Tuesday, March 10, 2015

A Step in the Right Direction?

  I'm back here in the indigenous homeland of the Ngäbe people of Panama working with rural villages to improve their access to clean water, but I've also been thinking a lot about a problem every bit as troubling as contaminated drinking water--the transmission of disease by dirty hands. Diseases such as diarrhea and pneumonia are the top two killers of children under five world wide, but these deaths are largely preventable. The most effective proven intervention?  Hand washing with soap. 

  We  know we should wash our hands of course and we take hand washing for granted. For us it's just a matter of remembering to do it. Sinks with soap and running water are always around. But that's not the case in the developing world. Often a family's household water supply is carried to the house in buckets and everyone dips into those same buckets with whatever kind of cup is handy for all their water uses: drinking, cooking, dish cleaning, and if it should happen, hand washing. But would you even want to encourage people to scoop water out of there to wash their hands? Could they possibly do it without contaminating the rest of the water?
  It's easy enough to lecture people about how they need to be washing their hands, but that doesn't help them with how they could effectively wash their hands. In places where there aren't sinks and running water anywhere around, that's no small problem.
One charmingly simple and potentially effective solution is the tippy-tap. Here's a basic model.
  It's quick, cheap to set up, and it provides a hands-free, steady trickle of clean water just by stepping on the foot pedal. I like the super-efficient use of water and the hygienic hands-free operation--features we have now incorporated into our own first world, high-tech sanitation solutions--just wave your hands under the faucet and a nice portion of water comes out.
  A tippy-tap makes a fun demonstration when you're teaching the importance of hand washing, and if you do an image search for tippy-tap on the internet you'll see dozens of pictures of just that sort of activity in places all over the developing world, much like this one we held at our school.
  The problem with the tippy-tap is that it all too often doesn't go any further than that--a neat demonstration that no one actually adopts and keeps using. There are plenty of behavior change theories that come into play in that failure, but one big obstacle with the tippy-tap is the frequent maintenance, i.e., taking it down and refilling the jug with water.
  A tippy tap can work perfectly well in a best case scenario, like a motivated peace corps volunteer. I used this one as my kitchen faucet for three years and was completely happy with it despite the need for regular refills. But if we're going to promote an “appropriate technology” that will actually be adopted we have to be realistic about both its durability and how much effort people will go to in order to use it, especially when it is addressing a need that they may not feel that acutely, like the need to wash your hands.
  I've been thinking about this challenge since I began my training as a water and sanitation volunteer here in Panama. We learned about the profound health impact hand washing can have, and we developed educational charlas on the subject to share with rural villagers, but when it came to the practicalities of it all I didn't seem to have that much to offer. This failing seems especially sharp in the context of latrine projects that don't include a workable hand washing facility.
  With all of that in mind, I'm cautiously enthusiastic about something new that we're trying out with our latrines here. It's a hands-free sink that utilizes the rainwater collected from the latrine roof. 

 We built these small ferrocement rainwater tanks to provide water for the bidets that I've described in some earlier posts. They're working fine, but washing your hands over the bidet at the end of a visit to the latrine is an awkward and less than sanitary process of passing the hose from hand to hand and really isn't satisfactory. The low roof of the latrine means the rainwater tank is too low to have a gravity flow faucet at normal sink height, so the solution here is a little foot pump that can be cheaply and easily put together in the campo with just a little bit of fairly easy to come by hardware from town.
  The bladder for the pump is just a short piece of old motor cycle inner tube that is hose-clamped over a 2” by 1/2” PVC reduction fitting. The free end of the inner tube gets doubled over and nailed down tightly under a strip of flattened PVC pipe.  
  The system works to pump water up to the faucet by virtue of two homemade check valves. Here's a sketch:

  The first check valve is in the 1/2” line flowing down from the tank. Water flows by gravity down into the bladder but when you step on the bladder the check valve closes and won't let water flow back towards the tank. That leaves the water with nowhere to go but up through the second check valve in the vertical outlet tube until it reaches the top of the pipe, spills over and flows down and out of the faucet. The second check valve is in that vertical tube and it keeps the water that you're pumping up from falling back down into the bladder when you lift your foot. The result is a nice flow of a few ounces of water each time you step down on the bladder, with the bladder refilling from the tank when you lift your foot.

  You might find factory made check valves at an unusually well-stocked hardware store, but that would triple the cost of the whole setup, and it's not that hard to make your own with just two 3/4” by 1/2” pvc reductions. 
  You make the valve body by thermoforming an extra long bell on the end of a piece of 3/4” pvc pipe. Cut off about an inch and a half length of that bell and that's the valve body. With a hacksaw, cut a little section out of one of the reductions as shown in the photo above. Glue that reduction into one end of the valve body.
  Trace a circle the size of the end of the second reduction onto a scrap of inner tube and cut it out with a pair of scissors. Trim it until it just fits inside the valve body and slip it into place so it sits on top of the first reduction.
 Now add some just a little glue to sides of the second reduction and slide it into the valve body, pushing it in tightly in order to sandwich the little disc of rubber tightly between the two reductions. The open section that you cut out of the first reduction will let the disc bend up, opening the valve so water can pass through, but the reverse flow will push the disc tightly against the second, unmodified reduction keeping water from flowing back in the other direction..
  You can test the valve by blowing on it to make sure air only passes in one direction. (That also makes a fun balloon inflating toy for the kids!) Mark the valve with an arrow to indicate the flow direction and you're ready to go. The first pair of these check valves have been in service for six months now and are working fine with the low water pressure involved in this pump.

  We made the sink itself with basic front-porch ferrocement techniques starting with a mud form to create the shape of the bowl.
   A little bit of quarter inch reinforcing bar gives it some strength along with some tie wire or chicken wire stretched along the bowl.
 Plaster the bowl with two thin layers of sand-cement mortar (2 : 1 mix).
  For the drain, make some radial cuts in the end of scrap of pipe, heat and flare out the little ears to embed the pipe in the bottom of the bowl.
 The exact design of the sink will depend on how you can figure out to mount it on the wall. In the latrine pictured above I ended up molding a flattened piece of pvc pipe to make a kind of gusset that holds the sink against the wall.

 I mentioned being cautiously enthusiastic about this little hand washing sink because I know there are plenty of reasons why seemingly good ideas and well-intentioned initiatives end up fizzling out, I've seen a lot of that around here. But I don't have to look far to see plenty of reasons to keep trying to take some small steps in the right direction.

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