Focusing on the process diagnosis of anaerobic fermentation by a novel sensor system combining microbial fuel cell, gas flow meter and pH meter

•A novel sensor system was established combining MFC, gas flow meter and pH meter.•Variations of sensor signals were more valuable for diagnosis of anaerobic process.•MFC exhibited compatible signal variations with pH and gas flow meters.•Transient responses of sensor signals were observed subject to disturbances.

Process diagnosis is essential to ensure anaerobic fermentation stable and efficient. Here, a novel sensor system combining microbial fuel cell (MFC), gas flow meter and pH meter was developed to evaluate its feasibility for probing the anaerobic process established on a model high-rate bioreactor. Repeated transient responses of electrical signal, proton concentration, and gas flow rate, were observed subject to external disturbances. The transient response lasted from <1 h to 6 h. In addition, MFC obtained compatible signal variations with other sensors, and biofilm MFC (MFCBiofilm) resulted in better agreements than control MFC (MFCControl). These results revealed that 1) the composite sensor system was capable to probe anaerobic process, suggesting a novel approach for process analysis and diagnosis of biogas or biohydrogen production; 2) the variations of sensor signals might provide more valuable information for process diagnosis than sensor signals themselves.

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