Department of Civil Engineering

Preserving stone-built cultural heritage from environmental degradation poses significant challenges, as moisture ingress and extreme weather accelerate weathering, leading to structural damage and escalating maintenance costs worldwide. While hydrophobic coatings show promise for protection, achieving long-term durability under harsh conditions remains elusive. The present research demonstrates a robust hydrophobic nanocomposite coating based on silica nanoparticles (SiNPs) functionalized with 1 H,1 H,2 H,2H-perfluorodecyltriethoxysilane (PFDTS), synthesized via alkaline hydrolysis of tetraethylorthosilicate (TEOS) and applied by spray coating to diverse heritage stones including sandstone, granite, and marble. The coatings achieve water contact angles of 130°–137° and sliding angles of 9°–10°, conferring exceptional self-cleaning properties that endure after saline exposure, wet-dry cycles, and marine simulations. Additionally, various water absorption tests, including the Karsten tube, ASTM D6489 surface uptake, ASTM C642 immersion tests, and droplet impact tests, showed a significant decrease in water absorption compared to uncoated stones. The overall results suggest that the water penetration at the coated surface was reduced by a factor of about 80–100 for the stone samples. This research study offers a scalable, cost-effective approach to enhance the longevity of cultural monuments, minimising preservation expenses and safeguarding irreplaceable historical assets for future generations.

Droughts are one of the most severe natural hazards, and its occurrences are increasingly exacerbated due to climate change. While numerous studies have analyzed drought occurrences using multi-model ensembles (MME) developed considering uniform weights to general circulation models (GCMs), biases inherent in these models impeded the attainment of reliable predictions. Also, studies conducted were region specific and were limited to considering a specific socio-economic pathway (SSP). The inconsistency in findings drawn across different SSPs limits the applicability of these results to implement best management practices to combat drought effectively. In this study, Drought Prone Index (DPI) built on the mathematical framework of Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) has been proposed. This index represents the frequency and severity of the possible drought events considering near future (2024–2060) and far future (2061–2100). Further, to overcome the limitation of bias, a multi-criteria decision-making (MCDM) framework integrating CRiteria Importance Through Intercriteria Correlation (CRITIC) and analytical hierarchy process (AHP) methods has been proposed to create differential weighted multi-model ensemble. The proposed framework is demonstrated considering India as study area. Findings of our study indicate a significant increase in rainfall and temperature ranging between 100–440 mm, and 0.75–3.5 °C across different SSP scenarios. Alongside a decline in rainfall in certain regions of Northeast India and the Western Ghats is observed from the derived spatial maps created using the data of developed MME. Spatial variation of DPI computed at a district level indicates that though the frequency of drought occurrences in the near and far future periods does not substantially increase, the severity of droughts is found to be intense. Findings highlight that it is imperative to consider the influence of climate change while assessing the droughts. These findings can assist policymakers and stakeholders in prioritizing resource allocation and implementing targeted mitigation strategies.

Owing to the urgent and escalating environmental crisis of water pollution through anthropogenic wastewater generated from various sources, the development of novel and innovative bioremediation strategies that are equally sustainable is highly necessitated. The present study embarks on an integrated omics-based exploration, complemented by a thorough literature synthesis, to critically evaluate and enhance hybrid algal-bacterial systems for effective wastewater treatment. Drawing on case studies and research from diverse geographic regions, we explore how these technologies inform the design and optimization of both engineered and natural treatment systems. The review emphasizes the integration of multi-omics data to support sustainable, targeted bioremediation strategies and underscores the cross-disciplinary convergence of environmental engineering, molecular biology, and systems ecology. This global and holistic perspective positions omics as a cornerstone for advancing the next generation of wastewater treatment solutions. Comprehensive analyses of the efficacies of different treatment methods used to remediate organic pollutants, heavy metals, nutrients, and contaminants of emerging concern (CECs), including antibiotic resistance genes (ARGs), were carried out, thus underscoring the pivotal role of microbial diversity and metabolic activity in the complex process of contaminant elimination. While prior research has predominantly focused on isolated components, the current study presents a holistic approach, merging state-of-the-art high-throughput metagenomics and transcriptomics techniques. This innovative combination illuminates the functional dynamics of microbial communities operating within the hybrid system under a range of operational conditions. The primary critical findings reveal significant shifts in microbial community structure and gene expression patterns, which are intricately linked to enhanced efficiencies in nutrient uptake and contaminant removal. In addition, the study also situates these findings within the expansive framework of omics-based bioremediation research, providing a clear and structured pathway for identifying prevailing knowledge gaps and directing future optimization efforts. Collectively, these contributions not only deepen our understanding of microbial community functions but also pave the way for designing next-generation bio-based wastewater treatment systems driven by the intricate interplay of microbial dynamics.

The equitable deployment of Electric Vehicle Charging Infrastructure (EVCI) is essential to address range anxiety and ensure widespread adoption of electric vehicles. This paper aims to identify the unserved areas of Delhi in terms of public Electric Vehicle Charging Infrastructure (EVCI) using a novel accessibility analysis approach. This study addresses accessibility gaps to address the Delhi EV policy's ambitious target of providing 3000-m access to public EV charging stations. Enhanced Two-Step Floating Catchment Area (E2SFCA) method is employed to quantify the accessibility levels to EVCI's at 100 m grid level. Global Moran I and Local Moran I analysis is conducted to identify areas where intervention is required. The location-allocation models indicate that installing at least 105 additional EV charging stations in the urban core and 150 in the peri-urban fringes would allow 93 % of the population to achieve the accessibility targets and an additional service coverage of 176.6 km2. The proposed methodology aims to achieve equitable accessibility to ECVIs which would lead to a better match of the supply-demand gap hence leading to the successful implementation of these infrastructures. The optimized yet balanced growth methodology and case-study for EV charging network expansion presented in this study is expected to aid policymakers in ensuring equity and spatial distributive justice in transportation electrification efforts.

Aerial ropeway transit (ART) systems are emerging alternatives to augment existing transit systems in congested cities in the Global South, especially in urban areas with limited transit coverage because of road width constraints or topography. Integration of aerial cable car stations to an existing transit network can improve the overall accessibility of various population segments with significant positive benefits in relation to reducing transport-related social exclusion. This study evaluated the impact of introducing ART in the city of Varanasi (India) and assessed the spatial accessibility improvements to critical facility locations such as heritage sites, educational institutions, hospitals, and employment centers. Several multimodal transit expansion scenarios were considered in this study and the potential benefits of each case were quantified using the two-step floating catchment area (2SFCA) method. A multi-criteria decision-making (MCDM) approach was subsequently employed for identifying the optimal locations of ART stops. Microlevel analysis findings suggest that the mean accessibility values could increase up to 10.92% in the first phase of the ART implementation, which could subsequently increase to 24.7% and 49.8% for the subsequent transit expansion scenarios. The study also investigated the Varanasi ART DPR prepared by Varanasi Development Authority (VDA) and showed that a significant increase of 16% in accessibility levels could be achieved if optimal stop locations identified in this study were implemented. The proposed two-step (2SFCA+MCDM) method for identifying the optimal locations of ART stations in a multimodal transit network is expected to be an effective tool for transit system redesign using place-based accessibility measures.

Solar energy is one of the widely accessible renewable energy resources, offering a wide range of applications from thermal uses to electricity production. The technology available to harness solar energy is popular; it has turned into a plausible alternative renewable source. This chapter provides insight into how solar energy can be harnessed for both residential and commercial purposes, highlighting its traditional roles in drying and passive temperature regulation alongside contemporary advancements in solar thermal and photovoltaic (PV) technologies. These modern applications not only produce electricity but also generate thermal energy for processes like desalination, water treatment, and cooking. The adoption of solar technology is promoted by both policy incentives and technological breakthroughs, paving the way for its widespread use across various sectors. India, setting a notable example, aims to achieve a renewable energy capacity of 175 GW, with solar energy contributing 100 GW. The rise of both grid-connected and off-grid solar PV microgrids reflects rapid development, with ongoing research into grid-tied inverters addressing reliability and power quality challenges. Moreover, rooftop solar PV systems are increasingly favored for rural electrification due to their simplicity and cost-effectiveness. This chapter aims to offer a comprehensive overview of solar energy applications, thoroughly examining the technical, economic, and environmental ramifications of these technologies.

Renewable energy sources, free of environmental risks, are vital for achieving net-zero CO2 emissions and addressing climate change to meet Sustainable Development Goals. This study explores the evolution of solar energy research using bibliographic coupling and keyword co-occurrence analysis of 6,460 articles from 1988 to 2024. The findings reveal a significant increase in solar power-related publications, with China leading in research output, followed by the United States and India. Top journals include Renewable Energy and Energies, with a growing focus on Energy and Engineering. This analysis serves as a vital reference for solar energy researchers and professionals.

Emerging trends in IoT and Drone technology are revolutionizing environmental monitoring through effective data collection and analysis. This research proposes a novel geospatial data sensing platform mounted on a Unmanned Aerial Vehicles to collect selected environmental parameters including moisture, temperature, and PM2.5. The designed platform is built using Arduino Mega micro controller, PM2.5 sensor, GPS sensor, and a DHT sensor enabling to collect geospatial data. The collected data is further stored on a SD card embedded within the designed platform. The stored data can be further processed and visualized using an open source GIS environment. For demonstration, the data is collected within a University campus located in Andhra Pradesh, India. The recorded data analysis shows that the mean temperature is 39.4°C with a variance of 9.2°C, mean humidity is 29.2% with a variance of 82.0%, and mean dust concentration is 143.6 mg/m3 with a variance of 5.3 mg/m3. The applications of the developed tool can be extended to various other potential applications such as precision agriculture, climate monitoring, and disaster management.

Climate change poses a risk to the human societies and environment, encouraging a shift towards clean energy sources. Among these sources, offshore wind energy emerges as a favorable solution, due to its steady and strong wind resources, coupled with mature technology. Establishing offshore wind farms requires substantial financial investment. However, uncertainties induced by climate change may not only impact the cost-effectiveness of offshore wind farms but also influence the suitability of regions for their development. Therefore, the present study presents a novel framework for identifying optimal regions for off-shore wind farms by considering future projections under the various Shared Socioeconomic Pathway (SSP) scenarios. A weighted multi-model ensemble (MME) of ten CMIP6 climate models was considered. Offshore wind energy resource are classified based on resource richness, stability, risk, and economic viability. Criteria Importance Through Intercriteria Correlation (CRITIC) method is used to assign weights to each factor, offering insights into their influence on wind resources. The findings reveal that projections for the SSP2-4.5 and SSP5-8.5 scenarios show that the western and northeastern offshore regions within the study areas have emerged as the top-ranking regions due to their abundant wind energy resources and favorable stability, risk and economic factors. By employing a novel methodology, this study produces suitability maps that identify promising wind regions for future development, providing important information for long-term planning in India’s offshore wind sector.

Incineration of municipal solid waste is increasingly being adopted in developing countries from the past couple of decades as a waste management strategy. This is driven by rapid urbanization, population growth and scarcity of land for landfills. MSW incineration reduces the volume of waste by 70–90% but still leaves behind substantial quantities of residual ash for disposal. Managing and disposing ash safely adds significant costs over just burning the waste, undermining the economics of incineration. The present study explores the potential applications of municipal solid waste incinerated (MSWI) ash as a landfill liner. This study provides a comprehensive characterization of both fresh and aged incinerated MSW ash (fly ash and bottom ash) collected from waste to energy plant (WTE). Analyzing the physicochemical properties of incinerated ash incorporating its mineralogy, morphology, and chemical composition is essential for its effective application in geotechnical engineering. This approach offers a sustainable alternative to traditional liner materials.

Municipal solid waste landfills require liner systems to prevent leachate migration into the environment. Liner selection typically focuses on engineering performance, cost, and ease of construction, with limited emphasis on sustainability. This study assessed the sustainability of four composite liner systems using the triple bottom line approach, considering environmental, economic, and social impacts, along with technical equivalence based on leachate infiltration rates. The four systems analyzed were: (1) geomembrane (GM) over compacted clay liner (CCL) (GM/CCL), (2) GM over geosynthetic clay liner (GCL) (GM/GCL), (3) GM over soil mixed with lime and cement (SA) (GM/SA), and (4) GM over fly ash mixed with bentonite (FAB) (GM/FAB). Life cycle stages-material extraction, construction, monitoring, and disposal-were evaluated. The study focused on DeKalb County Landfill in DeKalb, Illinois, USA, with environmental impacts quantified using the Eco-Indicator 99 and TRACI methods in SimaPro 8.0.1. Results showed that GM/FAB was the most sustainable liner in terms of environmental impact and second in economic and social considerations. However, GM/GCL was the most preferred based on economic and social impacts.

The utilization of Linz-Donawitz (LD) slag in cementitious applications has gained traction due to its widespread availability, offering a potential solution to reduce global warming. This study evaluates the impact of particle size fractions on the chemical, mineralogical, and dissolution characteristics of LD slag. Nine particle size fractions were analyzed, revealing significant variations in oxide content based on particle size. While CaO, Fe2O3, and SiO2 contents remain similar in higher (þ500 μm and þ1,000 μm) and lower (þ3 μm) size fractions, particles between þ3 μm to þ75 μm exhibit a 1.5% free lime content. Quantification using XRD-based Rietveld refinement indicates LD slag primarily consists of crystalline phases (quartz, calcite, portlandite, brownmillerite, wustite, and belite) alongside an amorphous phase, with amorphous content ranging from 40% to 60% across all sizes. The þ3 μm size fraction exhibits the highest belite, brownmillerite, and wustite content, with comparatively lower free lime content than other size fractions. Dissolution analysis in an alkaline environment shows a slightly improved dissolution behavior with decreasing particle size from þ150 μm to þ3 μm. Calcium exhibits higher initial dissolution rates than iron and silicon within the first three hours, with silicon becoming more prominent after twelve hours. Overall, this study offers a comprehensive analysis of the correlation between particle size and chemical/mineralogical composition, highlighting the potential for converting industrial waste into ecofriendly products.

The current paper explores the possibility of producing alkali-activated fly ash-based lightweight blocks with adequate properties at lower curing temperatures to use in various construction applications. Sodium-based alkaline activators are utilized to activate the fly ash. Two different curing temperatures are employed, 60 °C and 85 °C. The properties of the block, such as strength, density, and thermal conductivity, are evaluated. Aeration experiments reveal that the addition of Al powder to the paste leads to the collapse of the bubble structure. However, the addition of nano clay aids in stabilizing the formed bubbles, thereby preventing their collapse and maintaining the integrity of the aerated structure over time. The amount of nano clay depends on the quantity of Al powder added to the paste. Across all samples, strength is found to be inversely proportional to density and thermal conductivity. At 0.3% and 0.4% Al powder dosages, samples attained similar ultimate strength regardless of curing temperature, while density and thermal conductivity varied. The block achieved a strength of approximately 10.60 MPa and a thermal conductivity of 0.090 W/mK at a corresponding density of 450 kg/m³, which is higher than the IS standard codal provisions. The blocks were characterized using various analytical techniques such as XRD, FTIR, and SEM. The strength of the block depends on the reaction product formed during the activation process, with all techniques indicating the formation of stable sodium aluminosilicate gel. For samples cured at 60 °C, two new crystalline phases, trona and sillimanite, were observed. Trona is formed at the age of 28 days, while sillimanite forms at an early age, with its quantity decreasing over time. In conclusion, the study offers crucial insights into producing alkaline-activated fly ash-based lightweight blocks with satisfactory performance at lower curing temperatures.

The environmental impact of Portland cement production has intensified the search for alternative low-carbon cement. Reactive magnesium oxide cement has emerged as a promising option. The current study investigates the hydration behavior, strength development, and phase evolution of MgO and MgO-RHA blends cured under sealed and carbonation conditions. Two RHA sources with differing amorphous content and particle size were used. A detailed investigation was conducted using various techniques, including calorimetry, TGA, FTIR, XRD, Raman spectroscopy, and SEM. Results showed that higher glassy content and finer particles in RHA enhanced cumulative heat release, hydration product formation, and compressive strength. Carbonation curing further improved strength consistently by promoting the formation of nesquehonite and magnesium silicate hydrate. Quantitative XRD revealed that M-S-H formation was influenced by the consumption of periclase and unreacted glassy phase. Raman and FTIR analyses confirmed significant chemical and structural transformations, including the formation of brucite, nesquehonite, and carbonate phases. The D and G-band features in MgO-RHA samples suggested variations in carbonated products, influenced by processing conditions. Finally, SEM analysis revealed various carbonated products, M-S-H, and a dense microstructure. Overall, the study emphasizes the critical role of RHA properties and curing strategies in optimizing the performance of MgO-RHA systems for sustainable binder applications.

Microplastics (MPs) are emerging as contaminants posing serious environmental threats. Various types of MPs are being discharged into our water bodies, affecting the natural biogeochemical processes in the aquatic ecosystem, including modifications in carbon and nutrient cycling and imparting severe toxicity to flora and fauna. While several pieces of literature are available on the sources and types of MPs being discharged into various global water bodies, deep insights into the various biogeochemical processes affecting the environmental cycle still remain nascent. The present review highlights the key research avenues elucidating the governing mechanisms for changes in the biogeochemical cycle due to microplastic pollution. This includes different studies carried out on the impacts of MPs on the various environmental (carbon, nitrogen and phosphorus) cycles of the aquatic ecosystems. It also presents the toxicity aspects of MPs on the aquatic flora and fauna in different environments. Finally, we discuss the prospects that researchers need to focus on to provide a more comprehensive picture of the biogeochemical processes involved in MP pollution and to achieve sustainable solutions to abate MP contamination.

Deep marine sediments are rich in microbial diversity, which holds metabolic repertoire to modulate biogeochemical cycles on a global scale. We undertook the environmental microbiome inhabiting the Gulf of Kathiawar Peninsula as a model system to understand the potential involvement of the deep marine sediment microbial community and as a cohort in the carbon, nitrogen, and sulfur biogeochemical cycles. These gulfs are characterized by dynamic tidal variations, diverse sediment textures, and nutrient-rich waters, driven by coastal processes and the interaction between natural coastal dynamics and anthropogenic inputs that shape its microbial community diversity. Our findings suggest that carbon fixation was carried out by Gamma-proteobacteria with CBB cycle-related genes or by microbial participants with Wood-Ljungdahl pathway-related genes. Microbial communities involved in nitrogen metabolism were observed to be rich and diverse, and most microbial communities potentially contribute to the nitrogen cycle via processing nitrogen oxides. Bacteria belonging to the KSB1 phylum were also found to fix nitrogen. The sulfur cycle was spread throughout, with Verrucomicrobiota phylum being a major contributor. The varying napAB genes, significantly lower in the Gulf of Kutch compared to the Gulf of Cambay and the Arabian Sea, mediated nitrate reduction. Dynamics between these pathways were mutually exclusive, and organic carbon oxidation was widespread across the microbial community. Finally, the proteobacteria phylum was highly versatile and conceivably contributed to biogeochemical flux with exceptionally high abundance and the ability to form metabolic networks to survive. The work highlights the importance of critical zones and microbial diversity therein, which needs further exploration.

Conventional disinfection methods for drinking water are imperative in removing harmful pathogens. Then again, they often inadvertently give rise to disinfection by-products (DBPs) that are inherently carcinogenic, posing substantial health risks. Hence, exploring innovative and sustainable solutions to counter the side effects of these classical disinfection techniques is inevitable. This chapter thoroughly investigates the global challenges associated with DBPs in treated drinking water and provides a detailed overview of their prevalence globally. Emphasis has been placed on the prevalence and regulatory frameworks of trihalomethanes (THMs), the most predominant DBP species. Additionally, the chapter delves into examining different sustainable water management strategies aimed at reducing the formation of DBPs in treated drinking water, including source water protection, optimum use of disinfectants, and the implementation of advanced treatment technologies. Special attention is given to reducing THMs and their precursors, highlighting the effectiveness of membrane filtration, green adsorbents, and advanced oxidation processes (AOPs). The importance of integrating these strategies with robust monitoring systems and proactive policy measures to safeguard public health in the long term is also highlighted. Additionally, the chapter underscores the need for continuous research and development of innovative DBP control methods while advocating for a holistic and sustainable approach to drinking water management. Ultimately, this chapter aims to contribute to the ongoing dialogue on protecting public health and ensuring long-term water security by emphasizing sustainable DBP minimization strategies.

Pesticide poisoning through contaminated water, soil, or food is often linked to the widespread use of chemical pesticides in Indian agriculture. While many studies have reported the association between pesticide exposure and human health impacts, it has been challenging to disseminate this information to a broader population at state and national levels. Consequently, no state-level database exists correlating pesticide use with cancer rates in India. Here, we provide a comprehensive outlook focusing on the challenges of correlating these factors to develop a comprehensive geospatial database at the national level. A data-mining approach can help identify cancer hotspots, supporting informed policymaking.

This paper offers a comprehensive examination of the global footprint of pesticides consumption, revealing the disproportionate usage in high-income countries and highlighting the severe environmental and health risks posed by chemicals such as organochlorines and organophosphates. While numerous studies have been conducted on assessing the fate and transport of pesticides in the natural environment in developed nations, however, there is pressing need for similar research in developing regions, within South-East Asia, Latin America, and the African Union. Due to the cumulative nature of pesticides and the duration of exposure, it was expected that biota would show higher average, minimum, and maximum concentrations, along with increased variability. Water appears to be slightly more contaminated than sediment, but the most concerning revelation is the prevalence of pesticides in the air. Emphasizing the urgency of sustainable practices, the paper proposes microcosmic understanding on the degradation of pesticides, their contribution to antimicrobial resistance, and the development of environmentally friendly alternatives.

Incineration of municipal solid waste (MSW) along with energy recovery has been proven to reduce the volume of waste destined for landfills by as much as 90%. According to Indian solid waste management regulations, all municipal solid waste must be treated in composting facilities, waste-to-energy facilities, or other processing plants before being disposed of in landfills. This requirement not only lessens the spatial footprint of landfills but also contributes positively toward environmental sustainability. However, one challenge that remains is how to effectively reuse or dispose of the residues left behind after the incineration process. Even with comprehensive resource recovery, current estimates indicate that 25–35% of total MSW generated remains as residue that accumulates in landfills if not further used. Therefore, this research focuses on exploring the potential application of incinerated MSW ash as landfill liners. The study undertakes a meticulous analysis of both bottom ash and fly ash through extensive geotechnical characterizations. In order to gauge their suitability as landfill liners, the study conducts detailed geotechnical analysis on various aspects such as hydraulic conductivity and compressibility. Ultimately, this research promotes the massive utility of incinerated MSW ash, thereby encouraging a sustainable approach toward landfill management.