To the editor: Nigel Calder’s recent article on watermakers (“Watermaker installation and maintenance,” July/Aug. 2007) was very well researched and informative. However, in a side bar Nigel indicates that the Spectra Z-Guard and Z-Brane are less than effective according to “others in the industry” because “the effect of the electrostatic field is short lived, after which the water reverts to its natural state, rendering the system ineffective.” Spectra and others disagree with this inaccurate assumption and would like to explain how the system works.
As water enters the membrane it is exposed to a powerful electrostatic field of an electrode charging all water molecules in a positive orientation. This positive charge prevents particulates from bonding to one another, preventing the formation of sludge, scale and biological fouling. The wetted charged surfaces form a strong boundary layer preventing particles from attaching. Bacteria are rendered inactive and unable to absorb nutrition to replicate into colonies.
Spectra’s system is designed to charge the water 24/7, preventing it from reverting to its original state. Continually charging the water in the membrane will prevent biofouling and scaling from occurring, thus protecting the membrane. The Spectra Z-Guard is designed for chillers and air conditioners, while the Z-Brane is specifically designed for RO watermaker systems. Both units consume approximately 100 mA of power at 12 volts DC.
To some it seems a little like “black box magic,” however, this technology is not new and has been used for years by huge companies like AT&T and Bethlehem Steel in cooling towers, chillers and other systems, saving substantial amounts in maintenance costs over conventional acid cleaning and de-scaling.
Ray Carter is sales manager for Spectra Watermakers in San Rafael, Calif.
