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Mechanical Engineering undergrad student Zachary Kline volunteered in Kokland, Uzbekistan for ten weeks this summer developing sustainable water purification systems. Zachary worked with Joint Development Associates International (JDA) under the supervision of Beat Grimm, a Swiss Mechanical Engineer working for JDA who lives in Uzbekistan. The third member of his team was Dave Norton, an active Engineers Without Borders student member from Syracuse University. Zachary and his team worked on designing and then building two prototype solar water purifiers.
The JDA office in Kokand runs an educational program advocating SODIS (solar disinfection), a program invented by the Swiss government which uses ordinary plastic soda bottles to disinfect drinking water. The theory of this program is based on the concept that if a bottle of water is left in direct sunlight for a few hours so that it reaches 50 degrees Celsius, the heat and solar radiation combined are sufficient to kill any biological contaminants.
Zachary and his team worked on a side project to create large-scale purifiers that would supply a school or hospital with clean drinking water. One such purifier already exists in El Salvador, but cost $1000. The goal of Zachary?s team was to produce a similar unit that would purify 200 liters of water per day and cost $150 or less.
Zachary and his teammate Dave Norton worked more or less independently, running their ideas by Grimm but doing the majority of the legwork. They eventually decided on two different concepts, one with a layer of water sandwiched between sheet metal and glass (similar to the unit in El Salvador) and another in which the water passed through glass tubes created from fluorescent light bulbs.
?The lack of materials was the most difficult part of the project,? says Zachary. ?We wanted to use exclusively locally available materials to keep the cost down, but that severely limited our options. For example, we wanted to use copper piping in a counterflow heat exchanger to preheat the water before it entered the solar collector, but copper is a controlled substance in Uzbekistan. The government owns all mines in the country, including copper mines, and all copper produced in Uzbekistan is exported. In order to obtain copper piping, you need to buy it from someone who imports it legally, and obtain proper documentation in order to possess and transport it. If you were to be stopped at one of the regular police checkpoints with copper piping in your truck and not the proper documentation, you would be imprisoned for smuggling. Aluminum is similarly controlled. Because of these difficulties, we were not able to obtain copper piping until the very end of the summer and were unable to complete assembly of the prototypes. The plans are complete, but assembly is not. Eventually Grimm will complete the assembly. A local factory expressed a desire to mass produce the purifiers should the prototypes prove effective.?
?Other major areas of difficulty were finding a temperature-sensitive valve which would not allow water less than 50° C to pass through the system. We could not find a locally available valve with a less than 25° C hysteresis (difference between opening and shutting temperatures), which was obviously unacceptable. We finally ordered a mechanical valve from Germany, which unfortunately cost $60 per unit. A battery operated valve is also being considered. The other major problem was leaks, as caulks and epoxies are also unavailable in Uzbekistan. Most of the joints in the system are either welded (both plastic and metal welds) or soldered. Designing joints to transition between materials (plastic to glass, metal to plastic) was extremely difficult.?
?It was a fascinating summer both in terms of the work and the cultural experiences. Dave and I stayed in an old Soviet apartment complex which was about a fifteen minute walk from the office. There was no running water during the daytime and no hot water ever, and the apartment was regularly around 90° F. I woke up every morning to the cow mooing below my window or else the extremely hoarse rooster which crowed pretty much around the clock. At night we would often play frisbee with the local neighborhood children, who had never seen a frisbee before.?
?Much of our working time was spent traveling with our interpreter to local craftsmen (carpenters or welders) to get specific parts fabricated. They were unfamiliar with technical drawings, so we had to rely almost exclusively on 3-D sketches and then supervise the entire process.?
?Things move much slower in Central Asia. If it was a large part that we had fabricated, we would first pay the craftsman from our backpack of cash. There are 1000 Uzbek soum to the dollar and the largest available note is the 1000. We had to work with 200 soum notes most of the time, as currency is just not available. Then we would hire a horse-drawn cart to carry the newly fabricated part and ourselves back to the workshop.?
?The extreme hospitality of the Uzbek people also amazed me. We were invited to the wedding of the daughter of one carpenter we frequented. I was also amazed at the frequency with which craftsmen would not charge us for work they had completed. They were obviously extremely poor and could use any money at all, but would not accept payment for their services since we were foreigners.?
January 15, 2005
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