AWWA WQTC58840

The 75 MGD Little Falls Water Treatment Plant in Totowa, New Jersey, required processimprovements to enable it to meet the Stage 2 D/DBP regulations as well as other long term rawwater quality problems. The source water originates in forested watersheds, but also receivesnumerous wastewater discharges upstream from the plant intake. Because this is an urbanwatershed, the raw water quality can vary considerably from month to month, day to day, and attimes even hour to hour. Principal contaminants of concern are disinfection byproductprecursors, pathogenic organisms, turbidity, algae, taste and odor, organic compounds, iron andmanganese, and nutrients.The retrofit design was developed to maximize the utility of both existing and new treatmentfacilities within the limited site. A major change is the use of a compact ballasted flocculationsystem to replace the function of the existing sedimentation basins. This is the largest (120MGD) ballasted flocculation potable water plant in the United States. In addition, ozone will beapplied to meet the full range of oxidation and disinfection goals for the project and is followedby deep bed biological filtration.As part of the design scope of this upgrade, the Black & Veatch/Hatch Mott MacDonald teamdesigned, constructed, and operated a 0.2 mgd Actiflo pilot plant at 30 gpm/sq. ft. and as high as42 gpm/sq. ft. Additionally, the pilot facility was equipped with an ozone contactor andbiological filters.The paper discusses the successful optimization of the ballasted flocculation process for theremoval of turbidity with respect to polymer, microsand size, and coagulant. Demonstrationtesting was performed in 2001 and side-by-side comparison studies with the full-scale facilitywere performed in 2003. The evaluation determined that the pilot facility underestimatedturbidity removal and required greater polymer and coagulant doses. The pilot facility iscurrently being used to optimize the full-scale for economical operations and as an indicator forchanges in water quality that require modifications to plant operation. Includes tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/02/2003

Number of Pages:

11

File Size:

1 file , 1.1 MB