Stabilization of Chromium by Humus in Aerobic Composting of Food Wastes and Chromium-Contaminated Soil

摘要

Experiments on aerobic composting of food wastes and chromium-contaminated soil at ratio of 3:1 on dry weight were carried out. The changes of humification index (HI) and chromium speciation during composting were investigated, and the availability of compost to plant was also discussed. The result indicated that the percentage of humic acid (HA)-bound and fulvic acid (FA)-bound chromium in organic-bound chromium increases to 72.1%from primary 15.1%. It showed that FA played a major role on the stabilization of chromium that FA-bound chromium content was higher than HA-bound chromium. The content of phytoavailable chromium was decreased from 162.4mg/Kg to 54.75mg/Kg during the composting. The leaching chromium concentration of composting product was below 2mg/L. Composting process can reduce the toxicity and mobility of chromium in soil.