vvEPA
United States
Environmental Protection
Agency
Municipal Environmental Research
Laboratory
Cincinnati OH 45268
EPA-600/2-80-129
August 1980
Research and Development
Evaluation of
Operation and
Maintenance Factors
Limiting Municipal
Wastewater Treatment
Plant Performance
Phase II
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are: !
[
1. Environmental Health Effects Research
2. Environmental Protectiojn Technology
3, Ecological Research
4, Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7, Interagency Energy-Enyironment Research and Development
8. "Special" Reports i
9. Miscellaneous Reports j
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from poir-it and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution-sources to meet environmental quality standards.
This document is available to the ipublic through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-80-129
August 1980
EVALUATION OF OPERATION AND MAINTENANCE
FACTORS LIMITING MUNICIPAL
WASTEWATER TREATMENT PLANT PERFORMANCE
Phase II
by
Bob A. Hegg
Kerwin L. Rakness
James.R. Schultz
Larry D. DeMers
M & I, Inc., Consulting Engineers
Fort Collins, Colorado 80525
Contract No. 68-03-2572
Project Officers
John M. Smith
Francis L. Evans, III
Wastewater Research Division
Municipal Environmental Research Division
Cincinnati, Ohio 45268
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewedj by. the Municipal Environmental Research
Laboratory, U.S. Environmental [Protection Agency, and approved for
publication. Approval does not signify that the contents necessarily reflect
the views and policies of the U.S. [Environmental Protection Agency, nor does
mention of trade names or commericial products constitute endorsement or
recommendation for use.
ii
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•FOREWORD
The Environmental Protection Agency was created because of increasing
public and government concern about the dangers of pollution to the health and
welfare of the American people. Noxious air, foul water and spoiled land are
tragic testimony to the deterioration of our natural environment. The com-
plexity of that environment and the interplay between its components require a
concentrated and integrated attack on the problem. , .
Research and development is that necessary first step in problem solution
and it involves defining the problem, measuring its impact and searching for
solutions. The Municipal Environmental Research Laboratory develops new and
improved technology and systems for the prevention, treatment and management
of wastewater and solid and hazardous waste pollutant discharges from munici-
pal and community sources, for the preservation and treatment of public drink-
ing water supplies, and to minimize the adverse economic, social, health and
aesthetic effects of pollution. This publication is one of the products of
that research; a most vital communication link between the researcher and the
user community.
Many of the country's wastewater treatment plants do not meet design
expectations and NPDES permit standards. A research project was initiated to
identify, quantify and rank the causes of this poor performance by comprehen-
sive evaluations of 50 plants in nine western states. The identified highest
ranking causes of limited plant performance reflect an inability of in-plant
personnel to optimize process control and the performance of existing facili-
ties. Deficiencies in design features also ranked high. The performance of
each plant is typically limited by a unique combination of problems which
require individual identification and elimination. The Composite Correction
Program (CCP) was introduced and demonstrated. This approach to improving the
performance of existing facilities was conducted at selected facilities.
Areas of special evaluation include aerator and clarifier design, sludge pro-
duction in activated sludge plants, aerobic digester operation, reference
materials used in treatment plants, operator time and tasks before and after a
CCP, and the effects of toxic substances on well-operated treatment facilities.
Francis T. Mayo, Director
Municipal Environmental Research
Laboratory
111
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ABSTRACT
Many of the country's wastewater treatment plants do not meet design
expectations and NPDES permit standards despite vastly increased spending and
numerous improvement programs initiated in recent years. A two-phased
research project was initiated to identify, quantify and rank the causes of
this poor performance. Phase I of the project included comprehensive evalua-
tions of 30 plants in seven western states. In Phase II, the data base was
expanded to 50 plants in nine stateb. The identified highest ranking causes
of limited plant performance reflect an inability of in-plant personnel to
optimize process control and the performance of existing facilities. Many
design features also ranked high! among performance-limiting factors and
reflect the construction of many incomplete and marginally operable facili-
ties. Inadequate design and the high ranking of improper technical guidance
concerning process control by design engineers, regulatory personnel, equip-
ment manufacturers, training personnel and other authoritative sources indi-
cate the plant performance problem ijs not a uniquely local problem but rather
industry-wide.
Findings indicate the performan&e—ef--each plant is typically limited by a
unique combination of problems which require individual identification and
elimination. The Composite Correction Program (CCP) was introduced and demon-
strated in Phase I as a recommendeld approach to improve the performance of
existing facilities (EPA-600/2-79-034). These programs were conducted in
Phase II at selected facilities to, demonstrate improved performance and to
further illustrate the implementation of this approach.
i
Areas of special evaluation in the Phase II effort include aerator and
clarifier design, sludge production in activated sludge plants, aerobic
•digester operation, reference materials used in treatment plants, operator
time and tasks before and after a CGP, and the effects of toxic substances on
well-operated treatment facilities. :
[
This report was submitted in partial fulfillment of Contract No. 68-03-
2572 by M&I, Inc., under the sponsorship of the U.S. Environmental Protection
Agency. This report covers the period October 1, 1977 to April 1, 1979 and
the work was completed November 1979.
iv
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CONTENTS
Disclaimer . . . ii
Foreword iii-
Abstract . . . iv
Figures viii
Tables ix
Acknowledgement . . . . x
1. Introduction ..... . . 1
2. Conclusions 3
3. Recommendations .8
4. Research Approach i 10
Preliminary Plant Selection 10
Site Visits . 11
Comprehensive Surveys 11
5. Causes of Limited Plant Performance 13
Site Visit Facilities 14
Comprehensive Survey Facilities 16
Miscellaneous Evaluations 23
Fixed Film- Versus Suspended Growth Facilities , ... -23
Performance Versus Secondary Treatment Standards . . 25
Operations Costs 27
Electrical Energy 29
Staffing Considerations 31
Operator Certification 34
Summary 35
6. The Unified Concept . . . 36
Individual Correction Programs ... 37
Composite Correction Program .38
Unified Concept - Site Visit Versus
Comprehensive Evaluations 39
Implementation of a Composite Correction Program 40
7. Composite Correction Program Demonstrations .... 43
CCP at Plant 086 43
CCP Implementation . 44
Factors Limiting Performance 45
Performance . 46
Discussion 47
CCP at Plant 065 47
CCP Implementation 47
Factors Limiting Performance 48
Performance ........' 49
Discussion . . 49
v
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CONTENTS - Continued ;
CCP at Plant 074 . . .; 49
CCP Implementation 50
Factors Limiting [Performance 50
Performance 51
Discussion 51
CCP at Plant 097 ...[... 52
CCP Implementation . . 53
Factors Limiting Performance . 53
Performance . . .' 54
Discussion . . .! 54
CCP at Plant 085 .. J 55
CCP Implementation 55
Factors Limiting performance 55
Performance . . .• 56
Discussion . . .[ 56
CCP Application to thej Fifty Research Facilities 56
8. Selected Evaluations . . .1 60
Aerators 60
Activated Sludge Aeration Basins Preceeded
By Clarifiers ....... 60
Activated Sludge Aeration Basins Not Preceeded
By Clarifiers '. ". ! i ". '. ', '. ~. j\~j . ... 61
Fixed Film Facilities . . 63
Overall Aerator Evaluation 64
Clarifier Design 65
Design Limitations 65
Design Innovations 67
Sludge Production in Aptivated Sludge Plants
Without Primary Clarifiers 68
Activated Sludge Mass Control ..... 68
Sludge Production .... 69
Evaluation of Factors Affecting Sludge Production . . 72
Required Sludge Wasting Capacity '.'. ~.'. '. '. T~7 . . 75
Aerobic Digesters . . | 76
Plant Reference Literature ..... 78
Operation and Maintenance References 79
Laboratory References " '. '.'. i I T~ 83
Management References 83
Periodical Publications 83
Relationship Between Reference Material and
Plant Performance 83
Operator Time and Tasks . . . . . . . . 83
Plant 065 . I ; 85
Plant 086 . ; 85
Discussion . | 87
Effects of Toxics on Plant Performance ..... 88
Plant 065 . J 88
Plant 086 . | 88
Discussion .' .....91
References ..... 92
VI
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CONTENTS - Continued
Appendices
A. Location of Facilities and Type of Evaluation Conducted .... 93
B. Information Sheets for Site Visits and Comprehensive Surveys. . 95
C. Plant Evaluation Summary Forms . . 105
D. Plant Evaluation Summary for Site Visit Facilities (Phase II) .111
E. Plant Evaluation Summary for Comprehensive Evaluation
Facilities (Phase II) . -H7
F. Design Inadequacies Observed 123
G. Wastewater Treatment Cost Information 133
H. Individual Plant Performance Evaluations . . . 142
vii
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FIGURES
Number
Page
1 Study Area of the Western U. S. Contractor 2
2 Plant Selection Procedure J .10
3 Categories of Major Performa'nce-Limiting Factors 24
4 Average Costs for Wastewaterj Treatment in Fifty Facilities
Surveyed | 27
5 Plant Operations Costs for Major Plant Types and Selected
Flow Ranges • . 29
6 Correlation of Total Staff Size With Performance . 33
7 Correlation of Salaries With Performance 34
8 Correlation of Total Operations Costs With Performance .... 34
9 The Unified Concept for Achieving Optimum Plant Performance . 36
10 The Role of the Composite Correction Program in the
Unified Concept [ 38
11 Relationship of Major Types of Performance-Limiting Factors . 40
12 Implementation of a CCP . .1 41
13 Process Control Summary Sheet Used at Plant 086 44
14 Effluent BODc and TSS at Pla|nt 086 , .... 46
15 Organic Loading of Activated Sludge Plants Without Primary
Clarifiers | 61
16 Organic Loading of Fixed Film Facilities 64
17 Typical Activated Sludge Mas|s Control Data 69
18 Activated Sludge Mass Control 69
19 Sludge Production at Various; Wastewater Treatment Facilities . 72
20 Influence of Mean Cell Residence Time on Sludge Production . . 73
21 Influence of Food to Microorganism Ratio on Sludge Production. 74
22 Influence of Wastewater Detention Time in the Aerator on
Sludge Production ..... .74
23 Influence of Aeration Basin Organic Loadings on Sludge
Production 75
24 Variations in Sludge Wasted to Maintain Process Control ... 76
25 Automatic Supernating Device 77
26 Impact of Toxics on Sludge Activity at Plant 086 90
27 Impact of Toxics on Effluent Quality at Plant 086 91
Iviii
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TABLES
Number Page
1 Point System for Plant Evaluation Summary Weighing Table . . 13
2 Ranking of Factors Limiting Performance of 48 Site Visit
Facilities . . . 15
3 Ranking of Factors Limiting Performance for Fifty
Comprehensive Survey Facilities 18
4 Performance Evaluation of Fifty Comprehensive Survey
Facilities ..... 26
5 Summary of Cost Information by Type and Size of Facility . . 28
6 Power Usage for Fifty Comprehensive Survey Facilities ... 30
7 Staff Size and Costs for Fifty Comprehensive Survey
Facilities . 32
8 Evaluation of Operator Certification with Performance ... 35
9 Secondary Clarifier and Final Effluent Qualities for
Plant 074 52
10 Performance of Fifty Plants Evaluated Versus Secondary
Treatment Standards 57
11 Organic Loading at Activated Sludge Plants With
Primary Clarifiers 60
12 Organic Loading at Activated Sludge Plants Without
Primary Clarifiers . ...... 62
13 Organic Loading at Fixed Film Treatment Plants . 63
14 Characteristics of Secondary Clarifiers at the Fifty
Comprehensive Survey Facilities 66
15 Sludge Production Data 70
16 Sludge Production - Kg TSS per Kg BOD5 Removed 71
17 Average Operating Parameters During Sludge Production
Evaluations 73
18 Availability and Usage of Plant Reference Literature .... 80
19 Relationship of Reference Material Usage and Plant
Performance . 84
20 Operator Time and Tasks at Plant 065 86
21 Operator Time and Tasks at Plant 086 87
22 Impact of Toxic Substances on Fifty Comprehensive
Survey Facilities • 89
ix
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ACKNOWLEDGEMENT.
Appreciation is expressed to all managers, operators and other personnel
of the various wastewater treatment facilities who participated in the
research effort. Appreciation is afLso expressed to all state and EPA regula-
tory agency personnel who developed the various lists of possible research
facilities and who actively participated in various phases of the study.
The direction provided and assistance given by Mr. John Smith, Mr^ Ben
Lykins and Mr. Francis Evans, IIl| of the Environmental Protection Agency,
Office of Research and Development, Cincinnati, Ohio, are greatly appre-
ciated. !
x
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SECTION 1
INTRODUCTION
The Federal Water Pollution Control Act Amendments of 1972 (PL 92-500)
along with the 1977 amendments (PL 95-217) established goals for the water
quality of the nation's public waters and programs through which these goals
were to be achieved. As part of the overall program a minimum degree of
treatment, "secondary treatment," was established for the 25,000 existing and
also for any future publicly owned treatment works (POTW). Where secondary
treatment is insufficient to protect the receiving stream, provisions were
made in the 1972 Act to require more stringent treatment requirements.
The 1972 Act also established an expanded federal construction grants
program through which the construction of new POTW'S or upgrading of existing
POTW's was to be completed to meet the new water quality goals. However, the
1973, 1974 and 1975 editions of the U.S. Environmental Protection Agency's
(EPA) Clean Water Report to Congress showed that about one-third of all treat-
ment facilities constructed with federal grant assistance were not meeting
design effluent quality. In addition to these reports other sources have-
documented the plant performance problem (1, 2). In response to these find-
ings, EPA's Office of Research and Development initiated a three and one-half
year research program with the objective to identify, quantify and rank the
factors causing poor wastewater treatment plant performance.
Two consultants were selected to perform the research effort. Initially,
two 24-month contracts were awarded (Phase I), one to an Eastern U.S. Con-
tractor and one to the Western U.S. Contractor. Separate reports were pre-
pared describing Phase I findings (3,4,5). The work was continued through
subsequent 17-month contracts (Phase II) to the two firms in order to expand
the data base and research additional areas of special interest.
The objective of the research effort was to identify and rank the major
factors which limit biological wastewater treatment plant performance. This
objective was accomplished by conducting comprehensive evaluations of selected
wastewater treatment facilities. Plants were carefully selected rather than
chosen randomly because of the nature of the problem that prompted the study.
Recently constructed facilities (designed to be adequate for 20 years) were
expected to be operable without overwhelming design inadequacies or other
obvious problems that would preclude achievement of good performance. This
group of facilities were chosen for study to determine the performance
limiting factors. Facilities that were obviously overloaded, were inoperable
due to equipment problems or were incomplete because of inadequate process
design were not studied. The obvious nature of the problem in these
facilities are indeed performance limiting and must be addressed, but the more
1
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subtle causes of continued poor performance in operable facilities was the
emphasis of this research. In this category, facilities that met and did not
meet treatment requirements were studied. Evaluations of selected plants in
nine western states were conducted}, thirty during Phase I and twenty during
Phase II. The study area for the Western U. S. contractor is shown in Figure
1. '
Figure 1. Study area of the western U.S. contractor.
-
A special research approach was developed to identify the causes of poor
plant performance. As the causes were identified, it became obvious that a
complex interrelationship existed [between the problems in POTW's and the
potential solutions to those problems. An illustrative tool called the
"Unified Concept for Achieveing Optimum Plant Performance" was developed and
used to explain why a large number of POTW's do riot achieve desired perform-
ance. The "Unified Concept" also formed the illustrative basis for an
approach which can lead to improved performance from POTW's. The approach
termed a Composite Correction Program, focuses on all the problems at an
individual plant, and its effectiveness was demonstrated at six facilities.
In addition to the overall evaluation, several areas typically felt to.be
specific causes of poor performance were evaluated including: reference mater-
ial, toxic substances, sludge production, clarifier design, aerator loadings,
aerobic digesters, and operator activities.
This report documents findings of the Western U.S. Contractor for both
Phase I and Phase II activities. Data collected in Phase I (5) have been
incorporated into this report so ithat the entire data base for the fifty
facilities could be used to develop the conclusions and recommendations. A
separate report describing the results for the Eastern United States has been
prepared by the eastern area contractor (3).
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SECTION 2
CONCLUSIONS
1. Performance limiting factors at publicly owned wastewater treatment facil-
ities were identified and ranked by conducting comprehensive evaluations
at 50 plants.
A. Through a formal screening process, inoperable plants with major
hydraulic or organic overloads, heavy industrial loadings, excessively
poor maintenance, or major administrative limitations were eliminated
from study.
B. Of the factors evaluated, improper operator application of concepts
and testing to process control received the highest ranking. Inade-
quate sewage treatment understanding was ranked second. Additional
training needs were indicated, but restructured training activities
are necessary.
C. Improper technical guidance was ranked third and occurred in half of
the plants evaluated. A general re—evaluation of the approach taken
to the dissemination of operations oriented information, especially
that relating to process control, is necessary and must include
increased accountability for guidance given by "authoritative"
sources.
D. Inadequate design features comprised six of the top ten performance
limiting factors. Additional emphasis to_ provide better designed
wastewater treatment plants is required.
E. Performance limiting factors at fixed film facilities were more design
oriented, with inadequate capability to convert soluble BOD5 to a
settleable solid being the leading problem. Operation oriented prob-
lems were more frequent at suspended growth plants.
2. Thirty-seven of 50 facilities evaluated did not consistently meet
Federally defined secondary treatment standards.
A. The inability of these plants to meet standards was not related to
loading since no plant exceeded its design loading., The mean hydraul-
ic loading was 66 percent of design.
B. Twenty-seven of 37 plants could potentially meet standards by address-
ing major performance-limiting operations oriented factors, and minor
administration, maintenance and design factors.
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C. Ten of 37 plants violating standards have major design problems that
must be corrected through plant expansion or upgrading. Of these ten
facilities, nine were fixed film facilities.
D. Suspended growth plants could be brought into compliance without major
capital improvements, but somewhat higher 0 & M costs may be necessary
primarily due to increased [sludge handling needs.
I
3. Relating specific factors to plant performance resulted in only limited
correlations being established.!
A. Larger staff size, higher staff salaries, and higher total operations
costs did not correlate with good plant performance.
B. A higher level of certification by the chief operator did promote
better plant performance, but only 40 percent of the "A" and "B" cer-
tified operators' plants met standards.
4, A "Unified Concept for Achieving Optimum Plant Performance" was developed
to describe the interrelationship of performance-limiting factors and the
methods used to improve plant capabilities.
A. Two different categories ! of programs using distinctly different
approaches to achieving desired plant performance were described.
1) Individual correction programs are implemented with the purpose of
addressing and eliminating specific factors or groups of factors
at a large number of facilities and do not address the unique com-
bination of factors at various individual facilities.
i
i
2) A Composite Correction Program is implemented at a single facility
with the purpose of identifying and eliminating all limiting
factors to achieve a desired level of performance.
I
Major factors limiting performance in the design, maintenance and
administration areas tend to cause a plant to be incapable of meeting
performance objectives. These plants must achieve an operable status
in order to pursue the goal of optimum performance. Operation prob-
lems represent the remaining step between an operable facility and the
goal of a good, economical plant effluent.
i.
Adoption of the basic principals described in the "Unified Concept"
would allow a coordinated and directed effort to be. developed for the
groups that influence plant performance. (i.e. operating personnel,
municipal officials, regulatory agency personnel, engineering consul-
B.
tants, equipment suppliers,
etc.)
5. If properly implemented, the Composite Correction Program (CCP) approach
can achieve an improvement in Jplant effluent quality at many treatment
facilities without major capital expenditures.
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A. Implementation of four CCPs during the research project resulted in a
dramatic improvement in plant effluent quality.
B. Significant potential for improving performance through implementa-
tion of CCP's exists. Without major facility modifications, 27 of 37
plants found violating standards could be brought into compliance.
Additionally, the 8005 and TSS discharged to receiving streams by
38 plants could be reduced by 1020 metric tons/year (1120 ton/year)
and 1190 metric tons/year (1315 tons/year), respectively.
C. The CCP approach can reduce the improper technical guidance factor
noted if personnel conducting a CCP are held accountable in attaining
the objective of a CCP: namely to achieve desired performance at a
particular facility.
^ ' ' •
D. Further incentives (i.e., enforcement) are necessary to encourage
administrators to investigate the CCP approach. Presently, a negative
incentive for good performance exists in that poor performing plants
are "rewarded" with substantial construction grant funds to build new
facilities.
6. A special evaluation was made for aerators and a positive correlation
between aerator loading and plants meeting standards was noted.
A. Conservative aerator loading for suspended growth facilities helps to
improve plant performance, but is not a guaranteed solution nor is it
cost effective.
B. The performance of activated sludge plants violating standards could
be improved significantly through better operation and often could
adequately treat additional wastewater without major capital improve-
ments.
C. Fixed film plants with low aerator organic loadings had a better per-
formance record, while more heavily organically loaded f'acilites could
not achieve good performance without major capital improvements.
7. A special evaluation of secondary clarifiers indicated that significant
i additional capacity remains in existing units. Some design and operation-
al factors were observed to limit or enhance utilization of this capacity.
, A. Inadequate utilization of the clarifier surface for overflow with
resulting hydraulic limitations was noted in many clarifiers.
B. At some small facilities a clarifier sludge scraper mechanism was not
provided and inadequate sludge removal occurred. Better operation
priorities and/or major design modifications are necessary at these
plants.
C. Deep final clarifiers [4.5 m (15 ft)] were observed to aid plant per-
formance and process control capability.
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D. Clarifiers with separate rapid withdrawal return sludge mechanisms and
a scraper used to feed sludge to a hopper bottom were advantageous in
allowing partial separation; of activated sludge and heavier solids for
plants without primary clarifiers.
j
8. A special evaluation was made of sludge production in activated sludge
plants without primary clarifiers.
A. Documented sludge production ratios for single aeration and two stage
aeration activated sludge [plants varied from 0.6 kg TSS/kg BODc to
1.1 kg TSS/kg BODij removed, and were highest for two stage aeration
(contact stabilization) plants.
B. Documented sludge production ratios did not change significantly with
varying mean cell residence times, food to microorganism ratios,
wastewater detention times Jin the aerator or aeration basin organic
loadings. ;
i
C. Most sludge handling systems were grossly undersized because design
sludge production values were severely underestimated.
r
9. A special evaluation was made ! of aerobic digesters at activated sludge
plants.
A. Aerobic digester sludge solids were frequently recycled back to the
activated sludge treatment process.
I
B. None of the aerobic digester automatic supernating devices performed
satisfactorily.
C. Batch operation of aerobic| digesters provided the best control over
operation and performance, j At some plants batch operation was diffi-
cult because of inadequate structural integrity of digester walls.
i
D. Inadequate aerobic digester size was noted repeatedly. Inadequately
sized digesters caused increased operations activities in the form of
frequent supernating requirements, digester foaming problems, and
additional efforts for removing undigested sludge for ultimate sludge
disposal.
E. Final effluent quality of operating facilities with inadequately sized
digesters can be improved by hauling partially digested sludge.
I
10. A special evaluation was made of the availability and usage of plant
reference literature.
s
•• I
A. Plant specific 0 & M manuals were the most available and widely used
reference source. Despite their use, only 30 percent of those plants
met standards indicating that 0 & M manuals are limited in their
ability to provide a basis for the operator to improye plant perform-
ance . 1
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B. Other publications used ranked in the following order: New York
Manual, Sacramento Course, WPCF MOP5, Texas Manual, and WPCF Studybook
for Wastewater Operator Certification. The highest ranking process
specific publication used was Operation Manual, Anaerobic Sludge
Digesters (EPA 430/9 - 76-001).
C. Other specific areas of highest reference usage were as follows:
Lab Reference - Standard Methods
Management Reference - Safety in Wastewater Works
Periodical Publication - WPCF "Highlights"
11. A special evaluation was made of operator time and tasks at two plants
prior to and after plant standards were consistently met.
A. Adequate manpower is required but without proper training and usage of
the manpower good performance will not occur.
B. Increased operator time for process control activities at two smaller
activated sludge plants was required to improve plant performance.
12. A special evaluation was made of the effects of toxics on biological
wastewater treatment process performance at two facilities where CCP's
were conducted.
A. A short term effect of toxics was that plant effluent quality deteri-
orated. A long term effect was that poor sludge characteristics
developed and were slow to recover because of the long time associated
with biological system response.
B. Many problems with plant operations associated with poor process con-
trol are unjustifiably blamed on toxics.
C. When a true toxic problem exists, finding and eliminating the source
should receive a high priority from plant administrators and staff.
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1.
2.
SECTION 3
RECOMMENDATIONS
Improve design of wastewater treatment facilities, with special considera-
tion to the high ranking design features observed.
A. Consider conservative organic loading rates in the design of fixed
film biological reactors.
B. Encourage plant flexibility ^hich would allow bypassing of ponds fol-
lowing mechanical plants and flexibility to operate activated sludge
plants in various modes.
C. Include flow rate measurement and control features in the design of
return activated sludge flow
systems,
D. Improve secondary clarifier design by considering features which opti-
mize surface area development, provide for greater sludge storage and
compaction (i.e. depth), and provide separate return and waste sludge
removal mechanisms.
E. Include adequately designed |sludge handling facilities in all plants.
Use realistic sludge production estimates as a basis for design.
F. Design aerobic digesters for batch operation and eliminate in-tank
automatic supernating devices.
G. Recognize that ultimate sludge disposal can directly affect effluent
quality. Design alternatives and flexibility into ultimate disposal
systems. i
j
Structure information dissemination and training programs to emphasize the
highest ranking factors limiting plant performance.
A.
B.
Recognize that on-site training is the most effective way to develop
an operator's capability to'properly apply wastewater treatment con-
cepts to process control. Seek to develop operators' skills through
technical guidance at their respective facilities.
Encourage operating personnel!, to improve sewage treatment understand-
ing through budget support for off-site training and certification.
Expand training of design and review engineers in plant operations and
process control through classroom training plus guided inplant opera-
tions experience. i
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D. Use persons thoroughly aware of wastewater treatment process require-
ments to review and correct inaccurate, incomplete and misleading
training information.
E. Improve qualifications and training of private and governmental per-
sons providing operations technical assistance, in order to avoid the
frequent occurrence of improper technical guidance. Training should
include in-plant operations experience where personnel are in a posi-
tion to be held accountable for process oriented recommendations.
3. Implement the composite correction program (CCP) approach on a broad scale
to improve the performance of wastewater treatment facilities.
A. Develop an awareness of the broad range of factors (i.e., administra-
tive, design, operation and maintenance) that can limit POTW perform-
ance. Realize that all these problems must be addressed at an indi-
vidual plant to achieve optimum performance.
B. Recognize that many factors limiting plant performance are beyond the
plant operator's control (i.e., design and administrative factors).
C. Verify performance potential of existing facilities by requiring a
comprehensive evaluation which assesses performance problems from the
basis of a thorough understanding of process requirements. Implement
a CCP to develop full plant potential. '
D. Require extended and process oriented technical assistance services at
new or upgraded facilities with the objective of achieving desired
performance.
E. Implement incentives such as enforcement to encourage improved per-
formance at facilities not achieving design or permit standards.
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SECTION 4
RESEARCH APPROACH
PRELIMINARY PLANT SELECTION
Plants selected for evaluation! had to meet general criteria stipulated
for the research effort, such as: j geographical area, biological wastewater
treatment facilities in the 0-37,85p cu m/day (0-10 mgd) size range, plants
not severely overloaded, plants which had all major units operable, and plants
not involved in enforcement action. To find facilities which met the selec-
tion criteria, several screening steps were used. The plant selection proce-
dure is depicted in Figure 2.
GENERAL SCREENING
IAU. FACILITIES 1
WESTERN U.S. AREA
BIOLOGICAL PLANTS
O*1O MGD SIZE
FLOWS DESIGN
ORGANIC LOADING S DESIGN
NO ENFORCEMENT PENDING
PLANTS SELECTED
ISO FACILITIES!
"OPERABLE" FACILITIES
INTERESTED OPERATORS
PRELIMINARY SCREENING
1271 FACILITIES)
REGIONAL EPA DESIRES
STATE AGENCY DESIRES
UNIQUE DESIGN INCLUDED
TYPE OF FACILITY
SIZE OF FACILITY
SITE VISIT SCREENING
IBS FACILITIES!
• LOCAL COOPERATION
• OPERATOR AVAILABILITY
• EXCESSIVE I/I
• MAJOR DESIGN DEFICIENCIES
• ALL UNITS IN SERVICE
PLANTS
REJECTED
(1731
PLANTS
REJECTED
1481
Figure 2. Plant
selection procedure.
Personnel in EPA Regions VII arxl VIII and in nine state regulatory agen-
cies were informed of the general screening criteria and asked to provide sug-
gested plants for study. A total of 271 plants were suggested. Using tele-
phone discussions and considerations of location, size, type of process, and
plant loading, 173 of these facilities were eliminated from further considera-
tion.
10
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SITE VISITS
Site visits were made at 98 facilities. Typically, half-day visits were
made by two sanitary engineers with experience in identifying performance-
limiting factors. Based on the site visit findings, 48 facilities were elmi-
nated from further study. Problems which caused the elimination of facilities
included such factors as inoperability of the facility, equipment problems and
extreme overloading problems. A few facilities were eliminated because town
officials or plant personnel expressed a desire to not participate in the
study. Some very small facilities were rejected because plant personnel were
not available. Some facilities were rejected because facilities of that type
and size had been previously evaluated.
The scope of the site visits included formal documentation of general
information (design flow, population served, receiving stream, etc.), process
description (wastewater and sludge flow schematic) and plant operation and
maintenance characteristics (number of operators, lab facilities available,
plant maintenance completed, etc.). An investigation checklist used for site
visits is included in Appendix B. Additional documentation included factors
which were noted to limit performance and the reasons the plant was not
selected for further study. Plants for which a site visit was conducted are
referenced in Appendix A.
COMPREHENSIVE SURVEYS
Using the plant selection procedures outlined, fifty facilities were
identified for comprehensive evaluations. A list of facilities surveyed is
included in Appendix A. Each evaluation was typically conducted with one and
one-half to two man-weeks of effort over a four to ten-day period. Persons
conducting the surveys were sanitary engineers with experience in plant opera-
tions. The evaluation team worked with plant personnel to temporarily address
obvious and controllable performance limiting problems at the plant so other
less apparent problems could be identified. Each evaluation was followed by a
written report which explained the problems identified during the survey.
Factors which limited performance were discussed under four general topics:
administration, maintenance, design and operation. The discussion in the text
of the reports was limited to areas in which conclusions and recommendations
were made. Implementation of recommendations made to the city or sanitation
district were completely voluntary.
Two appendices were included in all survey reports. One appendix con-
sisted of Survey Information Sheets, which were used to provide a common data
base and a thorough documentation of diverse information about each facility.
An example copy of these sheets is included in Appendix B. The second appen-
dix in the preliminary survey reports consisted of a completed EPA Inspection
Form 7500-5. Copies of each report were distributed to the facility surveyed,
the state pollution control agency, the regional EPA office and the EPA
research project officer. Copies were also given to the facility design engi-
neer upon request from the city.
11
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Plants chosen for preliminary! surveys represented a cross-section of
facility types and sizes within the desired plant flow range of 0-37,850
cu m/day (0-10 mgd). Research was limited to this flow range because the
majority of POTW's in the United States falls within this range. Results
obtained from evaluations of plants' within this size range were expected to
have broad applicability. Additionally, it was the intent of the research
project to identify the reasons why jmany recently upgraded facilities were not
in compliance with current treatment requirements (1, 2). Facilities chosen
for comprehensive evaluations were "operable" facilities selected to meet
these requirements. Results for the comprehensive evaluations are thus biased
away from obvious performance limiting factors such as hydraulic and organic
overloading. '
A more extensive discussion ofjthe research approach, including an exam-
ple survey, was presented in the Phase I report (5).
12
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SECTION 5
CAUSES OF LIMITED PLANT PERFORMANCE
An in-depth evaluation was made at each facility to determine what fac-
tors were limiting performance. Results of each evaluation were documented on
Plant Evaluation Summary Forms. A copy of these forms along with a definition
of terms used is included in Appendix C. The Plant Evaluation Summary was
developed as part of the research effort and consisted of two parts, a weigh-
ing table and a ranking table. The weighing table included seventy different
factors that could possibly limit plant performance. This list of factors was
composed of items from various inspection forms, troubleshooting lists and
other sources. To achieve a high degree of consistency and objectivity for
the research, each factor was specifically defined. During the plant evalua--
tions each factor was evaluated and assigned a numerical weight according to
the schedule in Table 1.
TABLE 1. POINT SYSTEM FOR PLANT EVALUATION SUMMARY WEIGHING TABLE
Weighing
Points
Adverse Effect of Factor on
Plant Performance
0
1
2
No significant effect on plant
performance.
Minor effect on plant performance.
Minimum indirect effect on plant
performance on continuous basis or
major direct effect on plant per-
formance on a periodic basis.
Major direct effect on plant per-
formance .
The second part of the Plant Evaluation Summary, the ranking table, was
used to put the factors which received points in priority ranking. Only fac-
tors which received two or three points were included in the ranking table.
Ranking tables for all facilities evaluated during Phase II are included in
Appendix D and E. Ranking tables for facilities evaluated during Phase I have
been previously published (5).
The Plant Evaluation Summary was originally developed to quantify and
rank the factors limiting performance only at the facilities where comprehen-
13
-------
sive surveys were conducted. However, because it was found that a meaningful
amount of information especially for obvious performance-limiting problems,
could be obtained during the half-dky site visits, the Plant Evaluation Sum-
mary was also completed for the 48 facilities where site visits were con-
ducted.
SITE VISIT FACILITIES
Site visits were conducted at 98 facilities as part of the plant selec-
tion process. Fifty of these facilities were selected for comprehenisve eval-
uations. Results from the 48 site visited facilities differed from the com-
prehensive evaluation results due to limited time that was spent for each
visit, and the nature of the plant selection criteria. Whereas, more of the
subtle factors were determined during the week-long comprehensive surveys,
only the more obvious factors were documented during the site visits. There-
fore, only the factors that warranted a weight of two or three points were
listed. The ranking table completed' for each site visit facility is included
in Appendix D. \
I
The combined ranking of performance limiting factors for all site visit
facilities is shown in Table 2. Thirty-three different factors which were
given two or three points are included. Each factor was ranked according to
the cumulative number of points received for the 48 site visits. Also shown
are the Plant Evaluation Summary reference number for each factor, the number
of times each factor occurred, the number of times a factor ranked No. 1 at a
facility and the number of plants fo|r which each factor was given a weight of
three points and two points. !
Each site visit typically included discussions with plant administrators
as well as in—plant personnel. During such discussions responsiveness to
plant needs was assessed. Plants with unresponsive administrators were elimi-
nated from further study. In this manner, administrative policies received a
high ranking in site visit facilities (ranked number 8), but was not nearly as
prevalent in facilities where comprehensive evaluations were conducted.
The design aspects of each plant were evaluated based on unit sizes, con-
trol features and process completeness. Nineteen of the top 33 factors were
design oriented. It was concluded that for many site visited facilities major
and/or minor design modifications were required before an operable plant could
be provided.
I
Some site visit facilities had jserious,equipment malfunction problems or
lacked preventive maintenance and housekeeping programs to the point that
operability of the facility was questionable. Site visits were often too
short to identify if these obvious problems were actually a result of admini-
strative or in-plant operator problems. However, the inoperable condition of
these facilities eliminated them from further evaluation.
An evalution of the operation |of many site visit facilities showed an
obvious lack of application of even basic concepts and test results to process
control. However, there was not sufficient time to evaluate other more subtle
14
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operations related factors such as improper technical guidance, inadequate
operator aptitude, inadequate training, etc.
It was concluded that the performance of site visit facilities was
limited by obvious design, administration and maintenance factors that hinder-
ed those facilities from obtaining an operable status. In these facilities,
evaluation of performance was limited and further study under the scope of
this research was not warranted. '
COMPREHENSIVE SURVEY FACILITIES
The results for the comprehensive surveys represent reliable and in-depth
insight into the problems which prevent many operable facilities from achiev-
ing desired levels of performance.j This is true because of the nature of the
research approach, the length of tame spent at each facility and the experi-
ence possessed by the persons conducting the research. Additionally, compre-
hensive survey facilities were selected plants and the problems identified
represent in-depth types of factorb that might not have been as predominantly
exhibited by plants randomly chosen.
The factors which ranked highest for Phase I did vary somewhat from those
factors which ranked highest in Phase II. The ten highest ranking factors for
the two phases are as follows: j '..',..
Phase I (30 plants) ;
1. Operator Application of 1.
Concepts ...
2. Sewage Treatment Understanding 2.
3. Technical Guidance I 3.
4. Process Control Testing , 4.
5. Sludge Wasting Capability i 5.
6. Process Flexibility 6.
7. Process Controllability 7.
8. Clarifier ', 8.
9. Sludge Treatment 9.
10. Aerator 10.
Phase II (20 plants)
Operator Application of
Concepts ...
Infiltration/Inflow •' ,
Sludge Wasting Capability
Technical Guidance
Process Controllability <
Aerator
Sewage Treatment Understanding
Process Control Testing
Process Flexibility
Ultimate, Sludge Disposal
In the Phase II results infiltration/inflow and ultimate sludge disposal
ranked in the top ten in place of clarifier and sludge treatment
factors were included in the top ten for both phases, however, the
ranking of these factors varied from the first phase to the second.
application of concepts and testing to process control ranked first
phases. Operator, as used here, represents the person or persons in
ible charge of process adjustments iwithin the plant.
Eight
relative
Operator
in both
respons-
The most significant change between Phase I and Phase II results appears
to be the high ranking of Infiltration/Inflow in Phase II. Infiltration/
Inflow ranked only eighteenth in iPhase I, but ranked second in Phase II.
Probably the greatest factor influencing the higher ranking of I/I was that
Phase II research was concentrated more in the eastern portion of the study
16
-------
area. In these states the collection systems were .typically older and precip-
itation is significantly greater than in the states in the western portion of
the study area. \
For purposes of this report, the results from ,the Plant Evaluation Sum-
maries for Phase I and for Phase II were combined for all fifty facilities at
which comprehensive surveys were conducted. An average of thirteen and a
range four to thirty performance-limiting factors were identified at individu-
al facilities. As was concluded in the Phase I research effort, it is not
believed that the actual ranking of individual factors is particularly impor-
tant. The interrelationship among factors are believed more important, as
well as the understanding that at least four.performance limiting factors were
identified at each facility studied, including those that met secondary treat-
ment standards. The ranking of performance-limiting factors for all fifty
facilities is shown in Table 3. Sixty-two of the 71 factors evaluated
received at least one point in at least one plant.
The highest ranking factor limiting performance at facilities surveyed
was inadequate operator application of concepts and testing to process con-
trol. This factor was identified in 48 of fifty facilities surveyed and was
the leading cause of poor performance in fifteen facilities. Improper opera-
tor application of concepts was ranked when incorrect control adjustments
and/or incorrect control test interpretation occurred. This factor was ranked
number one in some facilities which had major design problems also. Thus,
proper application of concepts required that an operator recognize when the
plant design legitimately limited his capability to apply basic fundamentals
of wastewater treatment to process control. At some plants, operator ingenu-
ity was observed to overcome minor plant design limitations and was beneficial
to improving plant effluent quality. Operator application of concepts rated
high in many plants because operators were observed to understand the mechan-
ics of process control features, but did not relate available operational
controls to the needs of the biological system.
The second highest ranking performance limiting factor was a general lack
of sewage treatment understanding. This factor was identified in, 28 of fifty
facilities surveyed and was the leading cause of poor performance at six
facilities. The two leading causes of poor plant performance, operator appli-
cation of concepts and sewage treatment understanding, are similar, but dif-
ferentiate between levels of operator abilities. Sewage treatment understand-
ing refers to a lack of general knowledge concerning sewage treatment.
The high rankings of inadequate operator application of concepts and
testing to process control and inadequate sewage treatment understanding indi-
cate that present efforts toward accomplishing the goal of developing opera-
tors with desired capabilities are.not being achieved. These findings suggest
that a change may be necessary in the approach to operator development before
significant improvement in plant performance will occur.
Improper technical guidance was the third highest ranking performance
limiting factor occurring at 25 of the fifty plants surveyed and was the lead-
ing cause of poor performance in six facilities. Improper technical quidance
17
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was strongly suspected in additional facilities, but was not documented as a
problem unless the specific source of the misinformation was determined. Mis-
information was provided by authoritative sources including design engineers,
state and federal regulatory agency personnel, equipment suppliers, operator
training staff and other plant operators. A detailed evaluation of each
source of improper technical guidance was developed in the Phase I report (5).
A general observation that applies to each source of improper technical
guidance is 'related to the characteristics of biological treatment systems.
It was observed that in instances where correct operations recommendations
were made for a particular situation, they were often incorrect at a later
date because of changes in the biological process. Operators continued to
make adjustments under the original (recommendations since many of them did not
completely understand the biological process and the limits to the applica-
tion of the recommendation. Based on this observation, it was concluded that
a general re-evaluation of the approach taken to the dissemination of techni-
cal guidance is necessary, and should include increased accountability by
authoritative sources for the guidance that is given.
i
Another important aspect of the improper technical guidance factor is
that it extends the source of poor [plant performance beyond the plant opera-
tions staff. Authoritative sources' have limited the capability of operators
to attain adequate sewage treatment understanding by providing misinformation.
Additionally, misinformation is harmful in that it sidetracks the search for a
legitimate solution to a plant performance problem.
i
Inadequate sludge wasting capability was the fourth highest ranking
factor and was documented in 26 facilities. Sludge wasting capability was
rated as having a major impact on plant performance (i.e., 3 points) at nine
facilities. Lower ratings of one br two points were assigned at seventeen
facilities where waste capacity was marginal or sludge flow measurement and/or
control were inadequate. Because of the high ranking of this factor, sludge
production for small activated sludgje plants is given special consideration in
Section 8. !
Inadequate Process Control Testing and inadequate Process Controllability
tied for fifth among the performance limiting factors. Each was documented in
32 facilities, but neither was considered to have a major direct effect on
plant performance (i.e., given 3 points) and neither was ranked as the number
one performance limiting factor at [any facility. Inadequate process control
testing was never considered a leading cause of poor performance because it
was usually interpreted as a secondary factor to an operator's ability to
understand and/or apply treatment concepts to process control.
•
Inadequate control and measurement of return activated sludge flow was
the most frequent reason for rating!the process controllability factor. Only
six of 36 activated sludge plants surveyed had both good measurement and con-
trol of return sludge flow rates. These findings indicate a general misunder-
standing of the importance of return sludge flow control.
&
The seventh ranked factor limiting plant performance was inadequate pro-
cess flexibility. Process flexibility is the availability of valves, piping
22
-------
and other appurtenances required to operate in various modes or to include or
exclude existing processes as- necessary to optimize performance. Inadequate
process flexibility limited performance at twenty-four plants surveyed and was
the leading cause of poor performance at three facilities. At these three
plants a dramatic improvement in plant effluent quality could have been
achieved with improved process flexibility.
Deficient aerators and infiltration/inflow tied for the eighth and ninth
ranking performance limiting factors. Aerator, as used in this evaluation,
means the facility used for the conversion of soluble organic matter into
settleable organic matter. Examples of aerators as used in this context are
trickling filters, activated sludge aeration basins, rotating biological con-
tactors and activated bio-filters. Aerators were assigned points (i.e.,
received 1, 2 or 3 points) when they exhibited limited capability to convert
dissolved and colloidal organic matter to settleable solids or encouraged the
development of an unstable or difficult to control sludge. Performance limit-
ing aerators were found in seventeen facilities surveyed and were the number
one cause of limited performance in four facilities. Twelve of the seventeen
facilities for which an indequate aerator was noted as a factor limiting per-
formance were fixed film facilities, including trickling filters, rotating
biological contactors and activated bio-filter systems. The other five facil-
ities were activated sludge plants exhibiting a variety of aerator deficien-
cies. These included inadequate oxygen transfer capability, under-sized aera-
tion basins and incomplete or inadequate separation of contact and reaeration
compartment in contact stabilization plants.
Excessive I/I was documented to be a performance-limiting factor in
twenty-four facilities surveyed. I/I caused short-term operating and perform-
ance problems in many facilities, but was not considered the most critical
factor limiting performance relative to the numerous design and/or process
control related factors which were observed to be causing serious performance
problems on a continuous long-term basis. I/I problems remain as a periodic
factor limiting plant performance and must continue to be addressed.
The tenth ranked factor was inadequately designed secondary clarifiers.
Performance limiting clarifiers were documented in sixteen facilities, and
were the most significant performance limiting factor in two facilities sur-
veyed. .The secondary clarifier factor was identified when poor clarification
occurred due to the size of the clarifier, placement of the weirs, weir length
or type of clarifier. The secondary clarifier factor was not noted as a per-
formance limiting factor when solids loss due to a slow settling sludge (i.e.,
bulking sludge) was observed. Glarifier design is discussed in greater detail
in Section 8.
MISCELLANEOUS EVALUATIONS
Fixed Film Versus Suspended Growth Facilities
An evaluation was made of the major performance-limiting factors (re-
ceived 2's or 3's) for the two general types of facilities surveyed: suspend-
ed growth and fixed film. Activated sludge facilities and all facilities
using modifications of the conventional activated sludge process were
23
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classified as suspended growth facilities. Trickling filter, rotating
biological contactor and activated ibio-filter facilities were classified as
fixed film facilities. For each plant type thg percentages of performance
limiting factors was determined 'for the categories of administration,
maintenance, design and operation. The results of this evaluation are
illustrated in Figure 3.
MAINTENANCE
^%
MAINTENANCE
SUSPENDED GROWTH
FIXED FILM
Figure 3. Categories of major performance-limiting factors.
At fixed film facilities the majority of performance limiting factors
identified were design oriented. Within the design category, inadequate
aerator capability occurred most often. Generally, fixed film facilities
which had very low organic loadings! consistently met standards. Those that
had intermediate and higher loadings generally did not meet standards even
with good operation. Approximately! one third of the major factors limiting
fixed film facility performance were operations oriented. Most prevalent
among these was operator application of concepts and testing to process
control. Operational changes could improve the performance of these
facilities.
i
At suspended growth facilities^ operations problems were more prevalent
than design problems. Together thejse categories accounted for 90 percent of
the factors identified. In the operations category, the factors of improper
operator application of concepts, inadequate sewage treatment understanding
and improper technical guidance were most common. Most common among the
design problems were inadequate design for I/I, inadequate process flexibility
and controllability, and inadequate design of sludge wasting and disposal
facilities. Most design problems identified were closely related to providing
process control capability. Inadequate operations understanding by designers
and regulatory review personnel. These same persons were repeatedly
identified as sources of improper technical guidance.
24
-------
Maintenance factors received a low ranking for both suspended growth and
fixed film facilities. This low ranking was expected since facilities with
obvious poor maintenance were not selected for evaluation. Also, many opera-
tors possessed better maintenance than process control skills. Additionally,
maintenance has been given priority since a maintenance problem is more
obvious.
Performance versus Secondary Treatment Standards
An evaluation was made to determine if the facilities surveyed met
secondary treatment standards as defined in CFR 38-159. A facility was con-
sidered to be meeting standards even with isolated violations of the limits
for BODc and TSS, if it was believed the violations were a legitimate excep-
tion to normal performance. For example, a facility that averaged 12 mg/1 for
effluent BODc and 17 mg/1 for effluent TSS for the year, but recorded month-
ly averages in the thirties for one or two months was considered to be meeting
standards. On the other hand, a facility that produced an otherwise excellent
effluent but bulked solids only two afternoons a week was not considered to be
meeting standards.
Thirty-seven of the fifty facilities evaluated did not meet minimum
secondary treatment standards even though the mean hydraulic loading for these
plants was 66 percent of design flow. Apparently the ability of plants to
meet secondary standards was not generally related to plant loading.
It should be noted that performance-limiting factors were identified in
facilities that met standards since many of these facilities WBTB not being
operated at their optimum performance levels. In the thirteen plants that met
standards consistently, an average of 2.8 major factors per plant were identi-
fied. In the 37 plants that did not meet standards consistently, an average
of 5.2 major factors per plant were identified. The important observation was
that a combination of factors existed in each plant.
The performance evaluation included an estimation of the improvement in
effluent quality that could be achieved by eliminating all factors which would
not require major capital expenditures. The results for individual facilities
are included in Appendix H. The projected improvement would allow many
facilities which are currently in violation to meet secondary standards.
Individual facilities that meet secondary standards, facilities that could
meet secondary standards without major capital improvements and facilities
that would likely require major capital improvements to meet secondary
standards are identified in Table 4.
Thirty-seven of fifty plants surveyed did not meet secondary standards.
Of these, 27 were limited primarily by factors that could be eliminated by
addressing administration, maintenance and process control problems. These 27
plants could potentially meet secondary standards without a major design and
construction effort. Ten facilities would require a major plant expansion to
meet secondary standards. Most of these would also require improved opera-
tions. This evaluation indicated that performance could be improved signifi-
cantly at existing treatment facilities.
25
-------
TABLE 4 . PERFORMANCE EVALUATION OF '50 COMPREHENSIVE. 'SHRVKY FACILITIES
Plant
No . Date
002
007
012
013
014
015
019
020
021
022
024
026
027
028
029
032
034
035
036
038
039
040
041
047
048
050
051
052
053
055
060
061
062
063
065
066
068
•069
070
074
075
077
080
082
085
086
092
093
095
097
1975
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1978
1976
1976
1977
1976
1976
1977
1977
1977
1977
1977
1977
1977
1977
1977
1977
1977
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
Plant
Type***
ASEA
ODEA
TF/CS
AS
AS
TF
ASEA
ASEA
ODEA
ASEA
ABF
ASEA
AS
ASCS
AS
TF
TF
TF
TF
AS
ODEA
RBC
TF
ASEA
AS
ASEA
ASEA
ASEA
ASEA
ASEA
ABF
ASCS
ODEA
AS
ASCS
AS(2)
AS
TF
TF
AS
AS
AS
AS
ASCS/TF
ODAS
ASEA
AS
RBC
TF
ASCS
: Secondary Treatment Standards
Actual Flow '
cu in/day
1,628
155
30,660
1,892
3,785
6,434
132
26
2,233
45
18,550
568
20,820
568
5,185
833
20,820
20,060
6,056
11,880
795
1,438
492
189
1,287
643
795
170
416
1,136
1,855
643
757
2,650
492
2,687
20,440
303
4,164
1,136
21,950
908
946
314
3,179
1,817
11,910
8,327
4,542
3,179
mgd
0.43
0.041
8,1
0.5
1.0
1.7
0.035
0.007
0.59
0.012
4.9
0.15
5.5
0.15
1.37
0.22
5.5
5.3
1.6
3.14
0.21
0.38
0.13
0.05
0.34
0.17
0.21
0.045
0.11
0.30
0.49
0.17
0.20
0.7
0.13
0.71
5.4
0.08
1.10
0.30
5.8
0.24
0.25
0.083
0.84
0.48
3.12
2.2
2.1
0.84
% Design
54
59
68
'V
50
f7
54
28
66
80
69
30
55
60
?8
50
68
98
87
70
51
60
33
80
89
96
75
60
68
52
4?
34
59
4?
87
76
98
114
101
86
64
78
60
69
86
48
57
44
48
f
Met Not Met Not Met
(Operation) (Design & Operation)
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
. X
X
X
X .
X
X
X
X
x
X
X
X
X
*Standards not met primarily because of operations oriented problems which would not
require major capital expenditures to, correct.
**Standardg not met because of facility! limitations that would require a major designed
plant expansion to correct. I
***ASEA - Activated Sludge Extended Aeration; ODEA = Oxidation Ditch
extended Aeration; TF - Trickling Filjter; CS - Contact Stabilization- AS =
Activated Sludge; ABF = Activated Biotilter; RBC = Rotating Biological
Contactor.
t
26
-------
Operations Costs
An evaluation was made of the operational costs for wastewater treatment.
Cost information for individual facilities is shown in Appendix G. The
average for each cost category is shown in Figure 4. All costs to the user
are included except general taxes which are paid to state and federal
governments and partially returned in the form of grants for construction.
These costs were not identifiable. Costs shown include capital investments
paid directly by the city or sanitation district, primarily bond debt
retirement. Two-fifths of the total costs was for capital improvements even
though most facilities surveyed had been built with partial grant funding.
These capital improvement costs were somewhat independent of facility type and
size and more dependent on administration policies, construction grant funding
opportunities, plant age, bond interest rates, etc. Capital improvement cost
therefore are not included in the following cost comparisons.
CAPITAL
IMPROVEMENTS
24.6e/1000gal
TRAINING & EDUCATION
0.13 *
SUPPLIES
3.9*
CHEMICALS
TRANSPORTATION O.44«
Figure 4. Average costs for wastewater -treatment in
fifty facilities surveyed.
A summary of cost information for various types and sizes of facilities
is shown in Table 5. Salaries accounted for the greater share of the costs
at facilities surveyed; training and education of staff members accounted for
the smallest portion. Costs varied so significantly from plant to,plant that
a general increase for inflation was not recognizable over the 2-1/2 year data
collection period.
Figure 5 illustrates the range and the overall 0 & M costs for different
types and sizes of facilities surveyed. The^average cost per unit of flow was
greater for smaller facilities than for larger facilities; the average 0 & M
cost for suspended growth facilities was more than for fixed film facilities.
However, fixed film facilities have historically had higher capital costs than
suspended growth facilities. In addition, of the ten facilities which could
not meet secondary treatment standards without major capital improvements nine
were fixed film facilities. Of the fixed film facilities, only trickling
27
-------
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-------
filters which were loaded conservatively were found to meet standards^consis-
tently. This suggests that even larger construction costs may be required for
fixed film facilities to meet standards with an acceptable degree of reliabil-
ity.
1BO
170
•MO
150
! 140
5
>-
i-
o no
o
°- »o
•-*
4*
§ SO
CO 70
g «o
§ so
4O
3O
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1O
HH AVERAGE
m
I RANGE
I
^^ ^ ^ V '
• I I M
w* ^^ K-iM J
% % v% ^
\
\
\
\\
i \
T
n
m
"/ %%
2, ^
0-0.1 0.1-10 to-to o-ai ai-tjo 10-10
FIXED FILM SUSPENDED GROWTH
Figure 5. Plant operations costs for major plant types and
selected flow ranges (
-------
TABLE 6. POWER USAGE FOB! 50 COMPREHENSIVE SURVEY FACILITIES
Plant
Ho.
002
007
012
013
014
015
019
020
021
022
024
026
027
028
029
032
034
035
036
038
039
040
041
047
048
050
051
052
053
055
060
061
062
063
065
066
068
069
070
074
075
077
080
082
085
086
092
093
095
097
Date
1975
1976 -
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1978
1976
1976
1977
1976
1976
1977
1977
1977
1977
1977
1977
1977
1977
1977
1977
1977
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
Plant
Type
ASEA
ODEA
TF/CS '
AS
AS
TF
ASEA
ASEA
ODEA
ASEA
ABF
ASEA
AS
ASCS
AS
TF
TF
TF
TF
AS
ODEA
RBC
TF
ASEA
AS
ASEA
ASEA
ASEA
ASEA
ASEA
ABF
ASCS
ODEA
AS
ASCS
AS(2)
AS
TF
TF
AS
AS
AS
AS
ASCS/TF
ODAS
ASEA
AS
RBC
TF
ASCS
Actual Flow
cu in/day mg'd Z Design
1,628
155
30,660
1,892
3,785
6,434
132
26
2,233
45
18,550
568
20,820
568
5,185
833
20,820
20,060
6,056
11,880
795
1,438
492
189
1,287
643
795
170
416
1,136
1,855
643
757
2,650
492
2,687
20,440
303
4,164
1,136
21,950
908
946
314
3,179
1,817
11,910
8,327
4,542
3,179
O.|43
0.041
8 11
OJ5
1.0
1.7
0.035
0.007
O.B9
0.012
4.9
o.ts
5.5
0.15
l.|37
0.22
5.5
5.3
l.fc
344
0.21
0.38
0.13
0.05
0.34
0.17
0.21
0.045
0.11
0.30
0.49
0.17
0.20
0.7
0.13
0.71 ,
5-4
0.08
i.io
0.30
5.8
0.24
0.25
0.083
0.84
0.48
3.i2
2.2
2.1
0.84
54
59
68
63
50
47
54
28
66
80
69
30
55
60
78
50
68
98
87
70
51
60
33
80
89
96
75
60
68
52
47
34
59
47
87
76
98
114
101
86
64
78
60
69
86
48
57
44
48
84
KWH/1000
gal*
3.0
3.2
0.83
2.7
2.4
1.0
4.3
_
0.87
_
0.43
1.3
2.1
2.7
0.40
_
0.52
0.61
1.3
2.3
0.72
1.1
3.1
4.3
2.7
2.6
7.1
4.2
2.3
5.8 ,
2.8
-
2.6
3.2
_
0.50
0.45
11.7
2.4
2.9
0'.97
3.3
1.1
3.2
_
0.81
1.0
1.3
•t/KWH
1.53
3.06
2.28
2.23
1.89
1.50
2.20
_
3.54
1.37
1.26
2.49
1.17
3.28
_
1.96
2.36
2.15
3.85
1.51
2. .87
3.24
2.56
3.58
2.64
3.40
2.96
3.31
2.35
3.68
2.00
3.44
_
6.13
2.45
2.73
2.71
3.75
2.00
4.20
2.09
2.44
2.00
3.47
3.71
-------
believed to be due to both inflation and the geographic location of plants
studied.
A more meaningful comparison of energy costs was made using kilowatt
hours per thousand gallons of wastewater treated. In this analysis the energy
usage was independent of survey dates or local unit energy costs and more de-
pendent on such things as plant loading relative to design or the type of aer-
ation used. Electrical energy consumption- varied from a low of 0.1 kwh/cu m
(0.4 kwh/1000 gal) in several fixed film facilities to a high of 3.1 kwh/cu m
(11.7 kwh/1000 gal) in a recently constructed plant using a modification of
the activated sludge process. Suspended growth facilities averaged 0.84 kwh/
cu m (3.2 kwh/1000 gal) treated and fixed film facilities averaged 0.22 kwh/cu
m (0.82 kwh/1000 gal) treated. The potential energy savings of many fixed
film facilities are reflected in these energy requirements. However, the
initial investment may be higher for these facilities because of the apparent
need for a more conservative design.
Staffing Considerations
In the Phase I research effort a considerable effort was made to corre-
late plants displaying good performance with a single or group of common para-
meters. Plant costs, operator certification, operator manpower, operator ap-
titude and aerator loadings were evaluated. The only correlation which
appeared to have significance was aerator loading. Aerator loadings are dis-
cussed in Section 8 as a topic of special consideration. Other evaluations
were expanded to include information from Phase II plants and are presented
here.
An analysis of staffing costs included only the personnel working direct-
ly with the plant. As such, city administrators, the town clerk, staff work-
ing on collection lines and other personnel indirectly involved with the fa-
cility were not included. Table 7 presents a summary of staff size and cost
for each of the fifty plants. The percentage of the plant salary cost to the
total operations cost is also shown. Capital improvement and bond debt re-
tirement costs were not considered part of the total operations budget and
were excluded from this analysis.
Table 7 shows three.selected units costs to present staffing information
on a common basis. Large differences existed in calculated unit costs. The
specific staff size ranged from 0.2 my/1000 cu m/day to 9.8 my/1000 cu m/day
(0.8 to 37 my/mgd). The adjusted staff salary cost ranged from $8,700/my to
$19,300/my. The specific staff cost ranged from 0.74 t/cu m to 26<|:/cu m
(2.84/1000 gal to 98^/1000 gal).
Staff size, staffing costs, and total operations cost were given special
consideration by graphically plotting the selected parmeter against plant flow
rates. Staff size versus plant flow rate is presented in Figure 6. Each data
point represents a plant surveyed. Those plants that met secondary standards
consistently are depicted with shaded dots; plants that did not meet standards
are depicted with open circles. Large variations in the number of staff per-
sons were observed for any given flow range. For example, for the seven
plants whose actual flow ranged from 760 cu m/day (0.2 mgd) to 1140 cu m/day
31
-------
TABLE 7.
STAFF SIZE AND COST FOR 50 COMPREHENSIVE SURVEY FACILITIES
Plant
No. Date
002
007
012
013
014
015
019
020
021
022
024
026
027
028
029
032
034
035
036
038
039
040
041
047
048
050
051
052
053
055
060
061
062
063
065
066
068
069
070
074
075
077
080
082
085
086
092
093
095
097
treated x
i
32
i
i
Budget
Unit Relationships
% of
Staffing Operations
s Costs Budget
28,685
3,540
189,970
34,164
50,000
30,312
5,191
2,500
17,878
3,600(est)
84,141
18,186
118,782
9,610
51,732
3,780
87,917
54,162
49,746
96,368
10,000
13,316
15,755
3,132
18,470
7,717
6,200
4,951
, 13,400
4,992
36,500
. 10,296
5,300
57,148
6,900
39,060
245,000
7,987
38,633
34,700
137,500
3,800
4,260
8,100
25,831
18,880
373,700
41,600
42,800
74,900
my/1000 cu m/day
0.264 - $/cu m
28
17
64
43
50
43
23
53
37
50(est)
40
57
43
42
47
30
50
52
59
65
25
55
57
60 «
45
30
46
40
65
19
45
31
38
66
61
33
67
81
64
43
41
23
60
53
56
46
54
44
52
66
Specific
Staff
Size*
7.0
7.3
1.5
6.0
5.0
1.8
17
37
2.5
25
1.5
11
1.4
5.9
2.9
1.6
1.3
0.8
1.5
2.2
4.8
3.4
12
6.0
5.6
3.4
2.9
11
6.6
.1.7
6.1
4.7
2.2
5.7
4.2
3.9
2.6
6.2
2.5
6.0
2.0
1.8
• 2.0
9.0
2.7
3.3
8.3
1.7
3.2
4.8
Adjusted
Salary**
9,500
11,800
15,800
11,400
10,000
10 , 100
8,700
9,600
11,900
12,000
11,500
11,400
15,800
10,900
12,900
10,800
12,600
12,900
13,100
13,800
10,000
10,200
10,500
10,400
9,700
13,500
10,300
9,900
18,500
10,000
12,200
12,900
12,200
14,300
12,500
14,000 •
17,500
16,000
14,000
19,300
11,700
8,800
8,700
10,800
11,200
11,400
14,400
11,200
11,300
18,700
Specific
Staff
Cost***
18
24
6.4
19
14
4.9
41
98
8.2
82
4.7
33
5.9
18
10
4.7
4.4
2.8
5.5
8.4
13
9.6
33
17
15
12
8.1
30
33
4.6
20
17
7.3
22
14
15
12
27
- 9.6
32
6*5
4.3
4.7
27
8.4
11
33
5.2
9.8
24
-------
(0.3 mgd), the total number of man-years used to operate the facilities varied
from 0.35 to 1.8. If a large staff size was a prerequisite for good perform-
ance, then a majority of shaded dots should be above the line of best fit.
This was not the case. A large staff does not necessarily promote good plant
performance.
• STANDARDS MET
O STANDARDS NOT MET
M3/DAY = MGD X 3785
.01 0.1 1.0 10
PLANT FLOW RATE - MGD
Figure 6. Correlation of total staff size with performance.
A similar evaluation was made to determine if higher salaries correlated
with good performance by attracting more highly qualified personnel. Figure 7
shows the relationship between staff salary and plant flow rate. Staff salary
includes base pay plus fringe benefits. Part time salaries were developed on
a basis of one man for one year. Salaries within a narrow range varied con-
siderably from plant to plant throughout the range of plant sizes studied. A
positive correlation between higher staff salaries and good plant performance
would be indicated by a significant fraction of the shaded does above the line
of best fit. Eight of the thirteen plants which met standards were operated
by personnel with below average salaries indicating no positive correlation
between high,er salaries and good performance. It was observed that persons
with more ability and potential were needed at many facilities. However,
securing a more qualified operator by offering a higher salary did not by
.itself appear to promote better performance.
Total plant operations costs were evaluated to determine if a positive
correlation existed with good performance. This data is presented in
Figure 8. Plants which met standards were dispersed throughout the, data
points. Facilities with high total operations budgets did not meet standards
with any more consistency than did facilities with lower budgets. Clearly,
improved treatment plant performance was not indicated by higher operating
budgets.
33
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20
PLANT JFLOW RATE-
Figure 7. Correlation of salaries with performance.
O STANDARDS NOT MET
M3/DAY= MGD X37B5
".01 0.1 1.0
PLANT FLOW RATE-MGD
10
Figure 8. Correlation of total operations costs with performance.
Operator Certification
j
The relationship between opera'tor certification and plant performance i
summarized in Table 8. "A" is the highest certification rating and "D" is th
lowest. In some states a Class I through Class IV rating system was used ar
an appropriate conversion to the "A1!1 through "D" system was necessary.
34
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TABLE 8. CORRELATION OF OPERATOR CERTIFICATION WITH PERFORMANCE
Certification Class
of Chief Operator
"A"
"B"
"C"
"D"
None
Number of
Facilities Surveyed
15
10
9
9
7
Secondary Treatment
Met Violated
6 9
4 6
1 8
1 8
1 6
Standards
% Met
40
40
11
11
14
In fifteen of the fifty facilities, the chief operator had an "A" certi-
fication. Six of those facilities met secondary treatment standards. Ten
facilities had "B" operators and four met secondary standards. Nine facili-
ties had "C" operators, nine had "D" and seven facilities were operated by
operators who were not certified at all. One plant in each of these categor-
ies met secondary standards.
Forty percent of the facilities which had "A" and "B" certified operators
were found to be meetng secondary effluent standards. This was a higher per-
centage than for other facilities, but significantly less than desired. It
was concluded that certification programs promote better plant performance,
but do not singularly qualify persons to produce a high percentage of
compliance.
SUMMARY
Identification of the causes of limited wastewater treatment plant per-
formance in fifty facilities showed that no facilities were limited by a
single factor. Each facility, even those meeting secondary treatment require-
ments were limited by several factors which affected the achievement of opti-
mum performance. In addition to multiple factors, each facility had a combi-
nation of problems which were unique to that facility. The evaluation of
specific items normally believed to be major problem/solution areas (i.e.
staffing, certification, operations budgets, operator salaries, etc.) did not
lead to positive correlations with good performance. The ranking and evalua-
tion of the most critical performance-limiting factors for all plants did not
provide a clear approach to improving the performance of existing facilities.
However, the high ranking of improper technical guidance provided by design
engineers, equipment suppliers, regulatory agency personnel and other operator
trainers, along with the high ranking of many process control oriented design
.features, indicates the problem stems from a much broader base than with just
local plant administrators and operators. The findings clearly indicate the
need for an alternative to the conventional efforts for improving biological
wastewater treatment plant performance.
35
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SECTION 6
THE UNIFIED CONCEPT
To better describe the plant performance problem a "Unified Concept for
Achieving Optimum Plant Performance" was presented in the Phase I report (5).
The concept was used to describe the interrelationships among the factors
limiting performance and the programs implemented to address these factors.
From the understanding provided by[the concept, a recommended approach (i.e.
Composite Correction Program) for addressing a specific facility's perform-
ance problem was developed. The Unified Concept will be used in this report
to explain the differences in the problem areas that existed in site-visit
plants versus the comprehensive evaluation plants. A discussion regarding
implementation of the Composite Correction Program is also presented.
i
The Unified Concept for Achieving Optimum Plant Performance is illus-
trated in Figure 9. As shown, the goal is to obtain optimum performance from
a given treatment plant. The horizontal line represents a given plant's posi-
tion with respect to optimum performance. Factors limiting performance tend
to move the plant further away from
the goal. The number of performance
limiting factors is indicated by the
number of arrows pointing downward.
The relative severity of the various
problems is indicated by the length
of the downward arrows. A large
number of factors and/or a few severe
factors would cause a facility to be
far removed from optimum performance.
Finally, the length of the horizontal
line represents the degree of less
than optimum performance.
GOAL
OPTIMUM PERFORMANCE
PLANT
POSITION 2
The elimination of factors
through use of a correction program
would tend to move a plant's position
closer toward optimum performance as
indicated by the arrows pointing up-
ward. The term correction program is
used to describe any public or pri-
vate activity; national, regional or
local in scope that eliminates the
effects of adverse factors. The
length and number of upward arrows
indicates the number and relative
PLANT
\POSITION 1
FACTORS LIMITING PERFORMANCE
•ADMINISTRATION
•MAINTENANCE
•OPERATION
•DESIGN
Figure 9. The unified concept for
achieving optimum plant performance.
36
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influence of correction programs applied to a given treatment facility. Cor-
rection programs are many and varied, probab|y because the performance limit-
ing factors are so diverse. As factors limiting performance are corrected,
the plant's position moves closer toward optimum performance and the length of
the horizontal line becomes shorter, indicating a better performance level.
To achieve the desired performance goal, all of the factors limiting
performance must be addressed.
INDIVIDUAL CORRECTION PROGRAMS
A popular approach to improving plant performance has been to develop
programs with the purpose of addressing performance-limiting factors or groups
of factors at a large number of facilities. Three example programs of this
type are the construction grants program, the NPDES permit enforcement pro-
gram, and the operator training program. The construction grants program
focuses on the construction of new or upgrading of existing facilities, and
thereby addresses factors such as hydraulic overload and inadequate clarifica-
tion capacity. The NPDES permit program focuses on the effluent quality of
all municipal facilities and potentially could use the associated enforcement
capability to motivate administrative personnel. Operator training programs
focus on plant operators and address factors like sewage treatment understand-
ing. In like manner, other programs focus on specific factors or groups of
factors limit-ing performance at many treatment facilities. Because of this
emphasis these programs have been labelled Individual Correction Programs to
point out the emphasis on individual factors the programs are intended to
address.
Since PL 92-500 was enacted in 1972 the major emphasis has been to
improve treatment plant performance through Individual Correction Programs.
The results have been partially successful in that some new or upgraded facil-
ities are performing at a satisfactory level. However, most facilitites are
not performing well (1,2,5). One of the reasons for only moderate success of
these programs is the manner in which they have been implemented. Most pro-
grams were established to concentrate on specific areas of need representing a
common problem at a large number of treatment facilities. However, every fac-
tor that limits performance at a specific facility must be eliminated before
that facility wil achieve optimum performance. Individual Correction Programs
cannot address the unique combination of performance limiting factors at an
individual plant.
The role of Individual Correction Program in the Unified Concept theory
is demonstrated using an example. Consider a facility with two major and
other minor factors limiting performance. Assume the major factors are
hydraulic overload due to a large volume of inflow, and improper operator
application of concepts and testing to process control. With these two major
factors limiting performance the plant could be far removed from optimum
performance at Plant Position 1 as shown in Figure 9. Using a construction
grant (individual Correction Program), a holding pond could be constructed to
equalize peak storm flows and thus address the hydraulic overload problem.
However, the construction grant and associated activities may not address the
operator application of concepts and testing to process control factor. This
37
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factor then becomes prominent in the facility's ability to achieve desired
performance. This example facility would then be at Plant Position 2 as shown
in Figure 9.
This example illustrates whyjmany upgraded facilities have not achieved
desired performance. Individual Correction Programs do not eliminate all the
factors limiting performance at a
imply that Individual Correction
particular facility. This is not meant to
Programs should be abandoned. There is a
continued need for these programs because of the multitude of performance
limiting factors that exist. It should be recognized, however, that programs
of this type are limited in their ability directly to achieve optimum perform-
.ance at an individual plant.
COMPOSITE CORRECTION PROGRAM
GOAL
OPTIMUM PERFORMANCE
An approach called a Composite Correction Program (CCP) was developed
during the Phase I effort. The objective of this approach was to identify and
eliminate all the factors which limit performance at a specified plant. This
qpproach is illustrated in Figure 10. As shown, all factors at an individual
plant are systematically identified and eliminated and the plant achieves the
goal of optimum performance (Position 2) .
A CCP can only be completed when desired changes are implemented to
achieve optimum performance at a [particular facility. Therefore,it can be
concluded that an overall improvement in effluent quality must occur if
CCP's are properly implemented on a
broad scale. Broad scale implementa-
tion of CCP's is limited by the avkil-
ability of qualified personnel[ to
direct such programs. This conclusion
is supported by the high ranking; of
the improper technical guidance factor
which was discussed earlier. I
I
[
The achievement of improved per-
formance through the CCP approach I may
lag significantly behind the elimina-
tion of performance-limiting factors.
For example, in a facility in which
fifteen factors are identified, eight
or ten may have to be eliminated
fore a measureable improvement in
PLANT
POSITION 2
be-
ef-
fluent quality is achieved. If only
six factors are eliminated and no fur-
ther work is pursued, the effort could
be judged fruitless even though each
individual effort to eliminate a prob-.
lem may have been exactly correct.
Because incremental improvement in ef-
fluent quality does not typically oc-
cur with the elimination of each fac-
tor, the plant administrative staff may
COMPOSITE CORRECTIO
PROGRAM,
/ I . t
PLANT
POSITION 1
FACTORS LIMITING PERFORMANCE
•ADMINISTRATION
•MAINTENANCE
•OPERATION
•DESIGN
Figure 10. The role of the com-
posite correction program (CCP)
in the unified concept.
38
-------
misinterpret or falsely judge the value of the accomplishments and prematurely
stop the program. A similar situation exists in assessing the value of Indi-
vidual Correction Programs and accounts for some of the confusion concerning
the value of these programs.
The lack of incremental improvement in effluent quality may make it dif-
ficult for plant administrators to distinguish between the misdirected efforts
of unqualified personnel and the appropriate efforts of qualified personnel.
When improvement in performance does not occur, unqualified technical person-
nel may falsely claim that desired performance cannot be achieved unless other
factors are addressed. Many administrative personnel are not in a position to
evaluate the technical merit of the recommendations made. However, CCP imple-
mentation should be able to overcome this difficulty because the objective is
to provide a desired plant performance level in the most economical manner.
Both the performance and cost aspect of this objective can be measured, there-
fore providing a straightforward endpoint that can be evaluated. If measure-
able progress is not achieved, the plant administration should not abandon the
concept of the CCP approach, but should consider continuing the program with
other persons. In so doing, the improper technical guidance factor noted dur-
ing this research can be eliminated since only successful personnel will be
able to continue in business.
UNIFIED CONCEPT - SITE VISIT VERSUS COMPREHENSIVE EVALUATIONS
During plant selection, facilities that were totally inoperable, exces-
sively overloaded and/or inadequately staffed, were excluded from further
study. Performance limiting factors were identified at facilities in which a
site visit only (1/2 day visit) was made and facilities for which a comprehen-
sive evaluation (4-7 days) was completed. The results from these plant visits
were different as discussed in Section 5 of this report. In general, the site
visit plants had more design and maintenance problems and the comprehensive
evaluation plants had more operational problems. Two reasons are given for the
difference in these results. Many site visit plants which had- design and/or
maintenance problems were excluded from a comprehensive evaluation, thus per-
formance—limiting factors for site visit facilities were more heavily weighted
toward these problems. Secondly, the site visit plants were not extensively
evaluated and only the more obvious problems were observed. The more obvious
problems were typically design and maintenance oriented.
The site visit facility problems were de-emphasized relative to the dis-
cussion of performance-limiting factors for plants in which a comprehensive
evaluation was completed. Yet, the major design, maintenance and other severe
problems that existed at the site visit facilities are important. However,
these problems reflect a different level or magnitude of factors limiting
performance. To describe these different levels of problems a modification of
the Unified Concept was developed as shown in Figure 11.
Major performance-limiting factors contribute to a facility that is con-
sidered inoperable as depicted Figure 11. Many of the site visit plants which
were excluded from further research were at the position 1 level with major
I/I problems, extensive overload problems, staffing problems and or equipment
inoperability problems. These types of factors had been corrected at the
39
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comprehensive evaluation facilities. The plants where comprehensive evalua-
tions were conducted were considerejd to be operable facilities and located at
position 2 in Figure 11. The application of better process control (opera--
tion) procedures would have allowed| these plants to achieve the goal indicat-
ed, which is a good quality, economically produced effluent. Indeed, major
design, maintenance and other severe problems must be addressed to obtain an
operable plant. Then, as plants achieve "operable" status the problems docu-
mented by this research will becomejmore paramount in the plant's inability to
achieve a desired level of performance. In this manner the Unified Concept
can be used to describe the relative position, with respect to optimum per-
formance, of the problems documented for the site visit facilities and the
comprehensive evaluation plants described in this report.
L'
GOOD, ECONOMICAL
EFFLUENT
OPERATION
IPROCESS CONTROL)
I
CAPABLE PLANT
ADMINISTRATION I [DESIGN! |MAINTENANCE|\
Figure 11. A relationship of major types of performance-limiting factors.
i
IMPLEMENTATION OF A COMPOSITE CORRECTION PROGRAM
The approach that should be ta'ken for implementing a CCP is best illus-
trated in Figure 11. As shown, the step between an operable facility and a
good economical plant effluent (optimum performance) is plant operation (i.e.
process control). It is from the process control position that a determina-
tion must be made as to whether 'the plant performance problem is due to
improper operations or due to an inoperable plant. If the problem is opera-
tions, process control is improvedjand desired performance is achieved. If
the problem is with an inoperable plant, then recommendations for corrective
action must be provided and implemented.
An example approach to implementing a CCP will be discussed. Initially,
a plant is assumed to be operable and process control procedures are initiated
to attempt to improve performance. If problems arise in the design,
40
-------
maintenance and/or administration areas, an effect on process control occurs
and recommendations to eliminate the effect are implemented. Assume that the
CCP reaches an impasse in terms of improving performance because the plant is
found to be organically overloaded. In this case the plant is not operable
because as it exists it cannot properly treat the wastewater. Conduct of the
CCP would require completion of construction -to allow the plant to become
operable. After construction CCP activities could continue until the desired
performance level was achieved. The important aspects from this example are
that the CCP was continued until the performance objective was reached, and an
Individual Correction Program (i.e. plant construction) was not abandoned but
effectively utilized. To accomplish the steps outlined in this example the
CCP implementor must not only have expertise in plant operation, but also must
be knowledgeable in design, administration and maintenace aspects of plant
performance.
During Phase I (4,5) it was established that CCP's must be implemented
over a long period of time to: determine if the problem is with operations
or with an inoperable facility; be compatible with the time required for bio-
logical system response (i.e. months); and transfer the ability to maintain a
desired performance level to the plant staff.
From an independent contractor basis, the long time frame can best be utilized
by periods of on-site involvement where the consultant assumes the responsi-
bility for major aspects of process control and periods of off-site non-
,involvement when the plant staff must re-assume this role. This approach is
graphically illustrated in Figure 12.
INITIAL SITE
VISIT
TELEPHONE
CONSULTATION
ON-SITE
CONSULTATION
LONG TIME INVOLVEMENT
Figure 12. Implementation of a CCP.
During the initial consultation period, the consultant becomes well-
aquainted with facilities, personnel, operations procedures and other items
that influence process control. A common testing procedure is established to
serve as a basis for communication to recommend and implement changes in plant
operations. Apparent factors limiting performance are identified and appro-
priate corrective actions are recommended and implemented. Plant specific
operator training is initiated by explaining process control strategies and
requirements. Finally, a basis is established to implement on-going consulta-
tion activities.
The on-going consultation activities spans the long time involvement
required. Periodic site visits are completed to verify benefits of changes
41
-------
made, establish priorities for other possible changes, enhance operator train-
ing, and identify and implement corrective action to solve other plant per-
formance limiting factors that tybically evolve. Additionally, telephone
consultation is used so that the consultant can stay abreast of plant opera-
tion status, recommend process control modifications, identify optimum times
for site visits, and provide guidance so that as more and more of the process
control responsibility can be transferred to plant personnel.
Reporting is used to provide; sketches for minor plant modifications,
provide data for budget and staffing plans, provide information for regulatory
agencies and describe project status. A final report is prepared to describe
the plant status, document project results and define plant capabilities. It
is not intended that reporting be
intended to be completed as the CCP
used to recommend actions. Actions are
progresses.
Benefits of a properly implemented CCP include: technical consultant
accountablity since action on recommendations are part of the CCP; long-time
involvement is achieved yet the client costs are minimized because the tech-
nical consultant is not working at [the facility 100 percent of the time, yet
is involved and accountable 100 percent of the time; operator training is en-
hanced because it is directed to the achievement of better process control and
performance at the operator's plant; process control capability is transferred
to plant personnel; slow biologicaljsystem response is addressed through long-
time involvement; the program is action oriented not report oriented and the
objective of good performance is established and pursued until it is achieved.
During both Phases of the research effort, six CCP's were implemented.
However, the primary objective of the research effort was to document perform-
ance-limiting factors and not the conduct of CCP's. As such, a modified level
of effort was expended in the conduct of the CCP's. The results obtained from
the CCP's that were implemented are discussed in the next section of this
report.
42
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SECTION 7
COMPOSITE CORRECTION PROGRAM DEMONSTRATIONS
The CCP approach was demonstrated and documented at Plants 029 and 050
during Phase I (4,5), The resources necessary to achieve successful CCP
demonstrations during Phase II were limited due to budget constraints and the
original research objectives. However, because of the potential applicability,
of the CCP approach on a national basis, further demonstrations were felt to
be necessary. Therefore, five wastewater treatment plants were selected to
demonstrate the CCP approach when implemented at a level of effort compatible
with the EPA research contract.
The comprehensive evaluations involved in-plant operations assistance
similar to that requied in a typical CCP. Therefore, when surveys were initi-
ated, most plants were considered to be potential candidates for demonstra-
tions. The potential of each plant was evaluated based on the nature of the
performance-limiting problems determined. The resources available for imple-
menting CCPs were limited to the initial one-week on-si,te involvement and to
follow-up telephone consultation and data analysis assistance. In one case, a
half-day return visit was possible because of other work in the same vicinity.
This level of effort is typically substantially less than required to satis-
factorily implement the CCP approach. As such, plants selected usually had
adequate staffing and basically operable facilities. Another important cri-
teria was the plant administrator's and staff's willingness to work with, the
research personnel. This support was necessary because in several facilities
increases in manpower and minor design modifications were required to show
improved performance. In one of the plants where improved performance was
achieved, this effluent quality was not expected to continue for an indefinite
length of time because of inadequate sludge handling capacity. Many facili-
ties evaluated were not selected even though a large potential for improvement
was identified. At these facilities a CCP was applicalbe but more time and
effort than was available would have been required to gain the confidence and
support of the plant'personnel and administrators.
In the remainder of this section, the results of the five CCP demonstra-
tions that were implemented during Phase II are presented. Also, a discussion
is included on the potential for improved performance at all fifty facilities..
CCP.AT PLANT 086
Plant 086 is a newly constructed, extended aeration activated sludge
facility designed for an average flow of 3785 cu m/day (1.0 mgd). Actual flow
recieved during the last eight months of 1978 was 1700 cu m/day (0.46 mgd).
Wastewater is mostly domestic in nature with some light industrial and
43
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commercial wastes. On occasions, storm water inflow substantially increases
wastewater flow to several times the daily average. This problem was address-
ed in design by preserving an existing lagoon for excess storm water treat-
ment. At the time of the evaluation and follow-up work, the plant was receiv-
ing about three-fourths the design organic loading. Only one of two aeration
basins was in operation and aeration basin loading was approximately 224
gm/day/cu m (14 lb/day/1000 ft3). Both clarifiers were loaded at about 8 cu
m/day/sq m (190 gal/day/sq ft).
Prior to the comprehensive survey, effluent quality periodically violated
permit requirements. The reason for poor effluent quality was limited sludge
wasting which resulted in poor sludge character and periodic, excessive solids
loss from the final clarifiers. The superintendent had requested help from
the city engineer and from the state regulatory agency in establishing a
sludge wasting program. The superintendent had been referred to technical
publications which he felt were of ijittle help. Additionally, the superinten-
dent had quit attending training cqurses because he could not get help with
the problems at his facility.
Plant 086 was chosen for a CCP demonstration because the operator was
very supportive, the city administrators were actively interested, and design
limitations of the facility were no|t critical at current loadings. Finally,
it was anticipated that significantly improved plant performance could be
demonstrated.
CCP Implementation
The CCP was initiated in conjunc-
tion with the in-plant comprehensive
evaluation. The superintendent's pre-
vious concern for establishing ; a
sludge wasting program coincided vejry
closely with the,process needs of the
plant. Process control equipment,
testing procedures and calculations
were demonstrated as an integral part
of the initial activities. By the ejad
of the week the plant staff were wasp-
ing a desired mass of sludge. Survey
recommendations were used to inform
the plant administrators of the accom-
plishments of the week and to obtajln
support for purchasing equipment need-
ed to continue the process control
program. The results of process con-
trol tests were sent to the contractor
on a weekly basis on a sheet that was
provided (Figure 13.) Assistance in
making process control decisions wks
provided by telephone for a 10-month
period following the initial survey.
PHOCESS ctsmtni, TESTS
CENTRIFUGE TEST
ATC il. f
IZ -,
l.f- .
IO.G
70%
?'^ ..
.
.//?
aETUwi SLCDCE FLOW PERCENTAGE
77*» f??* S3& »•
SLUDGE BLANKET TEST
MB T.r 4.f 4.IS" T.M"'
SLUDGE IHVT21TOKT
AS° i.ac* 3..i
-------
Site visits which are normally a part of a CCP were not possible within the
scope of the research effort.
Factors Limiting Performance
The obvious factor limiting performance of Plant 086 was the inability to
apply concepts of process control. This limitation was addressed by imple-
menting a process control program. Through documentation developed during the
survey week and by explaining how testing fit into the process control pro-
gram, the mayor, city administrator, and a councilman agree to provide the
needed testing equipment. With proper testing equipment and guidance in mak-
ing process control decisions, activated sludge mass control was no longer a
significant problem* The factors that limited performance included: improper
operator application of concepts and testing to process control, improper
technical guidance andinadequate process control testing.Each of these
factors was addressed.
As process control was implemented design related problems became appar-
ent . Among these were inadequte process controiability and inadequate sludge
wasting capability. Process contollability was limited by return sludge flow
rate control.No" return sludge flow measurement was provided, and control
adjustments in the desired range resulted in unacceptable variations and plug-
ging. It was determined that a constant, higher^return sludge flow rate would
be acceptable, although not optimum. If site visits had been possible, the
advantages of closer return sludge flow control could have been evaluated fur-
ther and techniques for improving adjustments of return sludge flow may have
been successfully applied to the problem.
Inadequate sludge wasting capability was a another design related .factor
identified during the survey. No waste sludge flow measurement was provided
with the plant and the waste sludge flow rate had to be estimated using the
drawndown rate in a final clarifier. Although not convenient, this method
worked adequately for present plant loadings. A greater problem contributing
to inadequate sludge wasting capability was the limited size of the sludge
lagoons. These were the only sludge handling facilities provided. Design
documents made no mention of additional ultimate sludge disposal methods.
i Following the initial evlauation good effluent quality was maintained.
Very good documentation of sludge wasting requirements was. also developed
indicating that an average of 251 kg (553 Ib) of sludge was wasted per day
(approximately 7400 gpd). Since no method of removing supernatant or sludge
from the lagoons had been provided, it was estimated that this wasting rate
would completely fill both lagoons in less than a year. To avoid a serious
sludge handling problem, the superintendent, with the help of research person-
nel, convinced the city administrators of the need to obtain a sludge truck so
sludge could be removed from the lagoons on a periodic basis. The state
agreed to reopen the city's contruction grant and provide the needed truck.
Thus, a major performance-limiting, design-oriented factor was eliminated.
Other problems may limit sludge wasting capability, such as inadequate man-
power to operate the truck, production of odors from the sludge storage
lagoons or inadequate land available for ultimate sludge disposal. If these
45
-------
problems occur they must also be identified and corrected if good performance
is expected to continue.
Other factors which were determined to limit plant performance to a
lesser extent were inhibitory industrial wastes and infiltration/inflow. Slug
loads of inhibitory wastes had been received periodically and had degraded
effluent quality. The superintendent had isolated the probable source and was
waiting to obtain a sample for identification and verification of the source
of the problem. .
Infiltration/inflow continues to be a minor problem on a periodic basis.
The I/I problem requires that faster settling sludge which is more easily con-
tained and controlled during high I/I flows be maintained in late winter in
preparation for spring rains and r)mnoff. Daily flows as high as 9800 cu m
(2.6 mg) have been treated successfully in the plant by maintaining faster
settling sludge. The sacrifice is a 5 to 10 mg/1 increase in effluent TSS and
BODj on a continuous basis while the faster settling sludge is maintained.
This slight degradation will be necessary every year during high potential I/I
flow periods, and will be a continuing factor limiting plant performance.
Performance
Performance of Plant 086 improved dramatically. Plant 086's recorded
effluent results for the time prior to the CCP did not reflect excessive
solids loss that was known to occur. Therefore, actual effluent quality was
estimated. Recorded and estimated! effluent TSS and %OD$ concentrations are
presented in Figure 14. The amount'of
TSS lost due to the uncontrolled mass
prior to the CCP was estimated :by
determining the amount of activated
sludge wasted after good process con-
trol and associated sludge wasting had
been implemented. This value was com-
pared with the amount of sludge was tied
previously. Typically the amount of
BODcj lost during excessive solids
loss is less than the amount of TSS
lost. During comprehensive surveys [at
five plants, separate samples were
collected during observed solids-lo|ss
periods, and these samples were ana-
lyzed for BOD^ and TSS concentra-
tions. The average 6005 t0 TSS
ratio for these samples was 0.5. Thiis
ratio was used to estimated the aver-
age BODg concentration prior to tlhe
CCP. Estimated effluent BOD5 and
TSS concentrations before initiation
of the CCP were 90 mg/1 and 150 mg/il,
respectively. For the remaining eight
months of 1978, excessive solids loss
did not occur and recorded results are
170
150
130
120
O 90
o
_
111 so
EST. ACTUAL
EFFLUENT TSS
EST. ACTUAL
EFFLUENT BOO,
-CCP INITIATED
PERMIT STANDARD
1978
Figure 14. Effluent BOD5 and
TSS at Plant 086.
46
-------
believed to accurately reflect effluent quality.
averaged 7.8 mg/1, and TSS averaged 3.9 tng/1.
During this period, BOD5
Discussion
The CCP demonstration at Plant 086 was highly successful because of .the
nature of the most important performance-limiting problems and because of en-
thusiastic involvement of city personnel throughout the project. Although
paid below average, the plant superintendent possessed above average aptitude.
Atributes which were of particular value were his ability to learn to imple-
ment process control concepts and his ability to work with and solicit support
from the city administration. When a superintendent involved with a CCP does
not excell in these qualities, site visits are necessary for both training of
in-plant personnel and for increasing administrators' familiarity with plant
needs.
CCP AT PLANT 065
Plant 065 is a contact stabilization activated sludge plant with aerobic
sludge digestion, and ultimate sludge disposal by land application. Design
flow is 568 cu m/day (0.15 mgd), and wastewater flow during 1978 averaged 454
cu m/day (0.12 mgd), or 80 percent of design. The plant received primarily
domestic wastes; however, several slugs of inhibitory petroleum wastes were
received during the year. Wastewater strength in 1978 averaged 208 mg/1 and
190 mg/1 for BOD5 and TSS respectively resulting in an organic loading on
the aeration basin (contact and reaeration) of 464 mg/day/cu m (29 lb/day/1000
ft^). The *final clarifier is operating at a surface settling rate of 21 cu
m/day/sq m (512 gal/day/sq ft).
CCP Implementation
The comprehensive survey provided time to initiate CCP activities at
Plant 065. Plant 065 was basically an operable facility in that all required
processes were provided in the plant design, and all necessary equipment was
operable. The operator expressed a sincere desire to improve his operation
and made signifiant improvements during the survey week. Initial efforts were
directed at operator training in process control. Nearly all necessary test-
ing equipment was available at the plant. Equipment which was not initially
available, was obtained during or shortly after the initial survey.* Process
control testing, calculations and trend graphs were initiated on a daily
basis.
As a portion of the CCP activities process control results were sent to
research personnel on a bi-weekly basis. Telephone consultation was used
extensively over a one-year period. Additionally, a half-day .site visit was
possible because of other related work in the area.
Most of the effort within the CCP was directed at improving the opera-
tor's ability to apply the basic concepts of plant operation and process con-
trol. The operator had been performing nearly all necesary testing and opera-
tions tasks prior to the initiation of ;CCP activities. However, test results
were not used properly to make process control decisions. A new process
47
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control program was established to paintain the total sludge inventory at pre-
selected levels chosen to produce desired sludge characteristics.
Additionally, the operator was taught how to adjust the return sludge flow
rate to obtain optimum distribution' of sludge.
i
Factors Limiting Performance
The most important performarice-limiting factor was improper operator
application of concepts and testing to process control. Neither return acti-
vated sludge flow control nor activated sludge mass control had been applied
correctly at the plant. The return rate had been maintained at a high level
(over 150 percent), which contributed to excessive solids loss over the clari-
fier weirs as well as poor sludge distribution within the plant. Sludge mass
control was completely inadequate in that only a small fraction of the sludge
produced was intentionally wasted to the aerobic digester. The remainder was
discharged in the plant effluent diiring peak flows of the day. In addition,
partially digested sludge was frequently returned to the reaeration basin via
the digester supernating mechanism.,
I
The problem of improper operator application of concepts was compounded
through improper technical guidance from the state district engineer and the
town's consulting engineer. The state engineer had recommended that specific
MLSS values be maintained in the Contact and reaeration basins because "it
looked like the best treatment achieved in the past had occurred at those
values." Because of the long time\associated with changing sludge character-
istics, such cause and effect assumptions are almost always incorrect. The
town's consulting engineer was preparing a facilities plan before and during
the period that the CCP activities [were implemented. A requirement for grant
funding is to consider optimizing operation of existing facilities. Yet, very
little was being done in the plant to meet this requirement.
Initiation of the new process fcontrol program resulted in the identifica-
tion of several secondary factorsjlimiting plant performance. The aerobic
digester was shown to be too small [to provide adequate stabilization and vol-
ume reduction of sludge prior to land application. Also, available land for
sludge application was inaccessible for long periods due to inclement weather
or crop conditions. Finally, the plant operator was expected to help with
other city utilities which did not allow the time required for sludge disposal
tasks. Typically, when secondary1 factors such as these begin limiting a
plant's perfromance, a site visit is conducted to explain the situation and
alternatives to plant administrators. This was not possible and the operator
was forced to work alone with plant administrators that had been convinced
that they needed a new plant. Consequently, their general attitude was to do
as little as necessary with the existing facilities. After several months of
discussion, the operator succeeded! in getting approval to haul sludge to a
more distant site owned by the town. Prior to this approval, some relief
occurred in the sludge handling situation from a modification that was made in
the source of waste sludge. A minor modification allowing wasting from the
return sludge line resulted in a desired mass of sludge being wasted with less
volume. I
48
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Another secondary performance limiting factor was uncovered when optimum
distribution of sludge was attempted within the system. It was discovered
that the steel wall between the contact and reaeration basins was designed to
be movable and that it allowed significant leakage to occur between the two
basins. As a result, the return sludge concentration was substantially higher
than the reaeration basin concentration due to back mixing of the mixed liquor
from the contact basin area into the reaeration basin. The result was inade-
quate sludge distribution control and a plant which was operating somewhere
between the contact stabilization and conventional activated sludge modes. As
such, a loading condition existed which was not characteristic of either
process mode. Modifications to seal the wall or provide piping for operation
as conventional activated sludge could have improved controllability of the
plant at very little cost; however, because of the attitude of the
administration, no steps were taken to improve this situation.
Slug discharges of a petroleum product were received at the plant period-
ically throughout the last several months of the CCP. A deterioration of
effluent quality at this time was believed to be caused by the repeated oil
discharges. The operator had found the probable source by the end of the CCP
and intended to work with those responsible to eliminate the problem.
Performance
As a result of the CCP, substantially improved performance resulted.
However, several factors continued to limit plant- performance and prevented
standards from being met consistently. Quantitative measure of improved
performance could not be determined since prior to the CUP, samples were not
collected during periods of excessive solids loss. Estimates of effluent TSS
and BODc quality were made based on actual sludge production documented
during the CCP and estimates of previous wasting. This approach was similar
to that outlined at Plant 086.
estimated to be 70 mg/1 and 140 mg/1, respectively.
progress, effluent
Discussion
Effluent BOD5 and TSS before the CCP were
While the CCP was in
averaged 29 mg/1 and effluent TSS averaged 15 mg/1.
The major objectives of the CCP were to optimize plant performance and to
transfer the capability to the operator to maintain this performance. Signif-
icant improvement in performance and the operator's process understanding and
control capabilities were achieved. However, sludge character was never com-
pletely controlled at an optimum. The unavailability of resources to conduct
required site visits contributed to this partial success. Normally site
visits are made when observations or results do not follow the expected pat-
tern. Additionally, the lack of support of the plant administrators encourag-
ed by the apparent need of a new facility hindered the success of this CCP.
CCP AT PLANT 074
Plant 074 is a newly constructed activated sludge plant. Effluent fro'm the
plant is discharged to two aerated lagoons, a non-aerated polishing pond and a
chlorine contact basin. The plant was designed for an average flow of
1320 cu m/day (0.35 mgd) , and a peak hydraulic flow of 5700 cu m/day
49
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(1.5 mgd) . The facility is designed such that wastewater volume in excess of
the activated sludge plant's capabilities can be automatically directed to the
aerated lagoons. Waste sludge from the activated sludge plant is discharged
to the aerated lagoons. Plant 074 [receives wastewater from a single, signifi-
cant industrial waste producer, a cannery. The plant is operated by a plant
superintendent, an operator, and a third city employee who checks the plant on
some weekends. The plant superintendent has the highest grade certification
in the state, is active in the state pollution control association and attends
short courses and operator schools.
CCP Implementation
During the comprehensive survpy, alternative process control tests and
calculations were demonstrated. By the end of the survey plant personnel
decided to implement the test procedures, calculations and data evaluation
methods. Thus a good basis was developed for communication between research
and plant personnel. A weekly operations report was prepared as a method of
maintaining communication. Process, control decisions were discussed by tele-
phone. This type of assistance was; provided for a 7-month period.
Factors Limiting Performance
f
Several design and operations oriented factors significantly limited the
performance of Plant 074. The design oriented problems were quite critical
and could not be addressed within the scope of the CCP, however, it was
believed that the potential for'improved performance could be demonstrated by
addressing the operations oriented [factors.
i
The most obvious operations ! oriented problem was improper operator
application of concepts and testing to process control. At the time of the
survey, the operator was trying to build the MLSS concentration to a previous-
ly obtained level of about 7000 mg/1 - 8000 mg/1. However, the MLSS could not
be raised above about 2500 mg/1 due to solids loss over the final clarifier
weirs. Intentional wasting had been discontinued, and the return sludge flow
rate had been increased in attempts to build the MLSS concentration. This
strategy failed, and the entire sludge mass was "dumped" to eliminate the
filamentous organisms that were thought to be dominant in the system. The
sludge mass had been rebuilt to the 2500 mg/1 level when the survey was initi-
ated. The superintendent had planned to dump the sludge mass a second time
and disinfect the entire system. However, during the initial survey several
changes were made and the operator was convinced to look at other alterna-
tives. The major changes were: implementing a more complete sludge monitor-
ing program; reducing the return sludge flow rate; wasting daily to control
the sludge inventory and sludge masis was increased more slowly to allow sludge
character to develop with the changing sludge inventory.
A design oriented problem was the method of ultimate sludge disposal.
The plant was designed so that the! final effluent passes through two aerated
lagoons. Additionally, sludge wasted from the activated sludge plant was
designed to be discharged from the [return sludge line to the aerated lagoons.
Disposing of sludge in this manner will eventually degrade the final effluent
as more and more sludge-builds up in the lagoons. During the GCP, very good
50
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sludge production data was compiled. It was documented that 0.82 kg of sludge
was produced in the activated sludge plant for every 1.0 kg of BOD^ removed
by the activated sludge plant. At design 8005 loading this would result in
the production of 500 kg (1100 Ib) of sludge per day to be discharged to the
lagoons.
>
Process Flexibility was also a critical design factor in that no flexi-
bility existed to bypass the aerated polishing lagoons. The activated sludge
plant, when operated properly, produced a higher quality effluent than was
often attainable from the lagoons. In fact, repeated effluent violations
occurred because of extensive algal growth in the lagoons. Presently, only
secondary treatment is required, however, the wasteload allocation plan
developed for the river indicated that nitrification will also be required.
Ammonia concentrations from the ponds will be almost impossible to control,
whereas almost complete nitrification has been documented in the activated
sludge plant. The ability to discharge clarifier effluent through the lagoon
.when desired would still be a valuable operational tool during mechanical
breakdown or periods of poor sludge character, but the present inability to
bypass the ponds is felt to be a serious limitation.
A third factor which could limit plant performance in the future is the
design organic loading on the aerator of 1300 gm BOD^/cu m/day (81 Ib
BOD5/1000 ft3/day). This is an extremely high loading at which to retain
control of sludge settling characteristics. Presently, wastewater strength
has been considerably less than design at about 500 gm BOD5/cu m/day
(31 Ib BOD5/1000 ft3/day).
Performance
The objective of the CCP demonstration was to demonstrate the potential
improved performance that could be achieved if design modifications would have
been included in the CCP. Demonstrated improved effluent quality would
require the addition of a pond bypass. Effluent quality for the 22-week
period during which the CCP was implemented is presented in Table 9. This
data shows that the activated sludge plant can produce considerably better
effluent quality than the ponds . Clarifier effluent BOD5., TSS and ammonia
were all less than half the corresponding values for pond effluent.
Discussion
At Plant 074 important performance-limiting factors were eliminated,
specifically, inadequate operator application of concepts and testing to
process control and improper technical guidance. However, another major
factor, inadequate process flexibility to bypass the ponds, was not addressed.
Using the "Unified Concept" present in Section 6, the position of Plant 074
would have been a considerable distance away from the goal of optimum perform-
ance, because several major design factors existed as. well as operations
factors. Elimination of the operations factors moved Plant 074's position
closer to the goal of optimum performance. However, plant effluent quality
was not improved. Regardless of how well the mechanical plant is operated,
the final plant effluent quality will not improve until the major design
factors are addressed.
51
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TABLE 9. SECONDARY CLARIFIER AND FINAL EFFLUENT QUALITIES FOR PLANT 074
Week
1978
6/25 - 7/1
7/2 - 7/8
7/9 - 7/15
7/16 - 7/22
7/27 - 7/29
7/30 - 8/5
8/13 - 8/19
8/20 - 8/26
8/27 - 9/2
9/3 - 9/9
9/10 - 9/16
9/17 - 9/23
9/24 - 9/30
10/1 - 10/7
10/8 - 10/14
10/15- 10/21
10/22- 10/28
10/29- 11/4
11/4 - 11/11
11/12- 11/18
11/19- 11/25
Clarifier Effluent
BOD5 TSS | NH3
(mg/1) (mg/1) (mg/1)
10
17
10
—
—
10
8
11
7
12
6
8
5
5
6
11
8
8
8
7
6
30
17
15
19
14
12
11
9
8
17
11
18
13
19
18
23
16
16
16
12
13
__
—
—
—
—
—
—
;
0.0
0.0
, 0.0
, 0.0
0.0
0.0
0.0
0.0
0.5
0.8
: 0.9
0.5
0.8
!
Final Effluent
BOD5 TSS NH3
(mg/1) (mg/1) (mg/1)
43
43
24
—
17
12
9
17
—
32
23
26
15
14
14
15
14
14
14
12
11
46
55
52
51
41
46
32
39
30
49
36
28
28
25
30
31
29
29
30
33
33
__
—
—
—
—
—
—
—
0.0
0.2
' 0.2
0.4
0.0
0.0
0.0
0.0
0.8
1.2
1.5
1.9
2.3
Average
8.5
16
0.3
20
38
0.7
This example points out the Importance of addressing all performance-
limiting factors when conducting a ;CCP. In the case of Plant 074 additional
requirements of the CCP would have teen to make the plant administrators aware
of the needed improvements for the treatment facility and to gain their
support to complete the required modifications.
CCP AT PLANT 097 - '
Plant 097 is a contact stabilization activated sludge facility designed
to treat an average daily flow of 3785 cu m (1 mgd). Recent wastewater flow
has averaged 1890 cu ra/day (0.5 mgd). The present organic loading on the con-
tact and reaeration tanks is approximately 350 g/day/cu m (22 lb/day/-
1000 cu ft). Based on daily average plant flows, the surface settling rate on
the clarifier is 13 cu m/day/sq m [(315 gal/day/sq ft). Sufficient capacity
exists to easily treat the design flow if process control is practiced.
Chlorine disinfection facilities are provided but not utilized since current
state regulations do not require disinfection. Stabilization of wasted sludge
occurs in an aerobic digester, and a combination gravity/pressure filter is
used for concentration of digested sludge prior to ultimate disposal.
52
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Historical records on effluent quality indicated that standards were met
in most cases; however, occasional violations were documented. Inspection of
the receiving stream revealed significant deposits of sludge. According to
plant personnel, periodic infiltration/inflow caused hydraulic overloading of
the secondary process to the point where substantial solids washout occurred.
It was felt that conducting a CCP would result in improvement in maintaining a
high quality effluent.
CCP Implementation
During the initial survey the plant director provided most of the infor-
mation. However, additional information was obtained through conversations
with the plant operators. It became apparent during the evaluation that some
conflicts existed among the plant staff. The city had recently hired a new
plant director creating ill feelings among existing personnel. However, since
the director's appointment, some needed improvements had occurred at the
plant; consequently, the city's decision to change the staffing situation
appeared to be beneficial. However, the plant personnel problems became more
paramount as the CCP progressed.
Several potential areas existed where plant performance could be im-,-
proved, including process control for the activated sludge and aerobic
digester systems. An alternative control method was introduced, and the plant
staff was trained in this new approach. Operation of the sludge dewatering
equipment was also investigated and potential areas for cost savings became
apparent. Continued operational assistance was discussed with the plant
director who agreed that continued operational assistance would be beneficial.
Assistance was continued through monitoring process control records and tele-
phone consultation.
Factors Limiting Performance
Several changes were implemented with respect to process control of the
activated sludge and aerobic digester systems. Prior to the survey, sludge
was wasted from the return sludge line on a daily basis for a selected period
of time. With the implementation of a controlled sludge inventory, a selected
mass of sludge was wasted each day by measuring the waste sludge concentration
and volume.
Operation of the aerobic digester was also modified. Supernatant was
removed from the digester on a regular basis; however, the digester basin
level would always equalize with the aeration basin level within a few hours.
Through the assistance .of the plant design engineer, it was determined that an
open valve existed between these two basins. To allow independent operation
of the digester and aeration basin, this valve was permanently closed. The
digester was then operated in the draw-and-fill mode. Supernatant was pumped
from the digester to the aeration basin on a daily basis, and the digester
concentraion gradually increased to approximately twice the original level.
The draw-andfill operation also affected sludge dewatering. Prior to the sur-
vey the sludge dewatering equipment had been operated on an almost day-to-day
basis, requiring a significant amount of operator time and expenditures for
sludge conditioning chemicals. Once normal digester operation was
53
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established, operation of the dewatering equipment was decreased to one to two
times per week, substantially reducing sludge handling cost.
As the CCP effort progressed, other factors began to limit performance.
Previously, the digester was actually operated as part of the aeration system.
By closing the valve the sludge mass in the activated sludge system was
reduced approximately 40 percent. This sudden change in system mass induced a
change to poorer settling sludge The poorer concentration sludge caused'the
sludge blanket level in the final clarifier to increase. An attempt was made
to return to desired characteristics by maintaining close process control.
A problem developed with respect t|o sludge distribution among the contact,
reaeration and clarifier basins. An opening was provided to allow the reaera-
tion basin sludge to enter the contact tank. However, mixing occurred in both
directions thus diluting the reaeration basin contents and making mass distri-
bution control difficult. To effectively change sludge characteristics, an
overflow gate was needed between the contact and reaeration basins. This
minor design change was discussed with the plant director, but no progress was
made. The director was more concerned about the blanket level in the clari-
fier. It is noted that the sludge blanket level had never been measured prior
to the CCP. A scum layer, which had developed on the final clarifier, was
also a serious concern of the director since the plant was being considered
for a state award. Site visits would have been required to discuss these
items with the director and to continue the CCP activities in an effective
manner.
Performance
During the two-month CCP effort BODg and TSS concentrations in the
effluent averaged 8 mg/1 and 4 mg/1, respectively. The recorded respective
BOD5 and TSS levels for a 7-month period prior to the survey averaged 26
mg/1 and 38 mg/1. However, these concentrations were suspected to be higher
than reported since significant deposits of sludge were noted at the plant
outfall. Improved sludge handling also resulted from the CCP effort. Opera-
tion of the sludge concentrator was reduced from seven days per week to 2-3
days per week. The reduced manpower, chemicals and power requirements sub-
stantially decreased the sludge handling cost, although no data was collected
on the magnitude of this cost reduction.
Discussion
Since significant transfer of capability to plant personnel was not
achieved, sustained high quality effluent is not anticipated. The plant
director was more interested in the1 esthetics of the treatment facility than
in achieving long-term process stability. Site visits should have been con-
ducted to involve city administrators to the point that more authority over
training of the plant staff could bje achieved. The involvement of the state
regulatory agency would also have been beneficial so that1 the importance of
long-term stability could have been discussed. This is expecially important
since the state was planning on giving an award to Plant 097.
54
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CCP AT PLANT 085
Plant 085 is an oxidation ditch activated sludge facility designed to
treat an average flow of 3785 cu m/day (1 mgd). The average flow to the plant
is 85 percent of design; however, infiltration/inflow often constitutes a sig-
nificant portion of the wastewater volume. Wastewater detention time in the
oxidation ditch was designed at 30 hours. At design flow a surface settling
rate of 23 cu m/day/sq m (550 gpd/ft^) would exist in the peripheral feed
final clarifier. A chlorine contact basin is provided for disinfection. Pro-
visions are made for wasting sludge from the return sludge line to two storage
lagoons. Prior to the research survey the plant personnel had experienced
problems with containing the sludge solids within the activated sludge system.
Because of the conservative plant design, it was felt that increased process
control would result in stable performance.
CCP -Implementation
During the initial survey, process control procedures were implemented
to provide the basis for control strategies. Both plant operators had limited
experience in the wastewater treatment; therefore, it was necessary to extab-
lish modified process control procedures. The capabilities of performing the
control tests and recording the associated data were developed, but the abil-
ity to interpret the results and implement process changes required further
development. Operational assistance through telephone consultation was imple-
mented to continue operator training and to obtain plant .stability. Plant
personnel also completed a weekly summary of process control results for
research personnel.
Factors Limiting Performance
At Plant 085 operator application of concepts and testing to process con-
trol was the highest ranking factor limiting performance. This factor was
addressed by providing operator training and implementing a process control
program. Mass control in the activated sludge system was developed to control
solids loss from the final clarifier.
Maintaining a selected mass in the activated sludge system required regu-
lar wasting to the storage lagoons. Because of the limited capacity of these
facilities, sludge wasting capability .was noted as the second highest factor
limiting performance. The city engineer was made aware of the limited .capa-
city and preliminary investigations were made into alternative sludge handling
methods. No definite decisions were made. Toward the end of the CCP activi-
ties, the sludge lagoons approached capacity, and the plant personnel made the
decision to reduce the wasting from the activated sludge system. This
approach provided a short-term solution to the sludge handling problem, but
degraded effluent quality is expected in the future.
Prior to the survey a considerable amount of operator time was being
spent in the laboratory. With the addition of process control testing the
laboratory work load became overwhelming. An evaluation of all tests .perform-
ed at the plant was made in an attempt to determine the need for each test.
The state regulatory agency was contacted, and the tests required by the NPDES
55
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permit for monitoring and operation: were determined. Many of the tests being
conducted were not necessary and the laboratory schedule was revised. As a
result, operator time in the laboratory was minimized, permit testing require-
ments were achieved, and process control tests were incorporated into the
schedule. ;
The results of the BOD5 test indicated a poorer quality effluent than
noted by visual inspection. The suspicion of the 8005 results was further
supported by the relatively good quality of TSS concentrations in the plant
effluent. An evaluation of the BOD5 testing procedures showed that the
results were obtained inaccurately.; Reliable BODg results were finally ob-
tained, but much of the data prior Ito and during the CCP was questionable in
value. i
- !
Performance
Historical records showed that the plant typically met effluent stand-
ards, but plant personnel reported that solids loss from the final clarifier
had occurred on a frequent basis. When operated properly, Plant 085 produced
a good quality effluent. However, i with the limited sludge handling facili-
ties, degraded effluent quality was [expected to resume in the future.
Discussion
To conduct a completely successful CCP, a higher level of effort would be
required than that expended during the research project. A major effort was
directed towards improving operator application of concepts and testing to
process control. However, becausei of the limited experience of the plant
operators, the required degree of training was not possible. Consequently,
the operational capability of the piant staff is still limiting performance.
The lack of adequate sl-udge handling facilities let to the termination .of
sludge wasting. Since no provision for achieving required wasting in the
future was pursued, effluent quality is expected to deteriorate. Plant opera-
tors and administrators will require incentives other than those provided by
the CCP demonstrations before they will pursue expanded sludge handling capa-
bilities. ;
CCP APPLICATION TO THE 50 RESEARCH EjACILITIES
i
• -
The CCP approach was implemented with varying levels of success at seven
facilities during Phases I and II. In several of these plants, performance
limiting factors still remained presenting achievement of desired plant per-
formance. While the CCP approach |was still applicable, a higher level of
effort would have been necessary to!eliminate all of the factors. In almost
all of these demonstrations additional time was needed for such efforts as
site visits, evaluation of design limitations, additional operator training,
and meetings with state and federal' regulatory personnel, plant design engi-
neers and plant administrators. Despite the limitations of the CCP demonstra-
tions conducted under the scope of this research significant improvements in
plant performance were documented. ; Based on these results, an evaluation of
the potential impact of the CCP approach on the fifty facilities studied under
56
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this research was completed. The individual facility evaluations are included
in Appendix H. Only thirteen of the fifty facilities studied consistently met
secondary treatment standards. Using the CCP approach and excluding the
option of a major design modification, forty of the fifty facilities evaluated
could consistently meet secondary standards. Table 10 presents a summary of
this evaluation. An additional 27 plants could consistently meet secondary
treatment standards without major facility modifications.
TABLE 10. PERFORMANCE OF 50 PLANTS EVALUATED VERSUS SECONDARY TREATMENT
STANDARDS
Prior to Research
Potential After CCP
Standards Frequently Violated
Standards Consistently Met
37
13
10*
40
*Major facility modifications would be required for these facilities to
consistently meet secondary treatment standards (9 of 10 of these
facilities were trickling filters - See Appendix H).
The dramatic impact of the potential improved performance is supported
by further evaluation of all facilities (See Appendix H) . This evaluation
indicated that the performance of 38 facilities could be improved using the
CCP approach. The potential reduction of BODj and TSS being discharged to
receiving streams was estimated to be 1020 metric tons/year (1120 tons/year)
and 1190 metric tons/year (1315 tons/year), respectively.
The potential improvement in effluent quality from existing wastewater
treatment facilities warrants the consideration of implementing the CCP
approach on a broad scale. However, implementation of CCPs requires qualified
personnel and incentives to encourage the program's use (4, 5). Personnel who
implement CCPs must be able to recognize performance limiting factors in the
broad areas of design, operation, maintenance and administration. These
people must then be able to implement programs over a long enough time period
to insure that desired performance is ' achieved and maintained. It is not
intended that present programs be eliminated and replaced with the CCP pro-
gram. A properly implemented CCP would utilize existing programs, as neces-
sary, to correct the unique combination of factors limiting performance at a
particular facility. The CCP is then more of an overall coordination effort
implemented by technically competent individuals.
Two recent articles summarize workshop and committee activities of groups
developed to address the plant performance problem (6, 7). A major emphasis
of these efforts was to describe the roles of each of the various categories
of individuals involved with wastewater treatment plant performance. Categor-
ies of individuals included: operators, plant managers, consultants, munici-
pal officials, regulatory personnel, equipment manufacturers, training person-
nel, and the public. Role definition for each group was very difficult. If
an overall objective like CCP implementation is adopted, the coordinated
effort of all these groups can be better developed. Limited examples of roles
for operating personnel, plant managers and municipal officials, regulatory
57
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agency personnel, equipment suppliers and consultants are presented:
Operating Personnel
- Improve sewage treatment understanding through training and certifica-
tion, j
- Develop an awareness of the broad range of factors that can limit per-
formance such as design and administrative problems, and seek technical
assistance in addressing these problems (i.e. CCP).
- Accept operations assistance '•• that is provided during a CCP as a learn-
ing experience that will improve qualifications rather than view it as
a reflection of poor capabilities.
i
Plant Managers and Municipal Officials
- Verify performance potential of existing facilities.
- If a CCP is warranted, require that it be conducted by qualified per-
sonnel.
- Provide an environment for operating personnel to improve sewage treat-
ment understanding through budget support for training and certifica-
tion. ' ,
- Recognize that on-site training is the most effective way to develop an
operator1s capability to properly apply wastewater treatment concepts
to process control.
- Realize that a well trained operator is an investment in the success of
a facility's performance andi strive to retain this investment through
an adequate salary and benefit schedule.
Regulatory Agency Personnel
- Expand enforcement of NPDES Permits to provide incentives for imple-
menting CCPs at facilities which do not meet standards.
- Require that the performance potential of an existing facility is
adequately assessed before construction of new or modified facilities
are implemented.
- Structure information dissemination and training programs to emphasize
the higher ranking factors limiting plant performance defined in this
research.
- Improve qualifications of personnel to avoid frequent occurrence of
improper technical guidance.
i
Equipment Suppliers
- Provide flexibility and controllability in equipment and associated
processes that are marketed, i
— Present realistic assessments of operation and maintenance requirements
for equipment and associated processes.
- Expand qualifications of personnel for start-up services to avoid the
occurrence of improper technical guidance concerning wastewater treat-
ment . j
Engineering Consultants !
- Improve design of new or modified wastewater treatment facilities,
especially for those high ranking design deficiencies observed during
this research. :
58
-------
Improve qualifications of personnel to avoid frequent occurrence of
improper technical guidance. Training should include in-plant
operations experience where personnel are in a position to be held
accountable for their recommendations.
Develop capabilities to implement Composite Correction Programs.
59
-------
SECTION 8
SELECTED EVALUATIONS
Special evaluations were madej regarding specific groupings of factors
limiting performance. Some of these evaluations were made because they were
specificlly requested by EPA, and o|thers were made to address major perform-
ance-limiting factors determined in this research. Presentation of these
evaluations is not intended to imply that significant improvement in plant
performance will occur by addressing these factors. Each topic presented may
represent only a portion of the overjall problems at a particular plant.
AERATORS>
Inadequate aerator capability wjas the ninth highest ranking factor limit-
ing performance. The term aeratorjrefers to the facility utilized for the
conversion of soluble and colloidal organic matter into settleable organic
matter. The aerator factor was ranked when size of the aerator was adversely
affecting plant performance. The data has been separated into three different
categories: activated sludge aeration basins preceeded by clarifiers,
activated sludge aeration basins not preceeded by clarifiers, and fixed film
aerators. '<
Activated Sludge Aeration Basin Preceeded by Clarifier
__ i
t [
Six of the 36 activated sludge facilities in which a comprehensive
evaluation was made had primary clkrifiers preceeding the activated sludge
process. A summary of the aeration basin organic loading for these facilities
is shown in Table 11. j .
TABLE 11. AERATION BASIN ORGANIC LOADING .
AT ACTIVATED SLUDGE PLANTS WITH PRIMARY CLARIFIERS
Plant
No.
027
038
066
068
075
092
Plant
Type
AS
AS
AS
AS
AS
AS
Actual
mgd* %
5.5
3.14
0.71
5.4
5.8
3.12
Flow
Design
55
70
76
98
64
57
Ib BOD/day/
Operating
1
24
3^
20
31
31
36
1000 cu ft**
Design
' 62
41
52
56
45
Standards
Met
X
X
X
Standards
Not Met
X
X
X
*
*mgd X 3785 - cu m/day; **lb/day/1000 ft3 X 16.0 = gm/day/cu m
'• 60
-------
As shown, activated sludge facilities with primary clarifiers had an
average flow of 14,950 cu m/day (3.95 mgd). One facility had a wastewater
flow rate less than 3,785 cu m/day (1 mgd), The average operating organic
loading was 460 gm/day/cu m (29 lb/day/1000 ft3) which was 60 percent.of the
average design loading. The average organic loading for those plants meeting
standards was the same as the loading for those plants that violated stand-
ards. Therefore, no correlation between aeration basin loading and improved
performance existed.
Activated Sludge Aeration Basin Not Preceeded by Clarifier
The remaining 30 of 36 activated sludge plants evaluated did not use pri-
mary clarifier prior to the activated sludge process. Sixteen of these thirty
plants were extended aeration, five were contact stabilization, and nine were
activated sludge categorized as conventional. A summary of the organic load-
ing for these thirty facilities is shown in Table 12. For contact stabiliza-
tion plants both the reaeration and contact tanks were included in the calcu-
lation of aerator volume.
The average aeration basin organic loading for this category of plants
was 290 g/day/cu m (18 lb/day/1000 ft3), which was about 64 percent of .the
average design loading. The average operating flow rate was 1250 cu m/day
(0.33 mgd). Organic loading versus plant flow rate is shown in Figure 15.
Considerable scatter exists in the plotted data, but aerator loading appears
to slightly increase with increased flow rate.
70
Rfl
AERATION BASIN LOADING
Ib BODS/ DAY/ 1000 FT 3
_i 10 « *. en <
o 0 0 00 0 0 <
• STANDARDS MET
O STANDARDS NOT ME1
JO
.01
O
>(>
•
-
: o
B 8
0.1
I
•
3
*.,-
O
»
<*'<
0
.
*
1.0 10JO
I PLANT. FLOW I MGD I
figure 15. Organic loading of activated sludge plants without primary,
clarifiers (lb/day/1000 ft3,x 16 = gm/day/cu m).
61
-------
TABLE 12. ORGANIC LOADING AT ACTIVATED
SLUDGE PLANTS WITHOUT PRIMARY CLARIFIERS
Plant
No.
002
007
013
014
019
020
021
022
026
028
029
039
047
048
050
051
052
053
055
061
062
063
065
074
077
080
082
085
086
097
Plant
Type
ASEA
ODEA
AS
AS
ASEA
ASEA
ODEA
ASEA
ASEA
ASCS
AS
ODEA
ASEA
AS
ASEA
ASEA
ASEA
ASEA
ASEA
ASCS
ODEA
AS
ASCS
AS
AS
AS
ASCS
ODEA
ASEA
ASCS
Actual
mgd* %
0.43
0.041
6.5
1,0
0.035
0.007
0.59
0.012
0.15
0.15
1.37
0.21
0.05
0,34
0.17
0.21
0.045
0.11
0.30
0.17
0.20
0.70
0.13
0.30
0.24
0.25
0.083
0.84
0.48
0.84
Flow
Design
54
59
63
50
54
28 .
66
80
30
60
78
51
80
89
96
75
60
68
52
34
59
47
87
86
78
60
69
86
48
84
Ib BOD/ day/
Operating
8.8
7.4
37 i
37 ,
19 !
3.5;
8.3
4.0
5.2
20 :
61
13 [
6.4
35
11 i
48
5
10
7
12
5.6
10
29
31
25
18
28
9.7
8.9
22
1000 cu ft** Standards
Design Met
13
15
46
47
— ,
12
X
7.2
X
—
74
—
—
—
14
18
^_» V
14
14 X
34
12 X
—
32
81
38
36 X
—
11
15
35
Standards
Not Met
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
urn.
In^Figure 15, plants that met standards are denoted by the shaded points.
A definite correlation exists betweefr a low aerator loading and plants meeting
standards. Except for one plant iwith a loading of 290 gm/day/cu m (18
lb/day/1000 ft3), the six plants that met standards had organic loadings of
less than 160 gm/day/cu m (10 lb/day/ 1000 ft3). Conversely, nine plants
that violated standards also had aerator loadings less than 160 gm/day/cu m
(10 lb/day/1000 ft3). Conservative aerator loadings appear to aid in
improvement of plant performance, b|ut are neither a guaranteed solution nor
cost effective. |
The highest loaded activated sludge plant evaluated had an aerator load-
ing of 976 gm/day/cu m (61 lb/day/l|000 ft3). At the time of the comprehen-
62
-------
sive evaluation this plant was not consistently meeting standards. Through a
CCP the plant was brought into compliance and now consistently meets standards
with an average effluent 3005 and TSS concentration of about 10 to 15 mg/1
(4). This improvement occurred without a major facility upgrade and indicates
that aerator loading was probably not the factor limiting performance of the
other activated sludge plants that were violating standards. These plants
could probably be brought into compliance without major capital expenditures
for aeration capacity. It also suggests that many plants may have a tremen-
dous reserve capacity in terms of aeration capability and probably could
handle additional wastewater flow without major capital improvements. Thus,
through better plant operation, plant effluent quality can be improved and
capital cost savings can be realized.
Fixed Film Facilities
Fixed film facilities evaluated included two using rotating biological
contactors, two using activated bio-filters, and ten using trickling filters.
A summary of aerator organic loading for these facilities is shown in Table
13. The rotating biological contactor facilities (RBC) were separated from
the other plants, because the organic loading for RBC units is more accurately
expressed as mass per unit surface area.
TABLE 13. ORGANIC LOADING AT FIXED FILM TREATMENT PLANTS
Plant
No.
012
015
024
032
034
035
036
041
060
069
070
095
Plant
Type
TF/CS
TF
ABF
TF
TF
TF
TF
TF
ABF/TF
TF
TF
TF
Actual
mgd* %
8.1
1.7
4.9
0.22
5.5
5.3
1.6
0.13
0.49
0.08
1.10
1.2
Flow
Design
68
47
82
50
68
98
87
33
47
114
100
48
Ib BOD/ day/
Operating
71
29
90
31
19
12
11
12
61
13
9.6
29
1000 cu ft**
Design
92
—
147
—
27
12 -
31
—
94
• —
12
72
Standards
Met
X
X
X
X
Standards
Not Met
X
X
X
X
X
X
X
X
Ib BOD/DAY/1000 sq. ft.***
040
093
RBC
RBC
3.7
1.4
4.3
4.4
X
X
*mgd x 3785 = cu m/day; **lb/day/1000 ft3 x 16 = g/day/cu m;
***lb/day/1000 sq ft x 4.885 = Kg/day/1000 sq m
The two RBC facilities had dramatically different loadings but at the
time of the evaluation neither facility consistently met standards. The more
lightly loaded facility exceeded standards because of problems with aerator
.63
-------
sn
TRICKLINQ FILTER ORGANIC LOADING
lbBOD,/DAY/1000FT3
0 3 S 8 § S S 3
• STANDARDS MET
O STANDARDS NOT UE1
:
I
0 •
r
a
^
I
1
O O
^••1t
I
.
oat
0.1 1.0
PLANT FLOW IMGDI
100
Figure 16. Organic loading of fixed
film facilities (lb/day/1000 ft3 x
16 = gm/day/cu m).
loading. Subsequent to the evaluation
this plant had better experience with
the shafts on the RBC unit and permit
standards were met. At the more heav-
ily loaded facility permit standards
were continually violated. Both RBC
facilities were operating at organic
loadings less than design values, i at
86 percent for the more heavily loaded
plant and 32 percent for the other
facility. From this limited data,[it
appears that a more thorough evalua-
tion of RBC capabilities and design
loadings is warranted. |
At the other fixed film facili-j-
ties the wastewater flow averaged
9,575 cu m/day (2.5 mgd) and the
average organic loading was 510
gm/day/cu m (32 lb/day/1000 ft3). | A
graph of organic loading versus flow
for these plants is shown in Figure
16. The shaded points indicate plants
that met standards. As shown, only
four plants met standards on a con-
sistent basis. These plants were| operating at the lower organic loading
rates. Only one plant that was operating at a similar loading violated stand-
ards. Further evaluation of this facility indicated that poor performance was
associated with inadequate sludge removal from the secondary clarifier, inade-
quate recirculation capability, and, trickling filter freezing problems during
the winter.
The results indicate that conservatively designed fixed film aerators are
necessary to meet permit standards.! However, the extent of this conservative
design is not necessarily related directly to the specific low organic loading
values shown in Figure 16. Other performance limiting factors exist, as evi-
denced by the lightly loaded trickling filter plant that violated standards.
Therefore, some of the more heavily loaded facilities may be able to meet
standards if other performance-limiting factors were corrected. Each facility
must be individually evaluated but the trend for better-performance for con-
servatively loaded' fixed film plants was apparent.
Overall Aerator Evaluation
The aerator represents a key aspect in a system's capability for meeting
standards. The results from this evaluation indicated that most plants that
met standards had lower levels of organic loading. The results for the fixed
film systems were more conclusive in relating aerator loading to plant per-
formance, in that all fixed film plants that met standards had lower organic
loadings. The suspended growth systems showed that most of the plants that
met standards had a low aerator organic loading, but at the same time, many
lightly loaded suspended growth pl'ants violated standards. The conclusion
from these results, coupled with field observation, was that fewer operational
problems existed for fixed film facilities which enabled them to
64
-------
meet standards when they had a low loading rate. .More operational problems
existed for the suspended growth facilities, as evidenced by the fact that
quite a few activated sludge plants,:violated, standards even though they had a
low loading rate. The overall conclusion was that low organic loading of the
aerator tends to "mask" other performance-limit ing problems and allows these
plants to meet standards. However, low organic loading does not guarantee a
good plant effluent nor is it cost effective.
• - £ \
For fixed film systems with higher organic loadings, permit violations
are more apt to occur. For these systems major capital improvements would be
requried to allow consistent compliance. For suspended growth systems
improved operations could significantly improve plant performance. Further-
more, additional plant capacity could be achieved. Thus, improved plant oper-
ations could improve existing plant performance and save expenditure for unre-
quired capital improvements.
CLARIFIER DESIGN
Sixteen of 50 facilities evaluated during Phase I and II were limited to
some degree by inadequate secondary clarifier design. As such, secondary
clarifier was the tenth highest ranking factor and warrants further discus-
sion.
Characteristics of the secondary clarifiers for the 50 facilities evaluated
are shown in Table 14. About 75 percent of the plants used circular clarifi-
ers. The majority of these clarifiers (80 percent) were of the center-feed
type. Typically, rectangular clarifiexs were found in small extended aera-
tion, activated sludge plants.
In general, conservative clarifier overflow rates existed. For suspended
growth plants, the average clarifier overflow rate was 14.5 cu m/day/sq m (355
gal/day/ft2). For the fixed film plants the average overflow rate was 19.4
cu m/day/sq m (475 gal/day/ft2). These overflow rates are considerably less
than a reasonable design overflow rate! of 24 cu m/day/sq m (600 gpd/ft2).
The conservative values indicate that with good operational control signifi-
cant capacity should be available in existing clarifiers.
Design Limitations
Despite conservative overflow rates, several hydraulic problems limited
performance at some facilities. The most critical problem was inadequate
development of the clarifier surface area with effluent launders. Of seven
facilities identified with this problem, six were rectangular clarifiers with
effluent launders located at one end. In these facilities, excessively high
upflow velocities in the area of the weirs caused washout of sludge solids.
This situation could have been improved by additional weirs to enlarge the
upflow area.
One recently constructed circular clarifier was a 27.4 tn (90 feet) diam-
eter peripheral-feed/peripheral withdrawal unit. Excessive solids washout due
to shortcircuiting occurred in this clarifier even when good sludge settling
characteristics existed and a low blanket depth was measured near the center
65
-------
TABLE 14. CHARACTERISTICS OF SECONDARY CLARIFIERS
AT THE 50 COMPREHENSIVE SURVEY FACILITIES
Plant
No.
002
007
012
013
014
015
019
020
021
022
024
026
027
028
029
032
034
035
036
038
039
040
041
047
048
050
051
052
053
055
060
061
062
063
065
066
068
069
070
074
075
077
080
082
085
086
092
093
095
097
Survey Plant
Date
1975
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1978
1976
1976
1977
1976
1976
1977
1977
1977
1977
1977
1977
1977
1977
1977
1977
1977
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
Actual Flow
Type cu in/day
ASEA
ODEA
TF/CS
AS
AS
TF
ASEA
ASEA
ODEA
ASEA
ABF
ASEA
AS '
ASCS
AS
TF
TF
TF
TF
AS
ODEA
RBC
TF
ASEA
AS
ASEA
ASEA
ASEA
ASEA
ASEA
ABF
ASCS
ODEA
AS
ASCS
AS(2)
AS
TF
TF
AS
AS
AS
AS
ASCS/TF
ODAS
ASEA
AS
RBC
TF
ASCS
1,628
155
30,660
1,892
3,785
6,434
132
26
2,233
45
18,550
568
20,820
568
5,185
833
20,820
20,060
6,056
11,880
795
1,438
492
189
1,287
643
795
170
416
1,136
1,855
643
757
2,650
492
2,687
20,440
303
4,164
1,136
21,950
908
946
314
3,179
1,817
11,910
8,327
4,542
3,179
mgd % Design
0.43
0 :041
8Jl
0.5
1JO
U7
0.035
0.007
0:59
0:012
4:9
ohs
5J5
oils
1:37
OJ22
5:5
5>3
116
3ll4
Oi21
0>38
0;13
0:05
0^34
OU7
0121
01045
Oill
opo
0^49
0;17
0120
°f7
0 13
0171
5.4
0.08
1,10
0130
5,8
0*24
Of25
0.083
0.84
01.48
3ll2
2l2
ill
0.84
54
59
68
63
50
47
54
28
66
- 80
69
30
55
60
78
50
68
98
87
70
51
60
33
80
89
96
75
60
68
52
47
34
59
47
87
76
98
114
101
86
64
78
60
69
86
48
57
44
48
84
Clarifier*
Type
R
CPF
CCF
R
CCF
CPF
R
R
CPF
R
CCF
N/A
CPF
CCF
CCF
CCF
R & CCF
CCF
CCF
CPF
CPF
CCF
R
R
CCF
CCF
R
R
R
. CCF
CCF
CCF
CCF
CPF
CCF
CCF
CCF
R
CCF
CCF
CCF
CCF
CCF
R & CCF
CPF
CCF
CCF
CCF
CCF
CCF
Clarifier Overflow
Rate gpd/£t2**
Operating Design
190
270
520
770
370
340
100
60
250
190
' 560
600
860
350
350
310
560
590
170
440
300 .
300
1000
250
480
300
250
230
180
310
300
180
280
280
510
360
670
630
750
210
300
380
310
440
480
190
350
280
380
530
350
460
760
740
520
730
190
200
380
240
800
2000
790
580
460
710
810
610
280
640
580
500
1000
314
540
310
330
390
270
600
650
530
240
600
590
480
680
560
690
250
500
510
520
560
550
400
550
650
790
630
*R " Rectangular; CPF = Circulkr Peripheral Feed; CCF
**gpd/ft2 x 0.0408 - cu m/day/sq m.
» Circular Center Feed.
66
-------
of the clarifier. Installation of additional weirs and effluent launders at
incremental intervals toward the center of the clarifier would have improved
performance of this unit.
In several plants using circular, center-feed clarifiers, short-circuit-
ing from the center inlet baffle to the peripheral effluent weirs was
observed. An opening in the inlet baffle which was designed to allow for the
escape of floating materials and scum from the center ring of the clarifier
allowed this shortcircuiting to occur. Solids loss with this design arrange-
ment was not critical with a relatively well settling sludge in the system,
but was critical and allowed abnormally high effluent TSS concentrations when
activated sludge settling characteristics were slower than desired. At Plant
029 (4) the problem was solved by closing up the scum outlet port and removing
the accumulated scum manually.
In several small activated sludge and trickling filter plants mechanical
sludge collecting mechanisms were not provided. The intent was to have the
plant operator aid sludge removal by manually scraping down the hoppered bot-
toms of these clarifiers on ,a daily basis. A problem was observed when suf-
ficient manpower was not available or provided to complete this task. As a
result, effluent quality deteriorated because of sludge build-up in the clari-
fier. To solve this problem either major design modifications would be neces-
sary or better operations priorities established.
Design Innovations >
Some facilities surveyed had clarifiers that were particularly conducive
to achieving good plant performance. An advantageous design was final clari—
fiers with a side water, depth of 4.5 meters (15 ft) or greater. During peak
flow periods these deep clarifiers demonstrated an ability to absorb a high
solids loading and associated increased sludge blanket level without allowing
a degraded plant effluent quality. In addition, less stringent operational
control was necessary because the need for close return sludge flow control
was minimized. Another advantage occurred when bulky sludge conditions exist-
ed. In this case," a thick return sludge concentration would normally be dif-
ficult to maintain, but with deep clarifiers a reasonably thick return sludge
concentration could be maintained due to sludge build-up and additional time
for sludge thickening.
Another advantageous design arrangement was noted for clarifiers that had
separate clarifier return sludge and waste sludge removal mechanisms'. For
these clarifiers, a rapid withdrawal sludge collection mechanism was used to
return sludge to the aeration basin, and waste sludge was taken from a center
hopper that was fed by scrapers on the sludge removal mechanism. This
arrangement was particularly useful at plants that did not have primary clari—
fiers since rags, strings, and other solids would be scraped to the center
hopper and wasted as opposed to being recycled in the return sludge. Also,
the presence of the center hopper for wasting sludge allowed for a higher con-
centration of waste sludge than could be obtained from the return sludge line.
Typically, the waste sludge concentration was found to be two to four times
greater than the return sludge concentration allowing a desired mass of
67
-------
sludge to be wasted using only one-half to one-fourth of the volume that would
have been required if return sludge had been wasted.
SLUDGE PRODUCTION IN ACTIVATED SLUDGE PLANTS WITHOUT PRIMARY CLARIFIERS
The most significant group of performance-limiting factors identified
were those associated with sludge production and wasting requirements in acti-
vated sludge plants. Three design [factors, inadequate sludge wasting capabil--
ity, inadequate ultimate sludge disposal and inadequate sludge treatment
facilities, ranked very high as performance-limiting factors in many facili-
ties. Yet, these design problems were secondary to a more fundamental problem
represented by some higher ranking operations oriented factors: inadequate
operator application of concepts, [inadequate sewage treatment understanding,
improper technical guidance and inadequate process control testing. Regard-
less of the physical facility limitations observed, the available facilities
at most plants were not being used to their capacity. Based on the design and
operations problems observed, it was concluded that much confusion exists con-
cerning sludge production and s.ludge wasting. The following statements,
obtained during the project, further illustrate this widespread problem.
"All activated sludge plants bulk solids periodically - there's nothing
you can do about it." — Plant Superintendent and former full-time
instructor at an operator training school.
i
"I realized that things werenjt just right (referring to daily bulking),
but I was told to keep the MLSS concentration up, even higher than what
it is now." —Plant Operator [
"The engineer said I'd only have to draw sludge (waste) once or twice a
year." —Plant Operator ,
"When the plant was being built, the guy putting in the equipment said I
probably won't have to remove: sludge at all because each time it rains
excess solids will be washed out." —Plant Operator
"I've asked the town's engineer and the state for help in setting up a
wasting program, but nobody seems to know how to go about it." —Plant
Operator. '
"Hardly any of the small plantjs waste sludge on a regular basis. I donft
even mention it unless I have a special request to provide operational
assistance." —State District Engineer
Activated Sludge Mass Control
The fundamental principles governing performance of activated sludge
plants are universal regardless o'f size of facility or type of activated
sludge process. In the activated sludge process total sludge mass will
increase naturally as microogranisms metabolize organic matter in the waste-
water. Whether or not the total activated sludge mass in the system in-
68
-------
creases, decreases or remains constant
depends on how much sludge is removed
voluntarily or involuntarily from the
system in relation to the amount
grown. Graphs indicating the rela-
tionship of sludge mass and wasting
are shown in Figure 17. Time in days
is plotted on the X-axis. The mass of
activated sludge wasted and the mass
of sludge in the activated sludge sys-
tem are plotted on the Y-axis. System
mass and mass wasted are plotted to-
gether to show their close interdepen-
dence. System mass is determined by
mass wasted and can be adjusted by
changing wasting rates.
Figure 18 shows . a conceptual
relationship between sludge mass and
sludge wasting. The naturally occur-
ring daily variations shown in Figure
17 were smoothed out and the more
important aspect of system trends is
emphasized. In the first time period
shown a high level of wasting resulted
in a decrease in the total activated
sludge mass. In this case, wasting
exceeded sludge growth. If wasting is
decreased to a level below sludge
growth, as shown in the second time
frame, the total sludge inventory
increases. In every plant, for cur-
rent loading and growth conditions,
some level of wasting will hold a
relatively constant total sludge
inventory, as shown in the last time
frame of Figure 18.
Although the basic concept is
quite simple, mass control was inade-
quate in most activated sludge plants
surveyed.
Sludge Production
Reliable information on sludge
production was obtained from seven
activated sludge .plants surveyed. The
data presented is supplemented with.
data from four plants with which
research personnel are involved on a
private consultant-client basis.
40
CO
CO 30
20
111
CO
Q
Ul
CO
I
CO
CO
10
CO
CO
DATE
Figure 17. Typical activated
sludge mass control data.
40
30
S 20
ui
CO
10
UJ
CO
I
CO
CO
TIME
Figure 18.
control.
Activated sludge mass
69
-------
Sludge growth and wasting commonly fluctuate for a given plant; therefore,
sludge production data is presented only for facilities with which close con-
tact was maintained for a minimum of three months. The eleven plants evaluat-
ed were located in four states and all were activated sludge plants without
primary clarifiers.
Sludge production data is shojwn in Table 15. Data was collected for a
total of 3,234 operating days for the eleven facilities. Effluent BOD5
varied from 1*.2 mg/1 to 31 mg/1 and effluent TSS varied from 1.9 mg/1 to 24
mg/1. The average effluent BOD5 jand TSS values were 13 mg/1 and 11 mg/1,
respectively, indicating good plant performance.
i
TABLE 15. ISLUDGE PRODUCTION DATA
Actual Flow Days of
% of Data
Facility
Reinbeck, IA
Berthoud, GO
East Canon S.D.,
CO
Marshfield, MO
Grimes , IA
Upper Eagle Val-
ley S.D., CO
Akron, IA
Upper Thompson
S.D., CO
Cresco, IA
S. Fort Collins
S.D., CO
Havre, MT
Plant Type
i
Extended Aeration1
Oxidation Ditch i
j
Contact Stabilization
v Extended Aeration!
Conventional
i
Contact Stabilization
|
Contact Stabilization
!
Conventional
Conventional j
Conventional
with filters ,
Conventional !
mgd*
0.14
0.55
0.43
0.46
0.25
0.91
0.12
0.50
0.50
0.51
1.29
Design Collection
78
61
142
46
85
81
33
133
34
72
122
228
210
231
182
215
364
644
92
216
730
• Total 3234 Average
Effluent
BOD5 TSS
mg/1 mg/1
8.3 5.5
4.0 5.5
7.9 17
7.8 3.9
8.5 14
15 13
29 15
31 24
15 7
1.2 1.9
14 16
13 11
i
*mgd x 3785 - cu m/day ;
To compare
sludge production [for
common basis for documenting sludge
characteristic
plants of various sizes and types, a
produced
of domestic wastewater which
describe the amount of sludge which
was
has
will result ,
necessary.
The single
typically been used to
from biological secondary
70
-------
treatment is the 8005 removed in the process. Thus, sludge production has
been correlated with BOD5 removed to calculate a sludge production ratio.
The units are kilograms of total suspended solids (sludge) produced per kilo-
gram of B0i>5 removed. Because primary clarifiers were not provided, waste
sludge from the secondary system included both net cell production and non-
degradable primary type solids.
In calculating sludge production three components were included: .sludge
intentionally wasted, sludge lost as effluent suspended solids, and changes in
the sludge inventory within the activated sludge system. Over a period of
many months of stable operating conditions, the change in sludge inventory was
usually insignificant compared to waste and effluent sludge. However, when
calculating sludge production on a monthly or shorter basis, changes in sludge
inventory became very significant.
When comparing sludge production values, it was desirable to include
effluent suspended solids since varying effluent qualities could have intro-
duced an unnecessary variable into the evaluation. Accounting for effluent
sludge does lend consistency to sludge production calculations but does not
accurately describe actual sludge wasting requirements. Therefore, a second
sludge to BOD5 ratio, called the sludge wasting ratio, was determined. The
sludge wasting ratio is always less than the sludge production ratio in pro-
portion to the amount of sludge solids lost in the plant effluent. Sludge
production and sludge wasting ratios are listed in Table 16 and are graphical-
ly shown in Figure 19. The sludge production ratios averaged 0.81 and the
sludge wasting ratios averaged 0.75.
TABLE 16. SLUDGE PRODUCTION - Kg TSS PER Kg BODg REMOVED
Facility
Reinbebk, IA
Berthoud, CO
East Canon S.D., CO
Marshfield, MO
Grimes, IA
Upper Eagle Valley
S.D., CO
Akron, IA
Upper Thompson
S.D., CO
Cresco, IA
S. Fort Collins
S.D., CO
Havre , MT
Plant Type
Extended Aeration
Oxidation Ditch
Contact Stabilization
Extended Aeration
Conventional
Contact Stabilization
Contact Stabilization
Conventional
Convent ional
Conventional
Convent ional
Averages
Sludge
Production
Ratio*
0.80
0.60
0.95
0.65
0.82
1.14
1.11
0.79
0.73
0.70
0.66
0.81
Sludge
Wasting
Ratio**
0.78
0.55
0.84
0.63
0.76
1.01
1.03
0.67
0.70
0.69
0.60
0.75
*Includes effluent TSS
**Does not include effluent TSS
71
-------
1.3
1.2
EFFLUENT SLUDGE
' [
|
SLUDGE WASTED
SINGLE-STAGE AERATION
TWO-STAGE AERATION
Figure 19. Sludge production at ^elected wastewater treatment facilities.
Sludge production ratios varied from 0.60 to 1.14. The highest sludge
production ratios were found at contact stabilization (two-stage aeration)
plants. Sludge production for the three contact stabilization plants averaged
1.07 kilograms of TSS produced per kilogram of BOD5 removed. The single-
stage aeration facilities averaged 0.71 kilograms of TSS produced per kilogram
of BODj removed. The limited data [available strongly indicates that a sig-
nificantly greater amount of sludge [is produced in two-stage aeration systems.
If additional data supports this conclusion, increased sludge handling capa-
bility will be necessary when designing contact stabilization plants.
i
Evaluation of Factors Affecting Sludge Production
t
Historically, sludge yield has| been predicted based on mean cell resi-
dence time (MCRT), food to microorganism ratios (F/M) or other parameters
which indicate the amount of endogenous respiration which will likely occur in
the system. Efforts were made to correlate sludge production ratios with four
parameters: MCRT, F/M, wastewater detention time in the aerator (WWDT^),
and volumetric organic loading (gm BOD5/m^/day). These parameters are
summarized in Table 17. The correlation between these parameters and sludge
production ratios were analyzed graphically. Sludge production ratios for
twostage aeration systems were included on the graphs, but not included in the
statistical data analysis. !
Sludge production ratios versus MCRT are shown in Figure 20. The least
squares line of best fit indicates a lower sludge production ratio for a high-
er mean cell residence time. The correlation coefficient (r) indicates the
strength of the linear relationship|between the two variables. An exact cor-
relation would be indicated by a value of _+1.00 while no correlation would be
indicated by a value of zero. The correlation coefficient between the sludge
72
-------
production ratio and MCRT was -0.60. Thus, the linear correlation between
sludge production and MCRT appears to be only fair. The negative value indi-
cates that as MCRT increases, the expected sludge production ratio decreases.
TABLE 17. AVERAGE OPERATING PARAMETERS DURING SLUDGE PRODUCTION EVALUATION
Facility
Aerator Type
Sludge
Production gm 8005/
Ratio MCRT F/M* WWDTA day/m3**
Reinbeck, IA
Berthoud, CO
East Canon S
CO
Marshfield,
Grimes , I A
Upper Eagle
ley S.D. ,
Akron , IA
.D.,
MO
Val-
CO
Extended Aeration
Oxidation Ditch
Contact Stabilization
Extended Aeration
Conventional
Contact Stabilization
Contact Stabilization
0
0
0
0
0
1
1
.80
.60
.95
.65
.82
.14
.11
22
63
21
37
23
34
14
0
0
0
0
0
0
0
.058
.025
.053
.042
.061
.030
.079
29
25
10
26
12
10
11
.5
.2
.6
.7
190
93
290
220
510
240
420
(12)
(5.8)
(18)
(14)
(32)
(15)
(26)
Upper Thompson
S.D., CO
Cresco, IA
S. Fort Collins
S.D., CO
Havre, MT
Conventional
Conventional
Conventional
with filters
Conventional
0
0
0
0
.79
.73
.70
.66
10
15
34
7.7
0
0
0
0
.147
.10
.041
.21
13
10
19
6
.2
.8
460
500
140
1100
(29)
(31)
(8.9)
(69)
_
* Based on MLSS, not MLVSS
** Values in parantheses are equivalent loadings in Ib BOD5/day/1000 ft3.
• SINGLE - STAGE AERATION
A TWO-STAGE AERATION
10 2O 30 40
MCRT-DAYS
50
6O
7O
Figure 20. Influence of mean cell residence time on sludge production.
; The correlation between F/M and sludge production is presented in Figure
21. Routine MLVSS data was not collected at most facilities so the F/M pre-
sented is based on kg BOD5/day/kg MLSS. The linear line of best fit between
73
-------
F/M and sludge production slopes upwhrd indicating a greater sludge production
ratio at a higher F/M. However, very little difference in sludge production
is indicated over the range of F/M values studied. Furthermore, the correla-
tion coefficient was only 0.10 indicating no significant correlation between
the F/M and sludge production ratios.
• Ra0.10
• SINGLE-STAGE AERATION
A TWO-STAGE AERATION
0.05
0.10
0.15
0.20
0.25
0.30
F/M
Figure 21. Influence of food to microorganisms ratio on sludge production.
Sludge production ratio versus |the WWDT^ is shown in Figure 22. Values
J:pr WWDTft were determined by dividing the total aeration volume by the
average daily flow. The linear relationship between WWDT^ and sludge pro-
duction slopes in the expected direction. However, the poor correlation coef-
ficient indicates an insignificant correlation between these values.
1
o a
P in
li
is
£ »
3 S
Is
ii
*».».
yj CA
•g yy
S E
•*•{* (9
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
ai
0.0
! ' . .
** '
A
• [ «
. •! Rx-0.19
T ~9 — — —
• • i •
; ••
[
.
• SINGLE-STAGE AERATION
A TWO -STAGE AERATION
1
1 1 III t
0 5 10 15 20 25 30 3
WWDTA - HR
Figure 22. Influence of wastewater detention time in the aerator on
sludge| production.
I .
Sludge production ratios versus aeration basin organic loading are
presented in Figure 23. The linear correlation coefficient of only 0.07
indicates almost no correlation exisps.
74
-------
160
GM BODS/ M3/DAY
320 480 640
800
960
1120
•» R=0.07
• SINGLE-STAGE AERATION
A TWO-STAGE AERATION
1O 2O 30 40 50
LB BOD5 /1,000 FT3/ DAY
60
70
Figure 23. Influence of aeration basin organic loading on sludge production.
The most important observation from the attempts to correlate sludge pro-
duction with common operating parameters was that sludge production was not
significantly less for the variety of plants studied. However, in practice
typical design sludge yield values vary from 0.65 kg of TSS produced per kg of
BODg removed for conventionally loaded activated sludge plant to 0.15 kg of
TSS produced per kg of BOD5 removed for extended aeration plants (8,9).
Actual sludge production documented indicates that all facilities would have
undersized sludge handling capability if designed with these typical values.
It was concluded that a sludge production ratio of approximately 0.75 kg of
TSS produced per pound of BOD5 removed represents a more realistic value for
providing adequate sludge handling facilities.
Required Sludge Wasting Capacity
Wasting variations were evaluated; to determine the effect on wasting
requirements. This information is plotted in Figure 24, indicating how
short-term wasting'requirements can vary by as much as 100 percent of the
long-term average. Obviously, sludge treatment facilities must be capable of
handling the short-term peaks as well as the long-term average if good
activated sludge mass control and high quality effluent are to be maintained.
Therefore, realistic sludge production estimates form only the basis for
providing adequate sludge wasting capability.
Many of the performance-limiting factors identified related to the gen-
eral area of sludge production and wasting requirements. Evaluation has shown
that actual sludge production is several times greater than the amount common-
ly projected for small activated sludge facilities. As such, adequate sludge
handling capability must be-provided before optimum performance of many exist-
ing wastewater treatment plants can be achieved.
75
-------
8000
7000
6000
5000
4000
3OOO
2000
1000
fUJfTOK'
, , . I , , , I , . ,!l , , , I ,
4000
3500
3000
2500
2000
•BOO
1000
500
12 16 20 24
: WEEKS
32
Figure 24. Variations in sludge wasted to maintain process control.
AEROBIC DIGESTERS
Aerobic digesters were used in fourteen of 36 of the activated sludge
plants in which a comprehensive evaluation was completed. In the other 22
activated sludge plants, eleven had no sludge treatment, four had anaerobic
digesters, and seven had other. type[s of sludge treatment. Aerobic digestion
was not used at any of the fixed film facilities evaluated. During the pro-
ject many improper applications of aerobic digester design and operation were
noted. '
The performance-limiting factor of improper operator application of con-
cepts and testing to process contrbl was very apparent in aerobic digester
operation. The fundamental concept:that sludge solids wasted to the digester
should not be returned to the wastewater treatment process was frequenly vio-
lated at facilities evaluated. Another common misconception was that in order
for an aerobic digester to work, it must be loaded at a controlled rate. To
address this misconception, the relationship between the aerobic digester
sludge treatment process and activated sludge wastewater treatment process
must be established. To achieve loptimum wastewater effluent quality, the
amount of sludge wasted should be b[ased on the requirements of the activated
sludge process, and not on the organic loading considerations of the aerobic
digester. Misconceptions concerning these points dramatically affected the
operation and performance of aerobic digesters. Problem areas noted were
improper use of digesters, inadequate supernating capabilities and practices,
and insufficient digester size. ;
Flagrant misuse of aerobic digesters was observed most often in activated
sludge package plants incorporating the contact stabilization mode of
76
-------
operation. These facilities were typically designed so that return activated
sludge from the bottom of the clarifier was air-lifted to a reaeration basin.
Sludge wasting was accomplished by either directing the return sludge flow to
the aerobic digester or by air-lifting sludge from the reaeration basin to the
digester. Within the digester an automatic supernating device was constructed
to recycle supernatant back to the reaeration basin for treatment. A schema-
tic diagram of a typical automatic supernating device is shown in Figure 25.
Typically, the automatic supernating deyice was ineffective and digester
solids were recycled into the activated sludge process. Consequently, sludge
was only removed from the system when hauled to ultimate disposal (typically
land application). Unfortunately, sludge was normally lost over the final
clarifier weirs in the plant effluent. Even when excessive solids loss of
this nature was not occurring, a turbid, poor quality effluent was discharged
because the activated sludge process was not properly controlled. At facili-
ties where this type of digester operation was encountered, use of the contin-
uous supernating devices was stopped, and the digester was operated on a batch
basis. To convert to a batch mode of operation, draw-off lines or a portable
pump were used to remove clear supernatant after the air supply to the digeser
was shut-off and the digester contents were allowed to settle. Supernating
capability which had adjustable draw-off levels was most desirable.
.RAW WASTE
SLUDGE
SUPERNATANT,
RETURN LINE^I
Figure 25. Automatic supernating device.
The batch operation approach allowed the operator to reserve capacity in
the digester so that activated sludge wasting could be completed as necessary.
When clear supernatant could not be obtained and removed to achieve this capa-
city the operator was instructed to remove sludge from the digester to the
ultimate sludge disposal site. Another advantage of. the batch operation
approach was that the operator was able to monitor the quality of supernatant
to insure that excessive quantities of digested sludge solids were not
recycled to the activated sludge process.
At some facilities, problems were encountered when attempting to operate
the digester in a batch mode of operation because the digester walls were not
77
-------
designed with sufficient structural' integrity. Many of these plant were built
with all unit processes (i.e. aeration basin,clarifier and digester) contained
in a large concrete structure which had steel walls to separate the basins.
These walls were not designed to iallow significant liquid level variations
between adjacent basins. When onejunit required dewatering, the liquid level
in all units had to be lowered simultaneously. In most of these facilities
the difference between liquid levels in adjacent basins could not be greater
than about one meter (three feet) jwithout risking structural failure. This
constraint limited the effectiveness of batch digester operation since an
increased frequency of supernatingi was required which resulted in increased
operational requirements and decreased sludge digestion time.
i
i
In many facilities the aerob'ic digesters were undersized and caused
increased operational requirements Jand considertions. The small sized digest-
ers were felt to be a result of inadequate sludge production values used in
the original design calucations (see. previous section). The primary problem
with undersized digesters was that increased frequency of supernating was
required and decreased sludge digestion occurred. In a few cases limited
digestion resulted and partially digested sludge that would not settle was
produced. In these facilities, increased resources to transport the sludge to
ultimate disposal sites was necessajry.
I
Although sludge digestion was less than desired because of short detention
time in the digester, this operational approach was considered a better solu-
tion than allowing large quantities of sludge to be discharged to the receiv-
ing stream. !
In general, aerobic ,digesters were not being effectively utilized and
were found to be contributing to
the plant performance problem. In many
instances it was not understood that activated sludge solids wasted to the
digester are not to be returned to ithe wastewater treatment processes. Addi-
tionally, it was not understood thkt aerobic digester performance should not
dictate the amount of sludge wasted! from the wastewater treatment process. As
such the aerobic digester must be viewed as an intermediary unit between the
activated sludge process and the ultimate disposal system. If the digester
does not have the required capacity to serve this purpose, ultimate sludge
disposal capabilities must be expanded in order to maintain high effluent
quality from the wastewater treatment process. Additionally, adequate aerobic
digester capacity is generally not [available to handle the sludge produced by
wastewater treatment processes. Until sludge treatment facilities are design-
ed based on realistic values for sludge production plant performance will con-
tinue to be adversely affected.
PLANT REFERENCE LITERATURE
j
Numerous technical publications and periodicals are published for waste-
water treatment personnel by government agencies, training schools and techni-
cal societies. The availability and useage of this material by treatment
plant operators has not been established. The lack of technical literature at
treatment facilities has been thought to be a cause of poor facility perform-
ance. This is evidenced by the emphasis in recent years by regulatory and/or
78
-------
reviewing agencies to make available plant specific operator oriented litera-
ture (i.e. operation and maintenance manuals) at newly constructed wastewater
treatment facilities.
' *. • - •
A special study was implemented to determine the type of reference mater-
ial available and the level of usage of this material. A standard form list-
ing selected references was used to obtain information on availability of a
variety of literature sources. Space was provided on the form for an evalua-
tion of the level of usage. Reference usage was assigned points using the
following: 0) available but not used, 1) read through once, 2) used occasion-
ally, or 3) used regularly. A compilation of the available literature and its
usage at 48 facilities surveyed is shown in Table 18. This evaluation was
initiated during Phase II, and the 48 facilities shown represent facilities
where either site visits or comprehensive evaluations were conducted. The
reference items were divided by topic among four categories; operation and
maintenance, laboratory, management and periodicals.
The reference items were ranked according to the total number of usage
point received. Usage was that by the chief plant operator or the person in
charge of making the process control decisions. The ranking of each reference
item within the four broad topic categories is also shown in Table 18.
Operation and Maintenance References
Twenty-four reference items are included in the operation and maintenance
category. These items varied from general (i.-e., Operation of Wastewater
Treatment Plants) to specific (i.e., the plant specific Operation and Mainten-
ance Manual). The reference with the most usage points was the plant Opera-
tion and Maintenance manual. Despite the regular usage of plant specific
0 & M manuals only about 30 percent of the surveyed facilities were meeting
secondary effluent standards. This data does not indicate that information
provided by a plant 0 & M manual is inadequte nor unnecessary. However, it
does indicate that an 0 & M manual may be limited in its ability to provide a
basis for the operator to improve plant performance. s
The second highest ranking factor limiting plant performance identified
in this research was sewage treatment understanding. The high ranking of
references such as: the Sacramento Course, New York Manual, Texas Manual,
Studybook for Wastewater Operator Certification and the Operation of Waste-
water Treatment Plants support this research finding. These manuals cover a
wide range of basic wastewater topics and their use indicates that the opera-
tors recognize the need for more basic understanding of the sytems they are
asked to control. Plant operators also indicated that these sources provided
a good basis of study for preparing to take operator certification exams. The
application of these reference items to plant performance problems is somewhat
limited because of their general nature. The first literature source that was
indicated by the operators to be used to aid in addressing a specific plant
operational problem was the Operations Manual Anaerobic Sludge Digestion.
79
-------
TABLE 18. AVAILABILITY AND USAGE OF PLANT REFERENCE LITERATURE
Category
Rank
Reference i
No. of Plants
Reference Level of -Usage*
Available 012 3 Total Pts
A. Operation and
Maintenance
References
1 Plant 0 & M Manual 45
2 New York Manual j -36
3 Sacramento Course 29
4 Operation of Wast/ewater
Treatment Plants-IwPCF
MOP 5 i 29
•5 Texas Manual [ 21
I
6 Studybook for Wastewater
Operator Certification-
WPCF ' 21
I
7 Operations Manual
Anaerobic Sludge [Digestion
(EPA 430/9-76-001) 18
8 Literature from Local
and/or State Training
Schools • 9
9 Package Treatment Plants,
Operations Manual
(EPA 430/9-77-005) 10
10 Aeration in Wastewater
Treatment WPCF M6p 3 11
11 Procedural Manual for
Evaluating the Performance
of Wastewater Treatment
Plants - EPA ; 8
12 Operational Control Pro-
cedures for the Activated
Sludge Process (^est) 6
13 A Planned Maintenance
Management System for
Municipal Wastewater
Treatment PlantsljEPA-600/
2-73-004) ! 5
14 Process Control ijlanual
for Aerobic Biological
Wastewater Treatment
Facilities (EPA-430/
9-77-006 [ 9
15 Start-Up of Municipal
Wastewater Treatment
Facilities (EPA-430/
9-74-008)
16 Sludge Dewatering-WPCF
MOP 20
5 1 21 18 97
3 3 16 14 77
0 2 16 11 67
2 8 8 11 57
3198 43
3396
5553
39
33
0117. 24
1252 '18
1541 16
2132 13 .
1 113 12
1032 12
2430 10
2221 9
0411' 9
(Continued)
80
-------
TABLE 18. (CONTINUED)
Category
Rank
Reference
No. of Plants
Reference Level of Usage*
Available 0 123 Total Pts_
B. Laboratory
References
C. Management
References
17 Maintenance Management
Systems for Municipal
Wastewater Facilities
(EPA-430/9-74-004)
18 Chlorination of Waste-
Water-WPCF MOP 4
19 Technical Books
20 Utilization of Municipal
Wastewater Sludge-WPCF
MOP 2
21 Paints and Protective
Coatings for Wastewater
Treatment Facilities-
WPCF MOP 17
22 Sludge Treatment and
Disposal-EPA Technology
Transfer
23 Units of Expression for
Wastewater Treatment-
WPCF MOP 6
24 Upgrading Existing Waste-
Water Treatment Plants
EPA Technology Transfer
Standard Methods for
Examination of Water and
Wastewater-APHA,AWWA,WPCF
Simplified Laboratory
Procedures for Wastewater
Examination-WPCF MOP 18
Analytical Quality Control
EPA Technology Transfer
Methods for Chemical
Analysis of Water and
Wastes-EPA Technology
Transfer
Estimating Laboratory
Needs for Municipal
Wastewater Treatment
Facilities (EPA)
Monitoring Industrial
Wastewater-EPA Technology
Transfer
1 Safety in Wastewater Works
WPCF MOP 1
5 0040
7 3130
3 0111
5 2210
3 0 210
2 0110
1 0100
1 0 100
43 4 5 16 18
33 . 3 5 16 9
3 0012
5 1121
4 1-021
4 0211
91
64
14
1,48 1
23
(Continued)
81
-------
TABLE 18. (CONTINUED)
I No. of Plants
Reference Level of Usage*
Category Rank Reference Available 0 123 Total Pts
2
3
4
5
6
7
8
9
D. Periodical
Publications
1.
2
3
4
5
6
7
8
Regulation of Sewer Use-
WPCF MOP 3 12 6 1 5 0
Emergency Planning for
Municipal Wastewater
Treatment Facilities(EPA-
430/9-74-013) • 4 0031
Estimating Staffing for
Municipal Wastewater
Treatment Facilities(EPA) 3 1020
Safety Practices for Water
Utilities - AWWA M3 1 0010
Tailgate Safety Lectures-
AWWA M16 . ; 1 0-010
Uniform System of Accounts
for Wastewater Utilities-
WPCF MOP 10 2 0200
Financing and Charges for
Wastewater Systems -
APWA, ASCE, WPCF 1 0100
Public Relations for Water
Pollution Control - WPCF 2 ' 1 100
Water Pollution Control
Federation Highlights 23 1886
Journal Water Pollution
Control Federation 25 3 8 12 2
Water and Wastes
Engineering 26 3 13 6 4
Public Works . 22 1 10 10 1
\
Regulatory Agency V
Newsletter 6 0 5 • 0 1
American City and
County 2 0020
Engineering News— Record 1 0010
Water and Sewage Works 1 0100
12
9
4
2
2
2
1
1
42
.
38
37
33
8
4
2
1
* 0 » Available but not used.
1 » Read through once.
2 » Used Occasionally.
3 » Used regularly.
82
-------
Laboratory References
Six items were included in the laboratory category. Standard Methods for
the Examination of Water and Wastewater,was utilized most often for conducting
laboratory analyses, and Simplified Laboratory Procedures for Wastewater Exam-
ination was the second most used reference. The manual, Methods for Chemical
Analysis of Water and Wastes, did not have widespread use among the facilities
surveyed. Other references, which were used on a less frequent basis, dealt
with quality control, industrial monitoring and laboratory needs.
Management References
Nine different reference items were included in the plant management
category. Safety in Wastewater Works was the most utilized reference followed
by Regulation of Sewer Use. Usage of these references was mostly on a read
through once or used occasionally basis. Other literature in this category
was available at only a few of the facilities surveyed.
Periodical Publications
Periodical publications were a common source of technical information for
plant personnel. The Water Pollution Control Federation Highlights received
the highest ranking in this category. This publication is specifically ori-
ented toward plant operations personnel. Other periodicals that were ranked
high among the plant personnel include the Journal Water Pollution Control
Federation, Water and Wastes Engineering, and Public Works.
Relationship Between Reference Material and Plant Performance
/
An evaluation was conducted to determine i£ a relationship existed be-
tween references utilized by plant personnel and a facilities' ability to meet
secondary treatment standards. Table 19 shows the total usage points per
plant for the reference materials evaluated. Plants meeting standards on a
consistent basis are denoted. A definite trend does not exist between high
usage of references (high total points) . and plant performance. However, the
average points, with respect to reference usage, for those plants meeting
standards was 25, while the average points for those plant not meeting stand-
ards was 18. It is not known if this difference in usage is significant, but
the trend of better performance associated with increased use of references
indicated by this data is encouraging.
Overall conclusions on the use of references and plant performance were
difficult to develop with the data available from this analysis. However, it
was concluded that, without additional guidance, the majority of present plant
operators cannot apply wastewater treatment concepts presented in most litera-
ture sources to the operation of their facilities.
OPERATOR TIME AND TASKS
Plant staffing is an important consideration in achieving the desired
performance in any wastewater treatment facility. However, adequate manpower
83
-------
TABLE 19. RELATIONSHIP OF REFERENCE MATERIAL USAGE AND PLANT PERFORMANCE
1
Level of Usage
Plant Identity 0 1 2 1 3
063
073
088
067
040
072
014
097
024
092
068
029
070
047
093
064
090
094
034
013
096
021 -
061
027
084
048
060
028
041
032
085
036
052
015
035
002
083
039
086
025
079
065
055
022
077
062
050
069
0
2
0
2
0
2
0
1
0
0
3
0
1
0
0
0
1
3
1
0
1
0
0
3
1
1
2
3
1
0
1
1
5
0
2
1
0
2
2
2
0
4
0
4
0
1
1
10
0
4
2
5
0
2
0
1
0
4
4
0
8
1
3
8
2
6
10
4
3
2
3
3
0
5
4
4
0
3
3
2
0
2
5
0
0
1
2
5
2
1
3
0
0
2
0
0
6
15
6
11
6
9
5
2
6
7
8
11
10
7
1
7
2
6
7
15
6
12
4
8
5
8
8
6
4
3
2
0
4
7
1
6
2
0
5 3
3 : 4 '
8 1
2 4
8 0
4 3
4, 1
4 1
2 2
7 0
5 0
0. 3
2 2
4 1
3 1
1; 1
0. 3
0 3
1' 2
2 1
2 0
3: o
'31 0
2! 0
31 0
3i 0
Ol 1
2 0
0 1
Total Pts.
57
52
50
39
36
- 35
34
31
30
30
' 29
28
28
27
26
25
24
24
24
23
21
21
19
19
17
16
15
14
14
13
12
12
11
11
10 *
9
9
9
9
9
8
7
7
6
6
5
4
3
Secondary
Standards
Met
yes .
no
yes
yes
no
yes
no
no
no
yes
no
no
yes
no
no
yes
no
no
no
no
no
yes
no
no
yes
no
no
no
yes
no
no
yes
yes
no
yes
no
no
no
no
no
no
no
yes
no
no
no
no
no
Type*
of
Survey
CS
SV
SV
SV
CS
SV
CS
CS
CS
CS
CS
CS
CS
CS
CS
SV
SV
SV
CS
CS
SV
CS
CS
CS
SV
CS
CS
SV
CS
CS
CS
CS
CS
es-
CS
CS .
SV
CS
CS
SV
SV
CS
CS
CS
CS
CS
CS
CS
*SV » Site Visit; CS = Comprehensive Survey
84
-------
is like adequate design, adequate testing equipment or operating budgets; it
provides one of the base level requirements from which to build a plant toward
optimum performance. Therefore, providing adequate manpower should not be
expected to produce good plant performance without proper training, a good
plant design and other essential elements. • •-
During the research project, CCP's were demonstrated in selected facili-
ties. An evaluation was made of the effect of the CCP on operator time and
tasks for two of these facilities. The objective was to document changes in
time and tasks and to relate these changes to operator activities in other
facilities. The facilities selected were a 570 cu m/day (0.15 mgd) contact
stabilization, package-type plant and a 3800 cu m/day (1.0 mgd) extended aera-
tion activated sludge plant. These facilities, in addition to being suitable
for implementation of limited CCP's, were representative of a large number of
other plants evaluated in terms of size, type and operator coverage.
Plant 065
Plant 065, a small contact stabilization activated sludge plant was oper-
ated on a part-time basis by one city employee. The operator was also assign-
ed duties associated with other city utilities. The operator was certified'
and attended operator seminars periodically. Before the CCP was implemented,
the operator was not properly applying process controls nor was he aware of
which operational adjustments or tasks most significantly influenced plant
performance. Solids loss occurred repeatedly resulting in frequent violations
of NPDES permit standards. The CCP was implemented over a 12 month period.
The operator's process control capability was improved considerably as evi-
denced by improved sludge characteristics and associated improved effluent
quality. The overall effluent quality averaged less than 30 mg/1 for 3005
and TSS, but the monthly averages exceeded secondary treatment standards dur-
ing three months of the year.
Operator time spent at various tasks before and after the CCP are pre-
sented in Table 20. As shown, time spent on the categories of administration,
staff development, maintenance and inspection, and compliance monitoring was
not effected by the CCP. Time and tasks expended for process control were
affected by implementation of the CCP. The Process Control category includes
all tasks associated with activated sludge process control testing, decision
making and implementation. Before the CCP was initiated, approximately 9 1/2
hours per week were devoted to these tasks. After the CCP, about 17 1/2 hours
per week were required. Increased,time was required for operational testing
to develop and maintain the desired sludge characteristics. The main control
of sludge character implemented was adequate sludge mass control, which
required increased time for the utilization of the available aerobic digester
and for removing the digester contents to the land application1 site. Total
Plant operating time requirements increased from 25 hours per week to 33 hours
per week.
Plant 086
Plant 086, a 3800 cu m/day (1.0 mgdj) extended aeration plant was operated
by a superintendent and operator at the initiation of the CCP. Shortly before
85
-------
TABLE 20. OPERATOR TIME AND TASKS AT PLANT 065
Before CCP
hr/wk
After CCP
hr/wk
ADMINISTRATION
Coordination, scheduling
STAFF DEVELOPMENT
2.5
Seminars, literature review
MAINTENANCE & INSPECTION
Preventive and emergency maintenance, rag re-
moval, weekend inspections, yards, housekeeping
COMPLIANCE MONITORING ;
Tests, reports
PROCESS CONTROL
Tests, calculations, graphs return adjust-
ments, wasting, sludge hauling, supernating
i
TOTAL PLANT WORK
9.5
25*
2.5
17.5
33*
*The balance of the operator's time' was spent on assigned duties associated
with other city utilities.
the research, the plant had been operated by the superintendent and by a lab-
oratory technician. The laboratory technician had quit and the operator was
hired. During the course of the CCP, a third person was hired to fill the
position of laboratory technician lunder the CETA program. Both before and
after the CCP the superintendent and operator worked part time maintaining the
wastewater collection system. \
i
The superintendent of Plant |086 was certified but had quit attending
short-courses because he could noj: find satisfactory help in setting up a
sludge wasting program. Before the CCP, sludge wasting was completed only
periodically. For several months before the CCP, wasting had been discontinu-
ed altogether, resulting in several permit violations. Daily sludge wasting
was implemented as part of a complete process control program and good efflu-
ent quality was achieved. Additionally, the superintendent's process control
capabilities and understanding were improved. Effluent qualilty averaged 8
mg/1 for BOD5 and 4 mg/1 for TSS fojr the eight months of the CCP.
Operator time spent at various tasks before and after the CCP are
presented in Table 21. The majority of increased time was required, for
expanded process control activities. To support the need for additional time
i
86
-------
TABLE 21. OPERATOR TIME AND TASKS AT PLANT 086
Before CCP
hr/wk
After CCP
hr/wk
ADMINISTRATION
Coordination with,city, scheduling
filing, visitors, coffee 17 17
STAFF DEVELOPMENT
Seminars, certification study, literature review 2 - 8
MAINTENANCE & INSPECTION
Preventive and emergency maintenance, yards,
inspection, grit & rag removal, housekeeping 36 35
COMPLIANCE MONITORING
Tests, reports 6 6
PROCESS CONTROL
Tests, calculations, graphs, return adjust-
ments, discussions, wasting, supernating 6 32^
TOTAL PLANT WORK 67 98
NON-PLANT WORK BY OPERATORS
Lift stations, lines, taps
Miscellaneous city work , 13 28
TOTAL 80 126
a person for line maintenance was hired. Available time in excess of that
used for needed line work and increased process control was used for staff
development (i.e., studying for certification).
Discussion
Operator time and tasks were evaluated for two facilities; in both the
need for additional operator time for process control was documented. In the
smaller facility, a 32 percent increase in total operator time was needed to
achieve an acceptable level of process control. However, this increase repre-
sented eight hours per week. In the larger facility the need for increased
manpower for process control required that a third operator be hired. The
result was a 46 percent increase in manpower used at the plant. Despite this
87.
-------
large percentage increase, the difference in operator time required between
virtually no process control and excellent process control was 26 hours per
week.
Large percentage increases in| operator requirements were documented.
Yet, for these relatively small facilities the percentage increases represent
rather minor increases in time on a per week basis. It was concluded that
relatively small amounts of operator time spent on meaningful process control
activities could lead to dramatic improvement in plant performance. Although
not, evaluated, it was felt that for larger facilities no additional staff
would be necessary. A shift in priorities would allow these operators to
address process needs.
EFFECTS OF TOXICS ON PLANT PERFORMANCE ,
I
The term toxics is used to describe a multitude of compounds and elements
which are present in some wastewaters in concentrations large enough to inhib-
it biological wastewater treatment processes. Toxics found in publicly owned
wastewater collection systems are normally associated with industrial waste-
waters. One of the plant selection briteria was that facilities treat primar-
ily domestic wastes. As a result, the majority of plants.studied did not have
problems with toxic substances. Five of the 50 facilities studied had docu-
mented occasional severe problems with toxics. Some detrimental effects of
lower levels of toxic elements were Isuspected but not documented at four addi-
tional plants.
The survey facilities affected by toxics are identified in Table 22.
Trickling filter plants 035 and 095 reportedly received slug discharges of
toxics sufficient to "kill off" a large fraction of ,the biomass on the fil-
ters. Plant 035 reportedly received sufficient acid to render a toxic pH at
the plant. Plant 095 did not identify the compound, but received periodic
slugs of a yellow precipitate which reportedly hindered performance.
Plants 065 and 077 were both small contact stabilization activated sludge
plants which received periodic slugs of petroleum products in the raw waste-
water. At Plant 077 the problem was found to be diesel fuel from the city
power plant.
Plant 065 . ,
Plant 065 is a small contact stabilization activated sludge plant which
was the subject of a CCP demonstration (Section 7). At plant 065, a railroad
tank car washing operation was highly suspected as the source of toxic chemi-
cals, but the probable source was [later located at the school bus garage.
Crankcase oil from the buses was drained directly to the sanitary sewer.
The periodic presence of an inhibitory compound was apparent in- the
results from the process control testing initiated as part of the CCP. When
inhibitory slugs of oil were received, the sludge compacted significantly
greater in the centrifuge analysis indicating an apparent loss of sludge from
the system. A drop of between 25 and 50 percent of the total sludge mass in
: 88
-------
TABLE 22.. IMPACT OF TOXIC SUBSTANCES ON 50 COMPREHENSIVE SURVEY FACILITIES
Plant
No.
002
007
012
013
014
015
019
020
021
022
024
026
027
028
029
032
034
035
036
038
039
040
041
047
048
050
051
052
053
055
060
061
062
063
065
066
068
069
070
074
075
077
080
082
085
086
092
093
095
097
Date
1975
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1976
1978
1976
1976
1977
1976
1976
1977
1977
1977
1977
1977
1977
1977
1977
1977
1977
1977
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
Plant
Actual Flow
Type cu m/day
ASEA
ODEA
TF/CS
AS
AS
T3?
ASEA
ASEA
ODEA
ASEA
ABF
ASEA
AS
ASCS
AS
TF
TF
TF
TF
AS
ODEA
RBC
TF
ASEA
AS
ASEA
ASEA
ASEA
ASEA
ASEA
ABF
ASCS
ODEA
AS
ASCS
AS(2)
AS
TF
TF
AS
AS
AS
AS
ASCS/TF
ODAS
ASEA
AS
RBC
TF '
ASCS
1,628
155
30,660
1,892
3,785
6,434
132
26
2,233
45
18,550
568
20,820
568
5,185
833
20,820
20,060
6,056
11,880
795
1,438
492
189
1,287
643
795
170
416
1,136
1,855
643
757
2,650
492
2,687
20,440
303
4,164
1,136
21,950
908
946
314
3,179
1,817
11,910
8,327
4,542 .
3,179
ingd**
0.43
0.041
8.1
0.5
1.0
1.7
0.035
0.007
0.59
0.012
4.9
0.15
5.5
0.15
1.37
0.22
5.5
5.3
1.6
3-14
0.21
0.38
0.13
0.05
0.34
0.17
0.21
0.045
0.11
0.30
0.49
0.17
0.20
0.7
0.13
0.71
5.4
0.08
1.10
0.30
5.8
0.24
0.25
0.083
0.84
0.48
3.12
2.2
2.1
0.84
TOTAL
, Ho Problem
Z Design Problem Suspected
54
59
68
63
50
47
54
28
66
80
69
30
55
60
78
50
68
98
87
70
51
60
33
80
89
96
75
60
68
52
47
, 34
59
47
87
' 76
98
.114
101
36
64
78
60
69
86
48
57
44
48
84
FACILITIES
X
X
X
X
X
X
X
X
X
X
X
X
X x
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
41 4
Problem
Documented
X
X
X
X
X
5
the plant was indicated. Immediate changes in activated sludge characteris-
tics also resulted. The sludge exhibited faster settling and turbid superna-
tant characteristics. The period during which slugs of oil was received coin-
cided exactly with a significant reduction in plant performance. For the
5-month period prior to receiving the oil, effluent BOD5 and TSS averaged 20
mg/1 and 8 mg/1, respectively. For the 5-month period during which the oil
slugs were received, effluent quality averaged 54 mg/1 for BOD5 and 24 mg/1
for TSS.
89
-------
Lack of adequate process control can often be the cause of poor plant
performance. In fact, it has been< observed that toxic substances are blamed
for this less than optimum condition. However, in the case of Plant 065, the
slugs of oil were felt to be the singular most direct cause of poor perform-
ance since good process control had been established for a 5-month period
prior to the plant receiving oily wastes.
The long time associated with jdeveloping desirable activatd sludge char-
acteristics was documented during phase I (4). This long time requirement
helps explain why a relatively minor yet periodic problem with toxic substan-
ces can create a long-term continuous performance problem. In Plant 065 two
to four weeks of time was available between each slug of oil. This was not
sufficient for the sludge quality to recover. As a result, poor performance
occurred over a long period of time!. This problem will persist until the oil
source is removed. i
Plant 086
I •
Plant 086 is a 3800 cu m/day (1 mgd) activated sludge plant which was the
subject of a CCP demonstration (Section 7). The plant superintendent reported
several instances of a "tomato juice smell" at the plant headworks. Several
of these instances were recorded ! without apparent detrimental effects on
effluent quality. After several months, another typical "tomato juice smell"
was detected along with a yellow precipitate in the plant influent. In sever-
al days the mixed liquor appeared gray and the effluent was highly turbid.
™ The sludge inventory in the pl|ant an3T~the sludge wasted to maintain that
inventory are presented in Figure 26. The "tomato juice smell" and gray mixed
liquor occurred during Week 4. | As
radically the next two weeks . ; In
response to the loss of sludge growth,
wasting was reduced to a minimum
starting with Week 6. By adjusting
the wasting to a level below the
decreased sludge growth rate, the
sludge inventory was gradually return-
ed to the desired level. Sludge pro-
duction remained at a minimum for a
seven-week period (weeks 5 through
11), before activity in the sludge
returned and near normal sludge pro-
duction was experienced. The duration
of this recovery period indicates the
long time period associated with bjLo-
logical system response.
shown, the sludge inventory dropped
Effluent quality during the
(13-week) period is presented in Fig-
ure 27. Effluent BOD5 and TSS
averaged 9.0 mg/1 and 8.1 mg/1
respectively, for the first six
10,000
8,000
«,ooo
4,000-
2,000-
o
I-
Ul
in
8 9 10 ,11 12 13
WEEKS
Figure 26. Impact of toxics on
sludge activity at Plant 086.
90
-------
weeks. Effluent quality degraded
•approximately three weeks after the
major slug load of toxics was receiv-
•ed at the plant. No permit viola-
tions were experienced as effluent
peaked at 27 mg/1.
50
At this writing, a metal plating
industry was suspected to be the
source of the toxics in the plant in-
fluent and samples had been obtained
for analysis. Low levels of chromium,
zinc and cyanide were found, but con-
clusive evidence concerning the exact
amounts and concentrations which
caused the plant operations problem
was not available.
Discussion
t 2 3 4 5 8 7 8 9 10 11 12 13
WEEKS
Figure 27. Impact of toxics on
effluent quality at Plant 086.
The effects of toxic substances
on the performance of biological
wastewater treatment processes were
documented at two facilities. Peri-
odic slug loads of oil were the sus-
pected cause of degraded effluent
quality in Plant 065. Due to the in-
herent long time necessary for activated sludge characteristics to recover,
the periodic slug loads resulted in consistent, long-term degraded effluent
quality.
Plant 086 was an underloaded extended aeration activated sludge plant.
Toxics substances received at this plant resulted in a long-term (7-week) re-
duction in sludge activity, but only caused minor problems with plant efflu-
ent quality. Optimum sludge characteristics maintained before the toxic sub-
stances were received and quick operational response to changed wasting
requirements were instrumental in minimizing the effect on plant performance.
A larger slug dose may have caused considerably more severe problems.
Toxics were not identified as an overall major performance-limiting fac-
tor for the fifty plants studied. However, plants with known toxicity prob-
lems were excluded from study. In evaluating the effect of toxic substances
on biological processes, it should be recognized that the symptoms of a tox-
icity problem are often similar to problems associated with improper process
control. Toxic problems were identified at two facilities where improved pro-
cess control had been established. Since improved process control was attain-
ed first, the true impact of the toxicity problems was felt to be demonstrat-
ed. It was concluded that when a true toxicity problem is indicated, finding
and eliminating the source of the substance should receive a high priority.
91
-------
REFERENCES
Gilbert, Walter G., "Relation |of Operation and Maintenance to Treatment
Plant Efficiency," Journal Water Pollution Control Federation, 48, 1822
(1976). —
2. "Continuing Need for Improved Operation and Maintenance of Municipal
Waste Treatment," Report to the Congress by the Comptroller General of
the United States, Washington, D.C., (April 11, 1977).
3. Gannett, Fleming, Cordry and Carpenter, Consulting Engineers, Harrisburg,
Pennsylvania. Evaluation of Operation and Maintenance Factors Limiting
Biological WastewaterTreatmentPlantPerformance,ReportNo.
EPA-600/2-79-087, July 1979.
4. Hegg, B.A., K.L. Rakness and J.R. Schultz. A Demonstrated Approach for
Improving Performance and Reliability of Biological Wastewater Treatment
Plants.M &T]Inc.,Consulting Engineers, FortCollins,Colorado,
Report No. EPA-600/2-79-035, June 1979.
i ' '
5. Hegg, B.A., K.L. Rakness and J.R. Schultz. Evaluation of Operation and
Maintenance Factors Limiting Municipal Wastewater Treatment Plant Per-
formance. M & I, Inc., Consulting Engineers, Fort Collins, Colorado,
Report No. EPA-600/2-79-034, June 1979.
6. "WPCF's Role in Solving 0 & M Problems," Deeds and Data, Water Pollution
Control Federation, Vol. 15, Ncj. 6, June 1978.
7. "Operations and Maintenance: : Problem/Solution Workshop Held," High-
lights, Water Pollution Control Federation, Vol. 15, No. 7, July 1978.
8. Goodman, B.L. and Foster, J.W.|, "Notes on Activated Sludge," Smith and
Loveless Corporation, Division of Union Tank Car Company, Lenexa, Kansas,
Second Edition (1969).
9. Stewart, Dr. Mervin J., "Activated Sludge Process Variations - The Com-
plete Spectrum," Water & Sewage, Works, Volume III, No. 4 (April, 1964).
92
-------
APPENDIX A
LOCATION'OF FACILITIES
AND .
TYPE OF EVALUATION CONDUCTED
TREATMENT FACILITY LOCATION
STATE
Colorado
Iowa
Montana
Nebraska
SITE VISIT
Kittredge
Colorado Springs
Empire
Georgetown
Vail
Brush
Victor
Cripple Creek
Clarinda
Shenandoah
Eldora
Iowa Falls
Os age
Tama
Mason City
Oskaloosa NE
Oskaloosa SW
Ankeny
Butte
Kalispell
Big Fork
Yellow Bay Biological Sta.
Harlem
Fremont
Scribner
Norfolk
Platte Center
Waco
Sutton
COMPREHENSIVE EVALUATION
Morrison
Englewood
Snowmass Village
Aspen Metro
Fort Morgan
Elizabeth
Elbert
Berthoud
Aurora
Eaton
Bedford
Elma
Cresco
Reinbeck .
Akron
Cherokee
Marshalltown
Melbourne
Grinnell
Grimes
Hillbrook Nursing Home, Clancy
Helena
Columbia Falls
Lolo
Missoula
Havre
Chinook
Arlington
West Point
Crete
Gretna
Elkhorn
Waterloo
93
-------
APPENDIX A (Cont.)
LOCATION[OF FACILITIES '
;AND
TYPE OF EVALUATION CONDUCTED
STATE
South Dakota
Utah
Wyoming
Kansas
Missouri
TREATMENT FACILITY LOCATION
SITE VISIT
Granger Hunter District,
Salt Lake City
Laramie
Lusk
Rock Springs
Evanston
Ottawa
Gypsum
Herington
Newton
Haysville
Anthony
Newberg
Rolla
Festus/Crystal
Eureka
Saline County Sewer
Company, Fenton
Columbia Flat Branch
Warrensburg
COMPREHENSIVE EVALUATION
Chamberlain
Mobridge
Cottonwood Dist., Salt Lake City
So. Davis N., Salt Lake City
So. Davis S., Salt Lake City
South Cheyenne
Cheyenne Dry Creek
Lawrence
Osage City
Hillsboro
Colwich
Bolivar
Marshfield
St. Charles MO R.
Kirkesville
Sedalla
Belton
94
-------
APPENDIX B
INFORMATION SHEETS FOR SITE VISITS AND COMPREHENSIVE SURVEYS
The forms in this appendix were completed for each wastewater treatment
facility where a survey was conducted. The site visit form was completed to
provide general information about the treatment facility. The comprehensive
evaluation forms were used to provide detailed information in the broad areas
of plant administration, maintenance, design and operation.
95
-------
APPENDIX B (Cont.)
SITE VISIT FORM
Operator
Person to Call for Information
Telephone No.
Type Plant
Year Built
Design Flow _
Present Flow
I/I Problems
Industrial Loads
Separate Sewers
Population Served
Receiving Stream
Water Quality Limited
Effluent Limits
Current Effluent Quality
Monitoring Tests Conducted
Operational Tests Conducted
Spare Parts Inventory
No. Operators & Certification
Plant Coverage - Weekdays
Weekends & Holidays
Preventive Maintenance Schedule
Emergency Maintenance Records
96
-------
COMPREHENSIVE EVALUATION FORMS
I. PLANT IDENTIFICATION
A. NAME AND LOCATION
NAME OF FACILITY _
TYPE OF FACILITY _
OWNBR
ADMINISTRATIVE .OFFICE: MAILING ADDRESS
TELEPHONE NO.
TREATMENT PLANT: MAILING ADDRESS .
TELEPHONE NO.
PLAHT LOCATION: LEGAL
RECEIVING STREAM AND CLASSIFICATION
RECEIVING WATER '
TRIBUTARY TO
MAJOR RIVER BASIN
_ CLASSIFICATION .
CLASSIFICATION
APPENDIX B (Cont.)
I. PLANT IDENTIFICATION (Cont.)
C. PERMIT INFORMATION
PLANT CLASSIFICATION ASSIGNED BY STATE .
DISCHARGE PEBMIT REQUIREMENTS FROM PERMIT NUMBER
DATE PERMIT ISSUED
DATE. PERMIT EXPIRES '
EFFLUENT LIMITS AND MONITORING REQUIREMENTS:
MAXIMUM
MONTHLY
AVERAGE
MAXIMUM
MEEKLY
AVERAGE
MONITORING SAMPLE
FREQUENCY TYPE
REQUIRED REQUIRED
Flow - »gd
BODj - mg/1
TSS - mg/1
Fecal Coliform -
0/100 ml
Chlorine Residual -
COMPLIANCE SCHEDULE:
OTHER TREATMENT REQUIREMENTS ANTICIPATED:
II. PLANT DESCRIPTION
III. DESIGN INFORMATION
A. PROCESS TYPE
TYPE
FLOWSHEF.T - In body of report
A. INFLUENT CHARACTERISTICS
AVERAGE DAILY FLOW: DESIGN _
CURRENT
MAXIMUM HOURLY FLOW: DEISGN
B. DESIGN FLOW
PRESENT DESIGN FLOW
_cu m/day
_mgd x 3785 =
_ragd x 3785 = .
_mgd x 3785 -
Ib x 0.454 =
C. UPGRADING AND/OR EXPANSION HISTORY - AGE
PLAHT HISTORY (Original construction, date completed, plant upgrade, date
completed)
CURRENT _
AVERAGE DAILY TSS: DESIGN
D. SERVICE AREA
NUMBER OF TAPS
GENERAL DESCRIPTION:
INFILTRATION/INFLOW:
SEASONAL VARIATION:
MAJOR INDUSTRIAL WASTES:
KNOWN INHIBITORY WASTES:
COLLECTION SYSTEM:
__cu, m/day
_cu m/day
_cu m/day
_cu m/day
97
-------
III. DESIGN INFORMATION (Cont.)
n. ran PIKYXSSKS
rUW STREAM NO.
TOIPED PIMP8
MODEL HP CAPACITY
CCtttESTSt (Flov control, suitability of Installed equipment, etc.):
APPENDIX B (Cont.)
III. DESIGN INFORMATION (Cent.)
B. UNIT PROCESSES (Cont.)
FLOW MEASUREMENT
FLOW STREAM MEASURED _
CONTROL SECTION:
TYPE AND SIZE
COMMENTS: (Operational problems, maintenance problems, unique features,
preventive maintenance procedures, etc.)
RECORDER:
'NAME
CALIBRATION FREQUENCY
DATE OF LAST CALIBRATION _
LOCATION
TOTALIZER
COMMENTS: (Operation and design problems, unique features, etc.)
III. DESIGN INFORMATION (Cont.)
III. DESIGN INFORMATION (Cont.)
I. UNIT ntncZSSES (Cont.)
B. "NTT rnOCKSSBS (Con5.)
PRELIMINARY TREATMENT
PRELIMINARY TREATMENT
HZCKA.1ICAL SAX SCREEN:
NAME.
WITHIH BUILDING:
DtscximQN or OPERATION:
_ HtiRSEPOWER __
HEATED?
COHMINIITOR:
NAME
STAKE rAXTS IKVBITORY:
HMO CU1WD) UK SCREE!!:
WIBTH
BAH CTAC1HC
CtEANIHC
UITHI.1 BUILDIKC?
WITHIN BUILDING?
MAINTENANCE:
SPARE PARTS INVENTORY:
COMMENTS:
PRIT B1WOVAI.:
DTSPOSAI. OF r,RIT:
DESCRIPTION OF UNIT:
PARTS INVENTORY:
. HORSEPOWER
HEATED?
SCttdlNCS DISPOSAL:
98
-------
III. DESIGN INFORMATION (Cont.)
B. UNIT PROCESSES (Cont.)
PRIMARY TREATMENT
PRIMARY CLARIFIER:
NUMBER SURFACE DIMENSIONS
WATER DEPTH (SHALLOWEST) ft X 0
HATER DEPTH (DEEPEST) f t x 0
305 = m
305 - m
HEIR LOCATION
HEIR LENGTH , ft r.-O
305 - a
TOTAL SURFACE AREA ft2 x 0.0929 - . ra^
TOTAL VOLUME gal x 0.003785 = cu m
FLOW (DESIGN) mftd x 3785
(OPERATING). ngd X 3785
HEIR OVERFLOW RATE
(DESIGN) gal/day/ft x 0.0124
(OPERATING) gal/day/ft x 0.0124
SURFACE SETTLING RATE .
(DESIGN) gal/day/aq ft x 0.0408
(OPERATING) sal/day/sq ft X 0.0408
HYDRAULIC DETENTION TIME (DESIGN)
= cu ra/day/sq m
= cu raA'ay/sq m
(OPERATING)
COLLECTOR MECHANISM NAME
MODEL HORSEPOWER
SCUM COLLECTION AND TREATMENT:
MAINTENANCE:
SPARE PARTS INVENTORY: *
III. DESIGN INFORMATION (Cont.)
B. UNIT PROCESSES (nonft.)
SECONDARY TREATMENT
AFB (Activated Bio Filter)
NAME NO. CELLS
MODEL FREEBOARD
MEDIA DEPTH ft X 0.305 °=
TOTAL MEDAI VOLUME ft3 X 0.028 =
2
I»3
RECIRCULATION TANK: DIMENSIONS
VOLUME gal X
RECIRCULATIOH:
MAINTENANCE:
COMMENTS:
0.003785 - cu m
III
n. UNIT pRnrr.r.rrs (f>nf.
AERATION BASIN:
KO. BASINS
APPENDIX B (Cont
. DESIGN INFORMATION (Cont.)
' SEPTODART 7REArM".ST
SURFACE DIMENSIONS
.)
WATER DEPTH
FLOW (DESIGNS
(OPERATING)
SEWAGE DETECTION T»
BODj LOADING
(OirniTTlSnV
mvRPFnt
TOTAT, VOI.1-WE
TYPE or AKPATT.1K
NS.ME
MODE OF OPERATION:
TYPE OF DIFFUSERS:.
NUMBER COMPRESSORS
MODEL
AIR CAPACITY (cfra)
me.d x 3785 - c
lb/1000 cu £t/day x 16.0 = cra/c
lb/1000 cu ft/day x 16.0 - p«/c
pnl x 0.003785 -
NO. AERATORS
MODEL HORGEPOHER
NAME
HORSEPOWER
LICATIOS
i.' IP /day
i m/dav
i m/dav
CU IP
MAINTENANCE:
SPARH' PARTS INVENTORY:
COMMENTS: -
III.
B. UNIT PROCESSES (Cnm . 1
DESIGN INFORMATION (Cont.)
SECONDARY TREATMENT
ROTATING BTOLOCICAL CONTACTOR (RBC) :
NO. SHAFTS LENGTH OF SHAFTS -f.r. x O..W4S -
HO. CELLS CELL
NAME
DISC DJJUffiTER
VOLUME 8,01 x 0. 003785 =
ft x 0.30I1S -
1-..JH
.«*_ n>
n
RPM
PERIPHERAL VELOCITY
TOTAL SURFACE AREA
PERCENT SUBHERGENCF,
FIflW (DESIHN1
(n»FRATTW,)
' HYPRAULIC IX)ADTKO:
(DESIGN)
(OPERATIC)
TEMPERATURE (DESIGN)
ORGANIC LOADING
(DESIGN)
(OPERATING)
TOTAL DETENTION TIMF.
COVERED?
ft/sec X 0.2048 =
sq ft x 0.0929 -
.mgd x 3785 =
Ib BOD/day/1000 sq f t x 4.885
kf, BOn/tiay/iOOO sq, m
(DFSIGN) hr (OPERATOIC) hr
HEATBi?
MAINTENANCE:
SPARE PARTS INVENTORY:
COMMENTS:
99
-------
III. DESIGN INFORMATION (Cont.)
a. UMII pnorjxsrs
-------
III. DESIGN INFORMATION (Cont.)
B. UNIT PROCESSES (Cont.)
CONTACT BASIN:
SURFACE DIMENSIONS _
WATER DEPTH
VOLUME
DISINFECTION
_ft X 0.3048 •
_gal x 0.003785 -
DETENTION TIME (DESIGN)
COMMENTS:
CHLORINATOR:
NAME
mln (OPERATING)
__cu m
min
CAPACITY
TYPE INJECTION
FEED RATE (OPERATING)
DOSAGE (OPERATING)
DIFFUSERS ',
_lb/day x 0.454 >
_kE/day
_lb/day x 0.454 '
_kg/day
SPARE PARTS INVENTORY:
MAINTENANCE:
COMMENTS:
APPENDIX B (Cont.)
III. DESIGN INFORMATION (Cont.)
B. UNIT PROCESSES (Conn.)
AEROBIC DIGESTION:
NO. BASINS
SLUDGE HANDLING
WATER DEPTH
VOLUME
COVERED?
TYPE OF AERATION
NO. AERATORS __.
MODEL
. SURFACE DIMENSION(S)
ft x 0.3048 = _
gal x 0.003785 '
TYPE OF DIFFUSERS:
NO. COMPRESSORS
MODEL
• AIR CAPACITY
LOCATION:
eta x 0.028 •
cu m/min
SPARE PARTS INVENTORY:
MAINTENANCE:
MODE OF OPERATION:
COMMENTS:
III. DESIGN INFORMATION (Cont.)
B. UNIT PROCESSES (Cont.)
SLUDGE HANDLING
ANAEROBIC DIGESTION:
SO. DIGESTERS DIAMETER
ft X 0.3048 >
SIDEWALL DEPTH
CENTER DEPTH
TOTAL VOLUME
FLOATING COVER? _
FLOW (DESIGN) __
(OPERATING)
III. DESIGN INFORMATION (Cont.)
B. IINXT PROCESSES (Cnnt-.)
SLUDGE HANDLING
SLUDGE DRYING BEDS:
NO. SIZE
COVERED? SBBNATANT DRAIN TO
ft x 0.3048. " .
_gal x 0.003785 »
_mgd x 3785 "
_mgd x 3785 -
DETENTION TIKE (DESIGN)
'HEATING:
MIXING:
SUPERNATING CAPABILITY:
SPARE PARTS INVENTORY:
MAINTENANCE:
MODE OF OPERATION:
COMMENTS:
days (OPERATING)
_EU in/day
_cu n>/day
days
DEWATERED SLUDGE REMOVAL:
MODE OF OPERATION:
OTHER DEWATERING UNIT(S):
101
-------
III. DESIGN INFORMATION (Cent.)
C. OIHH DESIGN IKTOBHATIOll
STAXD-IT POWER!
OMit STSTDS!
rasciuAmoust
APPENDIX B (Cont.)
III. DESIGN INFORMATION (Cont.)
D. PLANT AUTOMATIC!
E. LABORATORY CAPABILITY:
LOCATION
FLOOR DIMENSIONS
COUNTER SPACE
FILE CABINET?
TESTS PERFORMED BY WHOM
OPERATIONAL TESTS CONDUCTED (TSS, D.O., S.V.I., BOD, pH, & OTHERS) AND
FREQUENCY:
MONITORING TESTS CONDUCTED (TSS, BOD, pH, FECAL COLIFORM, OTHERS) AMD
FREQUENCY:
QUALITY CONTROL:
IV. : PLANT PERFORMANCE
A. SOCBCtS OF tUOtt PEXFOKMANCE DATA:
S. DATA AID DISCUSSIONS:
V. OPERATION AND MAINTENANCE PROCEDURES
A. OPERATION,rnwrflftj. pRnr.Rn!m.F.:
MAINTENANCE:
SCHEDULING PROCEDURE FOR PREVENTIVE MAINTENANCE:
EMERGENCY MAINTENANCE:
C. 0 S M MANUAL, SHOP DRAWINGS, EQUIPMENT MANUALS, AS-BUILT PLANS, ETC.:
D. TECHNICAL GUIDANCE:
102
-------
VI. ADMINISTRATION
A. ORCAHTZATXON:
GOVERNING JV>D¥
NO. MEMBERS
, TERMS OF .ELECTION
SCHEDULED MEETINGS
AUTHORITY AND RES?ONSIBILITlt:
CHAIN OF RF,SPr>NSIBIT,m.K;:
APPENDIX B (Cont.)
VI. ADMINISTRATION (Cont.)
B. PTANT PERSONNEL:
PERSONNEL CLASSIFI/WCION (TITLF., NUMBER, PAT SCALE, HSACTION OF TIME
SPENT AT SEWWE TREATMENT, CERTIFICATION GRADE):
C. PLANT COVERAGE:
WEEKDAYS
WEEKENDS S HOLIDAYS
VI. ADMINISTRATION (Cont.)
VI. ADMINISTRATION (Cont.)
D. PIANT JJimriET:
REVENUE:
TYPE OF TAP
D. PLANT BUDGET
-------
VI. ADMINISTRATION (Cone.)
D. tuuT KIWCT (Cone.)
(none.)
tana Tits
INTEREST |
DURATION BATE PROJECT FINANCED
• i • ....!-..-jf> ;
'. : H' a rj'.. J,: 'il
. ;n ! ). :>s:' ! ;. r •' >'. •• -\ :;:
' c'ii M. U'-ii.;
APPENDIX B (Cont.)
VI. ADMINISTRATION (Cont.)
DOLLAR AMOUNT PERCENT OF TOTAL
D. PLANT BnnCET (Cont.)
DISCUSSION OF EXPENDITURES:
BUDGET FOR:
SALARIES (INCL. FRINGES)
( ;• : :,.UTILITIES
SUPPLIES
CHEMICALS
TRANSPORTATION
' ,. , jTRApING & .EDUCATION
' '.'. ', • .-' ., .MISCELLANEOUS.^ ° - ~ ,'.-.... 1. „ ...
OPERATIONS SUBTOTAL
CAPITAL OUTLAY
(Incl. Bond Debt Retirement)
•;. . «;..;;, i;.. • .•;:„,».. la,' t :(>; jr..; ••/;.: '»•
, OPERATIONAL COST PER MILLION GALLONS (OPERATIONS^SOBTOTAL r^YEARLY FLOW)
' | i !»t ' •:(':.) % If- T-' 'Si''me." t 10 « '' - ? c/l'OOb'cal X 0.264 . ='
,.- . t . . , j -.,,,, , . . , . .„..,;. > * f i i * : ; a C/r.u m^'
: • , ' ,' ' £ * i ,' " t ? .; i i • . J i I T • 1 c •v [ ^
' " APPROXIMATE ANNUAL COST PER TAP (TOTAL t NO'. "TA>S) ' '' ' "
• i ,-f i . ''• r V. "T! + ^ V [taps »' S r. ' '' : /' -'' /tab'
DISCUSSION: , . , .
; I • • • ?.. i;;'5!»i.'.- :...; r'j ii :',-i-:• t"':n.' us
, :, •':> . '.'I'.,'' • 'Jh
VI. ADMINISTRATION (Cont.)
». rum Mimrr
Dayi in
Billing
Year F«r!nJ KWH
Coat c/Kwh Floy
KUH/DAT __
nni/iooo ga
i p/day
c/1000 r,nl .
C/cu ra
COST S1TMHARY
Electrical
Salaries
Toeal Cp«raeiona
Toeal Coac
104
-------
APPENDIX C
PLANT EVALUATION SUMMARY FORMS
Plant Evaluation Summary forms were developed for the project to deter-
mine and rank the factors limiting performance at wastewater treatment facili-
ties. Part 2 of the Summary (the weighing table) was used to note the causes
of less than optimum performance in the areas of administration, maintenance,
design and operation. , A point system was used, to express the severity of
problems noted. Part 1 of the Summary (the ranking table) was used to rank
the performance-limiting factors noted as severe according to their magnitude
of importance. Definitions of the terms used in the Plant Evaluation Summary
are included.
105
-------
RAKCINC TABLE
ACTUAL FlOV:
tIAXCTMOST HKZKr OTGRADE!
run rarcKuscr SCKUKYI
RAHC1KC IA1LE (PART 1)
APPENDIX C (Cont.)
Plant Number
Design. Flow
Actual Flow
Year Plant Built
Year of Most
Recent Upgrade
Plant Performance
Ranking Table
Ranking
Table Reference
Cause
Point
RAKKIHG TABLE DEFINITION OF TERMS .
This in an in-house identification and reference number
assigned to plant by H & I, Inc. A numbering system is
used rather than a specific plant name.
Specific description of type of plant (e.g. 2 stage
trickling filter with anaerobic digestor or extended
aeration activated sludge with polishing pond and with-
out sludge digestion).
Plant design flow rate as of most recent upgrade.
Sewage flow rate for current operating condition (e.g.
for past 1 to 2 months). Also significant seasonal
variation in flows will be noted.
Year initial units were put into operation that.are still
functioning.
Year last additional major units were put into operation
(e.g. digester, chlorine contact chamber, etc.)
Brief description of plant performance as related to
present and anticipated treatment requirements.
List in descending order the major causes that were
detrimental to plant performance and reliability.
Begin with the most critical cause of decreased plant
performance and reliability.
Letter and number of causes as shotm in the Weighting
Table (Pages 2-7).
Name of cause as shown in the Weighting Table.
Points given each cause as shown in the Weighting Table.
WEIGHTING TABLE (PART 2)
WEIGHTING TABLE (PART 2)
PTS
COMMENTS
A. AJHlHtSTRATIMt
b. References Available
1. Mane Adainifitrators
c. Spare Parts Inventory
a. Polieics
3. Emergency
b. FaaUiarUy vlth Plant Needs
a. Staff Expertise
flant Staff
b. Critical Parts Proi
Hanpouer
Technical Guidance
1. Huaber
2. Plant Coverage
1. Plant Loading
3. Plant Kanageaant
b. Morale
b. Hydraulic
t. Motivation
2. Pay
3. Supervision
Seasonal Variation
4. Plant Esthetics
f. Infiltration/Inflow
5. Safe Working Conditions
c. Productivity
2. Unit Design Adequacy
Personnel Turnover
a. Preliminary
3. Financial
b. Primary
a. Insufficient Funding
c. Secondary
b. Unnecessary Expenditures
1. Process Flexibility
c« Band Indebtedness
2. Process Controllability
KAINTtXXV'CE
3. Aerator
i. General
4. Clarlfier
d. Advance Waste Treatment
a. Housekeeping
b. Equipaant Ago
c. Scheduling & Recording
d. Manpower
2. Preventive
a. Laefc of Program
106
-------
WEIGHTING TABLE (PART 2} ,
CATEGORY
e . Disinfection
f . Sludge Wasting Capability
g. Sludge Treatment
h. Ultimate Sludge Disposal
3 . Miscellaneous
a. Plant Location
b. Unit Process Layout
c. Lack of Unit Bypass
d. Hydraulic Profile
1 . Flow Backup
2. Submerged Weirs
3. Flow Proportioning to
Units
e. Alarm Systems
f . Alternate Power Source
g. Process Automation
1. Monitoring
2. Control
h. Lack of Stand-by Units for
Key Equipment
i. Laboratory Space & Equipment
j. Process Accessibility
for Sampling
k. Equipment Accessibility
for Maintenance
1. Plant Inoperability Due
to Weather
m* Quality of Equipment
n.
PTS
COMMENTS
APPENDIX C (Cont.)
WEIGHTING TABLE (PART 2)
" CATEGORY
D, OPERATION
1. Staff Qualifications
a. Ability
1 . Aptitude
2. Level of Education
. , b. .Certification
_1. *Level of Certification
- - • 2. Training • < - - *
• • c. Sewage Treatment Under-
standing
d. Insufficient time on the
Job (Green Crew)
2. Testina
a. Performance iflnn
-------
3< Plane Kanageatnt
b. Koralo
1. Motivation
2. Fay
3* Supervisor
4. Plant Esthetics
5. Safe Working
Conditions
e. Productivity
d. Personnel Turnover
3. financial
a. Insufficient Funding
provided because the operators "get ilnto
each others way?" ' E
[
Do formal personnel development programs
exist? Are formal "Annual Reports"'is-
sued? Is there written evidence of ,
Planning, Organizing, Staffing, Delega-
tion and Controls?
Is the plant staff motivated to do a
'good job by self satisfaction? I
Docs a low pay scale discourage more
highly qualified persons from applying
for operator positions or cause operator!
to leave after they are trained?
Docs-the plant superintendent and opera-
tor or supervisor and operator working
relationship cause adverse operator lin-
centive?
Does a poor working environment create a
condition for more "sloppy work habits"
and lower operator morale?
Are safety statistics kept and reported?
Are there regular safety meetings or
posted safety guides? Do unsafe working
conditions cause operators to avoid [
taking aeasures to control the plant?
Docs the plant staff conduct the daily
operation and maintenance tasks in an
efficient manner? Is time used effic-
iently? _ ' I
Docs a high personnel turnover rate !
cause operation and/or maintenance pro-
blems which affect process performance
or reliability? I
Does the lack of available funds cause
poor salary schedules, insufficient 'spare
parts and equipment repair, insufficient
b. Unnecessary.
Expenditures
c.' Bond Indebtedness
MAINTENANCE
1. General
a. Housekeeping
b. Equipment Age ,
c. Scheduling and
Recording
d. Manpower
2. Preventive ," ,
a. Lack of Program
APPENDIX C (Cont.)
capital outlay for improvements, etc?
Does the manner in which available funds
ar;e dispersed cause problems in ob-
taining needed equipment, staff, etc?
Is the money spent wisely?
Does the annual bond debt payment limit
the amount of funds available for other
. needed Items like equipment, staff,
etc.? Does a disproportionate amount
of the total budget go for bond debt
.retirement? - . . ' ,i>
Has a lack of good housekeeping proce-
dures (e.g., grit channel cleaning, bar
screen cleaning, unkept, untidy, or
cluttered working environment) caused
an excessive equipment failure rate?
Has the age or outdatedness of critical
pieces of equipment caused excessive
equipment down time and/or inefficient
process performance and reliability
(due to unavailability of replacement
parts?) ;i
Has the absence or lack of an effective
maintenance scheduling and recording
procedure created a condition for an
erratic preventive jnaintenance program
that has caused unnecessary equipment
failure?
Has .the lack of adequate maintenance
manpower caused prevented maintenance
functions to not be completed to pre-
vent equipment breakdown or emergency
equipment repair .to be delayed? ,L!
- Has the absence or extreme lack of an
effective maintenance program caused
unnecessary equipment failures or ex-
fa* Reference Available
c. Spare Parti Inventory
3.
a. Staff Expertise
b. Critical farta
Procurement
e. Technical Guidance
C. BESICH
S. Plant loading
ccssive down time that has degraded.
plant performance or reliability?
Has the absence or lack of good equip-
acnt reference caused unnecessary equip-
ment failure and/or down time for repair
(includes maintenance portion of 0 '& M
Banual)? I
\
Has a critically low or non-existent
spare parts inventory caused unnecessary
long delays in equipment repair which
has caused degraded process performance?
Does the plant staff have the necessary
expertise to keep the equipment operat-
ing and to make smaller equipment re-
pairs when necessary? '
I
Have delays in getting replacement parts
caused extended periods of equipment
down time?
If technical guidance for repairing1 or
installing equipment is necessary tb
decrease equipment down time, is itf
retained?
Has the presence of "shock" loading
characteristics over and above what1 the
plant was designed for or over and above
what is thought to be tolerable caused
degraded process performance by one or
aore of the listed loadings (a-e)? |
f. Infiltration/Inflow
g. Return Process Stream
Unit Design Adequacy
a: Preliminary Treatment
b. Primary Treatment
c. Secondary Treatment
1. Process Flexibility
a. Organic
b. Hydraulic
c. Industrial
d. Toxic
o* Seasonal Variation
2. Process
Controllability
Does excessive infiltration or inflow
cause degraded process performance be-
cause the plant cannot handle the extra
flow?
Does an excessive volume and/or a high-
ly organic or toxic return process, flow
stream cause adverse affects on process
performance, equipment problems, etc.?
Do the design features of any prelimi-
nary treatment unit cause upsets in
downstream processes or excessive down-
stream equipment wear and tear that has
led to degraded plant performance?
Does the shape of the unit, or location
of the unit lend to its accomplishing
the task of primary treatment? Does
the unit have any design problem area
within it that has caused it to perform
poorly?
Does the non-availability of adequate
valves, piping, etc. limit plant per-
formance and reliability when other
modes of operations of the existing
plant could be utilized to improve
performance (e.g. operate activated
sludge'plant in plug, step, or contact
stabilization mode; operate trickling
filter with constant hydraulic loading
or recirculation ratio; discharge good
secondary treatment effluent as opposed
to a degraded "polishing pond" effluent;
etc.)?
Do the existing process control features
provide, adequate adjustment and
measurement over the appropriate flows
(e.g. return sludge) in the range
necessary to optimize process perfor-
mance, or, is the flow difficult to
adjust, variable once adjusted, not
measured and recorded, not easily
108
-------
4. Clarifier
d. Advanced Waste
Treatment
e. Disinfection
f. Sludge Wasting
Capability
. .g. Sludge .Treatment
h. Ultimate Sludge
Disposal
measurable, etc.?
Does the type, size, shape, or location
of the aerator hinder itsf ability fcb_
adequately treat the sewage and provide
for stable operation?
Does a deficient design cause poor sedi-
mentation due to the size of the clari- •
fier, placement of the weir, length of
weir, type of clarifier, or other mis-
cellaneous problems?
'Any process of wastewater treatment
which upgrades water quality to meet;
specific effluent limits which cannot
be met by conventional primary and
secondary treatment process (i.e'.J' ''
nitrification towers, chemical treat-
ment, multi-media filters)'. '"'* (Space has
been allowed for in the table to
'accommodate all advanced processes en-
countered during the research project.)
Does the shape or location of the unit
lend to its accomplishing disinfection
of the wastewater? (i.e., Proper
mixing, detention time, feeding rates
- proportional to flow, etc.)?
Does the plant have sludge wasting facil-
ities? If so can a known volume of
sludge be wasted? Can sludge wasting be
adequately controlled?
'Does the type or size of sludge treat-
ment processes hinder sludge stabili-
1zation (once sludge has been removed
from the wastewater treatment system)
which in turn effects process operation
(e.g., causes odor problems, causes
• limited sludge wasting, etc.)?
Are the ultimate sludge disposal facili-
ties of sufficient size and" type to ade-
quately handle the sludge? Are there
any specific areas' "ttiat limit ultimate
sludge disposal such as seasonal weather
variations, crop harvesting, etc.?
3. Miscellaneous
a. Plant Location
b. Unit Process Layout
_ c*- Lack;pf Unit Bypass -
d. Hydraulic.Profile
r 1., Flov Backup t i
2. Submerged Weirs
3.. .Flow.Proportioning
to Units
, e. - Alarm System,
APPENDIX C (Gont.)
The design miscellaneous section covers
areas of design inadequacy not speci-
fied in the previous design categories.
t . (Space has been allowed to ±accommodate
.additional items not"listed) .
,. Does, a poor plant location or poor roads
• leading into the plant cause*"it to be
inaccessible during certain periods of
the year (e.g. winter) for chemical or
equipment delivery or for routine opera-
i tion? :; L- •
Does the arrangement of the unit pro-
, cess,es cause inefficient utilization of
•t operator's time for checking various
•processes, collecting samples, making
adjustments, etc.?
Does the lack of unit bypass cause plant
• upset and long term poor treatment when
a:short term bypass could have mini-
mized, pollutional load to the receiving
waters; caused necessary preventive
;: maintenance items ^ to'be cancelled or
.delayed; caused more than one unit to
,- .be out of service when maintaining only
one unit?
Does an insufficient hydraulic profile
cause ground flooding or flooding of
upstream units except clarifiers? Does
periodic release of, backed up flow cause
hydraulic surge?
Does an insufficient hydraulic profile
cause flooding of clarifiers and sub-
merged clarifier weirs? , , •
Has. inadequate flow proportion or flow
splitting to duplicate units caused pro-
blems in partial unit overload which
degraded effluent quality or hindered <
achieving optimum process performance?
Has the absence or inadequacy of a good
alarm>system for critical pieces of
equipment caused unnecessary equipment
f. Alternate Power Source
g; Process Automation
I. Monitoring
h. Lack of Stand-by.Units
for Key Equipment
i. Laboratory Space and
Equipment
j. Process Accessibility
for Sampling
k. Equipment Accessibility
for Maintenance 1 -
failure or in'any way .caused degraded
process performance?
Does, the' absence of an alternate power
source cause problems in plant opera-
. tj,on and/or plant performance?. ..,
Has the lack of needed automatic moni-
toring devices (D.O. meter, p!i .meter, - •
etc.) caused excessive operator time to
water, for slug loads or process upset
to occur because of slug loads? Has a
breakdown or the improper workings of
automated process monitoring features
(caused disruption of automated control
features and subsequent degradation of
process performance?, ;r ......
Has the. lack of a needed automatic con-
trol device (time clock) caused exces-
sive operator time to make process con-
trol changes or necessary changes to be
cancelled or delayed? Has the break-
down or the improper workings of auto-
matic control features caused degrada-
tion of .process performance?
Has; the lack of stand-by units for key
equipment caused degraded process per-
formance during breakdown or necessary
preventive maintenance items to be
cancelled or delayed?
Does the absence of an adequately
equipped laboratory indirectly limit
plant performance by the lack of opera-
tional testing and performance moni-
toring?
Has the inaccessibility of various pro-
* cess flow streams (e.g.,: recycle
streams) for sampling caused, needed in-
formation to not be obtained?
'Has the inaccessibility of various
pieces of equipment caused extensive
down time or difficulty in making needed
1. Plant Inoperabllity
DUG co Wiiather
m. Quality of Equipment
OPERATION
1. Staff Qualifications
a. Ability
1. AptltucJe
2. Level of Education
. b.-.. Certification
1. Level of
. Certification
2. Training
c. Sewage Treatment
Understanding
repairs or adjustments.
Are certain units in the plant extreme-
ly vulnerable ttTweather changes (e.g.,
cold temperature) and as such do not
operate at all, or do not operate as
efficiently as necessary to achieve the
required performance?
Has the poor quality of plant equipment
resulted in excessive repairs and main-
tenance?
Has the lack of the capacity for learn-
ing or undertaking new ideas by staff
• members or critical staff members
caused poor 0 & H decisions to be made
which has caused poor plant performance
or reliability?
: Does a low level of education cause
poor 0 & M decisions to be made? Does
a high level of education but a lack of
process understanding cause needed
training to be overlooked?
Does the lack of adequately certified
operators cause poor process control
•decisions?
Does the operators non-attendance of
available training programs cause poor
process control decisions?
Has the opertors* lack of understanding
of sewage treatment in general been a
factor in poor operational decisions
and poor plant performance and reliabil-
ity?.
109
-------
d. Insufficient Tina on
Job (Green Grew)
2. Testing
a. Ferforunze
Monitoring
b. Process Control
TCItins
3. Process Control Adjustacnts
a. Operator Application of
Concepts and Testing
to Procest Control
b* Technical Guidance
4. 0 t M Manual
a. Adequacy
b. Use by the Operator
5. Miscellaneous
Has a short time on the job caused im-
proper process control adjustments to be
made because of opening or closing a
wrong valve, turning on or off a wrong
puap, etc.? 1
Are the required monitoring tests [being
completed in compliance with the dis-
charge peraitj [
Has the absence or wrong type of pro- '
cess control testing caused improper
operational control decisions to be
eadc?
Has the operator been deficient in' the
application of his knowledge of sewage
treatment and the interpretation of his
process .control testing, to process'con-
trol adjustments? I
Has false operational information re-
ceived from an equipment supplier,'or
frora B paid technical consultant,
caused Improper operation decisions
to be continued? Has a technical per-
son (design engineer, state engineer,
etc.) failed to address obvious opera-
tional deficiencies while being in a
position to correct the problem? ;
Has a poor 0 & M Manual resulted in the
operator caking poor or improper opera-
tional decisions?
Has a good 0 & H Manual not used by the
operator caused poor process control and
poor treatment that could have been
avoided.
The operations miscellaneous category
deals with any pertinent operational
Information not covered in the previous
a. Equipment Malfunction
b. Shift Staffing
Adequacy (Operations)
APPENDIX C (Cont.)
operational sections. (Space has been
allowed to accommodate additional items
not listed.)
Does malfunctioning equipment cause
deteriorated process performance?
Has the improper distribution of ade-
quate manpower caused process controls
to not be made, or be made at inap-
propriate times which In turn has
caused poor plant performance?
110
-------
APPENDIX D
PLANT EVALUATION SUMMARY
FOR
SITE VISIT FACILITIES (PHASE II)
Plant Evaluation Summarizes for plants where site visits were conducted
differ from the comprehensive evaluation results because only a one-half day
evaluation was made, whereas a one-week evaluation was made at comprehensively
evaluated facilities. Therefore, only the more obvious factors limiting
performance were determined during site visits. The Plant Evaluation Summary
results for the Phase I site visits have been previously reported (5).
Ill
-------
mutr HO. BM :
OESICX 710U: 39.740 eu B/dsv flO.5 n«dl
ACrBAL FUN: 1SHO cu B/day (4 Hid)
TCAX mar HJILTI 1917 ;
TCJUl Or HOST UCEXt UPGRADE: 1974
njurr rarosxASCE SUHXAST: i
Stan&re' saconcary treacaent required. Effluent BOD reported as 15 ng/1.
So solid! loss problcas reported.
RANKING TABLE (PART 1)
RAXxno
i
3
1
4
5
«
7
a
•
10
TAJIK KraEKCE
C.2.f .
C.2.C.3.
C.2.C.I.
C.Z.h.
CAUSE
Sludge Treatment
Aerators
Process Flexibility
Ultlaate Sludge Disposal
MISTS
2
2
2
2
1
APPENDIX D (Cont.)
PLANT NO. 067
PUNT TYPE: Trickling Filter/Aetlmitpd Slnito« .....'
DESIGN FLOW: 24,600 cu »/day (6.5 ngd) _• ' • ' '
ACTUAL FLOW: 16,275 cu a/day (4.3 mgd) ' ' ' '
YEAR PLANT _BUILT: 1962 .
YEAR OF MOST RECENT UPGRADE: 1975 ; ••••••-',
PLANT PERFORMAMCE SUMMARY : . • :- 1
Plant records of operation indicate very good performance with BOD. and
TSS values generally less than 5 ng/1 and ammonia less than 1 rag/1.
RANKING TABLE (PART 1) -
RANKING
I
2
3
4
5
6
7 :
8
9
10
TABLE REFERENCE
D.3.a.
CAUSE
Operator Application of Concepts and
POINTS
2
i
rUUTT SO. 071
IttXI mtt S!iwle-Scaso Trickllrai Filter v/Stornee Ijiaoon
DKId FLOW: 3715 cu a/day (1 Bud)
ACTCAL FLOW: 3785 cu a/day (1 aid)
TUX HAST KiUT: —
TUX Or HOST KCCEXt UPGRADE: 1973
FLAW mrOIHANCE SUKXARY:
Plane haa consistently aet secondary standards, but Is being replaced
Co Beat new Bore stringent standards. i
1
RANKING TABLE (PART 1) ;
XAXxruc
l
i
3
4
5
(
7
1
*
10
TABLE REFERENCE
C.2.C.3.
C.l.f.
CAUSE
Aerator
Infiltration/Inflow
FOUNTS
2
2
i
,
PLANT NO. 072
PLANT TYPE: . . Activated Sludge
DESIGN PLOW: . 3028 cu m/day (0.8 mgd) . . , "-. _- , ,'
ACTUAL FLOW: 3028 cu m/day (0.8 mgd) ,- , . . , ' ,
YEAR PLANT BUILT: 1973 . ._. .- ' -,-.,','
YEAR OF MOST RECENT UPGRADE: No Upgrade • -
PLANT PERFORMAMCE SUMMARY:
Appeared Co meet secondary standards.
RANKING TABLE (PART 1)
RANKING
1
2
3
4
5
6
7
8
9
10
TABLE REFERENCE
D.3.a.
C.2.C.3.
C.2.C.2.
CAUSE
uperacor Application of Concepts. and
Aerator =
Process Flexibility
POINTS
.,2 •
2 • -
• 2
.112
-------
-
PLANT TYPE: Activated Sludge
DESIGN FLOW: 4542 cu m/day <1.2 mgd)
ACTUAL FLOW: 5678 cu m/day (1.5 mgd) , , ,
YEAR PLAHI BUILT: 1975 . "
YEAR OF MOST RECENT UPGRADE: No Upgrades , : • ,- ; , . . ,-,..,- ^ L i
PLAHT PERFORMANCE SUMMARY:
(Plant has met secondary standards in recent months following a,
period of nbn-corapliance. . : . •
RANKING, TABLE (PART 1).,
RANKING
1
2
3
4
5
6
7
8
9
10
TABLE REFERENCE
, -. D,5.a.. .
C.2.C.3.
C.2.C.1
^ , CAUSE .•.:',
Equipment Malfunction
Aerator
Process Flexibility
"
'."SpiTO ""•
•--j---.-
,2
"•• 2 '
: ';
• ""
-• ,, - -,„-
PLANT TYPE: Contact Stabilization Activated .Sludge - ; •
' DESIGN PLOW: 6435 cu m/day (I.?' mgd) "-" .'.'"." '.""'," ''"• ..'•""..'••'
ACTUAL FLOW: 4920 cu m/day (1.3 mgd) 'up to 7l6 ,22Q r cu m/day (2. 7}" in 'wet weatl
YEAR PLANT BUILT: 1929 . . .;.,
YEAR OF MOST RECENT UPGRADE: 1951 ' ' " ".'.'-"'^ '~. " ;.~~'".~ ' ' ,"'-.
PLANT PERFORMANCE SUMMARY: •, : - _':,. , .. _
Plant records , indicate secondary treatment is..met Qr nearly met, but ,
the operator bypasses primary effluent up tofl mgd .'during rain, and reports
•solids loss for periods of an hour or so every 15 to 20 days.
RANKING .TABLE (PART, 1)
; RANKING
1
: 2
3
4
": 5
6
7
8
9
10
TABLE REFERENCE
C.l.f.
1 D.3.a.
C.2.C.4.
C.2.C.I.
1 C.2.C.2. '
D.2.b.
!•'• •' "" CAESEf"^ . ~~"~,' '."• "~
Infiltration/Inflow. \- -- ~ - * - - •
Testine to Prdcesd Control •
Clarifie? , ~ 7 ~. ", f V' -•'••--
Flexibility ' " • • r " ' • ' .'•;
Controllability
Process Control Testing " . - - .
* ' ' " ' ' ' J
' •• • • • -
.POINTS
. 3- --
3
," 3,' -
' f" " '
>"" -
"'2
APPENDIX D (Cont.)
. - . .• •>.-- -
PLANT TYPE: Imhoff Tank/Trickling Filter - . - i • ' • •. .
DESIGN FLOW: 300* cu m/day (6.08 mgd) . ....... :>•
A'CTUAL FLOW:. ISO cu m/day (0.05 Bgd) ' " ' '.;":".' "•
YEAR PLANT BUILT: 196*1 "' ~ ,,'.,'" " . ""..,;. ' ... . T,'"
YEAR OF MOST RECENT UPGRADE: None " "1 ' .,-';'•'••''
PLANT PERFORMANCE SUMMARY: . . . .
Does not meet secondary standards consistently. Bypasses during
high infiltration.
_. . . . . .
;, .-
RAXKim;
1
"" 2
3
•• • 4
,.-- 3
6
7
8
9
'" 10
TABLE REFERENCE
C.2.e.
D.'3.«. —
"• c:i.f.
C.2.C.3.
\NK1HG TABLE (PART 1) ~ •
CAUSE.
Sludge Treatment
resting to Prnff^ rnn^T•n^
Infiltrati'on/InfloV"
Serator
POINTS
3 '
. 2
2 ,
2
PLANT TYPE: Activated Sludge w/Polishing- Lagoon ,
DESIGN FLOW: 1890 cu m'/day (0.5 mgd) ;
ACTUAL FLOW: 1135 cu m/day (0.3 mgd) . .
YEAR PLANT BUILT: —
YEAR OF MOST RECEHT UPGRADE: 1969 . .• .
PLANT PERFORMANCE SUMMARY: , , • -
Violated standards frequently.
:•" ' . ' " ""• RANKING" TABLE (PARTI) , -•
RANKING
: 1
: 2
3
4
5
6
7
8
; 9
10
TABLE REFERENCE
C.2.f.
D.3.b.
D.l.c.
C.l.f.
C.2.C.4.
C.2.C.2. '
C.2.C.I.
'
CAUSE
Sludge Wasting Capability
Technical Guidance
Sewage Treatment Understanding
I/I
Clarifier
Process Controllability
Process Flexibility
POINTS
3
3
3
3
3
2
1 2
113
-------
rum imi TUO-SUEC Trickling Fllcer (
Dtsiotrtowi MM cu »/d«y (2.5 ««« ' "7
ACTUAL FLOW: 3010 cu o/diy (0.8 cgd) "
TUUt rLUII K1IIT1 1952 '[."""
van. or MOST MOW UKUDS-. 1977 ' , ' t ' .
rtAXt MWOIIMA3CE SWfiUK: f ' '
Kit Bflc •tankards consistently. , * '
• i
i
RANKING TABLE (PART 1) |
IUXXIK:
1
2
1
»
5
i
7
t
»
10
TAME KFEMSCE
C.2.C.3.
C.2.J.
CAUSE
Aerator
Sludge Treataent
PpINTS
'2 •
I2 -
1
1 ' '
1
' - -
!'
!".
I ,
APPENDIX D (Cont.)
DESIGN FLOW: 1890 cu m/day; 570 cu Wday (0.5 ngd/0.15 mgd)
ACTUAL FLOW: 1515 cu m/ddy; 300 cu m/day (0.4 mgd/0.08' »gd)
YEAR PLANT BUILT:
YEAR OF MOST RECENT UPGRADE: 1965 ' "
PLANT PE
Th<
meet stc
standarc
EFORMANCE SUMMARY: '
trickling filter performs quite well in summer, but does not
ndards In winter. The contact stabilization plant usually meets
RANKING TABLE (PART 1)
RANKING
1
2
3
4
5
6
7
8
9
10
TABLE REFERENCE
D.S.a.
D.3.b.
' c.2.g:
D.2.b.
CAUSE
Testing to Process Control
Technical Guidance
Sludge Treatment
Process Control Testing
POINTS
3
2
2
2
fLUtr nil: OxltUtlon Ditch :
BtSIQI TLOU: 3785 cu =/d.y (1 «gd) 1
ACTOU. FIDO: 1135 cu o/day (0.3 »gd) >
ItOL tlKII BUILT: 1935 1
TUX Ot HOST KICErt U7CXADE: 1977
PUOT nuonui-'CE SSHMAXY: , 1
FlflBt COMlltcatly aeeca effluent standards. 1
t
[
RANKING TABLE (PART 1) [
KJLtXISC
2
}
t
5
<
7
a
9
to
TAMJ: XEFOESCE
D.1.2.b.
CAUSE
Process Control Testing
PdlNTS
2
1
1
1
!
1
PLANT TYPE: Activated Sludge (Contact Stabilization)
DESIGN FLOW: Unknown
ACTUAL FLOW: Est. 300 cu m/day (80,000 cpd) . ' :
YEAR PLANT BUILT: 1966
YEAR OF-MOST RECENT UPGRADE: — . •
PLANT PERFORMANCE SUMMARY:
Reported problems with meeting permit standards. The City is
currently working with the State and the equipment manufacturer to
work out problems.
RANKING TABLE (PART 1)
RANKING
2
3
4
5
e
7
8
9
10
TABLE REFERENCE
CAUSE
POINTS
114
-------
PLANT NO
. 088
PLANT TYPE: Activated Sludge and Parallel Trickline Filter
DESIGN FLOW: 6813 cu .m/day (1.8 mgd) and 3785 cu m/dav (1.0 mad) " - '
ACTUAL FLOW: Dry Weather; 10600 cu m/day (2.8 mgd). Wet 17030- cu m/da'y (4.5 a
YEAR PLANT BUILT: IF - 1953 AS - 1973 ' - . : -
TEAR OF MOST RECEHT UPGRADE: 1973
PLANT PERFORMANCE SUMMARY:
Meets standards consistently according to plant records.
RANKING TABLE (PART 1)
RANKING
1 ,
2
3
4
5
6
7 ,
8
9
10
TABLE REFERENCE
C.l.f.
D.3.a.
: C.2.C.2.
C.l.d.
CAUSE - ,
Infiltration/Inflow1,
Testine to Process Control
Process Controllability
Toxics
POINTS
2-
2
, 2 , -
2 . . .
d)
APPENDIX D (Cont.)
..PLANT TYPE: Activated Sludge, (Contact, Stabilization)
DESIGN FLOW: 3860 cu m/day (1.0 mgd) , , '. ,,-.:, '
ACTUAL FLOW: 5680 cu m/day, (1.5 mgd) . .. .
YEAR PLANT. BUILT: 1965 ,.'.'...',
YEAR OF MOST RECENT UPGRADE: None
PLANT P£
PI
RFORMANCE SUMMARY:
RANKING TABLE (PART !)_.:: i
RANKING
. 1 ,
.2
3
4 .
., 5 ,
6
7
8
9
10
TABLE REFERENCE
, . ,A.2.b.l.
A.l.b. ,
, D.3.a.
. C.2,c.2. ,
CAUSE
Motivation = . . . ...
Familiarity w/plant needs
Operator Application of Concepts and
Process Controllability
POINTS
3
-2
2 ...
2 .
PLANT NO. 090
PLANT TYPE: Contact Stabilization w/Pollshing Lagoon
DESIGN FLOW: 1890 cu m/day (0.5 mgd)
ACTUAL FLOW:Dry 1890 cu. m/day (0.5 mgd); Wet as high as 17,000 cu ra/day-(4.5
YEAR PLANT BUILT: 1970
YEAR OF MOST RECENT UPGRADE: None
PLANT PERFORMANCE SUMMARY:
30/30 standards are exceeded the majority of the time. Clarifier
effluent is generally better than pond effluent except when solids are
lost due to I/I.
RANKING TABLE (PART 1)
RANKING
1
2
3
4
5
6
7
8
9
10
TABLE REFERENCE
C.l.f.
C.2.C.I.
D.3.a.
D.2,b.
C.2.C.2.
C.2.f.
CAUSE
I/I
Process Flexibility
TooM"rf*Ppi^"=°?-°^-?°<:ePt3 M<1
Process Control Testing
Process Controllability
Sludge Wasting Capability
POINTS
3
3
2
2
2
2
mgd)
PLANT NO. 091 ' . '
PLANT TYPE: Contact Stabilization
DESIGN FLOW: 2840 cu m/day (0.75 mgd)
'ACTUAL FLOW: Est. 1700 cu ra/day (Est. 0.45 mgd)
YEAR PLANT BUILT: 1976
YEAR OF MOST RECENT UPGRADE: None
PLANT PERFORMANCE SUMMARY:
Reportedly good, but lack of appreciation for process control and
especially sludge handling indicate periodic solids loss. Performance
poor during survey due to Clarifier scraper failure and lack of control.
RANKING TABLE (PART 1)
RANKING
1
2
3
4
5
6
7
8
9
10
TABLE REFERENCE
A.l.b.
D.S.a.
C.2.C.2.
C.3.-i.
D.5,a.
B.3.a.
C.2.h.
A.2.b.5.
CAUSE
Familiarity w/Plant Needs
Process Controllability
Lab Space and Equipment
Equipment Malfunction
Emergency Mtc. Staff Expertise
Ultimate Sludge Disposal
Unsafe Working Conditions
POINTS
3
3
3
2
2
2
• 2
2
115
-------
" 1
RJUrr TTTCl Conventional Activated Sludge 1
DtSICS rtOWl 7570 cu «/day (2.0 agd) i
ACTCAL ROW: 60(0 cu B/day (1.6 ogd) , :. . ,.
TCAX rLAHI KJILTl 1911 1' ' "
TEA* Of HOST MOST UPGRADE: Ho major upgrades '
TtAXT FEUOKXAilCE SUMXAB.T:
Plane appeared1 to be
report* Ittm the operators
Mlgi tlovt are bypassed to
standard*.
BODij fluctuated froa abou t , 5 to #30» mg
another plant dotmstreas which tloe? not
., i LI.,; • ; -r: i...
ani
tU-;:
ilM'f.
[
"•• •-•' • • WkNc'TABLE-CPARri)' ••'•-•"' 5 f'fi -r
'H.NXISC
I
2
3
>
5
6
7
a
»
to
TAItC X£ta t M
"PoUotcs * • L 7 •». • r ! :i '
-Process Controllability ' . t
Process Flexibility " * ' " ' '
upetatoc-,. Application o£ *Concopca;and;
T»«r>fWff rn Prnf'i.-i« rnnrynt-'^- ' '
Sludge Hasting Capability
: POINTS !i
:tt- •
.[2
-^ -•
-2> I :
|2
1
I
f
1
,.!
!
DESIGN FLOW: 6330 cu m/day (1.7 mgd)
, ACTUAL FLOW: 5680 cu m/day (1.5 ragd)
' YEAR^ PLANT BUILT: 1977
YEAR OF MOST RECENT UPGRADE: None
PLANT PERFORMANCE SUMMARY:
Meets standards during normal operation according to plant records,-
[ but^e'ports'tog "solids washout" indicate standards are violated periodically
: »•..»'•;•.••'•.; •. : ::?••;.!.-. ~ <<<<••. {D:<
' t i : . , '. Jf.i'. '.i: nju&iso TABLE "(^AKI •!*) ••''•''Hi 5 : i
• SAHiCniG
.,;•' 1
2
" 3' '
ft'*l!
5
6
7
6
9
10
TABLE1 REFERENCE
• r ; D.3.aj ' t
C.2.£. ',
C.S.c.4.'1-
: : : i ?•
. «: . -if . I" CAUSE - '•' • ••"•' •
Sludge Wasting Capability ...
Clarified -,.,.,•,»
.(:•:' "'(. . -TO ?..'(-• ••>'."
'• POINTS "
* 2 * •--
2
- 2 '
APPENDIX D (Cont.)
FIAXT »0. 098
FUST ITFEl Three-cell Aerated lasoon 1
OESICH FtOU: 7570 ou ./day (2 =gd) !
ACTUAL FLOVl Uriknoun. est. approxiraately 3785 cu a/day (1 mgd) ^
TIAX FUWT tUILTt 1977 !
JCJkX OF HOST RECESI LTCRADE: .. !
Reportedly Beets BOD standard and occasionally exceeds SS standard.
RA.NXKG TABLE (PART 1) 1
RASXlilC
1
2
1
t
5
<
7
a
9
10
TAJIE MTEREDCE
C.2.C.3.
CAUSE
Aerator
<
,
I
POINTS
b
1
f
i
1
1
(
116
-------
APPENDIX E
PLANT EVALUATION SUMMARY
FOR
COMPREHENSIVE EVALUATION FACILITIES (PHASE II)
: The Plant Evaluation Summaries for plants where comprehensive evaluations
were conducted are included,in this appendix. The summaries include the rank-
ing of only:.the factors that were more severely affecting performance (i.e.,
those factors that received two and three points). The Plant Evaluation Sum-
mary Results for the Phase I comprehensive evaluations; have been previously
reported (5). . . . , . ...: .-....:
117
-------
IltXt TTIEI Conventional Activated Sludge w/Anaoroblc Digesters
MSICT nOVI 17,030cu a /day (4.5 Bgd)
ACTUAL TLOUl 12,700cu «/day (3.35 Bgd)
TEAX rtAXT BUILT: M76
YIAX OF MOST UCEXT UPGRADE! Hone
FIAXT mrOmjICE SUJKASt:" Plant effluent periodically violated
permit atandards.
RAKXIHC TABLE (FAST 1)
moausc
1
2
}
t
S
6
7
a
9
IP
TAiix IEFBIBKX
A,7,..3.
D.3,a.
C.2,f.
A.l.b.
CAUSE
Teitlnu to Process Control
Sludge Uaatlng Capability
Eaalliarlty Hith Plant Heads
POINTS
3
3
2
2
i
DESIOH FLOW: I060 cu in/dav fO.28 »«d>
ACTUAL FLOW: 795 cu n/day (0.21 B8d)
TEAR PLAOT BUILT: I975
TEAR OF MOST RECENT UPGRADE: So Upgrades
PLANT PERFORMANCE SUMMARY:
Llnlted historical monitoring data Indicates the final effluent has
net secondary standards. Reports of past solids loss and information
obtained during the survey indicate standards have been violated repeatedly
because of excessive solids discharged.
RANKING TABLE (PART 1)
RANKING
1
2
3
4
5
6
7
8
9
10
TABLE REFERENCE
C.2.f.
D.3.O.
A.l.b.
C.2.C.4.
C.l.f.
C.l.c.
C.2.C.2.
C.2.h.
D.l.c.
• D.3.b.
CAUSE
Sludge Wasting Capability
Testing to Process Control
Familiarity with Plant Needs
'Clarifier
Infiltration/Inflow
Industrial Loading
Process Controllability
Ultimate Sludge Disposal
Sewage Treatment Understanding
Technical Guidance
POINTS
3
3 '
2
2
2
2
2
2
2
2
APPENDIX E (Cont.)
PLANT HO. 051
nmt no. on
Page 1 of 5
Page 1 of 5
nAn TTHl Activated Sludge Extended Aeration
DtUCK TlOUt 2«0 cu »/day (0.075 mgd) . . .
ACTUL TLOUI 170 CM B/day (0.045 Bgd)
tux ru.fr tuiLTt 1954
ftAX Or MOST UO3(T UTCStADEI 1971
TLA.fr TDtr«ewic£ SB»IARY:
Plane uaually auecs cecondary treatment (peralt) atandards.
Oeeailoully soBft aolld* are unnecessarily loat to the effluent.
1
ULYKDiO
1
2
3
4
S
c
J
>
9
10
RANKING TABLE (PART 1)
IA9LE tUmUSCE
D.l.c.
CAUSE
Scvage. Treatment Understanding
POIIfIS
2'
1
f
PLANT TXPE: ^cm^.^ im'unn n»(J.f(m mi-t.
DESIGN FLOW: 1290 cu m/day (0.34 mud)
ACTUAL FLOW: 760 cu m/day (0.20 mgd)
TEAR PLANT BUILT: 1968
YEAR OF MOST RECENT UPGRADE: 1977
PLANT PERFORMANCE SUMMARY:
Plant has met standards on a consistent basis since upgrade.
RANKING TABLE (PART 1)
RANKING
1
2
3
4
5
6
7
8
9
10
TABLE REFERENCE
D.3.a.
D.l.c.
D.5.a.
CAUSE
Operator Application of Concepts &
Sewage Treatuenc.Understanding
Equipment Malfunction
POINTS
2
, 2
2
118
-------
PLANT TYPE: Contact Stabilization Activated Sludge
DESIGN FLOW: 568cum/dav (0.15 mad)
ACTUAL FLOW: 492 cu in/day (0.13 »gd) "
YEAR PLANT BUILT: 1967
YEAR OF MOST RECENT UPGRADE: None
PLANT PERFORMANCE SUMMARY:
Records of operation indicate BOD. and TSS monthly averages
fluctuate from about 25 mg/1 to 45 mg/1. The plant operator
also reported that excessive solids loss has occurred on a
somewhat regular basis for as long as he had been there, and
is not monitored in the above values.
RANKING
1
2
3
4
5
6-
7
8
9
10
RANKING TABLE (PART 1)
TABLE REFERENCE
D. 3.. a.
A. 1. b.
C. 2. g.
D. 3. b.
C. 2. c. 4.
A. 2. b. 5.
D. 5. a.
CAUSE
Operator Application of Concepts and
t-fl=HnE to Process Control
FamiHarity with Plant needs
Sludge Treatment
Technical Guidance
Clarifier
Safe Working Conditions
Equipment Malfunction
POINTS
T
3
2
2
2
2
PLANT TYPE: Two - Staae Activated Sludae
DESIGN FLOW: 3560 cu „ /(lav ((,,94 mcd)
ACTUAL FLOW: 2700 cu m /day (0.71 mad)
YEAR PLANT BUILT: 3975
YEAR OF MOST RECENT UPGRADE:
PLANT PERFORMANCE SUMMARY:
Plant occasionally violates discharge permit water quality
standards of 10 mg/1 BOD, 20 mg/1 SS, and 3 mg/1 NH3.
RANKING TABLE (PART 1)
RANKING
1
2
. 3 ,
4
5
6
7
8
9
10
TABLE REFERENCE
D. 3. a.
n i h
r ? f ?
CAUSE
Operator Acolication of Concents &
testinq to Process Control
POINTS
3
APPENDIX E (Cont.)
PLANT TYPE: Activated Sludge
DESIGN FLOW: 20,800 cu in/day (5.5 mgd)
ACTUAL FLOW: 20,400 cu m/day (5.4 ragd)
YEAR PLANT BUILT: 19«"
YEAR OF MOST RECENT UPGRADE: 1"6
PLANT PERFORMANCE SUMMARY; .
Plant historically exceeds BOD, TSS and ammonia limits, but met BOD^
and TSS limits during the survey.
RANKING
1
2
3
4
5
6
7
8
9
10
RANKING TABLE (PART 1)
TABLE REFERENCE
C.2.C.I.
C.2.5.
C.l.f.
D.3.0.
C.3.b.
C.2.C.2.
C.2.C.3.
~>
CAUSE
Process Flexibility
Sludge Wasting Capability
Infiltration/ Inflow
Tl!Hn!'t§PrrJceis0eontroiMePcs
-------
APPENDIX E (Cont.)
IVE3ICH FLOHl £1*n ,.„ ^Mpy n 7 «nr«)
ACTUAL FLOUt 4i?j r,, m,H»v n no rvH)
tUX TLUtT WILT] 1M, ,. \
«AX or MOST nEcnrr CKIIABE: „. ..^..^
mxr fnuronuscr. SUHMAKC:
Plant consistently meets secondary standards when not
bypassing, but ts being replaced to meet more stringent
strcaa standards and to correct I/I.
RA.-IKIKC TABLE (PART 1) 1
1AHXI8C
1
3
I
5
t
7
a
»
10
TA1LE REFERENCE
C.Z.C.l
CAUSE
Process FlnclMlltv
POINTS
•>•
. . | .
" i " ' '
f
1
f
I
! 1 — T — F i oT^ • '".'.'...'.'... .. \
DESIGN FLOW: 1320cu «/day (0.35 mgd) ' ' :*'
ACTUAL'FLOW: 1140cu iVday (0.30 Bgd) ' ' •• •
YEAR PLANT BUILT: 1975" ' ~ f .,,.,.-..
YEAR OF MOST RECENT UPGRADE: None ' ...... : ....,.-.
PLANT PERFORMANCE SUMMARY : - ... - - r
•Plant has not met TSS standards from cither -the polishing
ponds or from Che clariflers .about ,50 percent of the time.
, -- . ' t ' " < •
RANKING TABLE (PART^ 1)
RANKING
2
3' '
• 4 '
5
• -• 6 • •
' ' 7"
' ' 8 '
'9
- '10
TABLE' REFERENCE'
' ' D'.3.T>.
' ' • D.3.a'.
' ' f.i.C.l. '
• • ' • * CAUSE • • ' - •-»•-•
'Technical Guidance '
Testine Co Process Control
'Process F](u("fhJ H'fv
- " - '
' ' ' ' '
, POINTS •
- .3.-.
2 ' '
-. .2- - •
ILAKT TYPE: Activated Sludgo t'-'
StJlCHROWt 34.100.U a/day (9.0 wtd) ' " [r
ACTUAL FLOVi ZI.OOOcu sM»y (5.8 Bgd) ', ".'
1IM rUSI WILT: 19S7 " ......... j. ...
1UX OT HOST RECOT OTCRADE: 1976 ' ' ' f : '
mat ratreKXASCE SIMIARYI - • • • • - • • • • • , .: f •
Flaat hai MC atandarda conaiatantly. but has not operated at
optlaua.
RANKING TABLE (PART 1) , :
XAXKIM:
i
s
6
7
3
a
10
TABLE RETCMSCE
D.I.b.
' " CAUSE
Technical Guidance • > -
POlfiTS '
21
f
-T-f
•"1 "
' I ' '
' •[; ' •
"1 '
. . . j,
I
i
PLANT TYPE: Activated Sludse with Aerobic DiRcster. - . . . , ....
DESIGN FLOW: 1165 cu m/day (0.31 MGD) , , . - . - • • , ; • ; ; <
ACTUAL FLOW: 910 cu m/day (0.24 MGD) , . -, ^ T i. _ , ,
YEAR PLANT BUILT: 1965 ; • ' - . . .
YEAR OF MOST RECENT UPGRADE: None t : '.'.:'.'" f {,"• ' ' * '
PLANT PERFORMANCE SUMMARY : .- ' : * .-J M • { 'i '. t "
Consistent solids loss from plant due 'to uncontrolled sludge mass
and infiltration/inflow. ' •->•.,::• ' ' ' j ' j I "
RANKING TABLE (PART 1) - : : ,
RAHKING
1
2
4
5
6
7
8
9
10
TABLE REFERENCE
A.l.b.
C.l.f.
i C.2.C.3.
C.2.f .
CAUSE ! ; ,
Familiarity with Plant Needs
Infiltration/Inflow •
Operator Application or Concepts and
Aerator , . "
Sludge Wasting Capability
PpINTS
3 i
3 •
2 '•
< 2 -
1
i 4
-
120
-------
APPENDIX E (Cont.)
PLANT TYPE: - Activated Sludge- With Aerobic Dieester
DESIGN FLOW: 1590 -cu m/dsy (0.42 MGD) ,:..'.... . . , '
'ACTUAL FLOW: 950'cu m/day CO. 25 HGD) ,' - .
YEAR PLANT BUILT: . 1968 • • - .
YEAR OF-MOST RECENT UPGRADE: None ...
PLANT PERFORMANCE SUMMARY:
• Plant has historically 'violated permit requirements. Increased
operations has improved plant performance.
|
', ... . . _ RANKING TABLE (PART 1)
- RANKING
. . ,2
. . .3- .
, .It ,
5
... 6
7 "-
8
' 9
•10 •
TABLE REFERENCE •
• .0:2. h.: •••
• • • • C.2.£.
- • C.2.C.3.
. . CAUSE '.
OpeiaLLH AunllLdLlun uf Cuui.ii|jl.t and
Testing to Process Control •
Ultimate Sludge -Disposal •
Sludge Wasting Capability
Aerator ' ' • i - ....
- , I ,,,.,, . .
POINTS
-2- •
2
2 •
i
PLANT TYPE: Contact Stabilization/Trickling Filter .
DESIGN FLOW: 450 cu m/day (0.12 mgd) , ...
ACTUAL FLOW: 310 cu m/day (0.083 mgd).
YEAR PLANT BUILT: 1957
YEAR. OF MOST RECENT. UPGRADE: 1967 / ' '
PLAHT PERFORMANCE SUMMARY:
Plant effluent violates standards about '50 percent of the time.
RANKING TABLE (PART 1)
RANKING
• . 2. . .
3. . .
: - - *
' , 5. ,
. , 6,
7
. 9. .
10, .
TABLE REFERENCE
... ,.D.2.b.
A.2.b.5.
, . .CAUSE
Ot-eialui Auiillujuluil HI Ulivcepls and —
Process .Control, Testing . ,
Safe Working .Conditions
POINTS
*
2
, 2
PLANT HO. . 085
DESIGH FLOW:. .3700, cu m/day (0.98 n«d) •:'-':' . ' : ' :
ACTUAL FLOW: ,3530 cu m/day. . (0.93-medV . .. '. ' '' ' :
YEAR .PLANT BUILT:. , . , 1974 . _ . . : .
YEAR OF. MOST, RECENT UPGRADE: None : : .;
;PLANT PERFORMANCE SUMMARY: '• • - '
1 Plant has 'experienced occasional solids loss resulting in e
\ Permit violations.
1
1
RANKING TABLE (PART- 1) ' '-
RANKING
. .- 1 .
2
3
4
5
6
, 7.
. - .8 .
. .9
10
. TABLE REFERENCE,
D.3.a '-- - -
_
c.z.f. .'...;..
. A.2.C
D.3.b. ,,,,.,
*
CAUSE
Oberator Aoolication-of Concents and
Testing 'to Process Control
: Sludae Hastine Capability .
Productivity . : . . - .
. Technical Guidance .-.I ...
POINTS
3
3
.2
2
',
PLANT .TYPE: Activated Sludee Extended Aeration vith I/I bond,- -•
DESICH FLOW:. .3780 cu m/dav . „.„ „,,< -: . •. '. '. . . U . . - : . • . . . ; - ; . ; , .. ; •
ACTUAL FLOW: lyOju m/dax (0.48 med) .'.'.''. ~ '.', .'.'...',.- '•,.'. - . '• •
YEAR .PLANT BUILT:, . 1976 , -''._. 'I I .:.:. :..
YEAR.OF.MOST. RECENT UPGRADE: .. Bone , ; . •. . : ' ': ; : • .' - . ; ;; :
. PLANT PERFORMANCE SUMMARY: > , . ,
' Plant effluent quite often violated permit standards due tq^ -
excessive solids loss.
1 RANKING TABLE (PART 1) '
.RANKING
: , i .
. 2
' , , 3
. .4 ,
,5 .
. . .6 , .
• 7 . •
• 8
- -9
. . . 10 .
TABLE REFERENCE.
• -D.-3.a:
- D.3.b. • • • -
C.-2.f .•
C.2-.C.-2. • • •
; : CAUSE. 1 -, , ; . . , ;:.,-.'
, .Testing to Process Control.
Technical' Guidance' • ' 'f ' -
Sludee-Wastine Capability
Process Controllabilitir •
- POINTS -
. ..'...
3 ' '
• -3 - ' -
- ' -2 ' - "
- - 2 : -
121
-------
APPENDIX E (Cont.)
run in. on
TUn Tmi e»™,,,.«,,.,.l icMv.f,.,! Sludae with Carbon Filter.
&Z3XQI ITOVI 20,800 cu n/d*v (5.5 »sd>
ACTUAL nOVl 1
WAX run X>XLTt 1970 Primary Clarification
TIAX Or HOST MOOT ITCKADE: 1975 secondary Treatment
run rnuroKHAHCs SUKUKII ,[
Plant affluent froa carbon tover set plant's secondary treatment
•tandarda» but effluent froa secondary process would not have
Mt •taodarda.
BAHK1KC TABLE (FART 1}
IA.1XI.XC
I
2
1
*
S
<
7
a
9
10
TAILE XEFEREKZ
D.I, a.
CAUSE
Operator Application of Concepts and
Testing to Process Control
POIHTS
2
[
run no. o«
OEJICJI TLOUl 9500 cu a/dar (2.5 =sd>
ACTUAL fLOWt 4500 cu «/day (1.2 «sd> *
KIAX riAXt KIILTI 1949
WAX 07 HOST UCntT UTCHADE: ,9e6
TtM plant tta* B4C standards the najority of the tiae but not [
cenalstently.
I
luUncOG TABLE (PART 1)
Tuxnia
i
2
3
*
S
«
7
g
4
10
TABLE 11ZFEREBCE
C.2.H.3.
A.l.A.
C.J.P.I.
CAUSE
Aerator
Policies
Proecwfl FlMtiMHtv
ponrrs
3
2
9
1
DESIGN PLOW: 1B „„ cu m/dav f, B!,dl
ACTUAL FLOW: 8330 eu j,/dnv (2.2 modi
YEAR PLANT BUILT: 1976
YEAR OF MOST RECENT UPGRADE: „„„,
PLAST PERFORMANCE SUMMARY:
Permit requirements have been .violated since plant start-up. Effluent
quality does show Improvement during warmer months.
RANKING TABLE (PART 1)
RANKING
1
2
3
k
5
6
7
8
9
10
TABLE REFERENCE
C.2.C.3.
D.5.a.
CAUSE
Aerator
Equipment Malfunction
. .
POINTS
3
2
-
PLANT SO. .097
DESICH FLOW: 3785 cu m/day (1.0 mgd)
ACTUAL FLOW: 3400 cu m/day (0.9 »Bd)
YEAR PLANT BUILT: 1975
YEAR OF MOST RECENT UPGRADE: Hone
PLANT PERFORMANCE SUMMARY:
Violated standards periodically.
RANKING TABLE (PART 1)
RANKING
1
2
3
4
S
6
7
8
9
10
TABLE REFERENCE
D.3.a.
C.l.f.
D.2.b.
CAUSE
Operator Application of Concepts and
Infiltration/Inflow
Process Control Testing
POINTS
3
3
2
'
122
-------
APPENDIX F'
DESIGN INADEQUACIES OBSERVED
The following design problems were identified during the evaluation of 98
facilities for both Phase I and II of the project. Problems listed have cre-
ated unnecessary or excessive maintenance, difficult process control, inaccu-
rate or excessive sampling and decreased performance.
PLANT LAYOUT
FLOW MEASUREMENT
BAR SCREENS
COMMINUTORS
GRIT REMOVAL
PRIMARY CLARIFIERS
AERATION BASINS
AERATORS
TRICKLING FILTERS
ABF TOWERS
FINAL CLARIFIERS ,
RETURN SLUDGE FLOWS
POLISHING PONDS
CHLORINATION
WASTING CAPABILITY • ...' " '! ..
SLUDGE HOLDING FACILITIES
AEROBIC DIGESTERS
ANAEROBIC DIGESTERS .......
SLUDGE DEWATERING & ULTIMATE DISPOSAL
LABORATORY FACILITIES
MISCELLANEOUS ;'.. .'..'.'.'.'_'...'.;.' '"' '_. "."•.'_'„':".
123
-------
APPENDIX F (Cont.)
PLANT LAYOUT ! ; ..
- Lack of interconnection requires operation of three separate activated
sludge plants as one facility
- Covered basins prevent observation of processes
| . • ' : ' '. .-.;'.'• :;.' .=-.-.'•?•.:. •
- Return sludge air compressors jare located outside and repeatedly break
down
- Plant with multiple units not having the flexibility to operate as
parallel plants !.. .'.•>•,•: *.>•..
- No flow splitting flexibility jto parallel plants
— Bar screen located downstream from comminutor
- Freezing of influent sampler located outside
- Plant location inaccessible during inclement weather
— Excessive compressor noise • ....."•• '::•.-•• ,•£"-<•
- Disinfection before polishing pond • . ' _ -• .-. ;i,-.-:i., .
i
- Parallel secondary treatment units not capable of being operated as: one
facility :
- Inadequate piping flexibility required shut down of one trickling;-filter
if one clarifier is down I
- One scraper drive for primary and final clarifiers requires operation of
both when operation of one is desired - ' : j .
- Lack of bypasses on individualjtreatment units, like aeration basin,
trickling filter, etc. i
- Overflow from septic tank to plant effluent
i ' • .: •:••
- Both trickling filter and activated sludge processes in very small plant
causes excessive operational requirements • • - : •
i ' -'' •" "'
FLOW MEASUREMENT - •! , , . ;
- Discharge through a pipe rather than the control section for which the
recorder is designed • ... _„ ,; - .... ... . , -;»r,;
l
- Downstream channel slope and geometry causes backup in Parshall flume
throat ! .
124
-------
APPENDIX F (Cont.)
- Parshall flume oversized
- Flow measurement inaccurate due to upstream barminutor placement
- No flow recorder
- Excessive upstream velocity causes turbulent flow through Parshall
" flume. :
- Control section not accessible for inspection and maintenance
- Level transmitting instrumentation not compatible with level receiving
instrument
- During high river flows, Parshall flume on effluent submerged
- Flow recorder not calibrated
- Recycle flows (cooling water) included in plant flow measurement
- Roll-up flow chart requires removal to observe flow for more than the
preceeding four hours
' - Wires crossed in totalizer, resulting in wrong reading M
•M- Flow measurement riot adequately showing flow variations . - . ; •„
— Humid influent structure causes problem with moisture sensitive level
sensor/: '. ." •.-. -'.'•'. v ,'. • ' :'•:•'*: •<•- ;. ••.: .*-•.'• ••:."••• -••: >•_ .:_i:, • •. -.-;
- Flow velocity too high in Kennison nozzel
- Liquid level sensing float freezes • '•'• '- • " ' :' " ;f , ; ••;«=:•':
— Downstream'bar'screen backs flow into flume throat-'as 'screen plugs
— Control section as overflow from aerated grit chamber
BAR SCREENS . >
— Bar spacing too narrow : •••" ' - '-"•'."'- "• '.•'"•' --..-'•• " r^:/f :
- Backed up flow released after cleaning causes hydraulic surges through •
aeration basin and into clarifier
— Freezing problems with mechanical bar screen located outside- ; ""
125
-------
I APPENDIX F (Cont.)
COMMUNITORS
- Bent teeth, no protective bar screen
- Plugging with rags
'•* ' '. .' ..•'/"'•
- Repeated mechanical failure of hydraulic drive type comminutor
GRIT REMOVAL ,
- Excess wear on grit screw center bearing because of exposure to grit
I
— Odors from organics settling out in grit channel , .
i • '
- Pump discharge to grit chamber jiirected at grit buckets, and washes grit
from buckets . . . . ,
- Grit auger not functional
- Grit auger too low for disposal; in truck
PRIMARY CLARIFIERS
- Overloaded by excessively large] trickling filter humus return pump
- Overload due to trickling filter recirculation through primary clarifier
I ! >"'.''
- Improper placement of valve limits scum pumping
- Short-circuiting due to inlet baffle construction
- Preaeration in center of clarifjier reduces effective clarification area
AERATION BASINS
- Pipe outlet plugs with rags
- Lack of piping to operate as conventional, as well as step load or
contact-stabilization activated!sludge ,• : ,
I
- Receives hydraulic surges when jthe bar screen is cleaned
i , .
I
- Receives hydraulic surges from oversized return pump on time cl.ock
. i . ",•.-. ...',,.
- Loss of solids due to flooding .
- No bypass to final clarifier
126
-------
APPENDIX F (Cont.)
- Action of aeration rotors and revolving bridge and configuration of basin
creates swells and voids which result in wave-like stresses on bridge
- Leakage betwen contact and reaeration basins due to moveable wall design.
- No wall between contact and reaeration areas .
AERATORS
- Surface mechanical aerators overheat and shut off under increased flows
due to I/I
- With floating aerators, repeated breaking of cables when operated on
intermittent basis
- With submerged turbine aerators, repeated down time due to bearing and
shaft failure
- Inadequate freeboard for splashing with surface mechanical aerators
- Icing problems with surface mechanical aerators
- Rag accumulation on surface mechanical aerators
- Inadequate dissolved oxygen control
TRICKLING FILTERS
- Recirculation only through primary clarifier
- Inadequate capacity of trickling filter arms
- Leaking distributor seal causing ponding and short-circuiting
- Poor flow splitting to trickling filters
ABF. TOWER
- Undersized pipe carrying tower underflow back to recirculation tank
- No flexibility to vary percent tower underflow returned to recirculation
tank
- Sludge return and tower recycle flow are directed into the same pipe
which limits their volume recycled ..-..., : :
FINAL CLARIFIERS , , .:;-;...,,
- Poor flow splitting to clarifiers
127
-------
APPENDIX F (Cont.)
i
i
- Poor development of surface area with weirs
— Sludge scraper mechanism directing counter-current to wastewater flow
; , . ' ^ ;' . f " • i ''"
— Hydraulicly connected clarifiers not of the same elevation causes unequal
flow splitting ' ' '" 'J ' *
- Freezing during cold weather
-, : '• - '.','..*.''
\ ' ' •
- Inlet and outlet on circumference, a large diameter, large design'bver-
flow rate, and failure to consider process recycle flows caused problems
with hydraulic washout of solids.
- Floating trash returned to aeration basin, no ultimate disposal of* scum
- Combined primary and final clarifier unit allows mixing of two with
scraper mechanism ; :
..
- Hydraulic restriction causes submerged overflow weirs
- Short-circuiting due to inlet baffle construction ' ;
- Placement of trickling filterirecirculation draw-off, overloads final
clarifier - '•' ' ' '' '• <-•'"•" ;;•: -;•.. ••' •"- "
i
- Weirs on single launder not balanced to pull evenly-from each1 side
: ' ' • .'", ° ':;'„'-;..; ::• :• '>-. -".;{:•
- No skimming device
RETURN SLUDGE FLOWS : '. , ^ :.
— Constant speed centrifugal pumps used, difficult to adjust flow • ; -!;
- Return sludge flow not visible at any point . ..,-,.- -
— No measurement ; ; ' • ;?- '--'• -''••'•'• "••
i
— With multiple clarifiers, balancing return flow was difficult : ' "
- Variable speed return pumps that were too large even at the" rpw'est
setting : r : ,r
- Plugging of telescoping valves at lower flows " "'!}
i -.„.-..
— With multiple clarifiers, asyraetrical piping causes imbalance1 of return
sludge flows
- Sludge returned to a point near the outlet of the aeration basin ' "
128
-------
APPENDIX F (Cont.)
- Valve controlling air to air lift returns is shut-off type, not
regulating type
- Measurement with 90° V-notch weir not sensitive enough
— Oversized pump draws down final clarifier, then hydraulically overloads
aeration basin
- Waste piping and appurtenances requires excess return rate to accomplish
... wasting:- ..... _-;;. .... . ;,,;,. • _; _.• -. .;•.--_• ;-; .-•;.. - . :,.;;';:: ...; ;! ;-. ;••[ -
- Stilling box ahead of V-notch weir too, small ,: .'•..•'
\ '•
tr Location , of return; measurement requires pperator to walk, out on narrow
wall over basins :
- Sludge return from clarifiers controlled by plug valve into wetwell.
Excess operator time required to match variable speed pump with valve
controlled rate-. .. ..,.- • > , ••-;•;>••; :;-» •-.',; -•.; •-<:••• '-.••.-.• :. ;-:;'. .-••-• ••::::;:•-
— Return adjustment requires alternate, operation of pump from, first clari-
fier, second clarifier and both clarifiers to set desired total return
- Plugging of ball valve used "for return control t r_ ^ :
— When return channel oyerf lows, . it overflows to the clarif ier--as, well as
the aeration basin due to channel construction
s'.iiTj'1: %,-::'. •••;•;'. i./,^ ^;.; ••
- Partial plugging with rags of butterfly valve used for return sludge flow
control ' •.• t;,::> r.'L...!" •..;.• V. I HP
POLISHING PONDS v.::;; ., /- ;
- No pond bypass ; ,
- Sludge wasted to polishing pond
- Pond located- after disinfection.
- All ponds .noted to contain large amounts ojE sludge,<. some, of which;was-
being discharged s -.-":!•:•:•
CHLORINATION , .. . : -.,..-....-. •;.<,--. :-:^-;. \t «. 1 .•; -?~'.v;^;:H -
,~- Chlorine,diffuser..located at center pjE contact tank rath,err than .at;-the
inlet - i
- Chlorine diffuser located at outlet of contact tank
129
-------
APPENDIX F (Cont.)
- Rotometer on chlorinator too large for present application
- Poor mixing
I .
- Chlorine dosage paced by effluent flow, but filter backwash water removed
from combined contact-backwash storage tank shuts off: chlorination,until
it is again filled and discharging
..-•••••••.•
- Inadequate contact time in outfall pipe
- Inadequate chlorination in fin'al clarifiers
- No depth control device on contact tank results in inadequate contact
time and short-circuiting ; . :
- Short-circuiting over baffles'during high flows •
- Short-circuiting due to inlet design
- Residual chlorine analyzer for' automatic adjustment of chlorine feed rate
never worked \ ;
WASTING CAPABILITY , ' : .:.:-: ;; : : :• =: .
— No digester or sludge Tiolding facility," inadequate drying bed-s- f
i
- Down time of exotic sludge treatment facility causes inadequate wasting
- Wasting capability only from mi.xed liquor requires excessive waste volume
i
- Insufficient capacity . ' j : . ; •'••'!••-.• >.;-I :£ :-. -•,<, F;>; , '. \ -
- Sludge lagoons undersized
- No measurement
- None provided i ' ' ' •'•'."'';'• :'; -
- Partial plugging of waste pump prevents use of pumping rate to calculate
waste volume
- Valve choice for directing return sludge to waste requires excess
operator time ! . !; :
- Undersized waste pump , " ,;
SLUDGE HOLDING FACILITIES ; ; : ;^ . :
- Odors from unaerated, uncovered sludge storage . : *'-.
130
-------
APPENDIX F (Cont.)
- Potential gas build-up problem with covered, unaerated sludge storage
AEROBIC DIGESTERS
- High groundwater and pressure relief valve prevents batch operation
- Inadequate air supply
- Inadequate supernating flexibility
- Undersized
-- , - , *
- Pump used for sludge removal prevents thickening of sludge
- Small digesters and minimum freeboard make foam containment difficult
- Freezing problems •••;-. , '
- Common wall;with aeration basin structurally insufficient to allow batch
operation
t . .
- Provide with automatic supernating device which does not work
ANAEROBIC DIGESTERS - k ..,-. ;, •-. , > -!. M ; •• si :•: ," t ;
- Inadequate supernatant draw-offs , : :
-With multiple units j, inflexibility to, waste to desired primary digester
- Plugging problem between bottom of primary digester and second-stage
digester
: • • ! •;* i.V .;!,•; :;,'••.- .":-:- '
- Water seal on recirculation pump loads digester with cold water
- Sludge pumping line from clarifier plugs which prevents digester loading
at concentrations above about six percent . n :_ ; :!:
;- No gas meters.. ..":, ' ' • ! .•-.•.•:•:•• ..-...;- '•<••. ..•,; '-.;. -;M • ,^j .• :•• ,.;-,• /-: -
- No mixing ,
- Uneven loading due to breakdown of time clock ~ ' > r
- Temperature drop due to failure of automatic firing mechanism on boiler
- Cold digester produces poor supernatant :'. ;-. ;"•,,.;,; ..•;' • _ t >
— Leaky cover requiring down time for, repair :. :, r;; .T, : . "' :i; •
131
-------
! APPENDIX F (Cont.)
- Single gas meter for two digesters \
— Uninsulated heating pipes outside
'_'•'":, ' <
SLUDGE DEWATERING & ULTIMATE DISPOs|L
.
- Truck ramp too steep for; use during win:te;r; : . ;;f '<.•,
- Repeated maintenance on sludge j in;cineration}facili;ties( . .;« ; •;; y,r'•','.
- Insufficient sludge drying lagoons • .',.,.'..'.'..'.'.'.'.'... ..,...'...1,.1..;""!.';•.."..., '.".,.
- Disposal of sludge in polishing lagoon ' ; ; ' l ','^':,
- Truck capacity too small ,;.,...,.,
- Insufficient drying beds • --• -••'•• -:........-- , ,'.C:,:;,i.
- Drying bed.subnatant line crushed by construction equipment. .
- Land application n&t possible, during certain times of the. year - no
alternate disposal or storage
LABORATORY FACILITIES . ,;s .. :i ::'<.,•.: H ^-!
- Vibrations prevent use of scale 'it; -i j ! -" ..«
-------
APPENDIX G
WASTEWATER TREATMENT COST INFORMATION
TABLE G-l. (1 of 1) COST INFORMATION FOR 0-380 CU M/DAY
SUSPENDED GROWTH FACILITIES - PHASE II
PLANT IDENTITY
FLOW (ragd)*
CATEGORY
Salary
Utilities
Supplies '.•*.
Chemicals
Transportation
Training & Education
Miscellaneous
$
4951
3974
1000
291
18
0
2230
,052
0.045
-------
APPENDIX G (Cont.)
TABLE G-2. (1 of 1) COST INFORMATION FOR 0-380 CU M/DAY (0-0.1 MGD)
FIXED FILM FACILITIES - PHASE II
PLANT IDENTITY
FLOW (mgdj)*
069
0.08
CATEGORY
$71000
GAL.
Salary I 7987 27.4
Utilities 840 2.9
> >
Supplies 75 0.3
Chemicals \ 650 2.2
Transportation! 100 0.3
Training & Education 24 0.1
\
Miscellaneous 150 0.5
Operations Subtotal 9826
33.7
Capital Outlay;
0
Total
9826
33.7
*mgd x 3785 = cu m/day
134
-------
APPENDIX G (Cont.)
TABLE G-3. (l of 4) COST INFORMATION FOR 380-3800 CU M/DAY (0.1-1.0 MGD)
SUSPENDED GROWTH FACILITIES - PHASE II
PLANT IDENTITY
FLOW (mgd)*
CATEGORY
Salary
Utilities
Supplies
Chemicals
Transportation
Training & Education
Miscellaneous
$
6200
5600
500
500
300
0
500
051
0.21
£/1000
GAL.
8.1
7.3
0.6
0.6
0.4
0
0.7
$
5260
5500
800
1800
200
300
100
062
0.20
$/1000
GAL.
7.2
7.5
1.1
2.5
0.3
0.4 -
0.1
$
6900
2400
1000
300
500
300
0
065
0.13
t/iooo
GAL.
14.5
5.1
2.1
0.6
1.1
0.6
0
Operations Subtotal 13600
Capital Outlay
8900
17.7
11.6
13960
6675
19.1
9.1
11400 24.0
0 0
Total
22500
29.3
20635
28.2
11400 24.0
*mgd x 3785 = cu m/day
135
-------
APPENDIX G (Cont.)
I
TABLE G-3.~(2 of 4) COST INFORMATION FOR 380-3800 CU M/DAY (0.1-1.0 MGD)
SUSPENDED GROWTH FACILITIES - PHASE II
PLANT IDENTITY
FLOW (ragd)*
CATEGORY
Salary
Utilities
Supplies
Chemicals
Transportation
$
39060
43000
1280
9000
830
Training & Education 1520
Miscellaneous
Operations Sub-
total
Capital Outlay
Total
24688
119378
30000
149378
066 '
0.71
t/lOOO :
GAL.
15.1 ;
16.6
0.5 !
3.5 !
0.3
0.6
9.5
46.1
11.6
57.7
$
34700
31200
5600
2800
800
800
5500
81400
38800
120200
074
0.30
<(71000
GAL.
31.7
28.5
5.1
2.6
0.7
0.7
5.0
74.3
35.4
109.7
-
$
3800
8806
2637
0
0
0
1245
16488
8840
25328
077
0.24
•IViooo
GAL.
4.3
10.1
3.0
0
0
0
1.4
18.8
10.1
28.9
*mgd x 3785 - cu m/day
136
-------
APPENDIX G (Cont.)
TABLE G-3. (3 of 4) COST INFORMATION FOR 380-3800 CU M/DAY (0.1-1.0 MGD)
SUSPENDED GROWTH FACILITIES - PHASE II
PLANT IDENTITY
FLOW (mgd)*
CATEGORY
Salary
Utilities
Supplies
Chemicals
Transportation
Training & Education
Miscellaneous
$
4260
1350
400
0
0
500
600
080
0.25
t/iooo
GAL.
4.7
1.5
0.4
0
0
0.5
0.7
$
25831
12236
2950
2000
0
75
2790
085
0.84
$71000
GAL.
8.4
4.0
1.0
0.6
0
0.02
0.9
, $
18880
15000
1250
1250
800
0
3650
086
0.48
$/1000
GAL.
10.8
8.6
0.7
0.7
0.5
0
2.1
Operations Subtotal 7110
7.8
45882 15.0
40830 23.4
Capital Outlay
6670
7.3
28927 9.4
14500
8.3
Total
13780 , 15.1
74809 24.4
55330 31.7
*mgd x 3785 — cu m/day
137
-------
APPENDIX G (Cont.)
TABLE G-3. (4 of 4) COST INFORMATION FOR 380-3800 CU M/DAY (0.1-1 MGD)
SUSPENDED GROWTH FACILITIES -PHASE II
PLANT IDENTITY
FLOW (mgd)*
CATEGORY |
i
Salary
Utilities
Supplies
Chemicals
Transportation
$
74900
25700
6000
5300
950
Training & Education 675
Miscellaneous
300
097
0.84
"t/1000
GAL.
24.4
8.4
2.0
1.7
0.3
0.2
0.1
Operations Sub- 113825 37.1
total ',
Capital Outlay i 33900 11.1
Total
147725
48.2
*mgd x 3785 = cu m/day
•138
-------
APPENDIX G (Cont.)
TABLE G-4. (l of 2) COST INFORMATION FOR 3800-38,000 CU M/DAY (1.0-10.0 MGD)
SUSPENDED, GROWTH FACILITIES - PHASE II
PLANT IDENTITY
FLOW (mgd)*
CATEGORY
Salary
Utilities
Supplies
Chemicals
Transportation
$
96368
41800
2257
1500
0
Train5.ng & Education 505
Miscellaneous
Operations Sub-
total
Capital Outlay
Total
5774
148204
82587
230791
038
3.14
t/iooo
GAL.
8.4
3.7
0.2
0.1
0
0.04
0.5
12.9
7.2
20.1
$
245200
50400
43300
5100
8500
1200
14500
368200
77100
445300
068
5.4
-------
APPENDIX G (Cent.)
TABLE G-4 (2 of 2) COST INFORMATION FOR 3800-38,000 CU M/DAY (1.0-10.0 MGD)
SUSPENDED GROWTH FACILITIES - PHASE II
PLANT IDENTITY
FLOW (mgd)*
092
3.12
CATEGORY
$
t/1000
GAL.
Salary j 373700 32.8
Utilities 79000 6.9
Supplies 153500 13.5
Chemicals 65000 5.7
Transportation | 12500 1.1
Training & Education 500 0.04
Miscellaneous i 2000 0.2
Operations Subtotal 686200 60.3
i
i
Capital Outlay : 83250 7.3
I
Total 769450 67.6
*mgd x 3785 - cu m/day
140
-------
APPENDIX G (Cont.)
TABLE G-5. (1 of l) COST INFORMATION FOR 3800-38,000 CU M/DAY (1.0-10.0 MGD)
FIXED FILM FACILITIES - PHASE II
PLANT IDENTITY
FLOW (mgd)*
070
1.1
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA.-600/2-80-129
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
EVALUATION, OF OPERATION AND"MAINTENANCE FACTORS LIMITING
MUNICIPAL WASTEWATER TREATMENT PLANT PERFORMANCE
Phase II
5. REPORT DATE
August 1980 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S) ~".
Bob A. Hegg, Kerwin L. Rakness, James R. Schultz,
and Larry D. DeMers
8. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORGANIZATION NAME AND ADDRESS
M&I Inc., Consulting Engineers
4710 So. College Avenue
Fort Collins, Colorado 80525
10. PROGRAM ELEMENT NO.
A36B1C
11. CONTRACT/GRANT NO.
68-03-2572
12. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research Laboratory—Cin.,0H
Office of Research and Development .
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final, Oct. 1977 - Apr. 1979
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
Project Officers: John M. Smith (513-684-7611) and
Francis L. Evans, III (513-684-7610)
See also EPAr600/2-79-034, 035, 078 Phase I
Ifany dl^the country's wastewater treatment plants do not meet design expectations and
NPDES permit standards. A research project was initiated to identify, quantify and
rank the causes of this poor performance by comprehensive evaluations of 50 plants in
nine western states. The identified highest ranking causes of limited plant perfor-
mance reflect an inability of in-plant personnel to optimize process control and the
performance of existing facilities. Deficiencies in design features also ranked high.
The performance of each plant is typically limited by a unique combination of problems
which require individual identification and elimination. The Composite Correction
Program (CCP) was introduced and demonstrated. This approach to improving the perfor-
mance of existing facilities was conducted at selected facilities. Areas of special
evaluation include aerator and clarifier design, sludge production,in activated sludge
plants, aerobic digester operation, reference materials used in treatment plants,
operator time and tasks before and after a CCP, and the effects of toxic substances on
well-operated treatment facilities.
This report was submitted in partial fulfillment of Contract No. 68-03-2572 by M&I, Inc
under the sponsorship of the U.S. Environmental Protection Agency. This report covers
*he period October 1, 1977 to April 1, 1979 and the work was completed November, 1979.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Waste Treatment: Activated Sludge Processes
Trickling Filtration, Settling Basins
Wastewater: Water Pollution
Treatment plant performan
Improving plant performan
Factors causing poor
plant performance
Composite Correction
Program'(CCP)
Operation, Design, Mainte
nanrp
:. DISTRIBUTION STATEMENT
Release to public
. SECURITY CLASS (ThisReport)'
Unclassified
21. NO. OF PAGES
16.0
20. SEC.URI
CURITY CLASS (Th,
Unclassified
'is page)
22. PRICE
EPA Form 2220-1 (9-73)
159
U.S. GOVERNMENT PRINTING OFFICE: 1980--657-165/0133
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