A stainless steel end-suction Grundfos booster pump is at work in Nafasi Water’s recently-commissioned lime-slaking facility in the Mpumalanga coal mining region. Ashton Drummond, Nafasi Water chief strategy officer, says the new facility serves an important mine water treatment plant in the area and is cutting operating costs. 

“Instead of transporting lime to site in its heavier form – as calcium hydroxide – we can now reduce delivery volumes by transporting calcium oxide and slaking it on site,” says Ashton. “The cost savings make for an attractive payback period for the investment in the lime-slaking reactor.”

Raymond Makgoga, associate sales engineer at Grundfos, says two Grundfos stainless steel end-suction pumps were supplied to the project – one for duty and one for standby.

“The stainless steel is an important requirement due to the corrosive nature of the permeate being pumped into the lime slaker,” explains Raymond. “Our NB/NK stainless steel end-suction pumps are excellent solutions for industrial applications, including where pumping of aggressive media is required.”

The installed pump delivers 50m3 per hour at a pressure of about 4.5 bar. He notes that the pump’s efficiency has been enhanced by an IE3 WEG motor rated at 15kW. The WEG motor was also able to accommodate the plant’s requirement for 525V input.

Nafasi Water’s plant treats mine-impacted water to a high level of quality, allowing it to be discharged back into the river system in compliance with environmental regulations. The quality of the water is, in fact, so good that it is also pumped to the local municipality as drinking water for the community. 

The company’s treatment plants apply its proprietary HiPRO technology (Hi recovery Precipitating Reverse Osmosis), allowing up to 99,5% water recovery from complex waters emanating from mining areas. 


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