Revalorization of Posidonia oceanica Waste for the Thermochemical Production of Biochar

Abstract

Every year, many tonnes of Posidonia oceanica are removed from Mediterranean beaches to maintain the quality and pleasure of use of the beaches. Most of this waste ends up in landfills, entailing removal costs. In this work, the Posidonia oceanica material was characterised, and a washing system was developed to obtain biochar. An adequate washing of the starting biomass was shown to play a key role as it led to an over 90% salt content reduction and, therefore, a decrease in conductivity values. The use of biochar as a soil remediator improves soil properties, carbon sequestration, and plant growth. However, not all types of biochars are suitable for this type of application. Therefore, the properties of biochar made from Posidonia oceanica at different temperatures (300, 400, and 500 °C) were studied. All the biochars obtained showed to exceed 10% organic carbon, which is the lower limit to be applied to soils, the maximum percentage having been obtained at 300 °C. In addition, all presented pH values (8.02, 10.32, and 10.38 for the temperatures of 300, 400, and 500 °C, respectively) that were similar to those of other effective biochars for the remediation of acid soils.

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“…The production of biochar from POW by thermochemical processes has been recently studied and evaluated by many researchers. [50][51][52][53] As reported by Molto et al, 53 the application of biochar derived from POW biomass as a soil remediator engenders improved soil properties, carbon sequestration, and plant growth. In addition, thermally treated POW has been proven effective as an adsorbent material for toxic metal ions or as a lowcost adsorbent material for phosphate removal from synthetic and real wastewater (Table 1).…”

The Decomposition Dynamics and Substrate Component Potential of Biomass from the Seagrass Posidonia oceanica (L.) Delile

“…From an ecological standpoint, P. oceanica meadows play a fundamental role in Mediterranean marine ecosystems, significantly contributing to the health and sustainability of coastal ecotone ecosystems [8]. These seagrass meadows support diverse communities, including epiphytic organisms, serving as nurseries and providing food for invertebrates, vertebrates, and juvenile fish [9,10]. Furthermore, P. oceanica roots stabilize the seabed, preventing coastline erosion from wave forces [11].…”