Frequently clogging wastewater pumps can lead to costly maintenance and downtime, and can also waste a significant amount of energy. Find out how wastewater pumping stations around the world are benefitting from smarter pump designs and controls.
The wastewater pumping stations in Jefferson Parish, Louisiana, had been experiencing serious clogging issues. The costs and man-hours associated with maintenance – not to mention the need to carry out daily inspections at every facility – had been adding up.
“Our focus has been on finding reliable replacement pumps, because we have so many lift stations with clogging problems,” said Linda Daly, director of the Parish Department of Sewerage. With more than 500 pump stations in the parish, Daly decided to test Xylem’s Flygt Experior pumps at four pumping stations.
Xylem’s Flygt Experior system was installed on all the pumps last May, while three of them were also fitted with Flygt SmartRun controls. Since the installation, the pumping stations have not required a single maintenance call, and overall the systems have delivered a 50 percent saving in energy consumption.
“We’ve not had any call-outs for pump failures at the four locations that received the systems from Xylem, despite heavy rains and ‘inflow and infiltration,’” says Daly.
Three key components
The success of the Flygt Experior in Jefferson Parish can be attributed to three key components: hydraulics, motors and controls. Regarding the hydraulics, Flygt Experior uses Flygt N-technology with a self-cleaning, clog-free impeller, which enables sustained high efficiency. The motor was built utilizing cutting-edge calculation programs to specifically meet the requirements of wastewater pumping.
Finally, the Flygt SmartRun controls have been specially designed always to search for an optimal “duty point,” in order to minimize friction losses and maximize the efficiency of the pump system. Pre-programmed with key wastewater pumping functions, Flygt SmartRun helps ensure the full benefits of variable speed pumping.
An energy consumption test
At a municipal wastewater pumping station in Dalarna, in central Sweden, most of the losses experienced by the station were in the form of friction losses. The station also has to deal with huge variations in inflow, which increases dramatically during the spring, when the snow is melting, or following heavy rainfall. Over-sized pumps had therefore been installed to prevent flooding – although they consume more energy than necessary when running at normal inflow.
An energy consumption test was carried out at the station, using a Flygt N-pump and a competitor pump, operating alternately. After Flygt SmartRun was installed to control the Flygt N-pump, the competitor pump was switched off and energy consumption was measured again. The results spoke for themselves – the Flygt N-pump with the Flygt SmartRun controls was delivering a comparative energy saving of almost 50 percent.
“Today there are generally two types of controls for wastewater pumping systems,” says Anders Fredriksen, head of Xylem’s wastewater transport business area. “Conventional on/off controls, which are simple to use but give limited opportunities to optimize functionality, and variable frequency drives which provide more fine-tuning possibilities but can be complicated to install and difficult to optimize. SmartRun solves this issue by combining the advanced functionality of a drive with a simple intuitive interface. While the internal functions are multifaceted, the interface is simple to operate.”