Evaluation of flue gas emission factor and toxicity of the PM-bounded PAH from lab-scale waste combustion.

Atmospheric particulate matter (PM) has a significant threat not only to human health but also to our environment. In Hungary, 54% of PM10 comes from residential combustion, which also includes the practice of household waste burning. Therefore, this work aims to investigate the quality of combustion through the flue gas concentrations (CO, CO2, O2) and to identify and evaluate the negative impacts of PM and PAHs generated during controlled lab-scale combustion of different mixed wastes (cardboard and glossy paper, polypropylene and polyethylene terephthalate, polyester and cotton). Mixed wastes were burnt in a lab-scale tubular furnace at different temperatures with 180 dm3/h air flow rate. Chemical analyses were coupled with ecotoxicological tests using the bioluminescent bacterium Vibrio fischeri. Ecotoxicity was expressed as toxic unit (TU) values, toxic equivalent factors (TEF) were also presented. During the combustion same amount of O2 enters the reaction, but a different amount CO2 is generated due to the C content of the sample. The waste with highest C-content related to the highest CO2 emission. Increasing the combustion temperature produces more PM-bound PAHs, which remains the same composition in the case of plastic and textile groups. The TU of solid contaminants decreases with increasing combustion temperature and increases with the minerals which are left behind in the water from the solid contaminants.

Exploring the Potential to Repurpose Flexible Moulded Polyurethane Foams as Acoustic Insulators.

Polyurethane flexible foams are widely used for a variety of applications to improve comfort and durability. Their long-term frequent use inevitably leads to the generation of waste that needs to be treated. The recycling and reuse of polyurethane waste are essential to achieve an environmentally friendly economy. The present study investigates the potential to reuse and repurpose flexible polyurethane foam from automotive seat cushion waste materials. Flexible foams were prepared with different hardnesses using isocyanate-polyol ratios between 0.8 and 1.2 NCO-index. Dry heat aging tests were performed to mimic the long-term usage of the materials. The decrease in compressive strength was compared with the change in acoustic damping properties before and after the aging tests using an acoustic tube, and the change in foam cell structures was also analyzed by micro-CT. On the basis of the results obtained, although the foam systems are no longer suitable to be used as seat cushions due to aging, they can still be used as sound insulation materials within a given frequency range, as their sound absorption capacity is suitable for such purpose.