Methane production by anaerobic digestion of wastewater and solid wastes

Anaerobic conversion of organic materials and pollutants is an established technology for environmental protection through the treatment of wastes and wastewater. The end product is biogas –a mixture of methane and carbon dioxide–, which is a useful, renewable energy source. Anaerobic digestion is a technologically simple process, with a low energy requirement, used to convert organic material from a wide range of wastewater types, solid wastes and biomass into methane. A much wider application of the technology is desirable in the current endeavours towards sustainable development and renewable energy production. In the 1980’s several projects were initiated in The Netherlands to produce biogas from wastes. Many projects were terminated due to insufficient economic viability. Currently, the production of methane from wastes is receiving renewed attention as it can potentially reduce CO2 emissions via the production of renewable energy and limit the emission of the greenhouse gas methane from especially animal manure. This trend is supported by the growing market demand for ‘green’ energy and by the substantial optimisation of anaerobic digestion technologies in the past decades, especially the development of modern ‘high rate’ and co-digestion systems.