Study on full-scale H₂O₂/O₃–UBAC process for removing organic matters in drinking water treatment

Abstract

Ozone–biological activated carbon process (O₃–BAC) is an advanced drinking water treatment technology that has been widely used. The combined process of O₃/H₂O₂-upflow BAC filter (UBAC)—sand filter has been adopted by a drinking water treatment plant. The paper summarizes the effect of advanced oxidation process (O₃ and O₃/H₂O₂) on the overall combined process in two seasons. The influence of different O₃/H₂O₂dosages on the effluent water quality is investigated and the effectiveness of the combined process is analyzed. The results indicate that O₃ can effectively decompose organic matters in water and increase the biodegradability of dissolved organic carbon. The organic matters removal rate of combined process increases as ozone dosage increases. Biodegradable dissolved organic carbon (BDOC) after ozonation increases by 30, 93, and 101% with increasing ozone dosages from 1.0, 1.5 to 2.0 mg/L. The removal rates of BDOC by the combined process reached 39, 45, and 73%, respectively. H₂O₂/O₃ does not give better effect than O₃ alone. Turbidity removal rate by sand filtration remains stable, which is above 87%. Higher temperature is favorable to microbial degradation by UBAC and sand filter.

Keywords:

• Drinking water treatment
• Ozonation
• O₃/H₂O₂
• Advanced oxidation process
• Biological activated carbon

Acknowledgments

This work was supported by the National Natural Science Foundation of China (51278285), Shandong Provincial Natural Science Foundation, China (ZR2010EM019), and the National Science and Technology Major Project of China (2012ZX07404-003).