State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, 1239 Siping Road, Shanghai 200092, China; Shenzhen Academy of Environmental Sciences, 50 Honggui Road, Shenzhen 518001, China.
Department of Environmental Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
Waste Manag. 2015 Dec;46:362-72. doi: 10.1016/j.wasman.2015.09.016. Epub 2015 Sep 28.
The quantity of leachate is crucial when assessing pollution emanating from municipal landfills. In most cases, existing leachate quantification measures only take into account one source - precipitation, which resulted in serious underestimation in China due to its waste properties: high moisture contents. To overcome this problem, a new estimation method was established considering two sources: (1) precipitation infiltrated throughout waste layers, which was simulated with the HELP model, (2) water squeezed out of the waste itself, which was theoretically calculated using actual data of Chinese waste. The two sources depended on climate conditions and waste characteristics, respectively, which both varied in different regions. In this study, 31 Chinese cities were investigated and classified into three geographic regions according to landfill leachate generation performance: northwestern China (China-NW) with semi-arid and temperate climate and waste moisture content of about 46.0%, northern China (China-N) with semi-humid and temperate climate and waste moisture content of about 58.2%, and southern China (China-S) with humid and sub-tropical/tropical climate and waste moisture content of about 58.2%. In China-NW, accumulated leachate amounts were very low and mainly the result of waste degradation, implying on-site spraying/irrigation or recirculation may be an economic approach to treatment. In China-N, water squeezed out of waste by compaction totaled 22-45% of overall leachate amounts in the first 40 years, so decreasing the initial moisture content of waste arriving at landfills could reduce leachate generation. In China-S, the leachate generated by infiltrated precipitation after HDPE geomembranes in top cover started failing, contributed more than 60% of the overall amounts over 100 years of landfilling. Therefore, the quality and placing of HDPE geomembranes in the top cover should be controlled strictly for the purpose of mitigation leachate generation.
评估城市垃圾填埋场产生的污染时，渗滤液的数量至关重要。在大多数情况下，现有的渗滤液量化措施仅考虑了一个来源——降水，由于中国垃圾的高含水量特性，这导致了严重的低估。为了克服这个问题，建立了一种新的估计方法，考虑了两个来源：（1）渗透过废物层的降水，这是通过 HELP 模型模拟的；（2）从废物本身挤出的水，这是根据中国废物的实际数据理论计算的。这两个来源分别取决于气候条件和废物特性，而这些因素在不同地区都有所不同。在这项研究中，调查了 31 个中国城市，并根据垃圾填埋场渗滤液产生性能将其分为三个地理区域：中国西北部（中国-NW），气候半干旱温和，废物含水量约为 46.0%；中国北部（中国-N），气候半湿润温和，废物含水量约为 58.2%；中国南部（中国-S），气候湿润，亚热带/热带气候，废物含水量约为 58.2%。在中国-NW，积累的渗滤液量非常低，主要是废物降解的结果，这意味着现场喷洒/灌溉或再循环可能是一种经济的处理方法。在中国-N，压实过程中从废物中挤出的水量占前 40 年总渗滤液量的 22-45%，因此降低进入垃圾填埋场的废物初始含水量可以减少渗滤液的产生。在中国-S，覆盖顶部 HDPE 土工膜失效后，渗透降水产生的渗滤液在 100 年的填埋过程中，超过了总渗滤液量的 60%。因此，为了减少渗滤液的产生，应严格控制覆盖顶部 HDPE 土工膜的质量和铺设位置。
