Stack Emission from the ECS
The Environmental Control Enclosure (ECE) had an Emission Control System (ECS) that worked in conjunction with the enclosure to mitigate environmental impacts and maintain a safe environment for personnel undertaking remediation activities inside.
The emission control system filtered the air that was extracted from the environmental control enclosure. The air passed through a series of particulate and granular-activated carbon filters which removed contaminants from the air.
The activated carbon filters were configured with the extracted air first passing through a lead filter followed by a lag filter. The air was continuously monitored between the lead and lag beds to indicate when the activated carbon filters needed to be changed. The detection of contaminants between the lead and lag beds indicated that the lead bed was becoming saturated and the lead activated carbon filter was then replaced. This system ensured that there was no breakthrough of contamination. As an additional precaution, contaminant levels were also monitored following the lag beds.
All particulate filters were replaced when the in-built monitors indicate that replacement was required. This was well before the point when the efficiency of the system’s operation would become restricted. After the filtering process, the air was released through a stack.
To maintain sufficient air circulation within the environmental control enclosure, air extracted from inside the enclosure was replaced with ventilated fresh air.
The emission control system was fully tested when it was commissioned. When full scale remediation excavations and associated activities commenced, the emission control system began operating continuously.
Environmental monitoring was conducted during the remediation to confirm the effectiveness of the environmental controls and to protect the health of workers and community members, and the surrounding environment. Levels of dust, including PM10, volatile organic compounds and noise were continuously monitored at the residential boundary closest to the emission control system.