Mechanical biological treatment of municipal solid waste: Energy efficiency, environmental impact and economic feasibility analysis

Municipal solid waste (MSW) is treated mainly via landfill and incineration in most countries. As the effectiveness of source-point waste classification always cannot be guaranteed especially in developing countries, the introduction of mechanical-biological treatment (MBT) systems is a possible solution, for MBT can separate the biodegradable fraction and recover recyclables from mixed waste streams. Using life cycle assessment, scenario analysis and other methods, the energy, environmental and economic performance of MBT and other mainstream MSW treatment technologies are analyzed and compared. The results showed that raw MSW landfill was the worst management option. Incineration had higher energy efficiency (20.5% energy recovery), but the large amounts of chemicals consumption for fly ash and exhaust treatment were also issues leading to relatively higher life cycle environmental impacts. MBT had the highest energy efficiency when connected with biogas purification systems (38.5% energy recovery), and could significantly avoid pollution than the other two technologies. Moreover, MBT was well-adapted to changing MSW composition, making it a promising supplementary to MSW source separation. However, MBT had weak economic performance and required an economic support policy. Our findings show that product revenue needs to be increased, and infrastructure sharing between MSW treatment facilities should also be encouraged.