WASH Technologies - Ceramic Filters

A ceramic water filter is a simple, bucket-shaped (11” wide by 10” deep) clay vessel that is made from a mix (by weight) of local terra-cotta clay and sawdust or other combustibles, such as rice husks.


The filters are formed by using a press. The simplest press utilizes a hand-operated hydraulic truck jack and two-piece aluminum mold. Filters are fired to about 860 deg. C. and the milled, screened combustible material burns out, leaving porous clay walls. 

The filters are tested to make sure they meet a standard rate of filtration and then they are coated with colloidal silver. The combination of fine pore size and the bactericidal properties of colloidal silver produce an effective filter.

The ceramic water filter has three parts: a plastic container fitted with a spigot; the ceramic filter insert; and a lid fit to the ceramic insert. The filter weighs about 8 pounds and is the size of a 5 gallon utility bucket. Contaminated water is poured into the ceramic insert which purifies the water for drinking as it seeps through the insert into the plastic container. The flow rate ranges from 1 to 3 liters per hour, which provides adequate safe drinking water for up 6 people for at least 5 years. Safe water is easily poured by any family member from the easy to use spigot.

How does the filter pure filter work?
When contaminated water is poured through the ceramic water filter, it is purified in three ways:

A pore size of 1.3 microns filters out turbidity, larger bacteria and parasites
Colloidal silver creates a hostile environment for bacteria, breaking down the cell membrane as it passes through.
One half inch of activated charcoal integrated into the core of the filter improves taste,odor, and color.

The technology of the FilterPure ceramic water filter is simple, effective, and, sustainable. A round-bottom ceramic pot is made from a mixture of clay, a combustible material (sawdust or rice husks), and silver. After the clay and combustible have both been sieved through a fine mesh, they are mixed together with a measured amount of silver and water until a homogeneous mixture is formed.


The mixture is then molded into filters using a filter press, which are slowly dried and kiln fired. During the firing process, the combustible material is burned out leaving micro pores coated with the silver to clean the water. During the firing process, about ½ inch of charcoal is produced within the filter core which further improves the water.