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Desalination Technologies: Hellenic Experience

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  • National Foundation for Agricultural Research, Institute of Crete

Abstract and Figures

Beyond doubt, desalination is growing rapidly worldwide. However, there are still obstacles to its wider implementation and acceptance such as: (a) high costs and energy use for fresh water production; (b) environmental impacts from concentrate disposal; (c) a complex, convoluted and time-consuming project permitting process; and (d) limited public understanding of the role, importance, benefits and environmental challenges of desalination. In this paper, a short review of desalination in Greece is being made. Data on the cost of desalination shows a decrease in the future and the potential of water desalination in Greece. The paper summarizes the current status in southeastern Greece (e. g., Aegean islands and Crete), and investigates the possibility of production of desalinated water from brackish water.
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Water 2014, 6, 1134-1150; doi:10.3390/w6041134
water
ISSN 2073-4441
www.mdpi.com/journal/water
Review
Desalination Technologies: Hellenic Experience
Konstantinos Zotalis 1,*, Emmanuel G. Dialynas 2, Nikolaos Mamassis 1 and Andreas N. Angelakis 3,4
1 Department of Water Resources and Environmental Engineering,
National Technical University of Athens (NTUA), Heroon Polytechniou 9, Zografou,
Athens 15780, Greece; E-Mail: nikos@itia.ntua.gr
2 Dialynas SA Environmental Technology, P.O. BOX 4 Alikarnasos, Iraklion, Crete 71601, Greece;
E-Mail: md@dialynas.com
3 National Agricultural Research Foundation (NAGREF), Iraklion Institute, Iraklion,
Crete 71203, Greece; E-Mail: info@a-angelakis.gr
4 Hellenic Union of Municipal Enterprises for Water Supply and Sewerage (EDEYA), 37-43 Papakuriazi,
Larissa 41222, Greece
* Author to whom correspondence should be addressed; E-Mail: kzotalis@gmail.com;
Tel.: +30-69-3706-5768.
Received: 18 February 2014; in revised form: 6 April 2014 / Accepted: 17 April 2014 /
Published: 30 April 2014
Abstract: Beyond doubt, desalination is growing rapidly worldwide. However, there are
still obstacles to its wider implementation and acceptance such as: (a) high costs and
energy use for fresh water production; (b) environmental impacts from concentrate disposal;
(c) a complex, convoluted and time-consuming project permitting process; and (d) limited
public understanding of the role, importance, benefits and environmental challenges of
desalination. In this paper, a short review of desalination in Greece is being made. Data on
the cost of desalination shows a decrease in the future and the potential of water
desalination in Greece. The paper summarizes the current status in southeastern Greece
(e.g., Aegean islands and Crete), and investigates the possibility of production of
desalinated water from brackish water.
Keywords: brackish water; cost of desalination; desalination worldwide; desalination plants
in Greece
OPEN ACCESS
Water 2014, 6 1135
1. Introduction
Ever since desalination was originally invented in antiquity, different technologies have been
developed. Back in the 4th century BC, Aristotle, the Hellenic philosopher, described a desalination
technique by which non-potable water evaporated and finally condensed into potable liquid.
Likewise, Alexander of Aphrodisias in the 200 AD described a technique used by sailors, as follows:
seawater was boiled to produce steam, and that steam was then absorbed by sponges, thereby resulting
in potable water [1]. Since then, the technology of seawater desalination for the production of potable
water evolved rapidly and has become quite popular [2].
The most reliable desalination processes that can currently be exploited at the commercial scale can
be divided in two main categories:
(a) thermal (or distillation) processes like multi-stage flash distillation (MSF), multi-effect
distillation (MED), thermal vapor compression (TVC), and mechanical vapor compression
(MVC) processes; and
(b) membrane processes: reverse osmosis (RO) and electrodialysis (ED) processes. ED is mostly
used for brackish water installations, while RO can be used for both, brackish and seawater [3].
Over the last few years, a large number of desalination plants began to operate globally.
Moreover, the production cost of desalinated water has been considerably decreased and is expected to
decrease even further [4,5]. This is mostly due to the recent improvements in membrane technology,
but also due to the increase of the energy conversion coefficiency for desalination processes [6].
In this paper, a short review of water desalination is provided before cost data are examined and
processed. This paper focuses on water desalination processes and projects in Greece.
2. Desalination is Growing around the World
Desalination is growing so fast globally that it is more than certain that it will play a significant role
in water supply in the years to come. Desalination is growing particularly in parts of the world where
water availability is low. Annual desalination capacity seems to increase rapidly as years go by.
A sharp increase in the number of desalination projects to supply water is indicated. This rose
from 326 m3/d in 1945 to over 5,000,000 m3/d in 1980 and to more than 35,000,000 m3/d in 2004 [7].
In 2008, the total daily capacity was 52,333,950 m3/d, from some 14,000 plants in operation globally [8].
In 2011, the total capacity was about 67,000,000 m3/d, while in 2012 it was estimated at about
79,000,000 m3/d from some 16,000 plants worldwide [9].
The Gulf Region (Middle East) has the biggest number of desalination plants in the world,
followed by the Mediterranean, the Americas, and Asia [10]. The percentages of desalination plants
for each geographical area are shown in Figure 1.
The global capacity of desalination plants, including renewable desalination, is expected to grow at
an annual rate of more than 9% between 2010 and 2016. The market is set to grow in both developed
and emerging countries such as the United States, China, Saudi Arabia (SA) and the United Arab
Emirates (UAE), as shown in Figure 2. A very significant potential also exists in rural and remote areas,
as well as in islands (Figure 2, rest of world (ROW)), where grid electricity or fossil fuels to generate
energy may not be available at affordable costs. About 54% of the global growth is expected to occur
Water 2014, 6 1136
in the Middle East and North Africa (MENA) region [11], where the 21 million m3/d of desalinated
water in 2007 is expected to reach 110 million m3/d by 2030, of which 70% is in SA, the UAE,
Kuwait, Algeria and Libya [11].
Figure 1. World desalination plants per geographical area (%). Adapted from [10].
Figure 2. Global installed desalination capacity, 2010–2016. Adapted from [11].
The majority of the largest desalination plants (in operation or under construction) use seawater and
are located in the Middle East. The biggest desalination plant is the Ras Al-Khair in the city of Ras
Al-Khair (also called Ras Al-Zour or Ras Azzour) SA, which uses both membrane and thermal
technology with a capacity over 1,000,000 m3/d, in operation since 2013. The Ras Al-Khair plant
supplies Maaden factories with 25,000 m3 of desalinated water and 1350 MW of electricity. It also
supplies with water the capital city of Riyadh and several central cities with a total need of
900,000 m3/d [12,13]. Another example is the 880,000 m3/d MSF Shuaiba 3 desalination plant that is
located along the east coast of SA and supplies with potable water the cities of Jeddah, Makkah, and Taif.
SA also hosts the Ras Al-Zour unit, producing 800,000 m3/d of water [14]. Table 1 shows some of the
biggest desalination plants in the world.
Water 2014, 6 1137
Table 1. The biggest desalination plants around the world. SA: Saudi Arabia; and UAE:
United Arab Emirates. Adapted from [12,13,15].
Location Capacity (m3/d) Feedwater Operation year
Ras Al-Khair, SA 1,025,000 N/A 2013
Shuaiba, SA 880,000 Seawater 2007
Ras Al-Khair, SA 800,000 Seawater 2007
Al Jubail, SA 730,000 Seawater 2007
Jebel Ali, United Arabic Emirates 600,000 Seawater 2011
Al-Zour North, Kuwait 567,000 Seawater 2007
As far as the membrane technologies are concerned, especially the RO desalination technology
(one of the most renowned), there are big plants around the world with great potential in energy saving
and reasonable production cost (Table 2) [16]. The largest membrane desalination plant in the world is
the Victoria Desalination Plant in Melbourne, Australia with a capacity 444,000 m3/d, in operation
since 2012. However, larger units will soon operate, like the Magtaa plant in Algeria and the Soreq
plant in Israel, with capacities of 500,000 m3/d and 510,000 m3/d, respectively [13].
Table 2. Major reverse osmosis (RO) desalination plants in the world. Adapted from [13,16].
Location City, Country Capacity (m3/d)
Soreq desalination plant Rishon Letzion, Israel 510,000
Magtaa desalination plant Oran, Algeria 500,000
Victoria desalination plant Melbourne, Australia 444,000
Point Lisas desalination plant Point Lisas, Trinidad 109,019
Tampa Bay desalination plant Tampa, FL, USA 94,635
3. Production Cost of Desalinated Water
The overall cost of desalination can be divided into investment cost and maintenance-operation
cost. Investment cost involves land, edifices and equipment, as well as transportation cost, insurance,
construction, legal fees and unforeseen costs. Maintenance and operation cost is divided in energy cost,
maintenance, repairs, personnel/staff, spare parts, and reconstruction when required. Energy cost is the
higher contributor to operation cost and thus to the overall cost. In many cases, energy cost can reach
almost the 60% of the operation and maintenance cost. A comparison of the total cost of the RO and
MSF technologies is given in Table 3 [17].
Table 3. Cost percentage in conventional RO and multi-stage flash distillation (MSF) of
the same capacity in Lybia. Adapted from [17].
Desalination
technology
Investment
cost (%)
Energy
cost (%)
Maintenance &
repair cost (%)
Membrane
replacement cost (%)
Personnel
cost (%)
Chemicals
cost (%)
RO (membrane) 31 26 14 13 9 7
MSF (thermal) 42 41 8 0 7 2
Cost evaluation for desalination is a difficult process as data are influenced by different factors such
as energy cost, materials and labor. Those factors differ significantly from place to place.
Water 2014, 6 1138
Moreover, cost is influenced by elements like desalination technology, total dissolved solids (TDS)
concentration of the raw water used to feed the plant, and other economic parameters that related to
local conditions [18]. In conclusion, desalination cost is significantly decreasing when brackish water
is used instead of seawater and when the capacity of the plant is increased (Table 4).
Table 4. Desalinated water production cost from seawater and brackish water.
Capacity (m3/d) Cost (€/m3)
Sea water Brackish water
3,800 0.97 0.50
7,600 0.70 0.27
19,000 0.54 0.21
38,000 0.50 0.17
57,000 0.49 0.15
Membrane desalination technologies such as RO are known for their lower energy demands
compared to thermal technologies which can be further reduced using energy recovery systems.
Such limited energy demands have direct effect on the cost of the produced desalinated water,
which in most cases is lower than the cost of water produced by thermal technologies. The RO cost per
feeding water and capacity is shown in Table 5, compared to the cost related to the most common
thermal desalination technologies.
Table 5. RO desalination production cost compared to thermal desalination technologies cost,
per feeding water and production capacity. MED: multi-effect distillation; and VC: vapor
compression. Adapted from [19].
Feedwater Plant capacity (m3/d) Cost (€/m3)
Brackish water RO
<20 4.50–10.32
20–1,200 0.62–1.06
40,000–46,000 0.21–0.43
Seawater RO
<100 1.20–15.00
250–1,000 1.00–3.14
1,000–4,800 0.56–1.38
15,000–60,000 0.38–1.30
100,000–320,000 0.36–0.53
MSF
<100 2.00–8.00
12,000–55,000 0.76–1.20
>91,000 0.42–0.81
MED 23,000–528,000 0.42–1.40
VC 1,000–1,200 1.61–2.13
Hybrid desalination systems, which are used to combine desalination technologies, are suitable for
big installations in order to accomplish scale economies that reduce the production cost. In such plants,
membrane technologies can be combined with thermal technologies and vice versa. To give an example,
in a plant where the brine flow of RO is the feed flow of membrane distillation, the cost is 0.94 €/m3.
Had the system used only RO, the respective cost would be 0.94 €/m3, whereas the same system
Water 2014, 6 1139
operating under membrane distillation would have a production cost of 0.99 €/m3. In other words,
when technologies are combined the double quantity of water is produced at the same cost or less
compared with the alternatives. To give another example, a MSF used in a desalination plant of
528,000 m3/d, produces water at a 0.32 €/m3, whereas when it is combined with RO, its cost is reduced
by 15% [18]. It should be noted that the water production cost of a desalination plant that uses
renewable energy is estimated to be higher than one that uses conventional energy [20]. An example of
the cost per feeding water and energy source used is shown in Table 6.
Table 6. Cost of desalinated water production per feeding water and energy source used.
Adapted from [19].
Feedwater source Energy source Cost (€/m3)
Brackish water
Conventional energy 0.21–1.06
Photovoltaic panels energy 4.50–10.32
Geothermal energy 2.00
Seawater
Conventional energy 0.35–2.70
Wind power 1.00–5.00
Photovoltaic panels energy 3.14–9.00
A decreasing attitude is observed to the cost of desalination for production of potable water,
compared with other technologies. Improvement on membrane technology will be a catalyst in cost
reduction [21]. In Greece and other Mediterranean areas there have been several comparisons between
desalinated water production and conventionally extracted water (e.g., dams and groundwater wells).
However, in such comparisons, the rapid improvement of the RO membrane technology should be
considered. In the near future it is expected that desalinated water cost (especially coming from
brackish water) will be less than any other conventional technologies. It is estimated that desalination
cost will be lowered 4% to 5% per year due to the continuous improvement of membrane technology.
Some examples of desalinated water production cost in different regions worldwide are presented:
(a) In Malta, where 70% of the total water consumption comes from desalination, cost varies
between 0.30 €/m3 and 0.45 €/m3.
(b) In Cyprus, the country with a high density of dams worldwide, the last decade potable water
supply was reinforced by three desalination plants. The total cost at the two plants at Larnaca
varies today from 0.45 €/m3 to 0.54 €/m3.
(c) In Israel, the cost of water production in the Ashkelon plant is around 0.50 €/m3. This quantity
consists of desalinated seawater (48%), desalinated brackish (45%), and recycled wastewater (7%).
The total cost for desalination at the five plants ranged from 0.61 €/m3 to 0.94 €/m3. Increased cost
is due to: (i) the technology chosen (multiple stage evaporation) for the energy consumed;
and (ii) very high TDS concentrations (47,000–50,000 mg/L) of seawater in the Gulf.
(d) In East Australia, in areas with very low water availability (Perth), water supply was based on
desalination for the past 10 years. Total cost was as low 0.33–0.42 €/m3.
(e) In Greece, and especially in touristic areas, there are numerous RO installations. Today, the average
water production cost from seawater for such technology is 0.60–0.70 €/m3. The production
cost in case brackish water is used ranges from 0.3 €/m3 to 0.4 €/m3, depending on the feed
Water 2014, 6 1140
water TDS concentration and the condition of operation and management. On the other hand,
for the RO desalination plant on the island of Milos (with capacity 3360 m3/d and energy
produced from wind turbines), the cost is 1.80 €/m3 [22], whereas in the geothermal MED plant
on the same island, the cost is less than 1 €/m3 [23].
(f) In California, USA, there are over 20 desalination plants operating or under construction that
by 2015 will reach 2,600,000 m3/d, a quantity that covers 15% of the total water needs [9].
One of these plants (Carlsbad), with a capacity of 190,000 m3/d, is called a “Green desalination
plant” as it has environmentally friendly installations, total energy reclamation as well as the
respective minimization of greenhouse gasses. The plant was constructed as a build-own-transfer
(BOT) project and is the biggest in the US, producing 8% of the water needs in the region of
San Diego. Water production cost is estimated at 0.50 €/m3.
(g) In general, the cost of recently constructed RO plants (e.g., in Tampa Bay USA in 2003 and in
Singapore in 2005) has been reduced up to 1/3 in comparison with that of the plants
constructed 13–18 years ago (e.g., in Bahamas in 1995, in Dekelia, Cyprus in 1997, and in
Limassol, Cyprus in 2001) (Figure 3). Such a decrease is not only attributed to the rapid
evolution of desalination technology during recent years but also to the cost reduction due to
the increased size of those plants. It is difficult to quantify the effect that these parameters have,
since they seem to act simultaneously [24].
Figure 3. Cost of desalination plants that were installed between 1995 and 2005.
Adapted from [24].
4. Desalination Environmental Impacts
The desalination process has relatively low environmental impact. However, it is reported that
the discharge of brine into the sea may erode the seashore [25] or harm the aquatic life [26].
Moreover, to avoid unregulated development of coastal areas, desalination activity should be included
in the regional development projects [27].
The main environmental impact concerns are land use, brine disposal, and energy consumption.
Land use issues emerge from the fact that seawater desalination plants are situated close to sites with
Water 2014, 6 1141
particularly sensitive environmental habitats and many social, economic, ecological, and recreational
functions. The search for an appropriate plant location has to be carried out with great caution in order
to minimize adverse impacts [28]. Furthermore, desalination processes produce a particularly high
salinity flow (brine) and its disposal directly to the sea may also harm the environment. Potential
environmental impacts should be minimized by refraining from discharging brine directly into the sea.
Finally, as far as energy consumption is concerned, despite the great achievements in this field,
desalination processes like RO are still quite energy-intensive. Since most of the energy is taken from
fossil sources, the CO2 emissions are an issue that cannot be ignored. However, the use of modern
processes and alternative energy sources can reduce the emissions of CO2 and other air pollutants [29].
5. Water Scarcity in Greece
In Greece, and particularly in several southeastern regions, there is a very low water availability,
which is exacerbated by the high water demand for tourism and irrigation in summertime. Therefore,
the integration of desalinated water, treated wastewater and other marginal waters into water resources
and the management of master plants are of paramount importance to meet future water demands [30].
The problem seems to be more evident in the Aegean Islands (particularly the Dodecanese and
Cyclades), Thessaly in Central Greece, eastern Continental Greece (Sterea Greece), eastern Crete and
the southeastern Peloponnese (Figure 4). More specifically, in central Greece (Thessaly and Sterea
Greece), there is a high water demand for agricultural irrigation [31], while on the islands the problem
is mainly attributed to the increased demand in potable water during the summertime [32]. Both the
population density of the Region of Crete (Prefectures of Chania, Rethymno, Iraklio and Lasithi)
and the Regions of North and South Aegean (Prefectures of Lesvos, Chios, Samos, Dodecanese and
Cyclades) are below the population density of Greece. Both regions receive large numbers of visitors
during the summer [33]. Nonetheless, that high water demand is also attributed to over-exploitation
of groundwater aquifers, as well as to groundwater contamination, including seawater intrusion in
coastal areas. In addition, the small size of the islands and their geography does not allow other
possible cost-effective technologies to increase water availability [31].
The aforementioned regions are located in the southeastern part of Europe. Their climate is
typically Mediterranean: hot and dry. Their relatively long distance from the mainland adds to their
economic woes compared to similar parts of Europe [34]. Due to their geographical isolation, these areas
are equipped with autonomous, yet limited conventional power grids. However, there is an abundance
in renewable energy sources such as aeolic and solar power, as well as geothermal and wave power
(Figure 5) [35].
Currently, the main way for meeting deficient water balance of the “semi-arid” islands is water
transportation whose cost varies from 4.91 €/m3 to 8.32 €/m3 [36], and has a great environmental
burden in terms of ship emissions. Moreover, the water transported is in most cases not potable,
therefore, an economic and environmental analysis should also take into consideration the impacts of
increased use of bottled water. Other ways of meeting the water deficiency needs are the exploitation
of ground water, dams, and rainwater collection.
Water 2014, 6 1142
Figure 4. Deficit and/or surplus of potable water per water district in Greece [31]. With
permission of Stefopoulou et al. (2008) [31].
Figure 5. Renewable energy sources in Cyclades and Dodecanese. With permission of
Manolakos (2012) [35].
Water 2014, 6 1143
Last but not least, there are also a few desalination plants, especially in southeastern water supply
and sewage municipalities or where big hotels are located. Many of these desalination plants use the
RO technology. Apart from the state-owned desalination plants, there are many private plants in
operation owned by hotels. A significant number of desalination plants is currently under construction
or under planning.
6. Desalination Status in Greece
According to the 2011 IDA Worldwide Desalting Plants Inventory in Greece, there are currently
157 operating desalination plants, with a total capacity of 109,115 m3/d, while another 35 are expected
to soon be operational, with a total capacity of 40,135 m3/d. Moreover, in 2011, five more desalination
plants were under construction, with a capacity reaching 32,800 m3/d [37].
As for the feed water, 56% is seawater, while 41% is brackish water (Figure 6a). Regarding the use
of the produced desalinated water, 48.08% is to supply the municipalities, 31.07% goes to the industry,
15.94% covers touristic demands, and 4.24% and 0.16% are directed to power production and water
supply of military camps, respectively (Figure 6b).
RO is the most popular desalinating technology in Greece, as it produces 74.41% of the desalinated
water. ED is used for the desalination of 10.20% of the total desalinated water produced, whereas
MED is used for 8.47% of the produced water and MSF is used for the 6.75% (Figure 6c) [37].
Figure 6. Desalinated water production according to: (a) feed water; (b) its uses; and
(c) the used technology, in Greece. Adapted from [37].
(a) (b) (c)
There are 35 RO plants operating in the Hellenic island municipalities with a total capacity of
22,860 m3/d and operating costs ranging from 0.13 €/m3 to 2.70 €/m3 (Table 7). The newest
desalination plant in Almyros (Iraklion, Crete), with a capacity of 2,400 m3/d, has been in operation
since January 2014. This project is the first one whereby the produced water will be sold by the
contractor to the Municipality of Iraklion, at a guaranteed price of 0.27 €/m3 for five years [38]. Also, a
future upgrading of its capacity up to 20,000 m3/d is planned. Note that the Almyros brackish spring,
from where the plant will be fed, has a capacity more than 620,000 m3/d.
The average operating costs of 30 RO plants of seawater desalination (Table 7) in the Hellenic
islands has been estimated at 0.85 €/m3. More precisely, the 4800 m3/d capacity plant in Leros has a
minimum operational cost of 0.13 €/m3, while the 500 m3/d capacity in Sifnos reaches the highest
registered value of 3.5 €/m3. The range of this cost is depicted in Figure 7 [36].
Water 2014, 6 1144
Table 7. RO desalination plants in Hellenic islands’ municipalities. Adapted from [38].
Project Year Type
Capacity
(m3/d)
Initial
cost (M €)
Operation
cost (€) Contractor Acceptance
Almyros Iraklion 2014 RO & UF 2,400 0.850 0.25 Sychem S.A.,
GR Good
Syros 1st Ermoupoli 1992 RO 800 0.589 2.70 Christ, CH Good
Syros 2nd Ermoupoli 1997 RO 800 1.482 2.70 Christ, CH Good
Syros 3rd Ermoupoli 2001 RO (SW) 40 0.346 2.00 Culligan Greece Good
Syros 4th (Ano Syros) 2000 RO 250 0.215 0.50 Temak, GR Good
Syros 5th (Ano Syros) 2002 RO 500 0.400 0.50 Temak, GR Good
Syros 6th (Ermoupolis) 2002 RO (SW) 2,000 0.313 0.40 Temak, GR Good
Syros 7th (Ano Syros) 2005 RO 1,000 1.000 0.40 Temak, GR Under
construction
Shinousa 2004 RO 100 0.120 0.70 Temak, GR
Under
construction
Mykonos (Korfou) old 1981 RO 500 N/A 2.00 Μetek, ΙΤ Good
Mykonos (Korfou) new 2001 RO 2,000 1.276 0.50 Culligan Greece Good
Paros (Naousa) 2001 RO 1,200 0.415 0.50 Ionics Itaba Good
Tinos (old) 2001 RO 500 0.434 0.62 Culligan Greece Good
Tinos (new) 2005 RO 500 0.376 0.62 Culligan Greece Good
Ia, Santorini 1st 1994 RO 220 N/A 2.00 Matrix, USA Good
Ia, Santorini 2nd 2000 RO 320 0.210 2.00 Culligan Greece Good
Ia, Santorini 3rd 2002 RO 160 N/A 2.00 Matrix, USA Good
Sifnos 2002 RO (BW) 500 0.224 3.50 Hoh, DM Good
Omiroupolis, Chios,
Municipality, 1st 2000 RO (BW) 600 0.205 0.30 Culligan Greece Good
Omiroupolis, Chios,
Municipality, 2nd 2005 RO 3,000 0.710 0.26 Culligan Greece Under
construction
Omiroupolis, Chios,
Municipality, 3rd 2005 RO 500 0.200 0.26 Culligan Greece Under
construction
Nisiros (old) 1991 RO 300 0.572 N/A Μetek, ΙΤ Out of
operation
Nisiros (new) 2002 RO 350 0.295 0.66 Τemak, GR Good
Ithaki, Kefalonia 1st 1981 RO 620 0.264 2.88 Christ, CH Good
Ithaki, Kefalonia 2nd 2003 RO 520 0.587 0.58 Judo, DE Good
Lerou
(Municipal Enterpr.) 2001 RO 200 0.074 0.13 Culligan
Greece Good
Kassopeon
(Municipality) 2001 RO 500 0.170 0.13 Culligan
Greece Good
Posseidonia
(Municipality), 1st 2002 RO 500 0.464 0.56 Culligan
Greece Good
Posseidonia
(Municipality), 2nd 2005 RO 1,000 0.574 0.45 Culligan
Greece
Under
construction
Agios Georgios
(Municipality) 2002 RO 500 0.102 0.30 Culligan
Greece Good
Paksoi (Municipality) 1st 2005 RO 330 0.260 0.51 Culligan Greece Good
Paksoi (Municipality) 2nd 2005 RO 150 0.162 0.59 Culligan Greece Good
Total: 32 - - 22,860 - - - -
Water 2014, 6 1145
Figure 7. Operating cost (€/m3) of seawater RO desalination plants in the Hellenic islands.
Adapted from [36].
The cost of desalinated water in Greece is between 0.5 €/m3 and 3.5 €/m3 [38,39]; however, in most
cases, the cost is above 1.2 €/m3. The cost is relatively higher compared to the cost of large
desalinations plants, like those operating in Israel, Malta, and Cyprus, where the cost is usually below
0.7 €/m3 due to the size of the Hellenic plants and their age [38]. However, as a consequence of the
critical importance of desalinated water, it is expected that the Hellenic Government will subsidize the
electric energy consumed for this purpose. In southeastern Greece, water supply in the future is
expected to be mainly based on desalination. Modern desalination processes of utilizing solar [40,41],
wind [42], or wave [43] energy, instead of fossil fuels, are under development. Desalination plants
utilizing renewable energy sources have also been operating in Greece. Such plants are:
(a) A vapor compression plant charged with a 750 kW wind turbine is located on the island of Symi,
producing 450 m3/d, has been operating since 2009.
(b) A MED plant using geothermal energy was built on the island of Kimolos in 2000. This unit
has a 188 m well and is considered to be a low enthalpy one (61 °C), capable of producing 80 m3/d.
(c) A hybrid RO was constructed on Keratea in 2002, combining wind turbines with
photovoltaic panels. The capacity of this hybrid plant reaches 3 m3/d, while the wind turbines
and photovoltaic cells are of 900 W and 4 kWp nominal power, respectively [23].
(d) Another plant of today’s capacity 3,360 m3/d is on the island of Milos. It is a RO plant which
used the electrical energy needed from an 850 kW wind turbine operating at 600 kW [44].
(e) Finally, on Irakleia island, there is a removable RO desalination plant, which uses both wind
and solar energy through a 30 kW wind turbine and a backup photovoltaic panel system.
7. The Potential of Using Brackish Waters for Desalination in Greece
Several studies indicate that throughout Greece, especially in island areas, millions m3/year of
brackish water are available. Currently the use of brackish water is next to zero. For instance, Crete has
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
Leros
Casopean, (Municipality)
Omiroupolis (Municipality), Chios
Omiroupolis (Municipality), Chios
Omiroupolis (Municipality), Chios
Agiou Georgiou (Municipality)
Distion (Municipality)
Poros (Municipality)
Syros 7th (Ano Syros)
Poseidonia (Municipality)
Syros 4th (Ano Syros)
Syros 5th (Ano Syros)
Mykonos (Korfos) new
Paros (Naoussa)
Paxoi (Municipality) 1st
Paxoi (Municipality) 3rd
Poseidonia (Municipality)
Ithaki, Kefalonia 2nd
Paxoi (Municipality) 2nd
Tinos (old)
Tinos (new)
Nisyros (new)
Shinousa
Syros 3rd (Ermoupoli)
Syros 6th (Ermoupoli)
Syros 1st (Ermoupoli)
Syros 2nd (Ermoupoli)
Ia, Santorini 1st
Ia, Santorini 2nd
Ia, Santorini 3rd
Ithaki, Kefalonia 1st
Sifnos
Cost (€/m3)
Project
Water 2014, 6 1146
an over 1000 hm3/year brackish water potential, while a considerable amount of brackish water also
exists on the Aegean islands.
Only discharges of the well-known source of brackish springs (known as Almyroi) on Crete (Iraklion)
reach more than 1000 million m3/year: one almyros in the west of Iraklion city has an average
discharge of 235 million m3/year, quantities that correspond to 50% of the total annual water used in
Crete [45]. Today, the brackish water is not exploited. Water from the Almyros of Iraklion could be
used even as potable for 45–50 d/year when the TDS < 200 mg/L, which means about 5 million m3/year
of fresh water could be saved [46]. One could draw similar examples from other islands.
The desalination of brackish water is of considerably lower cost, compared to the desalination of
seawater. This cost reduction may be over 50%, mostly because the cost for the removal of dissolved
salt is lower at power salt concentrations [47].
8. Discussion and Conclusions
The global population boom, urbanization and climate change have severely reduced water supplies.
Furthermore, tapping fresh water for metropolitan areas has become more difficult, if not impossible.
Without any doubt, the future relies on the implementation of “NEWater” technologies such as
desalination and direct potable reuse of treated wastewater [27]. Desalination, especially in coastal areas,
is the most cost-effective approach to long-term water supply sustainability, compared with other options.
Desalination of sea and brackish water for both water supply and irrigation in arid and semi-arid
coastal regions of the world seems to be a very promising technology. In fact, desalination is already a
competitive alternative in regards to other options; as the water produced is low-priced in most cases,
energy requirements have been significantly reduced and last but not least, it is friendly to the environment,
especially when the process powered by renewable energy sources. Also it should be noted that the
combination between desalination and renewable energy sources in autonomous independently
operating desalination systems, is a unique solution for water in coastal, relatively isolated areas with
weak and limited possibilities of local energy supply networks.
As far as Greece is concerned, desalination could be a sustainable option to face water scarcity in
the “waterless” islands, especially during the summer months, when there is an increase in water demand.
Given adequate public support, desalination plants could become highly competitive in regards to
alternatives such as water transfer from the mainland. Transfer cost varies from 4.91 €/m3 to 8.32 €/m3
and is currently the main way of meeting deficient water balance of the semi-arid islands [36].
Finally, desalination plants could be used as storage of redundant renewable energy in RES installations.
Today, RO desalination technologies have turned out to be the most appropriate in Greece,
especially for water supply of the semi-arid islands in the southeastern regions of the country.
These technologies have the lowest energy requirements, which can be covered by air turbines or
solar panels, e.g., renewable energy sources are abundant in those areas (such as wind and sun),
and thus burden only to a minimum the rather sensitive local networks and the environment.
Also, RO technologies have limited spatial requirements and are adaptable to changes in productivity.
Their manufacture process is simple, a feature absolutely necessary for installations in limited areas,
where water demands change continuously. Finally, the cost of water, also an important criterion,
is kept low, although it remains somewhat higher than in other desalination processes. However, it remains
Water 2014, 6 1147
lower than the cost of transporting water, while in the case of the hybrid RO system, costs are kept at
the lowest possible level.
Conclusively, the main points that emerge from this study are the following:
(a) The RO desalination costs over the last 15 years have been significantly reduced. The use of
alternative energy sources will further reduce the cost.
(b) Research and technology on the desalination membrane processes will continue to develop in
the years to come to the direction of becoming friendly to the environment and cost effective.
(c) Water demand will continue to increase and desalination and water reuse will be sustainable
options in increasing the low water availability.
(d) Greece has all the potential to move forward in terms of research and technology on water
management internationally and especially in the Mediterranean region, provided there is
investment in relative sectors. Emphasis should be put on the green aspect of the
desalination technology.
(e) The use of desalination technologies to solve the problem of water shortage in the “waterless”
Hellenic islands may lead, under certain circumstances, to the best economic, environmental,
and social results, for both the island environment and the local communities, contributing
substantially to a comprehensive and worth-living growth.
Acknowledgments
Thanks are due to Veolia Environment, Paris, France and Sychem S.A., Iraklion, Greece for the
information provided.
Author Contributions
Konstantinos Zotalis prepared the manuscript and made the data collection; Emmanuel G. Dialynas
made the bibliographical review and contributed to manuscript preparation; Nikolaos Mamassis
analyzed the data and codified the methodology; and Andreas N. Angelakis had the original idea and
supervised the research.
Conflicts of Interest
The authors declare no conflict of interest.
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One of the most pervasive problems afflicting people throughout the world is inadequate access to clean water and sanitation. Problems with water are expected to grow worse in the coming decades, with water scarcity occurring globally, even in regions currently considered water-rich. Addressing these problems calls out for a tremendous amount of research to be conducted to identify robust new methods of purifying water at lower cost and with less energy, while at the same time minimizing the use of chemicals and impact on the environment. Here we highlight some of the science and technology being developed to improve the disinfection and decontamination of water, as well as efforts to increase water supplies through the safe re-use of wastewater and efficient desalination of sea and brackish water.
Recycled water is a reliable source of water that must be taken into account in formulating a sustainable water policy. Water reuse is a growing field and many projects have been occurring throughout Europe in the last fifteen years. Most of northern EU countries have abundant water resources. In this case, the need for extra supply through the reuse of treated wastewater is not a priority, but the protection of the receiving environment is considered as an important issue. The situation is different in the southern EU countries, where the additional resource brought by water reuse promoted the implementation of a number of new projects. One of the major constraints for water reuse and its public acceptance is the lack of relevant legislation at EU level. As a result of this situation, both strict and flexible standards can be found in Europe, even in the same country (Spain, for example), illustrating an important equity issue, which needs to be addressed.
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