A sewage treatment plant is required for all residential and commercial areas. This process is similar to that of a septic tank. However, some additional mechanical components in the former prove a better choice resulting in cleaner and more environment-friendly effluent.Sewage treatment, also known as wastewater treatment, is used to remove contaminants from municipal wastewater. Various physical, biological, and chemical processes are used to treat water.Small scale wastewater treatment is basically for domestic sewage. This is considered as the secondary treatment specifically designed to remove biological contaminants from water. Usual sources of these impurities are food waste, human waste, detergent, soap, etc.Many sewage treatment plants in India have been constructed through government funding schemes such as the GAP and the YAP. ASP, UASB, and a series of WSP were the most preferred treatment technologies in earlier days.