Sewage Treatment Plant (STP)
A sewage treatment plant is a facility designed to receive the wastewater from domestic sources and to remove materials that damage water quality and threaten public health and safety when discharged into receiving streams or bodies of water. The substances removed are classified into four basic areas:
1) solids from human waste and other sources;
2) greases and fats;
3) dissolved pollutants from human waste and decomposition products; and
4) dangerous microorganisms.