What’s new in waste conversion technology

Waste Today: Shifting markets and changing demand might help some waste conversion technologies finally gain more widespread acceptance

By now, solid waste managers know the overseas markets for traditional recyclable materials have been inverted due to import bans and restrictions put in place by China. To boot, China’s actions are having a ripple effect across the globe as more countries adopt waste and material bans or expand their restrictions.

While this is certainly affecting the industry, it will not be the end of community-based recycling programs as we know them. Thanks in large part to these recent challenges, the emphasis in recycling is now on quality as opposed to quantity.

Many community programs are dropping low- and no-value materials to focus on the “Big Four”: corrugated cardboard, No. 1 and 2 plastic containers, and metal containers. The value for mixed paper and mixed resin plastics is currently low, and in some instances, recycling has become the highest cost waste management option. So, what can forward-thinking North American solid waste managers and policy leaders do other than accept, or even increase, the amount of solid waste being sent to landfill?

Traditional combustion-based waste- to-energy plants are highly reliable with predictable costs, but given today’s low electricity values, they are not economical, which is why maybe now is the time to take another look at emerging waste conversion technologies. A lot of potential exists for waste conversion solutions, and several technology suppliers are even advancing projects and starting up their first full-scale commercial facilities this year.

Mixed waste processing with mechanical biological treatment (MBT)

MBT encompasses a broad array of technologies that use mechanical and biological processes to recover recyclables, stabilize organic material, generate energy and produce products.

MBT facilities have enjoyed broad adoption across the European Union (EU), where they are used to recover recyclables and produce solid recovered fuel (SRF) that can serve as a substitute for coal. By one count, there are over 300 MBT facilities operating in the EU presently. Large industrial firms and, more specifically, cement manufacturers in the EU, have adopted aggressive SRF-utilization goals as a component of their corporate sustainability plans. The carbon content of SRF is about 50 percent biogenic, and several companies occupying the space (Buzzi Unicem, LafargeHolcim, Titan, etc.) also operate cement manufacturing facilities in the U.S., which aid in meeting their worldwide sustainability goals.

Two of the emerging waste conversion companies, Entsorga West Virginia and RePower South, are putting the finishing touches on MBT facilities designed to produce an alternative solid fuel from municipal solid waste here in the U.S.

Entsorga West Virginia in Martinsburg is a partnership between Apple Valley Waste Technologies, Entsorga USA and BioHiTech Global. It is the first application of Entsorga Italia’s proprietary High Efficiency Biological Treatment (HEBioT) technology in the U.S. This technology utilizes a system of mechanical equipment to preprocess inbound waste, removing dry, oversized constituents prior to placing the remaining high-moisture material into holding bunkers for biological treatment. Air is drawn through the stored waste mass, drying it to a desired moisture level. Once dried, the treated material is extracted from the bunker and further processed to recover valuable material and remove unwanted contaminants, and then it is sized to create a valuable fuel product. The fuel product is sold to a local cement manufacturing facility.

RePower South of Charleston, South Carolina, is a privately-owned firm. The company has begun operation at two facilities this year—one just outside of Charleston and a second in Montgomery, Alabama. The South Carolina facility was a greenfield development project, while the Montgomery facility encompassed the refurbishment and remodeling of a failed waste processing facility. Both the Charleston and Montgomery facilities utilize mechanical systems to screen in-bound waste for undesirable contaminants, recover valuable materials and size the balance of the waste material to create a valuable fuel product for use as a coal substitute. The Charleston facility is privately owned and was financed by tax exempt bonds and private equity. The Montgomery facility is publicly owned with RePower South financing the facility refurbishments and the fuel production system.

In the public sector, the Wasatch Integrated Waste Management District (WIWMD) in Utah is constructing what will be a publicly owned and operated mixed waste processing facility. For many years, the WIWMD operated a traditional mass-burn waste-to-energy facility, which sold electricity to the local power grid and steam to a nearby U.S. Air Force base. When the base greatly curtailed the amount of steam it purchased, the waste-to-energy facility was no longer economical. Instead of falling back to landfilling, the WIWMD elected to develop a mixed waste processing facility. The processing facility will be used to increase the volume of valuable recyclables recovered from the waste stream and will be able to produce an engineered fuel for a nearby cement kiln. The facility is fully financed, and design engineering is underway, with groundbreaking slated for later this year.

Fiberight LLC has its own version of MBT technology, which is being demonstrated at a new facility outside of Bangor, Maine. The facility is designed to recover and produce an array of products from 600 tons per day of municipal solid waste (MSW) and single-stream recyclables. The facility’s front-end processing system will screen inbound material and recover traditional recyclables such as containers, OCC and metals. The remaining material will then be subjected to a wet processing system wherein low-quality fiber will be recovered and upgraded into market-quality fiber pulp. Within the wet processing system, soluble organics, such as food waste, will be recovered and eventually converted into renewable natural gas via the facility’s in-house wastewater treatment plant. Finally, plastic film will be recovered for use as an engineered fuel. The facility is privately owned and was financed through a combination of equity from Ultra Capital, a sustainable infrastructure fund and tax-exempt bonds. The facility will serve 104 communities in Maine.

Mixed waste composting and anaerobic digestion

Composting alone or in combination with anaerobic digestion is a proven strategy for select, source-separated constituents of the solid waste stream, but successful applications with the full municipal waste stream are still limited. A limiting factor appears to be the difficulty of cleaning the resultant compost to make a relatively contaminant-free product. Cleaning technologies from Europe are available, but they are considered expensive in the U.S. market. Mixed MSW compost is a mostly unknown commodity in the environmental regulatory arena, so market development work is required to successfully advance projects.

Waste to biofuels

Technologies to convert MSW to renewable transportation fuels, primarily cellulosic ethanol and diesel, have long captured the eye of visionary entrepreneurs. The U.S. Environmental Protection Agency’s (EPA’s) Renewable Fuel Standard (RFS) can provide indirect subsidies approaching $200 per ton of MSW for cellulosic ethanol. Some federal loan guarantees can significantly lower a facility’s cost of capital, which is important as waste-to-biofuels facilities are very capital intensive. A 1,000-ton-per-day waste-to-biofuel facility can cost over $500 million to construct, so these technologies are generally economically feasible only at sizes of 1,000 tons per day or more.

Enerkem Alberta Biofuels, located outside of Edmonton, Canada, is the only commercially operating MSW-to-biofuels facility in North America. Designed to produce 10 million gallons per year of ethanol, construction of the facility began in 2014. In 2016, it produced bio-methanol as a renewable chemical feedstock. In 2017, it was certified by the U.S. EPA to produce and sell bioethanol through the U.S. Renewable Fuel Standard. Enerkem, its investors and partners are developing additional facilities in North America and Europe.

Fulcrum BioEnergy has begun construction of its Sierra BioFuels facility outside Reno, Nevada. Once completed in 2020, the facility is expected to convert 175,000 tons per year of MSW into low-carbon Syncrude, which can be further processed into biofuels at a nearby oil refinery. The facility is privately owned and financed through a combination of private equity and tax-exempt bonds.

Chemical recycling of plastic waste

A relatively new strategy for waste conversion is the chemical recycling of plastic waste. Chemical recycling of plastics involves the conversion of plastic waste into a liquid hydrocarbon that can then be used to produce new products. The conversion process typically involves a pyrolysis technology, which is akin to gasification. With the heightened visibility of the impact of single-use plastics on the environment, this is a sorely needed technology in the current market.

There are several technology providers developing their first chemical recycling facility. Most recently, Brightmark Energy broke ground on its first commercial scale plastics-to-fuel facility in Indiana. The facility is designed to convert 100,000 tons per year of mixed waste plastics into 18 million gallons per year of low-sulfur diesel and waxes. Additionally, Agilyx has operated a demonstration facility outside of Portland, Oregon, for several years.

Conversion to electricity

Noticeably absent from any list of projects coming online are those deploying high-temperature processes, such as gasification or pyrolysis, to generate electricity. This is a reflection of electricity being a relatively low-value product that does not support the capital intensity of these complex technologies at the moment. As long as fracking continues to provide an abundant supply of inexpensive natural gas for electricity production in the U.S., this fact is unlikely to change.

What’s next?

Solid waste visionaries have long waited for advanced waste conversion technologies to move from the research stage, through the demonstration phase, and into commercial operation. With the current activity in this space, 2019 might be the year wherein that wait finally pays off. However, it may take another two to three years of successful operation with several of these technologies before the most conservative of solid waste managers accept them into their community waste management system.

https://www.wastetodaymagazine.com/article/whats-new-in--waste-conversion-technology

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