Background Sludge is applied to agricultural land because of its agronomic properties. Although regulatory provisions and codes of practice aim to reduce related risks, there are concerns that this practice could result in heavy metals entering the human food chain and could negatively affect the quality of the water supply. Treatment for discharges from urban waste water treatment exist but they are often too expensive for small municipalities. Water used for the abstraction of drinking water shall be protected from eventual pollution. Short rotation coppices of willow (SRC) are a potential answer to these problems. Wastewater rich in nutrients such as nitrogen and phosphorous, and which has already been through lagoonage and wastewater treatment, can be applied to land used for willow coppicing, which is efficient for removing nutrients and other waste elements. Objectives The WILWATER project aimed to demonstrate the effectiveness in environmental and cost terms of short rotation coppices of willow (SRC) as a bio-filter for treatment of wastewater or safer utilization of sewage sludge and as a tool to limit accidental pollution close to lagoonage installations and drinking water collecting wells. The project further aimed to introduce SRC on a sufficiently large scale for evaluation of plantation, care and harvest operations, and to demonstrate positive environmental impacts, such as on flora, fauna and CO2 emissions. Results Short rotation coppices of willow were planted on 20 sites, equalling a total of 100 ha. Each site was evaluated and the impacts measured. Except for few sites, most of the expected environmental results were achieved: The purification capacity of the willow SRC: Nitrate and phosphorous were reduced to acceptable levels in accordance to European legislation on urban residual water. The willows completely absorbed the effluents as demonstrated by their absence from the drain installed on each site used for irrigation. The buffer zone for the drinking water preservation : The expected outcome in terms of water quality improvement were reached. The spread of wastewater treatment plant sludge: While this effect could not be measured over the short monitoring duration of the project, the beneficiary expects that an appropriate quantity of sludge spreading on willow SRC should reduce environmental impacts thanks to its perennial root system. Knowing the maximum intake by the willow should prevent over-fertilisation and reduce water pollution. The possibility of tertiary treatment of pollution: satisfactory results were achieved due to the high evapotranspiration capacities and perennial root system of willow SRC The use of willow SRC as biomass: A productivity of 8 to 12 t of dry matter per hectare a year can be reached, equalling approximately 40 MWh ha/year. The sustainability and continuation of the project’s outcomes is relatively assured. The willow site should remain unaltered, and the results will strengthen over time. The goal is to increase a network of willow SRC sites in Brittany in order to reduce the current running costs of the material. Other willow SRC initiatives are planned following the WILWATER model. The beneficiary is expected to be involved in the setting up of these sites. The project developed guides that are useful for the transfer of the project, and many private farmers, communities and industrials have already expressed an interest. However, implementing a willow SRC project will strongly depend on the sites, the possible synergy with other stakeholders with a complementary interest, the economic and political context. The willow SRC represents a vast amount of work and heavy investment. The WILWATER project points out the possibilities for optimisation of the system. Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section). This project has been selected as one of the 17 "Best" LIFE Environment projects in 2008-2009.