The sewage tunnels of the Blominmäki Wastewater Treatment Plant consist of an inlet tunnel leading to the treatment plant and a discharge tunnel leading out of the treatment plant. A total of about 20 kilometers of inlet and discharge tunnels and associated access tunnels will be excavated.
In addition to the tunnels, the contract includes maintenance and emergency exit shafts that are critical for safety, the Suomenoja Acceleration and Drainage Pumping Station built within the rock as well as its associated above-ground shaft access buildings, and a challenging connection to the existing offshore tunnel. The offshore tunnel directs treated wastewater 15 kilometers to the sea.
Rockplan was also involved in the general design phase when a suitable site was sought for a new wastewater treatment plant in Espoo. There were five alternative locations under review.
The contracts are estimated to be completed in the summer of 2021. In 2022, the new Blominmäki Wastewater Treatment Plant will treat wastewater from 400,000 inhabitants in the Espoo, Kirkkonummi, Siuntio and West Vantaa areas.
