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Wastewater Management for the Islands:
Creating Gardens, Not Polluted Water

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Presentation, Fiji Ecotourism Association conference

December 2000 Nadi, Fiji

Carol Steinfeld
Center for Ecological Pollution Prevention (CEPP)
P.O. Box 1330, Concord, MA 01742 USA
Email: info@ecowaters.org Web: www.cepp.cc

David Del Porto
Sustainable Strategies
Ecological Engineering & Design
50 Beharrell Street, Concord, MA 01742 USA
Email: Info@ecological-engineering.com
Web: www.ecological-engineering.com

[text corresponds to slide presentation]

 

What's at Stake: Chuuk Polluted Beach
On a beach at a hotel on Chuuk (Micronesia), a sign warns visitors not to enter the water due to pollution. The pollution is from the hotel's sewage.

This situation is a reminder of what's at stake when waste is not well managed: not only is human and environmental health compromised, but tourist attractions can also be spoiled.

The answer is to use systems that divert potential pollutants from the environment. The easiest way to do that is to use them up.

The following are some examples of ecological systems, with an emphasis on strategic utilization and the simpler on-site aerobic systems (because our organizations have a history with these systems in the Western and South Pacific islands).

Lalati Resort, Beqa Island, Fiji
On Beqa island, Lalati is an upmarket resort ($250 per person per night) with seven bures (guest houses) mostly attracting divers and surfers. Its American owners wanted a wastewater system that would not pollute the nearby coastline with septage. At the same time, septic pumpout was not an option, due to their island location. Importing manufactured systems from Canada, Europe, the United States and Australia was going to be expensive.

They had seen a community composting toilet that Sustainable Strategies had built with the Fiji School of Medicine outside of Suva. Based on this, they asked the firm to design a system for an upscale resort with low-cost, locally available materials and with flush toilets--one that could be maintained by the resort staff.

The result was this system:

  • Each bure features a rooftop rainwater collection system, which drains to a 2400-liter cistern that supplies most of the bure's water.

  • Each bure features a microflush toilet (1 pint/1/2-liter per flush) flushed with rainwater and draining to an aerobic reactor (composting reactor), which was made on site with materials available in Fiji. Leachate (liquid) drains to a lined aerobic planter bed called a Wastewater Garden. All washwater (graywater) from the sinks and showers also drains to the Wastewater Garden, which is planted with local flowering thirsty plants. The aerobic reactors are changed out every few months, and their contents, after further processing, is used safely on the landscape. The kitchen is served by a similar system.

The staff of Lalati adds coconut coir every few days. When a composting reactor fills (with this small size, this takes 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. (Although this resulting humus should be pathogen free, we do not advocate its use on edible crops.)

Lalati's owners like the fact that the system does not pollute the coastline (and the very sites that attract clients) and that it is maintained by the resort staff. They also enjoyed significant cost savings over a septic system.

Guests, they say, appreciate knowing that their accommodations employ such an ecologically responsible system.

This system illustrates the good economics of the ecological approach.

The Ecological Approach
It is less costly to prevent pollution than to treat it later.

Advantages:

  • Prevents bacterial and chemical pollution (health risks)
  • Prevents nutrient pollution (unwanted water weeds, dying aquatic life and groundwater contamination)
  • Conserves water (less water used, less water needs to be cleaned)
  • Captures and reuses nutrients and water (saves money, no discharge)
  • Can save money over the cost of conventional systems
  • The results: cost savings, natural resources preserved, disease transmission avoided, nutrient and water cycle preserved on site

How: Conserve, Pretreat, Divert/Separate, Reuse/Reclaim
* Conserve Use water-efficient appliances and fixtures, so that less wastewater is created. Examples: dry or microflush or vacuum-flush 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.

* Divert/Separate wastewater components By keeping flows separate, they can be better and more cost-effectively treated and utilized.

* Reuse or reclaim
1. Plants use it up: Use the water and nutrients from wastewater to grow valuable plants--either for decoration or for fiber value. Choose plants that are especially hungry and thirsty to use up wastewater.

2. Reclaim it for other use: Flushing toilets and urinals, washing, etc.

 

El Santuario, Baja California Sur, Mexico
El Santuario is a lower-impact guest facility in south-central Baja California Sur, Mexico. Water is trucked in to the site from a mountain well.

Its owners needed a water-conserving system that would be acceptable to their guests. CEPP, using designs from Sustainable Strategies, designed small aerobic blackwater biofilter (enhanced composting toilets) with attractive blue urine-diverting toilets made in Mexico. A larger system was built for an adjacent area used for camping by kayak groups.

A Wastewater Garden was built for the kitchen, and a system that combines urine from the urine-diverting toilets and washwater from showers and sinks drains to a lined planter bed, which grows hibiscus and other tropical plants that serve as a privacy barrier. The initial construction took place as part of a three-day ecological wastewater workshop attended by builders and Harvard School of Public Health graduate students.

Rock Islands, Palau (Micronesia)
The Rock Islands are several small islands off of the coast of Palau that are popular stopping spots for divers and groups of snorkelers. High fecal coliform rates were measured around the islands, and ultimately traced to the latrines. It was feared that this pollution could kill off the sea life close to shore through eutrophication (and make visitors ill!). Sponsored by the Palau government and the United States Environmental Protection Agency, Sustainable Strategies was called in to design a zero-discharge system that could be maintained by park personnel.

Sustainable Strategies designed larger systems, using Carousel enhanced composting toilets based on a Norwegian design that has proven most successful in studies in Scandinavia and the United States. Each unit contains four chambers that are used interchangeably as they fill up. This batch approach speeds the biological decomposition process and allows for full biological decomposition, so that what is removed is a fully processed and stable end-product called humus.

Extra liquid from the process is drained to Wastewater Gardens located between the two toilet rooms.

This system is now being considered for installation in homes in Palau.

Greenpeace Toilet, Yap (& Kosrae and Pohnpei, Micronesia)
In the early 1990s, Greenpeace contracted Sustainable Strategies to design and conduct (with the Center for Clean Development) an ecological zero-waste-discharge toilet system to help address sewage pollution in the Pacific islands. Three systems were designed and demonstrated through local construction workshops on the islands of Yap, Kosrae, Pohnpei, and Palau.

This system, now often called "the Greenpeace Toilet" (although its design has been simplified; this newer version is called the "CEPP Twin-Bin with Net Composting Toilet System"), was constructed with YapCAP on an outer island for use by a household. In this system, one side is used at a time. 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.

Improving on past designs, Sustainable Strategies optimized the aeration features and engineered air-intakes and exhaust chimney sizes that promote air and vapor throughput without power.

A follow-up visit to the three islands in 1997 found that the site-built system had been most successfully adopted in Pohnpei, where the local utility was involved in its promotion. On Pohnpei, several systems had been independently built, including one for visitors to Nan Madol, an ancient stone city.

Fiji and Samoa Community Systems (Drawbacks)
In 1996, the Fiji School of Medicine, through a grant from the South Pacific Commission (SPC), conducted a composting toilet construction workshop for students studying to be health agents. This system was built for a community outside of Suva, using the Greenpeace Toilet design.

Visiting in December 2000, we found that it was not used regularly as it was deemed too special for regular use. This is unfortunate, as it was constructed for high-volume capacity. This is a common problem with systems that are "given" to communities without demand by the community and more involvement. This underlines the need for community-based introduction and management programs.

In 1999, CEPP sold the plans for this system to Habitat for Humanity Fiji. It was built by an American mission group, which left off several features due to time limitations. As a result, the system produced odors. It was ultimately closed by the Fiji health department because necessary approvals for construction had not been secured.

Our experiences suggest that ecological sanitation systems are best modeled by willing owner-operators--but not built as service projects at the homes or community sites of ambivalent users. Ultimately, the implementation program is as important as good design.

These two experiences, as well as similar ones in Western Samoa, have prompted the Center for Ecological Pollution Prevention (CEPP) to cease selling the plans, only making them available to community-based organizations through the Pacific EcoSan Center.

Western Samoa
Rota-Loos, a take-off on the Norwegian Carousel design, have been introduced to Western Samoa, with mixed results. Their performance issues here point to the need to consider the composting reactor as a component of a system, not an all-function technology.

United States
This photo shows a Carousel aerobic system in the kitchen pantry of a home in Virginia, USA. It is located there to serve the toilet on the second floor. It is used to supplement the home's small septic system.

Maintenance involves adding some chunky carbon every week. This owner uses a cup of bark every day.

These systems are increasingly installed in upscale homes in the United States and other industrialized countries.

Ecological Zero-Waste-Discharge Systems in the U.S.A.
This home was due to be condemned in 1998, because the local health agent feared that septage from the home's cesspool would into leach the town's water supply, a clear threat to public health.

Sustainable Strategies designed a system much like the one for Lalati: integrated aerobic biofilters, source filtration and Wastewater Garden aerobic planting bed. In this system, the Wastewater Garden enclosed in a greenhouse (for warmth and to keep out precipitation--the warmer the system, the faster the biological transformation process).

Sustainable Strategies has designed a wide variety of such zero-waste-discharge systems for homes, schools and other buildings in the United States.

Next slide: Old Manse historic home in Concord, Mass.

One key to this approach is to filter and pretreat at the source. By keeping effluents separate--not combining them--they are more easily used. Besides the aerobic blackwater biofilter, other source filters include grease interceptors and 30-micron filters.

Urine Diversion
This is a urine-diverting toilet in Sweden. It takes source separation to a new level. Urine contains most of the nitrogen in wastewater--and it is usually sterile in a healthy population. Keeping it out of the wastewater mix allows the aerobic biofilter to perform better (by staying more aerobic). These systems are also manufactured in Mexico.

Wastewater and Washwater Gardens
These aerobic planted (root zone) systems are increasingly installed as it become clearer that leachfield are best designed shallow, so they can 1) be within the root zones of plants and 2) be somewhat aerobic (faster processing).

They can be indoor features (slide: Audubon Center indoor planter bed).
They can be enclosed in moveable structures (slide: plastic dome greenhouse/glasshouse), and they can be used to irrigate gardens (slide: CEPP office garden with tomatoes and runner beans), although many health authorities may forbid use on edible crops.

Washwater/Wastewater Gardens are like wetlands but drier, allowing for more aerobic activity, the faster processing. Pores in these systems provide homes for beneficial bacteria, which destroy pathogens and convert nutrients to a plant usable form.

At the same time, the plants evapotranspire away the water. These ecological systems can be scaled up to serve clusters of homes and even full communities.

Central Community Systems in U.S.A.
This is a Living Machines or Solar Aquatics system which serves a community of 300 homes. It acts as a super-optimized artificial wetland.

Water is reclaimed for flushing toilets or it can be disinfected and used for washing.

Water Hyacinth Large Central System, U.S.A.
This water hyacinth system is a polishing pond that is part of a large wastewater treatment plant in San Diego, California. This pond uses plants to take up the nutrients and further process the effluent (tertiary treatment) before it is discharged to the ocean.

Chuuk Beach Hotel Sign Again (No Swimming in the Sewage!)
The tropics are an ideal environment for ecological systems, with their warm temperatures and availability of hardy plants. Given the detrimental effects of sewage pollution in the Pacific islands, further opportunities for using a variety of systems to use up wastewater and prevent degradation of water supplies and aquatic resources deserve investigation. They are certainly the most economic way to deal with these effluents.

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