Influence of n-Hexadecane and Naphthalene on Anaerobic Digestion: Kinetic Simulation, DOM Variation and Microbial Community Assessment

Abstract

Abstract The influences of n-Hexadecane and naphthalene on anaerobic digestion in batch tests were investigated. The batch kinetic analysis showed that the maximum methane accumulations (141.18 mL of n-Hexadecane and 146.76 mL of naphthalene) and production rates (20.48 mL/h of n-Hexadecane and 20.88 mL/h of naphthalene) were obtained while adding with 30 mg/L n-Hexadecane and 2 mg/L naphthalene, respectively. However, a significant inhibition ratio of 10% was observed at 100 mg/L of n-Hexadecane and 20 mg/L of naphthalene, respectively. The 3D-EEM results showed that the naphthalene was degraded by related microorganism as potential carbon source with concentration lower than 10 mg/L. In addition, the microbial community analysis indicated that the abundance of hydrotrophic Methanolinea and Methanobacterium increased from 7.92% to 12.76% as the increase n-Hexadecane, while decreased from 13.01% to 9.07% with increase of naphthalene. Contrastly, the acetoclasstic methanogens were increased due to the well synthetic action with syntrophic VFA-oxidizing bacteria.