On the rheological characteristics of sewage sludge

• Main Authors: Tomáš Vítěz, Libor Severa
• Format: Article
• Language: English
• Published: Mendel University Press 2010-01-01
• Series: Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis
• Subjects: sewage sludge; apparent viscosity; modeling
• Online Access: https://acta.mendelu.cz/58/2/0287/

The work is focused on characterization of rheological behavior of sewage sludges sampled at different stages of waste water treatment. The main attention was focused on dynamic viscosity dependence on temperature, and shear rate. The sludge samples were examined under temperature ranging from 1 °C to 25 °C and under shear rate ranging from 0.34 s−1 to 68 s−1. Rotary digital viscometer (concentric cylinders geometry) was used to perform the reological measurements. The solids content of the sludge samples ranged from 0.43 % to 21.45 % (A and C samples, respectively) and ash free dry mass from 56.21 % to 67.80 % (A and B samples, respectively). The tested materials were found to be of non–Newtoninan nature and temperature dependent. Measured data were successfully cha­ra­cte­ri­zed by several mathematical models (Arrhenius, Bingham Plastic, Casson Law, Exponential, Gaussian, and IPC Paste) in MATLAB® software with satisfying correlations between experimental and computed results. The best match (R2 = 0.999) was received with use of Gaussian model, in both cases, shear rate and temperature dependence. The results are quite useful e.g. for the purpose of technological equipment design.