浮床植物净化生活污水中N、P的效果及N_2O的排放

Nitrogen and phosphorus removal and N_2O emission from domestic sewage in floating-bed plant systems

在温室内采用浮床无土栽培技术,研究了黑麦草(Lolium mutliflorum)、水芹(Oenanthe javanica)和香根草(Vetiveria Zizanioides)3种植物对生活污水中N、P的去除效果及净化过程中N2O的排放特征。结果表明,浮床植物系统对生活污水的TN、NH4+-N和TP具有良好的净化效果。同对照系统相比,浮床黑麦草、水芹和香根草系统对TN的平均去除率分别提高了26.2%,22.9%,4.1%;对NH4+-N的去除率分别提高了31.4%,14.5%,3.0%;对TP去除率分别提高了33.1%,54.2%,15.5%。净化周期内,浮床各系统的TN、NH4+-N和TP浓度随着污水停留时间的延长直线下降,而NO3-N浓度却因系统内硝化强度大于反硝化强度而产生了累积;植物的存在明显的促进了浮床系统的N2O排放,浮床黑麦草、水芹、香根草和对照系统N2O的平均排放通量分别为174.44μg/(m2.h),82.19μg/(m2.h),112.49μg/(m2.h)和44.81μg/(m2.h)。浮床系统N2O排放通量的日变化呈现出夜间下降而白天增加的规律,与温度的昼夜变化规律基本相同,表明温度的升降直接影响了N2O的生成及排放。

Removal efficiency of nitrogen, phosphorus and N20 emission from domestic sewage in floating-bed system with Lolium mutliflorum, Oenanthe javanica and Vetiveria Zizanioides were investigated in greenhouse. Results showed that all three plants had good removal efficiencies of total nitrogen （TN）, ammonia-nitrogen （NH4 -N） and total phosphorus （TP） from domestic sewage in the floating-bed system. In comparison with the none-plant system, the three plants increased averagely the TN removal rate by 26.2% ,22.9% and 4.1% , the NH4 -N removal rate by 31.4%, 14.5% and 3.0% ,and the TP removal rate by 33.1% ,54.2% and 15.5%, respectively. With retention time prolonged, the concentrations of TN, NH4 -N and rip of domestic sewage were obviously reduced in all floating-bed systems, however the NO3-N concentrations were gradually accumulated due to the stronger nitrification than denitrification. The plants in floating-bed system increased significantly the N2O flux, which was 174.44 μg/（m^2·h,82.19 μg/（m^2·h ,112.49μg/（m^2·h） and 44.81μg/（m^2·h, respectively, for the Lolium mutliflorum, Oenanthe javanica, Vetiveria Zizanioides and none-plant floating-bed systems. The N2O flux from all floating-bed followed the change pattern of temperature, suggesting temperature. systems increased during the day but decreased during night that the N2O production and emission was affected by the