Water Purification Christa Bergquist Emily Mekas Robbie Linklater
Why is clean water such a big deal? It is truly amazing how many deaths are caused by a lack of clean water. Over 15% of the earth’s population does not have access to clean and useable water. Estimates show that nearly 5,000 children die from diseases caused by unhealthy water each day. This number would decrease dramatically if there were water purification methods more readily available to people in impoverished countries.
Even though the world is about 70% water, only about 3% freshwater and useable for drinking, cooking, etc The problem is that there is plenty of water in some countries, such as Canada, but areas like northern Africa and the Middle East suffer from a large shortage. Over half of the world’s useable water is located in just 9 countries. Those countries are: the United States, Canada, Colombia, Brazil, Democratic Republic of Congo, Russia, India, China, and Indonesia. In many instances, economic as well as political barriers prevent access to water in areas where it is otherwise available.
The majority of the world’s water is the oceans, and therefore the salt water is unusable without desalination treatment. Only 3% of the planets water is fresh water, and most of that is frozen in the form of ice or snow. Drinking water only accounts for a small portion of the total amount of clean water needed. In fact, this household water only accounts for less than 5% of total water use. Along with sanitation, water is needed for industry and agriculture. Developing methods of ensuring sufficient water supplies poses engineering challenges of the first magnitude.
Where does our water supply come from? Between digging wells and building dams, engineers are prime providers of methods for filtering and decontaminating water. To meet current needs, these methods will need to become more advanced.
One approach used in larger countries is to redirect the flow of water from areas where it is abundant to where it is in short supply. These diversion projects provide some relief for cities, but it is short-term, and this method will not be able to meet agricultural needs. Also, diverting water to some people often means less for others and can become an explosive political issue.
Desalination is used in many regions, but particularly in the Middle East. Saudi Arabia alone accounts for about 10% of global desalination.. Modern desalination plants utilize reverse osmosis, which uses a thin membrane to separate the salt. More than 12,000 desalination plants operate worldwide. However, desalination plants are expensive to build and require large amounts of energy to operate, making desalination suitable mainly in rich countries. Therefore, it has limited value for impoverished countries, where water supply problems are most serious.
What other technologies will provide clean water? Technologies are being developed to improve wastewater recycling and sewage treatment so water can be used for things such as irrigation or industrial purposes. Recycled water could even resupply aquifers. However, effective purification methods and rigorous safeguards are necessary to preserve the safety of recycled water.
New technologies would lower energy use and costs. This might help desalination’s contribution. A potentially useful new method, called nano-osmosis, filters out salt using tiny tubes of carbon. Experiments show that these tubes, called nanotubes because of their size on the scale of nanometers, make excellent filters. Even with these advances, it seems unlikely that desalination alone will be able to solve the world’s water problems. Other approaches will be needed.