Local entrepreneur’s biogas digesters solution to energy and sewage needs 

By Nyaradzo Nyere

Hundreds of houses are scattered haphazardly. Some are complete; others are under construction while the majority are cottages popularly known locally as “boyskies”.

The area is not formally planned, hence there are no sewage and power lines. Most of the residents rely on firewood for cooking. The majority have pit latrines while those who earn more use septic tanks to manage sewage waste. 

Gilbert Kazingizi lives in Hopley area on the outskirts of Zimbabwe’s capital, Harare, and constructs biogas digesters from scratch. He says he started this business in 2012 after realising that the development of sewage control services and power supply for his neighbour was very slow.

“We don’t have sewage services and no electricity supply. Firewood is expensive and it comes at a cost of cutting down trees,” he said.

Kazingizi said he constructs small to large-scale bio-digesters. A small digester costs between $300 to $500 to construct while a larger-scale bio-gas digester costs US$4,000 to $8,000, depending on its size.

Most of his clients are from his neighbourhood and other areas that do not have sewerage reticulation and power supply. Kazingizi constructs an average of 10 bio-digesters per year, but this year business has been slow, he cannot travel because of the novel coronavirus, he has only built two so far.

 Kazingizi’s labour charges range from US$400 for a small four-cubic-meter bio-digester and US$4,000 for large bio-digesters which measure around 50 cubic meters.

According to a report by SNV – Netherlands, an international development non-governmental organisation that works in the area of renewable energy technologies, biogas is a simple technology to produce clean, alternative and easily accessible renewable energy from biomass. 

Biogas is an energy product derived from organic material such as animal dung that is decomposed in the absence of oxygen making a mixture that is mainly made up of methane (gas). The gas can be used directly for cooking and lighting or for generating electricity.

This renewable energy source can help reduce the amount of greenhouse gas emissions put into the air.

“The bio-digester normally works depending on how much waste you feed it. If you don’t feed it enough waste it will not produce sufficient gas,” said Kazingizi.

Peri-urban areas in developing countries are facing serious problems in terms of provision of adequate sanitation facilities, and Zimbabwe is not spared from these challenges.  The country also faces problems of garbage disposal and sewage treatment, according to research by the International Journal of Renewable Energy Development.

The report further says in Zimbabwe these mounting problems have resulted in several outbreaks of waterborne diseases, such as cholera, dysentery and typhoid, particularly in the peri-urban high-density suburbs of Harare. 

According to 2018 data from the World Health Organisation, 8,535 cumulative cases and 50 cholera deaths were recorded in Harare’s suburbs.  Most of the peri-urban high-density, low-income suburbs are not connected to the central water reticulation or sewer systems, and the national electricity grid. 

For years, Zimbabwe has been facing extensive power supply challenges and residents have turned to using firewood and other methods for cooking.

Kazingizi’s work is helping to curb the problem of waste management and demonstrating how decentralised biogas digesters can provide clean, reliable and alternative energy to marginalised urban and rural communities. This contributes towards reducing deforestation while improving livelihoods through productive enterprises and agricultural production from biogas substrate.

With electricity, farmers can power workshops to repair tools, and grinding mills, which vastly increase their productivity.

Meanwhile, Inay Longwe, is a farmer based at Nyagore Farm in Sandringham, in Mashonaland West Province. He said he is benefitting from a bio-digester built by Kazingizi.

“I realised that if we continued to cut down indigenous trees at my farm it would cause serious environmental degradation and at the same time it takes many years to grow these indigenous trees,” he said.

Longwe said he feeds his bio-digester with cow dung, human waste and chicken manure and uses the gas for cooking at his farm, “We are happy that we are preserving the environment while benefitting from an energy source,” he said.

Zimbabwe’s Environmental Management Agency says that 50 million trees are disappearing from the country’s forests every year. Apart from preserving the environment, the bio-digesters are helping other citizens save money.

“In a month, l used to buy 15kgs of Liquified Petroleum Gas (LP Gas) which is priced at US$1,50 per kg, but now l don’t buy this gas if my bio-digester is well fed,” said Farai Nyoka a resident of Glen Forest, a suburb in Harare with no sewage facilities  while some parts of it also do not have connections to water. 

Nyoka said he feeds his bio-digester with kitchen waste from his workplace as well as human waste.

“It’s a brilliant idea to use bio-digesters if only more and more people could see the importance,” said Nyoka.

Post Author: Chido Luciasi

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.