Volatile Fatty Acids Production through Degradation of Biomass by Anaerobic Digestion (Mesophilic and Thermophilic)

Abstract

Volatile fatty acids (VFAs) are fatty acids with a carbon chain of six carbons or fewer and usually referred to as short-chain fatty acids (SCFA). Degradation of biomass through anaerobic digestion will produce volatile fatty acid (VFAs) through anaerobic digestion process. The volatile fatty acids obtained can be recovered and used to produce methyl or ethyl esters which, could be advantageously used as additive for biodiesel [1]. Anaerobic digestion is a biological process that can degrade waste organic material by concerted action of a wide range of microorganisms in the absence of oxygen. The objective of this study is to degrade the biomass through anaerobic digestion for the production of volatile fatty acids by two different temperatures condition which are mesophilic and thermophilic; 35°C and 55°C respectively. The production of volatile fatty acids was optimized by varying the cycle period of the digestion process with the concentration of Mixed Liquor Suspended Solid (MLSS) maintained at 8000 mg/L for each cycle. The degradation of biomass was carried out using anaerobic sludge digester which 2L of biomass was digested from day 1 until day 24 (cycle period). The tests of MLSS and Mixed Liquor Volatile Suspended Solid (MLVSS) was conducted by Standard Method 2540-D while test for VFAs was conducted through Standard Method 8196. The highest production of volatile fatty acids was obtained in day 5 of cycle period where the concentration is 441 mg/L as acetic acid (HOAC).