Degradation of high concentration starch and biocathode autotrophic denitrification using photo microbial fuel cell

Abstract

In the study, a dual-chamber photo MFC was constructed with a photosynthetic bacteria consortium PB-Z and a heterotrophic nitrifier C16 as anode and cathode inoculant, respectively. The electron released from starch degradation in the anode by photosynthetic bacteria was transferred to the cathode, which was utilized by the nitrifying bacteria C16 to realize autotrophic denitrification. Lower resistance was more conducive to the electron transfer and pollutants removal. Comparing with natural light, continuous light greatly promoted starch degradation by the photosynthetic bacteria in the anode and the denitrification by the nitrifying bacteria in the cathode. Under continuous light and external resistance of 500 Ω, high concentration starch was degraded by photosynthetic bacteria PB-Z and the COD removal efficiency reached up to 88.45% within 12 d, and nitrate of 95.8% was removed within 4 d by autotrophic denitrification by heterotrophic nitrifier C16. The study provides some enlightenment and reference for the application of MFC in the field of wastewater treatment.

Keywords: High-concentration starch wastewater; Microbial fuel cell; No-carbon source nitrate wastewater; Photosynthetic bacteria.