1. What is Organic Loading using Hydraulic Retention Time?

Definition: This calculator determines the organic loading rate in wastewater treatment systems based on influent substrate concentration and mixed liquor volatile suspended solids (MLVSS).

Purpose: It helps wastewater treatment professionals assess the biological treatment capacity and optimize process performance.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( VL \) — Organic Loading (kg/m³)
• \( So \) — Influent Substrate Concentration (kg/m³)
• \( Xa \) — MLVSS (Mixed Liquor Volatile Suspended Solids) (kg/m³)

Explanation: The organic loading rate represents the amount of organic matter applied to the treatment system per unit of active biomass.

3. Importance of Organic Loading Calculation

Details: Proper organic loading estimation ensures efficient biological treatment, prevents system overload, and maintains treatment process stability.

4. Using the Calculator

Tips: Enter the influent substrate concentration (So) in kg/m³ and MLVSS (Xa) in kg/m³ (default 2.5 kg/m³). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical MLVSS value for activated sludge systems?
A: Most activated sludge systems maintain MLVSS between 1.5-3.5 kg/m³, with 2.5 kg/m³ being a common design value.

Q2: How does organic loading affect treatment performance?
A: Higher loading rates may lead to incomplete treatment, while lower rates may result in endogenous respiration of biomass.

Q3: What's the relationship between organic loading and hydraulic retention time?
A: Longer HRT typically allows for lower organic loading rates, as microorganisms have more time to degrade the organic matter.

Q4: How do I measure influent substrate concentration?
A: It's typically measured as BOD (Biochemical Oxygen Demand) or COD (Chemical Oxygen Demand) in mg/L or kg/m³.

Q5: What happens if organic loading is too high?
A: Excessive organic loading can lead to oxygen depletion, poor settling, and potential system failure.