An ACTIFLO® pilot scale study was conducted to evaluate ballasted flocculation and
high-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 by
the Board of Public Utilities. The Nearman WTP treats raw water drawn from a horizontal collector well located on the
south bank of the Missouri River. This water is defined as groundwater under the
influence of surface water, and must therefore be treated in compliance with all surface
water treatment regulations. The water is treated using chlorine and chlorine dioxide
which creates a ferric chloride coagulant, another dose of alum or ferric coagulant is
added, flocculated, settled and filtered through dual media filters.
During the pilot study, following the ACTIFLO® process, the water was filtered through
three separate pilot filters using various anthracite sizes. The dual media filter, which
simulated 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 ACTIFLO
process including an emulsified anionic polymer (Calgon Pol-E-Z 675), the Ciba LT25
dry 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 the
ACTIFLO® process pilot study followed by a filtration study were as follows:
evaluate the finished water quality produced by the ACTIFLO® process followed
by high-rate, deep-bed monomedia filters at loading rates up to 8 gpm/sq ft and
the existing dual media filter at 6 gpm/sq ft.; evaluate the filterability of the ACTIFLO® process effluent through the three
filters using various anthracite media sizes;
evaluate water quality impacts when ACTIFLO® sand size is reduced from 135
microns to 114 microns; and,
analyze sand and water samples to determine if arsenic is binding to the
ACTIFLO® sand and possibly being released into the settled water.
Results from the thirty day ACTIFLO and filtration pilot trial showed that the Pol-E-Z
675 polymer produced lower filtered water turbidities and longer filter run times than the
LT25 and E-38 polymer. The monomedia filters achieved longer filter run times and
greater productivity than the dual media filter. The filtrate from the monomedia filters
did meet water quality standards. The sand size did not appear to affect filtered water
quality and the adsorption of arsenic onto the recycled sand from the ACTIFLO process
was not observed. Includes abstract only.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 660 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 2 |
| Published : | 11/01/2005 |
