Enhancing Bioenergy Recovery from Agro-food Biowastes as a Strategy to Promote Circular Bioeconomy

Abstract

Agro-food industries produce large amounts of wastes challenging innovative and efficient valorisation strategies promoting the circular bioeconomy concept. Anaerobic digestion technology is an interesting route for bioenergy recovery in the agro-food chain sector. In this work, a simple approach is proposed for assessing energy performance of livestock manure and mixed sewage sludge, as substrate by coupling the potential addition of several agro-food biowastes (co-substrate: fruit and vegetable biowastes, fish canning industry, other manures, coffee wastes, and non-edible crops). The results obtained showed an increase of energy performance indicator ranging from 30 to 250% and 62 to 539%, for livestock manure and mixed sewage sludge, respectively. This conceptual approach for feedstocks promotes the circular bioeconomy as it encourages the stakeholders to a smart use of anaerobic biotechnology at rural-level or urban-level.

A pig slurry feast/famine feeding regime strategy to improve mesophilic anaerobic digestion efficiency and digestate hygienisation

“…In this work, a new strategy for livestock effluent management is proposed -namely, the use of pig manure -specifically, from the fattening/finishing phase (FFM) of a closed pig cycle. Manure collection was carried out in this dedicated pig life stage, since it has a higher organic content, which it is expected to optimise the potential of biogas production, as stated by Duarte et al (2020). The main objective of this study was to investigate the reactor feeding frequency with this type of slurry and, consequently, the effect of feast/famine on AD efficiency correlated with the digestate hygienisation degree.…”

Energetic Valorization of Cereal and Exhausted Coffee Wastes Through Anaerobic Co-digestion With Pig Slurry

“…Although the HRT is too short for PS, in the case of the study presented fits well attending to the physico-chemical composition of the pig manure generated in the farm unit, which presents a very low ST and SV concentration and, consequently a very low OLR. Previous studies published by the authors Duarte et al (2021) support this choice. During all the cycles, the process was controlled to maintain appropriate mesophilic conditions (36.9 ± 0.3 • C).…”

“…AD technology is considered as one of the most conventional processes in livestock waste management due to the process simplicity and feedstock flexibility. However, using animal manure as a sole feedstock, particularly swine manure, may not be the most efficient way to produce methane-rich biogas because of its inherent low carbon/nitrogen ratio and because it carries certain constrains, as complex materials require longer retention times and larger digestion volumes (Ros et al, 2017;Lopes et al, 2019;Duarte et al, 2021).…”

Circular Bio-economy—Paradigm for the Future: Systematic Review of Scientific Journal Publications from 2015 to 2021

“…Replacing traditional anaerobic digestion feedstocks with food wastes has significant environmental benefits, not just with regard to reduction in GHGs, but also with regard to avoiding nutrient leakage to the hydrosphere, which would have occurred if the food wastes had been landfilled instead [128]. Interestingly, co-digesting livestock manure and mixed sewage sludge along with fruit, vegetable, coffee, fish-canning industry and crop wastes has been shown to enhance the biogas recovery substantially [68]. While most publications take food waste for granted and decide to focus on how it can be valorised in a circular bioeconomy [244], Oldfield et al (2016) [10] adopt a different approach in an Irish case study.…”