According to its developer, ATEC Biodigesters — a social enterprise co-owned by Engineers Without Borders, Australia, and Live and Learn Environmental Education, Cambodia — the biodigester uses an anaerobic chamber to break down organic manure from livestock to produce biogas (CH4 and CO2), which is piped to kitchens as cooking gas. Consequently, the resulting residual sludge is transformed into high-quality organic fertiliser.
“For isolated, rural and less wealthy populations, the benefits of a sustainable anaerobic digestion system are more direct than for urban populations in developed countries.”
Bernadette McCabe, International Energy Agency
While most biodigesters are vulnerable to groundwater pressure, soil expansion or flooding, the polyethylene ATEC biodigesters are designed for installation “in-ground, half in-ground or totally above ground, depending on the local conditions,” says Sophea Sum, ATEC technical services manager.
Developed for use in Cambodia and other countries prone to seasonal flooding, the ATEC biodigester bagged the Google Impact Challenge Award in 2014. Over the past three years, more than 250 units have been installed and ATEC estimates that during a 25-year life cycle, each biodigester will reduce 75 tonnes of greenhouse gases, save over US$6,000 in fuel and yield more than 492 tonnes of fertilisers.
‘Clean energy solutions that utilise natural system principles to unlock the inherent energy in our waste streams have the potential to transform the way we power homes across the world,’ says a press release last month (August) by Small Giants, Australia, one of the new investors.
Bernadette McCabe, bioresources scientist and Australian task leader for the International Energy Agency, says it is important to improve the environmental performance of these technologies without disproportionate increase in costs.
“For isolated, rural and less wealthy populations, the benefits of a sustainable anaerobic digestion system are more direct than for urban populations in developed countries,” says McCabe adding that there is room for improvement given that greenhouse gas emissions from small-scale biogas plants are far higher than the more highly engineered, continuously-stirred tank reactors adopted by developed countries.
Cambodia’s National Biodigester Programme, coordinated by the ministry of agriculture, forestry and fisheries, developed a biodigester market in 2006 and has since been providing micro-loans to families keen on installing the biodigester. The programme, now operating in 14 provinces of Cambodia, provides immense relief from indoor smoke emanating from stoves that burn wood or biomass.
This piece was produced by SciDev.Net’s Asia & Pacific desk.