Concentrating emulsified oily wastewater by integrated membrane technology

The effects of operating pressure, feed temperature, oil content of feed solution, and membrane surface flow rate on membrane flux, con-centration multiple, and average particle size of oil droplets in the concentrated solution during the single-stage membrane concentration process were investigated. The experimental results show that within a certain range of operating conditions, the membrane flux increases with the increase of operating pressure, feed temperature, and membrane surface flow rate, and decreases with the increase of the oil con -tent of the feed liquid, the concentration ratio, and the average particle size of oil droplets in the concentrated solution to determine the optimal conditions for single-stage concentration. Then, on the basis of single-stage membrane concentration conditions, three different pore size separation membranes are combined in different ways. After concentration through multi-stage membranes, the particle size of the oil droplets in the concentrate is greater than 20 lim, which is beyond the particle size range of the emulsified oil, and the concentration of the oil in the concentrate is 20-30 times that of the original oil. The method can realize the recovery of oil resources in the emulsified oil-containing wastewater.