污染淤泥固化稳定化处理及种植性能试验

Experiments on stabilizing treatment of polluted silt solidification and planting performance

疏浚淤泥具有含水率高、固结难、体积大的特点,部分受到重金属污染,导致淤泥干化慢、利用难,且干化后土壤易板结,不利于植物生长。为了解决上述问题,以铜、铅、镉离子溶出超标的疏浚淤泥为研究对象,掺入纤维、石灰、粉煤灰、高岭土、硅酸钠、碳酸钠、硫酸铁和硫酸镁等多种材料进行固化稳定化试验和种植性能试验。结果表明:固化后土体渗透系数提高了2~3个数量级;8项重金属的浸出量有明显降低且达到标准要求;处理后土体上种植的羽衣甘蓝的生长速率更快,叶片外观更加鲜艳健康。确定10%(粉煤灰+石灰+高岭土+纤维)+6%(碳酸钠+硫酸铁)配比作为植物种植应用的优选方案,其种植的羽衣甘蓝重金属含量最少,8项重金属的浸出减少率之和超过其他4种配比,对N、P的吸收量较多。

Dredged silt has the characteristics of high moisture content, difficult consolidation and large volume, and polluted by heavy metals, leading to slow drying, hard utilization and soil hardening, which is unbeneficial of plant growing. To solve the above problems, dredged silt polluted by copper, lead, and cadmium was taken as a study object, which was mixed with fiber, lime, fly ash, kaolin, sodium silicate, sodium carbonate, ferric sulfate and magnesium sulfate. Then polluted silt stabilization and planting tests were performed. The results show that the permeability coefficients after soil solidification are increased by 2 or 3 orders of magnitude. Eight leaching amounts of heavy metals are obviously decreased, which can meet the national standards. The kale grown in solidified silt has faster growing rate with healthier leaf appearance. The optimum proportion of planting is 10% mixtures of fly ash, lime, kaolin, and fiber combined with 6% mixtures of sodium carbonate and ferric sulfate. Using the optimum scheme, the kale has lower heavy metal contents with higher reduction rate of heavy metal leaching amounts compared with other four groups, which can absorb more nitrogen and phosphorus.