Remtech's bench-scale treatability tests can provide engineering information including carbon mass, flowrates/sf, the number and size of GAC and/or multi media columns, and media contact times, for the design of full-scale systems.
Remtech's mobile multi-media treatment system was designed based on bench-scale activated carbon tests were run on heavily contaminated runoff water from a chemical plant fire extinguished with AFFF foam. Treatment performance samples were run by an independant testing lab. Untreated total PFAS concentrations of 2.55 mg/l (2,550,000 ppt) (Table 1) resulted in PFAS removal efficiencies listed in Table 2 for the six (6) of the seven (7) twenty-three (23) EPA proposed PFAS regulated analytes (listed in RED). Six of the PFAS analytes were Below Detection Limits (BDL) with ng/l sensitivities. Analyte removal efficiencies for TSS, COD, TOC, and VOCs exceeded 94.45%.
Wastewater PFAS influent and effluent concentrations are typically in the range of 50 to 200 ppt, landfill leachates 4,000 ppt, and drinking water 20 ppt. Higher concentrations of PFAS occur near industrial discharges. Other organic loadings including VOCs, Oil & Grease, TOC (Total Organic Carbon), COD (Chemical Oxygen Demand) and other analytes need to be removed prior to removing PFAS analytes. PFAS removal efficiencies increased when carbon contact times were increased from 10 to 20 minutes.
The bench-scale treatment train consisted of concentration equalization of wastewater from over 20 frac tanks, clarification, aeration, sand filtration, and three (3) granular activated carbon filters in series. Coal based virgin GAC specifically designed for PFAS removal was selected. A significant finding was that 28.65% of PFAS was removed by aeration.