As for oily water treatment in food industries, the membrane technology has a large potential to reduce the operation time, equipment space and total costs. Using crude lecithin/water emulsion as a model of oily waste water, filtration characteristics on the flux and total organic carbon (TOC) rejection were investigated with a wide range of membranes in reverse osmosis, nanofiltration, ultrafiltration, and microfiltration. Constant flux and TOC rejection were obtained in crossflow filtration with hydrophilic membranes having smaller pores than the emulsion droplets (1-2 mum). Free phospholipids were removed with reverse osmosis membranes or nanofiltration membranes having high NaCl rejection abilities. When microfiltration membranes having larger pores than the emulsion droplets were used, the membrane characteristics such as the pore structure and hydrophobicity largely affected the filtration characteristics: asymmetric membranes gave relatively high fluxes when its loose side was used against the feed emulsion as a depth filter, symmetric membranes having a spongoid pore structure and a pore size similar to the emulsion droplets brought about almost 0 flux owing to an extreme progress of pore blocking, hydrophobic membranes of adequate pore sizes showed a possibility to result in the negative TOC rejection

Oil and gas extraction in the western United States generates significant volumes of produced water (PW) that is typically injected into deep disposal wells. Recently, crop irrigation has emerged as an attractive PW reuse option, but the impact on plant immune response is not known. In this study, we conducted a 3-month greenhouse pot study. Spring wheat (Triticum aestivum) was irrigated 3 times a week with 150 mL (∼80–100% of soil water holding capacity) with one of four irrigation treatments: tap water control, 10% PW dilution, 50% PW dilution, and salt water (NaCl50) control containing the same amount of total dissolved solids as PW50 to determine the effect on disease resistance. The wheat leaves were inoculated with either bacterial or fungal pathogens and changes in pathogenesis-related PR-1 and PR-5 gene expression were measured from the leaf tissue. PW50 experienced the largest relative suppression of PR-1 and PR-5 gene expression compared to noninfected wheat, followed by PW10, NaCl50, and the tap water control. A combination of PW contaminants (boron, total petroleum hydrocarbons, and NaCl) are likely reducing PR-gene expression by reallocating metabolic resources to fight abiotic stresses, which then makes it more challenging for the plants to produce PR genes to fight pathogens. This study provides the first evidence that plant disease resistance is reduced due to irrigation with reused PW, which could have negative implications for food security.

Recent years have shown increased awareness that the use of the basic resources water, food, and energy are highly interconnected (referred to as a ‘nexus’). Spatial scales are an important but complicating factor in nexus analyses, and should receive more attention – especially in the policy-oriented literature. In this paper, we ‘unpack' the nexus concept, aiming to understand the differences between water, food and energy resources, especially in terms of spatial scales. We use physical indicators to show the differences in terms of absolute magnitude of production and the distance and volume of physical trade, for seven resource categories: water withdrawal, crops, animal products, bio-energy, coal, oil, and natural gas. We hypothesize that the differences in trade extent are related to physical characteristics of these resources: we expect high priced, high density, geographically concentrated resources to be traded more and over longer distances. We found that these factors, taken together, can explain some of the differences in trade extent (and thus spatial scale involved), although for each individual factor there are exceptions. We further explore the spatial scales by showing the bidirectional physical trade flows at the continental scale for crops, animal products, bio-energy and fossil fuels. We also visualize how nexus resources are directly dependent on each other, using a Sankey diagram. Since both direct dependencies and physical trade are present, we investigate the role of resource-saving imports, which is a form of virtual trade. The resource-saving imports highlight the importance of continental and global scales for nexus analyses.

Water in oil emulsions would be prepared by silicones (SO), modified silicones (DC8500) and a food-grade stabilizer (starch 1). With increasing water contents, the emulsions turned from a liquid-like to gel-like behaviors with enhancing storage and loss modulus. When DC8500/SO was 1/17 with 10 wt% starch 1, a high internal phase emulsion can be obtained with 95 wt% water content. DC8500 and SO worked as efficient emulsifiers and possessed amphiphilic property to form emulsions with water in different ratios. A food-grade starch 1 was supplied as a stabilizer which can enhance both water content and strength of emulsion when added in a low concentration. Besides, it is indicated that the food-grade starches provided potential benefit on stabilizing emulsions in very low concentration.

Water, Energy and Food (WEF) are key elements of economic and social sustainable development, and present a complex nexus. Existed WEF nexus research is mainly confined to qualitative analyses, and it needs constant improvement and increases quantitative analyses. In China, water security is the most prominent problem in the WEF-nexus, which is manifested in the competitive relationship between food and energy production for water. Therefore, the matter of alleviating water resources stress has become a difficult and hot issue. After improving the existed water footprint accounting method for food and energy production, this study calculated the food water footprints (blue water footprint and green water footprint) in the 31 provinces of mainland China in 2015, as well as the blue water footprints of major energy systems (coal, oil, natural gas and thermal power generation). This study proposed water resources pressure index (IWS), water resources pressure contribution rate of food and energy (WCR), water consumption rate of food and energy (n) and competition composite index (CCI) of WEF, which were used to evaluate the consumption of water resources in food and energy production in different regions, and assess the intensity of competition for water resources in food and energy production. The results showed that the national food water footprint in 2015 was 690.8 Gm³, and the blue food water footprint was 287.8 Gm³. The main water-consuming blue energy water footprint was 18.5 Gm³, and coal production accounted for 9.9% and thermal power generation accounted for 87.6%. According to the competition indicators, the competition relationship among the administrative regions of the 31 provinces in mainland China was obtained. For example, 5 provinces had serious competition and 19 provinces had weak competition. The water consumption of the energy industry continues to grow rapidly by economic development. Corresponding measures should be taken according to the different competition levels for water resources.

Full self-sufficiency in cities is a major concern. Cities import resources for food, water and energy security. They are however key to global sustainability, as they concentrate a rapidly increasing and urbanising population (or number of consumers). In this paper, we analysed the dependency of urban inhabitants on the resource water for food consumption, by means of Dutch cities. We found that in extremely urbanised municipalities like Amsterdam and Rotterdam, people eat more meat and cereals and less potatoes than in other Dutch municipalities. Their current water footprint (WF) related to food consumption is therefore higher (3245l/cap/day) than in strongly urbanised cities (3126l/cap/day). Dutch urban citizens who eat too many animal products, crop oils and sugar can reduce their WF (with 29 to 32%) by shifting to a healthier diet. Recommended less meat consumption has the largest impact on the total WF reduction. A shift to a pesco-vegetarian or vegetarian diet would require even less water resources, where the WF can be reduced by 36 to 39% and 40 to 42% respectively. Dutch cities such as Amsterdam have always scored very high in international sustainability rankings for cities, partly due to a long history in integrated (urban) water management in the Netherlands. We argue that such existing rankings only show a certain – undoubtedly very important – part of urban environmental sustainability. To communicate the full picture to citizens, stakeholders and policy makers, indicators on external resource usage need to be employed. The fact that external resource dependency can be altered through changing dietary behaviour should be communicated.

This paper reports viscosity measurements of oil/water (O/W) monodispersed emulsions of different droplet diameters obtained in a membrane emulsification system. Hydrophilic microporous glass membranes of different pore diameters were used to prepare O/W emulsions. The results showed that the droplet diameter of the emulsions varied with the average pore diameter of the membrane. The average droplet diameter was found to be about five times greater than the average membrane pore diameter. A correlation was found for the relationship between the average droplet diameter and the emulsion viscosity. As the dispersed droplet size became smaller, the total surface area of the droplets increased. Therefore, the emulsion viscosity and the relative viscosity increased. Few studies have reported the viscosity of O/W emulsions with droplet diameter of 5 micrometers or more and an oil phase concentration of 10 vol% or less. In the present study a correlation between the droplet diameter and the emulsion viscosity was statistically established.

Water scarcity severely affects drylands threatening their food security, whereas, the oil and gas industry produces significant and increasing volumes of produced water that could be partly reused for agricultural irrigation in these regions. In this review, we summarise recent research and provide a broad overview of the potential for oil and gas produced water to irrigate food crops in drylands. The quality of produced water is often a limiting factor for the reuse in irrigation as it can lead to soil salinisation and sodification. Although the inappropriate use of produced water in irrigation could be damaging for the soil, the agricultural sector in dry areas is often prone to challenges in soil salinity. There is a lack of knowledge about the main environmental and economic conditions that could encourage or limit the development of irrigation with oil and gas effluents at the scale of drylands in the world. Cheaper treatment technologies in combination with farm-based salinity management techniques could make the reuse of produced water relevant to irrigate high value-crops in hyper-arid areas. This review paper approaches an aspect of the energy-water-food nexus: the opportunities and challenges behind the reuse of abundant oil and gas effluents for irrigation in hydrocarbon-rich but water-scarce and food-unsecured drylands.

Unheated and heat-aggregated β-lactoglobulin (β-lg) solutions were used to stabilize clove oil-in-water emulsion and limonene-in-water emulsion prepared by microchannel (MC) emulsification. The size of the MC array plate was 15 × 15 mm2 consisting of 100 parallel MCs fabricated on each side of the plate. The channels were 4 μm depth, 71 μm length, and 8.2 μm width, with the terrace length of 29.1 μm. Unheated and heat-aggregated β-lg effectively stabilized clove oil-in-water and limonene-in-water emulsions during production using MC emulsification. The emulsion droplets were steadily produced by the channels. The average diameter of clove oil droplets was around 17 μm, with both unheated and heat-aggregated β-lg, regardless of the concentration of β-lg. The average diameter of the limonene droplets was 18–26 μm depending on the conditions (unheated or heat-aggregated) and the concentration of β-lg. The coefficient of variation for all average droplet diameters was ≤8%, which was an indication of monodisperse droplets. Clove oil-in-water emulsion droplets became polydisperse within 2 h observation, whilst limonene-in-water emulsion droplets remained monodisperse over time. The stability of the oil droplets over time related to the solubility of the oil phases rather than the effects of β-lg as the surfactant. In addition, the droplet sizes at different surfactant concentrations seemed to relate to the viscosity ratio between the dispersed phase and the continuous phase rather than the effects of the surfactant.