Microwave Transmission Measurement

Microwave Transmission Measurement

Microwave transmission measurement systems are inline instruments that determine total solids (TS) by measuring how microwaves propagate through a medium and converting that response into concentration-related quantities. In Endress+Hauser’s offering, this is positioned specifically for continuous total solids measurement in mixtures such as wastewater sludge, where conventional optical or mechanical approaches can be limited by fouling or matrix dependence.

The primary benefit is robust TS measurement that is independent of color and turbidity and engineered for low maintenance. Wastewater sludge treatment often relies on lab sampling for TS, but continuous inline measurement reduces delays, improves responsiveness, and supports tighter control of polymer dosing, digestion loading, thickening performance, and dewatering efficiency. The technology is presented as covering a broad TS range up to 50% TS and supporting control from primary clarification through dewatering.

The measurement principle leverages the interaction of electromagnetic waves with the molecular properties of the medium. By evaluating absorption and propagation speed, permittivity can be calculated; this correlates to total solids because water exhibits high permittivity relative to typical sludge solids, affecting time-of-flight and attenuation. Higher TS mixtures show measurably different microwave behavior than water-dominant mixtures, enabling concentration inference without optical dependence.

Implementation focuses on stable inline installation, reliable signal conversion, and integration into control architectures. Because the method is not driven by optical clarity, it is suited to harsh, variable sludge matrices where sensor cleaning burdens can dominate lifecycle cost. Instrument configuration and diagnostics are typically aligned with modern transmitter platforms to support signal conditioning, IO flexibility, and standardized maintenance practices.

Typical applications include wastewater treatment clarification, digestion monitoring, sludge thickening control, polymer dosing optimization, and dewatering performance management. It is also relevant in industries handling fibrous or particulate slurries - such as pulp & paper or selected food processes - where inline TS measurement improves consistency and resource efficiency.

Miller Mechanical Specialties, an exclusive authorized representative of sales and service for Endress+Hauser.