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Deposition and disinfection of Escherichia coli O157:H7 on naturally occurring photoactive materials in a parallel plate chamber
Journal article   Open access   Peer reviewed

Deposition and disinfection of Escherichia coli O157:H7 on naturally occurring photoactive materials in a parallel plate chamber

Alicia A. Taylor, Indranil Chowdhury, Amy S. Gong, David M. Cwiertny and Sharon L. Walker
Environmental science--processes & impacts, v 16(2), pp 194-202
01 Feb 2014
PMID: 24362649
url
https://europepmc.org/articles/pmc4090035View
Accepted (AM)Open Access (License Unspecified) Open

Abstract

Chemistry Chemistry, Analytical Environmental Sciences Environmental Sciences & Ecology Life Sciences & Biomedicine Physical Sciences Science & Technology
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 efficiency 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 (alpha-Fe2O3) 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 alpha-Fe2O3 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 alpha-Fe2O3 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 alpha-Fe2O3). a 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.

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#6 Clean Water and Sanitation

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Collaboration types
Domestic collaboration
Web of Science research areas
Chemistry, Analytical
Environmental Sciences
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