AWWA MTC64638

In the current study, direct contact membrane distillation (DCMD) and forward osmosis (FO) are being investigated asalternative processes to enhance water recovery from brackish water, or more specifically, frombrines generated during brackish water desalination. DCMD is a non-pressure-driven separationprocess involving the transport of mass and heat through a hydrophobic, microporous membrane. The driving force for mass transfer is the vapor pressure difference across the membrane. InVEDCMD, warmer feed water is in contact with the feed side of the membrane and a coolerwater stream, under vacuum, is in direct contact with the opposite side of the membrane. Thetemperature difference between the streams and the vacuum applied on the permeate side of themembrane induce the vapor pressure gradient for mass transfer. The vacuum configuration ofDCMD has been shown to increase flux by up to 85% over the traditional configuration. FOis a non-pressure-driven separation process involving the diffusion of water through asemipermeable membrane. Water diffuses from a stream of low solute concentration to a drawsolution (DS) stream of high osmotic pressure. The driving force for mass transport is thedifference in osmotic pressure between the DS and feed solution. FO is shown to effectivelyconcentrate a variety of feed streams, including municipal wastewater, landfill leachate, greywater, fruit juices, and beverages. Studies have shown that both DCMD and FO canefficiently treat and highly concentrate a wide range of feed solutions. Includes 11 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

03/01/2007

Number of Pages:

11