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dc.contributor.authorKhanthongthip, Passkornen_US
dc.date.accessioned2014-03-14T21:10:24Z
dc.date.available2014-03-14T21:10:24Z
dc.date.issued2010-03-29en_US
dc.identifier.otheretd-04082010-011102en_US
dc.identifier.urihttp://hdl.handle.net/10919/37592
dc.description.abstractAn activated sludge system that incorporates a sidestream anaerobic bioreactor, called the Cannibal process, was the focus of this study. A prior study of this process (Novak et al., 2007) found that this system generated about 60% less solids than conventional activated sludge without any negative effects on the effluent quality. Although that study showed substantial solids reduction, questions remain concerning the specific mechanism(s) that account for the solids loss. In this study, the mechanisms that account for the loss of biological solids was the focus of the investigation. The first part of this study was conducted to evaluate those effects in terms of the role of iron in the influent wastewater and feeding patterns on the performance of the Cannibal system. It was found that the Cannibal system with high iron in the influent produced less biological solids than the system receiving low iron. The data also showed that the Cannibal system operated under fast feed (high substrate pressure) produced much less solids than the system with slow feed (low substrate pressure). The high substrate pressure was achieved by feeding the influent wastewater to the Cannibal system over a short time period so that the substrate concentration would initially peak and then decline as degradation occurred. This is called â fast feed.â For low substrate pressure, the influent was added slowly so the substrate concentration remained low at all times. This is called â slow feed.â Later, an attempt to increase substrate pressure in the slow feed Cannibal system was conducted by either manipulating the aeration patterns or adding a small reactor in front of the main reactor (selector). It was found that either interrupting aeration in the aerobic reactor or providing a small aerobic reactor in front of the main reactor resulted in an increase in solids reduction. The second part of this study was to investigate the mechanisms of floc destruction in the fast and the slow feed Cannnibal systems. It was found that higher accumulation of biopolymers (proteins and polysaccharides) occurred in the fast feed system and this was associated with a greater solids reduction in the fast than the slow feed system. In addition, more protein hydrolysis and more Fe(III)-reducing microorganism activity in the fast feed environment were found to be factors in higher solids reduction. The last part of this study was to investigate the structure of the Cannibal sludge flocs generated under the fast and the slow feed conditions. It was found that the readily biodegradable (1 kDa.) protein is larger in the flocs from the fast feed than the slow feed Cannibal system. This resulted in higher floc destruction in the fast feed condition.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartKhanthongthip_P_D_2010.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectfast feeden_US
dc.subjectextractionen_US
dc.subjectproteinsen_US
dc.subjectpolysaccharideen_US
dc.subjectactivated sludgeen_US
dc.subjectslow feeden_US
dc.subjectenzymeen_US
dc.subjectmicrobially reducible ironen_US
dc.titleThe Biological Sludge Reduction by anaerobic/aerobic cyclingen_US
dc.typeDissertationen_US
dc.contributor.departmentCivil Engineeringen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineCivil Engineeringen_US
dc.contributor.committeechairNovak, John T.en_US
dc.contributor.committeememberBerry, Duane F.en_US
dc.contributor.committeememberBoardman, Gregory D.en_US
dc.contributor.committeememberLittle, John C.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-04082010-011102/en_US
dc.date.sdate2010-04-08en_US
dc.date.rdate2010-04-15
dc.date.adate2010-04-15en_US


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