United States
Environmental Protection
Agency
Permits
Division
Office of
Water Enforcement
Washington D.C.
Estimate of Effluent
Limitations to be Expected
•
from Properly Operated and
Maintained Treatment Works
-------
ESTIMATION OF EFFLUENT LIMITATIONS
TO BE EXPECTED FROM PROPERLY
OPERATED AND MAINTAINED TREATMENT WORKS
by
Daniel J. Hinrichs
Culp/Wesner/Culp - Clean Water Consultants
P. O. Box 40
El Dorado Hills, California 95630
Under
Contract No. 68-01-4329
Project Officer
Jim Grafton
U.S. Environmental Protection Agency
Permits Division
Office of Water Enforcement
Washington, D.C. 20460
-------
DISCLAIMER
This report has been reviewed by the Office of Water Enforcement,
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 commercial products constitute endorse-
ment or recommendation for use.
-------
PART 1
CONTENTS
Figures 11
Tables iii
Acknowledgements iv
1. Introduction 1
2. Purpose 2
3. Description of Manuals 3
4. Background Theory and Data Sources 6
User Instructions 27
-------
PART 1
FIGURES
Number Page
1 Estimated Removals of Suspended Solids and BOD in
Primary Basins at Various Hydraulic Loadings . . 9
2 Trickling Filter Performance BOD Effluent Concentration ... 14
3 Trickling Filter Performance Effluent Suspended Solids .... 15
4 Conventional Activated Sludge, BOD 19
5 Conventional Activated Sludge, Suspended Solids 20
6 Extended Aeration, BOD 21
7 Extended Aeration, Suspended Solids 22
8 Contact Stabilization, BOD 23
9 Contact Stabilization, Suspended Solids 24
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PART 1
TABLES
Number page
1 Primary Plants Visited 7
2 Primary Plant Data Summary 8
3 Trickling Filter Plants Visited 13
4 Trickling Filter Visitation Data Summary 16
5 BOD Removal Reliability 17
6 Suspended Solids Removal Reliability 17
7 Conventional Activated Sludge - Plants Visited or Plants
Whose Monthly Data Were Obtained From State Environmental
Offices 25
8 Contact Stabilization Plants Visited 26
9 Extended Aeration Plants Visited 26
iii
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ACKNOWLEDGEMENTS
This manual and the two accompanying manuals were prepared by
Culp/Wesner/Culp (CWC) for the U.S. Environmental Protection Agency,
Office of Water Enforcement, Washington, D.C. under Contract Number
68-01-4329 as directed by Mr. Jim Grafton, project officer.
Data were collected at several locations throughout the country
with the assistance of several state and EPA offices as well as the
operating agencies. The list below shows those offices who provided
operating information. Considerable data were taken from other pro-
jects in progress by CWC.
Agencies Contacted
1. U.S. EPA, Kansas City, Kansas, Office of Surveillance and Analysis
2. U.S. EPA, Kansas City, Missouri, Office of Water Enforcement
3. Iowa Department of Environmental Quality, Region 1, Manchester, Iowa
4. Wisconsin Dept. of Natural Resources, Div. of Environmental
Standards, Madison, Wisconsin
5. Neillsville, Wisconsin
6. Sun Prairie, Wisconsin
7. Stanley, Wisconsin
8. Cross Plains, Wisconsin
9. Mazomanie, Wisconsin
10. Adams, Wisconsin
11. Rockdale, Wisconsin
12. Colby, Wisconsin
13. Spencer, Wisconsin
14. California State Water Resources Control Board, Water Quality
Division, Sacramento, California
15. Seaside, California
16. Gilroy, California
17. Santa Cruz, California
18. Pacific Grove, California
19. Watsonville, California
20. Santa Cruz County, California
iv
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21. San Diego County, California
22. Laguna Beach, California
23. Shellsburg, Iowa
24. Center Point, Iowa
25. Monticello, Iowa
26. Cascade, Iowa
27. Manchester, Iowa
28. Independence, Iowa
29. Georgia Dept. of Natural Resources, Environmental Quality
Division, Atlanta, Georgia
30. U.S. EPA, Atlanta, Georgia, Office of Water Enforcement
31. College Park, Georgia
32. Atlanta, Georgia
33. Athens, Georgia
34. Cobb County, Georgia
35. Leominster, Massachusettes
36. Hampton County, Massachusettes
37. City of Westboro, Massachusettes
38. Nassau County, New York
39. Richmondville, New York
40. Athens, New York
41. Elmhurst, Illinois
42. Homewood, Illinois
43. Harrington, Illinois
44. Wooddale, Illinois
45. Addison, Illinois
46. Carpentersville, Illinois
47. Toledo, Oregon
48. Salem, Oregon
49. Gig Harbor, Washington
50. Sedro Wooley, Washington
51. Arlington, Washington
52. Massachusettes Dept. of Environmental Quality Engineering,
Boston, Massachusettes
53. New York Dept. of Environmental Conservation, Albany, N. York
54. Illinois Environmental Protection Agency, Springfield, Illinois
-------
55. Oregon Dept. of Environmental Quality, Portland, Oregon
56. Washington Dept. of Ecology, Olympia, Washington
VI
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SECTION 1
INTRODUCTION
There are a large number of municipal wastewater treatment plants
that will be unable to comply with the legislatively mandated minimum
secondary treatment requirements due to the lack of available funding.
The intent and purpose of the 1972 Federal Water Pollution Control Act
Amendments will be met when a municipality that is unable to finance
capital improvements, unassisted, operates and maintains its existing
facility to minimize the discharge of pollutants.
Since time and resources are unavailable to visit and examine every
facility, a simplified screening procedure has been developed to estab-
lish effluent limitations considering the type of process and actual
plant loading as related to the design loading. This loading relation-
ship (normalized flow) is defined in this study as the ratio of actual
flow to design flow. The developed procedure is designed to provide
estimates of the expected effluent 6005 and suspended solids concentra-
tions given the actual plant flow and design capacity. Operation and
maintenance requirements for plants from .01 to 10 mgd were also developed
to provide an estimate of the appropriate effort required by the owner to
meet expected plant performance.
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SECTION 2
PURPOSE
The purpose of this project is to provident!. S. [Environmental [Pro-
tection Agency regional staffs with a necessary documented method for
establishing effluent limitations for unfunded, publicly owned treat-
ment works. This method will provide a means of screening out facilities
that are apparently not being operated and maintained at a level of effort
necessary to achieve optimum performance. Those facilities that are
screened by this process will require further review to determine the
cause of inadequate performance. This method will not provide a means
for determining whether the lacfc of optimum performance is due to in-
adequate operator skill, inadequate design, poor construction or addition
of or lack of control of high strength industrial waste.
The following screening method is proposed to provide a rapid means
of reviewing and issuing NPDES permits to a large number of applicants.
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SECTION 3
DESCRIPTION OF MANUALS
This document consists of 3 parts. Part 1 describes the development
and data sources as well as the use and limitations of the user manuals.
Parts 2 and 3 each consist of a user manual. One manual was developed
for determining effluent limitations (Part 2) and the other for determin-
ing operation and maintenance requirements (Part 3). The effluent limi-
tations manual was developed to provide a reviewer with information
necessary to predict expected unit process performance in terms of BOD5
and suspended solids concentrations. The main premise used is that the
plant was properly designed and constructed and that there are no major
pieces of equipment that are inoperable. In other words, the unit pro-
cess should meet design standards until the actual flow exceeds design
flow. This manual is intended mainly for plants of less than 10 mgd
flow. When the actual flow exceeds design flow, the effluent quality or
constituent removal efficiency should decrease as predicted by the curves.
Good operational control can provide better than predicted performance.
With these performance curves, overloaded plants can be issued interim
permits until plant expansion can be completed. If a facility does not
meet the performance indicated by the curve for its unit process type,
then further investigation is necessary.
The second manual provides operation and maintenance requirements
information. Tables are provided to show labor hours, electrical energy
consumption, chemical costs (mainly chlorine) and maintenance material
costs (spare parts, replacement equipment, etc.). A unit labor cost
(including fringes) of $9/hour and an electricity cost of 3.0£/kwh were
assumed to determine the total annual operation and maintenance costs
shown on the figures for the various unit processes. The costs were
first computed for plants operating at design capacity or at a normalized
flow equal to 1.0. The tables and figures are then adjusted to show
additional operation and maintenance costs due to overloaded conditions.
The purpose of this approach is to provide guidance as to the necessary
operation and maintenance cost to attain the effluent standards or re-
movel efficiencies presented in the effluent limitations manual.
Unit process types and size ranges were selected based on data
sources available through the U.S. Environmental Protection Agency
"Needs Survey" and "Storet" programs. Unfortunately, some states'provided
less thorough information than others. There was also some confusion as
to the proper category for certain modifications of activated sludge.
For example, should contact stabilization be counted as activated sludge
or as "other".
-------
The predominant processes were primary, trickling filter, and
activated sludge. Stabilization ponds or lagoons were eliminated due
to the change in regulations, in that a 30 mg/1 suspended solids effluent
concentration is no longer required. As of this date, new standards
have not been set. The various data sources failed to show numbers of
package plant systems of the activated sludge type. Since most activated
sludge systems smaller than 1 mgd will normally be more economical to
operate and maintain if designed as package plants - extended aeration or
contact stabilization, or as oxidation ditches, these categories were
included.
The 1976 needs survey has just been completed. This survey differs
from the 1974 survey in that a private contractor compiled data rather
than the individual states. Details of this survey have not yet been
published. However, there are some bits of data that are available and
are applicable to this project. Based on the 1976 needs survey, 8,571
plants of 16,000 existing plants will not meet secondary treatment stan-
dards (30 mg/1 BOD5/30 mg/1 suspended solids) by July 1, 1977. This fact
shows the necessity of this project. Previous data from both "STORET"
and the 1974 Needs Survey, although having some minor differences in
inventories, show less than 3% of the treatment plants with existing
flows greater than 10 mgd. The 1976 needs survey data show that over one
half of the treatment plants in the United States have less than 0.1 mgd
of flow. Thus, the flow ranges used for this study were chosen for less
than 10 mgd. Processes where applicable are shown at capacities as low
as 0.01 mgd. Some process types are not available for flows less than
0.1 mgd.
An effort was made to categorize plants by age or "flow age". Flow
age is defined as the total gallons of flow having been treated by a
facility. This results in a measure of the time that a plant has been
operating at a relatively high flow rate. Unfortunately, records were
not available or accurate enough to determine this parameter. Several
plants were visited that had been built prior to 1950 but most mechanical
equipment had been replaced several times since. A good example of this
situation (although this example was not part of the study for the manual)
is the City of Los Angeles Hyperion wastewater treatment plant. The
primary sludge pumps were originally manufactured before 1930. Replace-
ment parts are no longer available so the City's machine shop fabricates
its own replacement parts. The result of this and other examples is
that enterprising local agencies can maintain equipment to meet require-
ments regardless of plant or flow age.
The normal average pollutant effluent constituent concentration for
each type of process when operated at or below design flow, i.e.,
normalized flow of 1.0 or less are summarized as follows:
-------
Expected Plant Performance
Primary
Trickling Filter
Activated Sludge
(including contact
stabilization, extended
aeration, oxidation ditch)
Effluent
Concentration
mg/1
130
30
30
Suspended Solids
Effluent
Concentration
mg/1
70
30
30
For flows exceeding design flow (or normalized flow greater than
1.0) the expected constituent concentrations will increase according
to the effluent limitations manual.
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SECTION 4
BACKGROUND THEORY AND DATA SOURCES
The effluent limitations manual shows expected performance for
primary, trickling filter, activated sludge plants, and modified acti-
vated sludge processes. These process modifications include contact
stabilization, extended aeration, and oxidation ditch processes. The
oxidation ditch process may be operated as a one-pass system or as an
extended aeration process. This report reviews oxidation ditches that
are operated in the extended aeration mode.
Primary treatment is normally not affected by cold weather condi-
tions. Therefore, one curve is shown for primary plants. The basis
for the curve is suspended solids removal. This curve was developed
based on a family of curves presented by Fair & Geyer (1). The curve
was then verified by actual plant data. Removal of suspended solids
can be improved by the use of chemicals such as polymers, ferric chloride,
alum, or lime as described in the EPA manual Upgrading Existing Waste-
water Treatment Plants (2) and as practiced in the primary plants visited
in California cities with ocean discharges.
The primary plant 8005 removal performance curve was estimated
based on an assumed 50% soluble BODg fraction in the effluent. This
curve was also verified by data obtained during plant visits.
Primary plants visited to verify the performance curves are listed
in Table 1. The performance of each plant is summarized in Table 2.
Figure 1 shows the performance curve with actual annual average data
plotted on the curve.
The trickling filter 8005 effluent limitations curve was developed
by first assuming a design of a system having a raw sewage influent 8005
concentration of 200 mg/1 and a final effluent 8005 concentration of 30
mg/1. A 35% 8005 removal efficiency was assumed for primary clarifica-
tion. In order to reduce the remaining BOD5 to 30 mg/1, a 77% removal
efficiency must be attained by the trickling filter (includes final
clarification). Using the EPA Process Design Manual for Upgrading Exist-
ing Wastewater Treatment Plants (2), Figure 4-2 a hydraulic loading rate
of 0.35 gpm/sq ft was determined for a 77% removal efficiency. The de-
crease in performance for overloaded facilities was then computed by
adjusting the removal efficiencies for primary sedimentation (as developed
in this project) and trickling filters (as shown in the Process Design
Manual Figure 4-2).
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TABLE 1. PRIMARY PLANTS VISITED
1. San Elijo, CA
2. Encina, CA
3. Laguna Beach, CA
4. Durham, N. H.
5. Bangor, MA
6. Gilroy, CA
7. Aptos, CA
8. Pacific Grove, CA
9. Seaside, CA
10. Watsonvilie, CA
11. Santa Cruz, CA
12. Junction City, KS
13. Lawrence, KS
14. Wamego, KS
15. Weiser, ID
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TABLE 2.
PRIMARY PLANT DATA SUMMARY
Wastewater
Treatment
Plant
So. Tahoe P.U.D. , CA
Bangor, MA
Gilroy, CA
Laguna Beach, CA*
Encina , CA
San Elijo, CA
Aptos , CA*
Pacific Grove, CA*
Seaside, CA*
Watsonville , CA*
Santa Cruz, CA*
Weiser, ID
Lawrence, KS
Junction City, KS
Wamego , KS
Average
Average In Maximum In Ave. Removal
Pri. Effl., Pri. Effl. , In Primary,
mg/1 mg/1 Percent
BOD
90
91
-
160
143
111
-
-
-
208
209
25
181
172
266
150
SS BOD
85 145
72 152
90
100
75
67
76
59
49
74 406
118
20 60
86
228
120
88 191
SS BOD
800 36
329 36
112
-
31
32
96
64
275
153 53
29
34 36
32
42
26
266 34
SS
56
48
-
-
62
71
-
69
76
80
60
50
60
40
53
60
*Polymers used
-------
Overload
O BOD5 ANNUAL AVERAGE REMOVALS
Q SUSPENDED SOLIDS ANNUAL AVERAGE REMOVALS
Range of basin performance,
SS removal
nge of basin performance
BOD removal
0.2 0.5
1.5
2.0
2.5
3.0
4.0
Normalized Flow
Actual Flow
Design Flow
Figure 1. Estimated Removals of Suspended Solids and BOD in Primary Basins at
Various Hydraulic Loadings
-------
A specific set of criteria was chosen to develop the curve. However,
this curve would be applicable for any loadings since the performance
was calculated using a percent removal which varies linearly with varia-
tion in hydraulic loading rate. For example, a high strength waste would
require a lower hydraulic loading rate to obtain a 30 mg/1 but the same
degradation rate would apply. By using the normalized flow parameter
differences between loading rates do not change the performance result.
An exception to this rule is a situation where an actual waste loading
has changed in character from the design loading. For example, a system
may have been designed to treat domestic waste only. If a high strength
industrial waste was added to the system after it was constructed, then
the overload performance protion of the curve would not apply.
The most complete available summary on temperature effects on effluent
BOD5 concentration was developed by Gulp/We sner/Culp as part of a study
for the EPA on attached growth systems (3) . The following discussion on
temperature effects is an excerpt from that study report.
The temperature effects on effluent quality and system design requie-
ments for trickling filters are usually critical for cold weather condi-
tions. For a year-around effluent quality criteria, the cold weather
conditions will determine the size of the trickling filter because of
the lower biological reation rate. An extensive evaluation of data which
assesses temperature effects was made by Galler-Gotaas (4) . in their
formula, temperature affects on effluent quality may be stated:
"T ,20°-15
' <
Where T = temperature , celcius
6T = effluent BOD mg/1 at temperature T
LS20 = effluent BOD mg/1 at temperature 20C
For example: To obtain an effluent BOD at 30 mg/1 at a temperature of
IOC, the effluent BOD at 20C would need to be 21.2 mg/1
Eckenfelder (5) states the effect of temperature as
fT-20)
E = E x 9 where 9 = 1.035 to 1.040
T 20
In a presentation of actual data, Benzie, et al (6) provided a basis to
evaluate 9. Of the 17 plants reported, 6 plants had a 9 over 1.01 which
would exceed that predicted by Galler-Gotaas (1.011). Of these 6 plants,
5 plants employed recirculation, whereas, of the eleven plants having a
calculated 9 value below 1.01, only two plants employeed a 1:1 recirculation.
10
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A comparison of plants employing recirculation from different sources
by Gulp (7) indicates that the location of the source of recirculation
effects the results. The Webster City data and the calculated 6 value is
as follows:
Warm Weather Cold Weather
T-C E T-C E 8
Direct Filter Recirculation 18.3° 60.5 10.4 56.2 1.009
Recirculation From Final
Effluent 18.6 51.4 9.4 38.6 1.032
The effect of temperature cannot be defined conclusively with the
data collected for this report; however, temperature appears to play a
less significant role than previously believed by many investigators.
The reduced effect of temperature supports conclusions by Williamson and
McCarty (8) that the role of biological reaction rates (drastically affect-
ed by temperature) must be tempered by the limitations imposed by diffusion
of organics and oxygen through the bulk liquid and biofilm.
Operating data for trickling filters often reflect temperatures of
raw sewage. The application of the sewage to trickling filters has a
cooling effect, the extent of which is dependent upon the air temperature.
Where high recirculation rates are employed, the cooling effect will be
of greater significance on the operation of the trickling filter. There-
fore, reported temperature and plant performance data may not be readily
correlated since the trickling filter will experience cooler temperatures
than reflected by the raw sewage temperature".
First the Galler-Gotaas equation is used. Assuming a system is
designed to attain 30 mg/1 BOD5 at 20°C and the cold weather sewage tem-
perature is 5°C, then the effluent BOD5 will be 37 mg/1.
Applying the Eckenfelder equation, using the same assumptions as
above and 8 = 1.035, the effluent BOD5 will be 40 mg/1.
A comparison of these two equations shows increases in BOD^ concen-
tration of 23% and 33%. Benzie, et al (6), show decreasing BOD5 removal
efficiencies due to cold weather operation of 17 trickling filter plants
in Michigan. The loss in efficiency varied considerably depending on
recirculation practices. Averaging the data of all 17 plants, the loss
in BOD5 removal efficiency was 12%. The decrease in efficiency for those
plants employing recirculation was 21%. Those plants without recircula-
tion showed a 6% decrease in efficiency. Their analyses show the 21%
difference to be statistically significant but the 6% difference was not.
Based on the Benzie work and CWC analysis, the temperature equations
appear to be more conservative than actual operating data. However, the
operating data are monthly averages and the plants reviewed in cold
weather climates were usually designed to account for cold weather con-
ditions. Generalizations made for a study such as this one can be mis-
leading since the equations apply to specific temperatures and resulting
concentrations. The formulae do not show the effect in extreme
11
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temperature variation or effects of freezing distributor arms. Obviously,
there will not be effective treatment if the distributor is frozen. The
monthly average effluent BOD5 concentration will be raised due to the
freezing condition and the time required for the filter organisms to
recover. Conversely, a temperature drop that is brief in time may not
have the impact of a long term temperature drop.
The performance curves developed consist of two situations represent-
ing extreme conditions. Curve 1 shows the predicted performance of
plants operating under design conditions. If a plant was designed for
cold weather conditons, the resulting BOD^ effluent concentration should
be less than or equal to that predicted by the curve. In other words,
the plant designed for 5°C temperatures should meet performance curve 1
when operated at 5°C.
If a particular system is designed for an effluent concentration
greater than 30 mg/1, the curves are still valid. The user will simply
change the vertical scale. For example, if the system was designed for
40 mg/1, then 30 mg/1 should be changed to 40 mg/1 and the remaining
values increased by 10 mg/1.
There are no theoretical relationships for trickling filter loadings
and resulting suspended solids removals. The suspended solids effluent
concentration/removal efficiency curves were determined based on final
clarifier removal and adjusted by an expected soluble 8005 percentage
of 50%. This curve was then compared with actual data and adjusted
accordingly.
Both of the trickling filter curves are subject to error due to
recirculation constraints, due to design, and practices of the individual
operator. The method presented herein can account for variations in or-
ganic loading and performance using a normalized flow unless the recir-
culation was limited by the original design.
The trickling filter plants visited for performance curve verifi-
cation are listed in Table 3. Data obtained are summarized in Table 4.
Figures 2 and 3 show data plotted on the performance curves. Winter data
(December-March), summer data (June-September), and other months are
plotted separately.
BOD5 and suspended solids effluent quality performance curves shown
for conventional activated sludge (Figures 4 and 5) and extended aeration,
oxidation ditch, and contact stabilization modes of operation (Figures 6
and 7). Equal performance should be attained by any of these modes of
operation but the conventional activated sludge process showed less
reliability than the other modes of operation (see Tables 5 and 6). Based
on plant visits made in the progress of this study, the conventional
process was generally given inadequate attention by operating personnel.
The other activated sludge modifications seemed to be less subject to
variability in influent quantity and quality typically found in small
plants. They also seemed to be less affected by operator error or
12
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TABLE 3. TRICKLING FILTER PLANTS VISITED
1. Shellsburg, IA
2. Center Point, IA
3. Monticello, IA
4. Cascade, IA
5. Manchester, IA
6. Independence, IA
7. Lakeview, IA (by Kansas City, KS, EPA)
8. College Park, GA
9. Atlanta, GA
10. Cobb County, GA (three plants)
11. Athens, GA (two plants)
12. Cedartown, GA (data obtained w/o visit)
13. Newman, GA (Snake Creek plant, data
obtained w/o visit)
13
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BO
NORMALIZED FLOW-- ACTUAL FLOW
DESIGN FLOW
CURVE 1 shows performance of
plants at 20°C temperature or
plants designed for cold weather
operation.
CURVE 2 shows cold weather
(5" C) operation results for
plants designed for 20* C
operation.
(1)
See text for explanations of terms.
• SUMMER (JUNE-SEP)
• WINTER (DEC-MAR)
* OTHER MONTHS
z
O
O
o
60
5C
40
3C
20
10
QUESTIONABLE
^OPERATION
$«±±q
0.5
1.0
2.0
NORMALIZED FLOW
Figure 2. Trickling Filter Performance, BODr Effluent Concentration
14
-------
§
s
8
S
Q
I
QUESTIONABLE
OPERATION* -
TtTtttttttttffl]
GOOD OPERATION
• SUMMER (JUNE-SEP)
• WINTER (DEC-MAR)
A OTHER MONTHS
0.5
NORMALIZED FLOW
Figure 3. Trickling Filter Performance, Effluent Suspended Solids
15
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TABLE 4. TRICKLING FILTER VISITATION DATA SUMMARY
Location or
Plant Name
Iowa:
Shellsburg
Center Pt.
Monti cello
Cascade
Design
Flow
mgd
0.0825
0.200
0.800
0.220
IndependenceO. 750
Lakeview
Georgia:
Westside,
1975
Westside,
1976
Kennesaw,
1974
Sandtown ,
1976
Newman,
1975
Newman,
1976
Intr. Cr. ,
1975
Intr. Cr. ,
1976
College Pk.
1976
Athens #1,
1975
Athens #1,
1976
Athens #2,
1975
Athens #2,
1976
Cedartown,
1974
Cedartown,
1975
Cedartown,
1976
0.175
1.00
1.00
0.30
1.00
0.40
0.400
20.0
20.0
r
1.2
5.00
5.00
2.00
2.00
1.00
1.00
1.00
Actual
Flow
mgd
(annual
average)
0.0609
0.141
0.412
0.081
0.889
0.153
1.059
0.971
0.27
1.222
0.328
0.346
13.9
13.1
1.36
5.60
5.14
2.90
2.60
0.82
0.92
1.06
Normalized
Flow
(3) T (2)
0.74
0.70
0.51
0.37
1.18
0.87
1.059
0.971
1.423
1.222
0.820
0.865
0.695
0.655
1.13
1.12
1.028
1.45
1.30
0.82
0.92
1.06
Effluent
BOD5
Cone.
mg/1
47
43
39
48
85
69
25
35
24
51
30
23
40
35
43
80
64
46
47
46
17
23
BOD5 %
Removal
%*
70
72
80
76
87
69
75
72
85
70
88
88
82
83
90
69
73
73
75
77
89
88
Effl.
Susp.
Solids
Cone.
mg/1
-
-
30
38
28
50
28
29
26
31
35
64
47
58
40
40
18
22
Susp.
Solids
% Removal*
-
-
70
68
87
60
88
86
78
74
76
73
80
68
78
80
90
88
*Removal over all of plant
Note: Manchester, Iowa data not used due to sampling problems
16
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TABLE 5. BOD REMOVAL RELIABILITY
Conventional Activated
Sludge
Contact Stabilization
Extended Aeration
Percent of Time
Less Than or Equal to
30 mg/1
73
96
93
Percent of Time
Less Than or Equal to
40 mg/1
89
99
98
TABLE 6. SUSPENDED SOLIDS REMOVAL RELIABILITY
Percent of Time Percent of Time
Less Than or Equal to Less Than or Equal to
30 mg/1 40 mg/1
Conventional Activated
Sludge
Contact Stabilization
Extended Aeration
79
77
94
94
88
97
17
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inattention.
The performance curves for all of these processes were determined
by assuming that those plants visited would show better performance than
an average operation. Average data or "best-fit" lines were not used to
determine the performance curves. The objective of the plant visitations
was to show that a well-operated plant could meet the performance curves.
Actual data are plotted on Figures 4-9 to show a comparison between actual
data and the curves. These data are shown by season of the year for
demonstration of possible effluent deterioration due to cold weather.
There was no significant difference between summer and winter opera-
tion results (June, July, August, September vs December, January,
February, March). Use of a normalized flow concept, as presented in this
report, should allow for special design requirements for those plants
located in cold climates. Obviously, the extreme cold conditions will
adversely affect process performance. However, on an average monthly or
annual basis, an activated sludge process should be capable of perform-
ing according to the performance curves shown. (Assuming conservatively
designed clarifiers with adequate sludge return and wasting equipment).
Activated sludge plants that are hydraulically overloaded, but not
organically overloaded should still meet design effluent BODg levels.
Performance in terms of suspended solids will be adversely affected
unless clarifiers were designed for excessive flow variations. There-
fore, the performance curves will not directly apply to an overload
condition if the overload is due to a hydraulic overload, e.g., exces-
sive infiltration/inflow.
Conventional activated sludge, contact stabilization, and extended
aeration plant data sources are listed on Tables 7, 8, and 9 respectively.
The user manual for estimating O & M requirements contains the
assumptions used for preliminary treatment and sludge handling. The
smallest plant capacities are 0.01 mgd and the largest are 10.0 mgd.
The capacity range varies with the type of process used. There are 5
tables and 5 figures (primary plants having 4 variations) showing O & M
requirements and total O & M costs respectively. Each process is shown
for operation at design flow, 50% overload, and 100% overload (normalized
flows of 1.0, 1.5, and 2.0).
18
-------
r
•
c
§
QUESTIONABLE <
OPERATION
1C
NORMALIZED FLOW
Figure 4. Conventional Activated Sludge, BODs
NORMALIZED FLOW
• SUMMER (June - Sep)
• WINTER (Dec - Mar)
A OTHER MONTHS
d.o
Total
Summer
Winter
Annual
0
Ave.
•1.0
<60 mg/l BODS 98% 83% 99%
<50mg/l 91% 83% 83% 99%
< 40 mg/l 78% 67% 67% 75%
< 30 mg/l 64% 50% 50% 75% —
19
-------
S
i
a
LJ
g
-
^
_-
§
Figure 5.
NORMALIZED FLOW
Conventional Activated Sludge, Suspended Solids
NORMALIZED FLOW
• SUMMER (June - Sep)
• WINTER (Dec - Mar)
A OTHER MONTHS
0.0
Total |
Summer
Winter
Annual Ave.
>1 n
<60 mg/l BOD5 99%
< 55 mg/l 99%
< 50 mg/l 97% 99%
< 40 mg/l 94% 99% 93% 91%
<30 mg/l 79% 75% 79% 82%
20
60%
20%
-------
r
-
If)
s
GO
QUESTIONABLE OPERATION
NORMALIZED FLOW
• SUMMER (June - Sep)
• WINTER (Dec- Mar)
A OTHER MONTHS
Figure 6. Extended Aeration, BOD5
-------
f
8
a
M
~
_
Q
Z
L-
H-frhm
QUESTIONABLE OPERATION
10
1.0
20 3.0
NORMALIZED FLOW
• SUMMER (June -Sep)
• WINTER (Dec - Mar)
AOTHER MONTHS
Figure 7. Extended Aeration, Suspended Solids
22
-------
E
in
QUESTIONABLE OPERATION
1C
NORMALIZED FLOW
• SUMMER (June - Sep)
• WINTER (Dec- Mar)
A OTHER MONTHS
Figure 8. Contact Stabilization, BODc
23
-------
r
8
I
a
1
_
CL
QUESTIONABLE OPERATION
NORMALIZED FLOW
• SUMMER (June - Sep)
• WINTER (Dec- Mar)
A OTHER MONTHS
Figure 9. Contact Stabilization, Suspended Solids
24
-------
TABLE 7. CONVENTIONAL- ACTIVATED SLUDGE - PLANTS VISITED OR PLANTS WHOSE
MONTHLY DATA WERE OBTAINED FROM STATE ENVIRONMENTAL OFFICES
Wisconsin
1. Neillsville Sewage Treatment Plant
118 W. 5th Street
Neillsville, WI 54456
2. Sun Prairie Sewage Treatment Plant
Miller Drive
Sun Prairie, WI 53590
3. Stanley Sewage Treatment Plant
c.o City Hall
Stanley, WI 54768
4. Cross Plains Sewage Treatment Plant
1627 Cross Street
Cross Plains, WI 53528
5. Mazomanie Sewage Treatment Plant
Village Hall c/o City Clerk
Mazomanie, WI 53560
Massachusetts
6. Leominster STP
City of Leominster
Leominster, MA
New York
7. Bay Park Sewage Treatment Plant
Nassau County
240 Old Country Road
Mineola, New York 11501
Illinois
8. Elmhurst STP
625 South Route 83
Elmhurst, IL 60126
9. Homewood STP
2020 Chestnut Rd.
Homewood, IL 60430
Illinois^ (continued)
10. Barrington Plant
300 N. Raymond Ave.
Barrington, IL 60050
Oregon
11. Toledo Wastewater Treat-
ment Plant
Oregon
12. Salem Sewage Treatment
Plant
Oregon
Washington
13. GIG Harbor
Washington
25
-------
TABLE 8. CONTACT STABILIZATION PLANTS VISITED
1. City of Adams Sewage Treatment Plant
c/o City Clerk
Adams, WI 53910
2. Village of Rockdale
Sewage Treatment Plant
c/o Village Clerk Route 2
Carbridge, WI 58523
3. Colby Sewage Treatment Plant
c/o City Clerk
Colby, WI 54421
4. Wooddale North Sewage Treatment Plant
269 W. Irving Park Road
Wooddale, IL 60191
5. Village of Addison
233 S. Villa
Addison, IL
6. Carpentersville Main Treatment Plant
Lamerac Avenue
Carpentersville, IL
TABLE 9. EXTENDED AERATION PLANTS VISITED
1. Spencer Sewer Utility
117 E. Clark St.
Spencer, WI 54479
2. Russell Sewage Treatment Plant
Town of Russell
Hampden County, MA 01071
3. Westboro Sewage Treatment Plant
Westboro, MA 01581
4. Village of Richmondville
Box L
Richmondville, N.Y. 12149
5. Village of Athens
Market Street
Athens, N.Y.
6. Sedro Wooly Plant
Washington
7. Arlington
Washington
26
-------
USER INSTRUCTIONS
The influent limitations manual requires an actual average flow
and a design flow for prediction of constituent concentrations. The
abscissas show the normalized flow. The normalized flow is computed
as follows:
-. . , r, actual average flow
normalized flow =
average design flow
Example: For a plant with an average design flow of 1.5 mgd
and an actual average monthly flow of 1.7 mgd the normalized
flow is:
normalized flow = T-^T = 1-13
The normalized flow, of course, is a unitless quantity.
Once the normalized flow is determined, the curve for the appropriate
process shows the effluent constituent concentration to be expected with
questionable or good operation. Monthly or annual averages should be
used for these since day-to-day values cannot be predicted accurately
with this method.
These curves should not be used for plants that are hydraulically
overloaded but not organically overloaded. Similarly, plant data that
are influenced by a high strength waste not accounted for in the original
design would not be applicable to the performance curve prediction. If
a secondary plant is designed for an effluent constituent concentration
other than 30 mg/1, then the vertical scale should be changed by the
difference between the design value and 30 mg/1.
The performance curves are applicable to all sizes of treatment
plants.
The O & M requirements manual shows total O & M costs for each
process type as well as a tabular breakdown of the various components
of labor, power, chemical, and maintenance material costs. To determine
the operation and maintenance cost, use the figures. If a plant is
operating at design capacity or slightly below, use the "design" cost
curve. If the plant is operating at greater than design flow, determine
the percent overload and interpolate between the "design" cost curve and
"50 or 100% overloaded" cost curves.
27
-------
The cost curves for secondary processes include primary treatment
so the primary treatment cost should not be added in.
If a particular area has labor rates or power rates substantially
different from those assumed, then the tables should be used to calcu-
late the appropriate 0 & M cost.
28
-------
REFERENCES
1. Fair, G. M. and C. G. Geyer. Water Supply and Wastewater Disposal.
John Wiley & Sons, New York, 1959.
2. U. S. Environmental Protection Agency, Technology Transfer.
Upgrading Existing Wastewater Treatment Plants. October, 1971.
3. Benjes, H. H., Jr. Attached Growth Biological Wastewater Treatment,
Estimating Performance and Construction Costs and Operation and
Maintenance Requirements. Draft submitted to the U. S. Environmental
Protection Agency, Contract No. 68-03-2186. January, 1977.
4. Caller, W. S., and H. B. Gotaas. Analysis of Biological Filter
Variables. Journal of the Sanitary Engineering Division, ASCE,
90, No. 6. pp. 59-79. 1964.
5. Eckenfelder, W. W. Trickling Filter Design and Performance.
Transactions of the American Society of Civil Engineers. 128 Part
III. pp. 371-398 . 1963.
6. Benzie, W., et al. Effects of Climatic and Loading Factors on
Trickling Filter Performance. Journal Water Pollution Control
Federation. 35, No. 4. pp. 445-455. 1963.
7. Gulp, Gordon. Direct Recirculation of High Rate Trickling Filter
Effluent. JWPCF, 35, 6. p. 742. 1963.
8. Williamson, K., and P. L. McCarty. A Model of Substrate Utiliza-
tion by Bacterial Films. JWPCF, 48, No. 1. p. 9. January, 1976.
-------
PART 2
USER MANUAL FOR ESTIMATING EFFLUENT
LIMITATIONS FOR SEVERAL TYPES OF
WASTEWATER TREATMENT PROCESSES
-------
USER MANUAL FOR ESTIMATING EFFLUENT LIMITATIONS
INTRODUCTION
This manual provides a graphical means of estimating effluent limi-
tations for several types of wastewater treatment systems. Included are
primary, trickling filter, and activated sludge. These curves are de-
signed to be used where there are limited data available.
In order to accurately evaluate the effluent capability of a par-
ticular treatment plant, the plant should be visited, unit process sizes
determined, operation and maintenance practices analyzed in terms of
personnel time and skill, and condition of mechanical equipment and
structures analyzed. Generally speaking, there is not enough time or
manpower to accomplish this task. Usually, the only data available are
from periodic NPDES permit reports and from EPA 7500-5 forms. Data
from these sources include actual flow quantities, effluent 6005 and sus-
pended solids concentrations, removal efficiencies, design flow, opera-
tion and maintenance budgets and personnel inventories and skill levels.
The following user manual requires data on design flow, actual flow
(average), and effluent suspended solids and 6005 concentrations.
Each of the following curves shows an effluent constituent concen-
tration related to a normalized flow or a percent removal related to
normalized flow. Normalized flow is the actual flow divided by the design
flow.
Primary Plants
Estimated removals of suspended solids and BOD5 are shown on Figure
1. The design loading was assumed to be 800 gpd/sq ft. The suspended
solids curve envelope was developed based on information by Fair & Geyer*.
Data points from individual plants that are above the curve are indicative
of good operation, use of chemical aids, or some other specialized means
of improving performance. The BOD,- removal curve was derived based on an
assumed 50% insoluble BOD5 fraction which would be removed as suspended
solids. These curves are applicable to conventional primary sedimentation
plants.
*Fair, G.M. & Geyer, J.C., Water Supply S Waste Water Disposal,
John Wiley & Sons, 1954
-------
100
90
Overload
Range of basin performance,
SS removal
nge of basin performance,
BOO removal
0.2 0.5
1.0
1.5
2.0
2.5
3.0
4.0
Normalized Flow
Actual Flow
Design Flow
Figure 1. Estimated Removals of Suspended Solids and BOD in Primary
Basins at Various Hydraulic Loadings
-------
Trickling Filter Plants
Expected BOD,- and suspended solids concentrations for trickling
filter plants are shown on Figures 2 and 3, respectively. Suspended
solids removal efficiency is more dependant on clarifier loading. There-
fore, the suspended solids curve is a function of clarifier hydraulic
loading. The design loading is assumed to be 800 gpd/sq ft. Data were
obtained from a published report by Benzie, et al**, on Michigan plants,
operating data from five Iowa plants, operating and field test data from
the EPA Kansas City, Kansas, Office of Surveillance, and Analysis, and
eight Georgia plants. Selection of these geographical locations enabled
review of cold weather effects on treatment efficiency.
Curve 1 on Figure 2 shows the expected 6005 effluent concentration
for those plants that are operating under the same conditions as were
assumed by the designer. In other words, if a plant was designed for
cold weather operation, then cold weather should not cause a deteriation
in performance. Curve 2 on Figure 2 shows the expected performance of
plants operating at 5°C influent temperatures that were designed for 20°C
influent temperature. The performance curves obviously cannot account
for situations where filter distributors freeze.
Activated Sludge Plants
Activated sludge plants include conventional, extended aeration
(oxidation ditch considered as an extended aeration process) and contact
stabilization. Effluent concentrations for BOD5 and suspended solids for
the conventional plants are shown on Figures 4 and 5 respectively. BOD5
and suspended solids effluent concentrations for the other process modifi-
cations are shown on Figures 6 and 7. A comparison of these figures shows
that the overload conditions impact the conventional plants but not the
modified activated sludge processes. The BODs effluent concentration
values for overloaded plants were determined by the Eckenfelder equation
as described in the first section of this manual. Theoretically, the
modified process should behave similarly, but the field data showed that
these processes still produced design effluent concentrations even at
flows twice the design flow. Therefore, the extended aeration, oxidation
ditch, and contact stabilization plants are shown with 30 mg/1 effluent
concentrations up to normalized flows of 2.0.
The suspended solids results were estimated based on performance of
those plants visited. The performance curve was drawn to include the
data from those plants that were judged to be well-operated facilities.
This curve is not an average of the data collected nor is it a "best fit"
line.
**Benzie, et al, "Effects of Climatic and Loading Factors on Trickling
Filter Performance", JWPCF, April, 1963, Vol. 35, No. 4, pp. 445-455.
-------
:
NORMALIZED Fl OW ACTUAL FLOW
DESIGN FLOW
CURVE 1 shows performance of
plants at 20°C temperature or
plants designed (or cold weather
operation.
CURVE 2 shows cold weather
(5* C) operation results for
plants designed for 20" C
operation.
(1)
See text for explanations of terms.
r
f
|
~
CJ
in
BC
st
:
0.5
1.0
2.0
NORMALIZED FLOW
Figure 2. Trickling Filter Performance, BODc Effluent Concentration
-------
BO
o
1U
u
§
o
M
g
_'
s
Q
UJ
II
50
40
3C
20
QUESTIONABLE
OPERATION --4-
0.5
1.0
2.0
NORMALIZED FLOW
Figure 3. Trickling Filter Performance, Effluent Suspended Solids
-------
o
o
u~
g
QUESTIONABLE
I! OPERATION
NORMALIZED FLOW
Figure 4. Conventional Activated Sludge, Effluent BOD,-
-------
I
z
g
H
<
UJ
o
o
o
M
9
s
c
UJ
o
LU
a
QUESTIONABLE
; OPERATION;;
NORMALIZED FLOW
Figure 5. Conventional Activated Sludge, Effluent Suspended Solids
-------
M
! o
I
I
5
G
-
1
H
M
20
10
t •-
...
• •
....
—
-
-
•
QUESTIONABLE OPERATION
GOOD OPERATION
0.5
1.0
2.0
NORMALIZED FLOW
Figure 6. Extended Aeration, Oxidation Ditch, or Contact Stabilization Performance
Effluent BOD,
-------
9
Li.
CJ-
o
in
c.
Ill
70
63
50
30
20
10
...
....
...
••
....
..:
...
....
-
- ----- (-H-i-t
-
-QUESTIONAB E OPERATION
•Hf- tH
4-44+444
&
QGOOD OPERATION^
.
::
....
T
.-.,
0.5
1.0
2.0
NORMALIZED FLOW
Figure 7. Extended Aeration, Oxidation Ditch, or Contact Stabilization Performance
Effluent Suspended Solids
-------
PART 3
USER MANUAL FOR ESTIMATING
OPERATION AND MAINTENANCE REQUIREMENTS
-------
USER MANUAL
FOR
ESTIMATING OPERATION AND MAINTENANCE REQUIREMENTS
INTRODUCTION
This manual provides information and methods for estimating opera-
tion and maintenance requirements and costs for publicly owned primary
and secondary wastewater treatment plants. It is aimed specifically
at plants which are not scheduled to receive federal construction grants
in the near future. Most plants in this category are in the capacity
range of .01 to 10.0 mgd. The operation and maintenance requirements
are estimated at a level which should allow such plants to achieve
optimum performance with the facilities available.
These operation and maintenance requirements are based, to the
extent possible, on experiences at actual operating facilities. Such
requirements will vary between similar facilities depending upon the
exact unit processes within that facility. The facilities and unit
processes upon which these stated requirements are based are outlined
hereinafter. More complex unit processes than those assumed may require
additional operation and maintenance requirements and less complex unit
processes somewhat lesser operation and maintenance. The assumptions
made herein should result in information applicable to the average plant
of the particular type of facility.
Operation and maintenance costs were also determined for overloaded
treatment facilities.
USE OF MANUAL
The manual is designed to provide guideline operation and mainten-
ance requirements for various types of treatment processes. The require-
ments can be determined by personnel having only a limited amount of
information from the facility. The guideline requirements determined
from this manual can then be used to evaluate the level of operation
and maintenance at the particular facility. The actual operation and
maintenance requirements will vary widely from facility to facility,
but the requirements in this manual should be adequate for satisfactory
operation of the specific types facilities. The requirements in the
tables for facilities operating at design capacity are broken down into
several categories for cases where more detail is needed while the figures
indicate total requirements.
-------
TREATMENT PROCESSES
Plants are classified according to treatment processes and design
flow capacity for estimating purposes.
The facility classifications and design flow ranges are outlined
hereafter.
FACILITY FLOW RANGE, MGD
Primary Plant 0.5 to 10
Trickling Filter Plant 0.5 to 10
Contact Stabilization Plant 0.1 to 1.0
Extended Aeration Package Plant 0.01 to 0.1
Oxidation Ditch Plant 0.05 to 5.0
Conventional Activated Sludge Plant 1.0 to 10
Primary Plant
The assumed basic primary plant consists of headworks typical for
the flow, raw sewage pumping, primary sedimentation, chlorination, anaero-
bic digestion, outdoor sand drying beds and laboratory. Information is
provided for analysis of primary plants with vacuum filtration for sludge
dewatering (rather than sludge drying beds) and for primary plants with
chemical addition to aid the sedimentation process.
Trickling Filter Plant
The assumed trickling filter plant consists of headworks, raw sewage
pumping, primary sedimentation, trickling filtration, (rock media), re-
circulation, final clarification, chlorination, anaerobic digestion, out-
door sand drying beds, and laboratory.
The operation and maintenance information applies to both covered
and open trickling filters.
Contact Stabilization Plant
Contact stabilization plants include complete package type including
tankage or those designed for installation into on-site tankage as appro-
priate to the size. Contact stabilization plants include raw sewage
pumping, comminutor, contact zone, settling zone, reaeration zone,
chlorination, aerobic digestion, outdoor sand drying beds, and laboratory.
Extended Aeration Package Plant
The assumed plant is a standard package plant as supplied by a number
of manufacturers. Tankage is typically steel or fiberglass. The plants
include raw sewage pumping, comminutor, aeration, final clarification,
sludge return and wasting, sludge storage, blowers and blower housing,
chlorination, and a small laboratory space.
-------
Oxidation Ditch Plant
The assumed plant includes headworks, raw sewage pumping, oxidation
ditch, final clarification, sludge return and wasting, outdoor sludge
drying beds, chlorination, and laboratory facilities. The operation and
maintenance requirements are based on information from 20 operating plants.
These plants are operated in the extended aeration mode.
Conventional Activated Sludge Plant
The assumed plant consists of headworks, raw sewage pumping, primary
sedimentation, aeration, secondary clarification, chlorination, sludge
return and wasting, anaerobic digestion, vacuum filtration, and labora-
tory. Operation and maintenance requirements were developed by unit
process from published information and experiences of actual operating
plants.
OPERATION AND MAINTENANCE REQUIREMENTS
Operation and maintenance requirements were determined, to the extent
possible, from experiences of actual operating facilities of similar type
and complexity. This field information was augmented and cross checked
by calculations, information from published literature, and other sources
of O & M information. The information should be typical for average
facilities of the specified type.
Operation and maintenance information is developed in four categories;
labor (operation and maintenance), energy, chemicals, and maintenance
materials.
Labor
Labor requirements include all operation, maintenance, administration,
sampling, and laboratory work required for-the facility. Sampling and
laboratory requirements vary depending on local regulatory agency permit
programs. Generally speaking, 5-15 man-hours per week are devoted to
sampling and laboratory analysis for plants less than 3 mgd. For 3-10
mgd capacities, this workload increases to 30-40 man-hours per week. The
lower values apply to primary and trickling filter plants. The higher
values apply to activated sludge plants. Labor rates vary widely and are
generally lower for small plants; however, a uniform rate of $9.00 per
hour is used herein. This rate includes the cost of all fringe benefits
and training.
Energy
The energy requirements are all converted to equivalent electrical
units and include lighting, heating, controls, and electric drives. A
unit cost of $0.03 per kwh is assumed.
-------
Chemicals
Chemical requirements include chlorine, chemicals required for
sludge conditioning, and chemicals for other uses in the plant. Chemi-
cal unit prices are based on recent quotations related to type and
quantity.
Maintenance Materials
Maintenance materials include all parts and supplies used in the
normal operation and maintenance of the facility. These requirements
are based on recent experiences of operating facilities and vary widely.
Presentation
The operation and maintenance information is presented in tabular
and graphical form for easy use as follows. The tabular information is
broken down by O & M category and the graphical information shows total
requirements.
TYPE FACILITY TABLE NO. FIGURE NO.
Primary 1 l
Trickling Filter 2 2
Contact Stabilization 3 3
Extended Aeration Package 4 4
Oxidation Ditch 5 5
Conventional Activated Sludge 6 6
-------
1,000
M
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9
8
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3456789 2 3 45678 9
m 1.0
PLANT CAPACITY, mgd
Figure Ib. Total Annual Operation and Maintenance Cost
Primary Plants Chemical Addition and Drying Beds
February 1977
-------
jr
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c
.-
O
u
1,000
9
8
7
6
5
100
7
6
5
4
10
0.1
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50% OVERLOAD
DESIGN
3 456789
3 456789
1.0
IG
PLANT CAPACITY, mgd
Figure Ic. Total Annual Operation and Maintenance Cost
Primary Plants With Vacuum Filtration
February 1977
-------
D
s
u
_
i
1,000
9
8
7
6
5
100
7
6
5
4
10
0.1
100% OVERLOAD
50% OVERLOAD
DESIGN
X
X
X
3 456789
3 4 5 6 7 89
1.0
10
PLANT CAPACITY, mgd
Figure Id. Total Annual Operation and Maintenance Cost
Primary Plants With Chemical Addition and Vacuum Filtration
February 1977
-------
M
5
D
*
5
O
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3
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21
<
1,000
9
8
7
6
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100
7
6
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4
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100% OVERLOAD
. 50% OVERLOAD
—'DESIGN
3 456789
3 4 5 6 7 89
1.0
1C
PLANT CAPACITY, mgd
Figure 2. Total Annual Operation and Maintenance Cost
Trickling Filter Plants
February 1977
-------
9
8
7
6
5
4
3
J 2
o
-o
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c
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3 456789
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1.0
3 456789
10
PLANT CAPACITY, mgd
Figure 3. Total Annual Operation and Maintenance Cost
Contact Stabilization Plants
February 1977
-------
100
M
c
D
I/I
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9
8
7
6
5
4
3
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3 456789
0.1
3 4 5 6 7 89
1.0
PLANT CAPACITY, mgd
Figure 4. Total Annual Operation and Maintenance Cost
Package Extended Aeration Plants
February 1977
-------
:
10,000
9
B
7
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-
4
3
1,000
9
:
1
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3456789 2 3456789 2 3456789
.01 0.1 1.0 1
PLANT CAPACITY, mgd
Figure 5. Total Annual Operation and Maintenance Cost
Oxidation Ditch Plants
February 1977
-------
1,000
9
B
1
5
-
—
:
.
E
-
I/I
-:
L
100
9
6
7
!
A
3
10
0.1
100% OVERLOAD
50%
DESIGN
3456789
1.0
345678 9
10
PLANT CAPACITY, mgd
Figure 6. Total Annual Operation and Maintenance Cost
Conventional Activated Sludge
February 1977
-------
TABLE 1. PRIMARY PLANTS - ANNUAL OPERATION AND
MAINTENANCE REQUIREMENTS, 1976
LABOR
ENERGY
Hours
3,800
4,700
8,000
11,000
20,000
$1000 '*'
34.2
42.3
72.0
99.0
180.0
Plant Capacity, MGD
WITH DRYING BEDS
0.5
1.0
3.0
5.0
10.0
WITH CHEMICAL ADDITION AND DRYING BEDS
0.5 4,100 36.9
1.0 5,200 46.8
3.0 9,000 81.0
5.0 12,000 108.0
10.0 21,000 189.0
WITH VACUUM FILTRATION
0.5 5,580 50.2
1.0 6,670 60.0
3.0 11,540 103.9
5.0 15,050 135.5
10.0 22,350 201.2
WITH CHEMICAL ADDITION AND VACUUM FILTRATION
0.5 6,020 54.2
1.0 7,160 64.4
3.0 12,170 109.5
5.0 15,730 141.6
10.0 23,180 208.6
1000 KWH
104.3
142.4
228.5
311.0
481.6
108.2
146.5
233.1
315.8
486.7
8.7
17.4
26.1
34.8
43.5
12.6
21.5
30.7
39.6
48.6
$1000**'
3.1
4.3
6.9
9.3
14.4
3.2
4.4
7.0
9.5
14.6
0.3
0.5
0.8
1.0
1.3
0.4
0.6
0.9
1.2
1.5
Maint.
Mat. ,
$1000
7.4
10.6
17.9
24.7
38.0
7.7
10.9
18.2
25.0
38.4
0.2
0.5
1.2
2.0
3.7
0.5
0.8
1.5
2.3
4.1
Chemicals,
$1000
3.0
5.0
10.0
18.0
33.0
5.8
10.7
24.9
40.8
78.6
3.6
6.0
12.5
22.0
41.0
6.4
11.7
27.4
44.8
86.6
Total L $1000
Normal
Load
47.7
62.2
106.8
151.0
265.4
53.6
72.8
131.1
183.3
320.6
54.3
67.0
118.4
160.5
247.2
61.5
77.5
139.3
189.9
300.8
50%
Overload —
59.5
81.7
149.8
213.6
373.3
65.4
92.3
174.1
245.9
428.5
66.1
86.5
161.4
223.1
355.1
73.3
97.0
182.3
252.5
408.7
100%
Overload —
67.6
94.1
176.4
251.0
434.8
73.5
104.7
200.7
283.3
490.0
74.2
98.9
188.0
260.5
416.6
81.4
109.4
208.9
289.9
470.2
(*) At $9.00 Per Hour
(+) At $0.03 Per KWH
(+) Costs for overloaded plant include extra raw sewage pumping, solids handling, and chemicals.
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TABLE 2. TRICKLING FILTER PLANT - ANNUAL OPERATION
MAINTENANCE REQUIREMENTS, 1976
LABOR
Plant Capacity, MGD
0.5
1.0
3.0
5.0
10.0
Hours
3,900
5,000
8,700
12,000
20,000
$1000(*'
35.1
45.0
78.3
108.0
180.0
ENERGY
1000 KWH
158.3
222.4
402.5
573.0
915.6
$1000(+)
4.7
6.7
12.1
17.2
27.5
Maint.
Mat. ,
$1000
8.9
12.7
22.0
30.3
47.3
Chemicals,
$1000
3.0
5.0
10.0
18.0
33.0
Total, $1000
Normal
Load
51.7
69.4
122.4
173.5
287.8
50%
Overload —
64.4
90.4
169.2
242.6
405.2
100%
Overload -
72.8
103.3
196.8
351.0
470.4
(*) At $9.00 Per Hour
(+) At $0.03 Per KWH
(^) Costs for overloaded plant include extra raw sewage and recirculation pumping, solids handling, and chemicals.
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TABLE 3. CONTACT STABILIZATION PLANTS - ANNUAL OPERATION AND
MAINTENANCE REQUIREMENTS, 1976
LABOR
Plant Capacity, MGD
0.10
0.25
0.50
0.75
1.00
Hours
1,800
2,600
3,900
5,000
6,000
siooo'**
16.2
23.4
35.1
45.0
54.0
ENERGY
1000 KWH
80
190
380
600
800
$1000<*>
2.4
5.7
11.4
18.0
24.0
Maint.
Mat.,
$1000
4.0
6.0
7.5
9.0
10.6
Chemicals,
$1000
0.7
1.5
2.2
4.0
5.3
Normal
Load
23.3
36.6
56.2
76.0
169.9
Total, $1000
50%
Overload —
29.0
48.3
76.4
103.7
204.4
(+)
Overload —
32.4
54.2
87.5
117.6
222.5
(•) At $9.00 Per Hour
(+) At $0.03 Per KWH
(+) Costs for overloaded plant include extra raw sewage pumping and aeration energy, solids handling and chemicals.
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TABLE 4. PACKAGE EXTENDED AERATION PLANTS - ANNUAL OPERATION
MAINTENANCE REQUIREMENTS, 1976
LABOR
Plant Capacity, HGD
0.01
0.02
0.05
0.07
0.09
Hours
500
650
1,000
1,200
1,400
SIOOO'*'
4.5
5.8
9.0
10.8
12.6
ENERGY
1000 KWH
13
20
40
70
90
$1000(+)
0.4
0.6
1.2
2.1
2.7
Maint.
Mat.,
$1000
0.9
1.2
2.7
3.1
3.5
Chemicals,
$1000
0.1
0.2
0.4
0.5
0.6
Normal
Load
5.9
7.8
13.3
16.5
19.4
Total, $1000
Overload —
7.0
9.5
16.7
20.8
24.7
100* .+.
Overload —
7.6
10.7
18.8
23.5
27.9
(*) At $9.00 Per Hour
(+) At $0.03 Per KWH
(+) Costs for overloaded plant include extra raw sewage pumping and aeration energy, solids handling and chemicals.
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TABLE 5. OXIDATION DITCH PfANT - ANNUAL OPERATION
MAINTENANCE REQUIREMENTS, 1976
LABOR
Plant Capacity, MGD
0.05
0.10
0.50
1.00
3.00
5.00
10.00
Hours
1,756
2,000
3,044
4,156
9,200
15,200
30,400
$1000 '*'
15.8
18.0
27.4
37.4
82.8
136.8
273.6
ENERGY
1000 KWH
46
72
280
500
1,200
2,000
3,200
$1000'*'
1.4
2.2
8.4
15.0
36.0
60.0
96.0
Ma int.
Mat.,
$1000
0.7
1.0
2.7
4.2
10.0
17.5
30.0
Chemicals,
$1000
0.5
0.7
2.2
4.7
13.0
25.0
50.0
Total, $1000
Normal
Load
18.4
21.9
40.7
61.3
141.8
239.3
449.6
50%
Overload —
21.8
27.6
60.9
95.8
223.8
362.9
665.5
Overload —
23.9
31.0
72.0
113.9
265.4
423.3
769.0
(*) At $9.00 Per Hour
(+) At $0.03 Per KWH
{+) Costs for overloaded plant include extra raw sewage pumping and aeration energy, solids handling and chemicals.
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TABLE 6. CONVENTIONAL ACTIVATED SLUDGE - ANNUAL OPERATION
MAINTENANCE REQUIREMENTS, 1976
LABOR
Plant
0.
1.
3.
5.
10.
Capacity , MOD
5
0
0
0
0
Hours
4,300
5,498
10,000
15,000
25,000
$1000
38.
49.
90.
135.
225.
(*)
7
5
0
Q
0
ENERGY
1000 KWH
433
548
1,200
1,875
3,653
$1000
13.
16.
36.
56.
109.
(+)
0
4
0
2
6
Maint.
Mat.,
$1000
9.
11.
18.
24.
36.
0
7
0
7
1
Total, $1000
Chemicals,
$1000
2.0
4.0
11,0
20.0
45.0
Normal
Load
62,7
81.6
155.0
235.9
415.7
50% (+)
Overload —
82.
116.
237.
358.
631.
9
1
0
5
6
100%
Overload -
114.0
134.2
278.6
419.9
751.1
(*) At $9.00 Per Hour
(+) At $0.03 Per KWH
(+) Costs for overloaded plant include extra raw sewage pumping and aeration energy, solids handling and chemicals.
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