Because our water supplies are affected by multiple factors (pollutants, air particulates, runoff, decomposition or organic materials, etc.), they could contain:

• Suspended particles (such as sediment, sand, rust, cysts, algae and other undissolved matter).
• Harmful or problematic metals (such as iron, lead, mercury, copper, nickel, chromium, etc.)
• Organic and inorganic contaminants (such as chlorine, volatile organic compounds, pesticides and herbicides, MTBEs, etc.)

For this reason some waters need to go through multi-stage filtration to effectively extract all levels of contamination. Some water supplies contain several of these agents, and public water agencies will treat to remove them.

If, however, there is concern about a water supply and/or if one has a well subject to contamination, such as from surface leaching, more aggressive filtration may be desired.

Adding to carbon
A single medium such as carbon or another type of single-stage filtration can often be used. Often, a non-bituminous medium, such as high–grade coconut shell carbon, provides a greater volume of micropores, making it more effective in removing contaminants.

Carbon filter types, if used alone, will be depleted after using up their capacity for removing chlorine. Redox media can remove chlorine before it reaches the carbon filtering agents so that the life of the carbon can be extended and allow it to deal more effectively with organic/inorganic contaminants.

By incorporating high-purity copper-zinc redox media technology into other stages of filtration, a water treatment system gains increased capacity to protect against harmful pollutants by changing them into harmless components, with better results and economy.

Redox principles
Redox media technology is based on electrochemical and oxidation-reduction (redox) principles.

A high-purity alloy combination of two dissimilar metals — copper and zinc — in the redox process creates an electrochemical reaction in which electrons are transferred between molecules, creating new substances which are oxidized. This changes some contaminants into harmless components.

Chlorine is changed into a non-harmful, water-soluble chloride, which then travels safely through the water supply.

Similarly, a high-purity copper-zinc redox medium, by acting as a catalyst, changes soluble ferrous positive ions into insoluble ferric hydroxide. The ferric hydroxide then is easily filtered and removed by backwashing that is automatic in multi-stage non-cartridge filters.

Also in the same manner, heavy metals such as copper, lead, and mercury react through the electrochemical changes, are attracted to the surface of the media, and are easily removed from the water system by the occasional backwashing stages of filtration.

Energy potential
The energy that is needed to remove contaminants is a natural occurrence due to the electrochemical and catalytic potential of the copper-and-zinc redox alloy. This makes this type of redox medium highly effective in many water treatment applications, including dechlorination, removal of dissolved heavy metals, and iron removal.

Oxidation-reduction potential (ORP), calculated in millivolts (mV), is a measure of the readiness of a substance to part with electrons.

Metals, including copper and zinc, can be found in standard tables showing the relative reactivity of metals, often listed in descending order of reactivity. In such tables, zinc is at the more reactive end and is a more electropositive metal than copper. Copper is in the highly unreactive group.

Copper in this media becomes the permanent cathode and zinc is used as the sacrificial anode. Zinc is the electron donor. Zinc has a value of –0.76 volts and copper +0.36 volts, creating a 1.1-volt difference.

High-purity copper and zinc provide the most effective combination of metallic alloys, providing redox potential for water treatment and purification. The ORP quickly changes from +200mV to -500mV with one pass through this filter media.

Multiple applications
The redox media is in the form of granules which, when used with various carbon or inline filters, protect the carbon bed from bacterial fouling.

The stages of water purification will vary according to the unique characteristics of an individual’s water supply.

Redox technology can be incorporated into whole-house, reverse osmosis (RO), deionization (DI), and ion exchange systems for effective water filtration.

Whether one’s water filter needs are for suspended particles, harmful chemicals and heavy metals or organic/inorganic contaminants, multi-stage filtration in many combinations with redox technology can provide a much-improved water supply.

Editor’s note: The combinations of filter materials referred to above do not represent a specific filter and, as such, there is no claim being made that any random combination of these materials has the ability to remove the contaminants described here.