Effect of Physical Presence of Waste Plastics in the Degradation of Municipal Solid Waste in Landfill

Abstract

Due to the rapid growth of population, urbanization and economic development, the generation of municipal solid waste (MSW) is increasing. Among all the waste materials in MSW, raw vegetable waste materials (RVW) are biodegradable in nature, and waste plastics (WPs) are non-biodegradable and impermeable in physical character. Previously, investigations are focused on the degradation of biodegradable materials without any physical presence of WP. But some of the present literatures reveal that WP need not to be separated from MSW as done in conventional technique before dumping in the landfill, rather mixing them uniformly with the other biodegradable waste materials and investigating the net effect on the biodegradation process of biodegradable materials may it be physical. The presence of waste plastics in the MSW beds changes the physical structure of the bed with more void pockets to hold a higher amount of leachate in the bed with higher retention time. Under these circumstances, the higher rate of degradation is inevitable since the degrading materials are constantly in contact with higher moisture leading to increasing in degradations. The present work, therefore, focuses on the studies of change of physical and structural characteristics of the MSW bed both in absence and presence of WP in different proportions within the specified optimum limit and at the same time improving the biogas generation. To measure the leachate hold-up and the compressibility of MSW bed, five small MSW beds were prepared with a certain amount of RVW and WP with an increasing amount such as 0, 5, 10, 15 and 20%, respectively. It was observed that the voidage and compressibility will be increasing with the increasing amount of WP. At the same time, percentage retention of leachate inside the waste bed was increased and may be attained the maximum with the range of 10–15%, which leads to the maximum production of biogas.