What does the acronym SVI stand for in wastewater treatment?

The acronym SVI stands for Sludge Volume Index. This term is crucial in wastewater treatment as it measures the settleability of the sludge in a wastewater treatment process. The SVI is calculated by dividing the volume of settled sludge by the concentration of the solids in the mixed liquor, typically expressed in milliliters per gram.

A low SVI value indicates that the sludge has good settleability, which is essential for effective sedimentation in secondary clarifiers. Conversely, a high SVI can suggest that the sludge is poor in settleability, possibly leading to issues such as sludge washout and decreased treatment efficiency. Understanding and monitoring SVI helps operators optimize the biological treatment process, ensuring that the system operates smoothly and remains compliant with effluent discharge standards.

The other options, while they may appear to be related terms, do not accurately represent the standard term used in the context of wastewater treatment.