Behaviour of ozonation by-products during advanced drinking water treatment with pearl river water
1 College of Environmental Science and Engineering, South China University of Technology, Guangzhou 510006, China
2 The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters of Ministry of Education, Guangzhou 510006, China
3 Shantou Polytechnic, Shantou 515041, China
2 The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters of Ministry of Education, Guangzhou 510006, China
3 Shantou Polytechnic, Shantou 515041, China
Abstract
Simulation experiments were conducted to investigate the behaviour of ozonation by-products and the removal of organic matter in the treatment of the Pearl River raw water. The treatment processes include pre-ozonation, conventional treatment processes (coagulation/sedimentation and sand filtration), post-ozonation and granular activated carbon (GAC) filtration. Treatment efficiency of each unit process was evaluated by using several parameters such as permanganate index (CODMn), ultraviolet absorbance at 254 nm (UV254), bromate (BrO3-) and formaldehyde. The overall conversion rates of BrO3-in the six water samples were 0.43~5.54 %. Treated water flowed through the pre-ozonation unit process in which CODMn and UV254 were greatly removed. The conventional treatment processes had poor ability to remove BrO3-, but were effective in the removal of formaldehyde. In the post-ozonation unit process, the concentrations of BrO3-and formaldehyde reached the highest value. GAC filtration enhanced the removal efficiency of BrO3-compared with the conventional treatment processes. Water samples from the Xijiang and Beijiang River of the Pearl River basin contained higher concentrations of BrO3-and lower values of CODMn, UV254 and formaldehyde in the final effluents than those from the Dongjiang River.
Keywords
bromate; formaldehyde; granular activated carbon; ozone; Pearl River raw water