Modelling of Escherichia coli removal by a low-cost combined drinking water treatment system
Date
2020-08
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
IWA Publishing
Abstract
ENGLISH ABSTRACT: This work presents mathematical modelling of Escherichia coli (E. coli) removal by a multi-barrier
point-of-use drinking water system. The modelled system is a combination of three treatment stages:
filtration by geotextile fabric followed by filtration and disinfection by silver-coated ceramic granular
media (SCCGM) then granular activated carbon (GAC) filtration. The presented models accounted for
removal mechanisms by each treatment stage. E. coli was modelled as a microbial particle. E. coli
inactivation by SCCGM was modelled using the Chick’s, Chick-Watson, Collins-Selleck and complete
mix system bacterial inactivation kinetic models, which were considered adequately representative
for describing the removal. Geotextile removal was modelled using colloidal filtration theory (CFT) for
hydrosol deposition in fibrous media. The filtration removal contributions by the SCCGM and GAC
were modelled using CFT for removal of colloidal particles by granular media. The model results
showed that inactivation by silver in the SCCGM was the main bacterial removal mechanism.
Geotextile and GAC also depicted appreciable removals. The theoretical modelling approach used is
important for design and optimization of the multi-barrier system and can support future research in
terms of material combinations, system costs, etc. Collector diameter, particle size, filtration velocity
and contact time were identified as critical parameters for E. coli removal efficiency.
Description
CITATION: Siwila, Stephen & Brink, Isobel C. 2020. Modelling of Escherichia coli removal by a low-cost combined drinking water treatment system. Water Supply, 20(5):1757–1775, doi:10.2166/ws.2020.084.
The original publication is available at: https://iwaponline.com
The original publication is available at: https://iwaponline.com
Keywords
Drinking water -- Purification, Colloidal filtration theory, Escherichia coli, Colloids, Water-supply engineering
Citation
Siwila, Stephen & Brink, Isobel C. 2020. Modelling of Escherichia coli removal by a low-cost combined drinking water treatment system. Water Supply, 20(5):1757–1775, doi:10.2166/ws.2020.084