The Effect Of Sludge Age On Biokinetic Coefficients

Utilities are employing short-sludge retention time (SRT) systems (≤2 days) for high-rate carbon removal. Short-SRT systems allows for energy optimization and resource recovery. For instance, the mechanism of carbon removal behind short-SRT systems is adsorption rather than oxidation. The adsorbed carbon can be put through anaerobic sludge digestion process to generate energy inform of biogas. Another advantage is that these systems leave a higher residual substrate level in their treated effluent compared to a long-SRT systems (≥5 days). The higher substrate level in the effluent is easily accessible for the downstream denitrification process. Currently, the reasons for a higher residual substrate is unexplained. The major objective of this paper is to compare biokinetic parameters of sludge at short and long SRTs to elucidate the differences. The biokinetic parameters of ordinary heterotrophic bacteria for short-SRT systems were identified to be higher than for the long-SRT systems. The maximum specific growth rate of 5 day–1and half saturation constant of 45 mgSS/L were identified. The information generated from this study will help in designing and modelling effluent quality of short-SRT systems.