Description of Challenge
Every year 1.7 million people, mainly children under the age of five, die from diarrhea which is caused by unsafe water. The objective of the Potters for Peace Water Filter Project is to make safe drinking water available by helping set up workshops that produce ceramic water filters made from local materials. These filters are low-tech, low-cost and eliminate turbidity and approximately 99.88% of water-born disease agents.
Solution
The Ceramic Pot Water Filter is a simple, bucket-shaped (11” wide by 10” deep) clay vessel that is made from a mix 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.
When in use, the fired and treated filter is placed in a five-gallon plastic or ceramic receptacle with a lid and faucet. Water passes through the clay filter element at the rate of 1.5 to 2.5 liters per hour, providing enough safe drinking water for a family of six.
Pricing for ready-to-use filter units, including the receptacle, is determined by local production costs and is usually between $15 to $35. Replacement clay filters will cost $4 to $6. A basic production facility with three or four workers can produce about fifty filters a day.
