Earlier this year, we saw Bill Gates drinking water that was originally taken from poop. The poop machine that turned dirty water to clean water is also called the Omniprocessor, designed by Peter Jackini and partially funded by the Bill & Melinda Gates Foundation. Gates wrote on his blog that he was impressed with what Jackini has built and he is thrilled with the business model.

The machine was installed in Dakar, Senegal, a Western African city of which one-third of the 3.4 million people does not have access to potable water. Residents of the place have to manually remove the waste from pits or septic tank for sanitation, which can increase the chances of contamination and harbour disease in the community.

The Omniprocessor is the first of a larger project that aims to save lives and turn waste into something useful. The use of the machine can also reduce disease in countries that do not have a sustainable source of drinking water.

The Omniprocessor can produce clean water, electricity and a little ash from human feces. It appears like a tiny chemical plant. One conveyor belt of the machine feeds poop in one end, dries it, purifies the water and finally burns the solid residue for its energy consumption. In a word, the machine powers itself by generating electricity in the process and by burning the solid residue.

The machine costs between $1.5 and $2 million, but Jackini maintains that the machine owner will experience profits and returns in just a few years because there is money to collect at each step of the way. The machine will get money for first, taking away sewage and next, for selling electricity and water.

The Omniprocessor tested and run in Dakar is said to be capable of treating one-third of Dakar's sewage. The machine makes sanitation in Dakar cheaper since runs on the electricity and fuel it produces and the generated water can be used for irrigation or for drinking.

Gates said that the test run of the machine in Dakar is successful and that he plans to bring Omniprocessors to other places with poor sanitation.