IDI Celebrates First American High-rate DAF Installation
Infilco Degremont's First American DAF Installation is Producing High Quality, Low Turbidity Drinking Water for New York Residents
Richmond, Virginia -- Infilco Degremont's first U.S. potable water DAF system was commissioned October 24 at the Lake DeForest Water Treatment Plant in West Nyack, New York. Owned and operated by United Water New York, the 20 MGD plant is fed by a 1000-acre reservoir and provides 33% of Rockland County's drinking water.
In 2001 United Water began seeking an upgrade of the plant's aeration and sedimentation basins to a higher rate clarifier in order to improve overall water quality and taste, filter run times and plant efficiency. A pilot study of Infilco Degremont's AquaDAF™ Dissolved Air Flotation System was initiated in order to confirm operating criteria. Specifically, the owners were looking for efficient removal of solids, TOC, algae and color, with a consistent effluent turbidity of less than 1 NTU.
In mid-2002 evaluation of pilot results was completed and confirmed Infilco Degremont's AquaDAF system operated at exceptionally high loading rates of up to 16 gpm/ft². Even at such a high rate, the system produced minimal sludge and little coagulant was needed. Based on the pilot success a design-build team of Infilco Degremont, United Water and Black & Veatch Construction began full-scale design, and startup was quickly achieved by June 2003.
The first few months of operation have been successful. "We are more than pleased with AquaDAF's operating performance and clarified turbidity results," said Don Distante, an engineering manager for United Water. "Our customers are benefiting from better water quality, and our operators are at ease with the system." At the Lake DeForest plant, AquaDAF clarifiers are followed by mixed media filtration for filtered turbidity of less than 0.1 NTU. The system is producing three times lower turbidity than the plant's previous conventional treatment system while operating at a loading rate of 12 gpm/ft².
Infilco Degremont is the Suez Environment subsidiary specializing in water and wastewater treatment plants. With more than 3,000 employees working in over 70 countries, Infilco Degremont had 2002 revenues in excess of $900 million.
Lake Deforest Water Treatment Plant
AquaDAF Full-scale Results
Flow Rates: 9-10 MGD/per side (20 MGD total)
Loading Rates: 11-12.1 gpm/sq.ft.
Coagulant Dose: 25-28 PPM
Raw Turbidity: 3.5 to 6 NTU
Clarified Turbidity: 0.5 to 0.8 NTU
Filtered Turbidity: 0.04 to 0.1 NTU
Algae Removal: 92 to 96%
Click here to see how AquaDAF Dissolved Air Flotation works.