Green Prophet’s article “Daring Moroccan university recycles urine as drinking water” concerns taking a closed-loop water cleansing system developed by the European Space Agency (ESA) for use in space and using it here on earth in areas where clean water is scarce. The article describes the process:
Powered by both solar and wind energy, the closed-loop water cleansing process involves controlling “… organic and ceramic membranes with holes just one ten-thousandth of a millimetre across – 700 times thinner than a strand of human hair,” according to Phys.org.
“These tiny pores can filter out unwanted compounds in water, in particular nitrate.”
It later comments that
This is all pretty heady stuff for the Middle East, where recycling waste water has long been viewed as risky business given the strong view that Muslims have about all things potentially unhygienic. There are complex rituals associated with anyone who defiles themselves in certain ways – by having sex, for example, or coming into contact with impurities.
But desperate measures are required during desperate times; we think this experiment could have enormous ramifications not just in Morocco, but throughout the region. It’s important for local people to notice science’s efficacy so that they can trust the source of their drinking water.
It is also important for people writing about these things to dig deeper into the issues that are related to Islamic legal scholarship. Of primary concern here is whether the recycled water is filthy, pure, or pure and purifying. And if the water is not pure and purifying (i.e., that it is not only suitable for drinking but also for making ablution) , what would be required to produce water that is pure and purifying? As a first approximation from the Shāfiʿī school: it should be enough to remove the impurities to the extent that the waste water characteristics return to the original characteristics of pure water – provided that that this water is then combined with at least 212 liters [qullatayn] of pure water. Chemicals added to the water may be an issue depending on the quantity added, and whether they were added for the sake of the water or the water system.
Other schools may be more lax or more strict. (From what I recall, in place of the Shāfiʿīs’ 212 liters, the Ḥanafīs require a body of water large body of water large enough that a disturbance on once side of the water will not change the calmness of water at the other side. I wonder how that would work in 0G situations.)
Another major concern is whether the water cleansing system’s efficiency. Is it only enough for drinking water? Or is it enough to allow its users to use the water for ritual purposes? In times of necessity or scarcity, many religious rituals do allow for alternatives.
There’s more to this than trusting and taking notice of “science’s efficacy.” It’s also important for scientists and policy makers to work with scholars of Islamic law to seek viable harmonious solutions and policies.
Readers may also be interested in “Why is water so important for islamic rituals?”.
UPDATE – Some sizable Muslim populations already depend on recycled water. Take Singapore, for example. I shy away from answers that rely on dire necessity and need. We already have enough instances of natural and man-made necessities that could have been avoided. We really ought to do our upmost to not make any more. That is one reason why I think that we should not stop where it becomes technologically of politically inconvenient and, thus, fail to explore options that would allow us to avoid relying upon necessity and need. Additionally, if we did invoke them, then what does that say about us for creating or acknowledging the condition and then doing nothing about when we could have?
Water recycling is important. Getting water from somewhere else is not always an option, and if current water security concerns are left unchecked that will become increasingly the case.