1. What is Deoxygenation Constant at 20°C?

Definition: The deoxygenation constant at 20°C (KD(20)) is a measure of the rate at which oxygen is consumed by microorganisms in water at the standard temperature of 20°C.

Purpose: It's used in water quality modeling to predict biochemical oxygen demand (BOD) and assess the impact of organic pollutants on water bodies.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( KD(20) \) — Deoxygenation constant at 20°C (1/s)
• \( KD(T) \) — Deoxygenation constant at temperature T (1/s)
• \( T \) — Water temperature (°C)
• 1.047 — Temperature correction coefficient

Explanation: The formula adjusts the deoxygenation constant measured at any temperature to the standard 20°C value using the temperature correction factor.

3. Importance of KD(20) Calculation

Details: Standardizing the deoxygenation constant to 20°C allows for consistent comparison of BOD rates across different water temperatures and locations.

4. Using the Calculator

Tips: Enter the deoxygenation constant at your measured temperature and the water temperature in °C. Both values must be valid (KD(T) > 0).

5. Frequently Asked Questions (FAQ)

Q1: Why is 20°C used as the standard temperature?
A: 20°C is a commonly used reference temperature in water quality studies as it represents typical environmental conditions.

Q2: What's the typical range for KD values?
A: For most natural waters, KD(20) ranges from 0.05 to 0.3 per day (5.79×10⁻⁷ to 3.47×10⁻⁶ per second).

Q3: Where does the 1.047 coefficient come from?
A: This empirical coefficient accounts for the temperature dependence of microbial activity in water.

Q4: How do I measure KD(T) in the field?
A: KD(T) is typically determined through BOD tests conducted at the field temperature.

Q5: Can this formula be used for any temperature?
A: The formula works best for temperatures between 0-30°C. Outside this range, microbial activity may follow different patterns.