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Introduction to Wastewater
Published in Sreedevi Upadhyayula, Amita Chaudhary, Advanced Materials and Technologies for Wastewater Treatment, 2021
Wastewater treatment is a process to remove contaminants from wastewater or sewage and convert it into effluent that can be returned to the water supply with an acceptable impact on the environment and can be reused for suitable purposes. Effluent can be defined as an outflow of treated water to the receiving water body. The contaminants from the collected water can be removed to a large extent by separation processes such as sedimentation, flotation, and filtration to produce high-quality water. Direct filtration of flocs can be used for raw water with low suspended solids. The primary objective of the treatment is to remove the particulate substances and dissolved inorganic and organic substances. These particulate substances must be removed by coagulation and flocculation using precipitation, coprecipitation, or adsorption. Phosphates, heavy metals, and dissolved organic substances of natural or anthropogenic origin are also removed by this treatment.3 See Table 1.2 for standards to be maintained for Common Effluent Treatment Plants by Government of India.
Bioprospecting Contaminated Soil for Degradation of the Drimaren X-BN Azo Dye
Published in Ederio Dino Bidoia, Renato Nallin Montagnolli, Biodegradation, Pollutants and Bioremediation Principles, 2021
Carolina Rosai Mendes, Guilherme Dilarri, Paulo Renato Matos Lopes, Ederio Dino Bidoia, Renato Nallin Montagnolli
The main treatments are degradation, filtration, flocculation, ozonation, precipitation, and adsorption. Some effluent treatments have disadvantages, such as excessive use of chemicals and high costs (Mendes et al. 2015). Biological treatment methods include microbial biodegradation under aerobic, anaerobic, anoxic, or anaerobic/aerobic conditions combined (Sarayu and Sandhya 2012). Biodegradation is an energy-dependent process and involves breaking the dyes through the action of various enzymes (Hameed and Ismail 2020). The complete breakdown of organic molecules with the production of water, carbon dioxide, or other inorganic products is called mineralization. The use of biological treatment consists of agitating the effluents in the presence of microorganisms and oxygen, for the time necessary to metabolize much of the organic matter. It is evident that biological effluent treatment processes have more advantages due to their low cost and complete mineralization of the dye molecule (Bouraie and Din 2016). One of the factors that accelerate the discoloration is the conditions of pure culture of strains that already have an enzymatic apparatus capable of degrading dye molecules. Maximum dye discoloration can be achieved by optimizing the conditions of pH, temperature, incubation time, dye concentration, and availability of suitable sources of carbon or nitrogen.
Literature Review
Published in Alberto Galvis Castaño, Integrated Pollution Prevention and Control for the Municipal Water Cycle in a River Basin Context, 2019
Besides pathogens, effluents also contain other pollutants that can be detrimental to the receiving water quality and to the environment at large. Once the need to eliminate water pollutants before discharging into rivers had been recognized, a great interest in the development of technologies for wastewater treatment (WWT) started. Technologies for primary treatment arose between 1860 and 1914. Between 1914 and 1965 technologies such as activated sludge, artificial wetlands and rotating biological reactors were developed. From 1965 onwards, new regulations for the protection of the environment emerged in many countries (Lofrano and Brown, 2010). In this period, the emphasis was on more widespread application of known techniques for Biological Oxygen Demand (BOD) and Total Suspended Solids (TSS) removal; environmental protection and improvement of removal of nitrate, phosphate and ammonia nitrogen; and disinfection (mainly in the USA). Figure 2.1 shows the most significant developments in the evolution of wastewater treatment.
The United Nations World Water Development Report 2022 on groundwater, a synthesis
Published in LHB, 2022
To prevent wastewater discharge and its negative impacts, the aim is to treat effluent to recover it as clean water and reuse it in the industrial process, reducing water consumption to near-zero levels. As such, water recycling to control water pollution is achieved in stages, first by making the effluent fit for treatment, through conventional physicochemical treatment, reverse osmosis and/or biological treatment. Thereafter, a series of post-treatment steps remove hardness, silt, turbidity and organics to a level where fouling of membranes does not occur. The Indian government has imposed this process on its textile and garment manufacturing industry by legislation, starting in 2006 in Tamil Nadu. Many factories were shut down by the state’s high court, due to their inability to meet compliance requirements. The policy has been expanded to nine states in the Ganges River basin and applied to five industrial sectors: textile, pulp and paper, distilleries, tanneries, and sugar. In recent research and development it has been replaced with the concept of “minimal” liquid discharge that enables up to 95% liquid discharge recovery. This takes into account that attaining the final 3–5% of liquid elimination can nearly double the treatment cost (80).
Plant pharmacology: Insights into in-planta kinetic and dynamic processes of xenobiotics
Published in Critical Reviews in Environmental Science and Technology, 2022
Tomer Malchi, Sara Eyal, Henryk Czosnek, Moshe Shenker, Benny Chefetz
Global water stress, a consequence of population growth, urbanization, higher living standards, and climate change, has increased the reliance of agriculture on treated wastewater as a vital source for irrigation worldwide (Hettiarachchi & Ardakanian, 2018; Yi et al., 2011). However, there are unknown potential environmental and human health consequences with the practice that must be considered (Fu et al., 2019; Vergine et al., 2017). In accordance with government regulations, treated effluent is discharged into the environment or reused for agricultural purposes (Hettiarachchi & Ardakanian, 2018). However, the ability of conventional treatment plants to remove pharmaceuticals is limited, resulting in their omnipresence in treated effluents (Evgenidou et al., 2015; Gracia-Lor et al., 2012; Kasprzyk-Hordern et al., 2009). Hence, the use of treated wastewater for irrigation exposes agricultural soil and crops to biologically active pharmaceuticals (Malchi et al., 2014; Paz et al., 2016). The accumulation of pharmaceuticals in edible crops introduces these compounds into the food chain and results in involuntary human exposure and subsequent unknown consequences (Paltiel et al., 2016; Schapira et al., 2020).
Critical review on lanthanum-based materials used for water purification through adsorption of inorganic contaminants
Published in Critical Reviews in Environmental Science and Technology, 2022
Koh Yuen Koh, Yi Yang, J. Paul Chen
As fresh water becomes less available due to the increase in demand and contamination, people have turned to the groundwater as one of the important water sources. However, the concentrations of arsenic and fluoride in the groundwater may be higher in some of the mineral-rich areas. Such contaminants would cause disasters to the people who rely on the well water as the source of drinking water in the areas. Consumption of high concentration of arsenic (e.g., > 10 ppb) can cause several cancers, while fluoride has negative impacts on the skeletal system of humans. The excessive release of phosphorus into the water streams can cause eutrophication, leading to the production of cyanobacteria and generation of toxins that are harmful to humans and cause damage to the ecosystem (Yang et al., 2008). Furthermore, such cationic heavy metals as copper, cadmium and lead are lethal and carcinogenic to humans. Therefore, government agencies and World Health Organization (WHO) have issued rules and regulations or guidelines on allowable limits for the trade effluent discharge and drinking water quality in order to safeguard the public health and the environment.