Petroleum refinery wastewater treatment using a polysulfone-nano TiO2 hybrid membrane coupled with an ozonation process as a pre-treatment

Abstract

Fouling has been the main problem that seriously hinders membrane applications for petroleum wastewater treatment. This study aimed to explore advanced membrane process integrated with ozonation as a preliminary treatment. Ozone utilization was set at a constant dose of 3000 mg/h for different ozonation times and temperatures. A longer ozonation time significantly improved the removal of pollutants. Ozonation at 30°C for 120 min removed up to 38.25% total dissolved solids (TDS), 73.33% organic compounds expressed as chemical oxygen demand (COD), 11.6% ammonia, and 62.15% total phenol. Although an increase in the ozonation temperature increased ammonia removal by up to a remarkable 82%, it did not significantly affect the TDS, COD, and phenol removal efficiencies. Scanning electron microscope (SEM) and Fourier-transform infrared (FTIR) evaluations of the fouled membrane revealed that membrane fouling was caused by organic compounds consisting of hydrocarbon oil, benzene, toluene, xylene, phenol, and salt. Ozonation enhanced the permeate flux of the membrane by up to 96% and improved pollutant removal by up to 77%. The ozonation process was also responsible for the reduction of fouling resistance on the membrane surface by up to 21%.