This is one step further than How do I remove musty smell in coat closet?.
There was a sewage backflow under my kitchen island :( I fixed that problem, but now there's a musty smell in one of the island's drawers.
I removed the built-in stove so I can see the sewage and the subfloor, broke one slab and removed 2 buckets of sand beneath the subfloor around the sewage pipe where the dampness had been. I've now been airing it for a week (I also put a small heater there).
NOW: do I just put new sand, and put the stove back in? Or would you also cover the subfloor hole with a thin layer of cement?
Or is there something else that you would try?