During the COVID-19 pandemic, high consumption of antivirals, antibiotics, antiparasitics, antiprotozoals, and glucocorticoids used in the treatment of this virus has been reported. Conventional treatment systems fail to efficiently remove these contaminants from water, becoming an emerging concern from the environmental field. Therefore, the objective of the present work is to address the current state of the literature on the presence and removal processes of these drugs from water bodies. It was found that the concentration of most of the drugs used in the treatment of COVID-19 increased during the pandemic in water bodies. Before the pandemic, Azithromycin concentrations in surface waters were reported to be in the order of 4.3 ng L −1 , and during the pandemic, they increased up to 935 ng L −1 . Laboratory scale studies conclude that adsorption and advanced oxidation processes (AOPs) can be effective in the removal of these drugs. Up to more than 80% removal of Azithromycin, Chloroquine, Ivermectin, and Dexamethasone in aqueous solutions have been reported using these processes. Pilot-scale tests achieved 100% removal of Azithromycin from hospital wastewater by adsorption with powdered activated carbon. At full scale, treatment plants supplemented with ozonation and artificial wetlands removed all Favipiravir and Azithromycin, respectively. It should be noted that hybrid technologies can improve removal rates, process kinetics, and treatment cost. Consequently, the development of new materials that can act synergistically in technically and economically sustainable treatments is required.

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Carbonate scale is one of the main problems in hot water systems, and therefore, interest in this subject has grown since 2000s. Water treatments, based on magnetic and electromagnetic (EM) techniques to prevent scale, are being commercialized, but their effectiveness is not clearly demonstrated because it depends on temperature, pressure, dissolved CO2, pH, field intensity, water flow, etc. In this paper, a review of these techniques, together with other classical techniques, such as chemical softening, the use of inhibitors, ion exchange, electrochemical and membrane treatments is presented. The latter alter the composition of the water and generate hazardous waste for health and the environment, unlike magnetic and EM treatments, which are considered non-invasive techniques. Different hypotheses are used to explain the effect of these treatments, such as the formation of aragonite instead of calcite or crystal nuclei formation within the fluid. Analysis of salts formed with SEM, X-ray diffraction, or colorimetric tests seem to support the efficiency of these treatments since study in the fluid is not easy. Dissolution of the formed scale or its prevention endorse the commercialization of these techniques, but their effectiveness must be verified in each installation.

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a b s t r a c tThe aim of this paper is to evaluate the importance of seawater desalination to the supply of fresh water to SE Spain in order to tackle the problem of the shortage of water resources. The Mancomunidad de los Canales del Taibilla (MCT) supplies water to a population of more than 2,400,000 inhabitants in SE Spain. Resources managed by the MCT include the Taibilla river basin, water from the Tajo-Segura transfer, other unusual occasional groundwater contributions and from 2003, sea water desalination. Four desalination plants: Alicante I and II and San Pedro del Pinatar I and II together with resources from other desalination plants provide a significant amount of resources. For a decade (2004-2013) the resources coming from sea water desalination averaged 20.2% of all the resources used by MCT, with 427 Mm 3 of total production in the period studied. However, the yearly contribution of desalination has changed depending on the availability of other resources. Moreover, seawater desalination has been essential to ensure water supply in the Alicante and Murcia areas. This resource has been important in periods of shortage, but also in unusual exploitation situations, such as that of the post-transfer tunnel detachment, which was classified as the most important breakdown of this infrastructure within its long lifetime. Moreover, scenarios of future climate changes could increase demands for water supply.