text: There are multiple different ways to fix cultural eutrophication with raw sewage being a point source of pollution. For example, sewage treatment plants can be upgraded for biological nutrient removal so that they discharge much less nitrogen and phosphorus to the receiving water body. However, even with good secondary treatment, most final effluents from sewage treatment works contain substantial concentrations of nitrogen as nitrate, nitrite or ammonia. Removal of these nutrients is an expensive and often difficult process.
  Laws regulating the discharge and treatment of sewage have led to dramatic nutrient reductions to surrounding ecosystems. Because a major contributor to the nonpoint source nutrient loading of water bodies is untreated domestic sewage, it is necessary to provide treatment facilities to highly urbanized areas, particularly those in developing countries, in which treatment of domestic waste water is a scarcity. The technology to safely and efficiently reuse wastewater, both from domestic and industrial sources, should be a primary concern for policy regarding eutrophication.