Eutrophication is a major problem in the Baltic Sea. Its caused by excessive phosphorus and nitrogen loads coming from land-based sources. At least 95% of the phosphorus load enter the Baltic Sea waterborne and a major part of this load originates from point sources. Here the municipal waste water treatment plants (WWTPs) play the primary role. New actions to reduce the amount of phosphorus from the effluent ending up to the Baltic Sea are immediately needed: according to HELCOM, failure to react now would undermine both the prospects for the future recovery of the sea and its capability to react to the projected stress by the climate change. Besides, inaction will affect vital resources for the future economic prosperity of the whole region and would cost tenfold more than the cost of action. In order to achieve clear water, which is one of the main objectives of the HELCOM Baltic Sea Action Plan, phosphorus inputs to the Baltic Sea must be further cut by about 42% (15 000 tons). Cost effective techniques to remove phosphorus from wastewaters are in use e.g. in the Nordic countries. Current bottlenecks that hinder the Baltic Sea Region (BSR) wide implementation of these techniques are: 1) lack of good examples and knowledge at plant level 2) lack of funding 3) lack of common commitment and joint implementation. PURE prepares and implements investments that reduce phosphorus emissions from the Baltic Sea. The project targets selected municipalities and their waste water treatment plants and supports them to reach a phosphorus content of 0,5 mg/liter in outgoing wastewaters. This level is in harmony with the HELCOM recommendation and is half of the concentration stipulated by EU Waste Water Treatment Directive. Altogether PURE aims at annual reduction of at least 300-500 tons of eutrophying phosphorus from the Baltic Sea. As phosphorus removal slightly increases amount of sludge in WWTPs, PURE also presents and develops sustainable ways to handle this sludge. Project implements the HELCOM Baltic Sea Action Plans Eutrophication Segment and its Recommendation 28E/5 on more stringent requirements for phosphorus removal from municipal WWTPs. PURE would also implement EU Baltic Sea strategy as its draft action plan addresses a flag ship project "Clean waste water". PURE demonstrates low-cost, high-impact actions that result in measurable outcome regarding phosphorus discharges to the Baltic Sea. Project demonstrates potentials of joint implementation and joint investments in the BSR in combating the eutrophication in a cost-effective way. Project results and methods will be compiled into a book of good practices in chemical phosphorus removal and sustainable sludge handling at municipal WWTPs. Project partners include Union of the Baltic Cities Commission on Environment (UBC EnvCom) as lead partner, John Nurminen Foundation (JNF), HELCOM, Riga Water, Brest Vodokanal, Luebeck and several other central locations around the BSR Achievements: Technical audits in five wastewater treatment plants (Brest, Gdansk, Jurmala, Kohtla-Järve and Szczecin) were done by consultant together with the project partners. Audits contain suggestions for each audited plant on how to develop treatment processes and to reach 0.5 mg phosphorus/l in outgoing water. The audit reports are available on the PURE website also for use of other water companies. Equipment and processes on several sewage treatment plants on the Baltic Sea watershed have been permanently improved. Investment plans were prepared, public procurements for purchasing the equipment done; deliveries, installations and putting into operation at the partner treatment plants were accomplished. Investments for phosphorus removal included flow meters, precipitant dosing container and sludge dewatering centrifuge in Riga. Investment in Jurmala consisted of adjustments of biological treatment basin walls, flow meters and pressure sensor and a polymer unit. The investment in Brest included construction works of the chemical storing and dosing station, and the equipment for chemical dosing and laboratory analyses. Three PURE partner treatment plants were deleted from the HELCOM hot spots list of the worst polluters of the Baltic Sea: Kohtla-Järve (Estonia), and the two treatment plants in Szczecin (Poland). PURE Benchmark online database (www.purebenchmark.net) was created. The purpose of the tool is to gather descriptive information of the technology used in waste water treatment plants and nutrient inputs from municipalities in the Baltic Sea region. The basis is on local level activity; municipalities and their wastewater treatment plants have an access to their own data, and can update it. Sustainable sewage sludge management was one of the ongoing topics. HELCOM started the work for updating its municipal sewage recommendations to include sustainable sludge management in the scope, using the comprehensive PURE sludge publication as a background material. There has been a lot of discussion on different international, national and local fora of the importance of efficient municipal sewage treatment for combating eutrophication. From the Baltic Cities Summit in connection with the HELCOM Ministerial Meeting, to different EU Strategy for the Baltic Sea Region events, articles on public media to the Final Conference of PURE, the local level achievements and challenges in reducing nutrient loading have been on the agenda. Brochures, e.g. Our Common Challenge – Eutrophication were published. Electronic Newsletters were distributed among important stakeholders like water companies and municipalities and their networks, national and EU authorities and international financial institutions. Themes for the newsletters were sewage loading data issues, sustainable sludge management and presenting the investments of the project. All the published materials are available on the PURE website.