Jebri Sihem, Yahya Mariem, Rahmani Faten, Amri Islem, Hamdi Moktar, Hmaied Fatma
Laboratoire de Biotechnologies Et Techniques Nucléaires, CNSTN, Technopôle de Sidi Thabet, 2020, Sidi Thabet, Tunisia.
Laboratoire Ecologie Et Technologie Microbienne, Institut National Des Sciences Appliquées de Tunis, Tunis Carthage University, BP 676, 1080, Tunis, Tunisia.
Environ Sci Pollut Res Int. 2022 Oct;29(50):75575-75586. doi: 10.1007/s11356-022-21159-0. Epub 2022 Jun 3.
The main objective of this study is to evaluate the effect of irradiation by Gamma rays and Electron Beam (E-Beam) on naturally occurring microorganisms shed in healthcare wastewater issued from multi-specialties hospital. We examined the susceptibility of naturally occurring total indicator bacteriophages towards Gamma rays and E-Beam irradiation to evaluate their appropriateness as viral indicators for healthcare wastewater quality control. Results showed that healthcare wastewater is a rich matrix containing bacteriophages surrogates of pathogenic waterborne viruses (4.5 Log PFU/100 mL for SOMCPH and 2.3 Log PFU/100 mL for FRNAPH), antibiotic resistant bacteria (Mean concentrations from 2.3 to 5.5 Log CFU/100 mL), molds and yeasts (2.7 Log CFU/100 mL), and spores of Clostridium perfringens (Mean concentration of 3.3 Log CFU/100 mL). After E-Beam irradiation, naturally occurring bacteria in healthcare wastewater showed lower resistance patterns (D values ranging between 0.21 ± 0.005 and 0.59 ± 0.005) compared to those obtained after Gamma irradiation (D values ranging between 0.25 ± 0.015 and 0.70 ± 0.0001). Spores of Clostridium perfringens were the most resistant assayed microbes either after E-Beam (D values of 3.74 ± 0.005) or Gamma irradiation (D values of 4.77 ± 0.025) of collected samples. According to inactivation patterns, a dose of 10 kGy was sufficient for a complete inactivation of spores. Bacteriophages isolated from healthcare wastewater showed the same resistance patterns as those previously obtained in urban treated sewage and were inactivated using higher doses than waterborne bacteria (D values of SOMCPH 1.46 ± 0.057; D values of FRNAPH 1.03 ± 0.057). Their resistance to irradiation treatment in such complex matrix corroborates their use to survey the viral quality of healthcare wastewater before their discharge in the urban sanitation network. D value analysis showed that bacteria and bacteriophages inactivation by E-Beam irradiation required lower doses than those required for their inactivation using Gamma rays. According to inactivation patterns, a dose of 7 kGy was sufficient for total inactivation of both pathogenic bacteria and viruses. Thus, E-Beam irradiation seems to be an efficient physical pre-treatment process for healthcare wastewater treatment prior to its discharge in urban sanitation system to ensure compliance with environmental standards and protect public health.
本研究的主要目的是评估伽马射线和电子束（E 束）辐照对多专科医院产生的医疗保健废水中天然存在的微生物的影响。我们检测了天然存在的总指示性噬菌体对伽马射线和 E 束辐照的敏感性，以评估它们作为医疗保健废水质量控制的病毒指标的适用性。结果表明，医疗保健废水是一个丰富的基质，含有致病性水传播病毒的噬菌体替代物（SOMCPH 为 4.5 Log PFU/100 mL，FRNAPH 为 2.3 Log PFU/100 mL）、抗生素抗性细菌（平均浓度为 2.3 至 5.5 Log CFU/100 mL）、霉菌和酵母菌（2.7 Log CFU/100 mL）以及产气荚膜梭菌的孢子（平均浓度为 3.3 Log CFU/100 mL）。E 束辐照后，医疗保健废水中天然存在的细菌显示出比伽马辐照后更低的抗性模式（D 值在 0.21±0.005 和 0.59±0.005 之间）（伽马辐照后的 D 值在 0.25±0.015 和 0.70±0.0001 之间）。产气荚膜梭菌的孢子是采集样品经 E 束（D 值为 3.74±0.005）或伽马辐照（D 值为 4.77±0.025）后检测到的最具抗性的微生物。根据失活模式，10 kGy 的剂量足以使孢子完全失活。从医疗保健废水中分离出的噬菌体显示出与先前在城市处理污水中获得的相同抗性模式，并且使用比水传播细菌更高的剂量使其失活（SOMCPH 的 D 值为 1.46±0.057；FRNAPH 的 D 值为 1.03±0.057）。它们在这种复杂基质中对辐照处理的抗性证实了它们在医疗保健废水排放到城市卫生网络之前用于检测其病毒质量的用途。D 值分析表明，E 束辐照使细菌和噬菌体失活所需的剂量低于伽马射线使其失活所需的剂量。根据失活模式，7 kGy 的剂量足以使致病细菌和病毒完全失活。因此，E 束辐照似乎是医疗保健废水在排放到城市卫生系统之前进行有效物理预处理的过程，以确保符合环境标准并保护公众健康。
