State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
Tongji Architectural Design (Group) Co., Ltd., Shanghai, 200092, China.
Chemosphere. 2020 Mar;243:125421. doi: 10.1016/j.chemosphere.2019.125421. Epub 2019 Nov 22.
A sludge structure perspective of the effects of humic matter (HM) on the anaerobic digestion (AD) of sewage sludge was proposed and investigated in this study. It was observed that the net cumulative methane production of sludge was significantly lower in the presence of HM. The fractal dimension values of sludge samples were increased by the addition of HM, whilst their total surface energy values were decreased, indicating that HM reinforced the stability of the sludge structure. Analyses of the physicochemical properties of different sludge samples revealed that HM enhanced the structural stability of sludge organic substances and restricted its organic solubility by interacting with the biopolymers to form a dense granular aggregate, thereby reducing the random-coil degree of extracellular organic substances and its active sites for enzymes, which suggested that HM could inhibit AD by changing the sludge structure. It was further confirmed by the biochemical methane potential (BMP) assay process. The BMP tests and corresponding kinetic analyses revealed that HM can restrict the potentials of sludge organic solubilisation, hydrolysis and acidification processes, but not necessarily the rates of these processes by enhancing the structural stability of high molecular weight readily biodegradable organic matter (RBOM) and restricting the mobility of low molecular weight RBOM (i.e., hydrolysis products). These findings can enrich understanding of the AD of sludge and may thus aid in the development of more effective methods to improve sludge treatment.
本研究提出并探讨了腐殖质（HM）对污水污泥厌氧消化（AD）影响的污泥结构观点。结果表明，HM 的存在显著降低了污泥的净累积甲烷产量。添加 HM 后，污泥样品的分形维数值增加，而总表面能值降低，表明 HM 增强了污泥结构的稳定性。对不同污泥样品理化性质的分析表明，HM 通过与生物聚合物相互作用形成致密的颗粒状聚集体，增强了污泥有机物质的结构稳定性，限制了其有机溶解度，从而降低了细胞外有机物质的无规卷曲程度及其对酶的活性位点，这表明 HM 可以通过改变污泥结构来抑制 AD。这通过生化甲烷潜力（BMP）测定过程进一步得到证实。BMP 测试和相应的动力学分析表明，HM 可以通过增强高分子量易生物降解有机物（RBOM）的结构稳定性并限制低分子量 RBOM（即水解产物）的迁移性来限制污泥有机溶解、水解和酸化过程的潜力，但不一定限制这些过程的速率。这些发现可以丰富对污泥 AD 的理解，从而有助于开发更有效的方法来改善污泥处理。
