Management of organic waste is a major dilemma for developing countries. It generates unpleasant odors and helps rats, flies, bugs and mosquitoes multiply and spread diseases. As it decomposes, organic waste generates methane, a gas that contributes significantly to global warming. Last year Daniel Hoornweg, Perinaz Bhada-Tata and Chris Kennedy predicted in an article in the magazine Nature that the global rate of solid waste generation is expected to triple by 2100. This is bad news because if the investment for solid waste management in developing countries remains as low as it is today, the world is at risk of irreversible environmental deterioration.
Reduce, Reuse, Recycle… Recover. As the population in large cities worldwide grows, waste management becomes an even bigger challenge. Recycling programs can divert large amounts of materials from landfills but some garbage still needs to be disposed of in landfills or Energy From Waste (EFW) sites. EFW facilities are capable of recovering energy from garbage that would otherwise be unused in landfills.
EFW and landfill gas capture systems operate on similar principles: produce steam to turn a turbine which generates electricity. The difference is the fuel used to produce the steam. Landfill gas based electricity generation relies on methane from the decomposition of organic material, while EFW facilities combust the solid waste. Both are good options as they prevent methane gas from escaping into the atmosphere. Methane has a global warming potential 72 times that of carbon dioxide. Both options sound good, so which is better? The better question is: ‘How much land and money do you have’?