1. What is Deoxygenation Constant?

Definition: The deoxygenation constant (K_D) represents the rate at which oxygen is consumed during the decomposition of organic matter in water.

Purpose: It's a crucial parameter in water quality modeling, particularly in calculating biochemical oxygen demand (BOD) in wastewater treatment.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( K_D \) — Deoxygenation constant (1/day)
• \( t \) — Time period (days)
• \( Y_t \) — Organic matter oxidised (mg/L)
• \( L_s \) — Organic matter at start (mg/L)

Explanation: The formula calculates the rate constant based on the proportion of organic matter that has been oxidized over a given time period.

3. Importance of Deoxygenation Constant

Details: Accurate determination of K_D helps in designing wastewater treatment systems, predicting oxygen depletion in water bodies, and assessing water quality.

4. Using the Calculator

Tips: Enter the time period in days, amount of organic matter oxidised (must be less than starting amount), and initial organic matter concentration. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What are typical values for K_D?
A: For domestic sewage, K_D typically ranges from 0.1 to 0.4 per day at 20°C.

Q2: How does temperature affect K_D?
A: K_D increases with temperature, typically following the Arrhenius relationship with a θ value of about 1.047.

Q3: What if my oxidised matter equals starting matter?
A: The calculation becomes undefined as you'd be taking log10(0). This suggests complete oxidation has occurred.

Q4: Can this be used for natural water bodies?
A: Yes, but values may differ from wastewater as natural systems have different organic matter composition.

Q5: How precise should my measurements be?
A: For reliable results, measurements should be precise to at least 3 significant figures.