It Works! Organic-Waste-Assisted Trichoderma spp. Solid-State Fermentation on Agricultural Digestate

This study aimed at valorizing digestate through Trichoderma spp. solid-state fermentation (SSF) to produce a potentially ameliorated fertilizer combined with fungal biomass as a value-added bioproduct. Plant-growth-promoting Trichoderma atroviride Ta13, T. reesei RUT-C30, T. asperellum R, and T. harzianum T-22 were tested on different SSF substrates: whole digestate (WD), digestate dried up with wood sawdust (SSF1), and digestate enriched with food waste and dried up with wood sawdust (SSF2). The fungal biomass was quantified by using a qPCR assay. The growth of the four Trichoderma spp. was only observed on the SSF2 substrate. The highest quantity of mycelium was produced by T. reesei RUT-30 (689.80 ± 80.53 mg/g substrate), followed by T. atroviride Ta13, and T. asperellum R (584.24 ± 13.36 and 444.79 ± 91.02 mg/g substrate). The germination of Lepidium sativum seeds was evaluated in order to assess the phytoxicity of the Trichoderma-enriched substrate. The treatments with 7.5% SSF2-R, 3.75% SSF2-T-22, and 1.8% SSF2-Ta13 equally enhanced the root elongation in comparison to the non-fermented SSF-2. This study demonstrated that digestate, mixed with agro-food waste, was able to support the cultivation of Trichoderma spp., paving the way to the valorization of fermented digestate as a proper biofertilizer.

Thermal, Mechanical, Morphological and Aesthetical Properties of Rotational Molding PE/Pine Wood Sawdust Composites

This research addresses the importance of pine wood sawdust granulometry on the processing of medium-density polyethylene (MDPE)/wood composites by rotational molding and its effects on the morphological, mechanical and aesthetical properties of parts, aiming to contribute for the development of sustainable wood polymer composites (WPC) for rotational molding applications. Pine wood sawdust was sieved (<150, 150, 300, 500, 710, >1000 µm) and analyzed for its physical, morphological and thermal characteristics. Rotational molded parts were produced with matrix/wood ratios from 90/10 to 70/30 wt% considering different wood granulometries. As a natural material, wood changed its color during processing. Granulometries below 500 µm presented better sintering, homogeneity and less part defects. Furthermore, 300–500 µm favored the impact resistance (1316 N), as irregular brick-shaped wood was able to anchor to PE despite the weak interfacial adhesion observed. The increase of wood content from 10 to 30% reduced the impact properties by 40%, as a result of a highly porous structure formed, revealing sintering difficulties during processing. WPC parts of differentiated aesthetics and functionalities were achieved by rotational molding. A clear relationship between wood granulometry and WPC processing, structure and properties was identified.

Mortar Based on Dune Sand and Substitute Wood Sawdust: Physico-Mechanical Characterization and Relationship Between Properties in Young Age

The South of Algeria is known for these immense sand dunes, which cover part of its territory (Sahara). The main objective of this study is the recovery of sands dune and wood waste (sawdust). The latter, which constitutes a potential source of several environmental and economic problems. The objective of this present work is to characterize the physico-mechanical properties at a young age of a dune sand-based mortar lightened by wood waste and to examine the suitability of using it for various applications in the construction of buildings. The improvement of the characteristics of these sands, which essentially formed of sand untapped to date and with the sole aim of enhancing this national sand wealth. The formulation of the mixtures is based on the substitution of dune sand by sawdust, at different weight contents 0, 10, 20 and 30%. The quantity of cement is fixed at 450 g. The results obtained show firstly that the introduction of sawdust improves the characteristics of the mixture (grain size tends to be spread out, reduction in densities), and secondly the physico-mechanical characteristics, especially at 30% substitution (reduction absorption by total immersion of 20.50%, porosity of 28.32%, wet density of 1.73% and dry density of 14.94% and increase in tensile strength of 61.43% and in compression of 63.87%). The effect of sawdust on the relationships between the properties of mortars was clearly noted either for the relationships between early strengths or between compressive and tensile strengths.

Pemanfaatan Limbah Plastik Dan Serbuk Gergaji Kayu Sebagai Bahan Pengisi Bambu Komposit Setempat

This study aims to determine the mechanical properties (compressive strength and shear strength) of bamboo filled with PET plastic and wood sawdust. Five variations of test objects were made, namely BK-0 (bamboo without filler as a control), BK-1 (bamboo filled with PET plastic), BK-2 (bamboo filled with PET plastic + adhesive coated), BK-3 (bamboo filled with PET plastic + powder wood saw), BK-4 (bamboo filled with PET plastic + wood sawdust and coated with adhesive). The test results give the value of the compressive strength of bamboo from BK-0 to BK-4 in a row of 22.7 MPa, 29.4 MPa, 32.7 MPa, 33.2 MPa, 35.7 MPa or an increase in the compressive strength of BK-0 in a row by 30%, 44%, 46%, and 57%. Meanwhile, the shear strength of bamboo from BK-0 to BK-4 is 4.55 MPa, 5.00 MPa, 5.05 MPa, 5.40 MPa, 5.50 MPa or an increase in shear strength to BK-0 is 10%, 11%, respectively. , 19%, and 21%.