Ltd. “Rīgas ūdens” has signed an agreement with the Central Finance and Contracting Agency (CFCA) on EUR 22.3 million co-financing from the European Regional Development Fund (ERDF) for the Biological Treatment Plant “Daugavgrīva” reconstruction and expansion project. The total investment amounts to EUR 64 million, aimed at improving the efficiency and quality of wastewater treatment facilities. Reconstruction and expansion works are scheduled for completion by the end of 2029. 

Ltd. “Rīgas ūdens” is the largest water utility company in Latvia which, in addition to water abstraction and supply, provides more than half of the country’s domestic sewage collection and wastewater treatment at the Biological Treatment Plant (BTP) “Daugavgrīva”, covering an area of over 50 hectares.

Within the project, two primary and four secondary sedimentation tanks at BTP “Daugavgrīva” will be renovated. The renovation of two primary and one secondary sedimentation tanks has already begun.

The project also provides for the expansion of the wastewater treatment complex, including the construction of an additional biological-process tank with two secondary sedimentation tanks and the implementation of a modified activated-sludge process; replacement of aeration systems and mixers in the existing biological tanks; installation of new air blowers; construction of a methanol micro-dosing system; reconstruction of the discharge pumping station; and introduction of a deammonification process for nitrogen removal from sludge water.

Krišjānis Krūmiņš, Chairman of the Board of Ltd. “Rīgas ūdens”: “As the largest water utility company in Latvia, we are fully aware of our responsibility toward the environment and residents. Every step we take is carefully planned and implemented responsibly, introducing sustainable solutions across all areas of our service development. The Biological Treatment Plant “Daugavgrīva” treats more than 51 million m³ of wastewater annually; therefore, this modernization is a strategically important step that will make a lasting contribution to both environmental protection and the improvement of residents’ quality of life. The ERDF co-financing confirms the significance and necessity of this project.”

The reconstruction and expansion of BTP “Daugavgrīva” will significantly enhance the efficiency of wastewater collection and treatment services, ensuring the effective operation of infrastructure, reducing anthropogenic pollution, and improving the quality and performance of wastewater treatment for more than 600 000 residents in Riga and its metropolitan area. At the same time, this large-scale project will contribute to the fulfilment of European Union directive requirements in Latvia’s water-management sector.

The total eligible project costs amount to EUR 63 819 983.09, including EUR 22 309 636.00 of ERDF financing. The remaining costs will be covered by borrowed funds and the company’s own resources. The project is expected to be completed by the end of 2029.

The Biological Treatment Plant “Daugavgrīva” is located in the north-western part of Riga, on Buļļu Island, Dzintara Street, with a total area of 52 hectares, approximately 30 percent of which remains undeveloped.

The plant was commissioned in 1991, built according to a 1983 design to ensure primary and secondary wastewater treatment. In 1999, reconstruction works were carried out to replace the aeration system, reorganize the process-tank layout, and build a new screening facility and grit traps. The most recent upgrades were completed in 2014, when the biological treatment process was rebuilt to improve tertiary treatment, achieving a design capacity of 200 000 m³ per day.

In parallel, another significant infrastructure project will be implemented within the BTP “Daugavgrīva” area – the expansion of the existing digester park, involving the construction of two new digesters and the necessary auxiliary systems. This is one of the largest and most technically complex water-management projects in Latvia in recent years, aimed at substantially increasing sludge-treatment capacity and advancing the company’s progress toward energy neutrality. The project will include two new digesters with a total volume of 12 000 m³, ensuring complete anaerobic sludge treatment and a major increase in biogas production. Upon completion, BTP “Daugavgrīva” will achieve up to 85 percent energy neutrality, thereby improving environmental quality and contributing to the city’s sustainability.