School of Chemical Engineering, Northeast Electric Power University, Jilin 132012, China.
School of Chemical Engineering, Northeast Electric Power University, Jilin 132012, China.
Sci Total Environ. 2021 Aug 1;780:146505. doi: 10.1016/j.scitotenv.2021.146505. Epub 2021 Mar 17.
During biological wastewater treatment, ferric salt (Fe) usually serves as an inorganic flocculant to improve the agglomeration and sedimentation of suspended solids, and thus the removal efficiency of pollutants to meet the increasing strictly regulated wastewater discharge standards. In this study, we investigated the effects of Fe on the removal efficiencies of pollutants, sludge properties, dominant flora and metabolic pathways of bacterial community in a classical anaerobic-anoxic-oxic (AO) process. The results showed that a Fe concentration lower than 10 mg·L could improve the removal efficiencies of chemical oxygen demand (COD) and total nitrogen (TN), while an inhibition effect was exerted at concentration higher than 10 mg·L. The maximum removal efficiencies of COD and TN were 97% and 89%, respectively, under the critical Fe concentration of 10 mg·L. Total phosphorous (TP) removal was constantly positively correlated with Fe concentration, due to the enhanced adsorption of phosphorus on activated sludge with the increase of surface roughness. Thauera displayed the highest relative abundance, and certain bacteria in Proteobacteria, Dehloromonas and Candidatus-Competibacter exhibited good adaptability to high concentration of Fe. In the context of metabolic collaterals, the most abundant functional gene families were identified to be Carbohydrate Metabolism, Amino Acid Metabolism, Cell Motility, Membrane Transport, and Replication and Repair. This study provides an extensive mechanistic insight into the impact of Fe on the AO process, which is of fundamental significance to exploit the contributions of inorganic salts to biological wastewater treatment.
在生物废水处理过程中，铁盐（Fe）通常用作无机絮凝剂，以提高悬浮固体的聚集和沉降能力，从而提高污染物的去除效率，以满足日益严格的废水排放标准。在这项研究中，我们研究了 Fe 对污染物去除效率、污泥性质、优势菌群和细菌群落代谢途径的影响，该研究采用了一种经典的厌氧-缺氧-好氧（AO）工艺。结果表明，Fe 浓度低于 10mg·L 时可以提高化学需氧量（COD）和总氮（TN）的去除效率，而浓度高于 10mg·L 时则会产生抑制作用。在临界 Fe 浓度为 10mg·L 时，COD 和 TN 的最大去除效率分别达到 97%和 89%。TP 的去除率与 Fe 浓度呈正相关，这是由于活性污泥表面粗糙度的增加，磷的吸附增强。Thauera 的相对丰度最高，而变形菌门、脱氯单胞菌属和拟杆菌门中的某些细菌对高浓度 Fe 具有良好的适应性。在代谢旁支方面，鉴定出最丰富的功能基因家族是碳水化合物代谢、氨基酸代谢、细胞运动性、膜转运和复制与修复。这项研究深入了解了 Fe 对 AO 工艺的影响，这对于利用无机盐对生物废水处理的贡献具有重要意义。
