Background The EU Water Framework Directive (WFD) provides guidelines for the protection of surface water, coastal water and groundwater and will be mandatory from the year 2015. For the sustainable management of groundwater and surface water, the WFD has identified priority substances, which are considered hazardous enough to necessitate a systematic reduction of their levels. A national screening of effluent of Waste Water Treatment Plants (WWTPs) in the Netherlands has shown that WWTP-effluent forms a significant emission source of priority substances into surface waters. To achieve the discharge limits for these substances before 2015, additional treatment steps are required. Objectives Current techniques for the treatment of municipal wastewater are not designed to remove the priority substances mentioned in the WFD, which are to be met in 2015 (plans with the measures required for achieving these standards must be ready by 2009). The objectives of the LIFE project were to prepare the development of these measures by demonstrating the technical feasibility of: The removal of dissolved organic compounds using coagulants in WWTP-effluent; The simultaneous removal from WWTP-effluent of nitrate and phosphate in a filter bed; The use of activated carbon in granular (GAC) or powdered (PAC) form in WWTP-effluent. GAC is applied in the form of a filter bed. PAC is dosed in line and subsequently filtered from the effluent; The application of advanced oxidation on municipal WWTP-effluent; and Bio filtration at extremely low substrate-concentrations. Results The WET project was successful in demonstrating the technical feasibility of a number of innovative waste water treatment processes to achieve the standards for effluent set in the WFD by 2015. The main project results are summarised as follows: Removal of phosphate by metal salt dosing and nitrate removal using a carbon source supported dentrification process can be combined in a one filter configuration, resulting in a structural achievement of the WFD standards for Ptotal ( The use of Advanced Oxidation Processes resulted in a reduction of medical remnants and pesticides by at least more than 70 % and in a desinfection level up to the hygienic limits set for in the EU Bathing Water Directive (76/160/EEC). Removal of heavy metals and of organic micro-pollutants and suspended solids achieved by using the same combination of techniques. In general the project provided insight in the measres that need to be adopted in order to achieve the quality standards included in the Water Framework Directive for WWTP effluent. The WFD values for nitrate and phosphate can be achieved with the installation - even with the single filter set-up, which has lead to considerably lower costs than the set-up with separate filters for N and P removal. The removal of other priority substances of the WFD has been investigated in the second monitoring phase of the project, in which Advanced Oxidation Processes (using ozone, hydrogen peroxide and uv-light) were tested. Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).