3D-EEMs和PARAFAC解析土壤渗滤处理污水厂二级出水研究

利用三维荧光光谱（3D-EEMs）和平行因子分析（PARAFAC）的方法研究了土壤渗滤处理污水厂二级出水中氮、磷及溶解性有机物（DOM）的垂直分布特征。试验在一个中试规模的土壤渗滤系统中进行，反应器自上而下每隔30 cm设置一个采样口，采集的样品通过PARAFAC识别出系统不同点位的DOM具有4个荧光组分，包括2个类腐殖质物质（C1，C2）、2个类蛋白物质（C3，C4）。对荧光组分浓度得分F_max分析得出，C4代表的类色氨酸比其他3类物质更易于降解，即类色氨酸最易降解，其次为类富里酸、类胡敏酸类物质、类蛋白物质。四种组分的F_max变化幅度都以在0~30 cm处最大，表明此处生化反应最为剧烈，DOM的迁移转化速率最大。运用PARAFAC、主成分分析（PCA）和聚类分析（CA）等手段，可以揭示土壤渗滤系统中DOM的来源和不同深度的变化规律。土壤渗滤系统在4 L·d-1的低负荷条件下处理污水处理厂二级出水，对TN和NO3-N的去除是不利的，后续可以耦合反硝化滤池等工艺强化反硝化脱氮，进一步提高氮素的去除率。土壤对磷的吸附尚未达到饱和的状态，保持了较高的TP去除效率。

Analysis of Two Stage Effluent from Sewage Treatment Plant by 3D-EEMs and PARAFAC

The vertical distribution characteristics of nitrogen, phosphorus and DOM in secondary effluent of soil infiltration WWTP were studied by 3D-EEMs and PARAFAC. The experiment was carried out on a pilot-scale soil infiltration system with a sampling port at 30 cm intervals from top to bottom. The collected samples were identified by PARAFAC model as having 4 fluorescent components at different points in the system, including two humus substances (C1, C2) and two protein substances (C3, C4) respectively. Fmax analysis showed that the tryptophan represented by C4 was more easily degraded than other three kinds of substances, that is, tryptophan was the most easily degraded, followed by fulvic acid, humic acid and protein-like substances. The Fmax variation of the four components was the largest at 0~30 cm, which showed that the biochemical reaction was the most intense and the migration and transformation rate of DOM was the highest. The source of DOM in soil infiltration system and the variation law of DOM in different depths could be revealed by means of PARAFAC, PCA and CA. Soil infiltration system was unfavorable for TN and nitrate removal in treating secondary effluent of sewage treatment plant under 4 L·d-1 low load condition. The subsequent denitrification processes such as denitrification filter could be coupled to enhance denitrification and nitrogen removal rate. The adsorption of phosphorus on soil had not yet reached saturation state, and had maintained a high TP removal efficiency.