饮用水臭氧生物活性炭净化效果与传统工艺比较

Comparison of O3-BAC Combination and Conventional Processes on Removal of Pollutants for Treating Drinking Water

高浓度有机物,高NH4+-N的黄浦江原水经预臭氧→高密度澄清池→砂滤→后臭氧→生物活性炭组合处理工艺后,水质明显优于传统处理工艺.其中臭氧生物活性炭部分对CODMn(高锰酸盐指数)和NH4+-N的去除率分别达到30.4%和18.9%.由于预臭氧相对预氯化能更好地发挥其氧化助凝作用,组合工艺中常规工艺部分对CODMn和NH4+-N的去除率分别达29.6%和81.0%,而传统工艺对CODMn和NH4+-N的去除率仅分别为22.3%和61.5%.考察了2种工艺出水藻毒素,溴酸盐浓度、三卤甲烷生成潜能以及相对分子质量分布等指标,表明组合处理工艺更容易去除小分子有机物(臭氧生物活性炭部分对小于<1kD的有机物去除率大于70%),三卤甲烷生成潜能比传统工艺降低41%,且藻毒素和溴酸盐指标均低于我国饮用水标准.由于组合处理工艺能基本去除NH4+-N,可以采用自由氯消毒用以解决传统氯胺消毒带来的亚硝胺等消毒副产物风险和氯胺的气味问题.在高温季节组合工艺澄清池中出现藻类大量生长的现象,可能与臭氧持续消毒时间较短有关,可通过联合预臭氧和预氯化工艺对组合处理工艺中预处理方式进行改造.

The treatment effect of the combination process（pre-ozonation→high-density clarifier→sand filter→post ozonation→biological activated carbon（BAC） filter） was much better than that of the conventional process in treating the Huangpu River water,which is especially suit to high organic material and NH＋4-N in water.The removal efficiencies of CODMn and NH＋4-N by the post ozonation-BAC process were up to 30.4% and 18.9% respectively.And as the pre-ozonation process played a better role than pre-chlorination process in aid-coagulation,the removal efficiencies of CODMn and NH＋4-N were up to 29.6% and 81% respectively in traditional part of combination process.However,the removal efficiencies of CODMn and NH＋4-N were only 22.3% and 61.5% in the conventional process.In addition,the concentrations of algae toxins,trihalomethanes,bromate,molecular weight distribution and the related parameters of the BAC effluent were also investigated.The results show that the organic material with low molecular weight can be more easily removed by the post ozonation-BAC processes（removal efficiency of organic material with molecular weight less than 1 kD is more than 70%）.Tihalomethanes formation potential is 41% less than that of the conventional process.Besides,the microcystin and bromate concentrations are lower than drinking water standards in China.Moreover,the free chlorine disinfection can be used because the NH＋4-N can be mostly removed by the combination process,which can avoid the generation of nitrosamine as well as the odor and test problem by chloramine disinfection.However,the combination process also has some disadvantages such as the growth of algae on the purification structures during high-temperature season as the reaction time of ozone is relatively short.This problem may be solved by the combinated pre-ozonation and pre-chlorination process.