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Geotechnical aspects of groundwater recharge in arid regions
Published in H. Rahardjo, D.G. Toll, E.C. Leong, Unsaturated Soils for Asia, 2020
Reclaimed water is normally considered for non-potable water use such as landscape irrigation. However, municipalities and other government agencies express interest in use of reclaimed water as an indirect potable water supply. Recharge of groundwater supplies with treated waste effluent together with the use of soil aquifer treatment (SAT) to improve water quality represents one method for maintaining adequate water supplies in arid regions. Studies to date show that SAT is a feasible treatment process and that treated wastewater represents a viable source for replenishment of groundwater supplies.
Wastewater treatment and groundwater recharge for reuse in agriculture: Dan Region reclamation project, Shafdan
Published in Jos H. Peters, Artificial Recharge of Groundwater, 2020
SAT serves to improve the effluent quality to near-drinking-water level, through treatment in both the unsaturated and the saturated zones. Residence time between infiltration and recovery is ~100–300 days. Treatment includes physical processes of filtration, occurring in the top layer of soil; physiochemical processes such as adsorption, ion exchange and precipitation, occurring throughout the soil profile; and biological processes such as breakdown of carbonaceous organic matter and full nitrification and partial denitrification, which occur throughout the unsaturated and saturated zones (Kanarek and Michail, 1994). Filtration accounts for the removal of much of the particulate material and turbidity, and to a certain extent removal of microorganisms (natural dieoff accounts for additional microbial improvement). Chemical processes are responsible for removal of phosphorus and some trace elements (Cr, Cd, Cu, Mo, Ni and Se), while biological processes improve COD/BOD removal, and are responsible for complete nitrification and partial dentirification. In all, quality of the reclaimed water is suitable for unrestricted agricultural use (including vegetables to be eaten raw) , industrial uses, and non-potable municipal use (such as lawn irrigation). At present, however, the water is used only for agriculture. Table 2 presents the quality of reclaimed water in a representative observation well, following recharge of activated sludge plant effluents.
Reclaimed Wastewater Quality Criteria, Standards, and Guidelines
Published in Donald R. Rowe, Isam Mohammed Abdel-Magid, Handbook of Wastewater Reclamation and Reuse, 2020
Donald R. Rowe, Isam Mohammed Abdel-Magid
Usually, the criteria, standards, or guidelines that are required for this class of reuse are more stringent than those required for non-body contact sports. Reclaimed wastewater requirements include: Reclaimed water needs to be aesthetically attractive.The water used must have an acceptable physical quality; this is to be established through the control of parameters such as color, taste, odor, temperature, solids concentration, and turbidity.Reclaimed water must be free of toxic compounds and other harmful chemical substances. For example, the reclaimed water must have an acceptable pH level. The pH can range from 6.5 to 8.3. The lacrimal fluid of the human eye has a pH of around 7. The deviation of the pH of the reclaimed water from the normal value may result in irritation to the eyes.The reclaimed water must be hygenically safe and free from disease-causing agents.
Systems thinking for the sustainability transformation of urban water systems
Published in Critical Reviews in Environmental Science and Technology, 2023
Wan Izar Haizan Wan Rosely, Nikolaos Voulvoulis
Despite the differences in their names and origins, most of these initiatives are based on systems thinking and to different degrees follow systemic principles. For example, in addressing increasing water demand, UWDM prioritizes systemic actions to reduce or modify water consumption and abstraction of water as well as protection of water resources from pollution, over the development of large and capital-intensive water infrastructure. It involves improving urban water systems efficiency (e.g.: reducing water leakage through active leak detection or network replacements and reducing water usage through meter installations), and diversification of water sources (rainwater harvesting, greywater reuse, source separation, or on-site treatment). For instance, several cities in the US and Australia have built reclaimed water networks to supply households with water for non-potable use, reducing the need for abstracting water (Hess & Collins, 2019; Mainali et al., 2014). In other cases, emphasis has been placed on the dissemination of cost information for providing water and treating wastewater to the public, and on improving their awareness of the value of water, enhancing their willingness to pay more for these services (Arfanuzzaman & Rahman, 2017; Sharma & Vairavamoorthy, 2009).
Conjunctive use of groundwater and surface water to reduce soil salinization in the Yinchuan Plain, North-West China
Published in International Journal of Water Resources Development, 2018
Peiyue Li, Hui Qian, Jianhua Wu
Lowering the groundwater can also be achieved by reducing groundwater recharge and increasing water-use efficiency in the plain. According to the calculated water budget, leakage from irrigation canals and infiltration from irrigation water are the two largest sources of groundwater recharge (Qian et al. 2012). Therefore, it is mandatory to carry out canal maintenance to avoid canal leakage and increase the water-use efficiency of canals. Advanced irrigation methods are also necessary, such as drip or sprinkler irrigation, to reduce the amount of irrigation infiltration. Avoiding flood irrigation as much as possible is recommended. More importantly, crop layout must be planned scientifically to reduce the water needed for irrigation. Rice is the most common crop in the plain, but it requires a large amount of water for irrigation and demands perfect drainage systems. It is therefore highly recommended that decision makers encourage farmers to rotate planting of rice and maize, which would help alleviate the salinization problem in the plain. Crops should also be irrigated according to their needs at different stages of their growth. In some local areas, reclaimed water should be used to supplement irrigation water. This will help reduce the amount of water diverted from the Yellow River, increasing water-use efficiency and reducing the burden of drainage. For example, in the Huinong District of Shizuishan, there are large amounts of reclaimed water available in the drainage ditches. The quality of the reclaimed water is generally suitable for irrigation.
Fit-for-purpose urban wastewater reuse: Analysis of issues and available technologies for sustainable multiple barrier approaches
Published in Critical Reviews in Environmental Science and Technology, 2021
Water reuse, regardless of specific application, has generally recognized positive benefits that may include reduced process and transport energy consumption, reduced treatment and distribution costs, environmental boons, such as lower nutrient loads to receiving waters, nutrient recycle and improved crop production, and reduced GHGs emission. To date, hundreds of projects have been already implemented worldwide for different end uses, cumulatively demonstrating that adequately treated reclaimed water is safe for human health and the environment.