In recent years, the concept of landfill mining has gained a lot of traction in India, and tonnes of plastic waste is being excavated. The present shift towards a circular economy necessitates to explore the use of excavated plastic waste as a source of valuable materials and energy. However, the physicochemical characteristics of plastic waste change due to the degradation and weathering process in landfills, making its valorization difficult. The current study investigates the change in physicochemical characteristics of plastic waste with age from an Indian dumpsite to identify the potential valorization options. In addition, a material and energy flow analysis was performed considering incineration treatment of plastic waste. The plastic waste ranged between 3.6 and 21% in the dumpsite and has almost doubled in recent decades, owing to the increase in plastic waste generation in India. Polyethylene (high- and low-density) accounted for approximately 66% of the excavated plastic waste and had a lot of adhered surface impurities. Mechanical pre-treatment using a shredder was effective in the removal of the adhered impurities with a recovery rate of 50−70% for polyethylene and a higher recovery of 70−90% for other types of plastic. Changes in the surface morphology of plastic waste with aging were observed through Scanning Electron Microscopy. The Fourier Transform Infrared Spectroscopy results confirmed low degradation levels for aged plastic waste, which is also confirmed through the high level of oxygen detected. The material and energy flow analysis revealed that incinerating one tonne of excavated plastic waste could produce approximately 1410 kWh of electricity.

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印度垃圾场挖掘出的塑料废物的特征：调查降解程度和资源回收潜力

近年来，垃圾填埋场采矿的概念在印度受到广泛关注，数吨塑料垃圾正在被挖掘出来。目前向循环经济的转变需要探索利用挖掘出的塑料废物作为有价值的材料和能源的来源。然而，由于垃圾填埋场的降解和风化过程，塑料废物的物理化学特性发生变化，使其增值变得困难。目前的研究调查了印度垃圾场的塑料废物的物理化学特性随时间的变化，以确定潜在的增值方案。此外，还考虑了塑料废物的焚烧处理，进行了材料和能量流分析。由于印度塑料废物产生量的增加，垃圾场中的塑料废物含量在 3.6% 至 21% 之间，近几十年来几乎翻了一番。聚乙烯（高密度和低密度）约占挖掘出的塑料废物的 66%，并且具有大量粘附的表面杂质。使用破碎机进行机械预处理可有效去除粘附的杂质，聚乙烯的回收率为 50−70%，其他类型塑料的回收率为 70−90%。通过扫描电子显微镜观察塑料废物表面形态随老化的变化。傅里叶变换红外光谱结果证实老化塑料废物的降解水平较低，检测到的高水平氧气也证实了这一点。物质和能量流分析显示，焚烧一吨挖掘出的塑料废物可产生约 1410 千瓦时的电力。