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

EPA Grant Number: SU832462
Title: UV-Tube Design Concept for Sustainable, Point-of-Use Water Disinfection
Investigators: Nelson, Kara , Kammen, Dan
Institution: University of California - Berkeley
EPA Project Officer: Page, Angela
Phase: II
Project Period: September 30, 2005 through May 30, 2006
Project Amount: $75,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2005) Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Water , P3 Awards , Sustainability


The UV Tube was developed at the University of California, Berkeley as a method to disinfect water at the household level. The UV Tube utilizes a low watt lamp, similar to a common fluorescent tube, which emits light at a wavelength optimal to disrupt the nucleic acids, and therefore the viability, of waterborne pathogens. A main advantage of the UV Tube over other point‐of‐use water treatment options is its ability to inactivate waterborne viruses, bacteria, and protozoa; chlorine is not considered fully effective against protozoa and filters are not always effective against viruses. Furthermore, users have perceived the UV Tube as a highly attractive technology both due to its aesthetic appeal and its capacity to disinfect water at a fast rate (5 liter per minute) without affecting its taste or temperature. Through its unique combination of efficiency, effectiveness and attractiveness the UV Tube has great potential to be implemented as part of a sustainable safe water solution.
We desire to make the UV Tube an economically, culturally, and environmentally sustainable technology for use in developing 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.
Proposed Phase II Objectives and Strategies:
During the EPA P3 Phase I, we learned how to validate UV Tube designs in the laboratory, worked with partner organizations to pilot test the UV Tube concept in the field, and we used our UV Tube experiences to foster a sustainable design discussion on campus.
In Phase II we proposed to expand the use of the UV Tube as an educational tool, both to influence the sustainability curriculum on campus and to recruit more students to become actively involved in the project. With a larger and more diverse team, we planned to develop new designs and better prototypes, to research pre‐filtration options for the UV Tube, to increase our capacity to validate UV Tubes in the lab, and to build stronger relations with partner organizations. Together with our partners, we sought to install more UV Tubes in the field and to obtain user feedback with the goal of improving our technology and implementation strategy. Although all these objectives are greatly interconnected, we structured them in the following way:
Utilize the UV Tube as an Educational Tool in workshops, classes, and public presentations in order to bring attention to the importance of sustainable design and to encourage more student participation in UV Tube project.
Advance the UV Tube’s technological development process by improving laboratory validation techniques, developing new UV Tube designs, and identifying pre‐filters that adequately match the UV Tube characteristics.
Expand the UV Tube’s impact by strengthening partnerships with the Mexican Water Technology Institute (IMTA) and Fundacion Cantaro Azul.
Evaluate the performance of the UV Tube in the field and obtain feedback from users and collaborators to improve the technology and its promotion strategy.

Summary/Accomplishments (Outputs/Outcomes):

Utilize the UV Tube as an Educational Tool
In the Fall 2005, the UV Tube was used as one of the four case studies presented to in the required freshmen seminar “Engineering Design and Analysis”. Also in the Fall 2005 semester, Sarah Brownell from the P3 UV Tube team organized and led a DeCal class that developed the curriculum for a Design for Sustainable Communities class that became a full credit class taught annually by Prof. Ashok Gadgil. The class is unique in its content and its focus on hands on projects. In the Spring 2006 semester, Fermin Reygadas (P3 UV Tube team member) served as Graduate Student Instructor for the class and led the UV Tube class project, in which four students work throughout the semester to understand the fundamentals of the UV Tube and to contribute to new UV Tube designs. One of the developed prototypes was installed by the students in two households in the Central Valley in California. Also, three of the students applied their newly learned skills during the summer, as they worked for one month in Baja California Sur, Mexico with the P3 UV Tube team members adapting their design to the local needs. The UV Tube served as a great educational project as it was able to provide students with hands‐on work in the lab and the field, as well as allowing them gain real life experience during their internship in Mexico.
Advance the UV Tube’s technological development process
During the Phase II of the EPA P3 grant period, we worked at UC Berkeley on the development of new UV Tube designs that are safer, easier to use, and more aesthetically appealing. We improved the AquatUVo version, which consists of a sheet of stainless steel rolled around 3” PVC generic end‐caps. The AquatUVo proved to provide a high enough UV dose (800 J/m2) and passed the degradation tests. Although the end‐caps used in the AquatUVo can be easily found in any hardware store, the required adaptations that serve as inlet and outlet pipes proved to be a limitation of the design, especially for projects that seek to install more than 20 UV Tubes. Such adaptations are time consuming and lead to quality control problems. For this reason the P3 UV Tube team and Fundacion Cantaro Azul decided to design plastic injection molds for the end‐caps. A draw‐back of the plastic injected end‐caps is the creation of a dependency on a particular piece, as opposed to the widely available 3” PVC end‐caps. However the team decided that the advantages in improved product quality, higher production capacity, lower costs, and long lasting characteristic of the plastic injected end‐caps could outweigh the dependency disadvantage for large scale projects. The UV Tube made with the new end‐caps was tested in the lab resulting in a UV dose of 1,100 J/m2. The higher dose corresponded to a slight increase in the diameter of the end‐cap, which augmented the volume of the tube and thus the average period of time that water was exposed to the UV light (residence time). The new end‐caps were first used in the field in 2007 as part of the expansion of the Mesita Azul program to 100 households in Baja California Sur, Mexico.
Expand the UV Tube’s impact by strengthening partnerships
IMTA. As part of Phase II, IMTA undertook three important responsibilities: to increase monitoring of the 15 tUVos and improve their design based on user feedback (see next section); to establish the capacity to validate UV systems in the lab; and to develop information and promotion materials for the UV Tube.
Although IMTA has several qualified laboratories that test for waterborne bacteria and viruses, IMTA did not have the capacity to test for the MS2 virus used in the UV dose measurement technique. As an effort to expand IMTA’s role in the UV Tube project, Forest Kaser (P3 UV Tube team member) traveled to Cuernavaca in the summer of 2006 to transfer UC Berkeley’s UV dose measurement knowhow to IMTA. Forest and IMTA researchers assembled a UV dose measurement setup and built a collimated beam apparatus to allow determination of UV dose (J/m2) from the MS2 virus reduction.
IMTA developed a UV Tube video and a brochure as part of an effort to promote it among organizations that work in the water sector and community members that might benefit from the technology. The six‐minute video, which was based on the pilot experience generated in Villa Nicolas Zapata, presents the water problem encountered by thousands of communities in Mexico and introduces the tUVo design as an effective alternative to obtain safe drinking water. With images from tUVos installed in Villa Nicolas Zapata and community members operating the technology, the video provides a close look from the user perspective. Apart from creating several promotional DVDs, IMTA hosts the video at their website.1 The brochure focuses more on the technical aspects of the tUVo and is intended to be used as a printed visual aid for meetings with community members and institutions interested in safe water projects.
Fundacion Cantaro Azul. In the summer of 2005, four Berkeley students funded by the UNIDO‐MOT International Research Program installed 24 UV Tubes in rural households in Baja California Sur, Mexico. As part of their pilot project, the team conducted detailed water quality analysis, follow up interviews with users, and surveys of household socioeconomics. The field study results showed that the UV Tube allowed families to access safe drinking water. Furthermore, the team determined that the UV Tube fitted with local customs and recommended the development of a project to expand the installations of UV Tubes to other households in the region.
This situation motivated Ian Balam (sociologist and local entrepreneur) and Fermin Reygadas (P3 UV Tube team member) to establish a non‐profit organization, named Fundacion Cantaro Azul, with the mission of designing and implementing safe water and hygiene programs. The new organization provided the P3 team with an opportunity to go beyond its original objectives in Baja California Sur, Mexico.
The P3 team and Fundacion Cantaro Azul developed an implementation program for the Mesita Azul, which consists of six stages: the Regional Needs Assessment to gather the necessary information to adapt the program to the local environmental and socioeconomic conditions; the Community Diagnosis to analyze the drinking water quality, assess the viability of the program, and plan the implementation logistics; the Presentation of the drinking water quality results and the Promotion of the Mesita Azul as an effective safe drinking water alternative; the Installation of the Mesita Azul in households that signed up to participate in the program; a Follow Up visit to tie up any loose ends, and a Final Evaluation visit 6‐12 months after the installation to measure the project’s impact, fix any problems, and obtain user feedback to improve future programs. UC Berkeley Design for Sustainability students greatly contributed to the development of survey tools and standard operating procedures for the Regional Needs Assessment and Community Diagnosis stages.
Evaluate the performance of the UV Tube in the field
IMTA. One of the challenges noted by IMTA researchers in their preliminary field work was that, while sufficient funding was provided in Phase I for field study supplies, they were unable to provide adequate follow‐up and evaluation of installed UV Tubes due to lack of funding for project management. Thus Phase II funding was allocated to improve the management of the field study. The evaluation visits carried out by IMTA researchers allowed them to identify the main barriers and motivations that led families to adopt or not the UV Tube as a method for accessing safe drinking water. In a mid‐term evaluation visit, IMTA researchers noticed that the initial location of the UV Tube had caused several families to abandon its use due to the inconvenience of filling up the inlet bucket, which was placed in a shelf mounted 6ft high in a wall. Two weeks later IMTA researchers returned to the community to reinstall the inlet bucket shelf at a height easily accessible to everyone in the family. Such intervention alone led to an increase in sustained use in the UV Tubes from 25% to 54% of the families.
Fundacion Cantaro Azul. With support from the P3 award and other funding partners, the UC Berkeley team and Fundacion Cantaro Azul installed 14 Mesitas Azules in a rural community of Los Dolores, Baja California Sur, Mexico. The installation was carried out as part of a comprehensive implementation program that included a needs‐assessment survey, a water‐and‐health educational module, and two follow up visits.
The Mesitas Azules took certain elements from the AquatUVo, but gave greater importance to aesthetic and ease‐of‐use design elements. The AquatUVo was a table‐top system, whereas the Mesita Azul (as it Spanish name spells out) included a blue table that holds the UV disinfection chamber underneath, while providing a dedicated space for the disinfected water in a 5 gallon stored below it. The nice blue table added US$20 to the capital cost of the UV Tube (total cost of US$90), but also produced a great response among the rural households, whom considered the Mesita Azul a valuable asset both for its water disinfection capacity and its aesthetic appeal. In fact, the P3 team attributes the high demonstrated willingness to pay of users (US$40 per system) to the attractiveness of the Mesita Azul.
Follow up visits showed a great acceptance of the Mesita Azul. During the first six months all the families that received a system reported using it on an ongoing basis to meet their drinking water demands. In a final visit, one year after the installations, only one family had stopped using the Mesita Azul (92% sustained use). Furthermore, users had extensively recommended the Mesita Azul to their neighboring communities. This facilitated the next round of installations carried out by Fundacion Cantaro Azul in 2007, which extended the Mesita Azul program to 100 households in Los Dolores.


The P3 UV Tube team started the Phase II activities by improving the laboratory validation setup. With a 500 liter tank, a leveled base to mount the UV Tubes, and new laboratory techniques, we were able to speed up the testing process by a factor of four. This increased capacity will allow our team to test the performance of more UV Tube designs and to test each design under different conditions, including water at different levels of absorbance and at various flow rate regimes. In order to fully take advantage of our improved testing capacity we will need to recruit new students and develop a research agenda that includes our field partner needs.
As part of our efforts to improve the UV Tube, we learned that ease‐of‐use and aesthetic design elements played an important role in increasing UV Tube acceptance and sustained use rates for both IMTA and Fundación Cántaro Azul field studies. Although incorporating these elements adds up to the construction costs, we have come to believe that these are crucial to reach the final goal of improving people’s health through sustained use of safe drinking water interventions. Furthermore, in many cases such ease‐of‐use and aesthetic elements have the potential to raise household’s willingness to pay, and thus offset their additional cost.
IMTA’s experience in Villa Nicolas Zapata also brought to light certain limitations of incorporate users in the construction process, especially for projects that seek to scale up the UV Tube. Training users can be time consuming and –even when working under supervision– not all users are skilled enough to construct UV Tubes of adequate quality. When training and repair costs are included, UV Tubes constructed by users can end up being more expensive than those constructed by paid dedicated staff. If a project has the explicit objective or mandate to incorporate users, then the construction process should be simplified, either by modifying the UV Tube design or by delegating certain construction steps to skilled individuals. One feasible alternative is to select some community members with certain technical skills to construct the UV Tubes for the families in the rest of the community or even to train them to construct UV Tubes for a whole region as an income generating activity.
Although UV Tubes can be easily constructed with local materials and labor, there are various opportunities in using wholesale distributors and industrial manufacturing that can lower UV Tube costs considerably. For instance, the 14 Mesitas Azules that were constructed by Fundación Cántaro Azul staff with materials available in local hardware stores ended up costing US$90 each. Whereas the new round of Mesitas Azules that will be constructed by purchasing materials directly from wholesale distributors and by outsourcing the manufacture of end caps and the blue table to a plastic injection factory in mainland Mexico will cost US$60. We consider that it is important to seek a balance between ‘locally available and generic products’ vs. ‘wholesale distribution and custom‐manufactured parts’ that permits a reduction of UV Tube costs while at the same time allows for UV Tube to be repaired locally and independently of the implementing organization.
With respect to our partner organizations, we believe that IMTA and Fundación Cántaro Azul can play an important role in expanding the impact of the UV Tube in Mexico. Since IMTA is an institution dedicated to research and development, dissemination, and regulation, its contribution to the UV Tube project is likely to be focused on developing and validating new designs, creating educational and promotional materials, and supporting organizations with knowledge transfer and field evaluation studies. In the case of Fundación Cántaro Azul, its mission and structure provides it with the flexibility of carrying out R&D, dissemination, and implementation activities. Being an independent organization, its main challenge will be to secure enough resources to expand its impact to communities outside the state of Baja California Sur, Mexico. When considering its expansion, Fundación Cántaro Azul will have to decide whether it should open new branches that will be solely responsible for implementing UV Tube programs, or if it will partner with local organizations that already have staff and resources operating in the field. We recommend the latter both to reduce costs and to increase the project’s potential for sustained impact.
One of the UV Tube team’s most important contributions to sustainability is probably the push for inclusion of more sustainable design and appropriate technologies curriculum in the School of Engineering at UC Berkeley. Thanks to the P3 inspiration and funding, these curriculum changes are underway and the UV Tube project team members have been major players in making this happen. The UV Tube has taken on an important pedagogical role in preparing students to confront global problems, consider the environmental, economic, and cultural sustainability of projects; to work in interdisciplinary teams; and to value public service. The UV Tube has been a case study in four UC Berkeley classes, a design project component in two UC Berkeley classes, has been presented at various conferences and events, and is the subject of two peer‐reviewed papers and four masters theses. UV Tube team members have gone on to found two non‐profit organizations: Fundación Cántaro Azul in Baja California Sur focusing on integrated household drinking water treatment with the UV Tube, and Sustainable Organic Integrated Livelihoods (SOIL) working in Cap Haitian, Haiti on promoting ecological sanitation and simple drinking water treatment methods, including UV. Another team member, Rachel Peletz, has started her professional career as an International Technical Advisor for the Centre for Affordable Water and Sanitation Technology in Calgary, Canada. Furthermore, several aspects of the UV Tube project have been taken on by various engineering teams at other universities and by individuals, all working to make UV a viable option for the developing world.

Journal Articles:

No journal articles submitted with this report: View all 1 publications for this project

Supplemental Keywords:

point‐of‐use water disinfection, ultraviolet disinfection, drinking water, drinking water treatment, UV treatment, alternative disinfection methods, sustainable development, microbial risk management, curriculum design, appropriate technology, water, ultraviolet, point‐of‐use
, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Water, TREATMENT/CONTROL, POLLUTANTS/TOXICS, Sustainable Industry/Business, Chemical Engineering, Environmental Chemistry, Sustainable Environment, Arsenic, Technology, Technology for Sustainable Environment, New/Innovative technologies, Water Pollutants, Drinking Water, clean technologies, detoxification, environmental sustainability, green engineering, other - risk assessment, adsorption, arsenic removal, treatment, drinking water distribution system, activated carbons, UV tube, drinking water contaminants, drinking water treatment, UV light emitting diodes, drinking water system, green chemistry

Relevant Websites:

UV Tube Project
Fundacion Cantaro Azul
Photo‐Documentary of the UV Tube Project
EPA P3 Award: Shedding Light on Clean Drinking Water (Spring 2006)
Berkeley’s Technology Breakthrough Competition: The Greatest Social Impact Award (Fall 2005)

Phase 1 Abstract
Phase 1 Final Report

P3 Phase I:

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