In petroleum refining, a large amount of water is used in the refining process. This water is processed using wastewater treatment techniques. Since the amount of water used in refining is so vast, waste water treatment is an integral part of the refining process. There are four different types of waste water; cooling water, process water and steam, storm water and sanitary sewage water. These four types of water carry large amounts of pollutants as well. Pollutants like, liquid hydrocarbons, suspended and dissolved solids, mercaptans, phenols, amines, and cyanides. All of these pollutants are a direct result of the water’s use in the refinery.
There are two types of measurement systems that are used to measure the level of contamination in waste water. Those two types are the Biochemical Oxygen Demand and the Chemical oxygen demand. Biochemical Oxygen Demand measures the amount of oxygen consumed by microorganisms in decomposing organic matter, and the Chemical Oxygen Demand measures the total oxygen consumption by organic and inorganic chemicals present in water.
Refinery waste water however, can’t be treated in municipal waste water treatment plants. This is because the municipal water treatment plants are not capable of processing the contaminants that arise from water that is used in petroleum refining. It is also important to keep the different wastewater streams segregated as the different types of wastewater have different levels of different contaminants. This making the combining of the streams undesirable as the treatment of the water would be much more difficult, placing to high of a strain on the water treatment machinery.
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