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A pilot study was conducted from September through mid-November 2003 to assess twotypes of dissolved air flotation (DAF) clarification processes, followed by filtration, andestablish design criteria for a proposed water treatment plant in Peekskill, New York. The DAF processes examined during this pilot study were conventional DAFtreatment and proprietary high rate DAF treatment (AquaDAF", licensed by InfilcoDegremont from Rictor Oy, Finland). This paper presents an overview of the pilot study,including details on the pilot facilities and criteria used to measure the performance of theprocess trains, and an evaluation of results.The conventional DAF process train included in-line static mixing and two-stageflocculation, followed by dissolved air flotation. The high rate DAF process trainincluded mechanical mixing and three-stage flocculation, followed by dissolved airflotation. Following dissolved air flotation, both process trains were connected to acommon set of filters, operated in parallel.Two loading rates were tested for each DAF process during the pilot study, 6 and 7.5gpm/sf for conventional DAF and 12 and 16 gpm/sf for high rate DAF. Various filterloading rates were also tested. Filters with typical depth media configurations were run at4, 5, and 6 gpm/sf. Filters with deep bed media configurations were run at 6 and 8gpm/sf.The pilot data confirmed that both the conventional DAF and high rate DAF processeswould provide high quality finished water (low filtered water turbidity and high particleremoval) while maintaining adequate filter run lengths. Filtered water turbidity wasconsistently below 0.1 NTU, log particle removal ranged between 1.1 and 2.8 foroptimized runs, and unit filter run volumes consistently exceeded the pilot goal of 7,500gal/sf. Additionally, concentrations of iron and manganese in the filtered water werefrequently undetectable and reliably below 0.02 mg/L and TOC removal ranged from41% - 58%. Includes tables, figures.

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Edition: Vol. - No. Published: 11/15/2004 Number of Pages: 11File Size: 1 file , 310 KB