Lee Shun-Hwa, Lee Chul-Hee, Kim Yun-Hee, Do Ju-Hee, Kim Seung-Hyun
Department of Environmental Engineering, Yeungnam University, Korea.
J Water Health. 2007 Mar;5(1):163-9. doi: 10.2166/wh.2006.051.
This study was conducted in preparation of a pending Cryptosporidium regulation in Korea. The study had two main objectives: 1) to examine the occurrence of Cryptosporidium oocysts in the Nakdong River; and 2) to evaluate their removal during water treatment. Occurrence of Giardia cysts was also examined. Average (arithmetic mean) numbers of Cryptosporidium oocysts and Giardia cysts at the treatment intake site were 2.61(-1) and 4.81(-1), respectively. Generally, the number of Giardia cysts was higher than that of Cryptosporidium oocysts at more sites, but the difference was minimal. Comparison of tributaries indicated that livestock wastes were more serious pollutants than sewage in terms of protozoa contamination. In general, fewer oocysts and cysts were detected during winter. No correlation was found for such water quality parameters as T-N, T-P, TOC, DO, pH and temperature with the numbers of oocysts and cysts except for suspended solids, which showed the highest correlation (R2 = 0.55). Removal of Cryptosporidium oocysts was evaluated using a Cryptosporidium tracer, which has similar characteristics to Cryptosporidium oocysts. The tracer removal depended on turbidity removal. Coagulation followed by sedimentation resulted in 1.2-1.5 log removal of the tracer under optimal conditions. Filtration resulted in 1.3-1.5 log removal of the tracer. These treatability experiments showed that traditional water treatment processes could achieve 2.5-3.0 log removal of the oocysts.
本研究是为韩国即将出台的隐孢子虫相关规定而开展的。该研究有两个主要目标：1）检测洛东江中隐孢子虫卵囊的存在情况；2）评估其在水处理过程中的去除情况。同时也检测了贾第虫包囊的存在情况。在处理进水口处，隐孢子虫卵囊和贾第虫包囊的平均（算术平均）数量分别为2.61（-1）和4.81（-1）。一般来说，在更多的地点，贾第虫包囊的数量高于隐孢子虫卵囊，但差异极小。支流比较表明，就原生动物污染而言，畜禽粪便比污水是更严重的污染物。总体而言，冬季检测到的卵囊和包囊较少。除悬浮固体外，总氮、总磷、总有机碳、溶解氧、pH值和温度等水质参数与卵囊和包囊数量之间未发现相关性，悬浮固体显示出最高的相关性（R2 = 0.55）。使用与隐孢子虫卵囊具有相似特性的隐孢子虫示踪剂评估隐孢子虫卵囊的去除情况。示踪剂的去除取决于浊度的去除。在最佳条件下，混凝后沉淀可使示踪剂去除1.2 - 1.5个对数级。过滤可使示踪剂去除1.3 - 1.5个对数级。这些可处理性实验表明，传统的水处理工艺可实现卵囊2.5 - 3.0个对数级的去除。
