Filters and charcoal canisters remove trace odors, dust and volatile chemicals from leaks, spills and outgassing. A cabin heat exchanger in the lower deck cools the air and condenses the moisture, which collects in a slurper . Water from the slurper is moved with air to a fan separator , which uses centrifugal force to separate water from air. The air is recirculated and the water goes to a wastewater tank. Water Besides air, water is the most important quantity aboard the orbiter.
Water is made from liquid oxygen and hydrogen in the space shuttle's fuel cells .
The water from the fuel cells passes through a hydrogen separator to eliminate any trapped hydrogen gas. Excess hydrogen gas is dumped overboard. The water is then stored in four water storage tanks located in the lower deck. The water tanks are pressurized by nitrogen so that water can flow to the mid-deck for use by the crew. Excess water produced by the fuel cells gets routed to a wastewater tank and subsequently dumped overboard.