one of the solution to the problem of water conservation is to recycle wastewater. when you flush the toilets at Stensund Folk College near Stockholm Sweden you help feed the fish. the school treats the wastewater in a greenhouse where it is then used to provide water to plants and fish in Lima Peru ponds full of algae and other small organisms clean up the wastewater. after 20 days it is safe for reuse. Currently many factories hotel chains and apartment buildings aroud the world are installing water recycling systems