Clay Pot Water Filter
The AW ceramic water filter has passed through many transformations in a short time as the Lao partners adapt the innovation to their traditions and marketplace. Initially, pots were small and hand-formed so the potter could master the technology. The primary consideration in these early stages was filtration rate, so that the pots were able to produce enough water clear of fecal matter/bacteria. In achieving this, the potter began to focus on increasing the flow-rate to enable the CPWF to produce adequate quantities of water for domestic use. Once the manufacturing issues of quality control and repeatability were resolved a feedback team of Lao potters and villagers were consulted and began to advise us on a design and form of filter that suited the Lao village conditions.
Initially the filter was in the form of a ceramic water filter bowl sitting inside a water receptacle. However, after receiving advice from the feedback team, this has given way to a ceramic water filter candle that is fitted with a rubber thong gasket inside a bucket, sitting on top of a storage bucket. This latest redevelopment of the filter is easier to reliably manufacture and allows for greater water pressure and increased water flow. It can be made by hand, and because it is smaller than a bowl or bucket-shaped filter, is easier to fire. Firing is achieved in an outdoor fire with the candle filters stacked on a mesh base, burnt in a fire fueled by rice straw and sticks. The technique does not require a kiln, uses freely available material, and is very low cost. Temperatures are controlled at between 800 and 900 degrees Celsius for approximately 2 hours.
The latest iteration of the clay-pot water filter produces a candle (cylindrical) filter that uses commonly available and cheap plumbing fittings to connect to hoses and pipes. This enables this system to perform effectively in both gravity-feed and syphon applications, in homes as well as in schools.