Anaerobic Process Principle:
Anaerobic treatment is efficient method for treating industrial effluent water. It uses anaerobic bacteria to convert organic pollutants or chemical oxygen demand into biogas. i.e. it is a biological digestion process through which bacteria breakdown organic matter in the absence of oxygen in closed vessel. This process consists of two stages :
An Acidification phase - anaerobes breakdown complex organic compounds into simpler, short chain volatile organic acids.
Methane production phase - anaerobes synthesize organic acids to form acetate, CO2, H2 and anaerobic microorganism's act upon newly formed molecules to form CH4 and CO2.
Microbial reactions take place in the absence of molecular/ free oxygen, Reactions products are carbon dioxide, methane and excess biomass. It reduces BOD, COD and TSS as well as produce biogas as byproduct.
Applications:
- Net Sludge Yield: Relatively low
- Waste water with medium to high organic impurities (COD > 1000 ppm) and easily biodegradable waste water e.g. food and beverage waste water rich in starch/sugar/alcohol
- Post Treatment : Invariably followed by aerobic treatment
Example Technologies:
Continuously stirred tank reactor/digester, Up flow Anaerobic sludge Blanket, Ultra High Rate Fluidized Bed reactors etc.