When fugitive methane gas was detected close to a multi-unit apartment complex, the owner needed environmental consulting services to investigate an orphan natural gas well adjacent to the building. The well was previously discovered and plugged during construction of the apartment complex 12 years prior. However, during a routine service line inspection, natural gas was detected in the area adjacent to the vault containing the natural gas well. The fugitive methane was due to multiple malfunctions, including a leaking water well. The owner evacuated the building as a precautionary measure.

They then contracted with RETTEW to evaluate site conditions and perform emergency repairs within 24 hours. These repairs included installing a sump pump and a blower unit to actively draw and vent methane from the vault. Subsequent investigations included aquifer characterizations, isotopic methane sampling, pilot testing, feasibility analysis, and design and construction of remedial options. RETTEW replaced the existing plugged water well and vault with a dual-phase methane recovery system and an active horizontal collector to protect the building by controlling the migration of the methane venting near the building. RETTEW’s efforts, in conjunction with numerous safeguards put in place by the owner, should allow for safe reoccupancy of the building.