Formula Used:
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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.
The calculator uses the formula:
Where:
Explanation: The formula adjusts the deoxygenation constant measured at any temperature to the standard 20°C value using the temperature correction factor.
Details: Standardizing the deoxygenation constant to 20°C allows for consistent comparison of BOD rates across different water temperatures and locations.
Tips: Enter the deoxygenation constant at your measured temperature and the water temperature in °C. Both values must be valid (KD(T) > 0).
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.