> [...] eaten and the nitrogen, phosphorous, potassium and other minerals are flushed into the rivers and oceans. What if we didn't though? Sewage could be tur

> [...] eaten and the nitrogen, phosphorous, potassium and other minerals are flushed into the rivers and oceans. What if we didn't though? Sewage could be turned into fertilizer, though probably not safely for growing food crops no matter how we treat it. Still, there must be some other way of putting the nutrients back in the local environment.