Turning sewage into money and power

by Ray Obiero | @ray_obiero | Thomson Reuters Foundation
Monday, 18 November 2013 13:03 GMT

A boy disposes of raw sewage into a stream in the sprawling Kibera slum, one of the largest and poorest slums in Africa and home to about 1 million people, in Kenya's capital Nairobi on August 26, 2011. REUTERS/Thomas Mukoya

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Biogas and electricity from human sewage could help solve Kenya’s budget problems, and many others

It is no secret that Kenya faces problems handling human waste. Earlier this year, news emerged of raw sewage being used to grow vegetables and food for Nairobi residents – evidence of the scale of the danger posed by Nairobi’s inadequate sewer system.

Nairobi isn’t the only place in Kenya with problems. Most local – or county - governments have no effective way of dealing with raw sewage. Either most of the residents in urban areas are not served by any sewer system, or those that are have to contend with systems that are old and broken down.

This often leads to a variety of health hazards - not least the threat of diseases such as cholera and typhoid.

But there could be a way to deal with urban sewage that also produces energy. Nyeri county government and Karatina University, located in the county, intend to generate biogas at the local municipal sewer works and use that energy to power water pumps for the municipal water company.

According to ILF Consulting Engineers, a German consulting firm working on the project, liquid running in the county’s sewer pipes can be used to run turbines to directly generate electricity and more electricity can be derived from biogas generated from the sewage.

COST SAVINGS

The whole project is located near the water treatment plants so that the electricity generated can be used to pump water to residents. The project is estimated to cost 100 million Kenyan shillings ($1.15 million) and is expected to save 1.1 million Kenyan shillings ($12,700) per month that the county government pays in electricity bills for its water treatment and pumping costs.

Excess biogas generated would be sold to local households for domestic use, backers say, and eventually excess electricity produced could also be sold. For now, the project will only generate enough electricity to power the water systems because, until Kenya’s parliament approves the end of the country’s electricity distribution monopoly, Nyeri county government cannot sell electricity directly to local residents.

The sludge leftover after biogas production can be used as organic fertilizer and sold to local farmers, project supporters say, and students at the university will study the project for practical lessons and research experience.

 

 

SOLVING MULTIPLE PROBLEMS

Kenya has 47 counties and none can boast of having an effective sewer system. But by looking at the sewer problem as an income opportunity, county governments could perhaps tackle a myriad of issues at once.

Nairobi County, for instance, has some of the oldest sewer works in the country. Overflows, burst pipes, and illegal sewer diversion for agricultural irrigation are among the problems faced.

So what is preventing more county governments from initiating such inventive projects to tackle sewer problems and energy shortages? Previously, red tape and vested interests made sure that such projects never got off the ground. But now that county governments are required to raise some of their budget locally, they are being forced to look for new ways to solve problems in their areas, and keep voters happy.

Forests would be a big beneficiary of such efforts spreading. Most of the marginalized communities in urban areas use charcoal-powered stoves and or kerosene stoves to cook.  This has always placed a huge demand on local forests for charcoal production – and has led the government to impose bans on charcoal burning and transportation from certain areas in order to give forests time to regenerate.

The sewage biogas project could help, in terms of environmental and health policies but also the income that county governments could earn. Also this would attract the investment needed to modernize the sewer systems in the country, and allow farmers to use treated sewage as fertilizer, going a long toward helping domestic food production lower input costs.

Ray Obiero is a physics graduate of Kenya’s Egerton University and blogs for AlertNet Climate on climate change issues.

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