Keski-Suomen Betonirakenne Oy (KSBR) and the UPM Jämsänkoski paper mill in Jämsä, Finland, have signed a contract on the construction of a new primary settlement tank for the paper mill’s wastewater by next autumn.

Primary settlement is the first stage of wastewater processing in which solids are separated from the water before biological treatment. All waters from the mill area run to primary settlement, and the next processing stages require the primary settlement to function smoothly and without interruptions.

“In addition to the excavation and concrete structures related to the tank, we will also build a new pressure pipeline. The work started this spring,” says KSBR Project Manager Petteri Mäkelä.

The round tank has a capacity of about 4000 cubic metres. The tank project requires about 800 cubic metres of concrete and 115,000 kilograms of reinforcement steel.

“In the pressure pipeline contract, we will dig 650 metres of new pipelines and install a total of 3,300 metres of pipes,” Mäkelä counts.

There was clear demand for a tank that would serve three paper machines.

“Our former primary settlement tank is about 50 years old, which is why its structures started to be in poor condition,” UPM Project Manager Kari Mäki explains the background for the project.

Involvement at the design stage

KSBR and UPM Jämsänkoski agreed on the contract exceptionally early on, last autumn, even though the worksite was planned to begin only this spring.

“It’s our investment policy that the selection process for the main contractors should have advanced as far as possible when the investment is being approved. We have noticed that it’s a shortcoming when you plan first and only then start choosing contractors. Often, contractors can present good ideas in the planning stage, which help save costs and make the construction easier. With KSBR, it looks like we will be able to manage with smaller units, and the project is not bloating,” Kari Mäki states.

“Our Project Manager Marko Koskinen was involved in steering the design. We were allowed to present our ideas for the casts and seams of slabs and walls and the structural strand technique and its details. With specific solutions, we were able to shorten the construction schedule by several weeks,” Petteri Mäkelä says.

The design steering paid special attention to the KSBR personnel who do the formwork and reinforcements. For example, the form technique to be used is anticipated in a large part of the structures early in the planning stage.

Praise for the culture of safety

In May, prestressed wall structures of the tank were in progress. At this point, KSBR is ahead of schedule and looking to complete its part of the project in early August. After that, it is time for equipment installations in the mill.

“We have patted ourselves on the back for our excellent choice of contractor. The cooperation has gone smoothly. The professionals are extremely skilled, and KSBR’s supervisors have been on-site the whole time,” Kari Mäki praises.

He also thanks the contractor for high-quality reporting and a culture of safety.

“Our mill is very focused on safety. We do a safety inspection round once a week, and we have been impressed by KSBR’s focus on safety at work.”

KSBR aims for an accident-free work community where employees get to go home healthy every day and health risks are prevented in the long term, as well.