1. What is the SVI Equation?

The Sludge Volume Index (SVI) is a measurement used in wastewater treatment to evaluate the settling characteristics of sludge in the aeration tank. It indicates the volume occupied by 1 gram of activated sludge after 30 minutes of settling.

2. How Does the Calculator Work?

The calculator uses the SVI equation:

Where:

• \( Settled\ Volume \) — Volume of settled sludge in 30 minutes (mL/L)
• \( MLSS \) — Mixed Liquor Suspended Solids concentration (mg/L)

Explanation: The equation calculates the volume in milliliters occupied by 1 gram of sludge solids after 30 minutes of settling.

3. Importance of SVI Calculation

Details: SVI is crucial for wastewater treatment plant operation as it helps assess sludge settling characteristics, bulking potential, and overall treatment efficiency.

4. Using the Calculator

Tips: Enter settled volume in mL/L and MLSS in mg/L. Both values must be greater than 0 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 often should SVI be measured?
A: Daily monitoring is recommended for most wastewater treatment plants to track sludge settling characteristics.

Q3: What affects SVI values?
A: Factors include sludge age, food-to-microorganism ratio, dissolved oxygen levels, and wastewater characteristics.

Q4: What's the difference between SVI and DSVI?
A: DSVI (Diluted Sludge Volume Index) is measured at a standardized MLSS concentration (typically 1.5 g/L) for better comparison.

Q5: How is SVI used in billing?
A: Some wastewater treatment plants use SVI to assess treatment efficiency which may factor into billing calculations for industrial customers.