Water Desalination

Obtaining reliable fresh water supplies from challenging water sources.

“Composer”

Adnan Aslam B.sc Mechanical Engineering HITEC university Taxila, Islamabad Pakistan

What Is

Desalination…???

Desalination:

The process of

removing dissolved salts from

water, thus producing fresh

water from seawater or

brackish water.  

71% of the Earth’s surface is covered by water.

97.5% of that water is oceans.

Only 1% is available for drinking.

80 countries suffered from water scarcity by the mid-1990s.

Why Desalination…???

Economic expansion

Agriculture and food

Public health

Quality of life

Fresh Water Needs..!!!!!

Can we drink salt water..??

Small quantities are not harmful, but it is counterproductive (it just makes you more thirsty!)

Eventually, it can be dangerous, ultimately producing fatal seizures, heart arrhythmias and kidney failure

The Rime of the Ancient MarinerWater, water, everywhere

And all the boards did shrinkWater, water, everywhere

Nor any drop to drink

Desalination By Reverse Osmosis

2 gallons of seawater = 1 gallon of high quality drinking water

Pre-treatment and RO removes contaminants, including mercury and other contaminants in the Bay

MMWD will use “dual pass” RO

Flow at the Membrane

Forward Osmosis

Forward osmosis utilizes the osmotic process , a substance moving from an area of low concentration to an area of high concentration.

It generally requires about half of the cost of reverse osmosis.

Electro dialysis

Electro dialysis reversal utilizes a membrane, like that in reverse osmosis.

It sends an electric charge through the solution to draw metal ions to the positive plate on one side, and other ions (like salt) to the negative plate on the other

Thermal DesalinationThermal desalination is a method of

cleaning water that can occur through many different processes.

In this process we heat the water solution and gathers the pure water when the vapors cools and condensation occurs.

Desalination Plants around the World

o Desalinated water is an important contributor to alleviate water shortage.

o Today’s world contracted capacity of desalinated plants is 80.2 million m3/day and commissioned

capacity 74.6 million m3/day.o 632 new plants were added last year (mid 2011

to August 2012) in the world

Total Installed Desalination Capacity by Region, Worldwide

Middle East 53.40%

Central America, South America, & Australia; 2.80%

Africa6.20%Asia; 10.60%

Europe10.10%

North America; 17.00%

Desalination in Middle East4.4% of the world’s population inhabit the

Middle East(AQUASTAT 2005)it only receives 1.1% of the global renewable

water resources. 70% of the world’s desalination plants are

located in the  Middle East Saudi Arabia alone is producing 20% of the

world’s desalinated water.

DESALINATION IN PAKISTAN

WHEN &WHERE?

”DHA Desalination and Power Plant”It is the first project of its kind in Pakistan which desalinates water from the Arabian Sea for human consumption as well as provides Electrical Power to the KESC grid.

Manora Water Desalination plant(Karachi):• Capacity:

200,000 to 250,000 gallons of water per day for Navy.

The Pakistan Water and Power Development Authority (WAPDA) has installed 12 desalination plants along Manchar lake for providing potable water to the populace residing in the areas adjacent to the lake.

The water treatment plants have cumulative design capacity of 15000 liters per hour. Over 4,000 families of fishermen folk (about 32,000 to 40,000 persons) are being facilitated with high quality potable water.

A desalination plant was installed in 1987 in Saindak Copper Mines in Balochistan. It uses the brackish water Reverse Osmosis (BWRO) process.

Another desalination plant was installed in 1995 and commissioned in 1996 at the HUBCO power station outside Karachi. This plant uses Reheat type Multi-effect distillation (MED) desalination.

KANUPP near Karachi operates a Sea Water Reverse Osmosis (SWRO) desalination plant to meet its operating requirements.

THANK YOU………….