Fighting contaminants in ponds and lakes with harsh chemicals can be dangerous, expensive and ineffective. Yet, the alternative -- aeration equipment -- can be too expensive to be cost-effective. Windmill-driven aeration systems can offer an alternative in some cases.
Windmill-driven aeration has been widely used in agricultural and recreational bodies of water due to its low capital cost and energy freedom. It is now becoming increasingly popular in municipal applications.
In Attica, NY, the water department caught onto wind power almost nine years ago. The 8.5-acre reservoir there, which holds approximately 50 million gallons of water, was contaminated with an influx of manganese and iron during the spring and autumn water turnovers.
“The condition was worst during the fall months when turnover would stir up iron and manganese that naturally occur in the reservoir,” said Brian Krawczyk, Chief Operator at the Attica Water Plant. “But when there was high manganese and iron content and we treated the water with chlorine, we would get red water problems and constant turbidity (suspended particles).”
The water treatment plant had used copper sulfate at the reservoir as an algaecide until a few years ago when the Department of Environmental Conservation issued new regulations on its application due to potentially toxic effects on fish, swimmers and the surrounding habitat.
“We did quite a bit of exploration on the Net, and aeration appeared to be the best solution,” Krawczyk said.
“In the process of researching aeration I came across the Koenders Windmill web site (the parent company of Superior Windmills, Regina, SK Canada),” Krawczyk said. “The wind power aeration solution has made us think differently.”
Krawczyk said the simplicity and efficiency of the windmill aeration systems were impressive. The company’s windmills were simple to construct and self-install, had relatively few parts, required little maintenance and required no electric power. The logistics considerations were not an issue, since the system is completely self-contained and ideal for remote locations.
The windmill keeps the water fresh because it pulls water down from the top, then it sweeps it across the bottom and pushes it up as a column of air. The effect is similar to turnover that is occurring at all times, keeping the water oxygenated.
There were two important considerations before making a final decision on the windmill – height and footprint.
“The reservoir is located in a wooded area that is sheltered by trees,” Krawczyk said. “There are not a lot of clearings. We had to keep the windmills at a relatively low height (12 feet) so that we could catch the air currents as they move across the water. Even though the reservoir is located in a bowl and there is not a whole lot of air moving in the area, just a relatively light breeze will keep the windmills spinning.”
The other problem was that the reservoir is contained by an earthen dam that is fairly narrow, so the windmill must have a relatively small footprint. The bigger the windmill tower, the bigger the footprint, so the 12-foot tower was a good solution for both footprint and height.
The Attica water department purchased five windmill aeration systems. Three were installed at the primary reservoir, and one for standby. The fifth windmill was eventually disassembled and converted to a water wheel that continuously flows and aerates water at a secondary reservoir.
One of the world’s leading manufacturers of Windmill Aeration Systems, Superior Windmill offers models from 12 to 20 feet in height with hub and compressor preinstalled at the factory for ease of installation. Depending on the model selected, volumes of air flow produced range from 1.5 cfm to 13.0 cfm with winds of 9 mph.
For more information, visit the Superior Windmill Inc. website at www.superiorwindmill.com.WW
About the Author: Ed Sullivan is a writer on technology based in Hermosa Beach, Calif
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