Impacts of various filtration media on wastewater treatment and bioelectric production in up-flow constructed wetland combined with microbial fuel cell (UCW-MFC)

Abstract

A successful design and operation of up-flow constructed wetlands combined with microbial fuel cell (UCW-MFC) were assessed for wastewater treatment and bioelectric production. One of the main aims of present study is also to investigate effect of various types of filtration media on wastewater treatment process and bioelectric production in UCW-MFC systems, and determine the most efficient media type in order to obtain higher wastewater treatment performance and generate higher bioelectric production. In the present experiment, UCW-MFC system with zeolite (clinoptilolite) as filtration media had higher treatment efficiency compared to other UCW-MFC systems with sand and volcanic cinder, and average COD, NH4+, NO3−, and TP removal efficiency were 92.1%, 93.2%, 81.1%, and 96.7%, respectively. This superior performance in the zeolite medium in the UCW-MFC system was due to its larger specific surface area, different framework structure, and more porous composition. On the other hand, the maximum average output voltage, power density, and Coulombic efficiency were also obtained for zeolite wetland system which 1.008 ± 0.14 V, 15.1 mWatt/m2, and 1.64%, respectively. In this respect, we found that the formation of electrogenic bacteria-zeolite media-graphite surface facilitate the degradation of organic substrate and increase electrogenic bacteria’ activities which are catalyzed during the electron flow from anode to the cathode. Thus, the results suggest that zeolite-based filtration media can be use for improving the treatment efficiency and bioelectric production in UCW-MFC.