Back to Summer 2009 Newsletter
Eight University of Arizona engineering students, members of the UA chapter of Engineers Without Borders, traveled from their Tucson campus to villages in Ghana West Africa to assist villagers obtain a safe, secure drinking water source. The socially conscious students’ good hydrological deed reflects the ideals of the EWB, an internationally recognized humanitarian organization with professional and student chapters.
The project that eventually involved the UA EWB chapter had its beginnings in 1995 when approximately 30 communities with a combined population of 10,000 in the Mafi Zongo area of Ghana’s Volta Region wanted to improve water quality and accessibility to combat the endemic and debilitating Guinea Worm parasite. A grass-roots effort was organized and the Ananda Marga Universal Relief Team, a locally active non governmental organization, was approached for support.
Work progressed; by early 2002, the dam was completed and the reservoir was filled to capacity during the region’s major rainy season occurring in May and June. A treatment facility was then constructed utilizing source water pretreatment followed by slow sand filtration.
The community owned and operated system, however, soon experienced operational difficulties. The primary concern was that the slow filtration rate through the treatment plant resulted in irregular water deliveries.
This then was the prologue to the EWB-UA involvement in the project as AMURT and the communities turned to EWB for technical assistance.
The UA team’s first two trips, in January and August 2006, were to delineate the watershed and determine reservoir capacity. The primary purpose of the visits, however, was to determine the cause of slow filtration rates that was hampering efforts to distribute clean water on a regular basis. After evaluating both the treatment plant and source water quality, the team determined that slow filtration rates were caused by inadequate pretreatment of the source water resulting in the clogging of the slow sand filter.
In response, EWB UA designed an improved pretreatment system to prevent clogging of the slow sand filter. During the two most recent trips, in February and March 2009, the team oversaw the construction of a gravel pretreatment system.
The February and March 2009 visits were devoted to laying the foundation and formwork/pouring for the filter’s concrete exterior and interior walls. The community then took over to sort and wash gravel needed for the filter media. The teams’ visit in May was to install plumbing and start up the filter.
An enormous amount of labor was required to hand sieve the gravel into the different size classes and then hand wash it before placing it in the filter. As a result, only half of the required media was ready for placement during the team’s May visit. Since the filter was designed to split the flow into two treatment trains, the team was able to start up one of the trains with the gravel ready for placement. The villagers participated in the process and are now completing the start up process on the remaining portion of the filter.
By the end of the team’s last trip, the village was using the new filter to produce about 60 cubic meters of water per day. The difference between that amount and the demand of approximately 90 cubic meters per day is being met with the old gravel filter. The new filter, however, has been working as designed and improving the raw water to a turbidity level acceptable for subsequent treatment by slow sand filtration.
Participating in the on-site project were six professionals and eight students. Professionals include: Ty Morton (CH2M Hill), Scott Beeson (CH2M Hill), Treye Konrath (Grenier), Sowmya Somnath (Grenier), Wendell Ela (UA Professor) and Jeff Michaels (Hunter Contracting). The UA students are: Samantha Treese, Amanda Plourde, John McElligott, Bethy McGehee, Dave Newman, Dane Whitmer, Terra Michaels and William Casson.
As this project nears completion EWB UA has begun work on a new project in Mali, also in West Africa, in the Sahel, one of most arid regions of the world. The project is to increase potable watersupplies to villagers through community scale water harvesting. In May, the team made an assessment trip and is currently evaluating design alternatives and is engaged in fundraising. Watershed Management Group, an organization that has been active in water harvesting activities in Southern Arizona, is providing technical expertise, as well as the UA Soil, Water and Environmental Science Department. Errol L. Montgomery & Associates, which has experience with potable water projects around the world, also is providing expertise.