WASTEWATER By Rick Lallish
What condition occurs when the sludge age advances and there is less food available per bacteria?
A. Flocculation
B. Nocardia filaments
C. Excessive white foam
D. Endogenous respiration
Answer: D. A portion of the bacteria can be lost due to endogenous respiration at high sludge ages. This is due to the lack of food available or an unbalanced food-to-microorganism (F/M) ratio. The bacteria will consume their own cell mass and exopolymer to survive. This will provide food for the other bacteria as well. Understanding the natural cycle of life and conditions in an activated sludge treatment process gives operators useful knowledge for
