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首页> 外文学位 >Optimization of Leachate Recirculation Systems in Bioreactor Landfills.
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Optimization of Leachate Recirculation Systems in Bioreactor Landfills.

机译：生物反应器垃圾填埋场渗滤液再循环系统的优化。

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摘要

Several scenarios were assumed and numerical simulations were performed to study the response of horizontal trenches (HTs), vertical wells (VWs) and drainage blankets (DBs) when used as leachate recirculation systems (LRS) on moisture distribution and the pore water and gas pressures accounting for the effects of saturated and unsaturated hydraulic properties of municipal solid waste (MSW), inhomogeneity and anisotropic property of waste, LRS system geometric configurations, leachate injection rates and mode of leachate injection. Results indicated that the unsaturated hydraulic properties of MSW govern the moisture distribution in the waste when the gravity drainage exists. Further, the time required to reach steady-state will significantly differ for different sets of unsaturated hydraulic properties, though there is no considerable difference in the wetted area, wetted width and pore water pressure. Results on effects of inhomogeneity and anisotropy of waste indicated that the leachate injected will migrate in the lateral direction, which may reach the slope and endanger the stability of the slope, due to the anisotropy of MSW. Geometric configurations of different LRS depend greatly on the leachate injection rate and mode of leachate injection. Lesser the spacing of LRSs higher will be the area influenced; however, excess pore water pressures will be developed when leachate is injected continuously. Besides, injecting the leachate intermittently will result in developing the pore gas pressures due to unsaturated condition. Therefore, pore water and gas pressures are important key factors to be considered to evaluate the stability of landfill slope and the cover system.;Comparative evaluation of different LRS was then performed to examine the effectiveness of each LRS to distribute the moisture and pore water and gas pressures developed within the landfill. Results indicated that the DB when used as LRS will be more effective than the HT and VW to influence more area in the landfill when an equal amount of leachate is injected in all the three LRSs. Further, the pore pressures in case of DB was observed to be controllable than in case of HT. On the other hand, though VW did not indicate excess pore water and gas pressures, this system was not effective to produce better influence area in the landfill. Intermittent leachate injection will result pore gas pressure to dominate in case of all the three LRS considered.;Based on the system response of different LRS, a detailed parametric study by varying one design factor at a time was performed to develop design charts that can estimate the wetted width, wetted area and maximum pore water pressure build up in the landfill due to leachate injected until steady-state condition, considering the waste as inhomogeneous and anisotropic. The design charts developed are non dimensional and simple to use in the field to estimate the spacing of different LRS, and the volume of leachate to be injected based on the hydraulic properties of MSW and the location of LRS with respect to the LCRS.;Effect of spatial variation of hydraulic conductivity of MSW within the landfill to account for highly heterogeneous waste was evaluated on Orchard Hills Landfill, Davis Junction, Illinois, USA. Based on the literature review, large coefficient of variation (CoV) of saturated hydraulic conductivity was selected and the Monte Carlo simulations were performed to evaluate the wetted area, pore water pressure developed and the outflow collected at LCRS. Reliability analysis was then performed to examine the effective of the bioreactor landfill to serve as an excellent performing landfill. Reliability analysis indicated that the existing LRS and the leachate injection rates practiced in the field are not proficient. Therefore, it is highly recommended that that % area of influence of MSW should not be less than 60% and the ratio of PP/Total stress of 0.52 can be considered as safe. Therefore, it is suggested that landfill designers should install different configuration for the LRS and higher leachate injection rates to increase the wetted area. This will improve the biodegradation process of MSW and the overall efficiency of the functioning of the landfill and the increased outflow rate of leachate. (Abstract shortened by UMI.).
机译：假设了几种情况，并进行了数值模拟，以研究水平槽（HTs），垂直井（VWs）和排水层（DBs）在用作渗滤液再循环系统（LRS）时对水分分布以及孔隙水和气压的响应考虑到城市固体废物（MSW）的饱和和不饱和水力特性，废物的不均匀性和各向异性，LRS系统的几何结构，渗滤液注入速率和渗滤液注入方式的影响。结果表明，存在重力排水时，城市固体废弃物的不饱和水力特性决定了废物中水分的分布。此外，对于不同组的不饱和水力特性，达到稳态所需的时间将显着不同，尽管湿润面积，湿润宽度和孔隙水压力没有显着差异。对废物的非均质性和各向异性的影响的结果表明，由于城市固体废弃物的各向异性，注入的渗滤液将沿横向迁移，可能会到达斜坡并危及斜坡的稳定性。不同LRS的几何构型在很大程度上取决于渗滤液的注入速率和渗滤液的注入方式。 LRS的间距越小，受影响的区域就越大；但是，连续注入渗滤液时，会产生过多的孔隙水压力。此外，间歇注入渗滤液会由于不饱和条件而导致孔隙气体压力升高。因此，孔隙水和气压是评估垃圾填埋场边坡和覆盖系统稳定性的重要关键因素。然后，对不同的LRS进行了比较评估，以检验每种LRS分配水分和孔隙水的有效性，以及垃圾填埋场内产生的气体压力。结果表明，当在所有三个LRS中注入等量的渗滤液时，DB用作LRS将比HT和VW更有效地影响垃圾填埋场中的更多区域。此外，观察到与HT相比，在DB的情况下的孔隙压力是可控的。另一方面，尽管大众汽车公司并未表明孔隙水和气压过高，但该系统无法有效地在垃圾填埋场中产生更好的影响区域。在考虑所有三个LRS的情况下，间歇性注入渗滤液将导致孔隙气体压力占主导地位。基于不同LRS的系统响应，通过一次改变一个设计系数进行详细的参数研究，以开发出可估算的设计图。考虑到废物是不均匀和各向异性的，由于渗滤液注入到稳态之前，在垃圾填埋场中会形成湿宽度，湿面积和最大孔隙水压力。所开发的设计图是无量纲的，并且易于在现场使用，以根据MSW的水力特性和LRS相对于LCRS的位置来估计不同LRS的间距以及要注入的渗滤液量。在美国伊利诺伊州戴维斯交界处的果园山垃圾填埋场评估了垃圾填埋场内城市固体废弃物水力传导率的空间变化，以解释高度异质的废物。基于文献综述，选择了饱和导水率的大变异系数（CoV），并进行了蒙特卡洛模拟，以评估湿润面积，孔隙水压力的产生以及LCRS收集的流出物。然后进行可靠性分析，以检查生物反应堆填埋场作为出色的填埋场的有效性。可靠性分析表明，该领域中现有的LRS和渗滤液注入率不高。因此，强烈建议MSW的影响面积百分比不小于60％，并且PP /总应力之比为0.52可认为是安全的。因此，建议垃圾填埋场设计者应为LRS安装不同的配置，并增加渗滤液的注入速度以增加湿润面积。这将改善城市生活垃圾的生物降解过程，并改善垃圾填埋场的整体运行效率，并提高渗滤液的流出速度。 （摘要由UMI缩短。）。

著录项

  • 作者

    Kulkarni, Hanumanth S.;

  • 作者单位

    University of Illinois at Chicago.;

  • 授予单位 University of Illinois at Chicago.;
  • 学科 Engineering Civil.
  • 学位 Ph.D.
  • 年度 2012
  • 页码 643 p.
  • 总页数 643
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 遥感技术;
  • 关键词

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