News Release:
UNE helps Council at source of Armidale water
| Date 19/2/04 No 032/04 A 17-year-old collaboration between Armidale Dumaresq Council and the University of New England is helping to restrict the growth of blue-green algae in Malpas Dam, the source of Armidale's water supply. A simple but effective device designed, built and installed at the dam by UNE in 1987 has just undergone its annual service by University and Council technicians. Known as a "destratifier", the device consists of a 200-metre length of polythene pipe (60 mm in diameter) with 600 evenly-spaced nozzles through which compressed air can be pumped. The destratifier rests almost 20 metres below the surface, near the bottom of the dam. When in use during summer, rising air bubbles cause movement between the warm layer of water at the surface and the cooler water beneath. This circulation restricts not only the ability of blue-green algae to feed and thus to multiply, but also the release into the water of sedimentary iron and manganese that can cause colour and odour problems. The destratifier was designed specifically for Malpas Dam. Associate Professor Richard Faulkner, Head of Environmental Engineering at UNE, said the effectiveness of the device was partly to do with its length, which enables the production of a 200-metre-long "curtain" of bubbles along the centre of the dam. Depending on seasonal conditions, the destratifier is turned on for as few a seven or as many as 100 days each summer.
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Mr Mike Porter, Armidale Dumaresq Council's Process Control Manager, said the Council had commissioned UNE not only to design and install the device, but also to maintain it with an annual service. "The destratifier helps us to keep the algae at bay," Mr Porter said. "There is no absolute solution to the blue-green algae problem, but this device works as well in mitigating the problem as anything of its kind in the world. And, of course, Council's technologically-advanced water treatment works can handle anything that comes down the pipeline from the dam." Dr Faulkner and Mr Porter agreed that the destratifier was very effective in helping to minimise colour, taste and odour irregularities in the water supply. Mr Bruce Whan from Environmental Engineering at UNE designed the destratifier in 1987 and was one of the team carrying out the annual service earlier this week. His design allows the 200-metre pipe to be raised to the surface by a simple but ingenious system of buoyancy tanks in order for each of the nozzles to be inspected, and cleaned and repaired when necessary. Media contact: Jim Scanlan, Public Relations, UNE, Armidale (02) 6773 3049 or Associate Professor Richard Faulkner, Environmental Engineering, UNE, Armidale (02) 6773 3392. |
