A photo of the anaerobic lagoon at the Cal Poly Dairy taken in 2003. The microturbine and other equipment used to generate electricity can be seen on the right.

Anaerobic lagoons are used to dispose of animal waste, particularly that of cows and pigs. The waste is washed into the lagoon by flushing the animal pens with water. Solid waste, particularly the fibrous type of cows, is sometimes separated before the wastewater enters the lagoon to prevent the buildup of solid material. Anaerobic organisms naturally present in the manure and the environment decompose the waste in the anaerobic conditions of the lagoon. California Polytechnic State University California Polytechnic State University, San Luis Obispo, popularly known as Cal Poly, is a public coeducational university located in San Luis Obispo, California. ... This mid bay barrier in Narrabeen, a suburb of Sydney (Australia), has blocked what used to be a bay to form a lagoon. ... Wastewater is any water that has been adversely affected in quality by any anthropogenic influence. ... An anaerobic organism or anaerobe is any organism that does not require oxygen for growth. ... Animal manure is often a mixture of animals faeces and bedding straw, as in this example from a stable. ... Anaerobic is a technical word which literally means without air, as opposed to aerobic. ...

Areas with cold winters are inappropriate for anaerobic lagoons because the activity of the microorganisms is highly dependent on temperature. It is critical to have the proper size for the lagoon, with volume being more important than surface area. A minimum of two meters is necessary for anaerobic conditions, but the depth should not exceed 6 meters. Sometimes a secondary lagoon is used to accept wastes while the primary lagoon is undergoing maintenance or for other purposes. A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye). ...

If the anaerobic lagoon system is being used for energy production, the primary lagoon has a cover floating on the surface of the water. The cover captures the biogas produced by anaerobic bacteria. The gas produced by anaerobic lagoons is 50 to 75% methane, with carbon dioxide making up most of the rest. The gas is usually used to produce electricity using a microturbine or reciprocating engine, but it can also be used for water or space heating. The gas usually undergoes pretreatment, particularly dehydration, prior to combustion. Sometimes the carbon dioxide, which is incombustible, is also removed. Biogas, also called digester gas, typically refers to methane produced by the fermentation of organic matter including manure, wastewater sludge, municipal solid waste, or any other biodegradable feedstock, under anaerobic conditions. ... An anaerobic organism or anaerobe is any organism that does not require oxygen. ... R-phrases S-phrases , , , Flash point −188 °C Autoignition temperature 537 °C Explosive limits 5–15% Supplementary data page Structure and properties Thermodynamic data Spectral data UV, IR, NMR, MS Related compounds Related alkanes Ethane Propane Related compounds Methanol Chloromethane Except where noted otherwise, data are given for materials in... Carbon dioxide is an atmospheric gas comprised of one carbon and two oxygen atoms. ... Lightning strikes during a night-time thunderstorm. ... This machine has a single-stage radial compressor and turbine, a recuperator, and foil bearings. ... Components of a typical, four stroke cycle, DOHC piston engine. ... Dehydration is the removal of water (hydor in ancient Greek) from an object. ...

See also

• Agricultural wastewater treatment
• Anaerobic digestion
• Sewage treatment