Green Technology Water Treatment System Protects Nearby Wetlands

November 2012, Vol. 67, No. 11
The discharge water is then cleaned even further by running it over a flow treatment trench

(More at Florida DOT Approves Project Switch To Slide Rail) Because of the nearby federally-protected wetlands, all discharge and drainage water from dewatering were monitored closely by the Florida’s Department of Environmental Protection , the federal Environmental Protection Agency and the local Southwest Florida Water Management District.

In order to assure that the nephelometric turbidity unit (NTU) levels of the discharge water were kept well below regulated threshold, project subcontractor Haleakala Construction recruited Florida Dewatering to assist in cleaning the water.

Florida Dewatering is employing a green technology system of pumping the dirty jobsite discharge water through an Efficiency Production Silt-Separator Sediment Tank and a flow treatment trench or “floc” trench. The combination system filters out large and fine sediment in the discharge water, bringing its NTU down from over 800 to just 1.5 NTU.

As discharge water slowly flows through a Silt-Separator Sediment Tank, solids and silt settle to the bottom of a series of six baffles with removal baskets.

“Florida Dewatering’s Bob Davis’ efforts were critical as we worked through a heavy ‘wet area’ between State Road 54 to State Road 56 in Wesley Chapel,” said Haleakala Project Foreman George Carillo.

“And, we worked straight through (Florida’s) rainy season. Any problems with the discharge water going into the wetlands, and the environmental authorities could shut the project down which happened last year to another contractor working two miles away,” Carillo explained.