Extended investigation to evaluate the reliability of Ozone-BAC treatment as a CEC removal barrier in potable reuse applications

Ozonation-Biological Activated Carbon (Ozone-BAC) process reliability in terms of contaminant removal over time is becoming increasingly important to the potable water industry. Field verification of ozone-BAC performance from startup to achieving steady state based on real-time tools is necessary for regulatory approval and develop operational protocols. Consequently, this study involved 19 months of continuous field-scale demonstration of two ozone-BAC systems with different Empty Bed Contact Times (EBCTs) with observations of removal of contaminants of emerging concern (CECs). Findings from this effort filled the gap in the literature regarding transition of granular activated carbon (GAC) to BAC in potable reuse applications. Lowering influent CEC concentrations to heavily loaded BAC resulted in significant desorption resulting in elevated levels of CECs in the BAC effluent which could be a serious concern if downstream polishing steps such as granular activated carbon (GAC) is not available.