The fate and behaviour of nano ZnO during waste stabilization in landfills

As a result of rapid development in nanotechnology in recent years, the number of commercially available nanotechnology products has exceeded one thousand. The extensive use of NMS in commercial consumer products and their eventual release to the environment through various pathways have recently raised concern about the potential impacts of these materials on the environment and human health. It is estimated that more than 50 % of nanometarials (NMS) used in cosmetics, health, electronic, textile and water treatment sectors, will ultimately be sent to landfills for final disposal after their useful lifes are over. It is reported in the literature that research activities have mostly focused on the ecotoxicity of NMS. However, the fate and behavior of NMs during waste stabilization in landfills, which play a crucial role in integrated waste management systems, is still unknown. In particular, little data is available on how these materials behave in an integrated waste management system under changing environmental conditions. The transport behavior of nanoparticles from the solid waste into leachate is also dependent on the properties of landfill leachate and the environmental factors. Therefore, it is important to investigate the fate of nanoparticles in landfills to understand and control the environmental impacts that may occur in advance. Especially, their potential impacts on waste stabilization, landfill gas production, geomembranes and the risk for the groundwater and surface water contamination are still unknown. Therefore, the main objective of this study is to provide greatly needed fundamental information and insight into the fate and impact of nano ZnO during waste stabilization in landfills. For this purpose, 70 liter lab-scale simulated conventional landfill and bioreactor landfill lysimeters were loaded with fresh municipal solid waste obtained from a real landfill site and the reactors were uniformly mixed with pre-known amounts of nano ZnO. Samples were regularly taken from leachate and gas phases, to assess the impact of nano ZnO on different phases of waste stabilization. Daily and cumulative biogas and methane production values of each reactor were monitored to determine the impact of nano ZnO on gas production.