Abatement of Environmental Pollutants: Trends and Strategies

By Pardeep Singh and Ajay Kumar

Abatement of Environmental Pollutants: Trends and Strategies addresses new technologies and provides strategies for environmental scientists, microbiologists and biotechnologists to help solve problems associated with the treatment of industrial wastewater. The book helps readers solve pollution challenges using microorganisms in bioremediation technologies, including discussions on global technologies that have been adopted for the treatment of industrial wastewater and sections on the lack of proper management. Moreover, limited space, more stringent waste disposal regulations and public consciousness have made the present techniques expensive and impractical.

Therefore, there is an urgent need to develop sustainable management technologies for industries and municipalities. To remove the damaging effect of organic pollutants on the environment, various new technologies for their degradation have been recently discovered.

• Covers bioremediation of petrochemical pollutants, such as Benzene, Toluene, Xylene, Ethyl Benzene, and phenolic compound
• Includes discussions on genetic engineering microbes and their potential in pollution abatement
• Contains information on plant growth promoting bacteria and their role in environment management

• Language: English
• Publisher: Elsevier Science
• Release date: Aug 27, 2019
• ISBN: 9780128180969

Book preview

Abatement of Environmental Pollutants

Trends and Strategies

Editors

Pardeep Singh

Ajay Kumar

Anwesha Borthakur

Table of Contents

Cover image

Title page

Copyright

Contributors

Chapter 1. Bioremediation: a sustainable approach for management of environmental contaminants

1. Introduction

2. Application of bioremediation for environmental pollutants cleanup

3. Conclusion

Chapter 2. Pollution status and biodegradation of organophosphate pesticides in the environment

1. Introduction

2. Organophosphates and other pesticides

3. Effect of pesticides

4. Toxicological mechanism of organophosphates

5. Status of organophosphate pesticide pollution

6. Degradation of organophosphate pesticides

7. Conclusion

Chapter 3. Recent trends in the detection and degradation of organic pollutants

1. Introduction

2. Persistent organic pollutants: health effects and environmental chemistry

3. Method of POPs analysis (soil and water)

4. Methods for POPs degradation

5. Conclusions

Chapter 4. Phytoremediation of organic pollutants: current status and future directions

1. Introduction

2. The process of phytoremediation

3. Physiological and biochemical aspects of phytoremediation

4. Strategies of phytoremediation of organic pollutants

5. Role of enzymes

6. Role of plant-associated microflora

7. Fate and transport of organic contaminants in phytoremediation

8. Genetically engineered organisms for phytoremediation

9. Research and development in phytoremediation

10. Advantages and limitations of phytoremediation

11. Emerging challenges to phytoremediation

12. Conclusion

Chapter 5. Bioremediation of dyes from textile and dye manufacturing industry effluent

1. Introduction

2. Importance of characterization of dye-containing wastewater

3. Factors affecting biological removal of textile dyes

4. Microorganisms and mechanism involved in dye bioremediation process

5. Application of enzymes as biocatalyst in dye bioremediation

6. Advancements in bioreactor systems for dye remediation

7. Treatment of dye-containing industrial effluents using genetically modified microorganisms or enzymes

8. Current status of bioreactor application in CETPs of industrial areas for dye removal

9. Microbial fuel cell: a novel system for the remediation of colored wastewater

10. Potential of constructed wetlands for the treatment of dye-contaminated effluents

11. Conclusion and suggestions

Chapter 6. Mycoremediation of polycyclic aromatic hydrocarbons

1. Introduction

2. Mycoremediation: intact potential

3. Major enzymes

4. Biosurfactant production by fungi and its application in bioremediation

5. Factors affecting growth of fungi

6. Conclusion and future perspective

Chapter 7. Plant growth–promoting rhizobacteria and their functional role in salinity stress management

1. Introduction

2. Plant growth–promoting rhizobacteria

3. Plant growth–promoting rhizobacteria in salinity stress

4. PGPR and ACC deaminase activity

5. Conclusion

Chapter 8. Plant growth–promoting bacteria and their role in environmental management

1. Introduction

2. Plant growth–promoting bacteria

3. Xenobiotic compounds and their classification

4. Effect of xenobiotics on the health of human beings

5. Effects of xenobiotics on the plant growth

6. Future prospective

Chapter 9. Fungi as potential candidates for bioremediation

1. Introduction

2. Fungal bioremediation

3. Fungi in bioremediation

4. Technology advancement

Chapter 10. Cyanobacteria: potential and role for environmental remediation

1. Introduction

2. Conclusions and future perspectives

Chapter 11. An effective approach for the degradation of phenolic waste: phenols and cresols

1. Introduction

2. Treatment technologies for phenolic compound removal

3. Factors influencing bioremediation of phenolic waste

4. Limitations of biodegradation

5. Photocatalytic degradation

6. Factors affecting photocatalytic degradation of TiO2

Chapter 12. Environmental fate of organic pollutants and effect on human health

1. Introduction

2. Types of persistent organic pollutants

3. Conclusion

Chapter 13. Rhizospheric remediation of organic pollutants from the soil; a green and sustainable technology for soil clean up

1. Introduction

2. Organic contaminants in soil and their sources

3. Fate of organic pollutants in soil

4. Rhizoremediation: a conventional approach

5. Factors affecting rhizoremediation

6. Rhizoremediation potential, challenges, and future perspectives

Chapter 14. The role of scanning probe microscopy in bacteria investigations and bioremediation

Summary

1. Introduction

2. Bacterial biofilms

3. Scanning probe microscopy is a necessary tool in bioremediation investigations

4. Bacterial electromechanical biosensor

5. Scanning ion-conductance microscopy

6. Nanolithography

7. Scanning probe microscopy measurements of bacteria—manual

8. Methods

9. Conclusion

Abbreviations

Chapter 15. Research progress of biodegradable materials in reducing environmental pollution

1. Introduction

2. Biodegradable materials used for environmental protection

3. Conclusion

Appendix A: List of abbreviations

Chapter 16. Genetically engineered bacteria for the degradation of dye and other organic compounds

1. Introduction

2. Constructing genetically engineered microorganisms

3. Detection of genetically engineered microbes

4. Need of genetically engineered microbes

5. Dye degradation by engineered microbes

6. Organic contaminants degradation by genetically engineered microorganisms

7. Agent orange degradation by genetically engineered microorganisms

8. Organophosphate and carbamate degradation by genetically engineered microorganisms

9. Polychlorinated biphenyls degradation by genetically engineered microorganisms

10. Degradation of polycyclic aromatic hydrocarbons

11. Degradation of herbicide

12. Genetically modified endophytic bacteria and phytoremediation

13. Approaches to minimize the risks of genetically engineered microbes

14. Challenges associated with the use of genetically engineered microorganism in bioremediation applications

15. Factors influencing genetically engineered microorganisms

16. Regulation of genetically engineered microorganisms

17. Future perspective

18. Conclusion

Index

Copyright

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Contributors

Mohd Aamir,     Center of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, India

Arif Ahamad,     School of Environmental Sciences (SES), Jawaharlal Nehru University, New Delhi, India

Assel I. Akhmetova,     Advanced Technologies Center, Moscow, Russian Federation

Rahul Bhadouria

Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, India

Department of Botany, University of Delhi, Delhi, India

A.K. Bhatiya,     Department of Biotechnology, GLA University, Mathura, India

Muhammad Bilal,     College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China

Preetismita Borah,     CSIR-Central Scientific Instruments Organisation, Chandigarh, India

Anwesha Borthakur,     Leuven International and European Studies (LINES), Katholieke Universiteit Leuven, Belgium

Antra Chatterjee,     Molecular Biology Section, Centre for Advanced Study in Botany, Department of Botany, Banaras Hindu University, Varanasi, India

Mohd Ashraf Dar,     Department of Environmental Science, School of Earth Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India

Pooja Devi,     CSIR-Central Scientific Instruments Organisation, Chandigarh, India

Rajkumari Sanayaima Devi,     Deen Dayal Upadhyaya College (University of Delhi), New Delhi, India

Akanksha Gupta,     Institute of Environment & Sustainable Development, Banaras Hindu University, Varanasi, India

Shalini Gupta,     School of Environment and Sustainable Development, Central University of Gujarat, Gandhinagar, India

Deepak Gupta,     Institute of Environment & Sustainable Development, Banaras Hindu University, Varanasi, India

Garima Kaushik,     Department of Environmental Science, School of Earth Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India

Razia Khan,     Department of Microbiology, Girish Raval College of Science, Gujarat University, Gandhinagar, India

Zeenat Khan,     Environmental Genomics and Proteomics Lab, BRD School of Biosciences, Satellite Campus, Sardar Patel University, Vallabh Vidyanagar, India

Arvind Kumar,     State Key Laboratory of Cotton Biology, Key Laboratory of Plant Stress Biology, School of Life Science, Henan University, Kaifeng, Henan, PR China

Ajay Kumar,     Agriculture Research Organization (ARO), Volcani Center, Rishon LeZion, Israel

Cash Kumar,     Cytogenetics Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, India

Manish Kumar,     CSIR-Central Scientific Instruments Organisation, Chandigarh, India

Arun Kumar,     Bihar Agricultural University, Sabour, Bhagalpur, India

Sughosh Madhav,     School of Environmental Sciences (SES), Jawaharlal Nehru University, New Delhi, India

P.K. Mishra,     Department of Chemical Engineering and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi, India

Virendra Kumar Mishra,     Institute of Environment & Sustainable Development, Banaras Hindu University, Varanasi, India

Arpan Modi,     Agriculture Research Organization, Ministry of Agriculture and Rural Development Volcani Centre, Rishon LeZion, Israel

Dan Bahadur Pal,     Department of Chemical Engineering, Birla Institute of Technology, Mesra, Ranchi, India

Shilpi Pandey,     Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, India

Amit Kumar Patel,     Institute of Environment & Sustainable Development, Banaras Hindu University, Varanasi, India

Vipul Patel,     Environment Management Group, Center for Environment Education, Ahmedabad, India

Bhawana Pathak,     School of Environment and Sustainable Development, Central University of Gujarat, Gandhinagar, India

Deepak Pathania,     Department of Environmental Sciences, Central University of Jammu, District Samba, India

Priyanka,     Cytogenetics Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, India

Bhadouria Rahul,     Department of Botany, University of Delhi, New Delhi, India

Archana Rai,     Department of Molecular and Cellular Biology, Sam Higginbotom Institute of Agriculture, Technology and Sciences (SHIATS), Allahabad, India

Amit Ranjan,     Department of Kayachikitsa Institute of Medical Sciences, Banaras Hindu University, Varanasi, India

Divya Singh,     Center of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, India

Pardeep Singh,     Department of Environmental Science, PGDAV College, University of Delhi, New Delhi, India

Rajesh Kumar Singh,     Department of Dravyaguna, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India

Tripti Singh

Department of Biotechnology, GLA University, Mathura, India

Department of Chemical Engineering and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi, India

Sandeep Kumar Singh,     Center of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, India

Vipin Kumar Singh,     Center of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, India

Manoj Kumar Singh,     Department of Chemistry, Indian Institute of Technology Delhi, Hauzkhas, India

Rishikesh Singh,     Institute of Environment & Sustainable Development, Banaras Hindu University, Varanasi, India

Gurudatta Singh,     Institute of Environment & Sustainable Development, Banaras Hindu University, Varanasi, India

Raghwendra Singh,     Crop Production Division, ICAR-Indian Institute of Vegetable Research, Varanasi, India

Prashant Kumar Singh,     Agriculture Research Organization, Ministry of Agriculture and Rural Development Volcani Centre, Rishon LeZion, Israel

Pratap Srivastava

Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, India

Shyama Prasad Mukherjee Government Degree College, Phaphamau, Prayagraj, India

Akhileshwar Kumar Srivastava,     The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel

Neha Srivastava,     Department of Chemical Engineering and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi, India

Manita Thakur,     Department of Chemistry, Maharishi Markandeshwar University, Solan, India

Kangming Tian,     Department of Biological Chemical Engineering, College of Chemical Engineering and Materials Science, Tianjin University of Science and Technology, Tianjin, China

Dhanesh Tiwary,     Department of Chemistry, Indian Institute of Technology (IIT-BHU), Varanasi, India

Sachchidanand Tripathi,     Deen Dayal Upadhyaya College (University of Delhi), New Delhi, India

Ruchita Tripathi,     Department of Dravyaguna, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India

Juan Francisco Villareal Chiu,     Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Laboratorio de Biotecnología. Av. Universidad S/N Ciudad Universitaria, San Nicolás de los Garza, Nuevo León, Mexico

Wang Wenjing,     State Key Laboratory of Cotton Biology, Henan Key Laboratory of Plant Stress Biology, School of Life Science, Henan University, Kaifeng, Henan, China

Deepanker Yadav,     Department of Vegetable and Fruit Science, Institute of Plant Science, Agriculture Research Organization (ARO), The Volcani Center, Rishon LeZion, Israel

Igor V. Yaminsky,     Lomonosov Moscow State University, Moscow, Russian Federation

Chapter 1

Bioremediation

a sustainable approach for management of environmental contaminants

Pardeep Singh¹, Vipin Kumar Singh², Rishikesh Singh³, Anwesha Borthakur⁴, Sughosh Madhav⁵, Arif Ahamad⁵, Ajay Kumar⁶, Dan Bahadur Pal⁷, Dhanesh Tiwary⁸, and P.K. Mishra⁹     ¹Department of Environmental Science, PGDAV College, University of Delhi, New Delhi, India     ²Center of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, India     ³Institute of Environment & Sustainable Development, Banaras Hindu University, Varanasi, India     ⁴Leuven International and European Studies (LINES), Katholieke Universiteit Leuven, Belgium     ⁵School of Environmental Sciences (SES), Jawaharlal Nehru University, New Delhi, India     ⁶Agriculture Research Organization (ARO), Volcani Center, Rishon LeZion, Israel     ⁷Department of Chemical Engineering, Birla Institute of Technology, Mesra, Ranchi, India     ⁸Department of Chemistry, Indian Institute of Technology (IIT-BHU), Varanasi, India     ⁹Department of Chemical Engineering and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi, India

Abstract

The release of various inorganic and organic chemicals from various industries such as petrochemicals, textiles, pharmaceuticals, agro-based industries, and tanneries is highly toxic to the environment and human health. Several processes and technologies such as physical, chemical, and advanced oxidation processes are available for treatment of these pollutants. However, these processes and technologies have their own limitations and the end products are also of toxic nature. Therefore, there is a need for identifying and exploring sustainable and eco-friendly methods which require a lesser amount of chemicals, are economically feasible, and produce nontoxic end products.

The bioremediation approaches to clean up environmental pollutants are considered as emerging and sustainable methods recently. Bioremediation process is based on an integrated approach employing microbial communities such as actinomycetes, bacteria, fungi, and earthworms. It is considered as a sustainable process for management of organic pollutants-rich solid wastes and wastewater. Many microorganisms metabolize toxic chemicals to produce CO2 or CH4, water, and biomass. These pollutants may be enzymatically altered to metabolites that are less noxious or innocuous. Moreover, the solid residue generated in this process has been found to have a potential influence on soil macro- and micronutrients, indicating its application as organic manure. However, bioremediation technique required more research for its establishment at a larger scale with an emphasis on the environmental consequences of the end products. In this chapter, we have performed a literature survey based on biological methods for the management of organic pollutants. Microbes responsible for degradation processes have also been presented in the later part of the chapter. In this chapter, a thorough understanding of the bioremediation processes and methods applied for abatement and remediation of organic pollutants has been described in detail.

Keywords

Biodegradable wastes; Bioremediation; Organic matter; Sustainability

1. Introduction

Polluted soil resulting from industrial or agricultural processes poses serious health hazards to humans and animals and thus can have damaging consequences on the ecosystems by making land inappropriate for cultivation and other fiscal purposes. Various industries such as carpet, textile, and petrochemical production create intensive problems in the natural environment by disposing toxic wastes on one hand and generating a huge quantity of waste, oily sludge, and petroleum waste enriched soil on the other hand, which constitutes a major confront for hazardous waste management (Farhadian et al., 2008). Apart from this, oil shipping is also one of the key causes of environmental contamination where the land and water gets polluted because of the oil spill, ship breakage, and seepage of oil pipelines.

The economically viable and environmentally feasible management of industrial sludge is a major concern worldwide. For disposal of industrial sludge, globally adopted technologies comprise of landfilling, high-temperature drying, sludge spreading on land surface, lime added stabilization, burning, and composting. Because of excessive expenditure on sludge management, the majority of textile industries in India generally released their wastewater effluents in the farming fields, open dumps, fallow land, and ineffectively controlled sanitary landfills and alongside the railway tracks. It further contaminates groundwater causing serious human health hazards. Meanwhile, low availability of landfill area, rigorous national wastes discarding policy, and local people awareness have caused landfilling and land spreading highly costly and impractical. The sludge management practices in most of the developing countries are not well developed. Currently, several factories and municipalities are working on environment-friendly and low-cost sludge treatment practices. Thus, it is imperative to mitigate toxic environmental contaminants for sustainable development (Kümmerer et al., 2019).

A number of physical and chemical methods are currently being employed at large scale for municipal wastewater management chiefly based on sewage treatment plants (STPs). In addition to building expenses, upholding troubles in treatment plants has raised the query of sustainability. Furthermore, surplus sewage sludge formed by these treatment plants has posed more severe confines on release during the previous few decades (Vigueros and Camperos, 2002). Several developing countries cannot meet the expense of construction of STPs, necessitating the development of some eco-friendly and economically feasible machinery for in situ wastewater management. Under such critical conditions, a few eco-friendly techniques can resolve the limitations linked with secure and economically efficient wastewater management machinery.

Bioremediation is an emerging and innovative technology because of its economic feasibility, enhanced competence, and natural environment friendliness. The technology uses various eco-friendly microbial processes to handle the ever-rising environmental pollution problem. In such approaches, microbes adjust themselves against noxious wastes and environmentally adapted microbial strains grow naturally, which subsequently convert a wide variety of toxic chemicals into nontoxic forms. The microbial degradation of xenobiotics is based on enzyme activities. It further includes rhizoremediation, phytoremediation (McCutcheon and Jørgensen, 2008; Chang et al., 2009), and vermicomposting depending on the biological activities involved. Phytoremediation is based on plant-assisted extenuation of pollutant concentrations at the contaminated sites, whereas rhizoremediation includes the elimination of specific pollutants from impure sites by the mutual interface of plant roots and appropriate microbial flora (Rajkumar et al., 2012). Because bioremediation appears to be a promising substitute to conventional cleanup machinery, extensive research is being carried out in this field. Vermicomposting and vermifiltration are natural waste management procedures relying on the utilization of worms to change organic wastes to form soil-enriching compounds (Vettori et al., 2012). Domestic wastewater and industrial sludge management can be accomplished through these processes in a sustainable way (Benitez et al., 2002). In addition, a substantial decrease in pathogens has been observed up to the end-products level. Therefore, it can be securely used for land application. Biological methods have been reviewed and acknowledged for remediation of environmental pollutant. In this chapter, we have tried to focus on the application of biological methods which were used for effective waste treatment. Several different strategies of bioremediation have also been discussed in later sections.

2. Application of bioremediation for environmental pollutants cleanup

In previous decades, rapid industrialization, urbanization, and indiscriminate resource utilization by ever-increasing human population have increased the contamination of atmosphere, land surfaces, and ground and surface waters. The wide-scale degradation of natural resources constitutes a major threat to public health around the globe. Majority of contaminants affecting soil and water system are heavy metals, pesticides, petroleum hydrocarbons, and large amount of toxic industrial effluents. These xenobiotics of anthropogenic origin are recalcitrant in nature.

In the current scenario, restoration of degraded land, water, and soil system is only possible by sustainable and eco-friendly processes. Among the various recent processes being used for the abatement of environmental pollution, bioremediation is recognized as an emerging methodology for the restoration of polluted environments. However, its ground level applicability is restricted because of different climatic factors. Various microbes degrade recalcitrant pollutants under aerobic or anaerobic conditions through complete mineralization or cometabolism by using pollutants as their carbon sources. Bacteria and fungi have been reported as favorable and potential candidates for both in situ and ex situ degradation of organic pollutants present at contaminated sites. Furthermore, the microbes can be genetically engineered for efficient degradation of environmental contaminants. Nevertheless, extensive political and ethical concern restricts the wide-scale applicability of genetically engineered organisms. The current biotechnological progress such as the use of proficient microbial consortia, indigenous microbes, application of specific enzymes, biosurfactant, and rhizoremediation are the new prospects in bioremediation technology. A schematic representation of various methods and techniques applied for bioremediation of different inorganic and organic contaminants has been illustrated in Fig. 1.1.

2.1. Bioremediation strategy for hydrocarbon contaminated water and soil

Bioremediation of hydrocarbon polluted soils and groundwater using bacteria has gained immense consideration recently. Bacteria can degrade a large number of toxic hydrocarbons under both aerobic and anaerobic circumstances. Benzene, toluene, ethyl benzene, and xylene (BTEX) compounds are typical examples of hydrocarbons and are carcinogenic (de Graaff et al., 2011) and neurotoxic in nature. Moreover, Environmental Protection Agency (EPA) classified these hydrocarbons as priority pollutants requiring strict regulation. When organic contaminants such as BTEX are released into the environment (Jin et al., 2013), the function and structure of the microbial communities are generally affected. Although significant researches on biodegradation of BTEX components by bacteria (Li et al., 2012) have been reported, however, most of the studies have concentrated on the degradation of only one or two components by bacterial isolate (Table 1.1). Furthermore, it is recognized that the biodegradation efficiency of one compound in a mixture can be influenced by additional components. The side effect generated through the deprivation of one particular compound can also influence the deprivation of another compound. Therefore, it is imperative to use an integrated bioremediation approach by using the consortium of microbes for degradation of petrochemicals containing hydrocarbons.

Figure 1.1  Different strategies (A) and methods (B) of bioremediation of various inorganic and organic contaminants.

Table 1.1

2.2. Bioremediation of heavy metal contaminated water

Bioremediation of heavy metal enriched soils and groundwater illustrates an immense perspective for upcoming improvement because of its environmental compatibility and probable expenditure efficiency (Baceva et al., 2014). It relies on microbial actions to diminish, mobilize, or immobilize noxious heavy metals through biosorption, biovolatilization, precipitation, surface complexation, and oxidation–reduction processes (Paul et al., 2014; Teixeira et al., 2014). Microorganism-directed oxidation–reduction reactions involving organic carbon, iron, manganese, and sulfur are the basic mechanisms influencing heavy metals mobility. Under natural environmental conditions, there exists a complicated interface among heavy metal pollutants and interacting microbes. These microorganisms have evolved specific resistance mechanism that permits their existence (Luo et al., 2014) under heavy metal enriched conditions. These microbes are efficient to alleviate the concentration of metal contaminants in their vicinity. Microorganisms are observed to proficiently eliminate dissolved and suspended metals, particularly from a medium having very low concentrations through bioaccumulation, surface complexation, and biosorption; therefore, methods relying on microbial process offer a substitute to the conservative practices of metal remediation (Dundar et al., 2014). Microbes reported for management of heavy metals are tabulated in Table 1.2.

2.3. Bioremediation of dye contaminated water

Dyes are used for the permanent coloring of fibers and other consumer products including foods, cosmetics, pharmaceuticals, papers, etc. The annual production of these dyes is more than 7  ×  10⁷ tons, out of which 30,000–150,000 tons are discharged into water (Anjaneya et al., 2011). In textile processing industries, a broad range of structurally varied dyes are utilized, and therefore, effluents from these industries are tremendously erratic in composition. In general, wastewater generated from dyeing industries contains up to 50% dye of the originally used concentration, together with several other chemical components, dispersing agents, fixatives, heavy metals, and inorganic salts. Generally, dyes are visibly detectable at very low quantity (1  mg  L−¹), which may cause water pollution and changes to normal functioning of aquatic ecosystem by reducing dissolved oxygen contents, due to reduced photosynthetic activity of submerged plants caused by very weak penetration of light into water imposed by dyes. Hence, the toxicity exerted by textile effluents due to synergistic actions of physical appearance and chemical constituents is raising an environmental concern for their minimization to permissible limits. It is identified that 90% of reactive dyes get their way into treatment plants that may remain unaffected and released as such into rivers (Abadulla et al., 2000). Several dyes presently being utilized are not susceptible to degradation or elimination with physicochemical methods. Most importantly, often the degradation by-products of physicochemical methods are even more noxious than the parent dye used. Color can be eliminated from wastewater by chemical and physical processes including adsorption, precipitation, flocculation, and oxidation followed by filtration and electrochemical methods. These techniques are relatively expensive and have operational troubles (Kapdan et al., 2000). Numerous troubles, particularly the high dose requirement of chemicals and extensive power consumption, limit their realistic purpose. Consequently, the biodegradation of synthetic dyes has gained rising magnetism because of its natural ecological resemblance, lesser treatment costs, and elevated efficiency.

Currently, several scientific groups across the world are involved in manipulating the bacterial genetic constitution to improve their dye degradation ability to accelerate the bioremediation process. Different microbial consortium can degrade numerous azo-dyes aerobically and anaerobically. Actually, bacterial consortia are supposed to be more beneficial for complete dye degradation. In mixed culture, the toxic intermediates generated because of the activity of one bacterium are degraded by other bacteria of consortium (Forgacs et al., 2004; Jain et al., 2012). Thus, the degradation of dye will depend on origin and chemical nature of dyes and microorganism used in the consortium.

Table 1.2

2.3.1. Bioremediation approaches used for dye degradation

Dye decolorization is started by anaerobic reduction reaction performed by azo-reductases or azo-bonds breakage under aerobic or anaerobic condition leading to the formation of aromatic amines because of physiological and biochemical activities of the mixed bacterial community (Sponza and Isik, 2004). A list of microorganisms involved in dye degradation is presented in Table 1.3.

A detailed description on various processes for dye degradation has been presented below:

2.3.1.1. Aerobic treatment

Reports on bacterial degradation of azo-dyes are very limited; however, some microorganisms have shown their capacity of dye reduction. Pseudomonas aeruginosa has been demonstrated to degrade commercially exploited textile and tannery dye Navitan Fast Blue SSR in a medium amended with glucose as a carbon source under aerobic condition (Garg and Thripathi, 2017). Kalyani et al. (2009) have also observed that some bacterial strains have capability to degrade dye under the aerobic environments.

Table 1.3

2.3.1.2. Anaerobic treatment

Under anaerobic condition, azo-dye reduction is achieved by breakage of the azo-bonds. Under the anaerobic situation, cleaving of dyes occurs, which produces toxic aromatic amines by bacterial metabolism (Bhatt et al., 2005).

2.3.1.3. Anoxic treatment

Anoxic degradation of different dyes by facultative anaerobic and mixed aerobic microorganisms is reported in different studies (Kapdan and Alparslan, 2005). Although several microorganisms are capable of growing under aerobic condition, however, the dye is degraded only under anoxic environments. Several pure bacterial cultures including those of Pseudomonas luteola, Aeromonas hydrophila, Bacillus subtilis, and Proteus mirabilis are known to anoxically degrade azo-dyes (Sandhya et al., 2005).

2.3.1.4. Sequential degradation of dyes

It has been suggested that aromatic amines produced after anaerobic degradation of azo-dyes can be despoiled subsequently under aerobic environment. The applicability of this approach was firstly proven for Mordant Yellow, a sulfonated azo-dye. After aeration, complete mineralization of amine by microbial activities is observed.

2.4. Vermi-biofiltration of wastewater

Vermi-biofiltration is a natural waste management method relying on worms to alter organic wastes to form soil enriching compounds (Romero et al., 2006). Domestic wastewater and industrial sludge management can be lodged through these methods in a sustainable way (Solis-Mejia et al., 2012). A substantial decrease in pathogens has been observed in the final product to a level that can be securely useful to land (Najar and Khan, 2013). The practice can be used at small scale for organic waste handling or municipal waste management (Karmakar et al., 2012). Vermi-biofiltration is a method that acclimatizes conventional vermicomposting method into an inert wastewater handling procedure by means of epigeic earthworms (Garg et al., 2009; Gupta and Garg, 2009). According to Komarowski (2001), vermi-biofiltration scheme uses suspended solids that are placed on an upper portion of a filter and developed by earthworms and feed to soil microorganisms harnessed in vermifilter. The solubilized and non-soluble organic and inorganic suspensions are removed by adsorption and stabilization process through multifaceted degradation reactions that occurs in soil occupied by aerobic microorganisms and earthworm. In general, acclimatized vermibed earthworms collect numerous organic contaminants in the vicinity of surrounding soil system (Sangwan et al., 2008) through passive absorption by body wall and also by intestinal uptake during the course of soil passage via gut (Mahmood et al., 2013).

2.5. Bioremediation of pesticide contamination

The annual global utilization of pesticides is approximately 2 million tonnes, of which 24% is used by the United States, 45% in Europe, and rest 25% by remaining parts of the world. India is reported to consume about 3.8% of the total pesticide produced worldwide. The pesticide consumption for agricultural applications is 0.5, 6.6, and 12.0  kg  ha−¹ for India, Korea, and Japan, respectively (Gupta, 2004). Earlier, the pesticide application, as anticipated, was quite helpful in reducing crop yield loss happening because of insect pest attack and thus opened the way for enhancement in crop productivity. However, extensive application of chemically synthesized pesticides has given rise to contamination of the natural environment and also caused several chronic impacts on human society (Bhanti and Taneja, 2007). The stable nature, long-term existence in the natural environment, biological magnification, and accumulation at various trophic levels due to their lack of selectivity, and organochlorines have been reported to be responsible for pest resistance development and hazardous effect on nontarget organisms (Carson, 1962). The possible threats to all living organisms arising from the indiscriminate application of these agricultural chemicals have now emerged as one of the most potent environmental or health problems particularly in Third World countries. Pesticides are mainly criticized for their availability in drinking water, vegetables, mammalian blood, human food, milk products, fat samples, and other food commodities. There is no contradiction regarding the human health hazards associated with the application and chronic exposure to pesticides. Hence, the presence of pesticide residue in different environmental samples via contaminated food chain is a direct indication of acute or chronic exposure and average body risk to persistent pesticides.

2.6. Removal of pharmaceutical and personal care products by biological degradation processes

Microorganisms are known to degrade the environmental pollutants by using the contaminants for their vital physiological and biochemical processes, and under certain conditions, different microbes can coordinate each other to degrade the pollutants. The following subsections represent the role of pure and mixed culture in biodegradation of pharmaceutical and personal care products (PPCPs).

2.6.1. Pure cultures

Several experimental investigations have demonstrated that pure cultures of numerous algae, bacteria, and fungi obtained from different samples including activated sludge, wastewater, or sediment can be utilized to treat the commonly detected pollutants such as iopromide (Liu et al., 2013), carbamazepine (Popa et al., 2014), ibuprofen (Almeida et al., 2013), sulfamethoxazole (Jiang et al., 2012), diclofenac (Hata et al., 2010), paracetamol (Dang et al., 2013), and triclosan (Zhao et al., 2013). The pure cultures of different organisms efficient in degradation of various PPCPs have been presented in Table 1.4. A few pure cultures obtained from activated sludge showed efficiency in removal of a number of PPCPs. For example, Achromobacter denitrificans is able to mineralize sulfamethoxazole and other sulfonamides (Reis et al., 2018). Apart from this, several pure cultures can consume specialized PPCPs as sole source of C and energy, though with changed degradation pathways (Dang et al., 2013; Almeida et al., 2013). For example, Delftia tsuruhatensis, P. aeruginosa, and Stenotrophomonas can mineralize paracetamol. The study concluded that D. tsuruhatensis and P. aeruginosa contributed very less in paracetamol removal, while biosorption by Stenotrophomonas contributed significantly in removal of paracetamol. The differences could be due to involvement of different enzymes participating in degradation. Sometimes pure cultures are unable to utilize few PPCPs as carbon and energy source because of their substrate specificity. Under such conditions, other substrate needs to be amended in medium to fulfill the requirement of carbon and energy source so as to maintain the vital metabolic activities at optimal rate. For instance, the stable nature of carbamazepine often does not allow the efficient degradation by microbes. But, mixed consortium consisting of an unidentified basidiomycete member (Santoso et al., 2011) and Streptomyces MIUG (Popa et al., 2014) was noticed to breakdown the carbamazepine in medium supplemented with glucose. Along with carbamazepine, iopromide was also susceptible to degradation after additional substrates were amended in the medium. Liu et al. (2013) demonstrated that Pseudomonas sp. I-24 bears the ability to degrade iopromide with starch as primary supplement. Diclofenac has been reported to display high resistance to biological degeneration in activated sludge system. However, Hata et al. (2010) showed that white-rot fungi is capable to fully remove diclofenac to the safety limits prescribed for the organisms without any added supplement. The microbial enzyme activation has been suggested as another important factor leading to PPCPs degradation. The biological breakdown of PPCPs relies on whether microbes are able to synthesize the essential enzymes responsible for degradation. For example, triclosan is known to stimulate Nitrosomonas europaea to synthesize ammonia monooxygenase to facilitate fast degradation of triclosan (Roh et al., 2009). However, few PPCPs including ciprofloxacin, tetracycline, and trimethoprim do not readily stimulate microbes to synthesize the specific enzyme, thus, leading to inefficient biodegradation. Most importantly, there is no report on contribution of any pure culture isolated so far in decomposition of ciprofloxacin, tetracycline, and trimethoprim. Therefore, to facilitate the effective biodegradation of hazardous recalcitrant PPCPs, the primary requirement is to stimulate the microorganisms with the ability to produce the specific degradative enzyme in a given environmental condition.

Table 1.4

2.6.2. Mixed cultures

Mixed cultures are more efficient in biological degradation of the PPCPs as compared to pure cultures because under some environmental conditions it is very hard to isolate the pure culture. Limited study has been performed to analyze the efficiency of mixed culture for PPCPs removal (Khunjar et al., 2011). Mixed culture has the efficiency to remove PPCPs. Khunjar et al. (2011) described the role played by mixed culture of heterotrophic and ammonia-oxidizing bacteria for enhanced elimination of 17a-ethinylestradiol. Actually, the commonly employed biological treatment methods rely on synergistic actions of mixed cultures to eliminate PPCPs. However, sometimes activated sludge demonstrates low PPCPs elimination rate. Therefore, experiments have been carried out to enhance the PPCPs degradation through activated sludge process. High rate removal of PPCPs through metabolic activities of mixed culture present in activated sludge has been described by Zhao et al. (2013). Interestingly, mixed culture has been reported to facilitate very fast decomposition of mixed PPCPs as compared to degradation of a single PPCP (Vasiliadou et al., 2013). This can be explained by the fact that few members of mixed PPCPs can serve as C and energy source for mixed culture, thus facilitating further degradation of other PPCPs. Hence, mixed cultures have been proposed as a potential alternative for accelerated degradation of PPCPs.

2.6.3. Activated sludge process

Activated sludge technique has been largely employed for biological treatment in traditionally used wastewater treatment plants. The PPCPs degradation in biological treatment has been attributed to the combinatorial action of volatilization, surface binding, and microbial decomposition. However, the role of volatilization and adsorption processes in degradation of PPCPs is minimal (Li et al., 2015). Generally, volatilization happens simultaneously with aeration. The adsorption of PPCPs during biological treatment is significantly affected by physicochemical attributes of compounds to be degraded. Furthermore, changes in environmental variables including pH, oxygen content, temperature, the composition of the microbial community, and nutrient status can also largely influence the overall efficiency of activated sludge system applied for PPCPs elimination. Biodegradation is suggested as the major phenomenon responsible for PPCPs elimination in activated sludge process. Therefore, to improve the degradation of PPCPs, an effective strategy must be adapted to increase the decomposition. Nevertheless, microbial decomposition is not always efficient in the elimination of environmental contaminants due to the low abundance of microbes responsible for degradation. These impediments can be resolved by prior acclimatization to contaminants, bioaugmentation (Wang et al., 2004) and biostimulation. Through adaptation and bioaugmentation, the abundance of the pure or mixed culture of microorganisms effective in contaminant degradation can be improved in biological treatment methodologies. Plosz et al. (2012) have designed a model for xenobiotic trace chemicals and utilized it to forecast and monitor the environmental factors affecting the elimination of carbamazepine and diclofenac in activated sludge system.

2.7. Vermicomposting of solid wastes

Disposal of industrial solids is becoming a solemn crisis. The indecent and arbitrary discarding of industrial solids is posing an immense challenge to India and other rising countries. They cause odor difficulty and are the probable cause of surface and groundwater contamination. The sludge resulting from diverse industrial actions and wastewater handling plants is managed through unsuitable modes such as landfilling and incineration (Hashemimajd et al., 2006). The inadequate landfill areas, more severe national waste discarding rules, and local awareness have complicated the landfilling even more costly and unfeasible. Taking into consideration all the troubles of waste management, vermicomposting is one of the sustainable modes to degrade the solid and human wastes (Lalander et al., 2013). Furthermore, vermicomposting also alters the waste into compost, which is additionally used as plant nutrients (Gomez-Brandon et al., 2013). Vermicomposting is, therefore, suggested for the management of a broad variety of organic wastes and the production of organic matter rich in soil amendments (Lleo et al., 2013).

2.8. Genetically engineered microorganism–based bioremediation

Presently, several scientific groups across the world are involved in manipulating the bacterial genetic constitution for removal of man-made pollutants. Genetically engineered organisms offer the possibility of degradation of a range of pollutants (Dronı́k, 1999). They have exhibited bioremediation potential in the management of polluted soil and groundwater system as well as activated sludge environments along with better degradation capabilities for a number of chemical and petrochemicals pollutants (Sayler and Ripp, 2000). Recently, various microorganisms and enzymes have been engineered for biodegradation of polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and persistent organic pollutants (Ang et al., 2005). However, environmental concerns and regulatory constraints limit their large-scale in situ applications (Pandey et al., 2005). Although several experiments dealing with bioremediation have been carried out under in vitro conditions, it has always been too complicated to investigate the fate, behavior, and removal rate of contaminants in the natural ecosystem because of the involvement of varied environmental factors including biosafety (Singh et al., 2011).

2.9. Factors affecting bioremediation with emphasis on petrochemical and other organic pollutants

Bioremediation of petrochemical hydrocarbon contaminated soil and water is a complex process due to their noxious and hydrophobic behavior and multiphasic nature, diversity of microbial