Sulphur fate and anaerobic biodegradation potential during co-digestion of seaweed biomass (Ulva sp.) with pig slurry

► Green seaweed stranded on beaches as agricultural anaerobic digestion co-substrate. ► Methanogenic potential of green seaweed is low. ► Biogas produced by co-digestion with animal slurry contained high level of H2S. ► Further control of H2S production by selective biomass inhibitor is not efficient enough.