竹刨花-铁耦合体系对低碳氮比污水的脱氮性能

针对低碳氮比污水中总氮（TN）去除率低的问题，以纤维状竹刨花为固体碳源，单质铁粉为铁源，利用二者的耦合作用进行脱氮。通过静态反硝化试验考察不同铁碳质量比（Fe/C）对NO₃ ⁻-N去除效果的影响，确定耦合体系适宜的Fe/C；在此基础上，设置单纯竹刨花对照组（1^#试验组）与耦合填料试验组（2^#试验组）动态反硝化试验，研究其脱氮性能。结果表明：静态试验中，加入铁粉的耦合体系NO₃ ⁻-N去除率均高于单纯竹刨花体系，但当Fe/C大于 0.125∶1时，NO₃ ⁻-N去除率提升不显著，综合考虑反硝化效果与成本，确定动态试验耦合填料Fe/C为 0.125∶1。动态试验中，进水总有机碳浓度低于2 mg/L，TN浓度为（40.93±2.04） mg/L，水力停留时间为18 h时，1^#和2^#试验组运行约10 d后脱氮效能趋于稳定。12~81 d，2组出水总有机碳浓度均较低，1^#、2^#试验组TN平均去除率分别为33%和76%，2^#试验组的TN去除率相比1^#试验组提高了129%；两组均有一定的NO₂ ⁻-N积累，但2^#试验组的NO₂ ⁻-N浓度相比1^#试验组低约47%；2^#试验组出水总铁平均浓度低于GB 3838—2002《地表水环境质量标准》限值，未出现铁过量释放与NH₃-N明显积累。总之，竹刨花-铁耦合体系脱氮效能优异，脱氮过程二次影响低。我国竹资源丰富，铁来源广泛，竹刨花-铁耦合体系可用于低碳氮比生活污水中TN的去除。

Denitrification performance of bamboo shavings-iron coupled system for low C/N ration wastewater

To address the problem of insufficient removal of total nitrogen (TN) from low C/N ratio effluent, fibrous bamboo shavings were used as a solid carbon source and elemental iron powder as an iron source, and the coupling of the two materials was used for nitrogen removal. Static denitrification experiments were conducted to investigate the effect of different Fe/C mass ratios on nitrate-nitrogen (NO3 −-N) removal and to determine the appropriate Fe/C ratio for the coupled system. On this basis, the dynamic denitrification test was divided into a control group of simple bamboo shavings (1#) and a test group of coupled fillers (2#) to study their denitrification performance. The results of static tests showed that the NO3 −-N removal rate of the coupled system with the addition of iron powder was higher than that of the simple bamboo shavings system, but when Fe/C was greater than 0.125: 1, the improvement of NO3 −-N removal was not significant. Taking into account the denitrification effect and cost, Fe/C ratio of the coupled fillers in the dynamic test was determined to be 0.125∶1. The dynamic test results showed that, when the influent TOC was <2 mg/L , TN was (40.93±2.04) mg/L, and hydraulic retention time of 18 h, the denitrification efficiency of 1# and 2# stabilized after running about 10 d. 12-81 d, the effluent TOC of both groups were low, and the average TN removal rates of 1# and 2# were 32.99% and 75.58%, respectively, and TN removal rate of 2# increased by 129% higher than that of 1#; both groups had some nitrite nitrogen (NO2 −-N) accumulation, but the NO2 −-N concentration of 2# was about 47% lower than that of 1#; the average concentration of total iron in the effluent of 2# was lower than the limit value of Surface Water Environmental Quality Standard (GB 3838-2002), and there was no excessive iron release and obvious ammonia nitrogen (NH3-N) accumulation. In conclusion, the bamboo shavings-iron coupled system has significant denitrification efficiency and low secondary effects. China is rich in bamboo resources and has a wide source of iron, and the bamboo shavings-iron coupled system can be used for TN removal of low C/N ratio domestic wastewater.