Evaluation of electricity production from Fenton oxidation pretreated sludge using a two-chamber microbial fuel cell

摘要

This study evaluated electricity production from a two-chamber microbial fuel cell (MFC) coupled with sludge Fenton oxidation process. The total experimental period was divided into two stages. In the first stage, a series of batch studies were carried out to elucidate the parameters governing sludge Fenton process. The optimum conditions have been found as pH=3, H2O2 dosage=9.99 g/L and Fe2+ dosage=0.75 g/L. In the following stage, two MFCs, one MFC was filled with pretreated sludge supernatant (FSMFC) and the other MFC was filled with raw sludge supernatant (RSMFC), were operated to generate electricity. It was demonstrated that Fenton pretreated sludge showed significantly improvement in MFC electrical productivity. FSMFC reached a maximum power density of 8.15 w/m(3) at a current density of 18.05 A/m(3), while RSMFC reached the maximum power density of 0.45 w/m(3) at a current density of 1.09 A/m(3), much lower than FSMFC. The reduced inner resistance of 36.73 O in FSMFC, hence yielding higher maximum power density. And utilization of organic matter in FSMFC was much higher than that in RSMFC, the removal efficiencies of SCOD, protein and polysaccharide were 70.7%, 46.4% and 53.2%, respectively. On the other hand, samples of inoculation sludge and anodic biofilm were analyzed using the metagenome sequencing technique for microbial community analysis. At the phyla level, the total percentage of Proteobacteria, Bacteroidetes, Firmicutes, Acidobacteria and Chloroflexi of total sequences increased from 76.94% (inoculated sludge) to 92.09% (MFC biofilm), these phyla were most frequently detected in MFC. At the genus level, it suggested that the inoculation sludge was mainly dominated by Unclassified, while Comamonas, Burkholderia, Desulfovibrion Pseudomonas and Pseudoxanthomonas well-known electrogens were identified in anode biofilm.