Here is an amazing design that requires no automation whatsoever and allows for usable drinking by distilling problem water into a form we can ingest. It is called the "Water Cone." I found it at Not-Cot this afternoon.
There are only two ways to desalinate slat water; distilling it or running it through a process of complex filtration.
This device uses the former to create drinkable water by distilling it. It works like an ad hoc greenhouse. You pour the water into the bottom pan, the water evaporates due to the greenhouse heat and through condensation collects along the sides of the "window" and collects into a safe area to provide 1.6 liters of distilled water. (Australia could use a few million of these.)
Here is a link to the Water Cone site with a demonstration on the photos page as to how it works: [Link] Here is the home page: [Link]