Arla Foods
Case Study Dairy Company
client Dairy Company
challenge To utilise free borehole water for site
solution Reverse Osmosis
benefit Elimination of chloride, improved boiler efficiency and reduction in chemical treatment uses
challenge Until recently the producer, home to some of the UK’s leading dairy brands, used mains water in their steam boilers and other applications in their dairy site in Yorkshire. Our challenge was to make the site’s free borehole water supply not just suitable, but more efficient, for use in their steam boilers and dairy production processes.
solution Many borehole and mains water supplies contain high levels of dissolved mineral salts. Previously due to the high chloride content of the borehole water, subsequent heating created a highly corrosive and unstable solution that was attacking stainless steel and reducing the life of pasteurization equipment. Salts also accumulated in steam boilers and must be routinely discharged along with a quantity of water to allow additional fresh water and treatment chemicals back into the boiler. The water that is discharged to drain contains a significant level of heat energy having been heated to boiling point for food production purposes. At 10 bar pressure the boiling point of water is 179.9oC and the water contains approx 27% of the total energy of the steam being produced. This water also contains quantities of costly water treatment chemicals added to prevent corrosion and sludge within the boiler. Reverse Osmosis (RO), a method of purifying water by membrane filtration, physically removes 96-98% of the dissolved solids present whilst also removing all pathogenic organisms, making the water ideal for use in steam boilers and food production.

Because RO treatment is a physical process similar to filtration, no chemicals are used and operating costs are relatively low. The principal benefit of RO treatment when used to treat water used for steam boilers is that by removing 96% to 98% of the dissolved salts present in the water, boiler blow-down i.e. the discharge of hot water will be reduced by approx 80%, providing significant energy savings.
benefit By introducing the RO treatment process, the quality of steam was improved with less energy required, reduced chemical treatment and maintenance costs, allowed the producer to use free borehole water not their mains supply.