AWWA JAW53267

Biofiltration can be an effective drinking water treatment process when ozonation is practiced beforehand. The objectives and therefore the designs of these two processes are usually not related to biological treatment goals, and no effort has been made to determine the compatibility of the goals of these integrated treatment processes. The optimal application of ozone (O3) for disinfection is the minimum dose that provides a target level of microorganism inactivation. This dose was equivalent to the optimal O3 dose for biological treatment, defined as the minimum dose that would achieve the maximum relative BDOCrapid removal. Additionally, the O3 process is limited with respect to controlling the formation of BDCOrapid. Increasing the O3 dose beyond the optimal dose will result in little additional BDOCrapid formation, little additional release of biodegradable dissolved organic carbon to the distribution system, and an increase in the cost of operation. A conceptual approach for optimizing the O3 and biofiltration processes for biological treatment objectives is described for three case studies. The results indicate that biological treatment goals can be satisfied to a large degree while simultaneously meeting other drinking water treatment objectives such as disinfection and particle removal. Includes 21 references, tables, figures.