On the southwest coast of Finland, the country’s third largest City, Turku, is located. As the oldest city in Finland, the town has seen lots of change throughout the years and has had to continuously adjust to developments in technology and infrastructure. An integral part of that infrastructure is the wastewater network. To keep up with an increasing population size as well as ever-stricter regulations and environmental concerns, Turku Region Wastewater Treatment Plant Ltd. is always looking for ways to optimize and to futureproof their operations.

Jarno Arfman, Technical Manager Turku Region Wastewater Treatment Plant

Increasing levels of solids caused clogging of wastewater pumps

At the pumping station seven kilometers from the Turku Wastewater Treatment Plant, a 75 kW pump used to be one of five pumps employed to send water to the treatment plant. However, due to increasing levels of solids in the wastewater, the pump would clog regularly claiming several hours of a staff member’s time for manual unclogging.

In addition to that, the energy consumption of the 75 kW pump was higher than what was ideal.

“Just as every other business today, we are continuously looking into ways in which we can lower our energy consumption because pumps generally use a lot of energy. So when Grundfos suggested replacing our 75 kW pump with a 63 kW pump and promised that it would be able to maintain the same flow, naturally we were intrigued,” explains Jarno Arfman, Technical Manager, Turku Region Wastewater Treatment Plant.

Grundfos SE with Open S-tube® impeller eliminates clogging

As part of a field test of the new SE/SL Range 56 wastewater pumps, Grundfos suggested testing a 63 kW Grundfos SE with the innovative Open S-tube® impeller design to prevent clogging and increase efficiency in the installation.“Before launching a new product on the market, we want to verify that the product lives up to our expectations and performs as promised outside of our controlled testing facilities.

For that purpose, we prefer a complicated installation where we can really test the limits of our new design, and the Raisio pumping station was perfect for that,” explains Mikael Hirvonen, Sales Engineer, Grundfos.

Thanks to its remarkable self-cleaning abilities, the 63 kW SE pump is able to efficiently handle wastewater containing sediment while using less energy than the old pump and without clogging.

Mikael Hirvonen, Sales Engineer, Grundfos.

Open S-tube® impeller prevents clogging

The Open S-tube® impeller from Grundfos is engineered to prevent clogging. The semi-open impeller blades work towards the adjustable suction cover that is equipped with a spin-out groove ensuring that all fibers are transported away with the sewage water. This prevents the accumulation of sediment and ensures a continuous flow of solids towards the pump discharge, optimizing the process for maximum efficiency.

Jarno Arfman, Technical Manager Turku Region Wastewater Treatment Plant

Increased efficiency and zero clogging incidents

Two and a half years in, the field test has been a success for both Raisio pumping station and for Grundfos. Without a single clogging incident, the new pump is making daily work at the pumping station more efficient and hassle-free. Furthermore, it has helped ensure energy savings of upwards of 30,000 kWh per year.

“We are saving money, consuming less energy, and we have eliminated the clogging issues we were experiencing before, so all in all, I am very happy with this new solution,” says Arfman.

“We are very satisfied with the performance of this Grundfos SE Range 56 pump. The Open S-tube® impeller has really proven its self cleaning ability.”