基于改良ASM1的SNAD工艺启动和优化

Start-up and optimization of SNAD process based on modified ASM1

采用微氧升流式膜生物反应器(UMSB-MBR)启动同步亚硝化-厌氧氨氧化耦合异养反硝化(SNAD)工艺,拟通过构建数学模型实现工艺启动过程分析及其优化过程预测.结果表明:反应器历经厌氧氨氧化和全程自养脱氮(CANON)工艺后,通过引入有机碳源(C/N比为0.5)启动SNAD工艺(总氮去除率可达87.66%),并运用ASM1模型及实验数据成功建立SNAD工艺启动模型;通过模型分析发现,氮负荷(NLR)的增大(由0.24~1.88kg/(m^(3)·d)),适宜的溶解氧(DO)浓度(0.2~0.4mg/L)均有利于SNAD工艺的快速启动;通过模型预测发现,随着C/N比(由0.5~3.0)增大,反硝化菌(DNB)对厌氧氨氧化菌(An AOB)活性的抑制程度不断增强,造成脱氮主要途径由厌氧氨氧化向异养反硝化过程转化,综合考虑C/N比为1.5时SNAD工艺效能和微生物菌群配置处于最佳状态.

An up-flow micro-oxygen membrane bioreactor(UMSB-MBR)was utilized to start up the simultaneous nitrification,anaerobic ammonia oxidation coupling with heterotrophic denitrification(SNAD)process,and a mathematical model was planned to be built to realize the start-up process analysis and the optimization process prediction.The results showed that the SNAD process(the total nitrogen removal rate of 87.66%)started up successfully by inducing the carbon source(C/N ratio of 0.5)after anammox and completely autotrophic nitrogen removal(CANON)processes in the bioreactor,and the start-up model of the SNAD process was successfully built using the ASM1 model and experimental data;the model analysis revealed that the increase in the nitrogen loading rate(NLR)(from 0.24 kg/(m^(3)·d)to 1.88 kg/(m^(3)·d))and the suitable dissolved oxygen(DO)(0.2~0.4 mg/L)accelerated the start-up of the SNAD process;the model prediction revealed that the inhibition of anaerobic ammonia-oxidizing bacteria(AnAOB)from denitrifying bacteria(DNB)was strengthened with the increase in the C/N ratio(from 0.5 to 3.0),and shifted the major nitrogen removal pathway from anammox to heterotrophic denitrification process.From the comprehensive consideration,the appropriate C/N ratio should be chosen at 1.5 under which the process performance and distribution of the microbial flora could be at the best state of the SNAD process.