Water. desalination + reuse

May/June 2013

Water. Desalination + reuse

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SHOWCASE GE launchEs mEmbranE for touGh-to-trEat watErs A new low-fouling reverse-osmosis (RO) desalination membrane for brackish water from industrial processes that is difficult to treat has been introduced by GE. The AG LF series resists degradation from water containing bacteria, colloids and other materials that foul and shorten membrane element life. GE successfully pilot-tested the new membranes in Asia, where customer experience showed that they required fewer cleaning cycles compared with conventional brackish membranes in tough applications, such as steel production, power plants and plating processes. GE says the membrane can reduce the time between cleanings by up to 50%, although actual results will vary with specific application conditions. It features a unique coating technology that improves cleaning cycles, reduces pressure and reduces friction on the surface of the membrane, making it resistant to organic fouling. "Our new low-fouling RO membrane offers higher efficiency with less frequent cleaning cycles, leading to extended life, lower operating pressure and reduced environmental impact. Now offered to our industrial and municipal customers around the world, this new membrane technology specifically addresses tough-to-treat water," said Yuvbir Singh, general manager, engineered systems — water and process technologies for GE Power & Water. lanXEss launchEs smallEr-bEad mds IX rEsIns Lanxess has expanded its Lewatit line of ion-exchange resins to include a new generation of finely dispersed grades. Monodisperse, macroporous chelating resins of this kind significantly enhance the efficiency of brine treatment for chloralkali electrolysis based on membrane technology. Furthermore, they effectively help to prevent damage to the increasingly sensitive, latest-generation membranes. The critical difference between the new resin grades and those sold previously is the bead diameter. In the monodisperse small (MDS) grades, such as Lewatit MDS TP 208, the diameter is only 390 μm, or 40% smaller than that of the monodisperse grade Lewatit MonoPlus TP 208. This size difference translates into roughly twice the bead surface per unit of volume. As a result of this difference, says Lanxess, the MDS grades display improved kinetics, a higher degree of regeneration and a significantly increased total and operating capacity specifically for alkaline earth cations. At the same time, they have optimal mechanical and osmotic stability. Barium and strontium ions are removed from the brine with particular efficiency. This is a remarkable characteristic in view of the low selectivity of many other resins and their slow exchange kinetics. The chelating resins also bind the lighter elements in the alkaline earth group, such as calcium and magnesium. Their improved leakage is an important advantage, because the reduced leakage helps to increase the service life of the electrolysis membranes. In this respect, says Lanxess, the MDS resins have anticipated the continuous advancements in membrane development, because the concentration tolerances for alkaline earth ions will likely decrease further in the future. Resins in the MDS line give electrolysis operators a number of economic advantages, most of which are based on the following effects: • Longer life for the membranes and the resin • Lower operating costs as a result of lower regenerating agent requirements and less wastewater • Longer cycle times for the resin • Higher throughput in brine production. The new resin grades have already been used successfully on an industrial scale in Germany. PatEnt award for lockhEEd martIn GraPhEnE mEmbranE A graphene desalination membrane material name PerforeneTM has been awarded a patent for its designer Lockheed Martin, the arms manufacturer. The Perforene membrane was developed by placing holes that are ≤1 nm in a graphene membrane. These holes are small enough to trap the ions while dramatically improving the flow-through of water molecules, reducing clogging and pressure on the membrane. At only one atom thick, graphene is both strong and durable, making it more effective for seawater desalination at a fraction of the cost of reverse-osmosis systems. In addition to desalination, the Perforene membrane can be tailored to other applications, including capturing minerals, through the selection of the size of hole placed in the material to filter or capture a specific-sized particle of interest. Lockheed Martin has also been developing processes that will allow the material to be produced at scale. The company is currently seeking commercialization partners. advancEd turbIdIty mEtEr launchEd by PalIntEst A new Compact Turbimeter featuring QuadoptiX™ advanced testing technology has been launched by Palintest Ltd of the UK. Designed for the field professional to test turbidity in drinking water, wastewater and surface water, the Compact Turbimeter is built around the new The Compact Turbimeter. QuadoptiX optical bench. This new technology effectively uses two independent turbidity measurement systems for dual validation, resulting in improved reliability and accuracy - especially for samples with mobile or settling matter. The device features several operating modes, including continuous measurement, averaging and suspended solids. It can also test for a range of 0 - 1,050 NTU, with results also available in other units. Results are logged and tagged with operator and site identity information, along with calibration data for good laboratory practice compliance. The meter is waterproof to IP67, conforms to the ISO 7027 standard, and comes supplied in a hard case including stable calibration standards, test tubes, silicone oil and other accessories to provide the user with a comprehensive field kit for turbidity measurement. May-June 2013 | Desalination & Water Reuse | 37 |

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