PFAS separation-concentration system introduced in North America – Chemical Engineering

By Scott Jenkins |

A technology originally developed in Australia by OPEC Systems (Emu Plains, NSW, Australia; www.opecsystems.com) to separate and concentrate per- and polyfluoroalkyl substances (PFAS) in a range of water applications has now been introduced in North America.

The technology, known as surfactant foam fractionation (SAFF), is an environmentally sustainable separation method capable of removing >99.8% of regulated PFAS compounds from water, according to Allonnia (Boston, Mass.; www .allonia.com), the company that distributes the technology in North America.

PFAS compounds greater than C6 are amphiphilic, with a hydrophilic head and a hydrophobic tail. SAFF takes advantage of this property by bubbling air through PFAS-containing water so that the PFAS molecules accumulate at the air-water interface. The water to be decontaminated enters a series of reactors in which the air bubbles and the PFAS is entrained with the bubbles. The key parameters for effective separation are the dynamics of the tank configuration, the size of the air bubbles and the rate of air introduction, explains Nicole Richards, CEO of Allonnia.

Typical levels of PFAS contaminants in water samples can range from 200 to 50,000 parts per trillion (ppt) or more, and the SAFF concentrator can reduce PFAS levels to a few parts per trillion, Richards notes.

SAFF treatment units are mounted on mobile trailers and can be used temporarily at sites to remove PFAS from groundwater, landfill leachate, process water and other water sources, says Richards. SAFF units are designed to be coupled with PFAS destruction technology, such as “PFAS destruction using supercritical water”, Chem. Eng., March 2022, p. 8.

SAFF technology works with all PFAS molecules with six or more carbon atoms, but is not as effective for short-chain PFAS compounds. Allonnia is therefore working on adding a bio-surfactant to the SAFF system to capture the shorter chains.