Department of Environmental Science and Engineering, Indian Institute of Technology Bombay, Mumbai, India.
Waste Manag Res. 2024 Dec;42(12):1168-1178. doi: 10.1177/0734242X231219654. Epub 2024 Jan 17.
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.
近年来，垃圾填埋场开采的概念在印度得到了广泛关注，大量的塑料废物正在被挖掘出来。当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，由于在垃圾填埋场中的降解和风化过程，塑料废物的物理化学特性会发生变化，使其难以增值。本研究调查了印度垃圾填埋场中塑料废物随年龄变化的物理化学特性，以确定潜在的增值选择。此外，还考虑了塑料废物的焚烧处理，进行了物料和能量流分析。该垃圾填埋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，这是由于印度塑料废物产生量的增加。挖掘出的塑料废物中，聚乙烯（高密度和低密度）约占 66%，且附着了大量的表面杂质。使用破碎机进行机械预处理可以有效地去除附着的杂质，聚乙烯的回收率为 50-70%，而其他类型塑料的回收率更高，为 70-90%。通过扫描电子显微镜观察到塑料废物随老化而发生的表面形貌变化。傅里叶变换红外光谱结果证实了老化塑料废物的低降解水平，这也通过检测到的高氧含量得到了证实。物料和能量流分析表明，焚烧一吨挖掘出的塑料废物可产生约 1410 千瓦时的电力。
