MSW leachate irrigation in landfills has been in widespread use since the 1970s for a range of purposes that include leachate management, enhanced landfill gas generation allowing increased recovery and to improve the sustainability of landfills. Resource managers are challenged with disposal of the leachate produced from its degradation, and leachate irrigation is no different is no magic panacea. It can provide a low cost solution to leachate treatment and disposal, for at least part of a landfill’s life. However, leachate recirculation also has the potential to cause problems such as surface breakouts, elevated leachate levels, and reduced landfill stability, and must be only used with great care.
Landfill Leachate Irrigation into Willow Coppice
Landfill leachates usually need to be treated before discharged. and using soil-plant systems for this has gained substantial interest in Sweden and in the UK The soil-plant system most used for landfill leachate irrigation is that of short-rotation willow coppicing with Salix. Willow plants did not react negatively to very high annual loads of nitrogen (<= 2160 kg N/ha), chloride (<= 8600 kg Cl/ha) and other elements.
Mean annual growth can be high and in one Swedish Study was 15. 98 and 12.6 tonnes DM/ha during years 1-3 For one of two willow varieties tested. However, irrigation with leachate resulted in elevated groundwater concentrations of all elements applied. The study team reported that treatment efficiency varied considerably for different elements, but was adequate when moderate loads were applied.
Landfill Leachate Irrigation into Poplar Trees
Short-rotation tree forests are irrigated with landfill leachate to reduce both leachate volume and nutrient content. As we have alerady stated, it is of interest both for leachate treatment and energy recovery, to optimize the productivity of such plantations, and one such potential advance may lie in the use of poplar trees.
Poplar (Populus species) trees provide an opportunity for ecological leachate disposal as an irrigation source for managed tree systems. Information about sodium (Na+), chloride (Cl -), and nutrient uptake and distribution into tissues of Populus genotypes irrigated with landfill leachate is needed to maximize biomass production and to understand impacts of leachate chemistry on tree health. Unfortunately, data on the response of poplar genotypes to landfill leachate irrigation is sparse so it is hard to make a case for leachate irrigation treatment schemes using poplar trees.
Municipal solid waste landfill leachate must be removed and treated to maintain landfill cover integrity and to prevent contamination of surface and ground waters. Leachate irrigation has been reported to increased plant biomass but not to significantly affect soil metal concentrations. At the same time plant metal concentrations remained within normal ranges. Rotating spray areas and timing irrigation to follow seasonal capacities within the system for evapotranspiration, will reduce the localized impacts of leachate application. However, careful monitoring of undiluted leachate applications is required to avoid negative impacts on vegetation or soils, and over-time elevated solute leaching losses.
The irrigation of Salix species with landfill leachate, when grown on landfill sites, is a financially attractive solution to leachate treatment and landfill site remediation. The irrigated treatment in the above study showed elevated concentrations of soil nitrate, ammonium, and chloride relative to the water only irrigation treatment, but provided such issues can be resolved with the regulator leachate irrigation can be a great low cost solution to landfill leachate treatment.
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Related terms: Landfill Leachate Treatment, Landfill Leachate Collection, Landfill Leachate Definition, Landfill Leachate Recirculation, Landfill Leachate Characteristics, Leachate From Landfills May Include, Leachate Health Facts, Composition of Landfill Leachate