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Permittivity of Waste-Activated Sludge by an Open-Ended Coaxial Line

By Jake S. Bobowski, Thomas Johnson, and Cigdem Eskicioglu
Progress In Electromagnetics Research Letters, Vol. 29, 139-149, 2012


The complex permittivity of thickened waste activated sludge (WAS) was measured from 3 MHz to 40 GHz. The solid content of the thickened WAS sample was varied from 4.5% to 18% by weight. The permittivity spectra exhibit features typical of biological tissues that have a high water content. At high frequencies, a Debye type dispersion is observed with a relaxation rate of 19 GHz characteristic of the bulk water in the sample (γ-dispersion). At lower frequencies, the solid content of the samples determines the properties of the permittivity. The onset of the so-called β-dispersion, attributed to the charging of cell membranes, occurs between 10-100 MHz. For samples with higher solid concentrations, a weak dispersion of the real part of the permittivity, characteristic of bound water, was observed at intermediate frequencies (δ-dispersion).


Jake S. Bobowski, Thomas Johnson, and Cigdem Eskicioglu, "Permittivity of Waste-Activated Sludge by an Open-Ended Coaxial Line," Progress In Electromagnetics Research Letters, Vol. 29, 139-149, 2012.


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