Aeration equipment for energy efficiency
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Aeration equipment for energy efficiency By Chris French |07-11-2016 Lower costs and increase efficiencies across applications with the right system. caused by fermenting wastewater from herbs such as chamomile, parsley, coriander and chervil. Now, two 7.5-kilowatt (kW) aerators consisting of a chopper pump and an ejector system aerate the sludge in the main 500,000-gallon lagoon and mix the wastewater. A separate inlet lagoon also benefits from a 5.5 kW aerator that points directly at the inlet pipe. Set up to work at night or whenever liquor strengths require it during Camstar’s 24-hour operation, the aerators have to be rugged and reliable for an installation in which up to 35,000 gallons of water can be processed per day. Roquette, where aerator systems have created energy savings of 30 percent If engineers want to prove to their customers they are providing the best possible long-term solutions, then they need to look further than mere conventional aeration, according to Soren Rasmussen, director of Landia Inc. “In fact, they may only have to pick up the bad odors emanating from an industrial plant to know that something somewhere isn’t right,” Rasmussen said. “A rotten egg smell of hydrogen sulfide that may be wafting its way up from a storage lagoon will almost certainly have developed — and quite quickly — from an anaerobic environment caused by dead particles falling to the floor because the oxygen transfer is not great enough for the type of sludge.” A study of aeration At Camstar Herbs, Landia solved just such a problem where, during the long harvest season from May to November, unpleasant odors were emanating from the lagoons at the 500-acre site, An aerator with chopper pump and ejector system provides simultaneous aerating and mixing. | All images courtesy of Landia Inc. “We’ve recently completed a similar installation for a guar gum producer in Texas,” said Rasmussen, “where sludge was settling out on the bottom of their effluent lagoon. The consultant had advised the owner that floating aerators were best and had adhered to the tried and tested next pag

textbook calculations — but the floating aerators could not reach the depths where the sludge was accumulating. The [submersible aerators], which recirculate sludge and inject air at the bottom of the lagoon, were able to resuspend the solids and provide the necessary aeration and mixing. “A food processor, dairy or chemical company might look at all the surface bubbles and initially be content with all the apparent aeration activity, but achieving optimal conditions for a tank or lagoon is not just about surface aeration, it is about in-depth mixing and aeration, too. We believe it is best...

Located in Keokuk on the Iowa/Illinois border, the heart of corn production country, Roquette America previously utilized floor-mounted air diffusers powered by large blowers and several surface mixers to try to aerate and mix its primary and secondary oxidation tanks. However, this standard industry practice meant constant cleaning and replacing of diffuser membranes. Since Roquette operates 24/7, the process could not be suspended to drain the tanks. This resulted in the substantial outlay of having to hire divers to enter the tanks and carry out maintenance. Rob Decker, senior project...

“A treatment plant we were working with just recently gave us figures they’d been advised to use for over 1,500 hp of mixing energy — specified by a consultant who’d gone no further than the old textbook approach. We questioned it and we were able to show that we could help provide better, more comprehensive mixing for just onefifth of the power. Installing aeration equipment requires serious thought for any plant wanting to drive towards becoming energy neutral.” Chris French is a freelance journalist who specializes in wastewater/biogas. Landia Inc. is a subsidiary of Landia A/S,...