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Nanotechnology-Associated Bioremediation for the Elimination of Emerging Contaminants
Published in S Rangabhashiyam, V Ponnusami, Pardeep Singh, Biotechnological Approaches in Waste Management, 2023
Alok Tripathi, Sheeba Narayanan, P. Suresh Kumar
The secondary wastewater treatment process is also known as the biological treatment which is used to remove organic contaminants present in wastewater through microorganisms (Verlicchi et al., 2012). Secondary treatment has been classified into two categories, the first is the aerobic treatment where the microorganisms use oxygen to degrade organic matter present in wastewater, and the second is the anaerobic treatment where the organic contaminants are treated by microorganisms in absence of oxygen. Activated sludge process is an example of a combined aerobic and anaerobic system (Bora and Dutta, 2014). The final stage of wastewater treatment is tertiary treatment, which is used to enhance the quality of water before its discharge. It includes the advanced processes to remove residual organic, inorganic, and microorganisms leftover in primary and secondary processes. It includes filtration, chemical treatment, and ozonation (Qu et al., 2013).
Urban water quality and chemical pollution
Published in Thomas Bolognesi, Francisco Silva Pinto, Megan Farrelly, Routledge Handbook of Urban Water Governance, 2023
Serge Stoll, Stéphan Ramseier Gentile
Pollution in terms of untreated wastewater is one of the major risks to water quality, public health, and urban security if wastewater is not treated via wastewater treatment plants and then discharged properly in natural aquatic systems. Wastewater contains high amounts of inorganic and organic dissolved and suspended solid materials (concentrations in untreated sewage range from 100 to 350 mg/L) resulting in high turbidity. Moreover, pathogens are also present at very high concentrations. Furthermore, treated wastewater also contains large quantities of nutrients, such as ammonia and phosphorus, ranging, respectively, from 2 mg/L to 50 mg/L and from 1 mg/L to 20 mg/L.
World Water Crisis and Climate Change
Published in Stanley E. Manahan, Environmental Chemistry, 2022
Tertiary wastewater treatment (sometimes called advanced wastewater treatment) is a term used to describe a variety of processes performed on the effluent from secondary waste treatment, which may contain potentially harmful substances. The treatment of such wastewater before its release is especially important considering that a significant fraction of it may be taken in with a municipal water supply downstream. The contaminants removed by tertiary waste treatment fall into the general categories of (1) suspended solids, (2) dissolved organic materials, and (3) dissolved inorganic compounds. Low levels of substances and their metabolites, such as pharmaceuticals, synthetic and natural hormones, and personal care products that are discharged in sewage, pose challenges in advanced wastewater treatment because of their potential biological activity. Suspended solids are primarily responsible for residual biological oxygen demand in secondary sewage effluent waters. The dissolved organics are the most hazardous from the standpoint of potential toxicity. The major problem with dissolved inorganic materials is that presented by algal nutrients, primarily nitrates and phosphates. In addition, potentially hazardous toxic metals may be found among the dissolved inorganics.
A novel circular approach to analyze the challenges associated with micro-nano plastics and their sustainable remediation techniques
Published in Journal of Environmental Science and Health, Part A, 2023
Tejaswini Mssr, Pankaj Pathak, Lakhveer Singh, Deep Raj, D. K. Gupta
Secondly, despite the presence of advanced chemical treatment technologies for the removal of MNPs from wastewater are present, still, some percentage of MNPs is observed in the treated outlet. Although through membrane filter technology, one can effectively remove MPs with 90–99% efficiency, still some disadvantages are associated with it. For instance, fouling is considered the main drawback associated with conventional membranes. The pores of the membranes are often blocked or get deposited with nanoparticles. Interaction between NPs and membrane filters results in fouling and this can be reversible or irreversible.[57] However, through backwashing, 30–40% of NPs can be recovered. Since there is variation in the size of MNPs, the membrane is damaged at its ends leading to abrasion. In developed nations, like Canada, the wastewater after primary and secondary treatment is passed through a membrane bioreactor that removes the MNPs present in the treated effluent. However, this method involves high operational and maintenance costs. Tertiary treatment is the last step of wastewater treatment which mainly includes chlorination and UV oxidation. But, according to Kelkar et al.[80] chlorination results in cracking, thereby increasing the concentration of MPs in the water. Thus, wastewater plants are becoming the source of secondary MPs.
Removal of Organic Micropollutants from Treated Municipal Wastewater by O3/UV/H2O2 in a UVA-LED Reactor
Published in Ozone: Science & Engineering, 2022
Elisa Kerber Schoenell, Nikolai Otto, Marco Antônio Siqueira Rodrigues, Jörg Wolfgang Metzger
One of the main sources for OMPs in the environment is effluents of municipal wastewater treatment plants (WWTPs) (Brack et al. 2015; Hamza, Iorhemen, and Tay 2016; Luo et al. 2014; Pomiès et al. 2013; Richardson and Kimura 2017; Rizzo et al. 2019) because conventional treatment plants are not particularly designed for OMP removal and their elimination efficiency for these substances can be low. As a consequence, the discharge of treated urban wastewater leads to increasing concentrations of OMPs in waterbodies (Aquino, De, Brandt, and Chernicharo 2013; Grandclément et al. 2017; Hamza, Iorhemen, and Tay 2016; Jelic et al. 2011; Moreira et al. 2016; Postigo and Richardson 2014; Ribeiro et al. 2015; Rizzo et al. 2019; Silva et al. 2015; Tokumura et al. 2016: Wang and Wang 2016). This creates concerns due to their harmful effects on the aquatic environment and on human health, as well as needs to improve or supplement the conventional wastewater treatment processes by additional novel processes (Arola et al. 2017).
Biotechnique for nitrogen and phosphorus removal: a possible insight
Published in Chemistry and Ecology, 2020
Anne Bhambri, Santosh Kumar Karn
One important point source of nitrogen and phosphorus is the discharge from municipal wastewater treatment plants. Wastewater disposal has been a local public health and aesthetics issue [35]. To address these problems, municipal wastewater treatment methods were developed and implemented for the purpose of reducing the discharge of contaminants and pathogens. However, the increased costs of more effective wastewater treatment are important limitations on the widespread use of advanced treatment [36]. In the current study, various techniques such as whole cells for removal, immobilisation-based methods, photobioreactor, Bio-CAST-based technology, pilot-scale biological nutrient removal technology, bio-electrochemical system (BES), membrane bioreactor (MBR), enhanced alure-type biological system (E-ATBS), hetero-photoautotrophic two-stage cultivation, microalgal biomass, sequential adaptation and deceleration-stat technique etc. and their efficiency observed by different scientists is discussed in detail below separately (Table 2). Advanced or tertiary wastewater treatment methods enhance removing the high concentrations of nutrients such as nitrogen and phosphorus in the water bodies that remain in the solution after the secondary treatment. However, improved methods are costly and require high maintenance. In contrast, natural treatment methods that employ natural physical, chemical, and biological processes may provide a more cost-effective means to treat wastewater [36,53,54].