Paper Title
Utilization of Lipidic-Waste as Co-Substrate For Enhanced Biomethane Production in Anaerobic Digestion

Abstract
Anaerobic digestion (AD) is a sustainable approach, to recover energy (biomethane), for wastewater sludge and also to reduce the load on landfill by lowering the amount of sludge disposal generated from wastewater treatment plants (WWTPs). However, 50-60% of the organic portion is lost in the effluent sludge from AD, resulting in low biomethane yield. Utilization of various organic wastes in co-digestion with sludge was shown to be beneficial in biomethanation. Recently, anaerobic co-digestion of lipidic-waste such as fat, oil, and grease (FOG) has received much attention for the enhancement of biomethanation in WWTPs. FOG supplementation has been demonstrated in laboratory, pilot, and full-scale operations to have significant impact on biomethane yield. Still there are some major limitations with anaerobic co-digestion (ACD) of FOG which includes inhibition by LCFAs, sludge floatation and washout, and scum formation. Various pretreatment technologies including mechanical, thermos-chemical and biological have been applied to overcome these challenges. Biological treatment is more suitable option as it efficiently degrades saturated fatty acids (SFAs) and unsaturated fatty acids (USFAs) in FOG, and reduces the detrimental effects of FOG in ACD. Metagenomic analysis elucidates the microbial community and the interspecies interactions which are responsible for the degradation of FOG and its biomethanation during ACD.