Nasser Abidelfatah M, Benisti Neta-Lee, Ofer Naomi, Hovers Sivan, Nitzan Yeshayahu
a Water Quality Research Laboratory, Ministry of Health, Public Health Laboratories , Tel Aviv , Israel.
b Faculty of Life Sciences, Bar-Illan University , Ramat Gan , Israel.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2017 Jan 28;52(2):144-148. doi: 10.1080/10934529.2016.1237140. Epub 2016 Oct 21.
Advanced wastewater treatment processes are applied to prevent the environmental dissemination of pathogenic microorganisms. Giardia lamblia causes a severe disease called giardiasis, and is highly prevalent in untreated wastewater worldwide. Monitoring the microbial quality of wastewater effluents is usually based on testing for the levels of indicator microorganisms in the effluents. This study was conducted to compare the suitability of fecal coliforms, F+ coliphages and sulfide reducing clostridia (SRC) as indicators for the reduction of Giardia cysts in two full-scale wastewater treatment plants. The treatment process consists of activated sludge, coagulation, high rate filtration and either chlorine or UV disinfection. The results of the study demonstrated that Giardia cysts are highly prevalent in raw wastewater at an average concentration of 3600 cysts/L. Fecal coliforms, F+ coliphages and SRC were also detected at high concentrations in raw wastewater. Giardia cysts were efficiently removed (3.6 log) by the treatment train. The greatest reduction was observed for fecal coliforms (9.6 log) whereas the least reduction was observed for F+ coliphages (2.1 log) following chlorine disinfection. Similar reduction was observed for SRC by filtration and disinfection by either UV (3.6 log) or chlorine (3.3 log). Since F+ coliphage and SRC were found to be more resistant than fecal coliforms for the tertiary treatment processes, they may prove to be more suitable as indicators for Giardia. The results of this study demonstrated that advanced wastewater treatment may prove efficient for the removal of Giardia cysts and may prevent its transmission when treated effluents are applied for crop irrigation or streams restoration.
采用先进的废水处理工艺来防止病原微生物在环境中传播。蓝氏贾第鞭毛虫会引发一种名为贾第虫病的严重疾病，在全球未经处理的废水中普遍存在。监测废水排放的微生物质量通常基于检测排放物中指示微生物的水平。本研究旨在比较粪大肠菌群、F+ 噬菌体和硫化物还原梭菌（SRC）作为两个全规模废水处理厂中贾第虫囊肿减少指标的适用性。处理工艺包括活性污泥、混凝、高速过滤以及氯消毒或紫外线消毒。研究结果表明，贾第虫囊肿在原废水中普遍存在，平均浓度为3600个囊肿/升。原废水中还检测到高浓度的粪大肠菌群、F+ 噬菌体和SRC。处理流程有效地去除了贾第虫囊肿（3.6个对数级）。氯消毒后，粪大肠菌群减少最多（9.6个对数级），而F+ 噬菌体减少最少（2.1个对数级）。通过过滤以及紫外线（3.6个对数级）或氯（3.3个对数级）消毒，SRC的减少情况类似。由于发现F+ 噬菌体和SRC在三级处理工艺中比粪大肠菌群更具抗性，它们可能被证明更适合作为贾第虫的指标。本研究结果表明，先进的废水处理对于去除贾第虫囊肿可能是有效的，并且当处理后的废水用于作物灌溉或溪流修复时，可以防止其传播。
