Desalination is the process of removing salt from seawater to produce fresh water for human consumption and irrigation. Over 18,000 desalination plants operate globally, including in Pakistan. Karachi faces a severe water shortage as it only receives 450 million gallons per day but needs 1200 million gallons. Desalination is the only solution to Karachi's water crisis. Several desalination plants have been built in Karachi and surrounding areas to produce fresh water and alleviate the water shortage problem.

1. DESALINATION;
• Desalination is the process of removing salt from seawater. By installing a desalination plant,
saline water of the sea is turned into fresh, drinkable water. More than 18,000 desalination
plants operate in 150 countries, including US, China, India, Saudi Arabia, Gulf States, etc
• Feedwater sources may include brackish, seawater, wells, surface (rivers and streams),
wastewater, and industrial feed and process waters.
• Saltwater is desalinated to produce water suitable for human consumption and irrigation.
• Most of the modern interest in desalination is focused on cost-effective provision of fresh
water for human use.
• Due to its energy consumption, desalinating sea water is generally more costly than fresh water
from rivers or groundwater, water recycling and water conservation.

2. DESALINATION IN KARACHI;
• Desalination is the only solution to the Karachi water crisis.
• Karachi needed 1200 million gallon per day(MGDs) but city got only 450 MGDs of water through
pipelines branching from Keenjhar Lake in Thatta district.
• The city received another 20MGDs of water from Hub dam which was originally designed to provide
approximately 100MGDs of water.
• Sometimes the Hub dam does not even provide 20 MGDs of water because of lack of rainfall.
• In such condition, Karachi can only get water either through desalination or by using the recycled
water, For desalination, approximately 1 Megawatt (MW) of power is required to desalinate 1 MGD
water.

3. DESALINATION PLANTS IN KARACHI/PAKISTAN;
• A water desalination plant was recently inaugurated by Pakistan’s Minister for Ports and
Shipping at the port city of Gwadar on 01 Jan, 2018. This is one of the biggest of its kind plant in
Pakistan. This plant (which can hold 5 million gallons of water) will provide 254,000 gallons of
clean potable drinking water per day – at Rs. 0.8 per gallon.
• The desalinate plant can be developed using solar technologies, but desalination water can only
be used for municipal and industrial use, not for drinking purposes on mass scale.
• The seawater treatment plans also pose environmental challenges. The energy requirement is
about 40 percent of the cost. Given the salinity level of our sea, we require 3 KWH to desalinate
1000 litres of water and this water would only be used for municipal and industrial purposes.

4. CONTINUE…
• The task for the installation of the four desalination plants was assigned to the Balochistan Development Authority
(BDA) which had begun work on the project shortly. The construction cost of one plant being installed in Gwadar’s
industrial area was Rs1 billion. It had a capacity of two million gallons of water per day. The other three plants having
capacity of 200,000 gallons of water were installed in Pasni, Jewani and Singhar Housing Scheme with a cost of Rs200
million for each.
• A desalination plant installed in the private sector is working successfully and is selling 100,000 gallons of drinking
water to the public health engineering department daily for the supply of water to the people of Gwadar
• After Gwadar and adjacent areas were hit by a severe water shortage crisis in 2014, authorities had tried to complete
the desalination plant installed in the Gwadar’s industrial area on an emergency basis. Generators were provided and
transmission lines were laid. But, the plant could not achieve its full capacity. It is now producing 300,000 to 400,000
gallons of water per day.

5. REASONS OF SALINIZATION IN KARACHI/PAKISTAN;
Salinization is the increase of salt concentration in soil and is, in most cases, caused by dissolved salts in the
water supply. This supply of water can be caused by flooding of the land by seawater, seepage of seawater or
brackish groundwater through the soil from below.
• Excessive pumping of groundwater and continuous lowering of water-table is likely to result in intrusion of
sea- water into the Malir Basin under natural seepage conditions and under artificially induced conditions
recharge of saline seawater in the coastal aquifer(s) of Karachi.
Due to climate change, sea levels are rising, which further accelerates the process of salinization.
• Reduction of precipitation (infiltration).
• Sea level change.
• Geology (e.g. near-shore karst formations)
• High salt content of the parent material or ground water.
• Illegal pumping.
• Salt-rich irrigation water.