Visit to Viikinmäki wastewater treatment plant

Photo: Tina NyforsStaff from CITYWATER and the Baltic Sea Challenge visited the Viikinmäki wastewater treatment plant (WWTP) in Helsinki. The purpose of the visit was to learn about wastewater treatment and to gather knowledge for the cost-benefit analysis that will be conducted by the City of Helsinki.For CITYWATER who works with storm waters, it was Interesting to hear about the relationship between stormwaters and overflood management from the water utilities point of view.

The Viikinmäki WWTP is a Baltic Sea Challenge partner and is the  largest WWTP in the Nordic countries. It handles waste water from 800 000 inhabitants and from industry. The treatment results are of internationally high level: 95 per cent of the phosphorus and about 90 per cent of the nitrogen can be removed from wastewater.

The treatment is conducted by means of a mechanical and biochemical processes that produces sludge and biogas as by-products. The sludge is composted and used in landscaping, and the gas is utilised as an energy source. The treated wastewater is led through a tunnel into the sea.

In the study visit participated Jari-Pekka Pääkkönen, leading environmental research at the City of Helsinki Environment Centre; Miina Mäki, newly appointed Baltic Sea Challenge coordinator; Eliisa Punttila and Tina Nyfors, CITYWATER project experts. Aninka Urho from HSY (furthest to the right) guided the group.

Photo: Tina Nyfors

Read more: Viikinmäki WWTP