Wastewater treatment plants become equalization reservoirs with WaStop

Municipality of Karlshamn, Sweden
Mörrums reningsverk, Karlshamn in Sweden

Since 1966, Mörrum's waste water treatment plant was used to treat wastewater from the village of Mörrum, in south east of Sweden. In November 2019 it was deemed that the treatment plant was outdated and extensive renovations would be needed to keep the plant running. Karlshamn Municipality decided instead to centralize the treatment of wastewater to Sternö treatment plant in Karlshamn instead as the Sternö facility that has undergone major renovations and was now able to treat a larger amount of incoming water. A pump station was built to transfer the wastewater from Mörrum to Sternö.

Karlshamn Municipality decided to utilize the ponds at the treatment plant Mörrum in as equalization reservoirs during periods of high flow through the new pump station. To keep maintenance to a minimum staged filling was to be implemented so that one pond at a time was filled before the waste water goes on to the next pond and so on. Solutions were investigated to most effectively use the facilities in the best manner.


Karlshamn Municipality contacted Wapro for advise and was recommended to use several WaStop DN300 inline check valves between the ponds to achieve the staged filling and emptying.

At time of peak flow when the pump station is overloaded the overflow flows into the first basin, then overflows into the second basin and so on. WaStop inline check valves are utilized to prevent the wastewater from flowing into all the pools simultaneously. Having staged filling means that the minimal number of ponds are used which leads to reduced maintenance in the plant.

When inflow to the pump station is reduced the WaStop’s allow the wastewater to flow from the ponds back into the pump station to pump further on to Sternö Treatment plant.

Repurposing the treatment plant in Mörrum with the use of WaStop, has protected the environment and utilized resources without increasing maintenance and costs.


Acquire the -file.

Please enter your e-mail to a download the file for .dwg.
Please provide your e-mail and location to view the drawing for .pdf.
Your -file is ready for download

Processing your request

Processing your request

Please wait while we prepare your download.
Please wait while we prepare your file in a new tab

Download has started

is available

Your download for the file .dwg has started.
Your drawing for .pdf has been opened in a new tab.