How to extend the life of your water purification system

Most high-quality, high-volume water purification systems for industrial and healthcare applications have a design life of around ten years. After this point, although systems can often continue to function satisfactorily, the original manufacturer’s guarantees are likely to have expired, servicing costs will begin to rise and spare parts will probably become increasingly difficult to source.

Before thinking about an expensive and potentially disruptive system replacement, however, it is worth considering ways in which the operating life of existing equipment can be extended. In many instances, this can add five or more years to the lifetime of water purification devices, without impacting water quality or significantly increasing operating costs.

Service and maintenance
The secret of system longevity is routine (scheduled) maintenance. Just like any mechanical device – from your central heating boiler to your car – reliability depends on regular servicing, to change consumables, adjust settings and inspect for possible wear that might cause a problem in the future.

Although most servicing is normally carried out to an agreed schedule based on factors such as demand, time on-line and feedwater characteristics, we are increasingly seeing a move to predictive (rather than time-based) maintenance. Predictive maintenance uses condition monitoring techniques to detect gradual changes in pre-determined equipment criteria, such as vibration levels in rotating equipment (e.g. pump bearings and shafts), and then to use this information to establish the best time to carry out maintenance. This proactive approach can significantly reduce service costs, improve uptime and extend system life. It is becoming an increasingly attractive option thanks to the proliferation of low-cost intelligent sensors and monitoring instruments, with wireless communications and remote diagnostics. The growth in machine learning and artificial intelligence (AI) are likely to accelerate this trend.

Protecting the RO membranes
Most industrial water purification systems will generally incorporate one or more reverse osmosis membranes. These may be single or double-pass devices, but in each case their operating life will be dependent on a number of factors, of which the quality of the feedwater is critical. This will have been considered at the initial system design stage and suitable pre-filtration and, if required, carbon removal units will have been installed. However, if these are incorrectly maintained then inevitably the performance of the membranes will be adversely affected, with a fall in the level of salt-rejection and the quality of the permeate, or a reduction in flowrates.

Under normal operating conditions, and with the correct maintenance, RO membranes will typically last between five and seven years before they need to be replaced. Replacement is normally straightforward and can be scheduled either as part of a routine service visit or at a time when demand is likely to be low.

Prefiltration systems, such as particulate filters should be changed more frequently, perhaps annually. They are designed to remove debris and particulate matter from the feedwater and can easily become clogged, which can reduce the flow rate to downstream devices. Similarly, activated carbon filters used to dechlorinate the feedwater – especially if this is from a municipal supply – will need re-bedding every one to two years, depending on the concentration of chlorine. If an ion-exchange unit is installed to soften the feedwater, then this will also need resin replacement, usually after a few years.

Monitor and test
It should go without saying that systems should be given basic checks at regular intervals to make sure that seals and pipework are not leaking. Similarly, operating parameters such as flow rates and water purity should be carefully monitored. In some applications – notably healthcare and pharmaceutical manufacture – where water quality is critical, testing must be carried out at mandated intervals and using approved instrumentation. Even in less critical applications it pays to monitor water quality as a matter of routine production operations, to ensure that process or product quality is not affected by a change in the operating conditions of the water purification plant.

Use the experts
Few organisations that rely on a supply of high-quality water are experts in water purification – the water supply is generally seen as a raw material or utility required to support a downstream process or production operation, and its management is rarely seen as a core business skill.

It therefore makes sense to partner with a specialist water engineering supplier, with the knowledge, experience and resources to maintain water purification systems in optimum condition – regardless of age – and provide 24/7 cover for critical applications.

Our team of service engineers can provide lifetime support, both for our range of Purite water purification systems and for equipment supplied by other manufacturers. We have a wide range of service options and dedicated packages, including telephone support and 24/7 on-site cover.