满足《生活垃圾填埋污染控制标准》的生活垃圾焚烧飞灰重金属药剂稳定化研究

Chemical stabilization of fly ash for satisfying landfill criteria of municipal solid waste landfill site

基于《生活垃圾填埋污染控制标准》(GB 16889—2008)对生活垃圾焚烧飞灰(以下简称飞灰)的豁免管理规定,选用磷酸盐组合药剂和硫基螯合剂对飞灰进行重金属稳定化实验,考察了2类药剂对飞灰重金属的稳定效果,寻求达到最佳重金属稳定效果的药剂添加量,同时分析了稳定化飞灰进入生活垃圾填埋场时初期渗滤液中的重金属浸出情况。结果表明,磷酸盐组合药剂的最佳添加量为8%(质量分数),稳定化飞灰的含水率为18%左右,稳定化飞灰浸出液中的相应重金属含量均符合GB 16889—2008的限值要求;硫基螯合剂的最佳添加量为21%(质量分数,下同),稳定化飞灰浸出液中的重金属含量均低于GB 16889—2008的限值,但是当硫基螯合剂添加量过高(36%)时,稳定化飞灰浸出液中的Pb会超标;2类药剂稳定化飞灰进入生活垃圾填埋场对初期渗滤液中的各重金属浸出浓度基本都呈现出初期快速降低,之后缓慢降低并趋于平衡的变化趋势,稳定化飞灰进入生活垃圾填埋场时仍需要注意初期渗滤液中部分重金属超标的潜在可能性。

Base on the exemption management of Standard for Pollution Control on the Landfill Site（GB 16889—2008） to fly ash,the phosphate combing agent and sulphurate chelating agent were chosen to stabilize MSWI（municipal solid waste incineration） fly ash.The stabilization performance of two agents was investigated by analyzing the leaching concentration of heavy metal from fly ash,and the best adding dosage of two agents was found out.The experimental results showed when 8% of phosphate combing agent or 21% sulphurate chelating agent added to fly ash,the leaching concentration of heavy metal in products could satisfy the standard of GB 16889—2008.Higher sulphurate chelating agent（36%） could increase the leaching concentration of Pb to 1.131 mg/L,which exceed the landfill standard.Leaching concentration of heavy metal decreased quickly at the beginning of the leaching process,and then they stayed in a relative stable value.The experimental results indicated that when stabilized fly ash entered MSW landfill,the risk of heavy metal in leachate at initial stage should be paid attention.