南京市城市污泥和工业污泥中典型矿质元素含量和形态分布研究

Contents and distribution of mineral elements in urban and industrial sludges in Nanjing

采用三态连续提取法研究南京市部分城市污泥和工业污泥中典型矿质元素的含量和形态分布,为污泥资源化的合理利用提供科学参考。结果表明,污泥总体呈高有机质、高氮磷、低K的相似性,但其理化性质如阳离子交换容量(CEC)、pH等有差异。污泥中不同矿质元素含量差异也较大,Fe的浓度最高,其次是Mg、Zn;且不同污泥间同一矿质元素含量的差异也较大。各元素的形态分布有一定差异,Cu主要分布在可氧化态,其酸溶/交换态和可还原态的百分率很低;Zn三态分布均较高;Mg、Mn主要分布在酸溶/交换态;Fe主要分布在残渣态。但三种提取形态百分率之和除Fe外均超过50%。研究同时表明,城市污泥和工业污泥中矿质元素形态分布无显著性差异。

This paper aims to introduce the authors＇ investigation on the contents and distribution of mineral elements in the urban and industrial sludge in Nanjing City. The sample sewage sludges tested in this paper were collected from Suojincun sewage treatment plant, Jinlin Petrifaction Co, Ltd. wastewater treatment plants, Jianglin Beer Industry wastewater treatment plants and Jinyinxin Paper Industry wastewater treatment plants in Nanjing. As we know, mineral elements are necessary for the plant growth and development. The content of mineral elements in sludge can help to provide information on their bioavailability than their total contents. The physicochemical properties of the sludge and the total contents of the mineral elements and their fractions by BCR sequential exti＇action were investigated. As a result, it was found that the sludge contains organic matters, such as TN, TP to a high degree but K to a low degree. Their CEC and pH varied greatly. The difference of the mineral contents in the sludge samples collected was significant. So were the difference in the kinds of the mineral elements in the different sludge samples, Generally speaking, Fe was the highest, and followed by Mg, Zn. The fractions obtained by the sequential extraction procedure indicate that Zn fractions were affected by the source of the sludge samples, and their percentage were all above 10% ; Cu was principally distributed in the oxidizable fraction; Mg and Mn were principally distributed in the acid soluble/exchangeable fraction and Fe was mainly in the residual fraction. The percentage of the soluble/exchangeable fraction ofZn, Mg, Mn were all ahove 10%, while that of Cu, Fe below 10%. The sum of the percentages of three fractions of mineral elements except Fe were all above 50%, and even beyond 90% tbr some elements. Therefore, it can be said that sewage sludges have higher nutritional value for plant growth, which is highly potential for agricultural development.