ABSTRACT
The need for efficient collection and treatment of leachate from solid waste landfills to avoid surface-water and groundwater contamination is widely recognized. A method of on-site treatment is needed that is inexpensive and requires little maintenance or power after landfill closure. The design and operating limits for treatment of landfill leachate in the humid temperate zone, however, are not well documented. Hydraulic conductivity of substrate materials was measured in July 1989 (before leachate was applied) and again at the end of the study. The initial values at the start of leachate application (July 1990) were assumed to be equal to the pretest values measured in July 1989. Constructed wetlands may provide a treatment system for municipal solid waste landfill leachate that decreases contaminant concentrations and total leachate volume and requires little maintenance, management, or energy. The 2-year old plants had no effect on the steady decrease in hydraulic conductivity, nor on the concentrations of most leachate constituents.
