飞灰添加对沥青铺路烟气PAHs释放的影响

为评估生活垃圾焚烧飞灰替代矿粉生产沥青混合料及其路面浇筑全过程中PAHs的环境风险,采用实验室模拟与实际铺筑过程相结合的方法,改变飞灰添加量(以w计,0、3%、4%和5%)和加热温度(200、165、145和80 ℃),以对PAHs的释放规律进行研究. 结果表明:在实际筑路过程中,PAHs的释放受加热温度的影响较大,ρ(∑₁₆PAHs)随加热温度的下降而降低,其中混合料制备和道路开放使用阶段的ρ(∑₁₆PAHs)分别为249.0～378.0、72.1～95.1 μg/m3；但在路面浇筑阶段ρ(∑₁₆PAHs)有增加的趋势,为254.0～571.0 μg/m3,并且在该阶段内ρ(4环PAHs)降低,低环(2～3环)和高环(5～6环)的PAHs质量浓度升高. 飞灰的添加抑制了PAHs的释放,w(∑₁₆PAHs)在10.4～12.3 μg/kg之间,毒性当量浓度(以TEQ计)在0.011 μg/kg左右. 飞灰的添加抑制了以萘为主的低环PAHs的释放,并且在3%添加量时对PAHs的抑制效果最好；在飞灰添加量为3%、4%和5%时,w(萘)分别降低了42.7%、32.2%和35.3%. 

Simulation of PAHs Release in Municipal Solid Waste Incineration Fly Ash Application for Asphalt Pavement

Municipal solid waste incineration (MSWI) fly ash could substitute for mineral powder, which is a material used in asphalt pavement production. A laboratory test simulating the actual asphalt paving situation was conducted in which four kinds of fly ash adding proportions (0,3%, 4% and 5%) and five stages of heating temperature were set to study the PAHs release properties in the whole process of MSWI fly ash substituting for mineral powder in producing asphalt pavement. The results were as follows:ρ(∑₁₆PAHs) was influenced greatly by heat temperature, and ρ(∑₁₆PAHs) decreased as heat temperature declined. ρ(∑₁₆PAHs) in the preparation of the mixture stage and before the utilization stage were 249.0-378.0 mg/m3 and 72.1-95.1 μg/m3, respectively. However, there was a particular scenario in which ρ(∑₁₆PAHs) during the pavement and compression stage was higher than the other stages, being 254.0-571.0 μg/m3. What's more, ρ(4 rings-PAHs) were slumped and ρ(5-6 rings-PAHs) released reversely. The MSWI fly ash adding proportion in asphalt mixture also suppressed the release of PAHs. w(∑₁₆PAHs) varied with 10.4 μg/kg and 12.3 μg/kg, and the toxic equivalent (TEQ) of the PAHs released was 0.0110 TEQ μg/kg. Adding MSWI fly ash inhibited the release of PAHs. Besides, w(∑₁₆PAHs) was reduced most in the 3% control. Among all PAHs monomers, low molecular weight PAHs monomers were reduced most. For example, the naphthalene release amount (by mass) in adding proportion of fly ash 3%, 4% and 5% control was reduced 42.7%, 32.21% and 35.3%, respectively, compared with non-addition of fly ash,.