静压快速启动亚硝酸盐依赖型甲烷厌氧氧化反应

在序批式反应器(SBR)中接种污水厂厌氧池污泥和深层水稻土的1∶1混合污泥,在阶段性提升基质NO_2~--N浓度的条件下,考察静压条件对亚硝酸盐依赖型甲烷厌氧氧化(nitrite-dependent anaerobic methane oxidation,N-DAMO)反应快速启动过程的影响,并对N-DAMO反应的主导微生物的丰度变化进行分析.结果表明运行120 d后,常压(R1)和0.3 MPa静压(R2)条件下,都观测到了明显的N-DAMO现象,并且R2的NO_2~--N去除速率达到了36.90 mg·(L·d)~(-1),较R1提高了24%;其4 h内平均脱氮速率(以NO_2~--N计)达到0.10 mmol·(L·h)~(-1),比R1提高了186%.R2中富集得到的污泥粒径约为R1的2倍,比表面积更大,优化了污泥中甲烷的传质情况,有助于N-DAMO反应的进行,且R2污泥的N-DAMO比活性(以N/VSS计)达到了0.29 mg·(g·h)~(-1),是R1的2倍.此外,静压有助于N-DAMO功能微生物Candidatus Methylomirabilish oxyfera(M.oxyfera)的生长,实验结束时R2中M.oxyfera细菌16S rRNA基因的丰度比接种初期提高了22倍,是同阶段R1中的10倍.可见,提高静压能够有效促进N-DAMO反应的启动.

Rapid Start-up of a Nitrite-Dependent Methane Anaerobic Oxidation Reaction Under Static Pressure Conditions

The present study explores the effect of static pressure on the rapid start-up of a nitrite-dependent anaerobic methane oxidation (N-DAMO) process in lab-scale sequencing batch reactors (SBR). A mixture of anaerobic sludge and deep paddy soil with a volume ratio of 1:1 was used as inoculum and the influent of the nitrite (NO₂^--N) concentration was gradually increased to avoid a toxicity shock. The variation of the NO₂^--N removal performance and corresponding microbial characteristics were analyzed to evaluate the development of the N-DAMO process. After 120 days of operation, significant N-DAMO phenomena were observed in both the control SBR (R1) with normal pressure and pressurized SBR (R2) with a static pressure of 0.3 MPa. The NO₂^--N removal rate (measured by NO₂^--N) of R2 (36.90 mg·(L·d)^-1) was 24% higher than that of R1, while the average NO₂^--N removal rate in the first 4 h of the batch cycle in R2 (0.10 mmol·(L·h)^-1) was 186% higher than that of R1. The mean sludge size of R2 was~2-fold larger than that of R1. Sludge in R2 also has a bigger specific surface area, which improves the mass transfer rate of methane and the N-DAMO performance. The specific activity of N-DAMO (measured by N/VSS) reached 0.29 mg·(g·h)^-1 in the study period, which is approximately 2 times higher than that of R1. Moreover, the abundance of N-DAMO functional microbes Candidatus Methylomirabilish oxyfera (M. oxyfera) in R2 was 10-fold higher than that of R1. These results indicate that static pressure effectively accelerates the start-up of the N-DAMO process.