生物炭孔隙结构对市政污泥好氧发酵过程中甲烷释放的影响

Effect of Biochar Pore Structure on Methane Release during Aerobic Fermentation of Municipal Sludge

关键词:  市政污泥  好氧发酵  甲烷  生物炭  孔隙结构

Key words:  municipal sludge  aerobic fermentation  methane  biochar  pore structure

摘要:

为探究生物炭孔隙结构(孔径、孔容和比表面积)在市政污泥好氧发酵过程中对甲烷(CH₄)释放的影响，本研究分别以榉木生物炭(WB)、稻壳生物炭(RB)和玉米芯生物炭(CB)作为调理剂进行好氧发酵实验，并设置不添加生物炭的作为对照组(CK)，通过比表面积测试(BET)、气相色谱法(GC)、16S rRNA高通量测序技术和冗余分析(RDA)进行测定及分析。BET结果表明，WB和RB以微孔结构为主，分别占各自总孔隙结构的87.84%和73.72%，而CB以大孔结构为主，占比为89.94%。GC结果显示，与未加生物炭的CK相比，添加WB、RB和CB的市政污泥好氧发酵组的CH₄释放量分别减少41.83%、33.59%、8.20%。高通量测序结果表明，WB和RB通过提高发酵温度抑制了甲烷菌的相对丰度，而添加CB则使堆体的甲烷菌种类更丰富。RDA结果显示，生物炭孔径与CH₄释放速率呈正相关关系。综上可知，在本研究条件下添加以微孔结构为主的WB和RB对市政污泥好氧发酵过程中的CH₄减量化效果最佳。

Abstract:

In order to explore the effect of biochar pore structure (pore size,pore volume and specific surface area) on methane (CH₄) release during aerobic fermentation of municipal sludge,the beech Wood Biochar (WB),Rice husk Biochar (RB) and Corncob Biochar (CB) were used as conditioners for aerobic fermentation experiments in this study,and the Control Group (CK) without adding biochar was set up. The specific surface area test (BET),Gas Chromatography (GC),16S rRNA high-throughput sequencing technology and Redundancy Analysis (RDA) were used for determination and analysis.BET result showed that WB and RB were mainly microporous structures,accounting for 87.84% and 73.72% of the total pore structures,respectively,while CB was mainly macroporous structure,accounting for 89.94%. GC result showed that compared with the CK without biochar,the CH₄ release of municipal sludge aerobic fermentation group with WB,RB and CB decreased by 41.83%,33.59% and 8.20%,respectively.The result of high-throughput sequencing showed that WB and RB inhibited the relative abundance of methanogens by increasing fermentation temperature,while the addition of CB enriched the species of methanogens in the reactor. RDA result showed that the pore size of biochar was positively correlated with CH₄ release rate. In summary,adding WB and RB with a microporous structure has the best effect on CH₄ reduction in the aerobic fermentation process of municipal sludge under the conditions of this study.