城市污水生化处理后水中溶解性有机物的特性研究

Research on characterization of dissolved organic matters in sewage after biological treatment

采用XAD树脂分离技术和超滤膜法对青岛市某城市污水处理厂生物化学处理后出水中溶解性有机物(DOM)进行了分类分离,研究了出水中DOM的亲疏水特性及分子量分布规律,探讨了各类DOM组分与芳香度之间的关系.研究结果表明,在DOM中,酸性物质(包括过渡亲水酸性物质和疏水酸性物质)所占比例最高,占总溶解性有机碳(DOC)的79.8%,疏水非酸性物质的芳香度最高,并依疏水酸性物质、过渡亲水酸性物质、亲水性物质的顺序递减,且羰基、羧基、羟基、脂类对芳环的取代程度表现为亲水性物质<过渡亲水酸性物质<疏水非酸性物质<疏水酸性物质;该污水处理厂二级出水中的DOM以小分子量有机物(相对分子质量小于1kDa)为主,其占总DOC的59.13%,表明水中腐殖酸类等难降解有机物质含量较高,增加了消毒副产物的生成势.因此,若该种水体需要深度处理时,应重点考虑提高对腐殖酸类等难降解有机物质的处理程度,确保回用水水质的安全性.

The dissolved organic matters（DOM） in secondary effluent from some municipal wastewater treatment plant were classified and separated by applying the XAD resin separation and ultrafiltration membrane.The hydrophilic/hydrophobic characteristics,molecular weight（MW） distribution and the relationship between the DOM composition and aromaticity were also investigated.The results showed that the acidic substances（including the transition hydrophilic acid and hydrophobic acid） were the highest fractions in the secondary effluent DOM,with 79.8% of total dissolved organic carbon（DOC）.Non-acid hydrophobic had the highest aromaticity,and the aromaticity decreased as follows：HPITPI-AHPO-AHPO-N.While the replacement extent of the aromatic ring by carbonyl,carboxyl,hydroxyl and lipid was： HPITPI-AHPO-NHPO-A.The secondary biological effluent DOM was mainly characterized with small MW organic matters（MW1 kDa）,which accounted for 59.13% of the total DOC.Further investigations showed that the refractory organics（mainly humic acids）,which were the precursor of the disinfection by-products,could not be effectively removed.Therefore,if the advanced treatment is needed,the removal of humic acids should be mainly considered in advanced treatment processes to ensure the safety of the treated water.