A support structure, such as a mattress, is provided for the placement and removal of a human waste container, such as a bedpan, with minimal exertion by the attendant and minimal movement of the person. The circuit comprises an led light source, a power controller and a power supply. The outlet pressure of the high-pressure-gas supply equipment is set to \u201c1critical pressure ratio\u201d or more times a filter inlet gas pressure so that the flow speed of the high-pressure gas ejected from the backwash nozzle is the speed of sound or higher.