We don't have any trouble with the bilge smell in the boat, for two reasons.
We are not terribly fussy about what goes down the drain, but we do always was dishes with the strainer in the drain. We also have a sink trap that catches other "chunks" under the sink in the galley. I wouldn't say we were any more careful about this than we would be in home without a garbage grinder.
We also have "U" traps made of three elbows and tubing where the drains empty into the sump. Always full of water, they prevent the backup of any engine room odors into the cabin.
Bleach is something I don't use on the boat at all. It is just too corrosive to too many things.
I clean the sump when it looks like it has accumulated enough "gunk" to need it. It's not very often it needs it. I look whenever I am in the engine room, but I don't have the cleaning on my routine maintenance schedule.
Key West, FL