A Free Minimalist Urine-diverting Dry Toilet (UDDT) for the Unhoused, Poor or Disaster-stricken

- Two 4-liter plastic bottles, like those used to sell bleach.
- 50 centimeters of tape.
- 2 meters of string.
- Four sticks, 25 centimeters long (or a box the right size).
- Some normal, woven, polypropylene sacks, like those used to sell 100 pounds of flour, rice, or whatever. Biodegradable, jute bags (like coffee sacks) can also be used and even have an advantage (see #7, below).
- A small sheet of plastic.
Instructions
(1) Make a portable, ecological urinal from the two bottles, cutting one diagonally (as shown) and joining them together mouth-to-mouth with tape and then firmly with string. This is a very useful item, even if one has a more up-scale outhouse, as it can be used for peeing next to bed in the middle of the night, without having to go out into the dark among snakes, insects, rapists or other creatures. It can also be used during the day wherever there is enough privacy.





Discussion
“Conventional wisdom” or fecophobia (the irrational fear of feces) may lead people to have the following doubts about this system:Couldn’t the fecal pathogens get out through the woven cloth of the sack?
Aside from hookworm larvae, fecal pathogens do not actively move anywhere and just wait passively to get washed into someone’s drinking water, brushed onto someone’s unwashed hands before they eat, or carried by flies to someone else’s food. These are the risks of open defecation, with fecal pathogens set loose in the environment. Liquids do not flow out of these sacks, given the dry cover material we add after each use, the separation of the urine, and the protection against the rain. The permeability of the woven cloth is actually a positive thing, since this allows humidity to evaporate out and oxygen to filter in (without smell or flies coming or going), so the feces can decompose normally, with the pathogens dying off at an exponential rate. See an example of letting feces decompose in these woven sacks in this video.
As shown in this graph from the Humanure Handbook by Joseph Jenkins, Fecal coliform bacteria die in the soil at an exponential rate.
Can we be absolutely sure that all the pathogens will die and that no one could possibly ever get sick via this system?
No. Someone could come along and open the sack before it is time, without reading the tag, but any system can go wrong if not used right. What we can be sure about is that all the fecal pathogens are still alive and kicking in people’s fresh feces that might otherwise go straight into the environment. We also know that these pathogens die off at an exponential rate as feces decompose. The important thing is to keep these nasties jailed up while this is happening and every day of containment is a victory in the war against disease. Essentially all of these pathogens are anaerobes adapted to live in the absence of oxygen, in the aqueous habitat inside our guts, and there is only a certain amount of time they can hang on in a dry, oxygenated substrate before infecting the next person. Given this situation, the most persistent fecal pathogens have evolved desiccation-resistant packaging, like the amoebic cyst and the shell of the Ascaris egg, but even these can only protect them for a certain amount of time.
A key factor is the rambunctious and relentless nature of the microbes in rich organic soil, eating everything that does not eat them first. Most pathogenic microbes would be easy prey to soil organisms and it has been shown that fecal bacteria die-off faster in species-rich soil, as I recommend using here, optimally with the reuse of finished compost as cover material, with exactly the microbes that broke down the feces of the previous cycle, and which are not human pathogens.
Schönning and Stenström (2004) recommend storing the feces, with an ample amount of wood ash or mineral lime for over 2 years in the Temperate Zone and 1 year in the Tropics. Personally, I think this is overcautious, especially in the biodiverse, warm Tropics, but these detention times can easily be applied if there is enough space and it makes people feel more comfortable. These times refer to the most persistent fecal pathogens, which are the eggs of the Ascaris Giant Roundworm, and all the really dangerous microbial pathogens are wiped out in less than three months. We have done trials to look for Ascaris eggs in our fecal compost, here in Amazonian Ecuador, and have yet to find any beyond four months of decomposition. More trials need to be done and a simpler, more conclusive protocol that mostly only requires a microscope needs to be developed. And even I store the feces for over a year, for more peace of mind of all the users.
No one wants to go on record recommending a detention time that may potentially allow someone to get sick, and this is especially the case with governmental and international organizations. I am nonetheless willing to go out on this limb, given that the worst alternative is to continue with the currently abundant cases of open defecation, raw sewage going straight into so many rivers and bays, and 2.6 billion people in the world that do not have any sort of decent toilet. And, if over time, we find that we should modify these suggested detention times (longer or shorter), we can do so.
Aren’t we supposed to store urine for a number of months to sanitize it before applying it on the soil? This concern is due to the possibility that feces may have contaminated the urine through people using the UDDTs improperly or having accidents … and this is very unlikely with this “bare bones UDDT”, in which the user holds the urinal right where it needs to be. If an accident were to happen, the user could dump the urine in a hole in the ground and cover it up, instead of spreading it on the surface of the soil. In places where there is the Bilharzia parasite, Schistosoma haematobium, urine should be spread on the soil far from lakes and rivers, so that this parasite cannot get to the freshwater snails it needs to infect in order to continue its life cycle. Won’t some animal, like a dog or a rat, tear open the sack and spread this dangerous material around? Experience has shown that they do not, especially if we are using soil as a cover material, in particular that special recycled soil. There have been a couple of cases of mischievous dogs, but only when pure sawdust was being used as the cover material. Soil and finished compost are also among the best filters for odors. Fecophobia aside, other important questions can arise: Why should we protect the sacks from the sun? Wouldn’t the solar rays help to kill the pathogens?
A graph showing the time necessary for various human fecal pathogens to die at different temperatures, from Feachem, R.G., Bradley, D.J., Garelick, H. and Mara, D.D. 1983. Sanitation and Disease – Health aspects of excreta and waste water management. John Wiley and Sons, Chichester, UK (as cited in Schönning and Stenström 2004). For example, all pathogens die within one hour at 65° C, or within a month at 45° C.

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