A water waste plant is an area that is designed for the purpose of cleaning waste water that has been generated by many people living within a given area. After the water has been treated and deemed safe, it is returned to the environment. The by-product, known as sludge, is then disposed of in one of several ways.
Water enters a water waste plant from a network of sewers and storm drains. This water is primarily treated by running through a screen that is designed to trap the largest pieces of waste and separate them. From there, the water enters a series of chambers and tanks which cause grease to float to the top and sediment, or sludge, to sink to the bottom. This first phase of water treatment can remove up to half of the solids and bacteria from incoming waste water, after which chlorine may be added to help kill remaining bacteria.
The next phases in a waste water plant are designed to remove most of the remaining waste from the water. One of the ways this is done is known as the activated sludge process, during which oxygen and sludge containing useful bacteria are injected into the water for the purpose of cleaning it. After the process is complete, the sediment is removed from the water. In a different secondary phase of treating waste water, the water is passed through trickling filter tanks, which are essentially tanks filled with rocks. These rocks are covered with a bacterial slime that renders the bacteria in the waste water harmless.
Sometimes, but rarely, because of the cost, a third phase is employed to remove even more impurities, such as phosphates, from the water. Usually, however, it is after the second phase of cleaning the waste water that it is returned into the environment to eventually find its way back to the plant. Other methods of recycling or disposal are necessary for the sludge and by-products that are created from the water waste plant, usually through composting, incinerating, landfills, and application to farms and other types of land. New methods and technologies are constantly being sought make the processes of recycling water cleaner and more efficient, meaning that less water is lost through filtration.