垃圾焚烧飞灰或炉渣中二噁的分布特征

分别采集了3种生活垃圾焚烧炉产生的飞灰或熔融炉渣样品,分析了其中的二口恶口英含量及其毒性当量,并讨论了17种2,3,7,8位氯取代的二口恶口英分布特征及其对总毒性当量的贡献.结果表明,机械炉排焚烧炉产生的飞灰中二口恶口英最多,总浓度为319ng/g,毒性当量为6.7ngI-TEQ/g;其次为流化床焚烧炉,产生的飞灰中二口恶口英总浓度为38.7ng/g,毒性当量为0.8ngI-TEQ/g;气化熔融焚烧炉产生的熔融炉渣中二口恶口英很少,总浓度为38.7pg/g,毒性当量仅为1.1pgI-TEQ/g;所有的2,3,7,8位氯取代的13C同位素标记内标化合物回收率在39%~156%之间.尽管不同的垃圾焚烧炉在二口恶口英的生成量上有明显的差别,但是产生的二口恶口英同类物的归一化浓度以及对毒性当量贡献的归一化结果分布特征十分相似,表明3种垃圾焚烧炉在垃圾焚烧过程产生二口恶口英可能具有相似的反应机理.

Distribution characters of polychlorinated dibenzo-p-dioxins and dibenzofurans in fly ash or slag from municipal waste incineration.

The fly ash or slag samples produced from three kinds of municipal waste incinerators were collected respectively. In these samples the content and toxicity equivalent of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed, and the distribution character and its contribution to the total toxicity equivalent of 17 species 2,3,7,8-chlorinated substitutive PCDD/Fs were discussed. The PCDD/Fs in fly ash produced from stoker incinerator was the most, with total concentration of 319ng/g and TEQ of 6.7ng I-TEQ/g. Next the fly ash from fluidized bed incinerator, the total concentration of PCDD/Fs was 38.7ng/g, and of TEQ was 0.8ng I-TEQ/g. Only a little of PCDD/Fs was found in the slag produced by gasified and melting incinerator, with total concentration of 38.7pg/g, and that of TEQ only 1.1pg I-TEQ/g. The recovery ratios of 2,3,7,8 chlorinated substituted 13C labelled isotope compounds were 39%~156%. In spite of the distinct difference in the produce of PCDD/Fs from municipal waste incinerator, the distribution characters of normalized concentrations and contributions to TEQ of PCDD/Fs homologue were so similar that the PCDD/Fs produced in the processes of combustion of these three kinds of incinerators might possess similar reaction mechanism.