烟气脱硫石膏改良围垦滩涂盐碱土研究

发布时间：2018-06-04 18:05

本文选题：烟气脱硫石膏 + 围垦滩涂盐碱土　；参考：《华东师范大学》2016年博士论文

【摘要】：随着人口增长、土地可利用面积减少,大面积围垦滩涂盐碱地成为我国滨海地区重要的后备土地资源,但目前部分滩涂地区盐碱化严重,寸草不生、长年荒芜,是围垦滩涂植被重建的最大障碍。改良围垦滩涂盐碱土对我国滨海地区的经济持续健康发展、生态环境保护等具有重要意义。如果依靠自然降雨淋洗和植被演替修复围垦滩涂盐碱地需要几十年才能完成。一百多年前就已利用石膏改良盐碱土。烟气脱硫石膏是燃煤电厂烟气脱硫后的副产物(主要成份为CaSO4· 2H20)。如果烟气脱硫石膏能够于沿海地区围垦滩涂盐碱地的改良,不仅为烟气脱硫石膏的应用开拓一个新的应用领域,也能够形成一套加快滩涂脱盐过程、改善滩涂土地质量的新技术,为解决沿海地区土地资源缺乏和滩涂可持续利用提供一个新的途径。本研究的目的是通过实验室和现场工程试验,确认(1)烟气脱硫石膏对长江口围垦滩涂盐碱土自然脱盐的加速作用；(2)对滩涂植被自然演替的推动作用,(3)对滩涂非盐生植物生长的影响,以及(4)使用烟气脱硫石膏的安全性,从而验证烟气脱硫石膏可以通过钙钠交换将滩涂自然脱盐过程缩短到数年内的科学假设。本项研究的主要结果如下：(1)烟气脱硫石膏加速围垦滩涂脱盐过程。采用烟气脱硫石膏(FGD-Gypsum)作为滩涂盐碱地土壤的改良剂,可以通过钙(Ca2+)钠(Na+)离子的交换,加速围垦滩涂盐碱地的自然脱盐过程。在上海沿海地区具有年平均降雨量1050 mm的条件下,烟气脱硫石膏可以降低土壤碱化度,尤其是60 Mg/ha的烟气脱硫石膏添加量可在2年内将土壤碱化度(ESP)降低至10%左右；(2)烟气脱硫石膏对围垦滩涂表层土壤的脱盐效果优于下层。烟气脱硫石膏施用6个月后即能不同程度的降低0-10 cm表层土层的碱化度,60 Mg/ha烟气脱硫石膏处理的土壤碱化度(ESP)无论南汇还是崇明均降至5%以下,而pH值则接近中性。下层土壤(10-30 cm)的ESP随烟气脱硫石膏用量的增加有不同程度的降低。与6个月测量的数据相比较,18个月后烟气脱硫石膏的脱盐效果更加明显；(3)烟气脱硫石膏降低有害盐离子含量,提高对植物有益盐离子含量。烟气脱硫石膏后降低了滩涂土壤pH值,减少了过量盐离子(水溶性Na+.Cl*和C032-+HC03-),钙、硫等元素显著升高。滩涂土壤尤其是表层土壤化学特性的改变,为滩涂生态恢复提供了基础；(4)烟气脱硫石膏促进了滩涂植被的多样性和演替。2年的植被样方调查表明,在烟气脱硫石膏添加的第二年,就会出现一般围垦多年才会生长的非盐生草本植物。烟气脱硫石膏促进了乔木的生长发育,植物的出苗率或存活率、根系长度、株高均大幅度提高。较高烟气脱硫石膏添加量,乔木植物的存活率较高；种植第三年,柳类植物的存活率接近90%；(5)烟气脱硫石膏施用对围垦滩涂盐碱土具有低的环境风险。烟气脱硫石膏不仅含有低的重金属含量,更多的Ca2+和S042-；而且只要施用一次,就可以获得明显的脱盐效果。除了Hg之外,我国烟气脱硫石膏重金属一般含量不高。在试验研究中,即便在烟气脱硫石膏添加量为60 Mg/ha时,土壤样品提取液中Hg均低于检测限(n=14)。建议采用《土壤环境质量标准》GB15618-1995的一级标准和《土壤环境质量标准(修订)》GB15618-2008,土壤无机物污染物的环境质量第二级标准值的最小值作为烟气脱硫石膏重金属的指导限值。特别关注烟气脱硫石膏中重金属元素Hg含量,一般不采用Hg超过标准值的烟气脱硫石膏,以确保生态安全。研究结果为大规模使用烟气脱硫石膏进行围垦滩涂盐碱土快速脱盐提供科学依据和工程经验。
[Abstract]:With the increase of population, the available area of land is reduced, and the saline alkali land of large area reclamation has become an important reserve land resource in the coastal areas of China. But at present, some beach areas are seriously salinized, uncultivated and desolate for years. Continuous healthy development and ecological environment protection are of great significance. If it takes decades to complete the reclamation of beach saline alkali land by natural rainfall leaching and vegetation succession, more than 100 years ago, gypsum has been used to improve saline alkali soil. FGD gypsum is a by-product of flue gas desulfurization (CaSO4 2H20) in coal-fired power plants. If FGD gypsum can be improved in coastal saline alkali land reclamation, it not only opens up a new application field for the application of FGD gypsum, but also forms a new technology to speed up the desalination process and improve the quality of the beach land, and provides a solution to the lack of land resources in coastal areas and the sustainable utilization of the beach. The purpose of this study is to confirm (1) the accelerated effect of FGD gypsum on natural desalination of saline alkali soil in the reclamation of the Changjiang Estuary by laboratory and field tests; (2) promoting the natural succession of the vegetation in the tidal flat, (3) the effect on the growth of non salt plants in the tidal flat, and (4) the safety of the use of FGD gypsum, The main results of this study are as follows: (1) the flue gas desulphurization gypsum (FGD gypsum) is used to reclaim the desalination process of the beach. The flue gas desulphurization gypsum (FGD-Gypsum) is used as a modifier in the saline alkali soil of the beach, and can be used by calcium (Ca2+ ) the exchange of sodium (Na+) ions accelerates the natural desalination process of reclamation of the saline alkali land in the beach. Under the conditions of 1050 mm of annual average rainfall in the coastal area of Shanghai, the FGD gypsum can reduce the degree of soil alkalinity, especially the addition of 60 Mg/ha FGD gypsum can reduce the soil alkalinity (ESP) to about 10% in 2 years; (2) flue gas. The desalination effect of Desulphurized Gypsum on the surface soil of the reclamation beach is better than that of the lower layer. After 6 months of application of FGD gypsum, it can reduce the alkalinity of 0-10 cm layer soil layer in varying degrees, and the soil alkalinity (ESP) of 60 Mg/ha FGD gypsum is reduced to less than 5% in both Nanhui and Chongming, while the value of the FGD is close to neutral. (10-30 The ESP of CM) decreased with the increase of the amount of FGD gypsum. Compared with the data measured in 6 months, the desalination effect of FGD gypsum was more obvious after 18 months. (3) FGD gypsum decreased the content of harmful salt ions and increased the content of beneficial salt ions to plants. After FGD gypsum, the pH value of the soil was reduced. The reduction of excessive salt ions (water soluble Na+.Cl* and C032-+HC03-), calcium, sulfur and other elements significantly increased. The changes in the chemical characteristics of the beach soil, especially the surface soil, provided a basis for the ecological restoration of the beach. (4) the FGD gypsum promoted the diversity of the vegetation in the tidal flat and the investigation of the vegetation sample for the.2 year showed that the FGD gypsum was used in the FGD gypsum. In the second years of addition, there will be non halophyte plants growing in general reclamation for many years. FGD gypsum promotes the growth and development of trees, plant emergence rate or survival rate, root length and plant height greatly increase. Higher FGD gypsum addition, the higher survival rate of arbor plants, third years of planting, willow plant The survival rate is close to 90%, and (5) the application of FGD gypsum has low environmental risk to the saline alkali soil in the reclamation beach. The FGD gypsum not only contains low heavy metal content, more Ca2+ and S042-, but also can obtain obvious desalination effect only once, except Hg, the general content of heavy metals in FGD gypsum in China In the experimental study, even when the addition of FGD gypsum is 60 Mg/ha, the Hg in the soil sample extract is lower than the detection limit (n=14). It is suggested to adopt the first grade standard of the soil environmental quality standard >GB15618-1995 and the soil environmental quality standard (Revised) >GB15618-2008, and the environmental quality of soil inorganic pollutants in the second grade standard. The minimum value of the value is regarded as the guiding limit of heavy metals in the flue gas desulphurization gypsum. It pays special attention to the Hg content of heavy metals in the flue gas desulfurization gypsum, and generally does not use the flue gas desulphurization gypsum with Hg above the standard value to ensure the ecological safety. The results provide scientific basis for the large-scale use of flue gas desulfurization gypsum for rapid desalting of the saline alkali soil in the reclamation beach. Evidence and engineering experience.
【学位授予单位】：华东师范大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S156.4

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