The reliable and safe performance of wastewater systems is seen as key to ensuring water conservation and the maintenance of high water quality in South Africa.

The Grundfos SE/SL range of wastewater pumps are designed to allow solid objects and rags to be passed quickly through the pump without causing a blockage or shutdown of the motor and are now fitted with the Open S-tube impeller designed for greater durability and reliable performance.

“As the level of solids in our wastewater rises, this innovative pump design can make wastewater plants and pump stations much less susceptible to stoppages and overflowing,” explains Grundfos sales director water utility South Africa Bennie Thiart. “Our design allows even stringy material like rags to be passed quickly through the pump without causing a blockage or shutdown of the motor.”

He highlights that wastewater treatment plants and pump stations operated by municipalities or industry can cause considerable environmental harm when they overflow due to pump stoppages. When there are unexpected disruptions to pumping, waste water can flow into rivers and wetlands leading to contamination of groundwater aquifers.

“We can expect stricter enforcement of environmental legislation, as South Africa’s water resources are currently under pressure,” he says. “Wastewater treatment plants, for instance, can no longer afford the risk of spillages.”

“Our development of the latest generation technology first required extensive virtual simulation,” he adds. “We then spent the past two years testing actual prototypes in the field and the results have been up to our expectations.”

Hydraulic performance tests on the SE/SL range have followed the ISO 9906 standards, among others, while clogging tests are conducted according to the methodology developed by the Technische Universität Berlin.

Critical to the design is the quick expulsion of solid material and objects from the pump, to avoid raising the torque to levels that will trip the motor. This functionality can be enhanced by fitting a guide vane to the pump.

A monitoring and control system allows pump performance to be remotely tracked and generates early warning signals for operators in case of any changes in the operation of the pumps.