基于玉米芯的固相反硝化柱实验研究

Performance of Corncob-based Solid Phase Denitrification System: A Column Study

选用农业废弃物玉米芯作为固态碳源,采用一维柱实验研究玉米芯在流场环境下的反硝化性能.结果显示固相反硝化过程中,反硝化速率和氮素形态转化受水力停留时间的影响显著,水力停留时间增加可提高反硝化速率,但它在一定范围内可造成亚硝酸盐的生成,水力停留时间太长时可造成氨的累积.水溶性碳氮比也是影响固相反硝化的重要因素,适宜的碳氮比可提高硝酸盐去除速率且抑制亚硝酸盐和铵盐的产生.实验结果表明,玉米芯固相反硝化系统的最佳水力停留时间为16 h,最适宜的硝氮进水浓度为50 mg·L^-1.玉米芯能够向水相稳定释放TOC为反硝化提供电子供体,SEM结果显示其表面结构也有利于微生物附着生长,因此作为原位可渗透反应墙的填充介质具有很好的应用潜力.微生物鉴定结果表明Pseudomonas sp在玉米芯介质固相反硝化的过程中为主要作用菌属.

Corncob,a typical agricultural waste,is studied as the carbon source for solid phase denitrification under dynamic flow conditions by using 1-D column experiment.The results show that the hydraulic retention time has significant effect on the denitrification rate and transformation between the nitrogen species.The increase of hydraulic retention time can improve the denitrification rate,however,it can cause the accumulation of nitrite when it is in a proper range or ammonium if it is too large.C/N ratio is also an important factor affecting the solid phase denitrification.Appropriate C/N ratio can improve the nitrate removal rate and inhibit the production of nitrite and ammonium.The results show that the optimal hydraulic retention time of the system is 16 h,and the proper nitrate concentration for the system to treat is 50 mg·L^-1.Corncob has good application potential as the packing material of permeable reactive barrier for solid phase denitrification,as it can steadily release the water-soluble TOC to provide electron donor and its surface structure also favors microbial adhesion and growth.The result indicates that Pseudomonas sp is the main bacteria in the corncob-based denitrification system.