Simulation-based assessment of anaerobic digestion scenarios for sustainable valorization of Sargassum spp. biomass

Abstract

The massive influx of Sargassum spp. along Caribbean coastlines has emerged as a critical environmental, socioeconomic, and public health issue, prompting the need for sustainable biomass valorization strategies. Although abundant, Sargassum remains underutilized in anaerobic digestion (AD) due to its compositional variability and the presence of inhibitory or recalcitrant compounds, which hinder biodegradability compared to conventional substrates such as manure or food waste. This study evaluated the technical feasibility of using Sargassum spp. as a feedstock in AD systems by simulating both mono-digestion and co-digestion scenarios. Four configurations were modeled under mesophilic conditions using Biodigestor-Pro v3.5, assuming a constant daily feed rate of 1 ton and incorporating operational parameters derived from the literature. The model estimated biogas yields, digestate mass flows, energy generation, and preliminary full-scale plant sizing, including feeding, digestion, gas handling, purification, and power extraction units. Results indicated that the highest outputs of biogas (27,528 m ³ /year), biofertilizer (730 ton/year) and energy (electricity: 53,290 kWh/year; heat: 99,280 kWh/year) were achieved under the co-digestion scenario of Sargassum and pig manure at a 50:50 ratio. Process efficiency could be enhanced through biomass pretreatment, inoculum selection, or performance optimization, which may also enable the recovery of additional high-value products beyond methane and fertilizer within an integrated processing chain. Taken together, these findings offer practical insights for the conceptual design of AD facilities in coastal regions and provide a basis for future, more comprehensive waste-to-energy assessments that integrate techno-economic and life-cycle perspectives.