Sludge Level Sensors and Transmitters

Sludge Level Sensors and Transmitters

Sludge level sensors and transmitters measure sludge blanket and separation zone behavior in sedimentation tanks to support efficient solids handling. The objective is straightforward: pump sludge, not water. Continuous monitoring of separation and transition zones during clarification and settling helps maintain stable operation and improves control of sludge withdrawal and downstream solids processing. Typical installations include primary and secondary clarifiers in wastewater treatment.

Endress+Hauser positions these instruments for applications where fouling, clogging, and mechanical interference can undermine measurement stability. Selection guidance differentiates between sensors with wipers for locations prone to fouling (clarifiers, sludge tanks, thickeners) and standard detectors for secondary clarifiers with surface skimmers or clear-water sedimentation tanks. This selection logic aligns instrument design to site-specific mechanical realities rather than relying on a single universal detector.

The measurement principle described is ultrasonic. A piezoelectric crystal generates a sonar signal, ultrasonic waves scan the separation zones, and the measured variable is the time required for the emitted signal to reach solids in the separation zone and return to the receiver. This time-of-flight approach is well proven for long-term stable sludge level measurement when installation and interference management are handled correctly.

Benefits include stable and reliable values by eliminating interferences such as floating sludge, gas bubbles, or moving skimmers, along with configuration flexibility via wiper/no-wiper options for different basins and solids regimes. Commissioning can be simplified through predefined calculation models, and mounting hardware supports implementation across clarifier geometries. These factors reduce tuning effort and improve confidence in the sludge blanket signal used for operational decisions.

From a system standpoint, sludge level measurement often becomes more valuable when paired with complementary sensors (for example, turbidity/solids, oxygen, pH) to correlate blanket movement with loading and biological performance. Liquiline multichannel/multiparameter devices can consolidate multiple sensors on a single transmitter, supporting coherent diagnostics and a unified signal interface to the control system.

At Eastern Controls, We are proud to be the exclusive authorized sales and service representative for Endress+Hauser.