Modeling biodegradation of halogenated acetic acids in drinking water treatment

Halogenated acetic acids formed during the disinfection of drinking water have been found to be degradable during biological filtration and in distribution systems. Previous studies have shown varying results concerning the ability of microorganisms to degrade individual disinfection by-products (DBPs). Knowledge of the biological removal of these compounds is necessary to ensure the accuracy of empirical models in predicting concentrations of biodegradable disinfection by-products, such as haloacetic acids.; This study examined the ability of a microbial innoculum collected from a water treatment plant to degrade six haloacetic acids. All but trichloroacetic acid could be degraded when exposed to a biofilm. The order of degradability under this study was found to be monobromo- > monochloro- > bromochloro- > dichloro- > dibromo- > trichloro-acetic acid. Simple one-dimensional mathematical biofilm models were applied to experimental data in order to estimate Monod kinetic constants for the biological degradation of haloacetic acids.