Results from UFC tests will enable direct comparison of DBP formation in different water sources. A new chlorination approach has been developed for assessing disinfection by‐product (DBP) formation under constant, yet representative conditions. The rationale used in the development of the uniform formation conditions (UFC) test and the results of a parametric sensitivity analysis are presented. Within the acceptable range of conditions, the DBP formation varied by less than 4 percent for the three waters examined. UFC test results will allow a direct comparison of DBP formation among different waters and allow the evaluation of how treatment changes affect DBP formation in a specific water.

Separation treatment processes are being investigated as a way to control the formation of disinfection by‐products (DBPs) in finished waters. These processes remove natural organic matter before a disinfectant is applied, thus limiting the amount of material available to form DBPs. Four separation processes were examined in this study—granular activated carbon adsorption, powdered activated carbon adsorption, anion exchange, and membrane filtration—using two waters. Results showed that (1) as the dissolved organic carbon (DOC) decreased, the chlorination of diluted organic matter solutions held at constant bromide concentrations yielded a shift to brominated trihalomethanes (THMs); (2) at low DOC concentrations, the percentage of formed brominated trihalomethanes was higher in treated effluent than in influent water; and (3) the processes were most effective for controlling the formation of chloroform and least effective for controlling the formation of bromoform. Based on these results, it can be concluded that effective control of brominated THMs by these separation processes may be difficult for waters containing significant concentrations of bromide.

The inactivation of Cryptosporidium parvum oocysts and the formation of bromate were assessed simultaneously by performing experiments with a full-scale ozone bubble-diffuser contactor used for drinking water disinfection. Fluorescence-dyed polystyrene microspheres were used as surrogates for C. parvum oocysts. Semi-batch ozonation experiments were performed to determine the fluorescence-intensity decay of individual microspheres, which was measured by flow cytometry. The results obtained with the microspheres were correlated to the inactivation kinetics of C. parvum oocysts by choosing an appropriate threshold fluorescence intensity below which microspheres were considered to be equivalent to nonviable oocysts. A mathematical model was then used to predict the inactivation efficiency and bromate formation. The contactor hydrodynamics were characterized by running tracer tests, and the kinetic parameters for ozone decomposition and bromate formation were obtained by performing batch experiments. Model predictions were in good agreement with full-scale experimental results. Additional model simulations revealed that ozone contactors should be designed with the lowest possible backmixing so that the target inactivation efficiency can be achieved with the lowest possible formation of bromate.