Pumps switch at Australian water treatment plant

Sydney, Australia – An Australian water treatment plant has significantly reduced its downtime and maintenance costs through the adoption of hose pumps in various parts of its process

The water treatment plant at Kembla Grange has tough requirements for its pumps, including pumping abrasive lime slurry and corrosive chlorine solutions, which were causing expensive and inconvenient failures of existing pumps.

Located near Sydney, the water treatment and filtration plant at Kembla Grange is operated by Veolia Water. It produces 210 ML/day of high quality drinking water across the Illawarra region on behalf of Sydney Water.

Originally, two progressive cavity pumps had been specified and installed at Kembla Grange for dosing lime slurry, which is used to maintain and control pH in water. However, the abrasive nature of the substance wreaked havoc on the PC pump’s rotor and stators.

It was hard to maintain the set-point flows and there were constant blockages, noted Pino Taglieri, the plant’s operations supervisor.

“Depending on the demand we’d go through rotors and stators every couple of months, which was a costly exercise. On top of the parts, it would take two guys two hours to fix, plus the hassle of cleaning the lines,” he said.

The operator opted to replace the pumps with Bredel SPX50 hose pumps from Watson-Marlow.

“When you add up the ongoing hassles of other pumps types, it became evident that Bredel pumps were our preference,” says Pino Taglieri, the plant’s operations supervisor. “The nature of the hose pump - it just pushes the lime aside with its shoe, they’re gutsy and get the job done.”

The inherent design of Bredel hose pumps means there are no intrusions in the flow path, eliminating any risk of blockages. This makes them suitable for handling problematic fluids such as abrasive lime, chemicals or sludge with high solids content.

It was a similar story in another part of the plant where two piston diaphragm pumps were originally specified and installed to pump a chlorine solution into a 750mm main at 16 bar. Chlorine is a corrosive disinfectant, in effect bleach, making it a tough application.

“These pumps were a nightmare to maintain, the amount of time and effort involved as well as getting the parts. It would take up to a day and a half to get each pump up and running; from the set-up, the timing, etc.” said Taglieri, who again turned to Bredel pumps for the solution.

Bredel pumps are self-priming and dry-running, making them easy to start and stop. Relative to other pump types, Bredel hose pumps have one wearing part - the hose. In this instance, the two SPX50s installed at Kembla Grange were fitted with Hypalon hoses, which offer good chemical resistance.

“They last 3-4 months and take an hour to switch out - what a difference it has made,” said Taglieri.

The pump supplier’s links to Kembla Grange date back to the design phase of the plant in1996. Then a Bredel SP100 sludge pump was installed in the drying bed area, and said Taglieri, the site has only had to replace a single hose from wear over a 16 year period.

“We have an old 100mm Bredel pump used to transfer very thick sludge that is indestructible,” he confirms. “It is turned on for only 2-3 hours a week, but literally we have serviced it twice since it was commissioned. The first time was due to operator error, the second time it was from wear, that’s it.”