Volume Of Wasted Sludge Per Day Given Oxygen Required In Aeration Tank Calculator

Formula Used:

\[ V_w = \frac{\left(\frac{Q_s \times (Q_i - Q)}{f} - O_2\right)}{1.42 \times X} \]

Sewage Discharge (Qs):

m³/s

Influent BOD (Qi):

kg/m³

Effluent BOD (Q):

kg/m³

Ratio of BOD to Ultimate BOD (f):

Theoretical Oxygen Requirement (O2):

kg/s

MLSS (X):

kg/m³

Volume of Wasted Sludge (Vw):

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1. What is Volume of Wasted Sludge?

Volume of Wasted Sludge is the amount of sludge that is removed or wasted from a wastewater treatment process on a daily basis. It is a critical parameter in maintaining the proper balance of microorganisms in the aeration tank and ensuring efficient treatment process.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ V_w = \frac{\left(\frac{Q_s \times (Q_i - Q)}{f} - O_2\right)}{1.42 \times X} \]

Where:

\( V_w \) — Volume of wasted sludge (m³/s)
\( Q_s \) — Sewage discharge (m³/s)
\( Q_i \) — Influent BOD (kg/m³)
\( Q \) — Effluent BOD (kg/m³)
\( f \) — Ratio of BOD to ultimate BOD
\( O_2 \) — Theoretical oxygen requirement (kg/s)
\( X \) — MLSS (kg/m³)

Explanation: This formula calculates the volume of sludge that needs to be wasted daily to maintain the proper food-to-microorganism ratio and oxygen balance in the aeration tank.

3. Importance of Volume of Wasted Sludge Calculation

Details: Proper sludge wasting is essential for maintaining treatment efficiency, controlling sludge age, preventing sludge bulking, and ensuring compliance with effluent quality standards.

4. Using the Calculator

Tips: Enter all values in appropriate units. Sewage discharge in m³/s, BOD values in kg/m³, ratio as dimensionless, oxygen requirement in kg/s, and MLSS in kg/m³. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: Why is sludge wasting necessary in wastewater treatment?
A: Sludge wasting is necessary to maintain the proper balance of microorganisms, control sludge age, and prevent accumulation of inert materials in the system.

Q2: What happens if too much sludge is wasted?
A: Excessive sludge wasting can reduce treatment efficiency as there won't be enough microorganisms to treat the incoming wastewater.

Q3: What happens if too little sludge is wasted?
A: Insufficient sludge wasting can lead to sludge bulking, poor settling characteristics, and reduced treatment efficiency.

Q4: How often should sludge be wasted?
A: Sludge wasting is typically done continuously or daily, depending on the plant size and operational requirements.

Q5: What is the significance of the 1.42 factor in the formula?
A: The 1.42 factor represents the oxygen equivalent of the volatile suspended solids, accounting for the oxygen demand of the biomass.