Describe the Activated Sludge process of Wastewater Treatment.
The Activated Sludge process is a type of biological wastewater treatment process for treating sewage or industrial wastewaters using aeration and a biological floc composed of bacteria and protozoa. The process involves blowing oxygen or air into raw, unsettled sewage which smashes the solids. The sewage is bubbled, and sewage liquor is discharged into an activated sludge chamber. Under the activated sludge treatment process, the biodegradable organic matter is consumed by a mass of micro-organisms under aerobic conditions. This results in the formation of excess sludge generated from a surplus of living and inert matter in the wastewater. The BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand) of the effluent is reduced maximum to the extent of 80% and 65% respectively.