SVI is a measure of
The SVI is the volume, in milliliters, occupied by 1 gram of settled activated sludge, and it is a measure of the settling characteristics of the sludge. The SVI is easily calculated as shown in Equation 7. Equation 7: Sludge Volume Index Formula. Any wastewater textbook will provide a “recommended range” for the SVI. Sludge Volume Index (SVI) is a very important indicator that determines your control or rate of desludging on how much sludge is to be returned to the aeration basin and how much to take it out from the system. The SVI is the volume, in milliliters, occupied by 1 gram of settled activated sludge, and it is a measure of the settling characteristics of the sludge. The SVI is easily calculated as shown in Equation 7. Equation 7: Sludge Volume Index Formula. Sludge Volume Index. Some discussion of the sludge volume index is warranted. Of all the process control formulas discussed in so far, the SVI is the easiest and quickest for operators to perform. And it only requires a one liter graduated beaker or settleometer. Of all the process control formulas discussed in so far, the SVI is the easiest and quickest for operators to perform. And it only requires a one liter graduated beaker or settleometer. Some wastewater plants use a 1000 mL graduated cylinder, the use of which is discouraged. The SVI is the volume, in milliliters, occupied by 1 gram of settled activated sludge, and it is a measure of the settling characteristics of the sludge. Sludge Volume Index is a valuable measure of sludge settleability characteristics and can be monitored to help prevent process problems. Sludge Volume Index (SVI) is an extremely useful parameter tomeasure in a wastewater treatment process. In simple terms, SVI is the result of a mathematical calculation. The sludge volume index (SVI), introduced by Mohlman in 1934, has become the standard measure of the physical characteristics of activated sludge solids. It is defined as the volume in ml occupied by 1 g activated sludge after settling the aerated liquor for 30 min (Dick and Vesilind, 1969). Analytics. Some general SVI guidelines are given below: SVI = 80 mL/g or less. An SVI of 80 or less usually indicates a sludge that is dense and has rapid settling characteristics. SVI = 100 to 200 mL/g. Most activated sludge plants seem to produce a clear, high-quality effluent with an SVI in the range of 100 to 200. The SVI should be determined when the facility is running at optimum, and should be used as a benchmark. Testing for SVI. The standard SVI test requires a 1-liter graduated cylinder for the MLSS settling test. A separate aliquot of mixed liquor is used for a total suspended solids (TSS) test.
The settling characteristics of the sludge.