Where does wastewater go?

​​​​​​​Citizens and businesses of the Helsinki Metropolitan Area produce around a hundred million cubic metres of wastewater annually. The wastewater travels through the sewer network to be treated at our wastewater treatment plants. The wastewater treatment process requires mechanical, chemical and biological methods that remove garbage and most of the organic matter, nitrogen and phosphor from the wastewater. 

In order to protect the shallow coast of the Baltic Sea and to preserve its recreational value, the treated wastewater is conducted into the open sea in front of Helsinki and Espoo.

The Helsinki Metropolitan Area has two wastewater treatment plants, one in Viikinmäki, Helsinki, and the other in Suomenoja, Espoo. In these plants, we process the wastewaters of more than one million people as well as industrial wastewater.

​We are currently building a new wastewater treatment plant in Blominmäki, Espoo, and it should be completed in 2020. The Blominmäki wastewater treatment plant will replace the current Suomenoja wastewater treatment plant.​​