Wastewater is anything from water that flows down the sink or toilet to runoff from snow and rain that enters storm drainage systems. Wastewater treatment processes remove a variety of contaminants from water to make it usable again. The benefits of such treatment depend on the nature of the contaminants in the water and the end use of the water treated. Clean Water Water is a renewable resource because it gets purified through evaporation and rain; however, only about 3 percent of the earth's water is potable. Although nature slowly cleans wastewater over time, the main benefit of wastewater treatment is maintaining clean water for reuse. New Research and Improvements Wastewater treatment processes are changing as researchers develop new techniques. Such research leads to improvements in purification, the speed of water treatment and uses for the waste products removed. Development of new processes also saves more energy, time and resourc...