Hi, Raphael speaking....
Here's some info about the last achievements at the pottery.
We've modified the kiln according to this drawing. This has reduced the number of pots we can burn at a time (around 30 now, against 50 prior to modification) but greatly ameliorates the repartition of heat during firing and allows to better control temperature. Pots now look very similar after burning. We've been able to reach 850°C (measurement in the middle of the kiln) and get rid of the black core in the pots. One concern though: the inside of the pots still seem slightly unburnt (lighter colour than the outside and presence of rice husk)...
In the last weeks, we've sourced 10 types of clay in different settings located in Kilombero district. Here's some images of sample tiles we've made from these in the last weeks (here ready to burn in the kiln). Other pot production has stopped in the last weeks, as we first want to define the type of clay we want to work with and are still waiting on the molds to arrive so as to make the first tests with the press.
Marco the new swiss volunteer from Switzerland has arrived in Ifakara late February and will look after the pottery project together with Bruno our local manager. We've spent about a week together and he's quickly taken grab of the project. I wish you all the best Marco!
I've returned to Switzerland last week-end and am now back to design and scenography... Was great to meet the new staff and see everyone again. Crazy how fast this project evolves! Keep it up guys!!!
Last last week we commenced testing on a batch of 15 filter pots produced from the kiln post modifications. The result from the first pot testing is out and is very encouraging. The pot removed 85% faecal coliforms. This is without any silver nitrate addtion - so I would expect well above 90% removal with silver nitrate.
We were also interested to test the ability of the pots to remove iron, after we had feedback from one of the potters that she could not taste iron after she had used it on iron rich borewater. We used water from the Mapinduzi Primary School which had a raw iron content of 0.87 mg/L. Note at this level the water is safe though suffers from a metalic taste (up to 3mg/L considered safe). After filtration through the filter pot the iron level recorded was 0.45 mg/L - a greater than 50% reduction in iron! This is an unexpected and exciting result!