Biomass Production and Nutrient Removal from Municipal Wastes Using Willow Vegetation Filters

Short rotation forests, consisting of various willows (Salix spp.), are suitable vegetation filters with regard to removal of nutrients from municipal sewage sludge, wastewater, leakage water and bioash (wood ash). As long as contents of heavy metals and known organic compounds are kept below accepted limit values, such waste oducts can be regarded as valuable nutrient resources, and particularly when the vegetation is produced for energy purposes instead of for direct or indirect human consumption. The benefit is three-fold: (i) purification of municipal waste using natural circulation, (ii) production of biomass for energy purposes, (iii) reduction of air pollution when burning wood instead of fossil fuels. Most Salix plantations can be used as recipients of sludge and ash as well as be irrigated with wastewater from sewage plants or with leakage water from dumps. Regarding waste and leakage water irrigation, a combined artificial wetland for winter conditions and a willow vegetation filter during the g...