臭氧生物活性炭工艺运行中产生溴酸盐的可能性分析

为合理评估应用臭氧生物活性炭工艺中溴酸盐的生成情况,提出既能保证出水水质又能降低溴酸盐超标风险的方案.进行了小试与中试试验,系统地从原水水质和工艺参数两个方面入手,研究水质因素、初始溴离子浓度和臭氧氧化条件等对溴酸盐生成的影响,同时分析生物活性炭对溴酸盐的去除能力.结果表明:高初始溴离子浓度水平和臭氧接触程度(Ct值)促使更多BrOx-生成.在相同Ct值条件下,升高臭氧投加浓度可使溴酸盐生成量增高200%左右.以长江南京段江心洲夹江下游原水进行臭氧生物活性炭深度处理不会产生溴酸盐超标风险.生物活性炭(BAC)对于溴酸盐去除效果并不明显.运用臭氧生物活性炭工艺进行深度处理时,工艺中应着重注意控制溴酸盐在臭氧化过程中的生成而非依靠后续生物活性炭将其去除.

Possibility analysis for bromate generation during running ozone-biological activated carbon process

Laboratory and pilot scale experiments were carried on to assess the formation of bromate during ozone- biological activated carbon (O3-BAC), and further to provide practical parameters for drinking water treatment with low risk of excessive bromate. The effects of initial bromide concentration and oxidation condition on bromate formation were studied, and bromate removal capability of the O3-BAC was also evaluated. Results showed that the concentration of bromide ion and ozone exposure level (Ct value) could impose a positive impact on bromate formation. Under the same value of Ct, an increasing ozone concentration would enhance the formation of bromate at about 200%. Raw water from Nanjing reach of the Yangtze River was treated by O3-BAC process, and the results showed that bromate was not detected in the effluent. Moreover, bromate removal was rarely observed in the BAC process, therefore bromate control measures should be mainly took in the ozone phase rather than in the subsequent BAC process.