Plastic Contamination in Source Separated Household Bio-Wastes Collected in the Swiss Region of Lausanne

Municipal and commercial biological waste represent significant sources of biogas and organic fertilizer in Western societies, contingent upon responsible collection and treatment practices. Non-permitted objects (NPO) entering the waste stream are deemed contaminants and exert adverse effects. Particularly, plastics present formidable challenges in industrial waste recovery facilities, diminishing their energy and fertilizer utility. This study focused on analyzing the composition of a bio- waste collection truck from an urban area in Western Switzerland. Manual separation revealed: 37.5% of the total load was encased in plastic bags: of which 33.8% were compostable, while 66.2% non-compostable plastic materials. 1.5% of the total weight of the truck load was considered non-permitted: 8% of it found in the non-compostable fraction, 1% inside the compostable fraction. A subsequent household bio-waste (HBW) bag sampling from five different communes revealed that 89.3% of households employing non-compostable bags also dispose other NPO within, compared to 34.6% of the compostable bag users. The results indicate that currently applied practices for the source-separation of the valorizable fraction of HBW needs to be improved to lift its full potential – consequently, the authors compiled elsewhere applied approached to deal and improve this delicate but relevant topic of developed societies.