Promoting the bio-cathode formation of a constructed wetland-microbial fuel cell by using powder activated carbon modified alum sludge in anode chamber

Abstract

Abstract MFC centered hybrid technologies have attracted attention during the last few years due to their compatibility and dual advantages of energy recovery and wastewater treatment. In this study, a MFC was integrated into a dewatered alum sludge (DAS)- based vertical upflow constructed wetland (CW). Powder activate carbon (PAC) was used in the anode area in varied percentage with DAS to explore its influences on the performance of the CW-MFC system. The trial has demonstrated that the inclusion of PAC improved the removal efficiencies of COD, TN and RP. More significantly, increasing the proportion of PAC from 2% to 10% can significantly enhance the maximum power densities from 36.58 mW/m 2 to 87.79 mW/m 2 . The induced favorable environment for bio-cathode formation might be the main reason for this improvement since the content of total extracellular polymeric substances (TEPS) of the substrate in the cathode area almost doubled (from 44.59 μg/g wet sludge to 87.70 μg/g wet sludge) as the percentage of PAC increased to 10%. This work provides another potential usage of PAC in CW-MFCs with a higher wastewater treatment efficiency and energy recovery.

Key findings

• ▸The inclusion of PAC improved removal efficiencies of COD, TN, and RP.
• ▸Increasing PAC proportion from 2% to 10% enhanced maximum power densities from 36.58 mW/m² to 87.79 mW/m².
• ▸Bio-cathode formation was induced by PAC, increasing total extracellular polymeric substances (TEPS) in the cathode area.

Keywords

Identifiers

DOI

10.1038/srep26514

Journal

Scientific Reports

Year

2016