Efficiency control of landfill leachate irrigation on energy crops

Abstract

Leachate constitutes the major long-term em1ss1on from landfills. A possible treatmentmethod is collection and subsequent irrigation on short rotation coppice during the growingseason, for example onto willow stands (salix). Theoretically, irrigation allows both a volumereduction and a reduction of potentially hazardous leachate contents, such as nitrogen, organiccarbon and heavy metals. In this work, both hydraulic and reductive efficacy of leachateirrigation at the municipal solid waste landfill Ronneholm, in Southern Sweden, have beeninvestigated by means of a water and a mass balance. For the latter, the emission values ofcopper, chromium, nickel, zinc and total nitrogen were used, This study covers the periodfrom November 2002 until December 2003. The water balance and the mass balance weremodelled with a straight-forward box-model. The results suggest the importance of favourableirrigation schemes and the importance of sedimentation for leachate heavy metal reduction.Water balance calculations pinpointed potential for improving the efficiency of the leachatevolume reduction. In addition, the susceptibility of emission values for short term water levelchanges was checked by daily sampling during a week, at a across section of the landfill.Initial results suggest that measured heavy metal concentrations fluctuate with water levels inthe landfill body. This might be utilised to optimise irrigation schemes. A simple water andmass balance model has proved to be an effective method to both control leachate treatmentand to serve as a starting point to develop leachate reduction schemes.