ABSTRACT

The discharge of raw wastewater into the environment can be a contamination source of Giardia spp. cysts and Cryptosporidium spp. oocysts. The UASB (Upflow Anaerobic Sludge Blanket) reactor is the most popular technology applied for wastewater treatment in Brazil, nevertheless there is little information concerning its capacity for (oo)cyst removal. In this context, this study investigated the occurrence and removal of Giardia spp. cysts and Cryptosporidium spp. oocysts by three different UASB reactors (i.e. Reactor A, B, and C) treating different wastewater types. In the wastewater influent, the concentration varied from 493.3 to 14,000 cysts·L^-1 for Giardia spp. and from ‘not detected’ to 53.3 oocysts·L^-1 for Cryptosporidium spp.. The (oo)cyst concentration increased after the anaerobic treatment in Reactors A and B, while Giardia spp. log-removal of 0.5 ± 0.2 was found in Reactor C. The increment in (oo)cyst concentration may happened due to the inefficacy for (oo)cyst removal by the specific UASB reactor and/or due to the reduction of matrix interference for reactor effluent samples in the detection method. The results suggest that hydraulic retention time (HRT) may be the key parameter for Giardia spp. removal by the UASB reactor. Furthermore, no parameter analysed (physical-chemical and indicator microorganisms) showed a common correlation with the (oo)cyst concentration in the three UASB reactors. Considering that official data of cryptosporidiosis and giardiasis cases are rarely reported in Brazil, monitoring Giardia spp. cysts and Cryptosporidium spp. oocysts in wastewater could be an alternative to estimate the occurrence of diseases in the served population.

摘要

未经处理的废水排放到环境中可能是贾第鞭毛虫的污染源。囊肿和隐孢子虫属。卵囊。UASB（上流式厌氧污泥毯）反应器是巴西最流行的废水处理技术，但关于其去除（oo）囊肿的能力的信息很少。在这种情况下，本研究调查了贾第鞭毛虫属的发生和去除。囊肿和隐孢子虫属。三个不同的 UASB 反应器（即反应器 A、B 和 C）处理不同类型的废水。在进水废水中，贾第虫的浓度从 493.3 到 14,000 个囊肿·L ^-1spp. 对于隐孢子虫属，从“未检测到”到 53.3 个卵囊·L ^-1 。. 在反应器 A 和 B 中厌氧处理后 (oo) 包囊浓度增加，而贾第鞭毛虫属。在反应器 C 中发现 0.5 ± 0.2 的对数去除。(oo) 包囊浓度的增加可能是由于特定 UASB 反应器对 (oo) 包囊去除的无效和/或由于反应器的基质干扰减少检测方法中的流出物样品。结果表明，水力停留时间（HRT）可能是贾第鞭毛虫的关键参数spp. 由 UASB 反应堆移除。此外，没有分析的参数（物理化学和指示微生物）显示与三个 UASB 反应器中的（卵）囊浓度有共同的相关性。考虑到巴西很少报告隐孢子虫病和贾第虫病病例的官方数据，因此监测贾第虫属。囊肿和隐孢子虫属。废水中的卵囊可以作为估计服务人群中疾病发生率的替代方法。