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).
Inequity in access to water
Théodore H MacDonald in Removing the Barriers to Global Health Equity, 2018
In 2006, Bechtel’s total revenue amounted to $20.5 billion and Interagua’s operations in Guayaquil earned $300 million in revenue. Despite these profits, Interagua did not initiate the rehabilitation programs it had promised. Concerns and complaints mounted over broken pipelines, floods due to malfunctioning sewage systems, exorbitant water rates, poor water quality, and environmental damage due to the lack of wastewater treatment during this first five-year period. Lack of investment in storm drainage forced many residents to suffer the health effects of constant flooding. In 2002 the company was treating only 5% of the sewage and releasing the rest, including fecal material, and domestic and industrial waste directly into the local river, Guayas. The health department began to issue reports documenting health problems that children were experiencing in communities located north of the city, such as Acuarelas del Río and Guayacanes, where the sewage was being released. The health problems included skin rashes, asthma, and gastric problems such as diarrhoea.
Avoiding Risky Substances and Environmental Exposures
Michelle Tollefson, Nancy Eriksen, Neha Pathak in Improving Women's Health Across the Lifespan, 2021
Clean water is essential for life; however, challenges in water infrastructure and wastewater management, along with population growth changes, can threaten access to and quality of drinking water.37 Key water quality contaminants include lead, mercury, and emerging substances including per- and poly-fluoroalkyl substances (PFAS). Lead is a neurotoxic metal that poses a great long-term threat to fetuses, infants, and children. In addition to contaminated water, exposure sources include soil and dust along with lead-based paints and manufacturing. Mercury is a toxic substance formed naturally in the environment as well as anthropogenically. It can be released from the burning of fossil fuels, can be mined from the earth, is used in thermometers, and is used medicinally in dental restorative amalgam (silver) fillings. In the environment, mercury can settle into water or soil. It is a persistent pollutant and can bioaccumulate in fish (methylmercury) and biomagnifies up the food chain.38 Populations, therefore, are exposed through water that contaminates food, as well as air and soil.38 PFAS are a class of widespread persistent contaminants, often called “forever chemicals” due to their lengthy half-life in the environment. People can be exposed through contaminated drinking water (predominant exposure source) as well as through occupational exposures. The presence of PFAS in our environments can be quite ubiquitous due to its presence in industry, in waste infrastructure, and in consumer products, including use as a flame retardant, marking its presence in textiles, firefighting foam, airplanes, anti-stick cookware, and food packaging. PFAS is a blood contaminant, a possible carcinogen, an immunotoxin, a metabolic toxin, and a potential endocrine disruptor.39
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.
Removal efficiency of PAH’s from five wastewater treatment plants in Jordan
Published in Toxin Reviews, 2018
Mahmoud A. Alawi, Ibrahim N. Tarawneh, Zahra’ Ghanem
Wastewater is a combination of the water and carried waste removed from residential, institutional and commercial establishments together with infiltration of water, surface water and runoff water (Al-khashman et al., 2013). Wastewater contains various persistent organic pollutants (POP’s), these organic pollutants enter the wastewater by direct or indirect release from household and industry or by atmospheric deposition on surface and then runoff into the wastewater treatment system (Guo et al., 2009). On the other hand, wastewater is a valuable source of nutrients and organic matter, so the high amount of sludge produced by wastewater treatment plants (WWTP’s) could be considered as an economical way to get fertilizer to agricultural land, but if it has a high concentration of POP’s (due to their lipophilic nature which make them preferentially partition onto sludge during wastewater treatment process), this may have a negative impact on soil organisms and fertility (Guo et al., 2009).
Related Knowledge Centers
- Activated Carbon
- Biogas
- Sewage
- Ultrafiltration
- Water Cycle
- Reclaimed Water
- Sewage Treatment
- Industrial Wastewater Treatment
- NON-Aqueous Phase Liquid
- Redox