【摘要】 污泥堆肥工艺是实现污泥减量化,无害化和资源化的重要手段。文章考察了污泥在堆肥前后四类重金属(铜、锌、铅和镉)形态的变化。结果显示,铜、锌、铅和镉在堆肥前后的总量变化不大,Cu、Zn主要以有机结合态和残渣态形式存在,而Pb、Cd主要以残渣态形式存在。堆肥处理过程中可交换态重金属都呈下降趋势,但各种重金属的可交换态变化幅度不同,以Zn和Cd下降幅度最大,Zn的可交换态由堆肥前的10.5%下降到堆肥后的4.8%;Cd的可交换态从堆肥前的3.2%下降到堆肥后的1.8%,下降比例超过和接近50%。随着向土壤中添加污泥及堆肥量的增加,小麦植株地上和地下部分重金属含量也相应增加,且地下部分含量高于地上部分,小麦中重金属含量在地下部与地上部之间的比值恒定,特别是Pd,Cd的地上和地下部分浓度比可分别达到130和15～20,经堆肥处理的污泥可以降低小麦对其中重金属的吸收。将污泥及堆肥腐熟品添加至石油污染土壤中,与对照相比土壤中的石油烃含量有一定幅度的下降,最大下降幅度为19.6%。处理一个月后重金属含量及其形态变化不大,Zn具有向铁锰氧化态转化的趋势。更多还原

【Abstract】 Composting is an important method to dispose sewage sludge. Changes of speciation of 4 heavy metals including copper,zinc,lead and cadmium in sewage sludge during composting and remediation of petroleum-contaminated soil were studied. Results showed that total copper,zinc,lead and cadmium hardly changed during composting,with Cu and Zn existed in the form of organic-combined state and Pb,Cd in the form of residual state. Their exchangeable form decreased, with different reducing rates in different heavy metals. The exchangeable zinc reduced from 10.5% to 4.8%,and exchangeable cadmium from 3.2% to 1.8% during composting,with rate of reduction over and close to 50% respectively. With increasing amount of sludge and compost added to the soil,heavy metal content in wheat increased with higher content in upper-ground part of wheat compared to underground part. Ratio between upper-ground part and underground part was constant with higher value of 130 and 15~20 for Pb and Cd respectively. With addition of sludge and compost to petroleum-contaminated soil, speciation of heavy metals did not change much,but petroleum content in soil decreased in some extent compared to the control,with the highest rate of 19.6%. Zn tended to change to Fe-Mn oxides combined form during bioremediation process.更多还原