1174152 - Permitting Challenges for Wastewater Treatment Plants in California

In September 2016, Senate Bill (SB) 1383 was signed into law in California, establishing methane emissions reduction targets in a statewide effort to reduce emissions of short-lived climate pollutants (SLCP) and achieve a target of 75% reduction in the level of the statewide disposal of organic waste by 2025. This law has had a significant impact on wastewater treatment plants (WWTPs) in California, where the water sanitation districts must find ways to reduce organic wastes, including biosolids produced from wastewater treatment, that have historically been sent to landfills. As a result of this law and other regulatory programs adopted in recent years, many of the WWTPs in California are looking at major upgrades to their facilities, including improvements in digesters and aeration basins and related odor control systems, as well as the introduction of combined heat and power (CHP) engines fueled on digester or biogas, and in some cases biosolids. Due to California’s stringent air quality new source review (NSR) programs, these facility modifications and new equipment require permitting by the local air district, such as the Bay Area Air Quality Management District (BAAQMD).
Coincident to these efforts to improve operations and reduce waste, local air districts have been implementing programs to reduce air pollutants, and in the case of some air districts such as the BAAQMD, to also reduce GHG emissions. The increasing scrutiny by air districts combined with the need for site improvements has led to many permitting challenges for these facilities. For example, although each of California’s 35 air districts is a little different, in the past air districts commonly used the Joint Emissions Inventory Program (JEIP) emission factors, based on a study completed in 1993 which relied on source testing, for WWTP facility-wide emissions calculations. Now air districts are considering emissions from individual process units (e.g., aeration basins, grit separators, digesters, headworks), considering a wider array of toxics, requiring more monitoring, etc. Calculating net emissions increases for individual process units when the baseline emissions are facility-wide presents a difficult challenge. The lack of emission factors for toxic air contaminants to determine health risks from new CHP engines, flares, and dryers for the biosolids also is problematic. This presentation will discuss these, and other permitting challenges Yorke staff have encountered in over a dozen recent permitting projects for WWTPs in California.