PRINCE FREDERICK, Md.—The Calvert County Department of Public Works recently completed a landfill gas collection and control project at the former Barstow Landfill that is collecting and flaring methane to safeguard the retired site.
The $600,000 project, funded from the county Capital Improvement Plan and completed by Chesapeake Utilities and Construction of Lusby, went into operation in May 2013. A series of gas wells, flaring systems and electronic monitoring devices control the migration of gas beyond the landfill boundary and burn off methane to meet regulatory limits. The Maryland Department of the Environment requires landfills in the state to keep the concentration of methane at no more than 5 percent by volume at a facility’s property boundary.
Methane is produced when bacteria decompose organic materials buried in the landfill, such as yard waste, food waste and paper. Landfills typically produce gas that is about 50 percent methane and 50 percent carbon dioxide with trace ingredients including moisture and hydrogen sulfide, which has a noxious odor. The collection system greatly reduces the release of methane and carbon dioxide – both considered greenhouse gases – and flaring largely eliminates odors.
The 70-acre Barstow Landfill has been inactive since 1993. It was capped with a flexible membrane and a 2-inch-thick soil cover system in 1998. To exhaust the landfill gases, passive vents and gas wells were installed. Gas emissions remained within regulatory limits but methane concentrations were high near the southeast boundaries of the landfill. The new collection and control project has significantly reduced those emissions which are now well within the regulatory limits.
Landfills of Barstow’s size can produce gas emissions for 10 years or more, starting slowly, building as the contents decompose over time, then tapering off as decomposition diminishes. At its peak, Barstow produced gas at a rate of nearly 230 cubic feet per minute.
For more information, call the Calvert County Department of Public Works, Division of Solid Waste, at 410-326-0210 or visit the Calvert County website at http://www.co.cal.md.us.
Source: Calvert Co. Government