Environmental assessment of four waste cooking oil valorization pathways

[Display omitted] •Environmental impact for different waste cooking oil uses is assessed.•Waste cooking oil is compared with virgin products for four applications.•An innovative waste cooking oil valorization pathway is proposed.•Waste cooking oil alternatives are usually more sustainable.•The waste cooking oil best performance is as direct burning fuel. Global waste is expected to grow substantially by 2050, therefore, defining an effective waste management strategy is a crucial topic for both industry and academia. Nowadays, food and green waste, in particular, represent a large share of the total waste production. All this considered, effectively processing and eventually reusing materials such as waste cooking oil is of paramount importance. This study investigates the potential environmental impact and the primary energy consumption for three waste cooking oil valorization pathways i.e. biodiesel, direct burning fuel, additive for recycling aged-asphalt, as well as a new application, i.e. phase change material, compared to their specific more common alternative based on a cradle-to-gate approach. The aim is to identify and recommend the most advantageous alternative in terms of environmental impact. Results showed that the waste cooking oil has a lower impact in all comparisons made, except as phase change material. The less effective performance in some cases was compensated by the waste oil entry as a burden-free resource under an attributional model. The best profile of the waste cooking oil is as direct burning fuel. However, the binder asphalt substitution is highly recommended due to the nature of the application. The major obstacles to the waste cooking oil usage are the limited stock, composition and quality variability, and the difficulty of proper collection.