3DBER系统功能强化与协同作用机制研究

针对污水厂二级生物处理出水C/N低且可生化性差、深度脱氮需外加碳源等问题，结合污水资源化对二级处理出水深度去除TN、TP和微污染物的技术需求，通过改变传统三维电极生物膜工艺（3DBER）的填料组成，构建了强化反硝化脱氮、并具备同步除磷、除微污染物（以邻苯二甲酸二丁酯（DBP）、邻苯二甲酸（2-乙基已基）酯（DEHP）为例，用PAEs表示）功能的3DBER多功能复合反硝化系统，探讨了3DBER工艺强化脱氮同步实现除磷、除微污染物复合功能的技术途径，并从工艺性能、微生物种群分布等角度，深入解析了实现复合功能的技术方法与微观作用机制.结果表明，硫/铁复合功能填料是实现低C/N二级生物处理出水深度脱氮、除磷、除微污染物的关键因素，多功能复合反硝化系统脱氮效率比传统3DBER工艺平均提高20%左右，TP去除率可达80%，PAEs去除率在90%以上.化学计量学和分子生物学技术的分析表明，复合系统脱氮、除磷过程中在微生物生态、电子供体补偿和酸碱度平衡等方面存在协同促进作用.其中，脱氮功能来自异养与多种自养反硝化共同作用，除磷的关键是海绵铁的持续腐蚀，PAEs的去除过程则是吸附、电化学氧化与生物降解协同作用的结果.

Performance enhancement and synergy mechanism in a 3DBER multifunctional system

The effluent from the secondary biological treatment of sewage plant usually has a low C/N ratio and low biodegradability, additional carbon sources should be added in its deep denitrification process. To address this problem and meet the sewage recycling technology demand for the deep removal of total nitrogen (TN), total phosphorus (TP), and micro-pollutants in the secondary treatment effluent, a multifunctional composite denitrification system based on three-dimensional biofilm electrode reactor process (3DBER) was developed in this study by changing the composition of filler materials in the traditional 3DBER. This new system could achieve enhanced denitrification and simultaneous removal of phosphorus and micro-pollutants (dibutyl phthalate (DBP) and o-benzene Dicarboxylic acid (2-ethylhexyl) ester (DEHP), which were represented by PAEs). The technical approaches of the multifunctional 3DBER process and the corresponding micro-action mechanisms for pollutant removal were examined from the perspectives of process performance and microbial population distribution. The results showed that the sulfur/iron composite functional filler was a key factor for achieving deep denitrification and simultaneous removal of phosphorus and micro pollutants for the secondary biological treatment effluent with a low C/N ratio. The denitrification efficiency of the multifunctional composite system increased by about 20% compared with the traditional 3DBER process, the simultaneous TP removal rate reached 80% and the PAEs removal rate were above 90%. The analysis from chemometrics and molecular biology technologies showed that there was a synergistic promotion effect among microbial ecology, electron donor compensation, and pH balance in the process of denitrification and phosphorus removal. The function of nitrogen removal was due to the joint action of heterotrophic and various autotrophic denitrification, and the key to phosphorus removal was the continuous corrosion of sponge iron. The removal of PAEs was the result of the synergistic effect of adsorption, electrochemical oxidation, and biodegradation. The results can provide theoretical and technical guidance for developing advanced treatment processes for the simultaneous denitrification, phosphorus removal, and micro pollutant removal from secondary biological treatment effluent.