Total water costs on a standard basis for three large, operating , S.W.R.O. plants

Abstract

There are now several large seawater reverse osmosis plants in operation with capacities in the range of 19,000 to 57,000 M3/D ( 5 to 15 MGD). Only limited cost data has been presented, primarily capital costs or bid prices. In a few cases the calculated total cost of water has been reported in the literature, but none of the reported costs follow the standard format (Ref 1 & 2) which was recognized at the 1988 Bahrain “Workshop on Production Cost of Water” sponsored by Water Sciences and Technology Association (Affiliate of I.D.A.) As result the reported costs are sometimes misleading and frequently misunderstood, leading to uncertainty about real costs. This is unfortunate since realistic total water cost information is vital if desalination technology is to begin to realize it's full potential. In this paper the author undertakes to analyze and correlate available operating and cost information for three large Seawater Reverse Osmosis (S.W.R.O.) plants, now in operation. From this data, total capital and total water costs are calculated (following the recognized format) and compared. For a second comparison, a new set of “normalized” calculations are presented, using equal fixed cost rates and electric power costs. The “normalized” total water costs for the three plants are relatively close, and this cluster of costs provides further credibility to the S.W.R.O. process for large plants. Further the costs appear to be quite reasonable and this should provide support for those now considering seawater desalination. The paper was sent to representatives of each of the three plants for which cost analyses were made, inviting review and prepared discussion.