After half a year of development and planning within the MtecPla Project, we were excited to finally test the capabilities of our detection systems with specially prepared sediment plastic mixtures under controlled laboratory conditions. Within our project partnership we were able to use the 20 m3 water basin in the Maritime Exploration Hall of the German Research Center for Artificial Intelligence (DFKI) in Bremen. The pool allows to create different optical conditions by controlling the incoming light, and it can, for example, be darkened and clouded to simulate changing turbidity of the water column. To be able to conduct these tests in controlled conditions and test different technology in the water, a modular housing was specially constructed by our partner Kurt Synowzik Werkzeug u. Maschinenbau (KSW).

Data Scientist Mischa Ungermann and Development Engineer Nils Öhlmann during testing in the pool of the DFKI. Image: Tobias Winkelmann / planblue

Trays with the plastic samples on the bottom of the pool. Image: Tobias Winkelmann / planblue

We performed multiple tests throughout Spring and early Summer of 2021, for all of which plastic samples were provided by our partner the Institute of Biomaterials and biomolecular systems of the University of Stuttgart and The Ocean Cleanup. Samples consisted of the most commonly used (and found) plastic in the world: PP, HDPE, LDPE, PS, PET, Nylon and PVC. These are, for example, used in the production of disposable cups and plates, trash bags, water bottles, fish nets and packaging.

For testing, the samples were differentiated by color and size (the smallest being 1 mm2, the largest 25 cm2), placed in trays with quartz sand and plunged to the bottom of the pool. Additionally, some samples were degraded beforehand by two different techniques: exposure to sunlight for 1 week (in the controlled environment of a climate chamber) and placing them in a lake for 6 weeks to develop a biofilm on their surface.

To refine our detection system, the first round of data was used to understand and eliminate the effects that different optical conditions have on our data. Now, our team is working on the data from the second round of tests to visualize the state and presence of plastic samples. We will conduct a range of experiments in a lake as well to verify our results in the field.