What is Anaerobic Treatment in wastewater treatment?

Anaerobic digestion converts organic waste into a gaseous energy carrier without consuming (fossil) energy. The process is commonly used in engineered applications for treating organically polluted (industrial) wastewater, organic solid wastes and even sewage. However, its potentials are still largely unrealized, and many industries still install energy-demanding activated sludge processes, in situations where anaerobic technologies could have solved their problems and brought benefits to the industry.
After decades of successful operational experience, nowadays over 5,000 reactors are installed worldwide. Modern high-rate reactors are very compact and allow volumetric loading rates reaching 30-40 kg COD/m3 per day, with an energy output up to 400 MJ/m3 reactor per day. The excess sludge production from these reactors is low in amount and very high in quality. It even has a market value!
For specific industrial wastewaters a more profound understanding of anaerobic conversion processes is required especially if an anaerobic reactor suffers from sudden failures. A well-trained process engineer has a good knowledge base, can perform laboratory tests, and can evaluate why failures occur. With the correct diagnostics, remedial actions can be proposed to regain the full potential benefits of a high-rate anaerobic system.