TD433
.512
United States
Environmental Protection
Agency
Office of Water
Program Operations (WH-595)
Washington DC 20460
October 1979
FRD-9
Determining
Wastewater Treatment
Costs
for Your Community
430979507
U.S. Environmental Protect Agency
Region V, Library
23d Soutfc Dearborn Street
Cfrfcggo. Illinois 60604
SORg^Y
%
M.F.X,Mi»HI* HKMTII WIT
-------
Copies of this Publication, FRD-9, Determining
Wastewater Treatment Costs for Your Community
are available from the address below. When
ordering, please include the title and FRD
number.
General Services Administration (8FSS)
Centralized Mailing Lists Services
Building Ul, Denver Federal Center
Denver, Colorado 80225
-------
Determining Wastewater
Treatment Costs for
Your Community
This publication was prepared for the U.S.
Environmental Protection Agency by Sage Murphy
and Associates, Inc., Denver, Colorado under the
direction of:
James A. Chamblee, Chief
Priorities & Needs Assessment Branch (WH-595)
Office of Water Program Operations
U.S. Environmental Protection Agency
Washington, D.C. 20460
(202) 426-4443
-------
Table of Contents
Page No.
Why Treat Wastewater 2
How Wastes are Collected 3
Costs for Wastewater Collection 4
Enlargements and Upgrades of Existing
Wastewater Treatment Plants 7
Costs for Wastewater Treatment 7
New Plant Construction Costs 9
Operation, Maintenance, and Routine
Replacement Costs 12
Component Parts of Annual Operating
and Maintenance Costs 14
Annual Treatment Plant Operating
Expenses 16
11
-------
INTRODUCTION
Public Law 95-217, The Clean Water Act of
1977, has mandated the nation's waters must be
protected from pollution and existing pollution
levels must be reduced. One of the provisions
of the Act is to assist municipalities and other
public dischargers of waste with the financial
burden of necessary construction of the
pollution control facilities. In most cases,
the Federal government will contribute 75
percent of the construction costs while the
local share will be 25 percent.
In addition, EPA encourages small treatment
systems and innovative and alternative treatment
systems; because they often are less costly than
traditional treatment methods, resulting in cost
savings to both the community and EPA.
Innovative and alternative treatment systems can
receive up to 85 percent Federal funding.
In order to choose the most viable approach
for wastewater treatment, it is important that
communities have a general idea of the potential
costs as they begin the planning process. The
U.S. Environmental Protection Agency (EPA) is
providing this brochure to assist you and your
community in determining the approximate cost of
building and operating a municipal wastewater
collection and treatment system. The brochure
has been developed for facilities serving less
than 50,000 people.
We have developed the cost to your
community, which is "average" for the population
served. The data from which these estimates
were derived are from national averages. Costs
in your locality will probably vary from these
averages due to regional economic differences,
-------
climate, terrain, and other factors. Before
outlining this general cost information, it is
necessary to present background information on
wastewater collection and treatment, as well as
some of the assumptions used to arrive at these
national averages.
WHY TREAT WASTEWATER
Water has long been used to transport
unwanted materials away from our homes,
businesses, and industries. About 26 billion
gallons of wastewater are generated in the U.S.
daily. The wastewater is composed of organic
compounds from plants, animals, and humans; and
inorganic compounds from household activities,
industrial proceses, and commercial practices.
These wastes take the form of particles
suspended in the water, commonly called
Suspended Solids (SS) or wastes that are
dissolved in the water. Suspended solids can
harbor harmful microorganisms (typhus, polio,
etc.) and toxic chemicals.
Organic matter in wastewater serves as food
for bacteria and other small organisms. The
amount of oxygen needed by the organisms to
oxidize the organics for food and energy is
called Biochemical Oxygen Demand (BOD). BOD is
an important measurement, as aquatic life is
dependent upon the amount of oxygen in the
water. A depletion of available oxygen can
decrease the desirable aquatic populations in
our waterways, causing fish kills for example.
Inorganic materials present problems also.
Phosphorus and nitrogen act as nutrients for
algae and other growths which can deplete
streams of oxygen, can cause odor problems, and
-------
are generally unsightly. High levels of certain
chemicals such as mercury, lead, cadmium, and
zinc are suspected of causing certain sicknesses
in humans.
Untreated wastewater can, therefore, deplete
our streams of fish and wildlife, transmit
diseases, reduce property values, and generally
prove a public nuisance and health hazard.
HOW WASTES ARE COLLECTED
Our sewer systems are composed of piping,
pump stations, manholes, and associated items.
The sewer pipes are separated into four
categories: house connections, collectors,
interceptors, and force mains. These different
types of sewers may be compared to our city
street system: house connections are similar to
driveways, collectors are similar to suburban
streets, interceptors are similar to major
highways.
House connections carry wastewater from the
house into the collection system. The cost of
house connections must be borne completely by
the homeowner. The wastewater flows from house
connections into collector sewers. Collector
sewers are eligible for Federal funding in
communities existing before October 1972, where
there are no sewers now. New communities, or
newly developed areas of existing communities
must bear the entire cost of the collectors. In
many States, however, collector sewers do not
receive a sufficiently high priority to receive
any funds. The main conveyance pipe which
gathers flows from the collectors and transports
the wastewater to the treatment plant is called
an interceptor. Depending on the terrain, a
force main may be necessary to carry water,
-------
under pressure, from a pump station to the
treatment plant. Interceptors, force mains, and
pump stations are all fundable by the Federal
government. The Federal government will pay 75
percent of the cost on all eligible items. The
community is responsible for finding funds to
cover the remaining costs.
COSTS FOR WASTEWATER COLLECTION
The costs of a sewer system vary widely
among different localities. These variances are
influenced by climate, terrain, population
density, soil condition, and cost of living to
name but a few. Reasonable costs for the grant
eligible portion of a sewer system range from
$500 to $1,500 per person served, the average
being approximately $1,000 per person. This
average is for those communities with eligible
collector and interceptor sewers. Of these
totals, the Federal government pays $750 per
person and the community pays $250 per person,
on the average. The homeowner must pay any
additional costs for the house connection and
any hookup charges.
If your community is not eligible for
Federal grants for the collector systems, and
none are presently existent, the total costs
will remain approximately the same, but the
community will be responsible for a greater
share. The cost of the collection system must
be added to the treatment costs mentioned later
in the brochure to give an estimate of total
costs.
HOW WASTES ARE TREATED
Wastewater treatment is designed to
-------
accomplish in a controlled and managed
environment what occurs in nature under a much
slower process. The contaminants are removed
from the wastewater by various physical,
chemical, and biological processes.
There are three basic levels of wastewater
treatment: primary, secondary, and advanced
treatment. The objective of primary treatment
is to remove readily settleable and flotable
material, thus reducing the amount of suspended
solids (SS). Secondary treatment is designed to
remove dissolved pollutants and provide greater
efficiencies in suspended solids removal.
Advanced treatment is used for phosphorous and
nitrogen removal or for greater reduction of BOD
and SS.
The effluent (treated wastewater) of a
sewage treatment plant must meet certain Federal
or State water quality criteria. Secondary
treatment is now the minimum requirement.
Advanced treatment may be required if the
receiving body of water is particularly
sensitive to certain pollutants, or to protect
the health and welfare of people and wildlife.
Since secondary treatment is the minimum
level of treatment required by law and is
usually used in conjunction with primary
treatment, emphasis will be placed on it. Most
new treatment plants in this country will be
some form of secondary. Secondary treatment
utilizes the natural process of microorganisms
feeding on organics in the water which reduces
the BOD. The process creates an ideal, confined
habitat, providing proper light, temperature,
oxygen, and food for the microorganisms. A
secondary treatment plant generally consists of
screening devices, a settling tank (primary
-------
treatment, SS removal), a biological treatment
unit (secondary process, BOD removal), a
secondary settling tank, and chlorination
(disinfection). The material settled out in
sedimentation tanks, called sludge, is further
reduced or densified by digestion, thickening,
drying, or incineration processes for safe and
easy final disposal.
A variety of biological processes can be
used for secondary treatment. Some of the most
common are lagoons, activated sludge, and
trickling filters. Lagoons are large shallow
ponds where wastewater is held for a period of
time while a biological community feeds on the
organics in the wastewater. Some lagoon designs
provide for addition of oxygen to the ponds by
using aerators, thus increasing the biological
activity and treatment efficiency. Activated
sludge processes consist of a tank in which
sufficient air is supplied to support a
biological community. With trickling filters,
the biological communities are grown on a fixed
media rather than in the water. Trickling
filter plants spray the wastewater onto rocks or
plastic media to which microorganisms attach
themselves and use the wastewater as a food
source.
Plant size, strength of incoming wastes,
effluent requirements, climate, energy
requirements, and operating manpower
requirements are some of the factors which bear
upon the selection of secondary treatment
processes.
Advanced treatment can usually be achieved
by adding processes to a secondary plant. Some
advanced treatment processes add chemicals which
enhance the settling properties of the suspended
-------
materials. Some are processes which use a form
of filtration to refine the secondary effluent.
Land treatment of wastewater may achieve
advanced treatment standards by applying
partially treated wastewater to land.
ENLARGEMENTS AND UPGRADES OF EXISTING WASTEWATER
TREATMENT PLANTS
Existing treatment plants that cannot meet
present effluent requirements must be upgraded.
This includes all primary plants, since
secondary treatment in now the required minimum
level of treatment, and plants in areas where
discharges are restricted and advanced treatment
is required. An upgrade can range from the
modification of present processes to the
addition of totally new processes. A treatment
plant may also need to be enlarged to relieve
overloaded conditions. The type and extent of
the needed additional construction is dependent
upon the individual community and the existing
plant (present capabilities, adaptability to
modification, etc.). In enlarging and
upgrading, a complete evaluation of the existing
system is essential along with a detailed study
of alternatives. Costs associated with
enlarging and upgrading plants are so plant
specific that reasonable cost estimates cannot
be presented within the scope of this brochure.
COSTS FOR WASTEWATER TREATMENT
The choice of treatment alternatives is
dependent upon variables such as climate, land
availability, waste constituents, effluent
restrictions, general community goals, process
reliability, and costs. There is no single best
-------
8
method of treatment. The deciding factor when
considering alternatives often is system costs,
not only the initial capital outlay, but also
the yearly charges that the community must meet.
The Federal government will fund 75 percent
(85 percent in some cases) of the costs for
treatment plant construction. This includes new
construction, enlarging or upgrading a plant.
The only nonfundable portion is the cost of the
land on which the plant is built. Land is
fundable only if it is used for land application
of wastewater. The annual operation and
maintenance costs of the treatment facility are
completely the responsibility of the community.
These costs are shared by the homeowners through
hookup and user charges. Industries which
discharge into the treatment system pay a
portion of yearly operating expenses in
proportion to their use.
Costs are presented for lagoons, other
secondary plants, and advanced treatment
plants. Costs presented include total cost for
new construction, yearly treatment plant
operation, maintenance, and routine replacement
cost, and the annual operating expenses of the
plant. These costs may vary due to regional
labor rates, chemical costs, utility costs, and
construction material costs. All costs are in
January, 1979 dollars. Estimates for inflation
between that time and now should be used to
determine the present cost.
-------
NEW PLANT CONSTRUCTION COSTS
Figure 1 provides average costs (in millions
of dollars) derived from historical data for
construction of new plants. A general
assumption made when determining plant size is
that 100 gallons of wastewater per person per
day is generated. The graph covers a population
of zero to 50,000. The actual flow for a
community can vary widely depending upon locale,
climate, size of community, and the degree of
industrialization.
EXAMPLE
The example presented below provides new
plant construction costs; annual operation,
maintenance, and routine replacement costs; and
annual treatment plant operating expenses for
constructing and operating a new secondary
treatment plant for a community of 25,000 people.
POPULATION:
NEW PLANT CONSTRUCTION COSTS: From the graph in
Figure 1, follow the line up from the population
(25,000) until it cuts across the secondary
treatment curve. Follow the line across the
vertical cost scale. Read the cost from the
scale in millions of dollars = 4.8 million
dollars.
CAPITAL OUTLAY = 4.8 x 1,000,000 = $4,800,000
-------
10
SAMPLE FORM (For your community)
POPULATION SERVED:
TREATMENT
LEVEL:
CAPITAL OUTLAY: From the graph in Figure 1,
trace a line up from the
population to the treatment level
curve, across the cost scale. Enter the cost in
the blank and multiply by 1,000
dollars. x 1,000 dollars
= . Enter this figure in the blank
below for new plant construction costs.
CAPITAL OUTLAY = $
-------
FIG. 1
NEW PLANT CONSTRUCTION COST
9-
8-
7-
§ '-«
S 5-
_i
I
v_ 4-
t-
o
U 3-
2-
1-
^
AWT
.^*
SECONDARY
„
+ .»»»°
0^°°l LAGOONS
,-"""
5 1O 15 2O 25 3O 35 4O
POPULATION (THOUSANDS OF PEOPLE )
0
ASSUMING 1OO GAL. PER CAPITA PER DAY
-------
12
OPERATION, MAINTENANCE, AND ROUTINE REPLACEMENT
COSTS
Figure 2 presents annual costs (in thousand
dollars per year) to operate and maintain
treatment plants. Costs for lagoons, secondary,
and advanced treatment plants are given.
EXAMPLE
ANNUAL OPERATION, MAINTENANCE, AND ROUTINE
REPLACEMENT COSTS: From the graph in Figure 2,
follow the line up from the population (25,000)
until it cuts across the secondary treatment
curve. Follow the line across to the vertical
cost scale. Read the cost from the scale in
thousands of dollars per year = 200 thousand
dollars
O&M COSTS: 200 x 1,000 = $200,000 per
year
SAMPLE FORM (For your community)
ANNUAL OPERATION, MAINTENANCE, AND ROUTINE
REPLACEMENT COSTS: From the graph in Figure 2,
trace a line up from the population to
the treatment level curve, across to the cost
scale. Enter the cost in the blank and multiply
by 1,000 dollars. x 1,000 dollars
= . Enter this figure in the blank
below for total annual operation, maintenance,
and routine replacement cost, in dollars per
year.
O&M COST = $ PER YEAR
-------
FIG. 2
ANNUAL O & M COSTS
6OO-1
soo-
tt
<
_i
O
o
O
z
<
«/)
O
I/)
O
400-
300-
2OO
100-
X
AWT
SECONDARY
LAGOONS
O 5 1O 15 2'O 25 3O 3'5 4'O 45 5O
POPULATION (THOUSANDS OF PEOPLE)
ASSUMING 1OO GAL.PER CAPITA PER DAY
-------
14
COMPONENT PARTS OF ANNUAL OPERATING AND
MAINTENANCE COSTS
The pie diagram (Figure 3) below
demonstrates the relative proportions of
components which make up the annual cost of
operating and maintaining a plant. This can aid
a community in determining what impacts future
increases in utility rates, chemical costs,
labor rates, or routine replacement costs will
have on operating costs.
-------
:IG.3
PROPORTIONATE O & M COSTS
.AGOONS
SECONDARY
AWT
UTILITIES
MATERIALS
CHEMICALS
OTHERS (4%)*
UTILITIES
MATERIALS
CHEMICALS
OTHERS
UTILITIES
MATERIALS
CHEMICALS
OTHERS
-------
16
ANNUAL TREATMENT PLANT OPERATING EXPENSES
Annual operating expenses are those costs,
calculated on a yearly basis, required to own
and operate a facility. They include principal
and interest payments for retirement of any debt
acquired for the construction, yearly salaries
for manpower (including overhead and fringe
benefits), chemical and power costs for
operation, and all costs associated with routine
replacement and maintenance of the facilities.
Annual operating expenses for municipalities
were developed assuming 75 percent Federal
funding and 25 percent municipal funding of
construction costs, general obligation bonding
at six percent compounded semiannually for 20
years, and 100 percent municipal funding for
annual operation and maintenance costs. The
municipality's share in terms of annual
operating expenses (in thousands of dollars per
year) is presented in Figure 4 for a population
range of zero to 50,000.
-------
17
EXAMPLE
ANNUAL TREATMENT PLANT OPERATING EXPENSES: From
the graph in Figure 4, follow the line up from
the population (25,000) until it outs across the
secondary treatment curve. Follow the line
across from the intersection to the vertical
cost scale. Read the cost from the scale in
thousands of dollars per year = 325 thousand
dollars.
ANNUAL TREATMENT PLANT OPERATING EXPENSES =
325 x 1,000 = $325,000 per year
SAMPLE FORM (For your community)
ANNUAL TREATMENT PLANT OPERATING EXPENSES: From
the graph in Figure 4, trace a line up from the
population to the treatment level
curve, across to the cost scale. Enter the cost
in the blank and multiply by 1,000
dollars. x 1,000 dollars
= . Enter this figure in the
blank below for the annual treatment plant
operating cost in dollars per year which
includes the municipality's 25 percent share of
the capital outlay and the bond debt retirement
plus the annual operation, maintenance, and
routine replacement costs.
ANNUAL TREATMENT PLANT OPERATING EXPENSES =
$ per year.
The annual treatment plant operating
expenses are a rough planning level estimate of
what the new treatment plant will cost the
community.
Remember that the actual costs in your
community may be very different; because we have
used national average costs for treatment
plants, and we have not included any costs for
the sewage collection system.
-------
FIG. 4
8OO-
< 7OO-
BL 600-
(A
Of
j 5OO-
O
O
O 4OO-
z
O 300
O
u
200-
100-
ANNUAL TREATMENT PLANT
OPERATING EXPENSES
AWT
*
%
SECONDARY
....... ,
"
................
LAGOONS
1O 15 2O 25 3O 35 4O 45 SO
POPULATION (THOUSANDS OF PEOPLE)
ASSUMING 1OO GAL. PER CAPITA PER DAY
-------
19
REFERENCES AND ADDITIONAL SOURCES OF INFORMATION
1. Environmental Pollution Control
Alternatives: Municipal Wastewater
(EPA-625/5-76-012).
2. A Primer on Wastewater Treatment (Office of
Public Affairs, A-107, July 1976).
3. Construction Costs for Municipal Wastewater
Treatment Plants: 1973-1977
(EPA-430/9-77-013, MCD-37).
M. Analysis of Operation and Maintenance Costs
for Municipal Wastewater Treatment Systems
(EPA-430/9-77-015, MCD-39).
5. Construction Costs for Municipal Wastewater
Conveyance Systems: 1973-1977
(EPA-430/9-77-014, MCD-38).
6. Cost Effective Comparison of Land
Application and Advanced Waste Treatment
(EPA-430/9-75-015, MCD-17).
7. All You Need to Know About Sewage Treatment
Construction Grants (Office of Public
Affairs, A-107, August 1976).
•V U S GOVERNMENT PRINTING OFFICE 1979 — 681-529
-------
------- |