UASB 공정에서 유입수의 C/Nitrate 비가 메탄화 및 탈질화에 미치는 영향

초록

This paper shows the experimental results during seven months operation from an anaerobic system treating swine waste. The system was composed of an upflow anaerobic sludge blanket (UASB) and the equipment for its denitrification of nitrate nitrogen which is injected into UASB. To induce the denitrification reaction in UASB reactor, nitrate stock solution (KNO₃) with the same flowrate as the swine wastes was fed to the separated feed line with the swine wastes. Nitrate was injected ranged from 50 mg/L to 1,000 mg/L. C/Nitrate ratio was operated at a rate from 6.7 to 79. The UASB reactor was operated at an organic volumetric loading rate (VLR) of from 1.12 kg to 2.28 kg TCODCr/m³/day and the removal rate of TCODCr was from 61.6% to 68.8%. As the C/Nitrate ratio decreased, the removal rate of SCODCr gradually increased and was more than 80% at the C/Nitrate ratio was below 12.4. The nitrate removal efficiency was higher than 95% at C/Nitrate ratio above 12.4. It means that short chain fatty acids generated by the acid former and the volatile fatty acids (VFAs) in influent wastewater were easily available for an electron donor in denitrificaiton. Methane production bacteria (MPB) was severe inhibited and methane generation was not happened at C/Nitrate ratio was 6.7. It means that organics removal was possible only by denitrifiers. Consequently, simultaneous denitrification and methanogenesis of the swine wastes containing high concentration of nitrate was performed successfully in UASB reactor.

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