Comparative Cost Evaluation of Desalted Water Supply versus Alternative Freshwater Supply from a Conventional Source

Abstract

A costing procedure was developed in the desalt studies made in Texas so that calculations of the cost of water supply produced by saline water conversion could be compared to the cost of providing an alternative freshwater supply from a conventional source. In studies made by the Texas Water Development Board, the cost of desalted water is generally higher than the cost of water from alternative sources. For desalting, the elements included in the costing procedure were: well fields for saline feedwater supply; intake system and pumping station; pipelines; pretreatment for saline water; the desalting plant ; and brine disposal. For a conventional water supply system the elements of cost included were raw water cost; well field or intake system; pipeline and required pumping stations; and a conventional water treatment plant. The final economic justification of a desalt project may include such factors as chemical quality comparisons, secondary benefits, and project life comparison to future availability of alternative supply. The Texas Water Development Board considers that desalting is a very practical solution to the interim water supply problems that exist in many areas of the state.