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Water features:

Refinery wastewater is mainly from circulating water,condensate wastwater,washing water,pump cooling water and tank drainage,its composition is complex,contains oil,ammonia nitrogen,phenol,cyanide,benzene,ketone,ether,sulfur,organophosphorus and metal salts,etc.In order to effectively treat the wastewater,it’s usually divided into oily wastewater(major pollutant is oil,and contains sulphide,volatile phenol,etc,color is grayish brown,with petroleum odor),sulfur bearing wastewater(major pollutant is sulphide,and contains high concentration oil,volatile phenol and ammonia nitrogen,color is dark green,and with strong hydrogen sulfide odor and greater-corrosiveness),alkali wastewater (major pollutants are oil and free alkali,and contains sulfide,volatile phenol and naphthenic acids,color is cream white),salinity wastewater(main pollutants are salt,oil and volatile phenol).

Because the sulfide and volatile phenol in wastewater have great impact on biochemical treatment,all kinds of wastewater must be pretreatmented in workshop before draining into wastewater treatment system.According to experience and fully understanding about refinery  wastewater,we added secondary air flotation and sand filtration process based on "oil separation+air floatation+biochemistry" process,strengthened the removal of wastewater oil,constituted the relatively  intact wastewater treatment system to ensure drainage standard.Effluent achieves petrochemical industry first-level standard of integrated wastewater discharge standard,COD_cr≤50mg / l,BOD₅≤20mg / l,SS≤70mg/l.