Microwave Transmission Measurement

Microwave Transmission Measurement

Microwave transmission measurement is an inline technique used to determine concentration - especially total solids - directly in the process stream. The method is positioned as a real-time, maintenance-free approach for continuous inline measurement of total solids, providing a control variable where traditional sampling and laboratory determination are too slow for effective feedback. The result is faster response to process changes and more stable control of solids-handling operations.

In typical implementations, a microwave signal is transmitted through the flowing medium and analyzed based on how the process material attenuates or shifts the signal. These changes correlate with concentration and composition, enabling a continuous measurement without consumable reagents. The offering is presented as a sensor-with-transmitter solution (Teqwave M family), supporting standard outputs and industrial communications for direct integration into control platforms and historian environments.

Benefits focus on operational stability and reduced maintenance burden. Continuous solids measurement improves control of thickening, dilution, and dewatering feed, and supports more consistent downstream performance. The “maintenance-free” positioning is particularly relevant in services where optical windows foul quickly or where sampling is impractical due to solids content. With reliable real-time measurement, chemical conditioning and energy inputs can be tuned more tightly, improving performance while reducing variability.

Typical applications include sludge handling in water and wastewater treatment, where solids concentration drives polymer demand, centrifuge or belt press loading, and thickener performance. Continuous solids trending also supports digester feed consistency, return activated sludge control, and optimization of recirculation rates in high-solids loops. Beyond municipal treatment, the same measurement concept applies to other slurry services where solids concentration must be stabilized for product quality or equipment protection.

Implementation considerations include selecting an installation location that provides representative mixing, avoiding gas entrainment where possible, and establishing a correlation strategy against laboratory reference methods during commissioning. Pipe size, temperature influence, and material conductivity can affect calibration and should be considered early. Integration commonly uses analog and digital interfaces (e.g., 4–20 mA, HART, Modbus, Ethernet) to support closed-loop control and diagnostics.

Field Instruments & Controls, Inc. an exclusive authorized representative of sales and service for Endress+Hauser.