Recycling paper sludge waste (PSW) into inexpensive sheets for applications in household interiors, construction, and footwear is a sustainable approach to resource utilisation and pollution reduction. A flexible recycled sheet (FRS) in board form was developed using cellulosic-based PSW from the paper industry and a styrene-butadiene rubber (SBR) binder. Various SBR concentrations were tested to determine the optimal amount for superior mechanical properties. The produced FRS was characterised using Fourier transform infrared spectroscopy, thermogravimetric analysis, high-resolution scanning electron microscopy, and energy-dispersive X-ray spectroscopy. FRS made with 1000 g of PSW:300 ml of SBR exhibited enhanced mechanical properties, including tensile strength (62.32 +/- 0.51 MPa), elongation at break (51.99 +/- 0.94%), tearing strength (17.76 +/- 0.45 N/mm), and flexibility (6.98 +/- 0.24%). A biodegradation study, conducted per ASTM D 5988-03, assessed environmental impact by measuring carbon-to-CO2 conversion in soil over 90 days. All FRS samples showed similar degradation within the first 30 days, with FRS 5 degrading significantly faster thereafter due to its higher cellulose and hemicellulose content. This highlights the potential of PSW-based FRS as an environmentally friendly and mechanically robust material for diverse applications.

This paper utilizes industrial wastes, including slag powder, desulfurized gypsum, fly ash, and construction waste, to solidify municipal sludge and develop a new type of landfill cover material. To investigate the durability of solidified sludge under wet-dry cycles, this study systematically analyzes its mechanical properties-such as volume shrinkage rate, unconfined compressive strength, and permeability coefficient-along with microstructural characteristics like pore structure, micro-morphology, and hydration products. In addition, the impermeability of the solidified sludge cover under varying rainfall conditions was assessed using rainfall simulation tests. After 20 wet-dry cycles, the solidified sludge samples exhibited volume shrinkage between 0.56% and 0.85%, unconfined compressive strength from 1.31 to 4.55 MPa, and permeability coefficients ranging from 9.51 x 10- 8 to 5.68 x 10- 7 cm/s. Portions of the gelatinous hydration products in the solidified sludge experienced discrete damage, leading to an increase in microporous volume. However, the overall structural integrity of the solidified sludge was maintained. The 3-layer landfill cover system was constructed using engineering soil, coarse construction waste aggregate, and solidified sludge and resisted strong precipitation. The 40 cm thick solidified sludge acted as an impermeable layer and yielded a good water-blocking effect. This study provides data support the application and technical advancement of solidified sludge as a landfill cover material.

The utilization of industrial wastes as feedstock for binders in soil stabilization is a promising approach toward environmental consequences; however, the optimization of chemical compositions and gradation are commonly disregarded especially for binders derived from multiple industrial wastes. This study presents a novel framework for designing multiple industrial waste blends (MIWB) consisting of ground blast furnace slag (GB), fly ash (FA), silica fume (SF), and calcium carbide residue (CR) and assesses its feasibility and performance in soil stabilization. The concept of three chemical moduli (TCM) and the strength activity index (SAI) are applied to control chemical composition, and Dinger-Funk particle size distribution is adopted to attain optimal gradation. A case study exemplifies sediment stabilization utilizing MIWB designed, and sodium hydroxide (NH), sodium metasilicate nonahydrate (NS), sodium sulfate (SS), and aluminum sulfate (AS) are used as chemical additives, the mechanical and microstructural studies by Atterberg limits, compaction, unconfined compressive strength, onedimensional consolidation, cyclic wetting-drying, X-ray diffraction, scanning electron microscopy and nuclear magnetic resonance tests are comprehensively examined. The outcomes demonstrate that: (i) MIWB is more efficient than ordinary Portland cement (OPC) in enhancing the compressibility and durability of stabilized sediment, and the optimal mix design of the composite binder was 14.25, 47.5, 9.5, 23.75, and 5 wt% of GB, FA, SF, CR, and AS respectively. (ii) The sulfate additives can dramatically improve the strength development of designed MIWB stabilized sediment than that of alkaline additives, (iii) The C-S-H, C-A-S-H, and AFt crystals are identified as the primary reaction products, arising from pozzolanic reactions between active phases present in the industrial waste. (iv)The pore volume of stabilized samples is reduced due to the excellent filling and cementation effects, contributing to higher mechanical properties. In particular, MIWB has been applied and proven effective in engineering practice.

With progress in technology, soaring demand for lithium (Li) has led to its release into the environment. This study demonstrated the mitigation of the adverse effects of Li stress on tomato ( Solanum lycopersicum L.) by the application of waste materials, namely coconut shell biochar (CBC) and steel slag (SS). To explore the impact of Li treatment on tomato plants different morphological, biochemical parameters and plant defense system were analyzed. Tomato plants exposed to Li had shorter roots and shoots, lower biomass and relative water contents, and showed decreases in physiological variables, as well as increases in electrolyte leakage and lipid peroxidation. However, the application of CBC and SS as passivators, either singly or in combination, increased growth variables of tomato and relieved Li-induced oxidative stress responses. The combined CBC and SS amendments reduced Li accumulation 82 and 90% in tomato roots and shoots, respectively, thereby minimizing the negative impacts of Li. Antioxidant enzymes SOD, CAT, APX and GR reflected 4, 5, 30, and 52% and glyoxalase enzymes I and II 7 and 250% enhancement in presence of both CBC and SS in Li treated soil, with a concurrent decrease in methylglyoxal content. Lithium treatment triggered oxidative stress, increased enzymatic and non-enzymatic antioxidant levels, and induced the synthesis of thiols and phytochelatins in roots and shoots. Hence, co- amendment with CBC and SS protected tomato plants from Li-induced oxidative damage by increasing antioxidant defenses and glyoxalase system activity. Both CBC, generated from agricultural waste, and SS, an industrial waste, are environmentally benign, safe, economical, and non-hazardous materials that can be easily applied on a large scale for crop production in Li-polluted soils. The present findings highlight the novel reutilization of waste materials as renewable assets to overcome soil Li problems and emphasize the conversion of waste into wealth and its potential for practical applications.

This Study is focused on suitability of industrial wastes in cement stabilized soil. The investigation is based on Unconfined compressive strength (UCS) tests. Experimental work is carried out to compare the UCS of cement stabilized soil specimens with different proportion of industrial wastes like Iron ore tailing, Quarry dust, Fly ash and Bagasse ash. The mix proportion is designed such that clay content is maintained at 10.5% for fine grained soil and density of 17.5 kN/m3. It is observed that the mix comprising industrial wastes and fiber have improved the mechanical properties compared to cement stabilized soil. Fiber addition has improved post peak behavior of soil specimen. The Scanning Electron Microscopy (SEM) microstructure images depict soil particle flocculation, leading to an increase in compressive strength and Energy Dispersive X-ray Spectroscopy (EDS) studies suggest the use of industrial wastes with natural soil helps in strengthening of soil cement stabilization, as well as to minimize the environmental pollution.

Due to extensive sand mining, the depletion of traditional backfill materials is a significant concern globally. Unsustainable sand mining practices, driven by construction demand, result in environmental degradation and resource depletion. Alternative materials like coal-fired power plant bottom ash and plastic waste offer cost and eco-friendly advantages for backfilling. Reinforced soil walls, compared to traditional structures, accommodate more settlement and load, providing flexibility, resistance to static and dynamic stresses, and improved aesthetics. To mitigate lateral earth pressure on retaining walls, incorporating compressible inclusions between the backfill and the wall reduces stress, ensuring long-term stability. The current investigation examines the effectiveness of sand or geomaterial prepared from sand (S), bottom ash (10-50% by dry weight), and plastic strips (0.5-1.25% by dry weight) together as backfill, behind the wall to improve the deformation characteristics of the wall and reduce lateral soil pressure. At the interface between the wall and the backfill, geofoam with densities 11D, 16D, and 34D, where D is measured in kg/m3 was used as an absorber to reduce wall lateral movement, settlement, and lateral push acting on the wall. To determine the efficacy of geofoam inclusion, parametric studies were carried out with a range of factors, including geofoam density, backfill characteristics, and surcharge load on the backfill. The model retaining wall was backfilled with either sand or geomaterial under simple strain circumstances. Plaxis 2D numerical modeling was performed for similar conditions and backfill types showed test results from both approaches exhibit excellent agreement. Results from numerical analysis and experimental method gave an optimal mix of the geomaterial (Sand + 50% BA + 1% PS) and geofoam density (34D in case of settlement reduction and 11D in case of lateral movement reduction and earth pressure reduction) that can yield maximum reduction of earth pressure with minimal deformation characteristics was suggested. When 34D geofoam was laid behind the wall backfilled with S, 50% BA, and 1% PS resulted in 172% and 178% improvement in bearing capacities for tests conducted experimentally and numerically. The corresponding settlement reduction values were 73% and 75%. The wall deflection reduction at locations 300 mm (H1) and 500 mm (H2) from the base of wall and earth pressure reduction for 11 D as CI and same backfill were about 82%, 82%, and 43% respectively for both analyses. Conclusively, the provision of geofoam as CI at the interface of the wall and backfill manifests to be a feast alternative for improving the performance of the retaining wall in terms of increasing bearing capacity, reducing settlement, lateral deformation, and earth pressure.

This study sheds light on the engineering and environmental performance of lime-activated incinerated sewage sludge ash (ISSA) and ground granulated blast furnace slag (GGBS) treated Hong Kong marine deposits (HKMD) slurry by stabilisation/solidification (S/S) technology, which is proposed using as fill materials in reclamation projects. The S/S performance of the treated HKMD with distilled water and seawater under different salinities was investigated. The results show that seawater could help S/S treated HKMD gain strength by using activated industrial wastes (ISSA and GGBS). The hydration and pozzolanic reactions between ISSA, GGBS, CaO and clayey compositions in HKMD make contributions to the strength development, porosity decrease and heavy metals stabilisation, which is supported by the characterization analysis including thermo-gravimetric (TG) analysis, mercury intrusion porosimetry (MIP) tests, nitrogen adsorption/desorption isotherms (NAI), scanning electron microscopy coupled with energy-dispersive spectrometry (SEM-EDS) and the leaching test of toxicity characteristic leaching procedure (TCLP). Seawater of 1.8% salinity (18 g/kg) is better than the distilled water and seawater of 3.6% salinity as a substrate solution in the S/S treated HKMD, because of the highest unconfined compressive strength and lowest porosity in the treated samples. The highest pH may account for its highest strength under the 1.8% salinity conditions. The S/S process could effectively stabilize the contaminants regardless of the curing time and the salinity of the mixing solution, and the leachates from the stabilized HKMD are environmentally safe and meet the requirement of standard in Hong Kong on the recycling treated soil. Therefore, recycling wastes-ISSA and GGBS with lime can be used as an appealing binder to stabilize/solidify marine deposits as environmental-friendly reusable materials in reclamation projects.