Off-campus WSU users: To download campus access dissertations, please use the following link to log into our proxy server with your WSU access ID and password, then click the "Off-campus Download" button below.
Non-WSU users: Please talk to your librarian about requesting this thesis through interlibrary loan.
Access Type
WSU Access
Date of Award
January 2022
Degree Type
Thesis
Degree Name
M.S.
Department
Civil and Environmental Engineering
First Advisor
Shawn McElmurry
Abstract
COMPARING FLOW CYTOMETRY, FLOW IMPEDANCE CYTOMETRY, ADENOSINE TRIPHOSPHATE METHOD, AND HETEROTROPHIC PLATE COUNTS FOR QUANTIFICATION OF BACTERIA DURING DRINKING WATER TREATMENTby AMBICA SALWAN December 2022 Advisor: Dr. Shawn P McElmurry Major: Environmental and Sustainability Engineering Degree: Master of Science Bacteria are removed at multiple stages during drinking water treatment. While unit process removal of specific pathogens is studied, routine monitoring of bacterial levels in treatment plants is typically limited and performed by culturing heterotrophic and coliform bacteria. Heterotrophic plate count (HPCs) and total coliform count methods are time-consuming, laborious, and only quantify culturable bacteria. These methods do not provide information about the number of dead bacteria. Similarly, impedance flow cytometry (IFC) quantifies only intact cells. DNA-based methods, like qPCR, are organism specific and do not proved information about the number of viable cells. Fluorescence-based flow cytometry (FCM) has recently gained popularity as a fast, culture-independent technology that measures total and intact cells. For this study, we aimed to compare HPC, ATP, and IFC measurements with those made by FCM to better understand plant performance and evaluate the potential use of these technologies for real-time controls. With this aim, we evaluated samples 3 times per week for 13 weeks from multiple points along the treatment train in a surface water treatment plant. Samples were collected at 8 points during treatment: raw water entering the plant before and after initial chlorination, after flocculation, after sedimentation, after ozonation, after filtration, in reservoirs before pumping into the distribution system, and in finished water entering the distribution system. During this study, the primary disinfectant was altered and the impact on bacterial counts at each stage of treatment was quantified. Overall, a greater variation in intact cells across the treatment train was observed using FCM than via other forms of quantification, with the order (variation described as orders of magnitude) being FCM(~3)≈IFC(~2-3)>HPC(~2)> ATP(~1). On average, using FCM, the number of intact cells was found to increase 36 times greater from post-ozonation to post-filtration. The same trend was not observed in HPC culture results. Results suggest traditional methods for biological monitoring (i.e. HPCs) may overestimate the effectiveness of water treatment.
Recommended Citation
Salwan, Ambica, "Comparing Flow Cytometry, Flow Impedance Cytometry, Adenosine Triphosphate Method, And Heterotrophic Plate Counts For Quantification Of Bacteria During Drinking Water Treatment" (2022). Wayne State University Theses. 903.
https://digitalcommons.wayne.edu/oa_theses/903