1. What is Sludge Volume Index?

Sludge Volume Index (SVI) is the volume occupied by 1 gram of activated sludge after 30 minutes of settling in a 1-liter graduated cylinder. SVI is expressed in milliliters per gram and is a key parameter in wastewater treatment processes.

2. How Does the Calculator Work?

The calculator uses the SVI formula:

Where:

• \( SVI \) — Sludge Volume Index (mL/g)
• \( V_{ob} \) — Sludge Volume (mL/L)
• \( X \) — Mixed Liquor Suspended Solids (MLSS) (mg/L)

Explanation: The formula calculates the volume occupied by settled sludge per unit mass, providing insight into sludge settling characteristics.

3. Importance of SVI Calculation

Details: SVI is crucial for assessing the settleability of activated sludge in wastewater treatment plants. It helps in monitoring plant performance and making operational adjustments.

4. Using the Calculator

Tips: Enter sludge volume in mL/L and MLSS in mg/L. Both values must be positive numbers for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is a good SVI value?
A: Typically, SVI values between 50-150 mL/g indicate good settling sludge. Values above 150 may indicate bulking sludge.

Q2: How is sludge volume measured?
A: Sludge volume is measured after 30 minutes of settling in a 1-liter graduated cylinder.

Q3: What factors affect SVI?
A: Factors include sludge age, food-to-microorganism ratio, temperature, and presence of filamentous organisms.

Q4: How often should SVI be measured?
A: Daily monitoring is recommended for wastewater treatment plants to ensure optimal operation.

Q5: What does a high SVI indicate?
A: High SVI values (>150 mL/g) often indicate poor sludge settling characteristics, which may lead to clarifier problems.