Efficiency is key

Phil Bolton, water industry specialist at Watson-Marlow Bredel Pumps, explains how peristaltic pumps can deliver reduced cost of ownership

Rising prices and dwindling resources mean resource efficiency is a key priority for water companies. And new regulations are likely to create further pressures for pump accuracy and effectiveness. Keeping stakeholders satisfied, making a profit, and observing increasing restrictions makes life a constant juggling act for UK water companies.

“Companies have a responsibility to challenge their own operational and business strategies and practices,” a spokesman for Water UK says. “Climate change, housing growth, concerns about water resources and reliability of supplies, affordability and financing pressures are all driving companies to search for new ways of managing assets.”

Driving costs down in the purification and production areas means the money saved can be invested back into such vital programmes as leakage reduction and pipe replacement.

One major area that can reduce costs is in equipment choice. Making long-term, well informed decisions on pumping technology can mean a massive reduction in labour, maintenance and ease of use – as well as cost.

In the water industry, pump selection is a complex task. With so many products to choose from, such varying costs and so many specific requirements, it is no easy decision. In the past, the multitude of options available meant purchasers made their choice by selecting the cheapest design for the short term – often to their long-term detriment. However, with maintenance costs rising, pump buyers are considering whole-life costs and realising that the false economy of the cheapest up-front option is no longer a viable decision.

Previously the absence of sufficiently robust analytical tools meant that buyers were more or less compelled to adopt a simplistic approach by focusing solely on accessible and easily identifiable energy costs. More sophisticated assessment tools allow the input of a wide range of complex variables. And so a more accurate analysis of whole-life or life-cycle costs for pumping technology can now be generated. This has highlighted the fact that using initial purchase price and energy costs as a benchmark can significantly skew the selection of the most cost-effective equipment in the long term.

The effect of this approach has been to mask hidden costs which if made explicit would render many earlier purchasing decisions uneconomic.

In comparison with other pumping technologies (e.g. diaphragm, centrifugal and submersibles), the relative lack of complexity in peristaltic pumping technology makes it increasingly the first choice in the water and wastewater sector due to its simplicity of design, ease of maintenance and long-term cost effectiveness. These high-flow, high-pressure pumps are used in various stages of wastewater treatment including metering and transferring a wide range of harsh and aggressive materials. They have the ability to provide extremely accurate dosing measures – they can deliver either a teaspoon or a tanker-load of chemicals and at variable rates according to weather conditions, time of year and so on – and pumping volume: from microlitres to gallons per hour.

Intelligent, automated systems are vital for cutting labour hours and cost efficiency. And a peristaltic pump is able to deliver reliable, consistent results running constantly, without operator intervention.

Also unlike other pump technologies, which have tight tolerances or interference fits of the wetted rotating parts, peristaltic pumps keep extremely corrosive chemicals such as ferric chloride, sodium hypochlorite and abrasive fluids like sludges, lime and powdered activated carbon (PAC) slurries from wearing out pumps’ rotating components. In fact, a properly selected heavy-duty pump hose never fails due to abrasive wear; it only fails due to the total number of occlusions seen in a specific application. Regardless of the product, whether it is abrasive grit in a grit removal system, thickened sludge, lime slurry or nonabrasive polymer, the hose life is the same, offering the kind of flexibility that is likely to become a necessity for water companies in the near future, as regulations become more restrictive.

The fast approaching Water Framework Directive is set to include far stricter regulations on chemical dosing, meaning that accuracy in this area is going to be more essential than ever before – possibly instigating a flurry of new purchasing for those companies with below standard equipment.

Uncertainty and risk surrounding dwindling supply and new regulation is forcing water companies to look to the future and do the same with their equipment. Life-cycle costing (LCC) analysis is ultimately seen as a strategic management tool and in the water sector it is an essential part of budgeting and planning – driven by the sector’s distinct characteristics of increasing demand, limited resource and financial constraints.

Looking at the lifespan of a product and weighing up the overall costs is becoming common practice – particularly in this constantly changing environment. No longer dominated by initial cost, or energy efficiency figures, the water industry is starting to realise that money saved on repairs, replacements and resources far outweigh any short-term gain from cheaper pumps that hold an increased risk of breakdown. All UK water companies have an obligation to provide a 25-year resource plan, revised each year, in which they forecast demand and supply and set out how they intend to maintain security of resource for their customers over this period of time. Knowing that they have reliable, efficient pumping technology which can adapt to future regulations means that the cost of replacing equipment can be kept to a minimum, as can predicted labour and maintenance rates.

When it comes to the bottom line business case, using a company’s infrastructure to its maximum efficiency is key – using pumping technology that minimises downtime, the use of employee resource and replacement costs has a significant impact on the long-term asset base. Forecasting future business variables such as climate change impacts mean that companies have to incorporate risk and uncertainty into their long-term planning strategies. Conventional pumping technology uses valves, seals and associated pipework.

Indisputably, this means that there are more parts that can go wrong. When considered in terms of LCC, which looks at all the components which make up the total cost of pump ownership – including both the internal parts of the product itself and external ancillary equipment – peristaltic pumps have gained growing recognition and uptake from both UK industry and abroad. Peristaltic technology provides water companies with a future-proofing process solution which no other conventional pumping solution is currently capable of delivering.

Visit www.hydrologyweb.pnl.gov or www.europump.org

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