Seawater Desalination for Municipal Water Production (original) (raw)
Related papers
Desalination, 2012
This paper examines optimal input allocations in the context of a seawater desalination reverse osmosis (SWRO) system used to produce municipal water. The objective of this research is to better understand the effects on the total costs and the input portfolio of a SWRO system from changes in water quality, daily operations schedule, and input prices. A cost-minimization model is developed, a production function is estimated, and sensitivity analyses are conducted. The results indicate that lower total system costs are associated with warm-weather water quality parameters and lower input prices. Conditional findings indicate a range of system characteristics that yield, in optimality, moderate levels of both capital and hourly operations. This finding is due to the substitution between capital and daily-hours of operation. Additionally, an interruptible (or off-peak) electrical power supply regime is evaluated and determined to contribute to lower system costs under realistic conditions.
The Economics of Reverse Osmosis Desalination Projects
Journal of Membrane and Separation Technology, 2016
Desalination applications based on reverse osmosis (RO) technology today comprise over 50% of the capacity of all desalination systems worldwide and represent 75-85% of new desalination projects being implemented. The major reason for the shift in desalination projects to RO technology is the high energy efficiency of the RO process. There are three major application categories of large capacity, RO-based desalination projects: brackish RO; advanced municipal wastewater reclamation; and seawater RO. In the two first categories (brackish RO and wastewater reclamation), the systems' configuration and equipment components are well defined. Therefore, project costs and operating expenses are fairly predictable. In seawater RO desalination systems, the RO process configuration is also very similar; however, some variability exists regarding the configuration of seawater water delivery and feed water pretreatment. The rest of the system's components and system operation methods are very uniform. However, an evaluation of published cost data of medium-to large-scale water RO desalination projects illustrates significant variability in costs of desalination systems. This paper will analyze current economic conditions of seawater desalination, and highlight the limitations and possibilities of additional improvements of the economics of the SWRO desalination process.
Comparison between Reverse Osmosis Desalination Cost Estimation Trends
Fresh water scarcity in many countries limits sustainable development; in many cases sea water desalination represents an ideal solution. Reverse osmosis membrane technology has developed over the past 50 years and it has 80% share in the total number of desalination plants installed worldwide. In this study, the approaches adopted for the economic evaluation of SWRO desalination processes, cost estimation programs and published equations that evaluate the capital and the total cost of desalinated water have been reviewed, analyzed and evaluated for further implementation of desalination plants. Four methods have been selected to simulate different desalination capacities. All costs have been updated using ENR cost index for 2015. The results show that for large capacities, the capital and unit costs are in accordance with a percent deviation when comparing different cost estimation procedure. WTCOST and DEEP software show comparable unit cost 0.96/m3and0.96/m 3 and 0.96/m3and0.99/m 3 , respectively; while for capacities less than 1000 m 3 /d there is a significant percent deviation between methods. 1. Introduction Today, reverse osmosis membranes are the one of leading technologies for the desalination process, as they are applied to a diversity of salt water resources using membrane system design and tailored pretreatment. A wide variety of research and general information on RO desalination is available; however, a direct comparison of seawater and brackish water RO systems is necessary to highlight similarities and differences in process development [1]. One of the most critical features of any water treatment project is the cost. For membrane desalination, decreasing costs and producing higher water quality are among a number of important reasons why this technology continues. The cost of RO desalination plant is divided into direct capital cost, indirect capital cost and annual operating cost. Direct capital costs include the cost of land, major and auxiliary process equipment, and construction costs. Freight and insurance, construction overheads, and contingency costs are part of the indirect capital costs. While, annual operating costs are after plant commissioning and during plant operation and include chemicals, energy, wages, plant maintenance, expenditures etc. A wide distribution of these cost items are reported [2-3]. An exploratory study has been conducted to review the approaches adopted for the economic evaluation of SWRO desalination processes. Cost estimation programs that evaluate the capital and the total cost of desalinated water have been developed by several research and commercial entities. These water desalting cost programs enable estimation of desalting costs for sea water or brackish water using various technologies. Equations representing cost models have been developed by several authors. In addition, conceptual cost estimates for desalting process have been developed in graphical form [4].
Desalination, 2013
Desalination capacity has rapidly increased in the last decade because of the increase in water demand and a significant reduction in desalination cost as a result of significant technological advances, especially in the reverse osmosis process. The cost of desalinated seawater has fallen below US$0.50/m 3 for a large scale seawater reverse osmosis plant at a specific location and conditions while in other locations the cost is 50% higher (US$1.00/m 3) for a similar facility. In addition to capital and operating costs, other parameters such as local incentives or subsidies may also contribute to the large difference in desalted water cost between regions and facilities. Plant suppliers and consultants have their own cost calculation methodologies, but they are confidential and provide water costs with different accuracies. The few existing costing methodologies and software packages such as WTCost© and DEEP provide an estimated cost with different accuracies and their applications are limited to specific conditions. Most of the available cost estimation tools are of the black box type, which provide few details concerning the parameters and methodologies applied for local conditions. Many desalination plants built recently have greater desalinated water delivery costs caused by special circumstances, such as plant remediation or upgrades, local variation in energy costs, and site-specific issues in raw materials costs (e.g., tariffs and transportation). Therefore, the availability of a more transparent and unique methodology for estimating the cost will help in selecting an appropriate desalination technology suitable for specific locations with 2 consideration of all the parameters influencing the cost. A techno-economic evaluation and review of the costing aspects and the main parameters influencing the total water cost produced by different desalination technologies are herein presented in detail. Some recent developments, such as the increase of unit capacity, improvements in process design and materials, and the use of hybrid systems have contributed to cost reduction as well as reduction in energy consumption. The development of new and emerging low-energy desalination technologies, such as adsorption desalination, will have an impact on cost variation estimation in the future.
Modeling of environmental aspects related to reverse osmosis desalination supply chain
Environmental Health Engineering and Management, 2020
Background: This study aimed to model optimization of strategic environmental management decisions in the operation of reverse osmosis desalination, emphasizing the costs required for the environmental protection during the production of freshwater using reverse osmosis technology. Methods: This analytical research was conducted in five cities of Hormozgan province in Iran for 18 months from February 2018 to September 2019. The research includes eight phases of defining the research problem, data collection, preliminary data analysis and decision criteria, mathematical modeling, model validation, information preparation, analysis and finally discussion, conclusions and suggestions. The main environmental issues were the carbon dioxide (CO 2) release rate due to power demand and rejected brine water (RBW) were entered the mathematical model. Results: The desalination plants of Abu Musa, Bandar Abbas, Qeshm, Sirik, and Hormoz with water production flow rate of 2100, 89 000, 5300, 3300 and 1500 m 3 /d can generate 2360.82, 100053.80, 5958.260, 3709.86 and 1686.30 tons/year of CO 2 emissions respectively. This output requires 1.35, 57.47, 3.42, 2.13 and 0.97 million USD for controlling the process, respectively. For reduction of the negative effect of RBW 0.75, 22.79, 1.78, 1.15 and 0.55 million USD respectively, is needed. Conclusion: Recommendations for environmental impacts protection of RBW, for desalination capacity up to 50 000 m 3 /d, are; (a) for desalination capacity up to 50 000 m 3 /d; dilution the RBW using raw water before entering into the sea, (b) for capacity of 50 000-100 000 m 3 /d; dispersing RBW in sea using diffuser, and (c) for capacity more than 100 000 m 3 /d; hybrid water desalination plants and power plant. Application of power plant cooling water to dilute RBW may reduce cost.
The design of reverse osmosis (RO) networks is investigated here using a mixed-integer non-linear programming (MINLP) approach based on a superstructure. A flexible superstructure that contains all possible alternatives of a potential RO network was developed and was used in the synthesis of RO networks. The networks were designed by using DuPont's B10 Hollow Fiber module. For fixed freshwater demand and quality, the total annualized cost of the RO networks (capital and operating costs) is minimized in order to find the optimal operation and configuration of RO systems for three different feed concentrations and with seasonal variation of seawater temperature. It is found that seasonal variation in seawater temperature has a significant effect on the design and operation of RO systems. Also the results demonstrate that the variation in the number of modules required for the operation of RO process in high and low temperature seasons offers the possibility of flexible scheduling of cleaning and maintenance of membrane modules.
Overview of the cost of desalinated water and costing methodologies
Desalination, 2007
In the last decade desalination has been considered as a solution for potable water needs only for specific water scarcity countries having cheap fuel. Now, desalination is extensively used, even where it was unthinkable twenty years back, due to reduction in desalination cost. The cost reduction is due to new developments and improvements in desalination technologies, particularly in RO technology. The RO is a well accepted technology due to recent increase in energy prices and takes up a major share in worldwide market. But, it is not able to achieve its proper share in the Arabian Gulf market due to difficult seawater composition and extensive historical use of thermal desalination. But RO still has potential in hybrid systems in the Arabian Gulf to account for seasonal and night to day fluctuations in the demand for power and water. There is a need for an accurate methodology for evaluation of desalination costs to help in selection of appropriate technology suitable for a specific location, for process design and other requirements. However, existing methodologies and software packages do not account for all the parameters that contribute for desalting cost and their accuracy is limited to specific conditions. This paper presents an overview of the trends in desalination costs for major desalination technologies like Multi Stage Flash, Multi Effect Distillation and Reverse Osmosis and review of costing methodologies.
Journal of Water and Wastewater, 2023
Nowadays, decreasing access to sustainable water sources has pushed the water shortage to water stress and water crisis in some cases. This phenomenon has led to more and more researchers and craftsmans' efforts to achieve cost-effective commercial processes for a sustainable supply of water. Reverse osmosis process showed suitable potential for supplying the human's required drinking water among all the water treatment processes. However, this process needs economic studies in macro-industrial levels. Neka power plants' reverse osmosis desalination of seawater has been designed for production of 6,000 m 3 /day desalinated water. Feed water of this plant is supplied from the Caspian Sea with total dissolved solids of 15,000 mg/L and electrical conductivity of 20,000 \S/cm. Based on the results, required capital cost of this plant is 6millionandannualvariablecostof6 million and annual variable cost of 6millionandannualvariablecostof1.232 million is needed for desalination plant operation. Final fixed price of the desalinated water has been calculated 0.684percubicmeterofdesalinatedwaterwiththeconsiderationof20years′plantlifecycle.Break−evenpointofthedesalinationplanthasbeenobtainedlessthan6yearsandlessthan2yearswithsalespriceof10.684 per cubic meter of desalinated water with the consideration of 20 years' plant life cycle. Break-even point of the desalination plant has been obtained less than 6 years and less than 2 years with sales price of 1 0.684percubicmeterofdesalinatedwaterwiththeconsiderationof20years′plantlifecycle.Break−evenpointofthedesalinationplanthasbeenobtainedlessthan6yearsandlessthan2yearswithsalespriceof1/m 3 and 2 $/m 3 of desalinated water, respectively. Results show that reverse osmosis based desalination systems are a suitable replacement for conventional freshwater sources.
Investment and production costs of desalination plants by semi-empirical method
2008
Energy consumptions and costs of desalting systems are among the main parameters affecting the choice of certain desalting system and desalted water final cost. The paper describes a semi-empirical method for determining production and investment costs taking into account plant capacity, availability, energy price and consumption, plant capital cost, membrane service life and other process variables. This study concerns the different desalting processes of seawater, namely distillation multi-stage multi-flash, distillation multi-effect, vapour compression and the reverse osmosis. Results show that this method can give a good estimation of the investment and production costs for the concerned processes. Surely, this method can be useful especially in the maturation and the feasibility of any project in the field of desalination. So that most decisions of realization of any project can be taken in a relatively short time and therefore, costs of engineering can be reduced considerably.