Non-conventional Water Resources Research Articles

The Analysis of Present and Future Use of Non-Conventional Water Resources in Heilongjiang Province, China

Analyzing the development trend of non-conventional water resources and identifying the main influencing factors is the initial step toward rapidly increasing the utilization and allocation of these resources in a rational and scientific manner. This will help relieve pressure on water resources and improve the ecological environment. This study introduces the concept of comparison testing and employs advanced Dematel and Random Forest models to identify two sets of optimal indicators from a pool of nine. Based on the two best indicator sets, three prediction models—BP neural network, Particle Swarm Optimization-optimized BP neural network, and Genetic neural network—were used to forecast the future potential of non-conventional water resource use in Heilongjiang Province. The findings reveal that economic indicators are the most significant factors influencing Heilongjiang Province’s utilization of non-conventional water resources. The findings of this study help us understand the extent of development in utilizing non-conventional water resources.

Opportunities for membrane technology in controlled environment agriculture

Controlled environment agriculture has the potential to enhance agriculture sustainability, a United Nations sustainable development goal. Enclosed agricultural facilities can be used in locations that cannot support field agriculture while reducing water usage and increasing productivity relative to open field agriculture. The primary challenges with operation arise from energy consumption to maintain the proper growth conditions. Membrane processes can reduce energy consumption by controlling temperature, humidity, and carbon dioxide concentration. Membrane processes also can minimize water consumption by enabling the use of non-conventional water resources and reducing wastewater production. The literature describing these applications is reviewed and opportunities for future innovation are discussed.

The Importance of Nonconventional Water Resources under Water Scarcity

According to FAO, water scarcity is now affecting all five continents and is expected to intensify in the coming years as the water demands of the growing population increase and the impacts of climate variability become more pronounced. The existing unevenness of water resource availability and insufficient investment in relevant infrastructure have forced the water sector to recognize the importance of nonconventional water resources (NWR) in planning for a sustainable water future. The purpose of this review is to highlight the available and potentially available NWR and to discuss the future application of these water sources.

Are Non-Conventional Water Resources the Solution for the Structural Water Deficit in Mediterranean Agriculture? The Case of the Segura River Basin in Spain

The water sustainability of the Segura River Basin (SRB), located in southeastern Spain, is being challenged as conventional available water sources fall short of meeting the authorised demands of the basin. In recent years, non-conventional water (NCW), such as desalinated and reclaimed water, has become part of the resource pool. However, it has not yet become crucial for irrigation water supply due to its relatively high cost and lower quality compared to conventional water. The new political framework in Spain, developed in the context of ecological transition, marks a notable shift for non-conventional water as a strategic resource for agriculture. This study examines the drivers and barriers influencing its acceptance through an analysis of farmers’ perceptions, conducted through interviews with twelve irrigation communities’ (ICs) representatives of the basin. Discriminant analyses of the data show that the farmers’ experience, along with factors pertaining to production, storage, and transportation costs, determines the acceptance and use of NCW.

The Performance and Feasibility of Solar-Powered Desalination for Brackish Groundwater in Egypt

With a deficit of about 20 BCM in 2022, Egypt faces a severe water shortage due to rapid population growth (109.3 million in 2022). Egypt launched a program to utilize non-conventional water sources, like treated wastewater, agriculture drainage water, and desalination. Egypt is expanding its non-conventional water resources, boosting desalination capacity from 86,000 m3/day in 2015 to 680,000 m3/day in 2022, with plans to reach 1,250,000 m3/day by 2025. Despite the improvements in desalination technologies and cost, its high energy use and environmental impacts are still limiting its use. Egypt’s desalination relies on grid electricity, but renewable energy is crucial for remote areas where no electricity grid exists. Scaling up renewable energy in desalination faces challenges like land availability and high costs. GIS was used for optimal site selection for a brackish groundwater solar desalination plant in the Western North Nile Delta. Factors like solar radiation, groundwater quality, aquifer potentiality, geology, and seawater intrusion were carefully assessed. An evaluation of a sustainable 1000 m3/day solar-powered RO desalination pilot plant’s economic and technical viability is provided, along with its performance assessment. Limitations, challenges, and potential improvements are discussed. The study finds that RO–PV desalination for brackish groundwater is technically mature, with competitive Capex costs (USD 760-USD 850/m3) and low Opex (USD 0.55–USD 0.63/m3). Solar desalination for brackish groundwater with salinity less than 23,000 ppm can reduce energy consumption to 3.6–4.2 kWhr/m3. Water storage and hybrid systems with solar and conventional energy are suggested to enhance efficiency. This implies a growing market for small- to medium-scale RO solar-powered desalination in remote areas in the near future.

Treated water from oil and gas extraction as an unconventional water resource for agriculture in the Anadarko Basin

The energy industry generates large volumes of produced water (PW) as a byproduct of oil and gas extraction. In the central United States, PW disposal occurs through deep well injection, which can increase seismic activity. The treatment of PW for use in agriculture is an alternative to current disposal practices that can also provide supplemental water in regions where limited freshwater sources can affect agricultural production. This paper assesses the potential for developing PW as a water source for agriculture in the Anadarko basin, a major oil and gas field spanning parts of Kansas, Oklahoma, Colorado, and Texas. From 2011 to 2019, assessment of state oil and gas databases indicated that PW generation in the Anadarko Basin averaged 428 million m3/yr. A techno-economic analysis of PW treatment was combined with geographical information on PW availability and composition to assess the costs and energy requirements to recover this PW as a non-conventional water resource for agriculture. The volume of freshwater economically extractable from PW was estimated to be between 58 million m3 per year using reverse osmosis (RO) treatment only and 82 million m3 per year using a combination of RO and mechanical vapor compression to treat higher salinity waters. These volumes could meet 1–2 % and 49–70 % of the irrigation and livestock water demands in the basin, respectively. PW recovery could also modestly contribute to mitigating the decline of the Ogallala aquifer by ~2 %. RO treatment costs and energy requirements, 0.3–1.5 $/m3 and 1.01–2.65 kWh/m3, respectively, are similar to those for deep well injection. Treatment of higher salinity waters increases costs and energy requirements substantially and is likely not economically feasible in most cases. The approach presented here provides a valuable framework for assessing PW as a supplemental water source in regions facing similar challenges.

Towards Sustainable Water Resources Management Considering Climate Change in the Case of Saudi Arabia

Saudi Arabia is one of the most water-scarce nations in the world, with a huge demand-supply gap, and the situation is expected to worsen due to climate change. Conventional surface water resources are limited, while nonrenewable groundwater sources are depleted. To build a more resilient and sustainable water sector, the production of non-conventional water resources, specifically desalinated seawater and treated domestic wastewater, has steadily increased in recent years. As the country lacks perennial water resources, such as rivers or water bodies, it relies mainly on nonrenewable groundwater and desalinated water to meet its daily requirements. Although the government is attempting to regulate the agricultural sector, water consumption in agriculture remains relatively high. It presents an environmental challenge due to its heavy reliance on non-renewable groundwater resources. The anticipated increase in temperature and highly uncertain changes in the rainfall patterns in Saudi Arabia could lead to greater uncertainty when attempting to develop effective water resource management plans. In this work, we review the status of the present and future of water resources and the challenges local authorities face in managing water resources amidst a changing climate in Saudi Arabia. This study employed a narrative research methodology, utilizing various databases, including Scopus, Web of Science, and Science Direct, to extract relevant articles within the subject area. This study proposes a number of recommendations and conclusions aimed at improving decision-makers’ ability to adapt to and mitigate the anticipated adverse impacts of climate change to manage scarce water resources sustainably.

The advent of EU water reuse regulation in the Mediterranean region: policy and legislative adaptation to address non-conventional water resources utilization in agriculture

ABSTRACTThe provision of safe, sustainable and accepted ways of water supply for the Mediterranean basin by using non-conventional water resources is key to reducing the gap between agricultural water demand and supply. The article offers a review of the current policy and legislative frameworks addressing non-conventional water resources in agriculture in selected Mediterranean countries, including non-European Union countries. A particular focus is put on the EU Water Reuse Regulation of 2020. By combining a literature review and stakeholders’ consultations, this study offers different visions from EU countries and non-EU countries around the Mediterranean which might be affected by the regulation.

Photothermal-photocatalytic route of MOF-based membrane with nanosheet array structures for solar-driven water purification

Solar-driven interfacial evaporation technology is a promising sustainable approach to mitigate the global energy crisis and clean water scarcity. The advanced interfacial evaporation materials make a non-negligible contribution to the solar thermal utilization for water purification. In this work, a Cu-catecholate metal–organic framework-based photothermal membrane (Cu-CATM) is developed to generate freshwater from seawater and recover clean water from wastewater. Thanks to the unique photothermal effect and the three-dimensional nanosheet array structure of Cu-catecholate metal–organic framework (Cu-CAT MOF), the Cu-CATM enabled a promising evaporation rate of 2.43 kg m−2h−1 and a high solar-vapor conversion efficiency of 92% under solar irradiance of 1 sun. Further, the Cu-CATM could be applied to solar seawater desalination with durable evaporation rate and no salt accumulation. Also, the Cu-CATM enabled solar utilization for synchronous photothermal desalination and photocatalytic degradation, which highlighted the broader environmental application for water remediation or wastewater treatment via photothermal-photocatalytic route. This work presents a viable and effective route for the development of photothermal membranes toward future sustainable clean water production from non-conventional water resources.

Socioeconomic, environmental, and health impacts of reusing treated wastewater in agriculture in some Arab countries, including occupied Palestine, in view of climate change

The increase in water stress and shortage, facing many countries around the world, is one of the main difficulties confronting practical progress and sustainable development and management. Accordingly, managing the water assets of many countries around the world is nowadays a big challenge due to immense difficulties and vulnerabilities, including rapid industrialization and urbanization processes, population growth, geopolitical instability, and the effects of environmental changes, namely global warming and climate change. Because of global fresh waters scarcity and shortage, the demand for using non-conventional water resources, such as reusing treated wastewater for irrigation and industrial purposes, has become a nessitiy. However, the reuse of effluents for agricultural irrigation can have negative impacts on crop quality and soil conditions, as well as on public health and the environment. Moreover, improper management of agricultural irrigation with treated wastewater can also cause problems for plant production and soils’ physical and chemical propeties. This paper investigates the status of freshwater and wastewater in view of climate change, and socioeconomic, environmental, and health impacts of reusing treated wastewater for irrigation in the Arab region, with the focus on the Occupied Palestinian Territories (OPT), as an example. The paper concludes that: 1) Approximately 13.2 billion cubic meters (BCM) of wastewater is yearly produced in the Arab countries, of which 5.7 BCM (43.2%) is treated and 7.5 MCM (56.8%) is untreated and dumped in open environments; 2) Regarding the OPT, where more than 87% of its fresh water resources are controlled and forcefully taken by the Israeli occupation authorities, Palestinians discharge large amounts of untreated wastewater into open lands (as in the case of the occupied West Bank) and in the Mediterranean Sea (as in the case of occupied and besieged Gaza Strip); and 3) The reused portion of treated wastewater in the OPT is close to zero.

Water desalination in Egypt; literature review and assessment

The increasing demand for water in urban and industrial areas in arid and semiarid coastal zones has led to the search for alternative nonconventional water resources.. Desalination plants are the most feasible solution to the huge water demand in arid regions, especially in Egypt, with its limited water resources of the Nile River and expected drought due to climate change and upstream dam construction. Many desalination technologies, such as thermal and membrane technologies, are used. Thermal desalination includes multistage flash desalination, multi-effect desalination, and desalination by vapor compression. Membrane desalination involves RO, forward osmosis, and electro dialysis. (RO) desalination plants are the most significant technique for desalinated water in Egypt. However, the treatment of brine wastewater is still a challenging problem. Hypersaline water effluent, as a byproduct of seawater desalination, has a negative impact on the marine ecosystem if it is discharged inadequately. In the past decade, Egypt has launched many large-scale projects along Red Sea and Mediterranean coasts to cope the recent economic growth. In this research a review of taxonomy of many related publications, and comparison has been made between the different seawater desalination techniques to determine the advantages and disadvantages of each of them, as well as to know the best technology that can be used in Egypt. The Egyptian state's plan to address the excessive demand for water resources as a result of the continuous population growth was reviewed by making a strategic plan for 30 years. It was divided into five-year plans, some parts of which have been completed, and the rest of the plan is being completed to present significant comparisons and enable the derivation of informative conclusions.

Response of Soil Microenvironment and Crop Growth to Cyclic Irrigation Using Reclaimed Water and Brackish Water.

The scarcity of freshwater resources has increased the use of nonconventional water resources such as brackish water, reclaimed water, etc., especially in water-scarce areas. Whether an irrigation cycle using reclaimed water and brackish water (RBCI) poses a risk of secondary soil salinization to crop yields needs to be studied. Aiming to find an appropriate use for different nonconventional water resources, pot experiments were conducted to study the effects of RBCI on soil microenvironments, growth, physiological characteristics and antioxidation properties of crops. The results showed the following: (1) compared to FBCI, the soil moisture content was slightly higher, without a significant difference, while the soil EC, sodium and chloride ions contents increased significantly under the RBCI treatment. With an increase in the reclaimed water irrigation frequency (Tri), the contents of EC, Na+ and Cl- in the soil decreased gradually, and the difference was significant; the soil moisture content also decreased gradually. (2) There were different effects of the RBCI regime on the soil's enzyme activities. With an increase in the Tri, the soil urease activity indicated a significant upward trend as a whole. (3) RBCI can alleviate the risk of soil salinization to some extent. The soil pH values were all below 8.5, and were without a risk of secondary soil alkalization. The ESP did not exceed 15 percent, and there was no possible risk of soil alkalization except that the ESP in soil irrigated by brackish water irrigation went beyond the limit of 15 percent. (4) Compared with FBCI, no obvious changes appeared to the aboveground and underground biomasses under the RBCI treatment. The RBCI treatment was conducive to increasing the aboveground biomass compared with pure brackish water irrigation. Therefore, short-term RBCI helps to reduce the risk of soil salinization without significantly affecting crop yield, and the irrigation cycle using reclaimed-reclaimed-brackish water at 3 g·L-1 was recommended, according to the experimental results.

Janus film evaporator with improved light-trapping and gradient interfacial hydrophilicity toward sustainable solar-driven desalination and purification

Solar-driven desalination and purification offers a promising approach to water treatment, while the clean water yields under natural sunlight can be further increased by developing well-designed evaporators. Herein, a TiN/GO//GO Janus film was fabricated to realize the synergetic effect of effective photothermal conversion and water transportation. The top TiN/GO hybrid layer possesses high solar absorption and thermal conversion efficiency, while the bottom GO layer promotes expeditious water transport. Moreover, the film maintains gradient interfacial hydrophilicity due to the reservation of oxygen-functional groups, which facilitate the formation of thin liquid film at water-film interface and increase heat utilization efficiency. Therefore, the Janus film is demonstrated to possess high evaporation rate of 1.70 kg m−2 h−1 for various non-conventional water resources under 1 solar illumination, which is comparable or better than most of the film evaporators. The excellent durability is demonstrated in a wide acid–base range (pH 2–11) and salinity range (0–250‰) over 30 cycles. The outdoor device with Janus film exhibits daily water yield of 7.44 kg m−2, indicating a potential application in efficient solar-driven desalination and non-conventional water treatment.

Towards the Adoption of Non-conventional Water Resources (Green and Grey Condensation): The Case of Egypt

This research evaluates the dependency between air conditioner water and rainwater as a solution to water scarcity in Egypt. A sample from rain and air conditioner water has been collected in Cairo for lab testing. Also, an experiment involving a 1-tonne air conditioner has been conducted to estimate the volume of output water from the air conditioner. Moreover, a study of the meteorological data of El Shorouk City and the potential for water capture and reuse have been estimated. The British University in Egypt (BUE) has been taken as a case study to evaluate the amount of water per year that can be generated if the aforementioned two water sources are used. The lab testing results of rain and air conditioner water indicated that both had a slightly acidic nature with low mineral content. However, both samples meet standards for irrigation of crops and non-potable uses set by the Egyptian Decree of Health Ministry (No. 458) (2007). As for BUE, the amount of water that may be collected from air conditioners and rainfall was estimated at 1523.45 m³ and 8065 m³ per year, respectively. This water may be used for irrigation of green areas, distilled water for soil and concrete labs, or cleaning purposes.

Novel concept for water scarcity quantification considering nonconventional and virtual water resources in arid countries: Application in Gulf Cooperation Council countries

The lack of perennial streams or surface water in most arid countries necessitates input modification and water scarcity/security equation calculation as per the water resource systems and physiographic conditions in these countries. The contributions of nonconventional and virtual water resources to water security have been disregarded or undervalued in previous research on global water scarcity. This study addresses this knowledge gap by developing a new framework for estimating water scarcity/security. The proposed framework considers the contributions of unconventional and virtual water resources and the roles of economics, technology, water availability, service accessibility, water safety and quality, water management, and resilience to threats on water and food security, and considers institutional changes required to adjust to water scarcity. To manage water demand, the new framework incorporates metrics for all categories of water resources. Although the framework was specifically designed for arid regions, particularly the Gulf Cooperation Council (GCC) countries, it is applicable to non-arid nations too. The framework was implemented in GCC countries, which are suitable examples of arid countries with notable virtual commerce. The ratio of abstraction from freshwater resources to renewability from conventional water sources was calculated to determine the extent of water stress in each country. The values obtained from measurement varied from 0.4 (the optimal threshold level for Bahrain) to 22 (severe water stress/low water security in Kuwait). Considering the nonconventional and abstracted nonrenewable groundwater volumes from the total water demand in the GCC, the minimum water stress value measured was 0.13 in Kuwait, suggesting considerable reliance on nonconventional water resources along with little domestic food production to achieve water security. The novel water scarcity/stress index framework was found to be appropriate for arid and hyper-arid regions, such as the GCC, where virtual water trade has a major positive impact on water security.

Water budget-salt balance model for calculating net water saving considering different non-conventional water resources in agricultural process

Iraq is facing a dire water crisis due to the decrease in water quantities flow in Tigris and Euphrates Rivers. Due to population growth, several studies estimated the water shortage in 2035 to be 44 Billion Cubic Meter (BCM). Thus, Water Budget-Salt Balance Model (WBSBM) has been developed, applied and examined for the Euphrates River basin to compute the net water saving from Non-Conventional Water Resources (NCWRs). WBSBM includes 4-stages; the first is to identify the required data correspond to the conventional water resources in the study-area. The second stage is demonstrating the water-users activities. Thirdly, develop model through the proposed NCWR projects that reflect the required data. The final stage involves net water saving computation while applying all the NCWR projects simultaneously. The results obtained the optimal potential net water saving amount, which are 6.823 and 6.626 BCM/year in 2025 and 2035, respectively. In conclusion, the proposed WBSBM model has comprehensively examined different scenarios of utilizing NCWRs and has determined the optimal potential the net water saving amounts.

Sensitivity Analysis for Multi-Criteria Decision Analysis Framework for Site Selection of Aquifer Recharge with Reclaimed Water

The pressure on Egypt’s limited water resources has increased as a result of the country’s growing industrial and agricultural sectors, coupled with climate change impacts and population growth. To overcome the current water stress situation, the utilization of new technologies such as managed aquifer recharge (MAR) is thought to be key for expanding the use of non-conventional water resources and providing necessary water supplies. Managed aquifer recharge can boost groundwater recharge and promote greater water accessibility. Suitability maps for MAR are widely offered as a tool to aid in decision-making in the context of balancing water demand and supply. Conducting a sensitivity analysis to validate suitability mapping can enhance the understanding of the results and pinpoint the influencing factors. The West Delta region was chosen as a case study given the existence of two MAR sites to examine the suitability of implementing MAR projects with reclaimed water. In this work, a spatially explicit sensitivity analysis is performed on a newly developed framework for MAR suitability maps that use multi-criteria decision analysis (MCDA) to determine suitable locations for MAR implementation, using spreading methods techniques. The performed sensitivity analysis uses spatial visualization to examine the effect of various weighted criteria on the final outputs and identifies criteria that are especially sensitive to weight changes. The results of the sensitivity analysis indicate that the applied MCDA framework for the suitability mapping in West Delta produced robust results in terms of the most suitable sites for MAR. The obtained results also indicate the possibility of the use of the suggested framework for arid environments with comparable data availability. Moreover, the results emphasize the possible use of suitability maps in sustainable groundwater management plans to support the actual implementation of MAR projects in the West Delta.

Mesocosm Evaluation of the Safety of the Use of Reclaimed Water Regarding Emerging Pollutants in Murcia, Spain

The increasing shortage of conventional water for crop irrigation in arid and semiarid regions is encouraging the use of nonconventional water resources. Nevertheless, concern about the presence and possible negative effects of emerging contaminants in reclaimed water can cause individuals to avoid using these water sources. To clarify the guarantees that reclaimed water offers, a mesocosm study was carried out. Lettuce plants were cultivated in pots watered with three different types of water (distilled, reclaimed, and spiked with contaminants of emerging concern). The results showed low concentrations of contaminants in the leachates and plant tissues when the reclaimed water was used. However, their concentrations were high when the pots were watered with the spiked water; this was mainly true for carbamazepine, which reached a maximum of 2982 ng L−1 in the leachates and 45.2 ng g−1 in the plant roots. In the lettuce watered with the spiked water, carbamazepine was found in the edible part at very low concentrations that did not imply any human risk. Finally, an acute toxicity test was performed on the leachates, which were found to be only slightly toxic in the spiked water. This work indicates that with the current technical improvements in active sludge water treatment, reclaimed water can be used for irrigation without the risk of contamination by contaminants of emerging concern.

Costs-benefit Analysis for the use of Shallow Groundwater as non-conventional Water Resource

Encouraging the implementation of non-conventional water resources (NCWR) is a fundamental strategy to face the future challenges due to urban population growth and resource scarcity. The implementation of a systematic process of Cost Benefit Analysis (CBA) offers reliable economic indicators to support decision makers in taking actions shifting towards NCWR. While infrastructure costs are directly estimated, while the benefits depend upon the considered stakeholders and require a tough estimation of the achieved ecosystem services. This research provides a framework for CBA analysis adopting NCWR at municipal level. The framework has been then applied to two case studies in Milan focused on the exploitation of shallow groundwater, where the obtained economic indicators has stressed out the importance of considering a complete benefits analysis that could support incentive policies on shifting part of the financial benefits to direct users leading to benefits for the whole community.

Floods and Adaptation to Climate Change in Tourist Areas: Management Experiences on the Coast of the Province of Alicante (Spain)

One of the principal challenges for cities on the Mediterranean coast is the management of urban runoff after episodes of intense rainfall. This problem is aggravated by the effects of climate change, with the increase in the frequency and intensity of extreme weather phenomena in this region. In light of this situation, the local governments, in collaboration with the concessionaire companies providing supply and sewage services, are committed to adopting measures aimed at a more efficient management of non-conventional water resources. Examples of good practice for reducing urban flood risk and adapting to climate change are those actions developed in the tourist municipalities of Alicante, Torrevieja, and Benidorm, where measures have been implemented or have been planned and integrated with green spaces, with a commitment to sustainability, such as sustainable urban drainage systems (SUDS) or Nature-Based Solutions (NBSs). This study analyses these case studies, based on a detailed review of the technical projects that contemplate each of the actions. Furthermore, several field trips were made with technical personnel who are familiar with the measures adopted. The results show that the implementation of these systems contributes to advancing the reduction of urban flood risk and the adaptation to climate change, creating more resilient and safer urban spaces for the citizens residing in them.