What is a PFAS treatability study?
A treatability study is a customized examination conducted to address a specific question related to environmental remediation for a client. It begins with problem identification and progresses toward the development of practical and scalable solutions.
Treatability studies can employ various testing methods, ranging from simple batch tests to more sophisticated column tests or other bench-scale tools.
What are the crucial elements of a well-designed study?
- Shared understanding of the study goals for treatment and regulatory compliance
- Assessment of available technologies to efficiently manage both technical efficacy and economic feasibility
- Accounting for fundamental mechanisms related to PFAS transport and phase behavior
- Suitable laboratory conditions to provide comprehensive insights
Appropriate testing conditions in the laboratory to simulate real-world scenarios
What are rapid small scale column tests (RSSCTs)?
Rapid small-scale column tests speed up the evaluation of sorbent materials for PFAS treatment. These tests use granular activated carbon (GAC) for grinding sorbent particles to achieve better mass transfer that enables a higher flow rate of water through the media. This shortens the treatment time from years to just a couple of weeks.
Moreover, rapid small-scale column tests offer flexibility by allowing simultaneous testing of multiple sorbents and conditions. This includes understanding the impact of pretreatment measures, such as removing iron or total organic carbon (TOC), under controlled laboratory conditions. They enhance the effectiveness of PFAS treatment strategies by enabling researchers to achieve better decision-making in the initial phases.
These tests validate the applicability of various sorbents, including GAC, ion exchange resins, and novel materials, for PFAS removal in groundwater and drinking water systems, thereby contributing to the strategy-making process for clients. Their effectiveness allows the researchers to confidently recommend them for further evaluation at pilot or full scale.
Rapid small-scale column tests enhance the effectiveness of PFAS treatment strategies by enabling researchers to achieve better decision-making in the initial phases.
Charles Schaefer
What factors impact the selection of technology for PFAS removal?
- Range of PFAS types (hydrophobicity, surface activity)
- Compatibility with different matrices (drinking water, groundwater, landfills)
- Matrix components in water, solids, or biosolids affecting treatment technologies
- The effect of matrix components in water, solids and biosolids
- Space or size restrictions with the client facilities
- Client’s budget allocation (capital vs. operating cost)
Client-specific needs and constraints
How do we develop a customized strategy to address PFAS treatment specific to a client's needs and circumstances?
The process of creating a strategy for the PFAS treatment selection process can be iterative. It can involve multiple phases of investigation and testing.
The first step is a desktop study to collect information and narrow down the potential treatment options. Following this, to further refine the process, simple screening tests are performed on the batch scales.
For better accuracy, more comprehensive tests such as larger batch scale or column tests may be conducted in the lab. All these tests are conducted while considering the cost and infrastructure constraints of the client to select the most effective strategy that can address PFAS contamination.
