How would you design a complete wastewater treatment plant for a city of 100,000 population?

Design approach: Calculate flow (135 lpcd x 100,000 x 1.5 peak factor = 20 MLD average, 30 MLD peak). Preliminary treatment: coarse screens, grit chambers (2 min detention). Primary treatment: rectangular clarifiers (2-3 hr HRT, 30 m3/m2/day overflow). Secondary treatment: activated sludge (6 hr HRT, MLSS 3000 mg/L, F/M 0.2-0.4) with final clarifiers. Tertiary: chlorination. Sludge: thickening, digestion (20 days), dewatering. Include equalisation, instrumentation, standby units, and effluent standards compliance (BOD <20, TSS <30 mg/L).