This video shows RTI International’s Gates Foundation funded toilet running a full-loop on the solid processing side for one of the first times.
The cycle, shown below in the diagram, processes human feces into a burnable material using the heat created by burning an earlier processed batch of feces. Motors, actuators, a whole lot of stainless steel (amongst other materials), Programmable Logic Control and LabVIEW, along with a lot of clever engineering and skilled fabrication have brought the system to a point where the concept has now been more than proven!
Next we move forward with reengineering and improving to reduce thermal losses, reuse extra thermal energy to start powering portions of the system, and trying to achieve a better mass balance in which we are able to dry feces at the same rate that we are able to burn it.
The last week of December saw a major milestone, as our first batch of feces was dried solely by the combustion of previously-dried feces on the current Beta system set-up in our lab at RTI!
Our feces combustor, engineered by our partners at Colorado State University, is shown running semi-automated; National Instruments’ LabVIEW controls the pressure differential through the system and displays/records temperature data as “fuel” (dried human feces) is manually metered into the combustion chamber using two ball valves as an air-lock.
The heat from combustion is used to dry the human feces applied to the cast-iron automated rotating plate inside the dryer apparatus.
Next, we begin working toward a fully-automated, fully-closed loop in which feces is dried, scraped and ground, then metered into the combustion chamber for burning.
Thanks to our ongoing field testing efforts, we’ve naturally discovered ways that we can improve our existing prototype. These new modifications better serve the people that use our toilet as well make it function more effectively.
To date, we haven’t shared details on the changes we’ve worked towards, but today we thought we’d share some pictures of our most recent alpha prototype that is now being built by L&T in Vadodara. We are currently aiming for a completed installation in April 2015.
Below you’ll find pictures of the outside of our prototype, as well as isometric views of it’s assembly and the features we’ve added/improved upon.
All of these pictures can also be downloaded as a PDF here.