Biochemical Wastewater Assessment & Design

BIOCHEMICAL WWTP · ASM FRAMEWORK

Fast scoping for activated sludge

This page applies steady-state yield–decay relationships consistent with IWA ASM thinking and Metcalf & Eddy-style textbook simplifications (single well-mixed aerobic volume). Effluent shortcuts reference China GB 18918, the EU UWWTD order of magnitude, and typical US secondary limits — always supersede with your permit.

DESIGN INPUTS

Influent / effluent / process

All calculations run locally in your browser. Use Calculate for results and Print report for an A4 layout (save as PDF from the print dialog).

0. Report header

Project name Assessment date

1. Flow

Design flow Qm³/d

2. Influent

CODmg/L BOD₅mg/L NH₃-Nmg/L TNmg/L TPmg/L TSSmg/L pH

3. Effluent targets

Quick fill (effluent columns only, indicative benchmarks):

CODmg/L BOD₅mg/L NH₃-Nmg/L TNmg/L TPmg/L TSSmg/L pH

4. Process design

SRT θd Aerobic MLSS Xmg/L Temperature T°C Yield Ykg VSS/kg BOD₅ Denitrification COD/N ratio rkg COD/kg NOx-N Include nitrification oxygen (4.57 kg O₂ per kg NH₃-N removed)

Equation summary: V = Y·θ·Q·ΔBOD₅ / [X·(1+k_d·θ)]; oxygen includes carbon oxidation and optional nitrification; k_d is temperature-corrected. This aligns conceptually with heterotrophic yield/decay in IWA ASM1/ASM3 without matrix solution. Glucose dose uses ΔTN and COD/N to estimate external COD, then divides by the theoretical COD of anhydrous glucose (192/180); it does not replace pilot data or full plant nitrogen balances.

Fast scoping for activated sludge

Influent / effluent / process

Need BioWin-level modelling or BNR layout?