In this blog post, we will look at why we still cannot get safe drinking water and the possibilities and limitations of appropriate technology to solve this.
What happens if you drink contaminated water?
Many people around the world still drink contaminated water. According to the World Health Organization (WHO), about 29% of the world’s population still does not have access to safe drinking water, and in underdeveloped countries in Africa and South Asia, people often walk for hours every day to get water. However, even water that has been painstakingly obtained over a long period of time is often unsafe, exposing people to various diseases due to drinking contaminated water. Consuming contaminated water can lead to infectious diseases such as diarrhea and cholera, and children are particularly at risk of death from dehydration due to frequent diarrhea.
According to UNICEF, about 1.3 million children under the age of five die from diarrhea every year, which is the second leading cause of death in infants. This shows that the clean water we take for granted is not a given for everyone. It is a very important task to distribute suitable water purification devices to these regions that lack a safe drinking water supply. In this article, we will introduce two water purification technologies designed to solve the water shortage problem and examine how each technology reduces the risks associated with contaminated water.
LifeStraw, a portable water purification device
The first water purification technology I would like to introduce is LifeStraw, a portable water purification device developed by Vestergaard Frandsen. This device looks like a straw and can be easily carried and used anywhere. When you suck up water with LifeStraw, the 0.002-µm-sized porous fibers inside filter out bacteria and parasites. According to experiments, LifeStraw can filter out more than 99.9999% of 23 types of bacteria and more than 99.9% of 7 types of parasites. LifeStraw is a device that can prevent various diseases that can be contracted by drinking contaminated water. One LifeStraw can filter about 1,000 liters of contaminated water.
This product was selected as Esquire’s “Innovation of the Year” and Time’s “Best Invention of the Year” in 2005, and has been widely distributed. In addition, the LifeStraw Family, which was developed to be used by more people, can filter about 18,000 liters of water using gravity, allowing a family of five to use safe water for about three years without electricity. This meets the water quality standards of the U.S. Environmental Protection Agency (EPA).
However, LifeStraw is not a fundamental solution for areas suffering from water shortages. Although it costs about $3, it is still a price that many residents of underdeveloped countries cannot afford. Moreover, the device can only act as a filter that removes bacteria and parasites, and it has the limitation of not removing pollutants such as heavy metals and chemicals.
Water purification technology using plant xylem
The second water purification technology is a natural water purification method using the water pipes of plants. Boutilier et al. (2014) announced that the pit structure in the water pipe can be used to filter out pathogenic bacteria. Plants absorb and transport water through the xylem, and the xylem of some plants, such as conifers, has tracheids with a pit structure that filter out air mixed with water. Studies have confirmed that the pit membrane of this structure can filter out bacteria such as E. coli.
In fact, experiments using coniferous wood filters showed a 99.9% filtration rate for E. coli, and a 1cm² wood filter can purify about 4 liters of water, which is enough for one person to drink in a day. Since the filter can be made by peeling off only the bark of the tree branch, it has the potential to be easily used in underdeveloped regions. Unlike existing water purification systems that require external support, this technology has the advantage of being able to be self-sufficient in the local area because it uses trees themselves.
However, this technology has not yet been commercialized and requires several improvements. Research on tree species that exist in water-scarce areas and additional verification of filter life are essential. If these issues are resolved, in the future, residents of water-scarce countries will be able to obtain safe water with a simple plant filter.
What is appropriate technology?
These two water purification technologies are both considered to be representative examples of appropriate technology. Appropriate technology is designed to take into account the economic, social, and cultural characteristics of the place where the technology is used. It is low-cost, easy to use, reduces dependence on external resources, and is environmentally friendly. Both the LifeStraw and plant water pipe water purification technologies are designed to suit the unique environment of water-scarce countries, and have the potential to save many lives and improve the quality of life.
As appropriate technology develops, more people are being helped to obtain clean water, and the scope of this is expanding beyond simply water purification to energy, health, and education. If appropriate technology is further developed and disseminated, many developing countries and underdeveloped regions will be able to improve their survival and well-being.
In this way, the development of safe water supply and sustainable water purification technology is not just an essential element for survival, but an essential technology for protecting the basic dignity and quality of life of humans.
