Freshwater Demand Research Articles

Ground-Runoff Harvesting to Increase Water Availability in Isolated Households on Hilly Mediterranean Islands: A Case Study in a Micro-Catchment of Ibiza (Spain)

Mediterranean islands suffer from a lack of freshwater due to persistent and recursive droughts, limited groundwater availability and mass tourism. In Ibiza (Spain), private estates disconnected from the water distribution network consume about 21% of the total freshwater demand on the island. We conducted a study to evaluate the potential of ground-runoff harvesting (GRH) as a sustainable and inexpensive solution to increase freshwater availability in isolated households in Ibiza. The study involved an innovative modular tank of 40 m3 buried in the garden of a private property. The tank intercepted runoff forming in a 12,300 m2 hilly micro-catchment. We found that an extreme rainfall event with an intensity of 65 mm/h was able to create sufficient runoff to fill up the tank in one hour. A curve-number-based rainfall-runoff model was used to simulate the experimental results and to obtain a first-cut estimation of the potential of GRH at the scale of the island. The analysis indicates that, if installed in all forest areas in Ibiza with a similar slope to the study area, a volume of 1.31×106 m3 of freshwater could be harvested per year on the island just from extreme precipitation events. Such a volume of water is equivalent to about 5% of the island’s total freshwater budget. The study concludes that GRH is a highly valuable, yet still unexploited opportunity to save large freshwater volumes in dry-climate areas like Ibiza. GRH should be promoted across Mediterranean islands, and it can be easily incorporated within local water regulations.

MXene‐Based Capacitive Deionization–Strong Competitor Among Faradaic Electrode Systems: Current Status and Future Perspectives

AbstractCapacitive deionization (CDI) of brackish water is emerging as a sustainable and energy efficient desalination processes to mitigate the excessive demand of freshwater. Despite that the porous carbon is prime choice in the conventional CDI; its electrostatic interaction‐based limited salt adsorption capacity (SAC, up to 25 mg g−1) has driven the research interest to explore various Faradaic electrodes for attaining maximum SAC (>100 mg g−1) in supplementation with the other desalination metrics. MXene is one of the newly discovered intercalation‐type pseudocapacitive nanostructures, which promised an excellent desalination performance due to its intriguing properties, such as tuneable interlayer spacing, high electrical conductivity, hydrophilicity, and structural integrity. Furthermore, its compositing/heterostructuring with other electro‐active components significantly improves the desalination activity. This article provides a systematic overview of the MXene‐based electrodes utilized in CDI along with the one‐to‐one comparison with other Faradaic systems. Materials design, structure, cell architecture, desalination metrics‐based performance evaluation, and underlying driving forces behind the salty ions removal activity are the main emphasis of discussion to realize MXene‐based efficient CDI desalination. Lastly, the key issues and perspectives of MXene‐based electrode systems are put forward towards new developments and real time implication.

Produced-Water Desalination Approach Uses Renewable Thermal Energy

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 211175, “An Innovative Method of Water Management by Desalinating Produced Water Using Thermal Renewable Energy,” by Sharifa M. Al-Ruheili, Felix Tiefenbacher, and Khansaa H. Almahrami, ARA Petroleum Exploration and Production, et al. The paper has not been peer reviewed. _ The operator is adopting a method to manage high-salinity produced water in an environmentally sustainable way by extracting potable water from produced water and reducing discharge water volume by at least 50%. For desalination of the produced water, a combination of forward and direct osmosis technology is used. This process is driven mostly by thermal energy, which is provided to thermal collectors that are 100% solar. This technology uses renewable energy and will have no carbon footprint. Technology Description The technology involves concentrated solar thermal (CST) power plants that provide 100% renewable water desalination. Forward osmosis (FO) and direct osmosis (DO) can desalinate highly saline and polluted water, such as produced water, mainly with solar thermal energy. A pneumatic solar thermal plant consisting of two HELIOtube collectors, each 121 m long, provides the thermal energy for the desalination process. The plant includes a mirror technology based on CST, a cost-effective heat-transfer system using pressurized water as heat transfer fluid (HTF), and a low-maintenance thermal energy storage (TES) system allowing nighttime operations of 35 m3 volume with an operating temperature of 180°C using a pressurized water tank at 10-bar operating pressure. The desalination system will contain a pretreatment unit for the produced water and a desalination (FO) and brine-concentration (DO) unit. The unit will be integrated with thermal power to operate the desalination plant. In addition, a fully automated control system with a live backup will be installed. The system is classified as having low maintenance and cleaning costs because of its encapsulation features, rotatability of 300°, and convex shape. Fig. 1 of the complete paper shows the planned plant layout. The desalination plant will feature two outputs: fresh water of potable quality and brine. The fresh water will be used to serve the company’s freshwater demand, with excess water used for agricultural purposes or mixed with water in an injector well to improve injectivity. The other output, the highly concentrated brine (20% salt), will be collected in the existing evaporation pond where two main research and development studies are ongoing, one related to mineral extractions and the second related to salt monetization (using salt as a drilling additive).

On the application of Transient Electromagnetics (TEM) and DC-resistivity methods for groundwater level detection in the Cipatat karst area

Due to mountainous morphology, meeting the freshwater demand for daily consumption in some villages in the Citatah karst area is problematic. Some water springs exist in some parts of the valley and slopes. The water flows through pipes connecting people’s houses by pumping it using electricity. To know the potential of the groundwater in the area, we conducted geophysical surveys in a test area close to known dig wells. These are Transient Electromagnetic (TEM) and DC-resistivity methods. TEM data were collected using an in–loop transmitter-receiver configuration with Temfast 48 devices with 5 m × 5 m and 10 m × 10 m wire loops. We acquired resistivity data using a 4-point light 10w IP device, producing resistivity and chargeability data. In this preliminary result, we show only resistivity distribution. We validated the processed TEM and resistivity data with the data from seven dig wells. Our results deliver good results. The resistivity data reveals low resistivity anomalies ranging from 26.5 Ωm to 58.5 Ωm. This low resistivity zone lies at 0.6 m – 1.45 m depth associated with groundwater level.

Venturi nozzles for desalination brine discharges

Seawater desalination is a reliable way to confront the growing challenges of freshwater demands in the world. Brine is the primary by-product of this process and needs to be carefully managed and discharged back into the sea. In coastal desalination plants, the use of submerged outfall as a pipeline laying on the ocean floor is a popular strategy to minimize the environmental impacts of brine discharge. The Venturi nozzle has been proposed as a more efficient method for dispersing brine into the ocean. However, it requires a high exit velocity, which poses limitations for steep nozzle angles in shallow waters. This study aims to investigate the benefits of a lower range of exit velocities in the Venturi nozzles. The 60° inclined dense jet from a Venturi nozzle was explored, numerically and experimentally, and the results were compared to those of a simple dense jet. Comparisons showed that the Venturi nozzle decreases the flow path and diminishes flow dilution at the critical points. However, this reduction can be compensated by increasing the discharge Froude number to reach the same trajectory as a simple jet. It is important to note that this compensation is intricately linked to the discharge velocity, and it makes the use of Venturi nozzles for brine discharge a challenging proposition in both deep and shallow waters.

Operation of interconnected power and freshwater networks

As freshwater demand continues to rise and conventional freshwater resources decline, the interaction between the freshwater and power sectors is becoming increasingly relevant. Coordinating both systems entail minimizing the operation costs of the power and freshwater system while supplying the demands of electricity and freshwater and complying with operational constraints. This is particularly relevant in Middle Eastern regions, which have limited availability of freshwater resources. Careful coordination of electricity generation and freshwater production is beneficial for both the power and the freshwater systems. For example, producing excess freshwater at hours of low electricity production cost and storing it for usage at hours of high electricity production cost is economically advantageous. We use detailed models for the operation of the power and freshwater systems. That is, the power system operation is represented through a network-constrained unit commitment model, while the freshwater system model includes nonlinear representations of the freshwater production and transportation. The resulting problem is computationally intractable for large-scale systems. To achieve tractability, nonlinearities in the freshwater model are linearized. The final model is a tractable mixed-integer linear optimization problem that is solved using a state-of-the-art branch-and-cut solver. Simulation results demonstrate that a coordinated scheduling results in lower cost and lower peak as compared with uncoordinated scheduling.

An Overview of Wastewater Treatment and Reuse in The Gulf Cooperation Council Countries

The human population generates a substantial amount of waste, and if it is discarded without any treatment it can lead to environmental degradation. This is commonly executed by discharging substantial amount of untreated wastewater in the waterways. Wastewater can be generated from numerous locations but for this review the principal areas concerned are municipalities and industries. The focus of the current study relies on performing a thorough review on expressing the benefits of treating wastewater, assessing Gulf Cooperation Council (GCC) reuse regulations associated with wastewater reuse, identifying different wastewater treatment technologies, and evaluating previous research implemented on this field across the GCC region. Various case studies about treatment technologies and reuse regulations are analyzed in this review for each country within the GCC. The findings show that treating wastewater holds many benefits such as reducing environmental pollution and can aid in helping nations with limited access to fresh water to meet their demand. The technologies for treating wastewater are discussed, such as: conventional filtration, chemical, biological treatment, and different membrane technologies. The review conveys that although treating water has many benefits, there are still many challenges associated with the cost, public perception, and management policies that need to be resolved. To improve wastewater treatment policies effective management can show greater potential for mitigating the freshwater shortage in the GCC countries. Also, since each GCC country has different policies regarding wastewater management, more research should be conducted in the future to adapt as the GCC territory is competing to produce new wastewater treatment plants to accommodate their growing demand for fresh water.

Energy management and sizing of a stand-alone hybrid renewable energy system for community electricity, fresh water, and cooking gas demands of a remote island

Research into the off-grid hybrid energy system to provide reliable electricity to a remote community has extensively been done. However, simultaneous meeting electric, freshwater, and gas demands from the off-grid hybrid energy sources are very scarce in literature. Power- to-X (PtX) is gaining attention in recent days in the energy transition scenarios to generate green hydrogen, the primary product of the process as an energy carrier, which is deemed to replace conventional fuels to reach absolute carbon neutrality. In this study, renewable–based hybrid energy is developed to simultaneously meet the electricity, freshwater, and gas (cooking gas via methanation process) demands for a remote Island in Bangladesh. In this process, an energy management strategy has been developed to use the excess energy to generate both freshwater and the hydrogen, where hydrogen is then converted to natural gas via methanation process. The PV, wind turbine, diesel generator, battery, and fuel cell have been optimized using non-dominating sorting algorithm-II (NSGA-II) to offer reliable, cost-effective solutions of electricity, freshwater, and cooking gas for the end users. Results reported that the PV/WT/DG/Batt configuration has been found the most economic configuration with the lowest COE (0.1724 $/kWh) which is 9 % lower than PV/WT/Batt configuration which has the second lowest COE. The cost of water (COW) and cost of gas (COG) of the PV/WT/DG/Batt system are also the lowest among all the four configurations and have been found 1.185 $/m3 and 3.978 $/m3, respectively.

Urbanization shifts freshwater service flows in the highly urbanized watersheds of Dongjiang River, China

Freshwater ecosystem services supply and demand are important for achieving Sustainable Development Goal 6 of clean water. Urbanization has significantly impacted the supply, demand, and flow of freshwater ecosystem services due to various human activities. However, the changes in freshwater ecosystem service flow (FESF) under the influence of urbanization were still unclear. This study examines the highly urbanized Dongjiang River as an example and maps the supply-flow-demand network of freshwater services based on social-ecological network analysis. The results indicate that freshwater supply has increased by 0.21 billion m3 per year, while there is a decreasing trend of 0.17 billion m3 per year in demand. The FESF approach reveals that 42%–60% of imbalanced sub-watersheds rely on artificial water diversion projects to alleviate water deficits under dynamic flow conditions. Approximately 15.6% of the region experiences water insecurity, driven by urbanization-induced demand for water diversion. This increased demand puts stress on downstream sub-watershed water supply and elevates the risk of flow reduction in the main stream. The study highlights the need for sustainable water management strategies to ensure freshwater security in large river basins within urbanized areas worldwide and to address the challenges posed by uncertain urban expansion.

Can International Freshwater Trade Contribute to the SDG 6

Freshwater is fundamental for all aspects of human well-being and sustainable development. The supply of freshwater resource largely depends on the natural water cycle, leading to extremely unequal distribution over the world. This uneven distribution and increasing freshwater demand results in spatial and temporal physical freshwater shortage. By discussing the limitations of desalination techniques and the shortcomings of existing pathways for freshwater transfer including water transfer projects, bottled water market, and virtual water trade, we suggest that international freshwater trade as an additional pathway is necessary. The analysis of the cost structure of freshwater production and transportation and the hypothetical examples between potential exporting and importing countries show the feasibility of international freshwater trade. The establishment of a global freshwater market is confronted with six challenges, namely, natural sustainability, ecological safety, opinions of stakeholders, market access mechanism, pricing mechanism, and infrastructure system. We conclude that a global freshwater market is expected to make contributions to achieving SDG 6 by mitigating spatial and temporal freshwater scarcity and by resolving transboundary freshwater conflicts and managing local freshwater consumptions.

Modelling of a hybrid wind power generator–water distillation system using a Venturi tunnel

Abstract This study presents the development of a novel hybrid wind power generator–water distillation system with the objective of providing sustainable solutions for impoverished isolated communities facing limited resources. The advantage of the proposed system is its ability to operate day and night; therefore, it produces larger quantities of distilled water even on cloudy days with winds. The system comprises a Venturi tunnel integrated with a wind turbine, an attached impure water tank, and a condenser located at the end section. The accelerated airflow at the throat section serves two purposes: water evaporation from the tank and power generation through the wind turbine. The evaporated water is subsequently collected as the airflow decelerates and the pressure decreases along the diverging section. Theoretical and computational modelling is employed to design the system by examining air speed, area ratio, relative humidity, as well as air, and water temperatures. The system exhibits enhanced performance under warm and dry weather conditions, thereby optimizing its performance. Conversely, temperature and relative humidity do not affect power generation; it was increased by higher air speeds and larger area ratios. This data-driven approach ensures optimal design parameters are selected, aligning the system's capabilities with the specific freshwater demand.

Potential of Reducing CO2 Emission Using Parabolic Trough Collector for 13.75MW Desalination Processes

Desalination is an important process in fulfilling the freshwater demands of both the industrial sector and human needs. Typically, thermal desalination processes rely on fossil fuels to minimize production costs. However, using fossil fuel in desalination contributes to releasing CO2 emissions into the atmosphere. Therefore, it is essential to utilize renewable energy sources to mitigate the production of CO2 emissions. To reduce CO2 emissions research has been conducted to explore the potential use of parabolic trough solar collectors in harnessing available solar energy at the power plant site for thermal desalination processes which required 13.75 MW of thermal energy. The study utilized the system advisor model software to assess the collector’s system performance. The research findings indicate that 416 units of parabolic trough solar collectors are required to fulfill the thermal power needs. The presence of these solar collectors has the potential to generate 26.06 GWh of thermal power, thereby reducing coal consumption by 5,740.4 metric tons per year and directly lowering CO2 emissions by 13,892 metric tons per year.

Rates of Groundwater Depletion in India Could Triple by Midcentury

Climate change is contributing to crop stress associated with a growing demand for freshwater.

An integrated framework for examining groundwater vulnerability in the Mekong River Delta region.

The Mekong River provides water, food security, and many other valuable benefits to the more than 60 million Southeast Asian residents living within its basin. However, the Mekong River Basin is increasingly stressed by changes in climate, land cover, and infrastructure. These changes can affect water quantity and quality and exacerbate related hazards such as land subsidence and saltwater intrusion, resulting in multiple compounding risks for neighboring communities. In this study, we demonstrate the connection between climate change, groundwater availability, and social vulnerability by linking the results of a numerical groundwater model to land cover and socioeconomic data at the Cambodia-Vietnam border in the Mekong River Delta region. We simulated changes in groundwater availability across 20 years and identified areas of potential water stress based on domestic and agriculture-related freshwater demands. We then assessed adaptive capacity to understand how communities may be able to respond to this stress to better understand the growing risk of groundwater scarcity driven by climate change and overextraction. This study offers a novel approach for assessing risk of groundwater scarcity by linking the effects of climate change to the socioeconomic context in which they occur. Increasing our understanding of how changes in groundwater availability may affect local populations can help water managers better plan for the future, leading to more resilient communities.

Impact of Acidulants on Salmonella and Escherichia coli O157:H7 in Water Microcosms Containing Organic Matter.

As demands for fresh water become more competitive between the processing plant and other consumers of water such as municipalities, interest has grown in recycling or reusing water for food processing. However, recycling the processing water from a poultry plant, for example, represents challenges due to increased organic loads and the presence of bacterial contaminants including foodborne pathogens. The objective in the current study was to evaluate the inactivation of Salmonella and E. coli O157:H7 using combinations (0.5% and 1%) of sodium bisulfate (SBS) and 1% lactic acid (LA) in water and water with organic matter in the form of horse blood serum (0.3%) with exposure times of 1 min and 5 min. Pathogen reductions after a 5 min exposure time were greater than corresponding reductions after a 1 min exposure time for all acid solutions. The Salmonella counts were significantly reduced (i.e., ≥1 log-unit) in all acid solutions after a 5 min exposure time with the combination of LA + SBS acid solutions being more effective than the corresponding 2% LA solutions. None of the acid solutions were effective in reducing the E. coli O157:H7 after a 1 min exposure time. The 1% LA + 1% SBS solution was the most effective acid solution against both pathogens and was the only acid solution effective in reducing E. coli O157:H7 by at least one log unit after 5 min of exposure.

Benefits and trade-offs of optimizing global land use for food, water, and carbon

Current large-scale patterns of land use reflect history, local traditions, and production costs, much more so than they reflect biophysical potential or global supply and demand for food and freshwater, or-more recently-climate change mitigation. We quantified alternative land-use allocations that consider trade-offs for these demands by combining a dynamic vegetation model and an optimization algorithm to determine Pareto-optimal land-use allocations under changing climate conditions in 2090-2099 and alternatively in 2033-2042. These form the outer bounds of the option space for global land-use transformation. Results show a potential to increase all three indicators (+83% in crop production, +8% in available runoff, and +3% in carbon storage globally) compared to the current land-use configuration, with clear land-use priority areas: Tropical and boreal forests were preserved, crops were produced in temperate regions, and pastures were preferentially allocated in semiarid grasslands and savannas. Transformations toward optimal land-use patterns would imply extensive reconfigurations and changes in land management, but the required annual land-use changes were nevertheless of similar magnitude as those suggested by established land-use change scenarios. The optimization results clearly show that large benefits could be achieved when land use is reconsidered under a "global supply" perspective with a regional focus that differs across the world's regions in order to achieve the supply of key ecosystem services under the emerging global pressures.

Physical, chemical, and biological evaluation of domestic laundry greywater discharges to attract reclamation strategies and reuse applications in urban settings

AbstractDue to increasing freshwater demand and limited availability of resources, conservation and recycling of greywater are getting attention worldwide. Greywater (GW) is considered a potential contender to different types of industrial wastewater in terms of recyclability, toxicity, and reusability. The reuse and treatment methodologies in the case of LGW mainly depend on parameters such as pH, Biochemical oxygen demand (BOD), Chemical oxygen demand (COD), Total dissolved solids (TDS), Total suspended solids (TSS), turbidity, ionic concentration, surfactants, and microbial growth. Available literature suggests that domestic as well as commercial laundries are major contributors to greywater around the globe. This paper presents the results of investigations conducted on the quantity and quality of greywater generated from domestic urban laundries. Various factors were observed that influence the quantity of generated LGW such as family size, type of washing (machine or manual), and composition of LGW influenced by the work profile of family members, etc. The average values of BOD, COD, TSS, TDS, turbidity, Chloride (Cl−), Sulphate (SO42−), Fluoride (F−), Nitrate (NO3−), and anionic surfactants as MBAS (methylene blue active substances) were observed as 265.73 mgL−1, 1754.67 mgL−1, 469.13 mgL−1, 1837.73 mgL−1, 281.8 NTU, 438.6 mgL−1, 87.93 mgL−1, 0.87 mgL−1, 6.83 mgL−1, and 16.45 mgL−1, respectively. The average concentration of Escherichia coli and total coliforms was observed to be 73.4 MPN/100 mL (most probable number per 100 mL) and 386.2 MPN/100 mL, respectively. The high values of selected parameters necessitate the planning of greywater treatment in urban locations for re‐utilization. This study also revealed that a huge amount of freshwater is being converted to greywater by domestic laundries that can be re‐utilized for non‐potable purposes after some treatment.

Novel two-dimensional fused pentagon monolayer as a separation membrane with high desalination properties

The contradiction between supply and demand of freshwater, which has emerged as a global concern, is intensifying as the continued growth of the population on earth, and desalination serves as a tactic to enable open source increment of water resources. Lately, fused pentagon, a hypothetical two-dimensional (2D) carbon allotrope, has focused the attention of researchers due to its extensive five-membered multiple-ring structure and superior properties. However, the potential solute transport mechanism of fused pentagon as a 2D reverse osmosis desalination membrane has not been profoundly elucidated. Here, we combine density functional theory (DFT) and molecular dynamics (MD) to explore the promising feasibility of fused pentagon with abundant penta‑carbon rings for desalination applications, and further analyze the properties superiority of such materials featuring periodic pore structures from the electronic level. The results indicate that the membrane structure constructed by a uniform distribution of enriched pentagonal and dodecagonal pores exhibits exceptional structural stability and satisfactory resistance to salt ion aggregation. Compared with other 2D materials, the 12-membered carbon rings of fused pentagon demonstrate remarkable Na ions adsorption properties (adsorption energy value is −2.049 eV, which is superior than those of the compared 2D materials), with a charge transfer of 0.68 |e| as Na ions across the membrane. Moreover, with the physical pressure increased to 95 MPa, the salt ions rejection rate of fused pentagon could present >92.31 % while preserving superior water molecule penetration, which evidences its favorable desalination properties. Promisingly, fused pentagon manifests intrinsic metallicity, which facilitates self-cleaning upon electrical stimulation. This work clarifies the desalination mechanism of fused pentagon monolayer from a theoretical perspective and contributes to an innovative research concept for the development of carbon-based reverse osmosis materials.

On‐farm response of inbred and hybrid rice cultivars to furrow irrigation

AbstractAlternate wetting and drying (AWD) water management reduces irrigation demand compared to a continuous flood in the drill‐seeded, delayed‐flood rice (Oryza sativa L.) production system, but land preparation is time consuming and labor intensive. This research was conducted to determine whether rice grown in a furrow‐irrigated (ROW), raised seedbed system has similar water requirements and profit expectations to AWD. The effects of growing either inbred or hybrid rice under AWD or furrow irrigation management on water applied, grain yield, and net returns were investigated on paired production fields in the Delta region of Mississippi. For both inbred and hybrid rice lines, water applied averaged 587 and 565 mm, respectively, and did not differ between ROW and AWD production (p > 0.05). Compared to AWD, furrow‐irrigating inbred rice cultivars either maintained or decreased yield 16% (p = 0.0207). Conversely, seeding hybrid rice in ROW systems reduced yield 7% regardless of year (p = 0.0083). For both inbred and hybrid rice cultivars, transitioning from AWD to furrow irrigation decreased the average net returns $9.80 and $124.02 ha−1, respectively, and ranged from +$94.48 to −$281.98 ha−1 over 3 years and three rice prices. Transitioning from AWD to an ROW rice will likely have no effect on freshwater demand but will introduce substantial agronomic and economic risk to the production system.

The fate of bacteria in urban wastewater-irrigated peach tree: a seasonal evaluation from soil to canopy

Irrigation with wastewater can be a solution to preserve and mitigate freshwater demand, in particular during drought periods. Unfortunately, wastewater, although being treated at different levels, could be a carrier of human pathogens (e.g., E. coli) and potentially contaminate crops for human consumptions.This study investigated the seasonal microbiological concentrations, on soil, shoot and fruit tissues of potted peach trees, following two irrigation treatments: freshwater (FW) and secondary urban wastewater without the final disinfection treatment (SW).E. coli was only detected in SW irrigated soil, whereas total coliforms (TC) and total bacteria counts (TBC) were similar in both treatments throughout the season. Endophytic E. coli, Salmonella spp. and TC were not detected in shoot and fruit, but a higher presence of total bacteria (TBC) was observed in SW-irrigated tree compared to FW-irrigated tree. In particular, SW shoots had a higher load compared to fruits, thus showing a potential effect of leaf transpiration, that promoted the transfer of water-borne bacteria from soil to the epigeal part (shoot). The adoption of low-quality SW (even above the microbiological limits of the European Regulation 2020/741 for wastewater re-use in agriculture), when a drip irrigation method is applied, could be a valid alternative to save fresh water without compromising fruit safety.