Bore a hole at the bottom of a large container, using a drill with the same diameter as the pipe that will lead the water away from it. Affix a pipe in the hole using a wrench and some connectors and mark this container as "1." Attach a tap on the pipe leading away from the container.
Connect the pipe from the tap to the inlet of the pump. Connecting this should be simple with the use of a wrench, since the pump only has two pipe slots, the input and the output, that are already threaded. You may have to use a connector to join the pipe to the slot. Connect the pump to its power source, but don't turn it on just yet.
Connect another pipe from the output of the pump, the same way you did the input pipe, to another container and mark it as "2." Fix the semipermeable membrane immediately at the entrance of the pipe to the container using an adhesive, making sure it is sealed all around. Create a junction just before the pipe opening to the container by cutting the pipe at this position. Thread the cut edges using the die then connect a T-junction pipe. Attach another pipe of a smaller diameter to the junction and lead it to another separate container and mark it as "3."
Pour the oil and water mixture into container 1 and open the tap. Turn on the pump to build pressure in the system. The pressure is supposed to force the liquid mixture against the membrane, and only water will pass through and end up in container 2. The remaining oil will pass through the junction and end up in container 3. Container 2 will contain pure water while 3 will contain oil with traces of water.