给水厂炭砂滤池设计参数探讨

Discussion on Design Parameters of Carbon-Sand Filter in Waterworks

目前炭砂滤池在给水厂的应用还不是十分广泛,其设计往往是各设计院依据自身的经验来进行,在参考总结水专项成果及国内大型给水厂工程应用案例和设计经验的基础上,提出了炭砂滤池的设计参数和设计要点。炭砂滤池适用于占地受限或经费紧张同时原水受有机微污染的水厂改造或新建;其进水水质控制指标浑浊度宜小于1 NTU;用于改造工程时,可采用0.4~0.5 m的砂层厚度和0.8~1.0 m的炭层厚度,用于新建工程时,可采用0.6~0.7 m的砂层厚度和1.0~2.0 m的炭层厚度,石英砂宜选用d10=0.55 mm的细砂滤料,活性炭宜选用8×30目煤质破碎炭和1.5 mm煤质柱状炭;正常设计滤速宜为6~9 m/h、空床接触时间宜为6~20 min;冲洗方式应采用日常冲洗和定期冲洗的方式,建议日常冲洗周期控制在1 d,定期冲洗周期控制在3~5 d。此外,活性炭的失效更换标准应以去除污染物效果能否达到目标值为主要依据,不宜以活性炭碘吸附值、亚甲蓝吸附值作为判断活性炭失效的标准。

At present,the application of carbon-sand filter in waterworks is not widely used,and its design is often carried out by each design institute according to their own experience.On the basis of referring and summarizing the achievements of water special projects and the application cases and design experience of large-scale water supply plant in China,the design parameters and design points of carbonsand filter were put forward.The carbon-sand filter is suitable for the reconstruction or new construction of water plants with limited land occupation or limited funds and organic micro pollutants exist in the influent.Its inflow water quality control index turbidity should be less than 1 NTU.When it is used for reconstruction projects,the sand layer thickness of 0.4-0.5 m and the carbon layer thickness of 0.8-1.0 m can be used.When it is used for new construction projects,the sand layer thickness of 0.6-0.7 m and the carbon layer thickness of 1.0-2.0 m can be used,the fine sand filter material with d10=0.55 mm should be selected for quartz sand,8×30 mesh coal crushed carbon and1.5 mm coal columnar carbon should be selected for active carbon.The normal filtration rate and contact time of empty bed are respectively 6-9 m/h and 6-20 min.The daily washing and regular washing methods are recommended.Daily washing cycle control is within 1 d,regular washing cycle control is within 3-5 d.In addition,it is suggested that the evaluation index of activated carbon failure should be mainly based on whether the removal effect of pollutants could reach the target value,not on the iodine adsorption value and methylene blue adsorption value of activated carbon.