The wastewater from refineries can not be treated in regular municipal wastewater treatment plants for a variety of reasons. Municipal wastewater treatment plants are designed to treat wastewater from residential houses. There can also be some rainwater runoff going it to these plants as well. These plants are not equipped to clean the wastewater that would be coming from a refinery. The waste water coming from a refinery is divided into four different types. The types of wastewater are Storm water, sanitary sewer water, cooling water, and the most polluted process water and steam. The process water and steam contains many forms of pollutants that include liquid hydrocarbons, suspended solids, dissolved solids, mercaptans, phenols, amines, and cyanides. These chemicals would not be able to be processed by a municipal wastewater treatment because of the toxicity of some of these compounds. These compounds have to be stripped from the sour water using steam to remove H2S, float/sink density separators, as well as settling tanks to separate heavier oils. After these processes are completed the water can be directed to a wastewater treatment plant where the water can be completely processed. There is also a secondary treatment process that uses microorganism to remove organic compounds from the waste water. This process produces a substance called biocoke.