Performance index of activated sludge in sewage treatment equipment

- May 06, 2019-

In sewage treatment equipment, there are two kinds of performance indexes of activated sludge method, one is to show the index by the settlement performance of activated sludge, and the other is to show the index by the amount of activated sludge microorganism in the mixed liquid.

Sewage treatment Equipment

1, sewage treatment equipment, the settlement performance of activated sludge indicators:

The settlement Performance index of activated sludge is mainly two display modes, one is sludge settlement ratio (SV) and the other is Sludge Volume index (SVI). Sludge settlement ratio (SV), also known as 30min precipitation rate.

Refers to the volume ratio of precipitated sludge and the original mixture formed by the mixing liquid after static 30min in cylinder, expressed in%.

2. Microbial quantity index of activated sludge in mixed liquid of sewage treatment equipment:

There are two main manifestations of microbial quantity index in activated sludge mixture, one is the concentration of suspended solids in mixed liquid (MLSS) and the other is the concentration of volatile suspended solids (MLVSS) in mixed liquid. Simply put, MLSS refers to the concentration of mixed liquid sludge, which indicates the total weight of the activated sludge solids contained in the mixed liquid of the unit volume of the aeration tank, MLSS is used to represent some errors in the microbial quantity of activated sludge.

But MLSS is easy to measure, so it is more commonly used. MLVSS refers to the concentration of organic solids in mixed liquid activated sludge, MLVSS can more accurately represent the number of microorganisms.

MLSS and MLVSS are the relative indexes of microbial quantity in activated sludge, MLVSS/MLSS are fixed under certain conditions, and for domestic sewage, the value is about 0.75.

This is in our actual equipment debugging and utilization is more common, but also a simple reaction of the sludge growth state of a value, the general selection of 1000ML cylinder to measure more accurate point, by judging the settlement speed, settlement ratio, sludge status and so on to faster and better to the activated sludge culture success.

Sewage treatment Equipment Sludge settlement ratio (SV) can basically reflect the normal operation of the aeration tank of activated sludge, can be used to control and adjust the discharge of residual sludge, but also through it to detect sludge expansion and other abnormal phenomena in a timely manner.

The treatment of domestic sewage generally controls the SV between the 20%~30%. Sludge volume index (SVI), simply known as Sludge Index.

Refers to the volume of precipitated sludge formed by 1g dry sludge at the outlet of the aeration tank after 30min of static sinking, in mL. Compared with SV, SVI better reflects the sedimentation performance of sludge, its value is too low, which indicates that the inorganic components of activated sludge are many and the mud grains are small and dense. Too high also indicates that the sludge settlement performance is not good. The SVI value of domestic sewage treatment is between 50~150.