Hi! I am also familiar with this situation. My corporation also has a water treatment plant. It perfectly cleans sewage from all contaminants. The only problem is the ingress of salt into the water. If the water contains salt (chlorides), we cannot clean it. To do this, you need to install a desalination plant. This is a relatively small investment. Talks about this installation have been going on since 2000, for 22 years no one has allocated funds for its purchase.