难降解石化干法腈纶废水物化-生化 耦合处理技术研究

采用物化-生化耦合处理难降解石化干法腈纶废水,开展了以多技术协同O3高级氧化与多格室A/O型膜生物(MBR)反应器为核心工艺的小试与中试试验研究。结果表明,物化-生化技术的合理耦合可显著提高石化干法腈纶废水处理中化学耗氧量(COD)、氨氮和总氮(TN)去除效果;MBR-O3氧化-曝气生物滤池(BAF)集成试验工艺稳定运行工况下,其COD、氨氮和TN去除率分别可以达到90.0%、95.0%和80.0%,出水平均浓度可分别控制在100.0 mg/L、5.0 mg/L和35.0 mg/L以下。另外,由于石化干法腈纶废水水质缺少一定的可生化有机碳源以及丙烯腈低聚物和含氮杂环类有机物的难生物降解性,因此在生物脱氮过程中,有机氮向无机氨氮转化的氨化步骤限制了整体工艺脱除总氮的效果。     

Characteristics of extracellular fluorescent substances of aerobic granular sludge in pilot-scale sequencing batch reactor

The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor (SBR), and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances (EPS) of sludge samples were extracted and analyzed during the granulation and storage process. The results show that the contents of protein and EPS increase along with the granulation process, while polysaccharides remain almost unchanged. The content of protein in EPS is almost two-fold larger than that of polysaccharides in granular sludge cultivated with municipal wastewater. Moreover, some of the granules disintegrate during storage, corresponding to the decrease of protein contents in EPS. Three peaks are identified in three-dimensional excitation emission matrix (EEM) fluorescence spectra of the EPS in the aerobic granules. Two peaks (A and B) are attributed to the protein-like fluorophores, and the third (peak C) is related to visible fulvic-like substances. Peak A gradually disappears during storage, while a new peak related to ultraviolet fulvic acid (peak D) is formed. The formation and the stability of aerobic granules are closely dependent on the quantity and composition of EPS proteins. Peak C has no obvious changes during granulation, while the fulvic-like substances present an increase in fluorescence intensities during storage, accompanied with an increase in structural complexity. The fulvic-like substances are also associated with the disintegration of the aerobic granules.