The Use of Solidified Carbon Dioxide in the Aerobic Granular Sludge Pre-Treatment before Thermophilic Anaerobic Digestion

The most common technology for the recovery of energy and valuable materials from sewage sludge is anaerobic digestion (AD). Ensuring thermophilic conditions during AD has been proven to cause process intensification an improvement in its final outcomes. Nonetheless, search underway other methods bolster effectiveness aerobic granular (AGS), which characterized by a compact complex structure. A prospective AGS pre-treatment entails use solidified carbon dioxide (SCO2). present study focused on evaluation with SCO2 technological effects. It evaluated effect method changes concentrations organic biogenic compounds dissolved phase yield kinetics biogas methane production periodical reactors, as well enabled development empirical organizational model production. introduced caused increase content COD, N-NH4+, P-PO43− at SCO2/AGS volumetric ratios ranging 0 0.3. further dose did not any statistically significant differences this respect. highest yields were obtained 0.3 reached 482 ± 21 cm3/gVS 337 14 cm3/gVS, respectively. higher doses used led decrease pH value AGS, which, turn, contributed decreasing CH4 concentration biogas.