Application of a polytetrafluoroethylene (PTFE) flat membrane for the treatment of pre-treated ASP flooding produced water in a Daqing oilfield

Abstract

ASP (alkaline/surfactant/polymer) flooding oilfield wastewater, which is commonly produced in oil extraction processes, contains high organic content, and waste crude oil, water resources and sewage need to be treated prior to re-injection. In this study, pre-treated ASP flooding oilfield water produced in Daqing, China was treated by a PTFE microfiltration membrane and the removal efficiency of the main pollutants in the oilfield-produced water was studied. The content of oil and suspended solids (SS) in the permeate obtained with the membranes was 1.15 mg L⁻¹ and 1.61 mg L⁻¹, respectively, which met the re-injected water quality standards in China. A microscopic analysis of fouling showed that the membrane pollutants were mainly composed of petroleum organic pollutants, and a small amount of SiO₂, CaCO₃, MgCO₃ and other inorganic pollutants was observed. Accordingly the operating conditions of operating flux, back-washing cycle, back-washing flux and gas-washing flux were investigated to decrease membrane fouling.