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.
One of the core responsibilities of RTI’s system, now under development, is to separate liquid waste from solid waste. Once separated, the solid waste is then convectively dried and delivered to a combustion system. The waste heat from the combustion system is converted to electricity using thermoelectric modules which, in turn, power the entire toilet.
We are happy to announce the that our alpha system, currently housed on CEPT campus in Ahmedabad, has produced real dried poop pellets and successfully completed a full burn, incinerating them!
This is quite the milestone for our project and we couldn’t be happier for reaching it!