I’m not an expert, but couldn’t you pump the brine into a shallow reservoir and evaporate the water off, similar to how sea salt is made? If there isn’t a significant amount of contaminants, you could theoretically just sell that as well, but even if not, the solid salt is a lot easier to deal with
I don’t know of any graphical tools that let you do this, but generally, if you want to search for specific terms/times/commands or anything of that sort, piping journalctl into grep (and optionally grep into less) is pretty effective at finding stuff.