For the last three years, we have been transforming our food and toilet waste into cooking gas and liquid fertiliser concentrate (see Living tiny and green) The whole setup is carbon-neutral because biomaterial which was created through photosynthesis pulls carbon out of the atmosphere, and once burned as energy will go back as CO2. The biowaste will turn to methane and CO2 naturally but by adding it to the biogas digester, we are using it to generate energy and prevent methane release.
Essentially, microorganisms inside the bio-digester break down organic matter in the absence of oxygen (anaerobic digestion). The result is biogas and a liquid fertiliser concentrate which can be used on the garden. Double win! We feed the digester between 1 and 2 litres daily and always have enough gas to cook a meal or two per day plus coffees and boil water for tea.
The digester works best in temperatures over 20 degrees celsius so our subtropical climate is perfect and the biogas digester works all year round. The only times we are low on gas or run out are when temperatures drop below 20 degrees celsius for a number of consecutive days (or when we intentionally use it up). In this case, we use our induction cooktop which is solar-powered.
We think that HomeBiogas is an amazing product and one of the most sustainable ways of dealing with food and toilet waste.