
Activated Sludge
Mixed Liquor Suspended Solids (MLSS) represent the concentration of suspended solids in the aeration tank during the activated sludge process. Monitoring MLSS provides valuable insight into the amount of active biomass available to break down organic pollutants in real time.
Return Activated Sludge (RAS) monitoring helps control the volume of biomass being recirculated back into the aeration tank, ensuring stable and efficient treatment performance.
Olpas sensors have an exceptional fouling resistance, resulting in low maintenance needs while resisting drift.

Olpas Sensor are available as both submersible sensors and sensors for inline mounting.
Key features
Colour changes (or other optical variations) of the sludge or the water have no impact on of the measurement reliability
Less drift, compared to traditional optical sensors (even with a longer maintenance intervals)
Extensive fouling resistance, even in challenging circumstances where optical sensors would need frequent maintenance
Broad range of particle sizes (from nanometers to millimeters)
Broad range of concentrations
Other measurements available
Next to the MLSS-sensor and the RAS-sensor, Olpas also has sludge concentration sensors, and sensors to measure TSS.
Available Products
Number of selected Products:
2