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Water is Life, and We are Running Low

Posted on 22 December 2015 by Sydney Todorovich

Every day you and I require at least 50 liters of fresh water in order to meet our basic needs (drinking, bathing, cooking, etc).[1] Any person anywhere in the world has this same requirement. Yet one third of the world’s population lacks access to this basic human right; they lack access to basic sanitation or clean water.[2]

Seventy percent of our world is covered in water, 2.5% of which is fresh water, and only 1% of this freshwater is easily accessible.[3] This breaks down to 0.007 percent of the world’s water being available to sustain 6.8 billion people in all facets of life.[3] Over the past one hundred years, our global water consumption has tripled, and current water demand continues to double roughly every 21 years.[4] If this trend continues, an estimated two thirds of the world’s population will have difficulty accessing safe, fresh water by 2025.[5]

This begs the question – what are we doing about it? The following offers a snapshot of a few of the projects being conducted around the world to address this problem.

Different regions face different challenges in accessing fresh water. Some areas border large bodies of salt water and have insufficient access to fresh water, while others are landlocked and see little rain, and still others have access to fresh water, but the lack of sanitation infrastructure means the water is not considered potable.

Desalination

Areas that have access to saltwater can focus their research and development on desalination projects. Large-scale desalination plants are unfeasible because of the amount of energy (and money) they require to run. However, recent advancements have made these plants more feasible for the countries that can afford them. For example, the Sorek plant in Israel (the largest desalination plant in the world) designed their plant to use larger sized pressure vessels in the reverse osmosis process in order to decrease energy consumption. This plant, which cost $500 million USD to build, pumps out 624,000,000 liters of potable water daily and is able to sell 1,000 liters for about $0.58 USD.[6] The USA is scheduled to open their own large-scale reverse osmosis desalination plant in San Diego this year.[7]

Singapore, a world leader in water processing, has been exploring the use of electrodialysis in desalination. This process removes chloride and sodium ions from water using electrical charge attraction, and would cost less than half of what revere osmosis does to produce fresh water.[8] Other methods of desalination that are being explored are forward osmosis (using a different highly concentrated solution to pull water out of saltwater)[7] and membrane biomimicry (using aquaporins in membranes to extract water).[8] Although membrane biomimicry would require significantly less energy to run, it is still not as easily scalable, it is cost prohibitive to produce, and its durability is in question.[8]

One of the bigger concerns with desalination is the salt waste that is produced, and whether putting the salt back in the ocean will negatively impact the ecosystems surrounding the plant.[7] Reports of increased salinity (from 35,000 ppm to 50,000 ppm) in the Persian Gulf surrounding the desalination plant in Saudi Arabia suggests this may be a real problem that requires addressing.[7]

Water Filtration

Every year diarrheal disease kills approximately 760,000 children under five years old.[9] The majority of these cases could be prevented by access to safe drinking water and proper sanitation.[9] Creating a cost effective, mass producible, portable, easy to use, and reliable water purification system is something that is desperately needed worldwide, especially in developing countries. Three especially interesting and innovative products that have been developed (or are in the process of being developed) to help combat this issue are the “drinkable book”, a low-cost water filter, and Slingshot.

The Drinkable Book™ is literally a book filled with paper that contains nanoparticles of silver and copper.[10] As the water is being filtered through the paper, the bacteria absorb the silver and copper, causing them to die. This paper has been tested both in the lab and in the field (including water that had raw sewage dumped into it), and the paper removed greater than 99% of the bacteria within the water. [10] Each page has instructions printed on it directing the person how to use the filter properly. One page from this drinkable book can filter approximately 100 liters of water, and one book could filter enough water to last a person four years. [10] The only drawback to this book is that it has not yet been tested on viruses nor protozoa. [10]

Askwar Hilonga is a rural Tanzanian native who studied abroad to achieve a PhD in nanotechnology. He hoped that his education would enable him to create a water filtration device that would help supply clean drinking water to the 70% of Tanzanian households who do not have it.[11] Still in its early stages, the filter shows a lot of promise. It is a sand based filter, and although sand can remove debris and bacteria from the water, Dr. Hilonga added specific nano materials to the filter in order to remove chemical and heavy metal contaminants as well.[11] He recently won a prize of $38,348 USD from the UK’s Royal Academy of Engineering for his innovation. Dr. Hilonga estimates that the price per unit will be considerably less that the initial $130 USD now that he can buy materials in bulk to create the filters. For those families who cannot afford their own filter, Dr. Hilonga has created water stations where people can buy the clean water at an affordable price.[11]

Slingshot is the creation of inventor Dean Kamen, better known for his invention of the Segway. Slingshot is a machine that produces potable water from practically any source through vapour compression distillation and requires no filters to function.[12] Its power can come from electricity if available, from a diesel generator (found at many remote hospitals), or in very remote areas it can use a Sterling engine, which is fueled by any combustible source.[13] When designing Slingshot, Mr. Kamen wanted it to be able to run for 5 years without maintenance, use less than a kilowatt of power (less than a hair dryer), generate 1000 liters of clean water per day, and require no pipelines, pre-treatment or consumable materials for the filtration.[13,14] Mr. Kamen has finished his creation, and has created a documentary about it, so we will just have to wait and see if this machine works as well as its creator hoped it would.

Making Water From Thin Air

What if there was a billboard that could use humidity to create clean drinking water? Sounds crazy. It exists. In Peru, the University of Engineering and Technology (UTEC) designed a billboard that can condense water from humidity. This billboard is located in one of the driest places on earth – Lima, Peru. Lima receives practically no rainfall even though it experiences average relative humidity of 83.9%.[15] Lima’s population is approximately 7.5 million, 700,000 of which do not have access to clean drinking water. [16] In response to this need UTEC created the billboard, which harbours five condensers that act to cool the air and thus create liquid water. The water is subject to reverse-osmosis purification before it can be stored in the 20L storage container at the base of the billboard. It is capable of producing 96 liters of water per day for local residents. And although the billboard cost a mere $1200 USD to build, it has the ability to offset the construction and energy costs through advertising on the billboard itself. Whether more will be created, or whether the design will be available for sale to other countries or industries is yet to be seen.[16]

References

1. Gleick P.H. (1996). Basic water requirements for human activities: Meeting basic needs. Water international, 21; 83-92.

2. USAID. (2015). Water and sanitation. Retrieved from: www.usaid.gov/what-we-do/water-and-sanitation

3. National Geographic. (2015). A clean water crisis. Retrieved from: environment.nationalgeographic.com/environment/freshwater/freshwater-crisis/

4. Chakravorti, B. (2015). Is clean water the new oil? Retrieved from: fletcher.tufts.edu/MIB/Ten-Questions/Q6-Is-clean-water-the-new-oil

5. Scanlon, J., Cassar, A., & Nemes, N. (2004) Water as a human right? IUCN Environmental Policy and Law Paper No. 51

6. MIT Technology Review. (2015). Megascale Desalination: The world’s largest and cheapest reverse-osmosis desalination plant is up and running in Israel. Retrieved from: www.technologyreview.com/featuredstory/534996/megascale-desalination/

7. Belton, P. (2015). Can making seawater drinkable quench the world’s thirst? BBC Business. Retrieved from: www.bbc.com/news/business-34478052

8. McKeag, T. (2014). Do tilapia and mangroves hold secrets to desalination? Retrieved from: www.greenbiz.com/blog/2014/09/03/desalination-how-nature-can-guide-us-water-fit-drink

9. The World Health Organization. (2013). Diarrhoeal disease. Fact sheet No330. Retrieved from: www.who.int/mediacentre/factsheets/fs330/en/

10. Webb, J. (2015). Bug-killing book pages clean murky drinking water. BBC Science. Retrieved from: www.bbc.com/news/science-environment-33954763

11. BBC. (2015). Tanzanian low-cost water filter wins innovation prize. Retrieved from: www.bbc.com/news/world-africa-32973591

12. Melanson, D. (2008). Dean Kamen aims to clean water, generate electricity with Slingshot machine. Retrieved from: www.engadget.com/2008/04/23/dean-kamen-aims-to-clean-water-generate-electricity-with-slings/

13. Science http://science.howstuffworks.com/environmental/green-tech/remediation/slingshot-water-purifier3.htm

14. Kamen, D. (2010). What’s behind my curtain? TEDMED 2010. Retrieved from: www.tedmed.com/talks/show?id=6994

15. Wikipedia. (2015). Lima. Retrieved from: en.wikipedia.org/wiki/Lima#Climate

16. Smith-Strickland, K. (2013). A billboard that condenses water from humidity. Popular Mechanics. Retrieved from: www.popularmechanics.com/science/green-tech/a8875/a-billboard-that-condenses-water-from-humidity-15393050/

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