BIOLOGICAL AND PHYSICAL-CHEMICAL METHODS FOR TREATMENT OF SEMICONDUCTOR MANUFACTURING EFFLUENTS

Persistent Link:
http://hdl.handle.net/10150/195838
Title:
BIOLOGICAL AND PHYSICAL-CHEMICAL METHODS FOR TREATMENT OF SEMICONDUCTOR MANUFACTURING EFFLUENTS
Author:
Gamez Grijalva, Victor Manuel
Issue Date:
2009
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Semiconductor manufacturing is one of the most advancing, growing and evolving industries. The production of semiconductors presents several challenges, both technologically and environmentally. The amount and complexity of the chemical substances utilized in the manufacturing process has been growing exponentially, and new chemicals are often introduced to the process and the environment. Two steps of this process play a special important role in the introduction of new chemical and demand of natural resources: Chemical Mechanical Planarization (CMP) and Photolithography.Wastewaters from the semiconductor manufacturing are complex and have several chemicals in different concentrations. Heavy metals, acids, chelators, surfactants and other chemicals are found in semiconductor effluents. Part of the scope of this study is to evaluate and remediate wastewaters produced in semiconductor manufacturing.During the development of this project it was found that copper can be successfully removed and recovered from CMP wastewaters by the use of a sulfate reducing bioreactor and a crystallization reactor, promoting precipitation of copper sulfides on the surface of silica sand. High removal and recovery efficiencies were found as result of the study. Another finding include that citrate is a readily biodegradable compound which can be successfully utilized as electron donor for anaerobic processes such as methanogenesis and sulfate reductions. However other important chelator, like EDTA, can cause toxicity to these microorganisms and affect important biological processes. PFOS is an important chemical for the semiconductor industry; however, the physical and chemical properties make this compound persistent in the environment and bioaccumulative. New substitutes for PFOS were tested and evaluated for their environmental impact. It was found that perfluorination plays an important role in the chemical properties of PFOS and removal of this characteristic improves the environmental performance of the new substitutes. Evaluation of these new chemicals was also performed by simulation and modeling. The software utilized in this study identified properties like toxicity and octanol-water partition coefficient accurately. On the other hand biodegradability was poorly estimated and new models are suggested for evaluation of this property for compounds with characteristics similar to the ones studied here (specifically high fluorination).
Type:
text; Electronic Dissertation
Keywords:
Biodegradation; Copper; Perfluorooctanesulfonate; Semiconductor; Toxicity; Wastewater
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Environmental Engineering; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Sierra-Alvarez, Reyes
Committee Chair:
Sierra-Alvarez, Reyes

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleBIOLOGICAL AND PHYSICAL-CHEMICAL METHODS FOR TREATMENT OF SEMICONDUCTOR MANUFACTURING EFFLUENTSen_US
dc.creatorGamez Grijalva, Victor Manuelen_US
dc.contributor.authorGamez Grijalva, Victor Manuelen_US
dc.date.issued2009en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractSemiconductor manufacturing is one of the most advancing, growing and evolving industries. The production of semiconductors presents several challenges, both technologically and environmentally. The amount and complexity of the chemical substances utilized in the manufacturing process has been growing exponentially, and new chemicals are often introduced to the process and the environment. Two steps of this process play a special important role in the introduction of new chemical and demand of natural resources: Chemical Mechanical Planarization (CMP) and Photolithography.Wastewaters from the semiconductor manufacturing are complex and have several chemicals in different concentrations. Heavy metals, acids, chelators, surfactants and other chemicals are found in semiconductor effluents. Part of the scope of this study is to evaluate and remediate wastewaters produced in semiconductor manufacturing.During the development of this project it was found that copper can be successfully removed and recovered from CMP wastewaters by the use of a sulfate reducing bioreactor and a crystallization reactor, promoting precipitation of copper sulfides on the surface of silica sand. High removal and recovery efficiencies were found as result of the study. Another finding include that citrate is a readily biodegradable compound which can be successfully utilized as electron donor for anaerobic processes such as methanogenesis and sulfate reductions. However other important chelator, like EDTA, can cause toxicity to these microorganisms and affect important biological processes. PFOS is an important chemical for the semiconductor industry; however, the physical and chemical properties make this compound persistent in the environment and bioaccumulative. New substitutes for PFOS were tested and evaluated for their environmental impact. It was found that perfluorination plays an important role in the chemical properties of PFOS and removal of this characteristic improves the environmental performance of the new substitutes. Evaluation of these new chemicals was also performed by simulation and modeling. The software utilized in this study identified properties like toxicity and octanol-water partition coefficient accurately. On the other hand biodegradability was poorly estimated and new models are suggested for evaluation of this property for compounds with characteristics similar to the ones studied here (specifically high fluorination).en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectBiodegradationen_US
dc.subjectCopperen_US
dc.subjectPerfluorooctanesulfonateen_US
dc.subjectSemiconductoren_US
dc.subjectToxicityen_US
dc.subjectWastewateren_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineEnvironmental Engineeringen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorSierra-Alvarez, Reyesen_US
dc.contributor.chairSierra-Alvarez, Reyesen_US
dc.contributor.committeememberField, James Aen_US
dc.contributor.committeememberFarrell, James Aen_US
dc.contributor.committeememberShadman, Farhangen_US
dc.identifier.proquest10339en_US
dc.identifier.oclc659752116en_US
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