adminThe Herald, April 27, 1983
AS the advertisement says, gas is clean and convenient and it certainly beats spending several hours a day looking for firewood.
For the Zenda family, who farm 3 ha at Chishawasha Mission near Harare, the firewood collecting is almost a thing of the past.
They have got their own Chinese-style gas plant fuelled with four buckets of cow dung and water slurry each day.
And as Cde Michael Zenda owns 15 cattle, fuel is a little problem. The generator, one of the first of its type in Zimbabwe, was built 2 years ago in just four weeks under the direction of a Jesuit priest, Fr Brian MacGarry.
It is a major help, Cde Francisca Zenda said. Much of the family’s food is now cooked on a simple home-made gas stove.
The slurry is poured into the hole nearest the hut. The digested residue, a superb fertilizer, is drawn from the front hole and used on the Zendas’ vegetables and crops.
The Central hole is a water seal, ensuring the lid of the digester remains firmly in place and none of the methane gas escapes and no air enters. The process must take place in the absence of oxygen.
Fr MacGarry said the main problem in building the digester was ensuring the underground walls were gas tight.
Two inner tubes from bus tyres, under the eaves, are a local improvement by Fr MacGarry. Besides helping to store some of the gas under low pressure, they also help eradicate rapid pressure changes.
The Chinese-style digester has a fixed volume, and as more gas is produced, the pressure rises.
The Zendas’ plant simply uses bricks, cement, sand, a bit of lime, bitumen paint and a few meters of piping.
Such a plant could also provide gas for lighting and for a gas fridge and could be a boon in areas where wood is short and fuel available.
LESSONS FOR TODAY
◆ Renewable energy is the future, because not only is it clean and convenient, but it is also cheap and sustainable.
◆ The use of bio-digesters especially in the rural areas is key to dealing with problems such as deforestation.
◆ In Zimbabwe, we have the National Domestic Biogas Programme that is being implemented in partnership with HIVOS, Ministry of Energy and Power Development, Ministry of Agriculture, Mechanisation and Irrigation Development and Renewable Energy Fund, SNV promotes biogas to provide access to clean energy for cooking, lighting and productive use in areas such as Insiza, Chegutu, Goromonzi and Mvuma.
◆ Increased use on bio-gas is one of the ways that the country is promoting to help lessen demand for electricity.
Online Reporter