&EPA
United Stales
Environmental Protection
Agency
Office of Water
Program Operations (WH-547)
Washington DC 20460
September 1983
Affluent Effluent
New Choices
in Wastewater Treatment
^•^^, _^T/\[
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AFFLUENT EFFLUENT: NEW CHOICES IN WASTEUATER TREATMENT
This publication is a collection of case histories illustrating
the successful use of innovative and alternative
wastewater treatment systems.
It is a Companion Guide
to the film Affluent Effluent.
It was prepared for the Office of Water Program Operations,
U. S. Environmental Protection Agency,
by
Urban Scientific and Environmental Research, Inc.
1509 Phoenix Road
Phoenix, MD 21131.
1983
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TABLE OF CONTENTS
ONSITE AND SMALL SYSTEMS
Onsite Wastewater Management Program 1
o Stlnson Beach, CA developed an effective program to
oversee and manage the use of onsite treatment systems.
Diagnosing Falling Septic System 5
o Mashpee, MA used new technologies to Identify failing
on-site systems.
Cluster System
o Rothsay Camp, Ottertail County, MN built a community
leachfield when individual leachfields were Inadequate.
Mound System 9
o Prono, MN combined an on-site management program with
an innovative mound system to compensate for poor-
draining local soils.
Pressure Sewers 12
o Manila, CA chose a low pressure sewer system as a low
budget alternative to solve health and environmental
hazards created by failing septic tanks.
CONVENTIONAL TREATMENT WITH ALTERNATIVE OR INNOVATIVE ADD-ONS
Good Operation and Maintenance 15
o Portland. OR optimizes the performance of Its conventional
treatment plant by controlling influent characteristics
and investing in operation and maintenance.
Urban Irrigation 17
o St. Petersburg, FL solved water-shortage and pollution
problems by using treated wastewater for landscape
irrigation.
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Spray Irrigation of Crops 19
o Paynesville. MN helps local fanners meet Irrigation
problems by using treated wastewater for feed crop
irrigation.
Land Reclamation/Wildlife Enhancement 22
o Martinez, CA created a marsh which provides advanced
wastewater treatment, and offers a home to a wide variety
of wildlife.
Sludge Composting 25
o Durham, NH turns the sludge from a secondary treatment
plant into compost for landscaping and gardens.
Methane Conversion for Fuel 28
o Modesto, CA is using methane from digester tanks to run
a fleet of cars and trucks.
NON-CONVENTIONAL SYSTEMS
Overland Flow Land Application 31
o Easley, SC is experimenting with an overland flow method
that relies on soils and plants to treat raw sewage and
lagoon effluent.
Solar Aquaculture 34
o Hercules, CA adapted NASA's research to treat wastewater
by using aquatic plants in a greenhouse environment. These
"aquacells even remove heavy metals from the water.
Plans for Complete Recycling 37
o San Diego, CA hopes to solve its water-shortage problems
by using aquaculture on a grand scale to completely recycle
all water.
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NON-STRUCTURAL APPROACHES FOR WASTEWATER MANAGEMENT
Comprehensive Planning For Entire Water System 41
o Monterey, CA established a regional planning commission
to coordinate all programs and investments effecting the
water cycle.
Watershed Ordinance 44
o Crested Butte, CO protects its water supply with a
watershed ordinance.
Water Conservation Strategies 46
o Many communities concerned with inadequate water supply
or inadequate wastewater treatment capacity have proven
that water conservation is an effective low-cost solution
to these problems.
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INTRODUCTION
This companion guide to the film
Affluent Effluent provides detailed
information on each of the case studies
presented in the film. Contacts for
further information are cited following
each case history. Several additional
cases are included in this publication
that did not appear in the film. These
additional examples present an even
broader spectrum of technologies and
management techniques.
The information in this document has
been funded wholly or in part by the
United States Environmental Protection
Agency under Grant No. T900892010 to
Urban Scientific and Educational
Research, Inc. It has been subject to
the Agency's peer and administrative
review, and it has been approved for
publication as an EPA document. Mention
of trade names or commercial products
does not constitute endorsement or
recommendation for use.
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THE FILM
Affluent Effluent is a 40 minute color film available in 16mm and 3/4"
video cassette for televised broadcast.
The film was produced for use by community decision makers. Affluent
Effluent introduces new choices for wastewater treatment including small
systems for individual homes (onsite systems); Innovative additions to
conventional wastewater treatment systems; non-conventional systems; and
non-structural alternatives to wastewater management including water
conservation measures that result in reduced wastewater flows. Use of this
film will increase understanding of non-conventional wastewater treatment
technologies and promote sound investment decisions.
Selecting a wastewater management system is one of the most important
and costly investment decisions that a community makes. The success of this
investment decision can affect the community's ability to grow, its credit
rating, the taxes its citizens must pay, the effectiveness of wastewater
treatment, and the quality of its water resources.
WHAT ARE THE ISSUES?
The people who work, live with, and pay for these non-conventional
wastewater treatment systems discuss the questions you would like to hear
answered:
o How does it work?
o How much does it cost?
o How and why they chose the system?
o What about public acceptance?
o What costs and what benefits?
o What was the political process that allowed this
option?
Affluent Effluent demonstrates that a community can develop sound
wastewater treatment systems by applying local ingenuity, good engineering,
and a determination to solve their problems at lower costs to the taxpayer.
HOW CAN THE FILM BE USED?
If you are a community decision maker;
This film can save your community money and make your job easier.
Obtaining the first hand information you get from viewing this 40 minute film
would be costly if obtained from private research and travel. You could spend
hours of your own time reading technical documents and traveling to gain
similar information. One good Idea from this film could save your community
thousands of construction, maintenance and operation dollars.
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You will want to show this film to a citizen advisory group, finance
committee, consulting engineers, overseeing government agencies, and
taxpayers.
If you are a consulting engineer:
Affluent Effluent can be used to educate local decision makers on a
range of creative solutions to wastewater treatment problems. It can be
used for:
o general information and education
o workshops on wastewater treatment
o promoting constructive discussion among conflicting
groups
o generating public interest
If you are a Regional, State, or Federal regulator:
You can use Affluent Effluent to introduce a sense of financial realism
into the planning process.The costs of operating and maintaining
conventional wastewater treatment plants can soar with increased energy and
chemical costs. These unexpected expenses can cut into operating and
maintenance budgets, and can result in reduced operating efficiency.
Reduced operating efficiency is a prime reason for failing to meet discharge
permit requirements. By definition, an alternative or innovative system
saves energy or operating dollars. Choosing an appropriate alternative
treatment option can reduce the burden of excessive operation and
maintenance costs while improving water quality.
Copies of Affluent Effluent for field personnel will enable them to
better discuss wastewater treatment alternatives with communities.
The film can be borrowed from the Innovative/Alternative (I/A)
Coordinator in your EPA Regional Office:
Charles R. Conway
Water Division
US EPA Region I
John F. Kennedy Federal Building
Boston, Massachusetts 02203
Jerry Ciotolla
Water Division
US EPA Region II
26 Federal Plaza
New York, New York 10278
Lee Murphy
Water Division
US EPA Region III
Curtis Building
6th & Walnut Streets
Philadelphia, Pennsylvania 19106
John Harkins
Water Division
US EPA Region IV
345 Courtland Street, N.E.
Atlanta, Georgia 30365
Charles Pycha
Water Division
US EPA Region V
230 South Dearborn Street
Chicago, Illinois 60604
Ancil Jones
Water Division
US EPA Region VI
First International Building
1201 Elm Street
11
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Mario Nuncio
Water Division
US EPA Region VII
324 East llth Street
Kansas City, Missouri 64106
Dallas, Texas 75270
Stan Smith
Water Division
US EPA Region VIII
1860 Lincoln Street
Denver, Colorado 80295
Paul Helliker
Water Division
US EPA Region IX
215 Fremont Street
San Francisco, California
Tom Johnson
Water Division
US EPA Region X
1200 6th Avenue
Seattle, Washington 98101
94105
The film is also available for rental or purchase. For further
information about buying your own copy or renting a print, please write to:
WATER FILMS, 1509 Phoenix Road, Phoenix, MD 21131
111
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ONSITE AND SMALL SYSTEMS
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ONSITE WASTEWATER MANAGEMENT PROGRAM
STINSON BEACH, CA What began as a
renovation
program is now a
model preventive maintenance program
for small towns that prefer to
control the use of septic systems
rather than investing in costly,
complex, and often unnecessary,
central sewage and treatment systems.
One of the simplest, least
expensive methods of wastewater
treatment is the septic tank/
leachfield. It is the most common
onsite system, used by about
one-quarter of the nation's housing
units. The septic system, however,
is all too often viewed as a
makeshift, temporary solution for
new communities that have not yet
developed a sophisticated sewage
infrastructure.
From 1950 to 1970 approximately
10 million homes converted from
onsite systems to sewers and
centralized treatment. Millions of
dollars have been needlessly spent
because communities have converted
septic systems to sewers and central
treatment facilities without
adequately considering potentially
more cost-effective alternatives.
Failing septic systems are often
cited as justification to obtain
government grants to construct
sewers and central treatment
facilities. Because of the high
costs of sewers, however, problems
attributed to failures are only
corrected in one area at a
time—usually that area of the
community with failing systems and
large population. As other areas
of the community become more densely
populated, it becomes desirable
to extend sewer service. The sewer
service expansion is again justified
by failing systems and government
funds are again sought to correct
the problem.
Some towns, however, are
avoiding falling into this costly
pattern of development. They simply
attempt to renovate existing septic
systems and manage these systems so
they won't fail. Stinson Beach, a
town of some 1,200 persons in Marin
County, California, is one of those
towns. In the early 1960's, rapid
population growth was anticipated in
the area and developers began to
push for a centralized system. This
movement gained momentum when state
and county health departments
documented high col 1 form counts in
nearby Bolinas Lagoon. Since
coliform is a bacteria commonly
found in human waste, officials
blamed failing septic systems for
the pollution.
During the sixties, the Marin
County Board of Supervisors
authorized a countywide sewerage
master plan which grouped Stinson
Beach with its neighboring community
across the Bay. Several projects
were proposed, all based on
centralized treatment plants with
ultimate land and/or ocean
disposal. One of the proposed plans
called for pumping all of Stinson
Beach's wastewater to Bolinas and
then piping it out to sea. During
its journey, not only
would the waste cross a pristine
reef on the California coast, but
it would also cross the San Andreas
fault a total of twelve times. The
estimated cost was $9 million. The
town voted down the project.
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Several months later, the
Regional Water Quality Control
Board imposed a building moratorium
and gave Stinson Beach permission
to pursue land disposal solutions.
Andrea di Marco, past President
of the Stinson Beach County Water
District, summed up the path
Stinson Beach took toward finding a
solution to their wastewater
treatment problem: "We spent three
years scaling down, getting to
partial sewering, getting to spray
irrigation disposal. Had we not
bought the water company from one
of the big property owners, we
would never have discovered that
spray irrigation at the proposed
site would have destroyed the
community's water supply. Right
after that the community said,
'You'd better think of something
else."1
What they thought of, was
asking state Senator Peter Behr for
help in developing special
legislation enabling the water
district to manage, or regulate,
the existing onsite systems. At
the heart of the legislation is the
right of the Stinson Beach County
Water District to inspect privately
owned septic systems. The District
can enforce the repair or
replacement of any system that
fails to meet state, regional, or
local codes. The penalties for
violation are strict: fines up to
$500 and/or imprisonment up to 60
days, with each day constituting a
separate offense. A lien may be
placed on the property to insure
payment. The District also has the
option of shutting off the water
supply to households with failing
systems—a fairly simple, but very
effective procedure. In a few
cases the shut-off has been imposed.
To understand the regulations,
it is necessary to know a bit about
septic systems. Wastewater flows
from the home to a double chamber
tank approximately five feet deep,
four and a half feet wide and nine
feet long. The tank is set so that
its top is at least one foot below
the ground surface. The liquid
enters the larger of the two
chambers first. Here solid waste
(sludge) settles to the bottom and
lighter wastes and grease (scum)
float to the top. A mat of
bacteria within the tank helps to
break down (decompose) the solid
wastes into water and simpler
organic compounds. The system may
have to be pumped to remove sludge
as frequently as once every three
years, or less depending on home
owner maintenance and water use.
The liquid in the primary
chamber then flows through a baffle
near the top of the tank into a
secondary chamber which is smaller
in size. Lighter solids still
contained within the liquid settle
out in this compartment. From the
secondary chamber the liquid flows
through an outlet near the top of
this secondary tank to a diversion
valve which leads to the leach
fields. The diversion valve is
simply a mechanical means of
alternating the use of two leach
fields so that they go through a
load-rest cycle on a yearly basis.
Once in the leachfields the
liquid is cleansed by percolation
through gravel that surrounds the
pipes and then flows into the
soil. For the most part, all of
the flow, from tank to fields, is
accomplished by gravity. In cases
where this is not possible, and the
leachfields must be above the
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elevation of the septic tank, a
pump basin and pump are used to
elevate the liquid to the leach
fields.
A septic system which lasts 25
to 40 years may cost between $2,000
and $15,000 to install. This cost
will vary greatly according to
household size. Land may need to
be purchased for an offsite septic
system.
The Stinson Beach Onsite
Wastewater Management Program's
Rules and Regulations spell out, in
very specific terms, the materials
to be used for construction of a
septic system. The size of the
leachfield varies according to soil
type and the theoretical water
consumption of a household.
Setback requirements from build-
ings, property lines, surface
bodies of water and groundwater are
also defined. Variances are
permitted to some of these factors
with approval from the Regional
Water Quality Control Board. For
example, if a homeowner can prove
that through conservation methods
they use less water than the
standard, they may be given
permission to construct a modified
leachfield.
Residents are required to put
access boxes above their septic
tank manholes so that the inspector
can examine the functioning of the
system periodically. Since nearly
all of the septic systems predated
the maintenance program, many of
them were not advantageously placed
for installing the access boxes.
Some systems were located under
sidewalks or patios. The residents
were ingenious about building
attractive and inconspicious access
boxes.
Each system was inspected at
the outset of the program and then
reinspected every other year.
Less-than-perfect systems are
inspected more frequently. If a
system appears to be sluggish,
eroded, giving off odors, or
overflowing, a "Failed System
Investigation" is carried out to
determine the cause of the
malfunction. Where a malfunction
is verified a failed system
citation is issued. When a system
does not pass inspection it must be
repaired or replaced.
After a failed system citation
is issued the major responsibilty
for repairs or replacement lies
with the homeowner. The owner does
have a right to appeal the citation
at a public hearing, but if the
appeal is denied the owner has
about 135 days to submit a design,
find funding, and have the work
completed. There are a few
options. For example, if the
property owner is unable to pay, or
unwilling to carry out the repairs,
the district may carry out the
design and contracting. The
district will then contract for the
work and insure its reimbursement
by attaching a lien. Should the
leachfields be exhausted and the
homeowner not have enough property
for a new field, the district may
purchase land and, again, put a
lien on the user's property or
require installation of an
alternative system.
All the costs of maintaining
onsite systems are paid by the
users. To cover the costs of the
district's management expenses,
annual permit fees are budgeted on
a sliding scale. Nevertheless, the
costs are about one-quarter to
one-third that of installing even a
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partial centralized sewerage
system. (In 1982 monthly fees were
approximately $10.00.)
Stinson Beach had to fight for
the right to prove that septic
systems, when properly designed and
maintained, are an environmentally
sound, economical alternative
approach to wastewater treatment
and disposal. In addition to
upgrading existing septic systems,
Stinson Beach has installed seven
composting toilets with grey water
systems. These systems require
special monitoring by the district.
While Stinson Beach is still a
demonstration project, all
indicators point to success.
Ms. di Marco stresses a few
points for other communities which
are considering this approach.
"When community representatives
who are interested in onsite
wastewater management come to
me, I always ask them a series
of questions: How strong is
your zoning, your land use
management and your community
plan? Do you have a recent
soils geology analysis and an
accurate assessment of surface
and groundwater quality,
drainage and domestic or
agricultural water use
patterns? Is a local or county
public agency available to
assume full legal and
management responsibility for
the program?"
"If you don't have any of
these, you won't be ready to
write your program and
ordinances for two to three
years. A community already has
to have some sense of orderly
growth and land use control."
Ms. di Marco notes that county,
regional, and state administrations
must be cooperative, and their
codes for septic system design and
installation strict enough or they
may undermine the local effort.
With fully developed management
policies and ordinances in place, a
strong Board of Directors, manager
and staff, and a public education
program for system care and water
conservation, Stinson Beach has
proven that small communities can
successfully administer onsite
systems.
For more information contact:
Andrea G. di Marco
California Regional Water
Quality Control Board
San Francisco Bay Region
1111 Jackson Street
Room 6040
Oakland, CA 94607
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DIAGNOSING FAILING SEPTIC TANKS
MASHPEE, MA Mashpee, a small
town on Massa-
chussets' Cape
Cod, has opted for onsite waste-
water treatment because its
population is spread over a large
land area. As Charles Buckingham,
Town Public Health Official states:
"Towns the size of Mashpee and
with the resources of Mashpee
just can't generate the amount
of money that's necessary in
order to put in a sewage
plant. The solution for small
towns has got to be greater
care and greater restriction of
use of the soil and the land,
and maintenance of individual
septic systems. If we do run
into a bad situation with soil
conditions where septic systems
are in trouble, there are means
that you can take to correct
that on the site or adjacent to
the site for a lot cheaper than
going in and putting in a sewer
plant for $10 million which
will only serve a small area of
town."
There was evidence, however,
that septic systems near John's
Pond were not operating properly.
During the summer months fishermen
and homeowners noticed a greyish
green mass of algae moving through
the water. The algae was removed,
but the question remained, which
septic systems were polluting the
water with enough nitrogen to
encourage the algae growth?
Because nutrient rich septic system
effluent is diluted by pond water
it might take years before enough
vegetation develops in one spot to
pinpoint the source. But the town
of Mashpee did not want to wait for
the problem to become that ex-
treme. "You don't have too much
success asking homeowners how their
septic tanks work, because each of
them believes that his system is
perfect," noted Mr. Buckingham.
"It's always the neighbor down the
line whose system is causing the
trouble."
With that in mind the people of
Mashpee decided to try some new
equipment developed by Dr. William
B. Kerfoot: a septic leachate
detector called the "Septic
Snooper." With this tool it is
possible to track down a failing
system before it causes extensive
environmental damage.
Mashpee's inspection team rowed
out into John's Pond trailing the
"Snooper" in the water. The
detector scans for specific
pollutants typical to septic
systems. Whenever the needle
jumped on the chart recorder,
indicating a high level of
pollutants, samples were taken of
the surface water. On shore, a
well point probe was inserted into
the ground and another sample was
taken. Testing these two samples
would tell if pollutants were
coming from surface run-off or were
leaching from a septic tank into
the groundwater and into the pond.
If the snooper recorded a stream of
contaminants, but an isolated
groundwater plume could not be
found with a well point probe, it
was a clue to check the pond's
incoming streams for surface
run-off of pollutants.
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When test results indicated
that pollutants were flowing with
the groundwater the team went
ashore to track its source. A new
instrument recently developed by
Dr. Kerfoot, the groundwater flow
meter, allows even greater accuracy
in determining the source of
pollutants. When inserted into a
hole dug to groundwater level, the
groundwater flow meter uses a heat
pulse to measure both the speed and
direction of groundwater flow.
Prior to its invention, this kind
of measurement required painstaking
injections of dyes which had to be
tracked through wells. The old
method was slow and often
inconclusive.
With clear evidence in hand,
the town of Mashpee found that
residents were quite willing to
correct failing systems.
Dr. Kerfoot is enthusiastic about
the new equipment. "For the first
time, you actually can detect and
treat individual failures on a
one-to-one basis before they become
so large on a shoreline that they
lead to substantial degradation of
the individual lake."
Charles Buckingham, Town Health
Officer agreed, "I think we saved
the pond. This way we've
anticipated trouble before it got
too big. There's no way to replace
John's Pond. You can't pump it dry
and start all over again."
For additional information contact:
Dr. William B. Kerfoot
K-V Associates, Inc.
P.O. Box 574
281 Main Street
Falmouth, MA 02540
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CLUSTER SYSTEMS
OTTERTAIL Rothsay Camp
COUNTY, MN faced a problem
typical of
Minnesota's lakes region. A dozen
homes, mainly vacation homes, were
nested tightly between an access
road and Lake Li da's shoreline.
Most were equipped with old, rather
primitive onsite waste disposal
systems. Even those with good
septic tanks were experiencing
difficulty as their leach fields,
set too close to the waterfront,
became saturated and caused the
septic tanks to back up. The
residents also noticed a build-up
of plant growth in the lake and
realized their septic tank effluent
had become a pollutant. With too
little room on the individual plots
to create new leach fields,
residents resorted to carrying
their wastewater out of their homes
in buckets.
At about the same time, the
state and county placed controls on
shoreline wastewater management.
Rothsay Camp residents approached
the County Department of Land and
Resource management for assistance
in solving their problem and
complying with the new ordinances.
Rothsay Camp wanted an economical
solution which they found with help
from County Shore!and Manager
Malcolm Lee.
Since the Rothsay Camp Home
Owners Association owned 23 acres
of land which was used as open
space and a buffer zone, Lee
suggested that part of that
property could be used as a
communal leaching field. Each
homeowner was required to install
adequate size septic tanks. These
tanks were hooked into a collection
line which carried the effluent to
a pump, through a distribution box,
and into one of the several
trenches which made up the leaching
field.
Rothsay Camp is the first
example of a cluster system in the
county and perhaps in the country.
Mr. Lee reports that when the
system was designed, they found
contractors unwilling to bid
because nobody had experience with
such a project. Lee approached a
local hardware and plumbing
business, acted as general
contractor and oversaw the
construction himself.
The effluent from the septic
tanks feeds, by gravity, into a
four-inch trunk line which is
conveniently set into an old road
bed. One home with a basement
required a pump to tie into the
trunk line. Two main pumps then
pushed the effluent up to the
leaching field. Originally the
design included separate metering
for the electricity used by the
pumps. Since the amount of
electricity used was so small, they
decided to run the pumps on
electricity furnished by the last
home in the row. Every summer at
the association's annual picnic,
each household pays that homeowner
four dollars to cover the annual
operating expenses.
The residents of Rothsay Camp
check the system themselves. When
a tank needs cleaning, the individ-
ual owner pays for it. When a main
pump needs replacement, the
hardware store which built the
system installs a new pump and the
residents share the expense equally.
All residents signed a Deed of
Easement to permit construction,
operation and maintenance of a
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system that crosses their
individual properties. This deed
also obligates any future owners to
comply with the arrangement.
The cooperative system has
proven to be an extremely
economical, environmentally sound
approach. Construction costs,
including land, pipes, and pumps,
came to $481.17 per household. The
costs of additional septic tanks
were paid by the individual
homeowners. Both the common and
individual operating costs for
pumps, electricity, and cleaning
the septic tanks are minimal.
The county now requires that
every waterfront property be
certified to indicate compliance
with the Shoreland Management
Ordinance. This certification can
increase the value of a property by
as much as $10,000 when the
property is sold. Rothsay Camp's
willingness to innovate meant that
they were able to comply with the
regulations at a minimal cost.
Naturally, that cost has increased
a bit over the past several years,
but even at $800 per household this
approach is more economical than
other methods considered to solve
similar problems.
"The techniques that Ottertail
County developed at Rothsay Camp
proved very valuable to a large
project elsewhere in the County.
At Ottertail Lake residents were
planning to run a sewer line all
the way around the Lake, at a cost
of about $10 million.
A USEPA Region V Environmental
Impact Statement (EIS), developed
because of the high costs and
social impacts of the proposal,
discovered that only 4% of the
deterioration in the surrounding
water was from human waste. The
rest was due to fertilizer runoff
from surrounding farms. Building
an expensive sewer and treatment
plant might not improve water
quality significantly. According
to the EIS, localized public health
problems and nutrient "hot spots"
could be resolved for barely one
third the cost of the original
proposal. This could be done by
repair and upgrading of existing
on-site systems and selective use
of the same kinds of cluster
systems built at Rothsay's camp.
In September 1981, Ottertail County
received a federal and State grant
for actual design work for this
alternative.
Meanwhile, there are already
dozens of houses throughout
Ottertail County using cluster
systems. Visitors from as far away
as Nova Scotia have come to examine
this cost-effective wastewater
treatment system.
For more information contact:
Malcolm Lee
Land and Resource Management
Ottertail County Court House
Fergus Falls, MN 56537
I & A Coordinator
Water Division
U. S. EPA Region V
230 South Dearborn Street
Chicago, IL 60604
(Copies of the Environmental Impact
Statement developed by EPA Region V
for the Ottertail project titled
"Alternative Waste Treatment
Systems for Rural Lake Projects"
are available on request from the
I&A coordinator, USEPA Region V.)
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MOUND SYSTEMS
ORONO, MN In the late 1970's
Orono, Minnesota
faced the question of
whether to extend their central
sewage system into the town's
surrounding rural areas. As one of
their brochures indicates, they
realized the decision could affect
the quality of life in Orono:
"To extend sewers into rural
Orono, estimates are that each
homeowner would pay $10,000 or
more per acre. This cost, as
in other cities, may then force
subdivision of the land into
smaller lot sizes in order to
reduce the individual homeowner
costs. The rural lifestyle
would disappear to be replaced
by higher housing density,
increased traffic, increased
needs for roads, schools and
other city services, and in the
end increased taxes. Although
not so apparent, the increased
housing density would adversely
affect the environment by re-
ducing ground water reserves,
eliminating wildlife habitats,
and decreasing storm water
runoff quality. Lake Minne-
tonka would never again be the
same."
Although specific septic system
design and construction standards
had been adopted as far back as
1961, the discharge of inadequately
treated sewage from some of these
systems to the ground surface was
not completely remedied. In April
1978, the Orono City Council
adopted additional regulations to
ensure that onsite sewage treat-
ment systems would be properly
installed and properly maintained.
Orono established specific design
and maintenance regulations,
including an inspection program,
licensing for construction and
pumping contractors, and
centralized records on the
maintenance of each onsite system.
The Orono regulation included a
provision for alternative and
innovative sewage treatment systems
where the soil was not suited to
the typical leaching field. Much
of the soil in Orono contains too
much clay to allow septic tank
effluent to percolate into the soil
from deep trenches. The clay soil
also tends to have high seasonally
saturated conditions, which also
will not allow the installation of
typical leaching fields. A
leaching field system installed in
a clayey soil with high seasonally
saturated conditions would cause
inadequately treated effluent to
surface and cause a health hazard.
To solve the soil problem, Orono
made use of an alternative system
described in the Minnesota State
Guidelines for Sewage Systems. The
specifications for the sewage
treatment mound were adapted from
research at the University of
Wisconsin Small Scale Waste
Management Project. They utilized
the naturally more permeable
surface soil layers by building the
rock bed of the leach field above
the natural soil surface.
To build the mound, an area of
land, (about 35' X 65' for a
typical 3-bedroom home), is plowed
or disked to loosen the upper foot
of top soil. The selected area can
follow the shape of the property,
but should not slope more than 12%
(3% for heavy clay soil) or be
located in depressions or drainage
-------
ways. A level layer of sand at
least 12" thick is laid down and
followed by 9" of clean, igneous
rock 3/4" to 2 1/2" diameter.
Distribution pipes, connected to
the pump station, are placed over
this rock. The 1 1/2" to 2" pipe
from the pump station connects to a
system of parallel 1 1/2" pipes
perforated with 1/4" holes every 3'
and capped at the ends. Another 2"
of rock is placed over the top of
the perforated laterals and the
rock is covered with 3" or 4" of
marsh hay or straw. A sandy loam
fill is placed over the rock bed,
tapering from 1' deep in the center
to 6" at the edges of the rock
bed. The entire mound is covered
with 6" of top soil and planted
with grass. The site for the mound
can usually be selected to fit into
the landscaping plan.
To insure distribution of
effluent over the entire rock bed,
a dosing pump is used. The loading
rate through the pressurized
distribution system is designed to
provide unsaturated flow through
the sand bed, resulting in an
aerobic environment which aids in
sewage treatment. The pumping
station receives the septic tank
effluent and discharges it at a
rate of at least 30 gallons per
minute for a typical 3-bedroom
home. An alarm is installed to
warn of pump failure, and the
station is capable of storing 1
day's sewage in case such a failure
should happen.
Breakdown of pump control
switches, a problem experienced in
some of the first mound systems, is
no longer a major problem.
Significant advances have been made
in the design and dependability of
these switches. They are typically
no longer contained in the pump
case, but rather function as an
auxilliary unit. Either the pump
or the switch can be replaced
independently in case of failure.
Equipping the pumping station
control, providing an alarm,
storage space, and a manhole access
for servicing, has made this unit a
dependable part of the sewage
system.
Orono's initiative in using the
mound sewage system is one more
example to show that onsite sewage
treatment systems are a cost
effective and environmentally sound
alternative to centralized sewage
systems.
Addendum:
While mound sytems are more
expensive than conventional
drainfields, they are usually much
less expensive than sewers.
A generic cost comparison per
dwelling is:
Septic tank
with drainfield
Septic Tank
with Mound
$1500 to $4500
$3500 to $6000
Conventional Sewers $6000 to $12,000
and Treatment
Overall project savings may
often be realized because with
onsite upgrading every house may
not need a totally new septic tank
and drainfield or mound.
10
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For further Information contact:
Roger E. Machmeier
Extension Agricultural Engineer
University of Minnesota
St. Paul, MN 55108
Michael P. Gaffron
Septic System Inspector
City of Orono
P.O. Box 66
Crystal, Bay, MN 55323
Perry Beaton, Chief
Facilities Section
Division of Water Quality
Minnesota Pollution Control Agency
1935 West County Road, B-2
Roseville, MN 55113
I&A Coordinator
Water Division
U.S. EPA Region V
230 South Dearborn Street
Chicago, IL 60604
11
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PRESSURE SEWERS
MANILA, CA Manila is a small
northern California
community situated on
an isolated peninsula adjacent to
Humboldt Bay. Manila was facing
severe health and environmental
hazards created by a combination of
failing septic tanks, a dense
population, and high groundwater.
Virgil McNutt, Manager of Manila
Community Services District,
described just how serious the
problem was:
"We were polluting, there's no
doubt about it. I've seen 50 to
70 septic tanks buried under
water for weeks at a time and
then the runoff--the whole area
would be polluted with the
effluent from these tanks. Then
it runs off down the ditches.
Very foul odor for weeks
afterwards. Actually, it boiled
down to, if you saw a nice, big
patch of blackberries growing,
you could bet that there was a
failed septic tank there."
The search for a solution began
in 1972. A conventional sewage
collection and treatment system was
considered, but even with Federal
grants, the estimated $30 per month
user charge would be too high for
many low income households. The
system's high cost was largely due to
Manila's geological location. High
groundwater and sandy soils require
pumping the ground dry and shoring
trenches to install sewer pipes. In
addition the undulating terrain makes
it necessary to sink these pipes some
twenty feet to insure gravity flow.
In spite of the severity of
Manila's water quality problem, an
earnest search for an alternative to
the failing septic systems did not
begin until 1977. Even then regional
authorities were pressuring Manila to
wait for the construction of a
planned regional wastewater treatment
facility. Meanwhile, Mr. McNutt
learned of promising alternatives
being used experimentally in New York
State. When he first presented the
concept of a low-pressure sewage
system, many people unfamiliar with
these systems questioned their
effectiveness.
A study of Manila sewer problems
and the feasibility of possible
alternative solutions revealed the
potential advantages of a pressure
sewer system. The California State
Water Resources Control Board was
eager to conduct a demonstration
project on a promising alternative:
a low-pressure sewer system. The
State Board was willing to cover all
costs of the experiment, and one of
their reports succinctly explains why:
"Presently (1980) $550 million of
local, State and Federal funds is
committed for the construction of
collection systems and treatment
facilities in 304 California
communities. Approximately
three-fourths ($400 million) of
this money will be spent for
construction of collection
systems. In 25 percent of the
communities it is conservatively
estimated that a low pressure
sewer system would be signif-
icantly more (i.e., greater than
50 percent) cost-effective than a
gravity collection system. This
represents a savings of $50
million..."
Manila qualified for this program
for several reasons:
12
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o There was a well defined
health, environmental, and
economic need in the community;
o With 350 residences, the
community was small enough to
fit within the project's
budget, yet large enough to
allow for experimental
variations in design, and to
provide adequate data for
analyzing the approach;
o More importantly, the
geological features of Manila
rendered a conventional
gravity sewer prohibitively
expensive.
After consideration of several
other alternatives, the community and
the State chose the low-pressure
sewage system for demonstration. The
first component of Manila's system is
an onsite septic tank. Concrete and
fiberglass tanks of varying sizes
have been installed on individual
lots. In some cases, two to four
homes feed into the same tank. In
order to ease installation, plot
plans of each property were drawn so
that residents could take part in
deciding on tank location. This
approach helped prevent tensions
which might have arisen between the
utility and the residents. Sludge
removal is considered part of the
standard system maintenance and is
managed by the Community Services
District.
A pump inside each tank forces
the partially treated effluent into
the collector system. Three
different brands of pumps ranging
from 1/3 to 1 horsepower were
tested. The pumps represent the
major maintenance task for the
district's staff. One problem
encountered was that earwigs (small
insects) were attracted to the switch
breakers. When the breaker tried to
close, the earwig got caught,
blocking the contact. Pumps are now
equipped with failure alarms and each
tank is large enough to accommodate
storage of one day's sewage in case
of pump failure.
Because the effluent pumped from
the septic tanks does not contain
solids, the pipes in this system are
small: 1-1/4 to 1-1/2 inches for
connector lines; 3 to 6 inches for
mains. These small pipes are the
great attraction of low pressure
systems. Not only are they less
expensive than gravity mains, but
they are installed only 2-1/2 to 5
feet below the surface — a
substantially less costly install-
ation process than digging down 20
feet for gravity mains. The system
design also allows for regular
cleaning and inspection of main
pipes. As a safety measure, a
stronger-than-necessary pipe was used
and an extra encasement covers pipes
which cross or parallel water mains.
The terminal for the system is a
pump station, a wet well, and a
leaching field located on a high sand
dune. The wet well essentially acts
as a holding tank, smoothing the
peaks in daily flow so that effluent
is applied to the field at an even
rate. To help control odors air is
drawn out of the wet wel1, pushed
through an activated carbon filter,
and discharged through a roof stack.
As this is a demonstration project,
the station also includes substantial
instrumentation to gather research
data. The three acre leaching field
is divided into four quadrants to
allow alternate rest periods. The
leaching lines (1 inch perforated PVC
pipe) are set in a one foot deep bed
of gravel and covered with a layer of
plastic and three feet of sand.
13
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Below the pipes, approximately 30
feet of sand filter and polish the
effluent before it enters the ground
water table.
Capital investment for the Manila
project was $5,080 per connection;
this includes on-lot facility costs
of about $3,851 per connection, but
does not include special testing
equipment to gather research data.
If a gravity system had been
installed, pumping stations alone
would have cost one-third of the
total capital costs of the low
pressure system.
Households are charged a base
rate of $7.50 monthly for the first
500 cubic feet of water used and
$0.40 for each additional 100 cubic
feet of water used. The average
monthly cost per connection is
approximately $8.00.
David Tollefson of Uinzler &
Kelly Consulting Engineers sums up
pressure sewers' applicability for
other communities:
"Pressure sewers are not going to
replace gravity sewers because
where you have conditions that
accommodate a gravity sewer,
there's nothing cheaper. Where
you have unique problems though,
like bedrock; high ground water;
undulating terrain where a large
number of lift stations; or rural
communities that are spread out;
gravity sewers just wouldn't be
practical. I think pressure
sewers are certainly going to be
applied in the future. They're
also going to be used in housing
development communities where
development is going to occur
over some long periods of time
and they're not going to want to
spend the up-front money of putting
in a huge gravity sewer line right
off the bat. They will develop
community pressure sewers."
For further information contact:
Winzler & Kelly
Consulting Engineers
633 Third Street
Eureka, CA 95501
(707) 4443-8326
I&A Coordinator
Water Division
US EPA Region IX
215 Fremont Street
San Francisco, CA 94105
James Bennett
California State Water
Resources Control Board
P.O. Box 100
Sacramento, CA 95801
14
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CONVENTIONAL TREATMENT
WITH ALTERNATIVE OR INNOVATIVE ADD-ONS
-------
GOOD OPERATION AND MAINTENANCE
PORTLAND, OR. Government studies
have shown that
many treatment
plants are not meeting their
discharge permit requirements. These
requirements are established in a
plant's discharge permit by the
National Pollutant Discharge
Elimination System (NPDES). There
are three problem areas which
dramatically affect a plant's ability
to treat wastewater efficiently and
for the least cost.
Substances in the influent that
are incompatible with the treatment
system or which can destroy the
working bacteria of the treatment
plant, are common causes of discharge
permit violations. This can result
when an industry discharges toxic
wastes into the sewer system.
Operation and maintenance
deficiencies resulting from
undertrained operators, insufficient
staffing, or poorly maintained
equipment, are other prevalent
reasons for treatment plant problems.
In contrast to many plants in the
U.S., Portland, Oregon's wastewater
treatment plants are considered among
the most effective in the country.
Not surprisingly, Portland officials
have given special attention to the
three problem areas.
Portland strictly monitors sewage
treatment plant influent. Industries
that discharge wastes that place an
undue burden on the treatment plant
(ie., high biochemical oxygen demand
(BOD) and suspended solids) pay a
surcharge for the additional load
placed on the plants. Industries
that dump incompatible industrial
wastes like heavy metals acids or
other unacceptable substances, are
required to pretreat their wastewater
before discharge to the sewage system-
About three-quarters of a million
dollars annually is collected from
the Portland industrial program.
This pays for monitoring, additional
treatment costs and also acts as an
incentive for industry to initiate
recovery or pre-treatment of toxic
materials in the wastewater.
To improve the design of
treatment facilities, plant personnel
work with engineers during the
planning stages. This policy has
several positive effects on the
system. First, plant staff can often
identify design problems which the
engineer may have overlooked or may
not be aware of. For example, plant
personnel suggested an innovative
design for digester floors to improve
the consistency in concentration of
sludge solids being drawn from a
digester. Another suggestion was
made to allow easier access to the
digester interior for maintenance
personnel.
These, and other suggestions were
incorporated into the design of
additional digesters at Portland.
Second, a cooperative effort enables
the engineer to design plant
characteristics responsive to the
user's needs. Finally, Portland has
found that involving plant staff in
the planning stages improves their
understanding of the system and the
engineer's intent. This in turn
helps improve staff morale and
motivation.
15
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Portland has also placed a very
strong emphasis on all aspect's of
operation and maintenance. They
exercise particular care in hiring
and training well qualified
operators. The minimum requirement
for hiring an operator is either
completion of a formal training
program, or one year of on-the-job
experience in a treatment plant.
The supervisory staff has, in the
past, conducted year-long training
programs for employees. Another
policy which improves performance
is the rotation of operators to
different stations. An employee
who understands the system as a
whole seems to work more
efficiently and enthusiastically.
Portland's top management
emphasizes high morale both in
selecting their staff and working
with them.
Portland's wastewater system,
serving a population equivalent to
over.600,000 is comprised of two
activated sludge plants, (one 100
MGD plant, and one 8.3 MGD plant)
and 52 pumping stations treating
31.5 billion gallons of wastewater
per year. The annual operating
budget is about $6 million. The
City Council has guaranteed the
plants' performance by supplying
adequate necessary resources to
operate and maintain them well.
For more information contact;
Howard H. Harris
Superintendent
Bureau of Wastewater
Treatment
5001 N. Columbia Boulevard
Portland, OR 97203
16
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URBAN IRRIGATION
ST. PETERSBURG, FL. St. Peters-
burg is a
large city
built on a peninsula, jutting into
the Gulf of Mexico and framing
Tampa Bay. While much of Florida
is blessed with enough potable
water, St. Petersburg's wells
brought up sea water or water
smelling of sulfur which could only
be used for limited irrigation
purposes. By 1928 the city was
water-scarce and still rapidly
growing. Forced to purchase land/
water rights in neighboring
counties, the city was soon
involved in a tri-county water
war. A regional water authority
was establishied to settle the
disputes and provide planning, but
St. Petersburg recognized that
fresh water would always be a
precious commodity.
Because of this chronic
shortage, the city limited the use
of potable water for irrigation.
Regulation posed serious
landscaping problems for office
buildings, residential complexes,
and recreational areas such as golf
courses and parks during times of
drought.
Meanwhile in 1971, the State
imposed strict requirements on the
treatment of sewage effluent dis-
charged into Tampa Bay and its
tributaries. Although St. Peters-
burg already had extensive,
sophisticated secondary treatment
plants in place, they began re-
search and planning for an advanced
wastewater treatment (AT) plant.
Investigators found that the most
difficult pollutant element to
remove was the nutrient level in
the effluent. Removing nutrients
like nitrogen and phosphorus would
exponentially increase treatment
costs. To build a plant that would
meet the State's new discharge
requirements, an additional $40
million capital investment would be
needed.
If St. Petersburg was going to
spend so much money to produce high
quality effluent, why throw it
away? Why not put it to good use?
Since there was a high demand for
irrigation water, the effluent
could be used in this manner. The
benefits of recycling were very
attractive. It would: (1) lower
the cost of wastewater treatment by
eliminating the need for nutrient
removal; (2) provide water for
irrigation; (3) eliminate all
effluent discharge into the bay;
and, (4) renew the groundwater
supply. The city could charge
users for the recycled water to
cover some of their treatment
expenses. In St. Petersburg the
effluent goes through a fairly
standard process of grit removal,
aeration, clarification and
chlorination.
In the mid 1970's the city made
a decision to recycle the treated
wastewater rather than continue
discharging into Tampa Bay.
Instead of paying for construction
and operation of costly nutrient
removal facilities, the nutrients
remain in the effluent and now
fertilize the irrigated vegetation.
Major modifications made to the
plant were the addition of multi-
media filters and alum. A
retention basin was built and
additional chlorination added when
quality control demands it.
17
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Once the wastewater is treated,
the water is distributed through a
system of pipes to irrigation
sites. To prevent the mixing of
potable and recycled water, the
separate distribution pipes and
hydrants are color coded. In spite
of the fact that the water is
constantly tested, and is actually
cleaner than some fresh water,
users are advised not to drink it.
When the supply exceeds both demand
and storage capacity, the excess is
injected into underground wells.
The cost for the recycling
system was $19 million — a big
bill, but less than half the cost
of the AT alternative. St.
Petersburg is particularly proud of
the recognition its recycling
system has won. St. Petersburg's
system was selected by the National
Society of Professional Engineer's
as one of the "Ten Outstanding
Engineering Achievements of 1976"
along with the Viking Mars Landing
Spacecraft.
The city is now irrigating
2,000 acres of public and private
green space with water that once
was discharged directly into Tampa
Bay. Assuming that half the water
is sold to commercial customers at
the going rate of $0.03 per cubic
meter, the program generates about
$40,000 in revenue per year. The
problem St. Petersburg now faces is
extending the system to meet
demand.
One golf course landscaper's
story indicates how successfully
the program has solved the local
irrigation problems. Before the
golf course received recycled water
three years ago, the landscaper had
to rely on lake water (which
accumulated from street drainage)
for irrigation. The ponds tended
to mix weed seeds into the water
supply, fouling both the irrigation
system and the greens. After
installation of the water recycle
system the landscaper has a regular
adequate supply of water which has
allowed him to cut fertilization in
half and has fewer maintenance
problems. There are no odor
problems.
St. Petersburg's program is an
experiment on a large scale.
Recognizing the city's success, the
State is trying to establish a set
of standards for the use of
recycled water in urban settings,
for crop irrigation, and for
industrial use. Visitors from all
over the world come to invest-
igate the possibility of recycling
as a solution to their water
shortage and wastewater management
problems. The experts in St.
Petersburg advise that in highly
industrialized areas the system may
require additional precautions,
more testing, and more
pretreatment, but otherwise they
urge any water-scarce city to
consider recycling.
For more information contact;
William Johnson
Director
Public Utilities Division
City of St. Petersburg
1635 Third Avenue, North
St. Petersburg, FL 33713
18
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SPRAY IRRIGATION OF CROPS
PAYNESVILLE, MN. Paynesville is a
town of 1,200
persons, situated
amidst the lakes, corn fields, and
dairy farms of rural Minnesota. The
people of Paynesville are proud to
have created an economical, environ-
mentally sound system for treating
their community's wastewater. Their
system is both esthetic and inexpen-
sive, and provides benefits to
farmers and townspeople alike.
The center of Paynesville has a
sewer system which feeds into a
series of four ponds, often called
lagoons. The four foot deep ponds
can treat 425,000 gallons of
wastewater per day. The only
mechanical part of the system is a
pump which brings the water from the
town to the ponds. Nature does the
rest: sun, wind and bacteria break
down the waste. The flat Minnesota
terrain, as well as the wind
direction and constancy, are
particularly conducive to this
biological process.
To keep the edges of the ponds
clear of excessive growth, sheep are
allowed to graze the area. This
saves the town the trouble of
mowing. The ponds also play host to
ducks, herons, swans, and other water
fowl. The lagoons look more like a
recreational area than a wastewater
plant. There is no sludge problem
and there are no odors, except for a
few days in the spring. The system
requires only one man working part-
time to maintain. The only repairs
necessary have been patches for a few
muskrat holes made in the retaining
walls. The typical user's sewage
treatment bill comes to $3.50 a month.
Up until a few years ago, the
town's treated effluent was allowed
to flow from the ponds to a nearby
river and to continue on its way
through the region's extensive
waterways. Even though the effluent
met all of the State's standards for
purity, it was rich in nitrates and
particularly high in phosphates.
This combination promoted a nutrient
overload in the lakes and a build-up
of unwanted plant growth, a form of
pollution.
Meanwhile, the hot, dry winds of
summer were ruining the local dairy
farmers' feed crops. By August corn-
fields were parched and nearly
useless. At a cost of $80 per acre
(half of which was required to pump
groundwater to the surface) farmers
could not afford irrigation. One
farmer, Art Voss, whose land was near
the treatment ponds, looked at the
thousands of gallons pouring from the
ponds into the river with envy, and a
touch of skepticism.
Fortunately at the same time
Paynesville's mayor was looking to
the farmers for a lesson in resource
management. "The manure from 100
dairy cows amounts to a staggering
amount of waste. Farmers have an
excellent method waste disposal; they
haul it out into the field, plow it
down, and grow crops. It's a
continuous cycle. I felt that if the
farmer can do it, why can't we?"
Paynesville has no heavy
industry. There are few, if any,
heavy metals or harmful chemicals in
the effluent, and therefore, it would
not be harmful to crops or the
livestock to which the crops are
fed. Also no chemicals are used in
19
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treating the town's wastewater. The
water from the treatment ponds (when
tested by the State's Department of
Public Health) has been declared
virtually free of pathogens. With
these facts in mind, the town decided
to try using its effluent for feed
crop irrigation.
The mayor and irrigation
specialists developed a plan to
recycle the wastewater and called for
bids. A technical difficulty over
the bidding nearly aborted the
project until Art Voss, a local
fanner who lived near the pond,
volunteered to use his own equipment
to apply the effluent to his crops.
When, after a few days of application
the plants showed no indication of
brown spots or other damage, Art Voss
began irrigating his own fields.
The experiment proved tremend-
ously successful. Art Voss' crop
yield, which averaged 70 to 80
bushels of corn per acre and dropped
to near nothing in dry years, jumped
to 150 bushels per acre following
irrigation with the treated waste-
water. Of course any irrigation
would have improved the yield, but
Voss felt there were particular
benefits to using the treated
effluent from the ponds. First, the
ponds were already at surface level
which saved deep well pumping costs.
Second, effluent containing
phosphorus and nitrogen contributed
to fertilization of the crops.
Finally, the pond water was warm and
did not shock the plants.
Paynesville realizes several
additional benefits from this system
besides protecting their lakes. Use
of the pond water for irrigation
helps to preserve the groundwater
supply. In addition, fanners
irrigating with wastewater effluent
increase their production of feed and
silage.
Recognizing Art Voss' benefits
from use of the effluent, other
farmers were quick to demand access
to the wastewater ponds. They were
willing to do most anything to get
the water, offering use of their own
equipment to pipe the water to their
own property. Four years later, 800
to 1000 acres of land producing
animal feed crops are being irrigated
with effluent water.
Having proven the program sound,
Paynesville was granted EPA funds to
extend the system. The town will
install pipes to carry the water from
the ponds to outlying farms.
Irrigation equipment will be
purchased by the town and leased to
the fanners. They intend to charge
$25 per acre irrigated per year.
This includes costs for water, power
and equipment usage. It is
anticipated that this fee will more
than cover the systems' operating
expenses. At the $80 per acre price
for irrigation with groundwater, the
farmers consider the effluent a
bargain; and the charges offset the
cost of wastewater treatment for the
town.
Since the water is used only for
irrigation during the growing season,
Paynesville continues to discharge
effluent from the ponds into a river
during the winter months. The EPA
funds will enable additional ponds to
be built, increasing the holding
capacity and, therefore, the
irrigation water supply.
The people of Paynesville are
proud of this system. They created
it themselves from a few good ideas,
a willingness to take risks, and
enthusiasm. It is not only aesthetic
20
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and inexpensive, but has an economic
advantage for the farmers and the
community as a whole. There are
relatively few conditions that would
keep other communities from
considering a similar system. The
basic requirements are inexpensive
open land near the town for ponds, a
controllable level of industrial
waste predominantly flat terrain, and
adequate feed-crop farming requiring
irrigation within a convenient
distance from the ponds.
For more information contact:
Donald W. Jackson
City Clerk
Town Hall
Paynesville, MN 56362
I & A Coordinator
Water Division
U.S. EPA Region V
230 South Dearborn Street
Chicago, IL 60604
21
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LAND RECLAMATION/WILDLIFE ENHANCEMENT
MARTINEZ, CA Amidst the fac-
tories, smoke
stacks, and
highways of an industrial park in
Martinez, California, it is
remarkable to find a marshland
hosting herons, shorebirds, wild
ducks, and a wide range of wild-
life. It is even more remarkable to
learn that this marsh was created by
the Mt. View Sanitary District in an
industrial area and is fed by efflu-
ent from their wastewater treatment
plant.
The Martinez high-rate trickling
filter plant serves a population of
about 12,000. Average daily flow is
approximately 800,000 gallons. In
1974 the sanitary district was
advised by the State that they could
no longer discharge effluent into a
tributary to the San Francisco Bay.
There were two conventional solu-
tions open to them: invest
approximately 6.5 million dollars to
hook into a regional treatment
plant, or spend 2.5 million dollars
on pipes and pumps to carry the
effluent one and a half miles away
for deepwater discharge directly
into the bay. But Mt. View's
administration saw another option.
Next to the plant was an area of
brackish marsh which had been
drained many years before for
development purposes. Mt. View
officials thought it possible to
foster a mutually beneficial
relationship with nature. If they
could create a new wetlands area
using their treatment plant's
effluent, perhaps the quality of the
effluent would be improved by the
natural biological cycles which
occur in a healthy marsh. While the
district could not guarantee a
higher quality effluent, the State's
administration was receptive to the
idea for several reasons. Since the
turn of the century, approximately
70% of California's wetlands have
been lost to draining and filling.
Habitat for literally hundreds of
types of flora and fauna was
diminishing. A major link in the
ecological chain was slowly
disappearing from the west coast.
California, experiencing chronic
water shortages, also wished to
encourage secondary use of water
supplies. So, the State allowed
Mt. View to proceed with their
experiment.
The basic idea, explained Roy
Brown, District .Superintendent, was
wildlife enhancement of an urban/
industrial area. They wanted to get
away from the concrete, asphalt and
steel approach to wastewater
treatment, and return to using the
natural ecological chain. In
addition to providing wildlife
habitat, the project had a strong
education potential. It provided an
opportunity to study birds, mammals,
amphibians, insects and smaller
organisms in a natural setting.
About twenty acres of wetlands
were created and divided into
several shallow and deeper water
areas so that various conditions
could be studied. The combination
of elements was found to be most
effective in promoting wildlife
habitat and, to a lesser extent,
improving the quality of the water.
First, there must be a large enough
span of open water that birds in
flight could be attracted to it.
Within the pond area, several small
islands were built to give the birds
safe nesting areas. About a third
of the wetland surface is covered
with emergent vegetation (tall
22
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grasses which grow out of the
water). Some 72 species of plants
grow of their own accord, providing
food, shelter, and nesting for birds
and animals. The vegetation also
helps prevent erosion. The
biologist investigated methods to
increase the food supply. With the
cooperation of the California State
Fish and Game Department, an
additional 2.5 acres of seed pro-
ducing vegetation were planted.
In addition to the open water
and plants, an artificial third
element was introduced. Ecofloats
provide breeding grounds for the
small aquatic organisms that help
purify the water. The ecofloats
consist of little sacks, made from
nylon mesh containing redwood bark,
which are suspended from the float
into the top 6 to 10 inches of
water. These provide a surface for
the aquatic micro-organisms. Some
of the floats have little windmills
that mix the pond water from top to
bottom and circulate nutrients.
The primary food chain begins
with micro-organisms in the water.
Small aquatic animals feed on these
organisms and on the organic matter
suspended in the water. Thirty-four
different species of invertebrates
living in the wetlands comprise part
of the secondary food chain. Dif-
ferent types of fish, including
mosquito fish, were introduced to
reduce the mosquito population.
There are also ninety species of
birds, some of them quite rare, that
either live in or stop at the wet-
lands during migration. Finally,
another nineteen species of mammals,
amphibians, and reptiles have found
their way into the man-made wetlands.
There is little question that
Mt. View has been very successful in
creating a wildlife habitat. In
fact, the local Audubon Society gave
the district an award for its work,
declaring the wetlands one of the
best birding areas in the county.
The site is popular with all sorts
of educational groups.
On the journey through the
marsh, organic constituents in the
plant effluent are reduced by
harmless aquatic organisms. Algae
give the water a greenish tinge
which, although unattractive, is
environmentally safe. There is
some reduction in nitrates and
phosphates but since nutrient use by
plants is tied to the natural
growing seasons, it is not as
consistent a reduction as that
achieved by chemical or mechanical
treatment.
Additional experiments are
underway using treated effluent from
the treatment plant to irrigate
trees. This process aids in
purifying the effluent by reducing
the nutrients and algae. There are
initial indications that the rich
water encourages the trees to grow
very quickly. On a large scale, it
may be possible to reap a profitable
cash crop of redwoods.
It is almost impossible to place
a dollar value on the wildlife
habitat created at Mt. View. The
capital cost was $300,000 and the
operation and maintenance run about
$1,200 per year, plus salaries for
about 10 hours of maintenance and 15
hours of monitoring and management
weekly.
Mr. Brown advises that an
artificial marsh of this type is
best suited for sites with marginal
quality land and a water course that
will carry the effluent off for
final discharge. Since there could
be some problems with mosquitos, it
is best located away from a resi-
23
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dential area or else institute
effective mosquito control
procedures.
For more information contact:
Roy Brown
Superintendent
Mt. View Sanitary District
P.O. Box 2366
Martinez, CA 94553
24
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SLUDGE COMPOSTING
DURHAM, NH When the selectmen of
Durham, New Hampshire
began planning a
secondary wastewater treatment
plant, they approached the problem
with unusual foresight. At the
time, the existing primary plant was
producing 15 cubic yards of wet
sludge per week. It was being
dumped into a make-shift landfill
and causing handling problems and
offensive odors. Since the dump was
near a river, they were also con-
cerned about polluting the water.
In addition, since the town was
considering the construction of a
new secondary treatment plant that
would produce twice as much sludge
as the primary plant, they were in
need of a solution for sludge
disposal.
Incineration of the sludge was
considered, but New England's high
fuel costs made that approach
impractical. Landfill was another
possibility, but purchasing land
outside the town was too expensive.
The town decided to experiment
with composting. In the small town
of 6,000 permanent and 12,000
college residents, there was a
strong feeling that it made sense to
complete the cycle of wastewater
treatment by returning a viable
product to the land rather than
wasting it through incineration or
landfill.
Composting is a very natural
process. The bacteria, which are
abundant in sludge, digest the
sludge and produce a humus-like
material. They need food, water,
and air to break down the sludge.
The first two elements are amply
supplied by the sludge, but the air
must be introduced artificially.
Even before the start of the
project, Durham recognized that to
be successful, composting must be
mechanized, economically feasible,
and operational year-round. New
England's harsh weather conditions
heightened the importance of this
last factor. The town carried out a
pilot project to determine if
composting could meet these
criteria. This experiment was not
only a success, but provided several
valuable lessons in designing a
permanent composting system.
The Durham pilot project began
on a one-acre lot several miles from
the treatment plant. It was quickly
realized that transporting the
sludge was a messy job that used
fuel, tied up trucks and labor.
They decided that the permanent site
should be adjacent to the new plant
for operational efficiency and in
the interest of cost-effectiveness.
The next lesson concerned the work
surface. Initially, a layer of
gravel was used for a composting
pad, but the gravel caused
problems. It was a difficult
surface to work on and the stones
tended to mix into the compost. A
250'x 152' concrete pad has since
been installed. This pad is large
enough to build compost piles for a
two-month period and still allow
work room for handling. It has a
built-in drain so that any liquid
runoff from the compost piles can be
removed and piped back into the
treatment plant. A four-foot
retaining wall has also been added
to one side to make it easier to
scoop up the composted material.
Aeration can be the most
difficult aspect of composting.
This can be accomplished by
windrowing (piling the sludge into
25
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long narrow rows), but given New
England's weather, it was decided
that forced aeration would be more
practical and efficient. Small fans
and pipes are used to move air
through the compost piles. Because
sludge is so wet and heavy, a
bulking agent is mixed with sludge
to aid air circulation. Wood chips
are used as the bulking agent in the
Durham project.
Several methods were used to mix
the compost and wood chips during
the pilot program. A front-end
loader, sometimes in combination
with a grader, was initially used at
Durham. The problem was that this
tied up equipment and labor for a
full day for each pile. The sludge
itself can also create problems; in
cold weather it tends to freeze, and
sludge waiting to be mixed tends to
smell after a week because without
aeration it becomes septic. The new
facility is now experimenting with
an indoor pugmill that mixes the
sludge and bulking components in the
proper ratio. The mix can then be
added to the compost pile each day
year round. The town anticipates
that labor requirements will be
substantially reduced. Also, the
problem of noxious odors should be
eliminated.
A typical Durham compost pile
handles about 60 cubic yards of wet
sludge and 180 cubic yards of wood
chips, and measures 60' x 15', and
is ten feet high. A layer of
composted material one foot thick
over the pile acts as an effective
insulator. Over the course of about
three weeks the temperature within
the pile will rise, peaking at about
73°C, and then fall off again. The
heat kills most harmful bacteria,
but benefits the bacteria that do
the actual composting.
Air is circulated through the
piles with a one-half horsepower
blower connected to perforated pipes
placed under the compost piles.
During the pilot project, the piles
were regularly monitored for both
heat and oxygen. Since the heat
produced by the bacteria composting
the sludge is dependent on the
oxygen level, only the temperature
of the piles needs checking to
assure the composting process is
working properly. It is important
that the piles attain the necessary
temperature to kill most of the
harmful bacteria in sludge.
Composting is completed in about
21 days. However, the compost isn't
fully stabilized until after another
30-60 days. The final step in the
composting process involves
screening of the mixture to separate
the wood chips from the compost
material. Since the compost remains
wet and in larger clumps in the
winter, a 3/4 inch mesh screen is
used to retrieve about 50% of the
wood chips in the compost process.
In warm or dry weather, a finer 1/4
inch mesh screen is used for up to
80% retrieval of wood chips. The
remaining wood chips not recovered
help stabilize the compost and add
to its value as a bedding material
for horticultural uses.
Because it is most convenient to
screen the compost right on the
composting pad, the town is building
storage bins directly adjacent to
the pad. A conveyer belt will be
installed to catch the wood chips
and carry them to a separate bin for
reprocessing. The composted
material will drop into bins and
remain curing in the bins from four
to six weeks. Table 1 shows
estimated operating costs to process
one pile of compost during the pilot
project.
26'
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TABLE 1: COSTS INCURRED, EACH PILE
(42 WET TONS or 10 DRY TONS) (1975)
ITEM
COST
ADS Flexible plastic pipe
56.00
Wood Chips ($3.25/cubic yd) 585.00
Mixing equipment and labor1 120.00
Monitoring of pile
Electric power
Capital Costs2
TOTAL
52.00
3.00
6.00
$822.00
Cost per dry ton of sludge
(42 wet tons per pile) $19.57
Cost per dry ton of sludge
(10 dry tons per pile) $82.20
(The capital costs of the compost
process were not included in the
cost per pile.)
1 Use of loader and personnel
(8 hours)
2 Capital expenditures spread over
the life of the project; does not
include construction of compost pad.
What can be done with the
composted material? This question
is still being debated. In Durham,
the compost is being used to fertil-
ize and condition soil along road-
ways and parks. Among Durham's
residents, the compost is so popular
for gardening that the town has to
hide supplies when they are needed
for a special project. Tests
indicate that there are virtually no
pathogens in the end product, and
the State's Department of Public
Health has given tentative approval
for application of composted sludge
as a soil conditioner.
Since Durham is a residential
town, the compost is free of the
heavy metals typically found in
sludge from industrial areas. The
compost is well suited for
ornamental gardens and lawns since
it creates good soil structure and
provides needed aeration and water
retention for plant growth.
University of New Hampshire
experiments indicate that it can be
used on a layer of plastic sheeting
to grow turf in half the usual
time. There is still a reluctance
on the part of many officials to
sanction the use of sludge compost
for food production. Fears of heavy
metal or pathogen contamination
still exist particularly if
industrial wastewater is treated
with the domestic sewage.
Although in some States
composted sludge is sold or given to
homeowners and farmers as a soil
conditioner and organic fertilizer,
the development of specific
regulations will be needed to define
acceptable standards for the use of
compost in both ornamental and food-
crop applications.
For more information contact:
George Crombie
Public Works Director
Town of Durham, NH 03824
27
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METHANE CONVERSION FOR FUEL
MODESTO, CA In Modesto, California,
a small fleet of cars
and trucks are fueled
with biogas produced at the city's
wastewater treatment plant.
The biogas is a by-product of a
bacterial process (anaerobic
digestion) that is used at the plant
to treat municipal sewage. The
biogas from the digester contains
methane gas, the essential ingredient
in natural gas. Unfortunately, the
gas also contains small amounts of
potentially corrosive carbon dioxide
and hydrogen sulfide. Engineers have
long known that the methane is an
energy source, but only recently have
efforts been made to harness and use
it.
"Initially," explained John
Amstutz, "We saw the big flare stack
here wasting close to 200,000 cubic
feet of gas a day and we thought the
vehicle idea would be pretty good.
Then along came the energy crunch."
As in many other situations, the
energy crisis became the impetus for
action.
The primary problem in using
biogas is separating the methane from
the other by-products. Diluted by
carbon dioxide, raw biogas does not
contain enough energy to run a
vehicle. The hydrogen sulfide and
carbon dioxide in the gas can produce
excessive wear on the engine.
However, once the biogas is cleaned,
it can be compressed and stored as an
efficient, clean burning vehicle
fuel. Central Plants, Inc., a
subsidiary of a major utility holding
corporation in southern California
(PLC), began working with the city of
Modesto to develop the technology
needed to harness biogas. The result
of this research is a new process
(Binax system) for processing small
to medium volumes of biogas (25,000 -
2,000,000 scf/day). The system uses
ordinary water under pressure to
remove the contaminants in the gas.
To process the gas from the
digester, it is first compressed and
injected into the base of a pressur-
ized tower. As the gas flows up the
tower, water flows down through a
series of trays and absorbs the con-
taminants. A second tower purifies
the water for recycling. The end
product, 98% pure methane, is
essentially the same fuel as natural
gas. It can be used for heating,
generating electricity, or running
machinery. But most important - it
can be used as an effective and low
cost fuel for vehicles. This is
demonstrated in the Modesto study in
which seven cars and trucks are
operated with this new, renewable
energy.
Few people realize that vehicles
can easily be adapted to accept
compressed natural gas yet still have
the option of running on gasoline.
The technology, developed by Dual
Fuel Systems, Inc., an affiliate of
Central Plants, Inc., is over a
decade old. It has been successfully
used in fleets throughout the world.
It is a popular system in New Zealand
where natural gas is plentiful and
oil is scarce. The modifications are
simple. They require little change
to the engine itself and the
equipment can easily be removed and
used on replacement vehicles. Five
basic parts are added to a standard
vehicle:
1. Refueling Connection: a small
refueling port located under
the hood;
2. Gas/Air Mixer: mounted on top
of the carburetor to replace
28
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the air cleaner, this blends
the methane and air for
optimum combustion;
3. Storage Cylinders: each
cylinder holds 350 cf of gas
at 2,400 psig, the equivalent
of about three and a half
gallons of gasoline. Typi-
cally, cars are equipped with
two cylinders, fitted into the
trunk. Trucks may carry from
two to eight cylinders
depending on daily fuel demand.
4. Pressure Regulator: to
control the pressure from the
cylinders for the gas/air
mixer;
5. Fuel Selector Control and Fuel
Gauge:mounted on the dash-
board, this allows the driver
to check the gas supply and,
if necessary, switch to
gasoline.
Conversion equipment generally
costs $800 - $1,850 per vehicle and
typically takes 10-20 hours to
install. The equipment can be
transferred to other vehicles as
replacement vehicles become necessary.
There are two methods for
refueling the vehicle cylinders.
They can be "Quick Filled" in two to
five minutes from a cluster of high
pressure storage tanks, (3600 psi) or
"Timed Filled" over night, in 10-14
hours directly from the compressor.
In both cases the methane is
compressed and the pressure and
refueling is automatically
controlled. Either method can be
carried out by a trained operator,
usually the driver. Dual Fuel
Systems, Inc. advises that both
methods cost about the same. The
quick fill method may require a
greater initial capital investment in
equipment, but the difference is
usually offset by the additional
costs to install underground piping
to the parking area where the
vehicles are time filled over night.
Modesto uses a combination of both.
When Motor Trend Magazine tested
this Dual Fuel System they found only
one notable disadvantage in perform-
ance: methane causes a slightly
lower acceleration and throttle
response. However, they also found
excellent starting, lower wear and
tear on the engine, fewer oil
changes, and longer plug and muffler
life. In other words, methane is
good for the car. Methane also burns
cleaner and produces far less air
pollution than gasoline.
So far the Modesto system
indicates that methane can be
produced from biogas at a cost
equivalent to 30tf-50tf per equivalent
gallon of gasoline depending on the
size of the system. Considering the
cost of gasoline today (and the
importance of preserving and
diversifying energy resources) the
advantages of this system are
obvious. The Binax system at Modesto
was a test unit capable of producing
a 25,000 cf/day or 10% of the
potential digestor gas available.
Plans are ready for a full-scale
system that processes 200,000
cf/day. This scaled up version will
produce the equivalent of 1,200
gallons of gasoline per day, enough
to fuel the city's entire fleet of
300 vehicles. This is economically
feasible since the fleet returns to a
centralized location each day.
The cost of a biogas scrubbing
and conversion system will vary
according to design requirements,
size of system, and installation
characteristics. In Modesto, the
pilot conversion project cost
29
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$300,000. In May 1982, after a
successful trial, the Modesto City
Council approved $1,000,000 to fund a
full-scale project. This will enable
the city to utilize the entire sewage
treatment plant biogas production.
Estimates indicate the entire system,
including conversions, should pay for
itself in less than three to six
years, depending on the method of
financing and the price of gasoline
they are foregoing.
Since the first biogas process-
ing system was installed in October
1978, the only time the system has
not been operational was in late 1980
when chemical toxins were accidently
discharged into the wastewater. This
killed the bacteria in the digester
tank. It took nearly a month to
fully reactivate the plant. During
that time the supply of biogas was
cut off. Modesto will tie into the
local gas company's pipelines to
provide a backup in the event of
future breakdowns in the digester
tank.
Wastewater treatment plants are
not the only source of biogas;
landfill sites, animal feedlots, food
processors and farms can also produce
it. Nor is the methane limited to
use by vehicles; a town could use
methane to run machinery, heat a
building, or produce electricity.
Modesto plans to use its excess gas
to fuel its boilers at city hall.
Any town with a population of
more than a few thousand, partic-
ularly those which already have
sewage treatment digesters, should
consider following Modesto's
example. As John Amstutz put it,
"Otherwise we're talking about the
equivalent of 1,000 to 2,000 gallons
of gasoline going up in flames every
day."
For more information contact:
R. Anthony Henrich
Central Plants, Inc.
6055 East Washington Blvd.
Suite 817
Commerce, CA 90040
John Amstutz
Water Quality Control
Superintendent
Public Works Department
P.O. Box 642
Modesto, CA 95353
James Bennett
Division of Water Quality
California State Water Resource
Control Board
P.O. Box 100
Sacramento, CA 95833
30
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NON-CONVENTIONAL SYSTEMS
-------
OVERLAND FLOW LAND APPLICATION
EASLEY, S.C. Easley, South Carolina
and neighboring Clemson
University have been
working together on a new approach to
wastewater treatment. Known as over-
land flow, this type of land treat-
ment system is in many ways so simple
that many ask "Is that all there is
to it?"
The basic concept is to distri-
bute wastewater through pipes across
the top of a hill, letting the waste-
water flow evenly over a sloping
grassy plot to the bottom. The only
pretreatment necessary is screening
out large solids and grinding up the
remaining solids so they do not block
the distribution system and are more
receptive to further breakdown. As
the sewage flows down the hill,
grass, soil and bacteria remove the
suspended solids, organic materials,
and most of the nutrients such as
nitrogen and phosphates. The water
is caught in ditches at the bottom of
the slope and disinfected if
necessary before it discharges into a
local stream. This remarkably simple
process produces effluent of better
quality than many secondary treatment
plants using sophisticated technology.
Experiments at Easley have been
carried out .both with raw wastewater
and wastewater that has been lagoon
treated. Interestingly, applying raw
sewage resulted in better treatment
than applying the partially treated
water from the lagoon. This is
because algae growing in the lagoon
water tend to survive the downhill
trip, remaining in the effluent as
suspended solids, causing a slight
discoloration. However, the
lagoon-treated effluent does tend to
be lower in phosphorus and nitrogen.
Dr. Abernathy, the program director,
suggests that it may be possible to
eliminate the lagoon in a completely
new overland flow system.
Mechanically, the system is
simple. Perforated pipes distribute
the wastewater at the top of the
hill. Experiments with a spray
application system did not work as
effectively because the sprayer
nozzles tended to clog. Blockages in
the half-open pipes can be cleared
easily. A fine glass-like matting of
solids accumulates at the top of the
hill, near the pipes, but this has
caused no problems during two years
of operation.
There are several important
design factors. Ideally the slope of
the land should be between 2 and 8
percent. If the slope is greater,
the water runs off too quickly and
can cause erosion, and less effective
treatment. If the slope is less than
2%, standing water may occur creating
an open invitation to mosquitos,
odors, and other nuisances. The land
must also be evenly graded to
maintain uniform flow. There must be
enough topsoil to allow plant growth,
but it should be impermeable enough
that the wastewater will flow over
the surface and not penetrate the
soil.
The kind of grass grown on the
slope is also an important consider-
ation. Perennial grasses with long
growing seasons, high moisture
tolerance, and extensive root systems
are best. In some projects this
grass has been harvested for cattle
feed. The Easley program is baling
the hay and using it offsite for a
number of purposes including animal
feed, erosion control, etc.
31
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A system of this kind can be very
inexpensive to build and operate, but
land costs will vary from site to
site. The slope of the land, type of
soil, and quality of the wastewater
will affect the amount of land that
is necessary. To give an idea of
land requirements, Easley's
experimental facility serves a
population of 800 to 900. There are
ten plots (more than actually needed)
of land 100' x 150' which handle
lagoon water; and three plots 110' x
165' that handle raw sewage. Easley
spent from $600 to $800 a year on
electricity to run the pumps and from
$500 to $600 a year to cut the
grass. Other operational expenses
are fairly low because there is no
need for highly skilled labor.
Dr. Abernathy warns that while
overland flow is an economically
sound, ecologically effective
approach for some locations, it has
quite a few limitations. The system
is best suited to small towns that
have land readily available at a low
cost. The soil should have a high
clay content to help prevent seepage
of untreated effluent that could
contaminate groundwater close to the
surface. The Easley facility has had
no trouble with odors.
Overland flow is also better
suited for mild climates. Cold
weather tends to slow the biological
activity that is part of the cleans-
ing process, and freezing weather can
lead to frozen equipment. If there
are long periods of freezing weather,
adequately sized lagoons are nec-
essary for winter effluent storage.
There is some irony in speaking
of overland flow as an experimental
system, for land treatment is as old
as civilization itself. The Easley
experiment was to determine how to
achieve consistent results. Several
studies are being carried out to
define specific optimum operational
requirements. It is encouraging to
note that the Campbell Soup Company
has been using an overland flow
system in Texas for twenty years and
is now treating between 5 and 7
million gallons of wastewater a day
using overland flow. They have
committed 900 acres of land to the
program, much of it reclaimed from
land which was previously heavily
eroded.
During a 1980 conference at
Clemson University, Paul Traina,
Water Division Director for EPA
Region IV, made some important
comments about overland flow:
"I've been the Water Division
Director for only six months --
prior to that I was the Regional
Enforcement Director. One of my
first briefings was from David
Ariail on the subject of land
treatment for municipal wastes.
I listened quietly, but when he
started talking about using raw
sewage on the land my old Public
Health/Sanitary Engineering
background erupted and I told
Dave that he and all others
involved in this hideous plot
were crazy! Well, Dave is a
patient fellow, and he kept
giving me literature and reports,
and yesterday he and Ray
Abernathy took me to see the
Easley site. Well, I've stood in
the middle of all kinds of sewage
treatment plants in my 20-plus
years in this business, and no
matter how well they were
designed and operated I always
knew where I was standing. Well,
yesterday I stood in the middle
of the Easley overland flow
system, and while I won't tell
you it was like standing in the
middle of a wheat field — it
32-
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sure wasn't like standing in the
middle of a sewage treatment
plant! The point of the comment
is that I have come into this
with a fairly closed mind, but it
is being opened."
For more information contact:
A Ray Abernathy
Environmental Systems Engineering
Clemson, SC 29631
I & A Coordinator
Water Division
U.S. EPA Region IV
345 Court!and Street NE
Atlanta, GA 30308
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SOLAR AQUACULTURE
HERCULES, CA Hercules is a "new
town." Built on open
industrial land, only
500 people lived here five years ago,
today the population is 6,500.
Hercules is expected to grow to
22,000 population by 1995. This
planned growth would have overwhelmed
even the newly expanded wastewater
treatment plant in the neighboring
city of Pinole. Pinole can handle
Hercules wastewater now — until the
innovative Hercules plant is proven
and certified by the State of
California after a two year trial
period. In order to carry out their
plans for development of the "new
town" and its rapid growth, Hercules
had to go it alone in order to
provide sanitary sewage facilities
without State and Federal financial
assistance. The experimental solar
aquaculture plant was affordable and
worth taking the risk of constructing
the first large scale application of
an innovative system.
Ralph Snyder, the city manager,
explained Hercules' choice:
"What we're simply doing is
buying a little bit of high
technology and confining it into
an area in a greenhouse environ-
ment, but doing essentially the
same thing as the sun and bugs,
water plants and fish have done
for thousands of years. In other
words, they have created an
environment, not unlike a marsh,
using some modern technology to
speed and control the process.
The system is called solar
aquaculture."
The basic structure is a series
of ponds enclosed in a greenhouse
made of double-layered plastic
sheeting. The greenhouse helps
maintain an average temperature of 70
degrees, year-round. The raw waste
is first screened, and then piped
into the primary anaerobic-treatment
pond where one third of the solids
are settled, digested, and converted
to methane gas. The pond is lined
and covered with a rubber membrane to
control odors. Following anaerobic
digestion, the wastewater flows to a
second heavily aerated pond that
contains activated bio-webbing, a
seaweed-like plastic film which
provides a high surface area for
growth of the aerobic bacteria and
protozoa that feed on sewage. In
fact, this bio-webbing is one of the
major innovations of the system and
substantially speeds the treatment
process.
The water then moves to a third
pond where it is again aerated. This
pond, in addition to containing bio-
webbing, is planted with water
hyacinths and duckweed. The pond
also plays host to small, waste-
consuming invertebrates which are, in
turn, eaten by small fish. The
hyacinths metabolize not only the
wastewater nuturients, but also toxic
compounds and heavy metals. In
addition, this thick floating plant
cover prevents the growth of unwanted
algae, a problem which often plagues
lagoon systems. Harvested water
hyacinths can be composted and used
as soil conditioner or digested to
produce methane gas.
At the end of the treatment cycle
the water passes through a sand
filter, which removes any stray
organic matter and finally is
disinfected with ozone.
The process takes about three
days to produce a secondary quality
effluent that can be used for crop or
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landscaping irrigation. With six
days of treatment the effluent is
suitable for industrial reuse, stream
enhancement, or groundwater
recharge. Since 25 percent of the
land in Hercules is being reserved
for greenspace, the city intends to
use some of the water for
landscaping. Local industries will
also be interested in using the
recycled water.
The Hercules plant is still
experimental. The first aquacell
covers 1.5 acres and handles 350,000
gallons per day. If successful, the
facility will eventually be expanded
to 6 acres and be capable of treating
2 million gallons per day. The
projected cost for a full scale
facility (about $3.5 million) is
approximately the same amount
necessary to expand the secondary
treatment plant in Pinole.
Construction of an independent
advanced treatment facility would
cost two or three times that amount.
Operation and maintenance costs
should be about one-third those of a
conventional plant. It is also
anticipated that the sale of the
recycled water will compensate for a
large amount of the operation
expense. User costs are currently
$70 per year with water recycling.
One of the more interesting
aspects of the Hercules plant is that
almost everything going into the
system can be transformed into a
valuable by-product. Hercules
intends to use the harvested water
hyacinths, mixed with sludge, as a
compost for landscaping. The
hyacinths could also be used as
animal feed or converted to methane
gas and then to electricity. In
Mississippi, another experimental
program funded by NASA uses water
hyacinths to remove precious metals
from industrial wastewater. In other
parts of the world, countries with
food shortages employ
aquaculture,using wastewater, to
produce food for humans and animals.
The efficiency of this system has
drawn a great deal of attention from
all over the world, particularly from
countries with shortages in water
and/or land. International visitors
to the Hercules experimental plant
are also interested in the potential
for food and energy production. This
system recognizes how precious our
natural resources are. Even in an
urban area, it is possible to wed the
disciplines of biology and
engineering to transform wastewater
treatment into a means of preserving
our precious natural resources.
Postscript:
March 1982.
After 2 years of innovative
operation, the Hercules Town Council
voted to shut their experimental
plant down permanently. The Council
evaluated and rejected the costs
required to correct operational
problems necessary before State
certification could be given.
While the experiment was
generally successful, it was plagued
by some operating problems that were
expensive to correct.
Much can be learned from the
Hercules experience with full scale
solar aquaculture: day to day
operation at full-scale has indicated
that the optimum pond depth is 1' to
3'; maintenance of moderate summer
temperatures is vital to healthy
aquatic plants; comminution of
influent is necessary; clean-out of
the anaerobic unit is necessary; the
integrity of the impervious pond
lining material must be respected;
and the source of power for inflating
a greenhouse cover, operating pumps,
and aerators must include an
emergency backup.
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Meanwhile, the City of San Diego
is presently designing a pilot
aquaculture system that will treat up
to 1 mgd of wastewater.
For further information contact:
Chris Alsten
Director of Special Projects
Solar Aqua Systems, Inc.
P.O. Box 88
Encinitas, California 92024
Ralph W. Snyder, City Manager
City of Hercules
555 Railroad Avenue
P.O. Box 156
Hercules, California 94547
James Bennett
Division of Water Quality
California State Water Resources
Control Board
P.O. Box 100
Sacramento, California 95833
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PLANS FOR COMPLETE RECYCLING
SAN DIEGO, CA San Diego's
water resource
problems are, in
most ways, quite similar to those
of St. Petersburg, Florida. In San
Diego the little fresh groundwater
that originally existed was
consumed long ago, leaving nothing
but brine in the aquifer. There-
fore as the city grew, nine dams
and reservoirs were built to
contain rainwater, but the rainfall
could only supply a population of
about 50,000. Already at 2
million, the San Diego area's
population is expected to reach 4
or 5 million by the turn of the
century. For decades the city has
been buying water and transporting
it from the Colorado River hundreds
of miles away. But that supply is
no longer dependable for future
needs. Richard King, San Diego
Water Utilities Director explains:
"There are four thousand
billion gallons of water that
fall on the United States
today, of which 1200 billion
end up in the drinking water
supply throughout the country.
In 1975 we were using one-third
of that supply. Now, if our
future is a straight line
projection, then within the
foreseeable future, by the turn
of the century, finding an
adequate water supply for any
place in the United States is
going to be a major problem."
San Diego is somewhat unusual
because both fresh water and sewage
services are managed by one
authority, the Water Utilities
Department (WUD). It naturally
follows then that water supply and
wastewater treatment are considered
together. Conservation of the
severely limited supply was a
natural first step and began with
an attempt to reuse secondary
effluent water for industrial and
irrigation applications.
Unfortunately San Diego's industry
only accounts for 5% of water
demand (50% is common in more
industrial cities), and most of
that is for food processing which
requires potable water. Irrigation
of golf courses and cattle range
proved unsuccessful because the
treated effluent's high salt
content killed the grass. This
problem coincided with the
development and testing of a new
technology, reverse osmosis, to
remove salts, but this process is
energy intensive, resulting in yet
another problem.
To answer the question "How are
we going to serve the water and
sewer needs of the city of San
Diego over the coming years?", a
panel of experts was asked to
consider the question in full
perspective.
Breaking with convention, this
panel came up with an innovative
answer, "There's only one place for
your sewage, and that's back in the
drinking water." WUD realized that
fully recycling their water supply
would require strict controls and
possibly new technologies to assure
the prevention of disease. Many
regulatory changes would also be
necessary. The panel based its
recommendation on the belief that
it was wasteful to invest in
treating wastewater only to dump it
into the ocean, especially when
recycling was a technically
feasible alternative.
The first treatment concept
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they explored was a bio-lake.
Effluent would flow into an
artificial lake which was oxygen
enriched and stocked with flora and
fauna that digest organic wastes.
The study team was then directed to
NASA's research on the use of water
hyacinths for sewage treatment.
"Water hyacinths," (and a
number of other aquatic plants) "as
it turns out, have an affinity for
heavy metals and things normally
called toxic substances," Mr. King
explained. Interestingly enough,
water hyacinths also do a good job
of removing DDT and pesticides.
The hyacinths can also remove some
of the salts in the wastewater
which make the reclaimed water
unsuitable for irrigation.
Without realizing it at first,
San Diego was moving toward an
aquaculture solution. In their
proposed system the hyacinth crop
will be harvested and processed in
a digester (as in Modesto, CA) to
produce methane to fuel the
wastewater treatment system. The
effluent will then be filtered
through sand and the portion of
water destined for farm irrigation
drawn out of the system. The
portion destined to the city's
water supply will undergo further
treatment by reverse osmosis to
remove minerals; pass through a
carbon adsorber to remove the last
traces of organic matter; and be
exposed, once again, to ozone for
disinfection. The end product will
be potable water.
An aqua-cell system large
enough to handle San Diego's needs
will require hundreds of acres of
land. Since the water produced may
exceed demand, planning for an
agricultural facility will be
included so that any excess water
will not go to waste. Finally,
since San Diego's sister city,
Tiajuana, faces similar water
shortage problems, the two cities
are considering sharing the re-
cycling facility. They may build
it in a valley which lies between
both cities.
Complete recycling for the San
Diego area is a grandiose plan. It
will cost hundreds of millions of
dollars to realize. Yet, in the
long run, it should be cost
effective for a city like San
Diego. Conventional treatment is
expensive and it yields little or
no usable end-products. It may
require progressively more advanced
and more expensive treatment in
many locales to meet water quality
discharge standards. These
advanced technologies are energy
intensive and require far more
energy to operate than aqua-cell
systems. Mr. King explains that,
for the San Diego water utility
district, the bottom line is not
capital costs but the monthly
charge to homeowners for operation
and maintenance of water and sewage
services. San Diego's
"system-for-tomorrow" will provide
water and sewer services at
one-third the operating cost of
conventional technologies and
guarantee a continous supply of
potable water for the future.
San Diego has already committed
3.5 million of local, state, and
federal dollars to a pilot
project. They recognize that
convincing the public and solving
all the technical problems may be
difficult, but they are willing>to
take this bold step because it
seems to be the least costly, best
solution for San Diego.
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For more information:
Richard W. King
Water Utilities Director
City Administration Building
202 C Street
San Diego, CA 92101
I & A Coordinator
Water Division
U.S. EPA Region IX
215 Fremont Street
San Francisco, CA 94105
James Bennett
Division of Water Quality
California State Water Resource
Control Board
P.O. Box 100
Sacramento, CA 95833
39
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NON-STRUCTURAL APPROACHES FOR
WASTEWATER MANAGEMENT
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COMPREHENSIVE PLANNING FOR ENTIRE WATER SYSTEM
MONTEREY, CA California's
severe drought
in 1976-77
shocked residents and officials
into planning for the future water
needs of the Monterey Peninsula.
It was the fourth severe dry period
in less than a century -- future
droughts were bound to occur. Just
two consecutive years of less-than-
average rainfall would strain the
region's reservoirs and limited
groundwater reserves. The crisis
brought the region's water re-
sources into focus. Clearly,
responsibility for those resources
could not remain fragmented among
various agencies.
The Monterey Peninsula is not
unique in terms of its water
problems. However, it has taken a
unique approach to solving them and
avoiding more serious problems in
the future. Until recently the
management of their water resources
was fragmented among many agencies
with overlapping jurisdictions at
different levels of government.
This fragmentation made it dif-
ficult at best to coordinate
management, policies, construction,
etc. It reached a point where
three different dam/reservoir
proposals for more water supply
were under consideration while at
the same time other agencies
responsible for treating wastewater
were discharging it into the ocean,
essentially lost for re-use. The
fragmented system was fostering
inefficient use of the resource.
Monterey was in a good position
to eliminate these problems of
fragmentation because its watershed
is entirely confined within the
borders of the towns that make up
the peninsula. Many communities
have to deal with several
jurisdictions because they are
importing or exporting their water
outside their borders, but happily
this is not so in Monterey. In an
effort to develop a systematic and
coordinated approach to managing
their water, the Monterey Peninsula
towns created a single water man-
agement district which was given
the powers previously held by many
separate agencies.
In 1977, the Monterey Water
Management District was formed,
according to the legislation,
because:
"...there is a need for
conserving and augmenting the
supplies of water by integrated
management of ground and
surface water supplies, for
control and conservation of
storm and wastewater, and for
promotion of the reuse and
reclamation of water. In this
region of primarily scenic,
cultural, and recreational
resources, which are partic-
ularly sensitive to the threat
of environmental degradation,
such need cannot be effectively
met on a piecemeal basis."
The key word in this legis-
lation is integrated. The primary
responsibility of the District is
to assess and plan for the present
and future water needs of the
Monterey Peninsula. The District
has been given a wide range of
responsibilities and the power to
administer them. They are pursuing
many projects and programs, some of
which are described below.
However, the District's major
strength is planning
comprehensively for the community's
entire water system, not just a
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part of it. Each project is
assessed in relation to the whole
and in relation to the other
projects.
The District can levy taxes,
establish charges for water,
declare rationing, and contract for
construction or research. District
responsibilities such as preventing
pollution of streams and urban
reclamation are more commonly
divided among several different
agencies. In Monterey's case,
everything from stocking water
reserves to sewage treatment, from
flood control to recreational
facilities, is now, by law, under
the auspices of one agency.
The District's first goal was
to determine current water usage
rates. To accomplish this, all
water producing facilities, such as
wells, are required to register
with the District and report their
usage rates. Through a permit
process, the District can manage
and control the existing and future
demand for water. The District
established the maximum number of
connections possible in each water
system, based on the available
resources.
The District has also allocated
the total supply among existing
land use agencies. This gives each
jurisdiction an incentive to
conserve its resources and plan for
new development without exceeding
the available water supply. This
procedure helps track growth in new
demand for water.
The District has the advantage
now of complete overview of the
whole water management system.
From that vantage point the
district has the ability to
evaluate modifications to the
system and their net effects on the
whole system, not just a small
portion of it. For example, from
the wastewater manager's viewpoint,
an ocean outfall is an inexpensive
means to dispose of effluent.
However, the water lost via ocean
outfall might be very expensive
water to replace by constructing
more supply (reservoirs, dams,
etc.).
The systematic approach allows
for a more thorough financial
analysis of investment options for
best overall system performance. A
complementary investment mix
including supply augmentation,
wastewater treatment, supply
protection, and end use efficiency
can be orchestrated to produce an
overall least-cost system to the
community.
The district is not limited to
structural approaches to water
management. Controlling use of
non-potable water in public
facilities and in new construction
is currently under study. For
example, schools and other public
buildings may be built or
retrofitted with rainwater
collection systems. The water from
roofs or parking lots can be used
for irrigation of playgrounds and
open spaces. In new construction,
developers may be required to meet
50% of the anticipated demand for
water through resources other than
groundwater supplies. Cisterns
and/or other water recovery systems
will be used. To encourage this
effort, the District is reviewing
the available technologies for
reducing water demand in new
construction.
A State funded reclamation
study to demonstrate the use of
treated wastewater (secondary
effluent) to irrigate leafy
vegetable crops is now underway.
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This kind of water reclamation
offers potential economic, water
quality and water quantity benefits
to the entire State.
Monterey instituted several
programs to protect existing
supplies. Preliminary tests
indicated pollution of groundwaters
from failing septic systems. So,
the district is now drilling a
network of water quality monitoring
wells which will help spot these or
other sources of pollutants
entering the groundwaters. When
severe erosion occurred on the
banks of the Carmel River (their
primary local water source), the
District began a program to co-
ordinate the mangement of this
essential watershed. It will play
a major role in bank stabilization
and channel clearing.
The District promotes con-
servation of existing water
supplies. For example, landscape
gardeners are being encouraged to
select plant vegetation requiring
little water. This reduces the
amount of water used for landscape
irrigation.
The combination of regulations,
conservation programs, and
protection of the watershed
represents the most feasible,
cost-effective solution for
extending supply. In turn, these
programs help to indicate what
additional reserve capacity is
required to meet the anticipated
future demand for water.
One of the projects being
considered is tapping and re-
charging the District's groundwater
aquifers (water bearing rock
formations). A computer model has
been developed to analyze the
implications and potential of such
a program.
Plans for a new dam and
off-stream reservoirs are also
being studied. Such a large
project does require approval by
popular vote and by the state
government. Impacted by the famous
Proposition 13 of 1978, efforts of
this magnitude are certainly beyond
the scope of any private water
supplier. Even more significant,
the District's new ability to view
the water system as a whole will
assure taxpayers that such major
investments yield optimum
benefits. Several sites and
capacities are under consider-
ation. The District's decision
will be based on how the new
facilities can best interact with
the rest of the water supply system.
For more information contact:
Bruce Buel
General Manager
Monterey Peninsula Water
Management District
P.O. Box 85
Monterey, CA 93940
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WATERSHED ORDINANCE
CRESTED Water is a limited
BUTTE, CO resource. Until
recently, the
abundant water supply in the United
States has been ample to meet our
needs, but increasing population
demands, water-intensive
activities, and pollution, have
rapidly been depleting and
degrading that supply.
The inappropriate use of water
resources creates costs which the
taxpayer must ultimately bear. For
these reasons, a small town in
Colorado has resolved to protect
its water supply for all potential
users.
Crested Butte is located in the
Rocky Mountains near the Gunnison
National Forest. Recently, a
mining company expressed interest
in a mining venture within the
watershed that supplies the town's
drinking water. Crested Butte
understands that if the mining
venture changes the quality of the
water available in the watershed it
also affects the quantity available
for potential users. Therefore,
the town has passed a watershed
ordinance which attempts to protect
the watershed for all users. Thus,
if the mining company can conduct
their activities without destroying
other's ability to use the water,
then the mining company may use the
watershed.
The Watershed Ordinance shifts
the burden of proof to the mining
company or the timber harvester or
the developer to assess the worst-
case situation; the cumulative
impacts of these activities; and,
in a potential high-risk situation,
to post a reclamation bond which
would insure the clean-up or
replacement of water supply in the
event of major pollution. Crested
Butte defines pollution as any
alteration of the physical,
chemical, biological or
radiological quality of their water
that is or may become injurious to
the public health, safety and
welfare. This includes activities
which are injurious to domestic,
commercial, industrial,
agricultural or recreational uses
of water. Activities which are
injurious to the utility of
riparian lands, livestock,
wildlife, the value of fish or game
are also considered pollution.
This includes activities which
produce water which is offensive to
sight, taste or smell.
The town requires a permit for
any activities which affect the
town's waterworks. The town
defines its waterworks as any and
all human-made components and any
and all natural components of the
airshed/watershed surface and
groundwater basin included in the
operation and design of the town's
water supply system. These
components include, but are not
limited to, all storage facilities
such as water tanks, reservoirs,
stream courses and groundwater
basins; all transmitting facilities
such as pipes, drains, pumps,
stream channels, hillside slopes
and bedrock; and all filtration
facilities including plant life and
soils necessary for the
construction, operation and
maintenance of the town's water
system.
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Types of activities for which
the town would require a permit
include:
a) cloud seeding or other
aerial activities, such as
herbicide or pesticide spraying;
b) operating or constructing a
sewage or industrial waste disposal
system;
c) removing vegetation, such as
timber harvesting;
d) excavating, grading, filling
or subsurfacing, as encountered in
drilling operations or mining;
e) altering surface or
subsurface drainage courses;
f) diverting water in any
consumptive manner that increases
concentration of pathogens or toxic
substances in the water supply;
g) handling, using, storing or
transmitting toxic or hazardous
substances including, but not
limited to, radioactive materials;
h) using, handling or
transmitting flammable or explosive
materials except for domestic
purposes or within vehicular fuel
storage tanks.
Thus, Crested Butte's Watershed
Ordinance attempts to coordinate
and plan for all activities that
may affect water users' access to a
limited water supply. The
ordinance provides controls for all
activities that affect the town's
watershed. By preserving their
water quality, Crested Butte is
insuring a continuing supply to all
potential users, not only today but
in the future.
For more information contact:
Mr. Ron Landeck
Town Attorney
Town of Crested Butte
P.O. Box 39
Crested Butte, CO 81224
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WATER CONSERVATION STRATEGIES
VARIOUS Conservation,the least
COMMUNITIES expensive and
frequently the most
viable solution for many com-
munities' water problems is often
overlooked. When water supply is
temporarily short, particularly in
crisis situations, conservation is
viewed as a stop-gap measure.
Interestingly, many towns find that
these steps, when instituted as an
emergency measure, continue to be
effective on a long-term basis.
During a 1977 drought in Marin
County, California a conservation
campaign reduced water consumption
by 60%. After the drought was
over, the consumption rate remained
.30% lower than it had been in
1976. Unfortunately, communities
often fail to realize that
conservation can also reduce the
wastewater stream and, therefore,
reduce the demand on existing
sewage treatment systems.
Recently, Elmhurst, Illinois
faced water shortages. While the
town is only 20 miles from Lake
Michigan, the competition between
Chicago and its suburbs for the
lake's water meant that Elmhurst
had to look elsewhere for
additional water supply. Their
choices were to spend $400,000 for
a new deep well or to use their
existing supply more carefully.
Elmhurst chose to launch a
door-to-door campaign teaching
residents about their water
system. Emphasis was on how to
repair household plumbing and other
ways to conserve water at home.
The campaign distributed two
devices: shower head flow
restrictors, and toilet dams which
help reduce water use. The cost
for the entire program was $50,000
or about $1.00 per household. The
resulting 13% reduction in water
demand not only eliminated the need
to dig a well, but effectively
"expanded" the capacity of their
wastewater treatment facility.
Elmhurst can now allow additional
housing units to be built in their
community without investing
additional funds in treatment
facilities.
In another town, Tisbury,
Massachusetts, residents were using
more water than their septic tanks
could handle. The over-flow and
septage from some malfunctioning
tanks were deposited in the town
dump — just 500 feet away from the
town well. There was an obvious
danger of contaminating the fresh
water supply so Tisbury began to
hunt for a treatment solution.
Engineers first suggested a
$12 million sewer and treatment
plant. The town voted against such
an expensive proposal. Then the
engineers recommended a watered
down $8 million version to serve
700 homes and businesses. This,
too, was rejected as were the
recommendations of another group of
engineers who suggested a
$2 million treatment plant for 120
homes.
In evaluating these proposals,
the board of health realized that
there had never been a study to
pin-point the problem. Members of
the community performed the study
and found a rather simple,
inexpensive solution. They
identified a few failed septic
tanks which needed to be repaired
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or replaced. Homes and commercial
establishments using more water
than their septic systems could
handle purchased low-flow devices
and toilets which used only two
quarts instead of five gallons per
flush. This seems to have greatly
improved the functioning of the
septic systems.
Low-flow shower heads and
toilet dams are only two of many
devices on the market which aid in
reducing water use with little or
no extra effort by the user. Below
is a list of these devices, how
they work, how much they save, and
how much they cost.
Flow Control Devices: Valves
which restrict the flow of showers
and faucets to 2.5 gallons per
minute. Water Savings: 50-60%.
Cost: $.50-55.00.
Flow Reducing Showerheads:
These replace regular showerheads.
Water Savings: up to 75%.
Cost: about $10.00-$!5.00.
Thermostatic and Pressure
Balancing Mixing Valves: These mix
hot and cold water to preset
temperatures eliminating the need
to waste water while adjusting the
temperature. Savings: Varies
according to family size and
ambient water temperature. Cost:
$75.00-$!25.00.
Toilet Dams: These are
flexible plastic panels that are
inserted into toilet tanks to hold
back a reservoir of water when the
toilet is flushed. You can also
weight a plastic bottle and put it
in the tank for a similar result.
Savings: 1 to 2 qts. per flush for
bottles; 1 to 2 gallons per flush
for dams. Cost: up to $8.00.
Shallow-Trap Toilets: These
fixtures have a smaller reservoir
than conventional toilets.
Water Savings: 1 1/2 to 4 1/2
gallons per flush.
Cost: about $80.00.
Pressure Toilets: a variety of
toilets are available in which air
pressure rather than a large volume
of water provides the velocity
needed to clean the bowl.
Savings: 2 1/2 to 7 1/2 gallons
$60.00 to
ings:
TTusI
per flush.
$600.00.
Cost:
Dry Composting Toilets: These
collect waste in an impervious con-
tainer and compost them into a soil
conditioner. The toilet uses no
water, creates no odor, and is
approved for use in 30 states.
However operation and maintenance
of composting toilets are sensitive
to temperature control and liquid
volume. Savings: 5 to 8 gallons
per flush. Cost: $1,000 to $2,000.
There are other devices
available and other means for
communities to conserve. A leak
detection and repair program for
both the public water supply system
and home plumbing can effect
significant water savings
especially in older towns. Changes
in plumbing, building, and health
codes can encourage water savings
in new construction.
Greywater (water that does not
contain feces or urine) can be
reused for irrigating gardens,
washing cars, and flushing
toilets. This approach can also be
applied in industry. For example,
an IBM complex built in Tucson, AZ.
was designed to capture rainfall
from roofs and parking lots and
recycle it for irrigation and other
uses.
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Water pricing can also impact
usage rates. During a drought,
Marin County, CA, alloted 40
gallons of water to each person,
per day. A penalty rate structure
increased cost of water used over
the basic 40 gallons a day from 6tf
per 100 cubic feet to $1.22.
Wastewater flow reductions of
between 25% and 60% were reported.
This was an emergency measure but
other utilities are now instituting
similar (but less severe)
increasing block rate structures.
In the long run it is people
and the way they use water that
have the greatest impact on water
supply. The way an individual
washes dishes or clothing, makes
landscaping decisions, bathes, and
considers water as a valuable
resource, will reduce the amount of
water wasted.
An aggressive community water
conservation program can reduce
failing septic problems; forestall
the cost of developing a new source
of water supply; and improve the
quality of wastewater treatment by
reducing wastewater volume; all for
a relatively low cost.
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