This paper presents a secure and scalable architecture that integrates Internet of Things (IoT), blockchain, and Data Lake technologies to improve traceability in waste management systems. The proposed system combines the MQTT protocol for efficient communication between resource-constrained IoT devices and a blockchain-based mechanism to ensure the immutability, verifiability, and authenticity of the collected data. A practical use case is demonstrated involving waste container monitoring, where IoT sensors transmit environmental and geolocation data. These data are stored in a Data Lake and cryptographically signed using Merkle trees before being anchored in a blockchain through smart contracts. The experimental results validate the feasibility of the approach and highlight its benefits in terms of transparency, auditability, and operational efficiency.
