Eco-credit system to incentivise the recycling of waste electric and electronic equipment based on a thermodynamic approach

The use of electric and electronic equipment has been increasing dramatically in the last years and entails an important amount of waste containing many valuable metals which could constitute an important source of raw materials if appropriately recycled. In this paper, an expression has been developed to value waste of electric and electronic equipment that are sent by users to an appropriate recycling plant. The user obtains in turn eco-credits, which can be later exchanged through different incentives. The eco-credit expression is based on the raw material content of the given device, assessed through an indicator called thermodynamic rarity, which rates minerals according to their scarcity in the crust and the energy required to mine and refine them. Additionally, the state of the device, lifetime and recyclability of the materials are considered in the equation. The expression has been applied as a case study to a working tablet and an LED lamp.