Rockland Solid Waste Facilities Manager Dave St. Laurent beside the Solar Spark Vent Flare that burns off <br /><br /><!-- 1upcrlf2 -->landfill gases - Photo by Glenn Billington
Rockland Solid Waste Facilities Manager Dave St. Laurent beside the Solar Spark Vent Flare that burns off

landfill gases - Photo by Glenn Billington
A flare that burns off trapped methane and other gases in the pit at the Rockland landfill has already noticeably reduced noxious odors in the neighborhood, according to the Maine Department of Environmental Protection, while reducing odor management costs.

A piping system was installed in the old Rockland landfill quarry in 2010 to manage odors. Dave St. Laurent, the solid waste facility manager for Rockland, thought more could be done.

"After a greenhouse gas study in 2011 and some research, I found that we could install a passive flare system, a system without blowers . . . that would decrease the odors by flaring off some of the trapped landfill gases," said St. Laurent.

St. Laurent had the landfill gases analyzed for content, then put the proposal for a solar-ignited flare in front of the Maine DEP, which approved it.

The passive flare, which was installed October 19, has been in constant operation since it was ignited. It is fueled by landfill gas and is ignited by a spark plug that is powered by a 6-volt battery, charged by a small solar panel.

Odor management of hydrogen sulfide, which produces the noxious rotten-egg smell, even at extremely low concentrations, is not the only benefit of the flare. Methane, the largest component of the trapped landfill gasses, packs a big greenhouse gas impact. Flaring off methane gas reduces that impact.

St. Laurent said the volume of gas is not high enough to make it economical to use the flare for heat, which would require scrubbing the gas and installing systems to make it functional.

A fail-safe system to manage the landfill fluids from escaping into the stormwater system during a storm and a system to finely calibrate the hydrogen peroxide treatment of the noxious hydrogen sulfide were also installed last month.