Organic Carbon Generation Mechanisms in Main and Premise Distribution Systems

dc.contributor.authorMartin, Amanda Kristineen
dc.contributor.committeechairEdwards, Marc A.en
dc.contributor.committeememberPruden, Amyen
dc.contributor.committeememberFalkinham, Joseph O. IIIen
dc.contributor.departmentEnvironmental Sciences and Engineeringen
dc.date.accessioned2014-03-14T20:43:48Zen
dc.date.adate2012-11-02en
dc.date.available2014-03-14T20:43:48Zen
dc.date.issued2012-08-06en
dc.date.rdate2012-11-02en
dc.date.sdate2012-08-19en
dc.description.abstractAssimilable organic carbon (AOC) is a suspected contributor to growth of microbes, including pathogens, in plumbing systems. Two phases of research were completed to improve knowledge of AOC and other forms of organic carbon in premise plumbing. In the first phase, the AOC Standard Method 9217B was compared to a new luminescence-based AOC in terms of time, cost, convenience, and sources of error. The luminescence method was generally more accurate, as it better captured the peak growth of the test organisms. It was also less expensive and less time-consuming. A few approaches to improving the accuracy of the method and detect possible errors were also presented. In the second phase of research, the possibility of AOC generation in premise plumbing was reviewed and then tested in experiments. It has been hypothesized that removal of AOC entering distribution systems might be a viable control strategy for opportunistic premise plumbing pathogens (OPPPs), but if AOC was generated in premise plumbing systems this approach would be undermined. Possible sources of AOC creation in premise plumbing, which is herein termed "distribution system derived biodegradable organic carbon (DSD-BDOC)," include: leaching of organic matter from cross linked polyethylene (PEX) pipes, autotrophic oxidation of H2 generated from metal corrosion (e.g. sacrificial magnesium anode rods and iron pipes), rendering of humic substances more biodegradable by sorption to oxides such as Fe(OH)3, and accumulation of AOC on filters and sediments. The potential for various plumbing and pipe materials to generate AOC was compared in controlled simulated water heater experiments. Under the worst-case condition, generation up to 645 µg C/L was observed. IT was not possible to directly confirm the biodegradability of the generated organic carbon, and there were generally no correlations between suspected generation of organic carbon and either heterotrophic plate counts (HPC) or of bacterial 16S rRNA genes. DSD-BDOC was also explored in a simulated distribution system with two disinfectant types (chlorine and chloramine) and three pipe materials (PVC, cement, and iron). TOC increased with water age, probably due to leaching of organics from PVC and possibly the aforementioned DSD-BDOC due to autotrophic reactions of nitrifiers and iron-related bacteria. As before, relationships between the higher levels of organic carbon and either HPC or 16S were not observed.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-08192012-202007en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-08192012-202007/en
dc.identifier.urihttp://hdl.handle.net/10919/34648en
dc.publisherVirginia Techen
dc.relation.haspartMartin_AK_T_2012.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectdistribution system derived biodegradable dissolveen
dc.subjectopportunistic premise plumbing pathogensen
dc.subjectassimilable organic carbonen
dc.titleOrganic Carbon Generation Mechanisms in Main and Premise Distribution Systemsen
dc.typeThesisen
thesis.degree.disciplineEnvironmental Sciences and Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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