Willow short-rotation coppice for treatment of polluted groundwater

Willows are a highly versatile tree species that may have multiple environmental applications, including bioenergy, green structures, etc. Here we report the results of a field trial that used willow short rotation coppice stands to improve the quality of groundwater polluted mainly with ammonia nitrogen (NH4-N), which is potentially life-threatening to many aquatic organisms. For a two-year period, 5200 m3 ha−1 of NH4-N polluted groundwater were treated with very little environmental risk and high decontamination efficiency, mainly due to the high evapotranspiration rates and nutrient retention, and fast growth of the willow used. We estimated that the willows demonstrated an overall efficiency level of 95% in reducing NH4-N concentration in the leachate. The resulting high aboveground biomass yield, which can be used for other environmental applications (e.g. bioenergy), enhanced the overall value of this phytotechnology.