Wastewater treatment *
Jamie Bartram, Rachel Baum, Peter A. Coclanis, David M. Gute, David Kay, Stéphanie McFadyen, Katherine Pond, William Robertson, Michael J. Rouse in Routledge Handbook of Water and Health, 2015
Wastewater treatment, or the process of enhancing wastewater quality, is critical to protecting ecosystems and public health from physical, microbial, chemical and high nutrient pollution. Wastewater treatment is nearly universal in developed countries, but around 90 percent of all wastewater in developing countries is discharged without treatment to rivers, lakes and oceans (UNEP 2010). Many people do not have access to any form of sanitation, such that, globally, 4.1 billion people lack access to improved sanitation, defined as sanitation including water treatment (Baum et al. 2013), and, depending on the enforcement of environmental standards, much of the wastewater produced by industry remains untreated in developing nations (Johnstone 2003). In densely populated South and Southeast Asia, only 30 percent of cities from one survey have wastewater treatment systems, but treatment remains a low government priority, with only 40 percent of cities reporting having a sanitation plan (Asian Development Bank 2009). This chapter describes domestic and commercial wastewater treatment. We direct the reader elsewhere for more background on processes to remove specific pollutants from specific industries (Wheeler and Pargal 1999; Johnstone 2003; International Finance Corporation 2007; Salmoaa and Watkins 2011).
Wastewater Phycoremediation by Microalgae for Sustainable Bioproduct Production
Gokare A. Ravishankar, Ranga Rao Ambati in Handbook of Algal Technologies and Phytochemicals, 2019
In a wastewater treatment system, the elimination or reduction of unnecessary contaminants such as biochemical oxygen demand (BOD), toxins, bacteria, suspended solids, nutrients and coliform is necessary and must therefore comply with international standards. Wastewater treatment consists of physical, chemical and biological processes. The process applied in conventional wastewater treatments is summarized in Figure 1.1.
Optimization of an integrated system for refinery wastewater treatment
Published in Toxin Reviews, 2020
Ali Almasi, Leila Yavari, Mitra Mohammadi, Seyyed Alireza Mousavi
The oil industry is one of the industries that produce wastewater with high potential pollutants. The refinery wastewater due to high toxicity and resistance to biological degradation can cause serious damage to the ecosystem (Almasi et al. 2016). These wastewaters consist of high concentrations of aromatic and aliphatic hydrocarbons that conventional biological treatment methods are unable to treat. Therefore, researchers have applied advanced oxidation process as promising methods for removing and increasing biodegradability of resistance wastewaters (Mosavi et al. 2016, Yu et al. 2017). Wastewater treatment of oil refineries have been carried out using various methods including physical operation (dissolved air flotation, adsorption, and membrane filtration), chemical (chemical oxidation, electrochemical, coagulation, electrocoagulation, and Fenton), and biological process. However, physical operation and chemical process are costly due to the high cost of chemicals and equipment and the need to remove excess sludge while, the biological processes are preferred for simplicity, affordability, and environmental compatibility. Biological processes are an economical option for conventional wastewater treatment. But these processes cannot always provide satisfactory results for industrial wastewater treatment alone. Therefore, it should be used in integration with physical or chemical processes. Nowadays, the combination of chemical and biological treatment processes is recommended as an economical method for treatment of wastewater containing resistant compounds (Guieysse and Norvill 2014).
Enhanced removal of antibiotics using Eichhornia crassipes root biomass in an aerobic hollow-fiber membrane bioreactor
Published in Biofouling, 2022
Sevcan Aydin, Duygu Nur Arabacı, Aiyoub Shahi, Hadi Fakhri, Suleyman Ovez
Developing novel technologies for wastewater treatment that are both environmentally friendly and economically feasible has become a pressing need and gathered much attention from researchers (Aydin et al. 2022). Membrane bioreactors (MBRs) are a novel wastewater treatment technology that combine membranes with activated sludge. MBRs have garnered attention in the recent years due to their advantages over conventional treatment systems, such as a lower carbon footprint, lower costs and higher quality effluents (Judd 2008; Hai and Yamamoto 2011; Yu et al. 2014). MBRs have been repeatedly reported to efficiently remove antibiotics. For instance, Park et al. (2017) reported 52% removal efficiency for tetracycline using HF-MBR. However, MBRs still have challenges to be faced before widespread implementation, such as biofouling of the membrane. Biofouling is the unwanted accumulation of microorganisms and small particles on the surface of the membrane, and the subsequent growth of these microorganisms, thus leading to a decreased filtration area. However, cleaning and replacement of membranes are costly (Hamedi et al. 2019). Thus, prevention and alleviation of membrane biofouling is an important subject that requires further research.
Hybrid powdered activated carbon-activated sludge biofilm formation to mitigate biofouling in dynamic membrane bioreactor for wastewater treatment
Published in Biofouling, 2022
Mohammad Reza Mehrnia, Fatemeh Nasiri, Fatemeh Pourasgharian Roudsari, Fatemeh Bahrami
Global insufficiency of water resources besides the widespread pollution of existing water bodies has put the process of wastewater treatment and reuse among the most substantial issues in the environmental engineering area. As a modern paradigm shift, wastewater is now considered a renewable resource which is capable of producing clean water, useful nutrients and renewable energy (Aslam et al. 2022). Different wastewater treatment approaches have been proposed, including physical (Prathapar et al. 2006) and chemical (Pidou et al. 2008) techniques, advanced oxidation process (AOP) (Liu et al. 2021) and biological methods (Holloway et al. 2021). Among them, biological methods, independently or in combination with other techniques (Xiang et al. 2021), stand out because of being cost efficient and lack production of more dangerous intermediates (Ayed et al. 2017). Moreover, the hybrid techniques can overcome the drawback of independent biological treatment, which is the removal of specific toxic compounds.
Related Knowledge Centers
- Activated Carbon
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- NON-Aqueous Phase Liquid
- Redox