Water Treatment: Fundamentals and Practical Implications of Bubble Formation

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dc.contributor.authorScardina, Robert P.en
dc.contributor.committeechairEdwards, Marc A.en
dc.contributor.committeememberLittle, John C.en
dc.contributor.committeememberKnocke, William R.en
dc.contributor.departmentEnvironmental Engineeringen
dc.date.accessioned2014-03-14T20:32:07Zen
dc.date.adate2000-02-26en
dc.date.available2014-03-14T20:32:07Zen
dc.date.issued2000-02-11en
dc.date.rdate2001-02-26en
dc.date.sdate2000-02-24en
dc.description.abstractWater utilities can experience problems from bubble formation during conventional treatment, including impaired particle settling, filter air binding, and measurement as false turbidity in filter effluent. Coagulation processes can cause supersaturation and bubble formation by converting bicarbonate alkalinity to carbon dioxide by acidification. A model was developed to predict the extent of bubble formation during coagulation which proved accurate, using an apparatus designed to physically measure the actual volume of bubble formation. Alum acted similar to hydrochloric acid for initializing bubble formation, and higher initial alkalinity, lower final solution pH, and increased mixing rate tended to increase bubble formation. Lastly, the protocol outlined in Standard Methods for predicting the degree of supersaturation was examined, and when compared to this work, the Standard Methods approach produces an error up to 16% for conditions found in water treatment. Air entrainment and ozonation are the key causes of dissolved gas supersaturation and eventual bubble formation in water treatment plants. Total dissolved gas probes (TDGP) are now available to directly measure supersaturation and have many advantages compared to conventional techniques. Bubble formation during coagulation-flocculation hindered particle sedimentation, producing settled turbidities double that of solutions without dissolved gases. In a filtration study, run time to one half of initial flow was decreased by 54% when the source water was increased from 0.1 to 0.2 atm supersaturation. Indeed, even at 0.05 atm supersaturation, run length was only 21 hours in solutions without added particulate matter. A case study confirmed that bubble formation can interfere with coagulation and filtration processes at conventional treatment plants.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-02242000-20530043en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-02242000-20530043/en
dc.identifier.urihttp://hdl.handle.net/10919/31332en
dc.publisherVirginia Techen
dc.relation.haspartChapter2.pdfen
dc.relation.haspartTitlePage.pdfen
dc.relation.haspartTitlePage.pdfen
dc.relation.haspartChapter1.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectnucleationen
dc.subjectbubbleen
dc.subjectwater treatmenten
dc.subjectcoagulationen
dc.subjectfiltrationen
dc.titleWater Treatment: Fundamentals and Practical Implications of Bubble Formationen
dc.typeThesisen
thesis.degree.disciplineEnvironmental Planningen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Engineeringen

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