Department of Civil and Environmental Engineering, University of Missouri, E2509 Lafferre Hall, Columbia, MO 65211, USA.
Water Res. 2013 Sep 1;47(13):4507-18. doi: 10.1016/j.watres.2013.05.014. Epub 2013 May 20.
Water and wastewater filtration systems often house pathogenic bacteria, which must be removed to ensure clean, safe water. Here, we determine the persistence of the model bacterium Pseudomonas aeruginosa in two types of filtration systems, and use P. aeruginosa bacteriophages to determine their ability to selectively remove P. aeruginosa. These systems used beds of either anthracite or granular activated carbon (GAC), which were operated at an empty bed contact time (EBCT) of 45 min. The clean bed filtration systems were loaded with an instantaneous dose of P. aeruginosa at a total cell number of 2.3 (± 0.1 [standard deviation]) × 10(7) cells. An immediate dose of P. aeruginosa phages (1 mL of phage stock at the concentration of 2.7 × 10(7) PFU (Plaque Forming Units)/mL) resulted in a reduction of 50% (± 9%) and >99.9% in the effluent P. aeruginosa concentrations in the clean anthracite and GAC filters, respectively. To further evaluate the effects of P. aeruginosa phages, synthetic stormwater was run through anthracite and GAC biofilters where mixed-culture biofilms were present. Eighty five days after an instantaneous dose of P. aeruginosa (2.3 × 10(7) cells per filter) on day 1, 7.5 (± 2.8) × 10(7) and 1.1 (± 0.5) × 10(7) P. aeruginosa cells/g filter media were detected in the top layer (close to the influent port) of the anthracite and GAC biofilters, respectively, demonstrating the growth and persistence of pathogenic bacteria in the biofilters. A subsequent 1-h dose of phages, at the concentration of 5.1 × 10(6) PFU/mL and flow rate of 1.6 mL/min, removed the P. aeruginosa inside the GAC biofilters and the anthracite biofilters by 70% (± 5%) and 56% (± 1%), respectively, with no P. aeruginosa detected in the effluent, while not affecting ammonia oxidation or the ammonia-oxidizing bacterial community inside the biofilters. These results suggest that phage treatment can selectively remove pathogenic bacteria with minimal impact on beneficial organisms from attached growth systems for effluent quality improvement.
水和废水过滤系统通常会容纳病原菌，必须将其去除以确保水的清洁和安全。在这里，我们确定了模型细菌铜绿假单胞菌在两种过滤系统中的持久性，并使用铜绿假单胞菌噬菌体来确定它们选择性去除铜绿假单胞菌的能力。这些系统使用无烟煤或颗粒活性炭（GAC）床，空床接触时间（EBCT）为 45 分钟。清洁床过滤系统以总细胞数为 2.3（±0.1[标准差]）×10（7）个细胞的瞬时剂量加载铜绿假单胞菌。立即剂量的铜绿假单胞菌噬菌体（1 毫升噬菌体储备液，浓度为 2.7×10（7）PFU（噬菌斑形成单位）/mL）分别导致清洁无烟煤和 GAC 过滤器中流出物铜绿假单胞菌浓度降低 50%（±9%）和>99.9%。为了进一步评估铜绿假单胞菌噬菌体的效果，用含有混合培养生物膜的合成雨水通过无烟煤和 GAC 生物过滤器。在第 1 天接种铜绿假单胞菌（每个过滤器 2.3×10（7）个细胞）后的 85 天，在无烟煤和 GAC 生物过滤器的顶层（靠近入口端口）分别检测到 7.5（±2.8）×10（7）和 1.1（±0.5）×10（7）个细胞/g 过滤介质中的铜绿假单胞菌细胞，表明生物过滤器中病原菌的生长和持久性。随后以 5.1×10（6）PFU/mL 的浓度和 1.6 mL/min 的流速进行 1 小时的噬菌体剂量，将 GAC 生物过滤器和无烟煤生物过滤器内的铜绿假单胞菌去除了 70%（±5%）和 56%（±1%），流出物中未检测到铜绿假单胞菌，同时对生物过滤器内的氨氧化或氨氧化细菌群落没有影响。这些结果表明，噬菌体处理可以选择性地去除病原菌，对附着生长系统中的有益生物的影响最小，从而改善出水质量。
