Stephanie Litwack
Disclaimer—This paper partially fulfills a writing requirement for first year (freshman) engineering students at the University of Pittsburgh Swanson School of Engineering. This paper is a student, not a professional, paper. This paper is based on publicly available information and may not provide complete analyses of all relevant data. If this paper is used for any purpose other than these authors’ partial fulfillment of a writing requirement for first year (freshman) engineering students at the University of Pittsburgh Swanson School of Engineering, the user does so at his or her own risk.
BIOSAND FILTERS FOR CLEAN DRINKING WATER
Stephanie Litwack ()
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Stephanie Litwack
INTRODUCTION: THE CLEAN WATER CRISIS
For many families around the world, access to clean water is still a major issue. Not having safe water can have serious life impacts, so it is crucial that clean water is made easily available to people throughout the world. Biosand filters are one method of water treatment that can provide easy access to safe drinking water. Biosand filters are currently being utilized by The Engineers Without Borders (EWB) University of Pittsburgh (Pitt) Student Chapter is currently utilizing biosand filters as a method of water filtration in Brazil. Although they have their issues, biosand filters can provide a necessity of live: clean water. The filters are also still being researched in order to provide safer and cleaner water.
WHY CLEAN WATER MATTERS
For many Americans, clean water is a given. Clean water flows freely from most taps, showers, and water fountains throughout the country, which most people have access to. In some countries, however, there is no or limited access to water. Polluted water can cause all sorts of issues, including lack of education and illness.
In some communities, clean water can be retrieved from wells that are several miles away from homes. In these cases, the limited source of clean water often causes a lack in education. The children, often girls, of the family are sent to retrieve water during the day instead of going to school. Shail Khiyara discusses how this situation is present in African and Asian communities: “[I]n developing countries the burden of hauling water rests primarily on women and girls, and the average distance they carry their water… in Africa and Asia is 3.5 miles. Women spend several hours every day collecting water. This directly affects girls’ education and women’s ability to work and tend to their families” [1]. The time that these girls spend collecting water takes away from the time they spend on their education, which leads to many girls dropping out of school.
Perhaps the most important and most obvious reason clean water is so necessary is because of the illnesses polluted water can cause. According to the Centers for Disease Control and Prevention, polluted drinking water can lead to “gastrointestinal illness, reproductive problems, and neurological disorders” [2]. The severity of these issues helps to stress the importance of having access to clean water.
THE BIOSAND FILTER: A CONVENIENT SOLUTION
One solution to the clean water crisis is biosand filters. According to The Water Project, “The Biosand filter is comprised of a container - plastic or concrete - and is about the size of an office water cooler. It has an inset plastic pipe and is filled with layers of sand and gravel” [3]. Water is poured into the top of the container and filters through the sand and gravel, effectively cleaning the water [3]. The EWB Pitt Student Chapter states that as the water is filtered through the sand and gravel, “[c]ontaminants are removed from the water via several methods including mechanical trapping, predation in the biolayer, adsorption, and natural death” [4]. These multiple methods of removal mean that a large percentage of contaminants are removed and the water comes out clean and safe to drink.
Biosand filters are a convenient way to provide clean water to those in need. They are “specifically designed for household use” and “are built locally using available materials and labor” [3]. Although water still must be retrieved in order to obtain clean water, the biosand filter provides access to clean drinking water in the home.
BIOSAND FILTERS IN TAPAGEM
The Pitt Student Chapter of EWB is currently implementing biosand filters in a remote community of Brazil called Tapagem. Pitt’s EWB team plans to implement approximately 50 filters throughout the community in order to provide access to clean water [4]. These filters will provide a portion of the community with easy access to clean and safe water near their homes.
Since the filters are not 100% effective, EWB added an extra step in the process of cleaning the water. After the water is filtered, “[a]s an additional precaution, users will chlorinate the water prior to consumption” [4]. This added stop will ensure that the water is safe for drinking.
The Pitt EWB team is currently in the process of editing a manual that will instruct users in Tapagem to build their own filters. This manual will mean that the members of the community will be able to build the filters when EWB members are not present.
ISSUES AND IMPROVEMENTS
Although obtaining clean water from biosand filters is far better than having no filtration system, biosand filters have many flaws. One downside to biosand filters is that water still must be collected. Polluted water will be likely easier to retrieve than clean water, however, so the burden of collection water is not as large. Another flaw is that they do not remove 100% of the contaminants, hence the added chlorine for the EWB project. Also, since biosand filters are relatively small, they hold a limited amount of water.
Although the biosand filters are not currently 100% effective, some modifications for the filters are being added in order to increase the percentage of contaminants eliminated. A study was conducted at the University of Illinois where “[t]he addition of zerovalent iron to the sand media result[ed] in filters that more effectively remove[d] viruses from water” [5]. Another modification tested is a study conducted at the University of Michigan where they “developed and tested a vinegar-amended anaerobic biosand filter to treat groundwater containing arsenic, nitrate, sulfate, and iron” [6]. With continued research, biosand filters will be able to become more efficient at eliminating contaminants and viruses, thus making them more effective.
CONCLUSION: A TEMPORARY SOLUTION
Biosand filters are a good method for providing clean drinking water to the many people throughout the world that do not already have access to it. The usage of these filters can prevent issues such as illness and lack of education that no or limited access to clean water can cause. Through the implementation of biosand filters in Brazil, Pitt’s EWB team hopes to improve the quality of life for families in Tapagem.
Biosand filters are not perfect, and they are being researched in order to improve their effectiveness; however, these improvements do not account for other issues with the filters such as size. Biosand filters certainly provide a vital resource for those in need, but due to its flaws, it should not be considered a final solution. Because of their convenient size and fairly simple to make design, biosand filters are a good solution to temporarily provided access to clean water until better methods can be supplied.
SOURCES
[1] S. Khiyara. “Why is the global water crisis a women’s issue and the top global risk over the next decade?” The Huffington Post. 10.14.2016. Accessed 10.31.2016. http://www.huffingtonpost.com/shail-khiyara/why-the-global-water-cris_b_12450260.html
[2] “Water-related Diseases and Contaminants in Public Water Systems.” Centers for Disease Control and Prevention. 4.7.2014. Accessed 10.31.2016. http://www.cdc.gov/healthywater/drinking/public/water_diseases.html
[3] How Biosand Water Filtration Systems Work. The Water Project. 2015. Accessed 10.31.2016. http://thewaterproject.org/biosand_water_filtration
[4] “EWB Pitt Tapagem Project Design Report.” Engineering Without Borders USA. 2016. pp. 23-29
[5] I. Bradley, A. Straub, P. Maraccini, T. H. Nguyen. “Iron oxide amended biosand filters for virus removal.” Water Research. Vol. 45. no 15. 10.1.2011. pp. 4501-4510. Accessed 10.31.2016 http://www.sciencedirect.com/science/article/pii/S0043135411003198
[6] K. V. Snyder, T. M. Webster, G. Upadhyaya, K. F. Hayes, L. Raskin. “Vinegar-amended anaerobic biosand filter for the removal of arsenic and nitrate from groundwater.” Journal of Environmental Management. Vol. 171. 4.15.2016. pp. 21-28. Accessed 10.31.2016. http://www.sciencedirect.com/science/article/pii/S0301479716300421
ACKNOWLEDGMENTS
I would like to thank my friends Christina and Marissa for keeping me on track while writing this paper and helping me pick a topic to discuss. I would also like to thank the Pitt EWB team for giving me the knowledge necessary for writing about biosand filters.
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Stephanie Litwack
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