Public tours are held by appointment only. Please call 503-393-0890 to set up an appointment.
The keystone of Marion County’s solid waste disposal system is the Waste-to-Energy Facility (WTEF) located in Brooks just off Interstate 5. The plant is privately owned and operated by Covanta Marion, Inc.
The facility processes on average 550 tons of garbage each day and provides the 325,000 citizens of Marion County with a reliable and environmentally safe means of garbage disposal.
Each day, about 130 loaded refuse trucks arrive at the facility. Once there, they are weighed by truck scales. The truck then proceeds to the tipping floor where the garbage is dumped into a 34-foot deep pit. Nearly 3,000 tons of refuse can be held in the pit at a time. An overhead crane mixes the garbage in the pit and lifts it into one of the two hoppers that feed the two boilers.
The trash is burned at temperatures reaching 2,000 degrees Fahrenheit. This head boils water, generating steam which in turn drives turbines which generate electrical power. By burning our trash, the facility generates approximately 13 Megawatts of electricity annually, enough to provide power for a city the size of Woodburn every year.
The WTEF processes about 90% of the County’s garbage. The other 10% consists of construction and demolition wastes, food processing waste, and other miscellaneous non-burnable materials. These materials are placed in the County’s existing demolition landfill in Salem or is hauled to an out-of-county landfill.
As would be expected, the facility performs extensive air and ash quality monitoring in compliance with the Oregon Department of Environmental Quality and the U.S. Environmental Protection Agency. To date, it’s environmental compliance record has been exceptional.
The WTEF not only converts garbage typically destined for a landfill into useful energy, it also provides an additional recycling service. Ferrous and non-ferrous metals which were not previously separated from the waste and which are processed through the combustion chambers are picked out of the ash with large magnets and an eddy current machine. This metal is cleaned and taken to markets for recycling. Last year, about 3,356 tons of metal were recycled by the Waste-to-Energy Facility.
During the incineration process, ash is generated in two ways. First, as material is combusted in the boiler, a residue is generated on the bottom of the boiler, called “bottom ash”. After combustion, this material is quenched with water in order to reduce its temperature. This ash is then placed on a conveyor. As the waste is burned, many fine particles are carried away with the hot air stream which rises from the boiler. As mentioned above, this heat is used to boil water which generates steam used to drive the turbines. The particles are collected when the air is passed through the fabric baghouse filters prior to being discharged. This material is called “fly ash”. This ash is shaken loose from the baghouse filters and is placed on the same conveyor which carries the bottom ash, resulting in a mixture of the two.
The ash on the conveyor is then passed under a magnetic separator in order to remove the ferrous metals present in the ash. An eddy current machine is used to separate non-ferrous metals. The metals recovered are recycled. The ash is then deposited in an enclosed storage structure. From there, it is loaded into twin trailer trucks for transport to the North Marion County Disposal Facility ash monofill. The material is tipped from the truck at a designated location, and the ash is reprocessed to screen out additional ferrous and non-ferrous metals which were not removed at the WTEF. Last year 1,316 tons of metal were recycled. Most of the ash is then loaded into trucks which transport it to the Coffin-Butte Landfill north of Corvallis where it is used as daily cover in leu of soil. The ash is covered with a tarp during transport. Once a portion of the ash monofill has been brought to its final design elevation, final cover is placed over that section. This cover typically includes a flexible membrane liner along with a layer of seeded topsoil.