> Bio waste is best waste there is because what we need is whatever material we extract from the fields to go back there to fertilise it. Anything that we extract from the soil that isn't going back there is essentially eroding it.
But if that waste was going to a landfill instead of "the fields", then isn't it better if it gets put to a productive use rather than an unproductive one?
If you can somehow collect coffee grounds to make cement, you can also collect is as part of generic biological waste fraction and use it as a fertiliser.
I happen to use coffee grounds (yes, we make a lot of espresso at home) and we already use spent coffee grounds as natural fertiliser. It improves the soil for some of the plants, improves aeration, attracts earthworms.
Getting the thousands of independent cafes to donate the grinds and have a way to collect them is going to be a challenge either way. Maybe the concrete option adds enough $ value to make it worth someone to go around and collect them.
No, not if the cost to extract it from the normal disposal process is more than the benefits. Also, a good amount of spent coffee grounds simply end up flushed out as wastewater.
But if that waste was going to a landfill instead of "the fields", then isn't it better if it gets put to a productive use rather than an unproductive one?