Abstract: The saline wastewater treated by a petrochemical enterprise mainly consists of refinery saline effluent and saline effluent generated by low-salinity water regeneration units. The saline wastewater treatment system is functionally divided into refinery saline effluent treatment unit, effluent upgrading unit #1 and effluent upgrading unit #2. With the adjustment of the industrial structure of upstream production facilities and the continuous development of clean production work, variations have emerged in both flow rates and quality of discharged water, with operational parameters at certain facilities deviating substantially from design specifications. As the running time increases, some device defects are also exposed. In order to reduce consumption and ensure stable operation, optimizations were implemented for the two-stage DGF (dissolved gas flotation) system, two-stage forced aeration basin and wastewater polishing unit process,good results have been achieved.

Key words: dissolved gas flotation, denitrification, optimization