Impact of milling, enzyme addition, and steam explosion on the solid waste biomethanation of an olive oil production plant
- 327 Downloads
Anaerobic digestion is a consolidated bioprocess which can be further enhanced by incorporating an upstream pretreatment unit. The olive oil production produces a large amount of solid waste which needs to be properly managed and disposed. Three different pretreatment techniques were evaluated in regard to their impact on the anaerobic biodegradability: manual milling of olive pomace (OP), enzyme maceration, direct enzyme addition, and thermal hydrolysis of two-phase olive mill waste. The Gompertz equation was used to obtain parameters for comparison purposes. A substrate/inoculum ratio 0.5 was found to be the best to be used in anaerobic batch test with olive pomace as substrate. Mechanical pretreatment of OP by milling increases the methane production rate while keeping the maximum methane yield. The enzymatic pretreatment showed different results depending on the chosen pretreatment strategies. After the enzymatic maceration pretreatment, a methane production of 274 ml CH4 g VS added −1 was achieved, which represents an improvement of 32 and 71 % compared to the blank and control, respectively. The direct enzyme addition pretreatment showed no improvement in both the rate and the maximum methane production. Steam explosion showed no improvement on the anaerobic degradability of two-phase olive mill waste; however, thermal hydrolysis with no rapid depressurization enhanced notoriously both the maximum rate (50 %) and methane yield (70 %).
KeywordsAlpeorujo Anaerobic digestion BMP Enzymatic pretreatment
This study was funded by Fondecyt Initiation Project No. 11130462 and supported by CIRIC-INRIA-Chile (EP BIONATURE) through Innova Chile Project.
- 13.Angelidaki I, Alves M, Bolzonella D, Borzacconi L, Campos JL, Guwy AJ, Kalyuzhnyi S, Jenicek P, van Lier JB (2009) Defining the biomethane potential (BMP) of solid organic wastes and energy crops: a proposed protocol for batch assays. Water Sci Technol 59:927–934. doi: 10.2166/wst.2009.040 CrossRefGoogle Scholar
- 15.Latimer GW (2012) Official methods of analysis of AOAC International, 19th edn. AOAC InternationalGoogle Scholar
- 21.Chudoba P, Capdeville B, Chudoba J (1992) Explanation of biological meaning of the S(o)/X(o) ratio in batch cultivation. Water Sci Technol 26:743–751Google Scholar
- 30.Monlau F, Sambusiti C, Barakat A, Quéméneur M, Trably E, Steyer JP, Carrère H (2014) Do furanic and phenolic compounds of lignocellulosic and algae biomass hydrolyzate inhibit anaerobic mixed cultures? A comprehensive review. Biotechnol Adv 32:934–951. doi: 10.1016/j.biotechadv.2014.04.007 CrossRefGoogle Scholar
- 32.Pontoni L, d’Antonio G, Esposito G, Fabriccino M, Frunzo L, Pirozzi F (2015) Thermal pretreatment of olive mill wastewater for efficient methane production: control of aromatic substances degradation by monitoring cyclohexane carboxylic acid. Environ Technol 13–16:1785–1794. doi: 10.1080/09593330.2015.1012179 CrossRefGoogle Scholar