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View Full Version : BioSand Water Filtration - 3rd world solutions for Prepping


redrex
11-04-2011, 12:20 PM
Ok, so I've recently had a moment of clarity. I've been looking for low cost solutions for prepping. Then one night I was watching a show on NatGeo about the problems in third world countries and how they deal with stuff like clean water and that's when it hit me. There are all sorts of programs out there, non profit types, that are trying to come up with cool, inventive solutions for the poor in developing countries. Like Low waste/high heat turbo cooking ovens, low water usage, bicycle powered clothes washing machines and easy to maintain and simple to use water filtration systems. So I'm going to start posting the ones that I've found and see what if any experience the rest of you have with them.

So the first item is BioSand Water Filtration! This is not a replacement for a small hand pump system that you would use in a BOB. This is for a long term or shelter in place system. I'm thinking of setting one up at home just to replace the Britta system that I use now.

Here is a basic setup:
http://upload.wikimedia.org/wikipedia/commons/thumb/7/72/BiosandFilter_Section.svg/220px-BiosandFilter_Section.svg.png

Here is a link to the Wikipedia article on this (http://en.wikipedia.org/wiki/BioSand_Filter)

I had brought this up in another discussion of water filter systems and AKjunkie was good enough to post this Link to a YouTube Video (http://www.youtube.com/watch?v=8LMWzb7DMS8&feature=related)

Who has tried this system, what are the pros and cons?

Librarian
11-04-2011, 12:39 PM
See also the article on slow sand filters - http://en.wikipedia.org/wiki/Slow_sand_filter

For a fixed location with a source of biologically suspect (as opposed to chemically contaminated) water, that sounds interesting.

Exocet5
11-04-2011, 4:33 PM
I would add a good pre-filter for water (in general) is a generic coffee filter. Helps to keep filter media cleaner both for hand-helds & this setup I would think.

Good topic.

damon1272
11-04-2011, 5:16 PM
The slow sand filtration is still used in parts of the US. Thing is is that it is slow. As librarian said. Great if you are bugged in.

EmptySkuLL
11-04-2011, 8:07 PM
Here is the link to the company in the US that is licensed to produce the plastic version of the BSF: http://www.hydraid.org/act/projects.html It looks like theyre geared more towards humanitarian donations to send these things where needed. They do have a "purchase" link, but you have to contact them for pricing.

According to the techinical papers on these things they still recommend post filtration disinfection. Also the only other downside is that it requires time to develop the biological "scum" layer of bacteria/ etc that is required to remove biological pathogens. Supposedly a newly installed filter removes around 60% biological contaminants, then after a few weeks it improves to 95% effectiveness after the bio layer grows. So this isnt going to be an immediate use filter, its geared more towards long term use... http://manzwaterinfo.ca/documents/guidance/BSF%20Performance%20Evaluation%20Jan%202009.pdf

Still, I would be interested in getting one or two of these things for long term SHTF use or to put in a Bugout location or campsite if the pricing is cheap enough (really, how much can what essentially ammounts to a fancy barrel and sand cost?).

Librarian
11-04-2011, 8:33 PM
Here's a decent description of details

http://www.oasisdesign.net/water/treatment/slowsandfilter.htm

This doc (www.nesc.wvu.edu/ndwc/pdf/OT/TB/TB14_slowsand.pdf) suggests an output rate of .15 gallon/minute per square foot of surface of the filter. A regular 23" diameter 55 gallon drum has about 2.9 sq ft of surface at the lid.

So, properly set up, one of these things in a 55 gallon drum should filter around 25 gallons per hour (I guess maximum).

Interesting.

Saym14
11-04-2011, 10:29 PM
you need carbon activation too. in any case I dont think it will kill as much bacteria as solar will. based on tests we did.

11HE9
11-04-2011, 11:09 PM
the only other downside is that it requires time to develop the biological "scum" layer of bacteria/ etc that is required to remove biological pathogens. Supposedly a newly installed filter removes around 60% biological contaminants, then after a few weeks it improves to 95% effectiveness after the bio layer grows. So this isnt going to be an immediate use filter, its geared more towards long term use...

I guess you could have one of these set up ahead of time, and just know that a alternate filter system will have to be used until the bio-sand set up is ready for use.

Or... have one tied into a rain water collection system :rolleyes:

redrex
11-07-2011, 3:50 PM
you need carbon activation too. in any case I dont think it will kill as much bacteria as solar will. based on tests we did.

Saym, I saw that you tested with those strips and I think it's cool to do your own tests. I know I'm going to but I don't think we can call your test "Conclusive". The World Health Organization's labs have done the same testing and while they do say that Solar (SODIS) is a viable means for purification it's entirely dependent on the season, the cloud cover and the temperature. And even in best case scenarios, ie. Summer, on a very clear and very hot day when placed on the right angled roof with the proper backing material you can only expect it to eliminate up to 80% of bacteria.

According to WHO, Biosand can remove 95-99% of bacteria and other organic pollutants. And it is the recommended solution for communities in need. The down side it that it does have some setup, about two weeks and its not portable.

Although I would agree with the suggestion to then run it through a carbon filter. Heck I'd also suggest that if the water were really bad to run it through cheese cloth first. And if you have the time, boil it for good measure ;)

And to the person who suggested hooking it up to a rain water source, thank you , excellent idea!

I have sent an email off to the humanitarian group who sells these to ask them if there is anyway to get these in the US. I'll let you know what I find out.