Sludge pumping perfection

Xylem recently published the Flygt Handbook of Sludge Pumping, a reference work filled with case studies, in-depth knowledge and engineering expertise. Impeller spoke with Magnus Fahlgren, the editor of the book and an application engineer at Xylem.

By Chad Henderson

Magnus Fahlgren loves water – or rather, flowing water. He started working as an engineer at Flygt, now a part of Xylem, in 1986, following research work in the area of turbulence and hydromechanical issues.

“When I walk in the forest or in the mountains and see a stream, or when I see water flowing under the bridge by Stockholm’s castle, it’s beautiful to me,” Fahlgren says. “Even when I see waves travelling over a lake. That you can partly predict what is going to happen in those water systems by applying physics is really cool.”

Predicting what will happen in different fluid systems, of course, is one of the focuses of the Flygt Handbook of Sludge Pumping that Fahlgren and several researchers at Xylem recently produced.

“The main purpose of the handbook is to provide background knowledge about how to create a good pumping system,” says Fahlgren. “You think about how much electricity goes into a cable, but you don’t often calculate how much it costs when a pump clogs, how much it costs to service and replace it. This handbook presents key issues to be aware of when designing pump systems.”

Performance and risk management

Fahlgren is quick to point out that sludge pumping is about more than planning the flow of water. “Often pumps are tested with water, but the sludge we come across is usually water with a lot of other ingredients in it,” he says. “This affects the properties of the liquid, its viscosity, which affects the requirements of the pump, the transportation system and the containing tanks. The trick is to predict how much the performance will go down once you add other ingredients,” he says.

Fahlgren says that risk management is also something that companies need to carefully consider when designing sludge pumping systems. “They must inform themselves about the consequences if the system stops working,” he says. “Based on such a risk, they should take countermeasures. If a breakdown has catastrophic effects, then the safety margins must be much higher than if it just requires a restart of the pump.”

A reference work for the industry

One reason for making the Flygt Handbook of Sludge Pumping, says Fahlgren, was to create a reference work on sludge pumping that could be used by all professionals working in sludge transportation, including consultants, engineers, and others in charge of running and designing pumping systems. “There was some research and development made locally for this, but for the main part it is knowledge that is available to everyone but spread out all over the world,” he says. “We wanted to collect all this information in one place.”

For more information about the Flygt Handbook of Sludge Pumping visit: www.flygt.com

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