Landfill leachate treatment: a new approach

摘要

Municipal waste landfills generate leachates that must imperatively be treated before being discharged into the environment. The reverse osmosis membrane process is the most widely used method for treating these leachates. However, the efficiency of this process at the industrial scale is limited due to membrane fouling and the high osmotic pressures involved. This study develops a treatment which reduces these limitations. Chemical precipitation of the leachate using lime, followed by a standard filtration on a rotary drum vacuum precoat filter is studied. The osmotic pressure is decreased by 10 to 25% through precipitation of the carbonates, and foulants are eliminated by co-precipitation. The sludge is stable, chemically inert and relatively dry (50% siccity) and can be easily stored on site. Operating costs can be lowered by 50 % with decreasing the frequency of membrane cleanings and the concentrate volumes, which must be post-treated.