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The Nano Membrane Toilet (cranfield.ac.uk)
41 points by ph0rque on Jan 13, 2016 | hide | past | web | favorite | 40 comments

Is residential water usage really a large problem? I assume that municipalities have a decent ability to reclaim and reuse much of the water flushed down the drain and toilet.

I know at least for California residential water use makes up just 15%[0]. I know every little bit helps, but a toilet is an incredibly simple invention and it would be a shame to replace it with something so much more complicated.

[0] http://www.environment.ucla.edu/media/images/water-fig1-lrg....

I wish you would read the article and watch the video. The target market and business model is well explained. Can you imagine a region in the world that does not have running water and sewers and may actually enter in the "first world" before those services do? Well then, that's what this toilet is for.

Composting toilets don't need water either.


Alternatively, just try to divert urine so it never mixes in the first place:


Both of these seem on first glance to be easier to maintain.

Yeah, this toilet isn't for rural use. It is for places that should have sewers but don't and that probably never will get sewers. It is for dirty cities in the third world.

Will the cost of these toilets ever make sense for that?

When I see things like "Turn a 2L bottle into a light" for a really poor area - I think awesome, something they already have laying around can make their lives way better.

When I see things like "Nano-polmer super toilet for those without running water" I just kind of shrug. Seems to cost more than adding running water, while still not providing a clean place to drink.

What am I missing?

(I think!!!) it is a problem of scale.

In 3rd world locations, you can be walking 3km every 2nd day to fill a jerrycan of water.

If that's the case then you aren't going to use that to flush.

And even if you do (using grey water after cleaning etc.), then you won't have the toilet inside the house.

So how much does installing this super toilet cost, best case?

How much to run a line of fresh water to the house?

If <cost of toilet> is not less than <cost of fresh water line / 10>, it seems like not a win - as fresh water can solve both drinking and help with sanitation (though not get you all the way there).

California has water that is next to free from the snowpacks. Water is so cheap that desalinated water, which costs about $0.45/1000 liters, is almost never seriously considered a major source of water (as compared to places like Dubai, or even Singapore, where it is a major source of water) - even given that vast portions of the population live right beside the ocean.

Several iterations of this device might result in something very useful in areas far away from the ocean (which makes desalination difference), and lacking the major infrastructure for centralized water recycling.

There are areas in the world that don't have the necessary infrastructure for traditional toilets. Given the funding by the Bill and Melinda Gates Foundation the goal is probably deployment in those areas.

The idea with a waterless toilet is that it can be cheaper than installing a conventional toilet and plumbing. There are hundreds of millions of people that do not have plumbing.

And yet this problem has already been solved with composting toilets for many years.

Why do we need to build such a fancy and complicated device when all you need is to pee in a separate bucket from your poo, and let the poo aerate/dry naturally? Mix in some dry mulch and you're done!

Urine itself is sterile and can be easily treated/recycled.

Composting toilets have problems. This is effectively a composting toilet that solves all those problems. The biggest problem of all is that there is just not enough time and storage to compost on site (on site being your bathroom). This solves that problem. If you are going to take the poo out of the bathroom at all for composting elsewhere, then you might as well just take it all the way out of the house and to a facility. If you are going to take the poo out of the bathroom at all then it really needs to be tidy. This solves that nicely.

>Urine itself is sterile

This is a misconception that particularly annoys me, probably because it was the (incorrect) excuse a nurse once gave me when he accidentally spilled a urinal filled with liquid all over me while I was bed-ridden in an ICU. [0] [1]

[0]: http://www.smithsonianmag.com/smart-news/turns-out-urine-isn...

[1]: http://www.stritch.luc.edu/newswire/news/study-debunks-commo...

    he accidentally spilled a urinal filled with liquid all over me while I was bed-ridden in an ICU. [0] [1]
Well that's a horrible experience. I too am quite surprised the sterile urine legend lives on.

Agreed. We have a composting toilet at a remote cabin, and it works great. No muss, no fuss, no odors, just rotate the bins a few times a year and dump the dried mulch.

Now imagine eight people using that toilet every day all year long. Imagine that household is in a city of 200,000. All that poo is never going to compost fast enough. This new type of toilet is for high usage and high adoption rates. It could turn a total cesspool of a city into something clean. A composting toilet in every home in the same scenario would just result in mountains of barely degraded poo at the end of every street.

But the toilet discussed here also has solids that need to be collected and disposed of. Composting toilets come in varying sizes, and properly maintained, result in mulch as the end product, not mountains of barely degraded poo.


My late father recently developed a waterless toilet which is significantly simpler and likely cheaper than this one.


Neat. Reminds me of the nappy bins.

However, the one in the video seems more geared at sustainability and reuse. They filter the water out of the pee. Dry out the poo for fertilisation.

That schematic view of human feces is....let's just say it's incredibly optimistic.

"We assumed spherical turds to make the maths easier for engineering the prototype."

Then again living in the USA has accustomed me to commercials which represent female menses with water, dyed light blue.

Agreed. The whole concept is too complicated for the real world, in my opinion. But, if the team is willing to iterate based on feedback, and incorporate some of the advances of other composting and incinerating toilets, the end product might work really well.

That is exactly what i was thinking - making this produce compost instead of waste intended for a collection facility would be not only more useful in developing areas, but could even improve the urban gardening/homesteading movement. and lets face it - in developed nations, it is us crazy hippie folk who would buy this anyway.

In developing areas, people grow food as close to their drinking water as possible to make watering and/or irrigation easy. I don't know if anyone wants to recommend that they start adding human waste to the mix.

I'd love to know where you are talking about, because everyone I talk to does exactly the opposite. We know we are going to use animal waste, and other compost, to fertilize our garden beds. So we pull our drinking water from upstream of any food production. my family does not use humanure in our systems, but it certainly is done by other people and in other areas.

If there really are developing areas who fail in this design principle, they need education on how to design their food production. Holding back a useful tool just because some people might use it incorrectly doesn't make sense. But most people who are even somewhat self-sufficient know that the flow of water is a crucial design point.

If not composted and used productively, then human waste is just a pollutant. But if you can increase food production and have a productive recycling of materials at the same time, you are killing two birds with one stone.

I find it so effin poetic. Everything is simply separated and ""ready"" for reuse. I wish people could see it that way too.

I often wonder about the cost of toilets on large scale.

They didn't show previous scene of the rabbit on the toilet.

The problem is that the toilet's estimated cost is $0.05 per user. So for a 4 person family potentially living on only a couple dollars per day this would make up 10-20% of their living expenses. This isn't like our budgets where we can afford 10-20% because we are WAY past trying to eat and live. This is 10-20% of all the money you have for food, clothing, and medicine.

Also, I'm assuming the toilet will go up in price as more people try to make more off the system.

All that said, I welcome the Nano Membrane toilet to the much needed market. I'm all for composting toilet technology as our current system of simply creating raw sewage then trying to treat it with massive amounts of chemicals (which are very bad for the environment) isn't sustainable.

1) Natureshead, 2) Airhead, and 3) Separett toilet

These three all much better suited to low cost, rural uses. For more hi-tech versions we have Sun-Mar. However, all these still cost at least $1,000 USD.

It might be a good target for a municipal service. Effectively an overland sewer that gets to use existing infrastructure (the roads).

For "low cost, rural use" - nothing beats a hole in the ground. :-)

Digging a safe latrine pit is more complex than you might think!


Plus they have a limited lifetime; they fill up, and you need to dig a new one.

"low cost, rural use" are two phrases that don't appear in the article. This is for relatively affluent people (living on $5 a day not $1) in cities in the third world.

It would also make sense in developed countries: shitting in water makes it much more complicated to treat afterwards, and greatly increases the ecological footprint of that processing. Moreover, it makes failures to properly treat much more dangerous (human feces are where you most easily find pathogens specialised in human invasion, besides human cadavers).

Feces compost just fine in a dry environment, if you mix it with enough carbon (dried plants or sawdust). No treatment, except letting it decompose over a couple of years, and very little smell if the nitrate/carbon/humidity balance is respected.

Of course, water companies wouldn't be thrilled by such a simplification, and people like the illusion that their poo-poo just magically disappears when they press a button.

Even simpler mechanisms clog and I don't think this scraper can do such a good job, but this still could be better than a septic tank or others alternatives.

This device has quite a bit of moving parts, needs periodic part replacement, and requires electricity to operate.

What does it do with the toilet paper...

that's just more fiber. Besides, in many of the countries targeted by this, people wash with water, rather than sweeping with paper.

It is designed for no running water, so I would assume no bidet water also. Could go for the shared sponge ala Rome (was that really healthy?)

Can someone create a social enterprise that uses this idea to generate profit and make a wider impact?


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