Romanazzi Valeria, Bonetta Silvia, Fornasero Stefania, De Ceglia Margherita, Gilli Giorgio, Traversi Deborah
Department of Public Health and Pediatrics, University of Torino, Piazza Polonia 94, 10126 Torino, Italy.
SMAT - Depuratore di Castiglione Torinese, Società Metropolitana Acque Torino S.p.A., Corso XI Febbraio 14, 10152 Torino, Italy.
J Environ Manage. 2016 Dec 15;184(Pt 2):170-177. doi: 10.1016/j.jenvman.2016.09.081. Epub 2016 Sep 30.
Wastewater treatment plants (WWTP) are an important source of surface water contamination by enteric pathogens, affecting the role of environmental water as a microbial reservoir. We describe the release to the environment of certain anaerobes of human and environmental concern. The work was focused on emerging microbial targets. They are tracing, by RT-qPCR, on WWTP effluents, both liquid and solid, when an anaerobic digestion step is included. The focus is placed on Clostridium spp. with the specific quantification of Clostridium perfringens, as typical bioindicator, and Clostridium difficile, as emerging pathogen not only confined into nosocomial infection. Moreover methanogens were quantified for their involvement in the anaerobic digestion, and in particular on Methanobrevibacter smithii as major methanogenic component of the human gut microbiome and as not conventional faecal indicator. In the water samples, a reduction, statistically significant, in all microbial targets was observed (p < 0.01), 2 log for the total bacteria, 1.4 log for the Clostridium spp. and M. smithii, 1 log for total methanogens, C. perfringens and C. difficile. The AD process contribute to a significant change in microbial levels into the sludge for total bacteria and total methanogens (p < 0.01), both when the input sludge are primary and secondary, while for the presence of Clostridium spp. and C. difficile there was not a significant change. The produced data are innovative showing which is the diffusion of such anaerobic microorganisms throughout the WWTP and opening a discussion on the implementation of possible techniques for a more efficient microbial removal from effluents, particularly bio-solids, to reduce the potential release of pathogens into the environment.
污水处理厂（WWTP）是肠道病原体污染地表水的重要来源，影响了环境水作为微生物储存库的作用。我们描述了某些受人类和环境关注的厌氧菌向环境中的释放情况。这项工作聚焦于新兴的微生物指标。通过逆转录定量聚合酶链反应（RT-qPCR）追踪包含厌氧消化步骤时污水处理厂液体和固体排放物中的这些指标。重点关注梭菌属，具体定量产气荚膜梭菌作为典型生物指示剂，以及艰难梭菌作为不仅局限于医院感染的新兴病原体。此外，对参与厌氧消化的产甲烷菌进行了定量，特别是对史密斯甲烷短杆菌进行了定量，它是人类肠道微生物群的主要产甲烷成分，也是非传统的粪便指示剂。在水样中，观察到所有微生物指标均有统计学显著下降（p < 0.01），总细菌下降2个对数，梭菌属和史密斯甲烷短杆菌下降1.4个对数，总产甲烷菌、产气荚膜梭菌和艰难梭菌下降1个对数。厌氧消化过程导致污泥中总细菌和总产甲烷菌的微生物水平发生显著变化（p < 0.01），无论输入的污泥是初级污泥还是二级污泥，而梭菌属和艰难梭菌的存在没有显著变化。所产生的数据具有创新性，显示了此类厌氧微生物在整个污水处理厂中的扩散情况，并开启了关于实施可能技术以更有效地从排放物特别是生物固体中去除微生物以减少病原体向环境中潜在释放的讨论。
