地下水硝酸盐污染的原位修复试验研究

发布时间：2018-05-12 05:19

本文选题：地下水 + 硝酸盐污染　；参考：《河北工程大学》2015年硕士论文

【摘要】：由于人类的无限索取和刻意破坏,使得地下水资源硝酸盐污染的情况日渐严重。地下水硝酸盐的污染成为当今社会上备受关注的环境问题,严重影响到人类的生活。本文详细叙述了地下水硝酸盐污染的来源及危害,将不同处理方法(如物理法、化学法、生物法、渗透性反应墙技术)的优缺点进行了对比,得出渗透性反应墙技术是目前地下水污染原位修复的最佳可行性方法。针对全球范围内地下水中硝酸盐污染的去除问题,首先采取静态试验进行前期反应介质的研究。选择释碳性能良好且释氮量较少的松木锯末及工业用还原性零价铁粉共同作为反应介质。随后考察铁粉预处理、反应介质配比及进水p H等因素对后续反应柱脱氮效果的影响。反应结果表明:松木锯末可以为反硝化细菌提供碳源,当铁粉经酸预处理后,C:Fe=2:3及进水p H=7左右时,装置的脱氮效果最好,脱氮率达到72.11%,由于天然地下水的p H值范围为6-9,此时该p H值正好符合。将锯末及铁粉按照静态实验得出的数据混合填充于自制的PRB反应柱中,通过8组试验分别改变进水流速及进水浓度进行脱氮反应得出如下结论:随着进水流速从1cm/h增加到7cm/h,混合反应柱的延程脱氮效率逐渐减小,但一周内内脱氮率均能达到100%,该装置在设计流速范围内脱氮效果较好,但当流速为1cm/h及3cm/h时,装置脱氮效果无明显差别,因此在后续反应中进水流速定为3cm/h;确定进水流速后,将进水浓度由60mg/L增至120mg/L,最终均能实现完全脱氮且无亚硝酸盐氮的积累,进水浓度的增加导致出水中副产物氨氮的增加。在后续实验中,将进水流速定为3cm/h,进水浓度定为80m/L,对比不同填充方式下反应装置的脱氮效果。实验结果表明:实验稳定后,两种不同的填充方式下,地下水中的硝酸盐污染物均能得到高效去除,并且混合填充下连续出水中NO3--N未检出,脱氮率为100%,分段填充脱氮率为93.84%;分段填充出水中氨氮降低到2.28mg/L左右,占去除NO3--N浓度的7%左右;通过实验发现,分段填充能有效的防止出水中二次污染问题的产生。通过微生物群落分析得到的结果表明锯末上优势群落主要有Pseudomonas、Diaphorobacter、Caulobacter。通过该实验的研究结果可以看出,未来可以利用类似的装置来进行地下水硝酸盐的原位修复,但该技术的成功应用需要有适宜的填料和反应装置,在今后的工程实践中定能发挥重要的作用。
[Abstract]:The nitrate pollution of groundwater resources is becoming more and more serious due to the unlimited demand and deliberate destruction. Nitrate pollution in groundwater has become a serious environmental problem, which has seriously affected human life. In this paper, the sources and hazards of nitrate pollution in groundwater are described in detail. The advantages and disadvantages of different treatment methods (such as physical, chemical, biological and permeable reactive wall techniques) are compared. It is concluded that the permeable reactive wall technique is the best feasible method for in situ remediation of groundwater pollution. Aiming at the removal of nitrate pollution from groundwater worldwide, a static test was first carried out to study the pre-reaction medium. Pine sawdust with good carbon release and low nitrogen release was chosen as the reaction medium, and the reduced zero valent iron powder was used as the reaction medium. Then the effects of iron powder pretreatment, reaction medium ratio and influent pH on the denitrification efficiency of the subsequent reaction column were investigated. The reaction results showed that pine sawdust could provide carbon source for denitrifying bacteria. When iron powder was pretreated with acid, the denitrification efficiency of the plant was the best when the iron powder was pretreated with C _ (10) Fe _ (2): 3 and influent p H _ (7). The denitrification rate is 72.11. Since the pH range of natural groundwater is 6-9, the pH value of natural groundwater coincides with that of natural groundwater. The sawdust and iron powder were mixed and filled in the self-made PRB reaction column according to the data obtained from the static experiment. By changing the influent flow rate and influent concentration, the following conclusions are drawn: with the increase of influent flow rate from 1cm/h to 7 cm / h, the delayed denitrification efficiency of the mixed reaction column decreases gradually. However, the denitrification rate can reach 100% within one week. The denitrification rate of the device is better in the design flow rate range, but when the flow rate is 1cm/h and 3cm/h, the denitrification effect of the device has no obvious difference, so in the subsequent reaction, the influent flow rate is set at 3 cm / h; after determining the influent flow rate, When the influent concentration was increased from 60mg/L to 120mg / L, the total denitrification and the accumulation of nitrite nitrogen could be realized. The increase of influent concentration resulted in the increase of ammonia nitrogen, the by-product of the effluent. In the subsequent experiments, the influent flow rate was set at 3 cm / h and the influent concentration was set at 80 m / L, and the denitrification efficiency of the reactor was compared under different filling conditions. The experimental results show that the nitrate pollutants in groundwater can be removed efficiently under two different filling modes after the experiment is stable, and the NO3--N in the continuous effluent is not detected under mixed filling. The nitrogen removal rate was 100 and the nitrogen removal rate was 93.84. The ammonia nitrogen in the water was reduced to about 7% of the NO3--N removal concentration. The experimental results showed that the subsection filling could effectively prevent the secondary pollution in the effluent. The results of microbial community analysis showed that the dominant community on sawdust was Pseudomonas sinensis Diaphorobacterus Caulobacter. It can be seen from the results of this experiment that similar devices can be used for the in-situ remediation of nitrate in groundwater in the future, but the successful application of this technique requires suitable fillers and reaction devices. It will play an important role in the future engineering practice.
【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X523

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