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high TDS and high fluoride levels in boreholes

Dear RedR Experts,

A friend of mine is reviewing some water boreholes drilled and equipped in Kenya. There are common threads emerging: high TDS and high fluoride levels.

What simple treatments are available to reduce these issues please?

I have heard of slow sand filters equipped with crushed cow bones being used to reduce fluoride levels but have no details. I am also wondering how much a slow sand filter reduces TDS levels ....but have nothing to hand on that topic.

Kind regards,

Steve

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Steve,

There are very many methods of reducing fluoride levels, but it would be best to stick with a proven method that is already in use in Kenya, is simple and doesn’t require chemical dosing. Searching the IRC WASH library (http://www.washdoc.info/) I found that the Catholic Diocese of Nakuru produce and re-activate bone char for fluoride removal, so that would seem to me to be the most appropriate line of enquiry (http://www.cathdnkenya.org/water.html). There is a paper on the viability of the bone char operation here:

http://www.washdoc.info/docsearch/title/173512

I hope this helps.

Regards,

Jeff

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Steve

You may want to look at the WHO document http://www.who.int/water_sanitation_health/publications/fluoride_drinking_water/en/index.html also look at the paper in Sandec News 7 (2006) at http://www.eawag.ch/forschung/sandec/publikationen/general/index_EN

Regards,

Brian

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Steve

Just to add TDS is by definition dissolved and capable of passing through a 2 micron filter. Pretty much anything that will go through a 2 micron filter will go straight through a slow sand filter too, so I wouldn't bank on any decrease in TDS with slow sand or bone char.

You generally need desalination for TDS removal. Blending with a low TDS source may be more economical if one is available.

Kind regards

Martin

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