Blog Post 9
Post your response to the blog discussing why refinery wastewater cannot be treated in municipal wastewater treatment plants.
Water and steam are used for treatment in huge quantities in petroleum refining. Of course a refinery thus generates a lot of waste water. The waste water faces many different levels of contamination based upon its usage within the refinery. The steam or water that comes into direct contact with the hydrocarbons or crude oil is the most highly contaminated and should be treated separately on its own. In order to have the best and most efficient water treatment process the key is segregation of the waste streams. This is because of the different forms of contamination. For example, desalting you don’t really need to use fresh water, you can use waste water that is contaminated with hydrocarbons but doesn’t contain salt to remove salt from crude oil as the very first process before undergoing distillation. Process water contaminated with hydrocarbons can be used effectively for desalting instead of fresh water. Different wastewater streams have different levels and different kinds of contaminants. Combining them would increase the load on wastewater treatment facilities.
The units within a refinery that generate the largest amount of wastewater are desalting, distillation, cracking processes, coking, heat exchangers, and storage tanks The four types of refinery wastewater include cooling water, process water and steam, storm water, and sanitary sewage water. Storm water may be contaminated because of incidental exposure to pollutant sources on refinery surfaces and other accidental spills such as oil from automobiles. Pollutants found in the wastewater streams include hydrocarbons that have a particular concern for toxic aromatic compounds, heteroatom compounds, dissolved gases, acids, and suspended or dissolved solids. Cooling water and sanitary sewage water are forms that may not require much treatment before they are sent to public water treatment facilities due to their contamination levels. The most important thing to keep in mind is to avoid mixing different types of wastewater streams to reduce the load on the treatment units.