United States Revised
Environmental Protection September
Agency 1983
&EPA Less Costly
Wastewater
Treatment
for Your town
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The Right Stuff: Choosing the
If your town needs to build, upgrade or re-
place its sewerage system, you'll want to
choose the right system This means one
that will do the job but won't bankrupt the
community The key to getting the best sys-
tem at the lowest cost is choosing the right
technology - the APPROPRIATE technology
for your town
Appropriate
Technology
Appropriate technology means a simple sys-
tem that your community has the means to
build, operate, and maintain and that provides
proper treatment for your wastewater
As Federal grants for wastewater facilities
phase down and State and local budgets be-
come tighter, appropriate technology takes
on even more importance
Conventional
Technology
Conventional technologies are the popular
methods used to collect and treat
wastewater Normally, they are not the best
alternative for a small community
Conventional Treatment
Conventional treatment plants are com-
plicated mechanical systems They were de-
veloped for larger cities to save space, but
they use large amounts of energy These
systems are generally costly for small com-
munities and need skilled operators Con-
ventional treatment most often uses a pro-
cess called activated sludge
Conventional Sewers
Conventional gravity sewers are the
wastewater collection method usually pre-
ferred, but the cost per household increases
greatly in rural areas and where the ground is
hilly, rocky or wet
Appropriate
Technology
for Small
Communities
Appropnate technologies are generally more
suitable for small communities because they
are simpler to operate and less costly
Treatment Systems
Simple and reliable treatment systems that
generally cost less to build and operate in-
clude
• Lagoons
• Land treatment
• Trickling filters
• Oxidation ditches
They generally use less energy than con-
ventional treatment
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Appropriate System
Alternative Sewers
Alternatives to conventional gravity sewers
include
• Pressure sewers
• Small-diameter gravity sewers
They are installed at shallow depths and do
not need the wide trenches or costly man-
holes of conventional sewers Many small
communities can best be berved by a com-
bination of sewer technologies, e g con-
ventional gravity sewers in densely de-
veloped areas and alternative sewers in outly-
ing areas
Onsite Systems
One of the most swtable technologies for
small unsewered communities or parts of
communities is onsite systems Onsite sys-
tems such as mounds, sand filters.
alternating beds and low pressure distribution
can replace or upgrade failing septic systems
Where lot sizes or soil conditions aren’t
suitable for onsite syste ms, cluster systems
can be used Here, wastewater is conveyed
by small-diameter sewers to a neighborhood
drainfield, mound, or sand filter
Construction and operating costs for onsite
or cluster systems are usually low and the
systems can be very simple to operate The
key to their success is an efficient organiza-
tion to manage their operation and mainte-
nance
Technology The graphs shown here compare costs of
Costs apnropria le technologies to costs of con-
for Small ventional technology A range of costs is
Communities shown for the vanous appropriate tech-
nologies
The information presented in the graphs
assumes
• Costs are in September 1982 dollars
• An average household produces 200 gal-
lons of wastewater a day
• No wastewater flow from industries
• 75% Federal funding (85% for alternative
technologies such as land treatment, alterna-
tive sewers and onsite systems) and no
State funding
• All construction costs qualify for EPA
grant funding (For most projects, some costs
usually don’t qualify)
• A 20-year loan at 12% interest to pay the
local share of construction cost
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• Centralized treatment costs are for a com-
plete. custom-built system, induding sludge
handling.
• Collection system costs indude the cost
of house se ,vers.
• Costs for onsite systems are for 25%-
50% replacement of existing onsite systems.
The cost of an onsite system management
program is also induded.
• land would cost $1,500 per acre.
Treatment Consbu on Coats
Costs Const,uction costs for a wastewater treat-
ment facility cover the cost to build it and re-
lated costs such as engineering and legal fees.
Agure I compares the construction costs
of conventional and appropriate treatment
systems. These are the costs a community
would pay to build a treatment facility with
no grant funding. The range of costs for
appropriate technologies is indicated by the
shaded band.
For a community of 3,500, conventional
activated sludge has an average cost of $1.2
million. Compare this with appropriate tech-
nology costs. They range from $500,000 to
Si mlllio.
Houeah d Coat
A community’s cost to treat wastewater con-
sists of two parts. One is its share of the
cost to build the facility. The other is the cost
to operate and maintain it and replace equip-
ment as it wears out. Household cost is the
annual amount a typical customer pays to
cover these costs.
Figure 2 shov is househoki costs for acti-
R r e1 Agure2
ConàuctlonCàsts for Treatment Annual Houeahokf Cc
1OOO(O.O7mg
Population (not
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vated sludge treatment and a range of appro-
priate treatment technologies for three com-
munity sizes. There are two appropnate tech-
nology bars for each community size. They
indicate the high and k)w cost in the range of
costs for the various appropriate systems.
For communities of 3.500 people, activated
sludge treatment averages about Si 20 per
household per year. while appropriate tech-
nologies range from $50 to $90. Tridduig fil-
ters and oxidation ditches tend to be in the
higher part of the range while lagoons and
land treatment tend toward the lower cost
range. Note that:
• Wth 75% Federal funding, operation and
maintenance makes most of the house-
hold cost;
• Most facilities are built with some reserve
capacity for future users. Initial users will like-
ly pay higher charges than those shown until
future users come on line.
For a small community, the cost of con-
ventional sewers accounts for 8O% 90% of
the total cost to build a wastewater collection
and treatment system. Alternative sewers
can greatly reduce collection system costs.
Figure 3 shows total annual household
costs of collection systems for communities
with less than 10.000 people.
The costs shi vn in the graph are for ideal
conditions: flat ground, good soil, and no
groundwater problems. In hilly areas, the con-
struction cost advantage of pressure sewers
increases. Alternative sewers, especially
pressure sewers, have a cost advantage in
wet soil conditions. In small communities,
alternative sewers qualify for 85% funding.
Rgiare 3
old Costs for Treatmant
Dcons
• peisticm ard Maintenance
A Activated S ludge
8 fr propnate Technologies
Costs asst me 75% funding
(85% fo A ernat ve fe L
n
Annum Household Costs for Sewere
- -. óT5 06
Ntemabve
I 6000 R000
Cos
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Although not included in this cost informa-
tion, vacuum sewers have shown promise in
certain situations.
Total Unsewered communities may need a m-
System plete waslewater system. This can mean
Costs sewers and a treatment facility or upgraded
onsite systems with a management program.
The most suitable approach may be a central
system for part of your community and
onsite or duster systems for the remainder.
Figure 4 compares the total annual costs of
a conventional system (activated sludge with
gravity sewers) to costs for appropriate cen-
tralized and onsite technologies for three
community sizes.
Appropriate systems cost less than con-
ventional systems in all three communities.
Onsite systems cost the least. They need kt-
tie or no sewenng and qualify for 85% Feder-
al funding.
Households in a community of 3.500
would pay about:
• $60-SI 30 a year for onsite systems;
• $1205200 a year for appropriate treat-
ment and collection;
• $300 a year for a conventional system
under best conditions for gravity sewers.
Hilly, rocky, or wet conditiors would widen
the cost difference between appropriate and
conventional central systems. Onsite system
costs may increase under the same conditions.
Effects of After Sept 30,1984. the EPA funding share
Venous Levels of of a project’s cost will decrease from 75% to
Federal Funding 56%. The EPA share for innovative or alterna-
tive technology goes from 85% to 75%. The
R4 Rgure5
Annual Household Cost Comparison for Annual HauSbhOId Costs at Varic
Total System
community
Popi Ioe
Federal
Share
%
Trs.tm
Conven+Jond A
.
1,000
75
55
0
270
320
470
3,500
75
55
0
120
150
220
-
10,000
.
75
55
0
70
9O
130
:) 1(
Note: Alternative Technology Federal
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EPA share may be reduced further after
Sept. 30, 1985. when Congressional au-
thorization for EPA’s grant program expires
Figure 5 shows how vanous Federal
funding levels (75%, 55%, 0%) would affect
household costs for communities of 1.000.
3.500. and 10,000
For a town of 3.500. reduction of the EPA
share from 75% to 55% means a 50% in-
crease in the household costs for a con-
ventional system It means a 33% to 53% in-
crease for appropriate technology Household
costs nearly tnple for a total system with
either technology when there is no Federal
funding At 55% funding, onsite system
household costs increase about 50% With-
out Federal funds they would double or triple
Other Cost isn’t the only factor to consider in
Factors choosing a wastewater system
• Conventional treatment plants are more
difficult to operate than appropriate systems
They’re generally more sensitive to flow var-
iations They use more energy but are less
sensitive to cold climates than most appropn-
ate technologies
• Lagoons and land treatment have low
sludge disposal needs but they need more
land than the other technologies
• There is less seepage of clear water into
alternative sewers, so flow at the treatment
plant is less
• Small-diameter gravity sewers and some
pressure sewers transport wastewater from
septic tanks This means the wastewater has
had some treatment when it reaches the
treatment facility
bus Levels of Federal Funding ($ per year)
n . m
Collection
Total System
Appropriate
Conventional
Appropriate
bonventionai
Centralized
Appropriate
Onsite
120-230
130-270
200-400
230
390
840
100-150
150-200
510-540
500
710
1310
220-380
280-470
710-940
60-130
90-240
140-440
50-90
50-110
90-170
180
300
660
70-110
110-150
400-420
300
450
880
120-200
160-260
490-590
60-130
90-240
140-440
30-50
30-60
60-90
140
250
530
60-100
90-130
320-3 50
210
340
660
90-150
120-190
380-440
60-130
90-240
140-440
Shares 85%, 75%. 0%
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The Appropnate technology can benefit your town
Right Stuff in many ways
Saves Money • Lower cost to build, operate, maintain,
• Lower user costs,
• Less energy use,
• Less sludge,
• Simpler to operate
More Get more facts on appropriate technology
Infnrmatiflfl! from
• EPA Small Wastewater Flows Clearing-
house
West Virginia University
Morgantown, WV 26506
800-624-8301 or 293-4191 (in West Virginia)
• EPA Foldout on 21 Small Wastewater
Systems (FRD-1O),
• EPA Onsite Wastewater Treatment and
Disposal Systems Design Manual,
• EPA Innovative and Alternative Technolo-
gy Assessment Manual (MCD-53)
• Your EPA Regional Office
I Boston (Conn, Maine, Mass. N H. R I. Vt)
JFK Federal Building, Boston. MA 02203
617-223-7210
2 NewYork (NJ.NY.PR.VI)
26 Federal Plaza, New York, NY 10007
212-264-2525
3 Ph iladelphia (Del, Md, Pa. Va, WVa, DC)
6th & Walnut Sts, Philadelphia, PA 19108
215-597-9814
4 Atlanta (Ala, Ga, Fla, Miss. N C, S C , Tenn, Ky)
345 Courtland St. N E. Atlanta, GA 30308
404-881-4727
5 Chicago (Ill. Ind, Ohio, Mich, Minn, Wis,)
230 S Dearborn St. Chicago, IL 60604
312-353-2000
6 Dallas (Ark, La,Okla,Tex, NMex)
1201 Elm St. Dallas, TX 75270
214-767-2600
7 Kansas (iowa, Kans, Mo, Neb)
324 E 11th St . Kansas City, MO 64108
816-374-5493
8 Denver (Cola, Utah, Wyo, Mont. N D, S 0)
1860 Lincoln 5 *, Denver, CO 80203
303-837-3895
S San Francisco (Anz, Calif . Guam. Hawaii. Nev, Amer Samoa,
Twst Terntories of the Pacific)
215 Fremont St. San Francisco, CA 94105
415-974-8088
10 Seattle (Alaska, Idaho, Oreg, Wash)
1200 6th Aye, Seattle, WA 98101
206-442-5810
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