THE USE OF EXTENDED AERATION AND IN-SERIES SURFACE-FLOW WETLANDS FOR LANDFILL LEACHATE TREATMENT

Recently in the USA, the Solid Waste industry has undergone specific c hanges in landfill regulations. The Federal Resource Conservation and Recovery Acts (RCRA); and EPA subtitle D regulations, as well as strin gent State regulations, impose minimum criteria for municipal solid wa ste facilities in the areas of location, operation, groundwater monito ring, and leachate management. In conjunction with these State and Fed eral mandates the University of West Florida developed a leachate trea tment technique utilizing extended aeration and surface-flow construct ed wetlands. Sampling of water quality has occurred monthly since Febr uary 1992. Parameters examined include: Nitrogen (NH3,), Total Suspend ed Solids (TSS), Total Phosphate (TPO4), Total Organic Carbon (TOC), p H, Alkalinity, and Chlorides. Chemical Oxygen Demand (GOD), Total and Fecal Coliforms, Priority Pollutant Metals, and limited organic analyt es are sampled on a less frequent basis. Samples are collected at a ra w leachate site (L(0)), primary aerated lagoon (L(1)), and 6 stations within the 1.1 hectare constructed wetland complex (S-1; W-1; W-3; W-5 ; W-7; W-9) and one sandfilter (SF) location. Results thus far indicat e removal percentages of the tested analytes average between 64% and 9 9%. This data suggests various physical, microbiological and chemical processes occurring within the aerated lagoon and constructed wetlands can provide an effective alternative to standard techniques for landf ill leachate treatment and disposal. The methods as described have pro ven to be ideal for the circumstances occurring at the Perdido Landfil l.