Oxygen Required In Aeration Tank Given Ultimate BOD Calculator

Formula Used:

\[ Oxygen\ Required = \frac{Sewage\ Discharge \times (Influent\ BOD - Effluent\ BOD)}{5\ Days\ BOD / Ultimate\ BOD} - 1.42 \times Volume\ of\ Wasted\ Sludge\ per\ day \times MLSS\ in\ Returned\ or\ Wasted\ Sludge \]

\[ Or = \frac{Q_s \times (Q_i - Q)}{BOD_5 / BOD_u} - 1.42 \times Q_w \times X_R \]

Sewage Discharge (Q_s):

m³/s

Influent BOD (Q_i):

kg/m³

Effluent BOD (Q):

kg/m³

5 Days BOD (BOD₅):

kg/m³

Ultimate BOD (BOD_u):

kg/m³

Volume of Wasted Sludge per day (Q_w):

m³/s

MLSS in Returned or Wasted Sludge (X_R):

kg/m³

Oxygen Required (Or):

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1. What is Oxygen Required in Aeration Tank?

Oxygen Required is the amount of oxygen needed to sustain biological processes in an aeration tank, which is a critical component of wastewater treatment systems. It ensures proper breakdown of organic matter by microorganisms.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Or = \frac{Q_s \times (Q_i - Q)}{BOD_5 / BOD_u} - 1.42 \times Q_w \times X_R \]

Where:

\( Q_s \) — Sewage Discharge (m³/s)
\( Q_i \) — Influent BOD (kg/m³)
\( Q \) — Effluent BOD (kg/m³)
\( BOD_5 \) — 5 Days BOD (kg/m³)
\( BOD_u \) — Ultimate BOD (kg/m³)
\( Q_w \) — Volume of Wasted Sludge per day (m³/s)
\( X_R \) — MLSS in Returned or Wasted Sludge (kg/m³)

Explanation: The formula calculates the oxygen requirement by considering the BOD removal and the oxygen consumed in sludge wasting.

3. Importance of Oxygen Calculation

Details: Accurate oxygen calculation is crucial for designing efficient aeration systems, ensuring proper treatment, and optimizing energy consumption in wastewater treatment plants.

4. Using the Calculator

Tips: Enter all values in appropriate units. Sewage discharge and sludge volume should be in m³/s, BOD values in kg/m³. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why is oxygen required in aeration tanks?
A: Oxygen is required to support aerobic microorganisms that break down organic matter in wastewater, ensuring effective treatment.

Q2: What is the difference between BOD₅ and Ultimate BOD?
A: BOD₅ measures oxygen demand over 5 days, while Ultimate BOD measures the total oxygen required to decompose all organic matter.

Q3: How does sludge wasting affect oxygen requirement?
A: Sludge wasting removes microorganisms from the system, reducing the oxygen demand for endogenous respiration.

Q4: What factors can affect oxygen requirement calculations?
A: Temperature, wastewater characteristics, microbial population, and system design can all affect oxygen requirements.

Q5: How often should oxygen requirements be calculated?
A: Regular calculations are needed, especially when wastewater characteristics change or during system optimization.