Landfilling is one of the most widely used forms of solid waste disposal, yet the management of landfill leachate is challenging because of the complex composition and high contaminant concentration. This study provides an on-site treatment system to treat 500 m3 day-1 of the leachate generated from the Perdido Landfill in Escambia County, Florida. The main concerns of the landfill leachate are ammonium-nitrogen, total dissolved solids (TDS) and biological oxygen demand (BOD) from the long-term monitoring (from September 1999 to May 2015). To target these major contaminants as well as other pollutants, we designed a wetland treatment system by fully utilizing the existing facilities at the Perdido Landfill site. The modified wetland treatment system consists of five components in series: leachate collection/aeration ponds, anaerobic ponds, aerobic ponds, wetlands and limestone filter ponds. The leachate collection/aeration ponds provide functions of nitrification as well as ammonia and CO2 stripping. The following anaerobic ponds focus on nitrogen removal by denitrification. The BOD is removed in the aerobic ponds. The TDS are removed in the wetlands and limestone filter ponds. In the wetlands, 60% of chloride and 40% of other contaminants are absorbed by Parthenium sp. In the limestone filter ponds, bicarbonate, calcium, magnesium and iron are removed.
Keywords: On-site treatment; TDS; landfill leachate; limestone; nitrogen; wetlands.