Petrochemical wastewater classification

　　Oil refining is the process of physically separating or chemically reacting crude oil to fractionate it into different oil products according to its different boiling points. At the same time, water injection, stripping, condensation, water washing and oil tank water cutting in the oil refining process are the main sources of wastewater. Secondly, wastewater also comes from auxiliary facilities such as laboratories, power stations, air compressor stations and circulating water fields, as well as living facilities such as canteens and offices. According to the characteristics of water quality, wastewater is divided into the following types, which are introduced by Xiaobian:

　　1. Production wastewater

　　Mainly comes from circulating water field cooling water discharge, boiler water discharge, oil tank spray cooling water and unpolluted ground rainwater, etc. This type of wastewater is rarely polluted, and the general COD value is less than 60mg/L, which meets the requirements of national or local emission standards.

　　2. Domestic sewage

　　Mainly comes from the drainage of living auxiliary facilities, such as office building toilets, canteens, etc. The feces and E. coli in them pollute the water body. The main pollutants in sewage are BOD and E. coli. Usually discharged into sewage treatment plants for unified treatment.

　　3. Non-polluted wastewater (assuming clean water)

　　Polluted wastewater mainly comes from circulating water field sewage, non-filler cooling water of pumps, air compressor cooling water, cable trench drainage, non-polluted ground rainwater, and boiler sewage neutralization and treatment drainage. Among them, the main pollutants in circulating water sewage and boiler sewage are salt and certain water quality stabilizers