Bacteriostatic Activated Carbon – Silver Impregnated
Bacteriostatic Activated carbon, often erroneously called antibacterial carbon, inhibits microbiological growth and biofilms inside activated carbon filters . Activated carbon traps organics which can become a food source for any microbiological flora.
Activated carbon filters for rain water filtration should be bacteriostatic carbon, alternatively they can cause more harm than good. Severe waterborne illnesses can result from activated carbon filters that harbour bacteria .
Silver occurs naturally in the environment, mainly in the form of its very insoluble and immobile oxides, sulfides and some salts. Because silver ions are bacteriastatic, silver is used both as an emergency drinking water disinfectant and impregnated in some water filters to prevent microbial regrowth.
The specific antibacterial mechanism of silver is not clearly understood, but research with E. coli and S. aureus has shown that silver treatment of these microorganisms has resulted in DNA losing its replication ability.
Research on drinking water disinfection systems has shown that silver can be used successfully to control bacterial growth. It has also been found that the addition of copper and silver to water systems may allow the concentration of free chlorine to be reduced while still providing comparable sanitary quality of the water.
Still other research has shown that silver can be used in hospital water systems to control Legionella and in cooling towers to control bacterial growth. Silver has also been used to enhance the effectiveness of ultraviolet (UV) radiation in inactivating viruses in water. Also see : https://www.watertechonline.com/silver-copper-have-anti-bacterial-effects/
How does Silver inhibit microbial growth ?
When copper and silver ions and nanoparticles are released into water, these cations (positively charged) are a potent microbiocide. These ions bond with negatively charged areas on the microorganism’s cell walls, affecting cell wall permeability and minimising the intake of life-sustaining nutrients.
Inside an algae cell, copper and silver attack sulfur-containing amino acid radicals in the proteins used for photosynthesis. Photosynthesis and reproductive processes are blocked, leading to cell lysis (disintegration) and death.
The greatest benefit of copper and silver is that they remain active in water, providing long-term residual, non-toxic protection against recontamination. They remain in water until they flocculate, or form masses with algae and bacteria and then become large enough to be removed by filtration.
One advantage of silver ionisation is that both substances are retained in trace amounts in the water and continue to have an antimicrobial effect over weeks and months. Even after the ionisation system has been switched off, the effect persists.