Voltea – Desalination Innovation

In 2007 EMF joined the Voltea team working on a new desalination technology, called Flow Through Capacitator (FTC). Voltea is a limited company in the portfolio of Unilever Ventures, UK (www.Voltea.com).
FTC was invented by Marc Andelman in the USA and his company was purchased by Unilever Ventures.
Since 2006 the technology has been further developed by Unilever Ventures and will be in the market by 2010.

FTC Technology

FTC removes ions (i.e. dissolved salts such as sodium, calcium, chlorine, nitrate and arsenic) from a variety of water sources ranging from tap to brackish ground water. The technology uses little electricity, has high water recovery and does not need any chemicals for regeneration.

A typical cycle of FTC operation is depicted in Figure 1. The FTC cell is represented in a simplified way, only showing one pair of electrodes and one pair of ion selective membranes. Water containing salt enters the FTC cell from the left. Positive and negative ions are attracted to the negative and positive electrodes respectively and are stored on the electrodes. Water leaves the FTC cell with a significantly reduced ion concentration. Depending on the flow rate and the initial salt concentration of the feed water, the salt concentration can be reduced by up to 98% with FTC.


Figure 1  Schematic representation of the operation of FTC technology.

During the desalination step, ions build up on the electrodes and at a defined point the electrodes have to be regenerated. This is achieved by reversing the polarity of the electrodes so that the stored ions move away from the electrodes. As a result the ions become trapped in the flow compartment between the ion selective membranes. In the final step of the FTC cycle, the FTC cell is flushed with water and the ions are removed in a small volume waste stream.

The advantages of FTC, compared to competing water purification technologies, differ according to the application and the properties of the feed water.    FTC:
 

• Removes all ions effectively, including problem ions such as nitrate and arsenic
• High water recovery, up to 95% (much high than RO (<70%))
• Less susceptible to bio fouling, particulates and scaling, this eliminates one of the main drawbacks of RO and ED
• Easily scalable from very small to large giving it in a wide range of applications
• Efficient operation at low pressure and high water temperatures where RO only works at high pressures and not effectively above 40oC
• No chemicals required for regular operation which reduces operational cost and environmental pressure
• Low energy consumption, up to 5 times lower than RO using energy recovery

2 Market Opportunity

Ion removal from water provides benefits in many applications and market sectors.  Benefits include:

• reduced corrosion and scaling, which improves process efficiencies and extends service life of equipment;
• improved detergent functionality, which reduces chemical and energy use;
• removal of toxic compounds, which provides safe drinking and process water.

Initial market entry will focus on three significant market sectors, industrial, domestic appliance, and residential water treatment.