Analysis of rheological properties of modified sewage sludge

• Published in: Desalination and water treatment 2018-12, Vol.134, p.143-147
• Main Author: Wolski, Paweł
• Format: Article
• Language: English
• Subjects: Methane fermentation; Micropollutants; Rheological parameters; Sewage sludge; Ultrasonic field
• ISSN: 1944-3986
• DOI: 10.5004/dwt.2018.22765

Sewage sludge conditioning leads to the modification of its physical and chemical parameters. Determination of rheological models allows for a detailed identification of rheological properties. One- and multi-parameter models allow for the approximation of the flow curves, whereas determination of the values of yield limits for the modified sludge allows for the control of the processes of thickening, dewatering, and spreading of micropollutants contained in the sludge subjected to flow. The examinations were aimed to determine rheological parameters and rheological models of sewage sludge conditioned using physical methods before and after the process of anaerobic fermentation. Physical conditioning was conducted using the energy of the ultrasonic field emitted by means of ultrasound processor. The examinations revealed that the use of the conditioning factor for preparation of sewage sludge increases the value of shear stress, viscosity, and yield limits with respect to non-conditioned sludge. The conditioning process impacts on the value of yield stress, thus reducing the flow capability of the sludge. The fermentation process, which causes mineralization of organic compounds, has an effect on the reduction of the value of shear stress. Reduction in the value of rheological parameters is correlated with total decline in dry mass.