Operational performance, biomass and microbial community structure: impacts of backwashing on drinking water biofilter

Abstract

Biofiltration has been widely used to reduce organic matter and control the formation of disinfection by-products in drinking water. Backwashing might affect the biofilters' performance and the attached microbiota on filter medium. In this study, the impacts of backwashing on the removal of dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and N-nitrosamine precursors by a pilot-scale biological activated carbon (BAC) filtration system were investigated. The impacts of backwashing on biomass and microbial community structure of BAC biofilm were also investigated. Phospholipid fatty acid (PLFA) analysis showed that backwashing reduced nearly half of the attached biomass on granular activated carbon (GAC) particles, followed by a recovery to the pre-backwashing biomass concentration in 2 days after backwashing. Backwashing was found to transitionally improve the removal of DOC, DON and N-nitrosamine precursors. MiSeq sequencing analysis revealed that backwashing had a strong impact on the bacterial diversity and community structure of BAC biofilm, but they could gradually recover with the operating time after backwashing. Phylum Proteobacteria was the largest bacterial group in BAC biofilm. Microorganisms from genera Bradyrhizobium, Hyphomicrobium, Microcystis and Sphingobium might contribute to the effective removal of nitrogenous organic compounds by drinking water biofilter. This work could add some new insights towards the operation of drinking water biofilters and the biological removal of organic matter.

Influence of substrate type on microbial community structure in vertical-flow constructed wetland treating polluted river water

“…Microorganisms from Proteobacteria might be involved in the biodegradation or biotransformation of numerous organic compounds in natural or manmade ecosystems Liao et al 2013aLiao et al , 2015Liu et al 2014a;Zhang et al 2014). The dominance of Proteobacteria has been found in natural wetlands (Ansola et al 2014;Liu et al 2014b), wastewater CW systems (Ansola et al 2014;Bouali et al 2014;Huang et al 2013), and biofilters treating surface water (Feng et al 2013a;Liao et al 2013b).…”

“…High-throughput sequencing technology is a highly efficient tool for identifying the profile of complicated microbial community (Liao et al 2015;Wang et al 2015a, b;Yang et al 2015), and can provide a new opportunity to resolve the microbial assemblage of CW biofilm and systematically investigate its links with operational and environmental conditions (Ansola et al 2014;Arroyo et al 2015;Zhong et al 2015). Due to its relatively low costs and great throughput, Illumina sequencing has been applied to profile microbial communities in various natural and man-made ecosystems Shi et al 2014;Sun et al 2015;Wu et al 2015;Yang et al 2014;Zhang et al 2015).…”

Distribution of sediment bacterial and archaeal communities in plateau freshwater lakes

“…The recently developed Illumina MiSeq platform can yield more detailed information of microbial community with greater throughput but less cost (Caporaso et al 2012;Nelson et al 2014). Illumina-based sequencing has found applications in characterizing the bacterial community in various natural and man-made environments, such as drinking water biofilter (Liao et al 2014), biofilm on drinking water distribution pipe (Wu et al 2014), anaerobic digestion sludge (Yang et al 2014), tropical rainforest leaf litter , river water (Staley et al 2013), soil (Rubin et al 2013), and mangrove wetland sediment (Jiang et al 2013). In addition, Illumina-based sequencing has also had several applications to characterize archaeal community in natural and man-made environments, such as fluid and sediment at a shallow marine hydrothermal site (Lentini et al 2014), biogas-producing and phenol-degrading bioreactor (Ju and Zhang 2014), and reservoir sediment (Zhang and Huang 2013).…”

From source to filter: changes in bacterial community composition during potable water treatment

“…But, biofilter efficiency depends not only on the properties of the filter medium, such as porosity, degree of compaction, and water retention capacity, but also its capacity to host and sustain a robust microbial population that can enhance contaminant removal (Basu et al 2016;Song et al 2015;Srivastava and Majumder 2008). Microbial communities that establish within the filter metabolize and precipitate contaminants through biodegradation and oxidation-reduction reactions (Zhu et al 2010), and are a function of the diversity of the community from which they are drawn, as well as substrate availability (Basu et al 2016;Curtis and Sloan 2004;Liao et al 2015;Liao et al 2016). The subsequent performance of the filter communities appears to be influenced by a multitude of factors that include species richness, dynamics, evenness, and functional redundancy of the bacterial community (Basu et al 2016;Boon et al 2011;Briones and Raskin 2003;Fish et al 2015), making an understanding of the composition and interplay of microbial communities in source water, as well as within biofilters essential for enhancing drinking water treatment and water source management.…”