Final Report: High Flux Nanofiltration Membrane for Emerging Contaminant ControlEPA Contract Number: EPD14007
Title: High Flux Nanofiltration Membrane for Emerging Contaminant Control
Investigators: Fokema, Mark
Small Business: Aspen Products Group, Inc.
EPA Contact: Richards, April
Project Period: May 1, 2014 through April 30, 2015
Project Amount: $100,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2014) RFA Text | Recipients Lists
Research Category: SBIR - Drinking Water Treatment and Monitoring , Small Business Innovation Research (SBIR)
A variety of inorganic and organic 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. Although the concentrations of these emerging contaminants is very low (ng/L), the effects on human and aquatic health of persistent exposure to these compounds are not well understood and are 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 is able to reject emerging contaminants along with naturally occurring organic matter and inorganic salts at significantly reduced costs relative to existing membranes is under development in this program. The membrane technology can be used to improve the quality of surface, ground and even wastewater streams in both new and retrofit installations.
Membranes capable of selectively permeating large amounts of water over undesirable organic and salt species were prepared and characterized. Water permeabilities several time greater than conventional nanofiltration membranes enabled high water fluxes to be achieved at greatly reduced feed pressures.
The ability of the membrane to reject NaCl, Na2SO4, MgCl2, MgSO4, humic acid, natural organic matter, organic dyes, and selected emerging contaminants was quantified, and the membrane’s ability to resist fouling in the presence of humic acid and colloidal silica was studied over the course of several hundred hours. Stable organic and salt rejections were demonstrated throughout.
The impact of membrane use in a ~20 million gallon per day (MGD) nanofiltration water treatment plant was modelled. Reduced capital costs were realized through the use of higher flux membrane elements, while operating costs were reduced simultaneously through membrane element operation at a significantly reduced feed pressure. The company anticipates that the membrane will reduce the cost of producing water from the nanofiltration train by nearly 30 percent.
The membrane technology demonstrated under the Phase I project can be packaged into a high-flux, low-feed pressure membrane element product that can be readily adopted by the nanofiltration industry. In addition to significantly reducing the cost of water production, water quality also can be improved by reducing the concentration of emerging contaminants in the product water.
The market for membrane technologies for drinking water treatment recently has been experiencing double digit growth and is expected to encompass nearly $2 billion in the U.S. in 2015. Although the market for nanofiltration products is a relatively small portion of the overall membrane market, the nanofiltration market is expected to grow at a compound annual growth rate of 16 percent and reach $338 million in the U.S. by 2019. The market for nanofiltration products is dominated by drinking and wastewater treatment applications. Within the drinking water segment, the main demands are for nanofiltration water softening membranes and nanofiltration membranes that remove color and total organic carbon.