A multi-sensor IoT framework for real-time detection and prevention of sewage gas explosions in domestic and occupational sanitation systems

Abstract

Introduction: Methane and toxic gases build up in sewer pipes and septic tanks and are extremely dangerous in their ability to cause explosions and poisoning to workers in the confined sewer. The traditional monitoring controls, like infection ventilation and human checking, cannot be used to offer real-time protection. Methods: In this work, the authors show an Internet of Things (IoT)-enabled cyber-physical system of real-time gas detection and automated mitigation. The system combines the MQ-4 (methane), MQ-135 (CO2 /NH 3/VOCs), and MQ-136 (H2S) sensors and place on the ESP32 microcontroller. A moving average-based compensation method is used to stabilize a sensor in contaminated conditions with minimum recalibration requirements. Alerts and ventilation are activated when methane reaches over 25% of the Lower Explosive Limit (LEL) using MQTT, in accordance with OSHA and NFPA safety requirements. Results: Testing with 250 cases indicated that the system is reliably able to detect hazards, alert, and mitigate without failure. The response time was 8.2 seconds on average, which is a safeguard against gas buildup. Multi-gas sensitivity (±18% was within a reasonable range, and the system was able to run on backup power up to 18 hours. Conclusion: The offered IoT system would turn the sanitation safety from passive observation to active protection due to real-time multi-gas detection and automated response. It offers an affordable yet scalable way of ensuring occupational safety within dangerous confined spaces.