Kinetic Study of an Industrial Waste Containing a Non-Biodegradable Fraction

Abstract

Abstract A study was undertaken which was primarily concerned with the use of batch tests to investigate the kinetic behaviour of a high strength industrial waste which contained a non-biodegradable fraction and to determine the kinetic parameters, maximum specific growth rate, umax, saturation constant, Ks, and cell yield, Y. Substrate for the experiments was obtained from the effluent of a forest products industry manufacturing millboard. Bacterial cells were obtained from a heterogeneous culture of organisms acclimatized to this substrate. Samples were withdrawn periodically and analysed, using organic carbon as a parameter, to study the organism growth and substrate removal patterns. Data analysis based on the Monod equation, u = umax S/(Ks + S), performed after values of specific growth rate, u, specific decay rate, kd, organism growth rate, dX/dt, and substrate removal rate, dS/dt, were obtained and the initial substrate concentrations were corrected for the ultimate non-biodegradable fraction, produced values for the desired kinetic parameters. The activation energy, E, calculated from the van’t Hoff-Arrhenius relationship was found to be 15,160 calories per mole. The corresponding Streeter-Phelps coefficient, Θ, was found to be 1.095. Observations indicated that the organic matter in the substrate was removed initially by adsorption, and then a first-order removal rate. At the higher temperatures the initial first-order removal rate was ultimately replaced by a second and slower first-order removal rate. This overall condition could be approximated by the use of a single second-order removal rate. This investigation indicated that relatively simple and economical batch shaker flask studies can be successfully used to determine kinetic parameters for a complex industrial waste undergoing biological degradation by a heterogeneous population of organisms.