Specialty chemicals company Lanxess expands its range of membrane elements for reverse osmosis (RO). The new Lewabrane RO ULP (ultra low pressure) line has three product grades available for water treatment. They reportedly display higher water permeability than the standard elements, while offering a high level of rejection of critical substances. The operating pressure required in the pressure vessel is 40% lower, according to the company. The new membranes are also a good option for removing trace elements from wastewater and drinking water.
“The new ULP products are recommended for applications in which a high flow rate, moderate salt rejection and low power consumption are the primary design parameters. Fields of application therefore are the cost-efficient filtration of drinking water and high-tech wastewater treatment,” says Alexander Scheffler, director membrane business in the Lanxess Liquid Purification Technologies business unit (LPT).
The advantage of the membranes is their ability to remove such organic compounds almost entirely even at low operating pressures. To reduce the formation of organic deposits – i.e. typical biofouling – in wastewater, the ULP membrane has the most hydrophilic surface of all the Lewabrane product grades. A thin, protective film of water forms on the membrane surface, which reduces the adsorption of organic substances.
The ASD feed spacers, which are inserted in the membrane elements to create space between their surfaces for flowing water also reduce fouling. They have an alternating strand design (ASD), comprising filaments of different thickness, which cause uniform overflow and thus counteract biofouling.
