Effluent BOD Given Oxygen Required In Aeration Tank Calculator

Formula Used:

\[ Q_o = Q_i - \frac{f \times (O_2 + (1.42 \times Q_w \times X_R))}{SF} \]

Influent BOD (Q_i):

kg/m³

Ratio of BOD to Ultimate BOD (f):

Theoretical Oxygen Requirement (O₂):

kg/s

Volume of Wasted Sludge per day (Q_w):

m³/s

MLSS in Returned or Wasted Sludge (X_R):

kg/m³

Sewage Flowrate (SF):

m³/s

Effluent BOD (Q_o):

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1. What is Effluent BOD Given Oxygen Required?

Effluent BOD Given Oxygen Required in Aeration Tank is the amount of biodegradable organic matter in the treated wastewater after accounting for the oxygen requirements in the aeration process.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Q_o = Q_i - \frac{f \times (O_2 + (1.42 \times Q_w \times X_R))}{SF} \]

Where:

\( Q_o \) — Effluent BOD (kg/m³)
\( Q_i \) — Influent BOD (kg/m³)
\( f \) — Ratio of BOD to Ultimate BOD
\( O_2 \) — Theoretical Oxygen Requirement (kg/s)
\( Q_w \) — Volume of Wasted Sludge per day (m³/s)
\( X_R \) — MLSS in Returned or Wasted Sludge (kg/m³)
\( SF \) — Sewage Flowrate (m³/s)

Explanation: This formula calculates the effluent BOD by subtracting the oxygen consumption component from the influent BOD, accounting for sludge wastage and oxygen requirements.

3. Importance of Effluent BOD Calculation

Details: Accurate effluent BOD calculation is crucial for assessing wastewater treatment plant performance, ensuring compliance with discharge regulations, and optimizing treatment processes.

4. Using the Calculator

Tips: Enter all values in the specified units. Ensure influent BOD and sewage flowrate are positive values. All other parameters should be non-negative values.

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 biomass, accounting for the oxygen required to oxidize the volatile suspended solids.

Q2: How is the ratio of BOD to Ultimate BOD determined?
A: This ratio is typically determined experimentally and represents the relationship between 5-day BOD and ultimate BOD for the specific wastewater.

Q3: What are typical values for MLSS in returned sludge?
A: MLSS values in returned sludge typically range from 4,000 to 12,000 mg/L (4-12 kg/m³), depending on the treatment process and sludge characteristics.

Q4: Why is theoretical oxygen requirement important?
A: Theoretical oxygen requirement helps determine the amount of oxygen needed for biological oxidation of organic matter, which is essential for proper aeration system design and operation.

Q5: How does sludge wastage affect effluent BOD?
A: Sludge wastage removes biomass from the system, which affects the oxygen demand and ultimately influences the effluent BOD concentration.