs associated with
these problems, often serve as the basis for assessing
administrative factors limiting performance. For example,
the plant staff may have correctly identified needed minor
modifications for the facility and presented these needs
to the utility manager, but had their requests declined.
The evaluator must solicit the other side of the story from
the administrators, to see if the administration is indeed
nonsupportive in correcting the problem. There have
been numerous instances in which operators or planl su-
perintendents have convinced administrators lo spend
money to "correct" problems that resulted in no improve-
ment in plant performance.
Administrators can directly impact performance of a plant
by providing inadequate staffing levels to provide for an
operator at the plant when the plant is in operation. In-
adequate plant coverage often results in poor perfor-
mance since no one is at the plant to adjust chemical
dosages relative to raw water quality changes. Another
area in which administrators can significantly, though in-
directly, affect plant performance is through personnel
motivation. A positive influence exists if administrators
encourage personal and professional growth through
support of training, tangible awards for initial or upgrading
of certification levels, etc. If, however, administrators
eliminate or skimp on essential operator training,
downgrade operator positions through substandard
salaries, or otherwise provide a negative influence on
operator morale, administrators can have a significant
detrimental effect on plant performance.
Evaluation of Design Factors
Data gathered during a plant tour, review of plant draw-
ings and specifications, completion of design information
forms in Appendix C, and the completed evaluation of
major unit process capabilities, including the performance
potential graph, provide the basic information needed to
assess design-related performance-limiting factors.
Often, to complete the evaluation, the evaluator must
make field investigations of the various unit processes.
Field evaluations or special studies should be completed
in cooperation with the plant operator. The evaluator
must not make any changes in equipment operation
unilaterally. Any field testing desired should be dis-
cussed with the operator, whose cooperation should be
obtained in making any needed changes. This approach
is essential since the evaluator may wish to make chan-
ges that could improve plant performance but could be
detrimental to equipment at the plant. The operator has
16
-------
worked with the equipment, repaired past failures, and
read the manufacturer's literature, and is in the best posi-
tion to ascertain any adverse impact of proposed changes.
Special studies are discussed in "Facilitator Tools" on p. 33.
Evaluation of Operational Factors
Operational factors are those that relate to the unit
process control functions. Significant performance-limit-
ing factors often exist in these areas (4,9,10). The ap-
proach and methods used in maintaining process control
can significantly affect performance of plants that have
adequate physical facilities.
A plant tour provides an opportunity to initially assess
process control efforts. For example, the process control
capability of an operator can be subjectively assessed
during a plant tour by noting if the operator recognizes
the unit process functions and their relative influences on
plant performance. A good grasp of process control is in-
dicated if this capability exists.
The heart of the operational factors assessment is the
process control testing, data interpretation, and process
adjustment techniques utilized by the plant staff. The
primary controls available to a water treatment plant
operator are flow rate; chemical selection and dosage;
and filter backwash frequency, duration, and rate. Other
controls include flocculation energy input and sedimenta-
tion sludge removal. Process control testing is necessary
to gain information to make decisions regarding these
available controls. Information to assist in evaluating
process control testing data interpretation and process
adjustment efforts is presented.
Plant Flow Rate. Plant flow rate dictates the hydraulic
loading rate on the various plant unit processes. In plants
that operate 24 hours each day, water demand dictates
water production requirements. However, many small
plants operate at maximum flow rates for short (e.g., 8-
hour) periods of time. If the operator is not aware that
operating for longer periods of time at a lower flow rate
could improve plant performance, an operations factor
may be indicated. Rapid increases in plant flow rate can
also have a significant effect on plant performance by
forcing particles through the filters.
Chemical Dose Control. Chemical coagulants and filter
and flocculant aids are utilized to neutralize charges on
colloidal particles and to increase the size of the particles
to allow them to be removed in sedimentation and filtra-
tion unit processes. Either overdosing or underdosing
these chemicals can result in a failure to destabilize small
particles, including pathogens, and allow them to pass
through the sedimentation and filtration processes. If dis-
infection is inadequate to eliminate the pathogens that
pass through the plant, a significant public health threat
exists. Chemicals used for stabilization, disinfection, taste
and odor control, and fluoridation must also be controlled.
The following are common indicators that proper chemi-
cal dose control is not practiced:
• Calibration curves are not available for chemical feed
pumps.
• The operator cannot explain how chemicals, such as
polymers, are diluted prior to application.
• The operator cannot calculate chemical feed doses
(e.g., cannot convert a mg/L desired dose to lb/day or
mL/min to allow proper setting of the chemical feeder).
• The operator cannot determine the chemical feeder
setting for various doses.
• The operator does not adjust chemical feed rates for
varying raw water quality conditions.
• Chemicals are utilized in combinations that have
detrimental effects on plant performance. An example
is the practice of feeding lime and alum at the same
point without consideration of the optimum pH for alum
coagulation.
• Chemical feed rates are not changed when plant flow
rate is adjusted.
• Chemical coagulants are not utilized when raw water
quality is good (e.g., less than 0.5 to 1.0 NTU).
Filter Control. The effectiveness of the filtration unit process
is primarily established by proper coagulant control;
however, other factors, such as hydraulic loading rate and
backwash frequency, rate, and duration, also have a sig-
nificant effect on filter performance. Some filters can per-
form at relatively high filtration rates (e.g., 8 gpm/ft2) if the
water applied is properly chemically conditioned (11,12).
However, because particles are held in a filter by relatively
delicate forces, rapid flow rate changes can drive particles
through a filter causing a significant degradation in perfor-
mance (4,11,12). Rapid rate changes can be caused by in-
creasing plant flow by bringing a high volume constant rate
pump online, by a malfunctioning filter rate control valve, or
by removing a filter from service for backwashing without
reducing overall plant flow.
Filters must be backwashed periodically to prevent ac-
cumulated particles from washing through the filter or to
prevent Ihe filter from reaching terminal headloss. Filters
should be backwashed based on effluent turbidity if
breakthrough occurs before terminal headloss to prevent
poor filtered water quality. For example, particles that are
initially removed by the filter are often "shed" when
velocities and shear forces increase within the filter as
headloss accumulates (e.g., filter becomes "dirty"). This
significant breakthrough in particles can be prevented by
washing a filter based on turbidity or particulate analysis.
Also inadequate washing, both in terms of rate and dura-
tion, can result in an accumulation of particles in the filter,
resulting in poor filtered water quality. When a filter is
continually returned to service with a significant amount
17
-------
of particles still within the media, these particles can ac-
cumulate to form mudballs. The accumulation of mud-
balls takes up effective filter surface area and raises the
filtration rate through those areas of the filter where water
can still pass. The filter can also reach a point where min-
imal additional particles can be removed because avail-
able storage sites within the media already have an
accumulation of filtered particles. The evaluator must
determine whether inadequate washing is caused by a
design or an operational limitation. Field evaluations,
such as bed expansion and rise rate, that can be con-
ducted to determine the capability of backwash facilities
are discussed beginning on p. 25.
The following are common indicators that proper filter
control is not practiced:
• Individual filter performance is not monitored.
• Rapid increases in overall plant flow rate are made
without consideration of filtered water quality.
• Filter performance after backwash is not monitored.
• Filters are removed from service without reducing
plant flow rate, resulting in the total plant flow being
directed to the remaining filters.
• Operators backwash the filters without regard for filter
effluent turbidity.
• Operators backwash at a low rate for a longer period
of time, or stop the backwash when the filter is still
dirty to "conserve" water.
• Filters have significantly less media than specified,
damage to underdrains or support gravels, or a sig-
nificant accumulation of mudballs; and these condi-
tions are unknown to the operating staff because there
is no routine examination of the filters.
• The purpose and function of the rate control device
cannot be described.
Process Control Activities. It is necessary for the opera-
tions staff to develop information from which proper
process adjustments can be made. At a minimum, a
method of coagulation control must be practiced, such as
jar testing. Samples of raw water, settled water, and in-
dividual filter effluent should be monitored for turbidity.
An operator who properly understands water treatment
should be able to show the evaluator a recorded history
of raw, settled, and filtered water quality and jar test
results; and be able to describe how chemical dosages
are determined and calculated, and how chemical
feeders are set to provide the desired chemical dose.
The operator should also be able to explain how chemi-
cal feed rates are adjusted, depending on raw water
quality.
The following are common indicators that required
process control activities are not adequately implemented
at a plant:
• Jar tests or other methods (e.g., streaming current
monitor, zeta potential, or pilot filter) of coagulation
control are not practiced.
• The operator does not understand how to prepare a jar
test stock solution and to administer various chemical
doses to the jars.
• The only testing being conducted is raw water turbidity
(daily) and finished water turbidity, as collected from a
clearwell sample on a daily basis.
• Settled water turbidities are not measured on a routine
basis (e.g., minimum of once each shift).
• Individual filtered water quality is not monitored.
• There are no records available documenting perfor-
mance of the individual sedimentation or filtration unit
processes.
Other Controls. Other controls available to the operator
include rapid mixing, flocculation energy input, and
sedimentation sludge removal. The following are in-
dicators that these controls are not fully utilized to im-
prove plant performance:
• The rapid mixer is shut down (e.g., to conserve
power).
• Variable speed flocculation drives are not adjusted
(e.g., they remain at the setting established when the
plant was constructed).
• There is no routine removal of sludge from sedimenta-
tion basins.
• There is no testing to control sludge quantities in a
reactor upflow sedimentation basin (e.g., routine
sludge withdrawal is not practiced).
Evaluation of Maintenance Factors
Maintenance performance-limiting factors are evaluated
throughout the CPE by data collection, observations, and
questions concerning reliability and service requirements
of pieces of equipment critical to plant performance. If
units are out of service routinely or for extended periods
of time, maintenance practices may be a significant con-
tributing cause to a performance problem. However,
equipment breakdowns are often used as excuses for
performance problems. For example, one operator
blamed excessive turbidity levels from the sedimentation
basin on the periodic breakdown of the primary alum
feeder. However, the backup feeder, while of greater
capacity, could have provided an acceptable alum dose.
The real cause of the poor sedimentation basin perfor-
mance was a lack of understanding by the operator of the
importance of maintaining the chemical dose rate.
18
-------
II is important that maintenance activities be evaluated with
respect to their impact on plant performance and not on the
basis of comparison to the availability of a documented
preventive maintenance program. As such, maintenance
would riot be identified as a performance-limiting factor at a
plant that is exhibiting a high degree of performance but has
no documented routine maintenance system.
Assessment of Applicability of a CCP
Proper interpretation of the CPE findings is necessary to
provide the basis for a recommendation to pursue the
performance improvement phase (see Chapter 3). It is at
this assessment phase that the maximum application of
the evaluator's judgment and experience is required.
The initial step in assessment of CCP applicability is to
determine if improved performance is achievable by
evaluating the capability of major unit processes. A CCP
is recommended if unit processes receive a Type 1 or
Type 2 rating. However, if major unit processes are defi-
cient in capacity, acceptable performance from each
"barrier" may not be achievable, and the focus of fol-
lowup efforts must include addressing public health-re-
lated factors. Also, for Type 3 facilities a more detailed
evaluation of options for modification is warranted. This
concept is shown schematically in Figure 2-7.
Although all performance-limiting factors can theoretically
be eliminated, the ultimate decision to conduct a CCP
may depend on the factors that are identified during the
CPE. An assessment of the list of prioritized factors helps
assure that all factors can realistically be addressed
given the unique set of factors noted. There may be
reasons why a factor cannot be approached in a
straightforward manner. Examples of issues that may not
be feasible to address directly are replacement of key
personnel, increases in rate structures, or training of un-
cooperative administrators to support plant needs. In the
case of recalcitrant administrators who do not take water
quality regulations seriously, regulatory pressure may be
necessary before a decision is made to implement a
CCP.
For plants where a decision is made to implement a
CCP, all performance-limiting factors must be considered
as feasible to correct. These are typically corrected with
adequate "training" of the appropriate personnel. The
training is addressed toward the operational staff for im-
provements in plant process control and maintenance,
toward the plant administrators for improvements in ad-
ministrative policies and budget limitations, and toward
operators and administrators to achieve minor facility
modifications. Training, as used in this context, describes
activities whereby information is provided to facilitate un-
derstanding and implementation of corrective actions.
CPE Report
Results of a CPE are summarized in a brief written report
to provide guidance for facility administrators and
operators and, in some cases, State regulatory person-
nel. It is important that the report be Kept brief so that the
maximum amount of resources is used for the evaluation
rather than preparing an all inclusive report, The report
should present enough information to allow the decision-
making official to initiate efforts toward achieving desired
performance from their facility. It should not provide a list
of specific recommendations for correcting individual per-
formance-limiting factors. Making specific recommenda-
tions often leads to a piecemeal approach to corrective
actions, and the goal of improved performance is not
achieved. For Type 1 and Type 2 plants, the necessity of
comprehensively addressing the combination of factors
identified by the CPE through a CCP should be stressed.
For Type 3 plants, a recommendation for a more detailed
study of anticipated modifications may be warranted. Ap-
pendix E includes a sample CPE report.
CONDUCTING A CPE
A CPE involves the conduct of numerous activities within
a structured framework to determine if significant im-
provements in treatment performance can be achieved
without major capital improvements. A schematic of CPE
activities is shown graphically in Figure .2-8. Initial ac-
tivities are conducted prior to onsite efforts and involve
notifying appropriate utility personnel to ensure that they
will be available. The kickoff meeting, conducted on site,
allows the evaluators to describe onsite activities, lo
coordinate schedules, and to notify personnel of the
materials that will be required. Following the kickoff meet-
ing, a plant tour is conducted by the superintendent or
process control supervisor. During the tour, the
evaluators ask questions regarding the plant and notice
items that may require additional attention during data
collection activities. For example, an evaluator might
make a mental note to investigate more thoroughly the
flow splitting arrangement prior to flocculation basins.
Following the plant tour, data collection activities begin.
Depending on team size, the evaluators split into groups
to facilitate simultaneous collection of the administrative,
design, operations, maintenance, and performance data.
After data are collected, the major unit process evalua-
tion and performance assessment are conducted. Com-
pleting these activities prior to the interviews provides the
evaluators with an understanding of plant unit process
capability and current plant performance, which allows in-
terview questions to be focused on possible factors limit-
ing plant performance. Interviews and special studies are
then conducted which allow additional insight to be
gained regarding actual plant performance and what fac-
tors are contributing to the level of performance ob-
served.
After all information is collected, the evaluation team
meets at a location away from the utility personnel to
review findings. At this meeting, factors limiting perfor-
19
-------
Figure 2-7. CPE/CCP schematic of activities.
Facility
Modifications
Desired Performance Achieved
Abondon
Existing
Facilities and
Design New
Ones
Type 2
Major Unit Processes
Are Margin a!
Type 1
Major Unit Processes
Are Adequate
Type J
Major Unit Processes
Are Inadequate
Major Unit Processes
CPE Evaluation
Implement CCP to
Optimize Evisting Facilities
Before Initiating
Facility Modifications
Implement CCP to
Achieve Desired
Performance
From Existing Facilities
— Evaluate Options For
Facility Modifications
— Address Public Heolth
Related Factors
Plant Administrators or
Regulators Recognize
Need To Evaluate or
Improve Plant Performance
mance of the plant are identified and prioritized. The
prioritized list of factors, performance data, and major
unit process evaluation data are then compiled and
copied for use as handouts during the exit meeting. An
exit meeting is held with appropriate operating and ad-
ministrative personnel where all evaluation findings are
presented.
Offsite activities include assessing the applicability of a
followup CCP arid completing the written report. A more
detailed discussion of each of these activities follows.
Personnel Capabilities
A CPE is typically conducted over a 3- to 5-day period by
a team composed of a minimum of two personnel. The
team approach allows a plant to be evaluated in a
reasonable timeframe and for personnel to share impres-
sions. Shared impressions are especially important when
identifying and prioritizing performance-limiting factors
and in assessing major unit process capability since
these efforts require a significant amount of judgment.
Persons responsible for conducting CPEs should have a
knowledge of water treatment, including the following
areas:
• Regulatory requirements
• Hydraulic principles
• Process control
• Operator training
• Coagulation chemistry
• Safety
• Process design
• Maintenance
• Sampling
• Management
• Laboratory testing
• Utility budgeting
• Water rate structures
• Interview skills
• "People" skills
20
-------
Figure 2-8. Schematic of CPE activities.
Location
Off-Site
Data Collection Activities
On —Site
Off-Site
CPE Report
Plant Tour
Administration
Data
Performance
Data
Design
Data
Operations
Data
Maintenance
Data
Exit
Meeting
Conduct Specia
Studies
Kick—off
Meeting
Conduct
Interviews
Initial
Activities
Identify and
Prioritize
Factors
Evaluate
Major Unit
Processes
Conduct
Performance
Assessment
Assess
Applicability
of CCP
21
-------
Regulatory agency personnel with experience in evaluat-
ing water treatment facilities and consulting engineers
who routinely work with plant evaluation, design, and
startup represent the types of personnel with adequate
backgrounds to conduct CPEs.
Initial Activities
To determine the magnitude of the field work required
and to make the onsite activities most productive, specific
initial information should be gathered. This information in-
cludes basic data on the plant size and staffing and sour-
ces for required information needed for the evaluation. If
a person associated directly with the plant is the
evaluator conducting the CPE, some of the steps may
not be necessary.
Identify Key People
It is necessary to have key people available during the
conduct of the CPE. Therefore, these people should be
identified and their availability determined. The plant su-
perintendent, manager, or other person in charge of the
water treatment facility must be available. If different per-
sons are responsible for plant maintenance and process
control, their presence should also be required. These
persons should be available throughout the field ac-
tivities.
A person knowledgeable about details of the utility
budget must also be available. A 1- to 2-hour meeting
with this person will typically be required during the field
work to assess the financial aspects of the utility. In many
small communities, this person is most often the city
clerk; in small water districts it may be the chairman of
the board or a part-time clerk. In larger communities, the
finance director, utilities director, or plant superintendent
can usually provide the best information.
Availability of key administrative personnel is required. In
many small communities or water districts, an operator or
plant superintendent may report directly to the mayor or
board chairman or to the elected administrative body (city
council or district board). In larger communities, the key
administrative person is often the director of public
works/utilities, city manager, or other nonelected ad-
ministrator. In all cases the administrator(s) as well as
representative elected officials who have the authority to
effect a change in policy or budget for the plant should be
available.
If a consulting engineer is currently involved with the
plant, that individual should be informed of the CPE and
provided with a copy of the report. Normally, the consult-
ing engineer will not be directly involved in the conduct of
the CPE. An exception may occur if there is an area of
the evaluation that could be supplemented by the exper-
tise available through the consultant.
Scheduling
When initiating a CPE, a letter should be sent to the
utility describing the schedule of activities that will take
place and outlining the commitment required of plant
and administrative staff. A sample letter is presented in
Appendix D. Interviews of personnel associated with
the plant are a key component of conducting a CPE.
As such, the major criterion for scheduling the time for
a CPE should be local personnel availability. If the
CPE is conducted by personnel not associated with a
regulatory agency, it may be beneficial to inform State
and Federal regulatory personnel of the CPE schedule.
Responsibility for this task should be clearly identified
by the evaluator and local personnel during the
scheduling of activities.
Data Collection
Onsite CPE activities are largely devoted to collection
and evaluation of data. As a courtesy to the facility owner
and to promote efficient data collection, the field work is
initiated with a kickoff meeting. This activity is followed by
a plant tour and a period of time where detailed data on
the plant are gathered and analyzed.
Kickoff Meeting
A short (less than 30 minutes) meeting between key plant
operating and administrative staff and the evaluators
should be held to initiate the field work. The major pur-
poses of this meeting are to present the objectives of the
CPE effort, to coordinate and establish the schedule, and
to initiate the administrative evaluation activities. Each of
the specific activities that will be conducted during the on-
site effort should be described. Meeting times for inter-
views with nonplant and plant personnel should be
scheduled. A signup sheet (see Appendix C) may be
used to record attendees as a means of assisting with
recall of names.
Information and resource requirements should be estab-
lished. Specific items that are required and may not be
readily available are budget information to provide a com-
plete overview of costs associated with water treatment;
a water rate schedule including tapping fees, historical
monitoring data for a 1-year period; plant O&M manuals,
if available; and any facility drawings and specifications
or other engineering studies available for the existing
facilities.
Administrative factors that may affect plant perfor-
mance should be noted during this meeting, such as
the priority of high quality finished water, familiarity
with plant needs, communication between administra-
tion and plant staff, and policies on plant funding.
These initial perceptions often prove valuable when
formally evaluating administrative factors later in the
CPE effort.
22
-------
Plant Tour
A plant tour should follow the kickoff meeting. The objec-
tives of the tour are to familiarize the evaluator with the
physical plant, make a preliminary assessment of opera-
tional flexibility of the existing processes and chemical
feed systems, and provide an initial basis for discussions
on performance, process control, and maintenance. A
walk-through tour following the flow from the raw water
source through the plant to the clearwell is suggested. It
is then appropriate to tour backwash and sludge treat-
ment and disposal facilities, followed by the support
facilities, such as the laboratory and maintenance areas.
The evaluator should note the sampling points and
chemical feed locations throughout the plant.
During the conduct of a plant tour, the evaluator must be
sensitive to the plant personnel conducting the tour.
Questions that challenge current operational practices or
that put plant personnel on the defensive should be
avoided. The evaluator should try to maintain an informa-
tion gathering posture at all times. It is not appropriate to
recommend changes in facilities or operational practices
during the plant tour although the evaluator will often be
asked for an opinion. A desired response is to state that
observations will be presented at the conclusion of the
onsite activities and after additional information is col-
lected and analyzed. Most of the questions asked on the
plant tour will be asked again during formal data collec-
tion activities. The staff should be informed that this
repetitiveness will occur. The plant tour also provides an
excellent opportunity for the evaluator to observe intan-
gible items that may contribute to the identification of fac-
tors limiting performance (i.e., operator knowledge of the
plant operation and facilities, relationship of process con-
trol testing to process adjustments, etc.). Suggestions to
help the evaluator meet the objectives of the plant tour
are provided in the following sections.
Pretreatment
Pretreatment facilities consist of raw water intake struc-
tures, screening equipment, raw water pumps,
presedimentation basins, and flow measurement equip-
ment.
Intake structures and screening equipment can have a
direct impact on plant performance. For example, if the
intake configuration is such that screens become clogged
with river moss or the intake becomes clogged with silt,
consistent supply of water may be a problem. While at
the raw water source, questions should be asked regard-
ing variability of the raw water quality, potential upstream
pollutant sources, seasonal problems with taste and
odors, raw water quantity limitations, and algae blooms.
Raw water pumping should be evaluated regarding the
ability to provide a consistent water supply and with
respect to how many pumps are operated at a time. Fre-
quent changing of high volume constant speed pumps
can cause significant hydraulic surges to downstream
unit processes, such as filters, degrading plant perfor-
mance. In addition, operational practices as they relate to
peak flow rates, peak daily water production, and plant
operating hours should be discussed to assist in defining
the peak instantaneous operating flow rate.
Presedimentation facilities are usually only found at water
treatment plants where raw water turbidities exceed
several hundred NTUs. If plants are equipped with
presedimentation capability, basin inlet and outlet con-
figurations should be noted and the ability to feed
coagulant chemicals should be evaluated. Typically, most
presedimentation configurations lower turbidities enough
to allow conventional water treatment plants to perform
adequately. If presedimentation facilities do not exist, the
evaluator must assess the capability of existing water
treatment unit processes to remove peak raw water tur-
bidities.
Flow measurement facilities are important to accurately
establish chemical feed rates, wash water rates, and unit
process loadings. The plant tour should be used to ob-
serve the location of flow measurement equipment and to
ask questions regarding various plant flows. Questions
should be asked concerning maintenance and calibration
of flow measurement devices.
Mixing/Flocculation/Sedimentation
Rapid mixing is utilized to provide a complete instan-
taneous mix of coagulant chemicals to the water. The
coagulants neutralize the negative charges on the col-
loidal particles allowing them to agglomerate into larger
particles during the gentle mixing of flocculation. These
heavier particles are then removed by settling in the
quiescent area of the sedimentation basin. These
facilities provide the primary barrier to public health in the
plant and, if properly designed and operated, reduce the
particulate load to the filters, allowing them to "polish" the
water. During the tour, observations should be made to
determine if the mixing, flocculation, and sedimentation
unit processes are designed and operated to achieve this
goal. The evaluator should also observe flow splitting
facilities and determine if parallel basins are receiving
equal flow distribution.
Rapid mix facilities should be observed to determine if
adequate mixing of chemicals is occurring. The operator
should be asked what coagulant aids are being added
and what process controls are employed to determine
their dosage. Observations should be made as to the
types of chemicals that are being added together in the
mixing process. For example, the addition of alum and
lime at the same location may be counter productive if no
consideration is given to maintaining the optimum pH for
alum coagulation. If coagulant chemicals are added
without mixing, observations should be made as to pos-
sible alternate feed locations, such as prior to valves,
23
-------
orifice plates, or hydraulic jumps, where acceptable
mixing might be achieved.
When touring flocculation facilities, the evaluator should
note inlet and outlet conditions, number of stages, and
the availability of variable energy input. Flocculation
facilities should be baffled 1o provide even distribution of
flow across the basin and to prevent velocity currents
from disrupting settling conditions in adjacent sedimenta-
tion basins. If multiple stages are not available, the
capability to baffle a basin to create additional staging
should be observed. The ability to feed flocculation aids
to the gentle mixing portion of the basin should be noted.
The operator should be asked how often flocculation
energy levels are adjusted or if a special study was con-
ducted to determine the existing levels. In the case of
hydraulic flocculation, the number of stages, the tur-
bulence of the water, and the condition of the floe should
be noted to determine if the unit process appears to be
producing an acceptable floe.
Sedimentation basin characteristics that should be ob-
served during the tour are visual indicators of perfor-
mance and physical characteristics such as configuration
and depth. Performance observations include clarity of
settled water, size and appearance of floe, and presence
of flow or density currents. The general configuration, in-
cluding shape, inlet conditions, outlet conditions, and
availability of a sludge removal mechanism should be ob-
served. The operator should be asked what process con-
trol measures are utilized to optimize sedimentation
including sludge removal.
Filtration
Filters are utilized to remove the particles that are too
small to be removed in sedimentation basins by gravity
settling. The number and configuration of filters should be
noted, including the type of filter media. The filter rate
control equipment should be observed and discussed to
ensure that it regulates filter flow in an even, consistent
manner without rapid fluctuations. The flow patterns onto
each filter should be noted to see if there is an indication
of uneven flow to individual filters. Backwash equipment,
including pumps and air compressors, should be noted.
The availability of backup backwash pumping is desirable
to avoid interruptions in treatment if a breakdown occurs.
The operator should be asked how frequently filters are
backwashed and what process control procedures are
used to determine when a filter should be washed.
Preferably turbidity, rather than headloss, should be the
parameter utilized since it relates to water quality. The
operator's response to these inquiries helps to
demonstrate his or her understanding and priorities con-
cerning water quality. The operators should also be ques-
tioned concerning the backwash procedure and if all
operators follow the same technique.
Disinfection
The evaluator should tour disinfection facilities to become
familiar with the equipment feed points, and type of con-
tact facilities. Special attention should be given to the
configuration and baffling of clearwells and finished water
reservoirs that provide contact time for final disinfection.
Observation of in-line contact time availability should be
made by noting the proximity of the "first user" to the
water treatment plant.
The availability of backup disinfection equipment should
be observed to assess capability of providing an uninter-
rupted application of disinfectant. The addition of a disin-
fectant prior to filtration, either as an oxidizing agent or
disinfectant, should also be noted. The capability to auto-
matically control the disinfection systems by flow pacing
should be determined.
Backwash Water and Sludge Treatment and Disposal
During the tour, the evaluator should become familiar
with the facililies available to handle filler backwash
water and sedimentation basin sludge. If backwash water
and sludge are discharged to the storm sewer system or
a waterway, questions should be asked to determine if
the discharge is permitted and if permit requirements are
being complied with.
The location of any recycle streams should be identified
during the tour. Recycle of backwash water should be as-
sessed relative to the feasibility of returning a potentially
high concentration of cysts to the plant raw water stream.
Cysts are primarily removed by the filters so that the
recycle of backwash water in a plant where the raw water
has a high potential for substantial numbers of cysts may
compound the health risk, depending on washwater treat-
ment.
Laboratory
The laboratory facilities should be included as part of the
plant tour. Performance monitoring, process control test-
ing, and quality control procedures should be discussed
with laboratory personnel. It is especially important to
determine if turbidity measurements represent actual
plant performance. Available analytical capability should
also be noted.
Maintenance
Maintenance facilities should be included as part of the
plant tour. Tools, spare parts availability, storage, filing
systems for equipment catalogs, general plant ap-
pearance, and condition of equipment should be ob-
served. Questions on the preventive maintenance
program, including methods of initiating work (e.g., work
orders), are appropriate.
24
-------
Detailed Data Gathering
Following the plant tour, formalized data collection proce-
dures are initiated. Information is collected through con-
ducting interviews with plant and administrative staff;
reviewing plant records, drawings, specifications, process
control data sheets, etc.; and conducting field evalua-
tions.
Plant Records
A variety of plant records including budgets, drawings
and specifications, State monitoring reports, operational
logs, O&M manuals, and manufacturers' literature are re-
quired for the formal data collection efforts. The forms in
Appendix C have proven to be valuable in compiling in-
formation from these multiple sources in a consistent
manner. Categories covered by these forms are listed
below:
• Kickoff Meeting
• Administration Data
• Design Data
• Operations Data
• Maintenance Data
• Performance Data
• Interview Data
• Exit Meeting
When collecting information, the evaluator should be
aware that the data are to be used to evaluate the perfor-
mance capability of the existing facilities. The evaluator
should continuously be asking, "How does this informa-
tion affect plant performance?" If the area of inquiry is
directly related to plant performance, such as filter design
or an indication of an administrative policy to cut costs by
reducing chemical addition, the evaluator should spend
sufficient time to fully develop the perceived effect of the
information on plant performance.
Field Evaluations
Field evaluations are an important means of identifying
performance problems. Typically, field evaluations should
be conducted to verify accuracy of monitoring and flow
records, chemical dosages, record drawings, filter in-
tegrity, and backwash capability.
Performance monitoring records can be verified by
measuring turbidities from an individual filter and the
clearwell. It is important that the evaluator provide
properly calibrated turbidimeters to support this field ef-
fort. A recording on-line turbidimeter or an instrument that
allows individual analysis of grab samples can be used.
Treated water quality obtained from the field evaluation
can be compared with the recorded data to make a deter-
mination if performance monitoring records accurately
represent treated water quality. Differences in actual ver-
sus recorded finished water quality can be caused by
sampling location or sampling time. The evaluator instru-
ment can also be used to assess the plant's turbidimeter
and calibration techniques.
The accuracy of flow records can be verified by assessing
the calibration of flow measurement equipment. This is
often difficult because the types of meters utilized (e.g.,
propeller, venturi, orifice plates, magnetic, etc.) require a
basin to be filled or drawn down to accurately check the
metering equipment. If accuracy of metering equipment is
impossible to field verify, the frequency of calibration of the
equipment by the plant staff or outside instrumentation tech-
nicians can be evaluated. If flow metering equipment is
being routinely (e.g., quarterly or semiannually) calibrated,
flow records typically can be assumed to be accurate.
Dosages of primary coagulant chemicals should be
verified. Feed rates from dry feeders can be checked by
collecting a sample for a specified time and weighing the
accumulated chemical. Similarly, liquid feeders can be
checked by collecting a sample in a graduated cylinder
for a specified time. In both cases, the Ib/min or mL/min
of chemical should be converted to mg/L and compared
with the reported dosage. During this evaluation, the
operating staff should be asked how they conduct chemi-
cal feed calculations, prepare polymer dilutions, and
make chemical feeder settings.
The integrity of the filter media, support gravels, and un-
derdrain system should be evaluated. This requires that
the filter be drained and that the evaluator inspect the
media. The filter should be investigated for surface crack-
ing, proper media depth, and the occurrence of sand
(dual media filter) or gravel on the top of the filter. The fil-
ter should also be probed with a steel rod to check for
displacement of the support gravels. Variations in depth
of over 2 inches would signify a problem. A more detailed
study of the filter would then be indicated, which is
beyond the scope of a CPE.
Filter backwash capability should be field verified by as-
sessing either the backwash rise rate or bed expansion.
Rise rate is determined by liming the rise of water for a
specific rise time and depth. For example, a filter having
a surface area of 13.9 m2 (150 ft2) would have a back-
wash rate of 1,173 m3/m2/d (20 gpm/ft2) if the rise rate
was 27.2 cm (10.7 inches) in 20 seconds. This technique
is not suitable for filters where the peak backwash rate is
not reached until the wastewater is passing over the
troughs.
Bed expansion is determined by measuring the distance
from the top of the unexpanded media to a reference
point (e.g., top of filter wall) and from the top of the ex-
panded media to the same reference point. The dif-
ference divided by the total depth of media multiplied
times 100 gives the percent bed expansion. A proper
25
-------
wash rate should expand the filter media a minimum of
20 to 25 percent (1).
Record drawings may have to be field verified by
measuring basin dimensions with a tape measure if there
is doubt as to their accuracy. If no drawings are available,
all basin dimensions will have to be measured.
Evaluation of Major Unit Processes
An evaluation of the plant's major unit processes is con-
ducted to determine the performance potential of existing
facilities at peak instantaneous operating flow. This is ac-
complished by developing a performance potential graph and
rating the major unit processes as Type 1, 2, or 3, as dis-
cussed in "CPE Methodology" on p. 5.
It is important that the major unit process evaluation be
conducted early in the onsite activities since this assess-
ment provides the evaluator with the knowledge of the
plant's treatment capability. If a poorly performing plant's
major unit processes are determined to be Type 1 or 2,
then typically factors in the areas of administration,
operation, or maintenance are primarily contributing to
the performance problems. The completed major unit
process assessment allows the evaluator to focus later
interviews and data gathering to identify those perfor-
mance-limiting factors.
Performance Assessment
An assessment of the plant's performance is made by
evaluating existing recorded data and by conducting on-
site evaluations to determine if unit process and total
plant performance have been optimized. Typically, the
previous 12 months of existing process control data are
evaluated and graphs are developed to assess perfor-
mance of the plant. Other periods of process control data
can be evaluated if they are more representative of plant
operating conditions. Field evaluations are also con-
ducted to determine if existing plant records accurately
reflect actual plant treated water quality. A detailed dis-
cussion of the methods utilized in the performance as-
sessment are presented in "Conducting Performance
Assessment" on p. 10.
Interviews
It is beneficial to complete filling out the data collection
forms and to complete the major unit process evaluation
and performance assessment before initiating the formal-
ized interviews, since this background information allows
the evaluator to better focus interview questions. Inter-
views should be conducted with all of the plant staff, in-
cluding the superintendent and foremen, and with key
administrative personnel. Key administrators typically in-
clude the mayor, a councilman or board member from the
water committee, and the utility director. The interviews
should be conducted privately with each individual. Ap-
proximately 30 minutes should be allowed for each inter-
view.
Interviews are conducted to clarify information obtained
from plant records and to ascertain differences between
real or perceived problems. Intangible items such as
communications, administrative support, morale, and
work attitudes are also assessed during the interview
process. Administrative and plant staff are both inter-
viewed in order to obtain both sides of the story. The per-
formance focus of the CPE process must be maintained
in the interviews. For example, an adamantly stated con-
cern regarding supervision or communication is only of
significance if it can be directly related to plant perfor-
mance.
Evaluation of Performance-Limiting Factors
After all data has been gathered, the major unit process
evaluation has been completed, plant performance has
been assessed, and formal interviews have been com-
pleted, identification and prioritization of performance-
limiting factors should be conducted. The identification of
factors should be completed at a location that allows
open and objective discussions to occur (e.g., away from
plant staff). Prior to the discussion, a debriefing session
should be held that allows the evaluators to discuss per-
tinent findings from their respective efforts. This step is
especially important if more than two evaluators are in-
volved in the CPE because, with larger evaluation teams,
not all members can be exposed to every aspect of the
comprehensive evaluation. All data compiled during the
evaluations should be readily available to support the fac-
tor identification efforts.
The checklist of performance-limiting factors presented in
Appendix B, as well as the factor definitions, provides the
structure for an organized review of problems in the sub-
ject plant. The intent is to identify, as clearly as possible,
the factors that most accurately describe the causes of
limited performance. Often a great deal of discussion is
generated in this phase of the CPE effort. Several hours
should be allocated to complete this step and all opinions
and perceptions should be solicited. It is particularly im-
portant to maintain the performance focus during the ac-
tivity in order to avoid identifying factors that do not have
this emphasis.
Each factor identified as limiting performance should be
assigned an "A," "B," or "C" rating. Further prioritization is
accomplished by completing the Summary Sheet
presented in Appendix B. Only those factors receiving
either an "A" or "B" rating are prioritized on this sheet.
Additional guidance for identifying and prioritizing perfor-
mance-limiting factors is provided in "Identification and
Prioritization of Performance-Limiting Factors" on p. 14,
26
-------
Exit Meeting
Once the evaluation team has completed the field work
for the CPE, an exit meeting should be held with the plant
administrators and staff. A presentation of preliminary
CPE results should include brief descriptions of the fol-
lowing:
• Plant performance assessment
• Evaluation of major unit processes
• Prioritized performance-limiting factors
• Plant performance potential
Handouts, typically handwritten, summarizing these
topics can be utilized to assist in the exit meeting presen-
tation. Handouts typically utilized to present performance
assessment findings are time versus turbidity plots (1
year of data) and percentile plots for raw, settled, and
finished water, and results of field evaluations such as
turbidity profiles following a filter backwash. The perfor-
mance potential graph and factor summary sheet can be
utilized to present information regarding the major unit
process evaluation and performance-limiting factors,
respectively.
If the CPE reveals that the treatment plant performance
represents a significant health impact, this should be
carefully explained to the utility staff. Regulatory person-
nel conducting such a CPE should determine if ad-
ministrative or regulatory action should be implemented.
If a utility is operating within applicable turbidity regula-
tions, but not optimizing treated water quality, a presenta-
tion can be made as to the potential health advantage of
setting more aggressive goals such as a finished water
turbidity of less than 0.1 NTU. A brief presentation on the
function of each water treatment unit process and the ef-
fort required to produce acceptable finished water quality
can also be made to enhance water treatment under-
standing for the administrators.
It is important to present all findings al the exit meeting
with local officials. This approach eliminates surprises
when the CPE report is received and lays the foundation
for the approach necessary for any followup activities. In
situations where administrative or staff factors are difficult
to present, the evaluator must be sensitive and use com-
munication skills to successfully convey the results.
Throughout the discussions, the evaluator must remem-
ber that the purpose of the CPE is to identify and
describe facts to be used to improve the current situation,
not to place blame for any past or current problems.
It is emphasized that findings, and not recommendations,
be presented at the exit meeting. The CPE, while com-
prehensive, is conducted over a short time and is not a
detailed engineering design study. Recommendations
made without appropriate followup could confuse
operators and administrators, and lead to inappropriate
or incorrect actions on the part of the utility staff (e.g., im-
proper technical guidance). For example, a recommenda-
tion to set coagulant dosages at a specific level could be
followed literally to the extent that the next time the
evaluator is at the plant, coagulant dosages may still be
the same as that recommended even though time and
highly variable raw water conditions have passed.
It should also be made clear at the exit meeting that other
factors are likely to surface during the conduct of any fol-
lowup activities. These factors will also have to be ad-
dressed to achieve the desired performance. This
understanding of the short-term CPE evaluation
capabilities is often missed by local and regulatory offi-
cials, and efforts may be developed to address only the
items prioritized during the CPE. The evaluator should
stress that a commitment must be made to achieve the
desired improved performance, not to addressing a
"laundry list" of currently identified problems. An ideal
conclusion for an exit meeting is that the facility owners
fully recognize their responsibility to provide a high
quality finished water and that, armed with the findings
from the CPE, they are enthusiastic to pursue achieve-
ment of this goal.
CPE Report
At the conclusion of the field activities, a CPE report is
prepared. The objective of a CPE report is to summarize
findings and conclusions. Eight to twelve typed pages are
generally sufficient for the text of the report. A sample
report is presented in Appendix E. Typical contents are:
• Introduction
• Facility Information
• Major Unit Process Evaluation
• Performance Assessment
• Performance-Limiting Factors
• Projected Impact of a CCP
At a minimum, the CPE report should be distributed to
plant administrators and key plant personnel. Further dis-
tribution of the report (e.g., to the design engineer)
depends on the circumstances of the CPE, but should be
done at the direction or with the awareness of local ad-
ministrators.
Case Study
An 11,355 m3/d (3.0 MGD) conventional plant consisting
of an upflow solids contact sedimentation basin and dual
media filtration serves a residential community with a
population of 3,300. The State regulatory agency iden-
tified in their review of routine monitoring reports that
finished water turbidities were periodically and slightly
above the 1.0 NTU limit. The State notified the com-
munity that they were going to conduct a CPE to deter-
27
-------
mine if there was a performance problem and, if so, to
determine the causes of the poor performance.
Facility Information
A flow schematic of the plant is presented in Figure 2-9.
The following data were compiled from the completed
data collection forms, as presented in Appendix C. The
plant was being operated at 11,355 m3/d (3.0 MGD) (one
raw water pump) for the length of time required to fill the
storage reservoir, which was approximately 5 hours per
day during winter months and 10 hours per day during
summer months.
Filtration:
Design Flaw:
11,355 m /d (3.0 MGD)
Peak Instantaneous Operating Flow:
Average Daily Flow:
Peak Daily Flow:
Raw Water Intake:
Flow Measurement:
Sedimentation:
11,355 m /d (3.0 MGD)
2,271 m3/d (0.6 MGD)
4,542 m3/d (1.2 MGD)
2 vertical turbine pumps at 11,355 m3/d
(2,100 gpm each)
Propeller meter with strip chart recorder
Number: 1
Type: Solids contact
Settling Area: 100 m2 (1,075 ft2)
Depth: 4 m (13 ft) with 45°
tube settlers
Number:
Type:
Dimensions:
Area:
Dual media
3.7 m x 3.7 m
(12 ft x 12 ft)
13.4 m2 (144 ft2)
per filter
Clearwell
530 m (140,000 gallon) baffled basin
Chemical Feed Facilities:
Treated Water Pumps:
Two dry alum feeders each rated at
5 7 to 1,134 kg/d (125 to 2,500 Ib/d)
Two polymer feed systems each with
a 189 liter (50 gallon) dilution tank
and a 63 to 347 mLVmin
(1.0 to 5.5 gal/hr) pump
Two gas chlorination systems (post-
chlorination only), each rated at
57 kg/d (125 Ib/d)
Two vertical turbine pumps at
11,355 m3/d (2,100 gpm) each
Major Unit Process Evaluation
A performance potential graph (Figure 2-10) was
prepared to assess the capability of the facility's major
unit processes. The calculations that were conducted to
complete the graph and major unit process evaluation
are shown below.
Figure 2-9. Flow schematic of plant in CPE case study.
RAW WATER r /
PUMPS
MS
SLUDGE
BEDS
INTAKE STRUCTURE
OVERFLOW
TO
RIVER
i
BACKWASH
PUMPS
BACKWASH
POND
ALUM
POLYMER
DUAL MEDIA
FILTERS
FLOW
METER
UPFLOW SOLIDS
CONTACT BASIN
CLEARWELL
HIGH SERVICE
PUMPS
TO
DISTRIBUTION
SYSTEM
28
-------
t
Sedimentation Basin
SOR at 11,355 m3/d = (11,355 m3/d) +
100 m2= 113.6 m3/m2/d
SOR at 3.0 MGD = (3.0 MGD x 694.4 gpm/MGD)-f-
1075 ft3
= 1.94 gpm/ft2
Rate at 59 m3/m2/d or 1.0 gpm/ft2 (from Table 2-1)
Rated capacity = 1.0 gpm/ft x 1,075 ft2
= 1,075 gpm or 1.55 MGD or
Rated capacity - 59 m3/m2/d x 100 m2
- 5,880 m3/d
Filtration
Area = 4 x 3.7 m x 3.7 m =. 54 m2
Area - 4 x 12 ft x 12 ft-576 ft2
Loading rate at 3.0 MGD
= (3.0 MGD x 694.4 gpm/MGD)+
576 ft2
= 3.6 gpm/ft2 or
Loading rate at 11,355 m3/d
= (11,355 m3/d) + 54 m2
= 210 m3/m2/d
Rate at 117 m3/m2/d (2.0 gpm/ft2) rather than 235 m3/m2/d (4.0
gpm/ft2) because of observed air binding a! higher rates (from
Table 2-1).
Rated Capacity = 2.0 gpm/ft2 x 576 ft2
- 1,152 gpm or 1.66 MGD or
Rated Capacity -117 m /m2/d x 54 m2
= 6,318 m3/d
Disinfection
Estimate required log reduction of Giardia cysts based on
surface water quality.
Use 4.0 log reduction because river supply has wastewater
discharges upstream.
Project log reduction credit for existing plant.
Allow 2.5 log reduction of Giardia cysts for conventional
plant (see Table 2-2).
Therefore, a 1.5 log reduction (4,0 - 2,5) is required in final
disinfection.
Select CT value (see Appendix A).
Finished water pH = 7.5
Minimum temperature - 0.5 °C
Maximum chlorine residual acceptable
= 2.5 mg/L
Select CT = 150 mg/L - min. from Appendix A.
Calculate effective volume for contact.
Clearwell is only available volume for contact because
first tap is adjacent to plant.
Backwash lowers clearwell depth to one-half of full depth.
Evaluate basin at minimum depth; therefore, use half of
140,000 gallon basin.
Use factor of 0.9 based on serpentine baffling throughout
basin (see Table 2-3) and factor of 0.5 (e.g., 1/2) to
account for minimum water depth.
Effective basin volume = 0.9 x 0.5 x 140,000 gallons
= 63,000 gallons
= 238 m3
Calculate required detention time.
Required HDT - 150 mg/L-min+ 2.5 mg/L
= 60 min
Calculate required rate of flow to achieve detention time of 60
minutes.
Flow Rate = 63,000 gallons = 1 050 or 1 5 MGD
60 min
_ 238 m3 _ 3 gy m3/mjn or 5 712 m3/d
60 min
As shown in Figure 2-10, the limiting unit process is disin-
fection, which was rated at 1.5 MGD (5,700 m3/d). This is
less than 90 percent of the actual peak instantaneous
operating flow rate of 3.0 MGD (11,355 m3/d), which indi-
cates a Type 3 rating. The type ratings for all unit proces-
ses are shown in Table 2-5, As shown, all unit processes
were rated Type 3 because they were assessed to have
a capacity less than 90 percent of the actual peak instan-
taneous operating flow of 3.0 MGD (11,355 m3/d). Fur-
ther evaluation of flow records and operating times
revealed that the plant could be easily operated for
longer periods of time each day and that the peak flow
could be kept at 1.5 MGD (5,700 m3/d) or less, which
would result in all major unit processes achieving 100
percent of the established peak instantaneous operating
flow. Therefore, the maximum flow (peak instantaneous
operating flow) that the plant would successfully operate
at was established at 1.5 MGD (5,700 m3/d), resulting in
a Type 1 rating for all unit processes.
Table 2-5. Rating of the Unit Processes and Overall Plant
for the Case Study
Unit Process
Rating
3.0 MGD"
1.5 MGD
(473 mJ/hr)
(236 m3/hr)
Sedimentation
Type 3
Type 1
Filtration
Type 3
Type 1
Disinfection
Type 3
Type 1
'Design flow.
Performance Assessment
The performance assessment conducted using plant
records indicated that the finished water turbidity rarely
exceeded 1.0 NTU but that the plant would not achieve
the proposed new SWTR requirement that 95 percent of
the samples collected each month have a turbidity less
than 0.5 NTU. The settled water turbidity averaged about
10 NTU. Special studies conducted of the filter effluent
turbidity revealed a turbidity spike of 3.5 NTU when the
plant was started in the morning with dirty filters and of
4.8 following a backwash. The turbidities in both cases
dropped to about 0.8 NTU following an hour of operation.
Performance-Limiting Factors
The following performance-limiting factors were identified
during the CPE and were given ratings of "A" or "B". Fur-
ther prioritization of these factors was also conducted, as
indicated by the number assigned to each factor.
29
-------
A
Operator Application of Concepts and Testing to
Process Control - Operation (A). The plant operators
had established no process control program to make
decisions regarding plant flow rate, coagulant dose,
and filter operation. Coagulant dosages were ap-
proximately 200 percent higher than desired and no
jar tests or other means were used to determine ap-
propriate dosages. Filters were started dirty on a
routine basis and the plant was operated at maxi-
mum capacity when a much lower rate was possible.
Filter effluent and clearwell turbidities were often
above 1 NTU, but samples were collected at the
clearwell immediately after plant startup and thus the
excursions above 1.0 NTU were not evident in plant
records. This practice showed little awareness of the
importance of producing high quality treated water on
a continuous basis.
Process Control Testing - Operation (A). The only
process control testing that was conducted was tur-
bidity on daily grab samples of raw water and treated
water from the clearwell and chlorine residual on
treated water after the high service pumps. No
process control testing was done to control the reac-
tor clarifier, coagulant dosages, or filtration. As such,
there was limited information available to make
process control decisions.
3. Plant Coverage - Administration (A). Plant operators
were only allowed enough time to be at the plant ap-
proximately 1 hour each day. This allowed a periodic
check of equipment; however, frequently raw water
quality would vary and not be noticed for up to 24
hours, resulting in periods of poor treated water
quality. On occasion, the alum feed line would plug
and go unnoticed, resulting in periods of poor treated
water quality. The operators were expected to con-
duct other activities, such as monitoring the city
swimming pool, assisting wastewater treatment plant
operators, and assisting street maintenance crews
during summer months.
4. Sedimentation - Design (B). The sedimentation basin
was not capable of removing suspended particles at
flows above 3.0 MGD (473 m3/hr). Reducing the flow
would allow the basin to perform adequately during
most periods of the year, but the basin could limit
plant performance when raw water turbidities ex-
ceeded 500 NTU periodically during spring runoff.
5. Filtration - Design (B). The filters were limited by
severe air binding during winter months that in-
Figure 2-10. Performance potential graph for CPE case study.
UNIT PROCESS
0.5
1.0
1.5
2.0
2.5
3.0
SOUDS CONTACT*1'
SEDIMENTATION
SOR (gpm/ff)
filtration'2'
RATE (gpm/ff)
DISINFECTION
HOT (MIN)
(3)
RATED
CAPACITY
1.55 mgd
1.66 mgd
1.5 mgd
Peak Dally
Flow = 1.2 mgd
Established
Peak Inst. Operating
Flow = 1.5 mgd
Actual Peak
Inst. Operating
Flow = 3.0 mgd
Comments:
1. Rated at 1.0 gpm/ft!SOR with tube settlers
2. Rated at 2.0 gpm/ft *- dual media; observed air binding problem at higher rates.
3. Based on 4.0 log total log reduction, 2.5 log In plant,
1.5 log by post-dlslnfectlon; CT=150 with 2.5 mg/L free residual, pH 7.5,
temp. = 0.5° C, 90 percent useable clearwell volume for contact and minimum
depth (e.g., 50% of maximum depth).
30
-------
creased the frequency of backwash. The air binding
problem should be relieved by reducing the hydraulic
loading on the filters; however, periodically air bind-
ing may limit plant performance.
6, Disinfection - Design (B). Operation of the plant at
maximum flow rate will not allow sufficient contact
time for disinfection. However, operation of the plant
at or below 1.5 MGD (236 m3/hr) should allow disin-
fection in compliance with the proposed SWTR
regulations to be achieved.
7. Process Controllability/Flexibility - Design (B). The fil-
ter rate controllers were malfunctioning, causing peri-
odic increases in filtered water turbidity. The plant
had no capability of feeding a filter aid.
Assessing Applicability of a CCP
The most serious of the performance-limiting factors
identified were process control oriented. The evaluation
of major unit processes resulted in a Type 3 rating at the
present peak instantaneous operating flow. However, it
was determined that the rating could be upgraded to
Type 1 if the plant peak instantaneous operating flow rate
could be reduced by operating for longer periods of time
each day. This adjustment will require addressing the
plant coverage factor by convincing administrators to
allow operators to spend additional time at the treatment
facility. If plant flow can be reduced and operator
coverage increased, it appears that the utility would be
able to achieve improved performance through im-
plementation of a followup CCP. This recommendation
should be made to the city council. Documentation of im-
proved performance may be difficult because existing
monitoring data do not reflect true past performance.
However, improvement in the turbidity spike after dirty fil-
ter startup and backwashing should be able to be docu-
mented. Settled water turbidity should also be reduced to
the 1 to 2 NTU range from the present 10 NTU, thus en-
hancing the treatment barrier this unit provides.
CPE Results
The success of conducting CPE activities can be
measured by plant administrators selecting an approach
and implementing activities to achieve the required per-
formance from their water treatment facility, if definite fol-
lowup activities are not initialed within a reasonable
timeframe, the objectives of conducting a CPE have not
been achieved. Ideally, followup activities must com-
prehensively address the combination of factors identified
(e.g., implement a CCP) and should not be implemented
in a piecemeal approach. In the previous example, plant
administrators decided to hire an operations consultant to
implement a CCP. The CCP addressed the identified fac-
tors and resulted in the existing plant achieving SWTR
requirements without major capital improvements.
REFERENCES
1. Water Treatment Plant Design. 1990. American
Society of Civil Engineers and American Water
Works Association, McGraw-Hill, 2nd ed.
2. Water Treatment Principles and Design. 1985.
James M. Montgomery Consulting Engineers, Inc.,
John Wiley & Sons, Inc.
3. Sanks, R.L., ed. 1978. Water Treatment Plant Design
for the Practicing Engineer. Kent, England: Ann
Arbor Science Publishers.
4. U.S. EPA. 1990. EPA Summary Report: Optimizing
Water Treatment Plant Performance with the Com-
posite Correction Program. EPA 625/8-90/017. U.S.
EPA Center for Environmental Research Information.
March.
5. Regli, S. 1990. Hows and Whys of CTs. Presented at
AWWA Annual Conference, Cincinnati, OH. June.
6. U.S. EPA. 1989. Guidance Manual for Compliance
with the Filtration and Disinfection Requirements for
Public Water Systems Using Surface Water Sources.
Science and Technology Branch, Criteria and Stand-
ards Division, Office of Drinking Water. NTIS No. PB-
90148016. Washington, DC: U.S. EPA.
8. Hibler, C.P. and C.M. Hancock. 1990. Waterborne
Giardiasis. In: Drinking Water Microbiology -
Progress and Recent Developments New York:
Springer-Verlag, Inc.
9. U.S. EPA. 1989. Surface Water Treatment Rule.
Federal Register, Vol. 54, No. 124, U.S. Environmen-
tal Protection Agency, 40 CFR, Parts 141 and 142,
Rules and Regulations, Filtration/Disinfection. June.
10. Renner, R.C., B.A. Hegg, and D.L. Fraser, 1989.
Demonstration of the Comprehensive Performance
Evaluation Technique to Assess Montana Surface
Water Treatment Plants. Presented at the 4th Annual
ASDWA Conference, Tucson, Arizona. February.
11. Safe Drinking Water Notes from Pennsylvania
Department of Environmental Resources. 1990.
Division of Water Supplies, Harrisburg, PA. August.
12. Cleasby, J.L., M.M. Williamson, and E.R. Baumann.
1963. Effect of Filtration Rate Changes on Quality.
Journal AWWA. 55:869-878.
13. Cleasby, J.L., A.H. Dharmarajah, G.L. Sindt, and
E.R. Baumann. 1989. Design and Operation
Guidelines for Optimization of the High Rate Filtration
Process: Plant Survey Results. Denver, CO: AWWA
Research Foundation and AWWA. September.
31
-------
Intentionally Blank Page
-------
CHAPTER 3
COMPOSITE CORRECTION PROGRAM
OBJECTIVE
The objective of a CCP is to achieve a desired level of
performance from an existing water treatment facility
without major modifications. If the results of a CPE indi-
cate a Type 1 plant (see Figure 2-1), then existing major
unit processes have been assessed to be adequate to
meet current treatment requirements. For Type 1
facilities, major plant modifications are not indicated and
the CCP can focus on systematically addressing iden-
tified performance-limiting factors to achieve the desired
finished water quality.
For Type 2 plants, existing major unit processes have
been determined to be marginal. Improved performance
is likely through the use of a CCP; however, the plant
may or may not meet performance objectives without
major facility modifications. For these plants, the CCP
focuses on obtaining optimum capability of existing
facilities. If the CCP does not achieve the desired
finished water quality, unit process deficiencies will be
clearly identified and plant administrators can be confi-
dent in pursuing the indicated facility modifications.
For Type 3 plants, major unit processes have been as-
sessed to be inadequate to meet performance objectives.
For these facilities, major construction is indicated and a
comprehensive study that focuses on alternatives to
achieve these construction needs is warranted. A study
of this type should look at long-term water needs, raw
water source or treatment alternatives, and financing
mechanisms. If existing plant performance has the poten-
tial to cause a serious public health risk, officials may
want to address serious operating problems to improve
plant performance until modifications can be imple-
mented. Since continuous acceptable performance can-
not be achieved with a Type 3 facility, administrative
actions such as a boil order or water restrictions have to
be initiated by regulators until improvement can be com-
pleted.
CCP METHODOLOGY
The methodology for conducting a CCP is a combination of
utilizing CPE results as a basis for followup, implementing
process control priority-setting techniques, and maintaining
long-term involvement to systematically train staff and
administrators responsible for water treatment.
CPE Results
Implementation of a CCP initially focuses on addressing
the prioritized list of performance-limiting factors that is
developed during a CPE. This list provides a plant-
specific outline of those items that must be addressed if
desired performance is to be achieved. A combination of
activities such as training, minor modifications, and
process control adjustments may all be used by the per-
son implementing the CCP to address identified factors.
It is important to note that additional performance-limiting
factors, not identified in the short duration of the CPE,
often become apparent during conduct of the CCP.
These factors must be addressed to achieve the desired
level of performance.
Setting Priorities for Process Control
The areas in which performance-limiting factors have been
broadly grouped (administration, maintenance, design, and
operation) are all important in that a factor in any one of
these areas can individually cause poor performance.
However, when implementing a CCP the relationship of
these categories to achieving the goal of desired finished
water quality must be understood. Administration, design,
and maintenance activities all lead to a plant physically
capable of achieving desired performance. It is the opera-
tion, or more specifically the process control activities, that
enables a physically capable plant to produce adequately
treated water. This concept is illustrated graphically in
Figure 3-1. Focusing on process control efforts when im-
plementing a CCP allows priorities to be developed for
making required changes to achieve improved perfor-
mance. In this way, the most direct approach to improve
performance is implemented.
For example, if filtered water turbidities cannot be consis-
tently maintained at required levels because operating
staff is not at the plant to make chemical feed adjust-
ments in response to changing raw water quality, then
improved performance will require better staff coverage.
In this case, identified limitations in meeting process
needs (e.g., limitations in making chemical feed adjust-
ments) establish the priority for improving staff coverage
33
-------
Figure 3-1. Relationship of performance-limiting factors to achieving a performance goal.
Design
Administration
Maintenance
Treated Water in Compliance
Capable Plant
Operation (Process Control)
(e.g., an administrative policy) at the plant. Additional
staff would alleviate the identified deficiency (e.g.,
provide a capable plant) and allow process adjustments
to be made, so that progress toward the performance
goal can be continued. Conversely, nonperformance-re-
lated improvements can be justifiably delayed utilizing the
same process control emphasis.
Long-Term Involvement
To be effective, implementation of a CCP must constitute
a long-term effort, typically involving several months up to
1 year, for several reasons:
• Greater effectiveness of repetitive training techniques.
Operator and administrator training can be conducted
under a variety of actual operating conditions (e.g.,
seasonal water quality or demand changes). This ap-
proach allows development of observation, interpreta-
tion, and implementation skills necessary to maintain
desired finished water quality during periods of vari-
able raw water quality.
• Time required to make minor facility modifications. For
changes requiring financial expenditures, both time
and a multiple step approach are typically required to
gain administrative (e.g., city council) approval. First,
the need for minor modifications must be
demonstrated through process control efforts. Then
council/administrators must be shown the need and ul-
timately convinced to approve the funds necessary for
the modifications. These activities normally take
several months before the identified modification is im-
plemented and operational.
• Time required to make administrative changes. Ad-
ministrative factors can prolong CCP efforts. For ex-
ample, if the utility rate structure is inadequate to sup-
port plant performance, extensive time can be spent
implementing required changes in the rate structure.
Communication barriers between "downtown" and the
plant or between staff members may have to be ad-
dressed for improved performance. If the staff is not
capable, personnel changes may have to be made for
the CCP to be successful.
• Time required for identification and elimination of any
additional performance-limiting factors that may be
found during the CCP.
Facilitator Tools
Experience has shown that no single approach can ad-
dress the unique combination of fjctors at every water
treatment plant; therefore, actual details of implementa-
tion must be site specific and should be left to the in-
dividual implementing the CCP. However, general
techniques that have been successfully used in im-
plementing CCPs are presented.
The individual that implements a CCP is called a
facilitator. This individual is typically an "outsider" and ac-
complishes the objectives utilizing periods of onsite invol-
vement (e.g., site visits) interspersed with offsite limited
involvement (e.g., phone calls). This approach is graphi-
cally illustrated in Figure 3-2. The function of site visits
and phone calls is further described below.
• Site visits are used by the facilitator to verify or clarify
plant status, initiate major process control changes,
test completed facility modifications, provide onsite
operator or administrative training, and report progress
to utility staff. Dates for site visits should be scheduled
as indicated by the plant status and training require-
34
-------
Figure 3-2. Typical scheduling of CCP activities.
Telephone
Consultation
On-site
Consultation
10
11
12
Months of Involvement
merits and not necessarily established at specific inter-
vals. As shown in Figure 3-2, fewer site visits and
telephone calls will typically be necessary as the CCP
progresses. This is in line with the transfer of respon-
sibility to the plant staff that occurs during the CCP.
The number of site visits required by a CCP facilitator
is dependent on plant size and on the specific perfor-
mance-limiting factors. For example, some administra-
tive (e.g., staffing and rate changes) and design
factors could significantly increase the number of site
visits required to complete a CCP. Typically 2 to 4
days are spent at the plant during site visits. A final
site visit is conducted to present a report.
• Telephone calls are used to routinely monitor CCP
progress. Routine phone contact is used to train and
encourage plant personnel concerning plant observa-
tions, data interpretation, and followup implementation
activities. Telephone calls are limited in effectiveness
in that the CCP facilitator must completely rely on ob-
servations of the plant staff. To enhance communica-
tion, the CCP facilitator should always summarize
important points, describe decisions that have been
reached, and identify actions to be taken. Further, both
the CCP facilitator and plant personnel should main-
tain written phone logs. Typically, 2 to 4 hours each
week are spent on phone calls and data development
and interpretation.
Specific tools have been used to increase the effec-
tiveness of site visits and telephone calls, and to en-
hance the transfer of capability for achieving and
maintaining desired finished water quality to plant ad-
ministrators and staff. These are further described
below.
• Contingency plans should be prepared for the oc-
casions where a CCP is initiated at a plant that is
producing unacceptable finished water quality, or
where a CCP is being conducted and finished water
quality deteriorates to an unacceptable level, The con-
tingency plan should include actions such as reducing
plant flow rate to improve performance, shutting down
the plant, initiating a voluntary public notification and
initiating a voluntary boil order. If plant finished water
exceeds a regulated maximum contaminant level
(MCL), the State regulatory agency should be immedi-
ately informed and public notification procedures man-
dated by the Public Notification Regulation Rule (1)
followed. To minimize the chance of producing unac-
ceptable finished water while conducting a CCP, all
experimentation with chemical doses and different
coagulant products should be done on a bench-scale
basis (e.g., jar test) before implementing changes on a
full-scale basis.
• Action-implementation plans should be developed and
updated by the facilitator throughout the CCP to en-
sure progressive implementation of performance im-
provement activities. The "Action" plan lists items to be
completed, including the name of the person that is as-
signed a particular task and the projected due date.
The plan is normally updated and distributed to ad-
ministrators and plant personnel after a site visit.
Phone calls are used to encourage and monitor
progress on the assigned action items. Figure 3-3
shows a sample "Action" plan.
• Special studies can be used to evaluate and optimize
unit processes, to document past performance, to
modify plant process control activities, or to justify ad-
ministrative or design changes necessary to improve
plant performance. They are a structured, systematic
approach of evaluating plant operating conditions The
format, which is shown in Figure 3-4, consists of a 1-
page writeup that defines the hypothesis, approach,
duration of the study, expected results, documenta-
tion/conclusions, and implementation plan. The
hypothesis should be narrow in scope and should
35
-------
Figure 3-3. Action-Implementation plan
Item Action/Implementation
clearly define the study to be conducted. The ap-
proach should provide a detailed procedure of how the
study is to be conducted, including when and where
samples are to be collected, who is to collect the
samples, what analyses are to be conducted, and how
the results are to be tabulated. This approach should
be developed in cooperation with the plant staff to ob-
tain staff commitment and to eliminate "bugs" on paper
prior to beginning the study. It is important that the
study results be documented using tools such as
graphs, figures, or tables. This allows the findings to
be presented to the plant staff, administrators, State
inspectors, or other "observers" as a basis for a
change in plant operation, design, maintenance, or ad-
ministration leading to improved plant performance. An
implementation plan together with documentation ad-
dresses procedural changes and support required to
implement special study results. If all of the steps are
followed, the special study approach ensures involve-
ment by the plant staff, serves as a basis for ongoing
training, and increases confidence in plant capabilities.
Appendix F presents a sample special study.
• Operating procedures can be used to formalize ac-
tivities that are essential to ensure consistent plant
performance. Examples of procedures that can be
developed include jar testing, polymer dilution prepara-
tion, polymer and coagulant feed calculations, filter
backwashing, and chemical feeder calibration. Proce-
dures are most effective if they are developed by the
plant staff. Through the staff's participation, operator
training is enhanced and operator familiarity with
equipment manuals and operating procedures is ob-
tained. Also, when operators are able to prepare a pro-
cedure, it indicates that they have gained a thorough
understanding of the water treatment process that was
discussed. The procedures should be assembled in a
three-ring binder so they can be easily removed and
modified as plant operating practices dictate. A sample
procedure is presented in Appendix G.
• Process control data sheets are used to formalize the
recording of results of process control testing that is in-
itiated. Typically, a daily sheet is used to record results
Person Responsible Date Due
4/4
5/1
4/17
4/24
4/28
of tests, flow data, chemical use, etc. These data are
transferred to a monthly sheet that allows observation
and trending of the data. Examples of daily and month-
ly process control sheets are presented in Appendix H.
• Graphs or trend charts can be used to enhance the in-
terpretation of process control results. The data
developed can be plotted over long periods to show
seasonal trends, such as changes in water demand, or
over shorter periods to show instantaneous perfor-
mance. As an example, raw, settled, and filtered
water turbidities were plotted over a 1-day period, as
Figure 3-4. Special study format.
Special Study Name:
Hypothesis:
Narrow in scope. Try to show definite cause/effect
relationship.
Approach:
Detailed procedure of conducting study. Involve
plant staff in development.
Duration of Study:
Important to define limits of the study since "extra
work" is typically required.
Expected Results:
Projections of results focus attention on interim
measurements and define success or limitations of
effort.
Conclusions:
Documented impact of study allows the effort to be
used as a training tool for all interested parties.
Allows credit to be given for trying an approach.
Implementation:
Changes or justifies current operating procedures.
Formalizes the mechanisms to improve plant
performance.
1 Develop calibration curve for polymer feed pump. Steve
2 Draft special study procedure to evaluate impact on performance of
reducing plant flow to 1,000 gpm. Steve
3 Process control,
a. Develop daily data sheet. Rob
b. Develop routine sampling program. Bob
c. Draft procedure for daily sampling and recording of data. Rob/Bob
36
-------
shown in Figure 3-5. During this period, no change in
coagulant dose was initiated, despite the change in
raw water turbidity. As a result, settled water and
finished water quality deteriorated several hours after
the raw water turbidity increased. Without the use of a
trend chart, the correlation demonstrated would be dif-
ficult to observe.
• A coagulant control technique must exist or be imple-
mented during a CCP if optimized performance is to
be achieved. Coagulant control techniques include jar
testing, streaming current monitors, zeta potential, and
pilot filters. Jar testing is the most common technique
and is discussed in more detail below.
To successfully implement jar testing as a coagulant
control technique requires understanding of making
stock solutions and conducting the test so that it dupli-
cates plant operating conditions as closely as pos-
sible. A typical procedure for preparing stock solutions
and conducting jar tests is shown in Appendix I. Stock
solutions must be prepared for any coagulant chemical
(e.g., metal salts and polymers) that is going to be
added to the jars.
The jar test can be set up to represent plant operating
conditions by determining actual plant theoretical
mixing, flocculation, and sedimentation detention
times; and by setting jar test mixing energy inputs,
mixing times, and settling times to values similar to
those in the plant. For Phipps and Bird jar testers,
Figure 3-6 can be used to determine paddle speeds
required to obtain desired G-values. The jar test proce-
dure should then be adjusted as necessary to obtain
results similar to actual plant operation. Actual plant G-
values can be determined by using worksheets
presented in the design section of Appendix C. The
use of square jars is recommended because ex-
perence has shown the square jars result in more rep-
resentative jar tests than round graduated cylinders
since square jars break up the circular motion inherent
in the cylinders.
Chemicals should also be added to duplicate plant
conditions. For example, if alum is added to the plant
flash mix and polymer is added to a pipeline ap-
proximately 30 seconds downstream from the flash
mix, the same sequence should be used in the jar test.
The use of syringes without needles to measure and
deliver the appropriate chemical dose to each jar (typi-
cally six jars are used) simplifies the chemical addition
step. Syringes without needles are available from
pharmacies or veterinary/farm supply stores,
Figure 3-5. Trend chart showing relationship of raw, settled, and filtered water.
FILTERED
12
TIME (hrs)
37
-------
Figure 3-6. Velocity gradient versus rpm at various
temperatures (°C) for a 2-liter square beaker,
using a Phlpps and Bird stirrer (2).
300
200
u
9
C
O
re
U
>¦
20 '
200 300
100
Agitator Paddle Speed, rpm
Another essential step in the successful use of a jar
test for coagulant control is the interpretation of the
test results. In direct filtration plants, a small volume
(about 50 mL) should be removed from the jars and
passed through filter paper. Whatman #40 or
Schleicher and Schuell #560 filter paper can be used
to approximate filter performance. The filtered samples
should be tested for turbidity, and the sample with the
lowest turbidity represents the optimum chemical
dose.
In conventional plants, the jar contents should be al-
lowed to settle for the same time as represented by
the actual plant. Samples should then be drawn from
the sample tap located 10 cm from the top of the jar,
and the turbidity of the sample should be determined.
The lowest turbidity represents the best chemical
dosage. If sample taps are not available on the jars,
pipettes can be used to draw off samples from the jars.
Excellent references are available to guide the
facilitator in implementing jar testing techniques to ob-
tain optimum coagulant doses (2,3,4).
• Letter reports are recommended to promote clarity and
continuity. Since a CCP is an action-oriented program,
only concise status reports are recommended. Short
(1-page) written summaries should be prepared after
each site visit and for each facility modification. Initially
reports should be prepared by the CCP facilitator, but
the responsibility should ultimately be transferred to
the plant staff.
• A final CCP report should be prepared to summarize
activities. Since all major recommendations should
have been implemented during the CCP, current
status of the plant performance should be the main
focus of this report.
Correcting Performance-Limiting Factors
The major emphasis of a CCP is addressing factors iden-
tified as limiting performance. Correcting these factors
produces a capable plant and allows improved process
control (operation) to move the plant to continuous com-
pliance with applicable water quality regulations. Ac-
tivities that can bo conducted to address factors in the
areas of design, administration, maintenance, and opera-
tion are discussed below.
Improving Design Performance-Limiting Factors
The performance of Type 2 and 3 plants may be limited
by design factors that require major modifications to cor-
rect. Major modifications require the development of en-
gineered drawings and specifications, and hiring a
construction company to complete the improvements.
Examples of such improvements include adding a
sedimentation basin or filter. Major modifications can
often be avoided by operating the plant at a lower flow
rate for longer periods of time; thereby reducing the unit
process hydraulic loading rate to a range that allows ade-
quate performance to be achieved.
The performance of Type 1 and Type 2 plants can often
be improved by making minor modifications or additions
to the plant. A minor modification is defined as a
modification that can be completed by the plant staff
without development of drawings and specifications.
Minor modifications include improvements such as ad-
ding a chemical feeder, developing additional chemical
feed points, or installing baffles in a sedimentation basin.
Examples of design limitations that have been identified
are included in Appendix J. A conceptual approach to im-
proving design performance-limiting factors follows.
Ideally, the CCP facilitator and plant personnel should be
able to justify each proposed plant design modification
based on the resulting increased performance capability
that the modification will provide. A sound basis is to re-
late design modifications to the need to provide a
capable plant such that process control objectives can be
met (see Figure 3-1). The degree of justification required
usually varies with the associated costs and specific plant
circumstances. For example, little justification may be re-
quired to add a sampling tap to a filter effluent line.
Whereas, justification for adding baffles to a flocculation
basin would require much more emphasis. Additionally,
extensive justification may be required for a facility where
38
-------
water rates are high and have recently been raised, yet
there is no money available for an identified modification.
The CCP facilitator should transfer to the plant staff the
capability to formally document the need for minor
modifications. This documentation is valuable in terms of
presenting a request to supervisory personnel and in
providing a basis lor the plant staff to continue such re-
quests after the CCP has been completed. For many re-
quests, the special study lormat can be used as the
approach for documenting the change (see "Facilitator
Tools", p. 34). For modifications with a larger cost, the
following items may have to be added to the special
study format.
• Purpose of the proposed change (e.g., how does the
change relate to the development of a capable plant
so that process control can be used to improve perfor-
mance).
• Detailed description of the change and an associated
cost estimate.
Many State regulatory agencies require that modifica-
tions, other than repair and maintenance items, be sub-
mitted for their approval. Improvements requiring State
approval may consist of items such as changing types of
chemicals added to the water (e.g., substituting iron salts
for aluminum salts), adding another chemical (e.g., filter
aid polymer) feeder, or modifying filter media. If there is
any doubt as to whether approval is needed, the
facilitator should recommend submitting the proposed
modification to the regulatory agency for approval.
Once the proposed modification has been approved by
plant administrators and the State regulatory agency, the
CCP facilitator should serve as a technical and
managerial reference throughout the implementation of
the modification. Following completion of a modification,
the CCP facilitator should ensure that a formal presenta-
tion of the improved plant capability is presented to the
administration. This feedback is necessary to build rap-
port with the plant administrators and to ensure support
for future requests. The intent of the presentation should
be to identify the benefits in performance obtained from
the resources expended.
Improving Maintenance Performance-Limiting
Factors
Maintenance can be improved in nearly all plants, but it is
a significant performance-limiting factor in only a small
percentage of plants (5,6). The first step in addressing
maintenance factors is to document any undesirable
results of the current maintenance effort. If plant perfor-
mance is degraded as a result of maintenance-related
equipment breakdowns, the problem is easily docu-
mented. Likewise, if extensive emergency maintenance
events are experienced, a need for improved preventive
maintenance is easily recognized. Ideally, maintenance
factors should have been previously identified and
prioritized during a CPE. However, most plants do not
have such obvious evidence directly correlating poor
maintenance practices with poor performance; therefore,
maintenance factors often do not become apparent until
the conduct of a CCP.
Simply formalizing recordkeeping will generally improve
maintenance practices to an acceptable level in many
plants, particularly smaller ones. A suggested four-step
procedure for developing a maintenance recordkeeping
system is to 1) list all equipment; 2) gather
manufacturers' literature on all equipment; 3) complete
equipment information summary sheets for all equipment;
and 4) develop time-based preventive maintenance
schedules. Equipment lists can be developed by touring
the plant and by reviewing available equipment manuals.
As new equipment is purchased it can be added to the
list. Existing manufacturers' literature should be inven-
toried to identify missing but needed materials. Main-
tenance literature can be obtained from the manufacturer
(usually a source is identified on the equipment name
plate) or from local equipment representatives. Once
sheets are completed for each piece of equipment, a
time-based schedule can be developed. This schedule
typically includes daily, weekly, monthly, quarterly, semi-
annual, and annual checkoff lists of required main-
tenance tasks.
The above system for developing a maintenance
recordkeeping system has worked successfully at
numerous plants. However, there are many other good
maintenance systems, including computer-based sys-
tems. The important concept to remember is that ade-
quate maintenance is essential to achieve consistent
treated water quality.
Improving Administrative Performance-Limiting
Factors
Administrators who are unfamiliar with plant needs, and
thus implement policies that conflict with plant perfor-
mance, are a commonly identified factor. For example,
such items as implementing minor modifications, pur-
chasing testing equipment, or expanding operator
coverage may be recognized by plant operating person-
nel as needed performance improvement steps, but
changes cannot be pursued due to lack of support by
nontechnical administrators. Administrative support and
understanding are essential to the successful implemen-
tation of a CCP. The following techniques have proved
useful in addressing identified administrative factors limit-
ing performance:
• Build a rapport with administrators such that candid
discussions concerning physical and personnel resour-
ces can take place.
• Involve plant administrators from the start. Initial visits
should include time with key administrators to explain the
39
-------
process and possibly include a joint plant tour to in-
crease their understanding of plant processes and
problems.
• Focus administrators on their responsibility to attain a
"product" that not only meets but exceeds regulatory
requirements on a continuous basis. Often ad-
ministrators are reluctant to pursue actions aimed at
improving plant performance because of a lack of un-
derstanding of both the health implications associated
with operating a water treatment plant and of their
responsibilities in producing a safe finished water. Ad-
ministrators must be informed that even momentary
excursions in water quality must be avoided to prevent
pathogenic organisms, including cysts, from passing
through the treatment plant and into the distribution
system. Such a breakdown in treatment could result in
sickness of numerous consumers. Administrators must
understand that to minimize the exposure of con-
sumers to pathogenic organisms in their drinking water
all unit processes must be performing optimally on a
continuous basis. This provides a "multiple barrier" to
prevent passage of pathogenic organisms through the
treatment plant. Establishment and continuous
achievement of high quality treated water goals virtual-
ly guarantees that pathogenic organisms will not reach
consumers. As such, administrators should be con-
vinced to establish goals for high quality treated water
(e.g., 0.1 NTU) and to emphasize to the operating staff
the importance of achieving these goats.
• Listen carefully to the concerns of administrators so
that they can be addressed. Some of their concerns or
ideas may be technically unimportant, but are very im-
portant "politically." Political influence as well as tech-
nical requirements must be addressed and are
considered to be an integral part of the activities of a
CCP facilitator.
• Use technical data based on process needs to con-
vince administrators to take appropriate actions; do not
rely on "authority."' Alternatives should be presented,
when possible, and the administrators left with the
decision.
• Solicit support for involvement of plant staff in the
budgeting process. Budget involvement has been ef-
fective in encouraging more effective communication
and in motivating plant staff.
• Encourage development of a "self-sustaining utility" at-
titude. This requires financial planning for modification
and replacement of plant equipment and structures,
which encourages communication between ad-
ministrators and plant staff concerning the need to ac-
complish both short- and long-term planning. It also
requires development of a fair and equitable rate struc-
ture that requires each water user (domestic, commer-
cial, and industrial) to pay his or her fair share. The
revenues generated should be sufficient to support
long-term as well as short-term modification and re-
placement costs plus provide for ongoing items such
as proper staffing, training, and chemical supplies.
Reference materials are available to assist the CCP
facilitator in guiding activities in this area (7,8,9,10,11).
• Encourage long-term planning for future water sup-
plies and facility improvements necessary to meet
more stringent water quality requirements.
Improving Operational Performance-Limiting Factors
Improvement of plant performance is ultimately achieved
by providing process control procedures, tailored for the
particular plant, that can be used to move a capable
facility to the desired finished water quality goal. Initial ef-
forts should be directed toward the training of the key
process control decision-makers. In most plants with
flows less than 1,900 m3/d (0.5 MGD), one person typi-
cally makes and implements all major process control
decisions. In these cases, on-the-job training is usually
more effective than classroom training and is recom-
mended. If possible, in plants of this size a "backup" per-
son should also be trained. This "backup" may be a
board or council member at a very small utility. As the
number of operators to be trained increases with plant
size, the need for and effectiveness of combining class-
room training with on-the-job training also increases.
Since on-the-job training, or site-specific training greatly
enhances the operators' capability to apply knowledge,
this "hands-on" approach must be an integral part of any
CCP. Process control for water treatment facilities is dis-
cussed below.
Process Sampling and Testing
Successful process control of a water treatment plant in-
volves producing a consistent, high quality treated water
from an often highly variable raw water surface source.
To accomplish this goal, it is necessary that the perfor-
mance of each unit process be optimized. This is impor-
tant because a breakdown in any one unit process places
a greater burden on the remaining processes and in-
creases the chance of viable pathogenic organisms
reaching the distribution system and consumers taps. By
optimizing each unit process, the benefits of providing
multiple barriers prior to distribution to the consumers is
realized.
To optimize each unit process, information must be
routinely obtained and recorded on raw water quality and
on the performance of the various unit processes in the
plant so that appropriate controls can be exercised to
maintain consistent treated water quality. The term
routinely is stressed because it is necessary to have the
plant staffed at all times it is in operation to allow informa-
tion to be gathered and for process control adjustments
to be made whenever water quality conditions dictate.
The gathering of information in an organized and struc-
40
-------
tured format involves development of a process control
sampling and testing schedule.
Figure 3-7 shows a process control schedule for a con-
ventional plant. As shown, turbidity is one of the primary
tests because it provides a quick and easily conducted
measurement to determine approximate raw water
quality and the effectiveness of individual plant unit
processes. Raw water turbidity should be conducted on a
frequent basis (e.g., every 4 hours) to identify changes in
raw water quality. During periods of rapid change, raw
water turbidity may be measured on a more frequent
basis to allow adjustment of coagulant aids. Settled water
turbidity should be measured a minimum of every 2 hours
to monitor the effectiveness of the settling process and to
determine if something unexpected, such as failure of an
alum feeder, has occurred. Filtered water turbidity should
be measured and recorded on a continuous basis to
allow constant monitoring of filtered water quality. Con-
tinuous monitoring of filtered water tremendously enhan-
ces the operators' capability to properly time
backwashing of filters, to determine the extent of
postbackwash turbidity breakthrough, and to observe if
filter-regulating valve fluctuations are impacting filtered
water turbidity.
The process control data should be recorded on daily
sheets, and these data should be transferred to monthly
sheets to allow observation of water quality trends. Ap-
pendix H includes examples of both daily and monthly
process control sheets. The daily sheets should include
space for recording actual chemical feed rates and the
conversion of these values to a mg/L dosage so that
dosage and water quality can be correlated. This data
base then can be used by the operator to better predict
chemical feed requirements when raw water quality char-
acteristics change suddenly. Graphs and trend charts
greatly enhance these correlation efforts.
Chemical Pretreatment
The selection and control of chemical coagulants, floc-
culants, and filter aids are the most important aspects of
improving water treatment plant performance. As a rule,
these considerations are more important than the physi-
cal facilities available to treat the water. Therefore, a
method to evaluate different coagulants and to control
the coagulant selected is a primary focus in implementing
a process control program. The special study format is
especially effective for systematically optimizing chemical
pretreatment.
Several methods exist to determine proper coagulant
dosages in conventional plants, including jar testing, zeta
potential, and streaming current monitors. Jar testing is
the most common procedure used. Once the correct
chemical dose is determined, the staff must be able to
adjust the chemical feeders to deliver the desired
dosage. This requires the ability to conduct chemical cal-
Figure 3-7. A process control sampling and testing schedule for a small water treatment plant.
Sample
Plant Influent
Reactor
Clarifier
Sample Location
Tests
Tap by raw water
turbidimeter
Weir No.1
Sample Tap
Turbidity
pH
Alkalinity
Flow Rate/Total
Jar Test
Temperature
Turbidity
Visual Sludge Check
Frequency
Continuous
Daily
Weekly
Continuous
As Needed
Daily
3 Times/Day1
Daily
Sample By
Meter
Operator
Operator
Meter
Operator
Operator
Operator
Operator
Filter
Effluent
Turbidimeter
Lab Tap
Turbidity
pH
CI2 Residual
Turbidity
Continuous
Daily
Continuous
Every 4 Hrs.
Meter
Meter
Operator
Operator
When operating reactor clarifier in the solids contact mode (i.e., with a sludge blanket),
the following additional testing is required:
Reactor Mixing Well % Solids By Volume Daily @ Noon Operator
Clarifier UpflowArea Blanket Depth 3 Times/Day1 Operator
1Startup, noon, shutdown.
41
-------
dilations and to develop and utilize calibration curves for
chemical feeders. For example, a mg/L dose may have to
be converted to a lb/day or mUmin feed rate in order to
correctly adjust a chemical feeder. Calibration curves
which indicate feed rate setting versus feeder output
must be developed for all chemical feeders to allow the
correct feeder setting for a given desired chemical
dosage. Some chemicals, such as non-ionic or anionic
polymers, must often be prepared in dilute solutions prior
to introduction into the plant flow stream. Therefore, the
capability to prepare chemical dilutions must be imparted
to the operators during the CCP. Appendix K presents
chemical feed calculations and Appendix G shows a pro-
cedure to develop a chemical feeder calibration curve.
Chemical addition must not only be carefully controlled,
but the correct type of coagulants, flocculants, and filter
aids must be applied. Typically, a metal salt and cationic
polymer should be added prior to flocculalion. The metal
salt should always be added to the rapid mix; however,
the addition point of the cationic polymer, which may be
before, after, or into the rapid mix, should be determined
on a site-specific basis by conducting a special study. If
alum is being utilized with a raw water pH exceeding 8.0
to 8.5, consideration should be given to switching to
iron salts, sodium aluminate, or polymerized products.
The use of a flocculant polymer to enhance floe forma-
tion and settling can also be investigated. Investigation
of filter aid polymers should be conducted since these
aids are typically required if filtered water turbidities less
than 0.1 NTU are to be achieved on a continuous basis.
These products should be introduced into the plant flow
stream at a point of gentle mixing, since excessive tur-
bulence will shear the polymer chains and make the
product ineffective.
Competing chemicals should not be added at the same
location. For example, the addition of lime and alum at
the same point is counterproductive if the lime is raising
the pH to the extent that the optimum range for alum
coagulation is exceeded. The addition of powdered ac-
tivated carbon at the same location as chlorine is also
detrimental since the carbon will quickly adsorb the
chlorine, inhibiting the ability of both chemicals. The addi-
tion of chlorine, potassium permanganate, or other
oxidant, in combination with some polymers, will result in
the oxidation of the polymer, with a subsequent reduction
in its effectiveness.
Unit Process Controls
Mixing, Flocculation, and Sedimentation. The controls for
mixing, flocculation, and sedimentation unit processes
normally include the following:
• Plant flow rate
• Type of chemical and chemical feed rate (pre-
viously discussed)
• Flocculation energy input
• Sludge removal
Plant flow rate is a primary control at many small plants
that are operated for less than 24 hours each day. At
these plants an excessive hydraulic loading rate on the
flocculation/sedimentation processes can be avoided by
operating at a lower flow rate for a longer period of time.
This provides an option to meet more rigorous perfor-
mance requirements with existing units without major
capital improvements. The capability to reduce plant flow
rate to improve performance is offset by the need to staff
the plant for longer periods of time, which adds to operat-
ing costs. Therefore, plant administrators, in conjunction
with the CCP facilitator, must evaluate both options.
Flocculation energy input is often fixed at small plants,
either by hydraulic flocculation systems or by constant
speed flocculation drives. However, flocculation energy, if
tow enough to allow formation of settleable floe, is riot
considered an essential variable to achieve desired per-
formance of a small plant. More important are the plug
flow characteristics of the flocculation system. Plug flow
characteristics, similar to those found in most hydraulic
flocculation systems, result in the formation of floe par-
ticles of uniform size, which greatly aids settleability. As
such, greater priority may be placed on installing baffling
in flocculation systems rather than trying to optimize
mixing energies. Adequate time for chemical reaction is
typically more important in water less than 5°C, and this
time can often be extended operationally by reducing
plant flow rate.
Inadequate removal of sludge from sedimentation basins
has generally not been a frequently identified factor limit-
ing performance of sedimentation basins. To prevent a
negative impact on performance, sludge need only be
removed from conventional sedimentation basins fre-
quently enough to prevent solids carryover to the filters. If
it is desired to optimize sludge removal, the frequency of
sludge removal can be determined by using a core
sampler to monitor buildup in the basin. The duration of
sludge removal can be determined by collecting samples
during sludge removal (e.g., every 30 seconds) and
determining when the sludge begins to thin. A centrifuge,
graduated cylinder, or Imhoff cone can be used for the
density analysis.
Sludge control is very important in the operation of reac-
tor type upflow sedimentation basins. The reactor section
of the basin must be monitored daily and the appropriate
amount of sludge removed from the basin to maintain the
optimum reactor concentration and basin floe blanket. In-
adequate monitoring of the basin can lead to a loss of the
sludge blanket over the weirs, which significantly impacts
basin and ultimately filter performance. A 100 mL
graduated cylinder has been used to monitor sludge
mass in a reactor type basin. A concentration of 18 to 25
42
-------
mL of sludge in a 100 mL cylinder after 5 minutes of set-
tling has provided satisfactory performance at one loca-
tion (12).
Filtration. The controls for the filtration process normally
include the following:
• Coagulation control
• Filtration rate control
• Filter aid chemical and chemical feed rate
• Backwash frequency, duration, and rate
• Backwash to waste
Proper chemical pretreatment of the water prior to filtra-
tion, as discussed previously, is the key to acceptable fil-
ter performance. Improper coagulation (either underfeed
or overfeed of coagulant) fails to produce particles that
are large enough to be removed within the filter. There-
fore, for waters that are properly chemically conditioned,
flow rate is not as important a parameter. If the flow rate
is constant and the water is properly conditioned, mixed
media or deep bed monomedia filters can be operated at
rates as high as 590 m3/m2/d (10 gpm/ft2) (13).
The most important aspect of flow rate relative to filter
performance is the magnitude of a change in flow rate
and the speed at which the change occurs (5,14). Rapid,
high magnitude, flow rate increases cause a high number
of particles to be washed through the filter as evidenced
by significant increases in turbidity. This breakdown in fil-
ter performance, which allows previously removed par-
ticles to pass into the distribution system, disrupts the
continuous performance that is required in water treat-
ment. Since the filters are the most effective barriers to
cysts, even short-term performance problems can poten-
tially expose consumers to significant concentrations of
cysts. It is noted that these "performance failures" can
occur even when the finished water turbidity regulations
are being met.
Filtration rate changes most often occur when a filter is
removed for backwashing, high volume constant speed
raw water pumps are cycled on and off, a filter is started
when it is dirty, or a filter rate controller is malfunctioning.
When a filter is removed from service for washing, many
plant staffs leave plant flow rate the same and direct the
entire plant flow to the remaining filter or filters. This
places an instantaneous, high magnitude flow increase
on the remaining filters, causing attached particles to be
swept out of the filter. This can be prevented by lowering
the plant flow rate prior to removing the filter from ser-
vice, thereby controlling the hydraulic loading on the fil-
ters remaining in service.
Starting dirty filters results in a rapid increase in flow rate
and subsequent poor filtered water quality. Backwashing
of filters prior to returning them to service is essentia! to
maintain the integrity of this unit process. Rapid changes
in plant influent flow by starting and stopping constant
speed raw water pumps also hydraulically pushes par-
ticles through filters. This may be prevented by using a
control valve (automatic or manual) to slowly adjust plant
influent flow rate. Malfunctioning filter rate control valves
can result in rapid changes in filter flow rate. An ongoing
preventive maintenance program is necessary to keep
the valves in good working order and avoid this source of
poor filter performance. If the hydraulic loading rate that
the filters are expected to handle is too high, reduction of
flow rate to the plant should be considered.
The utilization of a low dose of filter aid polymer can also
improve the filtered water quality of dual or mixed media
fillers. These products are very effective and can quickly
blind a filter; therefore, they should be used at optimum
doses (generally less than 0.1 mg/L) to avoid excessively
short filter runs. These products are subject to shearing
because of their long polymer chains and should be fed
at points of low turbulence, such as flocculation basins or
sedimentation basin effluent lines.
Filters must be backwashed at frequent enough intervals
to prevent small particles from passing through the filters.
Filtered water turbidity should be monitored continuously
and the filter backwashed at the first indication of an in-
creasing trend in turbidity. As a general rule, filters should
be washed after filtering about 204 m3/m2 (5,000 gal-
lons/ft2) per cycle (15). This corresponds to filter runs of
21 to 42 hours at filtration rates of 235 m3/m2/d (4
gpm/ft2) and 117 m3/m2/d (2 gpm/ft2), respectively. Very
long filter runs should be avoided because they can
make tilters difficult to clean during backwash due to
compaction of the media and can cause an increase in
biological growth on the filter. The maximum length of fil-
ter run can be determined by conducting a special study
involving microscopic evaluations of filtered water
throughout the filter run (16,17).
The filter backwash duration and intensity must be great
enough to clean the filter; but not so great as to damage
the support gravels/underdrain system or to blow media
out of the filter. The length of wash should be long
enough to result in clean spent backwash water because
inadequate washing can result in a degradation of filter
performance and the possible formation of mudballs.
The filter should be probed periodically (semi-annually or
annually) to inspect for support gravel problems and to
check media depths. Proper cleaning can be evaluated
by inspecting the filter media for mudballs and overall
cleanliness, and by conducting a filter bed expansion
test. A properly washed filter should have a minimum of
20 to 25 percent expansion of sand and anthracite.
Operating procedures should be developed to describe
consistent methods of backwashing filters. The proce-
dure should include measures to prevent rapid flow rate
increases to the remaining filter(s), to ensure the filter is
properly cleaned, and to prevent damage to the filter by
operating valves too quickly. The method of returning a
filter to service should also be described because this is
43
-------
another time when degraded filter performance can
occur. This degradation can be minimized by optimizing
coagulant and filter aid doses and by increasing the filter
rate gradually when returning a recently washed filter to
service. At some plants where it is difficult to achieve
high quality filtered water in less than 10 to 15 minutes, a
minor modification allowing filter-to-waste capability may
be justified. This allows directing the initial filtered water
to a drain until quality improves to the extent that the
water can be redirected to the clearweil.
Disinfection. The controls for the disinfection process nor-
mally include the following:
• Hydraulic flow rate (controls contact time)
• Disinfectant concentration
• Disinfectant application point
To prove adequate disinfection, the plant unit processes,
including disinfection, must meet a State-specified criteria
for log reduction of viruses and Giardia. Presently, this
criteria is defined as achieving a CT outlined in the
SWTR Guidance Manual (18). The CT value, which is the
concentration of disinfectant (mg/L) multiplied by the ef-
fective contact time (minutes) the disinfectant has with
the water prior to the first user's tap, is affected both by
plant flow rate and the concentration of the disinfectant
applied. Most plants apply chlorine as a disinfectant to
the filtered water prior to a clearweil. The clearweil is
generally designed as a storage basin for backwash
water or a wet well for finished water pumps and not as a
disinfectant contactor. As a result, there are no baffles or
other means to make the basin plug flow and the basins
are typically small, which provides limited contact times.
Reducing the plant flow rate or baffling the basin can
often gain more effective contacting. The maximum con-
centration of disinfectant that can be added because of
health and aesthetic (public complaint) concerns is nor-
mally 2.5 mg/L as free chlorine residual.
Adding a chlorine application point prior to the plant rapid
mix to try to gain contact time afforded by raw water
transmission lines, and flocculation and sedimentation
basins can be evaluated. However, this practice, while al-
lowing greater CT values to be obtained, may cause the
formation of excessive disinfection byproducts. State
regulatory personnel should be consulted prior to initiat-
ing this practice.
If operational changes cannot be made to achieve the
specified CT values, modifications to the plant may be re-
quired to provide sufficient disinfectant contact time. It is
noted that actual levels of disinfection required for water
treatment plants will be determined by the State where
the plant is located. Modifications to a plant's disinfection
system should not be pursued until the State regulations
are finally developed.
CONDUCTING A CCP
Initial Site Visit
A good working relationship between the CCP facilitator
and the plant staff and administration should be estab-
lished during the initial site visit. Such a relationship—
based on mutual respect, communication, and under-
standing the objective of the CCP—greatly enhances the
potential for success. During the initial site visit, CPE
results are used to prioritize followup activities, ideally,
activities for addressing all major performance-limiting
factors (rated "A" or "B" in the CPE) should be initiated.
Before implementing any major changes, the facilitator
must carefully consider the potential adverse impact on
plant performance and public health. The actions are site
specific depending on the level of severity of the perfor-
mance problem and the applicable regulations in the
State where the plant is located. However, contingency
plans should be prepared for the case where a CCP is in-
itiated at a plant that is producing unacceptable finished
water quality (see "Facilitator Tools", p. 34). Actions
could include shutting down the plant, lowering plant flow
rate, or initiating an order to boil water. In all cases, the
appropriate health department officials must be notified of
the problem. If process adjustments, such as coagulant
feed, are grossly out of line, the facilitator should initiate
process adjustments to minimize the adverse effect of
the treated water. Jar tests or other bench-scale testing
should be done prior to initiating a process adjustment in
order to avoid full-scale experimentation that could ac-
tually result in a further deterioration in treated water
quality. Following is an example of actions taken by a
CCP facilitator during an initial site visit at a plant where
treated water turbidities exceeded 6 NTU:
When the turbidity violation was noticed the plant
was inspected to ensure all plant equipment, includ-
ing chemical feeders, was operating properly. Jar
testing was then initiated to determine the correct
range for coagulant dosage. It was determined that
the actual alum feed rate was approximately 200 per-
cent high so the feed rate was immediately adjusted
to a more appropriate level. State regulatory person-
nel who were in attendance at the initial site visit,
called their supervisor and initiated a boil order for
the community and required the plant staff to provide
daily, detailed monitoring reports. Plant performance
improved to the extent that finished water met tur-
bidity regulations before the end of the day.
After a contingency plan has been developed to ensure
protection of public health, the CCP facilitator can begin
directing the implementation of process control adjust-
ments to optimize plant performance. Changes in
process control direction must be made with considera-
tion of the operators' morale. All recommendations for
process control changes should be thoroughly explained
44
-------
prior to implementation. Even with this approach, a CCP
facilitator should not expect to obtain immediate en-
thusiastic support from plant personnel, A response such
as "well let's try it and see" is often the best that can be
expected. Some changes may have to be made with
only the degree of consensus expressed with the state-
ment, "I don't think it will work, but we can try it."
If operations factors are top ranking, the initial site visit
should be used to introduce the staff to proper process
control activities, such as conducting jar tests and chemi-
cal feed calculations (see "Facilitator Tools", p. 34). Exist-
ing coagulant and flocculation/filtration chemicals should
be utilized in initial adjustments. Special studies can be
initiated later in the CCP to determine the effectiveness
or necessity of alternative chemicals.
Understanding how to determine correct chemical
dosages and how to set the chemical feeders is extreme-
ly important because chemical pretreatment is normally
more important in achieving optimum plant performance
than physical facilities. Procedures that clearly describe
these activities should be reviewed, or developed if they
don't exist, during the initial visit. The plant staff then has
a written description that can be consistently followed.
Procedures for calibrating a chemical feeder, conducting
a jar test, and calculating an alum feed rate are
presented in Appendices I and K. Existing process con-
trol testing should also be reviewed and modified so that
all necessary process control elements are adequately
monitored. Sampling frequency and location, collection
procedures, and laboratory analyses should be reviewed
and, if necessary, standardized so that data collected can
be used for evaluating progress. New or modified sam-
pling and analysis procedures should be demonstrated
and documented.
Often, necessary process control equipment is not avail-
able at the plant. Any needed sampling or testing equip-
ment should be noted and the purchasing process should
be implemented as quickly as possible. Provisions may
be made for loaner equipment for essential items such as
a jar tester to determine proper coagulant doses. The
CCP facilitator should assist plant personnel in obtaining
administrative approvals.
Data sheets, which summarize process control parameters
and performance monitoring results, should be developed.
Sample daily and monthly process control forms for a small
plant are shown in Appendix H. It is important that a com-
mon understanding of information on the summary sheets
be reached during the initial site visit since they will be used
by the plant staff to provide data to the CCP facilitator
throughout the CCP. The CCP facilitator reviews the data,
sets operating targets, and makes process control decisions
in conjunction with the plant staff. Often, weekly summaries
of data are used. However, if computer capability is avail-
able, electronic transfer of data can be used to allow daily
data exchange.
Often times plant performance is limited by the perfor-
mance goals established by utility personnel. For ex-
ample, some plants only try to achieve a finished water
quality of 1.0 NTU because that was the regulated stand-
ard. This attitude negatively affects the attainment of op-
timum unit process performance (multiple barriers) and
continuous finished water quality that minimizes public
exposure to pathogenic organisms. It is essential that the
facilitator work with plant staff and administrators to es-
tablish aggressive treatment goals during the initial site
visit and to instill in the operators and administrators the
tenacity to achieve those goals. Targets for effluent tur-
bidity that are typically established at a plant are 1 to 2
NTU from sedimentation facilities and less than 0 1 NTU
from filters. Disinfection should be conducted to achieve
the appropriate CT value described in the SWTR
Guidance Manual for filtration and disinfection (18).
Other treated water goals, such as taste and odor levels
and pH, can also be established on a site-specific basis.
The change in attitude to support these goals often
doesn't occur until it is demonstrated that the plant, given
more intense process control, can consistently achieve a
very high quality finished water. However, once this is ex-
perienced, the administrators and operators are driven by
pride to maintain consistent, high quality treated water.
With this pride, comes the willingness of administrators to
provide adequate budgets and staffing to support op-
timum finished water quality.
Activities to implement any minor design changes iden-
tified as necessary during the CPE and confirmed by the
CCP facilitator should be initiated during the site visit.
Some design changes often require significant amounts
of time for approvals, delivery of parts or equipment, or
construction. It is necessary to obtain the desired
capability so that it is available for implementation during
the CCP effort.
Efforts to address administrative factors are also ap-
propriate to be implemented during the initial site visit. Ad-
ministrative changes such as increasing rates, changing
personnel, or long-range planning activities require sig-
nificant time and diplomacy to address. The sensitivity of
these issues may require that significant background infor-
mation be obtained before aggressive action is taken.
Offsite Activities
The CCP facilitator should provide a short letter sum-
marizing activities during the first site visit and include a
typed action-implementation plan. Any procedures or
process control sheets that were developed in coopera-
tion with the plant staff should also be formalized and
returned to the utility. Typing procedures and process
control sheets can help create an environment of "profes-
sionalism" concerning the CCP activities.
Phone calls should be made at least weekly to obtain
plant operating information and to make certain that ac-
45
-------
tion items are being accomplished in a satisfactory man-
ner. A return or intermediate site visit should be made
when plant operating conditions dictate or when process
control equipment (e.g., jar test apparatus, filter paper,
graduated cylinder, etc.) or minor design modifications
that were determined necessary for future COP activity
are available for implementation efforts,
Followup Site Visits
During intermediate site visits, followup training should be
presented to the plant staff on chemical feed calculations,
jar testing, and other procedures initiated during the initial
site visit. Repetitive training in this manner is effective in
transferring capability to the operating staff. Typically, the
concept of special studies ("Facilitator Tools", p. 34) is
also introduced at the first followup site visit and a
prioritized list of special studies is developed in coopera-
tion with the utility staff. During remaining site visits, the
facilitator should follow up on special study activities and
set additional direction as required.
The facilitator should present graphs depicting perfor-
mance improvement achieved during the CCP. This,
coupled with additional discussion on the necessity of
achieving continuous high quality water and praise
regarding improved performance obtained to date,
provides the operators with incentive to continue striving
to produce the highest quality water possible. During site
visits, discussions must also be held with administrators
informing them of progress and convincing them to con-
tinue support of optimum performance through adequate
budgeting and staffing. During the final site visit, the
results of the COP should be presented to administrators
and plant staff.
CCP RESULTS
The success of conducting CCP activities can be
measured by a variety of parameters, such as improved
operator capability, cost savings, improved maintenance,
etc. However, the true success of a CCP should be docu-
mented improved performance to the degree that the
plant has achieved an optimum finished water turbidity,
ideally less than 0.1 NTU but at a minimum in compliance
with the SWTR regulations. Given this objective, the
results of a successful effort can be easily depicted in
graphical form. Results from an actual CCP are
presented in Figure 3-8. As shown, plant performance
was inconsistent as depicted by the variations in finished
water turbidity. However, after CCP activities had been
implemented (end of June 1989), the treated water
quality remained consistent at about 0.1 NTU. It is
recommended that CCP results be presented in this for-
mat.
CCP Summary Report
A CCP summary report should be prepared and
presented to utility personnel upon completion of the
CCP. The objective is to summarize the conclusions and
document achievement of improved plant performance.
The report should be brief and outline activities that were
Figure 3-8. Finished water quality achieved during conduct of a CCP.
D
m
DC
Z5
I-
£E
LU
h-
<
5
0
LU
1
CQ
z
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
FUTURE REQUIREMENT
W XI
14-May-89 | 11-Jun-89 | 09^Jul-89 06-Aug-89
28-May-S9 25-Jun-89 23-Jul-39
46
-------
implemented to address the factors limiting plant perfor-
mance. Graphs documenting the improvement in plant
performance should also be presented, tf other benefits
were achieved these should also be documented. Eight
to twelve pages are typically sufficient for the text of the
report. A sample CCP report is shown in Appendix L.
Typical contents are:
• Introduction (Reasons for the CCP)
• CPE Results (Briefly summarize information from the
CPE report)
• CCP Significant Events (Chronological summary of ac-
tivities conducted)
• CCP Results (Graph of plant performance plus other
CCP benefits)
• Conclusions (Efforts required to maintain improved
performance)
At a minimum, the CCP report should be distributed to
plant administrators and key plant personnel. Further dis-
tribution of the report, for example to the design engineer
or regulatory agencies, depends on the circumstances of
the CCP, but should be done at the direction or with the
awareness of local administrators.
Case Study
A case study of a CCP is difficult to present because
many of the performance-limiting factors are addressed
through training, interpersonal relationships, weekly data
review, phone consultations, and other activities con-
ducted over a long period of time. These activities do not
lend themselves readily to an abbreviated discussion. An
overview of a CCP is presented based on the case study
of a CPE presented on pages 27-31.
Addressing Performance-Limiting Factors
The most serious performance-limiting factors identified
during the CPE were related to process control and
hydraulic loading rate. Therefore, the initial portion of the
CCP was directed at improving plant operations (process
control) and reducing plant flow rate.
1. Operation (Process Control)
• A process control sampling and testing schedule was
implemented and a daily data sheet was developed
to allow evaluation and control of plant processes.
On-the-job training was provided in process control
testing and interpretation including the use of jar tests
to determine correct coagulant doses.
• Procedures were developed for calibrating chemi-
cal feeders and calculating chemical dosages so
that chemical feed rates could be accurately ap-
plied. Coagulant and filter aid doses were changed
based on process control testing, which resulted in
a dramatic improvement in performance.
• Weekly phone calls and transmission of plant
operating data were initiated between the CCP
facilitator and plant staff. Operating targets were
discussed and process control changes were in-
itiated as necessary.
• Additional process control activities required more
operational attention, making it necessary to ad-
dress the issue of plant coverage.
• Special studies were conducted to determine the ef-
fect of reducing plant flow rate, eliminating negative
pressure from the filters, moving the alum application
point, and determining the source of excessive dis-
solved gases in the plant influent pipeline.
2. Administration
• The improved plant performance gained through
more intense process control was utilized to con-
vince administrators to allow plant operators to be
at the plant when it was in operation. The
administrators' familiarity with plant needs and their
ability to make appropriate decisions were in-
creased by descriptions of process requirements
and oral status reports. Administrators were also
kept informed of the special studies that indicated
minor modifications were necessary in the chemical
feed systems.
3. Design
• Plant flow rate was decreased by 50 percent to ad-
dress the poor solids capture of the upflow solids con-
tact sedimentation basin and to address the air binding
problem in the filters. A minor modification was made to
the filter effluent header to allow negative pressure to
be released from the bottom of the filter. These chan-
ges allowed the filters and sedimentation basins to
perform in an excellent manner.
• The filter rate of flow controllers was repaired in
order to eliminate rapid flow rate changes from
degrading filter performance.
• A polymer feed system was installed to allow addi-
tion of a floc/filter aid. The alum feed was changed
to a point just upstream from the plant control valve
to increase mixing.
• Major modifications that plant administrators had
planned, including construction of a presedimentation
basin and moving the intake structure, were avoided.
4. Maintenance
• Suggested maintenance forms were provided to
the plant superintendent. However, lack of a docu-
mented preventive maintenance program had not
been a significant performance-limiting problem
and, consequently, no additional emphasis was
placed on plant maintenance.
47
-------
Figure 3-9. Finished water quality achieved during the CCP case study.
z
£
Q
m
~c
D
1.4
1.3
1.2
1.1
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
1 Fit
J
I U
C
j!
i iitf
m
¦) n
I I 2J
~
A
FUTURE REQUIREMENT
3
0
02-Apr-89 12-May-B9 21-Jun-89 31-Jul-89 09-Sep-89 19-Oct09
28-Nov-89
Plant Performance
Plant performance was improved dramatically, as shown
in Figure 3-9. While plant performance improved after the
flow rate was reduced and the negative pressure on the
filters was eliminated, performance remained erratic until
process control, including chemical adjustments, was im-
plemented. After process control was initiated in June,
plant settled water and finished water turbidities
remained very consistent at about 1 to 2 and 0.1 to 0.2
NTU, respectively. This consistent performance was
achieved even though raw water turbidities varied widely.
Another indication of improved performance was that fil-
ter effluent turbidity following a backwash did not exceed
0.3 NTU and returned to 0.15 NTU within minutes after
backwash.
Summary
This example illustrates several important points of the
CCP approach and includes several problems and as-
sociated solutions that occur frequently during CCP im-
plementation. These are:
• The primary objective of a CCP is obtaining optimum
plant performance. A secondary objective can be mini-
mizing costs; however, this is often not possible if
plant staff time needs to be increased or if additional
coagulants and flocculant chemicals are needed.
• A Type 2 water treatment plant was brought into com-
pliance with the SWTR requirements without major
modifications. In fact, plans for major modifications
were abandoned.
• The degree of administrative support is sometimes dif-
ficult to assess but often becomes a major concern.
This was true when administrators were forced to
allow operators to spend additional time at the plant for
process control testing.
• Some potential performance-limiting factors identified
during a CPE are later found to be incorrect or less
significant when actually eliminating problems with a
CCP. This is especially true in evaluating the integrity
of filters, which were suspect in this example, but
proved to be a relatively minor problem.
PERSONNEL CAPABILITIES REQUIRED FOR
CONDUCTING CCPS
Persons responsible for conducting a CCP must have a
comprehensive understanding of water treatment, exten-
sive hands-on experience in water treatment operations,
and strong capabilities in personnel motivation. Com-
prehensive understanding of water treatment is neces-
sary because current state-of-the-art water treatment
leaves room for individual judgment in both design and
process control. For example, numerous unit processes
have been used in the past and are presently being ap-
plied, such as spiral flow, reactor type, lamella plate, tube
settlers, and solids contact sedimentation devices.
Numerous possibilities exist in terms of types, combina-
48
-------
tions, and dosages of coagulant, flocculant, and filler aid
chemicals. Also, the types, combinations, and dosages of
chemical aids may vary depending on the variations in
raw water supply and the unit process available at the
plant to treat the water. The CCP facilitator must be
familiar with all types of unit processes, raw water quality
characteristics, and chemical products available for suc-
cessful water treatment. In addition, those responsible for
implementing a CCP must have sufficient process ex-
perience to determine appropriate application of a
strategy to the personnel capabilities of the plant in ques-
tion. Leadership and motivational skills are required to fill
the multi-faceted "facilitator" role required of individuals
responsible for implementing a CCP.
Individuals who routinely work in the area of improving
water treatment plant performance likely will be best
qualified to be CCP facilitators. These people are typical-
ly engineers or operators who have focused their careers
on water treatment plant troubleshooting and have
gained experience in correcting deficiencies at plants of
various types. It is important that CCP facilitators have
experience in a variety of plants because the ability to
recognize true causes of limited performance is a skill
only developed through experience. Similarly, the suc-
cessful implementation of a cost-effective CCP is greatly
enhanced by experience.
By the very nature of the approach, the CCP facilitator
must often address improved operation, maintenance,
and minor design modifications with personnel already
responsible for these water treatment functions. A "worst
case situation" is one in which the plant staff is trying to
prove that "the facilitator can't make it work either." The
CCP facilitator must be able to deal with this personnel
issue in such a manner that allows all parties involved to
focus on the common goal of achieving plant performance.
A CCP facilitator must be able to conduct training in both
formal and on-the-job situations. Training capabilities
must also be developed so they are effective with both
operating as well as administrative personnel. When ad-
dressing process control limitations, training must be
geared to the specific capabilities of the process control
decision-makers. Some may be inexperienced; others
may have considerable experience and credentials. "Ad-
ministrative" training is often a matter of clearly providing
information to justify or support CCP activities. Although
many administrators are competent, some may not know
what their facilities require in terms of staffing, minor
modifications, or specific funding needs.
CCP facilitators can be either consultants, including State
and Federal personnel, or utility employees. However,
the desired "existing facility" focus of a facilitator must be
maintained, since a substantial construction cost can be
incurred if an inexperienced facilitator is not able to bring
a capable water treatment plant to the desired level of
performance. For example, a consultant, involved
primarily with facility design, may not have the operation-
al experience to utilize the capability of existing unit
processes to their fullest extent and may be partial
toward designing and constructing new processes.
If local administrators decide to conduct a CCP without
the services of outside personnel, they should recognize
that some inherent problems may exist. The individuals
implementing the CCP, for example, often find it difficult
to provide an unbiased assessment of the area in which
they normally work: operating personnel tend to look at
design and administration as problem areas; ad-
ministrators typically feel the operating personnel should
be able to do better with what they have; the engineer
who designed a facility is often reluctant to admit design
limitations, etc. These biases should be recognized and
discussed before personnel closely associated with the
plant initiate a CCP.
REFERENCES*
1. U.S. EPA. 1987. Public Notification Regulation Rule.
40 CFR, Part 141, Subpart D, Reporting, Public
Notification and Recordkeeping. October.
2. Hudson, H.E., Jr. Water Clarification Processes Practi-
cal Design and Evaluation. Van Nostrand Reinhold Co.
3. Singley, H.E. 1981. Coagulation control using jar
tests. In: Coagulation and Filtration: Back to Basics.
Seminar Proceedings, 1981 Annual Conference
AWWA, St. Louis, MO, p. 85. June.
4. Hudson, H.E. and J.E. Singley. 1974. Jar testing and
utilization of jar test data. In: Upgrading Existing
Water Treatment Plants. AWWA Seminar Proceed-
ings, VI-79. June.
5. U.S. EPA. 1990. EPA Summary Report: Optimizing
Water Treatment Plant Performance with the Com-
posite Correction Program. EPA 625/8-90/017. U.S.
EPA Center for Environmental Research Information.
March.
6. Renner, R.C., B.A. Hegg, and D.L. Fraser. 1989.
Demonstration of the Comprehensive Performance
Evaluation to Assess Montana Surface Water Treat-
ment Plants. Presented at the 4th Annual ASDWA
Conference, Tucson, Arizona. February.
7. Water Rates (M1). 1983. AWWA Reference Manual
Series. No. 30001. Denver, CO: AWWA.
8. Water Rates and Related Charges (M25). AWWA Refer-
ence Manual Series. No. 30026. Denver, CO: AWWA,
9. The Rate-Making Process: Going Beyond the Cost of
Service. 1986. AWWA Seminar Proceedings. No.
20001. Denver, CO: AWWA.
49
-------
10. Developing Water Rates, 1973. AWWA Seminar
Proceedings. No. 20124. Denver, CO: AWWA.
11. Water Rates: An Equitability Challenge. 1983. AWWA
Seminar Proceedings. No. 20172. Denver, CO: AWWA.
12. Process Applications, Inc. 1990. Summary Report -
Loma, Montana Water Treatment Plant Composite
Correction Program. Unpublished report. December.
13. Prendiville, P.W. 1984. Ozonation of the 900 cfs Los
Angeles Water Purification Plant. Presented at the
IOA Pan American Committee Conference, Montreal,
Canada. September.
14. Cleasby, J.L., M.M. Williamson, and E.R. Baumann.
1963. Effect of filtration rate on quality. Journal
AWWA. 55:869-878.
15. Personal communication with Dr. Jack L. Cleasby.
November 5,1990.
16. Hibler, C.P. and C.M. Hancock. Interpretation - Water
Filter Particulate Analysis. Fort Collins, CO: CH Diag-
nostic & Consulting Service, Inc.
17. Hibler, C.P. Protocol - Sampling Water for Detection
of Waterbome Particulates, Giardia, and Cryp-
tosporidium, Fort Collins, CO: CH Diagnostic & Con-
sulting Service, Inc.
18. U.S. EPA. 1989. Guidance Manual for Compliance
with the Filtration and Disinfection Requirements for
Public Water Systems Using Surface Water Sources.
NTIS No. PB-90148016. Washington, DC: U.S. EPA.
October.
*When an NTIS number is cited in a reference, that refer-
ence is available from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
(703) 487-4650
50
-------
CHAPTER 4
FINDINGS FROM FIELD WORK
INTRODUCTION
This chapter summarizes findings from the field activities
and draws conclusions concerning future efforts and
potential impacts of utilizing the CCP approach in water
treatment. Twenty-one CPEs and three CCPs completed
at surface-supplied water treatment plants located in six
states provide the basis for the handbook contents.
These field efforts focused on an assessment of
capability and implementation of corrective actions for
existing plants to meet the turbidity and disinfection re-
quirements of the SWTR without major modifications.
Further efforts, which include additional onsite activities,
are being conducted to allow refinement of the handbook
techniques.
Table 4-1 provides information on the plants that have
been evaluated. Ten of the plants were in Montana, three
each were in Maryland and West Virginia, two each were
in Ohio and Kentucky, and one was in Pennsylvania.
The plants had a wide range of peak operating flow rates,
but were generally serving small to medium-sized com-
munities. All used surface water for their raw water
source. Most of the plants utilized conventional unit
Table 4-1. Summary of Plants Where CPEs Have Been Conducted
UTILITY NO.
POPULATION
PEAK OPERATING FLOW
PROCESS TYPE
1
9,602
7.0 MGD
Lime Conventional/Softening1
2
5,000
2.2 MGD
Conventional
3
2,553
2.6 MGD
Conventional
4
240
.09 MGD
Conventional
5
3,075
3.0 MGD
Direct Filtration
6
5,000
4.0 MGD
Lime Conventional/Softening1
7
5,481
4.6 MGD
Conventional
e
200
0.4 MGD
Lime Conventional/Softening1
g
1,207
1.7 MGD
Direct Filtration
10
1,000
0.5 MGD
Conventional2
11
1,900
0.5 MGD
Conventional1
12
2,700
0.7 MGD
Conventional1
13
3,400
1.5 MGD
Conventional
14a6
2,000
0.5 MGD
Conventional
14be
•
0.B MGD
Conventional1
15
4,000
0.4 MGD
ConventionaP
16
50,000
7.2 MGD
Conventional4
17
1,500
0.6 MGD
Conventional3
18
1,000
0.3 MGD
Conventional
19
12,300
1.1 MGD
Conventional
20
400
0.1 MGD
Conventional2,5
21
3,300
4.0 MGD
Conventional
1 Equipped with reactor clarifier combining flocculation and sedimentation in one basin.
2Equipped with rotary arm upflow clarif ier combining ftocculation and sedimentation in one basin.
3Equipped with spiral flow flocculation/sedimentation basins.
^Equipped with absorption clarifiers.
5Equipped with automatic valveless gravity filters.
6Utility had two separate plants.
'Plants 14a and 14b serve a total of 2,000 people.
51
-------
4
processes consisting of rapid mix, flocculation, sedimen-
tation, filtration, and disinfection.
RESULTS OF COMPREHENSIVE
PERFORMANCE EVALUATIONS
General
This section summarizes the findings from the 21 CPEs.
Each CPE consisted of an assessment of the plant's per-
formance, an evaluation of the capabilities of the major
unit processes, and the identification and prioritization of
the factors limiting performance. Projections relative to
each plant's capability to comply with the turbidity and
disinfection requirements of the SWTR were made from
the CPE results.
Major Unit Process Capability
A summary of major unit process capability for the 21
utilities and 22 plants evaluated is shown in Table 4-2.
The unit process capability is expressed as Type 1, 2, or
3, using the definitions presented in Chapter 2 (see
Figure 2-1). A Type 1 or 2 rating indicates that the unit
processes are potentially adequate to consistently meet
performance requirements, whereas a Type 3 unit
process could not be expected to perform adequately.
The evaluation format utilized to determine unit process
type was (and still is) being developed during the conduct
of the CPEs. As such, only 12 plants are included in the
disinfection unit process results because disinfection as-
sessment criteria were modified significantly during the
CPEs. The first nine plants' disinfection systems were
evaluated based on providing a disinfection contact time
of 2 hours. The disinfection evaluation was later modified
to a CT based method to reflect the new criteria publish-
ed in the SWTR Guidance Manual (1).
As shown in Table 4-2, the flocculation, sedimentation,
and filtration unit processes were felt to have adequate
facilities to justify attempts to optimize the existing perfor-
mance. Only 2 of 17 flocculation and 2 of 20 sedimenta-
tion unit processes were judged to require major capital
improvements (e.g., received a Type 3 rating). The total
number of flocculation and sedimentation processes
does not total 22 because some of the plants were not
equipped with these facilities. It is interesting to note that
20 of 22 filters were rated Type 1 and were judged to
have the capability to satisfactorily treat water at current
peak instantaneous operating flow rates. Several filters
were found to require media replacement because of
damaged underdrains or support gravels; however,
media replacement was not judged to be a major con-
struction alternative.
Based on these findings, it was projected that 19 of the
22 existing plants could be brought into compliance with
the turbidity requirements of the SWTR without major
construction. This projection is especially encouraging
since only 6 of the 22 plants were achieving a turbidity of
0.5 or less, 95 percent of the time, based on data for the
12 months prior to each CPE.
Postdisinfection was evaluated at 13 facilities with
respect to their capability to achieve proposed CT values
as defined in the SWTR Guidance Manual (1). Three of
the 13 plants evaluated were projected to have postdisin-
fection systems adequate to achieve required CTs. The
primary deficiency was the limited contact time in clear-
wells that were typically designed to provide backwash
water storage or high service pump wet wells. The unbaf-
fled basins, which are normally operated on a fill and
draw basis, do not represent ideal conditions for disinfec-
tion. In many cases, baffling will not achieve the effective
contact time required.
It is noted that actual levels of disinfection required will be
established by the individual States. Therefore, these dis-
infection results may further evolve depending on the
regulations that are finally adopted.
Prechlorination may allow some plants to provide ade-
quate disinfection capability with existing facilities;
however, this practice may be limited because it enhan-
ces the formation of disinfection byproducts. In Plant 17,
inclusion of predisinfection allowed the required CT
values to be achieved. If only postchlorination were al-
lowed in projecting disinfection capability, the plant could
Table 4-2. Summary of Major Unit Process Evaluations
for Facilities Where CPEs Were Conducted
UNIT PROCESS TYPE
Plant
Post-
No. Flocculation
Sedimentation Filtration
Disinfection
1 NA 1
2 2 2
3 2 2
4 2 2
5 2 NA
6 NA 3
7 1 1
8 NA 2
9 NA NA
10 3 3
11 1 2
12 1 2
13 1 1
14a* 1 2
14b 1 1
15 1 1
16 NA 2
17 1 1
18 2 2
19 1 1
20 3 1
21 2 2
"The utility had two water treatment plants.
"Disinfection was not evaluated using CT criteria.
1
3
3
3
3
3
3
3
3
3
1
1
3
52
-------
only be operated at 10 percent of its peak operating flow.
Use of both pre- and postchlorination, however, would
allow the plant to be operated at more than double the
present peak operating flow rate and still be projected to
achieve the disinfection requirements of the SWTR.
Overall Factors Limiting Performance
Factors limiting performance were identified for each of
the 21 CPEs utilizing the list of 65 factors described in
this handbook. An average of nine factors was identified
at each plant. Each factor was also given a rating of A, B,
or C, depending on its impact on performance. Table 4-3
presents a combined ranking of the top 10 factors found
to limit performance. The ranking was determined by as-
signing a numerical value to each factor, depending on
whether it was an A, B, or C, as shown in Table 4-4. A
total number of points was then calculated for each fac-
tor, reflecting the number of plants where it was identified
and its degree of impact.
Individual plants, their overall high ranking is of major sig-
nificance in interpreting cumulative results. To consistent-
ly achieve high quality finished water and meet the
turbidity requirements of the SWTR will require optimiza-
tion of each unit process in the treatment scheme. Addi-
tionally, optimum performance requires timely
adjustments in response to changing raw water quality.
Plant staffs must perform regular process control testing
and make frequent process adjustments (e.g., change
chemical doses) to achieve optimum performance goals.
Essentially no process control testing was being prac-
ticed at 15 plants. At 14 plants, the operators generally
had problems applying their knowledge of water treat-
ment to the control of the treatment processes. While
they could discuss coagulation chemistry and filter opera-
tion, their operational practices did not demonstrate that
they could respond to changes in raw water quality and
operate their plant to achieve consistent high quality
Table 4-3. Overall Rating of Top 10 Factors Identified by 21 CPEs
NUMBER
NUMBER
RANK
FACTOR
OF POINTS
OF PLANTS
CATEGORY
1
Disinfection
41
15
Design
2
Process Control Testing
38
15
Operation
3
Application of Concepts
34
14
Operation
4
Process Flexibility
30
16
Design
5
Sedimentation
28
15
Design
6
Filtration
25
10
Design
7
Staff Number
22
10
Administration
8
Ftocculation
22
11
Design
9
Administrative Policies
17
8
Administration
10
Water Treatment Understanding
15
5
Operation
Table 4-4. Categories for Rating Performance-Limiting
Factors
A Factor Major Impact 3 Points
B Factor Lesser Impact 2 Points
C Factor Minor Impact 1 Point
The top ranking factor was disinfection, which cor-
responds to the major unit process evaluation results. As
noted, the adoption of final regulations by the States may
affect the ranking of this factor. The use of prechlorina-
tion and/or baffling of clearwells to improve disinfectant
contact time (e.g., minor modifications) may allow some
of these plants to provide required disinfection capability.
Despite the potential options to address this factor, some
plants may require major capital improvements, including
larger contact basins or a change in disinfectants to meet
the CT requirements.
Three of the top 10 factors were related to operations:
Number 2 - Process Control Testing, Number 3 - Applica-
tion of Concepts, and Number 10 - Water Treatment Un-
derstanding. Although identified separately at the
treated water. Lack of water treatment understanding
was identified at five plants. A lack of understanding
means that the operators did not have the basic
knowledge of water treatment, which would make suc-
cessful implementation of a process control program and
achieving acceptable treated water impossible.
The finding that operations severely limited performance,
coupled with the fact that 18 existing facilities were as-
sessed to have adequate major unit process capacity to
meet the turbidity removal requirements (see Table 4-2),
indicates that addressing operations factors could sig-
nificantly improve water treatment plant performance.
Based on the severe impact of the operational factors, it
was projected that 19 of 22 facilities could achieve com-
pliance with the SWTR if these factors were addressed in
conjunction with minor modifications and plant loading
adjustments. To date, three plants have been brought
into compliance using followup (i.e., CCP activities)
without major construction. The impact of proper opera-
tion has been described by others (2).
Half of the top 10 factors were related to the design of the
plant and its treatment processes. A lack of process
53
-------
flexibility was identified at 16 plants. These plants were
not usually equipped with the capability to add chemicals
at different points in the plant or operate processes in dif-
ferent configurations (e.g., series and parallel). Flow con-
trol capabilities to regulate plant influent flow, filtration
rates, and backwash rates were also often limited. Often
times, many of the flexibility limitations can be addressed
during a followup CCP using minor modifications.
While most sedimentation, filtration, and flocculation
processes were found to be of adequate size during the
major unit process evaluation, problems primarily related
to inlet baffling or equipment associated with these
processes made them a factor limiting performance.
Sedimentation processes were projected to be marginal
at 15 plants, mainly when treating high raw water tur-
bidities that occurred on a seasonal basis. Problems
such as air binding, backwash limitations, improperly
maintained rate of flow controllers, and possible failure of
the underdrain or support gravel contributed to filters
being identified as a factor at 10 plants. Flocculation
problems (11 plants) were usually related to marginal
volume, improper staging, and inoperative mechanical
equipment. Implementing minor modifications, reducing
peak operating flows, and improving process control
were projected to allow the sedimentation, filtration, and
flocculation factors to be addressed without major
modifications. If a CCP implemented at these facilities
proved unsuccessful, then a construction alternative
could be pursued. It was concluded that, despite the high
ranking for design factors, immediate construction of
major plant modifications was not indicated or warranted.
Top administrative factors were related to the number of
staff provided and the policies of those administrators
responsible for the plant. Ten of 22 plants had an inade-
quate number of operators. This was considered to be
critical with respect to the projected need for increased
levels of process control and monitoring required under
the SWTR, and for the need to have operating staff at the
plant when it is in operation. Plant administrators were
frequently not aware of plant requirements, did not seem
to understand the impact of their decisions on protecting
public health, and had maintained plant funding at levels
too low to support process control and staffing require-
ments. Administrators were generally more aware of the
quantity of finished water from their plant than the sig-
nificance of finished water quality. For example, most
were unaware of the impact on public health of even
short-term "excursions" from high quality treated water.
It is interesting to note that insufficient resources were
not found to be a significant factor limiting performance of
the small water plants evaluated despite the fact that lack
of resources is a widely publicized reason for noncom-
pliance of small systems. Insufficient funding was iden-
tified in only 1 of 21 CPEs. Numerous small utilities had
sizable capital reserve funds, and those that did not often
had water rates set at unreasonably low levels. It was
projected that resources could be made available to ad-
dress operations problems and minor design modifica-
tions that were identified. Significant time for training
would be required in any followup CCP to gain ad-
ministrative support for further development or realloca-
tion of resources to address identified factors.
Maintenance-related factors were not identified in the top
10. These factors were assessed as having a lesser or
minor impact relative to operations and administrative
factors. At two facilities, total neglect was apparent. In
both of these facilities administrative policies concerning
support for the integrity of the infrastructure were felt to
be the root cause of the neglect. It was also observed
that a lack of understanding of process objectives led
operators to abandon many of the automatic and/or
manual control systems provided. It was assessed that
an emphasis on optimizing performance of each unit
process would have led to an improved emphasis on
maintaining existing plant control features.
Plant-Specific Findings
Findings from the CPEs at individual plants are
presented in this section. Operation practices dramatical-
ly impacted performance at several plants. All of the
plants that operated intermittently or continuously for less
than 24 hours a day consistently started dirty filters.
Plant 6 bypassed the reactor clarifier during winter
months and switched to direct filtration, without the use of
any chemical coagulants, which significantly reduced the
filter's ability to remove turbidity and cysts. At Plant 19,
the operators were using backwash flow rates of one-half
of design because of an administrator's order to reduce
energy costs. Directing all of the flow through one filter
while washing the remaining filter and operating the plant
unattended overnight were also additional undesirable
operational practices found at Plant 19. Water was cas-
cading onto the filter media at Plant 12 because rate con-
trol valves were inoperable and thus could not be used to
keep the filters flooded. This contributed to short-circuit-
ing and resulted in high turbidities (e.g., 6 NTUs) in the
clearwell. At Plant 20, completion of all operation and
maintenance activities was accomplished by one part-
time operator, even though the plant is on-line 24 hours a
day, 365 days a year.
The comprehensive nature of the CPEs allowed iden-
tification of more subtle performance impacting practices.
Plant 20 was providing unfiltered water to several cus-
tomers and discharging sludges into a drainage ditch ad-
jacent to the plant. No permit had been issued by the
State. Plants 3 and 10 were discharging sludges and
backwash water directly to streams in direct violation of
their operating permits. One of the filters at Plant 21 and
at Plant 2 was found to be "blown," providing a significant
potential for the passage of cysts into the finished water
that was, otherwise, of excellent quality. At Plants 4 and
54
-------
20, inadequate backwashing capabilities were found that
had caused the formation of significant numbers of mud-
balls in the filters. While achieving good performance
during the CPE, sludge deposits in the finished water
storage basins used for backwashing indicated that the
filters were not providing a consistent finished water
quality.
The involvement of the plants' administrators in the CPEs
made the evaluations more effective in redefining local
priorities. It was determined, through interviewing ad-
ministrators, that they often had not been informed of pre-
vious inspection results and, as such, had not been
supportive of implementing findings. The CPE format re-
quires administrators to be involved during the evaluation
and to be informed of the results during an exit meeting.
A CPE at Plant 13 found that administrators had agreed
to supply low-cost water to two new customers that would
use one-third of the plant's existing treatment capacity. It
was projected that this would cause revenue shortfalls,
strain existing plant capacity, and lead to deterioration of
plant performance. When presented with this information,
the administrators decided to investigate conducting a
rate study and to attempt renegotiation of the agreements
with the new customers. Followup conversations with
Plants 10, 12, 13, and 15 indicated that the CPE report
was used by their administrators as a basis to implement
changes.
The exit meeting was regarded as an especially valuable
part of the CPE since it assured that the administrators
were aware of their role and responsibility in supplying
good quality treated water and protecting the public's
health. Administrators informed of performance problems
during the exit meeting changed their priorities regarding
water treatment improvements and policies. At Plant 19,
an administrator said the CPE had changed his perspec-
tive on water quality and plant needs. Plant 12's ad-
ministrators, during the exit meeting, made a commitment
to correct the severe performance problems at the plant.
The observed impact of CPE results on priorities of ad-
ministrators may indicate a potential inability or a reluc-
tance of existing plant staffs to solicit needed support
from administrators. It may also indicate the reluctance of
administrators to listen to the plant staff without "outside"
pressure.
Some of the CPE findings were identified during the plant
tour, but most had to be identified or verified during inter-
views and through special studies. Interviews were espe-
cially effective in establishing an operator's capabilities
and in assessing an administrator's impact on plant per-
formance, Special studies played an important role in
finding performance problems not apparent in plant
records. An on-line continuous recording turbidimeter
was used to measure the effluent turbidity of one filter
during the CPE. The turbidimeter was installed after the
plant tour on the first day, allowing the recording of the fil-
ter effluent turbidity over the remaining days of the CPE.
These results indicated filter performance under routine
operation, during plant startup, during filter rate control
adjustments, and during backwash cycles. During initial
CPEs, a continuous turbidimeter was not available and
only grab samples of filter effluent could be collected.
Utilizing special study results, performance during the
CPEs was assessed to be worse than reported on
monthly State monitoring reports at 14 of 22 plants. In
several cases, plant finished water quality during the
CPE was so poor that the State threatened to institute a
boil order unless immediate improvements were made.
At Plant 17, a finished water turbidity of 0.0 NTU,
measured on a broken turbidimeter, had been reported
for the previous 18 months, yet effluent turbidity was
found to routinely exceed 1.0 NTU. These findings indi-
cate that the present requirements of sampling turbidity
from the clearwell on a daily basis do not necessarily
reflect actual plant finished water quality. Continuous
measurement and recording of turbidity from each filter is
considered essential to provide the operators enough in-
formation to minimize any excursions in treated water tur-
bidities.
Turbidity versus time profiles of filter effluent provided
valuable insight into plant performance. Plant 2 had
shown no turbidity violations over the previous 12
months, but monitoring of a filter before and after back-
wash, as shown in Figure 4-1, revealed a turbidity
breakthrough of 5.8 NTU. This special study also found a
delay in the decision to backwash, which resulted in a
significant increase in filtered water turbidity just prior to
initiating the backwash cycle. These spikes were con-
sidered a significant performance problem because even
relatively small, short-term turbidity spikes can allow the
passage of significant numbers of cysts through a filter
and can thus impact public health.
Plant 15 reported the finished water turbidities shown in
Figure 4-2, which indicated compliance with present as
well as future requirements of the SWTR. A turbidity ver-
sus time profile for one of the filters after backwash,
shown in Figure 4-3, found a turbidity spike of 24 NTU.
Problems with a chemical feed pump were also dis-
covered when the turbidity continued above 1.0 NTU for
almost 2 hours after backwash. Monitoring performance
once a day, which was the normal practice, would not
have allowed the performance problems to be identified
in a timely fashion. Following the CPE, Plant 15 began
monitoring performance every hour, closely watching tur-
bidity spikes after backwash and using their filter-to-
waste capabilities. Finished water turbidities are still
typically less than 0,5 NTU, and peak turbidities after
backwash are controlled to 0.8 NTU.
A review of finished water turbidities for a 1-year period
at Plant 12, shown in Figure 4-4, indicated a consistent
water quality that rarely exceeded 1.0 NTU. Clearwell tur-
55
-------
Figure 4-1. Plant 2 turbidity profile before and after backwash.
D
H
Z
£
g
m
~:
D
Z
LU
D
LL
LU
~:
LU
FILTER BACKWASH -
:
; j
: 1
¦'
I i
' !
•
i
i
\
\
i
\
. \-h-~ ~
i
\
\
\
\
/' :
\
i
,..o
\
£
\
.... _ -
~ I I 1 T — f—
1*1
b
100 200 300
MINUTES AFTER START OF SPECIAL STUDY
Figure 4-2. Finished water turbidity versus time.
¦ ¦¦ I ¦ ¦ ¦ ¦ I I ¦ M | ¦ ¦ ¦ 1 I
00
CD
X
+>
TJ
_Q
L.
3
ru
(3
1 i i " |
> l>
M>
E> Wfr
400
Present
1 1 Requirement
t$> l> B
i> > ®t> »¦> > >ia> > ts«t>
Future
Requ i rement
JRN FEB MRR HPR MRY JUN JUL RUG SEP OCT NOV DEC JRN90 FEB
Days
56
-------
Figure 4-3. Filter effluent turbidity versus time, 105 minutes after backwash.
oj
h-
Z
in
>s
¦p
_Q
c_
3
H
in
Present
Requ irement
50
80
70
100 110
0
10
20
30
40
90
Mi nutes
Figure 4-4. Finished water turbidity versus time for 1-year period.
in
OJ
I-
•Z.
>s m
+»
"O
XI
L.
3
I-
Present
Requ i rement
fe
Future
Requ i rement
SEP88 OCT NOV DEC JANS9 FEB MRR APR MHY JUN JUL RUG SEP OCT
Days
57
-------
bidities of 6 NTU, however, were measured over a 3-hour
period during the CPE. As shown in Figure 4-5, a tur-
bidity spike of 38 NTU was also measured from one of
the filters following backwash. Prior to these special
studies, the operators had been measuring turbidities in-
appropriately, utilizing a spectrophotometer.
Control of filtration rates during routine operation and
during backwashing cycles was found to play a key role
in preventing turbidity spikes and the potential for pas-
sage of cysts. Filter rate controllers were malfunctioning
at Plant 2, resulting in the filter effluent valves opening
and closing every few seconds, with a subsequent
change in filtration rate from Q. to 1,000 gpm. Figure 4-6
shows the variations in the filter effluent turbidities. The
variations in turbidity indicate that numerous particles
previously filtered were now being washed through the fil-
ter to the clearwell. The plant staff knew that the valve
"jumped around," but had no idea that it was affecting fil-
ter performance.
When a filter at Plant 2 was removed from service for
backwashing, the entire plant flow was directed instan-
taneously to the remaining filter. A plot of the effluent tur-
bidities for the remaining operating filter, shown in Figure
4-7, indicates that this also caused a severe turbidity
breakthrough (e.g., 46 NTU) as the fitter flow rate was
quickly "bumped" by the rapid increase in filter loading.
Additional examples of improper flow control relative to
filter operation were observed. At Plant 12, water was al-
lowed to drop from the influent troughs onto the filter
media, as shown in Figure 4-8. The operators had no
idea that this practice had a negative impact on treated
water quality or that the filters were supposed to be
flooded above the media. Following the CPE, funds were
committed for repairs to the rate control valves and addi-
tional staff time was allocated to assure that the filters
were always flooded. The staff at Plant 19 would abruptly
change the filter effluent valve several times a day to
control water levels in the filters. During backwash of a fil-
ter at this plant, all of the plant flow was directed through
one of the plant's four filters, even though one of the fil-
ters was backwashed and available on standby basis.
Filtered water turbidities can also increase significantly at
plants that start dirty filters. Figure 4-9 shows the impact
of this practice on filter effluent at Plant 8.
Sampling on a daily or even an every-4-hour basis was
shown to be inadequate to assure consistent water
quality. Many of the significant performance breakdowns
were found to happen on a short-term periodic basis
Figure 4-5. Filter effluent turbidity versus time after backwash.
LH
m
h-
Z 1/1
w ™
13
^ ru
T3
in
-Q
3
I-
in
Present
¦Rsqu i rement
0 3 G 9 12 15 10 21 24 27 30
T i me (m i n )
58
-------
Figure 4-6. Turbidity profile showing the impact of a malfunctioning filter rate controller at Plant 2.
o
m
a.
3
LU
a.
0.6
0.5
0.4
0.3
0.2
0.1
J !_
FUTURE REQUIREMENT
7\
•e a
/
.j I
_i .. i..
2 3 4 5 6 7 8
MINUTES AFTER START OF SPECIAL STUDY
_i..
10
Figure 4-7. Turbidity profile showing the impact of "bumping" a filter with total flow during backwash of other filter at
Plant 2.
D
m
cr
3
OTHER FILTER BACKWASHED
PRESENT REQUIREMENT
¦—-c?^
-i
-4-
\
100 200 300
MINUTES AFTER START OF SPECIAL STUDY
400
59
-------
Figure 4-8. Performance Impacting practice of water falling from influent troughs onto the filter media.
during operations such as backwashing, changing plant Several turbidity spikes were seen on both filters. During
flow rates suddenly, or returning a backwashed filter to backwash, a spike was seen in the opposite filter be-
service. The only way these episodes can be minimized cause all of the plant flow was passing through three in-
is to be aware that they are occurring by continuously stead of four filters. Spikes in turbidity from these filters
measuring and recording turbidity from each filter in a immediately after each was backwashed were also ob-
plant. These on-line continuous recording turbidimeters served. Filter 3 also experienced a significant spike when
were used at several plants to reveal turbidity fluctuations plant flow was increased during the night to compensate
and help identify their causes. Figure 4-10 shows the tur- for a line break in the distribution system. A malfunction-
bidity from one of the filters at Plant 19 over a 14-hour ing automatic rate of flow controller was also found to be
period. Not only was the filter producing a finished water causing the erratic turbidity fluctuations in Filter 3 during
with turbidities greater than 1.0 NTU, many spikes in tur- periods of otherwise steady performance. Once the plant
bidity were also measured. This was caused by fluctuat- administrators observed these performance problems
ing flow through the filter caused by improperly operating and the value of the continuous recording turbidimeters in
rate of flow controllers. The need for continuous monitor- identifying them, units were ordered for each of the four
ing of individual filters at this plant was also shown. Tur- filters. The rate of flow controller on Filter 3 was also im-
bidity measurements on the other filters showed that they mediately placed in manual mode. Following the CPE,
were producing water of less than 0.1 NTU. Monitoring changes were also made in backwash procedures so that
only a single filter or a single measurement of finished plant flow was reduced such that the remaining filters
water from the clearwell would not have provided any in- would not receive increased hydraulic loading. Con-
dication of the tremendous potential for passage of cysts tinuous monitoring of individual filters assures consistent
through this individual filter, the potential problems with performance by allowing the operators to observe how
flow control, or the obvious need to backwash this filter. their operation procedures impact water quality.
At Plant 16, a continuous monitoring turbidimeter on the A key finding from the CPEs is that treatment process
combined effluent from all four filters, along with hourly capacity at many small water treatment plants can be in-
monitoring of the individual filters by the operators, indi- creased through modified operation practices. Many of
caled that finished water quality was well within com- these plants are typically sized to allow 8 or 12 hours-
pliance with the SWTR turbidity requirements. During the per-day operation. This provides a great deal of flexibility
CPE, continuous turbidity monitoring of two of the four fil- since unit process limitations can often be addressed by
ters was conducted, as shown in Figure 4-11. These operating at lower flow rates for a longer period of time,
measurements were taken over the same period of time. For example, at Plant 8 it was discovered that the plant
60
-------
Figure 4-9. Turbidity profile showing the detrimental impact of dirty filter startup at Plant 8.
6
5
4
3
2
PRESENT REQUIREMENT
1
FUTURE REQUIREMENT
0
10
12
14
18
20
0
2
6
16
4
8
MINUTES AFTER START OF SPECIAL STUDY
Figure 4-10, Filter "C" turbidity during CPE.
k/ftr /is'/ii&ur P
I f A.V7£T
\ /m * t&f
Tfatm.
61
-------
Figure 4-11. Filter Nos. 3 and 4 effluent turbidity versus time.
i'AAi
writ
Filter 4
o*
II
l«^w/
was being operated at its 250 gpm capacity for only
several hours each day, even when turbidity levels in the
river exceeded the capability of the plant. It was projected
that reducing the plant flow to 125 gpm and operating for
up to 12 hours would allow the plant to provide the re-
quired finished water turbidity despite variations in raw
water quality. At Plant 5, reducing the plant flow from
2,100 gpm to 1,100 gpm allowed a severe filter air bind-
ing problem to be relieved, resulting in improved perfor-
mance and reliability for the plant. In both cases, water
demands could still be met.
Process control was assessed to be adequate at only 1
of the 22 plants. For the remaining plants, limited process
control testing was routinely completed with essentially
no interpretation of the results to allow proper process
adjustments. Little understanding of coagulation
chemistry was found to exist. As such, changes in
chemical feed rates corresponding to raw water quality
changes were either not completed or were changed
based on "experience." None of the plants with minimal
process control were attempting to optimize sedimenta-
tion basin performance. Plants 10, 12, 13, 15, and 19
were feeding alum and lime at the same point with no
consideration of the fact that lime could be raising the pH
out of the optimum range for alum coagulation. During a
check of the alum feed rates at Plants 8 and 10, the dose
was found to be twice what the operator reported was
being dosed. Changes in flow rate were made at Plant 2
without adjusting chemical feed rates, which led to
degraded finished water quality.
Administrators were found to have a significant impact on
the quality of water supplied to the community. At Plant
17, administrators had influenced the day-to-day opera-
tion of the plant and prevented the operators from obtain-
ing any training. Over many years, this same
administration had maintained low water rates, com-
pleted no long-range planning, and only reacted to crisis
situations. Water quality problems ultimately resulted in
public and State pressure, to which the administrators
responded with piecemeal spending, that brought the
system to near bankruptcy. Plant administrators at Plant
19 directed the operators to limit backwashing to reduce
energy costs. Budgets for this plant were developed so
that only low-cost, low-priority items were purchased for
the plant regardless of need. The planning and policies of
the administrators ignored the reeds of the plant, allow-
ing it to deteriorate. Staff requirements for the plant were
ignored, with three persons expected to provide 24-hour
operation. Administrators at Plant 13 failed to provide an
adequate organizational structure at the plant, with no su-
perintendent or manager position identified. This
provided a disjointed approach to operation and poor
staff communications that did not allow response to
process control changes and water quality problems. At
Plant 12, administrators had ignored evidence of water
quality problems (e.g., schools closed because of dirty
water) and allowed the plant to deteriorate while directing
their resources to a major reservoir project and exten-
sions to the distribution system. At none of these plants
were these decisions made with wanton disregard of
water quality. These administrators, generally, did not un-
62
-------
derstand their roles and responsibilities in providing good
treated water quality and protecting the public's health.
Followup Results
Followup phone calls were made to 12 of the 21 utilities
where CPEs were conducted to determine what effect
the CPEs had on the utilities. Overall, the CPEs provided
direction to the communities and helped them set
priorities with respect to the needs of their plants. At
facilities where performance was grossly out of line, con-
duct of the CPE and partial followup by local officials
were able to result in some improvement in performance.
It is projected that continuous compliance with the SWTR
would require comprehensive foliowup (i.e., address all
factors limiting performance) and plant-specific training
for operators and administrators.
Typically, attempts had been made to correct design-re-
lated factors. Administrative or operations-related
problems had often not been addressed. Since factors
related to process control testing and operator application
of concepts were high ranking factors at most of the
plants evaluated, these factors must be addressed if con-
tinuous compliance is to be achieved. An outside
facilitator will probably be required to assist utilities in cor-
recting personnel-related factors.
State Impacts
Overall reactions to the CPEs by the State personnel
who participated in the evaluations were favorable. They
considered CPEs a valid activity at all plants, especially
those with identified or suspected performance problems.
The evaluation also had a broader perspective and was
more comprehensive than other inspections or sanitary
surveys normally completed at the plants. State person-
nel thought the performance focus of the evaluation was
important.
It was found that State regulatory agency involvement
was essential for successful implementation of the CCP
approach in improving small water plant performance. In
several cases, regulatory pressure had to be applied to
ensure that changes in treatment practices were made.
At Plant 6, a boil order was initiated after State officials,
during a followup inspection to the CPE, noted high tur-
bidity water in the distribution system. The plant staff had
ignored a performance-limiting practice identified during
the CPE evaluation. At Plant 2, the State required the
plant staff to increase process control testing to a fre-
quency of every 4 hours until water quality was improved,
with the warning that a boil order would be initiated if the
finished water quality wasnl improved within several
days. At Plant 4, State drinking water personnel informed
the board that they needed to purchase process control
testing equipment necessary for followup technical assis-
tance and needed to become involved in a CCP or the
State would resort to stricter measures, possibly legal ac-
tion, to ensure compliance.
Other significant State impacts were documented. Nearly
all of the CPEs resulted in significant findings that had
not been identified in previous inspections. Exit meetings
with the administrators were thought to be one of the
major advantages of the CPE over other surveys and in-
spections. Several of the State personnel began to incor-
porate some of the special study procedures into their
regular inspections.
State personnel in ail states where CPEs were conducted
reported that the approach had several advantages for
their State programs such as providing a basis for perfor-
mance improvement activities, reviewing funding
priorities, improving staff morale, and providing a basis
for establishing regulatory and training priorities.
However, a frequent concern was expressed regarding
the labor intensity associated with the conduct of a CPE
and the potential that this had to interfere with existing
State and EPA water program requirements. To achieve
the CPE benefits, it is necessary to "institutionalize" the
program such that it is compatible with existing and newly
required State program activities. Montana is the only
state to date to initiate activities to try and make the CPE
an integral part of their program activities.
It is important to note that if the full benefits of the CPE
effort are to be realized, the overall approach will have to
be implemented. It has been observed that piecemeal im-
plementation of program elements exclude the com-
prehensive aspect of the evaluation, and significant
performance-limiting factors have been overlooked. In
fact, CPEs conducted at plants where recent sanitary
surveys had been completed showed significant differen-
ces in findings and, thus, necessary corrective actions.
The sanitary surveys were observed to exclude ad-
ministrative evaluations, portions of the performance as-
sessment steps, and some of the detailed process
control evaluations.
RESULTS OF COMPOSITE CORRECTION
PROGRAM IMPLEMENTATION
CCPs were implemented at three facilities to determine if,
in fact, plant performance could be improved without
major capital expenditures. A summary of these efforts is
presented below.
Plant 5
A CPE was conducted August 22 to 25, 1988, at Plant 5.
The plant is a direct filtration facility constructed in 1978.
Treatment includes coagulant chemical feed (alum and
cationic polymer), flocculation in a reaction basin, non-
ionic polymer filter aid feed, filtration through four dual
media filters, postchlorination, and gravity flow from the
plant to storage and distribution. Raw water is supplied
from a multiple use lake. Raw water quality is generally
good in winter months, with turbidities in the 5 to 10 NTU
range, but prevailing westerly winds often stir up sedi-
63
-------
ments in the relatively shallow lake in other seasons,
leading to turbidities as high as 50 to 280 NTU.
A review of operating data for the previous year revealed
that the plant was generally producing water of less than
1.0 NTU, but monthly samples would not meet 0.5 NTU
95 percent of the time. A special study conducted during
the CPE to determine the turbidities before and after
backwashing indicated that filter effluent turbidities in-
creased to over 3.2 NTU and did not drop below 1.0 NTU
for over 2 hours.
The performance potential graph developed during the
evaluation projected that the 3.0 MGD facility would have
to be derated to 1.5 MGD because of severe air binding
within the filter. This problem was exaggerated by the
design of the filter effluent header, which allowed the for-
mation of negative pressure in the filter underdrains. A
short detention time in the reactor/flocculation basin
resulted in a projected capacity less than design. A
longer time was felt to be necessary because of the cold
water during winter months.
The CPE report recommended that a followup CCP be
conducted because the identified top-ranking factors
were process control-related and it was felt that operator
training, conducted as a portion of a CCP, would improve
plant performance. It was concluded that the plant could
Figure 4-12. Finished water turbidity versus time for Plant 5.
0.9
0.8
0.7
FUTURE REQUIREMENT
0.4
T
02-Apr-89 12-May-89 21-Jun 89 31-Jul-B9 09-Sop 89 19-Oct-89 2B-NOV-B9
be operated at a lower flow rate during the conduct of the
CCP to address the design-related limitations of the fil-
ters and reactor basin. The reduction in plant How rate
was possible because the historical peak day demand
was only about 1.5 MGD.
Significant improvement in plant performance was
achieved during the conduct of the CCP. This is depicted
graphically in Figure 4-12. It is noted that while plant
operation improved after reducing the plant flow rate and
eliminating the negative pressure on the filter bottoms in
April, performance remained erratic until process control,
including chemical adjustments, was implemented in
July. After July 1989, plant finished water turbidities
remained very consistent at about 0.1 to 0.2 NTU through
the duration of the project. This consistent performance
was achieved even though raw water turbidities, shown
in Figure 4-13, varied widely. Plant finished water quality
remained below 0.3 NTU even when the raw water tur-
bidities reached 70 NTU, because the operating staff
consistently monitored varying raw water quality and
responded by changing chemical feed rates. The plant
performance is especially impressive since influent tur-
bidities frequently exceeded values thought to be
treatable with direct filtration (e.g., 50 NTU). Another in-
dication of improved performance was that filter effluent
64
-------
Figure 4-13. Raw water turbidity versus time for Plant 5.
80
70 -
60 -
„ 50 -
3
i-
z
£ 40 -
Q
CO
§ 30 -
t-
20
10
o -
02-
~ D
-7 n-~ te ..j
it
m
f
7 S ill ^
i o I IIIHM r..*;
mi,
j i M j rWi'f
^4J M inT 0) UtL?!1 1
I lit 'i ^ i
(1 i Bi '
a
Be
E
I M M
I ! | J !
i! i i $1
oft
i±j
y
¦v yffil-
fc
Apr
12-May
21-Jun
31 - Jul
09-Sep
19-Oct
28-Nov
turbidity following a backwash did not exceed 0.3 NTU
and returned to 0.15 NTU within minutes after the wash.
The CCP proved that Plant 5 could achieve compliance
with SWTR turbidity requirements without major capital
improvements. City administrators had planned on
spending an estimated one million dollars on construction
of sedimentation basin facilities and related improve-
ments. After the CCP, they decided to delay any con-
struction until water demands required the plant to be
operated at higher rates. The plant staff developed in-
creased confidence that excellent quality water could be
produced despite high raw water turbidities, and they
developed a level of pride that did not allow them to ac-
cept marginal finished water quality.
Plant 1
At Plant 1, performance based on finished water turbidity
was within existing standards, but the performance of the
reactor clarifiers was not optimum. Additionally, many of
the factors identified In the CPE were process control-re-
lated. It was felt that operator training, conducted as a
portion of a CCP, could be beneficial for process stability;
therefore, a CCP was initiated in January 1989.
Significant improvement in plant performance was
achieved due largely to expanded process control efforts
for the reactor clarifiers. Initial monitoring efforts revealed
problems with clarifier solids control. Each of the two
claritiers was taken out of service and several feet ot
anaerobic lime sludge that had accumulated in the basins
was removed. This activity was completed in May 1989.
Figure 4-14 shows the finished water turbidity from
Basins 1 and 2 from the time the basins were cleaned
until the CCP efforts were concluded in August 1989,
The basins' settled water turbidities gradually improved
and stabilized at 1 to 2 NTU. Another important aspect in-
dicated in Figure 4-14 was the fact that equal perfor-
mance was obtained from both basins. Controlled flow
splitting, equalized chemical doses to each basin, and
shutting off a well that was felt to be contributing a dis-
proportionate amount of flow to Basin 2 allowed this con-
sistent performance to be achieved. Stable performance
from the reactor clarifiers was achieved despite variable
influent turbidities to the basins from the presedimenta-
tion pond, as shown in Figure 4-15.
Most important, the improved reactor clarifier perfor-
mance "carried over to improve the consistency of tur-
bidity removal by the filters. Figure 4-16 shows the
overall plant finished water turbidity, which stabilized at
less than 0.2 NTU since the end of June 1989, which
coincided with stable performance from the contact
clarifiers. The improved performance was achieved
despite an increase in treated water volume and a
65
-------
Figure 4-14. Settled water turbidity versus time from the reactor clarffiers at Plant 1.
3
f-
2
>
Q
CD
oc
3
Z
LU
ID
LL
LU
3
5
w
z
w
<
m
12
11
10
9
8
7
6
5
4
3
2
1
0
14-May-89| 11-Jijn-89 | 09-Jul-89 | 06-Aug-89
28-May-89 25-Jun-89 23-Jul-89
n BASIN »2
BASIN #1
Figure 4-15. Effluent turbidity versus time from the presedimentation pond for Plant 1.
Q
a
oc
3
Z
LU
3
Z
to
<
CD
Q
LLI
CO
LU
cc
D_
14-May-89 j 11-Jun-89 I 09-Jul-89 | 06-Aug-89
28-May-89 25-JU1-89 23-Jul-89
66
-------
Figure 4-16. Finished water turbidity versus time for Plant 1.
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
J.
FUTURE REQUIREMENT
*
A 11
[H ^ ; J
Is* 9 ^
14-May-89 11-Jun-89 | 09-Jul-89 | 06-Aug-89
28-May-89 25-Jun-89 23-Jul-89
gradual increase in turbidities from the presedimentation
basin during the last month of the CCP.
The CCP resulted in dramatic improvement of plant per-
formance without major capital improvements. Turbidity
removal in the reactor clarifiers was improved and stabi-
lized, and the chemical requirements were minimized. A
combination of process control and monitoring, coupled
with several major process adjustments, allowed this im-
provement to occur.
Plant 8
At Plant 8, plant treated water quality exceeded the
proposed finished water turbidity level of 0.5 NTU on a
frequent basis. Performance assessment evaluations
conducted during the CPE indicated that filter effluent tur-
bidity following startup of a dirty filter (a common prac-
tice), immediately increased to over 5 NTU, and then
gradually decreased to about 1.5 NTU after 20 minutes.
Turbidity after the backwash increased immediately to a
peak value of 13.5 NTU. About 75 minutes after the filter
backwash, the effluent turbidity decreased to the 0.5 NTU
level.
A performance potential graph projected that the plant
could treat approximately 225 gpm when influent turbidity
remained below 500 NTU. This capacity was slightly less
than the present peak instantaneous operating flow of
250 gpm; however, the plant was only operated several
hours each day. It was recommended that a followup
CCP be conducted because the top ranked factors iden-
tified were process control-related and it was felt that
operator training would improve plant performance. It
was also concluded that the plant could be operated at a
lower flow rate to address the design-related limitations.
Significant improvement in treated water quality from the
sedimentation basin and filter was achieved, as shown in
Figures 4-17 and 4-18. During the initial 2 months of the
CCP (February and March), high effluent turbidity levels
existed from both the solids contact clarifier and the filter.
Effluent turbidity from the solids contact clarifier ranged
between 5 and 60 NTU, and effluent turbidity from the fil-
ter ranged between 0.4 and 1.8 NTU. During this same
time, raw water turbidity varied from 20 to 160 NTU (see
Figure 4-19). In the middle of this period, the plant was
taken out of service tor 5 days for cleaning, inspection,
and painting. Approximately 4 weeks were required to
reestablish a measurable sludge concentration in the
solids contact sedimentation basin after it was returned to
service. Process control procedures were developed to
optimize coagulant feed and to control the sludge con-
centration in the solids contact unit. Beginning in April,
consistent operational procedures resulted in improved
solids contact clarifier and filter performance. Clarifier ef-
fluent turbidity typically remained at or below 2 NTU
during the remainder of the CCP. Treated water turbidity
67
-------
Figure 4-17. Settled water turbidity versus time for Plant 8.
30
28
26
24
22
20
a is
b 16
i 14
cr
? 12
10
8
6
4
2
0
12-Feb 14-Mar 13-Apr 13-May 12-Jun 12-Jul 11-Aug 10-Sep
varied between 0.3 to 0.5 NTU between April and
August, but remained at about 0.3 NTU during Septem-
ber.
Four specific high turbidity events occurred in the raw
water during the summer on May 25, June 21, July 6,
and August 20. The operator was stow to respond to
these changes because he was not at the plant when
they occurred. When aware of the dramatic changes in
raw water quality, the operator responded by shutting the
plant down. However, when the plant was returned to
service on the following day turbidities were still slightly
elevated. Insufficient training had taken place for the
operator to optimize chemical feed adjustments;
however, coagulant doses were adjusted sufficiently
during these events to keep treated water turbidities less
than 0.7 NTU.
In another incident, on July 9, the alum feeder broke
down and a higher rate feeder was placed in service. Al-
though the operator reduced the feed rate to the lowest
level, the equipment change still resulted in an overfeed
of alum. Sedimentation basin performance degraded
dramatically on July 10, as evidenced by an increase in
clarifier effluent turbidity to 30 NTU and an increase in
treated water turbidity to 0.6 NTU. Plant performance
returned to normal following the repair of the primary
alum feeder.
Implementation of the CCP at Plant 8 demonstrated that
the plant could achieve compliance with SWTR turbidity
requirements without major capital improvements. The
results from the daily process control testing were used
successfully to control the sludge mass in the solids con-
tact clarifier and, to some degree, to control the alum
feed rate. These efforts improved the plant's perfor-
mance, as evidenced by treated water turbidities
decreasing from as high as 5 NTU prior to the CCP to the
current 0.3 to 0.5 NTU range.
The results of the CCP also emphasized the importance
of process control and adequate plant coverage during
high turbidity events. All of the spikes in treated water tur-
bidity that occurred during the summer could have been
avoided through proper process control adjustments.
These adjustments were not made because the operator
was not available to detect the problems and implement
the changes.
Factors limiting performance still exist at Plant 8 and are
being addressed during the ongoing CCP. It is projected
that an additional 6 months of assistance will probably be
necessary to address plant coverage and staffing issues,
68
-------
Figure 4-18. Finished water turbidity versus time for Plant 8.
c
>-
h-
Q
(~
q:
D
I-
12-Feb 14-r.ar 13-Apr 13-Moy 12-Jun 12-Jul 11-Aug 10-5ep
Figure 4-19. Raw water turbidity versus time for Plant 8.
c
>
H
Q
CD
cr
D
i!4U
220
-
200
-
180
-
160
-
140
120
100
80
60
40
\
- 1
| '
20
V
n
1
vJ I,
\A'
I '¦>
r vy
12-Feb 14-Mar 13-Apr 13-May 12-^un 12Jul 11-Aug 10-Scp
69
-------
and to allow enough repetitive training for the operator to
successfully adjust coagulant dosages in response to
variations in raw water quality. Achievement of consistent
finished water quality will thus be addressed.
SUMMARY
The CCP approach is being developed to serve as a
means, where appropriate, for improving small water
treatment facilities without construction of major modifica-
tions. This handbook presents a format for using the pro-
cedures and Chapter 4 presents findings concerning field
activities supporting the handbook development. A sum-
mary of significant findings is presented below.
CPE Findings
• The flocculation, sedimentation, and filtration proces-
ses in 18 of 22 facilities were projected to have ade-
quate capacity to handle flows equal to or in excess ol
the observed peak operating flow rates.
• Construction will be required for 15 of 22 facilities if
only postdisinfection is allowed and the current regula-
tions are adopted. Disinfection capabilities are de-
pendent on the final interpretation and implementation
of the oisinfection regulations by individual States. Use
of prechlorination would reduce the amount of con-
struction required to achieve disinfection requirements
outlined in the SWTR.
• Operations factors severely limited performance in 15
of the 21 CPEs performed. This finding, coupled with
the fact that 19 of 22 existing facilities were assessed
to have adequate capacity to meet the turbidity
removal requirements, indicates that improving opera-
tions factors could significantly improve water treat-
ment plant performance.
• Although design factors represented half of the top 10
factors identified, it was projected that these deficien-
cies could be satisfactorily addressed in many cases
by utilizing minor modifications, decreasing operating
flows, and improving process control.
• Administrative factors were identified as having a sig-
nificant impact on plant performance. Significant train-
ing of plant administrators must be an integral part of
implementation of programs to optimize water treat-
ment plant performance.
• Numerous plant-specific impacts on plant performance
were identified during the conduct of the CPEs:
• Onsite performance assessments indicated that
reported finished water turbidities were often not
representative of true performance. Continuous
recording of turbidity from each filter is considered
essential to provide operators with enough informa-
tion to minimize excursions in treated water tur-
bidities.
• Lack of attention to filter rate control devices is
resulting in deteriorated filter performance.
• Lack of attention to flow rate changes to operating
filters is resulting in deteriorated filter performance.
• Starling dirty filters is resulting in deteriorated filter
performance.
• Filter performance immediately following backwash
is often unsatisfactory. Improved chemical con-
ditioning is required to address this negative impact
on plant performance. If improved chemical con-
ditioning does not satisfactorily improve perfor-
mance immediately following a backwash,
filter-to-waste capability may be required.
• Adequate process control was only practiced in 1 of
22 facilities evaluated.
• Decreased flows and increased operating time offer
a significant alternative to construction of new
facilities for many small water treatment plants.
• CPEs had a broader perspective and were more com-
prehensive than other inspections or sanitary surveys
normally completed by State personnel. As such,
CPEs frequently identified significant performance-
limiting factors that had gone undetected during other
inspections.
• State regulatory agency involvement was essential for
successful implementation of the CCP approach in im-
proving small water plant performance.
• Exit meetings with the administrators were identified
as one of the major advantages of the CPE over other
surveys and inspections.
• State personnel began to incorporate some of the CPE
procedures into their regular inspections. However, if
the full benefits of the CPE aspect of the CCP ap-
proach are to be realized, the States will have to adopt
the overall approach. A piecsmeal effort cannot
provide the necessary comprehensive evaluation and
associated results.
CCP Findings
The findings to date have clearly demonstrated the
capability of the CCP approach to assist small com-
munities in meeting the requirements of the SWTR in an
economical fashion. Several issues remain to be
resolved:
• CCPs conducted at three plants allowed them to meet
the finished water turbidity requirements of the SWTR
without major capital improvements, primarily through
the implementation of process control programs and
operator training.
• A concise major unit process evaluation format using a
point system has recently been developed but has not
been field verified. Rather, the determination of plant
type has been accomplished based on the perfor-
70
-------
mance potential graph. Criteria used to develop the
graphs have been largely judgment based. In order for
the CPE to be readily used by less experienced
evaluators, criteria will have to be more data based
and less judgment based. Achieving this endpoint will
require numerous CCPs to be conducted at various
types of plants. Data developed by conducting CCPs
could be used to verily and refine the point rating sys-
tem to determine unit process capacity and plant type.
• The issue of who should be involved in conducting
CPEs and CCPs has not been resolved. However, the
presence of State and EPA personnel during the
development stage has enhanced acceptance of the
approach at the local level. In addition, it appears that
State involvement in conducting CPEs and providing
regulatory pressure will be necessary to achieve
broad-based use of the approach.
REFERENCES
1. U.S. EPA. 1989. Surface Water Treatment Rule.
Federal Register, Vol. 54, No. 124, 40 CFR, Parts
141 and 142, Rules and Regulations, Filtration/Disin-
fection. June.
2. Cleasby, J.L., A H. Dharmarajah, G.L. Sindt, and
E.R. Baumann. 1989. Design and Operation
Guidelines for Optimization of the High-Rate Filtration
Process: Plant Survey Results. ISBN 0-89867-478-6.
Denver, CO: American Water Works Association
and AWWA Research Foundation. September.
71
-------
Intentionally Blank Page
-------
APPENDIX A
CT Values for Inactivation of Giardia and Viruses by Free Ch
-------
Intentionally Blank Page
-------
Table A-1. CT Values lor Inactivation of Glardia Cysts by Free Chlorine at 0.5*C or Lower1
CHLORINE
pH<
=6
=6.5
P«
=7.0
pH
=7.5
CONCENTRATION
Log Inaclivalioaa
Log hietiviioM
Log hadivriioi
Log 1—rtirdii—
OS
1.0
IS
2.0
2.5
3 0
OS
10
1.5
2.0
2.5
3.0
05
1.0
1.5
2.0
2 5
3.0
0.5
1.0
IS
2 0
2.5
3.0
< *0.4
23
46
69
91
114
137
27
54
•2
109
136
163
33
65
91
130
163
195
40
79
119
158
198
237
0.6
24
47
71
94
III
141
28
56
84
112
140
161
33
67
100
133
167
200
40
80
120
159
199
239
0.1
24
48
73
97
121
145
29
57
•6
IIS
143
172
34
68
103
137
171
205
41
82
123
164
205
246
1
25
49
74
99
123
141
29
59
88
117
147
176
35
70
105
140
175
210
42
84
127
169
211
253
1.2
25
51
76
101
127
152
30
60
90
120
150
180
36
72
108
143
179
215
43
86
130
173
216
259
1.4
26
52
71
103
129
I5S
31
61
92
123
153
184
37
74
III
147
184
221
44
89
133
177
222
266
1.6
26
52
79
105
131
157
32
63
95
126
158
189
38
75
113
151
III
226
46
91
137
182
228
273
I.I
27
54
>1
100
135
162
32
64
97
129
161
193
39
77
116
154
193
231
47
93
140
116
233
279
2
28
55
>3
110
131
I6S
33
66
99
131
164
197
39
79
III
157
197
236
48
95
143
191
238
286
2.2
2>
56
U
113
141
169
34
67
101
134
168
201
40
81
121
161
202
242
50
99
149
198
248
297
2.4
29
57
>6
IIS
143
172
34
68
103
137
171
205
41
82
124
165
206
247
50
99
149
199
248
298
2 6
29
51
U
117
146
175
3S
70
105
139
174
209
42
84
126
168
210
252
SI
101
152
203
253
304
2.1
30
59
19
119
I4B
178
36
71
107
142
178
213
43
86
129
171
2M
257
52
103
155
207
258
310
3
30
60
91
121
ISI
181
36
72
109
145
III
217
44
87
131
174
218
261
S3
105
158
211
263
316
CHLORINE
P" =
SO
=8.5
pH<
=9.0
CONCENTRATION
Log had
livalia
M
Log laactivalio
M
Log laactivatkn
¦
(«¦*/*-)
0.5
1.0
IS
2.0
2 5
30
OS
1.0
15
20
2.5
30
0.5
1.0
IS
2.0
2 5
30
e
li
V
46
92
139
its
231
277
SS
no
165
219
274
329
65
130
I9S
260
325
390
06
48
95
143
191
23S
286
57
IM
171
221
215
342
68
136
204
271
339
407
0.8
49
9t
I4fl
197
246
295
59
118
177
236
295
354
70
Ml
211
211
352
422
1
SI
101
IS2
203
253
304
61
122
183
243
304
365
73
146
219
291
364
437
1.2
S2
104
157
209
261
313
63
125
188
251
313
376
75
150
226
301
376
451
1.4
54
107
161
214
261
321
65
129
194
258
323
387
77
155
232
309
317
464
1.6
55
110
165
219
274
329
66
132
199
265
331
397
80
159
239
311
391
477
l>
56
113
169
225
212
338
61
136
204
271
339
407
¦2
163
245
326
408
489
2
St
IIS
173
231
2M
346
70
139
209
278
341
417
¦3
167
250
333
417
500
2.2
S9
lit
177
235
294
3S3
71
142
213
284
355
426
IS
170
256
341
426
511
2.4
60
120
l>l
241
Wl
361
73
145
218
290
363
435
17
174
261
348
435
522
2.6
61
123
IM
245
307
368
74
148
222
296
370
444
89
178
267
355
444
533
2.8
63
125
IU
250
313
375
75
151
226
301
377
452
91
III
272
362
453
54J
3
64
127
191
255
311
382
77
153
210
307
383
460
92
184
276
368
460
552
Note: CT99.9 = CT for 3-k>g Inactivation
-------
Table A-2. CT Values for Inactivatlon of Glardla Cysts by Free Chlorine at 5 C1
>
ro
CHLORINE
pll<
=6
PH
= 6.5
PH
=7.0
Pll
=7.5
CONCENTRATION
Log laactivatioa*
Log lucUvM ioni
Log laactivatioaa
Lot InAdivfltiou
OS
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2 5
3 0
0 5
1.0
IS
2.0
2.5
3.0
0.5
1.0
15
2.0
2.5
3.0
<=0.4
16
32
49
65
81
97
20
39
59
78
98
117
23
46
70
93
116
139
28
55
83
III
138
166
0.6
17
33
SO
67
83
100
20
40
60
80
100
120
24
48
72
95
119
143
29
57
86
114
143
171
0.1
17
34
52
69
K
103
20
41
61
81
102
122
24
49
73
97
122
146
29
58
88
117
146
175
1
18
35
53
70
88
105
21
42
63
8)
104
125
25
50
75
99
124
149
30
60
90
119
149
179
1.2
18
36
54
71
89
107
21
42
64
85
106
127
25
51
76
101
127
152
31
61
92
122
153
183
1.4
18
36
55
73
91
109
22
43
65
87
108
130
26
52
78
103
129
155
31
62
94
125
156
187
16
19
37
56
74
93
III
22
44
66
88
110
132
26
53
79
105
132
158
32
64
96
128
160
192
It
19
38
57
76
95
114
23
45
68
90
113
135
27
54
II
108
135
162
33
65
98
131
163
196
2
19
39
58
77
97
116
23
46
69
92
IIS
138
28
55
83
110
138
165
33
67
100
133
167
200
2.2
20
39
59
79
98
III
23
47
70
93
117
140
28
56
85
113
141
169
34
68
102
136
170
204
2.4
20
40
60
80
100
120
24
48
72
95
119
143
29
57
16
115
143
172
35
70
105
139
174
209
26
20
41
61
81
102
122
24
49
73
97
122
146
29
58
88
117
146
175
36
71
107
142
178
213
2.8
21
41
62
83
103
124
25
49
74
99
123
148
30
59
19
119
148
178
36
72
109
145
III
217
3
21
42
63
84
105
126
25
50
76
101
126
151
30
61
91
121
152
182
37
74
III
147
114
221
CHLORINE
pM =
8.0
PH
=8.5
pH<
II
*
©
CONCENTRATION
Log laactivatioaa
Log 1—rtiyfirw
Log j—divtimn
(wg/L)
0.5
10
1.5
2 0
2.5
3.0
05
1.0
1.5
2.0
2.5
3.0
0 5
1.0
1.5
2 0
2 5
3.0
A
II
o
*
33
66
99
132
165
191
39
79
118
157
197
236
47
93
140
186
233
279
0.6
14
68
102
136
170
204
41
81
122
163
203
244
49
97
146
194
243
291
0.1
IS
70
105
140
175
210
42
84
126
168
210
252
50
100
151
201
251
301
1
36
72
108
144
ISO
216
43
87
130
173
217
260
52
104
156
208
260
312
1.2
37
74
III
147
IB4
221
45
89
134
178
223
267
S3
107
160
213
267
320
1.4
38
76
114
151
189
227
46
91
137
113
228
274
55
110
165
219
274
329
1.6
39
77
116
155
193
232
47
94
141
187
234
281
56
112
169
225
281
337
IB
40
79
119
159
198
231
48
96
144
191
239
217
58
115
173
230
281
345
2
41
II
122
162
203
243
49
98
147
196
245
294
59
118
177
235
294
353
2 2
41
13
124
165
207
248
50
100
150
200
250
300
60
120
181
241
301
361
24
42
84
127
169
211
253
51
102
153
204
255
306
61
123
184
245
307
368
2 6
43
16
129
172
215
251
52
104
156
208
260
312
63
125
188
250
313
375
2.1
44
IS
132
175
219
263
53
106
159
212
265
311
64
127
191
255
318
382
J
45
19
134
179
223
261
54
101
162
21b
270
324
65
130
195
259
324
389
Note; CTgg.g = CT for 3-log inactivation
-------
Table A-3. CT Values for Inactivation of Giardia Cysts by Free Chlorine at 10'C1
CHLORINE
pH<
=6
pH
= 65
pll =
=7.0
pll
it
CONCENTRATION
Log loadivalioaa
Log ImdmiioM
Log ludivriKxts
Log laadmlkai
(•¦k/L)
o.s
1.0
1.5
2.0
2.5
3.0
0.5
1.0
15
2.0
2.5
3.0
05
1.0
IS
2.0
2.5
30
0.5
1.0
1.5
2.0
2.5
3.0
<=0 4
12
24
37
49
61
73
15
29
44
59
73
88
17
35
52
69
87
104
21
42
63
S3
104
125
0.6
13
25
38
50
63
75
15
30
45
60
75
90
IS
36
54
71
89
107
21
43
64
85
107
128
o.a
13
26
39
52
65
78
15
31
46
61
77
92
IS
37
55
73
92
110
22
44
66
87
109
131
1
13
26
40
53
66
79
16
31
47
63
78
94
19
37
56
75
93
112
22
45
67
89
112
134
1.2
13
27
40
53
67
80
16
32
48
63
79
95
19
38
57
76
95
114
23
46
69
91
114
137
1.4
14
27
41
55
61
82
16
33
49
65
82
98
19
39
58
77
97
116
23
47
70
93
117
HO
1.6
14
28
42
55
69
83
17
33
50
66
83
99
20
40
60
79
99
119
24
48
72
96
120
144
I.I
14
29
43
57
72
86
17
34
51
67
84
101
20
41
61
SI
102
122
25
49
74
98
123
147
2
IS
29
44
58
73
87
17
35
52
69
87
104
21
41
62
83
103
124
25
so
75
100
125
150
2.2
IS
30
45
59
74
89
IS
35
53
70
88
105
21
42
64
85
106
127
26
51
77
102
128
153
2.4
IS
30
45
60
75
90
IS
36
54
71
89
107
22
43
65
86
108
129
26
52
79
105
131
157
2.6
IS
31
46
61
77
92
IS
37
55
73
92
110
22
44
66
87
109
131
27
53
80
107
133
160
2.8
16
31
47
62
78
93
19
37
56
74
93
III
22
45
67
89
112
134
27
54
82
109
136
>63
3
16
32
48
63
79
95
19
38
57
75
94
113
23
46
69
91
114
137
28
55
S3
III
138
166
CHLORINE
PH =
8.0
pH
=8.5
pll<
=9.0
CONCENTRATION
Log laadivatioM
Log InactivatioM
Log laactivMioM
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
IS
2.0
2.5
30
A
II
o
*
25
50
75
99
124
149
30
59
89
118
148
177
35
70
105
139
174
209
0.6
26
51
77
102
128
153
31
61
92
122
153
183
36
73
109
145
182
211
0.8
26
53
79
105
132
158
32
63
95
126
158
189
38
75
113
151
111
226
1
27
54
81
108
135
162
33
65
98
130
163
195
39
78
117
156
195
234
1.2
28
55
83
III
138
166
33
67
100
133
167
200
40
80
120
160
200
240
1.4
21
57
85
113
142
170
34
69
103
137
172
206
41
82
124
165
206
247
1.6
29
58
87
116
145
174
35
70
106
141
176
211
42
M
127
169
211
253
1.8
30
60
90
119
149
179
36
72
108
143
179
215
43
86
130
173
216
259
2
30
61
91
121
152
182
37
74
III
147
184
221
44
88
133
177
221
2&S
2.2
31
62
93
124
155
186
38
75
113
ISO
188
225
45
90
136
181
226
271
2.4
32
63
95
127
158
190
38
77
115
153
192
230
46
92
138
184
230
276
2.6
32
65
97
129
162
194
39
78
117
156
195
234
47
94
141
187
234
281
2.8
33
66
99
131
164
197
40
80
120
159
199
239
48
96
144
191
239
217
3
34
67
101
134
168
201
41
SI
122
162
203
243
49
97
146
I9S
243
292
Note: CTgg s = CT for 3-log inaclivatlon
-------
Table A-4. CT Values for Inactivation of Glardia Cysts by Free Chlorine at 15'C1
CHLORINE
pH<
=6
PH
=6.5
PH =
7.0
r*'
II
CONCENTRATION
Log Inactivalioaa
Log iMdivatiooj
Log InactivatioiM
Log Inactive
iou
O.S
1.0
15
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
O.S
10
1.5
2.0
2 5
3.0
0.5
1.0
1.5 2.0
2.5
3.0
<=0.4
1
16
25
33
41
49
10
20
30
39
49
59
12
23
35
47
58
70
14
28
42
55
69
13
0.6
•
17
25
33
42
50
10
20
30
40
SO
60
12
24
36
48
60
72
14
29
43
57
72
86
0.1
9
17
26
35
43
52
10
20
31
41
51
61
12
24
37
49
61
73
15
29
44
59
71
II
1
9
IB
27
35
44
53
II
21
32
42
53
63
13
25
38
50
63
75
15
30
45
60
75
90
1.2
9
II
27
36
45
54
II
21
32
43
53
64
13
25
38
SI
63
76
IS
31
46
61
77
92
1.4
9
II
21
37
46
SS
II
22
33
43
S4
65
13
26
39
S2
65
78
16
31
47
63
71
*4
1.6
9
19
21
37
47
56
II
22
33
44
55
66
13
26
40
53
66
79
16
32
48
64
80
96
1.1
10
19
29
31
41
57
II
23
34
45
57
68
14
27
41
54
68
81
16
33
49
6S
12
98
2
10
19
29
39
41
58
12
23
35
46
58
69
14
28
42
SS
69
83
17
33
SO
67
S3
100
2.2
10
20
30
39
49
59
12
23
35
47
58
70
14
28
43
57
71
85
17
34
SI
68
IS
102
2.4
10
20
30
40
SO
60
12
24
36
48
60
72
14
29
43
57
72
86
18
3S
S3
70
81
105
2.6
10
20
31
41
51
61
12
24
37
49
61
73
IS
29
44
59
73
88
18
36
S4
71
89
107
2.S
10
21
31
41
52
62
12
25
37
49
62
74
IS
30
45
59
74
19
II
36
55
73
91
109
3
II
21
32
42
S3
63
13
25
38
51
63
76
15
30
46
61
76
91
19
37
S6
74
93
III
CHLORINE
PH =
1.0
PH
=8.5
pll<
=9.0
CONCENTRATION
Log laactivatioaa
Log Inactivalioa*
Log lurtivtio—
OS
1.0
15
2.0
2.5
3.0
O.S
1.0
1.5
2.0
2.5
3.0
0.5
10
1.5
2.0
25
3.0
<=0.4
17
33
SO
66
13
99
20
39
59
79
98
III
23
47
70
93
117
140
0.6
17
34
SI
61
85
102
20
41
61
81
102
122
24
49
73
97
122
146
0.1
II
3S
53
70
M
I0S
21
42
63
84
I0S
126
25
50
76
101
126
151
1
II
36
54
72
90
108
22
43
65
87
ioa
130
26
52
71
104
130
IS6
1.2
19
37
S6
74
93
III
22
45
67
89
112
134
27
53
80
107
133
160
1.4
19
31
57
76
95
114
23
46
69
91
114
137
28
55
83
110
138
I6S
1.6
19
39
58
77
97
116
24
47
71
94
118
141
28
56
IS
113
141
169
LI
20
40
60
79
99
119
24
48
72
96
120
144
29
58
17
115
144
173
2
20
41
61
II
102
122
25
49
74
98
123
147
30
59
89
118
148
177
2 2
21
41
62
S3
103
124
25
50
75
100
125
150
30
60
91
121
151
181
2.4
21
42
64
85
106
127
26
51
77
102
128
153
31
61
92
123
153
184
2 6
22
43
65
86
108
129
26
52
78
104
130
156
31
63
94
125
157
188
2.S
22
44
66
88
ItO
132
27
53
80
106
133
159
12
64
96
127
159
191
3
22
45
67
89
112
134
27
54
81
108
1)5
162
33
65
98
130
163
195
Note: CT99.9= CT for 3-log Inactivation
-------
Table A-5. CT Values for Inactivation of Giardia Cysts by Free Chlorine al 20"C1
CHLORINE
pH<
=6
1*
=6.5
pH =
=7.0
pH
=7.5
CONCENTRATION
Log iMdraitioei
Log ludivriioM
Log lnactivatioM
Log laactmtioaa
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
IS
2.0
2.5
3 0
0 5
1.0
IS
2.0
2.5
3.0
05
10
IS
2.0
2.S
3.0
<=0.4
6
12
18
24
30
36
7
15
22
29
37
44
9
17
26
35
43
S2
10
21
31
41
52
62
0.6
6
13
19
25
32
38
t
IS
23
30
38
45
9
IB
27
36
45
54
II
21
32
43
S3
64
0.B
7
13
20
26
33
39
8
IS
23
31
38
46
9
18
28
37
46
55
II
22
33
44
SS
<6
1
7
13
20
26
33
39
8
16
24
31
39
47
9
19
28
37
47
56
II
22
34
45
56
67
12
7
13
20
27
33
40
t
16
24
32
40
48
10
19
29
38
48
57
12
23
3S
46
58
69
1.4
7
14
21
27
34
41
t
16
25
33
41
49
10
19
29
39
48
58
12
23
35
47
SS
70
1.6
7
14
21
21
35
42
a
17
25
33
42
so
10
20
30
39
49
59
12
24
36
4S
60
72
1.8
7
14
22
29
36
43
9
17
26
34
43
SI
10
20
31
41
SI
61
12
25
37
49
62
74
2
7
IS
22
29
37
44
9
17
26
35
43
S2
10
21
31
41
52
62
13
25
38
SO
63
75
2.2
7
IS
22
29
37
44
9
18
27
35
44
S3
11
21
32
42
S3
63
13
26
39
51
64
77
2.4
a
IS
23
30
31
45
9
18
27
36
45
54
11
22
33
43
54
65
13
26
39
52
65
78
2.6
i
IS
23
31
31
46
9
IS
28
37
46
SS
11
22
33
44
55
66
13
27
40
53
67
80
2 8
a
16
24
31
39
47
9
19
28
37
47
S6
11
22
34
45
56
67
14
27
41
54
68
SI
3
a
16
24
31
39
47
10
19
29
38
48
57
II
23
34
45
57
68
14
2S
42
SS
69
S3
CHLORINE
pH =
8.0
pH
= 8.5
pH <
=9.0
CONCENTRATION
Log InoctivaUo
m
Log laacthralioM
Log Inactivrtioa*
0 5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
15
20
2.5
3.0
A
II
O
*
12
25
37
49
62
74
IS
30
45
59
74
89
IS
35
S3
70
88
105
0.6
13
26
39
SI
64
77
IS
31
46
61
77
92
IS
36
55
73
91
109
0.B
13
26
40
53
66
79
16
32
48
63
79
95
19
38
57
75
94
113
1
14
27
41
54
68
81
16
33
49
65
82
98
20
39
59
78
98
117
1.2
14
28
42
55
69
83
17
33
50
67
83
100
20
40
60
80
100
120
1.4
14
28
43
57
71
85
17
34
52
69
86
103
21
41
62
82
103
123
1.6
IS
29
44
58
73
87
18
35
53
70
88
105
21
42
63
84
105
126
II
IS
30
45
59
74
89
18
36
54
72
90
108
22
43
65
86
108
129
2
IS
30
46
61
76
91
18
37
55
73
92
110
22
44
66
88
110
132
2.2
16
31
47
62
71
93
19
31
S7
75
94
113
23
45
68
90
113
135
2.4
16
32
4B
63
79
95
19
38
51
77
96
115
23
46
69
92
IIS
138
2.6
16
32
49
65
81
97
20
39
59
78
91
117
24
47
71
94
IIS
141
2 8
17
33
50
66
83
99
20
40
60
79
99
119
24
48
72
95
119
143
3
17
34
51
67
84
101
20
41
61
SI
102
122
24
49
73
97
122
146
Note: CTgg.g = CT for 3-log inaclivation
-------
Table A-6. CT Values for Inactivatlon of Giardia Cysts by Free Chlorine at 25'C1
CHLORINE
pH<
=6
pH
=6.5
PH =
7.0
pH
= 7.5
CONCENTRATION
Log Inadlvatioaa
Log Inaclivatiutu
Log lirtivitkmj
Log iHdnrdini
(m g/L)
05
1.0
1.5
2.0
2.5
3.0
0 5
1.0
1.5
2.0
2.5
3 0
0.5
10
I.S
20
2.5
30
0.5
1.0
I.S
2.0
2.5
3.0
<=0.4
4
1
12
16
20
24
5
10
IS
19
24
29
6
12
18
23
29
35
7
14
21
28
35
42
0.6
4
1
13
17
21
25
5
10
IS
20
25
30
6
12
18
24
30
36
7
14
22
29
36
43
0.1
' 4
9
13
17
22
26
5
10
16
21"
26
31
6
12
19
25
31
37
7
15
22
29
37
44
1
4
9
13
17
22
26
5
10
16
21
26
31
6
12
19
25
31
37
8
IS
23
30
38
45
1.2
5
9
14
II
23
27
5
II
16
21
27
32
6
13
19
25
32
38
8
IS
23
31
38
46
14
5
9
14
18
23
27
6
II
17
22
28
33
7
13
20
26
33
39
8
16
24
31
39
47
1.6
5
9
14
19
23
28
6
II
17
22
28
33
7
13
20
27
33
40
8
16
24
32
40
48
1.1
S
10
15
19
24
29
6
II
17
23
28
34
7
14
21
27
34
41
8
16
25
33
41
49
2
S
10
15
19
24
29
6
12
IS
23
29
3S
7
14
21
27
34
41
8
17
2S
33
42
50
2.2
5
10
IS
20
25
30
6
12
II
23
29
35
7
14
21
28
35
42
9
17
26
34
43
SI
2.4
5
10
IS
20
25
30
6
12
II
24
30
36
7
14
22
29
36
43
9
17
26
35
43
52
2.6
5
10
16
21
26
31
6
12
19
25
31
37
7
IS
22
29
37
44
9
IS
27
35
44
53
2.1
5
10
16
21
26
31
6
12
19
25
31
37
8
IS
23
30
38
45
9
IB
27
36
45
54
3
5
II
16
21
27
32
6
13
19
25
32
38
8
IS
23
31
38
46
9
II
28
37
46
55
CHLORINE
pll«
S.O
=85
pll<
=9.0
CONCENTRATION
Log 1—rtivlioaa
Log Inactrvatioai
Log Inactivalinsa
(rag/L)
0.5
1.0
15
2.0
2 5
30
0.5
1.0
I.S
2.0
2.5
3.0
05
10
15
20
2.5
3.0
<=0.4
•
17
25
33
42
50
10
29
30
39
49
59
12
23
35
47
58
70
0.6
9
17
26
34
43
51
10
20
31
41
SI
61
12
24
37
49
61
73
0.1
9
II
27
35
44
53
II
21
32
42
53
63
13
25
31
50
63
75
1
9
IB
27
36
45
54
II
22
33
43
54
65
13
26
39
52
65
78
1.2
9
II
28
37
46
55
II
22
34
45
56
67
13
27
40
53
67
80
1.4
10
19
29
38
48
57
12
23
35
46
58
69
14
27
41
55
68
82
1.6
10
19
29
39
48
58
12
23
35
47
58
70
14
28
42
56
70
84
1.1
10
20
30
40
so
60
12
24
36
48
60
72
14
29
43
57
72
86
2
10
20
31
41
51
61
12
25
37
49
62
74
IS
29
44
59
73
88
2.2
10
21
31
41
52
62
13
25
38
50
63
75
IS
30
45
60
75
90
2.4
II
21
32
42
53
63
13
26
39
51
64
77
15
31
46
61
77
92
2.6
II
22
33
43
54
65
13
26
39
52
65
78
16
31
47
63
78
94
2.8
11
22
33
44
55
66
13
27
40
53
67
80
16
32
48
64
SO
96
3
II
22
34
45
56
67
14
27
41
54
68
SI
16
32
49
65
SI
97
Note: CT99.9 = CT for 3-log inactivatlon
-------
Table A-7. CT Values for Inactivation of Viruses by Free Chlorine1
Log Inactivation
2.0 pH 3.0 pH 4.0 pH
Temperature (C) 6-9 10 6-9 10 6-9 10
0.5 6 45 9 66 12 90
5 4 30 6 44 8 60
10 3 22 4 33 6 45
15 2 15 3 22 4 30
20 1 11 2 16 3 22
25 1 7 1 11 2 15
Table A-8. CT Values for Inactivation of Glardia Cysts by Chlorine Dioxide1
Temperature (C)
Inactivation <=1 5 10 15 20 25
0.5-log 10 4.3 4 3.2 2.5 2
1 -log 21 8.7 7.7 6.3 5 3.7
1.5-log 32 13 12 10 7.5 5.5
2-log 42 17 15 13 10 7.3
2.5-k>g 52 22 19 16 13 9
3-log 63 26 23 19 15 11
Table A-9. CT Values for Inactivation of Viruses by Chlorine Dioxide pH 6-91
Temperature (G)
Removal <=1 5 10 15 20 25
2-Iog 8.4 5.6 4.2 2.8 2.1 1.4
3-log 25.6 17.1 12.8 8.6 6.4 4.3
4-log 50.1 33.4 25.1 16.7 12.5 8.4
A-7
-------
Table A-10. CT Values for Inactivation of Giardia Cysts by Ozone1
Temperature (C)
Inactivation
<=1
5
10
15
20
25
0,5-log
0.48
0.32
0.23
0.16
0.1
0.08
1 -log
0.97
0.63
0.48
0.32
0.2
0.16
1.5-log
1.5
0.95
0.72
0.48
0.36
0 24
2-log
1.9
1.3
0.95
0.63
0.48
0.32
2.5-log
2.4
1.6
1.2
0.79
0.60
0.40
3-log
2.9
1.9
1.43
0.95
0.72
0.48
Table A-11. CT Values for Inactivation of Viruses by Ozone1
Temperature (C)
Inactivation
<=1
5
10
15
20
25
2-log
0.9
0.6
0.5
0.3
0.25
0.15
3-log
1.4
0.9
0.8
0.5
0.4
0.25
4-log
1.8
1.2
1.0
0.6
0.5
0.3
Table A-12. CT Values for Inactivation of Giardia Cysts by Chioramine Ph 6-91
Temperature (C)
Inactivation
<=1
5
10
15
20
25
0.5-log
635
365
310
250
185
125
1 -log
1,270
735
615
500
370
250
1.5-log
1,900
1.100
930
750
550
375
2-log
2,535
1,470
1,230
1,000
735
500
2.5-log
3,170
1,830
1,540
1,250
915
625
3-log
3,800
2,200
1,850
1,500
1,100
750
A-8
-------
Table A-13. CT Values for Inactivation of Viruses by Chloramlne1
Temperature (C)
Inactivation
<=1
5
10
15
20
25
2-log
1,243
857
643
428
321
214
3-log
2,063
1,423
1,067
712
534
356
4-log
2,883
1,988
1,491
994
746
497
Table A-14. CT Values for Inactivatlon of Viruses by UV1
Log Inactivation
2.0
3.0
21 36
1 All tables in this appendix are taken from Guidance Manual for Compliance with the Filtration and Disinfection Re-
quirements for Public Water Systems Using Surface Water Sources, Appendix E, Science and Technology Branch,
Criteria and Standards Division, Office of Drinking Water, U.S. EPA, Washington, DC, October 1989.
A-9
-------
Intentionally Blank Page
-------
3-/
APPENDIX B
Classification System, Factor Checklist, and Definitions for Assessing Performance-
Limiting Factors
-------
Intentionally Blank Page
-------
CPE SUMMARY SHEET TERMS
PLANT TYPE
RAW WATER SOURCE
PLANT PERFORMANCE SUMMARY
RANKING TABLE
RANKING
CLASS A OR B
PERFORMANCE LIMITING
FACTORS/CATEGORY
Brief but specific description of type of plant (e.g., conventional
with flash mix, flocculation, sedimentation, filtration and chlorine
disinfection or direct filtration with flash mix, flocculation
and disinfection).
Brief description of water source (e.g., surface water including
name of river or ground water including formation).
Brief description of plant performance as related to desired
finished water quality.
A list of the major causes of decreased plant performance
and reliability.
Causes of decreased plant performance and reliability, with the
most critical ones listed first (typically only "A" and "BM factors
are listed).
Identify factors as A (major effect on a long-term repetitive basis)
or B (minimum effect on a routine basis or major effect on a
periodic basis).
Items identified from the Checklist of Performance Limiting
Factors.
Identify factor category (e.g., administration, design, operations,
or maintenance).
B-1
-------
CPE SUMMARY SHEET FOR RANKING PERFORMANCE LIMITING FACTORS
Plant Name/Location
CPE Performed by DATE
Plant Type:
Raw Water Source:
Plant Performance Summary:
RANKING TABLE
RANKING CLASS A or B PERFORMANCE LIMITING FACTOR/CATEGORY
1 _ _ _
2
3 _
4
5
6
7
8
9
10 _
11
1 2
13
14
15
A—Major effect on a long-term repetitive basis.
B—Minimum effect on a routine basis or major effect on a periodic basis.
C—Minor effect.
B-2
-------
CPE CLASSIFICATION SYSTEM, FACTORS CHECKLIST, AND DEFINITIONS
FOR ASSESSING PERFORMANCE LIMITING FACTORS
CLASSIFICATION SYSTEM FOR PRIORITIZING PERFORMANCE LIMITING FACTORS*
RATING ADVERSE EFFECT OF FACTOR ON PLANT PERFORMANCE
A Major effect on a long-term repetitive basis.
B Minimum effect on a routine basis or major effect on a periodic basis.
C Minor effect.
NR No Rating - factor has no adverse effect on plant performance (i.e., satisfactory
assessment of this potentially performance limiting item).
"Factors are assessed based on their adverse effect on achieving desired finished water quality.
B-3
-------
CHECKLIST OF PERFORMANCE LIMITING FACTORS
FACTOR RATING* COMMENTS
A. Administration
1. Plant Administrators
a. Policies
b. Familiarity with Plant Needs
c. Supervision
d. Planning
2. Plant Staff
a. Manpower
1) Number
2) Plant Coverage
3) Workload Distribution
4)Personnel Turnover
b. Morale
1) Motivation
2) Pay
3) Work Environment
c. Staff Qualifications
1) Aptitude
2) Level of Education
3) Certification
d. Productivity
3. Financial
a. Insufficient Funding
b. Unnecessary Expenditures
c. Bond Indebtedness
4. Water Demand
B. Maintenance
1. Preventive
a. Lack of Program
b. Spare Parts Inventory
2. Corrective
a. Procedures
b. Critical Parts Procurement
3. General
a. Housekeeping
b. References Available
c. Staff Expertise
d. Technical Guidance
(Maintenance)
e. Equipment Age
*A— Major effect on a long-term repetitive basis.
B—Minimum effect on a routine basis or major effect on a periodic basis.
C—Minor effect.
NR—No Rating.
B-4
-------
CHECKLIST OF PERFORMANCE LIMITING FACTORS (cont.)
FACTOR RATING* COMMENTS
C. Design
1. Raw Water
a. THM Precursors
b. Turbidity
c. Seasonal Variation
d. Watershed/Reservoir
Management
2. Unit Design Adequacy
a. Pretreatment
1) Intake Structure
2) Presedimentation Basin
3) Prechlorination
b. Low Service Pumping
c. Flash Mix
d. Fiocculation
e. Sedimentation
f. Filtration
g. Disinfection
h. Sludge Treatment
i. Ultimate Sludge/Back-
wash Water Disposal
j. Fluoridation
3. Miscellaneous
a. Process Flexibility
b. Process Controllability
c. Process Automation
d. Lack of Standby Units
for Key Equipment
e. Flow Proportioning to Units
f. Alarm Systems
g. Alternate Power Source
h. Laboratory Space
and Equipment
i. Sample Taps
j. Plant Inoperability
Due to Weather
k. Return Process Streams
*A— Major effect on a long-term repetitive basis.
B— Minimum effect on a routine basis or major effect on a periodic basis.
C—Minor effect.
NR—No Rating.
B-5
-------
CHECKLIST OF PERFORMANCE LIMITING FACTORS (cont.)
FACTOR RATING* COMMENTS
D. Operation
1. Testing
a. Performance Monitoring
b. Process Control Testing
2. Process Control Adjustments
a. Water Treatment
Understanding
b. Application of
Concepts and Testing
to Process Control
c. Technical Guidance
(Operations)
d. Training
e. Insufficient Time on the Job
3. O&M Manual/Procedure
a. Adequacy
b. Use
4. Distribution System
E. Miscellaneous
1 .
2 .
3 .
4 .
5 .
6 .
*A— Major effect on a long-term repetitive basis.
B—Minimum effect on a routine basis or major effect on a periodic basis.
C— Minor effect.
NR—No Rating.
B-6
-------
DEFINITIONS FOR ASSESSING PERFORMANCE LIMITING FACTORS
CATEGORY
EXPLANATION
A. ADMINISTRATION
1. Plant Administrators
a. Policies
b. Familiarity with Plant Needs
c. Supervision
d. Planning
2. Plant Staff
a. Manpower
1) Number
2) Plant Coverage
3) Workload Distribution
4) Personnel Turnover
Do operating staff members have authority to make
required operation (e.g., adjust chemical feed),
maintenance (e.g., hire electrician), and/or administrative
(e.g., purchase critical piece of equipment) decisions, or do
policies cause critical decisions to be delayed, which in turn
affects plant performance and reliability? Does any
established administrative policy limit plant performance
(e.g., non-support of training; or plant funding too low
because of emphasis to avoid rate increases)?
Do administrators have a first-hand knowledge of plant
needs through plant visits or discussions with operators? If
not, has this been a cause of poor plant performance and
reliability through poor budget decisions, poor staff morale,
or limited support for plant modifications?
Do management styles, organizational capabilities,
budgeting skills, or communication practices at any
management level adversely impact the plant to the extent
that performance is affected?
Does lack of long-range plans for facility replacement,
alternative source waters, emergency response, etc.
adversely impact plant performance?
Does a limit to the number of people employed have a
detrimental effect on plant operations or maintenance (e.g.,
not getting the necessary work done)?
Is plant coverage adequate to accomplish necessary
operational activities? Can appropriate adjustments be
made during the evenings, weekends, or holidays? For
example, is staff available to respond to changing raw water
quality characteristics during periods of operation?
Does the improper distribution of adequate manpower
(e.g., a higher priority on maintenance tasks) prevent
process adjustments from being made or cause them to
be made at inappropriate times, resulting in poor plant
performance?
Does a high personnel turnover rate cause operation and/or
maintenance problems that affect process performance or
reliability?
B-7
-------
DEFINITIONS FOR ASSESSING PERFORMANCE LIMITING FACTORS (cont.)
CATEGORY EXPLANATION
b. Morale
1) Motivation
2) Pay
3) Work Environment
c. Staff Qualifications
1) Aptitude
2) Level of Education
3) Certification
d. Productivity
3. Financial
a. Insufficient Funding
b. Unnecessary Expenditures
c. Bond Indebtedness
4. Water Demand
Does the plant staff want to do a good job because they are
motivated by self-satisfaction?
Does a low pay scale or benefit package discourage more
highly qualified persons from applying for operator positions
or cause operators to leave after they are trained?
Does a poor work environment create a condition for more
"sloppy work habits" and lower operator morale?
Does the lack of capacity for learning or understanding new
ideas of critical staff members cause improper O&M
decisions leading to poor plant performance or reliability?
Does a low level of education result in poor O&M
decisions? Does a high level of education cause needed
training to be felt unnecessary?
Does the lack of adequately certified personnel result in
poor O&M decisions?
Does the plant staff conduct the daily operation and
maintenance tasks in an efficient manner? Is time used
efficiently?
Does the lack of available funds (e.g., inadequate rate
structure) cause poor salary schedules, insufficient stock of
spare parts that results in delays in equipment repair,
insufficient capital outlays for improvements or
replacement, lack of required chemicals or chemical feed
equipment, etc.?
Does the manner in which available funds are utilized
cause problems in obtaining needed equipment, staff, etc?
Are funds spent on lower priority items while needed, higher
priority items are unfunded?
Does the annual bond debt payment limit the amount of
funds available for other needed items such as equipment,
staff, etc.?
Does excessive water use caused by declining rate
structure; concessions to industry; or high unaccounted for
use exceed the capability of plant unit processes and,
therefore, degrade plant performance?
B-8
-------
DEFINITIONS FOR ASSESSING PERFORMANCE LIMITING FACTORS (cont.)
CATEGORY EXPLANATION
B. MAINTENANCE
1. Preventive
a. Lack of Program Does the absence or lack of an effective scheduling and
recording procedure cause unnecessary equipment failures
or excessive downtime that results in plant performance or
reliability problems?
b.Spare Parts Inventory Does a critically low or nonexistent spare parts inventory
cause unnecessary long delays in equipment repairs that
result in degraded process performance?
2. Corrective
a. Procedures Are procedures available to initiate maintenance activities
on observed equipment operating irregularities (e.g., work
order system)? Does the lack of emergency response
procedures result in activities that fail to protect process
needs during breakdowns of critical equipment (e.g.,
maintaining disinfectant or coagulant feeds during
equipment breakdowns)?
b. Critical Parts Procurement Do delays in getting replacement parts caused by
procurement procedure result in extended periods of
equipment downtime?
3. General
a. Housekeeping Does a lack of good housekeeping procedures (e.g.,
unkempt, untidy, or cluttered working environment) cause
an excessive equipment failure rate?
b. References Available Does the absence or lack of good equipment reference
sources (maintenance portion of O&M Manual, equipment
catalogs, etc.) result in unnecessary equipment failure
and/or downtime for repairs ?
c. Staff Expertise Does the plant staff have the necessary expertise to keep
the equipment operating and to make equipment repairs
when necessary?
d. Technical Guidance (Maintenance) Does inappropriate guidance for repairing, maintaining, or
installing equipment from a technical resource (e.g.,
equipment supplier or contract service) result in equipment
downtime that adversely affects performance? If technical
guidance is necessary to decrease equipment downtime, is
it available and retained?
e. Equipment Age Does the age or outdatedness of critical pieces of
equipment cause excessive equipment downtime and/or
inefficient process performance and reliability (due to
unavailability of replacement parts)?
B-9
-------
DEFINITIONS FOR ASSESSING PERFORMANCE LIMITING FACTORS (cont.)
CATEGORY EXPLANATION
C. DESIGN
1. Raw Water
a. THM Precursors
b. Turbidity
c. Seasonal Variation
d. Watershed/Reservoir Management
2. Unit Design Adequacy
a. Pretreatment
1) Intake Structure
2) Presedimentation Basin
3) Prechlorination
b. Low Service Pumping
c. Flash Mix
d. Flocculation
Does the presence of raw water quality characteristics over
and above what the plant was designed for, or over and
above what is thought to be tolerable, cause degraded
process performance by one or more of the items (a-d)
listed below?
Do seasonal variations such as change in temperature or
high turbidity during spring runoff exist?
Do facilities exist to control raw water quality entering the
plant (e.g., can intake levels be varied, can chemicals be
added to control aquatic growth, do watershed
management practices adequately protect raw water
quality)?
Do the design features of any pretreatment unit cause
problems in downstream equipment or processes that have
led to degraded plant performance?
Does the design of the intake structure result in excessive
clogging of screens, a buildup of silt, or passage of solids
that damages downstream processes?
Does a deficient design cause poor sedimentation that
results in poor plant performance (e.g., inlet configuration,
size, type, or depth of the basin; or placement or length of
the weirs)?
Does prechlorination cause excessive finished water
disinfection byproducts?
Does the existence of high volume constant speed pumps
cause undesirable hydraulic loadings on downstream unit
processes?
Does a lack of or inadequate mixing result in excessive
chemical use or insufficient coagulation to the extent that it
impacts plant performance?
Does the performance of the flocculation unit process
contribute to problems in downstream unit processes that
have degraded plant performance? Does a lack of
flocculation time or flocculation stages with variable energy
input result in poor floe formation and degrade plant
performance?
B-10
-------
DEFINITIONS FOR ASSESSING PERFORMANCE LIMITING FACTORS (cont.)
CATEGORY EXPLANATION
e. Sedimentation
f. Filtration
g. Disinfection
h. Sludge Treatment
i. Ultimate Sludge/ Backwash
Water Disposal
j. Fluoridation
3. Miscellaneous
a. Process Flexibility
b. Process Controllability
Does a deficient design cause poor sedimentation that
results in poor filter performance (e.g., inlet configuration,
size, type, or depth of the basin; or placement or length of
the weirs)?
Does the size of filter, or the type, depth, and effective size
of filter media hinder its ability to adequately treat water?
Are the surface wash and backwash facilities adequate to
maintain a clean filter bed? Have the underdrains or
support gravels been damaged or disturbed to the extent
that filter performance is compromised?
Do the facilities have any design limitations that contribute
to poor disinfection (e.g., proper mixing, detention time,
feed rates, proportional feed, etc.)?
Does the type or capacity of sludge treatment processes
cause process operation problems that degrade plant
performance?
Are the sludge and backwash water facilities and disposal
area of sufficient size and type to ensure that poor plant
performance does not occur or applicable permits
regulating the discharge are not violated?
Do the fluoridation facilities have any design limitations that
result in an inability to achieve regulated fluoride levels
(e.g., feed rates, proportional feed, etc.)?
The design "miscellaneous" category covers areas of
design inadequacy not specified in the previous design
categories. (Space is available in the Checklist to
accommodate additional items not listed.)
Do chemical feed facilities have various feed points to
optimize treatment (e.g., feed alum and cationic polymers
at flash mix, feed non-ionic or anionic polymers at points
where mixing is gentle)? Do facilities exist to feed the types
of chemicals required to produce a high quality stable
finished water (e.g., coagulant aids, flocculant aids, filter
aids, stabilization chemicals)?
Do the existing process control features provide adequate
adjustment and measurement of plant flow rate, backwash
flow rate, filtration rate, and flocculation mixing inputs? Do
chemical feed facilities provide adjustable feed ranges that
are easily set for operation at all required dosages? Do
chemical feed controls remain set once adjusted or do they
vary? Are chemical feed rates easily measured?
B-11
-------
DEFINITIONS FOR ASSESSING PERFORMANCE LIMITING FACTORS (cont.)
CATEGORY EXPLANATION
c. Process Automation
d. Lack of Standby Units
for Key Equipment
e. Flow Proportioning Units
f. Alarm Systems
g. Alternate Power Source
h. Laboratory Space and Equipment
i. Sample Taps
j. Plant Inoperability Due to Weather
k. Return Process Streams
Does the lack of needed automatic monitoring or control
devices (streaming current detector, continuous recording
turbidimeter, etc.) cause excessive operator time for
process control and monitoring? Does the automatic
operation of critical unit processes degrade plant
performance during startup and shutdown?
Does the lack of standby units for key equipment cause
degraded process performance during breakdown or
during necessary preventive maintenance activities (e.g.,
backwash pumps and chemical feeders, etc.)?
Does inadequate flow proportioning or flow splitting to
duplicate units cause problems or partial unit overloads that
degrade effluent quality or hinder achievement of optimum
process performance?
Does the absence or inadequacy of an alarm system for
critical pieces of equipment or processes cause degraded
process performance (e.g., raw or finished water turbidity)?
Does the absence of an alternate power source cause
problems in reliability of plant operation leading to degraded
plant performance?
Does the absence of an adequately equipped laboratory
limit plant performance?
Does a lack of sample taps on key process flow streams
(e.g., individual filters, sedimentation basin solids,
backwash recycle streams) for sampling prevent needed
information from being obtained?
Are certain units in the plant extremely vulnerable to
weather changes and, as such, do not operate at all or do
not operate as efficiently as necessary to achieve the
required performance? Do poor roads leading into the plant
cause it to be inaccessible during certain periods of the
year for chemical or equipment delivery or for routine
operation?
Does excessive volume and/or a highly turbid return
process flow stream (e.g., backwash return flow) cause
adverse effects on process performance, equipment
problems, etc.? Does the inability to measure or sample
these streams degrade plant performance?
B-12
-------
DEFINITIONS FOR ASSESSING PERFORMANCE LIMITING FACTORS (cont.)
CATEGORY
EXPLANATION
D. OPERATION
1. Testing
a. Performance Monitoring
b. Process Control Testing
2. Process Control Adjustments
a. Water Treatment Understanding
b. Application of Concepts and
Testing to Process Control
c. Technical Guidance (Operations)
d. Training
e. insufficient Time On Job
3. O&M Manual/Procedures
a. Adequacy
b. Use
Are plant and distribution system monitoring tests truly
representative of performance?
Does the absence or wrong type of process control testing
cause improper operational control decisions to be made
(e.g., does filter performance evaluation support finished
water turbidity data)?
Is the operator's lack of basic understanding of water
treatment (e.g., limited exposure to terminology, lack of
understanding of the function of unit processes, etc.) a
factor in poor operational decisions and poor plant
performance or reliability?
Is the staff deficient in the application of their knowledge
of water treatment and interpretation of process control
testing such that improper process control adjustments are
made?
Does inappropriate operational information received from a
technical resource (e.g., design engineer, equipment
representative, state trainer or inspector) cause improper
operational decisions to be implemented or continued?
Does inattendance at available training programs result in
poor process control decisions by the plant staff or
administrators?
Does the short time on the job and associated unfamiliarity
with plant needs result in the absence of process control
adjustments or in improper process control adjustments
being made (e.g., opening or closing a wrong valve, turning
on or off a wrong chemical feed pump, backwashing a filter
incorrectly, etc.)?
Does inappropriate guidance provided by the O&M
Manual/Procedures result in poor or improper operation
decisions?
Does the operator's failure to utilize a good O&M
Manual/Procedures cause poor process control and poor
treatment that could have been avoided?
4. Distribution System
Are distribution system operating procedures (e.g., flushing,
reservoir management, etc.) adequate to protect the
integrity of finished water quality?
B-13
-------
DEFINITIONS FOR ASSESSING PERFORMANCE LIMITING FACTORS (cont.)
CATEGORY EXPLANATION
E. MISCELLANEOUS The "miscellaneous" category allows addition of factors not
covered by the above definitions. Space is available in the
Checklist to accommodate these additional items.
B-14
-------
c-i
APPENDIX C
Data Collection Forms
-------
Intentionally Blank Page
-------
FORMA
KICKOFF MEETING
A. MEETING OUTLINE
1. Purpose of CPE
a. Background surface dimensions
b. Assess plant potential for achieving compliance.
c. Identify current factors limiting performance.
d. Outline followup activities.
DAY TIME
2. Schedule of Events
a. Kickoff Meeting
b. Plant Tour
c. Review Budget/
User Charge
Ordinance/Revenues
d. Onsite Data Collection
Review O&M Manual/
Design Data/
Operating Records
e. Conduct Personnel
Interviews (see attached)
f. Exit Meeting
3. Information Resources (availability):
As-built construction drawings
O&M Manual
Monitoring records
Equipment literature
Process control records
Budget records
Design consultant
C-1
-------
FORM A (cont.)
KICKOFF MEETING
B. ATTENDANCE LIST
Municipality:
Date:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
NAME
TITLE/DEPT.
TELEPHONE NO.
C-2
-------
FORM A (cont.)
KICKOFF MEETING
C. PERSONNEL INTERVIEWS SCHEDULING SHEETS*
PERSON TITLE DAY TIME
'Includes offsite administrators/owners, budgeting personnel, laboratory personnel, maintenance personnel, plant
administrators, shift personnel, operators, etc.
-------
FORM B
ADMINISTRATION DATA
A. NAME AND LOCATION
Name of Facility
Owner
Administrative Office:
Mailing Address
Primary Contact
Title
Telephone No.
Treatment Plant:
Mailing Address
Primary Contact
Title
Telephone No.
C-4
-------
FORM B (cont.)
ADMINISTRATION DATA
B. ORGANIZATION
1. Governing Body (name and scheduled meetings):
2. Structure;
From Governing Body to Plant
Plant Staff
3. Staff Meetings (formal/informal):
C-5
-------
FORM B (cont.)
ADMINISTRATION DATA
B. ORGANIZATION (cont.)
4. Reporting Requirements (formal/informal):
5. Public Relations/Education:
6. Observations (openness, awareness of plant needs, management style, etc.):
C-6
-------
FORM B (cont.)
ADMINISTRATION DATA
C. PERSONNEL
PLANT
NO.
TITLE/NAME
% TIME AT
CERTIFICATION PAY SCALE PLANT
OFF SITE
NO.
TITLE/NAME
PAY SCALE
% TIME ALLOCATED TO
PLANT
D. TRAINING
Operator Training Budget
Training Incentives
Training Over Last Year_
C-7
-------
FORM B (cont.)
ADMINISTRATION DATA
PLANT COVERAGE
WEEKDAYS
Shifts (Times/Over!ap?/Number per shift):
Weekends and Holidays:
Alarms (On what process? Dialer?):
C-8
-------
FORM B (cont.)
ADMINISTRATION DATA
F. PLANT BUDGET/EXPENDITURES (Attach copy of actual budget and/or expenditures if available.)
Budget year to
Expenditure period to
CATEGORY BUDGET AMOUNT EXPENDITURE AMOUNT
Administrative Salaries (incl. fringes)
Plant Staff Salaries (incl. fringes)
Utilities
Electric (see attached summary)
Gas (see attached summary)
Chemicals
Vehicles
Training
Operations Subtotal
Capital Outlay (see attached summary)
Bond Debt Retirement
Reserve
Capital Improvement Subtotal
TOTAL
Observations;
-------
FORM B (cont.)
ADMINISTRATION DATA
G. CAPITAL OUTLAYS
1. BOND RETIREMENT
Bond Type Year Issued
Duration Interest Rate
Annual
Payment
Description of Project Financed
2. Capital Improvement Reserve (Self sustaining utility? master plan? exceed bond requirements?
replacement philosophy?)
3. Capital Replacement Plan (Available? Items scheduled for replacement? Attach if available.)
4. Expansion History and Proposed Modifications (historical studies, current evaluations,
long-range plans, etc.)
C-10
-------
FORM B (cont.)
ADMINISTRATION DATA
H. REVENUE
1. USER CHARGES
a. Demand Charge
Residential
5/8"
Commercial/Industrial
5/8"
3/4"
1"
1 1/2"
2"
21/2"
3"
Special Users
b. Commodity Charge
2. CONNECTION FEE FEE
Type of Connection
Residential
5/8"
Commercial/Industrial
5/8"
3/4"
1"
1 1/2"
2"
2 1/2"
3"
Special Users
3. Other Sources of Revenue (interest income, bulk water sales):
RATE
RATE
C-11
-------
FORM B (cont.)
ADMINISTRATION DATA
4. Total Revenue for Evaluation Period (compare to expenditures):
5. Miscellaneous:
Are rates and budgets reviewed annually?
When was last rate increase? (How much?)
Proposed increases?
C-12
-------
FORM C
DESIGN DATA
A. PLANT FLOW DIAGRAM (Attach if available; include solids handling and chemical feed points.)
B. FLOW DATA
Design Flow
Average Daily Flow mgd x 3,785= m3/d
Maximum Hydraulic Capacity mgd x 3,785= m3/d
Operating Flow
Peak Instantaneous Operating Flow mgd x 3,785= m3/d
C-13
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES
FLOW MEASUREMENT
Flow Stream Measured Meter Type Calibration Frequency Comments
Raw Water:
Finished Water:
Backwash:
Backwash Recycle:
Other (designate):
Accuracy Check during CPE (describe):
C-14
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.)
SCREENING
Traveling Bar Screen:
Bar Screen Width inch x 2.54= cm
Bar Opening inch x 2.54= cm
Screening Disposal:
Operation Problems:
Hand Cleaned Bar Screen:
Bar Screen Width inch x 2.54= cm
Bar Spacing inch x 2.54= cm
Cleaning Frequency
Screening Disposal:
Operation Problems:
Other (describe):
C-15
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.)
PUMPING
Flow Stream Pumped Type No. of Pumps Rated Capacity
Flow Control Method (describe):
Flow Stream Pumped Type No. of Pumps Rated Capacity
Flow Control Method (describe):
Flow Stream Pumped Type No. of Pumps Rated Capacity
Flow Control Method (describe):
Flow Stream Pumped Type No. of Pumps Rated Capacity
Flow Control Method (describe):
C-16
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.)
Presedimentation:
PRESED1MENTATION
Type (concrete or earthen sketch below):
Number of Basins
Water Depth (shallowest^
Water Depth (deepest)
Weir Location
Weir Length
Total Surface Area_
Total Volume
Total Volume
Flow:
(Design),
(Operating)*.
Detention Time:
(Design)
Weir Overflow Rate:
(Design)
(Operating).
Surface Settling Rate:
(Design)
(Operating),
Chemical Feed Capability:
Type of Chemicals
Operating Range (describe):
Sketch:
_Surface Dimensions
ft x 0.3 =
ft x 0.3 =
ft x 0.3 =
sq ft x 0.093 =
cu ft x 0.028 =
mg
mgd x 3,785 =
mgd x 3,785 =
_ hr (Operating)*
.gpm/ftx 17.88 =
.gpm/ftx 17.88 =
.gpm/ft2 x 58.7 =
. gpm/ft2 x 58.7 =
m
m
m
2
m
nr
_m3/d
m3/d
hr
_m3/m/d
m3/m/d
_m3/m2/d
m3/m2/d
*Peak instantaneous operating flow.
C-17
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.)
Rapid Mix:
RAPID MIX
Type,
(mechanical, inline mechanical, inline static)
Number of Mixers
Number of Basins
Water Depth
Horsepower
Total Volume
_Surface Dimensions
ft x .3 =
cu ft x 0.028 =
gallons
m
m
Flow:
(Design)
(Operating)*
mgd x 3,785 =
mgd x 3,785 =
_m3/d
m3/d
Detention Time:
(Design)
(Operating)
G Value (see attached sheet):
(Design)
(Operating)
_sec
sec
sec
sec
-1
Operating Problems:
*Peak instantaneous operating flow.
C-18
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.)
Calculation of G Value:1
e-f-f
I LL V
V. /
in which G = velocity gradient in sec'1
P = power input in ft lb/sec
;• = viscosity in lb sec/ft2
V = volume in ft3
For example:
Calculate G for an inline mixer with:
.75 hp, 1.5 mgd flow, water temp. = 8 °C.
Assume detention time in mixer = 0.4 sec.
Power Input = .75 hp x 550 ft/lb/sec hp = 412.5 lb/sec.
Volume Treated = 1.5 mgd x 1.547 cfs/mgd = 2.32 cfs.
Volume to which power is supplied at residence time of 0.4 sec.
V = 2.32 cfs x 0.4 sec = 0.93 ft3.
Viscosity @ 8 °C = 2.90 x 10"5 lb sec/ft2.
f P1
V2
( 412.5
Li V
2.90x10 5x0.93
V /
\
Viscosity of Water vs Temp.2:
TEMP. °F
TEMP. °C
VISCOSITY
y. x 10"5
Ib-sec/ft2
32
0
3.746
40
4
3.229
50
10
2.735
60
16
2.359
70
21
2.050
80
27
1.799
90
32
1.595
100
38
1.424
1Sanks, Robert, L., Water Treatment Plant Design, Ann Arbor Science Publishers, 1978.
2From "Hydraulic Models," A.S.C.E. Manual of Engineering Practice, No. 25, A.S.C.E., 1942.
C-19
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.)
FLOCCULATION
Flocculation:
Type (e.g., paddle wheel, turbine, hydraulic)
Control (e.g., constant speed or variable speed)
Stages (sketch below):
SURFACE
STAGE/BASIN DIMENSIONS DEPTH VOLUME HORSEPOWER G VALUE
1 ~
2
3
4
Total
Flow:
(Design)
(Operating)*
Detention Time:
(Design)
(Operating)
Operating Problems:
MGD x 3,785=
MGDx 3,785=
,min
min
m3/d
m3/d
Sketch:
*Peak instantaneous operating flow.
C-20
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.)
„ „ . SEDIMENTATION
Sedimentation Basins:
Number of Basins Surface Dimensions
Water Depth (Shallowest) ft x 0.3= m
Water Depth (Deepest) ft x 0.3= m
Weir Location
Weir Length ft x 0.3= m
Total Surface Area sq ft x 0.093= m2
Total Volume cu ft x 0.028= m3
Total Volume mg
Flow:
(Design) MGDx 3,785= m3/d
(Operating)* MGD x 3,785= m3/d
Detention Time:
(Design) hr (Operating) _hr
Weir Overflow Rate:
(Design) gpm/ft x 17.88= m3/m/d
(Operating) gpm/ft x 17.88= m3/m/d
Surface Settling Rate:
(Design) gpm/sq ft x 58.7= m3/m2/d
(Operating) gpm/sq ft x 58.7= _m3/m2/d
Inlet Conditions (Describe and/or sketch):
Operating Problems:
*Peak instantaneous operating flow.
C-21
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.) FILTRAT10N
Type of Filters (sand, mixed media, dual media, pressure gravity, etc.)
Number of Filters Surface Dimensions
Media Characteristics: UNIFORMITY EFFECTIVE
MEDIA TYPE DEPTH (in.) COEFFICIENT SIZE
Total Surface Area ft2 x 0.093=
Filtration Rate:
(Design) gpm/ft2 x 58.7=
(Operating) gpm/ft2 x 58.7=
Filter Control (e.g., constant rate, declining rate, constant level, etc.):
Available Headloss ft x 0.305=
Surface Wash:
Type (e.g., rotary, fixed, manual)
Water Flow Rate gpm x 0.23=
Surface Wash Rate gpm/ft2 x 58.7=
Duration (Operating) min
Backwash:
Water Wash Rate:
(Design) gpm/ft2 x 58.7=
(Operating) gpm/ft2 x 58.7=
Duration:
(Design) min (Operating) _
Air Wash Rate:
(Design) scfm/ft2 x 0.3= _
(Operating) scfm/ft2 x 0.3= _
C-22
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.)
Control/Operating Problems:
Mud Balls:
Dirty Media:
Uneven Media:
Backwash Rate Control/Procedure (e.g., gradual start/stop):
Filter Rate Control/Procedure (e.g., gradual changes):
Hydraulic Loading during Backwash (e.g., reduce flow to remaining filters?)
Air Bubbles during Backwash:
Surface Wash Control/Procedure:
Other:
Availability of Sample Taps (e.g., backwash and individual filters):
C-23
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.)
DISINFECTION
Contact Basin(s) (e.g., clearwell): CHANNEL
SURFACE LENGTH TO
BASIN NO. DIMENSIONS DEPTH VOLUME WIDTH
Total Volume
Detention Time:
(Theoretical)'3'.
(b)
min
min
(Functional)
(a) Detention time based on total available volume and peak instantaneous operating flow.
(b) Detention time based on evaluation of operating variables such as basin baffling, minimum
operating depth, and transmission line length to first user. Utilize the table below to determine
the factor to be multiplied by the actual volume to accommodate baffling consideration.
FACTORS TO DETERMINE EFFECTIVE VOLUME FROM ACTUAL VOLUME BASED ON BAFFLING
CHARACTERISTICS (REGLI)
Baffling Condition Factor
Unbaffled 0.1
Poor 0.3
Average 0.5
Superior 0.7
Excellent 0.9
Baffling Description
None, agitated basin, high inlet and outlet flow velocities,
variable water level.
Single or multiple unbaffled inlets and outlets,
no intrabasin baffles.
Baffled inlet or outlet with some intra-basin baffling; may be
used for existing floc/sedimentation basins when
calculating prechlorination.
Perforated inlet baffle, serpentine or perforated intrabasin
baffles, outlet weir or perforated weir.
Serpentine baffling throughout basin.
C-24
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.)
Chlorinator(s):
No. of Chlorinators
Capacity Ib/d x 0.454= kg/d
Flow Proportioned?
Feed Rate:
(Design) Ib/d x 0.454= kg/d
(Operating) Ib/d x 0.454= kg/d
Flow:
(Design) mgd x 3,785= m3/d
(Operating)* mgd x 3,785= m3/d
Dosage:
(Design) mg/L (Operating)* mg/L
Operating Problems:
*Peak instantaneous operating flow.
C-25
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.)
CHEMICAL FEED CAPABILITY
Coagulant Aids (Metal Salts):
Dry:
nccmM cccn OPERATING FLOW DESIGN DOSAGE*
DESIGN FEED (MGD, m3/d) (mg/L)
RANGE (i.e., Ib/hr,
TYPE Kg/h) min. max. nnin.
max.
Liquid:
ncc,rK, rrrn OPERATING FLOW DESIGN DOSAGE*
n a Mr r r h (MGD-m3/d} (mg/L)
RANGE (i.e., gph, - -
TYPE mLVmin min. max. min. max.
Dosage Control (describe):
Operating Problems:
Accuracy Check during CPE (describe):
Typical Liquid Coagulant Characteristics:
TOTAL
Alum
Ferric Chloride
Ferric Sulfate
lb/gal
11.1
11.2
12.3
*Comparo to desired dosage range.
COAGULANT
kg/L lb/gal kg/L
1.33
1.34
1.47
5.4
3.4
6.2
0.65
0.41
0.74
PERCENT
COAGULANT
(%)
49
30
50
DESIRED
DOSAGE
RANGE (mg/L)
0- 100
0 - 50
0-50
C-26
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.)
Polymers:
TYPE PURPOSE8
DESIGN
FEED
RANGE
(gpn,
mLVmin)
OPERATING
FLOW (MGD,
m3/d)
mm.
max.
CONCd
NEAT
(lb/gal,
kg/L)
RECOMM.c
DILUTION
(%)
DESIGN DOSAGE
(mg/L)
min.
max.
ae.g., coagulant, flocculant, or filter aid.
"Obtain from manufacturer's data sheet. May range from 1.0 kg/L (8.5 lb/gal) to 1.7 kg/L (14 lb/gal).
cObtain from manufacturer's data sheet. May range from 0.1% to 2%.
Dosage Control (describe for each):
Operating Problems:
Accuracy Check during CPE (describe):
C-27
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.)
Stabilization Chemicals:
Chemicals Used:
Dosage Control (describe):
Operating Problems:
Fluoride:
Fluoride Compound Used:
Dosage (Operating) mg/L
Comments:
Softening:
Chemicals Used:
Dosage Control (describe):
Operating Problems:
Recarbonation:
Carbon Dioxide Source (bottled CO2 or waste gas burner):
Dosage Control (describe):
Operating Problems:
Powdered Activated Carbon:
Dosage Control (describe):
Operating Problems:
C-28
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.)
SOLIDS HANDLING
Presedimentation Sludge:
Description of Pumping Procedure (i.e., time clocks, variable speed pumps):
Method of Waste Volume Measurement:
Sampling Location:
Sampling Procedure:
Operating Problems:
Sedimentation Sludge:
Description of Pumping Procedure (i.e., time clocks, variable speed pumps):
Method of Waste Volume Measurement:
Sampling Location:
Sampling Procedure:
Operating Problems:
C-29
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.)
SOLIDS HANDLING (cont.)
Return Sludge (Solids Contact Unit):
Description of Sludge Movement:
Controllable Capacity Range:
(Low)
(High)
mgd x 3,785=
mgd x 3,785=
m3/d
m3/d
Method of Control:
Sampling Location:
Sampling Procedure:
Operating Problems:
Sludge Drying Beds/Lagoons:
No. of Beds/Lagoons Dimensions
Total Volume Subnatant Drain to
Dewatered Sludge Removal:
Mode of Operation (depth of sludge draw, seasonal operation; include sketch):
Operating Problems:
C-30
-------
FORM C (cont.)
DESIGN DATA
C. UNIT PROCESSES (cont.)
SOLIDS HANDLING (cont.)
Other Dewatering Unit(s):
Type of Unit(s)
No. of Units
Loading Rate:
(Design) Ib/hr x 0.454= kg/h
(Operating) Ib/hr x 0.454= kg/h
Polymer Used
lb/dry ton x 0.5= g/kg
Cake Solids % Solids
Hours/Week of Operation:
(Design) _
(Operating)^
Operating Problems:
Ultimate Sludge Disposal:
Description:
Operating Problems:
C-31
-------
FORM C (cont.)
DESIGN DATA
D. MISCELLANEOUS DESIGN INFORMATION
Process Automation (describe existing systems):
Standby Units (chemical feed, backwash pumps):
Flow Proportioning to Units:
Alarm Systems (description of systems, units covered):
Alternate Power Source:
Weather Inope rability:
Return Process Streams:
C-32
-------
FORM D
OPERATIONS DATA
A. PROCESS CONTROL STRATEGY AND DIRECTION
Who sets major process control strategies and decisions?
Who makes process control decisions when lead process control person is not at plant?
Where is help sought when desired performance is not achieved?
Are staff members asked their opinions?
How is communication conducted among laboratory, operations, and maintenance?
B. SPECIFIC PROCESS CONTROL PROCEDURES
Sampling and Testing:
Sampling Locations (add to plant flow schematic):
Presedimentation:
Sludge Removal (method of control/adjustment):
Performance Monitoring:
Other:
C-33
-------
FORM D (cont.)
OPERATIONS DATA
B. SPECIFIC PROCESS CONTROL PROCEDURES (cont.)
Sedimentation:
Performance Monitoring (tests used; solids balance):
Sludge Removal (method of control/adjustment):
Sludge Recycle (contact sedimentation):
Other:
Filtration:
Hydraulic Loading Rate Control (method of control/adjustment):
Backwash Control (test used, method of determining frequency)
Filter Monitoring (turbidity, SCD, pilot filter, etc.):
• Influent Turbidity
• Effluent Turbidity
• Headioss
• Loading Rate
• Length of Run
Coagulation/Turbidity Removal:
Feed Rate Control (method of control/adjustment):
Performance Monitoring:
• Jar Test
• Pilot Filter
• Zeta Meter
• Streaming Current Detector
• Turbidity
C-34
-------
FORM D (cont.)
OPERATIONS DATA
B. SPECIFIC PROCESS CONTROL PROCEDURES (cont.)
Disinfection:
Performance Monitoring (tests used):
Feed Rate Control (method of control, adjustment):
Fluoridation:
Performance Monitoring (tests used):
Feed Rate Control (method of control, adjustment):
Stabilization:
Performance Monitoring (tests used):
Feed Rate Control (method of control, adjustment):
Softening/Recarbonation:
Performance Monitoring (tests used):
Feed Rate Control (method of control, adjustment):
C-35
-------
FORM D (cont.)
OPERATIONS DATA
B. SPECIFIC PROCESS CONTROL PROCEDURES (cont.)
Taste and Odor:
Performance Monitoring (tests used):
Feed Rate Control (method of control, adjustment):
Sludge Handling and Disposal:
Sludge Dewatering (monitored, process control/optimization):
Sludge Disposal (meet requirement, monitoring, options):
Other:
Miscellaneous:
Data Development/Interpretation:
Trend Charts:
C-36
-------
FORM D (cont.)
OPERATIONS DATA
C. PROCESS CONTROL REFERENCES
Specifically note sources (e.g., publications or personnel) that are the cause of poor process control
decisions or strategies, suspected or definitely identified):
D. OPERATIONS AND MAINTENANCE MANUAL
Adequacy:
Use:
C-37
-------
FORM D (cont.)
OPERATIONS DATA
E. LABORATORY CAPABILITY
ADEQUATE
1. Facilities
YES NO
Bench space
Storage space
Floor area
Lighting
Electricity .
Potable water supply
Compressed air
Vacuum
Chemical fume hood
Air conditioning
Desk
Records storage
AVAILABLE
2. Equipment and Instruments
YES NO
Turbidimeter
Core sampler
pH meter
Centrifuge
Distilled water (source)
Drying oven
FC water bath incubator
Coliform water bath incu.
Hot air oven
Refrigerator
Autoclave
Analytical balance
Microscope
Desiccator
Automatic samplers
Spectrophotometer
Atomic absorption
Gas chromatograph
Conductivity meter
Jar test apparatus
Titration burets
Erlenmeyer flasks
Volumetric flasks
C-38
-------
FORM D (cont.)
OPERATIONS DATA
E. LABORATORY CAPABILITY (cont.)
2. Equipment and Instruments (cont.)
Beakers
Evaporating dishes
Zeta meter
Particle counter
AVAILABLE
YES NO
3. Analytical Capability
Total Solids
Calcium
Magnesium
Hardness
Sodium
Alkalinity
Temperature
pH
Turbidity
Iron
Manganese
Chloride
Sulfate
Nitrate
Total Coliform
Heterotrophic plate count
Conductivity
Total dissolved solids
Trace inorganics
AVAILABLE
YES NO
Organics
C-39
-------
FORM D (cont.)
OPERATIONS DATA
E. LABORATORY CAPABILITY (cont.)
4. Miscellaneous
Quality Control:
EPA Reference Samples:
Duplicate Tests (schedule, records, etc.):
Standard Procedures/References:
Standard Methods:
Site-Specific Procedures:
Training:
C-40
-------
FORME
MAINTENANCE DATA
A. PREVENTIVE MAINTENANCE PROGRAM
Program Description:
Method of Scheduling;
Method of Documenting Work Completed:
Method of Factoring Costs for Parts/Equipment into Budgeting Process:
Spare Parts Inventory:
References:
O&M Manual:
Accurate Record Drawings:
Manufacturer's Literature:
Adequacy of Resources Available:
Outside Support:
Tools/Lubricants:
Work Area:
C-41
-------
FORM E (cont.)
MAINTENANCE DATA
B. EMERGENCY MAINTENANCE PROGRAM
Priority Setting (relationship to process control decisions):
Extent of Onsite Capability:
Method of Initiating Work Activities (work order):
Critical Parts Procurement (policy restrictions, sources):
Comments:
C-42
-------
FORM E (cont.)
MAINTENANCE DATA
C. GENERAL
Equipment or Processes Out of Service Due to Breakdowns (Identify equipment or process,
description of problem, length of time out of service, what has been done, what remains to be done,
estimated time before repair, how the situation affects performance):
During the CPE (list and explain):
During the Last 12 Months (list and explain):
C-43
-------
FORM F
PERFORMANCE DATA
A. SOURCE OF DATA
B. FLOW DATA
FLOW
mm.
avg.
max.
OPERATING
TIME
INS. PEAK
OPERATING
FLOW*
Units
mo/yr
Avg.:
Peak:
'Instantaneous peak operating flow is the peak flow rate that the unit processes achieve on a sustained basis.
For example, if a plant treats 500,000 gpd (350 gpm) in a 12-hour period, then the instantaneous peak
operating flow would be 500,000 gallon/day x 24 hr/12 hr = 1.0 mgd (700 gpm). Judgment of the
evaluator is essential in selecting the instantaneous peak operating flow because of variations in flow that
can occur by operating different pumps or changing unit processes that are in service.
C-44
-------
FORM F (cont.)
PERFORMANCE DATA
C. DEMAND EVALUATION
Number of Taps Served Population Served
Major Industrial Users (include name and volume used):
Per Capita Consumption:
Average:
Peak:
Typical per capita water consumption values are shown below:
Type of Consumption
Lpcd
gpcd
Lpcd
gpcd
Domestic or Residential
76-340
20-90
208
55
Commercial
38-492
10-130
76
20
Industrial
76-303
20-80
189
50
Public
19-76
5-20
38
10
Water Unaccounted for
19-114
5-30
57
15
227-946
60-250
568
150
Source: G.M. Fair, J.C. Geyer, and D.A. Okun, Elements of Water Supply and Wastewater
Disposal, 2nd ed. New York, NY: Wiley, 1971.
D. UNACCOUNTED FOR WATER EVALUATION
Total production of water treatment plant mg or m3
Total metered water mg or m3
Difference
% unaccounted = Difference— x100
Total Production
%
Note: Typical unaccounted for water is 10%.
C-45
-------
FORM F (cont.)
PERFORMANCE DATA
E. BACKWASH WATER EVALUATION
Total volume of filtered water mg or m3
Q
Total volume of backwash water mg or m
Difference
% BW Water = D|fference x100
Total Volume of Filtered Water
Note: Typical amount of backwash water is 2% to 6% for conventional plants. Direct filtration plants
often exceed this depending on raw water quality.
F. RAW WATER QUALITY
TURB.
TOTAL
min. avg. max. TEMP. pH HARD. ALK.
Units
mo/yr
Avg.:
C-46
-------
FORM F (cont.)
PERFORMANCE DATA
G. REPORTED OPERATING DATA FOR PREVIOUS 12 MONTHS
SETTLED WATER FINISHED WATER
TURB. TURB.
min. avg. max. min. avg. max.
Units
mo/yr
Avg.:
C-47
-------
FORM F (cont.)
PERFORMANCE DATA
H. CHEMICAL CONSUMPTION
Type of Chemical
Unit Cost
CHEMICAL USE
PER MONTH
{gallons or
MONTH/YEAR lbs/month) COMMENTS
Total
Type of Chemical
Unit Cost
CHEMICAL USE
PER MONTH
(gallons or
MONTH/YEAR lbs/month) COMMENTS
Total
C-48
-------
FORM F (cont.)
PERFORMANCE DATA
I. PERFORMANCE ASSESSMENT
Develop graphs to depict plant performance. Possibilities are:
1. Plant effluent turbidity versus time for weeks or months with maximum recorded turbidities.
Isolate shorter time frames on graph after reviewing data.
2. Filter effluent turbidity versus time to assess recovery time following backwashing a filter or
starting a dirty filter.
3. Probability plots to show percentage of time turbidity exceeds 0.5 NTU standard.
4. Long-term plots of raw water and finished water turbidities to assess process control.
5. Long-term plots of finished water turbidity to assess stability of operation.
J. PERFORMANCE VIOLATIONS WITHIN LAST 12 MONTHS:
C-49
-------
FORM G
INTERVIEW DATA
A. INTERVIEW CONCERNS
Interviews are used to obtain feedback in the four categories of administration, design, operation,
and maintenance. The following items are presented to assist the interviewers in obtaining
this feedback.
1. Administration
Owner Responsibility
• Attitude toward staff?
¦ Attitude toward regulatory agency?
• Self-sustaining facility attitude?
• Attitude toward consultants?
• Policies?
¦ Communications (formal/informal)?
Performance Goal
• Is plant in compliance?
• If yes, what's making it that way?
• If no, why not?
• Is regulatory pressure felt for performance?
• What are performance requirements?
Administrative Support
¦ Budget
• Within range of other plants?
¦ Covers capital improvements?
¦ "Drained" to general fund?
• Unnecessary expenditures?
• Sufficient?
• Attitude toward rates?
Personnel
• Within range of other plants?
• Allows adequate time?
• Motivation, pay, supervision, working conditions?
• Productivity?
• Turnover?
• Training support?
Involvement
• Visits to treatment plant?
• Awareness of facility performance?
¦ Request status reports (performance and cost-related)?
• Familiarity with plant needs?
C-50
-------
FORM G (cont.)
INTERVIEW DATA
A. INTERVIEW CONCERNS (cont.)
2. Design
• Raw water quality problems?
• Equipment problems?
¦ Status of warranties?
« Return process streams?
• Preliminary treatment?
• Coagulation/flocculation?
• Sedimentation?
• Filtration?
• Chemical feed?
• Softening?
• Advanced treatment techniques?
• Disinfection?
• Sludge handling and disposal?
• Flow measurement?
• Flow splitting?
• Alarms or alternate power?
3. Operation
• Communication of decisions?
¦ Key control parameters?
• Involvement of staff?
• Laboratory quality?
• Administrative support?
• Staffing?
• Performance problems?
• Unit process optimization?
• External support?
• Process control testing/adjustments?
• O&M Manual/references?
4. Maintenance
• How are priorities set?
• Attitude toward program?
• Emergency versus preventative?
• Reliability (spare parts or critical part procurement)?
• Staffing?
• Equipment assessibility?
C-51
-------
FORM G (cont.)
INTERVIEW DATA
B. PERSONNEL INTERVIEWS
Name:
Title:
Certification:
Years at Plant: Years of Experience:
Area of Responsibility:
Training:
Concerns/Recommendations (Administration, Design, Operation and Maintenance):
C-52
-------
FORM H
EXIT MEETING
ATTENDANCE LIST
Municipality: Date:
1.
2. _ _
3.
4.
5.
6 .
7 .
S
9.
10 .
11. _
12 .
13.
14.
15.
16.
17. _
18.
19.
20.
Attach Copy Of Exit Conference Handouts
C-53
-------
Intentionally Blank Page
-------
APPENDIX D
Sample CPE Scheduling Letter
-------
Intentionally Blank Page
-------
Chairman/Mayor
Public Service District/Town
RE: Evaluation of the Public Service District/Town Water Treatment Plant by U.S. EPA
and the State of May 8, 9 and 10,1990.
Dear Mr. :
Thank you for agreeing to participate in the above evaluation of the Public Service District/Town water
treatment plant. Mr. of the State of contacted you regarding your participation in this
evaluation. This letter is intended to provide you with some information on the evaluation and describe
the activities in which the Public Service District/Town will be involved.
This evaluation is a part of a U.S. EPA project to develop and demonstrate a procedure for evaluating
drinking water treatment plants. In the future there will be an increasing number of drinking water
regulations with which communities such as yours will have to comply. EPA is concerned with the
ability of small communities to comply with these regulations.
The evaluation procedure that will be used is the Composite Correction Program (CCP) approach. The
CCP approach, originally developed for wastewater treatment plants, has been successfully used to
bring these plants into compliance. In this project, we are evaluating water plants around the country
and using this information to adapt these CCP procedures to water treatment plants.
During this evaluation, all aspects of the design, operation, maintenance, and administration of
the Public Service District/Town water treatment plant will be reviewed and evaluated with
respect to their impact on performance. By evaluating the Public Service District/Town plant,
EPA will gain some valuable experience using the CCP procedures in the "real world" and
Public Service District/Town should have a good understanding of where their plant stands with respect
to compliance with current and future regulations.
The evaluation will begin with a brief entrance meeting on Tuesday, May 8,1990, at approximately 8:30
A.M. The purpose of the entrance meeting is to discuss with the operations staff and plant
administrators the purpose of the evaluation and the types of activities that will occur during the 3 days.
Any questions and concerns regarding the evaluation also can be raised at this time. It is important that
the plant administrators and those persons responsible for plant budgeting and planning be present
because this evaluation will focus a significant effort in reviewing these aspects of the plant. Following
the entrance meeting, which should last approximately 30 minutes, the plant staff will be requested to
take the evaluation team on an extensive plant tour. After the plant tour, the team will begin collecting
performance and design data. Please make arrangements so that the operating records and any
design information for the plant are available.
On the second day, the evaluation team will be involved in several different activities. The major
involvement of the plant staff during the second day will be in interviews with each of the plant staff.
The plant administrators will also be interviewed and the financial records of the plant reviewed.
Several special studies may also be completed by the evaluation team to investigate the performance
capabilities of the plant's different unit treatment processes. We request that each of the operations
staff be available sometime during the second day for the interviews. We would also appreciate having
some staff members available to answer questions about the plant and operate the plant during the
special studies. We will be flexible in scheduling these interviews and special studies around other
D-1
-------
required duties of you and your staff. Specific times will also need to be arranged for interviews with
the key administrators of the plant. Key financial records and plant budget should be available to the
evaluation team.
We will need to review the monitoring reports that were sent to the State of for the last 12
months. Any laboratory and plant log sheets covering this same period also will be useful as well as
any drawings and specifications for the treatment plant. We also will need budget and financial
information for the Public Service District/Town. This will center around the budget for the treatment
plant and information on salaries, outstanding bonds, operating funds available, etc. It is our
experience that the information we need is usually readily available from existing reports. We usually
work with the information available and do not request that administrative staff prepare additional
summaries of the information. The special studies will require taps on the piping from each filter so that
we can obtain samples of the finished water from the individual filters.
The last day of the evaluation will consist of an exit meeting. During the exit meeting, the results of the
evaluation will be discussed with all of those who participated. The performance capabilities of the
treatment processes will be presented and any factors found to limit the performance of the plant will be
discussed. The evaluation team will also "answer any questions regarding the results of the evaluation.
The results presented in the exit meeting will form the basis of the final report, which will be sent to the
State of in about one month. We tentatively expect to begin the exit meeting at 7:30 A.M. on
Thursday, May 10, 1990, and it should last approximately an hour. We may change this time
depending on how the evaluation proceeds.
The evaluation team will consist of six persons, two will be from Process Applications, Inc. of Fort
Collins, Colorado; two from U.S. EPA, Cincinnati, Ohio; and two from the State of . The size of
this team is larger than normal for this type of evaluation because as part of this project we are also
trying to demonstrate to several members of the team how this approach is used in the field.
Thank you again for allowing us to evaluate the Public Service District/Town plant. I believe that
the Public Service District/Town will find the results of this evaluation valuable in achieving
compliance with present and future drinking water regulations.
Sincerely yours,
D-2
-------
APPENDIX E
Sample CPE Report
-------
Intentionally Blank Page
-------
RESULTS OF THE
COMPREHENSIVE PERFORMANCE EVALUATION
OF WATER TREATMENT PLANT NO. 19
E-1
-------
MAILING ADDRESS:
SITE VISIT INFORMATION
DATE OF SITE VISIT:
CITY PERSONNEL:
CPE TEAM:
E-2
-------
TABLE OF CONTENTS
PAGE NO.
Introduction 4
Facility Information 4
Major Unit Process Evaluation 6
Performance Assessment 8
Performance-Limiting Factors 10
Projected Impact of a CPE 13
References 13
LIST OF FIGURES
PAGE NO.
Figure 1. Plant No. 19 Schematic 5
Figure 2. Plant No. 19 Performance Potential Graph 7
Figure 3. Raw Water Turbidity Versus Time 9
Figure 4. Percentile Plot of Raw Water Turbidity 9
Figure 5. Finished Water Turbidity Versus Time 10
Figure 6. Probability Plot of Filtered Water Turbidity 11
Figure 7. Filter "CH Turbidity during CPE 11
Figure 8. Filter "C" Turbidity after Backwash 12
E-3
-------
INTRODUCTION
FACILITY INFORMATION
The Composite Correction Program (CCP) approach is a
proven procedure for improving the performance of
wastewater treatment plants (1). This approach consists
of two aspects, the Comprehensive Performance Evalua-
tion (CPE) and the CCP. A CPE is a thorough evaluation
of an existing treatment plant resulting in a comprehen-
sive assessment of the unit treatment process
capabilities and the impact of the operation, main-
tenance, and administrative practices on the optimal per-
formance of the plant. A CCP is used to optimize
performance of an existing plant by systematically ad-
dressing the factors limiting performance identified during
the CPE.
U.S. EPA's Office of Drinking Water (ODW) has been
given the responsibility by Congress of regulating the
nation's water systems to assure that they produce drink-
ing water that protects the public's health. To meet this
objective, a large number of drinking water regulations
will be promulgated and all public water systems will be
expected to comply. EPA has concerns that the public
water systems, especially the small ones, will not have
the technical and financial resources to comply. The
Agency, therefore, is looking for cost-effective methods to
achieve compliance. Given the success of the CCP ap-
proach in achieving compliance in existing wastewater
plants, interest was expressed in the potential for
developing a similar approach for water plants.
The State of Montana initiated a program to use the CCP
approach to evaluate water treatment plants using sur-
face supplies (2). The State found that CPEs clearly as-
sessed the public water system's capabilities to comply
with drinking water regulations. On several occasions,
improvements in performance occurred without a formal
followup CCP. Two plants where CCPs were imple-
mented showed sustained improvements in performance
to levels well within the turbidity levels required by the
new regulations.
Based on the initial success of the Montana program,
EPA decided to further develop and demonstrate the ap-
proach to ensure its applicability to other parts of the
country. A cooperative project was initiated between
EPA's ODW and the Office of Technology Transfer and
Regulatory Support (OTTRS), Center for Environmental
Research Information (CERI). This project is intended to
expand the experience base with the approach through
conducting additional CPEs and CCPs throughout the
United States and documenting the procedures in a
handbook.
As part of this project, a CPE was completed at Plant No.
19. The following report documents the findings of this
CPE.
The City uses a conventional treatment plant to treat
water supplied from the Piney Dam Watershed reservoir
and ground water supplied from several sources around
Savage Mountain. The plant supplies water for domestic
use to the City which has a population of approximately
7,800 and a college with an enrollment of approximately
4,500. The plant operates 24 hours per day. Figure 1
shows a schematic of the plant.
The Piney Dam Watershed reservoir provides most of the
raw water to Plant No. 19. At the time of the CPE, a new
dam and raw water pump station was under construction
to increase the capacity of the reservoir and ensure a
reliable supply of water to the City. During this construc-
tion, the old dam, reservoir, and pump station continued
in operation. This CPE deals with the old equipment at
the reservoir. The Piney Dam Watershed reservoir con-
sists of:
• A concrete dam with spillway forming a 55 million gal
reservoir.
• An intake structure that takes water from two levels in
the reservoir. Equipped with a hand-cleaned screen.
• A pump station with two multi-stage horizontal split
case centrifugal pumps; one rated at 975 gpm and the
other at 400 gpm.
Raw water is also supplied from several ground-water
sources around Savage Mountain, which are collected
and pumped to the plant by the Savage pump station.
The sources consist of:
• Twenty-three shallow springs at various locations
around Savage Mountain.
• Two spring collection sumps.
• Two deep wells each with a turbine pump limited to a
total production of 100,000 gpd by state permit. Each
has a separate propeller flow meter.
• A pump station with wet-well and two multi-stage
horizontal split case centrifugal pumps, each rated at
500 gpm.
• A 1,000,000 gal supply reservoir.
• A deep well with turbine pump that discharges a maxi-
mum of 35,000 gpd to the supply reservoir.
• A deep well with turbine pump rated at 92 gpm that
discharges into the treatment plant.
The surface, spring, and well raw water sources combine
before entering the water treatment plant.
Plant No. 19 was built in and upgraded in 1972. It
consists of:
• A 6 x 4.350 in. venturi raw water flow meter with
totalizer/recorder.
E-4
-------
Figure 1. Plant 19 schematic.
Big Piney Dam
intak* Structure
E7
Pump Station
Dmp W«u*
By—pOM
Urte
votve
AJum
Umo
Chlarfna
0—p Wells
Supply
Reservoir
O" -• Pump*
Spring Water
Collection Sumps
Discharge to River
A
i Backwash Water St Sludge
i Settled Water
Tube Settlers
r ->
Flocculation/Sedimentation
Basin
i
i
i
I
*+-
*H*,> -
<-1
Dual Media Rlters
Savage Pump
Station
Upper
Lower
Pump
" " A
Spring Houses
(23 Total)
A
Backwash
Pump
f
<>
Uncovered Storage J,
Reservoirs
J
-Oilortn#
To Distribution System
• Two volumetric feeders, one each for alum and lime.
• A gas chlorinator fed from a 150-lb cylinder for pre-
chlorination.
• A 30 ft by 50 ft flocculation/sedimentation basin con-
taining the following sections:
• A 6,730 gal baffled hydraulic flocculation section.
• A 3,370 gal unbaffled hydraulic flocculation section.
• A 26,100 gal flocculation section with mechanical
flocculator.
• A conventional sedimentation section, 15 ft deep
with 685 ft2 of surface area.
• A tube settler sedimentation section, 9 ft 3 in. deep,
equipped with 600 ft2 of 60° tube settlers and a
mechanical sludge collector.
• Four 9 ft by 10 ft dual media filters with 12 in. of sand
and 18 in. of anthracite.
• A 1,350 gpm horizontal split case centrifugal back-
wash pump.
• Two circular uncovered finished water storage reser-
voirs. One is 100 ft in diameter with 1,000,000 gal
capacity and the other is 164 ft in diameter with
3,600,000 gal capacity.
• Two gas chlorinators fed from separate 150-lb
cylinders, one for chlorination ahead of the finished
water reservoirs and the other for chlorinating the
finished water as it enters the distribution system.
• A 10-in. propeller meter located after the finished
water storage reservoirs to measure finished water
flow into the distribution system.
• A gravity fed distribution system.
The Piney Dam reservoir typically supplies most of the
raw water to the treatment plant and is supplemented
with water from the springs at Savage Mountain. No
E-5
-------
separate flow measurement is provided so the relative
amount of flow from each of these sources is not known.
Three of the four deep wells represent only a minor
source of raw water since their capacity is limited by
permits from the state. The fourth well at the plant can
only operate for 24 hours and then has to be shut down
for several days for recharge. After being pumped at
Piney Dam and Savage pump station, the water flows
by gravity to the supply reservoir, the plant, and
through the distribution system. The city has no high
service pumping.
At Piney Dam only the 975 gpm pump is normally used.
The other pump is only used as a standby since it can
not provide sufficient flow to the plant. Flows from Piney
Dam are controlled to allow as much water as possible to
be obtained from the 23 springs at the Savage pump sta-
tion. Water from the springs is collected and piped to one
of the two spring collection sumps. One of these sumps
is designated the "lower" sump and the other the "upper"
sump. Water from the "lower" sump is pumped to the
"upper" sump and then flows by gravity to the wet well in
the pump station. A level control system activates the
pump between the two collection sumps and the pumps
in the pump station. Flow from the two deep wells ad-
jacent to the pump station also discharge into the wet
well. A flow meter on each well is used to monitor the
amount of flow from the wells that is regulated by the
state. The well pumps are operated manually. During the
CPE only one of the 500 gpm pumps was installed and in
operation. A new pump was available, but not yet in-
stalled.
Water from the Piney Dam and Savage pump stations
combines before flowing to the plant. The supply reser-
voir, located just uphill from the plant, can be used to
equalize raw water flows by allowing it to either enter or
bypass around the supply reservoir. Normally most of the
raw water bypasses the reservoir flowing directly to the
plant. Water from the reservoir flows by gravity to the
plant.
Upon entering the plant, the raw water flow is measured
with the venturi flow meter. Alum and lime solutions,
prepared in mixing tanks beneath the volumetric feeders,
are added by gravity just after the flow meter. The pre-
chlorine is also added at this point. Jar tests are per-
formed periodically to set chemical dosages. Volumetric
feeders have been calbrated so that changes in timer
settings are correlated to chemical feed rates. Lime feed
is generally held constant with alum dose changed as
raw water turbidity changes. During the CPE, the alum
dose rate was measured at 40 mg/L and lime dose rate
at 34 mg/L. Prechlorination dose rates are set to maintain
a residual of 0.7 mg/L on top of the filters.
After chemical addition, the water enters the baffled
hydraulic flocculation section of the flocculation/sedimen-
tation basin. This section of the basin was originally
designed with 18 baffles that direct the flow up and down
as it proceeds through this section of the basin. Some of
these baffles have been removed. From this section, the
flow enters a second unbaffled hydraulic flocculation sec-
tion before flowing into the mechanical flocculation sec-
tion. During the CPE, the mechanical flocculator was not
operational. After flocculation the water flows into the two
sedimentation sections of the floc/sed basin. The first
provides conventional sedimentation and is followed by
the second tube settler sedimentation section. Sludge
from the conventional sedimentation section is removed
manually while a mechanical sludge collection
mechanism is located beneath the tube settlers.
Clarified water flows from the tube settlers to the dual
media filters. Three of the four filters are normally used
with the fourth left idle after backwash. Flows through
the filter are controlled manually by observing the water
levels in the filters. Rate of flow controllers are available,
but are in a poor state of repair, No flow measurement for
the individual filters is available. Each filter has a head-
loss gauge, but the units were working on only two of the
filters. The filters are backwashed using water from the
finished water storage reservoirs. The single backwash
pump was designed to backwash a single filter. As an
energy conservation measure, two filters are normally
washed at the same time. Sludge and backwash water
are discharged directly to a stream adjacent to the plant.
The state has issued a discharge permit to the city with
limits that will likely require construction of a sludge treat-
ment and disposal system by November 1990.
Finished water flows from the filters to the uncovered
finished water storage reservoirs, which can only be
operated in parallel. The water flows from the reservoirs
to the distribution system by gravity. A flow meter
measures the finished water flow cut the reservoir.
Chlorine is added to finished water before the reservoirs
and before entering the distribution system. A chlorine
residual of 0.2 mg/L is targeted to be maintained in the
reservoir and a residual of 0.8 mg/L is targeted for water
entering the distribution system. There is some difficulty
in maintaining the desired residual in the reservoirs be-
cause they are uncovered.
MAJOR UNIT PROCESS EVALUATION
Major unit processes were evaluated with respect to their
capability to consistently produce a finished water quality
of 0.5 NTU, which will be required by future regulations.
Overall plant capability was then assessed using a per-
formance potential graph where the projected treatment
capacity of each major unit process was compared to the
current peak average daily operating flow.
The performance potential graph developed for Plant No.
19 is shown in Figure 2. The unit processes evaluated
-------
Figure 2. Plant No. 19 performance potential graph.
F]occjI at i on
HDT Cmtn)
5ed f merit at 1 on 2
SOR Cgpm/'ftZ)
Filtration 3
Rate Cgpm/ft2)
Dis infect i on
Pre & Post''
HDT (m i n)
Post 5
HDT (m I n)
.5
H-
FIouj (mgd)
1.5 2
1— 1—
2.5
104
52|
35
2G 21
1
0.3
0.5l
0.8
1
1.0
2.0'
3.0
1590 7941 529 397 317 2G5
1320 GB2i 44Z 331
Peak Rverage Daily
Flow Rate - 764 gpm
3.5
—H Rated Capacity
2.G1 mgd 1810 gpm
2.0 mgd 1390 gpn
2.0 mgd 1330 gpm
3.3 mgd 2230 gpm
2.2 mgd 1530 gpm
H
Comments
1: Rated at 20 min HDT - multiple stages.
2: Rated at 1.1 gpm/ft2 combined SOR,-0.6 gpm/"ft2 conven.,1.5 gpm-'ftS tube set.
3: Rated at 4 gpm/ft2 - Dual madia.
4: Based on 4 log total reduction (S9.99X), 2.5 leg in plant, 1.5 log by prekpost
disinfection, pre based on CT™121 with 1 mg/L C12 residual, pH 7.5, temp 0.5 C,
505C useable floc/scd volume for contact; post based on CT=119 with 0.4 mg/L C12
residual, pH 7.5, temp 0,5 C, 10^ useable reservoir volume for contact.
5: Based on 4 log total reduction, 2.5 log in plant, 1.5 log by post disinfection;
based on CT~119 with 0.4 mg/L CI2 residual, pH 7.5, temp 0.5 C, 10'/. useable
reservoir volume for contact.
* Assumes adequate structural integrity of tanks.
are shown on the left side of the graph and the various
flow rates against which the processes were assessed
are shown across the top. Horizontal bars on the graph
represent (he projected peak capacity of the unit proces-
ses that would support achievement of the desired plant
performance of less than 0.5 NTU. These capacities
were projected based on the combination of treatment
processes at the plant, the CPE team's experience with
other similar processes, and industry guidelines. The
shortest bar represents the treatment process limiting
plant capacity relative to achieving the desired plant per-
formance.
The peak average daily operating flow rate for Plant No.
19 was established at 1.1 mgd. This is based on a review
of flow records for the previous year. The plant operates
24 hours per day.
The capacity of the three flocculation sections were rated
at 2.6 mgd. This rating was based on a 20-minute
hydraulic detention time (HDT) through all three sections.
Though the mechanical flocculators were not in opera-
tion, the CPE team felt that the multiple stages available
in this basin would allow the unit to provide adequate
hydraulic flocculation.
The sedimentation sections of the basin were rated at a
capacity of 2.0 mgd. These ratings were based on a sur-
face overflow rate of 1.1 gpm/ft for the combined con-
ventional and tube settler sections. This combined
surface overflow rate was based on a value of 0.6
gpm/ft2 for the conventional section and a value of 1.5
gpm/ft2 for the tube settler section.
Filtration capacity was rated at 2.0 mod. These capacities
were based on filter rates of 4 gpm/ft for the dual media
filters.
Future drinking water regulations for disinfection will be
based on CT values needed for inactivation of Giardia
cysts and viruses. CT is the disinfectant concentration
multiplied by the actual time the finished water is in con-
tact with the disinfectant. To establish the CT required, it
was assumed that the plant would have to provide a total
of 4 logs (99.99 percent) of cyst inactivation. It was also
assumed that the plant's treatment processes would
provide 2.5 logs of inactivation, requiring 1.5 logs of inac-
tivation by the disinfection system. The total of 4 logs of
cyst removal required for Plant No. 19 was based on the
CPE team's estimate of the quality of the water from the
Piney Dam Watershed reservoir. Higher total removals
are considered necessary for plants served by this type
of watershed because of the potential for greater cyst
concentrations caused by surface runoff.
Piant No. 19 adds chlorine at three locations, ahead of
the floc/sed basin, before the reservoirs, and following
the reservoirs before entering the distribution system.
For this assessment, only the first two points of chlorina-
tion, designated pre- and postchlorination, were con-
-------
sidered because of the short contact time provided in the
distribution system before the first customer.
To achieve 1.5 logs of cyst inactivation with both pre- and
postchlorination, sufficient CT must be provided in the
combined flocculation basins, sedimentation basins, and
reservoirs. Since the flocculation basins and sedimenta-
tion basins operate under different conditions than the
reservoirs, different required CT values were considered
in assessing if sufficient CT was provided with both pre-
and postchlorination. The required CT values were ob-
tained from a U.S. EPA guidance manual (3). The floc-
culation basin and sedimentation basins had a required
CT of 121 based on a chlorine residual of 1.0 mg/L, pH
7.5, and a temperature of 0.5°C while the clearwell had a
required CT of 119 based on a chlorine residual of 0.4
mg/L, pH 7.5, and a temperature of 0.5°C. Actual CT
values were calculated at the peak average daily flow
and compared to the required CT. The capacity on the
performance potential graph (Figure 2) is the flow where
the sum of the ratio of the actual CT to the required CT
for the two different sections equals 1.0. In determining
the actual effective disinfectant contact time, 50 percent
of the total flocculation and sedimentation volume and
10 percent of the nominal volume in the reservoir were
assumed available for contact.
When only using postchlorination for disinfection, the
plant will have to provide a CT of 119 to obtain the 1.5
logs of cyst inactivation in the reservoirs. This CT is
based on a chlorine residual of 0.4 mg/L, pH 7.5, and a
temperature of 0.5°C. The effective disinfectant contact
time was calculated assuming 10 percent of the nominal
volume in the reservoir available for contact.
Based on these criteria, the disinfection system of the
plant was rated at a capacity of 3.3 mgd when both
prechlorination and postchlorination were considered.
When only postchlorination was considered, the disinfec-
tion capacity of the plant was reduced to 2.2 mgd.
It is important to note that the actual levels of disinfection
required for Plant No. 19 in the future and any limitations
on prechlorination will be determined by the state. The
estimates in this CPE of the required number of log
reductions of Giardia cysts and viruses, the allowances
for actual contact times in the floc/sed basin and reser-
voirs, and restrictions on prechlorination may change
when the state develops its final disinfection and disinfec-
tion byproduct regulations.
As shown in the performance potential graph (Figure 2),
each major unit process for Plant No. 19 has a rated
capacity that exceeds the peak average daily operating
flow. This assessment assumes that the existing struc-
tures have adequate structural integrity and adequate
hydraulic capacity to operate at the higher flow rates.
While the performance potential graph shows that Plant
No. 19 can adequately treat 2.0 mgd, the CPE did not as-
sess whether or not the two pump stations can actually
supply that amount of water to the plant or if the plant can
hydraulically handle this flow.
PERFORMANCE ASSESSMENT
A part of the CPE includes an assessment of the past
and present performance of Plant No. 19. This perfor-
mance assessment is intended to identify if specific unit
treatment processes are performing as expected and if
the plant will be able to comply with current and future
regulations. The performance assessment is based on
data from plant records and data collected during special
studies performed during the CPE.
Figure 3 shows the raw water turbidity measured by the
plant staff over the previous 12-month period. The tur-
bidity of the raw water was relatively stable, indicating
that with proper process control the plant should be able
to achieve a stable finished water quality. Figure 4 shows
a probability plot of this data showing that 95 percent of
the time the raw water has a turbidity of less than 8.0
NTU. This relatively stable, low turbidity raw water
provides a comparatively high quality source of water for
Plant No. 19.
The finished water turbidity measured by the plant staff
over the previous 12-month period is shown in Figure 5,
along with the present and future turbidity requirements.
Figure 6 presents a probability plot of this data and
shows that the plant is producing a finished water tur-
bidity of 0.5 NTU less than 10 percent of the time. Both
Figures 5 and 6 indicate that, while the plant is meeting
the present requirements, it would be in almost con-
tinuous noncompliance with future regulations.
As part of the CPE a continuous on-line turbidimeter was
installed on the effluent of filter "C". Data was collected
over the 2 days of the CPE. Figure 7 shows the filtered
water turbidity measured from filter "C" for a 14-hour
period during the CPE. For most of this time period, the
turbidities were above 1.0 NTU, the present turbidity re-
quirement. This filter never produced water less than the
0.5 NTU required by the future regulations. During this 14
hours, there were also several rapid changes in turbidity
from the filter. During these rapid changes, the possibility
exists for the filter to pass large numbers of cysts into the
finished water. A properly operating filter should be able
to produce a stable turbidity of 0.1 NTU.
The turbidimeter also measured the turbidity from filter
"C" immediately after it was backwashed. This is an
especially critical time for filter performance and provides
an indication of the adequacy of the operation of the fil-
ters and preceding unit processes. With adequate
facilities and operation of preceding unit processes, a
properly operated filter should produce a finished water
turbidity of approximately 0.1 NTU and only experience a
0.2 NTU rise in turbidity in the finished water for ap-
E-8
-------
Figure 3. Raw water turbidity vs time.
Q
6 June 1990
lfc> £*>
&
JUN JUL RUG SEP OCT NOV DEC JRN90 FEB MHR RPR MRY JUN JUL
Days
Figure 4. Percentile plot of raw water turbidity.
ts
5 June 1990
> t> t>
10 50 90
Percent of Time Values
-------
proximately 10 minutes after being restarted following
backwashing. As shown in Figure 8, the turbidity from fil-
ter "C" increased to almost 2.5 NTU after backwashing,
but within 20 minutes was producing a finished water of
less than 0.1 NTU.
In summary, Plant No. 19 appears to be meeting its
present turbidity requirement, but performance of an in-
dividual filter exceeded these requirements. Results from
continuous monitoring of the filtered water from an in-
dividual filter also indicated variable turbidity removal
capability which can contribute to the passage of cysts
into the finished water. Performance of the filter immedi-
ately after backwash was poor, but it produced excellent
finished water quality after approximately 20 minutes.
Given the current operation, the plant could not meet the
future turbidity regulations.
PERFORMANCE LIMITING FACTORS
Performance limiting factors in the areas of design,
operation, maintenance, and administration were iden-
tified based on the information obtained from the plant
tour, interviews, performance and design assessments,
and special studies. Each of the factors were classified
as A, B, or C according to the following guidelines:
A Major effect on a long-term repetitive basis.
B Minimal effect on a routine, or major effect on a peri-
odic basis.
C Minor effect.
The A and B factors identified were prioritized as to their
relative impact on performance and are summarized
below:
1. Plant Administrator's Policies - Administration (A)
Policies and procedures established by the plant ad-
ministrators have interfered with operation of the
plant and are a major factor limiting performance.
Policies such as requiring the backwashing of two fil-
ters together to reduce energy costs, and budget pro-
cedures that tend to fund low-cost, low-priority items
rather than critical higher priority items, directly im-
pact plant performance. In addition, the water
department's personnel resources are not properly
managed, allowing limited coordination between the
two departments that has resulted in operations staff
personnel performing tasks unrelated to optimizing
plant performance (e.g., grass cutting). Finally, the
administrators do not understand their responsibility
to provide for a self-sustaining utility as demonstrated
by their lack of financial support for any future facility
or modifications to the existing facility.
Figure 5. Finished water turbidity vs time.
I ¦»¦' I' ¦ ¦ 11 " i' I n i ¦ 111111
CD
6 June 1990
«>~> >
>
»¦ > > M>»-
~B> >
LO
>N
+>
TJ
.O
(.
3
•t>E> ~ E>* »• (MMMSMMK&O
WH
[» t> C>MS>
>
> >
> 6>
ts
I" 111
Mill
I " " I
JUN JUL RUG SEP OCT NOV DEC JRN90 FEB MflR RPR MRY JUN JL
Days
Present
Requ i rement
Future
Requ i rement
E-10
-------
Figure 6. Probability plot of finished water turbidity.
G June 1990
ntte££«>OE>o >
WIM| I I I
10 50 90
Percent of Time Values <
99.9
Figure 7. Filter "C" turbidity during CPE.
E-11
-------
Filter "C" turbidity after backwash.
Figure 8.
in
cvj
June 1990
oj - -
D
I-
Z
in
>s
¦p
Present
Requ 1 remerit
Future
Requ f rement
in
0
5
10
15
20
25
Time (minutes)
2. Plant Administrator's Planning - Administration (A)
The plant administrators have focused on planning
for a new water treatment plant in the future while
delaying support for the existing plant. For instance,
repairs to the existing plant are only approved in
crisis situations. None of this planning has included
provisions for adequate financial support of either the
existing or proposed new plant. This approach has
stifled aggressive efforts to optimize existing plant
capability and led to the acceptance of a deteriorating
plant even with no firm commitment to a new facility.
3. Process Control Testing Operation (A)
Process control testing is essential for water plants
served by surface sources because of the possibility
of rapid changes in raw water quality. While the raw
water that Plant No. 19 treats is relatively stable and
some jar testing is practiced, the process control test-
ing program to optimize unit process performance is
marginal. Turbidity measurements of the floccula-
tion/sedimentation basin effluent needed for control-
ling chemical doses and optimizing performance are
not regularly performed and recorded. Individual filter
effluent turbidities were also not measured.
4. Process Flexibility Design (A)
Additional flexibility is needed in the plant to permit
addition of filter aids, polymers, and taste and odor
control chemicals. The capability to feed stabilization
chemicals at different points in the plant is also
needed.
5. Ultimate Sludge Disposal - Design (A *)
The city has been issued a discharge permit from the
state with limits that will likely require the installation
of treatment and disposal facilities for the plant's
sludge and backwash water by the fall of 1990. As of
the date of the CPE, no action has been taken by the
city to meet the permit requirements. This factor is
given an A* because the potential exists that actions
taken by the state resulting (rom violations of this per-
mit could ultimately affect the performance of the
plant. For instance, limits on the discharge of sludge
from the sedimentation basin could limit its perfor-
mance, or limitations on the quality of backwash
water discharged could limit the ability of the plant to
adequately clean the filters.
6. Plant Coverage Administration (B)
It is essential that personnel be at the plant at all
times while the plant is in operation to make process
adjustments and make sure all equipment is properly
operating. The practice of operating the plant unat-
tended overnight is unacceptable. Operation of the
plant at a higher flow rate for shorter time periods
may alleviate the need for third-shift coverage.
E-12
-------
7. Application of Concepts and Testing to Process
Control - Operation (B)
While the plant staff are certified and have a
knowledge of water treatment, they are not presently
applying their knowledge to optimizing performance.
Poor filter flow control practices were causing fluc-
tuating effluent turbidities. Other poor filter operation
practices included backwashing two fitters at the
same time at an inadequate flow rate and putting the
entire plant flow through one filter. Lime and alum
were also fed at the same point
8. Process Controllability - (B)
The filter rate of flow control valves are not function-
ing properly to allow consistent flow to the filters.
This allows flow rate fluctuations and deteriorates
performance.
9. Lack of Standby Units for Key Equipment (B)
The plant has only one alum and lime feeder and
backwash pump. These are key pieces of equipment
that would seriously impact performance if they
failed.
10. Finished Water Storage/Distribution (B)
The use of uncovered finished water reservoirs repre-
sents a potential for significant impact on water
quality because of uncontrolled access by wildlife, in-
sects, and debris.
The inoperative mechanical flocculator was considered to
possibly have a minor impact on performance and may
need to be repaired to enhance plant capabilities.
Though beyond the scope of this evaluation, the current
practices of handling and storage of chlorine in the plant
are not considered safe.
PROJECTED IMPACT OF A CCP
A Composite Correction Program (CCP) is a formal and
comprehensive program that systematically addresses
the factors identified as limiting the plant's performance
during the CPE A CCP is typically implemented without
major capital improvements and is implemented by local
personnel under the guidance of a facilitator external to
the plant staff. The facilitator can be a consultant or other
qualified person.
Plant No. 19 would benefit from a CCP since it is
projected that the plant could be operated to meet the re-
quirements of the new regulations without major capital
expenditures. All of the factors identified to limit the
plant's performance, however, would have to be cor-
rected. Before a successful CCP could be implemented,
the plant's administrators would have to make major
changes in their level of support for the existing plant.
This would require changes in funding policies and real-
location of city staff for adequate plant coverage.
REFERENCES
1. U.S. EPA. 1984. Handbook - Improving POTW Per-
formance Using the Composite Correction Program
Approach. EPA 625/6-84-008. Cincinnati, OH: U.S.
EPA.
2. Renner, R.C., B.A. Hegg, and D.F. Fraser. 1989.
Demonstration of the Comprehensive Performance
Evaluation Technique to Assess Montana Surface
Water Treatment Plants. Phoenix, AZ: Association of
State Drinking Water Administrators Conference.
3. U.S. EPA. 1989. Guidance Manual for Compliance
with the Filtration and Disinfection Requirements for
Public Water Systems Using Surface Water Sources.
Washington, D.C: U.S. EPA, Office of Drinking
Water.
E-13
-------
Intentionally Blank Page
-------
APPENDIX F
Sample Special Study
-------
Intentionally Blank Page
-------
April 4, 1989
SAMPLE SPECIAL STUDY
(Prior to Implementation)
TITLE: Reduce Plant Flow
HYPOTHESIS: A reduction in peak instantaneous operating flow will decrease finished
water turbidity.
APPROACH:
1. Reduce peak instantaneous operating flow to plant to 1,000 gpm by adjusting valve
at raw water pump.
2. Relocate pressure gauge to location upstream of throttling valve.
3. Reduce chemical feed rate in proportion to flow.
4. Measurements: (1 week prior to change/1 week after change.)
a. Raw water turbidity every 4 hours during operation.
b. Settled water turbidity every 4 hours during operation.
c. Effluent turbidity from each filter every 4 hours during operation.
d. Continuous measurement of finished water turbidity with existing turbidimeter.
e. Influent water temperature on daily basis.
DURATION:
One week under current conditions and 1 week under changed conditions. If raw
water quality changes dramatically during the period, repeat.
EXPECTED RESULTS:
1. Reduction in settled water turbidity and in variations.
2. Reduction in filter water turbidity and in variations.
3 Reduction in finished water turbidity to <0.1 NTU on continuous basis.
4. Increase in filter run time.
5 Reduction in turbidity based on filterability test.
CONCLUSIONS:
To be completed after study.
IMPLEMENTATION:
To be completed after study.
F-1
-------
Intentionally Blank Page
-------
6- -v
APPENDIX G
Sample Water Treatment Plant Operating Procedure
-------
Intentionally Blank Page
-------
STANDARD OPERATING PROCEDURE
Section 1: Equipment Calibration
Subject: Cationic and Nonionic Polymer Feed Pumps
Number: 1.2
Date: 4/11/89
Purpose:
To derive the approach to calibrate the cationic and nonionic polymer feed pumps.
1. Open valve on polymer pump discharge that allows polymer to be pumped to polymer solution tank.
2. Shut off valve to injection point(s).
3. Set"% of Full Stroke" on pump at 20.
4. Turn on pump.
5. Using a 1,000-mL graduated cylinder* and a stopwatch, measure the amount of time it takes to fill the
cylinder to at least the 300-mL mark. To simplify calculations, measure flow to the nearest minute
after passing the 300-mL mark. Repeat this measurement and record both values.
6. Repeat Step 5 for"% of Full Stroke" settings of 40, 60, 80, and 100.
7. Calculate the flow in milliliters per minute by dividing the measured flow by the number of minutes.
Do this for each measured flow.
8. Plot each value of "Flow in mLVmin" versus "% of Full Stroke" setting on an 8-1/2 x 11-in. sheet of
graph paper (10 squares to the inch). Plot flow on the vertical axis, setting on the horizontal axis.
A straight line plot should result; some fitting of a "best fit" line between points may be necessary.
(NOTE: Settings below 20 and above 80 should be avoided unless the flow from the feeder is
measured at that particular setting.)
'Before taking any readings, rinse the cylinder with the polymer and dump out the excess.
G-1
-------
240
220
200
180
160
140
120
100
80
60
40
20
0
CATIONIC POLYMER CALIBRATION CURVE
I
I
\
\
!
/
/
/
i
z''
/¦
...... I ........
s''
X
y''
—
y
/
—
:
/
y'
I
X
1
I
0 20 50 80 100
PUMP SETTING (% FULL SCALE)
-------
APPENDIX H
Daily and Monthly Control Sheets for a Small Direct Filtration Plant
-------
Intentionally Blank Page
-------
WATER TREATMENT PLANT — DAILY DATA SHEET
Plant Operator Day Date
DAILY INFORMATION
Taraet Plant Flow
aDm
Cationic Volume
aal
Plant Totalizer
Nonionic Volume
aal
Influent Volume
aal
Alum Added
lb
Backwater Totalizer
aal
Headtoss Settina
in.
Backwash Volume
aal
No. Backwashes
#
Finished Volume
aal
Chlorine Addition
Hour Meter Rda.
Scale Readina
ODeratina Time
hr
Mass Used
lb
Est. Recycle Volume
aal
TIME-RELATED INFORMATION:
Time of Reading
Plant Influent
Turbidity (NTU)
pH (units)
Taste & Odor (#)
Alkalinity (mg/L)
Plant Effluent
Turbidity (NTU)
pH (units
CI2 Residual (mg/L)
Filter Performance
Influent Turb (NTU)
No.1 Eff.Turb. (NTU)
No.2 Eff.Turb. (NTU)
No.3 Eff.Turb. (NTU)
No.4 Eff.Turb. (NTU)
Backwash Recycle
Turbidity (NTU)
Estimated Flow (gpm)
Est.Pump On-Time (min)
Chemical Addition
Filterability (NTU)
Alum
Target Dose (mg/L)
Feed Setting (%)
Mass Flow (lb/day)
Cationic Polymer
Target Dose (mg/L)
% Solution (%wt)
Pump Setting (%)
Pump Rate (mLVmin)
Anionic Polymer
Target Dose (mg/L)
% Solution (%wt)
Pump Setting (%)
Pump Rate (mLVmin)
Carbon
Target Dose (mg/L)
Feed Setting (%)
H-1
-------
EXAMPLE MONTHLY PROCESS CONTROL DATA SHEET
MONTH;
YEAR:
DAY
PLANT
FLOW
(jtpm)
OPERATING
TIME
(hrs)
INFLUENT
VOLUME
(UPd)
BACKWASH
VOLUME
(Spd j
FINISHED
VOLUME
(gal)
!"
backwash j recycle
1 VOLUME
TURBIDITY (NTU)
INFLUENT
FILTER 1
I
MIN
.l-ILUENT
(7>)
M1N
MAX
AVG
MIN MAX
AVG
MAX ) AVG
1
i
!
3
¦ "
:
4
5
j
6
7
3
;
9
--
- - ---
i
10
n
12
•
.21
¦
1
' i
'!
j
!
i
1
i
—
16
...LI
18
. |
• •
^
;
1 '
IV
¦
!
20
1
i
• ¦
!
i
i
22
!
!
1
23
24
....
-
!
•
2?
I ;
2*
2?
_ •
1
*
i : 1
t « i
i
J j i
2?
; i :
29
—
¦ — -
.
;
-Ji
— i J
MIN
' "¦ "
—
i
|
MAX
avg
r
1 ;
-------
EXAMPLE MONTHLY PROCESS CONTROL DATA SHEET
MONTH: YEAR:
pH
TEMP
TASTE A ODOR
ALKALINITY
CHLORINE FEED
ALUM FEED
CATiONIC POLYMER
ANIONIC POLYMER
DAY
INF
EFF
INF
INF
EFF
INF
EFF
SETTING
USED
DOSE
SETTING
DOSF.
SETTING
DOSE
SOI/N
SETTING
DOSE
SOl.'N
(units)
(units)
(deg F)
(0-5)
(0.5)
(rcp/L)
(nrijt/1 )
(lb/d)
(lb)
(mgr'1.)
(%)
( mg/L)
(%)
(m*/L)
(%)
(.¦nfi/L)
1
2
I
J
j
'
4
1
5
7
ft
1
9
r '
ID
i
!
!
U
12
i
i
13
1 i
i
14
I !
1 !-
i i
1
....
1
i K»
i i
1 I
I
17
1 I
! . i
IS
!
;
t i j
19
i
t
I i
20
i
i
21
I
| |
i j
i
i
j
1 23
¦
1
1
| 24
i
;
!
!
! ;
i
j
• I i i
•
j 26
! ¦
i
1 1 1 1
1 ?7
I
i
[
!
i
I
<
29
'
1
i
?0
1
i
1
i
i i !
-M
i
i
.MIN
1
i
"
1 t
MAX
- 1
j
A V C>
i i !
i
-------
Intentionally Blank Page
-------
APPENDIX I
Sample Jar Test Procedure
-------
Intentionally Blank Page
-------
SAMPLE WATER TREATMENT PLANT
STANDARD OPERATING PROCEDURE
The following represents an example jar test procedure. There are numerous techniques that can be used
to run jar tests and many are site specific. Therefore, to best correlate jar test results to individual plant
performance, site-specific jar test procedures should be developed.
Section 3: Process Control
Number:
Subject: Jar Test
Date:
1. Run on plant influent.
A. Run on weekly basis during routine operation.
B. Run on an "as needed" basis during periods of changing raw water quality.
2. Prepare stock solutions of chemicals to be tested.
A. Alum stock solution (using dry alum).
i) Determine the dilution of the stock solution. The percent dilution selected should be based on:
(1) the amount of chemical required to treat the water and (2) achieving an easily applied dose
(e.g., 1 ml_ stock solution equals 1 mg/L dose). For example, if 2 liter jars are used and it is
desired to test dosages between 20 mg/L and 70 mg/L at 10 mg/L increments, a 2 % stock
solution could be prepared. This would allow a 2 mL dose to equal 20 mg/L, a 3 mL dose to
equal 30 mg/L, etc. The following table can be used to determine the desired dilution when
using 1 or 2-L test jars.
mg/L DOSAGE PER mL OF
SOLUTION CONCENTRATION STOCK SOLUTION ADDED:
(%) (mg/L) To 2-L jar To 1 -L jar
0.1 1,000 0.5 1
0.2 2,000 1.0 2
0.5 5,000 2.5 5
1.0 10,000 5.0 10
1.5 15,000 7.5 15
2.0 20,000 10.0 20
ii) Prepare the stock solution as follows: add the appropriate amount of alum required to make the
stock solution. For example, the amount of alum that must be added to a 1-L volumetric
flask to obtain various solutions is presented below.
SOLUTION CONCENTRATION mg OF ALUM ADDED
(%) (mg/L) TO 1-L Flask
0.1 1,000 1,000
0.2 2,000 2,000
0.5 5,000 5,000
1.0 10,000 10,000
1.5 15,000 15,000
2.0 20,000 20,000
1-1
-------
iii) Add the appropriate amount of dry alum and fill the container to the 1 -liter mark with the distilled,
demineralized or tap water.
iv) For other volumes of stock solutions, the following formula can be utilized:
nms aii ,m = (% solution) x mL solution
100
where: % solution = desired weight percent stock solution.
mL solution = desired volume of stock solution.
For example, the grams of dry alum required to make up 1 liter (1,000 mL) of 1 % stock
solution can be calculated as follows:
gms alum = (1°/°) x 1.000
100
= 10 gms or 10,000 mg
B. Liquid alum or liquid polymer stock solution.
i) Determine dilution of stock solution (see first table above).
ii) Assume a 1 liter (1,000 mL) polymer stock solution is to be prepared.
Polymer density = 8.84 lb/gal
The amount of concentrated polymer that must be added to prepare any dilution may be
calculated by using the following formula:
mL chemical = (% solution) x (mL solution) x (8.34 lb/gal)
100 x (density of chemical, lb/gal)
where: mL chemical = amount of liquid alum or polymer that must be added to prepare the desii
stock solution.
% solution = desired weight percent stock solution.
mL solution = desired volume of stock solution.
8.34 lb/gal = weight of water.
density of chemical = density of alum or polymer being used (obtain from supplier/manufactu
In the above example:
mL chemical = (0-1%) x 1,000 mLx 8.34 lb/gal
100 x 8.84 lb/gal
= 0.94 mL
NOTE: When preparing stock solutions, the water used to dilute the chemical should be the same
as in plant conditions. For example, if dry alum or polymer products are diluted with plant treated
water prior to application, plant treated water should be used to prepare stock solutions. If products
are fed neat (i.e., undiluted), stock solutions should be prepared with distilled or demineralized
water. Excessive chlorine residuals in tap water may break down some polymer products.
I-2
-------
iii. Set up jar test apparatus and arrange glassware.
iv. Fill all jars to the 2-liter mark with plant raw water.
v. Measure the appropriate amount of chemicals into syringes and place syringes next to jars. Film
cannisters can also be used to hold measured chemicals. Place only one type of chemical into each film
cannister or syringe.
vi. Rapid Mix.
A. Turn mixer to maximum speed.
B. Dose alum and cationic polymer coagulant in all jars simultaneously and stir 30 seconds. Place
chemicals as close to the impeller tip as possible.
C. After 30 seconds of mixing, reduce mixer speed to 35 rpm.
vii. Flocculation.
A. Maintain mixer speed at 35 rpm and mix for 20 minutes.
B. Observe formation of floe particles in each jar.
C. NOTE: Set mixer speeds and mix times to approximate actual plant conditions.
viii. Settling.
A. Turn off the mixer and let jars set 20 minutes (set to actual plant condition).
B. Take samples of 30 to 40 mLfrom the sample tap located 10 cm from the top of jar.
C. Sample all jars "simultaneously" and place sample into small beakers.
D. Measure the turbidity of each sample.
ix. Recording Results.
A. Record test results on the attached lab sheet.
B. Jar with lowest turbidity indicates best coagulant dose.
I-3
-------
Jar Test Report
TEST NO. WATER SOURCE TURB PH
DATE TIME COLLECTED ALK TEMP
JAR TEST DATA
JAR NUMBER
1
2
3
U
5
6
RAPIO MIX
RPM
DURATION
FLOCCULATION
RPM
DURATION
COAGULANT
MG/L
CAT POLYMER
MG/L
FILTER AID
KG/L
JAR TEST RESULTS
JAR NUMBER
1
2
3
U
5
6
TIME OF
DEPTH OF SETTLING
TURB
%
TURB
%
TURB
X
TURB
%
TURB
X
TURB
X
SETTLING
SAMPLE VELOCITY
(NTU)
REM
(NTU)
REM
(NTU)
REM
(NTU)
REM
(NTU)
REM
(NTU)
REM
(MIN)
(CM) (CM/MIN)
1
3
5
10
15
20
pH
JAR NUMBER 1
TURB
(NTU)
FILTERED TURBIDITY
COMMENTS:
TURB
(NTU)
TURB
(NTU)
TURB
(NTU)
TURB
(NTU)
TURB
(NTU)
1-4
-------
J
APPENDIX J
Design-Related Performance-Limiting Factors Identified in Actual CPEs
-------
Intentionally Blank Page
-------
DESIGN-RELATED PERFORMANCE LIMITING FACTORS
The design problems listed in this appendix were identified during actual CPEs and CCPs. Each of the
identified problems was felt to be directly or indirectly impacting plant performance. These problems are
discussed in the context of the following categories:
Intake Structures/Raw Water Pumps
• Arrangement of screens allows excessive accumulation of river moss.
• Intake structure configuration allows accumulation of silt and mud.
• Intake orientation and screen location allows buildup of slush ice during winter.
• Infiltration gallery fails because of accumulation of silt.
• Constant speed, high volume pumps make plant flow control difficult.
Rapid Mix/Flocculation
• Rapid mix facilities are not provided to incorporate chemicals into plant flow.
• Back mix reactor mixing system requires additional coagulant chemical feed.
• Mixing energy is inadequate to provide instantaneous chemical mix.
• No flocculation facilities are provided.
• Flocculation is conducted at bottom of sedimentation basin, resulting in excessive turbulence for good
settling.
• Single-stage flocculation with limited detention time limits floe formation.
• Large volume flocculation is provided with only one stage.
• Constant speed flocculation drives allow no energy adjustment.
• Lack of baffling between adjacent flocculation and sedimentation basins results in excessive turbulence
that degrades sedimentation performance.
Sedimentation
• Freezing during cold weather.
• Short-circuiting due to poor inlet baffle configuration.
¦ Unbalanced weirs cause uneven draw-off from basin.
• Leaking weirs cause basin short-circuiting.
• Excessive surface overflow rates make solids capture difficult.
• Location of flocculation and sedimentation basins in series (e.g., floc/sed - floc/sed) limits performance of
both unit processes.
• Shallow depth limits sludge storage area and promotes solids carryover.
Intake Structures
Raw Water Pumps
Rapid Mix
Flocculation
Sedimentation
Filtration
Disinfection
Sludge/Backwash Water Handling
Laboratory Facilities
Miscellaneous
J-1
-------
Filtration
• Improper rate control valve causes rapid fluctuation in filter flow rate.
• Malfunctioning rate control valves cause fluctuation in filter flow rates.
• Underdrain failure disrupts media.
• Location of air backwash header beneath support gravel results in "blown" support gravels when air
diffuser fails.
• Failure of filter cell dividers in an automatic backwash (travelling bridge) filter results in poor filter bed
development and backwash.
• Inadequate control of backwash in an enclosed self-backwashing filter causes a severe buildup of sludge
within the filter.
• Lack of surface wash facilities results in severe accumulation of mudballs.
• Automatic backwash control limits flexibility to extend backwash time or increase volume, resulting in an
accumulation of dirt and mudballs in the filter.
• Limited water depth above filter media causes severe air binding in filters.
• Raw water quality too high in turbidity for direct filtration.
Disinfection
• Lack of detention time in clearwell limits contact time available to meet CT requirements.
• Lack of baffling in clearwell limits contact time available to meet CT requirements.
• Uncovered treated water reservoir exposes water to contamination.
• Lack of standby chlorinator creates risk of disinfection failure.
Sludge/Backwash Water Treatment
• Return of backwash water to outlet of presedimentation basin increases turbidity load to plant.
• Return of backwash water to head of plant increases risk for passage of cysts through plant.
• Discharge of backwash water to receiving stream without permit potentially limits filter backwash
capability.
• Limited capacity of backwash storage and recycle system places a ceiling on backwash frequency.
• Discharge of sedimentation basin sludge to receiving stream without permit potentially limits ability to
remove sludge from basin.
• Limited capacity of sludge storage lagoons potentially limits capability of sedimentation unit process.
Laboratory Facilities
• Not provided.
• Inadequately equipped.
• Poorly lit and unheated.
• Insufficient floor and bench space.
Chemical Feed Facilities
• No facilities available to feed flocculant or filter aid chemicals.
• Feeders oversized to provide accurate feed rate at low flows.
• No flexibility to feed chemicals at points other than rapid mix.
J-2
-------
• No flexibility to feed stabilization chemicals (e.g., lime, soda ash, etc.) at a location (e.g., after filters)
away from the alum feed.
• Poor measuring and mixing equipment available to make polymer dilutions.
• Long chain polymers being fed at rapid mix, resulting in shearing of chains and ineffectiveness of product.
Miscellaneous
• No flow splitting capability to parallel units.
• Individual process trains require operation of two treatment plants rather than just one.
• Flow measurement inaccurate because of upstream turbulence.
• Lack of flow recording equipment.
• Finished water flow measurement inaccurate because all water flow is not directed through meter.
¦ No sample taps on filter effluents.
• No sample taps on sludge lines or raw water line.
• Automatic operation of plant resulting in numerous startups daily of dirty filters.
• No standby equipment for critical pieces of equipment such as backwash pumps, chlorinators, coagulant
feeders, etc.
• No alarm system for raw or treated water turbidity at plants that are not staffed at all times plant is in
operation.
• No continuous recording turbidimeters on individual filter effluents.
J-3
-------
Intentionally Blank Page
-------
APPENDIX K
Chemical Feed Calculations
-------
Intentionally Blank Page
-------
CHEMICAL FEED CALCULATIONS
Chemicals such as coagulants, flocculants, and filter aids must be used in water treatment to effectively remove col-
loidal particles from the water. To use these chemicals properly, it is necessary to understand the calculations neces-
sary to prepare stock solutions to be used in jar testing and to determine the appropriate feed rates in the plant. These
calculations for alum and polymers are explained in the following paragraphs.
ALUM
Alum Stock Solutions
When conducting a jar test to determine the optimum alum dosage, it is necessary to add varying amounts of alum to
the jars. Since the bulk liquid alum is very concentrated, it is necessary to prepare a diluted stock solution. To simplify
the addition of alum, it is best if the stock solution contains a concentration of alum so that an even volume of stock
solution added to the test jar will result in the desired alum dosage. For example, if the stock solution is made up of a
concentration of 5 grrVL (5 mg/mL), adding 1 mL of stock solution will add 5 mg of alum to the jar. If the test jar con-
tains 1 liler, the resulting dosage will be 5 mg/L. Likewise, adding 2 mL to a Miter test jar will provide a dosage of 10
mg/L, etc. The procedures for making stock solutions from dry and liquid alum are presented below.
Stock Solution from Liquid Alum
An alum stock solution may be prepared using liquid alum by following the procedure below.
1. Determine the concentration of alum by weighing samples or by reviewing the truck driver's load slip.
a. Determine the specific gravity of alum by weighing as follows:
Weigh three 10-mL samples of alum on an analytical balance and calculate the average specific gravity.
For example, assume the average weight of the 10 mL samples is 13.303 gm. The specific gravity is then 1.3303
gm/mL.
b. Determine the concentration by reviewing the load slip. For example, the information reveals the liquid alum being
delivered is 48.18 percent dry alum.
Using Table 1, the specific gravity is then 1.3303 gm/mL.
2. Determine the equivalent amount of alum in the solution and the pounds of dry alum per gallon using Table 1.
For example:
• @ specific gravity (sp gr) of 1.3303
• The percent of dry alum = 48.18%
• The lbs of dry alum per gallon = 5.34 lb/gal
3. Determine the dilution of the stock solution. The following table can be used to determine the desired dilution,
either as a percent by weight solution or a weight per unit volume solution.
CONCENTRATION
SOLUTION (%) (mg/L)
mg/L DOSAGE PER mL OF STOCK
SOLUTION ADDED:
To 1 liter jar To 2 liter jar
0.1
0.2
0.5
1.0
1.5
2.0
1,000
2,000
5,000
10,000
15,000
20,000
2
5
10
15
20
0.5
1.0
2.5
5.0
7.5
10.0
K-1
-------
TABLE 1 .* Densities and Weight Equivalents of Commercial
LB. DRY ALUM
gm DRY ALUM
SPECIFIC
EQUIV. % DRY
PER GAL.
PER L
GRAVITY
LB/GAL
% AI2O3
ALUM"
SOLUTION
SOLUTION
1.0069
8.40
0.19
1.12
.09
11,277
1.0140
8.46
0.39
2.29
.19
23.221
1.0211
8.52
0.59
3.47
.30
35.432
1.0284
8.58
0.80
4.71
.40
48.438
1.0357
8.64
1.01
5.94
.51
61.521
1.0432
8.70
1.22
7.18
.62
74.902
1.0507
8.76
1.43
8.41
.74
88.364
1.0584
8.83
1.64
9.65
.85
102.136
1.0662
8.89
1.85
10.88
.97
116.003
1.0741
8.96
2.07
12.18
1.09
130.825
1.0821
9.02
2.28
13.41
1.21
145.110
1.0902
9.09
2.50
14.71
1.34
160.368
1.0985
9.16
2.72
16.00
1.47
175.760
1.1069
9.23
2.93
17.24
1.59
190.830
1.1154
9.30
3.15
18.53
1.72
206.684
1.1240
9.37
3.38
19.88
1.86
223.451
1.1328
9.45
3.60
21.18
2.00
239.927
1.1417
9.52
3.82
22.47
2.14
256.540
1.1508
9.60
4.04
23.76
2.28
273.430
1.1600
9.67
4.27
25.12
2.43
291.392
1.1694
9.57
4.50
26.47
2.58
309.540
1.1789
9.83
4.73
27.82
2.74
327.970
1.1885
9.91
4.96
29.18
2.89
346.804
1.1983
9.99
5.19
30.53
3.05
365.841
1.2083
10.08
5.43
31.94
3.22
385.931
1.2185
10.16
5.67
33.35
3.39
406.370
1.2288
10.25
5.91
34.76
3.56
427.131
1.2393
10.34
6.16
36.24
3.74
449.122
1.2500
10.43
6.42
37.76
3.93
472.000
1.2609
10.52
6.67
39.24
4.12
494.777
1.2719
10.61
6.91
40.65
4.31
517.027
1.2832
10.70
7.16
42.12
4.51
540.484
1.2946
10.80
7.40
43.53
4.71
563.539
1.3063
10.89
7.66
45.06
4.91
583.619
1.3182
10.99
7.92
46.59
5.12
614.149
1.3303
11.09
8.19
48.18
5.34
640.938
1.3426
11.20
8.46
49.76
5.57
668.078
1.3551
11.30
8.74
51.41
5.81
696.657
1.3679
11.41
9.01
53.00
6.05
724.987
*From Allied Chemical Company "Alum Handbook," modified by adding column, "gm Dry Alum per L."
** (17% AI2O3 in Dry Alum + .03% Free AI2O3.
K-2
-------
4. Prepare the stock solution by a percent solution method, which is a generally accepted method or by a volumetric
solution method.
a. Percent Solution Method.
Assume a 0.1% (1,000 mg/L) solution is desired, or every ml. of stock solution added to a 1-liter jar equals 1 mg/L.
Sp gr of alum (from above) = 1.3303 gm/mL
Concentration = 5.34 lb/gal
The amount of bulk alum solution that must be added to prepare a 1-liter stock solution may be calculated by
using the relationship below.
mLs chemical = (% solution) x (mL solution) x (8.34 lb/gal)
100 x (concentration of chemical, lb/gal)
where mL chemical = amount of liquid alum that must be added to prepare Ihe desired stock solution.
% solution = desired weight percent stock solution.
mL solution = desired volume of slock solution.
8.34 lb/gal = weight of water,
concentration
of chemical = concentration of alum being used (obtain from supplier/manufacturer).
In the above example:
mL chemical= (0-1%) x 1,000 mL x 8.34 lb/gal
100 x 5.34 lb/gal
= 1.56 mL
b. Volumetric Solution Method.
Assume 1,000 mg/L (0.1%) solution is desired, or every mL of stock solution added to a 1-liter jar equals 1 mg/L.
Sp gr of alum (from above) = 1,3303 gm/mL
Concentration = 640.938 gm/L (from Table 1)
The amount of bulk alum solution that must be added to prepare a 1-liter stock solution may be calculated by
using the relationship below.
Vi xCi = V2XC2
Vi = V2C1
C1
where Vi = Volume of bulk alum solution in mL that must be added to 1,000 mL water to
form alum stock solution.
Ci = Concentration of bulk alum solution in mg/L
V2 = Volume of alum stock solution (1,000 m/L)
C2 = Concentration of alum stock solution required (1,000 mg/L)
Determine Ci by converting concentration of bulk alum to mg/L:
mg/L alum = 640.938 gm/L x 1,000 mg/gm
= 640,938 mg/L
Therefore:
V1 - (1,000 mL x 1,000 mg/L)
640,938
V1 = 1.56 mL
Therefore, the alum stock solution is made up by placing 1.56 mL of alum into a 1,000-mL flask and filling the flask
with water to the 1,000-mL mark.
K-3
-------
NOTE: When preparing stock solution, the water used to dilute the chemical should be the same as in actual
plant conditions. For example, if alum is diluted with plant treated water prior to application, plant treated water
should be used to prepare stock solutions. If alum is fed neat (i.e., undiluted), stock solutions should be prepared
with distilled or demineralized water.
Stock Solution from Dry Alum
An alum stock solution may be prepared using dry aium by following the procedure below.
1. Determine the desired concentration of alum stock solution (see Item 3 above).
2. Add the appropriate amount of alum to a given volume of water to make the desired stock solution. The amounts
of alum that must be added to 1 -liter and 2-liter volumetric flasks to obtain various solutions are presented below.
^/-iii^rviTnjiTij-in nig OF ALUM ADDED:
CONCENTRATION -
% SOLUTION (%) (mg/L) TO 1 LITER JAR TO 2 LITER JAR
0.1 1,000 1,000 2,000
0.2 2,000 2,000 4,000
0.5 5,000 5,000 10,000
1.0 10,000 10,000 20,000
1.5 15,000 15,000 30,000
2.0 20,000 20,000 40,000
3. Add the appropriate amount of dry alum and fill the container to either the 1 - or 2-liter mark with demineralized, dis-
tilled, or tap water (see above note).
4. For other volumes of stock solutions, the following formula can be utilized:
a. gmalum= (% solution) x mL solution
100
where % solution = desired weight percent stock solution.
mL solution = desired volume of stock solution.
For example, the grams of dry alum required to make up 1 liter (1,000 mL) of 1 percent stock solution can be cal-
culated as follows:
gm alum = (1%) x 1,000
100
= 10 gm or 10,000 mg
b. gm alum = (solution concentration) x mL solution x 1 gm
10,000 mg
where Solution concentration = Desired solution concentration in mg/L
mL solution = Desired volume of stock solution
For example, the grams of dry alum required to make up 1 liter (1,000 mL) of 10,000 mg/L stock solution can be
calculated as follows:
1gm
gm alum = 10,000 mg/L x 1 L x —-———
1,000 MG
= 10 gm
K-4
-------
Treatment Plant Alum Dose
The desired alum dose should be determined by jar testing, pilot filters, zeta meter, or other means. Once the dose is
determined, calculations must be done to set the chemical feed pumps or dry chemical feeders.
Liquid Alum Feeders
Typically, the chemical feed pump rate is determined by pumping into or out of a graduated cylinder that has the
gradations marked in milliliters. As a result, the chemical feed rate in mL/min must be calculated. This can be
done as follows.
Assume:
Plant flow = 5 mgd
Alum dose = 10 mg/L
Alum dosage = 5 mgd x 8.34 x 10 mg/L
= 417 lb/day
Convert the dosage in lb/day to mL/min as follows:
Alum dose =417 lb/day x 1 day/1,440 min x gal/5.34 lb x 3,785 mLigal
= 205 mLVmin
For any flow rate, the alum addition may be calculated as follows:
mLVmin= (lb/day alum) (3,785 mL/min)
(alum concentration in lb/gal) (1,440)
Dry Alum Feeders
Determine the alum dose in lb/day required, as shown in the example tor liquid alum.
Alum dose = 5 mgd x 8.34 x 10 mg/L
= 417 lb/day
From the feeder calculation curve, determine what feed setting is required to feed 417 lb/day. Set the feeder at
the appropriate setting.
POLYMER
Polymers can be used as coagulant aids and floccutant or filter aids. The proper application of polymers requires
understanding of the calculations necessary to prepare stock solutions for jar testing, preparing dilute feed solutions,
and determining the appropriate feed rates in the plant. These calculations are explained in the following paragraphs.
Polymer Stock Solutions
When conducting a jar test to determine the optimum polymer dosage, it is necessary to add varying amounts of
polymer to the jars. Since the bulk liquid polymer solutions are very concentrated, preparing a dituted stock solution is
also necessary. To make the addition of polymer easy, it is best if the stock solution contains a concentration of
polymer so that an even volume of stock solution added to the test jar will result in the desired polymer dosage. For ex-
ample, if the stock solution Is made up of 1 concentration of 1 gm/L (1 mg/mL), adding 1 mL of stock solution will add 1
mg of polymer to the jar. If the test jar contains 1 liter, the resulting dosage will be 1 mg/L. Likewise, adding 2 mL to a
1-liter test jar will provide a dosage of 2 mg/L, etc.
A polymer stock solution may be prepared using liquid polymer by following the procedure below.
1. Determine the density of the polymer in lb/gal from the manufacturers' literature.
2. Determine the dilution of the stock solution. The following table can be used to determine the desired dilution.
K-5
-------
SOLUTION (%)
0.1
0.2
0.5
1.0
1.5
2.0
CONCENTRATION
(mg/L)
1,000
2,000
5,000
10,000
15,000
20,000
mg/L DOSAGE PER mL OF STOCK
SOLUTION ADDED:
TO 1 LITER JAR
0.5
1.0
2.5
5.0
7.5
10.0
TO 2 LITER JAR
1
2
5
10
15
20
3. Determine the milliliters of polymer that must be added to a volumetric flask to make the desired dilution using the
following formula:
mL chemical = (% solution) x (mL solution) x (8.34 lb/gal)
100 x (concentration of chemical, lb/gal)
where mL chemical = amount of polymer that must be added to prepare the desired amount of stock solution
= desired weight percent solution
= desired volume of stock solution
= weight of water
mL chemical
%solution
mL solution
8.34 ib/ga!
concentration
of chemical
= concentration of polymer being used in lb/gal (obtain from supplier/manufacturer)
For example, the mL of polymer weighing 8.84 lb/gal required to prepare 1,000 mL (1 liter) of 0.1% stock solution
can be determined by:
mL solution = (0.1%) x 1,000 mL x 8.34
100x8.84 Ib/gal
= 0.94 mL
Polymer Dilution
Polymers can be fed as dry product or as a liquid. If liquid polymers are utilized, it is sometimes necessary to activate
them prior to feeding. Activating consists of mixing a diluted solution of polymer. This allows the long molecular
chains that make up the polymer to "unravel" and thus activate. The manufacturer should be contacted to determine
the appropriate dilution at which a polymer should be fed.
To prepare a dilution, the following procedure can be followed.
Assume 500 gallons of 0.5% by weight polymer is to be prepared.
Polymer density = 12.1 Ib/gal
The amount of concentrated polymer that must be added to prepare any dilution may be calculated by using a
mass basis calculation.
1. Determine the weight of 500 gallons of water.
Weight = 500 gallons x 8.34 Ib/gal
= 4,170 ib
2. Determine weight of polymer required to prepare 0.5% by wt solution.
Polymer weight = (0.5%/100) x 4,170 Ib
= 20.85 Ib
3. Determine the volume of polymer required.
Polymer volume = 20.85 lb x (gal/12.1 Ib)
= 1.72 gallons
K-6
-------
Therefore, the diluted polymer solution is made up by placing 1.72 gallons of polymer into a 500-gallon barrel and
filling the barrel with wafer to the 500-gallon mark.
NOTE: Liquid polymer can also be weighed, and 20.85 lbs of polymer can be diluted with 500 gallons of water.
Treatment Plant Polymer Dose
The desired polymer dose should be determined by jar testing, pilot filters, zeta meter, or other means. Once the dose
is determined, calculations must be done to set the chemical feed pumps. Typically, the chemical feed pump rate is
determined by pumping into or out of a graduated cylinder that has the gradations marked in mL. As a result, the
chemical feed rate in mUmin must be calculated. This can be done as shown in the following calculations:
Diluted Polymer
Assume:
Plant flow = 2.5 mgd
Polymer dose = 1 mg/L
Polymer dilution = 0.5%
Polymer density =9.06 lb/gal
Polymer dosage = 2.5 mgd x 8.34 Ib/mg x 1 mg/L
mg/L
= 20.85 lb/day
Convert the dosage in lb/day to gal/day of polymer solution as follows:
Polymer solution = 20.85 lb/day x gal/8.34 lb x 1/(0.5/100)
= 500 gpd
NOTE: For solutions less than 1 to 2% by weight, the density of water may be used in the calculation.
Convert the dosage in gal/day to mUmin as follows:
Polymer dose = 500 gal/day x 1 day/1,440 min x 3,785 mLVgal
= 1,314 mUmin
For solutions less than 2% the solution feed rate may be calculated as follows:
mUmin = (lb/day polymer)(3,785 mUgal)(100)
(8.34 lb/gal)(1,440 min/day)(dilution %)
Concentrated (Neat) Polymer
If concentrated polymer is fed undiluted the solution feed rate in mUmin may be calculated as follows:
mL/mjn= (lb/day polymer)(3,785 mL'gal)(100)
(polymer density, lb/gal)(l ,440 min/day)
For example, assume:
Plant flow = 2.5 mgd
Polymer dose = 1 mg/L
Polymer density =9.06 lb/gal
Polymer dosage = 2.5 mgd x 8.34 x 1 mg/L
= 20.85 lb/day
mLVmin = 20.85 lb/day x 3785 mLVgal
9.06 lb/gal x 1440 min/day
= 6.05 mL/min
K-7
-------
Intentionally Blank Page
-------
l-i
APPENDIX L
Sample CCP Summary Report
-------
Intentionally Blank Page
-------
SUMMARY REPORT
WATER TREATMENT PLANT NO. 5
COMPOSITE CORRECTION PROGRAM
L-1
-------
TABLE OF CONTENTS
Page No.
List of Figures 2
Introduction 3
CPE Results 3
CCP Significant Events 4
CCP Results 5
Conclusions 7
References 7
LIST OF FIGURES
Page No.
Figure 1. Finished water turbidities for Plant No. 5 6
Figure 2. Raw water turbidities for Plant No. 5 6
L-2
-------
INTRODUCTION
The CCP approach is a proven procedure for improving
performance of wastewater freatment plants (1). This ap-
proach consists of two components: the CPE phase and
the CCP phase. A CPE is a thorough review and analysis
of a plant's design capabilities and associated
administrative, operation, and maintenance practices. It
is conducted to identify factors that may be adversely im-
pacting a plant's capability to achieve optimal perfor-
mance. Its major objective is to determine if significant
improvements in performance can be achieved without
major capital improvements. A CCP is a performance im-
provement phase that may be implemented if results
from the CPE indicate that improved performance can be
achieved. During the CCP phase, factors identified by the
CPE are systematically eliminated. The major benefit of a
CCP is that it optimizes the capability of existing facilities
without the expense of major capital improvements.
The state initiated a program to evaluate and
demonstrate the effectiveness of the CCP approach at
small water treatment facilities using surface water sup-
plies (2). The state hired a consultant to develop and im-
plement the approach. As part of this project, a CPE was
conducted at water treatment Plant No. 5 in August 1988.
The CPE revealed that the plant had some performance
problems and that the top ranked factors identified were
process control related. It was felt that operator training,
conducted as a portion of a CCP, would improve plant
performance. This report summarizes the results of the
CCP, which was initiated in April 1989.
CPE RESULTS
A CPE was conducted August 22-25, 1988, at water
treatment Plant No. 5. The plant is a direct filtration
facility constructed in 1978. Treatment includes coagulant
chemical feed (alum and cationic polymer), flocculation in
a reaction basin, nonionic polymer filter aid feed, filtration
through four dual media filters, postchlorination, and
gravity flow from the plant to storage and distribution.
Raw water is supplied from a multiple-use lake located
18 mites northwest of the plant. Raw water quality is
generally good in winter months, with turbidities in the 5
to 10 NTU range; but prevailing westerly winds often stir
up sediments in the relatively shallow lake in other
seasons, resulting in raw water turbidities as high as 50
to 280 NTU.
A review of operating data for the previous year revealed
that the plant was generally producing water of less than
1.0 NTU, but would not meet the new Surface Water
Treatment Rule (SWTR) (3) requirements of 0.5 NTU 95
percent of the time. Further performance evaluation ef-
forts included a special study to determine the turbidities
before and after backwashing. Results indicated that filter
effluent turbidities increased to over 3.2 NTU and did not
drop below 1.0 NTU for over 2 hours. Optimum perfor-
mance would be a 0.2 NTU increase for less than 10
minutes and return to operating turbidities of less than
0.1.NTU.
A performance potential graph projected that the design-
rated 3.0 mgd facility would have to be derated to 1.5
mgd because of a severe air binding problem identified
with the 3.0 mgd filter loading rates. This problem was
exaggerated by the design of the filter effluent header,
which allowed the formation of negative pressure in the
filter underdrains. A short detention time in the reac-
tor/flocculation basin also resulted in a projected capacity
less than design for this unit process. A longer time was
felt to be necessary because of the longer reaction time
associated with cold water during winter operation.
The plant's performance limiting factors were assessed
and prioritized in order of significance as follows:
1. Operator Application of Concepts and Testing to
Process Control - Operation
The plant had no formal process control program to
provide information from which operational decisions
could be made. Although the operators had a good
understanding of water treatment, they were not ap-
plying their knowledge to operation of the plant. Be-
cause of the highly variable raw water quality, it was
essential that the plant be monitored continuously
and coagulant dosages changed to maintain a con-
sistent high quality finished water.
2. Process Control Testing - Operation
The lack of process control testing resulted in insuffi-
cient data being collected to properly assess plant
performance (e.g., jar testing, followed by filtration
through filter paper, was not being conducted to op-
timize the coagulation process).
3. Filtration - Design
Turbidity measurements taken at the time of the
evaluation and microscopic particulate testing per-
formed by state personnel demonstrated that the fil-
ters were not performing optimally. The presence of
filter media in the clearwell was an indication that the
filters may have been damaged by backwashing or
the release of air from the severely air-bound filters.
More involved evaluations were felt to be necessary
to determine if the support gravels were damaged.
Filter capacity was also being affected by air binding
and periodic high raw water turbidities, necessitating
frequent backwashing. The filters were derated from
3.0 mgd to 1.5 mgd because of the identified
problems.
4. Raw Water Turbidity - Design
The turbidity of the raw water often exceeded that
normally recommended for the direct filtration treat-
ment process. During periods of high turbidity, it was
L-3
-------
projected that it would be necessary to reduce plant
flow rates to produce an acceptable water.
5. Plant Coverage - Administration
The plant was not attended on weekends and the
operators were often conducting other duties away
from the plant during weekdays. It was assessed
that this practice would result in undetected periods
of poor finished water quality.
6. Lack of Standby Units - Design
There were no standby alum and polymer units.
Failure of one of the units would result in poor plant
performance.
7. Reactor/Flocculation Basin - Design
The reactor basin was undersized to provide ade-
quate time for flocculation during cold water condi-
tions in winter months. It was projected that the plant
flow rate would have to be reduced during winter to
ensure adequate flocculation.
8. Plant Inoperability Due to Weather - Design
Drought severely impacted the availability of water
from the lake in 1985. An engineering study had
been completed to assess relocation of the intake to
a deeper part of the lake.
The CPE report recommended that a followup CCP be
conducted because the top ranked factors identified were
process control related and it was felt that operator train-
ing would improve plant performance. Also, since the his-
torical peak day demand was only about 1.5 mgd, it was
concluded that the plant could be operated at a lower
flow rate to address the design-related limitations of the
filters and reactor/flocculation basin.
CCP SIGNIFICANT EVENTS
The CCP was initiated in April 1989. Major activities are
briefly summarized below.
• Consultant/State Initial Site Visit (April 3-6,1989)
• Implemented a process control sampling and test-
ing schedule and developed a daily data sheet to
record results.
• Implemented policies/procedures approach.
— Developed procedures for calibrating chemical
feeders and calculating chemical dosages so
that chemical feed rates could be accurately ap-
plied.
— Developed procedures for calibrating effluent
turbidimeter.
— Developed procedure for process control test-
ing and sampling.
• Initiated a special study to determine the effect of
operating the plant at a reduced flow rate and
operating the fillers without a negative pressure. At
the conclusion of the visit, the plant was operated
at 1,100 gpm rather than at 2,100 gpm and a plug
was removed from the filter effluent header to allow
the negative pressure to be released from the filter.
• Identified special studies to be conducted in the fu-
ture including analysis of dissolved oxygen and
temperature in raw water including transmission
line to determine cause of filter air binding, evalua-
tion of effect of rapid mix on coagulant feed, and
analysis of effect of alum and polymer feed points.
• Developed an action/implementation plan and
made assignments to the operating staff and ad-
ministrators with due dates to ensure activity con-
tinued until the next site visit.
• Chemical feed rates were not changed during the
visit because it was desired to have the plant staff
operate the plant at existing dosages following
feeder calibration to evaluate plant performance
with existing known dosages.
• Evaluation Period (April-July 1989)
• Continued process control testing on the plant as
presented in sampling and testing schedule proce-
dure.
• Operated plant at reduced flow rate (1,100 gpm)
and without negative pressure on filter effluent
header.
• Initiated weekly transmission of data to consultant
and initiated weekly phone calls between plant staff
and consultant.
• Consultant developed computer spreadsheet to
analyze plant data.
• Installed accurate pressure gauges on lake intake
pumps to relate pump discharge pressure to pump
output.
• Sent finished water turbidimeter to factory service
center for repair.
• Plant staff modified daily data sheet based on
operating experience.
• Purchased dissolved oxygen meter for special
study on filter air binding.
• Welded sample taps and chemical feed taps on
plant influent line before and after orifice plate in
preparation for chemical feed special study. The
plant staff hired a local welder to make the welds.
• Consultant/State Site Visit (June 26-27,1989)
• Conducted jar tests using filter paper and estab-
lished new chemical feed rates for the alum and
cationic polymer. Plant performance improved
dramatically prior to the end of the site visit.
• Developed a procedure for jar testing using filter
paper to correlate results with plant performance,
-------
Explained the conduct and interpretation of the jar
test/filter paper procedure to the operating staff.
• Expanded process control program to include jar
testing/filter paper testing to establish chemical
feed rates.
• Reviewed chemical feed calculations with plant
staff.
• Investigated filter backwash and determined that
additional wash time would be required to ade-
quately clean the filters.
• Updated the special study on relocation of alum
and cationic feed points.
• Updated the action-implementation plan.
• Evaluation Period (July-October 1989)
• Implemented full plant process control program
including evaluating raw water quality and deter-
mining the correct coagulant and filter aid feed
rates. The jar test was utilized to indicate required
chemical doses when plant raw water quality
changed.
• Continued weekly transmission of data to consult-
ant and weekly phone calls between plant staff and
consultant.
• Consultant developed monthly data sheet to
analyze plant data.
• Relocated the feed points for alum and cationic
polymer addition to take advantage of a hydraulic
flash mix at the orifice plate located in the influent
piping. Completed special study on relocation of
the chemical feed points.
• Convinced city administrators to allow time for the
operating staff to remain at the plant to conduct
process control testing and to make plant adjust-
ments.
• Purchased additional laboratory supplies for con-
ducting jar tests.
• Extended filter backwash time to allow more com-
plete cleaning of filters.
• Staff investigated cost of monitoring raw water
quality with a turbidimeter and alarm at raw water
pumping station, an alarm on the existing tur-
bidimeter at the plant, and a streaming current
monitor with automatic control of coagulant
feeders.
• Consultant/State Site Visit (October 17-19,1989)
• Reviewed process control program.
• Conducted jar tests to evaluate alum replacement
products.
• Reviewed chemical teed calculations.
• Completed CCP assistance.
CCP RESULTS
Significant improvement in plant performance was
achieved during the conduct of the CCP. This is depicted
graphically in Figure 1. It is noted that while plant opera-
tion improved after reducing the plant flow rate and
eliminating the negative pressure on the filters in April,
performance remained erratic until process control, in-
cluding chemical adjustments, was implemented in July.
After July 1989, plant finished water turbidities remained
very consistent at about 0.1 to 0.2 NTU through the dura-
tion of the project. This consistent performance was
achieved even though raw water turbidities, shown in
Figure 2, varied widely. Plant finished water quality
remained below 0.3 NTU even when the raw water tur-
bidities reached 70 NTU because the operating staff con-
sistently monitored varying raw water quality and
responded by changing chemical feed rates. The plant
performance is especially impressive since influent tur-
bidities frequently exceeded values thought to be
treatable with direct filtration (e.g., 50 NTU). Another in-
dication of improved performance was that filter effluent
turbidity following a backwash did not exceed 0.3 NTU
and returned to 0.15 NTU within minutes after the wash.
The improved performance was achieved primarily
through improved process control activities and lowering
plant loadings that were more in line with unit process
capability. The primary process control tool utilized was
the jar test, which proved to be valuable in allowing the
operators to predict chemical doses required when raw
water quality varied. The jar test was used in conjunction
with filter paper to correlate results with the direct filter
plant conditions. The test provided a very accurate in-
dication of required chemical dose.
The plant staff became very adept at evaluating raw
water quality and adjusting chemical teed rates to
produce a high quality finished water on a continuous
basis. The staff exhibited a great deal of expertise and
professionalism during the CCP, and quickly learned
chemical feed calculations and implemented the neces-
sary process control activities.
The process control activities took additional operator
time at the plant. Prior to the CCP, operators would
check the plant daily; however, during the CCP,
operators were at the plant a minimum of 4 hours each
day. If plant raw water quality was changing rapidly,
operators would be at the plant making adjustments
whenever the plant was operating. City administrators
had to be convinced that the additional time was neces-
sary to achieve and maintain improved plant perfor-
mance.
Only minor physical plant modifications were required to
improve plant performance. The modifications included
removing a threaded plug from the filter effluent header
to relieve negative pressure on the filters and adding ad-
ditional alum and cationic feed points prior to an orifice
L-5
-------
Figure 1. Finished water turbidities for Plant No. 5.
0.9 -
o.e -
0.7 -
06
FUTURE REQUIREMENT
0.5 -
0.4 -
0.3 -
0.2
0.1
02-Apr-89 12-May-89
31-Jul-89
09-Sep-89 19-Oct-89
Figure 2. Raw water turbidities for Plant No. 5.
30 -
20 -
~~
~ a
02-Apr 12-May 21-Jun 31-Jul 09-Sep 19-Oct 28 Nov
L-6
-------
which was used as a flash mix. All minor modifications
were made by the plant staff.
The city administrators were favorably impressed by the
level of performance achieved by the plant. Major plant
(e.g., construction of a sedimentation basin) and raw
water intake modifications were being planned prior to
the successful implementation of the CCP. These major
modifications were placed on hold based on the ability of
the plant to perform within the SWTR requirements. The
intake modifications may eventually be made because
they will potentially reduce the turbidity load (e.g., draw
water from deeper points in the lake) to the direct filtra-
tion plant, allowing it to operate at higher hydraulic load-
ing rates.
CONCLUSIONS
Implementation of a CCP at water treatment Plant No. 5
was highly successful. The CCP proved that the plant
could achieve compliance with SWTR turbidity require-
ments without major capital improvements. City ad-
ministrators had planned on spending an estimated one
million dollars on construction of sedimentation basin
facilities and related improvements. After the CCP, they
decided to delay any construction until water demands
required the plant to be operated at higher rates. The
plant staff developed increased confidence that excellent
quality water could be produced despite high raw water
turbidities, and they developed a level of pride that did
not allow them to accept marginal finished water quality.
In addition, the jar test/filter paper procedure proved to
be a valuable process control tool that allowed accurate
selection of coagulant doses.
The city will have to continue the commitment to water
treatment in order to sustain the level of performance ob-
tained during the CCP. Continued production of high
quality water will require a commitment to allowing ade-
quate operator time at the plant to make necessary
chemical feed adjustments. If operators are not at the
plant whenever it is operating, a turbidimeter with alarm
should be installed at the raw water pumps to give the
operators continuous notice of raw water changes. The
use of a streaming current monitor that would automat-
ically adjust the alum feed rate if raw water quality chan-
ges could be investigated.
REFERENCES
1. U.S. EPA. 1984. Handbook - Improving POTW Per-
formance Using the Composite Correction Program
Approach. EPA/625/6-84-008. Cincinnati, OH: U.S.
Environmental Protection Agency, Center for En-
vironmental Research Information.
2. Renner, R.C., B.A. Hegg, and D.L. Fraser. 1989.
"Demonstration of the Comprehensive Performance
Evaluation Technique to Assess Montana Surface
Water Treatment Plants," Presented at 4th Annual
Association of State Drinking Water Administrators
Conference, Tucson, AZ.
3. U.S. EPA. 1989. Surface Water Treatment Rule.
Federal Register, Vol. 54, No. 124, U.S. Environmen-
tal Protection Agency, 40 CFR, Parts 141 and 142,
Rules and Regulations, Filtration/Disinfection, June.
L-7
a U.S. GCWe^ENT PRINTING OFFICE; 1SB1«
------- |