Which parameter is used to evaluate the settleability of sludge?

Which parameter is used to evaluate the settleability of sludge?

• A. DO
• B. SVI
• C. MLSS
• D. pH

Answer: (B)

The concept being tested is how to quantify how well sludge settles in a clarifier. The parameter used to evaluate settleability is the Sludge Volume Index. It captures both how much settled sludge is produced in a standard 30-minute settle test and how dense that sludge is, by relating the settled volume (in mL) to the solids concentration (MLSS, g/L). A lower SVI means sludge settles readily, while a high SVI indicates poor settleability, often due to bulking from filamentous bacteria. DO, MLSS, and pH don’t directly measure how fast or effectively sludge settles. DO relates to oxygen content in the mixed liquor, MLSS is about how much solids are present, and pH shows acidity/alkalinity. Each can influence treatment performance, but none directly quantify settleability like SVI does.

The concept being tested is how to quantify how well sludge settles in a clarifier. The parameter used to evaluate settleability is the Sludge Volume Index. It captures both how much settled sludge is produced in a standard 30-minute settle test and how dense that sludge is, by relating the settled volume (in mL) to the solids concentration (MLSS, g/L). A lower SVI means sludge settles readily, while a high SVI indicates poor settleability, often due to bulking from filamentous bacteria.

DO, MLSS, and pH don’t directly measure how fast or effectively sludge settles. DO relates to oxygen content in the mixed liquor, MLSS is about how much solids are present, and pH shows acidity/alkalinity. Each can influence treatment performance, but none directly quantify settleability like SVI does.