The BioSand Water Filter technology is owned by Pure Filtered Water Ltd. of Calgary, Alberta, Canada (www.purefilteredwater.com). The licensees of the plastic BioSand Water Filter technology are Triple Quest, Grand Rapids Michigan (www.hydraid.org) and Proshika, Bangladesh. All other plastic versions of the BSF are not licensed and from close examination of their designs are dangerous to use. Details on licensing opportunities that are still available may be obtained by contacting Pure Filtered Water Ltd.
The BSF should be cleaned using a vigorous surface agitation technique that does not involve penetrating the surface of the media more than 0.5 cm. Harrowing or the techniques will destroy the biolayer and ultimately the functioning of the filter. If correct cleaning procedures are used the BSF can be cleaned several times a day without loss of performance - at any time.
There is no difference in the performance of the LICENSED versions of the BioSand Water Filters and the variation of the concrete BSF described on this web site.
If the filters are designed, constructed, operated and cleaned according to principles described in this web site there should be no differences in performance. The heavier concrete filters are actually easier to build, less prone to breakage and not easy to steal. If weight is a problem the lighter versions might be an answer. Material costs are not significantly different. Material used in the construction of the concrete filter described in the Construction Manuals section is all locally available and inexpensive.
If weight is a problem then the obvious answer is use of the plastic filter.
If breakage is a problem, with any design, the cause is usually use of inferior materials in construction or rough handling during transportation.
Yes! This was clearly demonstrated in Nicaragua 15 years ago.
Yes, but only if the iron is not organically complexed. If the correct cleaning procedure is used the BSF may be cleaned several times a day without loss of performance.
Yes! Sometimes the BSF can remove arsenic without the addition of any additional chemicals or modification to the filter (published, peer reviewed papers report this research). If there is organic complexing special pre-treatment will be required.
The so-called "Kanshan" filter is NOT a variation of the BioSand Water Filter. This filter will lose its ability to remove arsenic even in the most ideal of circumstances.
The maximum flow rate is 400 litres per hour per square metre of surface sand surface as recommended by the World Health Organization.
No. The preferred material is crushed rock because the particles are not coated with organic materials that will foster the growth of bacteria and result in delayed realization of optimum filter performance - sometimes by several months.
Pure Filtered Water Ltd. of Calgary, Alberta, Canada owns the BioSand Water Filter technology (www.purefilteredwater.com).