预处理对河道底泥固化效果的影响

为了通过预处理改变底泥的理化性质,增加底泥固化后抗压强度,实现底泥的资源化利用,比较了3种底泥预处理方法(Fenton氧化、热处理、淋洗)对底泥中有机质的质量分数、重金属总质量、重金属形态分布,特别是对底泥固化后抗压强度的影响。结果表明:固化后抗压强度与底泥中有机质的质量分数直接相关;可降低底泥中有机质的质量分数的预处理方法(Fenton氧化、热处理)对提高底泥固化后抗压强度效果较好,底泥固化后抗压强度高达2.7 MPa;鼠李糖脂淋洗虽然能够有效去除底泥中的重金属,但是淋洗剂中的有机物反而使底泥中有机质的质量分数增加,对固化不利。因此,Fenton氧化和热处理均可用作提高底泥固化强度的预处理方法,且固化后试样重金属浸出毒性低,对环境影响小。

Effects of the pretreatments on the river sediment solidification

Due to its physical and chemical property changes through pre-treatments, effects of pre-treatments including Fenton oxidation, heat treatment and washing on organic content, heavy metal content, heavy metal speciation and compressive strength after solidification were compared in this paper with the purpose of increasing the compressive strength of solidified sediment, which could realize the sediment reuse. The results showed that compressive strength of the solidified sediment was closely related to its organic content. Pretreatments, such as Fenton oxidation and heat treatment, which could reduce the organic content had the best effect on improving compressive strength. The highest compressive strength of 2.7 MPa could be reached. By comparison, rhamnolipid washing had effect on heavy metal removal. However, it resulted in the rising of organic content and thus had adverse effect on the solidification. Therefore, Fenton oxidation and heat treatment were recommended as the pretreatment to further increase the compressive strength. In addition, the solidified samples with low heavy metal leaching had less impact on the environment.