VOLATILE ORGANIC COMPOUND EMISSIONS MONITORING DURING REMEDIATION AT A SUPERFUND SITE

A remediation team conducted a six-month pilot project on a lagoon (impoundment) in a 400-plus acre Superfund site. The lagoon contained thousands of gallons of liquid and sludge, with high concentrations of volatile organic compounds (VOCs), semi-VOCs, and hydrogen sulfide (H₂S).  

The plan was to superheat the liquid in place, 24/7, in a closed system. Then, the remediation team would convey the resulting gas to a nearby thermal oxidizer for complete destruction. The team planned to conduct the pilot project near a number of sensitive sites, such as a public park, an active rail line, several commercial buildings, residential houses, and an interstate highway.  

The Environmental Protection Agency (EPA) was concerned that the pilot project activities would cause the release of VOCs—benzene in particular—and H₂S. The EPA wanted an effective and efficient method to measure potential emissions, at the parts-per-billion (ppb) level. Any air monitoring program would need to include real-time measurements at many locations throughout the Superfund site. 

Triumvirate Environmental installed 10 air monitoring stations at strategic locations around the lagoon and near highly sensitive receptors. Each station comprised a Photoionization Detector (PID), an H₂S monitor, and a Greenlight™ benzene monitor. A separate air detector system monitored the exhaust gas from the thermal oxidizer for traces of total volatile organic compounds (TVOCs) and H₂S. 

Once in operation, the integrated system effectively measured fugitive VOCs, benzene, and H₂S, down to 3.0 ppb. The system live-streamed the results to project and EPA personnel, and it also sent out email and text alerts for any levels above a preset response threshold. 

Using the Greenlight™ Environmental Monitoring System, the project team integrated data from the stations with readings from three wind speed and direction sensors. The collected Greenlight™ data proved the team could safely perform the remediation project—without negative impact to the surrounding community.