Laboratory testing for evaluating performance of the residue in the environment

• Main Author: Lim, Daryl Sze Suan
• Other Authors: Fei Xunchang
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Environmental engineering; Engineering::Civil engineering
• Online Access: https://hdl.handle.net/10356/154337
• Institution: Nanyang Technological University

Municipal Solid Waste (MSW), also known as trash, is a nonhomogeneous mixture collected by the municipality or disposed of at waste disposal sites. Residential, commercial, and industrial wastes are all examples of municipal solid waste that are collected. Although the composition of MSW may vary, it is generally accepted that organic materials make up the largest component of MSW. They also sometimes consist of some metals which have to be recovered prior to pyrolysis, which is the thermal decomposition of materials at elevated temperatures in an inert atmosphere or subjected to other conversion processes. Thermal technologies dealing with MSW are referred to as waste treatment technologies. Due to land scarcity, Singapore has adopted waste incineration as the primary waste disposal method as it reduces waste volume by 90%. The mass burn Waste-To-Energy (WTE) method produces electricity for usage and ash is collected from that process. The ash collected from the incineration process, also known as Incinerator Bottom Ash (IBA), is discharged from the moving grate of MSW incinerators. These collected ash typically contain a small amount of ferrous metals in them and can be processed to remove its contaminants. Pulau Semakau being Singapore’s only landfill is expected to be fully filled up in 2035. Hence, the opportunity to prolong the lifespan of the Semakau landfill was to find a use for the IBA after it has been processed. It has been found that after pre-treatment IBA has excellent mechanical properties, with a well-graded particle size distribution. This allows the processed IBA to be able to replace road construction materials such as sand, gravel and crushed rocks as a subbase in road construction. The only downside is the presence of inorganic substances in IBA, when not pre-treated sufficiently, will potentially be harmful to the environment and human health. With the possibility of prolonging the use of the Semakau landfill and reusing the IBA into construction material, this study focuses on assessing and evaluating the leaching behaviour through tests before the material is used reliably and routinely.