Sewage treatment
Hazardous waste, chemical waste, industrial solid waste and municipal solid waste are classifications of wastes used by governments in different countries. Sewage treatment plants can treat some industrial wastes, i.e. those consisting of conventional pollutants such as biochemical oxygen demand (BOD). Industrial wastes containing toxic pollutants or high concentrations of other pollutants (such as ammonia) require specialized treatment systems. ("See" Industrial wastewater treatment).