AWWA WQTC62446

An ACTIFLO® pilot scale study was conducted to evaluate ballasted flocculation andhigh-rate, deep-bed monomedia filtration, in addition to evaluating dual media filtration at the Nearman WTP in Kansas City, Kansas. The Nearman WTP is owned and operated bythe Board of Public Utilities. The Nearman WTP treats raw water drawn from a horizontal collector well located on thesouth bank of the Missouri River. This water is defined as groundwater under theinfluence of surface water, and must therefore be treated in compliance with all surfacewater treatment regulations. The water is treated using chlorine and chlorine dioxidewhich creates a ferric chloride coagulant, another dose of alum or ferric coagulant isadded, flocculated, settled and filtered through dual media filters.During the pilot study, following the ACTIFLO® process, the water was filtered throughthree separate pilot filters using various anthracite sizes. The dual media filter, whichsimulated the full-scale filter, was loaded at a rate of 6 gpm/sq ft and the monomedia filters at a rate of 8 gpm/sq ft. Three different polymers were also tested in the ACTIFLOprocess including an emulsified anionic polymer (Calgon Pol-E-Z 675), the Ciba LT25dry polymer, and Ciba E38 polymer, which is an emulsified version of LT25. The same three polymers were also tested as filter aid during the study. The objectives of theACTIFLO® process pilot study followed by a filtration study were as follows:evaluate the finished water quality produced by the ACTIFLO® process followedby high-rate, deep-bed monomedia filters at loading rates up to 8 gpm/sq ft andthe existing dual media filter at 6 gpm/sq ft.; evaluate the filterability of the ACTIFLO® process effluent through the threefilters using various anthracite media sizes;evaluate water quality impacts when ACTIFLO® sand size is reduced from 135microns to 114 microns; and,analyze sand and water samples to determine if arsenic is binding to theACTIFLO® sand and possibly being released into the settled water.Results from the thirty day ACTIFLO and filtration pilot trial showed that the Pol-E-Z675 polymer produced lower filtered water turbidities and longer filter run times than theLT25 and E-38 polymer. The monomedia filters achieved longer filter run times andgreater productivity than the dual media filter. The filtrate from the monomedia filtersdid meet water quality standards. The sand size did not appear to affect filtered waterquality and the adsorption of arsenic onto the recycled sand from the ACTIFLO processwas not observed. Includes abstract only.

Product Details

Edition:

Vol. - No.

Published:

11/01/2005

Number of Pages:

2

File Size:

1 file , 660 KB