Journal of Cleaner Production 12 (2004) 613621www.elsevier.com/locate/jclepro
Cleaner production implementation through process modificationsfor selected SMEs in Turkish olive oil production
S. Gurbuz, N. Kiran-Ciliz , O. YenigunInstitute of Environmental Sciences, Bogazici University, 34342 Bebek, Istanbul, Turkey
Received 14 April 2003; accepted 17 July 2003
Turkey as a Mediterranean country has suitable conditions for olive oil production. However, by-products of olive oil production(pomace and vegetation water) require specific management with the goal of pollution prevention. This paper explores the applica-bility of Cleaner Production (CP) methodology for fifteen crude olive oil extraction Small and Medium sized Enterprises (SMEs),one olive oil refining plant and one pomace oil extraction plant operating on the Aegean Sea coast of Turkey. It has been deductedthat; if the recommended CP options comprising water, energy saving issues, and pomace management options regarding energyproduction and raw material recovery via thermal conversion processes will be implemented, the need for end-of-pipe treatment(EOP) facilities will decline and power generation from pomace will be environmentally, technically and economically feasible. 2003 Elsevier Ltd. All rights reserved.
Keywords: Olive oil process; Energy; Vegetation water; Olive pomace
Olive oil is a typical Mediterranean product, in termsof production and consumption [1,2]. There are about805 million olive trees in the world, covering approxi-mately 24 million acres. Almost 98% of these trees growin the Mediterranean area which provides for 97% of thetotal olive production and 91% of world consumption. Turkey is in the top rank of fourth amongst the Med-iterranean countries as olive fruit production shows fluc-tuations on a yearly basis. Turkish olive oil productionreaches up to around 200,000 t/year during on yearsand around 80,000 t/year during off years . Turkeyplays an important role in the export market of olive oil,which forms a great majority of her production (90,000100,000 t/year). According to the International Olive OilCouncil (IOOC), Turkish exports account for 10% of thetotal world exports.
In Turkey, olive is both processed in small andmedium size enterprises (SMEs) and modern facilities
Corresponding author: Tel.: +90 212 358 1540; Fax: +90 212257 5033.
E-mail address: firstname.lastname@example.org (N. Kiran-Ciliz).
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to produce edible olive oil. Although olive oil productionhas an important economic contribution for the Europeanand Mediterranean part, it has considerably adverseeffects to the environmental welfare due to high amountsof vegetation water; and pomace; which are wastewaterand olive cake produced from olive oil extractionrespectively. Due to their high economic and environ-mental value the vegetation water and pomace obtainedfrom olive oil production processes are considered as by-products. However, The Olive Oil Producers Associationin Turkey is unable to manage these valuable by-pro-ducts. As a result of this, most of these valuable by-products are disposed without any control. Within thisframe, the maximum recovery of the by-products duringolive oil production process with the successfulimplementation of Cleaner Production (CP) method-ology for olive oil industry.
Cleaner Production (CP) is a protective and prevent-ative approach. As opposed to conventional pollutioncontrol approaches, which are known, as end of pipetreatment facilities (EOP) CP strategies aim to deal withthe problems at their source, trying to avoid their occur-rence . Regarding this concept, the paper focuses onthe application of CP methodology, for the selected oliveoil producing enterprises operating in the town Edremit
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located on the Aegean coast of Turkey. Seventeen SMEswere selected to carry out this study. The first fifteenSMEs are responsible from crude olive oil production.Later on the produced crude olive oil was sent to anotherSME for refining applications and finally the extractionof olive oil from pomace the solid residue producedby the first fifteen SMEs and its final managementwere carried out in the last SME. Location of theenterprises are illustrated in Fig. 1.
Within the scope of CP methodology; the commitmentof the enterprises were obtained during planning andorganisation phase, the CP focus points were generatedat the end of the pre-assessment phase and they wereevaluated and prioritized in assessment phase. Finallythe CP options were screened during the feasibility phasetaking into account the economic and environmentalissues.
The recommended CP options include; water andenergy saving issues through technology modification incrude olive oil extraction SMEs, and optimum pomacemanagement options via incineration, gasification andpyrolysis processes regarding energy and raw materialrecovery issues. Within this frame, in Section two of thispaper, types of crude olive oil production processes areexplained and compared briefly. Information on by-pro-ducts of olive oil production is given quantitatively. Theinputs and outputs including their costs for the wholeolive oil production chain are illustrated.
In Section three, CP assessment is realized in detail,material and energy balances at each stage of olive oilproduction are derived and evaluated. A comprehensiveset of cleaner production options are generated and listedin the order of priority.
Section four comprises the results and discussion part,which cover the feasibility phase of the CP methodology
Fig. 1. Location of enterprises
considering economic and environmental evaluation ofgenerated CP options. Pomace management options tak-ing into account the utilization of pomace as a fuel incombined heat and power (CHP) plants for in situ powergeneration in the refining plant is described.
Finally, Section five deals with the conclusionsobtained from the study.
2. Cleaner production in Turkish olive oil industry
The Mediterranean is the center of almost all inter-national olive oil marketing activities. Turkish olive oiltrees cover 4% of the overall agricultural areas in Tur-key. The olive oil production in the regions of Turkeyare 7580% in the Aegean area, 10% in the Mediter-ranean area and around 10% in the areas of Marmaraand South East Anatolia. As the Aegean coast is Tur-keys leading olive oil producer, the enterprises selectedfor the implementation of CP were in this region .
In the areas mentioned above with the exception ofTurkey the production of olive oil and the exploitationof its by-products have been properly done. For this rea-son the main goal of this study was to promote the com-mitment of the management of those firms that willinglyparticipated in this study. It was believed that by show-ing the benefits of cleaner production, firms would bemore willing to engage in innovation in cleaner pro-duction.
Gaining the commitment of firms represents a greatchallenge. This results from the fact that the productionof olive oil encompasses several firms and the adoptionof the new processes implies planning of activities inorganisational and administrative dimensions.
Olive oil in general is obtained by means of three prin-
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cipal procedures: the pressing system, the three-phasecontinuous system and the two-phase continuous system.The oldest olive oil production method, the pressing sys-tem with its low quality olive oil generation capacity,is not preferred anymore. In the three-phase continuoussystem, a horizontal centrifuge is used where processwater addition is required for the separation of the threeproducts: oil, vegetation water and pomace. In this sys-tem, due to the addition of process water into thedecanter, the amount of vegetation water generation isvery high. For instance, from 1 t of olives, 1.21.6 t ofvegetation water and also 0.5 t of pomace are generated.The pomace generated has approximately 46.5% drymatter and is very valuable from the point of energycontent, with a calorific value of between 38004500kcal/kg. In the two-phase continuous system, only theoil and pomace containing vegetation water are the out-puts of the process. Here, the vegetation water isaccumulated in pomace, it is not generated separately.Moreover, as there is no water addition in the process,the amount of vegetation water existing in the pomaceis quite low. From 1 t of olives, only 0.0500.060 t ofvegetation water is determined in the pomace which isaround 0.8 t.
The moisture content of pomace generated throughtwo-phase continuous system is about 6065% [6,7,8].In Spain, the leading country in olive oil production,approximately 90% of the oil mills use the two-phasecontinuous system whereas in Italy (the second olive oilproducer of the world) half of the production is stillobtained by the traditional pressing method [6,9].
In Turkey, extraction of the olives, refining and fil-tration of the olive oil and processing of its solid by-products (pomace) are utilized by different enterprisesseparately from each other. Amongst the seventeenindustries selected for the study, fifteen of them wereolive oil extraction SMEs in which the extraction ofolives were obtained by three-phase continuous system.There also existed a refining plant and also there was apomace oil extraction plant in which the residual oil leftin the pomace coming from the first fifteen SMEs wasextracted. These enterprises are related to each other inthe overall production chain. The product of one is rawmaterial of the other. Within this frame, pollution pre-vention in the processes and recovery options for by-products were evaluated. The selected industries are asfollows:
The first fifteen industries that can be defined as(SMEs) are established for the olive fruit extraction toproduce crude olive oil in Edremit. These fifteen SMEsare selling crude olive oil to the refining plant; Unikomin Ayvalk. Finally another SME Yeni Kurtulus locatedin Edremit is responsible for pomace oil extraction.
During the planning and organization phase of CPmethodology, it was noticed that, since the plants arelocated away from each other, a lack of cooperation and
coordination existed, resulting in difficulties for reliabledata collection. Regular meetings among organizationsand information dissemination was not possible. As aresult, very few reliable data were collected. On the con-trary, data evaluation is very important since the appli-cation of CP methodology starts from collecting thebaseline data in order to identify the current status andsources and causes of the sectorial problems.
Also as a systematic barrier, it was concluded thattraining the employees to upgrade their job skills wasnot realized. From the point of governmental barriers,although the exhausted olive pomace is appropriate tobe used as a fuel with its high calorific value, there areno related regulations for its utilization.
During the pre-assessment phase of the study, briefinformation on olive oil production was provided. Inputsand outputs and their cost on the basis of whole oliveoil production are illustrated in Table 1.
The 15 SMEs are the first step of crude olive oil pro-duction where the olives collected in sacks were receivedand processed to produce crude olive oil. The existingextraction system is the three-phase continuous system.Plants operate 90 days a year in on years and 30 daysa year in off years with an operating capacity of 24 hper day. As the year 20002001 was an on year forolive harvesting, all the calculations/assumptions in thisstudy were made according to the production period of2000/2001.
On the other hand, Unikom is the plant where lowquality olive oil is refined, filtered, bottled and sent tomarket. Unikom provides crude olive oil from the SMEsmentioned above. Being in an on year or an off yearperiod for olive oil production does not affect the annualproduction of Unikom.
The pomace, as a by-product generated in the selected15 olive oil extraction SMEs, is processed through pom-ace oil extraction process by means of the solvent calledhexane in the Yeni Kurtulus plant in Edremit. The outputof the process are exhausted olive pomace and olivepomace oil, which have economic value.
3. Assessment phase and evaluation of CP options
According to the results of the pre-assessment phase,the audit focus points from the point of material andenergy balances were determined and derived during theassessment phase. Hence CP options were generated andlisted in order of priority. Within this frame, the crudeolive oil production processes which were carried out in15 SMEs and the processes applied to extract pomaceoil and exhausted pomace in Yeni Kurtulus plant wereselected for the CP implementation. In these plants, adetailed understanding of the sources and causes ofwaste and emission generation was obtained (Figs. 2and 3).
616 S. Gurbuz et al. / Journal of Cleaner Production 12 (2004) 613621
Table 1Inputs and outputs including their costs for olive oil production chain for production period of 2000/2001
Product-by-product 15 Olive oil extraction SMEs Unikom (olive oil refining enterprise) Yeni Kurtulus pomace oil extractionconsumption plant
Raw material Collected olives: 45,000 t/year Crude olive oil: 8930 t/year Pomace: 22,500 t/yearaProduct Crude olive oil: 9000 t/year Total oil production: 80,782 t/yearb Pomace oil: 560 t/yearBy-product and Leaves: 900 t/year Soapstock: 11,715 t/year Exhausted olive pomace: 14,065 t/yearwastes
Clay and stones: 450 t/year Fatty acids: 2028 t/yearVegetation water: 45,00054,000 t/year Sludge: 103 t/year
Wastewater: 50,697 t/yearcPomace: 22,500 t/year
Water consumption Total consumption: 49,50059,400 Total consumption: 115,532 t/year Total consumption: 26,100 t/yeart/year (heating, cooling)
Cost: 125,584/yearCost: noned Water consumption during olive oil Cost: noned
refining: 4500 t/yearCost: 6996/year
Energy consumption Pomace energy: 95,625 104 to 1125 Total electric energy consumption: Pomace energy: 1125 1010 kcal /yeare 106 kcal /year 6,247,702 kW h/yearTotal exhausted pomace consumption: Cost: 543,550/year Electric energy consumption: 385,112255300 t/year kW h/year
Electric energy consumption duringolive oil refining: 150,000 kW h/year
Cost: 51006000/year Cost: 33,505/yearTotal electric consumption: 1,987,185 Cost: 13,050/yearkW h/yearCost: 196,725/year
Chemical No chemical is used Phosphoric acid: 22,500 kg/year Hexane: 22.5 t/yearconsumption
Caustic: 86,250 kg/year Hexane: 45 kg/year (lost duringdistillation)
Citric acid: 6000 kg/yearBleaching earth: 15,000 kg/year Cost of lost hexane: 25.2/year
Note: The chemical consumption quantities given in table for Unikom were calculated according to olive oil production.a Total pomace coming from the 15 olive oil extraction SMEs: 22,...