Modeling Challenges for a Proposed Agricultural Processing Plant A Case Study

摘要

This is a case study about a proposed agricultural manufacturing and processing plant. The proposed plant has various onsite emission units such as dryers, boilers, particulate sources, and sources of volatile organic compounds. The subject of this case study is the demonstration of compliance with the stringent PSD increments for particulate matter. The demonstration was driven by a permit-to-install application for plant construction. Historically, modeling techniques and practices were often conservative; that is, they considered the combined effects of "worst case" parameters and variables such as emissions estimates and meteorology. Simplifying and conservative modeling techniques are no longer appropriate for demonstrating compliance with stringent standards. Air permitting programs typically have an air modeling component and they rely on EPA models and guidance to achieve this. Air modeling assesses air impacts for federal, regional, state and local permitting. Applications for air permits require the use of model methodologies that continue to evolve as more data is collected and the science improves. Notwithstanding, EPA uses its existing models to support its regulatory programs, which can be problematic for an applicant if that applicant is modeling its plant to obtain a new permit or is being evaluated as part of a SIP.