Influent BOD Given Oxygen Required In Aeration Tank Calculator

Formula Used:

\[ \text{Influent BOD} = \text{Effluent BOD} + \frac{\text{Ratio of BOD to Ultimate BOD} \times (\text{Theoretical Oxygen Requirement} + (1.42 \times \text{Volume of Wasted Sludge per day} \times \text{MLSS in Returned or Wasted Sludge}))}{\text{Sewage Discharge}} \]

Effluent BOD:

kg/m³

Ratio of BOD to Ultimate BOD:

Theoretical Oxygen Requirement:

kg/s

Volume of Wasted Sludge per day:

m³/s

MLSS in Returned or Wasted Sludge:

kg/m³

Sewage Discharge:

m³/s

Influent BOD:

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1. What is Influent BOD Calculation?

The Influent BOD calculation determines the total amount of biodegradable organic matter in the incoming sewage to an aeration tank. This is crucial for designing and operating wastewater treatment systems effectively.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

Effluent BOD — Amount of biodegradable organic matter in treated wastewater (kg/m³)
Ratio of BOD to Ultimate BOD — Ratio of 5-day BOD to ultimate BOD
Theoretical Oxygen Requirement — Calculated oxygen needed for oxidation (kg/s)
Volume of Wasted Sludge per day — Daily sludge removal rate (m³/s)
MLSS in Returned or Wasted Sludge — Mixed liquor suspended solids concentration (kg/m³)
Sewage Discharge — Flow rate of sewage discharge (m³/s)

Explanation: This formula accounts for the oxygen demand from both the wastewater treatment process and the sludge management system.

3. Importance of Influent BOD Calculation

Details: Accurate influent BOD calculation is essential for proper sizing of aeration systems, determining treatment efficiency, and ensuring compliance with environmental regulations for wastewater discharge.

4. Using the Calculator

Tips: Enter all values in the specified units. Ensure all inputs are positive values, with Sewage Discharge and Ratio of BOD to Ultimate BOD being greater than zero for valid calculations.

5. Frequently Asked Questions (FAQ)

Q1: Why is the ratio of BOD to ultimate BOD important?
A: This ratio helps convert between the 5-day BOD test results and the ultimate oxygen demand, providing a more complete picture of the organic loading.

Q2: What factors affect the theoretical oxygen requirement?
A: The oxygen requirement depends on the type and concentration of organic matter, temperature, and the efficiency of the biological treatment process.

Q3: How does MLSS concentration impact the calculation?
A: Higher MLSS concentrations indicate more biomass in the system, which affects both oxygen demand and sludge production rates.

Q4: When should this calculation be performed?
A: This calculation should be done during system design, operational optimization, and when troubleshooting treatment performance issues.

Q5: Are there limitations to this equation?
A: The equation assumes steady-state conditions and may need adjustment for systems with significant variations in loading or unusual wastewater characteristics.