The Impact of Natural Variation of OH Radical Demand of Drinking Water Sources on the Optimum Operation of the UV/H2O2 Process.

Hydroxyl radical (•OH) water demand is a key parameter which impacts the design and operation of UV/H2O2 process in water remediation projects. Long-term monitoring of the •OH water demand in water sources used for drinking water production indicated significant seasonal variations of this parameter (1.59×10<sup>4 to 4.98×10<sup>4 s-1), which coincided with the occurrence of algal blooming events. Pilot-scale tests at a drinking water treatment plant confirmed that the UV/H2O2 process performance for contaminant removal is predictable when the •OH water demand is accurately determined through a validated experimental method. A predictive tool was developed to identify the optimum operating conditions of the UV system with the UV/H2O2 process and it was used to demonstrate the significant impact of seasonal variation of •OH water demand on the operating costs.