Is there a publically available database of microbes that details what their wastes and food sources are
You could try to look into the kegg database. It's main purpose is to describe biochemical pathways, but it also has information on which species actually have these pathways (not sure how well this annotation is for bacteria though).

You should be able to pinpoint a few key pathways that start on free ammonia or have sulphuric acid as a sink/endpoint and then check for all annotated species. I wouldnt expect such lists to be comprehensive, but it should give you at least a starting point.

As an example the Nitrification and Anammox sub-pathways of the Nitrogen-metabolism page show direct usage/incorporation of free ammonia. If you click on some of the enzymes/genes (the boxes with numbers) and follow through to the 'taxonomy' box under genes, you'll get a list of some bacteria species each.