Quick and easy way to purify water in an unconnected African Village

Hi everyone,

I would like to start a permaculture farm in the native village of my father which is around 40km from Bamako, the capital of Mali Western Africa.
At the moment there is no drilling well, only a small well with very questionable water : Each time I've drunk some my tummy has felt it. Some time you end up with frogs or instects of all sorts in your water.

I plan to settle down there next year, but wonder what would be the easiest way for me to purify the water for drinking uses. Indeed, for a few months I might not have a drilling well so I need to find a way tu purify some of the current well water.

Of course this being a isolated village, there is almost no electricty so is there any low tech possibilities for me to clean the well water ?

I heard Clay was efficient in cleaning well water, but finding enough clay for a day to day use, might not be so easy.

Any other ideas ?

Many thanks,

Eli

The question of scale is a big one, and of materials at hand. The other issue is for what purpose. If you need it all to be purified so it is all safe to drink, I don't know if there's a way other than boiling or a chemical solution (I think most survival guides list potassium permanganate, but I might be getting that wrong). UV light will kill most pathogens in clear water, so if you had transparent containers filled with water in a darkly-coloured sunny spot, they might do some of the job, but I don't know if I would trust that without some kind of rudimentary test.

I think the real way to purify your water is something like the following: Find yourself stones, preferably of different sizes. Lots of them. Either sort them by hand or make a rudimentary seive of sorts to help separate the big from the medium and the small. You also will need to find some clean sand, also of different grades if you can, coarse to fine. Finally, you need a perforated pipe or tube capable of keeping an air channel under ground while letting water through. If this isn't available, in a large enough hole, you could make an inner well wall designed to let water trickle through, but this would be more difficult.

Before you actually execute this plan, make sure you talk with people in your area who might have seen this kind of thing for problems they'd encountered specific to your area and climate. I'm sure anyone with more experience than me will note any problems with my plan and suggest safer alternatives or tweaks, so keep in mind that I am making these suggestions without knowing the variables specific to your situation.

You want to make a gravel and sand filter for your well. Dig it out as well as you can, preferably until you've found some kind of natural bottom, a clay layer or bedrock, but you need some depth. The idea is to wrap your pipe or tube in something like a cloth barrier to keep fine particles out. Then you begin backfilling your well from the outside in, making sure the fill with the largest particles is to the outside, getting smaller as they approach the particle barrier. Incidentally, if you can get or make lots of charcoal (biochar), you could add this as the layer between tiny pebble fill and coarse sand, and it would act to trap and filter out extremely small contaminants. Your fine sand layer would be the last one, unless you have clay that you can powder and add, but I would be concerned with free clay particles, or with them swelling and sealing out the water you want to pass through your layers into your new tube well.

This idea is a lot quicker and easier if you have some salvaged materials to reuse, and has to be tailored to the environment, but the idea of a sand filter is time tested.

It just occurred to me that you could, depending on materials, leave your current watersource as it is and build a filter using the same principles and pour water through it, but I could see such a setup needing two or three drums of any size, but 55 gallon ones would be best for lots of water, and you'd need to fill a top reservoir to let gravity pull it through a filter of some sort (probably stones, pebbles, biochar preferably, two or three grades of sand if possible, and your filter cloth), but once you were to build that, all you'd have to do is keep filling it, and gravity would keep pulling the water through.

I would love to know what ways, other than drilled wells, people in your area traditionally used to purify their water. I would be surprised if there weren't clever solutions there.

Good luck, and please keep us posted!

-CK

Dear CK,

Thank you so much for the amazing post.
I like the idea of setup with two or three drums.

I think I'll try it this way. Short term wise it should be enough.

You're right though, I should also ask for the traditional way people have been purifying water in the area. I'll let you know when I know more :p

Thank you once again

Eli

A very miniature version of an artificial wetland, might serve your needs. If you are able to get a sheet of rubber or some thick, flexible plastic, a depression could be made in the soil, near your water source. You would pour the dirty water, into one end of the system, and retrieve much cleaner water, that has traveled through the sand and soil of your little wetland. This assumes that you have control over that area, so that others don't pollute your water in some way. Chicken wire, or some other fencing, could keep it from becoming a watering hole for wild creatures. Once this water is relatively clean, it could be run through a filter made from charcoal. If the retrieval well, we're quite well sealed, it would not become home to mosquitoes. I think it would be best to never have water sitting on the surface, but always beneath a layer of coarse gravel, or other medium that is not attractive to mosquitoes.

Check out artificial wetlands and constructed wetlands, on Google Images. I'm sure that a miniature version as little as 2 meters long, would go a long way as the beginning stage of water purification. Rice, water chestnuts, lotus or other edible plants that don't mind being waterlogged, would turn your purification system into a garden.

If I was in your position, I would build a DIY filter like Chris Kott has described, but then pass it through a professional (gravity fed) water purifier just to be absolutely certain. By using this two-stage system, your own filter should extend the life of the professional filter and make maintenance costs lower.

Yeah, or that. I love your approach, Dale. It would definitely be awesome if it were a long-term solution, and designing a reed-bed garden filtration system would definitely be that. And realistically, what you're talking about, with the exception of the impermeable material, could effectively be sourced on-site, providing that the whole thing be topped with coarse gravel.

Though I wouldn't call creating an artificial wet land quick and easy, I think that it would be good complement to any permacultural setup after the immediate needs of hydration are met, especially with an adjacent orchard or other perennial-centric garden. That's the kind of thing that kicks off different microclimates where there once was no variation.

-CK

Do a google search for "slow sand filter" and study several implementations of this design. If you used the wetland as your primary treatment, the water could then go through a slow sand filter and very likely be potable at the end. For polishing, you could follow with charcoal, and if you're still concerned about nasties you could use UV.

For what it's worth, I differ with Chris's design above (and the first few sand filters made were more or less like what he describes). It's basically the reverse of how you want to do it: big rocks or urbanite for the bottom layer where the perforated pipe (and no cloth) resides, then smaller rocks above that, then coarse sand, and finally fine sand. Doing it this way sets up the biofilm in the upper layer of the sand and when it's established it can trap really small stuff, all the way down to some viruses. Leaving out cloth barriers also removes a likely early point of failure. The first sand filter I constructed had geotextile separating the various grades of material, and the stuff blocked up within two weeks.

Actually, I like the idea of, providing access and a reasonable amount of control over any improvements, making Dale's artificial wetland a transitionary area somewhere connected to or adjacent to the existent well, especially if its more of a large seep water hole. That could terminate at the beginning of the artificial wetland. I would make it snake back and forth within the trench using baffles of any kind, even earth shaping under the membrane, in order to lengthen the path of the water. The very end of the trench could literally end with the filter of progressively smaller particles and biochar that end in that well tube. It occurs to me that if the system were the depth of a barrel or drum, you could use that for your well and cap it, perforating the one side that forms the end wall of the trench.

-CK

I'll bet that the final plan, will be somewhat related to what Eli can find. Things that we take for granted here, can be very difficult to source in other parts of the world. The one thing that seems to be in no short supply, is plastic waste.

I have friends in Kenya who only consume water that has been through a commercial filter, because of the risk of Cholera. Those who can't afford it, drink tap water. All of the systems described, would greatly reduce pathogens, if not eliminate them. People whose families have lived in those areas for a long time, may experience no difficulty from low-level contamination. Most of us in the west, drinking the same water, would get a horrible case of diarrhea and the dehydration that comes with that. For long term treatment, something like what I have described, followed by filtration similar to what Chris described in his first post, would surely make the water safer.

Yeah, Dale, I was thinking along the same lines. Systems that work without many manufactured parts. I figured 55 gallon fuel drums might be available, or the food storage variety in plastic. It didn't occur to me to think about plastic sheeting.

So would a shallow seep into dark pebbles into the sand filter before the barrel act as a UV pathogen killer?

-CK

I doubt that there would be much UV pathogen killing going on. But, almost everyone can come up with a big glass jar. After the water runs through filtration and is gathered, I wonder if it could simply be bottled and placed in the Sun for a day or two. This might require the acquisition of a few jars. Sunlight is a great sterilizer , and that part of the world has no shortage. The water would also undergo a very large temperature swing, during those couple days of sterilization.

I love the method suggested by Dale. Sterilizing water in clear jars is my preferred method when camping. It has a long and prestigious history, and is recommended by the World Health Organization and the Red Cross. It works even better for me with a high altitude desert climate.

http://www.sodis.ch/methode/index_EN
http://blogs.discovermagazine.com/80beats/2012/05/16/to-disinfect-water-cheaply-just-add-sunlight-and-salt-or-lime-juice/

Lots of good information given above.

I have an engineer friend who took a course to go work for Doctors Without Borders (Médecins Sans Frontières).  He gave me his text:  Engineering in Emergencies to brainstorm my own potential water intake on my creek.

For what it's worth, I differ with Chris's design above (and the first few sand filters made were more or less like what he describes). It's basically the reverse of how you want to do it: big rocks or urbanite for the bottom layer where the perforated pipe (and no cloth) resides, then smaller rocks above that, then coarse sand, and finally fine sand.

 

This is pretty accurate to Phil's credit.  The larger rocks are near your outlet pipe.  The method that Chris K described originally is a possible solution, but is more prone to being clogged by bacterial agents or clays/silts, as is using any type of cloth near the pipe.  A person can also put some larger round rocks near and on the surface of the finer material to good effect in aiding water penetration from the surface.  Many alternating layers of charcoal and sand (in the fines area) are highly effective at screening bacteria, and fine particulate.  The less standing water the less chance of harmful microbes getting involved.  If you are going to have standing water, then you want diverse habitat/species to allow a rich system of aerobic biology to flourish.

I'll give my permacultural perspective at the same time as adding some stuff from this text.  

The engineering text does not go into swamp (aquatic plant centered) systems of filtering... but from what I have read of gray water treatment, the more (non toxic)aquatic or semi aquatic plants you have in the upper portion, the more biological filtration, and the more shade.  With shade, you get cooler water, which has less bacteria.  Planting trees uphill of your spring, and on the sunward side are very helpful in increasing natural water pumping and shading the site respectively. You have to make a judgement call on the amount of plants, though, in the water itself, in relation to the amount of water flowing from your source at it's minimum flow times.  Sometimes the volume of plants will be too high for the amount of water, thus drinking all (or too much) of what is there.  Reforestation of the area upslope is the best way to charge the underground zone that is feeding your spring, while swales and upslope pits are secondary to but possibly in concert with the planting of trees.  

Your goal is to have water flowing, continuously, out of your spring, in as clean a state as possible.  If you have gravity as your ally then use it to create oxygenating water falls into gravel catchments, shading the splash zones from evaporation, and/or create flow forms that oxygenate via reversing flow directions in each consecutive downhill mini pool.

In the book they show the best way to create a cheap outlet pipe (as perforated pipe is not often available in emergency zones, but regular straight up pipe is almost always somewhere around).  Take any thick walled pipe, and cut it transversely (not longitudinally) with a hacksaw. Longitudinal (lengthways) cuts can cause the pipe's slots to collapse under compressive forces, particularly with thinner walled pipes.  

A regular hacksaw creates slots around 1mm.  

Slots can be cut into three 'sides' of a pipe, separated into thirds on the circumference.  It is recommended that slots from each of the three have a minimum of 20mm's of solid pipe in between.  Down the length of the pipe, an image in the book shows a pipe  with 11 slots hacksawed across the pipe in a space of 300 mm, with a (stabilizing) gap of 40mm between that and the next 300mm section of slots, then the pipe would be rotated 1/3rd and leaving a 20mm stabilizing spine, cut again into the surface with a series of 11 slots in 300mm's.  It looks like a three inch pipe in the drawing, which shows a cross section with three slotted sections cut in with three 20mm solid spines.  

It is stated clearly that a longer pipe is much more effective at increasing water flow, than using a wider diameter pipe.      

Of rocks, round rocks allow more water flow than angular rocks (which, by nature, lock their flat surfaces together/creating a potential seal), and so round rocks are what you want near your pipe.  You want flow, but you want a filter.  So you have layers of fine material (such as sand and charcoal) at the surface of your system with round rocks increasing in size toward your drain pipe.  The biological filter is in your top layers.  The water flows into your top layers and is first cleaned by the biology (which will improve as your system develops), as well as the physical barrier of the sands and char.  It might be wise to inoculate your char with beneficial microbes which will help to inoculate the entire surface system so that it deals with any harmful bacteria, and other macro beings as effectively as possible.

Whatever the case, you want your system to flow and, if stopped at a tap, the tap not be contaminated.  Good signs (with graphics instead of words), and/or appropriate education, are imperative to keeping your water source, and tap, clean.  Clean hands, are important here.  A hand washing program will go a huge way to preventing the spread of disease, and the establishment of a stable water gathering location/tap.

The system can be doubled, so that you are dumping water from one swamp filter into a second one, thus creating a much higher chance of eliminating the harmful biological agents.

As mentioned, any type of fence to keep domestic animals (or people) out of the spring source area is a huge gain.  

It still may be necessary to purify the water, especially at the beginning stages of your system.  The use of bright sunlight in clear glass is the best solution, and should be used for drinking purposes, at least until the water has been tested as pure.  Again some graphic signs would be appropriate to encourage sun purifying in the appropriate way.

One of the other super important things to go along with this, is a proper system of dealing with human waste; and again, proper hand sanitation in that system.  The combination of a clean water system and a clean human waste system will have massive gains for the health of the village in question.

I will read more of this book and get back to this thread if I can glean more info that I think is pertinent.

Good luck with your very noble project!  Please post of your system on this thread.            

Guys, guys, we are only talking about a quantity of water for drinking ! How much does a family drink in a day, maybe a big family may consume 20 litres?

This is just a very small scale purification project of a small drum, or jar with the charcoal and sand filters, adn a little tap so it can be drawn off cleanly. We are talking of using an existing well, you throw a bucket down and collect your 20L a day and don't forget to keep the containers clean too, nothing complicated. then you put the filtered water in a nice big earthenware pot in the corner of the kitchen that allows the water to evaporate and it cools a little too, enjoy!

check this out...

http://www.theprepperjournal.com/2013/07/11/100-year-old-way-to-filter-rainwater-in-a-barrel/
https://youtu.be/ZC7A3621_hg
Here's a couple ideas

I haven't seen a Berkey gravity filter mentioned. Its the most economical way to have safe water. Period.
Pre filter with something low tech as best you can but using a Berkey or equivalent is  probably the best route to maintain your health.

I think people were assuming limited resources were available and we could not just go buy a Berkey. I think a 12 litre Berkey would do the trick and can clean some pretty bad water. I think some pathogens would still get through. If you dug down low enough, I'd say at least 7 meters pathogens would not be so much of an issue. Also sealing the well is very important to keep pests out.

I would not advise putting charcoal around your well pipe as it would likely break down into dirt. If you are going to do that, do it at the surface.

Also you can do a shallow well with a driven well screen. I live in an area where the ground water is pretty shallow and people are able to get clean enough water, at less than 4 meters.

The issue with bugs and frogs is probably because the well isn't sealed. I dug an 8 meter well and forgot to seal because I had to go work on something else and it got filled with frogs and rodents when the weather changed... Cleaning that out was wonderful...

If you are looking for quick, drive what is called a point well head. You need to have a high water table for this. Digging a drilled well by hand with a hand auger is doable, it only took me a week of evenings, so about 24-30 hours for an 8 meter well. Get a clam shelled auger that will accept extra pipe for extension.

 All this talk on filtering household drinking water makes me want to chime in with my personal favourite - the Lifesaver Jerrycan 20000 L. Expensive? Yes and no. It's a lot cheaper than bottled water in any size bottle - I have never replaced the filter, which can filter down to 2 microns of contaminants. This includes viruses. Expensive? Wait till the filters need replacement. Since I am basically the only person using this device, and I am filtering sometimes questionable well water, I expect it to last several years. Just to be on the safe side, I also ordered a replacement filter and carbon filters, which can also be shipped with a foil covering for storage. I decided to filter my water after a bout of diverticulitis almost landed me in hospital several years ago. So far, so good. There is a 40,000 litre jerrycan available as well, but I'd think that was a very large family size.

Certainly the filtration devices mentioned above will strain out the visible contaminants, but you can't see bacterial/viral/chemical pollutants. The Lifesaver (registered trademark) knocks out 2 of those 3 items for sure. And as my tap water gets tested regularly,, I take it up a notch. I often think it is a far better choice than importing water at a horrendous price in plastic pollution or in human labour to produce wells of uncertain drinking value. Of course, water has to be available to be filtered.

It will probably take a combination of several techniques to get clean water. You probably start best with indexing what you have available locally and what you need to bring in.

These links you might find usefull. In its most basic form, you just need clear plastic bottles to produce good drinking water. But it's  probably safer in the long run to provide everybody nearby with clean water. If nobody near you has a waterborne disease they can not infect you or the water nearby. Remember Certain minerals may cause diarrea if present in drinking water. Others are toxic in the long term - arsenic f.e. There is lots of info on this on the net. If brick, sand, clay and charcoal are available you can get most contaminants out of your water.

If available a solar cooker is a fast way to kill pathogens in groundwater.

An interesting system was developed in Venice Italy - see the links at the bottom below. They are more sofisticated but if you combine this with uv desinfection, you should have a safe system that takes little maintenance and little or no electricity.


https://en.wikipedia.org/wiki/Solar_water_disinfection

https://www.youtube.com/watch?v=Oqu2mcIuK90

https://www.wikihow.com/Sterilize-Water-With-Sunlight

https://www.rd.nl/vandaag/buitenland/em-arme-indonesi%C3%ABrs-laten-water-zuiveren-door-zon-em-1.1184188

https://www.technologyreview.com/s/526231/a-low-tech-water-filter/

http://www.venipedia.org/wiki/index.php?title=Well

http://www.venipedia.org/wiki/index.php?title=Wellhead

Dale Hodgins wrote:I doubt that there would be much UV pathogen killing going on. But, almost everyone can come up with a big glass jar. After the water runs through filtration and is gathered, I wonder if it could simply be bottled and placed in the Sun for a day or two. This might require the acquisition of a few jars. Sunlight is a great sterilizer , and that part of the world has no shortage. The water would also undergo a very large temperature swing, during those couple days of sterilization.

Glass is less effective than PET plastic bottles (often readily available free). Some glass blocks very nearly all UV light.
http://modernsurvivalblog.com/health/purify-water-with-sunlight-glass-or-plastic/

Hi, I've used a ceramic water filter in Nicaragua for 1 year, and I've been very happy about it. The one I had was coated with colloidal silver, to increase efficiency. Now I'm going to live off grid in Colombia, and fortunately I will be able to buy one here again.

This is where I bought it in Nicaragua: https://www.filtronnica.com/english/
And some general information: https://en.wikipedia.org/wiki/Ceramic_water_filter

It is cheap (mine costed about 20$) and low maintenance, just clean it once a month.

I know it exists in several countries, and definitely you will find it in Africa. Hopefully in Mali too.

Good luck

Greg

I would definitely look into 'ceramic filters', chances are they make them locally.  Properly made they can filter out amoebas and bacteria, possibly even viruses.  Plus they are reusable and pretty simple to clean.
They can even be gravity powered (poor dirty water in container on top, clean water comes out the bottom.)


Slow sand filters, etc. will work, but they usually takes a few weeks before biofilter progresses to the point where they start producing clean water.  Plus they are finicky.  You have to continuously flow water through them or the biofilter dies and then it takes weeks to grow back again.

A combination of slow sand filter & solar distillation (SoDis) mentioned previously gives clean safe drinking water for very little cost. SoDis is being taught & strongly encouraged by the World Health Organization.

I currently use both methods but not together. One location has a home made slow sand filter with activated carbon final filter. Removes chlorine & sediment. Water tastes & looks much better. The other location starts with relatively pure spring water in the mountain wilderness. I accept a small amount of sediment there but use SoDis for safety. Giardia & cryptosporidia are not fun. A sand filter will be added soon.

Sawyer Squeeze or mini squeeze. Small. Cheap. Very good filtration. Almost indestructible except by freezing. Thousands of more people would have survived Hurricane Katrina if they had one available. Sawyer snake bite kit is awesome too. Probably not easily available in a remote African village.

I have used all 3 water filtration/purification methods with undrinkable water & all worked well. No intention of fully testing the snake bite kit.  

I'm grateful for my deep potable well, we keep a ceramic candle style gravity filter as a backup. I should probably re-acquaint myself with slow sand filtration it's been a few years since reading of it and don't have practical experience with it. Thanks for posting your question which reminded me of slowsand/biosand filtration.

Appropedia link for Biosand filter (lighter introductory article)
http://www.appropedia.org/Biosand_filter

Appropedia link for slow sand filtration (heavier article)
http://www.appropedia.org/Original:Slow_sand_filtration_water_treatment_plants

Wikipedia link
https://en.wikipedia.org/wiki/Slow_sand_filter

Take a look at this site for a Drinking Water Filtration Kit using 2 each 5 gallon buckets, a spigot, and a water filter embedded with silver to kill all/most of the bugs.
https://www.alloutdoor.com/2013/10/22/monolithic-ceramic-water-water-filtration-system/

This used to be on the Monolithic Dome Institute's (MDI) Web Site but I could no longer find it there.

Either way you might explain the situation in the village your father lives in and possibly get some assistance with setting up something greater than the 5 Gallon system. I know that MDI used to, long ago at least, have a program for such projects.

You might also want to look over the MDI web site for housing as well. Their homes start with what looks like a giant half sphere basket ball. It is a rubberized canvas that has foam blown all around the in side of the shell, rebar hung inside that, and then a quick-crete (light weight concrete misture) blown around the inside of the entire sphere. SO, you end up with a well insulated home that has the insulation on the outside!

Check it out!

Hi! If you are just looking for Drinking and Cooking water, I would get a Big Berkey. The Charcoal filters are amazing! I have used mine for 8 years now, and it has been a blessing.  I was on the road camping, "Out in the Wilds", for 7 of those years.  Having clean water to drink is very important to me.  They have several sizes, depending on how many people are using them, but for me and my little dog, the Big Berkey has been perfect.  :)

Maybe I missed it, but I don't think I saw anything on distillation. Would anybody recommend distilling water in emergencies? Or is that too slow? I have been thinking of getting one, something like the D-Stil: https://waterdistillers.com/products/survival-non-electric-compact-water-distiller-for-emergency-and-survivor-situations

Roy Hinkley wrote:I haven't seen a Berkey gravity filter mentioned. Its the most economical way to have safe water. Period.
Pre filter with something low tech as best you can but using a Berkey or equivalent is  probably the best route to maintain your health.

Love our Berkey but our well water has high turbidity and I would like a viable system of filtration to use in the homestead and even before it gets to my Berkey

Hi Jenny,

As was suggested by Marvin, I would make a prefilter.  I stack four 5 gallon food grade plastic buckets.   All but the top bucket have lids.  The top bucket lined with a pillow case to catch the more heavy debris.  It has a hole in the bottom that drains into the next bucket. That bucket is filled 2/3 with sand.  That bucket drains into the bucket below it that has charcoal. That bucket drains into the bottom bucket that is empty.   All the buckets are connected with short lengths of pipe. The bottom bucket has a spigot.   While this is probably all the filter I need, I then run it through the Berkey. I use this system only when I am using pond water.