Testimonials
“We have found the performance of the system to be quite satisfying and user friendly. We are currently running low level O2 uptake experiments and are impressed with the sensitivity of the instrument.”
“I have found the performance of the Challenge AER-200 to be unmatched. The precise measurement of oxygen consumption, homogenous mass transfer of test materials, and constant and consistent operating temperature have enabled me to obtain extremely accurate test results, particularly as compared to other respirometer systems. I find the Challenge system to be extremely user friendly.”
Oxygen Uptake of Soil and Compost Samples
The Challenge AER–200 aerobic/anaerobic respirometer is ideally suited to determine in–situ rates of oxygen uptake in soil or compost samples – as may occur in the upper layers of soil under natural atmospheric conditions or in mixed compost reactors. This objective is accomplished by using a double–column reactor configuration as illustrated in Figure A in which an internal porous column holds the sample within an outer column. The headspace gas is circulated around the soil or compost sample by using an internal air pump to avoid diffusion limits within the samle. Figure B shows an example of oxygen uptake measured by the respirometer configuration illustrated in Figure A (a Challenge AER–200 system with soil column). In this case, samples were collected at intervals along the length of an open–bay in–vessel system that was used to compost municipal sewage sludge. The tests showed that oxygen uptake rates declined as the distance along the bay increased, thereby indicating improved compost stability. Further testing revealed that adding moisture along the length of the vessel improved stabilization (Paletski and Young, Compost Science and Utilization, v. 21, pp. 102 – 109, 1995).