Coming to a bathroom near you.
On their own, poop and pee can be very useful; urine is full of phosphorus, and poop is an excellent source of nitrogen. A lot of fossil fuels could be left in the ground if they were not being turned into fertilizers. Poop is also a lot less smelly and composts much more quickly if it is not mixed with pee. That's why we have long been fans of urine-separating toilets. As one Swedish researcher noted, "Don't mix what God separates."
We have shown a few in the past that have been problematic, but this new design from the Swiss Federal Institute of Aquatic Science and Technology (Eawag), Austrian design studio EOOS (the team behind the brilliant Blue Diversion Toilet), and plumbing manufacturer Laufen is different; it addresses many of the earlier problems.
Perhaps the main difference is that it doesn't look different; it looks like a regular toilet. Complaints about previous designs included that they looked weird. "Today’s loo offers an out-of-sight, out-of-mind experience." This works differently:
The product’s key innovation is a “Urine Trap” invented by EOOS Design, which directs urine towards a concealed outlet using only surface tension. Laufen applied this concept to a new toilet design featuring a ceramic bowl that is optimally shaped to guide the water flow. The interface’s easy maintenance, low-tech, hidden innovation ensures it is indistinguishable from any other high-end WC. Save! represents a new format for a familiar product that is business ready and could play a key role in the future of wastewater management.
Laufen says, "No change in user behaviour is required; however, men have to urinate while sitting." That's quite a change in male user behaviour, which is why there should probably be a urinal as well. It will not work for everyone, everywhere, as makers of the earlier No-Mix toilet found:
Women, for their part, are reluctant to sit on public toilets for hygiene-related reasons. Some users find it difficult to adopt the required sitting position. Children in particular have problems targeting the right compartment, which increases the need for cleaning.
But it does seem to be a dramatic improvement, one that anyone would be happy to have in their home, and they seem to have really figured out what to do with the output:
The collected urine is then processed using "microbial transformation, activated carbon filtration and distillation to transform source-separated urine into a fertiliser called Aurin which has been officially licensed by the Swiss Federal Office for Agriculture for use on all plants." Keeping urine out of the waste stream also removes a major source of excessive nutrient load (eutrophication) in ecosystems.
That's key: "biosolids" can be extracted from the waste stream and turned into nitrate-rich fertilizer, either at a sewage treatment plant or in a local liquid/solid separator, but the phosphates in the urine have always been lost and released into the environment.
I have often tried to make the case that we should all have composting toilets in our homes, to stop all this stuff from getting into our lakes and rivers. People have often said I was nuts. Perhaps this is a better idea for new developments where they can put in the separate plumbing.