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In one of the first cooperative agreements between a large urban center and a waste-to-biofuels company, the city of Edmonton in the Canadian province of Alberta continues to blaze a trail in waste management.

The city has amassed what it calls the largest collection of modern, sustainable waste processing and research facilities in North America. This Edmonton Waste Management Centre (EWMC) is operated by the city in cooperation with a collection of industrial partners, including GEEP for electronics recycling, Grey’s Paper Recycling Industries for recovered fiber and textiles and, most recently, Enerkem for converting nonrecyclable, noncompostable waste to advanced biofuels.

The center also is home to a materials recycling facility (MRF), a composting facility, a construction and demolition recycling facility, an energy research facility and a landfill. The virtual campus of 22 buildings and retention ponds is located on a 550-acre parcel of land that is tucked within one of the curves of the North Saskatchewan River on the northeastern edge of the city. This sensible yet uncommon approach appears to be the perfect venue for integrating the three R’s of the environment—reduce, reuse, recycle—and for adding a fourth one: recovery.

Waste To Biofuels
The newest piece of Edmonton’s waste management center is the Enerkem Alberta Biofuels Facility, still under construction on a 12-acre parcel of the site leased by Montreal-based Enerkem through its affiliate Enerkem Alberta Biofuels.

The city set up its integrated waste management system in 1993, a long-term plan to increase diversion rates by recycling and composting. In recent years the city has looked to increase its diversion rate from 60 percent to 90 percent, identifying thermal conversion technologies as a possible solution.

More specific plans emerged in 2008 when the city signed a 25-year agreement with Enerkem, promising to supply 100,000 dry metric tons of sorted municipal solid waste (MSW) as feedstock for its waste-to-biofuels gasification process. In return, the city has the option to purchase at least some of the tens of millions of gallons of renewable liquid fuel Enerkem says it will be able to produce.

It’s all part of the Edmonton Waste-to-Biofuels Project, a CA$207 million public-private collaboration including three major facilities within the EWMC: an integrated process and transfer facility (IPTF), the advanced energy research facility and the Enerkem Alberta Biofuels facility. About CA$29.5 million of the project is being funded by a provincial grant from the government agency Alberta Innovates-Energy and Environment Solutions.

“The whole project was basically put in place to deal with residual waste streams from our recycling and composting operations,” says Jim Schubert, general supervisor of conversion technologies, waste management services and infrastructure services for the city.

Enerkem says the Edmonton biofuels facility will be the world’s first major collaboration between a metropolitan center and a waste-to-biofuels producer to turn nonrecyclable, noncompostable MSW into methanol and/or ethanol. This facility also is expected to help the city reach its 90 percent diversion goal, because it will use much of what has been landfill-bound waste to create renewable fuels.

Marie-Hélène Labrie, vice president of government affairs and communications for the company, says Enerkem’s process is unique because it starts with the production of a chemical grade synthesis gas from mixed waste that is capable of being converted to a variety of liquid biofuels or chemicals.

“We’re focusing on using waste to produce cellulosic ethanol to help reduce landfilling while also providing a clean fuel,” Labrie says. Enerkem’s is a modular approach that produces a chemical-grade synthesis gas, converts the syngas to methanol using catalysts, then converts the methanol to ethanol.

“We plan to generate revenue right away with the production of methanol,” Labrie explains. “It’s a multiproduct technology platform, so we have the flexibility to produce what we want as an end product.” In Edmonton, she adds, “We are focusing on cellulosic ethanol, but we have the flexibility to sell methanol as well if we want to.” Plans call for the facility to start methanol production in late 2013 followed by ethanol in 2014.

Labrie says tests conducted at its Quebec pilot facility (in Sherbrooke) and demonstration facility (in Westbury) have validated the company’s process using the city’s prepared feedstock. Construction on the Edmonton facility started in 2010 and was close to completion as of July 2013.

Feedstock Preparation
One of the key details, Labrie says, has been integrating the city’s waste with Enerkem’s technology. “The feedstock preparation was the link between the two,” she says.

This link, for all intents and purposes, is the large white building located on the west side of the EWMC, a virtual nerve center where Edmonton’s municipal solid waste makes its first stop and where other residuals end up for future disposition.

Opened in 2012, the IPTF—a CA$90 million investment—offers three functions, says Schubert: transfer of waste before going to landfill, preprocessing of waste and production of refuse-derived fuel (RDF).

The majority of materials received at the IPTF is black-bagged rubbish that is preprocessed to remove smaller organics for transfer via conveyor to what is described as the largest aerobic composting facility in North America. Items less than 5 inches in size go to that facility, while the larger fraction is sent through the RDF preparation system. Once the smaller fraction is processed for compost, Schubert explains, anything greater than three-eighths-inch returns to the IPTF. “Things like bottle caps, film plastics, rigid plastics, pieces of wood,” Schubert explains. “If it’s not turned into compost, it will get screened out and will come back to this RDF area.”

The turn-key RDF system was designed by Vecoplan LLC, based in Archdale, N.C., and includes receiving, preshredding, conveying, screening, separation and reshredding to produce the feedstock for the adjacent waste-to-biofuels facility. It is a complex system that is set up to handle the sorted rubbish as well as residues from the composting facility and the single-stream MRF.

It all begins with the Hurricane VVZ310 T dual-shaft shredder that preshreds the material to a size of 4 inches or less, “so we have a consistent size to begin with,” Schubert explains, before unwanted or unsuitable materials are removed.

An overbelt magnet removes ferrous materials before the stream is split into two identical lines. Waste screens filter out minus-1-inch materials, which go back to the composting operation for another chance to cull organics. “Yard waste has over 50 percent moisture in it,” explains Schubert. “You don’t want that going to the waste-to-biofuels facility.”

Next, the streams pass through a wind sifter to remove heavy materials, such as rocks and glass. The more desirable lighter—and higher Btu-value—materials, such as plastic and papers, will continue to the next step of the RDF operation.

The stream then passes through an eddy current separator for removal of nonferrous materials and finally through one of the two VEBS 2500 reshredders for sizing to the final minus-2-inch size. The RDF is now ready to be conveyed on the patented Vecobelt conveyor connecting the IPTF with Enerkem’s facility.

“In order for a gasifier to work well, you have to try to make waste homogenous,” explains Schubert. “We do that by, one, removing all the organic material, which causes a lot of fluctuations in the waste stream.” Then, valuable materials such as metals and inert materials, such as rocks and glass, are removed to create an RDF with the right Btu value for Enerkem’s process. “At the end of the day we have a much more homogenous material than garbage off the streets,” he says.

The spongy, confetti-like RDF is about 30 percent plastic and 20 percent textiles, with the remainder comprising wood waste, paper and trace amounts of organics. Schubert notes that rubbish is processed separately from MRF residues because of their varying moisture contents.

Jeff Wolfe, North American sales manager, waste, alternative fuels and energy for Vecoplan says, while Vecoplan has built similar RDF systems throughout Europe and North America using similar equipment setups, none have had the exact same types of input streams nor do they produce the same sort of RDF.

“We’re taking the specification of what the final processing needs are and we’re designing our system to fit that,” he says. “The feedstock coming in would determine what type of equipment as far as shredders and reshredders and everything else in between that we would use.”

While the RDF preparation system has been commissioned, as of press time it was operating only for a few days each month and will not reach capacity until the biofuels facility is up and running. It is designed to produce about 25 tons of feedstock per hour.

Once inside Enerkem, the RDF is stored in a patented bunker system also made by Vecoplan. There, seven huge bunkers can store the different RDF feedstocks for blending by Enerkem to achieve a more consistent material. Combined, the bunkers can hold a few days’ worth of feedstock, Wolfe says.

A Conservative Approach
While the biofuels component is certainly the most advanced part of Edmonton’s process, Schubert says the city has taken a conservative view.

“The project was based on first seeing that we could maximize the three R’s and is now looking at the fourth R [recovery] to handle what’s left over.” That may be what makes Edmonton’s approach unique.

“We sold the project as an add-on to our existing system. We said ‘we’ve recycled and composted as much as we can. Now we’re looking at the next step.’” Schubert says that could be one reason the city gained approval and permitting for the facility so quickly—in about a year’s time.

He says Enerkem’s biofuels may be sold locally, and the markets are there. In Canada, all gasoline blends must contain at least 5 percent ethanol, which is one potential market for the fuel. “In a few years’ time hopefully our garbage will be fueling our vehicles, so to speak,” Schubert says. The 38 million liters of ethanol that the facility should be able to produce translates to about 16 percent of the province’s need, he says.

The author is a managing editor with the Recycling Today Media Group.