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Emerging Pollutants Remediation Water Systems
Biomass-Based Technologies

CHAPTER MENU

1. 1.1 Introduction
2. 1.2 Adsorption-Based Remediation
   1. 1.2.1 Biomass
   2. 1.2.2 Terrestrial and Marine Bioresources
   3. 1.2.3 Agro-Industrial Wastes
   4. 1.2.4 Activated Carbons (ACs)
   5. 1.2.5 Bioresources
   6. 1.2.6 Agro-Industrial Wastes
   7. 1.2.7 Activated Sludge (AS)
3. 1.3 Bioremediation
   1. 1.3.1 Phytoremediation
   2. 1.3.2 Constructed Wetlands (CWs)
   3. 1.3.3 Microbial Remediation
   4. 1.3.4 Biocoagulants and Bioflocculants
4. 1.4 Multi-Element Water Treatment Process
   1. 1.4.1 Membrane Bioreactors (MBRs): Biodegradation and Membrane Filtration
   2. 1.4.2 Activated Carbon and Ozone
5. 1.5 Views and Recommendations
6. 1.6 Conclusion

1.1 Introduction

Emerging Pollutants (EPs) or pollutants of emerging concern are labels for a class of chemicals that are intrinsically detrimental to the environment but not essentially lethal [1]. This assemblage of chemicals incorporates an extensive assortment of substances including human and veterinary drugs, personal care products (PCPs), disinfection by-products (DBPs), polycyclic aromatic hydrocarbons (PAHs), perfluorinated compounds (PFCs), heavy metals, surfactants, pesticides, flame retardants, algal contaminants and hormones besides numerous other groups of chemicals. Throughout the preceding few decades, several investigative programmes have been going on to explore and examine the existence and fate besides ecotoxicology, of a lot of emerging pollutants (EPs). The EPs are sampled out from soils [2], sediments [3], wastewaters plus other aquatic environs [4]. As far as distribution of EPs is concerned traces of these have been reported from practically all the domains of our environment [5]. These EPs have also been found in the bodies of newborn infants proving their grave peril to the well-being of humans and other organisms alike. Normal treatment procedures are incompetent to eliminate these EPs, resulting in their discharge into receiving aquatic environments. However, a thorough and all-encompassing scientific research concentrated on the investigation of EPs source, presence, effects; and its treatment methods are not well established [6].

EPs are highly reactive and mobile due to which its elimination from aquatic settings is often an uphill task. It is pertinent to mention that minute quantities of EPs can pollute a significant bulk of aquatic ecosystems. Furthermore, EP-laden wastewaters can't be efficiently treated by already existing treatment operations which results in an augmented jeopardy due to their persistence in the environs [7, 8]. Consequently, the existence of EPs in wastewater management facilities is gradually developing into an unintended birthplace of severe contamination hazard to the waterways. Therefore, developing state-of-the-art procedures for management of waters tainted with EPs is an unrelenting and everlasting requisite. In this concern, a number of techniques have been explored and developed for eliminating and mitigating the deleterious effects of EPs on aquatic ecosystems through various physical, chemical and biological approaches. Certain methods are working well, however are costly, while other methods are equally capable and economical but detrimental to the environment. In this backdrop, water management techniques using biomass and related derivatives as a chief element are prospective of remediating the predicament of a number of EPs (Table 1.1). The biomass-based technologies are more efficacious, economical as well as eco-friendly as compared to existing treatment methods. This chapter delivers an overall gist of diverse pioneering biological methods for eliminating an array of EPs as well as outlining forthcoming exploration trends.

Table 1.1 Biosorption of varied biomasses to eliminate certain EPs from contaminated environments.

• Paracetamol
• Metronidazoles

Sugarcane bagasse

Siris seed pods

[9]

[10]

Endocrine-disrupting chemicals

Nonylphenol

• Uranium VI
• Cesium

Wheat straw

Citrobacter freudii (bacteria)

Fusarium Sp. (fungi)

Basil seeds

Walnut shells

[12]

[13]

[14]

[15]

[16]

• Microcystin-LR

1.2 Adsorption-Based Remediation

This water treatment method characterizes a vital part of EP remediation systems. Four major processes are discussed here, viz. sorption, adsorption, biosorption and bioadsorption. The terms adsorption and adsorbent refer to the sorbing substances that aren't biomass-based. This involves activated carbons and biopolymers (biomass derivatives), as well as silica, zeolites, clays and synthetic polymers. The terms biosorption and biosorbent (raw or pretreated) encompass the application of dead ("bioadsorption") and standing biomass ("passive" biosorption and/or "active" bioaccumulation).

1.2.1 Biomass

Several types of biosorbents "plants, algae, bacteria, fungi, yeasts" have been quantified in the sources over many years due to their potential for eliminating diverse toxic pollutants. Although EPs are discovered in diverse environments and pose a number of severe undesirable effects on our planet, they aren't presently counted in standard environmental assessment options. There exists a knowledge gap concerning the level of research conducted on the already existing pollutants and the newly emerging pollutants. A scientific supposition stating that conventional contaminants hold greater and confirmed toxicity threat in contrast to the EPs isn't correct at all times. In fact, during the last few years research investigations vis-à-vis EPs have increased exponentially [18].

1.2.2 Terrestrial and Marine Bioresources

Azoimide (hydrazoic acid) is an extremely toxic substance polluting hospital wastes [19]. In order to find a viable way out to deal with this toxic substance, its removal by powdered almond integument from contaminated waters was carried out. It was found that 1 g of almond biomass removed 45 mg of the azoimide toxin [20]. The release of hazardous wastes from nuclear power plants has been a serious cause of concern. To find a solution, investigators explored the adsorption efficacy of cactus fibers (Opuntia ficus) to get rid of uranium VI from discharged nuclear wastes and they were quite successful in it [21]. Similarly, the potential of Posidonia oceanica for removing surfactants from aqueous solutions was evaluated. The marine algae Padina pavonia was used as a biosorbent for the remediation of uranium (VI) from wastewaters. It was discovered that the marine biomass was effective in eliminating uranium with 98% effectiveness [22].

1.2.3 Agro-Industrial Wastes

In Turkey, the biosorption of Gallium III from polluted waters was accomplished via tea waste. It was discovered that this tea waste was effective in removing 77.4% of waste present in the solution [23]. Rice straw was utilized as a biosorbent to eliminate pharmaceuticals [24] which are often identified in wastewaters [25]. The findings confirmed that rice straw was able to remove the pharmaceuticals by means of adsorption. Similarly, a research group from Brazil was successful in removing Diclofenac from aqueous solutions via Isabel grape bagasse [26].

1.2.4 Activated Carbons (ACs)

1.2.5 Bioresources

Various biological precursors are used for manufacturing extremely absorbent activated carbons which can further be used for tackling EPs. An innovative AC was manufactured using Artemisia vulgaris for removing the widely used drug Ibuprofen from aqueous solutions. It was established that A. vulgaris-derived AC removed 17 mg/g of the drug [27]. ACs have also been produced from the leaves of the date palm (Phoenix dactylifera). The ACs formed from it were used for elimination of an antibiotic, ciprofloxacin, from contaminated waters [28].

1.2.6 Agro-Industrial Wastes

Chemically activated biochar formed from loblolly pine chips was used for the adsorption of several EPs from contaminated waters. The adsorption findings revealed an enhanced capacity for removing EPs [29]. In another investigation researchers examined the potential of ACs made from sesame stalk derived for removing Phenanthrene. The adsorbent displayed a remarkable efficacy to remove this EP [30].

1.2.7 Activated Sludge (AS)

Activated sludge is often useful in wastewater management plants. Huge quantities of AS are generated regularly, therefore...