Sewage is anything carried by sewers. Waste water coming from domestic or industrial houses or garbage dumps is generally called sewage. Sometimes, it may even contain rain water and surface run off. The treatment of waste water involves the following six steps:
Water pollution is one of the most serious environmental problems. It occurs when water is contaminated by such substances as human and animal wastes, toxic industrial chemicals, agricultural residues, oil and heat.
Abundant, clean water is necessary for good health. Water pollution is a community problem. It is necessary not to let the industrial waste to find its way to natural waters (rivers, canals and seas) without proper treatment.