The easiest fix for you where ...
Published by Terry Scheurman, President at Applied Specialties, Inc.
The easiest fix for you where everything else downstream doesn't get screwed up is to use a blended lime slurry with calcium nitrate. Feed it to get the pH to 7.4 to 7.7. If it goes higher, you will just be wasting chemical. It will prevent H2S from building in the gas space and the nitrate will slow the reactions causing the H2S. Cheap and easy fix. Install an H2S monitor and you can actually see the H2S level drop. You should have an H2S monitor for employee safety anyway. You don't need anything fancy to see if it works. A BOD bottle, your WW and a small chemical sample plus an H2S probe. No magic. H2S monitor and a small chemical metering pump.