Brackish water (less commonly brack water) is salt water and fresh water mixed together. It is saltier than fresh water, but not as salty as seawater. It may result from mixing of seawater with fresh water.
Scarcity of fresh water has serious implications. It can slow or stop economic expansion, reduce agricultural output, hamper food independence, and degrade public health and quality of life.
Water, water, every where, Nor any drop to drink. —Samuel Taylor Coleridge, The Rime of the Ancient Mariner, part II, stanza 9
MMWD stands for ‘Marin Municipal Water District”
Obtaining reliable fresh
water supplies from
challenging water sources.
The process of
removing dissolved salts from
water, thus producing fresh
water from seawater or
71% of the Earth’s surface
is covered by water.
97.5% of that water is
Only 1% is available for
80 countries suffered from
water scarcity by the mid-
Agriculture and food
Quality of life
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 Mariner
Water, water, everywhere
And all the boards did shrink
Water, water, everywhere
Nor any drop to drink
2 gallons of seawater = 1
gallon of high quality
Pre-treatment and RO
including mercury and
other contaminants in
MMWD will use “dual
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
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
Thermal desalination is a method of cleaning
water that can occur through many different
In this process we heat the water solution and
gathers the pure water when the vapors cools and
o Desalinated water is an important contributor to alleviate
o Today’s world contracted capacity of desalinated plants is
80.2 million m3/day and commissioned capacity 74.6
o 632 new plants were added last year (mid 2011 to August
2012) in the world
Total Installed Desalination Capacity by Region,
Desalination in Middle East
4.4% of the world’s population inhabit the Middle
it only receives 1.1% of the global renewable water
70% of the world’s desalination plants are located in
the Middle East
Saudi Arabia alone is producing 20% of the world’s
”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):
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 SaindakCopperMinesin Balochistan.
It uses the brackish water Reverse Osmosis (BWRO) process.
Another desalination plant was installed in 1995 and commissioned in 1996 at the HUBCOpower
stationoutside 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.