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传统厌氧消化基质转化慢,甲烷产率和能量回收效率较低.本研究模拟厌氧酸化产生的短链脂肪酸(SCFAs)废水,在批式条件下,利用单室无膜微生物电解池辅助厌氧消化(MEC-AD)产甲烷,考察不同外加电压(0.4 V、0.6V、0.8 V)对底物降解、甲烷产生和能量回收效率的影响.结果表明,进水化学需氧量(C OD)浓度约为7 000 mg/L时,COD的平均去除负荷由AD的(3.34±0.09)k g m-3 d~(-1)提高到MEC-AD的(6.86±0.04)kg m-3 d~(-1)(外加0.8 V),增加了1.06倍.外加电压与脂肪酸组分的降解呈正相关,即随着外加电压的升高,底物各SCFA降解速率加快,此时相应的甲烷含量、产量明显提高.当外加电压为0.8 V时,混合脂肪酸中乙酸、丙酸及丁酸的降解速度较AD分别提高了98.25%、107.14%、54.21%,甲烷的含量达90.11%;甲烷的产率为2.63 L L~(-1) d~(-1),较AD提高了157.84%.以基质化学能、电能和产生的甲烷来计算总能量回收效率,其中AD为73.51%;加电0.4 V、0.6 V、0.8 V时分别为93.44%、88.99%、93.41%.综合脂肪酸降解、甲烷产生及能量回收情况,确定外加0.8 V为最优条件.循环伏安扫描分析发现,与AD相比,MEC-AD在-0.3V处存在明显产甲烷还原峰.高通量测序结果显示,MEC-AD中阳极优势菌群为Methanosaeta sp.和Geobacter sp.,其相对丰度比分别为36.43%和13.35%;而AD中相应比例仅为24.46%和0.99%.由此可知MEC-AD中可能存在直接的种间电子传递(DIET)产甲烷途径,该途径是甲烷含量和产量提升的重要原因.综上,以微生物电解池辅助厌氧消化能有效促进底物降解,且获得高纯度、高产量的甲烷,具有良好的应用前景.
Traditional slow release of anaerobic digestion matrix, methane yield and energy recovery efficiency is low.This study simulated the anaerobic acidification of short chain fatty acids (SCFAs) wastewater, under batch conditions, the use of single-chamber membrane-free microbial cell auxiliary The effects of different applied voltages (0.4 V, 0.6 V, 0.8 V) on the substrate degradation, methane production and energy recovery efficiency were investigated.The results showed that the chemical oxygen demand (C OD ) At a concentration of about 7 000 mg / L, the average COD removal load increased from (3.34 ± 0.09) kg m-3 d -1 to (6.86 ± 0.04) kg m-3 d -1 (plus 0.8 V), an increase of 1.06 times.The applied voltage was positively correlated with the degradation of fatty acid components, that is, with the increase of applied voltage, the degradation rate of each SCFA substrate was accelerated, and the corresponding methane content , And the yield of acetic acid, propionic acid and butyric acid increased by 98.25%, 107.14% and 54.21%, respectively, and the methane content reached 90.11% when the applied voltage was 0.8 V. The methane production Rate of 2.63 LL ~ (-1) d ~ (-1), which is 157.84% higher than that of AD.The total energy recovery efficiency was calculated from the matrix chemical energy, electric energy and methane produced, of which AD 73.51%, respectively. Under the conditions of 0.4 V, 0.6 V and 0.8 V, the values were 93.44%, 88.99% and 93.41%, respectively.Under the conditions of total fatty acid degradation, methane production and energy recovery, 0.8 V was the optimal condition. It was found that there was a significant methane reduction peak at -0.3 V in MEC-AD compared with AD.High-throughput sequencing showed that the dominant anode population in MEC-AD was Methanosaeta sp. And Geobacter sp., And its relative abundance Compared to 36.43% and 13.35% respectively, while the corresponding proportions in AD were only 24.46% and 0.99%, indicating that direct DIET methanogens could exist in MEC-AD, Therefore, it is an important reason for the increase of production.Furthermore, using microbial cell-assisted anaerobic digestion can effectively promote substrate degradation and obtain high-purity and high-yield methane with good application prospects.