硫磺/石灰石自养反硝化系统脱氮性能及N2O排放规律研究

Performance of Nitrogen Removal and N_2O Emission Law of Sulfur/Limestone Autotrophic Denitrification System

为了考察硫磺/石灰石自养反硝化系统的脱氮性能,并探究系统N_2O的产生和排放规律,采用均匀填充的上流式硫磺/石灰石生物滤池反应器,研究了2组HRT下,不同进水NO_3^--N浓度对系统脱氮效果的影响及N_2O的排放规律。结果表明,进水NO_3^--N浓度为(54.46±1.15)mg/L、HRT为2.5 h时,反应器容积负荷最大且对NO_3^--N去除率最高,可达99.93%,系统无NO_2^--N累积,出水N_2O低于0.86 mg/L;另外,研究发现NO_3^--N浓度随反应器高度增加而逐渐降低,N_2O浓度随着反应器下部NO_2^--N的富集逐渐增加,并随上部NO_2^--N的还原而逐渐减小;进水NO_3^--N浓度增大,N_2O累积量峰值点沿反应器高度逐渐上移,因此该系统仅能处理较低浓度NO_3^--N废水。

In order to investigate the performance of nitrogen removal of the sulfur/limestone autotrophic denitrification system, and to further research the production and emission of N2O, a uniformly filled sulfur/limestone biofilter reactor was used to study the influence of influent nitrate concentrations on the denitrification and N2O emission of the system at two HRTs. The results showed that,when HRT was kept at 2.5h, the concentration of NO3^--N was at（54.46±1.15）mg/L, the removal efficiency of NO3^--N reached up to 99.93%, NO2^--N was not accumulated, and N2O concentration in effluent was lower than 0.86 mg/L. The NO^--N concentration decreased with increasing of the reactor height, and the N2O production gradually increased with the increase of NO2^--N in the reactor, and then decreased with the decrease of NO2^--N. With the increase of NO3^--N concentration, the peak value of N2O accumulation increased gradually along the reactor height. As a result, the system can only treat the wastewater under low NO3^--N concentration.