城市污水处理过程中不同形态氮类营养物的转化特性

Transformation characteristics of different forms of nitrogen nutrients in process of wastewater treatment

针对不同形态氮类营养物在城市污水处理系统中迁移转化机理尚不明确这一问题,通过现场监测和实验室模拟分析,研究不同形态氮类营养物在整个城市污水处理系统(A/A/O工艺)中的转化特性。研究结果表明,在原污水总氮中溶解态氮和颗粒态氮比例相当,浓度分别为39.28 mg/L和41.24 mg/L,无机氮是溶解态氮的主要成分,比例占93.2%(36.61 mg/L),而有机氮含量极少,仅为2.67 mg/L。在颗粒态氮中有机氮比重很大,约占96.58%(39.83 mg/L)。在整个一级处理过程中溶解态氮变化量很小,而颗粒态有机氮减少了45%,总氮降低主要是由于颗粒态有机氮通过沉淀作用去除而实现的。现场监测和模拟实验结果表明,溶解性有机氮在厌氧区和缺氧区中由于被厌氧微生物降解而大幅度减少,而在好氧区却有一定程度的增加。二级出水中的氮主要还是以无机氮为主,可通过进一步优化工艺参数来强化系统硝化/反硝化作用,去除污水中残留的无机氮。

The aim of this study was to investigate the transformation process of different forms of nitrogen nutrients by filed measurement and simulate test in the whole city sewage treatment（ A/A /O） system. The study showed that influent dissolved nitrogen and particulate nitrogen proportion were almost the same,concentrations of 39. 28 mg/L and 41. 24 mg/L,respectively. Dissolved nitrogen was mainly composed of dissolved inorganic nitrogen,which portion constituted 93. 2%（36. 61 mg/L）,but dissolved organic nitrogen concentration was very low（2. 67 mg/L）. The particulate organic nitrogen portion constituted 96. 26% of the particulate nitrogen. Dissolved nitrogen changes was very small in the process of the whole primary treatment,but particulate organic nitrogen decreased 45%. Particulate organic nitrogen was removed due to precipitation,which resulted in lower total nitrogen. Filed measurement and simulate test showed that dissolved organic nitrogen was significantly reduced by anaerobic microbial degradation in the anaerobic and anoxic compartments of the secondary treatment,whereas a slightly increase of dissolved organic nitrogen concentrations was observed in the aerobic compartment.Secondary effluent nitrogen mainly composed of inorganic nitrogen,through the further optimization of process parameters,we can enhance system nitrification/denitrification to remove the residue of inorganic nitrogen in the wastewater.