Relative Insignificance of Virus Inactivation during Aluminum Electrocoagulation of Saline Waters

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• 作者：Charan Tej Tanneru ; Jothikumar N. ; Vincent R. Hill ; Shankararaman Chellam
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：December 16, 2014
• 年：2014
• 卷：48
• 期：24
• 页码：14590-14598
• 全文大小：525K
• ISSN：1520-5851

文摘

Combined removal and inactivation of the MS2 bacteriophage from model saline (0鈥?00 mM NaCl) waters by electrochemical treatment using a sacrificial aluminum anode was evaluated. Both chemical and electrodissolution contributed to coagulant dosing since measured aluminum concentrations were statistically higher than purely electrochemical predictions using Faraday鈥檚 law. Electrocoagulation generated only small amounts of free chlorine in situ but effectively destabilized viruses and incorporated them into Al(OH)_3(s) flocs during electrolysis. Low chlorine concentrations combined with virus shielding and aggregation within flocs resulted in very slow disinfection rates necessitating extended flocculation/contact times to achieve significant log-inactivation. Therefore, the dominant virus control mechanism during aluminum electrocoagulation of saline waters is 鈥減hysical鈥?removal by uptake onto flocs rather than 鈥渃hemical鈥?inactivation by chlorine. Attenuated total reflectance鈥揊ourier transform infrared spectroscopy provided evidence for oxidative transformations of capsid proteins including formation of oxyacids, aldehydes, and ketones. Electrocoagulation significantly altered protein secondary structures decreasing peak areas associated with turns, bends, 伪-helices, 尾-structures, and random coils for inactivated viruses compared with the MS2 stock. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) measurements showed rapid initial RNA damage following a similar trend as plaque assay measurements of infectious viruses. However, ssRNA cleavage measured by qRT-PCR underestimated inactivation over longer durations. Although aluminum electrocoagulation of saline waters disorders virus capsids and damages RNA, inactivation occurs at a sufficiently low rate so as to only play a secondary role to floc-encapsulation during residence times typical of electrochemical treatment.