Enabling Potable Reuse Of Wastewater Using Forward Osmosis: A Sustainable And Affordable Alternative To Reverse OsmosisEPA Grant Number: R834872
Title: Enabling Potable Reuse Of Wastewater Using Forward Osmosis: A Sustainable And Affordable Alternative To Reverse Osmosis
Investigators: McCutcheon, Jeffrey R
Institution: University of Connecticut
EPA Project Officer: Hiscock, Michael
Project Period: June 1, 2011 through May 31, 2016
Project Amount: $300,000
RFA: Advancing Public Health Protection through Water Infrastructure Sustainability (2009) RFA Text | Recipients Lists
Research Category: Drinking Water , Water
The potable reuse of wastewater is a promising concept that may lead to improved sustainability of municipal water production. Wastewater, however, contains a multitude of contaminants, such as those classified as “emerging contaminants”, that risk public health. Desalination technologies are capable of removing these harmful chemicals, but current technologies, like reverse osmosis (RO), are expensive due to large electricity requirements and fouling problems. Forward osmosis (FO) is an emerging membrane separations technology that is touted as an innovative, sustainable, and affordable alternative to RO. FO relies on an osmotically-driven water flux across a semi-permeable salt rejecting membrane. In one of the most viable configurations developed in part by the principle investigator (PI), osmotic driving force is generated by a thermolytic salt, which can be regenerated using only low-grade thermal energy. Desalination quality separation is thus enabled without the use of expensive electrical energy. FO has shown promise as an RO alternative in early studies by the PI and others, but the lack of an appropriate membrane has hindered its further development.
The goal of this proposed work is to systematically design and construct a novel thin film composite (TFC) membrane specifically tailored for wastewater treatment using forward osmosis. This membrane will then be evaluated for performance in wastewater reuse applications. This work will prove the viability of FO as an affordable, sustainable and effective wastewater treatment alternative that will enable potable reuse of wastewater.
The PI and his team will develop the first ever TFC membrane tailored for FO application to wastewater reuse. This membrane will employ a novel two tiered composite structure including a highly porous yet thin electrospun nanofiber nonwoven layer, which will support a traditional RO-type crosslinked polyamide selective layer. This membrane will be evaluated for productivity (water flux), selectivity (removal of emerging contaminants), and fouling propensity. Based on this performance data, the process will be modeled in Aspen to determine the energy requirements relative to RO.
Wastewater reuse using FO will greatly benefit the overall sustainability of the water delivery and treatment infrastructure by: 1) reducing the need for expensive, risky and energy intensive long distance conveyance; 2) eliminating the release of ecologically harmful emerging contaminants through secondary and tertiary treated wastewater effluent; 3) reducing the need for unsustainable withdrawals from fresh ground and surface water sources; 4) reducing the carbon footprint for water production, conveyance and wastewater treatment; and 5) providing drinking quality water for direct or indirect potable reuse using abundantly available low quality thermal energy for a low total water cost.