Bridgeton Landfill is a large, closed landfill near St Louis, Mo close to the Missouri river where leachate was permitted to be discharged to the public sewer without biological treatment. High levels of methane and hydrogen sulfide had been measured in the public sewer. A methane and hydrogen sulfide stripping plant was designed to remove dissolved methane and hydrogen sulfide in solution before the leachate was discharged to sewer.
Leachate is the liquor that is collected at the base of landfills after rainwater has entered the emplaced waste materials and leached out contaminants at the bottom of the landfill. Depending on the nature and age of the wastes, the characteristics of the leachate will change. There are currently 6 leachate pumps capable of pumping 175 gpm for a total of 1050 gpm. One to six pumps operate at one time to maintain a leachate depth of 30’ in the landfill. An average leachate flow of 127,000 gallons per day has been observed.
A system was designed to remove the methane and hydrogen sulfide that is in the leachate solution. Cady Aquastore installed a primary 25’ diameter by 29’ tall Aquastore tank. This tank was then outfitted with a centrifugal pump and a spray atomizer nozzle. The typical operation mode 24 hours 7 days a week is with the pump running, and leachate is drawn from the bottom of the tank about 10” off the floor and forced though a 2” VeeJet spray nozzle. The nozzle will atomize the leachate 24” above the liquid level in a 50 degree wide horizontal spray pattern. It has been observed that the spray hits the top of the liquid approximately 2/3 of the way across the tank.
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