A research study provided households with compostable Ziploc bags and tracked them from homes to a commercial composting site via the grade school. Material on tarp represents an audit sample of food scraps from a school cafeteria.

May 4, 2016 | General

Finding Common Ground In Quest For Clean Organics

A compost manufacturer and a consumer packaged goods manufacturer collaborate on a compostable bag research trial in Washington State.

Susan Thoman and Jeff Zettle
BioCycle May 2016

Compost manufacturing has evolved over the years to meet demand to accept more varied feedstock streams on the front end, and to produce high quality compost on the back end. Included in this more varied feedstock stream are food scraps and assorted food packaging. In turn, compost manufacturers are adapting their feedstock acceptance criteria. And packaging manufacturers are expanding availability of compostables within the food service manufacturing space. With conventional plastic single-use containers and food-related packaging the bedevilment of trash piles and the vast plastic patches floating in the ocean, innovation in the arena of compostable products has the potential to redirect recoverable food from the garbage pile over to the compost pile. It is that potential that brought together a compost manufacturer and a consumer packaged goods (CPG) manufacturer to collaborate on a research project.

A research study provided households with compostable Ziploc bags and tracked them from homes to a commercial composting site via the grade school. Material on tarp represents an audit sample of food scraps from a school cafeteria.

A research study provided households with compostable Ziploc bags and tracked them from homes to a commercial composting site via the grade school. Material on tarp represents an audit sample of food scraps from a school cafeteria. Photo courtesy of Cedar Grove Composting

When Cedar Grove Composting started curbside collection and composting of yard trimmings in 1989 in the Seattle, Washington region, contaminants in the incoming stream consisted primarily of clippers, trowels and black plastic bags used to collect leaves and twigs. Through extensive outreach and education, the contamination from these items ultimately fell to a manageable level with early collaborative support from cities, counties, waste haulers and residents.
With that historical knowledge, the expectation was that when postconsumer food scraps were added to yard trimmings years later, there would be contamination in the early stages of program initiation, but that over time, these levels would subside with education. Unfortunately, that was not the case. From the early days of “yard waste only” to the postconsumer food era, the growth and unrelenting preponderance of plastics and contaminants related to food composting programs continues to be a daunting challenge, threatening the economic viability and ongoing growth of urban composting programs. Basically unchecked by the emerging use of curbside automated collection trucks and growing consumer confusion, the time has come to find new partnerships and ways to solve waste problems while focusing on solutions that turn the plastics contamination tide in the opposite direction at compost manufacturing sites.
In that context, the advancement of compostable packaging alternatives destined for commercial composting operations can present both an added risk of increased contamination, or may hold the key to lowering contamination by replacing current noncompostable contaminants with certified compostable products that easily transform into biomass and water within a commercial composting system. Broad-based solutions need to be developed that involve the collaborative teaming of like-minded organizations willing to charter unknown territory together. Why? To solve contamination problems and enhance recovery of food waste, compost manufacturers and packaging manufacturers need to rely more heavily on facts than assumptions. Forging research and methodologies to develop a platform of common ground between the manufacturing floor and the tipping floor starts with mutual appreciation of both ends of a large and interrelated system. SC Johnson and Cedar Grove Composting have created that common space, and are working to continue designing solutions to complex waste problems.

Packaging Manufacturer, Composter Collaboration

SC Johnson, a fifth generation family company founded in 1886, supplies a multitude of well-known household brands that include Ziploc, Windex, Pledge, Glade, Raid, OFF and Scrubbing Bubbles. SC Johnson employs 13,000 people with operations in 70 countries.  Its corporate motto is: “We work every day to create winning products, ensure less waste, leave a smaller footprint and make life better for families.”
On a much smaller and regional scale, Cedar Grove Composting is also family owned and an internationally recognized leader in the organics recycling and compost manufacturing space. The roots of Cedar Grove go back to the 1930s, when the company founders established some of the first recycling programs in Seattle. Since starting its commercial composting operations in 1989, Cedar Grove has diverted over 7 million tons of yard trimmings and food waste from the landfill into compost.
With sustainability as a core value, SC Johnson is committed to helping reduce landfill waste. The company works to offer consumers the best “next life” options available, and is expanding its work in promoting the recycling and composting of its products. On the recycling front, over 18,000 retailers take back polyethylene (PE) bags and films in the U.S., including clean and dry, noncompostable PE Ziploc bags.

Samples of compostable Ziploc bags supplied to households in two Seattle neighborhoods.

Samples of compostable Ziploc bags supplied to households in two Seattle neighborhoods. Photo courtesy of SC Johnson

SC Johnson also has developed a product that offers consumers (with access to curbside commercial composting) a compostable option as well. Its fully compostable Ziploc sandwich/storage bag option meets ASTM D6400 standards, is BPI certified and has met Cedar Grove’s field test requirement for disintegration. By offering consumers better end of life options via composting, SC Johnson also plays a major role in minimizing food waste disposal, as partially eaten sandwiches, stale cereal or wilted snacks can go directly into curbside containers in the compostable Ziploc bag.
For packaging manufacturers to succeed in the compostables space, they must first develop formulations, substrates and products that meet recognized industry standards for compostability (ASTM D6400, BPI certification and/or Cedar Grove acceptance). From there, they must also create a compostable option that performs adequately for the public. Finally, once all the hurdles and challenges have been met (an often tedious and lengthy process), there is more to do to get the products into the intended permitted compost manufacturing sites.

Will It Pass The “Come Along” Test?

Just because a product technically disintegrates and breaks down into biomass and water in Cedar Grove’s composting piles, there are still other requirements and steps to complete before a product is accepted into its program via residential collection systems. Historically, the only food service items received into Cedar Grove’s residential streams have been compostable kitchen container liners, pizza boxes, uncoated paper plates, and napkins. Because compostables cannot be easily distinguished from noncompostables, even the most advanced composters with fully developed testing and approval systems are not willing to open themselves up to a full range of indistinguishable packaging, even if that packaging passes all compostability criteria. Why? Because of the “come along” or “copycat” factor that exists with a noncompostable “look alike.”
The general public is not always able to distinguish a PE item from one made of compostable bioplastics. For that reason, the additional requirement for Cedar Grove’s program is a distinctive color marking. This enables the public to distinguish compostable items from PE versions. At the composting facility, this is referred to as the “10 foot away” requirement, where the crew has the ability to distinguish the two from a distance. In the product development phase, SC Johnson had already taken this into account, making the Ziploc bags a familiar compostable “green” that is recognized within the urban composting system and matches the general shades of accepted compostable kitchen bucket liners.
With the color distinction addressed, SC Johnson moved to the next step in vetting the product to ensure the compostable Ziploc bag would not invite the improper sorting of the clear, noncompostable versions into the stream. The theory was that with the color distinction and prominent compostable markings, the new compostable Ziploc brand bags would theoretically be easily sorted as compostable. In considering acceptance of these items on a mass scale within the Seattle market, it was necessary to prove the theory prior to taking another step toward their acceptance.

Real-Time Testing

In the summer of 2013, Jeff Zettle, SC Johnson Home Storage Division Sustainability Manager, met with Cedar Grove’s advisory team, Susan Thoman and Michele Riggs. The collective team agreed that in order to address challenges Cedar Grove had in approving the new compostable Ziploc bag for residential acceptance, it needed to illustrate firsthand the reason for its issues and concerns. At Cedar Grove’s facility in Everett, Washington, the multitude of film plastics being screened out of the finished compost was clear to see. By the end of the site visit, all agreed that additional work was warranted to fully vet the product before acceptance into Cedar Grove’s composting system.
The companies met again at the US Composting Council Conference in Oakland, California in January 2014 to begin initiating a work plan. After intermittent correspondence, the project team agreed upon a study design and implementation plan funded by SC Johnson that would ultimately launch in late spring, 2014.
As companies, SC Johnson and Cedar Grove share many of the same goals and traits. Both are manufacturers striving to make good, quality products at the lowest possible cost, and both companies work on a grand scale to solve waste problems. Within that platform of shared values, the collaborative process began easily.

Study Scope

In consideration of the study design, it was important to define what information was needed from the results. From the project team’s perspective, the following questions needed to be answered:
Would the new storage bag confuse the public into thinking that any noncompostable plastic storage/sandwich bags could come in once the compostable version was introduced?
Does the color marking (green) of the product sufficiently distinguish it from polyethylene bags?
Would it actually lessen feedstock contamination as a clearly differentiated compostable option to polyethylene?
How would it travel between residential and commercial solid waste systems (specifically schools) and into commercial composting systems?

Study Design

To answer these questions, Cedar Grove and SC Johnson agreed to perform an operational and third party waste audit of both residential and commercially collected grade school samples within two different Seattle area neighborhoods. Sample areas were designed to track the product’s movement from a residential site to a commercial site via the grade school. Since most items used for food storage would leave the home as a portable snack or lunch, the expectation was that the compostable bags could be released to a sample of households, and then tracked through the organics portion of the solid waste system. After the product’s launch into the sample area, information gained from waste auditing would help determine if the compostable Ziploc bag actually invited more contamination into the stream through any potential confusion about the product category (both residentially and within a school lunch room program). Baseline audits were done prior to distribution of the compostable bags to assess the number of PE bags in the organics stream. All audits were done on loads brought directly to Cedar Grove’s tipping floor from the residential route or school.
Development of the study involved designing components related to Cedar Grove’s facility operations and commercial collection teams, along with third party residential haulers, waste audit specialists, municipalities, school districts, and residents within those selected sample areas. Schools were provided a sample of the bags they would see that could be accepted in food carts during the study. Costs and needs were developed for each phase of the study, and mapped out on a management worksheet. Overall study implementation, data gathering, and reporting were performed by a an independent third party contractor, with Cedar Grove assisting in the study design, operational coordination, and sample distribution to approximately 1200 households.
In addition, a plan was devised to get boxed products shipped directly to residents’ addresses within the sample areas. Finally, a customer survey option was included with the product sample literature to provide SC Johnson with feedback from consumers on the product’s performance and their opinions about the product.

Results and Next Steps

The project duration took place over a 9-month period, with third party data and results reviewed and finalized in January 2015. Upon completion of this phase of the project teams’ ongoing work, results proved favorable to SC Johnson and Cedar Grove. In the short term study, the introduction of distinctively and similarly colored sandwich bags (resembling the color of compostable kitchen bucket liners) did not increase or invite noncompostable bags into the stream. In fact, in one sample’s post audit review, there was a decrease in PE storage/sandwich contamination in both the residential and school audited samples. As a result of this preliminary work, Cedar Grove has authorized acceptance of the compostable Ziploc bag residentially, with a caveat that requires periodic studies and monitoring over time to ensure there is no long term adverse effect on feedstock.
In addition to the outcome gathered from the audit samples, consumer responses regarding the product were overwhelmingly positive. Most were delighted to know the product existed and wanted to know when and where they would be on the market. In addition to the exceptional quality and performance marks for the product, the highest ranked value residents noted was its compostability within the curbside collection and composting system.
By working together responsibly with thoughtful methodologies and realistic time frames, it is possible for composters and product manufacturers to forge new relationships to find solutions to both waste and contamination problems. To do this, composters and product developers work best in a “manufacturer to manufacturer” collaboration model that is based on mutual respect and a platform of common goals. Designing models around products, how they are used and how they travel through solid waste systems is important to understanding the impacts of a growing universe of compostable alternatives being embraced by consumers and companies. Thoughtful product launches and continuing research that provides facts and information to both composters and compostable product manufacturers will continue to better inform both manufacturing worlds of the real and ultimate benefits and potential drawbacks (and solutions) of compostable product alternatives.
Susan Thoman is Vice President of Corporate Development at Cedar Grove Systems. Jeff Zettle is Home Storage Sustainability Manager at SC Johnson.

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