Larrissa Smith to present at the World of Coal Ash 2024

Larissa Smith (Ontario) will present “Natural Attenuation of Metals and Inorganics: Insights from Laboratory Testing” at the World of Coal Ash (WOCA) 2024 on Wednesday, May 15, 2024, at 11:00 a.m. EDT at the Amway Grand Plaza in Grand Rapids, Michigan. Her coauthors are Michael Healey (Ontario), Kela Ashworth (Ontario), Jacques Smith, PhD (Tennessee), and Jeff Roberts (Ontario).

Larissa Smith is a Scientist in the treatability division of SiREM. She has more than 10 years of experience in treatability services and studies, and in other testing fields.

WOCA is the leading international conference on the science, application, and sustainability of coal combustion products (CCPs). The conference is organized by the American Coal Ash Association (ACAA) and the University of Kentucky Center for Applied Energy Research (CAER).

The ACAA supports the development, implementation, and continuation of effective programs for the management and use of CCPs. The organization advances the management and use of CCPs in ways that are environmentally responsible, technically sound, commercially competitive, and supportive of a sustainable global community.

The University of Kentucky’s CAER investigates energy technologies to improve the environment and contribute to fossil and renewable energy policies by addressing topics including CCPs, biofuels and clean fuels, materials technologies, organic electronics, and power generation.


Laboratory treatability studies can be used to evaluate and optimize groundwater treatment options for contaminants of concern found at coal combustion residual (CCR) sites. An important consideration in groundwater treatment selection is the suitability of monitored natural attenuation (MNA) as a treatment component or as a stand-alone passive treatment. This presentation will focus on the use of treatability testing to evaluate natural and enhanced attenuation treatment options for redox-sensitive metals in CCR-impacted groundwater

In one demonstration, a comprehensive laboratory program was performed based upon the United States Environmental Protection Agency’s tiered approach to identify the natural attenuation processes, rates, attenuation capacities, and longevity of arsenic-, lithium-, sulfate-, and boron-impacted groundwater from a CCR impoundment site. Laboratory testing was used to develop site-specific sorption coefficients and demonstrate that, after sorption, potential desorption back into groundwater would not be affected by changing redox conditions. The data was also used to provide insight into the attenuation mechanisms. These findings helped to support MNA as part of the corrective action plan submitted to the regulator. In a second demonstration, zero-valent iron was used to sorb arsenic from groundwater. The results from the treatability study were used to support the feasibility assessment for the site.

More Information

About the event: WOCA 2024



For consultation regarding laboratory treatability testing of metals and inorganics, as well as monitored natural attenuation as a remediation option, contact Larissa Smith at

Learn more about Larissa Smith: Larissa Smith | LinkedIn