Development and analysis of oxygen-sensing probes for in situ monitoring of unsaturated solid-state biodegradation...

Oxygen (O2) sensors have been developed for in situ measurement of O2 in high-solids degradation processes. The O2 sensor has been shown to withstand the corrosive environment of the biodegradation process with high humidity and temperatures exceeding 60 degrees C. Calibration tests prior to and after in situ operation showed the sensor to perform accurately and reproducibly after 71 days of in situ operation. A linear relationship between O2-sensor output and water vapor pressure was confirmed through calibration experiments. To compensate for the effect of water vapor pressure on O2-sensor measurements, O2 concentration was expressed on a dry air basis using the confirmed linear relationship. In situ O2-sensor output expressed on a dry air basis was found to follow trends of gas samples analyzed by gas chromatography with good agreement.