Treatment of fish market wastewater and energy production using halophiles in air cathode microbial fuel cell

The present study is aimed to treat the fish market wastewater coupled with electricity production using halophiles in microbial fuel cell (MFC) technology under saline condition (4.6%). Halophilic consortium obtained from desalination plant brine water was used in the lab scale air cathode microbial fuel cell (ACMFC) reactor equipped with carbon brush and carbon cloth as anode and cathode. ACMFC (260 mL capacity) was operated with fish market saline wastewater at different organic load (OL) from 0.41 to 2.01 g COD/L with 20 day HRT (Hydraulic Retention Time). Total chemical oxygen demand (TCOD) removal at OL 0.41, 0.82 and 1.21 g COD/L was 68%, 77% and 84% in ACMFC. Correspondingly, soluble chemical oxygen demand (SCOD) removal was 63%, 74% and 81% respectively. The optimized OL for the treatment of fish market wastewater was 1.62 g COD/ L, where the TCOD (90%), SCOD (88%), TSS (Total Suspended Solids) removal of 71% coupled with power generation of 902 mV (Power density 420 mW/m2, Current density 550 mA/m2) was recorded. Columbic efficiency at OL 0.41 g COD/L was 56% and declined at OL 0.82, 1.21, 1.62 and 2.01 g COD/L to 48%, 39%, 29% and 17%. Increment in OL to 2.01 g COD/L revealed decrease in TCOD (64%), SCOD (60%), TSS (45%) removal and energy production. The bacterial strains present in the halophilic consortium were Ochrobactrum, Marinobacter, Bacillus, Rhodococcus, Flavobacterium, Alicyclobacillus, Pseudomonas, Martelella, Stenotrophomonas, Xanthobacter, and Microbacterium. High dominance of Ochrobactrum, Marinobacter and Bacillus was observed at optimized OL of 1.62 g COD/L in ACMFC. Further research on pilot scale MFC lead the way to technology transfer for the treatment of wastewater with corresponding energy production in industrial sector.

Automated summary

The study aimed to use halophiles in microbial fuel cells to treat fish market wastewater and produce electricity, achieving optimized removal and energy production under specific organic load conditions.