Dual-chamber microbial fuel cell with denitrifying biocathode for the treatment of cassava processing wastewater

Célula a combustível microbiana de dupla câmara com biocátodo desnitrificante para o tratamento de águas residuárias do processamento da mandioca

ABSTRACT

The aim of this study was to assess the feasibility of using cassava wastewater as a substrate for dual-chamber microbial fuel cells (MFCs) operating with denitrifying biocathodes. Two configurations related to the ion exchange membrane used were evaluated: one with an anion exchange membrane (MFC-A) and the other with a cation exchange membrane (MFC-C). Both bioreactors were operated in sequential batch mode. Furthermore, a low-cost platform based on Arduino technology was also proposed to enable continuous measurement and recording of voltage data from the MFCs. The highest voltage values were observed in the first days of MFC operation, with readings reaching approximately 350 mV (0.41 W·m ³) and gradually decreasing after 100 days of operation to 243 mV (0.20 W·m ³) and 125 mV (0.05 W·m ³) for the MFC-A and MFC-C, respectively (mean values for the last 20 days of operation). In both MFCs, the chemical oxygen demand reduction and nitrogen removal were over 98% after reactor stabilization, with no noticeable nitrite accumulation. The experimental results indicated superior performance when MFC was equipped with an anion exchange membrane. The results presented here demonstrate the feasibility of using cassava wastewater as a viable substrate for MFCs equipped with a denitrifying biocathode, allowing for efficient wastewater treatment and simultaneous electricity generation.

Keywords:
microbial fuel cell; autotrophic denitrifying biocathode; cassava processing wastewater; arduino differential voltmeter; ion exchange membrane