Design & Humanure
It is often what is closest to us that offer the best lessons. In the realm of design, looking at how we deal with human output (aka shit) reveals our thought patterns and how our designs follows our views.
The current situation: In our culture, we operate from several assumptions - all revealing a fragmented and dualistic worldview. We think there is something called "away". We have phobias regarding our body functions. We operate from an idea of unlimited inflow of essentials. All this makes up our current system: We take purified water, deposit our feces and urine in it, flush it down through a intricate system of pipes, into a wastewater plant (in the best case), then into the ocean. In the process, we take a valuable resource (clean drinking water) and soil it, we make ourselves dependent on an expensive infrastructure, and we let go of an invaluable resource.
How it can be: Operating from a different view of the world - one that acknowledges interconnections, we arrive at different solutions. The Earth is a closed loop system, there is no "away". It is more efficient to close our loops as locally as possible. We can set up simple composting toilet system - odor free, low in cost, and simple in operation. These allows us to keep our water clean for drinking and food. They also provide us with invaluable nutrients for later growing foods. We close one of the many loops we are part of - nutrients flow into plants, our bodies, our feces and urine, into compost, and back into plants. A beautiful and efficient system.