ETP is a system that removes toxic and non-toxic materials from water, allowing it to be used for a variety
of purposes. A sewage treatment plant (STP) removes contaminants from municipal wastewater or household sewage.
It is mandatory to test and maintain the treatment and removal of contaminants from wastewater prior to its release into the environment. Such treatments in industries, housing colonies, apartments etc, are necessary because wastewater contains harmful chemicals, contaminants or components which pose a threat to both human health and the environment.