The digester uses a variety of domestic waste products such as animal manure, garden clippings, kitchen waste and toilet runoff to produce pressurised biogas that can be used for cooking, heating and lighting.
“The system delivers gas ‘smell free’ (when burned) and pressurised to your point of consumption without any pumps or external electricity required. It is a global innovation designed by South African Engineers and we are very happy about that”, says Weber.
How does the unit work?
According to Weber the bio-digester was coined the “little green monster” because it “eats all organic waste and breathes fire”.
“The biogas digester is installed within your existing effluent line (black water only, grey water should be separated) with a unit to introduce additional organic waste. Through an anaerobic bacterial process the organic waste is broken down and methane gas is produced”, explains Weber.
How much biogas is produced?
“The Little Green Monster bio-digester has a gas storage capacity of 500 litres at normal pressure and temperature. Thus if the unit is fed and managed optimally, 500 litres of biogas can be utilised twice a day. This equates to an estimated maximum daily biogas capacity of 1000 litres. This equates to a total energy content of 7 kWh (units) per day which is enough in terms of electrical equivalent to heat up a geyser to produce enough hot water for two people to have a 10 minute shower using a 10 litre/minute water heater and enough to burn a domestic size gas hob for 3-4 hours”, adds Weber.
How to ensure that your system works efficiently
According to Weber, the bio-digester is a living system with bacteria and needs to be seen similarly to a tank with fish. “It needs to be fed at least four times per week and within limits because over or under feeding will poison or starve the system”, he says. A detailed guideline document on how to operate and maintain the system can be obtained from Weber.