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Abstract: The refurbished SWRO plant of Eni Gela in Sicily has been working for 3 years at constant output and with low maintenance requirements. The plant consists of 4 trains, each with 74 pressure vessels and 6 elements per vessel, producing 4 × 4,200 m3/d permeate. The plant has required cleaning only twice within the last 34 months and is still producing permeate at lower pressure and substantially better quality than originally projected. The original plant fitted with HFF permeators had a history of problems due to fouling and was retrofitted with spiral wound elements in 2003. The retrofit element, FILMTEC™ SW30HR-320, was selected as it had the widest feed spacer commercially available in the market and was therefore specifically suited to water with known heavy fouling potential. In this paper the past and recent performance of the plant is discussed. Normalized data show the evolution of the performance on a weekly basis. It can be shown that both the normalized feed pressure and the salt concentration in the permeate are still lower than the projected design values after 3 years, respectively. The paper also discusses the factors which have contributed to this excellent performance, such as design and operation of the pretreatment, the RO section, and specific properties of the spiral-wound membrane element. [Copyright &y& Elsevier]

Abstract: Until the end of the 90''s the RO desalination technology for medium and large capacities was based mainly upon two configurations of membrane modules: spiral-wound elements and hollow fiber bundles (HF). The retirement of Permasep® HF (DuPont) leaving HOLLOSEP® (Toyobo) as being the only alternative for the direct replacement of Permasep, brought a challenge to the makers of spiral elements in the sense of system retrofit to convert existing HF membrane plants into some of the most advanced spiral-wound membrane plants. The major criteria for success was to achieve substantial improvements in the economy and quality of the permeate produced at limited capital expenditure. Such improvements have become feasible with the considerable development of spiral-wound membranes in the recent years. In this paper the technical changes needed for the retrofitting have been systematically studied. After a short historical review, the paper discusses basic options for the retrofitting have been systematically studied. After a short historical review, the paper discusses basic options for two existing Permasep installations on the Canary Islands and in the Middle East, respectively. Specific characteristics, advantages and costs of various possible solutions are presented. Two case studies are discussed for the 3×4,700 m3/d seawater RO plant in Agragua on the Canary Islands and for the 4×4,200 m3/d seawater RO plant in Gela in Sicily. Plant performance data for 8 months and 19 months respectively is presented. [Copyright &y& Elsevier]