人工湿地不同工艺对重金属的去除研究
发布时间：2019-06-20 07:18
【摘要】：重金属污染具有很严重的潜在危害,且重金属污染一旦发生很难消除,重金属在环境中通过食物链传递进行富集以致对食物链终极消费者人类的健康产生威胁。人工湿地作为污水处理的新型工艺,人工湿地有很强的抗冲击负荷能力,较好的净化水质能力并且其基建运行费用低廉的优点。人工湿地可以通过基质、植物、微生物对水中的重金属进行去除。人工湿地常见工艺有垂直潜流、水平潜流、表面流等形式。目前被广泛运用的人工湿地基质填料种类繁多。因此工程中针对不同污染物选用何种工艺、何种基质的研究很有必要。本文选用皂河人工湿地示范工程系列1~系列5五种复合人工湿地系统为研究对象,其中系列1为垂直潜流+水平潜流复合人工湿地系统、系列2为水平潜流+表面流复合人工湿地系统、系列3为垂直潜流+水平潜流+表面流复合人工湿地系统、系列4为水平潜流+表面流复合人工湿地系统、系列5为表面流+表面流复合人工湿系统。研究不同工艺、不同基质条件下人工湿地系统对水中Cd、Cr、Cu、Pb、Zn5中重金属的去除效果。探讨不同工艺下不同基质中重金属的沿程分布特征。分析系列5中(沙子+铝泥)基质对重金属的累积量与其理化性质的相关性。主要研究结果如下:1.人工湿地去除重金属机理(1)人工湿地系统中重金属与基质之间通过物理过程、化学过程、生物过程共同作用达到固定重金属的目的,且基质对重金属去除起主要作用。(2)人工湿地系统中重金属通过植物过滤、植物钝化、植物提取、植物挥发等方式实现重金属的去除,但植物对重金属的去除贡献不大。2.系列1~系列5复合人工湿地系统对重金属的去除效果(1)系列1系统~系列4系统复合型人工湿地对Cd、Cr、Cu、Pb、Zn5中重金属都有一定的去除效果。系列5除对Cu和Zn有显著释放现象外对Cd、Cr、Pb三种重金属也有一定的去除效果。各系列对Cd的去除率在75.00%~87.88%之间;对Cr的去除率在59.10%~73.10%之间;对Cu的去除率在24.14%~52.49%之间;对Pb去除率在57.79%~73.20%之间;对Zn去除率在27.86%~54.14%之间。(2)垂直潜流人工湿地对Cd、Cr、Pb的去除效果好于水平潜流和表面流人工湿地;多级复合型人工湿地对Cd、Cr、Pb的去除效果好于单级人工湿地;在表面流人工湿地中增加水力停留时间可提高对Cd、Cr、Pb的去除效果;垂直潜流和水平潜流人工湿地对Cu的去除差异不大。垂直潜流人工湿地对Zn的去除效果优于水平潜流人工湿地;垂直潜流+水平潜流复合型人工湿地对Cu和Zn的去除效果优于单种工艺的人工湿地。(3)表面流人工湿地对Cu和Zn均有释放现象,其可能原因为;Zn的可还原态高于除残渣态以外的其他形态,Cu的弱酸可溶态高于除残渣态以外的其他形态。由于人工湿地运行时间已久,水环境偏酸性,溶解氧较低使得Cu和Zn释放到水相中形成二次污染。3.人工湿地基质中重金属的沿程分布特征(1)重金属在各人工湿地基质中的平均含量大小依次为ZnCrPbCuCd。各种基质对Zn的累积含量在247.76mg/kg~438.18mg/kg之间;对Cr的累积含量在114.89mg/kg~127.30mg/kg;对Pb的累积含量在73.75mg/kg~77.62mg/kg;对Cu的累积含量在39.42mg/kg~68.43mg/kg;对Cd的累积含量在1.46mg/kg~10.15mg/kg。(2)垂直潜流工艺(豆石+碎石空心砖)基质、水平潜流工艺(沙子+炉渣+碎石空心砖)基质对Zn的累积效果较好;垂直潜流工艺(豆石+砾石)基质对Pb的累积效果较好;各工艺不同基质对Cu、Cr的累积效果差异不明显;水平潜流处理单元(沙子+炉渣+砾石)基质对Cd的累积效果好于(沙子+炉渣+碎石空心砖)基质,表面流处理单元(沙子+粉煤灰)基质对Cd的累积效果明显好于(沙子+煤渣)基质。(3)垂直潜流工艺(豆石+砾石)基质中Cd、Cr、Pb、Zn的含量与沿程距离相关性显著,(豆石+碎石空心砖)基质中Cd、Pb、Zn的含量与沿程距离相关性显著;水平潜流工艺(沙子+炉渣+砾石)基质中Cd、Cr、Zn的含量与沿程距离相关性显著,(沙子+炉渣+碎石空心砖)基质、(豆石+炉渣)基质中Cr、Cu、Pb、Zn的含量与沿程距离相关性显著,(沙子+砾石)基质中Pb、Zn的含量与沿程距离相关性显著;表面流工艺(沙子+粉煤灰)基质中Cr、Pb、Zn的含量与沿程距离相关性显著,(沙子+煤渣)基质中Cd、Cu、Pb、Zn的含量与沿程距离相关性显著。4.系列5人工湿地(沙子+铝泥)基质中重金属含量与其理化性质的相关性(1)(沙子+铝泥)基质中Cd、Pb的累积量与pH显著正相关,而(沙子+铝泥)基质中Cr、Cu、Zn的累积量与pH相关性不显著。(2)(沙子+铝泥)基质中Cd、Cr的累积量与有机质极显著负相关,(沙子+铝泥)基质中Cu、Pb、Zn的累积量与有机质显著负相关。(3)(沙子+铝泥)基质中Cd、Pb的累积量与电导率显著正相关,而(沙子+铝泥)基质中Cr、Cu、Zn的累积量与电导率相关性不显著。
[Abstract]:Heavy metal pollution is a serious potential hazard, and the heavy metal pollution is difficult to eliminate once the heavy metal pollution occurs, and the heavy metal is enriched in the environment through the food chain so as to threaten the health of the ultimate consumer of the food chain. The artificial wetland, as a new technology for sewage treatment, has the advantages of strong impact-resistant load capacity, better purification water quality and low cost of capital construction and operation. The artificial wetland can be removed by the heavy metal in the water through the substrate, the plant and the microorganism. The common process of artificial wetland has the form of vertical undercurrent, horizontal undercurrent, surface flow and so on. There are a wide variety of artificial wetland matrix fillers that are widely used at present. Therefore, what kind of process is selected for different pollutants in the project is necessary for the research of what kind of matrix. In this paper, five kinds of composite artificial wetland systems are selected as the research object of the first series of five composite artificial wetland systems of the sapo-river artificial wetland, in which the series 1 is a vertical undercurrent + horizontal undercurrent composite artificial wetland system, and the series 2 is a horizontal undercurrent + surface flow composite artificial wetland system. The series 3 is a vertical subsurface flow + horizontal undercurrent + surface flow composite artificial wetland system, and the series 4 is a horizontal undercurrent + surface flow composite artificial wetland system, and the series 5 is a surface flow and surface flow composite artificial wet system. The removal of Cd, Cr, Cu, Pb and Zn5 in water by artificial wetland system under different conditions and different substrate conditions was studied. The distribution of heavy metals in different substrates under different processes is discussed. The relationship between the accumulation of heavy metals and the physical and chemical properties of the matrix in the series 5 (sand + aluminum paste) was analyzed. The main results are as follows:1. In that artificial wetland system, the heavy metal mechanism (1) is remove by a physical process, a chemical process and a biological process through a physical process, a chemical process and a biological process to achieve the purpose of fixing heavy metal, and the substrate plays a major role in the heavy metal removal. (2) The heavy metals in the artificial wetland system can be removed by plant filtration, plant passivation, plant extraction, and plant volatilization. The removal effect (1) of the series 1-series 5 composite artificial wetland system on the heavy metals has a certain removal effect on the heavy metals in Cd, Cr, Cu, Pb and Zn 5 in the composite artificial wetland of series 1 to series 4. The series 5 has a certain removal effect on the three heavy metals of Cd, Cr and Pb in addition to the remarkable release of Cu and Zn. The removal rate of Cd is between 75.00% and 87.88%; the removal rate of Cr is between 59.10% and 73.10%; the removal rate of Cu is between 24.14% and 52.49%; the removal rate of Pb is between 57.79% and 73.20%; and the removal rate of Zn is between 27.86% and 54.14%. (2) The effect of the vertical subsurface flow constructed wetland on the removal of Cd, Cr and Pb is better than that of the horizontal undercurrent and the surface-flow constructed wetland; the removal effect of the multi-stage composite artificial wetland on the Cd, Cr and Pb is better than that of the single-stage artificial wetland, and the increase of the hydraulic retention time in the surface-flow artificial wetland can improve the Cd, The removal effect of Cr and Pb, and the difference of the vertical undercurrent and horizontal undercurrent constructed wetland to the removal of Cu. The effect of vertical undercurrent artificial wetland on Zn removal is superior to that of horizontal undercurrent constructed wetland, and the removal effect of vertical undercurrent + horizontal undercurrent composite artificial wetland on Cu and Zn is superior to that of single-process artificial wetland. (3) The surface-flow constructed wetland has the release of Cu and Zn, which may be due to the fact that the reducible state of Zn is higher than the other forms other than the residue state, and the soluble state of the weak acid of Cu is higher than the other forms other than the residue state. Since the operation time of the artificial wetland is long, the water environment is acidic and the dissolved oxygen is low, so that the Cu and Zn can be released into the water phase to form secondary pollution. The average content of heavy metals in the artificial wetland matrix is ZnCrPbCuCd. The cumulative content of Zn in various substrates was between 247.76 mg/ kg and 438.18 mg/ kg, the cumulative content of Cr was 114.89 mg/ kg-127.30 mg/ kg, the cumulative content of Pb was 73.75 mg/ kg-77.62 mg/ kg, the cumulative content of Cu was 39.42 mg/ kg-68.43 mg/ kg, and the cumulative content of Cd was 1.46 mg/ kg-10.15 mg/ kg. (2) The matrix of the vertical undercurrent process (bean stone + crushed stone hollow brick) and the horizontal undercurrent process (sand + slag + crushed stone hollow brick) matrix have good effect on the accumulation of Zn; the accumulation effect of the matrix of the vertical undercurrent process (bean stone + gravel) on the Pb is good; and the different substrates of each process are used for Cu, the cumulative effect of the cr is not significant; the accumulation effect of the horizontal undercurrent processing unit (sand + slag + gravel) matrix on the cd is better than that of the (sand + slag + crushed stone hollow brick) matrix, The cumulative effect of the surface flow treatment unit (sand + fly ash) matrix on Cd is obviously better than that of the (sand + coal cinder) matrix. (3) The content of Cd, Cr, Pb and Zn in the matrix of the vertical undercurrent process (bean stone + gravel) is significantly related to the distance along the range, and the content of Cd, Pb and Zn in the matrix of the (bean stone + gravel hollow brick) matrix is significantly related to the distance along the range. The content of Cd, Cr and Zn in the horizontal undercurrent process (sand + slag + gravel) matrix is significantly related to the distance along the range, and the content of Cr, Cu, Pb and Zn in the matrix of (sand + slag + crushed stone hollow brick) matrix and (bean stone + slag) matrix is significant with the distance along the range. The content of Pb and Zn in the (sand + gravel) matrix is significantly related to the distance along the range; the content of Cr, Pb and Zn in the matrix of the surface flow (sand + fly ash) is significant with the distance along the range, and the content of Cd, Cu, and Pb in the matrix (sand + coal slag) is significant. There is a significant correlation between the content of Zn and the distance along the range. The accumulation of Cd and Pb in the matrix of the series 5 artificial wetland (sand + aluminum paste) and its physical and chemical properties (1) (sand + aluminum paste) was positively correlated with the pH, while the accumulation of Cr, Cu, and Zn in the matrix (sand + aluminum paste) was not significant with the pH. (2) The accumulation of Cd and Cr in the (sand + aluminum paste) matrix was negatively correlated with the organic matter, and the accumulation of Cu, Pb and Zn in the matrix (sand + aluminum paste) was negatively correlated with the organic matter. (3) The cumulative amount of Cd and Pb in the (sand + aluminum paste) matrix is positively correlated with the conductivity, and the correlation between the accumulation of Cr, Cu and Zn in the matrix (sand + aluminum paste) and the conductivity is not significant.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703
本文编号：2503037
[Abstract]:Heavy metal pollution is a serious potential hazard, and the heavy metal pollution is difficult to eliminate once the heavy metal pollution occurs, and the heavy metal is enriched in the environment through the food chain so as to threaten the health of the ultimate consumer of the food chain. The artificial wetland, as a new technology for sewage treatment, has the advantages of strong impact-resistant load capacity, better purification water quality and low cost of capital construction and operation. The artificial wetland can be removed by the heavy metal in the water through the substrate, the plant and the microorganism. The common process of artificial wetland has the form of vertical undercurrent, horizontal undercurrent, surface flow and so on. There are a wide variety of artificial wetland matrix fillers that are widely used at present. Therefore, what kind of process is selected for different pollutants in the project is necessary for the research of what kind of matrix. In this paper, five kinds of composite artificial wetland systems are selected as the research object of the first series of five composite artificial wetland systems of the sapo-river artificial wetland, in which the series 1 is a vertical undercurrent + horizontal undercurrent composite artificial wetland system, and the series 2 is a horizontal undercurrent + surface flow composite artificial wetland system. The series 3 is a vertical subsurface flow + horizontal undercurrent + surface flow composite artificial wetland system, and the series 4 is a horizontal undercurrent + surface flow composite artificial wetland system, and the series 5 is a surface flow and surface flow composite artificial wet system. The removal of Cd, Cr, Cu, Pb and Zn5 in water by artificial wetland system under different conditions and different substrate conditions was studied. The distribution of heavy metals in different substrates under different processes is discussed. The relationship between the accumulation of heavy metals and the physical and chemical properties of the matrix in the series 5 (sand + aluminum paste) was analyzed. The main results are as follows:1. In that artificial wetland system, the heavy metal mechanism (1) is remove by a physical process, a chemical process and a biological process through a physical process, a chemical process and a biological process to achieve the purpose of fixing heavy metal, and the substrate plays a major role in the heavy metal removal. (2) The heavy metals in the artificial wetland system can be removed by plant filtration, plant passivation, plant extraction, and plant volatilization. The removal effect (1) of the series 1-series 5 composite artificial wetland system on the heavy metals has a certain removal effect on the heavy metals in Cd, Cr, Cu, Pb and Zn 5 in the composite artificial wetland of series 1 to series 4. The series 5 has a certain removal effect on the three heavy metals of Cd, Cr and Pb in addition to the remarkable release of Cu and Zn. The removal rate of Cd is between 75.00% and 87.88%; the removal rate of Cr is between 59.10% and 73.10%; the removal rate of Cu is between 24.14% and 52.49%; the removal rate of Pb is between 57.79% and 73.20%; and the removal rate of Zn is between 27.86% and 54.14%. (2) The effect of the vertical subsurface flow constructed wetland on the removal of Cd, Cr and Pb is better than that of the horizontal undercurrent and the surface-flow constructed wetland; the removal effect of the multi-stage composite artificial wetland on the Cd, Cr and Pb is better than that of the single-stage artificial wetland, and the increase of the hydraulic retention time in the surface-flow artificial wetland can improve the Cd, The removal effect of Cr and Pb, and the difference of the vertical undercurrent and horizontal undercurrent constructed wetland to the removal of Cu. The effect of vertical undercurrent artificial wetland on Zn removal is superior to that of horizontal undercurrent constructed wetland, and the removal effect of vertical undercurrent + horizontal undercurrent composite artificial wetland on Cu and Zn is superior to that of single-process artificial wetland. (3) The surface-flow constructed wetland has the release of Cu and Zn, which may be due to the fact that the reducible state of Zn is higher than the other forms other than the residue state, and the soluble state of the weak acid of Cu is higher than the other forms other than the residue state. Since the operation time of the artificial wetland is long, the water environment is acidic and the dissolved oxygen is low, so that the Cu and Zn can be released into the water phase to form secondary pollution. The average content of heavy metals in the artificial wetland matrix is ZnCrPbCuCd. The cumulative content of Zn in various substrates was between 247.76 mg/ kg and 438.18 mg/ kg, the cumulative content of Cr was 114.89 mg/ kg-127.30 mg/ kg, the cumulative content of Pb was 73.75 mg/ kg-77.62 mg/ kg, the cumulative content of Cu was 39.42 mg/ kg-68.43 mg/ kg, and the cumulative content of Cd was 1.46 mg/ kg-10.15 mg/ kg. (2) The matrix of the vertical undercurrent process (bean stone + crushed stone hollow brick) and the horizontal undercurrent process (sand + slag + crushed stone hollow brick) matrix have good effect on the accumulation of Zn; the accumulation effect of the matrix of the vertical undercurrent process (bean stone + gravel) on the Pb is good; and the different substrates of each process are used for Cu, the cumulative effect of the cr is not significant; the accumulation effect of the horizontal undercurrent processing unit (sand + slag + gravel) matrix on the cd is better than that of the (sand + slag + crushed stone hollow brick) matrix, The cumulative effect of the surface flow treatment unit (sand + fly ash) matrix on Cd is obviously better than that of the (sand + coal cinder) matrix. (3) The content of Cd, Cr, Pb and Zn in the matrix of the vertical undercurrent process (bean stone + gravel) is significantly related to the distance along the range, and the content of Cd, Pb and Zn in the matrix of the (bean stone + gravel hollow brick) matrix is significantly related to the distance along the range. The content of Cd, Cr and Zn in the horizontal undercurrent process (sand + slag + gravel) matrix is significantly related to the distance along the range, and the content of Cr, Cu, Pb and Zn in the matrix of (sand + slag + crushed stone hollow brick) matrix and (bean stone + slag) matrix is significant with the distance along the range. The content of Pb and Zn in the (sand + gravel) matrix is significantly related to the distance along the range; the content of Cr, Pb and Zn in the matrix of the surface flow (sand + fly ash) is significant with the distance along the range, and the content of Cd, Cu, and Pb in the matrix (sand + coal slag) is significant. There is a significant correlation between the content of Zn and the distance along the range. The accumulation of Cd and Pb in the matrix of the series 5 artificial wetland (sand + aluminum paste) and its physical and chemical properties (1) (sand + aluminum paste) was positively correlated with the pH, while the accumulation of Cr, Cu, and Zn in the matrix (sand + aluminum paste) was not significant with the pH. (2) The accumulation of Cd and Cr in the (sand + aluminum paste) matrix was negatively correlated with the organic matter, and the accumulation of Cu, Pb and Zn in the matrix (sand + aluminum paste) was negatively correlated with the organic matter. (3) The cumulative amount of Cd and Pb in the (sand + aluminum paste) matrix is positively correlated with the conductivity, and the correlation between the accumulation of Cr, Cu and Zn in the matrix (sand + aluminum paste) and the conductivity is not significant.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703
【参考文献】
相关期刊论文 前1条
1 朱亚琴;徐乐中;李大鹏;;给水厂污泥处置与资源化利用[J];广东化工;2011年12期
，本文编号：2503037
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