Olive Mill Waste Case Study Analysis

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Fostinone, L. Li, Y. Liu, X. Mišić, M. Paterakis, C. Phadtare, M. Venkat, K.
Wuennenberg, L.
June 2015
OLIVE MILL WASTE:
CASE STUDY ANALYSIS
FOR LESVOS ISLAND, GREECE

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Acronyms
BOD Biological Oxygen Demand
COD Chemical Oxygen Demand
EC European Commission
EU European Union
GI Germination Index
IWG Industry and Waste Group
MSW Municipal Solid Waste
NAIAS North Aegean Innovative Actions and Support
OMW Olive Mill Waste
OMWM Olive Mill Waste Management
OMWW Olive Mill Waste Water
OMWT Olive Mill Waste Treatment
OMP Olive Mill Pomace
SDP Solid Defatted Pomace
WWTP Wastewater Treatment Plants

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Table of Contents
1 INTRODUCTION ...................................................................................................................5
2 METHODOLOGY .................................................................................................................13
2.1 LITERATURE REVIEW...................................................................................................................... 13
2.2 DATA ANALYSIS.............................................................................................................................. 14
2.3 INTERVIEWS.................................................................................................................................... 15
2.4 SPATIAL ANALYSIS USING ARCGIS.................................................................................................. 16
2.5 CONSTRAINTS AND LIMITATIONS................................................................................................... 17
3 OLIVE OIL PRODUCTION..................................................................................................18
3.1 GLOBAL OLIVE OIL INDUSTRY....................................................................................................... 18
3.2 OLIVE OIL INDUSTRY IN GREECE .................................................................................................. 18
3.3 PRODUCTION OF OLIVE OIL .......................................................................................................... 18
3.4 THREE-PHASE PROCESSING ........................................................................................................... 19
3.5 TWO-PHASE PROCESSING............................................................................................................... 19
3.6 TERMINOLOGY: WASTE AND BYPRODUCTS.................................................................................... 19
4 ENVIRONMENTAL CHALLENGES...................................................................................22
4.1 OLIVE MILL WASTEWATER (OMWW)............................................................................................ 22
4.2 OLIVE MILL POMACE (OMP).......................................................................................................... 22
5 ENVIRONMENTAL IMPACTS OF OLIVE OIL BY-PRODUCTS.......................................24
5.1 IMPACTS OF OMWW DISPOSAL ON THE AQUATIC ENVIRONMENT ................................................ 24
5.2 IMPACTS OF OMWW DISPOSAL ON SOIL......................................................................................... 25
5.3 IMPACTS OF OMWW ON AIR .......................................................................................................... 25
5.4 ENVIRONMENTAL IMPACTS OF OLIVE MILL POMACE (OMP) ........................................................ 25
6 LEGISLATION ......................................................................................................................27
6.1 OVERVIEW OF OMWW LEGAL FRAMEWORK: EU, GREECE AND LESVOS...................................... 27
6.2 THE EU LEGAL FRAMEWORK OF WASTE AND WATER .................................................................. 27
6.3 IMPLICATIONS OF THE EU POLICY FOR GREEK NATIONAL LEGISLATION.................................... 30
6.4 OMWW MANAGEMENT POLICY AND PLANNING, LESVOS ISLAND ............................................... 31
7 SITUATION ANALYSIS ON LESVOS ..................................................................................33
7.1 OVERVIEW OF WASTESTREAMS, INDUSTRIES AND PRACTISES ....................................................... 33
7.2 MUNICIPAL SOLID WASTE .............................................................................................................. 33
7.3 PRODUCTION OF URBAN SOLID WASTE ......................................................................................... 33
7.4 DISPOSAL........................................................................................................................................ 35
7.5 INDUSTRIAL WASTE PROPORTIONATE TO TOTAL WASTE PRODUCTION....................................... 37
7.6 TOTAL MUNICIPAL WASTE WATER .................................................................................................. 37
7.7 MUNICIPAL WASTE WATER PRODUCTION: ...................................................................................... 37
7.8 DISPOSAL OF MUNICIPAL WASTE WATER ........................................................................................ 37
7.9 INDUSTRIAL WASTE WATER AS A PART OF THE TOTAL WASTE WATER ............................................ 38
7.10 OLIVE OIL WASTE MANAGEMENT............................................................................................. 40
8 SOCIAL CONTEXT ANALYSIS ............................................................................................43
8.1 OVERVIEW FROM INTERVIEWS ....................................................................................................... 43
8.2 KEY INSIGHTS................................................................................................................................. 44
8.3 POMACE PELLET FACTORY:.................................................................................................... 45
8.4 POSSIBLE IMPLICATIONS................................................................................................................. 47

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9 CASE STUDY: FACTS THAT ENABLED SPAIN TO TREAT ITS OMW............................49
9.1 POLICY AND FINANCIAL AID.......................................................................................................... 49
9.2 MILL GEOGRAPHIC DISTRIBUTION AND COOPERATION ............................................................... 50
9.3 TECHNOLOGY ADVANTAGE........................................................................................................... 51
10 FEASIBILITY OF TREATMENT OPTIONS........................................................................52
10.1 PRE-TREATMENT........................................................................................................................ 54
10.2 EVAPORATION PONDS................................................................................................................ 54
10.3 LIMING AND SEDIMENTATION ................................................................................................... 55
10.4 UTILIZATION.............................................................................................................................. 56
10.5 IRRIGATION................................................................................................................................ 56
10.6 COMPOSTED OLIVE MILL POMACE............................................................................................ 57
10.7 FROM POMACE TO ENERGY....................................................................................................... 58
11 FEASIBILITY OF IMPLEMENTATION..............................................................................60
11.1 METHODOLOGY......................................................................................................................... 61
11.2 PROCEDURE OF ANALYSIS: SOLUTIONS FOR LESVOS ................................................................. 65
11.3 TRANSITION OF OLIVE MILLS TO TWO-PHASE PROCESSING ....................................................... 65
11.4 TREATMENT SOLUTIONS FOR CLUSTERED THREE-PHASE OLIVE MILLS...................................... 66
11.5 TREATMENT OPTIONS FOR REMAINING THREE-PHASE OLIVE MILLS .....................................70
11.5.1 CO-TREATMENT OF OMWW WITH URBAN WASTEWATER ........................................... 70
11.5.2 POLYPHENOLS EXTRACTION AND INDUSTRIAL USE .................................................... 71
12 RECOMMENDATIONS........................................................................................................73
13 CONCLUSION ......................................................................................................................76
14 REFERENCES.......................................................................................................................80
15 PERSONAL COMMUNICATIONS.......................................................................................87
16 APPENDIX ............................................................................................................................88
16.1 OLIVE WASTE GROUP TASK ........................................................................................................ 88
16.2 STAKEHOLDERS INTERVIEWS..................................................................................................... 90
16.3 JUSTIFICATION FOR FINAL SOLUTIONS .................................................................................... 101
16.4 PHYSICOCHEMICAL TREATMENT ............................................................................................. 102
16.5 BIOLOGICAL TREATMENT........................................................................................................ 103
16.6 OXIDATION AND ADVANCED OXIDATION PROCESSES ........................................................... 103

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1 INTRODUCTION
The research question central to this report is outlined below. What follows is a brief overview
of: characteristics of the Island of Lesvos, the significance of olive cultivation, production and
consumption of olive oil, the challenges and impacts as these relate to Lesvos Island, potential
solutions to olive mill waste, and a brief description of the purpose and sections of this report – these
sections will provide a deeper synopsis for the reader of aforementioned topics.
Greece’s Lesvos Island has a population of 86,436 (National Statistical Service of Greece 2011),
and is located in the north eastern Aegean Sea at 39°10′N 26°20′E. With a coastline of 370 km and an
area of 1,632 km2
(LI 2015), the island is Greece’s third largest, with its capital situated in Mytilene.
The Mediterranean sits at the heart of olive oil production contributing 99% of the globe’s
supply (Alfano et al. 2007), with 95% of the globes cultivated olive trees (Prosodol 2012). The region
has had a long history of cultivating olive trees, see Figure 1, and using olive tree products such as
fruits and oils both domestically and for export. The top three global olive oil producers and respective
European production (by proportion) include: Spain at 50%, Italy at 28% and Greece at 22% (EC
2012). Both international production and consumption of olive oil has expanded to a global scale,
indicated by Figure 2.
Research Question
Within the current context, what transitional pathways exist for
Lesvos Island to effectively treat Olive Mill Waste?
Figure 1: Olive Tree Cultivation, Mediterranean: 1936. Bull 1936

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In terms of Greece’s role within the industry – the nation has more than 132 million olive trees,
producing approximately 350,000 tons of olive oil annually, 82% of which is extra-virgin (Prosodol
2012). Greece is also the world’s top producer of black olives and looks to the Pelopennese, Crete,
Aegean and Ionian Islands for critical supply (Prosodol 2012).
Lesvos Island is a key contributor to the nation’s historical and current olive cultivation and
olive oil production with 1
/3 of it’s landscape under 600 mASL covered by olive trees (Schaelicke pers.
comm. a). This has and, although decreasing over recent decades (see Figure 3), still remains a
substantial part of rural heritage and employment with small-sized family owned groves and processing
mills forming a significant part of the landscape. Active olive cultivation is supported by 28.5% of the
Figure 2: Global Oilve Oil Production and Consumption. TN 2015

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Island’s land surface, with 26% of this allocated to organic production, with speculation for market
increase driven by demand (Schaelicke pers. comm. a.).
Equally significant is the economic contribution the Island’s olive industry makes through
supplying 1
/7 of Greece’s total production and 1% of the globe’s total olive oil supply (Schaelicke pers.
comm. a.). Given Greece is the globe’s third largest olive oil producer, Lesvos’s contribution is crucial
to the Island’s and nation’s economy and identity.
However, the industry does not exist without some significant challenges and impacts, at the
forefront of these is Olive Mill Waste (OMW) as reflected in this report’s Problem Statement below:
OMW in Lesvos is created during the winter season each year by the process of converting
olive fruits to olive oil. A three-phased decanter process is adopted, resulting in products of oil (18.4%),
liquid OMWW (45.8%) and semi-solid OMP (35.8%) (Schaelicke pers. comm. a.). Both OMWW and
Figure 3: Olive Production and Mills, Lesvos: 1984-2014. Schaelicke pers. comm.
Problem Statement
Currently all 54 Olive Mills on Lesvos Island do not treat
wastewater and solid waste (pomace). As a consequence, untreated
Olive Mill Waste is discharged into streams, rivers, bays and the sea
every November to March period.

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OMP are high in polyphenols, making it highly recalcitrant and toxic to humans, animals and plants
(Kistner et al 2004). OMW on Lesvos Island has historically, and continues to be disposed to
waterways in an untreated form, effectively failing to meet EU and national legislation around pollution
limits, as well as compromising the ecosystem.
Attempts at treating OMW on the Island have been made in the past however, these have
unfortuntely not been successful. Expressed as a brief timeline, these include (Schaelicke 2015):
Up to 1999 Two mills, Alyfanta, Stipsi, treated OMWW by flocculation using lime for sediment
settling. Neither plant is operating today;
2004 Three mills, Vasilika, Afalonas, Anemotia, treated OMWW using a settlement tank
aiding natural separation of the solids, oils and liquid. In addition, subsoil infiltration
fields or anaerobic ponds were constructed to more fully manage the liquids. This
demonstration project formed part of a Research Program by the North Aegean
Innovative Actions and Support (NAIAS) and was based on a method proposed by the
Waste Management Laboratory of the University of the Aegean. None of these plants
are operating properly today;
2008 10 private mills, as part of a private enterprise, treated OMP through centralizing to
develop compost for fertilizer. Land close to the Gulf of Gera was purchased and
received local authority permission to be used in this manner. The company was sold
in 2011/12, following a breakdown in relationships and knowledge sharing between
the company and technical partner. The company no longer operates today.
2009 A mill in Pigi treated OMWW using a settlement tank and natural separation of the
solids, oils and liquid. In addition, two subsoil infiltration fields were constructed to
further treat the liquid waste. This demonstration project used the method proposed
by the Waste Management Laboratory of the University of the Aegean. There is no
current data to support whether this mill continues to treat OMWW today.
In addition to these attempts of Olive Mill Waste Treatment (OMWT), there are three pomace
treatment factories on the Island. All three take in three-phase pomace, of these:
 Two factories have capacity to handle the entire Island’s pomace waste. The aim of
these factories is to extract olive oil by drying out the pomace using organic dissolvent.
 One factory, established in 2012, is ready to treat two-phased pomace and anticipates
legislation and enforcement, will result in a doubling of capacity whereby olive mill
owners will be required to transition to two-phased processes where viable. This

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factory dries the pomace and produces three different qualities of biomass (one in the
form of pellets), as well as secondary pomace oil that is sold to the Italian market (due
to legal restrictions on use of secondary extracted pomace oil in the Greek food
industry). This factory is currently experimenting with composting.
There are a variety of reasons why OMW is not responsibly addressed in Lesvos, these are
outlined below in Figure 4 and expressed as a simple PESTLE analysis using current available literature
and stakeholder interviews as discussed in the methodology section.
The PESTLE results linked to the Problem Statement is significant because:
a) Olive mills are failing to comply with current EU and national regulation on waste disposal
limits;
b) It is assumed from evidence elsewhere, but yet to be scientifically monitored on Lesvos Island,
that OMW is potentially harmful to water sinks and biodiversity - continual disposal of
Figure 4: PESTLE Analysis Results.

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untreated waste with high levels of BOD, COD and polyphenols are likely to result in
environmental degradation;
c) Treatment options for OMW are practiced by other significant olive oil producers such as in
Spain and Italy, and even other parts of Greece such as Crete – solutions towards more
responsible OMW management do exist;
d) Broader solutions with co-benefits may exist where OMW is viewed as a resource and as
essential byproducts for feed-in stock of marketable goods creates new industries and revenue
streams for the Island while solving serious environmental and non-compliance OMW issues.
Such products already exist such as biomass grains and pellets for industrial and household
heating. Others might include saleable compost and extraction of polyphenols for the high-
end cosmetic market.
The focus of this report is OMW on Lesvos Island: where and how it is produced and possible
mitigation practices to manage the byproducts more effectively. Our specific Research Question is:
In terms of a methodological approach for this report, substantial literature research was
carried out, including the analysis of data and material provided by the Aegean University. A more
extensive desktop review was undertaken examining the global, national and local context. Here
various case studies were looked at more deeply to examine possible solution options for Lesvos, with
the case of Spain studied more extensively. GIS maps were produced from this combined data and a
process of elimination was devised to ascertain possible treatment options for all 54 mills on the island.
Options also examined other waste streams on the island especially that of key industries such as
poultry and dairy farms as well as slaughter homes and distilleries. Four stakeholder interviews were
carried out with representatives from: Olive mills (two mill Owners), pomace factory (one pomace
factory manager responsible for pellet manufacturing) and a regional administration representative
from the Region of North Aegean (responsible for enforcing business compliance and operating
approvals).
Constraints naturally restricted a more comprehensive report, these include but are not limited
to:
 Time allocated for the exercise;
Research Question
Within the current context, what transitional pathways exist for
Lesvos Island to effectively manage Olive Mill Waste?

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 Lack of prior knowledge especially in Greek language, culture and technical arenas;
 Available and accessible data;
 Assumptions based on social structure requiring deeper social research to prove/disprove.
OMWT solutions in any context are challenging. Literature states that 150+ patented
techniques were developed to address OMW during 1969-2003 – however, high cost prohibits
universal adoption of these solutions (Niaounakis and Halvadakis 2004). The Island of Lesvos is
particularly challenging due to the geographic confines and dispersal as well as the prevailing social and
governance mindsets existing. However, a number of treatment options and broader use of byproducts
are described in this report, many of these were eliminated based on justifications of unsuitability and
expense. The report does narrow down solutions for mills, and integrates GIS mapping to showcase
final results including:
 Conversion from three- to two-phase processing and enabling of OMP utilization;
 Sedimentation ponds for OMWW treatment and subsequent irrigation;
 Evaporation ponds for OMWW treatment;
This report seeks to provide an overview of the current state and possible management options
for the olive oil industry’s byproducts in the form of wastewater and solid waste, for the island of
Lesvos, Greece. The Waste and Industry Group under the MESPOM Ecosystem Management Course
of the University of the Aegean, was tasked with analyzing product process and developing alternative
options for management of current olive mill waste and byproducts taking into account socio-
economic and geographical constraints, as outlined in Appendix A.
This report does not seek to provide a ‘one-size-fits-all’ comprehensive or tested solution, it
rather explores a combination of solutions adapted to different parts of the island.
The following Sections are presented in this Report:
Section 1 – Introduction: overview of the olive oil industry, olive waste challenges, impacts and
opportunities of Lesvos Island’
Section 2 – Methodology: overview of the approach adopted in developing the Problem Statement
and answering the Research Question;
Section 3 – Olive Oil Production: overview of the global olive oil industry, specific terminology,
production and impacts regarding olive waste management;
Section 4 – Environmental Challenges: overview of the impacts resulting from lack of effective
olive mill waste management regarding water, soil and air assets;

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Section 5 – Environmental Impacts of Olive Oil By-products
Section 6 – Legislation: overview of EU and national level legislation and framework supporting
OMW management;
Section 7 – Situational Analaysis on Levos: overview of wastestreams, proportions, management
options and site locations;
Section 8 – Social Context Analysis: overview of the Island’s social characteristics based on key
stakeholder interviews, key insights and implications;
Section 9- Case Study: Facts that Enabled Spain to Treatment OMW
Section 10 – Feasibility of Treatment Options; overview of the solutions to treating OMW and
the process of elimination in filtering to suitable solutions for Lesvos;
Section 11 – Feasibility of Implementation
Section 12 – Recommendations; list of suggested actions contributing to responsible OMWT and
broader benefits to the Island through the lens of best and worst case scenarios;
Section 13 – Conclusion; critical summary of final comments regarding the opportunity for Lesvos
to transition to more effective OMW management;
Section 14 – References
Section 15 – Personal Communications
Section 16 – Appendices

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2 METHODOLOGY
The purpose of this assignment is to find a solution, or set of solutions, suitable for
transitioning Lesvos to better treat and/or utilize, olive mill byproducts. The type of methodology
adopted is therefore one of ‘problem solving’. Both quantitative and qualitative research methods were
applied to better understand the current context, challenges, impacts and potential solutions. The entire
process conducted by the Industry and Waste Group (IWG) is diagrammatically represented by Figure
6. However, key steps included the following four focal points:
1. Literature Review;
2. Data Analysis;
3. Interviews; and
4. Develop Maps: Arc GIS.
In addition to this, the IWG identified and assessed inherent flaws, constraints and limitations
with both the body of work being reviewed and the development of feasible solutions from this.
2.1 Literature Review
A Literature review was immediately carried out and based on:
a) Moodle document download and familiarization – the University of Aegean’s website
featured an extensive range of documents, data, maps and scientific articles under the
‘Industry & Waste Group’ heading. Some of these are featured in Figure 5.
b) Desktop review – a broader search was conducted for additional relevant material available
in the public arena and online. This included a range of reports, journals, meeting minutes
from the Regional Land use Council, media articles and websites.
A review of the existing literature at a global, regional, national and local scale was undertaken
to establish current challenges and approaches towards OMWM. This provided both a more
comprehensive understanding of the issue allowing the IWG to understand possible solutions around
the world; in addition to identifying key gaps in the available literature. Extensive literature regarding
the social aspects of Island communities responding to OMW, as well as the legislative framework of
Greece with respect to the EU regulations, and for Lesvos in specific was challenging to source, with
some available literature being translated by the IWGs Greek colleague. Key literature therefore
adopted for this study includes available documents from Moodle as well as those documents

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supported by the European Commission For a full list of literature sourced to support this Report,
please see the Section called References.
2.2 Data Analysis
Data sourcing largely focused on quantitative research: mills (sizes, locations, capacities,
production and discharges), waste streams (industrial, urban, olive mill specific), location of
infrastructure (WWTW and other industries), and geographic focus (waterways, bays, elevation).
Additional data was sourced online during the desktop review to facilitate data manipulation: to
support gap filling, to verify ‘suspect’ or outdated data, and to support calculations. Graphs were then
generated to diagrammatically represent the findings.
Figure 5: Literature, Aegean University Moodle Site.

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2.3 Interviews
In order to gather a more in-depth and critical understanding of the social dynamics existing
among key stakeholders involved in the olive oil industry on the Island, qualitative research was
employed through face-to-face interviews. Specific steps included:
a) Reviewing existing literature to gain social insights into the current context and key
stakeholders regarding OMW on Lesvos Island;
b) Working with Mr. Dirk Schaelicke, University of Aegean to identify specific stakeholders
the University had a relationship with and to organize interview times;
c) Establishing objectives to guide the type of specific information able to be gained from a
short interview;
d) Developing set, open-ended questions of 10 to 15 in length (equivalent to roughly 45
minutes to 1.5 hours (depending on the response of each stakeholder);
e) Working Mr. Christos Paterakis, Master’s candidate at the University of Aegean, for
linguistic support to translate the four questionnaires;
STEP 1: Situational Analysis
STEP 2: Field Trip Observations
STEP 3: Interviews & Social Analysis
STEP 4: Lesvos Island OMWM Options
- Desktop Review (All)
- Data analysis, GIS Maps & Graphs (Mile, Chris, Krithi)
- Interview Logistics and Questions (Mel & Chris)
- Global Case Studies & Options (Laurin, Laura, Krithi)
- Relevant EU & National Policies (Lucy)
- Global Scenarios of Olive Oil Industry (Tony)
- Onsite Three-Phase Olive Mill
- Onsite Feta Plant and whey management
- Product process & waste stream/byproduct observations
- 4 x Stakeholder Interviews: Mill Owners, Regional
Government, Pomace Entrepreneur
- Positions of stakeholders & implications
STEP 6: Suitable OMWM Options
- Evaluating options for management solutions
- Conduct mapping & apply evaluation
- Context of social, political and economic aspects paired
with final suitable options
- Rationale & constraints justified
Methodology
STEP 5: Evaluating Options
- Investigate island-wide viable waste management
options weighing up pros and cons
Figure 6: Methodological Process Supporting Workflow.

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f) Confirming and conducting interviews;
g) Cross -referencing understanding of responses from IWG team members who attended
the interviews (post-interview);
h) Writing-up and analyzing interview notes;
i) Integrating notes into the Report.
Selected and interviewed stakeholders included:
1. Mr. Tsanetos Manolis, Manager Olive Pellet Plant, Lambous Milous;
2. Ms. Maria Kanellos, Co-Manager, Kanellos Company, Alyfanta;
3. Mr. Bill Kokkinoforos, Manager, Mytilini Olive Oil, Moria; and
4. Ms. Martha Atsikmpasi, Head of Development Directorate, Department of Industry,
Energy and Natural Resources, Region of North Aegean.
Results from the interviews have been integrated into this Report and are largely available
under the Section of Social Context Analysis. Each stakeholder provided essential information adding
to insights on social structures and dynamics both across Lesvos and more specifically in relation to
the OMW problem. The range of responses provided clearly defined opinions that helped feed into
the simple PESTLE analysis conducted and shown in Figure 4. In essence these interviews were critical
in teasing out some of the social patterns, barriers and opportunities in transitioning the olive
community towards considering take-up of more responsible OMWM. Following the interviews the
key take-away showed that technological, economic and even legal barriers are insignificant compared
to social resistance to change. Reasons supporting this are explained throughout this Report.
2.4 Spatial analysis using ArcGIS
A series of maps using software ArcGIS, were developed for this Report. Through this
approach, the IWG was better able to visualize the currently operating 54 olive mills with associated
OMW quantities on the Island. The maps therefore were essential in displaying the current situation
to allow deeper and more thoughtful analysis to develop solutions. The final maps include: olive mill
distribution, olive mills with the potential to change to two-phase, two-phase olive mills with roads
and quantity of pomace, suitable areas for siting pre-treatment units, potential irrigation utilization,
olive mills, waterways and other key industries, and other changing mills. All maps are displayed under
the Sections Situational Analysis and Feasibility of Treatment Options.

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2.5 Constraints and Limitations
Constraints and limitations impacted the quality of this Report in terms of a comprehensive
and optimal response to the Research Question. However, the IWG recognized outdated data and
information impacted a more integrated and effective analysis. Key constraints and limitations
included:
 No one-size-fits-all – in approaching the assignment the IWG was informed that Lesvos has
tried unsuccessfully to implement some demonstration projects. Information throughout the
literature also suggested there is no ‘one’ solution to OMW and many that exist are ineffective
and expensive to pursue. The limitation of finding actively working solutions that could be
transferred to the unique situation of Lesvos was understood from the outset;
 Out of season – the assignment and Report was researched during the Olive industry’s off-
season. It was therefore limiting in terms of observing mill operations and meeting more active
stakeholders, in addition to potentially observing OMW discharges (including observing water
discoloration and odor);
 Time allocated for the exercise – a short and intense work period restricted the development
of a more comprehensive research exercise;
 Lack of prior knowledge and a steep learning curve – lack of Greek language skills (Mr.
Christos Paterakis, the IWG team member did provide critical support, however much
information and particularly all interviews, was only available in Greek); the Greek and Lesvos
culture; and technical knowledge of OWM;
 Available and accessible data – certain data inconsistencies and gaps were unable to be
resolved either because such information was unavailable, available in Greek, or incorrectly
noted;
 Interviews – although these provided essential social insights, interviews were not random,
nor representative, but rather opinions of four individuals. In terms of attending interviews
and analyzing the interview responses, not all IWG members could attend nor understand the
interviews, hence the opportunity to dialogue the results was limited;
 Assumptions – initial assumptions based on technological, legal and economic barriers proved
less significant. Social barriers were revealed towards the end of the interview period to be a
key reason for lack of OMWM on Lesvos Island. Social dynamics require a deeper
understanding to enable solutions focused research.

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3 OLIVE OIL PRODUCTION
3.1 Global Olive Oil Industry
The Olea europaea, better known as the olive fruit is a traditional tree crop of the Mediterranean
basin and the Middle East, with earliest records suggesting olives were turned into olive oil around
6000 BC (Schuster 2014). Olive cultivation is widespread throughout the Mediterranean and is of
critical importance for the rural economy, local heritage and environment. Today, the olive tree is being
cultivated in as far removed nations as: Australia, Japan and China, as well as parts of Africa. There are
more than 850 million productive olive trees worldwide, occupying a surface area of 8,514,300 ha
(FAOSTAT 2015). In 2009, a total of 2,911,115 tonnes of olive oil was produced (FAOSTAT 2015).
The olive oil industry from the Mediterranean Basin and Middle East provide 99% (Alfano et
al. 2007) of global olive production, with Spain leading, followed by Italy and then Greece. The biggest
export markets include the nations of: USA, Brazil, Australia, Japan, Russia and China (EC 2012).
3.2 Olive Oil Industry in Greece
Greece has 840,000 olive producers contributing 19.7% of the EU’s olive oil production,
equivalent to 405,600 tonnes. This is harvested from 765,000 ha of productive trees and sent to 2,786
olive mills – of which 70% are three-phased processing mills (EC 2012). Greece is famed for its ‘yellow’
color of olive oil, compared to ‘green’ colored olive oils as found predominantly in other major
suppliers such as Spain and Italy. In addition, in Greece, the share of the family work force in costs is
very high, indicating both a high number of very small family farms and the lack of
marketing/professional guidance. In this Member State, olive oil farms are characterized by a
significant increase in margins and income indicators over the 2000-05 period but by an inverse trend
from 2005 to 2009. In comparison to other types of holdings, income trends for olive oil farms were
the worst for the period 2005 to 2009 (EC 2012).
3.3 Production of Olive Oil
Olive oil production is carried out in mills and the extraction of the oil is either done through
traditional pressing (discontinuous process) or centrifuging (continuous process). The continuous
process is most prevalent today due to its positive impacts on production volume, minimization of
labor costs, smaller space requirements, better oil quality, improved process control and ease in
automation. Two technologies are established for performing the continuous process: three-phase and
two-phase processing (Azbar et al. 2004). Both technologies will be briefly described in the following.

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3.4 Three-Phase Processing
The three-phase method of processing olive oil, used on Lesvos Island at all 54 mills, first
requires the washing of olives and grinding them with hammers or stainless disks. The paste produced
is sent to a horizontal centrifuge that, with the addition of significant amounts of water, produces three
separate phases which are oil, vegetable water (OMWW) and OMP (RAC/CP 2000).
The OMWW has strong odor, and is a black and highly polluting liquid which requires
treatment before being released in the environment. The characteristics of OMWW are described more
detailed in section 4 along with its impacts on the environment.
3.5 Two-Phase Processing
Two-phase processing came on the back of the three-phase method generating large quantities
of OMWW. Vastly used at olive mills in Spain since 1992, the two-phase process for olive production
is now seen as the more environmentally friendly production process due to less water consumption
and minimal wastewater generation (Prosodol 2012).
The two-phase process starts same as the three phase extraction: washing the olives, crushing
and grinding to create a paste. After this, the processes differentiate considering the decanter that is
used (Schaelicke 2012).
Decanters of two-phase production do not require the insertion of water after grinding. It
saves not only water but also energy, since the three-phase process inserts preheated water to the
decanter. While at the three-phase process the oil is treated only in horizontal decanters, the two-phase
requires a further process of centrifuging in a vertical centrifuge to purify the oil (Schaelicke 2012).
While the three-phase process has the disadvantage of producing large amounts of OMWW
and OMP, the output of the two-phase process is a larger quantity of moist OMP. Depending on the
utilization approach for OMP, this may requires another input of energy to have it dried. Therefore,
the energy that was saved at the extraction level may be transferred to treat the residues.
3.6 Terminology: Waste and Byproducts
Since both continuous processing technologies for olive oil extraction also produce substances
next to olive oil, it is essential for further treatment and utilization to determine whether these
substances need to be considered as waste or by-products. The EC Directive 2008/98 stipulates the
need to specifically clarify the distinction between waste and by-products notwithstanding confusion
remains (Taccogna 2010). Pursuant to Directive 2008/98/EC, a by-product is the object or substance
from a production process albeit the primary aim is not the production of that object or substance. If
such an item can fulfil the following conditions, it can be regarded as not being waste (Prosodol 2012):

20
 The substance or object can be legally further used;
 The further use of the substance or object is direct without further processing except
normal industrial practice;
 The production of the substance or object is an integral part; and
 The substance or object achieves all relevant requirements on product, environment
and health for particular use and will not result in negative environmental and health
impacts in general.
In addition, a following particular “Committee Procedure” has been provided in the Directive
to clarify the conditions and technical criteria in detail. The EC Commission is entitled to “adopt
measures to determine the criteria to be met for specific substances or objects to be regarded as a by-
product and not as waste” (Figure 7).
Kontos D. T. 1997
Olive mill Waste Waters (OMWW);
Virgin Olive Pomace (OP), by pressure mills (OPP), with around 30% moisture; by centrifugal
"three phases" mills (OP3), with around 50% moisture; or by centrifugal "two phases" mills (OP2),
with moisture more than 60%, and Solid Defatted Pomace (SDP), the byproduct of the extraction by
pomace industry with solvents of the residual oil from virgin pomace (Toscano and Montemurro
2012); crude olive oil cake, obtained by mechanical extraction and contains residual oil and stones;
exhausted or defatted olive oil cake, obtained by mechanical and solvent extraction and
contains stones and less residual oil than the previous one; olive oil pulp, obtained by mechanical
extraction and stone removal; exhausted olive oil pulp, after stone removal and solvent extraction;
Olive oil vegetation water (“black water” or alpechin), obtained by centrifugation or
sedimentation of the oil, which is black and sirupy with a distinctive odour (Alcaide et al. 2008).

21
Figure 7: A decision tree for waste versus by-product

22
4 ENVIRONMENTAL CHALLENGES
The production of olive oil results in the generation of by-products. As indicated in the
previous section, the type of olive processing determines which by-products will be produced. On the
one hand, three-phase processing as prevalent on Lesvos results in OMWW as well as semi-solid OMP
production. On the other hand, two-phase processing results only in the generation of OMP with
comparatively high moisture content (Prosodol 2012). Both by-products contain several components
that can cause adverse effects on the environment if disposed without prior adequate treatment.
4.1 Olive Mill Wastewater (OMWW)
OMWW results from three-phase processing and consist of various substances that are
potentially harmful for different spheres of the environment. It is characterized by a high degree of
organic pollution due to high chemical oxygen demand (COD values up to 220g/L) and biological
oxygen demand (BOD values up to 170g/L). Hence, the COD/BOD ratio makes the OMWW hardly
degradable (Demerche et al. 2013; Tsagaraki et al. 2007). Likewise, a high content of polyphenols (up
to 80 g/L) prevents OMWW to be easily biodegradable and causes its toxicity for many
microorganisms (Tsagaraki et al. 2007). Moreover, OMWW has a low pH value between 3 and 5.9, a
high content of solid matter (up to 20 g/L) as well as significant amounts of reduced sugars and high
phosphorus and potassium content. Many of these components can result in physiological alterations
at the organism as well as at cellular levels of species (Danellakis et al. 2011). The specific
concentrations of these different components in OMWW depends on various factors such as type of
olive processed, how immediately olives are processed after harvesting, and type of production process
(Tsagaraki et al. 2007).
Therefore, the release of untreated wastewater into watercourses, as it is prevalent on Lesvos,
causes negative environmental impacts for aquatic ecosystems such as surface freshwater in rivers and
lakes, groundwater, seashores and the open sea (Tsagaraki et al. 2007).
4.2 Olive Mill Pomace (OMP)
OMP results as a semi-solid by-product from two-phase as well as three-phase processing as a
dark granular material comprising the olive seed, skin and residues. It consists of similar chemical
components like OMWW and hence is especially characterized by a low pH level, very high content
of organic matter and carbon, high levels of potassium, intermediate levels of nitrogen and usually also
contains phenolic and lipids compounds. In contrast to OMWW, OMP contains low levels of

23
phosphorus (Gómez-Muñoz et al. 2012). Figure 8 presents a comparison of some OMP characteristics
generated from two-phase and three-phase processing. A decisive difference is the higher moisture
and phenols content of OMP resulting from 2-phase processing.
Parameter Mediterranean 2-phase Mediterranean 3-phase
Moisture% 54 – 57 45 – 50
Phenols% 2.5 – 2.7 0.35 – 0.37
Total nitrogen% 0.43 – 0.48 0.50 – 0.90
Total carbon% 25 – 29 29 – 32
C/N ratio 59 – 60 57 – 59
Figure 8: Comparison of some OMP characteristics generated from 2-phase and 3-phase oil extraction
processes (adapted from Nair and Markham 2008)

24
5 ENVIRONMENTAL IMPACTS OF OLIVE OIL BY-PRODUCTS
5.1 Impacts of OMWW disposal on the aquatic environment
Olive mill wastewater is currently the major waste product of olive oil production on Lesvos
and is mostly deposed into the environment (Schaelicke 2015). The wastewater is either directly
released into the marine environment or reaches the open sea by rivers in a diluted form. Hence, it is
essential to investigate whether untreated wastewater can have adverse effects on the marine
environment.
So far, there are no studies accomplished about the negative environmental impacts of
OMWW on aquatic systems around Lesvos. Generally, the release of untreated OMWW in water
systems causes a prompt rise of microorganisms that consume large amounts of available dissolved
oxygen and therefore reduce its availability for other organisms. This may destroy the ecological
balance of an ecosystem (Camarsa et al. 2010). Likewise, the presence of high phosphorus content in
OMWW can lead to the growth of algae species and hence to eutrophication of aquatic systems. Again,
the ecological balance of groundwater and surface water can be demolished. Moreover, phosphorus
provides ground for pathogens to multiply and infect waters (Camarsa et al. 2010; Tsagaraki et al.
2007).
More specifically, results from Danellakis et al. (2011) indicate that olive mill wastewater
induces toxic effects in tissues of an examined invertebrate species. Impacts on the mussel species
Mytilus galloprovincialis were investigated as the species´ physiology is well known and it responds
promptly to environmental changes, hence making it a suitable bio-indicator of environmental
pollution in coastal waters. The study shows that olive mill wastewater induces cytotoxic, oxidative,
neurotoxic and genotoxic effects in tissues of mussels (Danellakis et al. 2011).
Further research provides evidence that aquatic organisms such as the river fish Gambusia affinis
and some crustaceans become intoxicated at very low exposure rates of untreated OMWW (Tsagaraki
et al. 2007). Likewise, research of Pavlidou et al. (2014) in Messinia, Greece, being a major olive oil
producing region in Europe, confirms that the disposal of untreated OMWW in watercourses alters
the chemical composition of freshwater as well as coastal waters. Negative impacts on a shrimp species
were detected which proves OMWW´s high toxicity in the aquatic environment. Furthermore, they
found that the riverine ecosystems needs a recovery period of more than 5 months (Pavlidou et al.
2014).

25
Finally, lipids within OMWW generate an impenetrable film on the surface of watercourses
that impedes sunlight and oxygen entrance as sources for microorganisms. This may have adverse
effects on plant growth in riverbank soils and may lead to soil erosion (Camarsa et al. 2010).
5.2 Impacts of OMWW disposal on soil
The dispersion of untreated OMWW on soil can have adverse effects on its properties and
functionalities as well as on growing plants since OMWW contains polyphenols and organic acids that
are not easily biodegradable and have phytotoxic and antimicrobial impacts. The germination of seeds,
early plant growth and the formation of leaves and fruits may hence be inhibited for different types of
plants and crops (Barbera et al. 2013; Camarsa et al. 2010; Tsagaraki et al. 2007). Heavy soils such as
clay are prone to the accumulated salts in OMWW which may lead to the collapse of soil structure
(Barbera et al. 2013). Moreover, the high levels of potassium and organic acids alter the cation exchange
capacity of the soil and hence alter environmental conditions for microorganisms. As a result, soil
fertility and soil porosity can be deteriorated. Likewise, many studies agree that OMWW reduces
hydraulic conductivity and infiltration of soils (Barbera et al. 2013). Also, the composition of OMWW
may lead to the immobilization of nitrogen and may decrease the availability of magnesium (Tsagaraki
et al. 2007). Finally, OMWW may also contaminate groundwater through leaching (Camarsa et al.
2010).
On the other hand, OMWW can have beneficial impacts when dispersed on the ground since
its metabolization to humid material by insects and microorganisms could lead to soil enrichment due
to the availability of before mentioned nutrients (Barbera et al. 2013; Tsagaraki et al. 2007). This
potential of olive mill waste components can be utilized through composting and subsequent
fertilization of soil as presented later in Section 10.
5.3 Impacts of OMWW on air
The disposal or storing of OMWW may also lead to air pollution since it can undergo
fermentation processes, resulting in methane and hydrogen sulfide formation. This is also why
OMWW is often characterized by strong odor which suggests to construct evaporation and
sedimentation ponds not close to inhabited regions or tourist sites (Demerche et al. 2013; Tsagaraki et
al. 2007).
5.4 Environmental impacts of Olive Mill Pomace (OMP)
Various research studies detected that the phytotoxic and antimicrobial characteristics of
untreated OMP affect nitrification in the soil and inhibit the germination of seeds of different plant

26
species. The high carbon-nitrogen ratio and low pH in the OMP immobilize nitrogen in the soil (Nair
and Markham 2008). Similar to OMWW, OMP also adversely affects the cation exchange capacity of
soils, hence reducing soil fertility (Prosodol 2012). These findings suggest that the application of
untreated OMP on soils evokes negative environmental implications and hence may also reduce the
agricultural productivity of affected soils. Therefore, an effective treatment of OMP is advisable prior
to releasing it into the environment.

6 LEGISLATION
6.1 Overview of OMWW legal framework: EU, Greece and Lesvos
In general, the majority of legislative EU acts regarding waste and water are in the form of
Directives, enabling each Member State to adopt and develop national legislation to manage these
areas. Since there are no particular provisions for the management of OMWW in the Common
Agricultural Policy (REACM 2009), Member States are obliged to impose their own laws and
regulations for OMWW management. This should be aligned with EU legislative norms for waste and
water treatment and quality. To fulfil this, national water quality standards and specific emission limit
values should be set and proper enforcement of these regulations should be ensured.
6.2 The EU Legal Framework of Waste and Water
EU waste legislation has evolved and developed around challenges and problems that faced
over time (Harnnarong 2009) (Figure 9).
Tightening
environmental
controls in
industrialized
countries
•Basel Convention
Pollution-control
from waste
management
options
•Landfill Directive
•Incineration Directive
Mishandling of
waste
•the first Waste
Framework Directive
•Hazardous Waste
Directive
•Waste Shipment
Regulation
Pollution
activities control
from industial
facilities
•Integrated Pollution
Prevention and
Control (IPPC)
Directive
Promote recycling,
reuse, and
recovery over
waste disposal
•reinforced the notion
of waste hierarchy
•re-affirmed the
Polluter Pay Principle
•developed the concept
of priority waste
streams
Division of waste
towards material
recycling and
biological
treatment
•setting targets for
collection, recycling
and recovery of some
key complex waste
flows
•extended producer
responsibility (EPR)
•developed the
concept of priority
Figure 9: Evolution of EU Waste Legislation

28
The core legislation among EU legislative acts regarding waste management is the Waste
Framework Directive (2008/98/EC), which covers policies on waste oils and hazardous waste that
should be dealt with by the waste hierarchy of prevention, reuse, recycling, recovery and finally disposal
(EC 2012). Relevant rules are regulated by thr Landfill Directive (99/31/EC) regarding the final
disposal of the substance. The existing waste legislations can be summarized as follows by Figure 10
and Figure 11.
Figure 10: Relevant EU Waste Legislation
Waste Framework
Directive (2008/98/EC)
Directive
67/548/EEC
Directive 92/32/EEC
Council Directive
96/61/EC
Directive 2008/1/EC
Commission
Decision
2000/532/EC
Council Directive
75/442/EEC
Council Directive
91/689/EEC
Directive 2008/98/EC
Regulation1907/2006
Regulation 1013/2006
Council Directive
86/278/EEC
Directive 91/692/EEC
Council Directive
1999/31/EC
Council Decision
2003/33/EC
Council Directive
2000/76/EC
Landfill Directive
(99/31/EC)

29
Figure 11: EU Legal Framework on Waste
The Water Framework Directive 2000/60/EC, as the EU legislation on water management,
aims to preserve water quality and achieve an appropriate ecological and chemical status. The onus is
placed upon Member States to develop strategic plans and implement management for their water
resources. In particular, the Urban Waste Water Treatment Directive 91/271/EEC concerns the
discharge of wastewater from specific industrial sectors including OMWW only after treatment, in line
with relevant standards and provisions required by the Directive (Kapellakis et al. 2008). EU legislation
on water is presented as follows in Figure 12.
Framework
Legislation
•Waste Framework Directive
•Hazardous Waste Directive
•Waste Shipment Regulation
Legislation on
waste
treatment
operation
•Waste Incineration Directive
•Landfill Directive
Legislation on
specific waste
streams
•Waste oil, titanium dioxide, sewage sludge, PCBs and PCTs, batteries and
accumulattors, packaging wastes, end-of-life vehicles, waste electronic and
electrical equipment (WEEE), Restriction of Hazardous Substances (RoHS),
mining wastes

30
Figure 12: EU Legislation on Water
6.3 Implications of the EU Policy for Greek National Legislation
As part of the European Union, the EU Directives have oriented legal framework for
sustainable waste management in Greece. Yet, this has not been fully explored in the Greek context.
Major EU Directives have been transposed to the Greek national legislation notwithstanding, the level
of implementation in Greece is still lagging behind especially regarding waste prevention and recycling
(Harnnarong 2009). This is due to the large amount of ingrained practice of uncontrolled dumping
that are difficult to behaviourally correct overnight. Further compunding this problem is the limited
geographical distribution of collective systems on the Island. In 1988, for instance, it was reported that
there were 50 uncontrolled dumpsites on the Island, which have been gradually closed and restored
since the EU Directive and fines on dumping came into effect.
Water Framework
Directive
(2000/60/EC)
Council Directive
75/440/EEC
Council Directive
79/869/EEC
Council Directive
81/855/EEC
Council Regulation
807/2003/EC
Council Directive
76/160/EEC
Regulation
1882/2003/EC
Regulation 807/2003/EC
Council Directive
76/464/EEC
Council Directive
82/176/EEC
Council Directive
83/513/EEC
Council Directive
84/156/EEC
Council Directive
84/491/EEC
Council Directive
86/280/EEC
Urban Waste Water
Treatment Directive
91/271/EEC
Groundwater
Directive
2006/118/EC

31
There are long-standing policies and particular regulations absent in Greece regarding OMWW
management (EC 2012). The principles of OMWW are based on the Law 1650/86 and 3010/2002
“For the Protection of the Environment”. This requires the local owners to conduct an environmental
impact assessment and prevent direct discharge of untreated olive mill waste to soil surface (EC 2012).
In addition, the recent Joint Ministerial Decision (KYA) 145116/2011, regulates the multi-purpose
reuse of treated water, with the use of biological treatment and disinfection units as the minimum
requirements (see Figure 13 below).
Figure 13: Greek National Legislation on OMWW
6.4 OMWW Management Policy and Planning, Lesvos Island
Lesvos Island is responsible for adopting specific olive mill management practices and setting
wastewater limits at a regional level (EC 2006). The guidance of limits was set by the specific Law
1180/1981 (see Table 1), which focused on discharge from oil production and treatment. The
implementation and final issue of limits for wastewater discharging are depended on the prefectural
authority according to the location of the specific water recipient (Papadakis 2006).
Table 1: Wastewater Limits by Law - 1180/1981
Law
1650/86
“For the
protection of
the Environment”
The circular letter
YM/578/23-1-1992
Joint Ministerial Decision (KYA)
145116/2011
 Olive mills obliged to
provide an EIA
 Efficient waste pre-
treatment
 Avoid disposal to
various water resources
 Regulates reuse of
treated wastewater for
several purposes, i.e.
irrigation

32
Features of Treated
Waste (Kg)
Maximum Value Monthly Average
pH 6-9 6-9
BOD5 4,00 2,00
COD 6,00 3,00
Suspended solids 5,00 2,00
Fats and oils 1,00 0,50
Phenols Total As required by the applicable
current legislation
As required by the applicable
current legislation
According to the Common Ministerial Decision (Φ15/4187/266/ΦΕΚ 1275Β/11-4-2012), all
treated wastewater discharged into surface water (streams, rivers, sea) by olive mills in Lesvos should
achieve the above-mentioned limits. The regional authorities are empowered to impose specific terms
to the olive mill operation (decision 2012), to enforce compliance.

33
7 SITUATION ANALYSIS ON LESVOS
Historically there has been very little waste management of any kind on the island. In the last
twenty-years this has started to change. The Municipality of Lesvos commenced recycling and solid
waste management by establishing much-needed infrastructure, such as a sanitary landfill (Schaelicke
pers. comm. b). In addition and more recently, increasing EU regulation is impacting national
environmental protection laws, and as a consequence more changes are afoot. This Section provides
and overview of current wastestreams, siting of infrastructure and management.
7.1 Overview of Wastestreams, Industries and Practises
The following section conveys the current context of both solid and liquid waste in Lesvos
including: characteristics, production and disposal. The relevance of such data is to:
a) evidence current status of the waste management on the island and to outline problems,
and at the same time; and
b) begin to analyze how this context might be managed more responsibly given current island
geographic and industrial proximity, waste quantity and infrastructural knowledge.
Impacts are discussed in Section 8 and solutions in Section 10.
7.2 Municipal Solid Waste
The population of Lesvos Island is 86,436 (Schaelicke pers. comm. b). According to the latest
Greek legislation (Spilanis pers. comm.), the whole Island is one single municipality with several
municipal units comprised from municipal communities. The largest municipal unit is the City of
Mytilini with a population of 37,890 (Schaelicke pers. comm. b), with further data showing us that the
population is largely permanent as opposed to transient or seasonal.
7.3 Production of Urban Solid Waste
The average municipal solid waste production per capita per day is around 0,98 kg (Schaelicke
pers. comm. b). This number includes both municipal solid waste as well as industrial waste. The total
waste generation per year is around 165,160 tonnes.

34
Figure 14: Total Waste Profile, Lesvos. Schaelicke pers. comm. b.
Figure 14 above shows waste streams on Lesvos Island and clearly depicts agriculture and
animal husbandry as the main activities – this results in a large amount of organic waste both from
the process of food production and animal effluent.
Figure 15: Urban Solid Waste Profile, Lesvos. Schaelicke pers. comm. b.

35
Figure 16: Urban Solid Waste Profile in Greece. Schaelicke pers. comm. b.
The comparison of composition of urban solid waste profiles between Greece and Lesvos
shows similar patterns. The largest share is composed of food waste, or as is it labeled in the case of
Lesvos, fermentable waste. The second largest proportion is paper with an identical share in total
waste compostion. This suggests that urban solid waste management practices from the mainland can
also be implemented on Lesvos. Furthermore, it shows that there are no issues related to the urban
solid waste that is specific to Lesvos Island.
7.4 Disposal
Disposal of all urban solid waste on Lesvos Island is carried out at a single location - a new
sanitary landfill with a total surface of 30,7 ha. From this 7,7 ha is for Municipal Solid Waste (MSW)
disposal and 7,5 ha is for inert waste disposal. Inert waste is that which will: not decompose, where
there is no risk of leakage to the ground, where there are no emissions to the air, or where there are
no potentially harmful substances. The total volume for MSW disposal is around 700,000 m3
(Schaelicke pers. comm. b.). However, the new sanitary landfill has been in service for only few years.
Prior to the construction of the new centralized landfill, many local landfills and uncontrolled
dumpsites were used. Figure 17 below shows both the new centralized sanitary landfill in addition to
previous landfills. Some of the previously used landfills are under the process of remediation, i.e. they
are being secured to prevent possible harmful environmental and human health impacts.

36
Figure 17: Current and Previous Landfill Sites, Lesvos. Kontos D. T. 1997

37
7.5 Industrial Waste Proportionate to Total Waste Production
Beyond urban solid waste, a significant part of the total wastestream can be desribed as
industrial waste. This waste is coming from key industries on the Island and excludes waste from olive
processing. Other significant industries include: poultry houses, slaughterhouses, distilleries and dairy
units. Current industrial waste production is around 13,500 tonnes per year. However, 98% of this
figure is derived from poultry houses and this is diverted from landfill through being reapplied to
agricultural land in the form of manure and compost for land fertilization. The waste from the poultry
houses is estimated from the number of animals filling a poultry house across a complete year. Waste
from the slaughterhouses is sent to landfill.
Figure 18: Industrial Waste Profile (exc. Olive industry). Schaelicke pers. comm. b.
7.6 Total municipal waste water
7.7 Municipal waste water production:
The per capita wastewater production on Lesvos is around 212 L/capita/day. A simple
calculation shows that the annual discharge of municipal wastewater is around 6,887,820 m3
. However
this number does not include from industrial waste water.
7.8 Disposal of municipal waste water
Figure 19 below shows the official wastewater treatment plants (WWTP) on Lesvos Island.
There is no available data on the current operational status of these treatment plants. The biggest plant
Distileries
0% Slaughterhouses
2%
Poultryhouses
98%
Industrial waste

38
is in Mytilene with a capacity of 10,000 m3
per day. The two other plants are much smaller with a
capacity of around 2,000 m3
per day, with the WWTP in Molyvos having a capacity of around 3,000
m3
per day. Combined, these plants combined meet the wastewater treatment needs of around 38,550
people, or 44,5 % of the total population of Lesvos Island (Schaelicke pers. comm. b.).
Figure 19: WWTP Sites, Lesvos. Kontos D. T. 1997
The technology used in these WWTP’s (e.g. Mytilene) is extended aeration without primary
settlement and biological phosphorus and nitrogen removal.
7.9 Industrial waste water as a part of the total waste water
As in the case of solid waste production, industries on the island are also producing significant
amounts of wastewater. The estimation of total wastewater production derived from the industrial
sector is around 108,000 m3
per year (Schaelicke pers. comm. b). However, this estimation is quite
speculative. For instance, olive mill wastewater discharge is calculated as an average of a two-year
production (biennial cycles). In case of diary units, an estimation of excess whey as well as waste water,
is taken into account. The waste water is estimated based on an estimation that processing of 1 t of
milk will produce 1m3
of the wastewater. Furthermore, it is important to mention that all poultry

39
houses apply primary treatment of wastewater, in addition to some diary units. Olive mils, apart from
a few exceptions, do not have any kind of pre-treatment on site; none of these units are functional.
Figure 20: Total Wastewater Production Profile, Lesvos. Schaelicke pers. comm. b.
Figure 21 below shows diary unit locations along with the locations of differently sized olive
mills. The purpose of this figure is to stress geographic proximity – both between the industries and
in relation to the Island’s watercourses. As there is a lack of WWTPs and onsite pre-treatment, high
organic loads would be discharged almost directly to these watercourses presumably stressing the
environment. Given the locations of these industries with largely organic and therefore highly
concentrated wastewater, a solution might be co-treatment with other industrial wastewater.

40
Figure 21: WWTP and Olive Mill Sites, Lesvos. Kontos D. T. 1997
7.10 Olive Oil Waste Management
As shown in Figures 22 and 23, there are currently 54 olive mills operating on Lesvos Island
of varying sizes and technical capabilities (Schaelicke pers. comm. b). The words “currently operating”
refer to ‘mills that have been operating at least one year in the last three years’. Mill size is calculated
on the basis of average weight of olive processed in the last two operating years within the last three-
year’ time-span.

41
Figure 22: Olive Mill Sites, Lesvos. Kontos D. T. 1997
Figure 23: Olive Mills by Size and Location, Lesvos. Kontos D. T. 1997
Calculations of the wastewater were based on the equation which says that, for processing
100kg of olives, 135L of wastewater will be discharged. The graphs below show total olive processes

42
as well as total wastewater discharged per year, in the last seven years. The trend of biennial olive cycle
is clear.
Figure 24: Total Kilograms of Olives Processed, Lesvos: 2007-2014. Schaelicke pers. comm. b.
Figure 25: Total OMWW production, Lesvos: 2007-2014.. Schaelicke pers. comm. b.
0
10000000
20000000
30000000
40000000
50000000
60000000
70000000
80000000
90000000
100000000
2007-2008 2008-2009 2009-2010 2010-2011 2011-2012 2012-2013 2013-2014
0
20000
40000
60000
80000
100000
120000
140000
2007-2008 2008-2009 2009-2010 2010-2011 2011-2012 2012-2012 2013-2014

43
8 SOCIAL CONTEXT ANALYSIS
Lesvos Island enjoys a unique culture and mentality as it relates to the olive oil industry.
Anecdotal feedback during this project exercise suggests this mentality may sit apart from the rest of
Greece and is characterised by a reluctance to change even in the face of possible beneficial gains
(Paterakis pers. comm.). Such anecdotes are supported by the historical inertia of the olive oil industry
in managing its liquid and solid waste, while others in Crete, Spain and Italy have progressed at large.
Furthermore, interview results support social resistance to transitioning the industry to more
responsibly manage waste products and to leapfrog into utilizing, and even marketing, niche
byproducts. There are a variety of assumed reasons for such resistance; these are steeped in governance
issues, legal expectations and social arrangements centred around small family holdings. The social
context is analysed crudely and outlined below in sections dealing with the overview of interviews, key
insights and possible implications.
8.1 Overview from Interviews
Four interviews (see Appendices 20.2 for full interview notes), were conducted with key
stakeholders to ascertain insights into the historical, current and possible future social dynamics, central
to the olive oil industry and waste management options on Lesvos Island. Interviewees, their roles and
industry positions are described below in Table 2.
Table 2: Stakeholder Interviewees, Roles and Industry Positions
INTERVIEWEE ROLE INDUSTRY POSITION
1. Mr. Tsanetos Manolis,
Manager Olive Pellet Plant,
Lambous Milous
Pomace Factory
The first out of three pomace
factories to be equipped to
manage two-phase approach.
Processes three-phased
pomace with saleable
byproducts of: pomace oil,
pomace biomass, pomace
pellets and compost.
OMW Entrepreneur
Established factory to take the
first-mover advantage to
process two-phased pomace
and market byproducts
domestically and
internationally. Believes the
Lesvos Island market is viable
but sees social change
hindered by tradition and lack
of collective vision, as key

44
barriers.
2. Ms. Maria Kanellos, Co-
Manager, Kanellos
Company,Alyfanta
Olive Mill Owner
Family run mill formerly
treated wastewater through
holding tanks and lime, no
longer applies lime treatment.
Waste water released to the
sea.
Olive Oil Producer
Believes law will eventually
insist on transition. Will apply
the installed two-phased
decanter when forced. Has no
solution to wastewater.
3. Mr. Bill Kokkinoforos,
Manager, Mytilini Olive Oil,
Moria
Olive Mill Owner
Family run mill. No
wastewater treatment. Waste
water released to the sea.
Olive Oil Producer
Believes the 300-year practice
is organic and does not
negatively impact the
environment. No evidence
supports any negative impacts.
Would consider using a two-
phased decanter if the
authorities demonstrated cost-
effective solutions.
4. Ms. Martha Atsikmpasi,
Head of Development
Directorate, Department of
Industry, Energy and Natural
Resources, Region of North
Aegean.
Government Authority
Formerly worked under the
Prefecture level. Large
restructuring has resulted in a
change of governance and
procedures. Former
noncompliance OMWM
loopholes are now closed.
OMWW Compliance
2015 marks a new proactive
approach with 16
noncompliance fines issued
randomly across the mills.
Believe some concessions such
as reduced BOD loading limits
can be made in exchange for
Mill Owners implementing
some form of on-site OMWM.
8.2 Key Insights
Interviewees were directly approached as opposed to randomly selected, and were limited to
four stakeholders in total as opposed to representatively sampled. Nonetheless significant information
was volunteered by each interviewee that adequately paints a picture of the social context and
complexity of relationships between government agencies, mill owners and pomace factory owners.
Key insights gleaned from the four stakeholder interviews included the following:

45
8.3 POMACE PELLET FACTORY:
1. Viable all-year round business: The four initial investors were set to recoup their financial
returns to breakeven within a 3-year period from when the business was established. The
factory is able to almost double its production if it can get the feedstock. Research and
Development is looking to use the off-season to produce biomass to energy (heating mainly)
from artichoke crops grown on Limnus island.
2. Low waste, high byproducts: The pomace pellet factory produces little waste as most is
reused or lost in the process via biomass, evaporation, water recirculation, packaged
byproducts of oil and pellets, and on-site composting. Four of the five byproducts are
repackaged into containers and sold to both domestic and international markets.
3. National waste laws act as barrier: Pomace oil once extracted from the process is prevented
from being sold on the local (Greek) market by national law. The law sees extracted pomace
oil as a waste product and not fit for integration into the food industry. Instead this product is
sold to the Italian market where is mixed with other oils and used in the food industry there,
or sold back to Greece.
4. A Threat: The pomace pellet factory buys pomace at 16 euro/kg (the same rate as the other
two pomace factories) from a few private mill owners. He has had to network very hard to
secure these suppliers and believes his business is viewed as a threat by olive mills cooperatives
and the two other pomace factories. The owner’s views are based on a lack of industry inclusion
and engagement with his factory. This may be a result of Mill Owner now having no excuse to
make a switch to two-phase production as prior to the establishment and operation of the
pomace pellet factory, Mill Owners could justifiably use the rhetoric of having nowhere to take
the solid waste, and therefore this supported not making any effort to switch to two-phase
processing or consider more effective waste treatment.
5. Installing two-phase decanters: Both the Mill Owners interviewed have two-phase
decanters procured with EU funds provided under a productivity and technology enhancement
program around 2005-2009. Mill Owners decided to upgrade technology and install a two
phase decanter in anticipation of eventual regulation changes. Neither Mill Owner intend to
make the shift from three to two-phase processing until there is no choice by law.
6. Resisting change: Mill Owners are resistant to change, maintaining the understandable
rationale that they have carried out this work for hundreds of years; that this is part of their
heritage and they know what they are doing; and that the waste material is all natural and

46
organic, so not harmful to the environment. In addition, the obvious lack of locally evidenced
environmental impacts through research and monitoring OMW, continues to be used as a
justification by Mill Owners to continue to defer treatment. Mill Owners also feel if
government wants them to comply with strict regulation, then government should tell them
how - if this proves cost effective and simple to the Mill Owner, they will make the suggested
and supported changes.
REGION OF NORTH AEGEAN GOVERNMENT:
7. A Legacy of Poor Governance: Up to 2010/11, the former governance structure was at the
Prefecture level and was responsible for compliance of OMW. The Prefecture, with an Olive
Grove owner as its Head, effectively did very little to monitor Olive Mill Owners or their
OMW status. Licenses were thus approved year-on-year without compliance to national and
now EU effluent standards. A restructure in 2011 and a new Head meant scrutiny was now
being placed on OMW. However, a technical ‘loop hole’ allowed all 54 Olive Mill Owners to
continue to avoid compliance.
8. Regional Government Signals Change: In 2015, for the first time in history on the Island
of Lesvos, 16 fines have been issued to Mill Owners who have failed to comply with BOD
regulations. The Regional office has stressed it was always in favour of compliance and the law
was present, but not enforced. The fines of 500 - 1,000 euro, will be issued up to three times
to non-compliant Mill Owners with a final threat of potential closure.
9. Current EU and National Laws Too Strict: Government supports that current BOD limits
are too high, too strict and not realistic. The Regional office plans to seek a reduction -
essentially having the limits relaxed so that Olive Mill Owners have a possibility to comply.
10. Mill Owners Encouraged to “Do something”: The Regional office support Mill Owners to
implement whatever measures they can onsite to reduce waste. “Do something” will be viewed
more positively compared to do nothing. However the authorities do not have capacity to help
with any on-the-ground support, nor funding, nor do they seek to ‘compete’ with
environmental consultants that Mill Owners should hire to assist with such on-the-ground
waste management implementation.
11. Forming an Alliance: It is the belief of the Regional office that the Olive Mills and co
operatives have largely banded together in opposition to the enforcement of olive mill waste
compliance. The belief being a stronger collective group has more ability to uphold a veto.

47
However, the Regional office believes the Mills will start complying one-by-one and then
others will follow, effectively breaking the informal alliance.
8.4 Possible Implications
On analysis, the insights provided by interviewees have some serious implications, especially
as these relate to olive oil waste management. The social dynamics around the olive oil industry likely
require further social science research to better understand the motives, attitudes, and behaviours of
specific industry stakeholders in transitioning towards shared risk and reward in more responsible
practice of olive oil waste management. This might include educational exchanges from operators in
Crete for example, or program brokerage for onsite treatments, and also research, development and
marketing for byproducts of the process. As it stands the key implications include:
⇛Social Barrier: OMWM is better understood post-interviews, to be a significant social
barrier as opposed to a technological, legal or political barrier. With a legacy of non-compliance and a
lack of on-the-ground demonstrations funded by Government, there is heavy resistance to change by
Mill Owners who both lack incentives and the mentality to make a responsible transition. A social
unwillingness and inaction results in delays to take up change options.
⇛Technical Solutions: Two-phase decanters are currently available and in many cases,
already installed within the Mills. It is understood that additional investment would be required
however to fully transition the Mill to a two-phase process - in any case, technology is installed but not
yet implemented. Mill Owners already have awared of their options for treatment and have even
suggested evaporation and sedimentation to the Regional office.
⇛Stress: Biodiversity and water resources may show stress if pollution continues,
compromising flora and fauna. OMWW is released in concentrated form (being a November to March
period) with high levels of polyphenals and BOD. The ecosystem may not have the capacity to restore
itself as it has traditionally, especially with other external stresses such as climate change and increased
run-off for example.
⇛More Fines: Mill Owners who remain noncompliant will likely face more frequent fines
given the Region’s mantra to take enforcement more seriously.
⇛Legal barrier lifted: The Region of North Aegean would both assist Olive Mill Owners
initiate compliance and likely gain reputation for this, in relaxing the current BOD limits by about
40%.

48
⇛Factions may compromise a positive transition: Despite an island setting and a heritage
industry, large communication gaps remain between organisations: Mill Owners, pomace
entrepreneurs, Cooperatives and likely the Union of Cooperative, as well as the Region of Northern
Aegean institute.
⇛Customised Waste Measures Inevitable: Mill Owners will eventually implement
customised waste measures because they are likely to respond to a range of current and future signals
such as: the impetus by government, a changing network whereby one-by-one Mills comply, an
evolving industry whereby all pomace factories can adequately process two-phased waste and finally,
broader market benefits of byproducts in demand (whether these be biomass, compost or beauty
products).

49
9 CASE STUDY: FACTS THAT ENABLED SPAIN TO TREAT ITS OMW
Spain is often mentioned as a case of success regarding OMWW treatment. In fact, even to
consider the scope of this study for Lesvos Island, the method adopted by Spain has been considered
as an example to be implemented in Lesvos to solve the OMWW issue.
There are a few facts that put Spain as a benchmark for addressing fast and effectively the
problem of olive oil waste. This section aims to suggest the main aspects of Spain’s transition to better
management practices and analyse if it can be adopted to Lesvos.
9.1 Policy and Financial Aid
In 1982, a law was placed to forbid the disposal of OMWW into natural water courses or on
the soil. In order to aid the OMWW management, the government subsidized the construction of 1000
evaporation ponds off-season which improved the water quality in the river systems in Spain (Prosodol
2012). However, as evaporation ponds are infamous for its odour, Spain continued to research other
options.
The European regime for Olive oil production granted aids to 2.2 million of the 2.8 million
recorded producers of olive oil in the European Union. Of the total production aid granted (measured
by the “Maximum Guaranteed Quality” of the production) 42.8 % is allocated to Spain, 30.6 % to
Italy, and 23.6 % to Greece (Lacroix 2002). That gave Spain a financial advantage compared to other
Mediterranean producers countries to seek improvements in the olive oil production in general.
In 1992, Olive Mills of the Andalusia region were introduced to two-phase process. Soon
almost all olive mills in Spain would transfer to the two-phase process (Niaounakis and Halvadakis
2006).

50
Figure 26. Number of mills and production methods in Andalusia (IMPEL 2003)
Another policy that helped OMWT was implemented in 2002 and refers to operations of
valorisation and disposal of wastes (O.M. MIMAM 304/2002, 19 February 2002, activities of
valorisation and disposal of wastes). Spanish changed legislation to consider OMW a secondary
product that can be valorised to prevent soil and/or water contamination (Prosodol 2012).
However, the main policy that probably influenced Spain to switch to two-phase (probably
because there has not a single paper that affirms it) is the one that requires a permit for every
catchments of continental water over or under ground. Also an authorization of spill is required for all
activities that are susceptible to cause pollution or degradation of the hydraulic public network. This
law was first created in 1985, amended in 1999 and affects directly the evaporation ponds and irrigation
usage (Prosodol 2012). It is possible that bureaucracy for such permits pushed mills to adopt two-
phase systems.
9.2 Mill Geographic Distribution and Cooperation
The concentration of olive mills in the Andalusia region can also be an important explanation
of why Spain was able to effectively implement OMW treatments. About 75–80% of the average
annual production of olive oil in Spain comes from the Region of Andalusia, where are located most
of the olive-mills that operate in Spain (1700 are there) (Lacroix 2002). Besides having fewer mills by
area, they have greater production among cooperatives (Lacroix 2002), which make the investment
more worthy.
Not only Andalusia, but throughout Spain, being clustered in cooperatives helps stakeholders
communication (with researchers, government and other institutions) and promotes faster decision-

51
making when choosing types of treatment, for example. According to Cooperativas agro-alimentarias
2010, in 2009 there were 1.744 olive mills in Spain, being 951 of them cooperatives.
Figure 27. Number of workers, number of olive mills and representing percentage. (Niaounakis
and Halvadakis 2006)
9.3 Technology Advantage
The two-phase process still leaves some liquid effluent from the process and the moist pomace
is more energy demanding when compared to three-phase process. However, as Spain is the center of
attention and mills are big enough to justify investments, there has been water recycling, energy
recovery, composting and use in agriculture to compensate the disadvantages of two-phase systems.
Besides that, Spain is still pioneering research of other solutions. Below are some ongoing
projects:
 Algatec: Financed by the European Union, Algatec is a project of recycling systems to
reuse water after the washing of olives. The process uses algae and sunlight to
decontaminate wasted waters. It has been tested in a Cooperative in Córdoba, however,
the return of investment is still unachieved (Penafiel 2012).
 Olive oil power plant: the pilot project is being run in Granada and aims to address the
organic waste problem with energy creation. The technology can break down the toxic
compounds and provide enough energy to achieve 50% of the plant needs. The project
is a partnership of KTH Royal Institute of Technology in cooperation with PowerCell
AB, both Swedish, and is still being studied to become more effective and to lower
costs (Pultarova 2015).

52
10 FEASIBILITY OF TREATMENT OPTIONS
As mentioned earlier, olive mill wastewater is a cause for environmental concern and Lesvos
needs to address solutions in order to avoid pollution and to comply with regulations. Although Greece
is currently in the depth of an economic crisis, the lack of compliance with wastewater disposal
legislation poses a massive risk to environmental stability of its islands.
However, finding a single solution to the 54 mills is tricky one: each mill has different
economic, geographic, geological, elevation, transit network and water network characteristics. The
suggestion from the Spanish case study could be considered for Lesvos with certain caveats.
First, Greece has little to none financial aid from the EU when compared to Spain (Lacroix
2002). In Lesvos, at least, mills have no financial or technical support from the government (Bill pers.
comm.). Secondly, the Greek legislative system is mandated to imbibe the EU Water and Waste
Framework directives; there is, however, still a policy that treats by-products of OMWT as dangerous
oils, instead of valorisation as a by-product as exemplified by Spain in 2002.
Another point of discussion is regarding the characteristics of the olive mills. In Spain the olive
mills are geographically concentrated. They produce more olive oil individually and a vast majority of
them are Cooperative owned (Almazaras 2010). Meanwhile on Lesvos, the mills are sparse, small and
are reluctant to work collectively (Bill pers. comm.). These facts together suggest that the solution
found for Spain cannot be replicated for Lesvos directly.
Therefore, the pathways and solutions for OMWW and pomace treatments that will be
presented in the following content considers:
 The recommendation of Camarsa et al. 2010 (Figure 28) regarding more appropriate
treatments for single or a group of mills
 The reluctance of mill owners to adopt a treatment solution and their subsequent
unwillingness to change infrastructure and maintain treatment units (Bill pers. comm.)
The possibility of finding decentralized solutions for the mills in order to maintain the
distribution of income to different families and keeping olive oil quality (in comparison with centralized
solutions where revenue is concentrate and collective crushing of olives, resulting in reduction in
quality of olive oil produced) in mind, possible treatment alternatives have been explored (Figure 28)
(Kalogeropoulos et al. 2014).

53
Figure 28. Proposed treatment technologies. Source: Camarsa et al. 2010
The following section consists of a review of some of the management techniques that could
be adopted in Lesvos, considering the restraints mentioned above. Pre-treatment systems such as
evaporation or sedimentation ponds are analysed and the possibility for wastewater utilization for
irrigation is seen. Similar treatment and use options for the pomace have been considered and possible
use as compost and fuel pellets has been studied.
The scope of the review excludes a few technologies that would require more infrastructure
and maintenance. For example, below are some other treatment options for OMWW that will not be
analysed in detail in this study (however, reviewed in Appendix 20.3):
 Aerobic or anaerobic treatment
 Electrolytic control for odor
 Phytoremediation
 Biogas plants
 Ultra membrane filtration
 Wastewater network treatment

54
To sum up, the technologies for OMW for both two and three phase process that will be
analysed summed up at the table below.
Included Excluded
 Pre-treatment
o Evaporation ponds
o Liming and sedimentation
 Utilization
o Irrigation
o Composting
o Pomace to Biomass
 Treatment
o Co-treatment with urban waste
water
 Aerobic or anaerobic treatment
 Electrolytic control for odor
 Phytoremediation
 Biogas plants
 Ultra membrane filtration
 Wastewater network treatment
10.1 Pre-treatment
As seen earlier, the issue with olive mill wastewater management is not the dearth of treatment
technologies. A vast variety of treatment options have been piloted and implemented around the
world, effectively achieving the desired effluent quality. The issue on Lesvos however, is multi-
dimensional, involving the cost of treatment, political restrictions and the lack of willingness to adopt
any suggested changes. Considering these restrictions a review of the OMWW treatment literature was
conducted the following physical and physicochemical techniques were identified as possible methods
that could be implemented on the island. Although these processes do not result in the complete
treatment of the OMWW, the resultant effluent from these pre-treatment techniques are rendered fit
for land application and/or used for irrigation.
10.2 Evaporation ponds
This is one of the most basic methods used for the disposal of OMWW. The evaporation unit
is essentially a large pond or a tank that has a large enough capacity to hold OMWW generated for the
season. The design criteria for the construction of evaporation ponds as given by Kohler et.al in 1955
estimated based on lake evaporation studies. Since then, there have been multiple equations suggested
taking various criteria into consideration. The equations used for the calculation of the size of these
ponds depends on data availability and the variability of the parameters considered. The components

55
to be considered in the calculation for the dimensions of an ideal evaporation pond are temperature,
wind velocity and direction, humidity, precipitation patterns (if applicable) and radiation data.
Considering the fact that the production season for olive oil, and the subsequent production of
OMWW is a seasonal activity, and the wastewater is generated in the winter, the evaporation pond
should be designed with a capacity equivalent to the total OMWW generated in the season. Due to
these constraints, evaporation ponds usually occupy a large area of land.
During the use of the evaporation ponds, the wastewater produced from the 3 phase
processing of olive oil production is diverted to the evaporation pond and is stored there for the rest
of the season (Niaounakis and Halvadakis 2004). As a result of degradation of the organics present in
the wastewater, there is a stench that is generated from the wastewater. This is one of the greatest
criticisms of adopting this process of disposal (Rinaldi et al. 2003).
The wastewater is stored in the evaporation tank throughout the production season and is
allowed to evaporate. Due to the high retention time in the evaporation pond, the base of the pond
needs to be appropriately sealed using compacted clay and cement in order to prevent any infiltration
and groundwater contamination (Kapellakis et al. 2006). The solids in the wastewater settle at the
bottom of the tank into a thick sludge. The thermal effect results in the formation of concentrated
cakes of organic olive mill waste that can be composted and applied on the soil (Rinaldi et al. 2003).
10.3 Liming and sedimentation
One of the easiest physic-chemical treatment processes used in the pre-treatment of OMWW
is the treatment with the addition of lime, Calcium Oxide (CaO). CaO is a natural coagulant and results
in the formation of pollutant flocks upon addition to water with high metal ion and organic content
(Mitrakas et al., 1996). The flocks formed coagulate with the existing suspended solids in the OMWW
and aid settling and subsequent removal of solids from the effluent. Studies conducted revealed that
the pre-treatment of OMWW with lime followed by traditional sedimentation results in the increase
of the pH from the acidic range to a pH of 8 to 12 with a corresponding removal of 43% of phenols,
40% reduction in the chemical oxygen demand and 95% reduction in the oil and grease content of the
wastewater (Aktas et al. 2001). The application of further centrifugal separation or filtration processes
for the removal of the flocks results in polyphenol removal efficiency of 62-73% and 99.5% efficiency
in lipid removal. It has also been observed that the effluent produced as a resultant of liming has a
high biodegradability due to the presence of nutrients in the water (Beccari et al. 1999).
One of the drawbacks in implementing this technique of pre-treatment is the initial cost of
construction of the treatment unit. An ideal pre-treatment unit foe the application of liming comprises

56
of a mixing tank, where the flocculent (lime) is mixed with the waste water and a sedimentation tank.
The unit also needs to have sludge drying beds in order to dry the resultant sludge which can then be
composted and applied on land (Aktas et al.2001). Some of the other drawbacks include, initial cost of
construction, cost of lime and the cost of operation and maintenance of the plant.
Despite these drawbacks, liming is one of the most preferred techniques of OMWW treatment
as the resultant effluent is rich in nutrients and can be applied on land for irrigation, resulting in an
improvement in soils with low nutrient content (Rinaldi et al. 2003).
10.4 Utilization
The resultant effluent of wastewater treatment from the technologies selected do not comply
with the standards prescribed by the EU for the subsequent release into any water body. Thus the
closed loop option of effluent utilization has been explored in this study.
10.5 Irrigation
Under experimentation in small mills all around the Mediterranean, irrigation (or spraying) is
among the possibilities of OMWW treatment (Camarsa et al. 2010).
The process consists of pre-treatment of the OMWW, which aims to reduce the organic load
and solids quantity that significantly can reduce the odours that rise from fresh OMWW. Liming and
sedimentation can be applied, however, considering the mills size in Lesvos Island, the pre-treatment
could already present a challenge to workers.
A few studies suggest that the fresh OMWW could be directly sprayed to olive farm and there
would be no damage to soil or groundwater (Camarsa et al. 2010). The main concern of spraying
OMWW is due to the presence of polyphenols in the OMWW which have a strong phytotoxic and
antibacterial action. The studies carried out on this subject involved field and laboratory investigation.
They state that using OMWW for irrigation causes no harm to environment. On the contrary: the
OMWW contains large amounts of nutrients (potassium, nitrogen, phosphorus, calcium, magnesium,
iron) that improve soil fertility, can help compensate the high demand of water for irrigation and
enhance farms yield. In Cretan fields, after three consecutive years of research, polyphenols had higher
measurements after spraying but they decomposed rapidly enough to maintain the benefits of using
irrigation and safe groundwater (Chartzoulakis 2010). Also, in southern Italy, OMWW was sprayed on
durum wheat drops with and without pre-treatment. There had been some impacts in the beginning
of vegetative stage but durum wheat has good capability to recover (Rinaldi et al. 2003).
Besides the positive results, the use of irrigation as one option for OMWW treatment has
important and overall impediments clayey soils. OMWW increases the accumulation of salts, soil

57
structure can more easily disintegrate and cause severe erosion (Moraetis et al. 2011). Combined with
technical issues, authorities demand additional permits from the mills proving that the water is safe for
irrigation. Therefore, the adoption of irrigation with OMWW needs to be controlled not to cause
further soil damage (Chartzoulakis 2010).
10.6 Composted Olive Mill Pomace
Pomace is one of the major by-products of the olive oil production process and results from
2-phase as well as 3-phase processing. As indicated in chapter 7, the environmentally harmful
composition of pomace necessitates treatment before it can be utilized or released into the
environment. One approach for utilization of pomace after extracting its final oil content, is to
transform it into organic fertilizer and soil conditioner for agricultural purposes and hence make it also
available for the improvement of soil fertility in olive farms (Gómez-Muñoz et al. 2012).
In order to be applied as a fertilizer, pomace needs to be composted. This is a bio-chemical
degradation process of organic materials which consists of three phases: an activation phase, the
thermophilic phase during which temperature increases, and a mesophilic phase that leads to cool
down of the compost (Muktadirul Bari Chowdhury et al. 2013). The compost mixture can be treated
in aerated or non-aerated piles and different approaches for ventilation and turning of the compost
mass can be applied. It is advisable to add a blend of organic components as bulking agents to the
olive mill pomace, such as olives leaves, twigs, straw, and manure, in order to optimize porosity and
temperature in the composting process. The total composting duration can vary significantly between
a month and up to a year depending on pomace type, bulking agents, volume of the compost pile
(influenced by porosity and moisture levels), and aeration system applied (Muktadirul Bari Chowdhury
et al. 2013). The composting process reduces the high levels of liquid in olive mill pomace and hence
also reduces its volume, both is especially beneficial for the moist and voluminous pomace of 2-phase
olive oil processing. Finally, composting is a necessary bioremediation process for decreasing the
polyphenol content and for generating pathogen-free compost (reached by temperatures above 55 °C)
(Muktadirul Bari Chowdhury et al. 2013). Research demonstrates that compost derived from OMW
materials contains satisfactory final carbon-nitrogen ratios but usually lacks in total nitrogen due to low
levels of nitrogen in the initial waste materials. This can be compensated by applying manure as a co-
composting material. Sheep and poultry manure appear to be the most effective bulking agents in
terms of optimizing microbial activities (Muktadirul Bari Chowdhury et al. 2013). Altogether, research
emphasizes that characteristics of produced compost from olive mill pomace are suitable for
agricultural purposes based on the organic matter and carbon, high level of potassium, low to medium

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