- Email: [email protected]
Desalination of brackish groundwater in Egypt
DESALINATION ELSEVIER
Desalination 152 (2002) 19-26 www.elsevier.comhcate/desal
Desalination of brackish groundwater in Egypt Ahmed R. Allama, Ele-Jan SaaP*, Mohamed A. Dawoud” GSW-TA Project, IO Madina El Monowara Street, Mohandiseen, Cairo, Egypt Tel. +20 (12) 325 67 22; Fax +20 (2) 760 56 21; email: GSW@soj?com.com.eg
Received 28 April 2002; accepted 10 May 2002
Abstract Fresh groundwater resources in Egypt contribute to some 20% of the total potential of water resources in Egypt. The Ministry of Water Resources and Irrigation (MWRI) increasingly recognizes its importance in the overall water resources management. The need for a more comprehensive groundwater management approach has led to the establishment of the Groundwater Sector (GWS) in December 1999. The GWS is now the sole responsible governmental agency for management of all groundwater resources and related water resources. The mandate of the GWS is: formulating and implementing the general policy for developing and managing groundwater and related water resources (flash floods, rainwater harvesting and desalinated water) on the national, regional and sub-regional level. Desalination of brackish groundwater in Egypt has a great potential with respect to the availability of the resource. All major aquifer systems in Egypt contain vast quantities of brackish groundwater. The exploitation of this resource is still limited. With the current low price of brackish water desalination there is a growing interest towards its exploitation. Brackish water desalination plants in Egypt confirm the potential of this solution. Other uses for brackish groundwater that are being considered are agriculture (salt tolerant crops) and fisheries (shrimp farms). The elements of the vision for desalination of brackish groundwater are: environmental sustainability through recycling of water and re-infiltration; public-private partnerships for exploitation, especially in the tourism sector; private sector financing through accepted modalities (BOT, DBO, etc.). With the input of experience from the Netherlands through the GWS project a new program for desalination was started. This program aims to provide the necessary concepts and data on desalination of brackish groundwater in Egypt to allow the GWS to formulate a clear policy in this regard. Keywords: Desalination; Groundwater; Egypt; Public; Private; Privatization
*Corresponding author. Presented at the EuroMed 2002 conference on Desalination Strategies in South Mediterranean Countries: Cooperation between Mediterranean Countries of Europe and the Southern Rim of the Mediterranean. Sponsored by the European Desalination Society and Alexandria University Desalination Studies and TechnoIogv Center, Sharm El Sheikh, Egypt, May 4-6, 2002. 001 I-9164/02/$- See front matter Q 2002 Elsevier Science B.V. All rights reserved PII:SOOll-9164(02)01044-5
20
A. R. Allam
el al. / Desalination
1. Introduction The main challenge facing Egyptian national development is limited water resources. Water is the main factor, which determines the type, size and location of any economic activity. Egypt is a very arid country, where the average annual rainfall seldom exceeds 200 mm along the northern coast. The rainfall declines very rapidly from the coastline to the inland areas, and becomes almost nil south of Cairo. This meager rainfall occurs in the winter in the form of scattered showers, and canuot be depended upon for extensive agricultural production. Thus, reliable availability of irrigation water is a mandatory condition for agricultural development. The main and almost exclusive source of surface water in Egypt is the RiverNile. The 1959 agreement between Egypt and Sudan was based on the average flow of the Nile during the period 1900-1950. The average annual flow at Aswan during that period was 84 billion m3. The average annual evaporation and other losses in Lake Nasser were estimated as 10 billion m3, leaving a net usable annual flow of 74 billion m3. Under the 1959 treaty, 55.5 billion m3 were allocated to Egypt and 15.5 billion m3 to the Sudan. The High Aswan Dam was constructed in 1968 to assure the long-term availability of water for both countries. Its lake has a live storage capacity of 130 billion m3. The annual discharges from the High Dam Lake during the period 1968 to 2000 are 67.6 billion m3. 2. Groundwater
in Egypt
In Egypt groundwater can be classified into two categories. The first comprises groundwater in the Nile Valley and Delta system. The total storage capacity of the Nile Valley aquifer system is about 200 billion m3, with an average salinity of 800 ppm. Another 300 billion m3 is the storage capacity of the Delta aquifer. The current annual rate of groundwater withdrawal from the Valley and Delta aquifers is 6.13 billion m3/y. The second category is the nonrenewable type, which is located in the Western
152 (2002)
19-26
Desert in the Nubian Sandstone Aquifer. Where the groundwater exists in the Western Desert, it is deep seated. Recent studies have indicated that this is not a renewable resource. Use of this fossil water depends on the cost of pumping and potential economic return over a fixed time period. Groundwater is available in a Sinai in number of aquifers of limited potential. Seasonal rainfall replenishes shallow aquifers in the northern coastal areas. The thickness of the aquifers varies between 30 and 150 m with a salinity varying from 2000 ppm up to 9000 ppm. In the northern and central parts of Sinai, groundwater is partially replenished from rainstorms falling and collecting in the valleys. The current annual abstraction is estimated as 89 million m3. Groundwater investigations in South Sinai have identified several shallow and deep reservoirs, which have a limited potential for development but again of local scale. The coastal aquifer system along the North coast and the Red Sea has a limited potential. The fresh water of average salinity (2000 ppm) floats on the saline water body as lenses. The current annual abstraction from that aquifer is 2 million m3. The El Moghra aquifer system, located west of the Cairo-Alexandria Desert Road with an average thickness of 300m is also considered a non-renewable aquifer system. The current abstraction from this system is estimated at 200 million m3/y. Fig. I shows the main hydrogeological aquifer system in Egypt, while Table 1 shows the hydrogeological characteristics ofthe main aquifers. The Fissured Aquifer system, covering more than 50% of the total area of Egypt, is considered one of the poorest aquifers in the country. The limestone aquifer thickness varies from one place to another. The aquifer thickness is about 200 m at El Farafra oasis to 900 m at Siwa. Table 2 summarizes the abstraction distribution from each area within Egypt. 3. Brackish groundwater In view of the hydro geological investigations of the past decades, the GWS is well informed,
.”
-.
_
_
.>
-
-
-.
_
-
.”
-
_
_”
,-
.”
_
_^--._..,
__--_
.----.^
+50
O-50
South Sinai Eastern Desert
-
Flowing
500 -
O-100
Hard rocks
Araba
HelwanWadi
Fissured carbonates
1000-12000
loo
50&900
O-200
W. El Natrun Qattara Depr.
200 Flowing
2000 1500
1000 100-500
Moghra Aquifer
1500-2000 lOOO4000
Flowing
<200
O-30
,__-
1000-2000
100~12000
30004000
O-30 &20 &20 Flowing 20-30
50&700 500-1000 1000-1500 1500-2000 10&300
50-200 200 150-300 200-500 lOck300
Western Desert Kharga Dakhla Bahariya Faratra E. Chveinat Eastern Desert Aish El Malha Sinai Nakhl Ain Mussa
Nubian Sandstone Aquifer
100&6000 600-2500 300-800 20&1000
15 50-70 &30
<5 60-80 4+50
0 50-100 15-30
Med. Coast Qaa Plain Arish
Cl500 -4500 <5000
Coastal Aquifer
ppm
500040,000 500040,000 5000-250,000
o-5 O-5 O-3
O-20 O-20 O-100
Nile Valley South Nile Delta North Nile Delta
Nile Valley and Delta
1O-200 100-500 500-1000
Salinity,
Transmissivity, m/d
Saturated thickness, m
Depth to ground water level, m
Top aquifer, m-msl
Location
Aquifer
Table 1 Hydrogeological characteristics of main aquifers
N
A.R. Allam et al. /Desalination
22
152 (2002) 19-26
Fig. 1 Hydrogeological map of Egypt.
Table 2 Distribution of groundwater abstraction (million m3/y) Nile Valley and Delta
Western Desert
Valley
Delta
Nubiau
Moghra
1932
4195
1000
200
both qualitatively and to some extent quantitatively about brackish water occurrences in the following aquifer systems. 3.1. Coastal aquifers In the coastal aquifer systems, both along the Mediterranean as well as along the Red Sea coast (20,000 km*), the water bearing formations comprise coastal dunes and bars, Wadi deposits, calcarenites and shallow marine sands assigned to the Quaternary and to the late Tertiary. The water is recharged from the local rainfall and the runoff. In Mariut area to the west of Alexandria, the excess water in the land reclamation projects, contribute to the recharge of the brackish water.
Eastern Desert
Coastal Aquifers
Sinai
8
2
89
The salinity of the water is affected by seawater intrusion and is generally in excess of 2000 ppm. In some locations along the Red Sea local reservoirs, mainly of geologic structural origin are found in Tertiary and preTertiary. These are found at Ayoun Musa and EI Qaa in Sinai and also at Shagar, Safaga, Quseir, Ras Peras, and Halayib in the Eastern Desert. The exploitable volume of brackish water and also low saline groundwater is of 2 billion m3. 3.2. Nile aquifers These are located both in the Nile proper as well as in the Delta. They consist essentially of Quaternary alluvial and are reported in the peripheries of the main fresh water bodies in the same
A.R. Allam et al. /Desalination
aquifer. The thickness of the brackish water horizons varies from few to about 100 m. The salinity of the water, both bicarbonate and chloride, is in excess of 1500 ppm. This salinity results from the lateral seepage of saline water from the adjacent aquifer systems (mainly carbonates), from the upward leakage of paleo-ground water from deep-seated aquifers. The volume of exploitable brackish water is estimated as 4 billion m3. 3.3. El Moghra Aquifer This aquifer, dominated by fluvio-marine sands, occupies a wide area located to the west of the Nile Delta. The water-bearing beds belong to an ancient delta of a river dating back to early Miocene times. The thickness of the aquifer varies from a few tens of meters in the eastern side to almost 1000 m in the western side i.e. in the vicinity of the Qattara and Sidi Barrani. The brackish water in that aquifer occupies a wide belt to the west of Wadi El Farigh and Wadi El Natrun and the water changes to saline and hyper saline further to the west. The water in the Moghra aquifer is fossil water, although there are indications of hydraulic continuity with the Delta aquifer. The estimation of the volume of exploitable brackish water in the Moghra aquifer (>3000 ppm)
23
152 (2002) 19-26
has not been made, but it can be in excess of 1 billion m3. Associated with El Moghra aquifer, there is a localized aquifer in the Pliocene beds, known as Wadi El Natrun aquifer. It is generally brackish (salinity >lOOOppm) and is fed mainly by lateral seepage from the Delta aquifer and from upward leakage from the Moghra. 3.4. Nubian Sandstone Aquifer The eastern portion of this regional aquifer occupies an area of about 100,000 km* holds brackish water with salinities varying from 1500 to 3500 ppm. This type of water is reported at Wadi Qena, Wadi EI laqliita, Wadi Umm Hibal, Dahmit and Andendan, etc. in the Eastern Desert as well as in Idfu, Esna, Kom Ombo, Aswan, Kalabsha and Tlishka in the Nile Valley. Similar brackish water and passing into saline water at depths is reported in the same aquifer in Qattara and Siwa area. In the Sinai Peninsula the brackish water dominates the Nubian formations and the reserve estimates are in excess of 100 billion m3. Similar brackish water and low saline water are found in the Eastern Desert along the Red Sea. Areas of interest are Safaga, Quseir, Mersa Alam, Halaib, etc. On the regional level, the estimates of the brackish water in the Nubian Sandstone Aquifer are in excess of 500 billion m3.
Table 3 Exploitable volumes of brackish groundwater Aquifer
Location
Area, km2
Salinity, mg/l TDS
Exploitable volume, billion m3
Coastal aquifers
Coastal dunes Fluviatil of wadis Calcarenites Shallow marine sands
20,000
>2,000
<2
Nile aquifers
Fringes North coast
>1,500
4
El Moghra aquifer
West of Nile Delta
10,000
>3,000
Nubian Sandstone
Eastern Desert Sinai
100,000
1,soo-3,500
Fissured carbonate aquifer
Western Desert Eastern Desert
500,000
>lOO 5
A.R. Allam et al. /Desalination
24
3.5. Fissured carbonate aquifers These occupy an area of about 500,000 km2 and are the least explored in Egypt. The thickness of the carbonate section is in excess of 1000 m, and in various locations brackish water is found. Of such locations reference is made to Siwa, South Qattara, Faratka, North Kharga, Kurkar, (in West Aswan), South of El Fayoum, etc. All these locations are in the Western Desert. In the Eastern Desert, the few locations include Wadi Araba, St. Paul and St. Antonio. In Sinai the locations include the famous springs on the eastern side, Hamma Sina Musa and a good number of wells drilled in the central portion. The estimate of the exploitable brackish water in the fissured carbonates is in the order of 5 billion m3 (further exploration is needed).
4. Desalination
in Egypt
4. I. Current situation Desalination in Egypt started some 20 years ago for (additional) drinking water supply to coastal towns and in the petroleum sector and the energy sector (power stations). Most of the old installations are evaporation plants. In recent years a large number of RO plants and ED plants have become operational in different economic sector (MWRI, 1998): Tourism sector, mainly along the Red Sea Coast, South Sinai and the Northern Coast. Petroleum sector, for production water and for the provision of potable water in remote working locations Industrial sector, mainly applied in the pharmaceutical, textile and fertilizers industry for provision of production water. Public water supply, mainly to remote coastal towns. Some of these installations are complementary to the main potable water system, to cover peak demands in summer and act as a back up supply during the rest of the year. Health sector, small units to provide high quality water to hospitals.
1.52 (2002) 19-26
Due to the developments in desalination techniques and the reduction of the cost price, the application opportunities of desalination for fresh water production have sharply increased and will become even a more competitive option in the future. Desalination has long been confined to situations where no other alternatives were available (coastal towns, islands, remote industrial sites) or where energy was abundantly available (power stations, gas and oil production fields). Today, desalination is becoming a serious option for water production as alternative for traditional surface water treatment and long distance conveyance. This applies for both the drinking water sector and for the industrial sector. The main technologies for desalination are multi-stage flash evaporation (MSF) and reversed osmosis (RO). Reversed osmosis is currently the fastest growing technology and is applied not only for desalination of seawater but also for treatment of brackish water and to produce high quality production water for industrial use and even to treat domestic waste water or drainage water. The increased use of desalination is also notable in Egypt, where the total installed capacity has grown to some 150,000 m3/y (Fig. 2). Most of the plants treat seawater, but a growing number of installations use brackish water as feed water. The capacity ofthe installations is generally small and ranges between 500 and 10,000 m3/d.
1965
1975
1905
Years
Fig. 2. Desalination capacity in Egypt.
1995
2005
A.R. Allam et al. / Desalination 152 (2002) 19-26 4.2. Brackish groundwater desalination
Desalination of brackish groundwater in Egypt has a great potential with respect to the availability of the resource. All major aquifer systems in Egypt contain vast quantities of brackish groundwater. The exploitation of this resource is still limited. There are a number of reasons that explain this: • Desalination has always had the label of being expensive; • Unfamiliarity with the operation of desalination plants for brackish water; • Unfamiliarity with the dynamics of brackish groundwater during exploitation (quality changes) • Occurrence of brackish groundwater is in low demand areas; • Questions with respect to disposal of the brine (the hyper saline effluent). With the current low price of brackish water desalination there is however a growing interest towards its exploitation. One o f the areas o f special interest is the Red Sea coastal area where large quantities o f brackish groundwater are available from different aquifers. Part of this water occurs as springs or can be pumped at shallow depth. An additional advantage o f brackish water along the coast is the option that the brine can be disposed into the sea (taking into account the environmental requirements and conditions).
5. Public private partnerships There is a substantial scope for public/private partnerships (PPP) and private sector financing (PSF) in the field o f desalination. Some of the modalities used for PPP and PSF are Build, Operate, (Own) and Transfer (BO(O)T) or Design, Build and Operate (DBO). The capital expenditures for the installations are usually recovered either through medium term concessions for operation of the plants or a fee for exploitation. The challenge for PPP and PSF in desalination is whether you can:
25
•
Provide water of a specified standard with a unit cost/m 3 which is less than the current unit cost (for example the price of water from the Kuraimat Pipeline); • Provide water of a specified standard with a slightly higher unit cost but with a more sustainable abstraction.
Another selling point for the private sector is the establishment of environmentally friendly resorts using groundwater and recycling wastewater. Many o f the resorts are located in pristine areas where a delicate balance exists between the marine environment and human activities. Tourists may be willing to pay more for their accommodation if they are made aware o f the fact that the resort in which they are staying has made every effort to conserve this balance. Private sector investors in agricultural development have also expressed interest in pursuing the use of brackish groundwater. This has rightfully not been supported by the Groundwater Sector to date due to uncertainties regarding possible negative environmental impacts. Another complicating issue is that little is known of the potential of brackish aquifers and long-term changes in groundwater quality. In many of the resorts, as in Sharm El Sheikh, drinking water is supplied to the hotels and restaurants at a price of LE 8 to LE 12/m 3. The provision of the water is in hands of private international conglomerates that cooperate with Egyptian partners to build the plants and to sell the water. A quick calculation tells us that the above price, which is about 400 to 500% more than the usual price for drinking water in Egypt, easily covers all investment costs, operation and maintenance and depreciation over a period of 10-20 years. The GWS policy aims to stimulate publicprivate partnerships to exploit brackish groundwater for development of remote areas. The GWS however seeks to minimize the environmental damage o f the exploitation and is currently reviewing options for disposal of brine and reuse.
26
A.R. Allam et al, /Desalination
Bibliograpby Abelson, P.H., Desalination of brackish and marine waters, Science, 251 (1991) 1289. Abu-Zeid, KM., Modern Technology Tools for Water Management - Advanced Short Course on Applications of Modem Technology in Water Resources, Cairo, Egypt, 1998. Abu Zeid, M., Some technical and economical consideration on irrigation water pricing, Water Science Magazine, Issue 7, Water Research Center, Cairo, 1990. Abu Zeid, M., Irrigation in Egypt- present and future, Paper presented to 8th Seminar ofthe Regional Commission on Land and Water Use in Cyprus, FAO, Rome, 1985. Allam, M.N., A cost allocation approach for irrigation water in Upper Egypt. Water Res. Manage., 1 1987) 119129. Allam, M.N., Water and Agriculture land in Egypt, Third World Forum, Academic Press, Cairo, Egypt, 2001. Al-Shammiri, M., Safar, M., Multi-effect distillation plants: state of the art, Desalination, 126 (1999) 45-59. Attia, B., Management of Water Resources on Egypt, Short Course, CIHEAM, Cairo, Egypt, 1998. Attia, F.A.R., Management of water systems in Upper Egypt. PhD thesis, Faculty of Engineering, Cairo, University, Cairo, Egypt, 1985. Dreyfus, S., Law, A., The Art and Theory of Dynamic
152 (2002) 19-26
Programming, Academic Press, New York, 1977. Elgafar, A. et al., Egyptian experience in treating and usage of sewage in Agriculture, ch. 17 ,in: Bescod and Petroworth, Sphinx, 1988. Elgamal, Usage of sewage water in irrigation, M.Sc. thesis, Faculty of Agriculture, Ain Shams University, 1984. El Mohamady, E., Impact of treated effluent reuse on the environment with special reference to Egypt, Paper presented to FAO Regional Seminar on Wastewater Reclamation and Reuse, Cairo, Egypt, 1988. Gleick, P.H. Water, war and peace in the Middle East, Environment, 36(3) (1994) 6-15 and 35-42. Hefhy, H., Attia, F., Groundwater in the present and future, Proc. National Conference on The Future of Land Reclamation in Egypt, 1990. Khadr, H.A., Public Expenditure and Agriculture Taxation Case Study of Egypt. Policy Analysis Division, FAO, Rome, 1989. National Water Research Center, Agricultural Usage and Management for Low Quality Water Resources, 1996. World Bank, Egypt, Environmental Issues, World Bank, Washington, DC, 1984. World Bank, Arab Republic of Egypt: Land Reclamation Subsector Review, Report No. 8047-EgT, World Bank, Washington, DC, 1990. World Resources Institute, World Resources 1990-1991, Oxford University Press, New York, 1990, p. 383.
Desalination 152 (2002) 19-26 www.elsevier.comhcate/desal
Desalination of brackish groundwater in Egypt Ahmed R. Allama, Ele-Jan SaaP*, Mohamed A. Dawoud” GSW-TA Project, IO Madina El Monowara Street, Mohandiseen, Cairo, Egypt Tel. +20 (12) 325 67 22; Fax +20 (2) 760 56 21; email: GSW@soj?com.com.eg
Received 28 April 2002; accepted 10 May 2002
Abstract Fresh groundwater resources in Egypt contribute to some 20% of the total potential of water resources in Egypt. The Ministry of Water Resources and Irrigation (MWRI) increasingly recognizes its importance in the overall water resources management. The need for a more comprehensive groundwater management approach has led to the establishment of the Groundwater Sector (GWS) in December 1999. The GWS is now the sole responsible governmental agency for management of all groundwater resources and related water resources. The mandate of the GWS is: formulating and implementing the general policy for developing and managing groundwater and related water resources (flash floods, rainwater harvesting and desalinated water) on the national, regional and sub-regional level. Desalination of brackish groundwater in Egypt has a great potential with respect to the availability of the resource. All major aquifer systems in Egypt contain vast quantities of brackish groundwater. The exploitation of this resource is still limited. With the current low price of brackish water desalination there is a growing interest towards its exploitation. Brackish water desalination plants in Egypt confirm the potential of this solution. Other uses for brackish groundwater that are being considered are agriculture (salt tolerant crops) and fisheries (shrimp farms). The elements of the vision for desalination of brackish groundwater are: environmental sustainability through recycling of water and re-infiltration; public-private partnerships for exploitation, especially in the tourism sector; private sector financing through accepted modalities (BOT, DBO, etc.). With the input of experience from the Netherlands through the GWS project a new program for desalination was started. This program aims to provide the necessary concepts and data on desalination of brackish groundwater in Egypt to allow the GWS to formulate a clear policy in this regard. Keywords: Desalination; Groundwater; Egypt; Public; Private; Privatization
*Corresponding author. Presented at the EuroMed 2002 conference on Desalination Strategies in South Mediterranean Countries: Cooperation between Mediterranean Countries of Europe and the Southern Rim of the Mediterranean. Sponsored by the European Desalination Society and Alexandria University Desalination Studies and TechnoIogv Center, Sharm El Sheikh, Egypt, May 4-6, 2002. 001 I-9164/02/$- See front matter Q 2002 Elsevier Science B.V. All rights reserved PII:SOOll-9164(02)01044-5
20
A. R. Allam
el al. / Desalination
1. Introduction The main challenge facing Egyptian national development is limited water resources. Water is the main factor, which determines the type, size and location of any economic activity. Egypt is a very arid country, where the average annual rainfall seldom exceeds 200 mm along the northern coast. The rainfall declines very rapidly from the coastline to the inland areas, and becomes almost nil south of Cairo. This meager rainfall occurs in the winter in the form of scattered showers, and canuot be depended upon for extensive agricultural production. Thus, reliable availability of irrigation water is a mandatory condition for agricultural development. The main and almost exclusive source of surface water in Egypt is the RiverNile. The 1959 agreement between Egypt and Sudan was based on the average flow of the Nile during the period 1900-1950. The average annual flow at Aswan during that period was 84 billion m3. The average annual evaporation and other losses in Lake Nasser were estimated as 10 billion m3, leaving a net usable annual flow of 74 billion m3. Under the 1959 treaty, 55.5 billion m3 were allocated to Egypt and 15.5 billion m3 to the Sudan. The High Aswan Dam was constructed in 1968 to assure the long-term availability of water for both countries. Its lake has a live storage capacity of 130 billion m3. The annual discharges from the High Dam Lake during the period 1968 to 2000 are 67.6 billion m3. 2. Groundwater
in Egypt
In Egypt groundwater can be classified into two categories. The first comprises groundwater in the Nile Valley and Delta system. The total storage capacity of the Nile Valley aquifer system is about 200 billion m3, with an average salinity of 800 ppm. Another 300 billion m3 is the storage capacity of the Delta aquifer. The current annual rate of groundwater withdrawal from the Valley and Delta aquifers is 6.13 billion m3/y. The second category is the nonrenewable type, which is located in the Western
152 (2002)
19-26
Desert in the Nubian Sandstone Aquifer. Where the groundwater exists in the Western Desert, it is deep seated. Recent studies have indicated that this is not a renewable resource. Use of this fossil water depends on the cost of pumping and potential economic return over a fixed time period. Groundwater is available in a Sinai in number of aquifers of limited potential. Seasonal rainfall replenishes shallow aquifers in the northern coastal areas. The thickness of the aquifers varies between 30 and 150 m with a salinity varying from 2000 ppm up to 9000 ppm. In the northern and central parts of Sinai, groundwater is partially replenished from rainstorms falling and collecting in the valleys. The current annual abstraction is estimated as 89 million m3. Groundwater investigations in South Sinai have identified several shallow and deep reservoirs, which have a limited potential for development but again of local scale. The coastal aquifer system along the North coast and the Red Sea has a limited potential. The fresh water of average salinity (2000 ppm) floats on the saline water body as lenses. The current annual abstraction from that aquifer is 2 million m3. The El Moghra aquifer system, located west of the Cairo-Alexandria Desert Road with an average thickness of 300m is also considered a non-renewable aquifer system. The current abstraction from this system is estimated at 200 million m3/y. Fig. I shows the main hydrogeological aquifer system in Egypt, while Table 1 shows the hydrogeological characteristics ofthe main aquifers. The Fissured Aquifer system, covering more than 50% of the total area of Egypt, is considered one of the poorest aquifers in the country. The limestone aquifer thickness varies from one place to another. The aquifer thickness is about 200 m at El Farafra oasis to 900 m at Siwa. Table 2 summarizes the abstraction distribution from each area within Egypt. 3. Brackish groundwater In view of the hydro geological investigations of the past decades, the GWS is well informed,
.”
-.
_
_
.>
-
-
-.
_
-
.”
-
_
_”
,-
.”
_
_^--._..,
__--_
.----.^
+50
O-50
South Sinai Eastern Desert
-
Flowing
500 -
O-100
Hard rocks
Araba
HelwanWadi
Fissured carbonates
1000-12000
loo
50&900
O-200
W. El Natrun Qattara Depr.
200 Flowing
2000 1500
1000 100-500
Moghra Aquifer
1500-2000 lOOO4000
Flowing
<200
O-30
,__-
1000-2000
100~12000
30004000
O-30 &20 &20 Flowing 20-30
50&700 500-1000 1000-1500 1500-2000 10&300
50-200 200 150-300 200-500 lOck300
Western Desert Kharga Dakhla Bahariya Faratra E. Chveinat Eastern Desert Aish El Malha Sinai Nakhl Ain Mussa
Nubian Sandstone Aquifer
100&6000 600-2500 300-800 20&1000
15 50-70 &30
<5 60-80 4+50
0 50-100 15-30
Med. Coast Qaa Plain Arish
Cl500 -4500 <5000
Coastal Aquifer
ppm
500040,000 500040,000 5000-250,000
o-5 O-5 O-3
O-20 O-20 O-100
Nile Valley South Nile Delta North Nile Delta
Nile Valley and Delta
1O-200 100-500 500-1000
Salinity,
Transmissivity, m/d
Saturated thickness, m
Depth to ground water level, m
Top aquifer, m-msl
Location
Aquifer
Table 1 Hydrogeological characteristics of main aquifers
N
A.R. Allam et al. /Desalination
22
152 (2002) 19-26
Fig. 1 Hydrogeological map of Egypt.
Table 2 Distribution of groundwater abstraction (million m3/y) Nile Valley and Delta
Western Desert
Valley
Delta
Nubiau
Moghra
1932
4195
1000
200
both qualitatively and to some extent quantitatively about brackish water occurrences in the following aquifer systems. 3.1. Coastal aquifers In the coastal aquifer systems, both along the Mediterranean as well as along the Red Sea coast (20,000 km*), the water bearing formations comprise coastal dunes and bars, Wadi deposits, calcarenites and shallow marine sands assigned to the Quaternary and to the late Tertiary. The water is recharged from the local rainfall and the runoff. In Mariut area to the west of Alexandria, the excess water in the land reclamation projects, contribute to the recharge of the brackish water.
Eastern Desert
Coastal Aquifers
Sinai
8
2
89
The salinity of the water is affected by seawater intrusion and is generally in excess of 2000 ppm. In some locations along the Red Sea local reservoirs, mainly of geologic structural origin are found in Tertiary and preTertiary. These are found at Ayoun Musa and EI Qaa in Sinai and also at Shagar, Safaga, Quseir, Ras Peras, and Halayib in the Eastern Desert. The exploitable volume of brackish water and also low saline groundwater is of 2 billion m3. 3.2. Nile aquifers These are located both in the Nile proper as well as in the Delta. They consist essentially of Quaternary alluvial and are reported in the peripheries of the main fresh water bodies in the same
A.R. Allam et al. /Desalination
aquifer. The thickness of the brackish water horizons varies from few to about 100 m. The salinity of the water, both bicarbonate and chloride, is in excess of 1500 ppm. This salinity results from the lateral seepage of saline water from the adjacent aquifer systems (mainly carbonates), from the upward leakage of paleo-ground water from deep-seated aquifers. The volume of exploitable brackish water is estimated as 4 billion m3. 3.3. El Moghra Aquifer This aquifer, dominated by fluvio-marine sands, occupies a wide area located to the west of the Nile Delta. The water-bearing beds belong to an ancient delta of a river dating back to early Miocene times. The thickness of the aquifer varies from a few tens of meters in the eastern side to almost 1000 m in the western side i.e. in the vicinity of the Qattara and Sidi Barrani. The brackish water in that aquifer occupies a wide belt to the west of Wadi El Farigh and Wadi El Natrun and the water changes to saline and hyper saline further to the west. The water in the Moghra aquifer is fossil water, although there are indications of hydraulic continuity with the Delta aquifer. The estimation of the volume of exploitable brackish water in the Moghra aquifer (>3000 ppm)
23
152 (2002) 19-26
has not been made, but it can be in excess of 1 billion m3. Associated with El Moghra aquifer, there is a localized aquifer in the Pliocene beds, known as Wadi El Natrun aquifer. It is generally brackish (salinity >lOOOppm) and is fed mainly by lateral seepage from the Delta aquifer and from upward leakage from the Moghra. 3.4. Nubian Sandstone Aquifer The eastern portion of this regional aquifer occupies an area of about 100,000 km* holds brackish water with salinities varying from 1500 to 3500 ppm. This type of water is reported at Wadi Qena, Wadi EI laqliita, Wadi Umm Hibal, Dahmit and Andendan, etc. in the Eastern Desert as well as in Idfu, Esna, Kom Ombo, Aswan, Kalabsha and Tlishka in the Nile Valley. Similar brackish water and passing into saline water at depths is reported in the same aquifer in Qattara and Siwa area. In the Sinai Peninsula the brackish water dominates the Nubian formations and the reserve estimates are in excess of 100 billion m3. Similar brackish water and low saline water are found in the Eastern Desert along the Red Sea. Areas of interest are Safaga, Quseir, Mersa Alam, Halaib, etc. On the regional level, the estimates of the brackish water in the Nubian Sandstone Aquifer are in excess of 500 billion m3.
Table 3 Exploitable volumes of brackish groundwater Aquifer
Location
Area, km2
Salinity, mg/l TDS
Exploitable volume, billion m3
Coastal aquifers
Coastal dunes Fluviatil of wadis Calcarenites Shallow marine sands
20,000
>2,000
<2
Nile aquifers
Fringes North coast
>1,500
4
El Moghra aquifer
West of Nile Delta
10,000
>3,000
Nubian Sandstone
Eastern Desert Sinai
100,000
1,soo-3,500
Fissured carbonate aquifer
Western Desert Eastern Desert
500,000
>lOO 5
A.R. Allam et al. /Desalination
24
3.5. Fissured carbonate aquifers These occupy an area of about 500,000 km2 and are the least explored in Egypt. The thickness of the carbonate section is in excess of 1000 m, and in various locations brackish water is found. Of such locations reference is made to Siwa, South Qattara, Faratka, North Kharga, Kurkar, (in West Aswan), South of El Fayoum, etc. All these locations are in the Western Desert. In the Eastern Desert, the few locations include Wadi Araba, St. Paul and St. Antonio. In Sinai the locations include the famous springs on the eastern side, Hamma Sina Musa and a good number of wells drilled in the central portion. The estimate of the exploitable brackish water in the fissured carbonates is in the order of 5 billion m3 (further exploration is needed).
4. Desalination
in Egypt
4. I. Current situation Desalination in Egypt started some 20 years ago for (additional) drinking water supply to coastal towns and in the petroleum sector and the energy sector (power stations). Most of the old installations are evaporation plants. In recent years a large number of RO plants and ED plants have become operational in different economic sector (MWRI, 1998): Tourism sector, mainly along the Red Sea Coast, South Sinai and the Northern Coast. Petroleum sector, for production water and for the provision of potable water in remote working locations Industrial sector, mainly applied in the pharmaceutical, textile and fertilizers industry for provision of production water. Public water supply, mainly to remote coastal towns. Some of these installations are complementary to the main potable water system, to cover peak demands in summer and act as a back up supply during the rest of the year. Health sector, small units to provide high quality water to hospitals.
1.52 (2002) 19-26
Due to the developments in desalination techniques and the reduction of the cost price, the application opportunities of desalination for fresh water production have sharply increased and will become even a more competitive option in the future. Desalination has long been confined to situations where no other alternatives were available (coastal towns, islands, remote industrial sites) or where energy was abundantly available (power stations, gas and oil production fields). Today, desalination is becoming a serious option for water production as alternative for traditional surface water treatment and long distance conveyance. This applies for both the drinking water sector and for the industrial sector. The main technologies for desalination are multi-stage flash evaporation (MSF) and reversed osmosis (RO). Reversed osmosis is currently the fastest growing technology and is applied not only for desalination of seawater but also for treatment of brackish water and to produce high quality production water for industrial use and even to treat domestic waste water or drainage water. The increased use of desalination is also notable in Egypt, where the total installed capacity has grown to some 150,000 m3/y (Fig. 2). Most of the plants treat seawater, but a growing number of installations use brackish water as feed water. The capacity ofthe installations is generally small and ranges between 500 and 10,000 m3/d.
1965
1975
1905
Years
Fig. 2. Desalination capacity in Egypt.
1995
2005
A.R. Allam et al. / Desalination 152 (2002) 19-26 4.2. Brackish groundwater desalination
Desalination of brackish groundwater in Egypt has a great potential with respect to the availability of the resource. All major aquifer systems in Egypt contain vast quantities of brackish groundwater. The exploitation of this resource is still limited. There are a number of reasons that explain this: • Desalination has always had the label of being expensive; • Unfamiliarity with the operation of desalination plants for brackish water; • Unfamiliarity with the dynamics of brackish groundwater during exploitation (quality changes) • Occurrence of brackish groundwater is in low demand areas; • Questions with respect to disposal of the brine (the hyper saline effluent). With the current low price of brackish water desalination there is however a growing interest towards its exploitation. One o f the areas o f special interest is the Red Sea coastal area where large quantities o f brackish groundwater are available from different aquifers. Part of this water occurs as springs or can be pumped at shallow depth. An additional advantage o f brackish water along the coast is the option that the brine can be disposed into the sea (taking into account the environmental requirements and conditions).
5. Public private partnerships There is a substantial scope for public/private partnerships (PPP) and private sector financing (PSF) in the field o f desalination. Some of the modalities used for PPP and PSF are Build, Operate, (Own) and Transfer (BO(O)T) or Design, Build and Operate (DBO). The capital expenditures for the installations are usually recovered either through medium term concessions for operation of the plants or a fee for exploitation. The challenge for PPP and PSF in desalination is whether you can:
25
•
Provide water of a specified standard with a unit cost/m 3 which is less than the current unit cost (for example the price of water from the Kuraimat Pipeline); • Provide water of a specified standard with a slightly higher unit cost but with a more sustainable abstraction.
Another selling point for the private sector is the establishment of environmentally friendly resorts using groundwater and recycling wastewater. Many o f the resorts are located in pristine areas where a delicate balance exists between the marine environment and human activities. Tourists may be willing to pay more for their accommodation if they are made aware o f the fact that the resort in which they are staying has made every effort to conserve this balance. Private sector investors in agricultural development have also expressed interest in pursuing the use of brackish groundwater. This has rightfully not been supported by the Groundwater Sector to date due to uncertainties regarding possible negative environmental impacts. Another complicating issue is that little is known of the potential of brackish aquifers and long-term changes in groundwater quality. In many of the resorts, as in Sharm El Sheikh, drinking water is supplied to the hotels and restaurants at a price of LE 8 to LE 12/m 3. The provision of the water is in hands of private international conglomerates that cooperate with Egyptian partners to build the plants and to sell the water. A quick calculation tells us that the above price, which is about 400 to 500% more than the usual price for drinking water in Egypt, easily covers all investment costs, operation and maintenance and depreciation over a period of 10-20 years. The GWS policy aims to stimulate publicprivate partnerships to exploit brackish groundwater for development of remote areas. The GWS however seeks to minimize the environmental damage o f the exploitation and is currently reviewing options for disposal of brine and reuse.
26
A.R. Allam et al, /Desalination
Bibliograpby Abelson, P.H., Desalination of brackish and marine waters, Science, 251 (1991) 1289. Abu-Zeid, KM., Modern Technology Tools for Water Management - Advanced Short Course on Applications of Modem Technology in Water Resources, Cairo, Egypt, 1998. Abu Zeid, M., Some technical and economical consideration on irrigation water pricing, Water Science Magazine, Issue 7, Water Research Center, Cairo, 1990. Abu Zeid, M., Irrigation in Egypt- present and future, Paper presented to 8th Seminar ofthe Regional Commission on Land and Water Use in Cyprus, FAO, Rome, 1985. Allam, M.N., A cost allocation approach for irrigation water in Upper Egypt. Water Res. Manage., 1 1987) 119129. Allam, M.N., Water and Agriculture land in Egypt, Third World Forum, Academic Press, Cairo, Egypt, 2001. Al-Shammiri, M., Safar, M., Multi-effect distillation plants: state of the art, Desalination, 126 (1999) 45-59. Attia, B., Management of Water Resources on Egypt, Short Course, CIHEAM, Cairo, Egypt, 1998. Attia, F.A.R., Management of water systems in Upper Egypt. PhD thesis, Faculty of Engineering, Cairo, University, Cairo, Egypt, 1985. Dreyfus, S., Law, A., The Art and Theory of Dynamic
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Programming, Academic Press, New York, 1977. Elgafar, A. et al., Egyptian experience in treating and usage of sewage in Agriculture, ch. 17 ,in: Bescod and Petroworth, Sphinx, 1988. Elgamal, Usage of sewage water in irrigation, M.Sc. thesis, Faculty of Agriculture, Ain Shams University, 1984. El Mohamady, E., Impact of treated effluent reuse on the environment with special reference to Egypt, Paper presented to FAO Regional Seminar on Wastewater Reclamation and Reuse, Cairo, Egypt, 1988. Gleick, P.H. Water, war and peace in the Middle East, Environment, 36(3) (1994) 6-15 and 35-42. Hefhy, H., Attia, F., Groundwater in the present and future, Proc. National Conference on The Future of Land Reclamation in Egypt, 1990. Khadr, H.A., Public Expenditure and Agriculture Taxation Case Study of Egypt. Policy Analysis Division, FAO, Rome, 1989. National Water Research Center, Agricultural Usage and Management for Low Quality Water Resources, 1996. World Bank, Egypt, Environmental Issues, World Bank, Washington, DC, 1984. World Bank, Arab Republic of Egypt: Land Reclamation Subsector Review, Report No. 8047-EgT, World Bank, Washington, DC, 1990. World Resources Institute, World Resources 1990-1991, Oxford University Press, New York, 1990, p. 383.