The influence of process conditions during membrane filtration of oily water

The performance of six membranes were compared using a stable 500 parts per million (ppm) synthetic emulsion generated using a mixture of lube oil and heavy fuel oil from a Chinese power plant. Six membranes were tested, five inorganic and one organic; pore sizes varied between 0.2 mu m and 0.005 mu m. Each membrane underwent extensive tests where the effects of Reynolds number, transmembrane pressure and temperature were investigated. Final permeate fluxes varied between 0.05 - 0.32 m(3)/hr.m(2). These results were compared to a series of field tests on a ship, where bilge water from a sludge separator was used. Permeate samples were analysed for total oil and grease using a gravimetric method. All membranes proved capable of reducing oil in water concentration to below 15 ppm.