Influent BOD given Specific Substrate Utilization Rate Per Day Calculator

Formula Used:

\[ Q_i' = \frac{U \times V \times X'}{Q_s} + Q_o \]

Specific Substrate Utilization Rate (U):

per day

Volume of Tank (V):

m³

Mixed Liquor Suspended Solids (X'):

kg/m³

Sewage Discharge (Qₛ):

m³/day

Effluent BOD (Qₒ):

kg/m³

Influent BOD (Qᵢ'): kg/m³

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1. What is Influent BOD given Specific Substrate Utilization Rate?

Definition: This calculator determines the influent Biochemical Oxygen Demand (BOD) based on the rate at which microorganisms consume organic matter in a wastewater treatment system.

Purpose: It helps wastewater treatment professionals estimate the organic load entering a treatment system based on substrate utilization parameters.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Q_i' = \frac{U \times V \times X'}{Q_s} + Q_o \]

Where:

\( Q_i' \) — Influent BOD (kg/m³)
\( U \) — Specific substrate utilization rate (per day)
\( V \) — Volume of tank (m³)
\( X' \) — Mixed liquor suspended solids (kg/m³)
\( Q_s \) — Sewage discharge (m³/day)
\( Q_o \) — Effluent BOD (kg/m³)

Explanation: The formula calculates the organic load entering the system based on microbial consumption rates and system parameters.

3. Importance of Influent BOD Calculation

Details: Accurate influent BOD estimation is crucial for designing and operating wastewater treatment plants, ensuring proper treatment capacity and efficiency.

4. Using the Calculator

Tips: Enter the specific substrate utilization rate, tank volume, MLSS concentration, sewage discharge rate, and effluent BOD. All values must be > 0 (except effluent BOD which can be 0).

5. Frequently Asked Questions (FAQ)

Q1: What is typical specific substrate utilization rate?
A: Rates typically range from 0.1 to 1.0 per day depending on wastewater characteristics and microbial population.

Q2: How do I determine mixed liquor suspended solids?
A: MLSS is measured through laboratory analysis of samples from the aeration tank.

Q3: Why include effluent BOD in the calculation?
A: Effluent BOD accounts for the organic matter that remains untreated in the system.

Q4: What units should I use for sewage discharge?
A: Use consistent units (m³/day) for all volume/time measurements in the calculation.

Q5: How accurate is this calculation?
A: It provides a theoretical estimate; actual values may vary based on system conditions and wastewater characteristics.