Pumping operations galvanised to deal with aggressive wastewater fluids

Paul Boughton
AHC Benelux, a specialist in the provision of surface treatment technologies for engineering applications, has installed a Series 521F/RC close-coupled peristaltic pump from Watson-Marlow Pumps Group to help process aggressive wastewater fluids produced by various plating and galvanising processes.

AHC Benelux is part of Aalberts Industries (AI). Employing around 90 people at two sites in the Netherlands (Eindhoven and Venlo), AHC it is a leading European supplier of functional surface and heat treatment processes.

Eindhoven alone has eight flexible production lines running 24 hours a day, with processes such as electroplating silver, gold, copper and tin, electro-less nickel and synergetic coating, taking centre stage. AHC in Venlo has large, fully-automated lines and focuses primarily on technical and hard anodising, synergetic coatings, electro-less nickel on steel, as well as specific treatments such as chromic acid anodising, chromating and lacquering. AHC’s customers come from a wide range of sectors: everything from automotive, electronics and aerospace, through to pharmaceutical and food and beverage.

“Running these continuous coating operations produces wastewater that needs to be treated before disposal in accordance with environmental regulations,” explains Luc Heldens, Supervisor Chemicals and R&M at AHC Benelux. “Both sites are certified to ISO 14001 and we take great pride in our ‘green’ credentials. To prepare process wastewater for disposal, both hydrochloric acid and caustic soda (sodium hydroxide NaOH) are used to ensure pH is maintained at regulatory levels.”

Mr Heldens has over 15 years’ experience in managing and optimising chemical and R&M processes. At AHC, his other responsibilities also include purchasing chemicals, troubleshooting and environmental co-ordination.

Originally, an air-operated diaphragm pump (AOD) was considered for the task, but as wastewater from production contains around 33 per cent acid chloride, solids in the acid would destroy the pump’s membrane. The AOD would also be unable to ensure accurate dosing of both hydrochloric acid and caustic soda – and this would cause unwanted fluccuations in the pH levels.

The company initially worked with a competitor supplier of peristaltic pumps but switched to Watson-Marlow because of long delivery times. The first Watson-Marlow baseplate pump was installed many years ago. Today, having reached the end of its natural life after many years’ reliable service, AHC had no hesitation in returning to Watson-Marlow to order another, this time in the form of a Series 521F/REC close coupled pump, specifically designed for demanding industrial applications.

Featuring high performance engineered plastics and a stainless steel pumphead, easy set-up and maintenance are critical features of this innovative peristaltic pump, which is particularly suited to aggressive fluids. Its high resistance to chemical attack makes it rugged enough for the harshest environments, delivering cost-effective, precise pumping and a long service life.

In peristaltic technology, nothing but the hose or tube touches the fluid, eliminating the risk of the pump contaminating the fluid, or the fluid contaminating the pump. Fluids are drawn into the tube, trapped between two rollers, and expelled – the complete closure of the tube gives the pump its positive displacement action, preventing backflow and eliminating the need for check-valves.

“We installed the 521F/REC pump fitted with Marprene thermoplastic tubing elements in February 2010 and it has since performed extremely well,” says Mr Heldens. “It’s pumping hydrochloric acid for about an hour a day – and caustic for around 15 hours a day. The pump is linked integrally to our pH controller and I have to say we’ve had no issues whatsoever with reliability, it simply runs as required without any need for intervention, it ensures a high level of chemical resistance, is easy to operate and needs very little maintenance. Another significant advantage of using tube elements is the longer lifetime of the tubing and the ease with which we can replace it.”

For more information, visit www.wmpg.co.uk

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