我国南方某城市垃圾焚烧飞灰特性及固化/稳定化处置实验

我国南方某城市主要采用焚烧法处理生活垃圾,已建7个焚烧厂日产生飞灰量为101.62 t/d。文章分析了各个垃圾焚烧厂飞灰的化学组成和重金属浸出毒性,其主要成分为CaO、SiO2、MgO、Al2O3、Fe2O3、Na2O、SO3和Cl,所有焚烧飞灰都有至少一种重金属浸出浓度超标,属于危险废物。在飞灰处置出路亟待解决的背景下,实验探讨了飞灰稳定化工艺,结果表明10%的水泥添加量可以使飞灰中超标重金属(Cd、Pb和Zn)的浸出浓度满足危险废物鉴别浓度限值和安全填埋场入场浓度限值。同时,通过人体健康风险评价分析了飞灰豁免管理的可行性,并对近期和远期该城市焚烧厂飞灰的处理处置及管理提出建议。

Characteristics and Solidification/Stabilization Experiments of Fly Ashes from Municipal Solid Waste Incineration Plants in a Southern City

Municipal solid wastes in a southern city were disposed by incineration.Seven plants were constructed,which generate101.62 tons of fly ash per day.In this paper,the chemical compositions and leaching heavy metals of fly ashes from the incineration plants were analyzed.It showed that it mainly consisted of CaO,SiO2,MgO,Al2O3,Fe2O3,Na2O,SO3 and Cl.There was at least one of the heavy metals in the fly ashes from every plant over the discharge standard,belonging to hazardous wastes.Considering the urgent need for fly ash disposal,stabilization technology of fly ash was investigated.Addition of 10% cement into fly ashes can reduce the leaching concentrations of heavy metals（Cd,Pb,and Zn） under their regulatory limits for hazardous wastes identification and safe landfill.At the same time,feasibility of exemption of fly ash from hazardous wastes was analyzed on the basis of risk assessment of human health.Finally,the disposals of fly ash in this city at present and in the long term were discussed.