What does the high sludge volume index indicate in activated sludge process?
That’s what SVI helps describe. An SVI of 80 or less usually indicates a sludge that is dense and has rapid settling characteristics. Most activated sludge plants seem to produce a clear, high-quality effluent with an SVI in the range of 100 to 200.
How is the sludge volume index calculated?
Sludge Volume Index, also known as SVI, describes how well the sludge from the aeration tank settles and compacts. It simply determines the suspended solids concentration of the sample from the aeration tank, in mg/L. Sludge volume index ( SVI ) is calculated by dividing the settleability by the MLSS concentration.
What is FM ratio in activated sludge process?
The F/M ratio is a process control number that helps you to determine the proper number of microorganisms for your system. To do this calculation, you will need the following information: Influent Flow into your activated sludge system (Flow MGD) Influent CBOD (mg/l) concentration into your aeration tank.
How do you calculate SVI and SDI?
A calculation used to indicate the settleability of sludge in a secondary clarifier or effluent that is related to the calculation for sludge volume index (SVI). The weight in grams of 100 milliliters of sludge after settling for 30 minutes. SDI = 100/SVI.
Why is SVI important?
SVI gives a more accurate picture of the sludge settling characteristics than settleability or MLSS alone. Sludge Volume Index (SVI) is an extremely useful parameter to measure in a wastewater treatment process. SVI used to indicate the physical state of sludge produced in a biological aeration system.
What is meant by sludge volume index?
Sludge Volume Index (SVI) is used to describe the settling characteristics of sludge in the aeration tank in Activated Sludge Process. It is defined as ‘the volume (in mL) occupied by 1 gram of activated sludge after settling the aerated liquid for 30 minutes’.
What does sludge volume index indicate?
What is ideal f M ratio?
The optimal range for the F:M ratio in a complete mix system is 0.2 to 0.6 lb BOD/lb MLVSS (kg BOD/kg MLVSS).
What is low F M ratio?
Having a low F:M ratio, means you have too many bacteria in your wastewater system relative to the incoming Biochemical Oxygen Demand (BOD). This causes starvation of healthy floc forming bacteria, and issues such as bulking, or high effluent Total Suspended Solids (TSS).
What is a good SVI?
SVI = 100 to 200 mL/g. Most activated sludge plants seem to produce a clear, good-quality effluent with an SVI in this range. SVI = 250 mL/g or higher. At this elevated SVI, the sludge settles very slowly and compacts poorly in the settleability test.