粉煤灰对堆肥重金属有效性及其在环境中迁移转化的影响

发布时间：2018-04-02 20:41

本文选题：畜禽粪便　切入点：堆肥　出处：《安徽大学》2017年硕士论文

【摘要】：畜禽粪便中重金属含量严重超标,这些重金属极易随施肥进入农田土壤,长期施用使得土壤中Cu、Zn等重金属含量日益增加;且重金属会随土壤径流污染地表及地下水,危及人类健康。本研究以廉价易得的粉煤灰为钝化剂,通过堆肥试验、pH-依赖性浸出试验、盆栽实验及室内柱淋溶实验研究粉煤灰对畜禽粪便中重金属有效性的影响;探究粉煤灰对堆肥过程重金属的钝化作用,分析有机肥中重金属的浸出特性,评价土壤-蔬菜系统中重金属的迁移及对人体的影响,模拟有机肥重金属在土壤中的淋溶特征,为畜禽粪便的资源化无害化和降低畜禽粪便重金属的环境效应利用提供理论依据及技术支持。主要结论如下:(1)堆肥过程中添加粉煤灰可降低Cu、Zn的有效性并促进腐殖质由水溶态向更为稳定状态转化。堆肥过程腐殖质总量降低,HA/FA比值增加。腐殖质的变化影响Cu、Zn的有效性,堆肥过程Cu和Zn的有效态含量均有所降低,Cu-OM 和 Cu-RES 的分配率达 90%以上。Zn-Fe/Mn OX、Zn-OM 和 Zn-RES 的分配率达75%以上,较为稳定。添加粉煤灰的F5组有机结合态Cu分配率由82.82%增至84.18%,残渣态Zn较堆肥前后增幅为18.97%,表明粉煤灰对锌的钝化效果较好。(2)堆肥的浸出实验表现出很强的pH依赖性,中性条件下(pH6-8),Cu、Zn和DOM的浸出浓度低;在酸性(pH6)和碱性(pH8)环境中,Cu、Zn和DOM的浸出浓度高,且在实验pH范围内,Cu的浸出浓度整体高于Zn的浸出浓度。添加钝化剂影响重金属的浸出特性,Cu、Zn浸出行为与实验材料及DOM的浸出浓度有关。在3-9的pH范围内,添加粉煤灰可降低Cu和Zn的浸出浓度。(3)盆栽实验表明施用有机肥可显著增加植物鲜重、株高和根长,但不同处理条件下油菜的重金属富集系数不同,添加粉煤灰堆肥可以降低油菜生物富集系数。盆栽后的HE、HM较盆栽前均降低了 30%以上,有机结合态Cu显著降低,铁锰氧化物结合态Zn显著增加。与施用不含钝化剂的堆肥相比,施用含钝化剂的盆栽处理中铁锰氧化物结合态的铜含量显著较高;且添加粉煤灰可能会影响土壤中腐殖质结构,进而影响土壤肥力。(4)室内柱淋溶模拟实验表明添加粉煤灰可减少土壤中重金属浸出;淋溶前后土壤中重金属总量显著降低,其中施10%F5肥的处理淋溶前后土壤中Cu、Zn含量变化差异不显著。滤液中Zn的淋溶浓度远高于铜的淋溶浓度。Cu和Zn在浸出实验中的行为一致,均由高到低减小,粉煤灰的多孔结构使得5%粉煤灰堆肥处理中重金属淋溶浓度较CK堆肥处理偏低。
[Abstract]:The content of heavy metals in feces of livestock and poultry exceeded the standard seriously, these heavy metals could easily enter farmland soil with fertilization, and the contents of heavy metals such as Cu, Zn and other heavy metals in soil would increase day by day, and heavy metals would pollute the surface and groundwater with soil runoff.Endanger human health.In this study, the effects of fly ash on the availability of heavy metals in animal feces were studied by composting experiment, pH dependent leaching test, pot experiment and column leaching experiment.The passivation effect of fly ash on heavy metals in compost process was studied, the leaching characteristics of heavy metals in organic manure were analyzed, the migration of heavy metals in soil-vegetable system and their effects on human body were evaluated, and the leaching characteristics of heavy metals in soil were simulated.It provides theoretical basis and technical support for the harmless utilization of animal manure and the reduction of environmental effects of heavy metals in livestock and poultry feces.The main conclusions are as follows: (1) addition of fly ash in composting process can reduce the availability of Cu ~ (2 +) Zn and promote the transformation of humus from water-soluble state to more stable state.The total humus content decreased and the ratio of HA / FA increased during composting.The available state contents of Cu and Zn in composting process were reduced to more than 90%. The distribution rates of Zn-FeR / Mn-OXOXO / Zn-OM and Zn-RES were more than 75%.The distribution rate of organic bound Cu in F5 group increased from 82.82% to 84.18%, and the residual Zn increased 18.97% compared with that before and after composting, indicating that fly ash has a strong pH dependence on the leaching of zinc passivated compost.The leaching concentrations of Cu ~ (2 +) and Cu ~ (2 +) were lower in neutral condition than those in pH _ (6) and alkaline (pH _ (8)), and the leaching concentration of Cu _ (2 +) was higher than that of Zn in the range of experimental pH (pH = 6 ~ (8)) and alkaline (pH _ (8)) respectively, and the leaching concentration of Cu ~ (2 +) was higher than that of Zn in the pH range of experiment.The influence of passivating agent on the leaching characteristics of heavy metals is related to the leaching concentration of DOM and experimental materials.In the range of 3-9 pH, adding fly ash decreased the leaching concentration of Cu and Zn. The pot experiment showed that organic fertilizer could significantly increase plant fresh weight, plant height and root length, but the enrichment coefficient of heavy metals in rape was different under different treatment conditions.The addition of fly ash compost can reduce the bioaccumulation coefficient of rape.After pot planting, HM decreased by more than 30%, organic bound Cu decreased significantly, and Fe and mn oxide bound Zn increased significantly.Compared with the compost without passivating agent, the copper content of iron-manganese oxide in potted plants with passivating agent was significantly higher than that of compost without passivator, and the humus structure in soil might be affected by adding fly ash.The indoor column leaching simulation experiment shows that the addition of fly ash can reduce the heavy metal leaching in the soil, and the total heavy metal content in the soil before and after leaching is significantly reduced.There was no significant difference in the content of Cu + Zn in soil before and after leaching with 10 fertilizer.The leaching concentration of Zn in filtrate was much higher than that of copper. The behavior of Cu and Zn in leaching experiment was the same, which decreased from high to low. The porous structure of fly ash made the leaching concentration of heavy metal in 5% fly ash compost lower than that in CK compost.
【学位授予单位】：安徽大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53;X713

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