反硝化除磷工艺实现亚硝酸盐积累的参数优化

为促进反硝化除磷与厌氧氨氧化工艺的耦合,实现污水氮、磷的同步高效去除,构建序批式反应器(Sequencing batch reactor,SBR),优化了反硝化除磷工艺实现亚硝酸盐积累的工艺参数.SBR在厌氧-缺氧-微好氧运行条件下,缺氧段投加模拟硝酸盐工业废水逐步实现了反硝化除磷过程的亚硝酸盐积累.结果表明,经过142d的培养驯化,在进水C/P比为55时,缺氧段引入NO₃^--N浓度为23mg/L时,亚硝酸盐积累率为51.01%,NO₃^--N→NO₂^--N转化率为40.22%,硝酸盐去除率为72.14%,PO₄^3--P去除率最高达88.17%.出水COD浓度低于25mg/L,COD去除率维持在90%以上.微生物群落结构分析表明,拟杆菌门(Bacteroidetes)、变形菌门(Proteobacteria)、绿弯菌门(Chloroflexi)、酸杆菌门(Acidobacteria)为系统内优势菌门.通过参数优化实现了聚磷菌的驯化,Candidatus Accumulibacter为代表的反硝化聚磷菌丰度增加(累积丰度由1.49%增加到5.08%),以Candidatus Competibacter为代表的反硝化聚糖菌丰度增加更为明显(累积丰度由1.02%增加到15.49%),聚磷菌与聚糖菌的共同作用有利于实现除磷过程的亚硝酸盐累积.

Parameter optimization for the achievement of nitrite accumulation by denitrifying phosphorus removal process

To promote the coupling of denitrification phosphorus removal and anaerobic ammonia oxidation process, and achieve simultaneous efficient removal of nitrogen and phosphorus from wastewater, a sequencing batch reactor (SBR) was constructed to optimized the operational parameters for the nitrite accumulation by denitrifying phosphorus removal process. Under anaerobic-anoxic-microaerobic operational conditions, SBR gradually realized nitrite accumulation during denitrifying phosphorus removal process by feeding synthetic nitrate industrial wastewater in the anoxic section. The results showed that after 142 days of cultivation and domestication, when the influent C/P ratio of 55 and the nitrate concentration in the anoxic section was 23mg/L, the nitrite accumulation rate achieved 51.01%, the NO₃^--N→NO₂^--N transformation rate was 40.22%, nitrate removal rate was 72.14% and the highest removal rate of PO₄^3--P was 88.17%. The effluent COD concentration was lower than 25mg/L, and COD removal rate was maintained above 90%. Analysis of the microbial community structure showed that Bacteroidetes, Proteobacteria, Chloroflexi and Acidobacteria were the dominant phylum in the system. Through parameter optimization, the abundance of denitrifying phosphorus accumulating organisms represented by Candidatus Accumulibacter increased (the cumulative abundance increased from 1.49% to 5.08%), and a more remarkable increase in the abundance of glycogen accumulating organisms represented by Candidatus Competibacter (from 1.02% to 15.49%). The combined effects of phosphorus accumulating organisms and glycogen accumulating organisms contributed to the accumulation of nitrite in the phosphorus removal process.