"Major cities in each state... each one pumps their sewerage... or treated water into the sea"
Melbourne treats its sewerage at the Werribee Farm treatment-plant lagoons and has done as long as I can recall. They now remove the nitrogen content and flood irrigate with the recycled water and sell recycled water.
The "Metro Farm" is quite a large acreage west of Melbourne and had a small village there once called Corcoroc I believe.
