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.”
Anaerobic Methane Potential from Sludges
Questions often arise as to how much residual biodegradable matter remains in sludges from biological processes after previous treatment has been completed. In one case, sludge samples were removed from two facultative lagoons. Tests were conducted to determine the methane potential remaining in the sludges and to determine if the sludges were suitable for land spreading. Samples of the sludge were transferred to respective reactions vessels of a Challenge AER-200 aerobic/anaerobic respirometer system. The respective reactors contained 20.5 and 22.7 g VSS. Gas production was measured over a period of 18 days. Methane production ranged from 120 mL in one sample to 160 in the second sample as shown in the Figure below. The gas production rate was high for only about 2 days and then leveled off to a rate of about 4 mL/day. The COD conversion equivalent of the produced gas was only about 0.3 to 0.4 g per sample, thereby representing VSS conversions of 1.47 and 1.76 %. The sludge was then deemed to be suitable for land application without further treatment. The benefit of using respirometers to measure methane production over long periods of time is illustrated well in this case.