With immediate effect HR (high rejection) types with membrane surface areas of 370 and 440 square feet and HF (high flow) types with membrane surface areas of 370, 400 and 440 square feet are available. Alan Sharpe, head of the RO Membrane Strategic Project in LANXESS's Ion Exchange Resins business unit says: “Our HR type elements are designed to provide extremely low salt passage in normal operation, with more than 99.7% salt rejection measured under standard conditions. The high rejection for critical ions like silica is also remarkable.” According to Sharpe, the HF types score well in terms of the high water productivity. The Lewabrane RO product types consist of spiral-wound polyamide composite membranes and are specially designed for treating water in industrial applications. Fields of application include the desalination of brackish and low-salinity waters, groundwater remediation and the production of boiler feed water required in power stations. The RO technology also facilitates demineralisation by particle removal in microchip manufacture.The elements in the Lewabrane RO product family have a standard length of 40 inches (1,016 mm) and a diameter of either eight inches (201 mm) or four inches (101 mm).Lewabrane B090 HF 4040, the membrane element with a diameter of four inches, has an ATD design. Due to a structure with anti-telescopic devices at the ends of the elements, the surface area of the membranes exceeds that of other commercially available elements by almost 6%. The bigger surface area results in higher water productivity. The superior permeate flow rate is 9.4 cubic metres per day on average under standard conditions, with a salt rejection of 99.5%.“The combination of membrane filtration and ion exchange ensures that efficiency and economy can go hand in hand in industrial applications,” says Sharpe. Since the group offers both technologies, such process combinations are particularly attractive. “Our tried and tested Lewatit ion exchange resins and the new Lewabrane membrane elements can provide good cost performance, for example in the preparation of feed water for downstream EDI applications,” adds Sharpe. The membrane elements provide a stable lower-salinity permeate to minimize the load in downstream ion exchange and electrodeionisation (EDI) operations, thus improving the cost-performance ratio.
