Sustainable and effective utilization of olive mill wastes by applying physicochemical

and biological processes

A.G. Vlyssides, professor National Technical University of Athens

Chemical Engineering Department

World wide olive oil production

Europe Africa Asia America

84%

8.5% 5.5%2%

European Olive Oil Production

42%

20% 18% 20%

Greek situation

The olives and olive oil are inextricable part of Greek

culture

In Greece there are 150.000.000 olive trees cultivated

in 765.000 hectare

The yearly production of each tree rises up to 300 kg

of olives

The 1/3 of Greek farmers are working on cultivation

of olives

Olives and olive oil production in Greece rise up

1.750.000 tn and 400.000 tn respectively

Situation in Greece

INSTALLATIONS

2,633 olive oil mills

2,152 centrifugal systems (mostly 3-phases)

481 traditional (pressure squeezing)

20 pomace processing plants

OLIVE MILL-ΙΙΙ phases

10 tn olives0

134.4 tn water

21.4 tn olive oil

49.6 tn pomace

163.4 tn wastewater

Total Solids 63.5 (TS) g/lTotal Suspended Solids (TSS) 2.8 g/lTotal Volatile Solids (TVS) 57.37 g/lAsh g/l6.13 Total Organic Carbon TOC) 39.82 g/l (Total Organic Nitrogen g/l (ΤΚΝ) 0.76 Total Phosphorus P O g/l ( ) 0.53 2 5

pH 4.8BOD 45.5 g/l5

COD 92.5 g/lolive oil 15 g/lConductivity mmhos/cm 12 Total Phenolic Compounds TPCs) 10.65 g/l (Potasium g/l (Κ Ο) 2.37 2

Dry mater (DM) 22.4 tnTotal Organic Carbon (TOC) 9.5 tnkernel oil 1 tn

Proper characteristics for any success treatment method

•To be technical effective

•To be integrated

•To be feasible

•To meet all Environmental limits

Marketable byproducts from OMW

•Waste olive oil

•energy

•antioxidants

•Soil conditioner

DETOXIFICATION USING Fenton REAGENTS BEFOR ANY BIOLOGICAL TREATMENT

Basic Fenton Reaction

Fe 2 + H2O2 → Fe 3 + ΗO + ΗΟ

Laboratory scale apparatus for chemical oxidation

Laboratory scale apparatus for anaerobic digestion activity determination

Optimum results for %TPC reduction

Maximum reduction TPC∞ = 92 %

Conditions:

Initial conc of H2O2 : 3.037 g/l

Initial conc of Fe++ : 0.44 g/l

pH : 0.86

Temperature oC : 21.3 οC

Lab scale UASB type continuous operation anaerobic digester for methane production from oxidized OMWW

Optimum results for Kmax

Maximum kmax= 0.9 m3 of CH4/kg of VSS/d

conditions:

Initial conc of H2O2 : 3.2 g/l

Initial conc of Fe++ : 0.06 g/l

pH : 1.75

Τ : 15.7 οC

BIOREFINARY FOR OLIVE WASTES TOTALLY UTILIZATION

Olive extraction from OMWW

Waste olive oil collection from OMWW

Pilot scale anaerobic digestion of OMWW

Biogas flare

Co-composting of solids with liquid Olive Mill wastes

Characteristics of the soil conditioner

Parameter Value Limitations

Water Holding Capasity 248 g/L >150

Germination Intex 235 % >100

ratio C/N 17.9 >15

Organic mater 85.5% >60

Ash 12.2% <25

Organic Carbon 43.5% >30

Total Nitrogen 2.42% >1

Total phosphorous 1.78 g/kg >0.35

Cationic Echange Capasity (CEC) 62 meq/100g >50

Humic compounds 40.5 % >25

pH 7.8 6.5-8.5

Cultivation of grapes

Grape for wine

making

0% and 10% mixture of with conventional soil

Comparison after two months cultivation

Basic concept of sustainability of olive cultivation

Annual mass balance of proposed integrated method for a normal capacity Greek Olive Oil Mill

Conclusions

•The fenton oxidation is a key for effective detoxification of OMWW

•After detoxification the anaerobic digestion could be used for energy production

•The proper combination of detoxified and anaerobicaly treated OMWW with the solid wastes of Olive Mills in a co-composting process could give an effective, feasible and integrated method for OMWW green management

Thank you for your attention