Environmental impacts relative to soil quality caused from the disposal of olive oil mills wastes. Case study : A municipality in Crete, Greece

Transcription

1 Environmental impacts relative to soil quality caused from the disposal of olive oil mills wastes Case study : A municipality in Crete, Greece M. Doula, V. Kavvadias, S. Theocharopoulos, P. Kouloumbis, NAGREF- Soil Science Institute of Athens D. Ikonomou, D. Arapoglou NAGREF- Institute of Technology of Agricultural Products

2 The olive oil tree is amongst the oldest known cultivated trees in the world while the consumption of olives and olive oil is believed to bring health, however, the side products (wastewaters-oomw and solid wastes-sw) from their production and treatment could impact environment negatively if no precautions are taken. It is estimated that there are 6 million productive olive trees on the planet, occupying a surface area of 7 million ha. The Mediterranean region accounts for not less than 97% of the world production Among European countries, but also worldwide, Spain and Italy are the two leaders in olive oil production, whereas Greece holds the third place. The annual oil mills waste production of Mediterranean olivegrowing countries is estimated to ranging from 7 million to over 3 million m 3, depending on annual olive production. The average total production amounts approximately to 1x1 6-12x1 6 m 3 /year and occurs over a brief period of the year (November- March).

3 Annual olive oil Production in Mediterranean for the main olive oil-productive Countries Country 2 (x1 3 t) 21 (x1 3 t) 22 (x1 3 t) 23 (x1 3 t) 24 (x1 3 t) 25 (x1 3 t) 26 (x1 3 t) 27 (x1 3 t) Spain 962, , , Italy 57,4 573,5 574,9 6,5 794,6 671,3 626,8 59,2 Greece 46,4 32,2 381,6 374,9 321,3 386,4 4,6 394,7 Tunisia 115, 3, 72, 28, 13, 21, 17, 194,9 Portugal 26, 35, 31, 36,5 5,1 31,8 51,8 39,

4

5

6

7 1oo Kg olives 1oo-12 Kg wastewater 1 Kg olive oil 5 Kg wastewater It is estimated that : 58% of mills dispose wastes in streams 11,5% of mills dispose wastes in sea and rivers 19,5% of mills dispose wastes on soil

8 Table 1 : Typical composition of wastewaters Parameter Press 3-phase Total solids, g/l 99,7 63,5 Total Suspended Solids,g/l 4,51 2,8 Total Volatile solids, g/l 87,2 57,4 Ash, g/l 9,69 6,13 Total Organic Carbon, g/l 64,1 39,8 Total Kjeldahl Nitrogen, g/l 1,15,76 Phosphorous (P 2 O 5 ), g/l,87,53 ph 4,5 4,8 BOD 5, mg/l COD, mg/l Specific Weight, g/cm 3 1,5 1,5 Conductivity, mmhos/cm 18, 12, Total Sugars, g/l 25,9 16,1 Fats and Oils, g/l 2,8 1,64 Polyalcohols, g/l 4,75 3,19 Total Phenols, g/l 17,2 1,6 Tannins, g/l 6,74 4,1 Potassium (Κ 2 Ο), g/l 3,77 2,37 Sodium (Na 2 O), mg/l Calcium (CaO), mg/l Fe (FeO), mg/l 48,3 32, Magnesium (MgO), mg/l 74, 5, Silicon (SiO 2 ), mg/l 28,6 18, Total Sulfur, mg/l 11 63, Total Chlorine, mg/l Mn, mg/l 18,2 12, Zn, mg/l 19,7 12, Cu, mg/l 1,5 6, Source : Vlyssides et al., ( ) Table 2 : Characteristics of the olive oil processing solid wastes Parameter (%) Press 3-phase Moisture 27,21 5,23 Fats and Oils 8,72 3,89 Proteins 4,77 3,43 Total Sugars 1,38,99 Cellulose 24,14 17,37 Ash 2,36 1,7 Lignin 14,18 1,21 Kjeldahl Nitrogen,71,51 Phosphorous (P 2 O 5 ),7,5 Total Phenols 1,146,326 Potassium (Κ 2 Ο),54,39 Calcium (CaO),61,44 Total Carbon 42,9 29,3 C/N ratio 6,79 57,17 C/P ratio 588, 552,9 Table 3 : Olive oil and wastes production per 1 kg of olives processed Product Press 3- phase Parameter Public sewer Streams Sea Soil network rivers ph Temperature ( ο C) Dissolved Oxygen(mg/l) BOD 5 (mg/l) COD (mg/l) Suspended Solids (mg/l) Fats and Oils (mg/l) Kjeldahl Nitrogen (mg/l) Nitrates (mg/l) Phosphorous (mg/l) 1,2 2 2 Total dissolved solids (mg/l) phase Olive oil Wastewaters Solid residues Table 4 : National Environmental Quality Standards for wastewater disposal in relation to each receptor apply

9 Co-funded by European Commission within the framework of LIFE+ Program. Total Budget :

10 Beneficiaries NAGREF-Soil Science Institute of Athens Technical University of Crete Institute of Mediterranean Studies CERSAA-Centro Regionale di Sperimentazione e Assistenza Agricola CEBAS- Centro de Edafologia y Biologia Aplicada del Segura

11 Project Objectives PROSODOL Development and dissemination of innovative, environment friendly, low cost technologies for the protection of soil and water pollution from olive oil mills wastes. Establishment of an info-library/knowledge-base system to assess environmental impacts from olive oil mills wastes to Mediterranean region. Facilitate the implementation of Soil Thematic Strategy in areas close to olive oil mills. Design, implementation and support a monitoring system for the assessment of the soil and water quality affected directly or indirectly from oil mills activities in relation to factors pressures and responses. Identification of potential safest uses in the agricultural sector of olive oil mills wastes and its possible contribution to agricultural production.

12 Design, implementation and support a monitoring system for the assessment of the soil and water quality affected directly or indirectly from oil mills activities in relation to factors pressures and responses. SOIL Greek Implementation Area : Crete, Municipality of Nikiforos Fokas Total area of 95m 2, 21 Villages, 66 residents Geological formations are mainly identified as limestones, dolomites and marbles Soils are slightly alkaline to alkaline (ph ), clay or silty clay in texture and very rich in carbonates (5-6% CaCO 3 ) Three active olive oil mills (3-phase system with continuous centrifuge extraction systems) and two inactive for more than 5 years Disposal areas contain ponds which were built by excavating the superfacial material of soil and by heaping excavating materials around the pond to form retaining walls. Protective impermeable membranes or other protective media were not used

13 From the five targeted areas, three will be presented. NF1 : is a common disposal area, located in a field with slope of almost 1%. No surface disposal, the movement of wastes constituents is due to gravity NF4 : is very large field with two ponds, of almost 5% slope. The owner disposes waste on soil through a pipe. NF6 : is inactive for more than five years while it was used as disposal area for more than 2 years

14 SAMPLING Soil sampling took place 1 month after the completion of wastes disposal, between 6 th and 9 th May 29. Samples were collected from different distances from the ponds and depths of -25cm, 25-5cm, 5-75cm, 75-1cm, 1-125cm,125-15cm and cm. Samples were collected from inside the ponds at different depths (m) CHEMICAL ANALYSES The preparation of samples for analysis was performed according to ISO 11464:26 method. Laboratory determinations were performed according to the methods usually used for soil characterization. Particle size distribution, ph, Electrical Conductivity (EC), organic matter (OM), total N, available phosphorous, Cation Exchange Capacity (CEC),exchangeable K, Ca, Na and Mg, water soluble Na, available Mn, Fe, Cu and Zn, Boron, Cl -, SO 4 2-, PO 4 3- ions by water extraction, Total Polyphenols content.

15 3 2,5 Electrical Conductivity, ms/cm Active Disposal Area NF4 Surface Disposal Measured in paste extract -25cm 25-5cm 5-75cm 75-1cm 1-125cm cm cm 2 1,5,9,8 Former Disposal Area NF6 1,5,7,6,5 m 1m 3m 4m 25m 5m 75m 9m 15m Control,4,3,2,1 m 15m

16 Active Disposal Areas NF4 Surface Disposal 8 41, m 1m 2m 4m 25m 5m 75m 9m 15m Control NF1 m 2m 4m 1m 12m Control Organic Matter, % Former Disposal Area, NF6 3,5 3 2,5 2 1,5 1,5 m 15m -25cm Determined by dichromate oxidation 25-5cm 5-75cm 75-1cm 1-125cm cm

17 Active Disposal Area NF4 Total Nitrogen (Kjeldahl), mg/g Surface Disposal >2.5mg/g : very rich -25cm 25-5cm 5-75cm 75-1cm 1-125cm cm cm Former Disposal Area, NF6 m 1m 3m 4m 25m 5m 75m 9m 15m Control 2 1 According to ISO 11261:1995 m 15m

18 Available Phosphorous, mg/kg m Active Disposal Area NF4 Surface Disposal 1m 3m 4m 25m 5m 75m 9m 15m Control Extracted with sodium hydrogen carbonate (ISO 11263: 1994) cm 25-5cm 5-75cm 75-1cm 1-125cm cm cm Former Disposal Area, NF ppm : very much sufficient 4 m 15m

19 Exchangeable Potassium, cmol/kg Active Disposal Area NF4 Surface Disposal Extracted with Barium Chloride (ISO 1126:1994) -25cm 25-5cm 5-75cm 75-1cm 1-125cm cm cm Former Disposal Area, NF6 m 1m 3m 4m 25m 5m 75m cmol/kg : sufficient 9m 15m Control 4 2 m 15m

20 Total Polyphenols, mg/kg Active Disposal Area NF Surface Disposal Extracted with Methonol -25cm 25-5cm 5-75cm 75-1cm 1-125cm cm cm m 1m 3m 4m 25m 5m 75m 9m 15m Control Former Disposal Area NF6 m 15m

21 Available Mn, mg/kg Active Disposal Area NF Surface Disposal 2 15 Extracted with DTPA (ISO 1487:21) Mn(IV) reduced to Mn cm 25-5cm 5-75cm 75-1cm 1-125cm cm cm Former Disposal Area, NF6 m 1m 3m 4m 25m 5m -5 ppm : very low 5-15 ppm : low 15-3 ppm : moderate 3-5ppm large > 5 ppm : very large 75m 9m 15m Control 1 5 m 15m

22 Active Disposal Areas NF4 Surface Disposal Available Fe, mg/kg Extracted with DTPA (ISO 1487:21) Fe(III) is reduced to Fe(II) Fe(II) + quinones Fe 3+ > 5 ppm : very large -25cm 25-5cm 5-75cm 75-1cm 1-125cm cm cm 3 NF1 15 Former Disposal Area NF m 2m 4m 1m 12m Control m 15m

23 Conclusions Disposal of untreated OOMW at evaporation ponds without using protective materials has significant effect on chemical properties of soil close to ponds Soil samples collected one month after the completion of wastes disposal are characterized by : Enhanced Nitrogen content Enhanced Polyphenols content Enhanced Organic Matter content, but for the cases of direct disposal on soil Increased Electrical Conductivity Significantly large Phosphorous amounts Increased of available Fe and Mn contents Significant increase in exchangeable K content Inactive disposal area is characterized by normal Organic Matter and Nitrogen contents while exchangeable K; available Mn and Fe, polyphenols, phosphorous and EC remain high

24