초록
Ascophyllum nodosum, an abundant Irish brown seaweed, shows significant seasonal variation in chemical composition and biogas production. The polyphenol content is shown to be a more important factor in biogas production than ash content. High polyphenol content in summer months adversely affected biogas production; suggesting two potential harvest dates, March and October. A. nodosum harvested in October showed a relatively low level of polyphenols (2% of TS) and ash (23% of volatile solids), and exhibited a specific methane yield of 215LCH<SUB>4</SUB>kgVS<SUP>-1</SUP>, which was 44% of theoretical yield. The highest yield per wet weight of 47m<SUP>3</SUP>CH<SUB>4</SUB>t<SUP>-1</SUP> was achieved in October, which is 2.9 times higher than the lowest value (16m<SUP>3</SUP>CH<SUB>4</SUB>t<SUP>-1</SUP>), obtained in December. The gross energy yield of A. nodosum based on the optimal biogas production can achieve 116GJha<SUP>-1</SUP>yr<SUP>-1</SUP> in October.