Sewage Discharge Given Ultimate BOD Calculator

Formula Used:

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

5 Days BOD:

kg/m³

Ultimate BOD:

kg/m³

Theoretical Oxygen Requirement:

kg/s

Volume of Wasted Sludge per day:

m³/s

MLSS in Returned or Wasted Sludge:

kg/m³

Influent BOD:

kg/m³

Effluent BOD:

kg/m³

Sewage Discharge given Ultimate BOD:

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1. What is Sewage Discharge Given Ultimate BOD?

Sewage Discharge given Ultimate BOD is the volume or rate of sewage flow that corresponds to a specified Ultimate Biochemical Oxygen Demand (BOD). It helps in determining the appropriate treatment capacity for wastewater systems.

2. How Does the Calculator Work?

The calculator uses the formula:

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

Where:

\( BOD5 \) — 5 Days BOD (kg/m³)
\( BODu \) — Ultimate 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)
\( Qi \) — Influent BOD (kg/m³)
\( Q \) — Effluent BOD (kg/m³)

Explanation: This formula calculates the sewage discharge rate based on the relationship between various BOD parameters and sludge characteristics in wastewater treatment.

3. Importance of Sewage Discharge Calculation

Details: Accurate calculation of sewage discharge is crucial for designing appropriate wastewater treatment systems, determining treatment capacity, and ensuring environmental compliance with discharge regulations.

4. Using the Calculator

Tips: Enter all required parameters in their respective units. Ensure that Influent BOD is greater than Effluent BOD, and all values are positive numbers within reasonable ranges for wastewater treatment applications.

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 total oxygen required for complete decomposition of organic matter over an infinite period.

Q2: Why is the 1.42 factor used in the calculation?
A: The factor 1.42 represents the oxygen equivalent of bacterial cell mass, accounting for the oxygen demand of biomass in the system.

Q3: What are typical values for MLSS in returned sludge?
A: MLSS values typically range from 4,000 to 12,000 mg/L (4-12 kg/m³) in returned activated sludge systems.

Q4: How does this calculation help in treatment plant design?
A: This calculation helps determine the required treatment capacity and ensures the system can handle the organic loading from the sewage discharge.

Q5: What units should be used for accurate results?
A: Consistent SI units must be used as specified in the input fields (kg/m³ for concentrations, m³/s for flow rates, kg/s for oxygen requirement).