Anaerobic digestion is a biological process in which organic wastes are broken down by microorganisms in the absence of oxygen. An anaerobic system can be used for pretreatment prior to discharging to a municipal wastewater treatment plant or before polishing in an aerobic process.

Anaerobic treatment is typically utilized to treat warm, high-strength industrial wastewater containing high concentrations of biodegradable organic matter. This energy-efficient process reliably removes biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solids (TSS) from wastewater.