- Allen County Landfill
Allen County, Kansas, owns and operates a Subtitle D landfill that serves as a regional solid waste disposal facility for its residents as well as a surrounding 12-county area. The Allen County Commission and staff have recently completed a project at the landfill that saves taxpayers thousands of dollars, increases worker productivity, improves overall air quality and lessens the county's use of foreign sources of energy.
The commission wanted to explore options for heating a 6,000-square-foot public works equipment storage and maintenance building in the winter months. Keeping the equipment warm in the winter would eliminate cold weather startup stresses while at the same time making the building's users more comfortable to perform equipment maintenance.
The commission contracted with Burns & McDonnell for the project. The ingenuity and foresight of the commission combined with Burns & McDonnell expertise to arrive at a unique solution.
The adjacent Allen County Landfill produces methane gas, which is collected and conveyed to a gas flare. The methane content of the gas is approximately 50 percent and is suitable for a heating beneficial reuse.
There are many ways to provide heating with landfill gas. Burns & McDonnell and the county commissioners evaluated several options and determined infrared heaters would be the most efficient and economical. The heating demand load for the building, adjusted for infrared heaters, was estimated to be 500,000-600,000 BTU per hour.
In order to meet the estimated heating demand, Burns & McDonnell recommended the installation of eight, 80,000 BTU burners to be installed in two capital "H" patterns, with the H axis parallel to the length of the building. After evaluating several options, the commission selected D&R Plumbing & Electric Inc. as the general contractor and Lee Craig & Associates Inc. as the supplier of the infrared heaters. The heaters used were Reflect-0-Ray EDS 3.5, by Combustion Research Corp.
Worker Benefits: Allen County Landfill maintenance employees can now work in the comfort of a warm building during the frigid winter months, which improves employee satisfaction and productivity. In fact, the first winter, employees could be heard over two-way radios arguing who would get to use the equipment stored in the building.
Taxpayer Benefits: Infrared heating was a less expensive method than several alternatives studied. For example, heating the building using a landfill gas boiler, a popular method, would have cost $70,000. Hydronic heating using a landfill gas boiler would have cost the county $148,000. With county budgets constantly under pressure, finding a low-cost alternative to heating an important county building allowed the Allen County Commission to spend its savings on vital county programs. It should also be noted that of all the alternatives considered, infrared heating offered the quickest payback, about four years, resulting in another benefit to the taxpayers of Allen County.
Equipment Benefits: In addition to eliminating heavy machinery startup stresses, the heat also allows faster and easier startup of the Alternative Daily Cover Hydroseeder applicator. The hydroseeder mixes recycled newspaper, biodegradable tackifiers and water to provide a daily cover material for the landfill's work face. Keeping the hydroseeder warm during winter months is essential for proper operation.
Environmental Benefits: Since flared methane gas contributes to greenhouse gases, removing this amount of methane from being flared into the atmosphere is the equivalent of:
- Taking 36 cars off the road
- Planting 50 acres of forest
- Offsetting the use of 0.8 railcars of coal
- Preventing the use of 390 barrels of oil
- Heating approximately 10 homes per year
It should also be noted that using landfill gas to heat the maintenance building lessens dependence on foreign sources of oil.
The most obvious special feature of the project is it uses landfill gas as fuel to warm an entire 6,000-square-foot building. Most building heating projects in the United States use internal combustion engines and natural gas or fuel oil as fuel.
The gas is captured as it emerges from the landfill and is piped to the maintenance building, where it is filtered, dried and converted for use in the application. This is only the second successful application of infrared heating of landfill gas in the country. One reason it is being used is because infrared heaters are among the most efficient means for heating heavy equipment. Infrared heaters heat people and objects directly, as opposed to forced air systems, which heat the air. The energy emitted is absorbed by surfaces that warm up, which in turn release heat into the air.
This project is the first beneficial reuse of landfill gas at the landfill. Given that the emissions of methane have not yet reached their peak, it is anticipated there will be other beneficial use projects in the future.
The beneficial use has been enhanced by the method of remediation chosen for the adjacent landfill. The Allen County Commission approved a plan designed by Burns & McDonnell to close a pre-Subtitle D, 15-acre section of the landfill in 2003. The landfill cap was designed using Subtitle D standards, which reduce surface emissions, allowing more gas to be captured and put to beneficial use. The Allen County Commission, public works director and landfill superintendent demonstrated exceptional foresight in using this type of design, since they were not required to.
Their extra efforts have resulted in a solution that benefits Allen County taxpayers and will pay dividends in the form of other beneficial use projects for years to come.