# Determination of Sludge Volume Index

**Topics:**Water, Calcium carbonate, Total suspended solids

**Pages:**3 (421 words)

**Published:**October 10, 2013

Date: 29/07/2013

1. DETERMINATION OF SLUDGE VOLUME INDEX

1.1 . Aim:-

To determine the sludge volume index (SVI) of a given sample. 1.2 . Apparatus Required:-

Settling column – use 1 L graduated cylinder equipped with a stirring mechanism not more than 4 rpm. Stop watch, Filter paper, Hot Air oven, Pipette, 50 mL, Graduated Cylinder, Desiccators (Optional).

1.3 . Chemicals Required:-

5 grams of Calcium Carbonate (CaCO3)

1.4 . Formula Required:-

Sludge volume index = Settled sludge volume x 1000

Suspended solids

Total Suspended (in mg/L) = (A-B) x 1000

Sample Volume

Where, A = Weight of filter + dry residue (mg)

B = Weight of filter (mg)

1.5 . Theory:-

Sludge volume index (SVI) is the volume in millilitres occupied by 1 g of a suspension after 30 min settling. It is a calculation that indicates the tendency of activated sludge solids (aerated solids) to thicken or to become concentrated during the sedimentation/thickening process.

Sludge volume index (SVI) is an important indicator in the measurement the rate of desludging. It determines the quantity of sludge to be returned to the aeration basin and the quantity to be taken out from the system. Thus it serves as an important empirical measurement that can be used to maintain sufficient quantity of activated sludge in the aeration basin.

1.6.Procedure:-

1.6.1. Calculation of settled sludge volume

Weigh 5 gram of CaCO3 and transfer it into a 1 L graduated cylinder and make the solution up to the mark. Stir the solution till it is uniform and allow it to settle for 30 minutes. After the time period, read the marking corresponding to the height of settled sludge to determine the volume occupied by settled sludge. This reading is expressed in terms of mL/L and is reported as settled sludge (SV) value. .

1.6.2Calculation of total suspended solids

A sample...

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