A treatment technology from Neptune Benson that combines a novel electrode with ultraviolet disinfection to provide a chemical free treatment step treatment has been shown to meet the advanced oxidation process requirements of California’s indirect potable water reuse regulations.

The State of California Division of Drinking Water’s potable water reuse regulations require that all indirect potable reuse plants injecting into a groundwater basin include a UV advanced oxidation process (AOP) in the treatment train. These typically require the use of hydrogen peroxide or sodium hypochlorite. The regulation requires that the AOP achieves a minimum of a 0.5-log reduction of 1,4-dioxane as a surrogate for trace pollutants.

Neptune Benson took part in the nine month VenturaWaterPure recycled water project in collaboration with Carollo Engineers. According to the company, the electrode technology exceeded expectations during demonstration testing and met the AOP requirements of the regulations.

The electrode has been designed to work in combination with the company’s ETS-UV system to provide UV-mediated AOP. The advanced electrode arrangement consists of an anode and a cathode sited upstream of the UV system. These produce trace amounts hydroxyl radicals and react with dissolved salts to produce varying ratios of hypochlorite and hypochlorous acid, depending on the pH of the water.

‘The electrode-based AOP system represents a sea of change in AOP technology,’ says Jon McClean, Chief Technical Officer of ETS-UV. Processes typically involve the cost and handling of chemicals, and quenching of unused chemical after the AOP process, according to the company. The new system allows in situ generation that allows chlorine and hydroxyl radical mediated AOP. ‘It is an elegant and exciting breakthrough,’ McClean adds.