| There are a number of physical, chemical and biological processes that may affect the concentration of a chemical in an aquatic system. Of all these mechanisms, biodegradation is the most important because it can mineralize toxic pollutants and render them harmless. Experiments have been conducted using an electrolytic respirometer to collect oxygen uptake data of 56 toxic compounds. Biokinetic parameters; maximum specific rate constant, {dollar}musb{lcub}rm m{rcub}{dollar}, half saturation constant, K{dollar}sb{lcub}rm s{rcub}{dollar} and yield coefficient, Y were determined for 27 compounds which degraded under experimental conditions. The effect of different factors; temperature, compound concentration, biomass concentration and biomass source, on kinetic constant have been studied for benzene, toluene, ethyl benzene, phenol, 2,4-dimethyl phenol, resorcinol and dimethyl, diethyl, dibutyl and butyl benzyl phthalates. The results obtained will help in design of wastewater treatment plant and in determining the fate of these toxic compounds in natural and engineered environments. A method based on group contribution, to predict first-order biodegradation rate constant and Monod constants is developed and validated. More kinetic data is required to further extend this prediction method. |
