High Flux Nanofiltration Membrane for Emerging Contaminant Control

A variety of organic and inorganic contaminants originating from municipal, agricultural, and industrial wastewater sources are being found at increasing frequency in the Nation’s natural and drinking water supplies. These “emerging contaminants” include pharmaceuticals, antibiotics, steroids/hormones, flame retardants, perfluorinated compounds, personal care products, and herbicides/pesticides. While the concentrations of these emerging contaminants, is very low, the effects on human and aquatic health of persistent exposure to these compounds are not well understood and a source of concern. Existing technologies that remove these contaminants have high capital and operating costs, thereby limiting their use in drinking water production. A high-flux, fouling-resistant nanofiltration membrane that rejects these emerging contaminants while simultaneously addressing conventional drinking water treatment requirements is being developed in the proposed program. The membrane produces water at five to ten times the throughput of conventional nanofiltration membranes, facilitating operation at significantly reduced feed pressures with fewer membrane elements. The lower energy consumption and reduced capital costs enables low-emerging contaminant, nanofiltration-quality, drinking water to be produced at as little as 67% of the cost of current membrane technologies. The Phase I program demonstrated the high water productivity and fouling resistance of the composite membrane structure in a subscale demonstration. The Phase II program will refine the membrane structure, scale-up membrane fabrication, produce intermediate-scale membrane elements, and demonstrate long-term membrane element operation on surface water sources. The market for nanofiltration systems is currently estimated to be $0.4 billion and growing at a compound annual growth rate of 16%, primarily due to a rising demand for potable water, reduced freshwater sources, environmental restrictions on industrial and municipal wastewater discharges, and increased demand for water reuse. Although water and waste water treatment accounts for three quarters of the current nanofiltration market, nanofiltration is also being used with greater frequency in food and beverage, chemical and petrochemical, pharmaceutical and biomedical, metalworking, agriculture, textiles, and solid waste management markets.