SUNYu-jia,XUZhi-qiang,GUANShuai,et al.Effect of Thermal and Alkali-Thermal Pretreatments on Methane Yield from High-iron-content Sludge[J].China Water & Wastewater,2025,41(9):116-122.
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Effect of Thermal and Alkali-Thermal Pretreatments on Methane Yield from High-iron-content Sludge

China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU] volume: 第41卷 Number: 第9期 Page: 116-122 Column: Date of publication: 2025-05-01
Author(s):
SUN　Yu-jia1; 2;  XU　Zhi-qiang1; 2;  GUAN　Shuai1; 3;  YU　Hui-yang1;  ZHANG　Zhuo1; 2;  LIU　Bo1; 2;  DONG　Wen1; 2;  WANG　Hui1; 2
（1. State Key Laboratory of Eco-Hydraulics in Northwest Arid Region of China， Xi’an University of Technology， Xi’an 710048， China； 2. College of Water Resources and Hydropower， Xi’an University of Technology， Xi’an 710048， China； 3. Xi’an TPRI Water-Management & Environment Protection Co. Ltd.， Xi’an 710054， China）
Keywords:
high-iron-content sludge;  alkali-thermal pretreatment;  methane production efficiency;  archaeal community
Abstract:
The addition of a substantial quantity of iron salts for chemical phosphorus removal and sludge conditioning in sewage treatment process can suppress the gas production efficiency during anaerobic sludge digestion. In this study, thermal and alkaline-thermal pretreatments of sludge were conducted to analyze the impacts of pretreatment methods on the gas production efficiency of anaerobic digestion of high-iron-content sludge. The cumulative methane production from high-iron-content sludge with iron content of (24.24±0.11) g/kg on a dry basis was 14.96% lower than that from biological sludge with iron content of (6.63±0.13) g/kg on a dry basis. After undergoing thermal and alkali-thermal pretreatments, the cumulative methane production of high-iron-content sludge increased by 40.25% and 72.70%, respectively. Furthermore, the maximum methane production potential (Um) and hydrolysis rate constant (khyd) exhibited the most significant enhancement following the alkali-thermal pretreatment. The yield of soluble carbohydrates (SC) released by alkali-thermal pretreatment was 1.61 times higher than that achieved by thermal pretreatment alone. Additionally, the growth rate of humic acid in sludge following alkali-thermal pretreatment was 5.86% greater compared to thermal pretreatment. In addition, the relative abundance of methanogenic archaea increased by 5.29%, and the activity of coenzyme F420 increased by 4.23% in the alkali-thermal pretreatment system. Therefore, alkali-thermal pretreatment is more advantageous for enhancing the gas production efficiency and ensuring the stability of sludge with high iron content.
Last Update: 2025-05-01