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Über dieses Buch

This volume contains selects papers presented during the Second International Conference on Environmental Geotechnology, Recycled Waste Materials and Sustainable Engineering, held in the University of Illinois at Chicago. It covers the recent innovations, trends, and concerns, practical challenges encountered, and the solutions adopted in geoenvironmental engineering, waste management, and sustainable engineering. This book will be useful for academics, educators, policy makers and professionals working in the field of civil engineering, chemical engineering, environmental sciences and public policy.

Inhaltsverzeichnis

Frontmatter

Electrokinetic Reactivation of Activated Carbon: Possibilities for the Treatment of the End-Waste Effluents

Activated carbon is a common adsorbent material for the retention of organic and inorganic contaminants. The spent activated carbon is usually regenerated with a thermal process. The electrochemical regeneration of the activated carbon has been proposed as an efficient and sustainable alternative to the classical reactivation methods. The electrochemical treatment consumes less energy and produces less CO2 than the traditional thermal activation. The electrochemical regeneration uses a DC electric current directly applied to the carbon specimen. The electric current desorbs and mobilizes the contaminants retained in the activated carbon. At the end of the regeneration process, the contaminants released from the carbon remain in the electrode solutions (anolyte and catholyte). Such end-waste effluents require treatment before their final disposal. This work analyzed the chemical composition of the end-waste effluents and proposed and tested various technologies for the separation/degradation of organic and inorganic contaminants. Furthermore, the end-waste effluents may contain valuable materials: metals, phosphorus, specific organics, etc., that can be recovered using various selective separation processes.

Claudio Cameselle, Susana Gouveia

Estimating Municipal Solid Waste Generation: From Traditional Methods to Artificial Neural Networks

Accurate quantification and prediction of municipal solid waste generation is a prerequisite for establishing an integrated municipal solid waste (MSW) system. Data about both quantity and quality of generated wastes as well as their temporal distribution are essential for planning the MSW system and capacities of the required facilities and equipment. Effective MSW system planning relies both on data availability and reliability and selection of the most appropriate data-driven method for estimating MSW generation. Traditional methods for estimating the amount of generated solid waste are established mostly on the basis of some elements such as number of population, waste generation coefficient per capita, and social-economic development of the region. Conventional methods for predicting MSW generation: weight volume analysis, material balance analysis, and load count analyses are basic methods for estimating the generated waste. Classical statistical models including regression analyses were mainly developed over the last three decades of the twentieth century to estimate MSW generation for specific region/city. Lately, time series models were developed and considered to be more appropriate for predicting waste generation for up to several decades. Artificial Neural Networks (ANNs), relatively new modeling concepts and tools, were successfully used in waste management problems and MSW generation due to their potential to capture temporal effects from data series and reliable predicting of future MSW generation. This paper presents a brief overview on the methods for estimating MSW generation and demonstrates implementation of ANNs to model and predict monthly waste generation for the City of Skopje.

Katerina Donevska

Bioremediation: Recent Advancements and Limitations

Bioremediation is a process that uses living organisms, mostly naturally occurring microorganisms, to degrade, detoxify, and/or transform contaminants from wastewater and contaminated soils. The technology is considered as a cost-effective and environmentally friendly approach, and has been used to decontaminate different kinds of contaminants, such as toxic heavy metals and organic compounds. With emphasis on biodegradation of volatile organic compounds (VOCs), one of the most common contaminants that occur both in developed and developing countries, this paper overviews some recent advancements and limitations associated with biodegradation. The most significant advancements include biodegradation of multiple contaminants and understanding of microbial process including the use of next-generation sequencing (NGS), and stable-isotope probing (SIP) techniques to identify functional microbial species. The limitations and future challenges include, but not limited to selecting and supplying stimulating materials, and promoting contact between contaminants, microorganisms, and stimulating materials in engineering practice.

Ming Zhang, Miho Yoshikawa

Consolidation and Hydraulic Conductivity of Soil-Bentonite Backfill Containing SHMP-Amended Ca-Bentonite in CCR-Impacted Groundwater

This study presents an assessment of feasibility on using soil-bentonite (SB) cutoff wall to control the migration of coal combustion residual (CCR) impacted groundwater. One-dimensional consolidation tests were conducted on model backfill containing sodium hexametaphosphate (SHMP)-amended calcium bentonite. Both tap water and simulated CCR-impacted groundwater were used to prepare the backfill specimen. Hydraulic conductivities of the specimens calculated from the consolidation results were also evaluated. The results indicated that the compression and swell indices for backfill prepared with CCR-impacted groundwater were 0.15 and 0.009, which was slightly lower than those for backfill prepared with tap water. In contrast, the two backfills possess hydraulic conductivity lower than 10−9 m/s, even under low loading pressure of 24 kPa, with regardless of the solution type used for sample preparation. This indicates little impact of the CCR-impacted groundwater on consolidation and hydraulic conductivity of the tested specimens. Thus the SB wall containing SHMP-amended Ca-bentonite has the potential to be an effective containment system for groundwater in coal ash disposal sites.

Yan-Jun Du, Krishna R. Reddy, Yu-Ling Yang, Ri-Dong Fan

Engineered Water Repellency for Applications in Environmental Geotechnology

Engineered water repellency offers a transformative approach to environmental geotechnology challenges. This paper reviews the use and potential for organosilanes to reduce leachability, control infiltration, increase strength, reduce erosion, reduce swell, and reduce effects of frost action. Organosilanes can be dissolved in water and mixed with soils and waste by-products using standard field compaction methodologies. Once cured, the treated material becomes hydrophobic. Treatment efficacy can be assessed in terms of contact angle and water entry head measurements. Evolving laboratory and field results will be summarized with a vision for future research and development.

John L. Daniels

Integrated Bioprocessing of Urban Organic Wastes by Anaerobic Digestion Coupled with Hydrothermal Carbonization for Value Added Bio-Carbon and Bio-Product Recovery: A Concept of Circular Economy

The major challenges associated with the anaerobic digestion of urban lignocellulosic biomass are its recalcitrance nature and the disposal of resulted digestate. In this study yard waste was thermally pretreated to overcome inherent recalcitrant nature during anaerobic digestion. The resulted digestate after anaerobic digestion, which poses a serious land disposal problem was hydrothermally treated to produce energy-rich solid biofuel knows as hydrochar. After pretreatment the biogas production was improved from 328 to 364 mL/g VS. Then hydrochar prepared from the digestate at a temperature of 180 and 200 °C for a treatment duration of 6 h. The produced hydrochar had a calorific value in the range of 20–23.5 MJ/kg as compared to 15 MJ/kg for raw digestate. The present research on integration of anaerobic digestion and hydrothermal carbonization not only improved the bioenergy production but also minimized the waste production.

Sagarika Panigrahi, Hari Bhakta Sharma, Brajesh K. Dubey

Geoenvironmental Investigation Methods Used for Landfills and Contaminated Sites Management

One of the most important activities when preparing a land reclamation project of brownfields is a comprehensive analysis and documentation of subsoil conditions at the site. The paper presents the site investigation methodology applied for the purpose of preparing land reclamation project for a number of challenging case studies, located in Poland. These are mainly post-industrial brownfields like steel plants and old municipal landfill sites. The paper presents the range and methodology of contaminated soil survey, waste morphology and composition analyses as well as documentation of obtained results. The research consisted of both, site investigation and laboratory tests. A detailed analysis of the results allowed precise determination of soil contamination indicators, environmental impact zones, and volumetric capacity of contaminated soil. On the basis of methods such as geoelectrical tests, boreholes, geodetic surveys, and laboratory chemical analyses of samples, maps of contamination impact zones were prepared, which at the final stage allowed completing complex brownfield reclamation plans and works for a number of case studies.

Eugeniusz Koda, Piotr Osiński, Anna Podlasek, Magdalena D. Vaverková

Minimizing the Impact of Groundwater Pumping on the Environment: Optimization Strategies

Long-term Groundwater pumping alters the environment and groundwater availability and thus affecting both the local and regional environment in a significant way. There are many purposes for which the groundwater has been abstracted in large quantity thus creating an unscientific way of management of the groundwater, leading to jeopardizing the sustainability of groundwater availability on a long-term basis. In this paper, we would be discussing one case study dealing with the groundwater modeling of open-cast mines with the development of an Integrated groundwater model to evaluate the impact of mining and the irrigated agriculture in the surrounding environs, on the groundwater status as well as to determine the time-period/year when the newly proposed mines without any increase in total pumping of groundwater. The study includes estimating groundwater recharge and developing a three‐dimensional steady‐state groundwater flow model exclusively for mine pumping simulation. The model has been utilized to evaluate the impacts of changes in groundwater pumping under the mine expansion scenario. In addition, simulation runs were made with the developed model to assess the impacts of recharging into the aquifer systems through the proposed recharge structures on groundwater and the surrounding environments and for various scenarios that vary depending upon the current as well as on the future conditions of water use. The other case study was in connection with the dewatering optimization in a metro rail tunneling construction. The requirement of maximum allowable drawdown necessitates the need for pumping and injection simultaneously and the optimal pumping wells and recharge wells location as well as the quantum of pumping and injection have been arrived at for 5 typical tunnel construction locations in a metro city of India. The engineering lessons learned, and the environment-friendly groundwater pumping plans are the major outcomes of these research works, which would be highlighted.

S. Mohan

Numerical Modeling of Landfill Processes: Complexity Versus Practicality

Bioreactor landfills are emerging as a sustainable means of municipal solid waste (MSW) management due to enhanced rates of waste decomposition which leads to early waste stabilization in landfills along with other short-term and long-term benefits. Currently, no well-established procedures or design guidelines exist to design and operate such landfills safely and effectively. This largely stems from the fact that there is no clear understanding of the fundamental processes and their interdependencies that influences the behavior of the waste and consequently the overall performance of a bioreactor landfill. Mathematical modeling of the major landfill processes (hydraulic, mechanical, biochemical, thermal) and their interrelated behavior using numerical methods is a useful tool in understanding the landfill performance and has been carried out ever since the late 1980s. Several researchers have developed numerical models to simulate the behavior of MSW in landfills with varying mathematical complexity. However, most of these models don’t find their application in the current state of practice, although many of the simpler models are increasingly welcomed by landfill owners and design professionals. This paper briefly summarizes the important concerns regarding the development of numerical models for modeling of landfill processes and their applicability in practice. Further, the key technical challenges that need to be addressed while developing a numerical model are discussed. The purpose of this paper is to have the landfill modelers embrace the need for a balance between the complexity and practical applicability of the model for the design and operation of bioreactor landfills.

Girish Kumar, Krishna R. Reddy

Status of C&D Waste Recycling in India

A major portion of C&D waste is generally dumped in landfills or unauthorized places in India causing considerable ecological damage. Several barriers such as inadequate regulations, lack of incentives, lack of awareness about recycling techniques, and unavailability of guidelines have been reported to hinder setting up recycling facilities in India. Amidst challenges, few recycling facilities have been commissioned and are operational in different Indian cities. A rich description of the cases helped us in tracing the evolution of recycling in India over a timeline. A multitude of factors including a pro-active urban local body, R&D efforts from PPP partner cum recycler, demonstration projects using recycled aggregates with the support of Central Road Research Institute, extensive support from the Government of India’s Ministry of Urban Development, the framing of standards and guidelines with the help of various professional bodies were found to be contributing to the successful development and operation of India’s first C&D waste recycling facility. Following this success, several plants were commissioned in other cities mimicking the same operational model. Insights discussed in the paper could be very useful for policymakers in evaluating various interventions for promoting C&D waste recycling practices in other regions and countries.

Mohan Ramanathan, V. G. Ram

An Ontological Analysis of Challenges Involved in Urban Solid Waste Management

Solid waste is a heterogeneous mixture of solid material (biodegradable, non-biodegradable, and inert) that does not have any further use to the society. Research studies suggest an annual per capita rate of increase in solid waste of 1–1.33%. The increasing quantity of such waste is resulting in serious health, aesthetic, environmental, social, and economic problems due to lack of appropriate planning and management. This necessitates the implementation of suitable policies to reduce the risk at all the stages starting from generation and ending with disposal of waste. Generally, the management of solid waste encompasses generation, segregation, storage, collection, transportation, recycling, processing, and disposal. This article presents a logically constructed ontological framework of urban solid waste management. It gives importance to waste management policy, functional elements of waste management, types of waste, sources of waste generation, people involved in waste management, and benefits of solid waste management. It shows the pathways to address the challenge to achieve sustainable solid waste management in the cities. The ontological framework encapsulates a total of 7 * 8 * 3 * 6 * 11 * 5 = 55,440 possible components of the challenge. A critical analysis based on primary and secondary data on urban solid waste management using the framework in Bengaluru, India will help in developing strategies to deal with solid waste. It can be used to systematically map the state-of-the-research on and the state-of-the-practice of urban solid waste management, to discover the gaps, and to bridge the gaps in waste management policy-making.

Shwetmala Kashyap, Arkalgud Ramaprasad, Chetan Singai

Development of New Precursors for One-Part Alkali-Activated Geopolymer Using Industrial Wastes

Conventional two-part alkali activation has many drawbacks: the hazardous activating solution, which makes it less friendly to handle and the absence in long-term availability of its main precursors such as fly ash and ground granulated furnace slag. This research aimed to develop a one-part alkali-activated cement, which is free of chemical solutions. A blend of alumina-silicate rich materials with adequate alkaline content to minimise the limitations associated with the current (AAC) relating to source materials was utilised. At the same time, applying alternative activation methods such as thermo-mechanical activation, alkali-thermal activation or thermo-chemical activation of new (AAC) precursors were investigated. Materials were analysed in terms of their physical, chemical and metallurgical properties to understand the changes after thermal activation. Enhanced compressive strength was recorded from individual thermal activation of the materials at 450 °C and 950 °C.

Monower Sadique, Abdullah Kadhim, William Atherton, Patryk Kot

Waste Management in Textile Industry—A Novel Application of Carbon Footprint Analysis

The higher quantities of water and a wider spectrum of dyes and auxiliary chemicals used impart a complex nature to combined effluent from various textile manufacturing units. Standards for color, organics, and dissolved solids are becoming stringent with time and regulators are in demand of zero liquid discharge units. For any zero liquid discharge facility, the major concerns include higher energy consumption for reject management and the generation of hazardous solid waste. As per the government regulations in Tamil Nadu, India, all the textile industries with a daily effluent discharge of more than 25 kiloliters must set up a zero liquid discharge facility. This has led to the accumulation of million tons of hazardous solid waste in the premises of textile manufacturing units. A carbon footprint is a measure of the total amount of greenhouse gases emissions of a defined person, organization, or a region associated with certain activities, production processes and life cycle of a product. The application of carbon footprint analysis to different waste management options can effectively help in the quantification of the overall environmental impact. The analysis performed can give key inputs to the stakeholders in the decision-making process regarding waste management in textile industries. Based on the methodology applied as per IPCC guidelines, the carbon footprint of a zero liquid discharge textile manufacturing facility in south India was found to be 10598.31 tCO2 equivalents per year. Sustainable waste management in textile industries plays an important role in minimizing the overall environmental impact of this continuously growing industry.

S. Mohan, Ninad Oke

New Ternary Blend Limestone Calcined Clay Cement for Solidification/Stabilization of Pb2+ Contaminated Soil

The use of supplementary cementitious materials (SCMs) in engineering applications has been gaining more attention recently. SCMs such as calcined clay (CC) and limestone (LS) used for the clinker substitution over 50% during the cement manufacturing process makes an effective low clinker cement blend called limestone calcined clay cement (LC3). In the present study, the effects of LC3 binder on pH, leaching, and strength performance of lead (Pb) contaminated soil are investigated. Toxicity characteristics leaching procedure (TCLP) test was conducted to evaluate the leaching potential, and unconfined compressive strength (UCS) test was conducted to assess strength characteristics. The TCLP test results show that the leached Pb concentrations in the LC3 stabilized samples were well below the regulatory limits after 14 days of curing, and the UCS strength values increased with the increase in the curing time. Therefore, the use of new ternary blend LC3 can be used as a sustainable and environmental-friendly additive for the remediation of heavy metal contaminated soils.

Anand V. Reddy, Chandresh H. Solanki, Shailendra Kumar, Krishna R. Reddy

A Study on Evaluating the Usefulness and Applicability of Additives for Neutralizing Extremely Alkaline Red Mud Waste

The chemico-mineralogical compositions of red mud lead to its abnormal pH (>11), rendering it unusable as a resource material for civil engineering applications. Such extreme alkalinity accentuates the dearth of contriving a solution to ensure the acceptability and reutilization of the waste. Curing period has considerable significance in the context that the previous studies reported reversal of pH of the red mud after neutralization. Thus, efforts are made in the present study to evaluate the usefulness and applicability of a variety of additives for neutralizing the red mud waste. Additives such as lime, ground granulated blast furnace slag, fly ash, gypsum in different proportions, and acids such as nitric acid and hydrochloric acid of varying strengths were employed, aiming at investigating the alkalinity mitigation capacity in the red mud. The results demonstrated a substantial reduction in the alkalinity levels of the red mud immediately after treatment, but the post-neutralization pH results exhibited noteworthy reversal with time. It has also been found that the type of neutralizing additives has considerable influence on the chemistry which in turn might have affected alkalinity levels in the red mud.

Manas Chandan Mishra, N. Gangadhara Reddy, B. Hanumantha Rao, Sarat Kumar Das

Contribution to the Remediation of Saline Soils by Electrokinetic Process: Experimental Study

Salinization affects ecosystem biodiversity, human health, agricultural productivity, as well as engineering and construction infrastructure. In Algeria, many arid, semi-arid, and near-coastal areas are suffering from soil salinization for more than two decades. In order to restore contaminated soils (saline), the electrokinetic process was tested in laboratory to study the mobility, migration, and elimination of ions (salts) in the soils of two regions of Mostaganem and Relizane (north-west of Algeria). The electrokinetic method is one of the most promising fine-grained soil decontamination processes. In this work, the variation of the electric current, the electro-osmotic flow, the pH, and the rate of elimination of the cations, such as sodium and calcium according to the treatment duration, were determined. According to the results obtained, the electrokinetic treatment proves to be a new technique used successfully, reliably, and inexpensively. It allows the remediation and restoration of fine-grained soils affected by salts. Our research demonstrates the economic and environmental value and the efficiency of electrokinetic technology, which is an innovative process. It deals very effectively with the depollution and remediation of saline soils and helps to inhibit the scourge of soil salinization and environmental pollution.

Faiza Klouche, Karim Bendani, Ahmed Benamar, Hanifi Missoum, Mustapha Maliki, Laila Mesrar

A Case Study Sequel: Sustainable Remediation Using Succession Crops for PAH Impacted Soil

A site in northern Illinois was impacted with polycyclic aromatic hydrocarbons (PAHs) in soil from historical foundry operations. Three PAHs—benzo(a)pyrene, benzo(b)fluoranthene, and dibenzo(a,h)anthracene were identified with concentrations exceeding their site remedial objectives in the upper three feet of soil. The remedial remedy was complicated due to the large volume of impacted soil, project funding limitations, and the site’s location within a flood plain, preventing the importation of fill to create an engineered barrier. To address these challenges a sustainable design relying on phytoremediation was employed. In an effort to accommodate a short remedial timeframe, a unique approach was selected that was predicated on employing unique phytoremediation agents. The chosen planting regime allowed for maximum root production using rapidly maturing crops where multiple succession crops could be grown during the traditional growing season. The growing season was extended by using cold hardly winter crop, which allowed nearly year-round plant activity. The design and initial implementation was presented in Geo-Chicago 2016: Sustainability, Energy, and Geoenvironment in 2016. This paper summarizes the phytoremediation's operation and monitoring, follow up planting, and soil sampling results.

Linda C. Yang, Matt Catlin, Michael Jordan

Characterization and Ecotoxicological Evaluation of Nanostructured Chitosan Particles

Today there are several areas impacted by contaminants dangerous to the environment and there is a growing need to recover, with the use of materials that generate less environmental impacts. In this environmental line the use of green materials, such as chitosan, an amino polysaccharide derived from a very abundant Chitin and is capable of adsorbing heavy metals and anionic and cationic dyes due to the presence of amino and hydroxyl groups. Another very growing aspect is the new technologies as the nanoparticles can be classified by the structure or size of the material. Therefore, the challenge is to use new technologies and also to know the influence of nanoparticles in the environment. The objective of this work was to characterize the nanostructured chitosan and to evaluate its toxicity. The characterization test is Thermogravimetric Analysis (TGA) and High Resolution Scanning Microscopy (SEM-FEG). To evaluate the toxicity of nanostructured chitosan (green material) magnetized chitosan in different percentages (with iron oxide II, III nanoparticles) and metallic nanoparticles were considered the organisms: Euruca sativa (arugula) and Allivibrio fischeri, using lyophilized bacteria. The results indicated the difference of the structures in relation to the percentage of Chitosan used, being Chitosan 1% with higher magnetic frequency. They also indicated a decrease in growth in samples with magnetic nanoparticles and acute toxicity to Allivibrio fischeri in contact with magnetized chitosan and magnetic nanoparticles.

Fabiana Pereira Coelho, Thaynara Santana Rabelo, Louise da Cruz Felix, Daniele Maia Bila, Elisabeth Ritter

Clean Hydraulic Reclamation Technology and Clean Foundation Treatment Technology—Countermeasures to Contaminated Fills

On basis of amount of collected information on geotechnic features and pollution distribution within reclaimed soils in China, well transportable heavy metal contaminants (both Zn and Ni) within China’s major reclaimed lands were focused herein. Accordingly, both CHRTs and CFTTs proposed by the authors were summarized. To verify the injection and pumping method transformed from the clean pit dewatering method, FDN modeling was done taking stochastic dredge fills within Hengsha Island of Shanghai as the object soils. Numerical analysis results showed the injection and pumping method worked well when acting as a type of CFTT, remediating the stochastic dredge fills and quickening their consolidation simultaneously.

Jianxiu Wang, Linbo Wu, Xuexin Yan, Zhao Wu, Guanhong Long, Hanmei Wang, Na Xu

Nanobioremediation of Soils Contaminated with Lindane: Overview and Research Challenges

γ-hexachlorocyclohexane (γ-HCH, also called γ-BHC and lindane) as a halogenated organic insecticide has become an issue of environmental concern over the years. The isomers of hexachlorocyclohexanes (HCHs) mainly consist of α-HCH, β-HCH, γ-HCH, and δ-HCH. Among these isomers, only γ-HCH has insecticidal applications and thus, leading to cumulative toxic effects through bioaccumulation in food chains. The demand for techniques to decontaminate γ-HCH in soils is gradually growing. The previous studies investigated integrated nanobioremediation techniques involving the use of nanoparticles and indigenous microbes, on the degradation of halogenated organic contaminants, especially lindane, in soils and groundwater. The application of nanomaterials, for instance nanoscale zero-valent iron (nZVI), has recently been researched extensively. However, its efficiency is limited by low aqueous solubility and high hydrophobicity of the contaminants. Moreover, the degradation of contaminants by nanomaterials may not be complete resulting relatively high levels of toxic intermediates. This critical review highlights (i) the applications of nanoparticles for the degradation of γ-HCH (nanoremediation); (ii) the applications of microorganisms for γ-HCH remediation (bioremediation); and (iii) the combination of nanoremediation and bioremediation through the application of nanomaterials and microbes, respectively, in order to achieve effective remediation of γ-HCH (nanobioremediation). Further research on effective biological methods complementing nanoremediation is needed to the development of effective and efficient remediation strategies for recalcitrant halogenated organic contaminants in the subsurface environments.

Liang Zhao, Jyoti K. Chetri, Krishna R. Reddy

Spirodela Polyrhiza: An Efficient Hyperaccumulator of Nickel at Low Concentration

Over a few years of time, heavy metal pollution in surface water has increased manifold owing to large scale dependency upon industrialization and modernization. Therefore, an effective removal of heavy metal pollution is important. Phytoremediation is an eco-friendly and cost-effective method of heavy metal removal by different plant species from water. The process has been utilised in the present investigation to remove Ni from contaminated water by duckweed Spirodela polyrhiza. At three different initial concentrations 2.92, 3.9, and 4.9 mg/L of Ni in contaminated water, removal of Ni by Spirodela polyrhiza has been studied together with their morphological changes. Bio concentration factor for Ni removal was obtained to be greater than 1000 at initial Ni concentrations of 2.92 and 3.9 mg/L, respectively. The results therefore suggest that duckweed Spirodela polyrhiza can efficiently remove as well as uptake Ni from contaminated water with minimal signs of toxicity symptoms.

Chandrima Goswami, Kaushik Bandyopadhyay, Arunabha Majumder

Enhancement of Water Reuse by Treating Wastewater in Constructed Wetlands: Minimization of Nutrients and Fecal Coliform

“CW4Reuse” i.e., Constructed Wetland for Reuse technology, the eco-centric, low-cost approach for the management of domestic wastewaters has been developed at IIT Bombay, Mumbai. The Town of Mhaswad in the State of Maharashtra, India (population 25,000) has been perpetually facing drought to the extent that the livestock suffers death or migration during the summer months. In this study, the performance of the wastewater treatment plant based on ‘CW4Reuse’ technology has been investigated. Raw untreated wastewater polluted the Manganga River till the constructed wetland was commissioned. The treatment plant consists of nine horizontal subsurface flow constructed wetland beds each having dimension of 18 m × 4 m and 0.6 m depth. The constructed wetland beds are vegetated with Canna indica species. The present study investgates the system’s performance with respect to BOD5, COD, TP, TKN as well as fecal coliform. The operating conditions and routines shall be mapped with the corresponding efficiencies of removal of TP, TKN, and fecal coliform with the aim to maximize the removal of nutrients and pathogenicity. Currently, the treatment system is removing 74% COD and 92% of BOD5, while the treatment plant is subject to around 250 mg/L of COD and 100 mg/L BOD5. It is recognized that the community would like to put the treated water for high-end reuse applications including toilet flushing, floor washing, and other body contact applications for vegetables and cash-crop cultivation. Kinetic studies are being conducted in the existing treatment systems by varying different operating conditions to achieve improved performance.

B. Lekshmi, Rahul S. Sutar, Dilip R. Ranade, Yogen J. Parikh, Shyam R. Asolekar

Evaluation of Sodium Adsorption in Clay Soil in the Presence of Crude Oil

Throughout the productive life of an oil field there is usually a simultaneous production of gas, oil, water, and impurities. This formation water which composes the crude oil presents high levels of dissolved salts, being on average three times superior to those of seawater, whose salinity is 35 g L−1. In this perspective, crude oil contaminated soil presents great influence of the salinity requiring studies to determine its comportment, bringing clarity to the interaction between the soil, oil, and salt and the process involved in soil remediation. The soil was sampled in an area of oil extraction on land in the state of Sergipe, northeast of Brazil. For this purpose, stable oil-in-water emulsions were prepared from a heavy oil sample and a light oil sample. The aqueous phase of the emulsions was distributed with different salinities: 0 L−1 to 150 g L−1 sodium chloride. All the emulsions were prepared at 80 °C and rotation speed (Turrax) of 16,000 or 22,000 rpm for 15–20 min. The batch test was used for the determination of soil-contaminant interaction parameters. The assay was performed during the 24 h period in Erlenmeyers of 250 ml containing a 1:10 ratio of soil:emulsions. Chloride, sodium, and electrical conductivity were measured. As a result, it was observed that high contents of NaCl results in desorption of Chloride for sorption tests with saline solution and emulsions. Sorption Tests appointed to higher sorption of sodium on Emulsion Tests (light oil > heavy oil). Tree isotherm models were tested therefore none of them could fit the sorption process observed.

Thaynara Santana Rabelo, Stella Melgaço, Fabiana Pereira Coelho, Daniele Maia Bila, Elisabeth Ritter

Photochemical Oxidation of Complex Organic Contaminants in Water

Various complex organic pollutants resist conventional wastewater treatments. Thus, it is not possible to assure that water and wastewater treatment plants achieve the adequate removal of such organic contaminants, increasing the risk for human health and ecosystems. In this work, we have studied the capacity of the photochemical treatment for the degradation of complex organic pollutants in water. Selected dyes and pesticides were tested for their possible degradation by UV-C light. All the tested compounds were decomposed by the UV-C. The dyes malachite green and indigo carmine were completely degraded in 17 h whereas the tested pesticides (thiamethoxam, pyriproxifen, difenoconazol, and phosmet) were only partially degraded in 8 h. A detailed study with thiamethoxam proved that the UV-C light was able to decompose the molecule in just 15–30 min, and then the degradation products were oxidized with the UV light but at a much slower rate. The chemical oxygen demand showed no or minor removal of organic matter in water, proving that the photochemical oxidation was not able to mineralize the organic compounds.

Santiago Urréjola, Claudio Cameselle, Susana Gouveia, Mercedes Pardo

A Zero Emissions Landfill: Turning Myth to Reality

The ever increasing population has been the root cause for the outburst of solid wastes. Dumping wastes in a pit or an open area had been in practice ever since the advent of civilization. With the growing awareness about the health risks associated with the open dumping of the wastes, landfills gained eminence. Landfills have been modified from simple dumping to the engineered landfills with the liners. Initially, the major concern of a landfill was the pervasive odor which affected the lives of dwellers around the landfill area. As the gases such as methane (CH4) and carbon dioxide (CO2) got recognized as the major contributors of global climate change, the landfill emissions became more critical. Currently, landfills are considered to be the third largest source of CH4 emissions in the United States (US). Various efforts have been made to control the landfill emissions such as providing low permeability landfill covers, installing gas extraction systems, and the biocovers. Landfills used to be considered as a liability due to the emissions and the odor. However, with the gas collection and recovery systems installed, the landfills have been able to generate revenue as well as lower the carbon footprint by converting extracted gas to energy. Modern engineered landfills with the engineered covers and gas extraction systems are able to keep the emissions to the minimum level, however there are fugitive emissions emanating from the landfills and contributing to the global climate change. Recently, in an attempt to capture those fugitive emissions and render landfills emissions free, an alternative landfill cover called biogeochemical cover concept was introduced. The biogeochemical cover aims to remove CO2, hydrogen sulfide (H2S), and CH4. This paper discusses the progressive transformation of landfills into zero emissions landfills.

Jyoti K. Chetri, Krishna R. Reddy

Treatment of Diethyl Phthalate from Municipal Solidwaste Open Dumpsite Through Ozone-Based Advanced Oxidation Process

A high content of organic matter especially the refractory organic matter, ammonia, heavy metals and toxic compounds in the leachate from open municipal solid waste dumping makes the treatment of leachate from open dumps more complex. Leachate generation is a major problem for solid waste landfills and causes significant impact on surface water, groundwater and soil. Leachate sample was collected from open dumpsite for Chennai city during the pre-monsoon period. Due to its non-segregation in nature, it has non-homogeneous chemical composition as well as concentration it is essential to treat the leachate before letting out into drains which ultimately reaches the water bodies. In this paper, synthetic leachate was prepared in accordance with the characteristics of the dumpsite leachate and removal of Diethyl Phthalate (DEP) through Ozone-Based Advanced Oxidation Process (AOP) was investigated and reported. AOP plays a significant role in leachate treatment techniques due to its capability of rapid breakdown of DEP which are resistant to conventional biological or Physico-chemical treatment. Semi-batch studies with O3,O3 + H2O2 were demonstrated and the control parameters are optimized for the leachate treatment. O3,O3 + H2O2 process was performed in the natural pH range and initial experiments were carried out with semi-batch ozone only. The addition of different concentrations of H2O2 leads to increase in pollutant removal and the results are discussed. Various influencing parameters that govern the efficiency of AOP are evaluated and reported. The influence of pH, COD, heavy metals, UVA and intermediate products on the performance of AOP was also studied and efficiency of the process was determined. It is found that Peroxone-based AOP process is an efficient and viable treatment technique for the treatment of leachate from open dumping site of municipal solid waste.

S. Mohan, D. Gokul

Static and Dynamic Leaching Studies on Coal Gangue

In the present study, an attempt has been made to determine the leachability of selected trace metals like As, Cr, Co, Se, Ni, Cu, Zn, Cd, Pb and Mn from coal gangue sourced from an underground and open cast mining area(s) of Bhupalpally Coalfields of Telangana State, India. A standard laboratory leaching test (dynamic in nature) developed for combustion residues has been adopted to study the leachability of these trace elements as a function of liquid to solid ratio and pH. A series of static column leaching tests were also conducted to investigate the leachability of these selected heavy metal ions simulating field conditions. The column tests revealed that heavy metals from coal gangue exhibit greater mobility particularly under acidic conditions. Further, relatively higher concentrations were leached for both static and dynamic leaching conditions at low pH levels and is attributed to the difference in solubility product values of respective metal ion complexes. Among the targeted metal ions, with a metal extraction of 30% and 65%, respectively, As and Se showed highest mobility from both static and dynamic leaching tests.

Mohammed Ashfaq, M. Heera Lal, Arif Ali Baig Moghal

Sustainability of Vertical Barriers for Environmental Containment

Vertical barriers have long been used to control groundwater flow and subsurface contaminant migration from contaminated land sites. Commonly employed vertical barrier types available to owners and designers include those constructed using slurry trenching techniques such as soil-bentonite (SB), and cement-bentonite with slag (slag-CB), in situ soil mixed walls (SMW), as well as driven barriers such as sheet piles. The selection of the appropriate vertical barrier technique depended upon site geology, cost, and regulatory requirements with no consideration of the global environmental impact of the type of vertical barrier chosen in terms of sustainable engineering. In this paper, the sustainability of four commonly deployed vertical barrier techniques is discussed. Using the case study method, the paper evaluates a previously completed project where an SB slurry wall was constructed. Evaluations are described for an environmental sustainability assessment (based on the materials, fuels, and equipment used; transport distances for personnel travel and materials/equipment transport), an economic sustainability assessment (based on the direct and indirect costs), and a social sustainability assessment (based on a survey taken by stakeholders/professionals/experts). The paper closes with findings, conclusions, and recommendations regarding the sustainability of vertical barriers.

Jeffrey C. Evans, Daniel G. Ruffing, Krishna R. Reddy, Girish Kumar, Jyoti K. Chetri

A Study on the Behavior of Pond Ash in Unsaturated Conditions Through WRCC

Pond ash is a residue obtained from the combustion of pulverized coal in Thermal power plants. Out of the total production of pond ash, only a small quantity of ash is utilized and the remaining unutilized pond ash is deposited as a waste material covering several hectares of land. Usefulness of coal (Pond) ash has been explored in various geotechnical and geoenvironmental practices like the construction of ash dyke, road and railway embankment, landfill liners, etc. which requires detailed knowledge of geotechnical and unsaturated behavior of pond ash. The understanding of the engineering behavior of unsaturated soil is totally dependent on the water retention characteristic curve (WRCC) which is a graphical relationship between volumetric water content and soil suction. In this paper, the geotechnical characterization and water retention characteristic curves of pond ash have been studied. WRCC has been drawn experimentally using Fredlund device based upon the pressure plate technique for wetting and drying cycles, both. Further, an investigation was carried out to study WRCC hysteresis of Pond ash. There exists considerable hysteresis in drying and wetting curves of pond ash samples which indicates a significant difference in behavior between drying and wetting phases. The different WRCC models were used to fit the experimental WRCC data. The measured WRCC match satisfactorily with predicted WRCC using Fredlund and Xing equation whereas there is an upward shift in the WRCC curve derived using Van Genuchten equation as compared to experimental WRCC. Since the direct measurement of unsaturated hydraulic conductivity is difficult to obtain in engineering practices, the unsaturated hydraulic conductivity function is predicted using measured WRCC as the input parameter using SEEP/W software. The behavior of pond ash was also compared with the results obtained for natural sand as a reference material.

Sanjay Kumar Singh, Janmeet Singh

Utilization of Bagasse Ash in the Compacted Clay Liner

Landfills are highly engineered waste containment systems, designed to minimize the impact of waste on the environment. In modern landfills, the waste is contained by liner and cover systems. Due to the scarcity of natural clay, the commercially available bentonite is often used in the construction of liners. The bentonite layer generally shrinks during the summer, and therefore, severe cracks are formed; thus, it fails to control the migration of leachate. In the past, various additives have been used to stabilize bentonite. In recent years, studies have been focused on using reactive materials as additives so that they can stabilize bentonite, and also, it can adsorb the heavy metals from the leachates. The sugar industry produces fly ash, known as the bagasse ash, which causes a disposal problem. This bagasse ash is found to be a good absorbent material. Hence, a study was carried out to assess the stabilization of compacted clay liner blended with bagasse ash. Several tests, including consistency limits and hydraulic conductivity tests, have been performed by blending different contents of bagasse ash. From the test results and their analysis, it is observed that 40% of bagasse ash can be mixed with bentonite so that the essential requirements of the liner are maintained.

Dharmil Baldev, Apurv Kumar, Sutesh Tiwari, M. Muthukumar, Sanjay Kumar Shukla

Shear Behaviour of Geosynthetic Clay Liner (GCL) Interfacing with Manufactured Sand

In view of the problems of sand extraction and its harmful impact on coastal erosion, research now focusses on viable alternatives. Manufactured sand (Msand) has become an admissible alternative to be used in concrete instead of river sand. In countries like India, sand mining is illegal, considering the adverse effects it can cause to river basins. Replacement of river sand with Msand as a suitable subgrade or capping material in landfills needs to be investigated. When Geosynthetic Clay Liners (GCL) are used on sloping grounds, interface friction between GCL and the base soil becomes important to ensure bonding and arrest slippage issues. While the interface shear characteristics of natural sand with GCLs are well established in the literature, not many studies are reported on the interface characteristics of GCLs and Msand. This study is an approach towards understanding the interface shear strength parameters of GCLs with manufactured sand and compare them against those of river sand under identical loading conditions. To avoid the effects of morphology, identical gradation of both the sands is used in the tests. This gradation is arithmetic average of grain sizes of both the sands, which is achieved by tweaking with the proportions of different sized grains. Chemical analysis of both the sands is carried out for comparison using X-ray diffraction. A GCL with bentonite sandwiched between a woven geotextile on one side and nonwoven geotextile on the other side is used in the tests. Interfacing surface is a nonwoven geotextile in all the tests. Interface shear tests are carried out on river Sand-GCL and Msand-GCL interfaces to obtain adhesion and interface friction angle of both these interfaces. Further, damage assessment of GCL surface due to interaction with these two different types of sands is carried out using Optical Microscopy and image analysis. Results from these studies provided clear directions towards the replacement of river sand with Msand in landfills in terms of interface friction characteristics and the comparative surficial changes in GCLs with the indentation of sand particles, which can give confidence about sand replacement.

Anjali G. Pillai, Gali Madhavi Latha

Impact on Bentonite Due to the Presence of Various Concentrations of Lead and Copper Solutions

Heavy metals are directly introduced to the environment, groundwater and waterways by means of several industrial activities. Migration of metal from the landfill to the surrounding environment is a serious environmental issue worldwide. A liner is a low permeable material used in the waste disposal sites to prevent the migration of toxic pollutants to contaminate the surrounding atmosphere and groundwater resources. Compacted bentonite is used as a liner material because of its high sorption capacity, low hydraulic conductivity and high swelling capacity. The presence of chemicals in the leachate can shrink the thickness of the diffuse double layer (DDL) and may reduce the effectiveness of the liner by reducing its swelling capacity and increasing hydraulic conductivity. Therefore, in the present study, high swelling bentonite is analysed on the change in their behaviour due to the presence of copper (Cu2+) and lead (Pb2+) solutions. One of the essential behaviours of bentonite is consolidation, which is necessary for investigating the settlement analysis of the liner. The study was conducted to determine the impact of lead (Pb2+) and copper (Cu2+) solutions of different concentrations, on the consolidation behaviour of bentonite. In the existence of lead (Pb2+) and copper (Cu2+) of concentrations of 0, 500 and 1000 mg/L, various consolidation parameters, such as compression index (Cc), coefficient of consolidation (cv), volume change (mv) and time, are required for the completion of 90% of consolidation (t90), which were studied. Result shows that cv increases with an increase in concentration of the heavy metal, whereas Cc, mv and t90 of the bentonite decrease. The study also indicates that the rate of consolidation of the bentonite increases in the presence of copper and lead. The results of this study may deliver a general idea for estimating the liner performance in the presence of different kinds of toxic chemicals existing in the leachate.

Saswati Ray, Anil Kumar Mishra, Ajay S. Kalamdhad

Seismic Response of Bentonite Enhanced Soils to be Used as Fabricated Liner in Engineered Landfills

Earthquakes are one of the most severe natural disasters that are responsible for significant damage to structures causing vertical settlements, lateral spreads and tipping of buildings. Solid waste landfills can also be seriously affected by seismic activity. In landfills, liners of low permeability material are used to arrest the leachate. If the landfills are located in regions of high seismicity, the fabricated liners may be susceptible to damage. Generally, cohesionless soils are considered to be vulnerable to damage caused by earthquakes. Also, evidence of sandy soils with a substantial amount of fines being prone to liquefaction is available in the literature. If cracks develop in the liner, the whole purpose of engineered landfill gets defeated and all the investment incurred towards the landfill would go in vain. This paper aims at understanding the behaviour of landfill liner systems subjected to static and dynamic loading with emphasis laid on ascertaining the effect of adding plastic fines (bentonite) to the cyclic resistance of liquefiable sands and coal ash. The stress-controlled undrained cyclic triaxial tests were carried out at a frequency of 1 Hz and initial effective confining pressure of 150 kPa on soil specimens with 70 mm diameter and 140 mm height. It was observed that pore water pressure generated in sand-bentonite mixes with 10% bentonite is high and slowed down thereafter upon an increase in bentonite content up to 20% in the soil mix resulting in the increased cyclic resistance. The number of cycles required for initial liquefaction were quite less in coal ash, as compared to clean sand. It was found that coal ash is more susceptible to liquefy in comparison to sand.

Jaskiran Sobti, Sanjay Kumar Singh

Interpretation of Hydraulic Conductivity of Bentonites Based on Sedimentation Characteristics

This study suggests a new test method for the interpretation of hydraulic conductivity of GCLs. The proposed methodology is sedimentation test which can be applied after swell index test by vigorously shaking the graduated cylinder. The study basically shows that the bentonites may have the same swell index values, but different hydraulic conductivities. Therefore, swell index may not be a suitable test method for the interpretation of hydraulic conductivity. However, bentonites have different sedimentation characteristics which can be correlated well with the hydraulic conductivity. For example, bentonites serving accumulation type of settling (AS) may have greater hydraulic conductivity than the bentonites serving mixed or flocculated type of settling (i.e., MS and FS).

Esra Dikişçi, El Hassen Abd Moulana, A. Hakan Ören

Effect of Organic Matter on Index Swell Properties of a Conventional and Bentonite–Polymer GCL

Like inorganic salts, organic matter is also a major component of leachate from municipal solid waste (MSW) landfills. This study uses humic substances (HS) to investigate the influence of organic matter on the swell index (SI) and liquid limit (LL), a conventional sodium bentonite (Na–B), and a dry mixture of Na–B and proprietary polymer (B–P), extracted from commercially available geosynthetic clay liners (GCLs). The SI and LL tests were performed using 5–200 mM NaCl and CaCl2 solutions prepared either with or without 100 mg/L HS. Adding 100 mg/L HS to the NaCl solutions resulted in an increase in SI of Na–B for $${\text{Na}}^{ + }$$ concentration ≥20 mM. However, with the $${\text{Ca}}^{2 + }$$ solutions adding HS caused a slight decrease in SI of Na–B at low $${\text{Ca}}^{2 + }$$ concentrations (≤20 mM) but had no effects on the SI of Na–B at $${\text{Ca}}^{2 + }$$ concentrations ≥50 mM. On the other hand, the SI of B–P with $${\text{Na}}^{ + }$$ solutions containing HS was consistently lower than with the pure NaCl solutions. But like the Na-B, HS had no effect on the SI observed for B–P with the $${\text{Ca}}^{2 + }$$ solutions. Within the range of $${\text{Na}}^{ + }$$ and $${\text{Ca}}^{2 + }$$ concentrations used in this study, the addition of 100 mg/L HS did had no significant influence on the LL of Na–B. At similar $${\text{Na}}^{ + }$$ and $${\text{Ca}}^{2 + }$$ concentrations, LL of B–P with solution containing HS was significantly higher than with the pure salt solution. Hydraulic conductivity testing of the GCLs is currently ongoing using test solutions of interest selected based on the results of the SI and LL tests.

Christian Wireko, Tarek Abichou

Chemical Compatibility of Slurry Trench Cutoff Wall Backfills Comprised of SHMP-Amended Ca-Bentonites in Lead-Contaminated Solutions: Hydraulic Conductivity Assessment

Sodium bentonite is the major type of bentonite used for soil–bentonite slurry trench cutoff wall construction. However, application of low swelling calcium bentonite (Ca-bentonite) is extremely meaningful for countries where high-quality sodium bentonite is scarce, while Ca-bentonite is plentiful. This study presented investigation of hydraulic conductivity of soil–bentonite backfill containing sodium hexametaphosphate (SHMP)-amended Ca-bentonite in lead nitrate solution with Pb concentration of 4.8 mM (1000 mg/L). Duplicate flexible-wall hydraulic conductivity tests were conducted using tap water first and followed by the lead nitrate solution. The volume, pH, and electrical conductivity of the inflow and outflow liquids were monitored, and Pb concentrations in the outflow liquid were measured. The variation in hydraulic conductivity with the pore volume of flow of permeant liquid was assessed. The results show that the hydraulic conductivity maintained a value lower than 10–9 m/s in either tap water or Pb solution. The Pb solution had insignificant adverse effects on hydraulic performance of the backfill containing amended bentonite during the tested period.

Yu-Ling Yang, Yan-Jun Du, Krishna R. Reddy, Ri-Dong Fan

Mechanical, Hydraulic, and Chemical Behavior of Steel Slag-Amended Loessical Silt–Bentonite Liners

Liners are engineered layers of low hydraulic conductivity designed to isolate solid, semisolid, or liquid wastes from the environment. Most common materials for liners construction are natural soils amended with bentonite to achieve the low hydraulic conductivity specified by current regulations. This work evaluates the potential reuse of steel slag to improve the performance of landfill liners. We evaluate the effect of adding slag to soil on its mechanical and reactive properties when compacted. Used soil is a loessical silt from the center of Argentina which is frequently used for the construction of bottom liners. The effect of slag content and curing time on the unconfined compression strength of slag–silt mixtures is assessed. Obtained values are incorporated in contaminant transport models to evaluate the transport of metal ions present in leachate through landfill barriers. Results show that the retention of metal ions within a compacted barrier amended with steel slag is mainly associated with the increase of the pH of the barrier material.

Franco M. Francisca, Clara A. Mozejko, Daniel A. Glatstein

Finite Element Analysis and Simulation Test Research of Deformation of Anti-Seepage Wall in Landfill

As the most effective way for municipal solid waste disposal in the world, the anti-seepage treatment of sanitary landfill is one of the important factors to be considered in landfill site selection and construction. In the case of no natural water barrier at the bottom of landfill, the landfill site needs to be taken anti-seepage treatment to prevent landfill leachate from contaminating the surrounding soil and groundwater. At present, the vertical anti-seepage wall constructed with bentonite as the main material is the most common method of the landfill seepage control system. The working environment of anti-seepage wall in landfill site is very complicated. The anti-seepage wall not only bears the gravity produced by landfill and the earth’s pressure caused by surrounding soil, but also interacts with the outer covering soil. Therefore, the research on the deformation and stress distribution of the anti-seepage wall in practical applications is of great significance for the design and construction of landfills.

Guozhong Dai, Jia Zhu, Guicai Shi, Shujin Li

Predicting Gaseous Emissions and Leachate Production in Landfills Using Neural Model

The solid waste management problems in developing countries like India are increasing at a fast pace because of heterogeneous nature of waste used in any remedial solution. This is so because India has not been able to impart segregation efficiently in its waste management logistic. Therefore, the only disposal method that is widely practiced to dispose solid waste is sanitary landfills. Landfills receiving such a huge quantum of waste need to be monitored and studied rigorously as they produce gaseous emissions and leachate. The dispersion or dissolution of these two phases of emissions is polluting the environment and affecting the public health and also the planet health. Therefore, to study the possible scenarios arising in the future from landfill, they are to be fragmented for each imparting factor. The artificial neural networks in this regard can be used to develop an integrated predictive model that can account for all the toxic compounds coming in the form of gas and liquid. This study combines all possible factors affecting landfill working from previous studies and presents a conceptual neural model with variables defined to be included for developing an efficient prediction model.

Sunayana, Arvind Kumar
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