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Clarifying the spatiotemporal evolution of sustainable water resources utilization (SWU) and its decoupling effects from economic growth (EG) is essential for the effective management of water ecosystems and sustainable development of basins. However, the traditional Ecological Footprint model limits the ability to compare SWU within a basin, and existing studies need to pay more attention to the importance of water renewability in quantifying SWU. Based on the capital flow and capital stock perspectives, this study constructed an evaluation method for SWU and its decoupling effect from EG by combining the three-dimensional Water Ecological Footprint (WEF), sustainable reclassification, and the Tapio model, and explored different types of SWU enhancement strategies. The results indicate that: (1) From 2010 to 2022, the SWU of the Yellow River Basin (YRB) shows a decreasing and then increasing trend and is generally in water ecological deficit, with a lower SWU in the middle and lower reaches. Overall, the per capita WEF size decreased by 0.73% per year, while the WEF depth increased by 0.26% per year, the pressure and stress on the SWU of the YRB are still significant. (2) Agricultural freshwater use and domestic greywater discharge dominate the WEF of the basin, and the problem of inversion of the water use structure with the industrial structure is evident. (3) Spatial differentiation within the basin is apparent, and SWU shows a spatial distribution of western strength and eastern weakness, with significant consumption of water capital stock due to insufficient water capital flow as the main reason. (4) Topio decoupling analysis shows that WEF and EG are mainly strongly decoupled, with WEF lagging behind EG; the decoupling relationship between SWU and EG evolves from END-SD-WD, reduces the consumption of water capital stock and increasing water capital flow is a reasonable way to realise its stable strong decoupling. This study is essential for SWU studies of large river basins in arid and semi-arid regions. It provides insights into the sustainable management and rational allocation of water resources in the YRB and other similar basins worldwide. • A three-dimensional water ecological footprint model is used to assess the SWU. • The decoupling of WEF size and WEF depth from economic growth is taken into account. • Water stress remains high, and SWU's spatial differentiation is evident. • Inadequate water capital flow leading to consumption of water capital stock is the main reason for the impact on SWU. • Strong decoupling of WEF from economic growth, unstable decoupling of SWU from economic growth. [ABSTRACT FROM AUTHOR]

The presence of trace elements in water for domestic supply or irrigation could pose a significant toxic risk for health, due to direct consumption or bioaccumulation through the ingestion of vegetables irrigated with this water. This paper studies the presence of 41 trace elements plus nitrate and bromate in groundwater, using a multivariate statistical tool based on Principal Component Analysis and a geostatistical Kriging method to map the results. Principal Component Analysis revealed 11 significant principal components, which account for 82% and 81% of the total variance (information) respectively for the two dates analysed. Ordinary Kriging was applied to draw maps of the trace elements and PC scores. This research breaks new ground in terms of the large number of parameters used and in terms of the analysis of spatiotemporal variations in these parameters. The results obtained indicate that PC1 represents the natural quality of the aquifer (geogenic) and that there is little change in the average PC1 value between the two dates studied (June near the peak recharge point and November at the end of summer). Agriculture is the human activity that causes the greatest variations in the quality of the groundwater due to the use of fertilizers and due to watering crops with wastewater (PC7_J and PC5_N, June and November, respectively). Other elements of industrial origin, which are dangerous for human health, such as Pb, Cu and Cd, are grouped together in other principal components. The results show that the decline, or even complete absence, of natural recharge during the summer months leads to an increase in the TEs produced by human activity. This indicates that a temporary reduction in the natural recharge could worsen the quality of water resources. Based on the interpretation of the estimated maps, a synthetic map was created to show the spatial distribution of the areas affected by geogenic and anthropogenic factors. Studies with a global approach like this one are necessary in that the possible sources of pollution that could alter the quality of the groundwater and the amount of trace elements and other potentially harmful substances could increase as time goes by. The main advantage of the methodology proposed here is that it reduces the number of parameters, so simplifying the results. This makes it easier to interpret the results and manage the quality of the water. • PCA and geostatistical methods were used to establish the spatiotemporal variations in 41 trace elements. • A complex spatial relationship between anthropogenic and geogenic activities was reduced to just six categories. • The anthropogenic activity with the greatest impact on groundwater quality is agriculture. • Evaporitic rocks were the main cause of geogenic contamination of the groundwater. [ABSTRACT FROM AUTHOR]

China's growing demand for bulk chemicals and concerns regarding energy security are scaling up coal-to-olefins (CTO) production. Three generations of independent dimethyl ether/methanol-to-olefins technologies have been successively launched with greatly improved production efficiencies. However, to date, widespread concerns regarding the intensive environmental impacts and potential economic risks have not been addressed in the context of this industrialization. Here we show that, through the technological progress from the first to the third generation, life cycle energy consumption, water consumption, and carbon emissions can be reduced to 119.5 GJ/t, 27.6 t/t, and 9.1 t CO 2 -eq/t, respectively, and human health damage, ecosystem quality damage, and resource scarcity impacts can be decreased by 40.5 %, 50.1 %, and 16.4 %, respectively. This is accompanied by an excellent performance in terms of production cost, net present value, and internal return rate at 792.5 USD/t, 173.4 USD/t, and 19.4 %, respectively. Substantial environmental and economic benefits can be gained by coupling renewables in the form of using green hydrogen from solar and wind power to synthesize methanol. Particularly, life cycle carbon emissions and resource scarcity impacts are reduced by 23.4 % and 22.4 %, respectively, exceeding the reduction in technological progress. However, coupling renewables increases the life cycle energy consumption to 154.5 GJ/t, counteracting the benefits of technological progress. Our results highlight the importance of technological progress and coupled renewables for enhancing the sustainability of the CTO industry. • Four coal-to-olefins technology scenarios are compared for nine indicators. • Secondary technological progress largely increases environmental benefits. • Coupling renewables greatly mitigates carbon emissions and resource scarcity. • Coupling renewables rebounds energy use and offsets technological progress. • Technological progress and coupling renewables offer robust economic benefits. [ABSTRACT FROM AUTHOR]

Households play a critical role in reducing greenhouse gas emissions. However, there have been few studies of household conservation from the perspective of the nexus of food, energy, and water (FEW) consumption. This study's objective is to understand the effects of different types of intervention messages for inducing conservation of FEW resources and reducing carbon emissions at the household level in the U.S. Employing a serious-gaming approach, we developed the HomeRUN (Home Role-play for Understanding the Nexus) game, which allows players to act as homeowners and take behavioral and technological upgrade actions in a computer-simulation setting. The types of messages tested include social comparisons and resource-reduction measures across FEW sectors as well as information about the health, economic, and environmental impacts of FEW consumption. A game experiment with U.S. university students finds that social-comparison messages on food and energy consumption, but not on water, lead to significant reductions in household carbon emissions. In addition, messages associated with each type of FEW resource tend to lead to an immediate action corresponding to the particular FEW domain. These insights support a prioritization of intervention messaging for coordinated FEW conservation efforts at a household level. • U.S. households can conserve food, energy, water (FEW) resources to cut emissions. • A serious game is developed to test messages promoting sustainable behavior. • The study is the first to test the effectiveness of messaging across all FEW domains. • Social-comparison messages reduce food and energy emissions the most. • The use of periodic reminders can encourage FEW conservation behavior. [ABSTRACT FROM AUTHOR]

Individual pro-environmental attitudes and behaviors are determinant for long-term sustainability. We assessed profiles of an exclusive sample of 1351 households in the municipality of Gijón, Spain, in terms of their water consumption and recycling patterns using Latent Class Analysis (LCA). This methodology allows for households to be classified into groups without imposing any ad hoc criteria and provides information on the determinants of belonging to each group. The database includes the water consumption, self-reported environmental attitudes, and socioeconomic characteristics of the households. The results showed four significant household groups, where smaller families located in urban areas containing at least one homemaker and equipped with water efficient devices are more likely to present the best pro-environmental attitudes and behaviors related to water use and recycling habits. Furthermore, we found that providing better information in terms of water billing and the environmental impact of human behavior also fosters environmentally friendly habits. • Identification of environmentally-friendly households with latent class analysis. • Four clear profiles for water and recycling habits are found. • Small families with homemakers present better water-saving and recycling attitudes. • Rural households present higher water consumption and better recycling profiles. • Better information on the environment fosters good environmental attitudes. [ABSTRACT FROM AUTHOR]

Agricultural production consumes the majority of global freshwater resources. The worsening water scarcity has imposed significant stress on agricultural production when regions seek food self-sufficiency. To seek optimal allocation of spatial agricultural water and land resources in each water function zone of the objective region, a multi-objective optimization model was developed to tackle the trade-offs between the water-saving objective and the economic benefit objective considering virtual water trade (VWT). The cultivated area of each crop in each water function zone was taken into account as the decision variable, while a set of strong constraints were used to restrict land resources and water availability. Then, a decomposition-simplex method aggregation algorithm (DSMA) was proposed to solve this nonlinear, bounding-constrained, and multi-objective optimization model. Based on the quantitative analysis of the spatial blue and green virtual water in each agricultural product, the proposed methodology was applied to a real-world, provincial-scale region in China (i.e. , Jiangsu Province). The optimized results provided 18 Pareto solutions to reallocate the land resources in the 21 IV-level water function zones of Jiangsu Province, considering four major rainy-season crops and two dry-season crops. Compared to the actual scenario, the superior scheme increased by 7.95% (5.6 × 109 RMB) for economic trade and decreased by 1.77% (2.0 × 109 m3) for agricultural water consumption. It was mainly because the potential of spatial blue and green virtual water in Jiangsu was fully exploited by improving spatial land resource allocation. The food security of Jiangsu could be guaranteed by achieving self-sufficiency in the superior scheme, and the total VWT in the optimal scheme was 2.2 times more than the actual scenario. The results provided a systematic decision-support methodology from the perspective of spatial virtual water coordination, yet, the methodology is widely applicable. [Display omitted] • A methodology was developed for optimizing spatial allocation of agricultural water and land. • Trade-offs between economic benefits and water saving were tackled. • A decomposition-simplex method aggregation algorithm was proposed to solve the problem. • Optimal scheme alleviated regional water scarcity and achieved food self-sufficiency. • Total virtual water trade in the optimal scheme was greatly promoted. [ABSTRACT FROM AUTHOR]

Water resource shortage and water pollution are prominent and urgent resource and environment problems. Industrial water consumption and sewage discharges account for a large proportion of the total sewage discharge of China. Therefore, scientifically regulating the water consumption and sewage discharge of industrial enterprises can effectively alleviate water scarcity and pollution problems. By establishing a multi-agent model, this study simulates the water use behavior of industrial enterprises, exploring the responses of industrial enterprises to a different type of scenarios for water management that can coordinate economic and environmental benefits. The purpose is to reduce the water consumption and pollutant emissions of industrial enterprises while achieving economic benefits, so as to provide policy references for water authorities. The results show that: 1) The three policies of water price, water resource tax and emission reduction subsidy can effectively regulate the water consumption and sewage discharge of enterprises. 2) Water price and water resource tax rate need to be controlled within a reasonable range. Appropriate water price and water resource tax rate can encourage enterprises to increase R&D investment. On this basis, it is suggested to emphasize the two-way influence of the government and enterprises, continue to implement water resources management policies such as water resources tax, so as to promote the balance between ecology and economy. • It incorporates water use and sewage discharge of enterprises in the developed model. • It develops an ABM based framework to consider the interaction between agents. • The effect of policy portfolios in terms of tradeoffs was quantitatively evaluated. [ABSTRACT FROM AUTHOR]

The increasing frequency of drought events has intensified the risk of water scarcity, posing significant challenges for urban domestic water supply. Reducing urban household water consumption is an important way to alleviate water stress during drought periods. However, due to various factors, it is difficult to determine a water-saving target that is within the residents' capacity. Here, taking Beijing, China as an example, we explored the socio-psychological factors behind urban household water use behaviors under drought conditions, and further quantified the compressible ratio of water quotas for flexible water use behaviors. Therefore, the present study was based on the theory of planned behavior (TPB) and extended TPB (ETPB) by adding drought risk perception as a variable to the theoretical framework. With the help of questionnaire method and structural equation modeling (SEM), the explanatory power of TPB and ETPB in predicting people's water saving intention and behavior was compared. Meanwhile, mathematical statistical analysis methods were employed to calculate the water quota for elastic water consumption behavior and the compressible proportion of urban residents' elastic water consumption under drought conditions. The results showed that drought risk perception has a significant positive correlation with subject norms and water reduction behavior under drought conditions. Furthermore, ETPB was more effective in analyzing water use intentions and behaviors. The predictive explanatory power of SEM for reducing water use increased from 44% to 50% after adding drought risk perception variable. In terms of quantification of elastic water use behavior, the average total water consumption in summer and winter were 71.3L/(p.d) and 52.9L/(p.d) under drought conditions, while it were 124.3 L/(p.d) and 108.9 L/(p.d) under normal conditions. And the compressible proportions of the total water quota for summer and winter elastic water use were 46.7% and 56.8%, respectively. The calculation results can provide a reference for the government to make emergency water supply decisions against drought. • Socio-psychological factors behind urban household water use behaviors under drought conditions was explored using structural equation modeling. • Drought risk perception was introduced into theory of planned behavior as a variable to make the model more explanatory. • The concept of a compressible ratio of elastic water use behavior was introduced to quantify the law of water reduction in drought conditions. [ABSTRACT FROM AUTHOR]

The world faces imminent drought-related challenges that, from a tap-water supply perspective, require increasingly expensive infrastructure enhancement and energy expansion to maintain sufficient service levels. This paper argues that enhancing domestic water conservation provides a promising alternative or necessary addition to reduce costs and to stimulate pro-environmental behaviour. Although the number of field experiments on how people's behaviour can be changed with respect to their daily water consumption is growing, to date, most studies in this field have focussed either on explanatory socio-economic factors (e.g. water pricing, income, or family composition) or behavioural intentions and personal characteristics related to behavioural change. Accordingly, there is limited empirically validated knowledge about the use and effectiveness of different influencing tactics to change behaviour. This paper provides a review of the empirically oriented literature in this field and aims to provide an up-to-date assessment that identifies eight different Behavioural Influencing Tactics (BITs) that target long-term water conservation behaviour within households. Our analysis is structured around three information processing routes: the reflective route, the semi-reflective route, and the automatic route. We conclude that the current body of literature is promising and provides a useful body of evidence on the range and effectiveness of individual water conservation mechanisms, but that needs further development to deepen our understanding of how to effectively prolong and reinforce newly formed water conservation routines. • This paper is a review of empirical studies about Behaviour Influencing Tactics (BITs) for domestic water conservation. • The BITs are: knowledge transfer, self-efficacy, social norms, framing, tailoring, emotional shortcuts, priming, & nudging. • Our understanding of the effectiveness of BITs is evolving but knowledge about sustaining water conservation behaviour over time is limited. • For achieving long-term water conservation habits, a well-aligned conjunctive use of different BITs is crucial. [ABSTRACT FROM AUTHOR]

Improving the effectiveness and economics of strategies to remediate groundwater nitrate pollution is a matter of concern. In this context, the addition of whey into aquifers could provide a feasible solution to attenuate nitrate contamination by inducing heterotrophic denitrification, while recycling an industry residue. Before its application, the efficacy of the treatment must be studied at laboratory-scale to optimize the application strategy in order to avoid the generation of harmful intermediate compounds. To do this, a flow-through denitrification experiment using whey as organic C source was performed, and different C/N ratios and injection periodicities were tested. The collected samples were analyzed to determine the chemical and isotopic composition of N and C compounds. The results proved that whey could promote denitrification. Nitrate was completely removed when using either a 3.0 or 2.0 C/N ratio. However, daily injection with C/N ratios from 1.25 to 1.5 seemed advantageous, since this strategy decreased nitrate concentration to values below the threshold for water consumption while avoiding nitrite accumulation and whey release with the outflow. The isotopic results confirmed that nitrate attenuation was due to denitrification and that the production of DIC was related to bacterial whey oxidation. Furthermore, the isotopic data suggested that when denitrification was not complete, the outflow could present a mix of denitrified and nondenitrified water. The calculated isotopic fractionation values (ε 15N NO3/N2 and ε 18O NO3/N2) might be applied in the future to quantify the efficiency of the bioremediation treatments by whey application at field-scale. • Whey can be recycled to promote nitrate attenuation. • Daily injection at a C/N ratio of 1.25–1.5 avoided whey release with the outflow. • The δ15N and δ18O of NO 3 − confirmed that denitrification caused the attenuation. • The δ13C of DIC and DOC demonstrated the production of DIC from whey oxidation. [ABSTRACT FROM AUTHOR]

A detailed techno-economic comparison of a chemical scrubber (CS) and a bio-filter (BF) was conducted over a 45-day time period at a municipal wastewater treatment plant (WWTP), Yazd city. The assessment of emissions quantity indicated that odor emissions from the Yazd WWPT mainly consist of hydrogen sulfide (H 2 S) and ammonia (NH 3). It was also found that odor gaseous loading changes corresponding to water consumption pattern in society (R2 = 0.922) for H 2 S and (R2 = 0.978) for NH 3. The highest level of 25 and 3 ppm for H 2 S and NH 3 , respectively were detected at specific times during the day. The BF system was continuously supplied with Yazd WWPT's off-gas treatment while the CS was only examined at the times during the day when the gas emissions are at the highest level. The removal efficiency of NH 3 and H 2 S were found to be affected by their respective loading rate. Additionally, among the various oxidants examined in the CS, the NaOCl solution showed the best results in terms of removal efficiency and compatibility. The experiment revealed almost complete removal of NH 3 while the H 2 S removal efficiency remained above 95% for both systems regardless of the operating conditions. This study clearly demonstrates the effectiveness of both systems in treating actual waste gases containing H 2 S and NH 3. By comparing the gas loading rate of both systems and considering limitations of the BF system, the CS seems to be more efficient applicable odor control technology from a technical viewpoint. From the economic viewpoint, comparisons revealed that chemical usage and operating expenses were costly parts of the CS and the BF, respectively. The economic indexes of 1.58 €.m−3. h−1 and 2.57 €.m−3. h−1 were obtained for the BF and CS, respectively, reflecting cost-effectiveness of the BF system. Biofiltration and chemical scrubbing are comparatively evaluated in treating actual waste gases containing H 2 S and NH 3 during a 45-day time period at a municipal WWTP in terms of environmental performance and process economics. Image 1 • Developing a chemical scrubber and a biofilter for simultaneous removal of H 2 S and NH 3. • Using the effluent of municipal wastewater treatment plant to evaluate the systems capability. • A detailed techno-economic comparison of a scrubber and a biofilter over a 45-day time period. • Suggestion of NaOCl with flow rate of 7 L/min as the best scrubbing liquid. • Achievement of high removal efficiency regardless of gas loading rate used. [ABSTRACT FROM AUTHOR]

For water companies, benchmarking their performance relative to other companies can be an effective way to identify the scope for efficiency gains to be made through infrastructure investment and operational improvements. However, a key limitation to benchmarking is the confounding effect of exogenous factors, which may not be factored in to benchmarking methodologies. The purpose of this study was to provide an unbiased comparison of efficiency across a sample of water and sewage companies, accounting for important exogenous factors. Bias-corrected economic and environmental efficiency estimates with explanatory factors were evaluated for a sample of 13 water and sewage companies in the UK and Ireland, using a double-bootstrap data envelopment analysis (DEA) approach. Bias correction for economic and environmental efficiency changed the rankings of nine and eight companies, respectively. On average, companies could reduce economic inputs by 19% and carbon outputs by 16% if they performed at the efficiency frontier. Variables explaining efficiency were: source of water, leakage rate, per capita consumption and population density. Population density showed statistical significance with both economic (p-value 0.002) and environmental (p-value 0.001) efficiency. Consequently, a rurality factor was defined for each company's operational area, which was then regressed against normalised water company performance data. More rural water companies spend more per property (R2 of 0.633), in part reflecting a larger number of smaller sewage treatment works serving rural populations (R2 of 0.823). These findings provide new insight into methods for benchmarking, and factors affecting, water company efficiency, pertinent for both regulators and water companies. • Economic and environmental inputs could reduce by 19.4% and 15.8%. • Bias correction changed the rankings of over 65% of companies. • Population density and surface water % significantly linked to higher efficiencies. • Rurality has relationship with increased spending (R2 of 0.63). • No. of sewage treatment works linked to rurality/spending relationship (R2 of 0.82). [ABSTRACT FROM AUTHOR]

Abstract Decreasing per capita water consumption in several OECD countries has led to a notable flow reduction into sewer systems. However, sewers still transport similar quantities of solids and pollutants, leading to increased wastewater concentration and, potentially, excess solids deposition. The shift towards decentralised water schemes in cities and widely reported changes in rainfall patterns cast additional uncertainty on future wastewater quality and flows into sewers. Excess solids deposition in sewers can cause increased environmental pollution risks at Combined Sewer Overflows from solids resuspension and reduced sewer hydraulic capacities. This review analyses the magnitude of excess solids deposition due to changing wastewater composition and evaluates current approaches to modelling sewer solids. Gaps in commonly used modelling approaches for deposited bed processes, specifically in bed consolidation and bed particle cohesion processes, and gross solids transport were identified and addressed to enable better solids risk prediction and management. Graphical abstract Image 1072 Highlights • Future water use practices will increase the risk of excess sewer solids deposition. • There is a need to enhance certain aspects of current sewer solids models. • A pathway for the development and scaling up of an enhanced model is discussed. [ABSTRACT FROM AUTHOR]

Abstract Dietary-related risks rank top among all the health risks in many countries. The 2nd United Nations Sustainable Development Goal aims to end hunger, achieve food security and improved nutrition and promote sustainable agriculture. Yet whether improving nutritional quality also benefits the environment is still under-explored, particularly for developing countries. China is an interesting and important case because of its rapidly changing dietary patterns distinct from the western countries studied in the literature, sub-national level heterogeneity, socio-economic characteristics and lifestyles, as well as its considerable population. This paper evaluates greenhouse gas (GHG) emissions, water consumption, and land appropriation resulting from shifting the Chinese population to healthy diets. We quantify the environmental impacts of individual diets using the latest available data of China Health and Nutrition Survey (2011), and compare them with the environmental impacts of suggested healthy dietary patterns in accordance with the 2016 Chinese Dietary Guidelines. If all Chinese would follow healthy diets rather than their current diets revealed in the survey, GHG emissions, water consumption, and land occupation would increase by 7.5% (63.9 Mt CO 2 e annually), 53.5% (510 billion m3), and 54.2% (1256 billion m2), respectively. Urban and high-income groups have higher diet-related environmental impacts but could achieve less additional environmental impacts when moving to healthier diets. These findings indicate an expense of increased GHG emissions, and consumption of water and land resources in improving health. They also highlight the need to focus on the effects of improved economic conditions and urbanization in reconciling environmental impacts and human nutritional adequacy. Highlights • Shifting to healthy diets in China leads to 7.5% lower GHG emissions. • Water consumption and land use increase by 53.5% and 54.2% because of the shift. • Urban dwellers and high-income groups deliver larger reductions in GHG emissions. • Increase of water consumption and land use is also smaller for these groups. [ABSTRACT FROM AUTHOR]

Abstract Due to limited economic resources, which impede access to specific advanced technologies, many developing countries are still facing the challenge of reducing human exposure to heavy metals, which is primarily associated with the consumption of water contaminated through the discharge of poorly treated wastewater. In wastewater treatment technology, adsorption is sometime preferred to other approaches because of its high efficiency, easy handling, availability of different substrates and cost effectiveness. Moreover, increasing emphasis has recently been given to the use of low-cost adsorbents (generally solid wastes) for the treatment of polluted water, with a resulting double benefit for the environment. In this paper, the use of red mud and pyrolusite has been investigated for the removal of As and Mn from drinking water. Adsorption equilibrium data have been examined through the application of constant temperature models (isotherms), while batch and dynamic tests have been used to clarify the effects of pH, initial metal ion concentration and temperature on the adsorption performance, aiming at identifying the best conditions for the treatment. The combined use of the two adsorbents allows exploiting their properties synergistically, maximizing efficacy and sustainability without affecting process design and costs. In particular, 'clean' water (i.e. water with heavy metals contents below law limits) has been obtained even after the passage of a volume of solution higher than 40 bed volumes, and considering initial unrealistically high concentrations for the metals. Highlights • Mn and As are removed till traces level using low-cost adsorbents from solid wastes. • Adsorption takes place with a complex dynamic, yet describable by classic models. • The two metals behave very differently, with As being removed more effectively. • Coupled adsorbents maximize efficacy and sustainability without affecting costs. • No advanced technology required for the effective treatment of drinking water. [ABSTRACT FROM AUTHOR]

Abstract The attainment of sustainable development in water and sanitation i.e. Sustainable Development Goal 6 (SDG 6) requires a comprehensive monitoring and knowledge base of social and economic water needs at national scale in such a way that should not cause negative environmental manifestations from regional to global scale. India holds a key position among developing economies with a complex interconnected web of fast-growing population, coupled with biophysical stress, social deprivation and economic inequality related to utilization, availability and access to water resources and sanitation facilities. This study addresses some of these challenges related to monitoring and implementation of the targets of the UN SDG 6 in India. Acknowledging the contribution of society and economy in sustainability paradigm, here we have chosen 28 indicators (clustered into 11 dimensions) under two major groups, concerning biophysical and social development aspects of water and sanitation. We have shown declining level of per capita biophysical water resource and slow to rapidly developing societal indicators related to SDG 6 in India. From past trends, we have calculated probable scenario of biophysical consumption of India up to 2050. We have also analysed the interrelationship of water and sanitation (SDG 6) with health (SDG 3) and end to poverty (SDG 1) in India. These show a positive impact of increasing per capita GDP on improving sanitation related indicators, which in turn positively influence to reduce water and sanitation related diseases, especially in children and aged population. This cumulative assessment framework contributes a tool to prioritize water resource appropriation and assessment of sanitation, management response and policy implementations to national level inclusive sustainability of water and sanitation sector, keeping in mind the societal and economic development scenario in India. Highlights • Water withdrawal in India has crossed global per capita freshwater use PB in 2010. • 7 of 11 biophysical indicators showing decline related to SDG 6. • 11 of 17 social development indicators are not going to reach UN SDG 2030 criteria. • Water requirement is going to increase almost 1.3 times in 2050. [ABSTRACT FROM AUTHOR]

Abstract Given regulatory developments, it is imperative that water businesses implement effective customer engagement strategies. Among other options, Facebook offers enormous potential given the ability to connect with customers, involve customers in the co-creation of content, obtain real-time feedback on customer preferences and promote water conversation behaviours. This paper examines how effectively 20 large Australian and U.K. water businesses are using Facebook to engage customers. It also identifies how these firms can improve Facebook engagement by optimising posts type, timing, content, frequency and other factors. The total sample included more than 300,000 responses to nearly 17,000 posts between 2010 and 2017. Rapid growth in the utilisation of Facebook by water businesses was observed given the number of posts and customers engaging with this content. The results of the analysis of popular posts identified innovative ways some water businesses are using Facebook posts to promote the health benefits of tap water consumption, water conservation behaviours and responsible wastewater practices. Despite the trends, most firms still make less than one post per day and of those customers who have engaged, most have done with a single response. Further analysis revealed that few posts, and only a relatively small number of customer comments, pertained to water pricing matters. To promote engagement, water businesses must improve post regularity, the degree to which they moderate Facebook discussion, the utilisation of videos and photos, and further consider the underlying content of posts. Highlights • There has been a rapid growth in the utilisation of Facebook by water businesses given the number of posts and customers engaging with this content. • Top firms are using Facebook to engage customers in infrastructure projects and promote conservation and responsible wastewater behaviours. • To improve engagement, firms should increase post regularity, Facebook moderation, the use of videos and photos, and refine post content. [ABSTRACT FROM AUTHOR]

The current transition toward added renewables into the power mix is essential to mitigate climate change effects, but the energy transition has environmental impacts outside the scope of greenhouse gas emissions that also need attention. One such impact is the water-energy dependency nexus, where water dependencies are also seen for non-fossil technologies such as concentrated solar power (CSP), bioenergy and hydropower and mitigation technologies such as carbon capture and storage (CCS). In this light, the selection of power production technologies can potentially affect long-term water resource renewability and dry summer conditions, causing, e.g., power plant shutdowns. In this study, we employ an established and validated scheme of water consumption and withdrawal rates across energy conversion technologies at the European scale to project corresponding water usage rates towards 2050 for EU30 countries. We further use the entire range of global- and regional climate model ensembles for low-, medium- and high-emission scenarios to project trends and robustness estimates of freshwater resources and availability at the distributed level for corresponding countries and years towards 2100. The results show a high sensitivity of water usage rates to the implementation of energy technologies such as CSP and CCS, as well as the decommissioning rates of fossil technologies and some scenarios generally show unaltered or even vastly increasing water consumption and withdrawal rates. Further, the assumptions on using CCS technologies, an evolving field, show a high impact. The assessment of hydro-climatic projections showed some degree of overlaps between decreasing water availabilities and increasing power sector water usage, especially for one power production scenario with a high share of CCS implementation. Further, a vast climate model spread in water availability was seen for both yearly means and summer minima, emphasising the need to include extremes in water management, and the water availability was highly dependent on the emission scenario in some regions. • Future EU water withdrawal and consumption of five energy scenarios was assessed. • Renewable energy is not necessarily compatible with renewable water resources. • The future renewable energy mix can cause significant increases in water usage. • CCS technologies, CSP, bio-energy and geothermal have high water usage rates. • The future water availability is increasingly at risk in some regions and scenarios. [ABSTRACT FROM AUTHOR]

The sustainability of industrial production, especially for highly water-demanding processes, is strictly related to water resource availability and to the dynamic interactions between natural and anthropogenic requirements over the spatial and temporal scales. The increase in industrial water demand raises the need to assess the related environmental sustainability, facing the occurrence of global and local water stress issues. The identification of reliable methodologies, based on simple indices and able to consider the impact on local water basins, may play a basilar role in water sustainability diagnosis and decision-making processes for water management and land use planning. The present work focalized on the definition of a methodology based on the calculation of indicators and indices in the view of providing a synthetic, simple, and site-specific assessment tool for industrial water cycle sustainability. The methodology was built starting from geo-referenced data on water availability and sectorial uses derived for Italian sub-basins. According to the data monthly time scale, the proposed indices allowed for an industrial water-related impacts assessment, able to take into account the seasonal variability of local resources. Three industrial factories, located in northern (SB1, SB2) and central (SB3) Italian sub-basins, were selected as case studies (CS1, CS2, CS3) to validate the methodology. The companies were directly involved and asked to provide some input data. The methodology is based on the calculation of three synthetic indexes: the Withdrawal and Consumption water Stress Index (WCSI) allowed for deriving a synthetic water stress level assessment at the sub-basin scale, also considering the spatial and temporal variations; the industrial water use sustainability assessment was achieved by calculating the Overall Factory-to-Basin Impact (OFBI) and the Internal Water Reuse (IWR) indices, which allowed a preliminary evaluation of the factories' impacts on the sub-basin water status, considering the related water uses and the overall pressures on the reference territorial context. The WCSI values highlighted significant differences between the northern sub-basins, characterised by limited water stress (WCSI SB1 = 0.221; WCSI SB2 = 0.047), and the central ones, more subjected to high stress (WCSI SB3 = 0.413). The case studies CS1 and CS3 showed to exert a more significant impact on the local water resource (OFBI CS1 = 0.18%; OFBI CS2 = 0.192%) with respect to CS2 (OFBI = 0.002%), whereas the IWR index revealed the different company's attitude in implementing water reuse practices (IWR CS1 = 40%; IWR CS1 = 27%; IWR CS1 = 99%). The proposed methodology and the indices may also contribute to assessing the effectiveness of river basin management actions to pursue sustainable development goals. [Display omitted] • Set-up of a methodology to assess industrial water management sustainability. • Indicators to analyse sub-basin water status and productive sites water uses. • Proposal of synthetic indices to assess industrial impacts on local water resources. • Inter-annual variability of water resources and high spatial resolution are included. • Productive sites used as case studies to validate the proposed methodology. [ABSTRACT FROM AUTHOR]

Drought severity is expected to increase in South Africa in the coming years, given the deteriorating effects of climate change on rainfall patterns, global temperature, and evaporation. A common mitigation strategy adopted by households is to promote water demand management initiatives to reduce water consumption volume and complement existing water supply management approaches implemented by suppliers. This study contributes to the discussion on adaptation strategies by investigating household preference heterogeneity for water-saving technologies through empirical evidence from urban Cape Town, South Africa. Using a choice modelling framework, we collected primary survey data from 512 urban households in five of the city's major suburbs and investigated heterogeneity among the households based on their preferences for characteristics embedded in four water-saving technologies. Four preference classes were identified by accounting for taste heterogeneity. Overall, respondents had the highest marginal willingness to pay (MWTP) for the greywater technology alternative at 17,025 ZAR (US$ 1142) while rainwater technology has the least willingness to pay value at 5206 ZAR (US$ 349). In addition, the results show that respondents in classes 1 and 2 have a high interest in technologies that save a large quantity of water, whereas members of classes 3 and 4 rely on inexpensive conservation and behavioral habits as climate adaptation measures. This study has important policy implications for many water-stressed and arid cities within and outside South Africa since like Cape Town, many large cities require long-lasting measures that help reduce the pressure on their strained water systems. • Water-saving technologies improve residential water demand in drought-prone cities. • We identified four preference classes by accounting for taste heterogeneity. • Respondents in class 3 and class 4 tend to fall in the lowest income bracket. • Policy interventions should provide financial support to low-income households. [ABSTRACT FROM AUTHOR]

The development of social economy often requires a large consumption of water resources, and will also discharge a large amount of pollutants to the environment. Currently, the rapid development of regional water resources, social economy and ecological environment (WSE) complex system encounters significant challenges, and the coordination development of WSE complex system becomes important and necessary condition of regional sustainable development. Therefore, to scientifically evaluate the coordination development state of WSE system, based on the establishment of evaluation index system, the connection number and distance coordination model coupling approach for the coordination development evaluation of WSE complex system was proposed in this manuscript. The application results of the proposed method in Anhui Province, China indicate that, during 2011–2020, the coordination level of Anhui province is relatively high, and the coordination grade of most cities are in grade I or II. The coordination development degree of Anhui province presented a distinct improving trend with time, from most cities in grade IV or V in 2011 to most cities in grade II in 2020, from the worst 0.0580 in 2011 to the best 0.9200 in 2020. In terms of space, the coordinated development level of southern Anhui is higher than that of northern Anhui. Meanwhile, the coordination development status of the 16 cities in Anhui province can be divided into three patterns according to its historical variation characteristics, i.e. , coordination development mode, ecological environment backward mode, and social and economic backward mode. Compared with the commonly used coordination evaluation method, the method of this paper can solve the problem of homogenization, and its calculation results are more reasonable and practical. • The evaluation indicator system for the coordination of WSE system is established. • A coordination development evaluation model based on connection number is proposed. • The coordinated development degree of Anhui province from 2011 to 2020 is evaluated. [ABSTRACT FROM AUTHOR]

To analyze the water use conflict and its driving factors between wetland and agriculture at both regional and local scales, agricultural water consumption and wetland water storage changes in the Sanjiang Plain, the main grain-producing area in Heilongjiang Province of Amur River Basin, were investigated based on statistical data, field survey and GIS calculation. A specific case study in the Qixing River National Nature Reserve (QNNR) wetland-farmland system was completed using a water balance approach. Results showed that the proportion of agricultural water increased from 71.8% to 88.0% while that of ecological water only hovered around approximately 1% in Heilongjiang Province during 2004–2015. Due to wetland loss and degradation, the total surface water storage in the Sanjiang Plain wetlands decreased from 14.46 × 10 9  t in the 1980s to 4.70 × 10 9  t in 2010. Agricultural development in successive years, and the dramatic increased requirement for water in paddy fields, intensified the water use conflict between wetlands in the QNNR and surrounding farmlands. Groundwater extraction for irrigation was approximately twice as high as the total infiltration recharge from wetlands and farmlands. It is concluded that the degraded natural water resource endowments are struggle to sustainably support stable grain production as a mainstay of national food safety, which determined the competitive relationship between wetland and agriculture. To mitigate this conflict, adaptive wetland (e.g. water transfer at stagger time, precise water recharge, resourced meltwater) and agricultural techniques (e.g. water-saving irrigation and planting, soil water capacity increment, rainfed agriculture) and five key management solutions were recommended. [ABSTRACT FROM AUTHOR]

The increasing recycling of polyethylene terephthalate ( PET) bottles requires more and more fresh water during washing the bottles. The post-washing wastewater is often treated as effluent, whereas it could be reused in the technological process after appropriate pretreatment. In this paper, coagulation together with flocculation is proposed for use in the pretreatment of the wastewater arising during PET bottles washing. Five flocculants and six coagulants were tested. The turbidity and total organic carbon (TOC) were reduced by up to 98% and 69%, respectively. Out of the tested flocculants, Praestol 611 BC at a dose of 2 mg/dm 3 had the best performances. The best coagulant in TOC reduction was PIX-123. As for turbidity reduction, ALS was the best, but PIX-123 was comparable, and therefore, PIX-123 was indicated as most suitable in simultaneous reduction of TOC and turbidity. The coagulation and flocculation together reduced the amount of pollutants and contaminants in the post-washing wastewater to the levels allowing the water to be reused in the washing process, which could bring both economical and ecological benefits. [ABSTRACT FROM AUTHOR]

This study assessed the potential for potable water savings in a building by using stormwater filtered by a porous asphalt pavement located in a parking lot. Stormwater is meant to be used for non-potable purposes (flushing toilets and urinals). Two models of porous pavement systems were constructed, both with porous asphalt mixture over a different combination of porous granular layers. The models were assessed for their filtering capacity; samples of stormwater runoff were collected in a parking lot located near the building where filtered stormwater is meant to be used. The models showed to be capable of filtering some pollutants. However, additional water treatment would be necessary to obtain the quality required for non-potable uses. Then one model was selected for a theoretical analysis on using it in a parking lot. The potential for potable water savings was analysed considering four scenarios as a function of daily local rainfall data. The thickness of the temporary stormwater reservoir layer was calculated in order to meet the design rainfall adopted, and the stormwater tank capacity was estimated using the Netuno computer programme. As a result, using a 45,000-litre stormwater tank, potable water savings of at least 53% would be obtained if filtered stormwater were used to flush toilets and urinals. This indicates that porous pavements show a great potential for filtering stormwater runoff to be used in buildings. [ABSTRACT FROM AUTHOR]

In this study, an integrated water and waste load allocation model is proposed to assist decision makers in better understanding the trade-offs between economic growth, resource utilization, and environmental protection of coal chemical industries which characteristically have high water consumption and pollution. In the decision framework, decision makers in a same park, each of whom have different goals and preferences, work together to seek a collective benefit. Similar to a Stackelberg-Nash game, the proposed approach illuminates the decision making interrelationships and involves in the conflict coordination between the park authority and the individual coal chemical company stockholders. In the proposed method, to response to climate change and other uncertainties, a risk assessment tool, Conditional Value-at-Risk (CVaR) and uncertainties through reflecting parameters and coefficients using probability and fuzzy set theory are integrated in the modeling process. Then a case study from Yuheng coal chemical park is presented to demonstrate the practicality and efficiency of the optimization model. To reasonable search the potential consequences of different responses to water and waste load allocation strategies, a number of scenario results considering environmental uncertainty and decision maker' attitudes are examined to explore the tradeoffs between economic development and environmental protection and decision makers' objectives. The results are helpful for decision/police makers to adjust current strategies adapting for current changes. Based on the scenario analyses and discussion, some propositions and operational policies are given and sensitive adaptation strategies are presented to support the efficient, balanced and sustainable development of coal chemical industrial parks. [ABSTRACT FROM AUTHOR]

Low-carbon transition in the non-electric energy sector, which includes transport and heating energy, is necessary for achieving the 2 °C target. Meanwhile, as non-electric energy accounts for over 60% of total water consumption in the energy supply sector, it is vital to understand future water trends in the context of decarbonization. However, few studies have focused on life-cycle water impacts for non-electric energy; besides, applying conventional LCA methodology to assess non-electric energy has limitations. In this paper, a Multi-Regional Hybrid Life-Cycle Assessment (MRHLCA) model is built to assess total CO 2 emissions and water consumption of 6 non-electric energy technologies – transport energy from biofuel and gasoline, heat supply from natural gas, biogas, coal, and residual biomass, within 7 major emitting economies. We find that a shift to natural gas and residual biomass heating can help economies reduce 14–65% CO 2 and save more than 21% water. However, developed and developing economies should take differentiated technical strategies. Then we apply scenarios from IMAGE model to demonstrate that if economies take cost-effective 2 °C pathways, the water conservation synergy for the whole energy supply sector, including electricity, can also be achieved. [ABSTRACT FROM AUTHOR]

Hydrometallurgical processes for the treatment and recovery of metals from waste electrical and electronic equipment produce wastewaters containing heavy metals. These residual solutions cannot be discharged into the sewer without an appropriate treatment. Specific wastewater treatments integrated with the hydrometallurgical processes ensure a sustainable recycling loops of the electrical wastes to maximize the metals recovery and minimize the amount of wastes and wastewaters produced. In this research activity the efficiency of ultrafiltration combined with surfactant micelles (micellar-enhanced ultrafiltration) was tested to remove metals form leach liquors obtained after leaching of NiMH spent batteries. In the micellar-enhanced ultrafiltration, a surfactant is added into the aqueous stream containing contaminants or solute above its critical micelle concentration. When the surfactant concentration exceeding this critical value, the surfactant monomers will assemble and aggregate to form micelles having diameter larger than the pore diameter of ultrafiltration membrane. Micelles containing contaminants whose diameter is larger than membrane pore size will be rejected during ultrafiltration process, leaving only water, unsolubilized contaminants and surfactant monomers in permeate stream. The experiments are carried out in a lab-scale plant, where a tubular ceramic ultrafiltration membrane is used with adding a surfactant to concentrate heavy metals in the retentate stream, producing a permeate of purified water that can be reused inside the process, thus minimizing the fresh water consumption. [ABSTRACT FROM AUTHOR]

Population growth, coupled with declining water availability and changes in climatic conditions underline the need for sustainable and responsive water management instruments. Supply augmentation and demand management are the two main strategies used by water utilities. Water demand management has long been acknowledged as a least-cost strategy to maintain water security. This can be achieved in a variety of ways, including: i) educating consumers to limit their water use; ii) imposing restrictions/penalties; iii) using smart and/or efficient technologies; and iv) pricing mechanisms. Changing water consumption behaviours through pricing or restrictions is challenging as it introduces more social and political issues into the already complex water resources management process. This paper employs a participatory systems modelling approach for: (1) evaluating various forms of a proposed tiered scarcity adjusted water budget and pricing structure, and (2) comparing scenario outcomes against the traditional restriction policy regime. System dynamics modelling was applied since it can explicitly account for the feedbacks, interdependencies, and non-linear relations that inherently characterise the water tariff (price)-demand-revenue system. A combination of empirical water use data, billing data and customer feedback on future projected water bills facilitated the assessment of the suitability and likelihood of the adoption of scarcity-driven tariff options for a medium-sized city within Queensland, Australia. Results showed that the tiered scarcity adjusted water budget and pricing structure presented was preferable to restrictions since it could maintain water security more equitably with the lowest overall long-run marginal cost. [ABSTRACT FROM AUTHOR]

Rapid urban growth in Mediterranean cities has become a serious environmental concern. Due to this expansion, which covers adjacent horizontal ground, a critical deficit of green areas has been increasing. Moreover, irrigation is considered an important issue since water is one of the most limiting natural resources all over the world. The main objective of this study was to perform a long-term experiment to assess five Mediterranean species for extensive green roof implementation in Mediterranean-climate conditions. Brachypodium phoenicoides , Crithmum maritimum , Limonium virgatum , Sedum sediforme and Sporobolus pungens were grown in experimental modules under well-watered and water-limited conditions (irrigation at 50% and 25% ET 0 , respectively). Plant growth and cover, relative appearance, color evolution and water use were determined periodically for two years. Shoot and root biomass were quantified at the end of the experimental period. The effects of the irrigation treatments and seasonal changes were assessed to identify the advantages and disadvantages of each species according to their environmental performance. All species survived and showed adequate esthetic performance and plant cover during the experiment. S. sediforme registered the lowest variation of relative appearance along the experiment, the highest biomass production and the lowest water consumption. Nevertheless, B. phoenicoides appeared to be an interesting alternative to S. sediforme , showing high esthetic performance and water consumption throughout the rainy season, suggesting a potential role of this species in stormwater regulation related with runoff reduction. S. pungens performed well in summer but presented poor esthetics during winter. [ABSTRACT FROM AUTHOR]

This paper addresses the synthesis problem of non-isothermal water networks using a mathematical programming approach. A heat-integrated water network superstructure and its corresponding mixed integer nonlinear programming (MINLP) model is proposed for the synthesis of individual as well as interplant water networks. A new feature of the proposed model includes piping installation cost within the objective function minimising the total annual cost of the network. This introduces additional trade-offs between operating and investment costs that can impact a final network design. Three examples were solved in order to demonstrate the applicability and effectiveness of the proposed model and solution approach. The results show that additional saving in total annual cost can be achieved by enabling direct water integration between plants. Improved solutions were obtained compared to those reported in the literature considering freshwater and utilities consumption as well as total annual cost. [ABSTRACT FROM AUTHOR]

While the sustainability of resource depletion is a longstanding environmental concern, wider attention has recently been given to growing water scarcity and groundwater depletion. This study seeks to test the substitutability assumption embedded in weak sustainability indicators using a case study of Californian water supply. The volume of groundwater depletion is used as a proxy for unsustainable water consumption, and defined by synthesising existing research estimates into low, medium and high depletion baselines. These are compared against projected water supply increases from ocean desalination and water recycling by 2035, to determine whether new, drought-proof water sources can substitute for currently unsustainable groundwater consumption. Results show that the maximum projected supply of new water, 2.47 million acre-feet per year (MAF/yr), is sufficient to meet low depletion estimates of 2.02 MAF/yr, but fails to come near the high depletion estimate of 3.44 MAF/yr. This does not necessarily indicate physical limitations of substitutability, but more so socio-economic limitations influenced by high comparative costs. By including capacities in demand-substitutability via urban water conservation, maximum predicted capacities reach 5.57 MAF/yr, indicating wide room for substitution. Based on these results, investment in social and institutional capital is an important factor to enhance demand-side substitutability of water and other natural resources, which has been somewhat neglected by the literature on the substitutability of natural resources. [ABSTRACT FROM AUTHOR]

Energy and water resources are closely linked in electric power systems, and the application of low-carbon technologies further affects electricity generation and water consumption in those systems. The holistic optimization of electric power systems, including generation and decarbonization processes, is necessary. Few studies have considered the uncertainty associated with the application of low-carbon technologies in electric power systems optimization from an energy-water nexus perspective. To fill such a gap, this study developed a simulation-based low-carbon energy structure optimization model to address the uncertainty in power systems with low-carbon technologies and generate electricity generation plans. Specifically, LMDI, STIRPAT and grey model were integrated to simulate the carbon emissions from the electric power systems under different socio-economic development levels. Furthermore, a copula-based chance-constrained interval mixed-integer programming model was proposed to quantify the energy-water nexus as the joint violation risk and generate risk-based low-carbon generation schemes. The model was applied to support the management of electric power systems in the Pearl River Delta of China. Results indicate that, the optimized plans could mitigate CO 2 emission by up to 37.93% over 15 years. Under all scenarios, more low-carbon power conversion facilities would be established. The application of carbon capture and storage would increase energy and water consumption by up to [0.24, 7.35] × 106 tce and [0.16, 1.12] × 108 m3, respectively. The optimization of the energy structure based on energy-water joint violation risk could reduce the water utilization rate and the carbon emission rate by up to 0.38 m3/104 kWh and 0.04 ton-CO 2 /104 kWh, respectively. • A simulation-based inexact optimization model for power systems planning. • A low-carbon electric power system was optimized under uncertainty. • CO 2 emissions under different socio-economic development levels were simulated. • The scale of generation facilities was optimized under different risk combinations. [ABSTRACT FROM AUTHOR]

Ecological restoration is an important approach to improving landscape sustainability. However, ecological restoration in drylands is strongly limited by water resources. Therefore, a technical route for ecological restoration in drylands that creates sustainable landscapes based on those water constraints is needed. In this study, we develop a spatially explicit framework named "Constraint-Pattern-Benefit" to plan ecological restoration patterns in Inner Mongolia, China. Based on a prediction of the ecosystem service (ES) increase under limited evapotranspiration as a water constraint, we constructed 5 landscape sustainability-related strategies with 100 ecological restoration scenarios, which considered fragmentation of restoration locations, distance to city, water consumption, and the allocation scale to determine the spatial arrangement of ecological restoration. Results show that the ES increase potential of ecological restoration under water constraints is distributed in the center of Inner Mongolia. The multi-objective scenario simultaneously achieves 59.1% water yield, 74.2% soil conservation, 57.2% sand fixation, and 52.8% carbon sequestration with 50% restored landscape. Considering the indicators of fragmentation, water consumption, and distance to city decreases the restored landscape fragmentation from 0.44 to 0.26, improves the restoration efficiency by 14.41%, and increases the beneficiary population by 35.5%, respectively. Small-scale allocation can further increase the ES realization efficiency, which is on average 4.8% higher at the city scale than at the provincial scale. Moreover, this approach focuses on the sustainable effect of the spatial arrangement on dryland landscapes at different scales, which provides methodological support for improving the sustainability of drylands. • A "Constraint-Pattern-Benefit" framework is established for planning ecological restoration arrangement in drylands. • Water constraints limit ESs increase potential in drylands. • Multi-objective ecological restoration can achieve a win-win situation between ESs increase. • Suburban and intensive restoration strategies affect ES realization efficiency and the beneficiary. • Small-scale allocation can increase the ES realization efficiency while enhancing the impact of other strategies. [ABSTRACT FROM AUTHOR]

Greywater is an important alternative water source, particularly in semi-arid, touristic areas, where the biggest water demand is usually in the dry period. By using this source wisely, tourist facilities can substantially reduce the pressure to scarce water resources. In densely urbanized touristic areas, where space has high value, compact solutions such as MBR based greywater reuse systems appear very appropriate. This research focuses on technical and economical evaluation of such solution by implementing a pilot MBR to a hotel with separated grey water. The pilot was operated for 6 months, with thorough characterisation of the GW performed, its operation was monitored and its energy consumption was optimized by applying a control system for the air scour. Based on the pilot operation a design and economic model was set to estimate the feasibility (CAPEX, OPEX, payback period of investment) of appropriate scales of MBR based GW systems, including separation of GW, MBR technology, clean water storage and disinfection. The model takes into account water and energy prices in Spain and a planning period of 20 years. The results demonstrated an excellent performance in terms of effluent quality, while the energy demand for air-scour was reduced by up to 35.2%, compared to the manufacturer recommendations. Economical evaluation of the entire MBR based GW reuse system shows its feasibility for sizes already at 5 m 3 /day (60 PE). The payback period of the investment for hotels like the demonstration hotel, treating 30 m 3 /day is 3 years. [ABSTRACT FROM AUTHOR]

Groundwater markets improve the agricultural economy by transferring water entitlements from low-efficient users to high-efficient ones to maximize productivity. Aiming at developing an efficient groundwater market, the environmental effects of the market mechanism should be assessed, and a reliable method for monitoring water consumption needs to be employed. Toward this end, this paper proposes three annual smart groundwater market mechanisms to maximize water net benefits, minimize groundwater withdrawal, and precisely measure water consumption in agricultural fields. To guarantee the aquifer's safe yield in each mechanism, a groundwater simulation model (i.e., Groundwater Modeling System (GMS)) is used to control groundwater table drawdown at the end of the planning horizon. In addition, the fields' evapotranspiration (ET) is estimated using Surface Energy Balance Algorithm for Land (SEBAL) and Mapping Evapo Transpiration at high Resolution with Internalized Calibration (METRIC) algorithm to measure the net groundwater consumption during the market. In this regard, we evaluated the algorithms' performances using observed data from a local lysimeter. They are applied to the Nough plain in Iran to assess the effectiveness of the proposed market framework. The findings illustrate their efficiency in recovering approximately 80% (23.33 million cubic meters (MCM)) of groundwater loss due to overexploitation in the study area and increasing the users' annual benefits by 10.6% compared to the non-market condition. In addition, results imply that the METRIC model approximates daily crop ET with a higher accuracy level than the SEBAL model with RMSE, MAE, and Percentage Error of 0.37 mm/day, 0.32 mm/day, and 14.92%, respectively. This research revealed that the proposed market framework is a powerful tool for reallocating water entitlements and increasing water productivity in arid and semi-arid regions. • A groundwater market is proposed to promote economic and environmental situation. • The uncertainty of available water is incorporated in the proposed methodolgoy • Designed market mechanisms recover nearly 85% of groundwater loss in the study area. • The market framework raises the economic benefit by 128.7 billion rials annually. • METRIC algorithm approximates daily crop evapotranspiration with RMSE of 0.37 mm. [ABSTRACT FROM AUTHOR]

The observed and predicted changes in climate, as well as the growth in urban population, are creating severe stress on existing water resources in South Korea. By the importation of agricultural products from more water-rich countries through the virtual water concept, a country could save local water resources for other important uses. However, these imports from other countries could lead to certain vulnerabilities in the importing country derived from climate change. Therefore, through the application of the virtual water concept and the climate vulnerability index ((CVI) - measure of a country's vulnerability to indirect climate impacts), this study assessed the implication of virtual water imports and climate change through food trade, on the water, land and food security status of South Korea over the period of 2000–2017. The results showed that significant amounts of national water and land was saved through the importation of major upland crops. Virtual water imports increased significantly over time, rising from 16.2 Bm3 in 2000 to 16.5, 17.4, and 20.7 Bm3 in 2005, 2011, and 2017 respectively, with the USA, China, Australia, Brazil and Canada being the major exporters to South Korea. The study also revealed high CVI values for the oils and grains category of imported food, implying the high vulnerability of South Korea to climate change effects resulting from the import of these crops. The quantitative impacts and structural changes in virtual water trade, as well as the link between climate change, food security, international trade, and domestic water consumption could be evaluated for the sustainable management and allocation of resources. This study successfully identified and quantified the status of food trade and its environmental implications in the study area, providing insight into a better allocation of locally available resources. • South Korea's food trade is analyzed using the virtual water concept and climate vulnerability index. • Significant amounts of national water and land was saved through the importation of major upland crops. • Virtual water imports increased significantly between 2000 and 2017. • South Korea is more exposed to climate change effects from the imports of oils and grains. • The study can aid the development of effective policies that curb water stress. [ABSTRACT FROM AUTHOR]

Manure management is a major contributor to environmental impacts from large-scale dairy production. In this study, technologies for recovering energy, nutrients, and water from dairy manure were evaluated using life cycle assessment (LCA) and compared to conventional practices on California dairy farms. Six scenarios were evaluated: conventional manure management practices, anaerobic digestion (AD) for biogas recovery, and four scenarios for nutrients, energy, and water integrated recovery, called NEWIR. The NEWIR system consists of hydrothermal carbonization (HTC) for energy recovery via hydrochar, algae cultivation in the HTC aqueous product for nutrient recovery and production of protein-rich cattle feed, and water recovery from algae pond effluent via membrane distillation. Four NEWIR scenarios were evaluated, each with a different species of algae. Based on the results of the LCA, AD improves GHG emissions relative to conventional practices by 82%, but has similar eutrophication impacts, posing similar concerns for nutrient management as current practices. Results for the NEWIR system are highly dependent on the algae species used. Three of the four species evaluated (Chlamydomonas reinhardtii, Chlorella vulgaris, and Scenedesmus obliquus) improve GHG emissions by 420–500 kg CO 2 -eq. per functional unit, while net water consumption is increased by approximately 75% over AD and conventional practices Spirulina maxima requires more water and chemical inputs for cultivation than the other species, resulting in higher water use (21 times higher than baseline), though GHG emissions are still reduced by 85 kg CO 2 -eq. per functional unit relative to conventional practices. All NEWIR scenarios improve eutrophication impacts relative to AD and conventional practices by 16–46% for marine eutrophication and 18–99% for freshwater eutrophication, depending on the algae species used. The results suggest integrated resource recovery through NEWIR is a promising treatment method for manure to mitigate GHG emissions and improve nutrient management on large-scale farms. In addition, carbon and nutrient trading policies are discussed in relation to resource recovery technologies and their potential to incentivize producers to recover products from dairy manure. • Energy recovery with hydrothermal carbonization can reduce global warming potential. • Algae species affects environmental impacts due to changes in chemical requirements. • Integrated resource recovery improves multiple aspects of manure management. [ABSTRACT FROM AUTHOR]

Coffee consumption is concentrated in the "Global North", while production is mainly located in the "Global South". This trade-driven dependency leads to the exploitation of natural resources. As an export-oriented cash crop, such dependency jeopardizes the existence of a fair distribution of the risks and revenues among all the actors taking part in its globalized supply chain. Coffee trees are mainly rain-fed and only partly irrigated. However, the increasing global coffee demand led to higher consumption of freshwater, which can exacerbate the stressed condition of already stressed water basins. This study quantifies the impact of global coffee consumption on water scarcity, considering the larger system made of producer and consumer countries. The global displacement of such impact is driven by consumer preferences. We found that the US, EU and Asian countries' coffee consumption create impact on water scarcity mostly in African and South American countries, which is also representative of the economic disparities existing behind the global trade flows. Climate change will likely affect the varieties currently preferred by global consumers. Therefore, immediate environmental sustainability actions including water resource preservation are necessary to face current and future challenges. • Coffee production concentrates the required water consumption in few countries. • Coffee irrigation competes with other productions in water-scarce areas. • Worldwide coffee consumption drives the impact on water scarcity. • International trade can exacerbate or alleviate the impact of water consumption. • Sustainable trade and irrigation facilitate sustainable coffee consumption. [ABSTRACT FROM AUTHOR]

Land degradation is a global environmental problem that jeopardizes human safety and socioeconomic development. To alleviate severe soil erosion and desertification due to deforestation and overgrazing, China has implemented historically unprecedented large-scale afforestation. However, few studies have accounted for the resulting imbalance between water supply (primarily precipitation) and water consumption (evapotranspiration), which will affect ecosystem health and socioeconomic development. We compared the water balance results between restoration by means of afforestation and restoration using the potential natural vegetation to guide future ecological restoration planning and environmental policy development. Based on estimates of water consumption from seven evapotranspiration models, we discuss the consequences for water security using data obtained since 1952 under China's large-scale afforestation program. The models estimated that afforestation will increase water consumption by 559–2354 m 3 /ha annually compared with natural vegetation. Although afforestation is a potentially important approach for environmental restoration, China's current policy has not been tailored to local precipitation conditions, and will have therefore exacerbated water shortages and decrease the ability to achieve environmental policy goals. Our analysis shows how, both in China and around the world, future ecological restoration planning must account for the water balance to ensure effective and sustainable environmental restoration policy. [ABSTRACT FROM AUTHOR]

Cryptosporidium sp. and Giardia sp. are parasites that cause diseases in the population. Most of parasite diseases regarding the consumption of drinking water polluted with sewage are caused by Cryptosporidium sp. or Giardia sp. it is because of the incomplete disinfection of the wastewater treatment. Therefore, in this work the removal or inactivation efficiency of different treatment technologies presented by around 40 scientific studies was evaluated, with a view to water circularity. For Cryptosporidium sp., we conclude that the most efficient secondary technologies are aerobic technologies, which remove between 0.00 and 2.17 log units (Ulog), with activated sludge presenting the greatest efficiency, and that the tertiary technologies with the greatest removal are those that use ultrasound, which reach removal values of 3.17 Ulog. In the case of Giardia sp., the secondary technologies with the greatest removal are anaerobic technologies, with values between 0.00 and 3.80 Ulog, and the tertiary technologies with the greatest removal are those that combine filtration with UV or a chemical disinfection agent. Despite the removal values obtained, the greatest concern remains detecting and quantifying the infectious forms of both parasites in effluents; therefore, although the technologies perform adequately, discharge effluents must be monitored with more sensitive techniques, above all aiming for circularity of the treated water in a context of the water scarcity that affects some parts of the world. • Aerobic and ultrasound technologies present the greatest removal of Cryptosporidium sp. • Anaerobic technologies and combined disinfection present the greatest removal of Giardia sp. • Treated sewage presents concentration near to infective doses of Cryptosporidium sp. and Giardia sp. • To achieve circularity of treated sewage, exhaustive monitoring must quantify and measure the viability of Cryptosporidium sp. and Giardia sp. [ABSTRACT FROM AUTHOR]

Impact of heavy metal (HM) pollution and its understanding on environment as well as human beings has grown a lot during the last few decades. The goal of this study is to create a scientometric study on heavy metal contamination, in the period 1989 to 2020, in order to provide futuristic goals for the new researchers on wastewater treatment. For this, a search was conducted in the Web of Science (WoS) and Scopus databases, related to heavy metal pollution. Totally, 37,154 records were collected during the study period from 1989 to 2020. The findings revealed that China, the United States, and India has most referenced papers across a wide range of trans disciplinary issues such as toxicity, technology, and pollution. As a result, this study concludes that more research on various treatment methods is required in order to obtain high-quality water for consumption and routine activities, with the incorporation of various treatment tasks poses various challenges for the upcoming future studies. [Display omitted] • A bibliometric study is performed an heavy metal pollution between 1989 and 2020. • 37,154 records were critically analyzed to extract the bibliographic maps. • China, USA and India are the leading countries in heavy metal pollution research. • Advanced oxidation, coagulation-flocculation, adsorption, and membrane filtering technologies were focussed. [ABSTRACT FROM AUTHOR]

As the total water resources consumption control and carbon mitigation continuous improvement, the weak water-carbon incorporate management is increasingly exposed. In this study, a water-carbon nexus assessment framework is proposed to analyze the nexus relationship between water consumption and carbon emission, and distinguishes the coupled water-carbon transmission intensity and the transfer paths under regional and industrial scales. According to the practical input-output table, water consumption, and carbon emission information, the framework is applied to Beijing-Tianjin-Hebei urban agglomeration (BTHUA), a population, resource, and trade intensive area of China. Inter-regional/intra-regional water consumption and carbon emission transfer fluxes between sectors, the pairwise ecological relationship, and the water-carbon nexus were analyzed. Results indicated that the water-carbon transfer indexes from Hebei to Beijing and Tianjin were 161.85 kg/m3 and 113.88 kg/m3 in the study period, along with the most water consumption and carbon emission, and the worst water-carbon nexus. From the industrial perspective, electricity and gas supplying industry provided 7.8% and 29.1% of the total carbon transfer in Tianjin and Hebei, as the most key node sectors on the water-carbon nexus in the BTHUA. The research provides valuably supporting the adjustment of the existing urban agglomeration water-carbon nexus management schemes. • A new assessment framework was developed to analyze water-carbon nexus among regions/industries. • Water-carbon nexus among provinces and sectors was accounted in urban agglomeration. • It can identify key region/sectors for dual goals of water saving and carbon emission reduction. • Electricity and Gas Supplying was the most key node sector on the water-carbon nexus. [ABSTRACT FROM AUTHOR]

Water shortage, increased demand and rising energy costs are major challenges for the water sector worldwide. Here we use a comparative case study to explore the long-term changes in the system-wide water and associated energy use in two different regions that encountered water shortage. In Australia, South East Queensland (SEQ) encountered a drought from 2001 to 2009, while Perth has experienced a decline in rainfall since the 1970s. This novel longitudinal study quantifies and compares the urban water consumption and the energy use of the water supply systems in SEQ and Perth during the period 2002 to 2014. Unlike hypothetical and long-term scenario studies, this comparative study quantifies actual changes in regional water consumption and associated energy, and explores the lessons learned from the two regions. In 2002, Perth had a similar per capita water consumption rate to SEQ and 48% higher per capita energy use in the water supply system. From 2002 to 2014, a strong effort of water conservation can be seen in SEQ during the drought, while Perth has been increasingly relying on seawater desalination. By 2014, even though the drought in SEQ had ended and the drying climate in Perth was continuing, the per capita water consumption in SEQ (266 L/p/d) was still 28% lower than that of Perth (368 L/p/d), while the per capita energy use in Perth (247 kWh/p/yr) had increased to almost five times that of SEQ (53 kWh/p/yr). This comparative study shows that within one decade, major changes in water and associated energy use occurred in regions that were similar historically. The very different “water-energy” trajectories in the two regions arose partly due to the type of water management options implemented, particularly the different emphasis on supply versus demand side management. This study also highlights the significant energy saving benefit of water conservation strategies (i.e. in SEQ, the energy saving was sufficient to offset the total energy use for seawater desalination and water recycling during the period.). The water-energy trajectory diagram provides a new way to illustrate and compare longitudinal water consumption and associated energy use within and between cities. [ABSTRACT FROM AUTHOR]

This article discusses the mapping of opportunities for the water reuse in a cascade based system in a petrochemical industry in southern Brazil. This industrial sector has a large demand for water for its operation. In the studied industry, for example, approximately 24 million cubic meters of water were collected directly from the source in 2014. The objective of this study was to evaluate the implementation of the reuse of water in cascade in a petrochemical industry, focusing on the reuse of aqueous streams to replenish losses in the cooling towers. This is an industrial scale case study with real data collected during the years 2014 and 2015. Water reuse was performed using heuristic approach based on the exploitation of knowledge acquired during the search process. The methodology of work consisted of the construction of a process map identifying the stages of production and water consumption, as well as the characterization of the aqueous streams involved in the process. For the application of the industrial water reuse as cooling water, mass balances were carried out considering the maximum concentration levels of turbidity, pH, conductivity, alkalinity, calcium hardness, chlorides, sulfates, silica, chemical oxygen demand and suspended solids as parameters turbidity, pH, conductivity, alkalinity, calcium hardness, chlorides, sulfates, silica, chemical oxygen demand and suspended solids as parameters. The adopted guideline was the fulfillment of the water quality criteria for each application in the industrial process. The study showed the feasibility for the reuse of internal streams as makeup water in cooling towers, and the implementation of the reuse presented in this paper totaled savings of 385,440 m 3 /year of water, which means a sufficient volume to supply 6350 inhabitants for a period of one year, considering the average water consumption per capita in Brazil; in addition to 201,480 m 3 /year of wastewater that would no longer be generated. [ABSTRACT FROM AUTHOR]

The quality of a drinking water source depends largely on upstream contaminant discharges. Sewer overflows can have a large influence on downstream drinking water intakes as they discharge untreated or partially treated wastewaters that may be contaminated with pathogens. This study focuses on the quantification of Escherichia coli discharges from combined sewer overflows (CSOs) and the dispersion and diffusion in receiving waters in order to prioritize actions for source water protection. E. coli concentrations from CSOs were estimated from monitoring data at a series of overflow structures and then applied to the 42 active overflow structures between 2009 and 2012 using a simple relationship based upon the population within the drainage network. From these estimates, a transport-dispersion model was calibrated with data from a monitoring program from both overflow structures and downstream drinking water intakes. The model was validated with 15 extreme events such as a large number of overflows (n > 8) or high concentrations at drinking water intakes. Model results demonstrated the importance of the cumulative effects of CSOs on the degradation of water quality downstream. However, permits are typically issued on a discharge point basis and do not consider cumulative effects. Source water protection plans must consider the cumulative effects of discharges and their concentrations because the simultaneous discharge of multiple overflows can lead to elevated E. coli concentrations at a drinking water intake. In addition, some CSOs have a disproportionate impact on peak concentrations at drinking water intakes. As such, it is recommended that the management of CSOs move away from frequency based permitting at the discharge point to focus on the development of comprehensive strategies to reduce cumulative and peak discharges from CSOs upstream of drinking water intakes. [ABSTRACT FROM AUTHOR]

Some methods to design water networks with minimum fresh water consumption are based on the selection of a key contaminant. In most of these “single contaminant methods”, a maximum allowable concentration of contaminants must be established in water demands and water sources. Turbidity is not a contaminant concentration but is a property that represents the “sum” of other contaminants, with the advantage that it can be cheaper and easily measured than biological oxygen demand, chemical oxygen demand, suspended solids, dissolved solids, among others. The objective of this paper is to demonstrate that turbidity can be used directly in the design of water networks just like any other contaminant concentration. A mathematical demonstration is presented and in order to validate the mathematical results, the design of a water network for a guava fudge production process is performed. The material recovery pinch diagram and nearest neighbors algorithm were used for the design of the water network. Nevertheless, this water network could be designed using other single contaminant methodologies. The maximum error between the expected and the real turbidity values in the water network was 3.3%. These results corroborate the usefulness of turbidity in the design of water networks. [ABSTRACT FROM AUTHOR]

Water scarcity and water pollution problems are becoming increasingly serious in many regions of the world due to rapid socioeconomic development. Water resources environmental carrying capacity (WRECC), which embodies the attributes of social, economic, resource and environmental aspects, is usually considered as a significant metric to guide regional sustainable development. Most existing studies on WRECC mainly focus on conceptual discussions and evaluation methods, lacking a systematic insight into the theoretical connotations of WRECC and neglecting the interaction mechanisms within the WRECC system. Therefore, this study aims to propose a new WRECC evaluation method based on support and pressure theory to deeply reveal the state change and driving mechanisms of WRECC. Firstly, a WRECC evaluation system incorporating support and pressure is constructed and the WRECC performance is determined by both the support index and pressure index. Subsequently, the catastrophe progression method and the obstacle degree model are introduced to quantify the WRECC and identify the primary influencing factors. Lastly, the feasibility and validity of this methodology are verified through an empirical application in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA). The results indicate that the WRECC of the GBA presents an upward trend from 2010 to 2019, shifting from a low-value load state to a low-value surplus state. Moreover, the WRECC performance varies significantly among cities in the GBA, especially for edge cities that generally exhibit higher support, pressure and WRECC indices than central cities. In addition, common obstacles that affect WRECC are total water resources, water resources per capita, water consumption per hectare for agriculture and proportion of the tertiary industry. Furthermore, this study reveals that the coupling relationship between support and pressure develops towards a positive direction, and water environment protection and economic development are the main drivers of WRECC development. This new proposed methodology can provide a theoretical reference for investigating regional WRECC and formulating appropriate sustainable development strategies. [Display omitted] • A new method to WRECC research based on support and pressure theory is proposed. • The concept of support and pressure is used to establish the WRECC evaluation system. • The applicability and validity of this method are verified by the study of the GBA. • Obstacle factors and driving mechanisms of WRECC development in the GBA are analyzed. • This study provides an accurate insight for in-depth understanding of the WRECC. [ABSTRACT FROM AUTHOR]

Human activities cause widespread changes in landscape composition, which can affect ecosystem services produced by these landscapes. It is usually believed that ecosystem services can be maximized only when we eliminate all human activities. However, this belief is not the case, at least in dryland ecosystems. Here, a gradient of human activity intensity was used to investigate changes in the value of ecosystem services over 30-years of land-use change between 1990 and 2020 in the arid Sangong River watershed of northwest China. Spatial analyses were performed to determine how the value of dryland ecosystem services changed with human activity intensity. Stepwise regressions and linear programming models were also performed to examine how to optimize the value of ecosystem services (i.e., regulating services, provisioning services, supporting services, and cultural services). We found that landscapes of the Sangong River watershed became increasingly fragmented and that human activities gradually intensified, but the value of ecosystem services fluctuated rather than linearly decreasing over the past 30 years. Specifically, a unimodal relationship was observed between human activities and ecosystem services. The peak value of ecosystem services was 5799 USD ha−1 yr−1 under intermediate human activity intensity (i.e., human footprint index ranged from 0.2 to 0.4 at a scale of one). Gross domestic product (GDP) per capita, population, and water consumption were the three most important driving factors of human activities and ecosystem services. Our results suggest that intermediate human activities may maximize dryland ecosystem services in long-term land-use change at the watershed scale, and highlight the importance of regulating economic development, population, and water consumption for the management of dryland ecosystem services. [Display omitted] • Eliminating all human activities does not always maximize ecosystem services. • Human activities contribute to landscape fragmentation at the watershed scale. • Human activities are non-linearly associated with dryland ecosystem services. • There are synergies and trade-offs among various ecosystem services. [ABSTRACT FROM AUTHOR]

Biodrying is a promising method that produces bio-stabilized output with minimum pretreatment requirements. In this study, a hot-air supply system was added to the traditional biodrying process for kitchen waste, which showed significant reduction in moisture content in 5 days (maximum reduction of 37.45%). A series of experiments was conducted to optimize the hot-air biodrying system utilizing different aeration rates, temperatures, and mixing ratios of feedstock to bulking agents. The results showed that a 65 °C aeration temperature led to the highest water removal rate and low volatile solids consumption rate, with the biodrying index reaching 4.9 g water per gram of volatile solids. On the other hand, evaluation of the overall biodrying efficiency based on the weight loss and bio-stabilization showed that intermittent aeration temperature at 55 °C performed best, offering suitable conditions for water evaporation and bio-degradation. In combination with a flow rate of 0.8 L/kg*min and 1:1 mixing ratio, these conditions resulted in the maximum volatile solids consumption of 26.26% in 5 days. The volatile solids consumption and 34.47% water removal rate of the trial had contributed to a total of 64.13% weight loss. The weight loss was even higher than that of a conventional biodrying system which was conducted for more than 14 days. • A hot-air aeration system was developed based on traditional biodrying techniques. • The hot-air biodrying improves working efficiency compared with thermal drying. • The hot-air biodrying is affected by aeration rate, temperature, and mixing ratio. • The new biodrying system could be optimized with 0.8 L/kg*min, 55 °C, and 1:1 feedstock: bulking. [ABSTRACT FROM AUTHOR]