Scott Davis Anderson

As a Peace Corps nominee, I have been nominated for service in Sub Saharan Africa in the Water and Sanitation Extension. I have been thinking about the type of work and the environmental conditions I may be working in while serving within the Peace Corps.

I became interested in making water filters while I was interning at the Strawbale Studio in Oxford, Michigan. While creating plasters for use on natural structures, I was excited to find out how easy it was to extract clay as a resource. I was intrigued by its possible uses. I began researching ways to purify water using resources that are readily available not only on the property at the Strawbale Studio, but also in most countries around the world. I found instructions on how to create filters by combining terra cotta and organic material to create a porous clay body, worthy of filtering water upon firing. I used spent coffee grounds as the organic material that I acquired free from Starbucks Grounds for your Garden program. The fine grains of the coffee grounds burn up in the firing process, leaving behind a small porous avenue for water to travel. The filters remove pathogens such as e-coli from the water by trapping them within the pores. Colloidal silver, microscopic particles of silver suspended in water, are than applied with a paint brush to the outside of the filter. This silver solution kills the bacteria that would otherwise grow within the pores, allowing the water filter to be used over and over again.

My process began by digging up a bunch of dirt near a building site in Oxford, Michigan. I separated the clay from the sand in a large tub, by adding the dirt and water to a 10 gallon storage container.  The sand sunk to the bottom, leaving the clay on top, making it easy to skim the clay slip off the top. I placed the clay slip on top of plaster slabs to absorb the moisture, allowing the clay to dry until it became more workable. I than added the spent coffee grounds at about a one to one ratio to the clay. The spent coffee grounds added more moisture to the clay and the syrup from the coffee made the clay harder to work with, so I allowed it to dry even longer.

When I was satisfied with the clay, I brought it to a ceramic artist I met at the Ohio University – School of Art, named Bryce Brisco. Bryce is known for his fascination with local indigenous clays and was quick to volunteer his help with my endeavor. He brought to my attention a group called Potters for Peace, that has been traveling the world since 1998, teaching people how to fabricate a low-cost water filter in order to bring clean, potable water to those who need it most.

Bryce worked with the clay on a potters wheel, forming the filters into small cylinders. He was able to create 3 small filters of various shapes and thicknesses, so that I would be able to test the flow rate of the filters on varying designs. I am extremely grateful to Bryce for his contribution to this project.  He has inspired me to learn how to throw on a potters wheel. When the filters became bone dry, I began digging the pit I fired them in. 

The following is photo documentation of the firing process:

One of the three filters broke during the process. I grabbed the final filter by the rim as I pulled it from the ashes and it cracked right off. Be extremely cautious when removing the filters from the fire!  After some preliminary tests, the filters are allowing water to flow through them.  I have yet to test the flow rate, nor the purity of the water produced, but it is rumoured that one filter will produce a liter of clean water in two hours.  More testing to come!