The waste conversion industry covers a spectrum of methods for turning waste into renewable energy and fuel, including anaerobic digestion (AD), mass-burn incineration and gasification. Harvey Gershman, president of Gershman, Brickner and Bratton Inc. (GBB), McLean, Virginia, said waste conversion remains a work in progress in the U.S., but interest in this technology continues to grow with the desire to divert more material from landfills.
Gershman was the initial panelist to present during the opening session on the U.S. waste conversion industry during the 2017 Renewable Energy from Waste (REW) Virtual Conference Oct. 3 and 4, 2017.
Of the nearly 350 million tons of waste that were managed in the U.S. in 2013, he said the majority—64 percent—went to municipal solid waste (MSW) landfills. Twenty-one percent of the remaining material was recycled, 9 percent was converted into energy and 6 percent was composted.
Gershman broke down U.S. waste management infrastructure by facility type. (See the table on page S6.) Transfer stations, which numbered 3,350 as of October, are replacing landfills in U.S. cities, he said. The country has 586 material recovery facilities (MRFs), more than 9,000 curbside recycling programs and roughly 70 mixed waste processing facilities and hybrid MRFs. Residential waste also is going to nearly 2,300 composting facilities, 75 waste-to-energy (WTE) facilities and 25 AD facilities throughout the country.
“[Anaerobic digestion] is the fastest growing segment of new assets in the U.S.,” Gershman said, adding that the U.S. was home to no AD facilities in 2000.
He also acknowledged the decline of traditional mass-burn WTE facilities, saying that number in 2000 would have been “around 120 or so.”
BIG FISH, LITTLE POND
Gershman said landfills are still the big fish in the little pond—almost 2,000 landfills are located throughout the U.S. “Landfills are getting bigger in size and they are consolidating a bit, but we still have one heck of a lot of landfill capacity and landfills around the country,” he said.
Approximately 220 million tons of MSW were landfilled in 2013. If diverted from landfill, that amount of material would have created a nationwide investment opportunity of $120 billion and 50,000 jobs, Gershman said. “This is a pretty good economic opportunity, not to mention the environmental benefits.”
Collection, processing and disposal costs were important factors to consider, he said. “If you have an inefficient collection system for the 60 percent of the cost of solid waste, you’ve got a real opportunity to make that more efficient in whatever the various ways are—technology, policies—to put more money into the processing and disposal.”
The average tipping fee at WTE facilities is $68 per ton, competing with an average tipping fee of around $50 per ton at a landfill. But, Gershman said, those landfill fees depend on location and have been increasing over time. Tipping fees can reach as high as $80 per ton in the Northeast, while they can be as low as $36 per ton in western states. In 2013, tipping fees in the Northeast were $75 per ton on average, while in western states they were around $34 per ton, he said.
“These are posted rates. Contracted rates for significant tonnages may even be less,” Gershman added.
Waste composition also dictates why companies and municipalities might want to move toward renewable energy generation. For example, the U.S. Environmental Protection Agency (EPA) estimates one-third of the MSW stream that remains after recycling is made up of food scraps (23 percent) and yard trimmings (9 percent).
“These two big organic pieces, plus contaminated paper, represent a very significant opportunity for anaerobic digestion or integrating into a more controlled composting system,” Gershman said.
More than 20 organics facilities are in the planning stages in the U.S. They are mostly being developed by commercial waste generators, he said. This is because of the low number of households that separate and collect organics at the curb. “We have a long way to go before we’re getting food waste out of the kitchen [and] into a separate garbage pail, put in a yard waste container or just collected separately,” Gershman added.
Organic waste can be integrated into what he describes as ever-changing energy generation methods, since renewable natural gas can be a product of anaerobically digested organics. “To make a long story short, new coal capacity is disappearing, and wind and solar have been added,” he said, adding that natural gas has made the most gains by far.
In addition, Gershman said, pricing for natural gas has remained at a steady $3 per dekatherm because of hydraulic fracturing. Power production from natural gas, he noted, surpassed coal in 2016.
WHAT TO USE
Gershman described mass-burn incineration as the “mainstay” of WTE plants. Considerable contenders in this field are Covanta, Morristown, New Jersey; Babcock & Wilcox, Charlotte, North Carolina; and Wheelabrator, Portsmouth, New Hampshire. These companies use steam generated from burning feedstock, such as yard waste and MSW, to create energy.
The newest mass-burn facility is in Palm Beach County, Florida. The Solid Waste Authority of Palm Beach County’s facility has been operating commercially since June 2015 and combusts 3,000 tons of MSW per day, Gershman aid. The Babcock & Wilcox facility produces 581.8 kilowatt hours per ton of material processed.
European firms that are licensors or developers of this technology account for the majority of AD facilities being built in the U.S. Typically, there are two types of AD—high solids and low solids.
Two recent AD facilities include CR&R in Perris, California, and Blue Sphere in Charlotte, North Carolina. CR&R is a $100 million facility processing 84,000 tons of organic waste per year. It’s a high solids system that takes in residential food and yard waste and commercial food waste to generate compressed natural gas (CNG) for fleet fuel and pipeline-quality natural gas. The $27 million Blue Sphere facility takes in 156,000 tons of animal and food waste per year to create electricity and soil amendment.
Gasification, Gershman said, has “people in it, out of it and one that used to be in it that’s coming back into it.” It entails a starved-air partial-combustion process that produces synthetic gas (syngas). The syngas can be used for fuels as well as for electricity and typically is created from MSW, biomass or agricultural waste.
Plasco Conversion Technologies, formerly known as Plasco Energy Group, recently reemerged with new owners, he said. In 2011, the company contracted with the city of Ottawa, Ontario, to build and operate a 110,000-ton-per-year plant to convert MSW into electricity. Now it focuses on selling technologies to municipalities with existing MSW facilities, Gershman said.
Another type of waste conversion is plastic-to-oil technology, sometimes referred to as pyrolysis. It can help with the difficult-to-recycle plastics that pop up in waste streams. Pyrolysis uses thermal conversion in the absence of oxygen.
Many waste conversion processes require feedstock preparation. Processing technology from companies including Van Dyk Recycling Solutions, Stamford, Connecticut; Machinex, Plessisville, Quebec; and Bulk Handling Systems (BHS), Eugene, Oregon, often are found at the front end of waste conversion systems.
An example of a mixed waste processing facility that used front-end processing to extract recyclables and fuel feedstock was the Infinitus facility in Montgomery, Alabama. The $35 million, 80,000-sqaure-foot facility closed in October 2015, a little more than a year after opening. Gershman said the facility did not shut down because of problems with the equipment or end-product quality but because of a bad contract that “didn’t allow for service fee adjustments due to market conditions.”
LOOKING INTO THE FUTURE
Gershman concluded by talking about the circular economy, which he said was all the buzz at the Wastecon/ISWA (International Solid Waste Association) World Congress in Baltimore in late September.
“Let’s try to make things here with our waste and use it here in the U.S. or North America rather than shipping it to other countries to convert it to products that we buy back,” he said.
With landfill prices rising and the desire for diversion growing, Gershman said, waste conversion has the potential to thrive in the U.S.”
“As a bottom line, let’s keep in mind that waste is recyclable but it’s also very renewable,” he said. “Every time I look out on my street on Friday in my neighborhood, there are garbage cans at the end of every driveway with more waste, so it just keeps coming back.
“A lot less waste going to landfill is a lot better, in my opinion,” he continued. “And if your waste isn’t recyclable and it’s not organic, then what is it? It’s fuel or feedstock for something.”