| 摘要: |
| 通过土柱淋溶试验，分析了市政污泥在矿山土壤改良中重金属污染风险，探讨了市政污泥用于矿区土壤改良的可行性，并确定了土壤污泥最佳混掺比例。结果表明：景山高岭土矿区土壤除速效磷含量较高外，其余养分含量分级为四—五级，即“低—很低”；市政污泥除速效钾含量较低外，其余养分含量分级均远大于一级“很高”；永春污水处理厂污泥为B级农用污泥，可施用于油料作物、果树、饲料作物、纤维作物，不能施用于蔬菜、粮食作物；按各处理配比进行污泥的适量施用造成地下水污染风险较小；综合考虑土壤肥力及重金属污染因素，该矿区最佳土壤、市政污泥干重混掺比为5∶2。 |
| 关键词: 市政污泥 矿区 土壤改良 污染风险 最佳配比 |
| DOI：10.7515/JEE182008 |
| CSTR：32259.14.JEE182008 |
| 分类号: |
| 基金项目:国家自然科学基金项目（41572333）；国土资源部资助项目（国土资发[2011]183文）；福建省社会发展重点项目???（2013Y0006） |
| 英文基金项目:National Natural Science Foundation of China (41572333); Ministry of Land and Resources (Doc NO.MOLAR [2011]183); Social Development Major Project of Fujian Province, China (2013Y0006) |
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| The pollution risk assessment and matched analysis of municipal sullage being used for soil improvement in mining area |
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LUO Dafu
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1. The 197 Geological Prospecting Team of Fujian Province, Quanzhou 362011,China
2. Anhui University of Science and Technology, Huainan 232001, China
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| Abstract: |
| Background, aim, and scope The abandoned mine soil is often poor, which is not conducive to the restoration of vegetation. The municipal sludge has high nitrogen, phosphorus, potassium and organic matter, but also contains high content of heavy metal pollutants. If the municipal sludge is not used properly, it is likely to cause second pollution of the soil. At present, the research for soil improvement using municipal sludge, is mainly concentrated on the soil of desertified or salinized grassland and farmland, and there is few studies focusing on the wasteland soil improvement in mining area, especially finding the balance relationship between the dosage of waste sludge and the risk of heavy metal pollution. The purpose of this study is to analyze the risk of heavy metal pollution using municipal sludge to improve the waste land in the mining area, and to determine the optimal mixing ratio of soil and sludge. Materials and methods In this study, the sludge of Yongchun sewage treatment plant in Quanzhou city and the mining stripping soil of Jingshan kaolin mine in Yongchun county of Quanzhou City were selectexsd as the test materials. The experiment was carried out in leaching columns. The height of the soil column is 30 cm with a diameter about 10 cm, and a collection pool of leachate is located at the bottom of the soil column, and a protective cover is arranged around the soil column in order to prevent water evaporation. The bottom of the soil column is filled with slag with a thickness of 10 cm, the upper part of which was filled with the mixture of soil and sludge. The material should be compacted according to the monitoring of soil water content and bulk densitysoil. Each treatment was done in 5 groups. The material was irrigated with deionized water for 20 mm daily, and continued for 15 days. On the twentieth day, the mixture in the soil column was mixed evenly, and each repetition in each group was taken with one sample, and a total of 20 samples were taken, and 20 filtrate samples were also obtained at the same time. The whole experiment consisted of 4 groups. Experiment 1 (LT1), the mixing proportion of soil and dry sludge was 5∶1; test 2 (LT2), the mixing proportion of soil and dry sludge was 5∶2; test 3 (LT3), the mixing proportion of soil and dry sludge was 5∶3; 4 (LT4), test mixing ratio of sludge to soil dry weight was 5∶4. Before the test, the initial value of the indicators of soil and sludge including physical and chemical properties, soil fertility, trace elements and organic matter were determined. After the test ended, the end point value of the indicators of soil column filler and the content of trace elements in the leachate should be monitored. Results The
data shows that the concentration of Zn in sludge is (2817 ± 99.30) mg ∙ kg−1, and the concentration of Cu is (602.20 ± 11.40) mg ∙ kg−1, which exceed the class A sludge concentration limit of the standard “sludge disposal of agricultural muddy town sewage treatment (CJ/T 309—2009)”, but the content of heavy metals did not exceed the limit of class B sludge concentration. The leachate quality of the four kinds of treatment can meet the water quality standard set by the national GB / T 14848—93. In the four treatments, the content of Zn in the mixed material in LT3 and in LT4 are higher than 500 mg ∙ kg−111, which beyond the standard of class Ⅲ in soil environmental quality standard (GB 15618—1995), and the content of heavy metal in the mixture of LT1 and LT2 can also meet the standard requirements of class Ⅲ, but LT2 is relatively higher than others in nutrients. Discussion The test results show that the experimental sludge was class B agricultural sludge, which can not be applied to vegetables and food crops; the nutrient content of four kinds of treatment is increased with the increase of sludge content, but when the proportion of soil and sludge is greater than 5∶2, the content of heavy metals in mixed blends exceed the standard. Conclusions The classification of soil nutrient content of Yongchun Jingshan kaolin mining area is four to five, that is low to very low; The nutrient content of sludge is classified as the first grade in Yongchun sewage treatment plant, which is very high; The experimental sludge is class B agricultural sludge, which can be applied to oil crops, fruit trees, feed crops, fiber crops, but can not be used for vegetables, grain crops. The application of municipal sludge in accordance with the proportion of each treatment resulted in less risk of groundwater pollution. The optimum mixing ratio of soil and sludge dry weight was 5∶2. Recommendations and perspectives Because of the low content of available potassium in the soil and municipal sludge, it is necessary to add a certain amount of potassium fertilizer to the mixture when applied according to the optimum proportion of soil and sludge. In addition, in order to prevent the accumulation of toxic and harmful substances such as heavy metals, and ensure adequate nutrients in the soil, the pollutants and nutrients content of sludge, soil and crops should be regularly monitored. |
| Key words: municipal sludge mining area soil improvement pollution risk optimum proportion |
