Assessing the biodegradability of trace organic contaminants during wastewater treatment

This work was performed to better understand the factors that impact trace organic compound (TOrC) biodegradation kinetics in mixed microbial cultures. To accomplish this goal, optimized short-term batch tests using TOrC and identified TOrC surrogates were conducted using lab-scale activated sludge cultures. In these optimization experiments, the initial TOrC/surrogate concentration, readily biodegradable carbon concentration (rbCOD) and dissolved oxygen (DO) concentrations were varied. This work confirms that TOrC biotransformation is best described using pseudo-first order kinetics. In contrast, results from surrogate experiments indicate that the current approach to aerobic respirometry is not sufficiently sensitive for resolving TOrC biotransformation versus endogenous respiration. Results from short-term batch test optimization also indicate that parameters estimated from depletion tests performed at artificially high TOrC concentrations are statistically similar to parameters estimated at low TOrC concentrations. This suggests that interrogation of the biomass can be performed at high TOrC concentrations, which would reduce the cost of sample processes associated with working at lower concentrations.