Anaerobic Digestion of Hemicellulosic Sugars Implemented in ADM1

Abstract

Lignocellulosic biomass is a sustainable and renewable source for both solids like biochar and biomethane by anaerobic digestion (AD). Hot water extraction (HWE) improves the total utilization of the biomass and produces a hydrolysate rich in hemicellulosic sugars with characteristics that needs to be understood. A study of the AD process in batch reactors with synthetic substrates composed of hemicellulosic sugars was performed and modelled using the standard IWA Anaerobic Digestion Model No. 1 (ADM1). Simulations were also performed using three strategies: 1) varying the stoichiometry for monosaccharide degradation, 2) varying the maximum uptake rate of the monosaccharide degrading organisms and 3) including a first order rate limiting step. The ADM1 model is a good tool but gave initially moderate agreement with the experimental results. The first two strategies did not improve the simulations but it improved significantly upon incorporating a rate limiting step, thereby simulating possible effects based on types of microorganisms present and diffusion limitations.