A sump pump control includes a microprocessor that sends a trigger pulse to an alternistor to turn the alternistor on and connect the sump pump to an NC power source. The outer shell may be formed from a non-high impact resistant material, such as a thin metal or a composite material. An inlet valve is movable to open and close an intake port of a combustion chamber. The propylene concentration of the permeate in the membrane is then reduced with a sweeping gas.