异养-自养耦合深度脱氮系统的生物脱氮性能研究

Biological Nitrogen Removal Performance of Heterotrophic-Autotrophic Coupling Deep Denitrification System

为探究低C/N〔ρ(CODCr)/ρ(NO^-3-N),下同〕水体的脱氮技术,分别以火山岩、火山岩/铁碳颗粒、火山岩/硫磺颗粒、火山岩/铁碳颗粒/硫磺颗粒作为填料构建R1、R2、R3和R4反应器,考察反硝化系统在不同C/N下的脱氮效果.结果表明:①随着进水C/N的降低,R1、R2和R3反应器的NO^-3-N去除率逐渐降低,R4反应器则是先升后降;在C/N为1.5~2.0、系统温度为30℃、进水pH为7.0±0.2、HRT(水力停留时间)为4.0 h、进水ρ(NO^-3-N)为30 mg/L时,R4反应器中NO^-3-N去除率最高,平均值为90.1%.②在R2反应器中,随着反应器的运行,铁碳颗粒自身氧化表面形成氧化膜,使得铁自养反硝化作用不断减弱,脱氮效率与R1反应器相近.③运行前期,R2和R4反应器保持着较高的ρ(NH^+4-N),随着反应器的运行,4个反应器的ρ(NH^+4-N)相当.④与R3反应器相比,R4反应器中不存在NO^-2-N的累积情况,同时铁自养过程产生的碱能被硫自养过程所消耗,系统pH更适合反硝化菌生存.研究显示,C/N为1.5~2.0时,异养-铁-硫自养反硝化系统可提供充足的电子供体,减少对有机碳源的依赖,保证了稳定高效的脱氮效果.

To study denitrification technology in different low carbon and nitrogen ratio(C N)water,R1,R2,R3 and R4 reactors were constructed using volcanic rocks,volcanic rocks iron carbon particles,volcanic rocks sulfur particles,volcanic rocks iron carbon particles sulfur particles as fillers,and the efficiency of denitrification system under different C N conditions was investigated.The results showed that:(1)With the decrease of C N,the removal efficiency of nitrate nitrogen gradually reduced of R1,R2 and R3 and R4 reactor was to increased first and then decreased.When C N was 1.5-2.0,temperature was 30℃,pH was 7.0±0.2,hydraulic retention time(HRT)was 4.0 h,initialρ(NO^-3-N)was 30 mg L,R4 reactor nitrate removal efficiency was the highest,with an average removal efficiency of 90.1%;(2)In R2 reactor,with the reactor running,the iron carbon particles were oxidized the an oxide layer formed on the particle surface,which decreased the iron autotrophic denitrification,efficiency to a level similar to R1 reactor.(3)At the beginning,R2 and R4 reactors maintained a highρ(NH^+4-N),and thenρ(NH^+4-N)of the four reactors was equival;(4)Compared with R3 reactor,there was no accumulation of NO^-2-N in R4 reactor,and the alkali produced by the iron autotrophic process was consumed by sulfur autotrophic process,the system pH was more suitable for the survival of denitrifying bacteria.The research showed that when C N was 1.5-2.0,the heterotrophic-iron-sulfur autotrophic denitrification system provided sufficient electron donors and reduced the dependence on organic carbon source,ensured stable and efficient nitrogen removal.