great article! I just read about this use this morning as well:
http://www.sigmawater.com/news2.htmlGreen Home 21 Pool
Chemical-Free Sanitation
The system, called electrolytic ionization, cleans the pool by releasing silver and copper ions into the water by means of electrolysis which kill bacteria and algae.
(Water Conditioning & Purification Magazine, May, 1995 by Virginie Drujon-Kippelen)
The Herders, a Tucson-based brother/sister builders team, like to think of their prototype, Green Home 21, as the home of the future, "a blend of a healthful, smart and environmental home."
Indeed, the 4,400 square-foot home features a varied array of automation management, energy-efficient construction methods, healthy materials like non-carcinogenic wall insulation (newspapers) and non-toxic carpeting made from recycled materials (plastic soda pop containers).
As another environmental smart option, the builders have chosen a chemical-free system to sanitize the 10'x15' pool.
The system, called electrolytic ionization, cleans the pool by releasing silver and copper ions into the water by means of electrolysis which kill bacteria and algae. By reducing the need for pool chemicals, the system is recommended as an environmentally sound alternative to chlorination.
In the case of Green Home 21, the ionization system allows the back flush pool water to be used in the greywater recycling system. Ionizer manufacturers claim the system eliminates the side effects of chlorine, such as eye and skin irritation or allergy.
According to Tom Colosimo, president of the Phoenix-based ionic water purification company who maintains the pool water system for Green Home 21, "bathing in water that has been purified through an electrolytic ionizer is like bathing in bottled water. It has no taste and no odor."
Ancient Civilizations Used Sanitation Methods
Copper and silver have a complementary action on water sanitation. On one hand, silver purifies water by killing bacteria (it is also known to be an effective disinfectant in the eyes of newborn children and is used for the treatment of burns as an antibacterial agent). On the other hand, copper is a strong algaecide which kills fungus.
The benefits of copper and silver have long been known. "Greek historians wrote that Cyrus the Great, King of Persia, carried water in silver flagons on his various military expeditions to keep the water fresh," wrote John D. Collins, from Ionics, Inc., a water conditioning equipment manufacturer and bacteriostatic softener, in a February 1994 WC&P article. More recently, in this country, settlers moving across the American West would place silver dollars and copper coins in their water to purify it. The movement of the wagons would cause the coins and dollars to rub the bottom of the casks where the water was stored, causing the release of ions.
With the advent of electricity, ionization is now created through the process called electrolysis, the passage of electric current between two electrodes. A copper and silver ion generator releases controlled quantities of copper and silver ions into the water from two copper electrodes impregnated with silver. The electric current causes the migration to charged ions to the positive and negative electrodes. In the water, those charged particles alter the electrostatic nature of bacteria and algae, causing them to floc together. They are ultimately removed by the filter.
Pros and Cons
An often-cited advantage of using copper and silver ions to sanitize water is that, unlike chlorine which evaporates from the water, they remain in the solution until they have been effective. Ionizer manufacturers also point out that ionization minimizes the use of acid to maintain pH balance, because of the chemical-free environment created by the method.
However, Elissa Sard Pollack in a June 1994 Aqua article said that "as with any water treatment system, ionization can cause problems if it's misused. Water balance factors - pH, alkalinity, hardness - must be maintained, and the pool should be kept free of debris." She also pointed out that the most common problem associated with ionization is staining, usually on plaster pools.
The stain is a blue-green color caused by extreme water balance problems and/or extreme over ionization.
Ultimately, copper and silver ions are ineffective for removing organic matters such as hair, skin, body oil, lotion, urine, food and makeup. The process of chemically eliminating organic matters is called oxidation. Copper and silver ions act only as sanitizers; they eliminate microorganisms (microscopic-sized celled animals), but do not act as oxidizers. This is why chlorine or other disinfectants are often needed to complete the cycle of disinfection (using ozone gas generated can also be used as an effective oxidizing and disinfectant process to destroy organic contaminants and kill bacteria as well as viruses).
A Bright Future
Although ionizers have been on the market for more than 20 years, most people who enjoy residential swimming pools use chlorine as a disinfectant, said Mr. Colosimo. He said this was largely due to a lack of publicity by the ionizer manufacturers.
"We didn't take the time to advertise our products. People just don't know that our systems exist and work," he said. Moreover, he added that ionization systems require less maintenance work and pay for themselves in two to four years.
From a marketing standpoint, this could mean that ionizer manufacturers have a bright future ahead with a burgeoning market ready to explorer.
References
Elissa Sard Pollack, "An Ion Acquisition,"
Aqua, June 1994.
John D. Collins, Silver’s Role In Water Treatment," WC&P February 1992.
Wayne,J Ivisich, "Using Chlorine to Treat Pools & Spas," WC&P June 1994.
Alden Coke, President of Aqua Flo Inc.
Virginie Drujon-Kippelen is a freelance journalist from France.
She holds a master's degree in journalism.