A wastewater treatment plant(wwtp plant) or Wastewater Treatment Plant Effluent cleans sewage and water so that they can be returned to the environment. These plants remove solids and pollutants, break down organic matter and restore the oxygen content of treated water. They achieve these results through four sets of operations: preliminary, primary, secondary and sludge treatments. Normally, a network of sewers connected to homes, commercial buildings, schools and street grates delivers waste water and solids to a treatment plant's collection tanks and basins in a never-ending flow. Effluent treatment plant and wastewater treatment was also called etp and wwtp plant.