Abstract:
Carbon recovery from waste activated sludge has been attracting considerable attention. However, the migration and transformation patterns of carbon sources between the phases have rarely been reported. In this study, a novel strategy using cation exchange resin (CER) coupled with sodium chloride (NaCl) to enhance carbon recovery through anaerobic fermentation (AF) was proposed. The results demonstrated that CER coupled with NaCl destroyed OH and CO stretching in amide I while promoting the formation of β-sheet and random coil structures, leading to sludge disintegration. This significantly improved the kinetics of endogenous carbon release, resulting in the release of 1146.33 mg/L of carbon from the solid sludge into the liquid phase. Approximately 75.61 % of the initial carbon source was bio-transformed into short-chain fatty acids. Correspondingly, carbon recovery was significantly increased up to 852.23 mg C/L, 4.57 times that of the control. Mechanism exploration revealed that carbon source recovery was significantly elevated by the synergistic effect of CER and NaCl. CER effectively removed high-valence cations from extracellular polymeric substance (EPS), weakening its bridging and adsorption-electro neutralization capabilities, promoting protein deflocculation, and triggering EPS disruption to release extracellular carbon sources. NaCl disrupted the ionic strength and distribution inside and outside microbial cells, creating an osmotic pressure difference that resulted in cell plasmolysis and lysis, ultimately inducing the release of intracellular carbon sources. Economic and carbon emission reduction benefit analyses verified that the CER coupled with NaCl pretreatment is a cost-effective sludge treatment strategy. This study illustrates the carbon source migration and transformation pathways in the CER coupled with NaCl-assisted AF process, providing guidance for sustainable sludge management.
摘要:
从废活性污泥中回收碳已经引起了相当多的关注。然而,碳源在相之间的迁移和转化模式很少有报道。在这项研究中,提出了一种使用阳离子交换树脂(CER)和氯化钠(NaCl)通过厌氧发酵(AF)提高碳回收率的新策略。结果表明,CER与NaCl偶联破坏了酰胺I中的OH和CO拉伸,同时促进了β-折叠和无规卷曲结构的形成,导致污泥崩解。这显著改善了内源性碳释放的动力学,导致1146.33mg/L的碳从固体污泥释放到液相中。大约75.61%的初始碳源被生物转化为短链脂肪酸。相应地,碳回收率显著提高至852.23mgC/L,是对照组的4.57倍。机理探索表明,CER和NaCl的协同作用显著提高了碳源回收率。CER有效地从细胞外聚合物(EPS)中去除高价阳离子,削弱其桥接和吸附电中和能力,促进蛋白质反絮凝,并触发EPS破坏以释放细胞外碳源。NaCl破坏了微生物细胞内外的离子强度和分布,产生渗透压差,导致细胞质解和裂解,最终诱导细胞内碳源的释放。经济和碳减排效益分析验证了CER与NaCl预处理相结合是一种经济有效的污泥处理策略。这项研究说明了CER与NaCl辅助AF过程耦合的碳源迁移和转化途径。为可持续污泥管理提供指导。