Daily Archives: November 27, 2015

Bacteria Diversity Key to Slow Sand Filter Performance

Haig SJ, Quince C, Davies RL, Dorea CC, Collins G. The Relationship between Microbial Community Evenness and Function in Slow Sand Filters. MBio. 2015 Oct 13;6(5). pii: e00729-15. doi: 10.1128/mBio.00729-15.

Two full-scale slow sand filters (SSFs) were sampled periodically from April until November 2011 to study the spatial and temporal structures of the bacterial communities found in the filters. To monitor global changes in the microbial communities, DNA from sand samples taken at different depths and locations within the SSFs and at different filters ages was used for Illumina 16S rRNA gene sequencing. Additionally, 15 water quality parameters were monitored to assess filter performance, with functionally relevant microbial members being identified by using multivariate statistics. The bacterial diversity in the SSFs was found to be much larger than previously documented, with community composition being shaped by the characteristics of the SSFs (filter age and depth) and sampling characteristics (month, side, and distance from the influent and effluent pipes). We found that several key genera (Acidovorax, Halomonas, Sphingobium, and Sphingomonas) were associated with filter performance. In addition, at the whole-community level, a strong positive correlation was found between species evenness and filter performance. This study is the first to comprehensively characterize the microbial community of SSFs and link specific microbes to water quality parameters. In doing so, we reveal key patterns in microbial community structure that relate to overall community function.
IMPORTANCE: The supply of sustainable, energy-efficient, and safe drinking water to an increasing world population is a huge challenge faced by the water industry. SSFs have been used for hundreds of years to provide a safe and reliable source of potable drinking water, with minimal energy requirements. However, a lack of knowledge pertaining to the treatment mechanisms, particularly the biological processes, underpinning SSF operation has meant that SSFs are still operated as “black boxes.” Understanding these dynamics alongside performance-induced effects associated with operational differences will promote optimized SSF design, maintenance, and operation, creating more efficient and environmentally sustainable filters. Through a spatial-temporal survey of full-scale SSFs at various points of operation, we present the most detailed characterization to date of the functional microbial communities found in SSFs, linking various taxa and community metrics to optimal water quality production.

Australian Surface Temperature Records Corrupted

“It is nonsensical when there are thousands of older stations on record, that older records that are argued to require ACORN corrections should have a smaller sample than the “more reliable” largely uncorrected data of recent times.”

“In the 24 stations reviewed herewith, corrupted data continued decadaly as if no one was particularly interested back then, at a time before alarming climate change theories became more popular.” click here

Impact of Chlorination on Drinking Water Biofilm Bacterial Community

Mi Z, Dai Y, Xie S, Chen C, Zhang X. Impact of disinfection on drinking water biofilm bacterial community. Journal of environmental sciences (China). 2015 Nov 1;37:200-5. doi: 10.1016/j.jes.2015.04.008.

Disinfectants are commonly applied to control the growth of microorganisms in drinking water distribution systems. However, the effect of disinfection on drinking water microbial community remains poorly understood. The present study investigated the impacts of different disinfectants (chlorine and chloramine) and dosages on biofilm bacterial community in bench-scale pipe section reactors. Illumina MiSeq sequencing illustrated that disinfection strategy could affect both bacterial diversity and community structure of drinking water biofilm. Proteobacteria tended to predominate in chloraminated drinking water biofilms, while Firmicutes in chlorinated and unchlorinated biofilms. The major proteobacterial groups were influenced by both disinfectant type and dosage. In addition, chloramination had a more profound impact on bacterial community than chlorination.