Throughout the world, much food produced is wasted. The resource impact of producing wasted food is substantial; however, little is known about the energy and water consumed in managing food waste after it has been disposed. Herein, we characterize food waste within the Food-Energy-Water (FEW) nexus and parse the differential FEW effects of producing uneaten food and managing food loss and waste. We find that various food waste management options, such as waste prevention, landfilling, composting, anaerobic digestion, and incineration, present variable pathways for FEW impacts and opportunities. Furthermore, comprehensive sustainable management of food waste will involve varied mechanisms and actors at multiple levels of governance and at the level of individual consumers. To address the complex food waste problem, we therefore propose a “food-waste-systems” approach to optimize resources within the FEW nexus. Such a framework may be applied to devise strategies that, for instance, minimize the amount of edible food that is wasted, foster efficient use of energy and water in the food production process, and simultaneously reduce pollution externalities and create opportunities from recycled energy and nutrients. Characterization of FEW nexus impacts of wasted food, including descriptions of dynamic feedback behaviors, presents a significant research gap and a priority for future work. Large-scale decision making requires more complete understanding of food waste and its management within the FEW nexus, particularly regarding post-disposal impacts related to water.

In this paper, we have explored the possibility of substituting traditional meat products with an alternative source of protein (insects) in order to reduce human pressure on water. Insects, in fact, could represent a good alternative source of quality proteins and nutrients and they are already a very popular component of the diet of one third of the world’s population in approximately 80% of countries. In the study, we have taken into account only two species of edible insects (Tenebrio molitor and Zophobas morio mealworms), because they are already commercially produced even in Western countries, and for this reason it is possible to find specific data in literature about their diets. We have used the water footprint (WF) as a reliable indicator to calculate the volume of water required for production and to compare different products. The final aim of the work is, in fact, to evaluate the WF of the production of edible insects with a focus on water consumption associated with protein content, in order to make a comparison with other animal protein sources. We have demonstrated that, from a freshwater resource perspective, it is more efficient to obtain protein through mealworms rather than other traditional farmed animals.

This research study shows that ‘business-as-usual’ scenarios will have substantial production surpluses of rice, which dominates water use patterns in the country at present. However, the surpluses come at a considerable environmental cost, due to high levels of groundwater depletion. Bangladesh can mitigate potential groundwater crises by limiting rice production to meet the requirements of self-sufficiency. Increases in water productivity of both Aman (wet season) and Boro (dry season) rice production can help too. A carefully designed deficit irrigation regime for Boro rice can also increase transpiration, yield, water productivity and production, and reduce the pressure on scarce groundwater resources.

This research study shows that ‘business-as-usual’ scenarios will have substantial production surpluses of rice, which dominates water use patterns in the country at present. However, the surpluses come at a considerable environmental cost, due to high levels of groundwater depletion. Bangladesh can mitigate potential groundwater crises by limiting rice production to meet the requirements of self-sufficiency. Increases in water productivity of both Aman (wet season) and Boro (dry season) rice production can help too. A carefully designed deficit irrigation regime for Boro rice can also increase transpiration, yield, water productivity and production, and reduce the pressure on scarce groundwater resources.

Evaluations of food, energy and water (FEW) linkages are rapidly emerging in contemporary nexus studies. This paper demonstrates, from a food consumption perspective, the potential of life cycle thinking in understanding the complex and often “hidden” linkages between FEW systems. Our study evaluates the upstream virtual water and embodied energy in food consumption in the Tamar catchment, South West England, distinguishing between domestic production and imports origin. The study also evaluates key inputs, including virtual nutrients and animal feed, when tracking supply chain of food products. Based on current dietary patterns and food products selection, the catchment consumes annually 834 TJ, 17 hm³ and 244 hm³ of energy, blue water and green water, respectively. Tamar is not self-sufficient in terms of food and requires imports of food products, as well as imports of virtual nutrients and animal feed for local production. Consequently, 51% of the embodied energy and 88% blue and 45% green virtual water in food consumed within the catchment are imported. Most of the embodied energy (58%) and green virtual water (90%) are because of animal feed production, where nearly half of embodied energy (48%) and green virtual water (42%) come from imports. 92% of blue virtual water is used for irrigation and primarily happens elsewhere due to imports. Irrigation is the process that demands the largest amount of energy for the crop-based products, with 38% of their total energy demand, followed by fertilisers production (24%). Our study illustrates water and energy hotspots in the food life cycle and highlights potential FEW risks and trade-offs through trade. This is useful considering potential unexpected changes in trade under recent global socio-political trends. Currently available databases and software make LCA a key tool for integrated FEW nexus assessments.

Many countries are exposed to malnutrition within their population, either in the form of undernutrition or obesity leading to dire affects for human health. As a consequence, a ‘Decade of Action’ was certified by the UN in 2016 to promote the need to end all types of malnutrition. Within food security objectives, this study evaluates the possibility to maximise the nutritional value of agricultural output through the optimal allocation of water and energy resources. Using a hypothetical case study in Qatar, two complementary multi-objective mathematical models are developed to solve various scenarios. Firstly, the goal programming minimises the expected value of negative deviation from the desired target in food groups and nutrients. Secondly, the linear programming model increases the expected value of self-sufficiency percentage in food groups and nutrients. The results indicate the specific dependency of increasing the self-sufficiency of different nutrients on the increased production of dates group and fish group, implying that dates and fish can be considered strategic crops in terms of their contribution towards food security, owing to the fact that they require the least quantity of water and energy resources for production. As poultry and meat groups require the largest quantities of water and energy resources, optimal results do not favour their production. The optimal production mix that increases the satisfaction of nutrients at 40% of the food groups self-sufficiency satisfaction with the same amount of energy and water are as follows: 52378, 47085, 111303 tonnes of dates, milk and dairy products and fish groups respectively. This production mix will achieve 29.18%, 100%, 90.8%, and 2.5% satisfaction percentage of carbohydrates, protein, fats, and fibres respectively.

Efficient use of water and nutrients in crop production are critical for sustainable water and crop production systems. Understanding the role of humans in ensuring water and nutrient use efficiency is therefore an important ingredient of sustainable development. Crop production functions are often defined either as functions of water and nutrient deficiency or are based on economic production theory that conceptualizes production as a result of economic activities that take in inputs such as water, capital and labor and produce crop biomass as output. This paper fills a gap by consistently treating water and nutrient use and human agency in crop production, thus providing a better understanding of the role humans play in crop production. Uptake of water and nutrients are two dominant biophysical processes of crop growth while human agency, including irrigation machine power, land-preparing machine power and human labor force, determine limits of water and nutrient resources that are accessible to crops. Two crops, i.e., winter wheat and rice, which account for the majority of food crop production are considered in a rapidly developing region of the world, Jiangsu Province, China, that is witnessing the phenomenon of rural to urban migration. Its production is modeled in two steps. First water and nutrient efficiencies, defined as the ratios of observed uptake to quantities applied, are modeled as functions of labor and machine power (representing human agency). In the second step, crop yields are modeled as functions of water and nutrient efficiencies multiplied by amounts of water and fertilizers applied. As a result, crop production is predicted by first simulating water and nutrient uptake efficiencies and then determining yield as a function of water and nutrients that are actually taken up by crops. Results show that modeled relationship between water use efficiency and human agency explains 68% of observed variance for wheat and 49% for rice. The modeled relationship between nutrient use efficiency and human agency explains 49% of the variance for wheat and 56% for rice. The modeled relationships between yields and actual uptakes in the second step explain even higher percentages of observed the variance: 73% for wheat and 84% for rice. Leave-one-out cross validation of yield predictions shows that relative errors are on average within 5% of the observed yields, reinforcing the robustness of the estimated relationship and of conceptualizing crop production as a composite function of bio-physical mechanism and human agency. Interpretations based on the model reveal that after 2005, mechanization gradually led to less labor being used relative to machinery to achieve same levels of water use efficiency. Labor and irrigation equipment, on the other hand, were found to be complimentary inputs to water use efficiency. While the results suggest interventions targeting machinery are most instrumental in increasing wheat productivity, they may exasperate rural – urban migration. Policy strategies for alleviating rural-urban migration while ensuring regional food security can nonetheless be devised where appropriate data are available.

Food production is a source of various pollutants in aquatic systems. For example, nutrients are lost from fertilized fields, and pathogens from livestock production. Water pollution may impact society and nature. Large-scale water pollution assessments, however, often focus on single pollutants and not on multiple pollutants simultaneously. This study draws lessons from air pollution control for large-scale water quality assessments, where multi-pollutant approaches are more common. To this end, we present a framework for future water pollution assessments searching for optimistic and optimal solutions. We argue that future studies could shift their focus to better account for societal and economic targets. Participatory approaches can help to ensure the feasibility of future solutions to reduce water pollution from food production.

Sustainable use and management of nutrients is an important issue for food, energy and water systems. The close connections between the three systems, reflected by the “nexus” concept, warrant an integrated approach to nutrients management across the nexus. In this paper, dynamic modelling of nutrient flows in a local food-energy-water system is presented and applied to a simplified case study. The model was used to simulate several scenarios affecting nitrogen flows and stocks to assess the impact of a) the level of local wheat production, b) the selection of energy generation technology, and c) the management of available nutrient resources (digestate and straws). The simulation results showed that varying the proportion of locally produced wheat significantly affects the surface runoff and the nitrogen content in a local water body, with the latter increasing by nearly 70% in 50 years if about half of the wheat consumed is produced locally as opposed to being 100% imported. The introduction of anaerobic digestion as an energy generation option helps to supply more electricity, reduce the imported fertiliser, and also significantly reduce the landfilled nitrogen nutrient by up to 60 times, due to the reuse of the anaerobic digestate. On the other hand, a balanced consideration should be given between using the straw as fertiliser and as feedstock for energy generation. This work offers a first analysis of the food-energy-water nexus with a focus on nutrient flows and stocks. The modelling approach has the potential to inform holistic decision making with respect to nutrient usage, efficiency and the related environmental impact in the design of a local system for meeting the demand for food, energy and water.

In this study, Sea Water Bread (SWB), made with food grade sea water was compared with control bread made with Tap Water (TWB). Sea water’s influence on chemical-nutritional properties of bread was investigated. Contents of salt, macro/micro-elements, basic nutrients, polyphenols, antioxidant activity, olfactory characteristics, and volatile components were analyzed. Chlorides’ analysis showed SWB had a lower salt content than TWB and it was confirmed by ICP-OES investigation. An electronic nose confirmed differences between the groups of aromatic molecules of the bread typologies, as well as the profiles of the volatile molecules by GC-MS.