The diagrams displays the present Australian’s water supply system as well as its future one.
The present system has four main parts: the dam/storage, the city composed of households, factories and shops, the water treatment plant and the river. Here is how the system works: pure water goes from the dam/storage into the city to be consumed by households, factories and shops. From there, wasted water is transferred to a water treatment plant that eventually releases it into the river. Notice that this treated water is still considered as waste water. Additionally, storm water coming from the city is also thrown into the river.
The future system does not involve the river. The waste water is going from the city to the water treatment plant, where it is properly treated. Then, the treated water that has become pure water is re-injected into the city for its use by households, shops and factories. The storm water coming from the city is also send to the treatment plant and eventually transferred back to the city for consumption purposes.