生物膜系统中部分反硝化实现特性

Characteristics of Partial Denitrification in Biofilm System

以移动床生物膜反应器(moving-bed biofilm reactor,MBBR)为例,考察生物膜系统中部分反硝化NO^(-)_(2)-N积累特性,并通过耦合厌氧氨氧化验证生物膜系统中部分反硝化耦合厌氧氨氧化(partial denitrification with anaerobic ammonium oxidation,PD+ANAMMOX)工艺的可行性.结果表明,在C/N为3.0,填充率为20%的条件下,经过40 d的富集培养,实现部分反硝化,NO^(-)_(2)-N积累率达(69.38±3.53)%;接种生物膜NO-3-N还原酶(nitrate reductase,NAR)活性为0.03μmol·(min·mg)^(-1),NO^(-)_(2)-N还原酶(nitrite reductase,NIR)活性为0.18μmol·(min·mg)^(-1),富集培养后生物膜NAR活性增至0.45μmol·(min·mg)^(-1),NIR活性降至0.02μmol·(min·mg)^(-1),从酶学角度验证了部分反硝化实现;高通量测序结果显示,Thauera属从0.3%增加至37.27%,在微生物群落中占主导地位,该菌属被认为是部分反硝化过程的主要功能菌.随后与厌氧氨氧化耦合,出水总氮达(6.41±1.50)mg·L^(-1),总氮去除率达(88.16±2.71)%,证明了生物膜系统中PD+ANAMMOX的可行性及稳定性.

As an intermediate form of microbial denitrification,nitrite serves as a key substrate for anaerobic ammonium oxidation( ANAMMOX). This study investigated the partial dentification( PD) characteristics and the coupling feasibility of PD + ANAMMOX in the biofilm system,using a moving bed biofilm reactor which was operated for 120 days. After 40 days of operation with a C/N ratio of 3. 0 and filling fraction of 20%,the nitrate-to-nitrite transformation ratio( NTR) reached( 69. 38 ± 3. 53) %,and enzymatic assays indicated that the activities of nitrate reductase( NAR) had increased from 0. 03 to 0. 45 μmol·( min·mg)^(-1) while the activities of nitrite reductase( NIR) had decreased from 0. 18 to 0. 02 μmol·( min·mg)^(-1). Illumina high-throughput sequencing analysis revealed that the proportion of genus of Thauera bacteria to total microorganism increased from 0. 3%( d1) to 37. 27%( d64). Finally,the effluent had a total nitrogen( TN) concentration of( 6. 41 ± 1. 50) mg·L^(-1),indicating a total nitrogen removal ratio of( 88. 16 ±2. 71) % and confirming the feasibility of PD + ANAMMOX in the biofilm system.