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dc.contributor.advisorSusan Murcott.en_US
dc.contributor.authorCollin, Clairen_US
dc.contributor.otherMassachusetts Institute of Technology. Dept. of Civil and Environmental Engineering.en_US
dc.date.accessioned2010-01-07T21:02:40Z
dc.date.available2010-01-07T21:02:40Z
dc.date.copyright2009en_US
dc.date.issued2009en_US
dc.identifier.urihttp://hdl.handle.net/1721.1/50623
dc.descriptionThesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2009.en_US
dc.descriptionIncludes bibliographical references (leaves 126-131).en_US
dc.description.abstractUnsafe drinking water is a major cause of water-related diseases that predominantly affect people living in developing countries. The most prevalent water-related disease is diarrhea, estimated to kill 1.8 million children every year and the second largest cause of childhood death. Today there are many technologies available to treat unsafe water; however, most of these are suited for use with low turbidity source water. The treatment of high turbidity water (>50 NTU) is a challenge that was investigated in this research. Biosand filters, based on an intermittent slow sand filtration process, are an established household scale water treatment technology widely used in developing countries to treat low turbidity drinking water. This research investigates modifications to the biosand filter design to promote effective pathogen and turbidity reduction in high turbidity water. During field tests conducted in Ghana, a modified biosand filter with dual sand layers for added filtration achieved the greatest pathogen and turbidity removals. This design was then optimised through laboratory studies at MIT. The dual sand layer biosand filter supports straining and sedimentation of particulate matter from the feed water in a 3-7 cm deep raised upper sand layer prior to biological treatment and further filtration of the water in a 15-16 cm deep lower sand layer. Field testing of the dual sand layer biosand filter showed this filter achieved 59% turbidity reduction, 38% higher than an unmodified control filter; and at least 85% E. coli and 95% total coliform reductions, comparable in performance to unmodified control filters.en_US
dc.description.abstract(cont.) Laboratory testing demonstrated minimum average reductions of 93% turbidity, 97% E. coli and 71% total coliform after filter maturation, comparable to unmodified control filter results. Dissolved oxygen concentration profiling in the laboratory indicated sufficient oxygen diffused through the upper sand layer to the lower sand layer to support biological activity in the lower sand layer. Recommendations for future studies and design optimisation have been made. Recontamination of treated water is also a major concern and it is recommended that the biosand filter be used only as required and filtrate collected in a dedicated container with tight fitting lid and tap dispenser.en_US
dc.description.statementofresponsibilityby Clair Collin.en_US
dc.format.extent154 leavesen_US
dc.language.isoengen_US
dc.publisherMassachusetts Institute of Technologyen_US
dc.rightsM.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.en_US
dc.rights.urihttp://dspace.mit.edu/handle/1721.1/7582en_US
dc.subjectCivil and Environmental Engineering.en_US
dc.titleBiosand filtration of high turbidity water : modified filter design and safe filtrate storageen_US
dc.typeThesisen_US
dc.description.degreeM.Eng.en_US
dc.contributor.departmentMassachusetts Institute of Technology. Dept. of Civil and Environmental Engineering.en_US
dc.identifier.oclc475694479en_US


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