Enhanced dewatering of excess activated sludge through decomposing its extracellular polymeric substances by a Fe@Fe2O3-based composite conditioner.

Bioresour Technol

CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China. Electronic address:

Published: October 2016

Efficient sludge dewatering methods are highly desired by municipal wastewater treatment plants. In this study, Fe@Fe2O3 nanomaterial, combined with polydiallyldimethylammonium chloride (PDMDAAC) and H2SO4, was used for sludge dewatering. This composite conditioner exhibited an excellent dewatering capability. By using uniform design, the optimized dosages of Fe@Fe2O3, H2SO4 and PDMDAAC were determined to be 40, 136 and 4.8mg/gDS (dry solids), respectively. The moisture content of sludge cake decreased from 78.1% to 64.8%, and the capillary suction time from 56 to 21s. The sludge extracellular polymeric substances (EPS) were decomposed, resulting in greater conversion of the bound water into free water and the release of free water. The electron spin resonance results show that the molecular oxygen activation process induced by Fe@Fe2O3 produced hydroxyl radicals, which were mainly responsible for the EPS decomposition. In this way, an efficient composite conditioner for enhancing sludge dewatering was developed.

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http://dx.doi.org/10.1016/j.biortech.2016.06.139DOI Listing

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