重金属污染底泥土工管袋脱水与烧制陶粒应用

Dewatering of heavy metal contaminated sediments with geotextile tube for the preparation of ceramsite

针对某项目重金属污染底泥,筛选优化了5种重金属稳定剂、7种絮凝剂及其用量,开展了土工管袋脱水小试实验,并将脱水后重度污染底泥烧制成陶粒。结果显示:采用重金属稳定剂W-2,在投加量为底泥干重5%时,As、Pb、Hg、Ni和Cu的稳定化率分别为55.8%、86.9%、70.9%、79.0%和75.9%;采用絮凝剂M603,在投加量为底泥干重0.3%时,底泥含水率从95%降至68.4%,上清液COD值为32.5 mg/L,达到GB 3838—2002《地表水环境质量标准》中V类标准;土工管袋脱水效果显著,余水中固体悬浮物浓度低至11 mg/L;经烧制后的陶粒,其重金属稳定化率最高达86.9%。

Aiming at the heavy metal polluted sediment of a project,five kinds of heavy metal stabilizers,seven kinds of flocculants and their dosages were screened and optimized,and a small-scale dehydration test of dewatering in geotextile tubes was carried out.Then,the sediment after dehydration was burned into ceramsite.The result shows that when the dosage of heavy metal stabilizer W-2 is 5%of the dry weight of sediment,the stabilization rates of As,Pb,Hg,Ni and Cu are 55.8%,86.9%,70.9%,79.0%and 75.9%.When the dosage of flocculant M603 is 0.3%of the dry weight of the sediment,the water content of sediment is reduced from 95%to 68.4%,and the COD value of supernatant is 32.5 mg/L,which meets the class V standard in GB 3838—2002 Environmental quality standards for surface water.The dewatering effect of the geotextile tubes is significant,and the concentration of suspended solids in the residual water is as low as 11 mg/L.The stabilization rate of heavy metal in fired ceramsite is as high as 86.9%.