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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
Before water can be used for human consumption, biological and chemical contaminants need to be removed from the raw water in water treatment plants. Raw water usually contains microorganisms, pathogens, and a variety of non-desirable or excessive organic and inorganic chemicals and compounds containing arsenic, chromium, copper, and lead as well as various micropollutants and emerging contaminants. To remove (or transform) these contaminants, a typical or conventional municipal water treatment plant involves a series of physical and chemical processes as shown in Figure 25.1. The different steps described here correspond to the processes used in the main drinking water treatment plant in Geneva (Switzerland), providing drinking water for 500,000 consumers. The number and nature of these water treatment processes have to be adjusted and calibrated to raw water physico-chemical properties and desired drinking water quality and quantities. Financial considerations must also be considered since they contribute to determining what is feasible or not. Here the water treatment process is a conventional one and involves a multistage procedure, including raw water pre-treatment, acidification, flocculation, sand filtration, ozonation, activated carbon filtration, pH neutralization, and final disinfection.
Group Model Building on Qualitative WEF Security Nexus Dynamics
Published in Aries Purwanto, Grasping the water, energy, and food security nexus in the local context, 2021
The developed water sector sub-model is shown in Figure 4.4. The source of raw water in this region comes from surface water (rivers, lakes and ponds) and underground water. Imported water as the main water source is interpreted as water supply from Jatiluhur Reservoir whose location is administratively located outside Karawang Regency. On the other hand, water demand comes from agricultural, domestic and industrial activities. The supply and demand of water affect water availability in this area. Problems related to water availability arise in this region during the rainy and dry season. The lack of water storage in the area leads to flooding in some areas during the rainy season. Conversely in the dry season, the crop failure frequently occurs also due to the lack of reliable water supply. In addition to the availability factors, water accessibility and particularly water quality were discussed intensively in the model preparation. This is due to the fact that this regency is not only an agricultural area but also an industrial area with potential pollution to the rivers and other water sources (Figure 4.4), which could impact negatively on agricultural production. Artificial ponds development is focusing on the green space in individual housing, industrial and rain fed agricultural areas in this region. Thus, the enlargement of those sectors’ developments is expected to increase the number of artificial ponds. In the end, it could enhance local water production and conversely reduce the imported water demand.
Microfiltration Membranes: Fabrication and Application
Published in Sundergopal Sridhar, Membrane Technology, 2018
Barun Kumar Nandi, Mehabub Rahaman, Randeep Singh, Mihir Kumar Purkait
Clean drinking water is a basic need of every species on earth. Therefore, mankind is always in search of clean water sources or processes that make the available raw water clean and safe for consumption. Membrane processes have become very popular due to their effective capability to remove a variety of impurities from raw water. MF and UF membranes have capabilities to remove suspended particles. On the other hand, nanofiltration (NF) membranes are effective for the removal of dissolved organic contaminants with molecular weights more than 200 Da. The mechanisms involved during removal of contaminants from raw water are electrostatic repulsion, size exclusion and a combination of other factors including preferential affinity. MF is a favorable choice for pretreatment due to its ability to remove contaminants and without addition of chemicals. Also, the availability of ceramic microfiltration membranes makes them more popular due to their low susceptibility to fouling and durability. Other pretreatment processes such as coagulation–flocculation fail to remove the broad spectrum of contaminants present in raw water. The commonly present contaminants in the raw water are macromolecular and dissolved or sparingly soluble organic substances, soluble inorganic compounds, colloidal and particulate matter like silica and microorganisms. The time-tested MF membrane provides a platform for the perfect pretreatment process. Thereafter, NF or RO could be applied to get clean drinking water making the whole process economical, swift and smooth.
Fabrication of spirulina based activated carbons for wastewater treatment
Published in Environmental Technology, 2022
Mustafa Rakib, Yeshaswini Baddam, Balakrishnan Subeshan, Ayse B. Sengul, Eylem Asmatulu
Water treatment is a process that provides high-quality water for human consumption purposes, used to remove different contaminants such as suspended solids, nitrogen, pesticides, toxic metals, bacteria, and viruses from raw water. Currently, various physical, chemical, or biological processes are used to remove such contaminants from water, including coagulation/flocculation, sedimentation, filtration, oxidation, adsorption, disinfection, and membrane filtration [2–4]. Traditional water treatment methods, including sedimentation, flocculation, coagulation, and filtration generally aim to eliminate suspended and colloidal particles. Other treatment processes such as adsorption, chlorination, oxidation, and membrane filtration aim to remove dissolved organic and inorganic compounds. Among all treatment processes, the adsorption process can effectively remove tastes, odours, synthetic organic compounds, disinfection by-products, and inorganic chemicals [5,6]. In adsorption processes, activated carbon is commonly applied as an adsorbent because of its extremely high porosity, high adsorptive capacity, and high surface area [7–16]. By using carbonaceous materials such as wood, coal, rice husks, coconut shells, and agricultural materials, it is possible to construct it by carbonisation and chemical or physical–chemical activation [17–24].
Parameters affecting enhanced coagulation: a review
Published in Environmental Technology Reviews, 2018
Kanika Saxena, Urmila Brighu, Aditya Choudhary
In the baseline coagulation, the conditions are optimised for turbidity removal whereas the optimised coagulation refers to the dose and pH conditions optimised especially for organic matter reduction. Enhanced coagulation refers to the addition of excess coagulant than baseline coagulation, with changes in pH, the order of chemical addition or use of alternative coagulant chemicals, for more efficient NOM removal. In enhanced coagulation, the process is optimised for NOM removal, unlike turbidity removal which is the case for baseline coagulation [3–5]. Organic contaminants such as endocrine disrupting compounds, personal care products, pharmaceutical products, etc. are also present in very minimal quantities in the raw water known as trace organic contaminants. However, coagulation and flocculation is found to be ineffective for removing trace organic contaminants, although for bulk NOM which is a greater portion of NOM other than the trace organic contaminants, the removal is found to be very efficient [6].
A cyber-physical system architecture based on lean principles for managing industry 4.0 setups
Published in International Journal of Computer Integrated Manufacturing, 2022
Amr Nounou, Hadi Jaber, Ridvan Aydin
Raw water is first treated for the processes of coagulation, filtration, and disinfection to obtain the required odour, taste, and colour. Then, the water is carried into the water bottling and water gallons departments via pipes for filling, capping, and packaging processes. Preformed plastics are readily procured from two suppliers from Turkey and Italy. After they are fed and heated, hot air is blown inside to produce the required bottles and gallons. Then, the water carried from the water treatment department is filled into bottles and gallons. After that, the bottles/gallons are capped, labelled, and packaged based on customer demand. Finally, packaged bottles/gallons are handled and carried into the warehouse before shipping to the customers.