摘要
研究了硫酸铝、氯化钙、β-奈系减水剂这几种固化剂对固化处理后的城市污水处理厂污泥(简称城市污泥)固化块抗压强度和重金属浸出特性的影响。结果表明,硫酸铝、氯化钙、β-奈系减水剂的最佳掺量分别为30、10、8 g/kg(以城市污泥计),制得的城市污泥固化块养护7 d后的抗压强度可达1.6 MPa,3种固化剂的最佳配合使用能较大地提高固化块的抗压性能,固化处理后的城市污泥能充分满足填埋的土力学强度要求;固化块浸出液中的重金属含量较城市污泥浸出液进一步降低,固化剂可以对城市污泥中的重金属起到良好的固定作用;通过X射线衍射(XRD)仪和扫描电镜(SEM)分析发现,固化块结构密实,存在原硅酸钙、碳酸钙、水化硅酸钙等物质,这有利于固化块抗压强度的提高,并能有效地阻碍重金属离子的溶出。
The sewage sludge was solidification treated by 3 solidifying agent of aluminum sulfate,calcium chloride and β-naphthalene superplasticizer,the effect of solidifying agent dosage on compressive strength and heavy metal leaching character of solidification blocks was investigated.Results indicated that the best quantity of aluminum sulfate,calcium chloride and β-naphthalene superplasticizer was 30,10,8 g/kg respectively,the compressive strength of obtained solidification blocks could reach to 1.6 MPa after curing for 7 d.Applying the mixture of 3 solidifying agent could improve the blocks compressive strength obviously,so that it can fully meet the mechanical strength requirements in landfill soil.Solidifying agent presented perfect performance on heavy metal fixation,for the concentration of heavy metal in leaching solution of solidification blocks was higher than that in sewage sludge.The XRD and SEM analysis showed that the structure of sludge solidified blocks was dense with the existence of Ca2SiO4,CaCO3 and other materials,which were beneficial to improve the compressive strength of the solidification blocks and hinder the leaching of heavy metals.
出处
《环境污染与防治》
CAS
CSCD
北大核心
2011年第2期74-78,共5页
Environmental Pollution & Control
基金
上海市科学技术委员会资助项目(No.9DZ1200108)
关键词
固化剂
城市污水处理厂污泥
固化
重金属
抗压强度
solidifying agent
sewage sludge
solidification
heavy metal
compressive strength
