The thirst of a thousand

Jessica Jackson
Intern, Pountney Consulting Group, Inc.
San Diego, California

In Deboshea, Haiti, a community of about one thousand people, funerals are common—approximately every twenty days another life ends. Often it is the life of a child. Aaron Green, former well driller for Hospital Albert Schweitzer, relates that eighty-five percent of these deaths are caused by contaminated water. Clean water would profoundly change the lives of the people of Deboshea. So, Jessica Jackson, an environmental engineering student at San Diego State University and an intern at Pountney Consulting Group, and Dr. Greg Loraine of the Department of Civil and Environmental Engineering at S.D.S.U., designed a water treatment plant for this peasant village, conscious that it needed to be functional, robust, low-maintenance, and low-cost to the peasants.

In order for the design to be functional in Deboshea, it could have no reliance on electricity and should have few mechanical parts. This was accomplished by a combination of long-standing methods and modern technology. In imitation of nature, the water moves through the system due to gravity as sedimentation works to eliminate particulate matter along with a slow sand filter, which also eliminates up to ninety-nine percent of Giardia cysts and coliform bacteria in the water. A solar-powered hypochlorite generator coupled with a non-electric proportioning pump account for the innovations. The generator converts salt into hypochlorite bleach for disinfection. The proportioning pump adds the correct dosage of bleach to the water as it flows through the system to ensure disinfection. This combination of old and new results in a simple and effective treatment process.

Robustness was weaved into the design to create an enduring plant. The structures, constructed of concrete, are inherently durable for many decades. The hypochlorite generator and proportioning pump have minimum lifetimes of fifteen years. Should the generator or pump fail, minimal treatment can still be attained by the slow sand filters.

During this time, minimum simple maintenance will be required. The sedimentation tanks will need to be drained and cleaned out in regular intervals (for which a valve is provided). The slow sand filters are built in parallel so periodic maintenance will not disrupt water production. The slow sand filters are maintained by scraping off the top layer of sand and allowing the filter to condition for twenty-four hours. The hypochlorite generator requires salt and will need to have the electrodes soaked in vinegar weekly. Lastly, the effluent will need to be tested each day using paper test-strips to assure that the chlorine levels are safe.

In order to maintain the system, there will be some cost to the peasants, but it will be minimal, as most of the expense lies in the initial cost. The estimated cost for the needed salt, vinegar, and test-strips is less than one hundred dollars a year.

Through this functional and robust water treatment plant with minimum required care, up to 3,500 g.p.d. of water will be provided to sustain the people of Deboshea, Haiti. The design is presently complete and Ms. Jackson is in Haiti participating in the overseeing and construction of the plant.

After Jessica Jackson returns to San Diego from Deboshea, she can be reached at (858) 576-9200.