Can we solve the world’s water crisis with ocean water?

 

Can we solve the world’s water crisis with ocean water?

We have a large number of people who don’t have access to drink clean drinking water. The human body can only survive 3 days without water.  96.5% amount of water can be found in our oceans and 2.3% amount of water is in glaciers. Only 1.2% amount of water is drinkable. But it’s saturated salts and it’s undrinkable. So why can’t we just take all that seawater and filter out the salts and have an unlimited supply of drinkable water?

If you collect a sample of ocean water and take it to the laboratory, you will identify six major ions. They are chloride (Cl⁻), sodium (Na⁺), sulfate (SO2^4−), magnesium (Mg²⁺), calcium (Ca²⁺), and potassium (K⁺). Seawater also contains some other substances and constituents –Boron (B), bromide (Br^-), fluoride (F^-), inorganic carbon, and strontium.

[Magnesium (Mg)- 1%], [Oxygen (O)-86%], [Hydrogen (H)- 11%], [Potassium (K)- 0.04%], [Sodium (Na)-1%], [Sulfur(S)- 0.1%], [Calcium (Ca)- 0.04%], [Bromine (Br)-0.007%], [Carbon (C)- 0.003%], [Chlorine (Cl)- 2%]

If you tried to drink sea water, it will dehydrate you and eventually it kills you.

Normally the saltiness inside our cells is the same as the outside of it. When you drink water, concentration differences take place in water from the outside.  Water from the outside of your cell moves inside to maintain balance. This process is called ISOTONIC STATE.

If you drink too much sea water, saltiness outside of your cell will increase. Your cells force water molecules out in order to maintain the balance. So even if you are already dehydrated drinking seawater causes your cells to release more water. You will lose more liquid than you take in.

What is Desalination?

 A process that takes away mineral components from saline water.

In fact, it is a natural process. When the sun heats the ocean, freshwater evaporates off and falls as rain. This is desalination.

North America and the Middle East countries use ocean water desalination.

There are two types;

1. Thermal desalination

2. Reverse osmosis

 

 

 Thermal desalination -

This is the oldest form of desalination. It’s essentially boiling water and capturing the steam and turning that into freshwater.

Reverse osmosis -

Using a high-pressure pump to increase the pressure on the salt side of the RO and force the water across the semi-permeable RO membrane, leaving almost all (around 95% to 99%) of dissolved salts behind in the reject stream.

Brine

Brine is formed as a byproduct of ocean water desalination. For every 1L of desalinated water produced, we produce 1.5L of brine. Brine is water with a high concentration of salt. Globally we produce 114 B liters of brine per day. We produce more brine than desalinated water.

Cost

It’s very expensive. The energy required to purify seawater is 25 times greater than purifying normal water.

Environmental impacts

It has impacts on the marine environment.

Most of the brine releases back to the ocean.

#facts

What should you do if you are lost on a desert island?

So, there is no freshwater. The way to extract clean water from seawater is Desalination. You have to heat the seawater so that it evaporates and then trap the evaporate water vapor until it cools and it conduces back to liquid water. You can dig a hole to collect water and then use a plastic bag to seal that hole and trap water vapor. 

 

The least we can do is to save water when we can. Close those leaking taps.

Sources;      puretecwater.com         

                   youtube.com                   

Rtr. Ashwin Wijesundara Ranasinghe

(vice president 2020/2021)