Types of Tests
Three principal methods to be used in evaluating sorbent performance are:
- batch tests,
- rapid-scale small column tests (RSSCTs), and
- pilot tests.
In batch tests, sorbents are mixed with water containing PFAS over a set amount of time. Contaminant removal is assessed from the comparison of initial and final PFAS concentrations in solution. Batch tests last from hours to a few days. In RSSCTs, small columns (i.e., cylinders) are packed with granular sorbent and PFAS-containing water is passed through the column. RSSCTs use small quantities of sorbents and water compared to how much is needed at pilot or full scale. RSSCTs accelerate the time needed to obtain data from months or years in pilot- and full-scale systems to days or weeks in the laboratory.
Pilot-scale tests are similar to RSSCTs but are performed with substantially larger columns that mimic full-scale operation. Pilot-scale tests are performed in the field and provide the most accurate prediction of sorbent performance at full scale. These tests last from months to over a year.