title: Integrated metagenomic and physiochemical analyses to evaluate the potential role of microbes in the sand filter of a drinking water treatment system.
abstract: While sand filters are widely used to treat drinking water, the role of sand filter associated microorganisms in water purification has not been extensively studied. In the current investigation, we integrated molecular (based on metagenomic) and physicochemical analyses to elucidate microbial community composition and function in a common sand filter used to treat groundwater for potable consumption. The results revealed that the biofilm developed rapidly within 2 days (reaching ≈ 10(11) prokaryotes per gram) in the sand filter along with abiotic and biotic particulates accumulated in the interstitial spaces. Bacteria (up to 90%) dominated the biofilm microbial community, with Alphaproteobacteria being the most common class. Thaumarchaeota was the sole phylum of Archaea, which might be involved in ammonia oxidation. Function annotation of metagenomic datasets revealed a number of aromatic degradation pathway genes, such as aromatic oxygenase and dehydrogenase genes, in the biofilm, suggesting a significant role for microbes in the breakdown of aromatic compounds in groundwater. Simultaneous nitrification and denitrification pathways were confirmed as the primary routes of nitrogen removal. Dissolved heavy metals in groundwater, e.g. Mn(2+) and As(3+), might be biologically oxidized to insoluble or easily adsorbed compounds and deposited in the sand filter. Our study demonstrated that the role of the microbial community in the sand filter treatment system are critical to effective water purification in drinking water.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, People's Republic of China.
authors.forename: Yaohui
authors.initials: Y
authors.lastname: Bai
authors.forename: Ruiping
authors.initials: R
authors.lastname: Liu
authors.forename: Jinsong
authors.initials: J
authors.lastname: Liang
authors.forename: Jiuhui
authors.initials: J
authors.lastname: Qu
mesh_terms: D001483:Base Sequence; D018441:Biofilms / Q000254:growth & development*; D002681:China; D016000:Cluster Analysis; D019295:Computational Biology; D060766:Drinking Water; D005374:Filtration / Q000295:instrumentation*; D060587:Groundwater / Q000737:chemistry / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D054892:Metagenome / Q000235:genetics*; D019216:Metals, Heavy / Q000032:analysis; D058977:Molecular Sequence Annotation; D008969:Molecular Sequence Data; D056951:Photoelectron Spectroscopy; D010802:Phylogeny; D020560:Proteobacteria / Q000145:classification / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012822:Silicon Dioxide; D018508:Water Purification / Q000295:instrumentation*
chemical_list: D060766:Drinking Water; D019216:Metals, Heavy; D012822:Silicon Dioxide