Aerobic treatment systems is based on a biological process operated and controlled under aerobic conditions (with aeration) that effectively treats COD, BOD and VSS into water, carbon dioxide and new biomass.
The sewage or waste water/effluent from industrial operations contains organic impurities. Thus sewage or industrial waste water cannot be directly discharged to the environment. The organic impurities present will consume dissolved oxygen from the receiving bodies and make the receiving body unsafe for drinking use and survival of aquatic life. For safe discharge of sewage/industrial waste water to the environment or receiving body, it is very much essential to treat the sewage/industrial waste water.
For treating sewage/industrial effluent for their organic impurities generally aerobic biological treatment is used. The major process used worldwide is activated sludge process. It is an aerobic biological process that utilizes microorganisms such as bacteria, and protozoa for the decomposition of organic matter. This process has been named so since it involves the production of an activated mass of microorganisms which effectively stabilize the organic content of wastes in presence of oxygen and convert them to carbon dioxide and water which are safe to be disposed off in the environment. This is effectively achieved by a series of metabolic reactions carried out by the microorganisms.
Types of aerobic biological treatment: