Pyrosequencing demonstrated complex microbial communities in a membrane filtration system for a drinking water treatment plant.

Microbial community composition in a pilot-scale microfiltration plant for drinking water treatment was investigated using high-throughput pyrosequencing technology. Sequences of 16S rRNA gene fragments were recovered from raw water, membrane tank particulate matter, and membrane biofilm, and used for taxonomic assignments, estimations of diversity, and the identification of potential pathogens. Greater bacterial diversity was observed in each sample (1,133-1,731 operational taxonomic units) than studies using conventional methods, primarily due to the large number (8,164-22,275) of sequences available for analysis and the identification of rare species.