【作者】 郑军；

【导师】 陈洪波；

【作者基本信息】 湘潭大学 ， 环境工程， 2025， 硕士

【摘要】 厌氧消化在实现污泥减量以及资源回收方面具有显著优势,但污泥细胞及胞外聚合物的传质屏障效应严重制约着有机物的溶出效率,导致污泥厌氧消化速率及有机物转化率受到限制。热水解预处理可有效破坏污泥的絮体结构,提高有机物的溶出与水解速率,但其高温条件会加剧类黑素等难降解物质的生成,从而对后续厌氧消化过程产生不利影响。针对这一问题,本研究提出将热水解与高铁酸钾进行耦合,以进一步提高污泥厌氧消化性能。首先,评估了联合预处理强化污泥产甲烷性能,并通过研究污泥结构、有机物可生物降解性以及微生物代谢活性的变化来揭示其潜在机理。随后,评估了联合预处理强化高含固污泥产酸性能。根据发酵期间的溶解性有机物、污泥电化学特性以及产酸相关酶活性的变化来探究其强化机制,并通过相关性分析阐明预处理参数与短链脂肪酸生物转化过程的关联机制。得到的主要研究结果如下:(1)在增强污泥产甲烷方面,联合预处理组的累计甲烷产量达到215 m L/g VS,较对照组提升82.2%。热水解预处理破坏了污泥胞外聚合物的半刚性结构,使得高铁酸钾更容易接触细胞并造成损伤。联合预处理通过对胞外聚合物和细胞的双重破坏导致污泥中的有机物大量溶解。此外,高铁酸钾进一步提高了污泥的可生物降解性。高铁酸钾产生的三价铁会诱导异化铁还原过程并增强微生物电子传递活性,进而增加了与水解和酸化过程相关微生物的丰度,但抑制了氢营养型产甲烷菌的生长。(2)在增强高含固污泥产酸方面,联合预处理有效解决了厌氧发酵中160℃的热水解预处理所产生的类黑素抑制产酸的难题。在160℃、30分钟的热水解预处理和0.05 g/g TSS的高铁酸钾预处理的协同作用下,溶解性化学需氧量最高提升至12,516 mg/L,且高铁酸钾通过选择性降解类黑素来缓解其抑菌效应,促使短链脂肪酸产量进一步增至5377 mg COD/L。联合预处理产生的氧化还原介质和腐殖质提高了体系电导率和电子传递活性,加速了细胞外电子传递,并使酸化酶活性提升。相关性分析证实160℃的热水解预处理所产生的类黑素对酸生成具有抑制作用,而高铁酸钾有效破坏了其共轭结构,并裂解了大分子有机物的醚键和肽键,进一步提高底物可生物利用性。本文阐明了热水解联合高铁酸钾预处理增强污泥厌氧消化性能的可行性及其潜在作用机制,为现有污泥热水解厌氧消化工艺的优化提供了创新思路,对推动市政污泥的能源化最大化回收与可持续处理具有重要参考价值。更多还原

【Abstract】 Anaerobic digestion has significant advantages in achieving sludge reduction and resource recovery,but the mass transfer barrier effect of sludge cells and extracellular polymers severely restricts the dissolution efficiency of organic matter,resulting in the limitation of sludge anaerobic digestion rate and organic matter conversion rate.Thermal hydrolysis pretreatment can effectively destroy the floc structure of sludge and improve the dissolution and hydrolysis rate of organic matter,but its high temperature conditions will exacerbate the generation of difficult-to-degrade substances such as melanoidins,which will harm the subsequent anaerobic digestion process.To address this issue,this study proposed coupling thermal hydrolysis with potassium ferrate to improve the anaerobic digestion performance of sludge further.Firstly,the enhanced sludge methanogenic performance of the combined pretreatment was evaluated,and the potential mechanism was revealed by investigating the changes in sludge structure,organic matter biodegradability,and microbial metabolic activity.Subsequently,the acid-producing performance of combined pretreatment-enhanced high-solids sludge was evaluated.The enhancement mechanism was investigated based on changes in dissolved organic matter,sludge electrochemical properties,and acid-producing enzyme activities related to fermentation.A correlation analysis was conducted to elucidate the association mechanism between pretreatment parameters and the bioconversion process of short-chain fatty acids.The main findings were as follows:(1)In terms of enhancing sludge methane production,the cumulative methane production of the combined pretreatment group reached 215 m L/g VS,which was82.2%higher than that of the control group.Thermal hydrolysis pretreatment disrupted the semi-rigid structure of sludge extracellular polymers,making it easier for potassium ferrate to contact the cells and cause damage.The combined pretreatment led to a significant dissolution of organic matter in the sludge through the dual damage to the extracellular polymer and cells.In addition,the biodegradability of the sludge was further enhanced by potassium ferrate.Trivalent iron produced by potassium ferrate induces heterogeneous iron reduction processes and enhances microbial electron transfer activity,which in turn increases the abundance of microorganisms associated with hydrolysis and acidification processes,but inhibits the growth of hydrogenotrophic methanogenic bacteria.(2)In the enhancement of acid production from high-solids sludge,the combined pretreatment effectively solved the problem of acid production inhibition by melanoidins produced by the thermal hydrolysis pretreatment at 160℃in anaerobic fermentation.Under the synergistic effect of the thermal hydrolysis pretreatment at160℃for 30 min and the potassium ferrate pretreatment at 0.05 g/g TSS,the dissolved COD was increased up to 12,516 mg/L,and the inhibitory effect of potassium ferrate was mitigated by the selective degradation of melanoidins,which led to a further increase in the production of short-chain fatty acids to 5,377 mg COD/L.Redox mediators and humic substances generated from the combined pretreatment enhanced the acid production of high solids sludge,which was a major challenge in the anaerobic fermentation.medium and humus increased the system conductivity and electron transfer activity,accelerated the extracellular electron transfer,and enhanced the acidifying enzyme activity.The correlation analysis confirmed that the melanoidins produced by the thermal hydrolysis pretreatment at 160℃inhibited the acid generation,while potassium ferrate effectively destroyed the conjugated structure and cleaved the ether and peptide bonds of the macromolecules,which further improved the bioavailability of the substrate.This paper elucidates the feasibility of thermal hydrolysis combined with potassium ferrate pretreatment to enhance the anaerobic digestion performance of sludge and its potential mechanism of action,which provides innovative ideas for the optimization of the existing sludge thermal hydrolysis anaerobic digestion process,and has an important reference value for promoting the energy maximization of municipal sludge recovery and sustainable treatment.更多还原