Volume of Reactor given Wasting Rate from Return Line Calculator

Reactor Volume Formula:

\[ V = \theta_c \times \frac{(Q_w' \times X_r) + (Q_e \times X_e)}{X} \]

Mean Cell Residence Time:

seconds

WAS Pumping Rate from Return Line:

m³/s

Sludge Concentration in Return Line:

kg/m³

Effluent Flow Rate:

m³/s

Solid Concentration in Effluent:

kg/m³

MLSS:

kg/m³

Reactor Volume (m³):

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1. What is Volume of Reactor given Wasting Rate from Return Line?

Definition: This calculator determines the required volume of a biological reactor in wastewater treatment based on the wasting rate from the return line and other operational parameters.

Purpose: It helps wastewater treatment plant operators and engineers design and optimize activated sludge systems.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ V = \theta_c \times \frac{(Q_w' \times X_r) + (Q_e \times X_e)}{X} \]

Where:

\( V \) — Reactor Volume (cubic meters)
\( \theta_c \) — Mean Cell Residence Time (seconds)
\( Q_w' \) — WAS Pumping Rate from Return Line (m³/s)
\( X_r \) — Sludge Concentration in Return Line (kg/m³)
\( Q_e \) — Effluent Flow Rate (m³/s)
\( X_e \) — Solid Concentration in Effluent (kg/m³)
\( X \) — Mixed Liquor Suspended Solids (MLSS) (kg/m³)

Explanation: The formula calculates the reactor volume needed to maintain the desired sludge age while accounting for solids wasted through both the return line and effluent.

3. Importance of Reactor Volume Calculation

Details: Proper reactor sizing ensures effective biological treatment, meets effluent quality standards, and maintains stable operation of the activated sludge process.

4. Using the Calculator

Tips: Enter all required parameters with appropriate units. Mean Cell Residence Time and MLSS must be positive values. Other parameters can be zero if not applicable.

5. Frequently Asked Questions (FAQ)

Q1: What is Mean Cell Residence Time (θc)?
A: Also called sludge age, it's the average time microorganisms spend in the system, typically 5-15 days for conventional activated sludge.

Q2: How do I determine MLSS concentration?
A: MLSS is measured through laboratory analysis of mixed liquor samples, typically ranging from 1500-4000 mg/L (1.5-4 kg/m³).

Q3: What if I don't have a return line wasting rate?
A: If wasting only occurs through the effluent, set Qw to zero and the calculation will use only effluent solids loss.

Q4: Why is reactor volume important?
A: Proper volume ensures sufficient contact time between microorganisms and wastewater for effective treatment.

Q5: How does this relate to F/M ratio?
A: Reactor volume affects Food-to-Microorganism ratio, a key parameter for process control in activated sludge systems.