Sewage-a problem to not

be treated lightly

By Sophie Foster Hildebrand

FORGET rising sea levels and deforesta tion for the moment. The Pacific’s biggest environmental problem of this decade is something in everyone’s backyard sewage.

And it is this problem that a project to introduce compost toilets to the region is attempting to address.

A report promoting “sustainable strategies” for controlling waste, by David Del Porto, says nearly every Pacific Island nation has identified critical environmental and public health problems resulting from the disposal of human excrement.

These, he says, have indfcided algae blooms and eutrophication in lagoons, dying reefs, contaminated drinking water wells and outbreaks of gastro-intestinal disease, Lep tospirosis and cholera.

“The causes of this pollution include overflowing latrines and privies, water-sealed toilet, septic systems, piggeries and sewage treatment plans as well as the complete lack of sanitation facilities in some places,” Del Porto continues.

Even the South Pacific Regional Envi ronment Programme (SPREP) has said that “disposal of solid and liquid wastes (particu larly of human excreta and household garbage in urban area), which have long plagued the Pacific, emerge now as perhaps the foremost regional environmental problem of the decade.”

Del Porto cites a Land-Based Pollu tants Inventory for the South Pacific Region which estimated that 21,675 tonnes of BOD, 12,252 tonnes of suspended solids, 10,499 tonnes of nitrogen and 1,250 tonnes of phos phorous enter the South Pacific Ocean each year from domestic wastewater, making it the major source of these pollutants in the region.

The Federated States of Micronesia’s

(FSM) National Environmental Management

Strategy (NEMS) calls the disposal of sewage along with solid wastes “one of the most trou blesome environmental problems...” they face, and cites increasing marine pollution from sewage in almost all state centres.

“A number of studies have found sewage pollution to be adversely affecting

coral reefs in the FSM, especially when dis charged into lagoons with low circulation.

Central wastewater treatment plants con structed with funds from the US environmen tal Protection Agency in Pohnpei and in Chuuk States have failed due to lack of trained personnel and funding for mainte nance,” he says.

The problem also extends to the Mar shall islands where stagnation of lagoon waters, reef degradation and fish kills result ing from the low levels of oxygen have been well documented over the years. Additionally, red tides plague the lagoon waters adjacent to

Majuro.

What’s worrying is that the Marshall Island EPA estimated that over 75 per cent of the rural wells tested were contaminated with fecal coliform and other bacteria. Cholera, typhoid, and various diarrheal disorders all occur.

With very little industry present, most of these problems are blamed on domestic sewage, with the greatest contamination prob lems believed to be from pit latrines, septic tanks and the complete lack of sanitation facilities for 60 per cent of rural households.

Del Porto says that “even the best of these systems in the most favorable soils con ditions allow significant amounts of nutrients and pathogens into the surrounding environ ment, and the soil characteristics and high water table typically found on atolls signifi cantly inhibits treatment”

In addition, the lack of proper mainte nance, due to a lack of equipment to pump out septic tanks, is likely to have degraded the performance of these systems even further.

Forty percent of the population in the Repub lic of Palau is served by a secondary sewage treatment plant in the Koror, which is general

ly thought to provide adequate treatment.

However the Koror State government has recently expressed concern over the possible contamination of Malakal Harbor, into which

the plant discharges.

“Some low-lying areas served by the system experience periodic back-flows of sewage which run into mangrove areas due to mechanical failures with pumps and electrical

power outages. In other low lying areas not covered by the sewer system, septic tanks and latrines are used which also overflow, impact ing marine water quality,” the report says.

It says that although there have been an increasing number of septic systems installed as part of a rural sanitation program funded by the United States, there is anecdotal evidence that they may not be very effective.

“Many of the septic tank leach fields may not be of adequate size. In addition, a number of the systems are not used at all, as some families prefer instead to use latrines since the actual toilets and enclosures are not provided with the septic tanks as part of the program,” it says.

In an attempt to combat these prob lems, David Del Porto and Lowell Robinson of Sustainable Strategies, have developed and successfully demonstrated compost toilets on several developing island nations of the Pacif ic.

But, according to Del Porto, because US funding to the Micronesian islands is dry ing up now, efforts to build demonstration projects and promote them - “very key with any new technology” - have slowed to a crawl.

He says that even Greenpeace is no longer funding such projects, due to its “radi cal shift in focus”. Sustainable Strategies has now started a nonprofit organisation to contin ue the work.

The carousel compost toilet system uses a four-chambered fibreglass waste col lection tank for batch digestion, which rotates on a pivot inside an outer container.

One chamber is located directly below the toilet pedestal and filled over the course of several months’ usage. When it is filled, the tank is rotated so that this first chamber is iso lated from receiving fresh wastes, and the next chamber is positioned below the pedestal.

After all four chambers have been filled (about two years with recommended useage) the waste in the first chamber is com pletely digested into humus and can be removed so that the chamber is ready to be used again.

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The unit can be furnished with an elec tric fan to ensure adequate airflow through the ventilation system, and an optional heater is available to maintain temperatures for micro bial activity in temperate climates.

Aside from normal cleaning, each of the demonstration models requires a minimum of routine maintenance to ensure proper con ditions for aerobic digestion.

What this means is that all you have to do is drop a small amount of leaves or shred ded coconut husks down the toilet after each use, providing a source of carbon for the aer obic bacteria, as well as a spongy-texture.

What’s interesting for the developers of the Carousel Compost Toilet system is that observations suggest that “the Pacific islands climate has significantly enhanced the perfor mance of the treatment process over what is typically experienced in temperate climates”.

“Although all of the chambers of a small version ol the Carousel would be expected to be tilled after a year’s use in a more temperate (cooler) country, this process took 2 1/2 years in Yap! A significant increase in capacity,” the report said.

Del Porto says in Palau, where com posting toilets are located in a park on the Rock Islands, it is “a big success”.

“We’ve been told by several visitors that the park officials proudly show them to anyone who is interested”.

In Pohnpei, the demo units were doing well, he says. “Some needed some minor adjustments. What’s great is that we saw peo

ple independently building composting toilets,

including the Nan Markee.”

He says the Suva, Fiji unit is said to be doing well. “An eco-resort, Lalati, is installing

several composting toilets designed by this

firm. Also, Habitat for Humanity is going to be building some in a few weeks. Other com posting toilets are in Samoa, Kiribati, Papua New Guinea and Kosrae. Del Porto says that it is hard to promote a very new way of manag ing waste without a steady campaign of demonstration projects and an information programme.

But he says that the success of the operating projects has shown “not only that these technologies can work in developing island nations of the Pacific’s climate, but that people readily accept them and are willing and able to perform the simple routine mainte nance which they require.”

Perhaps with a bit more promotion, compost toilets may soon help improve the conditions that many marine life in the islands have to survive in. ■