National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing, 100124, PR China.
National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing, 100124, PR China.
J Hazard Mater. 2019 May 5;369:164-170. doi: 10.1016/j.jhazmat.2019.02.023. Epub 2019 Feb 10.
Extracellular nitrite has been used to improve the digestion of waste activated sludge (WAS). However, the underlying mechanism remains largely unknown. In this study, WAS was treated with 0.2 gNO-N/gVSS for 7 days and its performance was compared to that of aerobic and anaerobic treatments. The addition of nitrite had a distinct effect on the reduction of VSS/SS and the accumulation of soluble organics compared to the control reactors. As evident by the variations of extracellular polymeric substances (EPS), nitrite addition had a positive effect on decreasing protein. In particular, the decrease of protein mainly occurred in tightly bound EPS (TB-EPS), which caused sludge disintegration and enhanced sludge reduction. Additionally, the decrease of microbial diversity with nitrite addition was significant compared to the control reactors, accompany with a decrease of live/dead cells ratio and an increase of supernatant DNA concentration. This suggests that nitrite could cause cell death and lysis, resulting in sludge degradation. Thus, nitrite addition enhanced sludge treatment through the combined effect of TB-EPS disintegration and cell lysis. These findings will be useful for the optimization of sludge treatment process based on nitrite addition.
亚硝酸盐已被用于改善废活性污泥（WAS）的消化。然而，其潜在机制在很大程度上尚不清楚。在本研究中，用 0.2gNO-N/gVSS 处理 WAS 7 天，并将其性能与好氧和厌氧处理进行比较。与对照反应器相比，亚硝酸盐的添加对 VSS/SS 的减少和可溶性有机物的积累有明显的影响。通过对胞外聚合物物质（EPS）的变化可以明显看出，添加亚硝酸盐对减少蛋白质有积极作用。特别是，蛋白质的减少主要发生在紧密结合的 EPS（TB-EPS）中，这导致污泥解体并增强了污泥的减少。此外，与对照反应器相比，添加亚硝酸盐后微生物多样性的减少是显著的，伴随着活/死细胞比例的降低和上清液 DNA 浓度的增加。这表明亚硝酸盐会导致细胞死亡和裂解，从而导致污泥降解。因此，通过 TB-EPS 解体和细胞裂解的综合作用，添加亚硝酸盐增强了污泥处理。这些发现将有助于优化基于添加亚硝酸盐的污泥处理工艺。
