Helsinki Metropolitan Area wastewater treatment plants reach record high – nutrient load into the Baltic Sea lowest ever

Photo: HSY/ Tuomas Uusheimo. The wastewater treatment plants in the Helsinki Metropolitan Area achieved record-breaking purification results in 2025. At the same time, the nutrient load in the Baltic Sea fell to a historically low level.

Metropolitan area wastewater treatment plants achieved the best cleaning result ever in 2025. According to the Helsinki Region Environmental Services (HSY), nutrient loading into the Baltic Sea has fallen to a historically low level.

The improvement in results has been influenced by the investments made by HSY.

“The treatment result particularly reflected the optimization of the Blominmäki treatment plant, which improved the results compared to the previous year,” says HSY’s Tommy Fred.

According to HSY, the operational reliability of water supply was also significantly strengthened. A record 71,7 million euros were invested in network renovations in 2025, and a total of 134 kilometers of the network were built and renovated.

Text: Uusiuutisten editorial team

Photo: HSY/ Tuomas Uusheimo. The wastewater treatment plants in the Helsinki Metropolitan Area achieved record-breaking purification results in 2025. At the same time, the nutrient load in the Baltic Sea fell to a historically low level.

More on the topic

Excavation of the Blominmäki wastewater treatment plant will begin in September
30.7.2015 The excavation of the cavern for the HSY wastewater treatment plant to be built in Blominmäki, Espoo, will begin in mid-September. In June, the board of the municipal association selected the contractor for the excavation of the bedrock of the Blominmäki wastewater treatment plant…
Green deal for wastewater treatment
The ninth voluntary green deal agreement related to environmental goals has been signed in Finland. The Ministry of the Environment, the Finnish Waterworks Association and the Association of Local and Regional Authorities have signed an agreement on the treatment of municipal wastewater. The agreement…
Inorganic nitrogen fertilizer from wastewater
15.9.2016 How to product inorganic nitrogen fertilizers from sewage sludge and wastewater? Gasum's KiertoTyppi project has found ways to do this. The goal is that recycled nitrogen products could be used…
Recycled nutrients recovered from wastewater as effective as synthetic fertilizers – NPHarvest believes the circular economy will boost Europe's self-sufficiency
Nitrogen and phosphorus captured using a membrane method developed by NPHarvest produced results in cultivation experiments that were just as good as industrially produced nutrients. The Helsinki-based startup announced…
Recycling wastewater nutrients with algae
The recovery of nitrogen and phosphorus contained in wastewater using microalgae could enhance recycling and improve the condition of water bodies. From a long-term development perspective, phosphorus…
Go on a wastewater journey on Baltic Sea Day!
What happens to dentures that fall into the toilet? What is the tortuous journey of our waste? Is wastewater good for nothing anymore? On Baltic Sea Day, you can jump into the toilet yourself and…
Pine bark cleans antibiotics and drug residues from wastewater – University of Oulu came up with the idea of utilizing an inexpensive side stream from the forest industry to remove harmful substances
The purification column looks like a large coffee filter. However, instead of coffee grounds, the water passes through a purification material made from pine bark, and the water is not clean either, but contains traces of medicine and…
A solution to a problem that has plagued us for over 20 years – sustainably recovering valuable metals from industrial wastewater
Jyväskylä University of Applied Sciences' business accelerator BioPaavo's DinexHackathon resulted in the discovery of several alternative solutions, technologies and business partners for the recovery and…
The Ravita method effectively utilizes phosphorus and carbon from wastewater
New treatment methods developed by HSY (Helsinki Region Environmental Services) enable the efficient recovery and utilization of nutrients and carbon from wastewater, also on a large scale. The issue…
Materials for recycling – but how?
The circular economy is changing business and revenue models. In a circular economy, consumption is based on the co-ownership, rental and lending of services and materials rather than ownership. An essential part of the circular economy…
Neste strengthens its research expertise – establishes innovation center in Singapore
Neste has opened a new innovation center in Singapore. The center aims to strengthen its research and development capabilities globally. Asia has become an important market for Neste.…
Clean-up efforts celebrate anniversary – How many garbage bags do Finns collect?
YLE has launched the One Million Garbage Bags campaign, in which every Finn can participate on their own route, in nearby areas, on the roadsides of their home municipality or in any environment.…