Semi-continuous measurement of oxygen demand in wastewater using biofilm-capacitance

Abstract

Bio-capacitive coulombs were tested for determination of the 5-day biochemical oxygen demand (BOD 5 ) using a dual-chamber microbial electrochemical cell (MxC) operated at charging (open circuit) and discharging (close circuit) conditions. For acetate medium, the cumulative coulombs charged in a capacitive biofilm anode (open circuit) were well correlated with BOD concentrations (R 2 ~ 0.9). The maximum detectable BOD 5 concentration with the biocapacitance MxC was close to 250 mg/L, and the cumulative coulombs were saturated for above the maximum BOD 5 concentration (Monod pattern). The bio-capacitance MxC sensor consistently showed high linearity between the cumulative coulombs and BOD 5 concentrations for domestic wastewater influent (R 2 = 0.93-0.99), despite of 1min charging. High correlation between the coulombs and BOD 5 concentration was also obtained for wastewater effluent at 1 min charging, which indicates that the bio-capacitance MxC sensor can semi-continuously measure BOD 5 concentration in wastewater at every 2 min (1min charging and 1min discharging).

Exploring the Biocapacitance in M3c-Based Biosensors for the Assessment of Microbial Activity and Organic Matter

“…Nevertheless, microbial activity determined with the ATP content also showed a remarkable significant regression coefficient with R 2 = 0.959 (p = 0.021), with a standard error of 13.34 ng cATP g − 1 gravel. Similar results have been reported by Sim et al (2018), who obtained R 2 > 0.9 for both acetate concentration and wastewater COD assessment with different charging times. Regarding continuous operation, Modin and Wilén (2012), and Yuan and Kim (2017), reported R 2 coefficients for acetate detection up to 0.99 in both cases.…”