College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China.
College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China.
Sci Total Environ. 2023 Jul 1;880:163025. doi: 10.1016/j.scitotenv.2023.163025. Epub 2023 Mar 24.
The presence of surfactants in waste activated sludge (WAS) system is generally regarded as beneficial to sludge treatment such as enhancing sludge dewatering and improving value-added fermentation products generation. However, in this study, it was firstly found that sodium dodecylbenzene sulfonate (SDBS, a typical surfactant) obviously increased toxic hydrogen sulfide (HS) gas production from WAS anaerobic fermentation at environmentally relevant concentrations. Experimental results showed that HS production from WAS significantly increased from 53.24 × 10 to 111.25 × 10 mg/g volatile suspended solids (VSS) when SDBS level increased from 0 to 30 mg/g total suspended solid (TSS). It was found that SDBS presence destroyed WAS structure and enhanced sulfur containing organics release. SDBS reduced the proportion of α-helix structure, damaged disulfide bridges and protein conformation, and effectively destroyed protein structure. SDBS promoted sulfur containing organics degradation and provided more readily hydrolyzed micro-molecule organics for sulfide production. Microbial analysis showed that SDBS addition enhanced the abundance of functional genes encoding protease, ATP-binding cassette transporters, and amino acids lyase, enhanced the activities and abundance of hydrolytic microbes, thus increased sulfide production from the hydrolysis of sulfur containing organics. Compared with the control, 30 mg/g TSS SDBS increased organic sulfurs hydrolysis and amino acids degradation by 47.1 % and 63.5 %, respectively. Key genes analysis further showed that SDBS addition promoted sulfate transport system and dissimilatory sulfate reduction. SDBS presence also lowered fermentation pH, promoted the chemical equilibrium transformation of sulfide, thus increased HS gas release.
表面活性剂在废活性污泥（WAS）系统中的存在通常被认为有利于污泥处理，例如增强污泥脱水和提高增值发酵产品的生成。然而，在本研究中，首次发现十二烷基苯磺酸钠（SDBS，一种典型的表面活性剂）在环境相关浓度下明显增加了 WAS 厌氧发酵产生的有毒硫化氢（HS）气体。实验结果表明，当 SDBS 水平从 0 增加到 30mg/g 总悬浮固体（TSS）时，HS 从 WAS 中的产生量从 53.24×10 增加到 111.25×10mg/g 挥发性悬浮固体（VSS）。发现 SDBS 的存在破坏了 WAS 的结构并增强了含硫有机物的释放。SDBS 降低了α-螺旋结构的比例，破坏了二硫键和蛋白质构象，并有效地破坏了蛋白质结构。SDBS 促进了含硫有机物的降解，并为硫化物的产生提供了更多易于水解的小分子有机物。微生物分析表明，SDBS 的添加增强了编码蛋白酶、ATP 结合盒转运蛋白和氨基酸裂解酶的功能基因的丰度，增强了水解微生物的活性和丰度，从而增加了含硫有机物水解产生的硫化物。与对照组相比，30mg/g TSS 的 SDBS 分别增加了有机硫和氨基酸的水解 47.1%和 63.5%。关键基因分析进一步表明，SDBS 的添加促进了硫酸盐转运系统和异化硫酸盐还原。SDBS 的存在还降低了发酵 pH 值，促进了硫化物的化学平衡转化，从而增加了 HS 气体的释放。
