WATER POLLUTION CONTROL RESEARCH SERIES • 17090 — 07/70
Cost to the Consumer
for Collection and Treatment
of Wastewater
U.S. ENVIRONMENTAL PROTECTION AGENCY
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WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Series describes
the results and progress in the control and abatement
of pollution in our Nation's waters. They provide a
central source of information on the research, develop-
ment, and demonstration activities in the water research
program of the Environmental Protection Agency, through
inhouse research and grants and contracts with Federal,
State, and local agencies, research institutions, and
industrial organizations.
Inquiries pertaining to Water Pollution Control Research
Reports should be directed to the Chief, Publications
Branch (Water), Research Information Division, R&M, Environ-
mental Protection Agency, Washington, D.C. 20460.
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COST TO THE CONSUMER FOR COLLECTION AND TREATMENT
OF WASTEWATER
by
Robert Smith
Richard G. Eilers
Advanced Waste Treatment Research Laboratory
Cincinnati, Ohio
for the
Office of Research and Monitoring
ENVIRONMENTAL PROTECTION AGENCY
Project #1.7090---
July, 1970
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Price $1.00
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EPA Review Notice
This report has been reviewed by the Environmental
Protection Agency and approved for publication.
Approval does not signify that the contents
necessarily 'reflect the views and policies of
the Environmental Protection Agency, nor does
mention of trade names or commercial products
constitute endorsement or recommendation for
use.
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ABSTRACT
The national average per capita cost for collection and treatment
of municipal wastewater is computed based on the 1968 Inventory
of Municipal Waste Treatment Facilities in the United States and
per capita cost relationships for building and operation collection
and treatment facilities. All costs are given per capita served
with treatment facilities using the level of treatment existing
in 1968. Total cost was computed as $19.80 per capita per year.
Of this total, $15.31 represents amortization charges and $4.49
represents current charges. The total cost can also be broken
down as $13.34 for collection, $4.38 for treatment and $2.08 for
overhead such as customer services, administrative, and general.
The cost of collection is, therefore, about three times as
expensive as treatment.
Nationally, about 23% of the total cost is paid as sewerage usage
charges. This represents about 0.1% of National Personal Consump-
tion Expenditures. Expenditure for water supply averaged $13.42
per capita per year and this is about equal to the amount paid by
the consumer in user charges for water supply.
The current status of collection and treatment in the United
States is discussed and estimates are made of needed additional
expenditure.
111
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CONTENTS
Page
Conclusions 1
Recommendations 3
Introduction 5
Water Contaminants 7
Facilities Required 9
Status of Collection and Treatment in the 17
United States
Cost Relationships 21
Cost of Municipal Collection and Treatment 41
Cost of Industrial Wastewater Treatment 53
Evaluation of the Treatment Backlog 59
Full Cost of Collection and Treatment 63
Governmental Expenditure for Grants-in-Aid 71
Cost Comparison Between Collection and Treatment, 75
Related Services and Personal Consumption
Expenditure
References 83
Appendix 85
v
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FIGURES
No.
Page
1 TYPICAL SEWER SYSTEMS 10
2 CONVENTIONAL PROCESSES SYSTEM DIAGRAM 13
3 WASTEWATER TREATMENT PROCESSES FOR USE DOWN- 14
STREAM OF SECONDARY TREATMENT
4 STATUS OF MUNICIPAL WASTEWATER TREATMENT 18
FACILITIES IN THE UNITED STATES
5 MUNICIPAL BOND YIELDS 22
6 FEDERAL WATER QUALITY ADMINISTRATION SEWER 23
AND SEWAGE TREATMENT PLANT CONSTRUCTION
COST INDEX
7 1957-69 CONSTANT DOLLAR CONSUMER PRICE INDEX 24
8 COST OF SEWERAGE COLLECTION SYSTEMS WITHOUT 32
PUMPING STATIONS VERSUS POPULATION DENSITY
9 DENSITY OF AREAS SERVED BY COMBINED SEWERS 33
10 CUSTOMER SERVICE AND ACCOUNTING COSTS 36
11 GENERAL AND ADMINISTRATIVE COSTS 37
12 CAPITAL OUTLAY FOR NEW SEWAGE COLLECTION 68
AND TREATMENT FACILITIES IN CURRENT DOLLARS
13 DISPOSITION OF NATIONAL PRODUCT IN THE UNITED 76
STATES
vz
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TABLES
No. Page
1 MUNICIPAL SEWAGE TREATMENT SUMMARY FOR THE 11
UNITED STATES (1968)
2 ESTIMATED WATER CONTAMINANT CONCENTRATIONS 15
IN EFFLUENT STREAM FROM VARIOUS GROUPS OF
TERTIARY PROCESSES
3 CONSTRUCTION COST RELATIONSHIPS 25
4 CONSTRUCTION COST RELATIONSHIPS 26
5 OPERATING AND MAINTENANCE RELATIONSHIPS 28
6 OPERATING AND MAINTENANCE RELATIONSHIPS 29
7 SEWER MAINTENANCE COST DATA 35
8 CONSTRUCTION COST RELATIONSHIPS 38
9 OPERATING AND MAINTENANCE RELATIONSHIPS 39
10 POPULATION DISTRIBUTION FOR SEWAGE TREATMENT 42
IN THE UNITED STATES (1968)
11 NATIONWIDE AVERAGE CONSTRUCTION COST, DOLLARS 44
PER CAPITA (1968 DOLLARS)
12 NATIONWIDE AVERAGE CONSTRUCTION COST, DOLLARS 45
PER CAPITA (1968 DOLLARS)
13 NATIONWIDE AVERAGE OPERATION AND MAINTENANCE 46
COST, DOLLARS PER YEAR/CAPITA (1968 DOLLARS)
14 NATIONWIDE AVERAGE OPERATION AND MAINTENANCE 47
COST, DOLLARS PER YEAR/CAPITA (1968 DOLLARS)
15 CONSTRUCTION COST FOR SEWERS BASED ON 1968 48
SEWERED POPULATION
16 PER CAPITA LENGTH OF SEWERS IN THE UNITED 49
STATES BASED ON 1968 SEWERED POPULATION
VII
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TABLES
(Continued)
No. P.a9e-
17 NATIONWIDE AVERAGE CONSTRUCTION AND OPERATING 51
AND MAINTENANCE COST FOR TERTIARY WASTEWATER
TREATMENT PROCESSES
18 ESTIMATED VOLUME OF INDUSTRIAL WASTES BEFORE 55
TREATMENT (1964)
19 ANNUAL INVESTMENT REQUIRED TO REDUCE THE 56
EXISTING INDUSTRIAL WASTE TREATMENT DEFICIENCY
IN FIVE YEARS
20 ANNUAL OPERATING AND MAINTENANCE COSTS 57
(1968-1973)
21 SUMMARY OF WASTEWATER COLLECTION AND TREATMENT 60
IN UNITED STATES (1957-1968)
22 ROUGH CALCULATION OF INVESTMENT IN SEWAGE 61
TREATMENT FACILITIES AND ANCILLARY WORKS IN
THE UNITED STATES IN 1968
23 COMPUTATION OF NATIONAL AVERAGE OPERATION AND 64
MAINTENANCE COST FOR TREATMENT PLANTS
24 TOTAL COST OF SEWAGE COLLECTION AND TREATMENT 66
IN 1968 ON A CONTINUOUS CASH FLOW BASIS
25 EXPENDITURES FOR SEWERAGE COLLECTION AND TREAT- 67
MENT IN THE UNITED STATES
26 CONSTRUCTION GRANTS FOR CONSTRUCTION OF WASTE 72
TREATMENT WORKS ADMINISTERED BY FWQA
27 STATE GRANTS-IN-AID FOR SEWERS AND SEWAGE 73
TREATMENT PLANTS (1967)
28 PERSONAL CONSUMPTION EXPENDITURE BY TYPE OF 77
PRODUCT
29 FINANCES OF WATER SUPPLY UTILITIES OPERATED 79
BY LOCAL GOVERNMENTS (1966-67)
vxn
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TABLES
(Continued)
No. Page
30 PERCENT DISTRIBUTION OF GENERAL EXPENDITURE 81
OF MUNICIPALITIES BY FUNCTION 1967
IX
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CONCLUSIONS
The cost of collection and treatment of municipal sewage does
not represent a large fraction of personal consumption expendi-
ture and the cost of public collection and treatment is signi-
ficantly lower than the cost of individual disposal units such
as septic tanks. From the cost estimates presented it would
appear that waste collection and treatment could be placed on
a utility basis by increasing the sewerage charges now paid
by a factor of about 2.5 provided the homeowner continues to
pay for the house connection and municipal sewers as part of
the price of the house or as a special assessment. If the
entire cost of collection and treatment exclusive of the house
connection is to be paid as a user charge, the amount of the
charge could exceed the present cost of water supply by about
40%.
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RECOMMENDATIONS
In recommending a course of action to conserve the water resources
of the Nation it is essential that we understand the economic
impact of each alternative plan. For example, the effect on
prices paid by the consumer for manufactured goods caused by
forcing the industrial polluter to treat liquid wastes before
discharge should be evaluated. The impact on the housing indus-
try caused by regulations demanding adequate collection and
treatment of wastewater should be studied. The feasibility of
establishing collection and treatment of wastewater as a utility
which could charge the user an equitable rate should be studied.
The effect on unit treatment cost caused by imposition of effluent
standards, especially in smaller plants, should be evaluated to
understand the burden this would place on the smaller community.
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INTRODUCTION
Over the past year or two in the United States, concern over
deterioration of the environment has grown significantly. As
a result, the public is showing an increasing tolerance for
paying the cost of protecting our air, land, and water resources.
It is a truism that the public will ultimately be required to
pay the full cost of all forms of pollution control. Thus, the
public rather than engineers, economists, or governmental
officials must decide the level of expenditure and the corre-
sponding degree of pollution abatement which best matches the
life style to which they aspire. The role of engineers and
economists is to present the public with the technical and
cost related information necessary for rational decision making.
Given the present high level of sophistication of the American
Public there is little doubt that the public will decide in
favor of increased expenditures for pollution abatement. The
role of Federal Government is to educate the public and to urge
the public to make decisions which are in the best interest of
the Nation as a whole. This paper is intended to encourage
and facilitate this educational process by attempting to assess
in terms of dollars/capita/year the true cost of building and
operating collection and treatment facilities for sewage and
industrial wastewater. These facilities are required to protect
our waterways from the vast pollutional load now being discharged
so that our waterways will again be available for public
recreational and aesthetic use.
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WATER CONTAMINANTS
Contaminant species carried by wastewater which are known to
have a detrimental effect on receiving streams can be roughly
classified as carbon, nitrogen, and phosphorus. Carbon (organic)
compounds serve as the principal food for aquatic microorganisms
which if allowed to proliferate will deplete the dissolved
oxygen reserves of the stream and create septic and aesthetically
objectionable conditions in the stream. The concentration of
organic contaminant present in wastewater is measured as Chemical
Oxygen Demand (COD) or Total Organic Carbon (TOC) expressed as
milligrams/liter. The fraction of the organic contaminant which
is readily available as food for microorganisms is expressed
as Biochemical Oxygen Demand (BOD) measured as mg/1. This
test (BOD) consists of observing the dissolved oxygen depletion
which occurs over a 5-day period in a sample of the water under
controlled laboratory conditions. There is some disagreement
among experts concerning which of the above tests should be used
to measure the true capacity of wastewater to deplete dissolved
oxygen resources. Unanimous agreement exists, however, on the
need to remove organic contaminants from wastewater before
discharge to the receiving stream.
Phosphorus and nitrogen discharged to the receiving stream will
encourage the growth of nuisance aquatic plants such as blue-
green algae. The need for removal of nitrogen and phosphorus
from all wastewater is not as well established as the need for
removal of organic contaminants. These are specific cases,
however, where removal of nutrients is clearly required.
Removal of phosphorus is generally believed to be a better
investment than removal of nitrogen because of the ability of
some aquatic plants to fix nitrogen from the atmosphere.
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FACILITIES REQUIRED
Facilities needed to collect and treat sewage can be enumerated
as
1. House connection
2. Municipal sewer system consisting of laterals and trunk
sewers
3. Interceptor sewers which collect from the trunks and
deliver the sewage to the treatment plant
4. Pumping stations
5. The treatment plant which removes contaminants from the
water
6. Outfall sewer which delivers the treated sewage to the
receiving stream.
These facilities are illustrated in Figure 1.
In addition to the sanitary sewer, storm sewers are often
provided to collect the runoff from the paved areas of the
city- Some urban communities collect both sanitary sewage
and storm water in a common or combined sewer system. This
has the disadvantage of hydraulically overloading the treat-
ment plant when heavy rains occur, flooding basements, and
also reducing the velocity of flow in the combined sewers which
results in deposition of untreated particulate material in the
combined sewer. To avoid hydraulic overload at the treatment
plant, sewerage systems using combined sewers normally bypass
the plant during high flow periods resulting in high pollutional
loads on the receiving stream. This lack of treatment is
ameliorated by the fact that the stream is better able to
assimilate the increased pollutional load at high flow conditions.
The 1968 Inventory of Municipal Waste Treatment Facilities (!)
summarized in Table 1 shows that of the 12,911 communities with
sewer systems about 1794 or 14% are equipped with combined sewers.
The processes used to treat wastewater are roughly classified
as primary, secondary, and tertiary treatment. Primary treatment
normally consists of removing particulate contaminants by means
of sedimentation. The sludge formed is then reduced in volume by
means of anaerobic digestion, dewatered by means of vacuum
filtration, centrifugation, or sludge drying beds and finally
disposed of by application to the land or incineration. An
increased fraction of the particulate matter can be removed by
addition of chemicals such as alum, iron salts, or polyelectrolytes
The process modification is often referred to as intermediate
treatment.
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S«w09« Trtolmenl Wofkl
Typical Sewer Systems
SOURCE: National Association of Counties/Research Foundation, Community
Action Program for Water Pollution Control, Library of Congress
Card Number 65-29251.
FIGURE 1
10
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MUNICIPAL SEWAGE TREATMENT SUMMARY FOR THE UNITED STATES
Number of communities with sewer systems
Discharging raw sewage only
Discharging treated sewage only
Discharging both raw and treated sewage
Type sewe rs-numbe rs of communities:
Separate
Combined
Both separate and combined
Not stated
I960 Census population of sewered communities
Estimated populat ion :
Connected to sewers
Discharging raw
Discharging treated
Number of fac i 1 i ties -total
Discharging raw
Discharging treated
TREATMENT
Treatment plants-total (including 98 unknown
Minor
Primary
Intermediate
Secondary
Tertiary
Estimated population served by
Minor treatment" .
Primary treatment
Intermediate treatment
Secondary treatment
Tertiary treatment
Total
Number
12,911
1 ,416
11 ,422
73
10, i!7
1, 173
621
HOC)
12 '3 , K4 3 , 1O7
140,226,049
9,541 ,278
1 3O,684, 771
14,12';!
1 , 558
12, 565
degree ) 12 , 56 5
47
2, 384
75
9,951
10
1 , '360, 87O
36,947, 397
5,857,690
85, 640, 764
325, 530
130,132,251
Pe rcent
1
100.O
11.0
88. 5
. 5
85.2
9. 7
. 5
1OO.O
6.8
93. 2
1OO.O
11.0
89.0
1
1OO.O
.4
19.1
.6
79.8
.1
l.O
28.4
4. 5
65.8
. 3
^Percentage bases exclude 98 unknown or not stated categories
"Less than sedimentation
TABLE 1
11
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By secondary treatment we normally mean some form of biological
treatment which converts dissolved organic compounds to micro-
organisms which can then be settled out and removed in the
final clarifier. A process diagram for an activated sludge
secondary plant is shown in Figure 2. The activated sludge
process consists simply of a stirred tank supplied with atmos-
pheric air in which a dispersed floe composed of organic
particulate and active microorganisms is maintained. The
floe acts as a support on which new microorganisms grow by
using the dissolved contaminants as food. The sludge from the
primary and secondary clarifiers or settlers is disposed of in
a manner similar to the primary plant. Trickling filters can
be used in place of the activated sludge process. A trickling
filter consists of a packed column of stones or other media to
which a slime of microorganisms clings. The wastewater is
trickled over the fixed media and the microorganisms in the
slime use the dissolved nutrients to grow more slime. The
slime sloughs off periodically and is removed in the final
clarifier.
Tertiary treatment consists of processes used downstream of the
secondary plant to remove an additional fraction of the contami-
nants. Microscreening is sometimes used to remove particulatfc
which escapes over the final clarifier weirs. Lime clarification
can be used to remove additional particulate and to remove most
of the phosphorus. Dual media filtration is used downstream
of the lime clarification process to remove the haze of inorganic
particulate which often escapes the lime clarification process.
To polish an effluent for reuse, granular carbon adsorption can
be used to remove the last traces of dissolved and/or particulate
organic material. A diagram of tertiary treatment process trains
is shown in Figure 3.
Normal raw domestic sewage will measure about 20O mg/1 for both
5-day BOD and volatile suspended solids. Removal of 5-day BOD
in the primary settler averages about 35% which results in a
5-day BOD of about 130 mg/1 for the feed stream to the activated
sludge process. The activated sludge process, if operating at
peak efficiency, will remove about 90% of the remaining 5-day BOD.
A good secondary effluent from the activated sludge process will,
therefore, measure about 13 mg/1 5-day BOD. These efficiencies
are achieved only under ideal conditions so that the target for
performance is often taken as 9O% of 5-day BOD across the entire
plant or even 85% removal across the plant. The estimated
effectiveness of tertiary processes is shown in Table 2.
12
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rONVENTfONAL PROCESSES SYSTEM DIAGRAM
FIGURE 2
13
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7o
MS = Microscreening
LC - Lime Clarification
MMF - Multi-Media Filtration
AS = Ammonia Stripping
GCA = Granular Carbon Adsorption
RC = Recarbonation
WASTEWATER TREATMENT PROCESSES FDR USE DOWNSTREAM OF SECONDARY TREATMENT
FIGURE 3
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ESTIMATED^ WATER CONTAMINANT CONCErfTRATIONS IN
EFFLUENT STREAM FROM VARIOUS GROUPS OF TERTIARY PROCESSES
J)
3 a-
W(
0 <«
I-1
Ln
O. Secondary Effluent
1. Microscreening or
Rapid Sand Filtration
(la, 2, 7a)
2. Granular Carbon Adsorption
(Ic, 4, 5, 7c)
3. Lime Clarification
(Ib, 2, 3, 3a, 4, 7b)
4. Lime Clarification +
Multi-Media Filtration
(Ib, 2, 3, 3a, o, 5, 7c)
5. Line Clarification +
Aranonia Stripping
(Ib, 2, 3, 4, 7b)
6. Lime Clarification +•
Ammonia Strip>ping +
Granular Carbon Adsorption
(Ib, 2, 3, 4, 5, 7c)
>E=:euEHE z e a. e Remark^
20 13 oO 20 17 10
6 7.5 47 ID 17 10 70% Removal of Suspended Solids
2 2 10 3 17 10 90?S Removal of Suspended Solids
2 6 44 15 17 1 90% Removal of Suspended Solids
<1 5 42 14 17 1 9955 Removal of Suspended Solids
2 6 44 15 2 1 90% Removal of Suspended Solids
<1 1 9 3 2 1 99% Removal of Suspended Solids
*Dissolved
TABLE
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STATUS OF COLLECTION AND TREATMENT IN THE UNITED STATES
The goal of the Federal Water Quality Administration for municipal
wastewater treatment was enunciated in the 1968 Cost of Clean Water
Report!2) as adequate treatment for the total urban population
of the United States by 1973. Adequate treatment was later
defined as equivalent to secondary treatment. National effluent
standards for discharge to receiving streams have yet to be
established. Most States, however, now have effluent standards
for BOD removal and disinfection. The range for BOD removal
is between 80-9O% with 85% the most quoted standard. Twenty-
nine States require disinfection of secondary effluent although
some require it only seasonally or for discharge to specific
streams. The definition of adequate treatment used here will
be a treatment train terminated by one of the following processes :
activated sludge, extended aeration, or trickling filter.
The definition of urbanized area is the same as that used by
the Bureau of Census. The Bureau of Census defines urbanized
area as all incorporated area with 1OO or more closely settled
dwellings and all unincorporated areas with a population density
of 1000 or more inhabitants per square mile. Since the average
household size in 1968 was 3.23 persons, this last definition
of urban area is equivalent to one household per two-acre tract.
The total and urban populations of the United States are shown
plotted versus time in Figure 4. Population projections were
taken from the work of Resources for the Future reported in
Committee Print No. ?(3). The population served by sewer
systems and treatment plants were taken from the 1957, 1962,
and 1968 Inventories of Municipal Waste Treatment Facilities(4)*(5),(1)
The population served by potable water treatment and distribution
facilities were taken from Statistical Summary of Municipal Water
Facilities in the United States, January 1, 1963(6).
Figure 4 shows in a rough way the present status of collection
and treatment in the United States. The gap or backlog for
municipal sewer systems appears to be relatively small although
it will be shown later that installation of new sewers is more
costly than construction of new plants. Some level of treatment
appears to be available for a substantial fraction of the urban
population. Secondary treatment and particularly the level of
treatment defined above as adequate is available to only about
50% of the urban population. Potable water supply is available
to a population which exceeds the urban population.
17
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280
260
Sewered Population
Total Treated Population
Secondary Treated
Population
Adequate Secondary Treated Population
O
1950
1900
1970
Year
1980
1990
STATUS OK MUNICIPAL WASTEWATER TREATMENT FACILITIES
IN THE UNITED STATES
FIGURE 4
18
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The data presented in Figure 4 show clearly the need for increased
expenditures to overcome the backlog of needed construction. The
FWQA has proposed overcoming this backlog within a five-year
period. The cost associated with meeting the goal of adequate
secondary treatment for the total urban population will be
assessed, but first the cost of building and operating plants
and sewer systems will be developed.
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COST RELATIONSHIPS
Cost associated with constructing and operating sewerage systems
and treatment facilities are of two basic kinds. The first
is the cost of constructing the physical works which is normally
paid for by the sale of general obligation municipal bonds.
The cost of construction is then repaid in equal yearly payments
over the useful life of the structure. Each payment (amortization
cost) includes interest on the outstanding debt plus an amount
which will insure that the bonds are fully redeemed at the end
of the useful life of the structure. To provide for periodic
payments, bonds can be sold with graduated maturity dates. The
cost of repaying the construction cost and the interest charges
is often expressed as level debt service. The life of sewers
is normally taken as 50 years and the life of treatment facilities
as 25 years. If the bonds have a yield of 5%, the yearly
expense for amortizing sewers would be equal to the construction
cost multiplied by the factor 0.05478. The corresponding factor
for treatment plants would be O.O7095. The interest rate which
must be paid by the municipality is related to the credit rating
of the community. For example, the yield or effective interest
rate for bonds(') with rating of Aaa and Bbb is shown in Figure
5. Construction cost can be expressed as dollars/capita while
amortization cost is expressed as dollars/capita/year. It should
be noted that the cost of construction, like all cost, varies with
time. The FWQA construction cost indexes for sewers and treatment
plants are shown in Figure 6. The level has been adjusted to
be 100 at the 1957-59 point used by the Dept. of Commerce.
The second kind of expense (current expense) is associated with
operating and maintaining the equipment and structures. Examples
of this kind of expense are sewer maintenance charges, operating
and maintenance cost for treatment, customer service and account-
ing, and general and administrative cost. Current expense is
related to salaries, fringe benefits, purchases of chemicals and
other kinds of supplies. Current expense is expressed as dollars/
capita/year. The cost of current expenses also depends on time
and can be adjusted by means of the Bureau of Labor Statistics
Index for Residential Water and Sewerage Services!8). This index
is shown in Figure 7.
Construction cost relationships for various kinds of plants are
shown in Tables 3 and 4. Relationships derived by R. L. Michel
of Construction Grants and Engineering Branch of WQo(^) were
derived by fitting log-log regression equations to cost data for
21
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MUNICIPAL BOND YIELDS
'.U
ft . Ol
4.0
Grade Bbb Securities
Grade Aaa Securities
1 .0
Year
•>0 SH OO 02 04 00
FIGURE j
22
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to
140
130
120
110
1OO
FEDERAL WATER QUALITY ADMINISTRATION
SBWER AMD SEWAGE TREATNBNT PLANT
CONSTRUCTION COST INDEX
(1957-59 = 1OO)
Treatment
Plant Index
Year
1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970
FIGURE 6
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,--,u CONSTANT DOLLAR
CONSVMER PRICE INDBX
14"
and Sewerage
Se rvices
Standard
Consutscr Price Index
Year
FIGURE
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CONSTRUCTION COST RELATIONSHIPS
in the form Y = aX
Type of Treatment Facility
1. Waste Stabilization Ponds
2. Primary Sedimentation Plant
3. Activated Sludge Plant
4. Trickling Filter Plant
5. Upgrading Primary to Activated
Sludge
6. Ancillary Works*
Value for a
Value for b
2863.14
675.68
912.73
945.02
1484.03
-.6050
-.14274
-.3088
-.31O5
- . 4073
86.26
-.0896
where, y = construction cost> dollars per capita (1968 dollars)
X = design population, number of persons
a 3c b = constants
Source: R. L. Michel, Construction Grants and Engineering Branch, FWQA
#Ancillary Works Interceptors, Outfalls, and Pumping Stations
TABLE 3
25
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CONSTRUCTION COST RELATIONSHIPS
in the form Y = aX
Type of Treatment Facility Value for a Value for b
1. Primary Sedimentation Plant 514.90 -.2890
2. Activated Sludge Plant 383.75 -.2100
3. Trickling Filter Plant 317.58 -.2OOO
where,
Y construction cost, dollars per capita (1968 dollars
X = design population, number of persons
a 3e b - constants
Source: Robert Smith, "Cost of Conventional and Advanced Treatment
of Wastewaters"
TABLE 4
26
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plants for which FWQA contributed grant-in-aid funds. The
relationships attributed to Smith were found by updating and
recasting the data from Reference 10. The FWQA construction
cost index used was the mean for 1968 and equalled 123.55.
The sewer index for 1968 was 129.57- Corresponding operating
and maintenance cost for various kinds of plants are shown
in Tables 5 and 6.
The system of sanitary sewers which collects the wastewater
from individual dwellings and delivers it to the sewerage
treatment plant is composed of several components (See Figure 1).
The first is the house connection which connects the house or
business establishment to the street sewer. The average length
of the house connection is 60 feet and the size of the pipe is
4-6 inches diameter. The municipal sewer system is made up of
concrete sewer pipe ranging in diameter from 6-42 inches
diameter. The mean effective diameter for cost estimates is
sometimes taken as 10 inches. Manholes are placed at an average
interval of 40O feet along the municipal sewer to facilitate
changes in direction and grade and also to provide access for
cleaning and inspection. Sewer systems are designed for gravity
flow, but at times it is necessary to install pumping stations
and force mains where gravity flow is not possible.
One of the first attempts to price the sewerage system was made
by Isard and Coughlin(-'-l) . jn this document, a development of
2480 dwellings built on the outskirts of a city of 25,000
population was studied. Three population densities, 1 dwelling
per acre, 4 dwellings per acre, and 16 dwellings per acre were
studied. These were designated as low, medium, and high density
housing. If we assume 3.23 persons per household (1968), the
three densities correspond to 3.23 persons per acre, 13.4 persons
per acre and 57.7 persons per acre respectively. The cost
quoted by Isard and Coughlin applied to 1953. These population
densities can be compared to existing cities in 1960 as follows:
Austin, Texas 6.42 persons/acre
Milwaukee, Wis. 12.9 persons/acre
Brooklyn, NY 58.4 persons/acre
Manhattan, NY 117. persons/acre
The average population density for the APWA study(12) of storm and
combined sewers was found to be about 8.6 persons/acre.
27
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OPERATING AND MAINTENANCE RELATIONSHIPS
in the form Y = aX
Type of Treatment Facility Value for a Value for b
i. Waste Stabilization Ponds 17.38 -.4172
2. Primary Sedimentation Plant 24.95 -.2634
T. Activated Sludge Plant 3O.1O -.246O
4. Trickling Filter Plant S4.99 -.3569
where,
Y operating and maintenance cost, dollars per year/capita
(19hH dollars )
X = design population, number of persons
a ^ b = constants
Source: R. L. Michel, Construction Grants and Engineering Branch, FWQA
TABLE 5
28
-------
OPERATING AND MAINTENANCE RELATIONSHIPS
in the form Y = aX
Type of Treatment Facility Value for a Value for b
1. Primary Sedimentation Plant 8.44 -.iy5O
2. Activated Sludge Plant 29.67 -.24OO
3. Trickling Filter Plant '52.62 - . 'MOO
whe re,
Y = operating and maintenance cost, dollars per year/capita
(19fc>B dollars)
X = design population, number of persons
a .% b = constants
Source: Robert Smith, "Cost of Conventional and Advanced Treatment
of Wastewaters"
TABLE b
29
-------
Isard and Coughlin assumed that for the low density housing no
municipal sewers would be provided. For the medium density
community it was computed that 17.26 miles of sewer would be
required. For the high density community 6.91 miles of sewer
were needed. The cost was based on an equivalent 10 inch
diameter sewer pipe buried 6 feet in the ground. The total
investment in terms of 1953 dollars for the medium density
community was $482,410. For the high density community the
investment was $182,520. Using the FWQA Sewer Construction Index,
the equivalent 1968 costs would be $773,786 and $292,762.
Since the number of persons served would be 2480 x 3.23 or 8010,
the per capita cost for constructing the sewerage collection
system in 1968 would be $96.48 for medium density and $36.42 for
the high density community -
Isard and Coughlin also computed the cost of storm sewers for
the two communities. The average effective size of pipe was
taken as 42 inches. In terms of 1968 dollars the investment for
storm sewers in the medium density community was $1,038,510 and
$379,956 for the high density community. The per capita con-
struction cost for storm sewers was, therefore, $128.4O per capita
for the medium density community and $47.44 per capita for the
high density community.
Isard and Coughlin assumed that no sewage pumping would be
necessary, and that the life of the sewers would be 5O years.
In a recent unpublished study by American Public Works Association^3)
the cost of installing sanitary sewers in two communities, 100,000
and 250,000 population, was studied. The average population
density for the smaller city was 8.3 persons per acre while the
density in the larger city was 8.9 persons per acre. Sewer miles
for the 100,000 population city was 264 miles. For the larger
city the sewer miles was 588 miles. An average number of commercial
businesses and manufacturing firms was assumed. The cost of
individual items for the two cities are given below in terms of
dollars per capita.
Population Density 8.3 8.9
House Connections $81.51 $81.80
Municipal Sewers $166.99 $148.77
Manholes $10.46 $9.31
$258.96 $239.88
30
-------
Interceptor and outfall sewers, with pumping, are not included in
either of the two studies, because these facilities are normally
lumped with the treatment plant cost.
If we compare the APWA estimates with Isard and Coughlin estimates,
we must use the same basis. Isard and Coughlin did not include
house connections. The cost of municipal sewers and manholes
from the APWA estimate is $167.45 per capita for the 8.3 persons
per acre density and $158.08 per capita for the 8.9 persons per
acre density. These estimates are shown plotted with the Isard
and Coughlin estimates, in terms of 1968 dollars, in Figure 8.
The equation which relates the cost of municipal sewers to the
population density has the following form:
Sewer Construction Cost, $/capita = $800 (persons/acre)
-0.775
Both the I960 Census(14) and the APWA Storm and Combined Sewer
Study(12) show a relationship between the size of community
and population density. The APWA data was used here because it
is more recent. The relationship is shown by the dotted line in
Figure 9. The relationship has the following form:
Population Density, persons/acre = 0.30 (community size)
The cost of household sewage disposal systems was studied by
Thomas, Coulter, Bendixen, and Edwards (^5). This study, which
was reported in 1960, attempted to optimize the household
system. Optimum costs were estimated for three systems; septic
tanks, aerobic treatment units, and cesspools. Poor, average,
and good soil conditions were considered. Costs were expressed
as present values. For average soil the present value of the
septic tank system was given as $1,059. The present value was
$1,351 for the aerobic system and $1,348 for the cesspool.
Updating these costs to the 1968 level by means of the FWQA
Treatment Plant Index gives $1,236 for the septic tank, $1,577
for the aerobic unit and $1,573 for the cesspool. If we assume
an interest rate of 6%, the yearly per capita costs computes
as $22.93/year/capita for the septic tank, $29.29/capita/year
for the aerobic unit and $26.09/capita/year for the cesspool.
Downing' ' reported the cost of a 1050 gallon septic tank with
10O feet of tile in Madison, Wisconsin on February 28, 1967, as
$537.50. Downing estimated the life of the tank as 50 years and
the life of the tile field as 25 years. Downing assumed that
the septic tank system would be inspected and pumped once every
two years. The cost of inspection and pumping was estimated as
$50.
31
-------
100O
Q.
«
O
COST OF SEWERAGE COLLECTION SYSTEMS
WITHOUT
PUMPING STATIONS
VERSUS
POPULATION DENSITY
196R dollars
1OO
O
•o
at
Ol
OAPWA estimates
Isard and Coughlin estimates
10
10 1OO
Population density, persons/acre
KTGUKE rt
32
-------
100.0 I
DENSITY OF AREAS SERVED BY COMBINED SEWERS
10.0|
tt)
u
u
a
\
c
0
•H
a
o
u>
>,
•4->
•H
t/>
C
Y = .30 * X ** .304
i.o
0
D.
Population of Community
100
1,000
10,000
100,000
1,000,000
10,000,000
FIGURE 9
-------
Recent inquiries in the Cincinnati area revealed that Health
Department standards require one 1OOO gallon septic tank per
household with a minimum of 900 square feet of surface area
for the gravel leaching bed. The construction cost of the
septic tank installation ranges from $900 to $1OOO. Inspection
and cleaning is required every two years at a cost of between
$30 and $35. Amortizing the construction cost over a 35 year
average life at 6% interest gives a yearly per capita cost of
$20.28. Adding $15 per year for maintenance gives a total per
capita cost of $35.28/year.
In a study(17) conducted by the Constructions Grants and
Engineering Branch of FWQA, the cost components in 733 federally
funded sewer construction projects were analyzed. This study
showed that roughly one-half of the construction cost was
attributable to lump sum items such as pumping stations, inverted
siphons, and flow control devices. It will be assumed here
that the cost of pumping stations is included in the cost of
ancillary works which was supplied by R. L. Michel of FWQA and
shown in Table 3.
The cost of maintaining municipal sewers is conveniently expressed
as cents/foot of sewer/year because the principal expense is
labor. Bourlon(l^) of Midwest City, Oklahoma reported an average
cost of 6 cents per foot per year in 1969. Sewer maintenance
cost data gleaned from financial reports of a number of cities is
shown in Table 7. Averaging the first six values in the table
gives an average cost of 6 cents per foot per year. This estimate
will be used in this report.
In addition to expenses directly related to owning and operating
the facilities two additional types of expenses are incurred.
The first is called Customer Service and Accounting, the second
General and Administrative. These overhead expenses were gathered
from about ten municipal financial reports. Data from an
additional ten cities was supplied by Mr. Don Parkhurst of Black
and Veatch Engineers, Kansas City, Missouri(19). These data are
shown plotted in Figures 10 and 11. Regression relationships are
shown on the plots.
Cost estimates for tertiary processes were reported by Smith and
McMichael(20) in the Robert A. Taft Water Research Center Report
No. TWRC-9. These estimates which were in terms of construction
dollars and operation and maintenance cost in cents/1000 gallons
have been converted to dollars per capita and dollars/capita/year
by assuming the standard 100 gallons/capita/day. The cost
relationships in the new form are shown in Tables 8 and 9.
34
-------
SEWER MAINTENANCE COST DATA
OJ
Ui
City
Phoenix, Ariz.
Richmond, Ind.
Knoxvillc, Tenn.
Walla Walla, Wash.
Alexandria, Va.
South Bend, Ind.
Columbus, Ohio
Levittown, Pa.
Allegheny County Sanitary
Authority
East Bay
Philadelphia, Pa.
Decatur, 111.
Miles of Sewers QAM Cost($)
O&M, Year of
«
-------
lu.
CUSTOMER SERVICE AND ACCOUNTING COSTS
1 .
O - ANNUAL REPORTS
O - PAIUC1RJRST
Y 7S.JJ * X ** (-.43)
i , (KH) ,i )(>(>
COMMUNITY mPULATION
FK'.t'RI-; lo
36
-------
*»'..
"V,
l.Oi)
OS
to
a.
GENERAL AND ADMINISTRATIVE COSTS
*"...
o o
Y= 22O)
ANNUM.
I'ARKJIUKST
] Of),()()()
a)MMUNITY
I-'ICUIJE 11
37
-------
CONSTRUCTION COST RELATIONSHIPS
in the form Y = aX
Type of Treatment Value for a
1. Microscreening 9.37
2. Filtration 207.10
3. Two-Stage Lime Clarification
(less than 10 mgd) 140.86
(greater than 10 mgd) 50.08
4. Lime Recalcination 1903.20
5. Ammonia Stripping 22.71
6. Carbon Adsorption
(less than 10 mgd) 1439.59
(greater than 10 mgd) 7b.01
Value for b
-.1190
-.34OO
-.2000
-.1750
-.5000
-.1000
-.4000
-.1400
where,
V = construction cost, dollars per capita (19oH dollars)
X = design population, number of persons
a 3c b = constants
Source: Robert Smith and Walter F. McMichael, "Cost and Performance
Estimates for Tertiary Wastewater Treating Processes"
TABLE 8
38
-------
OPERATING AND MAINTENANCE RELATIONSHIPS
b
in thq form Y - aX
Type of Treatment Fac1lity
Value for a
Value for b
1. Microscreenincj .30
2. Filtration 51.31
3. Two-Stage Lime Clarification
(less than 1O mgd) 148.61
(greater than 1O mgd) 12.04
4. Lime Recalcination
(less than 1O mgd) 3O.O1
(greater than 10 mgd) 9.36
5. Ammonia Stripping
(less than 1O mgd) 35.49
(greater than 10 mgd) 3.52
6. Carbon Adsorption
(less than 10 mgd) 1418.94
(greater than 1O mgd) 23.9O
7. Two-Stage Lime Clarification
With Disposal or Recalcination
(less than 10 mgd) 33.92
(greater than 1O mgd) 26.44
-.O440
-.3800
-.4400
-.2250
-.3000
-.2080
-.3330
-.1330
-.5500
-.2000
-.2390
-.2160
where ,
Y = operating and maintenance cost, dollars per year/capita
(1968 dollars)
X = design population, number of persons
a & b = constants
Source: Robert Smith and Water F. McMichael, "Cost and Performance
Estimates for Tertiary Wastewater Treating Processes"
TABLE
39
-------
COST OF MUNICIPAL COLLECTION AND TREATMENT
In order to use the capital cost and operating and maintenance cost
relationships to calculate an average cost per capita in the
Nation, the distribution of treatment facilities according to size
must be used. This kind of data is supplied by the 1968 Inventory
of Municipal Waste Treatment Facilities(!). The number of in-
habitants and the number of plants in each population size group
is shown in Table 10.
Traditionally, treatment plants are not constructed to serve the
existing population but to serve the population expected at the
end of the design period, normally taken as 20 years. Projecting
ahead from 1968 to 1988 and from 1973 to 1993 we obtain, in
either case, a ratio of design population to existing population
of about 1,50. The design population for use in constructing new
plants will, therefore, be the product of the existing population
and the excess capacity factor 1.50.
According to a study reported in Volume 1 of the 1969 Cost of
Clean Water Report^ ), a trend towards constructing plants with
larger excess capacity factors has been observed between 1962
and 1968. In 1962, the median capacity of existing municipal
waste treatment plants was between 1.2 and 1.4 times that
required by the existing population. In 1968 this factor had
increased to between 1.4 and 1.6. The excess capacity factor
also increases with the size of the plant. For cities in the
population range between 5O,000 and 500,000 persons, the median
capacity in 1968 was 1.6 to 1.8 times the existing population
and the modal plant size was 2.0 to 2.5 times the existing
population.
The computational scheme (see Appendix) used to find the average
construction cost for the Nation as a whole is described as
follows: The population served in each population size group was
first divided by the number of plants in the group. This number
which represents the average number of inhabitants served per
plant was then multiplied by the factor 1.5 to find the average
design population per plant. Using the design population, the
cost per capita was then found from the appropriate construction
cost relationship. This per capita cost was then multiplied by
the population served to find the construction cost for each
population size group. These population group costs were then
summed over all groups and the total divided by the actual 1968
41
-------
POPULATION DISTRIBUTION
FOR SEWAGE TREATMENT _IN THE UNITED STATES
1968
Population Size Groups
Under SOO
=.OO - 1 ,00(1
1 , OOO - 5 , OOO
5.0OO - 10.0OO
1O.OOO - 25.OOO
25.OOO - 5O,OOO
50.OOO - 10O.OOO
1OO,OOO - 25O.OOO
250.OOO - 5OO.OOO
Over 500,000
Total Sewered Population
Stabilization Ponds
Primary Sedimentation
Communities
1791
2259
5375
1516
12OO
422
203
86
37
22
Pop. Served
603,874
1 ,828,753
12,385,893
9, 570,149
15,504,150
12,697,7OO
13,421,175
14,856,790
13,620,080
45,648,965
Plants
896
816
1334
179
131
36
27
16
15
4
Pop. Served
273,098
571,600
2,327,850
904,900
963,385
444,280
319,235
209,345
64,335
13, 1OO
Plants
156
276
832
269
237
107
53
56
19
15
Pop. Served
111,287
245,841
2,048,489
1,750,960
3,438,355
3,001,825
3,605,920
5,202,805
3,472,445
13,499,405
to
Population Size Groups
Under 5OO
500 - 1,000
1,OOO - 5,OOO
5,000 - 10.0OO
10.0OO - 25,OOO
25,OOO - 50.OOO
50,000 - 100,000
100,000 - 25O.OOO
25O,OOO - 5OO.OOO
Over 5OO,OOO
Activated Sludge
Trickling Filter
Sewered but Untreated Pop.
Plants
261
294
752
242
205
135
77
72
44
27
Pop. Served
90,899
225,677
1,738,430
1,530,225
2,839,385
3,229,805
4,401,615
4,322,060
4,2OO,60O
18,667,965
Plants
188
458
1641
620
495
156
90
68
58
9
Pop . Se rved
74,245
353,435
4,207,595
4,101,426
6,227,810
4,464,355
3,182,085
2,294,635
2,481,290
1,025,100
Pop. Served
71,915
228,925
1,199,535
680,098
1,070,355
639,635
747,480
1,345,440
1,622,125
1,977,400
Source: 19r>8 Inventory of Municipal Waste Facilities in the United States
TABLE 10
-------
population served. This number is then taken as the average
construction cost per capita. Average per capita construction
cost estimates computed in this way are shown in Tables 11 and
12. Notice that various distributions according to size have
been used. Values shown in Tables 11 and 12 must be multiplied
by the appropriate excess capacity factor (average value = 1.5)
to find the true per capita construction cost. Construction
cost relationships from Table 3 were used to compute the values
shown in Table 11. Relationships from Table 4 were used to
compute average per capita cost shown in Table 12.
A similar procedure, but omitting the 1.5 factor, was used for
computing the average operating and maintenance cost in dollars/
capita/year. These are shown in Tables 13 and 14.
As pointed out earlier, the per capita construction cost for
sewers is a function of the population density as shown in
Figure 8. The population density is shown to depend on the size
of the community in Figure 9. The procedure for computing the
national average per capita sewer construction cost is as follows;
For each population size group divide the number of inhabitants
served by the number of communities to find the average size
community in the population size group. From the average size
community find the population density in persons/acre. With this
value of population density find the sewer construction cost per
capita. Multiply the per capita cost by the total number of
inhabitants in the population size group to find the total con-
struction cost for the group. Repeat the procedure for each
population size group and sum over all groups. Divide
the summed cost by the total number of sewered inhabitants
to find the national average per capita sewer construction cost.
The details of this computation are shown in Table 15. The
average per capita cost using the total sewered population from
the 1968 Inventory of Municipal Waste Treatment Facilities (!)
was found to be $157.82.
The linear feet of sewer per capita can be shown to depend on the
population density in the following way:
Feed of Installed Sewer/capita = 54 (persons/acre)"
Using the total sewered population distribution, a method similar
to the one described above was used to find the national average
linear feet of sewer per capita. The computed value was 14.28
feet/capita. Details of this computation are shown in Table 16.
In a study of waterworks made in 1955, Seidel and Baumann(22)
found the average length of water main per 1000 population to be
2.6 miles which corresponds to 13.73 feet per capita.
43
-------
Type of Treatment
3
XI
a.
Total Sewered
Populati on
Activated Sludge
and Extended
Aeration
Tr icklinq
Filter
Primary
Sedimentat ion
Stabilization
Ponds
Act i vated
Sludye
2H.95
25.53
s s
I ntercepto
and OutJ'al
29.H3
29.49
c'
X. H
U *J
F- U.
29.40
45.14
c
Pr imary
Sedimentat i
17.71
,...„,
E
0
u
Upgrading I
Primary to
Act i vated
Sludge
17.49
15. 10
c
N
'i C
»J 0
CO G.
5.23
21.42
NATIONWIDE AVERAGE CONSTRUCTION COST, DOLLARS PER CAPITA (19o8 DOLLARS)
Source: cost data - R. L. Michel, Construction Grants and Engineering Branch, FWQA
population distributions - 1968 Inventory of Municipal Waste Facilities in the U. S.
TABLE 11
-------
Type of Treatment
Ul
r.
Q
Total Sewered
Population
Activated Sludge
and Extended
Ae ration
TricklI:i.T
Filter
Primary
Sedimentation
^j
' 41 -
> ^>
•- TJ
'J r-1
<
:4.55
32.43
_=
i-H Li
X 11
1-1 -H
t-c £1.
31.87
4-i.l5
c
>> c
LI i)
' E
E — '
v- "y
Ci. in
20.04
18.51
NATIONWIDE AVEi-^AGE CONSTRUCTION COST, DOLLARS PE.^ CAPITA (19^8 DOLLARS)
Source: rest data - Xobert Smith, "Cost or Conventional and Advanced Treatment 01" Wastewaters'
population dir-tributions - l>-i:8 Inventory of Municipal Waste Facilities in the U. S.
TABLE 12
-------
Type of Treatment
Total Sewered
Poulation
c Activated Sludge
•H and Extended
3 Aeration
a
2 Trickling
Q Filter
c
0
•H
4J
£ Primary
3 Sedimentation
u.
0
Q.
Stabilization
Ponds
•o
01
+•>
l|
•M 3
U iH
< Ifl
2.03
1.87
_,
c
•-^
r-l kl
-i: oi
y •-•
•H •-<
14 -H
(-C li.
1.23
1.94
B
0
.•)
> C
I!
•H 13
u 01
0. (/)
1.41
1.32
c
0
«
N
•H J)
j -a
-------
Type of Treatment
Total Sewered
Population
Activated Sludge
and Extended
Aeration
Trickling
Filter
Primary
Sedimentation
•0
0)
> D>
•H -O
•P 3
< (A
2.13
1.96
m
c
•H
•H VI
^ (V
O *>
•rl r-(
H -H
H U.
1.39
2.17
C
0
•H
*->
Ifl
4J
X C
3 s
S -rl
•H -0
n oi
a.
-------
CONSTRUCT I J,g COST FOR SEWEkS
B4SED Ov 1968 SE-EREC PoPULATIC'-
co
\OMHER OF PLiNiTS f
1 791 .
2259.
5375.
1 5 1 * .
1200.
422.
203.
145.
COPULATION SERVED
693874.
1828753.
12385893.
9570149.
15504150.
12697700.
13421 17b.
741259J5.
TOTAL POPULATION 140227529.
TOTAL CAPITAL CCST 22130916624.
AvtkAot PtR CAPITA COST i.57.t3J
CLST INDEX i.oooo
POPULATION PER PL4NT
3b7.
809.
2304.
^312.
12920.
30089.
661 14.
511212.
CAPITA CIST,
499.51
41^.89
320. 1 7
258.81
216.62
1 M.14
91.91
TABLE 15
-------
PER CAPITA LENGTH OF SEWERS IN THE UNITED STATES
Number of
Communities
1,791
2,259
5,375
1,516
1,200
422
203
145
BASED ON
Population
Served
693,874
1,828,753
12,385,893
9,570,149
15,504,150
12,697,700
13,421,175
74,125,835
1968 SEWERED POPULATION
Average Population
Per Community
387
809
2,304
6,312
12,920
30,089
66,114
511,212
Length of Sewer,
ft/capita
36.93
32.10
26.32
21.73
18.96
16.15
13.91
9.43
Total Population 140,227,529
Total Length of Sewers, ft. 2,003,368,843
Average Length of Sewer, ft/capita 14.28
TABLE Id
-------
The yearly charge for Customer Service and Accounting and for
General and Administrative Cost were both shown (Figures 10
and 11) to depend on the size of community. A method similar
to that described above was used to compute the national
average cost of these two services. For Customer Service and
Accounting the national average cost was found to be $0.71
per capita per year. For General and Administrative cost the
national average was computed as $1.37 per capita per year.
The national average per capita cost for tertiary treatment
processes was computed in the same way using the total sewered
population size distribution. These computed per capita costs
are shown in Table 17. Again an excess capacity multiplier
(average = 1.5) must be used to find the true per capita cost
for construction.
50
-------
NATIONWIDE AVERAGE CONSTRUCTION AND OPERATING AND MAINTENANCE COST
FOR TERTIARY WASTEWATER TREAT NENT PROCESSES
(based on 1968 dollars and plants of
one mgd or larger in the United States)*
Construction Cost, Operating and Maintenance
$/capita Cost, $/yr/capita
Microscreening 2.O7 .17
Filtration 3.20 .58
Two-Stage
Lime Clarification 5.97 .97
Lime Recalcination 4.72 .86
Ammonia Stripping 6.37 .79
Carbon Adsorption 14.36 2.95
Two-Stage
Lime Clarification
with Disposal or
Recalcination • 1.96
Two-Stage
Lime Clarification
and Filtration 9.17 1.55
Two-Stage
Lime Clarification
and Ammonia Stripping 12.34 1.76
Two-Stage
Lime Clarification
and Ammonia Stripping
and Carbon Adsorption 26.70 4.71
* Total Sewered Population from 1968 Inventory of Municipal Waste
Treatment Facilities Used. 1.5 Excess Capacity Factor Used for
Construction.
TABLE 17
51
-------
COST OF INDUSTRIAL WASTEWATER TREATMENT
The 1968 Cost of Clean Water(2) report estimated the cost of
achieving adequate wastewater treatment in the industrial
sector using two separate methods. The first method made use
of the 1964 Census of Manufacturers(23) issued by the Bureau
of Census. The second method used data presented in the
Industrial Waste Profiles reported in the ten sections of
Volume III of the 1968 Cost of Clean Water(2) report.
The 1964 Census of Manufacturers listed water use and wastewater
production for two classes of manufacturing industry; those
using under 20 million gallons per year (smaller users) and those
using more than 20 million gallons per year (larger users). The
authors of the 1968 Cost of Clean Water(2) report assumed that
all of the wastewater from the smaller users would be discharged
to public sewers and the cost of treating this industrial waste
was lumped with the municipal cost. A small fraction (about 10%)
of the water from the larger users was also known to be discharged
to municipal sewers. Cost estimates given for industrial treat-
ment refer only to that fraction of the wastewater from larger
users which is not discharged to public sewers.
The amount of water discharged to public sewers by the smaller
industrial users in 1968 was estimated as 310 billion gallons/yr.
The amount of water discharged to the public sewers by the larger
users was estimated as 1,029 billion gallons/yr in 1968 and 1,157
billion gallons in 1973. The sewered population in the United
States in 1968 was 140.226 million. Estimating the per capita
use exclusive of manufacturing as 120 gallons/day/capita the
total sewage volume would be 16.83 billion gallons/day or 6,142
billion gallons/yr. On a volume basis the contribution of manu-
facturing to public sewers is about 22 percent of the total
sewered waste which is equivalent to about 26 gallons per day
per capita.
Water produced by the larger users (over 20 million gallons/yr)
in 1964 was estimated by the Census of Manufacturers as 13,157
billion gallons/yr. Nine-hundred eighty seven billion gallons/yr
was discharged to public sewers leaving 12,17O billion gallons/yr
to be treated at the plant or discharged without treatment. The
largest fraction of this, 9,385 billion gallons/yr, is represented
by cooling water which needs either minimal treatment or no
treatment.
53
-------
About 3,703 billion gallons/yr are used as process water. The
BOD and suspended solids concentration of process water far
exceeds that of normal raw sewage. A comparison of the pollutional
load contributed by process water as compared with normal sewage
is shown in Table 18. Industrial wastewater is, therefore, greater
in volume and pollutional load than municipal sewage.
The first cost estimation method used the 1964 Census of Manufacturers
for estimating the quantity of wastewater discharged and used the
cost of municipal sewage facilities to represent the cost of
industrial wastewater treatment. The assumed removal of contaminants
associated with industrial treatment was 85 percent removal of
both 5-day BOD and suspended solids. The second method of cost
estimation used the Industrial Waste Profiles published in ten
sections of Volume III of the 1968 Cost of Clean Water(2) report.
This method appears to be the most reliable and also gives the
least estimate of the investment expenditures needed. Cost
estimates derived using both methods are shown in Table 19, taken
from the 1968 Cost of Clean Water report. An annual expenditure
between 400 to 600 million dollars was believed to be needed to
overcome the deficiency in industrial treatment over the five-
year, 1969-73, period. This sum represents about l5g percent of
the approximately $30 billion annual budget for new plant and
equipment expenditures in the manufacturing sector.
The same two methods were used in the 1968 Cost of Clean Water(2)
report to estimate the annual operating and maintenance cost for
industrial wastewater treatment plants. These are shown in Table
20. Over the six-year period the annual operating and maintenance
cost averaged about $600 million per year. If we add about $450
million for new plants, the yearly average expenditures for
industrial treatment over the five-year period is about 1.O5
billion dollars per year. The population of the United States in
1968 was about 200 million and will increase to about 216 million
by 1973. Assuming that the entire population pays for industrial
wastewater treatment in the form of higher cost for manufactured
goods, the average total per capita cost would be about $5.50
per capita/year.
54
-------
ESTIMATED VOLUME OF INDUSTRIAL WASTES
Ui
Ln
Industry
Food and Kindred Products
Meat Products
Dairy Products
Canned and Frozen Food
Sugar Refining
All Other
Textile Mill Products
Paper and Allied Products
Chemical and Allied Products
Petroleum and Coal
Rubber and Plastics
Primary Metals
Blast Furnaces and Steel Mills
All Other
Machinery
Electrical Machinery
Transportation Equipment
All Other Manufacturing
All Manufacturing
For comparison:
Sewered Population of U. S.
: TREATMENT, 1
Waste-
water
Volume
(Billion
Gallons )
690
99
58
87
220
220
140
1,9OO
3,700
1,300
16O
4,300
3,600
740
150
91
24O
450
13,100
2/
5,300—
Intake
(Billion
Gallons)
260
52
13
51
110
43
110
1,300
560
8fl
19
1,OOO
870
130
23
28
58
190
3,700
Process Water
BOD 5
(Million
Pounds )
4,300
640
400
1,2OO
1,4OO
670
890
5,900
9.70O
5OO
40
480
160
320
60
7O
120
390
22,000
3/
7,3OO—
Suspended
Solids
(Million
Pounds )
6,600
04O
230
6OO
5.0OO
110
N. E.
3,000
1,900
460
5O
4,700
4,300
430
50
20
N. E.
930
18,000
4/
8 , 8OO-
I/ Columns may not add, due to rounding
2/ 120,000,000 persons x 120 gallons x 365 days
3/ 120,OOO,OOO persons x 1/6 pounds x 365 days
£/ 120,OOO,000 persons x 0.2 pounds x 365 days
TABLE 18
-------
ANNUAL INVESTMENT REQUIRED TO REDUCE THE EXISTING INDUSTRIAL
WASTE TREATMENT DEFICIENCY _IN FIVE YEARS
(Wastewatcr Profiles and Estimates)
Millions of 1968 Dollars
un
Industry
Food and Kindred Products
Meat Products
Dairy Products
Canned and Frozen Foods
Sugar Refining
All Other
Textile Mill Products
Paper and Allied Products
Chemical and Allied Products
Petroleum and Coal
Rubber and Plastics, n.e.c.
Primary Metals
Blast Furnaces and Steel Mills
All Other
Machinery
Electrical Machinery
Transportation Equipment
All Other Manufacturing
All Manufactures:
By Wastewater Profiles and Estimates
(By Census-Municipal Projections)
Annual Investment Total Investment to Reduce Waste
To Reduce Existing Treatment Requirements and Meet
Requirement Growth Needs
43.9
7.0
4.6
6. 7
13.5
12.1
5.3
15.1
56.0
15.4
6.2
29.9
19.6
10.3
5.0
1.7
8.3
23.5
210.3
(528.5)
1969
63.2
10.1
5.1
11.4
19.3
17.3
9.8
19.1
75.7
15.4
7.0
83.6
52.4
31.2
6.9
3.6
11.7
32.3
328.3
(676.9)
1970
65.4
11.2
5.7
12.4
18.4
17.7
10.9
25.5
76.9
18.1
7.9
91.3
59.1
32.2
6.9
3.8
11.9
32.6
351.2
(705.8)
1971
69.9
11.2
5.5
12.6
22.6
18.0
11.1
26.0
77.7
30.5
7.1
93.3
60.1
33.2
7.1
3.8
12.2
33.0
371.7
(731.5)
1972
70.0
11.7
5.5
12.9
21.4
18.5
11.0
26.4
79.4
31.7
7.2
96.2
63.0
34.2
7.1
4.0
12.1
33.5
378.6
(740.2)
1973
69.9
11.6
5.5
13.0
21.5
18.3
11.6
27.0
77.9
32.1
7.1
97.8
63.0
34.8
7.3
4.1
12.3
33.8
380.9
( 743 . 1
TABLE 19
-------
ANNU/ DERATING AND MAINTENANCE COSTS
Industry
Food and Kindred Products
Meat Products
Dairy Products
Canned and Frozen Foods
Sugar Refining
All Other
Textile Mill Products
Paper and Allied Products
Chemical and Allied Products
Petroleum and Coal
Rubber and Plastics, n.e.c.
Primary Metals
Blast Furnaces and Steel Mills
All Other
Machinery
Electrical Machinery
Transportation Equipment
All Other Manufacturing
All Manufacturers:
By Wastewater Profiles and Estimates
By Census-Municipal Projections
1968-1973
Annual Operating and Maintenance Costs
(Millions of 1968 Dollars)
1968
85.4
15.3
16.1
17.9
19.1
17.0
39.0
33.3
21.1
60.5
1.8
137.8
90.1
47.7
2,5
4.8
29.4
15.3
430.9
(348.7)
1969
95.9
16.4
17.1
19.9
22.5
20.0
41.7
35,9
T 7 . 2
63. b
3,0
146. 5
95.5
51.0
3,7
5 , 5
31. 4
21.0
485.4
(453.5)
1970
107.0
17.7
18.3
22.0
25.8
23.2
44.8
39.3
53.5
67.7
4.4
155.9
101.6
54.3
4.9
6. 1
33.4
26,8
543 . 3
(565.t>)
1971
118.7
19.0
19.4
24.2
29.8
26.3
47,9
42.8
70 . < )
73.3
5. 7
165.7
107.9
57.8
t> . 2
6.8
35,5
32.6
605, 2
(679.9)
1972
130.4
20. 3
20.5
26.5
33.5
29.6
51. 0
46.4
86.8
79.6
7.0
175.7
114.4
61.3
7.5
7.5
37.5
38.5
667.9
(802.1)
1973
142.1
21.6
21.6
28.7
37.3
32.9
54.3
50.0
103.3
86.1
8.2
185.9
121.0
64.9
8.7
8.2
39.6
44. 5
73O.9
(921.7
TABLE 2O
-------
EVALUATION OF THE TREATMENT BACKLOG
The magnitude of the backlog in construction of treatment facilities
is shown in Figure 4. The FWQA target has been to overcome this
backlog by 1973. Using 1968 as the base year the cost of constructing
the additional needed treatment facilities can be computed by
first noting that the projected urban population for 1973 is about
165.2 million persons. Inventories of Municipal Waste Treatment
Facilities for 1957, 1962, and 1968(4)'(6)'t1' are summarized in
Table 21. From Table 21 it can be seen that in 1968 a total of
69.979 million persons were served by adequate secondary treatment.
It will be assumed that those served by primary sedimentation and
intermediate treatment can be adequately served by upgrading the
present facilities to activated sludge treatment. This population
numbers 36.377 million with primary sedimentation and 5.858 million
with intermediate treatment making a total of 42.235 million to
be upgraded.
Subtracting these two totals from the 165.2 million estimated 1973
urban population gives a total of 52.986 million for which new
activated sludge plants plus interceptors and outfalls will be
needed by 1973. The cost of this new construction of activated
sludge plants in terms of 1968 dollars is computed as follows:
52.986 million x 1.5 x ($28.95 + $29.88) = $4.676 billion. The
cost of upgrading the primary and intermediate plants can be
calculated as follows: 42.213 million x 1.5 x $17.49 = $1.107
billion.
An allowance for depreciation of installed treatment facilities
must be added to the cost of new construction. The replacement
cost of the treatment plants and ancillary works will be taken
as the average replacement cost obtained by averaging the
replacement value in 1968 with the replacement value in 1973.
The value of installed structures in 1973 will be approximated
by the value of activated sludge plants and ancillary works for
the total urban population. This can be computed as follows:
165.2 million x 1.5 x ($28.95 + $29.88) = $14.578 billion.
The replacement value of plants and ancillary works in 1968 is
computed as shown in Table 22. The total replacement value of
treatment works in 1968 is approximately $10.599 billion. The
average value of structure over the five-year period will,
therefore, be 12.589 billion dollars. The useful life of plants
will be taken as 25 years and the useful life of ancillary works
as 50 years. Since the cost of activated sludge plants about
59
-------
SUMMARY OF WASTEWATER COLLECTION AND TREATMENT IN UNITED STATES
1957 - 1968 (Population in Millions)
1957 1962 1968
TOTAL SEWERED POPULATION 98.361 118.372 14O.226
Total Treated 76.443 103.685 130.685
Discharging Raw 21.917 14.687 9.541
TOTAL TREATED 76.443 103.685 13O.685
Minor 1.86O 2.351 1.361
Primary 25.667 32.733 36.947
Intermediate 5.591 7.4O9 5.858
Secondary 43.326 61.191 83.64O
Tertiary O.OOO O.OOO O.326
PRIMARY TREATMENT
Septic Tanks O.987 O.681 0.569
Sedimentation 24.680 32.O52 36.377
ADEQUATE SECONDARY TREATMENT
Activated Sludge 24.754 33.287 38.542
Standard Rate Trickling Filter 9.351 11.532 11.979
High Rate Trickling Filter 5.963 11.473 16.433
Extended Aeration O.OOO O.4O6 2.705
4O.O68 56.698 69.659
WASTE STABILIZATION PONDS O.76O 2.195 6.O91
INTERMITTENT SAND FILTER O.332
APPLICATION TO LAND O.413
OTHERS AND UNKNOWN 9.O9O
TERTIARY TREATMENT .326
Source: Inventory of Municipal Waste Facilities in United
States
TABLE 21
60
-------
ROUGH CALCULATION OF INVESTMENT IN SEWAGE TREATMENT FACILITIES
1.
2.
3.
4.
5.
AND ANCILLARY WORKS IN
Activated Sludge, Extended Aeration
and Tertiary Treatment Plants
Primary Sedimentation and Intermediate
Treatment Plants
Trickling Filter Plants
Stabilization Ponds
Total
Interceptor Sewers and Outfalls
THE UNITED STATES
Population
Served
41.567 mil.
42.805 rail.
28.412 mil.
6.091 mil.
118.875 mil.
130.685 mil.
IN 1968
Unit Cost
per PE*
$25.53
$16.04
$45.14
$21.42
$29.88
Capital Cost**
Billions of Dollars
$1.592
$1.030
$1.924
$.196
$4.742
$5.857
$10.599
* Population Equivalent
** Design population taken as 1.5 times the population served
Total Investment = $11.069 Billion
Average Treatment Plant Cost per PE = $26.59
TABLE 22
-------
equals the cost of ancillary works, the depreciation rates of 496
and 2% will be averaged to give an overall rate of 3%. The cost
of depreciation will, therefore, be 377.67 million dollars per
year or a total of $1.888 billion for the five-year period.
Summing the cost of new activated sludge plants ($4.676 billion),
upgrading primary and intermediate plants ($1,107 billion) and
providing for depreciation ($1.888 billion), the total cost of
overcoming the backlog is $7.671 billion in terms of 1968 dollars,
The 1968 Cost of Clean Water(2) report estimated this cost of
overcoming the backlog of municipal construction as'$8 billion
in 1968 dollars.
The cost of constructing treatment works has been inflating at a
rate between 6% and 6.5% over the last two years. Using a 6%
inflationary estimate the $7.671 figure must be multiplied by a
factor of 1.1274 to give a total of $8.648 billion in current
dollars.
The third report of the series known as the Cost of Clean Water
Series was issued in March 1970. This report entitled The
Economics of Clean Water(^4) reported the results of a very
detailed study of the investment backlog in municipal treatment
works. The backlog as of 1969 was computed as $4.4 billion.
The required investment for the 1970-74 period was conservatively
estimated as $10 billion in current dollars.
62
-------
FULL COST OF COLLECTION AND TREATMENT
Expenditures for sewage collection and treatment are of two basic
kinds; capital outlay for land, equipment, and structures, and
current expenses such as labor, chemicals, and supplies. To
compute the total cost of sewage collection and treatment these
two kinds of expenses must be equated. This can be done in two
ways. All expenses can be expressed either on a continuous cash
flow basis or on a present value basis. These concepts are
discussed fully in Chapter 5 of Plant Design and Economics for
Chemical Engineers by Peters and Timmerhaus
The full cost of sewage collection and treatment will be computed
here on a continuous cash flow basis. The treatment plant will
be amortized over a 25-year period and the collection system will
be amortized over a 50-year period. The cost of borrowing money
will be taken as 5 percent. The cost of land for the plant site
is not included because of the strong dependency on the area of
the country and topographical considerations.
The capital investment in existing treatment plants for the year
1968 is computed in Table 22 based on the 1968 Inventory of
Municipal Waste Facilities and the construction cost relationships
developed by R. L. Michel of Construction Grants and Engineering
Branch of FWQA. Cost estimates for some minor processes are not
available, and the specific type of treatment is not known for
more than nine million population. The average capital cost per
population equivalent for the processes shown in Table 22 is
$26.59/capita. Multiplying this by the total treated population
of 130.685 million and the factor 1.5 gives the total investment
in treatment plants of $5.213 billion. The investment in
ancillary works (interceptors and outfalls) is $29.88 x 1.5
x 130.685 or 5.857 billion dollars. The amortization factor
of 0.07095 corresponding to 25 years and 5 percent interest was
used to compute an amortization charge for the treatment plant of
$2.83/capita/year. The amortization charge for ancillary works
using an amortization factor of 0.05478 corresponding to 5
percent and 50 years was computed as $2.46/capita/year .
A computation of the average per capita cost for operation and
maintenance of treatment plants based on the 1968 Inventory is
shown in Table 23. The limits of $1.63 and $1.47 were averaged
to give $1.55/capita/year for operation and maintenance plants.
63
-------
COMPUTATION OF NATIONAL AVERAGE
OPERATION AND MAINTENANCE COST FOR TREATMENT PLANTS
(19fc>8 dollars)
Activated Sludge and
Extended Aeration
Primary Sedimentation
and Intermediate
Trickling Filters
Stabilization Ponds
Total
c
0
•H
•fj
rt
r-t
3
a
0
a.
.
i— i
•H
e
r-
T3
0)
V-f
U
to
+-*
t/)
3
rH
fd
d
c
c
•5
«j
• H
a
nJ
0
L_(
QJ
a
•o
c
rt
0
•H
4_>
fd
M
<1>
p^
o
CJ
o
c
0)
c
•H
rt
•
i_(
^
"\
•fj
'n
O
U
41.247
$1.87
$77.1.32 mil,
42.235 $1.32 $55.75O rail,
28.412 $1.94 $55.119 rail,
6.O91 $0.67 $4.O81 rail,
117.985 $192.082 mil,
1. Average Operation and Maintenance Cost - $1.63/capita/yr.
2. Average Operation and Maintenance Cost = $192.082 mil./
130.685 mil. = $1.47
Source of Cost Data: R. L. Michel, Construction Grants and
Engineering Branch, FWQA
TABLE 23
64
-------
American Public Works Association estimated the cost of the
house connection as $81.51 per house. This corresponds to
60 feet of 6-inch vitrified clay pipe. Amortization cost for
the house connection, assuming 3.23 persons per household is
$1.38 per capita per year. The cost of constructing municipal
sewers has been shown in Table 24 to average $157.82 per capita.
Using the amortization factor for 50 years and 5 percent, the
yearly amortization cost for municipal sewers was computed as
$8.64/capita/year.
The average cost of maintaining municipal sewers was taken as
6 cents per linear foot per year. The average length of sewer
was computed to be 14.28 feet/capita. The average yearly cost
of sewer maintenance is, therefore, 86 cents/capita/year.
The average charge for customer service and accounting was
computed as 71 cents/capita/year. The general and administrative
cost was computed as $1.37 per capita per year.
The total cost of collection and treatment based on the treatment
level prevailing in 1968 is shown in Table 24.
On a per capita basis the total cost shown in Table 24 would change
only slightly if the whole nation was equipped with activated
sludge treatment. For example, the amortization cost for the
plant would be $3.08/capita/year instead of $2.83 and the operation
and maintenance cost for the plant would be $2.03 instead of
$1.55. The total increase in cost would, therefore, be 73 cents/
capita/year which is only about 3.7 percent of the total cost.
Current expenditures, revenue from user charges, and capital
outlay data have been collected by the Bureau of Census for
various governmental units in the United States. Data for the
Nation as a whole is shown in Table 25. Current expenditures
include operating and maintenance for the treatment plant, sewer
maintenance, billing and collection, and miscellaneous adminis-
tration including engineering.
The capital outlay for sewerage works and for water supply facilities
is shown in Figure 12. From Table 25 it can be seen that the
reported current expenditures for sewage collection and treatment
is only about 10 to 15 percent higher than the revenue collected
in user charges.
The total population with treatment facilities in 1968 was
13O.685 million. If we assume that only the treated population
paid user charges, the 534 million dollar figure can be divided
by 130.685 to give an average user charge of $4.09. The average
.expenditure for sewerage services using the same assumption is
625/130.685 = $4.77- The average expenditure is close to the
estimate of $4.49/capita/year.
65
-------
TOTAL COST OF SEWAGE COLLECTION AND TREATMENT Ij< 1968
ON A CONTINUOUS CASH FLOW BASIS
1968 dollars/capita/year
Amortization Cost
House Connection $1.38
Municipal Sewers $8.64
Interceptors and Outfalls $2.46
Treatment Plants $2.83
Total Amortization Cost $15.31
Current Expenses
Municipal Sewer Maintenance $O.86
Treatment Operation and $1.55
Maintenance
Customer Service and Accounting $O.71
General and Administrative $1.37
Total Current Expenses $4.49
Total Cost of Municipal Collection $19.8O
and Treatment
TABLE 24
66
-------
EXPENDITURES FOR SEWERAGE COLLECTION AND TREATMENT
Year
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
1958
1957
IJN THE
(millions
Sewer
Charges
534
571
571
519
468
470
386
33O
318
266
226
219
UNITED STATES
of current dollars)
Sewer
Current
Expenditure
625
626
5O5
462
420
407
386
377
336
303
284
262
Capital
Outlay
1,107
1,069
1,202
1,107
1,095
1,057
886
726
767
708
649
644
TABLE 25
67
-------
rt
(V
I/)
U
nj
•8
O
rt
+J
•H
a
12OO
11OO
1OOO
9OO
HOO
7OO
600
500
4OO
3OO
2OO
1OO
0
CAPITAL OUTLAY FOR NEW SEWAGE COLLECTION
AND TREATMENT FACILITIES
IN
CURRENT DOLLARS
Sewage Treatment Facilities
Water Treatment Facilities
1952 54 56 58 60 62 64 66 08 7O 72
Year
FIGURE 12
68
-------
Among the conclusions which can be drawn from Table 24 are first,
that the current expenses associated with collection and treatment
are only about 23 percent of the total cost for domestic sewage
collection and treatment and second, that the cost of constructing
sewers is about three times the cost of constructing treatment
plants. This conclusion does not change appreciably if activated
sludge secondary treatment is assumed.
The house connection is normally paid for by the house owner as
part of the purchase price for the house. The cost of constructing
municipal sewers is paid for either as an assessment or as part of
the purchase price for the house. In some instances grants-in-aid
are provided by the Federal Government to finance sewerage systems
in rural areas. The cost to the rural municipality in this case,
would be about $9.78/capita/day of which about 40 percent is
paid for in user charges. The remainder is paid for in the form
of taxes primarily at the local level.
The cost of tertiary treatment can now be examined using the
values shown in Table 17 as a background. Again amortizing the
construction cost over 25 years at 5 percent interest, the cost
of microscreening for removing particulate organic matter which
escapes the final clarifier would amount to about 33 cents/capita/
year.
69
-------
GOVERNMENTAL EXPENDITURE FOR GRANTS-IN-AID
Treatment plants, interceptor sewers, and outfalls are normally
financed by selling municipal general obligation bonds which
are paid back out of general revenue from taxes. Part of the
capital outlay for these facilities is supplied in the form
of grants-in-aid from Federal and State Governments. The princi-
pal source of grants-in-aid for treatment plants, interceptors
and outfalls is the Federal Water Quality Administration. The
amount of these grants-in-aid for construction are shown in Table
26. Other Federal governmental agencies supply lesser amounts
of grants-in-aid. For example, the Economic Development
Administration of the Dept. of Commerce expended $5,307,000
during fiscal year 1969 for sewerage works. For the four-year
period, 1966-69, a total of $44,868,000 was expended by EDA
for sewage works. The Dept. of Commerce also administers the
Appalachian Regional Development Act. Under the terms of this
law a total of $7,309,000 was expended for sewerage works
grants-in-aid in the six-year period, 1965-70. The Farmer's
Home Administration makes grants-in-aid primarily for construction
of new sewers. The total expenditure during fiscal year 1970
for water supply and sewers was about $42 million of -"hich about
$20 million was used for new sewer construction. The Department
of Housing and Urban Development also makes grants-in-aid for
sewage works and water supply. Expenditure for sewage collection
and treatment facilities totaled $228 million over the four-year
period, 1966-69. Of the $228 million, 92.5% was spent, on new
sewers.
Federal Water Quality Administration is authori2ed by Congress to
contribute up to 30 per cent of the construction cost of treatment
plants, interceptor sewers, and outfalls if the State government
makes no contribution. FWQA can increase the federal contribution
to 55% of the construction cost if the State government will
provide at least 25% of the cost.
In 1967 only seven states authorized the expenditure of inter-
governmental funds for construction of sewage treatment facilities.
The amount of money appropriated or authorized together with the
actual expenditure for construction is shown for all seven states
in Table 27. The total for authorized funds was $14.5 million
but the amount actually expended is not known. The total amount
of public construction in 1967 was $1,069 million for sewers and
treatment plants. In 1967 grants-in-aid from the federal government
amounted to about $154 million. States contributed a maximum of
$14.4 million for a total of $168.4 million. This represents about
15.7% of the capital outlay for construction in 1967.
71
-------
CONSTRUCTION GRANTS FOR CONSTRUCTION OF
WASTE TREATMENT WORKS ADMINISTERED BY FWQA
1963 $93,349,000
1964 $66,432,000
1965 $69,755,000
1966 $81,479,000
1967 $84,476,OOO
1968 $122,1O7,OOO
1969 $202,517,660
1970 $514,840,867
Proposed Expenditure
1971 1 Billion Dollars
1972 1 Billion Dollars
1973 1 Billion Dollars
1974 1 Billion Dollars
TABLE 26
72
-------
STATE GRAINS-IN-AID FDR SEWERS AND SEWAGE TREATMENT PLANTS
(19&7)
Delaware
Cities
Maine
Maryland
Cities
Counties
Specia] Districts
New Hampshire
Cities
New Jersey
Cities and
Special Districts
New York
Cities
Counties
Towns
Vermont
Total
Appropriated or
Authorized funds
$263,000
$678,OOO
$304,000
$1,435,000
$79,000
$997,000
$3,464,000
$414,000
$5,6OO,OOO
$264,000
$H51,000
$14,349,000
Capital Outlay
For Sewage Facilities
$2,695,000
$679,000
$3,691,000
$1 ,194,OO()
$12 , 3H'J ,OOO
$51,755,000
$1.118.OOP
$7'3, 51 5, OIK.)
Source: U.S. Bureau of Census, Census of Governments, 1967, Vol. 6,
No. 4, State Payments to Local Governments, U.S. Government
Printing Office, Washington, D.C., 196H.
TABLE 27
73
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A more recent analysis of the grants-in-aid program was presented
in the FWQA report, The Economics of Clean Water(24). The
federal share of all waste-handling cost was placed at 18% which
is about the same as the overall level of federal assistance to
local governments for all purposes.
74
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COST COMPARISON BETWEEN COLLECTION AND TREATMENT, RELATED SERVICES
AND PERSONAL CONSUMPTION EXPENDITURE
Even though the benefits associated with sewage treatment are
difficult to evaluate in terms of dollars, the true cost of
owning and operating collection and treatment facilities can be
estimated with adequate precision. Expenditure for other
personal consumption categories and governmental activities is
available from the work of the Bureau of Census(26)>(27). A
comparison of the cost of municipal and industrial wastewater
collection and treatment with other categories of spending will
be made here in an effort to show the general magnitude of the
problem.
The national product of the United States is shown in Figure 13
for the years 1959-69. The gross national product is approaching
one trillion dollars. About 62% of this potential buying power
is spent on personal consumption expenditures. These are
itemized for the years 1965-68 in Table 28. Spending for water
and sewerage services represents the total paid user charges
which, in 1967, was given as 1.97 billion dollars.
Other more detailed cost data gathered by the Bureau of Census
and shown in Table 25 and 29 show the total amount paid by
consumers for water and sewerage services to be 2.76 billion
dollars in 1967- This larger estimate represents about 0.56%
of the total personal consumption expenditures.
The amount paid by consumers in 1967 for water supply was
2.187 billion dollars or about 0.44% of total personal consumption
expenditures. The amount paid for sewerage services was 0.571
billion dollars, about 0.116% of the total, which is about 1/9
that paid for toilet articles.
The number of persons served by potable water supplies in 1967
was about 163 million. Dividing the total revenue (2187 mil.)
by the population gives about $13.42/capita/year paid for water
supplies. The total cost of supplying potable water was
investigated in 1955 by Seidel and Baumann(22). The delivery
cost per 1000 cu. ft. was found to vary from $3.21 to $2.02
with an overall average of $2.75. This average cost corresponded
to plants in the range of 2-6 mgd. Using the consumer price
index for water and sewerage services the $2.75 cost corresponds
to a 1967 cost of $4.10 per 10OO cu. ft. or 54.7 cents/1000
gallons. The same report by Seidel and Buamann showed that the
75
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1OOO
80O
600
i
&
I 400
200
Gross National Product
Personal Consumption Expenditures
1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970
Year
DISPOSITION OF NATIONAL PRODUCT IN THE UNITED STATES
Source: U. S. Department of Commerce 1969 Business Statistics
FIGURE 13
76
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PERSONAL CONSUMPTION EXPENDITURE BY_ TYPE OF PRODUCT
(Millions
of dollars )
1965 1966
FOOD AND TOBACCO 107,183
CLOTHING, ACCESSORIES, AND 43,318
JEWELRY
PERSONAL CARE
1. Toilet articles and
preparations (n.d.c. )
2. Barbershops, beauty parlors,
and baths (s . )
HOUSING
HOUSEHOLD OPERATION
1. Furniture, including
mattresses and bedsprings
(d.c.)
2. Kitchen and other household
appliances (d.c. )
3. China, glassware, tableware,
and utensils (d.c. )
4. Other durable house
furnishings (d.c. )
5. Semidurable house furnishings
(n.d.c. )
6. Cleaning and polishing prep-
arations, and miscellaneous
household supplies and
paper products (n.d.c. )
7. Stationary and writing
8. Household utilities
a. Electricity(s . )
b. Gas (s .)
c. Water and other
sanitary services(s.)
d. Other fuel and ice(n.d.c.)
9. Telephone and telegraph(s . )
10. Domestic service (s.)
11. Other(s.)
MEDICAL CARE EXPENSES
PERSONAL BUSINESS
TRANSPORTATION
7,578
4,211
3,367
6.3 , 509
61,789
6,254
6,026
2,526
6,119
4,169
4,261
1,434
17,845
6,6O8
4,075
1,771
5,391
6,423
3,964
2,768
28,O82
21,879
58,154
114,621
48,360
8,068
4,543
3,525
67,506
66,786
6,826
6,766
2,776
6,650
4,696
4,560
1,646
18,912
7,027
4,242
1,873
5,770
6,905
4,028
3,021
31, 142
24,287
60,489
1967
117,395
51,054
8,578
4,877
3,701
71,8O6
70 , 498
7,033
7,087
2,900
6,915
4,970
4,684
1,769
19,900
7,493
4,432
1,972
6,003
7,532
4,444
3,264
34,647
26,226
62,844
1968
124,694
55,460
9,110
5,261
3,849
77,4O9
75,919
7,460
7,8O1
3,245
7,839
5,464
4,899
1,879
20,950
8,131
4,588
2.068
6,163
8,14O
4,638
3,604
38,580
29,593
72,220
TABLE 28
77
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PERSONAL CONSUMPTION EXPENDITURE BY TYPE OF PRODUCT
(Millions of dollars)
[Continued]
RECREATION
1. Books and raaps(d.c.)
2. Magazines, newspapers, and
sheet music (n. d.c .)
3. Nondurable toys and sports
supplies(n.d.c. )
4. Wheel goods, durable toys,
sport equipment, boats, and
pleasure aircraft (d. c. )
5. Radio and television
receivers, records, and
musical instruments (d.c. )
6. Radio and television
repair(s. )
7. Flowers, seeds, and potted
plants(n.d.c. )
8. Admissions to specified
spectator amusements
a. Motion picture theaters(s
b. Legitimate theaters and
opera, and entertainments
of nonprofit institutions
(except athletics ) (s. )
c. Spectator sports(s.)
9. Clubs and fraternal
organizations except in-
surance (s . )
10. Commercial participant
amusements ( s . )
11. Pari-mutuel -net receipts(s.)
12. Other(s.)
PRIVATE EDUCATION AND RESEARCH
RELIGIOUS AND WELFARE ACTIVITIES (s .
FOREIGN TRAVEL AND OTHER, NET
TOTAL PERSONAL CONSUMPTION
1965
26,298
2,061
2,868
3,436
2,933
6,013
1,032
983
1,811
. ) 927
495
389
879
1,509
734
2,039
5,927
) 5,972
3,150
432,839
1966
28,850
2,365
3.O59
3,743
3,248
6,905
1,072
1,078
1,923
964
545
414
934
1,555
765
2,203
6,608
6,421
3,196
466,334
1967
3O , 903
2,670
3,217
3,993
3,481
7,409
1,143
1,113
2,027
989
605
433
988
1,610
795
2,457
7,490
6,965
3,859
492,265
1968
33,552
2,669
3,413
4,700
4,012
7,852
1,227
1,234
2,130
1 ,045
632
453
1,049
1,675
861
2,730
8,398
7,876
7,876
536,647
EXPENDITURES
NOTE - Consumer durable commodities are designated (d.c.), nondurable
commodities (n.d.c.), and services(s.) following group titles.
78
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FINANCES OF WATER SUPPLY UTILITIES OPERATED BY LOCAL GOVERNMENTS
1966-67
Water Supply
Municipalities
Special Districts
Townships
Counties
Utility
revenue
2,187
1 , 807
258
60
62
Total
2,587
1,898
498
81
109
Utility
Current
operation
1,231
969
189
43
31
expenditure
Capital
outlay
1,055
713
243
32
67
Interest
on utility
debt
300
216
66
7
11
TABLE 29
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average daily usage per service was 202.73 gallons per day- The
average household in 1968 contained 3.23 persons. The average per
capita water consumption for domestic use is,therefore, 60.9
gallons. The cost of potable water for the average household in
January, 1970 is then computed as 10.8 cents per day, or $39.42
per year. The per capita/year cost is $12.20.
Committee Print No. 7(3) reported that the average per capita
consumption of potable water for the Nation as a whole is about
150 gallons per day per person. Of this ISO gallons about 41%
is domestic use, 18% commercial, 24% industrial and 17% public
use. Forty-one percent of 150 gallons is 61.6 which agrees well
with Seidel and Baumann.
Committee Print No. 7 also allocated the cost of producing
potable water as follows; 19% source development, 22% treatment,
and 59% distribution. Orlob and Lindorf(28) made a study of the
cost of treating potable water in 1956. The cost for a 5 mgd
plant was given as 4.3 cents/1000 gallons for debt service and
3.5 cents/1000 gallons for operation and maintenance for a total
of 7.8 cents/1000 gallons. This cost represents only 22% of the
total delivered cost. The total cost must be 52.3 cents/1000
gallons in 1967 which agrees with the Seidel and Baumann estimate.
For the production of potable water, therefore, it would appear
that the public is paying, on the average, the production cost.
Representative charges for refuse collection were gathered by
Lennox L. Moak'29/ in a study of municipalities made in January,
1961. These charges ranged from $1.00 to $2.00 per month per
household for one pickup per week. The 1967 Census of
Governmentsl2^) reported a total revenue for collection and
disposal of garbage and other wastes of 172 million dollars for
the Nation as a whole. The corresponding expenditure was given
as $888 million. Only $71 million was spent on capital outlay,
the remainder on current expenditure. If we assume that the
population served by refuse pickup is about equivalent to the
population served by water supplies (163 million) the average
expenditure for current expenditure is $5.02 per capita/yr
or about $1.35 per household per month. Current expenditure
for refuse collection is, therefore, approximately equal to the
current expenditure for municipal sewage collection and treatment.
The revenue received in user charges, on the other hand, was only
about $1.06 per capita per year or about 2O% of expenditures.
The distribution of general expenditure according to function
for municipalities is shown in Table 30.
80
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PERCENT DISTRIBUTION OF GENERAL EXPENDITURE OF MUNICIPALITIES
BY FUNCTION 1967
1. Education 16.6%
2. Highways 1O.5%
3. Public Welfare 6.6%
4. Hospitals and Health 6.8%
5. Police Protection 10.6%
6. Fire Protection 6.8%
7- Sewerage 5.8%
8. Sanitation 4.1%
Other than Sewerage
9. Parks and Recreation 4.7%
1O. Housing and Urban Renewal 4.2%
11. Terminal Facilities 2.O%
12. Libraries 1.6%
13. Financial Administration 1.7%
14. General Control 2.8%
15. General Public Buildings 1.7%
16. Interest on General Debt 3.9%
17. Other and Unallocable 9.6%
TOTAL 10O.O%
Source: 1967 Census of Governments, "Finances
of Municipalities and Township
Governments"
TABLE 3O
81
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REFERENCES
1. Federal Water Quality Administration, U. S. Department of the Interior,
1968 Inventory Municipal Waste Facilities in the United States.
2. Federal Water Quality Administration, U. S. Department of the Interior,
The Cost of Clean Water. Vol. II, Detailed Analysis, January 1968.
3. U. S., Congress, Senate, Select Committee on National Water Resources,,.
"Future Water Requirements for Municipal Use;" Senate Resolution 48,
86th Congress, 2nd session, 1959, Committee Print No. 7
4. Thoman, John R. and Jenkins, Kenneth H., Statistical Summary of Sewage
Works in the United States, Public Health Pub. No. 609, 1958.
5. Glass, A. C. and Jenkins, K. H., Statistical Summary of 1962 Inventory
Municipal Waste Facilities in the United States, PHS No. 1165, 1964.
6. Public Health Service, U. S. Department of Health, Education, and Welfare,
Statistical Summary of Municipal Water Facilities in the United States
January 1. 1963. PHS No. 1039, 1965.
7- Investment Bankers Association of America, Fundamentals of Municipal Bonds,
French-Bray Printing Co., Baltimore and Washington, 1968.
8. Bureau of Labor Statistics, U. S. Department of Labor, Mr. Dan Ginsburg,
Personal Communication.
9. Federal Water Quality Administration, Construction Grants and Engineering
Branch, Mr. R. L. Michel, Personal Communication.
10. Smith, Robert, Cost of Conventional and Advanced Treatment of Wastewater.
Jour. Water Pollution Control Fed., Vol. 40, No. 9, 1968.
11. Isard, Walter and Coughlin, R. E., Municipal Costs and Revenues Resulting
from Community Growth, Changler-Davis Publishing Company, 1957.
12. Federal Water Pollution Control Administration, U. S. Department of the
-. Interior, Problems of Combined Sewer Facilities and Overflows 1967, Water
Pollution Control Research Series, WP-20-11, 1967.
13. American Public Works Association, Collection and Treatment Cost,
Unpublished Report, 1970.
14. Bureau of Census, I960 Census of Population, Vol. I, Characteristics of
the Population. Part A. Number of Inhabitants, U. S. Government Printing
Office, Washington, D. C. 1961.
15. Thomas, H. A., Coulter, J. B., Bendixen, T. W. and Edwards, A. B.,
Technology and Economics of Household Sewage Disposal Systems,
Jour. Water Pollution Control Fed., Vol. 32, pp. 113-141, 1960.
83
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16. Downing, Paul B., "The Economics of Urban Sewage Disposal," Frederick
A. Praeger, Publishers, New York, Washington, London, 1969.
17. Federal Water Pollution Control Administration, U. S. Department of the
Interior, Sewer and Sewage Treatment Plant Construction Cost Index,
December 1967-
18. HourIon, B. J., "Sewer Maintenance is a Customer Service," Public Works,
pp. 75, February 1969.
19. Black and Veatch Engineers, Kansas City, Missouri, Mr. Don Parkhurst,
Personal Communication.
20. Smith, Robert and McMichael, Walter F., Cost and Performance Estimates
for Tertiary Wastewater Treating Processes, Robert A. Taft Water Research
Center Report No. TWRC-9, June 1969.
21. Federal Water Pollution Control Administration, U. S. Department of the
Interior, The Cost of Clean Water and Its Economic Impact, Vol. I, The
Report, January, 1969.
22. Seidel, H. R. and Baumann, E. R., "A Statistical Analysis of Water Works
Data for 1955," Jour. AWWA, 1531-66, December, 1957.
23. U. S. Bureau of the Census, Census of Manufacturers, 1963, Vol. I,
Summary and Subject Statistics, U. S. Governement Printing Office,
Washington, D. C.
24. Federal Water Quality Administration, U. S. Department of the Interior,
The Economics of Clean Water, Vol. I, Detailed Analysis, March, 1970.
25. Peters, Max S. and Timmerhaus, Klaus D., P-^ant Design and Economics for
Chemical Engineers, McGraw-Hill Book Company, Second Edition, 1968.
26. U. S. Bureau of the Census, Census of Governments, 1967, Vol. 4, No. 5,
Compendium of Government Finances, U. S. Government Printing Office,
Washington, D. C., 1969.
27. U. S. Bureau of Census, Census of Governments, 1967, Vol. 6: Topical
Studies No. 5: Historical Statistics on Governmental Finances and
Employment, U. S. Government Printing Office, Washington, D. C. 1969.
28. Orlob, G. T. and Lindorf, M. R., Cost of Water Treatment in California.
Jour. AWWA, January 1968, pp. 45-55.
29. Moak, Lennox L., Refuse Collection and Disposal Service Charges. Municipal
Finance Officers Association of U. S. and Canada, 1962.
84
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APPENDIX
The total cost of constructing wastewater treatment plants is a
function of the design capacity of the plant. If the design capacity
is expressed as millions of gallons per day, Q, the construction cost,
C, in dollars can be calculated from the following expression where C
and ji are constants.
C = CQ(Q)a (1)
If it is assumed that, on the average, each person contributes
10O gallons of wastewater per day, the per capita construction cost,
C , can be expressed in terms of the design population, D, as follows
where C and b are constants.
op -
C = C (D)b (2)
p opv ' v '
In equation (2), b_ equals (a - 1) and C equals C /(10,000)a
When a treatment plant is designed, the design capacity is made
larger than the existing population to allow for population growth.
The ratio between design population and existing population will
depend on the projected population growth for the community. If the
design period is taken as twenty years, the ratio of design population
to existing population averages about 1.5.
Using this excess capacity factor, the total cost of constructing
plants for the whole nation where the size of communities are distributed
according to the 1968 Inventory of Municipal Waste Facilities, can be
expressed as follows.
i=n
Total Cost, dollars = 1.5 CQ ^> P± (1 .SPVlSL)15 (3)
i=l
P. = number of persons in i'th population group
N. = number of plants in i'th population group
85
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To calculate the national average per capita cost this total
cost must be divided by some population. If the population existing
at the beginning of the design period is used, the per capita cost
will be a maximum. If the population selected corresponds to that
existing at the end of the design period, the per capita cost will be
minimized. On the other hand, a population corresponding to the mean
might be used. The values given in Tables XI, XII, and XVII are com-
puted using the population at the end of the design period and are
therefore, minimum values. If these per capita costs are multiplied
by the factor 1.5, they will correspond to the beginning of the
design period or approximately to current observed costs.
This problem is further complicated by the fact that the excess
capacity factor used to convert existing population to design
population has been increasing in recent years. There is no completely
satisfactory way of computing the national average per capita construction
cost.
86
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1
V
5
Acceauion Number
V
2
Subject Field & Group
06C
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
Organization
Advanced Waste Treatment Laboratory, Cincinnati, Ohio
Titla
Cost to the Consumer for Collection and Treatment of Waste-water
10
Authors)
Robert
Smith
16
Project Designation
17090 07/70
Richard G. Eilers
Note
22
Citation
23
Descriptors (Starred First)
*Sewage Treatment, *Sewers, *Tertiary Treatment, *Construction Costs, *Annual Costs,
Cost Comparisons, Allocation (Cost), Income Analysis, Comparative Costs, Maintenance
Costs, Operating Costs, Unit Costs, Water Costs, Cost Trends, Economies of Scale,
Efficiencies, Interest Rate, Prices, Salaries, Water Rates
95 Identifiers (Starred First)
27
Abstract
The national average per capita cost for collection and treatment of
municipal wastewater is computed based on the 1968 Inventory of Municipal Waste
Treatment Facilities in the United States and per capita cost relationships for
building and operating collection and treatment facilities. All costs are given
per capita served with treatment facilities using the level of treatment existing
in 1968. Total cost was computed as $19.8O per capita per year. Of this total,
$15.31 represents amortization charges and $4.49 represents current charges.
The total cost can also be broken down as $13.34 for collection, $4.38 for treat-
ment and $2.O8 for overhead such as customer services, administrative, and general.
The cost of collection is, therefore, about three times as expensive as treatment.
Nationally, about 23% of the total cost is paid as sewerage usage charges.
This represents about 0.1% of National Personal Consumption Expenditures. Expendi-
ture for water supply averaged $13.42 per capita per year and this is about equal
to the amount paid by the consumer in user charges for water supply.
The current status of collection and treatment in the United States is
discussed and estimates are made of needed additional expenditure.
Abstractor
Richard G. Eilers
Advanced Waste Treatment Research Lab., Cincinnati, OH
WR:\02 (REV. JULY
WRSI c
SEND, WITH COPY OF DOCUMENT. TO: WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON, D.C. 20240
«U.8. GOVERNMENT PRINTING OFFICE: 1972 484-484/129 1-3
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