It's like the carbon in a water filter it gets rid of a lot of things you don't want to consume. The em or bokashi part is really interesting Cuauhtemoc has cleaned quite a few water courses with it I think in this video he mentions some of these bacteria are needed for fish like salmon.

https://m.youtube.com/watch?v=v_0LU0c7aaQ&pp=ygUQY3VhdWh0ZW1vYyB2aWxsYQ%3D%3D