南水北调汉江水质变化后某水厂臭氧-活性炭深度处理工艺优化研究

Operation effect of O_(3)-BAC advanced treatment process in a water plant after water quality change of Hanjiang River due to the South-to-North Water Diversion Project

为研究南水北调中线工程通水后汉江水质的变化及评价沿线某水厂臭氧-活性炭深度处理工艺运行效果,研究分析了2013至2021年汉江水质变化趋势,检测水厂各工艺段出水常规水质指标,并考察了2022年1至4月间调控PAC、NaClO和预、主臭氧投加量对出水水质的影响。结果表明,南水北调通水后一个月,汉江水pH、色度、COD_(Mn)、菌落总数较通水前的同期分别升高了5.6%、57.1%、38.4%、162.1%,此后这些指标与通水前基本无显著性差异,但2019至2021年CODMn和菌落总数指标有升高的趋势。增设主臭氧-活性炭工艺运行4年后对COD_(Mn)、UV_(254)、NH_(3)-N的去除率比常规处理提高了12.2%、18.5%、8.3%,对浑浊度、TOC去除效果提高不明显。活性炭运行4年后,碘吸附值及亚甲蓝吸附值分别下降了82.0%及82.2%,达到生物活性炭的成熟阶段。日常运行可采用炭滤池出水0.30NTU所对应的二级预警作为限值控制,保障出水浑浊度的稳定。调控预、主臭氧投加量及比例,可使出厂水的COD_(Mn)小于2.0mg/L。

In order to study the changes in water quality in the Hanjiang River after the middle route of the South-to-North Water Diversion Project and evaluate the operation effect of ozone-activated carbon advanced treatment process in a water plant along the route,this study analyzed the changing trend of water quality in the Hanjiang River from 2013 to 2021 and tested the conventional water quality indexes of each process section of the water plant.The influence of regulating PAC,NaClO,pre-ozonation,and main ozonation dosage on effluent quality from January to April 2022 was investigated.The results showed that pH,chroma,COD_(Mn),and the total number of colonies in Hanjiang River in the month after the project increased by 5.6%,57.1%,38.4%,and 162.1%,respectively,compared with the same period in 2014.These indicators were basically no significant difference compared with those before the project,but COD_(Mn)and the total number of colonies showed an increasing trend from 2019 to 2021.After adding the main ozone-activated carbon process,the removal rates of COD_(Mn),UV_(254),and NH_(3)-N were increased by 12.2%,18.5%,and 8.3%compared with the conventional treatment,and the removal effects of turbidity and TOC were not significantly improved.After the operation of activated carbon for four years,the iodine number and methylene blue adsorption decreased by 82.0%and 82.2%,respectively,and biological activated carbon reached the mature stage.The second-level early warning corresponding to O.30 NTU of effluent from the carbon filter can be used as the limit control in daily operation to ensure the stability of effluent turbidity.The CODmn of treated water can be less than 2.O mg/L by adjusting the dosage and proportion of pre-ozonation and main ozonation.