Search Results (37)

Enhancing the seismic resilience of urban water distribution networks (WDNs) requires the improvement of both earthquake resistance and rapid recovery capabilities within the system. This paper proposes a multi-objective method to enhance the seismic resilience of the WDNs, focusing on system restoration capabilities while comprehensively considering the hydraulic recovery index, maintenance time, and maintenance cost. The method utilizes a random simulation approach to generate various damage scenarios for the WDN, considering pipe leakage, pipe bursts, and variations in node flow resulting from changes in water pressure. It characterizes the functions of the WDN through hydraulic service satisfaction and quantifies system resilience using a performance response function. Additionally, it determines the optimal dispatch strategy for emergency repair teams and the optimal emergency repair sequence for earthquake-damaged networks using a genetic algorithm. Furthermore, a comprehensive computational platform has been developed to systematically analyze and optimize seismic resilience strategies for WDNs. The feasibility of the proposed method is demonstrated through an example involving the WDN in Xi’an City. The results indicate that the single-objective seismic resilience improvement method based on the hydraulic recovery index is the most effective for enhancing the seismic resilience of the WDN. In contrast, the multi-objective method proposed in this article reduces repair time by 17.9% and repair costs by 3.4%, while only resulting in a 0.2% decrease in the seismic resilience of the WDN. This method demonstrates the most favorable comprehensive restoration effect, and the success of our method in achieving a symmetrically balanced restoration outcome demonstrates its value. The proposed methodology and software can provide both theoretical frameworks and technical support for urban WDN administrators. Full article

This study, taking Anhui Province as a case study, systematically evaluated the spatiotemporal differentiation characteristics of six ecosystem services (biodiversity maintenance, water yield, carbon fixation, vegetation net primary productivity (NPP), soil retention, and crop production) from 2000 to 2020 through the integration of multi-stakeholder decision-making preferences and the Marxan model. Four conservation scenarios (ecological security priority, social benefit orientation, minimum cost constraint, and balance synergy) were established to explore the spatial optimization pathways of ecological protection zones under differentiated policy objectives. The findings indicated that: (1) The ecosystem services in Anhui Province exhibited a “low north and high south” spatial gradient, with significant synergies observed in natural ecosystem services in the southern Anhui mountainous areas, while the northern Anhui agricultural areas were subjected to significant trade-offs due to intensive development. (2) High service provision in the southern Anhui mountainous areas was maintained by topographic barriers and forest protection policies (significant NPP improvement zones accounted for 50.125%), whereas soil–water services degradation in the northern Anhui plains was caused by agricultural intensification and groundwater overexploitation (slight soil retention degradation covered 24.505%, and water yield degradation areas reached 29.766%). Urbanization demonstrated a double-edged sword effect—the expansion of the Hefei metropolitan area triggered suburban biodiversity degradation (significant degradation patches occupied 0.0758%), while ecological restoration projects promoted mountain NPP growth, highlighting the necessity of synergizing natural recovery and artificial interventions. (3) Multi-scenario planning revealed that the spatial congruence between the ecological security priority scenario and traditional ecological protection redlines reached 46.57%, whereas the social benefit scenario achieved only 12.13%, exposing the inadequate responsiveness of the current conservation framework to service demands in densely populated areas. This research validated the technical superiority of multi-objective systematic planning in reconciling ecological protection and development conflicts, providing scientific support for optimizing ecological security patterns in the Yangtze River Delta region. Full article

Despite the billions of euros used as subsidies over recent decades, Portugal’s water sector continues to struggle, being characterized by significant inefficiencies and differences between high- and low-performing water and sanitation services (WSSs). Current subsidy policies lack transparency and are not linked to performance results, undermining efforts to promote efficiency and sustainability in both environmental and financial dimensions. To address these issues, this article highlights relevant aspects to be taken into account in the redefinition of funding allocation in the Portuguese WSS sector. By implementing performance-based criteria for subsidy allocation and prioritization, regardless of the identity of beneficiaries or providers, we aim to instigate accountability and efficiency in this process. The analysis draws on empirical data to highlight the shortcomings of existing practices and demonstrates the potential benefits of adopting the “user-pays” principle. This principle is able to improve the definition of tariffs aiming for full cost recovery, while still providing for disadvantaged and vulnerable customers through social tariffs or assistance programs. Key findings indicate that coordinated efforts among government agencies, regulators, public and private utilities, and municipalities are essential to develop and promote effective financing strategies. This stakeholder’s cooperation is essential for managing the urban water cycle sustainably and addressing the sector’s long-term challenges. This research implies that a strategic shift in subsidy allocation is required, to develop accountability, efficiency, and equity in the WSS sector. The allocation of financial resources must be better justified to enhance overall performance in the sector. Full article

Concrete self-healing technology is an effective method for autonomously repairing cracks, which can reduce the maintenance costs of concrete components and prolong their service life. This study investigates the mechanical properties and self-healing abilities of mortar with internally mixed superabsorbent polymers (SAPs) and crystalline admixtures (CAs). The compressive strength and recovery rate of the specimens were evaluated, and the self-healing performance of concrete specimens was assessed through water absorption tests and optical microscopy observation of healed cracks. Microscopic analysis of the crack fillings was conducted using SEM-EDS and XRD tests, revealing the mechanism of the synergistic effect of SAPs and CAs on self-healing. The results indicate that the physical filling effect of SAPs’ water absorption and expansion almost completes the healing action before the 7-day healing age, with a weakened healing ability after this age. The chemical action of CA activation continues to heal cracks up to the 90-day healing age. When SAPs and CAs are incorporated together into the concrete matrix, the mortar specimens exhibit the best healing ability before the 7-day healing age. As water is released from the SAPs, the ongoing activation reaction of CAs shows the most effective healing result at the 90-day age. SEM-EDS analysis confirmed that the addition of CAs increases the Ca/Si ratio of calcium silicate hydrated, transforming it from an amorphous cluster structure to a needle-like structure. Furthermore, the internal curing effect of SAPs promotes the activation reaction of CAs, resulting in a greater quantity of more densely structured calcium silicate hydrated. Full article

The growing population, intensified anthropogenic pressures and climate variability have increased the demands on available water resources, and water reuse has become a high priority, particularly in areas of the world suffering from water stress. The main objectives of this review paper are to consider and identify the potential opportunities and challenges in the implementation of water reuse schemes worldwide by considering and analyzing different fields of interest in water reuse, the current and future global drivers of water reuse policies, the existing advances in treatment and reuse technologies promising elimination of environmental footprint and human health risk, an analysis of the trends in potable and non-potable reuse, and the development of quality criteria and issues related to transition circular economy. Moreover, the major knowledge gaps in critical issues on different domains of water reuse schemes are discussed. For this study, a thorough analysis of the current literature was conducted, using research and review articles, technical reports, specific national (and EU) proposals, guidance documents, and legislative initiatives and actions, as well as any validly disseminated findings by scientists around the world in the wider scientific area of (alternative) water resources, water supply, water management, sustainable development, and protection of public health. Water reuse practices are expected to increase in the future, mainly in developed countries and climate-vulnerable areas of the planet. Current advances in wastewater treatment and water reuse technologies can provide the opportunity for the foul exploitation of alternative water resources, increasing the potential of potable and non-potable water reuse systems worldwide, relying on pollutant/contaminant elimination, and improving economic and energy performances. Moreover, paradigmatic and technological switches based on an improved understanding of the relationships between the water cycle and the Water–Energy–Food (WEF) Nexus will increase the perspective of water reuse schemes. The benefits of the recovery of nutrients through sewage wastewater treatment are also highlighted, arising from reduced costs associated with their sheer removal and the supplement of fertilizers to the WEF Nexus. On the other hand, reduced nutrient removal may promote agricultural or landscape reuse practices, contributing to less energy consumption and reducing GHGs emissions. Regarding the management of water use schemes, a holistic approach (integrated management) is proposed, incorporating regulatory actions, actions increasing public awareness, interconnection among actors/stakeholders, and efficient control and monitoring. The establishment of quality criteria is paramount to preventing undesirable impacts on humans and the environment. The study considers the “one water” concept, which means equal water quality criteria independent of the origin of water, and instead differentiates among different types of water reuse as a means to facilitate implementation and management of potable and non-potable water reuse. Finally, it highlights the need to understand the impacts of water reuse systems on ecosystem services (ESs) and the consequences of achieving the global sustainable development goals (SDGs). Full article

Water access is recognized as a human right by the United Nations since 2010. However, even when piped water is available, the economic crisis has limited poorer households to afford those services on a regular basis. Users become debtors as utilities face growing service costs and shrinking national public funds, pushing tariffs as the main source of revenue for cost recovery. The COVID-19 pandemic lit up affordability issues and health consequences of disconnection policies. Countries worldwide banned water shutoffs during the last year, ensuring water and wastewater service access for all citizens. Although disconnection is a way to reduce the number of debtors, it is, at the same time, considered a threat to human rights statements. This study gathered information on water subsidies, disconnection and vital flow policies applied among several medium- and high-income countries, in order to analyze how utilities have dealt with default rates and if there is any difference between the approaches between medium- and high-income countries. Through case studies, this paper also aims to inspire other practitioners facing the same issues. Based on the eleven case studies presented here, we concluded that high-income countries use assistance programs over water disconnection policies when compared to medium-income ones. Water shutoffs are explicitly forbidden in the United Kingdom, Australia, and France. Although a humane alternative, water flow restrictors have limited application, especially considering the technical issues involved. Full article

Although healthy ecosystems are vital to sustaining human society, the Brazilian Cerrado and Atlantic Forest biomes have suffered from disorderly human development and the intense use of natural resources. Thus, cost-effective studies are needed to develop tools to assess environmental conservation and the integrity of water courses to inform decisions for ensuring their recovery where ecosystem maintenance is deficient. This study sought to develop a methodology in which the Watershed Habitat Evaluation and Biotic Integrity Protocol (WHEBIP) and Rapid Assessment Protocol for Habitat Diversity (RAP) could be used in an integrated, adaptive manner to evaluate the Water Ecosystem Integrity (WEI) in courses of rivers and streams in tropical regions of the Brazilian Cerrado–Atlantic Forest interface undergoing intense agricultural exploitation. Accordingly, a spatial assessment using geographic information systems was followed by a field visit to apply the methodology. A preliminary assessment of the soil conditions in the Lobo Reservoir Hydrographic Basin was conducted, identifying stretches of rivers and streams that were suitable for payment for environmental services and for recovery from the impact of anthropic activities. Such activities were present in 50.23% of the basin’s total area, and intensive degradation was found in stretches of the water courses, primarily where the head springs of the Itaqueri River and Lobo Stream, the principal tributaries of the Lobo Reservoir, lie. Native vegetation, Brazilian Cerrado, and reforestation occupy a total of 38.5% of the basin, comprising areas of intense conservation activity by the Brazilian government. Full article

Coffee agroecosystems are considered to have the potential to impact soil hydrological functions positively, such as water infiltration and soil moisture retention; however, it is not clear how hydrodynamic soil properties regenerate after land-use change and what easy to implement and low-cost indicators there are. Common methodologies to assess soil hydraulic properties are time consuming and expensive. Therefore, the development of easy, robust, and inexpensive methodologies is one of the main steps in achieving a comprehensive understanding of the effects of land-use change on soil hydraulic and physical characteristics in time and space. In order to assess soil properties, we investigated the saturated hydraulic conductivity (Ks), and two micro-climatic indicators: soil volumetric water content (VWC) and temperature above (TAL) and below soil cover (TBL) in four land-use types: a thirty-year-old shade-grown coffee (CN); a seven-year-old shade-grown coffee (CP); a one-year-old shade-grown coffee (CC) as well as a non-commercial pasture (PR), in the municipality of Nueva Santa Rosa, Santa Rosa department, Guatemala. Additionally, we conducted a visual soil assessment (VSA) elaborated on by the Catholic Relief Services for coffee soils in Central America. We used the steady version of the simplified method based on a Beerkan Infiltration run (SSBI method) to obtain Ks values after determining historical land use. The SSBI methodology is thought to be a suitable compromise between measurement reliability, applicability, simplicity, and the necessity for repeated sampling in space and time. We also counted the number of shade trees, the canopy cover, vegetation height, soil cover, diameter at breast height, and total number of shade trees. Our findings contend that CN had the highest Ks values, indicating that shade trees have a positive impact on soil hydrological properties in shade-grown coffee agroecosystems. Additionally, CP had the highest VWC content and the greatest effect of leaf litter on soil temperature, indicating a positive impact of leaf litter on microclimatic conditions and soil moisture after seven years of agroforestry coffee plantation. The visual soil assessment suggested that CN had the highest score followed by CP, corroborating the results for Ks and VWC. The selected methodologies proved to be low cost and easy to implement. To counter shortcomings of these methodologies, we recommend monitoring infiltration in tropical land-use systems at regular intervals to better understand the temporal variability of infiltration recovery and ensure robust data in time and space. Full article

Photocatalytic technology is considered as one of the most attractive and promising technologies to directly harvest, convert and store renewable solar energy for generating sustainable and green energy and a broad range of environmental applications. However, the use of a photocatalyst in powder or coating forms restricts its applications due to its disadvantages, such as difficulty in recovery of nano-powder, secondary pollution, low adhesion between photocatalytic coating and substrate material, short service life of photocatalytic film and so on. The investigation and application of photocatalytic glass-ceramics (PGCs) in water purification, bacterial disinfection, self-cleaning and hydrogen evolution have received extensive attention due to their inherent advantages of low cost, easy fabrication, transparency, chemical and mechanical stability. Real-time solutions to energy shortage and environmental pollution faced by the development of human society can be provided by rationally designing the chemical composition and preparation methods of glass ceramics (GCs). This review introduces the concept and crystallization mechanism of PGCs and expounds on the basic mechanism of photocatalysis. Then, the key point difficulties of GCs’ design are discussed, mainly including the methods of obtaining transparency and controlling crystallization technologies. Different modification strategies to achieve better photocatalytic activity are highlighted. Finally, we look forward to further in-depth exploration and research on more efficient PGCs suitable for various applications. Full article

Irrigation contributes to land and ecosystem degradation, especially in intensive farming areas. However, in marginal areas, long-established irrigation systems also supply agroecosystem services. This study aimed to identify and prioritize the external benefits provided by irrigation in extensive grazing farms in an Italian alpine region (Aosta Valley, NW Italy). Three local stakeholder groups (land irrigation consortia members, non-farmer users of the irrigation water service, and non-user citizens) engaged in focus group discussions. The transcriptions were analyzed with an integrated subjective and computer-assisted approach. The main result of the study showed that a convergence of stakeholder opinions led to prioritization of the same four benefits, i.e., hydro-geological and land maintenance, traditional agricultural landscape conservation, biodiversity conservation, and leisure recreational activities provision. Incorporating this information into decision-making processes is relevant in marginal mountain areas, especially in light of the implementation of the water pricing policy laid down in the EU Water Framework Directive. To this end, the economic value of the external benefits should be considered along with the recovery costs for water services. Such information is essential to balance the environmental costs of irrigation and to compare the resource cost of alternative water uses. Full article

Nutrient enrichment of lakes from anthropogenic activities is a significant and increasing issue globally, impairing the health, biodiversity and service provisioning from lakes, with impacts on cultural, recreational, economic and aesthetic values. Internal nutrient loads from lakebed sediment releases are a primary cause of lake eutrophication and have necessitated geoengineering methods to mitigate releases and speed up recovery from eutrophication. Our objective in this review was to evaluate the use of oxygen nanobubbles as a geoengineering technology to remediate low oxygen conditions at the lake sediment/water interface, as a precursor to alleviating eutrophication linked to high internal nutrient loads. Oxygen nanobubbles (NBs) are bubbles < 1000 nm formed at the interface of solid surfaces and aqueous solutions. These bubbles have higher density than water, persist for longer and facilitate greater oxygen solubility than larger bubbles. Methods have been developed to enable NB formation at the surface of carrier materials, which are then used in conjunction with modified local soils (MLSs), to ‘floc, lock and oxygenate’ to strip nutrients from the water column, locking them in lakebed sediments and oxygenating the sediments to prevent re-release of nutrients. Most studies of NBs for lake restoration have thus far only demonstrated their potential for this purpose, using short-term, small-scale core incubations conducted mainly in laboratory settings. Work is required to (1) address scalability, including procurement and cost, (2) extend laboratory incubation studies to large outdoor enclosures and pond/lake trials, (3) examine longevity of the effects in the natural environment, including potential for MLSs to smother benthos and/or have toxic effects, and (4) extend to a range of lake environments and MLS types. Legal, cultural and social acceptance of the technology is another prerequisite of applications in the natural environment and requires individualised analysis. Until these issues are addressed in a systematic way that addresses scalability and recommends suitable carrier materials and MLSs, NBs may continue to remain largely untried as a geoengineering method to address lake eutrophication. Full article

Sustainability and energy prices make the use of energy obtained from renewable sources on an urban scale and for isolated local facilities necessary for municipal authorities. Moreover, when the demand of energy is at night, as for street lighting installations, the use of accumulative systems is necessary, which means a major drawback due to a short lifetime expectancy and high cost. The use of batteries can require more than 70% of the budget of these lighting systems and has a critical impact in the project. The problem to solve is finding different renewable energy sources that can produce energy throughout the day, especially during the night, at the same time at which it is consumed. As one of the competences of municipal authorities is water supply networks, this paper analyzes the use of energy recovery turbines within these installations as an alternative to photovoltaic generators. To study the viability and effectiveness of this alternative, the water flows available in the network of a medium-size municipality were monitored and analyzed in depth to assess the amount of recoverable energy. In addition, an energy recovery turbine (ERT) station was set up, installing a bypass around one of the pressure-reducing valves (PRV) of the installation where energy is dissipated without practical use. The results obtained imply that the system proposed has economical and technical viability, is reliable and guarantees full service in all the seasons’ conditions. Moreover, the needs of the energy storage capacity are much lower (~8%) than with solar panels. Full article

Food service providers like restaurants, cafes, or canteens are of economic importance worldwide, but also contribute to environmental impacts through water and energy consumption. Drain water heat recovery from commercial kitchens, using a heat exchanger, has shown large potential to decarbonise hot water use across food services, but is rarely deployed. This work translates previous findings on the technical feasibility and heat recovery potential for commercial kitchens into a publicly available calculator. It facilitates decision-making towards recovery and reuse of the freely available heat in kitchen drains by estimating both financial costs and payback time, as well as environmental burdens associated with the installation and environmental savings from avoided energy consumption. Environmental burdens and savings include, but are not limited to, carbon emissions. Further, the tool highlights key aspects of the technical implementation to understand installation requirements. The tool is freely available and could contribute to the uptake of heat recovery in the food service sector, ideally in conjunction with policy support through financial incentives or subsidies. Full article

Most renewable energy (RE) studies focus on technology readiness, environmental benefits and/or cost savings. The market permeation, viability and adoption of RE technologies such as micro hydropower (MHP), however, require the alignment of other interrelated factors, such as the socio-technical, institutional and political dimensions. This is particularly the case where the energy recovery potential in decentralised water networks is being explored as part of a wholesome sustainability strategy by and for individual and communal prosumers. This study employs a socio-technical approach to understand factors that influence the perceived viability and adoption of MHP in group water-energy schemes. Methods included a progressive literature review to formulate a conceptual framework for the implementation of MHP systems. The framework was validated using survey data from representative stakeholders from groups schemes in Ireland and Spain. These stakeholders were sampled and surveyed at the stage of considering the adoption of MHP in their water networks. The findings highlight the push–pull factors and discusses the opportunities and barriers to the adoption of MHP systems. It confirms that the market, institutional and policy context, cost and financial benefits, social support and collaborative services combine to influence the adoption of MHP technology. Thus, a framework for evaluating the socio-technical viability of MHP systems based on these more realistic integrated, multi-dimensional criteria is proposed. Full article

The Gravity Recovery and Climate Experiment (GRACE) satellite provides time-varying gravity field models that can detect total water storage change (TWSC) from April 2002 to June 2017, and its second-generation satellite, GRACE Follow-On (GRACE-FO), provides models from June 2018, so there is a one year gap. Swarm satellites are equipped with Global Positioning System (GPS) receivers, which can be used to recover the Earth’s time-varying gravitational field. Swarm’s time-varying gravitational field models (from December 2013 to June 2018) were solved by the International Combination Service for Time-variable Gravity Field Solutions (COST-G) and the Astronomical Institute of the Czech Academy of Sciences (ASI). On a timely scale, Swarm has the potential to fill the gap between the two generations of GRACE satellites. In this paper, using 26 global watersheds as the study area, first, we explored the optimal data processing strategy for Swarm and then obtained the Swarm-TWSC of each watershed based on the optimal results. Second, we evaluated Swarm’s accuracy in detecting regional water storage variations, analyzed the reasons for its superior and inferior performance in different regions, and systematically explored its potential in detecting terrestrial water storage changes in land areas. Finally, we constructed the time series of terrestrial water storage changes from 2002 to 2019 by combining GRACE, Swarm, and GRACE-FO for the Amazon, Volga, and Zambezi Basins. The results show that the optimal data processing strategy of Swarm is different from that of GRACE. The optimal results of Swarm-TWSC were explored in 26 watersheds worldwide; its accuracy is related to the area size, runoff volume, total annual mass change, and instantaneous mass change of the watershed itself, among which the latter is the main factor affecting Swarm-TWSC. Knowledge of the Swarm-TWSC of 26 basins constructed in this paper is important to study long-term water storage changes in basins. Full article