All Eli and I could do was laugh. It had taken time and a lot hard work, but now we had clean, clear water flowing from a biosand filter. With a glowing smile, Eli announced, “Now, I know why we do this.”
Week 3 began with making some changes to our mold and sieving a lot of gravel. By a lot, I mean a truckload. It was undoubtedly hard but very, very important. While the sand in the filter kills the pathogens, gravel ensures the sand doesn’t end up at the bottom of the filter and clog the outlet tube. To prevent this clogging, you need two layers of different size gravel - hence the hours of running rocks through a sieve. While the sievers-in-chief were Eli and I, we did have some help.
Monday afternoon, two men, just back from farming, joined in. One of the villagers saw his ten year-old son and signaled him to come help. Although he looked exhausted, every child in Tordzinu under the age of 12 was watching us sieve, and the man’s son clearly enjoyed the attention. As it got closer to evening, I told the villagers that they could stop and I went to check on mold construction. I came back five minutes later to find every kid in Tordzinu sieving gravel. A few older girls were shoveling gravel and dumping it into sieves; three kids easily under eight were putting gravel into a headpan and passing it to another two kids to take to the sieves; and teams of three to four were operating each sieve. To say the least, I was shocked. The kids of Tordzinu had turned pretty difficult and monotonous work into an afterschool game – and did so with a considerable amount of coordination and teamwork.
Tuesday and Wednesday, we made more molds, brought sieved gravel to Dorkplorame, and poured filters in Dorkplorame and Tordzinu. Then, we disassembled the molds and the next step of filter production: washing sand and gravel.
To villagers passing by, we looked absolutely ridiculous. Despite the oddity of it all, this is an integral part of making a working filter. You need to wash gravel to prevent the outlet tube from clogging. Washing sand removes fine silt particles. Silt controls the speed of water flow like the accelerator and break controls the speed of a car. Less silt equals a faster flow of water out of the filter, and vice versa. However, remove too much silt and the water that comes out will not be clean. So, it is a delicate balance.
After we washed the sand and gravel, we put it in one of the concrete filter boxes. We began running water through. At first, the water from the filter is generally pretty dirty. All you can do is keep adding water to the top. After a while, I asked Eli for an empty bottle and stuck it under the outlet tube. As the water kept flowing, we saw that it was clean and clear. Filter number one was complete. Kelvin grabbed the bottle and videoed himself drinking some and Eli began filling up a container to take home.
We proved to the villagers that this does work and garnered some enthusiasm when we showed everyone who passed by. We are now ready to move forward and spend the next two weeks focused on training and expanding filter production.