A new 1.5 MGD activated sludge plant designed from scratch for a 15,000-person town — worked design flow, F/M-based aeration basin sizing, peak-flow-governed clarifier sizing, blower sizing, and an effluent quality check against NPDES permit limits.
The project brief: a town of 15,000 people annexing into a regional sewer district needs a complete-mix activated sludge wastewater treatment plant designed from the ground up, discharging under an NPDES permit. With no existing infrastructure to audit, every unit process — headworks, aeration basin, secondary clarifiers, blowers, and disinfection — has to be sized from the design population and flow forward, then checked against the permit before construction.
This module works the full design chain the way a real process engineer would: design flow and BOD loading calculations, an F/M-driven aeration basin volume cross-checked against hydraulic retention time, a secondary clarifier sizing exercise that shows peak flow — not average flow — actually governs, RAS recycle ratio and blower sizing from an oxygen-demand calculation, and a final effluent quality check against the 30/30 permit standard. The full worked numbers, complete bill of materials, and finished design reasoning are part of the unlocked module below.