脱硫石膏改良滨海盐碱土的应用效果及环境风险研究

发布时间：2018-04-11 13:43

本文选题：脱硫石膏 + 滨海盐碱土　；参考：《上海应用技术大学》2017年硕士论文

【摘要】：近年来,脱硫石膏作为一种盐碱土改良剂,因其成本低、产量大、修复效率快而备受关注。在滨海区域,应用脱硫石膏改良滨海盐碱土,能缓解人多地少的矛盾,改善生态环境质量,促进滨海区域经济的健康可持续发展。脱硫石膏是电力、钢铁等行业烟气脱硫过程中的副产物。电厂、炼钢厂等工业企业属不同行业,其产生的烟气成分、脱硫工艺(或过程)、脱硫剂原料等有很大区别,导致产生的脱硫石膏差异较大,从而可能改良盐碱土的效果,同时可能带来潜在的环境风险问题。因此,本文选取了分别来自某炼钢厂和某燃煤电厂的两种不同类型的脱硫石膏,脱硫石膏改良滨海盐碱土的应用效果及环境风险研究。本研究的目的是通过土柱实验和田间实验,探究(1)脱硫石膏改良滨海盐碱土的脱盐过程、改良效果及影响因素(2)脱硫石膏改良滨海盐碱土的实际工程效果(3)脱硫石膏改良滨海盐碱土的生态安全中,脱硫石膏-土壤体系中重金属的变化规律。本研究的主要结果如下:(1)不同类型脱硫石膏改良滨海盐碱土的脱钠过程。土柱实验,采用不同类型的两种脱硫石膏A、B, 5个质量配比(0%、0.5%、1.0%、2.5%、5.0%), 9个处理,其结果表明:应用脱硫石膏A、B能加快土壤脱钠,在土壤脱钠的过程中,土壤淋出钠离子的浓度随时间而呈现先急剧下降后趋于平缓的变化,土壤淋出钠在土壤淋洗的前2天比较活跃;淋洗液中钙离子浓度越高,越利于脱硫石膏-土壤体系中钠离子的排出;土壤排钠、淋出钙与土壤饱和导水速率、脱硫石膏配比相关;脱硫石膏B对土壤的排钠效果明显优于A石膏。(2)脱硫石膏改良滨海盐碱土的影响因素。土柱实验中,应用脱硫石膏A、B均能改良滨海盐碱土,B石膏与A石膏相比,土壤饱和导水速率、排钠量、土壤透气速率分别增加了 0.58-0.89 倍、51.3%-74.0%、0.028-0.101 倍,土壤淋出钙的量、土壤 pH、碱化度(ESP)分别降低了 3%-14%、0.10-0.36个单元、66.7%-83.6%。B石膏对滨海盐碱土的改良效果优于A石膏,其原因为B石膏更少的杂质和更高的钙离子溶出速率。(3)脱硫石膏改良滨海盐碱土的田间实验。研究了改良效果更佳的脱硫石膏B的实际工程效果,结果表明,质量配比0.5%、1%、2.5%、5%的B石膏能降低土壤pH到8.0以下,适合植物生长,降低后的土壤pH能够稳定一段时间,且各处理配比之间无显著性差异(P0.05);施加B石膏可降低土壤碱化度,土壤碱化度随脱硫石膏配比的增加而显著降低(P0.05),随时间而显著减少(P0.05),配比2.5%、5%的B石膏可降低土壤碱化度到6%以下,达到非碱化度水平。田间实验中,脱硫石膏B能很好的改良滨海盐碱土。(4)脱硫石膏改良滨海盐碱土的环境风险。重点研究了脱硫石膏-土壤体系中重金属的变化规律,研究结果表明,脱硫石膏-土壤体系中,重金属As、Cd、Hg易向土壤深处迁移,Cr与所处环境的氧化还原状态有关,Pb易停留在土壤表层。综上所述,本文选择的两种脱硫石膏(A和B)均可以用于改良滨海盐碱土,其中某燃煤电厂的脱硫石膏B效果明显优于某炼钢厂的脱硫石膏A,主要源于其更少的杂质和更高的钙离子溶出效率,田间试验也证实了脱硫石膏B改良滨海盐碱土的效果较好;实验中,采用脱硫石膏B改良滨海盐碱土没有环境风险。本论文的工作为采用脱硫石膏改良滨海盐碱土提供了基础数据和相关技术支持,具有重要的环境意义。
[Abstract]:In recent years, the desulfurization gypsum as a soil improver, because of its low cost, high production efficiency, fast repair and concern. In the coastal region, application of gypsum improved saline alkali soil, can alleviate the contradiction between people and land, improve the ecological environment, promote coastal area economic sustainable development. Desulfurization gypsum is a by-product of electric power, iron and steel industry in flue gas desulfurization process. The power plant, steel plant and other industrial enterprises belong to different industries, the composition of flue gas desulfurization technology, desulfurization agent (or process), and other raw materials are very different, the difference caused by the guide of desulfurization gypsum is large, which could improve the saline alkali soil effect at the same time, the environmental risk may bring potential problems. Therefore, this paper selects two different types of desulfurization gypsum from a steel plant and a coal-fired power plant, the application effect of desulfurization gypsum improvement of coastal saline alkali soil and Study on the environmental risk. The purpose of this study is through the soil column experiment and field experiment, inquiry (1) desalination process desulfurization gypsum improvement of coastal saline alkali soil improvement effect and influence factors, (2) the actual engineering effect of desulfurization gypsum improvement of coastal saline alkali soil (3) ecological safety gypsum improved coastal saline alkali soil, change characteristics of heavy metals in the desulfurization gypsum soil system. The main results of this study are as follows: (1) sodium removal process of different types of gypsum improved coastal saline soil. The soil column experiment, using two kinds of gypsum A, different types of B, 5 mass ratio (0%, 0.5%, 1%, 2.5%, 5%) 9, processing, the results show that the application of desulfurization gypsum A, B can speed up the removal of sodium in soil, soil and sodium in soil, leaching concentration of sodium ion with time and showed gradual changes to decreased sharply after soil leaching of sodium in soil leaching than 2 days ago The more active; the eluent concentration of calcium ions is higher, more conducive to the discharge of sodium ion desulfurization gypsum soil system in the soil; the excretion of sodium, calcium and leaching of soil saturated water rate, ratio of gypsum; gypsum B on sodium excretion effect of soil was better than that of A gypsum. (2) factors affecting removal sulfur gypsum improvement of coastal saline alkali soil. Soil column experiment, application of desulfurization gypsum A, B can improve saline alkali soil, compared with B and A gypsum gypsum, soil saturated water rate and sodium excretion amount, soil aeration rate were increased by 0.58-0.89 times, 51.3%-74.0% times, 0.028-0.101, soil leaching amount of calcium. Soil pH, alkalinity (ESP) were decreased by 3%-14% 0.10-0.36, a unit of 66.7%-83.6%.B gypsum on coastal saline alkali soil improvement effect is better than that of A gypsum, the reason for the dissolution rate of impurity B gypsum less and higher calcium. (3) the desulfurization gypsum improvement of coastal saline alkali soil field Among the experiments. The practical engineering effect, study the improvement effect of better desulfurization gypsum B showed that the mass ratio of 0.5%, 1%, 2.5%, 5% B gypsum can reduce soil pH below 8, suitable for plant growth, soil pH decreased to a stable period of time, and there was no significant difference between each treatment ratio (P0.05) B; applying gypsum can reduce soil alkalization, soil alkalization degree decreased with the increase ratio of gypsum decreased significantly (P0.05), was significantly reduced with time (P0.05), the ratio of 2.5%, 5% B gypsum can reduce the soil alkalinity below 6%, to achieve non alkalinity levels. Field experiments. The desulfurization gypsum B to improve saline alkali soil is very good. (4) the environmental risk of desulfurization gypsum improvement of seashore saline soil. Focus on the changes of heavy metal desulfurization gypsum soil system, the results show that the desulfurization gypsum soil system, heavy metals As, Cd, Hg easy to soil The soil depth migration, Cr and the redox state of Pb, easy to stay at the surface of the soil. In conclusion, this paper chooses two kinds of desulfurization gypsum (A and B) can be used to improve the saline alkali soil, in which a steel plant in a coal-fired power plant desulfurization gypsum desulfurization gypsum B is better than A, efficiency the dissolution is mainly due to its less impurities and higher calcium ion, the field experiments also confirmed that better desulfurization gypsum B coastal saline alkali soil improvement effect; in the experiment, the desulfurization gypsum B improvement of coastal saline alkali soil without environmental risk. The work of this paper is using the gypsum improved coastal saline soil and provide basic data and related technical support, are of significance to the environment.

【学位授予单位】：上海应用技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S156.42;TQ177.375

【参考文献】