Geotechnical comparison of water treatment sludge and biomass ashes for soft soils' application: A greener approach analysis

1. Home
2. Publications
3. Online Library
4. Geotechnical comparison of water treatment sludge and biomass ashes for soft soils' application: A greener approach analysis

Water treatment sludge (WTS) and vegetal biomass ashes (VBA) are largely generated around the world and require sustainable management to minimize potential negative environmental impacts and risks for public health. Wastes bad management represents a risk for soils and waters contamination. Several international programs and goals have demanded the industries to introduce greener approaches to their processes. One of the sustainable alternatives for the management of those wastes is their valorization in the development of new materials for application in geotechnical works. Soft soils are known for having high volumetric variation and low resistance values, needing treatment or reinforcement. The researchs objective was to characterize an alum-sulphate coagulant-based WTS, pines-based VBA, two soft soils and four mixtures of each residue in different percentages (5%, 10%,15% and 20%) to evaluate the potential of WTS and VBA in chemical-mechanical properties. Therefore, particle size distribution, normal proctor compaction, specific gravity, plasticity indexes, permeability, oedometric consolidation, triaxial testing, physical-chemical composition by x-ray diffraction (XRD) and x-ray fluorescence (XRF), scanning electron microscope (SEM) and leaching tests were performed on all mixtures. Results indicate properties enhancement of the two soft soils used in this research through the introduction of 15% of WTS and 20% of VBA, enhancing internal friction angle, reducing cohesion and plasticity, serving as a geomaterial while encapsulating heavy metals. Thus, the use of WTS and VBA for strengthen the properties of soft soils indicate a sustainable and ecological application for these wastes within the framework of the circular economy.

9th International Congress on Environmental Geotechnics (ICEG2023)

Waste Reuse and Recycling