In a recent article posted on The Guardian they cover a recent prototype developed at the Cranfield Water Science Institute that provides an odorless nano-membrane toilet that handles both liquid and solid waste through a process called “pervaporation”. This process separates the waste inside the unit via vaporisation through a membrane.
“The vapour is then recovered and drained into a collection vessel so it can be used for irrigation, household washing or even human consumption. The ingenuity of the nano membrane toilet is that it works without water or electricity, two key services lacking for many of those without access to toilets.
Instead of a flush, the toilet uses a scraper mechanism that sends the waste from the toilet bowl into a collection tank below, where the solids collect at the bottom as sediment and where the liquid waste is filtered. The solid waste is removed into a gasifier which converts it into gas and energy.”
It’s a remarkable system with an innovative approach that works off-grid (critical to communities lacking electricity or sewerage), with a small enough footprint that it can fit in a single family home.
Similar to our system – and all current toilet projects honestly – has been the issue of cost for the user and social acceptance. As we’ve mentioned in many posts on this site these two factors can vary significantly depending on where a toilet is being installed. User interfaces can (and often must) change and costs can be negated greatly by moving manufacturing in-country.
On that last point, our very own Myles Elledge is quoted in the piece on our efforts to localize the manufacturing of our system:
“During 2016 we’re working with commercial partners in India to demonstrate [the technology] and hopefully progress towards manufacturing in-country,” says Myles Elledge, a senior director at RTI. “We are targeting [a cost] of about $2,500 per unit, which would serve about 50 users per day and would get us to the Gates Foundation target of five cents per person per day over a 10-year life.”
It’s a great piece that further extends on the amazing innovations in sanitation that are being created these days, as well the corresponding challenges that exist trying to get this technology to the people that need it.