Browsing by Issue Date, starting with "2023-08-01"
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- Water Treatment Sludge as Geotechnical Liner Material: State-of-ArtPublication . Marchiori, Leonardo; Albuquerque, Antonio; Cavaleiro, VictorThe periodical cleaning of the decanters at the plant generates solid wastes called water treatment sludges (WTS), a chemical compound similar to aluminum silicates. WTS’s properties have been studied for geotechnical purpose and it seems to be suitable for producing liner materials for landfills, dams, ponds, and lagoons which store and prevent soil’s infiltration of residues. Liners are usually shaped of soil and geosynthetics, their main properties required are compaction, compressibility and shear strength, chemical compatibility, and hydraulic conductivity. WTS to be considered as a soil substitute, it must be function like a soil, thus, for developing alternative materials, physical, chemical, mechanical, and hydraulic characterization laboratorial parameters are the first step to make viable its reuse. In this sense, the study aims to review the literature over the above-mentioned parameters in order to evaluate WTS as liner material. This review concluded that WTS have high heterogeneity in chemical and mechanical behavior due source of water and treatment processes. WTS’ water affinity affects plasticity behavior, and its incorporation into soils seems to contribute for a composite with pozzolanic characteristics, low specific gravity, finer granulometry, and mechanical stabilization. Although need attention on its chemical compatibility, the influence on shear resistance—increasing internal effective friction angle and decreasing cohesion—and the optimum ratio of introduction within soils for an alternative liner material. Nonetheless, there are lacks in literature over hydraulic conductivity, and long-term behavior, the use of the material in practice must be preceded by pilot tests or experimental landfills.
- Geotechnical Characterization Methodology of Water Treatment Sludge for Production of Liner MaterialPublication . Marchiori, Leonardo; Morais, Maria Vitoria; Albuquerque, Antonio; Cavaleiro, VictorClayey soils and geosynthetic materials are used as low hydraulic conductivity layers and environmental protection barriers in civil engineering works for storing wastes as covering and bottom impermeabilization layer structures, known as liners. Future shortage of clay materials and geosynthetic’s high costs are usual problems, aligned with the need of prevention of environmental impacts associated to wastes by industry infiltrating into groundwater, sustainable solutions are needed. The reuse of industrial waste materials follows directives of the circular economy when this application is expected to reduce construction costs, help preserve natural resources, reduce the use of synthetic materials, reuse industrial waste materials, and contribute to sustainability. Water treatment sludges (WTS) are generated by water treatment plants mainly from periodic washing of the sedimentation tanks and filters and seems to be suitable for a geomaterial replacement. To make it feasible, the most significant factors that need more investigations are index properties, physical and mechanical behavior, chemical compaction and resistance, hydraulic conductivity, and leaching potential. A methodology for different ratios of WTS, soil, and with or without additive needing, along with a laboratorial analysis of water treatment sludge sample were proposed to ensure the expected results and parameters for liner alternative material.