I helped some chappies out lately with some illustrations for a council funded website informing people on how to get rid of all kinds of stuff without just throwing it away - expanding the lifespan of the item, giving it another life/purpose, what-have-you. As well as being a directory of places that will deal with your refuse/junk, it's also a directory of places who'll give you stuff like horse poo, bokashi... that sort of stuff.
So I did three icons - one for organic waste, one for inorganic waste, and one for community groups. Here they are:
Here are all the icons outside of their little clusters, including some of the ones I made but didn't end up using. I particularly liked the t-shirt.