The paper discusses two relatively new concepts to help operators diagnose problems and effectively control the activated sludge process performance. The trend chart display of Dynamic Sludge Age (DSA) values helps operators visualize how and why the sludge wasting program is affecting mixed liquor sludge quality. Accordingly, it helps determine the day-to-day wasting adjustments needed to restore or maintain good sludge quality. The calculated final clarifier Sludge Blanket Thickness (BLT) versus Clarifier Sludge Flow Percentage (CSP) curve shows the approximate trend of blanket thickness responses to clarifier sludge flow control. The information developed from these two concepts can help determine the proper sludge wasting and the return sludge flow rates needed to meet the interrelated requirements of the variable sewage flows, organic loadings, and sludge quality characteristics.