The accumulation of waste glass (WG) from construction and demolition waste is detrimental to the environment due to its imperishable nature; therefore, it is crucial to investigate a sustainable way to recycle and reuse the WG. To address this issue, this study examined the mechanical strength, microstructural characteristics, and environmental durability-specifically under wet- dry (WD) and freeze-thaw (FT) cycles-of WG obtained from construction and demolition waste, with a focus on its suitability as a binding material for soil improvement applications. Firstly, sand and WG were mixed, and an alkali solution was injected into the mixture, considering various parameters, including WG particle size, mixing proportions, sodium hydroxide (NaOH) concentration, and curing time. Subsequently, the effect of WG grain sizes on micro- morphology characteristics and mineralogical phases was evaluated before and after the treatment through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and ultrasonic pulse velocity (UPV). The results revealed that reducing the WG particle size and increasing the WG/S ratio significantly improved the strength of the WG-treated samples. Additionally, decreasing the NaOH concentration and extending the curing time also positively influenced their strength. The UCS test results indicate that the particle size of WG significantly influenced the strength development of the samples, as the maximum compressive strength increased from 1.42 MPa to 7.82 MPa with the decrease in particle size. Although the maximum UCS values of the samples varied with different WG particle sizes, the values exceed the minimum criterion of 0.80 MPa required for use as a road substructure, as specified in the ASTM D4609 standard. Moreover, as WG grain size decreased, more geopolymer gels formed, continuing to fill the voids and making the overall structure denser, and the changes during geopolymerization were confirmed by XRD, SEM, FTIR, and UPV analysis. The optimum WG/S ratio was found to be 20 %, with strength increasing by approximately 3.88 times higher as the WG/S ratio shifted from 5 % to 20 %. In addition, the optimum NaOH concentration was determined to be 10 M, as higher molarities led to a decrease in strength. Moreover, UPV results indicate that WG-treated sand soils exhibited UPV values 9.4-13 times greater than untreated soils. The WD and FT test results indicate that WG-treated samples experienced more rapid disintegration in the WD cycle than in the FT cycle; however, a decrease in WG particle size resulted in reduced disintegration effects in both WD and FT conditions. In both the FT and WD cycles, the declining trend exhibited a stable tendency around the eighth cycle. Nevertheless, the WD cycling damage considerably intensified disintegration, causing a profound deterioration in the structural integrity of the samples. As a result, repeated WD cycles lead to the formation of microcracks, which progressively weaken soil aggregation and reduce the overall strength of the samples. Consequently, this green and simple soil improvement technique can provide more inspiration for reducing waste and building material costs through efficient use of construction and demolition waste.

This study investigates the physicochemical properties of Soil-Like Material (SLM) recovered from aged Municipal Solid Waste (MSW) dumps in Anantapur, Andhra Pradesh, India, and assesses its potential for reuse. The SLM, which constitutes 68%-75% of the excavated waste, was analyzed for key parameters including total dissolved solids (TDS), chemical oxygen demand (COD), electrical conductivity (EC), and heavy metal concentrations. Results revealed that the organic content of SLM ranged from 6% to 20%, significantly higher than that of local soils (1.5%). The leachate produced from SLM showed elevated levels of TDS (500-1,200 mg l-1), COD (150-270 mg l-1), and heavy metals such as copper (Cu), lead (Pb), chromium (Cr), and zinc (Zn). Cu and Pb concentrations were found to be 27 and 26 times higher than those in local soil extracts, posing substantial risks to groundwater and soil quality. Other metals, including nickel (Ni), arsenic (As), and cadmium (Cd), also exceeded permissible limits. These findings suggest that while SLM has potential for reuse, its high contamination levels require treatment methods such as soil washing, heating, or stabilization with additives like lime or fly ash to reduce environmental risks. Without proper treatment, the direct use of SLM could result in substantial ecological damage. The study highlights the importance of sustainable landfill site rehabilitation and the development of safe strategies for the reuse of SLM to mitigate potential environmental impacts.

The study explored the long-term efficiency of an integrated electrodialysis-forward osmosis (EDFO) treatment technology for nutrient recovery and its application in irrigating and fertilizing high-value crops. Results showed a stable energy profile with consistent electrical conductivity (EC) trends in both municipal and dairy digestates, highlighting the system's capacity to maintain ionic stability, essential for long-term operation. Fouling resistance was indicated by gradual and minimal declines in current density, reflecting stable performance after three cycles and reducing the need for chemical cleaning. A greenhouse trial assessed the impact of using treated and untreated wastewater for irrigation on plant growth and nutrient dynamics in southern highbush blueberry (Vaccinium corymbosum L. interspecific hybrid). The plants were grown in a soilless potting media and irrigated with a modified Hoagland nutrient solution (control), untreated municipal or dairy digestate, or recovered nutrient water from municipal or dairy digestate treated by the EDFO process. Leaf area and shoot biomass were similar among the treatments, confirming that wastewater irrigation did not adversely affect blueberry growth. Furthermore, pH levels in the potting media were near or within the optimal range for blueberry cultivation (4.5-5.5), while EC exceeded salinity thresholds for the crop (> 2 dS m(-1)) but did not visibly damage the plants, suggesting that salt levels were manageable with periodic freshwater flushing. Mass-spectrometry-based, non-targeted analysis detected significant reductions in organic pollutants across treatment cycles. In particular, pharmaceuticals and pesticides in untreated digestate were reduced by over 90 % post-treatment, affirming the system's efficacy in removing emerging contaminants that could pose risks in agriculture and consumers. Given the favorable nutrient recovery and contaminant removal, the EDFO system offers a sustainable solution for wastewater reuse, enabling nutrient cycling in agricultural systems and reducing freshwater dependence.

Calcium carbide slag (CCS), phosphogypsum (PG), and red mud (RM), three types of industrial solid wastes, were employed to improve tunnel muck for assessing the feasibility of their reuse. A series of indoor tests were conducted to investigate the effects of their contents on the physical and mechanical properties of the improved tunnel muck. Microscopic tests were also conducted to reveal the improvement and interaction mechanisms involved. Results indicate that the incorporation of CCS, PG, and RM can significantly improve and enhance the physical and mechanical properties of tunnel muck. The improved tunnel muck containing 2% PG and 6% RM shows higher early strengths as CCS content exceeds 4%. However, after curing for more than 14 days, the unconfined compressive strength (UCS) of the tunnel muck with 4% PG and 4% RM is the maximum regardless of the CCS content. Microscopic analysis shows that reactive substances in industrial solid waste react chemically with soil components, exchanging ions and forming cementitious products such as calcium hydroxide, calcium silicate hydrate (C-S-H), calcium aluminosilicate hydrate (C-A-S-H), and ettringite (AFt). They bind, fill, and encapsulate soil particles, compacting the soil and significantly enhancing the physical and mechanical properties of tunnel muck. Moreover, there is a notable mutual synergy between PG and RM, primarily attributed to their acid-base neutralization and the complementary action of reactive ions. The improved tunnel muck containing 4% CCS, 4% PG, and 4% RM demonstrates the highest enhancement efficiency.

The exponential growth of tunnelling projects worldwide necessitates efficient management of excavated soil, particularly from Earth Pressure Balance Tunnel Boring Machines (EPB-TBMs). This study investigates the temporal evolution of mechanical properties in EPB-excavated soil, focusing on the conditioning process's impact. Through a comprehensive literature review, gaps in understanding the soil's transition from a liquid-like state back to its solid form are identified. Existing studies touch on mechanical property changes over time but lack detailed temporal analyses. Our research addresses this gap by examining the recovery of soil compactability over time, crucial for its reuse. By conducting modified Proctor tests at different time intervals post-conditioning, we elucidate the relationship between soil properties and conditioning parameters. Our findings reveal a direct correlation between recovery time and total water content, influenced by added water and foam injection ratio. We demonstrate that different conditioning parameter combinations yield similar immediate properties but divergent recovery times, which are crucial for logistical planning and environmental suitability. This study offers valuable insights into optimizing EPB-TBM excavation logistics, enhancing soil reuse efficiency, and advancing sustainability in civil engineering projects.

The paper explores challenges arising from the existence of expansive clay soils, renowned for causing structural damage and exhibiting detrimental environmental effects. Implementing a novel approach, this study introduces the use of fly ash (Class F) and shredded face masks (FMs) to enhance soil properties. Fly ash (FA), known for its pozzolanic properties, is combined with shredded waste FMs to reinforce the soil. Remolded specimens underwent comprehensive laboratory testing, including Unconfined Compressive Strength (UCS), California Bearing Ratio (CBR), Swell Test, Consolidation Test, and Triaxial Test. The optimal blend identified as 0.9% FMs + 20% FA achieves an optimal equilibrium of strength, stability, and reduction in swelling. The UCS exhibited an increase with the addition of FA, and this improvement was further enhanced with the inclusion of 0.9% FMs, surpassing the specified subgrade CBR values. The percentage of swell exhibited a notable decrease from 5.9% to 1.8% with the incorporation of FA + FMs. This sustainable approach aims to conserve valuable resources and mitigate challenges associated with waste disposal along with the economic benefits to contribute to achieve UN SDGs 2030.

Shredded rubber from waste tyres has progressively been adopted in civil engineering due to its mechanical properties, transforming it from a troublesome waste into a valuable and low-cost resource within an eco-sustainable and circular economy. Granular soils mixed with shredded rubber can be used for lightweight backfills, liquefaction mitigation, and geotechnical dynamic isolation. Most studies have focused on sand-rubber mixtures. In contrast, few studies have been conducted on gravel-rubber mixtures (GRMs), primarily involving poorly-graded gravel. Poorly-graded gravel necessitates selecting grains of specific sizes; therefore, from a practical standpoint, it is of significant interest to examine the behaviour of well-graded gravel and shredded rubber mixtures (wgGRMs). This paper deals with wgGRMs. The results of drained triaxial compression tests on wgGRMs are analysed and compared with those on GRMs. Stress-strain paths toward the critical state and energy absorption properties are evaluated. The tested wgGRMs exhibit good shear strength and remarkable energy absorption properties; thus, they can be effectively utilised in several geotechnical applications.

Pulp and paper mill sludge is composed of cellulosic waste and clay and is rich in microorganisms that can benefit horticulture. However, its application in horticulture has received less research attention. Field and greenhouse studies were carried out to determine if sludge from a case study industry can replace the typical cellulosic additive utilized in hydroseeding, and the ideal application rate of a sludge-soil-seed mixture. The treatments were 0-100% sludge and soil by mass with a consistent mass of embedded seeds of Kentucky Bluegrass (Poa pratensis), Creeping Red Fescue (Festuca rubra), Perennial (Lolium perenne) and Annual Ryegrass (Lolium multiflorum). Seeding with a top layer of soil and 5 to 75% sludge gave the best outcome using a cellulosic additive after 3 weeks of growth. Mixtures containing 5-25% sludge resulted in the quickest seed germination rate. The cellulosic additive has the capacity to retain a higher volume of water but requires 15 times more material by volume. An increase in sludge increased water retention by 20%. Overall, the cellulosic additive in hydroseeding applications can be replaced by sludge without plant detriment. However, further testing is needed to determine long-term effects. [GRAPHICS] .

This study aimed to develop an energy-efficient process for treating highly saline textile wastewater (TWW) in a 10 m3/day pilot plant and evaluate forage sorghum irrigation with treated wastewater in terms of crop production and soil and irrigation device performance. The TWW treatment pilot plant, consisting of a coagulation/flocculation unit followed by a sand filter and an anion exchange resin column, produced treated effluent that complied with the permissible limits specified in the ISO 16075-2:2020 standard for Category C irrigation water. The corresponding average energy consumption was 1.77 kWh/m3. Reusing treated TWW for forage sorghum irrigation over a 13-week cycle yielded crop performances comparable with freshwater irrigation, with no negative impact on the irrigation system. Although soil profiles were similar between treated TWW and freshwater irrigation, both soils featured an increase in electrical conductivity, which may reversibly or irreversibly affect soil quality and damage salt-sensitive crops. These findings demonstrate the effective treatment and reuse of saline TWW for irrigating salt-tolerant crops, offering significant implications for industrial wastewater management and cropping patterns in arid and semi-arid regions. A 10-m3/day pilot plant was developed for the treatment of highly saline textile wastewater. The pilot plant demonstrated average removal efficiencies of 63% for COD, 97% for colour, 96% for TSS and 21% for EC. Treated effluent met ISO 16075-2:2020 standards for Category C irrigation water, with an average energy consumption of 1.77 kWh/m3. The use of treated wastewater showed sorghum crop production comparable with freshwater irrigation. The use of treated wastewater had no adverse effects on the irrigation system; however, it led to an increase in soil electrical conductivity.

Worldwide, an increasingly huge number of end-of-life tires (ELTs) are disposed of in landfills, illegally dumped, or otherwise unaccounted for, which causes significant environmental and socioeconomic issues. Finding sustainable engineering solutions to recycle and reuse ELTs, which transform them from unwanted waste into useful resources, has become a priority. In geotechnical engineering, researchers have performed laboratory and field tests to determine the mechanical properties of innovative geomaterials that consist of soil-rubber mixtures (SRMs) [i.e., gravel-rubber mixtures (GRMs)] that are obtained using recycled ELT-derived granulated rubber aggregates. Suitable engineering properties and low installation cost encourage the use of GRMs and SRMs in many applications, such as in free-draining energy-adsorption backfill material for retaining walls, underground layers for liquefaction mitigation and geotechnical seismic isolation systems for structures and infrastructures. However, due to the heterogeneity of SRMs, their ultimate adoption as geomaterials must be supported by constitutive relationships that can accurately describe their mechanical behavior under typical field loading conditions. The aim of the paper is to evaluate the effectiveness and limits of the hardening soil model with small strain stiffness (HS-small), which is present in many finite-element (FE) codes, to model the behavior of GRMs in geotechnical engineering applications. An extensive finite-element method simulation of drained triaxial tests was performed.