Recycling of automobiles, home appliances and other metal-containing waste products produces large quantities of shredder waste which in most cases is landfilled. The waste contains CFCs due to the content of polyurethane insulation foam which may be released from the landfills. A study on a Danish landfill cell containing only shredder waste was carried out. The study combines laboratory and field investigations and includes shredder waste sampling and characterization, laboratory release and degradation experiments using the sampled shredder waste, and field investigations (landfill gas characterization and CFC fate and emission evaluation). The general gas composition within the shredder waste was 39% CH4 and 60% N2, containing no CO2 or only very low concentrations of CO2. Of the VOCs detected and quantified in the gas samples, HCFC-21 and HCFC-31 came out in relatively high concentrations (up to 32 μg L-1), indicating that anaerobic degradation of CFC-11 is occurring since neither of these compounds have been produced for industrial applications. The gas flux measurements together with an initial surface screening indicated that the gas emission from the shredder waste is low (below detection; < 0.1 g m-2 d-1) and limited to a few hot spots exhibiting high methane fluxes (6.0 – 97.1 g m-2 d-1). At one hot spot the emission of HCFC-21 and HCFC-31 was 0.005 and 0.006 g m-2 d-1, respectively. The shredder waste showed a relatively high capacity for methane oxidation, indicating that a significant part of the generated gas might be oxidized before emitted to the atmosphere. This was confirmed by shallow gas profiles showing methane oxidation and oxidation of HCFCs in the upper 40 cm of the shredder waste. The characterization of the PUR fraction contained in the shredder waste showed that the CFC-11 content of the PUR foam was much lower that predicted from a CFC release model, which indicates that compaction of the shredder waste may have enhanced the CFC release.
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机译：回收汽车，家用电器和其他含金属的废品会产生大量的切碎废料，在大多数情况下会被填埋。由于聚氨酯绝缘泡沫的含量，废物中可能含有CFC，这些泡沫可能会从垃圾填埋场释放出来。对仅包含切碎废料的丹麦垃圾掩埋场进行了研究。该研究将实验室和现场调查结合在一起，包括切碎废料的采样和表征，使用采样的切碎废料的实验室释放和降解实验以及实地调查（垃圾填埋气表征以及CFC的命运和排放评估）。切碎机废物中的一般气体成分为39％CH4和60％N2，其中不含CO2或仅含有非常低的CO2浓度。在气体样品中检测到并量化的挥发性有机化合物中，HCFC-21和HCFC-31的浓度相对较高（最高32μgL-1），这表明CFC-11发生了厌氧降解，因为这两种化合物都没有被生产用于工业应用。气体通量的测量以及初步的表面筛选表明，切碎机废料的气体排放量低（低于检测值; <0.1 g m-2 d-1），并且仅限于显示高甲烷通量的几个热点（6.0 – 97.1） g m-2 d-1）。在一个热点，HCFC-21和HCFC-31的排放分别为0.005和0.006 g m-2 d-1。切碎机废物显示出较高的甲烷氧化能力，这表明所产生的气体中有很大一部分在被排放到大气中之前可能会被氧化。浅层气体剖面证实了这一点，该剖面显示了粉碎机废料上部40 cm中的甲烷氧化和HCFC的氧化。对碎纸机废物中所含PUR馏分的表征表明，PUR泡沫中CFC-11的含量要比从CFC释放模型预测的要低得多，这表明碎纸机废物的压实可能增强了CFC的释放。
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