We have an electrically operated RO system in our RV. We are able to provide power with our solar array as well as run all of our other needed electrical stuff. The process is slow, but it provides for our needs.

The system is one of the under sink models purchased from Sams Club. The brine is fed back into the supply tank. This method has worked for years and we have the membrane checked abour once a year. Had to replace the membrane once after several years because of damage done to it during handling. It was still functioning well.

RO is nice in the southwestern US as there are many dissolved salts in the water. Now I hate to drink anything else.