Water, water everywhere

Although the industry uses more water than any other in Australia, food manufacturers are learning how to save this precious resource.

Food manufacturers consume more than 240 billion litres of water each year, RMIT University senior lecturer in civil engineering, Dr Niranjali Jayasuriya.

Dr Jayasuriya said any business in Victoria that uses more than 10 million litres of water annually must prepare a water-saving plan.

Smaller businesses are exempt and although they may want to reduce their water use, often lack the expertise or the money to develop their own schemes.

With a PhD from Melbourne University in water resources, Dr Jayasuriya was eager to help when Whittlesea and Hume councils, along with the Plenty Food Group, asked if there were methods that small and medium-sized food-producing businesses could use to identify how best to save water.

A grant from the Smart Water Fund, established in 2002 by the State Government and Melbourne’s four water authorities, enabled Dr Jayasuriya and her research team to spend 12 months investigating the issue.

They contacted 18 food processing companies and finally reached agreement with eight – all varying in size, production volume and type of food – to visit their factories and see what was involved.

The RMIT team decided the first step would be to measure where the water was being consumed.

“With each firm, we installed a water-monitoring system called hydroshare, water loggers that measure the water usage throughout the day in five-minute intervals,” Dr Jayasuriya said.

“These were attached to the water meters but we also did a manual audit as well. We wanted to match the water usage shown on the hydroshare with what we found with the manual audit to identify where they used the water – how much went in the toilets and the office area, how much in the canteen, how much was consumed during production and so on.”

The one area where a company could not be asked to cut back on water was in the manufacture of the food products. But even here, by changing the sequence in which certain operations occurred, it was possible to make savings.

“Food companies use a lot of water for cleaning the machinery,” Dr Jayasuriya said. “So if you can re-sequence this stage of the operations water can be saved.

“For example, if a company is producing a fruit juice with a red colour, they have to wash the machinery afterwards so it does not affect the colour of the next batch. But if you start with a light coloured juice first then the machines do not need to be washed when the next batch is darker coloured.”

Back at RMIT, the researchers developed a software program and spreadsheet that any company could apply to its operations.

The solution turned out to be a simple tool kit that can be downloaded free from the web.

The kit works by first classifying a business according to the food product manufactured. It then establishes the relevant water performance benchmarks for that industry.

The user must monitor the company’s water bills, the size of the factory’s roof area (for connections to a rainwater tank), the number of water outlets such as taps, hoses, washing machines and so on, the size of any cooling towers, the average quantity of the product made each week, the percentage of water in the product, and how much water is used in cleaning the equipment.

The program then takes the user through a series of windows to determine how water is used in manufacturing, comparing the various processes with industry benchmarks and cross-checking the total volume consumed with billing data.

The company is then presented with a range of water-saving options – including using alternative sources such as rainwater – that meet the strict regulations involved in food manufacturing.

“Options can range from re-fitting water-saving devices in toilets and on taps to using rainwater for the toilets and for washing, or for hosing down outside pavements and washing the trucks used to transport the food, which is not permitted with mains water,” Dr Jayasuriya explained.

She aded that although the RMIT toolkit was developed specifically for food manufacturers, the way it presents information could be useful for other manufacturing businesses looking to cut water use.

— The Age

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