- Bank filtration
Bank filtration is a type of
filtration that works by passing water to be purified for use asdrinking water through thebank s of a river or lake. It is then drawn off by extraction wells some distance away from the water body. The process may directly yield drinkable water, or be a relatively uncomplicated way of pre-treating water for further purification.Efficiency
Most 'normal' contaminants (microbial organisms and inorganic or organic pollutants) will be removed by bank filtration, either because they get filtered out by the sand/earth of the bank, or because the passage time (which may be days or potentially weeks) is sufficient to render them inactive. [http://www.wrrc.hawaii.edu/bulletins/2000_08/filtration.html Bank Filtration for Water Treatment] (from a
Water Resources Research Center ,University of Hawaii , Manoa, bulletin, 2000/08. Accessed 2008-03-24.)] Research has also shown that the removal efficiency depends not only on the contaminant, but also on the "hydraulic and chemical characteristics of the bottom sediment and the aquifer, the local recharge-discharge conditions, and biochemical processes".There have been indications that some pharmaceutical compounds (medical drug traces from human use) may not always be sufficiently removed by bank filtration, and that in areas with substantial contamination of this type, additional treatment may be needed." [http://www.ucowr.siu.edu/updates/pdfn/v120_a2.pdf Occurrence and fate of pharmaceuticals during bank filtration] " - Heberer, Thomas et al;
University of Berlin /United States Geological Survey , ca 2001]History
The process has been in use in Europe, especially in Germany along the Rhine and later in Berlin, since the 1870s. Major facilities also exist in many other countries, including the United States, where Nebraska is leading in the use of such facilities.
See also
*
Biofilter
*Folkewall
*Trickling filter References
External links
* [http://www.bankfiltration.org/ BankFiltration.Org] (German website promoting advantages of and research into bank filtration)
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