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Designing integrated local production systems: A study on the food-energy-water nexus Texto completo
2016
Leung Pah Hang, Melissa Yuling | Martinez-Hernandez, Elias | Leach, Matthew | Yang, Aidong
Centralised production of essential products and services based on fossil fuels and large scale distribution infrastructures has contributed to a plethora of issues such as deterioration of ecosystems, social-economic injustice and depletion of resources. The establishment of local production systems that deliver various products for local consumption (e.g. food, energy and water) by making the best use of locally available renewable resources can potentially alleviate unsustainable resource consumption. The main objective of this work is to develop process systems engineering tools combined with the concept of resource accounting using exergy for the design of such local production systems. A general design framework comprising an optional preliminary design stage followed by a simultaneous design stage based on mathematical optimisation is proposed. The preliminary design stage considers each supply subsystem individually and allows insights into the potential interactions between them. The simultaneous design stage yields an optimal design of the local production system and has the capacity to include all design integration possibilities between the subsystems and generate a truly integrated design solution. The proposed methodology, which reflects generalised principles for designing local production systems, has been illustrated through a case study on the integrated design of the food-energy-water nexus for a designated eco-town in UK. It demonstrates the advantages of an integrated design of a system making use of local resources to meet its demands over a system relying on centralised supplies and a design without considering integration opportunities between subsystems.
Mostrar más [+] Menos [-]Water, Food Security and Agricultural Policy in the Middle East and North Africa Region Texto completo
2006
Shetty, Shobha
The Middle East and North Africa (MNA) region is one of the most water scarce regions in the world, with a regional annual average of 1,200 cubic meters per person (world average is close to 7,000). Water, not land, is now the limiting factor for improving agricultural production in the MNA region. Maximizing water productivity, not yield per unit of land, is, therefore, a better strategy for on-farm water management under such conditions. Raising water productivity requires integrated attention to improving technical, agronomic and management measures. Water User Associations greatly facilitate the implementation of integrated measures. Using satellite remote sensing technologies, planners and policy makers can make more effective decisions to ensure a stable supply of water for food and the environment. All MNA countries with the exception of Morocco are net importers of agricultural products. The greatest benefits for MNA will be generated by comprehensive domestic agricultural reforms, in tandem with higher market access in European and world markets. MNA governments will face issues relating to timing and sequencing of reforms. Given its current resources endowments and growth prospects, it is in the best interest for MNA countries to push towards proceeding with the liberalization of markets in developed countries. At the same time, they could ask for some sort of compensation for higher prices and lost preferences in the form of non-trade distorting financial schemes or even cash grants for those countries facing significant losses as a result. Countries will have to pay a particular attention to the implications of this gradual approach for government revenues, adjustment costs and credibility of reforms.
Mostrar más [+] Menos [-]Optimizing extraction and analysis of pharmaceuticals in human urine, struvite, food crops, soil, and lysimeter water by liquid chromatography-tandem mass spectrometry Texto completo
2017
Mullen, Rachel A. | Wigginton, Krista R. | Noe-Hays, Abraham | Nace, Kim | Love, Nancy G. | Bott, Charles B. | Aga, Diana S.
Human urine is an abundant, renewable resource that can be used as a valuable source of fertilizer because it is rich in nitrogen, phosphorus and potassium. As fertilizers derived from urine become more widely used, it is important to understand how excreted pharmaceuticals are transported from urine to the environment. Many pharmaceuticals are excreted from the human body in their native form; therefore, when urine is used as a fertilizer, biologically active pharmaceuticals can be released into the environment. The goal of this study was to develop sensitive methods for the analysis of pharmaceuticals in urine, struvite, lysimeter water, soil, and food crops using liquid chromatography with tandem mass spectrometry (LC-MS/MS). The ability to detect low levels of pharmaceutical residues in various environmental matrices will aid in assessing the potential risks associated with the field application of urine that is used to fertilize croplands. The optimized method reported in this paper, which utilizes solid phase extraction for sample clean-up and pre-concentration, offers analyte recoveries ranging from 29 to 112 percent, and detection limits ranging from 0.89 ng L⁻¹ to 0.0047 μg g⁻¹. The optimized extraction method provides intra-day and inter-day reproducibility of less than 10% for all analytes in all matrices investigated, with the exception for ciprofloxacin in urine. The use of isotope dilution for quantification proved necessary to compensate for matrix effects, especially in urine where matrix effects can range from about 21% to 79%. Overall, the method described here is robust and widely applicable to various types of environmental samples.
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