Mlss Returned Given Oxygen Demand Of Biomass Calculator

Formula Used:

\[ XR = \frac{\left(\frac{Q_s \times (Q_i - Q_b)}{f}\right) - O_2}{D_{O2} \times Q_w} \]

Sewage Discharge (Qs):

m³/s

Influent BOD (Qi):

kg/m³

Effluent BOD (Qb):

kg/m³

Ratio of BOD to Ultimate BOD (f):

Theoretical Oxygen Requirement (O2):

kg/s

Oxygen Demand of Biomass (DO2):

Volume of Wasted Sludge per day (Qw):

m³/s

MLSS in Returned or Wasted Sludge (XR):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is MLSS in Returned or Wasted Sludge?

MLSS in Returned or Wasted Sludge refers to the mixed liquor suspended solids concentration in the returned or wasted sludge from a wastewater treatment process. It represents the concentration of microbial biomass that is either recycled back to the aeration tank or removed from the system.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ XR = \frac{\left(\frac{Q_s \times (Q_i - Q_b)}{f}\right) - O_2}{D_{O2} \times Q_w} \]

Where:

\( Q_s \) — Sewage Discharge (m³/s)
\( Q_i \) — Influent BOD (kg/m³)
\( Q_b \) — Effluent BOD (kg/m³)
\( f \) — Ratio of BOD to Ultimate BOD
\( O_2 \) — Theoretical Oxygen Requirement (kg/s)
\( D_{O2} \) — Oxygen Demand of Biomass
\( Q_w \) — Volume of Wasted Sludge per day (m³/s)

Explanation: This formula calculates the concentration of mixed liquor suspended solids in returned or wasted sludge based on the oxygen demand and mass balance principles in wastewater treatment.

3. Importance of MLSS Calculation

Details: Accurate MLSS calculation is crucial for proper operation of activated sludge systems, maintaining appropriate biomass concentration, and ensuring efficient organic matter removal in wastewater treatment plants.

4. Using the Calculator

Tips: Enter all required parameters with appropriate units. Ensure values are positive and within reasonable ranges for wastewater treatment applications.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for MLSS in activated sludge systems?
A: MLSS typically ranges from 1500-4000 mg/L (1.5-4.0 kg/m³) in conventional activated sludge systems.

Q2: Why is MLSS important in wastewater treatment?
A: MLSS concentration affects treatment efficiency, oxygen demand, settling characteristics, and overall process stability.

Q3: How often should MLSS be monitored?
A: MLSS should be monitored daily in most wastewater treatment plants to maintain optimal process control.

Q4: What factors affect MLSS concentration?
A: Factors include wastewater flow rate, organic loading, sludge age, temperature, and sludge wasting rate.

Q5: How does MLSS relate to SVI?
A: MLSS and Sludge Volume Index (SVI) together help assess the settling characteristics and quality of activated sludge.