MS2 Bacteriophage Reduction and Microbial Communities in Biosand Filters

Abstract

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.

Metagenomic analysis of rapid gravity sand filter microbial communities suggests novel physiology ofNitrospiraspp.

“…Archaea represented less than 1% of the filter community in both top and bulk samples (ISLBulk, 0.74 ± 0.10; ISLTop, 0.43 ± 0.02), consistent with previous studies examining the microbial communities in rapid gravity filtrations filters (Bai et al, 2013;Wang et al, 2014) and with a previous pyrosequencing analysis of the same community (Gülay et al, 2016). At the phylum level, Proteobacteria and Nitrospirae dominate bulk sample communities with a relative abundance of 18.93% ± 1.31% and 9.22% ± 4.72%, respectively; in the top of the filter these phyla were also dominant, with Nitrospirae most abundant (26.08% ± 0.94%), followed by Proteobacteria (14.47% ± 1.07%; Figure 1).…”

“…Ammonia-oxidizing archaea (AOA) have been detected in RSFs at low abundance (van der Wielen et al, 2009;Albers et al, 2015), although in a few examples they outnumbered ammonia-oxidizing bacteria (AOB; Wang et al, 2014;Nitzsche et al, 2015). However, the total AOB and AOA densities are often insufficient to explain the high abundances of Nitrospira relative to the ammonium oxidizers (reviewed in Gülay et al, 2016).…”

Microbial community composition of a household sand filter used for arsenic, iron, and manganese removal from groundwater in Vietnam

“…The high Nitrospira abundance found in this study corresponds to populations described in recent studies on biological water treatment and full-scale biofilters (Martiny et al, 2005;de Vet et al, 2009;Pinto et al, 2012;Feng et al, 2013;Li et al, 2013;Lautenschlager et al, 2014;Wang et al, 2014). Nitrospira represents the most widespread group of known NO 2 À -oxidizing bacteria found in many different aquatic and terrestrial environments, including Fe water-pipes, drinking water treatment systems, and wastewater treatment plants (Daims et al, 2001).…”

Microbial Dynamics of Biosand Filters and Contributions of the Microbial Food Web to Effective Treatment of Wastewater-Impacted Water Sources

“…The diversity and composition of the microorganisms in biosand filters have been characterized across a broad range of operating conditions. Most previous work on the microbial communities in biosand filters has focused on continuously operated systems representative of municipal-scale systems (5,8,13,(21)(22)(23)(24)(25), while only limited work focused on intermittently operated filters, typical of household-scale systems (26)(27)(28). This gap in our knowledge of the microbial communities in intermittently operated biosand filters is important given that many intermittently operated filters are implemented in conditions with less monitoring and often without posttreatment disinfection steps (2).…”

“…While filter performance has been shown to improve over time after start-up (9,14), most operational guidelines are driven by empirical observations (30), and the factors that impact microbial succession in these filters have not been well-studied. High variability between filter replicates and overall low levels of replication have also limited the conclusions that can be drawn from previous studies (15,28,31). In a study of two full-scale sand filters, Haig et al found that improvements in the performance of continuously operated filters over time correlated with increases in community evenness and the relative abundance of particular genera (including Sphingobium, Acinetobacter, and Halomonas) (9).…”