生化降解条件下水泥固化污泥的微观结构研究

Research on Microstructure of Solidified Sludge Using Cement Under Biochemical Degradation

采用水泥作为基材对污泥进行固化处理是污泥常用的预处理技术之一,但是污泥中有机质的降解会影响到固化体的微观结构,进而影响到宏观力学性质以及对污染物的封闭效应.通过好氧、厌氧以及添加渗滤液条件下的生化降解试验,获得了固化污泥有机质的降解规律;利用扫描电镜(SEM)与GIS技术对不同降解条件和不同降解时间下固化污泥的SEM图像进行微观结构的定性和定量研究,获得了固化污泥微观结构的变化规律.结果表明,三维sEM图像能够反映降解过程中固化污泥内部微观结构的变化;固化污泥的三维孔隙率变化分为3个阶段:加速降解阶段、过渡阶段以及降解稳定阶段,固化污泥的微观结构变化受到有机质降解过程的控制,三维孔隙率与有机质含量呈负相关关系.

Solidification using cement is a commonly treatment technology for sludge pretreatment. Under the biochemistry conditions of landfill,the organics would be degraded,which affect the mechanical properties of solidified sludge.The changes of microstructure characteristics with degradation were the determinants of mechanical properties.The bioremediation experiments of solidified sludge were designed under aerobic conditions,anaerobic conditions and adding the leachate,which were performed to get the law of organic matter degradation.The changes of solidified sludge microstructure were analyzed based on the scanning electron microscope (SEM)and GIS technology under different conditions.The resuhs showed that 3D SEM images could reflect the changing process of microstructure morphology during the degradation.The changes of 3D porosity of solidified sludge could be divided into three stages: accelerate stage, transition stage and stable stage,which was roughly identical to the rule of organic matter degradation.These considerations suggest that the change of solidified sludge microstructure was determined by the organic matter degradation,and the 3D porosity of solidified sludge was negatively related with the organic content.