Design and evaluation of an automated oxygen uptake rate measurement system

Abstract

The design and operating procedure for a newly developed automatic oxygen uptake rate (OUR) measurement apparatus is presented. This unit, with the aid of a microcomputer, is capable of collecting a volume of sample, aerating the sample, measuring the oxygen concentration at preselected times, and calculating the oxygen uptake rate on a routine basis. The OUR unit was evaluated using three different performance testing procedures. These were (1) a calibration and general performance test, (2) a long-term performance test, and (3) a detailed comparative performance test. The results of each of these tests are presented. The value and alternative uses of routine monitoring of OUR are discussed along the possible applications such as detection of toxic compounds entering the plant and adjustment of sludge return rates to match OUR values. Key words: oxygen uptake rate, activated sludge, microcomputer, process control, oxygen consumption.