Final Report: UV-Tube Design Concept for Sustainable, Point-of-Use Water Disinfection

EPA Grant Number: SU831825
Title: UV-Tube Design Concept for Sustainable, Point-of-Use Water Disinfection
Investigators: Nelson, Kara , Cohn, Alicia , Connelly, Lloyd G. , Kammen, Dan , Larsen, William
Institution: University of California - Berkeley , Rochester Institute of Technology , University of California - Davis
EPA Project Officer: Nolt-Helms, Cynthia
Phase: I
Project Period: September 30, 2004 through September 29, 2005
Project Amount: $10,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2004) RFA Text |  Recipients Lists
Research Category: Drinking Water , P3 Challenge Area - Water , Pollution Prevention/Sustainable Development , P3 Awards , Sustainability


1.1 Problem Definition

Waterborne Illness. The World Health Organization (WHO) estimates that waterborne illnesses associated with unsafe water, sanitation, and hygiene lead to the deaths of 1.7 million people annually and contribute heavily to the global burden of disease. In fact, waterborne illness is the third leading cause of morbidity and mortality in the developing world after underweight and unsafe sex (6). The burden of waterborne illness, a category that includes intestinal worms, typhoid, cholera, giardia, hepatitis A, and polio, falls disproportionately on children (16) leading to high under five mortality rates and aggravated malnutrition (5). Waterborne illness is also a significant economic burden to families. Parents are forced to take days off from work to care for their children and incur costs for medical treatment.

Safe Drinking Water. 1.1 billion people in the world still lack access to “improved” drinking water sources as defined by the WHO (16), but even “improved” sources are not necessarily safe to drink. In cities, central disinfection of piped water supplies is becoming more common; however, the systems often fail to provide adequate disinfection due to inconsistent dosing and deteriorated distribution networks. In rural and peri-urban areas without water networks, people often obtain their drinking water from contaminated springs, wells, rivers, or constructed ponds. In these situations, safe drinking water can only be obtained by treating water in the household at the point of use (POU). Unfortunately, none of the POU methods now available are panaceas for the waterborne illness problem in developing countries.

Water Treatment Methods. Providing centralized water treatment for the world is prohibitively expensive and, therefore, will not solve the problem of waterborne illness in the near future. There is an immediate need for “self-sustaining, decentralized approaches to making drinking water safe”(9). This need can possibly be met by POU water treatment methods.

In the industrialized world, when safe plumbed drinking water is not available, people either purchase bottled water or use commercial under-the-counter systems. Both methods are cost-prohibitive for most people in developing countries, though bottled water purchases from vendors are increasing. Pollution and energy use related to transportation of bottled water increase its environmental impact as does the proliferation of solid waste due to disposable plastic bags and bottles used in packaging it. Small commercial UV, ozone, or reverse osmosis (RO) water treatment units are effective and fast, but are typically priced above $300 US. These commercial units are also difficult to maintain and repair in developing countries because replacement parts must usually be imported and trained technicians are scarce.

Boiling and chlorine addition are probably the most common POU water treatments. Boiling is quite effective at eliminating pathogenic organisms. However, it is time consuming, produces only small volumes, and it is very energy intensive. In areas where wood or charcoal are used as fuel, extensive promotion of water boiling would aggravate deforestation and associated top soil erosion problems. Where wood is free but scarce, women and children already spend hours each day collecting it for cooking and are unable to collect more for boiling. Where fuel is expensive, boiling is cost prohibitive to poor families. In many areas that use wood or charcoal, cooking is done indoors on open fires and is a major source of indoor air pollution and associated acute respiratory infections (ART) (8). Chlorine addition is inexpensive, but requires an inconvenient contact time, is less effective at eliminating protozoa, helminthes, and some viruses than other methods, and is difficult to dose since the amount required depends on the water quality (9). Users complain that both boiling and chlorine addition lead to a negative change in the taste of the water.

Filters and solar disinfection techniques are promising. Current slow sand and silver impregnated pottery filters and SODIS and solar pasteurization kits re inexpensive and can be built from locally available or recycled materials (3). Unfortunately, POU filter and solar methods are slow and limited to small volumes. Solar techniques are weather dependent and do not work as well in cold climates. Also, slow sand filters are difficult to maintain safely leading to contaminated outlet water (3) and SODIS may not effectively inactivate viruses (12).

Need for sustainable solutions. The varied nature of drinking water problems necessitates diverse and complementary treatment techniques (9); there is a place for most of the techniques discussed above. However, there is still a huge need for sustainable technical solutions that protect the air, soil, and forests and are be economically feasible and appropriate to the community of users. Based on our research and experiences, we have documented the need for effective, simple, inexpensive, passive, fast, reliable method of water treatment that does not change the taste of the water. We believe that ultraviolet (UV) water disinfection technologies can be designed to meet users’ demands while protecting health and the environment.

1.2 The UV-Tube Design Concept

Multiple Design Options. The UV-Tube Project began in 1999 when the first UV-Tube was developed by a University of California at Berkeley (UCB) researcher working in Michoacán, Mexico. The project has since been handed down through three generations of UCB students. Many new designs have been developed, refined, and tested in the laboratory and field. Consequently, the UV-Tube has become a design concept, rather than a single design.

Similar to a number of water treatment plants in Europe and the United States, UV-Tubes use ultraviolet (UV-C) radiation emitted from a germicidal bulb to inactivate waterborne bacteria, viruses and protozoa. UV-Tubes, however, may be constructed from common, low- cost materials available in developing areas and are easy to use. Other small UV disinfection units on the market cost between $300 and $1000, a price much too high for POU use in developing countries. UV-Tubes, however, have been made by local people in Mexico for as little as $40. UV-Tubes meet users’ needs for effective, fast, and reliable water disinfection. They have less environmental impact than most methods of obtaining safe drinking water. Finally, UV-Tubes are a community-level solution to the problem of contaminated drinking water. They can be built and sold by local entrepreneurs or built and maintained by those wanting to sell treated water, and evaluated by users who provide feedback on the design.

To date, all UV-Tube designs incorporate a germicidal UV bulb suspended over water in a horizontal tube or covered trough. The water enters at one end through an inlet in the top of the tube, and then flows along the bottom (beneath the germicidal bulb,) until it reaches an outlet at the opposite end, where it exits. The height of the outlet sets the depth of the water in the tube and regulates the hydraulic retention time. Since the UV-Tube does n4t require water pressure to operate, it may be connected directly to a faucet or filled with a funnel and bucket. Different tube sizes and geometries are possible, because various germicidal bulb sizes are available. Student volunteers and community partners working on the project are encouraged to consider all materials that might be available in the field for making UV-Tues. Stainless-steel sheet, galvanized gutter, copper sheet, pottery, ferro cement, PVC pipe, and ABS pipe prototypes have been constructed. The most developed UV-Tube designs are the stainless steel-lined PVC (ss-PVC) tube design and a ferro-cement trough with cover (ferro-cement) design (see figure 1).

The UV-Tube as an Educational Tool. Recently the LFV-Tube has taken on an important pedagogical role in preparing students to confront global problems, consider the environmental, economic, and cultural sustainability of projects, work in interdisciplinary teams, and value public service. Using EPA P3 support, we offered a half-day UV-Tube “Brainstorm and Build” workshop in January 2005 where 18 participants learned about UV water disinfection and the issues for its implementation in developing countries, brainstormed new UV-Tube designs, and then worked in teams to construct a stainless-steel lined PVC (ss-PVC) UV-Tube. The workshop resulted in new enthusiasm, new design ideas, important improvements to the ssPVC UV-Tube construction manual, and two new team members. The new members started the “New Design Team” of the UV-Tube project. They are currently preparing prototypes for laboratory testing. We were also able to support a 2-credit, student+led course through the UC Berkeley DeCal (democratic education) program. The goal of the course, entitled “Engineer a Class: Create a Sustainability and Appropriate Design Course for UCB” is to design curriculum for a full-credit, service-learning class for the engineering school, potentially incorporating UVTube work as one of the class projects. This year the UV-Tube project has become an official project of the Engineers for a Sustainable World—Berkeley (ESW-B) student organization, providing us with many opportunities to present our work for peer evaluation as well as to recruit new volunteers. In fact, a team of ESW-B members working on water issues in Baja California Sur wrote a proposal and received funding from the United Nations Industrial Development Organization — Management of Technology International Research Fellowship (UNIDO-MOT Fellowship) to field test the UV-Tube in Baja California Sur, Mexico during summer 2005. Another group of ESW-B students received funding from the Chancellor of UC Berkeley to bring the UV-Tube concept to Sri Lanka in an effort to address water quality issues in tsunami- affected areas. Beginning next fall, a UV-Tube design project will be incorporated into the environmental engineering module of a new, required freshman seminar course called Engineering Design and Analysis. Finally, we were invited to present the UV-Tube at a number of local events this year, including: the Center for Information Technology Research in the Interest of Society (CITRIS) groundbreaking at UC Berkeley, the Engineers for a Sustainable World—Berkeley Concert Fundraiser, the CalSci teaching program for high school students, the Social Entrepreneurial Gala held by the Haas School of Business at UC Berkeley, the Oakland Girl Scouts’ “Girls Go Tech” event, the Appropriate Engineering Technology in Developing Communities (Drinking Water Quality for Health) class at UC Davis, and the Environmental Physical-Chemical Processes class at UC Berkeley. An article is in press for Society of Women Engineers SWE Magazine, and a radio piece will appear on the National Science Foundation’s “Imagine That!” program. We also use the UV-Tube as an educational tool for promoting the prevention of waterborne illness with our community partners in Mexico and Haiti.

1.3 The Experience of Our Community Partners

Field Sites. At the time of writing Phase I of this proposal, we had two fields sites: Cuernavaca, Mexico, and Borgne, Haiti. We have since added a new field site in Baja California Sur, Mexico and we are exploring the potential for using UV-Tubes in, Sri Lanka.

H.O.P.E., Borgne, Haiti. Haiti is not only the poorest nation in the western hemisphere, but it also ranks last on the Water Quality Index, a rating system incorporating water supply, drinking water quality, water use and management, and the health of natural water bodies (2). Only 45% of rural Haitians have access to WHO defined “improved” drinking water sources (15). Haiti also has the third highest deforestation rate in the world (13), and cooking on indoor charcoal stoves aggravates the problem. Our community partner is Haiti Outreach: Pwoje Espwa (H.O.P.E.), based in Rochester, NY and Borgne, Haiti. Since 1995, H.O.P.E. has initiated projects with local partners in the community-defined priority areas of health, education, and economic development. Diagnostic data from the H.O.P.E. Health Clinic indicate, that at least a quarter of all patients come suffering from preventable waterborne illnesses. H.O.P.E.’s Sant Teknoloji Bwase Lide, a “Brainstorming Technology Center,” applies a systems approach incorporating health education, water treatment, safe water storage, and sanitation to the problem of waterborne illness—an approach that is likely to have longer lasting positive impacts on public health than other types of interventions (9). A ferro cement UV-Tube is currently installed at the Sant Teknoloji and visitors treat 30 to 50 gallons of water/day, twice a week. Further UV-Tube installations in Borgne are temporarily on hold until H.O.P.E. can address water supply problems caused by a deteriorating distribution system and lack of governmental support for infrastructure. Also, our partner, Engineers for a Sustainable World, will not support student travel to Haiti until the U.S. State Department Travel Advisory is lifted. In the mean time, UCB students will continue to improve the ferro cement UV-Tube design for future use in Borgne.

Waterborne illness in Mexico. In Mexico the waterborne illness situation is less grave, but many people still lack access to safe drinking water. Over the last few yeas, the Mexican government has been promoting research on and implementation o household-scale drinking water treatment systems. UV disinfections is a promising household technology because many people have both electricity and piped water (although not safe to dink) in their homes. Our partner organizations are the Mexican Institute of Water Technology (Instituto Mexicano de Tecnologia del Agua, IMTA) and the National Council for the Promotion of Education (Consejo Nacional de Fomento Educativo, CONAFE), which are both part of the federal government.

IMTA. The Instituto Mexicano de TecnologIa del Agua’s (IMTA) mission is to research, develop, and disseminate water technologies. They have done extensive work to promote SODIS (solar disinfection using plastic bottles and sunlight) in rural areas including research to optimize the SODIS procedure and the production of educational brochures and videos on the technique. In January 2003, the UV-Tube project team presented the first UV-Tube design to IMTA investigators as an inexpensive household water treatment option. IMTA then validated the UV-Tube according to Norma 180, the Mexican standard for household drinking water treatment units and graduate students at IMTA improved the UV-Tube design.

CONAFE. The Consejo Nacional de Fomento Educativo (DONAFE) is charged with providing elementary education for small rural communities in Mexico. In the state of Baja California Sur, CONAFE has a cadre of 15 Supervisors and 150 Community Educators who are responsible for the pre-primary and primary education of 1,200 students in 150 communities. Apart from fulfilling its educational goals, CONAFE has also assisted with community- development programs (such as photovoltaic rural electrification) by serving as the communities’ voice and by introducing educational kits that promote sustainable paths. CONAFE reports that most of the communities where it operates schools do not have access to a potable water supply and waterborne illness is one of the leading causes of instructors’ and children’s absenteeism. The ESW-B “Agua SALud” project team worked with CONAFE during summer 2004 to test drinking water sources in the communities of Baja California Sur. Their water testing results confirmed that more than half of the population drinks water containing fecal contamination and 10.7% of children surveyed had suffered from diarrhea in the previous week (14). Members of the Agua SALud team recently received funding from the UNIDO-MOT Fellowship to field test 30 UV-Tubes in Baja California Sur in 2005-6.

Sarvodaya, Sri Lanka. Following the tragic tsunami, Sarvodaya, a Sri Lankan NGO working in water and sanitation contacted the UV-Tube project through a UCB student who was volunteering in the emergency relief effort. Sarvodaya requested information on identifying post tsunami water quality issues, water testing, and the UV-Tube and other water purification methods for treating salinity and bacterial contamination. The UC Berkeley Office of the Chancellor Funding has provided funding for student to travel to Sri Lanka to assess the situation and offer water testing and UV-Tube training workshops in August 2005.

Summary/Accomplishments (Outputs/Outcomes):

The overall purpose of the UV-Tube project is to make UV water disinfection available to those who need it most. Phase I P3 funding was sought to validate UV-Tube designs in the laboratory and the field, to recruit new, diverse members to the UV-Tube team, and to use the UV-Tube project to foster discussion of sustainable design concepts on campus. The objectives outlined for Phase I were defined as follows. (In the original proposal, additional long term objectives and goals for work in Haiti considered to be outside the scope of the P3 award were included in italics to show overall project direction. These objectives are not discussed here.)

Phase I Objectives (solid dots indicate objectives that we feel we have successfully achieved or are nearly complete, arrows indicate objectives which are in process, and open dots indicate areas that need more work)

University of California at Berkeley Research

  • Validating the ss-PVC UV-Tube design in the laboratory.
  • Conducting bulb studies to recommend warm up time and bulb replacement schedule.
  • Leveraging the UV-Tube project as a pedagogical tool to incorporate sustainable design concepts into the UC Berkeley curriculum.
  • Increasing the number of professors including sustainable design curriculum in courses.
  • Encouraging student teams to improve the ferro-cement UV-Tube design and develop two new designs.
  • Validating the ferro cement and two new designs in the laboratory.

IMTA, Cuernavaca, Mexico field study of the ss-PVC U V-Tube

  • Conducting a workshop where users build UV-Tubes.
  • Field testing the ss-PVC UV-Tube in 5-10 households.
  • Demonstrating technical robustness of the UV-Tube in households.
  • Assessing demand and user preferences for/against using the UV-Tube.
  • Assessing user perceptions of health after using the UV-Tube.


During the first seven months of Phase I, we have already achieved quite a few of our objectives as well as some unexpected successes.

Germicidal Effectiveness. One of our main objectives was to quantify the germicidal
effectiveness of the ss-PVC prototype. To do this, we developed a laboratory procedure based on NSF/ANSI 55-2002, the NSF International Standard! American National Standard for drinking water treatment units—Ultraviolet microbiological water treatment systems (10). MS2 bacteriophage, a UV resistant virus that infects E. coil, was used to establish the average fluence (dose) of UV light transmitted to water passing through the prototype at a specified flow rate.

We conducted a series of eight MS2 coliphage tests on the ss-PVC prototype; four of the tests gave conclusive results. We discovered that bringing in new student volunteers to help with the test almost always resulted, in contaminated samples and inconclusive test results. Although it is our intent that the UV-Tube be installed so that it is level from inlet to outlet, we also conducted a fifth, “worst-case scenario” test with the UV-Tube installed tilted at 4° (the inlet 4.5 cm higher than the outlet). Because tipping the UV-Tube reduces the hydraulic residence time the UV-Tube from 36 seconds to 21 seconds, we expected the UV dose to be reduced. The log-inactivation results of the four tests of the level UV-Tube and the “tipped” test are shown with 95% confidence intervals in figure 2. Our fluence-inactivation curve is shown in figure 3 and consistent with results of other researchers compiled by Batch et al. (1). The dashed lines designate the upper and lower MS2 inactivation guidelines as defined by the NWRI AWWARF (11). Because our inactivation curve is on the high side of the guidelines, we plan collect more fluence response data to ensure that it is accurate. At a flow rate of 5 L/min the average log reduction of MS2 in the four UV-Tube challenge tests was 4.33, translating into an average fluence of 927 J/m2, more than double the NSF/ANSI recommended fluence of 400 J/m2 (10). Although variability between samples and tests is evident, the doses are sufficiently high to ensure consistent pathogen inactivation. Even when tipped, the UV-Tube provides a fluence of 745 J/m2.

Because the MS2 test is very labor intensive, and we had to repeat the ss-PVC testing, we have not yet tested other designs. Testing of new designs is scheduled for late April 2005.

Tracer Studies. Tracer studies help to characterize the flow dynamics of a reactor and reveal potential problems. Results of tracer studies on the ss-PVC UV-Tube at 5 L/min indicate that the residence time of the water in the UV-Tube is 31.4 seconds, quite similar to the theoretical residence time (flowrate/volume of 33.2 seconds. The E(t) curve shows the fraction of dye exiting as a function of time (figure 4).

Some distribution of residence times is evident, but based on our MS2 results, we feel confident that even water spending the shortest time in the UV-Tube receives sufficient dose of UV We have not detected dye exiting the UV-Tube before 12 seconds, indicating that short circuiting (water passing quickly and not getting sufficient UV dose) is not a problem. We are continuing to revise our tracer study procedures in order to increase the percentage of dye recovered during a test.

Materials Degradation. To ensure that UV-Tubes do not produce harmful disinfection by-products, we conducted tests to simulate possible household operating conditions. The inlet and outlet water samples are sent to a laboratory for analysis for metals and common volatile organic compounds (VOCs). Materials stability tests of the stainless ss-PVC UV-Tube have given mixed results. Even with the stainless steel lining, during extended UV exposure of stagnant water, some by-products are produced at detectable levels (most likely due to the UV exposed PVC end caps). The levels, however, are well below levels that would lead to a person to consume a daily dose above the US Environmental Protection Agency’s reference daily oral dose. Since PVC ‘is readily available, inexpensive, and easy to work with, it may be the only viable option in some areas. Also, the health risk associated with the by-products is small compare to the health risk of waterborne illness.

Bulb Studies. Although information on the bulb studies was not presented in the Phase I proposal (because the supplies had already been purchased) the results are very relevant to P3 goals. Manufacturers recommend that UV bulbs warm up for 10 minutes before use and that they remain on continually to ensure provision of their rated UV output for 1 year. However, these conditions are not ideal for UV-Tubes operated where electricity is intermittent, expensive, or provided by solar or battery power. Also, turning the ss-PVC UV-Tube off between uses reduces the risk of PVC by-product formation. Because little information is available from the manufacturer on bulb UV output and lifetime under non-ideal operating conditions, we conducted bulb studies to determine bulb characteristics. Our results suggest that users can increase the useable lifespan of the bulb before replacement up to 5-6 years if the bulb is turned on only once a day for 1 hour. A bulb warm-up time of 5 minutes is necessary to reach full UV output, but bulbs reach more than 90% of their maximum output after being on for 2 minutes.

Field testing with IMTA. Because of bureaucratic delays at the UCB due to approval of the human subject proposal and heavy workloads for researchers at LMTA, we were unable to start the full field study as planned in January 2005. Instead, 10 families will build their own UV-Tubes during community workshops held in May 2005, followed by installation of UVTubes in their homes for the year long study proposed in Phase I. Nevertheless, IMTA was able to conduct a preliminary study in three homes in the municipalities of Jiutepec and Yautepec, near IMTA offices in Cuernavaca, Mexico. Users did not build their own UV-Tubes, but used them for drinking water treatment purposes within their homes. Two of the UV-Tubes have been installed since September 2004; one was removed for repairs. The first of the installed prototypes is used twice a week by the family and has been tested periodically by IMTA; the other is used once every two weeks, but irregularity in the water supply hindered testing.

IMTA’s experience with this study and the results of the user surveys suggest that the area near Cuernavaca is not the appropriate niche for the UV-Tube. The water supply is very intermittent. Sometimes tapped water is only available once every two weeks which makes scheduling times for researchers to view the UV-Tube in operation and test the outlet water difficult. Bottled water is heavily advertised in the area, is relatively inexpensive, and is promoted by health agencies. Also, there is a Coca Cola water bott4ng plant on the main road near the communities. IMTA recommends field testing the UV-Tub in areas away from urban centers where bottled water is less ubiquitous and water supplies are considered more contaminated. On the technological side, the UV-Tube functioned well, despite inadequate maintenance. Outlet water test results were negative for E. coil and total coliforms—indicators of contamination. However, IMTA researchers also tested UV treated water that had been stored in the household. They found recontamination of the stored water, and they attributed it to users collecting treated water in dirty containers or dipping into the treated water with dirty dippers. IMTA suggests that these operating problems can be avoided with more thorough follow up and reinforcement of operating procedures with users, and they have requested resources to improve follow up and testing during the full field study (see Phase II proposal). When asked for input on improving the design, users suggested decreasing the size and improving the aesthetics.

In contrast to Cuernavaca where IMTA found it difficult to find field study participants, UC Berkeley students visiting rural communities in Baja California Sur reported high levels of interest, from community members in having a UV-Tube. Hardware stores in La Paz also agreed to assemble materials or build UV-Tubes for the Baja field study this summer.

New Designs. Several innovations to the UV-tube design have been gaining momentum this spring. One exciting approach folds the stainless sheet to contain the water without a PVC pipe and without seals. This avoids unwanted leaks, yet ensures that uncontrolled inlet water flow would spill rather than drown the UV bulb. These and related designs promise to improve performance, longevity, and aesthetics while eliminating risk of contamination from UV-exposed plastics. Also, we are investigating ways to make the UV-Tube more energy efficient while generating less solid waste. UV LEDs would be an energy efficient and safer (no mercury) replacement for the mercury vapor UV bulbs we are currently using. Therefore, we are pushing for development of UV LEDs that can be used for the public good (i.e. they are not patented for use in water disinfection.)

Dissemination, Education and Outreach. Efforts to employ the UV-Tube as an educational tool were very successful and are described above in section 1.2, The UV-Tube as an educational tool. Our student survey results suggest that, currently, sustainability issues are poorly covered in UCB classes. We will conduct a follow up survey next year to quantify changes. We also have a UV-Tube website at We will continue to add new information including construction and operation manuals to the website. Dissemination of the UV-Tube will be our main focus for Phase II.

I. People, prosperity, planet. We desire to make the UV-Tube an economically, culturally, and environmentally sustainable technology for use in 4eveloping countries. As evidenced by our project’s variety of tests and activities, we have attempted to consider people, prosperity, and the planet. We are concerned with reduction of waterborne illness, safeguarding the health and productivity of communities, UV-Tube affordability, aesthetics, and ease of use, opportunities for users to save money using UV-Tubes to meet water needs, opportunities for businesses to sell UV-Tubes or treated water, low operating and maintenance costs, reduced energy use over other methods, reduced consumption of resources such as wood or fossil fuels, and finally, working toward making UV-Tubes out of more environmentally sensitive materials.

II. Successes & Challenges. Although some of our work is still in progress, we are extremely satisfied with our successes to date. Based on 1aboraory testing, we now feel confident that the ss-PVC UV-Tube will provide consistently safe drinking water at 5 L/min, even if it is installed incorrectly. Preliminary results from field installations provided useful information on user preferences and potential niches for the UV-Tube. For example, for city dwellers the UV-Tube must be smaller, more attractive, and easier to use; however, the current design seems acceptable in rural areas. At UCB, we have fostered the process of student-led curriculum development for a sustainability and appropriate technology class that will become a technical elective for engineering students next year. We have also encouraged student groups and professors to discuss these topics with their classes and groups. Recruiting a variety of new dedicated members, sharing our work for comment/criticism, and bringing new ideas and energy from many people have been the most important steps we have taken toward achieving success.

Apart from the challenges described previously, our main challenges were lack of time and difficulties negotiating university bureaucracy. If we were to rewrite this proposal from the beginning, we would modify our timeline. We overestimated the amount of work that can be done with volunteer student labor both at Berkeley and at IMTA in 1exico. We are currently seeking funding elsewhere to support a graduate student researcher for the UV-Tube project. Another major problem was the loss of our Human Subjects paperwork (by the campus committee) partway through the renewal process, which held up the release of our funding from the Sponsored Projects Office. Although our Phase I plan was ambitious for a one-year time frame, the plan still serves as the overall vision for IJV-Tube project work. As we move into Phase II with new volunteers, we feel that we will be able to complete the Phase I work and begin efforts for wider dissemination of the UV-Tube.

III. Team Member Contributions. Three of the team members involved in Phase I were environmental engineering students and were responsible for developing and carrying out the laboratory validations. Because of the progression of the project toward the dissemination stage, we have recruited new team members: a physics student is creating new designs, business students are developing dissemination ideas, willingness to pay surveys, and market studies, and Energy Resources Group students are investigating the overall sustainability of our project, including cultural acceptability, life cycle analysis, and energy use assessments.

IV. Fostering the Movement Toward Sustainability. UV-Tube designs are less expensive and more energy efficient than most water treatment methods, and we continually encouraged new design team members to use more environmentally friendly materials in their designs. However, our teams’ most important contribution to sustainability is probably the push for inclusion of more sustainability and appropriate design curriculum in the UC Berkeley School of Engineering. Changes are underway and the UV-Tube project team members have been major players in making this happen, thanks to the P3 inspiration and funding.

V. Applicability. The UV-Tube is designed to be adapted to local needs in material, design, and use. The goal of the project is to develop a number of designs that can be used in various contexts. It may not be appropriate for areas without electricity, but could be used as a community system with solar, battery, or generator power.

VI. External partners. Our partners include the ESW-B student group, IMTA and CONAFE in Mexico, H.O.P.E. in Haiti, and Sarvodaya in Sri Lanka. We have also received $18,651 from the UNIDO-MOT fellowship, $19,728 from the Chancellor of UCB and $1,500 from the Latin American Studies Department at UCB. This funding was not included as matching funds for Phase II because it will be used this summer (before September 2005).

VII. Quantifiable Impact. Fewtrell et aI.’s meta analysis (7) indicates that point-of-use water treatment interventions can reduce the incidence of waterborne illness by 39% (95% CI: 11-47%). Although we did not collect incidence data for the families who were part of the field study, based on waterborne illness prevalence rates for all of Mexico of 6%, we estimate that the 30 participants collectively suffered 36 fewer incidents of waterborne illness this year because of using the UV-Tube. In Phase II we will move into dissemination of UV-Tubes in Baja California Sur. Last summer, Aqua SALud recorded a waterborne illness prevalence rate of 10.9% for children in rural communities served by CONAFE in Baja California Sur. If the 59% of CONAFE school children who are currently drinking untreated water (~700 children) instead drank from UV-Tubes, they would suffer -1 560 fewer illnesses annually (14). (Assumptions for converting prevalence to incidence: an illness duration of less than 1 week; a new illness does not occur in the same week.) Fewer illnesses translate directly into money saved on health care as well as improved school performance and overall nutrition (4).

From our bulb studies we are able to recommend new operating procedures that improve safety (fewer PVC by-products), reduce costs, and are energy-efficient. As compared with the bulb manufacturer’s recommended 24-hour/day operation, turning the UV-Tube on for one hour a day to treat water reduces a family’s cost of bulb replacement by up to $8/year and their energy costs by $15.12/year (electricity cost of $0.12/kW-hr), and saves 126 kW-hr/yr of energy. Cost and energy comparisons are shown for the UV-Tube and other water treatment methods in figure 5 (assumptions are attached as Appendix A). UV-Tubes are more energy and cost effective when more people use them. Other qualitative advantages of the UV-Tube for users include no added taste or odor to the water, not having to carry or take time to transport water, and an increased sense of self-reliance and control over meeting family water needs.

VIII. Innovation or Adaptation. The UV-Tube project seeks innovated approaches to using existing knowledge. Our goal is to adapt the idea of UV water disinfection for use in developing countries. Many of the 1.7 million deaths each year from waterborne illnesses are preventable. The UV-Tube is another technology to add to the toolbox of methods for preventing them. Laboratory and preliminary field testing suggests that the UV-Tube is technically able to provide safe drinking water. The main question remaining lies tin how to safely and quickly build and disseminate quality UV-Tubes to the millions of people who may want to use them.

Supplemental Keywords:

RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Water, Environmental Chemistry, Ecological Risk Assessment, Drinking Water, Environmental Engineering, alternative disinfection methods, Safe Drinking Water, disinfection of waters, UV treatment, treatment, drinking water distribution system, microbial risk management, point of use, water disinfection, water treatment, drinking water treatment, contaminant removal, other - risk management, ultraviolet disinfection

Relevant Websites:

Phase 2 Abstract
Phase 2 Final Report

P3 Phase II:

UV-Tube Design Concept for Sustainable, Point-of-Use Water Disinfection  | Final Report