RAS sample floats
You may be running too high of a sludge age for your plant. Determine the sludge age and increase sludge blowdown if required. Check your sludge blanket depth in the clarifier as the blanket may be too high.This is assuming that this is a straight aeration digestion plant and the sludge is lifting due to denitrification. If you are operating with a anoxic section you need to balance the retention times through the process.