Optimization of Biomethane Production in Mono-Cardboard Digestion: Key Parameters Influence, Batch Test Kinetic Evaluation, and DOM Indicators Variation

Abstract

Mono-cardboard waste digestion in batch tests associated with different impact factors was investigated. The maximum methane generation was 394 mL/gVSadd with the best F/M of 0.5 at mesophilic conditions. The highest methane content reached 75% in the dynamic water bath feeding with an average particle size of 1–3 mm. Hydrolysis and methanogenesis were significantly different between static and dynamic states, especially at particle size over 3 mm. The modified Gompertz model (R 2 > 0.98) and the modified Aiba model (R 2 > 0.88) were the most appropriate models for methane generation among the six kinds of models. At different TS, the variation of dissolved organic matters reflects the metabolic rate of the microbial community. The soluble microbial product-like and protein-like components half split by excitation–emission matrix-parallel factors significantly negatively corresponded to biomethane production. Moreover, a rapid loss of methanogenesis was observed with high organics concentration. A strong correlation between the F/M ratio and the CH4 generation ability was observed with an optimized F/M of 0.5. The maximum energy production was also investigated based on the optimized particle size of 2–5 mm and F/M of 0.5, in which long-term stability was maintained.

Process Modeling and Optimization of Anaerobic Co-Digestion of Peanut Hulls and Swine Manure Using Response Surface Methodology

“…Besides, adopting mathematical models to evaluate its efficiency has been grossly under-reported. 15,16 Dahunsi used the artificial neural networks and response surface methodology (RSM) to investigate the co-digestion of Arachis hypogaea hulls and poultry droppings and found that a higher methane content can be obtained at a temperature of 32 °C, pH of 7.62, and retention time of 30 days. 13 They also confirmed that the use of thermoalkaline pretreatments prior to AD can lead to higher biogas production.…”