Seattle, WA | tim@compostsystems.com

Tim is founder and president of ECS and has worked in compost industry for 30 years.  Under his leadership ECS has provided engineering and/or process technology to 100’s of large-scale composting facilities.  He is active in compost process science and compost air emissions research. Tim serves as a Trustee for the Compost Council’s Research and Education Foundation and regularly teaches workshops on facility design, process optimization and odor management.  His professional passion is combining science-based inquiry, professional engineering and operational experience to help our industry improve.

Session Code: 1E

Track: Advocacy/Policy

Session Name: Permitting-Experiences Around the States

Session Time: Wednesday, February 7, 8:15 – 9:45 AM

Presentation Title: Compost Facility Air Permiting

Presentation Description: The number of jurisdictions in the US requiring air permits to build or modify composting facilities is growing, as are the complications associated with obtaining those permits. What started out as a simpler requirement only found in a few non-attainment air quality management districts in California has now grown in complexity and spread to states and regions that comply with the EPA’s National Ambient Air Quality Standards (NAAQS). Regional EPA regulators, and therefore local regional regulators, are taking a closer look at how emissions from large composting facilities may trigger a Title V designation under the Clean Air Act. This trend is adding cost, delays and uncertainty to the development of new composting capacity needed to match the growing mandate to sustainably recycle organic waste. Fortunately, there are some proactive steps facility developers can take to mitigate these downsides. There is also movement on the regulatory front to improve and standardize the scientific basis behind the implementation of these regulations that will hopefully simplify the permitting process.

This presentation will start with a brief history of air permitting compost facilities. We will then outline the key tenants of the Clean Air act as it applies to composting and how different jurisdictions interpret and enforce them. We’ll provide several recent examples of ultimately successful permitting efforts to highlight process steps and possible pitfalls and counter measures. Lastly, we’ll summarize an approach to permitting based on peer-reviewed compost science and data from certified source tests that will help developers and regulators work together to protect our environment and responsibly grow the US composting industry.

Session Code: 2C

Track: CREF Research

Session Name: Update on microplastic degradation, remote sensing of compostable packaging, and PFAS

Session Time: Wednesday, February 7, 1:45 – 3:15 PM

Presentation Title: Optimizing Compost Process Conditions to Accelerate Bioplastic Degradation

Presentation Description: As food scraps are increasingly diverted from the solid waste stream, feedstocks delivered to commercial-scale composting facilities are receiving increased amounts of biodegradable plastics. Many of these plastics are labeled “compostable” and bear various certifications (ASTM D6400 & D6868 for example) that indicate they conform with technical requirements of this label. Unfortunately, many compost facility operators report that theses plastics do not adequately degrade their normal processes and retention times. The result is that a significant proportion of compostable products are either screened out along with other contaminates or remain as visual contaminates in their products and overs, or end up along fence lines.

In researching this issue, we found a lack of quantitative guidance that would inform operators how they might manipulate compost process conditions to reduce the time required to adequately biodegrade these polymers. A material that is “biodegradable” is, by definition, degradable by the action of microorganisms. The research shows that the efficacy of these microorganisms is strongly influenced by process conditions. Our findings begin to correlate rates of biodegradation of certified compostable bioplastics with realistic and achievable compost process conditions.

We chose a series of common certified Polylactic acid (PLA) serviceware and bags and exposed them over various retention times to well-controlled composting conditions in 12-liter bench-top reactors. The control parameters included directly controlled retention time, temperature, moisture content, and air flow rate; and indirectly controlled oxygen levels, pH, and rates of substrate bio-oxidation. Our substrate mixes included various ratios of green waste, food waste and ground wood. Retention times were varied from 2 to 6 weeks to represent active phase composting in an aerated system. DeTBA on the PLA item, degradation was assessed by different combinations of strength loss, weight loss, and visual analysis. We were able to correlate various combinations process conditions and retention time with PLA degradation. The data we generated offers initial guidance for optimizing compost processing to better manage PLA materials. It also provides targets for PLA manufacturers to improve their products to better facilitate compost operations.