A water treatment plant effluent is to be disinfected with chlorine from ton cylinders of compressed gas. The plant is 5 million gallons per day. There are a total of 10 useable cylinders in the plant. if the water is chlorinated with a dose of 2 milligrams per liter, how long will the cylinders last until empty? if the gas were to be replaced with liquid sodium hypochlorite (bleach), how many gallons would be required to last the same time as the gas? The sodium hypochlorite solution strength is 15 percent by weight and has the same unit weight as water (specific gravity 1.0). One pound of sodium hypochlorite has the same disinfecting strength as one pound of chlorine gas.