Mbonimpa E G, Blatchley E R, Applegate B, Harper W F
Department of Systems Engineering and Management, Air Force Institute of Technology, WPAFB, Ohio, USA E-mail:
School of Civil Engineering, Purdue University, West Lafayette, Indiana, USA.
J Water Health. 2018 Oct;16(5):796-806. doi: 10.2166/wh.2018.071.
UVA and UVB can be applied to solar disinfection of water. In this study, the inactivation and photoreactivation of viruses and bacteria in the UVA-B range were analyzed. MS2 and T4 bacteriophages, and Escherichia coli were used as surrogates to quantify dose-response behaviors. Inactivation in UVC was used to validate the methodology and to expand the inactivation action spectra. The results showed log-linear inactivation for MS2 and T4 in the 254-320 nm wavelength range. T4 inactivation was consistently faster than MS2 (except at 320 nm), and for both phages, inactivation decreased with increasing wavelength. The dose-response of bacteria exhibited a lag at low doses, possibly because the photons must strike a discrete number of critical targets before growth stops. A tail was present at high doses for some wavelengths, perhaps due to clumping or the presence of subgroups with higher resistance. The inactivation action spectra for bacteria exhibited a reduction in inactivation as wavelength increased. No bacterial inactivation was observed beyond 320 nm at doses applied. After inactivation at 297 nm (UVA), bacteria regained viability through photoreactivation, and repair increased with increase in photoreactivating light exposure time. This implies additional doses above inactivation thresholds are required to cause irreversible damage. These results are useful for designing solar disinfection systems.
紫外线A（UVA）和紫外线B（UVB）可用于水的太阳能消毒。在本研究中，分析了UVA - B范围内病毒和细菌的灭活及光复活情况。使用MS2和T4噬菌体以及大肠杆菌作为替代物来量化剂量反应行为。利用紫外线C（UVC）中的灭活来验证方法并扩展灭活作用光谱。结果表明，在254 - 320纳米波长范围内，MS2和T4呈对数线性灭活。T4的灭活始终比MS2快（320纳米处除外），并且对于两种噬菌体，灭活都随波长增加而降低。细菌的剂量反应在低剂量时表现出滞后，可能是因为光子必须击中一定数量的关键靶点才能使生长停止。在某些波长的高剂量下出现了拖尾现象，这可能是由于聚集或存在具有更高抗性的亚群。细菌的灭活作用光谱随波长增加而灭活减少。在所施加的剂量下，320纳米以上未观察到细菌灭活。在297纳米（UVA）灭活后，细菌通过光复活恢复活力，并且修复随着光复活光照时间的增加而增强。这意味着需要高于灭活阈值的额外剂量才能造成不可逆损伤。这些结果对于设计太阳能消毒系统很有用。
