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Chemosphere

Title:		Degradation of extracellular polymeric substances (EPS) extracted from activated sludge by low-concentration ozonation
Author(s):		Meng L; Xi J; Yeung M;
Address:		"Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, 100084 Beijing, China. Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, 100084 Beijing, China. Electronic address: xijinying@tsinghua.edu.cn"
Journal Title:		Chemosphere
Year:		2016
Volume:		20160114
Issue:
Page Number:		248 - 255
DOI:		10.1016/j.chemosphere.2015.12.060
ISSN/ISBN:		1879-1298 (Electronic) 0045-6535 (Linking)
Abstract:		"Reaction mechanisms between ozone and extracellular polymeric substances (EPS) can be the key of understanding the improvements in microbial aggregates properties by low-concentration ozonation. In this study, EPS are extracted from activated sludge and treated continuously by ozone gas at 270 +/- 41 ppm. The reaction between ozone and EPS was investigated by observation of EPS component concentrations, functional groups and molecular weight distributions using UV-Vis spectrometry, excitation-emission matrix fluorescence spectroscopy (EEM), high performance size-exclusion chromatography (HPSEC) and gas chromatography-mass spectrometry (GC-MS). In a 12-hour-ozonation experiment, significant ozone consumption was observed in the first 4 h and protein concentration in EPS solution was reduced by 30 +/- 12%. However, the polysaccharides concentration only had a slightly decrease at the end of the ozonation process. UV-Vis spectra and EEM spectra results suggest that ozone removed protein and fluorescent matters (SMP and tryptophan-like aromatic protein) rapidly by attacking specific amino acid residues on polypeptide chain. After ozonation, the molecular weight of polysaccharide and protein dropped by 4 orders of magnitude according to HPSEC results. TOC concentration of EPS solution was reduced by 13 +/- 2% after ozonation. The loss in TOC could be explained by the observation of volatile organic compounds such as carboxylic acids, aldehydes and ketones in the off-gas detected by GC-MS. The results in this study can provide a better understanding towards the mechanisms of improvements in activated sludge properties by ozonation"
Keywords:		"Biopolymers/*chemistry Chromatography, Gel Gas Chromatography-Mass Spectrometry Molecular Weight Oxidants/*chemistry Ozone/*chemistry Polysaccharides/chemistry Proteins/chemistry Sewage/*chemistry Spectrometry, Fluorescence/methods Extracellular polymeric;"
Notes:		"MedlineMeng, Lu Xi, Jinying Yeung, Marvin eng Research Support, Non-U.S. Gov't England 2016/01/15 Chemosphere. 2016 Mar; 147:248-55. doi: 10.1016/j.chemosphere.2015.12.060. Epub 2016 Jan 14"