(245c) Evaluating Process Costs and Performance Metrics of Granular Activated Carbon for the Removal of Pfas Under Model Uncertainty

After longstanding emissions of per- and polyfluoroalkyl substances (PFAS), concentrated efforts to implement systems for the removal of these harmful compounds are growing throughout the United States (U.S. Department of Energy, 2022). Granular activated carbon (GAC) adsorption has been demonstrated to be generally effective for the removal of PFAS (Verma et al., 2021). However, the estimated performance and cost of the system are not well understood at the design phase due to the infancy of the application of PFAS removal processes and lack of accurate and validated models.

Bench- and pilot-scale data characterizing PFAS adsorption onto GAC are available in limited quantities for a range of real and idealized feed water compositions (Hwang et al., 2021). However, breakthrough profiles as a function of absorbent properties, PFAS concentrations, background component concentrations, and column designs are unavailable. Under these limitations, the mass transfer mechanisms by which PFAS adsorb onto GAC and other factors that inhibit it are unknown, making it challenging to develop predictive models for PFAS adsorption.

The first objective of this work is to use a simplified GAC model to estimate the performance of PFAS adsorption onto GAC. WaterTAP, a framework for simulating water treatment processes, was used as a simulation platform for this purpose with integrated supplemental tools (Beattie et al., 2021). The constant pattern homogeneous surface diffusion model (CPHSDM) for GAC adsorption was used to predict PFAS removal (Hand et al., 1984). Adsorption isotherm and diffusion coefficient parameters were regressed to fit available data to describe the removal performance. The complexities of the true adsorption mechanisms and how they affect performance may be captured through the variability of regressed model parameters across diverse experimental data sets. Results of this work provide a distribution of the parameters to describe the uncertainty of the model.

The second objective is to evaluate cost and other performance metrics (such as system size and energy consumption) across the distribution of model parameters. This analysis was used to describe low- and high-end system costs and provide trends of the metrics that are codependent on model parameters. Cost mapping for variations in case-specific aspects such as water quality (captured by uncertainty in model parameters) and system size (captured by simulation of varying designs) gives an informed approximation of system performance and design for PFAS removal by GAC.

References:

Beattie, K., Gunter, D., Ben, K., Lee, A., Ladshaw, A., Drouven, M., Bartholomew, T., Bi, X., Bianchi, L., Arnold, T., Atia, A., Wang, C., Miara, A., Sitterley, K., Srikanth, A., Dudchenko, A., Amusat, O., Kinshuk, P., & Young, E. (2021). WaterTAP (v1.0.0). Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV, and Albany, OR (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States). https://www.osti.gov//servlets/purl/1785311

Hand, D. W., Crittenden, J. C., & Thacker, W. E. (1984). Simplified Models for Design of Fixed‐Bed Adsorption Systems. Journal of Environmental Engineering, 110(2), Article 2. https://doi.org/10.1061/(ASCE)0733-9372(1984)110:2(440)

Hwang, M., Grieco, S., Chang, J., Wille, A., Lozier, J., Plumlee, M., Pannu, M., Medina, R., Pham, C., Safarik, J., Huang, A., Dadakis, J., & Olsen, C. (2021). PFAS Treatment Testing Study (No. PPS0219211302SCO). https://www.ocwd.com/wp-content/uploads/ocwd_pfas_treatment_testing_stud...

U.S. Department of Energy. (2022). PFAS Strategic Roadmap: DOE Commitments to Action 2022-2025. U.S. Department of Energy.

Verma, S., Varma, R. S., & Nadagouda, M. N. (2021). Remediation and mineralization processes for per- and polyfluoroalkyl substances (PFAS) in water: A review. Science of The Total Environment, 794, 148987. https://doi.org/10.1016/j.scitotenv.2021.148987

Disclaimer:

This project was funded by the United States Department of Energy, National Energy Technology Laboratory, in part, through a site support contract. Neither the United States Government nor any agency thereof, nor any of their employees, nor the support contractor, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.