Optimisation of biogas production from the macroalgae Laminaria sp. at different periods of harvesting in Ireland

• Published in: Applied energy Vol. 177; pp. 671 - 682
• Main Authors: Montingelli, Maria E., Benyounis, Khaled Y., Quilty, Brid, Stokes, Joseph, Olabi, Abdul G.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2016
• Subjects: Anaerobic digestion; Biogas; Harvesting; Laminaria; Laminaria sp; Methane; Optimization; Organic substrate concentration; Pretreatment; Response surface methodology; Seasonal variations; Seaweeds; Substrates; ANE, Eire; Laminaria sp; Biogas; Pretreatment; Response surface methodology; Organic substrate concentration; Anaerobic digestion
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2016.05.150

•Autumn was the best harvesting period of Laminaria sp. as feedstock for AD, in Ireland.•During spring, the system was improved by applying the pretreatment and at a VS concentration of 2.5%.•Higher methane yields were observed at short pretreatment times and at VS concentration below 2.5%.•A positive energy balance was estimated in autumn and early spring. Brown seaweeds are a suitable substrate for biogas production through anaerobic digestion (AD). Since the carbohydrates’ content is subjected to a seasonal variation, this research aimed to select the best harvesting period of beach cast brown seaweed Laminaria sp. for methane production, while optimising the use of a beating pretreatment and the organic substrate concentration. Response surface methodology (RSM) was used to estimate the effect of the beating pretreatment in terms of pretreatment time (5–10–15min) and organic matter concentration in terms of volatile solids (VS) (1–2.5–4%) on methane production. The highest methane yield of 342±17mlg−1 VS was observed during November at 1% of VS and after 5min of pretreatment, while the lowest yields were registered in March with an average of 163±28mlg−1 VS. However, an enhancement of 47% with respect to the untreated sample was achieved at 2.5% of VS and after 15min of pretreatment, in March.