1. Development of an automated, multi-vessel respirometric system to evaluate decomposition of composting feedstocks.
- Author
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Dsouza, Ajwal, Kiselchuk, Connor, Lawson, Jamie A., Price, Gordon W., Dixon, Mike, and Graham, Thomas
- Subjects
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CARBON monoxide detectors , *CARBON dioxide , *COMPOSTING , *ORGANIC wastes , *STANDARD deviations - Abstract
Aerobic respirometry, which involves measuring the carbon dioxide (CO 2) evolved during decomposition, is an invaluable metric for evaluating biomass decomposability, characterising compost feedstocks, and studying decomposition dynamics over time. However, respirometric systems and CO 2 sampling methods can be expensive, operationally cumbersome, and produce temporally low-resolution data. This paper details the technical development and validation of an automated, multi-vessel respirometric system using off-the-shelf microcontrollers and miniature non-dispersive infrared (NDIR) CO 2 sensors to produce temporally high-resolution and accurate CO 2 data generated from decomposing biomass. The accuracy of the NDIR CO 2 sensors, as given by the cumulative CO 2 (g), was validated through an acetic acid-sodium bicarbonate reaction test. In this test, a mean cumulative CO 2 evolution of 0.99 g (n = 8) was measured with the sensors from an expected stoichiometric yield of 1 g CO 2 , with a standard deviation of ±0.137 g. The operation, reliability, and reproducibility of the system were tested through a series of biomass decomposition experiments. Through these experiments, an airflow rate of 0.25 L min−1 was found to be most effective at preventing the excessive drying of biomass at an initial moisture content of 50%. The system sensed, per 5-s sampling event, a peak CO 2 concentration of ∼28,000 ppm at a temperature of 35 °C, which resulted in the largest mean cumulative CO 2 evolution of 27.93 g from 200 g dry biomass. As indicated by the CO 2 curves, the system can produce reliable and high-resolution CO 2 datasets on an individual vessel basis, making it a useful tool for respirometric studies. • An aerobic respirometric system with high-resolution CO 2 sampling was developed. • The reproducibility of the data in organic matter decomposition trials was high. • Accuracy of the CO 2 sensors was shown through acetic acid-sodium bicarbonate test. • The system produced reliable CO 2 data for aerobic decomposition of organic waste. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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