静态浸出测试评价飞灰及其处理产物的局限性

采用我国(GB)和美国(TCLP)静态浸出测试方法,评价生活垃圾焚烧飞灰及其稳定化产物的浸出毒性,并借助有效浸出测试、连续提取程序和动态(柱浸出)浸出测试方法,以两性重金属Pb为对象,探讨了静态浸出测试方法鉴别飞灰重金属浸出风险的局限性.结果表明:飞灰浸出液pH值对重金属浸出浓度有显著影响,使GB和TCLP评价结果不能有效预期飞灰稳定化产物随浸出环境而变化的长期浸出风险;由于静态浸出测试有较长的反应平衡时间,磷酸盐稳定化飞灰中的Pb在GB和TCLP测试中均达标,但在柱浸出测试初期却会因未达到足够的反应平衡而大量浸出,因而静态浸出测试会低估废物瞬时浸出风险.

Limitation of Static Leaching Test for Evaluating Leaching Toxicity of the Raw and Treated Air Pollution Control Residues

Standard static leaching tests of China(GB) and United States(TCLP) were used to identify the leaching toxicity of air pollution control(APC) residue from municipal solid waste incinerators,as well as its treatment products.Based on the availability leaching test,sequential extraction procedure and column leaching test,the limitation of the static leaching tests to identify the leaching risk of the ashes was discussed with regard to amphoteric lead.The results show that,heavy metals leaching concentrations are greatly dependent on the leachate pH of the ashes,as a result,GB and TCLP can not predict the long term leaching risk of the stabilized APC residues under variable environment.Due to the relatively long reaction time in the static leaching test,leached Pb is low and complied with the limit value of the GB and TCLP test,while considerable Pb is released from the leaching column in the initial stage.It indicates that the static leaching test can underestimate the quick leaching of Pb from the wastes before the system reaches(equilibrium.)