Assessment of energy efficiency and performance in a two-phase anaerobic process for organic matter removal

摘要

The energy efficiency (EE) depends mainly on the lower heating values (LHVs) of hydrogen and methane selected from the thermodynamics tables at ideal conditions. However, for practical applications, the heating value should be calculated by considering some environmental factors under real conditions. Accordingly, this study compares the EE using the ideal LHV with the EE using the real LHV in a two-phase AD reactor treating synthetic wastewater. Additionally, the process performance and the stability were studied. The results show that the EE value calculated using LHVideal was, on average, 35% higher than that evaluated using LHVreal; these differences are relevant to the estimation of the real energy and also for the practical applications. At the same time, the index buffer IA/PA (intermediate alkalinity/partial alkalinity) showed to be more accurate than the value of the pH to analyze the stability of the process. With regard to COD, the removal efficiency in the methanogenic phase decreases drastically by utilizing 100% of the acidogenic phase. Future considerations in the optimization of each phase are highlighted.