Biosand-Filter

Biosand-Filter

Engineers Without Borders (EWB) is an international non-profit organization that focuses on using innovation and collaboration to help improve the quality of life for developing communities across the world. Here at EWB-BU, a student chapter of the national organization, we have partnered with a community in Naluja, Zambia to assist them in finding solutions to problems they face on a daily basis. Rather than simply providing the community with technology that may ease their life in the short-term, we are working with the members of the community to develop reliable and sustainable solutions to these obstacles and transfer our knowledge to them so that they will be able to fix any issues that may arise in the long-term.

One of the two projects that we are currently working on is a water-filtration system. Over the past several years, EWB-BU has sent groups of students to Zambia on two trips to assess the needs of the community. EWB-BU, the District Medical Officer of Zambia, and community elders have mutually agreed that access to safe-drinking water is a major obstacle that the community faces and which we can assist them in overcoming. Their water is highly contaminated by various forms of harmful coliform bacteria, leading diarrheal disease and other water-borne illnesses to be the primary health concern in the community.

After much research and analysis, we have decided that the bio-sand filtration device (BSF), which utilizes slow sand filtration, is their best option. Some of the reasons why we have decided to use this method are: its effectiveness in clearing up bacteria from the water, the availability of the necessary materials in the local area, low-maintenance, lack of interchangeable parts, spontaneity (driven by natural forces of gravity/water pressure rather than power), and its long lifetime. In the bio-sand filter, the water goes through a series of layers consisting of various sizes of sediment and a biofilm layer which forms naturally on the top to eliminate most of the organic materials and particles.

We are currently working on prototypes of the filter, which will be implemented in Naluja this coming summer during our next trip. We are looking into various design modifications on the filter to maximize the filtration of the water, as well as return water at an optimal flow rate. Some of the variations that we are experimenting with are changing the shape and size of the pipe, altering the size of each layer of sediments, and differing the design of diffuser plates. We have been carefully documenting our prototyping progress so that when our travel team goes to Naluja, Zambia this summer, the knowledge of how the bio-sand filter works and is constructed can be easily transferred. Our team members are very passionate about this project, cognizant of the impact it can have in a community consisting of ~15,000 people, and are hoping to finalize a design by the end of the semester to “Gear UP” for a successful implementation this summer.

For more information: Please contact ewbexec@bu.edu; visit us at http://people.bu.edu/ewbexec/ or join our group page on Facebook!


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Teamwork within the water-tech group of EWB, discussing prototyping modifications

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Our partners in Naluja, Zambia and 2013 travel team fixing a water pump in the village

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Sketch of the design for the Biosand-Filter (BSF), illustrating the flow of water through its layers

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Dimensions for the BSF design that will be implemented in Zambia this summer

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Preparing a PVC tube for the BSF

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Finished prototype of the BSF

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Preparing education/building manual to be used during the implementation of the project in Zambia this coming summer (August 2014).