Research progress of coagulation air flotation treatment system for petroleum and petrochemical wastewater

With the increasing moisture content of oil and gas in the main block and the further development of unconventional oil and gas resources，the amount of wastewater associated with oil and gas exploitation is increasing. Due to the continuous evolution of oil and gas extraction technology，wastewater quality exhibits characteristics of high oil content and strong emulsification stability，high suspended solids content and reduced suspended solids density. The removal of emulsified oil，dispersed oil and light suspended solids has become a key step in the treatment of oily wastewater. In this paper，the principles and influencing factors of coagulation and air flotation for oil removal were summarized. The research status of coagulation and air flotation systems were reviewed，including research progress on the generation of air flotation bubbles，the structure of air flotation tanks，and the coupling process of air flotation. On this basis，combining the swirl field with the eddy current field，and strengthening the degumming and coalescence separation efficiency of the composite functional pharmaceutical system in the eddy current field was proposed. The development and application of the coagulation air flotation reaction system integrating oxidation，degumming，flocculation，air flotation and separation would be the development trend of oil and gas field wastewater treatment in the future.