城市污水处理厂出水作为再生水的主要水源, 其迥异的物质组成给受纳水体带来潜在环境风险。 全面掌握污水厂出水水体中有机物组成及结构信息, 将为污水厂提标改造及有毒有害物质排放标准的制定提供理论支撑。 采用傅里叶变换红外光谱和三维荧光光谱技术, 结合二阶导数光谱及区域积分分析方法, 对4个典型城镇污水处理厂(W1, W2, W3, W4)出水水体中颗粒态有机物(POM)与溶解态有机物(DOM)的物质组成及结构差异特征进行了分析。 结果显示: 污水处理厂出水中POM主要组分为脂肪类、 芳香类、 糖类及矿物盐, 而DOM主要由有机酸、 蛋白质、 多肽、 糖类及芳香类物质组成。 各污水处理厂出水水体POM中, W1芳香类物质较多而矿物盐类等颗粒较少, W2较W1含有更多的糖类物质, W3含较多脂类、 蛋白类及糖类, 而W4含有芳香类及羧酸物质的有机物较多。 水体DOM组成中, W1和W2成分较为类似, 主要为芳香性较高的大分子有机酸, 其含量分别占总有机物的73.9%和67.7%； W3与W4组成中蛋白、 多肽及糖类含量较高, 其中类蛋白物质分别占DOM总量的71.3%和53.5%。 研究结果表明, 采用傅里叶变换红外光谱结合二阶导数分析能很好识别不同污水处理厂出水水体中POM与DOM主要物质组成及结构差异, 同时利用区域积分方法对样品三维荧光光谱进行解析, 能更进一步定量分析不同来源样品物质组成特征。

The effluents from municipal wastewater treatment plant are believed to be a main water source of reclaimed water. However, the composition of organic matter in the effluents is unclear, which places a potential risk on the receiving waters body. Therefore, it is important to obtain the information on the composition and structure of organic matter in sewage plant, which will facilitate to improve the sewage treatment plants and to establishment the emission standard of harmful substances in wastewater effluent. Fourier transform infrared spectroscopy (FTIR) and three dimensional fluorescence excitation-emission matrix spectroscopy (EEM) were combined with second derivative infrared and fluorescence regional integration analysis to identify the composition and structure of particulate organic matter (POM) and dissolved organic matter (DOM) isolated from four sewage effluents (W1, W2, W3, and W4). The results showed that, POM in the effluents mainly consisted of aliphatic, aromatic, alkanes, carbohydrate and mineral salts, while DOM was primarily composed of carbohydrate, organic acid, proteins, peptides and hydrocarbons. As to POM in the effluents from the four sewage treatment plants, the sewage treatment plant W1 had higher aromatic substances and lower mineral salts; the sewage plant W2 had a higher carbohydrate content compared with the sewage plant W1; the sewage plant W3 had a higher aliphatic, protein and carbohydrate; and the sewage plant W4 was mainly composed of carboxylic acids and aromatic substances. As to DOM, W1 and W2 had a similar composition. The DOM in W1 and W2 comprised mainly the aromatic organic acid with high macromolecular, which accounts for 73.9% and 67.7% of the total DOM. However, W3 and W4 consisted mainly of proteins, peptides, carbohydrate and protein-like substances, which was responsible for 71.3% and 53.5% of the DOM. The results demonstrated that, FTIR spectroscopy coupled with second derivative analysis could be used to identify the main composition and structure differences between POM and DOM. EEM spectra combined with fluorescence regional integration can be applied to further quantitatively distinguish the composition differences of different effluent wastewater.