Solid waste planners in King County, Washington, knew they needed a new transfer station to serve the eastern portion of the county. An initial plan sought to improve the existing transfer station but did not accommodate future growth or recycling needs. A second design looked to construct a new facility on a more visible part of the property, which caused the neighboring city of Bellevue to balk. With the purchase of adjacent property and a new construction approach, an engineering team from HDR, Omaha, Nebraska, presented a third design showcasing a larger facility on a less visible area of the property. It was this design that got approval for new construction, which was completed in September 2017.

The new Factoria Recycling and Transfer Station is a nearly 80,000-square-foot facility on a 15.6-acre site capable of handling 225,000 tons of garbage, recycling, yard waste and household hazardous waste annually. By offering an array of recycling services for major appliances, yard waste, clean wood, scrap metal, commingled recyclables and textiles, King County customers have more recycling and disposal options.

Gold standard design practices

Factoria is providing King County residents with these recycling and disposal options in an efficient and energy-saving way. The new station, designed for LEED Gold certification, is able to use 40 percent less energy than comparable facilities, reduce carbon dioxide emissions by 172.5 metric tons per year, save 1.3 million gallons of potable water annually and has diverted 95 percent of construction debris from the landfill.

LEED, which stands for Leadership in Energy and Environmental Design, is a third-party green building certification system from the Washington-based U.S. Green Building Council.

Factoria uses skylights and translucent wall panels to allow natural light into the building and is constructed from recycled building materials that are locally sourced. The facility also has been constructed to harvest rainwater.

Three underground water tanks collect rainwater for reuse in toilets and for tipping floor and equipment cleaning. The tanks are designed to reduce potable water use by 59 percent compared to traditional design.

Further, slope changes are designed to minimize water contact with refuse, reducing leachate production.

The construction team used fly ash and slag in the concrete, asphalt with recycled roofing content and recycled steel, aluminum, gypsum board, insulation and glazing.

The project’s construction materials included 33 percent postindustrial or postconsumer recycled content, while 34 percent of the materials used were sourced from within 500 miles of the project site. More than 90 percent of the wood used in permanent features was certified as sustainably harvested by the Minneapolis-based Forest Stewardship Council.

Construction effort challenged

With Factoria handling more than 16 percent of King County’s solid waste, closing the existing transfer station during construction was not an option. Throughout the three-year construction project, garbage disposal and household hazardous waste collection services remained uninterrupted.

Previous attempts to modernize Factoria would have required closing to customers during construction. Only through a complex construction effort was the team able to build the new facility while maintaining operations.

The effort required a temporary 40-foot-tall and 300-foot-long shoring wall, four traffic pattern changes during construction and considerable earthwork. Services remained operational despite excavation of about 300,000 tons of soil and use of a large, temporary retaining wall to support an 80-foot elevation drop between the facilities.

The shoring wall location challenged the team throughout construction to come up with innovative ways to complete activities. Running through the existing transfer station trailer parking area required a temporary guard rail to maintain safe operations, which had to be constructed at night to not disturb operations. On-site operations staff had to develop creative ways to park and maneuver trailers.

Because the wall was so close to the existing transfer station and required significant dewatering, ongoing monitoring was needed to confirm the wall construction did not damage the existing facility.

Further, the general contractor had to be diligent about equipment and material movements, as the temporary wall was approximately 20 feet from new transfer station construction.

Getting materials to the site also proved difficult. The new stationary compactors were shipped via rail from Georgia to Washington and, because of their nearly 200-ton combined weight, they were limited to delivery between 2 and 5 a.m. on a Monday morning and to roadways designated for heavy loads, which required special permits.

Project completion also required constant communication with operations staff, who kept customers notified of changes at the facility.

With traffic moving around the site in various patterns depending on construction activities, safety was a constant consideration. The King County Solid Waste Division (KCSWD) worked with team members to design and implement additional temporary roads during phased construction, providing better separation of public, commercial and construction traffic.

Solid waste handling buildings are considered essential public facilities in Washington. Since Factoria provides a critical function in the community, the building is designed for immediate occupancy in the event of a natural disaster, including a major seismic event.

A standby diesel engine generator can power most of the facility, aside from the preload compactors, the box compactors in the recycling area and the yard waste tamping crane. This generator, along with an open top load out, allows Factoria Recycling and Transfer Station to remain operable even after major devastation.

Health at the forefront

The fully contained facility is built to maximize employee safety. The tipping area uses natural ventilation and a misting system for dust and odor control, providing cleaner air for employees and energy savings through the reduction of ventilation equipment use.

A panoramic view of the tipping floor is accessible from the supervisor’s office, employee break room and multipurpose space. Transfer station operators can maintain command while being separate from hazards including equipment, vehicle fumes, dust and other contaminants. The employee areas were also constructed from durable materials that do not contain formaldehyde or volatile organic compounds.

The tipping floor and household hazardous waste facilities have multiple hazardous gas detectors and alarms that are designed to automatically operate exhaust fans if lower levels of carbon monoxide, nitrogen dioxide or other contaminants are detected. If higher levels are detected, system alarms will notify staff of potentially unsafe conditions.

New design improves efficiency

The new facility compacts waste using two stationary compacters after recycling and other nonrefuse items are separated.

The old transfer station used top load containers where customers dumped waste into openings above trailers and a tamping crane compacted the waste. The stationary compactor design is an improvement over the previous system, allowing consistent 26-ton loads to leave the facility and reducing vehicle trips from 25 to approximately 17 per day.

“We’re committed to improving the efficiency and quality of the services we provide to county residents,” Dow Constantine, King County executive, says. “This new transfer station delivers. In just one example, the new compactors at Factoria improved the efficiency of each trailer hauled from this station, which translates to fewer trucks on the road and reduced climate pollution.”

The more efficiently the transfer station operates, the less time, money and fuel is wasted on queuing trash vehicles. With standard commercial collection trucks averaging about 3.5 miles per gallon of diesel, it is important that they move in and out of the station quickly. The new station is designed to allow commercial customers to enter the building, unload waste and exit within 5 minutes.

The new transfer station is also designed to adjust to any of King County’s future needs.

The county can change nearly the entire operation of the transfer station if needed within the next 50 years, which is the design life of the new facility. The building was constructed with five large doors that allow for traffic flow and direction to be flexible, and extra electrical hookups allow King County to incorporate new equipment into future operations. The flexible tipping floor provides 11 self-haul unloading stalls during weekday operations.

During weekends when self-haul traffic increases and commercial traffic decreases, operations may be oriented to use the commercial tipping area to better serve customers.

Public art ties into a greener focus

The project features 432 stainless steel wheels on the main retaining wall that convey a sense of motion. Abstractly tying into the recycling theme, its 75 percent recycled steel promotes public awareness for recycling and ties into Puget Sound’s passionate local cycling community.

An additional art piece at the administration building entrance offers another nod to recycling and motion. A poem etched into the lobby’s glass panels was originally included in a 1990s Factoria design that was put on hold. Shadows from the words arc across the lobby interior and change as the sun crosses the sky, creating a sense of motion.

A representation of a larger sustainability effort by the community, the grand-opening ribbon was not a ribbon at all, but a string of garbage and recyclable materials. Offering more recycling and disposal options than ever before—and completed on budget—the new transfer station has been heralded by the community.

Mary Shanks is a solid waste project manager based in HDR’s Seattle office, and John Carlton is the solid waste program lead based in the company’s Irvine, California, office. HDR is headquartered in Omaha, Nebraska. Visit HDR online at