The challenge was to provide the operator with a cost-saving solution for the installation of new propeller pumps while at the same time modernizing the switchgear.
Waste water and sewage systems
As one of 374 pumping stations in Schleswig-Holstein, the Ockholm pumping station is responsible for keeping land areas dry that lie below sea level in places and are used year-round by farmers, among others. The three powerful pumps at the Ockholm plant in northwestern Germany pump up to 16,200 m³/h from the interior of the country toward the North Sea. Following the failure of a long-shaft propeller pump in 2019, the pumping station was to be equipped with submersible motor technology and at the same time modernized with new, modern switchgear technology (frequency converter, soft starter, radar level measurement) and high-voltage supply.
For this purpose, Alfred Kleu, Head of Sales Special Solutions, in close cooperation with Jürgen Steiner (both HOMA), created a cost-saving and efficient solution for the aging plant. The dry-installed long-shaft propeller pumps were replaced by a 584/21-H238/CS submersible propeller pump. The client's requirement was to continue using the DN 900 riser pipe, which was still in good condition. Detailed drawings were no longer available, so the riser was remeasured at great expense. Knowing the spatial possibilities, distances to the ground were determined, among other things, and an individually designed coupling ring was developed, which was mounted between the riser flanges. This design avoided time-consuming and costly re-piping of the bailer, while simplifying future maintenance and repair work by changing from dry to wet installation. Within the project, the now enlarged switchgear/control system was relocated from the plant building to a purpose-built annex. The positive consequences of the renovations are lower maintenance costs, among other things through remote maintenance, and minimized operating costs thanks to modern, power-saving technology. This is because the power required by a pumping station is enormous: in order to pump the large quantities of water, electricity costs of a not inconsiderable amount are incurred each year. Accordingly, the reduced electricity consumption and the resulting cost savings are positive side effects of the modernization measures. Since completion of the project, the pumping station has been running trouble-free. For the Südwesthoern-Bongsiel dike and main stem association and HOMA, the project is thus the fifth successful collaboration in five years.