United States Office of Reprint of USA
Environmental Protection Water Program Operations (WH-547) CRREL, SR 79-7
Agency Washington DC 20460 April 1979
- 60 , ,;
Water
vEPA Energy Requirements
for Small Flow
Wastewater Treatment
Systems
MCD-60
-------
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that the contents necessarily reflect the views and policies of the
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-------
Energy Requirements
for Small Flow
Wastewater Treatment
Systems
E.J. Middlebrooks and C.H. Middlebrooks
MCD-60
Reprinted by
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF WATER PROGRAM OPERATIONS
MUNICIPAL CONSTRUCTION DIVISION
WASHINGTON, D.C. 20460
-------
EPA Comment
This report was reprinted by EPA's Office of Water Program Operations
as one of a series of reports that contain information on topics of
major interest related to municipal wastewater treatment and sludge
management. Reports in this series provide detailed information on the
planning, design, and operation of municipal wastewater treatment systems.
Energy is a major concern to EPA as well as to the Nation. This
report summarizes energy requirements for small flow wastewater treatment
systems and presents energy data for various wastewater treatment system
components. Energy requirements for wastewater systems that contain
those components can be estimated using data presented in this report.
The reports in this series do not contain either EPA policy or EPA
regulatory requirements. They are reprinted to assist consulting engineers,
state and local regulatory personnel, and EPA Regional Administrators
during preparation, review, and evaluation of projects proposed for
funding through EPA's Construction. Grants Program.
Harold P. Cahill, Jr., Director
Municipal Construction Division
Office of Water Program Operations
-------
Special Report 79-7
April 1979
ENERGY REQUIREMENTS FOR SMALL FLOW
WASTEWATER TREATMENT SYSTEMS
E.J. Middlebrooks and C.H. Middlebrooks
Prepared for
DIRECTORATE OF MILITARY PROGRAMS
OFFICE, CHIEF OF ENGINEERS
By
UNITED STATES ARMY
CORPS OF ENGINEERS
COLD REGIONS RESEARCH AND ENGINEERING LABORAIORY
HANOVER, NEW HAMPSHIRE, USA
-------
PREFACE
This report was prepared by E. Joe Middlebrooks and Charlotte H.
Middlebrooks, both of Middlebrooks and Associates, Logan Utah.
The study was performed for the U.S. Army Cold Regions Research
and Engineering Laboratory (USA CRREL) and was funded under DA Project
4A762720A896, Environmental Quality for Construction and Operation of
Military Facilities; Task 02, Pollution Abatement Systems; Work Unit 004,
Wastewater Treatment Techniques in Cold Regions.
The final scope of study was defined by Sherwood C. Reed of CRREL.
He served as technical monitor during the course of the study and his
efforts in this regard contributed significantly to the successful com-
pletion of this report.
Technical review of this report was performed by Sherwood C. Reed,
Robert S. Sletten, C. James Martel, and Edward F. Lobacz of CRREL.
Permission to reproduce drawings, tables, promotional and instruc-
tional materials by the following firms is greatly appreciated.
Journal Water Pollution Control Federation, Washington, B.C.
Public Works Journal Corporation, Ridgewood, New Jersey
Ann Arbor Science Publishers, Inc., Ann Arbor, Michigan
Water and Sewage Works, Scranton Gillette Communications, Inc.,
Chicago, Illinois
The assistance of Ms. Barbara South in the preparation of this
manuscript is greatly appreciated. Ms. Mona McDonald's editorial
review was also most helpful.
The contents of this report are not to be used for advertising or
promotional purposes. Citation of brand names does not constitute an
official endorsement or approval of the use of such commercial products.
111
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TABLE OF CONTENTS
Page
INTRODUCTION 1
General 1
Other Studies 1
METHODS AND PROCEDURES 9
Equation Development . 9
Design Parameters 9
Wastewater Characteristics 9
Energy Recovery 10
Secondary Energy 10
RESULTS AND DISCUSSION 11
Energy Equations 11
Treatment Systems 11
Energy Consumption 11
Carbon and Ion Exchange Regeneration 37
Gas Utilization 37
Effluent Quality and Energy Requirements 37
Conventional Versus Land Treatment 39
CONCLUSIONS 45
APPENDIX A: EQUATIONS DESCRIBING ENERGY REQUIREMENTS .... 47
APPENDIX B: RAW WASTEWATER CHARACTERISTICS 77
APPENDIX C: SLUDGE CHARACTERISTICS 79
LITERATURE CITED 81
xv
-------
LIST OF FIGURES
Figure Page
1 Energy requirements for 30 mgd secondary treatment
plants (Wesner and Burris, 1978) 3
2 Trickling filter treatment with anaerobic digestion
(BOD5 = 5-day, 20°C biochemical oxygen demand; SS =
suspended solids) 12
3 Rotating biological contactor treatment with anaerobic
digestion 13
4 Activated sludge treatment with anaerobic digestion ... 14
5 Activated sludge treatment with sludge incineration ... 15
6 Physical-chemical advanced secondary treatment 16
7 Extended aeration with intermittent sand filter .... 17
8 Slow rate irrigation 18
9 Rapid infiltration 19
10 Overland flow 20
11 Facultative lagoon-intermittent sand filter
treatment 21
12 Advanced wastewater treatment 22
13 Comparison of energy requirements for trickling filter
effluent treated for nitrogen removal and filtered
versus facultative pond effluent followed by overland
flow treatment 40
14 Comparison of energy requirements for activated sludge,
nitrification, filtration and disinfection versus
facultative pond effluent followed by rapid infil-
tration and primary treatment followed by rapid
infiltration 41
15 Comparison of energy requirements for secondary
treatment followed by advanced treatment versus
facultative pond effluent followed by slow rate land
treatment 43
v
-------
LIST OF TABLES
Table Page
1 Energy requirements, 7.5 mgd, Lake Tahoe Wastewater
Treatment system (Gulp and Gulp, 1971; Gulp, 1978) ... 2
2 Examples of systems to be considered in evaluating
energy implications of wastewater reuse (Hagan and
Roberts, 1976) 5
3 Estimated energy (electricity and fuel) for alter-
native treatment processes (Benjes, 1978) 6
4 Estimated total annual and unit costs for alternative
treatment processes with a design flow of 1.0 mgd
(Tchobanoglous, 1974) 7
5 Energy comparison of sludge dewatering equipment
(Jacobs, 1977) 8
6 Energy comparison of biological treatment systems
(Jacobs, 1977) 8
7 Guidance for assessing level of preapplication for land
treatment (EPA, 1978) 23
8 Energy requirements for components of trickling filter
system with anaerobic digestion in the intermountain
area of the USA 24
9 Energy requirements for components of a rotating
biological contactor treatment system with anaerobic
digestion located in the intermountain area of the
USA 25
10 Energy requirements for components of activated sludge
system with anaerobic digestion in the intermountain
area of the USA 26
11 Energy requirements for components of activated sludge
system with sludge incineration in the intermountain
area of the USA 27
12 Energy requirements for components of a physical-
chemical advanced secondary wastewater treatment
system located in the intermountain area of the
USA 28
-------
LIST OF TABLES (CONTINUED)
Table Page
13 Energy requirements for components of an extended
aeration system with slow sand filter located in the
intermountain area of the USA ......... 29
14 Energy requirements for components of slow rate
(irrigation) land treatment system located in the
intermountain area of the USA 30
15 Energy requirements for components of a primary
wastewater treatment plant followed by rapid infil-
tration land treatment systems located in the
intermountain area of the USA 31
16 Energy requirements for components of rapid infil-
tration land treatment systems located in the
intermountain of the USA 32
17 Energy requirements for components of overland flow
land treatment systems located in the intermountain
area of the USA 33
18 Energy requirements for components of a facultative
lagoon-intermittent sand filter system located in the
intermountain area of the USA 34
19 Energy requirements for components of an advanced
wastewater treatment system processing secondary
effluent located in the intermountain area of the
USA 35
20 Energy requirements for components frequently appended
to secondary wastewater treatment plants 36
21 Expected effluent quality and total energy requirements
for various sizes and types of wastewater treatment
plants located in the intermountain area of the USA . . 38
22 Total annual energy for typical 1 mgd system
(electrical plus fuel, expressed as 1000 kwh/yr) ... 42
vii
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CONVERSION FACTORS: U.S. CUSTOMARY TO
METRIC (SI) UNITS OF MEASUREMENT
These conversion factors include all the significant digits given
in the conversion tables in the ASTM Metric Practice Guide (E 380), which
has been approved for use by the Department of Defense. Converted values
should be rounded to have the same precision as the original (see E 380).
Multiply
inch
inch
foot
yard^
foot 3
yard^
gallon
pound
pound/inch^
pound/foot^
kilowatt-hour
horsepowei—hour
watt
watt
Btu
BTu
standard feet^ of
air/minute
By
25.4*
2.54
0.3048*
0.8361274
0.02831685
0.764549
0.003785412
453.6
6894.757
16.01846
3.600 x 106
2.6845 x 106
1.000
0.0013410
1054.85
0.000293
0.47195
To Obtain
millimeter
cent imeter
meter
meter2
meter3
meter^
meter^
gram
pascal
kilogram/meter-^
joule
joule
joule/second
horsepower
joule
kilowatt-hour
standard meter^ of
air/minute
Exact
viii
-------
SUMMARY
With increasing energy costs, energy consumption is assuming a
greater proportion of the annual cost of operating wastewater treatment
facilities of all sites, and because of this trend, it is likely that
energy costs will become the predominant factor in the selection of cost-
effective small-flow wastewater treatment systems.
Where suitable land and groundwater conditions exist, a facultative
pond followed by rapid infiltration is the most energy-efficient system
described in this report. Where surface discharge is necessary and
impermeable soils exist, a facultative pond followed by overland flow
is the third most energy-efficient system described. Facultative ponds,
followed by slow or intermittent sand filters, are the fourth most energy-
efficient systems discussed, and are not limited by local soil or ground-
water conditions.
IX
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INTRODUCTION
General
The concern for energy use at wastewater treatment facilities has
developed well after many of the plans were made for the management
of water pollution in the United States. This is true in military as
well as in civilian installations. With changing standards and technology,
information on energy requirements for small (0.05 to 5 mgd) wastewater
treatment systems is needed to avoid future errors and to provide infor-
mation to assist in designing and planning. Several estimates have been
made for large systems, usually in the range of 5 to 100 mgd, but because
hundreds of small systems are being used by military installations, it is
imperative that information be gathered on energy requirements for waste-
water treatment for small systems.
This report summarizes the energy requirements for all viable alter-
natives presently available to military installations for the treatment of
small flow rates (0.05 - 5 mgd) of wastewater. It compares various
treatment combinations, and presents in tabular form the energy require-
ments for the most viable alternatives. The data can be combined to
produce an estimate of the energy requirements for all currently available
unit operations and processes.
Other Studies
Only one comprehensive study of the energy requirements associated
with wastewater treatment has been performed. Wesner et al. (1978)
presented a detailed analysis of energy requirements by unit operations
and unit processes employed in wastewater treatment. The results of this
study were presented in graphical form with accompanying tables out-
lining the design considerations employed in developing the graphs.
Energy requirements were presented in terms of the design flow rate
of the treatment system in most cases, but when a wide choice of load-
ing rates was applicable, the graphs were presented in terms of surface
area or the flow rate applied to the component of the system. Portions
of the Wesner et al. (1978) results are presented in detail in Appendix
A in this report
Gulp (1978) has presented an analysis of alternatives for future
wastewater treatment at South Tahoe, California. This illustrates the
increasing sensitivity of energy costs. When the original advanced waste-
water treatment system was constructed in the late 1960's, energy was not
costly and was not usually a significant factor in concept selection and
design. Table 1 illustrates the energy required for alternatives com-
pared with the original design. It is anticipated that the final product
-------
Table 1. Energy requirements 7.5 mgd, Lake Tahoe Wastewater Treatment
system (Gulp and Gulp, 1971; Gulp, 1978).
Total energy3
(electricity and fuel
Alternative expressed as
equivalent 1000
kwh/yr)
Original system complete secondary treatment,
AWT system, effluent export to Indian Creek 64,500
Reservoir
1978 Alternatives
Continue secondary, nitrification, effluent 39,400
export to Indian Creek Reservoir
Continue secondary, nitrogen removal (ion ,_ -44
exchange) effluent export to I.C.R. '
Continue secondary on site, flood irri- _,. -,.»
gation land treatment in Carson River Basin '
Does not include secondary energy requirements for chemical
manufacture.
from the flood irrigation land treatment alternative will be at least
equal in quality to the original design effluent.
Energy requirements for four wastewater treatment systems, includ-
ing sludge processing, that are capable of achieving secondary effluent
quality and complete sludge treatment and disposal were presented by
Wesner and Burris (1978). Estimated energy requirements were presented
for 1) trickling filter with anaerobic digestion, 2) activated sludge with
anaerobic digestion, 3) activated sludge with sludge incineration, and 4)
independent physical-chemical treatment with sludge incineration using 5
and 30 mgd capacities. A comparison of energy requirements for the four
systems treating 30 mgd is shown in Figure 1. The potential for solar
energy as a method of heating the digester and control building was
discussed. Heat recovery from sewage effluents using heat pumps to heat
digesters and buildings was considered.
Zarnett (1976, 1977, and undated) has examined the energy require-
ments for water and wastewater treatment plants and has presented the
requirements by unit operations employed. The results were presented
by unit operation to make it convenient to assess any treatment system
on the basis of total energy consumption. By combining various flow
configurations, a system capable of producing a given effluent quality
can be assembled and the energy requirements compared. Zarnett cautions
-------
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that the data were presented for comparative purposes and should not be
used as absolute values.
Energy requirements for various types of wastewater treatment
plants were presented by Hagan and Roberts (1976). In addition to the
discussion of conventional secondary and tertiary treatment systems,
land treatment systems were considered. Tradeoffs between pollutants
removed from wastewater and pollutants added to the environment by
energy use were discussed. It was pointed out that decreasing returns
are obtained as the level of treatment increases, and it is possible
to add more contamination to the environment by increased energy con-
sumption than is removed from the wastewater. Comparisons of energy
requirements for a 100 mgd capacity system employing conventional
secondary, advanced wastewater treatment and land treatment systems
were presented. Energy implications with regard to wastewater reuse
were considered, and it was shown that in many instances the reuse of
wastewater can conserve energy. The savings are related to the degree
of treatment required before reuse. Table 2 is a summary of total
energy requirements for various wastewater treatment systems assumed by
Hagan and Roberts for direct discharge of the wastewater, employed for
various reuse purposes, and the energy requirements for alternative
sources of fresh water. Their assumptions include unnecessarily stringent
preapplication treatment requirements for the general case of irrigation
reuse. Current EPA guidance on the topic is presented in the Results and
Discussion section.
Garber et al. (1975) compared biological and physical-chemical
processes to treat wastewater in the Los Angeles area. Biological
processes were found to be more energy efficient and less stressful
on the overall environment. Treatment of the wastewater by physical-
chemical methods required almost five times as much energy as activated
sludge including nitrification and phosphorus removal. Solids disposal
by pumping 90 to 100 miles to the desert to drying beds required 16
times as much energy as the present system of discharging screened
digested solids seven miles at sea. Chemical treatment of the sludge
followed by mechanical dewatering and disposal at local landfills
required 35 times as much energy as the current sludge disposal system.
The general problems associated with small wastewater treatment
plants, alternative treatment processes available to small plants, im-
portant design considerations, and an economic comparison of the alter-
natives available were presented by Benjes (1978). Table 3 presents the
estimated annual energy required alternative wastewater treatment pro-
cesses for a range of design flows. Tchobanoglous (1974) conducted a
similar analysis and cost factors derived from his work are shown in
Table 4.
Jacobs (1977) discussed various ways to more effectively utilize
energy at wastewater treatment plants. Use of different types of
pumps, sludge dewatering equipment, plant modification and energy
recovery from digester gas and incineration of sludge were discussed.
-------
Table 2. Examples of systems to be considered in evaluating energy
implications of wastewater reuse (Hagan and Roberts, 1976).'
Type of reuse
1. Local irrigation (assume 100-ft head for
conveyance)
2. Distant irrigation (assume 1,500-ft head for
conveyance)
3. Industrial (assume 100-ft head)
4. Unrestricted (assume 500-ft head)
Treatment assumed prior to reuse
For irrigation reuse:
activated sludge
biological-chemical
For industrial reuse:
biological-chemical
biological-chemical & desalting
tertiary
tertiary & desalting
For unrestricted reuse:
tertiary
tertiary & desalting
Alternative sources of fresh water
1. Local supplies
2. Imported
3. Desalted seawater
Total
Energy
Required
for 100 mgd
kwh/day
Treatment assumed for discharge
1. Activated sludge (with chlorination, sludge
digestion and landfill disposal)
2. Biological-chemical (activated sludge with alum
treatment, nitrification/denitrification, sludge
digestion and landfill disposal)
3. Tertiary (activated sludge, coagulation/filtration,
carbon adsorption, zeolite ion-exchange,
recalcination)
93,000
235,000
1,137,000
57,000
615,000
57,000
216,000
93,000
235,000
235,000
695,000
1,137,000
1,597,000
1,137,000
1,597,000
57,000
938,000
6,661,000
Courtesy of Water and Sewage Works, Chicago, Illinois.
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Table 3. Estimated energy (electricity and fuel) for alternative treat-
ment processes (Benjes, 1978).
o
Process
Energy (1000 kwh/yr)
Plant capacity (mgd)
0.1 0.5 1.0 2.0
Prefabricated extended aeration
Prefabricated contact stabilization
Custom design, extended aeration
Oxidation ditch
Activated sludge, anaerobic digestion
Activated sludge, nitrification,
anaerobic digestion
Trickling filter, anaerobic digestion
RBC, anaerobic digestion
RBC, nitrification, anaerobic digestion
139
95
197
134
119
251
31
65
113
_
447
857
647
387
650
126
276
496
_
886
1,901
1,288
764
922
246
566
1,026
_
-
-
2,571
1,525
2,576
485
1,105
2,005
All with aerated grit chamber, chlorination and sludge drying beds.
A comparison of energy requirements and costs for sludge dewatering
equipment is shown in Table 5. Energy requirements and costs for
biological treatment systems are presented in Table 6.
Mills and Tchobanoglous (1974) presented detailed methods for
calculating the energy consumption by the unit operations and processes
used in wastewater treatment. Use of the equations and graphs presented
in the paper is illustrated by examples using two alternative flow
schemes. Detailed results are presented in tabular form and are easily
compared between processes and systems.
Smith (1973) estimated the electrical power consumption by most
conventional and advanced processes used to treat municipal waste-
water on a unit processes basis. Electrical power consumption for
complete plants was estimated by adding the power consumption for the
individual processes. A comparison of electrical power consumption
by wastewater treatment systems was made with other uses.
Estimates of recoverable energy in digester gases were made by
Wesner and Clarke (1978). A discussion of the variation in gas
production with the type sludge was presented.
-------
Table 4. Estimated total annual and unit costs for alternative treatment
processes with a design flow of 1.0 mgd (Tchobanoglous, 1974).a
Process
Imhoff tank
Rotating biological disks
Trickling filter processes
Activated sludge processes
With external digestion
With internal digestion
Stabilization pond processes
Land treatment processes
Slow rate
Basic system
With primary treatment
With activated sludge
With stabilization pond
Rapid infiltration
Basic system
With primary treatment
With activated sludge
With stabilization ponds
Initial
capital
cost
dollars
380,000
800,000
900,000
1,000,000
500,000
250,000
340,000
940,000
1,240,000
590,000
200,000
800,000
1,000,000
450,000
Annual
Capital
41,720
87,832
98,811
109,790
54,895
27,447
37,328
103,302
136,139
64,775
21,958
87,832
109,790
49,405
cost, dollars
0 & M
15,550
57,680
58,480
74,410
48,800
23,680
41,540
81,540
115,950
65,220
25,100
65,100
99,510
48,780
Total
57,270
145,512
157,291
184,200
103,695
51,127
28,859
184,742
252,089
129,996
47,058
152,932
209,300
98,185
Unit
cost
cents/
1000
galb
15.7
39.9
43.1
50.5
28.4
14.0
21.6
50.6
69.1
35.6
12.9
41.9
57.3
26.9
Courtesy of Public Works Journal Corporation, Ridgewood, New
Jersey.
Based on an ENRCC index of 1900.
s\
Capital recovery factor = 0.10979 (15 years at 7 percent).
-------
Table 5. Energy comparison of sludge dewatering equipment (Jacobs, 1977).c
Belt press filters
Vacuum filter
Centrifuges
kw Demand
cost /mo.
40.0 kw
$112.00
75.5 kw
$210.00
108.0 kw
$299.60
kwh Usage
cost /mo.
6105 kwh
$153.85
8750 kwh
$220.50
13,700 kwh
$313.05
Monthly
cost
$265.85
$430.50
$612.65
Annual
cost
$3190.20
$5166.00
$7351.80
Notes:
1. Based on dewatering 75,000 Ib/week of waste activated sludge at 3
percent feed, and approximately 20 percent cake solids concentration.
2. Costs based on varying rate schedule.
r\
Courtesy of Water and Sewage Works, Chicago, Illinois.
fi T") r*
Table 6. Energy comparison of biological treatment systems ' * (Jacobs,
1977).f
kw demand
Cost
kwh usage
Cost
Monthly cost
Annual cost
Completely
mixed
ASe
550
$ 1,070
230,000
$ 3,423
$ 4,498
$53,976
Extended
aeration
ASd>e
540
$ 1,053
236,000
$ 3,498
$ 4,542
$54,504
Carousel
extended
aeration
ASd»e
525
$ 1,053
218,000
$ 3,282
$ 4,335
$52,020
Pure
oxygen
AS
525
$ 1,020
216,000
$ 3,247
$ 4,076
$48,804
Bio-Disk
$
188
$ 2
$ 3
$42
425
800
,000
,701
,501
,012
Comparison based on entire plant energy consumption.
Includes consideration of differences in sludge quantity and
characteristics.
c
Costs based on varying rate schedule.
Result in higher effluent quality.
g
Activated sludge.
Courtesy of Water and Sewage Works, Chicago, Illinois.
-------
METHODS AND PROCEDURES
Equation Development
The graphs presented by Wesner et al. (1978) were converted to
lines of best fit at the lower design flow rates (0.1 - 5.0 mgd) and
used to calculate the energy requirements for small systems such as
those employed at military installations. Least-squares fits of the
linear and curvilinear lines were employed. A power function was used to
fit the linear lines on the log-log plots and a polynomial equation was
used to fit the curvilinear lines. The forms of the two functions are
shown below.
log Y = a + b (log X) + c (log X)2 + d (log X)3
Polynomial function
Y = a X Power function
Various combinations of the unit operations and processes were
selected to form the most commonly used wastewater treatment systems.
Energy requirements for each component of the system for various design
flow rates were estimated using the equations of best fit. These results
were tabulated for easy comparison between various types of treatment
systems.
Design Parameters
Design parameters for all of the unit operations and processes
are shown with the energy equations for each operation or process in
Appendix A. Additional detail can be obtained by referring to the
report by Wesner et al. (1978). The energy relationships for the conven-
tional and advanced wastewater treatment processes are unmodified,
but it was necessary to modify the land application energy relation-
ships to conform to accepted practice in cold regions. The slow rate
and overland flow application seasons were modified from five months
per year to 250 days per year to more realistically reflect actual
practice. Rapid infiltration application seasons extend over 365 days
per year .and not five months per year as shown in the Wesner et al.
(1978) report.
Wastewater Characteristics
Raw wastewater and sludge characteristics used to develop the
energy relationships are presented in Appendixes B and C, respectively,
-------
Energy Recovery
The potential energy available in digester gas was estimated using a
figure of 6.5 million Btu/million gallons of wastewater treated. This
value is based upon a mixture of primary and waste activated sludge, and
the value will vary with the type of sludge and must be adjusted when
better data are available. However, a value of 6.5 million Btu/million
gallons of wastewater is satisfactory for estimating purposes and will
yield a conservative estimate for net energy consumption.
Btu available in digester gas can be converted to electricity,
and a conversion factor of 11,400 Btu per kwh can be used to estimate
the electricity generated. The conversion factor assumes an electrical
generation efficiency of 30 percent. The gas utilization system also
requires energy and this must be considered when comparing systems.
Secondary Energy
Secondary energy requirements are the amounts of energy needed
to produce consumable materials used in a wastewater treatment system.
Disinfectants, coagulants, sludge conditioning chemicals and regeneration
of activated carbon and ion exchange resins require energy in their
production, and this energy must be considered when comparing the energy
efficiency of various systems.
Methods of construction, materials of construction, seasonal varia-
tions and other factors also influence the energy budget for a treatment
system, but to a lesser degree than the primary factors such as direct
energy consumption on a daily basis. Only the direct energy consumption
and the secondary energy requirements are considered in this report.
10
-------
RESULTS AND DISCUSSION
Energy Equations
The equations of the lines of best fit for the energy require-
ments of the unit operations and processes used in wastewater treat-
ment based on the graphs reported by Wesner et al. (1978) are presented
in Appendix A. Design conditions and assumptions used in developing
the graphs are presented along with each equation. Details about the
conditions imposed upon the equations can be obtained from the Wesner
et al. (1978) report. Each equation is cross referenced to the Wesner et al,
report. The equation number used in Appendix A coincides with the
figure number in the Wesner et al. report; i.e., Equation 3-15 cor-
responds to Figure 3-15. Only the portions of the curves below a flow
rate of 5 mgd were used to determine the line of best fit. This was
done to obtain a better trend at the lower flow rates of interest rather
than introduce the influence of the higher flow rates. All equations
for the linear lines have a correlation coefficient of 0.999 or better.
Treatment Systems
Flow diagrams of the wastewater treatment systems commonly employed
are shown in Figures 2 through 12. The flow diagrams for land appli-
cations systems were selected utilizing the preapplication treatment
guidelines shown in Table 7. The biological and physical treatment
systems shown in Figures 2, 3, 4, 7, 8, 9, 10, and 11 are most often
employed in small systems; however, the activated sludge process with
sludge incineration (Figure 5), physical-chemical treatment (Figure
6), and the advanced treatment following secondary treatment (Figure
12) have been employed in special cases. These 11 systems can be modified
by adding various processes in the treatment train to produce almost any
quality effluent desired. Also, a very wide range of energy consumption
can be experienced with these basic systems and their modifications.
The raw wastewater characteristics and the expected effluent quality
from each of the systems are shown on the figures. The raw water charac-
teristics are also summarized in Appendix B. Sludge characteristics used
to develop the energy relationships in Wesner et al. (1978) and this
report are presented in Appendix C.
Energy Consumption
Energy requirements for the components of the treatment systems
shown in Figures 2 through 12 for various flow rates of wastewater
treated by the systems are presented in Tables 8 through 19. The table
11
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Table 7. Guidance for assessing level of preapplication treatment for
land treatment systems (EPA, 1978).
I. Slow-rate systems (reference sources include Water Quality
Criteria 1972, EPA-R3-73-003, Water Quality Criteria EPA 1976, and
various state guidelines).
A. Primary treatment - acceptable for isolated locations with
restricted public access and when limited to crops not for
direct human consumption.
B. Biological treatment by lagoons or inplant processes plus
control of fecal coliform count to less than 1,000 MPN/100 mla
acceptable for controlled agricultural irrigation except for
human food crops to be eaten raw.
C. Biological treatment by lagoons or inplant processes with
additional BOD or SS control as needed for aesthetics plus
disinfection to log mean of 200/100 ml (EPA fecal coliform
criteria for bathing waters) - acceptable for application in
public access areas such as parks and golf courses.
II. Rapid-infiltration systems
A. Primary treatment - acceptable for isolated locations with
restricted public access.
B. Biological treatment by lagoons or inplant processes - accept-
able for urban locations with controlled public access.
III. Overland-flow systems
A. Screening or comminution - acceptable for isolated sites with
no public access.
B. Screening or comminution plus aeration to control odors during
storage or application - acceptable for urban locations with
no public access.
probable number of coliform bacteria per 100 ml of sample.
number corresponds to the figure number; i.e., Table 8 is a listing of the
energy requirements for a trickling filter treatment system with anaerobic
digestion (Figure 2). The last column in each table lists the equations
used to calculate the values (Appendix A).
Table 20 shows the energy requirements for components frequently
appended to secondary treatment systems to produce a better quality
effluent. By modifying the basic systems shown in Figures 2 through
12, it is possible to develop the energy requirements for almost any
23
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system applicable to the treatment of small flows of wastewater. For
combinations not shown in the. tables, energy requirements can be calcu-
lated using the equations in Appendix A.
Carbon and Ion Exchange Regeneration
Energy requirements for the regeneration of carbon and ion ex-
change materials for very low flow systems (0.05 -0.1 mgd) are shown
in Tables 12, 19, and 20 only for comparative purposes. In most cases
activated carbon would be replaced rather than regenerated and the
energy requirements would be reduced accordingly. The regeneration of
ion exchange resins would probably be justified, but depending upon
local conditions it may be less expensive to replace ion exchange resins
on a fixed schedule rather than to regenerate them.
Energy requirements for carbon regeneration represent less than
3 percent of the electricity and 94 percent of the fuel consumed in
the components of an advanced treatment system following secondary
treatment at a flow rate of 5 mgd. At a flow rate of 0.05 mgd, the
energy requirements for carbon regeneration have been reduced to 2
percent of the electricity and 57 percent of the fuel requirements.
However, the inconvenience of operating additional equipment and the
need for highly skilled operation would probably rule out the use of
carbon regeneration at very small (< 0.5 mgd) wastewater treatment
systems.
Gas Utilization
Although the energy required and produced by gas utilization is
presented in the examples summarized in Tables 8, 9, and 10, gas utiliza-
tion in small flow systems, particularly at the lower flow rates of less
than 0.5 mgd, may not be advisable. The increased operating expense
caused by the need for a more skilled operator and more sophisticated
equipment will likely offset any savings from gas utilization. However,
this is a decision that must be made on an individual basis.
Effluent Quality and Energy Requirements
Table 21 shows the expected effluent quality and the energy
requirements for various combinations of the operations and processes
shown in Figures 2 through 12 and Tables 8 through 20. Energy require-
ments and effluent quality are not directly related. Utilizing facul-
tative lagoons and land application techniques, it is possible to ob-
tain an excellent quality effluent and expend small quantities of energy.
Although one system may be more energy efficient, the selection of a
wastewater treatment facility must be based upon a complete economic
analysis. However, with rising energy costs, energy requirements are
assuming a greater proportion of the annual cost of operating a waste-
water treatment facility, and it is likely that energy costs will
37
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become the predominant factor in the selection of small flow treatment
systems. Operation and maintenance requirements, and consequently costs,
are frequently kept to a minimum at small installations because of the
limited resources and operator skills normally available. This favors
the selection of systems employing units with low energy requirements.
It is very likely that all future wastewater treatment systems at small
installations in isolated areas will be designed employing low energy
consuming units and simple operation and maintenance. The only exceptions
to this will be in areas with limited space or construction materials, or
where surplus energy is available.
The effluent quality expected with each of the treatment systems and
the energy requirements shown in Table 21 are presented in the order of
decreasing BOD5 concentration in the effluent. The other parameters
(suspended solids, Total P, and Total N) do not necessarily decrease in
the same manner because most treatment facilities are designed to remove
BOD5, but in general there is a trend in overall improvement in effluent
quality as one reads down the table. As shown in Table 21, there are
many systems available to produce an effluent that will satisfy EPA
secondary or advanced effluent standards; however, energy requirements
for the various systems are varied and can differ by a factor of greater
than 20 to produce the same quality effluent.
For purposes of comparison the total energy (electricity plus fuel:
3,413 Btu/kwh) for a typical 1 mgd system has been extracted from Table 21
and listed in Table 22 in order of increasing energy requirements. It is
quite apparent from Table 22 that increasing energy expenditures do not
necessarily produce increasing water quality benefits. The four systems
at the top of the list, requiring the least energy, produce effluents
comparable to the bottom four that require the most. Three of the top
four are land treatment systems, and their adoption will depend on local
site conditions. The facultative pond followed by intermittent sand
filter and surface discharge to receiving waters is less constrained by
local soil and groundwater conditions.
Conventional Versus Land Treatment
A comparison of the energy requirements for a conventional waste-
water treatment system consisting of a trickling filter system followed
by nitrogen removal, granular media filtration and disinfection with a
facultative pond followed by overland flow and disinfection is shown in
Figure 13. This comparison is made because of the approximately equivalent
quality effluents produced by the two systems (Table 21). The relation-
ships in Figure 13 clearly show that there are significant electricity
and fuel savings with the land application system. Similar comparisons
for modifications of the two systems can be made by referring to Tables
8, 17, and 20 and selecting combinations to produce equivalent effluents.
Figure 14 shows a comparison of the energy requirements for an
activated sludge plant producing a nitrified effluent, followed by
39
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1100
1000
900
800
700
600
500
400
300
200
100
Trickling Filter
+
Nitrogen Removal
(Ion Exchange)
+
Granular Media Filt.
(Gravity)
Disinfection
Overland Flow
(Flooding)
- 8
- 7
- 6
- 5
- 4
- 3
- 2
10
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U.
FLOW RATE, MOD
Figure 13. Comparison of energy requirements for trickling filter ef-
fluent treated for nitrogen removal and filtered versus
facultative pond effluent followed by overland flow
treatment.
40
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2400 _
2100 _
1800 .
o
x
1500
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900
600 _
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FueK
^ i-a
FLOW RATE, MOD
Figure 14. Comparison of energy requirements for activated sludge,
nitrification, filtration and disinfection versus facultative
pond effluent followed by rapid infiltration and primary
treatment followed by rapid infiltration.
41
-------
Table 22. Total annual energy for typical 1 mgd system (electrical plus
fuel, expressed as 1000 kwh/yr).
Treatment system
Rapid infiltration (facultative pond)
Slow rate, ridge + furrow (fac. pond)
Overland flow (facultative pond)
Facultative pond + interm. filter
Facultative pond 4- microscreens
Aerated pond 4- interm. filter
Extended aeration 4- sludge drying
Extended aeration 4- interm. filter
Trickling filter 4- anaerobic digestion
RBC 4- anaerobic digestion
Trickling filter 4- gravity filtration
Trickling filter 4- N removal + filter
Activated sludge 4- anaerobic digestion
Activated sludge 4- an. dig. 4- filter
Activated sludge 4- nitrification 4- filter
Activated sludge + sludge incineration
Activated sludge + AWT
Physical chemical advanced secondary
Effluent quality
BOD
5
1
5
15
30
15
20
15
30
30
20
20
20
15
15
20
<10
30
SS P
1 2
1 0.1
5 5
15
30
15
20
15
30
30
10
10
20
10
10
20
5 <1
10 1
N
10
3
3
10
15
20
-
-
-
-
-
5
-
-
-
-
<1
—
Energy
1000
kwh/yr
150
181
226
241
281
506
683
708
783
794
805
838
889
911
1,051
1,440
3,809
4,464
granular media filtration and disinfection; a facultative pond followed
by rapid infiltration land treatment, and primary treatment followed by
rapid infiltration land treatment is the most energy-efficient waste-
water treatment system, but it is closely followed in energy efficiency
by the primary treatment and rapid infiltration system. The energy
requirements for both of the rapid infiltration land treatment alter-
natives are less than 15 percent of the energy required for the activated
sludge system.
In Figure 15, energy requirements for slow rate land application
systems using ridge and furrow and center pivot systems to distribute
facultative pond effluent are compared with the energy requirements for
an activated sludge plant practicing nitrogen and phosphorus removal,
granular media filtration of the effluent, and disinfection prior to
discharge. Both the activated sludge and advanced treatment system and
the facultative pond and slow rate systems produce approximately equiva-
lent quality effluents. The ridge and furrow flooding technique of land
treatment requires less than 5 percent of the energy required by the
advanced treatment scheme. Utilizing a center pivot mechanism to distri-
bute the facultative pond effluent increases the energy requirements by a
42
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9600
8400
10
b
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r- 6000
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UJ
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IT
4000
— 3600
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2400
1200
Electricity-
Activated Sludge
Nitrogen Removal
(Ion Exchange)
Phosphorus Removal
Granular Media Filtration
(Gravity)
Facultative Pond
+
Slow Rate Land Treatment
Ridge & Furrow -Flooding
32
28
10
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24
03
Z
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20
12
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2
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ac
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Figure 15.
12345
FLOW RATE,MGD
Comparison of energy requirements for secondary treatment
followed by advanced treatment versus facultative pond ef-
fluent followed by slow rate land treatment.
43
-------
factor of five compared with the ridge and furrow flooding technique, but
the energy requirements for the center pivot system are less than 11 per-
cent of the energy requirements for the advanced treatment system.
In an energy conscious environment, the land application techniques
of treating wastewater have a distinct advantage over the more conven-
tional wastewater treatment systems. When land is available at a reason-
able cost, the lower energy requirements for land application systems will
likely result in a more cost effective as well as more energy effective
system of wastewater treatment.
44
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CONCLUSIONS
Based upon the results of the analyses presented in this report, the
following conclusions are made.
1. With increasing energy costs, energy consumption is assuming a
greater proportion of the annual cost of operating wastewater
treatment facilities of all sizes, and because of this trend,
it is likely that energy costs will become the predominant
factor in the selection of cost-effective small-flow wastewater
treatment systems.
2. Small-flow wastewater treatment systems are frequently designed
to minimize operation and maintenance, and as energy costs
increase, design engineers will tend to select low-energy-
consuming systems.
3. Low-energy consuming wastewater treatment systems are generally
easier to operate and maintain than energy intensive systems,
making the low-energy-consuming systems even more attractive
because of the desire to minimize highly skilled operation at
small facilities.
4. Where suitable land and groundwater conditions exist, a facul-
tative pond followed by rapid infiltration is the most energy-
efficient system described in this report.
5. When surface discharge is necessary and impermeable soils exist,
a facultative pond followed by overland flow is the second most
energy-efficient system described in this report.
6. Facultative ponds, followed by slow or intermittent sand filters,
are the fourth most energy-efficient systems discussed, and are
not limited by local soil or groundwater conditions.
7. Physical-chemical advanced secondary treatment systems utilize
the most energy of the conventional methods of producing an
effluent meeting of federal secondary effluent standard of
30 mg/1 of BOD,- and suspended solids.
8. Slow rate land application systems following facultative ponds
are more energy efficient than most forms of mechanical secondary
treatment r^vstems, while also providing benefits of nutrient
removal, recovery and reuse. ^
9. Advanced physical-chemical treatment following conventional
secondary treatment consumes approximately 34 times as much
electrical energy and 13 times as much fuel as slow rate land
treatment to produce an equivalent effluent.
45
-------
10. Land application wastewater treatment systems following storage
ponds (aerated or facultative), preliminary treatment (bar
screens, comminutors, and grit removal), or primary treatment
are by far the most energy-efficient systems capable of
producing secondary effluent quality or better.
11. This study did not consider the energy requirements for produc-
tion of all materials consumed in the treatment process, but it is
not believed that inclusion of such factors would significantly
change the relative ranking of the systems discussed. Such
inclusion would rather make the differences between simple
biological processes and mechanical systems even more dramatic.
46
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APPENDIX A
EQUATIONS DESCRIBING ENERGY REQUIREMENTS
t Iglltl'
Numne
Krom E['.\
430/9-"" Jll
)peralion, Process, and Equation
Energy Requirements
Design (ondit j ons, AssumiH ions and
Et fluent Quality
Raw Sewage Pumping (Constant Speed)
Y - 197,000 X
Y -- 123,000 X*
Y = 61,100 X
Y = 19,400 x'
,0.93
,0.93
0.93
0.93
TDH = 100 ft
IDH = 60 ft
TDH = 30 ft
TDH = 10 ft
TDK = i ft
Y = 9,660 X
Y = Electrical Energy Required, kwh/yr
X = Flow, mgd
Raw Sewage Pumping (Variable Speed)
0 94
Y = 69,000 X TDH = 30 ft
0 94
Y = 24,100 X TDH - 10 ft
Y = 10,800 X°'96 TDH = i ft
Y = Elet tiTical Energy Required, kwh/yr
X = Flow, mgd
Raw Sewage Pumping (Variable Speed)
V0.94
Y - 229,000 X TDH = 100 ft
Y = 152,000 X°'95 TDH = 60 ft
Y = Electrical Energy Required, kwh/yr
X = Flow, mgd
Lime Sludge Pumping
log Y -- 3.4788 + 0.7475 (log X) + 0.1906 (log X)"
-.0.0101 (log X) - Raw Sewage, Low i_ime
log Y = 3.4448 + 0.7273 (log X) + 0.1714 (log X)~
- 0.0515 (log X)3 - Raw Sewage, High Lime
log V = 3.3983 + 0.7173 (log XI + 0.1872 (log X)"
- 0.0532 (log X) - Si-> nndar\ Efflueni. Low Lime
log Y = 3.4676 + 0.7619 (log X) 4- '-. .842 (log X)2
- 0.0614 (log X) - Secondarv Effluent, High Lime
Y = Electrical Energy Required, kwh'vi
X = Plant Capacity, mgd
n S1udge Pumping
0 95
4,000 X ' (Secondar> hffluent)
sewage)
Y = r.leL I r ica] t'nergv Required, kwi
^ - Plant Capacity, mgd
Design Assumptions:
Efteeiencies !or LypiLcil ent r if ugal
pumps (varies with fio \
Variahle level wet well
TDH is total dynamic heat1
Type of Energy Required • t- leet r n al
Design Assumptions:
Efficiencies for typical centrifagai
pumps (varies with flow)
Wound rotar variable speed
Variable level wet we 11
Type of Energy Required: Kle< 11 ica1
Design Assumptions:
Efficiencies for typK al tent r it ug«
pumps (varies with flowl
Wound rotor variable t,peed
Varib1e le^ei wet we 11
Type of Energy Required Fleetri> •
Design Assumptions:
TDH 25 ft
Operating Paramo te rs:
SI udge c once nt rat ions, ,-,et ondary
t reatment . a re 5% 'or low 1ime
and 7.57, lor h igh lime
S J udge (.omentrations, te r 11 ,iry
t rent men t , are 3% for 1 ow 1 ime
and 4.5' for high 1ime
Type of Em rgv Ret aired : I [ i t r 11 a
Water Qua] ity Inf luem f- 1 I IHMK
( Secondary 1 (mg/ 1 ' Ung/ 1 )
Suspended Solids 250 10
Ph.v,pliat i- is P II .0
Design As s i imp t ions:
IDH = 2 - t L
Sludge on entr.itnm (.set onda i v)= I
^ I udge > OIH ent r it ion ( tert i ir\ i- (•
S, e Wesner
47
-------
Figure
Number
From EPA
430/9-77-011
Operation, Process, and Equation Describing
Energy Requirements-
Design Conditions, Assumptions and
Effluent Quality
3-6 Ferric Chloride Sludge Pumping
log Y = 3.6192 + 0.8308 (log X) + 0.1364 (log X)2
- 0.0356 (log X)3 - Secondary Effluent
log Y = 3.6051 + 0.8078 (log X) + 0.1301 (log X)2
- 0.0047 (log X) - Raw Sewage
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Water Quality:
(Secondary)
Suspended So]ids
Phosphate as P
Water Quality:
(Tertiary)
Suspended Solids
Phosphate as P
Influent
(mg/1)
250
11.0
Influent
(mg/D
30
11.0
Effluent
(mg/1)
30
1.0
Eftluent
(mg/1)
10
1.0
Design Assumptions:
TDH = 25 ft
Sludge concentration (secondary) = 27,
Sludge concentration(tertiary)= VI
Operating Parameters:
Ferric Chloride addition = 85 mg/1
Type of Energy Required: Electrical
Mechanically Cleaned Screens
log Y = 3.0803 + 0.1838 (log X) - 0.0467 (log X)2
+ 0.0428 (log X)3
Y = Electrical Energy Required, kwh/yr
X = Flow, mgd
Design Assumptions:
Normal run times are 10 mm total
time per hr except 0. 1 tngd (5 mm)
and 100 mgd (15 min)
Bar Spacing is 3/4 in
Worm gear drive, 50% efficiency
Type of Energy Required: Eleitrical
3-8 Comminutors
log'Y - 3.6704 + 0.3493 (log X) + 0.0437 (log X)'
+ 0.0267 (log X)3
Y = Electrical Energy Required, kwh/yr
X = Flow, mgd
Type of Energy Required: Elee tnea 1
3-9 Grit Removal (Aerated)
log Y = 4.1229 + 0.1582 (log X) + 0.1849 (log X)2
+ 0.0927 (log X)3
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Water Quality:
Removal of 90% of materia1 with a
specific gravity of greater than
2.65
Design Assump turns:
Grit removal to a holding fatuity
by a screw pump
Size based on a peaking factor of 2
Detention time is 3 mm
Tank design similar to that by
Link-Belt, FMC Corp. or Jeffrey
Operating Parameters:
Air rate of J cfm per foot ot length
Removal equipment
Type of Energy Required: i: 1 et t ri L a .1
3-10 Grit Removal (non-Aerated)
Y - 530 X°-24
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Pre-Aeration
log Y = 4.5195 + 0.7785 (log X) + O.J618 (log X)2
- 0.0496 (log X)3
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Water Qua.lity:
Removal of 90% of material with
specific gravity greater th.in 2,65
Design Assumptions :
Grit removal to a hold nig facility
by screw pump
Size based on peak ing i ai to r ot 2
Square tank
Sma 1 le^t vo lume is 11 i n ! 1
Velocity of 0.55 t ps through ^quar,
tank or 1 mm detention t ime it
average t low
Operate equipment 2 hr eat li t! iv
Type ot Energy Kequ i red : 1, 1 1 i t r 1 1 1 1
Design Assumpt ion:
Detention time is 20 mm
Ope rat ing Par a mete r :
ALr supply is 0.15 cu it/^al
Type of Energy Required: I let tri
48
-------
Figure
Number
From EPA
430/9-77-011
Operation, Process, and Equation Describing
Energy Requirements
Design Conditions, Assumptions and
Effluent Quality
3-12 Primary Sedimentation
log Y = 3.8564 + 0,3781 (log X) + 0.1880 (log X)2
+ 0.0213 (log X) - Rectangular
log Y = 3.8339 + 0.3362 (log X) + 0.0148 (log X)2
+ 0.0081 (log X)3 - Circular
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
3-13 Secondary Sedimentation
log Y = 4.2149 + 0.6998 (log X) + 0.1184 (log X)2
- 0.0660 (log X)3 - Activated Sludge
log Y = 3.8591 + 0,3349 (log X) + 0.0735 (log X)2
+ 0.0238 (log X)3 - Trickling Filter
Y = Electricity Required, kwh/yr
X = Plant Capacity, mgd
Chemical Treatment Sedimentation Alum or Ferric Chloride
log Y = 3.5364 + 0,0743 (log X) + 0.0290 (log X)2
- 0.0144 (log X)3
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Water Quality:
BOD5
Suspended Solids
Influent Lftluem
(mg/1) (mg/1)
136
80
210
230
Design Assumptions:
Sludge pumping included
Scum pumped by s]udge pumps
Multiple tanks
Operating Parameters:
Loading = 1000 gpd/sq ft
Waste rate - 65% of influent Solids,
5£ concentration
Pumps operate 10 minutes of eai_h hr
Type of Energy Required: Electric, al
Water Quality: Eftlaent
(mg/1)
BOD5 20
Suspended Solids 20
(applicable to ac tivated s1udge sys-
tem effluent quality variable for
trickling filter systems)
Design Assumptions:
Secondary sedimentation for ionven-
tional activated sludge im ludes
return and waste activatcd siudgt
Secondary sedimentation for t r i ck1ing
filter system includes waste sludge
pumping^
Hydraulic Ioading = 600 gpd/sq ft
Operating Paramete rs:
Waste activated sludge
= 0.667 Ib ss/lb BOD5
Return activated siudge = 50% Q
Sludge concentration = 1%
Waste pumps: operated 10 minutes
each hour
Type of Energy Required: li! lei tr u ,11
Design Assumptions:
Coagulant: alum or ferric i h 1 or idt:
Operating Parame ter.
Overflow rate = 700 gpd/sq ft
Type of Energy Required: me<.tru,il
3-16
Chemical Treatment Sedimentation Lime
log Y = 3.5144 + 0.0172 (log X) + 0.0942 (log X)2
+ 0.0905 (log X)3
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
High Rate Trickling Filter (Rock Media)
Y = 61,300 X°'94
Y = Electrical Energy Required, kwh/yr
X - Plant Capacity, mgd
Design Assumptions:
Coagulant: Lime
Overflow rate, Avg = 1,000 ^pd
Type ol Energy Required: !•; lert
Water Quality:
BOD5
Suspended Sol ids
80
Design Assumptions •
Hydraul it 1 o.uling = 0 . 4 ;;i>m/s(| t 1
int 1uding ret ircu1 ai
TDH = 10 t t
Operating Parameter:
Rec i rt u Lai i on K.i t 10 = 2:1
Type nf Energy Required: I I IM
i I
49
-------
Figure
Number
From EPA
430/9-77-011
Operation, Process, and'Equation Describing
Energy Requirements
Design Conditions, Assumpt ions ,md
Effluent Quality
Influent Effluent
cm«/n (mg/O
30
30
3-17 Low Rate Trickling Filter (Rock Media)
0 94
Y = 93,600 X
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
136
80
Water Quality:
BOD5
Suspended Solids v«
Design Assumpt ions:
Hydraulic loading = 0.04 gpm/sq
TDH = 23 ft
Operating Parameter:
No recirculation
Type of Energy Required: Electrical
ft
3-18 High Rate Trickling Filter (Plastic Media)
Y = 161,000 X°'95
Y - Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Water Quality: Influent Effluent
(mg/1) (mg/1)
BOD5 136 35-45
Suspended Solids 80 35-45
Design Assumptions:
Hydraulic loading= 1.0 gpm/sq ft
including recirculation
TDH = 40 ft
Operating Parameter:
Recirculation Ratio =5:1
Type of Energy Required: Electrical
3-19 Super - High Rate Trickling Filter (Plastic Media)
n Q Q
Y = 224,000 X
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Water Quality: Influent Effluent
(mg/1) (mg/1)
BOD5 136 82
Suspended Solids 80 48
De s i gn As s ump 11 on s:
Hydraulic loading = 3 gpm/sq ft.
including recirculation
TDH = 40 ft
Operating Parameter:
Recirculation ratio =2:1
Type of Energy Required: Electrical
3-20 Rotating Biological Disk
1 0?
Y = 110 ,000 X - Standard Media
Y = 73,000 X1'00 - Dense Media
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Activated Biofilter
i no
Y = 210,000 X
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Water Quality: Influent Effluent
(mg/1) (mg/1)
BOD5 136 30
Suspended Solids 80 30
Design Assumptions:
Hydraulic loading = 1 gpd/sq ft
Standard media = 100,000 sq ft per
unit
Dense media = 150,000 sq ft per unit
Type of Energy Required: Electrical
Water Quality: Influent Effluent
(mg/1) (mg/1)
BOD * 136 20
Suspended Solids 80 20
Design Assumptions:
Bio-cell loading=200 Ib BOD5/1000
cu ft
Aeration = 1 Ib 02/lb BOD5
Oxygen transfer efficiency in W.KSLC-
water (mechanical aeration)
= 1.8 Ib 02/hp-hr
Operating Parameters:
Recirculation = 0.9:1
Recycle sludge = 50%
Type of Energy Required: Klei tru ,i 1
3-22
Brush Aeration (Oxidation Ditch)
Y =• 430,000 X
1.00
Electrical Energy Required, kwh/yr
Plant Capacity, mgd
Water Quality: Influent
(mg/l)
BOD5 136
Suspended Sol ids 80
Design Assumpt ions:
Oxygen transfer effLcieiuy
02/hp-hr (wire to wntor)
Operating Parameti1 r:
Oxygen reqm rement = 1.5 II)
i-onsumed/lb B01>5 removed
02 consumed/Ih NH^-N (in
feed) oxidized
Type of Energy Required : I I LM
50
-------
Figure
Number
From EPA
430/9-77-011
Operation, Process, and Equation Descrj.bi.ng
Energy Requirements
Design Conditions, Assumptions jnd
Effluent Quality
3-23
Oxygen Activated Sludge - Uncovered Reactor With
Cryogenic Oxygen Generation
Water Quality:
Ei fluent
Y = 201,000 X
1.00
Unstaged, plug flow 0? activated
sludge and complete mix 02
activated sludge
10
20
Electrical Energy Required, kwh/yr
Plant Capacity, mgd
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Influent
(ing/1)
BOD5 136
Suspended Solids 80
Design Assumptions:
Oxygen transfer efficiency = 1.5* Ib
02/hp-hr (wire to water)
Rotating fine bubble diffusers'for
dissolution
Includes oxygen generation
Operating Parameter:
Oxygen requirement = 1.1 Ib 02
consumed/lb BOD5 removed
Type of Energy Required: Electrical
3-24 Oxygen Activated Sludge - Covered Reactor
With Cryogenic Oxygen Generation
1 00
Y = 170,000 X • U
Water Quality:
BOD5
Suspended Solids
Influent
(mg/1)
136
80
Effluent
(mg/1)
20
20
Design Assumptions:
Oxygen transfer efficiency in waste-
water = 2,07 Ib 02/hp-hr (wire tr
water)
Surface aerators for dissolution
Includes oxygen generation
Operating Parameter:
Oxygen requirement = 1.1 Ib 0?
supplied/lb BOD,- removed
Type of Energy Required: Electrical
3-25 Oxygen Activated Sludge - Covered Reactor
With PSA Oxygen Generation
1 00
Y = 230,000 X
Water Quality:
BOD5
Suspended Solids
Influent
(mg/1)
136
80
Effluent
(mg/1)
20
20
Design Assumptions:
Oxygen transfer efficiency in waste-
water = 1.53 Ib 02/hp-hr (wire to
water)
Surface aerators for dissolution
Includes oxygen generation
Operating Parameter:
Oxygen Requirement = 1.1 Ib 02
consumed/lb BOD5 removed
Type of Energy Required: Electrical
3-26 Activated Sludge -
Y
Y
Y
- 290
= 600
- 350
,000
,000
,000
i
X
x1
1
x1
.00
.00
.00
Coarse Bubble Diffusion
Conventional activated sludge
(complete mix)
Extended aeration
Contact stabilization
Water Quality:
BOD5
Suspended Solids
Influent
(mg/D
136
80
Design Assumptions:
Oxygen transfer ef f ir iency
water = 1.08 Ib
02/hp-hr
Effluent
(mg/1)
20
20
In wnste-
(wire to
water, including blower)
Average value for all types of
diffusers
Operating Parameters:
Conventional activated si udge oxygL-n
requirement = 1.0 Ib 02
consumed/lb 0005 removed
Extended aeration oxygen requiremenl
= 1.5 Ib 02 consumed/lb BOD5
removed + 4.6 Ib 02 <• onsurocd/! b
NH4-N (in re.utor feed) Oxidised
Contact stabilization oxygen require-
ment = I.I Ib 02 consumed/ Ib BOD^
removed + 4.6 Ib 0^ <• onsumed/ Ib
NH^-N (in reiyi_le sludge) oxuli/u
-------
Figure
Number
From EPA
430/9-77-011
Operation, Process, and Equation Describing
Energy Requirements
440,000 X
240,000 X
1.00
1.00
Extended aeration
Contact stabilization
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Design Conditions, Assumptions and
Effluent Quality
3-27 Activated Sludge -
Y = 230,000 XUO°
Fine Bubble Diffusion
Conventional activated sludge
(complete mix)
Water Quality:
BOD5
Suspended Solids
Influent
(mg/1)
136
80
Effluent
(mg/L)
20
20
Design Assumptions:
Oxygen transfer efficiency in waste-
water = 1.44 Ib 02/hp-hr (wire to
water, including blower)
Average value for all types of
diffusers
Operating Parameters:
Conventional activated sludge oxygon
requirement = 1.0 Ib 02 consumed/lb
BODcj removed
Extended aeration oxygen requirement
= 1.5 Ib 02 consumed/lb 8005 re-
moved + 4.6 Ib 02 consumed/lb
NH^-N (in reactor feed) oxidized
Contact stdbilization oxygen requiri
ment = 1.1 Ib ©2 consumed/lb BOD^
removed + 4.6 Ib 02 consumed/lb
NH^-N (in recycle sludge) oxidized
during aeration
Type of Energy Required: Electrical •
Y = 160,000 X ' Conventional activated sludge
3-28 Activated Sludge Treatment - Mechanical Aeration
Conventional ac
(complete mix)
Y = 350,000 X1'00 Extended aeration
Y = 180,000 X1' ° Contact stabilization
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Water Quality:
Activated Sludge - Turbine Sparger
Y
215,000 X " Conventional activated sludge
(complete mix)
Extended aeration
Contact stabilization
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Y = 430,000 X
Y = 250,000 X1'00
Effluent
(mg/1)
20
20
Influent
(mg/1)
BOD5 136
Suspended Solids 80
Design Assumptions:
Oxygen transfer efficiency
02/hp-hr (wire to water)
Surface aerator, high speed
Operating Parameters:
Conventional activated sludge require-
ment = 1.0 Ib 02 consumed/lb 8005
removed
Extended aerat ion oxygen requirement
» 1.5 Ib 02 consumed/lb BOD5 re-
moved + 4.6 Ib 02 consumed/lb
NH,-N (in reactor feed) oxidized
Contact stabilization oxygen require-
ment = 1.1 Ib 02 consumed/lb BOD^
removed + 4.6 Ib 02 consumed/Ib
NH^-N (in recycle sludge) oxidized
during reaeration
Type of .Energy Required: Electrical
Water Quality:
Influent
(mg/1)
136
80
Effluent
(mg/1)
20
20
Suspended Solids
Design Assumptions:
Oxygen transfer efficiency in wa.ste-
water = 1.6 Ib 02/hp-hr (wire to
water)
Operating Parameters:
Conventiona1 at t tvated siud^e oxygen
requirement = 1.0 Ib 02 consumed/ Ib
BOD^ removed
Extended aeration oxygen requirenk ni
= 1.5 Ib 02 consumed/lb 1101)$ ri -
moved + 4.6 Ib 02 consumed / J t)
reactor feed) oxidazed
oxygen require-
ment = 1.1 Ib 02 consumed/Jb 1101)^
removed + 4.6 Ib 02 ionsumcd/lh
NH^-N (in recy< le .sludge) oxidi/ed
during reaeration
Type of Energy Required: [•" lot L ru a I
NH -N
Contact stabi1ization
52
-------
Figure
Number
From EPA
430/9-77-011
Operation, Process, and Equation Describing
Energy Requirements
Design Condit ions, Assumptlonb and
Hi f1ucnL Quality
3-30
3-31
Activated Sludge - Static Mixer
Y = 250,000 X
1.00
Conventional activated sludge
(complete mix)
1 00
Y = 500,000 X Extended aeration
Y = 300,000 X
Contact stabilization
Y = Electrical Energy Required, kwh/yr
X = Plant capacities, mgd
Water Quality:
BOD5
Suspended Solids
Design Assumptions:
Oxygen transfer eff u- lency = 1.44 Ib
02/hp-hr (wire to water)
Operating Parameters:
Conventional activated s1udge oxygen re-
quirement = 1.0 Ib O'j ( onsi'med/1 b HOlJ-
removed
Fxtended aerj tion oxygen requiremain = I.S
Ib 07 coiisumed/lb BOD^ ie,!ioved 4- 4.6 Ib 0 ,
consumed/Ib NH^-N-N (in reactor feed) oxidi/etl
Contefc t stabil ization oxygen requ 11 uinent -
1.1 Ib 02 uonsumed/lb BOD5 removed -I- 4.6
Ib 02 tonsumed/lb NH^-N (in ri-eyi le-
sludge) oxidized during reaeration
rlype of hnergy Requirement: Elettriial
Activated Sludge - Jet Diffuser
Y = 170,000 X
Conventional activated siudge
(complete mix)
Y = 340,000 X1'00 Extended aeration
Y = 210,000 X1'00 Contact stabilization
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Water Qualit y:
BOD5
Suspended Sol ids
Design Assumptions:
Oxygen t ransfer ef ritiem y in wastewa ter =
1.8 Ib 02/hp-hr (wne to water)
Operating Paramete rs:
Conventional activ.it. ed s 1 udge oxygen re-
quirement = 1.0 Ib 02 consumed/lb BOl)^
removed
Extended aerat ion oxygen requ i re merit. - 1. S
Ib OT consumed/Ib BOD5 removed + 4.6 Ib
02 Lonsumed/lb NH^ -N (in rt-.u tor tued)
oxidized
Contac t s tab i 1 L z.it LOU oxygen requ i ri. menL -
1.1 Ib 0; - onsumt'dMb BOD^ reiiuwed -t- 4.6
Ib 02 consumed/Ib NH^-N (in rciviIe
s ludge) ox i >i i/od dur i ng re ie i ,11 u>n
Typo of Fnergv Required. Electi U a I
3-32 Aerated Ponds
Y = 260,000 X1'00
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Suspended So 1 ids
Design Ass limp t i ons :
Iow-speed moihaniia 1 sur)ate aetat 01 -
Motor e t f it i em y = 90 -'
Aorafor t*ffnicnty =- 1.8 )h 11,'lip-lu fu
to v,ati-r)
1 eel Is - 1st tell aeraU-d
Total detention ti.ni.' 3D days
One rat ing Fa rameter:
Ox> gen > eqnirement - 1.0 1b 0>I\h HOJ }
removed
lype of i.nergy Required' 1 I ei t i u ,1 i
Nitrification - Suspended Growth
Y = 180,000 X1'00
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Ammonia as N
HOD 5
1'es i.gn Assampt ions;
Mochan i k a I aerat i,M, o
eff U'leiu v = 1.8 Ih
wa t e r)
i't,e of I ime h is no s i e
enei g\ i ecpi i remenL
Ope rat ing Parameter
Oxygen ri'qin rement '•*
+ 1.0 1 h 0 i/ Ib BOD,
lype of LniMs\ Kequired:
53
-------
Figure
Number Operation, Process, and Equation Describing
From EPA Energy Requirements
430/9-77-011
Design Conditions, Assumptions and
Effluent Quality
3-34
Nitrification, Fixed Film Reactor
Y - 133,000 X
Recycle = 0.5:1
0 Q2
Y = 151,000 X Recycle = 1:1
Influent
(mg/1)
25
50
Effluent
(mg/1)
2.5
10
Y = 226,000 X
0-92
Recycle = 2:1
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Water Quality:
Ammonia as N
BOD5
Design Assumptions:
No forced draft
Plastic n edia
Pumping TDK = 40 ft
Type of Energy Required: Electrical
Denitrification - Suspended Growth (Overall)
(Includes Methanol addition, reaction,
sedimentation and sludge recycle)
Water Quality:
log Y - 5.0043
- 0.0332 (log X)
0.9495 (log X)
3
0.0248 (log X)
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
3-36 DenicrifIcation - Suspended Growth Reactor
0 99
Y = 72,500 X
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Influent Effluent
(mg/1) (mg/1)
N03-N 25 0.5
De s ign As s ump t i on s:
Methanol - Nitrogen ratio 3:1
Remaining design assumptions and operating
parameters are shown on the following
curves in EPA 430/9-77-011
Denitrification Reactor, Figure 3-36
Reaeration, Figure 3-37
Sedimentation and Sludge Recycle,
Figure 3-3&
Type of Energy Required: Electrical
Design Assumptions:
Temperature = 15°C
Nitrate removal = 0.1 Ib N03-N/lb MLVSS/day
Mixing device, submerged turbines, hp = 0.5
hp/1000 cu ft
Methanol addition is included
Operating Parameter:
MLVSS = 1500 mg/1
Type of Energy Required: Electrical
3-37 Denitrification, Aerated Stabilization Reactor
Y = 32,000 X1'00
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Design Assumpt ions:
Detention time = 50 min
Mechanical aeration -= I hp/1000 cu ft
Type of Energy Required: Electrical
3-38 Denitrification, Sedimentation and Sludge Recycle
log Y = 4.1171 + 0.7596 (log X) + 0.1607 (log X)2
- 0.0389 (log X)^
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Design Assumptions:
Surface loading = 700 gpd/sq ft
Sludge recycle = 50% @ 15 ft TDK
Type of Energy Required: Electrical
3-39
3-40
Denitrification - Fixed Film, Pressure
log Y = 4.4238 + 0.8657 (log X) + 0.0840 (log X)'
+ 0.0097 (log X)3
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Denitrification - Fixed Film, Gravity
log Y = 3.9344 + 0.7310 (log X) + 0.1803 (log X)*
- 0.0453 (log X)3
Y - Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Water Quality: Influent Effluent
(mg/1) (mg/1)
Nitrate as N 25 O.S
Design Assumptions :
Sand media size = 2-4 mm
Influent pumping TDH = 15 ft
Loading rate = 1.7 gpm/sq ft
Temp = I5°C
Depth = 6 ft
Operating Parameters:
Backwash every 2 days for 15 min ^ 25
gpm/sq ft and 25 ft TDH
Methanol addition = 3.1 (CH-jOH: NO j-
Type of Energy Required: Electric, il
Water Quality: Influent Ef t 1 ucnt
(mg/1) (mg/1)
Nitrate as N 25 0.5
Design As sump t ions:
Sand media s i ze = 2- a mm
Depth - 6 ft
Loading rate =1.7 gpm/sq ft
Temperature = 15°C
Operating Parameters:
Backwash 15 nun/ day t? 25 gpm/sq f l and
ft TDH
Methanol addition
Type of Energy Required: Elcitric.il
54
-------
Figure
Number
From EPA
430/9-77-011
Operation, Process, and Equation Describing
Energy Requirements
Design Conditions, Assumptions and
Effluent Quality
3-41 Denitrification - Fixed Film, Upflow
(Based on Experimental Data)
log Y = 4.4935 + 0.8695 (log X) + 0.0864 (log X) ^
- 0.0012 (log X)3
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
3-44
Water Quality: Influent Effluent
(mg/1) (mg/1)
Nitrate as N 25 0.5
Design Assumptions:
Sand media size = 0.6 mm
Fluidized depth = 12 ft
Influent pumping TDH = 20 ft
Temperature = 15°C
Operating Parameters:
Methanol addition = 3:1 (CH3OH:N03-N)
Type of Energy Required: Electrical
3-42 Single Stage Carbonaceous, Nitrification, and
Y =
Denitrification Without Methanol Addition,
Pulsed Air
0 95
391,000 X '"
Water Quality:
BOD5
TKN
Temperature
Influent
(mg/1)
210
30
15°C
Effluent
(mg/1)
20
/.5
-
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Operating Parameters:
Oxygen supply for nitrif ication/denitnf ira-
tion =1.2 BOD5 removed +4.2 (TKN
removed) - 4.6 (0.6 TKN applied)*
Mechanical aeration
Denitrification mixing = 0.5 hp/1000 LU ft
Detention time = 12 hours
Includes final sedimentation @ 300 gpd/sqft
and 50% sludge recycle
Type of Energy Required: Electrical
*Reference: Bishop, D.F., et al., WPCF
Journal, p. 520 (1976)
3-43
Separate Stage Carbonaceous, Nitrification and
Denitrification Without Methanol Addition
(Based on Experimental Data)
n QH
v _ /.ii nnn v • °
Water Quality:
BODj
NH3-N
Influent
(mg/1)
210
30
Effluent
(mg/1)
20
7.5
Electrical Energy Required, kwh/yr
Plant Capaci ty, mgd
Single Stage Carbonaceous, Nitrification, and
Denitrification Without Methanol Addition -
Orbital Plants* (Based on Experimental Data)
Y = 436,000 X°'99
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Operating Parameters:
Air supply for nitrification = 1.1 Ib
02/lb BOD removed + 4.6 Ib 02/lb NH^-N
removed
Mechanical aeration, 1.8 Ib 02
transferred/hp-hr
Denitrification mixing = 0.5 hp/1000 < u it;
3 hr detention
Final aeration stage = 1 hr detent ion;
1 hp/1000 cu ft
Sedimentation @ 700 gpd/sq ft; 30% recycle
Type of Energy Required: Electrical
Water Quality : Influent
(mg/1)
BOD 210
NH3-N 30
Temperature 15°C
Operating Parameters:
Total aeration ditch detention tim
F/M ratio = 0. 16
Rotor aeration
Sedimentation @ 700 gpd/sq it; 50,"' r<>< y<
Type of Energy Required • Elet tr i' a I
*Ref erent e : Natsche , N.I. and Sp.it /i IT LT ,
Austrian Plant Knocks Out Nitrogen, W.iU r
Wastes Engr., p. 18 (Ian, 1975)
3-45 Lime Feeding
Y
Y
Y
Y
Y
X
= 6,700 X°'75 Slaked lime, low lime
0 75
•= 11,000 X Slaked lime, high lime
- 7,600 X°'81 Quicklime, low lime
0 81
- 13,300 X ' Quicklime, high lime
= Electrical Energy Required, kwh/yr
= Plant Capacity, mgd
Design Assumptions:
Slaked lime used for
plants
0.1-5 mgd L ,i|i.u 1 1 v
Quicklime used for 5-100 mgd c.ip.u i ty pl.im
Operating Parameters:
300 mg/1, Lou LimL1 as
600 mg/1, High Linit' a
Type of Energy Required
C,i(OH)2
s C,,(OH)2
: Elei trii.il
55
-------
Figure
Number
From EPA
430/9-77-011
Operation, Process, and Equation Describing
Energy Requirements
Design Conditions, Assumptions and
Effluent Quality
3-46 Alum Feeding
log Y = 3.4969 + 0.2487 (log X) + 0.2711 (log
+ 0.1337 (log X)3
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Operating Parameters:
Dosage - 150 mg/1 as A12(S04)3 - 14H,0
Type of Energy Required: Electrical
3-47 Ferric Chloride Feeding
log Y = 3.4586 + 0.3358 (log X) + 0.2082 (log
•f 0.0053 (log X)3
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
X)
Operating Parameter:
Dosage - 85 mg/1 as FeCl3
Type of Energy Required: Electrical
3-48 Sulfuric Acid Feeding
log Y = 3.1523 + 0.0204 (log X) + 0.0270 (log X)2
+ 0.0188 (log X)3
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
3-49 Solids Contact Clarification - High Lime, Two
Stage Recarbonation (Includes reactor
clarifier, high lime feeding, sludge
pumping, two stage recarbonation)
log Y = 5.1077 + 0.8739 (log X) + 0.1084 (log X)2
- 0.0549 (log X)3 - Liquid C02
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Operating Parameter:
Dosage = 450 mg/1 (high lime system)
Dosage = 225 rag/1 (low lime system)
Type of Energy Required: Electrical
This curve is valid for chemical treatment
of both raw sewage and primary effluent.
Water Quality: Influent Effluent
(Treatment of Raw Sewage) (mg/1) (mg/I)
Suspended Solids 250 10
Phosphate as P 11.0 1.0
Water Quality: Influent Effluent
(Treatment of Pri. Eff.) (mg/1) (mg/1)
Suspended Solids 80 10.0
Phosphate as P 11.0 1.0
Design Assumptions and Operating Parameters
are shown on the following curves in
EPA 430/9-77-011. Lime Feeding, Figure
3-45; Reactor Clarifier, 3-53; Sludge Pump-
ing, 3-4; Recarbonation, 3-60,
3-61; Recarbonation Clarifier, 3-15
Type of Energy Required: Electrical
3-50 Solids Contact Clarification, High Lime,
Sulfuric Acid Neutralization (Includes
reactor clarifier, high lime feed,
chemical sludge pumping, sulfuric acid
feed)
log Y = 4.5932 + 0.6333 (log X) + 0.2024 (log X)2
0.0208 (log X)3
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Solids Contact Clarification Single Stage Low
Lime With- Sulfuric Acid Neutralization
(Includes reactor clarifier, low lime
feeding , sludge pumping , sulfuric acid
feeding)
log Y = 4.5447
0.6844 (log X) + 0.1365 (log X)
3
- 0.0461 (log X)
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
This curve is valid for chemical treatment of
both primary and secondary effluents
Water Quality: Influent Effluent
(Treatment of Raw Sewage) (mg/1) (mg/1)
Suspended Solids 250 10
Phosphate as P 11.0 1.0
Water Quality: Influent Effluent
(Treatment of Sec. Eff.) (mg/1) (mg/1)
Suspended Solids 30 10
Phosphate as P 11.0 1.0
Design Assumptions and Operating Parame ters
are shown on the following curves in EPA
430/9-77-011:
Lime Feeding, Figure 3-45; Reac tor
Clarifier, 3-53; Sludge Pumping, 3-4;
SulfuriL. Acid Feeding, 3-48
Type of Energy Required: Electrical
This curve is valid for chemical treatment of
both raw sewage and primary effluents
Water Quality: Influent
(Treatment of Raw Sewage) (mg/1)
Suspended Solids 250
Phosphate as P 11.0
Water Quality: Influent
{Treatment of Pri. Eff.) (mg/1)
Suspended Solids 30
Phosphate as P 11.0
Design Assumptions and Operating Par.imt-'t ers
are shown on the following curves in I'.PA
430/9-77-011:
Lime Feeding, Figure 3-45; Realtor
Clarifier, 3-53; Sludge Pumping, 1-4;
Sulfuric Acid Feeding, 3-48
Type of Energy Reqm red: Electric ,i 1
56
-------
Figure
Number
From EPA
430/9-77-011
Operation
Process, and Equation Describing
Energy Requirements
Design Condit ions , Assumptions md
Effluent Quality
3-52 Solids Contact Clarification, Alum or Ferric
Chloride Addition (Includes chemical
feeding, reactor clarifier, sludge
pumping)
log Y = 4.6237 + 0.6983 (log X) + 0.1477 (log X)2
- 0.0470 (log X)3 - Alum
log Y = 4.5496 + 0.6894 (log X) + 0.1645 (log X)2
- 0.0559 (log X)3 - Ferric Chloride
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
3-53
This curve is valid for chemical trea rment i*-'
both raw sewage and primary ef fluent)
Water Quality: Influent lift 1 uent
(Treatment of Raw Sewage) (mg/1) (mg/l)
Suspended Solids 250 30
Phosphate as P 11.0 1.0
Water Quality: Influent Kfllucnt
(Treatment of Pri. Effl.) (mg/1) (mg/1)
Suspended Solids 80 10
Phosphate as P 11.0 1.0
Design Assumpt ions and Operating Parameters
are shown on the following curves In EPA
430/9-77-011:
Alum or Ferric Chloride Feeding, Figure
3-46, 3-47; Reactor Clarifier, 3-5 ';
Sludge Pumping, 3-5 , 3-6
Type of Energy Required : Electrical
Reactor Clarifier
log Y = 4.3817 + 0.7223 (log X) + 0.0947 (log X)2
- 0.0027 (log X)3
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Operating Parameters:
Separation zone overflow rate , 1 ime
1400 gpd/sq ft
Separation zone overf low rate , alum
ferric chloride = 1000 gpd/sq ft
Type of Energy Required: Electrical
3-54 Separate Rapid Mixing, Flocculation, Sedimentation
High Lime, Two Stage Recarbonation
log Y = 5.0961 + 0.9484 (log X) + 0.1979 (log X)2
- 0,0101 (log X)3 - Liquid C02
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
This curve is valid for chemical tre
both raw sewage and secondary effl
Water Quality: Influent
(Treatment of Raw Sewage) (mg/1)
Suspended Solids 250
Phosphate as P 11.0
Water Quality: Influent
(Treatment of Sec. Eff.) (mg/1)
Suspended Solids 30
Phosphate as P 11.0
Design Assumpt ions and Operating Par
are shown on the following curves
430/9-77-011:
Lime Feeding, Figure 3-45; Rapid
3-58; Flocculation, 3-59; Sedime
3-15; Recarbonation, 3-60, J-6 1 ;
Pumping , 3-4
Type of Energy Required: Electric, a 1
at ment
lie nt
Ft 1 IIIL-
(rng/U
10
1.0
EI n
(mg/1)
10.0
1.0
iimet ers
in EPA
nt
IC
Mixing,
ntation,
Sludge-
Separate Rapid Mixing, Flocculation, Sedi-
mentation Single Stage High Lime,
Neutralization With Sulfuric Acid
log Y = 4.5919 + 0.6683 (log X) + 0.1926 (log X)'
- 0.0432 (log X)3
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
This curve is valid for chemical t re.it ment
both raw sewage and secondary eftlu
Eff.)
Influent litt ) uem
(mg/1) (mp/1)
250 10
11.0 1.0
Influent Cl f lliL'nt
(mg/1) (mg/1)
30 10
11.0 1.0
Design Assumptions and Operating P.ir.imelers
are shown on the following curves m 1 PA
430/9-77-011:
Lime Feeding, Figure 3-45; Rapid Mixing,
3-58; Floc-culation, )-59; Sediment 11 inn,
3-15; Sludge Pumping, J-4; Sulturi Vid
Feeding, 3-48
Type of Energy Required. llc-ctru.il
Water Quality:
(Treatment of Raw Sewage)
Suspended Solids
Phosphate as P
Water Quality:
(Treatment of Se
Suspended Solids
Phosphate as P
57
-------
Figure
Number
From EPA
430/9-77-011
Operation, Process, and Equation Describing
Energy Requirements
Design Conditions, Assumptions and
Effluent Quality
3-62
Microscreens
Y = 65,000 X°"79 23y Screen
Y = 42,700 X
.0.79
35p Screen
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Water Quality: Influent Effluent
(mg/1) Cmg/1)
Suspended Solids (35y) 20 10
Suspended Solids (23u) 20 5
Design Assumptions:
Loading rate (35y) = 10.0 gpm/sq ft
Loading rate (23p) = 6.7 gpm/sq ft
Operating Parameters:
80% submergence
Type of Energy Required: Electrical
Equation for 35jj screen applicable above 0.2
mgd. For flow rates <0.2 mgd energy
requirements = 11,000 kwh/yr.
Equation for 23jj screen applicable above 0.1
mgd. For flow rates <0.1 mgd energy
requirements = 11,000 kwh/yr.
3-63
Pressure ;
Y = 31 X1
1
and
.01
on
Gravity Filtration
Pressure Filters
Water Quality:
Suspended Solids
Influent
(mg/l)
20
Effluent
(mg/1)
•UO
Y = 22 X " Gravity Filters
Y = Electrical Energy Required, thousand kwh/yr
X = Plant Capacity, mgd
Design Assumptions:
Includes filter supply pumping (or allow-
ance for loss of treatment system head);
filter backwash supply pumping, and
hydraulic surface wash pumping (rotating
arms)
Pump Efficiency: 70%; motor efficiency: 93%
Filter and back wash head: gravity filters,
14 ft, TDH; pressure filters, 20 ft TDH
Surface wash pumping: 20 ft TDH
Filtration rate (both filters): 5 gpm/sq ft
Back wash rate (both filters): 18 gpm/sq ft
Hydraulic surface wash rate (rotating arm)
1 gpm/sq ft (average)
Operating Parameters:
Filter run: 12 hrs. for gravity, 24 hrs.
for pressure
Back wash pumping (both filters) : 15 mm.
per back wash
Surface wash pumping (both filters): 5 nun.
per back wash
Type of Energy Required: Electrical
3-64 Granular Carbon Adsorption - Downflow
Y =
Pressurized Contractor
= 74,000 X1'00
Water Quality:
Suspended Solids
COD x
Inf luent
(mg/l)
20
40
Effluent
(mg/l)
10
15
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Design Assumptions:
8 x 30 mesh carbon, 28 ft carbon depth, 30
mm. contact
Filtration head: 28 ft TDH (carbon depth)
+ 9 ft. TDH, (piping and freeboard)
Filtration pumping: 7 gpm/sq f t. C^ 37 f t.
TDH (average)
Back wash pumping: 18 gpm/sq ft. t3 37 ft.
TDH (average)
Operating Parameters:
Operate to 20 ft. head loss bui Iding
before backwashing
Backwash pumping: 15 mm per backwash
Type of Energy Required : Electr n .11
3-65 Granular Carbon Adsorption - Downflow Gravity
Contactor
Y - 31,000 X1'00
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Water Quality:
Suspended Solids
COD
Design Assumpt ions:
8 x 30 mesh carbon
3.5 gpm/sq ft
30 mm contact (14 ft
Operate to 6 ft headlo
backwashing
Type of Energy Required:
Influent
(mg/l)
20
40
Kf r iucn
(mg/l)
10
IS
arbon depth)
,s bin 1dup be I ore
Electrii .11
58
-------
Figure
Number
From EPA
430/9-77-011
Operation, Process, and Equation Describing
Energy Requirements
Design Conditions, Assumptions and
Ef fluent QO.I 1 ity
3-56 Separate Rapid Mixing, Flocculation»
Sedimentation Low Lime, Neutralization
With Sulfuric Acid
log Y - 4.4521 + 0.7260 (log X) + 0,2292 (log X)l
- 0.0022 (log X)3
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
This curve is valid for chemical treatment
both raw sewage and secondary el fluent
Water Quality:
(Treatment of Raw Sewage..)
Suspended Solids
Phosphate as P
Water Quality
(Treatment of Sec. Eff.)
Suspended Solids
Phosphate as P
Influent
(mg/1)
250
11.0
Influent
(mg/1)
JO
11.0
I t fluent
img/1)
'0
(< f ' 1 ueni
dug/ IJ
10
1.0
Design Assumptions and Operating Parameters
are shown on the following curves in EPA
430/9-77-011:
Rapid Mixing, Figure 3-58; Fl cv -n |,u ion,
3-59; Sedimentation, 3-15; Lime I eedin^ ,
3-45; Sulfuric Acid Feeding, 1-48,
Che mica 1 Sludge Pumping, 3-4
Type of Energy Required; Electrical
3-57 Separate Rapid Mixing, Flocculation,
Sedimentation Alum or Ferric Chloride
Addition
log Y = 4.4096 + 0.6351 (log X) + 0.2349 (log X)
- 0.0169 (log X) - Alum
log Y = 4.3395 + 0.6226 (log X) + 0.2215 (log X)2
- 0.0133 (log X) - Ferric Chloride
Y = Electrical Energy Required, kwh/vr
This curve is valid for chemical tre.itmcnt H
both raw sewage and secondary et fluent
Water Quality: Influent Effluent
(Treatment of Raw Sewage) (mg/1) (mg/1)
Suspended Solids 250 10
Phosphate ,is P
Water Quality:
(Treatment of Sec. Lff.)
Suspended Solids
Phosphate as P
11.0
Influent
(mg/1)
30
11.0
1.0
Lff luenl
(mg/1)
10.0
1.0
Design Assumptions and Operating
are shown on the f ollowing curves in FPA
430/9-77-011:
Alum or Ferric Chloride Feeding, !• igures
3-46 and 3-47; Rapid Mixing, 3-58;
Flocculation, 3-59; Sedimentat ion, i-14,
Sludge Pumping, 3-3 and 3-6
Type of Energy Required: Electric a 1
3-58 Rapid Mixing
Y - 3,900 X1"00
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
3-59 Flocculation
Y = 9,840 X°-98
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Design Assumptions:
Detention time = 30 seconds
G = 600 se^1
Temperature = 15UC
Coagulant: I ime or al urn or f L> rriL
Type of Energy Required: Elect rn a 1
Design Assumptions:
Detention Cime = 30 minutes
G = 110 sec~l
Temperature = 15' C
Coagulant: J ime or alum or ferric
Type of Fnergy Required: Llei_trual
3-60 Recarbonation - Solution Feed of Liquid CO2 Source
Y = 89,000 X1'03 Low lime
Y = 141,000 X1'03 High lime
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Recarbonation - Stack Gas as C02 Source
Y = 50,000 x1'00 Low lime
Y - 170,000 X ' High lime
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Design Assumptions:
Vaporizer = 25 Ih COj/kwh
Injector pumps = 42 gpm/1000 Ih
Operating Parameters:
Low Lime = 3000 ]h CO>/mil gal
High Lime = 4500 Ih CO;/mil gal
Type of Energy Required: K lect r n
Design Assumptinns:
Stack G.is = 10X CO;,
standard Londition
ope-tat ing tempo rat
scrubbing)
Loss to atmosphere =
I n -jet t ion pressure -
Ope rat ing Pa rameiers:
Low Umf = JOOO Ih L
High lime = 0000 Ib
Type of Energy Require
59
-------
Figure
Number Operat ion, Process, and Equation Describing
From EPA Energy Requirements
430/9-77-011
Design Conditions, Assumptions and
Effluent Quality
3-66 Granular Carbon Adsorption - Upflow Expanded Bed
Y = 62,000 X1*00
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Water Quality:
Influent Effluent
(mg/1) (mg/1)
20 20
40 15
Suspended Solids
COD
Design Assumptions:
30 minutes contact
12 x 40 mesh carbon
15% expansion, 7 gpm/sq ft (28 ft t arbon
depth)
3 ft freeboard
Type of Energy Required: Electrical
3-67
Granular Activated Carbon Regeneration
Y = 38,000 X
Y = 10,000 X
Y
Clarified raw wastewater
Electricity
Clarified raw wastewater
Fuel - million Btu/yr
Clarified secondary effluent
Electricity
1,100 X1' Clarified secondary effluent
Fuel - million Btu/yr
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Design Assump tions:
Electricity includes furnace driver, after-
burner, scrubber blowers and carbon
conveyors
Fuel required per ID Carbon regenerated:
Furnace = 3,600 Btu
Steam = 1,600 Btu
Afterburner = 2,400 Btu
Operating Parameters:
Carbon dose: Clarified raw wastewater,
1500 Ib/mil gal
Claritled secondary eftlueot,
400 Ib/mil gal
Type of Energy Required: Elect rii_al and Futj 1
3-68 Ion
Exchange for Ammonia Removal, Gravity Water Quality
and Pressure
Y -
Y =
310.
220.
,000
,000
X1'
1
X
.00
.00
Pressure
Gravity
Suspended Sol ids
NH-j-N
Design Assumptions :
Influent
(mg/1)
5
15
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
150 bed volumes throughput/cycle
6 bed volumes/hr loading rate
Gravity bed, available bead = 7.25 f" t
Pressure bed, ave rage operating head - 10 it
Includes bat kwash but not regene rat ion nor
regenerant renewa1
10% downtime for regeneration
Type of Energy Required: Electric a 1
3-69 Ton Exchange For Ammonia Removal - Regeneration
Y = 2,000 X1'00
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Ion Exchange for Ammonia Removal - Regenerant
Renewal by Air Stripping
Y = 120,000 XL'°° with NH3 recovery
Y - 65,000 X1' without NH3 recovery
Y = Elet trical Energy Required, kwh/yr
X = Plant Capac ity, mgd
Ion Exchange lor Ammon ia Removal, Regenerant
Renewal by Steam Stripping
Y = J.,80 X1-04
Elet t n city
Y = 6,150 X ' Fuel-million Btu/yr
Y = Electrical l-nergy Required, kwh/yr
X - Plant Capacity, mgd
Design Assumptions:
Regeneration with 2% NaCl
40 BV/regeneratioii; 1 regeneration/24 h
Total head - 10 ft
Does not include regenerant renewa 1
Applicable to gravity or pressure beds
Type of Energy Required: Electrical
Design Assumptions:
Regenerant softened wi tli NaOH, clarified at
800 gpd/sq ft
40 BV/regeneration cycle; 150 BV throughput
per Lycle
Regenerant air stripped; tower loaded a t 7(>0
gpd/sq ft with 565 eu ft air/gal
Stripping towe r overal1 height = 12 It
Ammonia recovered in adqnrpt ion t ewer wi t li
H2S04
Type of Energy Required: Electrical
Design Assumptions:
S t e am stripping used
Spent regeneran t softened with soda i^h U
pH = 12
Steam stripper height =• 18 ft
4.5 BV/regeneration tytle, 150 BV
throughput/ion exchange eyele
Power includes sot toning, pH adj usimenl,
pumping to stripping tower
Kuel based on 15 Ib steam required/1 ,000
gal wabt t? water t re at ed
NH-j recovered
Type of Energy Reqm red : F 1 e< t r n ,1 1 am! I IK. i
60
-------
Design Conditions, Assumptions and
Effluent Quality
Ammonia Stripping Water Qua1ity: Influent Effluent
1.01 pH 1! 11
Pumping Air temp., °F 70 70
Fans NH-j-N, mg/1 15 3
De s i gn As s ump 11 o n a :
Pump TDH = 50 ft
1 = E 1 eo t rii. a I Energy Requi red , kwh/yr Operat ing Parameters :
X = Plant (\ipatity, mgd Hydraulic loading = 1.0 gpm/sq ft
Air/Water ratio = 400 cu ft/gal
lype uf Energy Required: Electrical
Breakpoint Ch 1 or mat ion With Dechl orinat ion W iter Quality: influent Eft l^uent
(mg/1) (mg/1)
NH4-N 15 0.1
4- Q.045H (log X) Dec hlorination with Design Assumptions:
At tivated Carbon Dosage ratio, Cl2:NH4-N is 8:1
lo, Y = 5.0593 + 0.2396 (log X) + 0.08M (log X)2 ^sidual Cl? - 3 mg/1 ^
Detention time in rapid mix - 1 ruin.
+ 0.0084 (log X) Dethlorination with Sulfur Dioxide feed ratio, S02:C12 - 1:
Act ivated t arbon pumping, fDH = 10 ft
Type of Energy Required: Electrical
Water Quality: Influent Effluent
BOD5, mg/1 20 20
Suspended Solids, mg/1 20 20
Coliform, no./lOO ml 1000 200
Dechlormat ion Design Assumptions:
Evaporator used for dosages greater rhah
^000 Ih/day
Dechlorination by S02 assuming an :>{]2:l'^2
Dech lorination ratio of 1:1 and SO:>:Cl2 residua ob '*!
, , ,, , . , , No evaporator for SO?
> = f- let t r ic al Energy Required . k- s , yr „ „
Operat-i ng Parameters:
v - Plant Capacity, mgd K^. n b ._
K h Chlorine dosage = 10 mg/L
Chlorine residua 1 - 1 mg/1
Type of Energy Required: KlectricaJ
Design Assumptions :
Chlorine Dioxide dosage is 4 mg/1
(equivalent to 10 mg/] C12J
Sodium Ch lorite : Lh lor me Dioxidt rat 10
Chlotinc-: 'chlorine LHoxlde ratio = I.b8
anl Capacity, mgd
Type Q{ ^^ Required: Electrical
Water Qua'ity: Influent hi 1luent
Suspended Solids, mg/1 10 10
Fecal col i forms/100 ml 10,000 _'00
Oxygen Feed Design As sump tions:
... , , , , Ozone generated from air <) 1.0% wt . <. oncen-
Y =• FlectricaJ Lnergv Required, kwh/yr , ,, „ _„,
h* ^ ' J trat ion and oxygen 3 2.0%
X - Plant Capacity, mgd rt T, JB
Operating Paramoters:
Ozone dose = 5 mg/1
Type of Energy Required: Electrical
Ion Kx< hange for Deminera 1 i zat ion, Cr.ivity and Water Quality: Influent
H = 9o"oOoT'-°° Cravtty , ''DS ^°°
Design Assumptions:
Y - 120,000 -X ' Pressure Loading rate ' gpm/cu ft ,
Gravity bed, available head = 7.25 it
Pressure bed, avt rage oper it i ug In d 10 1 t
Im 1udes backwash but not cegeneration nor
regenerant d isposa1
Type of Eneigy Required: L 1 et triia 1
61
-------
Figure
Number
From EPA
430/9-77-011
Operation, Process, and Equation Describing
Energy Requirements
Design Conditions, Assumptions and
Effluent Quality
,0.95
3-78 Reverse Osmosis
Y - 2,850,000 X1
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Water Quality: Influent Effluent
pH 67
Turbidity, JTU ^-l.Q 0. 1
TDS, rag/I 500-1300 100-200
Design Assumptions:
Feed pressure = 600 psi
Sing]e pass system
Operating Parameters:
Water recovery: 0.1-1 ragd 75%
1 - 10 mgd 80%
10 - 100 mgd 85%
Type of Energy Required: Electrical
3-79 Land Treatment by Spray Irrigation (Modified)
1 on
Y = 270,000 X Center Pivot
Y = 164,000 X1'00 Solid Set
Y = Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Design Assumptions:
Irrigation season is 250 days/vr
Center pivot, TDH = 196 ft
Solid set, TDH = 175 ft
Type of Energy Required: Electrical
3-80
Land Treatment by Ridge and Furrow Irrigation
and Flooding (Modified)
Y = 20 X ' Ridge and Furrow Fuel, million
Btu/yr
Y = 16,000 X1'00 Flooding Power
Y = 12,000 X
Ridge and Furrow Power
Y = Electrical Energy Required, kwh/yr except
for fuel
X = Plant Capacity, mgd
3-81 Infiltration/Percolation and Overland Flow by
Flooding (Modified)
V1.00
Y = 9,200 X
Y = 3,000 X
1.02
Overland Flow
Rapid Infiltration
Y * Electrical Energy Required, kwh/yr
X = Plant Capacity, mgd
Design Assumptions:
Irrigation season is 250 days/yr
Power includes runoff return pumping
Fuel for annual leveling and ridge and
furrow replacement
Type of Energy Required: Electrical and
Diesel Fuel
Design Assumptions:
Infiltration/percolation, TDH = 5 ft
Overland flow, TDH = 10 ft
Disposal time is 250 days/yr for Overland
Flow
Disposal time is 365 days for Rapid
Infiltration
Type of Energy Required: Electrical
3-82
Infiltration/Percolation and Overland Flow by
Solid Set Sprinklers (Modified)
1.00
170,000 X
vl-00
Overland Flow
75,000 Xi
-------
Numhi-i
From PA
3U/^ -Oi
3-87
Oper.jtion, Process, and Equation Describing
Energy Requirements
Wast -water Treatment Plant Building Cooling
Requirements
log V -- 4.0520 + 0.5279 (log <) + 0.0356 (log X)'
,3
- 0.0168 (log X)'
Miami
log Y = 2.8103 + 0.5)04 (log X) + 0.1114 (log X)
,3
- 0.0044 (log X)'
Minneapolis
log Y = 2.9050 + 0.iJ26 (log X) t 0.0692 (log X)
- 0.0321) (log X)3 New York
Y = Building Cooling Requirements, kwh/7r
X = Plant Capacity, ragd
Gravity Thickening
Y = 6.72 K0'95 Lime Sludge and Other Sludge for
Thickener md -.2,200 ft"1
Y = 174 X ' Other SJ 'dge from 2,200 to SI.OOO
ft2'of Thickener \rea
Y = 1.70 X " Other Sludge tor Thickener Area
>9,000 ft2
Y = Electrical Energy Required, kwh/hr
X = Thickener Area, sq ft
Air Flotation Thickening
Y- 1,730X°-87
Y = Electrical Energy Required, kwh/yr
X - Surface Area, sq ft
Basket Cen
Y = 1,070
trifuge
X0.72
.00
'•800 fr/da> ot dewatered solids
>800 tr^May of dewatered solids
l = Electr
X = Dewate
ical Energy Required, kwh/yr
red Solids Capat ir v, cu ft/dd
Flutriat ion
Y = 1,660 X°
3,100 X
.0.97
Digested Primary
Digested Primary + Waste
Activated Sludge and Digested
Primary + Waste Activated
Sludges with FeCl3
\ = F, le^t r i cal Energy Required , kwh/yr
X - Sludge truant ity, ton/day Mry solids)
Heat Treatment
Jc.i, - 1.5710 + 0. m8 Oog X) + 0. 1754 (log X)
-l- 0.0914 (log X) Low Oxidation (Air
Addit ion)
log Y = 1. i801 + 0.1952 (log X) + 2.2864 (log X)^
-t- 0. "i I ^ (.log \) Thermal Conditioning
(No Air)
Y = I- li'i. t r K al Energy Requi red , t ho us and kwh/yr
X = The rma 1 Treatment Capa<. i! v , gpm
Design Conditions, Assumptions am1
Effluent Quality
Note; See chapter 5, pages 5-8 to 5-10 in
EPA 430/9-77-011
See Table 3-4 in EPA 430/9-77-011 for design
assumptions and operating parameters.
Lime curve based on tertiary system at bO
Ib/sq ft/day
Type of Energy Required: Eleitrical
See Table i-5 for design assumptions and
operating parameters in EPA 430/9-77-011.
Curve corresponds to a maximum air require-
ment of 0.2 Ib/lb solids and average of 0.3
-,cfm air/sq ft surface area.
Type of Energy Required: Electrical
Design Assumptions:
Operating hp is . 175 times rated hp
See Table 3-6 for specific sludge
characteristics in EPA 430/9-77-011.
Multiple units required above 800 cu ft/day
capacity
Operating Parameters.
Machines run for 20 nun. are off for K nin.
10 min. allowed tor unloading, rest art ing
and at taming running speed.
Type of Energy Required Electrica'
Sludge
1. Digested primary (i> 8% solids
2. Digested primary + W.A.S. i? 4% solids
3. Digested primary + W.A.S. (+ FeCl-j)
& 4£ solids
Design Assumptions :
Overf low rates = 800 gpd/sq ft for 1
!>00 gpd/sq ft for 2 6, 3
Mixing energ\ : (! = 200 'sec~' for 5 mm.
per stage
TDH = 30 ft for sludge and 2S ft f,n watt-
Ope rat ing Paramot ers :
Two - stage, >T inter- urront system with
separate miMiig and settling tankb
Wash water to sludge ratio =4:1
Type of Energy Requi red : Elcv t rical
De s i g n Ass ump 1 1 o n s :
Reactor Conditions - 300 psig al J5
?leat ex- hanger AiT = 50°F
Cont inuous ODCTL! t Lon
See Table lj~9 tor sludge desiriptio
text in Ch,.pU'r 3 in EPA 430/9-77
Curve me 1 udes
Pressur i zat ion :ium()
Sludge grinders
Post-thickener driven
Boi J er feed pi imps
Air L omp re s s o r s
Type of Energy Required : E I e*. t r i ( a i
63
-------
Figure
Number Operation, Process, and Equation Describing Design Conditions, Assumptinns inn
I'rom EPA Energy Requirements Effluent Quality
430/9-/7-011
90 Heat Treatment - Without Air Addition Design Assumptions:
X1*00 Reactor conditions - 300 psig at Jbl)0]-
Heat exchanger " T = 50°F
V = Fuel Required, million Btu/yr Continuous operation
X = Thermal Treatment Capacity, gpm See Table 5-9 for sludge description md
text of Chapter 5 in EPA 410/9-77 >1
Curve me ludes :
Fuel to produce steam necessary t. raise
reactor contents to opera t ing temper it
Type of Energy Required Fuel
Ues i gn As sump t ions :
Primary * W.A.S. RLM'-tOr "ndUlons - JOO pslg at J^'F
Heat exchanger AT - iO°F
W.A.S. Continuous operation
^ Tjb1' f"r udSe d^ripti.n ,ad
Y = 370 X' Priory (+ ^Cl,) + W.A.S. and j'; "
Primal t W.A.S. (+FeCl,l text of Ch"''ter 5
nn " J Curve LUC ludes:
Y = 420 X " Tertiary Alum Fuel to protlm e steam nei essarv t<> raise
„ „ , n , ,, n. / reactor contents to operating temperature
Y = ?uol Required, million Btii/vr _ r _ ' t> i
v rp, , T, ^. ' T>'Pe of Energy Required: 1-uel
K = Thermal Treatment (,ap,u ity, gpm hj '
Heat Treatment - With Air Addition Design Assumptions,:
,1.00 ,, Reactor .conditions - 300 psig at •lr>0°F
\ _ Prlmary Heat exchange, AT = 50°F
Y = 310 X1 'W1J Dig. Primary Continuous ope rat ion
,,„ V1.00 ,. ,, , , See Tdh V 5-9 for sludge description and
\ = 360 X Dig. Primary + W.A.b. and _ _ fo '
Primary 4 W.A.S. (+PeCl J1
, „ J Curve intludes•
Y = 400 X ' ^S- Primary -i- W.A. i. (-t-S-eClj) Fue 1 to produc <_ st earn nee essary t; ra i.se
.. ,- i n j 'i n / rea "tor cont entb t.) opera ti ng tt mperat u
Y = f-uel Required, million Btu/vr _ . , , %,
v ™ , ,, ,, ' Type of hnergy Required: Fuel
X = Thermal treatment Capacity, gpm ' bJ '
Chemical Addition (Digested Sludges) Design Assumptions
log Y = 3.6422 + 0,3834 (log X) + 0.2290 (log X)' See Table 3-8 pre^dmg Figure S-% lor
^ H chemical quantities in FJ'A 4SO/9-7/-01
Digested Dnmarv Pumping head = 10 ft TDJ'
Curves im lude:
Chemical feeding and Handling
0.1037 (log V^ ' Digested Primary + Waste Sludge pumping
A> L ivated and Digested S 1 udge-chemii. a 1 mi King
Primary + Wa^te Type of Fnergy Required: ElecrrLf.il
Ac t ivated with KeCl .,
he in i' a 1 Add i I ion (I'm! i gested SI udges ) Des ign Assumpt ion-.:
og Y - i.3641 + O.J108 (Ing X) + O.'rtA (log X)2 , Jvc'^Im'hide •= '" '' TU"
Waste At i ivated Chemical feeding and handling
S1udge pumping
M udge-( hemic a I mixing
Type nt Knorgy Requ ired : E let ! >" i i al
sol ids l
Vacuum Filtration See Table 1-7 tor design assumptions in l< \>'
log Y - y4.P.'+rj •+ 0.0840 (1,,^ X) • O.'lHh (lor <) . l30/9-/7-()l1
Ope rat ing Paramet er.s'
- 0.0177 ( log M 2 sc fm/sq i t
I i LLrate pump, iO t ' mil
Curve i in 1 udcs . drum dr i\ c , J i i !i.i rge
rol [LT , vat ai-1 i a I or, \-at 'inn pump,
i i I t r 111. puni|
i vpe o I File t gy Requ t r- ti F i et l r 11 a 1
64
-------
Figure
Number
From EPA
U30/9-77-011
Operation, Process, and Equation Describing
Energy Requirements
Design Conditions, Assumptions and
Effluent Quality
3-96
Filter Pressing
.0.58
Influent solids =
7,810 X°'6° Influent solids
Y = 6,980 X
Y =
Y = 6,710 X°'71 Influent solids = 4%
Y = Electrical Energy Required, kwh/yr
X = Filter Press Volume, cu ft
See Table 3-8 for design assumptions in EPA
430/9-77-011
Operating Parameters:
Power consumption based on continuous
operation, 225 psi operating pressure
Curve includes:
Peed Pump (hydraulically driven, positive
displacement piston pump)
Opening and closing mechanism
Type of Energy Required: Electrical
Centrif uging
Y = 4,000 X '
1 02
Y = 1,940 X '
Lime sludge classification
Dewatering
Operating Conditions:
Power consumption based on continuous
operation
Dewatering accomplished with low speed
centrifuge, G = 700 sec"
X = Flow, gpm Sludge Type
Primary + Low Lime
Tertiary + Low Lime
Primary + 2 Stage High
Tertiary + 2 Stage High
Type of Energy Required
Conditions
No <.lnssi f Ic at LOU
No class if icat ion
Lime Classification
followed by
dewatering
Lime Classif K ation
followed by
dewater ing
: Electrical
Y = 4.0 X
2.1 X
1.02
3-98 Sand Drying Beds
log Y = 2.1785 +0.9543(log X) + 0.0285 (log X)'
+ 0.0020 (log X) Power Consumption
1 0?
Fuel Consumption @ 7.5% solids
pumped, million Btu/yr
Fuel Consumption @ 5.0% solids
pumped, mil lion Btu/yr
Fuel Consumption @ 2.5% solids
pumped, million Btu/yr
" Fuel Consumption @ 1.0% solids
pumped, million Btu/yr
Y = Fuel Required, million Btu/yr except Power
Consumption Which is kwh/yr
X = Sludge Quantity, gpm
Y - 1.2 X
Y = 0.42 X
1.00
Design Assumptions:
Power consumption based on pumping to
drying beds at TDK = 15 ft
Fue1 consumption based on:
drying to 50% solids, 70 Ibs/cu ft
loading with front end loader, 8 gal/hr
use of diesel fuel (140,000 Btu/gal)
15 minutes required to load 30 cu yd t ruik
See Table 3-3 for quantities of various
sludges/mil gal treated in EPA 430/9-77-011
Type of Energy Required: Electrical and
Fuel
3-99 Sludge Pumping
log Y = 2.6558 + 1.4926 (log X) - 0.2455 (log X)2
+ 0.0065 (log X)3
Y = Electrical Energy Required, kwh/yr per mile
X = Annual Sludge Volume, mil gal
3-100
Dewatered Sludge Haul by Truck
"-"'""" Truck Capacity
Y - 4.6 X
Y ^ 2.6 X
1.00
1.00
10 yd
Truck Capacity = 15 yd
Truck Capacity = 30 yd
Y = Fuel Required, mil I ion Btu/one way mile/yr
X = Annual Sludge- Volume, 1,000 cu yd
Design Assumptions:
4% solids maximum (Dilute to 4% if
4 inch pipelme minimum, design ve
3 fps
Pipeline effective "c" factor 85
Pumping based on centrifugal non-i
slurry pumps, 68/£ efficient y
20 hours per day average operat jon
Operat ing Parameters:
See Table 3-9 for sludge rhar,K te r
for disposal in KPA 4 JO/9-77-011
Type of Energy Required: Electrical
lot uy
Design Assumptions:
1 gal diesel (#2) = U0,000 Btu
Diesel powe red dump t ru< ks
OperaL ing Pararnete rs :
Operation 8 hr per day
Aver?i*e speed; 25 mph lor first
and 35 mph there,) I te-
Truck fuel use 4.5 mpg ivg
See Table J-9 for sludge rharn
for disposal in KPA 410/9-77-
Typt> of Energy Required: '•'2 Dies
65
-------
Figure
Number
From EPA
430/9-77-011
Operation, Process, and Equation Describing,'
Energy Requirements
Design Conditions, Assumptions and
Effluent Quality
3-101
Liquid Sludge Hauling by Barge
5.6 X
11.0
0.97
,,0.97
2 MG
1 MG
Y - 12.0 X
Y - 14.7
.0.97
,,0.97
26.9 X
Barge Capacity
Barge Capacity
Barge Capacity = 0.85 MG
Barge Capacity = 0.5 MG
Barge Capacity » 0.3 MG
Y = Fuel Required, million Btu/one way mile/yr
X = Annual Sludge Volume, 1,000 cu yd
Design Assumptions:
1 gal marine diesel = 140,000 Btu
Non-propelled barges moved with tugs
Operating Parameters:
Operation 24 hrs per day
Average speed 4 mph
Tug size: 300,000 gal barge- 1,200 hp
500,0006,850,000 gal barge -
2,000 hp
1,000,00052,000,000 gal barge -
2,500 hp
See Table 3-9 for sludge characteristics
for disposal in EPA 430/9-77-011
Type of Energy Required: Marine diesel fuel
Liquid Sludge Hauling by Truck
Y = 14.9 X°'98 Truck Capacity = 5,500 gallons
3-102
,,1.01
Y = 25.3 X1'01 Truck Capacity = 2,500 gallons
.2 X1'02 Truck Capacity - 1,200 gallons
= 53.2 X Truck Capacity - 1,200 gallons
= Fuel Required, million Btu/one way mile/yr
= Annual Sludge Volume, mil gal
Design Assumptions:
1 gal diesel (//2) = 140,000 Btu
Diesel powered tank trucks
Operating Parameters:
Operating 8 hrs per day
Average speed; 25 mph for first 20 miles
and 35 mph thereafter
Truck fuel use 4.5 mpg avg
See Table 3-9 for sludge characteristics
for disposal in EPA 430/9-77-011
Type of Energy Required: //2 Diesel fuel
3-103
Utilization of Liquid Sludge
Y
180 X1'00 Land spreading
Y = Fuel Required, million Btu/yr
X = Annual Sludge Volume, mil gal
Design Assumptions:
Fuel use: spreading truck - 2 gal/trip
1 gal diesel (#2) = 140,000
Operating Parameters:
1600 gal big wheel type spreader, 15
minute round trip. Truck is self loading
See Table 3-9 for sludge characteristics
for disposal in EPA 430/9-77-011
Type of Energy Required: //2 Diesel fuel
Utilization of Dewatered Sludge
Y
,,1.00
71 X
Land Spreading
Y = Fuel Required, million Btu/yr
X = Annual Sludge Volume, 1,000 cu yd
Design Assumptions:
Fuel use: Bulldozer - 8 gal/hr
Front end loader - 8 gal/hr
Spreading truck - 3 g.il/trip
1 gal diesel (112) = 140,000 Btu
Operating Parameter:
Landfill: 30 minutes bulldozer time per
cu yd truckload of sludge
Spreading: 7.2 c\s yd big wheel type
spreader, 20 minute trip time
See Table 3-9 for sludge characteristics
for disposal in EPA 430/9-77-011
Type of Energy Required: //2 Diesel fuel
3-105 Mixing - Anaerobic Digester - High Rate
Y = 1.8 X1'00 Mechanical Mixing- 1/4 HP/1000 ft3
3.3 X
1.00
,,1.00
Mechanical Mixing- 1/2 HP/1000 ft
Mechanical Mixing- 1 HP/1000 ft5
log Y = 3.8094 + 0.1464 (lo;
+ 0.0209 (lo|
X) - 0.0721 (log X)
X)3 GasMixing - 5 scfm/lOOOft3
log Y =12.6028 - 6.3342 (log X) + 1.5075 (log X)
- 0.1036 (log X)3 Gas Mixing- 10 scfm/lOOOft3
Design Assumptions:
Continuous operation
20 ft submergence for release
Motor efficiency varies from
depending on motor size
Type of Energy Required: Meet
See Chapter "), pages 5-H to 5-
3-106 for fuel requirements i
430/9-77-OM
log Y = 6.3722 - 1.9562 (log X)
- 0.0301 (lo;
0.5249 (log X)
X)3 Gas Mixing-20 scfm/1000 fl3
Y - Electrical Energy Required, kwh/yr
X = Digester Volume, cu ft
66
-------
Figure
Number
From EPA
430/9-77-011
Operation, Process, and Equation Describing
Energy Requirements
Design Conditions, Assumptions and
Effluent Quality
3-106 Thermophilic Anaerobic Digestion
" ' Primary + High Lime Slud
Y = 0.7 X
Y . 0.8 X
Y = 0.9 X
1.00
1.00
Y = 1.03 X
Y = 1.19 X1
1.01
Primary + (W.A.S. + FeCl3)
Primary + FeCl3, Primary + W.A.S.
and (Primary + Fed ) + W.A.S.
Primary, and Primary + Low Lime
Waste Activated Sludge
Y = Fuel Required, million Btu/yr
X = Solids, Ib/day
Design Assumptions:
Fuel requirements are shown for northern
states, for central locations multiply by
0.5 for southern locations multiply by O.J
Operating Parameter:
Digester temperature 103°F
See Figure 3-105 for mixing energy in KPA
430/9-77-011
See Table 3-3 for sludge characteristics in
EPA 430/9-77-011
Type of Energy Required: Fuel or Natural Gas
Aerobic Digestion
Mec
Time = 8 days
Mechanical Aer
Time = 16 days
Mechanical Aera
Time * 24 days
Diffused
= 8 days
Diffused
= 16 days
Y = 400 X ' Diffused Air - Detention Time
= 24 days
Y = Electrical Energy Required, kwh/yr
X = BODIN - Ib/day
Y = 157 X " Mechanical Aeration - Detention
Y = 200 X1"00 Mechanical Aeration - Detention
Y = 230 X * Mechanical Aeration - Detention
Y = 300 X1'00 Diffused Air - Detention Time
Y = 360 X1'00 Diffused Air - Detention Time
Thermophilic Aerobic Digestion
Y
1'02
125 X1'00 200 Ib BOD / 1000 ft3/day
157 X
100 Ib BOD / 1000 ft/day
Y = Electrical Energy Required, kwh/yr
X = BODIN - Ib/day
Design Assumptions:
Energy based on oxygen supply requirements;
mixing assumed to be satisfied
Mechanical aeration based on 1.5 Ib 02
transfer/hp-hr
Diffused aeration based on 0.9 Ib 02
transfer/hp-hr
Temperature of waste = 20°C
Oxygen for nitrification is not included in
values presented - for nitrification 02
demand + BOD demand multiply value from
curve by 1.3
Type of Energy Required: Electrical
Design Assumptions:
Process is autothermophilie
Pure oxygen provided for oxygen t. ransfer
having the following power demands:
1.5 hp/1,000 cu ft mixing
2.9 Ib 02/hp-hr PSA generation
4.2 Ib 02/hp-hr Cryogenic generation
Cryogenic systems assumed for greater
demands than 5 ton/day
Type of Energy Required: Electrical
Chlorine Stabilization of Sludge
Y- 2.190X0'96
Y = Electrical Energy Required, kwh/yr
X = Sludge Flow, gpm
Design Assumptions:
Operating pressure = 35 psi
Recirculation ratio =5:1
Chlorine feed = 4 lbs/1,000 gal
Type of Energy Required: Electrical
Lime Stabilization of Sludges
Y = 7.50 X ' Lime Dosage » 200 Ib/ton as
Ca(OH)
°'7°
Y = 12.25 X' Lime Dosage = 400 Ib/ton as
Ca(OH)
°'70
Y = 17.97 X' Lime Dosage = 800 Ib/ton as
Ca(OH)2
Y = 30.71 X°'68 Lime Dosage = 1,000 Ib/ton as
Ca(OH)2
Y = Electrical Energy Required, kwh/yr
X = Sludge Quantity, Ib dry solids/day
Multiple Hearth Furnace Incineration (See
Figure 3-112 in EPA 430/9-77-011 for
Start-up Fuel)
Primary Sludge
Primary + Low Lime Sludge
Digested Pnmaiy Sludge
Primary + (W.A.S. + FcClj)
(Primary+ FeClj) +W.A.S.,
(Primary + FeClj)+W.A.S.,
W.A.S.
Primary + FeGl, and W.A.S.-
Y = Fuel Required, million Btu/yr
X = Dry Sludge Feed, Ih/hr
67
Y = 22.30 X
Y = 40.00 X1
Y = 60.00 X
Design Assumptions:
Pumped feed of slaked lime
Mix lime and sludge for 60 seconds at
G •= 600 sec~!
Sludge pumping not included (see Figure 3-4
in EPA 430/9-77-011 if pumping required)
Type of Energy Required: Electrical
Sludge
and
See Table 3-10 for design assumpt
430/9-77-011
Operating Parameters:
Incoming sludge temperature is
Combustion temperature is 1400 !
Downtown for cool-down equals s
Frequency of -Start-ups is a f u
individual systems
Excess air is 1007
Type of Energy Required:. Fuel Oi
Gas
-------
Figure
Number Operation, Process, and Equation Describing
From EPA Energy Requirements
430/9-77-011
Design Conditions, Assumptions and
Effluent Quality
3-112 Multiple Hearth Furnace Incineration Start-Up
Fuel
Y = 0.00194 X
Y = Fuel Required, million Btu/hr
X = Effective Hearth Area, sq ft
Design Assumptions:
Use in conjunction with Figure 3-H1 in KPA
430/9-77-011 to determine total fuel
required.
Heatup time: Effective Hearth Heatup
Area Time
sq__f_t _JlL_
less than 400~ 18
400-800 27
800-1400 36
1400-2000 54
greater than 2000 108
Operating Assumptions:
Heatup time to reach 1400°F temperature
Frequency of start-up LS a function of
individual system
Type of Energy Required: Fuel Oil or Natural
Gas
3-113 Multiple Hearth Furnace Incineration
0 74
Y = 3870 X
Y = Electrical Energy Required, kwh/yr
X = Effective Hearth Area, sq ft
Design Assumptions:
Solids
Concentration, %
14-17
18-22
23-30
31
Loading Rates, Ib/hr/sq ft
(wet sludge)
Small Large
Plants Plants
25 mgd 25 mgd
6.0 10.0
6.5 11.0
7.0 12.0
8.0 12.0
Operating Parameter:
System operates 100% of the time.
3-114 Fluidized Bed Furnace Incineration
Y •= 10.3 X
1'00 Primary Sludge, Rate- 14 Ib/ft2/hr
Y = 12.5 X
1.00
,,1.01
Primary + Low Lime Sludge,
Rate - 18 Ib/ft2/hr
Y * 15.6 X1'01 Digested Primary Sludge,
Rate - 14 Ib/ft2/hr
1 Primary + (W.A.S. + FeCl3),
Y - 31.0 X
rmary ... e
Rate - 8.4 Ib/ft2/hr
Y = 45.0 X1'00 Primary + W.A.S., (Primary +
Fed ) +W.A.S., and W.A.S.,
Rate - 6.8 Ib/ft2/hr
Y - 51.0 X ' Primary + FeCl3 and W.A.S. + FeCl3
Rate - 6.8 Ib/ft2/hr
Y = Fuel Required, million Btu/yr
X = Dry Sludge Feed, Ib/hr
Design Assumptions:
Heat value of volatile solids is 10,000
Btu/lb
See Table 3-10 preceding Figure 3-111 for
more design assumptions in EPA 430/9-77-
011.
Operating Conditions:
Combustion temperature is 1400°F
Downtime is a function of individu.il system
40% excess air, no preheater
Startup not included, 73,000 Btu/sq ft for
startup
Type of Energy Required: Fuel Oil or Natural
Gas
Fluidized Bed Furnace Incineration
0 93
Y = 47,400 X
Y = Electrical Energy Required, kwh/yr
X = Bed Area, sq ft
Sludge Drying
Y = 10 X1'0 Fuel 30% Input Solids Concentration,
million Btu/yr
Y = 16.5 X1'0 Fuel 20% Input Solids Concentration,
million Btu/yr
Y = 200 X1'0 Electricity 30% Input Solids
Concentration
Y = 234 X1'02 Electricity 20% Input Solids
Concentration
Y = 32.4 X Fuel 8% Input Solids Concentration,
million Btu/yr
Y = 277 X1'01 Electricity 8% Input Solids
Concentration
Y = 71.0 X1'01 Fuel 4% Input Solids Concentration,
million Btu/yr
Y - 1154 X1'02 Electricity 4% Input Solids
Concent rat ion
See Table 3-10 preceding Figure 3-111 for
design assumptions in EPA 430/9-77-011
Operating Parameters:
Full time operation
Type of Energy Required: Electrical
Design Assumptions:
Continuous operation
Dryer Efficiency 72%
Product moisture content 10%
Power includes blowers, fans, conveyors
Type of Energy Required, Fuel and FJoctrn
68
-------
Figure
Number
From EPA
430/9-77-011
Operation, Process, and Equation Describing
Energy Requirements
Design Conditions, Assumptions and
Effluent Quality
3-116 Y
(Continued)
2650 X
1.00
Input Solids Concentration,
million Btu/yr
Electricity 2% Input Solids
Concentration
300 X1"00 Fuel 1% Input Solids Concentration,
Y = 5100 X
Y =
1.00
million Btu/yr
Electricity 1% Input Solids
Concentration
Electrical Energy Required, kwh/yr except
fuel required
X = Annual Dry Solids Product, ton/yr
3-117 Wet Air Oxidation
log Y = 2.2518 + 0.6392 (log X) + 0.1259 (log X)^
- 0.0108 (log X)3 Primary + W.A.S.
log Y = 2.1561 + 0.5493 (log X) + 0.1772 (log X)2
- 0.0205 (log X)3 W.A.S.
Y = Electricity Required, thousands kwh/yr
X = Treatment Capacity, gpm
Design Assumptions:
Reactor pressure
Primary + W.A.S. = 1700 psig
W.A.S. = 1800 psig
Continuous operation
See Table 5-9 for sludge description and
text in Chapter 5 in EPA 430/9-77-011
Curve Includes:
Pressurization pumps Boiler feed pumps
Sludge grinders Air compressors
Decant tank drives
Type of Energy Required: Electrical
Note: Fuel is required only at start-up
3-118 Lime
Y =
Y =
Y =
Y -
Y =
X -
Recalcining
051
1544 X '
2094 X°'51
051
2290 X
- Multiple Hearth Furnace
Fuel - Primary, 2 stage high
lime, million Btu/yr
Fuel - Tertiary, low lime,
million Btu/yr
Fuel- Tertiary, 2 stage high
lime, million Btu/yr
18, 650 X°'48 Power, kwh/yr
Electrical Energy Required, .kwh/hr
Hearth Area, sa ft
Design Assumptions:
Continuous operation
Multiple hearth furnace
7 Ibs/sq ft/hr loading rate (wet basis)
Gas outlet temperature = 900°F
Product outlet temperature = 1400°F
Power includes center shaft drive, shaft
cooling fan, burner turboblowers, product
cooler, and induced draft fan
Sludge MefOH) °ther C°m~
Composition: 3 Bv 2 Inerts bustibles
Primary, 2
stage high
lime 657. 27. U7. 20%
Tertiary, low
lime 71 10 16 3
Tertiary, 2 .
stage high
lime 86.1 4.3 6.1 3.5
Type of Energy Required: Fuel and Electrical
4-1 Activated Carbon Secondary Energy Requirements
Y = 1.05 X 400 Ib/mil gal Tertiary granular
Carbon treatment, million Btu/day
Y = 17.5 X1*"00 2,500 Ib/mil gal, IPC Powered
Carbon treatment, million Btu/day
Y = Production Energy, million Btu/day
X = Plant Capacity, mgd
Ammonium Hydroxide Secondary Energy Requirements
1.04
4,175 Ib/mil gal, million Btu/day
Y - 73 X
Y = Production Energy, million Btu/day
X = Plant Capacity, mgd
69
-------
Figure
Number Operation, Process, and Equation Describing Design Conditions, Assumptions and
From EPA Energy Requirements Effluent Quality
430/9-77-011
4-4 Carbon Dioxide Secondary Energy Requirements
Y = 1.5 X1'0 200 mg/1, million Btu/day
Y = 3.2 X1'0 300 mg/1, million Btu/day
Y - Production Energy, million Btu/day
X = Plant Capacity, mgd
4-5 Chlorine Secondary Energy Requirements
Y = 165 Xlp°° 10 mg/1, kwh/day
Y = 1800 X1'00 135 mg/1, kwh/day
Y = Production Energy, kwh/day
X — Plant Capacity, mgd
4-6 Ferric Chloride Secondary Energy Requirements
Y = 200 X1'00 50 mg/1, kwh/day
Y = 700 X1*00 200 mg/1, kwh/day
Y = Production Energy, kwh/day
X = Plant Capacity, mgd
4-7 Lime (Calcium Oxide) Secondary Energy Requirements
Y = 6.2 Xl'° 300 mg/1, million Btu/day
Y = 8.3 X1'0 400 mg/1, million Etu/day
Y = Production Energy, million Btu/day
X = Plant Capacity, mgd
4-8 Methanol Secondary Energy Requirements
Y = 7.9 X1*0 60 mg/1, million Btu/day
Y = Production Energy, million Btu/day
X = Plant Capacity, mgd
4-9 Oxygen Secondary Energy Requirements
Y = 345 X1'0 200 mg/1, kwh/day
Y = Production Energy, kwh/day
X = Plant Capacity, mgd
4-10 Polymer Secondary Energy Requirements
Y = 1950 X ' , 1.4 ///mil. gal., Btu/day
Y = Production Energy, Btu/day
X = Plant Capacity, mgd
4-11 Sodium Chloride Secondary Energy Requirements
Y2= 20 XK° Evaporated, 1200 Ib/mil. gal.
Y,= Production Energy, kwh/day Y2= Production Energy, mil. Btu/day
X = Plant .Capacity, mgd X =Plant Capacity, mgd
4-12 Sodium Hydroxide Secondary Energy Requirements
Y = 550 X1-° 375 Ib/mil. gal., kwh/day
Y = 7100 Xl'° 4760 Ib/mil. gal., kwh/day
Y = Production Energy, kwh/day
X = Plant Capacity, mgd
4-13 Sulfur Dioxide Secondary Energy Requirements
Y = 0.35 X1'0 2 mg/1, kwh/day
Y = Production Energy, kwh/day
X = Plant Capacity, mgd
4-14 Sulfuric Acid Secondary Energy Requirements
Y = 1500 X ' 250 mg/1, million Btu/day
Y = 2600 X1'0 450 mg/1, million Btu/day
Y *= Production Energy, million Btu/day
X = Plant Capacity, mgd
70
-------
Figure
Number Operation, Process, and Equation Describing Design Conditions, Assumptions and
From EPA Energy Requirements Effluent Quality
430/9-77-011
5-1 Estimated Heat Requirements 1000 sq ft Building
Y = 1.7000 + 31.7102 X - 0.7765 X
Case A: Uninsulated
Y = 0.3000 + 17,1750 X - 0.3750 X2
Case B: Added Wall and Ceiling Insulation
With Storm Windows
Y = 0.0491 + 12.3386 X - 0.2538 X2
Case C: Wall and Ceiling Insulation Double
Glazed Windows and Floor Insulation
Y = Heat Required, million Btu/yr
X = Thousand, deg day/yr
5-2 Estimated Floor Area for Wastewater Treatment Plants
,2
log Y = 3.1801 + 0.1789 (log X) + 0.4170 (log X)
,2
- 0.1074 (log X) Total Floor Area
log Y = 2.8073 + 0.4146 (log X) + 0.1857 (log X)
Laboratory and
Administrative Area
- 0.0332 (log X)3 Laboratory and
Y = Floor Area, sq ft
X = Plant Capacity, mgd
Anaerobic Digester Heat Requirements For Primary
Sludge
Y = 3.20 - 0.0290 X South U.S. - Digestion
Temp. - 95°F
Y = 3.43 - 0.0293 X Middle U.S. - Digestion
Temp. - 95°F
Y = 4.03 - 0.0300 X North U.S. - Digestion
Temp. = 95°F
Y = Digester Heat Required, million Btu/mgd
(0.05 Ib VS/day/cu ft)
X = Sludge Temperature to Digester, °F
Anaerobic Digester Heat Requirements for Primary
Plus Waste Activated Sludge
Y - 6.69 - 0.063 X South U.S. - Digester Loading
= 0.05 Ib VS/ft3-day
Y = 7.14 - 0.063 X Middle U.S. - Digester Loading
= 0.05 Ib VS/ft3-day
Y = 8.42 - 0.064 X North U.S. - Digester Loading
= 0.05 Ib VS/ft3-day
Y = 6.11 - 0.062 X South U.S. - Digester Loading
= 0.15 Ib VS/ft3-day
Y - 6.28 - 0.062 X Middle U.S. - Digester Loading
= 0.15 Ib VS/ft3-day
Y = 6.67 - 0.062 X North U.S. - Digester Loading
= 0.15 Ib VS/ft3-day
Y = Digester Heat Required, million Btu/mgd
X = Sludge Temperature to Digester, °F
Heat Requirements Powered Activated Carbon
Regeneration
Y = Fuel Required, million Btu/yr
X = Powered Activated Carbon Regenerated, Ib/day
71
-------
Figure
Number Operation, Process, and Equation Describing Design Conditions, Assumptions and
From EPA Energy Requirements Effluent Quality
430/9-77-011
5-7 Digester Gas Cleaning and Storage Construction Costs
log Y = 0.9701 + 0.8379 (log X) - 0.1235 (log X)2
+ 0.0218 (log X)3 Total Clean Compress and
Store
log Y = 3.1972 - 1.7054 (log X) + 0.6770 (log X)2
- 0.0642 (log X) Clean and Compress
log Y « -0.8547+1.7752 (log X) - 0.3705 (log X)2
+ 0.0521 (log X)3 Store
Y = Construction Cost, thousand dollars
X ~ Digester Gas Cleaned and Compressed, scfm
5-8 Digester Gas Cleaning and Storage 0 &M Labor
Requirements
log Y = 0.2605 + 1.3030 (log X) + 0.0195 (log X)2
- 0.0247 (log X)3
Y = 0 & M Labor, hr/yr
X = Digester Gas Cleaned and Stored, scfm
Digester Gas Cleaning and Storage Maintenance
Material Costs
log Y = -1.6763 + 0.9018 (log X) + 0.2707 (log X)*
- 0.0653 (log X)3
Y = Maintenance Material, thousand dollars/yr
X = Digester Gas Cleaned and Stored, scfm
Digester Gas Cleaning and Storage Energy Requirements
log Y = 1.1149 + 0.4622 (log X) + 0.0753 (log X)2
+ 0.0024 (log X)3
Y = Electricity Required, thousand kwh/yr
X = Digester Gas Cleaned and Stored, scfm
5-11 Internal Combustion Engine Construction Costs 600 rpm engine with heat recovery and
log Y = 5.2829 - 3.6573 (log X) + 1.3169 (log X)2 alternate fuel system
- 0.1250 (log X)3
Y = Construction Cost, thousand dollars
X = 1C Engine, hp
5-12 Internal Cojnbustion Engine 0 & M Labor 600 rpm engine with heat recovery and
Requirements alternate fuel system
log Y = -1.1725 + 1.5611 (log X) - 0.0273 (log X)2
- 0.0146 (log X)3
Y = 0 & M Labor, hr/yr
X = 1C Engine, hp
5-13 Internal" Combustion Engine Maintenance 600 rpm engine with heat recovery and
Material Costs alternate fuel system
log Y = -5.4676 + 4.3514 (log X) - 1.1752 (log X)2
+ 0.1337 (log X)3
Y = Maintenance Material, thousand dollars/yr
X = 1C Engine, hp
5-14 Internal Combustion Engine Alternate Fuel 600 rpm engine with heat recovery and
Requirements alternate fuel system
log Y = -1.9249 + 3.5577 (log X) - 0.7592 (log X)
+ 0.0736 (log X)3
Y = Alternate Fuel Required, million Btu/yr
X = 1C Engine, hp
72
-------
Figure
Number
From EPA
430/9-77-011
Operation, Process, and Equation Describing
Energy Requirements
Design Conditions, Assumptions and
Effluent Quality
5-15 Digester Gas Utilization System Construction
Costs
log Y = 2.5404 - 0.4530 (log X) + 0.6979 (log X)2
- 0.1318 (log X)3
Y = Construction Cost, thousand dollars
X = Plant Capacity, mgd
Complete electricity generation system as
shown in Figure 5-6 EPA 430/9-77-011
5-16 Digester Gas Utilization System O&M Labor
Requirements
log Y = 1.8795 + 1.1374 (log X) - 0.1063 (log X)i
+ 0.0029 (log X)3
Y = 0 & M Labor, hr/yr
X « Plant Capacity, mgd
Complete system for electricity generation
as shown in Figure 5-6 EPA 430/9-77-011
5-17 Digester Gas Utilization System Maintenance
Material Costs
log Y = 4.1712 - 8.2581 (log X) + 6.1717 (log X)2
- 1.3289 (l«g X)3
Y = Maintenance Material, thousand dollars/yr
X = Plant Capacity, mgd
Complete system for electricity generation
as shown in Figure 5-6 EPA 430/9-77-011
Digester Gas Utilization System Energy
Requirements
log Y = 2.4984 + 0.9564 (log X) - 0.0985 (log X)2
Complete system for electrical generation
as shown in Figure 5-6 EPA 430/9-77-011
0.0411 (log
Fuel
log Y = 1.7189 + 0.5938 (log X) - 0.0424 (log X)
+ 0.0068 (log X)3 Electricity
Y = Fue] Required, million Btu/yr
X = Plant Capacity, mgd
5-19 Multiple "Hearth Incineration Construction Cost
log Y = 0.0606 + 0.5432 (log X) + 0.4666 (log X)'
- 0.1592 (log X)3
Y = Construction Cost, million dollars
X = Plant Capacity, mgd
Design and Operation Assumptions:
Loading rate = 6 Ib/sq ft/hr
Sludge: Primary + W.A.S. sludge = 16%
solids
Multiple Hearth Incineration O&M Requirements
Y - 1600 X°-65
Y = O&M Labor, hr/yr
X = Plant Capacity, mgd
Design and Operation Assumptions:
Loading rate = 6 Ib/sc] ft/hr
Sludge: Primary + W.A.S. sludge = 16%
solids
5-21 Multiple Hearth Incineration Maintenance
Material Costs
log Y = 3.5505 + 0.0972 (log X) + 0.3658 (log X)2
- 0.0539 (log X)3
Y = Maintenance Material, dollars/yr
X = Plant Capacity, mgd
5-22 Auxiliary Heat Required to Sustain Combustion
of Sludge
Y = 4.09 - 0,165 X Primary, 60% VS
Y = 4 - 0.179 X Primary+W.A.S., 69% VS
Y = Heat Required, million Btu/ton VS
X = Sludge Solids, % by weight
5-23 Heat Recovered from Incineration of Sludge
Y = -2636.0 + 5.14 X - 0.0002 X2 Primary+ W.A.S.
Y = -1195.4 + 2.06 X - 0.0006 X W.A.S. + Fed,
Y - -820 + 1.71 X
Primary Sludge
Y = Initial Flue Gas Temperature, °F
X = Heat Recovered, million Btu/yr/mgd
5-24
Impact of Excess Air on the Amount of Auxiliary
Fuel for Sludge Incineration
Y = 0.41 + 0.0822 X
Y = Auxiliary Fuel, million Btu/ton dry solids
X = Excess Air, percent
73
Design and Operation Assumptions:
Loading rate = 6 Ib/sq ft/hr
Sludge: Primary + W.A.S. sludge = 167,
solids
Assumptions:
10,000 Btu/lb VS
Assumpt ions:
Final stack temp = 500°F
100% Excess air
See table preceding Figure i-11] for ^
characteristics in EPA 430/9-77-011
Assumptions:
Solids 30%
Exhaust Temp. 1400°F
Volatlles 707,
-------
Figure
Number Operation, Process, and Equation Describing Design Conditions, Assumptions and
From EPA Energy Requirements Effluent Quality
430/9-77-011
5-26 Energy Recovery Rotary Kiln Reactor Pyrolysis
System
Y =• 0.02 X Net Energy Output, Btu/lb input
X - % Refuse _ % Sludge = 100 - X
Y « 0.0 + 0.7150 X - 0.0030 X2
% Recovery of Energy Input
X = 7. Refuse 7. Sludge > 100 - X
5-27 Energy Recovery Vertical Shaft Reactor Pure
Oxygen Pyrolysis System
Y •= 0.09 + 0.0291 Net Energy Output
X = % Refuse % Sludge = 100 - X
Y = 4.8750 + 0.9737X- 0.0041 X2
% Recovery of Energy Input
5-28 Heat Pump Output Based on Wilton Plant Design
Operating Conditions for Various Effluent
Temperatures
Y = -0.0714 + 1.9257 X - 0.0109 X2 •
Output, million Btu/yr/mgd
Y = 0.1529 + 0.0775 X - 0.0005 X2
Coefficient of Performance
X = Wastewater Temperature, °F
5—29 Air to Air Heat Pumps Typical Performance Curve
Y = 59 - 0.84 X Typical Structure Heat Loss,
thousand Btu/hr
X = Outside Temperature, °F
Y = 11.5091 + 1.2769 X - 0.0054 X Heat Pump
Capacity
Y = 0.8225 + 0.0519 X - 0.0004 X Coefficient of
Performance
5-30 Water to Water/Water to Air Heat Pumps
Construction Cost
log Y = 3.026 + 0.1483 (log X) + 0.1530 (log X)
- 0.0122 (log X)3
Y = Construction Cost, dollars '
X = Heat Pump Capacity, thousand Btu/hr
5-31 Water to Water/Water to Air Heat Pumps
0 & M Labor Requirements
log Y = 0.2900 + 0.2924 (log X) + 0.1916 (log X)2
- 0.0253 (log X)3
Y • 0 5, M Labor, hr/yr
X i Heat Pump Capacity, thousand Btu/hr
5-32 Water to Water/Water to Air Heat Pumps
Maintenance Material Costs
log Y = 0.4946 + 1.0205 (log X) - 0.0819 (log X)2
+ 0.0079 (log X)3
Y = Maintenance Material, dollars/yr
X - Heat Pump Capacity, thousand Btu/hr
5-33 Water to Water/Water to Air Heat Pumps Energy Operating Conditions:
Requirements COP = 2.8
„ ... 1.0 . , -,,„ . , Outside Temperature = r>0"F
Y = 0.95 X for 8,760 operating hr/yr
Y = 0.49 XKO for 4,380 operating hr/yr
Y = 0.13 X1'0 for 1,000 operating hr/yr
Y = Electricity Required, thousand kwh/yr
X = Heat Pump Capacity, thousand Btu/hr
74
-------
Figure
Nuirber Operation, Process, and Equation Describing Design Conditions, Assumptions and
From EPA Energy Requirements Effluent Quality
430/9-77-011
5-34 Air to Air Heat Pumps Construction Cost
log Y = - 0.1984 + 0,3145 (log X) + 0.1484 (log. X)2
- 0.0143 (log X)3
Y = Construction Cost, thousand dollars
X = Heat Pump Capacity, thousand Btu/hr
5-35 Air to Air Heat Pumps O&M Labor Requirements
log Y - -0.0781 + 0.5929 (log X) + 0.1290 (log X)2
- 0.0112 (log X)3
Y = 0 4 M Labor, hr/yr
X = Heat Pump Capacity, thousand Btu/hr
5-36 Air to Air Heat Pump Maintenance Material Costs
log Y = 1.0960 + 0.4990 (log X) + 0.0868 (log X)2
- 0.0072 (log X)3
Y = Maintenance Material, dollars/yr
X = Heat Pump Capacity, thousand Btu/hr
5-37 Air to Air Heat Pump Energy Requirements Operating Conditions:
Y = 1.18 X°'98 for 8,760 operating hr/yr ^ =.2'*
, 0 £•; Outside Temperature
Y = 0.53 X ' for 4,380 operating hr/yr
Y = 0.13 X ' for 1,000 operating hr/yr
Y = Electricity Required, thousand kwh/yr
X = Heat Pump Capacity, thousand Btu/hr
75
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APPENDIX B
RAW WASTEWATER CHARACTERISTICS (Wesner et al. , 1978)
Concentration
Parameter mg/1, Except pH
Biochemical Oxygen Demand 210
Suspended Solids 230
Phosphorus, as P 11
Total Kjeldahl Nitrogen, as N 30
Nitrite plus Nitrate 0
Alkalinity, as CaCO- 300
pH 7.3
77
-------
APPENDIX C
SLUDGE CHARACTERISTICS (Wesner et al., 1978)
Sludge
Type
Primary
Primary + FeCl_
Primary + Low
Lime
Primary + High
Lime
Primary + W.A.S.a
Primary +
(W.A.S. +FeCl3)
(Primary + Fed )
+ W.A.S.
W • A» o •
W.A.S. +FeCl
Digested Primary
Digested Primary
+ W.A.S.
Digested Primary
+ W.A;S. + FeCl
Tertiary Alum
Tertiary High
Lime
Tertiary Low
Lime
Total
Solids
(wt Percent
of Sludge)
5
2
5
7.5
2
1.5
1.8
1.0
1.0
8.0
4.0
4.0
1.0
4.5
3.0
Sludge Solids
(Ib/mll gal)
Total
Solids
1151
2510
4979
9807
2096
2685
3144
945
1535
806
1226
1817
700
8139
3311
Volatile
Solids
690
1176
2243
4370
1446
1443
1676
756
776
345
576
599
242
3219
1301
Volatile
Solids
(wt
Percent
of Total
Solids)
60
47
45
45
69
54
53
80
50
43
47
33
35
40
39
Sludge
Volume
(gal/mil
gal)
2,760
16,500
11,940
15,680
12,565
21,480
20,960
11,330
18,400
1,210
3,680
5,455
8,390
21,690
13,235
w.A.S. = Wasted activated sludge.
79
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LITERATURE CITED
Benjes, H. H. (1978) Small community wastewater treatment facilities—
biological treatment systems. USEPA, Technology Transfer, Design
Seminar Handout, Cincinnati, Ohio.
Gulp, G. L. (1978) Alternatives for wastewater treatment at South Tahoe,
CA. Paper presented at the 51st Annual Conference of the Water
Pollution Control Federation, Anaheim, CA, October 1978.
Gulp, R. L., and G. L. Culp (1971) Advanced wastewater treatment.
Van Nostrand Reinhold Company, New York, N.Y.
Environmental Protection Agency (1978) Attachment E to USEPA Program
Requirements Memorandum #PRM 79-3 issued 15 November 1978, to
provide guidance on land treatment alternatives.
Garber, W. F., G. T. Ohara, and S. K. Raksit (1975) Energy-wastewater
treatment and solids disposal. Journal of the Environmental
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Hagan, R. A., and E. B. Roberts (1976) Energy requirements for waste-
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Jacobs, A. (1977) Reduction and recovery: Keys to energy self-
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Mills, R. A., and G. Tchobanoglous (1974) Energy consumption in waste-
water treatment. In: Energy, Agriculture and Waste Management,
W. J. Jewell, Editor. Ann Arbor, Michigan: Ann Arbor Science
Publishers, Inc.
Smith, Robert (1973) Electrical power consumption for wastewater
treatment, U.S. Environmental Protection Agency, Cincinnati, Ohio,
EPA R2-73-281.
Tchobanoglous, G. (1974) Wastewater treatment for small communities.
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Energy conservation in municipal wastewater treatment. MCD-32. EPA
430/9-77-011. Prepared for the U.S. Environmental Protection Agency,
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Wesner, G. M., and B. E. Burris (1978) Energy comparisons in waste-
water treatment. Paper presented at the 51st Annual Conference
of the Water Pollution Control Federation, Anaheim, California,
5 October 1978.
81
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Wesner, G. M., and W. N. Clarke (1978) There is a lot of energy in
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Association, p. 70-79, July 1978.
Zarnett, G. D. (1976) Energy requirements for wastewater treatment
equipment. Applied Science Section, Pollution Control Branch,
Ministry of the Environment, Ontario, Canada, TN 7008.
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82
*U S GOVERNMENT PRINTING OFFICE: 1980 341-082/147
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