Econet and Jyväskylän Seudun Puhdistamo Oy have signed an extension of the contract for renovating primary clarifiers in Nenäinniemi, Finland.
The Nenäinniemi Wastewater Treatment Plant treats wastewater discharged into the municipal sewerage systems of Jyväskylä, Muurame, Laukaa, and Uurainen. The plant has three similar primary clarifiers, the first of which was renovated by Econet in 2023.
“In connection with the contract for the first basin, we agreed on an option to renovate the next two basins, provided that both the implementation and the technical solutions are successful and sustainable. This was the case, so continuing to work with Econet was a foregone conclusion,” says Markku Tuohimetsä, Maintenance Manager at Nenäinniemi Wastewater Treatment Plant.
Wastewater has been flowing into the plant for 50 years
Econet is responsible for the full renovation as a turnkey contractor: the planning, demolition, concrete, earthworks and installation of the two primary clarifiers built in the 1970s. Econet will also supply the primary clarification equipment.
“Equipment manufacturing is already underway. We are renovating two clarifiers in succession, so two out of three clarifiers will be in operation throughout the project. The renovation project is expected to be completed by the end of September 2024,” says Mikko Syrjälä, Project Manager at Econet.
Easier maintenance and improved reliability
The renovated basins will be equipped with Econet’s clarifiers designed for municipal use.
“They differ from the previously used clarifier model in Jyväskylä in that the blades are fixed directly to the bridge. This significantly reduces the need for maintenance,” explains Syrjälä.
The first primary clarifier renovated by Econet has been in operation throughout the long winter, and its smooth operation has been tested in temperatures as low as 32 degrees (°C) below zero.
“The first installation has been well received. We mainly monitored from the control room window to ensure it was running. From a process point of view, the equipment has also worked as expected,” says Tuohimetsä.
The facts
Jyväskylä Seudun Puhdistamo is known for its efficient treatment process. It achieves 99% removal efficiency for organic matter, phosphorus and solids (required 96% for organic matter and phosphorus, 90% for solids) and 99% nitrification efficiency for ammonium nitrogen (required 80%).
During the open water season, the effluent is also subjected to UV disinfection, after which the treated effluent meets at least the requirements for good bathing water. The treated effluent is discharged into Lake Päijänne via a discharge tunnel and pipeline.
Jyväskylä Seudun Puhdistamo Oy was established in 1971. It is owned by the City of Jyväskylä and the municipalities of Laukaa and Muurame.
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