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August 21, 2008 | Sci/Environment

Engineer Invents Revolutionary Sanitation System

The Statesman

When Ghana joined the United Nations General Assembly in declaring 2008 the International Year of Sanitation, most thought the year would be spent merely removing the stigma around sanitation issues so that awareness could eventually flourish into solutions. Basically, only a few people imagined a solution was readily available.

Kweku Anno, manager of Anno Engineering Ltd., has developed an environmentally friendly, stench-free way of disposing sewage.

In his keynote address at the launching of Anno's Biofil Digester in June, Professor Ralph Mills-Tettey, registrar of the Architects Registration Council of Ghana, explained that sanitation issues in Ghana are impacting more than just noses (to smell the stench).

"Ghana is witnessing a population explosion in our towns and cities, and sanitation- related inadequacies contributing to poor health are the predisposing factors in over sixty percent of diseases reported", Mills-Tettey said.

Anno observed that advertisements for deworming tablets are rampant in Accra, even in affluent areas.

"This is a problem simply because of the way we have treated the environment", he said.

Since Ghana's partnership with Israel in the 1970s to construct a central sewage system for Accra was terminated prematurely due to political conflict, no major attempts have been made to revolutionize the way sewage is managed.

According to Anno, today only 30% of Ghanaians have a toilet of any kind.  Although that statistic would indicate a slight improvement from the 22.9% recorded by reports released by Ghana's Statistical Services Department in 2003; it is not enough to satisfy Anno and other sanitation experts.

Anno says that of the waste produced by the minority with toilets, only 30% is taken to a facility for treatment. The percentage is likely smaller in rural areas. Areas with high water tables cause septic tanks to fill too rapidly, making proper disposal of contents

expensive. Anno, who lives in a high water table zone himself, says his neighbors have to dislodge their tank twice a week, paying waste management companies GH¢100 each time.

"Because of the expense", Anno said, "most people just dump it into the drain".

The remaining 70% of Ghanaians who don't have a toilet are forced to relieve themselves in the bush, on beaches, in public places, in pit latrines, or using Kumasi Ventilated Improved Pit Latrines.

But, says Anno, many are advocating that the KVIP system, developedat the Kwame Nkrumah University of Science and Technology, be phased out.

"The stench is awful, mostly because of misuse", he noted.

The system, designed for single-family limited use, is often shared by entire communities, making maintenance of the system difficult.

Despite the problems with the KVIP system, the Accra Metropolitan Assembly has declared plans to assist households in installing them to replace pan latrines, which the assembly will ban as of 2010.

According to Mills-Tettey, these measures are not enough. "The fact still remains that we do not have sustainable and environmentally-friendly systems of sewage disposal in this country", he stressed.

Anno's Biofil Digester may be the solution Ghana is looking for.

The system, which uses a simple compressor to pump septic tank contents through a series of filters, frees wastewater of solids and diverts the water back into the soil.  The water, inserted at the surface level of the ground, allows decomposition to occur aerobically, minimizing the stench while returning nutrients to the topsoil.

Anno said that for an average household, a 4-square meter area of dirt would be sufficient and the system would only need to be turned on for about one hour per week.  It eradicates the need for frequent discharging, and stops discharging in open water.

The first model of the system, installed four years ago at a farm across the road from his home, has never had a glitch.

He maintained that the same technology he had applied to the septic system could be used to improve sanitation at all stages of development.  He is currently designing a toilet bowl that will allow waste to fall directly into the filter system, allowing the aerobic decompositionprocess to occur in pit latrines.

Eventually, Anno hopes toilets are installed in areas that don't have them.  In the meantime, however, the Biofil system could improve the quality of life of those who use pan latrines. With the help of the government, the engineer says his units could be placed at vantage points in areas with no toilets.

"People could at least dump their chamber pots inside to minimize stench in an environmentally-friendly way", Anno said.

Behind his home, Anno has installed a smaller version of the Biofil system for food scraps.

"It filters the water, retains the solids, and allows microorganisms to feed on them", Anno said.

Ideally, the Biofil Digester would eliminate the septic system altogether.  Also installed at Anno's home is a toilet that flushes directly into the system, rather than accumulating first in a septic tank. "When water is drained immediately, decomposition occurs up to 30 times faster", he says. And, the end product is less voluminous and more useful. In two years, his direct decomposition system has produced only two buckets of nutrient-rich topsoil.

"The KVIP system cannot be cleaned with water, because it will compromise the system", Anno asserted. "My system can be cleaned every day".

Water will drain off and anaerobic decomposition is prevented.

"One passion that is driving me is that no school should be without a toilet - not one. "How can we teach the next generation hygiene when they have to go to the bush to deposit the waste inside them"? he wondered.

With the help of international funding, one school in Accra was able to have the Biofil Digester installed. Anno hopes that it will only be the first of many.

quot-img-1The regrets are like yesterday: They announce only the future. (Les regrets sont comme hier: - Ils n'annoncent que le futur)

By: Charles de Leusse quot-img-1
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