Passive Chlorination: Providing Clean Drinking Water to Ecuadorian Communities

Testing a chlorinator that was determined by literature review to be the most promising option of several different passive chlorinators.

In 2002, WHO reported that nearly 1.7 million deaths worldwide were caused by unclean
water. The risk of death by unclean water is elevated for young children, for which the second
cause of death worldwide is diarrheal disease, which is largely caused by microbes; these
microbes, when unaddressed, can proliferate in drinking water. Health risks are further elevated
in rural communities, which often lack access to the technology necessary to treat water for
microbial contamination. This can be seen in Ecuador, in which only 52.8% of rural households
have access to safe drinking water.

The problem of infected drinking water in rural communities begs the question: how does
one effectively eliminate the risk of microbial contamination without the use of electricity and
complex, expensive components? A solution: passive chlorination. Passive chlorination systems
use the flow of the water itself to release chlorine into the water. The chlorine then disinfects
the water, leaving it safe to drink.

The research that I conducted this summer, in conjunction with related research
conducted by a team of professors and engineering students, primarily involved assembling and
testing a chlorinator that was determined by literature review to be the most promising option
of several different passive chlorinators. The CTI-8, designed by Compatible Technology
International, is a low-cost chlorinator that can be made using hand tools and commercially
available PVC components. Using the provided instructions for building a CTI-8, I constructed and
tested one in a model system that was meant to mimic the flow conditions in Ecuadorian
communities. The model system was comprised of a hose-fed 50 gallon upper tank, a main pipe
line that split into two lines (one with the CTI-8 and one without it), a bypass valve, and a 50
gallon lower tank into which both lines drained. This model system provided a way to run a series
of experiments to determine the dosing capabilities of the CTI-8, and to determine how to adjust
the bypass valve that controlled the ratio of water that went through the chlorinator versus the
ratio that bypassed the chlorinator.

The ability to control this ratio proved to be a very reliable means of controlling the final
combined concentration of the two lines. If more chlorine was needed in the lower tank, the
amount of water bypassing the chlorinator was reduced, and vice versa. Additionally, the CTI-8
proved to be very effective at consistently dosing water for a wide range of flow rates. For this
reason, the CTI-8 will be implemented for an Ecuadorian community by July 2023.
Working with a team to develop and test a real-world solution has been eye-opening to
the multi-faceted nature of real-world engineering problems. In the case of Ecuador, access to
clean water is a societal, economic, and technological issue, making it a challenge to create an
appropriate solution that meets the needs of Ecuadorian communities.

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