AWWA WQTC62485

Recent studies originating from this laboratory and the Newport News Water Works has confirmed the bacterial degradation of various disinfection byproducts (DBPs) in drinking water. This bacterial degradation appears to be common in areas of the distribution system that have low levels of residual chlorine and high heterotrophic bacterial levels. Two specific bacteria have been identified that are capable of degrading a variety of haloacetic acids (HAAs) and other DBPs using a specific halodehalogenase enzyme. These bacteria have been cultured in the laboratory and identified as a Burkholderia and Sphingomonas species. A rather effective and relatively simple colorimetric method has been developed which is able to detect the release of HCl or HBr from the HAAs during the enzymatic degradation. Using this colorimetric method the authors have been able to examine the speciation of the enzymatic degradation and selectivity of the two bacteria for various HAAs and haloacetonitriles (HANs). This colorimetric method could be very adaptable to future laboratory procedures involving the detection of bacterial species capable of HAA degradation in a particular distribution system. This method could be useful to those laboratories involved in the selection and monitoring for the future IDSE requirement for stage 2 of the disinfection byproduct rule. Includes 15 references, tables, figures.