May 2011

Aquatest Update

The period since the last newsletter has been of crucial importance as the development of the Aquatest System takes shape. The team have been working closely with our manufacturing partners to deliver the Aquatest device and the constituent parts that make up the Aquatest system: the device, a field incubator, an ultra-violet (UV) torch and a cell phone based Water Quality Reporter. The project is now on target for the Validation study, a comprehensive programme of laboratory trials of the device, to commence in June 2011.

Since the last newsletter detailed the work of Rob Matthews in developing the Aquatest Incubator, this time we will be concentrating on the Aquatest device and the UV torch. In the first article John Halliwell reports on the Aquatest device, outlining how it functions as an “all in one” testing format (sample-test-enumerate-disinfect and discard). In the second article, Halliwell reports on the Aquatest UV torch, which is used to read the results of the test, and details how those results give information on relative microbial contamination levels in a given water sample.

The wider aim of the project is to ensure that the learning and knowledge developed across the project is disseminated to the appropriate audiences. With that in mind we will be featuring the work on the cost-effectiveness of water quality monitoring that is being conducted at the University of North Carolina with an article from Jonny Crocker. Finally, we will be continuing the team profile section of the Newsletter with a profile of Bina Shah who joined the project in February 2011 to provide project management support for the the commercialisation strategy of the Aquatest System.

In other news, the Aquatest website has been updated to include new content on the Aquatest system with individual pages devoted to the device, incubator, UV torch and Water Quality Reporter. The working papers section of the website has also been expanded and now includes research reports on the water quality diagnostics sector; more working papers will be added as new research is made available.

As always, we look forward to your thoughts and comments.

John Halliwell, University of Bristol, UK

The Aquatest Device

In our last newsletter we explained that the design for the Aquatest Device had been finalised and contracts were in place for its manufacture. Since then we have been working closely with Kinneir Dufort, Hi Tech Mouldings Limited, and Sepha (the contracted manufacturers for the device), to test the critical performance criteria features of the device in the lead up to the Validation study, which is set to commence in June 2011, and will evaluate the reliability and accuracy of the device for the detection of E. coli in drinking water through comprehensive laboratory trials.

Aquatest Device

What is the Aquatest Device?

Aquatest is an “all in one” testing format (sample-test-enumerate-disinfect and discard) that ensures accuracy, simplicity and safety for the end-user. The Aquatest device is a small, single-use device for testing microbial water quality. It consists of a single plastic sampling and testing unit that is used to test water samples for E. coli (an internationally recognised indicator of fecal contamination).  Aquatest will be sensitive enough to detect one E. coli colony in the 100ml sample. The device holds 100 ml of water and includes an E. coli selective growth medium and a disinfectant. It will be used in the field in developing countries, without electricity or skilled technicians. The device is designed to eliminate direct exposure to media, bacterial cultures and disinfecting chemicals.

How does it work?

First of all, 100 ml of sample water is collected directly in the Aquatest device. A few simple steps mix the selective growth medium and segregate the sample into eleven distinct chambers on the bottom of the device. Upon incubation at 37° C for 24 hours, the number of chambers changing colour indicates the level of E. coli contamination. This colour change is provided by the industry standard MUG reagent which fluoresces under UV light in the presence of E. coli.

Aquatest Device

After incubation, the presence of fluorescence in the chambers gives information about the quality of the water. The more chambers that fluoresce, the greater the contamination. These bands of quality are important as they will show, for example, the relative contamination levels of different sources in an area, rather than just presence/absence of contamination. The information on relative contamination levels can be used to improve decision making by water managers.

The Aquatest device also contains a disinfectant which will be released once the results have been recorded. This disinfectant will eradicate microorganisms that have grown during incubation, thereby enabling safe disposal of the device.

John Halliwell, University of Bristol

The Aquatest UV Torch

What is the Aquatest UV Torch?

The Aquatest UV Torch is a safe, simple to use, handheld ultraviolet light that is used for reading the results from the Aquatest device. It is portable and rugged for use in field settings and provides sufficient UV light to use in varying light conditions.

How does it work?

The Aquatest device works by separating the water sample into distinct chambers at the bottom of the device. Upon incubation at 37° C for 24 hours, the number of chambers changing colour indicates the level of E. coli contamination. This colour change is provided by the industry standard MUG reagent which fluoresces under UV light in the presence of E. coli.

The Aquatest UV Torch is used to read the results of the device enabling the user to see the fluorescence that indicates the presence of E. coli. It is designed using low power UV LEDs, orientated so that they shine directly into the chambers: the design ensures user safety whilst providing enough illumination to easily identify positive chambers. The torch design limits the entry of external light into the chambers and maximizes the brightness of UV LEDs by creating a dark-room effect. It is powered by AA batteries which will last for an estimated five years, whilst the use of cost-efficient LED illumination also gives it a long-term shelf life.

How do you read the results?

As the image to the left indicates, the device chambers are configured into a user-friendly format and the user can use the UV torch to read how many chambers have tested positive for the presence of E. coli. The greater the number of positive chambers, the greater the level of microbial contamination in the drinking water. Aquatest does not give an exact count, but rather provides a range within which the number is likely to lie. An established mathematical model can be used to determine the most likely contamination level - the most probable number or MPN. The MPN provides an estimate of the number of E. coli in the sample and acts as an indicator of relative microbial contamination levels. An easy-to-read MPN table comes with each device that tells the user the level of microbial contamination in the drinking water.                 

This MPN result from the Aquatest gives timely information on relative microbial contamination levels (and associated health risks) to those responsible for water management. The timely information on relative contamination levels can be used for improved decision making. The MPN result can also be fast-tracked to decision makers using the Water Quality Reporter, a cell phone based reporting system.

John Halliwell, University of Bristol

University of North Carolina: Scenarios Work

The Water Institute at The University of North Carolina is investigating current monitoring practices in a variety of settings as part of the Aquatest Project’s push to improve the way water quality monitoring occurs around the world. The objective of the scenarios work being conducted at the Water Institute at UNC is to characterize current monitoring practices, and to analyze the costs and effectiveness of implementing monitoring programs. While acknowledging that there are many actors that play a role in water quality management, this research focuses on governmental or other centralized efforts for monitoring of microbial drinking water quality.

Understanding of current monitoring practices began with a review of published and gray literature, along with interaction with the Aquaya Institute on institutional mapping. This was followed by selecting study countries to represent a range of global monitoring practices using a clustering technique. Data collection through field work was conducted in nine countries during summer 2010 (Cambodia, India, Jordan, Malaysia, Morocco, Mozambique, Peru, South Africa, and Uganda). Since completion of data collection in the fall of 2010, focus has been on data analysis.

During summer 2010, six data collectors traveled around the world to nine developing countries to conduct interviews, collect gray literature and documentation on monitoring, and observe monitoring practices through going on drinking water sampling trips to watching samples being tested for microbiological parameters such as total coliform and E.coli. This work enabled the collection of quantitative data that will feed into cost-effectiveness analysis, and additionally gave insight into the barriers for conducting comprehensive and effective monitoring. These barriers contribute to discrepancies between how monitoring is supposed to occur, and how it is carried out in practice.

Cost analysis will include marginal costs associated with monitoring: test materials (test tubes, broth, etc), direct labor costs (sample collector time, laboratory technician time), and transportation costs (vehicle maintenance, gas). The approach for collecting data through to a cost estimate is best visualized with a dendrogram. Raw data collected from interviews and gray literature is first converted into quantitative parameters that contribute to analyzing the three elements of cost (test materials, labor, transportation). Many parameters were collected from a sampling of interviews. These data points were extrapolated to a country-wide level to yield a cost estimate that applies to the entire country. Finally, to reach a cost estimate, the three components of cost were multiplied by unit values (e.g. material cost per test, salary of laboratory technicians and samplers, and cost per mile traveled). The exact approach for analyzing costs of monitoring varies as the raw data available varies.

Characterization and cost analysis of monitoring in India focused on three states that represent a variety of settings, since characterizing practice for all of India is infeasible given that practice is unique from state to state. The three focus states were Uttar Pradesh, West Bengal, and Maharashtra. For these states, monitoring programs are  unique for    different settings; specifically rural areas, small urban areas, and the largest urban areas are all monitored differently from each other. Rural areas are generally monitored by the state public health department by testing samples at distributed laboratories using the multiple tube MPN method (although in Uttar Pradesh, community-based volunteer teams are also equipped with H2S presence-absence field kits). Small urban areas generally do not have dedicated water quality laboratories, and send samples to state public health department laboratories, or other laboratory networks to be tested using the multiple tubes MPN method. The largest cities in each state characterized have dedicated water quality laboratories based at treatment plants, and test samples using the multiple tube MPN method or using the membrane filtration plate count method.

For each monitoring scenario described, there is a frequency of sampling and number of samples that are supposed to occur, either based on national level guidelines in India, or based on state level guidelines or requirements; this number is called the “theory” for a given scenario. The actual number of tests completed per year often varies from theory for a variety of reasons such as resource constraints; this number is called the “practice” for a given scenario.

The above figure displays an estimate of the number of tests conducted in each setting in all three states characterized, shown as a comparison between practice and theory. The above numbers are based on preliminary analysis of data collected during summer 2010, and will be refined for any final reporting or publication. These preliminary results indicate that in India there exist many obstacles to comprehensive drinking water quality monitoring, especially in the less dense rural and small urban areas.

Future work to be completed by summer 2011 includes refining the analysis for countries already analyzed (India and Jordan), completing analysis for an additional four countries (Cambodia, Peru, South Africa, and Uganda), and combining the work conducted at the Water Institute into a final report.

Jonny Crocker, The Water Institute at UNC, USA

Aquatest team profile

University of Bristol: Bina Shah

Aquatest has the potential to make a transformational change to the lives of people in the developing world. It was this premise that attracted Bina Shah to the project. Bina joined the team at the University of Bristol in February 2011, and provides project management support for the development of the commercialisation strategy of the Aquatest System. A key part of that role is interfacing with businesses, public bodies and other organisations. She is also responsible for providing expertise and guidance on marketing communication strategies and tools.

Bina came to the Aquatest project having managed the University of Bristol’s Nanoscience and Quantum Information Research Theme, working to deliver a number of successful international symposia and workshops. Prior to this role, Bina worked for Hewlett-Packard and brings with her a unique mix of international experience in external and organisational marketing communication, with a specialty in the alignment of company vision and strategies.

Having grown up in Kenya, India, and England, and worked in both Europe and the USA, Bina has experienced a variety of different countries and cultures and is enthusiastic to contribute to the success of an international project.

John Halliwell, University of Bristol

• Banner Photos: WaterAid/Marco Betti

• PDF of May 2011 Newsletter (832 kb)

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