<p>Access to clean drinking water has long been an issue in the developing world, and the <br />impacts of unclean water on these communities cannot be overstated. A crucial component to <br />saving lives as well as improving quality of life is water disinfection. However, this problem is <br />made difficult by the fact that for water systems in developing countries, particularly rural ones, <br />there is a lack of access to the same funds, testing equipment, and electricity that make water <br />disinfection feasible in developed nations. As a result, a creative solution must be utilized to <br />achieve water disinfection in these communities. This is where the Calvin Clean Water Institute <br />comes in: combining knowledge across a wide variety of disciplines to help solve these <br />problems. We bring our academic understanding and work with knowledgeable locals to help <br />develop creative solutions to complex problems.</p>
<p><br />The goal for this year&rsquo;s research was to investigate, with the future goal of implementing, <br />a passive (non-electric) chlorinator that could be used in a small (less than 500 home) <br />Ecuadorian community. Preliminary research indicated the suitability of the CTI-8 chlorinator for <br />this undertaking.</p>
<p><br />The CTI-8 chlorinator was chosen because it could be constructed easily out of PVC, <br />was inexpensive, and could dispense chlorine consistently. As a result, we began our research <br />by building the chlorinator and a model system to test it in. Afterwards, we began collecting <br />large quantities of data about the chlorinator to understand its operation and capabilities. To do <br />this, the flow rate of water through the model system was varied, as were other parameters to <br />determine the behavior of the CTI-8. The effluent chlorine concentrations were measured using <br />a DPD pillow and a visible spectrometer. We learned that by varying the chlorinator bypass an <br />operator can effectively exert control over the chlorine concentrations. For implementation in a <br />community, this can prevent microbial contamination while maintaining low enough <br />concentrations to prevent community rejection. This was a crucial lesson that will most likely be <br />used in the future implementation of chlorinators, including a possible passive chlorinator <br />installation in Spring of 2024.</p>
<p><br />A secondary component of my research was the use of electrolysis to create bleach,<br />and to design a procedure for container disinfection with the synthesized bleach solution. This <br />ended up being the less successful portion of the project but still led to important developments <br />for future research.</p>
<p>The electrolysis system was comprised of an electric current that was run through a saltwater <br />solution for 24 hours, which results in a concentrated bleach solution. Several trials were run, <br />with the intent to create a concentrated bleach solution. Although none of the trials produced the <br />original target concentrations, modifications in the process resulted in a marked improvements <br />as the summer progressed. </p>
<p>Although I succeeded in meeting the goals that my advisors and I set for summer research, <br />there were significant setbacks along the way. It took days to begin collecting reliable data for <br />the chlorinator due to an unexplained spike in chlorine concentrations, and the electrolysis <br />produced unexplainably low bleach concentrations.<br />Overall, research was an incredible experience. The most important lesson I learned from this <br />project is that the solution to any real-world problem is extremely complex. As engineers, we are <br />prone to the sin of pride, where we think we have the answers necessary to solve every <br />problem. In reality, real world problems are necessarily complex and multifaceted, and problems <br />that are worth solving can require weeks, months, or even years to develop adequate solutions.</p>

<p style="text-align: justify;">In 2002, WHO reported that nearly 1.7 million deaths worldwide were caused by unclean <br />water. The risk of death by unclean water is elevated for young children, for which the second <br />cause of death worldwide is diarrheal disease, which is largely caused by microbes; these <br />microbes, when unaddressed, can proliferate in drinking water. Health risks are further elevated <br />in rural communities, which often lack access to the technology necessary to treat water for <br />microbial contamination. This can be seen in Ecuador, in which only 52.8% of rural households <br />have access to safe drinking water.</p>
<p style="text-align: justify;"><br />The problem of infected drinking water in rural communities begs the question: how does <br />one effectively eliminate the risk of microbial contamination without the use of electricity and <br />complex, expensive components? A solution: passive chlorination. Passive chlorination systems <br />use the flow of the water itself to release chlorine into the water. The chlorine then disinfects <br />the water, leaving it safe to drink.</p>
<p style="text-align: justify;"><br />The research that I conducted this summer, in conjunction with related research <br />conducted by a team of professors and engineering students, primarily involved assembling and <br />testing a chlorinator that was determined by literature review to be the most promising option <br />of several different passive chlorinators. The CTI-8, designed by Compatible Technology <br />International, is a low-cost chlorinator that can be made using hand tools and commercially <br />available PVC components. Using the provided instructions for building a CTI-8, I constructed and <br />tested one in a model system that was meant to mimic the flow conditions in Ecuadorian <br />communities. The model system was comprised of a hose-fed 50 gallon upper tank, a main pipe <br />line that split into two lines (one with the CTI-8 and one without it), a bypass valve, and a 50 <br />gallon lower tank into which both lines drained. This model system provided a way to run a series <br />of experiments to determine the dosing capabilities of the CTI-8, and to determine how to adjust <br />the bypass valve that controlled the ratio of water that went through the chlorinator versus the <br />ratio that bypassed the chlorinator.</p>
<p style="text-align: justify;"><br />The ability to control this ratio proved to be a very reliable means of controlling the final <br />combined concentration of the two lines. If more chlorine was needed in the lower tank, the <br />amount of water bypassing the chlorinator was reduced, and vice versa. Additionally, the CTI-8 <br />proved to be very effective at consistently dosing water for a wide range of flow rates. For this <br />reason, the CTI-8 will be implemented for an Ecuadorian community by July 2023. <br />Working with a team to develop and test a real-world solution has been eye-opening to <br />the multi-faceted nature of real-world engineering problems. In the case of Ecuador, access to <br />clean water is a societal, economic, and technological issue, making it a challenge to create an <br />appropriate solution that meets the needs of Ecuadorian communities.</p>