Disclosed is a method of cleaning sediment from the bottom of a large storage container of clean water comprising sanitizing a cleaning person and a suction pump to remove the majority of skin viruses, germs, bacteria and dirt from the surface of his skin and/or apparel and the suction pump; the cleaning person going underwater and slowly submerging; the cleaning person turning on the suction pump before reaching the bottom of the container; the cleaning person removing sediment from a spot on the bottom of the container before any part of his body disturbs the sediment; the cleaning person attaining footing in the clean spot; and the cleaning person removing the remainder of the sediment on the bottom of the container.
This process permits an inlet/outlet to be established in a liquid filled tank using an underwater diver without the necessity of draining or otherwise putting the tank out of service. The diver enters the tank at the top and places a dry pot against about the center of the back of the manhole cover. A hole is drilled in the manhole cover and a pipe nipple inserted through the hole. A flange is provided on the pipe nipple and if a gasket is not used, it is welded completely around to prevent leakage. A cap or valve is screwed onto the pipe nipple on the outside and the dry pot is removed. Various other ways of placing the pipe nipple through the wall are described. The installed nipple can be used by attaching a suction hose thereto for the purpose of removing sediments from the floor of the tank. If desired a smaller inlet/outlet installed in this manner is used to supply air for a diver working on the inside of the tank.