Food scraps and compostable products

August 15, 2016 | General

Compostable Products And Postconsumer Food Scraps

A recent blog exchange between a restaurant group and its organics collection service captures the challenges and opportunities around postconsumer food scraps diversion.

Nora Goldstein
BioCycle August 2016
Food scraps and compostable products

Photo by Bob Badstibner, AgRecycle

“Death of Composting” read the title of a blog posted in June by Ayr Muir, founder and CEO of Clover Food Lab, a restaurant group in Boston, Massachusetts. Startling, to say the least, and certainly compelling to read.
Muir’s blog described how Clover Food Lab, a Boston restaurant company, moved to 100 percent compostable products in 2010: “I’d spent 18 months trying to get to that point. The last hang-up was the compostable lids. I’d finally gotten a new packaging company to develop a compostable hot lid and we were able to move to 100% compostable packaging.”
Muir posted the blog after learning that Save That Stuff, Clover Food Lab’s organics collection service, had not been taking Clover’s separated organics to a composting facility — in this case the WeCare mixed solid waste composting site in Marlborough, Massachusetts — because the plant wasn’t taking organics at the time due to equipment repairs. Instead, those organics were being taken to a landfill. Save That Stuff had included Clover Food Lab on its “dirty route,” which was utilizing the WeCare’s mixed waste composting site, due to possible contamination in the material from noncompostable packaging.
Adam Mitchell, cofounder and CEO of Save That Stuff (STS) responded with his own blog, and a cheerier title — “Life Of Compost.” He explained why material collected from Clover Food Lab did not go to WeCare, and noted that STS is shifting away from front-of-the-house collection (postconsumer) and instead, will collect “food-only” from back-of-house. “In our industry, we find it increasingly challenging to find a processing outlet for the compostable dishware, utensils, and one-time use compostable cups,” wrote Mitchell. “The consumer market for these items advanced far faster than the end-of-life processing outlets. Farm-based composters have a limited tolerance for the compostable dishware, preferring food scraps.”
Toward the end of the blog, Mitchell noted: “At the end of this summer, a new Organics Processing Center will open at our facility in Charlestown (MA). We will accept Food-Only at this organics center. We will no longer be able to process compostable dishware/single-use service ware for composting — the items will be screened out.”

Magic Beans?

This situation in Boston brings to the forefront the opportunities and challenges with establishing collection programs to divert source separated postconsumer food scraps and Biodegradable Products Institute (BPI)-certified compostable service ware to composting facilities. The opportunities include capture of more source separated organics (SSO) that otherwise would go to the landfill or incinerator, enabling communities to achieve zero waste goals, and reducing methane emissions from disposal. The challenges include the potential for contamination from noncompostable “look alike” service ware, and concern on the part of composting facility operators that the certified bioplastics will not compost in their process.
While there is merit to those challenges, the reality is that many programs are successfully capturing and composting postconsumer food scraps that often include compostable products. Outreach and education, training and retraining, signage and visual prompts and instant feedback when contamination is found are core components. For those including compostable products, best management practices include establishing protocols to ensure they are BPI-certified (BPI is the North American certifier), minimizing exposure to “look alikes,” testing the compostability of the products at the composting facility and creating infrastructure (e.g., equipment, composting methods) to facilitate complete biodegradation.
AgRecycle, an organics collection and composting company in Pittsburgh, Pennsylvania, has been processing postconsumer food scraps and compostable products for at least a decade. Carla Castagnero, president of AgRecycle, had this reaction upon reading the blogs: “We do not have magic beans at AgRecycle. Yet, we somehow manage to get these products to compost and break down per their mission. Why does this myth persist that products don’t break down? I hear this from composters who have never even tried to work with these materials. I feel that the only legitimate concern voiced was that you do get an increase in noncompostables when accepting front of house organics, but that only happens from the untrained public or when there is employee turnover.”
Castagnero emphasizes the critical importance of having the equipment necessary to properly compost compostable products. In an interview with BioCycle in 2014, she explained AgRecycle’s protocol: “The first essential element is doing a pregrind. A composter would never throw a log in a windrow. Certain streams are organic and acceptable but they just need preprocessing. It is that simple for compostable products. …. Most of the compostable products we receive come in from small restaurants that also include their corrugated in with the food scraps. Typically these restaurants don’t generate enough corrugated to warrant a separate collection as a recyclable. The second reason is that I can’t stand litter. And the compostable cups will blow out of the windrow if they aren’t preground.”
AgRecycle uses a Roto-Mix mixer, size-reducing the material to around 2 inches. The company avoids putting anything over 4 inches in thickness in the Roto-Mixer. “The food scraps, compostable products and the corrugated are the only materials on our site that see the mixer,” notes Castagnero. “We have a grinder for yard trimmings. And typical grinders don’t handle corrugated well — it just flies through as a sheet. … Finally, the key to achieving biodegradation within the timeframe of a facility’s composting process is making sure piles reach and maintain thermophillic temperatures as required and getting the microbial population where it needs to be.”

Added Bonus — More Food Scraps

And there is a bonus. AgRecycle found that allowing generators to include BPI-certified compostable products in their postconsumer food scraps stream actually increases the amount of food scraps captured. Castagnero — who presented these findings at the BioCycle West Coast Conference in April in San Diego — examined food scraps capture rates from cafeterias that went from back-of-house (BOH) food scraps only to front-of-house (FOH) and BOH (BOH+FOH). The analysis sorted the cafeteria data as follows: using no disposables; using noncompostable disposables; and using all compostable food service ware (CFSW). Each customer had been a BOH only account for at least 10 months prior to switching. All of these venues are self-busing by the customers.
The data reflects totals captured in a 3-year period beginning 6 months after the switch to BOH+FOH:

  • No disposables: 62% increased food scraps capture rate
  • With noncompostable disposal service ware: 9% increased food scraps capture rate
  • With CFSW: 78% increased food scraps capture rate

For venues that were always BOH+FOH customers and always used disposables but then switched to CFSW only, the food scrap capture rate increased approximately 72 percent. Castagnero reported that the amount of CFSW in a food scraps container from customers using compostable CFSW is extremely variable and cannot be generalized into an average. Overall, the percentage range of compostable products is very broad — from 5 percent to 90 percent per load.
Contamination rates, by volume, for generators switching from BOH to BOH+FOH, are as follows:

  • BOH+FOH with no disposables: 0.75%
  • BOH+FOH with noncompostable disposable service ware: 3.5%
  • BOH+FOH with CFSW: 2%

Castagnero’s takeaway from her data analysis: “Using compostable food service ware products absolutely changes in-house cultures regarding disposal and composting, and expands composting beyond the kitchen and dining room.”
In AgRecycle’s case, accepting postconsumer food scraps and CFSW has not had a negative impact on the company’s compost marketability. In mid-June, AgRecycle was seeing an increase in compost sales over the year to date from 2015, by 39 percent. And it was selling out of some grades of compost. “We completely sold out of our highest end product, one-quarter-inch, and only a few days supply left of our three-quarter-inch compost, until our next curing batch was released on the 18th of July. We only had three-quarter-eighth inch left.”
In our 2014 interview with Castagnero, she also emphasized the critical importance of being knowledgeable about the compostable products on the market. “We believe getting knowledgeable has been a key to our success in managing these items,” she said. “For generators that want to divert compostable products to AgRecycle, we will go through what they can buy and help them choose products.” This goes hand-in-hand with AgRecycle’s “all or nothing rule.” The company often receives requests from generators about wanting to divert only cold cups, for example. “We will not let generators divert cold cups until every cup in their food scraps stream is compostable,” Castagnero added. “This is eye-opening for some of our new accounts. But the turnover of food service workers is extremely high, whether it is at corporate cafeterias, sports and entertainment venues, colleges or restaurants. It is terribly unfair to expect the generators to continually train and retrain employees. If we tell them that every cup used has to be compostable, it is a no brainer.”
AgRecycle highlights the fundamental reality that to successfully divert postconsumer food scraps, organics collection services need to match these feedstocks with processing facilities that have appropriate capabilities, not the other way around. “Some farm composters and anaerobic digestion facilities are specifically set up to handle postconsumer food scraps, including compostable products and food-soiled paper, but many are not, preferring the low hanging fruit of preconsumer food scraps or just yard trimmings, which take less work,” notes Rhodes Yepsen, Executive Director of BPI. “Communities and businesses across North America are seeking to keep all organics out of landfills and incinerators, but we will not be able to accomplish this with a collection and processing infrastructure dedicated to preconsumer food scraps. AgRecycle is a large-scale facility that works with generators to achieve zero waste, collecting postconsumer food scraps with only certified compostable products, with the equipment and knowledge for processing those materials, and manufacturing a top-shelf finished compost that frequently sells out. Those are AgRecycle’s magic beans!”
Correction, September 9, 2016:
The article erroneously reported the WeCare Marlborough, Massachusetts site closed temporarily due to odors.

Sign up