Tuesday, September 10, 2024
2:00 PM - 2:30 PM
Location Name
The Next Level: Considering On-site reactivation for GAC exhausted with PFAS
Other/Special Topics

As utilities around the country grapple with PFAS challenges, a slightly longer-term challenge includes understanding how to manage costs, availability, and liability associated with GAC replacement and disposal. For larger surface water facilities, for whom GAC is often the most viable long-term solution for PFAS, DBPs, and many additional known or unknown future contaminants of concern, the cost of GAC replacement or reactivation can be overwhelming. As a result, several utilities around the country are evaluating the potential for on-site GAC reactivation capacity to more effectively manage costs, mitigate potential liability associated with PFAS impacted residuals disposal, ride out potential supply chain challenges, and control GAC their supply more effectively. Thinking beyond their own requirements, in some situations it may make sense to consider GAC reactivation as a revenue generation service, either as a for-profit venture led by a single utility, or as a partnership among regional partners to pool risk and maximize efficiency. There is considerable interest in GAC reactivation as a potential PFAS destruction approach for closing the loop on spent GAC with previous studies from GAC vendors demonstrating PFAS destruction in select reactivation kiln designs. Although there are many obstacles yet to overcome with the concept, including unfamiliar regulatory compliance (air quality and solid waste handling) and liability challenges associated with handling and transport of potentially hazardous waste, one of the first considerations is defining the available market and required capital investments and long-term O&M associated with the on-site GAC reactivation. Hazen has recently begun exploring the feasibility of on-site GAC reactivation with several clients. Utilizing successful installations of on-site regeneration as examples, we explored available technologies for municipal carbon reactivation and developed costs and conceptual designs for two case studies – one very large surface water facility who would implement GAC reactivation to service a single facility, and another for a series of nearby water facilities, considering the benefits of regional reactivation facility. The presentation will focus on general considerations associated with the viability of developing an on-site reactivation facility for several purposes (single facility implementation, regional collaboration, or for-profit reactivation), along with case study results from preliminary feasibility assessments. Results from adsorption cost modeling will inform how the elasticity of GAC reactivation cost may impact the overall adsorbent changeout costs for utilities considering GAC installations.