Easily create a community initiative where people can take plastic and recycle it into building blocks for kids using a microwave and a blender. Can also recycle them into tubing for aquaponic gardens, and thus children will be learning engineering a
Robert, have you heard of aquaponics? It is aquaculture + hydroponics. You cannot grow vegetables in soil + have the water cycle back to the fish... no soil is used in a closed-loop system with fish. Thus, there is no composting used in aquaponic systems.
However, if you wanted to use the compost to grow algae/duckweed growing separately, which would be used as food for the fish, thus helping create a more sustainable modular system.
One big problem is there won't be enough space for necessary protein production. Thus you should do aquaponics as well. Another one is you could still suffer from many plant diseases because of growing in soil, where hydro/aquaponics are better. (unless you have experience/research that says this isn't that big of a problem). Check out http://Sustainiverse.org