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Statistical Evaluation of the Factors causing Microbial Growth in Point-of-use Filters

Due to the lead spike and its related health concern in the DC area, Point-of-Use (POU) filters were installed at public schools to reduce lead concentrations in water. However, the installation of POU filter could possibly lead to the growth of bacteria inside the filters, which could lead to health concerns. Therefore, the potential effects of POU filters on microbial growth was investigated. To explore the cause of filter effects on microbial growth, a sampling campaign was carried out between July and December 2017 from 25 outlets within 5 elementary schools in the DC area. The applicability of flow cytometry results as a quantification method was validated and then used to quantify the biological growth. Our results revealed that the installation of POU filters may lead to nitrification and an increase in microbial growth. Along with the increase in microbial growth, the microorganism community "fingerprints" based on flow cytometry data showed that the installation of filter could also shift the community distribution of bacteria based on their morphology. This study serves as a preliminary study to investigate the mechanics of microbial colonization on POU filters. / Master of Science / Due to the lead spike and its related health concern in the DC area, Point-of-Use (POU) filters were installed at public schools to reduce lead concentrations in water. POU filters are usually installed at sinks and fountains and the Water Quality Association reported that 41% of American homes used POU filters by 2000. However, the installation of POU filter could possibly lead to the growth of bacteria inside the filters, which could lead to health concerns. Therefore, the potential effects of POU filters on microbial growth was investigated. To explore the cause of filter effects on microbial growth, a sampling campaign was carried out between July and December 2017 from 25 outlets within 5 elementary schools in the DC area. Flow cytometry is an optical technology that can measure and then analyze multiple physical characteristics of a single particle as it flows in a fluid stream. The applicability of flow cytometry results as a quantification method was validated and then used to quantify the biological growth. Our results revealed that the installation of POU filters may lead to nitrification and an increase in microbial growth. Along with the increase in microbial growth, the microorganism community “fingerprints” based on flow cytometry data showed that the installation of filter could also shift the community distribution of bacteria based on their morphology. This study serves as a preliminary study to investigate the mechanics of microbial colonization on POU filters.

Identiferoai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/83609
Date21 June 2018
CreatorsLin, Jie
ContributorsEnvironmental Sciences and Engineering, Wang, Zhiwu, Novak, John T., Dai, Dongjuan, Alfredo, Katherine
PublisherVirginia Tech
Source SetsVirginia Tech Theses and Dissertation
Detected LanguageEnglish
TypeThesis
FormatETD, application/pdf
RightsIn Copyright, http://rightsstatements.org/vocab/InC/1.0/

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