Enhanced treatment technology for Yangtze River water in a water purification plant in Tianjin

Abstract

The main water source of a water purification plant in Tianjin is Yangtze River water from Mid-route of South-to-North Water Transfer Project. On the basis of conventional processes, the plant has added pre-ozone, post-ozone and activated carbon enhancement processes to improve the quality of effluent. In this study, a small-scale experimental device was set up to investigate the effect of each process in enhancing of the conventional processes for treating Yangtze River water. The results indicated that the optimal dosages of flocculants PAC and FeCl3 were both 17 mg/L. The addition of pre- or post-ozone process to the conventional process could effectively enhance the removal of organic matter. The addition of activated carbon process could enhance the removal of turbidity and organic matter at the same time. The addition of post-ozone and activated carbon process could significantly enhance the removal of turbidity and organic matter. The optimum dosage for both pre- and post-ozone both were 1.0 mg/L. When the concentration of bromine ion in the raw water was up to 150 μ/L, the dosage of ozone in the conventional-post-ozone process and pre-ozone-conventional-post ozone process should be adjusted to ≤0.5 mg/L.

Keywords

• pre-ozone
• ozone-activated carbon
• advanced treatment
• yangtze river water
• bromate salt