Description
This paper discusses an effort by United Water New York (UWNY) to design/build the first high rate dissolved air flotation (DAF) system in the United States at its Lake DeForest Water Treatment Plant (LDF WTP). The reasons for the upgrade included: increase plant capacity from 10 mgd to 20 mgd;improve algae removal;capability for pH adjustment prior to coagulant addition (CO<sub>2</sub> was selected);improve filtered performance (lower turbidities and longer filter run times); and,lower disinfection byproducts (DBPs). LDF is the largest reservoir in a chain of reservoirs that comprise the HackensackRiver Watershed. It is a eutrophic lake that receives runoff from suburban fertilizedlawns, septic systems and inputs from streams and smaller lakes that are also eutrophic.Typical water quality ranges in LDF:Algae – up to 5,000 counts;TOC – 4 to 6 mg/L;color – up to 50+ units; and,low turbidity – 3 to 8 ntu.In addition to these treatment challenges, UWNY also needed to maximize microbialremoval/inactivation and minimize DBPs. Major improvements included: CO<sub>2</sub> feed system for pre-coagulation pH adjustment;48-inch in-line static mixer for improved chemical mixing;DAF Pretreatment – hydraulic flocculation;high-rate DAF system;supersaturated air addition;solids separation/DAF Float;residuals wasting/DAF effluent;AquaDAF recycle stream; and,6,000 sf pre-engineered building designed to match existing structures.The total cost for these improvements was $9 million. LDF overall performance is discussed along with chemical optimization, copper sulfate treatment event, aluminum breakthrough, and high filter turbidities. Includes table, figures.
Product Details
- Edition:
- Vol. – No.
- Published:
- 11/15/2004
- Number of Pages:
- 12
- File Size:
- 1 file
- Note:
- This product is unavailable in Ukraine, Russia, Belarus
