The impacts of calcium oxide nanoparticles on the anaerobic granule formation: CO₂ sequestration and dosing

Lab experiments were conducted to investigate the effects of calcium oxide nanoparticles (CaO NPs) dosing on granule formation, granule development, and carbon oxide sequestration. The results showed that dosing CaO NPs adversely affected granulation due to the formation of precipitates and hydrolyzates with poor settleability. However, the optimal dosage of CaO NPs 4.5 g/l could benefit granule formation and stability by improving the embedded extracellular polymeric substances (EPS) and physical adhesion aggregation leads for CO₂ sequestration. The network of granules like Methanosarcina and in pore size 0.55 mm obtained in the reactor was 6.25 mm in average diameter, had a wet density 46 cm², sludge volume index 0.935 ml/g, and CO₂ sequestration 96.7% at 4.5 g/l CaO NP. The proposed study can provide a good prediction for the growth of granules stable texture in regular, dense, rigid, upper part smooth with below surface rough and granule yield showed CH₄ production 4.6 m³/d and CO₂ sequestration 4.75 l/gVS granules (w/v) granules. This study is a useful tool for studying the growth of granule growth characteristics and the mechanism of anaerobic granules for CO₂ sequestration from wastewater.