Experimental study on phase separation of two-phase anaerobic reactor

Key words: 
• two-phase anaerobic digestion /
• phase separation /
• molybdate /
• acidification rate

Abstract: Under the conditions of the two-phase up-flow anaerobic sludge bed（UASB）reactor’s successfully dynamic start-up, molybdate was taken as methanogens inhibitor to carry out the further-phase-separation experiment. Sodium molybdate solution was added to the influent of acidogenic reactor at the first three days of the experiment, which concentration was 2.0 mmol/L. Effluent of acidogenic reactor did not flow into methanogenic reactor.Then the acidogenic reactor ran another three days without adding sodium molybdate solution ,while the effluent still did not flow into methanogenic reactor. After six days, effluent of acidogenic reactor started to flow into methanogenic reactor. The final experimental results show that the acid-producing bacteria would quickly recover on the conditions of stopping dosing molybdate (MoO2-4) and the methanogens is killed by MoO2-4.COD removal efficiency in effluent of the acidogenic reactor decreases， but its acidification rate increases by about 50% and eventually stabilizes at about 60%.In addition, the total COD removal efficiency raises.