News and articles

Cleaning the Baltic Sea by improving the treatment of wastewater

By far the most nutrients that enter the Baltic Sea are the result of diffuse loading from agriculture. According to an estimate by HELCOM, the Baltic Marine Environment Protection Commission, the fastest way to help the sea is nevertheless to focus on the remaining large point sources of loading. This is especially true for reducing phosphorous, the key nutrient for blue-green algae and a main nutrient behind the eutrophication of the Baltic Sea. It is estimated that up to two-thirds of the cuts in phosphorous loading required to restore the Baltic Sea by 2021, can be achieved by further improving the treatment of municipal wastewater and removing the phosphorous from toilet water.

The John Nurminen Foundation began promoting a cleaner Baltic Sea in 2004 in St. Petersburg and now operates throughout the Baltic Sea Region. The foundation’s motto is to select targets where the least cost achieves the largest possible positive impact on the environment. Cooperation with local water utilities can begin if they have a functional wastewater treatment infrastructure – as well as the motivation and readiness to cooperate.

St. Petersburg is a model pupil

The foundation’s cooperation project with the St. Petersburg water utility was completed in 2011. Improved wastewater treatment combined with cuts in phosphorous emissions from the fertiliser plant in Kingisepp have reduced the phosphorous loading on the Gulf of Finland by almost 60 percent. The City of St. Petersburg has indeed become a model pupil in wastewater treatment, but there remains a lot to do still in the Leningrad and Kaliningrad regions of Russia. Wastewater sludge could also be utilised more as an energy source. The sludge is already being recycled in Viikinmäki in Helsinki and Warsaw. According to Leszek Drogosz, Director of the Infrastructure Department at the City of Warsaw, 30 percent of the energy required annually to light up the city’s streetlamps is created by utilising the biogas from wastewater sludge. This corresponds to 140 railway wagons of coal a year.

Finnish wastewater treatment plants produce cleaner water for the Baltic Sea

Timo Salonen from Algol Chemicals is an expert in wastewater treatment chemicals. The chemicals he supplies to municipal wastewater treatment plants for removing phosphorous include polyaluminium chloride (PAX) and ferric precipitation (PIX) products. “The quality of municipal wastewater treatment in Finland is very good, I would say. In practice, the water released into the sea from wastewater treatment plants along the coast is much cleaner than the seawater itself. We achieve good results especially in eliminating phosphorous loads,” Salonen says.

This article is based on material supplied by the John Nurminen Foundation and an interview with Timo Salonen, product manager at Algol Chemicals. The Algol Group supports the Clean Baltic Sea project

Further information about wastewater treatment chemicals