Along with the development of the petroleum and chemical technology, people gradually realized that some of the production process requirement for water quality is not high, other technological process of sewage can be blended with fresh water to a certain proportion, as the process water. Then, with the progress of water treatment technology, it was found that some process drainage water complex, difficult to handle, and some simple process drainage water quality, according to the different water quality of sewage handling alone, more economic than will be treated as the sewage mixed together.
Petroleum chemical industry is a series of organics processing processes, which are based on petroleum as raw materials, such as cracking, refining, fractionation, reforming and synthesis. Petroleum and chemical products production process, production equipment, the sewage water volume is big, the typical petrochemical sewage containing oil, CODCr, ammonia nitrogen, sulfur, phenol, cyanide, etc of conventional pollutants. At the same time, different enterprises on the basis of different products, produced sewage also contains a variety of organic chemical products with related characteristics of pollutants, such as polycyclic aromatic hydrocarbons, aromatic amine compounds, heterocyclic compounds and so on, resulting in sewage water quality not only complex, and toxic substances. In addition, enterprises open parking and maintenance, such as the source of raw material change production fluctuations can cause sewage water and pollutant content and nature of change, increase the shock load of sewage treatment facilities.
In recent years, water resources have become increasingly tense, and the researchers have treated some of the wastewater in a moderate/deep way, directly as water for other processes. It is reported that in the process of the whole process, the amount of water is about crude oil processing capacity of 20 ~ 50 times, although most of the water can be recycled, but still can produce 0.4 ~ 1.6 times the crude oil processing capacity of sewage.
National governance is becoming more and more attention to the environment, the improvement of environmental standards and regulations gradually put in place and tightened, making polluting enterprises more and more difficult to escape the environmental responsibility and a large number of environmental history debt left by the potential demand, start the new project of new water treatment requirements, as well as the existing energy chemical industry project reconstruction under higher environmental standard requirements, all for the energy chemical industry wastewater treatment scale growing to provide power.