ABSTRACT

Municipal wastewater is a source of pathogenic protozoan (oo)cysts and may play a significant role in spreading waterborne diseases. This scenario becomes more critical as treated sewage from municipal wastewater treatment plants (WWTP) is discharged into springs, which are often used for water supply, irrigation, recreation and, further downstream, indirect potable reuse, quite common in Brazil. This study aimed to elucidate, regarding microbiological quality, the performance of a full-scale WWTP, consisting of preliminary treatment, upflow anaerobic sludge blanket (UASB) reactor, activated sludge system and ultraviolet (UV) radiation disinfection. Pathogenic protozoa (Giardia spp. cysts and Cryptosporidium spp. oocysts), as well as microbiological indicators (Escherichia coli and Clostridium perfringens), were evaluated in terms of their removal. In addition, (oo)cyst viability and fluorescence reduction were assessed. By using the data obtained from this research, the prevalence of infection estimated for the population served by the WWTP was between 7.4% and 14.8% for giardiasis, and between 0.055% and 0.11% for cryptosporidiosis.

摘要

城市废水是致病性原生动物 (oo) 包囊的来源，可能在传播水传播疾病方面发挥重要作用。随着市政污水处理厂 (WWTP) 处理后的污水排放到泉水中，这种情况变得更加严重，这些泉水通常用于供水、灌溉、娱乐，以及下游的间接饮用水再利用，这在巴西很常见。本研究旨在从微生物质量方面阐明全面污水处理厂的性能，包括预处理、上流式厌氧污泥床 (UASB) 反应器、活性污泥系统和紫外线 (UV) 辐射消毒。致病性原生动物（贾第虫属囊肿和隐孢子虫属卵囊），以及微生物指标（对大肠杆菌和产气荚膜梭菌）的去除情况进行了评估。此外，评估了（oo）囊肿活力和荧光减少。通过使用从这项研究中获得的数据，估计污水处理厂服务人群的贾第虫病感染率在 7.4% 和 14.8% 之间，隐孢子虫病在 0.055% 和 0.11% 之间。