Page "Water pollution" Paragraph 79

Some industrial facilities generate ordinary domestic sewage that can be treated by municipal facilities.

Industries that generate wastewater with high concentrations of conventional pollutants ( e. g. oil and grease ), toxic pollutants ( e. g. heavy metals, volatile organic compounds ) or other nonconventional pollutants such as ammonia, need specialized treatment systems.

Some of these facilities can install a pre-treatment system to remove the toxic components, and then send the partially treated wastewater to the municipal system.

Industries generating large volumes of wastewater typically operate their own complete on-site treatment systems.