Environmental Geotechnics and Pollution Control

Flooding is one of the primary causes of losses from natural disasters in numerous regions worldwide, surpassing all other types of natural hazards in terms of damage. In recent decades, flood damage has been significantly severe due to the increase in the frequency and intensity of floods. Considering that levees are built for an established design life, it is essential to consider potential changes in loads due to atmospheric climate change. Climate variability may affect hydraulic loading and soil eroding with significant precipitation or during drought or high wind conditions. These atmospheric changes over time may affect the structural integrity of the levee. The dominating failure modes for typical ground conditions along rivers are slope stability, overtopping, through seepage, and underseepage. Several technologies can be applied to prevent levee failure, strengthen the levee, avoid overtopping or internal erosion, and ground subsidence due to changing groundwater. The most common ones are concrete columns, sheet piles, geosynthetics, and deep mixing using different binders. However, these technologies come out to be costly, in terms of materials. Moreover, the primary material of these interventions is cement. Nowadays, it is accepted that the cement industry is one of the two largest producers of carbon dioxide (CO2). The Sustainable Development Goals (SDGs) provide comprehensive guidelines for promoting sustainable development in terms of environmental, social, and economic dimensions in all sectors of the economy, including civil engineering. The study outlines the procedure to calculate the carbon dioxide emissions of different technologies for levee reinforcement. Considering a simple scenario, the technical suitability of the investigated technologies is analyzed, and the carbon dioxide emission is analyzed separately.

Microbially induced calcite precipitation (MICP) and Enzyme Induced Calcite precipitation (EICP) are sustainable soil improvement techniques. Sporosarcina pasteurii is a non-pathogenic bacteria widely used in lab-scale and field-scale studies of augmented MICP. Media optimization and the analysis of the growth kinetics of S. pasteurii are vital for the application of MICP process. The influence of pH, temperature, and urea concentration on the growth kinetics of S. pasteurii is already established from the previous studies. However, choosing an effective medium for bacterial growth can also significantly influence the growth kinetics and urease activity of S. pasteurii which is missing in most literatures. Keeping this in view, in the current study, the growth kinetics and urease activity of S. pasteurii (NCIM 2477, equivalent to ATCC 11,859) in four different media were analyzed. The best medium was then chosen, and a biomineralization test was performed to evaluate the precipitation efficiency and polymorph type. Further, at similar urease enzyme concentration, the EICP biomineralization test was conducted to analyze the precipitation efficiency and crystal morphology. Thus, the paper compares the precipitation efficiency and crystal morphology in MICP and EICP methods at similar concentrations. Such a study is pivotal to increase the efficiency of MICP and EICP to take these processes to large-scale applications.

In this study, the index and mechanical properties of perlite-geopolymer soils were examined through Atterberg limits tests, compaction tests, and unconfined compression tests. Perlite was added to the specimens at rates ranging from 0 to 50% based on the dry weight of the soil. The liquid limit and plastic limit of the specimens decreased as the perlite content increased. Increasing the perlite content of the soil led to a decrease in the optimum water content and the maximum dry unit weight of the specimens. The molarity effect of sodium hydroxide on the geopolymerization of perlite-added soil was also investigated. The presence of the liquid activator (sodium hydroxide) increased the unconfined compressive strength of the specimens. Among the specimens, those composed of 60% clay and 40% perlite, treated with a 4 M NaOH solution at 40 °C for 28 days, showed the best performance in terms of strength gain. Consequently, perlite-geopolymer soils were successful in increasing the strength of the soil. The treated soil transformed into a more rigid and stronger structure, greatly improving the geomechanical properties of the soil.

In the construction industry, treating weak foundation soil poses significant challenges due to its poor bearing strength and high compressibility. This experimental study focused on assessing the engineering and morphological behavior of weak soil stabilized using geopolymer to enhance its engineering performance and suitability for construction. Geopolymer is an eco-friendly alternative to conventional soil stabilizers as it creates a novel stabilization solution amalgamated with industrial waste. There are multiple phases of methodology involved in this study. Primarily, the characteristics of weak soil, such as its properties and deficiencies, are investigated. Subsequently, the formulation of amalgamated geopolymer with industrial waste such as Cashew nut shell ash (CNSA) at different proportions was prepared and applied to the selected soil sample. During the pre- and post-stabilization stages, a comprehensive test series examines the soil’s engineering behaviors. Next to this, the microstructure modification caused during stabilization was analyzed and also, the thermal expansive nature of the stabilized sample during thermal curing was investigated at different temperatures to understand the impact of geopolymer concentration. The results of this study are significant for the advancement of sustainable geotechnical engineering practices, as they provide valuable insights into the effectiveness of geopolymer-based soil stabilization techniques. These findings can be a valuable resource for future researchers, engineers, and stakeholders in the field of geotechnical engineering while also addressing environmental concerns associated with the sustainable utilization of industrial waste.

Methane (CH4) emissions from municipal solid waste (MSW) landfills pose a significant environmental risk due to CH4's high global warming potential and flammability. Modern landfills utilize gas collection systems to reduce these emissions; however, their effectiveness is often compromised by a limited radius of influence. The efficacy of conventional soil cover (SC), designed to limit landfill gas (LFG) release, varies based on factors such as CH4 concentration, oxygen availability, and soil properties. This study investigates the spatial variability of potential CH4 oxidation in SC systems to determine if CH4 oxidation occurs uniformly across the surface. To achieve this, a near-field scale rectangular tank (measuring 50 cm × 50 cm × 100 cm) was fabricated, and an SC system was established within it. This system includes a clayey soil layer (also known as a biocover layer), intended to decrease precipitation infiltration and facilitate microbial CH4 oxidation, which is overlaid by a sand drainage layer and topsoil. Various compositions and flow rates of synthetic LFG were introduced into the system. After the experiment, the system was dismantled to collect samples from various depths and locations to analyze spatial variations in moisture content (MC), organic content (OC), pH, and electrical conductivity (EC). Batch tests on selected samples from the biocover layer were conducted to measure potential CH4 oxidation rates. Results show significant variability in CH4 oxidation rates within the biocover layer, ranging from 71.9 to 260.2 µg CH4/g-day, with the highest activity observed at 70 cm below ground surface (bgs). Notable spatial variations in oxidation rates were observed, ranging from 95.3 to 148.4 µg CH4/g-day at 50 cm and from 34.7 to 102.4 µg CH4/g-day at 85 cm, in contrast to 70 cm bgs. Overall, the CH4 oxidation rates within the SC system were found to vary both in terms of depth and spatial distribution at the same depth.

This study analyzes the influence of grain size and their distribution of the deposits in the coastal environment and the sub environments. The samples were collected from three locations on the East coast of Tamil Nadu namely Sathurangapatnam, Mahabalipuram and Nemili beach. These three locations have distinct features. This enables us to compare the coastline process and their different sedimentary deposits. The Folk and Ward (1957) equation in terms of mean, standard deviation, skewness and kurtosis was used to identify the sediment distributions in the coastal environment. The sub environments are identified by bivariate plots. In all the three locations the presence of coarser sand was very less up to the maximum value of 10%. The remaining was medium and fine sands. The fine sands are dominant in Sathurangapatnam, the medium sand is dominant in the other two locations. It reflects the wave energy fluctuation in the dynamic wave energy creation and dissipation process. During the backwash, the wave gets back the medium-sized sand and leaves the fine sand on the beach due to high energy backwash. The sediment transport rate, sediment transport capacity, cross shore profile changes and the human interventions are taken into consideration in this study. This implies that the sand beach is an erosional type of beach. Mahabalipuram beach is identified as Stable/ Accretion beach. This study is used to mitigate risks to human settlements, ecosystem, and infrastructure.

Wildfires can be natural or anthropogenic occurrences with immediate and long-term effects on ecosystems, human health, hydrology, hydrogeology, and slope stability. Wildfire events are becoming more frequent due to climate change and human activity. Covering vast areas of land, ranging in frequency, intensity and severity, and duration, fires influence soil and vegetation’s physical, chemical, and biological processes. The long-term effects of widespread wildfires on soil processes are often unknown. Fires cause soil to become hydrophobic (lacking the ability to infiltrate water) and leave ash litter. Burned soil can also lose nutrients, which, along with lowered infiltration, can slow down revegetation. The run-off and loss of vegetation can lead to soil erosion, leaving a magnitude of aftereffects that can affect water and air quality, slope stability, and even human health. Methods suitable to treat, restore, and remediate burned soils depend on the fire’s severity and the ecosystem’s conditions pre- and post-fire. There has yet to be a one-size-fits-all solution to managing the aftereffects of wildfires because there are critical knowledge gaps on impacts on soils, the more significant ecological ramifications, and our ability to manage or remediate these impacts. This paper presents an overview of previous studies on remediating wildfire-impacted soils to better understand the impacts of post-fire management practices on ecosystems with differing characteristics. Still, there needs to be more guidelines about the effectiveness and feasibility of these remediation strategies.

In the framework of a research project financed by Next Generation EU Programme with the Italian Ministry of University and Research, the proposed note explores the possibility of producing lime from eggshells for soil stabilization purposes. The calibration of the production procedure of eggshell lime by calcination is supported by the use of thermogravimetric analysis and X-Ray diffraction and then verified by the fulfillment of International Standard requirements for lime in soil stabilization applications. Physico–chemical and mineralogical characterization of the produced lime is carried out and also preliminary results of a feasibility study of treatment of a clayey soil with the produced eggshell lime are presented. Proctor compaction, initial consumption of lime test and permeability tests in flexible wall permeameters were carried out on untreated soil and on the same soil treated with 4% of eggshell lime. Obtained results are compared with those obtained for the same soil treated with 4% of commercial quicklime.

Compacted sand-bentonite mixture is used as a buffer material in the nuclear waste repositories and solid waste landfills. The saturation state of the soil may change over the years. Therefore, it is important to observe suction behavior of soils under different conditions. One of the most important parameters affecting engineering properties of soils is the water-soil characteristics. The suction of sand-bentonite mixture depends on water content, bentonite content in the mixtures and time of hydration. In general, a decrease in the suction of bentonite was observed as the temperature increases, and an increase in the suction was observed as the dry density increased. In the present study, the suction behavior of the compacted sand-bentonite and sand-kaolin mixtures was determined by the filter paper method. As pore fluid tap water, NaCl and CaCl2 solutions were used. According to test results, while NaCl and CaCl2 solutions increased the suction value for kaolin and sand-kaolin mixtures, these solutions decreased the suction values for bentonite and sand-bentonite mixtures. The results shows the importance of pore fluid chemistry and mineralogy.

Changes in water content under climatic actions is one important process in several geotechnical issues, such as earth-structures deformation, foundation heave/settlement or slope failures seated in the vadose zone. Under certain conditions, these changes may act as a forcing condition for the underlying saturated water column and control cyclic pore pressure at higher depths. The deterministic modelling of these effects requires considering soil-atmosphere thermo-hydro-mechanical interactions under long time high-frequency series. Associated computational cost is a limitation for this type of simulation, particularly when going to large geometry or regional analyses. This article shows two strategies to estimate the soil hydraulic response in time under climatic series handled by Fourier decomposition. These strategies present similarities with techniques used to analyse soil response under seismic actions and propose to define soil transfer functions relating the input (climatic time series) to the output (water content or suction/pore pressure variation at several depths).

In many engineering projects, an important aspect is the depth of ground freezing, which is influenced by factors such as the type of material, thermal properties of the soil, water content, and climatic conditions including temperature, wind speed, precipitation, and solar radiation. The depth of frost penetration can be estimated using numerical or analytical methods, provided a large number of input data points are available. However, such data is typically not readily accessible. In such cases, similar accuracy can be achieved using simpler analytical and semi-empirical models calibrated from observations. Ground freezing, being a random process largely dependent on climatic conditions, which are also random, should be analyzed using probabilistic methods. The paper deals with the probabilistic method (Lieblein method) of the assessment of the depth of soil freezing. Based on data coming from observations conducted at 45 meteorological stations for over 45 years, calculations were made for the characteristic value of the zero isotherm depth with a probability of exceedance of 0.02. The obtained results illustrate the influence of climatic factors on the depth of freezing. Analyzing changes over individual decades, the pace of climate change for this phenomenon was shown, which determines the approach to this type of forecast.

When creating models of hydrotechnical structures and studying phenomena occurring in open channels, the selection of appropriate similarity criteria plays a crucial role. Laboratory tests on models are an effective method for verifying variants of solutions for the outfall, fortifications and the entire system of the tailwater of damming structures. However, the development of models is accompanied by a number of challenges and factors that, if not considered, affect the obtained results validity. This study demonstrates to summarize the hazardous factors accompanying the hydraulic modelling researches and proposals for their mitigative solutions met during ten years practice in laboratory works. Each identified problems is described in a separate section. Stage of identified problems occurrence was also given, as well as dedicated solutions. This results in a set of good practice advices formulation for further hydraulic modelling investigations. Model studies enable project optimization by testing different configurations and parameters without the need to build full-scale structures or installations. Moreover hydraulic systems will react to various factors in the future, which can be helpful in planning and forecasting.

The subject of this article is to assess the impact of a new branch of construction products, such as geosynthetics, on reducing the negative environmental impact of the construction sector. Recent decades have shown a rising awareness of advancing degradation of natural environment as well as overuse of natural resources caused by humanity. This is heavily caused by construction sector impact, as it follows growing population needs in householding, civil and industrial infrastructure. Civil engineering was discussed with examples of investments with negative and positive impact on the environment. Later, classification, definitions, functions, and properties of geosynthetics were presented, with special focus on geogrid applications. Working platform for crawling crane and heavy haul road were designed, in order to compare the results of traditional approach and polymeric geogrid usage in specified scenarios. The usage of geosynthetic product allowed to reduce the required thickness of the platform by 670 mm, while maintaining ultimate bearing capacity and factor of safety values on the same level as traditional solution. In the case of the design of the road under passage of heavy transportation, similar results were obtained, with the reduction of thickness of the platform equal to 655 mm. Carbon dioxide (CO2) consumption decreased by 50% in both cases.

Microbially Induced Calcite Precipitation (MICP) is extensively studied as an environmentally friendly soil improvement technique. The process of bio-cementation of the soil by microorganisms is present in the natural environment. It might be induced by ureolytic bacteria present in soil. In nature this process is slow, but since it is known how it goes, it can be accelerated. The study aims to present how bio-mineralization by MICP method affects the geotechnical properties of fly ash. In the presence of the Urease enzyme produced by the Sporosarcina pasteurii bacteria strain, urea hydrolysis occurs, so CaCO3 is precipitated as calcite crystals and bonds to grains or fulfil the material pores. The ureolytic bacteria are needed for the process of MICP as well as calcium ions Ca2+ present in the cementation solution. In this paper, laboratory test results of Unconfined Compressive Strength of Class F fly ash samples improved by the MICP method are presented and the process of sample preparation is described and discussed.

Plant communities respond to the conditions in which they grow. Different environmental conditions can lead to different plant communities. Human civilization changes habitat conditions and, in some cases, directly creates new habitats. Vegetation also responds to new habitats by altering its species composition. Species composition can be used to determine the degree of urbanization, the amount and frequency of disturbance, the amount of nitrogen and phosphorus, and the presence of salinization and landfill leachate. The vegetation of anthropogenic habitats provides a feedback loop from which we can learn how human civilization is changing its environmental conditions.

Landfill mining (LFM) of decade-old landfills and legacy waste dumpsites has indicated that about half of the excavated waste is primarily comprised of a mixture of decomposed organic matter, soil, sand, and other miscellaneous fine particles that are popularly known as landfill-mined-fine-fractions (LFMFF). Several field and laboratory investigations performed to determine the efficacy of reusing LFMFF revealed that heavy metals (HMs) leaching is the primary concern that restrained its potential utilization. Among the various parameters that can affect the leaching behavior of HMs, pH is the most significant one. The current study analyzes the leaching characteristics of four HMs (Cu, Cr, Zn, and Fe) from LFMFF by performing pH-dependent leaching test. The liquid–solid partitioning (LSP) curves of Cu and Cr revealed the amphoteric leaching behavior, demonstrating the elevated release at higher acidic and alkaline pH conditions, with minimal release at neutral pH levels. On the contrary, the LSP curves of Zn and Fe exhibit cationic leaching behavior where the released concentrations dropped monotonically as the pH level increased. The release of any particular HM is governed by the dissolution and precipitation of its oxide, (hydr)oxide, and carbonate compounds. The released concentrations of Cu and Zn were below the USEPA stipulated maximum contamination limits (MCL) within the permitted pH range of drinking water (6.5–9), but Cr and Fe concentrations frequently exceeded the MCL at every pH level. The study provides a comprehensive assessment of the release behavior of HMs from LFMFF under diverse environmental conditions.

Nitrate as a nutrient becomes a part of stormwater runoff originating from point and non-point sources such as fertilizers in agricultural fields, domestic wastewater, and livestock. This nutrient ultimately gets discharged into surface waterbodies. The removal of nitrate (NO3−-N) as nutrient using adsorption is an economically viable way to augment conventional treatment methods. The current study focuses on removal of nitrate from aqueous medium using bamboo-biochar provided with and without surface charge modifications. The biochar was produced in laboratory by slow pyrolysis of bamboo at 500 °C. Due to the presence of electro-negative surface charge over biochar surface, the affinity towards NO3−-N removal is low as a result of electrostatic repulsion between both the species. Thus, the prepared biochar was modified with 5% FeCl3 to increase metal oxides over biochar surface. This biochar was used to remove the nitrate present in stormwater runoff originating from various land uses based on major associated activities, namely commercial, industrial, institutional, and roads of urban area. The biochar was able to remove 45%, 46%, 65%, and 56% nitrate, respectively, from land use area commercial, industrial, institutional, and roads. The biochar modified with metal oxides have a relatively higher nitrate removal capacity than unmodified biochar due to change in surface charge to electro-positive. The Langmuir adsorption isotherm studies indicated monolayer adsorption while, Freundlich indicated multi-layered and heterogenous sites for adsorption of nitrate.

Heavy metal pollution resulting from anthropogenic activities poses significant environmental challenges, necessitating effective remediation strategies. This study investigates the phytoremediation potential of C. roseus, a medicinal plant, for cadmium (Cd) and zinc (Zn) contamination, with the application of sugarcane bagasse biochar amendment. Pot experiments included soil preparation, cultivation, and sample analysis to evaluate the impact of biochar on plant growth, metal accumulation and remediation efficiency. Results indicate that biochar amendment enhances root biomass production, reduces metal translocation from roots to shoots, and increases metal uptake by the plant. Spearman correlation analysis reveals a strong relationship between amendment rates, plant growth characteristics, and remediation indices, highlighting the efficacy of biochar in improving phytoremediation efficiency. The study concludes that C. roseus, augmented with biochar, demonstrates a promising phytoremediation strategy for Cd and Zn contamination. These findings emphasise the potential of biochar-assisted phytoremediation as a sustainable approach for mitigating heavy metal pollution in contaminated soils.

In the current context, industrial waste disposal poses a significant challenge for countries worldwide. To address this issue, an experimental investigation was conducted to develop a composite material utilizing copper slag (CS), rice husk ash (RHA), and geopolymer as binders. Tank tests were conducted to collect leachate samples at various incubation periods. Four physico-chemical parameters were analyzed for the leachate samples at 3, 7, 14, and 28 days of incubation. These parameters included pH, temperature (°C), electrical conductivity (μS/cm), and total dissolved solids (mg/L). The “WTW” Profiline 3320 series digital multi-parameter portable meter was utilized to measure the pH, temperature, total dissolved solids (TDS), and electrical conductivity (EC) of the leachate solutions. The results revealed pH values ranging from 6.91 to 11.01, temperatures ranging from 24.20 to 30.20 °C, total dissolved solids ranging from 686 to 10,910 mg/L, and electrical conductivity ranging from 1.02 to 16.28 mS/cm. In conclusion, the analysis of these physico-chemical parameters provides insights into the nature of the leachate solutions, offering valuable information for waste management strategies and environmental monitoring efforts.

Cement-bentonite barriers are structures designed to contain pollutants within contaminated areas and prevent their spread into the environment. However, since a part of these barriers is typically exposed to the atmosphere, desaturation and shrinkage can occur following changes in the water and humidity levels. Therefore, it is essential to study the long-term behavior of these walls based on the environmental conditions of the site to assess their durability and effectiveness over time. To achieve this, laboratory experiments were conducted to analyze the hydraulic behavior of these barriers under unsaturated conditions. The study aimed to evaluate the water retention curve and the impact of drying processes on the integrity and hydraulic performance of cement bentonite slurry walls. The results of the tests on barriers made with traditional binders (such as cement) offer important insights into their effectiveness and limitations. This data will serve as a starting point for evaluating the effectiveness of eco-friendly and sustainable binder materials.

This paper presents numerical analysis of nitrate contamination transport through soils. Two cases of drain, a trapezoidal canal and a well were considered in the analysis. Modelling of contaminant transport is carried out using GeoStudio programme. Particle tracking analysis established the flow paths of contaminant migration from source to drain. Advection–dispersion analysis showed contours of nitrate concentration in the subsurface with time. To control the contaminant transport, impervious vertical barriers of different depths were inserted at different locations in the numerical model. Results demonstrated that the nitrate concentration after 100 days decreased by about 40% with the inclusion of a vertical barrier of 6 m deep on the source side, whereas it reduced by about 95% when the depth of the barrier was increased to 10 m. For a trapezoidal canal drain, when the vertical barrier is placed on the drain side, the reduction in nitrate concentration was much lesser, indicating that the vertical barriers are more effective when they are placed on the source side. Effect of the depth of contaminant source with respect to the drain is studied though numerical simulations. Further, the nitrate concentration is analyzed with a well drain for 500 days for two different source depths of 2 and 2.5 m. Results showed that the nitrate concentration decreased with the increase in distance from the source. However, there was no significant change in the concentration at all locations, beyond 40 days, suggesting that the pollutant concentration has reached an equilibrium condition in 40 days.

Transforming agricultural and industrial waste into biochar through a process of thermal decomposition without the presence of oxygen stands out as one of the most efficient strategies for mitigating the impact of urbanization on the global climate. Biochar has a wide range of potential applications, including soil enhancement and carbon storage, and it has recently gained popularity as a valuable material for remediating soils contaminated with heavy metals. This study focuses on the utilization of moringa biochar for remediating soil contaminated with zinc, with a particular emphasis on assessing the geoenvironmental characteristics, such as soil pH, leaching potential, and compressive strength. The study examines the impact of different levels of biochar content (ranging from 0 to 10%) and curing periods (ranging from 0 to 28 days) on silty soil that has been artificially contaminated with 10,000 mg/kg of zinc. The results of the strength tests indicate that, when compared to untreated soils, the soil amended with 5% biochar exhibited a notable increase in strength of approximately 2.30 units after a curing period of 7 days. Furthermore, the introduction of highly alkaline biochar into the soil resulted in a significant rise in soil pH, creating favorable conditions for the encapsulation of zinc within the soil. The efficiency of immobilizing zinc reached approximately 84.5% in the soil treated with 10% biochar content.

The paper delves into the relevant concern of light pollution in urbanized regions, focusing on a case study conducted in Warsaw. Light pollution from excessive artificial lighting poses serious challenges to ecosystems and human health. The study employs drone technology to measure light intensity and capture nighttime photographs, enabling a detailed assessment of the extent and impact of light pollution in Warsaw. The research reveals the diverse manifestations of light pollution, ranging from disruptions in circadian rhythms to adverse effects on wildlife behaviour. By offering valuable insights into the multifaceted impacts of light pollution, the study advocates for informed decision-making and targeted interventions to foster sustainable and healthier urban environments. The findings underscore the importance of implementing better lighting policies to mitigate light pollution's adverse effects on human well-being and the environment. The research employed drone flyovers and lux-meter measurements to capture nighttime photographs and assess light intensity. Additionally, the study utilized the Sky Quality Meter to evaluate light pollution's impact on the night sky quality, offering valuable insights for urban planning and environmental conservation. Hence, the research enhances understanding of urban planning, public health, and environmental conservation, emphasizing the need for sustainable urban development practices to effectively address the challenges of light pollution.

Municipal Solid Waste (MSW) landfills play a pivotal role in waste management (WM), but they also introduce a spectrum of environmental challenges and risks. The study focuses on the issues of water quality and leachate chemistry changes at landfill sites. Additionally, the study explores the efficacy of proper landfill design and reclamation measures. Through the case study of the Łubna landfill in Poland, the paper aims to provide knowledge of how the landfill operation may impact environmental conditions and contribute to the broader discourse on protecting water resources at landfill sites. The paper emphasizes the significance of monitoring to derive a holistic view of the ecological consequences of MSW landfilling. The results confirmed the importance and effectiveness of reclamation work at the old waste landfill, which had been operated for many years without taking into account the principles and premises of environmental protection. The findings from this study are expected to inform environmental policymakers, WM authorities, and researchers, offering valuable insights into the specific challenges posed by MSW landfill sites. Furthermore, this research serves as an example for understanding the broader environmental implications of landfill activities and reclamation, providing a foundation for sustainable WM practices.

The suitability of landfill-mined-soil-like-fraction (LFMSF), which is a major constituent of landfill-mined residues, as a pH buffer material has been established by earlier researchers. Incidentally, this would promote the utilization of LFMSF as an anthropogenic (manmade) resource for treating acidic soils and neutralization of extreme pH industrial by-products such as red mud, phosphogypsum, incineration ash, etc. However, the apprehension is that when LFMSF reacts with materials of extreme pH, the leaching of heavy metals present in it might get enhanced/accelerated, which needs to be understood thoroughly to avoid any possible geoenvironmental contamination, by considering pH-dependent leaching of heavy metals present in it. Moreover, it is worth noting that such a study should give priority to pH stabilization, whose value will be influenced by processes such as dissolution, sorption, desorption and precipitation during the addition of H+ or OH−. Unfortunately, the time required for pH stabilization has not been considered by the existing studies. Hence, the present study was conceived to establish the time required for pH stabilization when the LFMSF reacts with acid/base of different concentrations. Following this, the concentration of leachable elements from LFMSF, at the end of the pH stabilization, was determined for the samples obtained from different landfill mining sites in India. It is believed that such a study would help in understanding the pros and cons of utilizing LFMSF as a sustainable anthropogenic resource for the neutralization of industrial by-products with extreme pH conditions.

The increased content of chloride ions in concrete pavers is typically caused with the penetration of chlorides from the environment into the material. Rock salt and de-icing agents are commonly applied to maintain sidewalks and roads during winter conditions. Sodium chloride (NaCl) is most commonly used due to its low cost and effectiveness. However, this compound causes extensive damage to sidewalks and poses an environmental hazard. Chloride corrosion of concrete pavers is associated with cyclic phases of freezing and thawing. The occurring changes in the state of aggregation of water on the surface of the pavement and in its internal structure cause stresses within the material, which consequently causes damage to the internal and external structure of the pavement. The study aimed to analyze the splitting tensile strength and surface roughness of concrete pavers immersed in a 10% solution of NaCl with an anti-caking agent for a period of 210 days. The splitting tensile strength of samples exposed to an aggressive environment was reduced by 55% compared to the control sample, and digital imaging with measurement of roughness parameters made it possible to observe the progressive degradation of the sample surface as a result of the chloride corrosion process.

Compacted bentonite and bentonite–sand mixtures have major importance as buffer materials in deep geological repositories, due to their low hydraulic conductivity and high swelling pressure. The main purpose of the buffer material is to seal the canister to prevent any high-level radioactive waste leakage. For this purpose, bentonite stands out as a good option for sealing due to its high swelling pressure. The swelling pressure of bentonite is affected by temperature changes. Therefore, in the present study various additives were added to bentonite and the effects of high temperature and additives on the swelling pressure of the compacted bentonite mixtures were investigated at room temperature and 80 °C. Boron minerals, namely colemanite and ulexite due to their low thermal expansion properties, ferrochrome slag and carbon fiber due to their high temperature resistance, were selected as additives. Additives were added to bentonite at the rate of 10% by dry weight. Also using modified conventional oedometer systems and uniaxial pressure test systems, a series of swelling pressure tests were performed at both temperatures. The modifications in the conventional systems allowed for a more accurate simulation of the conditions in deep geological repositories. Results indicate that high temperatures and additives significantly affect the swelling pressure, suggesting a potential change in the material's performance in high temperature conditions. This finding is crucial for the design and safety of deep geological repositories.

Brownfield sites have a variety of pollution that has accumulated over a long period of time or can be the result of a recent industrial accident. These sites are a receptacle for organic and inorganic pollutants. In particular, although Arsenic (As) is a naturally occurring element abundant in the earth's crust, contamination of soils has been aggravated by industrial activities. The bioaccumulation and non-degradability of As cause a variety of adverse health effects. Among treatment technologies, electrokinetic remediation (EKR) allows As extraction from soils. The technology of EKR is more effective than soil washing or flushing for fine-grained soils; it can be applied in-situ with low energy expenditure and is considerably more rapid than other techniques (phytoextraction, bioremediation). The purpose of this work is to apply EKR to evaluate its potentialities to remove more particularly As (but also Cd, Cu, Pb and Zn) from an accidentally contaminated industrial soil. Soil properties being very different as a function of depth (0–5 m), the main transport mechanisms of As with EKR were examined in each layer. The soil was collected from an industrial site (Le Havre, France) where an accidental spillage occurred in 2009. Liquid effluents containing potash arsenate infiltrated through surrounding soils. The results from laboratory investigation showed that the EKR technology provides variable efficiency from different soil layers owing to different gradation and fines content. This study addressed the necessary combination of different remediation technologies when the treated soil involve completely different horizons.

Pollution of water, wastewater and soil by oil can be caused by various sources, including industrial discharges, accidental spills, runoff from urban areas, and natural seepage, posing a significant threat to human health, wildlife, aquatic life, ecosystems, and the environment. This study investigated the feasibility of using eggshell waste in natural liners to prevent oil spill propagation. Subsequently, a two-stage experimental investigation was conducted to determine the effect of exposure time, eggshell type (ground and crushed) and clay on the adsorption rate. According to the analysis, the longer exposure time and large surface area of crushed eggshells resulted in the most excellent adsorption efficiency. It was confirmed that liner matrices containing clay minerals with crushed eggshells enhance the adsorption and retention of the pollutant. Overall, the highest sorption efficiency was obtained in crushed eggshells with 5 g clay and 150 min exposure times to the pollutant. In conclusion, natural clay liners modified with eggshells could efficiently protect the environment against oil spills or act as a lining material, preventing leachate from entering various areas (industrial, municipal, coastal, landfill, etc.).

Compacted clay-sand mixtures/sand-bentonite mixtures, when installed as landfill liners are subjected to saline intrusions due to the inorganic dissolved salts present in the leachate. Saline intrusions play a vital role in the desiccation crack formation in compacted soil liners along with gradation and initial compaction conditions when subjected to multiple wet-dry (W-D) cycles. In this research, expansive clay and the three clay-sand mixtures, featuring low (32%), medium (50%) and high (68%) sand contents, were utilized to prepare compacted specimens under Modified (MOD) Proctor conditions. Cyclic W-D tests were carried out on these specimens with distilled water (DW) and salt solutions (0.4 M NaCl, 0.4 M CaCl2 and 0.4 M AlCl3 solutions) as inundating fluids. Digital images of specimens were captured after the first, second and fifth drying cycles and analyzed using ImageJ Fiji software. The study reveals that the area of desiccation cracks decreases with an increase in the cation valence of the salt solution during W-D cycles. Higher osmotic suction and particle aggregation induced by salt solutions result in increased total suction and tensile strength, thus reducing the area of desiccation cracks. With the increase in the number of W-D cycles, the specimen with lower sand content became more susceptible to desiccation cracks, whereas the specimens with medium and higher sand content did not showcase any significant desiccation cracking even after multiple W-D cycles. The combined effect of the increase in sand content and salt intrusions reduced the area of desiccation cracks in specimens prepared using expansive clay and clay-sand mixtures.

Heavy metal-contaminated soils are frequently encountered, resulting from improper waste disposal practices and accidental spills, posing a significant threat to public health and the environment. Electrokinetic remediation (EKR) is proven to be effective in remediating heavy metal-contaminated soils, especially in low-permeable clays and heterogeneous soils. EKR involves applying a low electric potential gradient to facilitate contaminant transport—through various mechanisms including electrophoresis, electroosmosis, and electromigration—toward the electrodes for subsequent removal. The overall success of EKR depends on multiple factors, which includes soil type, contaminant nature and concentration, and electric potential, among others. The objective of the current study is to preliminarily assess the effectiveness of machine learning (ML) in predicting the EKR-induced migration and removal of heavy metals in contaminated soils using a comprehensive database derived from past laboratory studies conducted at the University of Illinois Chicago. This database encompassed various variables related to EKR, soil type, and contaminant properties alongside normalized distance from the cathode and the corresponding pH variations and metal concentrations. Four different regression machine learning (ML) models—random forest (RF), gradient boosting (GB), categorical boosting (CatBoost), and artificial neural network (ANN)—were trained and tested using the compiled database to predict pH distribution and metal migration post EKR. Notably, both the RF and GB models effectively predicted pH distribution post EKR. All the models except RF effectively predicted selected metal migration with similar migration patterns. However, none of the models effectively predicted EKR-induced migration for metals that exist in different oxidation states (e.g., chromium) at different pH conditions, or when trained on data containing diverse contaminants with wide-ranging properties. To address this, process-informed AI should be explored in future studies to accurately capture various complex underlying variables and processes to accurately predict the efficiency of EKR.

With the increase in the world population, there is an increase in the number of buildings and residential areas opened for use. However, in terms of engineering properties, there are many weak soil groups on the earth and it is not possible to use these soils without improving them. For example, it is known that clayey group soils have a high settlement problem and have low bearing capacity. These soil properties can be improved by using different additives in these soils. Where sustainability is also very important, the use of additives to be used in soil improvement as waste material or the selection of plant origin will provide an environment-friendly work that increases efficiency. In this study, it is aimed to optimize the zeolite-bentonite mixtures by determining the compression behavior at room temperature and 40°C using seaweed additive, that is, Zostera marina additive with its terminological name. Considering the areas where the soils will be used, it is aimed to examine the behavior of the average temperature value (~40°C), such as solid waste storage areas, around energy structures. Zostera marina has never been used for soil improvement before. However, it is a sea plant that has been used for many years in construction-related areas such as thermal insulation on the roofs of buildings in countries such as Denmark. Its resistance to thermal changes, its ability to preserve its organic structure without deterioration and for a long time, and its resistance to tensile and rupture show that soils can positively affect many engineering parameters such as compressibility and shear strength. The test results have shown that Zostera marina positively affected the compression behavior of zeolite-bentonite mixtures.

At the interface of renewable energies, this research takes a close look at the integration of geothermal energy, with a particular focus on the influence of the physical properties of unsaturated soils on geothermal energy transfer. Geothermal structures, which are essential for capturing energy from the soil, play a decisive role in heating and cooling buildings. By examining parameters such as soil composition, saturation level, water content, density, particle size, and arrangement, this study aims to derive differential equations to assess the energy balance at the soil surface, coupled with hydro-thermal transfer in unsaturated soils. A numerical model will be developed to simulate how climatic conditions influence geothermal energy transfer in these soils, taking into account their physical properties. The ultimate aim is to identify the most efficient soils for sustainable use of geothermal energy.

Renewable energy systems have become a global challenge, helping to reduce dependency on fossil fuels, to minimize the effects of climate change and to reduce green house gas emissions. Shallow geothermal energy (SGE) is one of these renewable energies that has become a sustainable alternative for conditioning buildings and infrastructure in many regions of the world. New solutions have recently been developed, including energy geo-structures, where SGE systems are coupled with heat exchangers in the foundations. The efficiency of these systems depends on a number of factors, among which the thermal properties of the soil and the design of the heat exchanger are major influences. The aim of this research work is to quantify and valorize this near-surface energy (shallow geothermal energy) using ground heat exchanger coupled to heat pumps. A transient numerical model based on the finite element method using the “COSMOL Multiphysics” software is established, taking into account the various thermal properties of the soil and the atmosphere-soil-heat exchanger interactions. The aim is to define the actual surface temperature during an annual reference period and the energy transferred to the building for use in heating and cooling in Algeria.

The fine fraction is defined as the sum of silt and clay fraction content. Depending on the standard, it may be a fraction smaller than 0.063 mm (ISO), 0.075 mm (ASTM), or 0.05 mm (former Polish classification). The fine fraction content is a parameter used to characterize example tailings or dredged offshore material. Potential for a power generation system using renewable energy, including wind and solar at tailings dams, is being considered as part of the sustainable development of abandoned mine areas. Therefore, recognizing the behavior of tailings as well as dredged materials is a very important engineering issue. As is commonly known, particle size distribution, next to the effective stress, void ratio, and stress history (for cohesive soils), is the basic factor influencing the mechanical behavior of soils. The quality of contact between grains affects the soil's ability to transfer stress. The proportions of individual fractions allow us to name the soil, but above all they affect the strength and deformation parameters of soil. This article presents the results of laboratory tests for six groups of soils with different fines content (from 12 to 99%). The soil was reconstructed in the laboratory, in sedimentation tanks. The samples were tested in a triaxial apparatus and oedometer. Triaxial tests were performed with multi-stage anisotropic consolidation and shear in undrained conditions. Based on the obtained test results, the influence of the fine fraction content on the slope of the compressibility curves of the tested soils was analyzed.

The reliable assessment of mechanical parameters (strength and deformation) of municipal solid waste is essential for slope stability analysis and the foundation's design on restored landfills. In remediated areas, the development of green energy infrastructure, such as photovoltaic panels and wind turbines, has become a common alternative. For the infrastructure development in restored areas, comprehensive site investigation is required. Assessing waste geotechnical parameters is extremely challenging due to the nature of the analyzed material. The composition, heterogeneity, and the degree of decomposition are only a few factors determining waste mechanical performance. The paper presents the evaluation of geotechnical strength parameters performed for the purpose of constructing the foundation of green energy facilities on a restored landfill site. The strength parameters of the waste were determined using CPT static investigation tests including geological boreholes drilled in the analyzed profiles. During the tests, cone resistance (qc) and sleeve friction (fs) were recorded. The values were used to determine the geotechnical parameters of waste. The anthropogenic material properties were classified as those represented by non-cohesive or cohesive soils, depending on the results obtained from CPT (mainly based on the friction coefficient Rf). Evaluated parameters were used to propose the safe development of green energy facilities at the restored landfill site.