Sludge Level Sensors and Transmitters

Sludge Level Sensors and Transmitters

Sludge level (sludge blanket) sensors continuously measure the interface and transition zones within sedimentation tanks to determine where solids accumulate relative to clarified water. These systems are widely used in primary and secondary clarification to improve solids handling efficiency and stabilize downstream processes.

Accurate sludge blanket measurement helps ensure sludge is removed intentionally - avoiding unnecessary pumping of clarified water and reducing hydraulic and solids loading variability. This improves clarification performance, reduces carryover risk, and supports more stable thickening and dewatering operations. The operational benefit is strongest where influent conditions fluctuate and where fouling or skimming behavior can mislead operators without a direct interface measurement.

Ultrasonic sludge level measurement uses a piezoelectric crystal to emit a sonar signal and evaluates the time required for the ultrasonic pulse to reach solid particles in the separation zone and return to the receiver. This time-of-flight approach is well established and supports long-term stable measurement. Sensor variants with and without a wiper allow adaptation to fouling and clogging risk in clarifiers, sludge tanks, and thickeners.

Typical applications include primary and secondary clarifiers in wastewater treatment, sludge holding tanks, gravity thickeners, and other settling processes in industries such as chemicals and mining. Measurement is used to optimize sludge withdrawal rate, maintain desired blanket depth, and reduce process variability that can degrade effluent quality or increase dewatering costs.

Engineering focus areas include mounting hardware appropriate to basin geometry, interference mitigation (floating sludge, gas bubbles, skimmers), and commissioning using predefined calculation models where available. Consolidated transmitter architectures can support sludge level alongside other liquid-analysis parameters on a single platform, improving correlation and simplifying lifecycle support for multi-sensor basins.

George E. Booth Co., an exclusive authorized representative of sales and service for Endress+Hauser.