The New and Improved BASTE Model for Estimating Odors and VOC Emissions

The Bay Area Sewage Toxics Emissions (BASTE) model is a benchmarking tool for estimating emissions of volatile organic compounds (VOCs) and other compounds from liquid wastewater processes. This poster will describe the process undertaken to update the BASTE model to make it a more powerful and user-friendly tool for estimating odors and VOC emissions.BASTE is a computational model that estimates pathway losses (volatilization, sorption, biodegradation) from wastewater for “strings” of processes that make up treatment trains. It allows analyses of complex treatment configurations including split flows, liquid streams, quiescent surfaces, drops, weirs, packed media, aerated processes, biological processes, and covered processes.The model was originally developed in 1990, and upgrades to model performance were added in the early 1990's. In 2002, it became apparent that the model's format was severely outdated and its capabilities needed to be expanded to accommodate new desired uses. Two categories of upgrades were made–model usability and capability. Usability upgrades focused on technology improvements and data management, enabling the user to work in a familiar Windows-based environment and export model output to Excel for further data management. Capability upgrades concentrated on expanding the uses of the model, allowing for estimation of additional compounds, accounting for wastewater processes not previously modeled, and improving estimation algorithms. Augmenting the model's odor estimation capability was a high priority, as many wastewater agencies are looking to improve odor control at their facilities.In addition to making the model considerably more efficient and understandable, these upgrades have many practical benefits to the POTW community. The model is now considerably easier to update if process or equipment changes are made at the plant or if additional data is made available. With its simpler interface, model owners can now modify and run the model themselves, without having to hire consultants. Improved interface and export capability also make it feasible to run multiple scenarios to make predictions about emissions as plant modifications are considered. Additional algorithms allow for more accurate modeling of a variety of wastewater systems. Finally, the new capability to conduct odor emissions assessments and evaluate viable control technologies can assist agencies in considering their options for odor control.The BASTE upgrade project was initiated in November 2002. Upgrades will be completed in the fall of 2003, with copies of the model available for use by wastewater agencies in the winter.