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.”
Standardized OUR (SOUR) Fingerprint - Pulp Mill Organic Load
A pulp mill was interested in evaluating the impact of increasing organic loading rates on the performance of their activated sludge systems. In this case, the wastewater and biomass concentrations were varied to give food–to–micoorganism (F/M) ratios of 0.5:1, 1:1, and 1.5:1. Test temperaturewas 35C. Specific oxygen uptake rate (SOUR=OUR/M) curves – measured using a Challenge AER-200 respirometer system – show a high rate of oxidation of readily biodegradable organic constituents. One peak occurs within one hour of test initiation. A second peak occurs between one and four hours of contact for the 1:1 and 1.5:1 F/M ratios. This reaction occurs at the low F/M test conditions but is superimposed on the first high–rate peak of oxygen uptake.
At the higher F/M ratios, insufficient organisms are present initially to oxidize the wastewater at maximum rates but grow rapidly to complete the OUR reactions within four hours. The oxidation of readily biodegradable organic constituents is followed by a long tail of slowly degrading constituents. In this case, the SOUR curve for the 0.5:1 F/M ratio represents the basic fingerprint for this plant. The SOUR curves for the 1:1 and 1.5:1 F/M ratio indicate that the activated sludge process would require several hours more contact time to allow complete oxidation of the organic constituents of the wastewater. The fact that the OUR does not reach endogenous rates after 20 hours of contact indicates that the oxidation of organic wastewater constituents had not been completed.