Average Daily Influent Flow Rate Given Theoretical Oxygen Requirement Calculator

Formula Used:

\[ Q_a = \frac{(O_2 + (1.42 \times P_x)) \times f}{8.34 \times (S_o - S)} \]

Theoretical Oxygen Requirement (O₂):

kg/s

Net Waste Activated Sludge (Pₓ):

kg/s

BOD Conversion Factor (f):

Influent Substrate Concentration (Sₒ):

kg/m³

Effluent Substrate Concentration (S):

kg/m³

Average Daily Influent Flow Rate (Qₐ):

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1. What is Average Daily Influent Flow Rate?

Average Daily Influent Flow Rate is the total discharge that comes in the reactor. It represents the volume of wastewater entering a treatment system per unit time, typically measured in cubic meters per second.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Q_a = \frac{(O_2 + (1.42 \times P_x)) \times f}{8.34 \times (S_o - S)} \]

Where:

\( Q_a \) — Average Daily Influent Flow Rate (m³/s)
\( O_2 \) — Theoretical Oxygen Requirement (kg/s)
\( P_x \) — Net Waste Activated Sludge (kg/s)
\( f \) — BOD Conversion Factor
\( S_o \) — Influent Substrate Concentration (kg/m³)
\( S \) — Effluent Substrate Concentration (kg/m³)

Explanation: This formula calculates the average daily flow rate based on oxygen requirements, sludge production, BOD conversion, and substrate concentration differences.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculation is crucial for designing wastewater treatment systems, determining reactor sizing, optimizing treatment processes, and ensuring regulatory compliance for effluent quality.

4. Using the Calculator

Tips: Enter all values in the specified units. Ensure that Influent Substrate Concentration is greater than Effluent Substrate Concentration. All values must be positive numbers.

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 the volatile suspended solids, accounting for the oxygen demand of biomass.

Q2: Why is the 8.34 constant used?
A: The 8.34 constant is used to convert between different units (mg/L to kg/m³) and ensure dimensional consistency in the calculation.

Q3: What is a typical range for BOD Conversion Factor?
A: The BOD Conversion Factor typically ranges from 0.6 to 0.8, representing the fraction of ultimate BOD that is measured in the 5-day BOD test.

Q4: How does this calculation help in treatment plant design?
A: This calculation helps determine the required treatment capacity, aeration system sizing, and overall plant design based on oxygen demand and substrate removal requirements.

Q5: What are common units for substrate concentration?
A: Substrate concentration is typically measured in mg/L or kg/m³, with 1 mg/L = 0.001 kg/m³.