The Challenge: Forever Chemicals

PFAS (per- and polyfluoroalkyl substances) are characterized by extreme stability. The problem: They do not simply bind to conventional soil but are highly mobile and migrate directly into groundwater when it rains. In practice, this makes contaminated soil a "wandering hazardous waste".

Stehr, holder of over 100 patents, has taken on this enormous challenge and developed a pioneering system to solve the problem: mixing in activated carbon to immobilize contaminated soils.

The PEFAS system is currently the absolute trending topic in the industry – and for good reason. While others are still puzzling over how to get a grip on the "forever chemicals" (PFAS/PFC), Stehr delivers a tangible solution with the PEFAS process (PFAS Elimination through Fixation and Adsorptive Stabilization).

The Stehr EXPO: From Nightmare to Solution

It is hardly surprising that this system was the focus of the last Stehr EXPO. For many building contractors and municipalities, the topic of PFAS is currently a costly nightmare. Normally, PFAS in the ground means large-scale excavation, transport across Germany, and storage in special landfills for vast amounts of money.

Stehr turns the game around:

• On-site processing instead of removal
  The treatment takes place directly on the construction site. This saves thousands of costly and climate-damaging truck journeys and massively protects the budget.
• The dust trap solved
  Activated carbon is extremely light and highly dusty. The Stehr SBF 24/6 system works 100% dust-free so that the activated carbon lands precisely in the soil and not in the ambient air.

Tractor with the dust-free Stehr soil stabilization milling machine SBF 24/6 in field-tested use

Technical Precision against Chemical Instability

By mixing in the activated carbon, the pollutants in the soil are "locked up" (immobilized) so that they can no longer be washed out into the groundwater. The highlight of the technology is the combination of the proven Stehr mixer and precise, computer-controlled dosing.

Modern, computer-controlled display for exact dosing

Homogeneously processed soil directly on the construction site

In Storndorf, trade visitors were able to experience live how an ecological burden can be turned back into stable, harmless building ground. This "problem-solver mentality" is exactly what the industry appreciates: A huge problem is solved without turning the solution into a new problem.

Putting an end to logistics madness

The relief in the industry is palpable, as the Stehr PEFAS system fills a massive gap in the market. Until now, PFAS was often the "death sentence" for a construction project or at least a financial bottomless pit. In view of increasingly strict limit values (keyword: Substitute Building Materials Ordinance), a system is now available with which these values can be reliably met.

In addition, the ecological madness is stopped: Anyone who has ever tried to cart tens of thousands of tons of contaminated soil over hundreds of kilometers to the only available landfill knows how urgently this innovation was needed. With the Stehr invention, waste becomes a building material again.

Quality through Homogeneity

The basic prerequisite for success is the exact application and mixing of the carbon. If so-called "nests" arise due to uneven distribution, PFAS can continue to be washed out there.

The Stehr mixers show their advantage here: Thanks to their high power and special tool arrangement, they literally unlock the soil and distribute the carbon microscopically fine.