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Abstract Drinking water resources have always been limited in the gulf region of the Middle East and other desert regions around the world. In attempt to provide viable supplement, a device that harvests clean drinking water from air is designed, built and tested. The operation of the device is based on harvesting water naturally from air using adsorption materials. The prototype of this device consists of sorbent (silica gel is used in this study) exposed to radiant flux, water sorbent unit, condenser and reflector. Experimental studies of production of fresh water from air in controlled indoor environment have been carried out using the prototype. Several experimental tests were conducted under the conditions of 22 °C ambient temperature, a range of relative humidity (RH) from 30 to 60%, a range of silica gel thickness from 25 to 35 mm, surface area to volume ratio from 0.29 to 0.4 and radiant heat flux range from 509 to 556 W/m2. The prototype was able to produce up to 159 g of water per 1 kg of silica gel in a 12 h cycle when exposed to 556 W/m2 radiant flux. In terms of per one day (24 h), the harvester can produce 800 mL of water with an overall efficiency of 50% for 25 mm silica layer thickness. Increasing the relative humidity speeds up the adsorption cycle and increases the water capture, release and collection rates. The system can be improved by adding multiple layers of sorbent stacked on top of each other and by using sorbents with improved adsorption and desorption properties.

Abstract Climate change will lead to higher temperatures, increased precipitation and runoff, as well as more intense and frequent extreme weather events in Norway. More extreme rainfall and increased runoff are historically associated with higher concentrations of indicator bacteria, colour and turbidity in raw water of Norwegian waterworks. Regional information about the risk for drinking water deterioration by the end of the century is essential for evaluating potential treatment capacity upgrades at the waterworks. We combined locally downscaled future climate scenarios with historical associations between weather/runoff and water quality from a wide spread of waterworks in Norway. With continued climate change, we estimate higher concentrations of water quality indicators of raw water by the end of the century. The water quality is estimated to deteriorate mainly due to the projected increase in rainfall, and mainly in the Western and Northern parts of Norway. While large waterworks seem to be able to adapt to future conditions, the degradation of raw water quality may cause future challenges for the treatment processes at smaller waterworks. Combining these results with further studies of treatment effects and microbial risk assessments is needed to ensure sufficient treatment capacities of the raw water in the future.

We appreciate Ford’s documentation of the many ways in which climate change threatens the traditional lifestyles and health of indigenous and other populations.1 As Ford states, the impacts of climate change on indigenous peoples are primarily studied in Australia and the Arctic, leaving much unknown about their global scale and manifestations in other regions.1 We believe that small island communities such as the Caribbean are also vulnerable to climate change because of their coastal-dependent geographies and lifestyles. The Caribbean population was estimated at 37.5 million in 2000,2 and Caribbean nations constitute approximately half of the 39 members of the Association of Small Island States.3 Like much of the world,4 the Caribbean is already experiencing increased salinity of drinking water, sea level rise, decreased habitable and agricultural land area, disrupted fisheries, and diminished food security.5 Its limited infrastructure and socioeconomic resources leave it at least partly reliant on foreign aid for climate mitigation and preparedness efforts. In one of our qualitative studies, Caribbean islanders described their personal experiences and perceptions about climate change as increased average temperatures, severity of weather events, and changes in rainfall patterns. They had observed geographic changes including beach erosion, sea level rise, drying rivers, and reduced vegetation and ground cover. They discussed the growing regional attention to disaster preparedness since the devastation of Hurricane Ivan in 2004, including efforts to digitize and archive legal and historical documents to prevent losses like those caused by Hurricane Ivan. Participants identified subsequent regional business opportunities in conservation and alternative energy, government efforts to promote the use of drought resistant crops after the severe drought of 2010, and a policy on climate change education being considered for public schools. Participants noted that relatively high rates of interisland movement and population growth stretch Caribbean social services and encroach on diminishing areas of habitable land. The discussion itself seemed to galvanize participant recognition that climate change threatens natural resources, such as rushing rivers and sandy beaches, that they take for granted. Although preliminary, our data show that climate change is altering Caribbean life. Further research on the health impacts of climate change on indigenous peoples and in unique geographic, economic, and sociocultural contexts is needed. Governments, industries, and individuals are unlikely to respond to climate change until it threatens things they value in their own lives. Ford’s article, and findings like ours, may help them to appreciate the urgency of doing so.

High nutrient discharge from groundwater (GW) into surface water (SW) have multiple undesirable effects on river water quality. With the aim to estimate the impact of anthropic pressures and river–aquifer interactions on nitrate status in SW, this study integrates two hydrological simulation and water quality models. PATRICAL models SW–GW interactions and RREA models streamflow changes due to human activity. The models were applied to the Júcar River Basin District (RBD), where 33% of the aquifers have a concentration above 50 mg NO3−/L. As a result, there is a direct linear correlation between the nitrate concentration in rivers and aquifers (Júcar r2 = 0.9, and Turia r2 = 0.8), since in these Mediterranean basins, the main amount of river flows comes from groundwater discharge. The concentration of nitrates in rivers and GW tends to increase downstream of the district, where artificial surfaces and agriculture are concentrated. The total NO3− load to Júcar RBD rivers was estimated at 10,202 tN/year (239 kg/km2/year), from which 99% is generated by diffuse pollution, and 3378 tN/year (79 kg/km2/year) is discharged into the Mediterranean Sea. Changes in nitrate concentration in the RBD rivers are strongly related to the source of irrigation water, river–aquifer interactions, and flow regulation. The models used in this paper allow the identification of pollution sources, the forecasting of nitrate concentration in surface and groundwater, and the evaluation of the efficiency of measures to prevent water degradation, among other applications.

The greenhouse gas (GHG) emissions, expressed in carbon dioxide equivalents (CO2-eq), of different Austrian biogas systems were analyzed and evaluated using life-cycle assessment (LCA) as part of a national project. Six commercial biogas plants were investigated and the analysis included the complete process chain: viz., the production and collection of substrates, the fermentation of the substrates in the biogas plant, the upgrading of biogas to biomethane (if applicable) and the use of the biogas or biomethane for heat and electricity or as transportation fuel. Furthermore, the LCA included the GHG emissions of construction, operation and dismantling of the major components involved in the process chain, as well as the use of by-products (e.g. fermentation residues used as fertilizers). All of the biogas systems reduced GHG emissions (in CO2-eq) compared with fossil reference systems. The potential for GHG reduction of the individual biogas systems varied between 60% and 100%. Type of feedstock and its reference use, agricultural practices, coverage of storage tanks for fermentation residues, methane leakage at the combined heat and power plant unit and the proportion of energy used as heat were identified as key factors influencing the GHG emissions of anaerobic digestion processes.

Abstract In this study, intergeneric grafting was employed between Populus cathayana and Salix rehderiana to investigate the grafting compatibility of the two Salicaceae plants and to reveal whether grafting can improve their drought resistance. Under different grafting combinations (P. cathayana scion with P. cathayana rootstock, P/P; P. cathayana scion with S. rehderiana rootstock, P/S; S. rehderiana scion with S. rehderiana rootstock, S/S; and S. rehderiana scion with P. cathayana rootstock, S/P), the survival and growth rate, biomass accumulation and allocation, photosynthetic traits, carbon isotope composition (δ13C), relative water content (RWC) and non-structural carbohydrates (NSCs) were measured. The results showed that the grafting compatibility between P. cathayana and S. rehderiana was very high, as the survival rates ranged from 76% to 100% under different grafting combinations. Drought significantly decreased growth, biomass accumulation, photosynthetic pigment contents, net photosynthesis rates (Pn) and RWC, and increased δ13C in all grafting combinations. Under drought stress, biomass accumulation, total chlorophyll, transpiration rate (E) and Pn were higher in P/P and P/S than in S/S and S/P. Compared with P/P, the growth rate, biomass accumulation, root/aboveground ratio (R/A ratio), carotenoid, RWC, starch and total soluble sugar (TSS) of P/S were less affected by drought. The height growth rate (GRH), R/A ratio, carotenoid, chlorophyll a, total chlorophyll, WUEi and TSS of S/P were lower than those of S/S under water-limited conditions. Moreover, a principal component analysis indicated that P/S and S/S had higher drought resistance than P/P and S/P under water deficits. The used method allows combining specific advantageous traits from P. cathayana and S. rehderiana, which may be a highly useful tool to enhance drought resistance in the cultivation of Salicaceae plants.

The aim of this study was to examine the risk of heavy metal, ammonia and sulfate transition from underground coal gasification (UCG) chars and process water of Malkara lignite to the groundwater around the UCG cavity. The residues were collected during laboratory-scale underground coal gasification studies of Malkara lignite in ex situ gasification simulator. In order to compare gasification with combustion in terms of water pollution, ash samples were obtained by combustion of Malkara lignite. To determine the leaching behavior of the char and ash samples, two leaching tests (EPA TCLP and EN 12457-2 methods) were applied. The concentration of heavy metals in char, ash and process water samples was determined by ICP-OES. Additionally, ammonia and sulfate analyses were conducted for process water. Based on the results of this study, it has been found that the concentration of some elements, such as B, Sb and Al in char and ash eluates exceeded the maximum level of drinking water standards. However, there is no landfill concern about char samples according to EU Landfill Directive. A significant increase in B concentration was observed in ash samples. Considering B and some other elements combustion residues were identified with much higher water contamination ability, compared to gasification residues. Ammonia concentration was observed extremely high in process water of the gasification tests. UCG technique may be more environmentally applicable technology compared to combustion for Malkara lignite reserves. However, further detailed studies are necessary in the early stage of the UCG field test design and application.