Drexel University is conducting research with the overall objective of developing technologies to reduce freshwater consumption at coal-fired power plants. The goal of this research is to develop a scale prevention technology based on a novel filtration method and an integrated system of physical water treatment in an effort to reduce the amount of water needed for cooling tower blowdown. The filter is a self-cleaning metal membrane, using pulsed electric fields to dislodge particles on the filter.

The researchers are developing a filtration system and an integrated physical water treatment method. The filtration method utilizes electrical pulses to rapidly polarize water molecules on the filter membrane such that the water molecules are pulled to the membrane, pushing out the attached particles, which will then be removed by reject flow. Development of the system is followed by validation testing. Drexel University utilizes a flow loop consisting of: a cooling tower; a rectangular heat transfer test section with a window for visualization of crystal growth; electric heater for hot water; main circulating loop; and side-stream loop.

Potential benefits from this research include the ability to operate at a higher cycle of concentration, which will reduce cooling tower blowdown water requirements (which also reduces the amount of freshwater make-up needed). Additional environmental benefits are expected due to the reduction in the use of chemicals for scaling and bio-fouling prevention.