Winston Park: Phosphate and Ammonia Reduction
Amanda Quilen Ph.D. - Winston Park is a residential community in Coconut Creek, Florida. Winston Park Lake is 12.7 acres (5 hectares) and has a maximum depth of 32’ with an average depth of 19.5’. The lake experienced massive fish kills every fall due to a reduction in oxygen during fall turnover, so Vertex installed an aeration system consisting of six XL5™ AirStations powered by 3 Brookwood™ compressors totaling 2.25 hp; which produced 14 CFM of air at 19 PSI. This system is sized to turn the water over in the lake at a rate of 0.8 turnovers per day.
Results
Nutrients: The highest orthophosphate levels were observed at the sediment-water interface. These levels were reduced from 0.34 mg/L on July 15, 2009 to 0.01 mg/L on April 7, 2010, a 97% decline. Ammonia levels were also highest in the bottom waters, and were reduced 55% from 0.60 mg/L in July to 0.27 in April. 
Biological oxygen demand (BOD) improved steadily, decreasing to the background detection limit (2 mg/L) by October 23, 2009. This represents a 60% decline in BOD.
Oxygen transfer: On the morning of June 24, the day after the aerators were turned on full-time, oxygen concentrations averaged only 0.7 mg/L (225 kg of oxygen in the entire lake), with surface values topping out at only 1.75 mg/L. Near complete destratification of temperature was achieved by July 8, after 2 weeks of running the aerators fulltime.
Aeration startup considerations: The volume of anoxic water is important to consider when starting up an aeration system.
