Abstract
Steam-explosion is a promising technology for recovering phenolic compounds from olive mill solid waste (OMSW) due to its high impact on the structure of the fibre. Moreover, the recovery of the phenols, which are well-known microbial inhibitors, could improve the subsequent biomethanization of the dephenolized OMSW to produce energy. However, there is a considerable lack of knowledge about how the remaining phenolic compounds could affect a long-term biomethanization process of steam-exploded OMSW. This work evaluated a semi-continuous mesophilic anaerobic digestion of dephenolized steam-exploited OMSW during a long operational period (275 days), assessing different organic loading rates (OLRs). The process was stable at an OLR of 1 gVS/(L·d), with a specific production rate of 163 ± 28 mL CH4/(gVS·d). However, the increment of the OLR up to 2 gVS/(L·d) resulted in total exhaust of the methane production. The increment in the propionic acid concentration up to 1486 mg/L could be the main responsible factor for the inhibition. Regardless of the OLR, the concentration of phenolic compounds was always lower than the inhibition limits. Therefore, steam-exploited OMSW could be a suitable substrate for anaerobic digestion at a suitable OLR.
Highlights
The olive oil sector stands as an important economic sector for many countries; some current challenges could risk its economical sustainability
I.e., 0–75 days and organic loading rates (OLRs) = 2 gVS/(L·d), the methane production rate presented a mean value of around 0.369 ± 0.049 gCODCH4 /(gCOD·d), i.e., 152 ± 21 mL CH4 /(gVS·d) (Table 3)
The anaerobic digestion process was stable at an OLR of 1 gVS/(L·d), with a specific production rate of 163 ± 28 mL CH4 /(gVS·d)
Summary
The olive oil sector stands as an important economic sector for many countries; some current challenges could risk its economical sustainability. It is required to develop sustainable and environmentally friendly management for the olive mill solid waste (OMSW) generated during extraction [1]. The OMSW results from the two-phase olive oil manufacturing process, being a high-humidity and polluting waste, where the remains of olive fruit are retained. Each ton of olive oil generates around 4 tons of OMSW each year, and due its high potential impact on the environment [2,3], it is necessary to develop an adequate OMSW management strategy to ensure environmental protection, and economic sustainability of the olive oil sector.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
