Hi Hoa ! You're right, this project can also suit to people who don't have place or soil around to make gardening. They can put them on the rooftop, inside or on hard surfaces. It's an alternative soil solution for hard conditions (desert, urban, too cold or too hot outside, ...).
Hi Lauren ! Like I said, to create filters from grind, the only useful wastes are the foams due to their porosity. I need two levels of filtration, 10 and 50 microns, to clean the water and keep the particles. So the grind will be pressed, in a mould, to a different level to obtain two specific density, and thus porosity. Water pressure will do the rest. Like carbon filter, the first filtrations have be thrown out before a fully functional use.