Hydrothermal pretreatment (HTP) of sewage sludge (SS) has been shown to improve the subsequent biogas production by anaerobic digestion (AD), but the effect of catalysts on HTP performance was less explored. This study intended to investigate the SS pretreatment by wet air oxidation (WAO) with the addition of K₂CO₃ as a catalyst on the performance of methane production by AD. WAO was found to improve the solubilization of SS, the soluble chemical oxygen demand, dissolved organic carbon, and total dissolved nitrogen. The methane yield from WAO increased from 202 mL/gVS_in with no catalyst added to 277 mL/gVS_in with 10 wt% of K₂CO₃ added at 180 °C with 30 min of residence time. Under this pretreatment condition, the highest methane production rate could achieve 15.8 mL/gVS_in day, and the percentage of methane reached 73%. The structure of the microbial community involved in the AD was affected by the residence time, working gas, and catalyst of the HTP process. The results showed that Bacteroidetes, Bacteroidia, and SC103 were the dominant phylum, class, and genus of bacteria, respectively, of almost all of the samples. In addition, the most abundant archaeal order was Methanosarcinales, while Methanosaeta was the dominant archaeal genus of most of the samples. However, Methanosarcina largely increased the relative abundance, corresponding to the amount of K₂CO₃ catalyst used. The findings in this study demonstrated the potential use of K₂CO₃ during WAO of SS and implied the link between shift of methanogen community and the enhanced methane yield in AD.

污水污泥（SS）的水热预处理（HTP）已显示可通过厌氧消化（AD）改善随后的沼气生产，但很少探讨催化剂对HTP性能的影响。这项研究旨在研究通过湿空气氧化（WAO），加入K ₂ CO ₃作为催化剂对SS预处理对AD生产甲烷的性能的影响。发现WAO可改善SS的溶解性，可溶化学需氧量，可溶有机碳和总可溶氮。从WAO甲烷产量从202毫升/ GVS增加_在没有添加到277毫升/ GVS催化剂_在具有K的10％（重量）₂ CO ₃在180°C下加入30分钟的停留时间。在此处理条件，最高甲烷产率可以达到15.8毫升/ GVS_在 白天和甲烷的比例达到73％。AD中涉及的微生物群落结构受停留时间，工作气体和HTP过程催化剂的影响。结果表明，几乎所有样品中的拟杆菌，细菌和SC103分别是细菌的显性门，类别和属。此外，最丰富的古细菌属是甲烷菌，而甲烷菌是大多数样品的主要古细菌属。然而，甲烷八叠球菌大大增加了相对丰度，对应于钾的量_使用2 CO ₃催化剂。这项研究的结果表明，SS的WAO期间可能使用K ₂ CO ₃，这暗示了甲烷源菌群落的变化与AD中甲烷产量的增加之间存在联系。