You are here:
Insights into the Drinking Water Microbiome of a Pilot Scale Drinking Water Tank Simulator: implementing metagenomic approaches to understand the tank ecosystem
Citation:
Gomez-Alvarez, V. AND R. Revetta. Insights into the Drinking Water Microbiome of a Pilot Scale Drinking Water Tank Simulator: implementing metagenomic approaches to understand the tank ecosystem. WQTC 2019, Dallas, TX, November 03 - 07, 2019.
Impact/Purpose:
Finished water storage facilities are tanks, reservoirs, or other facilities used to store water that will undergo no further treatment to reduce microbial pathogens except residual disinfections. Their purpose is to meet peak demand, provide emergency storage (including for fire protection) and maintain distribution system pressure. Public health data has implicated finished water storage tanks in waterborne disease outbreaks (e.g. Legionnaires and Salmonellosis) across the USA. Storage tanks are vulnerable to contamination from animals, air, influent water and storage structure materials (i.e. leached chemicals). In addition, excess water retention time may cause depletion of disinfectant which creates an environment favorable to microbial contamination and enhanced disinfection by-product (DPB) formation. Sediment accumulation and biofilm formation enhance the growth and accumulation of pathogens, cause nitrification, physical blockage of valves and pipes, and release of particles into DWDS. Very little information is available about the microbial occurrence in storage tanks. It is important to understand the biotic and abiotic characteristics of these systems which amplify the potential public health risk relative to the DWDS. The purpose of this research is to determine how and why these opportunistic waterborne pathogens can persist within storage tank systems and how to implement effective water management plans to mitigate exposure risks to pathogens.
Description:
Finished water storage facilities are tanks, reservoirs, or other facilities used to store water that will undergo no further treatment to reduce microbial pathogens except residual disinfections. Their purpose is to meet peak demand, provide emergency storage and maintain distribution system pressure. Storage tanks are vulnerable to contamination from animals, air, influent water and storage structure materials (i.e. leached chemicals). In addition, excess water retention time may cause depletion of disinfectant which creates an environment favorable to microbial contamination. Sediment accumulation causes water quality degradation, including enhanced biological growth of pathogens, nitrification, and more rapid disinfectant decay. The emergence and development of next-generation sequencing technologies (NGS) made the analysis of the water microbiome much accessible and opens new perspectives in microbial ecology studies. NGS technology provide information on organism detection, identity, virulence- and antimicrobial-associated genes, and genetic relatedness. The current research evaluated the water microbiome in four 100-gallons tanks filled with 4 cm of drinking water storage tank sediment. The tanks were continuously fed with chlorinated municipal water amended with ammonia (2mg/L monochloramine) from a simulated drinking water distribution system (DWDS) and subjected to cycles of daily operational usage. Microbial communities were characterized based on 16S rRNA-encoding gene sequences of bulk water samples and sediment cores, of which two sections were examined (top and bottom). Results show that bacterial communities are highly diverse with evidence for spatial structuring of the population throughout locations and within episodes of disturbance, suggesting that the population is influenced by environmental conditions. NGS data allowed the reconstructions of several draft metagenome-assembled bacterial genomes, which harbored a diverse assemblage of virulence- and antimicrobial-associated genes. Very little information is available about the microbial occurrence in storage tanks. It is important to understand the biotic and abiotic characteristics of these systems which amplify the potential public health risk relative to the DWDS.