Waste treatment refers to the activities required to ensure that waste has the least practicable impact on the environment.
In many countries various forms of waste treatment are required by law.
Agricultural wastewater treatment is treatment and disposal of liquid animal waste, pesticide residues etc.
[1] Industrial wastewater treatment is the treatment of wet wastes from factories, mines, power plants and other commercial facilities.
Alternative systems may use composting processes or processes that separate solid materials by settlement and then convert soluble contaminants into biological sludge and into gases such as carbon dioxide or methane.