Rheology and drying characteristics of sludge in the region of Liege

Abstract

This study delves into the drying behavior and rheological properties of sludge in the Liege region, focusing on characterising essential parameters to contribute to the optimization of sludge management by understanding the influencing characteristics and properties. A series of experiments is conducted on sludge samples from wastewater treatment plants to explicate the diversity of sewage sludge in the Liege region, covering the possible factors that can alter sludge drying, and rheology such as origins, history of treatment, mechanical traits, and others. Five wastewater treatment stations in Liege were covered, each utilizing similar or different treatment and mechanical methods. Experiments cover dry matter content determination, volatile matter content analysis, convective micro-drying, convective macro-drying, texture profile analysis (TPA), penetrometry, volume and area change during drying, and amplitude sweep. The study contributes valuable insights into sludge behavior during drying and highlights parameters critical for effective sludge management. By characterizing properties such as adhesiveness, cohesiveness, hardness, viscoelastic and rheological behavior, relate them to the drying performance illustrated by the drying flux, duration and moisture content change. This research provides a contribution for a better future, adding knowledge to a field that still have rooms for optimization. The findings may empower wastewater treatment facilities to make decisions regarding sludge handling by presenting the impact of rheological and texture properties on the drying behavior, aiming to enhance operational efficiency, reduce environmental impacts, and align with sustainable waste management practices.