Final Report: High Flux Nanofiltration Membrane for Emerging Contaminant ControlEPA Contract Number: EPD16001
Title: High Flux Nanofiltration Membrane for Emerging Contaminant Control
Investigators: Fokema, Mark
Small Business: Aspen Products Group, Inc.
EPA Contact: Richards, April
Project Period: February 1, 2016 through January 31, 2018
Project Amount: $300,000
RFA: Small Business Innovation Research (SBIR) - Phase II (2015) Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Drinking Water Treatment and Monitoring
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. While 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 a source of concern. Existing technologies that remove these contaminants have high capital and operating costs, thereby limiting their use in drinking water production.
Higher performing nanofiltration membranes that reject emerging contaminants, organics, and hardness ions, while allowing passage of monovalent salts were developed in this program. The membrane technologies can be used to improve the quality of surface, ground and even waste water streams in both new and retrofit installations.
A series of nanofiltration membranes capable of selectively permeating water over undesirable organic and salt species were prepared and characterized. Color removal membranes with water permeabilities several times greater than conventional nanofiltration membranes were developed along with water softening membranes capable of rejecting Mg2+ and Ca2+ salts while permitting high passage of monovalent salts, such as NaCl.
The ability of the membranes to reject NaCl, Na2SO4, MgCl2, MgSO4, humic acid, natural organic matter, and selected emerging contaminants was quantified, and the membranes’ abilities to resist fouling were examined. Residential-scale water softening spiral wound membrane elements were assembled stable element performance was demonstrated for over 460 hours.
The impact of water softening membrane use in a ~20 MGD nanofiltration water treatment plant was modeled. Reduced capital costs were predicted through the use of higher flux membrane elements, while operating costs were simultaneously reduced through membrane element operation at a significantly reduced feed pressure. Nanofiltration cost reductions of up to 23% may be realized through the use of the water softening membrane.
The membrane technologies developed in this program can be packaged into higher flux, lower feed pressure membrane element products that can be readily adopted by the nanofiltration industry. In addition to significantly reducing the cost of water production, water quality can also be improved by reducing the concentration of emerging contaminants in the product water.