State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China.
Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto, 6158510, Japan.
Environ Pollut. 2022 Nov 1;312:120083. doi: 10.1016/j.envpol.2022.120083. Epub 2022 Sep 2.
This study focused on the syngenetic control of polychlorinated-ρ-dibenzodioxins and dibenzofurans (PCDD/Fs) and heavy metals by field stabilization/solidification (S/S) treatment for municipal solid waste incineration fly ash (MSWIFA) and multi-step leachate treatment. Modified European Community Bureau of Reference (BCR) speciation analysis and risk assessment code (RAC) revealed the medium environment risk of Cd and Mn, indicating the necessity of S/S treatment for MSWIFA. S/S treatment significantly declined the mass/toxic concentrations of PCDD/Fs (i.e., from 7.21 to 4.25 μg/kg; from 0.32 to 0.20 μg I-TEQ/kg) and heavy metals in MSWIFA due to chemical fixation and dilution effect. The S/S mechanism of sodium dimethyldithiocarbamate (SDD) and cement was decreasing heavy metals in the mild acid-soluble fraction to reduce their mobility and bioavailability. Oxidation treatment of leachate reduced the PCDD/F concentration from 49.10 to 28.71 pg/L (i.e., from 1.60 to 0.98 pg I-TEQ/L) by suspension absorption or NaClO oxidation decomposition, whereas a so-called "memory effect" phenomena in the subsequent procedures (adsorption, press filtration, flocculating settling, slurry separation, and carbon filtration) increased it back to 38.60 pg/L (1.66 pg I-TEQ/L). Moreover, the multi-step leachate treatment also effectively reduced the concentrations of heavy metals to 1-4 orders of magnitude lower than the national emission standards. Furthermore, the PCDD/Fs and heavy metals in other multiple media (soil, landfill leachate, groundwater, and river water) and their spatial distribution characteristics site were also investigated. No evidence showed any influence of the landfill on the surrounding liquid media. The slightly higher concentration of PCDD/Fs in the soil samples was ascribed to other waste management processes (transportation and unloading) or other local source (hazardous incineration plant). Therefore, proper management of landfills and leachate has a negligible effect on the surrounding environment.
本研究重点关注通过现场稳定/固化（S/S）处理对城市固体废物焚烧飞灰（MSWIFA）和多步浸出液处理进行多氯代-ρ-二苯并二恶英和二苯并呋喃（PCDD/Fs）和重金属的同生控制。经过改进的欧洲共同体基准局（BCR）形态分析和风险评估代码（RAC）揭示了 Cd 和 Mn 的中等环境风险，表明需要对 MSWIFA 进行 S/S 处理。S/S 处理显著降低了 MSWIFA 中 PCDD/Fs（即从 7.21 降至 4.25μg/kg；从 0.32 降至 0.20μg I-TEQ/kg）和重金属的质量/毒性浓度，这是由于化学固定和稀释效应。S/S 机制通过将二甲基二硫代氨基甲酸钠（SDD）和水泥中的重金属转化为可溶酸不溶部分来降低其移动性和生物利用度。浸出液的氧化处理通过悬浮吸收或 NaClO 氧化分解将 PCDD/F 浓度从 49.10 降至 28.71pg/L（即从 1.60 降至 0.98pg I-TEQ/L），而随后的程序（吸附、压滤、絮凝沉淀、泥浆分离和碳过滤）中出现了所谓的“记忆效应”现象，将其又增加至 38.60pg/L（1.66pg I-TEQ/L）。此外，多步浸出液处理还可有效将重金属浓度降低到比国家排放标准低 1-4 个数量级。此外，还研究了其他多种介质（土壤、垃圾填埋场浸出液、地下水和河水）中的 PCDD/Fs 和重金属及其空间分布特征现场。没有证据表明垃圾填埋场对周围液体介质有任何影响。土壤样品中 PCDD/Fs 浓度稍高归因于其他废物管理过程（运输和卸料）或其他本地源（危险焚烧厂）。因此，对垃圾填埋场和浸出液的适当管理对周围环境的影响可以忽略不计。
