The Lake County Nutrient Reduction Facility (NuRF)
Discharge from Lake Apopka is the single largest controllable source of pollution in Lake County. The NuRF utilizes off-line liquid alum injection to remove pollutants flowing out of Lake Apopka into the rest of the Harris Chain of Lakes. Alum was selected because of its reliability and history of successful use in many different water treatment applications.
The project was constructed adjacent to the Apopka-Beauclair Canal near the County Road 48 bridge and the St. Johns River Water Management District’s lock and dam facility. The difference in water level upstream and downstream of the lock and dam provides the ability to treat over 90% of average annual Lake Apopka discharge without the need for pumps.
The Florida Department of Environmental Protection provided $3.7 million for construction of the NuRF and first-year monitoring costs. The St. Johns River Water Management District provided use of the land on which the NuRF was constructed. The remaining $3.7 million for construction cost and approximately $1 million in annual operation and maintenance cost for the facility will be paid by the Lake County Water Authority.
Many companies submitted competitive bids for this project designed by Environmental Research and Design, Inc. Gibbs & Register, Inc., based in Winter Garden, Florida, was awarded the bid for the lowest price and proven capability. Gibbs & Register, Inc. has performed several restoration-oriented projects in the local area.
Construction and Operation
Once alum combines with pollutants in the water, it forms heavy snowflake-like particles called “floc” which sink to the bottom. To collect the floc, two 9-acre settling ponds were constructed. The alum floc will be pumped from the ponds using a remote control dredge to a centrifuge for dewatering. The dewatered floc can then be further dried for use in a variety of beneficial applications.
Because of its off-line design, the NuRF retains all of the target pollutants and alum by-products sending only clean water downstream. The process removes at least 67% of the target algae-feeding nutrients and provides for the achievement of lake management goals for Lakes Beauclair, Dora, Eustis and Griffin. Clearer water will allow more beneficial plant growth resulting in better fish habitat and less sediment resuspension.
Project construction began in October 2007 and the facility became operational on March 2, 2009. Improvements to the downstream lakes will depend on the amount of rainfall and discharge from Lake Apopka. Smaller lakes may see improvements within months during normal rainfall conditions. Many other restoration projects are underway which will provide benefits as well.