Biosand Filters – The next step – Homemade biological filter

  • Guest


    Its an amazing breakthrough! Poor people are independently making their own biosand filters without moulds.
    Homemade biological filters are spreading by word of mouth like a good virus. The simplified design is freely available by googling for Homemade biological sand filters you arrive at relevant pages on the CMS web site. Spread the good news, safe water is now contagious.

  • Guest


    Excellent, just what we are looking for. The NGO I work for has been looking for a solution to contaminated water and have considered biosand filters. We have a policy to find solutions to problems that have the least possible outside intervention so as not to foster dependence on out side help. Manufacturing filters with the steal moulds even locally has its drawbacks, but now we can begin training users to make their own filters with the design on the CMS website.

  • Guest


    I am doing some research on viral designs. Can any one give me some figures as to, where is this idea working, how many families have made their own filters and how quickly is the idea spreading?

  • Guest


    This idea has done really well in Haiti. Look up an org. called \”Clean Water for Haiti\”…its a bit of a success story.

    -Chris Green

  • Guest



    I\’ve been doing a lot of searching for some homemade filter designs to use on a small-scale water project in Indonesia. I really like the CMS design, for all the reasons listed (primarily the ownership aspect for those using the filter).

    Unfortunately, people here have no history of making pots, clay or otherwise, and concrete (as suggested in their modifications) is expensive and difficult to get in remote villages (which puts the BioSand filter sadly out of reach). Ironically, plastic buckets in a variety of sizes are cheap and readily available.

    So my question to whoever may have an answer is, would substituting plastic buckets in the CMS design reduce the \”biological\” aspects of the filter? I\’m just wondering because clay (and even to a lesser extent, concrete) is a more natural substance than plastic.

    This is all still in the ideas phase, but I\’m thinking about trying to modify the CMS design with plastic buckets here. I also like the two-container idea because I have an idea to add some charcoal to the top bucket as a first step to filtration to deal with some colour and taste issues common to water here (with high tannin content). I realize charcoal should ideally be a last step but can\’t quite figure out how to get the charcoal on the bottom, seeing as it will need to be replaced more frequently than any other materials as the pores fill up.

    I\’d appreciate any advice/ideas/suggestions from anyone who happens to read this. This site seems to be frequented by some excellent technical minds! Thanks in advance.

    Lena Bunzenmeyer

  • Eric


    Hi Lena

    I can forward you a document about filters used in Nepal that were made from plastic. I don\’t believe that it makes any difference to the bacteriological efficiency, although if the sides are smooth there may be short-circuiting but I think that is an unproved theory as yet. In any case, you can always roughen the inner walls if needed to be sure.

    Email me at ericfewster @ if you would like this info.



  • Guest


    I also found the adaptations section on the CMS website very helpful. It nicely demystifies BioSand filter design and the home made biological sand filterthere has some sensible simplifications to the original design. I have had to think about how to teach people to make filters with plastic drums. One thing I would add is that when using plastic it is definitely worth scratching up the inside surface with horizontal scratches. A broken piece of brick is good for this. This is a simple enough addition to the design for it not to lose its potential to be spread virally by word of mouth, and a sensible precaution in case people start using plastic containers that are incredibly smooth inside.

    Using charcoal would help quality but as you know the carbon very gradually becomes obsolete. Users don’t notice the quality changing and most won’t change the charcoal. Smell and colour probably won’t be a problem as no doubt you will be teaching people that germs are invisible and that bio filters take out diseases. Lets face it even in the UK household carbon filters are notoriously forgotten about and most are not changed as often as they ort to be.

  • Guest


    Thanks Chris

    From the website, “Clean water for Hati” seem to be manufacturing filters with the steal moulds, but this thread is about training users to make their own filters with out the need for steal moulds so as to avoid fostering unnecessarily dependence on out side help. Do they do this too?

  • Guest


    Does anyone know of a Biosand filter project in Afghanistan?


  • Guest


    Have you tried contacting SERVE?

  • Guest


    Would this work in the UK or is it too cold.

  • Guest


    I am developing a modular biosand water filter made from 2-gallon and 5-gallon
    plastic paint buckets. The buckets are made of food-grade (number 2) polyethylene
    and are the same buckets you can find at most hardware stores worldwide. I believe
    my modular water filter meets all of the critical design requirements of the
    biosand filters developed by the CAWST.

    Please visit my work-in-progress page, link below, for details.

    I am also developing some scaled down filters to be used as rapid deployment
    options for treating water in desperate situations (Haiti and Pakistan).

    Please take some time to examine these DIY water filters.

    Please note, I am not selling anything. I am freely sharing information
    with anyone concerned with the safe water crisis.

    Your comments will be highly regarded.


  • Moz


    The material referred to for this post is now found at

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GuestBiosand Filters – The next step – Homemade biological filter