Managing Hazardous Confined Space Atmospheres at Sanitary Landfills

This is a review of a case study of a High Hazard Permit Required Confined Space Entry and Hazard Control Techniques. The presenter’s Industrial Site Safety Services Confined Space Rescue Unit was contracted to provide Hazard Mitigation and Confined Space Rescue Standby services to support the maintenance of environmental control equipment at a Sanitary Landfill. After multiple failures at completion, a new General Contractor was selected to replace or repair subterranean leachate collection valves in an active sanitary landfill complex. This would require a new Site Health & Safety Plan which the presenter’s firm contributed to.
12 valves were situated 15-40’ below grade located in 6 prefabricated RCP cylindrical shafts with egress from 2-15’ above grades. Each shaft presented related but unique hazard control requirements for the permitted required confined space entry. Atmospheres, specifically concentrations of Methane varied from 45-58% of the LEL in the space with pipe concentrations suitable for economic recovery as well other analytes and low oxygen levels from displacement. The project required a variety of hazard control methods to comply with permit requirements including positive dilution ventilation, pneumatic sewer plugs with bypass and flooding for atmospheric and air quality management. The presenter discusses these methods in detail. Recommended audiences are hazardous materials and technical rescue teams which may be tasked with response to emergencies at sanitary landfills as well as industrial safety partners.