BOD5 Given Oxygen Required In Aeration Tank Calculator

Formula Used:

\[ BOD5 = BODu \times \frac{Qs \times (Qi - Q)}{O2 + (1.42 \times Qw \times XR)} \]

Ultimate BOD (BODu):

kg/m³

Sewage Discharge (Qs):

m³/s

Influent BOD (Qi):

kg/m³

Effluent BOD (Q):

kg/m³

Theoretical Oxygen Requirement (O2):

kg/s

Volume of Wasted Sludge per day (Qw):

m³/s

MLSS in Returned or Wasted Sludge (XR):

kg/m³

BOD5 Given Oxygen Required In Aeration Tank:

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1. What is BOD5 Given Oxygen Required In Aeration Tank?

BOD5 Given Oxygen Required In Aeration Tank represents the amount of oxygen required by aerobic microorganisms to decompose organic matter in water over a period of five days at a temperature of 20°C in an aeration tank system.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ BOD5 = BODu \times \frac{Qs \times (Qi - Q)}{O2 + (1.42 \times Qw \times XR)} \]

Where:

\( BODu \) — Ultimate BOD (kg/m³)
\( Qs \) — Sewage Discharge (m³/s)
\( Qi \) — Influent BOD (kg/m³)
\( Q \) — Effluent BOD (kg/m³)
\( O2 \) — Theoretical Oxygen Requirement (kg/s)
\( Qw \) — Volume of Wasted Sludge per day (m³/s)
\( XR \) — MLSS in Returned or Wasted Sludge (kg/m³)

Explanation: This formula calculates the five-day biochemical oxygen demand based on the oxygen requirements and sludge characteristics in an aeration tank system.

3. Importance of BOD5 Calculation

Details: Accurate BOD5 calculation is crucial for designing and operating wastewater treatment plants, determining aeration requirements, and ensuring proper treatment efficiency.

4. Using the Calculator

Tips: Enter all values in the specified units. Ensure all inputs are positive values and the denominator doesn't equal zero to avoid division errors.

5. Frequently Asked Questions (FAQ)

Q1: What is the significance of the 1.42 factor?
A: The 1.42 factor represents the oxygen equivalent of bacterial cells, accounting for the oxygen demand of biomass.

Q2: How does this differ from standard BOD5 measurement?
A: This calculation specifically addresses the oxygen requirement in aeration tanks, considering sludge characteristics and system parameters.

Q3: What are typical values for MLSS in returned sludge?
A: MLSS values typically range from 2000-8000 mg/L (2-8 kg/m³) in activated sludge systems.

Q4: When is this calculation most useful?
A: This calculation is particularly useful for wastewater treatment plant design, optimization, and operational control.

Q5: What precautions should be taken with this calculation?
A: Ensure all units are consistent and verify that input values represent actual operating conditions of the treatment system.