Biowaste : Biowaste in the USA: Composting and Anaerobic Digestion are gaining ground

Cover montage WMW 1/22
© Weka/Kellermayer

The numbers are staggering. According to a 2018 report by the Commission for Environmental Cooperation (CEC), an offshoot of the North American Free Trade Agreement (NAFTA), the US generates approximately 207 million metric tonnes of organic waste –including food waste, yard and garden waste, paper products, wood other than construction and demolition debris, and pet waste ­– each year. Of that total, roughly 65 million tonnes are diverted and the other 142 million tonnes end up in landfills.

Across the globe, landfills are the third biggest human-caused source of methane, which is more than 25 times as potent as CO2 at trapping heat in the atmosphere. This methane is mostly created by organic waste in landfills.

Seeing the negative impacts from landfill on surface water, groundwater, soil, air and human health, the EU established strict rules and goals to divert organic waste from landfills in its 1999 Landfill Directive. “The generation of leachate can contaminate groundwater and methane is produced, which is a potent greenhouse gas. In addition, where recyclable waste is landfilled, materials are unnecessarily lost from Europe’s economy,” the EU stated. This means that landfilling is the least preferable option and should be limited to the necessary minimum. As a result, both composting and anaerobic digestion (AD) – and waste incineration for that matter – have become well established over the years as a way to treat organic waste. Collecting systems, public education and processing technology, not forgetting end markets, have matured up until the present day. In the US, comparable bills have been passed only in the last couple of years, giving the European market a head start of about 20 years.

35% of the waste stream is food, paper and compostable products which could have been composted
Frank Franciosi, USCC

Composting in the US

Having said that, in the 1990s some US states, such as Virginia, started passing yard waste bans for landfilling, paving the way for composting. “The main driver back then was to save landfill space,” says Frank Franciosi, Executive Director of the US Composting Council (USCC). “The main driver over the past 15 years has been to divert food scrap from landfills for the same reason and also to reduce methane emissions. We are seeing a steady increase in new facilities, facility expansion and the conversion of yard waste facilities to accept food scrap.” Because out of the approximately 5,000 composting facilities in the US today, only around 10% are permitted to accept food scrap.

All composting facility permits are regulated by each individual state and very often there just aren’t any permitting regulations. In some states very little food waste ends up in landfill or incineration. California is a leading example of a state that is trying to keep organic material out of landfills. But in many parts of the US such as Florida and Texas, the majority of food waste is collected with the rest of the trash and ends up in a landfill. “But it’s the heaviest portion,” Franciosi says. “35% of the waste stream is food, paper and compostable products, which could have been composted.”

More and more composting facilities that up until now accepted only yard waste start treating food scraps as well.

- © Fevziie -

In order to increase composting infrastructure in the US, Franciosi sees various hurdles to overcome:

  • inconsistent permitting regulations from state to state
  • lack of industry data and tracking
  • lack of investment opportunities on the state and federal levels
  • lack of consumer education and outreach about the benefits of composting and compost use.

One big problem in composting facilities is the contamination of the waste stream. It is complicated and cost intensive to remove non-compostable material. Apart from educating people and raising awareness, he sees the number one issue as the labelling and identification of compostable products. “There is a need to standardise on a national level an easy way to label and identify these products in the food scrap steam. This can be accomplished by colour and coding – on the products and on the bins – and should be regulated by states,” asserts Frank Franciosi. Furthermore, lookalike products that are not certified as compostable need to be heavily penalised. Compost manufacturers should be compensated for processing these products and all of these products need to be food scrap related, according to Franciosi. “In other words, compostable products should help divert food scrap to composting facilities. These products should also be field tested in the facilities that are considering accepting them as feedstocks to ensure that they will break down.”

Composting is of course more popular in agricultural and suburban areas where there is a big market, as David Biderman, CEO of the Solid Waste Association of North America (SWANA), explains: “Composting is a nice thing for the planet but unless you can make money out of it, it doesn’t make economic sense.”

AD in the US

Even though composting is a more accepted practice in the US – almost all states have permitting regulations for composting – anaerobic digestion plants are gaining ground. “The biogas industry has been growing faster than it ever has in the US,” says Patrick Serfass, Executive Director of the American Biogas Council. “Overall, the industry grew by about 5% last year. We saw the biggest growth in renewable gas (RNG) facilities. Nine out of ten new projects are developed as RNG projects. That sector grew by 46%.” The number of operational projects also grew by 46% according to Serfass, while the number of those in construction grew by 42%. “So we are experiencing not just an increase but also an acceleration of growth in the biogas sector.”

Even though there is growth nearly everywhere because, well, there is organic waste nearly everywhere, there seemed to be a little more in the western half of the US last year. Right now, manure-based projects are the most popular, followed by food waste and wastewater sludge, in terms of interest from the project developers.

As the industry grows, so does the American Biogas Council. “There are companies applying basically every day,” says Serfass. “A lot of companies are interested in entering the market because there is a huge opportunity. We have a lot of organic waste and not a lot of it is getting recycled.” There might be some consolidation in the future but right now the industry is just growing.

Want to know more about biomethane production? Read here and here!

The recycling of organic waste is slowly gaining momentum in the US. Experts see a huge market for the biogas industry.

- © Stephan Leyk -

It is only a decade since the biogas industry in the US really started to grow in earnest. Historically, there would be anaerobic digesters close to wastewater facilities because it helped reduce the wastewater sludge. Only later would they start using the biogas produced during anaerobic digestion.

Now there are over 2,200 sites producing biogas in all 50 states: 250 anaerobic digesters on farms, 1,269 water resource recovery facilities using an anaerobic digester (about 860 currently use the biogas they produce), 66 stand-alone systems that digest food waste and 652 landfill gas projects.

Compared to the European market with its almost 18,000 anaerobic digesters, this does not seem much. “It’s no secret that the European market is much more developed than the US market. But we have the opportunity to build at least 15,000 new systems. So the market can easily be as big if not bigger than in Europe,” explains Serfass. “We are just at an earlier stage in growing that industry.”

This also means that at this point, there is not yet an established market for the digestate. One reason seems to be that people just don’t know what it is and that it can be used as a fertiliser. Many AD plants pay to have digestate removed, transported and applied to land. It is therefore considered an expense and not a revenue. But Serfass is convinced that that is where the industry is heading: getting revenue from digestate, tipping fees and gas.

We are experiencing not just an increase but also an acceleration if growth in the biogas sector.
Patrick Serfass, American Biogas Council

Incentives necessary

The development of organics recycling, be it composting or the much more cost-intensive anaerobic digestion, is influenced by financial incentives, such as subsidies or feed-in tariffs, tipping fees and policies.

In the EU, tipping fees for landfills are much higher than in the US. In Denmark they are 185 dollars per tonne and in Germany 165 dollars per tonne, while the average tipping fee in the US in 2020 was 53.72 dollars per tonne according to the Environmental Research & Education Foundation (EREF). “It costs 25 dollars a tonne to dispose of trash in Texas or Arizona. You can’t compete with that,” explains SWANA’s David Biderman. “In the places where there are more aggressive food waste diversion policies, the cost of disposal is higher. So that creates more of an economic incentive as well as a political incentive to create a policy that provides for separate food waste disposal.”

The EPA issued a National Recycling Strategy in November last year that is broader than just the traditional recycling of plastic, paper, glass and metal. The goal is to divert 50% of trash away from landfill or incineration by 2030. “So for the first time in my lifetime there is a national strategy,” says David Biderman. “And now the tough part is going to be implementing it: creating tools and incentives and getting the states to play along. And SWANA is going to be closely engaged with state agencies, recycling companies and local governments to help make it happen. But we are in the very, very early stages of this process.” In Biderman’s view, if more states followed the lead of New England and passed laws that gradually restricted food waste disposal from commercial generators over time, that would create an incentive for those facilities to site AD facilities in that part of the country.

According to Patrick Serfass, the EPA National Recycling Strategy is a good step. But policies will only have an impact if they are enforced. “There are currently nine states with organics recycling policies but in order to have an effect, you need enforcement. And that enforcement needs to be strong. And we are not seeing a lot of that at the moment.”