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- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
Invest in Nano-Bioremediation for Wastewater Treatment to explore cutting-edge techniques that combine nanotechnology and bioremediation, equipping you with innovative solutions and expert insights needed to tackle global environmental pollution challenges effectively.
The coupling of nanotechnology and bioremediation techniques holds great promise for addressing environmental pollution and contamination on a global scale. The process of bioremediation uses living organisms, such as bacteria, fungi, or plants, to degrade or detoxify pollutants in the environment. Nanotechnology involves manipulating materials at the nanoscale, typically at the scale of individual atoms and molecules, to create novel properties and functionalities. Today, research is focused on exploring the combined potential of nanomaterials and bioremediation for treating pollutants.
Nano-Bioremediation for Wastewater Treatment will serve as a premier guide for nanotechnology in this field, providing information regarding the various challenges that arise from the coupling of nanotechnology and bioremediation techniques. Since very limited literature is available on this subject, the editors have compiled all the current assays and techniques that provide insights into this topic. This book will also cover different fabrication methods and methods for decorating microbial cells on the surface of nanomaterials, which is a key factor for synthesizing microbial conjugation, as well as prototype designing and integrating developed materials into water purification systems. Unlock the potential of cutting-edge nano-bioremediation techniques for wastewater treatment, with practical applications, expert insights, and sustainable solutions that set you apart in the field.
Audience
Environmental engineers, chemists, biotechnologists, microbiologists, nanotechnologists, environmental consultants, researchers, academics, and policymakers focused on developing and implementing innovative solutions for wastewater treatment and environmental remediation.
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Veröffentlichungsjahr: 2025
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Table of Contents
Cover
Table of Contents
Series Page
Title Page
Copyright Page
Preface
1 Nano-Bioremediation and Scale-Up Techniques for Wastewater Treatment
1.1 Introduction
1.2 Basics of Nanobioremediation
1.3 Basics of Wastewater Treatment Plant
1.4 Secondary Treatment Systems
1.5 Different Matrix for the Microbes and Nano-Conjugate Fabrication
1.6 Factors of Scale-Up of Water Treatment Plant
1.7 Existing Studies on Scale-Up Techniques and Design Principles
1.8 Cost Reduction, Energy Efficiency, and Improved Performance
1.9 Conclusions
References
2 Nanomaterials and Microbial Compatibility: Synergistic and Antagonistic Mechanisms
2.1 Introduction
2.2 Mechanisms of Microbial Interaction with Nanomaterials
2.3 Synergistic Effects of Nanomaterials on Microbial Activities
2.4 Antagonistic Responses: Microbial Tolerance and Resistance
2.5 Impact on Microbial Communities and Ecosystems
2.6 Metal Nanoparticles in Water Treatment
2.7 Future Prospects
2.8 Discussion and Conclusion
References
3 Physical and Chemical Characterization of Microbes and Nanoconjugates
3.1 Introduction to Nano-Bioremediation
3.2 Physical and Chemical Properties of Microbes and Nanoconjugates
3.3 Microscopic Structural Analysis
3.4 Spectroscopic Chemical Analysis
3.5 Characterization Techniques and Their Role in Nano-Bioremediation
3.6 Conclusion
References
4 Microbes and Nanoconjugate-Assisted Removal of Heavy Metals from Water Resources
4.1 Introduction
4.2 Effects on Human Health and Environment
4.3 Physicochemical Methods for Metal Remediation
4.4 Bioremediation: A Solution to Pollution
4.5 Mechanisms of Bioremediation
4.6 Utilization of Nanoconjugates in Heavy Metal Remediation
4.7 Future Aspects
4.8 Conclusion
References
5 New Dimensions and Innovations in Microbes and Nanoconjugate-Based Bioremediation Technology
5.1 Introduction
5.2 Organic Pollutants Exposure to the Environment and Its Consequences
5.3 Microorganisms Mediated Remediation of Organic Pollutants
5.4 Advancement in Biodegradation Approach
5.5 Nanobioremediation Approach for Organic Pollutants
5.6 Microbes–Nanoconjugates Combined Approach for Remediation
5.7 Conclusion and Future Aspects
References
6 Application of Microbes and Nanoconjugates in the Removal of Inorganic Pollutants from Wastewater
6.1 Introduction
6.2 Inorganic Pollutants
6.3 Microbes as Remediators
6.4 Nanoconjugates
6.5 Synergistic Approach of Microbes and Nanoconjugates for Removing Inorganic Pollutants
6.6 Future Trends
6.7 Conclusion
References
7 Degradation of Dyes and Organic Pollutants
via
Microbes and Nanoconjugates from Textile Wastewater
7.1 Introduction
7.2 Textile Waste and Its Harmful Impact
7.3 Microbes for Bioremediation of Textile Wastewater
7.4 Role of Nanotechnology in Bioremediation of Textile Wastewater
7.5 Conclusion
7.6 Future Perspectives
References
8 Microbes and Nanoconjugated Assistants for Sensing and Detecting Pollutants in Wastewater
8.1 Introduction
8.2 Molecular Sensors
8.3 Nanosensors
8.4 Environmental Applications
8.5 Summary and Outlook
References
9 Nanobioremediation: A Sustainable Reclamation Method for Future Deployment
9.1 Introduction
9.2 Types of Nanomaterials Used in Nanobioremediation
9.3 Mechanisms of Nanobioremediation
9.4 Factors Affecting the Effectiveness of Nanobioremediation
9.5 Case Studies of Nanobioremediation
9.6 Challenges and Future Directions in Nanobioremediation
9.7 Conclusion
References
10 Nanoparticle-Assisted Microbial Removal of Arsenic (As) from Drinking Water Sources
10.1 Introduction
10.2 Microbe-Based Removal of Arsenic
10.3 Nanoparticles and Microbial-Synthesized Nanoparticles (MSNs)
10.4 Future Perspectives
10.5 Conclusion
Acknowledgement
References
11 Nanotechnology-Enabled Remediation of Oil Contamination in Polluted Water
11.1 Introduction
11.2 Nanotechnology for Bioremediation
11.3 Applications of Nanotechnology for Oil–Water Separation
11.4 Approaches for Conventional Oil–Water Separation
11.5 Drawbacks and Limitations of Nanotechnology-Based Techniques
11.6 Conclusion
References
12 Nano-Biocatalysis for Remediation of Pharmaceutical Micropollutants in Industrial Wastewaters
12.1 Introduction
12.2 Water Pollution and Sources of Micropollutants
12.3 Impact of Micropollutants on Environment and Human Health
12.4 Nano-Biotechnology and Its Role in Bioremediation
12.5 Bioremediation of Micropollutants Using Nano-Biocatalysis
12.6 Conclusion and Future Prospects
References
Index
End User License Agreement
List of Tables
Chapter 3
Table 3.1 A comprehensive overview of characterization techniques in nano-bior...
Table 3.2 A comprehensive overview of biosynthesized nanoparticles used for po...
Chapter 4
Table 4.1 Various mechanisms of metal bioremediation and their effectiveness.
Table 4.2 Nanomaterials and their heavy metal remediation potential.
Chapter 5
Table 5.1 Consequences of various POCs.
Table 5.2 Microbial degradation of organic compounds.
Table 5.3 Microbe–conjugates and their applications in remediation.
Chapter 6
Table 6.1 Adverse effects of various inorganic pollutants on health.
Table 6.2 Removal of heavy metals by microorganisms.
Table 6.3 Nanoconjugates for the remediation of heavy metals.
Chapter 7
Table 7.1 Bacteria, fungi, and microbial nanoconjugates in the bioremediation ...
Chapter 9
Table 9.1 Types of nanomaterials used in nanobioremediation.
Chapter 11
Table 11.1 A global review of the most significant oil spills that have occurr...
Table 11.2 Separation of oil and water using nanotechnology for the synthesis ...
Chapter 12
Table 12.1 Types of pharmaceutical micropollutants, biological functions, and ...
Table 12.2 Pollutants released by various industries responsible for water pol...
Table 12.3 Major health effects of micropollutants toxicity on animals.
Table 12.4 Nanomaterials for targeted remediation of micropollutants.
List of Illustrations
Chapter 1
Figure 1.1 Different possible mechanisms for microbe-nanoparticle conjugation.
Figure 1.2 Membrane separation process and their applications.
Figure 1.3 Major points to be considered while designing a wastewater treatmen...
Chapter 2
Figure 2.1 Basic classification of nanomaterials.
Figure 2.2 Mechanism of action of nanoparticle in bacterial cell [21].
Figure 2.3 Mechanisms of interaction between nanoparticles and the cell surfac...
Chapter 3
Figure 3.1 SEM images of (a) necrotic cell and (b) apoptotic cell. (c) sample ...
Figure 3.2 SEM images of (a) monomicrobial
S. aureus
, (b) monomicrobial
P. aer
...
Figure 3.3 SEM images of the zinc oxide nanoparticles (ZnO NPs) at different m...
Figure 3.4 TEM images: (a–b) Fungal-extract nanoparticle clusters, (c–d) Morph...
Figure 3.5 AFM images showing the dynamic process of (a) malathion and (b) par...
Figure 3.6 (a) Oxidized bare glassy carbon electrode (GCE), (b) and (d) DNA on...
Figure 3.7 FTIR spectra of SeNP nanoconjugate with Polyvinylpyrrolidone (PVP) ...
Figure 3.8 (A) Fitted X-ray photoelectron spectroscopy (XPS) data of Ce 3d orb...
Figure 3.9 (a) UV-visible absorption spectra showing the SPR band of PchNPs an...
Chapter 4
Figure 4.1 Hazardous effect of heavy metals on human health.
Figure 4.2 Simplified mechanisms of heavy metal bioremediation by bacteria.
Figure 4.3 Utilization of nanotechnology in heavy metal bioremediation.
Chapter 5
Figure 5.1 Techniques for synthesis of nanoconjugates.
Figure 5.2 Nanobioremediation technology.
Figure 5.3 Mechanisms involved in nanobioremediation.
Chapter 6
Figure 6.1 Microbial pathways to reduce heavy metal toxicity [16].
Figure 6.2 Microbial treatment strategies for inorganic pollutants [30].
Chapter 7
Figure 7.1 Mechanism of microbial nanoconjugates bioremediation [40].
Figure 7.2 Advantages of microbial nanoconjugates in bioremediation [41].
Chapter 8
Figure 8.1 Diagrammatic categorization of nanomaterials: CNTs, denoting carbon...
Figure 8.2 Nanobiosensor design: (a, c) synthesis and functionalization of mag...
Figure 8.3 Electrochemical sensing mechanism on a glassy carbon electrode modi...
Chapter 9
Figure 9.1 Biosorption.
Figure 9.2 Biocatalysis.
Figure 9.3 Biotransformation.
Figure 9.4 Biomineralization.
Chapter 10
Figure 10.1 Sources of arsenic pollution in water bodies.
Figure 10.2 Map showing groundwater arsenic contamination status of some regio...
Figure 10.3 Schematic representation illustrating the various approaches used ...
Figure 10.4 Mechanistic representation of the synthesis process of MSNs.
Chapter 11
Figure 11.1 A global scenario of oil spills since 1990.
Figure 11.2 Oil–water separation techniques for the synthesis of composites (a...
Chapter 12
Figure 12.1 Introduction of pharmaceutical micropollutants into the environmen...
Figure 12.2 Industries responsible for water inadequacy.
Figure 12.3 Nanotechnology-based environmental remediation strategies.
Guide
Cover Page
Table of Contents
Series Page
Title Page
Copyright Page
Preface
Begin Reading
Index
WILEY END USER LICENSE AGREEMENT
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Scrivener Publishing100 Cummings Center, Suite 541JBeverly, MA 01915-6106
Publishers at ScrivenerMartin Scrivener ([email protected])Phillip Carmical ([email protected])
Nano-Bioremediation for Wastewater Treatment
Edited by
Gajendra Singh Vishwakarma
Indian Institute of Forest Management, Bhopal, Madhya Pradesh, India
Narendra Kumar
Department of Biotechnology and Bioengineering, Institute of Advanced Research, Gandhinagar, Gujarat, India
Alok Pandya
Department of Biotechnology and Bioengineering, Institute of Advanced Research, Gandhinagar, Gujarat, India
and
Zinia Mohanta
Dept. of Radiology, Kennedy Krieger Institute, Johns Hopkins School of Medicine, Baltimore, USA
This edition first published 2025 by John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA and Scrivener Publishing LLC, 100 Cummings Center, Suite 541J, Beverly, MA 01915, USA© 2025 Scrivener Publishing LLCFor more information about Scrivener publications please visit www.scrivenerpublishing.com.
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Library of Congress Cataloging-in-Publication Data
ISBN 978-1-394-27161-0
Front cover image courtesy of Adobe FireflyCover design by Russell Richardson
Preface
The exponential growth of industrialization and urbanization over the past century has led to unprecedented environmental challenges, particularly in water pollution. Contaminants ranging from heavy metals and organic compounds to pathogenic microorganisms have rendered waste-water treatment a critical global priority. Traditional methods of waste-water treatment, while effective to an extent, often fall short in addressing the multifaceted and complex nature of modern pollutants. This scenario necessitates innovative and sustainable solutions, driving the scientific community to explore the potential of advanced technologies in environmental remediation.
One such promising frontier is nano-bioremediation. This emerging field synergistically combines nanotechnology principles with biological processes to develop cutting-edge solutions for wastewater treatment. Nanotechnology offers tools at an atomic and molecular scale that can enhance the efficiency, speed, and scope of bioremediation processes. The unique properties of nanomaterials, such as their high surface area-to-volume ratio, tuneable surface chemistry, and exceptional reactivity, make them ideal candidates for removing contaminants that are otherwise challenging to degrade or extract.
This book aims to provide a comprehensive overview of the state-of-the-art advancements and future directions in this dynamic field. It brings together contributions from leading experts and researchers, offering readers an in-depth understanding of the principles, methodologies, and applications of nano-bioremediation.
Structured to guide the reader through a logical progression of topics, this book starts with the fundamental concepts of nanotechnology and bioremediation, followed by detailed discussions on the synthesis and characterization of nanomaterials, their interaction with biological systems, and the mechanisms underlying their role in pollutant degradation and removal. Case studies and practical applications are presented to illustrate the real-world impact and potential of these technologies in various settings.
Special emphasis is placed on the sustainability and safety aspects of employing nanomaterials in environmental applications. The potential risks associated with nanotechnology, including toxicity and environmental impact, are critically evaluated alongside the benefits, ensuring a balanced perspective on the use of these advanced materials.
As we move towards a future where clean water resources become increasingly scarce, the integration of nanotechnology in bioremediation processes represents a promising pathway to sustainable water management. This book aspires to serve as a valuable resource for researchers, practitioners, policymakers, and students, providing them with the knowledge and tools needed to harness the power of nano-bioremediation for a cleaner and healthier environment.
We hope that this book will inspire further research and innovation in this exciting field and contribute to the development of practical solutions that can be implemented on a global scale. The journey towards effective and sustainable wastewater treatment is ongoing, and we are optimistic that the insights and discoveries shared in this book will play a significant role in advancing this vital area of environmental science. Finally, our gratitude goes to Martin Scrivener and the team at Scrivener Publishing for their support in bringing this volume to light.
Editors
Gajendra Singh Vishwakarma
Narendra Kumar
Alok Pandya
Zinia Mohanta
1Nano-Bioremediation and Scale-Up Techniques for Wastewater Treatment
Ananya Tiwari1, Isha Dharsandia1, Dharni Parekh1, Alok Pandya1, Narendra Kumar1, Shubhita Tripathi1 and Gajendra Singh Vishwakarma2*
1Department of Biotechnology and Bioengineering, Institute of Advanced Research, Gandhinagar, Gujarat, India
2Indian Institute of Forest Management, Bhopal, MP, India
Abstract
Providing enough affordable, clean water for everyone is the biggest challenge of the twenty-first century. In the past few decades, many techniques for treating wastewater have been investigated; however, their appliscation is limited by a number of issues, such as the use of chemicals, the production of disinfection by-products (DBPs), time commitment, and cost. Advances in nanotechnology have led to the development of products and processes used in wastewater treatment, such as magnetic nanoparticles, nanofiltration, nanobiocides, nanoadsorbents, and nanozero valent iron. Also, in the scenario of wastewater treatment, the production of bioengineered nanoparticles (BNPs) through microbial interaction plays a significant role. Being less costly and dangerous than traditional approaches, BNPs have been employed as biocatalysts, adsorbents, oxidants, and reductants in the removal of contaminants from drinking water and wastewater because they contain a special bacterial carrier matrix. Moreover in this regard, the use of microbial fuel cells (MFCs) has garnered importance due to the features of simultaneous power production and wastewater treatment. There is a need to scale-up all the available techniques in this aspect, at a large scale. For that, development is required in pilot or large-scale water treatment plants. In this regard, different studies are available in which various processes and parameters have been demonstrated that can be considered during the scale-up techniques and designing principles for optimum wastewater treatment. In this particular book chapter, we have discussed each and every aspect of the same in detail and also sheds light on the most recent developments in nanotechnology in light of the pressing need to investigate and manage the emerging hazardous wastes with reduced prices, less energy, and greater efficiency.
Keywords: Wastewater treatment, nano remediation, reverse osmosis, nanofiltration, ultrafiltration, microfiltration, fabrication, scale-up
1.1 Introduction
The ever-increasing demand for clean water necessitates the development of innovative and efficient water treatment technologies. Traditional methods, while effective, often struggle with emerging contaminants and require significant resources. This has led researchers to explore the exciting potential of microbes and nano-conjugates in wastewater treatment and water purification systems.
In the field of wastewater treatment and water purification, the integration of microbes and nanotechnology has shown great promise. Microbes, with their diverse metabolic capabilities, offer a biological approach to pollutant degradation. By harnessing their natural ability to break down organic matter and certain inorganic compounds, we can create targeted bioremediation solutions. Nano-conjugates, on the other hand, present a unique physicochemical approach. These engineered structures, on a scale of billionths of a meter, possess remarkable properties like high surface area and tunable reactivity. They can be designed for specific functionalities such as adsorption of contaminants, photocatalysis for pollutant degradation, or even sensing of specific pollutants. Various nanomaterials, including zeolites, chitosan, Multi-walled carbon nanotubes (MWCNT), nano-composites, and nano-oxides, have been employed in water treatment processes [1]. The microbial synthesis of nanoparticles has emerged as a cost-effective and environmentally friendly method, offering high absorbent capabilities due to their nanoscale size and unique properties. Additionally, the bioinspired production of nanomaterials through microorganisms has gained attention for its efficiency in treating wastewater and decontaminating pollutants, providing a sustainable and energy-efficient alternative [2]. Moreover, the use of nano microbial conjugates, such as phage-conjugated Fe3O4 nanoparticles, has demonstrated significant antibacterial activity against resistant strains in wastewater, highlighting a novel approach in water management systems [3]. Lastly, the application of titanium oxide nanoparticles in a lab-scale wastewater treatment plant has proven effective in enhancing water quality by reducing turbidity, total solids, suspended solids, and biological and chemical oxygen demands, as well as removing heavy metals and decreasing microbial counts [4].
Microorganisms play a vital role in augmenting water treatment efficacy. Their metabolic processes break down contaminants in wastewater, including organic matter, nitrogen, phosphorus, and other pollutants, into environmentally benign substances. Biological wastewater treatment processes [5] exploit diverse microbial communities to achieve this, leading to reductions in biological oxygen demand (BOD) and chemical oxygen demand (COD). This results in the generation of treated water suitable for reuse in various applications. Specific microbial species, such as Candidatus accumulibacter phosphatis, Spirogyra, Aspergillus luchuensis, and Candida, are instrumental in contaminant removal from wastewater sources [6]. Notably, the type of treatment technology employed influences the composition of microbial communities within wastewater treatment plants. Additionally, environmental factors such as dissolved oxygen concentration and pH significantly impact nitrogen metabolism and microbial interactions [7]. By leveraging microbial biotechnology, we can not only decrease the concentration of diverse water contaminants but also generate valuable energy products like biohydrogen, bioethanol, biogas, and bioelectricity [8].
Nano-conjugates offer distinct advantages in water purification. By combining the unique properties of various materials, they can enhance membrane performance. For instance, the functionalization of carbon nanotubes with diferuloylmethane creates a novel carbon conjugate for membrane reinforcement [1]. Additionally, nanomaterials like zeolites, chitosan, and various nano-composites and oxides showcase promise in pollutant removal [9]. Notably, nano-conjugates can simplify and increase purification efficiency, enabling large-scale production as demonstrated in the method for purifying water-soluble iron oxide nanoparticle-antibody conjugates [10]. Overall, nano-conjugates present a versatile and effective approach for improving water purification processes.
Newly designed prototypes play a crucial role in advancing water purification by incorporating innovative and cost-effective methods. For instance, a prototype for aid workers integrates activated carbon, ceramic candle filtration, and UV irradiation to effectively remove bacteria, turbidity, and viruses from water sources in underdeveloped regions. Similarly, a recently developed system in Pakistan utilizes gravity flow to address arsenic contamination in groundwater, significantly reducing heavy metal levels post-treatment [11]. Furthermore, a domestic wastewater treatment prototype employs a two-filter system for efficient wastewater treatment, producing clean water for reuse [12–15]. These prototypes showcase advancements in water purification technology, addressing various contaminants and improving water quality for diverse applications.
Keeping the above discussion in mind, this chapter will discuss the basics of nanobioremediation along with the fabrication and scale-up techniques for microbes and nano-conjugate based prototypes of waste-water treatment via emphasizing the different matrix for the microbes and nano-conjugate fabrication factors of scale-up of water treatment plant (size, capacity, aeration, filtration).
1.2 Basics of Nanobioremediation
Nanobioremediation is one such method that has gained popularity in recent years.
Bioremediation entails the use of plants, enzymes, and microbes, or a combination of these, for biosorption, bioaccumulation, biotransformation, and biological stabilization. It functions as a remediation approach for removing inorganic, organic, and emergent pollutants from agricultural soil [3]. In the case of nanobioremediation, by combining the concepts of bioremediation with nanotechnology, nanobioremediation may remove pollutants from soil, water, and air more precisely and efficiently. The fundamental idea is to use manufactured nanomaterials, such as nanoparticles, to enhance the natural processes that microbes do to break down pollutants and detoxify the environment. Combining the natural processes of bioremediation with the power of nanotechnology is a revolutionary technique known as nanobioremediation [2].
1.3 Basics of Wastewater Treatment Plant
Water is an invaluable resource, and understanding its treatment is essential before the construction of any wastewater treatment facility. Wastewater, in its simplest terms, is water that has been contaminated through residential, commercial, and industrial activities [21]. The heterogeneous and dynamic chemical composition of wastewater presents challenges in its precise definition. Wastewater treatment encompasses a series of processes designed to meet specific standards or discharge quality, as mandated by regional or federal regulatory authorities. These processes are crucial in mitigating the environmental impact of wastewater and ensuring the sustainability of water resources. Wastewater is typically classified into two categories based on its source: domestic wastewater and industrial wastewater [22].
Domestic wastewater, also known as municipal wastewater or simply sewage, is produced by a community of people. This type of wastewater is discharged from residences and collected from nearby commercial, institutional, and public institutions. Sewage is a combination of water, human waste, leftover bathroom water, food preparation residue, laundry detergent, and other waste materials from daily life. In general, it contains organic and inorganic solids and microorganisms, mainly bacteria. The composition depends on its source and the generation of waste [23]. In industrial treatment plants, water is used for manufacturing processes including fabrication, processing, washing, diluting, cooling, or transporting products, as well as for facility cleanliness, in large and medium-scale industries. Water quality and quantity vary depending on the industry and its process methods. Pollutants including heavy metals (Cd, Ni, Pb, Hg, As, Cu, and Cr), a high amount of organic matter, dyes and chemicals, suspended particles, and pathogenic microbes are what define industrial wastewaters [24].
1.3.1 Treatment Methods
A centralized facility can treat wastewater using a variety of methods. These methods are developed to meet effluent regulations, and technologies and processes are often chosen depending on their ability to effectively treat specific wastewater produced by a community or company [25]. Three types of treatments are usually applied for wastewater treatments which are physical, chemical, and biological treatment. Screening, primary treatment, secondary or biological treatment, polishing (disinfection and filtration), and sludge treatment are among the treatment procedures used in many conventional wastewater treatment facilities [25]. For the physicalmethods, aeration, sedimentation, or thermal effect are used in mechanical preparation. In this method, screens, filters, and sieves are used for the separation of liquid and major solid substances. The purpose of separating certain particles from wastewater is to prevent blockages in pumps and pipes, as well as reduce equipment wear [26]. After the physical treatment, biological procedures are applied for sludge digestion, biochemical oxidation, and anaerobic digestion. After the biological treatment, the chemical treatment is used for precipitation, flocculation, disinfection, and neutralization of the process [27]. For the membrane-based procedures, osmosis, nanofiltration, and filtration are used [28].
1.3.1.1 Primary Treatment
Primary treatment is based on the concepts of sedimentation, gravity, and filtering. In a traditional wastewater treatment facility, the suspended particles are eliminated via sedimentation and gravity [29]. The basic principle of this treatment is to remove large floating objects such as rags and sticks that might clog pipes or damage equipment. Primary clarifiers, sedimentation basins, settling basins, or primary settling tanks are examples of traditional methods or equipment used to carry out conventional primary treatment. Examples of more recent technologies include the lamella separator or clarifier, which also uses sedimentation; rotating belt filters (RBF), which similarly use filtration; and nano or micro-bubbles, which help simpler flotation of suspended solids in situations such as dissolved air flotation or induced gas flotation [30].
1.3.1.2 Secondary Treatment
Secondary treatment involves biological processes. Carbon, nitrogen, and phosphorus that are present in wastewater in either a dissolved or particulate form are removed by secondary or biological treatment [31]. Secondary treatments are designed to reduce the amount of organic materials in the wastewater. Typically, secondary sedimentation or a clarifying stage comes after the aeration process that grows the microorganisms in the wastewater in a conventional biological treatment. This process was also referred to as the activated sludge technique when it was initially created more than a century ago [32]. Activated sludge operations currently include most biological wastewater treatment methods that use air or oxygen to create a more easily separated mass of bacteria and other wastewater particles [33].
1.3.1.3 Disinfection-Filtration Treatment
The effluent of secondary treatment is usually free from dense solids or sludge as it goes onto the disinfection and filtration steps, sometimes referred to as polishing or tertiary treatment [34]. The goals of disinfection and filtration are to guarantee that the wastewater is free of hazardous levels of substances that cause illness or hazardous microorganisms before it is discharged back into the environment or utilized again by a municipality for purposes like cooling, toilet flushing, farming, etc. [35]. The treated effluent has to be sampled to see if it satisfies the discharge requirements specified by regional or national regulations before it may be released into the environment or used again as clean water [36]. Samples are taken from the different treatment tanks for analyzing the water quality. The most common measures of water quality are phosphorus, nitrogen, fecal coliform or bacteria, chemical oxygen demand (COD), biochemical oxygen demand (BOD), and nitrogen [37].
1.3.1.4 Sludge Treatment
Although sludge is abundant in minerals and nutrients, it includes hazardous microbes and other particles that can disturb natural habitats, just like wastewater does before it is filtered and disinfected [38]. Before being kept or utilized again, it is generally treated to lessen such pathogens and chemicals. A modern sludge treatment procedure is used on the sludge from primary and secondary treatment to recover nutrients and biogas, lessen pathogens, and decrease quantities of biosolids [39]. Sludge is frequently just dewatered and sometimes even limed before being disposed of or applied to land. Sludge may be used by certain wastewater treatment facilities to create premium soil products and fertilizers.
1.4 Secondary Treatment Systems
The wastewater treatment process removes and separates contaminants from wastewater [40]. There are two different types of wastewater treatment: domestic wastewater treatment and industrial wastewater treatment [22]. The treatment facility for household wastewater is referred to as a sewage treatment plant. Domestic wastewater is sometimes known as sewage or municipal wastewater [41]. The primary and secondary stages of waste treatment are the two fundamental phases. In the primary stage, solids are extracted from wastewater and allowed to settle. Further, waste-water is purified by biological processes in the secondary stage [42]. In some cases, these phases are integrated into a single procedure. Before the wastewater is released into a disposal field for ultimate treatment and soil dispersal, secondary wastewater treatment uses a biological treatment method to lessen the amount of organic components in the wastewater [43]. Compared to a septic tank, secondary treatment generates substantially higher-quality wastewater [44].
The secondary treatment based on activated sludge has the following functions: The naturally occurring bacteria in the wastewater are exposed to ambient air or are pumped with air or oxygen [45]. Usually, an aeration tank or basin is used for this. Certain organic compounds in waste-water, such as lipids, sugars, and other biodegradable substances found in food and human waste, are consumed and reproduced more easily by these microbes when there is oxygen present [46]. The microbes and other organic substances multiply, becoming denser and forming a biological floc. In the secondary sedimentation or clarity process, it separates as secondary or waste activated sludge (WAS) because it can then settle out or float more readily [47]. The effluent continues on to polishing or disinfection, while WAS, or secondary sludge, undergoes sludge treatment. Aeration tanks, basins, membrane bio-reactors (MBR), trickling filter bed filters, moving bed biofilm reactors (MBBR), integrated fixed film reactors, biological aerated filters (BAF), and sequencing batch reactors (SBR) are among the technologies used for biological treatment [48]. Rotating belt filters, dissolved air flotation tanks, and secondary clarifiers can all be used for the secondary sedimentation or clarity process, and the sequencing batch reactors cover all steps in the same unit [49].
1.4.1 Types of Secondary Treatment
Microorganisms are added to wastewater as a secondary wastewater treatment step, and these microorganisms use metabolic processes to extract waste from the water. Anaerobic, anoxic, and aerobic treatment are the three categories of secondary treatment. Although the biological mechanism behind each technique varies, they all successfully purge water of contaminants.
1.4.1.1 Aerobic and Activated Sludge Treatment
Aerobic treatment systems convert organic contaminants into water, carbon dioxide, and more as by-products. Microorganisms that need oxygen for their metabolic functions are used in this treatment approach. In aerobic treatment systems, oxygen is added to wastewater through aeration, which in turn feeds microorganisms that eat the wastewater’s waste [31]. Activated sludge treatment is a common aerobic process. This process uses a sludge layer made of clumped biosolids called flocs, together with flocculation and aeration [50]. These flocs develop during the aeration process and settle to the bottom of the water tank. During the activated sludge treatment process, water treatment plants use secondary clarifiers to mix settled sewage with raw or primary sludge [51]. Then, to give the microorganisms in the return sludge more time to break down waste, they rely on air compressors to add compressed air to the mixture and push the flocs back into the water within the aeration tank. Treatment centers provide a variety of techniques and resources for this type of treatment.
1.4.1.1.1 Surface Aerators or Diffusers
To introduce air into the water, some treatment facilities utilize surface aerators in lagoons. Other plants employ ceramic diffusers or rubber membranes in their aeration tanks [52]. An aeration tank pumps air through a tube or disc-shaped diffusers that have several microscopic holes in them. Through the holes, little air bubbles are let into the aeration tank [53]. These bubbles rise through the water tank to aid in oxygen transfer and aerobic digestion.
1.4.1.1.2 Media Filters
Certain treatment facilities use media filters to encourage aerobic digestion. A typical media filter system is the moving bed biofilm reactor (MBBR) technology [54]. Thousands of tiny plastic media fragments are used in a basin by this kind of device. Bacteria attach to the media pieces and create a biofilm on them. The media particles cover between 50% and 70% of the basin’s capacity and provide surface areas for bacterial growth. Because of their density, the pieces make the most of the available area by floating throughout the water [55]. With several tiny spokes like a wheel, each complex media component maximizes the surface area available for bacterial growth. The optimal shape and density of media pieces allow them to reach as much waste as possible and efficiently digest it to reduce hydraulic retention time [56].
1.4.1.2 Anaerobic Treatment
Anaerobic techniques produce biofuel gas from organic pollutants without the need for oxygen [57]. This procedure, which frequently takes place in enclosed digestive lagoons, operates without the need for oxygen. Anaerobic microorganisms in the lagoons decompose organic waste [58]. Since anaerobic digestion does not require a pump to introduce oxygen into wastewater, it consumes less energy than aerobic digestion. Methane, carbon dioxide, and water vapor are common biogas by-products of anaerobic water treatment [59]. The resulting methane is frequently used by wastewater treatment facilities as plant fuel. Anaerobic treatment is the ideal choice for facilities that handle wastewater containing large amounts of biodegradable materials, such as food waste, animal dung, or municipal trash [60].
1.4.1.3 Anoxic Treatment
Anoxic treatment uses microbes with no oxygen metabolic pathway to purify the water. This activity can take place in the presence of some oxygen in the form of sulfates, nitrates, or nitrites, but it does not require free molecular oxygen to proceed [61]. This procedure is frequently used by plants to denitrify wastewater with a high nitrogen concentration. Nitrogen is converted to nitrate by anoxic denitrification using a trickling filter or a suspended growth system [62]. After that, certain bacteria are added by the wastewater treatment plant to break down the nitrogen in the nitrate, leaving behind just oxygen molecules. Treatment facilities usually completely surround their reactors to mitigate the effect of radicals of oxygen [63].
1.5 Different Matrix for the Microbes and Nano-Conjugate Fabrication
In the dynamic realm of science and technology, the fusion of seemingly unrelated elements often leads to groundbreaking innovations. A notable example of this is the collaboration between microbes, the smallest forms of life on Earth, and nanoparticles, the marvels of the material world. This interaction, termed “microbe and nanoparticle conjugation,” has emerged as a significant area of research and discovery, offering a wide range of applications across biotechnology, medicine, environmental science, and beyond. The combination of these two distinct entities in modern science frequently results in unique properties and potential applications, driving forward transformative advancements [64].
Nanoparticles (NPs) are ultra-small particles with unique properties due to their size, typically ranging from 1 to 100 nanometers. They exhibit high surface area, enhanced reactivity, and distinct optical, electrical, and magnetic characteristics [65]. These properties make them valuable in various fields, from medicine to materials science and electronics. Immobilized microbial cells have superior operational stability, are easier to separate from products for potential reuse, and have sufficient catalytic efficiency as compared to lose cells, they are widely utilized in bioconversion, bio-transformation, and biosynthetic processes. Because of their high surface energy and large specific surface area, the NPs’ nano-size effect causes them to be heavily adsorbed on the surfaces of microbial cells. The interaction force between cells and NPs also heavily relies on electrostatic interactions. The primary mechanism of NP-coated bacterial cells was thought to be an electrostatic interaction between the positive and negative charges of magnetite NPs and the surface of the bacteria [66]. NPs have the ability to create hydrogen bonds with the extracellular matrix. Extracellular polymeric substances (EPSs), which are also rich in functional groups including carboxyl, hydroxyl, and phosphate groups, frequently coat the surfaces of cells [67].
Conjugation of microbes and nanoparticles is a technique that involves attaching or linking nanoparticles to the surface of microorganisms, such as bacteria or yeast cells. The result is a hybrid entity that amalgamates the biological functionalities of microbes with the exceptional properties of nanoparticles. These hybrid entities, or conjugates, hold immense promise across an array of applications, opening up new horizons for science and technology Figure 1.1 [68].
Figure 1.1 Different possible mechanisms for microbe-nanoparticle conjugation.
The significance of this conjugation lies in the extraordinary combination of features it provides. Microbes are inherently gifted with a wide spectrum of biochemical processes, encompassing the ability to metabolize various compounds, produce enzymes, and even carry out specialized functions, such as bioremediation or drug synthesis. Nanoparticles, on the other hand, exhibit unique physical and chemical properties that can be finely tuned and harnessed for specific applications. The choice of nanoparticles is a pivotal decision in microbe and nanoparticle conjugation, as it profoundly influences the resulting hybrid material’s properties and applications [69].
1.5.1 Conjugation Criteria for Nanoparticles
The most important criterion for conjugation in regards to nanoparticles is the selection of stable and economical nanoparticle that has biocompatibility and is non-toxic. In [70–74] nanoparticles were utilized like iron oxide, α-Fe2O3, Fe3O4, and γ-Al2O3 for performance efficiency testing, respectively.
Sometimes, it is necessary to conduct surface oxidization of the nanoparticles to achieve improved efficiency in bioremediation. This is because work by Lu et al. [75] has shown that naked NPs oxidize easily and lose their magnetism and dispersibility. Polydopamine, oleic acid, ammonium oleate, and glycine are utilized for surface modification. This is because covalent bonds are formed between cells and carriers, which is a strong binding mode and enhances their stability for use in wastewater treatment.
Different nanoparticles also need varied times and temperatures for stable conjugation with host microbes. Feng et al. [76] tabulated essential combinations of temperature, time, and microbe-NP ratios essential for stable conjugations.
Poorly soluble NPs (e.g., gold, palladium, silver sulfide, and platinum) are less toxic to the host microbial cells compared to other metal or metal oxide NPs.
1.5.2 Conjugation Criteria for Microbes
The successful conjugation of microbes with nanoparticles requires specific criteria to be met. Microbes should have the capability to degrade or immobilize the target contaminants present in the wastewater or environmental system. The selection of microbial strain is one of the most essential criteria for remediation efficiency. El Bestawy et al. [77] created conjugates using microbial consortia while genetically engineered bacteria were employed by Zhang et al. [70]. Microbes should be able to adhere to the nanoparticles and remain stable during conjugation, ensuring their continued function. Conjugation should lead to improved microbial activity, such as increased pollutant degradation rates or metal ion biosorption capacities. The nanoparticles used should not be toxic to the microbes; they should not affect microbial growth, viability, or metabolic functions or cause detrimental effects on the environment. Surface functionalization involves modification of the nanoparticles’ surfaces with ligands or coatings to enhance microbial attachment, stability, and interactions allowing them to withstand environmental conditions and shear forces. Meeting these criteria is essential for ensuring the successful and safe application of microbe-nanoparticle conjugates in various fields, including wastewater treatment and environmental remediation.
1.6 Factors of Scale-Up of Water Treatment Plant
According to the pore size, water treatment techniques use a variety of membrane types, including reverse osmosis (RO), nanofiltration (NF), ultrafiltration (UF), microfiltration (MF), and particle filtration [78].
1.6.1 Reverse Osmosis (RO)
RO membrane technology finds extensive application in brackish water treatment, wastewater treatment, drinking water production, and seawater desalination. At an energy cost of about 1.8 kWh/m3, which is significantly less than other technologies, RO is currently the most energy-efficient desalination technique [79]. The solvent travels from the region of low to high solute concentration in the naturally occurring osmosis process to equalize the solute concentration on both sides of the membrane, producing the osmotic pressure. The direction of solvent flow is changed by applying pressure on the RO membrane (Figure 1.2) [80].
Figure 1.2 Membrane separation process and their applications.
In RO desalination operations, scaling and membrane fouling are two critical concerns because foulants and inorganic scalants typically coexist in the feed water and have attracted significant attention [80]. In actual RO plants, remediation techniques like membrane cleaning are only used if a high level of irreversible fouling, indicated by a drop in permeate flux of about 15–20%, has occurred in the membrane module. Usually, the application of costly and membrane-damaging chemicals is required to remove hard scales and restore the modules’ performance to almost their initial levels. Designing and developing methods for ongoing membrane element monitoring and quantifying the scale deposition that is occurring is therefore critically needed [81].
1.6.1.1 Overview of Nanofiltration Membranes
Nanofiltration (NF) is an extremely complicated process and is dependent on the interfacial and microhydrodynamic events that must take place at the membrane surface and in the membrane nanopores. A combination of the Donnan, dielectric, steric, and transport mechanisms may be responsible for rejection from NF membranes. Several experiments on ultrafiltration (UF) membranes have proven that neutral solutes are transported through the steric mechanisms, which are based on size-based exclusion [82]. Water and wastewater treatment applications for nanofiltration membranes are wide-ranging. They have many advantages, including high flux, high retention of organic molecules and multivalent metal ions, low operating pressure, comparatively minimal investment, and low operation and maintenance costs [83].
1.6.2 Techniques for Fabricating Nanofiltration Membranes
The fabrication of NF membranes can be done in a variety of ways, such as by layer-by-layer assembly, electron beam irradiation, interfacial polymerization, UV/photo-grafting, plasma treatment, and the insertion of inorganic and organic particles [84]. Membrane surface design should take into consideration the physicochemical characteristics of both the membrane and the solute to minimize fouling, as separation and fouling are dependent upon the membrane surface. Through surface engineering, it is possible to increase surface hydrophilicity, decrease surface roughness, introduce antibacterial layers, increase surface charge, and increase the solute’s steric repulsion at the surface. One feasible approach to reduce membrane fouling is to improve antifouling qualities by surface modification. There are two broad strategies that have been extensively studied: grafting polymer chains onto the membrane surface and applying a thin film covering [85]. The simplest of these alterations is a combination of inorganic and organic components. By integrating nanoparticles into NF membranes, contaminants from wastewater can be removed more effectively because of the particles’ high aspect ratio, reactivity, and variable pore volume, electrostatic, hydrophilic, and hydrophobic reactions [86]. NF and RO processes have denser membranes (e.g., RO) and smaller pores (e.g., NF), these techniques are able to produce treated wastewater of higher quality than MF/UF [85, 87].
1.6.3 Microfiltration Membrane
Microfiltration (MF) membrane process is a low-pressure membrane process. They function similarly to traditional coarse filtration in that they are employed to retain suspended material particles. The normal operating pressure range for membranes is between 0.5 bar and about 3 bar, with pore size ranging from 0.05 to 10 microns. This is useful for separating emulsions and suspensions. Colloidal matter and suspended particles are moderately removed by MF membranes. It is possible to retain about 40% of the organic material. In 10 years, a number of MF membrane materials were discovered. MF membranes can also be produced in multiple layers, with or without filters, like NF and RO membranes. The membrane structure is made up of active and support layers [88]. The widely recognized MF operations are defined and divided into two categories: ceramic and polymeric membranes.
1.6.3.1 Ceramic Membranes
The development of low-cost, high-potential ceramic membranes during the last 20 years has generated interest from manufacturers and environmentalists for a range of environmental applications [40]. Ceramic membranes that are used to treat water and wastewater often have asymmetric structures made up of a permeable supporting layer, an intermediate layer, a thin selective layer, and a thin skin top layer with different densities depending upon the desired molecular weight cut-off (MWCO) of the ceramic membranes. Both types of materials, known as integrated or composite ceramic membranes in this instance, can be utilized to make all of the layers. Both types of materials have been used to filter industrial effluents [89]. It is significant to note that intermediate and support layers provide the required selectivity in addition to stability and strength, and the thin selective layer achieves the separation purpose [39]. Several techniques can be used to produce ceramic membrane supports depending on the materials to be used, the desired membrane structure, and the application requirements. The most widely used manufacturing techniques include extrusion, slip casting, pressing, and freeze casting [90].
1.6.3.2 Polymeric Membrane
Polymeric membranes are the first choice of industry due to their high application suitability and low cost. The most crucial requirement for polymeric membranes is affinity toward a certain component. It is also simple to regulate the membrane’s pore size during production in polymeric membranes. For the installation, there must be a high degree of flexibility and minimal space. Every time, we must select a polymer based on the requirements of the assignment. Common examples of polymeric membranes are cellulose acetate (CA), polyacrylonitrile (PAN), polyimide, polycarbonate (PC), polyethylene (PE), polypropylene (PP), and polytetrafluoroethylene (PTFE). Typically, metal/metal oxide or carbon nanotubes (CNTs) are incorporated into polymers such as polyvinylidene fluoride (PVDF) ultra-filtration membranes to enhance their performance [91–93].
1.7 Existing Studies on Scale-Up Techniques and Design Principles
Scaling up wastewater treatment technology involves transitioning from small-scale experiments to large-scale functional treatment plants, employing several key techniques and considerations. Microfluidic reactors offer precise control over mixing and reaction conditions, enabling the production of larger volumes of conjugated microbes by operating multiple units in parallel. Membrane-based separation techniques like tangential flow filtration facilitate the continuous processing and efficient concentration of the conjugated microbes. Additionally, immobilizing the conjugated microbes on carrier materials such as beads or fibers can create easily separable biocatalysts, allowing for reuse and simplifying the overall treatment process. The characteristics of the wastewater, such as the type and concentration of contaminants, can influence the choice of nanoparticles, microbes, and conjugation methods. Regulatory considerations must be factored in to ensure compliance with guidelines governing the use of nanoparticles in wastewater treatment.
Maintaining the stability of nanoparticle-microbe conjugates during scale-up is critical, as factors like shear stress and altered mixing conditions can affect attachment stability. Ensuring microbial viability is another major concern, necessitating proper nutrient supply, oxygen levels, and temperature control in larger systems. Cost and efficiency are crucial, requiring the development of cost-effective methods for nanoparticle synthesis, microbe culturing, and conjugation, alongside optimization of reaction times and minimization of reagent waste. The potential environmental impact of nanoparticles also demands careful consideration, including life cycle analysis, toxicity assessment, and end-of-life management.
Recent advancements in scaling up wastewater treatment techniques involve integrating emerging technologies such as nanomaterials, molecular tools, and artificial intelligence (AI) [94, 95]. Nanoparticles like zeolites, chitosan, and various nanocomposites have proven effective in removing pollutants from water streams, while molecular tools based on rRNA gene sequences have improved the understanding of water microbiomes without relying on culture-based methods [96]. Additionally, AI technologies have transformed water treatment processes by automating facilities, reducing costs, and minimizing human errors [97]. These innovations not only enhance the efficiency of wastewater treatment but also contribute to the development of sustainable and effective large-scale water purification systems, addressing the challenges of increasing water scarcity and pollution [98].
Real-world examples illustrate successful methods for scaling up waste-water treatment technologies. For example, an Italian study reviewed existing research (n=76) and identified the need for larger-scale experiments to validate the potential of Constructed Wetlands (CWs) for pollutant removal [99]. In Egypt, a novel approach using microalgae in wastewater treatment demonstrated promising results in a full-scale system, achieving a 97.3% return on investment. This case highlights the sustainability and efficacy of microalgae for pollutant removal [44]. Additionally, a project in China implemented a combination of coagulation pre-treatment and biochemical treatment, achieving a high average removal rate of chemical oxygen demand (COD) of 73.49%. This exemplifies successful scale-up strategies in the context of industrial wastewater treatment [1].
A study investigated the complexities of scaling up electrochemical and photoelectrochemical oxidation processes with diamond anodes for organic pollutant removal and disinfection of municipal wastewater. This work highlighted the significance of mass transfer conditions and the influence of UV irradiation [1, 16–18]. Another study introduced a novel wastewater treatment system employing a constructed up-flow wetland with Alfa grass as a substrate. This system demonstrated substantial removal rates for a variety of pollutants and heavy metals [94]. Furthermore, a separate study evaluated the operational parameters and contaminant removal efficiency of a microbial fuel cell stack system operating without external electricity input. This research showcased high removal efficiencies for chemical oxygen demand, biological oxygen demand, total nitrogen, and total phosphorus in the treated effluent, suggesting its potential as a sustainable and energy-efficient technology for domestic wastewater treatment [100]. Collectively, these studies emphasize the importance of adopting and scaling up innovative wastewater treatment technologies to effectively address environmental pollution.
Scaling up a laboratory-level wastewater treatment technique involves moving from small-scale experiments to larger systems, introducing complexities related to mass transfer, mixing, and safety. This process necessitates careful consideration during the design and prototyping of a laboratory-scale plant. It begins with a thorough evaluation of the process, understanding the laboratory-scale operations, identifying critical parameters, kinetics, and microbial behaviors, and assessing the feasibility of scaling up [19, 20]. Efficient mass transfer and mixing are vital, necessitating careful attention to tank geometry, baffling, and mixing equipment to ensure proper treatment throughout the larger volume. Hydraulics, including wastewater flow patterns, pipe sizes, and pumping capacities, must be managed to ensure even distribution. Effective solid-liquid separation is critical, with techniques like sedimentation tank design and sludge thickening needing adaptation for larger volumes. Key factors to consider include substrate availability, reactor design, and safety. Important design considerations include the type of reactor (e.g., up flow-anaerobic sludge blanket (UASB) reactor, activated sludge, or membrane bioreactors), sizing [calculating the necessary reactor volume based on influent flow rate, hydraulic retention time (HRT), and organic loading rate (OLR)], hydraulic design (ensuring efficient flow distribution and minimizing dead zones), mixing and aeration (planning effective mixing and aeration to maintain microbial activity), and selecting appropriate materials (using durable materials like stainless steel, glass, plastic, or concrete suitable for the scale and wastewater characteristics). Material selection for construction should consider the potentially corrosive nature of wastewater, ensuring durability. Automation and control systems are essential for large-scale operations, facilitating process control, monitoring, and data acquisition for efficient plant management.
Operational parameters such as adjusting the HRT and OLR based on larger flow rates and pollutant loads, managing temperature and pH variations, maintaining sludge retention time (SRT) for stable microbial communities [101, 102], and assessing nutrient requirements (e.g., nitrogen, phosphorus) for optimal performance should also be considered [103–105]. The larger reactor should be seeded with well-adapted sludge from the lab-scale system as inoculum, and parameters like biogas production [106], pH, and volatile fatty acids should be continuously monitored during start-up and operation. Additionally, safety and compliance must be addressed by managing potential risks (e.g., biogas accumulation and chemical exposure) [107] and ensuring adherence to environmental regulations and permits. Issues should be promptly addressed, and the process should be adapted based on performance data as needed.
Figure 1.3 Major points to be considered while designing a wastewater treatment plant system.
Scaling up wastewater treatment presents several significant challenges. Population growth and industrial development contribute to a continual rise in wastewater generation, necessitating the implementation of robust treatment strategies [108]. Discharging untreated wastewater into natural water bodies exacerbates freshwater scarcity, highlighting the critical need for efficient treatment methods [109]. The presence of toxic substances and emerging contaminants in wastewater further complicates the issue, demanding advanced treatment processes to safeguard both environmental and human health [110]. Furthermore, managing wastewater treatment facilities presents difficulties in contaminant identification and analysis, coupled with the energy-intensive nature of existing treatment processes. These factors emphasize the need for sustainable and energy-efficient solutions in wastewater treatment scale-up initiatives [111]. Fortunately, advancements in green and innovative treatment technologies offer promising solutions to minimize energy consumption and enhance environmental sustainability in wastewater management (Figure 1.3) [112].
Standardizing scale-up techniques for wastewater treatment on a global scale presents a complex but critical challenge. Advancements in microbial electrosynthesis (MES) hold promise for tackling issues like excess renewable energy storage and increasing yields of organic substances [108]. Nanotechnology, particularly materials like zeolites and nanooxides, demonstrates potential for efficient pollutant removal in water treatment. However, the absence of established standards necessitates further research in this area [1]. Global efforts emphasize the development of water treatment techniques that minimize energy consumption while maximizing performance to meet stringent effluent discharge standards [113]. The evolution of analytical techniques, including biosensors and nanosensing platforms, facilitates real-time monitoring and supports the development of advanced treatment methods like microbial fuel cells and membrane filtration [94]. While wastewater treatment presents multifaceted challenges, a holistic approach that addresses both societal and environmental concerns is essential for effective solutions.
1.8 Cost Reduction, Energy Efficiency, and Improved Performance
According to Zhao and Zhang [114], the presence of contaminating bacteria allowed photosynthetic bacteria (PSB) to continue dominating the system, increase biomass, and clean the wastewater from soybeans in an efficient manner. Microbiological cultivation costs can be considerably reduced by creating economical media from agricultural waste or industrial byproducts. Moreover, this may increase process durability. The cultivation of methanotrophs as a monoculture and in conjunction with green microalgae to upgrade remaining nutrients to SCP (single cell protein). By increasing the biomass yield per unit volume through the use of high-density culture techniques, the overall expenses associated with bio-reactor operation and maintenance can be decreased [115]. By integrating cultivation-dependent and cultivation-independent approaches, this study emphasized greater insights into the diversity of nitrogen-incorporating populations in the wastewater treatment process, thereby increasing existing understanding of nitrogen-incorporating bacteria. Additionally, the data show that wastewater from power plants has a high probability of producing biomass, biodiesel, and irrigation water. Transitioning from batch to continuous cultivation techniques might result in cost savings by increasing output and decreasing idle time [116].
Inorganic, organic, pharmaceutical, and heavy metal contaminants can be efficiently and economically removed from aqueous streams using green synthesized and biogenic nanocatalysts and nanomaterials. Their larger applications in wastewater treatment depend on their low production costs [117]. Reducing the cost of production can be achieved by synthesizing nano-conjugates from cheap and plentiful basic materials. For example, utilizing plant extracts as reducing agents instead of traditional chemical procedures can result in a more affordable way to synthesize metallic nanoparticles. Reducing waste disposal and regulatory compliance expenses can be achieved by using environmentally friendly techniques like biosynthesis or non-toxic solvents. Creating scalable synthesis techniques, such as flow chemistry or microwave-assisted synthesis, can reduce expenses and increase manufacturing efficiency [118, 119].
A viable method is the in-situ production of nanoparticles in microbial cultures. Pseudomonas aeruginosa was used to synthesize gold nanoparticles in situ, which greatly improved the microbial breakdown of phenolic compounds in wastewater [120]. Minimal modifications are required to retrofit the co-cultivation system into wastewater treatment plants that are already in place. This adaptability enables a gradual and economical switch to more effective treatment procedures. The efficiency of bioreactors has increased significantly with the incorporation of advanced sensors to monitor crucial parameters. The utilization of optical sensors in a bioreactor for microbial fermentation allows for real-time monitoring of biomass concentration and metabolite synthesis [121].
Recent developments in biopolymers and nanomaterials provide more affordable, high-performing options. The application of bio-based nanocomposites for the filtration of water has demonstrated promising results in terms of cost and effectiveness [122].
1.9 Conclusions
In conclusion, the escalating demand for clean water underscores the necessity for innovative and efficient water treatment technologies. Traditional methods, while reliable, face challenges with emerging contaminants and high resource demands. The integration of microbes and nanotechnology in wastewater treatment and water purification presents a promising solution. Microbes, with their diverse metabolic capabilities, provide a biological approach to pollutant degradation, while nanoconjugates offer a physicochemical strategy with their high surface area and tunable reactivity. The synthesis of nanoparticles by microorganisms and the development of nanomicrobial conjugates have shown significant potential in treating wastewater and enhancing water quality. Moreover, newly designed and revamped prototypes incorporating advanced materials and fabrication techniques further contribute to the efficiency and scalability of water purification systems. As these technologies continue to evolve, they hold the potential to address global water scarcity and contamination issues more effectively, paving the way for sustainable water management practices.
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