Zheng G D, Chen T B, Gao D, Luo W
Laboratory of Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, PR China.
Water Sci Technol. 2004;50(9):75-82.
A large-scale sewage sludge composting experiment was conducted to develop an understanding of changes that occur to Pb chemical speciation, distribution and bio-availability during the course of composting. The four-stage Tessier sequential extraction method was employed to investigate the dynamics of heavy metal Pb speciation (exchangeable, bound to carbonates, bound to Fe-Mn oxides, bound to organic matter and sulphides, residual) during the course of sewage sludge composting. The concentrations of the total Pb and the five Pb fractions concentrations were increased during the whole stage of compost. However, the percentages of Pb distribution with respect to total Pb were changed in the following manner: exchangeable, bound to Fe-Mn oxides and bound to carbonates Pb with respect to total Pb were increased, while the percentages of bound to organic matter and sulphides, and residual Pb with respect to total Pb were decreased during composting. The data showed that the quantity of Pb in the less toxic portion, such as consisting of organic matter and sulphides bound and residual Pb, was increased, and that the contamination and bio-availability of heavy metal Pb in sewage sludge was reduced during the composting process.
进行了一项大规模的污水污泥堆肥实验，以了解堆肥过程中铅的化学形态、分布和生物有效性的变化。采用四阶段 Tessier 连续提取法研究了污水污泥堆肥过程中重金属铅形态（可交换态、碳酸盐结合态、铁锰氧化物结合态、有机物和硫化物结合态、残渣态）的动态变化。在堆肥的整个阶段，总铅浓度和五个铅组分的浓度均有所增加。然而，铅相对于总铅的分布百分比变化如下：可交换态、铁锰氧化物结合态和碳酸盐结合态铅相对于总铅的比例增加，而在堆肥过程中，有机物和硫化物结合态以及残渣态铅相对于总铅的百分比降低。数据表明，毒性较小部分的铅含量增加，如有机物和硫化物结合态以及残渣态铅，并且在堆肥过程中污水污泥中重金属铅的污染和生物有效性降低。
