Yesterday was an eventful day at the factory. The production kiln with capacity for 50 filters was fired for the first time and the foundation for the 60,000 liter rain water storage tank was poured. These two events are the culminations of many days of works this January and before. From preliminary results in looks like both events were successes.
The production kiln is made of red brick and is amount the size of a big closet with a 15 foot (from ground level) chimney attached. It was custom design and build by Manny. I think I have mentioned Manny before, but as a reminder, he is an expert ceramicist, previously a professor as well as an industrial designer. He has an incredible sense for how to design and construct nearly anything. Because of this ability, we are constantly asking him for help with the myriad of different projects going on at the site. To prevent him from getting distracted while he trained the factory manager in the ways of the kiln yesterday, Susan told made a morning announcement that any questions for Manny should be directed to her for the day and she would write them down until the end of the day.
The firing process is quite delicate. It took nearly 10 hours and started with a low temperature pre-firing, which helps remove all the moisture from the pottery to prevent cracking during the actually firing. Once black smoke billows from the chimney then the actual firing can begin. There are two goals with the actual firing - to have as even a distribution of heat as possible and to reach 900 Celsius. At 900 degrees, the tiny pieces of rice husk that are in the clay mixture incinerated leaving microscopic holes that allows the water to filter through. Even distribution of heat is important to make sure that all the filters come out as standardized as possible. The kiln, as you might expect, is powered by a wood burning below the main chamber. Mitch, Stephen, and I cut into 2 foot sections and weighted all the pieces that went into the firing. We estimated the total amount of wood, so that we can figure how much each firing costs. We have some final measurements to do today, but I expect nearly 350 kilograms (or about 770 pounds) of wood was used in total.
The other major event of the day was the pouring of the multiple layer foundation for the massive rain water storage tank. The goal of this tank in conjunction with the gutters on the west side of the roof is to catch and store nearly 60,000 liters of water during the raining season to be used as the source of water for the site. When we arrived on the site on the first day, we were greeted by a massive hole - 6 ft deep, 15ft wide, and 20ft long approximately. From there, a foot deep trench (from ground level 7 feet deep) for the exterior wall of the the tank was dug, an elaborate rebar structure for support was bended and placed, forms for the pouring were made, a center 4 inch pole was erected to support the roof as well as ensure that the tank is nearly perfectly circular. And as of last night, the foundation for everything was poured.
Pouring the foundation was quite the endeavor. First it involved pouring and filling the entire circular trench, then required a 3 inch layer across the entire tank, followed by a 6 inch raised and foot wide exterior lip for the concrete block wall to rest on. All of this concrete had to be poured at once to prevent cracking and breaking. I'm sure my description of the design is confusing. Hopefully once I can post pictures those will help to clarify what I mean. Due to some unexpected scheduling delays, we weren't able to start poring until nearly 3 pm yesterday. Once we started there was no turning back.
We had quite the crew partaking in this production. Stephen, Mitch, Shanti (a graduate student), and myself were there along with nearly 10 of the factory workers, and Frank - a local expert in these type of tanks. We set up a conveyor belt line of people. 3 or 4 of the laborers backbreakingly mixed the concrete by hand, then filled buckets. Those buckets were carried by 4 or 5 more people to the hole. From there the buckets were passed to down into the hole and transferred another few sets of hands before being poured where needed. While I don't know (yet) the number of bags of cement used or the total volume of concrete poured, I do know based upon my soreness that it was a lot.
While the work was physically tiring, the attitude of everyone made the experience great. Everyone had a positive, can-do attitude and there was plenty of laughter to keep spirits high. Once it got dark, the only sources of light we had were the high-beams of a truck, a few headlamps, and a full moon. This experience will definitely be one that will stick with me. A few months ago, I never thought (literally the thought never even crossed my mind) that I would ever be pouring concrete under moonlight in rural Ghana. Now that I have done it, I can (add and) cross it off my bucket list. Check!