Maurice Christian, Lidelöw Sofia, Gustavsson Björn, Lättström Anders, Ragnvaldsson Daniel, Leffler Per, Lövgren Lars, Tesfalidet Solomon, Kumpiene Jurate
Ramböll, Luleå, Sweden.
Ambio. 2007 Sep;36(6):430-6. doi: 10.1579/0044-7447(2007)36[430:tftsaa]2.0.co;2.
Remediation mainly based on excavation and burial of the contaminated soil is impractical with regard to the large numbers of sites identified as being in need of remediation. Therefore, alternative methods are needed for brownfield remediation. This study was conducted to assess a chemical stabilization procedure of CCA-contaminated soil using iron (Fe)-containing blaster sand (BS) or oxygen-scarfing granulate (OSG). The stabilization technique was assessed with regard to the feasibility of mixing ameliorants at an industrial scale and the efficiency of the stabilization under different redox conditions. The stability was investigated under natural conditions in 1-m3 lysimeters in a field experiment, and the effect of redox conditions was assessed in a laboratory experiment (10 L). The treatments with high additions of ameliorant (8% and 17%) were more successful in both the laboratory and field experiments, even though there was enough Fe on a stochiometric basis even at the lowest addition rates (0.1% and 1%). The particle size of the Fe and the mixing influenced the stabilization efficiency. The development of anaerobic conditions, simulated by water saturation, increases the fraction of arsenic (AsIII) and, consequently, As mobility. The use of high concentrations of OSG under aerobic conditions increased the concentrations of nickel (Ni) and copper (Cu) in the pore water. However, under anaerobic conditions, it decreased the As leaching compared with the untreated soil, and Ni and Cu leaching was not critical. The final destination of the treated soil should govern the amendment choice, that is, an OSG concentration of approximately 10% may be suitable if the soil is to be landfilled under anaerobic conditions. Alternatively, the soil mixed with 1% BS could be kept under aerobic conditions in a landfill cover or in situ at a brownfield site. In addition, the treatment with BS appeared to produce better effects in the long term than treatment with OSG.
对于大量已确定需要修复的场地而言，主要基于挖掘和掩埋受污染土壤的修复方法并不实际。因此，需要采用替代方法来进行棕地修复。本研究旨在评估使用含铁喷砂砂（BS）或气刨颗粒（OSG）对经铬化砷酸铜（CCA）处理过的土壤进行化学稳定化处理的程序。该稳定化技术在工业规模下混合改良剂的可行性以及不同氧化还原条件下的稳定化效率方面进行了评估。在田间试验中，在1立方米的渗漏计中于自然条件下研究了稳定性，并在实验室试验（10升）中评估了氧化还原条件的影响。即使在最低添加率（0.1%和1%）下按化学计量计算有足够的铁，但在实验室和田间试验中，高添加量改良剂（8%和17%）的处理更为成功。铁的粒径和混合情况影响了稳定化效率。通过水饱和模拟的厌氧条件的发展增加了砷（AsIII）的比例，从而增加了砷的迁移性。在好氧条件下使用高浓度的OSG会增加孔隙水中镍（Ni）和铜（Cu）的浓度。然而，在厌氧条件下，与未处理的土壤相比，它降低了砷的浸出，并且镍和铜的浸出并不严重。处理后土壤的最终处置方式应决定改良剂的选择，也就是说，如果土壤要在厌氧条件下填埋，大约10%的OSG浓度可能是合适的。或者，与1% BS混合的土壤可以在好氧条件下保存在垃圾填埋场覆盖层中或在棕地现场原位保存。此外，从长期来看BS处理似乎比OSG处理产生更好的效果。
