Review of BAC Filtration Modeling in Drinking Water Treatment - Activated Carbon for Water and Wastewater Treatment - page 327

11
Review of BAC Filtration Modeling in Drinking Water Treatment
Ferhan C ec en

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In drinking water treatment GAC filtration can remove natural organic matter
(NOM) and synthetic organic compounds (SOCs) as well as some nutrients and
inorganic substances. Traditionally, the primary aim of modeling in water treat-
ment is to predict the removal of NOM; relatively few models consider the removal
of nutrients and micropollutants.
The design of a GAC filter for water treatment is based on laboratory or pilot
studies. The type of activated carbon has to be selected, and the phase and the
optimum EBCT and filter bed height have to be determined. However, on the
laboratory-or pilot-scale only a limited number of configurations can be tested.
Therefore, the main advantage of developing GAC filtration models is the extra-
polation of results to full-scale applications. Modeling can also be used for mon-
itoring, development of operational strategies, and trend analysis [1].
In this chapter, some basic models are reviewed, mainly following the chron-
ological order. The aim of this chapter is not to provide a detailed account of
individual models, but to present the fundamental approaches adopted in drinking
water biofilter modeling. Extensive reviews are available in the literature providing
in-depth information on GAC/BAC filtration [2-5].
GAC/BAC modeling in water treatment bears many similarities to that in
wastewater treatment. Therefore, for insight into the main issues the reader is
advised to refer to the equations presented in Chapter 6.

11.1
Substrate Removal and Biofilm Formation

The major difference between GAC/BAC filters operated in wastewater and water
treatment is that substrate concentrations are very low in the latter. In
water treatment, the influent BDOC and AOC concentrations of a GAC/BAC filter
range mostly from 0.1 to 1.5mg L 1 and 10 to 150

gL 1 , respectively. For the
formation of a biofilm on the GAC surface, the AOC parameter is more crucial
than the BDOC, since the former reflects compounds that can be readily assimi-
lated, as discussed in Chapter 8. In the major part of GAC filtration studies, a

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