The Annelund waste treatment plant in Enköping needs to reduce the PFAS levels in the water and an investigation is now underway to determine the appropriate treatment technology. One challenge is the high level of the short-chain PFAS variant PFBS. Chromafora’s SELPAXT technology, whose strength is to capture short PFAS, is now being tested.

At the Annelund waste facility in Enköping, Vafabmiljö Kommunalförbund operates a landfill. Water from the landfill and the operational areas is currently sent to the municipal wastewater network for treatment, but for some time now VafabMiljö has been running a project to build a new treatment plant at Annelund to be able to lead the water to a surface water recipient instead.

New treatment plant in operation in two years
The main focus of the new treatment plant is to reduce the PFAS levels in the water. Linus Fogelberg, environmental investigator at VafabMiljö, is responsible for the project and has for some time been investigating a number of different treatment technologies through pilot tests at the plant:

“We want to test several different technologies to see which one is most suitable for Annelund’s water. What is considered most suitable for a new full-scale treatment plant will be a combination of the investment cost being economically reasonable, the treatment results being environmentally acceptable and the technology being technically feasible. It’s a tight schedule, and the goal is to have a new treatment plant in operation within two years,” he says.

Linus Fogelberg, environmental investigator at VafabMiljö

PFAS, a common problem for the entire waste industry
PFAS has been found in water at virtually all waste facilities in Sweden, making it a common ”headache” for the entire waste industry. The major challenge is that PFAS is not one compound but several thousand different individual substances and that treatment technologies work differently well on different PFAS compounds. Another challenge is that the assessment criteria for PFAS in water have changed in recent years from mainly applying to PFOS and change is still ongoing through new proposals for surface water criteria linked to PFAS. According to Linus, this means that the main problem with PFAS is a common denominator for the waste industry.

“Knowledge is increasing and when it comes to the treatment of PFAS with long carbon chains, we know quite a lot, but with short-chain PFAS compounds it is trickier,” he says.

A combination of different treatment methods may be needed
At Annelund’s waste station, VafabMiljö is testing and evaluating several different methods for removing PFAS from the water: activated carbon, ion exchange and Chromafora’s SELPAXT technology.

‘Here at the waste plant in Enköping, the PFAS content of the water is dominated by a specific short-chain PFAS: PFBS. In light of this, Chromafora’s SELPAXT technology was interesting to test. “In the end, it may also be that in the full-scale plant we need to use several different purification methods together,” says Linus.

The test run of SELPAXT on a partial flow of the collected water from Annelund began in March and will end in May. After that, the tests will be compiled, reported, evaluated and cost estimated to form the basis for how we proceed in the project.