17 otterbine.com TOP 10 REASONS FOR AERATION: 1. Algae and Aquatic Weed Control 2. Odor Reduction 3. Reduction/Elimination of Chemicals 4. Phosphorus Reduction 5. Elimination of Fish Kills 6. Oxidation of Iron and Heavy Metals 7. Mosquito Breeding Deterrent 8. Beneficial to Aquatic Animal Life & Ecosystem 9. Prolongs the Life of the Pond/Lake 10. Public Safety; Aeration Prevents Diseases Associated with Stagnant Water The scientific measure of an aerator’s capability to supply a lake with oxygen is its “Oxygen Transfer Rate” (OTR) as defined by The American Society of Civil Engineers. The gold standard for the measure of how much oxygen an aeration system transfers is the ASCE “Measurement of Oxygen Transfer in Clean Water.” Any manufacturer that is serious about helping its customers keep the aquatic ecosystem balanced and clean will happily provide you with oxygen transfer tests performed by an independent third party. Otterbine’s systems are tested for OTR by the University of Minnesota and Gerry Shell Environmental Labs; these test results can be found at www.otterbine.com. Be sure to ask for a manufacturer’s test results when in the market for an aerator. Aeration provides a multitude of benefits to a lake or pond. The primary benefit of any aeration system is to add dissolved oxygen to the water. Aeration supports aerobic digestion and oxidative processes. Aerobic digestion is where naturally forming bacteria consume or biodegrade organic material in the lake. We speak of oxidation primarily in that oxygen attaches to phosphorus in the water and converts it to an insoluble form, unavailable to plants as a nutrient. One gram of phosphorus grows one hundred grams of algae. Surface spray and diffused aeration are the most common type of aerators. Surface spray aerators throw water droplets through the air. The droplets trap atmospheric oxygen molecules and fall to the surface releasing “dissolved oxygen” (DO) into the water. The Otterbine High Volume surface spray aerator adds over 3lbs (1.5kg) of oxygen to the water per horsepower hour regardless of depth. Independent tests indicate that surface spray units add 2 mg/l of DO to the water at depths of 12ft (3.6m). Diffused aeration is a process where air is driven down a tube and released through a diffuser at the bottom of the basin. The air bubbles are slowly “absorbed” by the water as they rise to the surface. Air bubbles rise to the surface at 1ft (30cm) per second; meaning that diffuser OTR increases with depth. A diffused aerator will transfer only 1.59lbs of oxygen per horsepower hour in 8ft (2.4m) of water, while it will transfer up to 2.72lbs (1.23kg) of oxygen per horsepower hour in 14 ft (4.2m) of depth. Our 1HP High Volume and Sunburst aerators have a higher OTR than a 1HP diffuser system at depths of 8ft -14ft (or 2.4m - 4.2m.) Call the experts at Otterbine to assist you in selecting the right system for your application! Why the Science of Water Management is Critical Here are the results of a High Volume aerator after one month in operation.