Mass of Wasted Activated Sludge Calculator

Mass of Wasted Activated Sludge Formula:

\[ M_{ws} = (Y \times Q_s \times (Q_i - Q_o)) - (K_e \times V \times X') \]

Maximum Yield Coefficient (Y):

Sewage Discharge (Q_s):

m³/s

Influent BOD (Q_i):

kg/m³

Effluent BOD (Q_o):

kg/m³

Endogenous Respiration Rate Constant (K_e):

1/s

Volume of Tank (V):

m³

Mixed Liquor Suspended Solids (X'):

kg/m³

Mass of Wasted Activated Sludge (kg):

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1. What is Mass of Wasted Activated Sludge?

Definition: This is the total mass of sludge that is removed from the wastewater treatment process, specifically from the activated sludge system.

Purpose: It helps wastewater treatment professionals determine how much sludge needs to be removed from the system to maintain optimal treatment conditions.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ M_{ws} = (Y \times Q_s \times (Q_i - Q_o)) - (K_e \times V \times X') \]

Where:

\( M_{ws} \) — Mass of wasted activated sludge (kg)
\( Y \) — Maximum yield coefficient
\( Q_s \) — Sewage discharge (m³/s)
\( Q_i \) — Influent BOD (kg/m³)
\( Q_o \) — Effluent BOD (kg/m³)
\( K_e \) — Endogenous respiration rate constant (1/s)
\( V \) — Volume of tank (m³)
\( X' \) — Mixed liquor suspended solids (kg/m³)

Explanation: The formula calculates the difference between the mass of biomass produced and the mass of biomass lost through endogenous respiration.

3. Importance of Mass of Wasted Activated Sludge Calculation

Details: Proper sludge wasting is crucial for maintaining the right balance of microorganisms in the activated sludge process, ensuring efficient wastewater treatment.

4. Using the Calculator

Tips: Enter all required parameters with appropriate units. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for Maximum Yield Coefficient (Y)?
A: Typically ranges from 0.4 to 0.8 mg biomass/mg substrate for domestic wastewater.

Q2: How do I determine the Endogenous Respiration Rate Constant?
A: It's typically determined experimentally and ranges from 0.04 to 0.10 per day (≈4.63×10⁻⁷ to 1.16×10⁻⁶ per second).

Q3: What does a negative result mean?
A: A negative result suggests calculation error or unrealistic input values, as mass cannot be negative.

Q4: How often should sludge be wasted?
A: Typically daily, but depends on system design and loading conditions.

Q5: What affects Mixed Liquor Suspended Solids concentration?
A: Influent characteristics, aeration, sludge age, and temperature all affect MLSS.