The anaerobic system is a proven and widely accepted technology used to treat a wide range of waste water such as palm oil mill effluent (POME), food processing waste, pharmaceutical waste and brewery waste. It has the capability to treat waste water with very high organic content such as waste water with COD level as high as 30,000 mg/L.

In an aerobic reactor, waste water enters from the bottom and flows to the top in an upward direction. The organic matters in the waste water are decomposed in the state-of-art anaerobic process as the waste water flows through the reactor. The decomposition process leads to the formation of organic acids and methane gas in two different layers in the reactor. The bottom layer is the place where organic acids are formed. The reaction which generates the methane gas takes place at granular sludge above the bottom layer. Anaerobic technology generates significantly less sludge as compared to the aerobic process and does not require air or oxygen supply for treatment of waste water.

Anaerobic technology is used generally in secondary waste water treatment when the incoming BOD and COD parameters are high. In biological waste water treatment design, Sequential Batch Reactor (SBR) system is normally selected as its post treatment unit in oleo-chemical industry. While anaerobic process reduces BOD and COD significantly, SBR acts as polishing unit to ensure the effluent meeting authority's preset standard.

Advantage of anaerobic technology includes: