There are ion exchange bead bed filters that are used by 'washless' commercial photo processors machines to deal with their taank overflow fliuds disposal.
They filter out low volume low thoisulphate/sliver bearing waters so they are acceptable to send them down the drain and be regulatory compliant.
I had one given to me and discarded it but the thing looked a bit like a toilet tank on a stand.
There was an electronic sensor that measured the ionic conductivity of the discharge water to tell you when you had loaded up the bead bed and were no longer sending out clean water.
There was a service company that renewed the bead cartridge to recover the silver, and you mailed them back and forth to keep a clean one ready to go.