Lot of good points made here. ...
Published by Kenneth Keil, P.E.
Lot of good points made here. Verify the influent loading hasn't changed that much. Was the WAS rate increased? If it was, decrease it but by no more than 10 % per week. If the WAS rate wasn't decreased and you are still losing MLSS, then decrease WAS rate by no more than 10% per week. Have you done a microbiological analysis (speciation)? Are the microbes essentially the same before the issue arose or not? If different, must determine why the change. Has something entered the RAS piping from the clarifier in which the flow is partially blocked? Did something like a bucket fall in the clarifier?