Solid Waste Valorization: Concepts, Principles, Valorization Techniques, and Integrated Waste Management

Resumo

Waste mismanagement challenges sustainability and harms the environment and public health – it contributes to water, soil, and air pollution. In this context, the waste valorization perspective views undesired streams as potential resources for protecting natural resources, generating wealth, preventing depletion, and reducing the negative externalities associated with improper disposal. This review introduces the main techniques for valorizing a broad spectrum of wastes, including recycling, bioconversion (e.g., composting and anaerobic digestion), and thermochemical methods (e.g., pyrolysis and gasification). The integration of waste valorization techniques is briefly discussed. The implementation of the waste valorization technique primarily depends on the waste characteristics and the process's technical, economic, and operational feasibility. The integration of multiple valorization techniques will not always boost resource recovery and energy efficiency. Besides,  there is no one-size-fits-all management strategy, and the best option should be assessed on a case-by-case basis. Lack of infrastructure, incentives, or a legal framework to support recovery methods can hamper the full promotion of waste valorization and resource utilization, especially in developing economies. Technological development in the waste sector and digital transformation are still required to prompt the recovery of resources from waste streams.