Energy crisis is a worldwide problem; Pakistan is facing severe shortage of this, especially in summer. To overcome these crises, huge amount of fossil fuels is being utilized which ultimately resulting in their exhaustion. In order to cope up the increasing energy requirements, alternative energy sources are required that should be cost-effective, environment friendly and technically feasible. In this scenario biodiesel production from algae has attracted scientist's attention worldwide. At present, the major constraint in biodiesel production from algae is nutritional cost for algal growth. Present research work was planned to minimize nutritional requirements of algae by using food industry waste water as a medium for algal growth towards economical biodiesel production. For this purpose four algal strains (A1, A2, A3 and A4) collected from different fresh water sources were evaluated for their potential use in biodiesel production. The waste water was pre-analyzed to determine the concentrations of different nutrients. All algal strains were grown in Bristol media and different dilutions (10, 20, 40, 80 and 100%) of food industry waste water. Growth data was recorded for one week. The results showed that algal biomass gradually decreased with increasing dilution of food industry waste water and was found higher in 100% waste water concentration than other dilutions. Cultivated algae were harvested for biodiesel production with n-Hexane as oil extractant and NaOH as a catalyst in different combinations through a chemical process ca\led transesterification. The FFA (free fatty acid) profile of algae 1 (A1) by using 75% hexane and 0.5% NaOH combination was found to be higher than other combinations. Higher concentration of NaOH (1%) resulted in soap formation. The aforesaid situations, plus owing to the best biomass production using 100% waste water concentration, deemed algae 1 (A1) as the best candidate among all four strains evaluated for biodiesel production.

This study evaluates the strategic importance of gray water, which is a component of virtual water, defined as “the water embedded in key water-intensive commodities such as wheat” or “the water required for the production of commodities.” Estimation of gray water plays a role in ensuring water and water-dependent food security for both importing and exporting countries. Methodologies towards reducing virtual water for strategic crops in the Tunisian semi-arid region include irrigation techniques and the control of runoff. Resources management practices that improve family income especially for women and children, all contribute to food security.

A new paradigm for sustainable, integrated, water resources management is emerging from international conferences around the world. Its most succinct description is ‘the water–food–energy nexus for a green economy’. The water, food and energy nexus aims at the most efficient, best practice principles applied throughout the full food supply chain. This includes consideration of reducing wastage of the food for various reasons in the supply chain. This paper describes the global opportunities for better efficiency and resources conservation in the water, food, and energy supply chains with examples from Australia. Food wastage equates on average to 243 l day⁻¹ of water per person in the food they throw away, which is 1.5 times the daily water use per person in the UK. The concepts of virtual water and water footprint can help in identifying opportunities to save water by targeting reduction of wastage of food that has the highest virtual water content. A green economy aims at achieving optimised supply chain objectives in a manner that espouses the sustainability principle, gives due attention to environmental concerns and helps with eradication of poverty and hunger.

Energy production and development have impacts on non-energy sector concerns including food security, water security, and sustainable land-use. Biofuel pathways differ in the tradeoffs they present within this “energy-water-food nexus” (EWFN). In this study, we focus on algal systems in the context of these interrelated challenges. We present areas of key consideration within the EWFN for large-scale algal system planning and commercialization, consider key resource inputs and outputs in the context of traditional biofuels compared with algal biofuels, provide examples of current global practices and EWFN impacts pertaining to liquid biofuels, and discuss potential opportunities and tradeoffs in applications of algal systems to EWFN challenges. The work described here could be used as a guide for future analysis that could quantitatively evaluate algal system feasibility in terms of economic viability, spatially and temporally explicit environmental impacts and production levels, and cross-sectorial impacts.

China’s water resources are under increasing pressure from socioeconomic development, diet shifts, and climate change. Agriculture still concentrates most of the national water withdrawal. Moreover, a spatial mismatch in water and arable land availability—with abundant agricultural land and little water resources in the north—increases water scarcity and results in virtual water transfers from drier to wetter regions through agricultural trade. We use a general equilibrium welfare model and linear programming optimization to model interprovincial food trade in China. We combine these trade flows with province-level estimates of commodities’ virtual water content to build China’s domestic and foreign virtual water trade network. We observe large variations in agricultural water-use efficiency among provinces. In addition, some provinces particularly rely on irrigation vs. rainwater. We analyze the virtual water flow patterns and the corresponding water savings. We find that this interprovincial network is highly connected and the flow distribution is relatively homogeneous. A significant share of water flows is from international imports (20%), which are dominated by soy (93%). We find that China’s domestic food trade is efficient in terms of rainwater but inefficient regarding irrigation, meaning that dry, irrigation-intensive provinces tend to export to wetter, less irrigation-intensive ones. Importantly, when incorporating foreign imports, China’s soy trade switches from an inefficient system to a particularly efficient one for saving water resources (20 km ³/y irrigation water savings, 41 km ³/y total). Finally, we identify specific provinces (e.g., Inner Mongolia) and products (e.g., corn) that show high potential for irrigation productivity improvements.

S. Marjanizadeh, Charlotte de Fraiture, W. Loiskandl, 'Food and water scenarios for the Karkheh River Basin, Iran', 2014 | Increasing population and income and a wheat self-sufficiency policy are already stressing Iran's strategic Karkeh River Basin. Examining three scenarios to the year 2025, the authors of this study find: (1) business as usual leads to an aggravation of groundwater overdraft and may jeopardize the ecosystem services provided by the Hawr Al Azim marsh area; (2) giving priority to environmental flow requirements and restoring groundwater tables leads to a shortfall in wheat production; but (3) reducing agricultural water demand could maintain a certain level of food production. Appropriate policy could minimize the tradeoffs between food self-sufficiency, sustainable water use and farmers' income

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