Sewer system

Wastewater purification

Every year, “Rīgas Ūdens” increases the sewer network’s pumping station capacity, in order to ensure safe wastewater collection and transport to the biological purification station at “Daugavgrīva.”

By the beginning of 2019, the City of Rīga’s sewer network was more than 1177 km (sewer collector and pipe diameter ranged from 150 mm to 2500 mm). The flow of household wastewater to the purification facilities is ensured by 67 pumping stations within the city territory.

At the “Daugavgrīva” purification station, wastewater is first purified mechanically (from sand and other debris) and then biologically using active sludge.  Biologically purified wastewater is channeled to the Gulf of Rīga – approximately 2.4 km from the coastline and at a depth of 15 meters. The residue (left over sludge) from the wastewater purification process is directed to sludge compression and is processed in methane collection containers to produce gas that is later utilized for heating.

When necessary, some “Rīgas Ūdens” customers that use the city’s sewer system have to carry out the initial purification of wastewater in their local purification facilities. The quality of this wastewater is periodically tested by “Rīgas Ūdens” water resource inspectorate and laboratory.

For renovation and control purposes, Rīga’s sewer system network has installed 25,000 manholes. The utility’s Sewer Network Department regularly performs preventative pipe maintenance and rinsing.

Every year, the quality of wastewater purification improves. After the reconstruction and modernization of the “Daugavgrīva” biological purification plant, Rīga will reduce the amount of nitrogen that ends up in the Baltic Sea by 500 tons per year.  Utilizing EU Cohesion fund financing, the wider expansion of the central sewer system is taking place in many of Rīga’s private residential housing districts. When this project is completed, more than 10,000 additional residents of Rīga will be able to take advantage of the convenience provided by the central sewer system.

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