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Feasibility of nanoscale zero-valent iron (nZVI) for enhanced biological treatment of organic dyes

Author:
Liu, Jing, Liu, Airong, Wang, Wei, Li, Ruofan, Zhang, Wei-xian
Source:
Chemosphere 2019 pp. 124470
ISSN:
0045-6535
Subject:
biodegradability, biodegradation, biological treatment, chemical oxygen demand, decolorization, dyes, iron, membrane bioreactors, organic compounds, pH, redox potential, wastewater, wastewater treatment
Abstract:
Biodegradation of recalcitrant organic contaminants such as organic dyes is a fundamental challenge in wastewater treatment. We report herein the integration of nanoscale zero-valent iron (nZVI) with membrane bioreactors to achieve enhanced degradation of Congo red (CR) in wastewater. nZVI pretreatment converts the large and bio-recalcitrant CR molecules into smaller and more biodegradable organic compounds in continuous flow stirred tank reactors (CFSTR). A nZVI-bio system was experimented continuously for 52 d with a color removal efficiency of 99% and a reduction of chemical oxygen demand (COD) from 167 mg L−1 to less than 70 mg L−1. However, a conventional biotreatment system treating identical wastewater achieved color removal efficiency of just 30–70% and the COD reduction to 116 mg L−1. This suggests that integrated nZVI-bio system has potential for the treatment of recalcitrant organic dyes. On-line measurements of pH and redox potential in the CSFTR can be conveniently used to monitor and regulate treatment performance.
Agid:
6552591