1. What is Time given Organic Matter Present at Start of BOD Calculator?

Definition: This calculator determines the time required for biochemical oxygen demand (BOD) based on the deoxygenation constant, oxygen equivalent, and initial organic matter concentration.

Purpose: It helps environmental engineers and wastewater treatment professionals analyze the oxygen demand over time in water bodies.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( t \) — Time in days
• \( K_D \) — Deoxygenation constant (per day)
• \( L_t \) — Oxygen equivalent (kg/m³)
• \( L_s \) — Organic matter at start (kg/m³)

Explanation: The formula calculates the time required for the organic matter to reach a certain oxygen equivalent level based on the deoxygenation rate.

3. Importance of BOD Time Calculation

Details: Accurate time estimation helps in designing wastewater treatment systems and understanding the oxygen demand in natural water bodies.

4. Using the Calculator

Tips: Enter the deoxygenation constant (default 0.00000266 per day), oxygen equivalent (default 0.00021 kg/m³), and initial organic matter (default 0.04 kg/m³). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the deoxygenation constant?
A: It's a rate constant that describes how quickly oxygen is consumed by microorganisms decomposing organic matter.

Q2: What are typical values for K_D?
A: Typically ranges from 0.05 to 0.4 per day for domestic sewage at 20°C.

Q3: How do I determine L_t and L_s?
A: These are measured through laboratory BOD tests - L_s is initial concentration, L_t is concentration at time t.

Q4: Why is the formula logarithmic?
A: The BOD reaction follows first-order kinetics, resulting in an exponential decay relationship.

Q5: How does temperature affect the calculation?
A: Higher temperatures increase K_D. The calculator uses values at a specific temperature (typically 20°C).