改进UCT工艺强化城镇污水脱氮除磷实例研究

Case Study on Strengthening Nitrogen and Phosphorus Removal of Urban Sewage by the Improved UCT Process

目前城镇污水处理厂大多存在运行能耗高、污水处理效能低、脱氮除磷能力不足等问题,污水处理提质增效迫在眉睫。以出水可稳定达到一级A标准的南京市某污水厂改进UCT工艺为工程实例,通过全流程水质监测与微生物群落结构分析,探究优化工艺设计与运行对强化脱氮除磷的影响。结果表明,通过合理设置分段进水、多点回流比例和回流点位,UCT工艺可取得较好的脱氮效果,TN去除率可达到79.23%和82.29%;延长HRT、降低厌氧区进水浓度、增加内回流点数均有利于多种脱氮途径协同作用,尤其厌氧氨氧化脱氮贡献可提高7.48%;但强化生物脱氮与除磷条件之间存在拮抗作用。微生物群落结构分析显示,HRT的增长及内回流点的增加有利于提高微生物多样性,同时能使浮霉菌门(Planctomycetes)占优,丰度为29.48%~50.67%,好氧池硝化螺旋菌属(Nitrospira)受到抑制。研究结果可为国内现有污水处理厂提质增效提供工艺改进和运行优化方面的指导和依据。

The current urban sewage treatment plants have some problems such as high operating energy consumption,low sewage treatment efficiency,and insufficient nitrogen and phosphorus removal.Therefore,it is urgent to improve the quality and efficiency of wastewater treatment.A sewage treatment plant in Nanjing was used as an engineering case,which improved the UCT process and the effluent can stably reach the Grade A standard.The influence of its process design and operating parameters on the enhanced nitrogen and phosphorus removal was discussed by the whole process water quality monitoring and microbial community structure analysis.The results showed that the UCT process can achieve a better nitrogen removal effect by reasonably setting the proportion of sublevel inlet water,multi-point reflux,and reflux point,and the TN removal rate can reach 79.23%and 82.29%.Prolonging HRT,decreasing influent concentration in anaerobic zones,and increasing internal reflux points were also beneficial to the synergistic effect of multiple denitrification approaches,especially the contribution of nitrogen removal by anammox can be increased by 7.48%.However,there was an antagonism between biological nitrogen and phosphorus removals.The analysis of microbial community structure showed that the increased HRT and added internal reflux points contributed to improving the microbial biodiversity,making Planctomycetes dominate with the abundance ranging from 29.48%to 50.67%,and inhibiting Nitrospira in aerobic tanks.The research results are expected to provide guidance and a basis for process improvement and operation optimization to improve the quality and efficiency of existing domestic sewage treatment plants.