Some industrial facilities generate ordinary domestic sewage that can be treated by municipal facilities. Industries that generate waste water with high concentrations of conventional pollutants (. oil and grease), toxic pollutants (. heavy metals, volatile organic compounds) or other non conventional 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 waste water to the municipal system. Industries generating large volumes of waste water typically operate their own complete on-site treatment systems. .
