Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign , 205 N. Mathews, 3230 Newmark Lab, Urbana, Illinois 61801, United States.
Environ Sci Technol. 2014 Jun 17;48(12):6702-9. doi: 10.1021/es500494s. Epub 2014 Jun 6.
This study evaluated the role of physical and biological filter characteristics on the reduction of MS2 bacteriophage in biosand filters (BSFs). Three full-scale concrete Version 10 BSFs, each with a 55 cm sand media depth and a 12 L charge volume, reached 4 log10 reduction of MS2 within 43 days of operation. A consistently high reduction of MS2 between 4 log10 and 7 log10 was demonstrated for up to 294 days. Further examining one of the filters revealed that an average of 2.8 log10 reduction of MS2 was achieved within the first 5 cm of the filter, and cumulative virus reduction reached an average of 5.6 log10 after 240 days. Core sand samples from this filter were taken for protein, carbohydrate, and genomic extraction. Higher reduction of MS2 in the top 5 cm of the sand media (0.56 log10 reduction per cm vs 0.06 log10 reduction per cm for the rest of the filter depth) coincided with greater diversity of microbial communities and increased concentrations of carbohydrates. In the upper layers, "Candidatus Nitrosopumilus maritimus" and "Ca. Nitrospira defluvii" were found as dominant populations, while significant amounts of Thiobacillus-related OTUs were detected in the lower layers. Proteolytic bacterial populations such as the classes Sphingobacteria and Clostridia were observed over the entire filter depth. Thus, this study provides the first insight into microbial community structures that may play a role in MS2 reduction in BSF ecosystems. Overall, besides media ripening and physical reduction mechanisms such as filter depth and long residence time (45 min vs 24 ± 8.5 h), the establishment of chemolithotrophs and proteolytic bacteria could greatly enhance the reduction of MS2.
本研究评估了物理和生物过滤特性对生物砂滤器（BSF）中 MS2 噬菌体减少的作用。三个全规模的混凝土版本 10 BSF，每个都有 55 厘米的沙质介质深度和 12 升的负荷体积，在 43 天的运行时间内达到了 MS2 的 4 个对数减少。在长达 294 天的时间内，MS2 的减少量始终保持在 4 个对数至 7 个对数之间。进一步检查其中一个过滤器发现，在过滤器的前 5 厘米内，MS2 的平均减少量为 2.8 个对数，在 240 天后，病毒的累积减少量达到了平均 5.6 个对数。从该过滤器中取出核心沙样本进行蛋白质、碳水化合物和基因组提取。在沙质介质的前 5 厘米中，MS2 的减少量更高（每厘米减少 0.56 个对数，而其余部分减少 0.06 个对数），这与微生物群落的多样性增加和碳水化合物浓度的增加相一致。在上层，发现“Ca. Nitrosopumilus maritimus”和“Ca. Nitrospira defluvii”为优势种群，而在下层检测到大量与 Thiobacillus 相关的 OTUs。在整个过滤器深度上观察到了水解细菌种群，如 Sphingobacteria 和 Clostridia 等。因此，本研究首次提供了可能在 BSF 生态系统中减少 MS2 的微生物群落结构的见解。总的来说，除了媒体成熟和物理减少机制，如过滤深度和长停留时间（45 分钟与 24 ± 8.5 小时）外，化能自养生物和水解细菌的建立可以大大增强 MS2 的减少。
