进水C/N对SNEDPR系统脱氮除磷的影响

为了解同步硝化内源反硝化系统(SNEDPR)脱氮除磷性能,采用延时厌氧(180 min)/低氧(溶解氧0. 5～2. 0 mg·L~(-1))运行的SBR反应器,以人工配置的模拟废水为处理对象,先采用恒定进水C/N(为10),以实现SNEDPR的启动和聚磷菌(PAOs)的富集培养,再调控进水C/N值(分别为10、7. 5、5和2. 5),考察不同C/N对系统的脱氮除磷性能的影响.结果表明,当进水C/N为10,可实现SNEDPR的启动与深度脱氮除磷,出水PO3-4-P和总氮(TN)浓度分别平均为0. 1 mg·L~(-1)和8. 1mg·L~(-1),PO3-4-P去除率、TN去除率和SNED率平均值分别为99. 79%、89. 38%和58. 0%.当进水C/N由5提高至10时,系统维持良好的脱氮除磷性能,释磷量(PRA)和SNED率分别由16. 0 mg·L~(-1)和48. 0%提高至24. 4 mg·L~(-1)和69. 2%;当C/N为10时,TN和PO3-4-P去除率最高达94. 5%和100%;当C/N为2. 5时,系统失去脱氮、除磷性能,PRA和SNED率仅为1. 36 mg·L~(-1)和10%.在系统稳定运行阶段(C/N为10、7. 5和5),SNED率达85. 9%,出水NH_4~+-N、NO-x-N和PO3-4-P浓度平均为0、8. 1和0. 1 mg·L~(-1).

Effect of Influent C/N Ratio on the Nutrient Removal Characteristics of SNEDPR Systems

To determine the performance of nitrogen and phosphorus removal within a simultaneous nitrification endogenous denitrification system (SNEDPR), an extended anaerobic/low aerobic (dissolved oxygen:0.5-2.0 mg·L^-1)-operated sequencing batch reactor (SBR) was fed with simulation wastewater. The SBR was initiated under a constant influent C/N ratio of 10, with the simultaneous enrichment of polyphosphate-accumulating organisms (PAOs). It was then investigated at different influent C/N ratios of 10, 7.5, 5, and 2.5. The experimental results indicated that, when the influent C/N ratio was 10, SNEDPR could be successfully started up. The effluent PO₄^3--P and total nitrogen (TN) concentrations were 0.1 mg·L^-1 and 8.1 mg·L^-1. PO₄^3--P efficiency, TN efficiency, and SNED efficiency were 99.79%, 89.38%, and 58.0%, respectively. When the influent C/N ratio increased from 5 to 10, the nitrogen and phosphorus removal performance of the system improved with PRA, and SNED efficiency increased from 16.0 m·L^-1 and 48.0% to 24.4 mg·L^-1 and 69.2%, respectively. When the C/N ratio was 10, the TN and PO₄^3--P removal efficiencies increased to 94.5% and 100%, respectfully. When the C/N ratio was decreased to 2.5, the nitrogen and phosphorus removal performance of the system decreased. The PRA and SNED efficiencies were only 1.36 mg·L^-1 and 10%, respectively. During the stable phase of the system (C/N ratio were 10, 7.5 and 5), SNED efficiency reached to 85.9%, with the average effluent concentration of NH₄⁺-N, _x^--N, and PO₄^3--P being 0.0, 8.1, and 0.1 mg·L^-1, respectively.