【作者】 杨昌民；

【导师】 闫澍旺；

【作者基本信息】 天津大学 ， 岩土工程， 2006， 博士

【摘要】 脱水污泥的填埋处理是比较符合中国国情的处置方式。本文从环境岩土工程的角度,采用试验研究、理论分析和数值模拟的方法,对脱水污泥的环境与工程性质进行了系统的研究,并以粉煤灰、粉质粘土和石灰等作为固化材料,对脱水污泥的填埋特性进行了改良,内容如下:对当前国内外脱水污泥的处置方法进行了比较研究,总结了各种处置方法的优缺点,提出污泥填埋是比较适合中国国情的处置途径。针对污泥填埋存在的技术难题,提出用固化材料改良脱水污泥的填埋特性,进行单独填埋。石灰、粉质粘土和粉煤灰的加入,改良了污泥的填埋特性。经过一定时间的养护,固化污泥强度完全可以达到填埋处理标准。通过对体积安定性观察,发现石灰的加入对于提高试样的体积安定性有利。通过正交试验,发现在本研究中,质量相同的粉质粘土的固化效果优于粉煤灰,原因可能是粉煤灰的活性在污泥这种特殊的环境下没有被激发出来。微观结构的研究表明,固化材料的加入提高了污泥密实度。土颗粒面积和土颗粒周长是两个可以有效应用与土体微观结构研究定量研究的参数。土体的密实度评价可以通过土体微观结构中的面积参数来实现,较大的面积参数对应着土体较大的密实度,土颗粒周长可以用来对土颗粒之间的联系进行定量的描述,周长小的土体联结更紧密。不同的固化材料对渗滤液影响的差异较大。添加石灰的填埋柱的渗透性最大,渗滤液的产生量最大,PH值最高,渗滤液的COD值远高于其它污泥填埋柱。石灰一方面使固化污泥中的Cu离子趋于不稳定;另一方面,对污泥中的Zn离子具有固化作用。而粉煤灰和粉质粘土对渗滤液的影响则相对较小。对不同地质条件下污染物的运移规律进行了数值模拟。研究表明,吸附函数、渗透系数和水力梯度对污染物的运移具有显著的影响。在常见水力梯度条件下,当渗透系数较小时,污染物的运移以弥散为主,污染晕接近圆形,污染晕半径较小。当渗透系数增大达到1×10^-4m/s,流速较大,对流在运移过程中居于主要地位,污染晕显著扩大。为了使填埋场的纳污量最大化,提高填埋场的使用寿命,运用多种边坡稳定分析方法,对特定填埋场的边坡坡比进行了优化计算。计算结果表明,在满足稳定性要求的条件下,当采用坡比在1:4～1:5左右时,填埋场的容量可以达到最大。更多还原

【Abstract】 Landfill is a kind of suitable sludge disposal method for China. In the methods of laboratory tests, theoretical analysis and numerical simulations, researches were conducted on environment and engineering properties of sludge. Then, fly ash, silty clay and lime were utilized to improved the landfill properties of sludge.Different kinds of sludge disposal method at present were compared firstly. Then both advantages and disadvantages of these methods were summarized. In order to solve the technical problems in landfill of sludge for China, a method, in which the sludge will be disposed by monofill after its landfill properties was improved, was put forward in this paper.Landfill properties improved by the adding of the consolidation materials. Significant increases in sludge strength and permeability was achieved to match suitability for monofill. The adding of lime can improve the volume stability and permeability of solidified sludge. Based on orthogonal experiment, the solidifying effectiveness of silty clay was found to be more notable than fly ash. This can be resulted from the special environment of sludge in which the activities of fly ash was not excited.Freeze-drying technology and scanning electron microscope were utilized to study the microstructure of solidified sludge. It was found density of sludge was improved after solidification. The hydration effect of solidifying materials and sludge can be the reason of improvement in strength and complication in microstructure. Perimeter and area of soil grain can be effective parameters to describe the microsturcture of soil.The column fill with lime and sludge performs the highest permeability, the largest mount of leachate, the highest PH and the highest COD because of the adding of lime. Lime performed a double influence on heavy metals in sludge. It can cause the instability of copper ion in sludge but make the zinc ion more stable. The influence of silty clay and fly ash was not significant.Transport of contaminant from sludge was studied with numerical simulation in varied geological conditions. It was revealed that adsorption function, permeability and hydraulic gradient play the key role in the transport of contaminant. For normal hydraulic gradient and low permeability stratum, dispersion controls the transport. While the permeability was improved to 1×10^-4m/s, convection controls the transport and the contaminated area was expanded significantly.Life expectancy is an important design parameter of landfill. To improve the capacity and life expectancy of landfill, the slope ratio of landfill was optimized with different computation methods of slope stability. It was revealed that, when the slope ratio of 1:4～1:5 was adopted, the capacities of landfill can reach the maximum value as the stability of slope can be satisfied at the same time.更多还原