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- Herausgeber: John Wiley & Sons
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- Sprache: Englisch
An expert synthesis of the latest materials and methods with applications for groundwater and wastewater treatment
Materials and Methods for Industrial Wastewater and Groundwater Treatment delivers an up-to-date discussion of the materials and methods being used to address the problem of pollutants in industrial wastewaters and groundwater. The book describes innovative new materials with significant potential to emerge as a next-generation solution in the water treatment space.
Cutting-edge research is synthesized into these novel materials and methods and case studies demonstrate real-world applications of new solutions for water treatment. Readers will also find:
- A thorough introduction to new materials and techniques for treating wastewater and groundwater to remove pollutants
- Comprehensive explorations of the latest research on commercially viable methods for treating wastewater and groundwater
- Case studies highlighting the practical application of novel methods and materials as next-generation solutions for water treatment
Perfect for industrial chemists, environmental and material researchers and supervisors, and consulting and design engineers in wastewater treatment plants, Materials and Methods for Industrial Wastewater and Groundwater Treatment will also benefit design professionals, materials scientists, and environmental engineers with an interest in nanomaterial applications to wastewater treatments.
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Veröffentlichungsjahr: 2024
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Table of Contents
Cover
Table of Contents
Title Page
Copyright Page
Dedication Page
Preface
1 Fundamentals and Importance of Water Quality and Treatment
1.1 Introduction
1.2 Nature and Sources of Conventional Groundwater Contamination
1.3 Emerging Pollutants
1.4 Fundamentals, Properties, and Susceptibility of Water to Contamination
1.5 Physical and Chemical Properties of Water
1.6 Types of Water and Contaminants in Water
1.7 Alkalinity in Groundwater and Surface Water
1.8 Hardness of Ground and Surface Water
1.9 Wastewater and Types of Wastewaters
1.10 Types and Nature of Contamination in Wastewater
1.11 Conclusions
References
2 Ground, Surface Water, and Wastewater Quality Management and Treatment Regulations
2.1 Introduction to Water Conservation and Management
2.2 Importance of Groundwater Management and Protection
2.3 Source Pollutants in Groundwater and Wastewater
2.4 Oxygen‐Demanding Materials
2.5 Eutrophication of Surface Water Sources
2.6 Water Resources Management
2.7 Water Reuse Regulations
2.8 Water Treatment
2.9 Biological Contamination in Wastewater
2.10 Types of Microorganisms and their Environmental Factors
2.11 The Role of Microorganisms in Wastewater Treatment Plants
2.12 Future Prospective and Summary
References
3 Groundwater Contamination and its Treatment Techniques
3.1 Introduction to Groundwater Contamination
3.2 Sources of Groundwater Contamination
3.3 Waste Disposal to Groundwater Sources
3.4 Effects of Groundwater Contamination
3.5 Major Contaminants
3.6 Organic Contaminants in Groundwater
3.7 Radioactive Contaminants in Groundwater
3.8 Groundwater Treatment Technologies
3.9 Organic Contaminant Treatment
3.10 Groundwater Contaminant Uptake Mechanism
3.11 Conclusion and Future Perspectives
References
4 Advances in Desalination Materials and Technologies
4.1 Introduction to Seawater Salinity
4.2 Desalination Process
4.3 Types of Desalination Processes
4.4 Phase Change Technologies
4.5 Solar‐Assisted Desalination Processes
4.6 Desalination by Filtration Processes
4.7 Alternative Desalination Processes
4.8 Future Desalination Technologies
4.9 Case Studies and Examples of Seawater Desalination
4.10 Future of Desalination Technologies
References
5 Functional Materials in Desalination and Wastewater Treatment
5.1 Polymer‐Based Functional Materials such as Water Filters
5.2 Classification and Recent Advancements
5.3 Polyelectrolyte Complexes in Wastewater Treatment and Desalination
5.4 Polyelectrolyte Complexes and Zwitterionic Polymers in Desalination
5.5 Polymer‐Based Coagulants and Flocculants
5.6 Functional Polymers in Organic Matter and Other Secondary Pollutants’ Treatment
5.7 Mechanism of Polymer‐Based Flocculants and Coagulants
5.8 Functionalized Magnetic Nanosorbents
5.9 Future Perspective and Conclusions
References
6 Advanced Catalytic and Biogenic Materials for Water and Wastewater Treatment
6.1 Introduction to Catalytic and Biogenic Materials in Water Treatment
6.2 Catalytic Treatment of DOM in Ground and Wastewater
6.3 Advanced Oxidation Processes (AOPs)
6.4 Evolution of Oxidative, Magnetic, and Photocatalytic Treatment Composite
6.5 Magnetically Metal Oxide Nanophotocatalysts
6.6 POM‐Supported Photocatalysts
6.7 Degradation Mechanism in POM‐Based Photocatalysts
6.8 Photocatalytic Membranes in Water Treatment
6.9 Bio‐Based Treatment Systems
6.10 Biopolymer‐Based Flocculants and Coagulants for Industrial Waste Treatment
6.11 Biopolymer‐Based Filters
6.12 Biopolymer‐Based Gels, Hydrogels, Solvogels, and Aerogels
6.13 Prospects of Biodegradable Polymeric Materials in Water Treatment
6.14 Limitations, Challenges, and Opportunities
6.15 Conclusions
References
7 Ordered Porous and Nanomaterials‐Based Water Treatment Systems
7.1 Introduction to Porous Materials in Water Filtration
7.2 Porous Natural and Synthetic Materials
7.3 Block Copolymers as Ordered Nanoporous Precursors
7.4 Block Copolymer‐Based Membranes for Wastewater Treatment
7.5 Block Copolymer‐Based Membranes for Desalination
7.6 Advanced Porous Materials
7.7 MOFs, COFs, and POPs in Wastewater Treatment
7.8 Ordered Porous Materials in Dye Wastewater Treatment
7.9 Ordered Porous Materials for TrOC Treatment
7.10 Ordered Porous Materials Heavy Metal Adsorption
7.11 Porous Materials in Nuclear Waste Sequestration
7.12 Future Perspective and Conclusions
References
8 Future of Desalination and Wastewater Treatment Technologies
8.1 Demand for Future Water Treatment Technologies
8.2 Smart Tools in Future Water Treatment Technologies
8.3 Advanced Treatment and Innovative Technologies
8.4 Renewable Energies in Water Treatment
8.5 Emerging Desalination Technologies
8.6 Renewable Energy in Desalination
8.7 Commercial Potentials and Challenges of Advanced Water Filtration Systems
8.8 Water Treatment Prospective in 2030 and 2050
8.9 Value Addition in Future Water Treatment Plants
8.10 Conclusions
References
Index
End User License Agreement
List of Tables
Chapter 1
Table 1.1 Physical properties of water in different conditions and their si...
Table 1.2 Different types of hardness in water.
Table 1.3 Nature of chemical constituents in natural groundwater extracted ...
Table 1.4 Maximum permissible limits of different contaminants and paramete...
Chapter 2
Table 2.1 Details of selected legislatures and policy framework enlisted by...
Table 2.2 The list of rules and regulations specifically formulated to regu...
Table 2.3 The main bacterial diseases transmitted through drinking water.
Chapter 3
Table 3.1 List of various contaminants and their origin and severity which ...
Table 3.2 Inorganic pollutants presented in groundwater.
Table 3.3 List of organic contaminants and their detailed description and p...
Table 3.4 Types of reactive sources and their potential treatment technique...
Table 3.5 Summary of different conventional and advanced remediation method...
Chapter 4
Table 4.1 The broad list of desalination technologies or processes that are...
Table 4.2 List of top 10 desalination plants across the world generating fr...
Chapter 5
Table 5.1 Common cationic and anionic groups in zwitterionic polymers. Stru...
Chapter 6
Table 6.1 A list of biopolymers originating from various sources and their ...
List of Illustrations
Chapter 1
Figure 1.1 Schematic representation of different sources of groundwater cont...
Figure 1.2 Schematic representation of origin of emerging pollutants, transp...
Figure 1.3 Illustration of water molecules in different states and their inf...
Figure 1.4 List of different bacterial contaminations commonly found in vari...
Chapter 2
Figure 2.1 General schematic of water life cycle in a typical sourcing, usag...
Figure 2.2 Different sources of phosphate and phosphorus in various natural ...
Figure 2.3 Historically known multilayer charcoal/sand filter bed and cloth ...
Figure 2.4 Advanced water treatment techniques used in domestic water treatm...
Figure 2.5 Hierarchical representation of traditional and modern approaches ...
Figure 2.6 Schematics of different steps involved in water treatment/filtrat...
Figure 2.7 Different steps involving (i) primary, (ii) secondary and (iii) a...
Figure 2.8 Ecological footprint and bacterial activities in the environment,...
Figure 2.9 Details of biological entities enlisted by scientists in various ...
Figure 2.10 Size dependency of different waterborne contaminants, which pote...
Figure 2.11 Schematic diagram representing different sizes, shapes, and stru...
Chapter 3
Figure 3.1 Schematic diagram showing various sources of surface water contam...
Figure 3.2 Several contaminants that seep into groundwater through soil or m...
Figure 3.3 Various sources of contaminants that enter groundwater reservoirs...
Figure 3.4 Liquid hazardous waste and solid residual hazardous waste generat...
Figure 3.5 Infographic showing geologic arsenic redistribution cycle in whic...
Figure 3.6 Different types of adsorbents available in the market or in devel...
Figure 3.7 Schematic representation of pump and treat methods followed for t...
Figure 3.8 Schematic representation of air sparging treatment technique used...
Figure 3.9 Schematic diagram illustrating the presence of permeable reactive...
Figure 3.10 Schematic representation of various types of adsorption mechanis...
Chapter 4
Figure 4.1 Classification of different desalination technologies available i...
Figure 4.2 A schematic diagram showing different thermal desalination techno...
Figure 4.3 A schematic diagram showing different solar‐assisted thermal desa...
Figure 4.4 Schematic diagram of bubble column dehumidifiers used as an advan...
Figure 4.5 (a) Working principle of reverse osmosis processes widely used fo...
Figure 4.6 Schematic representation of forward osmosis (FO) seawater desalin...
Figure 4.7 Schematic diagram and working of membrane distillation process us...
Figure 4.8 Schematic representation of electrodialysis working set‐up and it...
Figure 4.9 Working and structural depiction of electrodialysis reversal proc...
Figure 4.10 Schematic representation of carrier gas extraction process.
Figure 4.11 Schematics of working of dynamic vapor recompression desalinatio...
Figure 4.12 Schematic representation of freeze crystallization desalination ...
Figure 4.13 Schematic representation of cages of different forms of Clathrat...
Chapter 5
Figure 5.1 Broader classification and materials properties of advanced funct...
Figure 5.2 Schematic description of various types of functional materials th...
Figure 5.3 Chemical structures of important antifouling zwitterionic materia...
Figure 5.4 Schematical representation of polymer used wastewater treatment f...
Figure 5.5 Schematical representation of cationic polymer electrolyte (CPE) ...
Figure 5.6 The process of coagulation and flocculation involving various typ...
Chapter 6
Figure 6.1 (a) Oxidant consumption profile in various water solutes (DOMs) a...
Figure 6.2 Among various preparation strategies, illustration shows the diff...
Figure 6.3 (a) Schematic representation of photocatalytic pollutant degradat...
Figure 6.4 Schematic representation of catalytically active nanoparticles im...
Figure 6.5 (a) List of polysaccharide‐based natural polymers and their origi...
Chapter 7
Figure 7.1 The illustration of various clay‐based materials having different...
Figure 7.2 (a) Schematic representation of various types of block copolymer ...
Figure 7.3 Schematic showing general synthetic route of mesoporous materials...
Chapter 8
Figure 8.1 A typical remote‐accessed water management system using smart and...
Guide
Cover Page
Table of Contents
Title Page
Copyright Page
Dedication Page
Preface
Begin Reading
Index
WILEY END USER LICENSE AGREEMENT
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Materials and Methods for Industrial Wastewater and Groundwater Treatment
S. K. Nataraj
Jain UniversityBangalore, India
Copyright © 2024 by John Wiley & Sons, Inc. All rights reserved, including rights for text and data mining and training of artificial intelligence technologies or similar technologies.
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Dedicated to FamilyAshwini‐Anvita‐Vrishank
Parents: Veeramma‐Sharanappa
Preface
The Sustainable Development Goals (SDGs) set to achieve by 2030 have been adopted by United Nations with the consent of membrane states has brought back water‐related issues to forefront. Water quality and sanitation (Goal 6) has been one of the main focus under SDGs, which is closely intertwined with other goals such as poverty; health; sustainable cities and communities; responsible consumption and production, heath, poverty reduction, and ecosystems and sustainable consumption and production; life below water, and life on land (Goals 1, 3, 11, 12, 14, and 15). These goals recognize a vial links between water resources, accessibility, quality, and key socioeconomic factors associated with sustainable environmental and development.
On the other hand, increasing industrial manufacturing pursuits, economical activities, rapid urbanization and depleting freshwater sources due to which world is concerned on impending water scarcity. In the last two decades, freshwater consumption on a global scale has doubled that of population growth. This drastic water consumption pattern have reached across communities, societies, and larger geographical locations. This extended water consumption not restricted to limited sectors or region are unsustainable. Thus, the drastic increase in water consumption has disrupted the traditional water demand and supply patterns thereby arise of uncertain future. However, immediate measures may intervene in the escalating situation and may change for good in a long run. Nevertheless, as of today, water consumption is increasing and demand for freshwater driven in population growth and urbanization where the higher per capita water consumption in growing, domestic, and industrial and/or socio‐economic activities across the sectors.
In addition to this, poor water resource management policies, governance and inefficient implementation/development practices, unorganized as well as unscientific agriculture activities, and lack of water recycling efforts are also likely to diminish both quality and quantity of water supplies across the globe. While industries continue to produce and discharge wastewater as well as ground water level expected to deplete, which leads developing countries to experience more acute and pervasive water insecurity. It is also expected that some developed countries will also face strains on their water resources and supply chain. If this continues, regions and countries with poor water resource management policies are unlikely to prepare for future situation in which addressing water‐related challenges might face collective challenges, including poor economic growth, growing inequality, less economical activities, poverty, deteriorating health and sensitization infrastructure, greater risk of disease, and risk of internal political instability.
World witnesses addition of 2–2.5 billion people to current population count by 2050. This will add up to the stress on food production, power generation, and water supplies. The efficient management of these interconnected nexus between water, energy, and food mainly depends on the water managers. Per capita water consumption across the globe considerably varies, in developed regions it is estimated to an average value of ~200 L per person per day. However, on an average, water requirement for human basic needs is estimated ~50 L per person per day at a global level. However, there has been a substantial reduction in water consumption recorded due to promising innovations and technologies adopted in developed countries in sectors like agriculture, domestic usage, municipal consumption, power generation, and so on. However, at larger global level, present water usage patterns do not reflect the sustainability in the face of increasing population growth and climate change scares.
On the other hand, by now, major freshwater source of water has been exploited and water that has been consumed is laying in the form of wastewater in treatment plants, discharge ponds, disposal zones, or in the open environment. Even though there have been efforts to recycle reusable quality of water, however, efforts are limited. It is estimated that at global level, an average of ~15% of wastewater is being recycled immediately after their utilization. At the same time, advanced techniques are being rapidly developed to improve water security through establishing long‐term infrastructure construction for both desalination and/or wastewater treatment targeting various sectors and capacities. These efforts are also being made to minimize the energy consumption and impact on environments. Therefore, shifts have been made toward design and development of energy efficient, economical, high‐performing desalination, and wastewater treatment technologies using cleaner energy such as solar‐assisted, biofuels, wind, and nuclear energy that can significantly address increasing demand for portable water and generation of reusable quality freshwater from wastewater sources. Therefore, seawater desalination and water recycling from waste sources are increasingly becoming major issues for water managers and priority policy issue for governments at the international level.
In addition to this, today world is better positioned to address emerging crisis than ever. Today we have vast information, the knowledge, innovation that is taking place, the technologies that are being developed, and the economic prosperity that can be a vital resources to create infrastructure to manage existing water resources as well as impending water crisis much more efficiently and effectively than ever. The enormous scientific research undertaken across the sectors at global level ensuring systematic understanding of water crisis and measures suitable to address them which is continuously adding to our information/knowledge, new findings, and tools.
In this context, present book provides detailed account of various policies, guidelines and norms framed for water management and usage from various agencies and government across the world. Sections of the chapters also discuss in detail the recent advances that are taking place at global level to design, develop, and implement the global water resource monitoring information system to obtain and distribute the information needed for efficient water management. Also, various regulatory norms followed for various contaminants and their presence in various sources have been discussed in detail to provide a wider spectrum of information. These sections include the specific norms and guidelines for dangerous conventional as well as emerging pollutants that potentially cause serious threat to treatment techniques. For this purpose, various reports, public documents, publications, case studies, monitoring data, and national and international guideline documents on both water quality and treatment guidelines using appropriate technologies have been discussed. On the technologies front, timely, comprehensive, and forward‐looking detailed information on various advanced technologies that involve for desalination are mainly phase change technologies including thermal desalination (humidification/dehumidification, solar chimney, multistate flash distillation, multi‐effect distillation, vapor compressed distillation, electrodialysis, reverse osmosis, nanofiltration, forward osmosis, electrodialysis, electrodialysis reversal and electro‐osmosis, functional polymers, magnetic materials, and various functional nanomaterials, whereas wastewater treatment processes involve physical treatment techniques (screening, grit separation, floatation, filtration, and so on), chemical treatment methods (advanced oxidation/reduction, ion‐exchange, photocatalysis), and biological treatment technique (aerobic and anaerobic, biological filtration) processes, physico‐chemical techniques like granular‐activated carbon (GAC) adsorption and absorption, advanced membrane‐based separation processes like forward osmosis, capacitive deionization, advanced ion‐exchange methods precipitation, coagulation, flocculation, multi‐flash distillation processes, and so on, which have been discussed in detail.
Nonetheless, even in the presence of advanced technologies, water resources will continue to experience newer challenges which will directly affect the environmental sustainability at large. These challenges include (i) increasing water scarcity, (ii) vulnerability to pollution and contamination, (iii) degrading ecosystem, (iv) deforestation, (v) continuing urbanization, (vi) excessive use of agricultural chemicals, (vii) disturbance to biodiversity, (viii) intense droughts and shifts in precipitation patterns, (ix) rising sea levels, (x) looming climate change impacts, etc. Nevertheless, collective efforts and innovative strategies can provide futuristic solution to achieve water and environmental sustainability. Some of these may include (i) integrated water resource management, (ii) watershed management, (iii) conservation and restoration of ecosystems, (iv) adaptation to climate change (v) sustainable agriculture, (vi) promotion of green infrastructure, (vii) educational outreach, and so on. This book is a small contribution toward understanding some of the aspects made in the field of water treatment and wastewater recycling mentioned here. In addition to giving detailed accounts of recent advances in materials development and process designs aiming water treatment and wastewater treatment, this book hope to raise awareness among young and next generation regarding the crucial aspects of conserving natural water resources, safeguarding groundwater, minimizing water consumption, recycling used water, discharge of wastewater and environmental sustainability. Educating individuals, researchers, and managers in the water sectors on recent advances and innovations in materials and technologies in water sector empowers to make informed choices about water use, wastewater disposal, and overall sustainable living practices.
Finally, I would like to take this opportunity to thank Wiley & Team for giving me an opportunity to publish this book. Special thanks to Ms. Summers Scholl, Executive Editor, and Ms. Kubra Ameen, Managing Editor, at Wiley for coordinating throughout the drafting of this manuscript. I also thank my team of research scholars at Sustainable Materials and Processes Lab, Centre for Nano and Material Sciences, Jain University for their constant queries which contributed to the betterment of the manuscript. Also, my sincere thanks to my family, especially my wife Ashwini Nataraj and my children Anvita Nataraj and Vrishank Nataraj for sacrificing their time and allowing me to work on this book without disturbance. My parents (Veeramma, Sharanappa), in‐laws (Yashodha, Mallikarjun), and brothers (Girish, Santosh, and Harish) for providing me with the right atmosphere and encouragements.
S. K. Nataraj
Kadakolla‐Bengaluru
1Fundamentals and Importance of Water Quality and Treatment
1.1 Introduction
Water is an essential natural resource and vital commodity, yet its importance and value are understated. Water is essential for life on earth and without access to safe and clean water, flora and fauna do not survive. On the other hand, contaminated and unsafe water leads to diseases and illness. Safe and adequate quantities of drinking water in humans and animals help regulate body temperature; safeguard body organs and tissues; and keep body tissues like eyes, nose, and mouth tissues in a moistened state. Water acts as a carrier of nutrients and oxygen to different parts of the body and cells. The adequate presence of water in living beings lubricates joints, water helps in keeping of kidneys and liver healthy by flushing out waste products regularly, and so on. Water, being a universal solvent and its ability to dissolve a wide range of vitamins, nutrients, substances, and minerals, acts as a medium through which all essentials are transported in the bodies of living beings and organisms. Water also plays an important role in regulating and facilitating work of biomolecules and macromolecules like enzymes and proteins in living organisms. Generally, an average human body is composed of about 60% water. Therefore, water acts as a multifunctional and multitasking facility essential to transport and regulate bodily fluids that help in food digestion, nutrient absorption, bodily fluid circulation, creation of saliva, transportation and distribution of nutrients, and maintenance and regulation of body temperature [1–3].
In the larger context, the health of large water bodies such as lakes, rivers, seas, and oceans can affect the weather of an area and climate of a region. Water has unique physico‐chemical properties like heating and cooling more slowly than land masses which regulate maintaining atmospheric as well as climatic conditions of a region. For instance, due to the temperature regulatory properties of water, the coastal regions maintain cooler temperatures in summer and warmer in winter. Thus, physico‐chemical properties of water help in creating more moderate weather and climatic conditions maintaining narrower temperature ranges. On the other hand, changes in temperature due to climate change in many areas increase the water temperature which causes eutrophication and excessive algal growth, which directly deteriorates the drinking water quality. Further, recent decades have seen increased industrial activities, high water consumption, and environmental irregularities in treating and managing water resources that are now showing extreme weather events directly affecting the natural resources. Cumulative effects of pollution, extreme weather events, and ever‐increasing water consumption make water more scarce, unpredictable, polluted, unsafe, inaccessible, or all of these. In addition to this, the contaminants and pollutants in the water cycle impact life and environment throughout, which, in turn, threatens biodiversity, sustainable development, and access to water and sanitation. Nonetheless, continued climate change is disrupting weather patterns, leading to unpredictable and extreme weather events, thereby reducing the limited access to water, aggravating water scarcity and contaminating all natural resources and supplies. Similarly, limited freshwater and drought situations can worsen the effluent concentration runoff, chemical composition, COD, BOD, and pH of surface water [4–6].
On the other hand, a large population worldwide draws groundwater for domestic as well as drinking purposes. Generally, ground water sources have been perceived to be safe for domestic and drinking purposes. However, the quality of drinking water extracted from groundwater sources is now being increasingly compromised by elevated concentrations of fertilizer components, sediments, minerals, nutrients, and emerging chemical substances due to increased pollution and extreme storm events. Also, the excessive use of synthetic substances like fertilizers for agricultural purposes enters soil sub‐layers and ultimately reaches groundwater sources. This type of water pollution through human, industrial, and agricultural activities leaves a series of man‐made toxic substances, chemicals, and/or by‐products into groundwater sources. Therefore, this leads to inducing toxicity to the groundwater. Also, the presence of multiple substances creates a series of intermediates and unknown substances with hazardous consequences [7]. Among many side effects, water pollution is known to induce imbalance in the water cycle, which leads to the alteration of weather patterns that may substantially contribute further to global warming activities or severe environmental deterioration at large. Therefore, it is important to devise, design, and implement water quality monitoring, treatment, reuse, and management strategies to cater future water demand. This will also help in documenting patterns of water contamination, surveillance source monitoring, and nature of contamination, which can effectively guide future water resources, and their protection, safety, and management [8].
Modern manufacturing techniques use complex and hazardous raw materials to produce large quantities of commodities. Also, large quantities of freshwater are being drawn from natural resources, most of which end up as wastewater at the end of the product recovery. In this situation, advanced water quality monitoring, treatment, and management play a vital role in ensuring drinking water quality for their safety for human consumption. Similarly, maintaining surface water quality is essential for wildlife and marine life. Among many parameters, pH, temperature, conductivity, dissolved oxygen (DO), total dissolved solids (TDS), chemical oxygen demand (COD), biological oxygen demand (BOD), suspended sediment (SS), metals, nutrients, hydrocarbons, synthetic substances, and industrial chemicals are the main indicators that determine water quality. In a larger context, direct discharge of wastewater into the environment and retaining it in reservoirs in the long term leads to rapid deterioration of ecosystems and environment at large. Therefore, it is important to monitor and determine water quality to understand environmental impacts. These strategies also help in generating, evaluating, and forming policies on environmental water quality that aim to provide the safeguarding mechanisms to protect water bodies, natural water resources, and freshwater reservoirs in the environment against the adverse chemical and biological effects through multiple chemical and biological contamination arising from anthropogenic, agricultural, and industrial diffuse emissions at the point sources as well as their reservoirs [9–12].
In this direction, worldwide efforts are being made to safeguard water quality and environmental health. As water is essential for life on earth, it is obligatory for every state and national governments to take appropriate measures within their authority to formulate and implement norms and regulations to ensure sustainable water resource management. The United Nations (UN) has long been advocating regulating sustainable utilization of resources, in particular water as essential for everyone. World regulatory bodies have recognized the right of every human being to have access to enough water (50 and 100 L) for personal and domestic uses per person per day. In this regard, the UN, through its several programs and initiatives, has emphasized addressing the global water crisis caused mainly due to lack of quality water to meet industrial, agricultural, and human needs. Accordingly, the World Water Development Report (2021) on “Valuing Water” evaluates the status and challenges in valuing water across different sectors. This report also gives wider perspectives and identifies ways and means in which valuation can be promoted as a method and tool to help achieve sustainability [13].
More importantly, in 2015, under the umbrella of the UN, world leaders agreed to focus on 17 global goals concerning each nation and every human being. Accordingly, the United Nations Sustainable Development Group (UNSDG) a consortium of 36 UN departments, funds, programs, specialized agencies, and offices conglomerate to play a role in sustainable global development. Among 17 UNSDGs, Sustainable Development Goal‐6 (SDG‐6) is to “ensure availability and sustainable management of water and sanitation for all.” This goal further aims to achieve universal and equitable access to safe and affordable drinking water for all by 2030. In the sanitation section, it aims to achieve access to adequate and equitable sanitation and hygiene for all by 2030 and end open defecation, paying special attention to the needs of women. In the larger context, UNSG's 6th targets cover both water cycle and sanitation in all aspects and their achievement is designed in regular intervals. Further, access to safe and/or healthy drinking water is defined as the major percentage of the population having access to affordable drinking water with improved and clean sources. On the other hand, with increased stress on water resources to sustain an ever‐growing population, increased demand from the irrigation sector, industrial supplies, and other needs causing water is increasingly causing scarcity to this essential commodity [14].
Today, due to dire water scarcity, the world needs revolutionary and transformative methods to conserve existing water resources and treat wasted or used contaminated water sources. Even though major portions of natural streams untouched by human activities have maintained good quality, increased human and industrial activities have contaminated several sources of groundwater to a greater extent [15]. Groundwater contamination mainly occurs through a series of regular human activities. Recent times have witnessed increased industrial activities which resulted in the release of humongous amounts of contaminated water to unregulated reservoirs which led to the seeping of toxic as well as hazardous contaminants into groundwater streams. Among many contaminants, groundwater resources are mainly characterized by the presence of man‐made products like synthetic substances or chemicals, oil contamination, gasoline, and so on. Major source of ground contamination is from the materials diffused through the land's surface to make soil contamination at first and further end up in the groundwater. Nevertheless, groundwater is mainly characterized by three types of contaminants generally categorized as synthetic chemicals, sediment, and fecal coliform. In addition to human activities, natural influences like soil types and their compositions also play a role in groundwater contamination. This makes the overall process complex as the different chemicals in soil react differently and may transform in a variety of forms in soil, thereby in groundwater upon reaching the reservoirs. Among these major categories, the significantly farming chemicals, storage tanks, septic waste, landfills, uncontrolled hazardous waste, and atmospheric pollutants contribute majorly [16–18].
On the other hand, groundwater contamination can result in lack of quality water, loss of good quality water supply, degradation of surface water system, poor drinking water quality, high cleanup costs, high costs for alternative water supplies, and risk to human and animal health upon consumption. This situation also forces the water management and policymakers to drastically reduce water withdrawals, and consumption and devising suitable water treatment technology for eliminating hazardous chemicals from contaminated groundwater. However, recent studies have concentrated on documenting detrimental effects and new classes of substances that are known as emerging pollutants (EPs). With this, there have been several efforts in recent times that enlisted several petroleum‐based organic compounds, plastics, and fuels, and recommended a series of measures and guidelines to extract, use, and dispose after use. Also, the studies have emphasized the fundamental understanding of water treatment processes, training human resources to handle impending crises, and understanding the basics of wastewater treatment and its usage parameters in advanced water treatment techniques like advanced oxidation process, membrane‐based separation processes, the activated sludge process, advanced activated sludge treatment process, advanced aeration techniques, biological nitrogen removal, and so on. Advanced water treatment technologies have been increasingly used in processes that are capable of drastically reducing or eliminating specific contaminants from groundwater or wastewater that are normally not achieved through conventional treatment techniques. In case of groundwater contamination, the level of impurities will be at a trace level that may require sensitive as well as advanced analytical tools [19, 20].
The quality of groundwater is mainly determined by its natural, human, and industrial influences. In the absence of human and industrial influences, groundwater quality would be determined by the nature of bedrock minerals, deposits of minerals, atmospheric influences like evapotranspiration, and the nature of dust and salt by wind. Further, the nature of leaching of mineral deposits, salts, organic matter, and soil nutrients due to the hydrological factors into groundwater can alter the physical, chemical, physico‐chemical, and biological composition of water. On the other hand, typically contaminated water quality is estimated and determined following a comparative evaluation of physical, chemical, and biological characteristics of a water sample in alignment with water quality guidelines or global standards. Interestingly, modern drinking water safety and quality guidelines and standards are formulated to enable the enforcement of the provisions of clean, safe, and healthy water for human consumption that helps improve human health. These guidelines and standards are designed based on scientific rationale methodologies acceptable across the spectrum. These globally acceptable norms are guided by regulations and universal standards issued by global organizations like the World Health Organization (WHO) [21]. Even though many developed countries follow their own specific standards in addition to international norms to be applied in their sovereign country. For instance, European nations follow the European Drinking Water Directive and the United States follow the United States Environmental Protection Agency’s (EPA’s) standards that have a series of norms and guidelines through their Safe Drinking Water Act [22]. Similarly, China formulated its own drinking water standard GB3838‐2002 (Type II) issued by the Chinese Ministry of Environmental Protection in 2002. On the other hand, the Indian Standard was adopted by the Bureau of Indian Standards for determining the quality of drinking water for identification, collection, and distribution [23]. On the other hand, those countries without legislative or administrative norms and frameworks for safe water standards and the global standards issued by the WHO design and publish international guidelines to be followed in comparison to other countries [24].
1.2 Nature and Sources of Conventional Groundwater Contamination
Water has been considered an essential commodity around the globe. Water in its safe and clean state is used for domestic purposes such as washing, drinking, cooking, irrigation, industries for the purpose of cooling machines, and raw material solvents among many others. Water supports all aspects of life from drinking, cooking, washing, cleaning, and other human activities. Even though a major portion of the earth is covered with water, unfortunately, there is a limited amount of freshwater (<3%) that can be utilized for human consumption and domestic purposes. In this situation, increased pollution is inducing deep freshwater stress that is accessible for the daily life of millions of people. On the other hand, increased exposure of freshwater resources like wells, ponds, lakes, rivers, and streams to a series of emerging contaminants renders them unsafe, hazardous, and unusable. Among many trillions of liters of water available on earth, two‐thirds is stored and isolated in glaciers and ice caps and merely less than 3% is freshwater available for consumption. Interestingly, water can be a renewable resource. However, overuse and lack of efficient management or contamination with a series of pollutants reduces the quality and quantity of freshwater resources. This led to water scarcity, and recent estimates suggest that more than 2 billion people around the world lack access to sufficient quantity of safe and clean water [25–27].
Nevertheless, groundwater is a major source of freshwater resources for the global population. Groundwater has been extracted throughout the world for domestic, industrial, and agricultural uses. However, nearly one‐third of the world’s population depends on groundwater for drinking and domestic purposes [28]. Most of the developing countries with large arid and semi‐arid regions solely depend on sources of groundwater and limited surface water sources. Nevertheless, major arid and semi‐arid regions only find a secured supply of groundwater for drinking and domestic purposes through sustainable means. However, ever‐increasing urbanization, modernized agricultural practices, rigorous industrial activities, and looming climate change are posing significant threats to surface quality of surface as well as groundwater sources. Among many contaminants, toxic metals, organics, hydrocarbons, trace heavy metal contaminants, microplastics, pesticides, nanoparticles, and other emerging contaminants are posing serious threats to human health, ecological systems, and the environment at large, which directly affect the sustainable socio‐economic development [29–32].
The recent past has seen increased use of synthetic substances and millions of chemical compounds. This has led to the contamination of several natural resources significantly, which has shown increased threat in the past three decades. Chemical contamination in groundwater has reached alarming levels due to prior mentioned reasons. While increasing contamination of groundwater poses a serious challenge to human populations, which requires greater attention from researchers, innovators, technologists, industrial partners, decision‐makers, and policymakers to formulate strategies and programs to protect both the quality and quantity of water resources.
Groundwater contamination is defined as the intentional or accidental inclusion or addition of undesirable and unwanted substances to groundwater due to human, agricultural, and industrial activities. In a broader definition, the most commonly occurring contaminants in groundwater can be categorized into three types, namely chemical, sediment, and fecal coliform. Other than direct addition of substances, type of soil and landfills, and nature of waste dump yards play a role in groundwater contamination. Other vital source materials that enter into water resources that turn into a contaminant in groundwater can be sub‐categorized into farming chemicals (fertilizers, insecticides, pesticides, additives, and so on); septic waste from domestic households and industrial outlets; landfills originated from various sources; uncontrolled domestic, industrial, and agriculture hazardous waste; waste storage tanks and reservoirs; and atmospheric pollutants. Further, residues that originate during agricultural activities, spreading of nutrient slurry; diffusion of excessive fertilizers, insecticides, pesticides, fungicides, herbicides, and human and animal waste, or discharges on the land that can turn into pollutants. Release of such domestic and animal waste is generally characterized by high concentrations of substances such as nitrates, phosphates, organics, and pathogenic contamination such as viruses, bacteria, and fungi, which seep into underground water sources over a period of time. These situations create an aggravated situation when the soil facilitates the spreading and diffusion of excessive synthetic as well as natural through their favorable interaction with different types of soil. For instance, sandy soils facilitate the spreading and diffusion of pollutants much faster than clay soils do. This leads to diffusion of fertilizers, chemical additives, viruses, bacteria, road salt, medications, and fuel. On the other hand, many of the pollutants in groundwater originated from geogenic origins as a result of dissolution of the natural mineral deposits over the period of time within the Earth’s crust under the influence of excessive runoff or flood irrigation as shown schematically in Figure 1.1 [33–35].
Figure 1.1 Schematic representation of different sources of groundwater contaminants originating from various sources like waste landfills, domestic wastewater, leakage from domestic septic tanks, diffusion of mineral deposits from earth’s crust, and so on.
On the other hand, hardness in water can be traced to percolation of limestone, chalk, or gypsum deposits that are largely composed of calcium, magnesium carbonates, bicarbonates, and sulfates. Among many low‐solubility minerals, less to medium hardness can be characterized when the concentration of calcium carbonate is quantified near 150 mg/L. However, continued pollution due to rapid expansion of the global population led to uncontrolled and unregulated urbanization and industrialization, thereby inducing huge stress on agricultural production and the socio‐economic programs. This is also posing serious challenges and contaminants have been known to induce negative impacts on natural resources due to their anthropogenic origin. Even though global policymakers and resource managers have devised a series of norms and regulations to tackle the issues associated with water pollution, the most severely affected population of resource pollution mainly belongs to those rapidly growing economies and middle‐income countries. Therefore, it is important to document and design futuristic resource management guidelines considering the fate and consequences of natural resources in particular ground and surface contamination which directly affect living beings [36–39].
1.3 Emerging Pollutants
Modern definition of water pollutants and the nature of pollution is slowly and steadily shifting with the change in the nature of the contaminants and their properties. Futuristic pollutants have been now expanded with the inclusion of a broader list of substances, chemicals, and matters that are widely used in day‐to‐day life and have never been earlier considered a threat to humans or living beings or environment at large. Conventional pollutants or contaminants have been broadly categorized into physical, chemical, and biological contaminants. Conventional chemical and biological contaminants have been broadly identified with known side effects, toxicity, and end‐use consequences. Among these biological contaminants such as pathogenic family, bacteria, and parasites have been known to induce serious health risks to humanity that date back to recorded civilization. Conventional pollutants have been well studied in the past for their origin, nature, properties, toxicity, and metabolic effects upon consumption by humans and living beings. However, a new set of findings reveals that the intermediary and transformative forms of conventional pollutants in water for a long period of time induce completely different properties and potential toxicity to water bodies and resources. This is causing a lot of anxiety and worries among researchers. The conventional pollutants transform into new intermediates with unknown physical, chemical, and physico‐chemical properties. These unknown sets of offspring from the conventional pollutants have caused a serious threat to every possible water resource. Therefore, conventional pollutants and contaminants in their new outlook have raised a global concern [40].
Globally, today the most prevailing and prevalent problem water resources face in maintaining their quality, health, and usability is eutrophication. Eutrophication occurs as a result of high concentrations of nutrient loads such as phosphorus and nitrogen, which significantly impairs quality of water, thereby restricting direct use and health of water [4]. Natural eutrophication is a slow process that occurs as a result of accumulation of nutrients in lakes or other bodies of water. In this natural process, an increased concentration of nutrients feeds excessive algae growth which leads to unsightly scum on the surface of water, low penetration of light, and obstruction of air circulation, which decreases recreational value of water, which results in clogging of the water supply system. Eutrophication is increasingly considered a serious environmental threat in aquatic ecosystems since it often results in the degradation and deterioration of water resource quality and drastically decreases the DO in surface water resources. Once the concentration of dissolved water drastically decreases, eventually the aquatic system turns into a “dead zone” that is incapable of supporting aquatic life, which at large turns unusable. Major algal nutrients such as phosphorus and nitrogen originate mainly from leaked or discharged domestic sewage, which also increases microbial pollution, agricultural runoff, industrial effluents, and increased atmospheric pollution from fossil fuel burning, forest fires, and bush fires. This situation has worsened due to the increased human populations, excessive use and discharge of domestic wastewater, increased industrial activities with limited treatment measures, and agricultural runoffs due to flood irrigation that carries excessive fertilizers. Further, climate change and extreme weather patterns are threatening the natural water cycles and influencing the major alterations to the hydrological cycle [33, 41].
Increasingly, lakes and reservoirs have been exposed to increased amounts of synthetic and discarded materials. This makes them susceptible to the degradation and negative impacts of eutrophication as the complex dynamics of pollutants continuously change in relatively longer periods of time and many of these acts as substrates for relatively smaller pollutants. Among many nutrients, nitrogen concentrations give a broader indication for pollution of water in which an increase of nitrogen beyond 5 mg/L in water often indicates extent of pollution from domestic origin, particularly human and animal waste or fertilizer runoff from agricultural activities. Nevertheless, synthetic fertilizers and domestic sewage contribute to nutrient contaminants that majorly contribute to eutrophication. Overall, eutrophication results in uncontrolled algae growth, which prevents penetration of light in deep water, thereby causing deficiency of DO. The algal bloom also helps in acceleration of excessive water plant growth such as water hyacinth severely affecting reservoir‐holding capacity, aquatic life, and overall ecosystem.
Another category of modern pollutants is termed persistent pollutants (PPs). The PPs, in particular persistent organic pollutants (POPs) are chemicals that endure or persist in the ecosystem or environment bioaccumulation through the food cycle and are known to pose a risk of causing adverse effects on health of living beings and the environment [42]. The POPs, in some cases, are also known as “forever chemicals” that the organic compounds remain in the environment and resist natural degradation through either biological, chemical, or photolytic processes. On the other hand, non‐PPs (NPPs) are compounds that break down quickly in the environment. For instance, pesticides undergo natural degradation under the influence of external or environmental factors. Further, different classes of hazardous pesticides are termed cholinesterase‐inhibiting pesticides that include organophosphates and carbamates. Nevertheless, both persistent pollutants and nonpersistent synthetic compounds and chemicals potentially tend to affect humans due to inherent toxicity immediately or within a few hours of contact. PPs tend to pose highly hazardous and poisonous effects over the long term of their presence in the ecosystem or environment. However, as per present estimation, nonpersistent chemicals like pesticides no longer pose a serious threat degeneration. Nonetheless, today PPs are known as a new class of substances and chemicals of global concern due to their potential toxicity, hazardous in their source, transportation, and use until their persistence in the environment. This is mainly due to their ability to biomagnify and bioaccumulate in ecosystems, and aquatic life which induce significant negative effects on human health and the environment. Today researchers are focusing more on PPs and POPs to study their potential toxicity as there is limited information and data available on their interaction and toxicological impacts on receptors in the environment [43].
On the other hand, new pollutants and EPs represent a new and emerging challenge to global water resource quality with potentially serious threats to humans and living beings’ health, ecosystems, and environment at large. In water stress conditions, the need for good and safe quality water is essential and vital to sustain human well‐being, rural and urban livelihoods, and a healthy environment for sustainable development. The major threat to sustaining good and safe quality water is a new class of EPs that can be understood in a general and broader definition as “any synthetic, man‐made or naturally occurring chemical or any microorganism that is generally not monitored, regulated, and managed in the environment with potentially known, recorded, documented, or suspected adverse ecological and human health effects.”
EPs originate from various anthropogenic sources like domestic households, agricultural activities, and industrial discharges and reach the environment in various forms and varieties as shown schematically in Figure 1.2. The EPs originated from various anthropogenic resources are distributed throughout aquatic ecosystems and environmental matrices on a daily basis. EPs are chemicals and compounds that have not been considered until recently and have been now classified or identified as dangerous to the environment, and human beings and living beings. By definition, these new classes of pollutants are labeled “emerging” due to their rising level of concern linked to an increasingly concerned list of substances that were ignored until now. EPs have been mainly identified as chemicals of a synthetic origin or man‐made sources and may also be derived from a natural source and are increasingly categorized as public health risks that are yet to be established. EPs are generally traced back to their origins from household or domestic wastewater discharges containing surfactants that are enormously found in daily used soaps, shampoos, detergents, pharmaceutical ingredients, desecrated excessive drug molecules, pesticides, herbicides, personal care products, industrial discharges, agriculture runoffs, fertilizers, metals, industrial additives, solvents, industrial waste dumps, or landfills. Many of these man‐made compounds, substances, and synthetic chemicals are used and discharged unregulated continuously into the aquatic resources and environment even in very low quantities on a daily basis. Among many drugs, pharmaceutical ingredients, pesticides, and organic compounds may cause chronic toxicity, disabilities, endocrine disruption, and disorders in humans and aquatic wildlife. Further, due to their long‐term storage or holdings in waste reservoirs or landfills, EPs may develop bacterial pathogen resistance causing catastrophic consequences to the surrounding environment. Nevertheless, recent studies have shown increased interest and have made several attempts for the identification, detection, and analysis of EPs in both conventional concentrations and trace quantities in recent times. On the other hand, there has been great advancement in the development of analytical tools due to the continued synergic efforts by researchers, innovators, and technologists in improving conventional tools and refinement of specific techniques for detection of a wide array of emerging contaminants in aquatic ecosystems, natural resources, wastewater treatment plants, and so on both in terms of quality and quantity on emerging environmental concern and in various environmental components and biological tissues. It is noted that EPs may be mobile, continuously transformative, at the same time persistent in water, soil, solids, sediments, landfills, air, and ecological receptors even at trace concentrations. However, several researchers have engaged in advanced research to gather robust data on their origin, intermediates, transportation, fate, behavior in the environment, and impact on ecological sustainability and human health which are still lacking. Nevertheless, due to lack of data sets, case studies, and risk assessment reports, often risk of EPs cannot be affirmatively stated, which do not exist at present on the ecotoxicological significance [44, 45].
Figure 1.2 Schematic representation of origin of emerging pollutants, transportation of various man‐made and synthetic substances through their excessive use which end up in lakes, reservoirs, and dams as a new class of pollutants.
Another major emerging water quality concern is the impact of a series of excessive pharmaceutical and personal care products such as birth control pills, painkillers, surfactants, dyes, semi‐volatile organic compounds, and antibiotics on aquatic ecosystems. Today very little is known about existence, effects, and risk of EPs in the long term on human health or ecosystems, although few of them have been known to exist in the list of conventional pollutants. For instance, some EPs like drug molecules or pesticides are believed to mimic natural hormones in humans and other living species. However, most of the newly found EPs have been traced natural sources of freshwater such as natural springs, seasonal streams, ponds, dams, rivers, rainfall, and boreholes. Today, there is limited access to freshwater resources available untouched by modern pollutants. But, the majority of population living in arid and semi‐arid areas do not access clean and safe water due to the increased discharge of used water containing substances that are used in day‐to‐day life.
Most of the EPs of biological nature originate from the microbes and some of these biological EPs act as substrates with a conducive atmosphere to sustain and transform the other contaminants like farm pesticides, nutrients from fertilizers, raw sewage, and heavy metals in the water. Through agricultural activities, chemicals like nutrients from synthetic fertilizers, herbicides, and pesticides are washed away into runoff or flood streams, which seep into groundwater sources or join into surface water resources like streams and rivers that flow into ponds, lakes, and dams. Among many toxic substances, pesticides have, for example, severe adverse impacts on both human and environmental health. Some of the EPs like pesticides, herbicides, and insecticides may largely originate from agricultural activities confined to farm zones linked to river flow which carry them to a new class of toxic substances and chemicals downstream. Several reports have already recorded toxicity of pesticides are known to cause adverse human health complications such as cancer, behavioral disorder, mutation issues, reproductive health problems, and hormonal problems. Recent studies have also recorded the traces of pesticide residues in various lake and reservoir samples which are meant to supply freshwater to millions in urban and semi‐urban populations. Therefore, presently most of the medium‐to‐large freshwater lakes and dams throughout the world are vulnerable to low‐to‐high concentrations of EP contamination. Nevertheless, the only way to prevent pollutant contamination in both groundwater and surface water is to regulate the excessive use of synthetic and man‐made substances. Another way is to monitor and track the minimal use of agricultural synthetic nutrients in the form of fertilizers and pesticides. To prevent the entry of EPs, these substances and chemicals should not be applied or used close to water bodies [46–49].
1.4 Fundamentals, Properties, and Susceptibility of Water to Contamination
Water, in particular, showed a high affinity toward ionic compounds and other substances capable of forming through hydrogen bonds interacting with water molecules. Water molecule (H2O) comprises one oxygen atom and two hydrogen atoms in which an oxygen atom is connected with two hydrogen atoms via two covalent bonds as shown schematically in Figure 1.3. Water is a simple inorganic molecule comprising only three atoms. This tasteless, colorless, and odorless substance possesses unique properties which make it a very significant molecule vital to the existence of life on earth. However, the several significant physical, chemical, and physico‐chemical properties make water a unique molecule. This exceptional importance of water molecules can be attributed mainly to their arrangement of atoms in the molecule and the bonds involved. The bond between oxygen and hydrogen is a polar covalent bond having a concentration of the electron density around the oxygen atom which is one of the most electronegative atoms. This specific arrangement in water molecules gives rise to a dipolar character in which the oxygen atom is the negative pole and hydrogen atoms are the positive poles. As a result, dipole character in water molecules enables atoms in water molecules to be connected among themselves by intermolecular forces known as “hydrogen bonds.” On the other hand, hydrogen bonds are relatively strong in nature among intermolecular interactions in which a hydrogen atom from a certain molecule is connected to an electronegative atom such as nitrogen, fluorine, and oxygen of another molecule [50].
Figure 1.3 Illustration of water molecules in different states and their influence on physical, chemical, and physico‐chemical properties of water in dissolution of different water‐soluble substances or contaminants.
Even though hydrogen bonding can exist in many compounds such as NH3 and HF; however, the main difference in hydrogen bonding in water molecule (H2O) and other polar molecules is that each oxygen atom in water can form two hydrogen bonds, which is the same as the number of lone electron pairs on the
