Relative Effects of Water Chemistry on Aspects of Iron Corrosion

dc.contributor.authorZhang, Yanen
dc.contributor.committeechairEdwards, Marc A.en
dc.contributor.committeememberDietrich, Andrea M.en
dc.contributor.committeememberVikesland, Peter J.en
dc.contributor.departmentEnvironmental Engineeringen
dc.date.accessioned2014-03-14T20:47:04Zen
dc.date.adate2005-11-14en
dc.date.available2014-03-14T20:47:04Zen
dc.date.issued2005-09-13en
dc.date.rdate2006-11-14en
dc.date.sdate2005-10-26en
dc.description.abstractThe net present replacement value of all publicly and privately owned potable water pipes in the U.S. is on the order of $2.4 trillion dollars, and costs associated with deteriorating iron pipes is billions of dollars per year. Problems arising from iron corrosion include reduced lifetime of the material, scale buildup and energy loss, nonuniform corrosion and leaks, catastrophic failure, "red water," disinfectant loss and bacterial re-growth. Iron corrosion is a very complicated process and is affected by many factors. This research focused on the effect of disinfectant type, sulfate/chloride ratios, nitrate concentration, and magnesium hardness on iron corrosion. For the waters tested, chlorine better controlled red water and microbial activity in the bulk solution than chloramine. Changes in the sulfate/chloride ratio did not have a large effect on iron corrosion. High levels of nitrate increased the rate of chlorine decay as a result of free ammonia formation, and also increased the release of iron. Increased magnesium and zinc decreased the red water caused by high silicate. Microbiological activity is important in iron corrosion, and control of re-growth in water distribution systems is a major challenge for water utilities. A separate study examined the inter-relationship between iron corrosion and bacterial re-growth, with a special focus on the potential of iron pipe to serve as a source of phosphorus. Under some circumstances corroding iron and steel may serve as a source for all macronutrients necessary for bacterial re-growth including fixed carbon, fixed nitrogen and phosphorus. Conceptual models and experimental data illustrate that levels of phosphorus released from corroding iron are significant relative to that necessary to sustain high levels of biofilm bacteria. Consequently, it may be more difficult to limit re-growth on iron surfaces by limiting phosphorus in the bulk water.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-10262005-123347en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-10262005-123347/en
dc.identifier.urihttp://hdl.handle.net/10919/35501en
dc.publisherVirginia Techen
dc.relation.haspartthesis.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectnitrateen
dc.subjectdisinfectanten
dc.subjectred wateren
dc.subjectiron corrosionen
dc.subjectsulfate/ chloride ratioen
dc.titleRelative Effects of Water Chemistry on Aspects of Iron Corrosionen
dc.typeThesisen
thesis.degree.disciplineEnvironmental Planningen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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