Time to rethink your water strategy?

11 February 2018

Strict regulations govern hygiene and washdown requirements in the food industry which makes water an important resource. However, increasing water and sewerage costs mean that more efficient water and wastewater management is now essential.

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The food industry needs to change how it sees water. Delivery of mains water costs £1 per cubic metre, and it typically costs twice as much to discharge the equivalent volume, meaning that reusing and recycling wastewater can save up to £3 per cubic metre.

While the name ‘wastewater’ implies it is unusable and worthless, wastewater can be a valuable resource. For example, wastewater from dairies and distilleries can be passed through an anaerobic bioreactor to produce biogas which can be returned to the grid or back to the facility to supply energy – up to 80% of the electrical needs of some instances. A second by-product, biomass, can also be repurposed as fuel, or used as land fertiliser on farms.

Companies looking to increase their profit, while generating positive publicity, should analyse the total cost and environmental impact of current water usage, and implement solutions to reduce consumption.

Alleviating concerns?
There is often reticence within the food and beverage industry to reuse and recycle water, due to the ‘fear factor’ around using treated wastewater to, for example, clean a tank between production runs. However, a greater understanding of efficient and effective wastewater treatment should alleviate any concerns and overcome objections.

In many cases, specific treatment is needed before wastewater can be reused. Water recovery systems involving filtration, reverse osmosis (RO) and clarification steps can prevent hundreds of thousands of litres of wastewater entering the sewage system, reducing initial water consumption and offering significant financial savings. Reject water from the RO system can be recovered in a separate process, with the permeate quality often significantly better than mains water.

This technology-driven approach to water reuse and recycling can have a positive impact on a balance sheet, but will first require a new way of thinking, and an investment in innovative water processing solutions to gain the benefits. The perceived ‘slow’ return on investment (ROI) can be a stumbling block. However, by looking at water treatment and recycling as a slightly longer term investment – generally achieving an ROI over two to four years – companies can safeguard their future water supplies and reduce their environmental impact.

Case study
High quality water is critical for whisky distilleries, where it is used to feed the boilers that produce the steam to drive the stills, as well as to dilute the raw spirits before being filled into casks. After being closed for over 90 years, the resurrected Annandale Distillery, Annan, Dumfries & Galloway, wanted to be as self-sufficient as possible when it came to water. With its own on-site borehole, the distillery required a water treatment solution to ensure consistently high quality, while avoiding the added cost of installing a mains supply. This was achieved using a RO plant, supplied by Veolia Water Technologies, which is capable of providing up to 1,000l of softened, demineralised water per hour.?

Impurities are concentrated into a waste stream – around 25% of the RO feed – providing about 550l/hr of the treated water for spirit reduction, plus around 200l/hr for boiler make-up water. To ensure reliable and efficient boiler operation, and to minimise fuel consumption, this make-up water is conditioned using a custom-formulated chemical which combines oxygen removal and pH control for corrosion prevention and scale inhibition. The waste stream is collected and treated by a second, smaller recovery RO system, reducing the discharge volume and raw borehole water abstraction by a further 125l/hr.

Ignoring water consumption is becoming more costly for food processors. Now is the time to look at and implement innovative technologies to ensure more efficient management of water consumption.