This blog post examines why safe drinking water remains inaccessible for many and explores the potential and limitations of appropriate technology to address this issue.
What happens if you drink contaminated water?
Countless people worldwide still drink contaminated water. According to the World Health Organization (WHO), approximately 29% of the global population still lacks access to safe drinking water. In underdeveloped countries, particularly in Africa and South Asia, walking for hours daily to fetch water is a routine part of life. Yet, even water obtained through such arduous, time-consuming efforts is often unsafe, exposing people to various diseases from consuming contaminated water. Consuming contaminated water makes people susceptible to infectious diseases like diarrhea and cholera. Children, in particular, face a high risk of death from dehydration caused by frequent diarrhea.
UNICEF reports that approximately 1.3 million children under the age of five die from diarrhea each year, making it the second leading cause of death among infants and young children. This demonstrates that the clean water we easily enjoy is not a given for everyone. Supplying water purification devices suitable for these regions lacking safe drinking water is a critical task. This article introduces two appropriate water purification technologies designed to address water scarcity and examines how each technology reduces risks from contaminated water.
LifeStraw Portable Water Filter
The first water purification technology introduced is the LifeStraw portable water filter, developed by Vestergaard Frandsen. This device resembles a straw, making it easy to carry and use anywhere. When water is drawn through the LifeStraw, its internal porous fibers, measuring 0.002µm in size, filter out bacteria and parasites. According to tests, the LifeStraw can filter out 23 types of bacteria by over 99.9999% and 7 types of parasites by over 99.9%. As such, LifeStraw is a device that can prevent various diseases that can be contracted simply by drinking contaminated water. One LifeStraw can filter approximately 1,000 liters of contaminated water.
This product gained significant attention and widespread adoption, being selected as Esquire’s “Innovation of the Year” and Time’s “Best Invention of the Year” in 2005. Furthermore, the LifeStraw Family, developed for larger groups, uses gravity to filter approximately 18,000 liters of water. This allows a family of five to have safe water for about three years without electricity. It meets the water quality standards set by the U.S. Environmental Protection Agency (EPA).
However, LifeStraw has also been criticized for not being a fundamental solution in water-scarce regions. While priced at around $3, this remains a significant burden for many residents in underdeveloped countries. Furthermore, the device is limited to filtering bacteria and parasites; it cannot remove contaminants like heavy metals or chemicals.
Water Purification Technology Utilizing Plant Xylem
The second water purification technology introduced utilizes the natural filtration method of plant xylem. Boutilier et al. (2014) reported that the pit structures within the xylem can be used to filter pathogenic bacteria. Plants absorb and transport water through their xylem. Specifically, the xylem of some plants, such as conifers, contains tracheids with pit structures that act to filter out air entrained in the water. Research has confirmed that the pit membrane of this structure can filter out bacteria like E. coli.
In experiments using coniferous tree filters, a 99.9% filtration rate against E. coli was demonstrated. A 1 cm² tree filter can purify approximately 4 liters of water per day, sufficient for one person’s daily drinking needs. Since filters can be made simply by stripping the bark from branches, this technology holds potential for easy implementation in underdeveloped regions. Unlike existing water purification devices that require external support, this technology utilizes the tree itself, offering the advantage of enabling local self-sufficiency.
However, this technology has not yet been commercialized and requires several improvements. Research on tree species present in water-scarce regions and additional verification of the filter’s lifespan are essential. If these issues are resolved, residents of water-scarce countries could obtain safe water using simple plant filters in the future.
What is Appropriate Technology?
Both of these water purification technologies are prime examples of appropriate technology. Appropriate technology refers to technology designed considering the economic, social, and cultural characteristics of the location where it is used. It is low-cost, easy to use, reduces dependence on external resources, and is environmentally friendly. Both LifeStraw and plant-based water purification technologies are specifically designed for the unique environments of water-scarce countries, holding great potential to save lives and improve quality of life.
As appropriate technology advances, more people are gaining access to clean water, and its scope is expanding beyond simple water purification into energy, health, and education sectors. Recalling the original purpose of technology, if appropriate technology continues to advance and spread, the survival and well-being of many developing countries and underdeveloped regions will be significantly improved.
Thus, the development of safe water supply and sustainable water purification technology is not merely an essential element for survival, but can be considered an essential technology for safeguarding basic human dignity and quality of life.
