Water Supply Options Research Articles

Geochemistry of fluoride mobilization in the hard-rock aquifers of central India: Implication for fluoride-safe drinking water supply

Globally, groundwater contamination by fluoride (F−) is a threat to the safe drinking water supply. Nevertheless, our understanding of the geochemical processes of F− mobilization to the groundwater by linking groundwater and aquifer material chemistry is limited. We therefore characterized that in the hard-rock aquifers of Central India, an area that has not been investigated thoroughly despite the known severity of the problem. Exploratory drilling of boreholes (n = 45) and lithostratigraphic modeling identified weathered basalt, vesicular basalt, fractured basalt, sandstone of Lameta, and fractured granite as major aquifers in the study area. The groundwater contamination by F− (concentration >1.5 mg/L) mainly occurred at depths >35 m bgl (at elevations <500 m amsl) of the fractured basalt and fractured granite aquifers, while samples collected from the shallow basalt, sandstone of Lameta, and shallow granite were mostly safe. The F− contamination of groundwater was primarily governed by the chemical evolution of groundwater along the flow path. Solute mass balance in groundwater, in conjunction with the mineralogical characterization of the aquifer materials, suggests that weathering of silicate and carbonate minerals was the dominant form of mineral dissolution in aquifers, which consumed dissolved CO2 along the flow path and resulted in an alkaline pH (>8) in groundwater of the deeper aquifers. The mobilization of F− in the groundwater could primarily be attributed to the ion exchange between OH− in water and structural F− in fluorapatite and F-bearing mica/amphibole. By assessing water quality and aquifer properties, this study suggests that primarily, the sandstone of Lameta and weathered and vesicular basalts can be targeted for F-safe drinking water supply in the study area. Targeting shallow aquifers can be an option for F-safe drinking water supply in other affected areas with similar geological and environmental settings.

Hydro‐modeling the ecosystem impact of wastewater reuse under climate change: A case study in upper Red River basin, Oklahoma

AbstractWater reuse, as a viable option for water supply, must be implemented to minimize the adverse impacts on stream ecosystems that previously received this wastewater effluent. In the State of Oklahoma (OK), USA, local communities have implemented wastewater reuse, and many seek to expand the reuse programs. This study presents a hydro‐modeling analysis based on the Coupled Routing and Excess STorage with VECtor routing (CREST‐VEC) model focusing on the potential ecosystem impacts and societal benefits of wastewater reuse under climate change in the OK portion of the Red River basin. First, a CREST‐VEC model is established for the upper Red River basin and validated against observed streamflow for a 30‐year historical period (1990–2020). Based on the established model, we then assess the sensitivity of ecosystem impact to various climate change scenarios and hypothetical wastewater reuse scenarios. Results show that dominant effects of climate change cause the annual time below environmental flow to increase in the next 30 years, which constrains the room to implement wastewater reuse. However, at sub‐catchment scale, the analyses identify viable locations for allocating wastewater reuse while maintaining ecosystem health. The results also reveal that wastewater reuse brings about the most societal water benefits at minimal cost of ecosystem health under representative concentration pathway (RCP) 2.6 followed by RCP 4.5 and then RCP 8.5. Overall, the study demonstrates capabilities of the hydro‐modeling framework in developing water management plans facing the changing climate.

Evolving Power Factor Correction in Solar Water Pumping Systems through Zeta Converter-Based BLDC Motor Drives

The aim of this paper is to present the design and implementation of a new power conditioning system for a stand-alone solar-powered water pumping system. The system integrates a Brushless DC (BLDC) motor drive with a Power Factor Correction (PFC) Zeta converter to improve energy efficiency and reliability. In order to power BLDC motors for water pumping applications—which are essential for irrigation in isolated locations without access to the grid—the suggested solution attempts to overcome the difficulties related to the direct use of variable solar power. The PFC Zeta converter, which is the system's central component, is made to maximize power extraction from photovoltaic (PV) panels under fluctuating solar irradiation, guarantee high power factor, and reduce harmonic distortion in the electrical grid. A BLDC motor that powers a water pump is efficiently operated by this converter, which also optimizes the DC link voltage. A BLDC motor is especially well-suited for solar-powered applications due to its increased efficiency, dependability, and longer lifespan when compared to traditional induction motors. In order to continuously modify the PV panels' operating point to the maximum power point and maximize the amount of energy they capture, a Maximum Power Point Tracking (MPPT) algorithm is incorporated into the PFC Zeta converter's control strategy. The BLDC motor drive control strategy is carefully designed to guarantee seamless operation and flexibility in response to the fluctuating output from the solar panels, upholding the best possible pumping action in any solar situation. The system's capacity to sustain high efficiency and power factor under a variety of operating circumstances is demonstrated by the experimental findings. When the PFC Zeta converter is used, the solar-powered water pumping system performs much better overall. It shows a notable increase in energy conversion efficiency and lowers total harmonic distortion, which prolongs the pumping system's lifespan. By offering a solid method for raising the effectiveness and dependability of solar-powered water pumping devices, this study advances the sector and holds the possibility of a long-term water supply option for agricultural irrigation in isolated locations. In addition to utilizing renewable solar energy's environmental advantages, the suggested solution tackles the real-world difficulties associated with putting dependable and effective water pumping equipment into off-grid applications.

Design and Implementation of VSI for Solar Water Pump Control

The hardware design, implementation, and digital control method for three-phase AC induction motors based on Field-Oriented Control is discussed in this work Solar-powered water pumping systems have become an practical option for remote irrigation and water supply as renewable energy sources obtain importance. This research enhances such systems performance and dependability by employing a Voltage Source Inverter. In order to optimize the energy transfer to the water pump, the recommended approach uses the Voltage Source Inverter capabilities to transform the variable DC output of the solar panels into a controlled AC supply. The research looks at the choice of power components, control algorithms, and modulation strategies while designing the Voltage Source Inverter. The most suitable modulation strategy is determined after an in-depth review of several different approaches to ensure greater pump performance. This research clarifies on how solar energy conversion and pump control work together to provide sustainable water management in off-grid areas. The research paper "Design and implementation of VSI for Solar Water Pump Control" demonstrates how solar water pumping systems can be optimized using power electronics and control. The project addresses efficiency difficulties and operational differences to create efficient and reliable solar-powered water delivery systems, which support environmental sustainability and rural development. Based on the power of the PV panel, the P&amp;O MPPT method calculates the submersible pump speed. The sensorless speed control method eliminates the requirement for location or speed sensors. The Black Electro-Motives Force calculates speed by estimating the flux angle in the absence of mechanical speed sensors. This method reduces costs and simplifies the system simply by eliminating the requirement for expensive and complicated speed sensors. In order to determine steady-state and dynamic performance in varying insolation conditions, a prototype 5.5 KW inverter was constructed. In conclusion up, the research provided a thorough summary of the hardware and control aspects required for Field-Oriented Control in irrigation systems. The practical outcomes of this study have the potential to spur advancements in irrigation technology and the incorporation of renewable energy, resulting in substantial gains for agricultural productivity and environmental conservation.

Performance test of emitters made from sago midribs in drip irrigation systems

Increasing water use efficiency can be done by using the right irrigation system according to the needs of the plants. One option for efficient water supply is a drip irrigation system. The research aims to obtain conditions with high drip uniformity values. The study was conducted by testing the level of drip uniformity at several water source head pressures conducted with three replications. The indicator of uniformity is based on the coefficient of variance. The test results show that the uniformity value is higher at lower pressures than at higher heads. The uniformity value indicated by the coefficient of friction at high head pressure for the end and the middle section is better than the lower head pressure. The test results for the middle samples with heads of 19 cm, 62 cm, and 113 cm were 44.92, 23.40, and 9.16, respectively, while for the end samples with heads of 30 cm, 66 cm, and 115 cm were 46.39, 14.43 and 10.36, respectively. These values indicate that the relationship between head pressure and coefficient of variation is inversely proportional. The low coefficient of variation means that the water distribution is evenly distributed. So it can be said that using sago midrib material is feasible as an emitter. In addition, the resulting discharge value is small, so it qualifies as an emitter.

Trade-offs between water security and energy use: Lifecycle energy of water supply options in Paju, Korea

Despite net zero movement in Korea's water sector, comprehensive assessments of water-related energy in the region are lacking. Focusing on a water-stressed city with diversified water sourcing, this study evaluated both direct and indirect energy across the entire urban water cycle from abstraction to discharge and reclamation. By considering the energy embodied in pipelines and energy avoided from circular water use, this study compared the energy burdens and benefits of long-range piped water supply options (local supply and inter-basin import) and decentralized circular supply options (rainwater harvesting, greywater reuse, wastewater recycling, water loss reduction, water demand management). The results showed that conventional piped water supply options were still more energy-efficient than decentralized rainwater harvesting, greywater reuse, and some wastewater recycling options. In the case of Paju, advanced treatments required to provide high-quality industrial water made circular water options particularly less energy-efficient. The trade-offs between water security and energy use would be further strengthened in 2040, when the energy needs of the city's water supply increase by 27%. Expansion of the wastewater recycling would add 11% of the energy needs, whereas adoption of water-saving appliances in residential buildings decrease energy needs by 6%. For energy-efficient water management, Paju needs to consider adopting water demand management options, optimizing reclamation technologies and size, and harvesting renewable energy.

Trickling filter systems for sustainable water supply: An evaluation of eco-environmental burdens and greenhouse gas emissions

Despite the global water crisis, the significant potential of trickling filter systems as a crucial auxiliary option for sustainable water supply has received insufficient attention. Therefore, this study presents the first-ever evaluation of the environmental impacts of trickling filter application in wastewater treatment, focusing on eco-environmental burdens. Additionally, the study explores greenhouse gas emissions, energy, and exergy footprints, providing novel insights into the environmental implications of using trickling filters for wastewater treatment. The study's findings indicate that the consumption of heat and electricity in trickling filters has significant environmental impacts, particularly on land use (93.24%), freshwater/marine eutrophication (∼81.98%), and human health (45.36%). The majority of the energy required for trickling filter operation is supplied by fossil fuels (96.02%), resulting in increased greenhouse gas emissions (65.58%). The exergy of trickling filters is highly efficient, accounting for over 95% of the system's energy. Mathematical modeling reveals that anaerobic digestion and secondary clarifier have the highest energy consumption, with contributions of 94.65% and 2.63%, respectively. Construction expenses account for almost 88% of the total cost, with anaerobic digestion (42.15%) and trickling filters (35.39%) being the most costly components. The cost of treating 1 m3 of wastewater is estimated at 0.52 $/m3. Sensitivity analysis demonstrates that electricity (14.66%) and heat (18.65%) significantly impact terrestrial ecotoxicity and land use, respectively. This study presents a framework for future investigations in this field.

The Cost of Alternative Water Supply and Efficiency Options under Uncertainty: An Application of Modern Portfolio Theory and Chebyshev’s Inequality

Sea-level rise, population growth, and changing land-use patterns will further constrain Florida’s already scarce groundwater and surface water supplies in the coming decades. Significant investments in water supply and water demand management are needed to ensure sufficient water availability for human and natural systems. Section 403.928 (1) (b) of the Florida Statutes requires estimating the expenditures needed to meet the future water demand and avoid the adverse effects of competition for water supplies to 2040. This study considers the 2020–2040 planning period and projects (1) future water demand and supplies; and (2) the total expenditures (capital costs) necessary to meet the future water demand in Florida, USA. The uniqueness of this study compared with the previous studies is the introduction of a probabilistic-based approach to quantify the uncertainty of the investment costs to meet future water demand. We compile data from the U.S. Geological Survey, Florida’s Department of Agriculture &amp; Consumer Services, Florida’s Water Management Districts, and the Florida Department of Environmental Protection to project the future water demand and supplies, and the expenditures needed to meet the demand considering uncertainty in the costs of alternative water supply options. The results show that the total annual water demand is projected to increase by 1405 million cubic meters (+15.9%) by 2040, driven primarily by urbanization. Using the median capital costs of alternative water supply projects, cumulative expenditures for the additional water supplies are estimated between USD 1.11–1.87 billion. However, when uncertainty in the project costs is accounted for, the projected expenditure range shifts to USD 1.65 and USD 3.21 billion. In addition, we illustrate how using Modern Portfolio Theory (MPT) can increase the efficacy of investment planning to develop alternative water supply options. The results indicate that using MPT in selecting the share of each project type in developing water supply options can reduce the standard deviation of capital costs per one unit of capacity by 74% compared to the equal share allocation. This study highlights the need for developing more flexible funding strategies on local, regional, and state levels to finance additional water supply infrastructure, and more cost-effective combinations of demand management strategies and alternative water supply options to meet the water needed for the state in the future.

ANALYSIS OF FOOD ADDITIVES IN THE PRODUCTION OF SAUSAGES

Portulaca oleracea L., considered by many a weed, is in fact a plant with multiple food and medicinal values, and with a specific adaptation to stress conditions. Grown in water supply option conditions, the plant has a C4 type metabolism, but in drought conditions, it uses the way of closing the stomata during the day, achieving a CAM type metabolism. The high values ​​of the stomatal conductance recorded in the dark and the high contentof malic acid in the leaves especially in the morning, indicate this adaptation.Plants exposed to water stress also showed higher values ​​of suction force and higher percentages of bound water.

A mixed-integer optimization model for water sector planning and policy making in arid regions

Water sector planning and policy making in arid and semi-arid regions are challenging because many drivers and decision criteria require consideration. In this study, a multi-period mixed-integer linear programming model was developed to integrate and economically evaluate water management options for water supply in arid regions. The applicability of the proposed approach was demonstrated through a case study in the Emirate of Abu Dhabi (EAD), United Arab Emirates. The model was programmed in general algebraic modeling system (GAMS) and solved using the Cplex solver. The model determined the optimal economic and environmental costs, capacity expansion of treatment plants and water transmission systems, and other environmental aspects including the carbon footprint and brine discharge. Results show that the capacity contribution of reverse osmosis for desalination is expected to increase from 5.1% in 2021 to 18.1% in 2050. Based on the model's results for the case study, it was concluded that even with moderate consideration of environmental aspects, desalination plants in the EAD need a major technology transformation from thermal desalination to reverse osmosis The proposed model is proved to be effective for integrated water resources management and infrastructure planning in the EAD, and has the potential for effective application in other arid or semi-arid countries.

The Urban Underground Space beneath the Karst Basin of Guilin, China, Revealed by Ambient Seismic Noise Tomography

Abstract Detection of hidden faults and sedimentary layers in the urban subsoil is significant for the utilization of the underground space, earthquake hazard mitigation, and so forth. Guilin, located in southwest China, is well known for the development of the most typical karst landform in the world and has become an international tourist city that needs scientific planning and knowledge of the urban underground space. After collecting waveform data recorded continuously over a period of about 1.5 months by a dense array of 114 short-period seismic stations installed in and around Guilin, we adopt ambient seismic noise cross-correlation method to extract Rayleigh-wave phase velocity dispersion curves within the period range from 0.5 to 5 s and to obtain a high-resolution S-wave velocity (VS) model of the shallow crust above 9 km using surface-wave tomography. The vertical VS gradient image indicates that the sediment thickness of the Guilin Karst basin is about 1–3 km. Sedimentary layers are relatively thick between Yanshan Mountain and Haiyang Mountain, and along the Yi river valley, where karst groundwater may be abundant and used as an important option for urban water supply. Both the absolute VS velocity image and the relative VS anomaly image clearly reveal the occurrence, location, and deep extension characteristics of major faults. Longsheng–Yongfu, Nanning–Guilin, Yaoshan–Yanshan, Baishi, and Guanyang–Hengyang may be regional deep faults cutting through the upper crust at least. The evolution of the basin is mainly controlled by the steep dipping Longsheng–Yongfu and Baishi faults, and partially controlled by the gently dipping Nanning–Guilin fault in the interior of the basin. The Nanning–Guilin fault is an active and partially buried fault obliquely crossing Guilin city. Urban seismic imaging, such as the new VS tomography presented here, can play an important role in understanding tectonic and tectonic-subsidence earthquake hazards associated with these buried faults.

The long iron line: Water resources development at the United States Military Academy, West Point (1802–1943)

AbstractComprehensive analyses of long‐term region‐specific water resources developments could offer new insights for contemporary water resources planners and decision makers. The objective of this work was to analyze water supply development at the United States Military Academy (USMA) during the 19th and early 20th Centuries through the lens of selected modern water resources planning and management practices. Analysis of water usage, population, and technological growth revealed that changes in technology had a greater influence on total water withdrawals than an increase in population. The USMA water supply system evolved incrementally over much of the 141‐year study period and failure to adequately recognize shortcomings in water supply options resulted in several suboptimal decisions. Communications and enhanced stakeholder participation might have resulted in alternative decisions.

Policy Note: Risk and Uncertainty in the Murray–Darling Basin

Water Economics and PolicyOnline Ready No AccessPolicy Nook — Policy Note: Risk and Uncertainty in the Murray–Darling BasinJohn QuigginJohn QuigginSchool of Economics, Faculty of Business, Economics and Law, The University of Queensland, St. Lucia, Brisbane, QLD 4072, AustraliaE-mail Address: [email protected] Search for more papers by this author https://doi.org/10.1142/S2382624X22710059Cited by:0 PreviousNext AboutSectionsView articleView Full TextPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail View article References Adamson, D, T Mallawaarachchi and J Quiggin [2009] Declining inflows and more frequent droughts in the Murray Darling Basin: climate change, impact and adaption. Australian Journal of Agricultural and Resource Economics, 53, 345–366. Crossref, Google Scholar Bell, S and J Quiggin [2008] The metagovernance of markets: The politics of water management in Australia. Environmental Politics, 17, 712–729. Crossref, Google Scholar Blaug, M [1962] Economic Theory in Retrospect. Cambridge, UK: Cambridge University Press. Google Scholar Borsch, SJ [2004] Environment and population: The collapse of large irrigation systems reconsidered. Comparative Studies in Society and History, 46(3), 451–468. Crossref, Google Scholar Chambers, RG and J Quiggin [2000] Uncertainty, Production, Choice and Agency: The State-Contingent Approach. Cambridge, UK: Cambridge University Press. Google Scholar Council of Australian Governments (2004). Communique 25. June. http://www.pm.gov.au/News/media_releases/media_Release941.html. Google Scholar Ellsberg, D [1961] Risk, ambiguity and the Savage axioms. Quarterly Journal of Economics, 75, 643–669. Crossref, Google Scholar Grant, S, JJ Kline and J Quiggin [2014] A matter of interpretation?: ambiguous contracts and liquidated damages. Games and Economic Behavior, 85, 180–187. Crossref, Google Scholar Grant, S and J Quiggin [2013a] Bounded awareness, heuristics and the Precautionary Principle. Journal of Economic Behavior & Organization, 93, 17–31. Crossref, Google Scholar Grant, S and J Quiggin [2013b] Inductive reasoning about unawareness. Economic Theory, 54, 717–755. Crossref, Google Scholar Jevons, WS [1871] The Theory of Political Economy. London: Macmillan. Google Scholar Knight, F [1921] Risk, Uncertainty and Profit. New York: Houghton Mifflin Company. Google Scholar Quiggin, J [1992] The pioneer’s curse: selection bias and agricultural land degradation. Journal of Risk and Uncertainty, 5, 241–246. Crossref, Google Scholar Randall, A [1981] Property entitlements and pricing policies for a maturing water economy. Australian Journal of Agricultural Economics, 25, 195–220. Crossref, Google Scholar Rumsfeld, D (2002). Transcript of press briefing. February 12. http://www.defense.gov/transcripts/transcript.aspx?transcriptid=2636. Google Scholar Shepherd, T (2022). ‘They’re coming back’: huge flows set to restore life to parched end of Murray-Darling system. The Guardian, November 14. https://www.theguardian.com/australia-news/2022/nov/14/theyre-coming-back-huge-flows-set-to-restore-life-to-parched-end-of-murray-darling-system. Google Scholar Smith, A (1976 [1776]). An Inquiry into the Nature and Causes of the Wealth of Nations, RH CampbellAS SkinnerWB Todd (eds.), Vol. 1. Oxford, UK: Oxford University Press. Google Scholar Willis, E, M Pearce, B Jorgensen and J Martin (2015). Water supply and governance options for outback towns in South Australia. Technical Report Series No. 15/7, Goyder Institute for Water Research, Adelaide, SA. Google Scholar FiguresReferencesRelatedDetails Recommended Online Ready Metrics History Received 10 January 2023 Accepted 11 January 2023 Published: 9 March 2023 PDF download

System Archetypes Underlying Formal-Informal Urban Water Supply Dynamics

Contrary to developed countries, developing countries have been observed to have an increased reliance on a diversity of water supply options to meet their daily demands, where formal supply systems are incapable of fulfilling the daily needs of consumers. In filling a demand-supply gap, informal supply systems are increasingly being associated with issues of long-term sustainability, higher consumer cost, and inequity. Emerging formal-informal dynamics in developing countries require a thorough understanding of complex human-water interactions for policy direction, in order to best support the advancement of urban water sustainability. Accordingly, system archetypes offer a platform to explain the behaviors of complex systems. This paper identifies common system archetypes that define urban waterscapes in the developing world. In this way, Causal Loop Diagrams (CLDs) are used to present relationships and identify common archetypes that define the complexity of urban water supply systems in Hyderabad, Pakistan. These archetypes include ‘fixes that fail’, ‘shifting the burden’, ‘limits to growth/success’ and ‘growth and underinvestment’. These archetypes demonstrate that increases in formal infrastructure capacity and the number of informal suppliers to increase supply reliability are symptomatic solutions, restrained by financial and technical resources, and thus have unintended consequences. Further, a number of policy instruments are discussed as leverage points to achieve financial sustainability of formal systems. This paper emphasizes the need of a policy framework for informal supply system in national and regional water policies to ensure its service reliability as a short to medium term solution.

On the use of a network of trunk pipelines to compensate for the shortage of water resources at the expense of the country’s deep Siberian rivers

The paper discusses topical issues and problems of water supply in scarce and arid regions of the country, including the redistribution of water flows from high-flowing Siberian rivers, which are heavily overflowing during the flood period. In particular, an overview of world experience in solving water supply problems is given, both through desalination of sea water and the use of underground sources, and through the construction of canals and main water pipelines, from futuristic ideas to projects that have already been implemented and have many years of positive operating experience. Special attention is paid to the domestic union experience, plans to turn large rivers to supply the Central Asian republics, the world’s first nuclear plants for desalination of sea water and a main water conduit to supply the Mangyshlak Peninsula. Based on the results of the analysis performed, the main disadvantages, areas, limitations and advantages of various water supply options are identified, which make it possible to draw a conclusion about the possibility of involving unclaimed capacities of main oil and gas pipelines to solve the problems of compensating for the shortage of water resources at the expense of the country's deep Siberian rivers.

A Comparative Study between Managed Aquifer Recharge and Other Community Water Supply Options in Coastal Bangladesh

The acute scarcity of safe water exists in disaster-prone coastal Bangladesh due to the occurrences of brackish or saline and arsenic contaminated groundwater, the salinization of freshwater ponds by inundation during storm surges, and brackish water aquaculture. Millions of people living there mainly depend on pond water and rainwater harvesting system and face severe difficulties to collect freshwater, particularly during the dry season. Therefore, various community water supply technologies, e.g., RO, SIDKO, RPWS, SkyHydrants etc. have been established to meet their daily needs, though the majority of these technologies fall short of the value of time and effort of water collection and sometimes fail to supply water of desired quality. Managed Aquifer Recharge (MAR) technique, also a community water supply system, was designed to provide safe water by creating underground storage of freshwater where ambient groundwater salinity is reduced by infiltrating rooftop or pond water through wells. Understanding the need to sort out the best water supply option, a comparative study has been conducted between MAR and other water supply technologies, and among all of them the MAR has been demonstrated as a low cost, reliable, sustainable, and durable option for providing safe drinking water to the community round the year. The Dhaka University Journal of Earth and Environmental Sciences, Centennial Special Volume June 2022: 157-166

Can Large-Scale Offshore Membrane Desalination Cost-Effectively and Ecologically Address Water Scarcity in the Middle East?

The Middle East will face tremendous water scarcity by 2050, which can only be mitigated by large-scale reverse osmosis seawater desalination. However, the coastal land in the region is rare and costly, so outsourcing the desalination facility to artificial islands could become a realistic scenario. This study investigated the ecological and economic challenges and possible advantages of that water supply option by analysing conceptual alternatives for offshore membrane-based desalination plants of up to 600 MCM/y capacity. Key environmental impacts and mitigation strategies were identified, and a detailed economic analysis was conducted to compare the new approach to state-of-the-art. The economic analysis included calculating the cost of water production (WPC) and discussing the differences between offshore alternatives and a conventional onshore desalination plant. In addition, the study investigated the impact of a changing energy mix and potential carbon tax levels on the WPC until 2050. The results indicate that offshore desalination plants have ecological advantages compared to onshore desalination plants. Furthermore, the construction cost for the artificial islands has a much lower effect on the WPC than energy cost. In contrast, the impact of potential carbon tax levels on the WPC is significant. The specific construction cost ranges between 287 $/m2 and 1507 $/m2 depending on the artificial island type and distance to the shoreline, resulting in a WPC between 0.51 $/m3 and 0.59 $/m3. This work is the first to discuss the environmental and economic effects of locating large-scale seawater desalination plants on artificial islands.

Assessing Groundwater Level Declination in Dhaka City and Identifying Adaptation Options for Sustainable Water Supply

Dhaka city, having a population of about 18 million, depends heavily on groundwater as a source of quality water. However, the city is encountering a rapid depletion of groundwater, and its groundwater-based water supply is at risk of failure. This study was carried out to analyze the groundwater depletion scenarios occurring from 1970 to 2019 in the city and to find suitable options to sustain its water supply. The trends in groundwater levels (GWLs) were quantified by the non-parametric Sen’s slope and their significances were assessed by the modified Mann-Kendall test. Contour maps of GWL were generated to develop the contemporary GWL scenario in the city. Key informant interviews (KIIs) with the Dhaka Water Supply and Sewerage Authority (DWASA) officials, groundwater experts and researchers, in addition to semi-structured interviews with the DWASA consumers were conducted to assess current adaptation practices and to develop potential adaptation options. The effectiveness of the options was assessed by strengths, weaknesses, opportunities and threats (SWOT) analysis and the options were ranked through a normalization process of the weights given by the KIIs for future adaptabilities. The GWLs were found to be decreasing all over the city, varying from 0.6–2.4 m/year. The contour maps demonstrated that the groundwater of the central area had depleted more than the peripheral areas. The locations vulnerable to severe groundwater depletion were identified to be the Khilgaon, Sobujbagh, Motijheel, Dhanmondi, and Sutrapur areas and some parts of the Cantonment and Mirpur areas. Potential options identified were adopting more surface water treatment plants, rainwater harvesting, implementing a block tariff system, reducing non-revenue water, metering water consumption, and promoting public awareness. Spatially-varying adaptation strategies were also suggested for different zones. Some measures adopted by DWASA were not supported by the respondents.

A Hybrid Model for Achieving Universal Safe Drinking Water in the Medium-Sized City of Bangangté (Cameroon)

Providing everyone with safe drinking water is a moral imperative. Yet, sub-Saharan Africa seems unable to achieve “safe drinking water for all” by 2030. This sad situation calls for a closer examination of the water supply options for both rural and urban populations. Commonly, two main aspects are considered: (1) behavioural responses to available or potential water supply options, and (2) socio-economic acceptability. These aspects determine the feasibility and the affordability of bringing safe drinking water as a basic good and human right to everyone. There is a broad consensus that achieving the UN Sustainable Development Goal 6.1 is mostly a financial issue, especially in low-income settings. This communication challenges this view as water is available everywhere and affordable treatment options are well-known. It considers the decentralized water supply model as a reference or standard approach in low-income settings rather than as an alternative. Here, the medium-sized city of Bangangté in the western region of Cameroon is used to demonstrate that universal safe drinking water will soon be possible. In fact, during the colonial period, the residences of the elite and the main institutions, including the administrative quarter, churches, and hospital, have been supplied with clean water from various local sources. All that is needed is to consider everyone as important or accept safe drinking water as human right. First, we present a historical background on water supply in the colonial period up to 1980. Second, the drinking water supply systems and water demand driven by population growth are discussed. Finally, a hybrid model for the achieving of universal access to clean drinking water, and preconditions for its successful implementation, are presented. Overall, this communication calls for a shift from safe drinking water supply approaches dominated by centralized systems, and presents a transferable hybrid model to achieve universal clean drinking water.

Life Cycle Assessment of a seawater reverse osmosis plant powered by a hybrid energy system (fossil fuel and waste to energy)

With the rapid increase of the human population and the concomitant increase in freshwater demand, pressure on this natural resource is increasing. One of the approaches used to overcome water scarcity in several parts of the world is desalination of brackish or seawater. Coupling seawater reverse osmosis (SWRO) with renewable energy (RE) is an active research area and understanding the environmental impact of these integrations using Life Cycle Assessment (LCA) is one of the tools available for the selection of sustainable water supply options for remote communities. This study uses LCA to assess the feasibility of integrating a SWRO with a hybrid energy system to meet the water needs in a remote community. The RE is supplied via electricity generated from biogas produced from the anaerobic digestion (AD) of the organic fraction of municipal solid waste. A 4500 m3/day SWRO plant was designed using WAVE software to satisfy the water demand of a small/medium town in a remote area in Lebanon. The biogas plant sizing was performed using HOMER Pro and different renewable percentages were tested. Biogas characteristics were taken from an existing organic waste AD plant in Lebanon. Based on the available mass of solid waste, the maximum achievable renewable fraction required to operate the SWRO was found to be 60%; the remaining electrical demand was supplied from the grid. The LCA was performed using Simapro Ph.D. version 9 to quantify the environmental impacts of this integration. IMPACT2002+ impact assessment method was used. Results show that using AD to power desalination is viable from an environmental perspective and achieves significant reductions in many categories when compared to conventional fossil fuels. Furthermore, increasing the renewable fraction in the hybrid energy system results in further reduction in the environmental impact. In particular, a 60% reduction in global warming potential was observed compared to conventional fossil fuels. However, for some categories, the impact increases upon increasing renewable fraction particularly for categories related to toxicity, eutrophication and acidification and this is mainly attributed to digestate application on land, highlighting the need for digestate enhancement. Accordingly, the system can be further improved by increasing the amount of waste collected and transformed and adopting a more site-specific design.