Ancient Stone Water Filtration Technology
by Steve Herbert
During my first visit to Ecuador in 2007, I traveled to the coastal province of Manabi under sponsorship of the Ecuador office of Heifer Project International to meet with a group of local sustainable farmers to introduce dowsing and discuss other aspects of water resources development. Manabi, like much of the western coast of South America lies in the rain shadow of the Andes and is thus typically very dry. There I found the demand for knowledge of dowsing to higher than anywhere else in the country. During the same trip I had met with Ron Rivera in the capital city of Quito. Ron is the founder of Potters for Peace and the developer of the ceramic water filter. He was there to do a feasibility study for establishing a facility for the manufacturer of the filters in Ecuador. The results had been disappointing.
An ancient stone water filter sits in the lobby of a hotel in Portoviejo, Ecuador.Thus it was on my mind that other filtration methods had to be found when I went to Manabi and there in the lobby of the hotel in Portoviejo was this curious stone filter (pictured) held in a wooden frame over a ceramic vessel. The bowl was an artifact of ancestral cultures, carved from some kind of pumice stone or porous volcanic rock. When I enquired, I was told that the ancient inhabitants commonly carved these bowls and set them up to filter water poured into them. The filtration rate was on the order of that of the ceramic filters; just a small number of liters per hour. I would learn later when I left Ecuador and flew to meet Ron in Nicaragua that the acceptable range of filtration rate for the ceramic filter is one to one and a half liters per hour. Slower than that is not practical, and faster than that is less effective.
This was the problem for the ancient carvers of the bowls. The filtration rate was determined by that particular rock, and the carver could not know if the filtration rate would be acceptable until the bowl was finished. Still, it made for exciting conversation with my companions and the new dowsers of Manabi when we discussed the possibility of reviving an ancient technology and creating a cottage industry. Later I was surprised to learn that Rene Santos, director of the center for sustainable agriculture in Honduras which is my usual base of operations there, used to carve these bowls as one source of income when he was just starting his center. We had just done a ceramic water filter distribution project there, and he said he would carve a new bowl for educational purposes at the least. I look forward to seeing this on my next visit.