Opportunities for Decentralized
Center for Ecological
Pollution Prevention (CEPP)
P.O. Box 1330, Concord, MA 01742 USA
50 Beharrell Street, Concord, MA 01742
every island nation has identified critical environmental and public health problems
resulting from the disposal of human (and animal) excrement:
contaminated drinking water wells (nitrates, bacteria)
outbreaks of gastrointestinal disease, leptospirosis and cholera,
dying reefs, algae blooms and eutrophication in lagoons
causes of this pollution include:
overflowing latrines and privies
some sewage treatment plants
complete lack of sanitation facilities in some places
next to pour-flush latrine outside of Suva, Fiji
easiest way to divert potential
from the environment is
to use them up.
systems utilize the nutrients in water for productive reuse.
Create aerobic conditions:
bacteria--oxygen-using bacteria--can work 10 times faster than anaerobic bacteria
to destroy pathogens and convert nutrients to a plant-available form.
Use plants to eat, drink and evapotranspire the effluent.
both take up nutrients, evapotranspire moisture and provide root zones for biological
Conserve: Use water-efficient appliances and fixtures, so that less wastewater
is created. Examples: dry or microflush toilets and low-flow faucets and showerheads.
Pretreat: Filter at the source to remove larger particles so it can be
used by plants. In kitchens, use grease and food interceptors. Disinfect with
ozone or UV if to be used for potable water.
wastewater components: By
keeping flows separate, they can be better and more cost-effectively treated and
or reclaim effluents for use
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Resort, Beqa Island, Fiji
Upmarket resort with seven guest houses attracts divers and surfers. Owners wanted
non-polluting zero-waste discharge wastewater system that the
staff could easily maintain.
buildings, including the kitchen, at Lalati Resort (Fiji) are served by
Aerobic blackwater biofilter/Composting toilet (made of locally purchased plastic
container, with fittings; cost: $50USD)
Microflush toilets (1/2-litre flush/1 pint flush)
Wastewater Gardens that uses up all washwater (sinks, showers) and leachate from
Rooftop rainwater collection (to 2400-litre cistern) provides much of the resort's
staff adds coconut coir every few days. When a composting reactor fills--anywhere
from 3 months to 1 year--it is taken to a covered central area to further process.
In six months, the material should be fully processed and ready to be added to
a composting pile to further process or to be applied to soil.
It is less costly to prevent pollution than to treat it later.
bacterial and chemical pollution (health risks)
nutrient pollution (unwanted water weeds, dying aquatic life and groundwater contamination)
water (less water used, less water needs to be cleaned)
and reuses nutrients and water (saves money, no discharge)
save money over the cost of conventional systems
results: cost savings, natural resources preserved, disease transmission avoided,
nutrient and water cycle preserved on site
On-Site Graywater and Blackwater Recycling
Composting Toilet System
(a.k.a. CEPP Twin-Bin Net System)
Kosrae and Pohnpei, Micronesia)
Early 1990s, three different composting toilet systems were designed and demonstrated
through local construction workshops on the islands of Yap, Kosrae, Pohnpei, and
Palau. (Sponsor: Greenpeace; contractor: Sustainable Strategies)
When one chamber fills up, it is capped and the other side is made active.
When this one has filled, the other side can be emptied. At this point, what is
removed is a stable soil-like humus, which can be used as a soil conditioner.
It is usually five years before the first chamber is emptied.
most succesful installations were in Pohnpei, whereby several were built by the
property owners with plans and a small subsidy provided by a local agency.
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and Blackwater Recycling: Success Factors
success of introducing composting toilets (and other alternative wastewater systems)
Education: technical support and operator education
Design: some are better than others
Cultural factors: perceptions about system height, exreta handling, etc.
Cost: affordability (costs range from USD$60 to $3,000)
Awareness: perceived need for better sanitation
systems have been built and demonstrated in Fiji and Tonga)
Composting Toilet Systems
systems offer ready-made hardware and uniformity, although they can be expensive
to import and still require considered installation and user education.
Rock Islands, Palau (15)
Yap Institute of Natural Sciences (YINS)
W. Samoa and Tokelau Atoll
(1. Manono island, Samoa
2. Opening of system at YINS)
optimize these systems further, CEPP has:
optimized biological processing (faster!)
lowered the cost
urine-diverting toilet composting system in Mexico)
the United States, Europe, Australia and Asia, urine is diverted to prevent eutrophication
and nitrate pollution and to recover nutrients.
urine is usually sterile
urine contains 90% of the nitrogen in wastewater
can be done with urine-diverting toilets. The urine is
combined with graywater and used to fertigate crops
composted with high-carbon materials (wood chips, sawdust, cardboard, etc.)
(urine-diverting toilet from Sweden)
and Shallow Aerobic Leachfield Systems
aerobic planted (root zone) systems are increasingly installed as they provide
faster aerobic processing of effluent.
Constructed Wetlands: Saturated systems that provide aerobic transformation.
Wastewater and Washwater Gardens: are like wetlands but unsaturated, allowing
for more aerobic activity, faster processing.
Shallow, planted, aerobic leachfields: provide more aerobic treatment than
standard ones. The challenge is to prevent them saturation with rain
systems can be scaled up to serve clusters of homes and even whole communities.
more communities are moving toward managed decentralized solutions, as they can
be less expensive and more effective.
goal is to provide centralized management of decentralized systems. For many
areas, it is more cost-effective to fund and train a team of people to manage
many onsite systems than it is to construct, operate and train personnel for a
to manage decentralized systems, include municipal utilities, water boards,
and management contracts.
supply and wastewater are linked, as enhancing piped water supply historically
has the concurrent issue of more wastewater to manage. Also, wastewater choices
affect water quality.
(Village) and Central Systems
Sludge can be dewatered and composted or land applied (where appropriate)
where nutrients can be used by plants, such as timber crops.
Resulting effluent can be tertiary treated with wetlands and other aerobic
root zones systems
Or it can be land applied for use by timber crops and other crops (coconut
Aquatics: This is tank-based system, which serves a community of 300 homes,
acts as a super-optimized artificial wetland. Water is reclaimed for flushing
Hyacinth Large Central System: This water hyacinth system is a polishing pond
at a large wastewater treatment plant in California. Water hyacinth (a high-protein
pig food) takes up the nutrients and further treats the effluent before it is
discharged to the ocean. Eutrophication possibilities are thus reduced.
for Commercial Organic Effluents:
Boys Town: Biogas
fish or duckweed; best if product is not for human consumption, unless it is tested
is looking for a site at which to establish a demonstration of two systems
and educate a local resource person or agency.
for Ecological Pollution Prevention (CEPP)
P.O. Box 1330, Concord, MA 01742
The CEPP EcoSan Center promotes
ecological sanitation (EcoSan) systems, practices
and programs--we link people,
programs, information, and resources.