Environmental Science & Engineering - www.esemag.com - March 2004
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Water treatment plants are vital to Baghdad’s restoration
By Ghassan Ghali, R.V. Anderson Associates Limited
As reconstruction of Iraq begins, water treatment
will be one of the most important projects. All
water treatment plants in Iraq are on the Tigris and
Euphrates rivers and their tributaries. The city of
Baghdad was built in 763 A.D., in the central part of Iraq on
the Tigris River, and it is now 30 x 30 km in area with a
population of more than 5 million.
All water treatment plants in Baghdad draw their water
from the Tigris River and the city is now served by several
water treatment plants built during the 20th century. During
the 1970s a 455 MLD (100 MGD) water treatment plant
and transmission pipelines were built to serve the Rasafa
(East Bank of Baghdad). During the 1980s two water treatment
plants of 110 MLD (25 MGD) each were built in
Karkh (the west bank of Baghdad) in addition to a large
scale development in the water supply system.
The large scale development in water services started in
1980. The Baghdad Water Authority hired Binnie and
Partners (British consultants) to prepare for a 1365 MLD
(300 MGD) Karkh Water Supply Scheme and an integrated
study for the development of water supply in Baghdad.
Work started on both projects immediately. The integrated
study also included a 1820 MLD (400 MGD) Rasafa Water
Supply Scheme, similar to the scheme in Karkh, and a large
number of ground storage tanks to meet the increasing
demand. Tunnels across the Tigris River connect both
schemes into one system.
In late 1980, the Karkh Water Supply scheme was
awarded to a design-build consortium of the Iraqi state construction
company and Continental Construction Ltd
(India) with W.S. Atkins (UK) for construction design and
project coordination; Paterson Candy International Ltd. for
treatment process and related mechanical, electrical, control
and telemetry works; Hawker Siddeley Power
Engineering for stand-by power generation and power distribution;
W. H. Allen for the pumping stations; and Kubota
(Japan) for the supply of the ductile iron pipes. The total
cost of the scheme was 1.4 billion (US). Construction
started in May 1981 and was commissioned in stages from
July 1985 until 1990.
The Karkh Water Supply Scheme comprises a river
intake with a low lift pumping station on the Tigris River
incorporating vertical wet well pumps of 9500 m3/hr and
2300 m3/hr, and three 1 km long raw water pipes 1.8 m in
diameter with open top surge concrete towers. The intake
and the treatment works are located 40 km to the north of
Baghdad City to avoid the increasing levels of salinity due
to the discharges from irrigation drains.
The treatment works are arranged in three identical
streams, each with a capacity of 100 MGD (455 MLD).
Each stream comprises eight horizontal flow pre-settlement
tanks to remove the majority of suspended solids that
reaches up to 30,000 mg/L; they are equipped with chain
and flight scrapers followed by six PCI Centrifloc circular
clarifiers, each being 52 m in diameter and 12 m deep with
mechanical vertical flocculators and center-drive scraper.
Clarified water passes to the filter block of 20 filters in
each stream. The filters are 15 m x 12 m PCI K-type rapid
gravity filters and the media is 0.85-1.7 mm sand for a filtration rate of 7.9 m/hr. The filtered
water passes to the three treated water
reservoirs, each with a capacity of 30
ML. The treated water pumping station
draws from the three reservoirs and
pumps it to the transmission pipeline
using eight vertical dry well split case
pumps with 2,300 kW motors each
delivering 50 MGD (228 MLD).
The chemical house contains the
alum, polyelectrolyte and lime storage,
preparation and dosing system. A separate
building is used for the storage
and dosing of chlorine. The total power
needed for the treatment plant is 32
MW and the standby power generating
capacity is 16 MW provided by two 8
MW gas turbines. The administration
building houses the offices, laboratory,
control room and conference hall.
Water is then conveyed from the
treated water pumping station to the
Karkh North Reservoir through twin
2.3 m and 2.1 m diameter ductile iron
pipes each 40 km long. The pipe line is
buried, with the majority of piping
installed by the open cut method to
depths ranging from 4 to 14 metres.
Railway and highway crossings were
constructed using the thrust boring
method without interrupting the services.
The Karkh North Reservoir is 215
ML in capacity with four other reservoirs
with a total storage capacity of
530 ML connected to the main reservoir
by 65 km of transfer pipelines
including a river crossing to transfer
455 MLD (100 MGD) to the Rasafa.
Each reservoir site is equipped with a
distribution pumping station, stand by
generators and re-chlorination facilities.
The project also included 200 km
of main distribution network of ductile
iron pipes ranging between 350 mm
and 1600 mm diameter.
Major quantities for the project
were as follows:
The 1365 MLD (300 MGD) Karkh
Water Supply Scheme served the people
of Karkh with 910 MLD (200
MGD) of drinking water and 455
MLD (100 MGD) was transferred to
the Rasafa across the Tigris River to
cover the delay in construction of the
1820 MLD (400 MGD) Rasafa Water
Supply Scheme that was scheduled to
be constructed in the late 1980s and to
be commissioned in 1992. Wars and
budget shortage delayed the construction
of the Rasafa Water Supply
Scheme.
Both sides of Baghdad are in need
of more treated water. Baghdad Water
Authority is now willing to move forward
with the development of the Rasafa project in two phases of 910
MLD (200 MGD) each and recently
issued an invitation to international
consultants to submit their bids for the
planning and engineering of the project.
During the Oil for Food Program
(1996 – 2003), work on water treatment
plants and water supply systems
in Iraq was limited to the import of
spare parts, equipment to replace old
equipment in existing plants, containerized
water treatment units of
50m3/hr to 200 m3/hr capacity and consumables
such as chlorine and alum.
Currently, there are 250 large water
treatment plants in Iraq that require
rehabilitation or
upgrading, and a
large number of
new water treatment
facilities
need to be built
to respond to the
demand for
water quality.
Contact Ghassan Ghali at e-mail: gghali@rvanderson.com.
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