Two Photonics-Related Projects Identify, Filter Out Microplastics

Two research projects with majority funding from the German Ministry of Education and Research seek to use photonics to address the issue of microplastics. The SimConDrill project will see Fraunhofer ILT join forces with industrial partners to develop a filter that can remove microplastics wastewater. A related project, SIM-QPIa, will focus on analytical methods for treated wastewater. That project will be led by TOPTICA eagleyard with support from the Ferdinand Braun Institut, die Westphalia Datalab GmbH, die Humboldt Universität zu Berlin, die Westfälische Wilhelms-Universität Münster, and the WESSLING GmbH.

Fraunhofer reported that the first laser-drilled microplastic filter is being tested in a wastewater treatment plant. It contains sheets with extremely small holes, just 10 μm in diameter. The technology to effectively drill millions of such holes was developed at the Fraunhofer Institute for Laser Technology. LaserJob GmbH fabricated the filter prototype using the Fraunhofer-developed process. The laser-drilled metal foils have been installed in project partner KLASS Filter GmbH’s patented cyclone filter and subjected to intensive testing. In the first test, the filters removed fine powder from 3D printers in contaminated water. The technology is now being tested under real-world conditions in a wastewater treatment plant.

A prototype filter developed by Fraunhofer ILT has 59 million laser-drilled holes for the filtration of municipal wastewater. Courtesy of Fraunhofer ILT.

The process developed at Fraunhofer is a multibeam process in which a matrix of identical beams is generated from a laser beam via a special optical system. Fraunhofer used the process with an ultrashort-pulse laser to drill holes simultaneously with 144 beams.

In parallel to the drilling application, a consortium of six partners is working on how best to integrate a multibeam processing system into an industrial machine. In the EU project “Multiflex,” researchers and the industry are increasing the productivity of scanner-based laser material processing using multibeam processes. The special feature of this project is that all partial beams can be individually controlled and therefore used to produce any kind of surface structure. The project partners aim to increase the speed of the process by a factor of 20 to 50, therefore making the entire process more cost-effective.

The project led by TOPTICA is developing mobile detection methods for microplastics in water. Currently MIR-spectroscopy is used for the detection and analysis of microplastics. The project seeks to create a compact and robust technology that can analyze samples without complex preparation being required to detect even a small amount of microplastics. The samples will be measured with photons in the mid-infrared range, which leads to improved cleaning stages to ensure less microplastics in water.

TOPTICA eagleyard focuses on the development of hermetically sealed butterfly packages for mobile usage so that the detection of microplastic can be done on-site. The team will work to develop low-voltage assembly and will design high-performance ceramics for effective heat spread. Due to the necessity of mobile usage, a low-power consumption from the thermoelectric electric cooler is essential, though at the same time, temperature control needs to be precise.

The project team led by Hendrick Thiem, development engineer at TOPTICA eagleyard, is evaluating different concepts for the collimation of fiber adjustment as the current state of the art can’t fulfill the requirements. To integrate the optical isolator in the laser module, the team needs to develop a miniature format to fulfill analytic requirements. Additionally, the electrical control for the pump laser and the sensor module need to be downsized to be integrated. As a later roll-out is essential, new manufacturing processes for the micro-assembly will be created.

Completion of the project will see laser modules for quantum sensing as a commercially available technology for industry use. The developed method of detection will decrease costs significantly.