ENVIRONMENTAL
Ken Graham | Davis Constructors & Engineers
Streamlining the Waste Stream
Anchorage’s new central transfer station
By Terri Marshall
I

n Anchorage, solid waste ends up at the regional landfill off Hiland Road. This includes ash and grit from the wastewater treatment plant as well as industrial and household refuse. Rather than drive to Eagle River, though, commercial haulers and individuals have the option of dumping in Midtown.

The city-owned Solid Waste Services (SWS) maintains a Central Transfer Station off Old Seward Highway, between International Airport Road and Dowling Road. The exact address flipped to the other side of East 56th Avenue last fall with the completion of a replacement facility. Opened September 8, 2023, the Central Transfer Station is expected to extend the life of the Anchorage Regional Landfill from approximately 2065 until 2085.

“Anchorage’s former transfer station was built in the 1970s when the city’s population was roughly half of what it is today,” says Kelli Toth, acting director of SWS. “The former facility also needed some safety upgrades, et cetera, so instead of retrofitting and cramming more into a smaller space—which wasn’t a viable solution—a new station was constructed.”

The new SWS Central Transfer Station provides additional space for processing refuse as well as more systems for diverting waste away from the dump. The $114 million edifice is a tool for extending the useful life of the landfill by an extra twenty years.

The Basics of Waste Transfer Stations
Waste transfer stations are where collected trash is temporarily held and sorted before being taken to a permanent repository. Residents and businesses may also bring hazardous waste and other solid waste to designated locations for special processing.

Transfer stations often operate hand-in-hand with material recovery facilities, which allows them to remove recyclable items from the waste stream. Depending on the type of waste, the items will potentially land at one of the following locations: landfill, incinerator or other waste-to-energy plants, hazardous waste facility, or a recycling center for shipment to a reprocessor.

Efficiently designed transfer stations feature a tunnel or drive-through area below the tipping floor. Transfer trucks drive into the tunnel, and after the garbage is tipped out, heavy front-end loaders push the garbage into the trucks. This saves money on transportation costs and eliminates excessive truck traffic through the community.

construction workers inside Anchorage's new Central Transfer Station
Few pre-engineered metal buildings anywhere in the world have a span as wide as the roof over the tipping floor at Anchorage’s new Central Transfer Station.

Ken Graham | Davis Constructors & Engineers

Design Considerations
The Central Transfer Station covers 26 acres and includes space for SWS administrative offices, residential and commercial waste disposal, and fleet operation. The architect and engineering firm of Tetra Tech was chosen to develop the design.

Tetra Tech designs specialized materials recovery facilities for municipal, commercial, and industrial clients that transfer, transport, and process various solid waste and material types. Leveraging the combined experience on more than 225 recycling, material recovery, co-composting, transfer, and maintenance projects, Tetra Tech began by considering the unique challenges in the Municipality of Anchorage.

Of note, the Anchorage facility was developed on a geotechnically challenged parcel which required surcharging before the start of construction. Other things taken into consideration during the design process were the high volume of commercial and residential users the Anchorage transfer station supports by providing a one-stop solution for waste. Facility planning included site feasibility and fatal flaw analysis, site review and selection, concept site layout and operations plans, concept building, equipment layout and operations plans, and financial and operational analyses.

Construction Phase
Anchorage-based Davis Constructors & Engineers was chosen to build the site’s seven buildings and 97,000-square-foot three-level tipping facility.

“We were brought into the Central Transfer Station project before the design was completed to provide pricing and schedule projections, shape the campus, and address the size of the buildings,” says Jed Shandy, project manager at Davis Constructors & Engineers. “One of the initial challenges for this and every large campus project is budgeting. For this project, we were able to use three pre-engineered metal buildings, which are manufactured and assembled quickly, leading to significant savings.”

Additional design innovations and material selections further aided in reducing costs. Notably, among the pre-engineered metal buildings, one is the largest clear span in Alaska and likely the largest nationwide. Pre-engineered clear-span steel buildings are self-supporting, keeping the area between the outside columns clear of obstructions.

By incorporating insulated metal panels for thermal resistance and maintaining stable indoor temperatures, capstone microturbines that convert a high percentage of fuel into electricity, solar panels, and electrical charging stations, Davis Constructors ensured that the Central Transfer Station was more sustainable.

Controlling garbage smells is always a concern, as well. “We put in fans on the roof of the tipping floors that feature six air changes per hour, which push the trash smell up into the atmosphere and away from areas where residents would smell it,” says Shandy.

With an additional focus on user friendliness for Anchorage residents and collection agencies, the new facility accommodates SWS collection vehicles, third-party commercial collection vehicles, contractor vehicles, and private sector vehicles to provide convenient waste management for solid waste, recyclable materials, household hazardous waste, and white goods (i.e., household appliances) with a strong emphasis on material diversion and reuse options.

Davis Constructors recently received two Parker, Smith and Feek Excellence in Construction Awards in recognition of the firm’s work on the SWS Central Transfer Station for Meeting the Challenge of a Job Over $15 Million – Vertical Building and Sustainability.

Benefits to Residents
For the new facility, one goal was to make diversion of materials more convenient than ever. The traffic pattern design separates the users and results in less wait time for everyone. Residential, commercial, and household hazardous waste for reuse, metal appliances recycling, and repurposing each have a designated entrance and exit. For those arriving at the Central Transfer Station to pay a bill, speak with customer service, or check out the observation deck overlooking the tipping floor, a separate entrance is also provided.

For residential drop-offs—including recycling, compost, and garbage—the process is fast and simple. Enter through the residential entrance and follow the road to the drop-off point. Carts designated for composting and recycling will be in place for drop off. Then toss garbage over the public wall onto the tipping floor.

At the public wall, comingled recyclables such as cardboard, paper, steel cans, aluminum cans, and #1 and #2 plastic bottles are accepted. Composting (kitchen scraps only) is accepted through October. The compost will be collected and sent to a farm in the Matanuska-Susitna Borough.

construction workers building the new Central Transfer Station
The construction of the new Central Transfer Station frees up the old station across 56th Avenue to convert into a Materials Recovery Facility, diverting organics and possibly plastics from the landfill as early as this year.

Ken Graham | Davis Constructors & Engineers

Additional Services
For household hazardous waste, things have really improved. The original station used a World War II train car as the collection office for these items. Today, residents pull under a carport and wait for the attendant to help dispose of their household hazardous waste, much like a full-service gas station.

Household hazardous waste includes metal appliances like stoves, water heaters, washers, dryers, scrap metal, and refrigerators that may contain chemicals that must be removed before recycling. Note that refrigerators must be empty of food, naturally, and the doors must be removed prior to drop-off. The household hazardous waste drop-off is easily accessible from the residential entrance, with as little fuss as possible.

The Central Transfer Station also features a Reuse Station. Toth says, “People often bring items like household cleaning products, paint, epoxy, motor oil, and others that aren’t empty. They just drop them off to get them out from under the sink, out of the shed, or out of the garage.”

If the containers are in good condition, they are placed on a shelf and Anchorage residents can come in and pick up whatever they need. “It’s Anchorage’s best-kept secret, and we need to do a better job letting people know about this free resource,” says Toth. Residents can bring up to forty pounds of materials per household per day to the reuse station without being charged a drop-off fee. Picking up materials from the Reuse Station is also free.

Reduce, Reuse, Recycle
Construction of new landfills requires extensive planning and comes at a price tag in the millions. Finding the land to construct new landfills presents additional problems. Yet no landfill lasts forever.

The United States produces an estimated 268 million tons of waste each year, with a projected 140 million tons going into landfills. Reducing waste helps extend the life of landfills, postponing the hassle of building a new one.

Using products more than once saves money and reduces the use of the resources needed to produce new products. And recycling has been steadily gaining momentum in Alaska for decades. Most communities throughout the state have some form of recycling program. For example, Alaskans for Litter Prevention and Recycling works with cargo shippers to backhaul recyclables at an affordable rate so the exported material can be sold in the Lower 48.

The team at SWS is continuing efforts to improve the environment. “We’re working on establishing a pilot commercial organics collections program,” explains Toth. “We have several breweries, coffee roasters, and other organic generators in Anchorage that we are working with to determine ways to dispose of the organics without adding them to the landfill, where greenhouse gas emissions from these organics cause additional environmental problems.”

The new transfer station creates the capacity at the former site across the street to handle organics—that is, if this SWS initiative is accepted and supported by stakeholders.

Toth says, “It is exciting to see so many local businesses actively seeking disposal alternatives, and we are excited to see how the pilot works.”