The Science

Curious about Granular Activated Carbon?

What is granular activated carbon?

Granular activated carbon (GAC) is carbon in a granular form consisting of natural and raw materials such as coconut shells and marula fruit stones. Heat is used to activate the carbon and this process produces microscopic pores which is readily able to capture and absorb impurities found in water.


Why is granular activated carbon used in water filtration?

Clean water is a must for good health.
Before the mid-1940’s heavy metals and bacteria were the most common threats in the public drinking supply. But now we have an entirely new group of worries in our drinking water. Some of these water hazards include polynuclear aromatic hydrocarbons, chlorinated hydrocarbons, pesticides, herbicides and trihalomethanes.

GAC has been proven to be the most effective and economical way to remove these contaminants – see the test results below

What makes GAC especially significant is the important fact that it does not remove vital minerals and salts.

Why pick a Glacier water filter?

There are three basic types of carbon filters: powered, solid and granular.

Glacier Water Systems have invested a lifetime of hard work and dedication in researching these different types and now use GAC filters as, overall, they are more effective.


While powered carbon can be an attractive option for short time treatment, it does not filter out as many chemicals as GAC and is limited in the amount of contaminants it can absorb. Therefore it becomes expensive if you want to continually want fresh, filtered water. The use of solid block carbon filters are expensive and often result in a significant drop in water pressure in the home water system and clog easily.

Glacier Water Systems use GAC as it cost-effective while maintaining a superior standard of wate filter. Cleaning your drinking water using GAC is not just smart but our unit is a little different as the carbon is infused with silver which has been proven to inhibit bacteria growth. This type of water treatment is known as Bacteriostatic Water Treatment Unit.

Are granular activated carbon water filters safe?

Safe drinking water is essential!

GAC is a well-established water filtration treatment and is the most suitable technique for home use. Although most water filters only have a life span of 6 months, the Glacier under-sink and whole house water filter life span ranges from 2 years to 3 years. However, the ability of GAC to bind and remove chemicals is used up and the water filter requires a simple replacement.

We recommend regular replacement to ensure maximum contaminant removal is achieved.

Our Glacier Granular Activated Carbon Filters

Under-sink GW1 water filter
Under-sink GW3 water filter
Whole house GW5 822 water filter
Whole house GW5 837 water filter

Our water filters can last up to 3 years! How do we do it?

Bacteriostatic Water Treatment Unit

Most traditional water filters only last for 6 months because they can not continue to absorb impurities from the water and they can be inconvenient and expensive to change. Another reason they need to be changed so regularly is because of the growth of harmful bacteria in the filter which can flow into your drinking water.

Glacier water filters are unique as they contain specially designed technology called a Bacteriostatic Water Treatment. This allows your water filter to last up to 3 years as the granular activated carbon is impregnated with silver to inhibit the growth of bacteria within the water filter.

Our water filters can remove up to 99.7% of chemicals in water!

One of the major attributes of granular activated carbon treatment is its ability to remove a wide variety of toxic compounds to non-detectable levels.

Test results for the removal of various chemical constituents before and after passing through a Glacier water filter.

Test results for the removal of various chemical constituents before and after passing through a Glacier water filter.

  Initial Concentration (ppm) After Passage Through Unit (PPM) Reduction
Aluminum 1 0.1 -90%
Ammonia 0.4 <0.03 -92.50%
Arsenic 1 0.03 -70%
Boron 1 0.9 -10%
Cadmium 1 0.01 -99%
Chloride 300 201 -33%
Chlorine 7 0.1 -98.60%
Chromium 0.1 <0.05 -50%
Cobalt 10 0.03 -99.70%
Copper 1 0.06 -94%
Cyanide 1 <0.05 -95%
Fluoride 1 1 0
Lead 1 <0.01 -99%
Manganese 0.1 0.04 -60%
Mercury 0.1 <0.001 -99%
Nickel 1 0.2 -80%
Phenol 1 <0.1 -90%
Selenium 1 <0.1 -90%
Strontium 1 1 0
Titanium 10 2.7 -73%
Zinc 1 1 0

Results were compiled by an independent EPA certified laboratory in the US.

Although the granular activated carbon water filters do not remove fluoride, we offer the GWFL water filter specifically designed to remove up to 99% of fluoride from drinking water.

  • Pesticides:
    • Simazine
    • Atrazine
    • Lindane
    • Malathion
    • Dieldrin
  • Trihalomethanes:
    • Chloroform
    • Dibromochloromethane
    •  Bromaform
    • Carbon Tetrachloride
    • Trychloroethylene
    • Tetrachloroethylene
  • Polynuclear aromatic hydrocarbons:
    • Benzo (a) pyrene
    • Benzo (ghi) perylene
    • Benzo (k) fluoranthen
    • Indeno (123cd) pyrene
    • Benzo (b) fluoranthene
  • Volatile Organic Chemicals