生物基质对煤渣改良地下渗滤系统脱氮效果的影响

Effect of biological substrate on coal slag modified subsurface wastewater infiltration system nitrogen removal

地下渗滤系统(SWIS)对硝化、反硝化过程调控不灵活,导致其对氮的去除效果不够理想。组建了两套SWIS装置(1#装置:65~80cm段没有生物基质;2^#装置:65~80cm段添加生物基质),对沿程氮素、硝化和反硝化作用强度及氮还原酶活性进行分析。结果表明,两套装置均表现为硝化反应主要发生在20~60cm段,反硝化反应主要发生在60~80cm段。2^#装置的反硝化作用明显强于1#装置,因此其TN去除率高于1^#装置。硝化作用强度随深度增加而递减,反硝化作用强度随深度增加而递增。硝酸盐还原酶(NAR)活性随深度的增加而逐渐减弱,亚硝酸盐还原酶(NIR)活性随深度的增加先减弱后又增强。主要原因是2^#装置中添加了干化污泥作为生物基质,为反硝化作用补充了碳源,增强了脱氮能力。

Subsurface wastewater infiltration system(SWIS)is not flexible in the regulation of nitrification/denitrification process,which results in insufficient removal of nitrogen.Two SWIS devices(Device 1^#without biological substrate at 65-80 cm layer,while Device 2^#with biological substrate at 65-80 cm layer)were set up.Nitrogen,nitrification and denitrification intensities,and nitrogen reductases activities along the process were analyzed.Results showed that nitrification occurred at 20-60 cm layer,while denitrification at 60-80 cm layer for both two devices.The TN removal rate of Device 2^#was higher than that of Device 1^#,because denitrification intensity of Device 2^#was stronger than that of Device 1^#.Nitrification intensity decreased with the depth,but denitrification intensity increased with the depth.Nitrate reductase(NAR)activity decreased with the depth.Nitrite reductase(NIR)activity first decreased and then increased with the depth.The results could be explained that the biological substrate(dried sludge)added in Device 2^#supplemented the carbon source for the denitrification,and thus enhanced the nitrogen removal capacity.