Translation:I believe this company recycles waste.
I had this in another form (plain translation of English to French) and used "des" not "les", and it was ok, so I did it again. Now it's "les"? Yes, this was the aural one (I honestly can't hear the difference between les and des at full speed, so I guess a lot, or have to hit the go slow button, which reduces what I can do in my study time), but does that mean that I was incorrect before but got away with it? Or are there two versions and they're being picky based on the format?
when I got this wrong before, it was because I did not place "les" in front of "déchets". I simply wrote "déchets" without any modifying article in front. I was then offered a "hint" that when quantity is unclear, it should be "des". So, it was with some surprise when I put "des" in front of "déchets" the second time around, it came out wrong. Why "les" when the Duo hint itself informs me that it should be "des"?
"Waste in general" does not mean "all the waste in the world". This is a misconception (and unfortunately at least some of the moderators seem to subscribe to it).
In this type of context, it means that they recycle any and all waste that they are given to recycle, not just some of it.