Advancing Sustainable Drinking Water Solutions
The UN Millenium Development Goals and many international aid agencies have launched efforts to address access to clean water problems of billions of people worldwide. However, these efforts focus exclusively on eradicating biological agents of waterborne diseases to provide safe drinking water. To date, no appropriate methods have been developed to address chemical contamination from toxic substances using locally available resources. In developing countries, the majority of pesticides used are chemicals that had been banned or heavily restricted in developed countries due to their damaging ecological and human health effects.
Adsorption by activated carbon is widely recognized in the industrialized world as an effective technology for removing hazardous organic substances, including pesticides from drinking water. This technology, however, is not yet available in rural, remote, and lesserindustrialized regions, exposing a large number of the population to elevated concentrations of harmful agrichemicals through their drinking water. On the other hand, indigenous cultures have long practiced charcoal water filtration. This Aqueous Solutions research project, a segment of a larger and long-term initiative, builds upon this traditional water filter system as a sustainable, low-cost and locally-derived alternative to modern industrial activated carbons for the removal of hazardous organic chemicals from drinking water
The first phase, completed in August 2009, focused on research that assessed the potential of selected indigenous charcoal as low-cost adsorbents of agrichemicals. The charcoal materials were collected throughout Southeast Asia. It was found that indigenous charcoals produced under certain conditions might be effective for removing pesticides from drinking water; however, the feedstock material used to produce the charcoal, as well as the thermal treatment conditions, strongly influenced its effectiveness. The research suggested a strong potential for the project’s success given further investigation into the existing range of indigenous charcoal materials, facilities and processes by which charcoal is manufactured in poor communities.
The second phase of the research was initiated with the support of the IBoP Asia grant. The inquiry delved deeper in the assessment of charcoal samples collected in the field. Charcoal was also manufactured in the laboratory with field feedstock under a range of conditions typical to indigenous charcoal production systems. This phase of the research was able to do the following: a) determine the conditions typical for indigenous charcoal production so that the charcoal produced could be reliably employed in drinking water filtration applications targeting pesticides, and b) evaluate the potential for optimizing traditional charcoaling processes to produce enhanced adsorptive carbons. The grant from iBoP Asia also enabled the project team to continue monitoring the microbiological quality of the water produced by the prototype charcoal filter systems installed by Aqueous Solutions in Pun Pun Sustainability Learning Center in Chiang Mai Province, Thailand.
The team conducted in-depth observations of thermal treatment regimes typical of traditional indigenous charcoal-making (pyrolysing biomass or heating it in the absence of oxygen strongly influences the molecular character of the charcoal and, thus, its adsorption capacity and characteristics). An ongoing partnership with the Pun Pun Sustainability Learning Center facilitated the observation of charcoal production using one of the simplest methods commonly employed in BoP communities -- the single drum kiln method. Several runs of charcoaling established a baseline for typical thermal treatment parameters. Important relationships among feedstock aging, peak temperature and heating rate were also observed.
The project also partnered with the Wood Energy Research Centre to facilitate observation of traditional charcoal-making at a medium-scale using typical BoP village kiln designs.
This allowed the project team to take the next steps in evaluating the performance of selected charcoal and clearly identify the charcoaling conditions that will allow the reliable production of highly effective water treatment materials in a BoP community setting. Seven months were spent on planning experiments, acquiring materials and reagents, and designing and constructing a BoP community-style test kiln for charcoal production in order to carry out the research and development component of the project.
The next phase involved monitoring and training activities to disseminate project findings. It also publicized the production of enhanced indigenous charcoal materials as well as the implementation of traditionally designed, robust and inexpensive household filter systems specifically targeting harmful agrichemicals.
Risks, Problems, and Barriers
Josh Kearns, principal investigator of Aqueous Solutions, observed that one of the barriers to innovation at the BoP is a “disconnect” between the kinds of technologies that can really service the BoP and the research done by advanced institutions in the developed world. Aqueous Solutions’ approach of actively connecting with local areas and communities seeks to fill the gaps in scientific research and practical engineering, with the guiding philosophy that BoP ownership
and operation are key to the sustainability of an innovation. The project team saw that there are many existing indigenous solutions that meet the needs of the BoP. However, in order to make these solutions replicable, sophisticated analytical methods, laboratory instrumentations and highlevel scientific expertise are still required. For example, the characterization of indigenous charcoal and the assessment of the influence of different charcoal production conditions on the charcoal’s capacity to remove water contaminants require high-tech equipment and knowledge.
Benefits, Outcomes and Reach
One important result of this research project is the monitoring study on charcoal manufacturing. There are no existing published studies and in-depth analyses of thermal regimes during indigenous charcoal manufacturing. The monitoring study alone represents a significant contribution to the scientific literature related to biomass pyrolysis. The monitoring study revealed a novel charcoal kiln operator technique already in use locally in Thailand, where a small electric fan is employed to increase airflow to the kiln for specific short periods during kiln firing. The net effect of such enhanced aeration is a rapid and dramatic increase in temperatures within the kiln over short periods of time.
It is hoped that future developments in the project will further the potential of indigenous charcoal materials as low-cost analogs that can be used and produced by poor communities for their water treatment systems.The community, in the process, gained more knowledge on the importance of having clean water and the use of water purifying facilities. This will enable them to engage more actively in future campaigns, and in other projects related to water resource management.
The realization of the value of collaborating with local institutions is a key lesson derived from this project. Working with the Pun Pun Sustainability Learning Center and the Wood Energy Research Centre, among others, significantly provided opportunities for direct observation of traditional charcoal making techniques, and for in-depth exploration of various local operator techniques and their influence on the charcoal products through operator surveys and anecdotal evidence. This collaboration also allowed the project team to establish important connections with local charcoalers who are expected to best facilitate the dissemination of the research findings and the adoption of the process once ready
The project is still in its preliminary stages. The ongoing testing and monitoring of indigenous charcoal production methods and kiln operations are expected to yield more significant results. Once the viability of these techniques is established, it is expected that millions around the world, especially those at the BoP, would be able to harness this technology.
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