Most of these pellets are usually circular, at least around here. Those pellets are hexagonal. It might make it easier to search for the company if the same holds true in the NOLA area. The process starts out with the pellets in a large container (tank truck, rail car, etc.). The pellets are then moved to the factory, usually by vacuum or air blowing. Which is why a loose hose can lead to a bunch pellets working into the water. The pellets are then molded by any number of different techniques. There are a large variety of colors in the sample. So the industry using the plastic would need many colors. Toys is my first guess, although there are others. If there is someone with access to an FTIR, the polymer could be identified. One of two of the pellets would need to be crushed as thinly as possible to make a film with heated pliers (hot press film) and the run on the IR. The base polymer should be identifiable. Try to use the lightest colored plastic possible for the IR testing. The other way would be solvent cast films. That is to be avoided, if possible.

What kind of filter are you using? is it efficient? Would you recommend using it?

Your work is very impressive. And it seems like you are just a step away from identification. I wish I knew the exact step needed. The pellets are hexagonal in shape, instead of round. That is rare, at least in the north. Was any density testing done on the pellets?