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Water scarcity is one key challenge mankind is facing. Seawater reverse osmosis desalination is a promising technology to solve it. However, further innovation which needs to go beyond product specifications is needed to decrease the total cost of water while at the same time, improving sustainability footprint. This paper describes a breakthrough step-change in innovation within the desalination industry: transitioning from wet-tested seawater reverse osmosis (SWRO) elements to dry-tested SWRO elements. This new concept has been achieved by DuPont thanks to a cumulation of significant breakthrough in reverse osmosis technology: continuous advancements in membrane chemistry, automated precision manufacturing, single source manufacturing, a robust quality control, and enhancements in testing methods. Dry SWRO elements offer significant advantages over wet elements, given the requirement to monitor and eventually replace preservation solutions for wet membranes. Dry membranes enable longer storage times, lower labor costs and easier longterm warehouse planning. Dry membranes are safer to install due to a 4 kg weight reduction and are easier to handle. From the sustainability point of view, the dry-test SW concept also brings plenty of benefits: (1) Reduces fresh-water consumption as no wet testing is required; (2) Eliminates wastewater generated during wet testing; (3) Significantly reduces energy consumption by skipping wet testing; and (4) the lower membrane weight will significantly decrease the environmental footprint of dry elements, reducing by up to 20% the CO2 generation during transportation. In a large desalination installation supplied with dry SWRO elements, the greenhouse gas emissions reduction equals those generated by a passenger vehicle driving more than 500,000 km. Additionally, dry SWRO elements offer the same water productivity and permeate quality as wet elements. [ABSTRACT FROM AUTHOR]

Water scarcity is being recognized as one of the main threats that mankind is facing globally. Reverse osmosis membrane technology has developed as a promising technology to address this problem. This increase has been driven as materials are improved and costs dropped. This is especially relevant for Middle East countries (ME), where population is located in arid and semi-arid regions with limited rainfalls and a high degree of evaporation due to the high temperatures the region is exposed to. Therefore, getting a robust element that is able to offer a stable salt rejection even after multiple cleanings is of utmost importance to sustain the population and economic growth of the region. This paper aims at demonstrating the superior durability of FilmTec™ membranes compared to other manufacturers. This superior durability has been reported in a number of desalination plants where FilmTec™ membranes lifetime has exceeded more than 10 years, but a quantification and a reliable comparison of such superior durability compared to other manufacturers in a controlled environment has not been completed to date. In this paper, FilmTec™ SW30XLE elements are exposed together with equivalent commercially available membranes from other suppliers to a durability study to simulate long term operation and to determine the evolution of the membrane specifications over time. Particular focus is paid to the changes in salt rejection. Membrane durability plays a determining role in membrane replacement, which ultimately has a critical impact on the economics of any desalination plant. In this study, it was determined that after a number of cleanings, the salt passage increase over time of the membranes from other suppliers was close to 3.5 times larger than the value experienced by FilmTec™ membranes. More specifically, the salt passage increase experienced by FilmTec™ in the first study was 22%, while the membrane from another supplier showed a 73% increase; and in the second study, FilmTec™ had a salt passage increase of 43% while the membrane from the other manufacturer had a 140% salt passage increase. In a 100,000 m3/d desalination plant, this enhanced durability showed by FilmTec™ elements might represent a 5.5% cost of water decrease in the reverse osmosis stage, and total savings of 1.34 US ¢/m3 in the whole plant, which can be translated into savings of 488,000 USD/y. [ABSTRACT FROM AUTHOR]

Abstract: To study the effect of water quality and operating parameters on membrane fouling, a comparative analysis of wastewater (WW) and seawater (SW) fouled reverse osmosis (RO) membranes was conducted. Membranes were harvested from SWRO and WWRO pilot plants located in Vilaseca (East Spain), both using ultrafiltration as pretreatment. The SWRO unit was fed with Mediterranean seawater and the WWRO unit was operated using secondary effluent collected from the municipal wastewater treatment plant. Lead and terminal SWRO and WWRO modules were autopsied after five months and three months of operation, respectively. Ultrastructural, chemical, and microbiological analyses of the fouling layers were performed. Results showed that the WWRO train had mainly bio/organic fouling at the lead position element and inorganic fouling at terminal position element, whereas SWRO train had bio/organic fouling at both end position elements. In the case of WWRO membranes, Betaproteobacteria was the major colonizing species; while Ca, S, and P were the major present inorganic elements. The microbial population of SWRO membranes was mainly represented by Alpha and Gammaproteobacteria. Ca, Fe, and S were the main identified inorganic elements of the fouling layer of SWRO membranes. These results confirmed that the RO fouling layer composition is strongly impacted by the source water quality. [Copyright &y& Elsevier]

Reducing membrane fouling caused by seawater algal bloom is a challenge for regions of the world where most of their freshwater is produced by seawater desalination. This study aims to compare ultrafiltration (UF) fouling potential of three ubiquitous marine algal species cultures (i.e., Skeletonema costatum- SKC, Tetraselmis sp.-TET, and Hymenomonas sp.-HYM) sampled at different phases of growth. Results showed that flux reduction and irreversible fouling were more severe during the decline phase as compared to the exponential phase, for all species. SKC and TET were responsible for substantial irreversible fouling but their impact was significantly lower than HYM. The development of a transparent gel layer surrounding the cell during the HYM growth and accumulating in water is certainly responsible for the more severe observed fouling. Chemical backwash with a standard chlorine solution did not recover any membrane permeability. For TET and HYM, the Hydraulically Irreversible Fouling Index (HIFI) was correlated to their biopolymer content but this correlation is specific for each species. Solution pre-filtration through a 1.2 μm membrane proved that cells and particulate algal organic matter (p-AOM) considerably contribute to fouling, especially for HYM for which the HIFI was reduced by a factor of 82.3. [ABSTRACT FROM AUTHOR]