Tuesday, October 11, 2011

Potters for Peace

One of our primary purposes for staying in Managua was to visit with Robert Pillers of Potters for Peace and to tour their filter factory located in San Marcos.  Mike's master's thesis was related to ceramic pot filters (if you are bored enough to follow that link, make sure you click on the link at right underneath "Available without purchase" that shows "Full Text - PDF") . He studied the effects of water quality on the nano-silver coating applied to ceramic water filters. During his studies, Mike had the opportunity work with Robert Pillers while compiling a Best Practices document for manufacturing ceramic pot filters. It was an honor to meet Robert in person and tour the Filtron production facilities.

Clean Drinking Water & Ceramic Pot Filters
Nearly 1 BILLION people on earth are estimated to lack access to clean drinking water, and that number is often considered to be a low estimate (particularly because numbers reported by development agencies are often inflated to show that they are accomplishing what they set out to do, and to keep their channels of funding open).  Water borne diseases are directly responsible for over 3 million deaths per year, with children under 5 years old accounting for the largest majority of those deaths.  In fact, nearly 1 in 5 child deaths worldwide is due to diarrhea.  An illness that is little more than an inconvenience for most of us reading this blog is life threatening for those lacking the knowledge and resources to combat it.  While health effects are a strong justification for improving water (as well as sanitation and hygiene) conditions where needed, there are also substantial economic gains when those interventions are successful and sustained (that's the hard part).  Further than that, there can be a huge improvement in the overall well-being of the individuals within that community.  That change is worth a lot, but not easily measured.

There are effective and inexpensive technologies to improve access to clean drinking water, including interventions at the household level (see this report for more details).  These technologies include boiling, chlorination (using readily available bleach), solar disinfection, biosand filtration, and porous ceramic filtration, among others. 

One popular type of filter is the ceramic pot filter.  There are currently over 30 factories in 18 countries producing ceramic water filters, all targeting a cost to the end user of US$ 10-20.  Potters for Peace has been promoting the production of ceramic pot filters since 1998 after responding to a dire need in Nicaragua for effective and inexpensive water treatment products in the aftermath of Hurricane Mitch. 

The operation of the filter is simple:  remove the lid, pour water into the ceramic filter element, then allow water to trickle through the filter element down into the receptacle (in this case the clean bucket) and out through the spigot.

(picture of actual ceramic pot filter resting on receptacle with spigot as well as schematic of recently filled filter, with water beginning to pass through the filter element shown in brown)

To produce these filters, dry clay is mixed with an organic material like sawdust at a controlled ratio...

(Robert and Jill in front of the raw materials storage)

...then mixed with water to make the clay workable, so that it may be pressed into shape...

(Mike pulling the jack under the molds to press the filter)

(kicking the jack out after pressing)

(Mike's first pressed filter)

...after being pressed, the wrinkles from the plastic bags are smoothed and the wet filter is inspected for obvious defects before it is allowed to dry.



Once dried, the filters are loaded into a kiln to be fired into the final ceramic product. The temperature during the firing process is carefully controlled up to its peak temperature of around 850 degrees C (1560 degrees F) to drive off the remaining water and to burn off the organic material (sawdust), leaving behind little tiny pores that will filter the water.

(6 kilns capable of firing 50 filters each)

(some of the insulation on the door was blasted off during the firing process, so some kiln design changes are underway)

(it takes about 1.5 carts this size of wood per firing)

(kiln during firing)

Final quality testing is performed on the filters before a colloidal solution of nanoparticle silver is applied to the entire surface of each filter.

(flow rate testing to make sure each filter qualifies)

(discard pile of rejected filters)

There is a lot of good information regarding ceramic water filters on the interwebs, including the Potters for Peace filter page (see links at right), RDI-C, IDE, Thirst-Aid, and other general appropriate technology websites.  For more general water and sanitation facts, check out the water.org website.

We joined Robert for a marvelous dulce de leche milkshake at a biker friendly cafe to round out the afternoon.

No comments:

Post a Comment