Anaerobic digestion of olive production residue and olive oil production residue by process of bioaugmentation

Rezidbeni ostaci nastali održavanjem nasada, kao i komina masline nastala proizvodnjom maslinovog ulja predstavljaju ostatak koji se može koristiti za proizvodnju energije iz obnovljivih izvora. Navedeni ostaci mogu se zbrinuti procesom anaerobne digestije, tijekom koje se proizvodi bioplin, pri čemu se smanjuje količina otpada i utjecaj na okoliš. Cilj ovog rada bio je utvrditi mogućnost anaerobne digestije rezidbenih ostataka te komine maslina bioaugmentacijom reaktora za proizvodnju bioplina. Bioaugmentacija je postupak dodavanja selektiranih mikroorganizama u biotehnološki proces kako bi se ubrzala razgradnja i radi poboljšanja učinkovitost procesa. Analizom komine, utvrđene su prosječne vrijednosti sadržaja vode 4,84 %, pepela 2,24 %, koksa 15,17 %, gornje ogrjevne vrijednosti 19,33 MJ/kg. Postavljena su 4 različita bioaugmentirana reaktora za anaerobnu digestiju koji su kao supstrat imali kominu masline. Najveći prinos bioplina pokazali su bioreaktori s dodatkom suspenzije bakterija (106,65 mL g-1s.tv.) i dodatkom biočestica (99,86 mL g-1s.tv.), u slučaju bioreaktora s dodatkom perlita prinos je bio isti kao u bioreaktoru bez dodatka (74,88 mL g-1s.tv.). Analizama orezane biomase, utvrđene su prosječne vrijednosti sadržaja vode 10,56 %, pepela 2,91 %, koksa 8,85 %, gornje ogrjevnu vrijednost 19,41 MJ/kg. Postavljena su 4 različita bioaugmentirana reaktora za anaerobnu digestiju koji su kao supstrat imali orezanu biomasu masline. Najveći prinos bioplina u reaktorima s orezanom biomasom pokazali su biorektori sa dodatkom suspenzije bakterija (43,88 mL g-1s.tv.) i bioreaktor sa dodatkom biočestica (42,35 mL g-1s.tv.), bioreaktora sa samom orezanom biomasom postigao je malo veće prinose bioplina (33,20 mL g-1s.tv.) u odnosu na onaj s perlitom (27,37 mL g-1s.tv.). Na temelju provedenog istraživanja, može se zaključiti da je proces bioaugmentacije pozitivno utjecao na stabilnost procesa i prinos bioplina iz komine i orezane biomase. Utvrđeno je da proces bioaugmentacije ima pozitivan utjecaj na biodostupnost hranjiva iz lignocelulozne biomase koja koriste anaerobni organizmi za proizvodnju bioplina.Olive tree residues formed by pruning, as well as olive pomace formed during the process of olive oil production represent the biomass that can be used for renewable energy production. By using the residues for production of biogas by process of anerobic digestion biogas is made, production residues are disposed and reduced environmental impact. The aim of this research wat to determine the possibility of influence on anaerobic digestion of olive tree prunings and olive pomace by bioaugmentation of the bioreactors. Bioaugmentation is a process in which by adding additional microorganisms in the biotechnological process to speed up the process and improve efficiency. Olive pomace analysis show medium values for: moisture content 4.84 %, ash 2.24 %, coke 15.17 %, high heat value 19.33 MJ/kg. Four different bioaugmented bioreactors were setup for anaerobic digestion which used olive pomace. Highest biogas yield was present in bioreactor with added bacteria suspension (106.65 mL g-1dm) and with added bioparticles (99.86 mL g-1 dm), in the case of perlit the yield was the same as the bioreactor with no additions (74.88 mL g-1 dm). Olive tree prunings analysis show medium values for: moisture 10.56 %, ash 2.91 %, coke 8.85 %, higher heating value 19.41 MJ/kg. Four different bioaugmented bioreactors were setup for anaerobic digestion which used olive tree prunings. Highest biogas yield was present in bioreactor with added bacteria suspension (44.88 mL g-1 dm) and bioreactor with added bioparticles (42.35 mL g-1dm), bioreactor with no additions had slightly bigger biogas yields (33.20 mL g-1 dm) than the bioreactor with perlit (27.37 mL g-1 dm). The bioaugmentation process had a positive effect on the stability of the process and the yield of biogas from olive pomace and pruned olive biomass. It was concluded that the process of bioaugmentation has a positive effect on bioavailability of nutrients in lignocellulose biomass used by aerobic microorganisms for production of biogas