Browsing by Author "Xu, Bojun"
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- Microbial fuel cells coupled with open pond for wastewater treatment: is it viable?Xu, Bojun (Virginia Tech, 2015-06-21)Sediment microbial fuel cell (SMFC) is a special type of microbial fuel cells that can be deployed in a natural water body for energy production and contaminant removal. This MS project aims to explore whether it will be viable to apply SMFCs for wastewater treatment. Experimental SMFCs were studied in several configurations and operational modes for organic removal, nitrate reduction, and energy recovery. When treating an artificial secondary effluent for nitrate removal, the SMFC could remove 44% of the nitrate, higher than that without electricity generation. The enhanced removal was attributed to the supply of electrons to nitrate reduction in the aqueous phase through oxidizing the organics in the sediment. The lack of a proper separator between the anode and the cathode led to the failure of the SMFC when treating an artificial raw wastewater. Ion exchange membranes were incorporated into the MFCs that were installed in a lab-scale open water pond (150 L in volume). Such a system achieved 100% COD removal and more than 75% removal of ammonium nitrogen. However, denitrification remained as a challenge because of a lack of anoxic zone. To reduce the cost of the cathode catalysts, a polymer-based carbon cloth was investigated and exhibited better performance than bare carbon cloth. The results of this MS project have demonstrated that SMFCs in the absence of a proper separator cannot be applied for wastewater treatment. A membrane-based MFC system integrated with open pond may function as a wastewater treatment system, though nitrogen removal efficiency must be improved.
- Sediment microbial fuel cells for wastewater treatment: challenges and opportunitiesXu, Bojun; Ge, Zheng; He, Zhen (The Royal Society of Chemistry, 2015-03-27)Sediment microbial fuel cells (SMFCs) have been intensively investigated for the harvest of energy from natural sediment, but studies of their application for wastewater treatment mainly occurred in the past 2-3 years. SMFCs with simple structures can generate electrical energy while decontaminating wastewater. Most SMFCs used for wastewater treatment contain plants to mimic constructed wetlands. Both synthetic and real wastewaters have been used as substrates in SMFCs that achieved satisfactory performance in organic removal. SMFCs have also been scaled up from several litres to more than 150 L. To further develop this technology, identification of a suitable application niche is needed. Several challenges must be addressed, including more detailed analysis in energy production, consumption, and application, understanding the relationship between electricity generation and contaminant removal, selecting plants that will benefit electrode reactions, improving nutrients removal, and optimizing system configuration and operation. The potential applications of SMFCs for wastewater treatment include powering sensors to monitor treatment processes and enhancing the removal of specific contaminants by electricity generation.