Pantini Sara, Verginelli Iason, Lombardi Francesco
Department of Civil Engineering and Computer Science Engineering, University of Rome "Tor Vergata", Via del Politecnico, 1, 00133 Rome, Italy.
Department of Civil Engineering and Computer Science Engineering, University of Rome "Tor Vergata", Via del Politecnico, 1, 00133 Rome, Italy.
Waste Manag. 2015 Apr;38:22-32. doi: 10.1016/j.wasman.2014.12.002. Epub 2015 Jan 8.
The leaching behavior of wastes coming out from Mechanical Biological Treatment (MBT) plants is still poorly investigated in literature. This work presents an attempt to provide a deeper insight about the contaminants release from this type of waste. To this end, results of several batch and up-flow percolation tests, carried out on different biologically treated waste samples collected from an Italian MBT plant, are reported. The obtained results showed that, despite MBT wastes are characterized by relatively high heavy metals content, only a limited amount was actually soluble and thus bioavailable. Namely, the release percentage was generally lower than 5% of the total content with the only exception of dissolved organic carbon (DOC), Zn, Ni and Co with release percentages up to 20%. The information provided by the different tests also allowed to highlight some key factors governing the kinetics release of DOC and metals from this type of material. In particular, results of up-flow column percolation tests showed that metals such as Cr, Mg, Ni and Zn followed essentially the leaching trend of DOC suggesting that these elements were mainly released as organo-compounds. Actually, a strong linear correlation (R(2) > 0.8) between DOC and metals concentration in eluates was observed, especially for Cr, Ni and Zn (R(2)>0.94). Thus, combining the results of batch and up-flow column percolation tests, partition coefficients between DOC and metals concentration were derived. These data, coupled with a simplified screening model for DOC release, allowed to get a very good prediction of metal release during the different column tests. Finally, combining the experimental data with a simplified model provided some useful indications for the evaluation of long-term emissions from this type of waste in landfill disposal scenarios.
机械生物处理（MBT）工厂产生的废弃物的浸出行为在文献中仍未得到充分研究。这项工作试图更深入地了解这类废弃物中污染物的释放情况。为此，报告了对从意大利一家MBT工厂收集的不同生物处理废弃物样本进行的多次批次和上流渗滤试验的结果。所得结果表明，尽管MBT废弃物的重金属含量相对较高，但实际可溶且具有生物可利用性的量有限。也就是说，释放百分比通常低于总含量的5%，只有溶解有机碳（DOC）、锌、镍和钴除外，其释放百分比高达20%。不同试验提供的信息还突出了控制这类物质中DOC和金属动力学释放的一些关键因素。特别是，上流柱渗滤试验结果表明，铬、镁、镍和锌等金属基本上遵循DOC的浸出趋势，这表明这些元素主要以有机化合物的形式释放。实际上，在洗脱液中观察到DOC与金属浓度之间存在很强的线性相关性（R²>0.8），尤其是铬、镍和锌（R²>0.94）。因此，结合批次和上流柱渗滤试验的结果，得出了DOC与金属浓度之间的分配系数。这些数据，再加上一个简化的DOC释放筛选模型，能够很好地预测不同柱试验期间的金属释放。最后，将实验数据与一个简化模型相结合，为评估这类废弃物在填埋处置场景中的长期排放提供了一些有用的指示。
