Validation of Two Theoretically Derived Equations for Predicting pH in CO2 Biomethanisation

CO2 biomethanisation is a rapidly emerging technology which can contribute to reducing greenhouse gas emissions through the more sustainable use of organic feedstocks. The major technical limitation for in situ systems that reaction causes depletion drives up pH, potentially leading instability and even digestion failure. study aimed test fundamentally derived predictive equations as tools manage H2 addition anaerobic digesters. methodology used data from literature experimental digesters operated with excess point failure subsequent recovery. Two were tested: first relating pH partial pressure (pCO2), second extending this include influence volatile fatty acids ammonia. equation gave good agreement studies covering wide range operating conditions digester types. Where was not good, could usually be explained, some cases improved, using equation, also showed excellent performance study. results validated identified typical coefficient values Both provide basis process control routine monitoring or pCO2 additional analysis total ammonia nitrogen when required.