Residual Forest Biomass in Pinus Stands: Accumulation and Biogas Production Potential

Abstract

Lignocellulosic biomass is an abundant resource that can be valorized for the production of bioenergy. However, studies aiming to quantify the amount of biogas production potential per km forest road are scarce in the literature. In this study, fresh pine needles, pine needle litter, pine branches, and pine bark were digested in batch reactors under mesophilic conditions after a grinding/milling pre-treatment. All samples were collected from a low-altitude Mediterranean Pinus forest (North Greece) adjacent to a category G forest road with a gentle slope. The methane yield of fresh pine needles was between 115 and 164 NmL g−1 volatile solids (VS), depending on the Pinus tree size. Pine needle litter produced a significantly lower methane yield (between 58 and 77 NmL g−1 VS), followed by pine bark (85 NmL g−1 VS) and pine branches (138 NmL g−1 VS). Considering the quantity of pine needle litter accumulated on adjacent forest roads (600 ± 200 g m−2), it was possible to calculate the biomethane production potential per km of forest road (up to 500 Nm3 km−1) if the biomass collected was disposed of at an anaerobic digestion facility. The results of the study demonstrate that residual forest biomass represents an additional resource for bioenergy production. Moreover, harvesting residual forest biomass can decrease the incidence of devastating summer forest fires and their disastrous consequences for the environment, the economy, and the local populations.

Multi-Parametric Analysis Based on Physico-Chemical Characterization and Biochemical Methane Potential Estimation for the Selection of Industrial Wastes as Co-Substrates in Anaerobic Digestion

“…Wastes from agri-food industries are able to improve the nutrient balance, increase the C/N ratio, and optimize biogas production as they are usually easily biodegradable compounds with high carbon contents [7,8]. The same applies for other organic wastes such as herbaceous crops and pruning residues, which have a C/N ratio above the optimum range for anaerobic digestion and low quantities of nutrients [14,16]. The main drawback of these organic wastes is that they need high energy-demand pre-treatments to be used as co-substrates, which makes the valorization process more expensive.…”

“…[8,11]. Other organic wastes with a high heating value (HHV) such as those obtained from the olive oil industry [12], fruits and vegetables produced in markets and stores [13], or even forest and pruning residues [14] have also been investigated for this purpose. However, the mono-digestion of a single substrate usually has some important drawbacks, since the substrate may not have the appropriate physico-chemical characteristics for reaching high efficiencies in CH 4 production.…”

Urban waste upcycling to a recyclable solid acid catalyst for converting levulinic acid platform molecules into high-value products

“…Researchers have explored diverse options for utilizing pine needles, including producing bio-composites (Gairola et al, 2017), briquettes (Mandal et al, 2018;Nurek et al, 2019), biogas (Singh and Sharma, 2021;Eftaxias et al, 2022), bioethanol (Slathia et al, 2020), and carbonaceous materials through thermochemical processes. These carbonaceous materials, known as biochars, can be further functionalized and find application in soil amendments (Nascimento et al, 2023), as adsorbents (Mishra and Mohanty, 2022;Pandey et al, 2022), for enzyme immobilization and photocatalysis (Liu et al, 2015).…”

Biogas Production from Arthrospira platensis Biomass

“…Biogas is produced during the anaerobic digestion (AD) of different types of biomass and waste. Agricultural residues [6,7], food processing waste [8,9], forest residues [10], and municipal solid waste [11] are used as biogas feedstocks. There are some less conventional substrates, such as microalgae [12][13][14][15].…”