"For the solid waste, which also can include toilet paper, we are mixing it with our chemical formula for not more than 30 seconds, and it will turn immediately into odorless, sterile fertilizer," Halperin said. "The fertilizer will be automatically dropped into a removable canister, where it can be collected from time to time and then be used for field and/or home crops."
The liquid waste will be sterilized separately in another reservoir, and then pumped up to flush the toilet, all powered by heat energy created from the solid-waste process and stored in a battery. According to the still-secret drawings of the patent-pending device, the internally created heat would even power a light inside the stall.
"Just to back up the energy source, we will also use a small solar panel on the roof," said Halperin. "There's no need for any sewerage or electricity infrastructures or connections. No need for water to flush. No special maintenance - the chemicals can be put in its dispenser once a month, and the cost of one use is only a few cents."
These features are a good fit for the Bill & Melinda Gates Foundation's "Reinvent the Toilet Challenge," which aims to improve on the limitations of the 18th-century toilet still in use today, for 2.6 billion people lacking access to sanitation.
According to the foundation, reinventing the toilet for use in developing countries could save millions of lives and help end poverty. About 80 percent of human waste goes into rivers and streams untreated, and 1.1 billion people don't use a toilet.
The winning solution must be hygienic and sustainable, with an operational cost of no more than five cents per user per day. It may not discharge pollutants and must generate energy and recover salt, water and other nutrients. It may not rely on water to flush waste or a septic system to process and store waste.
The one-year Gates grant is first-phase funding. If the foundation likes what it sees, Paulee CleanTec will then submit a second proposal for a $1 million or $1.5 million grant to complete development and build a prototype.