A blower tripped on a Friday and nobody was on site until Monday. What we found in the tank, why BOD recovers in days and ammonia in weeks, what we did in order, and the design question underneath it.
A healthy sewage treatment plant smells like wet soil. When it smells like rotten eggs, ammonia, or spoiled food, it is telling you where to look, usually weeks before the lab report does. Field notes on reading an STP by smell, including the food processing plant that taught me the hard way.
