Background The cleanliness of Europe's lakes and other bodies of fresh water is threatened by effluent discharges and excessive fertiliser usage. Currently, most domestic wastewater is treated using physical and/or biological processes to remove large particles (primary treatment) and decrease the oxygen demand on receiving waters (secondary treatment). Additional treatment to remove nitrogen and phosphorous from sewage effluent may be required under recent European Directives. This can be achieved by installing wastewater polishing systems (or tertiary treatment). However existing wastewater polishing systems can be costly to implement and operate, and produce sludge which must itself be disposed of. More cost effective, environmentally-friendly wastewater polishing solutions are therefore being sought by the water industry. Objectives The project aimed to: Demonstrate nutrient removal from sewage effluent using wastewater polishing and bioenergy crops; Enhance the efficiency of the system used in the project to ensure it can be widely adopted by water companies; Identify long-term environmental hazards from pathogens, heavy metals and hazardous organics by comparing the risks associated with their disposal in Water-Renew systems to their conventional disposal in surface waters. Results The Water-Renew project sought to further increase the body of knowledge regarding the use of sewage effluent for irrigation of short rotation coppices or plantations and has identified issues that should be considered prior to its implementation (effluent characteristics, crop type, soil and hydrology etc). Testing was carried out at five sites in the UK and Ireland under a range of conditions (both field and randomised trials), using a variety of different tree crops. Though Water-Renew faced serious problems from the outset which threatened the very viability of the project, including the loss of many project sites and the withdrawal of some of its co-financiers, the project team worked extremely hard to navigate through these issues, and by the end of the project, in December 2008, the beneficiary had managed to achieve all of its stated objectives. In particular, it succeeded in developing an operational model to determine the site specific design requirements of WaterRenew systems and to allow predictive estimates of treatment efficiencies. Generally, the project found there to be no lasting negative effects of establishing Water-Renew sites, and that there can be sizeable benefits from an increased yield of plantation forestry and coppices. However, the project did reveal considerable variability between sites (and the project ultimately used five sites instead of the three originally planned) and because of this, one of the project’s recommendations is that all aspects of any potential site should be analysed prior to commencing irrigation. At the end of the project the Environment Agency, the agency responsible in the UK, concluded that they were happy that the Water-Renew technology did not cause any major concern as a tertiary treatment of sewage effluent, but that any new sites would have to be considered on a case by case basis. The Environment Agency is also going to maintain one of the project sites at Godinton in Kent to continue to monitor the effects of the system. The project concluded that the WaterRenew technology is both cheap and effective, and produces a potentially useful by-product of fast growing crops to be used as fuel. Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).