污泥和粉煤灰的循环利用及其对石漠化土壤质量的改善

摘要

Soil in karst rocky desert is applied with sludge-flyash composites of different sludge to flyash proportion in this experiment, and the effects of sludge-flyash composites on soil physicochemical properties, water-holding capacity and heavy metal accumulation in Festuca arundinacea are studied accordingly. The results show that the heavy metal contents like Cu, Mn, Zn and Cd in the sludge are remarkably decreased, the soil pH enhanced to about 7 and the soil physicochemical properties improved obviously after applying flyash; and that the soil water-saturation coefficients is enhanced by 1. 95 times, the time of water retention e-longated about 7d, the soil N, P increased and the biomass of Festuca arundinacea is also enhanced remarkably. So, it can yet be regarded as an effective method to ecologic rehabilitation for karst rocky desert. But it is not suitable to apply sludge repeatedly for the half-life period of the heavy metals in the sludge is long and the heavy metals are difficult to be thoroughly eliminated, and the heavy metals themselves are of serious eco-toxicity.%本文通过在石漠化土壤中添加不同配比的城市污泥—粉煤灰混合物,研究其对石漠化区域土壤理化性质、持水性能,及在该石漠化土壤上所种植的高羊茅生长和重金属积累的影响.结果表明:施用粉煤灰能显著降低污泥Cu、Mn、Zn和Cd等重金属的含量并使土壤的pH得到提高,明显改善土壤的理化性质；土壤饱和含水率比对照提高1.95倍,持水时间提高7d左右,能增加土壤的N、P养分,并显著提高高羊茅的生物量,不失为促进石漠化地区生态恢复治理的一种有效方法.但由于重金属在环境中半衰期长、彻底清除难和生态毒害大等特点,不宜长期反复施用富含重金属的城市污泥.