Activated carbons for drinking water treatment in times of crisis (AK-Crisis resilience)

Large-Scale AC-Filter, Waterwork

In 2022, there were supply bottlenecks for activated carbons. This project was funded by the DVGW in order to determine how to respond to such crises.

The adsorption properties of the activated carbons vary depending on the raw material. Therefore, if one type of activated carbon is no longer available, it is not generally possible to switch to another. How to react in individual cases when replacing the activated carbon, was compiled in the research project.

Alternatives to activated carbons based on the raw materials coal and coconut shells are, in principle, activated carbons based on lignite and wood. Further investigations are required for a final evaluation of these activated carbons.

No activated carbons for drinking water treatment are currently produced in Europe, but approaches are being pursued for activated carbons based on fruit stones. To date, biochar can only be used as powdered activated carbon, although here too, production is not yet taking place on an industrial scale. Further newl adsorbents for drinking water treatment are not yet foreseeable.

The availability of activated carbons based on bituminous coal as a raw material is expected to decrease, particularly due to the use of such products in the 4th purification stage at sewage treatment plants. The competitive situation could be alleviated by prioritizing high-quality activated carbons for drinking water treatment and direct activates and pool carbons for wastewater treatment.

In connection with the resilient use of activated carbon, a first step is to evaluate measures for minimizing the amount of activated carbon, as compiled in the report. This also includes the possibility of reactivation.

According to TZW and IWW experience and the expert workshop held, the introduction of PFAS limit values will increase the demand for activated carbon. In principle, alternative processes for PFAS removal are membrane processes (reverse osmosis and nanofiltration) and ion exchange. Prior to large-scale implementation, fundamental issues are currently being evaluated and waste disposal options are being examined.