A Smart-Contract-Aided Plastic Credit Scheme.

Researchers estimate that more than 8.3 billion tonnes of plastic have been produced since the early 1950s; however, only 9% of all plastic waste ever produced has been recycled. In this article, we propose a plastic credit driven system consisting of a recyclability index (RI) and plastic credit to impel plastic recycling and increase the quality of recyclable plastics through a market self-regulation mechanism. The RI is designed to evaluate the recyclability value of different plastic products based on their material compositions. The plastic credit, defined by the quantitative relation between the RI and product information, can be issued or traded by system stakeholders. Instead of setting rigid industry standards to regulate plastic quality, we construct a governance community among industry participants using blockchain-enabled smart contracts to self-regulate and monitor plastic production and trading. The proposed system is constructed on a consortium blockchain and a public blockchain to negotiate the RI, issue credits, and trade credits using smart contracts. Through the overall system performance analysis, the experimental results demonstrate that the designed plastic credit system can promote a demand shift toward plastic products with higher plastic recyclability and achieve a lightweight operation for resource requirements and system maintenance.