Other than the already ...
Published by Brent Brady, Operations Supervisor (Wastewater) at CH@M-Hill
Other than the already mentioned ideas, here are a few more.
Introduction of metered bi-oxide to wet wet or waste stream.
Bleach drip feed will work
Normal aeration of a wet well has worked in some places I have been
In another place we put in a smaller pump as a lead. This allowed for longer, and more continual, pump draws that minimized the time that the flow was allowed to be stagnate and septic.
Have also introduced an additional water flow (small wet-well with low over night flows) to give faster pump cycling. This left little time for the build up of H2S and minimized the order complaints.
Just a few thoughts. I would have to know more about the specifics of the locations, as every one will have its own issues.