Sound Waves Kill Algae in Auckland Lake Sound waves are being used to kill algae at a water-supply lake in what is believed to be a first for the country. Algal blooms in summer can render water in the Lower Nihotupu Dam in west Auckland expensive to process or unusable. But a trial of ultrasonic technology, monitored and constantly adjusted by LG Sonic in the Netherlands, has shown promising results in keeping good water flowing from the dam. "We are not trying to get rid of the algae, just get it to levels that don't cause us problems," said Amy Holliday, water quality and environmental analyst for Watercare. "It gives that extra assurance that when people turn on the tap the water that they are drinking is safe. This technology is just adding another tool to our toolbox." Watercare believed it was the first time the technology had been used in New Zealand, she said. Lower Nihotupu Dam is one of three dams in the Waitakere Ranges Regional Park. It was costing $384,100 in capital expenditure and, if adopted, another $20,000 each year in running costs. The one-year trial started in December, and if it worked would save money at the water treatment plant, where less chemicals would be needed. An American company recouped the cost of deploying the technology in 1.8 years, Holliday said. So far it appeared to be a great success in New Zealand, with the blue-green algae count over summer 90 per cent less than the year before. The weather in Auckland had been cooler than most years though and so it was difficult to be sure just yet. Watercare dam technician Matt Hubrick said the cyanobacteria, also known as blue-green algae, thrived in warm water and formed slimy clumps that could become toxic to mammals. "The devices we're using not only monitor the water quality, the software program interprets the changing water quality in real time, so that changes can be made almost instantly. This means the onset of algal blooms can be predicted, then crippled and slowly killed." ‘’Ultrasound waves create a sound layer in the top layer of the water, which has a direct impact on the buoyancy of the algae’’ (Lisa Brand, CTO at LG Sonic). The algae cells will sink to the deeper and darker layers of the water column and are unable to photosynthesize, thus will eventually die due to a lack of light. The effects of our ultrasonic algae control products have been tested by various universities and are proven to be safe for fish, plants, zooplankton, and insects. About LG Sonic LG Sonic is a Dutch company with the mission to eliminate harmful chemicals in the environment. The company provides environmentally friendly solutions to effectively control algae in lakes, reservoirs, treatment plants, and other applications. Over the last decade, more than 10,000 LG Sonic products have been successfully installed in 52 different countries. For more information please visit www.lgsonic.com. This article is based on the article; ‘’Sound waves kill algae in Auckland lake’’ published at Stuff Environment. Author of this article is Simon Smith.
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