Exploring interactions between factors is a critical step to understand, quantify and govern the WEF-Nexus. However, current research mainly focuses on mapping causal loops and the hierarchy structure; equations in interaction exploration have been largely ignored. Using the panel data of China’s 30 provinces from 2005 to 2016, this paper adopts a simultaneous equations model (SEM) to evaluate intensities between related factors in the local WEF-Nexus. We define a local WEF-Nexus as containing core, peripheral and interactive sub-nexuses, and decouple the core sub-nexus from the supply, consumption and waste disposal processes. Results show that effective irrigated area, secondary industry rate and crop sown area are key positive influencing factors in the WEF subsystem, with positive impact coefficients of 1.0426, 0.6986 and 1.149, respectively. Food production (-0.303) and chemical fertilizer used per sown area unit (-0.3129) are key negative factors in the WEF subsystem. Additionally, urban green land (0.4436) and total population (0.5815) exert specific influences on the water and energy subsystems, with a 1% increase in urban green land resulting in a 0.4436% increase in water consumption. The system boundary, two positive feedback loops and seven nexus points are identified, with total groundwater pumping being the only nexus point exerting an holistic impact across the WEF equations. The results in this paper complement recent nexus modeling work, and give a better understand of interaction mechanism in China’s local WEF nexus, with useful implications for future policy development.

This article addresses food-energy-water-waste nexus optimization to alleviate the public health and environmental concerns from increasing food waste generation during the COVID-19 pandemic using waste-to-energy technologies. Food waste increase has become a severe global problem during the pandemic. It could alleviate health and environmental concerns by converting the food waste into electricity and heat through food-energy-water-waste nexus systems using waste-to-energy facilities, such as anaerobic digesters and combined heat and power units in wastewater treatment plants. To design efficient nexus systems, a multi-period multi-objective optimization model is proposed, while considering various impacts of the pandemic. A case study for New York State is presented. The optimized systems show a potential of reducing the food waste disposal amounts by 38%. The Pareto-optimal solutions illustrate a clear trade-off between the objectives. The minimum total cost is $27.1 million; the optimal unit processing profit is $11.9 per ton processed food waste. Spatial analyses reveal a clear correlation between facility selections and their processing capacities. Electricity price and biogas yield are the most important factors for the economic objectives, based on sensitivity analysis.

Micronized grape skin powder (GS) and maltodextrin-encapsulated grape skin phenolics (eGSP) were recovered from winemaking byproducts as potential food ingredients. Hygroscopicity was higher in eGSP than in GS. Both eGSP and GS had intense color and less fermented odor than the wet GS. Phenolic content, antioxidant activity and inhibitory effectiveness towards enzymes related to hyperglycemia damage were ~ double in eGSP than in GS. During storage, the rate of phenolic degradation diminished with decreasing aw from 0.75 to 0.11. Anthocyanins and proanthocyanidins were less stable than monomeric flavanols and flavonols. The rate of decrease in antioxidant activity was lower compared to the extent of phenolic degradation. At aw 0.11 no degradation was observed in eGSP, while anthocyanin and proanthocyanidin contents slightly decreased in GS (k∗103 in the range 0.69–2.94d−1). Criteria for GS and eGSP storage were defined in relation to their final uses.The conversion of winemaking by products into value added products is considered the unique strategy to overcome the cost of not recycling, including waste disposal and decontamination of affected areas. As winemaking is a seasonal activity, long-term stability of recovered byproducts is needed for their further utilization. GS and eGSP represent potential value-added food ingredients for wide-ranging applications (antioxidant, colorant, phenolic sources) and tailor-made functionalities (inhibitors of enzymes related to hyperglycemia). The results obtained led to the definition of criteria for GS and eGSP storage, which depend on their final use in foods, as illustrated by two discussed scenarios.