Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Computational and Systems Biology, University of Pittsburgh Medical School, Pittsburgh, PA 15261, USA.
Water Res. 2017 Sep 1;120:265-271. doi: 10.1016/j.watres.2017.04.064. Epub 2017 Apr 29.
Fungi are near-ubiquitous in potable water distribution systems, but the disinfection kinetics of commonly identified fungi are poorly studied. In the present study, laboratory scale experiments were conducted to evaluate the inactivation kinetics of Aspergillus fumigatus, Aspergillus versicolor, and Penicillium purpurogenum by free chlorine and monochloramine. The observed inactivation data were then fit to a delayed Chick-Watson model. Based on the model parameter estimation, the Ct values (integrated product of disinfectant concentration C and contact time t over defined time intervals) for 99.9% inactivation of the tested fungal strains ranged from 48.99 mg min/L to 194.7 mg min/L for free chlorine and from 90.33 mg min/L to 531.3 mg min/L for monochloramine. Fungal isolates from a drinking water system (Aspergillus versicolor and Penicillium purpurogenum) were more disinfection resistant than Aspergillus fumigatus type and clinical isolates. The required 99.9% inactivation Ct values for the tested fungal strains are higher than E. coli, a commonly monitored indicator bacteria, and within a similar range for bacteria commonly identified within water distribution systems, such as Mycobacterium spp. and Legionella spp.
真菌在饮用水分配系统中几乎无处不在，但常见真菌的消毒动力学研究甚少。本研究采用实验室规模实验，评估了游离氯和单氯胺对烟曲霉、变色曲霉和青霉的灭活动力学。然后，将观察到的失活动力学数据拟合到延迟 Chick-Watson 模型中。基于模型参数估计，测试真菌菌株达到 99.9%灭活所需的 Ct 值（在规定时间间隔内消毒剂浓度 C 与接触时间 t 的乘积积分），游离氯的范围为 48.99mg min/L 至 194.7mg min/L，单氯胺的范围为 90.33mg min/L 至 531.3mg min/L。来自饮用水系统的真菌分离物（变色曲霉和青霉）比烟曲霉型和临床分离物更具抗消毒性。测试真菌菌株达到 99.9%灭活所需的 99.9%Ct 值高于大肠杆菌，大肠杆菌是一种常用的监测指示菌，与水分配系统中常见的细菌（如分枝杆菌和军团菌）的范围相当。
