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Turning Waste To Cash

From the Foundation for Research, Science and Technology
For immediate release


A simple-looking tube a little more than two metres long could help food processing industries reduce their energy costs - in some cases by about $12,000 a year. The Smart-Drain, developed by Lower Hutt engineer Rodger Kallu, uses hot wastewater to heat incoming fresh water, slashing companies' energy and heating costs. Mr Kallu, an expert in energy and bioprocess engineering, says the tube is fixed to the top end of a drain. A self-cleaning screen removes debris bigger than 16mm in diameter. Inside the main tube are smaller pipes, down which the hot wastewater is carried. But between these pipes is a cavity that allows cold water to flow through in the opposite direction, heating the water as it goes. For drains below ground level, a low-head pump is used to bring the drain water to the top of the tube. Mr Kallu says the hot water can heat the incoming water to 30-45C. "This will save companies huge sums because they won't have to preheat the water for their operations. The Smart-Drain will do it for them." Aquacare NZ executive director Judy Kallu says the average company could get a payback on the cost of installing the drain in about 18 months. She gives an example of a meatworks that uses gas. "It's an average, single-shift plant, working a 10 hour day, five day week, 50 weeks of the year. We believe they could save $12,240 a year. But each site is different." Variations can arise from whether the plant uses gas or electricity, the quantity and temperatures of the water going in and out, the type of plant and the production hours. The project to develop the drain was supported by Technology New Zealand, which invests in research into new products, processes or services. Aquacare specialises in innovative water and energy management products, and advises on disposal of process waste energy and water. The Smart-Drain can be made bigger or smaller depending on the size of plant. It is cheaper to build and install than conventional heat exchange equipment, when complex pre-screening is considered. "There are a lot of businesses now that have drains with hot water going out - such as laboratories or laundries - who need to heat incoming cold water," Ms Kallu says. "Businesses are just starting to wake up to the fact that they can turn their trade wastes into money savers." -ends-

Caption: Rodger Kallu: New drain "will save companies huge sums because they won't have to preheat the water for their operations".

Contact: * Rodger Kallu, technical director, Aquacare NZ Ltd, 29 Birdwood Rd, Waterloo, Lower Hutt. Ph: (04) 566-3639. Email: Website: * Philip Mowles, Technology New Zealand at the Foundation for Research, Science and Technology, Ph: (04) 498-7845 or 025 815-426. Website:

Prepared on behalf of the Foundation for Research, Science and Technology by ID Communications. Contact: Ian Carson (04) 477-2525,

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