Water Resources Research Act Program

Details for Project ID 2008DE129B

Exploring Direct Contact Membrane Distillation (DCMD) as for Water Purification

Institute: Delaware
Year Established: 2008 Start Date: 2008-03-01 End Date: 2009-02-28
Total Federal Funds: $1,750 Total Non-Federal Funds: $3,500

Principal Investigators: Caitlin Wilson, Steven Dentel

Project Summary: Fresh water sources are limited in Delaware as well as many other places, nationally and internationally. In fact, 97% of the worlds water contains salt and is unsuitable for potable use. Therefore, desalination is a critical process sometimes employed in order to convert sea water and brackish water into fresh water. The most common methods of desalination include flash distillation, reverse osmosis, and electrodialysis. However, a newer and promising desalination method known as membrane distillation uses waste heat to remove salt from water. In membrane distillation, feed and permeate compartments are separated by a hydrophobic membrane. A temperature difference between two compartments leads to differing water vapor pressures, causing water vapor transport across the membrane. Vapor transport from the warm compartment produces distilled water in the cooler compartment. Since it is possible to warm the compartment well below the boiling point of feed, the use of low-grade thermal energy is possible. In many situations, this energy is available at minimal cost, so membrane distillation will not be as costly as typical desalination processes, which are more energy intensive. The overall goal of this research is to arrive at a new approach to the removal of salt from water, which could have an enormous impact on the way we purify water, locally and globally.