┌──────────────────────────────────────────────┐ │ INFLUENT WASTEWATER │ │ (Flow rates, COD/BOD5, Nitrogen, Temp) │ └──────────────────────┬───────────────────────┘ │ ▼ ┌──────────────────────────────────────────────┐ │ 1. BIOLOGICAL REACTOR (AERATION) │ │ • Aerobic Sludge Age Calculation │◄────────┐ │ • Carbon Degradation, Nitrification │ │ │ • Oxygen Transfer Rate (OTR) Sizing │ │ └──────────────────────┬───────────────────────┘ │ Activated │ Mixed Liquor │ Sludge │ Suspended Solids (MLSS) │ Return ▼ │ Loop ┌──────────────────────────────────────────────┐ │ │ 2. SECONDARY SETTLING TANK │ │ │ • Solids Loading Rate & Sludge Volume Index │ │ │ • Clear Water Separation (h1 - h4 Zones) │─────────┘ └──────────────────────┬───────────────────────┘ │ ▼ ┌──────────────────────────────────────────────┐ │ TREATED EFFLUENT │ └──────────────────────────────────────────────┘ 1. Dimensioning the Biological Reactor
Pre-denitrification volume fraction ( f_D ) is determined from: atv dvwk a 131 epdf top
Includes standardized values for oxygen transfer, chemical oxygen demand (COD), and inhabitant-specific pollutant loads (typically 60g BOD₅ per person per day). Dynamic Simulation: This includes calculating the daily BOD₅ load (
The standard reflects higher treatment requirements by setting the dimensioning temperature for nitrogen removal at T=12°C (increased from 10°C in previous versions). chemical oxygen demand (COD)
Once you have the top PDF, maximize its value:
Before sizing the tanks, the standard defines the crucial hydraulic and organic loads. This includes calculating the daily BOD₅ load ( Bd,BODcap B sub d comma cap B cap O cap D end-sub