MFC-based biosensors for real-time monitoring BOD and Toxicity in paraquat and pesticide-contaminated wastewater.

Abstract

Monitoring water quality is crucial for ecosystem preservation and public health in Pakistan, where agricultural/chemical contamination is diminishing clean water resources. This research aimed to develop long-term, reusable, and cost-effective MFC-based biosensors for monitoring BOD and toxicity in paraquat, pesticide-contaminated wastewater. Two double-chamber MFCs were fabricated with a 250 mL working volume, a Nafion membrane, and carbon felt electrodes, inoculated with pesticide-contaminated soil (PMFC) and pesticide-contaminated soil plus anaerobic sludge (PSMFC). Both biosensors reached a voltage of 400 ± 10 mV after 48 h, which was enhanced to 600 ± 25 mV with a 200 mV solar input during the enrichment phase. During stable power generation, PMFC and PSMFC achieved current outputs of 0.024 mA and 0.014 mA, respectively, and power densities of 225.49 mWm -2 and 50.06 mWm -2 . PMFC (R 2 0.9343) showed a stronger linear correlation between BOD levels (10-70 mgL -1 ) and voltage than PSMFC (R 2 0.7673). Voltage initially increased at paraquat concentrations of 1-10 mgL -1 but decreased at 50-100 mgL -1 due to biofilm inhibition. BOD measurements by PMFC closely matched conventional BOD₅ results, with a mean relative error of 7.03 %, highlighting its superior sensing performance with a 40-min response time during real-time monitoring.

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Identifiers

DOI

10.1016/j.bioelechem.2025.109210

PubMed

41453318

Journal

Bioelectrochemistry (Amsterdam, Netherlands)

Year

2026