Environmental Research Institute, University of León, León, Spain.
Microb Ecol. 2011 Apr;61(3):684-92. doi: 10.1007/s00248-010-9791-6. Epub 2011 Jan 5.
A waste stabilisation pond (WSP) system formed by two anaerobic ponds, a facultative pond and a maturation pond was studied from December 2003 to September 2004 in north-western Spain in order to evaluate its efficiency in the removal of faecal indicator bacteria (total coliforms, Escherichia coli, faecal streptococci), coliphages, helminth eggs and protozoan (oo)cysts (Cryptosporidium and Giardia). Furthermore, sediment samples were collected from the bottom of the ponds to assess the settling rates and thus determine the main pathogen removal mechanisms in the WSPs system. The overall removal ranged from 1.4 log units for coliphages in the cold period to 5.0 log units for E. coli in the hot period. Cryptosporidium oocysts were reduced by an average of 96%, Giardia cysts by 98% and helminth eggs by 100%. The anaerobic ponds showed significantly higher surface removal rates (4.6, 5.2 and 3.7 log (oo)cysts/eggs removed m(-2) day(-1), respectively) than facultative and maturation ponds. Sunlight and water physicochemical conditions were the main factors influencing C. parvum oocysts removal both in the anaerobic and maturation ponds, whereas other factors like predation or natural mortality were more important in the facultative pond. Sedimentation, the most commonly proposed mechanism for cyst removal had, therefore, a negligible influence in the studied ponds.
一个由两个厌氧塘、一个兼性塘和一个熟化塘组成的废物稳定塘（WSP）系统，于 2003 年 12 月至 2004 年 9 月在西班牙西北部进行了研究，以评估其去除粪便指示菌（总大肠菌群、大肠杆菌、粪链球菌）、噬菌体、寄生虫卵和原生动物（oo）囊（隐孢子虫和贾第虫）的效率。此外，还从池塘底部采集了沉积物样本，以评估沉降率，从而确定 WSP 系统中主要的病原体去除机制。总体去除率范围从冷期噬菌体的 1.4 个对数单位到热期大肠杆菌的 5.0 个对数单位。隐孢子虫卵囊平均减少 96%，贾第虫包囊减少 98%，寄生虫卵减少 100%。厌氧塘的表面去除率明显高于兼性塘和熟化塘（分别为 4.6、5.2 和 3.7 log (oo)卵囊/卵去除 m(-2)天(-1)）。阳光和水的物理化学条件是影响厌氧塘和熟化塘中 C. parvum 卵囊去除的主要因素，而捕食或自然死亡等其他因素在兼性塘中更为重要。因此，沉淀作为囊去除的最常见机制，在研究中的池塘中影响甚微。
