A portion of the settled sludge is returned to the aeration tank to maintain the microbial population. 4. Advanced Biological Technologies
$$\eta = \fracBOD_in - BOD_outBOD_in \times 100$$ stp design calculation
Population Equivalent (PE): [ 1000 ] Per capita water supply (LPCD): [ 135 ] Sewage factor (%): [ 80 ] A portion of the settled sludge is returned
After aeration, the water enters a clarifier (sedimentation tank) for solid-liquid separation. 000 liters/day × 0.8 = 48
where: $V$ = aeration tank volume (m³) $L$ = BOD5 loading rate (kg/m³/d) $t$ = detention time (h)
$$ADF = P \times q \times (1 + I)$$
Example: 60,000 liters/day × 0.8 = 48,000 liters/day (or 48 KLD). 2. Determine Design Peak Flow