Interpretation of Laboratory-Scale Waste Stabilization Pond Studies
The objective of this paper is to demonstrate the importance of choosing an appropriate mathematical model when analyzing the data from laboratory-scale studies of waste stabilization ponds. Two case studies are presented based on work by Thirumurthi and Nashashibi (1967) and Uhlmann et al (1983), both using semicontinuous methods of experimentation involving the addition of discrete volumes of feed at regular intervals. In both cases the authors have used mathematical models of continuous processes to analyse their results. This paper shows how semicontinuous models can be used in both studies, leading to significant differences in interpretation of the data; in the first case study this relates to the determination of rate constants and, in the second case study, to the determination of an appropriate model to describe hydraulic mixing. Each case study concludes with a discussion of the significance of the semicontinuous interpretation in the context of waste stabilization pond design.