This study investigated the enhancement effect of N₂- and Air-nanobubble water (NBW) supplementation on two-stage anaerobic digestion (AD) of food waste (FW) for separate production of hydrogen and methane. In the first stage for hydrogen production, the highest cumulative H₂ yield (27.31 ± 1.21 mL/g-VSₐddₑd) was obtained from FW + Air-NBW, increasing by 38% compared to the control (FW + deionized water (DW)). In the second stage for methane production, the cumulative CH₄ yield followed a descending order of FW + Air-NBW (373.63 ± 3.58 mL/g-VSₐddₑd) > FW + N₂-NBW (347.63 ± 7.05 mL/g-VSₐddₑd) > FW + DW (300.93 ± 3.24 mL/g-VSₐddₑd, control), increasing by 24% in FW + Air-NBW and 16% in FW + N₂-NBW compared to the control, respectively. Further investigations indicate that different gas–NBW may positively impact the different stages of AD process. Addition of N₂-NBW only enhanced the hydrolysis/acidification of FW with no significant effect on methanogenesis. By comparison, addition of Air-NBW promoted both hydrolysis/acidification stage and methanogenesis stage, reflecting by the enhanced activities of four extracellular hydrolases at the end of hydrolysis/acidification and coenzyme F₄₂₀ at the end of methanogenesis, respectively. Results from this work suggest the potential application of Air-NBW in the two-stage AD for efficient renewable energy recovery from FW.

In this work, we present a low-field magnetic resonance imaging (LF-MRI) aptasensor based on the difference in magnetic behavior of two magnetic nanoparticles with diameters of 10 (MN₁₀) and 400 nm (MN₄₀₀) for the rapid detection of Pseudomonas aeruginosa (P. aeruginosa). First, specific anti-P. aeruginosa aptamers were covalently immobilized onto magnetic nanoparticles via 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide chemistry for the capture of the target bacteria. In the presence of P. aeruginosa, an MN₁₀–bacteria–MN₄₀₀ (MBM) complex was formed after binding between the aptamers on magnetic nanoparticles and P. aeruginosa cells. When a magnetic field was applied, the MBM complex and free MN₄₀₀ were rapidly magnetically separated, and free MN₁₀ left in the solution worked as a T₂ (transverse relaxation time) single readout in MRI measurement. Under optimum conditions, the LF-MRI platform provides both image analysis and quantitative detection of P. aeruginosa, with a detection limit of 100 cfu/mL. The feasibility and specificity of the aptasensor were demonstrated in detecting real food, orange juice, and drinking water samples and validated using plate counting methods.

A copula-based stochastic fractional programming (CSFP) method is developed for optimizing water-food-energy nexus (WFEN) system, which can tackle random variables under conflicting objectives and analyze the interrelationship between marginal benefit and system-failure risk. Then, a CSFP-WFEN model is formulated for the Aral Sea basin and multiple scenarios with individual- and joint-probabilistic risks related to water resources, arable land, and hydropower generation are examined. Synthesizing the results under all scenarios, hydropower generation would decrease by 11.9% and crop area would increase by 12.4% by 2035 under severe water scarcity. Agricultural water would decrease with time (from 69.1% in 2021 to 53.9% in 2035), and the share of wheat farmland would increase by 16.4% for food security. Compared with the traditional stochastic fractional programming (SFP) and copula-based stochastic programming (CSP) methods, the marginal benefit from CSFP would be improved 1.7% and water would be saved 9.2%. To support sustainable development of the study basin, some suggestions can be derived from the results: (i) since agriculture is still the largest water user in the future, it is desired to reduce its water consumption through improving irrigation efficiency and adjusting crop planting structure; (ii) effectively reducing Uzbekistan’s water consumption can improve water allocations to other countries and relieve regional conflicts caused by water shortage; (iii) compared to the single management pattern, the integrated optimization of water, food and energy nexus not only has higher efficiency of resources allocation and utilization, but also allows an increased robustness in controlling system-failure risk under joint probabilistic constraints.

Food gels prepared from the water extract of fish scales (WEFS) are described in this study. The effects of WEFS, sucrose, and NaCl concentration on gel formation and stability, gel texture, and gel sensory attributes were evaluated. The results indicated that an increase in WEFS concentration led to increases in the formation rate, stability, and texture of the gel. Addition of a moderate amount of sucrose (2%–3%, w/v) and NaCl (0.4%–0.6%, w/v) improved the stability, gumminess, chewiness, and cohesiveness of the gel. However, the addition of an excessive amount of sucrose (>4%, w/v) and NaCl (>0.8%, w/v) decreased the stability, gel strength, adhesiveness, and springiness of the gel. The sensory attributes of fish scales (FS) gels were mainly affected by WEFS concentration. On the basis of combined textural analysis and sensory evaluation, the FS gels formed with 4% WEFS, 3% sucrose, or 0.4% NaCl was proposed in this study. The gel microstructure and water distribution obviously showed an apparent variation, together with a change in the structure of FS gels. Competing hydrophilic forces and electrostatic interactions varied with sucrose and NaCl concentration, altering the structure and water distribution of FS gels.

In the context of climate change mitigation and adaptation, the concept of the water-energy-food nexus (WEF nexus) has resulted in an increased focus on the long-neglected potential trade-offs between the water, energy, and food sector. In this study, we obtained 3077 publications from the Science Citation Index Expanded (SCIE) and the Social Sciences Citation Index (SSCI) in the Web of Science. A bibliometric method was used to characterize the publications, the participating countries, and the research trends in the field of the WEF nexus. The results show (i) the number of scientific publications increased exponentially from 2011 to June 2019, with an average annual growth rate of 27.87%. (ii) The Journal of Geophysical Research: Atmospheres had the most publications related to WEF nexus research. (iii) Environmental Sciences Ecology was the subject category with the most publications. (iv) WEF nexus research was led by the USA, which produced 40.14% of the publications in this field, and five of the ten most influential institutions are American institutions. (v) China ranked in second place regarding publication volume and exceeded the UK in 2016 in annual publications. The Chinese Academy of Sciences was the most productive research institution. (vi) Academic collaboration between countries was widespread in the WEF nexus field; the top 10 most productive countries all had high proportions of collaborative publications (> 40%), and Austria had the highest percentage (91.49%). (vi) Co-word analysis indicated that the term map had three clusters in 1988–2011 focusing on biological production, climate and meteorology, and land surface research. In 2012–2019, the term map also had three clusters, including experimental research on recyclables, resource management, and land-atmosphere interactions. Frequency analysis of the keywords in different countries showed different research emphases in the top 10 most productive countries. The analyses of frequently used keywords also revealed the research hotspots and trends. “Climate change” was the second most frequently used keyword in these countries. The interpretation of climate change mitigation and adoption strategies from the WEF nexus perspective is an important research direction.

Crop planting provided foods, generated incomes, and consumed water resources to different extents under different spatiotemporal agroclimatic conditions. For balancing three aspects, targeting the rice, maize, wheat, and sorghum planted in Liaoning during the recent two decades, we established an integrated research framework consisting of water footprint (WF) accounting, clustering analysis, and fuzzy optimization programming to quantify the temporal trends and spatial distribution of water footprints, and optimized the planting structure under the different spatiotemporal agroclimatic conditions. Results showed that the maximum water footprint differences were 4166.73 m³/t and 4790.71 m³/t in spatial distribution and temporal series, respectively. Based on precipitation, we established 12 agroclimatic scenarios according to K-Means clustering. The fuzzy optimization result indicated that the planting area percent ranges of maize, wheat, rice, and sorghum in Liaoning province were 4.96%–98.62%, 0.00%–8.55%, 0.00%–18.18%, and 0.00%–95.04%, respectively under the different spatiotemporal conditions. This study's methods and results help make targeted decisions related to grain planting structure while considering the complex spatial-temporal conditions.

Food, energy, and water (FEW) resources are critical concerns to achieve long-term sustainability. Climate change and socio-economic development both affect the FEW Nexus, but the combined impacts of these two factors on a Nexus system is not well understood. An integrated management model was applied to quantify the combined impacts on the FEW Nexus through rice yield, power generation, and water withdrawal. Five scenarios from the Coupled Model Intercomparison Project Phase 6 were chosen as the inputs of the integrated model in the Mekong River Delta (MRD). Results showed that rice yields will be vulnerable to extreme climate events. The minimum autumn rice yield, 4.7 ton/ha in 2023 under the SSP1–2.6 scenario, will be as low as the yield of the 2016 drought year (4.6 ton/ha). Power generation will increase sharply due to socio-economic development. The power generation of SSP5–8.5 in 2050 will be about 10 times higher than that in 2010. The average total water withdrawal in 2050 was estimated to increase by 40% compared to that in the 2016 drought year and will be more than 3 times higher than the average withdrawal of 1995–2010. Nexus analysis found water is a central resource that connects food and energy sectors in MRD. Regional sustainability analysis showed that climate change and socio-economic development both have a significant impact through affecting the FEW Nexus. Specifically, the energy and water sectors will be more vulnerable to the combined impacts than the food sector due to the coal-fired power plants planned in the MRD.

Interventions of water harvesting technologies (WHTs) in drought-prone areas like the Tigray region (northern Ethiopia) is an option less strategy to alleviate food insecurity issues emanating from water scarcity. Hence, wide spectrums of WHTs were applied in Tigray Region in the last three decades. Thus, this study aimed to assess the WHTs and the subsequent contributions in ensuring households’ food security in Kilete-Awlaelo district of the Tigray Region. Quantitative and qualitative data were collected through a household survey (n = 246), focus group discussion, key informants interview, and field observation, and subjected to descriptive and inferential statistical analysis on the SPSS environment. The explanatory power of the WHTs to food security was determined using a regression model. The result revealed that 64.6% of the households applied WHTs while 35.4% not. Though a statistically significant positive relationship (p < 0.05) between the WHTs (predictor) and PCC acquisition as food security parameter (predictand) was observed, the magnitude was not strong enough where only 6.1% of WHTs users and 0.81% of non-users had achieved the average standard PCC requirement (2100 kcal) from their farm production. Hence, strengthening and expanding the functional domain of the WHTs fitting to the socio-economic, environmental, and biophysical context of the locality is profoundly indispensable.

The Nile is the lifeblood of northeastern Africa, and its roles for and interdependency with the national economies it traverses and binds together grow as it moves from source to sea. With rapid economic development—population growth, irrigation development, rural electrification, and overall economic growth—pressures on the Nile’s water resources are growing to unprecedented levels. These drivers of change have already contributed to stark changes in the hydropolitical regime, and new forms of cooperation and cross-sectoral collaboration are needed, particularly in the Eastern Nile Basin countries of Egypt, Ethiopia, Sudan, and South Sudan. As direct sharing of water resources is hampered by unilateral developments, the need has increased for broader, cross-sectoral collaboration around the water, energy, and food sectors. This study is conducted to assess and understand the challenges of and opportunities for cooperation across the water-energy-food nexus nationally in Egypt, Ethiopia, and Sudan, as well as regionally across the Eastern Nile. To gather data, the paper uses an e-survey supplemented with key informant interviews geared toward national-level water, energy, and agriculture stakeholders, chiefly government staff and researchers. Findings from the survey tools suggest that most respondents strongly agree that collaboration across the water, energy, and agriculture sectors is essential to improve resource management in the region. At the same time, there is ample scope for improvement in collaboration across the water, energy, and food sectors nationally. Ministries of water, energy, and food were identified as the key nexus actors at national levels; these would also need to be engaged in regional cross-sectoral collaboration. Respondents also identified a wide range of desirable cross-sectoral actions and investments—both national and regional—chiefly, joint planning and operation of multipurpose infrastructure; investment in enhanced irrigation efficiency; joint rehabilitation of upstream catchments to reduce sedimentation and degradation; and investment in alternative renewable energy projects, such as wind and solar energy. | Non-PR | IFPRI1; CRP5; E Building Resilience | EPTD; DSGD | CGIAR Research Program on Water, Land and Ecosystems (WLE)

Commonalities and asynchronous experiences of realizing zero-waste of water, energy, and food resources between the world and China have critical global importance to support sustainable development, especially for Guangdong-Hong Kong-Macao Greater Bay Area (GBA) urban agglomeration. In this study, a comprehensive assessment framework for the zero-waste city was proposed to evaluate zero-waste construction in the world (e.g., San Francisco, New York, and Tokyo) and China (e.g., Beijing, Shanghai, and GBA) from the perspective of water, energy, and food. The results showed that the zero-waste construction level of the GBA cities was weaker than that of the benchmark city and other world-class cities. The average score of the GBA cities was the lowest, 2.5% lower than the benchmark city and 11.8% lower than other world-class cities. Macao had apparent advantages in the social-economic and ecological-environment system, while the Pearl River Delta cities were considerably better than Macao and Hong Kong in the water and food systems. Future work could improve the level of zero-waste construction by learning from foreign zero-waste cities’ advanced experience, increasing efforts to promote the implementation of a circular economy, and building an all-around government sharing mechanism with public participation.