A pilot-scale investigation of ozonation and advanced oxidation processes at Choa Chu Kang Waterworks

A two-year comprehensive advanced oxidation processes (AOPs) pilot test was completed for a Singapore waterworks in 2011–2013. This study focused on oxidative removal of spiked organic contaminants with ozone and ozone-based AOPs (ozone application together with hydrogen peroxide, which is necessary for AOPs). The ‘optimized H2O2 dosage’ test philosophy was verified during the test period – keeping the residual ozone at 0.3 mg/L in the water for disinfection purpose by minimizing the H2O2 dosage. This study also monitored the bromate concentration in both ozone- and AOP-treated water, and all the samples reported below the laboratory detection limit (<5 µg/L), which is also lower than the WHO Guidelines for Drinking Water Quality (<10 µg/L). For comparison, a low pressure UV-based AOP test was conducted in the final stage of the study. The electrical energy per order (E_EO) value is compared with ozone- and UV-based AOPs as well. The results indicated that ozone-based AOP with an optimized hydrogen peroxide dosage could be the most energy efficient option for this specific water matrix in terms of most selected compounds.