https://finance.yahoo.com/news/bill-gates-aims-save-233-020000607.html

Holding a beaker of human excreta that, Gates said, contained as many as 200 trillion rotavirus cells, 20 billion Shigella bacteria, and 100,000 parasitic worm eggs, the Microsoft Corp. co-founder explained to a 400-strong crowd that new approaches for sterilizing human waste may help end almost 500,000 infant deaths and save $233 billion annually in costs linked to diarrhea, cholera and other diseases caused by poor water, sanitation and hygiene.

One approach from the California Institute of Technology that Gates said he finds “super interesting” integrates an electrochemical reactor to break down water and human waste into fertilizer and hydrogen, which can be stored in hydrogen fuel cells as energy.