甲醇为碳源时C/N对反硝化过程中亚硝酸盐积累的影响

如何获得稳定的NO2--N作为厌氧氨氧化细菌的电子受体是城镇污水通过厌氧氨氧化途径脱氮的瓶颈问题。为此考虑利用反硝化途径获取稳定的NO2--N。以甲醇为碳源,采用小试装置的SBR反应器,通过控制进水C/N(COD与NO3--N质量浓度比)的策略,研究了反硝化过程中的NO2--N积累的状况。试验结果表明以甲醇为碳源且投加量不足时(C/N3.2),反硝化过程中和反硝化结束后会产生稳定的NO2--N积累;在C/N不足的前提下,NO2--N积累量随甲醇投加量的增加而增加;进水C/N为2.4～3.2时,可获得约25%的NO2--N积累率;进水C/N为0.8时,NO2--N积累率仅为5.6%;C/N1时,NO2--N与NO3--N的还原速率随着COD浓度的增加而增加;C/N≥1时,COD浓度不再影响NO2--N与NO3--N的还原速率。

Effect of C/N ratio on nitrite accumulation in dentrifying process with methanol as carbon source

How to get stable and sufficient nitrite as an electronic acceptor of anammox bacteria is a bottleneck of nitrogen removal in treatment of municipal wastewater by anaerobic ammonium oxidation reaction processes. Therefore, denitrification processes was considered as an alternative to obtain stable nitrite. The nitrite accumulation during denitrification processes was studied in a bench-scale sequencing batch reactor with methanol as carbon source by controlling initial C/N (COD/NO^-₃-N) ratios in influent. The results showed that, the shortage of methanol feed(C/N ratios<3.2) during denitrification process would lead to stable nitrite accumulation that increases with raising of methanol feed(C/N ratios increasing).Nitrite accumulation rate (accumulated nitrite/initial nitrate×100%) is about 25% at C/N ratios 2.4—3.2, only 5.6% at C/N ratio 0.8. The reduction rate of NO^-₂-N and NO^-₃-N goes up with the concentration of COD when C/N ratios<1, and is not affected by COD concentration when C/N ratios≥1.