【Weekly Topic】- A decrease in the sludge volume index can render the sludge inactive
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SVI: Sludge Volume Index, which is an indicator used to measure the settling performance of activated sludge. It refers to the volume occupied by 1 g of dry sludge after the aeration tank mixture has been left to settle for 30 minutes, expressed in mL. In other words, SVI = volume of sludge after 30 minutes of settling (mL) / dry weight of sludge (g); thus, SVI = SV30/MLSS. The SVI value can effectively reflect the looseness of the activated sludge and its flocculation and sedimentation properties. A good activated sludge SVI is usually between 50 and 120. Does a decrease in the sludge volume index cause the sludge to lose its activity?
A decrease in the sludge volume index can cause the sludge to lose its activity. During operation, although it is less important than the previous issue, it still requires sufficient attention. The reasons for sludge compaction and reduced activity include a sudden increase in inorganic suspended solids in the influent water ； Environmental conditions deteriorate, reducing the conversion rate of organic matter ； The concentration of organic matter decreases. The reasons for the reduction in sludge include: a decrease in organic nutrients ； Excessive aeration time ； The reflux ratio is low while the amount of excess sludge discharged is high ； Sludge floats to the surface, leading to sludge loss and other issues. Methods to solve the above problems include: adding nutrients ； Reduce aeration time or decrease the amount of aeration, as well as adjust the recirculation ratio and sludge discharge volume ； Prevents sludge from floating and improves sedimentation efficiency.
Does a decrease in the sludge volume index cause the sludge to lose its activity? Yes
A decrease in the sludge volume index can render the sludge inactive. Reasons for the reduced activity of the sludge include a sudden increase in inorganic suspended solids in the influent water, deteriorating environmental conditions, a low rate of organic matter conversion, and a decrease in organic matter concentration. Reasons for a reduction in the amount of sludge include a lack of organic nutrients, long aeration times, a low recirculation ratio resulting in high amounts of excess sludge being discharged, and sludge floating to the surface and thus being lost. Methods to solve the above problems include: adding nutrients ； Reduce aeration time or decrease the amount of aeration, as well as adjust the recirculation ratio and sludge discharge volume ； Prevents sludge from floating and improves sedimentation efficiency.
This post was last edited by CoCo070563 on 2015-8-24 at 18:07. A low sludge volume index indicates that inorganic substances make up a large proportion of the sludge; when there is a high amount of inorganic substances, it naturally affects the activity of the sludge.