you could add some fish to your water reclamation tank for a small aquaponics system. Grow a few plants to feed the fish and this forms a closed system. There is no need to fertilize, the fish do it for you! Permaculture at its finest!
Mine should be up and running soon! Got an apartment with limited space? A Hydroponic window farm is for you. All you need are plastic bottles with cuts in them, plants, soil, and some supports to hold it to a PVC frame.