Multiple Technological Barriers Combined with Recycling of Water and Oil in Wastewater Treatment of a Coastal Petrochemical Complex

A research and development project was carried out at a petrochemical complex, located at a distance of about two miles from the Mediterranean coast in the Gulf of Haifa, Israel. The program included: characterization of the wastewater, the main stream as well as lateral streams generated by specific production processes; laboratory and pilot studies of chemical flocculation-dissolved air flotation (DAF); a comparative study of three alternative biological processes: activated sludge, rotating biological contactor (RBC) and aerated ponds (AP); a survey of the biological process occurring in the recirculated cooling water system (RCS) of the industrial complex; conditioning and dewatering of the oily sludges produced by the wastewater treatment facilities and by some other units. Following the research results and conclusions, the developed solution was based on: a) multiple stage treatment, achieved by combining physico-chemical and biological processes, creating several technological barriers in order to avoid uncontrolled emissions into the marine environment; b) maximal recycling of water(treated effluent) and oil for minimizing the disposal of pollutants outside the industrial zone. Flexibility as well as complete independent operation of the treatment units have increased significantly the reliability of producing a final effluent of high and safe quality.