重金属Cu、Cd在施用城市污泥的改良土壤中的迁移转化研究

发布时间：2018-05-05 13:12

本文选题：城市污泥 + 黄土　；参考：《兰州大学》2015年硕士论文

【摘要】：将城市污泥施用于黄土不仅能够补充黄土中缺乏的有机质和植物营养元素,促进黄土熟化,而且能够解决城市污泥的处置问题。本文将城市污泥施入黄土中,称之为改良土壤,先通过吸附解吸试验研究了改良土壤对Cu的固定能力及其影响因素,再通过小麦盆栽试验研究了Cd在改良土壤一小麦系统中的迁移转化特征。论文主要研究结果如下：(1)在试验设计的Cu初始添加浓度范围内(25-400mg·L-1),添加梯度城市污泥(0%、4.3%、8.1%、16.2%、20.9%、26.1%、28.9%、32.6%、42.5%、48.8%)的改良土壤对Cu的吸附量基本都达到了饱和,而且城市污泥含量越高的改良土壤,其最大吸附量越大；而且同一吸附量下,城市污泥含量越高的改良土壤的解吸量越小,说明城市污泥含量越高的改良土壤对Cu的固定吸附量越大。由此可得,施加城市污泥增强了供试土样对重金属Cu的固定能力,可以降低重金属Cu的活性。(2)黄土中施加0.5%城市污泥,可以适当调节黄土的强碱性；施加0.5%城市污泥后,改良土壤中有机质含量增加31.8%,EC上升35.9%,全氮含量增加11.5%,说明施加城市污泥补充了黄土中缺少的植物营养成分；而且改良土壤中相关重金属的含量也增加了,但仍在《土壤环境质量标准》(GB 15618-1995)的相关限值以内。(3)重金属Cd同一处理水平下,施加0.5%城市污泥组小麦的出苗率、株高、生物量(根、茎叶、麦穗干重)以及产量均比未施加污泥组的高,其中麦穗干重差别最大,施污泥组小麦穗干重比未施污泥组平均增加了59%,说明施加0.5%污泥的黄土更适合小麦的生长发育,其产量也增加了。(4)重金属Cd同一处理水平下,施污泥组土壤中Cd的可交换态含量比未施污泥组的平均降低了0.2309mg·kg-1；但碳酸盐结合态、铁锰氧化态以及有机结合态Cd的含量比未施污泥组的增加,其中碳酸盐结合态含量平均增加了0.3320 mg·kg-1,铁锰氧化态含量平均增加了0.0631 mg·kg-1,有机结合态含量平均增加了0.0029 mg·kg-1; Cd的残渣态含量比未施加污泥组略有减少,平均减少了0.1033mg·kg-1。综合考虑Cd的5种赋存形态含量变化可得：施加0.5%城市污泥的改良土壤中Cd的活性比未施加污泥的增高。(5)对比重金属Cd同一处理水平下施污泥组与未施污泥组小麦各部位Cd含量可知,施污泥组小麦茎叶、颖壳、籽粒中Cd的含量均高于未施污泥组,说明施加0.5%城市污泥促进重金属Cd在小麦地上部分的积累,由此可得,城市污泥农用可能会带来一定的健康风险。
[Abstract]:The application of municipal sludge to loess can not only supplement the lack of organic matter and phytotrophic elements in loess, but also promote the maturation of loess and solve the problem of disposal of municipal sludge. In this paper, the application of municipal sludge into loess is called improved soil. Firstly, the fixation ability of improved soil to Cu and its influencing factors are studied by adsorption and desorption test. The characteristics of CD migration and transformation in improved soil-wheat system were studied by pot experiment. The main results of this paper are as follows: (1) in the experimental design of the initial Cu addition concentration range of 25-400mg / L ~ (-1), adding gradient urban sludge (4.3mg / L), the improved soil with higher sludge content in the city has basically reached saturation for Cu, and the improved soil with higher sludge content in the city has reached the saturation of Cu adsorption in the improved soil, which is about 20.926.1 ~ 26.1and 28.92.62.5 ~ 48.8cm ~ (-1), and the higher the sludge content in the city is, the higher the sludge content in the city is. The larger the maximum adsorption capacity is, and the smaller the desorption capacity of the improved soil is, the higher the sludge content is, the higher the fixed adsorption amount of Cu in the improved soil is. It can be concluded that the application of municipal sludge enhances the fixation ability of soil samples to heavy metal Cu, and can reduce the activity of heavy metal Cu in loess by adding 0.5% municipal sludge, which can adjust the strong alkalinity of loess properly, and after 0.5% municipal sludge is applied, The content of organic matter in improved soil increased by 31.8% and the content of total nitrogen increased by 35.9%, indicating that the application of municipal sludge replenished the plant nutrients lacking in loess, and the contents of related heavy metals in the improved soil also increased. However, under the same treatment level of CD, which is still within the relevant limit value of "soil Environmental quality Standard" (GB15618-1995), the seedling emergence rate, plant height, biomass (root, stem and leaf) of wheat treated with 0.5% urban sludge were studied. The dry weight of wheat ear and yield were higher than that of no sludge group, and the difference of dry weight of wheat ear was the greatest, and the dry weight of wheat ear increased by 59% in sludge application group, which indicated that the loess with 0.5% sludge was more suitable for wheat growth and development. Under the same treatment level of heavy metal CD, the exchangeable state content of CD in the soil of the sludge application group was lower than that of the untreated sludge group, but the carbonate bound state was decreased. The contents of Fe and mn oxidized and organic bound CD were higher than those of untreated sludge. The content of carbonate-bound state increased by 0.3320 mg 路kg ~ (-1), the content of ferromanganese oxide increased by 0.0631 mg / kg ~ (-1), the content of organic bound state increased by 0.0029 mg / kg ~ (-1), and the residual state content of CD decreased slightly than that of untreated sludge group, and the average content of 0.1033mg _ (kg-1) was decreased. Considering the changes of CD contents in five forms of occurrence, it can be concluded that the activity of CD in the improved soil with 0.5% municipal sludge is higher than that in the untreated soil.) compared with heavy metal CD, the activity of CD in the improved soil is smaller than that in the sludge group and the unapplied sludge group under the same treatment level of heavy metal CD. CD content in different parts of wheat can be seen. The content of CD in stem, leaf, glume and grain of wheat treated with sludge was higher than that of untreated sludge, which indicated that the application of 0.5% municipal sludge could promote the accumulation of heavy metal CD in wheat. Urban sludge farming may bring some health risks.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703;X53

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