预氯化/粉炭工艺对原水藻源风险的控制效能

Efficiency of Pre-chlorination/Powdered Carbon Process in Controlling Algal Risks in Raw Water

摘要:

选用了5种粉末活性炭，开展与预氯化联用的粉末活性炭种类优选和与氯的交互影响研究。结果表明，5种粉末活性炭均可有效吸附三氯甲烷，吸附速率变化均符合拟二级动力学规律，回归相关系数均大于0.99，木质活性炭（k=0.419 12）和椰壳活性炭Ⅰ（k=0.386 93）吸附效果最好。余氯的存在会降低粉末活性炭对三氯甲烷的吸附速率，但未改变各粉末活性炭吸附效果的优劣顺序。在原水背景下，椰壳活性炭Ⅰ和木质活性炭对2-甲基异莰醇（2-MIB）去除效率在60%以上，对土臭素（GSM）去除效率在90%以上，对三卤甲烷吸附效率最高（28%）。尽管加氯会减低活性炭的吸附效率，但是其不影响不同炭型吸附的优劣顺序，木质活性炭和椰壳活性炭Ⅰ的效果依然最佳，煤质活性炭表现较差。将粉末活性炭性质与三氯甲烷、嗅味物质的去除性能进行相关性分析发现，平均孔径、碘值、亚甲基蓝值和总孔容积的相关性较为显著，平均孔径的相关系数最高，在比选优质粉末活性炭时可以将平均孔径作为重要参考因素。

关键词:原水;预氯化;粉末活性炭;嗅味;消毒副产物

Abstract:

Five powdered activated carbons （PACs） were selected to carry out the study on the preference of powdered activated carbons for use in conjunction with pre-chlorination. The results show that all five powdered activated carbons can effectively adsorb trichloromethane， and the changes of adsorption rate are in accordance with the proposed second-order kinetic law， and the regression correlation coefficients are all greater than 0.99， with the best adsorption effect of wood activated carbon （k=0.419 12） and coconut shell activated carbon Ⅰ （k=0.386 93）. The presence of residual chlorine decreased the rate of adsorption of trichloromethane by powdered charcoal， but it did not change the order of superiority of the adsorption effect of each powdered activated carbon. In raw water background， coconut shell activated carbon I and wood activated carbon had more than 60% removal efficiency for 2-methylisopropanol（2-MIB）， more than 90% for Geosmin （GSM），and the highest adsorption efficiency for trihalomethanes （28±5%）. In the combined chlorine-powdered activated carbon process， the order of the advantages and disadvantages of the different activated carbon types did not change， with wood activated carbon and coconut shell activated carbon I remaining the most effective， and coal activated carbon performing poorly. Correlation analysis of powder carbon properties with the removal performance of trichloromethane and olfactory substances found that the correlation of average pore size， iodine value， methylene blue value and total pore volume was more significant， and the correlation coefficient of average pore size was the highest， and the average pore size can be taken as an important reference factor in the comparison of high-quality powdered activated carbon.

Key words:raw water;pre-chlorination;powered activated carbon;odorous substances;disinfection by-products