Electro-conductivity of carbonaceous materials and their improvement in the purifying performance of the constructed wetland
BAI Shaoyuan1,, XU Manman1, QIAN Chaowen1, DENG Zhengui2, DING Yanli1,, 1.Key Laboratory of Environmental Pollution Control Theory and Technology in Guilin University of Technology, Guilin 541004, China 2.Guangxi Heng Sheng Water Environment Management Co. Ltd., Guilin 541004, China
Abstract:In this study, the effect of electro-conductive substrate on the electric field formations and organic removals in the constructed wetlands was investigated. Coke with low resistivity (0.8~2.5 Ω·m) and stability and conventional filler quartz sand were screened out to establish constructed wetland system (electro-conductive material coke constructed wetland: EC-CW, quartz sand constructed wetland: QS-CW), respectively. The effects of hydraulic retention times (6, 12, 18, 24 and 30 h) and influent COD (100, 300 and 500 mg·L?1) on the spontaneous electric field variation and organics degradation were studied. The results showed that the maximum electric potential difference (EPs) in EC-CW was 605~780 mV, and significantly higher than that in QS-CW (275~334 mV). COD removal rate by EC-CW was 16%~21% higher than that by QS-CW at high hydraulic and organic loadings. Cluster analysis of EPs distribution along the depth showed that there were better oxidation-reduction zones in the EC-CW than QS-CW, which was benefit for the degradation of organics and nitrates, and no significant improvement for TP and ${\rm{NH}}_4^ + $-N removal. Key words:microbial fuel cell-constructed wetlands/ in-situ electronic conductions/ organic pollutants degradation/ carbonaceous materials/ spontaneous electric field.
图1反应装置示意图及原理图 Figure1.Schematic diagram of reaction device and the illustration of working principle of CW in short circuit mode
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1.Key Laboratory of Environmental Pollution Control Theory and Technology in Guilin University of Technology, Guilin 541004, China 2.Guangxi Heng Sheng Water Environment Management Co. Ltd., Guilin 541004, China Received Date: 2020-12-28 Accepted Date: 2021-03-04 Available Online: 2021-05-23 Keywords:microbial fuel cell-constructed wetlands/ in-situ electronic conductions/ organic pollutants degradation/ carbonaceous materials/ spontaneous electric field Abstract:In this study, the effect of electro-conductive substrate on the electric field formations and organic removals in the constructed wetlands was investigated. Coke with low resistivity (0.8~2.5 Ω·m) and stability and conventional filler quartz sand were screened out to establish constructed wetland system (electro-conductive material coke constructed wetland: EC-CW, quartz sand constructed wetland: QS-CW), respectively. The effects of hydraulic retention times (6, 12, 18, 24 and 30 h) and influent COD (100, 300 and 500 mg·L?1) on the spontaneous electric field variation and organics degradation were studied. The results showed that the maximum electric potential difference (EPs) in EC-CW was 605~780 mV, and significantly higher than that in QS-CW (275~334 mV). COD removal rate by EC-CW was 16%~21% higher than that by QS-CW at high hydraulic and organic loadings. Cluster analysis of EPs distribution along the depth showed that there were better oxidation-reduction zones in the EC-CW than QS-CW, which was benefit for the degradation of organics and nitrates, and no significant improvement for TP and ${\rm{NH}}_4^ + $-N removal.