TL,DR: powder laundry detergent is better than the liquid one.
When it comes to choosing laundry detergent, I used to default to liquid detergent because powder would often clump together. However, I recently learned that liquid detergent has a bigger environmental impact - it contains microplastic particles that are hard to remove in wastewater treatment plants, and it's also less efficient at cleaning. Plus, liquid detergent usually comes in plastic bottles, whereas powder detergent is often packaged in plastic film or even cardboard.
So, I switched back to powder detergent. To avoid clumping issues in my humid laundry room, I found a simple solution: I use an old fork to break up the powder before use. It's a small effort, and I'm happy to be reducing my pollution footprint a bit. Video source (in German, maybe this weekend I'll look for better sources and add an infografic): https://youtu.be/HgIe4oxe2eI
I use a liquid because I wash exclusively at 30C, and it's my understanding that powders don't diffuse into the water well at such low temperatures. Can you elaborate on the cleaning efficiency and microplastics? Mine comes in a cardboard carton the way milk does, so I wonder whether it would carry the same issue. (I don't think it would be legal to tell us to sort it as paper if it has a secret plastic lining.)
I do use powder for my dishes though, so I can share a tip. Get a large plastic or metal box with a decent lid so you can pour the powder in and keep it nice and dry so it doesn't clump. It makes it very comfortable to be able to scoop from such a large surface area rather than using the spout on the box.
In the linked video they claim the powder washes better (in addition to the environmental benefits) even at 30°. Also the cardboard boxes for milk DO have a plastic lining, but it's not secret. Otherwise the liquid would destroy the cardboard. But this is OK I think, it gets collected and partially recycled. The "bad" microplastics are inside the liquid detergent itself, to ensure that soap and water remain well uniformly mixed.
how does it compare to liquid at 60f (15.5C)?