Where is pool filtration heading?

There is an increasing range of filtration options for both new and refurbishment projects and making the correct choice is crucial for water quality, capital and operating costs, and sustainability.  So what does the future hold and how does one navigate all the suppliers claims and promises?

Firstly a recap on sand which is the go to choice for filtration, widely used all over the world. When properly designed and operated, sand filters produce excellent water quality, helping to keep turbidity under control, and crucially the removal of the parasitic cryptosporidium oocysts. And they can be an optimum sustainability choice.  What more can we ask for?

Traditional sand filters

Well, with the exceptions of refinements to construction and flocculation, and the use of recycled glass media in lieu of sand, not a lot else has changed much with sand filters over the last 100 years.  And while they are very well understood and are very reliable they do have significant disadvantages such as bulk, weight and the logistics of handling large volumes of backwash water.

The future is exciting and amongst the myriad solutions here are 3 of the most viable:

• Regenerative media filtration (RMF) – a well established process that uses septa coated with Perlite media to provide for a very fine filtering layer typically inside a filter vessel; water quality comparable to sand, a key benefit is that ‘backwash’ water volumes are a fraction of sand filters (though keep in mind that water for dilution is still required); at least two suppliers into the UK market
• Ceramic membrane filtration (CMF) – typically utilising robust silica carbide membranes with specific membrane pore sizes to provide a fine filtering membrane; various claims are made but key benefits include modular construction, lighter structural loads and smaller but frequent backwash water volumes; membrane suppliers into the UK market include Liqtech and Saint Gobain; a technical solution beyond sand, there is much to consider
• Drum filters – these offer an established filtration approach with the key benefit of very low head loss through the plant; no known pool applications in the UK, but are in use in some Scandinavian countries; need to be considered at the early design stage; one to keep an eye on

Ceramic membrane filter

How to decide which filtration approach to use? Our research and feedback from operating sites clearly indicates that while there are benefits to consider with the more complex CMF and RMF options, the choice of filtration system is often project specific.  Also it is important to be able to interrogate the various claims being made, to check if they are true.  At Devin, we analyse every project to ensure it gets the right solution in terms of quality, sustainability and cost, and ultimately save carbon and money.

Drum filter

Tom Devin will be speaking during IAKS Congress week at the FSB/Aquanale International Swimming Pool and Wellness Forum (ISWF) in Cologne on the topic of ceramic membrane filtration in the UK.  You can see Tom speaking on Wednesday 29^th October at 11.00am in Hall 7, C40/D41.