直流电场强化活性污泥法处理木质素废水的效能、污泥特性及群落结构研究

以溶解态木质素模拟废水为研究对象,考察了不同直流电场条件下活性污泥反应器(R1,无电流,悬浮污泥)、电极生物膜反应器(R2,电流I=10~60 mA,无悬浮污泥)与电极生物膜-活性污泥反应器(R3,I=10~60 mA,悬浮污泥)中木质素废水的处理效能、污泥生理特性(活菌比、木质素过氧化物酶(LiP)、三磷酸腺苷(ATP)等)、细胞膜磷脂脂肪酸组成及微生物群落结构的差异.结果表明:相同的外加电流下,R3的木质素去除率均高于R2(p0.05),其中,30 mA时达到最大值30.19%±0.47%,分别为R1、R2木质素去除率的2.01倍和1.46倍.反应器R2在20~40 mA时的总氮去除效果最好,达到71.96%±5.79%.分析R1、R3悬浮污泥发现,外加电流升高不改变悬浮污泥的活菌比(p0.05),木质素去除率受LiP酶活影响不大;与低电流(10~30 mA)相比,高电流(40~60 mA)下悬浮污泥中C15∶0 ANTEISO的含量降低,长链磷脂脂肪酸(C19、C20)的相对含量增加;R3悬浮污泥中Flavobacterium、Pseudomonas和Janthinobacterium等可降解木质素的菌属在10 mA外加电流的刺激下相对丰度均最高.在电极微生物方面,与R3相比,R2阴极微生物中具有反硝化能力的Methyloversatilis成为优势菌属,阳极微生物中存在更多具有电子传递能力的菌属(Pseudomonas、Ralstonia).冗余分析(RDA)表明,悬浮污泥中Mycobacterium(降解木质素的好氧细菌)丰度与电流(I)显著正相关(p0.05),与不饱和脂肪酸(UFA)显著负相关(p0.05).

The performance, sludge characteristics and microbial community in lignin wastewater treatment by direct current enhanced activated sludge approach

This study aims to investigate the effect of different intensity of direct currents (DC) on the removal of soluble lignin using three kinds of sequencing batch reactors (SBRs), and compared the sludge physiological characteristics (viability, LiP, ATP, etc.), phospholipid fatty acid (PLFA) of suspended sludge and microbial community structure between different kinds of SBRs. The three SBRs, referred to as Activated Sludge Reactor (R₁, activated sludge only, no current), Bio-electrode Reactor (R₂, I=10~60 mA, no activated sludge) and Bio-electrode Activated Sludge Reactor (R₃, activated sludge, I=10~60 mA), were operated with synthetic wastewater. Under the same DC intensity, the lignin removal in R₃ was always higher than that in R₂(p<0.05). The highest lignin removal (30.19%±0.47%) in R₃ was achieved at 30 mA and was 1.01 and 0.46 times higher than that in R₁ and R₂, respectively. The total nitrogen (TN) removal in R₂ reached up to 71.96%±5.79% at 20~40 mA, much higher than the other two reactors. The viability of suspended sludge was not affected by the increase of the currents (p>0.05) and LiP enzyme activity appeared to be irrelevant to lignin removal. PLFA analysis revealed that high currents (40~60 mA) led to the decrease of C15:0 ANTEISO content and increase of long chain fatty acids (C19, C20) in comparison with low currents (10~30 mA). High-throughput 16S rRNA sequencing verified that the highest abundance of lignin-degrading bacteria like Flavobacterium, Pseudomonas and Janthinobacterium were observed in R₃ under 10 mA current. For microorganisms on electrodes, a denitrifier-Methyloversatilis dominated the biofilm of cathode in R₂. Besides, more genera possessing the electron transfer ability were detected in biofilm of anode in R₂ (Pseudomonas, Ralstonia). RDA analysis indicated that Mycobacterium (one kind of lignin-degrading aerobic bacteria) in activated sludge were significantly positively correlated with current I (p<0.05) and negatively correlated with UFA (p<0.05).