Ultimate Bod Given Oxygen Required In Aeration Tank Calculator

Formula Used:

\[ BOD_{uo} = \frac{BOD_5}{Q_s \times (Q_i - Q)} / (O_2 + (1.42 \times Q_w \times X_R)) \]

5 Days BOD (BOD₅):

mg/L

Sewage Discharge (Qₛ):

m³/s

Influent BOD (Qᵢ):

mg/L

Effluent BOD (Q):

mg/L

Theoretical Oxygen Requirement (O₂):

kg/s

Volume of Wasted Sludge per day (Q_w):

m³/s

MLSS in Returned or Wasted Sludge (X_R):

mg/L

Ultimate BOD (BOD_uo):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Ultimate BOD Given Oxygen Required?

Ultimate BOD represents the total amount of oxygen consumed by microorganisms during the complete biochemical oxidation of organic matter in a water sample. It provides a comprehensive measure of the organic pollution load in wastewater.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ BOD_{uo} = \frac{BOD_5}{Q_s \times (Q_i - Q)} / (O_2 + (1.42 \times Q_w \times X_R)) \]

Where:

\( BOD_5 \) — 5-day biochemical oxygen demand (mg/L)
\( Q_s \) — Sewage discharge flow rate (m³/s)
\( Q_i \) — Influent BOD concentration (mg/L)
\( Q \) — Effluent BOD concentration (mg/L)
\( O_2 \) — Theoretical oxygen requirement (kg/s)
\( Q_w \) — Volume of wasted sludge per day (m³/s)
\( X_R \) — MLSS in returned or wasted sludge (mg/L)

Explanation: This formula calculates the ultimate BOD by considering the oxygen demand relative to the sewage characteristics and treatment process parameters.

3. Importance of Ultimate BOD Calculation

Details: Accurate ultimate BOD estimation is crucial for designing wastewater treatment systems, determining treatment efficiency, and assessing the environmental impact of discharged effluent.

4. Using the Calculator

Tips: Enter all required parameters with appropriate units. Ensure values are positive and within reasonable ranges for accurate results.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between BOD₅ and Ultimate BOD?
A: BOD₅ measures oxygen demand over 5 days, while Ultimate BOD represents the complete oxygen demand for full organic matter decomposition.

Q2: Why is 1.42 used in the formula?
A: The factor 1.42 represents the oxygen equivalent of bacterial cells, accounting for the oxygen demand of biomass.

Q3: What are typical Ultimate BOD values?
A: Values vary widely depending on wastewater source, but typically range from 100-400 mg/L for domestic sewage.

Q4: How does temperature affect BOD calculations?
A: BOD reaction rates increase with temperature, typically following Arrhenius kinetics with temperature coefficients around 1.047.

Q5: When should this calculation be used?
A: This calculation is particularly useful for aeration tank design and optimization in activated sludge wastewater treatment systems.