Intrinsic Biodegradation Kinetics Of Chemicals
An understanding of the rate of biodegradation kinetics for specific industrial chemicals is useful when evaluating their treatability or their impact on treatment processes. The objective of kinetic assessments usually is to model the biodegradation reactions for specific chemicals using either pure cultures or defined mixed cultures, or natural mixed culture systems such as those that occur in treatment processes. Measurement of the biodegradation kinetics of organic chemicals usually is accomplished by dosing a microbial culture with a defined amount of organic chemical or wastewater followed by monitoring the reactions through measurement of oxygen uptake in aerobic tests or gas production in anoxic and methanogenic tests. Kinetic models are then fit to the oxygen uptake data using non-linear curve-fitting techniques to produce estimates of the kinetic parameters. Examples of intrinsic kinetic tests are shown in Figures A and B. Figure A show data for aniline biodegradation. In this case, sufficient information was available to model the residual soluble COD and the biomass concentrations. Figure B shows data for phenol. In this case, phenol was inhibitory to its own biodegradation until the concentration was reduced to below toxic levels.