Energy Recovery from Corn Straw via Batch Anaerobic Digestion: Experimental and Simulation Study Using Rumen Inoculum

Abstract

This study examines the experimental and simulation-based performance of batch anaerobic bioreactors used for the biomethanization of corn straw inoculated with rumen juice from the Masina slaughterhouse. The objective was to evaluate the substrate inoculum interaction under discontinuous operating conditions. Volumetric, gravimetric, and electrometric methods, along with the principle of communicating vessels, were used to monitor the bioconversion process. A two-phase anaerobic digestion model was developed to simulate the evolution of key parameters such as substrate concentration, microbial activity, and methane production over time. Model outputs were compared with experimental results to validate its accuracy and gain insight into degradation dynamics. Two inoculum conditioning strategies were tested to assess their effect on enzymatic activity and methane yield. Preconditioned (non-fresh) rumen juice, combined with a high organic loading rate, significantly improved the hydrolysis of lignocellulosic biomass, leading to faster degradation and enhanced methane productivity. The approach relied on simple, low-cost techniques and delivered promising results. A significant volume of methane was generated after 28 days of digestion, confirming the efficiency of the selected process conditions. These findings highlight the potential of anaerobic digestion for valorizing agricultural waste into bioenergy, particularly in decentralized, resource constrained contexts.The cumulative methane productions for the experimental digesters I, II, III, and IV were 330 mL, 412 mL, 153 mL, and 197 mL respectively, while the simulation predicted a maximum methane production rate of 0.375 L/day at an initial dissolved glucose concentration of 5 g•L-1. These results emphasize the importance of developing local and sustainable biogas production processes from organic waste, thereby contributing to energy transition, greenhouse gas reduction, and the promotion of a circular economy within the renewable energy sector.