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Water Recycling and Reuse in EUREAU Countries:
Trends and Challenges
B. Durham1, H. M. Marecos do Monte2, and A. N. Angelakis3
1Technical Secretary, EUREAU Water Recycling and Reuse Working Group and Veolia Water, 52 rue d’Anjou, 75384
Paris, France. e-mail: bruce.durham@veoliawater.com.
2 Instituto Superior de Engenharia de Lisboa,, Portugal, hmarecos@dec.isel.ipl.pt,
3National Foundation for Agric.l Res., Institute of Iraklio, 711 10 Iraklio, Greece, e-mail: angelak@nagref-her.gr and
Hellenic Union of Municipal Enterprises for Water Supply and Sewerage, 41200 Larissa, Greece, e-
mail:angelak2@otenet.gr.
Abstract. EUREAU is a non-profit Union of National Associations of Water Suppliers and Wastewater Services from
EU and EFTA countries. EUREAU countries depend on appropriately treated wastewater to protect the environment
and ensure that freshwater is available for all applications. Indirect water recycling and reuse through surface and
groundwater bodies is common practice and public health is protected through potable water standards for centuries.
Water recycling and reuse for non potable applications or potable substitution has been practiced in Europe since the
Minoan era (ca. 5000 years ago). It has been also proven internationally in water stressed regions to be a drought proof
source of water and one of the most effective water scarcity solutions. This paper considers: (a) the status of water
recycling and reuse in EUREAU countries, (b) the major challenges, (c) the future views, and (d) successful examples
wastewater recycling and reuse in Europe.
Keywords: EUREAU, Europe, guidelines, Mediterranean region; water, wastewater, recycling, reuse.
INTRODUCTION
Water reuse has a long history in Europe: there are examples of rainwater reuse since the Minoan time, ca.
3,500-1,100 B.C.; wastewater reuse has been practiced since the Ancient Greek and Roman civilizations
(Angelakis and Spyridakis, 1996); wastewater has also been used by the Mediterranean civilizations, for
example in the Milanese Marcites (14th and 15th centuries), in the Valencia huerta and in the North European
countries, like in Great Britain, Germany, France and Poland (Soulié and Tréméa, 1991). Land application of
wastewater is an old and common practice, which has gone through different development stages according
to the state of knowledge, treatment technology and regulations evolution (Angelakis et al., 2005).
Raw or partially treated wastewater has been used for agriculture in many locations all over the world,
improving the yield of crops in agriculture, although in some cases generating serious public health
consequences (endemic and quite epidemic diseases) and adverse environmental impacts. Slow rate
irrigation (SR) systems have a long history in the treatment and disposal of municipal wastewater as they
have been widely employed in the treatment/disposal of municipal wastewater since 1850 (Folsom, 1876).
The expansion of mechanical wastewater treatment plants led to the decline application and development of
SR systems along the last century. However, a renewed interest in the use of SR systems as a wastewater
treatment process has been observed during the last two decades, due to their significant advantages such as
low construction, operation, and maintenance costs especially in small rural communities. SR irrigation
systems may combine wastewater treatment functions with water reuse for agriculture whenever the
vegetation cover of irrigated land has an agricultural interest. In many regions of the world there is a strong
interest on the use of wastewater for agricultural irrigation that has been driven by water scarcity, lack of
nutrients availability and concerns about health and environmental effects (introduced during the 20th
century).
The need for water conservation strategies, such as water recycle and reuse, has been acknowledged by the
UNO and is directly related to the MDGs , especially to the following goals: (1st) Eliminate extreme poverty
and hunger; and (7th) Ensure environmental sustainability.
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Significance of wastewater reuse
The significance of water reuse may be evaluated through the comparison of water reuse potential with total
water use. Water recycling and reuse is generally small compared with total water use but it is expected to
increase significantly. Even though there are limits in its implementation (like the flow entering certain
wastewater treatment plants (WWTP) and the cost of the facilities, specially the distribution networks for
treated wastewater), water reuse greatly improves the management of water resources at a local or regional
scale. Thus, water reuse is expected to become more significant, principally in water scarce regions.
In the United States, it was estimated that municipal water reuse accounted for 1.5% of total freshwater
withdrawals in the year 2000 (Asano et al., 2007). California and Florida are currently the states where water
reuse is more significant, although the practice is extended to many other states in the USA. By the year
2000, Florida’s water reuse programme had grown to 457 treatment facilities with a capacity of 1,542
million m³/yr (Geselbracht ,2003). In California, where the largest number of water reuse facilities existing
in the United States is found, there is around 496 million m³ of municipal wastewater currently reused with,
in 2000, water reuse for agricultural irrigation amounting to 68% of the total recycled water used.
In the year 1996 reused water accounted for 4.3% of available water resources in Tunisia and may reach
11% in the year 2030. In Tunisia, the expected amount of recycled water in the year 2020 is expected to be
approximately 18% of the available groundwater resources and could be used to replace groundwater
currently used for irrigation in areas where excessive groundwater mining is causing salt water intrusion in
coastal aquifers.
In Israel reused water it accounted for 15% of available water resources in the year 2000, and may reach
20% in the year 2010.
The volume of treated wastewater compared to the irrigation water resources is actually about 7% in Tunisia,
8% in Jordan, 24% in Israel, and 32% in Kuwait. Approximately 10% of the treated effluent is being reused
in Kuwait, 20-30% in Tunisia, 85% in Jordan, and 92% in Israel.
In China, where water is reused for agricultural, industrial and domestic (non potable) uses, waster reuse
projects have been increased in number and size in recent years,.
In Japan, water reuse totaled 257.5 million m³/yr in 2003 (Japan Sewage Works Association, 2003). In Japan
water reuse is applied mainly for non-potable urban applications such as toilet flushing, urban environmental
water, and industrial reuse.
Wastewater recycling and reuse in Spain totaled 217 million m³/yr, 86% being reused for agricultural
irrigation. The level of reuse in Spain is expected to reach 1,200 million m³ in 2012.
In EUREAU countries, as in most of the developed countries, indirect potable reuse through groundwater
recharge and surface water augmentation, along with new infrastructure approaches, is inevitable in urban
areas and will represent an essential element of sustainable water resources management (Fig. 1). Moreover,
in the future, rationale for indirect potable water recycling and reuse is inevitable due to the followings
(Asano et al., 2007):
a) Currently, water is under valued, but cost is increasing rapidly. High costs will also foster lower cost
solutions, like sometimes reclaimed water can be, especially for non-potable uses;
b) The value of water will continue to increase in the future (e.g., the Mediterranean islands);
c) De facto indirect potable reuse now occurs and is largely unregulated;
d) Infrastructure requirements limit reuse opportunities;
e) Existing and new technologies can and will meet the water quality challenge;
f) Today treated wastewater represents a reliable alternative water supply source.
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Figure 1. De facto indirect potable reuse is a well
established practice.
Driving forces, benefits and concerns of water reuse in Europe
The driving forces for water reuse development in EUREAU countries are related to different issues such as
water scarcity (water scarce environment threatened by pollution), cost-effectiveness of water reuse or
environmental issues (more stringent water quality discharge regulations). In Europe the demand for water
resources increased 600% during the second half of the 20th century and presently is about 660 km3/year
[Estrela et al, 2001]. About 75% of abstracted
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freshwater in the EU for all uses comes from surface water,
about 25% from groundwater and only minor contributions from reuse of treated wastewater and
desalination of seawater [Krinner et al,1999].
The sustainable use of national water resources implies that the annually abstracted water should not exceed
a certain ratio of the annual renewable water resources. In most of the European continent the amount of
water available largely exceeds water demand. However, renewable water resources in Europe change
widely from northern Atlantic to the Mediterranean Sea as a direct consequence of climate (rainfall and
temperature). As a consequence, severe imbalances between regions are observed: 18% of the EU
population is living in water stressed southern Europe (Cyprus, Italy, Malta and Spain); 9 countries, lying
mainly in southern Europe, which represent 32% of EU population, are moderately water stressed (Belgium,
Germany, Bulgaria, Denmark, Portugal, Romania, Turkey).
The future situation of sustainable water resources will depend basically on the trends of renovation of water
resources and pressure for water abstraction. Renewable water resources will be affected by climate change,
which seems to be a recognised reality at present and by water pollution caused by human activity. Climate
change is expected to reduce water availability and increase abstraction for irrigation in Mediterranean
regions. Under mid-range assumptions on temperature and precipitation changes, water availability is
expected to decline in Southern and South-eastern Europe (by 10 % or more in some river basins by 2030).
Pressures on water abstraction will be affected mainly by the evolution of sectoral water uses (mainly
agriculture), population and urbanisation growth, tourism, industry. The sectoral profile of water abstraction
is expected to change in the long term: abstraction for the electricity sector are projected to decrease
dramatically over the next 30 years as a result of continuing substitution of once-through cooling by less
water-intensive cooling tower systems; industrial water use is likely to stabilise or even decrease; in Eastern
Europe, urban water supply may grow significantly; agriculture is expected to remain the largest water user
in the Mediterranean countries, with more irrigation and warmer and drier growing seasons resulting from
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Abstracted water is the amount of water physically removed from its natural source.
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climate change. The southern part of Europe seems more vulnerable due to low rainfall and the irregular
availability of water resources in time. Water shortage in such European regions affects important economic
activities such agriculture and tourism inducing intensive exploitation of water resources, namely the
aquifers. Severe environmental impacts are drawn by over exploitation of water resources such as pollution
of surface water, depleting the groundwater level, intrusion of seawater into the aquifers, acceleration of the
desertification process, damaging wetlands and habitats.
In one sentence: presently there are regions in several EU member states where water abstraction is
impairing the sustainability of water resources and the environment and the situation tends to aggravate in
the future. Water conservation is the hydrological answer to the problem and certainly water reuse is an
important component of water conservation strategies. The implementation of wastewater recycling, and
reuse promotes the preservation of limited water resources in conjunction with water efficient use and
watershed protection programmes.
Water recycling and reuse is meant to help close the urban water cycle and therefore enable sustainable reuse
of available water resources. When integrated to water resources management, water reuse may be
considered as an integral part of the environmental pollution control and water management strategy. It may
present benefits to public health, the environment, and economic development. Recycled water may provide
significant additional renewable, reliable amounts of water and contribute to the conservation of fresh water
resources. It may be considered as a valuable source of water and nutrients in agriculture schemes and
therefore contributes to reducing chemical fertilizers’ utilization and to increasing agricultural productivity.
Reuse of recycled water, if properly managed, may alleviate pollution of water resources and sensitive
receiving bodies. It may also contribute to protection of agricultural landscapes and desertification control.
Saline water intrusion may be controlled in coastal aquifers through groundwater recharge operations. Other
social and economic benefits may result from such schemes such as employment and products for export
markets.
Water recycling and reuse presents benefits but may induce serious problems, namely related to the content
of trace substances and pathogen content in treated wastewater. Adequate treatment has therefore to be
provided for the intended reuse. The benefits, potential health risks and environmental impacts resulting
from water reuse and the management measures aimed at using wastewater within acceptable risk levels for
the public health and the environment are acknowledged in several documents (Shuval et al., 1986; Mara
and Cairncross, 1989; Asano, 1998; Angelakis et al., 1999; Blumenthal et al., 2000; Angelakis et al., 2003;
WHO, 2006).
GUIDELINES AND/OR REGULATIONS ON WASTEWATER RECYCLING AND REUSE
Background
When planning water reuse projects the level of wastewater treatment is dictated by the intended water reuse
applications (Asano, 1998). Advances in the effectiveness and reliability of wastewater treatment
technologies have improved the capacity to produce reclaimed wastewater that can serve as a supplemental
water source, in addition to achieve water quality protection and pollution abatement requirements. In
developing countries, particularly those in arid parts of the world, reliable low-cost technologies (both for
treatment and reuse) are needed for acquiring new water supplies and protecting existing water sources from
pollution (Marecos do Monte et al., 1996).
As for any activity related with the environment the development of standards, criteria, rules, guidelines,
good practices, and other is essential to regulate wastewater recycling and reuse planning, design and
operation.
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In several countries and states in the United States, water reuse is well established and the value of reclaimed
water has been fully recognized. In these countries and states, laws and regulations exist that mandate water
reuse under certain conditions. In several states, regulations require that a study should be conducted to
investigate the possibility of using reclaimed water for applications that currently use potable water or
freshwater (Crook, 2002). In the United States, as of March 1992, 18 states have adopted regulations
regarding the use of reclaimed water, 18 states had guidelines or design standards, and 14 states had no
regulations or guidelines (US EPA, 1992 and 2004).
Historical Developments
The evolution of reuse good practice and guidelines cannot be understood completely without a historic
review of the standards that have been created since 1918. In this year the legislative fever on wastewater
reuse in California started. A summary of this evolution can be found in Table 1.
Table 1. Historical data of the water quality for unrestricted irrigation (Salgot and Angelakis, 2001)
Year
Data and quality criteria
1918
California State Board of Public Health set up the "First regulations for use of sewage for irrigation
purposes in California"
1952
First regulations of Israel
1973
WHO 100 FC/100 mL, 80% of samples
1978
State of California wastewater reclamation regulations: 2.2 TC/100 mL
1978
Israel regulations: 12 FC/100 mL in 80% of samples: 2.2 FC/100 mL in 50% of samples
1983
World Bank Report (Shuval et al., 1986)
1983
Florida State: No E. coli detection in 100 mL
1984
Arizona State: Standards for virus (1 virus/40 L) and Giardia (1 cyst / 40 L)
1985
Report of Feachem et al., 1983
1985
Engelberg Report (IRCWD, 1985)
1989
WHO Recommendations for wastewater reuse: 1000 FC/100 mL 1 nematode egg/L
1990
Texas State: 75 FC/100 mL
1991
Sanitary French recommendations: Based on WHO
1992
US EPA Guidelines for Water Reuse: No FC detection in 100 mL (7 d median. No more of 14 FC/100 mL
in any sample)
2000
State of California Criteria (Title 22) was revised
2003
WHO State of the Art Report on Artificial Recharge of Groundwater with Recycled Water (Aertgeerts and
Angelakis, 2003)
2004
Revised US EPA Guidelines for Water Reuse
2006
WHO Guidelines for using Treated Wastewater in Agriculture
For many years, the State of California regulations were the only legal reference for wastewater recycling
and reuse. They became the benchmark for water reuse practice everywhere in the world with the
assumption that they were the truth, axiomatic and indisputable. During the seventies and eighties, some
evolution took place and the different states in the USA, and several international agencies, like the World
Bank and the WHO were extremely active. After the publication of the US EPA recommendations in 1992,
little evolution has been made. In Europe there is some legislative movement for wastewater recycling and
reuse in the EU (Salgot and Angelakis, 2001; Marecos do Monte, 2007).
As mentioned previously, California has been the only state that has water reuse regulations for decades,
consequently it has been considered to be the best by many technicians and scientists. Nevertheless, the
considerable cost of its implementation should be considered taking into account that this legal piece is very
restrictive and was adopted under conservative temporal, legal and socio-economic pioneer circumstances.
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Several supranational entities have been discussing the possibility to implement new guidelines and
regulations, different from California ones or suggest modifications. WHO (1989) and the World Bank
sponsored several studies on this issue. Later on, the US EPA also sponsored several studies and compared
the existing state laws, issuing recommendations in 1992 (US EPA, 2004). At present time, both California
and Israel regulations are under revision. In addition, a committee of experts has been established for an
initial revision of the WHO guidelines. Finally, in Europe various studies are in progress for establishing
guidelines or regulations in various countries such as UK, Belgium, Greece and Spain. In 2005 Portugal has
published NP 4434:2005, the Portuguese national standard on water reuse for irrigation (Marecos do Monte,
2007).
WHO Guidelines for Wastewater Recycling and Reuse
In contrast to the California approach, some international organizations such as the World Bank and WHO
call for epidemiological studies to defend the less stringent guidelines for wastewater treatment.
Microbiological monitoring requirements also vary: the WHO guidelines require monitoring of intestinal
nematodes whereas the California criteria rely on the required treatment systems and the sole monitoring of
the total coliform count to assess microbiological quality (Asano and Levine, 1996). Similarly, the US EPA
criteria emphasize fecal coliforms removal.
Pathogens are difficult (and expensive) to monitor. Therefore, the WHO guidelines, prepared to keep the
needs of developing countries in mind, only prescribing a limit for faecal coliforms (<1,000/100 mL) and
intestinal nematodes eggs (1/L). As a consequence, the whole argument about standards revolves around
the validity of such limits as a sufficient guarantee of safety for the water used in irrigation (Marecos do
Monte et al., 1996). A large part of the answer lies in the treatment requirements and on the reliability of
each treatment process associated to the limit values. One must also realize that the WHO guidelines, are
already a major step forward in the case where raw wastewater is directly reused, merely by requiring
treatment.
Based upon an extensive analysis of existing guidelines WHO reported the need for developing health-
related chemical criteria for land application of reclaimed wastewater. Blumenthal et al. (2000) have
developed recommendations for revising WHO (1989) guidelines taking into consideration empirical
epidemiological evidences and studies measuring real exposures that occur over time and based on
experimental data. In September 2002, WHO in collaboration with EUREAU has organized a Workshop in
Iraklio, Greece on water recycling and reuse in Mediterranean region. A draft of guidelines on water
recycling and reuse in the Mediterranean region was proposed in this workshop (Bahri and Brissaud, 2002).
The revision of the 1989 WHO guidelines for reuse of treated wastewater for agricultural has been published
recently (WHO, 2006). In addition to reuse of treated wastewater for agriculture, the revised WHO
guidelines include reuse for urban settings, aquaculture and artificial recharge of groundwater. In the revised
WHO guidelines emphasis is given to both relevant epidemiological studies and risk assessment.
Legislation and guidelines for wastewater recycling reuse at EU level
The European Commission has issued no regulation, quality guidelines or good practice code on wastewater
reuse up to present. However reference to reuse is made in the article 12 of the Urban Wastewater Directive
(UWWD) (EU, 1991) stating: “Treated wastewater shall be reused whenever appropriate”. In order to make
this statement reality, common definitions of what is “appropriate” are needed. The EU Water Framework
Directive (WFD) introductory booklet “Tap into it!” (Tap into it! ISBN 92-894-1946-6) states on page
8:“Living with water Scarcity - as water shortage increases worldwide, people are looking for ways to reuse
water. This makes sense because it allows a double use for the same pumping costs and mandatory
wastewater treatment costs… reuse is an important and natural method of managing water drainage”. The
WFD (WFD Directive 2000/60/EC) states“ The following is a non-exclusive list of supplementary measures which
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Member States within each river basin district may choose to adopt as part of the programme of measures required
under Article 11(4): (x) efficiency and reuse measures, inter alia, promotion of water-efficient technologies in industry
and water-saving irrigation techniques (EU, 2000). Although the WFD does not include reuse in the body of the
directive it introduces a quantitative dimension to water management, on top of the usual qualitative
dimension, which may stimulate the consideration of wastewater reuse. It also states “water resources
should be of sufficient quality and quantity to meet other economic requirements”. Wastewater reuse being a
water resource often mobilised for economic reasons, such a statement does have economic implications
(Angelakis et al., 1999). The Integrated Pollution Prevention Control legislation (IPPC) does encourage
water reuse and is included in the legislation within the WFD.
Treated wastewater is nowadays regarded worldwide as water resource and not as a waste for disposal. The
principles of the WFD should fuel the discussion on treated wastewater use, management and its economic
analysis which will give to the treated wastewater the prospective of an economic good. The WFD discusses
fresh water, but as treated wastewater is a by-product of potable water use, it can be analogously extended to
cover treated wastewater (as a product of wastewater treatment). This entails applying on reclaimed
wastewater all the principles and articles concerning other water sources management. Reclaimed water
demand is expected be growing with time at higher rates than supply, when relevant projects being
implemented. Thus, the WFD could evidently be extended to cover treated wastewater as water resource
(Tsagarakis, 2005).
There are many different attitudes towards treated wastewater reuse across Europe. There is now an effort to
harmonize the various approaches to wastewater reuse at European level (Angelakis et al., 2003) just as the
Australians have combined their different state guidelines to produce national guidelines and best practice in
2006. Recently, an EU MED Working Group on Water Recycling and Reuse has been established by EU
DG ENV. The first task undertaken by this working group is the preparation a brief report that focuses on
issues that are important to EU Water Directors and is supported by the evidences developed in EU and
internationally.
EXAMPLES OF WASTEWATER RECYCLING AND REUSE IN EUREAU COUNTRIES
The potential for reuse of treated wastewater in EUREAU countries varies according there specific
circumstances (climatic, socio-economic, etc.). In EUREAU countries Spain shows the highest reuse potential, the
calculations suggesting a value of over 1,300 Mm³/yr in 2025. Italy and Bulgaria both exhibit estimated reuse
potentials of approximately 500 Mm³/yr. Some examples of efficient water reuse in EU countries are the
following:
Belgium. The IWVA Torreele indirect potable water reuse through dune infiltration and aquifer recharge
project is providing 40% of the potable water demand. This is an outstanding achievement for a small but
highly innovative European water operator. The unusual aspect of this project is their high level of
communication and involvement with the community prior to, throughout the project and during the three
years of operation. This has reinforced a high level of trust and acceptance of indirect potable reuse within
the community. IWVA also have a commitment to search out international experience and share their
experience at leading conferences in most parts of the world (IWVA, 2005).
Cyprus. In Cyprus the wastewater generated by the main cities, about 25 million m3/yr, is planned to be
collected and used for irrigation after tertiary treatment. Because of the high transportation cost, it is
anticipated that most of the recycled water, about 55 to 60%, will be used for amenity purposes like hotel
gardens, parks, golf courses, etc. A net of about 10 million m3 is conservatively estimated to be available for
agricultural irrigation. The cost of recycled water is low, about 0.07 €/m3. This will reportedly allow
irrigated agriculture to be expanded by 8-10% while conserving an equivalent amount of water for other
sectors (EUREAU, 2005).
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Germany. Berlin has operated like many large cities / river basins with a partly closed water cycle for
hundreds of years through a combination of careful wastewater treatment and the benefits of soil aquifer
treatment through bank filtration to produce potable water from the aquifers. The NASRI research project
(www.kompentenz-wasser.de) was set up to study the fate of pathogens and organics, geochemical processes
and the hydraulics of bank filtration and artificial recharge systems at laboratory, semi technical and field
scale. The outstanding feature of this project is the multi-stakeholder involvement which includes the water
utility with local universities and the environmental regulator.
Greece. In Greece, more than 65% of the Greek population is connected today to over 350 centralised
WWTP with a total capacity of over 1.45 Mm3/d (Tsagarakis et al., 2001). An analysis of data concerning
the water balance of the areas of the treatment plants demonstrated that more than 83% of the treated
effluents are produced in regions with a deficient water balance. Therefore, treated wastewater reuse in these
areas would satisfy an existing water demand. Several mainly small projects on wastewater recycling and
reuse are in practice, such as in Archanes, Chalkida, Kos, Hersonissos, and Thessaloniki. Few other projects
are under planning, such as Iraklio, Agios Nikolaos and several Aegean cities. The effluent from those
projects is mainly used for irrigation (both agricultural and landscape) and is less than 0.50% of the
irrigation water used in all over the country (7000 Mm3/yr). However, the potential for wastewater recycling
and reuse in Greece is very high estimating in 5% of the irrigation water demand. Also, several indirect
reuse projects are in use in the central Greece (such as Larissa, Trikala, Karditsa, Lamia, and Tripolis).
However, no guidelines or criteria for wastewater recycling and reuse have been yet adopted beyond those
for discharge (No E1b/221/65 Health Arrangement Action). A preliminary study on the necessity for
establishment of criteria in Greece has been implemented. Proposed criteria are aimed to increase protection
of human health and environment (Tsagarakis et al., 2003).
Italy. The practice of wastewater use for irrigation in Italy is known since the early years of the century XX,
although such practice decreased due to the low quality of water. Agriculture is the major interest for reuse
in Italy. At present there are over 4000 ha irrigated with treated wastewater in Italy [EPA, 2004]. There are
favourable conditions to implement reuse projects in Italy because 60% of the urban wastewater is treated in
medium and large plants (treating more than 100 thousand people) that produce adequate quality effluents at
a reasonable cost (EPA, 2004). One of the largest projects was implemented in Emilia Romagna where 400
ha are irrigated with treated wastewater. 16 new reuse projects are being implemented in Sicily and Sardinia
(Grammichele, Palermo, Gela).
Existing Italian legislation (General Technical Standards - G.U. 21.2.77) sets very strict parametric values
and has been a constriction to the development of water reuse projects in the country. New legislation is
being prepared that gives better attention to the management of water resources and in particular to the reuse
of treated wastewater.
Water reuse for industry is practiced in the metropolitan area of Turin. Municipal WWT operator companies
have already planned to build a separate supply network for wastewater reuse for industry (Azienda Po
Sangone and CIDIU) in the Turin metropolitan area (Marecos do Monte, 2007).
Malta. Since 1983, the treated wastewater from the Sant Antnin sewage treatment plant has been used for
irrigation. The current output of 10,800 m3/d is expected to be increased to 17,000 m3/d after expansion of the
plant. The plant uses an activated sludge process followed by rapid sand filters (9 m3/m²·h). The water is then
disinfected with gaseous chlorine (12 mg/L and contact time 30 min) and pumped into irrigation reservoirs
with a free chlorine residual ranging from 0.1 to1.0 mg/L. The so treated wastewater is used to irrigate 600
ha of crops by furrow and spray irrigation (EUREAU, 2005). The water quality is suitable for unrestricted
irrigation and is used to produce potatoes, tomatoes, broad and runner beans, green pepper, cabbages,
cauliflower, lettuce, strawberries, clover, etc. Three major WWTP are implementing in the country and there
is a plan for water reuse all the effluent produced.
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Portugal. In spite of the fact that Portugal is not bathed by the Mediterranean Sea the Portuguese climate
presents some features of Mediterranean climate particularly in the half of the country south of river Tagus.
Under a natural regime 57.5% of the country mainland suffers a water deficit. Recurrent droughts severely
affect the southern Portugal. The major water reuse interest in Portugal is for agriculture and landscape
irrigation [Marecos do Monte, 1998]. Presently there are just a few small cases of reuse for agriculture
irrigation, road construction and car washing. However, the interest for the irrigation of golf courses has
increased significantly in the last couple of years. The most important reuse projects are for the irrigation of
golf courses are under implementation in the region of Algarve a tourist region in the south of Portugal.
According to the studies the effluent flow of 14 WWTP is sufficient to cover the water demand for irrigation
of the existing 28.5 golf courses of 18 holes and the planned 19 golf courses (Martins et al, 2006).
Guidelines for water reuse for irrigation were recently published in Portugal (NP 4434:2005) [IPQ, 2005].
This Portuguese standard provides guidance on the use of treated urban wastewater agricultural irrigation
(crops, forest, plant nurseries) and landscape irrigation (parks, gardens, sport lawns such as golf courses). It
is the first regulation in the country that presents not only quality criteria for treated urban wastewater for
irrigation but also provides guidance on other important aspects to ensure safe practice, e.g. for selection of
irrigation equipment and methods, guidelines for environmental protection and includes environmental
impact monitoring procedures in areas irrigated with treated urban wastewater.
A Technical Guide on Reuse of Reclaimed Water is expected to be published by the end of 2007 in Portugal.
This guide focus on several reuse applications such as irrigation, urban uses (street washing, fire fighting),
recreation and environmental uses, that show a potential interest in Portugal.
Spain. In Spain more than 150 wastewater reuse projects have been implemented last years. There is more
wastewater reuse experience in Spain than any other region of Europe, which is summarized as follows:
(a) Canary Islands, driven by a high and perhaps more realistic value of water
(b) Murcia, by calculation that the economic impact to the agricultural industry of aquifer over abstraction,
saline ingress and subsequent soil salinisation was 120 million $/yr (Latorre, 2002).
(c) Barcelona, probably the largest reuse project in the world with a visionary water resource management
solution by combining direct aquifer recharge for control of seawater ingress with river, wetlands and
irrigation to recharge the river basin aquifers.
(d) Costa Brava. A steady growth through a large network of water and wastewater utilities in the Consorci
de la Costa Brava that have developed a large number of reuse projects in most applications by building
local expertise and trust in the region.
(e) Vitoria. The greatest single agricultural reuse project in Europe for high-value crops with Title-22
treatment. 35,000 m3/d were supplied for irrigation of 3,500 ha in the first phase (1995-2004), whereas in
the second phase the irrigated surface will be expanded to other 6,500 ha thanks to the 7 million m3
reservoir just for reclaimed water recently built and that will store the reclaimed water produced off the
irrigation season.
Sweden. In spite of its high availability of water resources, in the southeastern region of Sweden there is an
interest for reusing the tertiary treated effluents of WWTP for irrigation [EPA, 2004]. The reason for this
practice in Sweden is due to the fact that precipitation is low in this part of the country and the effluent reuse
contributes to preserve coastal receiving waters and to conserve groundwater for nobler uses. There are over
40 reuse projects consisting of effluent storage up to 9 months in large reservoirs before being used for
irrigation. In some cases the effluent is blended with surface water.
United Kingdom. The UK is another example of an European member-state apparently rich in renewable
water resources where a strong interest for water reuse had led to some interesting projects including indirect
potable reuse [EPA, 2004] as well as direct reuse for golf courses and road verges irrigation, cooling, fish
farming, car washing. The Millennium Dome in London is an example of a demonstration project of water
reuse as it accommodates the so-called “Watercycle” project where run-off water, grey water and polluted
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groundwater are treated in three treatment lines to a high quality level and subsequently reused in more than
600 toilets and 200 urinols.
CONCLUSIONS
Several EU countries have a long history on water reuse. On the other hand, water reuse development is
related to different issues such as water scarcity, economical, or environmental issues. Today several
countries are adopting an Integrated Water Cycle Management (IWCM) strategy having looked at the
different approaches around the world. Many counties are also changing their institutional and regulatory
framework to avoid overlapping regulation, confusion and to encourage IWCM. One of the key parts of
IWCM is water reuse. In EU it must be promoted easy ways for guidelines and best practice to be added to
the UWWD without creating excessive workload or “too difficult” barrier. These guidelines must make it
easier for the next important projects like Depurbaix in Barcelona or Torreele in Flanders to be implemented
with the advantage of proven European best practice. The greatest challenge we face will be to build a
culture for reuse within government departments to support efficient water reuse projects. EUREAU was
suggested that there would be no progress on reuse in Europe unless the Water Directors added reuse to their
agenda. Today these procedures are in progress.
ACKNOWLEDGMENTS
Thanks and appreciations are due to Mr. Lluis Sala for his critical review of this paper.
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