A method and valve apparatus for collection of fecal matter designed to operate efficiently in a zero gravity environment is presented. The system comprises a waste collection area within a body having a seat opening. Low pressure within the waste collection area directs fecal matter away from the user's buttocks and prevents the escape of undersirable gases. The user actuates a piston covered with an absorbent pad that sweeps through the waste collection area to collect the fecal matter, scrub the waste collection area, press the waste against an end of the waste collection area and retracts, leaving the used pad. Multiple pads are provided on the piston to accommodate multiple uses of the system. Also a valve allows air to be drawn through the body, so the valve will not be plugged with fecal matter. A sheet feeder feeds fresh sheets of absorbent pads to a face of the piston with each actuation