AWWA ACE95043

During the spring of 1994, CH2M Hill conducted treatability testing at the Catskill Aqueduct Water Treatment Plant (CAWTP). The testing was to verify treatment performance and to develop process design criteria for key treatment plant components such as flocculation, dissolved air flotation (DAF), and deep-bed monomedia filtration for the design of the Town of Yorktown (New York) CAWTP. DAF was chosen as the clarification process for the following reasons: it has been in removing solids prior to filtration in water of similar quality to the Catskill Aqueduct water; it is more effective than conventional sedimentation in removing low density particles such algae; it requires shorter detention times than conventional sedimentation, resulting in decreased area requirements; and DAF treatment plants typically use less coagulant chemicals than conventional treatment. CH2M Hill studied deep-bed monomedia filtration on the basis of the following historical findings: increased filtration loading rates, resulting in higher filter productivity than dual-media filters; increased particle removal more efficiently than dual-media filters; and increased flexibility to add granular activated carbon (GAC) to the filter bed if future regulations require increased organics removal. Treatability testing consisted of the following two steps: Step One: Bench-scale enhanced-coagulation testing helped define the chemical dosages and pH required to achieve enhanced coagulation, which was evaluated further during pilot testing; Step Two: Pilot-scale testing verified and optimized the process design parameters for the overall treatment process.

Product Details

Published:

01/01/1995

ISBN(s):

0898678331

Number of Pages:

30

File Size:

1 file , 740 KB