The most common wastewater treatment methods in developed countries are centralized aerobic wastewater
treatment plants and lagoons for both domestic and industrial wastewater. To avoid high discharge fees or to
meet regulatory standards, many large industrial facilities pre-treat their wastewater before releasing it into the
sewage system. Domestic wastewater may also be treated in on-site septic systems. These are advanced systems
that may treat wastewater from one or several households. They consist of an anaerobic underground tank and a
drainage field for the treatment of effluent from the tank. Some developed countries continue to dispose of
untreated domestic wastewater via an outfall or pipeline into a water body, such as the ocean