1. Water tank with outlet

2. Clean sand

3. Activated catalytic carbon

4. Coconut fiber (from coconut husk)

Place fiber on the bottom of tank.

Place carbon on top of fiber.

Add another layer of fiber on top of carbon

Place sand on top.

These layers can be repeated 2 or 3 times.

The material can be replaced after the filter has become dirty.

The coconut fiber possesses the best fungus inhibiting effect of natural fiber known. The fiber laid at the bottom of the water tank helps holding the activated carbon to stay in the tank and also help filter out some larger solid pieces of impurities in the water.

The better activated carbon is made from coconut shells and are not chemical activated like wood charcoal or coal; therefore it is suitable for filtering drinking water. Activated carbon is full of pores.  This network of connected pores inside the carbon creates a large surface area, about 1000 square meter per gram of carbon. Activated carbon filters out  impurities from the water by transferring the impurities from the water to the surface of the carbon. Activated carbon acts as a catalyst in chemical reaction in removing chloramine. The transferring impurities involves 2 methods:

1. Physical absorption, and

2. Chemical absorption (chemi-sorption)

The physical absorption is the gravitational force and magnetic force that pull the impurities to the pores of the activated carbon granules.

The oxidation-reduction (redox) and chemical absorption occur on the surface of the activation carbon while the physical absorption occurs in the pores of the activated carbon. The redox and chemical absorption actually change the chemicals into new chemicals. For example, the chlorin is change into chloride and the chloramine is degraded by the reaction of oxidation chemistries on the surface activated carbon.