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17 September 2014

Tips on obtaining clean air permits for anaerobic digestion facilities


I’ve recently been deeply involved in permitting efforts for several dry anaerobic digestion (AD) facilities for Zero Waste Energy, LLC (ZWE). I would say that after preparing four permits in California (and successfully obtaining all four) and going after one more permit in Alabama, I have gotten a real window into what regulators are looking for in permitting these facilities. I thought my fellow air quality professionals might find it helpful to learn about challenges that we faced during the permitting process, what to expect when applying for air permits for similar facilities, and how to compile a successful application based on lessons learned from permitting AD facilities in a variety of air districts.

ZWE has two patented dry AD systems that process organic green waste and food waste to create useful biogas. Both systems are renowned for being cost effective and productive units. However, many air districts have little to no experience permitting such innovative equipment or processes. What helped us, and what I would recommend for others, is to provide additional education for the permitting agencies on the new technologies in the initial submittal stages. I think you’ll find it really benefits an applicant to proactively provide information and education to the permitting agencies to show transparency and to address the benefits of the reduced emissions resulting from these technologies.

For all five ZWE projects there have been different responses and requests to the initial submittal of the air permit applications, even with the same ZWE AD technologies being proposed. Although additional efforts are needed to further explain the systems, the ZWE facility air permitting was simplified due to state of the art emission abatement devices. Figure 1 shows the Zero Waste Energy San Jose Project.

Figure 1 - Zero Waste Energy San Jose Project

Figure 1 – Zero Waste Energy San Jose Project

Showing benefits is one key to successful applications

The organic materials used in the digesters are diverted from landfills and used to create a beneficial end-use biogas; the key to all of these facilities is that there are limited emissions created depending on the type of equipment to which the biogas is routed. All of the facilities are producing combined heat and power (CHP) and/or compressed natural gas (CNG), and therefore are sustainable facilities. Additionally, with a specific combination of equipment and processes, a facility can be carbon negative. Another advantage is that the majority of solid bi-products from the AD process are frequently placed into composting facilities to create an additional beneficial use product.

Predict information requests and proactively provide data

Although each AD system is unique in the amount of material it can process and technologies used for processing, there is a general flow of materials and gas through all of the facilities. Figure 2 below details the flow of solid materials (outlined in black) and the flow of gas (outlined in gray) that exists, independent of the type of facility.

Figure 2 - Flow of solid materials and gas
Figure 2 – Flow of solid materials and gas

We worked closely with ZWE to incorporate information from the data that regulators reviewing previous applications had requested into the more recent ZWE facility applications. In this way, we built on what we knew would be required and worked to streamline the permit application process for future facilities. We also took advantage of any opportunities to attend pre-application meetings, finding that doing so really helped foster clear and fluid communication throughout the permitting process. Not all air districts allow pre-application meetings, but if yours does, I highly recommend requesting one. We also made sure that we would be available for multiple conference calls and/or meetings with the air district following application submissions and initiation of operation for all facilities.

Do you think air districts should be educated on these new and innovative technologies before they are receiving applications for operations?

Maria Bowen is an Environmental Specialist who has assisted in air permitting efforts at Cornerstone for the past three years.






Categories: Air Quality, Alternative Energy, Biogas and Landfill Gas, Environmental Planning & Compliance, Organics
Posted By Maria Bowen at 12:17 PM  |  No Comments on Tips on obtaining clean air permits for anaerobic digestion facilities

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