Posted by Matt on Tuesday, March 22, 2011
UPDATE January 2013: I am conducting an evaluation of the project hopefully to be completed in late February or early March. Will update then.
Or I guess the question is what are dry bathrooms. Dry bathrooms are known by many names, and I tend to interchange them a bunch. Dry bathrooms aka eco baños, ecological bathrooms, compost bathrooms, compost toilets, etc. are designed in the most basic sense to be part of a process to turn human waste into fertilizer.
Wait!! But didn’t you say shitting in the fields was part of the sanitation problem in the first place?
Well, I never did say it but you’re right, Jimmy (errr…Timmy). Directly shitting on plants is bad. Real bad. The use of night soil (a cleaned up phrase for the combo of shit and piss) directly on plants is a point of high risk in the diarrheal circle. Viruses, worms, and germs find new homes in plants, which if not carefully washed, are ingested by humans causing a host of new problems.
Alright, Lyle Lanley. What’s this dry bathroom thing then?
Depending on the model, shit and piss are handled separately from the beginning to end stages. The most basic design is a box with a toilet seat, and then a bucket inside for the shit/piss mix. After every use, add in saw dust or something to start absorbing the urine. Once full, you just add the bucket to the compost pile and let it sit and mix in for at least six months. During that time, all the bad things in our poop such as viruses and worm eggs die as the temperature of the compost pile is higher than that of the human body. In fact, most of the bad stuff dies off within a few days…just the pesky eggs stick around.
So that’s what you’re doing?
Yes and no. Families here don’t readily practice composting as most of their food scraps are fed to the animals, and there’s not too much organic matter left. The models we’re implementing are slightly more complex, but not complicated. We’re building a unit 2m wide by 1.9m long by 1m tall out of a concrete floor, bricks, and then another concrete slab to top it all off. The inside faces of the bricks are sealed with a mix of mortar and SIKA. The top concrete slab has a hole where we put the special toilet seat. This seat is pretty simple: you sit, and the poop falls through the back half, while the urine is separated in the front half and channeled outside the unit. The urine is either collected in a bucket, or goes straight into a gravel pit. After six months, the family moves the toilet to the other side of the unit and uses that fresh side while the poop decomposes in the other. When the second chamber is full, we’re ready to take out the first mix and throw it in the air and let it fall like snowflakes…or use it as fertilizer. The unit, in this case, is surrounded by adobe blocks and the front has a elevated base floor to make it easy to sit on the unit. I tell you, I’ve sold these things in Brockway, Ogdenville, and North Haverbrook and by golly it put them on the map!
Yep, that’s why you add 3-4 parts water to dilute it. Add in some spicy peppers and you got a handy organic insecticide, buddy.
Quick: Used the bathroom but I got toilet paper. What to do, what to do?
Well, if you wanted to go extreme, you could use leaves and just throw it in the mix. But also, the toilet paper will decompose, so it’s safe to just throw in with the poop.
So you’re just going to build these things one time over and be done?
Negative. One of the annoying things about dry bathrooms is training the families on use and maintenance. It’s just not a one-time thing. Once built and in use, visits need to be made to make sure the bathrooms are in (proper) use, and there’s nothing wrong with the unit such as smells or flies. And it’s helpful at the six month mark to remind the families to switch over.
Is there a chance the track could bend?
You’re in the wrong meeting, my hindu friend.
Why not just build regular latrines?
While regular latrines are a solid solution, often times the pit fills up and no one does anything so the latrine goes out of use. Or, as latrines are usually cheaply made, the smell and poor maintenance are usually enough to discourage use. Latrines also need to be built a certain distance away from the house as well as water sources. In fact, the ground level in one of my communities is so high (how high is it?) you can’t dig a hole deeper than a meter without hitting water, making latrines a contaminant (well, for those living downstream).
Why not a septic tank?
Beyond cost, a septic tank takes a lot more time and effort. It also requires more water, which many of these communities don’t have much of to spare. Besides, if the septic tank or one of the lines backs up, usually no one nearby has any idea what to do, creating a public health issue. No geological survey required, as dry bathrooms can be built almost anywhere.
Try this on for size: where don’t dry bathrooms work?
Dry bathrooms are best suited for rural agricultural communities where water resources are scarce. Furthermore, people there own their own land or will be able to sell their fertilizer. Many times, people will work in agriculture, but it’s someone else’s land and the workers can’t just throw on whatever they want. Lastly, it’s easier in a community that does not have access to drainage systems. It’s hard to convince families of the benefits of dry bathrooms when their neighbor has indoor plumbing.
Where can I find more information about this exciting topic?
Your local library! Or, check out the ‘Humanure Handbook’, as well as ‘Sanitario Ecologico Seco’ by Lourdes Castillo Castillo (in Spanish). I hear this Google thing is taking off (as long as you don’t click on the eHow or about.com links). As well, feel free to contact me directly (matthewDOTwilliamDOTfuller A T G MAIL DO T COM).