Environmental Services

Sewage Tunnels at the Blominmäki Wastewater Treatment Plant

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.

Tampere Central Wastewater Treatment Plant

Construction of the Tampere Central Wastewater Treatment Plant began in 2018 and is expected to be commissioned in 2024. The Tampere Central Wastewater Treatment Plant will be excavated in rock to create stale conditions for the operation of the treatment plant, so that treatment processes are not disturbed or slowed down due to weather variations.

The planned Central Wastewater Treatment Plant uses the latest treatment technologies in order to keep the discharge load on the lake to a minimum. The activated sludge process is supplemented by sand filtration and UV disinfection. The treated wastewater is led to Lake Pyhäjärvi by means of a tunnel excavated in the bedrock and a discharge pipe.

The progress of the excavation of the Tampere Central Wastewater Treatment Plant can be monitored through the environmental monitoring system, EMO (Environmental Monitoring Online), developed by Kalliotekniikka Consulting Engineers Oy.

In the design of the Tampere Central Wastewater Treatment Plant, special attention has been paid to a possible future expansion.

West Metro

The West Metro extension has been one of the most talked about projects in the Helsinki metropolitan area in recent years. The 21-kilometer-long West Metro extension, which includes 13 new stations, has provided work for many design offices.

Rockplan’s Juha Salmelainen was responsible for the principal design of the rock mechanics and tunneling (PS-KAT) for the Ruoholahti – Matinkylä section of the first phase, which was commissioned in 2017. The rock mechanics and tunneling design of the Ruoholahti – Keilaniemi section was the responsibility of the consulting consortium FKW, which consisted of Finnmap Infra, Kalliosuunnittelu Oy Rockplan Ltd and WSP Finland Oy.

In the second phase of the West Metro extension, the Matinkylä – Kivenlahti section, Rockplan is part of the consulting group Sigma and is responsible for the rock mechanics and tunneling design for the Kivenlahti metro station and the structural design for the Kaita station. The Sigma consulting group consists of Finnmap Infra Oy, Kalliosuunnittelu Oy Rockplan Ltd, WSP Finland Oy, Sipti Oy and Saanio & Riekkola Oy. Phase 2 traffic is scheduled to begin in 2023.