三种深度处理工艺出水的微生物安全性比较

Comparison of Microbial Safety in Effluent of Three Advanced Drinking Water Treatment Processes

分别从浊度、颗粒数、细菌总数、HPC和浮游动物等方面进行研究,探讨了炭砂倒置工艺、炭砂滤池以及炭砂滤池/超滤复合工艺等三种给水深度处理技术对微生物安全性的保障作用。结果表明,炭砂滤池/超滤复合工艺对微生物的安全保障能力大大高于其他两种工艺。炭砂滤池/超滤复合工艺的出水水质非常稳定,浊度一般为0.01～0.03 NTU左右,平均为0.022 NTU,粒径>2μm的颗粒数<10个/mL;而其他两种工艺的出水浊度一般在0.1 NTU左右,颗粒数一般为几十至几百个/mL,且水质波动较大。炭砂过滤和炭砂倒置等两工艺出水的细菌总数和HPC均较高,存在一定的微生物风险;炭砂倒置工艺中的砂滤对降低微生物数量起到重要作用;复合工艺出水的细菌总数和HPC均很低。浮游动物能穿透炭砂滤层而出现在出水中;炭砂倒置工艺出水中的浮游动物数量有较大下降;复合工艺对浮游动物的截留效果非常好,出水中几乎不含浮游动物,只是偶尔检出数个轮虫。

Microbial safety in three drinking water advanced treatment processes including granular activated carbon filtration and sand filtration （ GACF - SF）, granular activated carbon and sand dual media filtration （GACSF）, and GACSF and ultrafihration （GACSF- UF） was investigated from aspects of turbidity, particle number, total bacteria number, HPC and zooplankton. The results show that GACSF- UF can ensure the microbial safety much more than other two processes. The water quality in the GACSF - UF is very stable. The turbidity is about 0.01 to 0.03 NTU, with the average of 0. 022 NTU. The particle number （ 〉 2 mm） is less than 10 CNT/mL. But the water quality in other two processes is fluctuant, with turbidity of about 0.1 NTU and particle number of tens to hundreds CNT/ mL. The total bacteria number and HPC are very high in the effluent of GACSF and GACF - SF, which has some risk to microbial safety. The sand filtration in GACF -SF plays an important role in reducing microbial organisms. The total bacteria number and HPC in the effluent of GACSF - UF are very low. Zooplankton exists in the effluent of GACSF after penetrating the granular activated carbon and sand dual media. The amount of zooplankton decreases greatly in the effluent of GACF - SF. GACSF - UF can remove zooplankton very well, with none or several rotifers detected.