What does SRT stand for and why is it important in activated sludge?

• A. Solids Removal Time; time to remove solids.
• B. Solids Retention Time; the average time biomass remains in the system, influencing treatment efficiency and sludge characteristics.
• C. System Retention Tolerance; maximum tolerance for solids.
• D. Sludge Return Time; time to return sludge.

Answer: (B)