Activated Sludge Sewage Treatment Plant

The process of eliminating impurities from wastewater, especially domestic sewage, is known as sewage treatment. In order to eliminate these impurities and create treated wastewater (also known as treated effluent) that is safe for the environment, it involves physical, chemical, and biological processes. Sewage sludge, a semi-solid waste or slurry that typically results from sewage treatment, requires additional treatment before it can be disposed of or applied to land.

Effluent treatment, which is a more general phrase that can also be used to describe effluent that is solely industrial, is another name for sewage treatment. In order to lessen the pollution load, most cities' sewage treatment plants also receive a part of industrial wastewater that has typically been pretreated at the companies. Stormwater from urban runoff will also be sent to the sewage treatment facility if the sewer system is a combined sewer.

It is possible to treat sewage at its source, a process known as "decentralised" or even "on-site" (in septic tanks, biofilters, or aerobic treatment systems). As an alternative, sewage can be gathered and delivered to a municipal treatment facility via a system of pipes and pump stations. Although the lines separating centralised and decentralised systems might be blurred, this system is referred to as "centralised" (see also sewerage, pipelines, and infrastructure). Both "semi-centralized" and "semi-decentralized" are being used as a result.