The use of catalytic ozonation, membrane and biofiltration for the control of water quality

• Main Authors: Yen-Chi Lu, 呂彥錡
• Other Authors: Kuan-Chung Chen
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/65269483180359580130

碩士 === 國立屏東科技大學 === 環境工程與科學系所 === 97 === This research was divided into two main parts. The first part was to compare the effectiveness of two catalysts (ZnO/α-Al2O3、Fe2O3/α-Al2O3) in hydroxyl radicals (OH˙) production under various catalyst dosages (0.0、0.5、1.0、1.5、2.0 g/L) to degrade para-chlorobenzonic acid (pCBA) in a heterogeneous catalytic ozonation system.Experimental parameters included pCBA concentration (10 μM), ozone dose (1.25 mg/L),gas flow rate (50 SCCM), pH 8 and water temperature (20 ℃). The second part was to chose the catalyst which had better catalyzed ability in the part one study and was used in the continuous heterogeneous catalytic ozonation system for raw water treatment. The treated water from the system was treated by the following units, membrane filtration and biotreatment. Experiments were carried out on raw water samples taken from the intake of Wo-Luo River (WLR), Pingtung, Taiwan. Experimental parameters included ozone dose (1.25 mg/L), gas flow rate (50 SCCM), water flow rate (30 mL/min) and water temperature (20 ℃). The addition amount of catalyst was 2 g/L. Ceramic membrane with pore size 5KD, and a one-day biofiltration were used. The experimental results of the first part showd that pCBA concentrations were almost completely degraded at 45, 40, 35, 35 min and 55, 50, 45, 40 min as the catalyst dosages ZnO/α-Al2O3 and Fe2O3/α-Al2O3 were 0.0, 0.5, 1.0, 1.5 and 2.0 g/L, respectively. This implies that ZnO/α-Al2O3 can produce more OH˙ than Fe2O3/α-Al2O3 and degrade pCBA faster. In addition, as the catalyst dosage increased, the pCBA concentration was completely degraded more quickly. The experimental results of the second part showed that using catalytic ozonation followed by biofiltration to treat WRL water resulted in the best removal efficiency on DOC, UV254, NH3-N and DBPs. It decreased the concentration of DOC, UV254, NH3-N, SDS-THMs and SDS-HAA9 by 69.4%、64.3%、97.4%、68.1% and 48.1%, respectively. After the treatment of catalytic ozonation and biofiltration, both NH3-N and trihalomethane levels were effective reduced and their concentrations in treated water met the Drinking Water Quality Standards (DWQS). The concentration of bromide was 15.6 μg/L in the WLR raw water, which resulted in very low bromate concentration production after the treatment of catalytic ozonation. The bromate level in treated water also met the DWQS. The subsequent ultrafiltration and biofiltration of catalytic ozonation were not able to remove the bromide and bromate from treated water.