Background Eutrophication is a major issue throughout the European Union. It is caused by high loads of nutrients, mainly phosphate and nitrogen, being discharged to water. It results in reductions of biodiversity, and a decline in the ecological quality of surface waters. Furthermore, it can lead to blooms of toxic algae. Over the years, the phosphate load has decreased, but nitrogen concentrations remain high. Nitrogen mainly derives from agricultural sources, but is also present in the effluent from wastewater treatment plants. Current nitrogen-removal technologies are characterised by high costs and unfavourable environmental footprints, require energy-intensive aeration and are space intensive. The development and implementation of cost-effective measures to improve the ecological quality of surface waters are central to EU and national policies. CENIRELTA (Cost-Effective NItrogen REmoval from wastewater by Low-Temperature Anammox) is an effective nitrogen-removal technique, with low investment costs and the possibility of generating revenues. Objectives The CENIRELTA technique is based on anaerobic treatment of waste water with anammox (ANaerobic AMMonium OXidation) bacteria. The anammox process is proven at elevated temperatures (30-35oC) and high nitrogen loads. CENIRELTA, however, has refined the technique so that it works at low temperatures and low nitrogen concentrations in wastewater. First estimates of repeat potential indicate that more than 1 000 waste water treatment plants in the EU could benefit from implementation of the technique. Additional gains are possible at sites where treatment is not yet implemented, particularly in southern and eastern EU countries. The CENIRELTA project will demonstrate the technology through a pilot installation on a scale large enough to extrapolate to full scale. The pilot site will be WSHD's Dokhaven wastewater treatment plant. The project will: Provide sound evidence of the effectiveness of CENIRELTA, through monitoring and economic analysis; Combine all relevant process control information into a steering model, facilitating rapid implementation at full scale; and Disseminate the results of the demonstration project to stakeholders in the EU. Expected results: This pilot project will demonstrate that CENIRELTA offers a vast improvement in effectiveness, cost-effectiveness and sustainability over other methods for nitrogen removal in wastewater treatment plants. The technique will offer: Removal efficiency above 85%; Energy use reductions of 50-60%; and Sludge yield increases of at least 20%, enhancing biogas production.CENIRELTA will also provide a comprehensive set of evidence on the attractiveness of the technique for full-scale application, including a process-control model, which will facilitate rapid implementation.