Water Shortage Issues Research Articles

Delineation of suitable sites for groundwater dams in the semi-arid environment in the northeast of Iran using GIS-based decision-making method

Competing commercial demands on water resources need to be balanced as the world's population rises. Generally, groundwater is raised by subsurface dams. In this paper, the geographic information system (GIS) software and a decision-making method were applied. As the first step, the limitations that affect the establishment of the subsurface dam were identified using eliminating criteria by the Boolean logic. Regarding the second step, the most appropriate axis was determined for subsurface dam construction in each of the limits. The analytical hierarchy process (AHP) was applied according to the evaluation criteria in this study. The aim of using AHP was to weigh and prioritize the criteria of the groundwater dam for recognizing appropriate sites. Among various places and regarding the subsurface dam construction, AHP was conducted using a hierarchy process for finding the most suitable sites in the third stage of the decision-making method. Finally, among the ten appropriate sites, cross comparison was drawn by using Decision Expert (DEX), Evaluation based on Distance from Average Solution (EDAS), and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). Compared together (as a process of decision-making), DEX, TOPSIS, and EDAS methods assisted in ranking the most appropriate sites in the final step of subsurface dam pre-selection. A and C axes obtained scores between 1 and 2, among 10 axes according to the numerically ranked locations. Regarding the water shortage issue and better management of the underground water at certain levels, the findings of this study could be useful for the residents of Kajbid-Balaqly Watershed in the dry season. Further, water managers can use the above-mentioned methods for their decisions regarding the proper subsurface dam establishment.

Dual-Functional Graphene Oxide-Based Photothermal Materials with Aligned Channels and Oleophobicity for Efficient Solar Steam Generation.

Desalination by solar steam generation (SSG) has emerged as one of the most efficient approaches to address the issue of global water shortage. In this work, novel graphene oxide (GO)-based solar steam generators (GO-SSGs) with aligned channels were prepared by directional freezing and simple carbonization of a hydrogel composed of GO and poly(vinyl alcohol) (PVA). Benefitting from their excellent light absorption (light absorption efficiency exceeds 94%), better thermal insulation (thermal conductivity, 0.259 W/(m K)), and suitable porous structure, which facilitates rapid water transportation, the GO-SSGs show superior SSG performance with a high solar energy conversion efficiency of up to 92% achieved under an irradiation of 1.0 kW/m2. Interestingly, uniquely aligned channels endow them with good salt-rejection performance; the solar energy conversion efficiency of GO-SSGs in 20 wt % NaCl, KCl, and MgCl2 brine can reach more than 85%. To improve their antifouling performance, a chemically hydrophilic and oleophobic modification was conducted, making it possible to run SSG even in oily wastewater; for instance, a solar energy conversion efficiency of 84% was obtained in an aqueous solution containing 10 wt % n-hexadecane. Compared with the existing photothermal materials, these materials show advantages of simple manufacture, high SSG efficiency, superior salt tolerance, and antifouling performance, which make them promising candidates as a kind of new high-performance photothermal materials for desalination even in oily wastewater, thus further expanding the scope of their practical SSG application.

Multi-Synergistic Removal of Low-Boiling-Point Contaminants with Efficient Carbon Aerogel-Based Solar Purifier.

Solar steam generation is considered as an efficient way for addressing water shortage issues via seawater desalination and wastewater purification. In a solar evaporator, an absorber would convert optical energy to heat for evaporating nearby water. In this process, many low-boiling-point contaminants can also be evaporated along with water steam, which compromises the effectiveness of purification. There is, so far, no study on the removal of such low-boiling-point contaminants such as organic pesticides in wastewater. To address this problem, we demonstrate a versatile carbon hybrid aerogel (CHA) as a solar powered water purification platform. With an elaborate absorber design, the maximum solar evaporation rate of 2.1 kg m-2 h-1 is achieved under 1 sun illumination. More importantly, CHA can effectively suppress the evaporation of low-boiling-point contaminants including common pesticides and mercury ion via its strong adsorption and retention effect. Synergetic steaming and the adsorption of CHA will inspire more paradigms of solar steam generation technologies for applications relevant to detoxification and water remediation.

Polypyrrole‐Reinforced N,S‐Doping Graphene Foam for Efficient Solar Purification of Wastewater

Solar vapor generation is a sustainable and cost‐effective approach to addressing the issue of water shortage. However, the challenges of solar steam generation still exist for achieving a high evaporation efficiency combined with long‐term stability in the wastewater containing heavy metal ions and wide degrees of acidity and alkalinity (pH = 1–14). Herein, polypyrrole (PPy) loading on the N,S‐doped graphene oxide (N,S‐GO) foam is used for high‐efficiency solar evaporation of treating wastewater. With the advantages of excellent broadband solar absorption ( >97%), extremely low emissivity (0.70), and outstanding hydrophilicity, the N,S‐GO/PPy foam achieves a high evaporation efficiency of 90.5% under 1 sun illumination. More notably, the N,S‐GO/PPy foam has strong adsorption of heavy metal ions (Fe3+, Cu2+, and Cr6+) for treating wastewater synchronously evaporates at higher efficiencies of 94.7–98.4%. Interestingly, the high‐toxicity Cr6+ can be reduced to low‐toxicity Cr3+ effectively by the synergistic effect of N,S‐GO and PPy. In addition, the N,S‐GO foam shows a better long‐term resistance of acidity and alkalinity for 45 days. A new insight is offered into high‐efficiency solar evaporation for treating wastewater and water purification.

Revival of Traditional Cascade Tanks for Achieving Climate Resilience in Drylands of South India

Traditional tanks in arid regions of India have been working to address water demands of the public for more than 2000 years. However, recent decade is witnessing growing domestic and agricultural water demand coupled with rising encroachment and ignorance toward tanks; consequently, intensifying water shortage issues. While climate change is impacting at alarming rates, local agencies have forgotten these tanks that have aided in sustainable water supply solutions for decades apart from municipal water supply. This research, for the first time, estimates water supply-demand for an arid region in South India (Madurai) and lists out the benefits if tanks were managed and desilted. Exploratory investigations for documenting seasonal domestic and agricultural unmet water demand were conducted followed by their validation through ground-truthing across the study period 2002–2019. Results indicated high unmet domestic water demand, estimating ~73% [maximum 365 thousand cubic meters (TCM)] for summer (March to May) and ~33% (maximum 149 TCM) for winter (January and February), and high unmet agricultural water demand estimating ~90% (maximum 5,424 TCM) during North-East monsoon (October to December), and ~95% (maximum 5,161 TCM) during South-West monsoon (June to September). Erratic rainfall pattern was identified as a major cause for higher fluctuations in water availability inside tanks ranging 0–50%, while lack of ownership resulted in increased siltation load ranging 30–70% of the tank's volume. The study found that the major portion of the unmet water demand can be accounted for through rehabilitation of the tanks, as under the rehabilitated tank irrigation scenario the tank storage could attain 200–400% more water than the estimated agricultural water demand. It was concluded that if the cascade tanks were managed appropriately, they could have positive impacts by reducing floods and providing water for drought seasons.

High-Resolution Monitoring and Assessment of Evapotranspiration and Gross Primary Production Using Remote Sensing in a Typical Arid Region

Land surface evapotranspiration (ET) and gross primary productivity (GPP) are critical components in terrestrial ecosystems with water and carbon cycles. Large-scale, high-resolution, and accurately quantified ET and GPP values are important fundamental data for freshwater resource management and help in understanding terrestrial carbon and water cycles in an arid region. In this study, the revised surface energy balance system (SEBS) model and MOD17 GPP algorithm were used to estimate daily ET and GPP at 100 m resolution based on multi-source satellite remote sensing data to obtain surface biophysical parameters and meteorological forcing data as input variables for the model in the midstream oasis area of the Heihe River Basin (HRB) from 2010 to 2016. Then, we further calculated the ecosystem water-use efficiency (WUE). We validated the daily ET, GPP, and WUE from ground observations at a crop oasis station and conducted spatial intercomparisons of monthly and annual ET, GPP, and WUE at the irrigation district and cropland oasis scales. The site-level evaluation results show that ET and GPP had better performance than WUE at the daily time scale. Specifically, the deviations in the daily ET, GPP, and WUE data compared with ground observations were small, with a root mean square error (RMSE) and mean absolute percent error (MAPE) of 0.75 mm/day and 26.59%, 1.13 gC/m2 and 36.62%, and 0.50 gC/kgH2O and 39.83%, respectively. The regional annual ET, GPP, and WUE varied from 300 to 700 mm, 200 to 650 gC/m2, and 0.5 to 1.0 gC/kgH2O, respectively, over the entire irrigation oasis area. It was found that annual ET and GPP were greater than 550 mm and 500 gC/m2, and annual oasis cropland WUE had strong invariability and was maintained at approximately 0.85 gC/kgH2O. The spatial intercomparisons from 2010 to 2016 revealed that ET had similar spatial patterns to GPP due to tightly coupled carbon and water fluxes. However, the WUE spatiotemporal patterns were slightly different from both ET and GPP, particularly in the early and late growing seasons for the oasis area. Our results demonstrate that spatial full coverage and reasonably fine spatiotemporal variation and variability could significantly improve our understanding of water-saving irrigation strategies and oasis agricultural water management practices in the face of water shortage issues.

Willingness To Pay Konsumen Pengguna Air Di Sub-Das Kali Dendeng – Kota Kupang

Global awareness towards climate change has been a serious concern for archipelago countries due to water shortage. This problem even causes more serious life-threating phenomenon because water is one of the main resources for energy circulation. Whether change anomalies have brought about impacts on seasonal shift on several islands of Indonesia, including those in East Nusa Tenggara province. These islands experience drought. Fresh water availability for industry and domestic use in cities like Kupang has been a serious problem. This issue becomes worse in recent years due to significant increase of city population. Public responsibility to maintain natural environment and resources is therefore required. This study tries to investigate public concerns over the water shortage issue in order (1) to know to what extent public is willing to pay their consumption of fresh water provided through Sub-DAS Kali Dendeng; and (2) to analyze factors that influence the willingness of the fresh water consumers to pay for environment services provided at Sub-DAS Kali Dendeng. Quantitative approach which relies on primary and secondary data gathered through interview and field observation is applied in this study. The data were analyzed by using Dichotomous Choice CVM, Turnbull Method, and Logistic Regression to find out WTP value. The results of this analysis are described within the environmental science perspective to find out the relationship among various factors for being water consumer responsibility towards water resources preservation at Sub-DAS Kali Dendeng in Kupang. The results of the analysis show that the willingness to pay for fresh water by consumer at Kelurahan Manutapen, Mantasi dan Airmata is significantly high. They are willing to pay between Rp. 3.362 to Rp.11.328 according to WTP calculation. This amount is much higher than that determined by the city freshwater supplier company (PDAM). The facts for the reason why the consumers are willing to pay for higher amount for fresh water supply are determined by several factors; they include bidding value, consumer’s level of education, consumer’s income, water quality, and the amount of the family members. These factors simultaneously influence the water consumer willingness to pay for the water they consume; and this willingness factor has significantly high impacts as seen in Negelkerke R. Square value at 0,600, or being comparable to 60%; meaning that various factors of 60% in Y are able to explain all free variable in X. Respondents for this study are those who use fresh water supplied from Sub-DAS Kali Dendeng, and those who reside around the Sub-DAS Kali Dendeng. It is believed that there must be more citizens around the Sub-DAS Kali Dendeng, who also contribute negative impact toward the ecological environmental change, yet these individuals have no direct responsibility, and therefore the responsibility for the environmental conservation examined trough this study might not be thoroughly measured by the amount of WTP they pay.

A scalable broadband plasmonic cuprous telluride nanowire-based hybrid photothermal membrane for efficient solar vapor generation

Abstract Solar vapor generation utilizes ubiquitous solar energy to address the issue of global water shortage. However, its large-scale field deployment is greatly hampered by inefficient solar absorption, moderate evaporation efficiency and high cost. Here, we report a new hybrid photothermal membrane, named broadband plasmonic Cu2−xTe nanowire (bpCu2−xTe) membrane, for interfacial solar evaporation to produce freshwater from various water sources. The bpCu2−xTe membrane features excellent broadband solar absorption (~95.9%), high porosity and hydrophilicity, and low thermal conductivity (0.55 W/(m K)), which enables a water evaporation rate as high as 4.3 kg/(m2 h) with the evaporation efficiency of up to 96% under 3 kW/m2 solar irradiation. The evaporation performance of the present Cu2−xTe membrane can be maintained even after it recycles multiple times under various solar irradiance, indicating excellent durability and stability. Efficient solar desalination of seawater is further demonstrated with the bpCu2−xTe membrane to deliver drinkable water. The combination of scalable fabrication ability, low cost and excellent solar evaporation performance of the bpCu2−xTe membrane highlights the potential for seawater purification and desalination in field applications.

Mitigation of the Water Crisis in Sub-Saharan Africa: Construction of Delocalized Water Collection and Retention Systems

This paper presents the results of a three-year research project aimed at addressing the issue of water shortage and retention/collection in drought-affected rural areas of Sub-Saharan Africa. The project consisted in the design, construction, and the upgrade of existing barrages near Kita, the regional capital of Kayes in Mali. The effort was led by the Department of Architecture of Roma Tre University in partnership with the Onlus Gente d’Africa (who handled the on-the-ground logistics), the Department of Architecture of the University of Florence and the École Supérieure d’Ingénierie, d’Architecture et d’Urbanisme of Bamako, Mali. The practical realization of the project was made possible by Romagna Acque Società delle Fonti Ltd., a water utility supplying drinking water in the Emilia-Romagna region (Italy) that provided the financing as well as the operational contribution of AES Architettura Emergenza Sviluppo, a nonprofit association operating in the depressed areas of the world. The completion of the research project resulted in the replenishment of reservoirs and renewed presence of water in the subsoil of the surrounding areas. Several economic activities such as fishing and rice cultivation have spawned from the availability of water. The monitoring of these results is still ongoing; however, it is already possible to assess some critical issues highlighted, especially with the progress of the COVID-19 pandemic in the research areas.

CoWO4-x -Based Photothermal Membranes for Solar-Driven Water Evaporation and Eutrophic Lake Water Purification.

Solar-driven water evaporation has been proven to be a promising and efficient method for the energy crisis and clean water shortage issues. Herein, we strategically design and fabricate a novel nonstoichiometric CoWO4–x-deposited foam nickel (NF) membrane (CoWO4–x@NF) that possesses all the desirable optical, thermal, and wetting properties for efficient water evaporation and purification. The broadband absorption of CoWO4–x nanoparticles (NPs) obtained by hydrogen reduction contributes to light-to-heat conversion, while NF with a three-dimensional porous structure can support CoWO4–x NPs and ensure the rapid flow of water molecules during the water evaporation process. We systematically explore and compare the outdoor water evaporation performance of the pure water group, NF group, and CoWO4–x@NF group, and the results show that CoWO4–x@NF performs well under natural sunlight irradiation (water evaporation: 2.91 kg m–2). Significantly, under solar irradiation, the remarkable reduction of Cyanophyta and Euglenophyta in lake water is achieved in the CoWO4–x@NF membrane-administered group, and these two algae are the main factors for eutrophication of the lake water. Our work highlights the great potentials of the CoWO4–x@NF membrane as a device for realizing outdoor solar energy-driven water evaporation and proposes a new strategy for purifying the eutrophication of the lake water.

Drivers of dynamic evolution in provincial production water usage: perspective of regional relevance.

With the advancement of industrialization and urbanization, the issue of water shortage has become a bottleneck for China's economic development. Based on the structural decomposition analysis and multi-regional input-output tables of China in 2002 and 2012, this paper explores the drivers of the change in China's production water usage from the regional relevance perspective. Results show a significant increase in China's production water usage during the study period. The relationship between production water usage and per capita GDP shows an inverted U-shaped curve, and the economic scale by provinces has been improved, while the trend of production water usage differs. There are rapid increases in production water usage in economically developing provinces, while it is falling sharply in developed provinces. The crucial factors promoting its growth are changes in consumption level, population scale, and regional economic patterns. The technical effect is the most important factor in curbing the growth, followed by effects of final demand sectoral and distribution structure. The provinces and sectors with more production water usage shows higher technical and final demand effects. Therefore, it is necessary to promote water-saving activities, enhance the water-saving technical effect, and optimize final demand structure to promote economic growth with low-water usage.

A Low-Impact Development–Based Multi-Objective Optimization Model for Regional Water Resource Management under Impacts of Climate Change

Under the urgency of rational water resource allocation and effective urban flooding control, a multi-objective interval birandom chance-constrained programming (MIBCCP) model is developed for supporting regional water resource management under multiple uncertainties and climate change in this study. Two objectives were included in this model, which are the minimization of total system costs and the maximization of total pollutant-treatment amounts, respectively. The major advantage of proposed MIBCCP model is that it realized the effective combined utilization of conventional and nonconventional water sources under complexities and uncertainties through incorporating compromise programming (CP), birandom chance-constrained programming (BCCP) and interval linear programming (ILP) within a general framework. This way effectively overcome water-shortage issue and reduced urban flood frequency under climate change. A water supply management system of the educational park in Tianjin was used as a study case for demonstration. A variety of adaptive water allocation alternatives and construction schemes for LID projects under RCP4.5 and RCP8.5 (representative concentration pathway 4.5 and 8.5) scenarios were obtained to deal with possible changes arising from increasing rainfall and runoff in the future. It is concluded that proposed MIBCCP model provided the effective linkage between the utilization of nonconventional water resources and urban flood prevention, and offered insights into the tradeoff between economic benefits and environmental protection.

The role of natural resources in economic growth: new evidence from Pakistan

Purpose The purpose of this study is to investigate the role of natural resources in economic growth by taking evidence from Pakistan. Design/methodology/approach Total five variables are used in this study, i.e. GDP, population density, water renewable resources, deforestation and the emissions of CO2, based on time series data from 1972 to 2016. The annual data is collected from World Development Indicators, Food and Agriculture Organization and Pakistan Economic Survey. Vector error correction model technique is applied to find out the long-run results. Findings Results depict that all variables have a negative and significant relationship over the long run at 5% level of significance. It is observed that 1% increase in population accordingly will degrade GDP by 0.334496%. Correspondingly, 1% increase of water renewable resources will degrade GDP by 0.450647%. Findings are aligning with the study of. Moreover, 1% increase in deforestation will diminish GDP by 0.127821%. If we increase 1% of CO2, GDP will be reduced by 0.802420%. Research limitations/implications Results depict that all variables have a negative and significant relationship over the long run at 5% level of significance. It is observed that 1% increase in population accordingly will degrade GDP by 0.334496%. Correspondingly, 1% increase of water renewable resources will degrade GDP by 0.450647%. Findings are aligning with the study of. Moreover, 1% increase in deforestation will diminish GDP by 0.127821%. If we increase 1% of CO2, GDP will be reduced by 0.802420%. Practical implications Family planning may be our last hope. Viable and fruitful family planning ought to be introduced. Status of ladies should be brought up in the society by providing education and employment opportunities. Time of marriage ought to be brought up to 25 years in case of males and 23 in case of females; this can help in decreasing the number of births. Having a large population will not automatically translate into economic prosperity. Investment in well-being, education, sound economic policies and good governance will bring about accelerated economic growth. Originality/value In recent years, the issue of worldwide water shortage has attracted increasing consideration within scholarly community, non-administrative organizations and the media. Water shortage is a significant and ever-increasing danger to the environment, human well-being, advancement, energy security and the worldwide food supply. This work will introduce real issues and requirements relating to water, environmental changes and their impact on economic growth of Pakistan.

Functional oil-repellent photothermal materials based on nickel foam for efficient solar steam generation

The production of fresh water by means of solar steam generation has emerged as one of frontier technologies for addressing the global water shortage issue. Here, we report the preparation of new photothermal materials by chemical modification of nickel foam with sulfur via a simple hydrothermal method for solar steam generation. The generation of nano nickel wire on the surface of skeleton of nickel foam by sulfur treatment could construct a much more dense network with hierarchical porous structure and hydrophilicity, which significantly enhance their light absorption (average 40–50% for untreated nickel foam while 91% for sulfur treated nickel foam (named as S–Ni foam) as well as water transportation. In the way, the as-prepared S–Ni foam possesses a high energy conversion efficiency of 83.6% under 1 kW m−2 irradiation. In view of most of reported photothermal materials which suffer the drawback of lose effectiveness in oily water, the S–Ni foam was further chemically modified with an anionic coordination between sodium perfluorooctanoate (PFO) and poly diallyl dimethyl ammonium (PDDA) chloride to achieve a strong hydrophilic-oleophobic wettability (named as OR-S-Ni foam). Such unique wettability endows the as-resulted OR-S-Ni foam excellent oil-repellent performance, making it possible solar vaporization even in water containing oils or organics contaminates, which should be of significantly technological significance for practical solar steam generation by largely extends its applications range.

Experimental investigation of underground seasonal cold energy storage using borehole heat exchangers based on laboratory scale sandbox

In order to overcome the intermittent nature of renewable energy resources, borehole thermal energy storage (BTES) systems are found to be a feasible option these days. Previous research data shows that most of the BTES projects are related to heat storage and there are very few underground cold storage applications. The proposed research work is based on the experimental strategy to determine the extracted energy storage potential in typical weather condition areas. It emphasizes on the mathematical model for soil extracted energy storage system and derives similar function relationship of soil TES system based on similarity theory. A laboratory-scale sandbox is designed with similar scale factor n = 20. Sandbox system is operated in peak winter months from October to March according to the weather data for Dunhuang, China. Approximately 69 % of the input energy is charged into the soil. Soil temperature is reduced up to 11 °C during the extraction period. The maximum heat flux value is recorded 65 W.m−2. The experimental results reveal the practicality of proposed research method. It can be used to fulfill cooling load requirements for air conditioning systems and solar thermal power plants located in desert areas with water shortage issues.

Graphene and Rice-Straw-Fiber-Based 3D Photothermal Aerogels for Highly Efficient Solar Evaporation.

Solar-steam generation is one of the most promising technologies to mitigate the issue of clean water shortage using sustainable solar energy. Photothermal aerogels, especially the three-dimensional (3D) graphene-based aerogels, have shown unique merits for solar-steam generation, such as lightweight, high flexibility, and superior evaporation rate and energy efficiency. However, 3D aerogels require much more raw materials of graphene, which limits their large-scale applications. In this study, 3D photothermal aerogels composed of reduced graphene oxide (RGO) nanosheets, rice-straw-derived cellulose fibers, and sodium alginate (SA) are prepared for solar-steam generation. The use of rice straw fibers as skeletal support significantly reduces the need for the more expensive RGO by 43.5%, turning the rice straw biomass waste into value-added materials. The integration of rice straw fibers and RGO significantly enhances the flexibility and mechanical stability of the obtained photothermal RGO-SA-cellulose aerogel. The photothermal aerogel shows a strong broad-band light absorption of 96-97%. During solar-steam generation, the 3D photothermal aerogel effectively decreases the radiation and convection energy loss while enhancing energy harvesting from the environment, leading to an extremely high evaporation rate of 2.25 kg m-2 h-1, corresponding to an energy conversion efficiency of 88.9% under 1.0 sun irradiation. The salinity of clean water collected during the evaporation of real seawater is only 0.37 ppm. The materials are environmentally friendly and cost-effective, showing great potential for real-world desalination applications.

The Impact of Virtual Water on Sustainable Development in Gansu Province

The concept of virtual water, as a new approach for addressing water shortage and safety issues, can be applied to support sustainable development in water-scarce regions. Using the input-output method, the direct and the complete water use coefficients of industries categorized as primary, secondary, or tertiary, and the spatial flow patterns of the inter-provincial trade in the Gansu province region of China, were explored. The results show that in 2007, 2010, and 2012 the direct and complete water use coefficients of the primary industries were the greatest among the three industry categories, with direct water use coefficients of 1545.58, 882.28, and 762.16, respectively, and complete water use coefficients of 1692.22, 1005.38, and 873.44, respectively; whereas, the direct and complete water use coefficient values of the tertiary industry category were the lowest, with direct water use coefficients of 16.65, 7.74, and 66.89 for 2007, 2010, and 2012, respectively, and complete water use coefficients of 65.46, 66.89, and 72.81 for 2007, 2010, and 2012, respectively. In addition, study results suggest that the volume of virtual water supplied to Gasnu province’s local industries has decreased annually, while virtual water exports from the province have increased annually, with the primary industry accounting for 95% of virtual water output. Overall, the virtual water of Gansu province in 2010 showed a net output trend, with a total output of 0.506 billion m3, while in 2007 and 2012 it showed a net input trend with a total input of 0.104 and 1.235 billion m3, respectively. Beijing, Shanghai, Guangdong, Ningxia and other water-scarce areas were the main input, or import source for Gansu’s virtual water; during the years studied, these provinces imported more than 50 million m3 individually. Based on these results, it is clear that under the current structure, virtual water is mainly exported to the well-developed coastal areas and their adjacent provinces or other water-abundant regions. Therefore, Gansu province should (1) adjust the industrial structure and develop water-saving and high-tech industries; (2) adjust the current trade pattern to reduce virtual water output while increasing its input to achieve balanced economic development and water resource security.

Synergetic conservation of water and energy in China's industrial sector: From the perspectives of output and substitution elasticities

China's rapid industrialization has induced water and energy shortage issue. Since water and energy resources are inextricably connected, the synergetic conservation of these two resources is conducive to China's sustainable development. In this paper, using a heterogeneous stochastic frontier model, we estimate the output and substitution elasticities of water and energy in China's industrial sector at the provincial level during the period of 2004–2014, in order to explore how to achieve synergetic conservation of water and energy resources by identifying the water-energy nexus. The results show that in China's industrial sector, the overall technical efficiency measured by the ratio of actual output to the ideal output in production frontier experienced a slight decline during the research period. The output elasticity (i.e., the changes in output caused by per unit change in a certain input) of water remains positive, while that of energy is negative in most years, indicating that water input increase contributes to industrial output growth, rather than energy input. Water and energy show a complementary relationship in most years, suggesting that a decrease in water input can reduce energy input. Therefore, to achieve the synergetic conservation of water and energy, the government should actively advance water-saving and energy-saving technologies by taking account of the differentiated production characteristics of different provincial-level industrial sector. In particular, when water and energy are complementary, the technological progress for saving either energy or water will be conducive to the synergetic conservation of these two resources.

Multi-objective optimization for solving water shortage issues in arid zones via the analytic hierarchy process (AHP): the Israeli case

Multi-objective optimization for solving water shortage issues in arid zones via the analytic hierarchy process (AHP): the Israeli case

Performance enhancement of waste heat extraction from generator of a wind turbine for freshwater production via employing various nanofluids

Water shortage issues are growing through the globe at higher rate than population growth. On the bright side, various methods are devised to capture energy from renewable energy or waste heat from different sectors. Among all inspected approaches, waste heat capturing through cooling process of the wind turbines' generators for desalination at small scale is paid less attention. However, in large wind farms, the scale of this dissipated thermal heat becomes appreciable which can drive several desalination units.Due to the above-pointed facts, the waste heat of a wind turbine with nominal capacity of 7358 kW and height of 24 m for desalinating seawater is inspected here, using a humidification-dehumidification (HDH) unit. Also, five nanoparticles of Cu, CuO, TiO2, Al2O3, and SiO2 with base fluid of water are used through the cooling process of the wind turbine's generator in order to produce more freshwater. The devised set-up is evaluated in terms of the first and second laws of thermodynamics for different selected nanofluids. It is found that wind turbine has the highest exergy destruction of 1125 kW, followed by heater. Also, the total exergy destruction (for all nanofluids) is calculated approximately 1387 kW. Also, among all employed nanoparticles, Cu/water mixture has the highest performance since it produces more freshwater, while SiO2/water mixture has the lowest performance. Moreover, the total energy efficiency reaches its maximum value in the range of 26.25–26.5% at wind speed of 11.5 m/s.