Treatment of seafood industrial wastewater coupled with electricity production using air cathode microbial fuel cell under saline condition

Summary The present study investigated seafood industrial wastewater treatment with corresponding power generation in air cathode microbial fuel cell under saline condition (40 g/L). The results recorded total chemical oxygen demand) removal of 52 ± 1.8%, 64 ± 1.1%, 85 ± 1.2%, 89 ± 1.4%, and 76 ± 1.2% to the corresponding organic load (OL) of 0.5, 0.75, 1, 1.25, and 1.5 gCOD/L under saline condition. Soluble chemical oxygen demand reduction was in the range of 46% to 78% at OL of 0.5 to 1.5 gCOD/L. The maximum power density (530 ± 15 mW/m2) and coulombic efficiency (52 ± 2.4%) was procured at the OL of 1.25 and 0.5 gCOD/L, respectively. Total suspended solids removal was 74 ± 1.5% at OL of 1.25 gCOD/L and 64 ± 1.3% at OL 1.5 gCOD/L. Bacterial community analysis for anode region samples for OL 0.5 and 1 gCOD/L was extensively dominated by Bacillus (MN880233) with 75.8% and 55.8%, respectively. Interestingly at 1.25 gCOD/L OL, Rhodococcus (MN880237) was predominant (42.3%) strain in the anode region and recorded high power production under saline condition. Sludge samples subjected to phylogenetic analysis explored the dominance of Clostridium, Turicibacter, and Marinobacter at different OL from 0.5 to 1.5 gCOD/L. Bacterial community results at 1.25 gCOD/L of OL sludge samples revealed completely different strains of dominancy in the community. Marinobacter (53.3%), Ochrobactrum (19.3%), and Bacillus (8.1%). Thus, the phylogenetic analysis of the anodic and sludge samples clearly detailed the presence of halophilic bacterial strains with high potential to treat seafood processing industrial wastewater and excellent exoelectrogenic activity for power production. Treatment of seafood industrial wastewater in air cathode microbial fuel cell (ACMFC) under saline condition. Total chemical oxygen demand and soluble chemical oxygen demand removal was 89 ± 1.4% and 78 ± 1.5% at 1.25 gCOD/L OL. Maximum power density of 530 mW/m2 at 1.25 OL. Dominance of Rhodococcus, Ochrobactrum, Bacillus and Marinobacter in ACMFC. Air cathode microbial fuel cell (ACMFC) used in the study potentially treated saline seafood industrial wastewater with TCOD (89%), SCOD (74%) removal and corresponding energy production of (530 mW/m2) at optimized organic load (1.25 gCOD/L) under saline condition (4%). Rhodococcus as predominant (42.3%) strain in the anode region, Marinobacter (53.3%), Ochrobactrum (19.3%) and Bacillus (8.1%) in sludge region enhanced high power production in ACMFC at opt