Journal article
Deposition and disinfection of Escherichia coli O157:H7 on naturally occurring photoactive materials in a parallel plate chamber
Environmental science--processes & impacts, Vol.16(2), pp.194-202
02/2014
Handle:
https://hdl.handle.net/2376/107331
PMCID: PMC4090035
PMID: 24362649
Abstract
Dissolved organic matter in combination with iron oxides has been shown to facilitate photochemical disinfection through the production of reactive oxygen species (ROS) under UV and visible light. However, due to the extremely short lifetime of these radicals, the disinfection effciency is limited by the successful transport of ROS to bacterial surfaces. This study was designed to quantitatively investigate three collector surfaces with various potentials to produce ROS [bare quartz, hematite (α-Fe
2
O
3
) coated quartz, and Suwannee River humic acid (SRHA)] and the effects of extracellular polymeric substance (EPS) (full or partial coating) and solution chemistry (ionic strength, IS) on the interactions between bacteria and the ROS-producing substrates. With few exceptions, bacterial deposition studies in a parallel plate (PP) flow chamber have revealed increasing cell adhesion with IS. Furthermore, interactions between collector surfaces and cells can be explained by electrostatic forces, with negatively charged SRHA reducing and positively charged α-Fe
2
O
3
enhancing bacterial deposition significantly. Increased deposition was also observed with full EPS content, indicating the ability of EPS to facilitate interaction between cells and surfaces in the aquatic environment. In complementary disinfection studies conducted with simulated light, viability loss was observed for cells fully coated with EPS when attached to α-Fe
2
O
3
under all IS conditions. Based upon our prior study in which EPS was found to not inhibit hydroxyl radical activity toward bacteria, we proposed that EPS might therefore promote disinfection by facilitating cell attachment to ROS-producing surfaces where higher concentrations of ROS are expected at closer proximities to reactive substrates (
e.g.,
SRHA and α-Fe
2
O
3
). Our findings on the mechanism and controlling factors of cell interactions with photoactive substrates provide insight as to the role of ionic strength in photochemical disinfection processes.
Metrics
12 Record Views
Details
- Title
- Deposition and disinfection of Escherichia coli O157:H7 on naturally occurring photoactive materials in a parallel plate chamber
- Creators
- Alicia A Taylor - Department of Chemical and Environmental Engineering, University of California, Riverside, CA, USAIndranil Chowdhury - National Exposure Research Laboratory, United States Environmental Protection Agency, Athens, GA, USAAmy S Gong - Department of Chemical and Environmental Engineering, University of California, Riverside, CA, USADavid M Cwiertny - Department of Civil and Environmental Engineering, University of Iowa, Iowa City, IA, USASharon L Walker - Department of Chemical and Environmental Engineering, University of California, Riverside, CA, USA
- Publication Details
- Environmental science--processes & impacts, Vol.16(2), pp.194-202
- Academic Unit
- Civil and Environmental Engineering, Department of
- Identifiers
- 99900546999001842
- Language
- English
- Resource Type
- Journal article