BioCycle Magazine

ABC Digestate Standard Testing And Certification Program


The American Biogas Council launches its digestate standard initiative this fall. Benefits and “how-tos” of program participation are focus of ABC’s Workshop at BioCycle REFOR16.

What is digestate, how do you describe it to regulators or market it to customers? That’s the critical digestate knowledge gap addressed by the American Biogas Council‘s (ABC) Digestate Standard Testing and Certification Program (Program). The final version will be unveiled at the ABC workshop on Monday, October 17, leading into BioCycle REFOR 2016 in Orlando.

Once organic material has been processed in an anaerobic digestion system, the liquid and/or solid products that exit the system are called raw or whole digestate. These products have been physically and chemically changed, acquiring desirable qualities that make it more valuable when beneficially used. The ABC Digestate Standard Testing and Certification Program is a voluntary, industry-led specification that sets forth the testing methods and quality management system for characterizing these products. The Program quantifies the beneficial physical and chemical changes resulting from the digestion process, and delineates the physical and agronomic properties of the digestate products.

Program Origins

Development of the Program began in 2014 when several ABC member companies encountered both market and regulatory barriers to selling digestate. These barriers were created by unfamiliarity with digestate as a product and the absence of standard analytical methods for determining its agronomic value and safety. The ABC recognized that lack of consistent regulation and understanding of the beneficial properties of digestate produced from the processing of non-sewage derived organics (such as household organic waste) prevented digestate from finding its target markets.

Project lenders viewed digestate as a liability rather than the revenue-generating product that project developers know it can and should be. To encourage investment in biogas projects and grow the industry, the ABC recognized that the “digestate knowledge gap” needed to be addressed; thus work on the Program began in earnest.

The Program was formulated with broad stakeholder input by the ABC Co-Products Working Group. The undertaking included three workshops, and more than 50 conference calls and web meetings. The resulting product reflects integration of digestate standards programs in other countries, and relevant portions of existing U.S. Environmental Protection Agency regulations. What ultimately materialized are standardized terminology, testing procedures, and technical data sheets to characterize digestate. This allows digestate’s composition and beneficial use to be accurately represented by biogas project owners and understood and accepted by regulators and customers.

The ABC Co-Products Working Group benefitted tremendously from the participation of so many key stakeholders in this process, note its Co-Chairs, Amy McCrae Kessler and Clarke Pauley: “It was vital to understand the concerns of operators, regulators, farms, consumers and composters receiving digestate to ensure that our Program includes meaningful testing parameters that highlight the agronomic and economic value of digestate and address health and safety concerns.”

Standardized Test Methods

Using prescribed standardized test methods performed by laboratories to be certified under ABC’s Digestate Lab Certification Program, test results and accompanying operational information will quantify the beneficial physical and chemical changes resulting from the digestion process, and delineate the physical and agronomic properties of the digestate products. This information includes: Input materials; Physical characteristic of concern and importance; Chemical characteristics of concern and importance; Agronomic properties; and Potential restrictions on use.

”In order for end users to decide whether or not they want to accept digestate, they need to know what feedstocks were used and enough about the physical characteristics of the digestate to know how these products can be used safely and effectively,” explains Pauley. “Digestate produced from green waste and food waste is widely used in Europe as a drop-in replacement for conventional compost and fertilizers. It is our hope that this ABC digestate standard will provide some additional surety to end users to buy these products with confidence.”

As drafting of the Standard concludes, ABC’s focus shifts to finalizing procedures for lab certification and plans to accept applications in Fall 2016. The Council also will create the Program rules, which will include use of the new logo, required testing frequency and fees. “We are working hard to ensure there is more benefit than cost for the digestate producers,” states Patrick Serfass, ABC Executive Director. “We believe that we created a program that strikes the right balance between providing credible, specific information at the right frequency, and avoiding excessive documentation and reporting requirements that are inappropriate for biogas plants not regulated under the EPA’s Part 503, 40CFR biosolids rule.”

By participating in the Program, biogas plant operators will benefit from having the necessary information to ensuring land application of digestate is in compliance with nutrient management plans. The test results will also help communities and regulators by showing credible reductions in pathogen levels and odor generation.

Read the full article in BioCycle Magazine

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