Dosing pumps facilitate ‘ready-made’ effluent treatment plant

Paul Boughton

Neutralac SLS45 high strength liquid lime from Lhoist UK Ltd is proving an irresistible solution for process plants requiring improvements in their effluent treatment procedures.

This is not only due to the innovative properties of Neutralac (45 per cent solids by weight, 300 Cps viscosity and 5 second KIWA reactivity), but the ability of Lhoist to supply customers with a field trial equipment package tailored to specific needs. The delivery technology is a Watson-Marlow 720UN/RE high flow dosing/metering pump and Lhoist has already acquired six since the project commenced in 2012.
According to Product Manager, Derek Thompson, Lhoist developed Neutralac to address the fact that lime is often seen as a low grade commodity.
“Neutralac is different,” he states. “It allows us to attack the caustic soda market at the high end of effluent treatment. Here, neutralising agents such as caustic soda and magnesium hydroxide are aggressive and can easily damage both operators and plant, hence a comparable alternative is highly desirable. Neutralac is safer to use than caustic soda and other alkali alternatives, with equal or better performance.”
The Lhoist Group has operations throughout Europe and America, with a total headcount exceeding 7000. Around 100 are employed in the UK, at a quarry near Buxton and at a satellite site in Cumbria. Lhoist invests heavily in R&D, and Neutralac is among the latest products to make the transition from laboratory to production.
“We knew we couldn’t just sell it in bottles or IBCs and expect sales to take off,” explains Mr Thompson. “We had to take it to customer plants and provide delivery and analysis equipment on site. As a result, a lightweight yet robust pumping solution was sought, with peristaltic technology from Watson-Marlow proving the optimum solution.”
The service and technology offered by Lhoist means that a company such as a metal finishing plant, for example, where strong acids are used to etch metals prior to plating, can now process its effluent stream easily and cost effectively. Lhoist will arrive on site with a ready-to-go system comprising Neutralac, pH control and delivery equipment, essentially supplying a small, pilot-scale effluent dosing plant.
“We selected a peristaltic unit because they offer the easiest and best way to pump slurry around,” says Mr Thompson. “Neutralac lime suspension is fairly thick and the pumps are often sited outdoors. However, the Watson-Marlow 720UN/RE is a work of art – it’s tremendously flexible yet extremely robust and reliable. In addition, they are easy to hook up with pH controllers – either our own meters or those used by the end user.”

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