Wastewater treatment is a process to convert
wastewater - which is water no longer needed or suitable for its most recent use - into an effluent that can be either returned to the
water cycle with minimal
environmental issues or reused. The latter is called
water reclamation and implies avoidance of disposal by use of treated wastewater
effluent for various purposes. Treatment means removing impurities from water being treated; and some methods of treatment are applicable to both water and wastewater. The physical infrastructure used for wastewater treatment is called a "wastewater treatment plant" (WWTP).