Green Technology: Combating shortages, conserving water
It is said that man can live without food for up to three weeks but will perish in just three days without water. This illustrates just how important water is to us. Water is used in almost every aspect of our day-to-day lives, from showering to washing the dishes. In just one year, the world uses three trillion gallons of water, equivalent to 1,703 litres per person.
One of the major challenges being faced worldwide is a water shortage due to the increase of populations. To combat this shortage, countries have come up with a variety of approaches including conserving, recycling and desalination.
In efforts to conserve water, nations raise the price of potable water, with results showing savings of as much as 12 per cent. One of the recycling methods that has been employed is filtering, where two layers of filters are used. This can be carried out using fishes as a first layer filter; the fish eat up dirt, shells and other particles. The water then goes through another filter before chemicals like chloride are added to make the water consumable.
By using biological mechanisms like fish, the filtering process has minimal impact in terms of waste, reduces the harm to the environment and also does not involve any heavy machinery or gadgets that will incur added cost.
Desalination: There is much debate across the world on desalination mostly because the by-product of the process – salt – is put back into the ocean, increasing the sodium content, creating an inhospitable environment for sea life.
Recently, a new, greener method of desalination has been developed. This method uses evaporation and condensation with an external energy input that can include waste energy or solar energy.
Another innovation that has been developed is the process of replacing the use of pre-treatment desalination chemicals with a mechanical process called ProGreen, which is the world’s first green reverse osmosis system for water desalination.
Before a desalination process is carried out, the seawater intake is treated to change its chemistry. During this time, some chemicals may end up in the brine waste product that goes back into the ocean and those that come in contact with these chemicals may suffer side effects. Using ProGreen eliminates this problem and it also optimises energy consumption.
Water management: The GE Singapore Water Technology Centre located in the National University of Singapore campus is an example of a facility that is committed to water management.
The centre plays a pivotal role in developing new outcomes for low-energy seawater desalination, water reclamation and efficient water reuse through GE scientists who are based there. The centre also serves as a platform that will help accelerate research and industry innovation that is crucial in water treatment. The Singapore government aims to make the country a global hydrohub, and the centre will certainly pave the way for many breakthroughs.
Recently PUB Singapore, a statutory board under the Singaporean Ministry of Environment and Water Resources, signed a memorandum of understanding with the International Desalination Association to explore opportunities in order to work together in water training and education.
It is hoped that with the signing of the MOU, both parties will come up with educational programmes that will benefit the desalination community both in Singapore and across the world. It will also explore development opportunities for the water community at large specifically in water reuse practices and technologies.
Handling water shortages: Europe is also currently facing a major water crisis and it is expected that between 16 and 44 million people in southern Europe will suffer from water scarcity by the year 2070.
As the water supply system that is presently used requires high investment costs and high energy consumption, a project called REFRESH has been established as a green solution for the transportation of fresh water by sea to combat the water stress problem that the continent is facing. REFRESH is a cost-effective and energy-efficient solution that uses the concept of recyclable flexible plastic barges that are towed by tugboats.
There are also plenty of other methods being used to handle the global water crisis. Solar distillation is one example and it is one of the oldest, as it dates back to 1872, and is also the most common method of water purification.
The process involves sea water being placed inside shallow tanks that are heated by the sun. The evaporated water vapour is then trapped by collector plates, condensed, and returned to the reservoir section of the unit as fresh water.
No external power is used by these solar stills to remove salt from the water but rather, the natural evaporation cycle of the water when exposed to the heat of the sun is used. This process is totally portable and can be used even in the remotest location because it does not require any additional man-made energy, just natural resources.
There is a lot that can be done to save water and these are just some examples that are being carried out across the world in order to conserve, recycle and put water to the best use. All it takes is concerted efforts from all parties to raise awareness and safeguard this limited resource that we have been blessed with.