Comparison between Reverse Osmosis Desalination Cost Estimation Trends (original) (raw)

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].