Rotary lobe pumps help to reduce downtime

Paul Boughton

Michael Groth reveals how rotary lobe pumps are improving operations at a wastewater treatment plant in the USA

At a main wastewater treatment plant serving a city in the state of Delaware in the USA, plant operators turned to rotary lobe pumps with full-service-in-place (FSIP) design to replace existing pumps, leading to a decrease in maintenance and downtime.

The wastewater treatment plant included a high-rate activated sludge plant, three pump stations, industrial pre-treatment program, industrial leachate and sludge disposal. Netzsch provided the company with new pumps that have greatly lowered maintenance and downtime in two different sludge-handling applications, involving transporting thickened sludge and digester recirculation. 

The first Netzsch Tornado T2 pump with an FSIP design replaced an existing pump that wasn’t working to the customer’s satisfaction. The plant operators then also replaced a second pump with a Tornado T2. The plant operators recall that the two previous pumps would go down approximately every three month and the longest running pumps would last about one year. The two new pumps have now been running continuously for two years. Two seals were replaced in that time, but with easy access through the faceplate, that was a simple operation. 

Digester circulation line benefits
According to one of the plant’s maintenance engineers, some of the sludge digesters have always had problems with gas bounding. The plant had previously been using recessed impeller centrifugal pumps. The Netzsch pumps that replaced these pumps have been running almost six months in the sludge circulation application without any downtime and have completely solved the air-bounding problem.

Another advantage the plant has noticed is that as the Netzsch pump is belt-driven, there is no oil. Plant operators don’t have to worry about putting in the wrong oil or running out of oil. There is a small container that puts a small amount of oil on the seal – but that’s it. 

Plant maintenance staff regularly check the pumps to see if the lobes need to be changed, but staff report that the lobes are not yet showing any signs of wear.

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Michael Groth is head of Business Field Environmental & Energy at Netzsch in Germany.

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