The effectiveness of zeolitic tuff (ZT) based geopolymer stabilization as a sustainable alternative to conventional cement stabilization for expansive soils is investigated in this study. Mechanical and geotechnical properties of geopolymer stabilized soil are evaluated in terms of ZT content, sodium silicate to sodium hydroxide (NS:NH) ratio and curing time. Soil improvement was assessed by laboratory tests, unconfined compressive strength (UCS), plasticity, compaction, and free swell tests. The test results show that the geopolymer stabilization increases the UCS significantly, as the NS:NH=2:1 mixture attains the maximum UCS of about 5.0 MPa in 28 days of curing, representing a 40 % increase over 12 % cement-stabilized soil. Furthermore, geopolymer-stabilized soils show a higher swelling reduction with free swell percentages as low as 0.25 %, a 42 % improvement compared to cement. The environmental assessment shows a 19 % lower CO2 emission per MPa of strength for geopolymer stabilization compared to cement-based stabilization, making it an eco-friendly choice. Pavement performance analysis using the Mechanistic-Empirical Pavement Design Guide (MEPDG) indicates that geopolymer-stabilized subbase layers improve structural integrity while reducing overall pavement rutting and fatigue cracking. Scanning Electron Microscopy (SEM) results validate the creation of a dense geopolymer matrix structure that enhances the strength and stability characteristics of soil materials. The study concludes that geopolymer stabilization using ZT with optimized NS:NH ratios delivers effective, high-performing, environmentally sustainable alternatives to traditional cement.

This study analyzes the effects of Hurricane Eta on the Chiriqui Viejo River basin, revealing the significant impact of extreme weather events on the hydrological dynamics of the region. The maximum rainfall recorded on November 4, 2020, reached 223.8 mm, while the flow in Paso Canoa reached 638.03 m3/s, demonstrating the magnitude of the event and the inability of the basin to handle such high volumes of water. Through a detailed analysis, it was observed that soil saturation resulted in direct runoff of up to 70.0 mm that same day, which shows that the infiltration capacity of the soil was quickly exceeded. Despite the damage observed, there are currently no advanced hydrological studies on extreme events in critical basins such as the Chiriqui Viejo River. This lack of research reflects a serious lack of planning and assessment of the risks associated with phenomena of this magnitude. One of the most critical problems found is the lack of specialized hydrology professionals, who are essential to carry out detailed studies and ensure sustainable management of water resources. In a context where climate change increases the frequency and intensity of extreme events, the absence of hydrologists in the region puts the resilience of the basin to future disasters at risk. The basin's hydraulic system demonstrated its inability to handle high flows, underscoring the need to improve flood control and water retention infrastructure. In addition, the lack of effective hydrological planning and coordination in the management of hydraulic infrastructures compromises both the safety of downstream communities and the sustainability of hydroelectric reservoirs, vital for the region.

Landslides are recognized as major natural geological hazards in the mountainous region, and they are accountable for enormous human causalities, damage to properties, and environmental issues in the Teesta River basin, Sikkim, India. GIS approaches are widely used in landslide susceptibility mapping (LSM) that can help relevant authorities to mitigate landslide risk. The binary logistic regression is applied to estimate the landslide susceptibility zonation (LSZ) in the upper Teesta River basin areas. The landslide inventory data are subdivided into training data sets (70%) for applying algorithms in models and testing data sets (30%) for testing model accuracy. The LSZ mapping is designed after analyzing multicollinearity test of 14 landslide CFs and the result shows that the VIF value is less than 10, and TOL is greater than 0.1, respectively. There is no multicollinearity for the 14 conditioning landslides factors. The upper Teesta River basin is categorized into five groups: very low-to-very high landslide susceptibility zones. The results highlighted that most of the middle and southern parts of the study region are highly prone to landslides compared to the other parts. The susceptibility of landslide in the upper Teesta River basin areas validated by performing the Receiver Operating Characteristics (ROC) curve, which showed an 83% confidence level. The present research demonstrated landslide vulnerability circumstances for the Teesta River basin, Sikkim, an area prone to landslides, emphasizing the need for an effective mitigation and management roadmap.

This study investigates the efficacy of microbial-induced carbonate precipitation (MICP) on the mechanical properties of poorly graded sand through a set of laboratory experiments. Unconfined compressive strength (UCS), ultrasonic pulse velocity, scanning electron microscopy, and calcium carbonate assessments were conducted to evaluate the influence of MICP under varying cementation concentrations, cementation ratios, and injection cycles. To this end, treated samples underwent 3, 14, and 21 injection cycles with cementation ratios ranging from 10 to 90% and molarities of 0.25, 0.5, 0.75, and 1 mol/L. Optimally stabilized samples were then subjected to 2, 4, 6, 8, 10, and 12 freeze-thaw cycles to evaluate their thermal durability. Correlation relationships were also developed to predict the compressive strength and stiffness of MICP-treated sand. Results demonstrated that MICP treatment effectively enhanced the UCS and stiffness by forming interlocking zones between the sand particles. Accordingly, the maximum UCS, secant stiffness, and constrained modulus were achieved at 14.98% calcite content using Sporosarcina pasteurii bacteria accompanied by a 50% cementation ratio and molarity of 0.75 mol/L over 21 injection cycles. Also, optimally stabilized specimens exhibited 70% and 90% retention in USC and stiffness after 12 freeze-thaw cycles, confirming their sustainability under harsh thermal conditions.

Background: The problem of toxic industrial waste impacting soil and water quality remains a significant environmental threat, yet comprehensive solutions are lacking. This review addresses this gap by exploring the effects of industrial waste on ecosystems and proposing strategies for remediation. Its aim is to provide a thorough understanding of the issue and suggest actionable solutions to minimize environmental damage.Methods: A comprehensive scoping review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data were sourced from major academic databases, including Science Direct, Scopus, PubMed, Academic Search Premier, Springer Link, Google Scholar, and Web of Science. A total of 105 relevant articles were included based on strict eligibility criteria. The review process encompassed identification, screening, and eligibility checks, followed by data abstraction and analysis.Results: The scoping review highlights the severe impact of toxic industrial waste on soil and water quality, emphasizing pollutants such as heavy metals (cadmium, lead, chromium), organic contaminants, and excess nutrients (nitrogen and phosphorus). These pollutants degrade aquatic ecosystems, causing acidification, eutrophication, and oxygen depletion, leading to biodiversity loss and the mobilization of toxic metals. Soil health is similarly compromised, with heavy metal contamination reducing fertility and disrupting microbial communities essential for nutrient cycling. Mitigation strategies, including cleaner production technologies, effluent treatment, bioremediation, and phytoremediation, offer promising solutions. These eco-friendly approaches effectively reduce pollutants, restore ecosystems, and enhance environmental sustainability, thus mitigating the long-term risks posed by industrial waste on soil and water quality.Conclusions and recommendations: The findings confirm that toxic industrial waste is a critical environmental threat that impacts both aquatic ecosystems and terrestrial soils. Immediate action is necessary to address ecological degradation. Recommended strategies include banning harmful raw materials, pre-treatment of waste, riparian buffering, bioremediation, and stricter regulations to control pollution and safeguard ecosystems.

This study aims to improve the forecasting performance of slope stability for impacting environmental sustainability and infrastructure safety predictions by using the Binary Particle Swarm Optimization BPSO technique is utilized to select relevant features from the dataset, thereby improving the overall effectiveness of the predictive models. The research includes 108 slope stability examples, with the dataset split between 70% training and 30% validation. The dataset comprises seven input parameters: cohesiveness, slope angle, unit weight, angle of internal friction, slope height, pore water pressure coefficient, and factor of safety. The objective is to classify the slope status, turning the problem into a classification task. To obtain optimal hyper-parameters for the SVM model, Grid Search was exploited. The accuracy of the slope stability predictions given by several models was assessed using receiver operating characteristic (ROC) curves. The results indicate that the BPSO-SVM model outperforms the standalone SVM and BPSO models, serving as a robust computational tool capable of accurately predicting slope stability to enhance the environmental sustainability.

Agricultural waste presents a significant environmental challenge due to improper disposal and management practices, contributing to soil degradation, biodiversity loss, and pollution of water and air resources. To address these issues, there is a growing emphasis on the valorization of agricultural waste. Cellulose, a major component of agricultural waste, offers promising opportunities for resource utilization due to its unique properties, including biodegradability, biocompatibility, and renewability. Thus, this review explored various types of agricultural waste, their chemical composition, and pretreatment methods for cellulose extraction. It also highlights the significance of rice straw, sugarcane bagasse, and other agricultural residues as cellulose-rich resources. Among the various membrane fabrication techniques, phase inversion is highly effective for creating porous membranes with controlled thickness and uniformity, while electrospinning produces nanofibrous membranes with high surface area and exceptional mechanical properties. The review further explores the separation of pollutants including using cellulose membranes, demonstrating their potential in environmental remediation. Hence, by valorizing agricultural residues into functional materials, this approach addresses the challenge of agricultural waste management and contributes to the development of innovative solutions for pollution control and water treatment.

Expansive soil poses significant challenges for civil engineers, leading to structural damage, particularly in lightly loaded structures. This study employs an innovative and sustainable recipe to stabilize highly expansive soil using the MicrobialInduced Calcium Carbonate Precipitation (MICP) technique by substituting conventional ingredients with olive mill wastewater and hydrated lime. A series of laboratory tests were performed to evaluate the improvement in Atterberg's limits, Free Swell, Unconfined Compressive Strength (UCS), and pH, in addition to a series of qualitative measurements, including X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Optical Microscopic Images, and bacteria growth rate. Different mellowing periods and different cementation concentrations were used. The proposed recipe results showed a 50% reduction in the soil's free swell value. The UCS of the treated soil using the proposed recipe was eight times that of the untreated soil and twice that of the soil treated with the traditional recipe. The SEM images showed flocculation and aggregation in the soil particles, with the voids becoming smaller and filled with calcium carbonate (CaCO3). The XRD results showed the formation of new CaCO3 particles. The optimized recipe demonstrated remarkable enhancement improvement and significant changes in soil physical properties and microstructure.

Using grout in construction and ground improvement has been common in various industries and construction projects. However, conventional grouts often need to be improved for their composition, durability, and environmental impact. Recently, there has been increased interest in exploring alternative solutions that are more sustainable and environmentally friendly. This comprehensive review aims to unravel the limitations of conventional grouts when exploring the potential of emerging biogrout technologies to achieve environmental sustainability in ground improvement. This review begins by examining the characteristics and limitations of traditional grouts, which highlights challenges such as inadequate durability and adverse environmental impacts. Then, the focus shifts toward emerging biogrout technologies, which harness the power of microorganisms to enhance soil stabilization. The principles, applications, and benefits of biogrout technologies are discussed thoroughly, along with case studies that showcase their successful implementation. A key aspect of this review is to highlight the environmental sustainability of biogrout applications in various civil engineering projects. Life cycle analyses (LCAs) are conducted to assess the environmental impacts of conventional grout, which sheds light on their drawbacks. In contrast, the environmental benefits and challenges that are associated with biogrout technologies are examined, which provides a comparative analysis between the two approaches. This review concludes by presenting prospects and challenges in this field. It discusses advances in conventional grout formulations to address their limitations and strategies to enhance the environmental performance of biogrout technologies. In addition, integrating sustainability principles into grouting practices is emphasized to achieve long-term environmental sustainability in ground improvement projects. Overall, this comprehensive review could contribute to the advances in sustainable ground improvement practices by providing insights into the limitations of conventional grouts and exploring the potential of emerging biogrout technologies. It could be a valuable resource for practitioners and researchers who seek sustainable solutions in ground improvement that align with environmental stewardship and sustainable development goals.

Co-culture systems of rice and aquatic animals (CSRAA) constitute a type of cultivation system that is important for blue-green revolution, as they provide environmental sustainability, economic profitability, and increased food productivity. However, little research has been conducted on how and to what extent CSRAA influences greenhouse gas (GHG) emissions. Therefore, we conducted a global meta-analysis to examine the responses of N2O and CH4 emissions to the transformation of rice paddy fields into CSRAA. Twenty-three published articles were included, which accounted for 75 effect sizes across three types of CSRAA: rice-fish, rice-crayfish, and rice-crab. The effect size (response ratio) of GHG emissions between rice paddies and CSRAA was calculated. The results showed that the CSRAA reduced N2O and CH4 emissions by 17% and 11%, respectively. Moreover, the rice-crayfish systems were the most effective at reducing N2O (32%) and CH4 (45%) emissions. The observed reduction in GHG emissions may result from changes in critical environmental factors. The effect size of N2O emissions was significantly positively correlated with increases in water-dissolved oxygen (P=0.0082) and soil ammonium (P<0.0001), whereas that of CH4 emissions was significantly negatively associated with increases in soil ammonium (P=0.0055) and soil redox potential (P=0.0041). We observed a significant quadratic linear relationship between N2O emissions and soil nitrate concentrations (P=0.0456). Overall, our study demonstrated the potential of CSRAA to reduce GHG emissions.