S.A. Ghassemi; Sh. Danesh
Abstract
In this research a fuzzy decision making model was presented to assess and rank various water desalination methods and ultimately select the best alternative. The desalination alternatives which were investigated included Reverse Osmosis, Electrodialysis, Multi-Stage Flash Distillation, Multi-Effect ...
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In this research a fuzzy decision making model was presented to assess and rank various water desalination methods and ultimately select the best alternative. The desalination alternatives which were investigated included Reverse Osmosis, Electrodialysis, Multi-Stage Flash Distillation, Multi-Effect Distillation, Vapor Compression and Ion Exchange. The model was carried out in three steps: problem definition, fuzzy computations and ranking of alternatives. The hierarchy structure used for problem definition included 5 levels of: goal, main criteria, sub-criteria, factors, and desalination alternatives. The criteria, sub-criteria and factors and the relative importance of each were determined based on the experts' opinions and the literature results. In the next step, by using Chang's extent analysis, various desalination alternatives were evaluated on the basis of the selected criteria, sub-criteria and factors. For assessment of accuracy and its practical application, the model was used in a case study concerning quality management of the brackish water from a number of wells located in the City of Torbat-e-Heydaryieh. The results of the research indicated that the Electrodialysis process, with the final weight of 0.255, was the best method of desalination for the investigated wells. The sensitivity analysis also showed that the fuzzy model has a low degree of sensitivity in regard to the changes in criteria weights, meaning that the results are adequately reliable. The results furthermore pointed out that the fuzzy analytical hierarchy process can be used as an efficient tool for systematic decision making in the area of qualitative water resource management.
S.A. Ghassemi; Sh. Danesh; A. Alizadeh
Abstract
Abstract
One of the major aspects of water resources management in the arid and semi-arid regions is the use of unconventional water sources such as effluents from wastewater treatment plants. As a result, assessment of water supply potential as well as fertilizer values of these unconventional water ...
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Abstract
One of the major aspects of water resources management in the arid and semi-arid regions is the use of unconventional water sources such as effluents from wastewater treatment plants. As a result, assessment of water supply potential as well as fertilizer values of these unconventional water sources is an important issue in any comprehensive resource management program. In this study, the water supply potential and fertilizer values of the effluents from the City of Mashhad wastewater treatment plants (Olang, Parkand-Abad #1 & Parkand-Abad #2) was assessed based on: 1) the effluents' nitrogen and phosphorus contents, 2) common types of agricultural crops in the region (wheat, barley, tomato), and 3) the crops water and fertilizer requirements over their growing season. The results of this research indicated that the water supply potential of the effluents from above mentioned wastewater treatment plants for irrigation of wheat, barley and tomato are equivalent to 962, 870 and 729 hectares, respectively. Moreover, based on the results of the integrated model used in this research, the use of the effluents can provide 87.2, 74.4 and 133.6 kg.ha-1 available nitrogen and 36.7, 31.7 and 62.0 kg.ha-1 phosphorus for wheat, barley and tomato, respectively. In terms of economic assessments, the water value of the effluents corresponded to 89.6×106 Rials for wheat, 67.4×106 Rials for barley, and 125.0×106 Rials for tomato. In terms of fertilizer value, the corresponding economic assessment represented values of 1.97×109, 1.44×109, and 4.68×106 Rials. In general, the net results of the economic analysis performed indicated that the use of the effluents from the City of Mashhad wastewater treatment plants in agriculture can reduce the cost of production by 33, 31 and 28 percent for wheat, barley and tomato, respectively.
Keywords: Wastewater, Agriculture, Water Resource, Nitrogen, Phosphorus, Economic Analysis
